Effects of stearic acid coated talc,CaCO3, and mixed talc/CaCO3 particles on the rheological properties of polypropylene compounds

The effect of the stearic acid coated fillers and their geometry on the shear/dynamic viscosity and complex viscosity has been investigated using polypropylene (PP) compounds filled with stearic acid uncoated and coated talc, calcite, and mixed talc/calcite particles. The viscosity was measured over a wide range of shear rates (10^?8 to 10³) using a capillary, cone‐plate and sandwich rheometer. Overall, the rheological properties of the compounds exhibited different behavior upon different filler systems, stearic acid involvement, shear stress or strain, and frequencies due to stearic acid involvement. This implies that the stearic acid lowers the interfacial force between the filler surface and the resin matrix, followed by a favorable processing. In addition, at very low shear stresses, the viscosity of talc(un) compounds was higher than calcite(un) ones; at very high shear stresses, on the other hand, talc compounds became lower than calcite(un) compounds. This is interpreted as due to the different geometry between talc and calcite. The yield value as a function of shear stress was observed for all filler systems and exhibited lower than that obtained from the extrapolation. Furthermore, the Cox–Merz relation between the complex and shear viscosity for both the stearic acid uncoated and coated compounds is found not valid. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2105–2113, 2004     

Effects of gypsum on growth and mineral content of Brussels sprouts,and soil properties of Orthic Podzols

Studies of crop response to Ca fertilizers are generally few as well as information concerning the Ca nutrition of Brussels sprouts (Brassica oleracea var.gemmifera). Six field studies were conducted, over three years, to determine yield response of Brussels sprouts to soil applied gypsum (CaSO₄.2H₂O), lime (calcite), and elemental S on sandy loam to loamy sand Orthic Podzols in Prince Edward Island. Relative yield of marketable (0–32mm) Brussels sprouts were related to soil ammonium acetate extractable Ca (r = 0.71). The highest yields (11 to 13 t ha^–1) were associated with an extractable Ca of above 400µg g^–1 soil, while a Ca level below 400µg reduced yield by 20%. Highest marketable yields were associated with a Ca level in the leaf tissue (in upper mature leaves at sprout formation) of above 2.2% (w/w) (r = 0.55), this in turn was associated (r = 0.87) with an extractable soil Ca above 400µg g^–1 soil. Calcite and elemental S did not influence yield or mineral content. Gypsum, as expected increased leaf S content, but leaf tissue S levels were not related to marketable yield. Slight decreases in soil pH due to increasing gypsum rate (0.5–4.3 t ha^–1) were associated with changing accumulations of B, Mn, Fe, Ca, and Zn in the leaf tissue. Gypsum had little effect on soil porosity and structure indices, but changing pH (in both gypsum and lime treatments) significantly influenced soil microbial biomass.     

L-苯丙氨酸为模板碳酸钙纳米晶体的生长

用L-苯丙氨酸为模板,氯化钙和碳酸钠反应而制备碳酸钙纳米晶体,采用红外光谱和粉末X-射线衍射方法对其进行表征,通过扫描电镜观察纳米晶体的形貌,研究反应温度和L-苯丙氨酸浓度对碳酸钙纳米晶体的晶型和形貌的影响。研究表明:随着温度和L-苯丙氨酸浓度的升高,高能量晶型的含量增加,说明升温和增加L-苯丙氨酸浓度能够促进稳定碳酸钙晶型的生长。     

大理石、萤石对不锈钢焊条熔滴过渡及熔滴中夹杂物的影响

采用水中收集熔滴、光学显微分析、电子扫描能谱分析、计算机图像分析及平板堆焊等试验方法，分别研究了大理石、萤石对不锈钢焊条熔熵过渡行为，以及它们对熔滴中非金属夹杂物及焊缝中气孔的影响。结果表明焊缝和熔滴中的非金属夹杂物呈圆球形，它们是熔滴反应区化学反应的产物，属“内生”性质；药皮中大理石含量增大时，熔滴尺寸与熔滴中夹杂物含量的波动变化存在对应关系，焊条工艺性变差，焊缝中气孔敏感性未减小；药皮中氟化稀土和萤石比值增大，熔滴细化，熔滴中夹杂物含量增大，焊条工艺性能有所改善，焊缝中气孔倾向未减小。     

钙质胶结砂岩特征、分布及其对储层的影响

结合野外露头、岩心、薄片观察、元素扫描等资料，探讨了钙质胶结物在鄂尔多斯盆地中西部延长组下组合砂岩中的主要特征、分布规律及其对储层品质的影响。结果显示，下组合广泛发育钙质胶结砂岩，宏观上呈条带状近平行地层产状发育、层内不规则及与裂缝伴生3种发育形式，纵向上可分为薄层砂体全胶结型、厚层砂体顶底胶结型、砂体内分散胶结型及砂层内部韵律式胶结型4种，着重分析了韵律式钙质胶结的成因。钙质胶结物主要为方解石，含量为20%~40%；可分为3期:早期泥微晶状方解石；中期亮晶状嵌晶式方解石胶结、晚期亮晶状方解石充填小孔隙。钙离子来自泥岩或裂缝。钙质胶结物主要形成于成岩早期阶段，降低了储层物性，多形成干层，同时加剧了储层非均质性。     

Influence of the aggregate quality on the physical properties of natural feebly-hydraulic lime mortars

This paper examines the influence of the shape, average size and calcite content of the aggregate on strength, porosity, water absorption, density and capillary suction of natural feebly-hydraulic lime (NHL 2) mortars. Four types of aggregate were analysed in order to determine calcite content, particle shape and average particle size. Four different mortar mixes were then designed and produced using each of the aggregate types and NHL 2 as a binder. The mixing and curing as well as the aggregate:binder proportions were kept constant in order to attribute variation of mortar properties to the quality of the aggregate. The results suggest that an increase in the aggregate’s calcite content lowers the flexural and compressive strength of the mortar. This study also determined that sharp aggregate as well as aggregate with a small average particle size tends to increase the mechanical strength and bulk density of a mortar simultaneously reducing porosity, water absorption and capillary suction. Furthermore, this paper concludes that aggregates containing particles of a wide size range will also increase the mechanical strength and bulk density of the hardened mortar diminishing porosity, water absorption and capillary suction.      

改进邻菲罗啉比色法测定低铁石灰石（方解石）、白云石中三氧化二铁含量

低铁含量的石灰石(方解石)和白云石是生产光伏玻璃的主要原料,而邻菲罗啉比色法是一种高效准确的铁含量检测方法。但是,国家标准GB/T 3286.4—2012中规定的测定范围远远超出实际生产要求,因此直接应用国标会产生较大的实验误差。本文通过调节实验中的样品质量和混合熔剂质量,在国标规定方法的基础上进行改进。实验结果表明,增大样品质量和混合熔剂质量分别至2.00g和8.0g时,实验准确度得到了极大提升,结果符合国家标准允许差。     

樟叶提取物作为新型环境友好抑制剂在白钨矿与方解石浮选分离中的应用（英文）

采用简单的物理方法,直接榨取樟叶汁液作为白钨矿和方解石分离的抑制剂。通过接触角测量、傅里叶转换红外光谱测试和原子力显微镜研究樟叶提取物中活性成分及其抑制机理。浮选试验表明,樟叶提取物对方解石有较强的抑制作用,对白钨矿的抑制作用较小。原子力显微镜检测证实方解石表面吸附有樟叶提取物的有效成分。红外光谱结果表明,吸附在方解石表面的组分含有大量的羟基,这些羟基使方解石疏水。Zeta电位和红外光谱结果表明,樟树叶提取物在方解石表面的吸附量远大于在白钨矿表面的吸附量。樟叶提取物在白钨矿和方解石浮选分离中具有潜在的应用价值。     

The phenol steam reforming reaction towards H2 production on natural calcite

The steam reforming of phenol towards H₂ production was studied in the 650–800 °C range over a natural pre-calcined (air, 850 °C) calcite material. The effects of reaction temperature, water, hydrogen, and carbon dioxide feed concentrations, and gas hourly space velocity (GHSV, h⁻¹) were investigated. The increase of reaction temperature in the 650–800 °C range and water feed concentration in the 40–50 vol% range were found to be beneficial for catalyst activity and H₂-yield. A similar result was also obtained in the case of decreasing the GHSV from 85,000 to 30,000 h⁻¹. The effect of concentration of carbon dioxide and hydrogen in the phenol/water feed stream was found to significantly decrease the rate of phenol steam reforming reaction. The latter was probed to be related to the reduction in the rate of water dissociation as evidenced by the significant decrease in the concentration of adsorbed bicarbonate and OH species on the surface of CaO according to in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS)-CO₂ adsorption experiments in the presence of water and hydrogen in the feed stream. Details of the CO₂ adsorption on the CaO surface at different reaction temperatures and gas atmospheres using in situ DRIFTS and transient isothermal adsorption experiments with mass spectrometry were obtained. Bridged, bicarbonate and unidentate carbonate species were formed under CO₂/H₂O/He gas mixtures at 600 °C with the latter being the most populated. A substantial decrease in the surface concentration of bicarbonate and OH species was observed when the CaO surface was exposed to CO₂/H₂O/H₂/He gas mixtures at 600 °C, result that probes for the inhibiting effect of H₂ on the phenol steam reforming activity. Phenol steam reforming reaction followed by isothermal oxygen titration allowed the measurement of accumulated “carbonaceous” species formed during phenol steam reforming as a function of reaction temperature and short time on stream. An increase in the amount of “carbonaceous” species with reaction time (650–800 °C range) was evidenced, in particular at 800 °C (4.7 vs. 6.7 mg C/g solid after 5 and 20 min on stream, respectively).