Toward Low-Cost,High-Energy Density,and High-Power Density Lithium-Ion Batteries

Reducing cost and increasing energy density are two barriers for widespread application of lithium-ion batteries in electric vehicles. Although the cost of electric vehicle batteries has been reduced by ~70% from 2008 to 2015, the current battery pack cost ($268/kWh in 2015) is still >2 times what the USABC targets ($125/kWh). Even though many advancements in cell chemistry have been realized since the lithium-ion battery was first commercialized in 1991, few major breakthroughs have occurred in the past decade. Therefore, future cost reduction will rely on cell manufacturing and broader market acceptance. This article discusses three major aspects for cost reduction: (1) quality control to minimize scrap rate in cell manufacturing; (2) novel electrode processing and engineering to reduce processing cost and increase energy density and throughputs; and (3) material development and optimization for lithium-ion batteries with high-energy density. Insights on increasing energy and power densities of lithium-ion batteries are also addressed.     

Day Labourers, Unemployment and Socio-economic Development in South Africa

One of the most visible forms of unemployment is the men who stand at the side of the road or on corners daily, waiting for any job that may come their way. It is estimated that there are nearly 1,000 places in South Africa where a minimum of about 45,000, mostly black African men, stand, waiting to be picked up. The South African space economy is characterised by an uneven distribution of economic activities. International empirical studies have shown that there is a geographical or spatial coincidence between levels of unemployment and levels of gross domestic product per capita. The first objective of this article is to highlight some of the basic demographic dynamics of day labourers. The second is to investigate the spatial distribution of and the relationship between day labourers, unemployment and the general level of socio-economic development in South Africa. Day labourers share a number of common characteristics, but there were also obvious differences in their morale and spirit. The analyses showed that there is also a general spatial coincidence between levels of socio-economic development and the numbers of day labourers in South Africa, with a relatively high correlation coefficient between the two.     

Adolescents' theories about the development of their relationships with parents.

Assessed 100 undergraduates' developmental theories about their affective relationships with their parents, using a retrospective method. Ss used drawings and questionnaire ratings to portray their relationships with parents at 5 points between infancy and the present. From infancy to their current age, Ss portrayed their relationships in 2 major ways: They perceived themselves as gaining in responsibility, dominance, independence, and similarity from infancy to the present, whereas they portrayed their parents as experiencing a decline on these dimensions. For variables indicating closeness and love, however, there was a striking discontinuity in these linear trends: Although Ss perceived linear trends from infancy to adolescence, they depicted their current relationships as involving a great deal more love and closeness. They also portrayed their relationships with mothers and fathers somewhat differently. More responsibility was felt toward the mothers and they were portrayed as especially friendly, but Ss felt more similar to their fathers, whom they perceived as dominant. Results suggest that late adolescents construct theories of the affective components of their relationships with their parents to serve the needs of separation while maintaining a close affective tie to the parents. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Adaptive Control for Robotic Rebar Bending

Abstract: Computers are becoming essential tools for integrating design, planning, fabrication, and construction. Computer-controlled construction equipment is poised to receive information from data generated in the design phase. The robotic execution of construction operations, however, depends on complex models for autonomous and intelligent control. This paper introduces a strategy for the robotic bending of rebar and presents the results of experimental work with an actual testing facility. Mechanical properties and behavior of rebar are examined to develop rules for control. Focus is placed on exploring the dynamics between the bender and steel bars. The concepts of impedance, admittance, and compliance of both the machine and the environment will be discussed in the context of control strategy development.     

Dichlorvos space treatment for protection of packaged flour against insect infestation

Dichlorvos vapor was applied weekly from dichlorvos-impregnated resin pellets into 42·5 m³ (1500 ft³) chambers. The chambers contained insect-free flour packaged in cotton sheeting, and in multiwall paper bags stacked at various distances from similar bags of infested flour. The dichlorvos concentration attained in the chambers from the weekly application of vapor was about 3 μg/1. After 5 months of storage, the number of insects found in the flour indicated that the dichlorvos applications retarded the infestation of flour in cotton bags and prevented the infestation of flour in the multiwall paper bags. Chemical analysis showed that dichlorvos residues were less than 0·1 ppm in the flour and, in general, less than 1·1 μg/dm² (10 μg/ft²) on the packaging materials.     

NO and NO2 emission ratios measured from in-use commercial aircraft during taxi and takeoff

In August 2001, the Aerodyne Mobile Laboratory simultaneously measured NO, NO2, and CO2 within 350 m of a taxiway and 550 m of a runway at John F. Kennedy Airport. The meteorological conditions were such that taxi and takeoff plumes from individual aircraft were clearly resolved against background levels. NO and NO2 concentrations were measured with 1 s time resolution using a dual tunable infrared laser differential absorption spectroscopy instrument, utilizing an astigmatic multipass Herriott cell. The CO2 measurements were also obtained at 1 s time resolution using a commercial non-dispersive infrared absorption instrument. Plumes were measured from over 30 individual planes, ranging from turbo props to jumbo jets. NOx emission indices were determined by examining the correlation between NOx (NO + NO2) and CO2 during the plume measurements. Several aircraft tail numbers were unambiguously identified, allowing those specific airframe/engine combinations to be determined. The resulting NOx emission indices from positively identified in-service operating airplanes are compared with the published International Civil Aviation Organization engine certification test database collected on new engines in certification test cells.     

Distributed Streams Algorithms for Sliding Windows

Massive data sets often arise as physically distributed, parallel data streams, and it is important to estimate various aggregates and statistics on the union of these streams. This paper presents algorithms for estimating aggregate functions over a “sliding window” of the N most recent data items in one or more streams. Our results include: 1. For a single stream,we present the first ε-approximation scheme for the number of 1’s in a sliding window that is optimal in both worst case time and space. We also present the first ε-approximation scheme for the sum of integers in [0..R] in a sliding window that is optimal in both worst case time and space (assuming R is at most polynomial in N). Both algorithms are deterministic and use only logarithmic memory words. 2. In contrast, we show that any deterministic algorithm that estimates, to within a small constant relative error, the number of 1’s (or the sum of integers) in a sliding window on the union of distributed streams requires Ω(N) space. 3. We present the first (randomized) (ε, δ)-approximation scheme for the number of 1’s in a sliding window on the union of distributed streams that uses only logarithmic memory words. We also present the first (ε, δ)-approximation scheme for the number of distinct values in a sliding window on distributed streams that uses only logarithmic memory words. Our results are obtained using a novel family of synopsis data structures called waves.     

Quadrilateral shell element for rotational shells

A doubly curved shell element of quadrilateral shape which is suitable for the analyses of rotational shells is derived. Geometry is defined in a polar coordinate system while displacements are specified in cartesian coordinates. The element is a C° element which includes transverse shear deformations and is intended for modelling shells which follow a circular curve form in one direction.     

Attraction of a free-living nematode, Caenorhabditis elegans, to foodborne pathogenic bacteria and its potential as a vector of Salmonella poona for preharvest contamination of cantaloupe

Caenorhabditis elegans was studied to determine the potential role of free-living microbivorous nematodes as vectors for preharvest contamination of fruits and vegetables with foodborne pathogens. The propensity of C. elegans to be attracted to seven strains of Escherichia coli O157:H7, eight serotypes of Salmonella, six strains of Listeria monocytogenes, and cantaloupe juice was investigated. Twenty to 30 adult worms were placed on the surface of K agar midway between a 24-h bacterial colony and 10 microl of uninoculated tryptic soy broth (TSB) or cantaloupe juice positioned 1.5 cm apart. The numbers of nematodes that migrated to the colony, to the TSB, and to the cantaloupe juice within 5, 10, 15, and 20 min at 21 degrees C were determined, and then the plates were incubated at 37 degrees C for up to 7 days to determine the ability of C. elegans to survive and reproduce in bacterial colonies. The nematode was attracted to colonies of all test pathogens and survived and reproduced within colonies for up to 7 days. C. elegans was not attracted to cantaloupe juice. The potential of C. elegans to serve as a vector for the transport of Salmonella Poona to cantaloupe rinds was investigated. Adult worms that had been immersed in a suspension of Salmonella Poona were deposited 1 or 3 cm below the surface of soil on which a piece of cantaloupe rind was placed. The rind was analyzed for the presence of Salmonella Poona after 1, 3, 7, and 10 days at 21 degrees C. The presence of Salmonella Poona was evident more quickly on rinds positioned on soil beneath which C. elegans inoculated with Salmonella Poona was initially deposited than on rinds positioned on soil beneath which Salmonella Poona alone was deposited. The time required to detect Salmonella Poona on rinds was longer when the rind was placed 3 cm above the inoculum than when the rind was placed 1 cm above the inoculum. Free-living nematodes may play a role in the preharvest dispersal of incidental human pathogens in soil to the surfaces of raw fruits and vegetables in contact with soil during development and maturation, as evidenced by the behavior of C. elegans as a test model.     

A Review of the U.S. Department of Energy's Inertial Fusion Energy Program

This is the final report of a panel set up by the U.S. Department of Energy (DOE) Fusion Energy Sciences Advisory Committee (FESAC) in response to a charge letter from Dr. Ray Orbach (Appendix A). In that letter, Dr. Orbach asked FESAC for an assessment of the present status of inertial fusion energy (IFE) research carried out in contributing programs. These programs include the heavy ion (HI) beam, the high average power laser (HAPL), and Z-Pinch drivers and associated technologies, including fast ignition (FI). This report, presented to FESAC on March 29, 2004, and subsequently approved by them (Appendix B), presents FESAC's response to that charge.