Values Of Initial Temperature Research Articles

STUDY OF HEAT AND MASS TRANSFER IN WOOD-COMPOSITE MATERIALS BY MEANS OF COMPUTATIONAL FLUID DYNAMICS

Wood-composite materials (WCM), undergoes complex heat and mass transfer processes during its conditioning. Understanding these interactions is crucial for optimizing the conditioning process and ensuring high quality of the final product. This study focuses on the problem of modeling the interactions that occur during WCM conditioning, taking into account their characteristics that depend on temperature, moisture content, and density of the material. In addition, various input parameters are taken into account in the modeling process to set the optimal conditioning conditions. Despite the availability of these parameters in the literature based on the results of real experiments, consolidating this data in computer modeling is still a major problem. To resolve this issue, this study focuses on modeling the heat and mass transfer processes during WCM cooling using computational fluid dynamics (CFD) software such as SolidWorks Flow Simulation. By using the capabilities of CFD, it is relatively possible to utilize technical parameters involved in the WCM conditioning process with relative simplicity. The paper provides a detailed description of the created 3D model of the WCM-conditioning chamber and its main components. In addition, the paper describes the various input parameters used in the modeling process, including temperature, moisture content, and density of WCM. In addition, the operation of the fans was set up and the initial values of temperature, moisture content, and air velocity were set. Based on the simulation, the results obtained include the distribution of the temperature field and moisture content on the surface of the WCM at different material densities and air conditioning parameters. Additionally, the trajectory of air masses and their velocity within the 3D model was obtained. In general, the obtained results provide a better understanding of the influence of various input parameters on the process of heat and mass transfer in WCM during their cooling. Given the comprehensive analysis, this research this work can be useful for improvement of WCM production processes and quality control of final products. In particular, it emphasizes the importance of further research in this area and the need for computer modeling of such processes to further develop effective engineering solutions.

Estimation of Temperature Distribution in the Brain Using the Temperatures of Blood Inflow and Outflow for Brain Temperature Control

Brain cells can be damaged by higher temperature in the brain, and brain temperature distribution monitoring system is required from the perspective of brain preservation. Brain tissue can be further damaged by direct measurement of temperature using some sensors. Therefore, indirect methods of measuring temperature are required. In this study, we propose a method for estimating the average metabolic rate of the entire brain based on the difference between the observed and estimated blood flow temperatures that can be measured during selective brain hypothermia. Our mathematical simulator can calculate the brain temperature distribution based on the estimated average metabolic rate, taking into account other parameters like heat transfer, metabolic heat of individual tissues, heat‐washout by blood flow, and environmental temperature. The algorithm for estimating the metabolic rate of mathematical master model substituted as a human head is confirmed using the mathematical slave model on the simulator. It is possible to present the temperature distribution by estimating metabolic heat production in the brain, considering the equilibrium between heat wash‐out by the blood flow and heat transfer. In addition, an appropriate initial value of brain temperature enables the accurate temperature management enough for clinical use even in the process of temperature estimation. The development of our proposed method will make it possible to construct a non‐invasive monitoring system that presents the estimated temperature distribution in the brain instead of the conventional invasive method. The new system is expected to be utilized in a various treatments related to some brain disorders. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.

Transient temperature dynamics of reservoirs connected through an open quantum system.

The dynamics of open quantum systems connected with several reservoirs attract great attention due to their importance in quantum optics, biology, quantum thermodynamics, transport phenomena, etc. In many problems, the Born approximation is applicable, which implies that the influence of the open quantum system on the reservoirs can be neglected. However, in the case of long-time dynamics or mesoscopic reservoirs, the reverse influence can be crucial. In this paper, we investigate the transient dynamics of several bosonic reservoirs connected through an open quantum system. We use an adiabatic approach to study the temporal dynamics of temperatures of the reservoirs during relaxation to thermodynamic equilibrium. We show that there are various types of temperature dynamics that strongly depend on the values of dissipative rates and initial temperatures. We demonstrate that temperatures of the reservoirs, including the hottest and coldest ones, can exhibit nonmonotonic behavior. Moreover, there are moments of time during which the reservoir with an initially intermediate temperature becomes the hottest or coldest reservoir. The obtained results pave the way for managing energy flows in mesoscale and nanoscale systems.

Dynamics of changes in the temperature coefficient of electrical conductivity of distilled water in conductometric cells during heating and cooling

The problem of taking into account the influence of air on the properties of distilled water is considered, namely the lack of a single generally accepted method for calculating such an influence. The sensitivity of the structure of water to the influence of external factors is described and the possibility of recording and studying such factors by changes in the temperature coefficient of electrical conductivity of water is shown. The dependences of the temperature coefficient of electrical conductivity of distilled water on the rate of change in water temperature, the degree of filling of conductometric cells, as well as on the intensity of the exchange of carbon dioxide between water and air across their interface have been studied. It is noted that these metabolic processes are currently insufficiently studied. A hardware-software measuring complex has been developed and manufactured to study the temperature coefficient of electrical conductivity of water when its temperature changes within the range of 20–55 °C. The temperature coefficient of electrical conductivity of water in sealed conductometric cells was measured at different degrees of filling the cells with distilled water and the rate of heating and cooling of water. The degree of filling of the cells varied within the range of 10–100 %, the rate of change in water temperature varied within the range of 0.04–2.00 °C/min. With a constant heating and cooling time of 15 minutes in all experiments, the change in speed was achieved by changing the temperature of the heating element. The integral temperature coefficient of electrical conductivity is calculated based on the initial and final values of electrical conductivity and water temperature in each measurement cycle. The dependences of the temperature coefficient of electrical conductivity on the rate of change in water temperature at several constant degrees of cell filling were obtained. It has been shown that with a constant ratio of the volumes of water and air in the cell and an increase in the rate of heating of water, the temperature coefficient of electrical conductivity of water decreases by 19–22 %. It has been established that at a constant rate of water heating, with a decrease in the volume of water in the cell, the temperature coefficient of electrical conductivity of water decreases by 40–42 %. The results obtained can be used to quantify the dissociation coefficient of carbonic acid, the mobility of hydrogen ions, as well as the intensity of the gas exchange process under various external influences on water. Refinement of data on the electrical conductive properties of water and processes at the water/air interface is necessary for the development of models of atmospheric phenomena and climate change, as well as for the creation of sensors for weak changes in environmental parameters for the purposes of both environmental monitoring and medical diagnostics.

Learning stiff chemical kinetics using extended deep neural operators

We utilize neural operators to learn the solution propagator for challenging systems of differential equations that are representative of stiff chemical kinetics. Specifically, we apply the deep operator network (DeepONet) along with its extensions, such as the autoencoder-based DeepONet and the newly proposed Partition-of-Unity (PoU-) DeepONet to study a range of examples, including the ROBERS problem with three species, the POLLU problem with 25 species, pure kinetics of a skeletal model for CO/H2 burning of syngas, which contains 11 species and 21 reactions and finally, a temporally developing planar CO/H2 jet flame (turbulent flame) using the same syngas mechanism. We have demonstrated the advantages of the proposed approach through these numerical examples. Specifically, to train the DeepONet for the syngas model, we solve the skeletal kinetic model for different initial conditions. In the first case, we parameterize the initial conditions based on equivalence ratios and initial temperature values. In the second case, we perform a direct numerical simulation of a two-dimensional temporally developing CO/H2 jet flame with integrated chemistry modeling as a source of training data for the solution propagator. Then, we initialize the kinetic model by the thermochemical states visited by a subset of grid points at different time snapshots. Stiff chemical kinetics are computationally expensive to solve, thus, this work aims to develop a neural operator-based surrogate model to efficiently solve stiff chemical kinetics. The operator, once trained offline, can accurately integrate the thermochemical state for arbitrarily large time advancements, leading to significant computational gains compared to stiff integration schemes.

Inspecting the role of vapour loss and other model strategies in the mod-elling of a bentonite thermo-hydraulic cell

Inspecting the role of vapour loss and other model strategies in the mod-elling of a bentonite thermo-hydraulic cell

Comparison of biogas production from various blends of biomass

Because of its high organic content, biomass waste from agriculture and animals can serve as a source of raw materials for the production of biogas. The goal of this study is to determine the ideal volume and rate of biogas generation as well as the digester temperature, and material pH. This research was conducted by experimental method with 3 treatments and 3 replications, namely a mixture of cow dung with rice straw (P1), corn cobs (P2), and water hyacinth (P3). The results showed that the best biogas yield was obtained from a mixture of cow dung and rice straw (P1) with the highest initial and final temperature values of 29.8 0C and 27.3 0C, and the highest initial and final pH of 6.8 and 7.0. The highest biogas volume was 66.03 L and the highest gas production rate was 7.45 L/day.

Synthesis & spectral studies of organotin(IV) dithiocarbamates derived from 2-aminoethyl piperazine: Anticancer & anti-nematode activity

Complexes of the type L2SnR2 where R = CH3 (3), C4H9 (4), C6H5 (5), and NaL2 = sodium salt of isophthaloylbis(piperazine-4,1-diyl)bis(methylene)dicarbamodithioate have been synthesized. The compound, NaL2 have been synthesized by the reaction of 2-aminoethyl piperazine with isophthalyol dichloride followed by insertion reaction of carbon disulphide in basic media, which on successive reaction with R2SnCl2 yielded the title complexes. The precursor: L1, compound: NaL2 and its Sn complexes were characterized by spectroscopic techniques like FT-IR, 1HNMR, 13CNMR, 119SnNMR and thermal techniques like TGA/DSC. Based on FT-IR spectral studies, symmetrical bidentate coordination has been proposed for all the Sn complexes. Moreover, 13CNMR and 119SnNMR data implies that the Sn atom has been found to exhibit six-coordinate geometry in all the complexes. The TGA/DSC profile of the Sn complexes implies higher stability than L1 and NaL2. However, based on initial decomposition temperature (IDT) values the stability order of the organotin complexes was found to be 5 > 4 > 3. The room temperature conductivity values of the 1 mM solution of the precursor: L1, compound: NaL2 and its organotin complexes are found to be comparable with that of non-ionic complexes. The precursor: L1, compound: NaL2 and its three metal complexes were assayed against anti-breast cancer and anti-nematode activity. The anti-breast cancer activity of compounds 4 and 5 has been found to be most effective whilst significant anti-nematode activity has been observed for all the complexes.

THMs removal from aqueous solution using hydrochar enhanced by chitosan nanoparticles: preparation, characterization, kinetics, equilibrium studies

In this study, novel green and economical techniques were established to synthesize modified banana peel hydrochar (HBP) through hydrothermal carbonization. Chitosan nanoparticles, a green adsorbent with multiple features, were prepared, characterized, and used to enhance the performance of the hydrochar in THMs removals. The optimal method for hydrothermal carbonization was determined based on previously cited methods. The dried banana peels and HBP were characterized using Fourier transform infrared spectrometer (FTIR), pH, zero point of charge, and bulk density. The prepared chitosan nanoparticles were characterized using scanning electron microscope (SEM), transmission electron microscope (TEM), and zeta potential techniques. The average size of chitosan nanoparticles was 12.1 nm, and a 1:1 mixture of HBP and chitosan nanoparticles was used for the removal of THMs from an aqueous solution. The concentrations of THMs were measured using gas chromatography, and the effect of THMs’ initial concentrations, adsorbent doses, temperature, and pH value on the adsorption capacity was studied. The results showed that the 1:1 mixture of HBP and chitosan nanoparticles was an efficient adsorbent for removing THMs from aqueous solutions. This adsorbent was found to be effective in removing THMs from the aqueous solution, even at low temperature and pH values, with an estimated maximum sorption capacity (qm) of 588.23 g g−1, exceeding numerous other adsorbents previously studied, and the regression coefficient (R2 = 0.9959) for data fitting with the Freundlich isotherm. This research has the potential to offer a great avenue for future development and implementation in water treatment. It could lead to improved methods of treating water, which would be beneficial for both environmental protection and economic growth. The developed adsorbent had high adsorption affinity toward the THMs compounds, making the adsorption method efficient and viable technique for treating water containing such contaminants.

Co-estimation of state of charge and internal temperature of pouch lithium battery based on multi-parameter time-varying electrothermal coupling model

Accurate estimation of battery state of charge (SOC) and internal temperature can improve battery performance and safety. In this process, the accuracy of the battery's electrical model and thermal model and the applicability and robustness of the estimation algorithm are key. In this paper, a multi-parameter time-varying electrothermal coupling model for pouch batteries is established. The model takes into account the coupling relationship between the battery SOC and temperature changes, as well as the heat exchange between multiple surfaces of the battery and the external environment. And then through the improved hybrid pulse power characterization (HPPC) test to realize the identification of model parameters, and the changing external heat transfer conditions could be identified online. At last, an adaptive strong tracking square root cubature Kalman filter (AST-SRCKF) algorithm was designed to estimate SOC and internal temperature simultaneously. The results were verified by three dynamic conditions. The conclusion is that the AST-SRCKF has high robustness and can be quickly corrected when the initial values of SOC and temperature are unknown. And the estimation accuracy is higher than extended Kalman filter (EKF) and dual Kalman filter (DEKF). Furthermore, the simulation efficiency is improved by more than 6 % compared with EKF, and by more than 11 % compared with DEKF, which is more conducive to online real vehicle applications.

Prediction and validation of melt pool dimensions and geometric distortions of additively manufactured AlSi10Mg

A finite element–based thermomechanical modeling approach is developed in this study to provide a prediction of the mesoscale melt pool behavior and part-scale properties for AlSi10Mg alloy. On the mesoscale, the widely adopted Goldak heat source model is used to predict melt pool formed by laser during powder bed fusion process. This requires the determination of certain parameters as they control temperature distribution and, hence, melt pool boundaries. A systematic parametric approach is proposed to determine parameters, i.e., absorption coefficient and transient temperature evolution. The simulation results are compared in terms of morphology of melt pool with the literature results. Considering the part-scale domain, there is increasing demand for predicting geometric distortions and analyzing underlying residual stresses, which are highly influenced by the mesh size and initial temperature setup. This study aims to propose a strategy for evaluating the correlation between the mesh size and the initial temperature to provide correct residual stresses when increasing the scale of the model for efficiency. The outcomes revealed that the predicted melt pool error produced by optimal Goldak function parameters is between 5 and 12%. On the part-scale, the finite element model is less sensitive to mesh size for distortion prediction, and layer-lumping can be used to increase the speed of simulation. The effect of large time increments and layer lumping can be compensated by appropriate initial temperature value for AlSi10Mg. The study aids practitioners and researchers to establish and validate design for additive manufacturing within the scope of desired part quality metrics.

Effect of water on the mechanical and thermal properties of natural fibre reinforced hybrid composites

Research and development on natural fibre-reinforced composites (NFRCs) is constantly increasing and their use is expanding into new areas of applications. One of the main problems is the absorption of humidity due to the hydrophilic characteristic of the natural fibre, which leads to low interfacial adhesion between the fibre and the hydrophobic matrix and consequently, relatively low mechanical properties. One method to reduce the sensitivity of mechanical and thermal properties of NFRCs to water uptake is the hybridization by using synthetic fibres and/or fillers. This research investigates the effect of ageing on the mechanical and thermal properties of different natural fibre and hybrid composites. Pure jute, pure jute modified with two different types of fillers (micro glass and nano TiO2) and interlaminar hybrid jute/glass fibre-reinforced polymer composites were fabricated. Bulk specimens were used to measure the diffusion coefficient of water in the composites, and tensile and flexural specimens were used to measure the mechanical properties of the conditioned specimens. A thermogravimetric technique (TGA) analysis was used to measure and compare the degradation temperature of all composites studied as a function of ageing. Finally, a scanning electron microscopy (SEM) analysis was performed to examine the fracture surfaces of the specimens tested. It was found that the water uptake decreases by adding the synthetic fibres and the fillers to the NFRCs. The mechanical properties of the composites (the tensile and flexural strength and modulus) tend to decrease with the increase of water content, and they are partially recovered after desorption at the same temperature as the absorption. The thermal properties of natural fibre composites are affected by water absorption and by the hybridization. The hybridization of the composites increased the maximum degradation temperature when compared to the pure jute, while the addition of fillers improved the thermal properties of aged specimens (the initial degradation temperature values were higher than those for the pure jute composites).

Removal of Paracetamol by Powdered Activated Carbon Synthesized From Orange Peels

This study aims to investigate the removal of Paracetamol active ingredient from aqueous solutions with the use of powdered activated carbon obtained by ZnCl2 activation of orange peels. Equilibrium values of initial paracetamol concentration (100-500 mg L-1), pH (2-10), adsorbent dose (10-500 mg) and contact time (5-120 minutes) parameters in the removal of paracetamol from aqueous solutions are evaluated. The adsorption mechanism of paracetamol is explained with the kinetic models. The highest correlation among Langmuir, Freundlich, Temkin, and Dubinin-Radushkevichi isotherms applied to experimental data was determined as Freundlich isotherm with R2 =0.95. Pseudo-first-order and pseudo-second-order kinetic models were applied, and it was found that the latter, whose correlation coefficient is determined as R2 =0.99, is the best model to explain paracetamol adsorption. As a result of this study, it can be seen that powdered activated carbon synthesized from orange peel is an effective adsorbent in the removal of paracetamol and can be easily applied thanks to its low cost.

Effect of poly (acrylamide-co-acrylic acid salt) on anti-aging properties and adhesion between acrylonitrile butadiene rubber and polyester fabric

In this study, a multifunction polymeric adhesion promoter and anti-aging compound based on the triethanolamine salt of acrylamide acrylic acid copolymer (COS) was prepared and characterized using Fourier-transform infrared spectroscopy (FTIR). The impact of different COS contents on the tensile, adhesion, and thermal properties of NBR composite and NBR/PET sandwich was evaluated. The NBR composites containing COS displayed good retention of their mechanical properties with increasing thermal ageing time, while the composite without COS showed a decrease in its mechanical properties. The highest tensile strength (17.5 MPa with a retention value of 0.6%) after 7 days of thermal aging was recorded for NBR composite, which contains 5 phr (parts per hundred parts of rubber) of COS (COS 5), compared to NBR composite without COS (COS 0), which recorded 15.1 MPa with a retention value of -27.4%. In addition, the COS 5 composite displayed an improvement in peel strength of 16.4% compared to the COS 0. The results of the thermogarvemetric analysis (TGA) supported the anti-thermal ageing effect of COS, where the initial decomposition temperature (Ti) value increased by 11.7 and 9.3 °C, after addition of 5 and 10 phr of COS to NBR composite, respectively. In addition, the other thermogravemetric parameters investigated displayed a significant increase in their values, which confirms the improvement in thermal stability of NBR composite in the presence of COS. Also, the air permeability of the PET/NBR sandwich decreased by 80% after the addition of 7.5 phr of COS.

Adsorption characteristics of dopamine by activated carbon: Experimental and theoretical approach

In this work, we investigate the adsorption mechanism of dopamine (DP) drug using an activated carbon (AC) type through experimental and theoretical data. Experiment series were carried out at different initial values of solution pH, temperature, reaction time and initial drug concentration. The effect of protonation and deprotonation of DP molecule was also investigated. The equilibrium isotherm data were evaluated using the Dubinin-Radushkevich, Langmuir, Temkin and Freundlich models. Elovich, pseudo-first and pseudo-second order kinetic models were used to analyze kinetic data. Here we also used molecular dynamic (MD) simulation and DFT-based computational methods to reach information about the electronic properties of DP drug and its adsorption mechanism that have not been experimentally observed. Experimental results show that the Elovich kinetic model and Langmuir model best describe the adsorption phenomenon. In parallel, the experimental analysis revealed that the adsorption process is spontaneous and endothermic. Dopamine adsorption on AC occurs quickly and is pH and temperature-dependent. Frontier molecular orbital (FMO) energies for neutral, deprotonated and protonated forms of DP were determined and thoroughly explained. The basic medium significantly impacts DP drug adsorption behavior, which has the greatest adsorption energy when the pH is less than 12. It was found that DP adsorption occurs in a bidentate geometry by forming strong bonds between molecular oxygens and carbon atoms on the AC surface. Based on theoretical calculations interaction mechanisms of DP on the AC (001) surface were proposed.

DETERMINATION OF ENERGY PARAMETERS OF Ni+Al2O3 POWDER PARTICLES IN A SUPERSONIC NOZZLE DURING COLD GAS-DYNAMIC SPRAYING USING THE ANALYTICAL METHOD

Purpose. To calculate the temperature and velocity of nickel and aluminum oxide particles in the supersonic flow in the low-pressure cold gas-dynamic spraying nozzle. To investigate the effect of gas parameters at the nozzle inlet, in particular temperature and pressure, on the velocity and temperature of particles at the nozzle outlet.
 Research methods. The calculation of the temperature-velocity characteristics of the powder particles is performed after determining the parameters of the gas flow in the supersonic nozzle channel using well known gas-dynamic dependencies. The initial data for the calculation are the following: the geometry of the nozzle, the temperature and pressure of the gas (air) at the nozzle inlet. The density of the material from which particles are obtained, as well as their diameter, were taken into account in the calculation of the energy parameters. Nickel particles with a diameter of 25 µm and aluminum oxide particles with a diameter of 22 µm were used.
 Results. Based on the calculations results, graphs of changes in the velocities and temperatures of the particles of the investigated powders, as well as working gas, in the channel of the low-pressure cold gas-dynamic spraying supersonic nozzle were developed. The dependences of the temperature-velocity parameters of the particles at the nozzle exit in the range of initial values of temperature at the nozzle inlet from 300 to 600 C° and pressure from 0.6 to 1.0 MPa were also developed.
 Scientific novelty. The influence of the initial parameters of the gas at the nozzle inlet in a wide range of values on the temperature and velocity of nickel and aluminum oxide particles during the low-pressure cold gas-dynamic spraying is shown.
 Practical value. The obtained results can be used to determine rational spraying parameters in the development of technological processes of deposition of protective and restorative coatings from Ni+Al2O3 powder mixture.

Influência de fatores do pré-abate de suínos sobre o pH e temperatura inicial: estudo de caso

ABSTRACT: This study evaluated factors associated with the pre-slaughter handling of pigs in a commercial slaughterhouse located in Minas Gerais and evaluated the influence of these factors on the initial pH and temperature of the carcasses. In all, 4449 carcasses were evaluated. The factors evaluated were transport distance, transport duration, loading density, fasting duration, resting duration, average weight of the animals, average temperature in the resting area, and maximum temperature in the resting area. The effects of these factors on the initial (i.e., at 45 minutes after slaughter) temperature and pH (pH45) were measured. The pH45 values were used to determine the occurrence of PSE; the carcasses were classified as PSE when they presented a pH45 < 5.90. Results showed that animals fasted for more than 24 hours were more likely to result in PSE meat (1.41 times more likely), as did animals that were exposed to an average temperature above 24 °C (1.52 times more likely). Except for the average weight of the animals, which did not affect the initial temperature values, all other pre-slaughter factors have influenced both pH45 and the initial temperature values, and the difference of fasting duration and the temperature in the resting area increase the incidence of PSE meat.

In vitro Study of Temperature Changes on the Outer Root Surface of Extracted Human Teeth Under Different Parameters of Intracanal Cryotherapy

AbstractObjectives The aim of the present study is to investigate the temperature changes on the outer root surface of extracted human teeth during irrigation with different volumes of solutions at different temperatures.Materials and Methods Thirty premolars extracted for orthodontic or periodontal indications were used for the first experiment and 12 for the second experiment. Root canals were instrumented using WaveOne Gold. Thermosensors were attached to the apical 5 mm and to the middle 5 mm of the outer root surface. Control irrigations with 0.9% NaCl, 2.5% NaOCl, and 17% EDTA at room temperature and experimental irrigations at 2.5°C with 0.9% NaCl, 2.5°C with 2.5% NaOCl, and 2.5°C with 17% EDTA were conducted.Results During the intracanal cryotherapy, a minimum temperature more than 10°C lower than the initial temperature value was reached. There was no significant difference between the lowest temperature values reached in the irrigations carried out with the three irrigation solutions studied. These results indicate that the effect of intracanal cryotherapy can be successfully achieved using all three types of irrigation solutions, i.e., NaOCl, 0.9% NaCl, EDTA. Intracanal cryotherapy needed to last more than 2 minutes to achieve more than 10°C difference with the initial temperature.Conclusions A total of 5 mL of irrigation solution for 5 min is insufficient to achieve a cryotherapeutic effect. A temperature difference of 10°C between initial and lowest temperatures recorded was reached fastest at a volume of 20 mL.

Nitrogenous Fertilizer Levels Affect the Physicochemical Properties of Sorghum Starch.

Nitrogen is a key factor affecting sorghum growth and grain quality. This experiment was designed to investigate the physicochemical properties of sorghum starch in four sorghum varieties (Liaoza 10, Liaoza 19, Jinza 31, and Jinza 34) under four nitrogen levels: 0 kg/ha urea (N1), 300 kg/ha urea as base fertilizer (N2), 300 kg/ha urea as topdressing at the jointing stage (N3), and 450 kg/ha urea as topdressing at the jointing stage (N4). The results showed that grain size and amylose content increased with increasing nitrogen fertilizer level, peaking at N3. The peak viscosity, final viscosity, gelatinization temperature, initial temperature, final temperature, and enthalpy value increased with the nitrogenous fertilizer level, peaking at N3. The application of nitrogen fertilizer at the jointing period significantly increased the above indicators. However, excess nitrogen at the jointing period (N4) can significantly reduce the above indicators, thus changing the physicochemical properties and structure of sorghum starch. Overall, nitrogen significantly affects the structure and physicochemical properties of sorghum starch.

Comparative study on direct and indirect methods for wet desulphurisation and denitrification based on micro-nano bubbles

ABSTRACT The wet desulphurisation and denitrification technique based on micro-nano bubbles, which is available by either D-method or I-method, is a promising novel process. By employing piped water, Na2SO3 aqueous solution and HA-Na aqueous solution as the absorption liquids, a comparative study was conducted in this article on D-method and I-method to analyze their performance, advantages and disadvantages. It was accompanied by an investigation of how initial pH and initial temperature values of the absorption liquids affected the removal efficiency. The results suggested a positive correlation between NO/SO2 removal efficiencies and pH values but a little improvement in the removal efficiency under alkaline conditions. Furthermore, heating the absorption liquids inhibited the removal of NO and SO2. When manipulated in the same experimental environment, D-method and I-method did not present a significant difference in the SO2 removal efficiency, while the former was remarkably more effective than the latter in removing NO. To put together, D-method had higher removal efficiency, but required a large-scale micro-nano bubble generator to process a large quantity of flue gas as the micro-nano bubble generator was subject to a limited inlet flow rate. Consequently, an increase in investment and operating costs was incurred, while this issue could be avoided by I-method.