Further Studies of F-Region at Allahabad

Result of measurement of virtual height of the F-region carried out (mostly at night) during 1937-38 session on several wave frequencies are described. It is found that the nature of the equivalent height change varies in a marked manner from day to day. Sometimes the virtual height shows three maxima during a single night. A good correlation has been found to exist between the hour of occurrence of minimum virtual height of the F-region and the hour at which the barometer at ground level leads maximum pressure. Occasionally echoes from regions above the normal F-layer have been obtained, Occurrence of complex echoes is found to be associated with variation of one or other of the terrestrial magnetic elements. It is seen that contrary to the results obtained by many investigators the F-region exists till about 10 o'clock at nigh

Design optimization in geometry of seismic mass for MEMS based cantilever type piezoelectric energy harvester for motor vibrations

Piezoelectric energy harvesters are suitable for vibration energy harvesting due to simple design, operation and fabrication in MEMS technology. Cantilever structures fixed from one end and seismic mass at the other must tune to different resonance frequency to ensure wideband frequency operation. Adequate width to length ratio of cantilever is required to avoid curling of cantilevers (bending). Effect of increase in width of the cantilever structure on resonance frequency has been investigated and also compared analytically in this paper. An optimized design has been proposed which compensates for the increase in resonance frequency due to increase in width by changing the geometry of the seismic mass. With the change in geometry of seismic mass a shift in center of mass has been achieved towards the free end of the cantilever which reduces the resonance frequency which is desirable. The design optimization of seismic mass reported in this paper reduces the resonance frequency by 4.27 % which is appreciated as it is required to harvest ambient vibrations having low frequency

Water poverty in the northeastern hill region (India): potential alleviation through multiple-use water systems: cross-learnings from Nepal Hills

Water poverty index / Construction / Multiple use / Water storage / Farming systems / Villages / Social aspects / Drip irrigation / India / Nepal / Nagaland / Mon district / Lampong Sheanghah

Fixed Points of Weakly Compatible Mappings Using Common (E.A) Like property

The aim of this paper is to prove common fixed point theorems in Menger spaces using implicit relation and common (E.A) like property. An example is derived to support our main result. We extend our result to four finite families of self mappings. As an application of our main result, we prove an integral type common fixed point theorem satisfying ψ-contraction condition in Menger space. Our results improve some recent results in Menger spaces

Bianchi type-II cosmological model: some remarks

Within the framework of Bianchi type-II (BII) cosmological model the behavior of matter distribution has been considered. It is shown that the non-zero off-diagonal component of Einstein tensor implies some severe restriction on the choice of matter distribution. In particular for a locally rotationally symmetric Bianchi type-II (LRS BII) space-time it is proved that the matter distribution should be strictly isotropic if the corresponding matter field possesses only non-zero diagonal components of the energy-momentum tensor.Comment: 3 page

A coupled fixed point theorem in fuzzy metric space satisfying φ-contractive condition

The intent of this paper is to prove a coupled fixed point theorem for two pairs of compatible and subsequentially continuous (alternately subcompatible and reciprocally continuous) mappings, satisfyingϕ-contractive conditions in a fuzzy metric space. We also furnish some illustrative examples to support our results

Performance of pilot-scale microbial fuel cells treating wastewater with associated bioenergy production in the Caribbean context

Microbial fuel cell (MFC) technology represents a form of renewable energy that generates bioelectricity from what would otherwise be considered a waste stream. MFCs may be ideally suited to the small island developing state (SIDS) context, such as Trinidad and Tobago where seawater as the main electrolyte is readily available and economical renewable and sustainable electricity is also deemed a priority. Hence this project tested two identical laboratory-scaled MFC systems that were specifically designed and developed for the Caribbean regional context. They consisted of two separate chambers, an anaerobic anodic chamber inoculated with wastewater and an aerobic cathodic chamber separated by a proton exchange membrane. Domestic wastewater from two various wastewater treatment plants inflow (after screening) was placed into the anodic chamber, and seawater from the Atlantic Ocean and Gulf of Paria placed into the cathodic chambers respectively with the bacteria present in the wastewater attaching to the anode. Experimental results demonstrated that the bacterial degradation of the wastewaters as substrate induced an electron flow through the electrodes producing bioelectricity whilst simultaneously reducing the organic matter as biochemical oxygen demand and chemical oxygen demand by 30 to 75%. The average bioenergy output for both systems was 84 mW/m² and 96 mW/m² respectively. This study demonstrated the potential for simultaneous bioenergy production and wastewater treatment in the SIDS context

Observation of semiannual and annual oscillation in equatorial middle atmospheric long term temperature pattern

Extensive measurement of middle atmospheric temperature with the help of lidar data of more than 10 years (1998–2008) and TIMED/SABER data of 7 years (2002–2008), has been carried out from a low latitude station, Gadanki, India (13.5° N, 79.2° E), which exhibits the presence of semiannual oscillation (SAO) and annual oscillation (AnO). The AnO component is stronger in the mesospheric region (80–90 km) and the SAO is dominant at stratospheric altitudes (30–50 km). Overall, the AnO possesses higher amplitude ~6–7 K, and the SAO shows less amplitude ~1–2 K. The AnO present at 90 km finds crest near summer solstice, and the same at 80 km shows peak near winter solstice with a downward progression speed ~1.7 km/month. The SAO propagates downward with an average phase speed ~9 km/month and phase maximizes around equinox and solstice at 50 and 30 km, respectively. The observed SAO has also shown seasonal asymmetry in peaks