Identifying crop water stress using deep learning models

Neural Computing and Applications - The identification of water stress is a major challenge for timely and effective irrigation to ensure global food security and sustainable agriculture. Several...     

Determination of deuterium site occupancy in ZrCoD3 and its role in improved durability of Zr–Co–Ni deuterides against disproportionation

In the present study, we have for the first time reported the occupancy of deuterium in a new interstitial site of ZrCoD₃ which explain the hydrogen induced disproportionation behavior of ZrCo alloy. We have also reported the effect of Ni substitution on interstitial site occupancy of deuterium in ZrCo_1−xNi_xD₃, which in turn explains the improved durability of these Ni substituted deuterides against disproportionation. The crystal structure of the ZrCo_1−xNi_x (x = 0.0, 0.1, 0.2, 0.3) deuterides was investigated by X-ray powder diffraction and neutron diffraction methods. The XRD data reveals a single phase formation for all deuterides with varying Ni content (x). The neutron diffraction study shows that deuterium occupies a new site 8e in addition to 4c₂ and 8f₁. Additionally, the Zr–D distance in 8e site is shorter than that in ZrD₂. Therefore, increase in 8e site occupancy will in turn decreases the durability against disproportionation and vice-versa. Furthermore, the neutron diffraction reveals that occupancy of new 8e site decreases and its Zr–D distance increases with increase in Ni content, which explicate the higher durability against disproportionation for Ni rich compound.     

Equilibrium pressure measurements in the Li-N-H system by static manometric method

The equilibrium pressure over the phase mixture (Li₂NH + LiNH₂ + LiH) was measured from 343 to 683 K by static manometric method. The plot of ln (p_eq/p⁰) versus (1/T) showed three distinct temperature regions with different slopes. Analysis of the equilibrium gas composition in each temperature regions revealed that the equilibrium gas is a mixture of H₂, NH₃ and N₂ below 443 K whereas above 443 K, the equilibrium gas is mainly H₂. The enthalpy and entropy of the reaction of H₂ with Li₂NH to form LiNH₂ and LiH are found to be −55.0 ± 1.3 kJ?mol⁻¹ and −86 ± 2 J?K⁻¹?mol⁻¹, respectively at 523 K, where LiNH₂ exists in the solid state and −18.5 ± 0.5 kJ?mol⁻¹ and −26 ± 1 J?K⁻¹?mol⁻¹, respectively at 658 K, where LiNH₂ exists in the liquid state. The enthalpy and entropy of melting of solid LiNH₂ are calculated as 36.5 ± 1.4 kJ?mol⁻¹ and 60 ± 2 J?K⁻¹?mol⁻¹, respectively.     

装配式混凝土框架柱连接节点研究进展

装配式混凝土结构由于质量可靠、生产效率高、抗震性能好,近年来在国内得到快速发展。框架柱作为框架结构的重要受力构件,预制柱之间的连接节点则更是其关键部位,节点连接的受力可靠性将决定整体结构的抗震能力,节点连接的构造合理性将影响施工效率与质量。结合近年来国内外装配式混凝土框架柱连接节点领域的发展概况,从试验研究与数值模拟两方面进行总结,并分析了仍然存在的问题及未来发展方向,为我国装配式混凝土框架结构的发展提供参考。     

Optimization of microwave-vacuum drying of pomegranate arils

Pomegranate arils (Punica granatum L.) were dried in a microwave-vacuum drier up to a final moisture content of around 5–6 % (d.b.). The effect of microwave power level (25–95 W), vacuum pressure (25–195 mm Hg) and sample mass (65–235 g) on drying efficiency and some quality attributes (color, texture, rehydration ratio and sensory score) of dried pomegranate arils were analyzed by means of response surface methodology. A rotatable central composite design was used to develop models for the responses. Analysis of variance showed that a second order polynomial model predicted well the experimented data. All three process parameters microwave power, vacuum pressure and sample mass strongly affected quality attributes of dried pomegranate arils and drying efficiency. A lower vacuum pressure during drying resulted in better quality products. Optimum drying conditions of microwave power level of 80 W, vacuum pressure of 60 mm Hg and sample mass of 193.7 g were established for microwave-vacuum drying of pomegranate arils. Separate validation experiment was conducted at the derived optimum conditions to verify the predictions and adequacy of the models.     

RETROFITTING AN AUTOMATIC MANUFACTURING WORKCELL FOR STUDY OF OPEN ARCHITECTURE INTEGRATION OF MECHATRONIC SYSTEMS

Research work on plug-and-play open architecture and object-oriented mechatronic system integration is described. The original controllers of two popular industrial robot manipulators Puma 560 and IBM 7575 are completely retrofitted and integrated with a conveyor system to form a robot workcell. This robot workcell can be programmed to run under the Ch language environment. The outline of the Ch language, and the retrofitting strategy of the robot workcell will be described. A sample application program for simulated assembly operations of this robot workcell will be presented to demonstrate the underlying principles of open architecture integration of mechatronic systems under the programming paradigm of the Ch language environment.     

Radiation and slip effects on MHD point flow of nanofluid towards a stretching sheet with melting heat transfer

In the present paper, the melting heat transfer of a nanofluid over a stretching sheet is investigated. Magnetohydrodynamic stagnation point flow with thermal radiation and slip effects is considered for this study. The governing model of the flow is solved by Runge–Kutta fourth-order method using appropriate similarity transformations. Temperature and velocity fields are presented for various flow pertinent parameters. Nondimensional physical parameters such as Prandtl number, radiation parameter, Brownian motion parameter, Lewis number, thermophoresis parameter, magnetic parameter, and melting parameter on fluid velocity, heat, concentration, skin friction, Sherwood number, and Nusselt number are presented graphically and discussed numerically. Heat transfer rate can be increased by increasing slip, melting, or radiation parameter. Mass transfer increases for greater values of melting parameter or slip parameter while radiation parameter shows the opposite impact on mass transfer.     

Oxidation Kinetics of UZr<Subscript>2.3</Subscript> and U<Subscript>2</Subscript>Ti Alloys in Dry Air

The isothermal oxidation behavior of UZr_2.3 and U₂Ti alloys in dry air was studied by thermogravimetric technique in the temperature ranges of 773–848 and 548–623 K, respectively. The oxidation products were found to be U₃O₈ and ZrO₂ for UZr_2.3 and U₃O₈ and TiO₂ for U₂Ti by X-ray diffraction analysis. The oxidation kinetics were found to best fit into linear rate law for both the alloys in the temperature range of investigation and the lowest value of α (0.11 for UZr_2.3 and 0.12 for U₂Ti), which corresponds to the fraction of completed reaction. The linear rate constants (k) were evaluated from the oxidation data. The activation energies of oxidation reactions were calculated using the Arrhenius equation and found to be 161 kJ mol^?1 for UZr_2.3 and 88 kJ mol^?1 for U₂Ti.