1,562 research outputs found

    Novel battery thermal management via scalable dew-point evaporative cooling

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    Thermal management is critical to safety, stability, and durability of battery energy storage systems. Existing passive and active air cooling are not competent when the cooling performance, energy efficiency and cost of the thermal management system are drawing concurrent concerns. Here we propose dew-point evaporative cooling as a novel active air-cooling approach for large battery systems. Its capability of cooling the air towards its dew-point temperature with simple working principle and great electrical efficiency offers an ideal solution. Therefore, a scalable dew-point evaporative cooling technology was developed, and a large-scale cooler was constructed which could deliver 2.9–6.7 kW cooling capacity with 8.9–28.9 coefficient of performance (COP). To demonstrate its performance for battery thermal management, we took a 20 Ah lithium iron phosphate (LFP) prismatic pouch cells for a case study whose complex dynamic electrochemical and thermal responses were investigated via lock-in thermography experiments and electrochemical-thermal modeling. The potential of dew-point evaporative cooling for battery cooling was explored via the multi-physics coupling of battery and cooler models. This study elucidates that dew-point evaporative cooling can efficiently cool a battery by 3.0–13.6 °C lower than the cases with only forced convection, and control the battery operating temperature within an ideal operating range of 20–40 °C

    The inhibition of plant and animal adenosine 3':5'-cyclic monophosphate phosphodiesterases by a cell-division-promoting substance from tissues of higher plant species.

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    One member of a new class of cell-division-promoting factors, that has been given the trivial name of cytokinesin I, is a potent inhibitor of adenosine 3':5'-cyclic monophosphate phosphodiesterases of both plant and animal origin. Since an adenylate cyclase has been demonstrated in this study to be present in plant cells, the results suggest that cytokinesin I may be exerting its biological effects in promoting division in cells of higher plant species as a regulator of adenosine 3':5'-cyclic monophosphate.published_or_final_versio

    Towards a career in bioinformatics

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    The 2009 annual conference of the Asia Pacific Bioinformatics Network (APBioNet), Asia's oldest bioinformatics organisation from 1998, was organized as the 8th International Conference on Bioinformatics (InCoB), Sept. 9-11, 2009 at Biopolis, Singapore. InCoB has actively engaged researchers from the area of life sciences, systems biology and clinicians, to facilitate greater synergy between these groups. To encourage bioinformatics students and new researchers, tutorials and student symposium, the Singapore Symposium on Computational Biology (SYMBIO) were organized, along with the Workshop on Education in Bioinformatics and Computational Biology (WEBCB) and the Clinical Bioinformatics (CBAS) Symposium. However, to many students and young researchers, pursuing a career in a multi-disciplinary area such as bioinformatics poses a Himalayan challenge. A collection to tips is presented here to provide signposts on the road to a career in bioinformatics. An overview of the application of bioinformatics to traditional and emerging areas, published in this supplement, is also presented to provide possible future avenues of bioinformatics investigation. A case study on the application of e-learning tools in undergraduate bioinformatics curriculum provides information on how to go impart targeted education, to sustain bioinformatics in the Asia-Pacific region. The next InCoB is scheduled to be held in Tokyo, Japan, Sept. 26-28, 2010

    Predicting protein functions by relaxation labelling protein interaction network

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    <p>Abstract</p> <p>Background</p> <p>One of key issues in the post-genomic era is to assign functions to uncharacterized proteins. Since proteins seldom act alone; rather, they must interact with other biomolecular units to execute their functions. Thus, the functions of unknown proteins may be discovered through studying their interactions with proteins having known functions. Although many approaches have been developed for this purpose, one of main limitations in most of these methods is that the dependence among functional terms has not been taken into account.</p> <p>Results</p> <p>We developed a new network-based protein function prediction method which combines the likelihood scores of local classifiers with a relaxation labelling technique. The framework can incorporate the inter-relationship among functional labels into the function prediction procedure and allow us to efficiently discover relevant non-local dependence. We evaluated the performance of the new method with one other representative network-based function prediction method using E. coli protein functional association networks.</p> <p>Conclusion</p> <p>Our results showed that the new method has better prediction performance than the previous method. The better predictive power of our method gives new insights about the importance of the dependence between functional terms in protein functional prediction.</p

    Higher body mass index may induce asthma among adolescents with pre-asthmatic symptoms: a prospective cohort study

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    <p>Abstract</p> <p>Background</p> <p>Limited studies have prospectively examined the role of body mass index (BMI) as a major risk factor for asthma during adolescence. This study investigates whether BMI is associated with increased risk of developing physician-diagnosed asthma during 12-month follow-up among adolescents with undiagnosed asthma-like symptoms at baseline.</p> <p>Methods</p> <p>A total of 4,052 adolescents with undiagnosed asthma-like symptoms at baseline were re-examined after a 12-month follow-up. Asthma cases were considered confirmed only after diagnosis by a physician based on the New England core and International Study of Asthma and Allergies in Childhood (ISAAC) criteria video questionnaires, and accompanying pulmonary function tests. Logistic regression analyses were used to evaluate the relationship of BMI and the risk of acquiring asthma.</p> <p>Results</p> <p>The results indicated that girls with higher BMI were at an increased risk of developing asthma during the 12-month follow-up. The odds ratios for girls developing physician-diagnosed asthma were 1.75 (95% CI = 1.18-2.61) and 1.12 (95% CI = 0.76-1.67), respectively, for overweight and obesity as compared to the normal weight reference group after adjustment for other covariates. A similar relationship was not observed for overweight and obese boys who were also significantly more active than their female counterparts.</p> <p>Conclusions</p> <p>Increased BMI exaggerates the risk of acquiring asthma in symptomatic adolescent females but not in adolescent males. Thus, gender is an important modifier of BMI-related asthma risk. Additional research will be required to determine whether the increased asthma risk results from genetic, physiological or behavioural differences.</p

    Distant sequences determine 5′ end formation of cox3 transcripts in Arabidopsis thaliana ecotype C24

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    The genomic environments and the transcripts of the mitochondrial cox3 gene are investigated in three Arabidopsis thaliana ecotypes. While the proximate 5′ sequences up to nucleotide position −584, the coding regions and the 3′ flanking regions are identical in Columbia (Col), C24 and Landsberg erecta (Ler), genomic variation is detected in regions further upstream. In the mitochondrial DNA of Col, a 1790 bp fragment flanked by a nonanucleotide direct repeat is present beyond position −584 with respect to the ATG. While in Ler only part of this insertion is conserved, this sequence is completely absent in C24, except for a single copy of the nonanucleotide direct repeat. Northern hybridization reveals identical major transcripts in the three ecotypes, but identifies an additional abundant 60 nt larger mRNA species in C24. The extremities of the most abundant mRNA species are identical in the three ecotypes. In C24, an extra major 5′ end is abundant. This terminus and the other major 5′ ends are located in identical sequence regions. Inspection of Atcox3 transcripts in C24/Col hybrids revealed a female inheritance of the mRNA species with the extra 5′ terminus. Thus, a mitochondrially encoded factor determines the generation of an extra 5′ mRNA end

    On minimizing coding operations in network coding based multicast: an evolutionary algorithm

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    In telecommunications networks, to enable a valid data transmission based on network coding, any intermediate node within a given network is allowed, if necessary, to perform coding operations. The more coding operations needed, the more coding resources consumed and thus the more computational overhead and transmission delay incurred. This paper investigates an efficient evolutionary algorithm to minimize the amount of coding operations required in network coding based multicast. Based on genetic algorithms, we adapt two extensions in the proposed evolutionary algorithm, namely a new crossover operator and a neighbourhood search operator, to effectively solve the highly complex problem being concerned. The new crossover is based on logic OR operations to each pair of selected parent individuals, and the resulting offspring are more likely to become feasible. The aim of this operator is to intensify the search in regions with plenty of feasible individuals. The neighbourhood search consists of two moves which are based on greedy link removal and path reconstruction, respectively. Due to the specific problem feature, it is possible that each feasible individual corresponds to a number of, rather than a single, valid network coding based routing subgraphs. The neighbourhood search is applied to each feasible individual to find a better routing subgraph that consumes less coding resource. This operator not only improves solution quality but also accelerates the convergence. Experiments have been carried out on a number of fixed and randomly generated benchmark networks. The results demonstrate that with the two extensions, our evolutionary algorithm is effective and outperforms a number of state-of-the-art algorithms in terms of the ability of finding optimal solutions

    On the Complexity of Scheduling in Wireless Networks

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    We consider the problem of throughput-optimal scheduling in wireless networks subject to interference constraints. We model the interference using a family of K-hop interference models, under which no two links within a K-hop distance can successfully transmit at the same time. For a given K, we can obtain a throughput-optimal scheduling policy by solving the well-known maximum weighted matching problem. We show that for K > 1, the resulting problems are NP-Hard that cannot be approximated within a factor that grows polynomially with the number of nodes. Interestingly, for geometric unit-disk graphs that can be used to describe a wide range of wireless networks, the problems admit polynomial time approximation schemes within a factor arbitrarily close to 1. In these network settings, we also show that a simple greedy algorithm can provide a 49-approximation, and the maximal matching scheduling policy, which can be easily implemented in a distributed fashion, achieves a guaranteed fraction of the capacity region for "all K." The geometric constraints are crucial to obtain these throughput guarantees. These results are encouraging as they suggest that one can develop low-complexity distributed algorithms to achieve near-optimal throughput for a wide range of wireless networksopen1

    Advanced model for the calculation of meshing forces in spur gear planetary transmissions

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    This paper presents a planar spur gear planetary transmission model, describing in great detail aspects such as the geometric definition of geometric overlaps and the contact forces calculation, thus facilitating the reproducibility of results by fellow researchers. The planetary model is based on a mesh model already used by the authors in the study of external gear ordinary transmissions. The model has been improved and extended to allow for the internal meshing simulation, taking into consideration three possible contact scenarios: involute–involute contact, and two types of involute-tip rounding arc contact. The 6 degrees of freedom system solved for a single couple of gears has been expanded to 6 + 3n degrees of freedom for a planetary transmission with n planets. Furthermore, the coupling of deformations through the gear bodies’ flexibility has been also implemented and assessed. A step-by-step integration of the planetary is presented, using two typical configurations, demonstrating the model capability for transmission simulation of a planetary with distinct pressure angles on each mesh. The model is also put to the test with the simulation of the transmission error of a real transmission system, including the effect of different levels of external torque. The model is assessed by means of quasi-static analyses, and the meshing stiffness values are compared with those provided by the literature.The authors would like to acknowledge Project DPI2013-44860 funded by the Spanish Ministry of Science and Technology
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