Effect of carbohydrates on arterial pressure. An experimental study]

The effect of incorporation of sugar in a diet on a level of arterial pressure in 120 rats Wistar was examined. The replacement of 50% of starch by sugar in the balanced diet with a normal content of protein and white salt did not have a profound influence on a pressor effect. However on a background of an abundant content of white salt in a diet protein and fat balanced, the incorporation of sugar in a diet resulted in additional increase of arterial pressure (+27.27 mm of a hg) in comparison with a saline diet without sugar (p < 0.001). The sugary diet with normal content of white salt bring to evident pressor effect (+6.60 mm of a hg) at deficiency of protein (p < 0.001), though on others variants of protein deficiency diets the slight tendency to a drop of arterial pressure was observed. The causes of ambiguous changes of arterial pressure in a protein deficiency remain unclear.     

TEM study of PM2.5 emitted from coal and tire combustion in a thermal power station

The research presented here was conducted within the scope of an experiment investigating technical feasibility and environmental impacts of tire combustion in a coal-fired power station. Previous work has shown that combustion of a coal+tire blend rather than pure coal increased bulk emissions of various elements (e.g., Zn, As, Sb, Pb). The aim of this study is to characterize the chemical and structural properties of emitted single particles with dimensions <2.5 microm (PM2.5). This transmission electron microscope (TEM)-based study revealed that, in addition to phases typical of coal fly ash (e.g., aluminum-silicate glass, mullite), the emitted PM2.5 contains amorphous selenium particles and three types of crystalline metal sulfates never reported before from stack emissions. Anglesite, PbSO4, is ubiquitous in the PM2.5 derived from both fuels and contains nearly all Pb present in the PM. Gunningite, ZnSO4-H2O, is the main host for Zn and only occurs in the PM derived from the coal+tire blend, whereas yavapaiite, KFe3+(SO4)2, is present only when pure coal was combusted. We conclude that these metal sulfates precipitated from the flue gas, may be globally abundant aerosols, and have, through hydration or dissolution, a major environmental and health impact.     

Feasibility study for the development of certified reference materials for specific migration testing. Part 2: estimation of diffusion parameters and comparison of experimental and predicted data.

This paper describes the second part of a project whose main objective was to develop the know-how to produce certified reference materials (CRMs) for specific migration testing. Certification parameters discussed are the diffusion coefficient, D(P), the respective polymer-specific coefficient, A(P), of the migrant polymer combinations and the partitioning coefficient, K(P,F), describing the partitioning of the migrant between the polymer and a food simulant. The parameters were determined for 16 preliminary candidate CRMs. Each parameter was determined by one laboratory. The six materials most suitable as reference materials were selected and the parameters then determined by four laboratories. The coefficients resulting from this small-scale interlaboratory comparison study can be regarded as the most reliable values available to date. These coefficients were applied for a comparison of experimental and predicted migration data. The experimental migration data arose from the same project and were determined by one laboratory for the first 16 materials and subsequently by four laboratories for the six materials selected in the second phase. Overall, experimental and predicted migration data fit together quite well. Roughly half of the predicted data were within +/-10%; almost all predicted data were within +/-40% compared with the experimental data.     

An experimental study of twin-screw extrusion-cooking of maize grits

The use of a twin-screw extrusion-cooker to process maize grits is described. The expansion, bulk density, colour and aqueous dispersion rheology have been related to the extrusion cooking variables: screw speed, feed rate, moisture content and barrel zone temperature. A pseudo-viscosity quantity has been defined to describe the extrudate viscosity at the die which was also related to the extrusion-cooking variables. The pressure and temperature profiles in the extruder were recorded together with the mechanical and thermal energy consumption as a function of the extrusion-cooking variables. These experiments with a highly instrumented cooking-extruder indicate the condition of the material in the barrel prior to formation of the product.     

An experimental study of shape stability in glued boards

An experimental study of shape stability in wooden glued boards was performed to verify certain results of particular interest obtained earlier in numerical simulations. Possibilities for achieving products of good shape stability by gluing boards together in an optimal way are discussed. Since twist is often the most serious form of distortion defects for the user, it was the main type of board deformation considered. Three types of glued products were tested. The experiments show clearly that glued boards can be produced that remain stable in shape when exposed to extreme variations in moisture. The results agree well with the numerical simulations performed earlier. It was found that initial twist could be reduced by proper application of pressure during gluing and that through gluing the occurrence of cracking defects on visible surfaces could be substantially reduced.     

高温滤料用纤维燃烧气体释放的测试研究

燃烧气体是评价耐高温纤维阻燃性能指标之一,通过设计燃烧试验装置对四种袋式除尘器常用高温滤料纤维(聚苯硫醚纤维、间位芳纶、聚酰亚胺纤维和芳砜纶)进行高温燃烧,利用烟气分析仪器测定其燃烧产生的气体成分及其含量。结果显示,燃烧气体成分与纤维的化学结构和燃烧温度有关。CO是四种纤维的主要燃烧产物,其浓度随温度的变化曲线近似于抛物线;含有酰胺基的纤维燃烧气体中含有NOx,其浓度随温度呈阶梯状变化;芳砜纶和聚苯硫醚纤维燃烧气体中含有SO2,其浓度随温度呈波浪状变化。     

激光焊接金刚石工具过渡层预合金粉末的试验研究

目前可以用于制备激光焊接金刚石工具过渡层粉末的方法主要有机械混合法、雾化法和化学共沉淀法。化学共沉淀法生产的粉末成分均匀,实现了粉末的预合金化,并且设备简单,生产成本低。此次试验采用草酸盐化学共沉淀法,成功制备了3种不同成分的激光焊接金刚石工具过渡层预合金粉末。焊接强度测试表明,3种粉末的焊接强度均满足欧盟EN13236安全标准,其中2#粉末的焊缝强度最高。X射线物相分析结果表明,3种粉末的主相都是Co3Fe7和CoFe。此外,固定Fe与Co的质量比,加入2wt.%的铜可以有效提高预合金粉末过渡层的焊接强度和稳定性。这是因为,Cu原子完全溶入到Co3Fe7或CoFe晶胞中并形成固溶体,产生了固溶强化。     

小■浸渍工艺的实验探究

针对常规浸渍方法采用绞装丝浸渍的生产方式存在重复用工和重复干燥,效率低、能源消耗大等问题。采用在小■真空给湿时加入绞装丝浸渍助剂EKL-101,研究小■生丝浸渍工艺。通过将绸厂中的生丝浸渍和干燥工序合并到生丝生产过程中的真空渗透工序,以期达到减少绸厂生产加工工序、减少用工、提高劳动生产率、节省能耗的目的。研究结果表明:小■生丝浸渍前,将小丝片置于40～50℃下,平衡干燥180 min,小■丝片回潮率控制在8%以下;当助剂质量分数为1.0%时,浸渍温度40～45℃,相对真空度-0.08 MPa,浸渍时间60～120 min,可以得到与传统生丝浸渍基本相同的效果。     

竹原纤维性能研究及其毛巾产品的开发

介绍了竹原纤维的性能及其家用产品开发,阐述了竹原纤维纺纱、织造与染整等各工序的生产工艺及注意事项.开发的毛巾产品手感柔软,染色性好,有特有的抗菌功能.     

苇浆H2O2强化两段氧脱木素的研究与生产实践

对洗筛后未漂细浆进行了H2O2强化氧脱木素研究,并对脱木素浆采用XH工艺漂白。研究和生产实践均表明：在氧脱木素过程添加1.0%～1.5%过氧化氢,可以有效降低氧脱后纸浆硬度,同时提高纸浆白度;脱木素浆再经XH漂白后,漂白浆白度可达到81%ISO以上。     

Performance of a sequential reactive barrier for bioremediation of coal tar contaminated groundwater

Following a thorough site investigation, a biological Sequential Reactive Barrier (SEREBAR), designed to remove Polycyclic Aromatic Hydrocarbons (PAHs) and BTEX compounds, was installed at a Former Manufactured Gas Plant (FMGP) site. The novel design of the barrier comprises, in series, an interceptor and six reactive chambers. The first four chambers (2 nonaerated-2 aerated) were filled with sand to encourage microbial colonization. Sorbant Granular Activated Carbon (GAC) was present in the final two chambers in order to remove any recalcitrant compounds. The SEREBAR has been in continuous operation for 2 years at different operational flow rates (ranging from 320 L/d to 4000 L/d, with corresponding residence times in each chamber of 19 days and 1.5 days, respectively). Under low flow rate conditions (320-520 L/d) the majority of contaminant removal (>93%) occurred biotically within the interceptor and the aerated chambers. Under high flow rates (1000-4000 L/d) and following the installation of a new interceptor to prevent passive aeration, the majority of contaminant removal (>80%) again occurred biotically within the aerated chambers. The sorption zone (GAC) proved to be an effective polishing step, removing any remaining contaminants to acceptable concentrations before discharge down-gradient of the SEREBAR (overall removals >95%).     

An experimental and numerical study of shape stability in laminated timber columns

The study concerns the question of how the shape stability features of laminated columns of Norway spruce can be improved in terms of twist through optimal orientation of the individual laminates. Both experimental testing and numerical simulations were employed for evaluating twist stability. In all the columns studied, deformations were measured experimentally at different moisture content levels. A number of columns were also selected for numerical analysis in order to obtain a more thorough understanding of the twist behavior involved, their geometries and material properties of interest being determined. The experimental results showed the twist stability of the columns to be highly dependant upon the internal orientation of the individual laminates. It was also found that high quality columns in terms of shape stability could be manufactured, even when the center-core material has a strong twist tendency. The numerical simulations performed were in close agreement with the experimental results.     

内燃机用空气过滤纸的阻燃性研究

为了提高内燃机用空气过滤纸的阻燃性能,实验探讨了聚磷酸铵阻燃剂、溴-锑协同阻燃剂以及二者的复配阻燃剂分别在不同留着率条件下对空气过滤纸的阻燃效果、力学性能以及透气性的影响。结果显示：复配阻燃剂在留着率为20%,且聚磷酸铵阻燃剂与溴-锑协同阻燃剂留着率之比为1∶1时,滤纸的阻燃性能满足GB/T14656-93的要求且无烟,此时挺度基本不变,耐破度下降约12%,透气率下降约13%。