Homogeneous Gold Catalysis through Relativistic Effects: Addition of Water to Propyne

In the catalytic addition of water to propyne the Au(III) catalyst is not stable under non-relativistic conditions and dissociates into a Au(I) compound and Cl2. This implies that one link in the chain of events in the catalytic cycle is broken and relativity may well be seen as the reason why Au(III) compounds are effective catalysts.Comment: 12 pages, 3 figures, 1 tabl

Development of Graphene Nanoplatelets Reinforced Shape Memory Polyurethane and Their DMA Studies

Shape memory nanocomposites have been synthesized using ether type shape memory polyurethane (SMPU) and graphene nanoplatelets (GNPs). A twin screw co-rotating microcompounder with a back flow channel has been employed to ensure proper dispersion of GNPs in the polymer matrix. Four compositions of GNPs in SMPU have been prepared. Morphology of fractured nanocomposites reveals uniform dispersion of graphene in SMPU. The dynamic-thermo-mechanical properties of nanocomposites at 0.1 and 10 Hz have been studied. Addition of 1 phr GNPs increases storage modulus of SMPU from 2.8 to 3.73 GPa and the value of tan δ peak has been decreased from 0.81 to 0.53. The GNPs in SMPU matrix influence shape recovery which improves with the addition of GNPs with in experimental range

Role of the dielectric constant of ferroelectric ceramic in enhancing the ionic conductivity of a polymer electrolyte composite

The dispersal of high dielectric constant ferroelectric ceramic material Ba(0.7)Sr(0.3)TiO(3) (Tc~30 C) and Ba(0.88)Sr(0.12)TiO(3) (Tc~90 C) in an ion conducting polymer electrolyte (PEO:NH4I) is reported to result in an increase in the room temperature ionic conductivity by two orders of magnitude. The conductivity enhancememt "peaks" as we approach the dielectric phase transition of the dispersed ferroelectric material where the dielectric constant changes from ~ 2000 to 4000. This establishes the role of dielectric constant of the dispersoid in enhancing the ionic conductivity of the polymeric composites.Comment: 10 pages, 2 figure

Development of Nano SiO2 Particles Dispersed Shape Memory Epoxy Composites

Thermo responsive shape memory epoxy based composites are being investigated for their excellent mechanical and thermal properties. In present study the thermosetting epoxy containing different composition of SiO2 nano particles ranging from 1 to 4 wt. % have been prepared through solvent casting route. Developed composites have been studied for grain analysis, FTIR, shape recovery, impact strength and hardness. Addition of 3 wt. % SiO2 improves hardness and impact strength significantly. Average grain size of SiO2 particles increase at higher wt. % of SiO2 in polymer matrix due to agglomeration of nanoparticles

Disability, physical activity, and health-related quality of life in Australian adults: An investigation using 19 waves of a longitudinal cohort.

BACKGROUND: Any form of long-term physical or mental impairment might negatively influence health-related quality of life (HRQoL). HRQoL, as an independent concept, covers a wide range of characteristics that includes physical, mental, social, and spiritual functions. People with disabilities are continuously exposed to multiple barriers that deteriorate their HRQoL. It also creates impairment in performing physical activities. However, experts opine regular physical exercise as an intervention to help disabled people. This research aims to investigate the association between disability and physical activity with HRQoL among the adult population in Australia. DESIGN: A retrospective cohort study. METHODS: This study utilized the most recent 19 waves of data (2002-2020) from the nationally representative Household, Income and Labour Dynamics in Australia (HILDA) survey. Component summary scores such as physical component summary (PCS) and mental component summary (MCS), and SF-6D utility scores were utilized to measure HRQoL. Random-effects GLS regression technique was fitted to estimate the association between disability and physical activity with HRQoL, after adjusting for a range of socio-demographic and health-related characteristics. RESULTS: Disability was negatively associated with the PCS (-5.95), MCS (-2.70) and SF-6D (-0.060) compared with non-disabled counterparts. However, respondents engaged in the recommended level of physical activity had substantial gain in PCS (b = 0.96), MCS (1.57), and SF-6D (0.021) scores. Besides, the results showed that performing the recommended level of physical activity in the presence of disability has lessen the negative effect of disability/ positive moderating effect of physical activity on PCS, MCS, and SF-6D scores by 1.84 points, 0.82 points, and 0.013 percentage points, respectively. CONCLUSION: This study found an inverse association between disability and HRQoL among Australian adults. However, physical activity was associated with improved HRQoL. Therefore, public health interventions, such as the orientation of physical activities, have a higher potential to dwindle the burden regarding HRQoL

Microstructure and Microhardness Study of Aluminium Graphene Composite Made by Laser Additive Manufacturing

Laser additive manufacturing (LAM) is one of the advanced manufacturing technologies capable of manufacturing complex engineering components with superior material properties by layer by layer deposition of material directly from CAD model. Layer-by-layer addition of material empowers LAM in selective deposition of pre-defined composition of material shaping the engineering components making it a feature based design and manufacturing technology. The LAM built components largely depends on LAM processing parameters and the quality of single deposited layer. Hence selection of appropriate processing parameters is one of the mandatory requirements for achieving superior mechanical properties LAM built components. This paper reports the LAM of aluminium/grapheme (Al-G) composite on Al and SS substrate. 2 kW fibre laser based additive manufacturing with 2 mm laser beam diameter at substrate was used to deposit Al-G layers (Al + 1%wt G) at different combinations of laser scanning speed and laser power. Effect of laser power and scanning speed on the quality of deposited layers was investigated oand optimum parametric window was identified. The Optimum range of energy intensity is 50 to 400 J/mm which favours material deposition (< 50P/v - < 400 J/mm). Thus prepared samples were subjected to optical microscopy, scanning electron microscopy and microhardness measurements. A good quality continuous track is observed at 108 J/mm energy intensity and there is very slight change in hardness observed on Al substrate). A significant increase in micro hardness is observed on SS substrate. The maximum value of HV is 463.6 at 0.6 m/min. laser scanning speed and 1.2 kW laser power. These LAM built Aluminium grapheme composite have potential applications in the field of light weight and high strength material for manufacturing of complex shape and cellular structure

A Detailed Cloud Fraction Climatology of the Upper Indus Basin and Its Implications for Near-Surface Air Temperature*

implications for near surface air temperature. Journal of Climate 2015, 28(9)

Reactivity of Gold Hydrides: O2 Insertion into the Au–H Bond

Dioxygen reacts with the gold(I) hydride (IPr)AuH under insertion to give the hydroperoxide, (IPr)AuOOH, a long-postulated reaction in gold catalysis and the first demonstration of O2 activation by Au-H in a well-defined system. Subsequent condensation gave the peroxide (IPr)Au-OO-Au(IPr) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene). The reaction kinetics are reported, as well as the reactivity of Au(I) hydrides with radical scavengers