Dark matter and stable bound states of primordial black holes

We present three reasons for the formation of gravitational bound states of primordial black holes,called holeums,in the early universe.Using Newtonian gravity and nonrelativistic quantum mechanics we find a purely quantum mechanical mass-dependant exclusion property for the nonoverlap of the constituent black holes in a holeum.This ensures that the holeum occupies space just like ordinary matter.A holeum emits only gravitational radiation whose spectrum is an exact analogue of that of a hydrogen atom. A part of this spectrum lies in the region accessible to the detectors being built.The holeums would form haloes around the galaxies and would be an important component of the dark matter in the universe today.They may also be the constituents of the invisible domain walls in the universe.Comment: 13 pages,2tables,for wider circulation,PD

Thermalization in one- plus two-body ensembles for dense interacting boson systems

Employing one plus two-body random matrix ensembles for bosons, temperature and entropy are calculated, using different definitions, as a function of the two-body interaction strength \lambda for a system with 10 bosons (m=10) in five single particle levels (N=5). It is found that in a region \lambda \sim \lambda_t, different definitions give essentially same values for temperature and entropy, thus defining a thermalization region. Also, (m,N) dependence of \lambda_t has been derived. It is seen that \lambda_t is much larger than the \lambda values where level fluctuations change from Poisson to GOE and strength functions change from Breit-Wigner to Gaussian.Comment: 7 pages, 4 figure

Spectral analysis of molecular resonances in erbium isotopes: Are they close to semi-Poisson?

We perform a thorough analysis of the spectral statistics of experimental molecular resonances, of bosonic erbium $^{166}$Er and $^{168}$Er isotopes, produced as a function of magnetic field($B$) by Frisch et al. [Nature 507, (2014) 475], utilizing some recently derived surmises which interpolate between Poisson and GOE and without unfolding. Supplementing this with an analysis using unfolded spectrum, it is shown that the resonances are close to semi-Poisson distribution. There is an earlier claim of missing resonances by Molina et al. [Phys. Rev. E 92, (2015) 042906]. These two interpretations can be tested by more precise measurements in future experiments.Comment: 7 pages, 6 figure

Development and evaluation of plastic based solar still for production of distilled water

Solar still was developed and evaluated at Department of Renewable Energy Engineering, College of Agricultural Engineering and Technology, Dediapada. The average yield of distilled water in developed solar still varied from 1055-1498 ml/m 2 -day during winter and summer where as in already developed still varied 1350 to 1550 ml /m 2 day . Thermal efficiency of developed solar still was found as 20 per cent .The physicochemical analysis was carried out to examine the effect of distillation on tap water. A drastic reduction in the TDS, Chlorides, Calcium hardness and magnesium hardness, dissolved silica was observed through solar distillation. The payback period of the unit was only 6 months and after that period the unit produced net profit. The manufacturing cost of this developed solar still was only Rs. 1640/- which was totally manufactured in plastic material so no any corrosive material came in contact for changing the property of distilled water as output. Cleaning of solar still could be easily carried out by just removing the w shape dome of developed device which cannot be possible in available solar still in market

Design, development and demonstration of a Shallow solar tunnel dryer for non-electrified areas

This paper presents the design, construction and performance evaluation of a shallow solar tunnel dryer for agro and industrial products. In the shallow solar tunnel dryer, there are three separate units viz.: an air heating unit, drying unit and air diversion unit. Total area of the solar tunnel dryer was 21 m². The heated air from a separate solar air heating zone is passed through a product bed, and at the same time, the drying tunnel bed absorbs solar energy directly through the transparent UV stabilized plastic sheet used as covering material. This dryer was not required any external sources of the power to operate the electrical fan. The system was designed to operate at a temperature of 50 to 60oC. The system was installed at the institute and initial testing was conducted. After that the system was also demonstrated at the actual potential user’s site. The results obtained during the test period revealed that the temperatures inside the tunnel drying zone and solar air heating zone were much higher than the ambient air temperature during most hours of the day-light. The temperature rise inside the drying tunnel was up to 67.4°C at peak hour’s period (noon). The drying rat e and thermal efficiency of the collector were 1.73 kg/h and 26.0% respectively. The high outlet temperature indicated the scope of loading the dryer further