Recent Integral Representations for Thermoelastic Green's Functions and Many Examples of Their Exact Analytical Expressions

This article is devoted to derivation of new integral representations for the main thermoelastic Green's functions (MTGFs), based on the presentation of solutions of respective Lamé elliptic differential equations via Green's functions for the Poisson equation (GFPEs). The newly derived integral representations in Cartesian coordinates permitted the proof of a theorem about constructive formulas for MTGFs expressed in terms of respective GFPEs. The thermoelastic displacements are generated by a unitary heat source, applied in an arbitrary inner point of a generalized boundary values problem (BVP) of thermoelasticity for an octant at different homogeneous mechanical and thermal boundary conditions, prescribed on its marginal quadrants. According to the constructive formulas obtained, the derivation of MTGFs for about 20 BVPs for a plane, a half-plane, a quadrant, a space, a quarter-space, and an octant may be obtained by changing the respective well-known GFPEs. All results obtained are in terms of elementary functions with many examples of their validation. Two new MTGFs for quarter-space and octant, together with some of their graphical computer evaluations, are also included. The main advantages of the proposed approach in comparison with the GΘ convolution method for MTGFs constructing are: First, it is not necessary to derive the functions of influence of a unit concentrated force onto elastic volume dilatation - Θ⁽ⁱ⁾. Second, it is not necessary to calculate an integral of the product of the volume dilatation and Green's function in heat conduction. By using the proposed approach it is possible to extend obtained results for Cartesian domains onto areas of any orthogonal system of coordinates.     

Effects of illumination on electrical parameters of Ag/n-CdO/p-Si diode

The current–voltage (I–V) characteristics of the Ag/n-CdO/p-Si diode were investigated under various white light (visible light) illuminations. The electrical parameters such as ideality factor (n), zero-bias-barrier height (Φ_b) and series resistance (R_S) of Ag/n-CdO/p-Si MIS diodes were determined by using the forward bias current–voltage measurements. The Ag/n-CdO/p-Si diode exhibits a non-ideal behavior due to the interfacial layer, the interface states and the series resistance. The ideality factor is increased, while the barrier height is decreased with decreasing illumination intensities. The values of R_S obtained from Cheung and Norde methods are decreased with increasing illumination intensity. The distribution profile of the interface states (N_SS) as a function of energy distribution (E_SS − E_V) was extracted from the forward I–V measurements under various illumination intensities. The interface state densities were observed to be strongly illumination dependent and are decreased with increasing illumination intensities.     

Synthesis of new organic semiconductors based on poly(2‐anilinoethanol) doped with different acids and investigation of their electro‐optical properties

The polyaniline (PANI) was synthesized using different dopant acids (iminodiacetic, methanesulfonic, phosphoric, and boron trifuoride) using oxidative polymerization method. These obtained new polymers were characterized by using spectrophotometric methods such as FTIR, UV–vis. The calculated value of the optical energy gap for the doped investigated polymer was reached to 3.70 eV for PANI‐OH doped by boron trifuoride. The conductivity of the polymers was also investigated. The direct current (dc) conductivity as a function of temperature for the doped polymers has been studied. The results show increase in the conductivity with increase in temperature. Also, the value of dc conductivity at room temperature was found to be greater than that of the undoped PANI by nearly one to four orders of magnitude with respect to the used dopant acid. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

PLANAR COPPER PLATING AND ELECTROPOLISHING TECHNIQUES

Electrochemical mechanical deposition (ECMD) is a novel technique that has the ability to deposit planar conductive films on non planar substrate surfaces. This technique involves electrochemical deposition (ECD) while simultaneously polishing the substrate surface. Preferential deposition of the conductor into the cavities on the substrate surface may be achieved through two different mechanisms. The first mechanism is more mechanical in nature and it involves material removal from the top surface. The second mechanism is more chemical in nature, and it involves enhancing the deposition into the cavities where mechanical sweeping does not reach and reducing deposition onto surfaces that are swept. In this study we demonstrate that in an ECMD process, low-pressure mechanical sweeping of the wafer surface during copper plating can establish a differential in the activity of the organic accelerator species between the surface and the cavity regions of the substrate and thus give rise to bottom-up filling in even the lowest aspect-ratio cavities. Planar layers obtained by the ECMD technique have been successfully employed in an electrochemical polishing technique for stress-free removal of Cu.     

PRODUCTION OF BIOFUEL FROM SOFT SHELL OF PISTACHIO (PISTACIA VERA L.)

Soft shell of pistachio (Pistacia vera L.) pyrolysis experiments were performed in a fixed-bed reactor to produce bio-oil. The effects of temperature, heating rate, and sweep gas (N₂) flow rates on the yields and compositions of products were investigated. Pyrolysis runs were performed using reactor temperatures between 350° and 500°C with heating rates of 15° and 50°C/min. Nitrogen flow rates varied between 50 and 200 cm³/min and mean particle size was 0.8 mm. The maximum bio-oil yield of 33.18% was obtained in a nitrogen atmosphere with nitrogen flow rate of 150 cm³/min and at 450°C pyrolysis temperature with a heating rate of 50°C/min.The elemental analysis and gross heating value of the bio-oil were determined, and then the chemical composition of the bio-oil was investigated using chromatographic and spectroscopic techniques. The chemical characterization has shown that the bio-oil obtained from soft shell of pistachio can be used as a renewable fuel and chemical feedstock.     

Enzymatic Glycerolysis of Palm and Palm Kernel Oils

Glycerolysis of palm and palm kernel oils were carried out using commercial lipases from Candida antarctica (Novozym 435) and Mucor miehei (Novozym 388) as catalyst (500 units lipase/g oil) at 40°C and with an oil:glycerol molar ratio of 1:2 in a solvent-free system. Novozym 435 catalyzed the glycerolysis of palm and palm kernel oils giving reaction products in similar compositions. Partial acylglycerols contents of the glycerolysis products obtained from palm and palm kernel oils were 64% (wt) and 66% (wt), respectively. However, partial acylglycerols contents of the glycerolysis products obtained from palm and palm kernel oils conducted with Novozym 388 as catalyst at the same conditions were 44% (wt) and 56% (wt), respectively. On the other hand, free fatty acid contents of the glycerolysis products of palm and palm kernel oils obtained using Novozym 388 were higher, 25–30% (wt), than those obtained by Novozym 435, 4–5% (wt). The monoacylglycerols fraction with the highest content of oleic acid, 62.7% (wt), was obtained from the palm kernel oil glycerolysis reaction catalyzed by Novozym 435.     

Determination of Chromium Species in Various Medicinal Plants Consumed in Hatay Region in Turkey

In this study, 22 species of medicinal plants (anise, centaury, chamomile, fennel, flax, green tea, indian hemp, laurel, licorice, linden, marestail, melissa, nettle, oat, red clover, riesenfenchel, rosehip, rosemary, sage, senna tea, yam, yarrow) were taken from five different local herbalists in Hatay. Chromium concentrations were determined by inductively coupled plasma-atomic emission spectroscopy. The highest chromium concentrations were detected in chamomile (4.21 ± 0.18 mg kg^?1), licorice (2.80 ± 0.12 mg kg^?1), melissa (2.71 ± 0.10 mg kg^?1), marestail (2.66 ± 0.10 mg kg^?1), and anise (1.98 ± 0.06 mg kg^?1). Minimal concentrations of chromium were found in riesenfenchel (0.33 ± 0.01 mg kg^?1), red clover (0.37 ± 0.01 mg kg^?1), centaury (0.43 ± 0.01 mg kg^?1), senna tea (0.49 ± 0.01 mg kg^?1), and linden (0.50 ± 0.01 mg kg^?1). Cr(III) and Cr(VI) concentrations in medicinal herbs were found in the range of 0.26–3.12 mg kg^?1 and 0.07–1.09 mg kg^?1, respectively.     

Statistical Modeling of β-galactosidase Inhibition During Lactose Hydrolysis

A statistical model approach called response surface methodology was used to describe the product and substrate inhibition effect on β-galactosidase enzyme during lactose hydrolysis. The effect of independent variables, namely the initial concentrations of lactose (73 – 146 mM), galactose (44 – 122 mM) and glucose (83 – 167 mM) on the reaction rate of β-galactosidase was evaluated. The enzymatic reaction rate was influenced by both combined and individual effects of all the substrate and products. Although, glucose acted as an activator at low lactose and low galactose concentrations, glucose caused the inhibition of β-galactosidase at higher concentrations of lactose and galactose. The effect of galactose concentration on β-galactosidase enzyme was in the direction of inhibition. At low lactose concentrations and high glucose concentrations, galactose concentration became more effective on the reaction rate.     

Thermal degradation kinetics of anthocyanins and visual colour of Urmu mulberry (Morus nigra L.)

Urmu mulberry (Morus nigra L.) juice was concentrated from 15.02 to 45.20 °Brix by rotary vacuum evaporator at 40 °C. The objectives of this study were to determine the titratable acidity, soluble solid content, antioxidant capacity, total monomeric anthocyanins and total phenolic matter in prepared concentrate, to investigate the thermal degradation kinetics of anthocyanins and Hunter colour parameters (L^∗, a^∗, b^∗) and total colour difference (TCD^∗) and to develop a relationship between visual colour and anthocyanin during thermal processing at 60, 70 and 80 °C. Monomeric anthocyanin degradation showed a first order reaction kinetics. The zero order, first order and a combined kinetics model were applied to the changes in Hunter colour parameters (L^∗, a^∗ and b^∗) and total colour difference (TCD^∗). All colour parameters followed an apparent combined kinetics model. The degradation of anthocyanins showed positive correlation with a^∗, b^∗ and L^∗ and negative correlation with TCD^∗.     

Performance and emission characteristics of an CI engine fueled with diesel–biodiesel–bioethanol blends

The paper presents the experimental results obtained concerning performances and pollution of a diesel engine fueled with diesel–biodiesel–ethanol blends compared with diesel fuel in laboratory tests. The main properties of the researched fuels are presented within this paper, in comparison with classical diesel fuel (chemical composition, density, kinematic viscosity, cold filter plugging point, flash point). Engines’ performances were evaluated by determining the brake specific fuel consumption and brake thermal efficiency. For pollution evaluation the emissions of CO, CO₂, NO_x, HC and smoke have been measured. An increasing of brake specific fuel consumption has been observed, especially at lower engines’ loads, with maximum 32.4%, reducing engine brake thermal efficiency with maximum 21.7%. CO emissions decrease, especially at high loads with maximum 59%, on the basis of CO₂ increased emissions. NO_x emissions slightly increase, especially at partial and high loads, meanwhile HC and smoke emissions decrease in all engines’ load cycles.