Superconducting properties of Y(Ba1-xCax)2Cu3O7-δ (0 ≤ x ≤ 0.05) system

A series of polycrystalline compounds with a nominal composition of Y(Ba1‐xCax)2Cu3O7−δ (0⩽x⩽0.05) had been synthesized using solid state reaction method. Crystal structure of those samples was characterized by Rietveld refinement on the x‐ray powder diffraction data. It was found that the structural parameters were not changed appreciably with Ca content in Y(Ba1‐xCax)2Cu3O7−δ. While c‐axis remained almost unchanged, both a and b axes decreased slightly leading to the decrease in orthorhombicity of Y‐123 phase. The superconducting transition temperature, Tc was determined by measuring the change of electrical resistance versus temperature (50 K–300 K) using a four point probe technique. The Tc was observed to decrease gradually by Ca doping from 91 K for x = 0.00 to 88 K for x = 0.05 attributable to oxygen vacancy disorder. In addition, the superconducting transition breadth, ΔT, increased with Ca doping because of degraded crystallinity or inhomogeneity of the samples. Finally, scanning electron micrographs indicated grain growth induced by Ca doping

The superconductivity of YBa2Cu3O7-δ reacted with nano-SiC

We report on the influence of nano-SiC as an additive on the superconductivity of polycrystalline YBa2Cu3O7-δ (YBCO) prepared via solid state reaction method. In particular, we studied the characteristic of superconducting transition temperature (Tc), crystal structure and microstructure of the YBCO system. X-ray diffraction patterns show the dominance of YBCO (123) phase in all the samples. The a and c axes increase slightly while the b-axis decreases with SiC addition causing the reduced orthorhombicity. Measurements of resistance versus temperature show that the normal state changes from metallic to semiconducting like behavior upon increasing the amount of additive from 1.5 wt.% onwards. The Tc-onset was found to decrease from 91 K for pure samples to 78 K for the 2 wt. % sample attributable to the adverse effect of Si. The broadening in superconducting transition breadth, ΔT indicates degraded crystallinity or inhomogeneity in the samples caused by SiC additions

A Complete Denture By Rapid Prototyping With Reverse Engineering Approach

This paper presents a denture fabrication process by implementing the techniques used in the addictive manufacturing which is 3D printing technology involving reverse engineering method. A three dimensional scanner was used to obtain the surface data of the complete partial denture model that received from the dental clinic. The scanned data was refined using the Geomagic Studio and then converted to STL format for CAD and 3D printing application. The complete dentures design was converted to STL format for production of the product using the Projet HD 1000 machine which is one of the rapid prototyping (RP) technique. Cold cure acrylic resin (VERTEX, Castavaria) was used as the denture material on the gum section. On the teeth section, the composite resin will be applied to add an aesthetic value to the part. Then, the final dentures were polished and tested on an edentulous model to test the bite and adaptability. The finished denture has been test to ensure the adaptability and comfortability. Thus, the user felt comfort while tested the printed denture. The method of fabrication by addictive manufacturing is much faster compared to traditional method. The time taken to complete the denture is 5 hours. Otherwise by conventional method consumed about 15 hours. The result for the denture has been checked to ensure satisfactory and good accuracy. Unlike the traditional method of fabrication, this research has potential to reduce fabrication period of time and make it easier to replace a new set of denture that had been broken

Emerging patterns of genetic diversity in the critically endangered Malayan tiger (Panthera tigris jacksoni)

Southeast Asia experiences some of the highest deforestation in the world. Loss of tropical forest typically leads to widespread habitat fragmentation, with detrimental effects on dispersal ability and gene flow—particularly for large carnivores. We conducted mtDNA and microsatellite analysis to assess—for the first time—contemporary patterns of genetic diversity in the Malayan tiger. We collected 295 suspected carnivore samples in Peninsular Malaysia, from which we identified 26 as originating from tiger using 16 polymorphic microsatellite loci, comprising 22 individual tigers. Despite limitations of the study, our findings suggest tiger subpopulations in the north of the peninsula maintain some genetic connectivity and migration between two putative geographic subpopulations in the Main Range and Greater Taman Negara, with negligible population segregation due to dispersal barriers such as road infrastructure. We identified consistently lower levels of genetic diversity in tigers in the Greater Taman Negara region compared to tigers in the Main Range and small but emerging differences in nuclear and mitochondrial genetic diversity. Our mtDNA haplotype and nuclear DNA analyses suggest the levels of genetic diversity in Malayan tigers may be amongst some of the lowest of the surviving tiger subspecies, though the study is limited both in scale and genomic loci. Our findings are consistent with an expected lag between the rapid decline of tigers in Peninsular Malaysia by over 95% in the last 70 years and observed differences in their levels of genetic diversity

Data from: Resource availability and roosting ecology shape reproductive phenology of rain forest insectivorous bats

Bats in temperate and subtropical regions typically synchronize birth of a single young with peaks in resource availability driven by local climate patterns. In tropical rain forest, insects are available throughout the year, potentially allowing departures from seasonal monoestry. However, reproductive energy budgets may be constrained by the cost of commuting to foraging grounds from distant roosts. To test these hypotheses, we simultaneously tracked female reproductive activity of 11 insectivorous bat species, insect biomass, and local weather variables for 20 months in a Malaysian rain forest. Five species roost in forest structures and hence have low commuting costs, whereas six species depend on caves, which are limited in the landscape, and are presumed to incur higher commuting costs to foraging sites. Monthly insect biomass was positively correlated with monthly rainfall, and there was a significant relationship between insect biomass and lactation in cave-roosting but not forest-roosting species. Cave-roosting species were seasonally monoestrus, with parturition confined to a two-month period, whereas in forest-roosting species, pregnancy and lactation were recorded throughout the year. Our results suggest that the energetic costs of commuting from roosts to foraging grounds shape annual reproductive patterns in tropical rain forest insectivorous bats. Ongoing changes in forest landscapes are likely to increase these costs for cave-roosting bats, further restricting reproductive opportunities. Climate change is projected to influence the timing of rainfall events in many tropical habitats, which may disrupt relationships between rainfall, insect biomass, and bat reproductive timing, further compromising reproductive success

Nurul-Ain et al_Reproductive phenology of tropical insectivorous bats

Raw data of bats capture and insect biomass

Resource partitioning among bat species in Peninsular Malaysia rice fields

Resource partitioning among tropical bats in agricultural areas of Peninsular Malaysia remains unclear. This study was conducted to evaluate resource partitioning among bats by examining their fecal samples. The main bat species sampled included: Rhinolophus coelophyllus, Rhinolophus malayanus, Rhinolophus pusillus, Rhinolophus refulgens, Taphozous melanopogon and Hipposideros larvatus. Two harp traps were set at different elevations on a hilltop (Gunung Keriang) and two high nets were used in neighboring rice fields at three sites, for three consecutive nights per sampling from April 2021 to February 2022. A total of 301 bats and 1,505 pellets were analyzed using a conventional approach which examined the fecal sample under the microscope. All of the bat species within the study had insects from the order Coleoptera, Lepidoptera, Diptera and Hemiptera in their diet. Larger bats exhibited a greater variety of prey consumption. Male individuals were observed to be generalists while female individuals were specialists, particularly during pregnancy and lactating reproductive stages. Bat species and insect order had a significant impact on the percentage fragment frequency of the insects consumed. Rhinolophus coelophyllus specialized in feeding on Coleoptera and Diptera, H. larvatus fed on Coleoptera, R. malayanus fed on Hemiptera, R. pusillus and T. melanopogon fed on Lepidoptera. Future molecular analysis can be carried out to further identify the insect pests consumed by these bats up to species level. These findings enhance our understanding of bats’ ecological roles in agricultural landscapes and contribute to conservation and pest management strategies

BAT SPECIES IN THE FORESTS RESERVES OF PENANG ISLAND AFTER 2010: WITH TWO MORE NEW RECORDS FILED

Bat communities in Old World tropical rainforests serve various ecological roles to sustain their habitats, yet may be vulnerable to the loss of their natural habitats. Moreover, the exact biological and ecological roles of the majority of the bats in Penang Island are still understudied. Therefore, we conducted surveys at four selected primary forest reserves (Bukit Genting, Penang National Park, Relau and Teluk Bahang) on Penang Island to determine the forest bat species currently living on the island. This study was conducted using harp traps and mist nets from February 2015 to August 2016. A total of 135 individuals, four families and 11 species of bats were caught with an average capture rate of 2.7 bats per harp-trap night and 4.05×10-3 bats per mist-net metre square hour. Cynopterus brachyotis was the only Pteropodids species recorded and Rhinolophus affinis has the highest capture number in our surveys. Along with Coelops frithii reported earlier, two new species, namely Myotis muricola and Phoniscus jagorii, were documented for the first time in Penang Island, indicating that the forest bat community here is still undersurveyed. Our survey results suggested that the primary forests on Penang Island are valuable for bat conservation in terms of hosting uncommon forest species

Ultrasound use by Sunda colugos offers new insights into the communication of these cryptic mammals

<p>Recent reports of the use of ultrasound for communication by nocturnal mammals have expanded our understanding of behaviour in these animals. The vocal repertoire of colugos has so far only been known to include audible sound. Here, we report the use of ultrasound calls by Sunda colugos (<i>Galeopterus variegatus,</i> order Dermoptera). We recorded one type of call emitted by seven individuals with mean individual frequencies between 37.4 ± 0.6 and 39.2 ± 0.7 kHz during its maximum energy and lasting 28.7 ± 1.6 to 46.9 ± 21.1 ms. Each call showed 3–36 sequential pulses with individual mean interpulse intervals between 423.0 ± 101.4 and 1230.0 ± 315.4 ms. High frequency calls may serve as cryptic anti-predator alarm calls. Our observations suggest that more species of nocturnal mammals may use ultrasound to communicate, and that further studies are needed to determine the occurrence, function and diversity of these calls.</p

Mechanical Characteristics Of Oil Palm Fiber Reinforced Thermoplastics As Filament For Fused Deposition Modeling (FDM)

Fibers are increasingly in demand for a wide range of polymer composite materials. This study’s purpose was the development of oil palm fiber (OPF) mixed with the thermoplastic material acrylonitrile butadiene styrene (ABS) as a composite filament for fused deposition modeling (FDM). The mechanical properties of this composite filament were then analyzed. OPF is a fiber extracted from empty fruit bunches, which has proved to be an excellent raw material for biocomposites. The cellulose content of OPF is 43%–65%, and the lignin content is 13%–25%. The composite filament consists of OPF (5%, mass fraction) in the ABS matrix. The fabrication procedure included alkalinizing, drying, and crushing the OPF to develop the composite. The OPF/ABS materials were prepared and completely blended to acquire a mix of 250 g of the material for the composition. Next, the FLD25 filament extrusion machine was used to form the OPF/ABS composite into a wire. This composite filament then was used in an FDM-based 3D printer to print the specimens. Finally, the printed specimens were tested for mechanical properties such as tensile and flexural strength. The results show that the presence of OPF had increased the tensile strength and modulus elasticity by approximately 1.9% and 1.05%, respectively. However, the flexural strength of the OPF/ABS composite had decreased by 90.6% compared with the virgin ABS. Lastly, the most significant outcome of the OPF/ABS composite was its suitability for printing using the FDM method