Electric-Field Gradient at Cd Impurities in In2o3. A FLAPW Study

We report an ab initio study of the electric-field gradient tensor (EFG) at Cd impurities located at both inequivalent cationic sites in the semiconductor In2O3. Calculations were performed with the FLAPW method, that allows us to treat the electronic structure of the doped system and the atomic relaxations introduced by the impurities in the host lattice in a fully self-consistent way. From our results for the EFG (in excellent agreement with the experiments), it is clear that the problem of the EFG at impurities in In2O3 cannot be described by the point-charge model and antishielding factors.Comment: 4 pages, 2 figures, and 2 table

Chemical characterization and economic evaluation of the coal fly ash pre-washing and carbonation process

In the present laboratory-scale study, the combination of washing and carbonation processes was examined to evaluate the feasibility to reduce the environmental impact of coal power plants. Three different washing solutions (tap, distilled and sea water) were used to pre-treat coal fly ash and the corresponding effect on direct gas-solid carbonation and final metal leaching was evaluated. Finally, a preliminary economic evaluation of the process was performed. In terms of captured CO2, the results have shown that significant amounts can be captured, although, as expected, the leaching of soluble salts in water such as Ca and Mg reduce the CO2 uptake. In terms of heavy metal's leaching, the application of pre-washing and carbonation treatment significantly affected the metal immobilization on the final residue. The pre-washing with sea water allowed to reach a sensible improvement since only selenium, chlorides and sulphates resulted outside the range for disposing of the carbonated residue in landfill for non-hazardous waste

Keberhasilan Inseminasi Buatan Menggunakan Semen Beku Dan Semen Cair Pada Sapi Peranakan Ongole

The purpose of this research was to know about the successfully artificial insemination (AI) using frozen and liquid semen of Ongole cross (PO) cattle indicated by Service per Conception (S/C), Days Open (DO) dan Conception Rate (CR). The materials used were 60 heads of Ongole crossbred cattle which were selected purposively using some criteria, such as having calving experience, healthy, and free from any reproduction disorder. This field experiment consisted of direct observation and interview to acquire primary and secondary data. Datas were analyzed descriptively and continued by a paired t-test. The results showed that the value of (S/C) was very significantly different (P<0.01), DO was not significantly different (P>0.05). CR for P1, P2, P3, and P4 was found 63.33% , 86.67%, 16.33%, 83.33% respectively. The conclusion of this research was AI using frozen and liquid semen with only 5 days preservation had a difference on the value of service per conception. The most successfull AI was found higher in the liquid semen which was stored for 1 and 5 days than that of frozen semen

The problem of a metal impurity in an oxide: ab-initio study of electronic and structural properties of Cd in Rutile TiO2

In this work we undertake the problem of a transition metal impurity in an oxide. We present an ab-initio study of the relaxations introduced in TiO2 when a Cd impurity replaces substitutionally a Ti atom. Using the Full-Potential Linearized-Augmented-Plane-Wave method we obtain relaxed structures for different charge states of the impurity and computed the electric-field gradients (EFGs) at the Cd site. We find that EFGs, and also relaxations, are dependent on the charge state of the impurity. This dependence is very remarkable in the case of the EFG and is explained analyzing the electronic structure of the studied system. We predict fairly anisotropic relaxations for the nearest oxygen neighbors of the Cd impurity. The experimental confirmation of this prediction and a brief report of these calculations have recently been presented [P.R.L. 89, 55503 (2002)]. Our results for relaxations and EFGs are in clear contradiction with previous studies of this system that assumed isotropic relaxations and point out that no simple model is viable to describe relaxations and the EFG at Cd in TiO2 even approximately.Comment: 11 pages, 8 figures, Revtex 4, published in Physical Review

Analysis of hybrid separation schemes for levulinic acid separation by process intensification and assessment of thermophysical properties impact

From the time levulinic acid was listed as one of the top-12 building blocks for the sugars-high value compounds conversion, the interest in this compound increased. As part of its possible production route, the definition of viable separation schemes appears of paramount importance in the overall development of levulinic acid exploitation. Hybrid sequences where liquid-liquid extraction is followed by distillation were considered proving how the direct and direct-indirect separation schemes appeared to be the best alternatives in terms of total annual cost and environmental impact. These alternatives were further analyzed to improve their design by complementing the process simulator database with thermophysical experimental values. After obtaining a reliable design for the hybrid direct and direct-indirect configurations used as benchmarks, two intensified al-ternatives were generated. The first intensified configuration is classified as thermodynamically equivalent sequence, while the second one includes a divided wall column. For both, it was achieved a reduction of the total annual cost of 11% without any penalty for the environmental impact compared to the reference case

First-principles study of orthorhombic CdTiO3 perovskite

In this work we perform an ab-initio study of CdTiO3 perovskite in its orthorhombic phase using FLAPW method. Our calculations help to decide between the different cristallographic structures proposed for this perovskite from X-Ray measurements. We compute the electric field gradient tensor (EFG) at Cd site and obtain excellent agreement with available experimental information from a perturbed angular correlation (PAC) experiment. We study EFG under an isotropic change of volume and show that in this case the widely used "point charge model approximation" to determine EFG works quite well.Comment: 4 pages, 1 figure. Accepted in Physical Review

Progress and status of APEmille

We report on the progress and status of the APEmille project: a SIMD parallel computer with a peak performance in the TeraFlops range which is now in an advanced development phase. We discuss the hardware and software architecture, and present some performance estimates for Lattice Gauge Theory (LGT) applications.Comment: Talk presented at LATTICE97, 3 pages, Late

Hydrated metal salt pretreatment and alkali catalyzed reactive distillation: A two-step production of waste cooking oil biodiesel

In this work, a novel method was proposed for the conversion of waste cooking oil into biodiesel. A two-step approach based on a pretreatment with AlCl3•6H2O to convert FFA into the relevant methyl esters, followed by the complete transesterification of glycerides, under KOH catalysis in a reactive distillation column, was considered. The pretreatment with AlCl3•6H2O allowed to obtain two different phases: an oily phase, rich in FAME and triacylglycerols and with a very limited content of water (100 ppm), and residual FFA (1 mgKOH /goil), and a methanol phase, in which most of the catalyst, water and monoacylglycerols were dissolved in. The esterified stream was characterized by its composition and used to obtain new kinetic parameters to be used in the setting of the reactive distillation. The reactive distillation column was proved to be efficient in obtaining a biodiesel stream with a purity requirement conform to the EN14214 standards. The transesterification step was characterized by a specific heating requirement of 701.3 kJ per kg of biodiesel produced

Machine Learning algorithm unveils glutamatergic alterations in the post-mortem schizophrenia brain

Schizophrenia is a disorder of synaptic plasticity and aberrant connectivity in which a major dysfunction in glutamate synapse has been suggested. However, a multi-level approach tackling diverse clusters of interacting molecules of the glutamate signaling in schizophrenia is still lacking. We investigated in the post-mortem dorsolateral prefrontal cortex (DLPFC) and hippocampus of schizophrenia patients and non-psychiatric controls, the levels of neuroactive d- and l-amino acids (l-glutamate, d-serine, glycine, l-aspartate, d-aspartate) by HPLC. Moreover, by quantitative RT-PCR and western blotting we analyzed, respectively, the mRNA and protein levels of pre- and post-synaptic key molecules involved in the glutamatergic synapse functioning, including glutamate receptors (NMDA, AMPA, metabotropic), their interacting scaffolding proteins (PSD-95, Homer1b/c), plasma membrane and vesicular glutamate transporters (EAAT1, EAAT2, VGluT1, VGluT2), enzymes involved either in glutamate-dependent GABA neurotransmitter synthesis (GAD65 and 67), or in post-synaptic NMDA receptor-mediated signaling (CAMKIIα) and the pre-synaptic marker Synapsin-1. Univariable analyses revealed that none of the investigated molecules was differently represented in the post-mortem DLPFC and hippocampus of schizophrenia patients, compared with controls. Nonetheless, multivariable hypothesis-driven analyses revealed that the presence of schizophrenia was significantly affected by variations in neuroactive amino acid levels and glutamate-related synaptic elements. Furthermore, a Machine Learning hypothesis-free unveiled other discriminative clusters of molecules, one in the DLPFC and another in the hippocampus. Overall, while confirming a key role of glutamatergic synapse in the molecular pathophysiology of schizophrenia, we reported molecular signatures encompassing elements of the glutamate synapse able to discriminate patients with schizophrenia and normal individuals

Potts models in the continuum. Uniqueness and exponential decay in the restricted ensembles

In this paper we study a continuum version of the Potts model. Particles are points in R^d, with a spin which may take S possible values, S being at least 3. Particles with different spins repel each other via a Kac pair potential. In mean field, for any inverse temperature there is a value of the chemical potential at which S+1 distinct phases coexist. For each mean field pure phase, we introduce a restricted ensemble which is defined so that the empirical particles densities are close to the mean field values. Then, in the spirit of the Dobrushin Shlosman theory, we get uniqueness and exponential decay of correlations when the range of the interaction is large enough. In a second paper, we will use such a result to implement the Pirogov-Sinai scheme proving coexistence of S+1 extremal DLR measures.Comment: 72 pages, 1 figur