Range Of Environmental Temperatures Research Articles

Seasonal Variation in Population Dynamics of Helminth Parasites in Clarias batrachus from Natural wetlands of Sylhet, Bangladesh

A year round field investigations were conducted with the aim to examine the seasonal variation in population dynamics of helminth parasites in Clarias batrachus from different natural aquatic habitat of north-eastern region of Bangladesh, Sylhet. This article summarizes the percentage of prevalence, mean intensity, abundance and index of infestation of helminth parasites in the C. batrachus during different months and seasons of the year in accordance with temperature, humidity and rainfall. The investigation period were categorized into four seasons i.e. pre-monsoon (February-April), monsoon (May-July), post-monsoon (August- October) and winter (November- January). A total 180 C. batrachus host individuals were examined and among them 139 (67.87%) specimens were found to be infested with 2205 individuals of parasites of three different groups namely trematode, cestode and nematode. Almost (100%) prevalence of helminth infestation were recorded from both male and female C. batrachus during the winter (Nov-Jan), followed by (Feb-April) pre-monsoon (66.67-86.67%) and (Aug-Sep) post-monsoon (66.67-80.00%) while lowest (53.33-60.00%) in monsoon or rainy season (May-July). Lower range of environmental temperature (21.05–25.050C), associated with moderate humidity (62.00-64.00%) and scarcity of rainfall increases the intensity of helminthes parasitic infestation in C. batrachus. In consistent to this, with the gradual increasing in ambient temperature (28.01- 30.010C) and humidity (75.00-89.00%) associated with moderate rainfall (33.40-790.90 mm) declining the intensity of helminthes infestation in C. batrachus of the study area.International Journal of Natural Sciences (2015), 5(2) 86-89

Design of carbon/epoxy–aluminum hybrid upper arm of the pantograph of high-speed trains using adhesive bonding technique

The upper arm of a steel pantograph was replaced by a high stiffness carbon/epoxy composite–aluminum hybrid structure to enhance the mechanical performance of a pantograph for high-speed trains. By considering driving conditions such as high voltage discharge and a wide range of environmental temperatures, the composite laminates were applied to the inner surface of an aluminum pipe by using adhesive bonding with an epoxy adhesive. The bending stiffness of the slender arm structure was the most important mechanical performance criterion; therefore, only simple stacking sequences ([0]10T, [±5]5T, [±10]5T), which guarantee the higher bending stiffness, were tried to determine the mechanical performance such as maximum deflection and natural frequency. Thermal stress due to environmental temperature (−35°C to 65°C) was also evaluated by finite element analysis. The generated stresses in the bonding layers were closely investigated, and it was found that the maximum stress was below 60% of the material strength of the epoxy adhesive under various temperature conditions.

Modeling and analysis of hydraulic dashpot for impact free operation in a shut-off rod drive mechanism

Rotary hydraulic dashpot used for shut-off rod drive mechanism application of a nuclear reactor has been studied in this paper for impact free operation. The rotary hydraulic dashpot has been modeled as a system with 1 degree of freedom (DOF) and the simulation results are experimentally validated. The dashpot is modeled as a hinge joint with moving and fixed vanes as rigid bodies. Shut-off rods are used to shut-down a nuclear reactor and hydraulic dashpot absorbs the energy of freely falling shut-off rod at the end of rod travel. With the increase in the environmental temperature the dashpot becomes underdamped at a point because of reduction in the viscosity of oil and results into impact on mechanism components. Hydraulic dashpot designs are finalized with an optimum combination of dashpot clearances and oil viscosity to meet the drop time criterion and impact free operation at room temperature as well as at elevated temperature. Also with the change in mechanical loads the dashpot becomes underdamped. So the study is further extended to see the effects of various parameters such as moment of inertia, constraint angle and applied moment on the dashpot. Study is focused on obtaining dashpot responses in terms of relative rotation, relative angular velocity and relative angular acceleration at various environmental temperatures. Finite element commercial code COMSOL Multiphysics 5.1 has been used for numerical simulations. Equations for both rigid body dynamics and heat transfer in solids are solved simultaneously. Thus, energy absorbed and local temperature rise in the dashpot operation is also obtained. Both simulation and experimental results at wide range of environmental temperature are presented and compared in this paper. This study forms a good tool to design a hydraulic dashpot, which gives impact free operation in a shut-off rod free fall.

Low-Temperature Cross-Sensitivity Refractive Index Sensor Based on Single-Mode Fiber With Periodically Modulated Taper

In this paper, a single-mode fiber with periodically modulated tapers has been fabricated using electric arc discharge with a fiber splicer. Such a fiber with periodic tapers could effectively adjust the light propagation. The refractive index (RI) sensitivity of the proposed microfiber under different ambient RI environments has been analyzed. Experimental results show that it has an RI sensitivity of $\sim 490.9$ nm/RIU for a linear RI range from 1.3642 to 1.4015. The temperature response has also been experimentally investigated, which showing that this device possesses a low-temperature cross sensitivity, and the temperature-induced wavelength shift perturbation is <0.5 nm for an environmental temperature range of 22.5°C–80°C. Combining such desirable merits as simple fabrication procedure, compactness, low cost, and low-temperature sensitivity of the periodically modulated microfiber, this sensor is expected to find potential applications in fields, such as multi-parameter measurement and biochemical applications.

A seven-sensor configuration method for testing thermal error of a horizontal machining center with linear optical grating scale

A precision testing method based on a seven-sensor configuration is presented in this paper to quantify thermal errors (drifting, elongation, tilting) of the mandrel cross-section, for an example horizontal machining center with linear optical grating scale. Three tri-axial displacement sensors with 120° spread angles and 36 thermal couples are mounted on judiciously chosen locations to record the temperatures and thermal expansions for various operating conditions. Based on the measurements covering a wide range of spindle locations, environment temperatures, coolant temperature, and spindle rotational speeds, we found that (i) the maximum thermal drifts of the mandrel are 11.3 µm in the x direction with a compensation rate of 62%, and 165.3 µm in the y direction with a compensation rate of 93%, (ii) the maximum thermal tilt of the mandrel is 0.005°, and (iii) the thermal elongation of the mandrel in the z direction, which could not be compensated by the linear optical grating scale, is 51.9 µm. From a correlation study, the thermal elongation of the mandrel is most closely correlated to the temperatures recorded for the thermal couple mounted at the front surface of the spindle bearing with a correlation coefficient of 0.83.

밀폐된 공간 내 공랭식 PEMFC의 자연대류 열전달에 대한 실험적 연구

This study presents an experiment investigation on natural convection heat transfer of air-cooling Proton exchange membrane fuel cells (PEMFCs) in a enclosure system for unmanned aerial vehicles (UAVs). Considered are replacing fuel cell stack with Aluminum block for heat generating inside a enclosure chamber. The volume ratio of fuel cell stack and chamber for simulation to the actual size of aerial vehicle is 1 to 15. The parameters considered for experimental study are the environmental temperature range from <TEX>$25^{\circ}C$</TEX> to <TEX>$-60^{\circ}C$</TEX> and the block heat input of 10 W, 20 W and 30 W. Effect of the thermal conductivity of the block and power level on heat transfer in the chamber are investigated. Experimental results illustrate the temperature rise at various locations inside the chamber as dependent upon heat input of fuel cell stack and environmental temperature. From the results, dimensionless correlation in natural convection was proposed with Nusselt number and Rayleigh number for designing air-cooling PEMFC powered high altitude long endurance (HALE) UAV.

High‐Speed Spun PET Nanocomposites for Smart Multifunctional Approaches

ABSTRACTHigh‐speed spinning at 3000 m/min with a remarkable potential for mass production was conducted to produce continuous fine‐multifilament nanocomposite yarns on a pilot plant scale. Nanocomposite fabrics were produced via a simultaneous draw‐texturing process followed by weft knitting. The fabric samples were examined in terms of thermophysiological comfort, tribological performance, and the resistance against structural degradation under ultraviolet (UV) irradiation. The abrasion resistance was improved by enhancement of rupture work while decreasing the crystallinity. Improvement of more than 200% was recorded in fabric abrasion resistance upon using a sample containing the maximum content of nanoparticles (NPs). A remarkable improvement in resistance was recorded against structural degradation under UV irradiation for the UV‐irradiated polyethylene terephetalate (PET) nanocomposites as compared to UV‐irradiated monocomponent PET. The study of the effect of UV irradiation confirmed our recent finding about a UV‐induced solid‐state interaction mechanism in the case of PET nanocomposites as well as polypropylene (PP) nanocomposites. Optimal comfortable characteristic was achieved upon using 5 wt% nanosilver masterbatch. At low environment temperatures, this sample has lower vapor permeability than monocomponent PET fabrics. By raising the temperature, the rate of improving the vapor permeability for the composite fabrics became markedly more than that of monocomponent fabrics. It is of great interest that these desirable changes in permeability can be achieved in the range of common environment temperatures (i.e. 15–35°C), which exactly meet the body requirements. Consequently, nanocomposite fabrics can smartly adapt the permeability requirements for the human body by changing the environment temperatures.

Stress Response at the Cellular and Biochemical Levels Indicates the Limitation of the Environmental Temperature Range for Eastern Siberian Populations of the Common GastropodLymnaea stagnalis

ABSTRACT Temperature is a major environmental factor that influences all aquatic organisms. Our objective was to expose individuals of Lymnaea stagnalis from an Eastern Siberian population to wide temperature gradients to determine whether they express a thermal stress response and what mechanisms are involved in this process. Several parameters of the cellular mechanisms of thermal resistance were tested under the experimental conditions: the level of lipid peroxidation, the synthesis of heat shock protein HSP70, the activities of antioxidative enzymes and changes in the content of energy-associated metabolites. The results of this study show that the temperature at which the cellular and biochemical stress-response is activated in the L. stagnalis from Eastern Siberian lakes directly corresponds to environmental temperature within the range of 3 to 15°C. The exposure of the gastropods to temperatures outside this range resulted in the activation of HSP70 synthesis, changes in the activities of antioxida...

Method for EMC antenna factor temperature error correction

In order to reduce the influence of the outfield environmental temperature and improve the measuring precision of electromagnetic compatibility( EMC) test equipment,a method for antenna factor temperature error correction was presented. Firstly,according to the principle of two antenna calibration with 1 m distance,the antenna receiving characteristic influenced by temperature control device made by radome material under the condition of near field was theoretically deduced. Combined with the simulation analysis and test results proved that the test error can be controlled in the permitted range by using the temperature control device. Secondly,on this basis the antenna factor variation with temperature and temperature error correction surface for typical antenna was obtainedby the actual test. In the end,the method was verified by comparing the test result uder standard conditions with the test result under the open area test site( OATS) condition.The results prove that this method can expand the environmental temperature range of use from- 40℃ to 50℃by antenna factor temperature error correction on the premise of not reducing measurement precision,and suitable for the antenna factor temperature error correction in EMC double cone antenna and log periodic antenna and the double ridged horn antenna,etc.

Rabies vaccine preserved by vaporization is thermostable and immunogenic

A rabies vaccine that is thermostable over a range of ambient environmental temperatures would be highly advantageous, especially for tropical regions with challenging cold-chain storage where canine rabies remains enzootic resulting in preventable human mortality. Live attenuated rabies virus (RABV) strain ERAG333 (R333E) was preserved by vaporization (PBV) in a dry, stable foam. RABV stabilized using this process remains viable for at least 23 months at 22°C, 15 months at 37°C, and 3h at 80°C. An antigen capture assay revealed RABV PBV inactivated by irradiation contained similar levels of antigen as a commercial vaccine. Viability and antigen capture testing confirmed that the PBV process stabilized RABV with no significant loss in titer or antigen content. Live attenuated and inactivated RABV PBV both effectively induced RABV neutralizing antibodies and protected mice from peripheral RABV challenge. These results demonstrate that PBV is an efficient method for RABV stabilization.

Comparison of whole mitochondrial genome sequences from two clades of the invasive ascidian, Didemnum vexillum

The mitochondria are the main source of cellular energy production and have an important role in development, fertility, and thermal limitations. Adaptive mitochondrial DNA mutations have the potential to be of great importance in determining aspects of the life history of an organism. Phylogenetic analyses of the globally invasive marine ascidian Didemnum vexillum using the mitochondrial cytochrome c oxidase 1 (COX1) coding region, revealed two distinct clades. Representatives of one clade (denoted by ‘B’) are geographically restricted to D. vexillum's native region (north-west Pacific Ocean, including Japan), whereas members of the other clade (denoted by ‘A’) have been introduced and become invasive in temperate coastal areas around the world. Persistence of clade B's restricted distribution may reflect it being inherently less invasive than clade A. To investigate this we sought to determine if the two clades differ significantly in other mitochondrial genes of functional significance, specifically, alterations in amino acids encoded in mitochondrial enzyme subunits. Differences in functional mitochondrial genes could indicate an increased ability for clade A colonies to tolerate a wider range of environmental temperature. Full mitochondrial genomic sequences from D. vexillum clades A and B were obtained and they predict significant sequence differences in genes encoding for enzymes involved in oxidative phosphorylation. Diversity levels were relatively high and showed divergence across almost all genes, with p-distance values between the two clades indicating recent divergence. Both clades showed an excess of rare variants, which is consistent with balancing selection or a recent population expansion. Results presented here will inform future research focusing on examining the functional properties of the corresponding mitochondrial respiration enzymes, of A and B clade enzymes. By comparing closely related taxa that have differing distributions it is possible to identify genes and phenotypes suited to particular environments. The examination of mitochondrial genotypes, and associated enzyme functioning, across populations may aid in our understanding of thermal tolerance and environmental adaptation.

Transcriptome Profiles of Populus euphratica upon Heat Shock stress.

Heat stress, which strongly affects plant performance and often results in reduced vegetative growth and yields depression, has become an increasingly serious global problem. Populus euphratica Oliv. which has been considered as a tree model for the study of plant response to abiotic stresses, could be resistant to an extremely wide environmental temperature range (–40 °C to 45 °C). Previous study is mainly focused on its gene regulation upon drought and salt stress. However, little is known about gene regulation at the global transcriptome level upon heat stress. To understand the gene network controlling heat stress in P. euphratica, a transcriptome sequencing using Illumina Hiseq 2000 was performed to generate a 10 gigabases depth for each sample in the tissue of leaf. 119,573 unigeneswere generated with an average length of 474 bp. Approximately 49,605 (41.49%) unigenes exhibited significantly different expressions between two libraries. Among these unigenes, 11,165 (9.34%) were upregulated and 38,440 (32.15%) were down regulated. Heat shock proteins classified as molecular chaperones showed a significant percentage (1.13%) in the up regulated group. Heat responsive genes, such as polyubiquitins, were over expressed in heat treated sample. GO enrichment analysis revealed that the Go terms for differentially expressed unigenes were significantly enriched in hormone-mediated signal, biological process regulation and metabolic process regulation. Our data revealed a global transcriptome picture of P. euphratica in response to heat shock. The identified potential heat stress-related transcripts can be used to infer the gene regulation networks underlying the molecular mechanisms of heat response in P. euphratica.

Water—air gas exchange of elemental mercury: An experimentally determined mercury diffusion coefficient for Hg0 water—air flux calculations

The evasion of elemental mercury (Hg0) from water surfaces is a key process in biogeochemical mercury cycling. Knowledge of the Hg0 diffusion coefficient (DHG0) in water is essential for Hg0 water—air flux calculations, but no measured value has been available. In this study, DHG0 was measured in pure water and in water of oceanic salinity within an environmental temperature range between 5°C and 30°C. A diffusion cell was constructed consisting of two chambers separated by an aqueous gel membrane allowing molecular diffusion only. The corresponding parameterizations were developed on the basis of the Eyring equation, which defines an activation energy (Ea) for the diffusion process. The temperature dependences of DHG0 (in cm2 s−1) for freshwater, DfreshHG0 = 0.0335e−(18.63 kJ mol−1)/RT, and for seawater, DseaHG0 = 0.0011e−(11.06 kJ mol−1)/RT, with R the gas constant and T the temperature in Kelvin, were thus obtained with an error of ±15%. Whereas the measured DfreshHG0 was in good agreement with the theoretical proposals of a molecular dynamics (MD) simulation, DseaHG0 was clearly lower, probably because of the unaccounted effect of the polarization of mercury atoms in the salt solution, which hampers diffusion. In geochemistry applications, use of the newly determined DseaHG0 instead of the DHG0 from MD simulations would have differential effects on determinations of mercury emissions from the world's oceans. The effect on the tropical ocean would be the largest, decreasing the Hg0 water—air flux estimate by 20%. Toward higher latitudes (∼50°), the calculated emission would drop by about 10%. On the basis of a recent large data set, the estimated amount of mercury released by the Atlantic Ocean would decrease by approximately 17%.

Cool temperatures reduce antifungal activity of symbiotic bacteria of threatened amphibians--implications for disease management and patterns of decline.

Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is a widespread disease of amphibians responsible for population declines and extinctions. Some bacteria from amphibians’ skins produce antimicrobial substances active against Bd. Supplementing populations of these cutaneous antifungal bacteria might help manage chytridiomycosis in wild amphibians. However, the activity of protective bacteria may depend upon environmental conditions. Biocontrol of Bd in nature thus requires knowledge of how environmental conditions affect their anti-Bd activity. For example, Bd-driven amphibian declines have often occurred at temperatures below Bd’s optimum range. It is possible these declines occurred due to reduced anti-Bd activity of bacterial symbionts at cool temperatures. Better understanding of the effects of temperature on chytridiomycosis development could also improve risk evaluation for amphibian populations yet to encounter Bd. We characterized, at a range of temperatures approximating natural seasonal variation, the anti-Bd activity of bacterial symbionts from the skins of three species of rainforest tree frogs (Litoria nannotis, Litoria rheocola, and Litoria serrata). All three species declined during chytridiomycosis outbreaks in the late 1980s and early 1990s and have subsequently recovered to differing extents. We collected anti-Bd bacterial symbionts from frogs and cultured the bacteria at constant temperatures from 8°C to 33°C. Using a spectrophotometric assay, we monitored Bd growth in cell-free supernatants (CFSs) from each temperature treatment. CFSs from 11 of 24 bacteria showed reduced anti-Bd activity in vitro when they were produced at cool temperatures similar to those encountered by the host species during population declines. Reduced anti-Bd activity of metabolites produced at low temperatures may, therefore, partially explain the association between Bd-driven declines and cool temperatures. We show that to avoid inconsistent antifungal activity, bacteria evaluated for use in chytridiomycosis biocontrol should be tested over a range of environmental temperatures spanning those likely to be encountered in the field.

Upper thermal tolerance of closely related Danio species

The main finding of this study was that measuring maximum heart rate during incremental warming was an effective tool to estimate upper thermal limits in three small cyprinid Danio species, which differed significantly. Arrhenius breakpoint temperature for maximum heart rate, purportedly an index of optimum temperature, was 21·2 ± 0·4, 20·1 ± 0·4 and 18·9 ± 0·8° C (mean ± s.e.) for zebrafish Danio rerio, pearl danio Danio albolineatus and glowlight danio Danio choprae, respectively. The temperature where cardiac arrhythmias were first induced during warming (T(arr)) was 36·6 ± 0·7, 36·9 ± 0·8 and 33·2 ± 0·8° C (mean ± s.e.) and critical thermal maximum (T(Cm)) was 39·9 ± 0·1, 38·9 ± 0·1 and 37·2 ± 0·1° C (mean ± s.e.) for D. rerio, D. albolineatus and D. choprae, respectively. The finding that T(arr) was consistently 3-4° C lower than T(Cm) suggests that collapse of the cardiac life support system may be a critical trigger for upper temperature tolerance. The upper thermal limits established here, which correlate well with a broad natural environmental temperature range for D. rerio and a narrow one for D. choprae, suggest that upper thermal tolerance may be a genetic trait even among closely related species acclimated to common temperatures.

Characterization of the transcriptome and temperature-induced differential gene expression in QPX, the thraustochytrid parasite of hard clams.

BackgroundThe hard clam or northern quahog, Mercenaria mercenaria, is one of the most valuable seafood products in the United States representing the first marine resource in some Northeastern states. Severe episodes of hard clam mortality have been consistently associated with infections caused by a thraustochytrid parasite called Quahog Parasite Unknown (QPX). QPX is considered as a cold/temperate water organism since the disease occurs only in the coastal waters of the northwestern Atlantic Ocean from Maritime Canada to Virginia. High disease development at cold temperatures was also confirmed in laboratory studies and is thought to be caused predominantly by immunosuppression of the clam host even though the effect of temperature on QPX virulence has not been fully investigated. In this study, the QPX transcriptome was sequenced using Roche 454 technology to better characterize this microbe and initiate research on the molecular basis of QPX virulence towards hard clams.ResultsClose to 18,000 transcriptomic sequences were generated and functionally annotated. Results revealed a wide array of QPX putative virulence factors including a variety of peptidases, antioxidant enzymes, and proteins involved in extracellular mucus production and other secretory proteins potentially involved in interactions with the clam host. Furthermore, a 15 K oligonucleotide array was constructed and used to investigate the effect of temperature on QPX fitness and virulence factors. Results identified a set of QPX molecular chaperones that could explain its adaptation to cold temperatures. Finally, several virulence-related factors were up-regulated at low temperature providing molecular targets for further investigations of increased QPX pathogenicity in cold water conditions.ConclusionsThis is one of the first studies to characterize the transcriptome of a parasitic labyrinthulid, offering new insights into the molecular bases of the pathogenicity of members of this group. Results from the oligoarray study demonstrated the ability of QPX to cope with a wide range of environmental temperatures, including those considered to be suboptimal for clam immunity (low temperature) providing a mechanistic scenario for disease distribution in the field and for high disease prevalence and intensity at low temperature. These results will serve as basis for studies aimed at a better characterization of specific putative virulence factors.

Intelligent neonatal monitoring based on a virtual thermal sensor

BackgroundTemperature measurement is a vital part of daily neonatal care. Accurate measurements are important for detecting deviations from normal values for both optimal incubator and radiant warmer functioning. The purpose of monitoring the temperature is to maintain the infant in a thermoneutral environmental zone. This physiological zone is defined as the narrow range of environmental temperatures in which the infant maintains a normal body temperature without increasing his or her metabolic rate and thus oxygen consumption. Although the temperature measurement gold standard is the skin electrode, infrared thermography (IRT) should be considered as an effortless and reliable tool for measuring and mapping human skin temperature distribution and assist in assessing thermoregulatory reflexes.MethodsBody surface temperature was recorded under several clinical conditions using an infrared thermography imaging technique. Temperature distributions were recorded as real-time video, which was analyzed to evaluate mean skin temperatures. Emissivity variations were considered for optimal neonatal IRT correction for which the compensation vector was overlaid on the tracking algorithm to improve the temperature reading. Finally, a tracking algorithm was designed for active follow-up of the defined region of interest over a neonate’s geometry.ResultsThe outcomes obtained from the thermal virtual sensor demonstrate its ability to accurately track different geometric profiles and shapes over the external anatomy of a neonate. Only a small percentage of the motion detection attempts failed to fit tracking scenarios due to the lack of a properly matching matrix for the ROI profile over neonate’s body surface.ConclusionsThis paper presents the design and implementation of a virtual temperature sensing application that can assist neonatologists in interpreting a neonate’s skin temperature patterns. Regarding the surface temperature, the influence of different environmental conditions inside the incubator has been confirming.

An Effective Integration Solution for 100 Gb/s DP-QPSK Coherent Receiver With a Small Skew

We propose and develop a simple hybrid integration solution for a 100 Gb/s dual polarization quadrature phase shift keying coherent receiver. The cost-effective, precise, and passive alignment technique can be used to couple four output waveguides of planar lightwave circuits (PLCs) based 90 ° optical hybrid (OH) with a 1 × 4 photodiode (PD) array directly, adopting an infrared charge-coupled device camera to monitor the light spots, a beam of infrared light to illuminate the light spots and the active areas of PD array, and an epoxy glue to adhere the PLC-based 90 ° OH to the heat sink. Based on this proposed coupling scheme, the responsivity variation for the coherent receiver is less than ±0.18 dB for all PD channels in an environment temperature range of -5°C-80 °C and the skew of this coherent receiver is only 1.96 ps.

内部空孔にCNTを生成したC/C複合材料の開発とそのトライボロジ特性

The purpose of this study is to stabilize the coefficient of friction of carbon-carbon (C/C) composites through wide environmental temperature range by synthesizing the carbon nanotubes (CNTs) on its surface and inner pore. In this study, conventional CFRP was carbonized at 2,200˚C with inert atmosphere to fabricate the C/C composites in which char matrix was made from phenolic resin. CNTs were synthesized on the surface and inner pore of fabricated C/C composites by the thermal chemical vapor deposition method. The coefficient of mutual friction and wear amount between two flat specimens were measured at a constant rotational speed under constant applied pressure by using the disc-type test apparatus. The effect of CNT synthesization on the mutual friction coefficient and its dependence on test temperature were discussed. Frictional coefficient was high and also stable when the CNTs were synthesized on surface and inner pore while the test temperature was changed. The wear amount of modified C/C composites was almost same as that of unmodified one. Test results also showed that the variation of friction coefficient of modified C/C composites during frication test was explained by the variation of local volume fraction of matrix of C/C composites.

Characterization and potential application in mercury bioremediation of highly mercury-resistant marine bacterium Bacillus thuringiensis PW-05

Bacillus thuringiensis PW-05 was isolated from the Odisha coast and was found to resist 50 ppm of Hg as HgCl2 as well as higher concentrations of CdCl2, ZnSO4, PbNO3 and Na2HAsO4. Resistance towards several antibiotics, viz amoxycillin, ampicillin, methicillin, azithromycin and cephradine (CV) was also observed. The mer operon possessed by most of the mercury-resistant bacteria was also found in this isolate. Atomic absorption spectroscopy revealed that the isolate can volatilize >90 % of inorganic mercury. It showed biofilm formation in the presence of 50 ppm HgCl2 and can produce exopolysaccharide under same conditions. The isolate was found to volatilize mercury efficiently under a wide range of environmental parameters, i.e. pH (7 to 8), temperature (25 °C to 40 °C) and salinity (5 to 25 ppt). merA gene expression has been confirmed by real-time reverse transcriptase PCR study. Fourier transform infrared study revealed that -SH and -COOH groups play a major role in the process of adaptation to Hg. Hence, this isolate B. thuringiensis PW-05 shows an interesting potential for bioremediation of mercury.