Study of human cortical bone and demineralized human cortical bone viscoelasticity

The knowledge of human bone viscoelasticity is an important issue for defining semirigid calcified tissues implants. A very sensitive technique was used to investigate bone viscoelasticity: the thermally stimulated creep method. A study of demineralized human bone was performed to determine the molecular origin of bone viscoelasticity. The thermally stimulated creep spectra of bone and demineralized bone, at the hydrated state, present a similar shape with one main retardation mode located at −133 and −120°C, respectively. This mode is shifted toward higher temperatures after dehydration, revealing the existence of another mode at around −155°C. The analysis of elementary spectra of bone and demineralized bone has shown that retardation times follow an Arrhenius equation, and that two compensation phenomena are observed with comparable compensation parameters. The first compensation phenomenon, which corresponds to the main retardation mode, was attributed to motions of water molecules located inside the collagen triple helix. The second compensation phenomenon, which reveals the existence of another relaxation mode at higher temperatures, was assigned to movements of hydrophilic side chains bound to water molecules. As for the mode observed at around −155°C, it was associated with motions of aliphatic side chains. Overall, bone viscoelasticity originates from the organic matrix. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2527–2533, 2001     

Effect of demineralization of El-lajjun Jordanian oil shale on oil yield

The effect of demineralization on oil yield and mineral composition of Jordanian oil shale was investigated. A standard digestion procedure using a range of inorganic and organic acids including HCl, HNO₃, HF, and CH₃COOH was used to enhance the oil recovery of oil shale samples collected from the El-lajjun area. The total yield of the digested samples, as determined by Fischer Assay, has shown a maximum value (two folds the untreated sample) obtained when using CH₃COOH. The kaolin in the treated oil shale with a high concentration of CH₃COOH is believed to have transformed to illite as found in the XRD analysis. The treatment of oil shale using HCl has shown an increased ratio of oil to gas as a result of the digestion of calcite in the oil shale. At higher concentrations of HNO₃, the acid is believed to react with the kerogen in the oil shale resulting in high levels of low molecular weight compounds. Therefore, the amount of non-condensable gases produced by Fischer assay after treatment with a high concentration of HNO₃ is relatively high. HF is believed to drive off water from the oil shale by dissolving the clay minerals leading to increased oil to gas ratio.     

Kerogen chemistry 5. Anhydride formation in,solvent swelling of,and loss of organics on demineralization of Kimmeridge shales

The results of three short and related, but experimentally independent, studies of 4 Kimmeridge shales and their kerogens are reported. Differential scanning calorimeter (DSC) studies of the kerogens reveal that three of the four show evidence of anhydride formation when heated at 20 °C/min between 50 °C and 180 °C. There is no regular rank dependence of anhydride formation. After solvent swelling in tetrahydrofuran (THF), extracted organics were isolated from the THF and the recovered kerogens were swollen a second time in fresh THF. The second solvent swelling ratios were slightly larger than the first because the presence of the extracts in the original THF lowers solvent activity thus reducing swelling. The shales were demineralized in the usual way except that methylene chloride was added to dissolve any organics that were liberated from the rock as a consequence of mineral dissolution. Small amounts of organics were found in the methylene chloride supporting Price and Clayton's conclusion that organics are expelled from the kerogen and are present in lacunae in the minerals.     

盐酸波美测浓装置探讨

１　现行盐酸波美测浓装置简介现行盐酸波美测浓装置主要有间歇式和连续式。间歇式是将波美测浓装置安装在产品盐酸的管道上,位置一般在操作室观察不到,安装方式如图１所示。测量浓度是由操作人员在巡回检查时通过调节有关阀门,先向装置注酸,测定对应的相对密度和浓度,测完将酸放掉,查表得浓度。１温度计;２波美表;３孔板图１　间歇波美测浓装置安装示意图连续式盐酸波美测浓装置是通过管道引到操作室容易观察到的地方,安装方法如图２。通过阀门调节,让盐酸以稳定的流量连续不断地通过测量装置。波美情况可以在操作室内直接观察,…     

Influence of modified multi-walled carbon nanotubes on the mechanical behavior and toughening mechanism of an environmentally friendly granulated blast furnace slag-based geopolymer matrix

This study aimed to investigate the mechanical behavior of an environmentally friendly granulated blast furnace slag-based geopolymer matrix reinforced with modified multi-walled carbon nanotubes (MWCNTs). The modified MWCNTs were obtained using a modification method combining nitric acid and sulfuric acid and were then dispersed using sodium dodecylsulfate (SDS) as a dispersant. Two types and three concentrations of MWCNTs were mixed directly into the aqueous solution, sonicated, and then mechanically mixed with waste granulated blast furnace slag to form the geopolymer matrix. Raman and Fourier transform infrared (FT-IR) spectroscopy were used to evaluate the ordered structure and crystallization degree of the modified MWCNTs. Then, the dispersity of the modified MWCNTs was characterized using transmission electron microscopy (TEM). The compressive and bending strengths were measured to evaluate the mechanical behavior of specimens. Moreover, the polycondensation products, polycondensation degree, pore structure, and microscopic morphology of the geopolymer matrix were analyzed using X-ray diffraction (XRD), FT-IR spectroscopy, nuclear magnetic resonance (NMR), mercury intrusion porosimetry (MIP), and field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM-EDS). The experimental results showed that the incorporation of 0.1% functionalized MWCNTs had an optimal influence on the fluidity and mechanical behavior. The slump diameters of geopolymers with 0.1% functionalized MWCNTs with and without SDS were increased by 16.3% and 23.5%, respectively, compared with the reference geopolymer matrix. For geopolymer matrix samples at a curing age of 28 d, the compressive strength of geopolymers with 0.1% functionalized MWCNTs with and without SDS were increased by 16.3% and 17.6%, respectively. For the bending strength, the corresponding increases were 17.6% and 18.7%, respectively. It was found that functionalized MWCNTs could increase the degree of polycondensation, leading to a more traditional amorphous N-A-S-H phase, a finer C–S–H phase, more Q⁴ (2Al) and Q⁴ (3Al), and lower porosity. In addition, the propagation of micro-cracks in the geopolymers was inhibited by the incorporation of functionalized MWCNTs.     

甘油含量对热塑性淀粉结构及性能的影响

通过熔融共混的方法制得甘油含量不同的TPS样品,研究了甘油含量对材料的结构与性能产生的影响。对保存在人体正常体温(37℃)及人体感觉较舒适的湿度(50RH%)下的样品老化过程中的各项性能进行测试,为今后TPS在生物材料领域的应用提供依据。XRD测试表明:高甘油含量阻碍导致老化的β-型晶体的生成但利于ν-型晶体的形成,DMTA及力学性能测试结果表明:甘油含量的增加有利于抑制停放过程中Tg的上升,以及由重结晶所导致的相关力学性能的变化。FTIR谱图从分子短程相互作用的角度反映出甘油含量高不利于有序结构的生成,但增加了材料对水的敏感性。各测试结果均表明甘油含量的增加有延缓TPS老化的作用。     

Effect of particle size on the formation of Ti2AlC using combustion synthesis

This paper provides an insight into the effect of particle size of elemental metal powders and carbon source on the formation mechanism of Ti₂AlC MAX-phase ceramic produced by self-propagating high-temperature synthesis (SHS). The effect of titanium, aluminium and carbon particle size on the 2Ti+Al+C→Ti₂AlC reaction, the phase evolution of the final product and the porosity in both the green body and product has been examined. The effect of the carbon source in the form of graphite, carbon black and short carbon fibres on the reaction mechanism is explained. It is found that the particle size of the titanium and aluminium reactants had little effect on the phases formed but affected the green density of the reactants and the porosity in the final product. The carbon source used in the combustion reaction had an influence on the phases formed by the SHS reaction and was influenced by the dispersion of carbon particles and the titanium–aluminium particle contact.     

Structure and properties of titania reinforced nano-hydroxyapatite/gelatin bio-composites for bone graft materials

This work deals with the preparation of ceramic composites to be employed for the development of load bearing bone substitutes, made of inorganic minerals of needle like nano hydroxyapatite [nHAp: Ca₁₀(PO₄)₆(OH)₂] with bioinert titania as a reinforcing phase and gelatin as protein that mimic the natural bone exhibiting improved biomechanical features. As a monolithic, use of nHAp is limited for biomedical applications because of its inherent low fracture toughness and lack of flexibility. Hence, the incorporation of ceramics such as alumina, zirconia and titania is considered necessary to boost its mechanical properties. The composites of nHAp/TiO₂/gelatin in different weight percentage were prepared by phase separation technique. The identification and morphology of chemically synthesized nHAp particles were determined by XRD, FTIR and SEM analyses. The porosity of scaffolds varied from 77% to 82%. FTIR and XRD analyses showed the presence of molecular interactions and chemical linkages between nHAp particles, titania and gelatin matrix. The compressive strength of titania reinforced nanocomposites scaffolds could be elevated up to 10.15 MPa while those of nHAp/gelatin were 4.87 MPa. These results show that newly developed nHAp/TiO₂/gelatin composites may be superior for bone tissue engineering.     

Anticorrosion potential of domperidone on copper in different concentration of hydrochloric acid solution

The inhibition performance of domperidone on the corrosion of copper in different concentration of HCl solution has been investigated by electrochemical, weight loss, and surface analysis, and theoretical calculation methods. Results indicate that domperidone was found to be an effective inhibitor with the inhibition efficiency as high as 98.5% when the HCl concentration was 0.01 M, and the corrosion rate of copper increased with the increment of HCl concentration from 0.001 to 1 M. The potentiodynamic polarization results revealed that domperidone can be seen as a mixed type inhibitor when the HCl concentration was high (1 and 0.1 M), while it acted as a cathodic inhibitor for copper at low HCl concentrations (0.01 and 0.001 M). The potentiodynamic polarization results revealed that domperidone can be seen as mixed-type or cathodic inhibitor as the HCl concentration changes. Scanning electron microscopy studies indicated the formation of protective films of inhibitor molecule on copper surface. Besides, density functional theory-based quantum chemical calculations and molecular dynamics simulations showed the electronic structure of domperidone and its optimized adsorption configuration on copper surface, which could account for the experimental findings.     

Sodium doped-V2O5 nanorods for visible light irradiated photocatalytic performance for the degradation of Rh-dye

The sodium doped vanadium pentaoxide (Na.V₂O₅) nanorods were synthesized through hydrothermal method. The sodium (Na) enriched V₂O₅ nanorods with different concentration of Na varied from 1 wt%, 3 wt% and 5 wt%. X-ray diffraction, field emission scanning electron microscopy, UV–Visible spectroscopy and fourier transform infrared spectroscopy were used to investigate the structural, morphological and optical properties of the synthesized pure V₂O₅ and Na-doped V₂O₅ (1, 3 and 5 wt%). The microstructural studies confirmed the formation of nanorods structure for Na doped V₂O₅. The photocatalytic performance of these synthesized photocatalysts were studied to degrade Rhodamine B dye in visible light region. Their efficiency to perform the photodegradation was improved in all Na doped V₂O₅ samples (1, 3 and 5 wt%) than that of pure V₂O₅ nanorods. Among all concentration of Na in V₂O₅ nanorods, the Na.V₂O₅ (5 wt%) exhibited the maximum degradation of the rhodamine dye having 88.9% degradation with rate constant 0.0619 min^?1 of a reaction.     

Effect of demineralization process on the liquefaction of Turkish coals in tetralin with microwave energy: Determination of particle size distribution and surface area

The effects of solvent/coal (S/C) ratio and demineralization on the solubilization of Turkish coals (Tunçbilek, Muğla-Yatağan, Beypazarı lignites and Zonguldak bituminous coal) in tetralin by microwave energy have been investigated. Particle size distributions and the surface area of the coals decreased with demineralization. For the investigation of the effect of the S/C ratios with values of 8/1, 10/1 and 12/1, the coal samples were heated by microwave energy for 20 min. The result indicated that the optimum S/C ratio was 8/1. The effect of microwave heating period was investigated at this value and the heating period was changed from 5 to 20 min at 5-min intervals. It was found that THF solubles yields of original coals were higher than those for demineralized coal except for Muğla-Yatağan lignite.     

Biophysical studies on bone cement composites based on polyester fumarate

In this study poly(vinlyl chloride) (PVC) was modified by using ethylenediamine, diethylenetriamine, and ethanolamine as a crosslinker in dimethylformamide. Reaction variables were optimized for getting desired crosslinked PVC, which was further reacted with maleic anhydride to form graft polymer. The anhydride group on further hydrolysis gives carboxylic group, which can exchange proton with other cations.The polymers were characterized by FTIR spectroscopy and thermal analysis (TGA/DTA). Swelling behavior was examined in various electrolytic solutions. Modified PVC have shown good thermal stabilities and absorption capacities in neutral and acidic media, due to which these polymers might find applications in cation exchanger resin and chromatography. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

添加剂对铸造焦性能的影响

以山西柳林和沁源煤为主配料,选用５种炭质添加剂进行子多个配料方案的炼焦试验,通过焦炭光学组织的定量分析和气孔结构的研究,解释了不同添加剂配入量对铸型造焦性能的影响。     

盐酸尾气治理方法

介绍了盐酸储槽中盐酸挥发的氯化氢气体及生产盐酸时的氯化氢气体的治理方法。     

盐酸生产工艺改进

对盐酸生产工艺进行改造,解决了大气污染和酸性下水污染问题.     

盐酸装置改造总结

针对原二合一下点火式石墨盐酸合成炉存在的生产能力低、工艺集成度不高、手动控制、安全性不高等问题,浙江善高化学有限公司与其他公司合作开发了四合一盐酸合成炉,总结了其特点和考核情况。     

Photocatalytic intrinsic reaction kinetics. II: Effects of oxygen concentration on the kinetics of the photocatalytic degradation of dichloroacetic acid

The effect of oxygen on the reaction kinetics of the photocatalytic oxidation of dichloroacetic acid at pH below the titanium dioxide isoelectric point (pH from 5 to 4) was studied. A kinetic scheme based on the direct hole attack to the dichloracetate ion in conjunction with the classical role of oxygen acting as an electron acceptor is proposed. Oxygen also intervenes in a direct addition reaction to one of the intermediate reaction products. Experiments were conducted in a well-mixed, small, flat plate reactor employing Aldrich titanium dioxide as the photocatalyst in the suspension mode and using polychromatic irradiation with energy in the range from 275 to 385 nm in wavelength. A complete mathematical model, including the effect of the absorbed radiation intensities and catalyst concentration was developed. Experimental data agree well with theoretical predictions employing just two kinetic parameters derived from the proposed reaction mechanism.     

A kinetic study on the devolatilisation of animal derived byproducts

The thermal degradation characteristics and chemical kinetics of meat and bone meals (MBM) during the volatiles release stage are investigated by thermogravimetry. In addition to the characterization of the animal by-product, a TA Q600 thermogravimetric analyser was used to evaluate the devolatilisation behaviour and determine the kinetic parameters over the temperature range of 30–1000 °C. Non-isothermal pyrolysis tests were conducted at ambient pressure, for four heating rates (5, 20, 50 and 100 °C/min), and particle sizes being between 150–250 μm. The independent parallel, first order, reactions model was used for the simulation of the pyrolysis data, while the effect of mineral matter presence on kinetic constants was evaluated. MBM decomposition presented two distinct weight loss steps and increased conversion rates were attained at higher heating regimes. The model elaborated to describe the thermal devolatilisation of MBM considers four fractions decomposing simultaneously. Accurate predictions of experimental data were achieved in all test cases. Demineralisation resulted in enhanced kinetic constants for the pseudo-reactions at the lower temperature regions.     

Influence of feedstock concentration on tetragonality and particle size of hydrothermally synthesized barium titanate powders

Barium titanate (BaTiO₃) powders were synthesized through hydrothermal process with Ba(OH)₂·8H₂O and TiO₂. By increasing the feedstock concentration (FC) from 0.25 to 1.50 M, BaTiO₃ powders maintain a stable average particle size (~180 nm and ~6.4441 m²/g) with an increasing tetragonality (c/a: 1.0065–1.0075). Johnson-Mehl-Avrami and standard reaction rate equations were adopted to analyze the kinetic process of BaTiO₃ formation. The reaction is governed by first-order and phase-boundary-controlled mechanism for 0.25 M and 1.50 M, respectively. Lower extent of reaction is believed to lead to the better tetragonality for BaTiO₃ powders fabricated with higher FC. On the other hand, the relative stable particle size is correlated with the unvaried nucleation frequency and grain growth rate with various FC. This work can provide a guideline to manipulate the properties of BaTiO₃ powders used in electronic industry.