Mathematical Planning Of Experiment Research Articles

Определение оптимальных параметров выщелачивания фтора из угольной части отработанной футеровки демонтированных электролизеров производства алюминия

When aluminum is obtained by electrolysis of cryolite-alumina melts when the baths are sent for capital repairs, a solid technogenic product is formed – waste lining of electrolytic cells (WLEC). The volume of formation of WLEC is 30-50 kg per 1 ton of aluminum. Currently, it is mainly stored at landfills near industrial enterprises, causing harm to the environment. However, this technogenic raw material contains valuable components (fluorine, aluminum, sodium) that can be extracted to produce fluoride salts, which are in demand during the electrolytic production of aluminum. The objects of research were samples of the coal part of the waste lining of dismantled S-8BM (E) type electrolytic cells of «RUSAL Krasnoyarsk» JSC (Krasnoyarsk) of RUSAL company. According to the X-ray experiment diffraction analysis (using a Bruker D8 ADVANCE diffractometer) of the phase composition of the samples, it was found that the main fluorine-containing compounds are cryolite, chiolite, sodium and calcium fluorides. The total fluorine content in the studied samples averaged 13.1 %. We conducted studies on the leaching of fluorine from WLEC with a solution of caustic alkali (NaOH concentration – 17.5 g/dm3). The process was carried out in a mechanically agitated reactor using a BIOSAN MM-1000 top drive laboratory stirrer with a two-blade nozzle. By the method of mathematical planning of a three-factor experiment, the mutual influence of three leaching conditions on the optimization parameter was established – the extraction of fluorine in solution (in percent). The maximum recovery of fluorine from WLEC to the leach solution averaged 86.4 % and was achieved with the following indicators:processtemperature–95°C,theratio ofliquidtosolidphase–9:1,duration– 210 min.

Motor Skills Development: Optimization of Teaching Boys Aged 14

The study objective is to substantiate the modes of alternation of physical exercises and rest intervals in the process of teaching series of tasks aimed at motor skills development in boys aged 14 years. 
 Materials and methods. The participants in the study were 40 boys aged 14. The children and their parents were fully informed about all the features of the study and gave their consent to participate in the experiment. To achieve the objective set, the following research methods were used: study and analysis of scientific and methodological literature; pedagogical observation, timing of training tasks; pedagogical experiment, methods of mathematical statistics, methods of mathematical experiment planning.
 Results. The results of the analysis of variance and regression models show that the optimal mode of performing series of training tasks is within the range of 6-12 exercise repetitions with rest intervals of 60-120 seconds. In the proposed matrix of factorial design, the selected step of factor variation is sufficient to study the impact of different modes of physical exercises on the effectiveness of teaching children and adolescents. 
 Conclusions. A 22 type experiment made it possible to examine the multifactorial structure of the process of teaching boys aged 14, using the program of algorithmic instructions, to specify the optimal balance between factors for their use when teaching physical exercises during physical education classes.
 The best options for teaching series of tasks to boys aged 14 during physical education classes are: series 1 — 12 repetitions, rest interval of 120 s; series 2 — 12 repetitions, rest interval of 60 s; series 3 — 6 repetitions, rest interval of 60 s; series 4 — 12 repetitions, rest interval of 60 s; series 5 — 12 repetitions, rest interval of 120 s; series 6 — 6 repetitions, rest interval of 60 s.

Strength Abilities: Estimation of Immediate Training Effect of Strength Loads in Girls Aged 7 Years

The study purpose was to experimentally substantiate technological approaches to estimating training effects of strength loads in girls aged 7 years.
 Materials and methods. The study participants were girls aged 7 years (n = 40). The children and their parents were fully informed about all the features of the study and gave their consent to participate in the experiment. To solve the tasks set, theoretical and empirical methods were used: analysis and generalization of scientific and methodological literature; modeling, pedagogical observation and experiment, methods of mathematical experiment planning (2k type FFE).
 Results. The study results show that in the proposed matrix of the 22 type full factorial experiment design, the chosen step of variation of factors is sufficient to study the influence of different modes of strength exercises on the dynamics of ITE in girls aged 7 years.
 Conclusions. At station 1 (exercises to strengthen arms and shoulders), the ITE in girls aged 7 is most influenced by the interaction between the number of repetitions in a set and the rest interval (x1x2) – 83%, the number of repetitions in a set (x1) – 15%; at station 2 (exercises to strengthen abdominal muscles), it is most influenced by the number of repetitions in a set (x1) – 48.5%, the rest interval (х2) – 48.5%; at station 3 (exercises to strengthen back muscles) – by the rest interval (x2) – 82%; at station 4 (exercises to strengthen leg muscles) – by the rest interval (x2) – 92%. At stations 1–3, to strengthen the ITE, it is necessary to increase the number of repetitions in a set and the duration of the rest interval, at station 4, it is necessary to increase the number of repetitions in a set and to reduce the duration of the rest interval.

Prognostic potential of mathematical experiment planning

The ground-experimental testing of the elements of space technology is a crucial stage in the creation of space products, in fact, this is the ground «flight» of the devices being created. And how well the operating conditions will be reproduced at this stage and the successful functioning of the devices under the expected conditions is ensured, its successful operation in real flight during the service life depends. Electronic equipment (apparatus) of the spacecraft is one of the essential elements that ensure the fulfillment of target tasks, which should confirm their readiness for the forthcoming work at the stage of ground-based experimental testing. The technology of experimental development at a time when the scientific and production association of applied mechanics (now the JSC Academician M. F. Reshetnev Information Satellite Systems) was part of the circle of enterprises that created space technology. And at the same time, the peak of research and implementation in the engineering practice of mathematical experiment planning turned out to be very timely. There was a backlog of applied work in various branches of science and technology and a minimum of work on radio-electronic topics, since the element base of the latter did not allow managing the internal parameters of electronic components, i. e., to reveal the influence of internal factors. This became an obstacle to the implementation of the capabilities of the method in research and improvement of electronic equipment. The article shows how the developers of the enterprise equipment overcame the existing limitations and successfully applied mathematical planning of the experiment for the first time in Russian space technology. Using the capabilities of the methodology, the tasks of optimization of circuit design and design implementation of devices, the choice of the element base for space equipment, the establishment of tolerances and the formation of test modes, etc. were solved.

Antifungal and antibacterial effects of newly created lactic acid bacteria associations depending on cultivation media and duration of cultivation

BackgroundThe newly created associations of lactic acid bacteria (LAB) isolated from Armenian dairy products (yoghurt, sour cream and different varieties of cheese), as well as from the gastrointestinal tract of honeybees were screened according to their antifungal and antibacterial activity.ResultsLAB strains were mixed at equal proportions (1:1) according to mathematical planning of experiments. Antifungal and antibacterial effects of different combinations (associations) were determined in different media, employing well-diffusion and total diffusion into agar methods. A number of fungal and bacterial test-organisms, including pathogenic ones, were used. Pure LAB strain cultures were used as a control. The antifungal effect of the most active strain Lactobacillus rhamnosus MDC 9661 in the associations with other LAB strains was partly decreased. At the same time, some mixed LAB cultures in DeMan, Rogosa and Sharpe (MRS) medium demonstrated significant antibacterial activity against wide spectra of test-organisms only in the case of simultaneous cultivation of LAB strains. On the other hand, in the case of different LAB strains cultivated in MRS with 24-h time break between mix formations by different strains, no inhibitory activity was revealed. But the inhibitory effect of many LAB associations against test-organisms was significantly increased in the case of separated cultivation in milk.ConclusionThe inhibitory effect of mixed LAB associations showed stronger dependence on the cultivation media and on the duration of cultivation with respect to each other. The co-cultivation of some strains, like L. rhamnosus MDC 9661, could lead to changed antagonistic activity. Consequently, the results are significant for creation and further investigation of LAB associations, as effective probiotics, and for their probable application in the production of antimicrobial preparations.

Assessment of reliability and criteria for improving the quality of rock cutting equipment of tricone drilling bits for well-boring especially hard rock

One of the options for solving the problem - a comprehensive improvement in the quality of the bit was proposed. The most widespread damages that are caused by premature failure of the rock cutting equipment of tricone rock drilling bit when we have been process well-boring by especially hard rocks are analyzed. The main idea is to develop a step-logical model. Such model is created on the basis of reasons that bring to a failure of tricone drilling bit, which are rock cutting equipment. It is prescribed that the failure of rock cutting equipment is the reason of the logical sequence of the most probable events, and the criterion of failure is the minimum cross-section in the failure model. This article presents a stepwise logical analysis, which makes it possible to establish the nature of the relationship between the basic factors that are taken into account when making decisions. Researches were conducted on the basis of mathematical planning of experiments in the real production of drill bits. One example is shown of how modules can be used that describe one of the possible reasons for the failure of a rock cutting equipment's tricone drilling bit. The three main factors are the basic events. This is determined by the analysis that in all cases, in the failure models of the bit. These main factors are the initial material properties and design parameters set at the design and construction stage, as well as technological factors that are formed at the stages of design and implementation of manufacturing processes. A step-by-step analysis makes it possible to detect the relationship between under control factors and failures. A scheme is proposed for determining the parameters of technological system element, with the help of which it is possible to establish quality indicators of insert rock cutting equipment of tricone drilling bits. The choice of the optimal variant of parameters is carried out in accordance with the criterion of maximum efficiency. Thus, the application of step-logic models makes it possible not only to find out the reasons for the failure of rock cutting equipment for tricone drilling bit, but also to make correct and substantiated decisions for quality assurance of processes at the main stages of the lifecycle for manufacturing tricone drilling bit.

ASSESSMENT OF THE METABOLITE OF CHLORORGANIC POLLUTANTS CONTENT IN URINE OF WORKERS OF POLYVINYCHLORIDE PRODUCTION

Introduction. The control and study of changes in the composition of biomedical samples under the influence of toxicants makes it possible to carry out early diagnostics, to reveal occupationally caused diseases. Vinyl chloride (VC) is a compound widely used in the chemical industry, the production of which is continuously growing all over the world, as well as the number of workers employed in it. Thiodiacetic acid (TDAA) is the main metabolite of vinyl chloride and its urinary excretion is associated with its level of exposure. Material and methods. The study was conducted in a linked sample of 19 workers in the dynamics of two-day 12-hour shifts after a three-day weekend. For 10 workers from this group, a more in-depth study of the dynamics of TDАА excretion before and after the shift was carried out: three 12-hour shifts. The analysis of TDAA in urine was carried out by chromatography-mass spectrometry using an Agilent 7890A gas chromatograph with an Agilent 5975C mass-selective detector. To find the optimal parameters for temperature, reaction time, catalyst type, mathematical planning of the 3-factor experiment was carried out. The identification of the TDAА derivative on mass chromatograms was carried out by the absolute retention time (10.36 min) and the intensity ratio of the peaks of the detected ions (146, 178). Results. Studies have shown average levels of TDAA in the urine of professional groups of workers (apparatchiks, cleaners) to be significantly higher before the next shift (12 hours after the end of the previous shift) than at the end of the previous shift and 1.99 times for operators (p = 0.004) and 2.61 times for cleaners (p = 0.002). Further, there was a significant decrease in the average level of TDAA in the urine relative to the beginning of the shift: 1.72 times for operators (p = 0.006) and 1.62 times for cleaners (p = 0.003). Conclusion. This analyte can be considered as an informative indicator of the presence of the production effect of VC from the point of view of evidence-based medicine, further confirmation of the need for studies of markers in persons in contact with this toxicant.

Pattern Recognition: Motor Skills Development in Girls Aged 15

The study objective is to determine physical exercises modes when developing motor skills in girls aged 15.Materials and methods. The participants in the study were 40 girls aged 15. To achieve the objectives set, the following research methods were used: study and analysis of scientific and methodological literature; pedagogical observation, timing of training tasks; pedagogical experiment, methods of mathematical statistics, methods of mathematical experiment planning, discriminant analysis. To achieve the objective set, the study examined the effect of different variants of performing exercises, specifically: the number of repetitions (x1) and rest intervals (x2) on mastering a press headstand technique. The girls aged 15 were divided into four groups according to the experiment plan. During the learning process, a method of algorithmic orders was used. The student could proceed to the next exercise only after a correct performance of the previous exercise on three consecutive attempts. The number of repetitions needed to teach exercises in each series of training tasks was recorded. The level of proficiency in the physical exercises performance was determined by the alternative method: “performed” or “failed”. A technically correct performance of the exercise gave the students “1” point; a failure to perform the exercise gave them “0” entered in the protocol.Results. The 22 type experiment made it possible to study the multifactorial structure of teaching the girls aged 15, using a program of algorithmic orders; to specify optimal correlations of factors for their use when teaching physical exercises during physical education classes; to collect data for the calculation of regression models of teaching separate series of training tasks and for discriminant analysis to obtain a generalized model of teaching an exercise in general.Conclusions. To select a generalized mode of exercises of the series of tasks when teaching girls aged 15 a press headstand and handstand, the first discriminant function can be used with an emphasis on the most informative variables.The regression equations obtained from the analysis of the 22 full factorial experiment data make it possible to specify and select the most effective modes of exercises for mastering separate series of training tasks.

DETERMINATION OF THE OPTIMAL EXTRACTION CONDITIONS OF DANDELION HERB AND LARGE BURDOCK LEAF SPECIE BY METHODS OF MATHEMATICAL PLANNING OF A MULTIFACTORIAL EXPERIMENT

Introduction. Use of medicinal species at home entails some inconvenience. Therefore, it is topical to obtain phytopreparations, in particular dry extracts, from medicinal plant raw materials. This ensures the maximum yield of a complex of biologically active substances, and simplifies the way of its application, dosing and storage. The department of pharmacy of the Altai State Medical University has developed a specie of the following composition: dandelion medicinal herb and large burdock leaf (1:1). On the basis of this species, a technology for obtaining the dry extract is being developed. Variety factors influence on the output of a complex of biologically active substances from plant raw materials: the technological properties of raw materials, the methods and conditions for carrying out the extraction process, and the equipment used. Aim. To determine the optimal conditions for extracting a specie of dandelion herb and a large burdock leaf. Materials and methods. To solve this problem, methods of mathematical planning of a multifactorial experiment have been used: simplex method of mathematical planning, incomplete factorial experiment of type 25-2 for compiling the equation of the response surface, the method of steep ascent (the Box – Wilson method) along the response surface. Based on the theoretical basis of extraction, parameters and factors of process optimization were chosen, intervals of their variation are indicated. Variable factors – shredding, the ratio of «raw materials : extractant», time of maceration, temperature and the number of maceration. The extraction was carried out by remaceration, aqua purificata serves as extractant. The parameter of optimization was the exhaustion of the specie of extractive substances. Results and discussion. As a result of the simplex method, a number of studies were carried out until the area of the supposed optimum was reached. To describe the experiment in the region of the optimum and to compose the equation of the response surface, an incomplete factor experiment of the type 25-2 were put. A linear equation of the extraction process were obtained and the adequacy of the work of the obtained mathematical model is proved. To refine the extraction conditions and establish the optimal extraction regime, the method of steep ascent on the response surface was used. Conclusion. As a result of the experiment, optimal extraction conditions were established: crushing – 2 mm, ratio «raw material : extractant» – 1:10, time of maceration – 30 minutes, number of maceration – 3, temperature – 100 °С. These results will be used in the development of technology and the technological scheme for obtaining the dry extract of the specie.

Hydrochemical Investigation of Dissolving Sulfide Gold-Bearing Raw Material of Uderey Deposit

This article describes a method for the hydrochemical dissolution of a sulfide gold-bearing raw material from the Uderey’s deposit using nitric acid. The chemical and phase compositions of the studied material, mainly represented by compounds of silicon, sodium, arsenic, iron and sulfur, are investigated. Phase composition: pyrite, arsenopyrite, quartz, thenardite. The dependences of the influence of temperature, time, and the liquid to solid ratio on extracting the main components in the solution were determined by methods of mathematical experiment planning. The calculated values ​​of the determination coefficients testify to the adequacy of the chosen two-level model. The optimum parameters of the process were obtained: L/S ratio = 8; the nitric acid concentration was 6 M; experiment duration was 75 minutes.

Property Modelling and Durability of Composite Materials

Composite materials are considered as complex systems with corresponding system attributes. The necessity of studying the properties and structure of composite materials as a whole as systems connected by relationships that generate integrative qualities is pointed out. When synthesizing a composite, it is proposed to use the principle of simulability: a complex system is represented by a finite set of models reflecting a certain facet of its essence. This makes it possible to investigate a certain property or group of properties of a building material using one or several simplified (narrowly-oriented) models. Identification of new properties and entities is done on the basis of building up a set of simplified models (the reflection of a complex system as a whole is provided by the interaction of simplified models). Using the principle of purposefulness makes it possible to describe the quality of the material by some functionality for an integrated system. Internal causal relationships, the existence and function of the composite material (system) are based on the principle described physicality (any system regardless of the inherent physical laws of nature, possibly unique); no other laws are required to describe the operation of the system. The study of material properties is made on the basis of parametric identification of kinetic processes of formation of physical and mechanical characteristics of composite materials. For special purpose building materials, a number of particular criteria (properties) are determined, and their description is formalized using the principal component method (reducing the dimensionality of problems in assessing the quality of a material with simultaneous determination of a set of independent partial criteria). The results of the practical application of the method for evaluating the quality of composite materials with special properties are presented. Among the priority criteria were: strength, density and porosity of the material. Their dependences on the coded volume fractions of aggregate and filler were obtained by methods of mathematical experiment planning. It is shown that for most properties one can confine oneself to second-order differential models; each of the properties of the composite is considered as one of the particular criteria. Appendices are given to the development of composite materials for various purposes. Using the methods of control theory, an analytical description of the durability of the composite material is given; parametric identification is reduced to the determination of time constants in a second-order differential model, taking into account their dependencies on the prescription and technological parameters. Assessment of durability of a radiation protective composite taking into account dependences of the main properties on the prescription and technological parameters received on the basis of the generalized model is made.

Pattern Recognition: Physical Exercises Modes During Motor Skills Development in Girls Aged 14

The study objective is to determine physical exercises modes when developing motor skills in girls aged 14.
 Materials and methods. The participants in the study were 40 girls aged 14. To achieve the objective set, the following research methods were used: study and analysis of scientific and methodological literature; pedagogical observation, timing of training tasks; pedagogical experiment, methods of mathematical statistics, methods of mathematical experiment planning, discriminant analysis. Results. The first canonical function explains 73.3% of the variation in results, the second function – 21.6%, which indicates their high informativity (r1=0.898; r2=0.743). The analysis of canonical functions highlights the statistical significance of the first and second canonical functions (λ1=.067; р1=0.001; λ2=0.346; р2=0.001). The first and second functions have a high discriminative ability and value of interpretation with respect to the general totality. The number of repetitions for mastering the first and fourth series of training tasks has the largest contribution to the first canonical function. This indicates that the exercises for developing motor abilities and teaching to control movement time and muscular effort influence the effectiveness of teaching a press headstand and handstand. The number of repetitions for mastering the second and third series of training tasks has the largest contribution to the second canonical function. This indicates that starting and ending positions, and actions without which the exercise performance is impossible influence the effectiveness of teaching a press headstand and handstand.
 Conclusions. The discriminant function structure coefficients show that the training program effectiveness is determined by selecting the series of training tasks and their performance modes. To choose the most rational mode of exercises of the series of tasks when teaching girls aged 14 a press headstand and handstand, the first discriminant function can be used with an emphasis on the most informative variables.

Experiment Planning in the Simulation of Industrial Processes

In the analysis of complex industrial processes, it is of great importance to select the most significant factors. Factors are usually ranked on the basis of the researchers’ experience or expert opinions in the field, with mathematical appraisal of their consistency. However, that approach cannot be used in the development of a new process. In that case, experimental methods are used to select the most significant factors. However, this approach is expensive, time-consuming, and sometimes not even feasible. In the present work, a different approach is outlined. Thermodynamic modeling permits numerical experiments. By means of mathematical experiment planning, the influence of more than ten factors on the target function may be taken into account in a single calculation. The particular formulas for the process parameters obtained by this means permit the elimination of the least significant factors without the need for physical experiments. Another important benefit is that this approach permits assessment of the variation in phase and elemental composition of the products and the threshold of practicality of the process in terms of the batch and temperature conditions, with monitoring of the reliability of the results by mathematical means. On that basis, a generalized equation for the monitored process parameter as a function of all the relevant factors may be derived. That is not possible in standard modeling. As an illustration, the proposed approach is used in the development of a production technology for ferroboron using local material. In this case, thermodynamic modeling employs factors selected on the basis of prior calculations. These factors are also used in physical modeling of the process in a high-temperature furnace. The physical experiment confirms the significance of the factors selected. By experiment planning, the number of numerical experiments may be decreased by a factor of 25, and the number of physical experiments by a factor of 125, without loss of predictive accuracy. In the proposed approach, the extraction coefficient may be brought closer to the equilibrium value on the basis of the most significant factors, by comparison of the calculation results with the results of the physical experiments..

Vanadium Electrorefining in NaCl–KCl–VCl2 Melts

Molten salt mixtures can be effectively employed for electrowining and electrorefining of relatively chemically active rare refractory metals having negative reduction potential. One of such metals is vanadium. However quality of the metal produced (impurities content and size of crystals in the deposit) and current efficiency in a standard vanadium electrorefining process does not fully correspond to the requirements. The current work was carried out aiming to determine the optimal conditions of operating industrial vanadium electrolysis baths. The experiments on vanadium electrorefining were carried out in a semi-industrial electrolyser made of stainless steel. Crude vanadium metal was loaded in an anodic basket made of molybdenum. The experiments were performed in dry purified argon atmosphere, and glassy-carbon or nickel crucibles were used to contain the melt. Vanadium-containing melts were prepared by dry chlorination of vanadium metal with subsequent absorption of chlorination products by fused salt mixtures. To stabilize vanadium(II) ions, the molten electrolyte was kept in contact with vanadium for 12–18 hours. Mean oxidation state of vanadium in the melt determined oxidimetrically was always close to two and didn’t depend on vanadium concentration. The method of mathematical planning of experiments was used to determine optimal conditions of electrolysis. Current efficiently was chosen as a response factor. Variable parameters and their intervals were chosen on the basis of the preliminary experiments and the results of kinetic studies. Current density, vanadium concentration and specific quantity of electricity were selected as variables. Temperature had no effect on the current efficiency and increasing temperature only resulted in rising vapor pressure of the melt. Therefore, temperature was not included into variable parameters. Anodic current density was kept essentially constant between 0.1 and 0.15 A/cm2. Such anodic current density allowed maintaining average oxidation state of vanadium ions close to two in the course of the experiments. The 23 full factor experiment was performed and the regression equation was obtained using the experimental results. All variable parameters were significant and the equation obtained was adequate. The influence of the quadratic term was insignificant. The response function was then obtained in the form of a dependence of the cathodic current efficiency on current density, vanadium concentration and specific quantity of electricity passed. The most suitable parameters of vanadium electrorefining were determined using this equation and the experiment under the optimal conditions was carried out, Figure. The total amount of impurities in the refined product was below 0.09 wt. % and the current efficiency equaled to 0.96 g/A∙h. Figure. High-purity electrolytic vanadium Figure 1

Application of mathematical planning in production of filled emulsion rubbers

The applicability of mathematical planning of experiment in the field of chemistry and chemical engineering, in particular in the industrial production of synthetic rubbers, is considered in the article. Possibility of using secondary material resources, which are waste products of light industry, in the production of elastomeric compositions is studied. The method of obtaining a powdered cellulose additive from wastes containing cellulose fiber is described. The best way of introducing the obtained additive into elastomeric compositions based on the emulsion rubber is established. Optimal conditions for obtaining filled emulsion rubber with the help of a powdered cellulose additive were established basing on the mathematical planning of experiment.

Effectiveness of Motor Skills Development in 5th-7th Grade Girls at Different Modes of Physical Exercises

The objective is to determine the influence of the physical exercises modes on effectiveness of motor skills development in 5th-7th grade girls. Materials and methods. The study involved 5th grade girls (n = 28), 6th grade girls (n = 28) and 7th grade girls (n = 24). To solve the tasks set, the study relied on general scientific and special research methods, methods of mathematical experiment-planning.Studying the influence of different variants of the educational process structure, namely: the number of repetitions (x1) and the rest intervals (x2) on acquisition of the technique of physical exercises performance, provided for achieving the objective. A full 22 type factorial experiment was conducted. The 5th-7th graders were divided into training groups according to the experiment plan. In total, there were twelve experimental groups organized, four in each class.Results. The analysis of the regression equations shows that the rest interval between repetitions (x2) has the greatest influence on teaching 5th-7th grade girls physical exercises, with the number of repetitions (x1) being of somewhat less significant influence. The relation between these factors (x1x2) has a considerable weight in teaching to “rope climb in two or three sets” and to do a “pullover mount with a swing of one and a push-off with the other leg”.Conclusions. To increase the effectiveness of teaching 5th-7th grade girls physical exercises, the number of repetitions in throwing exercises should be increased to twelve times, and the rest interval reduced to 60 seconds. In the 7th grade, the number of repetitions should be reduced to six times, and the rest interval – to 60 seconds. The rest intervals in the exercises: “pullover mount with a swing of one and a push-off with the other leg” and “rope climbing in two or three sets”, should be reduced to 60 seconds and the number of repetitions – to six.

THE SUBSTANTIVE FACTORS COMPLEX INFLUENCE ON THE SURFACE LAYERS' INTERNAL TENSIONS IN THE STEEL HARDENED CAR'S PARTS

Досліджено актуальне питання комплексного впливу режимів електролізу на структуру та величину внутрішніх напружень у поверхневих шарах різної товщини насталених автомобільних деталей. Встановлено, що на якість насталених покриттів значною мірою впливають такі вагомі чинники як густина струму, температура та кислотність електроліту. Для визначення комплексного впливу вагомих чинників на внутрішні розтягувальні напруження у поверхневих шарах насталених деталей за різної їх товщини застосовано системний підхід, вихідною передумовою якого є прагнення з максимальною повнотою врахувати початкові та вихідні характеристики об'єкту. На підставі застосування методу планування експерименту отримано регресійні рівняння, які дають змогу оцінити взаємовплив густини струму, кислотності та температури електроліту на внутрішні напруження у поверхневих шарах різної товщини насталених автомобільних деталей. За результатами аналізу регресійних рівнянь й оцінки числових значень та знаків їх коефіцієнтів з'ясовано, що для різної товщини покриття сила й характер впливу чинників є неоднаковими, що дасть змогу вдосконалити технологічні процеси відновлення автомобільних деталей електролітичним нарощуванням.

ВИВЧЕННЯ ВПЛИВУ ДОПОМІЖНИХ РЕЧОВИН НА ФАРМАКО-ТЕХНОЛОГІЧНІ ВЛАСТИВОСТІ ТАБЛЕТОК СУХОГО ПОРОШКУ БІОМАСИ FLAMMULINA VELUTIPES

Мета роботи. Вивчити вплив чотирьох груп допоміжних речовин (наповнювачі, розпушувачі, змащувальні та ковзні, зв’язуючі) на фармако-технологічні властивості таблеток сухого порошку біомаси Flammulina velutipes.Матеріали і методи. Дослідження впливу допоміжних речовин (ДР) на такі показники, як зовнішній вигляд, однорідність маси, стійкість до роздавлювання, стираність та розпадання таблеток проводили відповідно до вимог ДФУ 2 видання. Вивчення чотирьох груп ДР здійснювали за допомогою математичного планування експерименту.Результати й обговорення. На підставі множинних порівнянь рівнів вивчених факторів зроблено висновки про вплив ДР на показники якості таблеток сухого порошку біомаси F. velutipes. При використанні будь- якого із представників груп ДР одержували близькі результати впливу на однорідність маси таблеток. Задовільні результати стираності таблеток одержано у 13 серіях дослідів, з них 5 мали середній показник менше 0,5%. Спресовані таблетки сухого порошку біомаси F. velutipes мали різні показники міцності, лише у 9 серіях дослідів показник був вищим 50 Н. При вивченні впливу ДР на розпадання таблеток виявили 7 незадовільних серій препарату.Висновки. Встановлено вплив чотирьох груп ДР на такі фармако-технологічні характеристики таблеток сухого порошку біомаси F. velutipes, як зовнішній вигляд, однорідність маси, стійкість до роздавлювання та розпадання. Відібрано оптимальні представники досліджуваних груп ДР (цукор білий подрібнений, глина біла, кислота стеаринова, 2 % крохмальний клейстер) для отримання таблеток сухого порошку біомаси F. velutipes методом вологого гранулювання.

Effect of Charge Fractional Composition and the Coke Amount on the Parameters of Manganese Ore Agglomeration

Under laboratory conditions, the method of mathematical planning of experiments was used to study the effect of charge fractional composition (in the range of 2 to 8 mm) and the amount of coke in the charge (in the range of 7 to 13 wt.%) on the agglomeration process characteristics of the “Mamatwan” manganese ore (South Africa). It was found that the main agglomeration parameters vary within the following limits: the initial vacuum under grate – 54...140 mm WC for the charge layer of 350 mm; the maximum temperature – 1365...1440 °С; linear burning speed – 13,4...26,2 mm/min; the charge length of stay at temperatures over 1300 °С (the width of the melting zone) – 2,4...4,8 minutes. Mathematical equations of the combined effect of charge fractional composition and the amount of coke on agglomeration temperature, linear burning speed, width of melting zone (in time), initial vacuum in reactor were calculated. It was found that a major factor in providing the optimum mode of agglomeration is not the amount of coke, but the charge piece size distribution. For example, increasing the charge piece size has an 3,5 times more effective influence on the agglomeration temperature than the amount of coke. For the dust-containing charges the moistening up to 4...6 wt.% H2O is only partially solves the problem of the aerodynamic resistance. Pre-granulation of the dust fraction is needed to improve the gas permeability of the charge.

Modeling of Teaching University Students to Serve a Direct Volleyball Overhand

The objective is to determine the peculiarities of developing motor skills in the first-third-year students.Materials & methods: the participants in the study were male students of the first year (n = 32), second year (n = 32), and third year (n = 32) of training. To achieve the tasks set, the study relied on the following research methods: analysis of scientific literature, pedagogical testing, pedagogical observation and experiment. The study used the methods of mathematical planning of a complete factorial experiment to obtain a mathematical model of training modes.Results: the increase in the number of sets to twelve times, the number of repetitions in each set – to three times, and the rest interval – to 60 seconds positively impact the effectiveness of the first-third-year students’ training. The choice of training modes depends on the number of repetitions in a set for the first-year students; reduction in the rest interval to 60 seconds for the second-year students; the relation between the number of sets and the number of repetitions in a set for the third-year students.Conclusions: The 23-type experiment made it possible to study the multi-factorial structure of training modes of teaching technical elements to the first-third-year students; to specify the optimal relation between the number of sets, the number of repetitions in a set and rest intervals at the stage of teaching to serve a direct volleyball overhand.