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2017

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Articles 2401 - 2430 of 12521

Full-Text Articles in Physical Sciences and Mathematics

Ground-Level Ozone Sep 2017

Ground-Level Ozone

Activities

In this exercise we will be examining ground-level ozone, commonly referred to as "smog" ("smoke" + "fog" = "smog"). Smog is formed by the combination of air pollutants and sunlight, and can have adverse effects on humans and other organisms. You have likely heard of ozone in a different capacity. Ozone also occurs high above the earth's surface in the stratosphere, where it serves a protective function by blocking harmful ultraviolet radiation from the sun. The ozone in each case is the same molecule (three bound oxygen atoms), but in one location (high in the atmosphere) it is beneficial to …


Calories And Land Sep 2017

Calories And Land

Activities

In this exercise, you will investigate how your own diet affects the agricultural demands of a country. You will do this by monitoring your food and drink intake for 3 days, and recording it on the attached activity sheet. At the end of this time, you will add up the number of calories consumed and find the average amount for each day. Most of your packaged food should come with some type of caloric guidelines. If it does not, a fairly complete listing of the calories of various foodstuffs can be found here. As best you can, you need to …


Soil Composition Sep 2017

Soil Composition

Activities

Soil, dirt, sediment, what’s the difference? Depending upon whom you ask, you might get a radically different answer. Some sources state that the only difference between them has to do with their location: soil is the unconsolidated material on the ground, dirt is that same matter on your hands or clothes, and sediment is the same material on the bottom of a river or lake. Others define the differences based upon the size and shape of the material grains. For the purposes of this activity, we are going to define things the following ways. Soil is a complex, unconsolidated mixture …


Rock Identification Sep 2017

Rock Identification

Activities

In our everyday lives, we often find confusion between the terms rock and mineral. People will sometimes use the terms interchangeably since they are both found in the ground. However, they are distinctly different things. Minerals are solids with a definite chemical composition and crystalline structure. While rocks can be made of minerals, and therefore have some of these same properties, they can also be made of materials such as volcanic glass that do not contain a single crystal. The problem is that we do not have a really clear definition of a rock. Different sources will define the term …


Carbon Cycle Capstone Sep 2017

Carbon Cycle Capstone

Activities

For this module's Capstone Activity, we will be examining the idea of Carbon Credits. In the first two weeks of this laboratory module you saw how vegetation can sequester carbon in its tissues, and how the processes of photosynthesis and respiration affect the cycling of carbon dioxide. By integrating these activities with the carbon dioxide calculator exercise, you will determine the number of trees that would be needed to offset your personal carbon dioxide emissions. Complete the activities and questions on the Capstone Activity sheet.


Personal Carbon Impacts Sep 2017

Personal Carbon Impacts

Activities

We have seen that plants sequester large sums of carbon in themselves. They are able to do this since, on average, photosynthesis produces more sugar than what is need by the plant during its respiration phase. As long as the plant is alive, it will continue to take carbon dioxide out of the air. However, we also found that a plant will return all of that carbon dioxide back into the atmosphere after it dies if the wood is burned or allowed to decay. In this week's lab, we are going to investigate what effect mankind has on the carbon …


Carbon Cycling Sep 2017

Carbon Cycling

Activities

So let's take a minute and recap. You know that plants carry out photosynthesis to create sugar, and that all organisms use sugar to fuel cellular biochemical reactions through the process of cellular respiration. Not all of the sugar created by the plant is used up in respiration though, as some is used to create new plant biomass like roots, leaves, stems, wood, and bark. The carbon in plant biomass is only stored temporarily, as it will return to the atmosphere when the biomass decomposes, burns, or is eaten and metabolized. Up to now you have read about the abstract …


Trees And Carbon Sep 2017

Trees And Carbon

Activities

To understand the environment, it is important to understand how organisms and their surroundings interact. Since all organisms use energy, we need to understand how energy can be used and transferred. Because all organisms are made of substances, it is equally important that we understand how chemicals are used and transported through an ecosystem. This exercise will help contribute to our understanding of the movements of compounds in ecosystems. The transport and transformation of substances in the environment are known collectively as biogeochemical cycles. These global cycles involve the circulation of elements and nutrients that sustain both the biological and …


Ecological Footprint Sep 2017

Ecological Footprint

Activities

Estimating your overall impact on the environment is a daunting task when you consider all the variables involved. Environmental scientists have developed a tool that does just this however, and presents the information in a manner that is easily visualized despite the underlying complexities. It is known as an “ecological footprint”, and it describes the area of land needed to supply the resources used and wastes produced by each individual. Nature’s ability to provide resources and process wastes is known as “natural capital”, and the goal of sustainable living is to use resources wisely so as to avoid depleting natural …


Fossil Fuel Capstone Sep 2017

Fossil Fuel Capstone

Activities

In this capstone activity, we are going to try to look at our individual fossil fuel usage. It would be nice if we could actually calculate how much each on of us is responsible for using. However, a great deal of our personal fossil fuel usage is hidden from us and almost impossible to calculate. For instance, the food that we eat was produced using oil in the fertilizer spread on the crops, fuel in the tractors that plowed the field, and diesel in the trucks that brought the food to market, amongst other things. The newspaper you read in …


Natural Gas Sep 2017

Natural Gas

Activities

In the world of fossil fuels, natural gas is often the overlooked ugly duckling. It gets lumped in with oil, as in “oil and gas industry”, even though the discussion usually centers upon oil. It does not help that gasoline, which is derived from oil, is shortened to “gas”. In many people’s mind, the “gas” in “oil and gas” refers to gasoline, and not natural gas. However, natural gas has much to offer as an energy source that makes it preferable to other forms of fossil fuels. It burns much cleaner than coal or oil, and it produces far less …


Coal Sep 2017

Coal

Activities

Coal has been a source of energy for almost as long as Homo sapiens have inhabited the planet. The earliest record for its use dates back more than 3000 years to China where it may have been used to smelt copper. In areas where coal seams intersected the surface, coal was a ready supply of energy just waiting to be exploited. It did have some drawbacks, though. Most of the coal near the surface burns dirty, requiring some form of chimney if it is to be used indoors. It is also heavy to transport, limiting its use to regions near …


Oil Sep 2017

Oil

Activities

We are a country that runs on oil. From the gasoline in our cars to the plastic in our computers to the detergents that we put in our dishwashers, we rely on oil for our modern way of life. It cannot be understated just how strong of a role it plays in our economy and politics. It is used in tractors that plow and harvest food. It is used to power manufacturing plants and as feedstock in commercial goods. It powers all the trains and trucks that bring goods to market. It runs our cars, heats and cools our homes, …


Nuclear Energy Capstone Sep 2017

Nuclear Energy Capstone

Activities

The United States has a problem with energy independence. The problem has nothing to do with a lack of energy production or availability. We are the largest producer of energy in the world, and have centuries’ worth of fossil fuels, as well as an enormous supply of nuclear and alternative energies, at our disposal. Our energy dependence on other countries is a result of the fact that we are also the leading consumers of energy in the world, being second only to Canada (population 32 million, compared to the 283 million in the U.S.) in per capita consumption of energy. …


Radiation Exposure Sep 2017

Radiation Exposure

Activities

Nuclear energy was going to make the world a much better place during the 1950’s. The promise of an almost limitless supply of cheap energy that did not produce any soot or atmospheric pollutants almost seemed to good to be true. During the 1960's and 1970's, the United States nuclear industry expanded, as fears of a looming end to oil and gas reserves fueled construction. But by the late 1970’s, though, the wheels had come off of the nuclear wagon. The cheapness of the energy never did pan out, as prices of electricity from nuclear energy rivaled those of fossil …


Nuclear Power Plants Sep 2017

Nuclear Power Plants

Activities

As we discussed in the last activity, energy is released when isotopes decay. This energy can either be in the form of electromagnetic radiation or the kinetic energy of the nuclear fragments. The important question for us is, “How can this energy be converted into a useful form like electricity?” The most obvious thing to do is to allow either of these forms of energy to be absorbed by a substance in order to increase its internal energy and thus, increase its temperature. As the substance warms up above its surroundings, a temperature difference is created, and allows for any …


Nuclear Decay Sep 2017

Nuclear Decay

Activities

Almost any phrase that has the word “nuclear” in it has a bad reputation. The term conjures up images of mushroom clouds and radioactive mutants. It is interesting to note that in the 1940’s and 50’s, the term that applied to energy derived from the decay radioactive material was atomic energy. This term was somewhat correct, since the energy was coming from the breakdown of the atom. It was not until later that the more appropriate term nuclear energy was used as more people began to understand that the energy was coming from the breakdown of the nucleus of the …


Home Energy Capstone Sep 2017

Home Energy Capstone

Activities

The other three weeks of the Home Energy Module study energy flow and usage in our homes. In the R-Factor activity, we observed that the material used in the construction of our homes has a tremendous impact on the rate at which heat flows through its exterior surfaces. In Home Audit and Home Analysis activities, we performed an energy audit of our homes to estimate the amount of money that it costs to power it. As you have seen during our studies, there are many factors that affect the cost of energy in our homes. The right choices of materials, …


Home Analysis Sep 2017

Home Analysis

Activities

The average household spends over $1,300 a year for energy to run the many devices found in the home. In this week's lab, we are going to investigate ways to save both energy and money that will not seriously impact your current lifestyle, i.e. you can keep watching as much television as you like, but you might want to put on a sweater to do it. In order to do this, we are going to have to use the measurements of our homes that we made two weeks ago. Last week, we studied how different materials affect the amount of …


R-Factor Of Various Materials Sep 2017

R-Factor Of Various Materials

Activities

Even though it has been over 150 years since the First Law of Thermodynamics was discovered, we still find that heat is misunderstood. For example, the many environmental science textbooks define heat as "the total kinetic energy of atoms or molecules in a substance not associated with bulk motion of the substance." THIS IS WRONG! What these books are describing is the thermal energy of a system. This is a common misconception. While heat is energy, it is not a containable form of energy since, by its very definition, heat is energy that is transferred. In particular, heat is the …


Home Energy Audit Sep 2017

Home Energy Audit

Activities

In the 1800's, scientists found, empirically, that rules exist that determine how energy can be transferred. The first of these rules is called the First Law of Thermodynamics. This law is usually stated as, "Energy can neither be created nor destroyed; it can only be transferred from one form to another." This often leads to the re-titling of this law as the Conservation of Energy Principle since it says that energy must be conserved. This statement of the First Law does not say anything about how energy can be transferred, though. It turns out that there are only two ways. …


Basic Skills Capstone B Sep 2017

Basic Skills Capstone B

Activities

If you look at the leaves that fall off of the trees in autumn, you will notice that not all leaves of the same kind are alike. Some are larger than others, some are longer or wider, some have different stem lengths, and some may have slightly different shapes. This is not surprising if you consider that they may be from different trees. Just as two people have hands or feet of different sizes, so different trees may have leaves of different sizes. If you do further observations, however, separating out leaves found under one tree from leaves found under …


Basic Skills Capstone A Sep 2017

Basic Skills Capstone A

Activities

In the late spring and summer, many parts of the United States experience smog alert days - days when the concentration of pollutants in the air has been considered unhealthy. Many of these pollutants are produced by automobiles - particularly hydrocarbons, carbon monoxide, nitrogen oxides and, indirectly, ozone. Most discussion of the adverse effects of smog center on humans, and the effects on other forms of life, such as plants, are scarcely mentioned. So how does air pollution from automobiles affect plant growth? Let's think about how this hypothesis might be tested. Two problems must be addressed. The first is …


Measurement Sep 2017

Measurement

Activities

In general, you are quite familiar with measurements, as almost any occupation requires measurements of some kind. Carpenters measure boards for cutting, nurses measure blood pressure in patients, tailors measure fabric for garments, and advertising executives measure the public's acceptance of their sales pitches. You will therefore undoubtedly be utilizing measurement in your chosen career, regardless of the field you enter. Measurement plays a particularly large role in science. In their studies, scientists gather data, and to do this they use measurements. Scientists measure the concentration of gases in the atmosphere, the growth of organisms under varying conditions, the rate …


Statistics And Graphing Sep 2017

Statistics And Graphing

Activities

Statistics - they're all around us, and we're exposed to them every day. They allow us to summarize large volumes of mathematical information, and so are found wherever there's data to be presented. Let's say you're watching your favorite college football team, and the game has come down to a last second thirty-five yard field goal attempt for the win. When describing the kicker's past performance in this range, the play-by-play announcer doesn't list all of the kicker's attempts one by one and their outcome, he simply states the percentage of kicks made in this yard range. If the kicker's …


Experimental Analysis Sep 2017

Experimental Analysis

Activities

Central to good science are accurate observations, testable hypotheses, well-designed experiments or other tests, and reasonable data analyses. The purpose of Laboratory 1 is to introduce you to the basics of designing and analyzing experiments. The following two laboratory exercises will provide you with further steps in organizing and analyzing data. Many interesting experiments are impossible to do in a normal undergraduate science laboratory setting. For this reason, your introduction to designing an experiment that has relevance in “the real world” involves a computer simulation. The program involves a growing industry, that of farming fish. What is your favorite kind …


Lcs-1: A High-Resolution Global Model Of The Lithospheric Magnetic Field Derived From Champ And Swarm Satellite Observations, Nils Olsen, Dhananjay Ravat, Christopher C. Finlay, Livia K. Kother Sep 2017

Lcs-1: A High-Resolution Global Model Of The Lithospheric Magnetic Field Derived From Champ And Swarm Satellite Observations, Nils Olsen, Dhananjay Ravat, Christopher C. Finlay, Livia K. Kother

Earth and Environmental Sciences Faculty Publications

We derive a new model, named LCS-1, of Earth’s lithospheric field based on four years (2006 September–2010 September) of magnetic observations taken by the CHAMP satellite at altitudes lower than 350 km, as well as almost three years (2014 April–2016 December) of measurements taken by the two lower Swarm satellites Alpha and Charlie. The model is determined entirely from magnetic ‘gradient’ data (approximated by finite differences): the north–south gradient is approximated by first differences of 15 s along-track data (for CHAMP and each of the two Swarm satellites), while the east–west gradient is approximated by the difference between observations taken …


Ar(1) Sequence With Random Coefficients:Regenerative Properties And Its Application, Krishna B. Athreya, Koushik Saha, Radhendushka Srivastava Sep 2017

Ar(1) Sequence With Random Coefficients:Regenerative Properties And Its Application, Krishna B. Athreya, Koushik Saha, Radhendushka Srivastava

Communications on Stochastic Analysis

No abstract provided.


Randomized Trial Of Interventions To Improve Childhood Asthma In Homes With Wood-Burning Stoves, Curtis W. Noonan, Erin O. Semmens, Paul Smith, Solomon W. Harrar, Luke Montrose, Emily Weiler, Marcy Mcnamara, Tony J. Ward Sep 2017

Randomized Trial Of Interventions To Improve Childhood Asthma In Homes With Wood-Burning Stoves, Curtis W. Noonan, Erin O. Semmens, Paul Smith, Solomon W. Harrar, Luke Montrose, Emily Weiler, Marcy Mcnamara, Tony J. Ward

Statistics Faculty Publications

BACKGROUND: Household air pollution due to biomass combustion for residential heating adversely affects vulnerable populations. Randomized controlled trials to improve indoor air quality in homes of children with asthma are limited, and no such studies have been conducted in homes using wood for heating.

OBJECTIVES: Our aims were to test the hypothesis that household-level interventions, specifically improved-technology wood-burning appliances or air-filtration devices, would improve health measures, in particular Pediatric Asthma Quality of Life Questionnaire (PAQLQ) scores, relative to placebo, among children living with asthma in homes with wood-burning stoves.

METHODS: A three-arm placebo-controlled randomized trial was conducted in homes with …


Taming Charge Transport In Semiconducting Polymers With Branched Alkyl Side Chains, Bob C. Schroeder, Tadanori Kurosawa, Tianren Fu, Yu-Cheng Chiu, Jaewan Mun, Ging-Ji Nathan Wang, Xiaodan Gu, Leo Shaw, James Kneller, Theo Kreouzis, Michael F. Toney, Zhenan Bao Sep 2017

Taming Charge Transport In Semiconducting Polymers With Branched Alkyl Side Chains, Bob C. Schroeder, Tadanori Kurosawa, Tianren Fu, Yu-Cheng Chiu, Jaewan Mun, Ging-Ji Nathan Wang, Xiaodan Gu, Leo Shaw, James Kneller, Theo Kreouzis, Michael F. Toney, Zhenan Bao

Faculty Publications

The solid-state packing and polymer orientation relative to the substrate are key properties to control in order to achieve high charge carrier mobilities in organic field effect transistors (OFET). Intuitively, shorter side chains are expected to yield higher charge carrier mobilities because of a denser solid state packing motif and a higher ratio of charge transport moieties. However our findings suggest that the polymer chain orientation plays a crucial role in high-performing diketopyrrolopyrrole-based polymers. By synthesizing a series of DPP-based polymers with different branched alkyl side chain lengths, it is shown that the polymer orientation depends on the branched alkyl …