ABSTRACT
We report a simple but efficient biological route based on the hydrolysis of cellulose to synthesize Ag-Pd alloy nanoparticles (NPs) under hydrothermal conditions. X-ray powder diffraction, ultraviolet-visible spectroscopy and scanning transmission electron microscopy-energy dispersive X-ray analyses were used to study and demonstrate the alloy nature. The microscopy results showed that well-defined Ag-Pd alloy NPs of about 59.7 nm in size can be biosynthesized at 200 °C for 10 h. Fourier transform infrared spectroscopy indicated that, triggered by silver sulfate, cellulose was hydrolyzed into saccharides or aldehydes, which served as both reductants and stabilizers, and accounted for the formation of the well-defined Ag-Pd NPs. Moreover, the as-synthesized Ag-Pd nanoalloy showed high activity in the catalytic reduction of 4-nitrophenol by NaBH4.
ABSTRACT
This study developed an ergonomic evaluation system for the design of high-altitude partial pressure suits (PPSs). A total of twenty-one Chinese males participated in the experiment which tested three types of ergonomics indices (manipulative mission, operational reach and operational strength) were studied using a three-dimensional video-based motion capture system, a target-pointing board, a hand dynamometer, and a step-tread apparatus. In total, 36 ergonomics indices were evaluated and optimized using regression and fitting analysis. Some indices that were found to be linearly related and redundant were removed from the study. An optimal ergonomics index system was established that can be used to conveniently and quickly evaluate the performance of different pressurized/non-pressurized suit designs. The resulting ergonomics index system will provide a theoretical basis and practical guidance for mission planners, suit designers and engineers to design equipment for human use, and to aid in assessing partial pressure suits.
Subject(s)
Ergonomics/methods , Gravity Suits , Joints/physiology , Protective Clothing , Task Performance and Analysis , Aircraft , China , Equipment Design , Hand Strength , Humans , Male , Movement/physiology , Range of Motion, Articular , Video Recording , Young AdultABSTRACT
Pt nanoparticles (PtNPs) were biologically synthesized by reducing Na2PtCl4 with Cacumen Platycladi Extract (CPE). The effects of reaction temperature, initial Pt(II) concentration, and CPE percentage on Pt(II) conversion and the size distribution of the PtNPs were studied. The results showed that the Pt(II) conversion rate reached 95.9% and that PtNPs measuring 2.4±0.8nm were obtained under the following conditions: reaction temperature, 90°C; CPE percentage, 70%; initial Pt(II) concentration, 0.5mM; reaction time, 25h. In addition, the bioreduction of Pt(II) was attributed to reducing sugars and flavonoids rather than proteins. The elucidation of bioreductive mechanism of Pt(II) ions was achieved by investigating the changes that occurred in the reducing sugar, flavonoid and protein concentrations in the plant extract, leading to a good insight into the formation mechanism of such biosynthesized PtNPs.
Subject(s)
Cupressaceae/metabolism , Metal Nanoparticles/chemistry , Plant Extracts/metabolism , Platinum/chemistry , Chlorides/chemistry , Drugs, Chinese Herbal , Oxidation-Reduction , Particle Size , Platinum Compounds/chemistryABSTRACT
Partial pressure suits (PPSs) are used under high altitude, low-pressure conditions to protect the pilots. However, the suit often limits pilot's mobility and work efficiency. The lack of ergonomic data on the effects of PPSs on mobility and performance creates difficulties for human factor engineers and cockpit layout specialists. This study investigated the effects of PPSs on different ergonomic mobility and performance indices in order to evaluate the suit's impact on pilot's body mobility and work efficiency. Three types of ergonomics indices were studied: the manipulative mission, operational reach and operational strength. Research results indicated that a PPS significantly affects the mobility and operational performance of the wearers. The results may provide mission planners and human factors engineers with better insight into the understanding of pilots' operational function, mobility and strength capabilities when wearing PPS.
