Nitric Oxide Emissions from Engineered Soil Systems

Sophisticated laboratory equipment and procedures are developed and used in controlled experiments to measure nitric oxide (NO) emissions ranging from 42 to 75 ng N∕m2?s from sludge-amended soil of concern to environmental engineers because nitric oxide emitted to the troposphere is a precursor to troublesome ozone formation and also of concern to agricultural engineers because valuable nitrogen as fertilizer is lost from the soil. Water-filled pore space is confirmed to be of critical importance to NO flux, and the upper layers of soil are determined to contribute the larger portion of the NO fluxing from the soil to the troposphere. More than 42% of the total NO flux comes from the top 1 cm of soil, with NO contributions decreasing exponentially with soil depth and very little if any tropospheric NO contributed from soil at a depth of 20 cm or greater. The results are discussed in terms of microbiological, chemical, and soil transport processes that influence NO flux from sludge-amended soil.     

Molecular order in spider major ampullate silk (dragline): Effects of spinning rate and post‐spin drawing

Optical birefringence measurements are used to characterize how the molecular order of spider (Nephila clavipes) major ampullate silk is affected by linear spinning rate, by the extent of post‐spin drawing, and by post‐spin drawing rate. Results are interpreted qualitatively in terms of a simple microstructural model, in which birefringence depends on both the overall degree of molecular orientation and the extent to which crystalline regions are present. In contrast to the behavior of conventional, synthetic polymers, birefringence is found to be an unreliable predictor of tensile stiffness: microstructural changes that lead to increased birefringence may leave stiffness unchanged or, in some cases, lower than before. It is unlikely that economic processing of silk‐like polymers into fiber that exhibits biomimetic tensile properties can be achieved with spinning followed by drawing, or with a single spinning step. Instead, spinning followed by thermochemical treatment under load may be needed to obtain the critical combination of molecular orientation and crystallinity in commercially satisfactory time scales. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 895–903, 1999     

Finite element analysis of orifice-compensated hydrostatic journal bearings

The steady state performence of an orifice compensated hydrostatic journal bearing is analyzed by the finite element method. Performance data have been computed. for a four-pocket bearing, with various design parameters and eccentricity ratios. It is found that load capacity varies significantly with changes in these parameters.     

Animal research in psychology: Declining or thriving?

From Dialog's PsycINFO database the number of studies with 6 species reported in the Psychological Abstracts was calculated for each year from 1967 to 1988. Also, the number of studies with an additional 11 species were calculated for each year from 1973 to 1988. A hand search in the Journal of the Experimental Analysis of Behavior and Learning and Motivation was also conducted to explore trends in studies on 12 species from 1970 to 1987. The numbers of studies on many species (e.g., baboons, bats, chimpanzees, dolphins, gerbils, guinea pigs, gorillas, hamsters, lemurs, mice, pigeons, rats, seals, and snakes) have remained stable. There has, however, been a steady decline in the numbers of studies on selected species (e.g., cats, dogs, and rabbits). Possible reasons for changing trends in studies on selected species include: increased costs, the cognitive emphasis in psychology, and arguably, animal rights activism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Support levels of psychology departments offering graduate programs in 1969-1970.

Conducted a 2nd annual survey of psychology departments having graduate programs, with 152 departments responding. Comparative data were obtained on 28 variables related to budgetary and personnel support characteristics of the departments (faculty salary, departmental budgets, support personnel, student/faculty ratios, etc.). Data were analyzed in terms of geographic regions, type of institution (private vs. Public), size of university, and type of graduate degree programs offered (master's degree only vs. Doctoral degree). Data show both discriminable differences among universities on some variables and wide variability. The survey results may provide (a) a comparative base for departmental chairmen, students examining graduate programs, candidates interviewing for academic positions, and accrediting agencies; and (b) a base line for further annual studies to reflect changes in support of higher education. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Taking a count: the evaluation of genetic testing

While some forms of genetic testing have been available for decades, the progress of the Human Genome Project will expand the possibilities for testing. Evaluation of genetic testing is warranted because health care services have an opportunity cost and thus the benefits of testing must be assessed against the costs. However, genetic testing raises new methodological difficulties in taking into account the full range of costs, benefits and risks. The conventional approach to evaluating new technologies is to assess their benefits in terms of health outcomes only, and to consider the effects on the individuals being tested. Like any test, the product of genetic testing is information. Any subsequent health outcome gain depends on the effectiveness of any intervention which results from the information. Assessing the benefits in terms of health outcomes only excludes consideration of any value, both positive and negative, attached to information. The special feature of genetic testing is that the information obtained has implications for family members. This information may have value to relatives individually and may affect family interactions. Information also has value at a social level; it may affect social relationships and interactions. As the possibilities for genetic testing expand, it is likely that testing programs will be subject to economic evaluation. Until the methods and measures used can validly take this range of effects into account (and into a count of benefits), then the results of evaluation studies will be, at best, incomplete and, at worst, misleading.     

Photovoltaic device performance of single-walled carbon nanotube and polyaniline films on n-Si: device structure analysis

In this paper, we explore the use of two organic materials that have been touted for use as photovoltaic (PV) materials: inherently conducting polymers (ICPs) and carbon nanotubes (CNTs). Due to these materials' attractive features, such as environmental stability and tunable electrical properties, our focus here is to evaluate the use of polyaniline (PANI) and single wall carbon nanotube (SWNT) films in heterojunction diode devices. The devices are characterized by electron microscopy (film morphology), current-voltage characteristics (photovoltaic behavior), and UV/visible/NIR spectroscopy (light absorption). We have found that both PANI and SWNT can be utilized as photovoltaic materials in a simple bilayer configuration with n-type Silicon: n-Si/PANI and n-Si/SWNT. It was our aim to determine how photovoltaic performance was affected utilizing both PANI and SWNT layers in multilayer devices: n-Si/PANI/SWNT and n-Si/SWNT/PANI. The short-circuit current density increased from 4.91 mA/cm(2) (n-Si/PANI) to 12.41 mA/cm(2) (n-Si/PANI/SWNT), while an increase in power conversion efficiency by ~91% was also observed. In the case of n-Si/SWNT/PANI and its corresponding device control (n-Si/SWNT), the short-circuit current density was decreased by an order of magnitude. The characteristics of the device were affected by the architecture and the findings have been attributed to the more effective transport of holes from the PANI to SWNT and less effective transport of holes from PANI to SWNT in the respective multilayer devices.     

Developmental switching in the parasitic nematode Strongyloides ratti

Strongyloides ratti is a nematode parasite of rats. It is able to undergo two types of development outside the host: heterogonic (free-living adults and sexual reproduction) and homogonic (direct larval development). Homogonic development has a number of similarities with the development of the dauer stage of free-living nematodes, including Caenorhabditis elegans. Using isofemale lines of the parasite, factors that control this developmental choice have been investigated. Isofemale lines can be selected for both heterogonic and homogonic development, but are still able to respond to environmental conditions. By using temperature shift experiments it has been possible to determine when larvae become developmentally committed. All larvae are developmentally committed after 24 h at 19 degrees C.