Importance of Accelerometer Selection

Importance of Accelerometer Selection Accelerometer: Vibrations are everywhere in our lives. They may be generated and transmitted by different things, such as motors, turbines, machines and plants, structures and buildings, or even by human body. Some vibrations are desirable, and some of them can be disturbing or destructive. So understanding the causes of vibrations, measuring and reducing them is important. Accelerometer is a device, designed to measure vibrations in different situations and environments. Function: The heart of an accelerometer is a piezoelectric material (like quartz or ceramic crystal). Figure shows this material as a disc for piezoelectric effect explanation. Imagine that piezoelectric material (the disk) is located between two electrodes, like a capacitor. When a force is applied perpendicular to the disk, a voltage is produced at the electrodes. This phenomenon is called piezoelectric effect. Main elements of an accelerometer are piezoelectric material and seismic mass (Figure ). A seismic mass is attached to one side of the disk, and another side is attached to a sensor. When the accelerometer is subjected to vibration, a generated force acts on the piezoelectric element. According to Newtons Law, this force is equal to the product of the seismic mass and the acceleration (m.a). Based on the piezoelectric effect, an output charge is generated, proportional to the applied force. Since the seismic mass is constant, the output charge signal is proportional to the acceleration of the mass. In wide frequency ranges, sensor and seismic mass have the same acceleration amount, as a result, the sensor measures the acceleration of the test sample (Ref). Different types: In sum, four main types of accelerometers are available; Premium grade accelerometers are made from premium crystals and use low noise circuitry to produce a premium. They have steel cover and this cover can protect them in harsh industrial environments. Industrial grade accelerometers are prevalent in different industries and used on different machines, equipment and plants. High vibration accelerometers are used to monitor high vibration levels, and have a lower output (10 mV/g) and lower mass, in compared with industrial accelerometers. Triaxial accelerometers measure vibration in the X, Y, and Z axes. They have three crystals and they react to vibration in different axis. As a result, the output has three signals, for X, Y, and Z axes (Ref) Accelerometer selection: For getting the best result of using accelerometer in a test, sort of issues must be considered. Based on these issues we can determined the most suitable accelerometer, based on its features, for our test. The first and foremost issue that we must consider is the amplitude of the vibration that we are going to monitor. Frequency range that we are going to study is important to choose an appropriate accelerometer (Ref). Another issues are effective in accelerometer selection, such as the temperature range of the installation area, size of the sample in the test, existence of magnetic field in the test environment, and existence of electrical noise in the test area. Other environmental issues are considerable, for example amount of humidity of test environment, or if accelerometer installation can alert the vibration characteristics in the test or not (Ref). Accelerometer installation: As it was discussed before, accelerometer selection has an important role to get more accurate results. But to achieve this goal, installation of accelerometer is important too. Some points and issues that must be considered during the installation of accelerometer: the surface of installation must be clean and grounded (Ref). The selected location for installation must provide a short and rigid path to the vibration source (Ref). For example, for getting better result in a vibration transmission from road surface test,the closest point to the wheels on the unsprung mass and the chassis near the suspension are recommended. Selected Accelerometer: Selected accelerometer for this test, based on needs and test conditions, is PBC model: 356A32. This model is a Triaxial type, with high sensitivity ( ±10%) 100 mV/g (10.2 mV/(m/s ²)), measurement range of  ±50 g pk ( ±491 m/s ² pk), broadband resolution: 0.0003 g rms (0.003 m/s ² rms), and frequency range of ( ±5%) 1.0 to 4000 Hz (Ref). Figure shows this accelerometer. Selected accelerometer for this test, based on needs and test conditions, is PBC model: 356A24. This model is a Triaxial type, with low sensitivity ( ±10%) 10 mV/g (1.02 mV/(m/s ²)), measurement range of  ±500 g pk ( ±4905 m/s ² pk), broadband resolution: 0.004 g rms (0.04 m/s ² rms), and frequency range of ( ±5%) 1.0 to 9000 Hz (Ref). Figure shows this accelerometer.

Essay --

Skin Cancer My topic has to do with the skin because it is about skin cancer which, obviously, occurs on the skin .Skin cancer is an abnormal and somewhat rapid growth of skin cells. Often occurs in areas of the skin that is exposed to the sun. UV rays from the sun can cause mutations to the cells we learned about such as the basal cell, squamous cell, and melanoma. In the United States the most common form of cancer is probably skin cancer. About 3.5 million cases of basal and squamous cell skin cancer are recorded each year in the United States alone. There are three major types of skin cancer. Those would be basal cell carcinoma, squamous cell carcinoma, and melanoma. Basal and squamous cell cancers are set apart from the more dangerous and serious type of cancer which would be melanoma. The two got their names because they usually start in the basal cells or squamous cells. â€Å"Most basal and squamous cell cancers develop on sun-exposed areas of the skin, like the face, ear, neck, lips, and the backs of the hands. Depending on the type, they can be fast or slow growing, but they rarely spread to other parts of the body.† (ACS) Because they don’t usually spread to other parts of the body, basal and squamous cell cancers are considered less dangerous compared to the melanoma. As of 2013 there have been 76,600 cases of melanoma and causes more than 9,000 of the 12,000 skin cancer deaths each year. Like most or all skin cancer melanoma is almost always curable in its early stages. Basal cell cancers are strange, uncontrolled growths that occur on the outermost layer of the epidermis. This type of cancer often looks like red patches, open sores, shiny bumps, or scars. They can become highly disfigured if they are all... ...y, and biological therapy. Freezing is when the doctor freezes the cancer cells using liquid nitrogen; the dead tissue will come off when it thaws. Excisional is when the doctor cuts off the cancerous tissue. Laser therapy uses an intense beam of light to break down and destroy growths without heavily damaging the surrounding tissues. Mohs surgery is for larger, more difficult cancers. The doctor removes the skin growth layer by layer and examines each one until none of the growth remains. Radiation therapy is used when doctors are unable to perform surgeries. Chemotherapy uses drugs to kill the cancer cells. If the cancer is at the top layer then creams would be used but if it is deeper down then drugs could be injected into the blood stream through veins. Biological therapy uses biological treatments to stimulate the immune system to kill the cancer cells.

Apes Chapter 3 Questions

Chapter 3 Reading Questions: 1. Core Case Study: â€Å"Have you thanked your insects today? †- Explain why insects are significant. Many of the earth’s plant species depend upon insects to pollinate them. Carnivorous insects, such as the praying mantis, control the ‘pest’ insect population. 2. What percentage of the species on this planet consists of insects? Animals? Plants? 53% are insects; 20% are other animals; 18% are plants. 3. Give three examples of how we benefit from microbes.Soil bacteria convert nitrogen gas into usable forms for plants; they decompose wastes into nutrients we use; they help produce various foods such as bread, cheese, wine, beer, and tofu. 4. What percentage of the biomass on this planet accounts for microbes? 90% of earth’s living mass. 5. Define the four spheres of the earth. The atmosphere is the thin membrane of air around the planet. The troposphere is the air layer about 11 miles above sea level. The stratosphere li es above the troposphere between 11-30 miles; it filters out the sun’s harmful radiation.The hydrosphere consists of earth’s water, found in liquid water, ice, and water vapor. The lithosphere is the crust and upper mantle of the earth’s soil. It contains nonrenewable fossil fuels, minerals, and soil, and renewable soil chemicals needed for plant life. The biosphere includes most of the hydrosphere, parts of the lower atmosphere and upper lithosphere. All parts of the biosphere are interconnected. 6. Describe the three interconnected factors that life depends on. The flow of high-quality energy; the cycling of matter or nutrients; gravity. 7.Describe what happens to all of the solar radiation that reaches the earth. Solar energy flowing through the biosphere warms the atmosphere, evaporates and recycles water, generates winds, and supports photosynthetic life. 8. Is the greenhouse effect a positive or negative issue for life on earth? Explain why. It is a positi ve effect because without it, the earth would be too cold to support most forms of life. 9. Explain the following terms: abiotic, biotic, range of tolerance. Abiotic consists of non-living components such as water, air, nutrients, and solar energy.Biotic consists of biological components such as producers, consumers, and decomposers. Each population in an ecosystem has a range of tolerance to variations in its physical and chemical environment. 10. Explain how limiting factors can control population size. Too much or too little of any abiotic factor can limit or prevent growth of a population, even if all other factors are at or near the optimum range of tolerance. 11. What factors usually limit terrestrial populations? On land, precipitation and soil nutrients are often limiting factors. 2. What factors usually limit aquatic populations? In water, temperature, sunlight, nutrient availability, dissolved oxygen content, and salinity are limiting factors. 13. What is the overall chemi cal reaction for photosynthesis? 6CO2 + 6H2O (+ light energy) C6H12O6 + 6O2. 14. What is the overall chemical reaction for respiration? C6H12O6 + 6O2 —> 6CO2 + 6H2O + 36 ATP 15. Why are decomposers so significant to an ecosystem? They recycle the nutrients that make life possible throughout the ecosystem. 16.Why is biodiversity one of our most important renewable resources? Biodiversity provides us with natural resources, natural services, pleasure, and keeps the balance of the food web. 17. Describe 4 key components of biodiversity. Functional diversity includes the biological and chemical processes such as energy flow and matter recycling needed for the survival of species, communities, and ecosystems. Ecological diversity includes the variety of terrestrial and aquatic ecosystems found in an area or on the earth.Species diversity includes the number of species present in different habitats. Genetic diversity includes the variety of genetic material within a species or popu lation. 18. What are the five major causes of species decline? Habitat destruction and degradation, invasive species, pollution, and human population growth. 19. Summarize two approaches to sustaining biodiversity. The ecosystem approach protects populations of species in their natural habitat by preserving sufficient areas of habitats in different biomes and aquatic systems.The species approach protects species from premature extinction by indentifying endangered species and protecting their critical habitats. 20. What trophic level do decomposers consume from? Decomposers process detritus from all trophic levels. 21. What form of energy is transferred from one organism to another? Stored energy in the tissues of the organism. 22. Why would the earth be able to support more people if we ate at a lower trophic level? The energy intake would be higher because there is less loss of energy. 23.Why are there rarely more than 4 or 5 trophic levels within an ecosystem? Because the food we b would not be able to sustain that great of an energy loss in successively higher levels. 24. What is the significance of net primary productivity? NPP measures how fast producers can provide the food needed by other organisms in an ecosystem. 25. What might happen to us and to other consumer species as the human population grows over the next 40-50 years and per capita consumption of resources such as food, timber, and grassland rises sharply?What are the three ways to prevent this from happening? We will end up pushing other species to extinction and reduce the biodiversity in earth. To prevent this, we can prevent population growth, find renewable energy sources, and consume food locally and at a lower trophic level. 26. Consider the diagram on page 67 (figure 3-22). Explain why desertification is so significant of an issue and relate that to the significance of net primary productivity. Dry land ecosystems are already such fragile ecosystems, and many of these delicate ecosyste ms have the most net productivity. 7. Describe the four types of soil horizons. The surface litter layer (O horizon) is the top layer and consists of freshly fallen undecomposed or partially decomposed leaves, twigs, crop wastes, animals waste, fungi, and other organic material. It is normally brown or black. The topsoil layer (A horizon) is a porous mixture of the partially decomposed bodies of dead plants and animals, called the humus and inorganic materials such as clay, silt, and sand. The B and C horizons (subsoil and parent material) contain most of a soils inorganic material and lies on bedrock. 8. How does color relate to the quality of the topsoil? The color of the topsoil suggests how useful a soil is for growing crops. Dark brown or black soil is rich in organic matter and nitrogen. Gray, bright yellow or red topsoils are the opposite. 29. What are the significant properties of soil? Soil texture: particle size of components. 30. How do humans impact the hydrological cycl e? We alter the water cycle by withdrawing large amounts freshwater, clearing vegetation, and eroding soils, polluting surface and underground water, and contributing to climate change. 1. Be able to diagram the entire Carbon cycle. See below 32. What is the significance of burning fossil fuels on the C cycle? Adds more carbon to the air. 33. How are Carbon and Nitrogen used by living organisms? Carbon and nitrogen make up organisms and are used in respiration by them. 34. What two natural processes convert nitrogen gas in the air to a usable form? Nitrogen fixation, Nitrification. 35. How is the C & N Cycle affected by humans? We add large amounts of nitric oxide in the air and we add fertilizers to the water and soils.

The Future of Psychological Profiling - 1658 Words

The Future of Psychological Profiling CJ430-01: Psychological Profiling Professor William Formby Kaplan University May 18, 2012 The purpose of this paper is to provide an assessment of psychological profiling as an investigative tool for the future. The paper will try to focus on what happens if profiles are developed that have not accurately portrayed the apprehended. Additionally this paper will be reviewing the Baton Rouge Serial Killer and The Unabomer cases in order to answer additional questions such as; what were the main criticisms documented in these specific cases, how can a profiler achieve the desired end results using the resources available, and what future challenges do you see this approach facing as more†¦show more content†¦Why did she become a victim? Was he organized or disorganized? Using geography can we tell if he lived nearby or, was this act random and he lives far away? A profiler will have to use everything he or she knows about human behavior, and everything they learned in school and apply it to a real crime scene to be successful. What does the future really hold for profiling and what challenges does it face as an investigative tool? Well, profiling is not going anywhere if people think it is going to be a passing fad or fade away it is not. It is only going to get stronger. Evidence of that is the fact that the FBI regularly staffs the Behavioral Science Unit (BSU), with 12 profilers who handle over 1.000 cases a year. The BSU conducts training, research, and consultation in; â€Å"Applied Behavioral Science, Conflict and Crisis Management, Futuristic, Juvenile Crime and Behavior, Managing Death Investigations, Psychosocial Behavior of Violent Street and Prison Gangs, Spirituality, and Wellness, and Vitality; Stress Perception and Memory; and Psychopathology† (O Connor, 2012). (Holmes amp; Holmes, 2009), believes that with the right training especially with the ones closest to the crime such as police officers, profiling will be in a great position to advance remarkable. (Holmes amp; Holmes, 2009), also discuss the fascinating concept of computerized profiling. Computerized monitoring of offenders isShow MoreRelatedThe Killing Of Two Young Men905 Words   |  4 PagesOur young people are feeling and seeing the effects of all this racial profiling and this is going to cause them to have psychological problems in the future. 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