What teachers are saying about Study. Are you still watching? Your next lesson will play in 10 seconds. Add to Add to Add to. Want to watch this again later? Secondary Data in Marketing Research: Definition, Purpose and Role in Marketing Strategy. Legal Factors Affecting a Business.
Observational Research in Marketing: How to Establish a Marketing Research Project. What is Qualitative Research? What is Stakeholder Analysis? Research Methods in Psychology: Research Methods in Psychology for Teachers: Information Systems and Computer Applications. Devin Kowalczyk Devin has taught psychology and has a master's degree in clinical forensic psychology. Differentiating between different types of research articles is useful when looking at what has already been done.
Defining Primary and Secondary Research Let's say you are approached by an animal rights group, and they would like you to gather some information on the link between stress and pet ownership. Example Going back to our original example of the literature review on the effects of animals and stress, we need to determine what kind of research we will include in our write-up.
Differences If you haven't already suspected, the difference between primary and secondary research is primary is written by the researcher, while secondary is a reexamination. Try it risk-free No obligation, cancel anytime.
Want to learn more? Select a subject to preview related courses: Lesson Summary When examining past research, you are conducting a literature review , which is an examination of published material to understand what has already been said about the topic.
Learning Outcomes Once you've completed this lesson, you'll be able to: Define literature review Differentiate between primary and secondary research Explain when one would use primary research and when one would use secondary research. Unlock Your Education See for yourself why 30 million people use Study. Become a Member Already a member? Earning College Credit Did you know… We have over college courses that prepare you to earn credit by exam that is accepted by over 1, colleges and universities.
To learn more, visit our Earning Credit Page Transferring credit to the school of your choice Not sure what college you want to attend yet? Browse Articles By Category Browse an area of study or degree level. Job Options and Requirements Research Assistant: Career Profile Careers in Neuroscience Research: Job Options and Salary Info.
How to Become a Nurse Assistant. You are viewing lesson Lesson 8 in chapter 3 of the course:. Research Methods in Psychology 16 chapters lessons 12 flashcard sets.
Setting Up the Research Study. Data Collection Techniques in Qualitative Research Methods and Help and Review Educational Psychology: Tutoring Solution Introduction to Psychology: Certificate Program Research Methods in Psychology: Browse by Lessons Interpersonal Therapy: Tutoring Solution Clinical Assessment: Tutoring Solution Introduction to Anxiety Disorders: Tutoring Solution Stress Disorders: Latest Courses Computer Science Network Forensics Computer Science Latest Lessons Getting Started with Study.
Popular Courses Praxis Health Education Create an account to start this course today. Like this lesson Share. Browse Browse by subject. Upgrade to Premium to enroll in Psychology Research Methods in Psychology. Enrolling in a course lets you earn progress by passing quizzes and exams.
Take quizzes and exams. They collect data on customer service and the customer experience. Findings are reported back to the commissioning organization. There are many issues surrounding the ethics of such an approach to research. Focus groups are made up from a number of selected respondents based together in the same room.
Highly experienced researchers work with the focus group to gather in depth qualitative feedback. Groups tend to be made up from 10 to 18 participants. Discussion, opinion, and beliefs are encouraged, and the research will probe into specific areas that are of interest to the company commissioning the research.
Projective techniques are borrowed from the field of psychology. They will generate highly subjective qualitative data. There are many examples of such approaches including: Products are displayed in a mall of shopping center. Potential customers are asked to visit the store and their purchase behavior is observed. Observers will contemplate how the product is handled, how the packing is read, how much time the consumer spends with the product, and so on.
Diaries are used by a number of specially recruited consumers. They are asked to complete a diary that lists and records their purchasing behavior of a period of time weeks, months, or years. It demands a substantial commitment on the part of the respondent. However, by collecting a series of diaries with a number of entries, the researcher has a reasonable picture of purchasing behavior.
Both test reactors used liquid fluoride fuel salts. In a nuclear power reactor , there are two types of fuel. The first is fissile material, which splits when hit by neutrons , releasing a large amount of energy and also releasing two or three new neutrons.
These can split more fissile material, resulting in a continued chain reaction. Examples of fissile fuels are U, U and Pu The second type of fuel is called fertile. Examples of fertile fuel are Th mined thorium and U mined uranium.
Often the amount of fertile fuel in the reactor is far greater than the amount of fissile, but it cannot be fissioned directly. It must first absorb one of the 2 or 3 neutrons produced in the fission process, which is called neutron capture , then it becomes a fissile isotope by radioactive decay. This process is called breeding.
All reactors breed some fuel this way,  but today's solid fueled thermal reactors don't breed enough new fuel from the fertile to make up for the amount of fissile they consume.
This is because today's reactors use the mined uranium-plutonium cycle in a moderated neutron spectrum. Such a fuel cycle, using slowed down neutrons, gives back less than 2 new neutrons from fissioning the bred plutonium. Since 1 neutron is required to sustain the fission reaction, this leaves a budget of less than 1 neutron per fission to breed new fuel. In addition, the materials in the core such as metals, moderators and fission products absorb some neutrons, leaving too few neutrons to breed enough fuel to continue operating the reactor.
As a consequence they must add new fissile fuel periodically and swap out some of the old fuel to make room for the new fuel.
In a reactor that breeds at least as much new fuel as it consumes, it is not necessary to add new fissile fuel. Only new fertile fuel is added, which breeds to fissile inside the reactor. In addition the fission products need to be removed. This type of reactor is called a breeder reactor. If it breeds just as much new fissile from fertile to keep operating indefinitely, it is called a break-even breeder or isobreeder.
A LFTR is usually designed as a breeder reactor: Reactors that use the uranium-plutonium fuel cycle require fast reactors to sustain breeding, because only with fast moving neutrons does the fission process provide more than 2 neutrons per fission. With thorium, it is possible to breed using a thermal reactor. This was proven to work in the Shippingport Atomic Power Station , whose final fuel load bred slightly more fissile from thorium than it consumed, despite being a fairly standard light water reactor.
Thermal reactors require less of the expensive fissile fuel to start, but are more sensitive to fission products left in the core. There are two ways to configure a breeder reactor to do the required breeding. One can place the fertile and fissile fuel together, so breeding and splitting occurs in the same place.
Alternatively, fissile and fertile can be separated. The latter is known as core-and-blanket, because a fissile core produces the heat and neutrons while a separate blanket does all the breeding. Oak Ridge investigated both ways to make a breeder for their molten salt breeder reactor.
Because the fuel is liquid, they are called the "single fluid" and "two fluid" thorium thermal breeder molten salt reactors. The one-fluid design includes a large reactor vessel filled with fluoride salt containing thorium and uranium. Graphite rods immersed in the salt function as a moderator and to guide the flow of salt. In the ORNL MSBR design  a reduced amount of graphite near the edge of the reactor core would make the outer region under-moderated, and increased the capture of neutrons there by the thorium.
With this arrangement, most of the neutrons were generated at some distance from the reactor boundary, and reduced the neutron leakage to an acceptable level. In a breeder configuration, extensive fuel processing was specified to remove fission products from the fuel salt. The MSRE was a core region only prototype reactor. According to estimates of Japanese scientists, a single fluid LFTR program could be achieved through a relatively modest investment of roughly million dollars over 5—10 years to fund research to fill minor technical gaps and build a small reactor prototype comparable to the MSRE.
The two-fluid design is mechanically more complicated compared to the "single fluid" reactor design. The "two fluid" reactor has a high-neutron-density core that burns uranium from the thorium fuel cycle. A separate blanket of thorium salt absorbs the neutrons and its thorium is converted to protactinium Protactinium can be left in the blanket region where neutron flux is lower, so that it slowly decays to U fissile fuel,  rather than capture neutrons. This bred fissile U can be recovered by simple fluorination, and placed in the core to fission.
The core's salt is also purified, first by fluorination to remove uranium, then vacuum distillation to remove and reuse the carrier salts. The still bottoms left after the distillation are the fission products waste of a LFTR. One design weakness of the two-fluid design is the necessity for a barrier wall between the core and the blanket region, a wall that would have to be replaced periodically because of fast neutron damage.
The effect of neutron radiation on graphite is to slowly shrink and then swell the graphite to cause an increase in porosity and a deterioration in physical properties. ORNL chose not to pursue the two-fluid design, and no examples of the two-fluid reactor were ever constructed. One additional design weakness of the two-fluid design was its complex plumbing.
ORNL thought it necessary to use complex interleaving of the core and blanket piping in order to get a high reactor power level with acceptably low power density.
A two fluid reactor that has thorium in the fuel salt is sometimes called a "one and a half fluid" reactor, or 1. Like the 1 fluid reactor, it has thorium in the fuel salt, which complicates the fuel processing. And yet, like the 2 fluid reactor, it can use a highly effective separate blanket to absorb neutrons that leak from the core.
The added disadvantage of keeping the fluids separate using a barrier remains, but with thorium present in the fuel salt there are fewer neutrons that must pass through this barrier into the blanket fluid. This results in less damage to the barrier. Any leak in the barrier would also be of lower consequence, as the processing system must already deal with thorium in the core.
The main design question when deciding between a one and a half or two fluid LFTR is whether a more complicated reprocessing or a more demanding structural barrier will be easier to solve.
In addition to electricity generation , concentrated thermal energy from LFTR can enable application as Industrial process heat for many uses, such as ammonia production with the Haber process or thermal Hydrogen production by water splitting.
The Rankine cycle is the most basic thermodynamic power cycle. The simplest cycle consists of a steam generator , a turbine, a condenser, and a pump. The working fluid is usually water. A Rankine power conversion system coupled to a LFTR could take advantage of increased steam temperature to improve its thermal efficiency.
The working gas of a Brayton cycle can be helium, nitrogen, or carbon dioxide. The high-pressure working gas is expanded in a turbine to produce power. The low-pressure warm gas is cooled in an ambient cooler. The low-pressure cold gas is compressed to the high-pressure of the system. Often the turbine and the compressor are mechanically connected through a single shaft. A Brayton cycle heat engine can operate at lower pressure with wider diameter piping. The LFTR needs a mechanism to remove the fission products from the fuel.
Fission products left in the reactor absorb neutrons and thus reduce neutron economy. This is especially important in the thorium fuel cycle with few spare neutrons and a thermal neutron spectrum, where absorption is strong. The minimum requirement is to recover the valuable fissile material from used fuel. Removal of fission products is similar to reprocessing of solid fuel elements; by chemical or physical means, the valuable fissile fuel is separated from the waste fission products.
Ideally the fertile fuel thorium or U and other fuel components e. However, for economic reasons they may also end up in the waste. On site processing is planned to work continuously, cleaning a small fraction of the salt every day and sending it back to the reactor.
There is no need to make the fuel salt very clean; the purpose is to keep the concentration of fission products and other impurities e. The concentrations of some of the rare earth elements must be especially kept low, as they have a large absoprtion cross section.
Advantages and Disadvantages of Forecasting Methods of Production and Operations Management by Brian Bass; Updated July 27,
ABSTRACT This is a Health Evidence Network (HEN) synthesis report on the advantages and disadvantages of restructuring a health care system to be more focused on primary care services.
Learn about the advantages and disadvantages of quantitative research and how and when to use it versus qualitative methods in market research. Encyclopedia of Business, 2nd ed. Research Methods and Processes: Pr-Sa.
Research and Research Methods Survey Research Survey Advantages Survey Disadvantages Telephone Survey Mail Survey Online/Email Survey 2. See what's good and bad about latex beds and how a natural latex mattress compares to a synthetically created bed.