Temperature Of Mixture Research Articles

Experimental study and thermodynamic modeling of CO2+CH4 gas mixture hydrate phase equilibria for gas separation efficiency

Gas separation is a critical application of gas hydrates, and accurately predicting separation performance is crucial. In this study, we used thermodynamic calculations to predict the equilibrium phase of gas hydrates for various mole fractions of CO2 + CH4 gas mixtures. We also determined the mole fraction of each gas component trapped within the hydrate clathrate. To predict the equilibrium points, we used the Soave–Redlich–Kwong（(SRK) equation of state for the gas phase, the nonrandom two-liquid (NRTL)model for the liquid phase, and the Chen–Guo model for the hydrate phase. We modified the hydrate fugacity formula and introduced a new function to improve the accuracy of the Chen–Guo model. By incorporating experimental equilibrium results from our study and another study, we developed a correlation based on gas mixture composition and temperature, resulting in highly accurate predictions. The use of this new correlation for hydrate fugacity calculation significantly improved precision, as evidenced by an average absolute deviation percent of calculated pressures (AADP) of 1.34% for pure CO2 and 1.25% for CH4. When considering the 27 data points of different CO2 + CH4 mixtures, the AADP% was 1.98%.To implement the model to predict equilibrium phases, we used the Chen–Guo framework to determine the mole fraction of each gas component in the hydrate mixture. Interestingly, we discovered a linear correlation between the CO2 mole fraction in the hydrate and equilibrium pressure, with a slope of approximately 0.001 and a y-intercept of less than one, for all gas compositions. Therefore, we can conclude that low thermodynamic conditions (temperature and pressure) result in a high CO2 mole fraction in the hydrate phase and great separation efficiency.

CFD-aided enhancement of propylene oxide decomposition in a tubular reactor with a corrugated cooling jacket

_This research delves into the decomposition kinetics of propylene oxide within a novel reactor design characterized by a corrugated inner wall for enhanced cooling. By applying Computational Fluid Dynamics (CFD), this study aims to optimize the reactor's heat transfer capabilities to achieve precise control over the exothermic decomposition process. This approach addresses a previously unexplored area in CFD application, proposing a model that fine-tunes the decomposition efficiency of propylene oxide by considering the interplay of key parameters such as inlet mixture temperature, activation energy, flow rate, and the resulting thermal profile. The primary goal is to advance the development of more efficient and environmentally friendly chemical processing techniques in the propylene oxide industry. The study highlights the critical relationship between activation energy (74–76 kJ/mol), process temperature (29–37 °C), and cooling efficiency in optimizing the decomposition process. Significant findings indicate that higher inlet temperatures (37 °C) and lower activation energies (74 kJ/mol) lead to superior conversion rates. The study presents a clear correlation between temperature elevation, reduced activation energy, and enhanced conversion rates, demonstrating that optimizing these parameters can lead to significantly improved conversion efficiencies, potentially approaching 100 % under ideal conditions.

Using the group contribution method to predict the flash temperature of biodiesel and ethanol mixtures

This article presents a novel approach to predict the flash temperature of biodiesel and ethanol mixtures using the Group Contribution Method (GCM). Expanding on the pioneering work by Liaw et al. (2003), our method employs GCM to calculate the activity coefficients of biodiesel and ethanol components in the mixture. Estimating these coefficients, crucial for accurate flash temperature prediction, involves a comprehensive analysis of composition, functional groups, and vapor-liquid equilibrium (VLE) data. For this purpose, the composition of the mixture components in biodiesel, the functional groups within each biodiesel component, the composition ratios of biodiesel and ethanol in the mixture, and the functional groups present in ethanol are considered. Given that the use of UNIQUAC and NRTL models requires estimating adjustable parameters, VLE data for ethanol and biodiesel mixtures are employed to calculate the activity coefficients. This approach not only aids in estimating these coefficients but also facilitates determining the values associated with each functional group. Flash temperature predictions for biodiesel and ethanol mixtures obtained through various models, including the ideal solution, UNIQUAC, NRTL, and our proposed GCM, are rigorously assessed. The results indicate that the GCM method outperforms the alternatives, exhibiting the lowest error with a deviation of just 1.72 K compared to deviations of 1.77 K, 1.75 K, and 1.73 K for the ideal solution, UNIQUAC, and NRTL models, respectively. This research offers a promising approach for flash point estimation in complex systems, such as biodiesel-ethanol blends, contributing to the ongoing exploration in this field.

Study on temperature regulation capability of asphalt mixture modified by dual phase change material used in ultra-thin overlay

ABSTRACT A dual-phase change material (DPCM) containing polyethylene glycol (PEG) 400/expanded graphite (EG) and PEG1500/EG with both high and low-temperature regulation capacities was prepared. It was added as an additive to the NovaChip-Type C asphalt mixtures. Laboratory and field temperature regulation tests were designed. The images taken by SEM showed that PEG was fully adsorbed by EG and the structure of DPCM was stable. The test results showed the DPCM has good durability in the cyclic phase change process. The modified asphalt binders with different DPCM content showed different heat storage capacity. The results of temperature regulation tests showed that the addition of DPCM effectively reduced the temperature change rate of asphalt mixtures. With 1.88% DPCM, the extremum of high temperature of asphalt mixtures reduced by 2.3°C while the extremum of low temperature increased by 2.0°C. In terms of road performance, the cracking resistance at low temperature of asphalt mixtures gradually improved with the increase of DPCM content. Meanwhile, the rutting resistance at high temperature and water damage resistance still met the requirements of the specification. The DPCM had a good effect on restraining the occurrence of road diseases caused by temperature and prolonging the service life of the road.

Comparative Investigation of Large-Scale Cells of Supercapacitors Using Low-Temperature Electrolytes

The implementation of the concept of sustainable development for humanity, the advancement of alternative energy, hybrid and electric transport, and backup power supply systems, necessitate the creation of efficient energy storage devices. Such systems include lithium-ion, nickel-metal hydride, and redox flow batteries, where Faraday processes play a crucial role in energy storage mechanisms. One notable advantage of double-layer supercapacitors (SCs) as energy storage devices is the absence of Faraday processes during charge and discharge [1,2]. Moreover, the absence of Faraday processes, the rate of which sharply decreases with decreasing temperature, makes SC cells practically the only devices where power and energy features can potentially be maintained at a sufficient level at extremely low temperatures, down to minus 70-80°C [3]. The demand for developing energy storage systems capable of operating at extreme temperatures without extensive thermal control, such as space avionics systems, electric aircraft, uncrewed aerial vehicles, and electric and hybrid electric vehicles, is growing.Various methods have been adopted today to improve the performance of supercapacitors at low temperatures [4,5]. The central aspect in this direction is electrolytes, which have the most critical impact on the supercapacitor performance at these temperatures. While many investigations have been conducted on laboratory cells, a comparative analysis of the electrochemical characteristics of cells based on the developed electrolytes (non-aqueous electrolytes) was carried out to understand the correlation between laboratory and large-scale manufactured SC cells.The electrolyte mixture was prepared using organic substances: acetonitrile (AN), ethyl acetate (EA), toluene (TL), diethyl ether (DE), and vinylene carbonate (VC). A 1.2 M solution of salt TEMA TFB was used to prepare the electrolyte. Test electrolyte mixtures were prepared by adding the test additive in the amount of 5, 10, 15, and 20 vol% for DE and TL and 0.1, 1, 3, and 5 vol% for VC to the AN: EA (3:1 by volume %) mixture. These co-solvents were chosen due to their low melting point, relatively low viscosity, and moderate dielectric constant values.A comprehensive investigation of the physical-chemical and electrochemical properties demonstrates that additives to the electrolyte mixture can extend the lower boundary of the operating temperature range down to −68°C, providing good electrochemical characteristics of the cells: capacitance and stability during long-term cycling [6].To understand the behavior of developed electrolytes in large-scale SC cells, manufactured large-scale SC cells (LSC) with a standard initial capacitance of 1500F were used. Figure 1a shows the capacitance change of large-scale SC cells based on electrolyte mixture AN: EA (3:1), AN: EA (3:1) +3%VC, AN: EA (3:1) +10%DE, and AN: EA (3:1) +10%TL at +25°C. It is evident that the capacitance of LSC-based SC is nearly maintained for more than 1000 charge-discharge cycles at a temperature of +25°C, demonstrating better performance than laboratory cells. Equivalent measurements were also carried out on the self-discharge of LSC-based SC cells (Fig. 1d), showing only a slight voltage drop for just over 2 days.This behaviour indicates high resistance to various electrochemical processes, such as electrochemical decomposition of the activated electrode material and electrolyte compound,corrosion of the current-collector material,undesirable Faraday redox processes. Notably, the leakage current for large-scale cells is lower than for small (laboratory) cells, enhancing the capacitance retention ability for large-scale cells. Figure 1. Cycle-life stability (a, b, c) and self-discharge behavior (d) of the LSC cells based on electrolyte mixtures at temperatures of 25 °C (a, d), -60 (b) and -65 (c).For all samples, an increase in capacitance is observed as the number of charge-discharge cycles increases (Fig.1). This is likely due to the high current value (50A) used for large-scale cells, causing Joule heating in the cell structures, and increasing the temperature of the electrolyte mixture by several degrees.Tests of the developed electrolytes as part of laboratory SC cells and large-scale industrially produced SC cells confirmed their high resource stability during 10,000 cycles of continuous charge-discharge at a current density of 1.5 A/g, including at a temperature corresponding to the upper limit of the operating temperature range. Additionally, the resistance of SCs with these electrolytes to self-discharge was demonstrated, showcasing the possibility of a "cold start" of SC elements at a temperature of –60 °C.

High Density Two-Component Glasses of Organic Semiconductors Prepared by Physical Vapor Deposition.

Physical vapor deposition (PVD) is widely utilized for the production of organic semiconductor devices due to its ability to form thin layers with exceptional properties. Although the layers in the device usually consist of two or more components, there is limited understanding about the fundamental characteristics of such multicomponent vapor-deposited glasses. Here, spectroscopic ellipsometry was employed to characterize the densities, thermal stabilities, and optical properties of covapor deposited NPD and TPD glasses across the entire range of composition. We find that codeposited NPD and TPD form high density glasses with enhanced thermal stability. The dependences of density and stability upon substrate temperature are correlated, and the birefringence of the codeposited glasses is determined by the reduced substrate temperature of mixtures. Additionally, we observe that the transformation of a highly stable and dense two-component glass into its supercooled liquid initiates from the free surface and propagates into the bulk at a constant velocity, like single component PVD glasses. All of these features are consistent with the surface equilibration mechanism.

Spray-Flame Synthesis of NASICON-Type Rhombohedral (α) Li1+xYxZr2-x(PO4)3 [x = 0-0.2] Solid Electrolytes.

Since solid electrolytes have a broad electrochemical stability window, are exceptionally electrochemically stable against Li metal, and function as a physical separator to prevent dendrite growth, they are at the forefront of alternate possibilities, further increasing the stability and energy density of Li-ion batteries. NASICON-type electrolytes are a promising candidate due to their negligible moisture sensitivity, which results in outstanding stability and a lower probability of Li2CO3 passivity under the ambient atmosphere. However, one of the most promising representatives, Li1+xYxZr2-x(PO4)3 (LYZP), has multiple stable phases with significant variation in their corresponding Li-ion conductivity. In this paper, we have successfully synthesized the highly ionically conductive rhombohedral phase of LYZP via spray-flame synthesis. Two different solvent mixtures (e.g., 2-ethyl hexanoic acid/ethanol, propanol/propanoic acid) were chosen to explore the effect of precursor composition and combustion enthalpy on the phase composition of the nanoparticle. The as-synthesized nanoparticles from spray-flame synthesis consisted of the crystalline tetragonal zirconia (t-ZrO2) phase, while lithium, yttrium, and phosphate were present on the nanoparticles' surface as amorphous phases. However, a short annealing step (1 h) was sufficient to obtain the NASICON phase. Moreover, we have shown the gradual phase conversion from orthorhombic β phase to rhombohedral α phase as the annealing temperature increased from 700 °C to 1300 °C (complete removal of β phase). In this context, Y3+ doping was also crucial, along with the appropriate solvent mixture and annealing temperature, for obtaining the much-desired rhombohedral α phase. Further, 0.2 at% Y3+ doping was added to the solvent mixture of 2-ethyl hexanoic acid/ethanol, and annealing at 1300 °C for 1 h resulted in a high ionic conductivity of 1.14∙10-5 S cm-1.

Investigations of Combustion Characteristics of N-Dodecane/Air Mixtures at High Temperatures Through Laminar Burning Velocity Measurements

ABSTRACT In this work, combustion characteristics of premixed n-dodecane/air mixtures are investigated at elevated mixture temperatures through laminar burning velocity measurements at atmospheric pressure and elevated temperatures using an externally heated diverging channel method. The experiments were conducted up to high-temperature conditions of 610 K at varying equivalence ratios (ϕ = 0.7–1.3) to mimic the conditions of practical application devices. With an increase in the mixture temperature, the laminar burning velocity increases because of the rise in reactant enthalpy. The peak laminar burning velocity is observed at ϕ = 1.1 for all the mixture temperatures, except at 600 K, where the maximum laminar burning velocity is observed for stoichiometric conditions. The minimum temperature exponent exists for a slightly rich mixture condition (ϕ = 1.1). Out of all mechanisms, the laminar burning velocity predictions using the Lawrence Livermore National Laboratory model are consistent with the present data at all mixture temperatures. Normalized sensitivity analysis is analyzed using the Lawrence Livermore National Laboratory mechanism to understand the key reactions affecting the laminar burning velocity of the n-dodecane/air mixture. The chain branching reaction R16: H + O2 <=> O + OH has a major influence on the enhancement of the laminar burning velocity. Reaction pathway analysis is carried out at stoichiometric conditions for mixture temperatures of 400 K and 600 K, where it is observed that the elemental flux of the reaction, converting CO to CO2, gets reduced by 42.91% at the high-temperature condition.

Modelling of JP-8 distributed combustion using a HyChem mechanism under gas turbine conditions

The critical advantages of liquid fuels in aviation over alternative energy carriers imply their dominance in the upcoming decades. The Mixture Temperature Controlled (MTC) combustion concept allows spatially homogeneous, efficient burning (distributed combustion) with low pollutant emission. MTC combustion of jet fuel JP-8 was investigated in an atmospheric burner, and the measured pollutant concentrations in the flue gas were reproduced using the Hybrid Chemistry (HyChem) approach employing Perfectly Stirred Reactor simulations. Using this robust approach comes with losing spatiotemporal characteristics if the mixture homogeneity assumption is globally valid. The effect of residence time and pressure under typical gas turbine operating conditions was investigated. Stable combustion was present above 3 ms residence time at pressures up the 60 bar, which was the upper limit of the investigated regime, while the lower residence time limit of stable combustion was 0.3 ms. The residence time interval of stable operation could be extended by applying flue gas recirculation. NO emission can be reduced by increasing the operating pressure, while the N2O production is dominant only up to 20 bar and in the 10–100 ms residence time range. CO emission vanishes above 10 ms residence time. Ultra-low emission operation requires >20 bar pressure and 10 ms residence time with distributed combustion, requiring larger combustion chambers for future jet engines.

Experimental and Theoretical Investigation of Thermal Parameters Influencing the Freezing Process of Ice Cream

Freezing time stands out as the most critical parameter in ice cream production, significantly influencing the final product’s quality and production efficiency. Therefore, it is essential to accurately estimate the freezing time based on ice cream recipes. This research paper focuses on determining the thermal properties of ice cream samples by leveraging insights from previous studies. Moreover, a new specific heat correlation is proposed to account for the latent heat effect of water during the freezing process. The results demonstrated that the new specific heat correlation aligns well with established formulas from previous research as well as experimental results with maximum 2.5% deviation. To validate the accuracy of the proposed numerical model, experimental studies were compared with numerical results for the first time in the context of ice cream freezing inside a mold. Additionally, a parametric analysis was conducted using numerical modelling to discern the relative importance of various production process parameters. Notably, the glycol–water mixture temperature emerged as the most influential parameter affecting freezing time, while the amount of air inside the ice cream was identified as the least significant factor.

Analysis of the hydrogen safety of the NPP with a VVER-1200/V-491 reactor in a severe beyond design based accident

The results of a computational analysis of possible modes of combustion of a hydrogen-air mixture in containment during the evolution of a severe beyond design basis accident (BDBA) with the COCOSYS code are presented. The containment of the NPP with a VVER-1200/V-491 reactor was selected as the object of study. BDBA with loss of coolant occurs due to a break of the injection pipeline of the pressurizer system (LOCA DN179) and the simultaneous failure of all active channels of the emergency core cooling system (ECCS). The calculated parameters of the thermodynamic state (pressure and temperature) of the gas mixture are given, and the values of the concentration distribution of hydrogen inside the containment are presented. After calculating the hydrogen distribution and mixing in all compartments of the containment, an evaluation was made of the flammability of the mixture and the potential for self-ignition in the containment by using a three-component Shapiro-Moffette diagram. It was concluded that in BDBA (LOCA DN179 with failure of active ECCS) detonation of the hydrogen-containing mixture is excluded, and deflagration is possible only in the emergency compartment of steam generators with a pipeline break. Thus, the hydrogen risk mitigation has been achieved in accordance with the standards established by the Belarusian regulator, provided that the localization safety systems are operational in the event of hydrogen deflagration. And the efficiency of the hydrogen removal system from the containment using catalytic recombination is considered sufficient for the considered BDBA.

Improving the technology for Inflow Profile Evaluation in horizontal Wells by temperature changes Due to calorimetric Mixing

The paper is devoted to the problem of increasing the effectiveness of temperature logging quantitative interpretation for the inflow profile evaluation in horizontal production wells draining heterogeneous reservoirs with low permeability. Such wells are characterized by an extremely uneven distribution of inflow along the length of the wellbore. One of the ways of quantitative interpretation of temperature logging is based on the effect of calorimetric mixing. It’s widely used to quantify the share of local producing intervals in the total flow rate.The low accuracy of interpretation is associated with the lack of reliable information about the temperature of the fluid flowing into the wellbore. The authors propose an estimate of this parameter based on the similarity of the behavior of the temperature field vs time in the near-wellbore zone of a reservoir during periods of stable production and the periods of the well shut-in. This relationship is confirmed by the results of modeling the temperature field of the “well – reservoir” system, taking into account changes in a wide range of reservoir permeability and thermal properties of the reservoir, the geometry of hydraulic fractures in the reservoir, the flowing fluids, as well as the parameters of the well production targets. The logging technology recommended by the authors involves the registration of several temperature profiles along the length of the wellbore at the beginning of the well production with the maximum rate and drawdown and during the well shut-in. Their integrated analysis based on the behavior of the temperature field features in time identified on the basis of modeling makes it possible to evaluate with a high degree of certainty the dynamics of the temperature of the gas-liquid mixture coming from reservoirs to the wellbore during production periods. This provides the required accuracy in the quantitative assessment of the inflow profile from mixing anomalies.The proposed approaches to the interpretation of thermograms are applicable in the analysis of the results of non-stationary temperature logging results in horizontal and vertical wells during the production from heterogeneous reservoirs both through perforation and multi-stage hydraulic fracturing.

Performance of a high-temperature transcritical pumped thermal energy storage system based on CO2 binary mixtures

Pumped thermal energy storage is a novel energy storage technology with features of high efficiency, geographical independence and suitable for bulk capacity energy storage. As a subset of pump thermal energy storage system, the transcritical CO2 arrangements have received widespread attention due to their excellent thermodynamic performance. However, the high cost and low efficiency of heat exchange progress caused by CO2 phase transition hinder the transformation of this system from scientific theory to practical application. CO2 binary mixtures is innovatively employed as working fluid in proposed system. The temperature of mixture is variable rather than remaining constant during the evaporation and condensation progresses. R134a, R290, R600 and R601 are selected respectively to mix with CO2 to form the new working fluids. Advanced thermodynamic and economic models are established to investigate the performance of novel systems. Results indicate that the system driven by CO2/R134a with a refrigerant mass fraction of 0.15 exhibits the optimal overall performance. At the optimal point of the 10 MW/8h system, the round trip efficiency and levelized cost of storage are 66.18 % and 0.146 $/kWh, respectively. Moreover, the investigation of system performance with various energy storage capacities is put forward. It is shown that when the energy system capacity reaches 300 MW, the levelized cost of storage can be reduced to 0.122 $/kWh. To adapt to different peak and valley periods in different regions, systems with different charge and discharge times are investigated and it is found that the charge duration should better be equal to the discharge duration.

Study on the unheated gathering boundaries of crude oil during high water content period in cold region

The energy consumption of oil gathering and transportation can be effectively reduced by using an unheated gathering process in oilfields with high water content. However, the phenomenon of “condensate sticking to the wall” may arise due to low temperatures in the cold region, which affects the safe production of this process. In this study, the safe production temperature limit of high water content crude oil in a cold climate without heating is determined by using a combination of a cold finger experiment and a field test. Research using cold finger devices indicates that crude oil’s viscous wall temperature typically below the pour point and diminishes as water content and shear stress rise. Through field tests with gradually decreasing oil–water mixture temperatures, the relationship between the oil–water mixture temperature and pipeline pressure drop is established. The temperature at the pressure drop surge point is then chosen as the limit for unheated gathering and transportation. A model for calculating the viscous wall temperature considering the flow state is established, its average calculation error is 1.44%. This study can provide important guidance for the feasibility judgment of the unheated gathering and transportation process and its safe operation in oil fields in cold regions.

Determining phase-transition temperatures of molten salt mixtures through microsecond-scale staircase voltammetry

Determining the phase-transition temperature is crucial in the design of molten salt reactors, as operational temperatures need to be established considering the safety margins related to the thermodynamic stability of the molten salt system. This study introduces a novel approach to determine the phase-transition temperature based on rapid electrical conductivity measurements using a microsecond-scale staircase voltammetry technique. The phase-transition temperature is determined near distinct points where the electrical conductivity abruptly changes, indicating phase transitions. The phase-transition temperatures of three LiCl–KCl molten salt systems, determined using the proposed approach based on electrical conductivity measurements, are with relative errors less than 3% compared with reported phase transition data based on conventional thermal analysis techniques.

Microwave De-Icing Efficiency Improvement of Asphalt Mixture with Structural Layer Optimization and Heat-Resistance Design.

The application of microwave de-icing technology in road engineering is constrained by its low energy utilization rate, which can be attributed to low heat production rates and ineffective heat dissipation to the underlying pavement. In this work, asphalt mixtures are designed as an upper layer (heating layer) and a lower layer (thermal-resistance layer). Magnetite slag was selected as a microwave-sensitive source for generating heat, and expanded perlite powder was incorporated into the lower layer as a thermal resistance material. Structural layer optimization and thermal-resistance layer design of the asphalt mixture were carried out by changing the thickness of the upper and lower layers to further improve the heat production rates. The design effectiveness is comprehensively evaluated by factors such as the changing law of the average surface temperature of mixtures, ice-melting time, and cost-effectiveness analyses. The results show that EP possesses better thermal stability, lower microwave energy conversion ability and more excellent heat-resistance potential compared with mineral powder. The heat-resistance layer with EP can prevent heat from being conducted to the lower layer and promote it to concentrate on the specimen surface, which can endow the microwave heating efficiency of specimens to be further improved by up to 26.97% and the de-icing time reduced by 10%, ascribed to the heat-resistance design. Furthermore, the collaborative design of the structural layer optimization and heat-resistance layer can increase energy utilization efficiency and save microwave-absorbing materials while ensuring excellent microwave de-icing efficiency.

Effect of electrophysical treatments on the storage life of potatoes and other vegetable crops

To prevent the progression of various infectious diseases, seed and planting material must undergo treatment with ultraviolet (UV) radiation at an intensity of 10-15 kilojoules. This necessitates studying the impact of UV radiation on products as they move in a flow along a conveyor belt. (Research purpose) The study aims to evaluate the feasibility of using ultraviolet radiation to improve the storage indicators of potato and other vegetable crops. It also assesses the technological parameters in both laboratory and production settings to ensure a reduction in contamination. (Materials and methods) To determine the optimal technological parameters of a machine for processing vegetable crops and potatoes before storage in the post-harvest processing system, an experimental installation was created and the electrophysical effects on storage quality indicators were examined. For the study, the most common vegetable crop varieties were selected, in particular, Lady Rosetta potato, Vitaminnaya-6 table carrot and Bordeaux 237 table beet. These crops are cultivated under various soil and climatic conditions across the Russian Federation. (Results and discussion) A methodology has been developed to assess the quality of seed material after the storage period, including the justification for the time interval, air mixture temperature parameters and ultraviolet radiation optical modes. The optimal parameters for processing potato tubers, carrots, and beets have been determined. The study examined the impact of ultraviolet exposure with established parameters on the disease development in carrot and beet crops, caused by the studied phytopathogenic microorganisms at temperatures of 2 and 25 degrees Celsius. (Conclusions) The indicators of the spread and development of infectious diseases in the studied vegetable crops show a decline trend when the translational speed of root crop movement is 0.7 meters per second, the interaxial distance between ultraviolet radiation sources is 0.1 meters, the distance from the sources to the roller surface of the conveyor belt is 0.05 meters, and a constant dose of ultraviolet exposure is applied.

Experimental study of nitric oxide distributions in non-premixed and premixed ammonia/hydrogen-air counterflow flames

This study reports an experimental investigation of quantitative Nitric Oxide (NO) distribution in both premixed and non-premixed NH3/H2-air flames using a counterflow burner at atmospheric pressure. One-dimensional (1D) NO laser-induced fluorescence (LIF) spectroscopy and Raman/Rayleigh spectroscopy were conducted to accurately resolve the quantitative 1D NO profile in terms of mixture fraction, temperature, and physical space. We calibrated a saturated NO-LIF model in 5 premixed lean H2/N2/NO-air flames with different seeded NO levels in a McKenna burner and validated its accuracy in three H2N2NO-air counterflow diffusion flames. The overall uncertainty of NO quantification was less than90 ppm. Our measurements were compared with simulations using different ammonia chemical kinetic models, revealing that current models have over 30% uncertainty in predicting peak NO concentrations (mole fraction) in 1D non-premixed and premixed flames and over 100% uncertainty in lower temperature regions. In premixed flames, measured NO concentrations fell within the intermediate range of current chemical kinetic models at lean and stoichiometric conditions, but were lower than the models at rich conditions. In non-premixed flames, all models overestimated the peak NO concentrations by more than 1000 ppm. It is noted that the measured peak NO concentrations increased with higher NH3/H2 ratios (from 4/6 to 8/2), strain rates (from 80 to 140 1/s), and N2 dilution ratios in a 1:1 NH3/H2 mixture (from 0 to 30%). Although most models could qualitatively predict the trends, they were inaccurate in quantifying NO. Additionally, the measured width of the NO profile in mixture fraction space expanded with increasing NH3/H2 ratio, N2 dilution ratio, and strain rate. While models could qualitatively predict this behavior, they consistently underestimated NO in the fuel-rich, lower-temperature region, resulting in a narrower NO profile width. The Manna model showed a better prediction of NO distribution in the fuel rich portion of non-premixed flames, accounting for NH3NO interactions at lower temperatures. These findings highlight the critical need to improve models to accurately predict NO concentrations in ammonia-containing flames and their behavior in fuel rich regions.

Thermal and structural evaluation of an asphalt pavement with an embedded inductive power transfer pad for stationary charging of EVs

A key strategy for increasing sustainability in transportation is to increase the use of Electric Vehicles (EVs) worldwide. Charging EVs wirelessly utilizing Inductive Power Transfer (IPT) pads eliminates most of the current limitations of EVs, such as range anxiety. In this study, the effect of an IPT pad on the temperature and strain response of an asphalt mixture was evaluated. A scaled IPT pad was placed into an experimental asphalt slab and the IPT-asphalt temperature, while energizing the IPT pad, was determined by a thermal camera, Fibre Bragg Grating (FBG) sensors, and thermistors. Moreover, a static wheel load was applied on the surface of the asphalt slab, with and without an IPT pad, and the horizontal tensile strain adjacent to the bottom of the asphalt slab was measured using an FBG sensor. ANSYS simulations were conducted and were validated using the experimental results. The results showed that embedding an energized IPT pad into the asphalt slab at 20 °C increased the asphalt’s surface temperature (approximately 32 mm offset from the pad) by 8.3 °C in the experiment. Raising the ambient temperature from 20 to 50 °C resulted in an elevation of the asphalt surface temperature from 28.3 to 56.7 °C in the experimental analysis. Placement of the IPT pad into the asphalt slab was seen to decrease the asphalt strain by 41 % in the experiment. Placing the static wheel load on the edge of the pad increases the maximum tensile strain by 16 % and moving the load 66.4 mm from the edge increases the maximum tensile strain by 54 %. Significantly, applying both the thermal load and the static wheel load increased the maximum tensile strain by 53 % compared to the asphalt slab without an IPT pad.

Sustainable use of waste glass sand and waste glass powder in alkali-activated slag foam concretes: Physico-mechanical, thermal insulation and durability characteristics

In many countries, the safe removal of the massive volume of waste glass has emerged as a major environmental priority. However, the manufacture of concrete pollutes the environment with greenhouse gasses and consumes vast amounts of natural resources. As a result, the construction industry has recently been paying more and more attention to reusing glass waste to produce environmentally friendly building materials. This work aims to manufacture environmentally friendly alkali-activated foam concrete (AAFC) by examining the combined effects of waste glass powder (GP) and waste glass sand (GS) as partial substitutes for granulated blast-furnace slag (GBFS) and river sand (RS) respectively. The present study involved the experimentation of AAFC mixtures with GP contents of 0 and 10 % as a replacement for GBFS and GS contents of 0, 25, 50 and 100 % as a replacement for RS. Eight AAFC mixtures with fixed alkaline solution-to-binder (A/B) ratio of 0.5 were fabricated and cured at 80 °C for 24 h. The effects of different GS and GP contents on the oven dry density, flowability, water absorption, porosity, sorptivity, thermal conductivity, compressive strength, flexural strength, high temperature resistance and hydrochloric acid (HCI) resistance of AAFC mixtures were evaluated. Microstructure of the mixtures was analyzed by SEM and EDS. The findings indicated that the AAFC mixture with 50 % GS exhibited the best mechanical properties with a compressive strength of 3.48 MPa, representing a 71.4 % increase over the reference mixture. The mixture with 50 %GS also exhibited the lowest sorptivity regardless of GP content. Thermal conductivity enhanced by 4.6 and 7.0 % by replacing RS with 50 % GS at 0 and 10 % GP content. Replacing RS with GS and GBFS with GP increased the high temperature and acid resistance of the AAFC mixtures and the best high temperature and acid resistance were obtained for the mixtures containing 100 %GS and 10 %GP.