Dysprosium doped copper oxide (Cu1-xDyxO) nanoparticles enabled bifunctional electrode for overall water splitting

The production of hydrogen, a favourable alternative to an unsustainable fossil fuel remains as a significant hurdle with the pertaining challenge in the design of proficient, highly productive and sustainable electrocatalyst for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, the dysprosium (Dy) doped copper oxide (Cu_1-xDy_xO) nanoparticles were synthesized via solution combustion technique and utilized as a non-noble metal based bi-functional electrocatalyst for overall water splitting. Due to the improved surface to volume ratio and conductivity, the optimized Cu_1-xDy_xO (x = 0.01, 0.02) electrocatalysts exhibited impressive HER and OER performance respectively in 1 M KOH delivering a current density of 10 mAcm^?2 at a potential of ?0.18 V vs RHE for HER and 1.53 V vs RHE for OER. Moreover, the Dy doped CuO electrocatalyst used as a bi-functional catalyst for overall water splitting achieved a potential of 1.56 V at a current density 10 mAcm^?2 and relatively high current density of 66 mAcm^?2 at a peak potential of 2 V. A long term stability of 24 h was achieved for a cell voltage of 2.2 V at a constant current density of 30 mAcm^?2 with only 10% of the initial current loss. This showcases the accumulative opportunity of dysprosium as a dopant in CuO nanoparticles for fabricating a highly effective and low-cost bi-functional electrocatalyst for overall water splitting.     

Radiation effects in a model ceramic for nuclear waste disposal

The safe immobilization of nuclear waste in geological repositories is one of the major scientific challenges facing humanity today. Crystalline ceramics hold the promise of locking up actinides from nuclear fuel and excess weapons plutonium in their structure thereby isolating them from the environment. This paper presents the atomistic details of radiation damage in a model ceramic, zircon.     

AH-64D main transmission accessory drive spur gear installation fault detections

The US Army has launched an aggressive program to implement condition based maintenance on its rotary wing assets. Condition Based Maintenance takes advantage of technology developments in the areas of machinery monitoring, signal processing and fault modeling to reduce the cost of ownership through improved maintenance procedures. Documenting the reduction in maintenance burden, cost savings and increased safety through early detection of helicopter faults is an important step in justifying the program. This paper describes a novel technique used to detect a serious fault in the accessory section of the AH-64D Apache main transmission. The technique determines if the primary or secondary clutch system is driving the aircraft accessories through a tachometer speed ratio. The method has identified three aircraft operating on the secondary system allowing Army maintenance crews to replace the affected transmissions and quickly restore the aircraft to operational status.     

Antifungal activity of five different essential oils in vapour phase for the control of Colletotrichum gloeosporioides and Lasiodiplodia theobromae in vitro and on mango

Mango fruit has high commercial value; however, major postharvest losses are encountered throughout the supply chain due to postharvest diseases. These results lead to the search for natural fungicide for postharvest diseases control. The antifungal effects of five essential oils (thyme, clove, cinnamon, anise and vitex) were assessed by disc volatilisation method. Thyme oil vapours at 5 μL per Petriplate, and clove and cinnamon oil at 8 μL per Petriplate showed 100% growth inhibition of mango pathogens in vitro. GC/MS analysis of essential oil showed thymol (23.88), o‐cymol (23.88) and terpinolene (23.88) as the major constituents of thyme oil. Clove and cinnamon oils contain 3‐allyl‐2‐methoxyphenol (37.42%) and benzofuran 3‐methyl (17.97%), respectively. Thyme oil as a fumigant at 66.7 μL L^?1 showed a significant (P < 0.05) inhibition on postharvest pathogens of mango fruits stored at 25 °C for 6 days. Results of our study suggest the possibility of using thyme oil as an alternate natural fungicide to manage postharvest diseases in mango.     

Enhancing the efficiency of alternating current driven organic light-emitting devices by optimizing the operation frequency

We report efficient and bright organic light-emitting devices operated by capacitive energy coupling. In this approach, the organic layers are enclosed between sputter-deposited hafnium dioxide layers to prevent charge carrier injection. When a sinusoidal voltage signal is applied to the electrodes, the devices emit bright green light whereas no detectable emission is generated upon application of a constant voltage. The efficiency of the process depends heavily on the frequency of the applied voltage signal. By optimizing the driving scheme, a record luminous efficacy for AC driven OLEDs of 2.7 lm/W at 500 cd/m² is achieved.     

Cytopathological and ultrastructural changes in the male reproductive organs of freshwater crab Paratelphusa jacquemontii (Rathbun) exposed to nurocombi

Accumulation of pollutants in the aquatic system has a high impact on the reproductive physiology of crustaceans. The objective of the present study was to assess the possible histopathological effects of combined chlorpyrifos and cypermethrin (nurocombi) exposure on reproductive tissue in male freshwater crab Paratelphusa jacquemontii using light and electron microscopy. The testis of experimental crabs showed disorganization of testicular lobules, increased inters cellular space, necrosis, and cellular damage in both germinal cells and Sertoli cells. The treated vas deferens exhibited epithelial degeneration, misshaped spermatophores, decline in the number of spermatophores, and dehiscence of spermatophore wall. These clinical manifestations expressed in crabs following the exposure of nurocombi significantly reduce the testicular activity and substantially inhibits the seminal secretions, which ultimately lead to impairment of reproduction.     

Selenium dioxide reaction of substituted diphenacyl sulfides: generation of α -ketoacids

The attempted selenium dioxide oxidation of substituted diphenacyl sulfides in anticipation of further functionalization led to a series of α -ketoacids 3 via oxidation followed by C?S bond cleavage. Two minor products, 5 and 6, have also been isolated and a mechanistic pathway for the formation of 3, 5 and 6 has been proposed.     

Wind Velocity Sensorless Maximum Power Point Tracking Algorithm in Grid-connected Wind Energy Conversion System

This article proposes a wind velocity sensorless hill-climb searching algorithm in the grid-connected field-oriented controlled permanent magnet synchronous generator based wind energy conversion system. The proposed method improves the speed and accuracy of initial tracking. Pseudo-optimum points are used to track the exact optimum points using the power versus speed characteristics of a wind turbine for various wind velocities. This research emphasizes that the pseudo-optimum points using the power versus speed characteristics are always less than and much nearer to the exact optimum points. The small-step forward tracking after pseudo-optimum points improves the accuracy of this algorithm. Moreover, this method improves the tracking speed for various wind velocities. The system used for this research consists of a back-to-back sinusoidal pulse-width modulation converter between the generator and the grid. The performance of the proposed method is analyzed mathematically and verified by simulation using MATLAB/Simulink software (The Mathworks, Natick; Massachusetts, USA).     

Lattice Boltzmann Simulation of Two- and Three-Dimensional Incompressible Thermal Flows

This work is concerned with the application of the thermal lattice Boltzmann method (TLBM) to compute incompressible two- and three-dimensional flows in cavities. Two convection test cases, namely, the laminar flow in a differentially heated square cavity and a cubic cavity, are numerically analyzed through TLBM. The internal energy density distribution function approach with two three-dimensional particle velocity models, namely, the 15-velocity and the 19-velocity, and a two-dimensional model, namely, the nine-velocity, have been used in the present work. Computations are carried out for laminar flows in a differentially heated square cavity and a cubical cavity (Rayleigh numbers = 10³ to 10⁵). The boundary conditions used are stable and of good accuracy. To lend credibility to the thermal lattice Boltzmann model square cavity results, they are further compared with those obtained from a finite-difference-based code developed for this purpose.