Investigation of rockfall-prone road cut slope near Lengpui Airport,Mizoram, India

Rockfall is one of severe natural hazards that are frequently reported in northeast region of India. It carries rock block falling from the cliff with high velocities and energies which can result in damages to vehicles, disruption to transportation, injuries and fatalities. The massive rockfall event which occurred in April 2017 on the highway NH-44A, near Lengpui Airport, blocked the traffic for 1 d, and fortunately, no casualties were reported as the event occurred in the night. This is the only highway connecting the Aizawl city to the airport and the region is highly prone to rockfall events. Hence assessment of rockfall along this highway is necessary. In the current study, rockfall hazard assessment has been carried out on three locations by rockfall hazard rating system (RHRS). During pre-failure analysis, the result shows that most hazardous slopes have RHRS score of 639. The slopes were found to be vulnerable and later on the rockfall activity occurred. Three-dimensional (3D) stability analysis has been carried out using 3DEC software package to analyze the failure behavior and to decide the rockfall-prone zone (unstable blocks) for slope. The total displacement of 2.24 cm and velocity of 2.25 mm/s of the failed block have been observed in the numerical analysis. Further, the rockfall vulnerable zone (unstable blocks) is considered to determine the parameters such as run-out distance, bounce height and energies of the falling rock blocks. The maximum total kinetic energy of 5047 kJ has been observed in the numerical analysis with the maximum run-out distance up to 18 m.     

Photoelectrochemical water splitting with nanocrystalline Zn1−xRuxO thin films

Thin films of nanocrystalline Zn_1−xRu_xO are deposited on ITO substrate by sol–gel. XRD and EDX analysis indicated dominant evolution of wurtzite ZnO with crystallite size in the range 26–43 nm. With no evidence of phase segregation, Ru insertion in the host lattice is probably indicated by distortion in lattice parameters and concomitant rise in microstrain and dislocation density. SEM images indicated homogenous and continuous growth of nanocrystallites. AFM images confirmed pillar like growth of crystallites along c-axis. Ru incorporation (1, 3, 5 and 7% at.) made film surface rougher, nevertheless roughness decreased with rise in Ru concentration. Ru incorporation at low concentrations significantly improved PEC response of films.     

Block Copolymer Nanostructures and Their Applications: A Review

Block copolymer nanostructures are smart, intelligent, and environment sensitive nanostructures designed to respond in a controlled manner to an external stimulus. Block copolymer nanostructures are being extensively utilized in pharmaceutical field, nanotechnology, and inforensics. Upon micellization, the hydrophobic core of block copolymer nanostructures region serves as a reservoir for hydrophobic medication, which can be loaded by chemical, physical, or electrostatic means. DNA combined with synthetic block copolymer nanostructure enhances the chemical and biological behaviors of biomacromolecule and at the same time completely suppress undesirable properties. Novel Nanoelectromechanical Systems/Microelectromechanical Systems (NEMS/MEMS) devices are being realized using block copolymer nanostructures and DNA combined with inorganic material nanoparticles and small organic moieties.     

Utilization of green reductant Thuja Orientalis for reduction of GO to RGO

It is well known that graphene (G), graphene oxide (GO) and reduced graphene oxides (RGO) are materials of today with immense application potentials. However, to realize the same large scale, reproducible, sustainable synthesis techniques such as greener methods which avoid utilization of toxic chemicals for synthesis, must be adopted. It is in this context, that here we report the reduction of GO to RGO by the extract of Thuja Orientalis (TO) seeds. As such, TO is a well-known bio-resource for medicinal and various other biotechnological applications as it contains Alpha Tocopherol, the major constituent of vitamin E. To the best of our knowledge, despite the wealth of literature, the current work makes a pioneering effort in applying TO seeds extract for reduction of GO to RGO. Thus, the reduction of GO, synthesized by the well-known modified Hummer's method to RGO by TO extract, is confirmed from the results obtained by ultra-violet visible (UV–Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) analysis, selected area electron diffraction (SAED), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), atomic force microscopy (AFM) and especially, gas chromatograph mass spectrometry (GCMS) techniques. Furthermore, the GCMS study is used to identify the compound Alpha Tocopherol responsible for reduction of GO to RGO. Based on current experimental evidences and literature views, the possible mechanism of reduction is suggested. Finally, the implications of present studies in the perspective of large scale, sustainable synthesis of RGO for various technological applications are discussed.     

Renewable energy education in Botswana: needs, status and proposed training programs

Lack of trained manpower for repair and maintenance of solar energy devices in Botswana has resulted in failure of devices, loss of revenue, and dwindling of consumer faith in solar technologies. The government of Botswana commissioned a study to assess the needs for trained manpower in New and Renewable Sources of Energy (NRSE) technologies, to identify the required training programs and their levels, and the facilities that need to be upgraded and/or created for the implementation of such training programs at the existing technical and educational institutions within the country. The paper presents the findings of the study, and the recommendations made. The study proposed seven training programs at progressively increasing skills and expertise levels that include two certificate courses in each of the solar water heating and photovoltaic technologies for maintenance personnel, a national craft certificate program in solar energy technologies, a higher diploma in energy technologies for supervisory personnel, and a short course for upper management personnel in decision-making positions in order to raise their skills in the procurement of equipment and services, and to provide overall effective leadership. A short course to upgrade the skills of the present maintenance personnel to alleviate the immediate problems is also proposed. Required upgrading of existing technical training facilities, the creation of new facilities and estimated budgetary requirements constitute some of the recommendations. The recommendations have gone through various channels of discussions, and have been accepted in principle. The report is currently under consideration for implementation by relevant government departments.     

Electrochemical loading of hydrogen in palladium capped samarium thin film: structural, electrical, and optical properties

A 50 nm samarium film capped with a 7 nm palladium overlayer switched from a metallic to semiconducting state during ex-situ hydrogen loading via electrochemical means at room temperature. The transition is accompanied by a change in transmittance measured during hydrogen loading and the associated optical appearance. The monitoring of working electrode (WE) potential, the transmittance and chi potential difference (Δχ) has been used to identify the phases present during hydrogen loading. Deloading of hydrogen has been studied in open circuit potential condition. Glancing angle X-ray diffraction (GAXRD) studies show that the rhombohedral structure of metallic samarium film (a₀=8.989 Å) changes to hexagonal structure of the SmH_3−δ film with average lattice parameters of a=3.775 Å and c=6.743 Å. A direct optical band gap of 2.9 eV has been obtained for SmH_3−δ film and 2.0 eV for SmH_{2 ± ε} film from reflectance and transmittance data. Removal of hydrogen from SmH_3−δ leads to the formation of localized states within the band whose signature is clearly seen in transmittance and Tauc’s plot curves of SmH_{2 ± ε} film. The Hall coefficient R_H measured as a function of hydrogen concentration, changes from a metal-like value −14.23×10^-10 m³/C to −1001.1×10⁻¹⁰ m³/C for SmH_3−δ films. On unloading hydrogen, the value of R_H changes to −3.56×10⁻¹⁰ m³/C at the dihydride composition.     

Synthesis and characterization of polypyrrole by cyclic voltammetry at different scan rate and its use in electrochemical reduction of the simulant of nerve agents

In this study, polypyrrole (pPy) was in-situ electrosynthesized on gold electrode surface using four different scan rate variations such as 5, 10, 25 and 50 mV/s with the help of cyclic voltammetry. Scanning electron microscopy (SEM) characterization revealed a scan rate dependent surface morphology for the pPy modified electrodes. The surface functional groups and elemental composition of the modified electrodes were deduced using Raman spectroscopy and energy dispersive X-ray spectroscopy (EDS), respectively. These pPy modified electrodes were utilized to study the electrochemical behavior of the nerve agents’ simulant dimethyl methyl phosphonate (DMMP) in aqueous medium. These modified electrodes exhibited electrochemical parameters with DMMP depending on the scan rate used for the in-situ synthesis of pPy conducting polymer.