scholarly journals Modeling of Aerodynamic Separation of Preliminarily Stratified Grain Mixture in Vertical Pneumatic Separation Duct

2021 ◽  
Vol 11 (10) ◽  
pp. 4383
Author(s):  
Serhii Kharchenko ◽  
Yurii Borshch ◽  
Stepan Kovalyshyn ◽  
Mykhailo Piven ◽  
Magomed Abduev ◽  
...  

The productivity of most grain cleaning machines seems to be directly related to the efficiency of vertical pneumatic separation ducts. Nevertheless, improvement is accompanied by an increase in the load of the vertical duct, the design of which is limited by the width of the grain cleaning machines. This requires an increase in the thickness of the layer of grain mixture that enters the working area of the duct, which significantly worsens the conditions of separation of its components under the action of airflow. Particles of light impurities are unable to separate due to their retention by the grain medium. This reduces the quality of cleaning and requires appropriate scientific and technical solutions. The application of preliminary stratification of the granular mixture while increasing the concentration of light impurities in the top layer of the mixture seems to be a prospective method. The positive effect of the previous stratification on the intensity of redistribution of light impurity particles in the working zone has been theoretically considered and experimentally confirmed. Mathematical models were obtained to determine the trajectory of discussed particles, taking into account the previous stratification of mixtures, and the corresponding dependences were established. The influence of the initial coordination of the introduction of the particles of lightweight impurities, their sizes and densities, and technological and structural parameters of operation of the pneumatic separation duct were taken into account in the studies. The intensification of the process of cleaning grain from lightweight impurities in the working zones of pneumatic separation ducts of grain cleaning machines is theoretically substantiated.

2014 ◽  
Vol 54 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Monika Kováčová ◽  
Miloš Matúš ◽  
Peter Križan ◽  
Juraj Beniak

The quality of a high-grade solid biofuel depends on many factors, which can be divided into three main groups - material, technological and structural. The main focus of this paper is on observing the influence of structural parameters in the biomass densification process. The main goal is to model various options for the geometry of the pressing chamber and the influence of these structural parameters on the quality of the briquettes. We will provide a mathematical description of the whole physical process of densifying a particular material and extruding it through a cylindrical chamber and through a conical chamber. We have used basic mathematical models to represent the pressure process based on the geometry of the chamber. In this paper we try to find the optimized parameters for the geometry of the chamber in order to achieve high briquette quality with minimal energy input. All these mathematical models allow us to optimize the energy input of the process, to control the final quality of the briquettes and to reduce wear to the chamber. The practical results show that reducing the diameter and the length of the chamber, and the angle of the cone, has a strong influence on the compaction process and, consequently, on the quality of the briquettes. The geometric shape of the chamber also has significant influence on its wear. We will try to offer a more precise explanation of the connections between structural parameters, geometrical shapes and the pressing process. The theory described here can help us to understand the whole process and influence every structural parameter in it.


Author(s):  
S. P. Eron’ko ◽  
M. Yu. Tkachev ◽  
E. V. Oshovskaya ◽  
B. I. Starodubtsev ◽  
S. V. Mechik

Effective application of slag-forming mixtures (SFM), being fed into continuous castingg machine (CCM) moulds, depends on their even distribution on the melt surface. Manual feeding of the SFM which is widely usedd does not provide this condition, resulting in the necessity to actualize the work to elaborate systems of SFM mechanized feedingg into moulds of various types CCM. A concept of the designing of a system of SFM feeding into CCM moulds presented with the ratte strictly correspondent to the casting speed and providing formation of an even layer of fine material of given thickness on the whoole surface of liquid steel. The proposed methods of designing of the SFM mechanized feeding systems based on three-dimensional computer simulation with the subsequent verification of the correctness of the adopted technical solutions on field samples. Informattion is presented on the design features of the adjusted facilities intended for continuous supply of finely granulated and powder mixtuures on metal mirror in moulds at the production of high-quality billets, blooms and slabs. Variants of mechanical and pneumo-mechaanical SFM supply elaborated. At the mechanical supply the fine material from the feeding hopper is moved at a adjusted distance bby a rigid horizontally located screw. At the pneumo-mechanical supply the metered doze of the granular mixture is delivered by a sshort vertical screw, the lower part of which is located in the mixing chamber attached from below to the hopper and equipped with ann ejector serving for pneumatic supply of the SFM in a stream of transporting gas. It was proposed to use flexible spiral screws in the ffuture facilities of mechanical SFM feeding. It will enable to eliminate the restrictions stipulated by the lack of free surface for locatiion of the facility in the working zone of the tundish, as well as to decrease significantly the mass of its movable part and to decreaase the necessary power of the carriage moving mechanism driver. The novelty of the proposed technical solutions is protected by thhree patents. The reduction of 10–15% in the consumption of slag-forming mixtures during the transition from manual to mechanizeed feeding confirmed. The resulting economic effect from the implementation of technical development enables to recoup the costs inncurred within 8–10 months.


GYNECOLOGY ◽  
2020 ◽  
Vol 22 (1) ◽  
pp. 14-18 ◽  
Author(s):  
Tatyana Yu. Pestrikova ◽  
Elena A. Yurasova ◽  
Igor V. Yurasov

Relevance. Endometriosis is a common gynecological disease that affects up to 10% of women of reproductive age worldwide and is the main cause of pain and infertility. Endometriosis is a disease, although it has been known for a long time, nevertheless, in many ways it represents terra incognita for modern medicine. Aim. Analysis of literature on the feasibility of long-term and the use of the drug dienogest 2 mg (Vizanne), which has a positive effect on the quality of life of patients with endometriosis. Materials and methods. To write this review, a search was made for domestic and foreign publications in Russian and international search engines (PubMed, eLibrary, etc.) over the past 13 years. The review included articles from peer-reviewed literature. Results. The review presents data on the difficulties of verifying the diagnosis of endometriosis due to a combination of this pathology with pain, infertility, abnormal uterine bleeding. The pathogenesis of the origin of endometriosis-associated pain is presented. The efficacy of the use of the drug dienogest (Vizanne), which has a powerful antiproliferative effect that reduces the main symptoms of endometriosis (pain, bleeding), is substantiated. The expediency of long-term and safe use of the drug dienogest (Vizanne), which has a positive effect on the quality of life of patients with endometriosis, has been proved. Conclusions. Numerous scientific publications confirm the feasibility of prolonged use of the drug dienogest (Vizanne), to achieve remission during endometriosis.


Author(s):  
Bambang Ismanto ◽  
Lasmono Tri Sunaryanto ◽  
Gatot Sasongko

Entrepreneurship of principals in the educational environment to enhance students' creative behavior and achievements through innovation and the development of learning methods is very important. The principal has the task of managing resources and taking advantage of opportunities in improving the quality of education. This study aims to discuss the significant variables in increasing entrepreneurship principals. The study uses a quantitative approach with path analysis. The research sample was 334 Principals of Kindergarten, Elementary, Middle and High Schools in Central Java Province. Data collection was carried out by studying documentation and questionnaires. Data analysis was performed by path analysis with the AMOS program. The results showed that the rank and tenure as a teacher had a positive and significant effect on the tenure as a principal. While the use of social media has a significant negative effect. Of the various independent variables observed, only the existence of opportunities that had a significant positive effect on the ability of innovation of the principal. While the variables that significantly influence the development of learning methods are the ability of innovation and the presence of opportunities. The development of learning methods and the existence of opportunities will subsequently have a positive effect on improving student achievement, as the ultimate goal of developing entrepreneurship by the principal. Pathways to improve the entrepreneurship of principals are the existence of opportunities, tenure as principal, innovation and the development of instructional media. Keywords: Entrepreneurship, Principal, Inovation. Creativity,


2020 ◽  
Vol 3 (2) ◽  
pp. 215-221
Author(s):  
Nelly Budiyarti

Abstrak: Kualitas pembelajaran dan minat belajar memungkinkan hasil belajar mahasiswa meningkat. Sehingga diharapkan kualitas pembelajaran dan minat belajar mahasiswa tinggi untuk mencapai hasil belajar yang tinggi pula. Penelitian ini bertujuan untuk melihat bahwa kualitas pembelajaran dan minat belajar mahasiswa berpengaruh terhadap peningkatan hasil belajar mahasiswa Akuntansi pada mata kuliah Matematika Ekonomi. Penelitian ini merupakan penelitian survei dengan meggunakan teknik analisis jalur (path analysis), dimana terdapat dua variabel eksogen dan satu variabel endogen.  Variabel eksogen berupa kualitas pembelajaran dan minat belajar, sedangkan variabel endogen berupa hasil belajar. Hasil penelitian ini adalah Kualitas Pembelajaran berpengaruh langsung positif terhadap Hasil Belajar, Minat Belajar berpengaruh langsung positif terhadap Hasil Belajar, dan Kualitas Pembelajaran berpengaruh langsung positif terhadap Minat Belajar Mahasiswa. Abstract:  The quality of learning and interest in learning allows student learning outcomes to increase. It is hoped that the quality of learning and student interest in learning will be high to achieve high learning outcomes. This study aims to see that the quality of learning and student interest in learning has an effect on improving student learning outcomes in Accounting Economics Mathematics courses. This research is a survey research using path analysis technique, where there are two exogenous variables and one endogenous variable. Exogenous variables are learning quality and learning interest, while endogenous variables are learning outcomes. The results of this study are Learning Quality has a direct positive effect on Learning Outcomes, Learning Interest has a direct positive effect on Learning Outcomes, and Learning Quality has a direct positive effect on Student Learning Interest.


2018 ◽  
Vol 3 (2) ◽  
pp. 161
Author(s):  
Satria Tri Nanda

<p><em>This research aims to identify the factors influencing the audit quality of auditors at Inspektorat Provinsi Riau. The population in this research were auditor, examiner, assistant examiner, and P2UPD (Pengawas Penyelenggara Urusan Pemerintah di Daerah) in charge at the Inspectorate in Riau Province and all Inspectorates in Districts and Cities in Riau Province. A total of 290 set of questionnaire were sent and a number of 184 of questionnaires were processed. Using regression analysis conducted by SPSS, the hypotheses testing analysis results show that experience, responsiveness, professional care, executive involvement</em><em>t, planning</em><em> and auditability have significant and positive effect on audit quality. These results indicate that the higher the levels of experience, responsiveness, professional care, executive involvement and auditability of Inspectorate officials, the better the quality of audit performed by the Inspectorate Officials of Riau Province.</em></p>


2012 ◽  
Vol 30 (No. 5) ◽  
pp. 474-482 ◽  
Author(s):  
L. Siříšťová ◽  
Š. Přinosilová ◽  
K. Riddellová ◽  
J. Hajšlová ◽  
K. Melzoch

The production technology of high-quality vodka used in Russia involves filtration through activated charcoal. To approach the quality of renowned Russian vodka, one prominent Czech spirit-producing company installed on its production premises a filtration device including a charcoal column, and launched test runs during which different filtration conditions were tested. Samples collected during the test runs were analysed by GC-FID and GC-MS with the aim to compare their composition; sensory analysis was an integral part of the evaluation. The results documented a positive effect of charcoal filtration on the quality of produced vodka, which was not reduced when higher flow rates were applied. &nbsp;


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alicja Kowalczyk ◽  
Elżbieta Gałęska ◽  
Ewa Czerniawska-Piątkowska ◽  
Anna Szul ◽  
Leszek Hebda

AbstractThe aim of this study was to analyze the relationship between the concentration of hormones in the seminal plasma, the bull maintenance system in the insemination station, and the regularity of sperm donation and the response to the phantom (libido level). An additional goal was to determine whether there is a relationship between the hormonal profile in the blood, the sperm plasma, the oxidative and antioxidant profile in the blood of bulls and the biometry of their testicles and scrotum, as well as the quality of their sperm in both different seasons and intensities of reproductive use. For the study, 220 healthy and sexually mature Polish Holstein–Friesian bulls were used. They all had normal libido and were fed equally. The animals were grouped according to the scheme: young (16–20 month/n = 60) and old (26–30 month/n = 60) including: individually housed (n = 30) and group housed (n = 30) young, old individually housed (n = 30) and group housed (n = 30) (n total animals = 120); young animals donating semen once a week (every Thursday) (n = 25) and sporadically (once every two months on a random day of the week) (n = 25), old animals donating semen once a week (every Thursday) (n = 25 ) and sporadic donors (once every two months on a random day of the week) (n = 25) (n total animals = 100). When analyzing the results of this study, it should be stated that regular use has a positive effect on the secretion of sex hormones in bulls. Higher levels of testosterone and lower levels of estradiol and prostaglandins resulted in higher sexual performance, expressed by a stronger response to the phantom. The differences in favor of regular use were independent of the bull's age. The results of our research illustrate that the quality of semen and its freezing potential may depend on the season and frequency of its collection, as well as on the age of the males.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Xiang Yin ◽  
Zhiyi Meng ◽  
Xin Yi ◽  
Yong Wang ◽  
Xia Hua

AbstractChina has made great efforts to alleviate poverty in rural ethnic minority areas and targeted achieving the poverty-alleviation task by the end of 2020. Aba, Ganzi, and Liangshan, three of the poorest ethnic prefectures in Sichuan Province, Southwest China, have all implemented “Internet+” tactics since 2013, which have had the positive effect of increasing family revenues by improving communication infrastructure and encouraging the large-scale use of e-commerce. This paper aims to comprehensively investigate whether “Internet+” tactics play a key role in poverty alleviation in Sichuan’s rural ethnic minority areas and to propose further measures to enhance the efficiency of e-commerce practice. To this end, we conduct an analysis using the framework of classic growth theory and use panel data from 2000 to 2018 to examine the relationship between Communication Infrastructure Investment (CII) and a set of poverty-alleviation indicators, including local GDP growth rate (LGGR), local government revenue (LGR), and per-capita income of residents (PCIR). The results indicate that strengthening CII improves the PCIR and local economic growth, playing a key role in poverty alleviation. However, the stimulation of CII on LGGR and LGR wanes as time passes. More financial and technical actions will be needed to improve the efficiency and quality of current strategies for sustainable development in those areas.


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