Structural,Electrical and Photoresponse Properties of Si-based Diode with Organic Interfacial Layer Containing Novel Cyclotriphosphazene Compound

The electrical and photoresponse properties of Al/p-Si/organic layer/Al diode were investigated. Organic layer containing novel 2,2-bis[spiro(7,8-dioxy- 4-methylcoumarin)]-4,4,6,6-bis[spiro(2’,2”-dioxy-1’,1”- biphenylyl)]cyclotriphosphazene compound was coated by drop casting method on p-Si having ohmic contact. The structural characterization of novel cyclotriphosphazene compound was confirmed by using ¹H, ¹³C and ³¹P-NMR, elemental analysis and FT-IR spectroscopic techniques. The diode exhibits a photoconducting and photodiode behavior under solar light illumination. The electrical parameters such as ideality factor, barrier height and series resistance of the diode were determined from I-V characteristics. It is seen that the photocurrent of the diode under illumination is higher than dark current. Also, the frequency dependence of capacitance (C) and conductance (G) was explained on the basis of interface states. It is evaluated that the hybrid photodiode can be used as a photosensor in organic photodetector applications.     

Performance of ground blast furnace slag and ground basaltic pumice concrete against seawater attack

The aim of this research work is to investigate the seawater resistance of the concrete incorporating ground blast furnace slag (GBS) and ground basaltic pumice (GBP) each separately or both together. The variable investigated in this study is the level of fine aggregate replacement by GBS and GBP. Compressive strength measured on 150 mm cubes was used to assess the changes in the mechanical properties of concrete specimens exposed to seawater attack for 3 years.

Differential scanning calorimeter was used to evaluate the microstructure of the specimens under seawater attack. The effects of exposure were determined by direct measurement of the mass loss of steel bars, embedded in the mortar after 1, 2 and 3 years. The abrasion of concrete was also determined according to mass loss of specimens.

The test results showed that the presence of GBS and GBP had a beneficial effect on the compressive strength loss due to seawater attack and abrasion value. The results create perspectives of forecasting the durability of concrete depending on the types and amount of additives. Furthermore, specimen CSP80 was found to have higher seawater attack resistance than that of the reference concrete. This improvement can be explained partly by the decrease in the permeability of the specimen and partly by the seawater resistance of the additives. Additionally, the corrosion percentage obtained in the reference specimen was higher than all other specimens.     

Effect of wastewater composition on archaeal population diversity

Distribution and occurrence of Archaea and methanogenic activity in a laboratory scale, completely mixed anaerobic reactor treating pharmaceutical wastewaters were investigated and associated with reactor performance. The reactor was initially seeded with anaerobic digester sludge from an alcohol distillery wastewater treatment plant and was subjected to a three step feeding strategy. The feeding procedure involved gradual transition from a glucose containing feed to a solvent stripped pharmaceutical wastewater and then raw pharmaceutical wastewater. During the start-up period, over 90% COD removal efficiency at an organic loading rate (OLR) of 6 kg COD m(-3)d(-1) was achieved with glucose feeding, and acetoclastic methanogenic activity was 336 ml CH4 gTVS(-1)d(-1). At the end of the primary loading, when the feed contained solvent stripped pharmaceutical wastewater at full composition, 71% soluble COD removal efficiency was obtained and acetoclastic methanogenic activity decreased to half of the rate under glucose feed (166 ml CH4 gTVS(-1)d(-1)). At the end of secondary loading with 60% (w/v) raw pharmaceutical wastewater, COD removal dropped to zero and acetoclastic methanogenic activity fell to less than 10 ml CH4 gTVS(-1)d(-1). Throughout the course of the experiment, microbial community structure was monitored by DGGE analysis of 16S rRNA gene fragments. Five different archaeal taxa were identified and the predominant archaeal sequences belonged to methanogenic Archaea. Two of these showed greatest sequence identity with Methanobacterium formicicum and Methanosaeta concilii. The types of Archaea present changed little in response to changing feed composition but the relative contribution of different organisms identified in the archaeal DGGE profiles did change.     

The evaluation of some flexural properties of a denture base resin reinforced with various aesthetic fibers

This study was performed to determine whether some flexural properties of a denture base resin material could be improved through reinforcement with five types of aesthetic fibers at 3% concentration by weight and in 2, 4, and 6 mm length. Five specimens of similar dimensions were prepared for each of the test groups; base resin and the same resin with glass, rayon, polyester, nylon 6 and nylon 6,6 fibers in three different lengths. Flexural properties were evaluated by using a 3-point bending test. A visual examination was also made to determine mode of fracture of the specimens. The incorporation of different fibers in varying lengths had no significant effect on flexural strength of the resin. The specimens reinforced with nylon 6,6 fibers of 6 mm length showed the highest flexural strength. Young’s modulus and maximum load suggests that such reinforcement makes resin resistant to fracture.     

Pathophysiology and Molecular Imaging of Diabetic Foot Infections

Diabetic foot infection is the leading cause of non-traumatic lower limb amputations worldwide. In addition, diabetes mellitus and sequela of the disease are increasing in prevalence. In 2017, 9.4% of Americans were diagnosed with diabetes mellitus (DM). The growing pervasiveness and financial implications of diabetic foot infection (DFI) indicate an acute need for improved clinical assessment and treatment. Complex pathophysiology and suboptimal specificity of current non-invasive imaging modalities have made diagnosis and treatment response challenging. Current anatomical and molecular clinical imaging strategies have mainly targeted the host’s immune responses rather than the unique metabolism of the invading microorganism. Advances in imaging have the potential to reduce the impact of these problems and improve the assessment of DFI, particularly in distinguishing infection of soft tissue alone from osteomyelitis (OM). This review presents a summary of the known pathophysiology of DFI, the molecular basis of current and emerging diagnostic imaging techniques, and the mechanistic links of these imaging techniques to the pathophysiology of diabetic foot infections.     

Non-Newtonian laminar pulsating heat and fluid flow in plane duct

In the present study, laminar pulsating power-law momentum and heat transfer in a uniformly heated plane duct is studied analytically. Assuming that fully developed conditions exist both hydrodynamically and thermally, a perturbation series method is utilized to derive analytical solutions for the momentum and energy balance equations, and the amplitude is prescribed as the perturbation parameter. For varying values of the power-law index ( $n$), representing pseudoplastic, Newtonian, and dilatant fluids, effects of dimensionless amplitude ( $ϵ$) and frequency ( $F$) on periodic and period-averaged friction factor and Nusselt number are obtained. The results obtained for Newtonian fluid are shown to be in good harmony with the corresponding findings in the open literature.     

Quantitative analysis of cotton-polyester textile blends from near-infrared spectra

Quantitative analysis of textile blends and textile fabrics is currently of particular interest in the industrial context. In this frame, this work investigates whether the use of Fourier transform (FT) near-infrared (NIR) spectroscopy and chemometrics is powerful for rapid and accurate quantitative analysis of cotton-polyester content in blend products. As samples of the same composition have many sources of variability that affect NIR spectra, indirect prediction is particularly challenging and a large sample population is required to design robust calibration models. Thus, a total of more than three-hundred cotton-polyester samples were selected covering the range from the 0% to 100% cotton and the corresponding NIR reflectance spectra were measured on raw fabrics. The data set obtained was used to develop multivariate models for quantitative prediction from reference measurements. A successful approach was found to rely on partial least squares (PLS) regression combined with genetic algorithms (GAs) for wavelength selection. It involved evaluating a set of calibration models considering different spectral regions. The results obtained considering 27.5% of the original variables yielded a prediction error (RMSEP) of 2.3 in percent cotton content. It demonstrates that FT-NIR spectroscopy has the potential to be used in the textile industry for the prediction of the composition of cotton-polyester blends. As a further consequence, it was observed that the spectral preprocessing and the complexity of the model are simplified compared to the full-spectrum approach. Also, the relevancy of the spectral intervals retained after variable selection can be discussed.     

Integrated hydrogen production options based on renewable and nuclear energy sources

Due to varied global challenges, potential energy solutions are needed to reduce environmental impact and improve sustainability. Many of the renewable energy resources are of limited applicability due to their reliability, quality, quantity, and density. Thus, the need remains for additional sustainable and reliable energy sources that are sufficient for large-scale energy supply to complement and/or back up renewable energy sources. Nuclear energy has the potential to contribute a significant share of energy supply with very limited impacts to global climate change. Hydrogen production via thermochemical water decomposition is a potential process for direct utilization of nuclear thermal energy. Nuclear hydrogen and power systems can complement renewable energy sources by enabling them to meet a larger extent of global energy demand by providing energy when the wind does not blow, the sun does not shine, and geothermal and hydropower energies are not available. Thermochemical water splitting with a copper–chlorine (Cu–Cl) cycle could be linked with nuclear and selected renewable energy sources to decompose water into its constituents, oxygen and hydrogen, through intermediate copper and chlorine compounds. In this study, we present an integrated system approach to couple nuclear and renewable energy systems for hydrogen production. In this regard, nuclear and renewable energy systems are reviewed to establish some appropriate integrated system options for hydrogen production by a thermochemical cycle such as Cu–Cl cycle. Several possible applications involving nuclear independent and nuclear assisted renewable hydrogen production are proposed and discussed. Some of the considered options include storage of hydrogen and its conversion to electricity by fuel cells when needed.     

Structural and electrical properties of V-doped ZnO prepared by the solid state reaction

This paper reports the synthesis, crystal structure and electrical conductivity properties of vanadium (V)-doped zinc oxide (ZnO) powders (i.e. Zn_1?2X V _X O binary system, x = 0, 0.0025, 0.005, 0.0075 and in the range 0.01 ≤ x ≤ 0.15). I-phase samples, which were indexed as single phase with a hexagonal (wurtzite) structure in the V-doped ZnO binary system, were determined by X-ray diffraction (XRD). The limit solubility of V in the ZnO lattice at this temperature is 3 mol % at 950 °C. The impurity phase at 950 °C was determined as ZnV₂O₆ when compared with standart XRD data. The research focused on single I-phase ZnO samples which were synthesized at 950 °C because of the limit of the solubility range is widest at this temperature. It was observed that the lattice parameters a and c decreased with V doping concentration. The electrical conductivity of the pure ZnO and single I-phase samples were studied using the four-point probe dc method at temperatures between 100 and 950 °C in an air atmosphere. The electrical conductivity values of pure ZnO and 3 mol % V-doped ZnO samples at 100 °C were 2.75 × 10^?6 and 7.94 × 10^?5 Ω^?1 cm^?1, and at 950 °C they were 3.4 and 54.95 Ω^?1 cm^?1, respectively. In other words, the electrical conductivity increased with V doping concentration.     

A case study for influence of building thermal insulation on cooling load and air-conditioning system in the hot and humid regions

Ensuring the effective thermal insulation in regions, where the cooling requirement of building with respect to heating requirement is dominant, is very important from the aspect of energy economy. In this study, the influence of thermal insulation on the building cooling load and the cooling system in case of air-conditioning by an all-air central air-conditioning system was evaluated for a sample building located in Adana, based on the results of three different types of insulation (A, B and C-type buildings) according to the energy efficiency index defined in the Thermal Insulation Regulation used in Turkey. The operating costs of the air-conditioning system were calculated using cooling bin numbers. Life-cycle cost analysis was carried out utilizing the present-worth cost method. Results showed that both the initial and the operating costs of the air-conditioning system were reduced considerably for all three insulation thicknesses. However, the optimum results in view of economic measurements were obtained for a C-type building. The thickness of thermal insulation for the buildings in the southern Turkey should be determined according to the guidelines for a C-type building.