Acceleration effects of microbial inoculum on palm oil mill organic waste composting.

ABSTRACT The acceleration effects of inoculum in composting of empty fruit bunches were investigated. Composting of empty fruit bunches fibres in two sizes, 4 cm and 2 cm length, were treated with microbial inoculum consisting of Agromonas, Aspergillus, Azotobacter, Bacillus, Celhdomonas, Chaetomium, Clostridium, Coprinus, Microbispora, Penicillium, Pseudomonas, Thermoactinomyces, Trichoderma and Trichurus in separate laboratory scale in-vessel of 30 liters volume. A control without inoculum with 4 cm length empty fruit bunches was also conducted in parallel. The compost piles were shift-turned weekly. Parameters such as moisture content, temperature, pH, and electrical conductivity were used to monitor the composting processes. The carbon-nitrogen ratio, UV-vis spectrophotometer test, and germination test were used to assess the maturity of compost. The results showed that the inoculum was effective in reducing the C/N ratio by 54% compared to control 46% and rapidly increasing the UV-vis absorption ratio in first three weeks. By using functional microbes, the composting of empty fruit bunches was reduced to 5 weeks compared to 9 weeks for those without inoculation. The acceleration effect was more prominent for the 2 cm length samples

Growth rate of YBCO single grains containing Y-2411(M)

Y-Ba-Cu-O (YBCO) single grains have the potential to generate large trapped magnetic fields for a variety of engineering applications, and research on the processing and properties of this material has attracted world-wide interest. In particular, the introduction of flux pinning centres to the large grain microstructure to improve its current density, Jc, and hence trapped field, has been investigated extensively over the past decade. Y 2Ba4CuMOx [Y-2411(M)], where M = Nb, Ta, Mo, W, Ru, Zr, Bi and Ag, has been reported to form particularly effective flux pinning centres in YBCO due primarily to its ability to exist as nano-size inclusions in the superconducting phase matrix. However, the addition of the Y-2411(M) phase to the precursor composition complicates the melt-processing of single grains. We report an investigation of the growth rate of single YBCO grains containing Y-2411(Bi) phase inclusions and Y2O3. The superconducting properties of these large single grains have been measured specifically to investigate the effect of Y2O3 on broadening the growth window of these materials

Enhancement of Transition Temperature in FexSe0.5Te0.5 Film via Iron Vacancies

The effects of iron deficiency in FexSe0.5Te0.5 thin films (0.8<x<1) on superconductivity and electronic properties have been studied. A significant enhancement of the superconducting transition temperature (TC) up to 21K was observed in the most Fe deficient film (x=0.8). Based on the observed and simulated structural variation results, there is a high possibility that Fe vacancies can be formed in the FexSe0.5Te0.5 films. The enhancement of TC shows a strong relationship with the lattice strain effect induced by Fe vacancies. Importantly, the presence of Fe vacancies alters the charge carrier population by introducing electron charge carriers, with the Fe deficient film showing more metallic behavior than the defect-free film. Our study provides a means to enhance the superconductivity and tune the charge carriers via Fe vacancy, with no reliance on chemical doping.Comment: 15 pages, 4 figure

Effect of PVA doping on flux pinning in Bulk MgB2

The synthesis and characterization of PVA (Poly Vinyl Acetate) doped bulk MgB2 superconductor is reported here. PVA is used as a Carbon source. PVA doping effects made two distinguishable contributions: first enhancement of Jc field performance and second an increase in Hc2 value, both because of carbon incorporation into MgB2 crystal lattice. The susceptibility measurement reveals that Tc decreased from 37 to 36 K. Lattice parameter a decreased from 3.085 A to 3.081 A due to the partial substitution of Carbon at Boron site. PVA doped sample exhibited the Jc values greater than 10^5 A/cm2 at 5 & 10 K at low fields; which is almost 3 times higher than the pure one, while at high fields the Jc is increased by an order of magnitude in comparison to pure MgB2. From R(T)H measurements we found higher Tc values under magnetic field for doped sample; indicating an increase in Hc2. Also the magnetization measurements exhibited a significant enhancement in Hirr value. The improved performance of PVA doped MgB2 can be attributed to the substitution of carbon at boron site in parent MgB2 and the resulting impact on the carrier density and impurity scattering. The improved flux pinning behavior could easily be seen from reduced flux pinning force plots.Comment: 14 Pages of Text + Figs. To appear in Physica

Magnetic field processing to enhance critical current densities of MgB2 superconductors

Magnetic field of up to 12 T was applied during the sintering process of pure MgB2 and carbon nanotube (CNT) doped MgB2 wires. We have demonstrated that magnetic field processing results in grain refinement, homogeneity and significant enhancement in Jc(H) and Hirr. The Jc of pure MgB2 wire increased by up to a factor of 3 to 4 and CNT doped MgB2 by up to an order of magnitude in high field region respectively, compared to that of the non-field processed samples. Hirr for CNT doped sample reached 7.7 T at 20 K. Magnetic field processing reduces the resistivity in CNT doped MgB2, straightens the entangled CNT and improves the adherence between CNTs and MgB2 matrix. No crystalline alignment of MgB2 was observed. This method can be easily scalable for a continuous production and represents a new milestone in the development of MgB2 superconductors and related systems

Socioeconomic Patterns of COVID-19 Clusters in Low-Incidence City, Hong Kong

Although coronavirus disease (COVID-19) outbreaks have been relatively well controlled in Hong Kong, containment remains challenging among socioeconomically disadvantaged persons. They are at higher risk for widespread COVID-19 transmission through sizable clustering, probably because of exposure to social settings in which existing mitigation policies had differential socioeconomic effects

Socioeconomic inequality in mental well-being associated with COVID-19 containment measures in a low-incidence Asian globalized city

The COVID-19 pandemic exposes and amplifies pre-existing inequalities even in places with relatively well-controlled outbreaks such as Hong Kong. This study aimed to explore whether the socioeconomically disadvantaged fare worse via various types of worry in terms of their mental health and well-being. Between September and October 2020, 1067 adults in Hong Kong were recruited via a cross-sectional population-wide telephone survey. The inter-relationship between deprivation, types of worry, mental health disorders, and subjective well-being was assessed using structural equation modelling. Results showed significant total effects of deprivation on worries about being infected (p = 0.002), economic activities and livelihood (p < 0.001), and personal savings (p < 0.001), as well as mental health disorders (p < 0.001) and subjective well-being (p < 0.001). Specifically, worry about economic activities and livelihood partly mediated the total effect of deprivation on mental health disorders (p = 0.004), whereas worry about personal savings and worry about economic activities and livelihood partially mediated the total effect of deprivation on subjective well-being (p = 0.007 and 0.002, respectively). Socioeconomic inequality, particularly in mental health and well-being, could be exacerbated via people’s economic concerns during the pandemic, which was largely induced by the COVID-19 containment measures rather than the pandemic per se given the relatively low COVID-19 incidence in Hong Kong

The mediating role of individual-level social capital among worries, mental health and subjective well-being among adults in Hong Kong during the COVID-19 pandemic

The COVID-19 pandemic has substantially induced worries and affected individual mental health and subjective well-being. Nonetheless, a high level of social capital could potentially protect individuals who suffer from mental health problems and thus promote their subjective well-being, especially under the social distancing policies during the pandemic. To this end, based on a random sample of 1053 Hong Kong adults, structural equation modeling was applied to study the path relationships between the worries of COVID-19, social capital, mental health problems, and subjective well-being. The study found that worries during the pandemic were associated with mental health and subjective well-being, through social capital as a mediator. Moreover, social capital exhibited a stronger influence on mental health and subjective well-being in the economically inactive group than in the economically active group. This study highlights the important role of social capital during the COVID-19 pandemic. While Hong Kong’s COVID-19 response has primarily focused on disease prevention, it must be noted that social services and mutual-help activities are also crucial for people to withstand the crisis