A convenient solid state metathetic synthesis has been developed for the preparation of metal tungstates MWO4 where M = Mn, Fe, Co, Ni and Zn using Na2WO4 and respective MCl2 as reactants. Stoichiometric quantities of respective reactants were mixed and ground for 2hrs. XRD patterns of the homogenised mixture heat treated at 400ºC for 4hrs and then washed free from NaCl bye product were in good agreement with the respective JCPDS data showing the formation of phase pure compounds in each case without any contamination. Microstructural investigation indicated particle size of the order of µm.
Benzimidazoles are known to represent a class of medicinally important compounds which are extensively used as antibacterial agents. Hence, a series of five 2-substituted benzimidazole precursors (1a-e) were synthesized via [4 + 1] condensation and imino compound (1f) by simple condensation in the presence of Conc. HCl as catalyst. Synthetic modification of N-1 position was achieved in order to obtain new 5-chloro-2,4-dinitrophenyl bearing 1,2-disubstituted benzimidazole 2a-e and 2f, and 3-chlorobenzyl bearing 1,2-disubstituted benzimidazole 3a-e and 3f in good to excellent yields using a facile approach. The chemical structures of all synthesized compounds were confirmed using spectroscopic means such as UV-visible, IR, Mass spectra, 1H and 13C NMR as well as C, H, N elemental analytical data.
Soils need to be tested before and after the establishments of plantations. This is because the results of a soil test gives a relative measure of the amount of nutrients available in the soil and thus are use as a base for nutrient diagnosis. The Calcium Acetate lactate (CAL) method for the extraction of available soil K and P and the CaCl2method for the extraction of available Mg were compared to the Acidic ammonium acetate- ethylene diaminetetraacetic acid (AAAc-EDTA) method for the determination of these elements in soil. A total of 130 samples were collected during a survey and analysed for K, P and Mg content after using the different extracting solutions. According to the results obtained, CAL and AAAc-EDTA methods were similar in their extracting power for P. In the case of K, the CAL method extracted only about half of the amount of K extracted using the AAAc-EDTA method. On the other hand, CaCl2 extracted about twice the amount of Mg extracted using the AAAc-EDTA method. These extraction methods were poorly correlated to each other except the methods for P. This shows that P data obtained by the two methods can be interpreted in the same way. The difference in the quantities of nutrients extracted was associated to the differences in the reaction mechanisms between the soil nutrients and the extracting solutions. There was an influence of pH and organic carbon content on the amount of K and Mg extracted. These preliminary studies indicate that the choice of the extraction procedure may depend on the resources available as well as the soil properties. However, the AAAc-EDTA extracting solution offers the advantage of extracting many nutrients and can save time and energy.
Aims: To correlate qualitatively and quantitatively biological effectiveness of irradiations of bio-test objects by neutrons, X- and gamma-rays within a wide range of doses, dose rates (dose powers), durations of action and spectral contents of the radiations.
Study Design: These irradiations were done with the help of well-known and newly elaborated sources of the above radiations based on isotopes, fission reactors, X-ray tubes and Dense Plasma Focus (DPF) devices.
Place and Duration of Study: Institute of Metallurgy and Material Science (IMET), Institute of Plasma Physics and Laser Microfusion (IPPLM), Moscow State University (MSU), and Medical Radiological Research Center (MRRC), between June 2007 and December 2011.
Methodology: As biological test objects of different contents and complexity we used enzymes of various types, serum, seminal fluid, human lymphocytes. Enzymes activity prior to and after irradiation was measured using spectrophotometer (Hitachi) within the wavelength range Δl = 300÷750 nm according to up-to-date techniques. In the comparative researches the cytogenetic action of fission neutrons (generated by nuclear reactors) and of fusion 14-MeV neutrons (from DPF) were studied with the most widespread test-system – chromosomal aberrations in human lymphocytes.
Results: The range of the variations of the coefficient of biological effectiveness for neutron radiation of dissimilar dose rates (dose powers) and neutron spectra as a rule does not go out from the limits of physiological oscillations at the neutron dose power that changes within 9 orders of magnitude (till the figure 108 Gy/min) and it coincides with the “classic” dose rate effect (a quadratic part of dose curves for cell survival or chromosomal aberrations). Yet in the field of radioenzymology the very powerful X-ray radiation results in activation or suppression of enzymes at doses differing by 4-5 orders of magnitude (to lesser doses) compared with analogous effects obtained with low power isotope and X-ray tube sources.
Conclusion: Resemblance of neutron action on dose powers within 9 orders of magnitude gives hope of applicability of the DPF neutron generators for the potential methods of neutron therapy instead of dangerous, expensive and cumbersome nuclear reactors. But the anomalously strong X-ray influence upon enzymes dictates careful application of super-high power X-ray pulses and demands further investigations of the nature of these effects.
Aims: The present paper aims to study the effect of aromatic structure on the inhibition of biogas production and more specifically the comparative study of benzyl and phenyl compounds chemical structure effects on the inhibition of methane production by digested pig manure methanogens. The objective of this study was also to examine the structure-toxicity relationships of aromatic compounds to acetoclastic methanogens.
Study Design: Anaerobic digestion of pig manure, anaerobic toxicity essay, comparison of benzyl and phenyl compounds structure effects on the inhibition of methane gas biosynthesis.
Place and Duration of Study: Department of Chemistry, University of Kinshasa (DR Congo), between September 2011 and May 2012.
Methodology: The toxicity to acetoclastic methanogenic bacteria was performed with the standard method of serum bottles; digested pig manure was utilized as inoculums and acetate as substrate. The methane gas volume produced was measured by serum bottles liquid displacement systems (Mariotte flask system).
Results: The obtained results indicate exist between the chemical structure of benzyl and phenyl compounds and their inhibitory effects on biosynthesis of methane by methanogenic bacteria. According to these results, α-chlorotoluene and bromobenzene with 0.61 and 2.90 mg/l IC50 values, respectively, are the most toxic compounds, while phenol and benzyl alcohol with IC50 values of 1248.90 and 2391.37 are less toxic.
Comparing the phenyl and benzyl compounds with the same substituents (Cl, Br, H, OH), their behavior was diverse. The benzyl chloride is more toxic than phenyl chloride and benzyl bromide is less toxic than phenyl bromide. Otherwise, benzyl alcohol is less toxic than phenol. A significant correlation between the toxicity of phenyl compounds and their hydrophobicity (R2 = 0.911). But any correlation was not found for benzyl compounds.
Conclusion: The obtained results indicate that relationships exist between the chemical structure of benzyl and phenyl compounds and their inhibitory effects on the production of methane by methanogenic archaea. The behavior of phenyl and benzyl are different in inhibition of methane production by the methanogens because their chemical structures are not identic.
The effect of fillers like red mud (RM) on dry sliding wear behavior of pure aluminium has been experimentally investigated. Pure aluminium of IE-07 grades from National Aluminium Company (NALCO), Angul of Odisha, India being collected with fillers in 10%, 15%, 20% and 30% based on weight were prepared using a stir casting technique. The dry sliding wear tests were conducted using pin-on-disc wear test machine. Tests were conducted for a sliding distance from 4.53×103m to 27.18×103m with wear track diameter 50mm-180mm. For each composition wear tests were conducted for different sliding speeds of 200 rpm (1.257m/s), 300 rpm (1.885m/s) and 400 rpm (3.141m/s) by applying normal loads of 10N, 20N and 30N. The wear rate and coefficient of friction were plotted against the normal load, sliding velocity and sliding distance for each filler composition. The results reveal that incorporation of red mud fillers leads to significant improvement in wear resistance of aluminium. The effect is the increase in interfacial area between aluminium matrix and red mud particles leading to the increase in strength appreciably.