The ozone Layer and the greenhouse effect Essay Example for Free

The ozone Layer and the greenhouse effect Essay Ozone, an allotrope of oxygen is present in the atmosphere in only tiny amounts. It is found almost entirely in the stratosphere. It is vital for our survival as it filters out harmful ultraviolet radiation. However if ozone reaches ground level it is harmful to human health. It weakens the bodys immune system and attacks lung tissue. Ozone is extremely reactive and reacts with other gases very quickly but there are also reactions that are producing ozone and without human intervention this ozone would be in a steady state equilibrium. The natural reactions that involve ozone are: In this reaction hindicates the photon of ultraviolet radiation that is absorbed. Reaction 2 is the one that produces the ozone and reaction 4 is the one that destroys it. The is also another reaction that destroys ozone. 5. O3 + h O + O2 This is the reaction that is responsible for the screening effect of ozone, since it absorbs ultraviolet radiation. Chemists are able to calculate the concentration of ozone that should be in the stratosphere by working out how fast the rate of making and destroying occur, but when they actually measured the concentration it was a great deal less than expected. This tells us that there must be something else that is destroying the ozone other that the natural reactions. There are other radicals in the stratosphere that can react with ozone. An example of these is the chlorine atom and the bromine atom. Chloromethane and bromomethane can get into the stratosphere naturally from the oceans and by burning of coal and vegetation. Most of the chloromethane and bromomethane react in the troposphere but some manage to get onto the stratosphere. Once in the stratosphere the chloromethane splits up due to solar radiation and then the chlorine atom is able to react with ozone. The reaction occurs in a catalytic cycle: 1. Cl + O3 ClO + O2 The ClO is another radical able to react again 2. ClO + O Cl + O2 So now there are two reaction competing to destroy ozone 1. Cl + O3 ClO + O2 2. O + O3 O2 + O2 In the stratosphere there is a much lower concentration of Cl atom compared to O atoms, so it would seem that the reaction with Cl would be insignificant but chemists have measured the rate of reaction of Cl with ozone and have found it to be 1500 faster than the rate of reaction with O atoms. Also because Cl atoms are regenerated in a catalytic cycle they play a large part in removing ozone. In the 1930s scientist Thomas Midgley demonstrated a new refrigerant. He inhaled a lungful of dichlorodifluoromethane (CCl2F2) and used it to blow out a candle. He was showing two of the properties of the gas; its lack of toxicity and lack of flammability. CCl2F2 belongs to family known as chlorofluorocarbons (CFCs), which contain chlorine, fluorine and carbon. Some other useful things about CFCs is there low boiling points and low reactivity. CFCs seemed to be the perfect answer to many problems. They had many uses such as propellant in aerosols, refrigerants, blowing agents for making expanded plastics and as cleaning solvents. In the troposphere they remain unreactive and there estimated lifetime is about 100 years. This gives them plenty of time to reach the stratosphere where they are no longer unreactive. They are split up by the solar radiation giving out the fluorine and chlorine to react in the stratosphere destroying ozone. In 1984 a group of British scientists discovered a hole in the ozone layer over Antarctica due to CFCs. Due to the scientists finding this hole there has been a worldwide ban on using CFCs since 1990. A replacement to CFCs are hydrochlorofluorocarbons (HCFCs) and hydroflurocarbons (HFCs). The difference with these is that they contain a C-H bond which is quickly broken down in the troposphere before they have time to reach to stratosphere. Unfortunately they are not the perfect solution as they contribute to global warming. The Greenhouse effect occurs in the. Without it the Earth would be uninhabited. By trapping the Suns radiation the atmosphere keeps the temperature high enough to support life. Greenhouse gases are gases that trap the Suns radiation. Burning fossil fuels, therefore releasing CO2 can make more greenhouse gases effectively warming the Earth. The Sun radiates energy mainly in the ultraviolet and visible. The part that is absorbed helps to heat the Earth, and the Earth the radiates energy back into space. Some of the energy radiated is absorbed by the troposphere heat the Earth. This is known as the greenhouse effect. If we release to many greenhouse gases this will in turn heat the Earth more causing sea levels to rise as the ice caps melt. The rise in sea level will leave low-lying coastal place to disappear under-water. Tom Harbud 01/03/2001 Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section.

teens with hiv taking more risks :: essays research papers

Teenagers infected with HIV are more likely to engage in risky sex and drug use since the introduction of powerful medicines that effectively keep AIDS at bay, a new study finds. The trend, which began surfacing after highly active antiretroviral therapies (HAART) were introduced in 1996, points to the need for targeted interventions to reduce risky behavior and improve quality of life for those in this group, the researchers noted. Roughly a quarter of the 40,000 new HIV infections in the United States each year occur in people under the age of 21, according to the federal Centers for Disease Control and Prevention. "Young people, post-HAART, are engaging in more unprotected sex and engaging in more substance abuse, and are more emotionally distressed and have a lower quality of life," said lead researcher Marguerita Lightfoot, an assistant research psychologist at the University of California, Los Angeles' Center for Community Health. This finding was surprising, Lightfoot added. "I had a hypothesis that the young people who are taking HAART would be healthier, because they had more hope, they were living longer. And I was surprised that that wasn't the case." In the study, Lightfoot and her colleagues compared behaviors among 349 teens with HIV from Los Angeles, San Francisco, New York City and Miami from 1994 to 1996, with 175 teens with HIV in the same cities from 1999 to 2000. The two groups did not include the same people, but they were a similar mix of sex, age, race and ethnicity, as well as socioeconomic factors, according to the report in the March issue of the American Journal of Health Behavior. The researchers found the post-HAART group was almost two times more likely to have had unprotected sex. The post-HAART teens had almost twice the number of sex partners, compared with pre-HAART teens. And post-HAART teens were more likely to have a sexual partner who used injected drugs. In addition, the post-HAART group was diagnosed with HIV at a younger age and was in worse health than the pre-HAART group, Lightfoot's team found. Lightfoot said there are a number of reasons for these findings. She noted the powerful drug regimen isn't perfect. "There are increased expectations for HAART," Lightfoot said. "But not everyone is successful on HAART." Lightfoot also noted that teens infected with HIV are more apt to be involved with the juvenile justice system and spend time in jail. "Maybe it says something about the kind of young people who are more likely to be infected with HIV.

Final Nerrative Essay

He became difficult and refused to listen to Our mother. He would stroll the the streets all night and routinely come back home with items we suspect were stolen. My parents had always pondered upon and discussed the consequences of leaving us alone, without the guidance and support of both a mother and father. But because of our financial situation, my father needed to make the sacrifice. We all needed to sacrifice something. Subsequently, the behavior of my brother got worse over time and finally hit rock bottom one cold night. One Friday night approximately at 9 p. . , I was returning from school, about a block away from my house, I spotted a group of kids beating up a person. As I got closer, I recognized the unconscious body of my brother. Me being only 13 at the time, I launched myself with the greatest possible might at these bullies, which were in their twenties. Recall about 20 seconds of the fight, as I was getting stomped in my face, lying on the wet ground. To this day, I can still smell the dirt, water, blood, and leaves of that particular bush that grows around the rivers in that region of Mexico.The next day woke up in a hospital, and my first thought was about my brother. Was he well? Where was he? I ignored my head covered in bandages and the pain of my broken arm. Not even the fact that my dad flew from Los Angles and was there by my side. My heart began to fill with anger towards the man beside me, for failing to be there for us, and leaving his wife and children alone for months. When the nurse finally rolled my brother in on a squeaky hospital bed into the room, the whole family burst into tears the moment my brother and I embraced. Those were the tears of enormous relief that we were both alive.Up to this day, it has been the only time I have seen my dad cry. That day, all of us cried as a family in that cold blue pine smelling hospital room. During the following weeks of our recovery our father stayed in Mexico with us. About 3 weeks afte r this ordeal, we went back with the local police to the area where my brother and were attacked. The eerie feeling embraced us, as we walked down the block to that area. I will never forget the look on my father's face, as he looked at the scattered broken branches and our blood on he concrete floor, where we laid that night.For my father, the realization of his sons coming close to losing their lives finally struck him, he broke down. The police never found out what gang was responsible for the attack; though, still have a feeling that my brother knew some of them, but I never pushed the issue upon him after that. My parents discussed the option of sending my brother to a military school for kids who are on the wrong path in life, but a funny thing occurred. Once my father was with us fulfillment, my brother Joe completely changed, it was as a light bulb went off. Never again he got into trouble.For the sake of the family, my parents made a decision to move back to California. We sold our house in Mexico and within months, the whole family moved back to Los Angles. My brother continued to behave, as he confidently found his positive path. It ultimately took the presence of my father to turn him around. Frequently hear arguments in single parent households, that a father is not needed for happiness and stability in the family. In some instances that might be true, however, when it comes to our family, our father is the glue hat has kept us together to this day.

Design of Compact Dual-Band Microstrip Patch Antenna

Design of Compact Dual-Band Microstrip Patch Antenna for GPSK-PCS Operation Ho-yong Kim', Yong-nn Lee, Chung-ho Won, Hong-min Lcc Department of Electronics [email  protected] Univerrily hi-Dong, Yeongtong-Cu, Suwon-Si, Kyonggi-do, Korea email: [email  protected] com lnlraduetion In recent years, with the advance o f technology, the demand for an antenna operating a1 mutibands i s increasing rapidly. Such as GPS and K-PCS, The multi-hand antennas with one feeding pon use the multiple resonance technolagy[l] such antennal are difficult lo provide a good polarization efficiency for GPS signal reception. So the integrated GPSIK-PCS dual-band antenna using two feeding pan has been proposed in this paper. Referenced dual-band antenna using two feeding pon has matched poiariration of integrated system. [2] but it has large size. Proposed antenna uses miniafurizalion technique that is to insect ilits. This technique is to increase elecVlcal surface length by slits. [3-5] Operating frequency o f proposed Bntenna is greatly lowered by slit^. Meander line patch and square ring patch with four diu o f proposed antenna are about 70% and 50% ofreferenced antenna size. The proposed antenna composed of a low-profile cylindrical monopole with a top-loaded meander line patch for K-PCS Operation, and a comer-truncated square-ring microstrip patch antenna with four-slits for GPS ooeration. Pmposed Antenna Design The geometry and design parameter of the proposed antenna for compact GPSIK-PCS operation i s presented in Figure I. The proposed antenna has the common ground plane, but i s fed by separate feeding pon. The antenns for GPS-hand i s realized by using a corner-truncated square-ring microstrip patch with four slits. The outer side length and inner ride length are40mm(L,)and IZmm(&) ~ ~ p % t i d printed on a rubrtrale o f thickness 1. 6mm(h) and y, relative peminiviry (e, :4. 4). The middle ofthe substrate is removed for inner rectangular d i t area ( b x b ) of patch. Feed position for right-hand circularly polarized (RHCP) wave operation is placed along x-axis. and the distance of the probe feed away fram the patch center i s denoted as 6 . 6 m m ( / ) . The four-rlitr at the comers are of equal length I3. 5mm(S)and width Imm(w). Fig 2(a) shows simulated reNm loss of the proposed anlenna for GPS receiving antenna with various d i t lengths(S). It i s noted that the reSonant frequency rapidly lowered with increasingdesign parameter(S). In f h i ~ way, the excited surface current paths are lengthened in the propo~ed designs, and the operating frequency is greatly lowered. 0-7803-8302-8/04/$20. 00 IEEE 3529 02004 Also, the shorted meander line patch antenna with low-profile cylindrical monopole top is loaded at the center of square ring patch for K-PCS operation. For brbadband characteristic, cylindrical monopole has a large diameter of 6. 2mm(d,) and l e n ~ h 10. 7mm(h2). The eander line patch has a ride lengh Z l m m ( p ) and is connected to the common ground by two same shorting posh, which have a diameter of 2. 2mm(d2). By varying ofthe shorting ports diameter(d2), good impedance matching can easily be obtained. Figure 2(b) shows simulated retum loss for the p r a p ~ ~ e d K-PCS antenna with various slit lengthr(m,) of meander line patch. Meander line patch size can be reduced by increasing inserted slit length. Becaus e of the antenna for K-PCS operation interfere the axial mtio of GPS receiving antenna, the miniatufimion of GPS antenna is limited. According to the experiment, the patch size of GPS antenna for circular polarized operation must he over about twice the size of KPCS antenna with meander line suunurc. In the proposed designs, the bandwidth of3-dB axial mtio is about 13 MHz, which is much larger than that required for GPS operation at 1575 MHz. The measured axial ratio ofthe antenna for GPS operation i s presented in Figure 3. Figure 4 shows measured re† 101 of proposed antenna. The impedance bandwidths (. lOdB retum larr) are about lZOMH~(1744MHr-1864MH~)far K-PCS band and 60MHr (IS46MHr-1606MHz) for GPS-band. The isolation between the two feeding pons of the PCS and GPS elemenls is less than -17dB. Measured radiation panems of the proposed antenna at l8OOMHz and ISROMHz are presented in Figure 5 and 6, respectively. The K-PCS antenna radiation panem at IROOMHz shows a monopole radiation panem, 10 this fype of antenna is suitable for applications on a vehicular communication system. For the GPS anfenna at ISROMHz, good broadside band radiation panem is obtained. Far K-PCS operation the measured pea* antenna gains is about 2. 4dBi and t h c gain variations are within O. JdBi, for GPS operation the measured peak antenna gains is about 7. dBi and the vanations of gain does not exist. Conclusion Proposed antenna has a integrated slmcturc of microitrip patch antenna with two feeds for dual-band oprmtion(GPSiK-PCS). A low-profile cylindrical monopole with a shorted meander line patch i s loaded for K-PCS operation, which rhowr a linearly polarized monopole patkm with broadband characterirlic. Th e radiating clement for GPS operation is a novel square-ring microstip path with truncated comers with four slits, which provide circularly polarized braadrids radiation panemr. size reduction of proposed antenna is achieved by using slits. Meander line patch and square ring patch with four . lib of proposed antenna are about 70% and SO% of referenced antenna sire. As the proposed antenna has a compact size for dual band operation, it will be suitable for practical vehicular mobile communication antenna applications. R&E†Ce [I] R. Kronberger, H. Lindenmcier, L. Reiter, J. Hapf, † Multi hand planar Invencd-F C r a Antenna for Mobile Phone andGPS,†2714p-Z717p,AP confer. 1999 3530 [2] I. Y. Wu and K. L. Wong, â€Å"Two inlegraled stacked shorted patchantennas for DCSiGPS operations,† Micra wave Opt. Techno1 . Len. , Vol. 30. July, 2001. I31 S. Reed, L. Desclar, C. Terref, and S. Toutain, â€Å"Patch Antenna Size Reduction By Means Oflnductive Slots,† Micro wave Opt. Teehnol. Len. ,Vol29. Apri, 2001. 1 [41 J. Y. Wu and K. L. Wong, â€Å"Single-feed Square-ring Microstip Antenna wilh lruncated comers for Compact ~ircularpolarization Operation,† Electronics lea. , Vol. 34, May,1998. [ 5 ] W. S. Chen, C. K. Wu, and K. L. wong. I' Novel Compact Circularly polarized Square Microstrip Antennq† IEEE Trans. ,Antennas Propagat. , Vol. 49, March, 2001, L, = 40mm, L, = 12mm, S = 13. 5mm, t = 5. 74mm. IY = I n † f = 6. 6†³. p = Zlmnr, m, =ZOmm, ml =3. mm, d) = 6. 2mm, d* = 2. 2†³. d, =9. 3mm h, = 1. 6mm. h2 =10. 7mm Fib. 1. Geomelly and dimiiiimi ofthe pmpanrd a n t m i l for CPSIK-PCS operation. (a) The variation against parameter S (b) The variation againsl parmnster m, Fig. 2. Simulated return loss wilh v~riour ImgthsiS) nnd vsriour slit lengthsim,). slit 3531 I E 4 , d B ! -2 1. 560 1. 565 1. 570 1. 575 1. 580 .† -15 FrequanollGHz , I . 1. 5 2. 0 ~r4†³enwffi~ 2. 5 Fig. 3. The measured arid ratio. Fig 1 Measured r t b m loss of antenna. . (a) x-2 plane @) x-Y plane Fig 6. Measured radiation panem for GPS operation; f=1580MHz 3532

Can Undocumented Immigrants Go to College

Can Undocumented Immigrants Go to College SAT / ACT Prep Online Guides and Tips During my undergraduate years at Stanford and in my first job after graduation, I counseled a number of undocumented high school students. Many undocumented students incorrectly assume that they’re not allowed to go to college. While there are additional barriers that make pursuing a college education more difficult, I’m proud to say that I know multiple undocumented immigrants who are now graduates from prestigious universities. In this article, I’ll detail the rules and obstacles for undocumented students who pursue higher education. College Admission Policies for Undocumented Immigrants There is no federal law that prohibits the admission of undocumented immigrants to either public or private US colleges. However, institutional policies can vary, and some states have placed restrictions on undocumented students from attending in-state postsecondary institutions. The Georgia Board of Regents banned undocumented students from attending the top 5 state-funded colleges in Georgia. Also, Alabama and South Carolina prohibit undocumented students from enrolling at any public postsecondary institution. Despite these prohibitions, the majority of US colleges remain open to undocumented students. Many colleges are becoming increasingly vocal and open about their support for undocumented immigrant students. This year, Rutgers University-Newark held a college admissions fair for undocumented students. Furthermore, top colleges like Stanford, Dartmouth, Duke, and the University of Chicago have stated that they welcome the applications of undocumented students and have undocumented students enrolled. Regardless of citizenship status, you can be a college grad! However, even though undocumented immigrants can be admitted to most of the nation's colleges, financial obstacles make attending much more difficult. Financial Issues for Undocumented Immigrants Undoubtedly, the biggest hurdles for undocumented students going to college are financial. Federal Aid Undocumented students can't legally receive any federally funded aid, including loans, grants, scholarships, or work-study money. Most students who need financial assistance to attend college fill out a FAFSA, the Free Application for Federal Student Aid and are given federal grants and loans based on their expected family contribution. Undocumented students do not have this option because they're ineligible for all forms of federal aid. State Aid and In-State Tuition Many states treat undocumented students like foreign students. In these states, undocumented immigrants are ineligible for state aid and the lower in-state tuition charged to residents at state institutions. Arizona, Georgia, and Indiana specifically prohibit in-state tuition rates for undocumented students. States That Offer In-State Tuition Some states, though, have passed laws that enable undocumented students to pay in-state tuition if they meet certain conditions, and trends seem to indicate that more states will offer in-state tuition to undocumented students in the future. Currently, 16 states have laws allowing undocumented immigrants to pay in-state tuition provided they meet certain requirements: California, Colorado, Connecticut, Florida, Illinois, Kansas, Maryland, Minnesota, Nebraska, New Jersey, New Mexico, New York, Oregon, Texas, Utah, and Washington. For example, California has a state law known as AB 540. Undocumented students qualify for in-state tuition if they attend a California high school for 3 years, graduate from a California high school, and fill out an affidavit that says they will apply for US residency as soon as possible. Additionally, Oklahoma and Rhode Island allow in-state tuition rates for undocumented students through Board of Regents' decisions. And, in 2013, the University of Hawaii's and the University of Michigan's Board of Regents adopted policies for undocumented students to have access to in-state tuition at those colleges. States That Give Aid Presently, California, Minnesota, New Mexico, Texas, and Washington allow undocumented students to receive state aid. Private Scholarships Most private scholarships require applicants to be US citizens or legal residents. However, there are some scholarships that are open to undocumented immigrants and an increasing number of scholarships are specifically for undocumented students. For more information regarding private scholarships for undocumented students, check out: Golden Door Scholars TheDream.US MALDEF Scholarship Resources QuestBridge Becas Univision Scholarship Furthermore, you can review this scholarship guide for undocumented students. In addition to these scholarships, some private colleges, including NYU, grant scholarships or other aid to undocumented students. How to Address Your Citizenship on Your Application If you're an undocumented student, don't lie or misrepresent your citizenship status on your application. Leave your social security number blank. Don't put in an Individual Taxpayer Identification Number, Alien number, or any other number. For the University of California, undocumented students should select "No Selection" for their country of citizenship. In your application essay, absolutely, feel free to address your immigration status and situation. Colleges want to hear about obstacles that you've had to overcome, but don't let those obstacles define you. The purpose of the application essay is for the school to get to know you and get a better sense of how you could possibly contribute to the college's community. Focus on your accomplishments and what makes you unique as an individual. The Federal Education and Privacy Act (FERPA) protects the privacy of student records at all educational institutions. Whatever you write in your essay or talk about with admissions or financial aid counselors will not be reported. Additional Advice for Undocumented Immigrants State and federal laws change all the time, especially since immigration is such a politically charged issue. Educate yourself about current state and federal laws regarding tuition and aid rules for undocumented students. The two federal laws you should be aware of are DACA and the DREAM Act. If you are DACA eligible, you can get a work permit and be freed from the fear of deportation for at least 2 years. Unfortunately, you still won't be eligible for federal financial aid. The DREAM Act has not been passed and has undergone numerous changes since it was first proposed in 2001. However, if it ever passes, it could have a profound impact on higher education access for undocumented students. Also, if it does pass, you'll be on a path to citizenship if you attend college. If you have a good relationship with your counselor, talk with him or her about your options and get guidance. Remember, though, you do not have to reveal your immigration status or your parents' to any school personnel, and they can't ask you about it. Make yourself competitive for college admission. Get good grades, take college prep classes, do well on your standardized tests, and try to participate in extracurricular activities. Because your immigration status may limit your options, you should do what you can to give yourself the most opportunities. Additionally, some of the scholarships that you're eligible for are more likely to go to high achieving students. Contact admissions officers and financial aid counselors at the schools you're interested in attending. Typically, they'll try to be helpful and they won't report your immigration status. They can inform you of their financial aid options for undocumented students and let you know how to fill out the school's application, specifically in regards to questions about citizenship and residency. Do research on colleges that offer support for undocumented students. For example, UCLA and UC Berkeley have support programs that provide services and advice for undocumented students. Finally, look at the Repository of Resources For Undocumented Students. It has information about state laws. Also, it has information about scholarships you may be eligible for and organizations that can offer you support and advice. While you may have more hurdles to overcome, graduating from college is possible and will likely give you a better life and future. What's Next? If you're an undocumented student, there may be additional factors to consider, but you should review this post on how to choose a college. Also, you'll want to know the best college search websites. Lastly, if you're wondering how to make yourself as competitive for college admission as possible, read this article on building the most versatile college application. Want to improve your SAT score by 160 points or your ACT score by 4 points?We've written a guide for each test about the top 5 strategies you must be using to have a shot at improving your score. Download it for free now: Have friends who also need help with test prep? Share this article! Tweet Justin Berkman About the Author Justin has extensive experience teaching SAT prep and guiding high school students through the college admissions and selection process. He is firmly committed to improving equity in education and helping students to reach their educational goals. Justin received an athletic scholarship for gymnastics at Stanford University and graduated with a BA in American Studies. Get Free Guides to Boost Your SAT/ACT Get FREE EXCLUSIVE insider tips on how to ACE THE SAT/ACT. 100% Privacy. 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Chemical Safety In Schools Environmental Sciences Essay

Chemical Safety In Schools Environmental Sciences Essay Chemistry plays an important role in human civilization. It enables us to formulate substances important for disease treatment, fertilize plants and provide fuel for transportation ( ). For many years, chemistry has been considered the central science due to its significant connections and overlap with other sciences. If a scientific discipline involves matter, chances are that chemistry plays an important role. Therefore, we will always need people who have a good knowledge of chemistry. As expressed by Beach and Stone (1988) â€Å"chemistry education without laboratory is like painting without colors and canvas or learning how to ride a bike by reading its operating manual† (Tezcan and Bilgin, 2004). The study of chemistry in schools equips students with knowledge in the classroom and skills of conducting experiments in laboratories during practical sessions that are scheduled once a week for a period of two to three hours (MOH, 2001). 2.1.2 Hazards Chemical in the School E xperiments The teaching of chemistry at secondary school includes the use of hazardous chemical, which is essential for the understanding of chemistry fundamentals. Example of hazardous chemicals that are available at school chemistry laboratory are hydrochloric acid, sulfuric acid, acetic acid, natrium hydroxide, hydrogen sulfate, ammonium sulfate, hydrogen peroxide, ethanol, propanol and acetone (MOH, 2000). These chemicals are classified as hazardous chemicals to health under the Malaysia Occupational Safety and Health (Use and Standards of Exposure of Chemical Hazardous to Health) Regulations 2000. In view of their hazardous characteristics, the government through the Department of Occupational Safety and Health regulates labelling and packaging of these chemicals. A specific law pertaining to these hazardous chemicals, the Occupational Safety and Health (Classification, Packaging John Kiesswetter et al., 1994; Medinsky et al., 1995). Malaysian Occupational Safety & Health (Ac t 514) and Occupational Safety & Health Regulation 2000 (Use and Standard of Exposure to Chemicals Hazardous to Health) specify the permissible exposure level (PEL). The PEL is the maximum time-weighted average concentration of hazardous chemicals in the air of working area that workers can be exposed without the need to wear personal protective equipment and the PEL for acetone, ethanol and formaldehyde are 1187.0, 1880.0 and 0.4 mg/m3, respectively (MDC, 2005). 2.1.3 Safety Precautions In view of the physical and health hazards of the chemicals, there is requires the implementation of safety precaution and hazard control to reduce the risk of exposure to the chemical hazards. Safety precaution differs based on the type of the chemical hazards. Safety precautions differ based on the type chemical hazards. General safety precaution is personal hygiene whereby the user as advice:

Methodological Issues in Interviewing Dissertation

Methodological Issues in Interviewing - Dissertation Example The type of methodology adopted in a study is influenced by the nature of the reaches and the topic that is being studied. When a researcher is deicing on the methodology to adopt for a particular study, he/she must think of how the research questions and the hypotheses are going to be addressed. The methodology should clearly describe how the study can be replicated in another situation. Every stage of the process must be explained and justified. Â  Krueger (2008) describes secondary research is an approach to research in which existing information is summarized, collated, and synthesized. In secondary research, the researcher uses information and data that had been collected by other researchers. A variety of sources are used in secondary research. They include letters, documents, previous primary studies, books, journals, diaries, autobiographies, and archival records (Saunders et al., 2009). Magazines articles, marketing reports, and data from company websites can also be used in secondary studies. There are several advantages of using secondary research. First, it saves the researcher a lot of times. In this approach, the researcher does not have to go to the field to collect primary data. On the contrary, he uses information that is already documented. This allows him to spend more time in analyzing the data (Saunders et al., 2009). Secondly, secondary research allows the researcher to approach a subject or topic of stu dy from different perspectives. The use of a variety of sources to collect data allows the researcher to understand and evaluate the perspectives of another researcher on the topic of study. Secondary research also gives the researcher general background information on the topic of study.