Mo Contact via High-Power Impulse Magnetron Sputtering on Polyimide Substrate

It has always been a huge challenge to prepare the Mo back contact of inorganic compound thin film solar cells (e.g., CIGS, CZTS, Sb2Se3) with good conductivity and adhesion at the same time. High-power impulse magnetron sputtering (HiPIMS) has been proposed as one solution to improve the properties of the thin film. In this study, the HiPIMS technology replaced the traditional DC power sputtering technology to deposit Mo back contact on polyimide (PI) substrates by adjusting the experimental parameters of HiPIMS, including working pressure and pulse DC bias. When the Mo back contact is prepared under a working pressure of 5 mTorr and bias voltage of −20 V, the conductivity of the Mo back contact is 9.9 × 10−6 Ωcm, the residual stress of 720 MPa, and the film still has good adhesion. Under the minimum radius of curvature of 10 mm, the resistivity change rate of Mo back contact does not increase by more than 15% regardless of the 1680 h or 1500 bending cycle tests, and the Mo film still has good adhesion in appearance. Experimental results show that, compared with traditional DC sputtering, HiPIMS coating technology has better conductivity and adhesion at the same time, and is especially suitable for PI substrates.

Study on Stress Management of College Teachers Based on Employee Assistance Program

Employee assistance program (EAP) is a service mode for organizations to effectively manage employees’ psychology and behavior to improve their work efficiency. As the problems of teachers’ stress and mental health are so serious that cannot be ignored, in order to understand their psychological stress and the demands for EAP, a survey was conducted among 386 college teachers, on their working pressure and pressure management by self-made questionnaires. The results show that besides the interpersonal relationships, teachers in colleges and universities have greater stress and the stress sources are more various, and they are supposed to have stronger subjective needs for the EAP. However, few college teachers have received EAP services, and the teachers who received EAP services are not the most stressed people. Thus, the EAP should be promoted inside universities to provide supportive services for teachers’ career development.

Pilot-Scale Test Results of Electrodialysis Bipolar Membrane for Reverse-Osmosis Concentrate Recovery

In this study, it is aimed to investigate the potential of electrodialysis bipolar membrane (EDBM) systems for the recovery of the concentrate originating from an organized industrial estate (OIE) wastewater treatment system with reverse osmosis (RO). Acids and bases were obtained from a pilot-scale treatment plant as a result of the research. Furthermore, the sustainability and affordability of acids and bases obtained by EDBM systems were investigated. Six cycles were carried out in continuous-flow mode with the EDBM system as batch cycles in the disposal of the concentrate and the production of acids and bases with the EDBM system. For each cycle, the EDBM system was operated for 66, 48, 66, and 80 min, respectively, and the last two cycles were operated for a total of 165 min (70 + 90) with 5 min of waiting. In the EDBM system, a working method was determined such that the cycle flow rate was 180 L/hour, energy to be given to the system was 25 V, and the working pressure was in the range of 0.8–2.5 bar. In the six cycles with the EDBM system, the concentrate, acid and base, conductivity, pH, and pressure increase values were investigated depending on time. Throughout all these studies, the cycles were continued over the products formed in the acid and base chamber. As a result of all the cycles, acid (HCl) production at a level of 1.44% and base (NaOH) production at a level of 2% were obtained.

Research on Key Factors of Sealing Performance of Combined Sealing Ring

In this study, the mechanical properties of a combined seal ring under different loads were numerically calculated using ANSYS. The effect of the working pressure and pre-compression ratio of a rubber O-ring on the contact stress of the combined seal ring was studied. The influence of the wear ring’s chamfer, thickness, and width on the contact stress and contact force of the combined seal ring was analyzed. Studies have shown that it is particularly important to select a compression ratio that is suitable for the working conditions. Under the same conditions of working pressure and compression ratio, upon increasing the wear ring chamfer, the contact pressure is decreased due to the decreasing contact bandwidth between the wear ring and the cylinder wall. This has little effect on the contact stress of the combined seal ring as well as the contact force, while the width of the wear ring is proportional to the latter.

AVALIAÇÃO DE DESEMPENHO DO MICROASPERSOR EM LINHA LATERAL E SIMULAÇÃO MATEMÁTICA DE SEU GRADIENTE DE ENERGIA

AVALIAÇÃO DE DESEMPENHO DO MICROASPERSOR EM LINHA LATERAL E SIMULAÇÃO MATEMÁTICA DE SEU GRADIENTE DE ENERGIA MADSON RAFAEL BARBALHO DA SILVA1; LÍVIA MARIA CAVALCANTE SILVA1; ANA CLÁUDIA DAVINO DOS SANTOS1; FABIANO SIMPLICIO BEZERRA1; CAIO SÉRGIO PEREIRA DE ARAÚJO1 E MANASSÉS MESQUITA DA SILVA1 1 Departamento de Engenharia Agrícola, Universidade Federal Rural de Pernambuco, Dom Manuel de Medeiros, s/n, Dois Irmãos, 52171-900, Recife, Pernambuco, Brasil. E-mail:[email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]. 1 RESUMO Objetivou-se avaliar o desempenho do microaspersor Agropolo modelo MC20 em diferentes condições hidráulicas, gerando informações para um melhor dimensionamento de sistemas de microirrigação e manejo da água em áreas irrigadas. A condução do projeto hidráulico para simulação do gradiente de energia em linhas laterais, considerou-se informações determinadas através da escolha de componentes do projeto. Foram extraídos do catálogo comercial do fabricante os pares de valores referentes a vazão e a pressão e, a partir destes, gerou-se a curva vazão-pressão, onde a simulação foi feita pelo Método Algébrico - Christiansen (MA) e Método Iterativo (SBS) – Back-Step. Para ambos métodos o microaspersor se comportou de maneira semelhante, quando submetido a condições sugeridas pelo fabricante, num espaçamento entre emissores de 5,2 m, usando tubos de polietilenos de diâmetro interno de 13 mm e uma pressão de serviço de 20 mca, admitindo uma variação de 10% da pressão. Foram calculados os coeficientes de uniformidade de pressão (CUp) e de vazão (CUq), ambos com valores superiores à 95%, demonstrando a excelência no desempenho do emissor. Palavras-chave: hidráulica, modelagem matemática, coeficiente de descarga. SILVA, M. R. B.; SILVA, L. M. C.; SANTOS, A. C. D.; BEZERRA, F. S.; ARAUJO, C. S. P.; SILVA, M. M. PERFORMANCE EVALUATION OF THE SIDE LINE MICROSPARENT AND MATHEMATICAL SIMULATION OF ITS ENERGY GRADIENT 2 ABSTRACT The objective was to evaluate the performance of the Agropolo model MC20 microsprinkler under different hydraulic conditions, generating information for a better design of micro-irrigation systems and water management in irrigated areas. The conduction of the hydraulic project to simulate the energy gradient in lateral lines, considered information determined through the choice of project components. The pairs of values ​​referring to flow and pressure were extracted from the manufacturer's commercial catalog and, from these, the flow-pressure curve was generated, where the simulation was performed using the Algebraic Method - Christiansen (MA) and Iterative Method (SBS) – Back-Step. For both methods, the microsprinkler behaved similarly, when subjected to conditions suggested by the manufacturer, in a spacing between emitters of 5.2 m, using polyethylene tubes with an internal diameter of 13 mm and a working pressure of 20 mca, admitting a 10% pressure variation. The uniformity of pressure (CUp) and flow (CUq) coefficients were calculated, both with values ​​above 95%, demonstrating the excellence in the performance of the emitter. Keywords: hydraulic, mathematical modeling, discharge coefficient.

An obstacle-avoiding and stiffness-tunable modular bionic soft robot

The aim of this work is to design and model a novel modular bionic soft robot for crawling and crossing obstacles. The modular bionic soft robot is composed of several serial driving soft modules, each module is composed of two parallel soft actuators. By analyzing the influence of working pressure and manufacturing size on the stiffness of the modular bionic soft robot, the nonlinear variable stiffness model of the modular bionic soft robot is established. Based on this model, the spatial states and design parameters of the modular bionic soft robot are discussed when the modular bionic soft robot can pass through the obstacle. Experiments show that when the inflation air pressure of the modular bionic soft robot is 70 kPa, its speed can reach 7.89 mm/s and the height of obstacles passed by it can reach 42.8 mm. The feasibility of the proposed modular bionic soft robot and nonlinear variable stiffness model is verified by locomotion experiments.

Microstructural Analysis of Copper Foil Etched and Annealed in ECR Plasma Reactor

Microstructural analysis of commercially available cold-rolled polycrystalline copper foil, etched and annealed in an in-house developed Electron Cyclotron Resonance (ECR) Plasma Enhanced Chemical Vapour Deposition (PE-CVD) reactor, have been carried out using x-ray diffraction (XRD) studies. The annealing experiments were carried out under a vacuum environment, keeping the working pressure of the reactor at 50×10-3 mbar, for three different time spans of 30 mins, 45 mins and 1 hour at 823 K (550 °C) and 923 K (650 °C) respectively in presence of hydrogen plasma. The XRD studies reveal the significance of annealing time at two different temperatures for the determination of physical and microstructural parameters such as the average grain size and micro-strain in copper lattice by Williamson-Hall (W-H) method.

Optimization Design of a Pneumatic Wheat-Shooting Device Based on Numerical Simulation and Field Test in Rice–Wheat Rotation Areas

In rice–wheat rotation areas of China, traditional wheat seeders have severe blockage, low working efficiency and poor seeding quality. In this study, a pneumatic shooting technology was designed, consisting mainly of a nozzle, shell and acceleration tube. To improve the sowing depth of the pneumatic shooting device, the response-surface methodology of structure parameters and CFD simulation technology was adopted in this work. The effects of working pressure, acceleration-tube diameter and throat distance on the steady airflow length (SAL) and steady airflow velocity (SAV) were studied by airflow field analysis, and the response-surface method was introduced to obtain the optimal parameter combination of the pneumatic shooting device for wheat. The optimal parameter combination was working pressure 686 kPa, acceleration tube diameter 8 mm and throat distance 20 mm. The simulation result showed that the optimized device of pneumatic shooting performs faster and has more stable airflow field characteristics in comparison to the initial device. The field test demonstrated that the optimized device has about 68% higher seeding depth than the initial device. The average field-seeding depth of the optimized device was 19.95 mm, which is about 68% higher than the initial device. The emergence rate for the optimized device was about 88.7% without obvious reduction. CFD and response-surface methods positively affect the optimization of pneumatic wheat-shooting devices, and the significance was also confirmed.

Study on nitrogen barrier protection of an airend oil-free compressor bearings in H2 compression

The oil free compressors were specially designed for air compression. The National Research and Development Institute for Gas Turbines COMOTI gained a great deal of experience in producing/designing certified oil injection screw compressors for the natural gas field and for several years it has been focusing its research on the use of “dry” (oil-free) compressors in natural gas compression and more recently in hydrogen compression. Working with an explosive gas, one of an idea was to use a nitrogen barrier in oil bearing sealing, which are open source of gases in the atmosphere for such compressors. Worldwide, on-site nitrogen generators have been developed for a purity range of 95…99.5%, and that nitrogen can be supplied in any environment conditions. The present paper will address nitrogen flow with low percentage of oxygen for bearing sealing at the working pressure, the nitrogen consumption, ideas for H2 re-injection and the influence over the global efficiency of the process. Due to the Energy Strategy worldwide, and the studies regarding production, transport and storage of hydrogen in natural gas network, COMOTI has involved researches in developing such possibilities and to express a point of view in existing research in the newly created industry.