Unit Surface Research Articles

Amino-functionalized porous PDVB with high adsorption and regeneration performance for fluoride removal from water

Excessive fluoride anions in drinking water are toxic to the health of human beings. In this article, an effective fluoride removal adsorbent on the basis of amino-functionalized porous polydivinylbenzene (PDVB) was prepared through low cost processes, which included solvothermal preparation of porous PDVB and subsequent surface amino-functionalization. The obtained amino-functionalized porous PDVB (A-PDVB) has high surface area of 443 m2 g−1 and high adsorption capacity towards fluoride anion up to 105.9 mg g−1. Considering adsorbents surface area, the adsorption capacity per unit surface area of A-PDVB is 0.24 mg m−2 which is more than 4 times of porous PDVB (0.058 mg m−2). The enhanced adsorption performance of A-PDVB was due to amino groups electrostatic interaction coupled with hydrogen bond binding with fluoride anions. In addition, the amino-functionalized porous PDVB could be regenerated in high efficiency under alkaline conditions. This work not only exhibits the possibility of A-PDVB for application as an environment-friendly adsorbent for fluoride removal but also gives an insight into understanding mechanism of the fluoride anions adsorption onto amino-functionalized porous PDVB.

Parameterization of the characteristics of the melt pool using the video diagnostics of the laser metal deposition process

The dependences of the geometric characteristics of the melt bath on the scanning velocity and radiation power during laser metal deposition (LMD) are shown. The data were obtained experimentally at different values of the intensity Is up to 60 kW/cm2 in the range of changes in the specific energy per unit surface area Es (20…60) j/mm2 using the high-speed video camera installed in coaxial scheme. A powder (40…100) microns of PR-Kh18N9 austenitic steel with a mass flow rate of 8.4 g/min was used. It is found that the length of the melt pool L increases with the growth of Is and practically does not depend on the scanning velocity in the range (5…10) mm/s. The melt volume is estimated taking into account the measured track height. At the same velocity, the volume of the melt increases with the value of the Is exceeding the threshold. The value of threshold increases with increasing velocity. The volume of the melt increases with the specific energy Es. The relationship between the geometric characteristics of the melt bath and the shape of the track formed in the LMD process is shown.

Experimental analysis of invitro biocompatibility of nano modified titanium alloys and stainless steel

The aim of this paper is to conduct an experimental analysis in invitro biocompatibility of nano modified titanium alloys. The titanium alloy was etched with sulfuric acid and hydrochloric acid above 200oC. The biocompatibility study was carried on the modified titanium plate. The cell culture was carried out the results are expressed as the number of attached cells to the unit surface of the material of the plastic culture plate. SEM analysis and DNA isolation and electrophoresis were carried out. Modified titanium shows more cell attachment. Innovation carried out in this research is the fabrication of porous material using white gold alloy. White gold alloy was prepared by nanoscale modification of surface by acid etching. Nonporous are seen on the surface. The SEM, EDAX analysis confirms the modifications of the surface by acid etching.

Fractal Model for Drag Reduction on Multiscale Nonwetting Rough Surfaces.

Rough surfaces in contact with a flow of fluid exhibit alternating no-slip and free shear boundary conditions at the solid-liquid and air-liquid interfaces, respectively, thereby potentially offering drag reduction benefits. The balance between the dynamic pressure in the flow and the restoring capillary pressure in the interasperity spaces determines the stability of the Cassie state of wettability and is a function of the relative extent of no-slip and free shear regions per unit surface area. In the present study, using a fractal representation of rough surface topography, an analytical model is developed to quantify the stability of the Cassie state of wettability as well as drag reduction and the friction factor for laminar flow in a rectangular channel between nonwetting multiscale rough surfaces. A systematic study is conducted to quantify the effects of fractal parameters of the surfaces and the flow Reynolds number on drag reduction and the friction factor. The studies are used to develop friction factor curves extending the classical Moody diagram to hydrophobic and superhydrophobic surfaces. On the basis of the studies, regime maps are derived for estimating the extent of drag reduction offered by hydrophobic and superhydrophobic surfaces, revealing that superhydrophobic surfaces do not always offer the best drag reduction performance. The application of the fractal model to practical topographies of nonwetting surfaces of copper, aluminum, and zinc oxide fabricated via electrodeposition and etching is also discussed.

Electromagnetic field correlators and the Casimir effect for planar boundaries in AdS spacetime with application in braneworlds

We evaluate the correlators for the vector potential and for the field strength tensor of the electromagnetic field in the geometry of two parallel planar plates in AdS spacetime. Two types of boundary conditions are considered on the plates. The first one is a generalization of perfect conductor boundary condition and the second one corresponds to the confining boundary conditions. By using the expressions for the correlators, the vacuum expectation values (VEVs) of the photon condensate and of the electric and magnetic fields squared are investigated. As another important local characteristic of the vacuum state we consider the VEV of the energy-momentum tensor. The Casimir forces acting on the plates are decomposed into the self-action and interaction parts. It is shown that the interaction forces are attractive for both types of boundary conditions. At separations between the plates larger than the curvature radius of the background geometry they decay exponentially as functions of the proper distance. The self-action force per unit surface of a single plate does not depend on its location and depending on the boundary condition and on the number of spatial dimensions can be either attractive or repulsive with respect to the AdS boundary. By using the generalized zeta function technique we also evaluate the total Casimir energy. Applications are given in $Z_{2}$-symmetric braneworld models of the Randall-Sundrum type for vector fields with even and odd parities.

Analysis of quality and prediction of external and internal egg traits in Mexican native turkey hens

This study aimed to evaluate external and internal quality traits and determine prediction equations for some of these traits in eggs of Mexican native turkey hens. A total of 72 eggs from native turkey hens in the laying stage raised in rural municipality of Villaflores, Chiapas were measured. The external traits evaluated were: egg weight (EW), polar diameter (PD), equatorial diameter (ED), egg shape index (SI), shell weight (SW), shell percentage (SP), egg surface area (ESA) and shell weight per unit surface area (SSA). The internal traits were: albumen height (AH), yolk height (YH), albumen weight (AW), yolk weight (YW), Haugh units (HU), albumen percentage (AP), yolk percentage (YP) and yolk color (YC). The data were analyzed with descriptive statistics and Pearson correlation coefficients (r) and linear regression using the SAS program, ver. 9.4. The values obtained for the external egg quality traits showed greater variability. Pearson's correlation coefficients between external and internal traits were positive and moderately significant (P <0.05), as well as highly significant (P <0.0001), and ranged from r = 0.31 (EW vs PD) to r = 0.99 (ED vs ESA). All linear regression equations to predict EW, SW, AW and YW were found to be significant (<.0001). The best predictors of EW were PD, SI, SW and ESA (R2 = 76%). SW and YW traits can be adequately predicted using the EW and SI values together (R2 = 59% and R2 = 74%, respectively), while the AW can be predicted from the EW (R2 = 33%). Based on the results obtained, it is suggested to implement selection programs to improve the quality parameters of the native turkey hen egg in Mexico.

Effects of ecofriendly synthesized calcium nanoparticles with biocompatible Sargassum latifolium algae extract supplementation on egg quality and scanning electron microscopy images of the eggshell of aged laying hens

In the present study, 200 Brown commercial egg-type layers (60 wk old) were used to study the effects of different levels of ecofriendly synthesis of calcium (Ca) nanoparticles (0.0, 0.50, 1.0, and 1.5 g/kg diet) with biocompatible Sargassum latifolium algae extract (SL-CaNps) on exterior egg quality traits, electronic microscopic view of eggshells, Ca and phosphorus (P) retention, serum Ca and P concentrations, and the histology of the uterus. Hens fed with dietary SL-CaNps powder had higher egg weight and shell weight % values than those of the control group. All SL-CaNps treatment groups had the greatest values of shell weight per unit surface area and shell thickness. Dietary supplementation of SL-CaNps at graded levels up to 1.5 g/kg diet had higher serum Ca and inorganic P levels than that of the control. Laying hens fed with SL-CaNps-added diets had beneficial effects on shell ultrastructure in terms of well-developed palisade and mammillary layers. The numbers of apical cells along the branched tubular gland were greater in SL-CaNps-treated groups than those of control. Conclusively, supplementing SL-CaNps powder up to 1.5 g/kg to the diet of laying hens improved eggshell thickness, shell weight% and shell weight per unit surface and has no adverse effect on their eggshell quality or electronic microscopic view of their eggshell.

Investigation of Energy Saving Potential in Buildings Using Novel Developed Lightweight Concrete

In this study, three different composite materials were produced from mixtures of natural and waste materials in different proportions. The produced composites were used to determine the insulation thickness of exterior walls of buildings located in 12 provinces selected from the four different climate zones of Turkey. The selection of provinces was made according to Turkish standard TS 825. The produced materials are thermal insulation elements that can be used instead of construction elements, such as brick, on the exterior walls of the buildings. In this study, only the heating of the buildings was considered and the number of heating degree days of the provinces was taken into account to determine the insulation thickness. The life cycle cost analysis method was used to determine the optimum insulation thickness. It was determined that the optimum insulation thickness values calculated for four different fuel types for the selected provinces varied between 0.170 m and 1.401 m. The annual energy requirement for the unit surface area of the exterior walls of the insulated buildings was determined to be 11,213–965,715 kJ·m−2 per year. Moreover, it was determined that the insulation costs ranged between $ 22,841 m−2 and $ 114,841 m−2, and the payback period ranged from approximately 2.5 to 6.5 years. It was concluded that using these new types of materials in the determined regions were advantageous in terms of thermal insulation, fire resistance, mechanical properties, production costs, extra labor costs, and optimum insulation thickness.

Use of Neural Networks to Forecast Seismic Hazard Expressed by Number of Tremors Per Unit of Surface

The seismic and rock burst hazard should be considered as one of the most important hazards in Polish hard coal and copper ore mines. Over the last several years, Upper Silesia has witnessed a constant process of limiting the extraction of hard coal. Despite a significant decrease in production, no reduction in the number of registered high-energy tremors with energy higher than 105 J. is observed. Therefore, it is important to develop the existing methods for assessing the state of seismic hazard and seeking new ways to estimate the level of this threat. The article presents the results of research aimed at determining the possibility of using artificial neural networks to forecast the level of seismicity induced by mining operation. The data used in the conducted research came from the area of operation of a heavily seismic USCB mine. The presented research results showed that in the case of the discussed area, the use of the new tool, which is an artificial neural network, allowed to obtain good results of the forecast of the number of tremors. For the data set in question, the neural network with optimal architecture is composed of twelve neurons in the entrance layer, two neurons with bipolar characteristics in the hidden layer and one neuron with linear or bipolar characteristics in the initial layer. The results of calculations made for the highly seismic area of mining works carried out in a hard coal mine confirmed the possibility of using neural networks to estimate the changes in the size of induced seismicity associated with the deposit operation.

Effects of Varying Dietary DL-Methionine Levels on Productive and Reproductive Performance, Egg Quality, and Blood Biochemical Parameters of Quail Breeders.

Simple SummaryThis study investigated the effects of different DL-methionine levels on quail breeders kept from 8–16 weeks of age. The results revealed that using DL-methionine at levels of 0.5 or 1.5 g/kg improved the liver and kidney functions, lipid profile, immunity and antioxidant parameters of quail breeders.The present study was carried out to study the effects of varying dietary DL-methionine (0, 0.5, 1.5, 2.5, and 3.5 g/kg) levels on the productive and reproductive performance, egg quality and blood biochemical parameters of quail breeders. In total, 150 mature Japanese quails at eight weeks of age were randomly allotted to five groups of 30 for each group. Each group included five replicates, each of six quails (four females and two males). The results showed that egg number, egg weight and egg mass were higher (p < 0.05) with the addition of all DL-methionine levels than that of the control group. Quails from the control group had a lower feed intake (p < 0.001) and a worse feed conversion ratio (FCR) than those from the DL-methionine-treated groups. Supplementation of DL-methionine up to 2.5 g/kg in quail diets increased fertility and hatchability percentages. Birds fed DL-methionine at 1.5 g/kg had the best egg production indices, better FCR and the highest values of fertility and hatchability. Egg weight, yolk %, Haugh unit, egg shape index and unit surface shell weight (USSW) were increased and eggshell % was decreased in quail supplemented with DL-methionine levels compared with the control quail (p < 0.05). Dietary DL-methionine levels did not affect (p > 0.05) the hemoglobin (Hb), red blood cells (RBCs), white blood cells (WBCs) and packed cell volume (PCV) of quails. DL-methionine levels (0.5 and 2.5 g/kg) augmented lymphocytes and basophile (p < 0.05). Low DL-methionine levels (0.5 or 1.5 g/kg) improved liver enzymes and kidney functions. Dietary DL-methionine levels (except 3.5 g/kg) declined serum lactate dehydrogenase (LDH) and decreased lipid profile parameters (except high-density lipoprotein—HDL). Supplementation of DL-methionine at 0.5 and 1.5 g/kg increased immunoglobulin (IgG, IgM and IgA) and superoxide dismutase (SOD), total antioxidant capacity (TAC), catalase (CAT) and reduced glutathione (GSH) (p < 0.001) compared with the control. In conclusion, dietary supplementation of DL-methionine (1.5 g/kg) can enhance the reproductive performance and egg quality of quail breeders. DL-methionine use at levels of 0.5 or 1.5 g/kg improved the liver and kidney functions, lipid profile, immunity and antioxidant parameters of Japanese quail.

K-Modified Co–Mn–Al Mixed Oxide—Effect of Calcination Temperature on N2O Conversion in the Presence of H2O and NOx

The effect of calcination temperature (500–700 °C) on physico-chemical properties and catalytic activity of 2 wt. % K/Co-Mn-Al mixed oxide for N2O decomposition was investigated. Catalysts were characterized by inductively coupled plasma spectroscopy (ICP), X-ray powder diffraction (XRD), temperature-programmed reduction by hydrogen (TPR-H2), temperature-programmed desorption of CO2 (TPD-CO2), temperature-programmed desorption of NO (TPD-NO), X-ray photoelectron spectrometry (XPS) and N2 physisorption. It was found that the increase in calcination temperature caused gradual crystallization of Co-Mn-Al mixed oxide, which manifested itself in the decrease in Co2+/Co3+ and Mn3+/Mn4+ surface molar ratio, the increase in mean crystallite size leading to lowering of specific surface area and poorer reducibility. Higher surface K content normalized per unit surface led to the increase in surface basicity and adsorbed NO per unit surface. The effect of calcination temperature on catalytic activity was significant mainly in the presence of NOx, as the optimal calcination temperature of 500 °C is necessary to ensure sufficient low surface basicity, leading to the highest catalytic activity. Observed NO inhibition was caused by the formation of surface mononitrosyl species bonded to tetrahedral metal sites or nitrite species, which are stable at reaction temperatures up to 450 °C and block active sites for N2O decomposition.

Aerobic granular sludge: Impact of size distribution on nitrification capacity

The relationship between ammonia oxidation rate, nitrifiers population, and modelled aerobic zone volume in different granule sizes was investigated using aerobic granular sludge from a pilot-scale reactor. The pilot was fed with centrate and secondary effluent amended with acetate as the main carbon source. The maximum specific ammonia oxidation rates and community composition of different aerobic granular sludge size fractions were evaluated by batch tests, quantitative PCR, and genomic analysis. Small (331µm) granules had a 4.72 ± 0.09 times higher maximum specific ammonia oxidizing rate per 1 gVSS, and a 4.05 ± 0.17 times higher specific amoA gene copy number than large (2225µm) granules per 1 gram of wet biomass. However, when related to surface area, small granules had 1.43 ± 0.01 times lower maximum specific ammonia oxidation rate and a 1.66 ± 0.04 times lower specific amoA gene copy number per unit surface than large granules. Experimental results aligned with modeling results in which smaller granules had a higher specific aerobic zone volume to biomass and lower specific aerobic zone volume to surface area. Aerobic granular sludge reactors having the same average diameter of granules may have very different proportions of granule size fractions and hence possess different nitrification rates. Therefore, instead of the commonly reported average granule diameter, a new method was proposed to determine the aerobic volume density per sample, which correlated well with the nitrification rate. This work provides a roadmap to control nitrification capacity by two methods: (a) crushing larger granules into smaller fractions, or (b) increasing the mixed liquor suspended solid concentration to increase the total aerobic zone volume of the system.

Influence of Vertical and Radial Distances of Nano-Resistors in SSI-LEDs on Light Intensity Distributions

Broad-band white light emission phenomena from a novel type of solid-state incandescent light emitting device (SSI-LED) was reported by Kuo's group [1-4]. The device is made from the dielectric breakdown of a metal-oxide-semiconductor (MOS) capacitor with a high-k gate dielectric deposited over a p-type Si wafer [1-4]. The device emits light from the thermal excitation of the nano-sized conductive paths in the high-k stack upon the passage of a large current. This blackbody radiation phenomenon is similar to that of the incandescent light bulb [4]. In this paper, the light intensity distributions from nano-resistors with various vertical and radial distances are investigated by simulation.Equation 1, also known as Stefan-Boltzmann law [5, 6], quantifies the total energy radiated per unit surface area of a black body across all wavelengths per unit time j* that is directly proportional to the fourth power of the black body's thermodynamic temperature T, i.e., j* = eσT4 (1)where e is the emissivity of the object (e = 1 for perfect black body) and σ is the Stefan–Boltzmann constant. Therefore, the total power P radiated from an object of surface area A can be given by the following equation P = Aj* = eσT4 (2)Assuming that the nano-resistors formed in the high-k stack behave as point light sources, we can calculate the intensity at a given vertical distance from the nano-resistors. The following equation, i.e., the intensity of light emitted from a point source I is inversely proportional to the square of the distance r, is used in the calculation I = P/ 4πr2 (3)The resultant intensity due to all the nano-resistors at any given vertical distance can then be simply obtained by scalar addition of intensity from each of the individual nano-resistors. In order to simulate the light intensity distribution from the SSI-LED, authors made some assumptions based on experimental observations. For instance, nano-resistors with cylindrical geometry are assumed to be formed and distributed randomly across the high-k gate stack [1]. Further it is assumed that all nano-resistors in a SSI-LED are of the same diameter, i.e., 100 nm. In actual, nano-resistors formed on the same device are of different sizes, i.e., the number decreases with the increase of the diameter size [4]. Previously, it has been reported that light emitted from the SSI-LED is similar to that from the conductive paths at the temperature of 4,000 K [7]. The same temperature of 4,000 K was used to calculate the total radiated power P in equation 1. Although it was reported earlier that the temperature across the cross-section of a nano-resistor could vary with its diameter size [7], here we assume it to be constant. Moreover, the effect of thin film ITO gate on intensity of emitted light is neglected for simplifying current calculations. The Beer-Lambert Law could be used to account for the transmittance of light across ITO thin film to further improve the intensity distribution estimation.Figure 1(a) shows the light intensity distributions of two 100 nm diameter nano-resistor sources observed at varying distance above the nano-resistor/ITO gate interface. Figure 1(b) shows the low and high magnification images of a SSI-LED with the ZrHfO gate dielectric. It can be clearly seen that at the low magnification, the whole SSI-LED appears as a single light dot, i.e., individual nano-resistors are unresolvable [1]. At the high magnification, which is similar to the short distance case, peaks of the two light dots are observable. This study will be extended in 3-D to better understand the light distribution. The result will be discussed in detail. Moreover, the effect of the radial separation distance of the nano-resistors on the light intensity distribution will also be presented and discussed.[1] Y. Kuo and C.-C. Lin, Appl. Phys. Lett., 102, 031117 (2013).[2] Y. Kuo and C.-C. Lin, ECS Solid-State Lett. , 2, Q59 (2013).[3] Y. Kuo and C.-C. Lin, Solid-State Electron., 89, 120 (2013).[4] C.-C. Lin and Y. Kuo, Appl. Phys. Lett., 106, 121107 (2015).[5] Stefan J, Sitzber. Math.-Nat.wiss. Cl. kaiserlichen Akad. Wiss., 79, 391 (1879).[6] Boltzmann L, Ann. Phys. Chem., 22, 291 (1884)[7] A. Shukla and Y. Kuo, ECS Trans., Submitted, April 2020. Figure 1

Effect of gamma irradiation on structural, morphological and optical properties of thermal spray pyrolysis deposited CuO thin film

This study reports the influences of gamma irradiation (GI) in the range of 20–100 kGy on CuO thin films via thermal spray pyrolysis technique on the glass substrates. The results demonstrate significant influences of GI on the crystallographic, microstructural and optical characteristics of CuO thin films. The obtained XRD results showed that the crystallinity of the films deteriorates by gradually decreasing crystallite size (from 59.13 to 46 nm) as applied gamma doses increases. However, the basic monoclinic crystal structure remains same. The dislocation density and lattice strain increased with the rise of GI absorbed dose due to the creation of defects. The values of number of crystallites per unit surface area increased as dose increased indicating the abundance of crystallization of nano CuO thin films. A UV–Vis–NIR spectrophotometer was utilized to determine the optical properties and obtained results indicated that the optical energy band gap (OBG) energies reduced from 2.00 to 1.72 eV as the doses increased from 0 to 100 kGy. No distinctions of the monoclinic phase of virgin CuO thin film have been perceived under applied absorbed doses, notwithstanding the slight deterioration of the crystallinity and narrowing the OBG.

Urban air quality and meteorology on opposite sides of the Alps: The Lyon and Torino case studies

Several European urban areas are characterised by low air quality due to high local emission per unit surface. A further key feature can be related to the pollutant load due to adverse local meteo-climatic conditions. This study aims to compare the two urban agglomerations of Torino and Lyon – located on opposite sides of the Alps and characterised by similar size and population – to enlighten the role of meteorology on local pollutant dispersion. The assessment of air quality has been developed by monitoring network data, emissions analysis and the SIRANE urban dispersion model. Although the two agglomerations have similar NOX and PM10 emissions, the simulation results show higher ground level concentrations in Torino. To quantify the effect of meteorology on this excess of concentrations, we run simulations in Torino imposing the meteorological conditions of Lyon and vice versa. This implies an overall reduction of ground level concentrations in the city centre of Torino between 20% and 40% (analogously, Lyon concentrations increase by a similar amount). These results show the peculiar difficulties faced by Po valley's cities in maintaining pollution levels below regulatory thresholds and highlight the need of systemic policies and site-specific mitigation to reduce air pollution health risks.

Removal of Fluoride from Water Using a Calcium-Modified Dairy Manure-Derived Biochar.

This study investigated the removal of fluoride from water using a calcium-modified dairy manure-derived biochar (Ca-DM500). The Ca-DM500 showed a 3.82 - 8.86 times higher removal of fluoride from water than the original (uncoated) manure-derived biochar (DM500). This is primarily attributed to strong precipitation/complexation between fluoride and calcium. The Freundlich and Redlich-Peterson sorption isotherm models better described the experimental data than the Langmuir model. Additionally, the removal kinetics were well described by the intraparticle diffusion model. The Ca-DM500 showed high reactivity per unit surface area [0.0001, 0.03, 0.16 mg F per m2 for Douglas fir-derived biochar (DF-BC), DM500. and Ca-DM500, respectively] for retention of fluoride reflecting the importance of surface complexation. The copresence of anions reduced removal by Ca-DM500 in the order . The sorption behavior of fluoride in a continuous fixed-bed column was consistent with the Thomas model. Column studies demonstrated that the Ca-DM500 shows a strong affinity for fluoride, a low release potential, and a stable (unreduced) removal capacity through regeneration and reuse cycles.

Experimental Study on the Mechanical Properties of Rock Fracture after Grouting Reinforcement

Grouting reinforcement plays an important role in repairing fractures and improving the strength of the surrounding rock. To address practical engineering challenges such as caving and chip off-falling of surrounding rock in deep roadways, normal splitting was adopted to prefabricate fractures on rock samples gathered from underground coal mines. This was done to better match the rock fracture specimen with actual conditions. Based on the elementary unit of a fracture surface, systematic experiments were conducted on the tensile properties of rock fractures after grouting reinforcement, and the shear properties were studied after considering the presence of gas. As per the results, the tensile strength of rock fractures increased with the increase in viscosity of grout, but the overall tensile strength was relatively low. The overall tensile effect of surrounding rock was improved less by grouting approach. When the presence of fracture gas in grouting was considered, the peak shear strength of fractures after grouting was 8.34–29.9% less than that without considering the fracture gas. The cemented pore surface produced by unsaturated cementation in the grouting reinforcement was the main cause of reduction in cohesion and frictional angle of rock fractures. The conclusions of this study have great significance for guiding engineering grouting and evaluating the grouting effect.

Theoretical modeling and simulation-based assessment of graded-bandgap AlGaAs/GaAs electron-injection cathode

The electron emission model of a negative electron affinity graded-bandgap AlGaAs/GaAs electron-injection cathode was developed from two-dimensional continuity equations. The emission current was obtained from a simulation of the model, and the emission current efficiency and emission current per unit length were calculated. Based on the simulation results and preparation conditions, the range of optimum parameters for the cathode structure were determined. The ranges of optimum thickness for the p-AlGaAs and the graded-bandgap p-AlGaAs layers were 0.05–0.15 μm and 0.1–0.3 μm, respectively. The optimum width of the base electrode ranged from 1 to 4 μm, and the optimum molar ratios of Al in the p-AlGaAs and the n-AlGaAs layers were 0.2–0.3 and 0.4–0.5, respectively. This abrupt PN heterojunction inhibited the hole current and increased the emission current efficiency, with a maximum value of 25.3%. According to the emission current per unit length, the optimum range of width of emission unit surface was 6 to 10 μm, and the peak emission current per unit length reached 43.2 μA/μm.

Textile wing fabric for emergency response UAS

The fabrics used to manufacture parachutes and paragliders must have several specific characteristics: the mass of fabric per unit of surface must be low while the other physical-mechanical characteristics (the axial breaking strength load, the relative and absolute elongation, the tear resistance of the fabric and the assemblies, air permeability) must have high values. The paper deals with the analysis of qualitative aspects of several parachute fabrics that are used as a baseline in the development of a novel fabric. The results of experiments have materialized in statistical data, diagrams and graphs and their interpretation leads to the determination of the fabric variant that best meets the requirements of the destination. The destination is a patent pending inflatable wing design that utilizes a single skin construction and solid reinforcements in the sewing for shape stability. It is worth noting that the experimental results were compared with values indicated in specific international testing norms.

Sarı tüy rengindeki (Coturnix japonica) bıldırcınlarda farklı yaş ve depolama sürelerinin yumurta kalite özellikleri üzerine etkisi

Amaç: Sarı tüy renkli japon bıldırcınlarında 8, 12, 16, 20, 24, 28 ve 32 haftalık yaşlarda 7 ve 14 gün süreyle depolanan kuluçkalık yumurtaların iç ve dış kalite özellikleri araştırılmıştır.Yöntem ve Bulgular: Yaş ve depolama sürelerinin yumurtalarda dış ve iç kalite özellikleri üzerine etkisini belirme amacıyla 8-32 haftalar arasında 7 ayrı yaş dönemleri yumurtaların 0, 7 ve 14 gün süre ile depolanması araştırmanın yöntemini oluşturmaktadır. Yumurtanın depolama süresinin bağıl ağırlık kaybına etkili olduğu görülmüştür. Yumurta ağırlığı üzerine yaşın etkisi önemli bulunmuş, deneme başlangıcında (8. hafta) 11.67 g olan yumurta ağırlığı deneme sonunda (32. hafta) 12.15 g değerini almıştır Yumurta eninin yumurta boyuna oranı şeklinde ifade edilen şekil indeksi 8 haftalık yaşta en yüksek, 32 haftalık yaşta en düşük belirlenmiştir. Ak indeksi üzerine hayvan yaşı, depolama süresi ve yaş x depolama süresi arasındaki interaksiyon önemli bulunmuştur. Haugh birimi depolama süresi ve hayvan yaşından etkilenmiş, depolama süresi ile yaş arasındaki interaksiyon da etkili olmuştur. Depolama işlemi yapılmayan kontrol grubunda sarı indeks değeri, 7 ve 14 günlük depolama sürelerine göre daha düşük olup uygulamalar arası farklılık önemli bulunmuştur. Ak yüzdesi üzerine depolama süresi, yaş ve depolama süresi ile yaş arasındaki interaksiyon önemli olmuştur. Sarı yüzdesi depolama süresinden etkilenmemiş ancak yaşa bağlı olarak değişmiştir. Artan depolama süresine bağlı olarak sarı indeks değeri azalmıştır. Birim yüzey alanı başına kabuk ağırlığı depolama süresi ve hayvan yaşına göre değişmiştir. Gözenek sayısı üzerine hayvan yaşı etkili iken depolama süresinin etkisi önemsiz olmuştur.Genel Yorum: Sarı tüy rengindeki japon bıldırcınlarında yumurta iç ve dış kalite özellikleri üzerine anaç yaşı, depolama süresi ve çevresel faktörlerin etkisi önemli düzeyde bulunmuştur.Çalışmanın Önemi ve Etkisi: Elde edilen sonuçların gelecekte planlanacak çalışmalar için bilgi sağlayacağı beklenmektedir.