Showing papers by "Aligarh Muslim University published in 2006"

ALICE: Physics Performance Report, Volume II

Abstract: ALICE is a general-purpose heavy-ion experiment designed to study the physics of strongly interacting matter and the quark–gluon plasma in nucleus–nucleus collisions at the LHC. It currently involves more than 900 physicists and senior engineers, from both the nuclear and high-energy physics sectors, from over 90 institutions in about 30 countries.The ALICE detector is designed to cope with the highest particle multiplicities above those anticipated for Pb–Pb collisions (dNch/dy up to 8000) and it will be operational at the start-up of the LHC. In addition to heavy systems, the ALICE Collaboration will study collisions of lower-mass ions, which are a means of varying the energy density, and protons (both pp and pA), which primarily provide reference data for the nucleus–nucleus collisions. In addition, the pp data will allow for a number of genuine pp physics studies.The detailed design of the different detector systems has been laid down in a number of Technical Design Reports issued between mid-1998 and the end of 2004. The experiment is currently under construction and will be ready for data taking with both proton and heavy-ion beams at the start-up of the LHC.Since the comprehensive information on detector and physics performance was last published in the ALICE Technical Proposal in 1996, the detector, as well as simulation, reconstruction and analysis software have undergone significant development. The Physics Performance Report (PPR) provides an updated and comprehensive summary of the performance of the various ALICE subsystems, including updates to the Technical Design Reports, as appropriate.The PPR is divided into two volumes. Volume I, published in 2004 (CERN/LHCC 2003-049, ALICE Collaboration 2004 J. Phys. G: Nucl. Part. Phys. 30 1517–1763), contains in four chapters a short theoretical overview and an extensive reference list concerning the physics topics of interest to ALICE, the experimental conditions at the LHC, a short summary and update of the subsystem designs, and a description of the offline framework and Monte Carlo event generators.The present volume, Volume II, contains the majority of the information relevant to the physics performance in proton–proton, proton–nucleus, and nucleus–nucleus collisions. Following an introductory overview, Chapter 5 describes the combined detector performance and the event reconstruction procedures, based on detailed simulations of the individual subsystems. Chapter 6 describes the analysis and physics reach for a representative sample of physics observables, from global event characteristics to hard processes.

Potential Applications of the Oxidoreductive Enzymes in the Decolorization and Detoxification of Textile and Other Synthetic Dyes from Polluted Water: A Review

Abstract: Recently, the enzymatic approach has attracted much interest in the decolorization/degradation of textile and other industrially important dyes from wastewater as an alternative strategy to conventional chemical, physical and biological treatments, which pose serious limitations. Enzymatic treatment is very useful due to the action of enzymes on pollutants even when they are present in very dilute solutions and recalcitrant to the action of various microbes participating in the degradation of dyes. The potential of the enzymes (peroxidases, manganese peroxidases, lignin peroxidases, laccases, microperoxidase-11, polyphenol oxidases, and azoreductases) has been exploited in the decolorization and degradation of dyes. Some of the recalcitrant dyes were not degraded/decolorized in the presence of such enzymes. The addition of certain redox mediators enhanced the range of substrates and efficiency of degradation of the recalcitrant compounds. Several redox mediators have been reported in the literature, but very few of them are frequently used (e.g., 1-hydroxybenzotriazole, veratryl alcohol, violuric acid, 2-methoxy-phenothiazone). Soluble enzymes cannot be exploited at the large scale due to limitations such as stability and reusability. Therefore, the use of immobilized enzymes has significant advantages over soluble enzymes. In the near future, technology based on the enzymatic treatment of dyes present in the industrial effluents/wastewater will play a vital role. Treatment of wastewater on a large scale will also be possible by using reactors containing immobilized enzymes.

Antidiabetic and antioxidant activity of Annona squamosa extract in streptozotocin-induced diabetic rats.

Abstract: Introduction The aim of the study is to analyse the antioxidant effect of oral administration of aqueous extract of Annona squamosa (A. squamosa) leaf on blood glucose, haemoglobin, glycosylated haemoglobin, plasma insulin, antioxidant enzymes and lipid peroxidation in liver and kidney to streptozotocin (STZ)-induced diabetic rats. Methods Aqueous extract of A. squamosa on blood glucose, haemoglobin, glycosylated haemoglobin, plasma insulin, serum lipid and the levels of lipid peroxides and antioxidant enzymes, such as catalase, superoxide dismutase, glutathione peroxidase and reduced glutathione, were examined in the liver and kidney tissues of control and experimental groups. Results Oral administration of A. squamosa aqueous extract to diabetic rats for 30 days significantly reduced the levels of blood glucose, lipids and lipid peroxidation, but increased the activities of plasma insulin and antioxidant enzymes, like catalase, superoxide dismutase, reduced glutathione and glutathione peroxidase. Conclusion The A. squamosa aqueous extract supplementation is useful in controlling the blood glucose level, improves the plasma insulin, lipid metabolism and is beneficial in preventing diabetic complications from lipid peroxidation and antioxidant systems in experimental diabetic rats; therefore, it could be useful for prevention or early treatment of diabetes mellitus.

Biochemical effects of Nigella sativa L seeds in diabetic rats.

Abstract: Oral administration of ethanol extract of N. sativa seeds (300 mg/kg body weight/day) to streptozotocin induced diabetic rats for 30 days significantly reduced the elevated levels of blood glucose, lipids, plasma insulin and improved altered levels of lipid peroxidation products (TBARS and hydroperoxides) and antioxidant enzymes like catalase, superoxide dismutase, reduced glutathione and glutathione peroxidase in liver and kidney. The results confirm the antidiabetic activity of N. sativa seeds extract and suggest that because of its antioxidant effects its administration may be useful in controlling the diabetic complications in experimental diabetic rats.

The importance of impurity analysis in pharmaceutical products: an integrated approach

Abstract: To purify a material and remove the excess impurities one should first recognize that whether they are actually present and what their nature is. In the past, this was not always done. But presently drug analysis and pharmaceutical impurities are the subjects of constant review in the public interest. The International Conference on Harmonisation (ICH) guidelines achieved a great deal in harmonizing the definitions of the impurities in new drug substances. It is necessary to perform all the investigations on appropriate reference standards of drug and impurities to get meaningful specifications. In order to meet the challenges to ensure high degree of purity of drug substances and drug products, a scheme is proposed for profiling drug impurity. Finally, analytical methods based on analytical instrumentation must be employed to quantitate drug substance and its impurities. Important aspects and suggestions related to drug analysis and pharmaceutical impurities are discussed.

On the Euler sequence spaces which include the spaces ℓp and ℓ∞ II

Abstract: By e p r , we mean the space of all sequences whose Euler transforms of order r are in the sequence spaces l p and l ∞ (see [B. Altay, F. Basar, M. Mursaleen, On the Euler sequence spaces which include the spaces l p and l ∞ I, Inform. Sci. (2005) (in press)]), where 1 ≤ p ∞ . In the present paper, we essentially characterize the classes ( e p r : l ∞ ) , ( e 1 r : l p ) and ( e p r : f ) of infinite matrices for 1 p ≤ ∞ and give the characterizations of some other matrix mappings from the space e p r to the Euler, Riesz, difference, etc., sequence spaces, by means of a given basic lemma. We devote the final section of the paper to examining some geometric properties of the space e p r .

Evaluation of anti-methicillin-resistant Staphylococcus aureus (MRSA) activity and synergy of some bioactive plant extracts.

Abstract: Anti-methicillin-resistant Staphylococcus aureus (MRSA) activity of ethanolic extracts of four medicinal plants namely Acorus calamus (rhizome) Hemidesmus indicus (stem), Holarrhena antidysenterica (bark), and Plumbago zeylanica (root), were detected with inhibition zone size ranged from 11 to 44 mm and minimum inhibitory concentration (MIC) varied from 0.32 to 3.25 mg/mL. Further, ethyl acetate, acetone and methanol fractions of above plants demonstrated antibacterial activity. The potency of these fractions based on zone of inhibition and MIC value was relatively higher in P. zeylanica (ethylacetate fraction), followed by acetone fractions of H. indicus, A. calamus, and H. antidysenterica. Time kill assay with most promising fractions of these plant extracts, demonstrated concentration-dependent killing of MRSA within 9-12 h of incubation. Interestingly, synergistic interaction among alcoholic extracts and some fractions of above four plants was evident against MRSA. Further, synergistic interaction of these extracts was detected with one or more antibiotics tested (tetracycline, chloramphenicol, ciprofloxacin, cefuroxime and ceftidizime). The findings also validate the traditional uses of above plants against infectious diseases. Phytochemical studies demonstrated flavonoids and phenols as major active constituents. Further investigations are needed to characterize the active principle and its interaction mechanism with antibiotics.

Micellization of monomeric and dimeric (gemini) surfactants in polar nonaqueous-water-mixed solvents

Abstract: Dimeric or gemini surfactants are novel surfactants that are finding a great deal of discussion in the academic and industrial arena. They consist of two hydrophobic chains and two polar head groups covalently linked by a spacer. Data on critical micelle concentration (cmc) and degree of counterion dissociation (α) are reported on bis-cationic C16H33N+(CH3)2–(CH2)s–N+(CH3)2C16H33, 2Br−, referred to as 16-s-16, for spacer lengths s=4, 5, 6 in aqueous and in polar nonaqueous (1-propanol, 2-methoxyethanol or methyl cellosolve, dimethyl sulfoxide, acetonitrile)-water-mixed solvents. The behavior is compared with conventional monomeric surfactant cetyltrimethylammonium bromide (CTAB). Thermodynamic parameters are obtained from the temperature dependence of the cmc values. It is observed that micellization tendency of the surfactants decreases in the presence of polar nonaqueous solvents. However, detailed studies with dimethylsulfoxide (DMSO) show that the geminis nearly outclass the micellization-arresting property of this solvent. Also, within geminis, higher spacer length is found suitable for showing micellization even with high DMSO content (50% v/v). The implications of these results of gemini micellization may be useful in micellar catalysis in polar nonaqueous solvents.

Dietary branched-chain amino acid valine, isoleucine and leucine requirements of fingerling Indian major carp, Cirrhinus mrigala (Hamilton).

Abstract: Three 8-week growth experiments were conducted to quantify the requirements of the fingerling Cirrhinus mrigala for the dietary branched-chain amino acids valine (experiment 1), isoleucine (experiment 2) and leucine (experiment 3). Six isonitrogenous (400 g/kg) and isoenergetic (17.90 kJ/g) test diets were formulated with a gradation of 2.5 g/kg for each test amino acid, valine (7.5-20 g/kg), isoleucine (5.0-17.5 g/kg) and leucine (7.5-20 g/kg), and fed to randomly stocked fish in circular troughs. In experiment 1, the maximum weight gain (312 %), best feed conversion ratio (FCR; 1.45) and best protein efficiency ratio (PER; 1.72) were obtained in fish fed 15.0 g dietary valine/kg. In experiment 2, the highest weight gain (317 %), best FCR (1.47) and best PER (1.70) were recorded at 12.5 g dietary isoleucine/kg, and in experiment 3, the highest weight gain (308 %), best FCR (1.46) and best PER (1.71) were noted at 15.0 g dietary leucine/kg. A quadratic regression analysis of weight gain, FCR and PER data showed an optimum requirement at 15.9, 15.0 and 14.8 g/kg for valine, 13.2, 12.3 and 12.1 g/kg for isoleucine and 15.6, 15.4 and 15.1 g/kg for leucine in dry diets. Low body moisture and higher protein were noted in fish fed diets containing 15.5, 12.5 and 15.0 g valine, isoleucine and leucine per kg, respectively. Body fat increased with increasing levels of the branched-chain amino acids. On the basis of a regression analysis of growth data, it is recommended that a diet for C. mrigala should contain valine at 15.2, isoleucine at 12.6 and leucine at 15.4 g/kg dry diet, corresponding to 38.0, 31.5 and 38.5 g/kg dietary protein, respectively.

DNA damage and mutagenicity induced by endosulfan and its metabolites.

Abstract: Endosulfan is a widely used broad-spectrum organochlorine pesticide, which acts as a contact and stomach poison. Nontarget species, such as cattle, fish, birds, and even humans, are also affected. Studies on the genotoxicity and mutagenicity of endosulfan have been inconsistent and nothing is known about the genotoxicity of its metabolites. In the present study, endosulfan (as a commercial isomeric mixture and as the alpha- and beta-isomers), and metabolites of endosulfan (the sulfate, lactone, ether, hydroxyether, and diol derivatives) were assayed for their ability to induce DNA damage in Chinese hamster ovary (CHO) cells and human lymphocytes using the Comet assay and were assayed for their mutagenicity using the Salmonella reversion assay (Ames test with TA98, TA97a, TA102, TA104, and TA100, with and without S9 activation). The compounds produced statistically significant (P < 0.01), concentration-dependent (0.25-10 microM) increases in DNA damage in both CHO cells and human lymphocytes. Endosulfan lactone caused the most DNA damage in CHO cells, while the isomeric mixture of endosulfan produced the greatest response in lymphocytes. The test compounds also were mutagenic in Salmonella strains at concentrations of 1-20 mug/plate (P < 0.05), with TA98 being the most sensitive strain and the diol and hydroxyether metabolites producing the highest responses. The results indicate that exposure to sublethal doses of endosulfan and its metabolites induces DNA damage and mutation. The contribution of the metabolites to the genotoxicity of the parent compound in Salmonella and mammalian cells, however, is unclear, and the pathways leading to bacterial mutation and mammalian cell DNA damage appear to differ.

Biosorption of Ni, Cr and Cd by metal tolerant Aspergillus niger and Penicillium sp. using single and multi-metal solution

Abstract: Fungi including Aspergillus and Penicillium, resistant to Ni2+, Cd2+, and Cr6+ were isolated from soil receiving long-term application of municipal wastewater mix with untreated industrial effluents of Aligarh, India. Metal tolerance in term of minimum inhibitory concentration (MIC) was 125-550 microg/ml for Cd, 300-850 microg/ml for Ni and 300-600 microg/ml for Cr against test fungi. Two isolates, Aspergillus niger and Penicillium sp. were tested for their Cr, Ni and Cd biosorption potential using alkali treated, dried and powdered mycelium. Biosorption experiment was conducted in 100 ml of solution at three initial metal concentrations i.e., 2, 4 and 6 mM with contact time (18 hr) and pretreated fungal biomass (0.1g) at 25 degrees C. Biosorption of all metals was found higher at 4 mM initial metal concentration as compared to biosorption at 2 and 6 mM concentrations. At 4 mM initial metal concentration, chromium biosorption was 18.05 and 19.3 mg/g of Aspergillus and Penicillium biomasses, respectively. Similarly, biosorption of Cd and Ni ions was also maximum at 4 mM initial metal concentration by Aspergillus (19.4 mg/g for Cd and 25.05 mg/g of biomass for Ni) and Penicillium (18.6 mg/g for Cd and 17.9 mg/g of biomass for Ni). In general, biosorption of metal was influenced by initial metal concentration and type of the test fungi. The results indicated that fungi of metal contaminated soil have high level of metal tolerance and biosorption properties.

Applications of Hg(II) sensitive polyaniline Sn(IV) phosphate composite cation-exchange material in determination of Hg2+ from aqueous solutions and in making ion-selective membrane electrode

Abstract: Polyaniline Sn(IV) phosphate an ‘organic–inorganic’ composite material, was prepared via sol–gel mixing of organic polymer polyaniline into the matrices of the inorganic precipitate of Sn(IV) phosphate The ion-exchange capacity and distribution coefficients with respect to various metal ions were determined on the column of polyaniline Sn(IV) phosphate The distribution studies showed the selectivity of Hg(II) ions by this material However, the sensitivity level of Hg(II) ions on the composite material was determined quantitatively Hg(II) ions were separated and determined from the binary aqueous mixtures of Hg(II)–Cu(II), Hg(II)–Ni(II), Hg(II)–Cd(II), Hg(II)–Co(II), Hg(II)–Al(III), etc For the determination of Hg(II) ions in aqueous solutions, a Hg(II) ion sensitive membrane electrode was prepared by means of this composite cation-exchanger as the electroactive material The membrane electrode was mechanically stable with quick response time and could be operated over a wide pH range with a slope of 30 mV per decade change in a linear concentration range of 1 × 10−1 to 1 × 10−6 M The selectivity coefficients were determined by the mixed solution method and revealed that the electrode was selective for Hg(II) in the presence of interfering cations The practical utility of this electrode was established by employing it as an indicator electrode in the potentiometric titration of Hg(II)

In vitro rapid regeneration of plantlets from nodal explants of Mucuna pruriens : a valuable medicinal plant

Abstract: A rapid and efficient protocol for the large-scale propagation of a potential medicinal plant, Mucuna pruriens, through in vitro culture of nodal segment explants obtained from 15-day-old aseptic seedlings is described. Of the three different cytokinins, 6-benzyladenine (BA), kinetin (Kin) and 2-isopentenyl adenine (2-iP) evaluated as supplements to Murashige and Skoog (MS) medium, BA at an optimal concentration of 5.0 μM was effective in inducing multiple shoots. Strength of the basal media also influenced the efficiency of shoot regeneration. The frequency of shoot regeneration tended to increase when the salt concentration in the basal media was reduced. Highest number of multiple shoots (23.3) and maximum average length (5.6 cm) were standardised on half-strength MS medium supplemented with 5.0 μM BA along with 0.5 μM α-naphthalene acetic acid (NAA) at pH 5.8. Rooting was best induced in shoots excised from proliferated shoot cultures on MS medium augmented with an optimal concentration of 1.0 μM indole-3-butyric acid (IBA). The in vitro-raised plantlets with well-developed shoots and roots were successfully established in earthen pots containing garden soil and were grown in greenhouse with 90% survival rate. The results of this study provide the first report on in vitro plant regeneration of M. pruriens.

Mammary tuberculosis: analysis of thirty-eight patients.

Abstract: Thirty-eight patients with mammary gland tuberculosis were evaluated over a 5-year period presenting to the surgical unit of our institution. Unilateral involvement of the breast in a woman presenting at an average age of 29 years was the commonest observation. A lump in the breast with or without discharging sinuses was the most common clinical presentation. Ten (26%) of these patients had breast pain with or without increased breast nodularity. Axillary lymph nodal involvement was evident in 14 (36%) of our patients. Only five patients had associated pulmonary tuberculosis, the rest having an isolated involvement of the breast. Fine-needle aspiration cytology was the most reliable diagnostic modality. Medical therapy with antitubercular drugs ranging from 6 to 9 months was the mainstay of treatment. Surgical intervention was reserved for selected refractory cases.

Semiconductor-mediated Photocatalyzed degradation of a herbicide derivative, chlorotoluron, in aqueous suspensions.

Abstract: The photocatalytic degradation of a herbicide derivative, chlorotoluron [3-(3-chloro-4-methylphenyl)-1,1-dimethylurea, 1], has been investigated in aqueous suspensions of titanium dioxide (TiO2) un...

Preparation, physico-chemical characterization, analytical applications and electrical conductivity measurement studies of an ‘organic–inorganic’ composite cation-exchanger: Polyaniline Sn(IV) phosphate

Abstract: Polyaniline Sn(IV) phosphate, an ‘organic–inorganic’ composite material, was synthesized via sol–gel mixing of an electrically conducting organic polymer polyaniline into the matrices of inorganic precipitate of Sn(IV) phosphate. This material was used as a cation-exchanger. The physico-chemical properties of the material were determined using AAS, CHN elemental analysis, ICP-MS, UV–VIS spectrophotometry, FTIR, TGA–DTA, XRD, and SEM studies. Ion-exchange capacity, chemical stability, thermal stability and distribution behavior were also carried out to understand the cation-exchange behavior of the material. On the basis of distribution studies, the material was found to be highly selective for Pb(II). Its selectivity was examined by achieving some important binary separations like Pb(II)–Mg(II), Pb(II)–Sr(II), Pb(II)–Zn(II), and Pb(II)–Fe(III) on its column. This material possessed DC electrical conductivity in the semi-conducting range, i . e . 10 −5 –10 −3 S cm −1 . The stability in terms of DC electrical conductivity retention was also studied in an oxidative environment by two slightly different techniques viz . isothermal and cyclic techniques. The DC electrical conductivity of composite material was found stable upto 110 °C under ambient conditions.

Molecular epidemiology of clinical and carrier strains of methicillin resistant Staphylococcus aureus (MRSA) in the hospital settings of north India

Abstract: The study was conducted between 2000 and 2003 on 750 human subjects, yielding 850 strains of staphylococci from clinical specimens (575), nasal cultures of hospitalized patients (100) and eye & nasal sources of hospital workers (50 & 125 respectively) in order to determine their epidemiology, acquisition and dissemination of resistance genes. Organisms from clinical samples were isolated, cultured and identified as per the standard routine procedures. Susceptibility was measured by the agar diffusion method, as recommended by the Nat ional Committee for Clinical Laboratory Standards (NCCLS). The modified method of Birnboin and Takahashi was used for isolation of plasmids from staphylococci. Pulsed-field gel electrophoresis (PFGE) typing of clinical and carrier Methicillin resistant Staphylococcus aureus (MRSA) strains isolated during our study was performed as described previously. It was shown that 35.1% of Staphylococcus aureus and 22.5% of coagulase-negative staphylococcal isolates were resistant to methicillin. Highest percentage of MRSA (35.5%) was found in pus specimens (n = 151). The multiple drug resistance of all MRSA (n = 180) and Methicillin resistant Coagulase-negative Staphylococcus aureus (MRCNS) (n = 76) isolates was detected. In case of both methicillin-resistant as well as methicillin-sensitive Saphylococcal isolates zero resistance was found to vancomycin where as highest resistance was found to penicillin G followed by ampicillin. It was shown that the major reservoir of methicillin resistant staphylococci in hospitals are colonized/infected inpatients and colonized hospital workers, with carriers at risk for developing endogenous infection or transmitting infection to health care workers and patients. The results were confirmed by molecular typing using PFGE by Sma I-digestion. It was shown that the resistant markers G and T got transferred from clinical S. aureus (JS-105) to carrier S. aureus (JN-49) and the ciprofloxacin (Cf) and erythromycin (E) resistance seemed to be chromosomal mediated. In one of the experiments, plasmid pJMR1O from Staphylococcus aureus coding for ampicillin (A), gentamicin (G) and amikacin (Ak) resistance was transformed into Escherichia coli. The minimal inhibitory concentrations (MICs) for A and G were lower in E. coli than in S. aureus. However, the MIC for Ak was higher in E. coli transformants than in S. aureus. There is a progressive increase in MRSA prevalence and multi-drug resistance in staphylococci. Vancomycin is still the drug of choice for MRSA infections. The major reservoir of methicillin resistant staphylococci in hospitals is colonized/infected inpatients and colonized hospital workers. Resistance transfer from staphylococci to E. coli as well as from clinical to carrier staphylococci due to antibiotic stress seemed to be an alarming threat to antimicrobial chemotherapy.

Dynamic light scattering studies of additive effects on the microstructure of aqueous gemini micelles

Abstract: Dynamic light scattering (DLS) measurements have been performed at 30 °C to see the effects of additives on the microstructure of gemini alkanediyl-α,ω-bis(dimethylcetylammonium bromide) surfactants, (Br-, n-C16H33N+Me2−(CH2)s−Me2− N+n-C16H33, Br-, 16−s−16, where s = 4, 5, 6). In pure aqueous solutions, the hydrodynamic diameter, Dh, was found to increase rapidly with geminis in comparison to their monomeric counterpart cetyltrimethylammonium bromide (n-C16H33N+Me3, Br-, CTAB) on increasing surfactant concentration. The additives considered in the present study are n-alcohols (C4-C6OH) and n-hexylamine (C6NH2) on the micellar growth of 0.03 M 16−4−16 in the presence and absence of 0.001 M KBr. The presence of 0.001 M KBr or organic additives at lower concentrations singly or jointly has little effect on the micellar size. As the chain length of the additive increases, the size increases with the increase of additive concentration, the magnitude being substantial in the presence of 0.001 M KBr. However, fo...

Template synthesis of symmetrical transition metal dithiocarbamates

Abstract: Novel transition metal dithiocarbamates of the type [M2(etdtc)2] and [M1(etdtc)Cl]2 where M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II), M1 = Cr(III), Fe(III) and etdtc = (S4N4C11H18 ) have been synthesized by the use of self-assembly techniques. The metal dithiocarbamates were prepared from the primary amine, CS2 and metal chloride. They have been characterized by spectroscopic, TGA/DSC, magnetic susceptibility and conductivity data. The complexes, [Mn2(etdtc)2], [Fe2(etdtc)2], [Co2(etdtc)2], [Zn2(etdtc)2], [Cd2(etdtc)2] and [Hg2(etdtc)2] have been suggested to be tetrahedral while [Ni2(etdtc)2] and [Cu2(etdtc)2] have square-planar geometry. [Cr(etdtc)Cl]2 and [Fe(etdtc)Cl]2 have chlorine bridged distorted-octahedral geometry. It has been observed that the dithiocarbamato moiety is symmetrically bonded in all the cases. A three stage TGA profile is observed for all the complexes leading to the formation of respective metal sulfide as the end-product. The molar conductance of 10-3 mol L-1 solution of the complexes measured in DMSO is indicative of their non-ionic nature.

Matlab/Simulink Model of Space Vector PWM for Three-Phase Voltage Source Inverter

Abstract: Variable voltage and frequency supply to AC drives is invariably obtained from a three-phase voltage source inverter (VSI). A number of pulse width modulation (PWM) schemes are used to obtain variable voltage and frequency supply. The most widely used PWM schemes for three-phase VSI are carrier-based sinusoidal PWM and space vector PWM (SVPWM). There is an increasing trend of using space vector PWM (SVPWM) because of their easier digital realisation and better dc bus utilisation. This paper focuses on step by step development of MATLAB/SIMULINK model of SVPWM. Firstly model of a three-phase VSI is discussed based on space vector representation. Next simulation model of SVPWM is obtained using MATLAB/SIMULINK. Simulation results are also provided.