First & Second Law Analysis of Solar Air Heater

In this paper, thermodynamic analysis is performed for different cases of artificial roughness surface on the absorber plates of solar air heater duct. This analysis has been performed by using the correlations for heat transfer coefficient and friction factor developed experimentally for different type of roughness within the investigated range of operating and system parameters. The comparison has been made for different types of roughness on the basis of first law analysis (effective efficiency) and second law analysis (entropy, irreversibility distribution ratio and entropy generation number)

Energy Constrained Dominating Set for Clustering in Wireless Sensor Networks

Using partitioning in wireless sensor networks to create clusters for routing, data management, and other protocols has been proven as a way to ensure scalability and to deal with sensor network shortcomings such as limited communication ranges and energy. Choosing a cluster head within each cluster is important because cluster heads use additional energy for their responsibilities and that burden needs to be carefully passed around. Many existing protocols either choose cluster heads randomly or use nodes with the highest remaining energy. We introduce the energy constrained minimum dominating set (ECDS) to model the problem of optimally choosing cluster heads with energy constraints. We propose a distributed algorithm for the constrained dominating set which runs in O(log n log Δ) rounds with high probability. We experimentally show that the distributed algorithm performs well in terms of energy usage, node lifetime, and clustering time and, thus, is very suitable for wireless sensor networks

Vision screening among hearing-impaired school children in Biratnagar, Nepal

Background: The prevalence of hearing impairment in Nepal is 16.5%, affecting approximately 2.71 million people. Deaf children are visually dependent, and even a mild refractive error may cause visual discomfort. The goal of this study was to determine the need for vision screenings in schools for the hearing impaired in Biratnagar, Nepal. Methods: A cross-sectional study was conducted with permission from Birat Deaf Secondary School, Biratnagar, Nepal. A total of 130 hearing-impaired students were examined. Non-invasive, comprehensive optometric examinations were performed to detect visual disorders. When a more detailed evaluation was needed, the students were referred to the Pediatric Ophthalmology Department, Biratnagar Eye Hospital Biratnagar, Nepal. Results: Of the 130 hearing-impaired students, 58 (44.6%) were male and 72 (55.4%) were female. The mean ± standard deviation of age was 16.03 ± 3.8 years (range 6–25 years). Twenty-one (16.1%) students had refractive errors: 13 (10%) had myopia, 7 (5.4%) had hyperopia, and 1 (0.8%) had anisometropia. In the cover test, 88 (67.7%) had orthophoria, 19 (14.6%) had exophoria, 11 (8.5%) had esophoria, 5 (3.85%) had exotropia, and 3 (2.3%) had esotropia. Cover tests were not performed in 4 (3.1%) students, as they were unable to fixate due to nystagmus or decreased vision. On ocular examination, 20 (15.3%) students had anterior segment abnormalities, including lid abnormality, conjunctivitis, Bitot’s spots, pterygium, corneal opacity, and lenticular opacity. Posterior segment or retinal abnormalities were found in four students with one having Usher syndrome. Color vision defects, nystagmus, and amblyopia were found in 8 (6.1%), 2 (1.5 %), and 1 (0.8%), respectively. Conclusions: The findings of the present study reflect the need of periodic vision screenings in schools for the hearing impaired in Nepal. These children are at a high risk of vision impairment. How to cite this article: Sah SK, Thakur R, Adhikari PR. Vision screening among hearing-impaired school children in Biratnagar, Nepal. Med Hypothesis Discov Innov Optom. 2021 Spring; 2(1): 36-40. DOI: https://doi.org/10.51329/mehdioptometry123 &nbsp

Formulation and Evaluation of Antimicrobial Potential of Glycerosomes Containing Allium sativum, Zingiber officinale Extracts

The aim of the present investigation is to evaluate the antimicrobial potential of A. sativum and Z. officinalis extracts mediated glycerosomes formulation by thin film of lipid hydration method.  The water content present in the A. sativum and Z. officinale was 42.3 and 27.2 % respectively. The yield of A. sativum and Z. officinale extract using ethanol as solvent through the Soxhlation process was found to be 4.7 ± 1.05 and 12.7 ± 1.108 % respectively. The crude drug of A. sativum and Z. officinale showed foreign organic was found to be 0.2 and 0.21 % and volatile oil was found to be 1.8 and 2.4 % only.  The ash study revealed that total, acid-insoluble, water-soluble, and sulfated ash values were for the crude drugs of A. sativum and Z. officinale. The ethanol extracts showed maximum extractive yield. The phytochemicals detected in A. sativum bulb ethanol extract are Alkaloids, Carbohydrates, Cardiac glycosides, Phenols, Sterols, Triterpenoids, Saponins, Flavonoids, and Fixed oils and in Z. officinale rhizome ethanol extract are Alkaloids, Carbohydrates, Cardiac glycosides, Anthraquinone glycosides, Proteins and Amino acids, Triterpenoids, Saponins, Flavonoid, and Fixed oils. The prepared glycerosome was spherical with a slightly irregular shape.  The negative potential of glycerosomes demonstrates the greater stability of the vesicular dispersion.  The ASEE glycerosome formulations (F1 and F2) exhibited better antibacterial activity and greater antifungal activity against the gram-negative bacteria in comparison with the ZOEE glycerosome formulations (F3 and F4).   The present research work strongly concluded that the A. sativum and Z. officinale and their glycerosome formulations are good candidate drugs and formulations for the safe and effective treatment of microbial infection

Use of artificial roughness to enhance heat transfer in solar air heaters – a review

Improvement in the thermo hydraulic performance of a solar air heater can be done by enhancing the heat transfer. In general, heat transfer enhancement techniques are divided into two groups: active and passive techniques. Providing an artificial roughness on a heat transferring surface is an effective passive heat transfer technique to enhance the rate of heat transfer to fluid flow. In this paper, reviews of various artificial roughness elements used as passive heat transfer techniques, in order to improve thermo hydraulic performance of a solar air heater, is done. The objective of this paper is to review various studies, in which different artificial roughness elements are used to enhance the heat transfer rate with little penalty of friction. Correlations developed by various researchers with the help of experimental results for heat transfer and friction factor for solar air heater ducts by taking different roughened surfaces geometries are given in tabular form. These correlations are used to predict the thermo hydraulic performance of solar air heaters having roughened ducts. The objective is to provide a detailed review on heat transfer enhancement by using an artificial roughness technique. This paper will be very helpful for the researchers who are researching new artificial roughness for solar air heater ducts to enhance the heat transfer rate and comparing with artificial roughness already studied by various researchers

Use of artificial roughness to enhance heat transfer in solar air heaters – a review

Improvement in the thermo hydraulic performance of a solar air heater can be done by enhancing the heat transfer. In general, heat transfer enhancement techniques are divided into two groups: active and passive techniques. Providing an artificial roughness on a heat transferring surface is an effective passive heat transfer technique to enhance the rate of heat transfer to fluid flow. In this paper, reviews of various artificial roughness elements used as passive heat transfer techniques, in order to improve thermo hydraulic performance of a solar air heater, is done. The objective of this paper is to review various studies, in which different artificial roughness elements are used to enhance the heat transfer rate with little penalty of friction. Correlations developed by various researchers with the help of experimental results for heat transfer and friction factor for solar air heater ducts by taking different roughened surfaces geometries are given in tabular form. These correlations are used to predict the thermo hydraulic performance of solar air heaters having roughened ducts. The objective is to provide a detailed review on heat transfer enhancement by using an artificial roughness technique. This paper will be very helpful for the researchers who are researching new artificial roughness for solar air heater ducts to enhance the heat transfer rate and comparing with artificial roughness already studied by various researchers

Giant pressure sensitivity in piezo/ferro-electric ceramics

We report the fabrication of single-phase polycrystalline Pb0.85Bi0.10(Zr0.52Ti0.48)O-3 (PBiZT) ceramic which shows large polarization, i.e., similar to 40 mu C cm(-2) and piezoelectric coefficients similar to 130 pC N-1 and giant linear change in capacitive reactance and dielectric properties with increasing and decreasing pressure in the range of 1 kHz to 5 MHz. Nearly 70% change in dielectric constant and 56% change in capacitive reactance were obtained in the pressure range of 20-200 MPa, which makes it suitable for applications as a capacitive pressure sensor/gauge. The sensitivity of the device is calculated as 0.66 MPa-1 and 18.2 MPa-1 at 1 MHz and 5 MHz, respectively, which is the highest ever reported value so far for any bulk polycrystalline ceramic. The compressive stress of the device was tested according to the standard test method as a function of linear and volumetric strain, which yields the Young's modulus, Bulk modulus, and Poisson's ratio of the device. These values were further utilized to calculate actual stress in the sample and energy density using ANSYS software, which indicates at least four orders smaller pressure in the sample compared to the applied pressure

Impact of elevated carbon dioxide and temperature on wheat production under sub temperate climate in north western Himalayas, India

Wheat is the second most important cereal crop and plays a key role in food and nutritional security. The study examines the impact of elevated carbon dioxide and temperature under limited irrigations on wheat crop using crop growth simulation models under sub temperate climate. The Info Crop model was validated using the historical data generated by the research trials of All India Coordinated Research Improvement Project at Palampur, Himachal Pradesh. The model was run for 20 years from 1991 to 2010 for Palampur weather station. The results revealed 3.6 to 4.0 percent and 1.7 to 7.5 percent increase in simulated crop yield with 420 and 470 ppm CO2 respectively. The elevated maximum and minimum temperature by 1 and 20C with 370 ppm carbon dioxide reduced the anthesis period by 5-7 and 9-11 days respectively over the sowing window of November 15th to December 30th. Similarly, days to maturity also reduced by 4-5 and 7-8 days with 1 and 20C rise in temperature respectively. The simulated crop yield showed increase by 17.9 to 63.0 and 33.2 to 133.4 percent with 1 and 20C rise in temperature at 370 ppm CO2 under limited irrigations. The simulated grain yield at 420 ppm CO2 showed an increase of 23 to 69.7 percent with 10C and 39.5 to 123.5 percent with 20C whereas at 470 ppm CO2 level the increase was 27.9 to 76.1 at 10C and 46.4 to 133.0 percent with 20C rise in maximum and minimum temperatures respectively. Hence, simulated results of elevated temperature and CO2 levels proved to be beneficial in rabi wheat with adaptations strategy of limited irrigations under sub temperate climate of North Western Himalaya

Generalized Neuron Based Secure Media Access Control Protocol for Wireless Sensor Networks

Security plays a pivotal role in most applications of wireless sensor networks. It is common to find inadequately secure networks confined only to controlled environments. The issue of security in wireless sensor networks is a hot research topic for over a decade. This paper presents a compact generalized neuron (GN) based medium access protocol that renders a CSMA/CD network secure against denial-of-service attacks launched by adversaries. The GN enhances the security by constantly monitoring multiple parameters that reflect the possibility that an attack is launched by an adversary. Particle swarm optimization, a popular bio-inspired evolutionary-like optimization algorithm is used for training the GN. The wireless sensor network is simulated using Vanderbilt Prowler, a probabilistic wireless network simulator. Simulation results show that the choice of threshold suspicion parameter impacts on the tradeoff between network effectiveness and lifetime