bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of the oil spill at the la pampilla refinery on the economy of the inhabitants of the coastal areas of the lima and callao regions
Authors: Porras Eduardo Villalobos
Published: November 2022

This article makes a brief analysis of what happened with the oil spill at the La Pampilla refinery, located in the district of Ventanilla, and its impacts on the economy of the people who live from tourism, artisanal fishing and local gastronomy in some coastal districts of the regions of Lima and Callao, belonging to Peru. Based on this review, some proposals for action are proposed, linked to the reactivation of the local economy of these populations that are interrelated with the coastal marine ecosystem, in the short, medium and long term in the regions of Lima and Callao.
Determinants of survival time among HIV-infected patients receiving care at antiretroviral therapy (art) clinic of a public hospital, Ethiopia
Authors: Gebremichael Shewayiref Geremew
Published: November 2022

Introduction: Even if there are different barriers to HIV testing in developing countries, timely access to care and early diagnosis improves the clinical course of the disease, reduces the transmission rates, and prolongs the survival time of patients. Objectives: This study aimed to investigate the potential predictors of survival time in a cohort of HIV-infected patients on ART using the parametric survival model perspective. Data and Methods: A hospital-based retrospective cohort charts-review study design was conducted on 647 patients from a public referral hospital in North-Central Ethiopia from July 2012 to January 2017. Log-rank and Wilcoxon tests, and an Accelerated Failure time (AFT) parametric statistical model were used. Results: A mean of 22.13months (SD=13.16) and a median of 21.47months (IQR: 11.55-33.30) were found. The median age, baselineCD4 count, and BMI of patients at baseline were 30years (IQR: 25-38years), 247cells/µl (IQR: 120-375cells/µl) and 19.75kg/m2 (IQR: 17.5-22kg/m2); respectively. At baseline, the patients CD4 count values ranged from 11 to 1764 (mean=289, SD= 233). The study revealed that 192(29.68%) events occurred, while 455(70.32%) were censored. The Gamma model was selected as the best-fit parametric model for the data. The estimated shape parameter of the fitted Gamma model is 1.9983 with 95%CI (1.3426, 2.9741) indicating that significantly determined as the survival time increases over time. Conclusion: The fitted AFT parametric model (Gamma distribution), the factors such as: higher BMI, higher current CD4 count, being married, starting on AZT-3TC-EFV regimen class significantly increased the survival time of HIV-positive patients attending ART treatment, while; baseline CD4 count and ambulatory functional status reduces the survival time of HIV patients. Moreover, using ART treatment significantly improves the survival time of patients.
Cross-sectional study on knowledge, attitude and practice about diabetes mellitus among diabetic patients with type II; Asmara, Eritrea
Authors: Teages Adgoy Elias , Ghebretinsae Awet , Solomon Michael , Girmay Kebire , Fissehaye Danait , Andemariam Zekarias
Published: November 2022

Introduction: Diabetes mellitus (DM) type II is one of the most common chronic disease conditions in human history and now it is emerging as an epidemic of the 21st century. Besides the global epidemicity, DM is increasing and becoming a priority disease especially in countries undergoing socio-economic transformation. It has been recommended that self-care, Knowledge, Attitude and Practice (KAP) about the disease is the cornerstone for proper management. Therefore, this study was conducted to evaluate the levels of Knowledge, Attitude, and practice of patients with Diabetes mellitus Type II in Asmara, Eritrea. Methods: Cross-sectional study on Knowledge, Attitude and Practices of diabetic patients was conducted starting from May 1st to July 1st, 2018, at Halibet and Haz-Haz hospital diabetic clinics, Asmara. The study participants included were from two hospitals based and selected by systematic random sampling. Data collection was done using a structured questionnaire and data were analyzed using SPSS version 25 software. Statistical analyses included correlation tests, ANOVA and t-test. Results: Three hundred seventy adult diabetic patients, 45.9% males and 54.1% females were enrolled participated in the study. The majority (97%) was greater than 40 years of age and 54% had a family history of Type II diabetes. The levels of diabetic patients’ knowledge attitude, and practice were 51.9%, 40.9 % and 42.6 %, respectively. There was a signiﬁcant correlation between age, sex (male), educational level, family history, duration of diabetes mellitus and use of oral hypoglycemic agents in combination to Insulin with KAP level. Conclusions: The results of this study showed that KAP regarding diabetes mellitus to be low. The presences of complications were found to be significantly associated with attitude. The study results were also found to have a significant association and positive correlation with duration of DM. Therefore, the study results recommend continuous education about DM and its complications mainly to a newly diagnosed patient’s in order to create early awareness and good knowledge.
Respiratory symptoms, lung function and dust exposure among workers in grain milling industries in Dar Es Salaam, Tanzania
Authors: Ulanga Anifa J , Mamuya Simon H , Sakwari Gloria , Mlimbila Jane
Published: November 2022

Background: Workers in grain milling industries are exposed to grain dust released during milling processes. Exposure to grain dust is associated to various respiratory symptoms such as phlegm, breathlessness, and cough and wheezing and it also leads reduced lung function. This study aimed at determining grain dust exposure levels and the prevalence of respiratory symptoms and Lung function among grain mill workers Dar es Salaam. Methodology: A descriptive cross sectional study was used to collect information on Respiratory symptoms among 264 grain mill workers and 100 controls by using a Questionnaire. Lung function tests were carried out on 180 grain mill workers and 68 controls by using an easy one spirometer while Personal dust exposure was measured on 30 grain mill workers and 5 controls by using PVC filters of 8µm pore size on two piece filter cassette mounted on Sidekick Casella (SKC) pump. P value of less than 0.05 was used as criteria for significant association. Ethical clearance was approved by the ethical clearance board of Muhimbili University of Health and Allied Sciences research and publication Committee. Results: Grain workers were exposed to higher levels of total dust with GM 12.15mg/m3 (GSD 1.53) than the control GM mg/m3 (GSD). Most of the workers in grain milling industries 66.7% were exposed to dust concentrations above the OEL (10mg/m3). The Prevalence of respiratory symptoms was higher among grain mill workers, (51.1%, 41.3%, 33.7%, 17%and 9.8% for cough, phlegm, breathlessness, tightness and wheezing respectively than in controls (28%, 19%, 21%, 8% and 5% for cough, phlegm, breathlessness, tightness and wheezing respectively. 26% and 21% of Grain workers were exposed to higher levels of total dust with GM 12.15 mg/m3(GSD 1.53) than control GM 0.17 mg/m3 (GSD 0.35). Conclusion: Exposure to grain dust in a working environment causes the increase in work related respiratory symptoms and reduced lung function. This study recommends the use of control measures to decrease dust exposure level among mill workers, also periodic medical examination should be conducted to assess workers health. A cohort study nationwide might give yield a more generalized outcome.
Juvenile delinquents and sports
Authors: Mijanovic Mihajlo
Published: November 2022

A sample of 80 juvenile delinquents was examined to determine the motives that decide juvenile delinquents decide to play sports. For this purpose, a survey of eleven questions was used. After the conducted research and extensive statistical analysis, three factors were extracted, the first of which is particularly relevant. It can be reliably concluded that juvenile delinquents play sports in order to consume alcohol after and before training, smoke, take opiates, miss school and be out of parental control. The second and third factors are positive, but significantly weaker than the first. The structure of positive factors consists of variables: I play sports to travel, to earn money, to live a healthy lifestyle. To be with a girl who also plays sports. The first factor contributes 42%, the second 17% and the third 16% to the explanation of the problem.
Physical activity in women with depression in the Spanish national health survey: a mediation analysis
Authors: Villamisar Domingo García , Martínez Marta García , John Dattilo
Published: November 2022

Background: Promotion of physical activity (PA) is an important public health goal to reduce depression in women. Although several studies have reported an indirect relationship between physical activity and severity of depression in women across cultures and age groups, other studies have failed to establish this relationship. In this study we aim to analyse whether certain clinical and demographic variables can explain this discrepancy. Methods: Cross-sectional study with 1096 women aged 15 to 69 years who participated in the National Health Survey in Spain 2017. The chi-square test was used for qualitative variables and a logistic regression was used to determine association between PA and depression with sociodemographic characteristics. To assess possible mediation of each clinical and health variable in the association between depression and physical activity, we used the KHB command in Stata. Results: Both the crude model and models adjusted for clinical and socio-demographic variables indicated a positive association between low PA and depression. The KHB decomposition indicates that 62.21% of the association between low physical activity and depression is associated with mediational variables. Self-perception of health and the polypharmacy were the primary contributors to the mediation. Conclusion: This study supports the conclusion that depression is related to lower levels of physical activity in women. Self-perception of health and polypharmacy mediate this relationship. These results have implications for professionals who are developing interventions aimed at increasing physical activity in women experiencing depression.
Hot weather in Qatar can affect the European footballers at FIFA World Cup 2022
Authors: Conley Lorren Kevin , Johnson Jack , Miller Nick
Published: November 2022

This study is the relationship between the climatic conditions predicted for the 2022 FIFA World Cup in Qatar and the capacity for repeated maximum effort of football players. The 2022 World Cup begins in November with 32 countries heading to Qatar to compete for football’s biggest prize. But the real problem is most of the players from European countries and the biggest question is if they can withstand the humidity.
Traumatic elbow bursitis after professional MMA bouts: a case series
Authors: K Sethi Nitin
Published: November 2022

Professional mixed martial art (MMA) is a popular combat sport with a high incidence of orthopedic injuries. Traumatic elbow (olecranon) bursitis (TOB) while a common sport injury has not been well reported in combat sports medical literature. In this case series 4 MMA combatants with TOB are described. The mechanism of injury, clinical presentation and management cage side is discussed with the goal of improving care coordination between ringside and orthopedic physicians to help improve outcomes.
Tatwir Wahdah Taklim Al-Lughah Al-Arabiyyah Elekturuniyyah Li Tholabah As-Shaf As-Tsamin Fi Al-Mahad Al-Kautsar Muhammadiyyah Sarilamak
Authors: Hasti Beni , Harmonedi Harmonedi
Published: November 2022

One of the efforts that teachers can do to attract students to learn, one of which is by designing interesting learning media. Based on observations and interviews conducted in the eighth grade at Islamic boarding school Al-Kautsar, it was found that there was still a lack of interest in student learning so that during the learning took place students did not pay attention to the teacher, the teaching materials used were only glued to existing books, and the teacher's lack of creativity in designing learning media that was able to attract students to learn. Based on this, researchers designed a learning media in the form of an electronic module in learning Arabic. The purpose of this study is to produce Arabic learning media in the form of valid, practical and effective electronic modules so that it can help students in understanding Arabic material in the learning process. The approach used in this study is a qualitative approach to research and development methods in the ADDIE model, which consists of analysis, design, development, implementation and evaluation. The results showed that: 1) the results of the validity of learning media using electronic modules in Arabic language learning obtained were 86.8% with very valid categories, 2) the results of the practicality of learning media using electronic modules in Arabic language learning obtained from the results of the student response questionnaire, namely 94% while the results of the teacher response questionnaire were 97.5% with a very practical category, and the increase in pretest and posttest scores was analyzed using the N-gain test, which was 0.73 with a high category. With this, it can be concluded that the learning media using electronic modules in Arabic language learning are designed to be valid, practical, and effective.
Two grammatical categories for please in Mandarin imperative clauses
Authors: Jheng Wei-Cherng Sam
Published: November 2022

This paper develops a syntax-pragmatics interface analysis of imperative clauses overtly marked by two grammatical categories of qing ‘please’ in Mandarin and refines the division of labor among directive force, clause typing and deontic modality jointly computing the interpretative properties of qing imperatives. We present a cluster of properties to differentiate between the two categories of qing and observe that qing1 denotes obligation imposed on the addressee by the speaker, while qing2 denotes permission with which the addressee is allowed to perform an action or make true a state of affairs according to a set of norms. It is argued that qing1 is an imperative mood head, while qing2 is an imperative adverb, but both are endowed with a similar internal composition and extent of the phrasal hierarchies of the CP periphery, and their disparate imperative properties can be ascribed to the addressee-oriented and subject-oriented deontic modality (Tsai & Portner 2008). Following Haegeman & Hill's (2013) version of the Speech Act Phrase, we claim that a speech act layer externally merges to the topmost position of ForceP to drive the syntax-pragmatics interface computation of the speaker-addressee relation and to mediate the imperative mood and clause typing represented in the CP layer.
Muhammadiyah’s Response to Covid-19 in Indonesia: Faith-Based Commitment
Authors: Qodir Zuly , Jubba Hasse , Loilatu Mohammad Jafar
Published: November 2022

As one of the most prominent Islamic organisations in Indonesia, Muhammadiyah has, since its establishment, contributed substantially to resolving various issues confronted by the Indonesian government and society. The emergence of the COVID-19 Pandemic is also a concern to Muhammadiyah. It may contribute to assisting the government’s efforts and relieving some of the burden bore by the people. The current article aims to provide an analysis of Muhammadiyah’s movement in Indonesia and its handling of the COVID-19 Pandemic by using a faith-based commitment approach in the da’wah Muhammadiyah on Education, health, and caring poverty in the jargon da’wah Amar ma’ruf nahi munkar/effort and supporting virtues and stopping the damaging. Through this approach, it is found that Muhammadiyah has contributed significantly in various fields, particularly health, necessities, education, and preventive measures, regardless of one’s background of religion, ethnicity, and political affiliation. All the assistance that Muhammadiyah had given was based on a faith-based commitment that Muhammadiyah is a socio-religious organisation that has decided to take the path of socio-humanitarian da’wah as stipulated by Muhammadiyah’s founding mandate. The data from Muhammadiyah COVID-19 Command Centre, Indonesian Governance and the Media from March 13, 2020, to January 2021 analysis with in Faith Base Organisation Perspective.
EVALUATION AND COMPARISON OF THE ANTIMICROBIAL AND CYTOTOXIC ACTIVITIES OF SOME AMINO ACID METHYL ESTERS
Authors: KARACA Tuğçe Deniz , BALCI Hüseyin , AYSAN Arzu
Published: November 2022

In this study, the antibacterial and cytotoxic activities of some amino acid methyl esters (L-methionine, L-phenylalanine, L-histidine, L-lysine, L-tryptophan, and L-tyrosine) were investigated. The effect of amino acid methyl ester compounds on antibacterial performance was determinated against Gram-negative and Gram-positive bacteria. The effect of amino acid esters on cell viability was investigated against cancerous and non-cancerous cell lines using the MTS assay. The results showed the substances had low antimicrobial effect on both Gram-negative and Gram-positive bacteria. In addition, it was found that the studied substances did not have a toxic effect on cell growth in non-cancerous cells. For this reason, it is thought that the results obtained will contribute to research on new synthesizable compounds based on amino acid esters and studies on drug development.
Оптимізація режиму роботи холодильної машини, що працює на зеотропній суміші холодильних агентів
Authors: Кравченко М.Б. , Кокул С.В.
Published: November 2022

Кріорефрижератори Джоуля-Томсона, що працюють на сумішевих робочих тілах, мають значні переваги у порівнянні з охолоджувачами, які використовують чисті холодильні агенти. При оптимізації складу зеотропних сумішей холодильних агентів необхідно враховувати особливості роботи компресорів об'ємної дії. Відомо, що коефіцієнт подавання поршневого компресора суттєво залежить від ступеню стиснення та тиску нагнітання компресора. Тому проводити оптимізацію складу зеотропних сумішей холодильних агентів при фіксованій молярній витраті суміші з практичної точки зору є недоцільним. В статті описаний метод оптимізація режиму роботи холодильної машини, що працює на п’ятикомпонентній зеотропній суміші холодильних агентів. В якості цільової функції обрана максимальна холодопродуктивність установки, яка побудована на базі герметичного компресора TAG 2513Z, при температурі об’єкту охолодження 120 К. Метою дослідження є створення відносно простої математичної моделі такого компресора, яка повинна пов’язати тиски на всмоктуванні та нагнітанні з коефіцієнтом об’ємного подавання компресора. При оптимізації варіювалися такі параметри: тиски нагнітання і всмоктування компресора, склад п’ятикомпонентної робочої суміші, а також температура перед дросельним вентилем і температура на вході в фазовий сепаратор. В результаті обробки результатів чисельного експерименту, був отриманий аналітичний вираз, який наближено описує роботу холодильної установки залежно від восьми параметрів, що варіювалися. Це дозволило знайти оптимальний режим роботи холодильної машини, при якому досягається максимум холодопродуктивності. При опти­мальному режимі роботи холодильної установки тиск всмоктування дорівнює 2,4 бар, тиск нагнітання – 17,3 бар. За оптимального складу робочої речовини досягається максимальна холодо­продуктивність 54,7 Вт
Оцінка термодинамічної ефективності абсорбційних водоаміачних термотрансформаторів на основі аналізу ексергетичних втрат в їх елементах
Authors: Біленко Н.О. , Тітлов О.С. , Нікітін Д.М.
Published: November 2022

Екологічна ситуація змушує розробників холодильної техніки переглянути ставлення до абсорбційних холодильних приборів, які комплектуються абсорбційними водоаміачними термотрансформаторами (АВТ) та можуть розглядатися як один із альтернативних варіантів переходу на екологічно безпечні холодоагенти. Робоче тіло АВТ складається із природніх компонентів – водоаміачного розчину (ВАР) з додаванням інертного газу (водню, гелію або їх суміші) та є абсолютно екологічно безпечним – має нульові значення озонознищуючого потенціалу та потенціалу «парникового» ефекту. Представлено оригінальну методику ексергетичного аналізу АВТ. Показано, що основні ексергетичні втрати у циклі АВТ припадають на генератор у процесах генерації пари та транспортування рідкої фази (при роботі на електроенергії – до 80 %, з пальними пристроями – до 60 %). Для їх зменшення необхідно провести оптимізаційні розрахунки генераторного вузла АВТ, ексергетичні втрати у якому, як мінімум, на порядок вищі, ніж у будь-якому іншому елементі АВТ. Результати енергетичного аналізу режимних параметрів серійних та дослідних моделей АВТ дозволили сформулювати низку рекомендацій для виробників енергозберігаючих агрегатів. Показано, що склад інертного газу впливає на ефективність циклу. Заміна водню гелієм призводить лише до зростання кількості циркулюючого газу в 2 рази, що ускладнює роботу контуру природної циркуляції АВТ. Варіантом подальшого енергетичного вдосконалення АВТ перспективно розглянути бінарну суміш трифторетанол (TFE) – тетраетиленгліколь диметиловий ефір (TEGDME), яка може бути більш вигідною для циклів поглинання при високих температурах, ніж класичні робочі системи, такі як H2O-LiBr та NH3-H2O. Ця система не піддається корозії, повністю змішується в широкому діапазоні температур, термостійка до 250 °C і має низький робочий тиск. У частині підвищення енергетичної ефективності генераторного вузла одним з перспективних напрямків може бути заміна традиційного сталевого матеріалу корпусу АВТ на алюмінієві сплави, які показали не тільки високі теплопередавальні характеристики, але і корозійну стійкість при взаємодії в водоаміачної сумішшю
CONVOLUTIONAL NEURAL NETWORKS FOR PROBLEMS IN TRANSPORT PHENOMENA: A THEORETICAL MINIMUM
Authors: Bhasin Arjun , Mistry Aashutosh
Published: November 2022

Convolutional neural network (CNN), a deep learning algorithm, has gained popularity in technological applications that rely on interpreting images (typically, an image is a 2D field of pixels). Transport phenomena is the science of studying different fields representing mass, momentum, or heat transfer. Some of the common fields are species concentration, fluid velocity, pressure, and temperature. Each of these fields can be expressed as an image(s). Consequently, CNNs can be leveraged to solve specific scientific problems in transport phenomena. Herein, we show that such problems can be grouped into three basic categories: (a) mapping a field to a descriptor (b) mapping a field to another field, and (c) mapping a descriptor to a field. After reviewing the representative transport phenomena literature for each of these categories, we illustrate the necessary steps for constructing appropriate CNN solutions using sessile liquid drops as an exemplar problem. If sufficient training data is available, CNNs can considerably speed up the solution of the corresponding problems. The present discussion is meant to be minimalistic such that readers can easily identify the transport phenomena problems where CNNs can be useful as well as construct and/or assess such solutions.
Biomechanical Analysis of Two-Level Novel Cage-Type Implant for Anterior Cervical Discectomy and Fusion: A Finite Element Analysis
Authors: Kumar Ram , Kumar Amit
Published: November 2022

One of the standard treatments for spinal diseases is anterior cervical discectomy and fusion (ACDF). ACDF is a secure and successful operation that prevents patients to improve their pain and function. The mechanical goal of the ACDF is to prevent motion between adjoining vertebrae by a novel cage-screw implant. The objective of this study is to analyze the biomechanical flexibility in terms of the range of motion (ROM) of two-level ACDF fixation using the finite element method (FEM). A CT scan-based FEM model of the cervical spine (C2-C7) is used and two-level cage is implanted at C4-C6 segments. A 50-N compressive force and 1-Nm moment are applied on C2 vertebrae and C7 is fixed in all directions. The ROM at two-level fixation (C4-C5-C6) is reduced by 55 to 88% compared with intact spine during all physiological movement. The ROM slightly increase (3-9%) at the adjacent segment. The maximum von Mises stress variations are 25-65 MPa during flexion-extension, lateral bending, and axial rotations under given loading. The maximum von Mises stress found in cage and screw is below the yield stress during all physiological movement.
The representation of sC-clusters: A Strict CV analysis
Authors: Polgárdi Krisztina
Published: November 2022

sC-clusters have always posed a challenge for theories of phonological representation because they behave like coda-onset clusters, but they can also occur word-initially (where their behaviour typically differs from that of branching onsets comprising an obstruent followed by a sonorant). [s] in such initial clusters has been analysed as an appendix, as a coda, or as part of a complex segment. Out of these possibilities, the coda analysis (where initial [s] is assumed to be preceded by an empty nucleus) is shown to account for the data in the most satisfactory way. However, it faces the problem of how to ensure that this empty nucleus remains silent (called Magic Licensing). Instead, I propose a Strict CV representation of initial sC-clusters, where the melody of [s] is shared by a neighbouring V position, by a language specific choice: in Italian and Portuguese [s] occupies the preceding V position, while in English the following one. As the initial nucleus does not remain empty in this analysis, no special licensing is necessary. I also show that not only is the branching representation of [s] identical to that of syllabic sonorants in this model, their distribution is also parallel. In English, syllabic sonorants branch on the left, while syllabic [s] branches on the right, and the differences in their behaviour follow directly from the difference in the direction of branching. Finally, the marked structure of syllabic consonants is only permitted if without their branching the representation is ill-formed. This means that they must always be flanked by a consonant at least on one side.
Coatings from high-entropy alloys: State and prospects
Authors: Gromov V. E. , Konovalov S. V. , Peregudov O. A. , Efimov M. O. , Shlyarova Yu. A.
Published: November 2022

The authors made a brief review of recent publications by foreign and domestic researchers on the structure, phase composition, and properties of films and coatings of five-component high-entropy alloys (HEA) on various substrates and modification of the HEA surface by various types of processing. The main methods of applying films and coatings are considered: magnetron sputtering, thermal sputtering, laser sputtering, and electrodeposition. Particular attention is paid to the deposition of coatings on stainless steels and titanium alloys. The positive change in the tribological, strength properties, and corrosion resistance of film coatings in a wide temperature range is analyzed and possible causes of the observed effects are discussed. The role of solid solution strengthening, formation of fine-grained structure, and the formation of oxide layers enriched with one of the HEA components were taken into account. The authors identified new methods for applying coatings from HEA and subsequent processing. Using Nb and Ti doping as an example, their role in increasing microhardness, wear resistance, and reducing the friction coefficient in coatings were revealed. Electrolytic polishing, electroerosive machining, mechanical polishing and their combination are considered among the methods of HEA surface treatment. A number of works propose a method of powder borating to increase the surface strength and wear resistance of HEAs. The paper considers analysis of works on electron-beam processing as one of the promising and high efficient methods of HEA surface hardening.
Electroplastic effect at tension in TRIP steel
Authors: Stolyarov V. V.
Published: November 2022

The paper presents the results of a study of electroplastic effect in metastable high-alloyed austenitic-martensitic steel in strip form with the thickness of 0.3 mm during plastic deformation with current of different modes and regimes. Choice of the research material is due to manifestation of the TRIP effect in it, caused by martensitic transformation during deformation. The ratio of volume fractions of austenite and martensite in the steel before deformation was 50:50. Deformation behavior of the steel was studied by stress-strain curves and mechanical properties at room temperature in static tension with current by short single pulses of large density, as well as multipulse current with frequency of 1000 Hz and direct current. Microstructure in the initial, before tension, state was investigated by optical and transmission microscopy. It consists of large equiaxed grains of austenite and twinned martensite up to 80 µm in size. Phase composition of the steel before and after tension with and without current was studied by X-ray diffraction. Tensile deformation without current promotes martensitic transformation and increases the volume fraction of martensite from 50 to 82 %. The introduction of single current pulses does not influence the TRIP effect, causes power surges and confirms the occurrence of electroplastic effect. Current mode has a strong influence on manifestation of the TRIP effect, suppressing it at multipulse and direct current and causing a sharp decrease in tensile strength, yield stress, and elongation to failure. Tension with current stabilizes the austenite and reduces content of the formed martensite up to 72 % in multi-pulse mode and up to 50 % when using direct current.
Metal degassing in vacuum-chamber of circulating vacuum degasser of JSC EVRAZ NTMK
Authors: Metelkin A. A. , Sheshukov O. Yu. , Tkachev A. S. , Kovyazin I. V. , Chiglintsev A. V. , Shevchenko O. I.
Published: November 2022

For smelting of high-quality metal for transport purposes, it is necessary to limit the content of harmful impurities in it, including dissolved gases. For example, hydrogen content in the finished product should not exceed more than 2 ppm. In order to obtain low residual hydrogen content in steel in the converter shop of JSC EVRAZ NTMK, the transport metal is processed at circulating vacuuming plants. Circulating vacuum degasser is the last stage of steel processing before casting on continuous casting machine, so it is important to study and improve the technological processes in it. To investigate the physico-chemical processes occurring in this metallurgical unit, a hydrodynamic model of the system circulating vacuum degasser – steel ladle was created. Based on theoretical calculations and experiments conducted on a physical model, the main dependencies between the structural and technological parameters of the metallurgical unit were determined. The resulting equation makes it possible to determine the rate of metal circulation in vacuum chamber depending on gas flow rate supplied to inlet snorkel and its inner diameter at circulating vacuuming plants designed for metal processing in steel ladles with a capacity of 140 – 180 tons. Theoretical calculations were confirmed by practical smelting in a steelmaking unit. It is shown that during the wear of lining of the inlet snorkel vacuum chamber, in order to obtain stable residual hydrogen content, it is necessary to make changes in the technological process of vacuuming. Additionally, rational technological parameters of steel processing at the circulating vacuuming plant were determined on the basis of theoretical calculations.
Numerical studies of heat transfer parameters during injection feeding of powders into the rail steel melt in ladle-furnace
Authors: Protopopov E. V. , Dumova L. V. , Nozdrin I. V. , Chernysheva N. A.
Published: November 2022

Technological features of powdered reagents injection into the melt using a submersible tuyere were investigated for the research and development of the main provisions of rail steel out–of-furnace treatment in a ladle-furnace. Authors analyzed the characteristics of influence of a directed heat flow through the tuyere conditional separation wall from metal to two-phase gas-powder flow under purging conditions. Using numerical methods, were determined the parameters of influence of the submersible tuyere surface temperature on characteristics of the transporting gas, concentration of the powder and its density, and on characteristics of the gas-powder flow, including the aerodynamic drag coefficient, pressure of the transporting gas, difference in phase velocities, equivalent diameter, and particle shape coefficient. The obtained experimental results show that at the same flow rate of the transporting gas, more significant heat flows, ensuring stable operation of the blowing device, are created by using a lighter gas (nitrogen), while the diameter of powdered particles does not affect the amount of heat transferred from the tuyere wall to the transporting gas. It was established that when using submersible tuyeres and heating the gas–powder flow to a temperature of 500 – 600 °C, the strength of the interfacial interaction changes by 2 to 10 times depending on the particle shape coefficient, concentration of the injected powder, pressure of the transporting gas, difference in phase velocities and density of the powder.
Energy efficiency of a cone crusher with stops
Authors: Sakharov D. F. , Vitushkin A. V.
Published: November 2022

Metallurgical, construction and mining industries are based on the process of grinding various materials. The main method of primary preparation of raw materials is crushing of the extracted ore. Up to 4 % of the world’s electricity production is spent annually on crushing rocks to obtain the necessary fraction of material, and for a single mine, the share of energy consumption for crushing can reach 50 % of the annual volume. In addition to spending electricity directly on rocks destruction, some of it is spent on creating a power reserve for a crushing machine (hereinafter referred to as a crusher) due to the fact that currently there is no single method of theoretical calculation of the power of its electric drive, no single method of determining energy costs for rocks destruction. It is known that raw materials extracted from different deposits have different physical and mechanical properties, which has a significant impact on the grinding process. However, difference in power of electric drive of crushing machines is due to the difference in their standard sizes, and the geography of their application is taken into account by the creation of the above-mentioned power reserve. The above factors have a negative impact on the operating costs of metallurgical industry enterprises. The article discusses some designs of crushers in which the destruction of the crushed piece occurs as a result of complex stress state. New design of a cone crusher with stops is proposed, which allows reducing energy costs for crushing materials. Due to the presence of stops and simple kinematics of the working body movement, reduction in the power necessary for the destruction of pieces of brittle materials, regardless of their properties, is achieved. At the same time, in crushed pieces destroyed in a cone crusher with stops, it is possible to create a shear stress state, in which theoretically a reduction in power required for crushing brittle materials is achieved by 2 times in comparison with compression crushers. The conditions of occurrence of shear stress state in crushed pieces during their crushing in a cone crusher with stops are described. The authors give recommendations for the reconstruction of these conditions.
The possibility of using jet metal heating
Authors: Laletina E. V. , Shatokhin K. S.
Published: November 2022

The international metallurgical World Steel Association has published new data that reviewing the situation in the global steel market. According to the published data for 2021 the production of steel on the world market decreased by 1 % (to 1.83 billion tons). The reduction in steel production on the world stage is the result of sharp fluctuations in market conditions associated with the pandemic. If it is necessary to urgently increase the volume of rolled metal production, the issues of uniformity of metal heating before rolling, stamping and forging, as well as improving the thermal operation of devices for heating the surface of slabs (which will simplify the design of heating devices, reduce the cost of heating and construction), are still relevant. One way to improve the heating process and increase the production of rolled metal is to use jet heating. This paper shows the results of modeling metal heating with nitrogen jets.
Features of microstructure, phase composition and strengthening capability of stainless steels with 13 – 17 % Cr
Authors: Pumpyanskii D. A. , Pyshmintsev I. Yu. , Bityukov S. M. , Gervas’ev M. A. , Gusev A. A.
Published: November 2022

The paper considers the study of the features of structure and phase transformations in high-strength, resistant to carbon dioxide corrosion, complex alloyed steels of martensitic, austenitic-martensitic and martensitic-ferritic classes with 13 – 17 % Cr. Influence of the alloying on crystallization and solid state phase transformations was revealed in the temperature range of hot deformation and heat treatment using thermodynamic modeling and experimental study. The effect of quenching temperature on the phase composition and microstructure was analyzed as a result of X-ray diffraction phase analysis, optical and transmission electron microscopy. It was found that increase of nickel content leads to growth of retained austenite fraction resulting in significant decrease of yield strength along with high tensile strength and elongation. To obtain predominantly martensitic microstructure in martensitic-austenitic steel, the multistage heat treatment is proposed including quenching, intermediate annealing for precipitation of dispersed carbides and tempering forming final mechanical properties. The composition of precipitated carbides was evaluated by X-ray microanalysis. The results of the tensile test for steels with martensitic and martensitic-ferritic microstructure showed that required strength grade (σ0.65 ≥ 862 MPa; σв ≥ 931 MPa) was reached after heat treatment including quenching and tempering. Multistage heat treatment including quenching, intermediate annealing and final tempering was resulted in required strength properties of high-nickel martensitic-austenitic steel with 15 % Cr.
Evolution of structure of rail steel lamellar pearlite under compression deformation
Authors: Aksenova K. V. , Gromov V. E. , Ivanov Yu. F. , Vashchuk E. S. , Peregudov O. A.
Published: November 2022

The article presents the results of analysis of evolution of the defective substructure of rail steel pearlite with lamellar morphology under deformation by uniaxial compression. The strain hardening of the studied steel under such deformation has a multistage character. Deformation of steel is accompanied by fragmentation of pearlite grains, which intensifies as the degree of deformation increases and reaches 0.4 of the studied foil volume at ε = 50 %. Fragments formed in ferrite plates are separated by low-angle boundaries. It was established that the average sizes of ferrite plate fragments decrease from 240 nm (ε = 15 %) to 200 nm (ε = 50 %) with an increase in the deformation degree. Fragmentation of cementite plates was revealed. It was found that the size of the fragments varies within 15 – 20 nm and weakly depends on the degree of steel deformation. Fracture of cementite lamellae, proceeding by their dissolution and cutting by mobile dislocations, was discovered. Carbon atoms that have passed from the crystal lattice of cementite to dislocations are carried out into the interlamellar space and form particles of tertiary cementite, the size of which is 2 – 4 nm. In the process of steel deformation, an inhomogeneous dislocation substructure is formed, which is due to the deceleration of dislocations by cementite particles. It was found that an increase in the deformation degree is accompanied by a decrease in the scalar and excess density of dislocations, which may be due to the escape of dislocations into low-angle boundaries, as well as their annihilation. It was established that the sources of internal stress fields are the interfaces between pearlite grains and colonies, cementite plates in pearlite grains, particles of the second phase located in the volume of ferrite plates.
Performance analysis of large wastewater treatment plants in Aracaju
Authors: Carvalho Conceição Matheus , Coêlho Mendonça Luciana , Máximo Almeida Albuquerque Tatiana
Published: November 2022

One of the biggest impacts on the country's water resources is the discharge of raw wastewater into rivers, which can be minimized with wastewater treatment. In this work, both the treatment systems performance used in four Wastewater Treatment Plants (WWTPs), which treat the domestic wastewater of Aracaju, and the compliance with the requirements of the current environmental legislation for the release of effluents were evaluated. To do so, physical-chemical, and bacteriological monitoring bulletins of the WWTPs were evaluated through the period of 1 year and 3 months. The WWTPs almost fully complied with all the conditions set out in the legislation for the parameters analyzed. Data analysis showed, in general, a better quality of the effluent from WWTP Orlando Dantas, with pollutant removal efficiencies very close to those found in the literature. However, the other stations, WWTP ERQ Norte, WWTP ERQ Sul and WWTP ERQ Leste, even fulfilling the legislation almost throughout all the studied period, achieved performance below expectations, due to the type of treatment technology adopted. With the evaluation of the results and the operating and maintenance conditions of the stations, it was concluded that there is a need to allocate resources for investments in a greater frequency of laboratory analysis and in the operation and maintenance of the infrastructure of the WWTPs. Furthermore, continuously training professionals involved in the operation of the systems will increase the performance of wastewater treatment structures. Consequently, there will have the improvement in the quality indices of treated wastewater, reduction of pollution and public health problems.
Fertirrigation in coffee: agronomic and sustainable aspects
Authors: Mantovani João Paulo Machado , Gabriel Filho Luis Roberto Almeida , Mantovani Camila Caroline Pantolfi , Leite Alisson Rodolfo , Mantovani Leandro Paloma
Published: November 2022

The present work aims to relate the positive effects of irrigation and mineral nutrition on coffee productivity, considering that the various existing methods and techniques involve a wide variation of dosage and nutrient splitting, due to the interaction between soil, water, climate, plant and area where the crop is located. Thus, through the methodology of literature review, a survey of research and theoretical notes of issues related to the benefits of irrigation and mineral nutrition was carried out, culminating in the focus of the fertigation technique. The study took into account aspects related to the rational use of water, the prevention of soil desertification and the Sustainable Development Goals of the UN 2030 Agenda. The analysis of the works and authors consulted made it possible to bring to the academic-scientific scope approaches that highlighted the fundamental role of fertigation in coffee farming.
Identificação da Microfauna Associada a Raízes do Mururé (Pistia stratiotes) e Relações com a Qualidade Ambiental
Authors: Moraes Arilson Quaresma de , Silva Natanael Charles da , Queiroz Marcelo Bruno Araújo , Araújo Magnólia Fernandes Florêncio de
Published: November 2022

O Brasil apresenta uma grande diversidade de espécies, fazendo com que haja um diversificado campo de estudos e investigações científicas nas mais variadas áreas de ensino e pesquisa. O presente estudo objetivou identificar a composição da microfauna associada as raízes do mururé (Pistia stratiotes) e sua importância na qualidade ambiental em um ecossistema aquático no município de Abaetetuba-PA. O estudo teve início com a observação e escolha do local de coleta, seguido da coleta do mururé e seu manejo em tanques apropriados com condições adequadas de armazenamento e manutenção. Em seguida, realizou-se a observação em microscópio óptico, finalizando com a identificação até ao nível taxonômico de gênero. Foram identificados 31 gêneros associados às raízes do mururé, dentro de dois grandes reinos (Animalia e Protista). A pesquisa aponta a existência de uma rica e diversificada microfauna associada às raízes da Pistia stratiotes no local de estudo, revelando que o ambiente em questão apresenta condições favoráveis para o crescimento e reprodução desse vegetal. Embora a presença de espécimes dos gêneros Brachionus e Anuraeopsis dê indícios de que o ambiente possa estar levemente eutrofizado, os demais indicadores apontaram para um ambiente livre de poluição e totalmente favorável à existência e desenvolvimento de espécies vegetais e animais.
Multifactor Authentication Key Management System based Security Model Using Effective Handover Tunnel with IPV6
Authors: Reddy Dhoma Harshavardhan , Sirisha N.
Published: November 2022

In the current modern world, the way of life style is being completely changed due to the emerging technologies which are reflected in treating the patients too. As there is a tremendous growth in population, the existing e-Healthcare methods are not efficient enough to deal with numerous medical data. There is a delay in caring of patient health as communication networks are poor in quality and moreover smart medical resources are lacking and hence severe causes are experienced in the health of patient. However, authentication is considered as a major challenge ensuring that the illegal participants are not permitted to access the medical data present in cloud. To provide security, the authentication factors required are smart card, password and biometrics. Several approaches based on these are authentication factors are presented for e-Health clouds so far. But mostly serious security defects are experienced with these protocols and even the computation and communication overheads are high. Thus, keeping in mind all these challenges, a novel Multifactor Key management-based authentication by Tunnel IPv6 (MKMA- TIPv6) protocol is introduced for e-Health cloud which prevents main attacks like user anonymity, guessing offline password, impersonation, and stealing smart cards. From the analysis, it is proved that this protocol is effective than the existing ones such as Pair Hand (PH), Linear Combination Authentication Protocol (LCAP), Robust Elliptic Curve Cryptography-based Three factor Authentication (RECCTA) in terms storage cost, Encryption time, Decryption time, computation cost, energy consumption and speed. Hence, the proposed MKMA- TIPv6 achieves 35bits of storage cost, 60sec of encryption time, 50sec decryption time, 45sec computational cost, 50% of energy consumption and 80% speed.