Experimental Analysis OF Heat Transfer and Pressure Drop for Tube-in-fin Heat Exchangers Using Ice Slurry in HVAC System

AbstractIce slurries can be used both for cold storage in place of chilled water or ice and as a secondary refrigerant since, up to certain concentrations, they can be pumped directly through distribution pipe works and heat exchangers. For ice slurries to become more widely accepted, however, more engineering information is required on fluid flow and heat transfer characteristics. This paper reports on the results of experimental investigations of heat transfer and pressure drop of 14 % ice fraction, 16% ethylene glycol, and 70% water by volume flowing in a tube-fin exchanger. And the airflow rate is varied from between 1 m/s to 3 m/s. In this flows range, due the ice fractions caused around a 5% in the pressure drop. The overall heat transfer capacity of the heat exchanger was found to increase by more than 26% with melting ice slurry flow compared to chilled water flow. In a practical application, for a given thermal load this would lead to between 70% and 80% reduction in flow rate and pressure drop compared to chilled water cooling systems.Keywords: Heat transfer, Pressure drop, Ice slurr

Molecular Characterization of Jatropha curcas Resources and Identification of Population-Specific Markers

Jatropha curcas L. is cited as one of the best candidates for future oil and biodiesel production. It is widespread in many tropical and subtropical countries but has not yet received much genetic improvement. The objective of this study was to collect Jatropha germplasm and characterize it with molecular markers. A total of 64 genotypes, collected from seven geographic locations on two continents, were analyzed with 32 simple sequence repeat and two candidate gene-specific primers (ISPJ-1 gene and Curcin-P2 gene promoter). In general, markers were found to be highly conserved, and many (40%) were monomorphic in the studied populations. Polymorphic primers, which amplified population-specific fragments, were identified. The polymorphic information content of the polymorphic markers ranged from 0.03 to 0.47. Genetic similarity analysis identified two distinct groups at 0.73 DICE similarity coefficient. Group I included germplasm collected from the islands of Cuba and Cape Verde, and group II consisted of Brazil, Mozambique, and Senegal populations. Island genotypes were found to be very distinct compared to their mainland counterparts. Sequencing of monomorphic fragments identified single nucleotide polymorphism (SNP) between these two groups. High-resolution melting analysis of the SNP in the Jcps9 locus further confirmed the two gene pools. Sequencing of polymorphic fragments of the Jc03 locus identified a deletion in a (GT)4 repeat motif in the genotypes in group II. Several population-specific microsatellites and SNP markers have been recognized. The distinct Jatropha genotypes and the population-specific molecular markers identified in this study will be valuable resources in breeding programs

Mapping the d1 and d2 dwarfing genes and the purple foliage color locus P in pearl millet

The d1 and d2 dwarfing genes and the P purple foliage color gene were placed on the restriction fragment length polymorphism (RFLP)-based molecular marker linkage map of pearl millet [Pennisetum glaucum (L.) R. Br.] using a mapping population based on a cross of inbred lines IP 18293 (D1/D1, d2/d2, P/P) and Tift 238D1 (d1/d1 D2/D2 p/p). A skeleton genetic linkage map of 562 cM (Haldane function) was constructed using 33 RFLP markers and these three morphological markers. The D1/d1 plant height locus mapped to pearl millet linkage group 1, while the D2/d2 plant height locus and the P/p foliage color locus mapped to pearl millet linkage group 4. Loose genetic linkage was observed between the D2/d2 and P/p loci, with 42% repulsion-phase recombination corresponding to 92 cM (Haldane). This loose linkage of morphological marker loci detected on pearl millet LG4 can likely find use in applied pearl millet breeding programs, as host plant resistances to both downy mildew and rust have previously been identified in this genomic region. Such exploitation of these morphological markers in an applied disease resistance breeding program would require development of appropriate genetic stocks, but the relatively loose genetic linkage between d2 and P suggests that this should not be difficult

Methodological Advancement in Molecular Markers to Delimit the Gene(s) for Crop Improvement

Molecular markers, in recent years, have accelerated plant breeding methods significantly with an objective of crop improvement. At present a variety of molecular markers are available and the choice of using a particular type of marker depends on the user. With the advances in the area of genomics, new type and gene-derived markers as well as novel approaches such as genetical genomics, linkage disequilibrium (LD)- based association mapping, etc. have been developed for identification of “perfect” markers for their use in breeding practices. The present article provides an overview on presently available but main type of molecular markers and their use in trait mapping, map-based cloning, estimation of diversity in germplasm collection to understand the population structure as well as in the area of comparative genomics. While dealing the above topics, major emphasis have been given on modern genomics tools and approaches such as functional molecular markers (EST-SSRs, EST-SNPs, SFPs), expression genetics or genetical genomics, high throughput approaches and automation technologies, public databases, etc. Utilization of modern genomics approaches such as functional genomics coupled with molecular marker technologies have a great potential to facilitate plant breeding practices and thus marker-assisted breeding seems to be evolved to genomics-assisted breeding in the near future

Assembly and analysis of a qingke reference genome demonstrate its close genetic relation to modern cultivated barley

Qingke, the local name of hulless barley in the Tibetan Plateau, is a staple food for Tibetans. The availability of its reference genome sequences could be useful for studies on breeding and molecular evolution. Taking advantage of the third-generation sequencer (PacBio), we de novo assembled a 4.84-Gb genome sequence of qingke, cv. Zangqing320 and anchored a 4.59-Gb sequence to seven chromosomes. Of the 46,787 annotated 'high-confidence' genes, 31 564 were validated by RNA-sequencing data of 39 wild and cultivated barley genotypes with wide genetic diversity, and the results were also confirmed by nonredundant protein database from NCBI. As some gaps in the reference genome of Morex were covered in the reference genome of Zangqing320 by PacBio reads, we believe that the Zangqing320 genome provides the useful supplements for the Morex genome. Using the qingke genome as a reference, we conducted a genome comparison, revealing a close genetic relationship between a hulled barley (cv. Morex) and a hulless barley (cv. Zangqing320), which is strongly supported by the low-diversity regions in the two genomes. Considering the origin of Morex from its breeding pedigree, we then demonstrated a close genomic relationship between modern cultivated barley and qingke. Given this genomic relationship and the large genetic diversity between qingke and modern cultivated barley, we propose that qingke could provide elite genes for barley improvement

Legume Genomics and Breeding

This chapter contains sections titled; Introduction; Constraints in Crop Production; Genomic Resources in Legumes;Trait Mapping and Marker-Assisted Selection; Summary and Prospects; Acknowledgments; Literature Cite