Heat-producing elements in the lunar mantle: Insights from ion microprobe analyses of lunar pyroclastic glasses

We provide new estimates for the abundance of heat-producing elements in the lunar mantle by using SIMS techniques to measure the concentrations of thorium and samarium in lunar pyroclastic glasses. Lunar pyroclastic glasses are utilized in this study because they represent quenched products of near-primary melts from the lunar mantle and as such, they provide compositional information about the mantle itself. Thorium and samarium were measured because: (1) Th is not significantly fractionated from Sm during partial melting of the pyroclastic glass source regions, which are dominated by olivine and pyroxene. Therefore, the Th/Sm ratios that we measure in the pyroclastic glasses reflect the Th/Sm ratio of the pyroclastic glass source regions. (2) Strong correlations between Th, U, and K on the Moon allow us to use measured Th concentrations to estimate the concentrations of U and K in the pyroclastic glasses. (3) Th, Sm, U, and K are radioactive elements and as such, their concentrations can be used to investigate heat production in the lunar mantle.The results from this study show that the lunar mantle is heterogeneous with respect to heat-producing elements and that there is evidence for mixing of a KREEP component into the source regions of some of the pyroclastic glasses. Because the source regions for many of the glasses are deep (?400 km), we propose that a KREEP component was transported to the deep lunar mantle. KREEP enriched sources produce 138% more heat than sources that do not contain KREEP and therefore, could have provided a source of heat for extended periods of nearside basaltic magmatism. Data from this study, in conjunction with models for the fractional crystallization of a lunar magma ocean, are used to show that the average lunar mantle contains 0.15 ppm Th, 0.54 ppm Sm, 0.039 ppm U, and 212 ppm K. This is a greater enrichment in radiogenic elements than some earlier estimates, suggesting a more prolonged impact of radiogenic heat on nearside basaltic volcanism.     

Evaluation of twenty four new Gossypium hirsutum strains for growth, yield, fibre quality and ClCuV resistance under environment of Punjab, Pakistan

Twenty four new strains were tested for their yield, quality and Leaf Curl Virus (ClCuV) resistance. NIAB-111/S, NIAB-98 and NIAB-999 were significantly high fruit bearing varieties at 90 days completing 59.54, 48.26 and 46.00% fruiting respectively. Seed cotton yield of VH-142 was highest with 5417 kgha^?1 and 52 per plant boll bearing, DNH-57 and NIAB-999 remained second and third with 5234 and 5095 kg ha^?1 seed cotton yield, respectively. BH-160 and CRIS-467 were found to be second and third highest boll bearing varieties with 50.97 and 40.20 per plant average bolls respectively. Plant height in CRIS-467, MNH-642 and SLH-224 was significantly higher in comparison to other varieties.NIAB-98, CIM-499 and CIM-506 were found short stature varieties in comparison with other but out of these NIAB-98 and CIM-506 were in high yielding position and CIM-499 was found medium yielder variety. GOT% of MNH-642 remained highest having value of 45.00%. While GOT%. of NIBGE-1, CRIS-168 and CRIS-467 was at lowest position with 35.73, 35.89 and 36.62% respectively. NIAB-111, CIM-499 and BH-160 were at first position in terms of fibre fineness with micronaire values 3.98, 4.00 and 4.07 ìg/inch having fibre length 28.53, 31.38 and 30.23 mm respectively. Out of 26 varieties, 16 varieties resulted maturity index in the range of 85.03% and 90.30% with highest maturity index in case of NIBGE-1 (i.e. 90.30%) followed by NIAB-999 and MNH-642 with 89.55 and 85.5% respectively.CRIS-168, CRIS-468 and CRIS-467 were found viral susceptible.     

Determination of adsorption efficiency based on cation exchange capacity related to red earth, bone meal and pulverised fly ash as ameliorants to lead contaminated soils

Efficient treatment strategies to reduce the toxicity of metal contaminated soil using cost effective techniques such as naturally available ameliorants and industrial waste have emerged. Three easily available amendments were determined: Bone meal, red earth/mud and pulverised fly ash (PFA). The application of ameliorants offered a possible alternative in situ remediation of contaminated sites without disruption to the ecosystem profile. In comparison to other ameliorants Red earth/mud was found to be efficient in intercepting lead leaching from soil amended with different lead compounds based on CEC (Cmol/g). This was associated with the heterogeneous adsorbency principle in red mud which is associated with its ability to bind metal ions (M²⁺) onto one or two types of surface sites at pH< 6.0. However areas that need to be studied and assessed (for public health concerns) critically for wide spread application of all the ameliorants include off-site effects of the ameliorants.     

Removal of airborne hexavalent chromium mist using chitosan gel beads as a new control approach

Airborne hexavalent chromium is a known human respiratory carcinogen and allergen. Many workers are exposed to hexavalent chromium in various processes which chromium electroplating plants are the most common. In this study, the feasibility of a new control approach to remove this pollutant using chitosan beads as a biosorbent was investigated. Hexavalent chromium sorption was studied relative to pH, pollution concentration, sorbent concentration, temperature, and air velocity using one factor at a time approach and Taguchi experimental design. Polluted air with different chromium mist concentrations (10–5000 μg/m³) was contacted to chitosan beads (3.3–20 g/L), floating in distilled water with adjusted pH (3–7), using an impinger at different temperatures (20 and 35 °C), and various velocities (1.12 and 2.24 m/s). The ANOVA test result showed that, there were statistical significant differences between factor levels except optimized pH levels. The higher ions removal efficiencies were achieved at lower levels of air velocities, pollution concentrations, and higher levels of solution pH values, temperatures, and sorbent concentrations.     

Rectangular tank surface aerators: scale up criteria and energy conservation

Surface aeration experiments were conducted in two types of rectangular tanks of aspect ratios i.e., length to width ratio (L/W) of 1.5 and 2 and developed simulation equations to correlate the oxygen transfer coefficient, k and power number, P₀ with a parameter governing theoretical power per unit volume X. The parameter X is defined as equal to F^4/3R^1/3, where F and R are impellers’ Froude and Reynolds numbers respectively). Results have shown that the P₀ can not be simulated singularly with either Reynolds number, R or Froude number, F, which results in scale-effects; there appears to be a need to incorporate the effects of both F and R. It was found that P⁰ is uniquely related to X for rectangular aeration tanks of both aspect ratios, however, such relationships are different depending upon the aspect ratios. It has been demonstrated that energy can be saved substantially if the aeration tanks are run at relatively higher input powers. It is also demonstrated that smaller sized tanks are more energy conservative and economical when compared to big sized tanks, while aerating the same volume of water, and at the same time by maintaining a constant input power in all the tanks irrespective of their size.     

Slow arsenic poisoning of the contaminated groundwater users

This paper gives impact of Arsenic contaminated water on human health as well as overview of the extent and severity of groundwater arsenic contamination in Bangladesh. Scalp hair is the most important part of the human body to monitor the accumulation of this type of poison. Therefore, an experiment has been carried out by Neutron Activation Analysis (NAA) at Atomic Energy Research Establishment (AERE), Savar, Dhaka, Bangladesh on human hair of corresponding tube well water users of these areas to determine the total accumulation of arsenic to their body. Hair samples collected from the region where the groundwater was found highly contaminated with arsenic. The obtained results of arsenic concentration in the lower age (Hb) categories of users (below 12 years of age users) is in the range of 0.33 to 3.29 /gmg/g (ppm) and that in the Hu categories (upper 12 years of age users) is 0.47 to 6.64 μg/g (ppm). Where as maximum permissible range is 1 ppm certified from WHO. Results show that the peoples are highly affected where the groundwater is highly contaminated with arsenic and acts as the primary source of arsenic poisoning among the peoples of those areas. The results indicate that human population is affected with arsenic locally using the contaminated water for a long time.     

Effect of trace metals on halophilic and mixed cultures in anaerobic treatment

Trace metals are known to stimulate the activity of anaerobic methanogenic bacteria involved in the degradation of organic matter. The objective of this research was to investigate the effect of three trace metals, iron, nickel and cobalt on the activity of halophilic methanogens, digester sludge and a mixed culture of halophilic bacteria and digester sludge, at various salt concentrations. Iron slightly stimulated both initial and maximum specific methanogenic activity (SMA) of halophilic methanogens at all salt concentrations. Iron addition was also able to increase both initial and maximum SMA of the mixed culture. Iron could not stimulate either initial or maximum SMA of digester sludge at salt concentrations of more than 10 g/L. Adding cobalt showed no benefit on the initial and maximum SMA of halophilic methanogens. A slight increase in the initial SMA was observed in mixed culture when cobalt was injected to the system containing sodium concentrations of 10–30 g/L. At salt concentrations above 40 g/L, cobalt could stimulate the maximum SMA of mixed culture. No benefits were found when cobalt was added to the digester sludge at sodium concentrations higher than 20 g/L. Nickel was observed to increase the initial SMA of digester sludge at all salt concentrations, and the maximum SMA of mixed culture at salt concentrations of 30–50 g/L.     

Application of X-ray computed tomography for analyzing cleat spacing and cleat aperture in coal samples

New techniques to determine distributions of cleat aperture, cleat orientation and cleat spacing from CT scans have been developed. For cleat orientation and spacing distributions, two different coal blocks were scanned. The CT scans have been analyzed for the three orthogonal directions. Histograms of the cleat orientations are bimodal, expressing the typical cleat texture of face and butt cleats and bedding perpendicular relaxation fractures. Deviations up to 20° from the peak values in the cleat orientation distributions were used as input for automated image analysis of cleat spacing. Distributions of the cleat spacing measurements are related to the face and butt cleat directions. The term “relevant cleat length” is introduced as a measure to extract the amount of cleat length involved with the cleat spacing measurements. The ratio ranges from 0.03 to 0.38 and expresses the difference in cleat texture in both samples. Cleat spacing versus relevant cleat length shows sample specific patterns for face cleat, butt cleat and bedding. To describe cleat aperture quantitatively, peak height and missing attenuation have been used. The image of a cleat was seen as a convolution of a rectangular fracture profile with a Gaussian point spread function.     

Uniaxial compression and tension tests of anthracite and loading rate dependence of peak strength

The mechanical characteristics of coal under uniaxial compressive stress and uniaxial tensile stress are key factors in investigations of the stability of galleries and coal faces, and are vital considerations for the efficient design of coalmines, disaster prevention, and environmental preservation. These mechanical characteristics have long been a topic of research, but remain insufficiently understood. In this study we performed uniaxial compression tests and uniaxial tension tests on coal, with particular attention to two concerns. The first was to measure the loading rate dependence of the peak strength of coal. Coal shows high sample-to-sample scatter in strength; test methods that are successful in comparatively homogeneous rock types cannot be used for coal. We therefore used an alternative test method that was recently developed by the authors. Anthracite samples were subjected to alternating slow and fast strain rates. Measured variations in stress during this process were used to estimate the loading rate dependence of peak strength. The second objective was to obtain complete stress–strain curves for coal under uniaxial tensile stress. It is difficult to hold samples secure during a tensile test; consequently, such curves have yet to be obtained. This study presents a successful application of the authors' method to the analysis of coal samples, yielding a complete stress–strain curve under tensile stress. The two methods presented here hold promise for application not only to anthracite but also to a wide variety of coals. It is possible to derive the values of the constants used in constitutive equations from the obtained experimental results. Once these equations are determined, they can be incorporated into finite-element software to investigate various time-dependent behaviors of coal and aid in the efficient design of coalmines and the prevention of subsidence and mine disasters.