Decationization and dealumination of clinoptilolite tuff and ammonium exchange on acid-modified tuff

The paper presents results of investigation of exchange of the clinoptilolite tuff cations with hydrogen ions from HCl solution of concentration 0.1 mmol cm(-3) and ammonium ions solutions of concentrations 0.0071 to 2.6 mmol cm(-3). Molal concentrations, x (mmol g(-1)) of cations exchanged in acid solution and in ammonium ions solutions were compared with molal concentrations of cations obtained by determination of the cation-exchange capacity of clinoptilolite tuff. The obtained results show that at ammonium ion concentrations lower than 0.1 mmol cm(-3), with regard to exchange capacity for particular ions, best exchanged are Na+ ions, followed by Mg2+ and Ca2+ ions, while exchange of K+ ions is the poorest (Na+ > Mg2+ > Ca2+ > K+). At ammonium concentrations from 0.2 to 1 mmol cm(-3) the order is Na+ > Ca2+ > Mg2+ > K+. At concentrations higher than 1 mmol cm(-3) the order is Na+ > Ca2+ > K+ > Mg2+. The results are a consequence of the uptake of hydrogen ions by zeolite samples in ammonium ions solutions at concentrations lower than 1 mmol cm(-3) and indicate the importance of Mg2+ (besides Na+ ions) for the exchange between clinoptilolite cations and H+ ions, in contrast to K+ ions, whose participation in the reaction with H+ ions is the lowest. During decationization of the clinoptilolite in acid solution, best exchanged are Na+, Mg2+, and Ca2+ ions, while exchange of K+ ions is the poorest. Due to poor exchange of K+ and H+ ions and good exchange of Na+, Mg2+, and Ca2+ ions, it is to be assumed that preservation of stability of the clinoptilolite structure is caused by K+ ions present in the channel C. Clinoptilolite is dissolved in the clinoptilolite A and B channels where Na+, Mg2+, and Ca2+ ions are present. On the acid-modified clinoptilolite samples, exchange of ammonium ions is poorer than on natural zeolite. The longer the contact time of the zeolite and acid solution, the worse ammonium ions exchange. It can be assumed that H+ ions exchanged with zeolite cations are consumed for solution of aluminum in the clinoptilolite structure; therefore the concentration of H+ ions as exchangeable cations decreases. In the ammonium ion solution at a concentration of 0.0065 mmol cm(-3), from the acid-modified zeolite samples, Al3+ ions are exchanged best, followed by Na+, Mg2+, Ca2+, and K+ ions. Further to the results, it is to be assumed that exchangeable Al3+ ions available from clinoptilolite dissolution are best exchanged with H+ ions in acid solution.     

健康维吾尔人微核率的测定

采用薛开先的“人体末梢血微核率测试法”，检测了没有接触过任何诱变剂的１００个健康维吾尔人末梢血淋巴细胞２０００００个，检测出有２７个微核，激核率为０．１４‰．不同年龄组微核率的分布范围为０～１，各组平均微核率之间没有显著性差异（Ｐ＞０．０５），微核在不同性别的健康维吾尔人群中的分布范围也是０～１‰，平均微率率在不同性别之间也同样无显著性差异（μ＝０．５，Ｐ＞０．０５）．因此，从健康维吾尔人群中检测出来的微核率，可作为确定健康的一项指标，这对医学、环境研究以及诱变致癌因子的遗传毒理学检测有重要意义．     

Copper-containing monodisperse mesoporous silica nanospheres by a smart one-step approach

Copper-containing mesoporous silica spheres of size in the colloidal range with perfect conservation of pore-ordering, shape and monodispersity and high intra-pore metal dispersion were prepared via a new one-step synthesis and functionalisation route.     

Monolithic Gels of Silica and Nonionic Surfactant: Matrices for the Dispersion of Metal Ions

The formation of homogeneous monolithic gels by the addition of TEOS to acidic amphiphilic solutions has been investigated for a range of nonionic surfactants, and the relationships between solution composition and gelation examined. Using the surfactant solutions as a means of pre-doping the matrices with high concentrations of manganese nitrate gave gels which could be calcined to 400°C with little or no segregation of manganese oxide observed by X-ray diffraction. X-ray absorption spectroscopy has shown that the ligand environment of manganese in the silica-surfactant matrices differs from that in gels derived from ethanol solutions, and that most of the manganese in the calcined gels remains in a disordered environment.     

Incoherent inelastic neutron scattering of the strong (NHN) bond in H3Co(CN)6

The vibrations of the strong symmetric NHN hydrogen bond in H₃Co(CN)₆ have been investigated by inelastic neutron scattering spectroscopy at 80 K. The two deformation modes δ(NH) and γ(NH) have been identified. A strong protonic mode is observed in the low energy transfer region and is assigned to the antisymmetric stretching vibration of the hydrogen bond. Relative intensities of the ν(NH) fundamental, its first overtone and bending fundamentals are interpreted as suggesting a strongly anisotropic Debye-waller factor. At 5 K the ν(NH) fundamental shows a complex structure which is interpreted in terms of coupling with low frequency lattice modes.     

Numerical modeling on inlet aperture effects on flow pattern in primary settling tanks

Inlets should be designed to dissipate the kinetic energy or velocity head of the mixed liquor and to prevent short-circuiting, mitigate the effects of density currents, and minimize blanket disturbances. Flow in primary settling tank is simulated by means of computational fluid dynamics. The fluid is assumed incompressible and non-buoyant. A two-dimensional computational and one phase fluid dynamics model was built to simulate the flow properties in the settling tank including the velocity profiles, the flow separation area and kinetic energy. In this study, the RNG turbulent model was solved with the Navier–Stokes equations. In order to evaluate hydraulic influences on the velocity profile, separation length and kinetic energy, three different of opening positions and two and three aperture in inlets were simulated. The flow model uses to apply a fixed-grid of cells that are all rectangular faces; the fluid moves through the grid and free surfaces are tracked with the volume-of-fluid (VOF) technique. Effects of numbers and locations of inlet apertures on the flow field are presented and the results show the positions of inlet apertures are affected on the flow pattern in the settling basin and increasing the numbers of slots can reduce kinetic energy in the inlet zone and produce uniform flow.     

Safety assessments of subcutaneous doses of aragonite calcium carbonate nanocrystals in rats

Calcium carbonate nanoparticles have shown promising potentials in the delivery of drugs and metabolites. There is however, a paucity of information on the safety of their intentional or accidental over exposures to biological systems and general health safety. To this end, this study aims at documenting information on the safety of subcutaneous doses of biogenic nanocrystals of aragonite polymorph of calcium carbonate derived from cockle shells (ANC) in Sprague-Dawley (SD) rats. ANC was synthesized using the top-down method, characterized using the transmission electron microscopy and field emission scanning electron microscope and its acute and repeated dose 28-day trial toxicities were evaluated in SD rats. The results showed that the homogenous 30 ± 5 nm-sized spherical pure aragonite nanocrystals were not associated with mortality in the rats. Severe clinical signs and gross and histopathological lesions, indicating organ toxicities, were recorded in the acute toxicity (29,500 mg/m²) group and the high dose (5900 mg/m²) group of the repeated dose 28-day trial. However, the medium- (590 mg/m² body weight) and low (59 mg/m²)-dose groups showed moderate to mild lesions. The relatively mild lesions observed in the low toxicity dosage group marked the safety margin of ANC in SD rats. It was concluded from this study that the toxicity of CaCO₃ was dependent on the particulate size (30 ± 5 nm) and concentration and the route of administration used.     

An Embedded 3D Strain Tensor Sensor Based on the Eshelby’s Inclusion

A new design for an embedded strain sensor is proposed in this paper. Based on Eshelby’s inclusion model, it may be used to measure the full 3D strain or stress tensor within any solid body. Currently, common embedded strain sensors are only capable of 1D measurements. The spherical shape of our sensor allows the stress or strain that would exist in the structure without the sensor to be calculated with the aid of the Eshelby theorem (in the case of elastic behavior). We used fiber Bragg gratings to measure the deformation of the sphere - other techniques are also available. Experimental testing was performed in two settings. The first test measured the performance of a polymethylmethacrylate prototype under fluid pressure load. In a second test, a steel prototype sensor was embedded in a standardized concrete specimen under axial compression, and was successfully used to measure 3D strain in real conditions.     

Effect of side‐chain length on the electrospinning of perfluorosulfonic acid ionomers

The effect of the side‐chain length (short side chain and long side chain, SSC and LSC, respectively) of perfluorosulfonic acid (PFSA) ionomers on the properties of nanofibers obtained by electrospinning ionomer dispersions in high dielectric constant liquids has been investigated with a view to obtaining electrospun webs as components of fuel cell membranes. Ranges of experimental conditions for electrospinning LSC and SSC PFSAs have been explored, with a scoping of solvents, carrier polymer and PFSA ionomer concentrations, and carrier polymer molecular weight. Under optimal conditions, the electrospun mats derived from SSC and from LSC PFSA show distinct fiber dimensions that arise from the different chain lengths of the respective ionomers. Enhanced interchain interactions in SSC PFSA with low equivalent weight compared to LSC PFSA result in a considerably lower average fiber diameter and a markedly narrower fiber size distribution. The proton conductivity of nanofiber mats of SSC and LSC PFSA with equivalent weights of 830 and 900 g mol^?1, respectively, are 102 and 58 mS cm^?1 at 80°C and 95% relative humidity. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013