Are Radio Pulsars Strange Stars ?

A remarkably precise observational relation for pulse core component widths of radio pulsars is used to derive stringent limits on pulsar radii, strongly indicating that pulsars are strange stars rather than neutron stars. This is achieved by inclusion of general relativistic effects due to the pulsar mass on the size of the emission region needed to explain the observed pulse widths, which constrain the pulsar masses to be less than 2.5 Solar masses and radii to be smaller than 10.5 km.Comment: v.2 : 12 pages including 3 figures and 2 tables, LaTex, uses epsfig. This version has one extra figure, few lines of new text and typos fixe

Changes in Electrocardiogram Among Temporary Residents at High Altitude

A prospective study was conducted on young healthy men who were residents of plains and stayed at high altitude for 24 months-the first 12 months at an altitude of 4,200 metres and subsequent 12 months at 3,600 metres.Their ECGs were recorded in the plains before departure for high altitude and after 3, 6, 11, 18 and 23 months of stay at high altitude. After their return tothe plains further ECG examinations were carried out after 1, 3 and 6 months of return. ECG changes suggestive of right ventricular hypertrophy were present in a substantial number of individuals after three months of arrival and they persisted during their stay at high altitude. The ECG changes reversed completely in majority of individuals within one month of return to plains. These changes are considered to be due to hypoxia and are reversible

Analysis of navigation performance for the Earth Observing System (EOS) using the TDRSS Onboard Navigation System (TONS)

Use of the Tracking and Data Relay Satellite System (TDRSS) Onboard Navigation System (TONS) was proposed as an alternative to the Global Positioning System (GPS) for supporting the Earth Observing System (EOS) mission. The results are presented of EOS navigation performance evaluation with respect to TONS based orbit, time, and frequency determination (OD/TD/FD). Two TONS modes are considered: one uses scheduled TDRSS forward link service to derive one way Doppler tracking data for OD/FD support (TONS-I); the other uses an unscheduled navigation beacon service (proposed for Advanced TDRSS) to obtain pseudorange and Doppler data for OD/TD/FD support (TONS-II). Key objectives of the analysis were to evaluate nominal performance and potential sensitivities, such as suboptimal tracking geometry, tracking contact scheduling, and modeling parameter selection. OD/TD/FD performance predictions are presented based on covariance and simulation analyses. EOS navigation scenarios and the contributions of principal error sources impacting performance are also described. The results indicate that a TONS mode can be configured to meet current and proposed EOS position accuracy requirements of 100 and 50 m, respectively

Landmine Detection Technologies to TraceExplosive Vapour Detection Techniques

Large quantity of explosive is manufactured worldwide for use in various types of ammunition,arms, and mines, and used in armed conflicts. During manufacturing and usage of the explosiveequipment, some of the explosive residues are released into the environment in the form ofcontaminated effluents, unburnt explosives fumes and vapours. Limited but uncontrolledcontinuous release of trace vapours also takes place when explosive-laden landmines are deployedin the field. One of the major technological challenges in post-war scenario worldwide is thedetection of landmines using these trace vapour signatures and neutralising them safely.  Differenttypes of explosives are utilised as the main charge in antipersonnel and antitank landmines. Inthis paper, an effort has been made to review the techniques so far available based on explosivevapour detection especially to detect the landmines. A comprehensive compilation of relevantinformation on the techniques is presented, and their maturity levels, shortcomings, and difficultiesfaced are highlighted

Effect of Surfactants on the Fluorescence Intensity of 9,10-Diphenylanthracene

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Workplace Air Quality at Explosive Material Manufacturing and Handling Units

Worldwide, large quantities of explosives are manufactured for use in various types ofammunitions, arms, and mines. Toxic pollutants in the workplaces of three major activities, viz.,explosive and solid propellant preparation facility, solid propellant shell assembling facility, andsolid propellant shell proof firing facility, were studied. The suspended particulate matter (SPM)concentration in grinding room (13.9 mg/m3) and sieving room (19.3 mg/m3) of solid propellantpreparation facility was observed to be two to threefold higher than the permissible limit. TheSPM in the dentex preparation section was found to be significantly high (10.8 mg/m3). Thepersonal exposure was fourfold higher (21 mg/m3) than the permissible limit. It was emerged thatconcentration of particulate is a major concern in all the processing sections. Since the chemicalnature of these particulates is expected to be more toxic in nature, it requires greater attention.At firing point, carbon monoxide appeared to be a major concern

Case History of a Partially Underground Power House

In the normal rock conditions, conventional type surface power houses have been built, whereas in structurally sound rock with sufficient rock cover, underground power houses have been attempted in India. The geological uncertainties plays major role in deciding the type of power house at a particular site. While in the surface type conventional power house huge excavation and concreting are involved, the access to the power house involves major work in the case of underground power house. There are very little examples when semi underground type of power houses have been attempted in India. The Mahi power house-II of Rajasthan is the sole attempt of shaft type of power house after the successful completion of small Giri power house in Himachal Pradesh. This paper presents the case study of this shaft type semi underground power house. Important features about its layout, design and construction have been discussed here

Construction of Hydel Power House in Weak Rocks

Geological uncertainties have always played an important role in planning of a hydel power house. This paper presents case study of a power house which was subjected to major revisions in its planning due to inherent instabilities in rock slopes. Initially the power house was planned with service bay and other facilities on its left hand side, but the weak and instable slopes and sliding of large rock masses necessitated its thorough revision by bringing service bay and other facilities to its right hand side along with addition of many new features and flattening of slopes. There were many alternatives under consideration and final selection was based on techno-economic balance of the project

Comparative Study of Ground Water Quality of Udaipur and its Surrounding Areas

Ground water is considered one of the country's most important natural resources. It's responsible for approximately 40% of the water utilized for all other purposes except for the generation of hydropower and the cooling of electric power plants. Interestingly, it's resources that are commonly utilized and have a significant impact on the country's health and economy. Ground water is the natural gift to humanity, it is valued at around 210 billion m3 and includes the volume of recharge as well as the volume of water that evaporates and falls to the earth. One third of the water is used for irrigation, the remaining two-thirds are domesticated and industrially utilized. The majority of the water is re-circulated into rivers. Today, the rapid rate of development, increased industrialization, and population density have all contributed to an increased burden on water resources. The process of groundwater pollution is different from the pollution of surface water; the resource is imperceptible and recovery is difficult at the current state of technology (MacDonald and Kavanaugh 1994). As part of the international effort to understand the functions, structures, and processes within the CZ, a variety of investigations have been conducted that contribute to our understanding of the flow and evolution of groundwater (Sawyer et al. 2016; Goldhaber et al. 2014). Water pollutants in groundwater are typically odorless and colorless. Additionally, the adverse effects of polluted groundwater on human health are long-term and are extremely difficult to recognize (Chakraborti et al. 2015). Around one third of the world's population is  dependent on groundwater for drinking water ( International The association of hydrogeologists is dedicated to promoting the study of water-related issues. Groundwater is water that is particularly significant in arid and semiarid regions. where precipitation and surface water are confined (Li et al.2017a)