Eartquakes Essays - Seismology, Earthquake Engineering, Free Essays

Eartquakes Essays - Seismology, Earthquake Engineering, Free Essays Eartquakes Earthquakes: Why They Occur And How To Prepare For Them An earthquake is one of the most powerful natural disasters known to man. Earthquakes are so powerful that they can knock down buildings and bridges as well as change river routes and cause landslides. With all the damage earthquakes cause the only way to protect oneself from them is to be prepared and well educated about them. Since they cannot be predicted one must always be prepared for them. Strict building codes in earthquake prone areas also help to minimize the property damage caused during an earthquake. Earthquakes throughout history have caused several millions of deaths as well as severe property damage. Earthquakes are more complex than one may think they are. Earthquakes most often occur near plate boundaries because that is where the tectonic plates meet. As tectonic plates slide past each other they cause tension on one another. After a while there is so much tension on these rocks that they just snap. The sudden break of these rocks send vibrations out in all directions. Soon after the first vibration is sent out a second vibration is sent out called the After shock. Humans can also cause earthquakes in many ways. Injecting fluids into deep well for waste disposal, filling reservoirs with water, and firing underground nuclear test blast, In limited circumstances lead to earthquakes. All these activities increase the strain within the rock near the location of the activities. So that rocks slip and slide along preexisting faults(Microsoft Encarta 2000). Earthquakes can cause a lot of damage. They are strongest near the epicenter. The epicenter is directly above the point that the earths crust snaps. The farther from the epicenter the weaker the vibrations of the earthquake are. That means the area close to the epicenter are going to receive more damage and areas farther from the epicenter are going to receive less damage. As well as distances from the epicenter the type of area an earthquake occurs in has effect on how much damage is caused. Under developed countries seem to suffer much more damage than a developed country. Underdeveloped countries have less strict building codes and are not prepared for natural disaster as well as developed countries are. In underdeveloped countries earthquakes cause much more deaths also. After earthquakes conditions often lead to widespread disease outbreaks. Damage to hospitals, water supply lines, sewage lines, and lack of housing all contribute to the widespread of disease. Developed countries have the same problems but thier strict building codes, emergency forces, and preparedness seem to minimize the damage and death caused by earthquakes. No matter if a person lives in developed or underdeveloped country earthquakes still cause damage. A tsunami is probably the effect of an earthquake. A tsunami is a group of giant sea waves that get bigger and bigger as they get closer to the coast that usually strike without warning. As these giant sea waves come crashing down on the coast they cause servere flooding that drowns a lot of people instantly and cause a lot of property damage. Along with flooding from tsunamis rivers are often rerouted during major earthquakes and flood whole town. After most major earthquakes there are fires. The worst part of fires after an earthquake is that usually broken gas mains cause the fires. If the gas mains are broken usually the water mains are also broken so firefighters have a hard time finding water to put out the fires. Another effect of an earthquake is landslides. Landslides are very dangerous if they occur because most of the time anything in the path of a landslide is destroyed. Earthquakes are very dangerous for a few reasons. First of all they cannot be predicted and second they cannot be stopped. If an earthquake occurs all that can be done is wait it out. That is why everyone must be prepared for an earthquake. The first item that must be learned about an earthquake is that they can occur at any time and any place. Two procedures that must be done in order to prepare for an earthquake is make an earthquake kit and prepare ones home for an earthquake. The basic earthquake kit should include food

The History of the Tea Party From Its Beginning to Now

The History of the Tea Party From Its Beginning to Now The tea party movement may only be a few years old, but the beginning of the movement is often misunderstood and misreported. While the tea party is often portrayed as being purely an anti-Obama movement, the truth is that the Republican Party has always been as much a target as President Obama and the Democrats. The Tensions Rise During the George W. Bush Years While the tea party may have formerly started after Obama took office, anger over federal spending and a rapidly bloating government began to surface during the big-spending years of the George W. Bush administration. While Bush scored points with conservatives on his tax policies, he also fell into the trap of spending too much money that didnt exist. He pushed for a large expansion of entitlements and, most dangerously, continued the Clinton-era policies that led to the collapse of the housing market and financial industries. While conservatives opposed these big spending measures, it is also true that they lagged far behind their liberal-counterparts in vocalizing anger, showing up at Capitol Hill to protest, or rallying thousands of people at any given time to support a cause or oppose a policy. Until the rise of the tea party, the conservative idea of activism was to shut down the congressional switchboard. Yet despite one disappointment after the next from our elected leaders, voters continued to send the same people back year after year. It would take a major economic crisis to help Sarah Palin Rallies a Crowd Prior to the 2008 elections, it seemed as though conservatives had no clue how to rally a crowd around a cause. While they had their moments - opposing Bushs immigration policies and Supreme Court nominee Harriet Miers to name twoa real movement was hard to come by. But in 2008, John McCain selected Sarah Palin to be his vice-presidential candidate and suddenly the Republican base did something they never really did before: they showed up. When Palin joined the Republican ticket, people suddenly started attending rallies. McCain events had to be moved to larger venues. Rather than attracting hundreds of people like McCain had been doing, Palin was attracting thousands instead. Palin was hard-hitting, despite being seemingly restrained by the establishment. She gave one of the greatest convention speeches ever, where she hit out at Barack Obama and saw her popularity soar. She connected with people. And while she was eventually destroyed and rendered ineffective during the 2008 campaign, her ability to actually get thousands of people to rally for a cause would jump-start the future tea party movement, and she would eventually become the top draw at future tea party events nationwide. Rick Santelli Delivers a Message Shortly after his inauguration in January of 2009, President Obama began pushing the American Recovery and Reinvestment Act, a package costing close to $1 trillion. Already infuriated with the final years of the Bush administration that saw multibillion-dollar bailouts and payoffs, conservative outrage of the fiscal insanity was escalating rapidly. After the package passed, CNBC personality Rick Santelli took to the airwaves to deliver what would be the final spark to ignite the tea party flames. In what turned out to perfectly summarize tea party sentiment, Santelli took to the floor of the Chicago Stock Exchange and stated the government is promoting bad behavior... This is America! How many of you people want to pay for your neighbors mortgage that has an extra bathroom and cant pay their bills? Raise their hand.  When the floor traders started booing the government policies, Santelli dropped the President Obama, are you listening?  line. In the rant, Santelli also stated that Were thinking of having a Chicago Tea Party in July. All you capitalists that want to show up to Lake Michigan, Im gonna start organizing.  The clip was widespread, and the first tea party rallies were held eight days later on February 27th, 2009, where tens of thousands of protesters showed up in over 50 cities to voice opposition to the Bush and Obama spending sprees. Tea Party Targets Republicans and Democrats Challenging Democrats in November elections is always a fun thought for tea party members. But it is not their first goal. The tea party does not exist to challenge only Democrats simply to return the same Republicans who rubber-stamped the big government Bush agenda for eight years. And this is why the first victims of the tea party in any given election cycle are always Republicans. The first goal of the tea party was to target liberal Republicans up for reelection. Arlen Specter (PA), Charlie Crist (FL), Lisa Murkowski (AK), and Bob Bennett (UT) were just a few of the many politicians backed by the mainstream GOP but opposed by the tea party. Specter saw his time was up and bailed to join the Democrats. When Crist realized he was soon to lose to a young conservative star in Marco Rubio, he jumped ship and ran as an independent. Bennett was so unpopular he couldnt even earn a primary slot. Murkowski lost her primary also but was eventually saved by the Democrats after launching a write-in campaign. Only after getting a strong foothold in the Republican Party by knocking off incumbent or establishment Republicans would the tea party focus their attention on Democrats. As a result, the myth of the blue dog  Democrat was mostly destroyed and the GOP decimated the ranks of so-called conservative Democrats.  It would be over three years since the start of the tea party movement before conservatives would have a shot at President Obama. The number of Republicans that the tea party has brought down is proof enough that this is about more than just one man. Final Takeaway The tea party does not exist because of one individual. It exists as a result of the constant and rapid growth of government under both Republican and Democratic-led governments. The tea party does not care whether there is a D or an R next to a politicians name or whether a politician is black, white, man, or woman. If a Republican is elected president, the tea party will exist to hold him just as accountable as they hold President Obama. Anyone seeking proof can ask any of the many moderate Republicans who have been ousted in primaries for failing to follow the principles of limited government.

Community Health Nursing Essay Example | Topics and Well Written Essays - 750 words

Community Health Nursing - Essay Example Parish nurse links faith and health care to advocate ministry and this includes preaching in addition to healing people. School nurses are those who are based in academes who attend to the medical needs of students and school employees. I would ask them to coordinate with their local health professionals and seek to advise on how to properly take care of their health such as practicing good sanitation, eating right, exercising regularly, etc. Young children and senior citizens are typically vulnerable to communicable diseases because their immune system is weak. But with the spread of HIV, perfectly healthy people are also vulnerable. For young people, I would always advise them to practice good hygiene and sanitation not only with their bodies but with their surroundings as well to prevent the transfer of communicable diseases. With regard to HIV, I would advise people to wear protection during sex. Active immunity is the immunity that develops after giving the primary immune response which is the exposure to live pathogen and development of symptoms. The cells that are produced by active immunity is the antibodies themselves. Passive immunity is the form of immunity that a person gets by getting immunization such as folio vaccine whereby the antitoxin or antibodies are injected into the person. Primary prevention involves the avoidance of contraction and/or transmission of diseases. They could be done through a set of preventative measures such as practicing good personal hygiene and sanitation, receiving vaccines etch. Secondary prevention includes the early detection of diseases so that prompt intervention may be administered to control the disease and minimize illness and deaths. This could be done through screening, etch.

National Strategy for Counter-terrorism Essay Example | Topics and Well Written Essays - 1000 words

National Strategy for Counter-terrorism - Essay Example The (FID) foreign internal defense are terms used in programs that are meant to either reduce or suppress the favorable conditions that would promote the insurgent conditions, in this overview the response and detection of potential acts or threats describe the principals of counter-terrorism. This paper argues that the overarching goals articulated in the National Strategy for Counterterrorism increase U.S. military involvement in the types of small wars. Small wars from the view of many theorists can be described as strife between irregular and regular forces, this definition extends even to the encompass regular troops in different event or cases that demand their presences and responses like in variable context like in roles of national interest ,politics or culture. If the so-called small wars are analyzed from the political perspective, it is evident that the opponents whenever decide to stand their ground rarely succeed in direct pitched battles. As opposed to traditional rebe llious tribesmen, the modern arenas of warfare record some irregularities in their adversaries. As compared to the past, the sole means was through psychological and political warfare. In this general understanding, success in small wars therefore must include effective means of undermining legitimacy of the adversaries. This means that small wars have to include strategies ranging from peacekeeping, response, small-combating units, and operational as means of survival (Caraccilo 3). The small wars information is a remarkable modern counterinsurgency, counterterrorism, peace operations and other irregular operations remarkable anticipation. In some cases like the argument passed by the United States on the Marines that best strategy was to separate and intervene between warring factions through their negotiations and eventually reach an amicable settlement that does not involve fighting. The best strategy in other situations was to impose order, intervene and create new governments. In the latter, instance the fact that the overarching aim in the interests aligned new polity with the U.S. Nevertheless, the marine asserted that the sole purpose should be on the protection of the citizens and people through the government. These strategies in relation to terrorism are driven by extreme ideologies that often have global implications and possible new realities. These ideologies and violence embracing from the divergent responsible groups can achieve a reach globally. This new reality’s impact is that there are diverse effects from the terrorist attacks on the country’s interest regardless of where there are issues or attacks occur (Ravndal 7). The National Strategy for Counter-terrorism articulate overarching goals of the countries involved, such as the U.S. military and its involvement in counter-terrorism strategies as described in article 8905. It shows that the effects of the small wars and the new realities brought in by terrorist attacks on the country. As such, the country is forced to constantly intervene in the interference. This causes drastic and negative effects since the contemporary conduct of the military activities that take place in contested social norms and legal terrains, the engagement of military forces in armed conflicts conventions, antiterrorism, counter-conspiracy, enforcement of peacekeeping, law enforcement or stability operations result to deaths and even destruction of property. Through this, there is a dense mixture of law through

Strategies and Plans Adopted by Businesses in the Recession Essay Example for Free

Strategies and Plans Adopted by Businesses in the Recession Essay The long-term strategies and short-term plans adopted by businesses in the recession The recession has different impacts/effects on businesses/organizations as all businesses do not operate in the same market/sector. This causes the need for businesses to come up with strategies and plans for business survival. Strategies and plans adopted by businesses are tactics developed by businesses to aid them reach a particular goal/target. Plans adopted by businesses help them look ahead, focus on key points and prepare for opportunities and problems. Then strategies are developed to assist the aim of the plan to eliminate or reduce flaws to make sure the plan is carried out successfully. Burger King (BK) and McDonald’s (McD’s) although both operating in the restaurant/fast food market, they both dealt with the recession differently. BK planned to increase sales by drawing in more customers and survive through a pricing strategy change and investments. They sold some of their products at a loss in order to cope with the recession as consumers were looking for cheaper value meals. I think the purpose of this plan was to increase the profitability of the business. This forced competitors to sell their products at a loss to try and increase sales and stop BK from benefiting from the current recession as it has a well-known brand name which spelt trouble for smaller competitor businesses. BK’s low price strategy was heavily skewed towards poorer economic groups in the US who have been hit particularly badly by unemployment this made their prices reasonable and affordable by all income groups. Focusing on customers from the poorer economic group might have helped boost sales as they and other customers not hit by unemployment would be able to make purchases without great concern. As BK’s sales during the 2006 trading period was weak, they invested $3m to strengthen its UK operation and a marketing push has since paid off. Part of the investment was put towards the development of products which as a result Angus Burgers and the spiced up Angry Whopper were created. A spokesman said these products have played well which means their strategy worked and the investment wasn’t in vain as they achieved a 13% rise in quarterly profits to $50. 2m (? 31. 7m) as stated by guardian. co. uk. BK’s menu remains unchanged centred on burgers, fries and fizzy drinks trying to gain more sales from repeat customers. Being narrowly focused in the recession is not such a good idea as the whole economy is affected by the recession even though it has a greater impact on some groups. BK’s strategy is a dangerous strategy because they are relying heavily on old repeat customers. If those customers changed their taste, it would have a huge impact on BK’s sales and solutions to their situation could be being used by McDonalds leaving BK with no room to improve their performance. The best way to go about a situation like this is to focus on a strategy that would benefit and target everyone bearing in mind the areas which have been heavily affected to assist in controlling price levels. Using the full potential of the business/extension strategies could help save a business from a recession. This could create a loss in the short run but the business can recoup its costs in the long run if successful. However, McD’s approach to the current recession is different compared to the plans and strategies adopted by BK. BK is narrowly focused compared to McD’s as McD’s provides a variety of menus like the breakfast and the kids meal menu. McDs has diversified into salads, Panini’s and cappuccinos in the hope of satisfying so-called soccer mums which is a strategy to attracts more customers. By diversifying its products, McD’s is able to attract different types of customers like healthy eaters and regular caffeine takers. This expansion of product range strategy widens their target customers range allowing them to increase sales and market share. British Airways (BA) operating in the airline market tackles the recession completely different from McD’s and BK. During the recession, according to BA’s first half (April September) pre-tax profit and loss chart, their profits dropped dramatically from roughly ? 610m to ? 50m according to the chart given in the period 07/08 to 08/09 which is around the time the recession begun. They went on to make a further loss of ? 292 Million in the 09/10 period. This sparked a cause for concern. BAA adopted a short-term plan which was heavily centred on the workforce as the airport’s operator was believed to be overstaffed. They decided to reduce the number of staffs and advice some workers to work for free in order to cut labour cost expenditure (inc. Bonuses and allowances) to reduce the loss their making to stay in the competition. Chief executive Willie Walsh and 800 workers agreed to work for nothing voluntary in the month of July to help the company survive and reduce expenditure. This strategy although would help, it brings disadvantages. From this plan, their employer name brand will be affected as a lot of the staff will be unsatisfied causing the union to get involve and also affecting BAA’s operations which in turn affects their customers as the airline will not be operating effectively and running smoothly causing disturbances and leaving customers displeased. The recession causes businesses to come up with plans and strategies in order to survive and stay in the competition. BK, McD’s and BA all adapted different plans and strategies to survive. BK remained firmly rooted in their burgers, fries and fizzy drinks menu, reduced their pricing levels, invested in the launch of new products and marketing and also, targeted those hugely affected by the recession to gain sales by reducing their prices for some products for the population with a low income; charging both high and low prices in other words their pricing strategy was universal pricing (appealing to everyone upper, middle and lower class). Their rivals adopted a different strategy and plan although they both operate in the same market. McDonald’s diversified their products – introducing new products to target other types of consumers i. e. â€Å"soccer mums† as it already has menu’s which targets other consumers like children and healthy eaters. Also, they ran plenty of bargains and distributed gazillions of coupons which played a good part in their survival. BA was making a huge loss so they reduced the amount of employees as a means of cutting expenditure to help them survive. This strategy caused complications for their operations which left customers dissatisfied during the crisis and also the trade union decided to get involved as some of BA’s staff disagreed to the changes that was to take place.

Advancement in Technology: How it has Lead to a Decrease in Writing Sk

Advancement in Technology: How it has Lead to a Decrease in Writing Skills It’s the 21st century, and technology is rapidly moving more into people's everyday lives, especially as the interest in computers grow. The advancement with computers alone has increased drastically, faster than some would have ever imagined. For the most part, this advancement in computer technology has skyrocketed businesses and eased our lives as a whole in society. However, technology doesn’t always have a positive influence on our lives. In fact, it has the potential to harm a major area of our communication skills if not used carefully. It has been shown that technology is one of the factors as to why writing skills have decreased in the past years. With our nation’s writing skills in a slump, it’s important to note the reasons as to why this trend has started and put an end to it as soon as possible. Computers should be used as a language-learning tool in the classroom, just as any other piece of equipment like a tape recorder or VCR. No one can argue that the computer is one of the most influential tools developed in education. However, in school especially, it seems as if the use of computers has become the center of attention in class lessons, which is where the problem comes in. If for instance, there is a situation when activities at the computer could become the center of attention, teachers should be using more discretion in this area than they currently are today. Relying on computers for every aspect of a lesson will greatly have an effect on a student’s writing capabilities, and it isn’t a positive one. When students are interacting with a computer, they are also using motor skills as well. These motor sk... ... 3e/students/rcd/rcd_ch05.html Haney, W. & Russell, M. (1997). Testing writing on computers. Education Policy Analysis Archives, 5(3), Retrieved October 17, 2004, from Peer-Reviewed Scholarly Electronic Journal database. Jones, Rebecca (Oct1995). Education Digest. Writing Wrongs, Volume 61, page 63. Poor Writing Blamed on Little Practice, Poor Instruction (July 10,2003). Retrieved October 17, 2004, from http://abclocal.go.com/wabc/news/wabc_ourschools_071003writing.html Toner, Erin (1997). Graduates lack computer, writing skills. Resources from state news staff. Retrieved October 17, 2004 from http://www.statenews.com/editionsfall97/082997/p1_study.html Using Technology to Enhance the Writing Processes of Students with Learning Disabilities (1996, July). Retrieved October 17, 2004, from http://www.ldonline.org/ld_indepth/technology/tech_writing.html

Koreanovelas: Now a Better Media than Local Teleseryes?

Eventually, some would start to watch every episode of these shows, seeing it as â€Å"something new'. In contrary, Korean dramas, locally known as Cornflakes, have been aired in our country for more than a decade now. In fact, a lot of people grew up watching them. These shows are really nothing new to us, but why do we patronize them? Why do a lot of people prefer them over our own shows? It's mainly because we're seeing something different, better and fresh in Cornflakes.Cornflakes are undeniably one of the latest trends in our country, making us one of the places greatly hit by the throng current of the so-called Halley wave or Korean wave, that refers to the rapid spread of Korean entertainment in Asia. The Halley wave consists of mainly Cornflakes, Korean pop (Kop) music, fashion, cosmetics and home appliances, though it is believed that Cornflakes are the ones that started it all. Cornflakes have reached our country in the year 2003, Bright Girl being the first show of this t ype to be shown.Cornflakes aren't an instant hit here in the Philippines. It only reached the first peak of its popularity through the show entitled Endless Love. The said drama is greatly known through the say recognition of the names Johnny and Jenny, the Pipelined names of the characters of the story. This was greatly followed by the success of Lovers in Paris, Full House, Jewel in the Palace, Stairway to Heaven, and many more. Since then, Filipinos have been keeping an eye out for the next Cornflakes to be shown in the country.Though we are greatly aware of the popularity of Cornflakes in our country, there has been no concrete idea or concept on why these have gained a great number of Filipinos patronizing them. (For You In Full Blossom, 201 1) There are two possible reasons behind the fast entry ND widespread patronizing of Cornflakes in the Philippines: (1 ) Cultural globalization of Korea and (2) Cultural neo-colonialism of Korea in the Philippines.According to weeklies , cu ltural globalization is the rapid movement of different ideas, attitudes, and values across national borders that results to the standardization of cultural expressions in different countries. The Halley wave is one example of cultural globalization. Now that it is considered as a big part of Koreans export materials, their culture and ideas involved in the wave are rapidly spread all throughout the globe, specially in its neighboring Asian countries. Neo-colonialism, on the other hand, refers to an extension or maintenance of influence of a country over another (Merriam-Webster, 2014).In a study conducted by Aimer Associable and Johnson Eosin of the Mindanao State University entitled â€Å"Koreans Philippine Invasion†, it stated that the Philippines is now under the neo- colonization of South Korea. It is described as a form of colonialism that uses diverse art and culture to influence another country or area. Such colonialism is described as enjoyable and exciting and not b loody r catastrophic and that is the reason why Filipinos are not fighting against it, but instead are patronizing it. (Associable, Eosin, 2013) As part of our culture, Filipinos are very accommodating, not only towards new people but also towards new ideas.This is one of the reasons why we welcome the perspectives of other countries easily and without hesitation and thus forming the idea that â€Å"anything foreign is good†. Even before Cornflakes reached the Philippines, there has been a number of foreign TV shows that have been aired here in the country, such as Marimba (1996) from Latin America, and Meteor Garden (2003) from Taiwan. For You In Blossom, 2012). Popularity in our country mainly refers to the number of viewers of the show, and the shows mentioned were considered successful due to the high number of followers that watched them.In the same way as people in the Philippines welcomed Marimba and Meteor Garden, we accepted Cornflakes with open arms, even though the ideas from their shows are very different from ours and new to us. For example, Philippines was never an imperial country and the idea of a kingdom or an empire was not ordinary to us. But Cornflakes have offered to us stories of Koreans different misdoings and dynasties. Since this concept was not ordinary, it lead to people becoming more curious of it, budding questions like, â€Å"What does it look like? ‘ and â€Å"How does it work? ‘ and they watch the new shows to gain answers.In terms of new people, Cornflakes have offered to us new actors and actresses to idealize. Idealization refers to the excessive admiration of or devotion to a person (Merriam-Webster, 2014) and it has been a part of the behavior of Filipinos who love watching television to idealize. Idealization, in simple terms, means imitating their idols' way of dressing and speaking and itching their every move and this is very evident nowadays, especially to the teenage generation. We can see people now on the streets wearing clothing and (sometimes) hair with cheerful colors, imitating their Korean idols.Not only are those, but people also are now very fond Of eating Korean food and some also learn the Korean language, also known as Handful, which are commonly seen and heard in Cornflakes. In this whole process of cultural globalization and neo-colonization, Koreans striver to improve a lot of aspects in their dramas. Now, its not only because Cornflakes are a part of the Halley wave. It is now about having the high quality sets, artists and plots that piques the interest of the eyes of the Filipinos.Though both of the dramas from Cornflakes and our local telemeters are good sources of entertainment and cultural knowledge, Korean dramas are better than Filipino dramas in terms of the different elements involved in the production of these television series such as the story line and pace, staging and blocking of scenes, and the actors and actresses that portray the drama's char acters. Despite the growing popularity of Cornflakes, their ratings on our local Hansel have remained low, relative to our local telemeters.

Solder Joint In Electronic Engineering Essay

Electronic makers throughout the universe have a long history of utilizing lead-based solders. These solders have proven to be cost effectual and high reliable, and are solidly integrated into fabricating methods and procedures. Driven by statute law chiefly in the European Union i.e. WEE, RoHS, EEE Directives, makers are concrete the manner for taking lead solder from all electronics assemblies. However, the credence of nonleaded solder posses many draw dorsums. Conversion to RoHS ( Restriction of Hazardous Substance ) compliant parts must include the full merchandise development and fabrication procedure. To electronics makers, one of the most of import facets in the procedure is guaranting the nonleaded solder articulation dependability is equal to or greater than that of their current leaded solder composings. Manufacturers are working independently to formalize dependability for their nonleaded electronic constituents and systems. Likewise, industry organisations and other research workers have developed proof plans that attempt to understand failure mechanism associated with nonleaded merchandises, generate dependability acceleration theoretical accounts, and predict the dependability of nonleaded solder articulations. Several theoretical accounts of lead free solder articulation dependability non mature plenty yet to enable alone demand of aerospace and military intent. Several factors affect solder articulation dependability, i.e. portion geometry, solder drosss, and external environmental emphasiss. Rapid thermic cycling has been an effectual environmental stimulation capable of bring oning weariness on solder articulations, peculiarly with stuffs holding mismatched thermic enlargement coefficients. Mechanically induced quiver is another external emphasis that efficaciously evaluates solder joint dependability. Thermal cycling can bring forth high supplanting emphasiss at low rhythm frequences, whereas mechanical quiver can supply low supplanting emphasiss at high frequences and high rhythm counts. A peculiar type of trial equipment and methodological analysis capable of using a combination of rapid thermic cycling and quiver is Highly Accelerated Life Testing ( HALT ) . Circuit boards range from simple individual moulded plastic boards with Cu music directors on one or both sides to multilayer boards with Cu music directors, each bed being separated by a insulator and interconnected by metal music directors. Minimum line breadth and spacing between lines is less than 100 A µm. The board typically is made from a composite such as an epoxy with superimposed sheets of woven fiberglass. The dielectric stuff between beds of music directors is normally a polymer, for illustration polyimide. To keep solder ability, the exposed Cu may be coated with an inhibitor such as benzotriazole or with a solder greatcoat. Components are attached to the board with solder or metal-filled conductive adhesives. Fully assembled boards may be farther protected against wet, taint, and mechanical harm by a screen coat. ( Steinberg D,1988 )1.2 SOLDER JOINT RELIABILITY AND FAILURESolder articulations widely used in the electronic packaging industry to bring forth good electri cal, thermic, and mechanical connexions between the bundle and the printed circuit board. Twenty per centums of the mechanical failure in airborne and mechanization electronic cause by quiver and daze. Design appropriate step to guarantee the survival equipment in the daze and quiver environment is necessary to make so. Staying 80 per centum of mechanical failure related to thermic emphasiss ensuing from high thermic gradients, coefficient of thermic enlargement and high coefficient of snap. Solder joint failure occurs in several grounds: Poor design of the solder articulation A bad solder articulation intervention Solder stuff Excessive emphasis applied to solder articulations. In general, nevertheless, the solder articulation failures are merely graded harmonizing to the nature of emphasis that have caused. Most joint failure falls into three major classs: Fatigue failure due to cyclic emphasis application Due to the execution of a long term or lasting burden The emphasis is due to overloading in the short term Reflow profile besides has a important function on solder articulation reliablity. Because It besides has a high influence micro construction of the solder articulation. Vibration failure of solder articulations is assessed for dependability utilizing high accelerated life trial, which is represented by a GRMS- clip curve. For surface saddle horse microelectronic constituents, an estimate of printed circuit board ( PCB ) theoretical account analysis can be made by presuming PCB as a bare unpeopled thin home base because the addition in stiffness of PCB due to the climb of the constituents is about offset by the addition in entire mass of the populated PCB. However, this estimation can direct to mistakes in natural frequence computation for different bundle profiles, for flip-chip-on-board ( FCOB ) and plastic-ball-grid-array ( PBGA ) assemblies. When the constituent has little profile, the estimate of PCB assembly as a bare PCB can supply acceptable average analysis consequences because the stiffness and mass part of little constituent to PCB assembly is non considerable. In this trial, changing GRMS-level random quiver trial for PCB assemblies were conducted. In order to cipher the dependability of PCB assembly, it is necessary to carry on the dynamic analysis.1.3 PROJECT PURPOSEIn this modern universe due to the causes of wellness and environmental issues the electronic fabrication industries confronting a challenging job of necessity to bring forth dependable solder merchandises in really high denseness with really low cost. Solder articulations are really of import to the dependability of Printed Circuit Boards ( PCB ) . This is a 1 of the taking factor in transmittal of electrical and thermic connexions. In instance of every PCB even a smaller solder articulations are really of import. So this undertaking investigates the Effect of quiver on solder articulation dependability in electronics assembly applications. Solder articulation of an electronic assembly is really of import measuring because of this theoretical account based survey might assist applied scientists efficaciously better the PCB mechanical design and therefore better dependability of electronics attached to the PCB by sing practical uncertainnesss and inauspicious quiver environments. This experiment attempted to research the usage of HALT to measure the dependability of solder articulations. For this trial, samples of PCB ‘s arranged and tested on an Environmental testing chamber. The trial program included a response where, as samples become displaced from the printed circuit board ( PCB ) , . In add-on, a solder joint life distribution would be bring forthing depicting comparative public presentation between Sn95.5/Ag4.0/Cu0.5 vs. Sn42Bi57Ag1 solder paste. The consequence of this trial did non bring forth the sequence of failures necessary to be after the life informations ; nevertheless the procedure of proving revealed near by into the application of HALT as a technique to contrast the public presentation of PCB soldered constituents. ( Steinberg D,1988 ) The overall research methodological analysis that has been followed during the undertaking is illustrated in Figure 1.1. There are six distinguishable stairss: Literature Survey, Project Planning, Design of Experiments, Experimental work, Analysis of consequence and Conclusion, and Documentation and Presentation. Literature Survey Design of Experiments Undertaking planning Experimental Work Analysis of Results and Conclusion Documentation and Presentation Figure 1.1: Undertaking MethodologyChapter 2LITERATURE REVIEW2.1 SINUSOIDAL VIBRATION TESTINGDynamic warps of stuffs caused by quiver can do jobs and malfunctions including failed electrical constituents, deformed seals, optical and mechanical misalignment, cracked or broken constructions, inordinate electrical noise, electrical trunkss, chafed wiring. Because sine quiver represent largely a certain cardinal frequence and the harmonics of that cardinal, in its pure province, this type of quiver is generated by a limited important figure of beginnings. Expressed as amplitude versus frequence, sine quiver is the type of quiver generated in the field by beginnings such as engine rotational velocities, propellor and turbine blade transition frequences, rotor blade transition and launch vehicles. While much of â€Å" existent universe † quiver is random, sine quiver proving accomplishes several of import ends in merchandise ability and proving. Much stuff and completed merchandise was modelled on some type of sine quiver signature. A sine expanse of frequences will reason whether the premises were right and if the divergences are considerable plenty to do design alterations. In other words, expanse will set up if the imagined frequence has been met and/or discovers the trial point cardinal frequence. Similarly, a expanse will assist place the trial capable resonance frequences, which may be the points at which the point experiences peculiarly nerve-racking warps. Some of the undermentioned trials include fixed frequence at higher degrees of the commanding variable ( displacement, speed, acceleration ) , and random quiver. Another typical sinusoidal quiver trial, sine explosion such as the teardrop, goes quickly to top out pulsation and so decays at lower rate ( to forestall harm to the unit ) . The burst trial puts a maximal burden into an object at a rapid rate and peculiarly emphasiss articulations and seams to place craft and design issues.2.2 RANDOM VIBRATION TESTINGThe genuineness of random quivers an effectual tool of testing craft defects came about during fabrication. Up until that limited hertz sine was applied during dependability proving. Pure sinusoidal quiver is composed of a individual frequence at any given clip. Comparisons trials revealed that to be the effectivity of random quiver. The trial point will hold to be subjected to many sine frequences over a longer period of clip, and may by happenstance weariness the trial point. Random quivers undercover defect faster. Another fluctuation would be a swept sine on random trial. In random quiver nevertheless, all frequences happening at the same time. Because of this, random quiver analysis normally performed over a big scope of frequences, say from 20Hz to 2000Hz. Research workers are non looking at a specific frequence, specific minute in clip or specific anything else ; They are statistically looking at a construction response to a given random quiver environment. Decidedly be cognizant about any natural frequences that cause a big random response at any open frequence degree, but largely all the experiments taking the overall response of the construction. Random quiver analysis looks at random accelerations or forces over a scope of frequences, which we call the frequence sphere. ( These random inputs are merely sustained over a period of clip, but are non time-dependent ; i.e. , the longer the period of clip, the better the statistical sampling in the frequence sphere. ) The scope of frequences is called a spectrum. Therefore, this is called by Spectral Density. Normally, if accelerations consider in trial, for that Acceleration Spectral Density ( ASD ) have to utilize.2.3 SINE ON RANDOM VIBRATION TESTINGVibration sine on random testing is executing by superposing a sine moving ridge on top of a random environment. A sine on random quiver trial replaces the combined environment of a spinning chopper blade with its distinguishable resonant degrees and the remainder of the aircraft which generates random engine and aerodynamic induced quiver. Gunfire on board an aircraft causes sine quiver while the remainder of the aircraft generates random excitements. These types of trials are doubling quiver Characterized by dominant extremums ( sinusoids ) superimposed on a broadband background. 2.4 Real WORLD SIMULATION. Most quiver in existent universe is random for illustration a vehicle traveling over route feels random quiver from the route abnormalities. Land launched projectile vehicles exposed to non stationary quiver during its flight, the motor ignites the projectile travel through the ambiance, the motor burn terminals and so forth even in flying when subjected to turbulent air flow, undergoes random quiver. Random quiver is composed of battalion of continues spectrum of frequences. Movement varies indiscriminately with clip. It can be accessible in the sphere by a power spectral denseness map [ G2/Hz ] .2.5 HIGHLY-ACCELERATED LIFE TESTING ( HALT )HALT involve quiver proving in all three axes with a random manner of frequences. at last, HALT proving can include the real-time cycling of multiple environmental variables, for illustration, temperature cycling plus quiver testing. This multi-variable proving attack provides a closer appraisal of real-world operating environments. Unlike usual testing, the end of HALT proving is to interrupt the specimen. When the merchandise fails, the weakest point is recognized, so applied scientists know closely what demands to be done to develop merchandise quality. After a merchandise has failed, the weak constituents are upgrade or toughened. The revised specimen is so subjected to an extra unit of ammunition of HALT proving, with the scope of temperat ure, quiver, or floor further increased, so the merchandise fails once more. This identify the following weakest point. By traveling through several proving like this, the merchandise can be made rather strong. With This familiar attack, merely the weak musca volitanss are identified for betterment. This type of proving supply so much information about the assembly and public presentation of a merchandise, that it can be rather supportive for newer applied scientists assigned to a merchandise which they are non wholly familiar. HALT proving must be performed during the design period of a merchandise to build the basic design is dependable. But it is indispensable to observe that the units being tested are likely to be hand-made technology paradigm. At suggestion, we have found that HALT proving should besides be performed on existent industry units, to guarantee that the passage from technology design to production design has non resulted in a loss of merchandise quality or hardiness. Some applied scientists may see this attack as scientifically sensible, but economically impractical. though, the cost of HALT proving is much a lesser sum of than the cost of field failures.2.6 HIGHLY-ACCELERATED STRESS SCREENING ( HASS )HASS testing is an ongoing showing trial, performed on usual production units. Here, the thought is non to damage the merchandise, but instead to verify that existent industry units continue to run decently when subjected to the cycling of ecological factors used during the HASS trial. The bounds used in HASS proving are based on a skilled probe of the HALT proving parametric quantities. The importance of HASS proving can be suited when 1 considers today ‘s typical production scenario. Natural stuffs are purchased from a seller who uses stuffs purchased from other sellers. Components and sub-assemblies are obtained from makers all over the universe. The finishing gathering of the merchandise is performed by a subcontractor. This manner that the quality of the concluding merchandise is a function of the quality of all the constituents, stuffs, and procedures which are a portion of that concluding merchandise. These constituents, stuffs, and procedures c an and make alter over clip, in that manner impacting the worth and dependability of the concluding merchandise. The best manner to guarantee that fiction units continue to run into dependability aims is through HASS testing.2.7 RELIABILITYDependability is definite as the chance that a device will execute its required map under stated conditions for a exact period of clip. predict with some grade of Confidence is really dependent on right specifying a figure of parametric quantities. For case, taking the sharing that matches the information is of primary importance. If a right distribution is non chosen, the consequences will non be dependable. The confidence, which depends on the sample size, must be adequate to do right determinations. Individual element failure rates must be based on a big adequate population and of import to truly reflect present twenty-four hours normal uses. There are experimental considerations, such as influential the incline of the failure rate and cipherin g the activation power, every bit good as ecological factors, such as temperature, humidness, and quiver. eventually, there are electrical stressors such as electromotive force and current. Dependability technology can be slightly conceptual in that it involves much statistics ; yet it is technology in its most reasonable signifier. Will the design execute its proposed mission? Product dependability is seen as a grounds to the stamina of the design every bit good as the unity of the category and fabricating committednesss of an societies. One of the rudimentss of understanding a merchandise ‘s dependability requires an apprehension of the estimation of the failure rate. The conventional method of finding a merchandise ‘s failure rate is through the usage of accelerated quiver runing life trials perform on a sample of Devicess. The failure rate obtained on the life trial sample is so extrapolated to end-use fortunes by agencies of prearranged numerical theoretical accounts to give an appraisal of the failure rate in the field application. even though there are many other emphasis methods engaged by electronic assembly makers to to the full separate a merchandise ‘s dependability, the informations generated from operational life trial sampling is the major method used by the production for gauging the failure rate of a electronic assembly in field service.Failure Rate ( I » )Measure of failure per unit of clip. The utile life failure rate is based on the exponential life distribution. The failure rate typically decreases somewhat over early life, so stabilizes until wear-out which shows an increasing failure rate. This should happen beyond utile life.Failure In Time ( FIT )Measure of failure rate in 109 device hours ; e. g. 1 FIT = 1 failure in 109 device hours.Entire Device Hours ( TDH )Th e summing up of the figure of units in operation multiplied by the clip of operation.Average Time between failures ( MTBF )Dependability is quantified as MTBF ( Average Time Between Failures ) for repairable merchandise and MTTF ( Average Time To Failure ) for non-repairable merchandise. A right apprehension of MTBF is of import. A power supply with an MTBF of 40,000 hours does non intend that the N = Number of units under trial. If the MTBF is known, one can cipher the failure rate as the opposite of the MTBF. The expression for ( I » ) is: where R is the figure of failures. Once a MTBF is calculated, chance can deduce from following equation:R ( T ) = e-t/MTBFConfidence Level or Limit ( CL )Probability degree at which population failure rate estimations are derived from sample life trial. The upper assurance degree interval is used.Acceleration Factor ( AF )A changeless derived from experimental informations which relates the times to failure at two different emphasiss. The AF allows extrapolation of failure rates from accelerated trial conditions to utilize conditions. Since dependability informations can be accumulated from a figure of different life trials with several different failure mechanisms, a comprehensive failure rate is desired. The failure rate computation can be complicated if there are more than one failure mechanisms in a life trial, since the failure mechanisms are thermally activated at different rates. Equation 1 histories for these conditions and includes a statistical factor to obtain the assurance degree for the resulting failure rate.The Bathtub CurveThe life of a population of units can be divided into three distinguishable periods. Figure 1 shows the dependability â€Å" bathtub curve † which theoretical accounts the cradle to sculpt instantaneous failure rates vs. clip. If we follow the incline from the start to where it begins to flatten out this can be considered the first period. The first period is characterized by a decreasing failure rate. It is what occurs during the early life of a population of units. The weaker units die off go forthing a population that is more strict. This first period is besides called baby mortality period. The following period is the level part of the graph. It is called the normal life. Failures occur more in a random sequence during this clip. It is hard to foretell which failure manner will attest, but the rate of failures is predictable. Notice the changeless incline. The 3rd period begins at the point where the incline begins to increase and extends to the terminal of the graph. This is what happens when units become old and get down to fail at an increasing rate.Figure 2.1 bath bath curveReliability Predictions MethodsA batch of clip has been spent on developing processs for gauging dependability of electronic equipment. There are by and large two classs: ( 1 ) anticipations based on single failure rates, and ( 2 ) demonstrated dependability based on operation of equipment over clip. Prediction methods are based on constituent informations from a assortment of beginnings: failure analysis, life trial informations, and device natural philosophies. For some computations ( e.g. military application ) MIL-HDBK-217 is used, which is considered to be the standard dependability anticipation method. A simple failure rate computation based on a individual life trial would follow equation 1. I »iˆ = failure rate. TDH = Total Device Hours = Number of units x hours under emphasis. AF = Acceleration factor, Since dependability informations can be accumulated from a figure of different life trials with several different failure mechanisms, a comprehensive failure rate is desired. The failure rate computation can be complicated if there are more than one failure mechanisms in a life trial, since the failure mechanisms are thermally activated at different rates. Equation 1 histories for these conditions and includes a statistical factor to obtain the assurance degree for the resulting failure rate where, I » = failure rate in FITs ( Number fails in 109 device hours ) I? = Number of distinguishable possible failure mechanisms K = Number of life trials being combined eleven = Number of failures for a given failure mechanism I = 1, 2, †¦ I? TDHj = Total device hours of trial clip for life trial J, J = 1, 2, †¦ K AFij = Acceleration factor for appropriate failure mechanism, I = 1, 2, †¦ K M = I §2 ( I ± , 2r +2 ) / 2 where, I §2 = qi square factor for 2r + 2 grades of freedom R = entire figure of failures ( I? xi ) I ± = hazard associated with CL between 0 and 1.2.2 SOLDER PASTERole Of Solder Paste In ReflowingSolder paste is a combination mixture of a flux composing and a extremely grinded, powdered solder metal metal that is usually used in the electronics industry to soldering procedures. And besides it is call as a attachment medium between the device interconnectedness characteristics and the PCB itself. The constituents of a solder paste are specially designed for first-class printing and reflow features. In normal instance of the surface saddle horse soldering procedure involves puting the substrate and a little sum of solder paste in a printed circuit board. After that the system will be heated until the solder reflows, forms an electrical connexion between the solder tablet and the electrical contact of electronics portion. After this reflow finished it forms both an electrical and mechanical connexion between the electronics constituents and the printed circuit board.Selection Criteria Of A Solder PasteChoice of a solder paste is really of import factor for reflowing procedure, dependability & A ; its quality. The undermentioned factors are considerable for a good solder paste [ 6 ] . The size of the solder metal atoms which are in the solder paste The inclination to organize nothingnesss The belongingss of the flux medium of the solder paste Alpha atom emanation rate The design of the stencil to be used for publishing Thermal belongingss of the solder paste Electrical belongingss of the solder pasteChapter 03MATERIALS AND EXPERIMENT METHODOLOGY3.1SOLDER PasteThe inside informations of solder paste used in the experiment are given in the undermentioned tabular arrayPCB noAlloy1 & A ; 2 Sn95.5Ag4Cu0.5 3 & A ; 4 Sn42Bi57Ag1 Table 3.1. types of solder paste used in experiment For this undertaking all above solder paste should be in a container with appropriate labelling and designation on it to separate it from the Tin – lead solder paste. The solder paste should be stored in a icebox between 35 – 45F. and should be allowed to come room temperature for minimal four hours before making the solder paste printing. Once it has finished the utilizing solder paste must replace to the icebox since it can non be at room temperature over 24 hours. The self life of the lead free solder pastes may be cut downing from the typical six month. The above guidelines are purely followed in this undertaking. Because it is non merely for warrant the quality of solder paste but besides a good manner to cut down the mistakes that may impact the concluding consequences of the undertaking.3.2 SOLDER PASTE PrintingImportant of Solder Paste PrintingSurface mount engineering ( SMT ) is used extensively in the electronics industry. Surface saddle horse constituents are potentially more dependable merchandises can be designed and manufactured utilizing the SMT. The solder paste stencil publishing procedure is really critical and of import measure in the surface saddle horse manufacting procedure. Most of all the bonding defects are due to jobs covering with the showing procedure. Stencil printing procedures have major cautiousnesss in operation and put up stairss. When we are supervising these factors carefully we can minimise the defects. The chief intent of publishing solder paste on PCB is to provide solder metal to solder joint to rectify sum. That merely publish must be aligned right and can acquire a perfect constituent arrangement.Printing Procedure ParametersSome of the undermentioned parametric quantities are really of import to publishing procedure. Stencil Stencils are utilizing for the solder paste slip easy off the aperture edges and thereby secures a unvarying print. For this procedure we utilizing electro formed stencils. Because of these stencils have really shape border and somewhat conelike. By and large a stencil is mading from cuppa or Ni. ENVIRONMENTAL Dust and soil from the air that will make the PCBs and stencils can be defects hapless wet ability in the reflow bonding procedure. So PCBs should be stored in certain bundles and cleaned before usage. SOLDER PASTE Solder paste characterise must be controlled to accomplish a maximal production consequences. Some of the factors are given below [ 12 ] . Percentage of metal Viscosity Slump Solder balls Flux activity working life and shelf lifeSolder Paste Printing Equipment and ProcessStencil printing parametric quantities are really of import factors in publishing procedures to accomplish a best output. The undermentioned parametric quantities must be proctors and controlled in a printing procedure. Squeegee force per unit area = 8kg Squeegee speed = 20 mm/s Separation speed = 100 % Printing spread = 0.0 millimeter These factors and bound can be adjust for our undertaking intent Figure 3.1 DEK 260 stencil printing machine The DEK 260 stencil printing machine is used to publish solder paste on the circuit board. This DEK 260 stencil printing machine has two chief maps. Registers the place of the merchandise screen with in the print caput Positioning the circuit board below the stencil, to cook for the print rhythm. The boards to be print are supported on magnetic tooling and held by vacuity caps arranged on the home base to vouch the board steady during the printing on to the board. The first measure of the experiment is to make the solder paste publishing on to the board.Figure 3.2 Stencil printing by manusIn this undertaking unable to acquire metal stencil, so circuit boards are printed by manus, below process followed to publish PCB Put weights onto the stencil to repair it turn over the squeegee over the stencil solder paste presses through the aperture onto PCB separate stencil Two circuit boards are printed with solder paste for each solder paste types. Wholly 4 circuit boards printed.Pick and PlaceComponent of PCB placed by choice and topographic point machine ( APS Gold-Place L20 ) . robotic weaponries are used to put surface-mount devices onto PCB. Pick and topographic point process as follow. pneumatic suction noses taken by caput of arm, so moved to feeder where the constituent is loaded. The suction nozzele picks it up utilizing vacuity, and moves to the arrangement location so centers the constituent with focus oning fingers. After justified aligned point, it places the constituent onto solder paste.Figure 3.3 APS Gold-Place L203.3 SOLDER PASTE REFLOWPROCESS & A ; PROFILEFigure 3.4 reflow ovenReflow procedure is really of import to accomplish a good dependable solder articulation. Novastar 2000 HT convectional reflow oven is used in research lab for the probe. When making the reflow procedure with lead free solder paste it has to be performed at a m inimal peak temperature of 150.It is by and large accepted that lead free solders requires a higher reflow temperature up to 230 – 240.reflow oven has six warming zones and chilling zone. ( Wu J.2000 ) Reflow profile will be impacting the dependability of a solder articulation. Because it is a major factor that influence the formation of the intermettallic beds in a solder articulation. Intermettalic bed is a critical portion of a solder articulation. An intermettalic bond thickness should be thin. Therefore a good reflow profile must bring forth solder bumps with a thin intermetallic layer.. ( Zhang RR.2001 )PREHEAT ZONEIn this zone indicates how the temperature is altering fast on the printed circuit board. The ramp-up rate is normally between 1-3 per second. If this rate exceeds there will be harm to constituents from thermic daze. Merely In this preheat zone the solder paste begins to vaporize. So if the rise rate is excessively low the vaporization of flux is non uncomplete. This will impact the quality of the solder articulation.THERMAL SOAK ZONEIt is besides called the flux activation zone. In this thermic soak zone it will take 60-120 seconds for remotion of solder paste an d activation of fluxes. Solder splatter and balling will be go on if the temperature is excessively high or excessively low. End of this thermic daze zone a thermic equilibrium will finish the full circuit board.REFLOW ZONEIn this reflow zone merely the maximal temperature will be reached. In this zone we have to see about the peak temperature that is the maximal allowable temperature of full procedure. It is really of import to supervise this maximal temperature exceeds the peak temperature in this zone. It may do harm to the internal dies of SMT constituents and a block to the growing of intermetalic bonds. we have to see the profile clip besides. If clip exceeds than the industries specification it besides affect the circuit board ‘s quality.Cooling ZoneIn the reflow procedure the last zone is chilling zone. A proper chilling inhabits extra intermetallic formation or thermic daze to the constituents. By and large the chilling zone temperature scope is 30 – 100. In this undertaking, the undermentioned temperature profiles were selected. This temperature profile is stranded reflow profile for lead free bonding. Zone 1 220 Zone 2 180 Zone 3 170 Zone 4 190 Zone5 233 Zone 6 233 Wholly 4 circuit boards were printed. Choosing of good reflow profile was non involves any defects or amendss in the printed circuit board.Figure 3.5 Reflow profileFigure 3.6 printed circuit board after reflowSET UP EVENT DETECTORFigure 3.7 Event sensorThe constructed PCB ‘s were connected with event sensor by thread informations overseas telegram. Ribbon overseas telegram addressed harmonizing to `Analysis tech STD series event sensors manual ‘ . pins 1 to 32 map as beginning terminus and pins 33 to 37 map as land terminus.Figure 3.8 Ribbon overseas telegram pin referenceTo obtain closed cringle circuit to supervise the behavior of PCB constituents, PCB boards 1, 2, 3 and 4 connected to impart 1,2,33 and 34 severally.Ribbon overseas telegramAfter connected thread overseas telegram with event sensor and environment chamber, channels are assigned in â€Å" WIN DATA LOG † package which supplied with event sensor. For this trial following scenes define for informations acquisition.Figure 3.9 set up trial informations in event sensor3.5 INVESTICATING RELIABILITY OF SOLDER JOINT UNDER VIBRATION CHAMERFigure 3.10 Design Environmental FS800-70SVIn this survey, PCB ‘s were used in Variable Frequency Vibration Test to analyze the dynamic response of PCB assembly subjected to random quiver burden. The PCB specimens were tested at different acceleration degrees to measure the solder articulation dependability subjected changing G-level quiver tonss ( G is the gravitative acceleration ) , severally. Vibration trials were accomplished by utilizing an electro dynamic Shaker ( Design Environmental FS800-70SV ) and event sensor. One accelerometer was used to find the dynamic response of the specimen, Daisy concatenation cringles were monitored at the same time by an Event Detector during quiver trial. Any opposition alteration transcending a preset threshold with minimal continuance of 200ns can be d etected by the Event Detector. When a cleft is initiated in the solder articulation during the quiver trial, the opposition will increase. The failure standards recommended by IPC – 785 criterion is defined as daisy concatenation opposition by thermic or mechanical transients or perturbations in the signifier of short continuance ( ~ 1 A µsec ) high opposition spikes ( & gt ; 300 a„ ¦ ) . During thermic alterations the solder articulations are capable to shear, non tensile, lading ; hence, fracture surfaces of fractured solder articulations slide relative to each other bring forthing the characteristic short continuance intermittent. Therefore, in this context, the practical definition of solder joint failure is the break of electrical continuity ( & gt ; 300 ohms ) for periods greater than 1 microsecond. Figure 3.11 PCB ‘s was mounted inside the Environment chamber in this mode. Figure 3.12 Above tabular array exemplifying trial program.Figure 3.13 Trial programFigure 3.14 graphs obtained from chamberChapter 4ConsequencePCB board Failure rate ( % ) Operation clip ( hours ) Dependability 1 24.0 5 0 2 63.0 13.04 0 3 1.6 0.3305 0.5893 4 2.5 0.5083 0.2806Table 4.1 dependability of solder pasteThe proving began with 1 GRMS. The intent of this to observe any gross issues in solder articulations, every bit good as with the informations acquisition system. No failures were detected at beginning, nevertheless, after 1.5GRMS an review revealed that both PCBs 3 and 4 were failed. Following, quiver degrees were stepped bit by bit to 6GRMS increases over the period of five hours PCB 1 got failed, In 13.04 hr ‘s period the chamber reached degree of about 14GRMS, staying PCB besides got failed. However, the failure mechanism was attributed to a quiver moving on the solder connexion particular to these parts and was straight related to thermic mistakes. Failure rate Time elapsed Above graph illustrating failure rate vs. Time elapsed for Sn42Bi57Ag1 Failure rate Time elapsed Above graph illustrating failure rate vs. Time elapsed for Sn95.5Ag4Cu0.5Chapter 5RESULT ANALYSISFrom dependability analysis sample 3 has maximum dependability and sample 2 has minimum dependability. Each sample was subjected to nominal supply current and opposition value in conformity with the design and public presentation specification. Respective trial samples continued to vibrate with some public presentation abnormalities observed. The aim of this experiment was to utilize HALT quiver to set up the relationship between the life of similar parts soldered with different solder composings. The consequences proved inconclusive for the primary intent of â€Å" Sn95.5Ag4Cu0.5 † versus â€Å" Sn42Bi57Ag1 † articulation random quiver trial. Both composings demonstrated weak public presentation and the consequences may propose that with regard to this brief random quiver trial, solder articulation dependability is different between the two composings. No samples were separated from the trial vehicle as a consequence of the quiver applied. However, the trial procedure revealed insight into HALT and suggested factors which can impact consequences when soldered constituents are being compared. First, Printed circuit board kineticss would be understood and controlled so that acceleration hot musca volitanss and nothings are made more equal in amplitude. A flexible PCB will debar and bring forth bending emphasiss suited for measuring emphasis on solder articulations. But with a flexible board acceleration uniformity become hard to command and do a comparing trial less nonsubjective. Second, HALT random quiver is a good methodological analysis for bring forthing multi-axis wide spectrum energy for PCBs and their constituents. ( Wu J.2000 ) The typical method to analyze the functionality of a PCB in a quiver environment is to verify the quiver transmissibility. Normally the transmissibility at any location of PCB should be less than a factor of 10, i.e. , 1 G input will non bring forth more than 10 G end product at any location of the PCB. To accomplish this end, two methods can be applied to the PCB design. One is to restrain the PCB tightly to the fixture, which can be realized by bettering the boundary conditions in the finite component analysis theoretical account. The other is to relocate heavy affiliated constituents of the PCB board to allow optimum locations ( i.e. , mass re-distribution ) . ( Wu J.2000 ) Lead free solder assemblies have quickly been promote in the micro-packaging development to forestall the environmental pollution, issues on the dependability has non been clearly solved. Several experiments have been conducted on the soundness of alternate lead free soldering technique such as Sn-Ag-Cu solder. During the bumping procedure, a considerable thermic distortion is occurred and the chemical features of solder and bed qualities are besides changed in agreement with the surface completing method such as ET ( electric Sn ) , ENEPIG ( electro less nickel, electro less Pd and submergence gold ) etc. The IMC ( intermetallic compound ) bed is formed in a micro-scale part between the solder and the surface completing stuff under high temperature adhering procedure. In the field of micro-packaging together with IMC bed, one of the most hard issues is to mensurate width interface beds in a solder articulations. Since the IMC beds have been estimated as the weakest subdivision in th e solder articulations, a accurate finding of mechanical belongingss in the country of this critical part may supply direct and enhanced information to understand the break behavior. aˆ? . ( Zhang RR.2001 ) stringency of mounting bolt of PCB reduced during experiment. Due to this consequence the PCB stated to vibrate freely. Applied quiver force was non shared uniformly. From finite component analysis alterations in stringency of mountin bolt can be realize.Chapter 6DecisionThe decisions ensuing from this work are:.Interactions between temperature and quiver were found important and therefore had influence on concluding consequence. Stencil printing by manus affect the solder joint dependability. Better apprehension gained about electronic assembly behaviors when subjected to quiver. Gained cognition about electronic assembly procedure and how it is act uponing in solder articulation dependability. Gained good experience in managing event sensor and environmental proving chamber.Chapter 7FUTURE WORKSIn this undertaking investigated the consequence of quiver of solder articulation dependability in electronic assembly. For this probe two different types solder paste used, eventually all specimens were tested in environmental Chamber. In this undertaking when making quiver trial informations acquired by event sensor is non accurate value. From informations obtained from event sensor does non give proper analytical consequence. In sing about the hereafter works of this undertaking can be expand based on acquirable informations type, every bit good as finite component analysis because dependability of a solder articulation depends on assorted environmental factors, so result analysis will be more accurate and stand with more international criterions.

Free Essays on Casino Dispute

â€Å"Casino Dispute† If you live in the United States of America, does the constitution apply to everyone or just a certain race or group of people? I think that if you live here you must follow the same rules and regulations as every other American citizen or pay the consequences. The Native American people are building casinos on their reservations and are disputing whether or not they have to pay taxes like everyone else. I say they should because there is a popular statement that says, †You only have to do two things in life, pay taxes and die.† And just because our ancestors put them through hard times and killed off a lot of the Indians when they arrived in America doesn’t mean we owe them anything in the 21st century. I think the states that are holding these reservations with the casinos on them should have the right to tax them just as they do the African Americans, Hispanics, Caucasians or whatever race you are. We put the African Americans through a lot more hardships than we ever did the Natives and I strongly disagree with them not having to pay taxes like the rest of us! I am eighteen years old, and I was paying taxes before I became an adult. I know that is their land the government set aside for them to go about their lives on, but they are not even responsible enough to hold down a job. Because the statistics show that 50% of them are unemployed and 73% of them that do work make less than 9,000 a year. To me that is ridiculous because I am responsible enough to get up every morning, go to school and then to work. If they can’t find a job on the reservations getting paid more than that I would find a job with the rest of the population. I would have no problem with them not being taxed if it was on the reservation and only Indians that lived there could gamble, but they are doing this to attract people from all over and make 100% profit. I do think this is a positive thing for their community ... Free Essays on Casino Dispute Free Essays on Casino Dispute â€Å"Casino Dispute† If you live in the United States of America, does the constitution apply to everyone or just a certain race or group of people? I think that if you live here you must follow the same rules and regulations as every other American citizen or pay the consequences. The Native American people are building casinos on their reservations and are disputing whether or not they have to pay taxes like everyone else. I say they should because there is a popular statement that says, †You only have to do two things in life, pay taxes and die.† And just because our ancestors put them through hard times and killed off a lot of the Indians when they arrived in America doesn’t mean we owe them anything in the 21st century. I think the states that are holding these reservations with the casinos on them should have the right to tax them just as they do the African Americans, Hispanics, Caucasians or whatever race you are. We put the African Americans through a lot more hardships than we ever did the Natives and I strongly disagree with them not having to pay taxes like the rest of us! I am eighteen years old, and I was paying taxes before I became an adult. I know that is their land the government set aside for them to go about their lives on, but they are not even responsible enough to hold down a job. Because the statistics show that 50% of them are unemployed and 73% of them that do work make less than 9,000 a year. To me that is ridiculous because I am responsible enough to get up every morning, go to school and then to work. If they can’t find a job on the reservations getting paid more than that I would find a job with the rest of the population. I would have no problem with them not being taxed if it was on the reservation and only Indians that lived there could gamble, but they are doing this to attract people from all over and make 100% profit. I do think this is a positive thing for their community ...

How to Meet People in College

How to Meet People in College Knowing how to meet people in college can be more challenging than you might have expected. There are tons of students, yes, but it can be hard to make individual connections in the crowds. If youre not sure where to start, consider one of these ten ideas: Join a club. You dont need to know anyone in the club to join; you just need to have a general interest about the clubs activities and mission. Find a club that interests you and head to a meeting even if its the middle of the semester. Join an intramural sports team. Intramurals can be one of the best features of being in school. Youll get some exercise in, learn some great athletic skills, and of course! make some great friends in the process. Volunteer on or off campus. Volunteering can be an easy way to meet people. If you find a volunteer program or group that shares your values, you can make a difference in your community while also making some personal connections with people just like you. Win-win! Attend a religious service on-campus. Religious communities can be like a home away from home. Find a service you like and the relationships will naturally bloom. Get an on-campus job. One of the easiest ways to meet folks is to get an on-campus job that involves interacting with lots of people. Whether its making coffees in a campus coffee shop or delivering mail, working with others is a great way to get to know a lot of people. Get involved with a leadership opportunity. Being shy or an introvert doesnt mean you dont have strong leadership skills. Whether youre running for student government or just volunteering to organize a program for your club, serving in a leadership role can allow you to connect with others. Start a study group. While the main goal of a study group is to focus on academics, theres also an important social side. Find a few people who you think would work well in a study group and see if everyone wants to help each other out. Work for the campus newspaper. Whether your campus produces a daily newspaper or a weekly one, joining the staff can be a great way to meet other people. Youll not only connect with your fellow staff members, but youll also connect with all sorts of other folks doing interviews and research. Work for the campus yearbook. Just like the newspaper, the campus yearbook can be a great way to connect. Youll meet tons of folks while working hard to document all that happ ens during your time in school. Start your own club or organization! it may sound silly or even intimidating at first, but starting your own club or organization can be a great way to meet other people. And even if only a few folks show up for your first meeting, thats still a victory. Youll have found a few people you share something in common with and who, ideally, you can get to know a little better.

Relational Database Assignment Example | Topics and Well Written Essays - 750 words

Relational Database - Assignment Example This assists the user in matching the data with the help of common characteristics contained in the data set including the relation or tables. Relationships play a role in making the data more organized and manageable. This helps the user in perceiving the real concept of design of the database. This also increases the integrity of data through proper arrangement of the data which is logically related into distinct relations. Thinking about the efficiency of database and relationships is an essential component of the normalization process (yaldex.com, n.d.). A relationship is a prime component of the relational database as it develops an association between the logically related pair of tables. The data contained by each of the two tables is the bonding agent between the pair of tables. Relationship if properly defined promotes relationship-level integrity, that in turn ensures the reliability and strength of the relationship (eTutorials, 2012). In addition to that, relationships mak e it possible for the user to perform algebraic operations upon the tables. Division of the elements of a data into the related tables is one of the most challenging tasks of designing a relational database. Once the user is all set to begin work with the data, the user depends upon the relationships among individual tables so that the data can be pulled together in purposeful ways. For example, information about a particular order is of no use if the user does not know the customer who has placed it. Nevertheless, the customer and the information about his/her order are not stored in the same table. Instead of this, the user stores the customer data and the order in two tables that are interrelated. The very relationship between the tables is used to view both the order and the customer data simultaneously. Relationships are the cornerstone when the normalized tables play the role of foundations of the relational database Relationships also help prevent the redundant data in a rela tional database (Microsoft Support, 2011). Defining Relationships between Two Tables A very essential characteristic of the database design is the use of relationships between tables. Defining relationships between tables is very essential for efficient working of the system. â€Å"Relationships between tables are often missing for performance reasons† (Olson, 2009, p. 111). Relationships between two tables are defined through the database system which depends upon matching the values contained in the two tables. When matching values are located, the database system retrieves data from the two tables so that a virtual record can be established. For example, let’s suppose an individual wants to view all the perfumes made by a certain brand. In this example, the database system would locate matching values between the tables of Perfumes and Brands. It is noteworthy here that in a vast majority of cases, the record which results is dynamic that essentially means that chan ges which are made to the virtual record normally identify the path to the underlying table. The matching values that the database system finds include the foreign and primary key values. It is not necessary for a relational model to base the relationship upon a primary key. The user can make use of any candidate key from the table. However, the standard practice requires the use of primary key only. When the primary key of one table is put into another table, a foreign key is formed. All a user needs to do is add the field of the primary key as a foreign key to the

Summary of a book chapter Assignment Example | Topics and Well Written Essays - 500 words

Summary of a book chapter - Assignment Example The chapter focuses on the value system of terrorists and states that terrorists believe that they are fighting against enemy who lack traits and characteristics of human beings. Terrorist even believe that they are elite members of the society and are victims and they chose terrorism as an involuntary response (Combs, 2012, p.56). They even believe that the crimes they commit such as murdering innocent people is a moral act. They even believe that if their victims are closely associated with the enemy then they are even enemies. There are certain common characteristics that all terrorists share. These characteristics include high dedication towards the cause and all of them indulge in a brave act since they face the threat of being harmed (Combs, 2012, p.65). All terrorists lack emotions of regret as well as shame and that is why they kill people. They are very intelligent as they have to collect and analyze information and are involved in sophisticated activities such as living and flying in first class hotels and airlines. They are highly educated as they are able to communicate in various languages such as English language. Individuals become terrorists because they believe that they are the victims and are fighting evil. Joining terrorist groups even provide individuals with a sense of belongingness (Combs, 2012, p.68). They believe that indulging in acts of terrorism is a way to attain revenge against those who have done wrong to people they are associated with. Terrorists in the past were motivated by the aim of attaining social liberty, but now their aim has become quite political. Terrorists in the 21st century are quite away from reality and are quite irrational and that is why they prefer being recognized as prisoners of war (Combs, 2012, p.71). A major reason that drives terrorist activities in the 21st century is that