Influence Of Temperature Research Articles

Influence of growth temperature on the structural and optical characteristics of PbZnS thin films

Ternary thin films have garnered significant attention due to their adjustable band gap characteristics, making them suitable for many applications. In this research, we examined the structural and optical characteristics of PbZnS thin films fabricated onto glass substrates employing the spray pyrolysis techniuqe. The films were fabricated at different temperatures ranging from 300 to 400°C. X-ray diffraction (XRD) analysis indicated that all films displayed a cubic structure with a preferred orientation along the (200) plane. From the analysis of XRD peaks, it was observed that the crystal structure initially improved with increasing temperature but then began to degrade. These films demonstrated strong absorption in the range of 350–1600 nm. The optical bandgap (Eg) values, calculated based on the relationship between the absorption coefficient and photon energy, showed slight variations around 2 eV. Notably, the band gap decreased with growth temperatures up to 350°C, then increased at higher temperatures. These fluctuations are attributed to factors such as thermal expansion, strain, defects, surface/interface effects, and changes in doping or composition.

Effect of aging state on microstructure and properties of heat affected zone in Al-Mg-Si-Cu alloy welded joints

The softening of the heat affected zone (HAZ) remains a significant challenge in fusion welding of novel Al-Mg-Si-Cu alloy, and the underlying mechanisms vary across different aging states. However, limited research has been conducted on this topic. Therefore, this study investigates the influence of various aging states on the microstructure and mechanical properties within the HAZ of welded joints by selecting extrusions treated with T4, T5, and T6 heat treatments. The results indicate that the increase in hardness of HAZ I is attributed to solid solution strengthening. In the HAZ I, the precipitated phases are mostly dissolved into the matrix under the influence of a peak temperature of 464.6 °C, and no residual precipitated phase is detected in T4 and T5 alloy joints, while some undissolved Q phase is observed in T6 alloy joint. The decrease in hardness of HAZ Ⅱ is attributed to the limited precipitation of coarse β" and Q' phases for the T4 alloy welded joints, which weakens the solid solution strengthening. However, the softening mechanisms in the HAZ Ⅱ of the T5 and T6 alloy joints are ascribed to the dissolution of β" and subsequent precipitation of Q' and Q phases. HAZ Ⅲ, close to the base metal, exhibits a lesser degree of influence and thus experiences a gradual recovery in hardness. This study can provide theoretical guidance for the exploration of high-strength, heat-resistant aluminum alloys.

Enhancing the quantum yield and electrochemical properties of carbon quantum dots via optimized hydrothermal treatment using cellulose nanocrystals as precursors

Carbon quantum dots (CQDs) are receiving increasing attention due to their tunable redox activity, abundant surface functional groups, and excellent aqueous dispersion. However, their low quantum yield remains a significant impediment to their synthesis and practical application. In the present work, cellulose nanocrystals (CNCs) were utilized as precursors for the optimized hydrothermal synthesis of CQDs. Subsequently, the synthesized CQDs were electrodeposited onto a carbon-coated surface. The influence of hydrothermal temperature and time on the quantum yield and electrochemical properties of CQDs was systematically explored. The successful synthesis of CQDs displayed an average particle size of 5 nm, approximately. The quantum yield was enhanced from 14.35 % to 23.7 % as the hydrothermal temperature increased from 180 °C to 230 °C. Additionally, the electrochemical properties of the composite films were investigated. Electrochemical assessments demonstrated an increase in specific capacitance from 60.4 mF·cm−2 to 65.2 mF·cm−2 with an elevation in temperature from 180 °C to 210 °C. Remarkably, the CQDs displayed higher e CQDs, showcasing their substantial potential for supercapacitor applications.

The influence of pre-sintering temperature on the structural, magnetic, and dielectric properties of Sr0.67La0.33Fe11.7Zn0.1Co0.2O19 ferrite

The present study explores the impact of varying heat treatment temperatures on the magnetic properties, structural configuration and dielectric characteristics of Sr0.67La0.33Fe11.7Zn0.1Co0.2O19 ferrite. M-type ferrite was synthesized using the traditional solid-state method, with thermal treatment temperatures incrementally increasing from 1230 °C to 1310 °C. Pure M-phase strontium ferrite was achieved at temperatures above 1250 °C. The ideal pre-sintering temperature was identified as 1270 °C, where several factors coalesced to enhance the magnetic properties, including the completion of the solid-state reaction and the diminution of the easily magnetized c-axis, which together fostered the intensification of the superexchange interaction. At this temperature, the magnetic properties reached their zenith, with a saturation magnetization (Ms) of 84.81 emu/g, a remanence (Br) of 419 mT, and a coercivity (Hcj) of 3301 Oe. Additionally, the dielectric constant was significantly high at low frequencies but rapidly declined with increasing frequency, achieving its optimal performance at 1270 °C.

Influence of Salt and Temperature on the Rheological and Filtration Properties of Cellulose Nanofiber/Bentonite Water-Based Drilling Fluids

Influence of Salt and Temperature on the Rheological and Filtration Properties of Cellulose Nanofiber/Bentonite Water-Based Drilling Fluids

Load-bearing characteristics of surface conductor in deepwater gas hydrate formations

The surface conductor is the first structural casing in deepwater natural gas hydrate (NGH) development, bearing the top load while suspending the casings of various layers. NGH decomposition leads to formation settlement, changing the mechanical properties of the formation and reducing the bearing capacity of the surface conductor, threatening the safety and stability of the wellhead. Understanding the bearing characteristics of the surface conductor in the hydrate formation can guide the safe drilling operation in the field. By introducing the negative skin friction theory of pile foundations and based on conventional bearing capacity models, a method for calculating the bearing capacity of surface conductors in NGH formations was developed. Using an NGH drilling simulation apparatus, the accuracy of the bearing capacity theoretical model was verified, empirical coefficients under different conditions were obtained, and the influence of soil parameters, hydrate saturation, and decomposition temperature on the bearing capacity of surface conductors was quantified. The results indicated that compared to clay, sandy soils have higher porosity and significantly weakened strength after the decomposition of NGH; when the hydrate saturation in the formation is 20%, the reduction in bearing capacity of the surface conductor in sand exceeds 30%, and in clay soils, it decreases by 25% after complete decomposition of NGH; as the hydrate saturation increases, the reduction in the bearing capacity of surface conductors after decomposition becomes more significant. Verified through Experimentation, the error of the hydrate-bearing strata-bearing capacity model is around 10%. For short-term test production operations of NGH in water, the design depth for surface conductors is around 100 meters. These research results can provide a scientific theoretical basis for the design of conductor depth below the mud， and reduce operational risks.

Interactions between SDBS and Hydrilla verticillata − epiphytic biofilm in wetland receiving STPs effluents: Nutrients removal and epiphytic microbial assembly

The fate and effects of sodium dodecyl benzene sulfonate (SDBS) in sewage treatment plants (STPs) effluents on nutrients and submerged macrophytes are far from clear in wetlands. This study conducted a 24-day experiment to investigate changes in nutrients and epiphytic biofilm of Hydrilla verticillata in wetlands receiving effluents with 0.5, 2 and 5 mg L−1 SDBS. The decrease of SDBS in overlying water followed pseudo-first-order kinetic equation, with over 80 % of SDBS removal achieved. 2 and 5 mg L−1 SDBS decreased nutrient removal efficiency, induced oxidative stress response and damaged cells of H. verticillata. SDBS altered bacterial and eukaryotic community diversity. 0.5 mg L−1 SDBS can promote carbon fixation and methane oxidation of microorganisms. Network analysis revealed that 0.5 mg L−1 SDBS decreased the stability of epiphytic ecosystems. Mantel tests indicated significant influences of SDBS, temperature, and total nitrogen on epiphytic microbial communities.

Non-Arrhenius grain growth in SrTiO3: Impact on grain boundary conductivity and segregation

In this study, a correlation between the conductivity, space charge layers, solute drag and non-Arrhenius grain growth in SrTiO3 was investigated. Strontium titante is known for its non-Arrhenius grain growth where grain growth rates decrease by orders of magnitude with increasing temperatures between 1350°C and 1425°C. Here, undoped SrTiO3 was sintered and annealed at temperatures below and above the grain growth transition. The influence of the annealing temperature and time on the conductivity and space charge layers at grain boundaries (GBs) in SrTiO3 was investigated by electrochemical impedance spectroscopy (EIS). STEM-EDS analysis indicates the presence of GBs with qualitative different cationic segregation in SrTiO3. A distortion of the GB semi-circle in the impedance plots was found which was attributed to the presence of multiple GB types with different electric properties and space charge layers. The presence of two GB types as indicated by impedance analysis corresponds well with previous results, where solute drag and segregation was supposed to cause the non-Arrhenius grain growth behavior of SrTiO3.

Spent Coffee Ground Biochar for phosphate adsorption in water: Influence of pyrolysis temperature and iron-coating activation method

Spent Coffee Ground Biochar for phosphate adsorption in water: Influence of pyrolysis temperature and iron-coating activation method

The influence of pure compounds’ parameters on the phase behaviour of carbon dioxide + 1-hexanol binary system

New vapour–liquid–liquid and vapour–liquid equilibrium data to complement the existing ones are measured at six temperatures (308.15 K to 383.15 K) and at pressures up to 182.9 K using an analytic-static method with phases sampling via special valves (“AnTVisVarCap”, as defined by Prof. Ralf Dohrn and co-workers) for the carbon dioxide (1) + 1-hexanol (2) binary system. Four out of the six isotherm reported here are measured for the first time. The main component of the high-pressure setup is a 60 cm3 visual cell.The new isotherms are compared with the available literature which is also reviewed and analysed. It should be noted that among the data already published, only one other research group reported the compositions of both phases at equilibrium, as we did previously by using another experimental method. The new and literature data were modelled with Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) equations of state based on a semi-predictive procedure to reproduce as well as possible the minimum and the maximum of the critical curve(s) using one set of binary interaction parameters. The influence of critical data and acentric factors of pure components on the phase behaviour of their binary system is discussed. Although the values of the critical pressures and acentric factors of pure substances are not very different in the database we used, the models predict type III or IV phase behaviour with the same set of binary interaction parameters. This sensitivity, which was not observed for other systems we studied, could be explained by the alcohol structure and high asymmetry of the system. Therefore, we analysed in more depth the influence of the critical temperatures and pressures, as well as the acentric factors of carbon dioxide and 1-hexanol and exemplified for one temperature located above the system UCEP's temperature.

Temperature-driven structural and morphological changes in nitrogen-doped carbon nanofibers synthesized via LaNi5Pt1.0 intermetallic catalyst

In the modern world, heteroatom-doped carbon allotropes play a pivotal role in both fundamental and applied nanotechnology advancements. Due to their exceptional electrical, thermal, chemical, and mechanical properties, which are strongly influenced by the synthesis method, they are highly suitable for a wide range of applications. Catalytic chemical vapor deposition (CCVD) is the leading synthesis technique for producing nitrogen-doped carbon nanofibers (NCNFs) with controlled morphology and structural properties. This report emphasizes the significant influence of reaction temperature on synthesizing CNFs using a LaNi5Pt1.0 intermetallic catalyst. The LaNi5Pt1.0 catalysts prepared through an arc melting process, acted as templates for the catalytic conversion of carbon precursors into solid material via the CCVD method. Additionally, this study provides valuable insights into the temperature-dependent phase transitions and carbon diffusion during the synthesis of NCNFs. The surface segregation mechanism driving phase changes in the catalyst plays a crucial role in the active formation of NCNFs. The segregation of metallic nickel into the CNF structure significantly impacts N-CNF formation, highlighting the intricate dynamics involved in CNF synthesis. Overall, these findings offer a deeper understanding of the synthesis process and the structural evolution of N-CNFs across different growth temperatures.

Influence of Annealing Temperature on the OER Activity of NiO(111) Nanosheets Prepared via Microwave and Solvothermal Synthesis Approaches.

Earth-abundant transition metal oxides are promising alternatives to precious metal oxides as electrocatalysts for the oxygen evolution reaction (OER) and are intensively investigated for alkaline water electrolysis. OER electrocatalysis, like most other catalytic reactions, is surface-initiated, and the catalyst performance is fundamentally determined by the surface properties. Most transition metal oxide catalysts show OER activities that depend on the predominantly exposed crystal facets/surface structure. Therefore, the design of synthetic strategies to obtain the most active crystal facets is of significant research interest. In this work, rock salt NiO OER catalysts with (111) predominantly exposed facets were synthesized by a solvothermal (ST) method either heated under supercritical or microwave-assisted (MW) conditions. Particular emphasis was placed on the influence of the post annealing temperature on the structural configuration and OER activity to compare their catalytic performances. The as-prepared electrocatalysts are pure α-Ni hydroxides which were converted to rock salt NiO (111) nanosheets with hexagonal pores after heat treatment at different temperatures. The OER activity of the electrodes has been evaluated in 0.1 M KOH using geometric and intrinsic current densities via normalization by the disk area and BET area, respectively. The lowest overpotential at a geometric current density of 10 mA/cm2 is found for samples pretreated by heating between 400 and 500 °C with a catalyst loading of 115 μg/cm2. Despite the very similar nature of the catalysts obtained from the two methods, the ST electrodes show a higher geometric and intrinsic current density for 500 °C pretreatment. The MW electrodes, however, achieve an optimal geometric current density for 400 °C pretreatment, while their intrinsic current density requires pretreatment over 600 °C. Interestingly, pretreated electrodes show consistently higher OER activity as compared to the poorly crystalline/less ordered hydroxide as-prepared electrocatalysts. Thus, our study highlights the importance of the synthesis method and pretreatment at an optimal temperature.

Study on Shutter Heating Performance of Gas Turbine Intake System

Abstract Aiming at the anti-icing and de-icing requirements of gas turbine intake system, study the heating performance of a typical shutter vane, and compares and analyzes the influence of different ambient temperature and different electrothermal pipe heat generation rate on vane temperature distribution and heat transfer characteristics. The results show that the air convection at different positions on the blade surface of the louver leads to the difference in the temperature distribution of the upper and lower surfaces of the blade, as well as the leading edge and trailing edge of the blade, and the leading edge of the blade, as the area with the lowest overall temperature distribution of the blade, should be focused on in the design of anti-icing and de-icing systems. Increasing the heat production rate of the electric heating tube, there is more heat flow near the midline of the blade, which makes the temperature rise at this position the highest, and it is necessary to pay attention to the energy waste and blade damage caused by local overheating of the blade. Therefore, when the ambient temperature increases from 245.15 K to 318.15 K, the leaf temperature increases from 248.73 K to 322.74 K, and the temperature rise also increases from 3.58 K to 4.59 K. The electrothermal technology can be used to the anti-icing and de-icing of the intake system shutters on the basis of choosing the heat generation rate of the electrothermal tube reasonably.

Low-velocity impact damage characteristics of flax/glass epoxy hybrid laminates on the influence of different temperatures: Experimental and numerical analysis

Low-velocity impact damage characteristics of flax/glass epoxy hybrid laminates on the influence of different temperatures: Experimental and numerical analysis

The Annealing Temperature Effect Enhances the Structural and Optical Parameters of Bi2Te3 Thermally Evaporated Thin Films

The current work investigates the influence of the annealing temperature (373, 473 K) on the structural and optical properties of Bi2Te3 thin films produced by the thermal evaporation technique. The crystal structure of samples is examined using an X-ray diffraction, indicating that Bi2Te3 thin films have a Rhombohedral structure with space group R-3m. The crystallite size (D) increased from 10.85 to 14.46 nm by increasing the annealing temperature. Additionally, increasing the annealing temperature reduces the micro-strain and the dislocation density from (3.33 × 10−3 to 2.5 × 10−3) and (8.49 × 1015 to 4.78 × 1015) Lines / m 2 , respectively. These micro-strain and dislocation density reductions refer to the crystallinity enhancement of sample Bi2Te3 thin films. The transmittance and reflectance spectra were measured using an Fourier transform infrared spectrometer. All samples reveal direct and indirect transition types and both direct and indirect optical energy gap decreased with increased annealing temperature from (0.325 to 0.29 eV) and (0.24 to 0.274 eV), respectively. From transmittance and reflectance data, the refractive index is calculated. These results reveal the refractive index decreasing as temperature annealing increased from (2.45–1.79) at 3250 nm. Other optical parameters such as absorption index, dielectric constant, energy loss function, and optical conductivity were estimated.

Influence of Elevated Temperature and Oxygen on the Capture of Radioactive Iodine by Silver Functionalized Silica Aerogel

Reprocessing is considered a competent strategy for spent nuclear fuel management, yet radioiodine (129I) is emitted in reprocessing off-gas as a hazardous byproduct. Silver functionalized silica aerogel (Ag0-aerogel), a promising iodine capture material, experiences a reduction in its capacity after prolonged exposure to off-gas components at elevated temperatures, a phenomenon termed as aging. To fully understand this process, we isolated the contribution of each aging factor, exposing Ag0-aerogel samples to N2 and dry air gas streams, respectively, at 150°C for different time periods. Aged samples were loaded with I2 to examine the capacity change and comprehensively characterized to investigate the evolution of their properties. Results show that temperature alone did not alter Ag0-aerogel’s capacity but triggered Ag0 nanoparticles sintering and generated organic sulfur species. The presence of O2 reduced the capacity by ∼20%, causing (i) formation of silver sulfide (Ag2S) crystals and (ii) oxidation of Ag-thiolate (Ag-S-r) to Ag sulfonate (Ag-SO3-r). Given that Ag2S readily adsorbs I2, the formation of Ag-SO3-r is the major inhibitor for iodine adsorption. This hypothesis was supported by density functional theory (DFT) simulations. These findings unraveled key mechanisms of Ag0-aerogel aging, which are useful in the development of materials that withstand realistic spent-nuclear-fuel-reprocessing off-gas conditions.

Influence of elevated temperature on the interfacial adhesion properties of cement composites reinforced with recycled coconut fiber

Magnesium phosphate cement (MPC) is the preferred material for rapid repair due to its rapid setting and early strength properties. However, its inherent brittleness renders it less suitable for use in assembled building nodes. To address the brittleness of MPC, coconut fiber (CF), a natural fiber known for its toughness, is often employed as a reinforcement. However, CF-MPC encounter difficulties in high-temperature settings, such as fire emergencies, which may compromise the interfacial bonding properties of this materials. This paper presents an investigation into the interfacial bonding properties of CF-MPC at elevated temperatures. The study employed microscopic analysis to observe the material changes of CF at elevated temperatures, evaluated the mechanical property changes by means of Fiber Tensile Test, and assessed the interfacial bonding performance by means of Fiber Drawing Test between CF and MPC. The findings indicated that as the temperature increased, the carbonized residue of the CF gradually decomposed, resulting in a notable decline in mechanical strength. Upon exceeding 400°C, the carbonization of CF was complete, resulting in the loss of its mechanical properties. Besides the results also demonstrated that the interfacial bond strength of CF-MPC at a burial depth of 7.5 mm reaches its maximum value of 2.14 MPa at 20°C. As the temperature rises to 200°C, the interfacial bond strength at a burial depth of 12.5 mm reaches its maximum value of 1.08 MPa at this temperature. The findings of this study are conducive to promoting the application of CF-MPC at high temperatures and provide a theoretical basis for the subsequent optimization of this material.

Weight loss and electrochemical measurements of aluminum corrosion in diesel fuel and biodiesel prepared via transesterification of waste cooking oil

Recent studies have found potentials in the utilization of biodiesel from renewable energy sources to tackle environmental pollution associated with the release of exhausts from fossil diesel fuel engines. However, it's imperative to investigate the corrosion rate and nature of the engine components fuelled with the biodiesel. This study examines the corrosion rate and nature of aluminum coupon (AC) in fossil diesel fuel (DF) and biodiesel produced from waste cooking oil via transesterification reaction (WCOB) using weight loss and electrochemical measurements. Taguchi Orthogonal Array was used to study the influence of temperature, immersion time, agitation and WCOD/DF volume. Weight loss method revealed highest corrosion rates to be 0.0052 mm y−1 and 0.0381 mm y−1 for AC in DF and WCOB respectively. Corrosion rate increased with increase in immersion time and temperature. A shift in the corrosion potential from -0.192 V to -0.574 V; and -0.178 V to -0.516 V was revealed by potentiodynamic polarization curve for AC in WCOB and DF respectively. Nyquist plots exhibited relatively perfect semicircles of different diameters and similar shape. The developed mathematical models were effective for corrosion rate prediction. Minimum corrosion rates of 1.222 × 10−3 mm y−1 and 1.822 × 10−3 mm y−1 for AC in DF and WCOB are respectively feasible at optimum point. Presence of carbon and oxygen on AC surface; pits formation; and loss of Al ion into WCOB and DF after corrosion were noticed. In conclusion, the corrosion rate of AC in WCOB was higher than the DF counterpart.

Case-Time Series Study on the Short-term Impact of Meteorological Factors on West Nile Virus Incidence in Italy at the Local Administrative Unit Level, 2012 to 2021.

IntroductionWest Nile Virus (WNV) is a significant public health concern in southern Europe, with meteorological, climatic, and environmental factors playing a critical role in its transmission dynamics. This study aims to assess the short-term effects of meteorological variables on the incidence of WNV in five Italian regions in Northern Italy from 2012 to 2021. MethodsLinking epidemiological data from the national surveillance system and local meteorological data, we conducted a Case-Time Series analysis to examine the association between WNV incident cases and temperature, humidity, and precipitation recorded up to ten weeks before case occurrence at the local administrative unit level. We employed conditional quasi-Poisson regression and distributed lag non-linear models to explore delayed effects. ResultsOur study analyzed 1,110 autochthonous human cases of WNV. We found a positive association between WNV incidence and weekly mean temperature recorded between one to nine weeks before the diagnosis, with the highest effect at one week lag (IRR: 1.16; 95% CI 1.11-1.21). An increase in weekly precipitations between the sixth and ninth weeks before diagnosis was also positively associated with WNV incidence. Variations in minimum weekly humidity did not show a consistent impact. ConclusionsOur findings underscore the influence of temperature and, to a lesser extent, precipitation on WNV incidence in Northern Italy, highlighting the potential of climatic data in developing early warning systems for WNV surveillance and public health interventions.

The impact of temperature on the growth of Pseudomonas aeruginosa in mineral waters originated from different wells: A predictive approach

This study aimed to evaluate the behavior of Pseudomonas aeruginosa (PSA) in natural mineral water sourced from three different extraction wells and stored at various temperatures (10, 12, 20, 23, and 30 °C) to calculate the kinetic growth parameters of this microorganism through predictive modeling. The physicochemical characterization of waters was also evaluated at the time of collection, and included the analysis of 40 different minerals, and quality parameters such as pH, conductivity, oxidation-reduction potential (ORP), total dissolved solids (TDS), salinity (PSU), and temperature (T). PSA survived in raw mineral water incubated at 12, 20, 23, and 30 °C; however, no growth was observed at 10 °C. Growth curves started with an initial population of ~ 2.5–3 log CFU/mL, and final PSA populations ranged from 3.5 to 4.9 log CFU/mL. The maximum specific growth rate (μmax) at 30 °C varied among the wells, with Well P-07 showing the highest growth rate (0.2 h−1), followed by Well P-08 (0.195 h−1) and well P-01 (0.133 h−1). At 12 °C, well P-01 exhibited the highest growth rate (μmax = 0.22 h−1), indicating a influence of mineral composition in the growth of PSA. The lag time (λ) also varied, with minimum values of 2.4 ± 0.1 h at 30 °C and maximum values of 41.6 ± 0.2 h at 12 °C. From these primary estimated parameters, it was possible to obtain five robust secondary models to describe the influence of temperature on the maximum growth rates and lag phase of PSA in the well. The estimated PSA growth parameters at 20 and 23 °C were subjected to a hierarchical cluster analysis and correlation plots to verify the influence of the physicochemical composition of the waters on the PSA behavior at each well's specific annual average temperature. This analysis confirmed a positive relationship (p < 0.05) between the presence of minerals (Ca, Fe, Sr, Mn, Na) and ions (SO4−3, Cl−) and the PSA lag phase time. These results underscore the need for tailored water quality management strategies that consider chemical composition and temperature to address specific microbial contamination risks.