80 research outputs found
Seasonal march of surface pressure gradients across India and the southwest monsoon
No full textIt is well known that the seasonal weather features of Indian sub-continent are associated with corresponding changes in the pressure gradients across the country
Concentration in Knowledge Output: A case of Economics Journals
No full textThis paper assesses the degree of author concentration in seven economics journals, which were published in India during 1990-2002. To measure the degree of author concentration, Lotka's Law was used. Moreover, we also make an exploratory analysis of the geographic, economics subfield and institutional concentration in 704 economics journals. An important finding of this paper is that specialized journals in the sample report the highest degree of author concentration. This result is quite similar to the findings by Cox and Chung (1991). Furthermore, there are several instances showing that the journals lean towards certain norms; this may affect the flow of innovative ideas into economics. We conclude that a knowledge activity, involving the high degree of concentration and a biased publication process, may affect the flow of new ideas into the discipline.Concentration, Lotka's Law
Optimization of Solar Sailcraft Trajectory for a Comet Sample Return Mission
No full textComets, the sporadic visitors from the outer edges of the Solar System, are considered to hold the key for understanding the formation of planets and the origin of life on Earth. Having spent the majority of time away from the radiative environment of the inner Solar System, the chemistry of the comets has remained unaltered, making them the pristine samples of the matter from the ancient Solar nebula. A mission to bring cometary particles back to Earth enables the examination of the materials in well equipped laboratories and saves the mass of the instruments to be carried on board. As conventional propulsion methods require a large quantity of propellant for this type of mission, the feasibility of using the novel propulsion technique of solar sailing is explored in this thesis. In order to return the comet samples to Earth within a reasonable time period, the orbit transfer is considered as an optimal control problem with constraints placed on the sailcraft’s position and velocity. The Differential Evolution (DE) algorithm was used to search for time-optimal trajectories that minimize the approach distance and the relative velocity with respect to the comet during sample collection. The optimal trajectory obtained predicts the solar sailcraft to reach the comet, collect the samples and return back to Earth in 6.8 years. The time of arrival at the comet was found to match with the comet's perihelion passage, enabling effective sample collection. The outcome of the trajectory analysis, thus successfully demonstrates the applicability of solar sailing to comet sample return missions in the near future.Aerospace Engineering | Astrodynamics & Space Mission
Systematic mask synthesis for surface micromachined microelectromechanical systems
No full textIn the context of designing surface-micromachined microelectromechanical systems (MEMS), there does not appear to be systematic means, with the exception of parametrized layout models, to generate the mask data after the geometric model of a MEMS device is refined through behavioral simulations. This paper focuses on automatically generating masks, given a geometric model of the MEMS device and the process sequence (referred to here as the inverse problem). This necessitates a systematic solution of the forward problem, which involves automatically generating a geometric model of the MEMS device given the masks. A systematic and implementation-independent framework for the geometric modeling of MEMS is presented in order to solve the forward and inverse problems for general surface-micromachined devices. In particular, the geometric problem of mask synthesis is reduced to a system of linear equations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49041/2/jm3616.pd
Cloning and molecular analysis of the human citrate synthase gene
No full text The nucleotide sequence encoding the citrate synthase (CS) gene was determined from the sequencing of the CS cDNA isolated from a human heart cDNA library. The primary sequence of CS deduced from its nucleotide sequence reveals a highly conserved, albeit slightly larger, protein of 466 amino acids, with 95% homology to its pig homologue. The data also indicate that the human genomic CS gene contains no introns, and confirms the location of the human CS gene on chromosome 12.Key words: human, citrate synthase, Krebs' cycle. </jats:p
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