49 research outputs found
A Reitveld quantitative XRD phase-analysis of selected composition of the Sr (0.5+x)
Qualitative XRD phase-analysis of four (x = 0.10, 0.20, 0.30, 0.40) selected compositions of the Sr(0.5+x)Sb(1−x)Fe(1+x)(PO4)3(0 < x < 0.50) system was undertaken. XRD data shows the absence of a continuously solid solution. In fact, each composition is composed only of a mixture of the two end members, Sr0.50SbFe(PO4)3 (R See Formula in PDF space group) and SrSb0.50Fe1.50(PO4)3 (R See Formula in PDF c space group), type-phases. Rietveld refinement method, using the XRPD technique, has been used for a quantitative phase-analysis of these compositions. In order to evaluate the relative errors of this experimental result, a set of standard phase-mixtures of both end compositions of the system was also quantified by the Rietveld method. Obtained results show the usefulness of this method for quantitative phase-analysis, particularly in geology including other classes of materials such clay and cement
A new langbeinite-type phosphate: K2AlSn(PO4)3
Single crystals of the title compound, dipotassium aluminium tin(IV) tris[phosphate(V)], K2AlSn(PO4)3, were synthesized by a high temperature reaction in a platinum crucible. In the structure, the AlIII and SnIV atoms occupy the same site on a threefold rotation axis with occupational disorder in a 1:1 ratio. In the three-dimensional structure, Al/SnO6 octahedra and PO4 tetrahedra are interconnected via their vertices, yielding a [Al/SnP3O12]n framework. The K atoms (site symmetry 3) reside in the large cavities delimited by the [Al/SnP3O12]n framework, and are surrounded by 12 O atoms
Al0.5Nb1.5(PO4)3
Single crystals of the title compound, aluminium niobium triphosphate, Al0.5Nb1.5(PO4)3, have been synthesized by a high-temperature reaction in a platinium crucible. The AlIII and NbV atoms occupy the same site on the axis, with disorder in the ratio of 1:3. The fundamental building units of the title structure are isolated Al/NbO6 octahedra and PO4 tetrahedra (. 2 symmetry), which are further interlocked by corner-sharing O atoms, leading to a three-dimensional framework structure with infinite channels along the a axis
Investigation on the behavior of wastewater from industrial cooling water systems
Industrial wastewater is discharged from industries and associated processes utilizing water. Industrial water cooling systems generated large amount wastewater. Industrial water cooling systems produce waste such as silt, heat, biocide and slimes. The problems need to be controlled or eliminated are at interferes with heat, commonly referred to as deposits and deterioration of the water-contacted equipment, referred to as corrosion. Therefore, this research is carried out to overcome this problem by determine the behavior of wastewater from industrial water cooling systems and determine the influence of concentration of Acid Hydrochloric in water cooling systems during Passivation process. The parameters considered based on APHA method in Standard Methods for Examination of Water and Wastewater (2005) are including Chemical Oxygen Demand (COD), Total Organic Carbon (TOC), pH, Turbidity, Heavy Metals (Iron, Lead, Copper, Nitrate and Nickel). The study of behavior of wastewater from industrial water cooling systems will be taken place at behind the block W, Universiti Malaysia Pahang, Campus Gambang, Pahang Darul Makmur. The results show that all parameters except lead are recorded to be over than standard that have been use for comparison purpose such as the highest concentration of iron recorded that 3012 mg/L but the standard is 5 mg/L. As a conclusion, this effluent need proper treatment before been discharge because majority of parameters over than standard propose. According to study of concentration of Acid Hydrochloric (HCl) can affect the efficiency of passivation for Carbon Steel pipe. For concentration HCl 2 %, passivator needs to increase from 0.1% to 1.0% and pH also not exceed to alkali conditions or not in range 10-12 for effective passivation
ChemInform Abstract: Structure, Infrared and Raman Spectroscopic Studies of Newly Synthetic A II
Synthesis and Crystal Structure of the New Perovskite CaLa2CaTi2O9 (= (Ca1/3La2/3)A (Ca1/3Ti2/3)BO3).
A Study on Multi-Path Channel Response of Acoustic Propagation in Northwestern Arabian Sea
Abstract: Multi-path interference due to boundary reflection and variation of sound speed profile in underwater water acoustic communication pose the major barrier to reliable high-speed underwater communication system. Based on the sound speed profiles and the bathymetry data of northwestern Arabian Sea, Multipath impulse response profiles of the area have been obtained using Bellhop. The derived parameters like delay structure, effective transmit and receive angles suitable depths etc. from the obtained impulse responses have also been discussed. The impulse responses have been obtained for different scenarios of transmitter and receiver geometry to arrive at optimal configuration of wireless Acoustic communication/telemetry system for that area. This work can be used as a guide for the practical design of underwater acoustic wireless communication/telemetry system to be operated in this area which is critical to world oil exports
Crystalline Iron Oxohalide Nanotube Pea Pods
Compounds Fe7Sb3(PO4)3O6Cl3 and Fe7Sb3(PO4)3O6Br3 are the first iron phosphates containing SbIII. They were synthesized by chemical vapor transport reactions, and their crystal structures were characterized by single-crystal X-ray diffraction. The compounds are isostructural and crystallize in the orthorhombic space group Pnma. Tubular Fe7(PO4)3O6X3 units (X = Cl, Br) are linked by SbO4 groups to build up a framework. The tubular units consist of an outer part made up of [FeO5X] octahedra where the Fe atoms are arranged to resemble a nanotube. Inside the tubes there are phosphate groups, and at the very center there is a chain of face-sharing [FeO6] octahedra
Raman and FTIR studies of the structural aspects of Nasicon-type crystals; AFeTi(PO4)3 [A ¼ Ca, Cd]
Raman and FTIR spectra of CaFeTi(PO4)3 and CdFeTi(PO4)3 are recorded and analyzed. The observed bands are assigned in terms
of vibrations of TiO6 octahedra and PO4 tetrahedra. The symmetry of TiO6 octrahedra and PO4 tetrahedra is lowered from their free ion
symmetry. The presence of Fe3+ ion disrupts the Ti–O–P–O–Ti chain and leads to the distortion of TiO6 octrahedra and PO4 tetrahedra.
The PO4 3 tetrahedra in both crystals are linearly distorted. The covalency bonding factor of PO4 3 polyanion of both the crystals are
calculated from the Raman spectra and compared to that of other Nasicon-type systems. The numerical values of covalency bonding
factor indicates that there is a reduction in redox energy and cell voltage and is attributed to strong covalency of PO4 3 polyanioninJournal of Physics and Chemistry of Solids 69 (2008) 1985–198