CFD design and simulation of ethylene dichloride (EDC) thermal cracking reactor

At high temperature, ethylene dichloride decomposes into vinyl chloride monomer and HCl by a complex reaction mechanism. Due to chemical reaction type and heat transfer mechanism, design and simulation of cracking reactors are complicated. This process is very important from either chemical reaction or transport phenomena’s point of view. In this study, 2D simulation of cracking reactor is performed with FLUENT software. Simulation results were compared with the experimental data. Then, we investigate the simulation results and effect of various parameters on the process. Results show that with process progress and temperature increase during reactor length, conversion and coke formation amount are increased. At the end of the process, conversion is 52.69 that has good agreement with industrial data. Addition of promoter to the process fluid and fluid behavior in different coil outlet temperatures was studied; finally, the effects of these factors are described in detail.     

Alcalase-generated proteolysates of stone fish (Actinopyga lecanora) flesh as a new source of antioxidant peptides

In the present study, the alcalase-generated proteolysates obtained after 8 h of proteolysis of stone fish flesh showed the most potent antioxidant activity in terms of DPPH^? radical scavenging activity (77.43%, IC₅₀ of 0.5 mg/mL), ABTS^? radical scavenging activity (92.73%, IC₅₀ of 0.33 mg/mL) and FRAP value (39.2 mmol/100 mL FeSO₄). These proteolysates profiled and characterized as antioxidative peptides. The proteolysates were initially subjected to ultrafiltration using MWCO Spin-X UF. Potent fractions were further characterized based on hydrophobicity using reversed-phase high-performance liquid chromatography (RP-HPLC) and isoelectric point using an OFFGEL isoelectric focusing fractionator. Results indicated that most of the antioxidative peptides found in fractions with a molecular weight (MW) of less than 2 kDa, hydrophilic (hydrophilicity >80%) and basic (pI = 9.7). The final purified fraction with the highest antioxidant activity was selected for peptide identification and sequencing using Q-TOF mass spectrometry. A total of four peptides were identified, from which Peptide 1 (GVSGLHID) showed the highest antioxidant activity and this has potential as a novel bioingredient of nutraceuticals and functional foods to promote human health.     

Following ergonomics guidelines decreases physical and cardiovascular workload during cleaning tasks

The aim was to investigate the effect of ergonomics guidelines on muscular activity, postural and cardiovascular load during cleaning. Eighteen cleaners performed 10 min of cleaning tasks in two locations; three min in a laboratory and seven min in a lecture room. All participants performed the task with or without focusing on ergonomics guidelines (ergonomics/non-ergonomics session). Bipolar surface electromyography was recorded bilaterally from upper trapezius and erector spinae muscles. A tri-axial accelerometer package was mounted on the low back (L5-S1) to measure postural changes, and the cardiovascular load was estimated by electrocardiogram. Ergonomics sessions resulted in lower muscular load, a more complex pattern of muscular activity, lower range of motion and angular velocity of the trunk as well as lower cardiovascular load compared with non-ergonomics sessions (p < 0.05). The study highlighted the multiple musculoskeletal and cardiovascular benefits of following ergonomics guidelines during cleaning tasks. PRACTITIONER SUMMARY: This study investigated the effects of following instructive ergonomics guidelines during cleaning tasks (daily curriculum of cleaning including mopping, sweeping, changing trash bins and cleaning of desks and blackboards). Following the ergonomics guidelines reduces the general workload and induces a more complex pattern of muscular activity. The study contributes with novel knowledge concerning ergonomics guidelines and work techniques.     

Application of partial least squares and radial basis function neural networks in multivariate imaging analysis-quantitative structure activity relationship: study of cyclin dependent kinase 4 inhibitors

The detailed application of multivariate image analysis (MIA) method for the evaluation of quantitative structure activity relationship (QSAR) of some cyclin dependent kinase 4 inhibitors is demonstrated. MIA is a type of data mining methods that is based on data sets obtained from 2D images. The purpose of this study is to construct a relationship between pixels of images of investigated compounds as independent and their bioactivities as a dependent variable. Partial least square (PLS) and principal components-radial basis function neural networks (PC-RBFNNs) were developed to obtain a statistical explanation of the activity of the molecules. The performance of developed models were tested by several validation methods such as external and internal tests and also criteria recommended by Tropsha and Roy. The resulted PLS model had a high statistical quality (R2 = 0.991 and R2(CV) = 0.993) for predicting the activity of the compounds. Because of high correlation between values of predicted and experimental activities, MIA-QSAR proved to be a highly predictive approach.     

Unconfined compressive strength of loose sandy soils grouted with zeolite and cement

Cement production requires a lot of energy and is also one of the most important sources of carbon dioxide emissions. Consequently, the replacement of part of the cement with a more environmentally friendly material, such as zeolite, is of great importance. The present research involves the conducting of a series of laboratory tests on loose sand specimens ($D_r\approx 30\%$) grouted with cementitious materials (cement and zeolite) to investigate the effect of different parameters, such as the size of the sand particles, the ratio of water to cementitious materials (W/CM) and the replacement of a certain percentage of the cement in the grout with zeolite (Z), on the unconfined compressive strength (UCS) of the grouted sand specimens. The results indicate that for all the grout W/CM and sand grain sizes, when Z is increased from zero zeolite (Z₀), the UCS initially increases. Then, after reaching an optimal amount (Z₃₀), it decreases. Moreover, increasing both the size of the sand particles and the W/CM of the grout is seen to reduce the UCS of the grouted specimens. The UCS of the grouted sand specimens increases with the equilibrium of SiO₂ and Al₂O₃ with CaO elements in the grouting suspension. Finally, equations with a high performance are proposed to predict the UCS of sands grouted with zeolite-cement using a multiple regression model (MRM) and a group method of data handling (GMDH)-type neural network.     

A scientometric analysis of international LIS journals: Productivity and characteristics

This paper presents a quantitative study of productivity, characteristics and various aspects of global publication in the field of library and information science (LIS). A total of 894 contributions published in 56 LIS journals indexed in SSCI during the years of 2000-2004 were analyzed. A total of 1361 authors had contributed publications during the five years. The overwhelming majority (89.93%) of them wrote one paper. The average number of authors per paper is 1.52. All the studied papers were published in English. The sum of research output of the authors form USA and UK reaches 70% of the total productivity. Most papers received few citations. Each article received on an average 1.6 citations and the LIS researchers cite mostly latest articles. About 48% of citing authors had tendency of self-citation. The productive authors, their contribution and authorship position are listed to indicate their productivity and degree of involvement in their research publications.     

钢管混凝土柱中的新型钢截面

在现代工程建设中,钢管混凝土（CFT）柱已逐渐成为高层建筑、桥梁等结构系统中的核心构件。在钢管混凝土的承载能力分析中有效参数有：钢与混凝土之间的粘结、钢管局部屈曲强度、混凝土徐变和连接处柱的负荷状态。考虑到这些有效参数,提议一种新截面,可用于高层建筑及大跨度桥梁。所提议钢截面的主要特点是内部纵向对称加劲肋。对此种截面（圆形和八角形）和钢管混凝土柱的常用截面进行轴向和循环荷载作用下的对比分析。同时采用有限元建模进行多种不同的分析。结果表明：新型截面在轴向和循环荷载下的强度和延性均有所增强,因此建议在施工中可采用此种截面。     

Photo-oxidation of phenol in aqueous solution: Toxicity of intermediates

The photodegradation of phenol was studied in a batch reactor system illuminated with a 400 W medium pressure mercury lamp. The effects of parameters such as pH, reaction time and initial phenol concentration on the photolytic degradation and toxicity assay have been studied. The experimental results have shown that lower pH and lower concentration of phenol favor the phenol degradation. The disappearance of phenol in each case approximately obeyed first-order kinetics with the apparent rate constants increasing with decreasing solute concentration. Bioassay tests showed that phenol was toxic to Daphnia magna and so resulted in quite low LC₅₀ values. Comparison of toxicity units (TU) between phenol and effluent toxicity has shown that TU value for effluent was 2.18 times lower than that obtained for phenol. Thus, photolysis is able to decrease the toxicity of by-products formed during the degradation of phenol.     

Compressibility indices of saturated clays by group method of data handling and genetic algorithms

Compression index (C _c) and recompression index (C _r) are used to estimate the consolidation settlement of fine-grained soils. As the determination of these indices from oedometer test is relatively time-consuming, in present research group method of data handling-type neural network optimized using genetic algorithms is used to estimate the compressibility indices (C _c and C _r) of saturated clays. C _c and C _r were modeled as a function of three variables including the initial void ratio (e ₀), liquid limit (LL) and specific gravity (G _s). Three hundred data sets collected from multiple sites in the province of Mazandaran, Iran, were used for the training and testing of the models. The predicted compressibility indices were compared with those of experimentally measured values to evaluate the performances of the proposed models. The results showed that appreciable improvement toward other correlations has been achieved. At the end, sensitivity analyses of the obtained models were carried out to evaluate the influence of input parameters on model outputs and showed that e ₀ and LL are the most influential parameters on C _c and C _r, respectively. Also, it has been demonstrated that the compressibility indices predicted by models are considerably influenced by changing measured G _s (uncertainty). In other words, the mean absolute percent error values increase greatly by G _s variation. Therefore, it needs more accuracy to measure this parameter in the laboratory.