Numerical investigation of grooves effects on the thermal performance of helically grooved shell and coil tube heat exchanger

Heat exchangers are integral parts of important industrial units such as petrochemicals, medicine and power plants. Due to the importance of systems energy consumption, different modifications have been applied on heat exchangers in terms of size and structure. In this study, a novel heat exchanger with helically grooved annulus shell and helically coiled tube was investigated by numerical simulation. Helically grooves with the same pitch of the helical coil tube and different depth are created on the inner and outer wall of annulus shell to improve the thermal performance of heat exchanger. In the first section, thermal performance of the shell and coil heat exchanger with the helical grooves on its outer shell wall was compared with same but without helical grooves. At the second section, helically grooves created on both outer and inner wall of the annulus shell with different groove depths. The results showed that the heat exchanger with grooves on both inner and outer shell wall has better thermal performance up to 20% compared to the heat exchanger with grooves on only outer shell wall. The highest thermal performance achieves at lower flow rates and higher groove depths whereas the pressure drop did not increase significantly.     

新抗冲型ACR的合成与研究

采用种子乳液聚合法制备了含有PBA／PMMA＼PS三种组分的丙烯酸醋类抗冲型改性剂ACR，在ACR的幔层结构中引入接枝剂甲基丙烯酸烯丙酯（AIMA）来完善幔层结构，从而实现核一壳之间良好的结合，用红外光谱（FTIR）和差示扫描量热法（DSC）对ACR的组成和结构进行表征。研究结果表明：由PBA＼PMMA＼PS三组分构成的ACR在抗冲击性能上要略优于由简单的PBA＼PMMA构成的ACR，苯乙烯单体（St）最多可以取代大约1／3壳层的甲基丙烯酸甲酯（MMA），甲基丙烯酸烯丙酯（AIMA）的引入对幔层结构的完善起了显著的作用。     

新型CO耐硫变换催化剂QDB-04的开发及应用

介绍了新型CO耐硫变换催化剂QDB-04的性能特点及工业应用情况，对Shell粉煤气化煤气第一变换炉反应深度的问题及控制第一变换炉“床层飞温”的办法进行了讨论，提出了ODB-04催化剂应用于低水气比Shell粉煤气化制氨变换工艺的设计方案。     

壳牌煤气化装置洗涤塔出口合成气带水原因分析及对策

介绍了壳牌粉煤气化装置中洗涤塔工艺流程;分析了洗涤塔内部结构;阐述了洗涤塔出口合成气带水的现象及危害;找出了引起洗涤塔工艺气带水的原因;采取了相应的技改措施。结果表明,通过调整工况,消除了带液现象。     

熔模铸造型壳废弃物组成及其再利用分析

分别分析了最常用的水玻璃型壳和硅溶胶型壳在脱蜡后的型壳，焙烧后的型壳和浇注后清理的型壳废弃物的物相组成，即水玻璃型壳的主要物相是石英或Al-Si系材料物相；硅溶胶型壳的主要物相是Al-Si系材料物相。并依此提出了型壳废弃物资源化利用的一些途径：①作建筑材料，如水泥、沙料、砖、填料；②作熔模铸造的原材料，如耐火粉料和砂料、粘接剂、硬化剂。     

Antioxidants and antiradicals in almond hull and shell (Amygdalus communis L.) as a function of genotype

To compare the antioxidant and antiradical activity of Amygdalus communis L. hulls and shells phenolic extracts in different genotypes, 18 A. communis L. genotypes were selected from those in Qooshchi, Qalgachi, Qovarchin Qale, Najaf Abad, Jamal Abad, Kahriz, Sfahlan of West and East Azerbayjan provinces of Iran in 2007. The fruits of these almonds were collected, their hulls and shells dried, ground and then methanolic extracts prepared from these hulls and shells. Total phenolic content was determined using the Folin–Ciocalteu (F–C) method. The extracts’ reducing power and scavenging capacity for radical nitrite, hydrogen peroxide and superoxide were evaluated. Significant differences were found in phenolic content of hulls and shells among various genotypes, radical scavenging capacity percentage varied significantly among genotypes and their hulls and shells. S₃-7 genotype with the highest phenolic content and antioxidant activity in its hulls represents a valuable genotype for procuring antioxidant phenolic compounds.     

我国煤气化技术的特点及应用

介绍了我国煤气化技术的发展现状;论述了固定床间歇气化技术、恩德炉粉煤流化床气化技术、灰熔聚煤气化技术、壳牌煤气化技术、德士古水煤浆加压气化技术、四喷嘴对置式水煤浆气化技术等煤气化技术的工艺特点、技术优势和不足;针对煤气化技术的选择提出了相关注意事项。     

Platinum Nanoparticles Anchored on TiO2/C Nanowires as a High Performance Catalyst for Hydrogen Peroxide Eletroreduction

In this paper, we employed the as‐prepared TiO₂/C core/shell nanoarrays (TiO₂/C) obtained by a facile thermal evaporation method as a three‐dimensional (3D) architecture to support Pt nanoparticles through an optimized electrodeposition process. The morphology and structure of the as‐prepared electrode are characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Its catalytic performance towards H₂O₂ electroreduction in basic medium is evaluated by linear sweep voltammetry (LSV) and chronoamperometry (CV). Results revealed that the electrode exhibits significantly high catalytic activity. The current density reached –0.172 A cm⁻² in 1 mol dm⁻³ NaOH and 0.5 mol dm⁻³ H₂O₂ at –1.1 V (vs. Ag/AgCl). This high performance might be due to the 3D electrode architecture inheriting the high electronic conductivity from carbon shell and providing a short pathway for the ion diffusion, and the using of Pt owning an excellent catalytic activity.     

Total carotenoid differences in scallop tissues of Chlamys nobilis (Bivalve: Pectinidae) with regard to gender and shell colour

The aim of this study was to investigate whether total carotenoid content (TCC) in noble scallop Chlamys nobilis is related to body tissue, shell colour, and gender. TCC was determined by a UV–vis recording spectrophotometer in tissue of gonad, adductor, mantle, and gill separately sampled from male and female individuals with orange and brown shell colours from the same cultured population. TCC was significantly different among body tissues, depending on shell colour and gender, ranging from 0.73 to 59.85 μg g⁻¹. In general, TCC was greater in the order of gonad > mantle > adductor > gill. In the same gender, orange shell colour individuals contained significantly higher TCC than brown ones in all four tissues (P < 0.05). In the same shell colour, female contained significantly higher TCC than male in gonad and adductor tissues (P < 0.05).     

On the asymptotic behaviour of shells of revolution in free vibration

We consider the free vibration problem of thin shells of revolution of constant type of geometry, focusing on the asymptotic behaviour of the lowest eigenfrequency, as the thickness tends to zero. Numerical experiments are computed using two discretization methods, collocation and finite elements, each corresponding to a different shell model. Our results are in agreement with theoretical results obtained using interpolation theory and cited in literature.