Thermodynamical analysis of dry cooling tower and solar chimney power plant combination

Solar chimney power plant is one of the rather new technologies that can produce power from solar energy. Its high stack is one of the important parts of the system in which the differential density of air among its top and bottom sections causes air-flow. Dry cooling towers are used in industries for cooling condensing water by utilising this concept and generating air-flow. The structural and conceptual similarity between these two systems cause the feasibility of their combination and usage of waste energy in industries. In this article, a simple and useful analytical thermodynamic model is improved in order to estimate the thermodynamic flow properties for combining both systems. Results show that the stack height and diameter are effective parameters in recovery of power. Moreover, the results show that the collector area does not remarkably affect the system performance.     

气提式三重循环生物膜反应器用于制药废水的处理

采用气提式三重循环生物膜反应器（TLABR）处理制药废水，稳定阶段对COD和NH4^＋-N的去除率分别为73％和70％。当温度为27～30℃、pH=8．5时，反应器内形成了稳定的NO2^--N积累。同时，考察了不同HRT下高效反应器的处理效果，探讨了pH对反应器内发生的短程硝化效果的影响以及亚硝化菌对游离氨浓度的适应性。结果表明：在HRT为3、6、9h下，对COD和氨氮的去除率分别为65．3％、73．9％、75．1％和48．9％、68．4％、72．8％；NO2^--N积累率分别为92．7％、76．2％、69．7％；反应器出水水质稳定，体现了高效性和抗冲击负荷能力。     

Cement take estimation using neural networks and statistical analysis in Bakhtiari and Karun 4 dam sites,in south west of Iran

Bulletin of Engineering Geology and the Environment - Water seepage from dam foundations causes reservoir water loss and raises the risk of dam instability. One method of remediation for...     

Effect of different size of joint enlargement on seismic behavior of gravity load designed RC beam‐column connections

Effect of different size of planer joint enlargement as a noninvasive and practical strategy for seismic retrofit of gravity load designed external reinforced concrete beam‐column connections was experimentally investigated. The joint region was enlarged using steel angles that are mounted using prestressed cross‐ties. Reverse cyclic load tests on five half‐scale control and retrofitted external RC beam‐column connections were conducted. Three different size of planer joint enlargement being 180, 140, and 90 mm were considered for retrofitted specimens. The performance of the retrofitted specimens is compared with that of the control gravity load designed beam‐column connections, in terms of load–displacement hysteresis curve, energy dissipation and ductility capacities, and global strength and stiffness degradation behavior. The experimental results showed that increasing the size of planer joint enlargement significantly enhances the seismic capacity of the retrofitted connections, in terms of strength, stiffness, energy dissipation, and ductility capacity and also planer joint enlargement can relocate beam plastic hinges to outside the joint panel.     

Hard-rock LHD cost estimation using single and multiple regressions based on principal component analysis

In feasibility studies and mine planning, accurate and effective tools and methods facilitating cost estimation play an important role. Load-Haul-Dump (LHD) machines are a key loading and haulage equipment in most of the underground metal mines and hard rock tunnels. In this paper, a cost estimation model of these vehicles has been presented in the form of single and multivariable functions. These functions have been provided on the basis of costs types (i.e. capital and operating costs) and motor types (diesel and electric). Independent variables, in the single regression analysis is bucket capacity and in Multiple Linear Regression (MLR) analysis include bucket capacity, overall width, overall machine height and horse power (HP). The MLR is conducted in three steps. First, with the help of Principal Component Analysis (PCA), correlation between independent variables is omitted. Thereafter, significant PCs are selected and used as independent variables in the MLR functions. Finally, the cost relationships are established as functions of initial LHD variables. The mean absolute error rates are 11.59% and 6.87% for the single and multiple linear regression functions, respectively.     

Role of solute segregation on microstructure and mechanical properties of zircaloy-4

The Microstructure of two different lots of Zircaloy-4 was investigated by using a scanning electron microscope (SEM) attached to an energy dispersive system (EDS). The alloy containing Ni higher than the ASTM specification shows parallel plate structure with segregation of Ni, Fe, and Cr at the triple points of β-grains, and it failed during forging due to crack initiation. The second alloy having Ni content within the ASTM specification has basketweave morphology with minute segregation of Fe and Cr and was forged successfully. The absorbed energy is higher for the successfully forged alloy than for the alloy that failed during forging. It was also observed that the fracture started from the segregated area rich in Ni, Fe, and Cr, and propagated along the plate. The alloy with parallel plate structure is harder than the alloy with basketweave structure.     

A Short Review on Copper Calcium Titanate (CCTO) Electroceramic: Synthesis,Dielectric Properties,Film Deposition,and Sensing Application

Nano-Micro Letters - Electroceramic calcium copper titanates (CaCu3Ti4O12, CCTO), with high dielectric permittivities (ε) of approximately 105 and 104, respectively, for single crystal and...     

In vitro characterization of a novel tissue engineered based hybridized nano and micro structured collagen implant and its in vivo role on tenoinduction,tenoconduction, tenogenesis and tenointegration

Surgical reconstruction of large tendon defects is technically demanding. Tissue engineering is a new option. We produced a novel tissue engineered, collagen based, bioimplant and in vitro characterizations of the implant were investigated. In addition, we investigated role of the collagen implant on the healing of a large tendon defect model in rabbits. A two cm length of the left rabbit’s Achilles tendon was transected and discarded. The injured tendons of all the rabbits were repaired by Kessler pattern to create and maintain a 2 cm tendon gap. The collagen implant was inserted in the tendon defect of the treatment group (n = 30). The defect area was left intact in the control group (n = 30). The animals were euthanized at 60 days post injury (DPI) and the macro- micro- and nano- morphologies and the biomechanical characteristics of the tendon samples were studied. Differences of P < 0.05 were considered significant. The host graft interaction was followed at various stages of tendon healing, using pilot animals. At 60 DPI, a significant increase in number, diameter and density of the collagen fibrils, number and maturity of tenoblasts and tenocytes, alignment of the collagen fibrils and maturity of the elastic fibers were seen in the treated tendons when compared to the control ones (P < 0.05). Compared to the control lesions, number of inflammatory cells, amount of peritendinous adhesions and muscle fibrosis and atrophy, were significantly lower in the treated lesions (P < 0.05). Treatment also significantly increased load to failure, tensile strength and elastic modulus of the samples as compared with the control ones. The collagen implant properly incorporated with the healing tissue and was replaced by the new tendinous structure which was superior both ultra-structurally and physically than the loose areolar connective tissue regenerated in the control lesions. The results of this study may be valuable in the clinical practice.