Influence Of Ambient Temperature Research Articles

Thermal parameter inversion of low-heat cement concrete for Baihetan arch dam

For the first time, low-heat cement was used in the entire dam section of Baihetan Dam, but the thermal properties of low-heat cement under construction conditions have yet to be fully studied. The thermal parameter values of low-heat cement may differ significantly from the indoor test values or specification values due to factors such as ambient temperature, cooling through water, and surface insulation under actual site conditions. Therefore, in order to obtain more accurate values of the thermal parameters, the hybrid swarm intelligence algorithm and field temperature monitoring data are used to identify the concrete thermal parameters of Baihetan arch dam. To overcome the shortcomings of Particle Swarm Optimization (PSO) that is easy to fall into local optimum and Artificial Bee Colony (ABC) that has insufficient development ability, an Integrated Algorithm Based on ABC and PSO (IABAP) is established. Through eight different test functions and comparing with other different algorithms, it is verified that the IABAP algorithm has certain advantages in terms of convergence speed and accuracy. Considering the influence of ambient air temperature and multi-shift water cooling during construction, IABAP is applied to the inversion of concrete thermal parameters with the same strength, different strength and different gradation of Baihetan arch dam. The computational results show the good performance of the IABAP algorithm in engineering applications on the one hand, and the applicability and reliability of the parameter inversion on the other hand, which can meet the accuracy requirements of practical engineering. At the same time, the conjecture that the thermal parameters are consistent in adjacent dam sections was verified by bringing the thermal parameters into the adjacent dam sections for simulation calculations. Finally, the experimental values of thermal parameters of low-heat cement concrete of Baihetan Dam were compared with the inverse values to analyze the change law of thermal parameters, and it was found that the final adiabatic temperature rise of low-heat concrete was smaller than the indoor experimental values during the actual construction.

Experimental studies of a remote device for biometric identification of the pre-mastitis state of the udder of dairy cows

Analysis of development of dairy cattle breeding in the Republic of Belarus is presented. The problems of reducing milk productivity and the period of economic use of dairy cows as a result of mastitis disease are noted. The importance of timely detection of sick animals, as well as treatment of the inflammatory process of the udder in the early stages is noted. The results of theoretical and experimental studies of a mock-up sample of a biometric identification device for the pre-mastitis state of udder of dairy cows are presented. In the course of experimental studies, a significant influence of ambient temperature on the thermal imaging picture was revealed, based on which the values of the radiation coefficient for cows were determined. The final adjustment of the previously established temperature ranges was made when determining one or another form of mastitis, namely, within 32.0−36.3 ℃ – the range of normal temperatures, 36.4−37.7 ℃ – “Subclinical mastitis”, 37.8−39.0 ℃ – “Clinical mastitis”. The most significant factors and optimization parameter have been determined. The percentage of the useful area of the studied object is selected as the optimization parameter. Based on the processing of experimental data, a mathematical model is obtained, described by a regression equation in the form of a polynomial of the second degree. The rational parameters of the device for biometric identification of the pre-mastitis state of the udder of dairy cows were obtained, namely: the angle of inclination of the thermal imaging module αо – 2,7o, the focal length to the object l – 794 mm, installation height of the thermal imaging module h – 495 mm. Also, based on the conducted research, priority areas and opportunities for development of the domestic agro-industrial complex through creation of integrated systems for monitoring the physiological state of animals within the framework of development of digital automated technologies of a “smart” farm have been identified.

Electrochemical and Thermal Modeling for the Fast-Charge of Lithium-Ion Batteries with Cocurrent and Countercurrent Tab Connections and the Assessment of Li Plating

Abstract Our focus is on large-format lithium-ion batteries, used in electric vehicles today and in the foreseeable future, which are charged at high rates. In order to fully charge the battery, we employ a protocol often referred to as cc-cv (constant current followed by constant voltage). We compare and contrast results for cocurrent and countercurrent tab locations. We show how the pseudo three-dimensional (P3D) model can be used to assess temperature and current distributions and determine if Li plating is expected. We demonstrate the advantages of countercurrent tab locations to (i) obtain more uniform current and temperature distributions and (ii) lower the propensity for Li plating. Sensitivity analyses include the influence of ambient temperature and cell length. The methodology laid out in this work can facilitate rational battery-cell design and robust operation, including high-rate charging.

Electrothermal Model Based Remaining Charging Time Prediction of Lithium-Ion Batteries against Wide Temperature Range

Battery remaining charging time (RCT) prediction can facilitate charging management and alleviate mileage anxiety for electric vehicles (EVs). Also, it is of great significance to improve EV users' experience. However, the RCT for a lithium-ion battery pack in EVs changes with temperature and other battery parameters. This study proposes an electrothermal model-based method to accurately predict battery RCT. Firstly, a characteristic battery cell is adopted to represent the battery pack, thus an equivalent circuit model (ECM) of the characteristic battery cell is established to describe the electrical behaviors of a battery pack. Secondly, an equivalent thermal model (ETM) of the battery pack is developed by considering the influence of ambient temperature, thermal management, and battery connectors in the battery pack to calculate the temperature which is then fed back to the ECM to realize electrothermal coupling. Finally, the RCT prediction method is proposed based on the electrothermal model and validated in the wide temperature range from − 20 ℃ to 45 ℃. The experimental results show that the prediction error of the RCT in the whole temperature range is less than 1.5%.

Exploring the pyro-phototronic effect for giant lateral photoresponse in an ITO/CdS/Si heterojunction position-sensitive detector

The demand for a high-performance position sensitive detector (PSD), a novel type of photoelectric sensor, is increasing due to advancements in digitization and automation technology. Cadmium sulfide (CdS), a non-centrosymmetric material, holds significant potential in photoelectric devices. However, the pyroelectric effect of CdS in PSDs and its influence on lateral photoresponse are still unknown. In this work, we fabricated an ITO/CdS/Si heterojunction using chemical bath deposition (CBD) and investigated the pyro-phototronic effect under nonuniform illumination. The theory of electron-hole pairs’ generation, separation, and carrier diffusion was carefully considered to understand the underlying mechanisms. Our experimental findings revealed that the device exhibited an exceptionally high position sensitivity (PS) of 1061.3 mV/mm, surpassing the generally observed PS of 655.1 mV/mm induced by single photovoltaic effect by 160.5%. Meanwhile, the PSD demonstrated rapid response times of 0.01 and 0.04 ms, respectively. Moreover, the influence of ambient temperature and electrode distance on the pyro-phototronic effect was well analyzed. Notably, the PSD exhibited remarkable stability even at ambient temperatures up to 150 °C. Despite the considerable working distance of 11 mm, the PS of the PSD remained at 128.99 mV/mm. These findings provide valuable theoretical and experimental foundations for optimizing the design and implementation of high-performance large working distance PSDs.

Experimental analysis of the influence of ambient temperature for a Loop Heat Pipe based Battery Thermal Management System

Experimental analysis of the influence of ambient temperature for a Loop Heat Pipe based Battery Thermal Management System

Temperature influence on the natural and forced vibrations of laminate plates with fractional Zener viscoelastic layers

The paper is devoted to the analysis of the influence of ambient temperature on the linear free and non-linear harmonic vibrations of laminate plates with viscoelastic layers. The Zener fractional material model is adopted. The plate kinematics is described using the refined zig-zag theory. The formulation of vibrations of the plate is based on the physical law with the separation of deviatoric and volumetric deformation. The temperature influence is included using the frequency-temperature superposition principle. The shift factor applied to modify the damping properties of the viscoelastic material is computed using the Willams-Landel-Ferry formula.The paper contains the results of several analyses of laminate plates with various viscoelastic materials for which the material data were available in the literature. In particular, the analyses focus on determination of the properties characteristic for the plates with Zener fractional model under the influence of the ambient temperature.

TEMPERATURE ERROR OF THE MEANS OF MEASURING THE GEOMETRIC CHARACTERISTICS OF BORES OF FIREARMS: MATHEMATICAL MODEL AND QUANTITATIVE EVALUATION

The work is devoted to the construction of mathematical models and quantitative assessment of the components of the temperature error of a laser triangulation sensor for measuring the geometric characteristics of bores of firearms.
 The existence of problematic issues in the field of evaluating the metrological characteristics of laser triangulation means for technical diagnostics of firearms barrel channels is highlighted. An analysis of publications
 on the evaluation of the error of a laser triangulation sensor caused by the influence of ambient temperature is carried out, and known approaches to their mathematical modeling are considered. The need to develop mathematical models of the components of the temperature error of a laser triangulation sensor and to quantify this error is substantiated.
 The parameters of the optical scheme of the laser triangulation sensor, whose deviation from their nominal (calculated) values will affect the conversion function, are determined. It is shown that the presence of a temperature error during the processing of measurement information will be perceived as an apparent change in the measured value with a constant input signal.
 On the basis of algebraic transformations of expressions reflecting the relationship between the output value of a laser triangulation sensor and deviations of the optical circuit parameters from their nominal values, mathematical models of the temperature error components are obtained and presented in the form of error component limits at the input of the measuring instrument. The expressions for determining the confidence limits of the total temperature error, taking into account the correlation between its components, are substantiated.
 A quantitative assessment of the temperature error for the characteristic combinations of weapon parameters (for four ranges of barrel calibers) in the range of ambient temperature variations inherent in the region where measurements are made is carried out. The results of the quantitative evaluation are presented in the form of graphs of the dependence of the limits of relative and absolute temperature errors on temperature and on the increase in the bore radius in the measurement range. The data obtained were analyzed, the peculiarities of the dependencies were determined, and conclusions were drawn about the compliance of the temperature error characteristics of the measuring instrument with the requirements for its accuracy.

Experimental Study of the Mechanical Properties of Full-Scale Rubber Bearings at 23 °C, 0 °C, and -20 °C.

In this study, the effects of ambient temperature on the horizontal mechanical performance of isolated rubber bearings were investigated using high-speed reciprocating loading methods. A comprehensive series of 54 experimental trials are performed on the full-scale (900 mm-diameter) isolation rubber bearings, encompassing a range of temperatures (-20 °C, 0 °C, and 23 °C), shear pressures (50%, 100%, and 250%), and frequencies (0.20 Hz, 0.25 Hz, and 0.30 Hz). Because the compression-shear tests were conducted at high velocities and pressures (specifically, vertical compressive stress of 15 MPa), the equipment used in these tests was capable of generating substantial inertial and frictional forces. Appropriate correction methodologies for the precise determination of mechanical performance metrics for bearings are presented. Then, a comprehensive investigation of the effects of various loading conditions on the characteristic strength, post-yield stiffness, horizontal equivalent stiffness, and equivalent damping ratio of LRB900 (lead-core rubber bearings 900 mm-diameter) and LNR900 (linear natural rubber bearings 900 mm-diameter) is conducted. The empirical results show a discernible relationship between these characteristics and ambient temperature as the number of loading cycles increases, except for the equivalent damping ratio. Finally, empirical fitting formulations incorporating the influence of ambient temperature are presented for each performance indicator. These formulas are intended to assist designers in performing seismic design analyses by allowing them to take into consideration the effects of ambient temperature comprehensively.

Experimental and numerical investigation of thermal environment of the child trapped in a parked vehicle

Pediatric vehicular hyperthermia (PVH) has aroused wide public concern recently. High temperatures in closed vehicles with full sun exposure and no ventilation in summer seriously endanger children's lives. Aiming at this practical problem, this study first took the temperature of child’s core body as a standard, and divided the hyperthermia into three stages: un-compensable heating (Tc > 37ºC), heat stroke (Tc > 40ºC) and critical thermal maximum (Tc > 42ºC). On this basis, two weeks of outdoor parking experiments during 10:00–18:00, using an equivalent size dummy were conducted to explore the influence of ambient temperature and solar irradiation on cabin temperature, humidity, and child’s core body temperature. According to the experimental results, at an ambient temperature of 32.4ºC, the child in the cabin developed un-compensable heating within 72 min, suffered heat stroke within 129 min, and reached the critical thermal maximum within 151 min. Considering the limitations of the experiment, a numerical study was conducted to analyze the effects of ambient temperature, solar irradiation, and window radiation characteristics on cabin temperature and flow fields comprehensively. Simulation results were in good agreement with the experiments: even at low ambient temperature Ta = 23ºC or weak solar irradiation (ts = 18:00) condition, the temperature in a closed compartment could reach the "hazardous" level. This study can provide guidance for public to increase security and prevention awareness, and promote the development of relevant policies and technologies.

A new experimental method for studying the single droplet breakup mode of diesel-water composite droplet fuel

Good atomization of the liquid phase fuel is a prerequisite for efficient combustion and micro-explosion can significantly increase the atomization. In order to study the influence of water content and ambient temperature on the breakup mode and combustion behavior of diesel-water composite droplet, a novel experimental method was proposed. Specifically, the required volume of water was placed at the end of the probe, and diesel was then dropped onto the outer surface of the water by free diffusion to form water-in-oil composite droplet. The experimental results indicated that compared with the combustion of pure diesel, the diesel-water composite droplet additionally experienced a fluctuating combustion stage, in which micro-explosion and puffing occurred. Water content and ambient temperature have dual effects on the breakup mode and combustion characteristics of composite droplet. When the water content exceeded 20%, the breakup mode of the droplet was converted from micro-explosion to puffing, which reduced the atomization performance of the fuel. The ignition time of the composite droplet was 50–60% lower than that of pure diesel, and the burnout time decreased by about 35%. The breakup mode of the droplet and the critical size results indicate that 10%water/90%diesel at 973 K is most conducive to combustion.

Genetic basis of variation in thermal developmental plasticity for Drosophila melanogaster body pigmentation.

Seasonal differences in insect pigmentation are attributed to the influence of ambient temperature on pigmentation development. This thermal plasticity is adaptive and heritable, and thereby capable of evolving. However, the specific genes contributing to the variation in plasticity that can drive its evolution remain largely unknown. To address this, we analysed pigmentation and pigmentation plasticity in Drosophila melanogaster. We measured two components of pigmentation in the thorax and abdomen: overall darkness and the proportion of length covered by darker pattern elements (a trident in the thorax and bands in the abdomen) in females from two developmental temperatures (17 or 28°C) and 191 genotypes. Using a GWAS approach to identify the genetic basis of variation in pigmentation and its response to temperature, we identified numerous dispersed QTLs, including some mapping to melanogenesis genes (yellow, ebony, and tan). Remarkably, we observed limited overlap between QTLs for variation within specific temperatures and those influencing thermal plasticity, as well as minimal overlap between plasticity QTLs across pigmentation components and across body parts. For most traits, consistent with selection favouring the retention of plasticity, we found that lower plasticity alleles were often at lower frequencies. The functional analysis of selected candidate QTLs and pigmentation genes largely confirmed their contributions to variation in pigmentation and/or pigmentation plasticity. Overall, our study reveals the existence and underlying basis of extensive and trait-specific genetic variation for pigmentation and pigmentation plasticity, offering a rich reservoir of raw material for natural selection to shape the evolution of these traits independently.

Experimental study on axial compression properties of concrete filled steel tubular stub columns in varying ambient temperature

To better understand the mechanical property issues of in-service concrete-filled steel tube (CFST) bridges susceptible to natural environmental temperatures, 13 CFST stub columns were assessed under axial compression with different ambient temperatures and steel ratios, with the strength of the core concrete as the main parameters. The influence of ambient temperature on the peak strain and joint elastic modulus of the CFST stubs was investigated. The influence mechanism of steel content and core concrete strength on the residual toughness of the CFST at different ambient temperatures was revealed. In this study, we proposed a modified constitutive equation for CFST, taking into account the ambient temperature. We demonstrated that the peak strain, residual toughness ratio, and elastic modulus of the CFST stubs significantly decreased when the temperature decreased. The calculated values of the modified constitutive equation for CFST, taking into account the ambient temperature, were in good agreement with the test results and could be used to predict the trends in stress properties of the CFST stubs at different temperatures. The results could serve as a critical reference for the design and calculation of CFST structures in very cold regions.

Will a changing climate affect hatching success in cavity-nesting birds: A case study with Eastern Bluebirds (Sialia sialis)?

A significant body of evidence indicates that climate change is influencing many aspects of avian ecology. Yet, how climate change is affecting, and is expected to influence some aspects of the breeding ecology of cavity-nesting birds remains uncertain. To explore the potential linkage between timing of first clutch, and the influence of ambient temperature on hatching success, we used Eastern Bluebird (Sialia sialis) nest records over a nine-year period from Alabama, USA. We investigated changes to annual clutch initiation dates, as well as variability in hatching success associated with ambient air temperatures during the incubation period. Using a simple linear model, we observed earlier annual egg laying dates over the nine years of this study with a difference of 24 days between earliest egg-laying date of the season. Daily temperature minima increased 2 °C across the nine-year time frame of this study. These data also indicate that Eastern Bluebird hatching success was the highest when mean ambient air temperature during incubation was between 19 °C and 24 °C (78%, as opposed to 69% and 68% above and below this temperature range, respectively). Our findings of increasing maxima, earlier maxima each year, and the lower minima of temperatures within our study area could expand the breadth of temperatures experienced by nesting Eastern Bluebirds possibly exposing them to temperatures outside of what promotes nesting success. These findings with a cavity-nesting bird highlight an optimal range of ambient temperatures associated with highest hatching success, conditions likely to be affected by climate change.

Mechanics behaviors and electrical conductivity of beryllium bronze alloy entangled metallic wire material: Experimental study and theoretical modeling

In the present work, a novel entangled metallic wire material (EMWM) with good mechanical properties and electrical conductivity was developed by using beryllium bronze alloy wire as raw material. A series of thermal-mechanical-electrical coupling tests were carried out to investigate the mechanical properties (average stiffness, loss factor) and electrical conductivity of beryllium bronze alloy entangled metallic wire material (QBe2-EMWM) and austenitic stainless steel entangled metallic wire material (304-EMWM). The effect of the density and ambient temperature on mechanical performances and resistance properties of EMWM were analyzed in detail. It is found that the mechanical properties of QBe2-EMWM are similar to those of austenitic stainless steel entangled metallic wire material (304-EMWM). The electrical resistance of EMWM decreases with the increase of density. Moreover, the electrical resistance of QBe2-EMWM is significantly lower than 304-EMWM and is only 5 % of 304-EMWM. In the aspect of theoretical modeling, based on a cube unit-cell approach, a simplified electrical resistor network was derived from modeling low-frequency current flow through the EMWM. Considering the influence of ambient temperature, the simplified resistor network model was modified by referring to the temperature term of the Johnson-Cook model, and then the conductivity model considering temperature effect for EMWM was established. The accuracy of the theoretical electrical model of EMWM was verified by comparing the calculated results with the experimental data. The results show that the proposed model can adequately predict the electrical conductivity characteristics of EMWM under different temperatures.

Design and experiment of high-field asymmetric waveform ion mobility spectrometry chip based on an integrated temperature control printed circuit board structure.

During the detection of volatile organic compounds (VOC) using high-field asymmetric waveform ion mobility spectrometry (FAIMS), the ambient temperature significantly impacts the accuracy of planar FAIMS. To mitigate the influence of ambient temperature on detection accuracy and enhance resolution, a FAIMS system based on the inner impedance characteristics of a printed circuit board (PCB) was designed for temperature control. This study, conducted under standard atmospheric pressure, aimed to assess the signal stability of a planar FAIMS instrument with and without temperature control, and the effect of temperature change on the detection ability of acetone, ethanol, and their mixture was studied using PCB self-heating. Experimental results demonstrated that the base noise in FAIMS with temperature control was 0.2pA, whereas that in FAIMS without temperature control was 1.8pA. Notably, with increasing temperature, the detection ability of FAIMS changes accordingly. The optimal relative detection ability of acetone was observed when the electrode plate was heated to 45°C under an electric field of 15 kV/cm. This study provides a novel approach to improve the resolving power of FAIMS systems and their signal-to-noise ratio. The utilization of a PCB-based temperature control proved effective in stabilizing FAIMS signal characteristics and optimizing detection capabilities, particularly for VOCs such as acetone. These findings have significant implications for improving the accuracy and resolving power of FAIMS systems in VOC detection applications.

Influence of temperature and humidity coupling on rutting deformation of asphalt pavement

Abstract In this article, ABAQUS finite-element software is used to establish an asphalt pavement structure model under high-temperature environment in summer. The changes in the temperature field and moisture concentration field of asphalt pavement are studied under the condition of 1-day continuous temperature change. The creep model is used to analyse the influence of ambient temperature and humidity on the rutting deformation of asphalt pavement. The results show that the maximum temperature of asphalt pavement can reach 60°C in the high-temperature environment in summer. The temperature accumulation effect causes the temperature of the middle and lower layers to increase by approximately 10°C, which easily induces rutting. Ambient humidity has a great influence on the change in moisture concentration in the upper layer. Considering the influence of ambient humidity in the high-temperature environment, the rut depth increases by 67%.

ПОВЫШЕНИЕ НАДЕЖНОСТИ ЭЛЕКТРОСНАБЖЕНИЯ ШКАФОВ ОПЕРАТИВНОГО ТОКА С АККУМУЛЯТОРАМИ AGM

The problem of the influence of ambient temperature on the service life of AGM technology bat-teries is considered. A brief overview of the main components of operational current cabinets is provided. An example of the operation of a battery with a violation of the temperature regime is given, as well as an analysis of the causes of battery failure. Measures have been proposed to improve the reliability of operating current cabinets

Exergy analysis of thermodynamic performance of a gas turbine unit

BACKGROUND: Gas turbine units are the most widespread type of power plants used in almost all industries. Such a wide distribution in combination with a high level of energy characteristics, high specific power and flexibility determine the relevance of research in the field of assessing their operating parameters.
 AIM: Determining the exergy characteristics (exergy efficiency and exergy dissipation factor) of a gas turbine plant and evaluation the efficiency of energy use in a gas turbine plant, as well as analysis of the influence of ambient temperature on the selected parameters.
 METHODS: The paper presents the results of an exergy analysis of the gas turbine plant as part of the Jandar Thermal Power Plant, Syria. To evaluate the described parameters, the method of exergy analysis of the thermodynamic characteristics of a gas turbine plant based on the first and second laws of thermodynamics in conjunction with the laws of conservation of mass and energy was used. An important feature of the study, which also emphasizes its novelty, is taking into account the chemical exergy of combustion gases during the exergy analysis.
 RESULTS: Based on the results of the study, it was found that the maximum exergy efficiency was 92.8% and was typical for a turbine as part of a gas turbine, while the highest exergy dissipation was observed in the process of fuel combustion in the combustion chamber and was equal to 80% (117.3 MW). The lowest exergy values corresponded to the compressor — 6.0% (9 MW). For the gas turbine unit as a whole, the total exergy dissipation was 147.3 MW and the exergy efficiency was 53.3%. In this case, the main sources of irreversibility in the gas turbine unit are the combustion chamber and combustion gases.
 CONCLUSION: Exergy analysis is a convenient method for evaluating the thermodynamic perfection of gas turbine units. As a further line of the study, it is necessary to evaluate the effects of various conditions, such as air humidity or compressor pressure ratio, on the exergy characteristics of the gas turbine fuller.

A Fitting Method to Characterize the Gaseous Venting Behavior of Lithium–Ion Batteries in a Sealed Chamber during Thermal Runaway

The venting event of thermal runaway has attracted public attention due to safety issues aroused by frequent fire accidents of new energy vehicles. However, the quantitative description of venting behavior is incomplete for tests in a sealed chamber due to the initial violent injection. In this study, nine types of batteries covering 28 cases in total were employed to investigate the influence of energy density, ambient temperature, pressure, and SOC on the venting behavior, characterized by normalized gas amount; maximum gas releasing rate; and venting durations t50, t90, t95, and t99. Then, a ‘two-point’ fitting method was proposed to modify outcomes concerning real-time gas amounts. The results show that at 100% SOC, the normalized gas amount ranges within 0.075–0.105 mol/Ah for NCM batteries and 0.025–0.035 mol/L for LFP batteries, while the maximum gas releasing rate presents a strongly positive correlation with the capacity of NCM batteries (0.04–0.31 mol/s) and a slight increase for LFP batteries (0.02–0.06 mol/s). Eventually, the three venting patterns were summarized and advanced according to the energy density and SOC of the targeted battery. This research can provide a reference for risk evaluations of the venting process and safety design for structure and pressure relief in battery systems.