An experimental study on plunging depth of density currents

Mass density of the current flows is the one of the important problem in the hydraulics of the dam reservoir. Plunge point occurs when the mass density current penetrates in the stagnant fluid. Recognition the place of this point is very important because of clearing the boundary of the density current flow and ambient fluid. In this study the influences of bed slope and hydraulic parameters on plunging depth were experimentally investigated. The results show that the slope has a minor effect on the plunging depth. The height of plunging depth is increased by increasing the density of the current flow. Also increasing the densimetric Froude number caused of decreasing the plunging depth. Finally an equation was proposed to estimate the plunging depth using as function of flow characteristics.     

Heat Transfer and Energy Analysis of a Pusher Type Reheating Furnace Using Oxygen Enhanced Air for Combustion

 Oxy-fuel firing is more energy efficient and environmental friendly than conventional air-fuel firing and its application for reheating furnaces has begun since 90s. In this study, a computational methodology is presented to predict the steady heat transfer to the billets and temperature distribution in a continuous Pusher type reheating furnace which combustion air is enhanced by oxygen. The furnace is modeled as 2D radiating medium and Weighted Sum of Gray Gases model is used for absorption coefficient. The billets are moved in constant speed through zones of furnace. Radiative heat flux calculated from the radiative heat exchange within the furnace is modeled using the FVM considering the effects of furnace walls and billets. Energy consumption per ton of steel, production rate and thermal efficiency of furnace, and trend of NOx emission in various levels of oxygen enrichment is investigated by comparison with baseline furnace (21% O2 in air).     

Thermal and flow analysis of a magneto-hydrodynamic micropump

A study of transient fully developed laminar flow and temperature distribution in a magnetohydrodynamic (MHD) micropump is presented. The micropump is driven using the Lorentz force which is induced as a result of interaction between an applied electric field and a perpendicular magnetic field. The governing equations are solved analytically by an eigenfunction expansion method, and numerically by a finite-difference (ADI) method. The numerical and analytical results are found to be in good agreement with each other. The effect of different parameters on the transient velocity and temperature, such as aspect ratio, Hartman number, Prandtl number, and Eckert number is studied. The results obtained showed that controlling the flow and the temperature can be achieved by controlling the potential difference, the magnetic flux, and by a good choice of the electrical conductivity.     

Study on the physical and mechanical properties of electron‐beam‐irradiated Vinyl ester/TiO2 nanocomposites

The effect of electron beam irradiation on the physical and mechanical properties of vinyl ester nanocomposites containing various amounts of TiO₂ nanoparticles was investigated. The fracture toughness, surface hardness, and water uptake measurements were carried out to investigate alterations in the physical and mechanical properties owing to electron beam exposure. In this regard, it was attempted to infer the impact of TiO₂ nanoparticles on the structural changes varying the irradiation dose. The results were then explained based on crosslinking and chain scission phenomena. Moreover, scanning electron microscopy was used to assess the degree of TiO₂ dispersion within the polymer matrix. J. VINYL ADDIT. TECHNOL., 22:110–116, 2016. © 2014 Society of Plastics Engineers     

Understanding improvisation in construction through antecedents,behaviours and consequences

Improvisation is a deliberate, spontaneous and rational decision-making process that helps address emerging issues or unplanned work. Traditional management avoids relying on improvisation as it indicates deviation from the pre-planned procedures and standards. However, improvisational practices continue to exist within numerous uncertain environments such as construction where improvised actions emerge even though they are not encouraged. The purpose of this study is to develop a better understanding of the improvisational practices occurring in construction and recognize the factors contributing to successful improvisation. This study elucidates antecedents, behaviours and consequences of improvisation in various construction operations. Surveys were conducted among different construction professionals to understand improvisation on real-life construction projects. Statistical analyses show that personal experience and the type of organization a person works for have a significant effect on the outcomes of improvisation. In addition, results highlight the most frequent antecedents that trigger the need for improvisation to complete a certain task. The outcomes of this study can help managers and decision makers in the construction industry identify personal, organizational and other specific characteristics that may improve the practice of improvisation for complementing planning processes rather than undermining them.     

General Barnes-Godunova-Levin type inequalities for Sugeno integral

Integral inequalities play important roles in classical probability and measure theory. Non-additive measure is a generalization of additive probability measure. Sugeno’s integral is a useful tool in several theoretical and applied statistics which has been built on non-additive measure. For instance, in decision theory, the Sugeno integral is a median, which is indeed a qualitative counterpart to the averaging operation underlying expected utility. In this paper, Barnes-Godunova-Levin type inequalities for the Sugeno integral on abstract spaces are studied in a rather general form and, for this, we introduce some new technics for the treatment of concave functions in the Sugeno integration context. Also, several examples are given to illustrate the validity of this inequality. Moreover, a strengthened version of Barnes-Godunova-Levin type inequality for Sugeno integrals on a real interval based on a binary operation ★ is presented.     

Improvement of deep drawing conditions utilizing LDPE/Gr/MWCNT composite films

The main purpose of this work is reduction of friction coefficient in deep drawing die to improve the deep drawing conditions of St37 blank sheet. For this purpose, graphite (Gr) and multi wall carbon nanotube (MWCNT) were introduced into low density poly(ethylene) (LDPE), and blown composite films were prepared by co-rotating extruder. The composite films (LDPE/Gr, LDPE/MWCNT, and LDPE/Gr/MWCNT) were used as lubricants in deep drawing of St37 blanks. Gr was added in the content of 5, 10, 15, 20 and 25 wt%, and MWCNT was added in content of 0.1, 0.5, 1 and 2 wt%. The effect of filler content on drawing depth, forming force, and thinning of St37 blanks was investigated. The results of experiments indicated that MWCNT was more beneficial than Gr in improving the drawing depth, forming force, and thinning of St37 blanks when Gr and MWCNT were singly combined. Deep drawing tests using LDPE/Gr/MWCNT hybrid composite films revealed that hybrid composite films were more suitable in improvement of deep drawing conditions of St37 blanks. Minimum thinning (8.5%), forming force (49470 N), and maximum drawing depth (13.5 mm) were obtained using LDPE/15 wt% Gr/2 wt% MWCNT hybrid composite film.