Displaying publications 481 - 500 of 2919 in total

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  1. Torrefaction of empty fruit bunches under biomass combustion gas atmosphere
    Uemura Y, Sellappah V, Trinh TH, Hassan S, Tanoue KI
    Bioresour Technol, 2017 Nov;243:107-117.
    PMID: 28810504 DOI: 10.1016/j.biortech.2017.06.057
    Torrefaction of oil palm empty fruit bunches (EFB) under combustion gas atmosphere was conducted in a batch reactor at 473, 523 and 573K in order to investigate the effect of real combustion gas on torrefaction behavior. The solid mass yield of torrefaction in combustion gas was smaller than that of torrefaction in nitrogen. This may be attributed to the decomposition enhancement effect by oxygen and carbon dioxide in combustion gas. Under combustion gas atmosphere, the solid yield for torrefaction of EFB became smaller as the temperature increased. The representative products of combustion gas torrefaction were carbon dioxide and carbon monoxide (gas phase) and water, phenol and acetic acid (liquid phase). By comparing torrefaction in combustion gas with torrefaction in nitrogen gas, it was found that combustion gas can be utilized as torrefaction gas to save energy and inert gas.
    Matched MeSH terms: Temperature
  2. Fulltext DC-based smart PV-powered home energy management system based on voltage matching and RF module
    Sabry AH, Hasan WZW, Ab Kadir M, Radzi MAM, Shafie S
    PLoS One, 2017;12(9):e0185012.
    PMID: 28934271 DOI: 10.1371/journal.pone.0185012
    The main tool for measuring system efficiency in homes and offices is the energy monitoring of the household appliances' consumption. With the help of GUI through a PC or smart phone, there are various applications that can be developed for energy saving. This work describes the design and prototype implementation of a wireless PV-powered home energy management system under a DC-distribution environment, which allows remote monitoring of appliances' energy consumptions and power rate quality. The system can be managed by a central computer, which obtains the energy data based on XBee RF modules that access the sensor measurements of system components. The proposed integrated prototype framework is characterized by low power consumption due to the lack of components and consists of three layers: XBee-based circuit for processing and communication architecture, solar charge controller, and solar-battery-load matching layers. Six precise analogue channels for data monitoring are considered to cover the energy measurements. Voltage, current and temperature analogue signals were accessed directly from the remote XBee node to be sent in real time with a sampling frequency of 11-123 Hz to capture the possible surge power. The performance shows that the developed prototype proves the DC voltage matching concept and is able to provide accurate and precise results.
    Matched MeSH terms: Temperature
  3. Fulltext The Effects of Annealing Temperatures on Composition and Strain in Si x Ge1-x Obtained by Melting Growth of Electrodeposited Ge on Si (100)
    Abidin MSZ, Morshed T, Chikita H, Kinoshita Y, Muta S, Anisuzzaman M, et al.
    Materials (Basel), 2014 Feb 24;7(2):1409-1421.
    PMID: 28788521 DOI: 10.3390/ma7021409
    The effects of annealing temperatures on composition and strain in Si
    x
    Ge1-x, obtained by rapid melting growth of electrodeposited Ge on Si (100) substrate were investigated. Here, a rapid melting process was performed at temperatures of 1000, 1050 and 1100 °C for 1 s. All annealed samples show single crystalline structure in (100) orientation. A significant appearance of Si-Ge vibration mode peak at ~400 cm-1 confirms the existence of Si-Ge intermixing due to out-diffusion of Si into Ge region. On a rapid melting process, Ge melts and reaches the thermal equilibrium in short time. Si at Ge/Si interface begins to dissolve once in contact with the molten Ge to produce Si-Ge intermixing. The Si fraction in Si-Ge intermixing was calculated by taking into account the intensity ratio of Ge-Ge and Si-Ge vibration mode peaks and was found to increase with the annealing temperatures. It is found that the strain turns from tensile to compressive as the annealing temperature increases. The Si fraction dependent thermal expansion coefficient of Si
    x
    Ge1-x is a possible cause to generate such strain behavior. The understanding of compositional and strain characteristics is important in Ge/Si heterostructure as these properties seem to give significant effects in device performance.
    Matched MeSH terms: Temperature
  4. Fulltext Mechanical and Microstructural Evaluations of Lightweight Aggregate Geopolymer Concrete before and after Exposed to Elevated Temperatures
    Abdulkareem OA, Abdullah MMAB, Hussin K, Ismail KN, Binhussain M
    Materials (Basel), 2013 Oct 09;6(10):4450-4461.
    PMID: 28788339 DOI: 10.3390/ma6104450
    This paper presents the mechanical and microstructural characteristics of a lightweight aggregate geopolymer concrete (LWAGC) synthesized by the alkali-activation of a fly ash source (FA) before and after being exposed to elevated temperatures, ranging from 100 to 800 °C. The results show that the LWAGC unexposed to the elevated temperatures possesses a good strength-to-weight ratio compared with other LWAGCs available in the published literature. The unexposed LWAGC also shows an excellent strength development versus aging times, up to 365 days. For the exposed LWAGC to the elevated temperatures of 100 to 800 °C, the results illustrate that the concretes gain compressive strength after being exposed to elevated temperatures of 100, 200 and 300 °C. Afterward, the strength of the LWAGC started to deteriorate and decrease after being exposed to elevated temperatures of 400 °C, and up to 800 °C. Based on the mechanical strength results of the exposed LWAGCs to elevated temperatures of 100 °C to 800 °C, the relationship between the exposure temperature and the obtained residual compressive strength is statistically analyzed and achieved. In addition, the microstructure investigation of the unexposed LWAGC shows a good bonding between aggregate and mortar at the interface transition zone (ITZ). However, this bonding is subjected to deterioration as the LWAGC is exposed to elevated temperatures of 400, 600 and 800 °C by increasing the microcrack content and swelling of the unreacted silicates.
    Matched MeSH terms: Temperature
  5. Fulltext A scaling law for distinct electrocaloric cooling performance in low-dimensional organic, relaxor and anti-ferroelectrics
    Shi Y, Huang L, Soh AK, Weng GJ, Liu S, Redfern SAT
    Sci Rep, 2017 09 11;7(1):11111.
    PMID: 28894256 DOI: 10.1038/s41598-017-11633-y
    Electrocaloric (EC) materials show promise in eco-friendly solid-state refrigeration and integrable on-chip thermal management. While direct measurement of EC thin-films still remains challenging, a generic theoretical framework for quantifying the cooling properties of rich EC materials including normal-, relaxor-, organic- and anti-ferroelectrics is imperative for exploiting new flexible and room-temperature cooling alternatives. Here, we present a versatile theory that combines Master equation with Maxwell relations and analytically relates the macroscopic cooling responses in EC materials with the intrinsic diffuseness of phase transitions and correlation characteristics. Under increased electric fields, both EC entropy and adiabatic temperature changes increase quadratically initially, followed by further linear growth and eventual gradual saturation. The upper bound of entropy change (∆Smax) is limited by distinct correlation volumes (V cr ) and transition diffuseness. The linearity between V cr and the transition diffuseness is emphasized, while ∆Smax = 300 kJ/(K.m3) is obtained for Pb0.8Ba0.2ZrO3. The ∆Smax in antiferroelectric Pb0.95Zr0.05TiO3, Pb0.8Ba0.2ZrO3 and polymeric ferroelectrics scales proportionally with V cr-2.2, owing to the one-dimensional structural constraint on lattice-scale depolarization dynamics; whereas ∆Smax in relaxor and normal ferroelectrics scales as ∆Smax ~ V cr-0.37, which tallies with a dipolar interaction exponent of 2/3 in EC materials and the well-proven fractional dimensionality of 2.5 for ferroelectric domain walls.
    Matched MeSH terms: Temperature
  6. Fulltext D-Shaped Polarization Maintaining Fiber Sensor for Strain and Temperature Monitoring
    Qazi HH, Mohammad AB, Ahmad H, Zulkifli MZ
    Sensors (Basel), 2016 Sep 15;16(9).
    PMID: 27649195 DOI: 10.3390/s16091505
    A D-shaped polarization-maintaining fiber (PMF) as fiber optic sensor for the simultaneous monitoring of strain and the surrounding temperature is presented. A mechanical end and edge polishing system with aluminum oxide polishing film is utilized to perform sequential polishing on one side (lengthwise) of the PMF in order to fabricate a D-shaped cross-section. Experimental results show that the proposed sensor has high sensitivity of 46 pm/µε and 130 pm/°C for strain and temperature, respectively, which is significantly higher than other recently reported work (mainly from 2013) related to fiber optic sensors. The easy fabrication method, high sensitivity, and good linearity make this sensing device applicable in various applications such as health monitoring and spatial analysis of engineering structures.
    Matched MeSH terms: Temperature
  7. Fulltext Evaluation of inverter reliability performance due to negative bias temperature instability (NBTI) effects in advance CMOS technology nodes
    Zainudin, M.F., Hussin, H., Halim, A.K.
    Pertanika Journal of Science & Technology, 2017;25(101):295-304.
    MyJurnal
    Negative bias temperature instability (NBTI) is the most concern issue CMOS devices with the scaling
    down of the CMOS technologies. NBTI effect contributes to P-MOSFET device degradation which later
    reduce the performance and reliability of CMOS circuits. This paper presents a reliability simulation study
    based on R-D model on CMOS inverter circuit. HSPICE MOSRA model together with the Predictive
    Technology Model (PTM) was used as to incorporate the NBTI model in the circuit reliability simulation
    study for different technology nodes. PTM of High Performance (HP) models of 16nm, 22nm, 32nm
    and 45nm were used in this simulation study. The atomic hydrogen based model was integrated in the
    simulation. The results show that in a CMOS inverter circuit, the threshold voltage shift of p-MOSFET
    under NBTI stressing increased as the year progressed.. The threshold voltage shift was observed to
    increase up to 45.1% after 10 years of operation. The time exponent, n ~ 0.232 of the threshold voltage
    shift observed indicates that the defect mechanism contributed to the degradation is atomic hydrogen.
    The propagation delay increased to 19.5% over a 10-year period. s up to 19.5% from the zero year
    of operation until 10 years of the operation. In addition, the time propagation delay increased as year
    increased when the technology nodes smaller. The finding is important for understanding reliability
    issues related to advanced technology nodes in CMOS circuits study.
    Matched MeSH terms: Temperature
  8. Fulltext Comparison between conventional and alternative peeling methods on peeling efficiencies of Malaysian ‘Chok Anan’ mango (Mangifera indica L.) fruit
    Mohamad, N.S., Sulaiman, R., Lai, O.M., Hussain, N.
    International Food Research Journal, 2017;24(5):1934-1940.
    MyJurnal
    Fruit industries require convenient peeling method, especially during puree processing to prevent deterioration of fruit quality and product loss. Therefore, manual, chemical (sodium hydroxide/NaOH) and enzymatic (Pectinex Ultra SP-L) peeling methods were compared to determine the peeling efficiencies of ‘Chok Anan’ mangoes. The effect of different peeling parameters (concentrations [chemical peeling: 1.6-7.3% of 0.4M-1.83M; enzymatic peeling: 0.005-0.095%], temperatures [chemical peeling: 80-95oC; enzymatic peeling: 25-40°C], and duration of soaking [chemical peeling: 5-10 min; enzymatic peeling: 30-120 min]) were evaluated for peeling yield, peeling time, absorption of chemical and enzyme solution, the penetration depth of NaOH and enzyme activities (reducing sugar analysis). The enzymatic peeling had significantly (p0.05) in peeling yield (>86%), but there was significant (p
    Matched MeSH terms: Temperature
  9. Coarsening Dynamics of an Isotropic Ferromagnetic Superfluid
    Williamson LA, Blakie PB
    Phys Rev Lett, 2017 Dec 22;119(25):255301.
    PMID: 29303307 DOI: 10.1103/PhysRevLett.119.255301
    In zero magnetic field the ground-state manifold of a ferromagnetic spin-1 condensate is SO(3) and exhibits Z_{2} vortices as topological defects. We investigate the phase-ordering dynamics of this system after being quenched into this ferromagnetic phase from a zero-temperature unmagnetized phase. Following the quench, we observe the ordering of both magnetic and gauge domains. We find that these domains grow diffusively, i.e., with domain size L(t)∼t^{1/2}, and exhibit dynamic scale invariance. The coarsening dynamics progresses as Z_{2} vortices annihilate; however, we find that at finite energy a number of these vortices persist in small clumps without influencing magnetic or gauge order. We consider the influence of a small nonzero magnetic field, which reduces the ground-state symmetry, and show that this sets a critical length scale such that when the domains reach this size the system dynamically transitions in order parameter and scaling behavior from an isotropic to an anisotropic ferromagnetic superfluid.
    Matched MeSH terms: Temperature
  10. Formation of 3-MCPD and glycidyl esters in biscuits produced using soybean oil-based diacylglycerol stearin-shortening blends: Impacts of different baking temperatures and blending ratios
    Shafika Abdul Kadir N, Khor YP, Lee YJ, Lan D, Qi S, Wang Y, et al.
    Food Res Int, 2022 Dec;162(Pt B):112055.
    PMID: 36461315 DOI: 10.1016/j.foodres.2022.112055
    Diacylglycerol (DAG) is commonly known as one of the precursors for 3-monochloropropane-1,2-diol esters (3-MCPDE) and glycidyl esters (GE) formation. Besides, 3-MCPDE and GE are heat-induced contaminants which can be formed in fat-containing baked products during the baking process. This study attempted to replace the conventional palm-based shortening (SH) with a healthier fat, namely soybean oil-based diacylglycerol stearin (SDAG) in producing biscuits. The effects of different baking temperatures (200, 210 and 220 °C) and SDAG:SH fat blend ratios (0:100, 60:40 (D64S), 80:20 (D82S), 100:0, w/w) towards the biscuits' physical properties were evaluated. Moreover, the oxidative stability, 3-MCPDPE and GE formation in the fats extracted from the biscuits were also investigated. SDAG-produced biscuit showed slight reductions in the spread ratio compared to the SH-produced biscuit. The elevated baking temperatures resulted in biscuits with increased hardness and low moisture content. Pure SDAG and the other fat blends exhibited significant (p 
    Matched MeSH terms: Temperature
  11. Fulltext Community surveillance of Aedes albopictus associated with Wolbachia detection in low-rise residential areas in Selangor, Malaysia
    Roslan MA, Ngui R, Vythilingam I, Wan Sulaiman WY
    J Vector Ecol, 2022 Dec;47(2):142-152.
    PMID: 36314668 DOI: 10.52707/1081-1710-47.2.142
    The study assessed the distribution of Malaysian Ae. albopictus adults associated with Wolbachia detection in low-rise residential areas using a modified sticky ovitrap (MSO). The relationship between Ae. albopictus and climatological parameters were also determined. Fifty-two weeks of surveillance using 273 MSOs were conducted in four installation areas of eleven sampling sites. Specimens were subjected to PCR using wsp-specific primers for Wolbachia detection. The relationship between climatological parameters and Ae. albopictus captured were analyzed using Spearman rank correlation coefficient test. The majority of Ae. albopictus were captured in residential houses (87%), followed by playgrounds or parks (11.5%), guardhouses (1%), and community halls (0.5%). Most of the specimens (92%) were superinfected with wAlbA and wAlbB strains. A positive correlation with no significant association was found for rainfall (r = 0.015, P = 0.072), relative humidity (r = 0.005, P = 0.526), minimum temperature (r = 0.005, P = 0.516), and mean temperature (r = 0.003, P = 0.689). MSO effectively captured a high number of Ae. albopictus that was determined to be the predominant mosquito species found in low-rise residential areas. The adult collection is not only influenced by climatological parameters but also by other factors, including environmental conditions and general sanitation status.
    Matched MeSH terms: Temperature
  12. Fulltext Exposure-lag response of air temperature on COVID-19 incidence in twelve Italian cities: A meta-analysis
    Fong FC, Smith DR
    Environ Res, 2022 Sep;212(Pt A):113099.
    PMID: 35305982 DOI: 10.1016/j.envres.2022.113099
    The exposure-lag response of air temperature on daily COVID-19 incidence is unclear and there have been concerns regarding the robustness of previous studies. Here we present an analysis of high spatial and temporal resolution using the distributed lag non-linear modelling (DLNM) framework. Utilising nearly two years' worth of data, we fit statistical models to twelve Italian cities to quantify the delayed effect of air temperature on daily COVID-19 incidence, accounting for several categories of potential confounders (meteorological, air quality and non-pharmaceutical interventions). Coefficients and covariance matrices for the temperature term were then synthesised using random effects meta-analysis to yield pooled estimates of the exposure-lag response with effects presented as the relative risk (RR) and cumulative RR (RRcum). The cumulative exposure response curve was non-linear, with peak risk at 15.1 °C and declining risk at progressively lower and higher temperatures. The lowest RRcum at 0.2 °C is 0.72 [0.56,0.91] times that of the highest risk. Due to this non-linearity, the shape of the lag response curve necessarily varied by temperature. This work suggests that on a given day, air temperature approximately 15 °C maximises the incidence of COVID-19, with the effects distributed in the subsequent ten days or more.
    Matched MeSH terms: Temperature
  13. Fulltext A systematic review and meta-analysis of the effects of temperature on the development and survival of the Aedes mosquito
    Nik Abdull Halim NMH, Che Dom N, Dapari R, Salim H, Precha N
    Front Public Health, 2022;10:1074028.
    PMID: 36600940 DOI: 10.3389/fpubh.2022.1074028
    INTRODUCTION: The Aedes mosquito species, which are the vectors for the transmission of the dengue virus (DENV) to humans, are becoming increasingly susceptible to the formidable effects of influential factors, especially temperature. However, there are still very few studies that have systematically reviewed the existing literature. Hence, in the present study, a systematic literature review and meta-analysis was conducted into the effects of temperature on dengue vectors.

    METHOD: Several research methodologies were incorporated into the current study, and a review was carried out using PRISMA as a guide. The publications for this study were chosen from two prominent databases, Scopus and Web of Science. All of the studies were assessed, reviewed, and evaluated independently by two reviewers. The meta-analysis tool, Review Manager (RevMan Copenhagen Version 5.4.1), was used to record the extracted data for the meta-analysis. Moran's I 2 and a funnel plot were utilized to measure heterogeneity, and publication bias was investigated. A 95% confidence interval (CI) and overall risk difference (RD) were estimated using a random-effects model.

    RESULT AND DISCUSSION: As a consequence of the search efforts, a total of 46 articles were selected for inclusion in the systematic review and meta-analysis. This review was divided into five major themes, based on a thematic analysis: (i) hatching rate, (ii) development time, (iii) longevity, (iv) survival rate, and (v) wing morphology. In addition, the development time, survival rate, and wing morphology revealed significantly higher risk differences between the maximum and minimum temperatures (RD: 0.26, 95% CI: 0.16, 0.36; p = < 0.00001; RD: 0.10, 95% CI: 0.05, 0.14; p < 0.0001; and RD: 0.07, 95% CI: 0.02, 0.12; p = 0.006, respectively). This study makes several substantial contributions to the body of knowledge and to practical applications. Finally, a number of recommendations are made at the conclusion of this research for the future reference of researchers.

    Matched MeSH terms: Temperature
  14. Reduction in environmental CO2 by utilization of optimized energy scheme for power and fresh water generations based on different uses of biomass energy
    Hai T, Ali MA, Alizadeh A, Almojil SF, Almohana AI, Alali AF
    Chemosphere, 2023 Apr;319:137847.
    PMID: 36657576 DOI: 10.1016/j.chemosphere.2023.137847
    Renewable energy sources are undoubtedly necessary, considering global electricity demand is expected to rise dramatically in the coming years. This research looks at a unique multi-generation plant from the perspectives of exergy, energy, and economics; also, an environmental evaluation is performed to estimate the systems' CO2 emissions. The unit is made up of a biomass digester and gasifier, a Multi effect Desalination unit, and a supercritical CO2 (SCO2) cycle. In this study, two methods for using biomass are considered: the first is using synthesis gas generated by the gasifier, and the second is utilizing a digester to generate biogas. A comprehensive parametric study is performed on the designed energy unit to assess the influence of compressor pressure ratio, Gas turbine inlet temperature, supercritical CO2 cycle pressure ratio, and the number of effects of multi-effect distillation on the system performance. Furthermore, the exergy study revealed that the exergy destruction in the digestion unit was 11,337 kW, which was greater than the exergy destruction in the gasification unit, which was 9629. Finally, when compared to the gasifier, the amount of exergy efficiency, net output power, and freshwater production in the digester was greater.
    Matched MeSH terms: Temperature
  15. Leptospirosis modelling using hydrometeorological indices and random forest machine learning
    Jayaramu V, Zulkafli Z, De Stercke S, Buytaert W, Rahmat F, Abdul Rahman RZ, et al.
    Int J Biometeorol, 2023 Mar;67(3):423-437.
    PMID: 36719482 DOI: 10.1007/s00484-022-02422-y
    Leptospirosis is a zoonosis that has been linked to hydrometeorological variability. Hydrometeorological averages and extremes have been used before as drivers in the statistical prediction of disease. However, their importance and predictive capacity are still little known. In this study, the use of a random forest classifier was explored to analyze the relative importance of hydrometeorological indices in developing the leptospirosis model and to evaluate the performance of models based on the type of indices used, using case data from three districts in Kelantan, Malaysia, that experience annual monsoonal rainfall and flooding. First, hydrometeorological data including rainfall, streamflow, water level, relative humidity, and temperature were transformed into 164 weekly average and extreme indices in accordance with the Expert Team on Climate Change Detection and Indices (ETCCDI). Then, weekly case occurrences were classified into binary classes "high" and "low" based on an average threshold. Seventeen models based on "average," "extreme," and "mixed" indices were trained by optimizing the feature subsets based on the model computed mean decrease Gini (MDG) scores. The variable importance was assessed through cross-correlation analysis and the MDG score. The average and extreme models showed similar prediction accuracy ranges (61.5-76.1% and 72.3-77.0%) while the mixed models showed an improvement (71.7-82.6% prediction accuracy). An extreme model was the most sensitive while an average model was the most specific. The time lag associated with the driving indices agreed with the seasonality of the monsoon. The rainfall variable (extreme) was the most important in classifying the leptospirosis occurrence while streamflow was the least important despite showing higher correlations with leptospirosis.
    Matched MeSH terms: Temperature
  16. Thermocatalytic conversion of wood-plastic composite over HZSM-5 catalysts
    Seo J, Kim H, Jeon S, Valizadeh S, Khani Y, Jeon BH, et al.
    Bioresour Technol, 2023 Apr;373:128702.
    PMID: 36740100 DOI: 10.1016/j.biortech.2023.128702
    Air gasification of the Wood-Plastic Composite (WPC) was performed over Ni-loaded HZSM-5 catalysts to generate H2-rich gas. Increasing SiO2/Al2O3 ratio (SAR) of HZSM-5 adversely affected catalytic activity, where the highest gas yield (51.38 wt%) and H2 selectivity (27.01 vol%) were acquired using 20 %Ni/HZSM-5(30) than those produced over 20 %Ni/HZSM-5(80) and 20 %Ni/HZSM-5(280). Reducing SAR was also favorably conducive to increasing the acyclic at the expense of cyclic compounds in oil products. These phenomena are attributed to enhanced acid strength and Ni dispersion of 20 %Ni/HZSM-5(30) catalyst. Moreover, catalytic activity in the terms of gas yield and H2 selectivity enhanced with growing Ni loading to 20 %. Also, the addition of promoters (Cu and Ca) to 20 %Ni/HZSM-5(30) boosted the catalytic efficiency for H2-rich gas generation. Raising temperature indicated a positive relevance with the gas yield and H2 selectivity. WPC valorization via gasification technology would be an outstanding outlook in the terms of a waste-to-energy platform.
    Matched MeSH terms: Temperature
  17. Knotting terminal ends of mutant T1 lipase with disulfide bond improved structure rigidity and stability
    Hamdan SH, Maiangwa J, Nezhad NG, Ali MSM, Normi YM, Shariff FM, et al.
    Appl Microbiol Biotechnol, 2023 Mar;107(5-6):1673-1686.
    PMID: 36752811 DOI: 10.1007/s00253-023-12396-5
    Lipase biocatalysts offer unique properties which are often impaired by low thermal and methanol stability. In this study, the rational design was employed to engineer a disulfide bond in the protein structure of Geobacillus zalihae T1 lipase in order to improve its stability. The selection of targeted disulfide bond sites was based on analysis of protein spatial configuration and change of Gibbs free energy. Two mutation points (S2C and A384C) were generated to rigidify the N-terminal and C-terminal regions of T1 lipase. The results showed the mutant 2DC lipase improved methanol stability from 35 to 40% (v/v) after 30 min of pre-incubation. Enhancement in thermostability for the mutant 2DC lipase at 70 °C and 75 °C showed higher half-life at 70 °C and 75 °C for 30 min and 52 min, respectively. The mutant 2DC lipase maintained the same optimum temperature (70 °C) as T1 lipase, while thermally induced unfolding showed the mutant maintained higher rigidity. The kcat/Km values demonstrated a relatively small difference between the T1 lipase (WT) and 2DC lipase (mutant). The kcat/Km (s-1 mM-1) of the T1 and 2DC showed values of 13,043 ± 224 and 13,047 ± 312, respectively. X-ray diffraction of 2DC lipase crystal structure with a resolution of 2.04 Å revealed that the introduced single disulfide bond did not lower initial structural interactions within the residues. Enhanced methanol and thermal stability are suggested to be strongly related to the newly disulfide bridge formation and the enhanced compactness and rigidity of the mutant structure. KEY POINTS: • Protein engineering via rational design revealed relative improved enzymatic performance. • The presence of disulfide bond impacts on the rigidity and structural function of proteins. • X-ray crystallography reveals structural changes accompanying protein modification.
    Matched MeSH terms: Temperature
  18. High pressure CO2 adsorption onto Malaysian Mukah-Balingian coals: Adsorption isotherms, thermodynamic and kinetic investigations
    Abunowara M, Bustam MA, Sufian S, Babar M, Eldemerdash U, Mukhtar A, et al.
    Environ Res, 2023 Feb 01;218:114905.
    PMID: 36442522 DOI: 10.1016/j.envres.2022.114905
    CO2 sequestration into coalbed seams is one of the practical routes for mitigating CO2 emissions. The adsorption mechanisms of CO2 onto Malaysian coals, however, are not yet investigated. In this research CO2 adsorption isotherms were first performed on dry and wet Mukah-Balingian coal samples at temperatures ranging from 300 to 348 K and pressures up to 6 MPa using volumetric technique. The dry S1 coal showed the highest CO2 adsorption capacity of 1.3 mmol g-1, at 300 K and 6 MPa among the other coal samples. The experimental results of CO2 adsorption were investigated using adsorption isotherms, thermodynamics, and kinetic models. Nonlinear analysis has been employed to investigate the data of CO2 adsorption onto coal samples via three parameter isotherm equilibrium models, namely Redlich Peterson, Koble Corrigan, Toth, Sips, and Hill, and four parameter equilibrium model, namely Jensen Seaton. The results of adsorption isotherm suggested that the Jensen Seaton model described the experimental data well. Gibb's free energy change values are negative, suggesting that CO2 adsorption onto the coal occurred randomly. Enthalpy change values in the negative range established that CO2 adsorption onto coal is an exothermic mechanism. Webber's pore-diffusion model, in particular, demonstrated that pore-diffusion was the main controlling stage in CO2 adsorption onto coal matrix. The activation energy of the coals was calculated to be below -13 kJ mol-1, indicating that adsorption of CO2 onto coals occurred through physisorption. The results demonstrate that CO2 adsorption onto coal matrix is favorable, spontaneous, and the adsorbed CO2 molecules accumulate more onto coal matrix. The observations of this investigation have significant implications for a more accurate measurement of CO2 injection into Malaysian coalbed seams.
    Matched MeSH terms: Temperature
  19. Multi-objective operation optimization of spent coffee ground torrefaction for carbon-neutral biochar production
    Chen WH, Lee KT, Ho KY, Culaba AB, Ashokkumar V, Juan CJ
    Bioresour Technol, 2023 Feb;370:128584.
    PMID: 36610482 DOI: 10.1016/j.biortech.2023.128584
    Many energy-intensive processes are employed to enhance biomass fuel properties to overcome the difficulties in utilizing biomass as fuel. Therefore, energy conservation during these processes is crucial for realizing a circular bioeconomy. This study develops a newly devised method to evaluate SCG biochars' higher heating value (HHV) and predict moisture content from power consumption. It is found that the increasing rates of HHV immediately follow decreases in power consumption, which could be used to determine the pretreatment time for energy conservation. The non-dominated sorting genetic algorithm II (NSGA-II) maximizes SCG biochar's HHV while minimizing energy consumption. The results show that producing SCG biochar with 23.98 MJ∙kg-1 HHV requires 20.042 MJ∙kg-1, using a torrefaction temperature of 244 °C and torrefaction time of 27 min and 43 sec. Every kilogram of biochar with an energy yield of 85.93 % is estimated to cost NT$ 12.21.
    Matched MeSH terms: Temperature
  20. Carbonized rice husk coated solar absorber for clean water generation from seawater with a solar still
    Karen WMJ, Wong CY, Wang Z, Liew WYH, Melvin GJH
    Environ Technol, 2023 Jan;44(3):326-333.
    PMID: 34407722 DOI: 10.1080/09593330.2021.1970820
    This study demonstrated the generation of clean water from seawater collected at the beach coast in Universiti Malaysia Sabah, Malaysia, with carbonized rice husk coated melamine sponge as solar absorber by a solar still. Melamine sponge was utilized as a seawater transportation medium since its porous structure is excellent in channelling the seawater. Whereas carbonized rice husk was used as the photothermal conversion material for its efficient heat absorption due to its black colour and porous structure. Implementing air gap between the seawater body and solar absorber, and restricted water pathway assisted in localizing heat on the top surface of the solar absorber. Clean water was generated under direct solar radiation during the day at an open space with average solar intensity around 1.1∼1.2 kW/m2 (slightly higher than 1 sun) for about 4 h. Efficiency of the solar absorber was calculated, while the quality of the generated clean water was observed in terms of salinity and pH value. Insulated solar still with carbon-coated sponge showed the highest efficiency at about 54.74%. Salinity of the collected clean water significantly reduced to consumable level which was approximately 55 ppm, and the pH value at about 6.73 where it was within the safe limit of the drinkable water pH.
    Matched MeSH terms: Hot Temperature
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