Comparing stationary standing with an intermittent walking posture during assembly operations

The purpose of this investigation was to evaluate two different standing postures, intermittent walking (dynamic) and stationary, on 11 volunteers. While performing the activity in a stationary posture, volunteers worked barefoot for 25 minutes at a particular workstation, taking up to five passive breaks. The dynamic standing postural activity was similar in every respect with the exception of the nature of the breaks that were spent walking from one workstation to the other. Foot pressure was analyzed using a static evaluation variable (contact area) and a dynamic evaluation variable (area pressure change root mean square [aPcrms]). Foot center of pressure (COP) was analyzed using two of its features: excursion length (LEN) and root mean square velocity of excursions (VEL). In addition, a psychophysical study was used to distinguish the comfort levels of various muscles between the two postures. The quantifications of the four physiological variables revealed a lower comfort index (p < 0.05) in stationary standing compared to dynamic standing during assembling duties. This significant distinction was further corroborated by the results of the psychophysical test. Such a positive influence of the dynamic standing posture on standing comfort can be used to improve industrial productivity. © 2008 Wiley Periodicals, Inc.     

An atomic force microscope study of carbon onions and related nanoparticles

Carbon onions are found along with carbon nanotubes and other carbon nanoparticles in the cathodic deposit in the arc-vaporization of graphite. Atomic force microscopy has been used to characterize these particles on the basis of their sizes and shapes. Onion-like particles have three-dimensional, near spherical structure and are distinct from two-dimensional graphitic particles. The spherical shape and height to diameter ratios obtained using atomic force microscope, afford a distinction between onion-like structures and other carbon nanoparticles.     

Formation of dialyzable iron during in-vitro digestion and extraction of mycoprotein

Mycoprotein is the biomass of the fungus Fusarium venenatum. The ability of mycoprotein to enhance production of dialyzable iron following in-vitro digestion or extraction was studied, with the aim of identifying the components responsible. Digested mycoprotein, extracted mycoprotein and digested chicken breast muscle all produced about ten times as much dialyzable iron as the control. All of the dialyzable iron from mycoprotein was ferric. Essentially all the dialyzable iron passed through a 1 kDa molecular weight cut-off membrane. Iron binding components were extracted from mycoprotein using weak acid but not water. Extraction of mycoprotein produced both dialyzable and non-dialyzable components, which bound ferric iron. Analysis of the digests and the dialyzable fraction of acid extraction showed that they contained siderophores, which contributed to the formation of dialyzable iron.     

Nonwetting,nonrolling, stain resistant polyhedral oligomeric silsesquioxane coated textiles

Cotton/polyester fabric surfaces were modified using nanostructured organic‐inorganic polyhedral oligomeric silsesquioxane (POSS) molecules via solution dip coating. Surface wetting characteristics of coatings prepared from two chemically and structurally different POSS molecules, a closed cage fluorinated dodecatrifluoropropyl POSS (FL‐POSS) and an open cage nonfluorinated trisilanolphenyl POSS (Tsp‐POSS), were evaluated with time and compared with Teflon. Surface analysis, including Atomic Force Microscopy, SEM/EDAX, and NMR revealed the presence of POSS aggregates on the fabric surface leading to a spiky topography, high roughness, and hysteresis. POSS coated fabrics showed complete reversal of surface wetting characteristics with contact angles higher than the benchmark Teflon surface. Water contact angle measured as a function of time showed equivalent or better performance for POSS‐coated surfaces in comparison to Teflon. Furthermore, FL‐POSS coated fabric exhibited exceptional stain and acid resistance along with a 38% reduction in relative surface friction. Additionally, “nonsliding” and high surface adhesion behavior of water droplets on the FL‐POSS coated fabric are reported. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Processing,Structure, and Properties of PAN/MWNT Composite Fibers

Conventional dry‐jet wet fiber spinning techniques were used to fabricate continuous PAN/MWNT composite fibers with up to 20 wt.‐% nanotube loading. PAN at the MWNT interface exhibited lower solubility under thermodynamically favorable conditions than in bulk PAN, indicating good interfacial interaction. Due to the PAN/MWNT interaction at the interface, thermal shrinkage decreases with increasing MWNT loading (5 to 20 wt.‐%). For high MWNT loadings, PAN/MWNT composite fiber at 15 wt.‐% MWNT loading showed an axial electrical conductivity of 1.24 S · m^?1. For all loadings, PAN/MWNT composite fibers exhibited higher tensile moduli than theoretically predicted by rule‐of‐mixture calculations, suggesting good reinforcement of the PAN by MWNT.

     

Use of genetic algorithms to develop an adaptive fuzzy logic controller for a cooling coil

An adaptive approach to control a water valve for a cooling coil, called an adaptive fuzzy logic controller (AFLC), is developed and validated in this study. The AFLC calculates the error between the supply air temperature and the supply air temperature set point for air in an air handling unit (AHU) of a heating, ventilating, and air conditioning (HVAC) system and continues to improve the fuzzy controller parameters to minimize the error. The AFLC uses genetic algorithms (GAs) to improve the fuzzy rule matrix and fuzzy membership functions for the AHU in HVAC systems. In this paper, the application of genetic algorithms for developing the AFLC is presented. After a brief background on fuzzy logic controllers and GA theory, the use of GAs is explained. Three methods of modifying the fuzzy rule matrix using the GAs are presented along with simulation and real-time experimental results. Experimental results indicate that GAs can be successfully applied to modify an AFLC rule matrix to achieve a better controller.     

Performance Assessment of a New Radiation Microsensor Based 4H-SiC trench MOSFET: A Simulation Study

Silicon - The MOSFET has been widely used as a detector for high-energy radiations in areas like nuclear energy and medical treatments. Generally, the shift in threshold voltage of the...     

When false recognition is unopposed by true recognition: Gist-based memory distortion in Alzheimer's disease.

The authors examined false recognition of semantic associates in patients with probable Alzheimer's disease (AD), older adults, and young adults using a paradigm that provided rates of false recognition after single and multiple exposures to word lists. Using corrected false recognition scores to control for unrelated false alarms, the authors found that (a) the level of false recognition after a single list exposure was lower in AD patients than in controls; (b) across 5 trials, false recognition increased in AD patients, decreased in young adults, and showed a fluctuating pattern in older adults; and (c) all groups showed an increase in true recognition over the 5 trials. Analyses suggested that AD patients built up semantic gist across trials, whereas both control groups were able to use increased item-specific recollection and more conservative response criteria to suppress gist-based false alarms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)