Random vibration analysis of space flight hardware using NASTRAN

During liftoff and ascent flight phases, the Space Transportation System (STS) and payloads are exposed to the random acoustic environment produced by engine exhaust plumes and aerodynamic disturbances. The analysis of payloads for randomly fluctuating loads is usually carried out using the Miles' relationship. This approximation technique computes an equivalent load factor as a function of the natural frequency of the structure, the power spectral density of the excitation, and the magnification factor at resonance. Due to the assumptions inherent in Miles' equation, random load factors are often over-estimated by this approach. In such cases, the estimates can be refined using alternate techniques such as time domain simulations or frequency domain spectral analysis. Described here is the use of NASTRAN to compute more realistic random load factors through spectral analysis. The procedure is illustrated using Spacelab Life Sciences (SLS-1) payloads and certain unique features of this problem are described. The solutions are compared with Miles' results in order to establish trends at over or under prediction

Transient loads analysis for space flight applications

A significant part of the flight readiness verification process involves transient analysis of the coupled Shuttle-payload system to determine the low frequency transient loads. This paper describes a methodology for transient loads analysis and its implementation for the Spacelab Life Sciences Mission. The analysis is carried out using two major software tools - NASTRAN and an external FORTRAN code called EZTRAN. This approach is adopted to overcome some of the limitations of NASTRAN's standard transient analysis capabilities. The method uses Data Recovery Matrices (DRM) to improve computational efficiency. The mode acceleration method is fully implemented in the DRM formulation to recover accurate displacements, stresses, and forces. The advantages of the method are demonstrated through a numerical example

Growth, mortality and stock assessment of two perches moontail bull's eye Priacanthus hamrur (PerciformeslPricanthidae) and thomycheek grouper Epinephelus diacanthus (Perciformes/Serranidae) from Bombay waters

Based on the data collected from 1989-n the growth, mortality and stock assessment of P. hamrur and E. diacanthus were calculated. The von Bertalanffy's growth functions worked out for P. hamrur were as follows Lro=360 mm, K=O.64 per year and that of E. diacanthus were Lro=494 mm and K=O.59 per year. Based on these calculations the growth of P. hamrur at the end of I-IV years works out to be as 171,260, 308 and 334 mm. The length attained by E. diacanthus at the end of I-IV years of its life works out to 223, 345, 414 and 451 mm respectively. The mortality coefficients - Z, M and F were worked out 2.24,1.13 and 1.11 for P. hamrur. The same for E. diacanthus was calculated as 1.74, 1.1 and 0.64 respectively. Stock assessment study shows that there is no decline in the catch at the present rate of explOitation. However, even if the efforts are trebled, the increase in the catch will not be proportionate and returns are not remunerative

An innovative approach to manage prosumers in smart grid

Smart Grid (SG) achieves bidirectional energy and information flow between the energy user and the utility grid, allowing energy users not only to consume energy, but also to generate the energy and share with the utility grid or with other energy consumers. This type of energy user is called the "prosumer". The sustainability of the SG energy sharing process depends on its participating prosumers. Hence the prosumer management schemes are crucial within the energy sharing field. However, the existing literature on SG energy sharing has shown little attention on prosumer participation and management. The contribution of this paper is twofold. First we critically analyze the prosumer management schemes used by existing approaches and identify the open research issues. Second, we introduce a novel concept to manage the prosumers in the form of goal oriented virtual prosumer-communities and we discuss the aspects of prosumer-community formation, growth and overall management. The main significance of this approach is that the prosumer-communities facilitate the prosumers with similar interest to join together and increase the quantity of energy to be auctioned to the SG and accordingly increase the bargaining power in the energy market. In addition, the prosumer communities can attain more sustainable energy sharing process in long-term

Content quality assessment related frameworks for social media

The assessment of content quality (CQ) in social media adds a layer of complexity over traditional information quality assessment frameworks. Challenges arise in accurately evaluating the quality of content that has been created by users from different backgrounds, for different domains and consumed by users with different requirements. This paper presents a comprehensive review of 19 existing CQ assessment related frameworks for social media in addition to proposing directions for framework improvements

A Critical Review of Rukshana Karma in Clinical Practice

Acharya Charaka explained six unique treatment modalities which are called as Shadvidhopakramas. Rukshana is one among those Upakramas. The Word ‘Upakrama’ has several meaning like planning, beginning, remedy and preparation etc. here Upakrama refers to planning a suitable treatment modality and working to execute it. Shadvidhopakrama includes Langhana, Brimhana, Sthambhana, Rukshana, Snehana and Swedana. These can be broadly classified under two headings as Santarpana and Apatarpana. Santarpaniya Upakramas are Brimhana, Snehana and Sthambana, where as Apatarpaniya Upakramas are Langhana, Rukshana and Swedana. Out of these six types, Rukshana is of the same importance as others. The details of Rukshana will be dealt in this article

Real-time public group collaboration using IP multicast label filters

Internet based enterprise level collaboration tools enable organizations to make decisions faster and more accurately with less effort. However, these tools provide limited real-time group collaboration within and across organizations. Multicast protocols were developed to provide efficient group communication. This paper proposes a novel IP multicast network layer filter architecture that provides efficient and scalable real-time group collaboration between the required entities within an organization. This proposed network architecture uses a label filter mechanism to improve scalability and bandwidth for one-to-many and many-to-many real-time collaboration

Contactless digital tachometer using microcontroller

Tachometer is a device that used for counting or for the measuring purpose of the number of revolutions (that is the total number rotations made by the device in unit of measuring time) of an object in unit time. It is expressed in the unit of RPS or RPM, the model uses a set of infrared transducer receiver to count the RPM pulses, and the Arduino microcontroller is used for the implementation of the project. The individual pulses are counted by the microcontroller to give the final output of the RPM

FORMULATION, OPTIMIZATION AND EVALUATION OF FLOATING TABLETS CLARITHROMYCIN

Objective: The present aim of this study was to formulate, optimize and evaluation of floating tablets of Clarithromycin.Methods: Floating tablets of Clarithromycin were formulated using polymer HPMC K15M with sodium bicarbonate as gas generating agent by wet granulation method. A 32 factorial design were applied to systematically optimize the drug release profile. The amount of citric acid (X1) and concentration of polymer HPMC K15M (X2) was selected as independent variables. The drug release at 6 hours (Q6) and drug release at 12 hour (Q12), and diffusion exponent (n) was selected as dependent variables.Results: The results of factorial design indicated that low level of HPMC K15M favors the preparation of floating controlled release of Clarithromycin tablets. The tablets were evaluated for thickness, hardness, weight variation, floating lag time, total floating time, swelling index, drug content uniformity and in vitro drug release in 0.1N HCL (pH 1.2). The in vitro dissolution profiles of all the prepared Clarithromycin floating drug delivery system formulations was found to extend the drug release over a period of 10 to 12 hours and the drug release rate decreased with increase in polymer concentration.Conclusion: It can be concluded that the decreased in citric acid concentration in the formulation showed decreased in drug release, this is due to citric acid reaction with sodium bicarbonate resulting generation of carbon dioxide gas at a faster rate, increased rate of drug release. Increasing the concentration of HPMC K15M resulted in reduction of drug release

Wireless Sensor Networks: Challenges Ahead

The aim of this paper is to analyze the different Wireless Sensor Network (WSN) transport protocols byidentifying various experimental parameters in order to undertake a comparative evaluation. To build the groundwork, we first discuss the generic design for a transport protocol based on three key concepts; congestion control, reliability support and priority support. The basis of this design was developed by assessing several aspects of numerous transport protocols. However they all using different set of parameters and settings and hence it is difficult to benchmark one against the other. In this paper, we discuss the simulation settings like packet size, number of exploited sensors and their distribution in the field, buffer size, coverage area and power levels