30 research outputs found
An inverse model to determine the heat transfer coefficient and its evolution with time during solidification of light alloys
Infra-red probes linked to pyrometric chains and thermocouple arrays have been used to accurately determine both casting and die surface temperatures during the solidification of an aluminium A380 alloy and the magnesium alloy AZ91D. An inverse model was then used to accurately determine the heat flux densities and interfacial heat transfer coefficients and the rapid evolution of these values with time during high pressure die casting of these alloys
A 6.7 KBPS vector sum excited linear prediction on TMS320C54X digital signal processor
In this paper, a 6.7-kbps vector sum excited linear prediction (VSELP) coder with less computational complexity is presented. A very efficient VSELP codebook with nine basis vectors and a heuristic K-selection method (to reduce the search space and complexity) is constructed to obtain the stochastic codebook vector. The nine basis vectors are obtained by optimizing a set of randomly generated basis vectors. During the optimization process, we have trained the basis vectors to give the system apriori knowledge of the characteristics of the input. The coder is implemented on a TMS320C541 digital signal processor. The performance is evaluated by testing the 6.7-kbps VSELP coder with different test speech data taken from different speakers. The quality of the coder is estimated by comparing the performance of the 6.7-kbps VSELP coder with an 8-kbps VSELP speech coder based on the IS-54 standards
Separation of bimodal high density polyethylene using multidimensional high temperature liquid chromatography
High-temperature two-dimensional liquid chromatography (HT 2D-LC) using HT-HPLC as first dimension and HT-SEC as second dimension holds enormous potential to investigate the distribution according to molar mass and chemical composition of bimodal high density polyethylene (BiHDPE), as it avoids drawbacks of crystallization-based techniques. In this study, we have stepwise optimized the chromatographic parameters of 1D, comprising gradient slope and temperature, using model homo- and copolymers of ethylene with the aim to minimize the impact of molar mass on the compositional separation. Then the HT-HPLC was hyphenated to HT-SEC and optimum conditions for the volume of the sample transfer loop were probed with regard to the resolution of BiHDPE into the individual constituents HDPE and LLDPE. A particular important aspect was the use of infrared (IR) detection, and the demands it puts on the chromatographic aspects: We have shown that IR detection can be successfully applied in HT 2D-LC of BiHDPE, which is broadly distributed with regard to short chain branching and molar mass, only when the separation in 2D is optimized with regard to chromatographic resolution. As final result a bimodality is evident in the contour and the 3D surface plots as well as in both HPLC and SEC projections generated from HT 2D-LC
Private Agricultural Research
This chapter serves to assess the quantity and impact of private agricultural research in developing countries, alongside the policies which affect that research. To provide context, an outline of the history, size and structure of private research presents data on research expenditures by region, by agency, by crop and by industrial sector. Evidence on research inputs reflects not only the importance of private research, but also the wide national and regional differences in both inputs and implementation of programs. Research output and intellectual property rights (IPR) protection are also strikingly different across time and space, as seen in data on agricultural IPRs by region, by industrial origin, and by crop type. The diffusion of agricultural innovations among farmers is described using data on approvals of genetically modified crops, and on cultivated areas actually planted. Studies of the subsequent impacts of agricultural research show that private sector research is making an important contribution to agricultural productivity growth in some countries and could make an even larger impact if government policies were more favorable. The conclusion provides a review of economic and policy determinants affecting private incentives, and some policy prescriptions to encourage further investment.Farmers, Farm Production and Farm Markets
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What is mineral informatics?
Minerals are information-rich materials that offer researchers a glimpse into the evolution of planetary bodies. Thus, it is important to extract, analyze, and interpret this abundance of information to improve our understanding of the planetary bodies in our solar system and the role our planet's geosphere played in the origin and evolution of life. Over the past several decades, data-driven efforts in mineralogy have seen a gradual increase. The development and application of data science and analytics methods to mineralogy, while extremely promising, has also been somewhat ad hoc in nature. To systematize and synthesize the direction of these efforts, we introduce the concept of "Mineral Informatics,"which is the next frontier for researchers working with mineral data. In this paper, we present our vision for Mineral Informatics and the X-Informatics underpinnings that led to its conception, as well as the needs, challenges, opportunities, and future directions of the field. The intention of this paper is not to create a new specific field or a sub-field as a separate silo, but to document the needs of researchers studying minerals in various contexts and fields of study, to demonstrate how the systemization and enhanced access to mineralogical data will increase cross- and interdisciplinary studies, and how data science and informatics methods are a key next step in integrative mineralogical studies. © 2023 Anirudh Prabhu, Shaunna M. Morrison, Peter Fox, Xiaogang Ma, Michael L. Wong, Jason R. Williams, Kenneth N. McGuinness, Sergey V. Krivovichev, Kerstin Lehnert, Jolyon Ralph, Barbara Lafuente, Robert T. Downs, Michael J. Walter, and Robert M. Hazen, published by Mineralogical Society of America.Open access articleThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]