OPTIMIZATION OF METHODS AND PARAMETERS OF PRE-START THERMAL PREPARATION OF THE ENGINE FOR STARTING DEPENDING ON THE AMBIENT TEMPERATURE

Due to the lack of a generally accepted methodology for calculating the starting processes of automotive diesel engines, today it is not possible to calculate their temperature parameters with a sufficient degree of accuracy during start-up, which determine the condition of a guaranteed start-up process. The main problem in applying theoretical calculations is that they take into account the compression ratio of the engine. But the compression ratio and the value of the actual pressure in the engine cylinders during the start-up are completely different indicators. The purpose of this work is to correct the generally accepted dependencies for determining the temperature parameters of a diesel engine by introducing a correction factor that takes into account the reduced pressure in the engine cylinders during start-up, as well as calculating the temperature parameters during start-up according to the proposed calculation method. The correction factor is determined experimentally and depends on the engine temperature. When applying the correction factor, it becomes possible to accurately calculate the temperature of the fuel-air mixture, which determines the possibility of a guaranteed start-up process and at the same time allows you to set the minimum necessary requirements for the means of thermal pre-start preparation. A group of graduate students and teachers (Izhevsk State Agricultural Academy and Kazan Agrarian University) conducted a number of practical studies on the basis of one of the leading agricultural enterprises of the Udmurt Republic JSC "Ilyich's Way". The MTZ-82 tractor was taken as the object of the study. The subject of the study was the launch of its D-243 engine at low temperatures in real operating conditions. The choice of this model of diesel engine is due to its wide application on tractors. The studies were carried out according to the approved test program, which consists in starting the D-243 engine of the MTZ-82 tractor at temperatures from - 30 ° C with an interval of 5 ° C to +5 ° C (engine temperature is equal to ambient temperature), as well as from +5 ° C to +90 ° C with an interval of 20 ° C (ambient temperature +20 ° C). Measurements were carried out to determine the amount of compression in the engine cylinders and the speed of rotation of the crankshaft at certain temperatures. The experiments were carried out using a starter charger that provides the full electric power of the diesel starter. As a result of the experimental work carried out, a change in the value of the correction coefficient from the engine temperature was established, and in accordance with the modified methodology of theoretical calculations, the values of the temperature of the fuel-air mixture at the end of the compression stroke of the diesel engine at start-up are given. It is established that the minimum required pre-start temperature of the diesel engine should be at least +5 ° C. Based on the results of the analysis of calculations, the directions of ensuring a guaranteed start of the diesel engine by simultaneously heating the coolant and engine oil are proposed. These requirements can be provided by a thermal storage system that does not require additional energy sources for its operation

Cytotoxicity Effect and Morphological Changes of Chrysanthemum Morifolium Methanolic Extract against Chronic Myeloid Leukaemia K-562 Cell Line

Chrysanthemum morifolium, also known as “Bunga kekwa” in Malaysia, has various benefits and widely used in Chinese herbal medicines. The plant extract was reported to have significant biological activities, such as anti-inflammation, anti-tumour, anti-oxidant, and anti-cancer. Nonetheless, its anti-cancer potential on chronic myeloid leukaemia has remained elusive. The main goal of this study is to evaluate the cytotoxic effect of C.morifolium buds and flowers in methanolic extracts on chronic myeloid leukaemia malignancy K-562 cell lines. The bud and flower of C.morifolium were macerated for 72 hours in 100% methanol then were concentrated under reduced pressure using a rotary evaporator and oven-dried to obtain crude extracts. K-562 cells were treated with six different concentrations 400, 200, 100, 50, 25, and 12.5 µg/ml and incubated for 24, 48 and 72 hours. The in vitro cytotoxic activity was measured using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) test and was quantified using a microplate reader at 570 nm. Acridine orange and propidium iodide (AO/PI) staining were used to assess morphological alterations. MTT assays results showed moderate toxicity of both extracts. The lowest maximal half inhibitory concentration (IC50) value were observed at 72 hours of incubation; 182 ± 4.04 ug/ml for BM and 161 ± 7.88 ug/ml for flower extract (FM). However, there was a significantly different IC50 value (p<0.05) between the incubation periods of both treatments where the IC50 value at 24 hours was 301.33 ± 8.51 ug/ml 301 µg/ml in BM, 216 ± 10.79 ug/ml 216 µg/ml in FM and at 48 hours was 227 ± 12.25 ug/ml 227 µg/ml in bud extract (BM), 174 ± 11.92 ug/ml 174 µg/ml in FM. The morphological changes evidence was shown in AO/PI staining by the appearance of a mixed population of cells; early apoptosis, late apoptosis and necrotic cells. These findings suggested that methanolic C.morifolium extracts showed moderate cytotoxic effect on chronic myeloid leukaemia K-562 cells. Further study needed to identify the mode and mechanism of cell death in K-562 cells treated with the C.morifolium extracts.

Experimental Data of Grinding Dried Fibrous Plant Materials

Introduction. Developing a method for energy-efficient grinding of fibrous vegetable raw materials to avoid the clogging of grids remains an urgent task. The aim of the research is to study the process of grinding dried fibrous plant materials and to estimate the influence of the device operating characteristics on the quality of grinding and the process energy intensity. Materials and Methods. The experimental apparatus is a rotor grinder. Its working bodies are alternate knives and hammers. When a hammer is in motion, its triangle side creates the reduced pressure area. There was studied the influence of the linear velocities of knife motion and of feed of raw materials on fractional composition of the grinded materials, grinder productivity, and grinding specific energy capacity. Results. It is found that the change in the fractional composition of the grinded product occurs when the speed of the rotor knives increases. Optimal range of knife speed for producing the product of the required fractional composition is 55‒75 m/s. The increase in the speed leads to increasing productivity, but is accompanied by the growth of specific power intensity. If the rotor speed is constant, the increase of raw material feed increases the grinder productivity, but only up to a certain value. After that, the productivity decreases because of excessive filling of the working chamber with raw materials and clogging of the grates. For each value of the knife speed, there is an optimal feed that ensures the maximum productivity. High values of knife speed lead to significant energy intensity of the process and overgrinding of raw materials. Therefore, the optimal range of knife speed is 55‒65 m/s. Discussion and Conclusion. Effective grinding of raw materials is achieved through lower energy capacity of grinding process and absence of grate clogs resulted from separating particles from the surface of plants to be grinded.

“A Little Bit Closer”: A Mixed Method Analysis of the Effect of the COVID-19 Pandemic on the Lives of Adolescent Parents

Using a Family Stress Model framework, we used quantitative and qualitative methods to investigate the impact of the pandemic on Latinx pregnant and parenting adolescents and their families. Participants were 406 adolescents (ages 14–19) in the southwestern U.S. who participated in a school-based relationship education program for pregnant and parenting adolescents. In the quantitative analysis, we compared self-reported mental health (depressive symptoms, worry, parental stress), coparental relationships (conflict and communication), and parenting of adolescents who participated prior to the pandemic ( N = 357; 83.6% female; 84.7% Latinx) with those who participated during the pandemic ( N = 49; 74.6% female; 87.8% Latinx). Unexpectedly, the pandemic-period cohort reported fewer depressive symptoms, less parental stress, more frequent coparental communication, and more positive coparental communication and conflict management than the pre-pandemic cohort. For the qualitative analysis, we conducted focus groups and individual interviews with 21 adolescent parents (95.2% female; 90.5% Latinx) from the pandemic-period cohort and analyzed the data using thematic analysis. Participants reported many negative effects of the pandemic including increased economic and health stress, yet also discussed reduced pressure with school and more time with family members. These findings have important implications for enhancing the well-being of adolescent parents and their children after the pandemic.

Decision making in control systems based on data analysis

Technological processes are always accompanied by deviations from the set mode, which is due to the influence of many external and internal factors. The environmental parameters, the components of input raw materials, and the condition of technological equipment are constantly changing, which requires solving the problem of finding the optimal control parameters and, in some cases, the parameters of the process itself. Most industries are focused on obtaining the final product with a given level of quality. Changes in parameters of the technological process may deteriorate the quality of production and cause defects or even emergency situations. To prevent this, forecasting methods are used. The task of constructing predictive models based on experimental data is relevant for a wide range of technological processes. Today, predictive models are widely used in management, diagnosis and identification. The vast majority of these models are based on artificial intelligence technologies or methods of mathematical statistics. The most widespread forecasting models find application in areas such as banking, insurance, business economics, medicine, diagnostics of technical components and equipment, and forecasting the parameters of technological processes. Despite the well-developed algorithm for model development and application, the main problem that remains is to acquire data, select an appropriate model structure, and integrate the model into existing control systems. The paper will predict the parameters of the technological process of methanol production under reduced pressure. The production of methanol under reduced pressure is a multi-stage process, and the emergence of problems at some stage will adversely affect further work and the end result. Note that there are all problems related to the performance of technological processes in the production of methanol, which are described above. Therefore, another task is to forecast emergencies, taking into account the indicators of all stages in the process. The development of models for forecasting emergencies and controlling thermal regimes and their further integration into the existing automatic process control system is proposed to be performed according to the principles of industrial revolution – Industry 4.0. Important components of Industry 4.0 are the Internet of Things, data analysis, and digital duplicates. Each of these components solves a partial problem and, collectively, they provide full automation of production, forecasting of real-time process indicators, and calculation of optimal control. The process of methanol production under reduced pressure can be fully automated in accordance with the components of Industry 4.0. First, there is instrumentation that allows the values of technological process to be obtained over time. Second, given a moderate size of these data, one can obtain models of control objects, perform their software implementation, and use them to calculate optimal control or predict the state of the process. The paper proposes a variant of constructing a virtual model based on experimental data and its further use with actual values ​​of process parameters. A regression model was chosen to develop a model for predicting the temperature regime. Regression analysis allows checking the statistical significance of the parameters, assessing the adequacy and accuracy of the model, and establishing the nature and closeness of the relationship between the studied phenomena. It is also important to predict the occurrence of emergency (adverse) situations at the workplace. For this purpose, it is necessary to determine a list of these situations according to the technological regulations and develop a model for forecasting emergencies. There are various forms of presenting a model for forecasting emergencies. A decision tree is one of them. It will be developed for the production of methanol. The resulting tree is a graphical structure of the verbal (semantic) model relying on the expert's reasoning in solving problems related to emergencies. This is a network structure, whose nodes indicate potential deviations of the control object from the normal mode of operation. The resulting tree is used to solve forecasting and diagnosing problems. For practical use, the decision tree is implemented in software as an "if - then" set of rules. The software is used as an element of a higher-level system in relation to the existing automatic process control system.

Retrieval of High Added Value Natural Bioactive Coumarins from Mandarin Juice-Making Industrial Byproduct

Cold pressed essential oil (CPEO) of mandarin (Citrus reticulata Blanco), a by-product of the juice-making industrial process known to contain large amounts of polymethoxyflavones, was exploited for its content in high added value natural coumarins. The study herein afforded a method referring to the evaporation of CPEO volatile fraction under mild conditions (reduced pressure and temperature below 35 °C) as azeotrope with isopropanol. This allowed the isolation of high added value coumarins from the non-volatile fragment using preparative High Performance Liquid Chromatography (HPLC). Pilot-scale application of this procedure afforded for each kg of CPEO processed the following natural bioactive coumarins in chemically pure forms: heraclenol (38–55 mg), 8-gerayloxypsoralen (35–51 mg), auraptene (22–33 mg), and bergamottin (14–19 mg). The structures of coumarins were verified by Nuclear Magnetic Resonance (NMR) spectroscopy and HPLC co-injection with authentic standards. Thus, the low market value mandarin CPEO with current value of 17 to 22 EUR/kg can be valorized through the production of four highly bioactive natural compounds worth 3479 to 5057 EUR/kg, indicating the great potentials of this methodology in the terms of the circular economy.

Extraction and Identification of Phenolic Compounds from the Iraqi Heliotropium europaeum L. plant

The plants of genus Heliotropium L. (Boraginaceae) are well-known for containing the toxic metabolites called pyrrolizidine alkaloids (PAs) in addition to the other secondary metabolites. Its spread in the Mediterranean area northwards to central and southern Europe, Asia, South Russia, Caucasia, Afghanistan, Iran, Pakistan, and India, Saudi Arabia, Turkey, and over lower Iraq, Western desert. The present study includes the preparation of various extracts from aerial parts of the Iraqi plant. Fractionation, screening the active constituent, and identification by chromatographic techniques were carried out.Heliotropium europaeum herbs were first defatted with n-hexane then extracted exhaustively by soxhlet apparatus using absolute methanol. The extract was filtered and the solvent was evaporated by applying a reduced pressure by a rotary evaporator. The residue suspended in distilled water and partitioned with chloroform, ethyl acetate, n-butanol. The hydrolysis step was done for the two fractions (n-butanol and ethyl acetate). Phytochemical analysis for the screening and identification of bioactive substances of the Heliotropium europaeum plant was done for each fraction. The identification of n-butanol and ethyl acetate fractions was carried out by thin-layer chromatography (TLC) and HPLC technique. For quantitive analysis, the concentration was calculated by serial concentrations of external standard materials to build a calibration curve between concentration and its equivalent peak area. The outcomes of this study were the identifications of new six phenolic compounds from H. europaeum ethyl acetate fraction, which exhibited wide biological activity. The identified compounds were kaempferol (1), Silybin (2), caffeic acid (3), Genistein (4), Apigenin (5), in addition to syringic acid (6). In the present study, we regard the first to report such results about the phenolic compounds in H. europaeum extract. A total of six discovered phenolics were identified in this extract for the first time. Our results on H. europaeum constituents provide a scientific base to examine the pharmacological effects of this plant in the future.

Changes in Crystal Structure and Accelerated Hydrolytic Degradation of Polylactic Acid in High Humidity

Highly crystallized polylactic acid (PLA) is suitable for industrial applications due to its stiffness, heat resistance, and dimensional stability. However, crystal lamellae in PLA products might delay PLA decomposition in the environment. This study clarifies how the initial crystal structure influences the hydrolytic degradation of PLA under accelerated conditions. Crystallized PLA was prepared by annealing amorphous PLA at a specific temperature under reduced pressure. Specimens with varied crystal structure were kept at 70 °C and in a relative humidity (RH) of 95% for a specific time. Changes in crystal structure were analyzed using differential calorimetry and wide-angle X-lay diffraction. The molecular weight (MW) was measured with gel permeation chromatography. The crystallinity of the amorphous PLA became the same as that of the initially annealed PLA within one hour at 70 °C and 95% RH. The MW of the amorphous PLA decreased faster even though the crystallinity was similar during the accelerated degradation. The low MW chains of the amorphous PLA tended to decrease faster, although changes in the MW distribution suggested random scission of the molecular chains for initially crystallized PLA. The concentrations of chain ends and impurities, which catalyze hydrolysis, in the amorphous region were considered to be different in the initial crystallization. The crystallinity alone does not determine the speed of hydrolysis.