An electron paramagnetic resonance study of Pr_{0.6}Ca_{0.4}MnO_{3} across the charge ordering transition

We report the first electron paramagnetic resonance studies of single crystals and powders of Pr_{0.6}Ca_{0.4}MnO_{3} in the 300-4.2 K range, covering the charge ordering transition at ~ 240 K and antiferromagnetic transition (T_N) at ~ 170 K. The asymmetry parameter for the Dysonian single crystal spectra shows anomalous increase at T_{co}. Below T_{co} the g-value increases continuously, suggesting a gradual strengthening of orbital ordering. The linewidth undergoes a sudden increase at T_{co} and continues to increase down to T_N. The intensity increases as the temperature is decreased till T_{co} due to the renormalization of magnetic susceptibility arising from the build up of ferromagnetic correlations. The value of the exchange constant, J, is estimated to be 154 K.Comment: Uses Revtex3.

Amorphous carbon film deposition on inner surface of tubes using atmospheric pressure pulsed filamentary plasma source

Uniform amorphous carbon film is deposited on the inner surface of quartz tube having the inner diameter of 6 mm and the outer diameter of 8 mm. A pulsed filamentary plasma source is used for the deposition. Long plasma filaments (~ 140 mm) as a positive discharge are generated inside the tube in argon with methane admixture. FTIR-ATR, XRD, SEM, LSM and XPS analyses give the conclusion that deposited film is amorphous composed of non-hydrogenated sp2 carbon and hydrogenated sp3 carbon. Plasma is characterized using optical emission spectroscopy, voltage-current measurement, microphotography and numerical simulation. On the basis of observed plasma parameters, the kinetics of the film deposition process is discussed

Relations between structural distortions and transport properties in Nd0.5_{0.5}Ca0.5_{0.5}MnO3_3 strained thin films

Strained thin films of charge/orbital ordered (CO/OO) $Nd_{0.5}Ca_{0.5}MnO_3$ (NCMO) with various thickness have grown on (100)-SrTiO$_3$ and (100)-LaAlO$_3$ substrates, by using the Pulsed Laser Deposition (PLD) technique. The thickness of the films influences drastically the transport properties. As the thickness decreases, the CO transition increases while at the same time the insulator-to-metal transition temperature decreases under application of a 7T magnetic field. Clear relationships between the structural distortions and the transport properties are established. They are explained on the basis of the elongation and the compression of the Mn-O-Mn and Mn-O bond angles and distances of the \QTR{it}{Pnma} structure, which modify the bandwidth and the Jahn-Teller distortion in these materialsComment: 11 pages, 6 figures. to be published in Journal Physics: Condensed Matte

Cooling rate dependence of the antiferromagnetic domain structure of a single crystalline charge ordered manganite

The low temperature phase of single crystals of Nd$_{0.5}$Ca$_{0.5}$MnO$_3$ and Gd$_{0.5}$Ca$_{0.5}$MnO$_3$ manganites is investigated by squid magnetometry. Nd$_{0.5}$Ca$_{0.5}$MnO$_3$ undergoes a charge-ordering transition at $T_{CO}$=245K, and a long range CE-type antiferromagnetic state is established at $T_N$=145K. The dc-magnetization shows a cooling rate dependence below $T_N$, associated with a weak spontaneous moment. The associated excess magnetization is related to uncompensated spins in the CE-type antiferromagnetic structure, and to the presence in this state of fully orbital ordered regions separated by orbital domain walls. The observed cooling rate dependence is interpreted to be a consequence of the rearrangement of the orbital domain state induced by the large structural changes occurring upon cooling.Comment: REVTeX4; 7 pages, 4 figures. Revised 2001/12/0

Preclinical Safety Evaluation of Rasa Karpoora Kuligai

The test drug Rasa Karpoora Kuligai is selected from the text, Gunapadam Thathu Jeevam for the evaluation of safety, efficacy and therapeutic potency. Aim of the dissertation is to study the toxicity of the test drug Rasa Karpoora Kuligai by universal accepted scientific methods. The review of the literatures and scientific research reveals pepper, garlic, betel leaf, mother milk that, are having anti cancer, anti-oxidant, anti-inflammatory activities. The test drug was prepared properly by the given procedure all the ingredients were identified and authenticated by the concerned departments. The preparation of trial drug was standardized primarily by physicochemical and biochemical analysis The physicochemical analysis the drug shows brown in colour with pleasant odour and bitter mixed light pungent in taste. In physiochemical analysis the total Ash value of test drug is 6.87 which shows the total inorganic content (ammonium, potassium, calcium, chloride, iron) present in the drug. These contents are having important role in physiological functions of the body. Biochemical analysis shows the presence of calcium, sulphate, chloride, starch, phosphate, ferrous iron these compounds are protect the body from the risk of cancer. In instrumental analysis the ICP-OES result shows the toxic heavy metals such as As, Hg, Cd, Pb, Al, Cu, Ni are in Below Detection Limit(BDL) . The main ingredient of the drug is mercuric II chloride, but the final product RKK shows below detection limit of the mercury. SEM analysis of the Rasa karpoora kuligai shows that the uniform distribution of particles presents in the entire field. Most of the particles present in the sample is nano size and near nano size, average particle size is 4.64µm - 7.51µm which increase the efficacy and bio availability of the test drug. The acute toxicity study shows that Rasa Karpoora Kuligai did not produce any toxic effect at dose of 300mg/kg, and 2000 mg/kg to rats. So No-Observed- Adverse-Effect-Level (NOAEL) of Rasa karpoora kuligai is above 2000mg/kg.Bw. In sub acute toxicity study test drug Rasa Karpoora Kuligai can be considered safe, as it did not cause either any lethality or adverse changes with general behaviour of rats and also there were no observable detrimental effects (230, 450 & 600 mg/kg body weight) over a period of 28 days. These results have demonstrated that the Rasa Karpoora Kuligai is relatively safe when administered orally in rats. In organs of control group and drug treated groups no abnormality was detected. Histopathological examination revealed normal architecture in comparison with control and treated animal. CONCLUSION: From the results of analytical evaluation of the test drug Rasa Karpoora Kuligai, it is inferred that quality and stability was good when prepared under the standard protocol mentioned in this study. Qualitative analysis of RKK reveals the purity and bioavailability of the drug. As heavy metals were found to be with in the permissible limit so the drug is safe for oral consumption. The particle size of the test drug was determined by SEM analysis. In vivo toxicity study reveals the drug RKK shows no mortality and signs of toxicity upto 2000 mg/Kg bodyweight in acute oral administration. In 28 days repeated oral toxicity study there was significantly changes in haematological, biochemical parameter in RKK (230mg, 450mg & 600mg /Kg bodyweight) treated group but the levels were with in physiological limits. The histopathology report also confirms that there are no remarkable cellular changes at all the dose level. Based on the results, it can be concluded that, the dose level of Rasa Karpoora Kuligai is sundai alavu (0.798mg) mentioned in Gunapadam Thathu Jeevam is a safe dosage for human consumption

EXPERIMENTAL INVESTIGATION AND NEURAL NETWORK PREDICTION OF THE PERFORMANCE OF A MIXED MODE SOLAR DRYER FOR COCONUT

The shelf life of agricultural food products may be enhanced by reducing their moisture contents, by means of a drying process. The present work aims at drying coconut yielding copra. This paper presents the design, analysis of a mixed mode solar dryer for food preservation and energy saving. In the mixed mode solar dryer, the drying cabinet absorbs solar energy directly through the transparent roof and during the same time the heated air from a solar collector is passed through a tray. Various measurements like solar radiation, mass flow rate, and moisture content and relative humidity have been observed. From previous literature four different models (Newton, Page, Henderson & Pabis and Wang & Singh) are chosen for testing the performance of mixed mode solar dryer. Selected models are evaluated by using EMD, ERMS, R2 and ðœ’2 and it is concluded that page model is more suitable for the fabricated cabinet solar dryer at air flow rate 0.009Kg/s based on the experimental analysis. The direct radiant solar energy and a convective hot air stream dry the products, resulting in longer life for the products which are also free from impurities. The experimental results are utilized to evolve a suitable mathematical model, among the different models that are chosen, for copra. This will help in designing suitable dryers for actual users. Also, a multilayer neural network approach has been used to predict the performance of a mixed mode solar dryer for drying coconut. The simulation of neural network is based on the feed forward back propagation algorithm

Methyl (2Z)-2-{[N-(2-formyl­phen­yl)-4-methyl­benzene­sulfonamido]­meth­yl}-3-(naphthalen-1-yl)prop-2-enoate

In the title compound, C29H25NO5S, the sulfonyl-bound benzene ring forms dihedral angles of 42.1 (1) and 48.5 (1)°, respectively, with the formyl-substituted benzene ring and the naphthalene residue. In the crystal, pairs of C—H⋯O inter­actions lead to the formation of R 2 2(10) inversion dimers, which are linked by further C—H⋯O inter­actions into supra­molecular tapes running along [100]. The crystal packing is further stabilized by C—H⋯π inter­actions

Life Cycle cost Analysis of Waste Heat Operated Absorption Cooling Systems for Building HVAC Applications

In this paper, life cycle cost analysis (LCCA) of waste heat operated vapour absorption air conditioning system (VARS) incorporated in a building cogeneration system is presented and discussed. The life cycle cost analysis (LCCA) based on present worth cost (PWC) method, which covers the initial costs, operating costs, maintenance costs, replacement costs and salvage values is the useful tool to merit various cooling and power generation systems for building applications. A life cycle of 23 years was used to calculate the PWC of the system for annual operating hours of 8760 and the same is compared with the electric based vapour compression chiller (VCRS) of same capacity. The life cycle cost (LCC) of waste heat operated absorption chiller is estimated to be US $ 1.5 million which is about 71.5 % low compared to electric powered conventional vapour compression chiller. From the analysis it was found that the initial cost of VARS system was 125 % higher than that of VCRS, while the PWC of operating cost of VARS was 78.2 % lower compared to VCRS. The result shows that the waste heat operated VARS would be preferable from the view point of operating cost and green house gas emission reduction

Extended metal-organic solids based on benzenepolycarboxylic and aminobenzoic acids

This article describes the recent results obtained in our laboratory on the interaction of polyfunctional ligands with divalent alkaline earth metal ions and a few divalent transition metal ions. Treatment of MC12·nH2O (M = Mg, Ca, Sr or Ba) with 2-amino benzoic acid leads to the formation of complexes [Mg(2-aba)2] (1), [Ca(2-aba)2(OH2)3]∞ (2), [{Sr(2-aba)2(OH2)2}2·H2O)]∞ (3), [Ba(2-aba)2(OH2)]∞ (4), respectively. While the calcium ions in 2 are hepta-coordinated, the strontium and barium ions in 3 and 4 reveal a coordination number of nine apart from additional metal-metal interactions. Apart from the carboxylate functionality, the amino group also binds to the metal centres in the case of strontium and barium complexes 3 and 4. Complexes [{Mg(H2O)6}(4-aba)2·2H2O] (5), [Ca(4-aba)2(H2O)2] (6) prepared from 4-aminobenzoic acid reveal more open or layered structures. Interaction of 2-mercaptobenzoic acid with MCl2·6H2O (M = Mg, Ca), however, leads to the oxidation of the thiol group resulting in the disulphide 2,2' -dithiobis(benzoic acid). New metal-organic framework based hydrogen-bonded porous solids [{M(btec) (OH2)4}n·n(C4H12N2)·4nH2O] (btec = 1,2,4,5-benzene tetracarboxylate) (M = Co9; Ni10; Zn11) have been synthesized from 1,2,4,5-benzene tetracarboxylic acid in the presence of piperazine. These compounds are made up of extensively hydrogen-bonded alternating layers of anionic M-btec co-ordination polymer and piperazinium cations. Compounds 2- 11 described herein form polymeric networks in the solid-state with the aid of different coordinating capabilities of the carboxylate anions hydrogen bonding interactions

(Z)-Methyl 2-[(4-bromo-2-formyl­phen­oxy)meth­yl]-3-o-tolyl­acrylate

In the title compound, C19H17BrO4, the dihedral angle between the two benzene rings is 82.1 (1)°. The mol­ecular structure is stabilized by an intra­molecular C—H⋯O hydrogen bond which generates an S(7) ring motif. The crystal packing is stabilized by inter­molecular C—H⋯O hydrogen bonds and C—H⋯π inter­actions. Inter­molecular C—H⋯O inter­actions are involved in the formation of centrosymmetric R 2 2(16) dimers, which are connected into supra­molecular tapes running along the [100] direction