545 research outputs found
Gitelman's syndrome - incidentally detected in an elderly female
Potassium is critical for many important cell functions. Hereditary tubulopathies can also present in adults with symptoms of recurrent hypokalemia. A 60 year female who was worked up for persistent hypokalemia during repeated admission with different etiology and presenting complaints. Bartter’s syndrome and Gitelman’s syndrome represent distinct variants of primary renal tubular hypokalemic metabolic alkalosis and are easily distinguished on the basis of urinary calcium levels. Therapeutic options in gitelmans syndrome include supplementation of potassium and magnesium along with avoiding sodium depletion.
Role of Simulations in Student Learning: A Case Study Using Marketing Simulation
Simulations, like other pedagogical tools, should be evaluated for their effectiveness in achieving course objectives and student learning. This research examines the efficiency of using a particular simulation in achieving course objectives and student learning compared with a general textbook and other learning pedagogical tools from the students’ perspective
Monte Carlo Simulations of Nuclear Fuel Burnup
In the operation of a nuclear power plant, it is very important to determine the time evolution of material composition and radionuclide inventory during the entire operation of the plant. In the experiments, the Monte Carlo N-Particle eXtended (MCNPX) code was found to be accurate in predicting the uranium fuel depletion, the plutonium production and the buildup of most of the fission products in a nuclear reactor. The goal in this chapter is to analyze the effect of different nuclear fuel grades on the total radioactivity of the reactor core by employing nuclear burnup calculations for the three different fuels: mixed oxide fuel (MOX), uranium oxide fuel (UOX) and commercially enriched uranium (CEU), utilizing simulations with MCNPX code. The calculated results indicate that there is a buildup of plutonium isotopes for UOX and CEU, whereas there is a decline in the plutonium radioisotopes for MOX fuel with burnup time. The study of reactor neutronic parameters showed UOX fuel performs better relative to MOX and CEU. Zircaloy, with low thermal neutron absorption cross-section and high thermal conductivity, produced better results for the effective multiplication factor Keff and hence proved to be a much more effective clad material
Life Cycle Environmental Impact of Houston METRO System – Evaluation of Electric Alternatives
In the Greater Houston Area, mobile sources (on-and off-road vehicles) contribute the largest share of nitrogen oxide (NOx) emissions and second-highest share of volatile organic (VOC) emissions. The Houston METRO system is a key element in Houston\u27s infrastructure that can be expanded to lower emissions of criteria air pollutants (CAPs) and greenhouse gases (GHGs) and improve regional air quality. Currently, there is no comparative study for relative emissions and environmental impacts between passenger automobiles and METRO routes in Houston. Our research addressed this critical gap and developed environmental life cycle assessment for conventional diesel buses, diesel hybrid buses, and alternative electric buses in Houston using the GREET model. The life cycle GHG emissions of electric buses are slightly lower than the other two types of buses. However, all the other major emissions such as CO, NOx, PM10, PM2.5, VOCs, SOx, N2O, CH4, black carbon and primary organic carbon associated with electric buses are higher than diesel buses, thus causing higher environmental cost of electric buses than diesel buses. The life cycle costs of buses are very sensitive to future diesel and electricity prices. The results from this project would serve as a guiding framework to evaluate the effects of the decision to expand the METRO system and estimate the contribution of the METRO system in realizing the Greater Houston Area\u27s environmental objectives
Association of Polyethylene Glycol Solubility with Emerging Membrane Technologies, Wastewater Treatment, and Desalination
Forward osmosis (FO) and membrane distillation (MD) are two emerging membrane technologies, and both have advantages of low membrane fouling, ability to use for highly saline desalination, and feasibility to integrate with a low-grade heat source like solar collector. Because polyethylene glycol (PEG) is a flexible, water-soluble polymer, it is an essential material used for membrane fabrication and enhancement of membrane properties. Low-molecular-weight PEG sometimes is used as pore constrictor and pore former for developing MD membranes and support layer of FO membranes. Due to the affinity of PEG chains to water molecules, PEG, its derivatives, and copolymers have been widely used in the fabrication/modification of FO and MD membranes, which are currently applied to bioseparation, wastewater treatment, and desalination in academia and industry at the pilot scale. This chapter covers direct PEG and its membrane separation applications in wastewater treatment and desalination. The advancement of PEG in membrane science and engineering is reviewed and discussed comprehensively. We focus on the effectiveness of PEG on membrane antifouling and the stability of PEG-modified membranes when applied to wastewater treatment and desalination
Yield behavior of unoriented and oriented polycarbonate and polypropylene as influenced by temperature
The yield behaviors of an amorphous polymer (polycarbonate) and a crystalline polymer (polypropylene) were investigated over certain ranges of temperature. Both polymers were used in an unoriented (isotropic) and an oriented (anisotropic) condition. By using proposed yield criteria for the two structural conditions various theoretical yield loci are predicted; these are then compared with experimental findings based on a number of uniaxial and biaxial stress states. With a few exceptions that seem amenable to rational explanation the comparison between theory and experiment is most promising. The onset of yielding is defined by two methods: using a 0.3% offset and using the concept of plastic work. Similar findings result. Finally, for the range of parameters used in this study it is possible to compare individual results for a given material condition with a single yield locus, regardless of the temperature at which the tests were conducted.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23251/1/0000184.pd
Observations on Stratospheric-Mesospheric-Thermospheric temperatures using Indian MST radar and co-located LIDAR during Leonid Meteor Shower (LMS)
International audienceThe temporal and height statistics of the occurrence of meteor trails during the Leonid meteor shower revealed the capability of the Indian MST radar to record large numbers of meteor trails. The distribution of radio meteor trails due to a Leonid meteor shower in space and time provided a unique opportunity to construct the height profiles of lower thermospheric temperatures and winds, with good time and height resolution. There was a four-fold increase in the meteor trails observed during the LMS compared to a typical non-shower day. The temperatures were found to be in excellent continuity with the temperature profiles below the radio meteor region derived from the co-located Nd-Yag LIDAR and the maximum height of the temperature profile was extended from the LIDAR to ~110 km. There are, how-ever, some significant differences between the observed profiles and the CIRA-86 model profiles. The first results on the meteor statistics and neutral temperature are presented and discussed below. Key words. Atmospheric composition and structure (pres-sure, density, and temperature) History of geophysics (at-mospheric sciences) Meteorology and atmospheric dynamics (middle atmosphere dynamics
OZONE SIMULATIONS FOR HGB AREA USING DIFFERENT CHEMICAL MECHANISMS WITHCAMX
ABSTRACT Areas with air pollution problems often tend to use sophisticated Air Quality Models (AQM) and thes
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