Varying Temperature Range Research Articles

Pyrolysis of heavy metal contaminated Avicennia marina biomass from phytoremediation: Characterisation of biomass and pyrolysis products

Sustainable management of contaminated biomass derived from phytoremediation of metal(loid) polluted soil and water is of great importance to avoid environmental risks from secondary pollution of the contaminants. In this regard, pyrolysis technology may reduce the environmental risk of the contaminants and produce different bio-products from contaminated biomass. In this work, slow pyrolysis of Avicennia marina biomass was conducted to compare the pyrolysis properties of heavy-metal-contaminated and uncontaminated biomass and its potential to generate pyrolytic products, such as biochar, bio-oil and pyrolytic gas at a varying temperature range from 300 to 800 °C. The results indicated that the properties of biomass and derivatives were affected significantly by both pyrolysis temperature and the presence of heavy metal(loid)s. The heavy metal(loid)s in biomass contributed to higher biochar and pyrolytic gas yields at the expense of bio-oil. Increasing pyrolysis temperature induced the volatilisation of heavy metal(loid)s in biochar samples. At the same pyrolysis temperature, the contaminants significantly increased the ash content whilst decreased the fixed carbon content in biochars (p < 0.05). Furthermore, it was noticed that the quality of bio-oils was improved by the presence of metal(loid)s, as the pyrolysis of contaminated biomass produced 8–11% hydrocarbons in the bio-oil samples with less oxygenated compounds as compared to uncontaminated biomass that produced only 4–5.8% hydrocarbons in the bio-oil. Moreover, biomass abound with trace metal(loid)s produced more H2 and CO2 during pyrolysis compared to uncontaminated biomass. Overall, this study demonstrated that pyrolysis is an efficient way for converting heavy metal contaminated biomass obtained from phytoremediation into valuable products, contributing to the sustainability of phytoremediation.

The density, dynamic viscosity and kinematic viscosity of protic and aprotic polar solvent (pure and mixed) systems: An experimental and theoretical insight of thermophysical properties

We report herein the thermophysical properties of pure protic and aprotic polar solvents (water, dimethyl sulfoxide and N,N-dimethyl formamide) and their mixed (binary and ternary) systems. The experimental density (ρ) and viscosity (η) were determined for these systems by varying temperature range from 293.15 K to 343.15 K. The excess properties (viz., excess molar volumes (VE), excess thermal expansion coefficient (αE), viscosity deviation (Δη) and excess Gibb's free energy (ΔGE) for viscous flow) were computed for mixed systems from experimental values. The excess properties of the mixed systems show clearly a non-ideal behaviour. Especially, a mixture of water with aprotic polar component show better thermophysical properties than pure systems. The pure (DMF) system shows increasing dynamic viscosity values at higher temperature region. Both the binary as well as ternary mixed systems show maximum activation energy (Ea) in the presence of water depicts their thermal stability of the mixed systems. The thermal expansion coefficient (α) also revealed increase in the thermal behaviour for the protic-aprotic systems. In addition to that, thermodynamic parameters are also evaluated for better understanding of thermal stability.

Improving gas sensing performance by oxygen vacancies in sub-stoichiometric WO3-x.

Sub-stoichiometric WO3−x has provided an alternative platform to investigate oxygen vacancies in gas sensors based on metal-oxides. We present an experimental study on the influence of sub-stoichiometric WO3−x phase upon gas sensing performance. High-quality WO3−x nanostructures with several x values (WO3, W19O55, W5O14, W18O49) were synthesized and used to fabricate H2S gas sensors. Temperature programmed desorption of oxygen (O2-TPD) shows that oxygen absorption behaviors of the as-prepared WO3−x nanostructures are affected by oxygen vacancies, which played a critical role in the detection of H2S at varying temperature range. We find that oxygen vacancies in sub-stoichiometric WO3−x facilitate the ionosorption process and in turn enhance the performance of the gas sensor.

Biobutanol production using pea pod waste as substrate: Impact of drying on saccharification and fermentation

Increasing worldwide energy consumption and limited availability of fossil fuels propelled the researchers to develop advanced fuels (biobutanol) for its commercial development. In the present work, pea pod waste from vegetable sector was investigated for biobutanol production using C. acetobutylicum B 527 through series of steps viz. compositional analysis, drying study, saccharification, detoxification, and fermentation. Proximate analysis suggested that pea pod waste is rich in holocellulose content with 32.08% of cellulose and 21.12% of hemicellulose on dry basis and hence has a huge potential to be used as carbon source during biobutanol production. In order to enhance storability and subsequent saccharification, drying kinetics of pea pod waste was carried out in varied temperature range (60–120 °C) and the experimental data was simulated by using moisture diffusion control model. Saccharification of pea pod waste samples resulted into total sugar release of 30–48 g/L. Subsequently, 95% phenolics and 30% acetic acid were removed using activated charcoal detoxification. The acetone-butanol-ethanol (ABE) fermentation of detoxified pea pod waste slurries resulted in 4.25–5.94 g/L total solvents with about 50% sugar utilization. Overall, the utilization of pea pod waste will serve as basis for valorization of vegetable waste biomass for ABE production.

Fabrication of mullite from lithomargic clay via spark plasma sintering

Abstract Lithomargic clay has low plasticity and therefore makes it difficult to form ceramic bodies without addition of binder using conventional sintering technique. Plasticity can be improved by addition of clay binders. However, clay binders increase SiO2 content and thus lower the refractoriness of the sintered compacts. In this study, mullite was fabricated from lithomargic clay using spark plasma sintering without addition of clay binder. The mullite compacts were produced at a varying temperature range of 1300–1400 °C for a holding time of 300 s under pressure of 30 MPa. Densification and physico-mechanical properties were studied. Densification and hardness values of mullite increased with temperature while apparent porosity and water absorption decreased with temperature. The hardness of mullite sintered at 1400 °C reached 1112 HV. Mullite produced has the potential to be used for lightweight applications.

Improved selectivity of SnO2:C alloy nanoparticles towards H2 and ethanol reducing gases; role of SnO2:C electronic interaction

In the present study, changes in the sensing properties of SnO2 on Carbon incorporation have been investigated in detail. The gas sensing response of size-selected SnO2 and SnO2:C alloy nanoparticles prepared by gas phase deposition method have been investigated for H2 and ethanol over a varied temperature range (50°C–200°C). The incorporation of carbon into SnO2 lattice results in a large change in the sensing behaviour towards the two gases both having reducing nature. SnO2:C nanoparticles show positive sensing response for H2 and negative sensing response for ethanol, whereas SnO2 nanoparticles show a normal sensing response of an n-type semiconductor towards both the reducing gases. Observed values of activation energy of sensing and energy levels of O-vacancies observed in the PL spectra of SnO2 and SnO2:C are consistent with these results. (i) Catalytic C–H interaction and (ii) modified work function of SnO2 and C on hydrogenation resulting in alteration of electronic exchange between SnO2 and C, and (iii) passivation effect of carbon during SnO2-ethanol interaction along with a possibility of reduction in SnO2 sites in SnO2:C nanoparticles, are responsible for the observed behaviour. The present study shows that the incorporation of C in SnO2 nanoparticles results in excellent selectivity towards H2 and ethanol (both having reducing nature) in the low temperature range, normally not observed in oxide based resistive sensors.

Effect modification in the temperature extremes by mortality subgroups among the tropical cities of the Philippines

BackgroundTemperature–mortality relationships have been extensively probed with varying temperature range but with relatively similar patterns and in some instances are being modified by specific mortality groups such as causes of mortality, sex, and age.ObjectiveThis study aimed to determine the risk attributions in the extreme temperatures and also identified the risks associated with the various mortality subgroups.DesignWe used the 2006–2010 daily average meteorological and daily mortality variables from the Philippine Atmospheric Geophysical and Astronomical Services Administration and Philippine Statistics Authority–National Statistics Office, respectively. Mortality data were divided according to cause (cardiovascular and respiratory), sex, and age (0–14 years, 15–64 years, and >64 years). We performed a two-stage analysis to estimate the extreme temperature effects stratified by the different mortality subgroups to observe the effect modification.ResultsIn the pooled analysis, greater risks were observed in the extreme high temperature (99th temperature percentile; RR (relative risk)=2.48 CI: 1.55–3.98) compared to the extreme low temperature (1st temperature percentile; RR=1.23 CI: 0.88–1.72). Furthermore, effect modification by mortality subgroups was evident, especially higher risks for extreme temperatures with respiratory-related diseases, women, and elderly.ConclusionsBoth sex and age were found to effect modify the risks in extreme temperatures of tropical cities; hence, health-related policies should take these risk variations into consideration to create strategies with respect to the risk population.

Ultrathin metamaterial-based perfect absorbers for VHF and THz bands

An ultrathin and angularly stable metamaterial perfect absorber (MPA) is demonstrated for VHF-band using four connected split-square resonators structure and low-cost fabrication process. The total incoming energy of electromagnetic wave (at 250 MHz) is consumed inside the efficient thickness, which is 240 times smaller than the absorption wavelength of MPA. Our MPA works well for a very wide range of incident angle up to 45° of electromagnetic wave and exhibits the polarization-independent behavior. Furthermore, by scaling the initial design and integrating a ferroelectric material (strontium titanate), a thermo-tunable ultrathin MPA is realized in the THz region. At room temperature (300 K), the thickness of THz MPA reaches roundly 1/300 of the working wavelength. In addition, a fractional frequency shift of 49% at the absorption over 90% can be controlled in the varied temperature range from 150 to 400 K. Our results presents good candidates for potential devices operating from the radio to the THz range.

Lithium Iron Phosphate Intelligent SOC Prediction for Efficient Electric Vehicle

This paper presents modelling techniques for Lithium Iron Phosphate (LiFePO4) battery in an electric vehicle. Artificial intelligence techniques namely multi-layered perceptron neural network (MLPNN) and Elman recurrent neural network are devised to estimate the energy remained in the battery bank which referred to state of charge (SOC). The New European Driving Cycle (NEDC) test data is used to excite the cells in driving cycle-based conditions under varied temperature range [0-55]°C. Accurate SOC prediction is a key function for satisfactory implementation of Battery Supervisory System (BSS). It is demonstrated that artificial intelligence methods can be effectively used with highly accurate results. The accuracy of the modeling results is demonstrated through validation and correlation tests.

Investigation on Performance Characteristics of Petrol Engine Using Alternate Fuel

In the present scenario the S.I. engines being used in automotives by various manufactures are not properly suitable to out climatic condition. As our country is among tropical countries where the variation in the temperature is having very vast range i. e. from 0oC to 48oC in various regions of the country. Looking in to this vast varying temperature range it is very difficult to say that which temperature is most suited to operating condition of engines and gives us best performance level as for as SFC and brake power is concerned. In my work I have tried to investigate the best option to run the S.I. engine and simultaneously to maintain the emission norms. Petrol reserves are getting exhausted and it is recommended to find the alternate solution to it. In the present work the potential of methanol is being explored to serve as alternate fuel. This work is carried out with the use of petrol and methanol on a three cylinder, four stroke, petrol Maruti 800 engine connected to eddy current type dynamometer for loading was adopted to study engine power, fuel economy, engine exhaust emissions of hydrocarbon, oxides of nitrogen in the exhaust. The performance results that are reported include brake power and specific fuel consumption (SFC) as a function of engine coolant temperature; i.e. 50oC, 60oC, 70oC and 80oC with varying engine speed of 1500, 2000, 2500, rpm. Today research and development in the field of gasoline engines have to face a double challenge: on the one hand, fuel consumption has to be reduced, while on the other hand, ever more stringent emission standards have to be fulfilled. The development of engines with its complexity of in-cylinder processes requires modern development tools to exploit the full potential in order to reduce fuel consumption. There are many strategies for improving fuel economy and reducing exhaust emission. Hydrocarbon emission (HC) and carbon monoxide (CO). And finally it is concluded that no remarkable difference is recorded. With use of methanol instead of petrol the variation is marginal and can be attributed to the cycle temp and combustion efficiency. Thus methano l is recommended for use as an alternative fuel for petrol engine in coming future.

Influence of chain structure on crystal polymorphism of poly(lactic acid). Part 1: effect of optical purity of the monomer

The influence of chain structure on crystal polymorphism of poly(lactic acid) (PLA) with high l-lactic acid content (97.8–100 %) is detailed in this contribution. Upon usual processing conditions of PLA, only α and α′ crystals grow, which makes these two polymorphs of major interest for research. The two crystal modifications have similar chain packing, which complicates their quantitative analysis by diffraction methods. The two crystal modifications are instead easily identified by analysis of the crystallization kinetics, which varies not only with temperature, but also with crystal polymorphism. The dependence of the rate of ordering on temperature shows two distinct maxima around 105–110 and 120–125 °C, which are related to growth of α′ and α crystals, respectively. Addition of d-lactic acid co-units leads to a decrease of the overall crystallization rate of PLA, as well as of the rate of spherulite growth (G) of both the crystal modifications. The relative crystallization rates of α and α′ forms are highly affected by stereoregularity, especially in the PLA grades that have a high crystallization rate. A high d-lactic acid content results not only in an overall slower crystal growth, but also in a varied temperature range where each of the two crystal modifications prevail, with a shift to lower temperatures of both the maxima of the G vs. temperature plots, indicating that inclusion of d-lactic acid units in the PLA chain affects crystallization rate of both α and α′ crystal modifications.

Culture and physiological variability in Rhizoctonia solani, responsible for foliar and lesions on aerial part of soybean

Foliar blight of soybean is one of the major fungal diseases. Rhizoctonia solani isolated from soybean growing in tarai regions of Uttarakhand. Six isolates of R. solani has been characterized on the basis of cultural and physiological nature such as colony diameter, growth, colour and sclerotia formation were recorded. Potato Dextrose Agar (PDA) was found best for growth and development. Two isolates (Lakhimpur and Pantnagar) covered the whole plates (90 mm) in 48 hrs. However, maximum number of sclerotia and weight was recorded on Czapek Dox agar medium. Overall radial growth supporting is recorded Corn Meal Agar Medium. Varied range of temperatures i.e. 10, 15, 25, 30, 35 and 400C was tested and found better growth of different isolates of R. solani at 10 - 400C, with an optimum growth temperature at 300C. Isolates were grown on five broth media (Asthana &amp; Hawkers, Potato Dextrose Agar, Czapek’s Dox Agar, Corn Meal Agar and Richards Agar) for fresh, dry weight and oat meal broth culture filtrates of all isolates was used in phytotoxic effects. It recorded that maximum fresh and dry weight was observed on corn meal agar medium. The maximum reduction in radical and plumule length of germinating seeds were recorded in Haldichaur isolate.

Effect of Seasonal Variations, Altitude and Geographical Location on the Onset of Dawn Chorus in Three Bird Species in Middle East

One of the behavioral aspects of passerine birds is their dawn chorus. Therefore the onset of dawn chorus in three bird species (blackbirds, bulbuls and house sparrows) was investigated in different seasons, years and geographical locations with varying temperature range and altitude. Results show that the onset of dawn chorus varied for the different seasons of the year but was similar from year to year and was not affected by varying geographical locations with different altitude and climate. Results also show that different bird species start singing independently of each other. This is the first time that such parameters are investigated for any bird species.

“A Comparative Thermal Kinetic Investigation of the Fresh and Stale-Expired Protein Denaturing Transition”

Protein, in eggs, has a biological quality greater than any other natural food. The quality of the protein in eggs means that all egg protein can be used for synthesis and limits the amount burned as fuel or stored as fat. Hence, the quality of egg protein can be an important factor in weight loss and essential to understand more facts about egg proteins. In this study, a comparative thermal kinetic investigation of the fresh and stale-expired proteins was made using calorimetric technique. Three different scans as temperature scans, heating rate scans and time scans were performed using differential scanning calorimetry varying temperature range from 0 °C to 200 °C and heating ramp rates from 1 °C/min to 20 °C/min. Two protein samples were used; one obtained from a fresh egg and other from the stale-expired egg from the same batch. The denaturing transition for the stale egg protein occurred at the higher temperature with smaller enthalpy and needed a larger activation than the fresh protein. This indicates that stale-expired egg provides less energy and need more energy to be activated or burnt than the fresh egg protein. Hence, the stale protein would increase more fat and need more energy to burn if eaten in the food. Keywords: Calorimetry, fresh and stale Protein, Kinetics, Activation Energy, Denaturing transition, thermodynamics

High temperature mechanical properties of rapidly quenched Zr50Ni27Nb18Co5 amorphous alloy

The high temperature mechanical properties of Zr50Ni27Nb18Co5 amorphous ribbons, proposed as metallic membrane material for hydrogen purification are presented. The mechanical behavior of the amorphous alloy, which generally does not exhibit a super-cooled liquid region, can be categorized into varying temperature regimes. A strain rate dependent phenomenon was observed between 425°C < T < 490°C in the strain rate range of 10−6s−1 to 10−2s−1. However, the alloy did not exhibit Newtonian-flow characteristics at the varied test temperature and strain rate range employed in this study. Detailed analyses indicated that in these temperature regimes structural changes occur, resulting in the formation of nanocrystalline phases. The results from these mechanical tests corroborated with the microstructural changes that occurred at these temperatures/strain rates.

The effects of performance and cleaning cycles of new tubular ceramic microfiltration membrane fouled with a model yeast suspension

The efficiency of crossflow microfiltration processes is limited by membrane fouling and concentration polarization leading to permeate flux decline during operation. The experiments that were carried out in the laboratory were conducted to determine and investigate the performance, behaviour and the fouling susceptibility of new ceramic tubular microfiltration membranes during the crossflow filtration of yeast suspensions. The tubular membranes of nominal pore size 0.5 microns were fouled over a varied range of concentration, temperatures, pH, crossflow velocities and system pressures. The typical filtration conditions were at a temperature of 25°C, a system pressure of 1.5 bar and a concentration of 0.03 g/L yeast suspension. These parameters varied during subsequent investigations. After each experiment, the membrane and the rig were cleaned using a three stage cleaning process and was reused in order to replicate industrial filtration conditions. The effects of repeated fouling and cleaning cycles upon membrane flux over time and cleaning efficiency are investigated and their influence over time is also documented. For every experiment, the flux data was recorded over a 50 min period and the membrane was changed after the PWF declined considerably due to excessive fouling over time. Chemical cleaning consisted of a sequential application of a 1% caustic solution through the rig followed by a 2% hypochlorite solution and a 2% nitric solution, all at 50°C. The permeate flux was shown to decrease with filtration time during the development of the fouling layer. Once the fouling layer was developed and established, there appeared to be a leveling of permeate flux. The experimental results are presented in the report and the flux values at different conditions are presented.

The decagonal quasicrystal Al65Co15Cu20 studied by the Mössbauer effect

A systematic57Fe Mössbauer effect study in a varying temperature range between 5.0 and 296.6 K and in anexternal magnetic field of 9.0 T on a high-quality stable decagonal quasicrystalAl65Co15Cu19.9Fe0.1 is presented. It is shown that the iron atoms are located in two distinctclasses of sites. The values of the principal component of the electric fieldgradient tensor and the asymmetry parameter at these sites are, respectively,−1.90(10) × 1021 V m−2, 0.97(15)and −3.95(12) × 1021 V m−2, 0.00(17). The average quadrupole splitting decreases with temperature asT3/2. The vibrations of the Fe atoms are well described by a Debye model, with the Debyetemperature of 546(7) K.

Leakage conduction behavior in electron-beam-cured nanoporous silicate films

This letter explores the application of electron-beam curing on nanoporous silicate films. The electrical conduction mechanism for the nanoporous silicate film cured by electron-beam radiation has been studied with metal-insulator-semiconductor capacitors. Electrical analyses over a varying temperature range from room temperature to 150°C provide evidence for space-charge-limited conduction in the electron-beam-cured thin film, while Schottky-emission-type leaky behavior is seen in the counterpart typically cured by a thermal furnace. A physical model consistent with electrical analyses is also proposed to deduce the origin of conduction behavior in the nanoporous silicate thin film.

5544696 Enhanced nucleate boiling heat transfer for electronic cooling and thermal energy transfer

A Rankine cycle modification is presented where a mixture is used as a working medium instead of a pure substance. Evaporation and condensation occur over a varied temperature range and partial condensation heat recovery is possible, thereby increasing the efficiency of the cycle.

The use of an absorber-generator heat exchanger in power production

A Rankine cycle modification is presented where a mixture is used as a working medium instead of a pure substance. Evaporation and condensation occur over a varied temperature range and partial condensation heat recovery is possible, thereby increasing the efficiency of the cycle.