Reliability growth models for NASA applications

The objective of any reliability growth study is prediction of reliability at some future instant. Another objective is statistical inference, estimation of reliability for reliability demonstration. A cause of concern for the development engineer and management is that reliability demands an excessive number of tests for reliability demonstration. For example, the Space Transportation Main Engine (STME) program requirements call for .99 reliability at 90 pct. confidence for demonstration. This requires running 230 tests with zero failure if a classical binomial model is used. It is therefore also an objective to explore the reliability growth models for reliability demonstration and tracking and their applicability to NASA programs. A reliability growth model is an analytical tool used to monitor the reliability progress during the development program and to establish a test plan to demonstrate an acceptable system reliability

Reliability evaluation methodology for NASA applications

Liquid rocket engine technology has been characterized by the development of complex systems containing large number of subsystems, components, and parts. The trend to even larger and more complex system is continuing. The liquid rocket engineers have been focusing mainly on performance driven designs to increase payload delivery of a launch vehicle for a given mission. In otherwords, although the failure of a single inexpensive part or component may cause the failure of the system, reliability in general has not been considered as one of the system parameters like cost or performance. Up till now, quantification of reliability has not been a consideration during system design and development in the liquid rocket industry. Engineers and managers have long been aware of the fact that the reliability of the system increases during development, but no serious attempts have been made to quantify reliability. As a result, a method to quantify reliability during design and development is needed. This includes application of probabilistic models which utilize both engineering analysis and test data. Classical methods require the use of operating data for reliability demonstration. In contrast, the method described in this paper is based on similarity, analysis, and testing combined with Bayesian statistical analysis

Olfactory Neuroblastoma: Diagnostic Difficulty

Olfactory neuroblastoma is an uncommon malignant tumor of sinonasal tract arising from the olfactory neuro epithelium. The olfactory neuroblastomas presenting with divergent histomorphologies like, epithelial appearance of cells, lacking a neuro fibrillary background and absence of rosettes are difficult to diagnose. Such cases require immunohistochemistry to establish the diagnosis. We describe the clinical features, pathological and immunohistochemical findings of grade IV Olfactory neuroblastoma in a 57 year old ma

Plastic to Petrol

Perinjanam is a coastal village in Thrissur district in the state of Kerala, India. It is one of the smallest villages in Kerala. Perinjanam Panchayath has been recognized as the first Panchayath in India with ‘ISO 9001 2015’ certification. National Accreditation Board of Certification Body (NABCB) has conducted valuation in two steps and was found that the Panchayath has fulfilled the criteria suggested by Quality Council of India. The Science Centre was established in 2006 under the Charitable Society Act with an aim to undertake scientific experiments. Several Teachers and students are undertaking science related activities in 5 buildings spread over 70 cents of land of Kodungalloor Municipality. Mr. V. S. Sreejith, is the Director of Science Centre, has designed a plant and the perinjanam Panchayath has developed the prototype of a pyrolysis plant in which plastic waste is burnt and distilled to make petrol and other by products. This is a part of its endevour to find a low-cost and pollution free technology for processing non biodegradable waste

Molluscan Taxonomy

The molluscs belong to the large and diverse phylum Mollusca, which includes a variety of familiar animals well-known as decorative shells or as seafood. These range from tiny snails, clams, and abalone to larger organisms such as squid, cuttlefish and the octopus. These molluscs occupy a variety of habitats ranging from mountain forests, freshwater to more than 10 km depth in the sea. They range in size from less than 1 mm to more than 15 m (for example the giant squid) and their population density may exceed 40,000/m2 in some areas. In the tropical marine environment, molluscs occupy every trophic level, from primary producers to top carnivores

Empirical Determination of Threshold Partial Wave Amplitudes in pp→ppωp p \to p p \omega

Using the model independent irreducible tensor approach to $\omega$ production in $pp$ collisions, we show theoretically that, it is advantageous to measure experimentally the polarization of $\omega$, in addition to the proposed experimental study employing a polarized beam and a polarized target.Comment: 6 pages, 1 Table, Latex-2