Reliability and maintainability of scraper conveyor used in coal mining in the Jiu Valley

Purpose. The aim of the study is to determine and analyse causes of faults in the operation of TR-7A scraper conveyor and to estimate the required time for their remediation and select the methods of their prevention and elimination. Methods. The characteristic of a system, such as the scraper conveyor, intended to fulfil its specified function in time and operation conditions, can be studied, theoretically, by determining its operational reliability. This implies the existence of a framework that incorporates several interconnected components of technical, operational, commercial and management nature. The quantitative expression of reliability was based on elements of mathematical probability theory and statistics (exponential distribution law), failure and repair mechanism not being subject to certain laws. Findings. The following TR-7A subassemblies, if defective, could have been the cause of a failure: chains, hydraulic couplings, chain lifters, drive, return drums, some electrical equipment. After 28 months of monitoring the TR-7A operation, we have established the number of failures (defects) ni, the operating time between failures ti, frequency of failures fc, time to repair tri, weight repair time pr, mean time between failures (MTBF), mean time to repair (MTR). Originality. Data collection and processing involves the adoption of specific procedures to allow the correct highlighting of the causes and frequency of failures. The accomplishment of this approach allowed finding the solutions for increasing reliability of some subassemblies of TR-7A conveyor (i.e., those subjected to abrasive wear). Practical implications. One solution was to use materials with compositional and functional gradient in the case of worn surfaces of some subassemblies. It was successfully applied for the chain lifters where a significant increase in the mean time between failures was obtained. The field of application of these materials can be extended to the metal subassemblies of machines and equipment with abrasion wear that occurs both in underground mines and in quarries.Мета. Визначення та аналіз причин несправностей у роботі скребкового конвеєра, оцінка часу їх усунення та вибір методів їх запобігання й ліквідації при видобутку вугілля. Методика. Скребковий конвеєр ТР-7А, який призначений для виконання заданої функції у часі та в певних умовах експлуатації був теоретично вивчено шляхом визначення його експлуатаційної надійності. Це має на увазі наявність структури, яка включає кілька взаємопов’язаних компонентів технічного, експлуатаційного, комерційного та управлінського характеру. Кількісне вираження надійності засноване на елементах математичної теорії ймовірностей і статистики (експоненціального закону розподілу); з урахуванням того, що механізм поломки і ремонту обладнання не підпорядковується певним законам. Результати. Визначено вузли конвеєра TR-7A, які в разі несправності, можуть бути причиною відмови в роботі: ланцюги, гідравлічні муфти, ланцюгові підйомники, привід, поворотні барабани, деякий електричне обладнання. Після 28 місяців моніторингу роботи TR-7A було визначено кількість поломок (несправностей) ni, робочий час між поломками ti, частота поломок fc, час ремонту tri, вагова частка часу ремонту pr, середній час між поломками (MTBF), середній час ремонту (MTR). Наукова новизна. Встановлено коректні причини і частота збоїв у роботі скребкових конвеєрів на основі нового підходу збору та обробки експериментальних даних. Реалізація даного підходу дозволила знайти рішення для підвищення надійності деяких вузлів конвеєра ТР-7А, схильних до абразивного зносу. Практична значимість. Одним з рішень було використання матеріалів з композиційним і функціональним градієнтом для відновлення зношених поверхонь деяких вузлів. Цей підхід був успішно застосований для ланцюгових підйомників, в результаті чого середній час між поломками значно збільшився. Такі матеріали можуть застосовуватися для відновлення металевих вузлів машин і устаткування, схильних до абразивного зносу як при підземній, так і відкритій розробці родовищ.Цель. Определение и анализ причин неисправностей в работе скребкового конвейера, оценка времени их устранения и выбор методов их предотвращения и ликвидации при добыче угля. Методика. Скребковый конвейер ТР-7А, который предназначен для выполнения заданной функции во времени и в определенных условиях эксплуатации, был теоретически изучен путем определения его эксплуатационной надежности. Это подразумевает наличие структуры, которая включает несколько взаимосвязанных компонентов технического, эксплуатационного, коммерческого и управленческого характера. Количественное выражение надежности основано на элементах математической теории вероятностей и статистики (экспоненциального закона распределения); с учетом того, что механизм поломки и ремонта оборудования не подчиняется определенным законам. Результаты. Определены узлы конвейера TR-7A, которые в случае неисправности, могут быть причиной отказа в работе: цепи, гидравлические муфты, цепные подъемники, привод, возвратные барабаны, некоторое электрическое оборудование. После 28 месяцев мониторинга работы TR-7A было определено количество поломок (неисправностей) ni, рабочее время между поломками ti, частота поломок fc, время ремонта tri, весовая доля времени ремонта pr, среднее время между поломками (MTBF), среднее время ремонта (MTR). Научная новизна. Установлены корректные причины и частота сбоев в работе скребковых конвейеров на основе нового подхода сбора и обработки экспериментальных данных. Реализация данного подхода позволила найти решения для повышения надежности некоторых узлов конвейера ТР-7А, подверженных абразивному износу. Практическая значимость. Одним из решений было использование материалов с композиционным и функциональным градиентом для восстановления изношенных поверхностей некоторых узлов. Этот подход был успешно применен для цепных подъемников, в результате чего среднее время между поломками значительно увеличилось. Такие материалы могут применяться для восстановления металлических узлов машин и оборудования, подверженных абразивному износу как при подземной, так и открытой разработке месторождений.This work has been carried out without any funding from a grant or scientific project

EDUCATION THROUGH INNOVATION IN THE FIELD OF METALLIC MATERIALS SCIENCE

The importance of the innovation process lies in its main functions, those of generating and leading to the conception and development of new processes and products, based on creativity. Hence the need of education for innovation. In this article we present, for a start, the main stages of an innovation process. Then, elements of innovation management, innovation strategies, innovation activities. We also present aspects regarding the financing of the innovation process and of the technology transfer. As results of the efficient application of these theoretical elements specific to an innovation process, we present the main elements of a patent (Invention Patent no. 107025/1993) of one of the authors. This patent, entitled "Burner" has gone through all stages, from conception to implementation in industry. This implementation took place in the former Special Steels Plant ok Targoviste (COST), in Electric Steel Mill no. 1 (OE1), with a good technological and economic efficienc

Congenital Abnormalities of the Fetal Heart

Congenital heart defects (CHDs) are the most frequent congenital malformations, the costliest hospital admissions for structural defects and the leading cause of infant general and malformations related mortality. Fetal echocardiography represents a skilled ultrasound examination, because of the complexity, physiological and structural particularities of the fetal heart. The efficiency of the cardiac scan is reported with great variation, depending on the scanning protocol, examiner experience and equipment quality but CHDs remains among the most frequently missed congenital abnormalities

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

Risk analysis in credit activity

The present period is characterized by extensive processes of economic and financial turbulence, both in terms of companies and in terms of banking companies, having as objectives the promotion and the implementation of some methodologies apllied on European and global level. The purpose of credit analisys is to avoid loss of profit due to bad debt, because of granting loans to customers who cannot refunded debt or because of not granting loans to good potential customers. From this perspective risk analysis in lending activity represents an area of major importance in lending activity, finally expressing opinion about sincerity certification of financial statements, the confirmation of the legal provisions in force, the followingof the management principles of companies under review.credit risk, lending activity, bank companies, credit analysis, performance.

A Blockchain-Enabled Framework for mHealth Systems

Presently modern technology makes a significant contribution to the transition from traditional healthcare to smart healthcare systems. Mobile health (mHealth) uses advances in wearable sensors, telecommunications and the Internet of Things (IoT) to propose a new healthcare concept centered on the patient. Patients’ real-time remote continuous health monitoring, remote diagnosis, treatment, and therapy is possible in an mHealth system. However, major limitations include the transparency, security, and privacy of health data. One possible solution to this is the use of blockchain technologies, which have found numerous applications in the healthcare domain mainly due to theirs features such as decentralization (no central authority is needed), immutability, traceability, and transparency. We propose an mHealth system that uses a private blockchain based on the Ethereum platform, where wearable sensors can communicate with a smart device (a smartphone or smart tablet) that uses a peer-to-peer hypermedia protocol, the InterPlanetary File System (IPFS), for the distributed storage of health-related data. Smart contracts are used to create data queries, to access patient data by healthcare providers, to record diagnostic, treatment, and therapy, and to send alerts to patients and medical professionals

Investigation of Opto-Electronic Properties and Stability of Mixed-Cation Mixed-Halide Perovskite Materials with Machine-Learning Implementation

The feasibility of mixed-cation mixed-halogen perovskites of formula AxA’1−xPbXyX’zX”3−y−z is analyzed from the perspective of structural stability, opto-electronic properties and possible degradation mechanisms. Using density functional theory (DFT) calculations aided by machine-learning (ML) methods, the structurally stable compositions are further evaluated for the highest absorption and optimal stability. Here, the role of the halogen mixtures is demonstrated in tuning the contrasting trends of optical absorption and stability. Similarly, binary organic cation mixtures are found to significantly influence the degradation, while they have a lesser, but still visible effect on the opto-electronic properties. The combined framework of high-throughput calculations and ML techniques such as the linear regression methods, random forests and artificial neural networks offers the necessary grounds for an efficient exploration of multi-dimensional compositional spaces

PCR coupled with mass-spectrometry for detection of Clostridium difficile virulence markers during the emergence of ribotype 027 in Bucharest area

In recent years Clostridium difficile infection (CDI) has represented a serious public health issue, mainly due to the global spread of the hypervirulent strain NAP1/027/BI. The purpose of the present study was to evaluate the utility of a PCR coupled with electrospray ionization mass spectrometry (ESI-MS) commercial assay for the detection of C. difficile virulence markers. Non-duplicative C. difficile isolates from patients with CDI diagnosed in a tertiary level hospital from Bucharest were tested for toxin A, toxin B, binary toxin genes and deletion in tcdC gene using PCR/capillary gel electrophoresis and PCR/ESI-MS. The study analysed 45 non-duplicative isolates, 33 strains (73.3%) belonging to ribotype 027. The concordance between PCR/capillary gel electrophoresis and PCR/ESI-MS was 100% for toxin A gene, 97.8% for toxin B gene, 91.1% for binary toxin subunit A gene and 95.6% for binary toxin subunit B gene. The general concordance for the complete panel of markers was 88.9% but was 100% for ribotype 027 isolates. PCR/ESI-MS might be a valid method for the detection of C. difficile virulence markers, including binary toxin

Severe Austrian Syndrome in an Immunocompromised Adult Patient – A Case Report

Background: Known also as Osler’s triad, Austrian syndrome is a complex pathology which consists of pneumonia, meningitis and endocarditis, all caused by the haematogenous dissemination of Streptococcus pneumoniae. The multivalvular lesions are responsible for a severe and potential lethal outcome