Ignite-GPU: a GPU-enabled in-memory computing architecture on clusters

The Journal of Supercomputing - During recent years, big data explosion and the increase in main memory capacity, on the one hand, and the need for faster data processing, on the other hand, have...     

New block copolymers II. Synthesis and characterization of an ABA-type block copolymer

A new regular ABA-type triblock copolymer has been synthesized by polycondensation of the acid chloride of carboxy-terminated butadience-acrylonitrile rubber (CTBN) with hydroxyterminated polyethylene isophthalate (PEI) oligomer. This block copolymer was characterized by elemental (nitrogen) analysis, vapor pressure osmometry, viscometry, and IR and NMR spectroscopy. Quantitative estimation of block segments has been carried out by measuring the area under peaks assigned to various protons in the NMR spectrum of the polymer. NMR spectral analysis has been found to agree well with the nitrogen analysis of the polymer. The solubility and solution viscosity behavior of the polymer has also been studied.     

Synthesis and dissolution behavior of nanosized silicon and magnesium co-doped fluorapatite obtained by high energy ball milling

Nanosized hydroxyapatite (HA) powders exhibit a greater surface area than coarser crystals and are expected to show an improved bioactivity. In addition, properties of HA can be tailored over a wide range by incorporating different ions into HA lattice. The aim of this study was to prepare and characterize silicon and magnesium co-doped fluorapatite (Si–Mg–FA) with a chemical composition of Ca_9.5Mg_0.5 (PO₄)_5.5(SiO₄)_0.5F₂ by the high-energy ball milling method. Characterization techniques such as X-ray diffraction analysis (XRD), Fourier transformed infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM) were utilized to investigate the structural properties of the obtained powders. Dissolution behavior was evaluated in simulated body fluid (SBF) and physiological normal saline solution at 37 °C for up to 28 days. The results of XRD and FTIR showed that nanocrystalline single-phase Si–Mg–FA powders were synthesized after 12 h of milling. In addition, incorporation of magnesium and silicon into fluorapatite lattice decreased the crystallite size from 53 nm to 40 nm and increased the lattice strain from 0.220% to 0.296%. Dissolution studies revealed that Si–Mg–FA in comparison to fluorapatite (FA), releases more Ca, P and Mg ions into SBF during immersion. 175 ppm Ca, 33.5 ppm P and 48 ppm Mg were detected in the SBF containing Si–Mg–FA after 7days of immersion, while for FA, it was 75 ppm Ca, 21.5 ppm P and 29 ppm Mg. Release of these ions could improve the bioactivity of the obtained nanopowder. It could be concluded that the prepared nanopowders have structural properties such as crystallite size (~40 nm), crystallinity degree (~40%) and chemical composition similar to biological apatite. Therefore, prepared Si–Mg–FA nanopowders are expected to be appropriate candidates for bone substitution materials and also as a phase in polymer or ceramic-based composites for bone regeneration in tissue engineering applications.     

The reaction of sulphur dioxide with water and a halogen. The case of iodine: reaction in presence of organic solvents

Experimental work on the reaction of SO₂, H₂O and I₂ is described in this paper. This reaction gives rise to separation problems which may be overcome by the use of a large excess of SO₂ and/or by the addition of suitable organic solvents. The results obtained with SO₂ only and with addition of diethylether and TBP are discussed, also in view of application of this reaction in possible thermochemical cycles.     

Detection of the 1H and 15N NMR resonances of sulfamate groups in aqueous solution: a new tool for heparin and heparan sulfate characterization

Sulfamate (NHSO(3)(-)) groups are critically important structural elements of the glycosaminoglycans heparin and heparan sulfate (HS). Experimental conditions are presented for detection of the sulfamate (1)H NMR resonances in aqueous solution. NMR spectra reported for N-sulfoglucosamine (GlcNS) and the synthetic pentasaccharide drug fondaparinux demonstrate the broad utility of the sulfamate group (1)H chemical shifts to reflect differences in molecular structure. The sulfamate protons also provide an efficient route for detection of (15)N chemical shifts through proton-nitrogen correlations measured with the heteronuclear single quantum coherence (HSQC) experiment. The HSQC spectra of GlcNS, fondaparinux, and the low-molecular weight heparin enoxaparin illustrate the power of the (1)H and (15)N chemical shifts of the sulfamate NH groups for the structural characterization of heparin and HS.     

Investigation of ITS-90 Inconsistencies in Overlap Region of the Water-indium,Water-tin,and Water-zinc Sub-ranges

One of the significant uncertainties in Standard Platinum Resistance Thermometer (SPRT) calibration by fixed-points method is Type I non-uniqueness (sub-range inconsistencies). Sub-ranges water-tin (W ₉ ) and water-indium (W ₁₀ ) lies in the water-zinc (W ₈ ) sub-range of the International Temperature Scale of 1990. Therefore, three sub-range inconsistencies [W ₈ and W ₉ (SRI _8–9 ), W ₈ and W ₁₀ (SRI _8–10 ), and W ₉ and W ₁₀ (SRI _9–10 )] occur. This paper investigated these inconsistencies using the calibration data of 12 SPRTs from six manufacturers. The result shows that the magnitude of the inconsistency for SRI _8–9 , SRI _8–10 , and SRI _9–10 are about 2.5, 2.2 and 1.8 mK, respectively.     

Developing three-dimensional mesh-free Galerkin method for structural analysis of general polygonal geometries

Engineering with Computers - In this paper, triangular prismatic cells for background integration on mesh-free methods are introduced and the Gauss integration scheme is developed in these...     

Using Modified Couple Stress Theory for Modeling the Size-Dependent Pull-In Instability of Torsional Nano-Mirror under Casimir Force

It is well-established that mechanical response of nanostructures is size-dependent. In this article, the size-dependent pull-in instability of rotational nano-mirror is investigated using modified couple stress theory. The governing equation of the mirror is derived taking the effect of electrostatic Coulomb and Casimir forces into account. Effect of finite conductivity of material is included in the Casimir formulation. Variation of the rotation angle of the mirror as a function of the applied voltage is obtained and the instability parameters i.e., pull-in voltage and pull-in angle of the system are determined. The effect of Casimir forces on the size-dependent pull-in instability of the system is discussed. Furthermore, the minimum gap between the mirror and the ground to prevent stiction (due to Casimir force) is determined as a function of material length scale parameter. It is found that the proposed model is able to predict the experimental results more accurately than the previous classical models and reduces the gap between previous theories and experiments.