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871.
Dietary intake of metals by Mumbai adult population 总被引:1,自引:0,他引:1
Raghunath R Tripathi RM Suseela B Bhalke S Shukla VK Puranik VD 《The Science of the total environment》2006,356(1-3):62-68
Daily intake of 12 metals (Na, K, Ca, Cu, Zn, Fe, Mn, Mg, Pb, Cd, Co and Ni) by Mumbai adult population were assessed by analysing duplicate diet samples. These metals were determined by flame atomic absorption spectrophotometry (AAS) and stripping voltammetric techniques. A total of 250 diet samples containing 170 vegetarian diet and 80 non-vegetarian diet collected during April 2003 to March 2004 were analysed during this study. Daily dietary intakes of 2.4 g Na and 1.2 g K were observed for Mumbai adults. Daily dietary intakes of Ca, Cu, Zn, Fe, Mn and Mg were 367, 1.0, 6.3, 6.7, 2.0 and 304 mg, respectively. Pb, Cd, Co and Ni intakes by Mumbai adults were 32.3, 2.2, 2.2 and 108 microg/day, respectively. From this study it has been observed that the intake of toxic metals such as Pb, Cd and Ni is much lower than the tolerable daily intake derived from PTWI given by FAO/WHO and could not be considered harmful in this group of subjects. Daily intake of the studied 12 metals was found to be higher in non-vegetarian diet compared to the vegetarian diet (P<0.02, 0.01). 相似文献
872.
G.Pandikumar D.Sunil Kumar M.M.Shanthi Bagchi Subhrojit A.John Arul D.Venkata Subramanian Rajeev Ranjan Prasad 《核技术(英文版)》2019,(8)
In fast reactors, the inherent neutron source strength is often insufficient for monitoring the reactor start-up operation with ex-core detectors. To increase the subcritical neutron flux, an auxiliary neutron source subassembly(SSA) is generally used to overcome this problem. In this study, the estimated neutron source strength and detector count rate of an antimony-beryllium-based SSA are obtained using the deterministic transport code DORT and Monte Carlo calculations. Because the antimony activation rate is a critical parameter, its sensitivity to the capture cross section and neutron flux spectrum is studied. The reaction cross section sensitivity is studied by considering data from different evaluated nuclear data files.It is observed that, because of the variation in the cross sections from different evaluated nuclear data files, the values of the saturation gamma( 1.67 MeV) activity and neutron strength predicted by ORIGEN2 lie within ±2%.The obtained antimony activation rate and sensitivity to the neutron flux are partially validated by irradiating samples of antimony in the KAMINI reactor. The average onegroup capture cross sections of bare and cadmium-covered ~(123)Sb samples obtained by the ratio method are 4.0 and 1.78 b, respectively. The results of the calculation predicting the activated neutron source strength as a function of operating time and sensitivity to the neutron spectrum in the irradiation region are also presented. 相似文献
873.
HgCdTe narrow-bandgap materials are used in the fabrication of infrared detectors and focal-plane arrays. Many of these advanced
devices require complex structures to be processed into them. Passivation of planar detectors is typically done with vacuum-evaporated
CdTe or related II–VI materials. New advanced detector topology necessitates the use of low-pressure chemical vapor deposition
(LPCVD) and atomic layer deposition (ALD) for improved conformal coverage. Preliminary studies on LPCVD of CdS and ALD of
CdTe were carried out and characterized for conformal coverage. The effects of CdS and CdTe films on HgCdTe minority-carrier
lifetime are also studied at 300 K and 77 K. 相似文献
874.
Peter Waboi Mwaurah Sunil Kumar Nitin Kumar Anil Panghal Arun Kumar Attkan Vijay Kumar Singh Mukesh Kumar Garg 《Comprehensive Reviews in Food Science and Food Safety》2020,19(5):2421-2446
Mango (Mangifera indica L.) is a fruit plant of family Anacardiaceae, widely grown all over the world, and is a very popular fruit in the world market. Mango fruit is the second most traded tropical fruit and fifth in terms of production globally. Large quantities of mango processing coproducts are generated (peels and seeds), which usually are discarded as waste, yet are a potential source of fat, protein, carbohydrate, and certain bioactive compounds. Mango kernel is a remarkably rich source of macronutrients and micronutrients including calcium, potassium, magnesium, phosphorus, and vitamins A, E, K, and C. Phytochemicals with a notable therapeutic potential such as tocopherols, phytosterols, carotenoids, polyphenols (gallotannins, flavonols, benzophenone derivatives, mangiferin, homomangiferin, isomangiferin, anthocyanins, kaempferol, and quercetin), and phenolic acids (4‐caffeoylquinic acids, caffeic, coumaric, ellagic, gallic, and ferulic acid) are reported. The phytochemicals have high antioxidant, antimicrobial, anticancer, and, antiproliferation activities and could be used for food, cosmetic, and pharmaceutical applications. The nutritional composition of mango kernel constitutes 32.34% to 76.81% carbohydrate, 6% to 15.2% fat, 6.36% to 10.02% protein, 0.26% to 4.69% crude fiber, and 1.46% to 3.71% ash on a dry weight basis. The nutritional profile of the kernel suggests its usability as a food ingredient in the development of value‐added products such as mango kernel oil, mango kernel butter, mango kernel flour, and biofilms among other diverse products. This comprehensive systematic review explores mango kernel as a potential and novel food ingredient to meet the needs of a health‐conscious population. The review also provides a remedy to waste management and environmental pollution. 相似文献
875.
Peter Waboi Mwaurah Sunil Kumar Nitin Kumar Arun Kumar Attkan Anil Panghal Vijay Kumar Singh Mukesh Kumar Garg 《Comprehensive Reviews in Food Science and Food Safety》2020,19(1):3-20
Conventional techniques of extracting oil using organic solvents pose health, safety, and environmental concerns. In modern extraction methods, green solvents such as water, ethanol, ethyl acetate, carbon dioxide, ionic liquids, and terpenes are currently gaining prominence. These green solvents present no signs of pollution and remain in liquid form over a temperature range of 0 to 140 °C. Other techniques covered in this review include microwave‐assisted enzymatic extraction, ultrasound‐assisted extraction, supercritical fluid technology, high pressure–assisted extraction, and pulse electric field–assisted extraction. These techniques are considered environmentally friendly because they exhibit less hazardous chemical synthesis, use renewable feedstock, and reduce the chemical load and emissions generated by organic solvents. Aqueous enzymatic extraction is a novel technique that uses enzymes as the medium for extraction of oil. Selection of the enzymes solely depends on the structure of the oilseed and the composition of the cell wall. Studies reveal an enzyme to substrate ratio of 1% to 8%, the temperature of 40 to 55 °C, and a pH of 4 to 8 to be typical for enzymatic extraction of oil from different oilseeds. Microwave‐assisted extraction has proven to impart significant effects on mass transfer and offers high throughput and extraction efficiency. A microwave power of 275 to 1,000 W and a temperature range of 30 to 60 °C are noticed in the different studies. The review presents a comprehensive account of the modern extraction techniques, the parameters responsible for yield and quality, and their industrial applications. Besides, the review highlights the optimized parameters for oil extraction from different oil‐bearing materials. 相似文献
876.
Weld cladding is a process for producing surfaces with good corrosion resistant properties by means of depositing/laying of
stainless steels on low-carbon steel components with an objective of achieving maximum economy and enhanced life. The aim
of the work presented here was to investigate the effect of auxiliary preheating of the solid filler wire in mechanized gas
metal arc welding (GMAW) process (by using a specially designed torch to preheat the filler wire independently, before its
emergence from the torch) on the quality of the as-welded single layer stainless steel overlays. External preheating of the
filler wire resulted in greater contribution of arc energy by resistive heating due to which significant drop in the main
welding current values and hence low dilution levels were observed. Metallurgical aspects of the as welded overlays such as
chemistry, ferrite content, and modes of solidification were studied to evaluate their suitability for service and it was
found that claddings obtained through the preheating arrangement, besides higher ferrite content, possessed higher content
of chromium, nickel, and molybdenum and lower content of carbon as compared to conventional GMAW claddings, thereby giving
overlays with superior mechanical and corrosion resistance properties. The findings of this study not only establish the technical
superiority of the new process, but also, owing to its productivity-enhanced features, justify its use for low-cost surfacing
applications. 相似文献
877.
Current–voltage (I–V) characteristics of diphenylthiocarbazone (DPh)-doped cellulose acetate grown from solution have been studied as a function of temperature, thickness and voltage in a metal–polymer–metal sandwich con-figuration. The role of the dopant molecular concentration in the polymer matrix and the modification of the conduction characteristics are studied. Initially, the conductivity increases as a function of dopant concentration, but at higher concentrations, it begins to decrease. The dopant molecules act as additional trapping centres at lower concentration, while at optimum concentration they provide a link between polymer molecules, leading to the formation of a charge transfer complex. The decrease in conductivity with higher concentration of doping is due to the onset of the increase in heterogeneity, which can increase the trapping sites for charge carriers. The variation of current for doped films with temperature shows different regions with different activation energies. This behaviour is explained in terms of the type of conduction mechanism operating in the material. At low voltages, Ohm’s law is followed, while at higher voltages space charge limited current is observed. It was also noted that a Richardson–Schottky emission is responsible to some extent for the transport of charge carriers. Quantitative information about the transport parameters is derived. ©1998 Society of Chemical Industry 相似文献
878.
Graft copolymerization of methacrylic acid onto isotactic polypropylene has been studied in water–methanol medium using γ-rays as the source of initiation. Graft copolymerization has been conducted by (1) mutual irradiation, (2) preirradiation, and (3) double irradiation methods. All of the reaction parameters that seem to influence grafting have been studied, and the optimum conditions leading to maximum percentage of grafting have been evaluated. A plausible mechanism for radiation-induced grafting of methacrylic acid onto polypropylene has been suggested, and the results have been explained on the basis of the proposed mechanism. A comparative study of graft copolymerization by different radiation methods has been made, and it was observed that the preirradiation method affords the best results. Evidence of grafting has been obtained from differential scanning calorimetric analysis and the dyeing behavior of the grafted material. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 143–152, 1998 相似文献
879.
Sunil Nair M. Nicklas J. L. Sarrao J. D. Thompson F. Steglich S. Wirth 《Journal of Superconductivity and Novel Magnetism》2009,22(2):195-199
We present an analysis of the normal-state magnetotransport in the heavy-fermion superconductor CeIrIn5. The Hall effect and the transverse magnetoresistance in this material do not appear to be uniquely correlated, as inferred
from the field dependence of the current ratio (R
σ
=σ
xy
/σ
xx
2
H). The Hall coefficient is seen to satisfy a scaling equation of the form R
H=f[H/(a+bT
c
)]. These results are compared to those observed earlier in CeCoIn5, and are discussed in terms of the contrasting phase diagram which the CeIrIn5 system exhibits in relation to its Co counterpart. 相似文献
880.
A novel class of organic‐inorganic polymer hybrids were developed by meltblending up to 50 (v/v) % [about 83 (w/w) %] tin‐based polyphosphate glass (Pglass) and low‐density polyethylene (LDPE) in conventional plastics processing equipment. The creep and recovery behavior of these polymer hybrids at 30°C were studied to understand the effect of the Pglass on the creep resistance of the LDPE. The results suggest that the Pglass acts as a reinforcement and an increase in the Pglass loading leads to significantly lower creep strains. This creep resistance is further enhanced by pretreating the Pglass with coupling agents prior to incorporating them into the Pglass‐LDPE hybrids. The experimental creep compliance of these materials conformed excellently with empirical power‐law equation and a modified Burger's model, suggesting that the materials are linearly viscoelastic under the test conditions. 相似文献