3,017 research outputs found
Where Will All the Waste Go?: Utilizing Extended Producer Responsibility Framework Laws to Achieve Zero Waste
The United States has a waste problem. It represents only five percent of the world population, yet it generates twenty-five to thirty percent of the world’s waste. In 2008, the United States generated 389.5 million tons of municipal solid waste (MSW). As our economy and population continue to grow, our waste will continue to grow as well. The obvious dilemma is that all of this waste, the byproduct of our economic advances, creates significant adverse environmental and public health effects when landfilled or incinerated.
This Article explores the use of extended producer responsibility (EPR) laws to achieve the ultimate waste management goal: “zero waste.” Zero waste is achieved through the complete diversion of MSW from landfills and incinerators, resource conservation, and sustainable product redesign. Historically, MSW has been dumped in landfills or deposited in waste incinerators, practices that have allowed for robust commerce and economic growth. However, these typical waste management practices cause vast amounts of air, water, and soil pollution, increased greenhouse gas emissions, and other adverse environmental and public health issues associated with burying or burning our garbage
A Physical Model for Drain Noise in High Electron Mobility Transistors: Theory and Experiment
We report the on-wafer characterization of -parameters and microwave noise
temperature () of discrete metamorphic GaAs high electron mobility
transistors (HEMTs) at 40 K and 300 K over a range of drain-source voltages
(). From these data, we extract a small-signal model and the drain
noise temperature () at each bias and temperature. We find that
follows a superlinear trend with at both temperatures. These trends
are interpreted by attributing drain noise to a thermal component associated
with the channel resistance and a component due to real-space transfer (RST) of
electrons from the channel to the barrier [1]. In the present devices at the
minimum , RST contributes % of the drain noise at cryogenic
temperatures. At 300 K, the contribution increases to over % of the
total drain noise. This finding indicates that improving the confinement of
electrons in the quantum well could enable room-temperature receivers with up
to % lower noise temperatures by decreasing the contribution of RST to
drain noise.Comment: 6 pages, 6 figure
Advancing Nucleosynthesis in Self-consistent, Multidimensional Models of Core-Collapse Supernovae
We investigate core-collapse supernova (CCSN) nucleosynthesis in polar
axisymmetric simulations using the multidimensional radiation hydrodynamics
code CHIMERA. Computational costs have traditionally constrained the evolution
of the nuclear composition in CCSN models to, at best, a 14-species
-network. Such a simplified network limits the ability to accurately
evolve detailed composition, neutronization and the nuclear energy generation
rate. Lagrangian tracer particles are commonly used to extend the nuclear
network evolution by incorporating more realistic networks in post-processing
nucleosynthesis calculations. Limitations such as poor spatial resolution of
the tracer particles, estimation of the expansion timescales, and determination
of the "mass-cut" at the end of the simulation impose uncertainties inherent to
this approach. We present a detailed analysis of the impact of these
uncertainties on post-processing nucleosynthesis calculations and implications
for future models.Comment: Proceedings of the 13th Symposium on Nuclei in the Cosmos. 7-11 July
2014. Debrecen, Hungar
Making Sense of Hip Preservation Procedural Coding--Getting Paid for Your Work!
Hip preservation and peri-trochanteric procedures are becoming more commonplace for the arthroplasty surgeon. Understanding the reimbursement for these procedures remains a challenge for those looking to expand this portion of their practice. In order to financially maximize the surgeon’s efforts, we present recommendations for hip preservation procedural coding
Patient characteristics associated with screening positive for Alzheimer's disease and related dementia
Introduction:
Screening all older adults for Alzheimer's disease and related dementias (ADRD) in primary care may not be acceptable or feasible. The goal of this study was to identify factors that could optimize screening in primary care and enhance its feasibility.
Methods:
This is a cross-sectional study in rural, suburban, and urban primary care practices in Indiana. A total of 1,723 patients ≥65 years of age were screened for ADRD using the Memory Impairment Screen. Logistic regression was used to identify patient-specific factors associated with screening positive for ADRD.
Results:
The positive screening rate was 4.9%. Rates varied significantly across the three study sites. The rural site had the lowest rate (2.8%), which was significantly lower than the rates at the suburban (5.6%) and urban (6.6%) sites (P<0.01). Patient age, sex, and education were significantly (P<0.05) associated with screening positive for ADRD.
Conclusion:
Targeted screening of patients at risk for ADRD may represent a more optimal and feasible screening alternative to population screening
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