Analysis of Flow and Heat Transfer in a Parallelogram Non‐Uniformly Heated Enclosure Filled with Porous Medium

The flow and heat transfer in a parallelogram enclosure filled with a porous medium is analyzed numerically. The heated bottom wall has a sinusoidal temperature distribution and side walls cooled isothermally while the upper wall is well insulated. Dimensionless Darcy law and energy equations are solved using the finite difference method along with the corresponding boundary condition. Computations were carried out for four inclination angles of side walls (γ = 45°, 60°, 75°, 90°) with different Rayleigh numbers (100≤Ra≤1000) and their effects on the flow field and heat transfer are discussed. It is found that the inclination angle has a significant effect on flow pattern and heat transfer and an increase in the angle leads to a decrease in the strength of the right vortex. The study also revealed that as the Rayleigh number increases at γ = 45°, another (third) vortex develops along the left wall and its strength enhances with Rayleigh number. At the end, a correlation is extracted from the numerical data which represents the relation between the Nusselt number, inclination angle, and the Rayleigh number. © 2010 Wiley Periodicals, Inc. Heat Trans Asian Res; 39(7): 497–506, 2010; Published online in Wiley Online Library ( wileyOnlinelibrary.com ). DOI 10.1002/htj.20312     

Collaborative and Reconfigurable Object Tracking

Many Applications perceive visual information through networks of embedded sensors. Intensive image processing computations have to be performed in order to process the perceived information. Such computations usually demand hardware implementations in order to exhibit real time performance. Furthermore, many of such applications are hard to be characterized a priori, since they take different paths according to events happening in the scene at runtime. Hence, reconfigurable hardware devices are the only viable platform for implementing such applications, providing both real time performance and dynamic adaptability for the system.In this paper, we present a collaborative and dynamically adaptive object tracking system that has been built in our lab. We exploit reconfigurable hardware devices embedded in a number of networked cameras in order to achieve our goal. We justify the need for dynamic adaptation of the system through scenarios and applications. Experimental results on a set of scenes advocate the fact that our system works effectively for different scenario of events through reconfiguration. Comparing results with non-adaptive implementations verify the fact that our approach improves system's robustness to scene variations and outperforms the traditional implementations.     

The wall–frame and the steel–concrete interactions in composite shear walls

The nonlinear pushover analyses of 24 composite steel plate shear walls (CSPSWs), 24 corresponding steel plate shear walls (SPSWs), and 24 corresponding frames are conducted. CSPSWs have different aspect ratios and infill steel plate thicknesses. The study aims to understand the wall–frame and steel–concrete interactions. The infill steel plate thickness and aspect ratio of CSPSW are the main parameters of the study. In CSPSWs, the percentage of absorbed shear forces by the infill composite wall is always greater than the infill plate of its corresponding SPSW. The percentage of shear in the composite wall is constant at the initial stage of loading up to a drift of 0.15–0.2%. By increasing the drift, the shear yielding of steel plate leads to a reduction of the shear force absorption. The reduction continues until the bulk of shear stiffness of CSPSW is provided by the frame. At the beginning of lateral loading, steel–concrete interactions increase until shear yield of steel plate. Following this stage, a sudden decrease takes place in shear force absorption of reinforced concrete (RC) panel. The reason is that, at the lower drifts, the steel plate has a tendency for elastic buckling, which is prevented by the RC panel. Finally, the shear force absorption remains approximately constant in the RC panel.     

Steel–concrete composite shear walls using precast high performance fiber reinforced concrete panels

In this research, seismic performance of composite steel plate shear walls (CSPSWs) using high performance fiber reinforced concrete (HPFRC) panels is experimentally and numerically investigated. Three one‐story one‐bay CSPSW specimens using precast HPFRC panels were designed and fabricated for cyclic quasi‐static experiments. The HPFRC panels of composite shear wall specimens did not have any steel rebars. The main purpose of the study was to understand the effects of rigid and semirigid HPFRC panels on the seismic behavior of the system. Shear capacity, ultimate shear strength, lateral stiffness, energy dissipation, and ductility ratios of the specimens are evaluated. The experimental results demonstrate that specimens were able to resist lateral load up to at least interstory drift of 6%. Using HPFRC panels, CSPSW specimens becomes stiffer in the elastic region, and the yield displacement of the shear wall is decreased; therefore, the ductility ratio of the system is increased. It should be noted that ultimate shear strength, initial elastic stiffness, and energy absorption of specimens with an HPFRC panel on one side or both sides of the infill steel plate were approximately the same. However, using two HPFRC panels is not economical in comparison with CSPSW with an HPFRC panel on one side. Additionally, the second panel increases the seismic mass of the structure.     

Eicosapentaenoic acid promotes apoptosis in Ramos cells <Emphasis Type="Italic">via</Emphasis> activation of caspase-3 and -9

Eicosapentaenoic acid (EPA; 20∶5n−3) may reduce the cell number in cultured leukemia/lymphoma cells owing to reduced cell proliferation, induction of cell death, or a combination of these processes. EPA has been shown to promote apoptosis in Ramos cells, and our present study was focused on a possible cell cycle arrest and the pathways by which the apoptotic process is induced. Apoptosis may proceed along the intrinsic (mitochondrial) or the extrinsic (death receptor) pathway, which are mediated via different caspases. Caspases are a class of homologous cysteine proteases recognized as pivotal mediators of apoptosis. We investigated whether EPA affects progression of the cell cycle or promotes apoptosis directly. By incorporation of [³H]thymidine and [³H]valine, we showed that DNA, as well as protein synthesis, was reduced after incubation of Ramos cells with EPA for 6h. We monitored cell cycle distribution by 5-bromo-2′-deoxyuridine staining and observed no cell cycle arrest in the EPA-incubated cells. Incubation of cells with EPA caused PS-flipping, as demonstrated by annexin V-binding (flow cytometry), and cleavage of poly(ADP-ribose) polymerase measured by Western blot analysis. Furthermore, we observed increased activity of caspase-3 and-9, but not of caspase-8. Whereas inhibitors of caspase-3 and-9 reduced EPA-induced apoptosis, inhibition of caspase-8 did not. This suggests that EPA may promote apoptosis via the intrinsic pathway in Ramos cells. Thus, the reduction in cell number can be explained by a direct apoptotic effect of EPA rather than via cell cycle arrest.     

The Effects of Richness,Relative Permeability Curves,and Skin in Well Test Analysis of Gas Condensate Reservoirs

Abstract

Gas condensate reservoirs have more complicated performance than other categories because possessing intermediate compositions leads to more complex thermodynamic and phase behavior. When the well bottom hole flowing pressure falls below the dew point, condensate liquid builds up around the wellbore, causing a reduction in gas permeability and well productivity. Well test analysis is now commonly used to identify and quantify near-wellbore effects, reservoir behavior quantifying the skin and reservoir boundaries. Finding all this information from well tests in gas condensate reservoirs, however, is challenging. The present article demonstrates the effect of the richness, relative permeability curves, and skin in well test analysis of gas condensate reservoirs.     

Sliced Designs for Multi-Platform Online Experiments

Abstract

Multivariate testing is a popular method to improve websites, mobile apps, and email campaigns. A unique aspect of testing in the online space is that it needs to be conducted across multiple platforms such as a desktop and a smartphone. The existing experimental design literature does not offer precise guidance for such a multi-platform context. In this article, we introduce a multi-platform design framework that allows us to measure the effect of the design factors for each platform and the interaction effect of the design factors with platforms. Substantively, the resulting designs are of great importance for testing digital campaigns across platforms. We illustrate this in an empirical email application to maximize engagement for a digital magazine. We introduce a novel “sliced effect hierarchy principle” and develop design criteria to generate factorial designs for multi-platform experiments. To help construct such designs, we prove a theorem that connects the proposed designs to the well-known minimum aberration designs. We find that experimental versions made for one platform should be similar to other platforms. From the standpoint of real-world application, such homogeneous subdesigns are cheaper to implement. To assist practitioners, we provide an algorithm to construct the designs that we propose.     

Cu/Oil nanofluids flow over a semi‐infinite plate accounting an experimental model

In this study, the flow of Cu/oil nanofluids over an impermeable semi‐infinite plate was investigated. A complete single‐phase modeling of nanofluids flowing over a semi‐infinite plate was performed, bringing into account, real experimental data of oil‐based nanofluids. The empirical correlations revealed that the viscosity and thermal conductivity of the pure oil and oil‐based nanofluids strongly depend on temperature. The similarity transformation method was utilized to transform governing partial differential equations into coupled nonlinear ordinary differential equations solved by employing the standard Runge–Kutta. The results showed that even low volumetric fraction of copper/oil nanofluids noticeably enhanced the heat transfer; however, such behavior was not predicted accounting the classic modeling of nanofluids. Furthermore, both hydrodynamics and thermal characteristics were reliant on the thermal boundary conditions, which this seems to have received a marginal focus in the existing literature.     

A novel TS Fuzzy-GMDH model optimized by PSO to determine the deformation values of rock material

Neural Computing and Applications - Since determining the rock deformation directly in the laboratory is costly and time consuming, it is important to reliably determine/estimate this parameter...     

Measuring chemical emissions from wet products--development of a new measurement technique

A new approach for estimating chemical emissions from wet products has been developed. The concept of such approach is that emission rates can be estimated from the amount of target chemicals in the product as a function of evaporation time. Samples were placed under a laboratory fume hood under controlled conditions (surface air velocity and temperature). Weight losses of the product were monitored and residuals at different time intervals were chemically analyzed. Emission factors of the target chemicals were then calculated based on the weight losses and residual levels of the chemicals. To demonstrate the applicability of this approach, two wet products with very different physical characteristics, one liquid and one paste-like viscous fluid, were chosen. Emissions of two principle chemicals in the products, decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) were measured. The influences of initial sample weight, surface air velocity, and temperature were investigated. The calculated emission profiles were compared with those obtained from the chamber method. The described approach could be used as an alternative screening method for emission tests of wet products, especially for compounds with low vapour pressure when sink effect poses serious challenge in traditional chamber-based emission tests.