Thermal performance of loop heat pipes with smooth and rough porous copper fiber sintered sheets

Smooth and rough porous copper fiber sintered sheets, employed here as wicks for loop heat pipes for the first time, were fabricated using a low-temperature solid-phase sintering method. The capillary performance of these porous copper fiber sintered sheets were analyzed and discussed. The influence of the surface morphology, filling ratio, and working fluid on the thermal resistance, evaporator wall temperature, and start-up time of the loop heat pipes were investigated. The results showed that the capillary pumping amount of working fluid for both smooth and rough porous copper fiber sintered sheets initially increases rapidly, and then gradually attains a stable state. The curve of the capillary pumping amount of working fluid can be described as a function that increases exponentially over time. When rough porous copper fiber sintered sheets are used as wicks and deionized water is used as the working fluid, the capillary pumping amount is maximized. Compared to smooth porous copper fiber sintered sheets, loop heat pipes with rough porous copper fiber sintered sheets exhibit a shorter start-up time, lower thermal resistance, and lower evaporator wall temperature. For a filling ratio in the range of 15–45%, loop heat pipes with rough porous copper fiber sintered sheets and a 30% filling ratio show lower thermal resistance and a lower evaporator wall temperature. Ultimately, the use of deionized water as the working fluid with a 30% filling ratio enables loop heat pipes with rough porous copper fiber sintered sheets to be stably operated at a heat load of 200 W

Genetic Diversity Of Duabanga Moluccana Using Dominant Dna Markers Based On Inter-Simple Sequence Repeats In Sarawak

Duabanga moluccana or locally known as Sawih is a widely known forest tree species for its multipurpose timber and other natural products such as fibers. Genetic diversity investigation of this species can provide baseline information for indirect selection in tree improvement programme. This study has employed Inter Simple Sequence Repeat (ISSR) technique to assess the genetic diversity and relatedness within and between three populations of D. moluccana located in Sarawak, namely, Mukah, Tatau (Bintulu) and Niah. A total of 151 loci from 90 individuals were successfully amplified with 6 selected ISSR primers and the percentage of polymorphic loci was 90.1%. The Shannon’s diversity index showed that D. moluccana in Mukah natural forest (0.429) was the most diverse compared to Tatau (Bintulu) (0.362) and Niah natural forest (0.387). Neighbour joining tree were constructed to show relationship among the selected populations. The overall populations were completely clustered into three main groups, according to their corresponding population. Based on these results, it implies that D. moluccana trees are genetically diverse among populations

Neutrino Masses, Mixing and New Physics Effects

We introduce a parametrization of the effects of radiative corrections from new physics on the charged lepton and neutrino mass matrices, studying how several relevant quantities describing the pattern of neutrino masses and mixing are affected by these corrections. We find that the ratio omega = sin theta / tan theta_atm is remarkably stable, even when relatively large corrections are added to the original mass matrices. It is also found that if the lightest neutrino has a mass around 0.3 eV, the pattern of masses and mixings is considerably more stable under perturbations than for a lighter or heavier spectrum. We explore the consequences of perturbations on some flavor relations given in the literature. In addition, for a quasi-degenerate neutrino spectrum it is shown that: (i) starting from a bi-maximal mixing scenario, the corrections to the mass matrices keep tan theta_atm very close to unity while they can lower tan theta_sol to its measured value; (ii) beginning from a scenario with a vanishing Dirac phase, corrections can induce a Dirac phase large enough to yield CP violation observable in neutrino oscillations.Comment: 14 pages, 21 figures. Uses RevTeX4. Added several comments and references. Final version to appear in PR

Applications Of Genomics To Plantation Forestry With Kelampayan In Sarawak

Wood-based industries in Sarawak are increasingly encouraged to adapt to “new wood” from planted forests composed of fast-growing species such as Kelampayan with short rotation cycle (6-8 years). The rationale is that natural forests at the most produce about 3m3 /ha/yr of commercial timber, whereas plantations can produce annually from 10m3 /ha to 30m3 /ha of commercial timber. It is estimated at least 30 million seedlings are required for annual planting or reforestation programmes to meet the increasing global demand for raw materials. To date, several molecular genetics studies have been completed for Kelampayan. These include genetic diversity of Kelampayan, genetic marker (SSRs) development, ‘Touch-incubate-PCR’ approach for preparing plant tissues for high throughput genotyping, and transcriptomics and bioinformatics on wood formation of Kelampayan. This information provides a useful resource for genomic selection of Kelampayan aiming at the production of high value forests for maximum returns

Impact of inter- and intra-individual variation, sample storage and sampling fraction on human stool microbial community profiles

Stools are commonly used as proxies for studying human gut microbial communities as sample collection is straightforward, cheap and non-invasive. In large-scale human population surveys, however, sample integrity becomes an issue as it is not logistically feasible for researchers to personally collect stools from every participant. Instead, participants are usually given guidelines on sample packaging and storage, and asked to deliver their stools to a centralised facility. Here, we tested a number of delivery conditions (temperature, duration and addition of preservative medium) and assessed their effects on stool microbial community composition using 16S rRNA gene amplicon sequencing. The largest source of variability in stool community composition was attributable to inter-individual differences regardless of delivery condition. Although the relative effect of delivery condition on community composition was small compared to inter-individual variability (1.6% vs. 60.5%, permutational multivariate analysis of variance [PERMANOVA]) and temporal variation within subjects over 10 weeks (5.2%), shifts in microbial taxa associated with delivery conditions were non-systematic and subject-specific. These findings indicated that it is not possible to model or accurately predict shifts in stool community composition associated with sampling logistics. Based on our findings, we recommend delivery of fresh, preservative-free stool samples to laboratories within 2 hr either at ambient or chilled temperatures to minimise perturbations to microbial community composition. In addition, subsamples from different fractions of the same stool displayed a small (3.3% vs. 72.6% inter-individual variation, PERMANOVA) but significant effect on community composition. Collection of larger sample volumes for homogenisation is recommended

Genomics studies on plantation tree species in Sarawak

Rapid socio-economic changes in the world are having profound impacts on all sectors, including forestry. The increase in global demand for wood requires increase in forest productivity. The alternative is to farm trees in plantations composed of fast-growing species with short rotation cycles (6–8 y). The rationale is that natural forests at the most produce about 3 m3 ha y-1 of commercial timber, whereas plantations can produce annually from 10 m3 ha y-1 of hardwoods to 30 m3 ha-1 of softwoods and thus, decrease the effects of human pressure on our ecosystems while increasing the competitiveness of Sarawak’s forest industry. This is in line with the state government’s aspiration to establish one million hectares of planted forests by year 2020 to meet the increasing demand from both domestic and international markets for raw materials. It is estimated at least 30 million seedlings are required for annual planting or reforestation programmes. In this regard, forest genomics research will help respond to the need to develop adequate tools that enable us to produce quality planting materials that are of faster growth, high yield and high wood quality, and also adapted to local conditions, so that we may achieve economic benefits of great significance. Realizing the need, we have centred our research on the development of tools via biotechnological innovations for tree breeders. Over the years, we have successfully developed: 1) simple sequence repeat (SSR) 173 DNA markers specific for identifying the genetic make-up of two fastgrowing indigenous tree species, i.e. kelampayan and sawih; 2) the ‘Touch-incubate-PCR’ approach for preparing plant tissues for high throughput genotyping, and 3) a kelampayan tree transcriptome database (NcdbEST aka CADAMOMICS) for wood formation. These tools will greatly facilitate the selection of quality planting materials for planted forest development in Sarawak as well as long-term tree improvement activities by integrating genomics into our breeding programme via association mapping. The overall benefit of genomics application to tree improvement programme will be in terms of greater certainty in the outcome of results, specifically the performance of the forest plantations, as well as the savings in time and cost in the production and supply of quality planting materials

Update of the Search for the Neutrinoless Decay τ→μγ\tau\to \mu\gamma

We present an update of the search for the lepton family number violating decay $\tau \to \mu\gamma$ using a complete CLEO II data sample of 12.6 million $\tau^+\tau^-$ pairs. No evidence of a signal has been found and the corresponding upper limit is \BR(\tau \to \mu\gamma) < 1.0 \times 10^{-6} at 90% CL, significantly smaller than previous limits. All quoted results are preliminary.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters

Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe