Optimal Temperature Conditions Research Articles

Response Surface Optimization for Antioxidant Extraction and Attributes Liking from Roasted Rice Germ Flavored Herbal Tea

The optimal process conditions when examining the antioxidant potential, total polyphenol content, and attribute liking in roasted rice germ flavored herbal tea were investigated using response surface methodology (RSM). The influence upon the extraction process of time and temperature was assessed using a full factorial design on three levels with two variables (32), involving five central point replicates. Extraction temperature (70 °C, 80 °C, and 90 °C) and extraction time (3 min, 4.5 min, and 6 min) served as independent variables, while the dependent variables were allocated to the regression equation to determine antioxidant activity (R2 = 0.941) along with total polyphenol content (R2 = 0.849), flavor liking score (R2 = 0.758), and overall liking score (R2 = 0.816). Following experimentation, it was determined that the optimal time and temperature conditions to maximize total polyphenol content, antioxidant activity, flavor, and overall liking score were in a range of 86 °C to 90 °C for 3.4 min to 5.9 min. When these conditions were imposed, the antioxidant potential, total polyphenol content, flavor, and overall liking score were >70% for DPPH scavenging activity, >75 mgGAE/g, >6.7 (like moderately), and >6.5 (like moderately), respectively.

Establishment of the upstream processing for renewable production of hydrogen using vermicomposting-tea and molasses as substrate

This study aimed to establish the optimal operational conditions for hydrogen production using vermicomposting-tea and sugarcane molasses as substrate. The experiments were carried out by triplicate in 110 ml serological bottles, a Box-Behnken design of experiments was performed in anaerobic dark conditions. The maximal hydrogen production (HP), hydrogen production rate (HPR), and hydrogen yield (HY) attained were 1021.0 mlL-1, 5.32 mlL-1h-1, and 60.3 mlLH2-1/gTCC, respectively. The statistical model showed that the optimal operational conditions for pH, molasses concentration, and temperature were 6.5; 30 % (v/v) and 25 °C. The bioreactor run showed 17.202 L of hydrogen, 0.58 Lh-1, and 77.2 mlH2gTCC-1 For HP, HPR, and HY. Chemometric analysis for the volatile fatty acids obtained at the fermentation showed that only two principal components are required to explain 90 % of the variance. The representative pathways for hydrogen production were acetic and butyric acids. This study established the operational conditions for the upstream processing amenable to pilot and industrial-scale operations. Our results add value to molasses within the circular economy for hydrogen production using a novel consortium from vermicompost.

Adsorptive behavior of L-Arginine-silica micro-particles against arsenic and fluoride in aqueous solution

The occurrence of high concentrations of arsenic and fluoride in drinking water has become a serious environmental issue. The present study reports a novel adsorbent, L-Arg functionalized silica micro-particles and its effectiveness for the simultaneous removal of arsenite, arsenate, and fluoride ions in aqueous solution. Batch adsorption experiments were performed to evaluate the efficiency of removal under the optimum condition of pH, initial concentration, contact time, adsorbent dose, and temperature. Four isothermal models were used to analyze the data: Langmuir, Freundlich, Temkin, and D-R isotherm. With a high correlation coefficient for As (III) (R2 = 0.99), As (V) (R2 = 0.99), and F- (R2 = 0.99), ions, the Langmuir isothermal model fit well. With maximum monolayer adsorption capacity of 18.76 mgg−1, 14.28 mgg−1, and 38.46 mgg−1, respectively. The kinetic analysis in all three cases followed pseudo-second-order, where observed data were in close proximity with experimental data, the thermodynamic parameters indicated that the adsorption process is spontaneous, feasible, and endothermic, where entropy increases at the solid–liquid interface. Thus L-Arg functionalized silica micro-particles could act as a promising candidate for the removal of arsenic and fluoride from potable water.

Participation of low molecular weight antioxidants selenium and caffeic acid in the regulation of respiration in Solanum Tuberosum in hypothermic conditions

To study the effect of low molecular weight antioxidants on the respiration process, the content of auxins and abscisic acid, 15-day-old potato (Solanum tuberosum) tubers grown under laboratory conditions were sprayed with 5.8 μM sodium selenite solution or 0.1 mM caffeic acid solution. Control runners were treated with water. Hypothermia (-2 °C) simulating freezing was created for 2 hours. 21-day-old runners were analyzed. Under optimal temperature conditions, the studied antioxidants stimulated the respiration process, while selenite had a greater effect. Caffeic acid increased the maintenance respiration rate. Selenite and caffeic acid increased the auxin content in the runners. Selenite reduced the amount of abscisic acid, resulting in an increase in the indoleacetic acid/abscisic acid ratio. Under hypothermic conditions, caffeic acid significantly reduced the increase in respiration, and in the option with selenite, an insignificant stabilization of this process was noted with a greater decrease in indoleacetic acid/abscisic acid ration as compared with optimal conditions.

Sitosterol-mediated Antioxidant Regulation to Enhance Heat Tolerance in Creeping Bentgrass

Heat stress symptoms in cool-season plants are characterized by loss of chlorophyll (Chl) and membrane stability, as well as oxidative damage. The objectives of this study were to determine whether foliar application of β-sitosterol, a naturally occurring plant metabolite, may promote heat tolerance by suppressing heat-induced leaf senescence as indicated by the maintenance of healthy turf quality (TQ), and Chl and membrane stability; and to determine its roles in regulating antioxidant metabolism in creeping bentgrass (Agrostis stolonifera). ‘Penncross’ plants were exposed to heat stress (35/30 °C day/night) optimal temperature conditions (nonstressed control, 22/17 °C day/night) for a duration of 28 days in environment-controlled growth chambers. Plants were foliar-treated with β-sitosterol (400 µM) or water only (untreated control) before heat stress, and at 7-day intervals through 28 days of heat stress. Plants treated with β-sitosterol had significantly greater TQ and Chl content, and significantly less electrolyte leakage (EL) than untreated controls at 21 and 28 days of heat stress. Application of β-sitosterol reduced malondialdehyde (MDA) content significantly at 21 and 28 days of heat stress, and promoted the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) from 14 through 28 days of heat stress. β-Sitosterol effectively improved heat tolerance through suppression of leaf senescence in creeping bentgrass exposed to heat stress in association with the alleviation of membrane lipid peroxidation and activation of the enzymatic antioxidant system.

Adsorptive treatment of phenol from aqueous solution using chitosan/calcined eggshell adsorbent: Optimization of preparation process using Taguchi statistical analysis

Phenol and its derivatives are known to be toxic causing adverse impact on human health and environment. Adsorption utilising waste materials is a cost effective method for abatement of such pollutants. The present study thus aims to remove the phenol from aqueous solutions using chitosan/calcined eggshell adsorbent. Taguchi L27 Orthogonal array design methodology was used for the optimization of preparation variables. The statistical results obtained using ANOVA and S/N ratios showed that adsorption of phenol was significantly influenced by activation temperature (54.90%) and activation time (43.70%) whereas the mix ratio had fairly low impact on the output response (1.14%). The confirmation run in optimum preparation conditions of temperature (800 ​°C), time (60mins) and mix ratio (1:1) resulted in maximum adsorption capacity (10.82 ​mg/g) which confirmed that the optimization done by Taguchi model was valid and reliable. The characterization of adsorbent prepared under optimum conditions were done using scanning electron microscopy, X-ray diffraction (XRD), and the Fourier transform Infrared spectroscopy (FTIR). Adsorption and kinetic studies manifested that the adsorption phenomenon onto prepared adsorbent is illustrated well by linear Langmuir isotherm and pseudo second order kinetics.

Simulation of heat transfer in a turbocharger bearing housing

Modern world trends in engine building are characterised by the production of forced engines. The most popular and promising forcing method is the use of a turbocharger. The efficiency of journal bearings determines the reliability of TCR, which should be structurally simple, compact, reliable and inexpensive, while providing acceptable characteristics of rotor dynamics, noise, vibration and stiffness speeds. The best performance of the bearing unit is achieved with hydrodynamic lubrication, which depends on optimal operating and temperature conditions. The maximum operating temperature of the bearing assembly must be taken into account at the design stage. The purpose of this article is to develop an algorithm for calculating the heat transfer in the turbocharger bearing housing in order to assess the effect of the thermal state of the radial bearing on its performance and on the dynamics of the rotor. The simulation was carried out in the ANSYS software package and the developed software. The boundary conditions for the calculation were obtained from experimental data. The result of the simulation was the determination of temperatures and thermal fields in the turbocharger housing, as well as the values of the change in clearances under the influence of thermal expansion of parts. Verification of the results was carried out on the basis of comparison with the results obtained by other authors. Conclusions were drawn about the effect of thermal deformations on the rotor dynamics and the hydromechanical characteristics of the bearing.

Structural and gas-sensitive characteristics of thin semiconductor PdO films of various thicknesses during ozone detection

PdO films were obtained by thermal deposition of palladium metal with a thickness of 30 and 90 nm, followed by its oxidation in air at different temperatures. PdO oxide films are characterized by transmission electron microscopy (TEM) and reflection high-energy electron diffraction (RHEED). Data on the semiconductor properties and gas sensitivity to different concentrations of ozone in the air are obtained. The optimal temperature conditions for the oxidation of the films are established, which ensure their uniform phase composition and the absence of electrical noise during the detection of gases. The mechanism of the electrical noise appearance in ultrathin films associated with their fragmentation during oxidative annealing is proposed and justified. The possibility of detecting ozone impurities in the air below the maximum permissible concentration (MPC) by PdO semiconductor films is shown. Keywords: palladium oxide thin films, phase composition, electrical noise, gas sensor properties.

Improvement of the technology for railway wheel steel vacuum processing

The analysis of data on the production of wheel steel grades “2” and “T” according to GOST 10791-2011 in the conditions of the of the electric furnace shop of Ural Steel JSC is presented. The content of hydrogen and nitrogen is significantly less than the regulated ones on most heats, which indicates an irrational vacuum mode. Such modes lead to an increase in energy costs for redistribution. All this testifies to the available reserves for improving the vacuum technology. As a result of research, it has been determined that in order to guarantee the production of hydrogen content less than 1.5 ppm and nitrogen up to 0.007 %, it is necessary to carry out vacuum treatment of steel at a residual pressure in a vacuum chamber of up to 3 mbar, the duration of processing in a high vacuum is at least 20 minutes, and argon consumption is blowdown not less than 0.05 m3/t, metal overheating from 110 to 130 °С. The overheating range of the steel before the start of the vacuum treatment the optimal temperature conditions for casting the steel. The optimum temperature of metal overheating at the beginning of processing on steel degassing installation is ~ 115-125 °C with a duration of vacuum treatment of 50-55 minutes (loss of metal temperature 70-75 °C), with overheating of the metal in a steel-pouring ladle before the start of casting 35-45 °C and at loss of metal temperature during transportation to casting 5 °C (15 min). Regression equations are obtained that allow predicting the results of degassing, as well as selecting the values of the vacuum treatment parameters in order to achieve a given content of dissolved gases – hydrogen ([H], ppm) and nitrogen ([N], %).The research was conducted under financial support of the RF Ministry on Science and Higher Education (PROJECT No. FZRU-2020-0011).

Expression of IRT1 gene in barley seedlings under zinc deficiency at optimal and low temperatures

The deficiency or excess of zinc (Zn) cause negative effect on plant metabolism and development. Therefore, plants have established a tightly controlled system, including protein transporters to balance the uptake and utilization of metal ions. In this study, the relative expression of HvIRT1 gene, encoding the transmembrane protein IRT1 was analyzed in shoots and roots of barley (Hordeum vulgare ‘Nur’) under zinc deficiency at optimal (22 °C) or low (4 °C) temperatures. The Zn deficiency (0 μmol) caused an increase in HvIRT1 gene expression under both optimal temperature condition and cold. Although, the difference in mRNA content of HvIRT1 gene in roots of barley under optimal and low temperature was not observe. However, the HvIRT1 expression in leaves was higher at optimal temperature compare with cold condition. Moreover, long-term (7 days) of low temperature influence along with zinc deficiency leads to a significant decrease in the amount of HvIRT1transcripts in leaves, that corresponds to a decrease of photosynthesis rate and biomass accumulation. Overall, these findings suggest that HvIRT1 gene play an important role in plant’s response to zinc deficiency under optimal temperatures condition as well as at cold.

Enhancements provided by the use of an Ascophyllum nodosum extract can be transferred through archeospores in the red alga Neopyropia yezoensis (Ueda) L.-E. Yang & J. Brodie

The use of seaweed extracts as biostimulants to promote enhancements in other seaweed crops is gaining momentum. Here we examined if the seaweed-derived biostimulant Ascophyllum marine plant extract powder – AMPEP, enhanced growth and thermal tolerance of cultured thalli of Neopyropia yezoensis when grown under optimal and sub-optimal temperature conditions. We also examined if enhancements could be transferred to new blades through archeospore germination. Area, specific growth rate, reactive oxygen species (ROS) and protein content of thalli were measured as indicators of potential enhancement. The application of AMPEP significantly increased growth rates in thalli of N. yezoensis grown under optimal temperature conditions, whilst the thalli showed no indications of improved thermal tolerance. The collated data suggested that growth enhancement could be transferred from treated thalli to newly formed blades, which developed from archeospores. This study provides new evidence of the far-reaching potential of using extracts of selected seaweeds as biostimulants to support the cultivation of economically important Neopyropia species.

Thermodynamic modeling of iron recovery processes

One of the promising directions in metallurgy is the use of iron-containing waste, such as converter production sludge, iron-containing concentrates, rolling scale, iron ore processing waste and others. Development of new resource-saving technologies using such waste requires preliminary research and accumulation of information in the field of iron recovery. The paper considers the processes of iron recovery from oxides under various conditions. The authors used the method of thermodynamic modeling based on the search for the entropy maximum. The thermodynamic modeling tool was TERRA software package created at the Bauman Moscow State Technical University. TERRA complex is designed to calculate the thermodynamic properties and composition of the phases of equilibrium state of arbitrary systems with chemical and phase transformations. Using this software package, studies of the processes of iron recovery by various reducing agents (carbon, manganese, and silicon) in model thermodynamic systems were carried out, and optimal conditions for temperature and consumption of reducing agents were determined. The paper presents the results of a study of processes in the metal-slag system in equilibrium. The analysis of the metal-slag system equilibrium state was carried out for the temperature range of 1773 - 1973 K with different amounts of slag. Boundaries of the areas of redox processes were determined and the influence of metal components on conditions for iron oxides recovery from slag to metal was evaluated. The dependences of the system equilibrium composition on temperature at different ratios of metal and slag were obtained, as well as the optimal conditions for iron recovery.

Transformation of Selected Fusarium Toxins and Their Masked Forms during Malting of Various Cultivars of Wheat.

This study investigated the impact of malting of six wheat cultivars inoculated with Fusarium culmorum on the dynamics of content changes of selected Fusarium toxins. The grains of all the tested cultivars showed a high content of deoxynivalenol (DON), zearalenone (ZEN), and their derivatives, whereas nivalenol (NIV) and its glucoside were found only in the Legenda cultivar. Our experiments confirmed that the malting process of wheat grain enables the secondary growth of Fusarium, and mycotoxin biosynthesis. The levels of toxins in malt were few-fold higher than those in grain; an especially high increase was noted in the case of ZEN and its sulfate as the optimal temperature and pH conditions for the biosynthesis of these toxins by the pathogen are similar to those used in the grain malting process. This is the first paper reporting that during the malting process, biosynthesis of ZEN sulfate occurs, instead of glycosylation, which is a typical modification of mycotoxins by plant detoxication enzymes.

Ways to Increase the Durability and Reliability of Functional Units of Automotive Equipment

The operation of the engine in optimal temperature conditions provides the possibility of obtaining the highest indicators of its efficiency, namely, maximum output power; minimum fuel mixture consumption; increase in effective service life; increase in the reliability coefficient. (Research purpose) The research purpose is to substantiate the indicators for evaluating the efficiency of cooling systems of functional units used on automotive equipment. (Materials and methods) The introduction of surfactants with a fluorocarbon radical into the engine oil leads to an improvement in the operational characteristics of the functional units of machinery and power plants (power, specific fuel consumption and others), which is due to a decrease in hydrodynamic friction. (Results and discussion) When adding an antifriction additive to the engine oil, there is an increase in engine power and torque by 2.5-3.0 percent; reduction of specific fuel consumption by up to 6.9 percent, hourly fuel consumption by 3-4 percent; reduction of carbon dioxide emissions, improvement of fuel efficiency in the urban cycle by 2.6 percent, in rural by 2.8 percent, in mixed by 2.7 percent, reduction of acceleration time in the speed range of 80-130 kilometers per hour by 2.8 percent. (Conclusions) The organization of cooling processes of working units and heat carriers of their systems should be carried out taking into account the mutual influence of these components. This approach allows for the reconstruction of cooling systems both at the final stages of design and during operation. For the functioning of auxiliary cooling systems and the improvement of heat exchange, a detailed study and analysis of the operational processes of agricultural machinery are necessary. The creation of the most efficient cooling systems and conducting research using various lubricants requires consideration of the temperature- dynamic properties of cooling systems, taking into account the patterns of changes in their temperature modes and lubrication of functional systems depending on operating conditions and the environment, which will allow to identify the parameters of reliability of operability.

Optimal conditions of pH, composition, and temperature in synthesis of CdS thin films by chemical bath deposition technique

Optimal conditions of pH, composition, and temperature in synthesis of CdS thin films by chemical bath deposition technique

Ultrasound-assisted pressurized liquid extraction of anthocyanins from Aronia melanocarpa pomace

This work aimed to investigate the optimum conditions of pressure, temperature, ultrasound intensity, solvent concentration and solvent flowrate of ultrasound-assisted pressurized liquid extraction of anthocyanins from Aronia melanocarpa pomace. The novel setup operates with an aqueous solution of citric acid as extraction solvent. The optimization was performed in order to maximize the total anthocyanins content extracted from the pomace. The optimized conditions of 70 °C, 180 bar, a solvent concentration of 1.5 % wt. citric acid, in a 200 W ultrasound bath were obtained. These conditions resulted in 88.0 % wt. extraction of anthocyanins in 45 min. A kinetic study was performed to study the influence of the temperature on the total anthocyanin yield obtained at the optimal extraction conditions. Moreover, the component stability was assessed to prove that the system could successfully operate at 80 °C. Compared to classical batch extraction using the same solvent concentration and feedstock, the total anthocyanin content of the extract was increased by 19%.

Physico-chemical characteristics and aflatoxins production of Atractylodis Rhizoma to different storage temperatures and humidities

This study aimed to investigate the characteristics, moisture contents, chemical fingerprints changes and aflatoxins accumulation of Atractylodis rhizoma during storage, further to determine the optimum temperature and relative humidity conditions. Based on the suitable temperature (20–40 °C) and relative humidity (80–95%), 13 different temperature and humidity conditions were set up by the central composite design-response surface methodology (CCD-RSM) for Aspergillus flavus. After inoculation with Aspergillus flavus by artificial infection, A. rhizoma samples were stored under normal conditions and 13 different temperature and relative humidity levels. By taking the changes of characteristics, the contents of moisture, chemical fingerprints and aflatoxins as the evaluation indexes for A. rhizoma with or without Aspergillus flavus fungi to optimize the optimal storage conditions. After storage for 10 days, the color of A. rhizoma was deepened, the water content and chemical composition increased, and some unknown components were detected. The susceptible condition for aflatoxins production in A. rhizoma was identified at temperature 22–37 °C and relative humidity over 87.5%. Thus, the suitable storage conditions for A. rhizoma should be controlled at temperature below 20 °C and relative humidity less than 85%. This paper screened out the optimum temperature and humidity for the storage of A. rhizoma. Then, the storage specification for A. rhizoma was proposed, lying technical and data support for the scientific preservation of other food or herbs.

Modelling the thermal state of a turbocharger bearing housing when calculating the rotor dynamics at transient modes

PurposeThe reliability of various mechanisms and machines is determined by the durability of tribo-units, which must ensure operation at high temperatures and an extended range of rotor shaft speeds. The best performance of the bearing assembly is achieved with hydrodynamic lubrication, which depends on optimal operating conditions and temperature conditions. The purpose of this paper is determining the thermal state of the turbocharger (TCR) bearings.Design/methodology/approachThe simulation was carried out in the ANSYS Fluent software package. The boundary conditions for the calculation were obtained from experimental data. The experiments were carried out at a specialized stand created at the scientific and production association “Turbotekhnika”.FindingsThe result of the simulation was the determination of temperatures and thermal fields in the TCR housing. The data obtained testify to the uneven thermal loading of the bearings. When calculating the dynamics of the rotor, transient modes are considered. The results are the trajectories of the rotor in the space of the bearing clearance. The thickness of the lubricating layer was calculated as a parameter that determines the hydrodynamic friction regime. The thermal state of the TCR elements was evaluated at all the considered rotor speeds. The flexible axis of the rotor was obtained at different speeds.Originality/valueThe paper presents a model of heat transfer in a TCR housing and rotor dynamics, based on numerical methods, which will help in the design of TCRs and journal bearings.

Assembly of Glycochips with Mammalian GSLs Mimetics toward the On-site Detection of Biological Toxins.

According to our previously proposed scheme, each of three kinds of glycosphingolipid (GSL) derivatives, that is, lactosyl ceramide [Lac–Cer (1)] and gangliosides [GM1-Cer (2) and GT1b-Cer (3)], was installed onto the glass surface modified with Au nanoparticles. In the present study, we tried to apply microwave irradiation to promote their installing reactions. Otherwise, this procedure takes a lot of time as long as a conventional self-assembled monolayer (SAM) technique is applied. Using an advanced microwave reactor capable of adjusting ambient temperatures within a desired range, various GSL glycochips were prepared from the derivatives (1)–(3) under different microwave irradiation conditions. The overall assembling process was programed with an IC controller to finish in 1 h, and the derived GSL glycochips were evaluated in the analysis of three kinds of biological toxins [a Ricinus agglutinin (RCA120), botulinum toxin (BTX), and cholera toxin (CTX)] using a localized surface plasmon resonance (LSPR) biosensor. In the LSPR analysis, most of the irradiated GSL chips showed an enhanced response to the targeting toxin when they were irradiated under optimal temperature conditions. Lac–Cer chips showed the highest response to RCA120 (an agglutinin with β-D-Gal specificity) when the microwave irradiation was conducted at 30–35 °C. Compared to our former Lac–Cer glycochips with the conventional SAM condition, their response was enhanced by 3.6 times. Analogously, GT1b chips gained an approximately 4.1 times enhancement in their response to botulinum type C toxin (BTX/C) when the irradiation was conducted around at 45–60 °C. In the LSPR evaluation of the GM1-Cer glycochips using CTX, an optimal condition also appeared at around 30–35 °C. On the other hand, the microwave irradiation did not lead to a notable increase compared to the former GM1-Cer chips derived with the SAM technique. Judging from these experimental results, the microwave irradiation effectively promotes the installing process for all the three kinds of the GSL derivatives, while the optimal thermal condition becomes different from each other. Many bacterial and botanic proteinous toxins are composed of such carbohydrate binding domains or subunits that can discriminate both the key epitope structure and the dimension of glycoconjugates on the host cell surface. It is assumed that the optimal irradiation and thermal conditions are required to array these semi-synthetic GSL derivatives on the Au nanoparticles in a proper density and geometry for tight adhesion with each of the biological toxins.

Removal of boron in desalinated seawater by magnetic metal-organic frame-based composite materials: Modeling and optimizing based on methodologies of response surface and artificial neural network

A new type of metal organic frame-based magnetic composite adsorbent UiO-66-NH2/graphene oxide/Fe3O4 was used to eliminate the adverse effects of boron in the desalinated seawater. Through serial characterization, it was found that this adsorbent has the advantages of strong magnetic response, good pore structure and abundant functional groups. On the basis of single-factor experiments on various influencing factors, the simulation and prediction capabilities of the response surface method and artificial neural network method for the adsorption process were studied and compared. Both methods shown strong capacity to make effective prediction on the process of adsorption. However, the error of response surface method is smaller than the error of artificial neural network method. Result of optimization by response surface method shows that the optimal conditions of adsorbent dosage, pH, and temperature are 99.1 mg/L, 3.38 and 318 K. Following the above conditions, the boron adsorption capacity of the adsorbent obtained in the real desalinated seawater environment is 22.46 mg/g. In addition, the adsorbent shows good recyclability. Pseudo-second-order kinetic model, intra-particle diffusion model, and Langmuir isotherm model are all suitable for describing adsorption process. Thermodynamic research results reveal the fact that this process is spontaneous and endothermic, and the adsorption of boron by the adsorbent is a composite process consisting of physical adsorption and chemical adsorption.