scholarly journals Investigation of a Turbogenerator Based on the Vortex Expansion Machine with a Peripheral Side Channel

2021 ◽  
Vol 8 (1) ◽  
pp. F11-F18
Author(s):  
S.M. Vaneev ◽  
V.S. Martsynkovskyy ◽  
A. Kulikov ◽  
D.V. Miroshnichenko ◽  
Ya.І. Bilyk ◽  
...  
Keyword(s):  
Electricity Generation ◽  
Experimental Studies ◽  
Geometric Parameters ◽  
Working Fluid ◽  
Advantages And Disadvantages ◽  
Lateral Channel ◽  
Different Types ◽  
Flow Part ◽  
Special Stand ◽  
Constant Improvement

The creation of energy-saving turbogenerators is an essential component of the development of small energy systems. The gradual growth of interest in distributed electricity generation necessitates the constant improvement of these units. Moreover, they implement a more environmentally friendly generation method than when using microturbine units that use fuel to carry out the work process. Nowadays, turbogenerators are created based on different types of expansion machines, which have their advantages and disadvantages, given in this article. Compared to competitors, vortex expansion machines have good prospects and the necessary potential to expand their research and produce turbogenerators. An experimental vortex expansion machine with a peripheral-lateral channel and ability to change the geometric parameters of its flowing part was created to meet these needs. Experimental studies of the machine were performed on a special stand with air as a working fluid. As a result of the tests, the data were successfully obtained and processed. They are presented in the form of tables and graphical dependencies. The nature of the influence of thermodynamic parameters and geometric parameters of the flow part on the efficiency of the vortex expansion machine and turbogenerator based on it to further improve and create new turbogenerators is clarified.

scholarly journals SELF-CLEANING FILTER FOR CLOSED HYDROSYSTEMS OF AGRICULTURAL EQUIPMENT

2021 ◽  
Vol 295 (2) ◽  
pp. 130-138
Author(s):  
M. STADNIK ◽  
◽  
А. VIDMYSH ◽  
S. SHARGORODSKIY ◽  
V. RUTKEVYCH ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Pressure Pulsation ◽  
Experimental Studies ◽  
Hydraulic Drive ◽  
Operating Mode ◽  
Working Fluid ◽  
Hydraulic Systems ◽  
Agricultural Equipment ◽  
Self Cleaning ◽  
Special Stand

The issue of increasing the reliability and durability of hydraulic units of closed hydraulic systems of agricultural equipment is considered, due to better cleaning of the working fluid by filtration units. The design of a self-cleaning filter with hydraulic automatic control of backwashing of slotted filtration elements with a counterflow of the working fluid is proposed. A special stand has been developed for simulating the operation of a self-cleaning filter of closed hydraulic systems of agricultural equipment. Experimental studies on a special stand confirmed the efficiency of the proposed design and made it possible to identify its main advantages in comparison with domestic and foreign counterparts. Based on the analysis of transient processes with increased pressure pulsation of agricultural equipment of a closed hydraulic drive, the actual pressure drop at which automatic flushing is triggered was established, compared with the calculated one, in which it was impossible to take into account such real factors as friction in the sealing units, the characteristics of the springs, distortions, tightness of valve pairs, fluctuations in dimensional chains. The most optimal operating mode of auto-washing equipment with a choke diameter of 1.0 mm has been determined. The auto-washing equipment was switched on at a pressure drop of 1.5 MPa (15 atm) and in an improved mode – pressure pulsations with an amplitude of 2 MPa (20 atm) when the auto-wash was turned off decreased in time to 0.12 s. It is noted that the developed self-cleaning filter for closed hydraulic systems of agricultural equipment will improve the reliability and increase the service life of the elements of hydraulic units and the machine itself as a whole.

scholarly journals FEATURES OF THE STAND AND METHODS FOR EXPERIMENTAL STUDIES OF PUMP-DOSING PUMPS OF HYDRAULIC STEERING SYSTEMS OF SELF-PROPELLED VEHICLES UNDER THE ASSOCIATED LOAD

2020 ◽  
pp. 14-21
Author(s):  
Oksana Motorna
Keyword(s):  
Experimental Studies ◽  
Hydraulic Cylinder ◽  
Steering System ◽  
Working Fluid ◽  
Hydraulic Motor ◽  
Pump Operation ◽  
Input Shaft ◽  
Working Volume ◽  
Actual Flow Rate ◽  
Special Stand

The article discusses a special stand for experimental research of dosing pumps of hydrostatic steering systems of self-propelled machines, which makes it possible to analyze the quality of the dosing pump under conditions that correspond to different control actions and loads that arise during the operation of the steering system. An electro-hydraulic scheme of the stand has been developed to determine the characteristics of a dosing pump under the action of a associated load. The characteristics of control and measuring devices for determining parameters that are controlled both in statics and in dynamics are presented. To record changes in signals over time, a recording system has been developed that realizes the recording of signals on a computer and their processing using the «PowerGraph» program. A feature of this stand is that the load for the dosing pump is formed in the form of a pressure drop in its outlet channels. This makes it possible to evaluate the performance of these products regardless of their working volume and facilitates the experimental study of the behavior of the system when reproducing certain modes of its operation over a period of time that is not limited to the stroke of the executive hydraulic cylinder of the steering system. The stand implements an original technique for reproducing the associated load in the outgoing channels of the dosing pump, for which an additional pump driven by a hydraulic motor is installed in the outgoing channels of the metering pump. Regulation of the speed of rotation of the drive motor makes it possible to set the required value of the associated load. The method for determining the quality indicator of the dosing pump operation under the action of a associated load is briefly described In this case, the indicator of relative flow rates in the outgoing channels of the metering pump is determined, which shows how many times the actual flow rate of the working fluid increases in comparison with the nominal one, which is determined for the dosing pump with a certain working volume by the speed of rotation of the input shaft.

scholarly journals A review of experiments in tourism and hospitality

2021 ◽  
Author(s):  
Giampaolo Viglia ◽  
Sara Dolnicar
Keyword(s):  
Social Sciences ◽  
External Validity ◽  
Experimental Studies ◽  
Knowledge Development ◽  
Practical Implementation ◽  
Advantages And Disadvantages ◽  
The Social ◽  
Different Types ◽  
Alternative Research ◽  
Tourism And Hospitality

Well-designed and executed experiments prove cause-and-effect relationships. The ability to draw causal conclusions is critical to knowledge development in any field of research. In this article, we discuss the benefits of experimental designs over alternative research approaches for the social sciences, discuss advantages and disadvantages of different types of experiments, review existing experimental studies specific to tourism and hospitality, and offer guidance to researchers who wish to conduct such studies. Properly executed experiments using actual behaviour of real stakeholders as a dependent variable lead to conclusions with high external validity. Our discussion of practical implementation issues culminates in a checklist for researchers. The article launches the Annals of Tourism Research Curated Collection on experimental research in tourism.

A Study of Electroerosive Machinability of Heat-Resistant Alloys in Relation to the Technology of Piercing Small Diameter Holes

2020 ◽  
pp. 69-75
Author(s):  
S.B. Kushnarenko ◽  
Y.P. Astakhov ◽  
A.O. Fomichev
Keyword(s):  
Pulse Energy ◽  
Experimental Studies ◽  
Small Diameter ◽  
Geometric Parameters ◽  
Working Fluid ◽  
Calculation Error ◽  
Workpiece Material ◽  
Segment Model ◽  
Heat Resistant ◽  
Interelectrode Gap

This article presents a method of obtaining and analyzing a single electroerosion hole for a group of heat-resistant chromium-nickel alloys. The study of the geometric parameters of the hole allows us to calculate experimentally the coefficient of erosion of the workpiece material, which characterizes the efficiency of converting the electrical energy into the fracture work of a solid body. When a single erosion pulse is applied to the interelectrode gap, a single hole is formed on the electrode surface. The geometric parameters of the hole (diameter, depth, height of the collar) depend on many factors: the pulse energy, the composition of the working fluid, the material of the electrodes, the value of the interelectrode gap, etc. This study establishes the dependence of the volume of the removed material on the pulse energy, with other conditions being equal. Experimental studies are conducted in accordance with a well-known method, and photographs of individual holes are obtained for different pulse durations. Ball segment and ellipsoid models are proposed for calculating the volume of the removed metal. It is shown that the ball segment model yields the smallest calculation error. The volume of individual holes is calculated using the selected ball segment model.

METHODS FOR SIMULATION OF ACUTE BRAIN ISCHEMIA: PATHOPHYSIOLOGICAL SUBSTANTIATION OF SELECTION AND IMPORTANCE FOR CLINICAL PRACTICE

2019 ◽  
pp. 142-152
Author(s):  
Б.И. Гельцер ◽  
Э.В. Слабенко ◽  
Ю.В. Заяц ◽  
В.Н. Котельников
Keyword(s):  
Clinical Practice ◽  
Experimental Studies ◽  
Cerebrovascular Diseases ◽  
Experimental Models ◽  
Pathological Process ◽  
Ischemic Brain ◽  
Actual Clinical Practice ◽  
Acute Cerebral Ischemia ◽  
Different Types ◽  
Acute Brain Ischemia

Одним из основных требований к разработке экспериментальных моделей цереброваскулярных заболеваний является их максимальная приближенность к реальной клинической практике. В работе систематизированы данные по основным методам моделирования острой ишемии головного мозга (ОИГМ), представлена их классификация, анализируются данные о преимуществах и недостатках той или иной модели. Обсуждаются результаты экспериментальных исследований по изучению патогенеза ОИГМ с использованием различных моделей (полной и неполной глобальной, локальной и мультифокальной ишемии) и способов их реализации (перевязка артерий, клипирование, коагуляция, эмболизация и др.). Особое внимание уделяется «стабильности» последствий острого нарушения мозгового кровообращения: необратимых ишемических повреждений головного мозга или обратимых с реперфузией заданной продолжительности. Отмечается, что важное значение в этих исследованиях должно принадлежать современным методам прижизненной визуализации очагов острого ишемического повреждения, что позволяет оценивать динамику патологического процесса. Предлагаемый метод отвечает требованиям гуманного обращения с животными. Подчеркивается, что выбор релевантной модели ОИГМ определяется задачами предстоящего исследования и технологическими ресурсами научной лаборатории. Development of experimental models for acute forms of cerebrovascular diseases is essential for implementation of methods for their prevention and treatment. One of the principal requirements to such models is their maximum approximation to actual clinical practice. This review systematized major models of acute cerebral ischemia (ACI), their classification, and presented information about their advantages and shortcomings. Also, the review presented results of experimental studies on pathophysiological mechanisms of different types of modeled ACI (complete and incomplete global, local, and multifocal ischemia) and methods for creating these models (arterial ligation, clipping, coagulation, embolization, etc.). Particular attention was paid to “stability” of the consequences of acutely impaired cerebral circulation - an irreversible ischemic brain injury or a reversible injury with reperfusion of a given duration. The authors emphasized that in such studies, a special significance should be given to intravital imaging of acute ischemic damage foci using modern methods, which allow assessing the dynamics of the pathological process and meet the requirements to humane treatment of animals. The choice of a relevant ACI model is determined by objectives of the planned study and the technological resources available at the research laboratory.

Studies on Chemical Methods to Expose Gate/Tunnel Oxide and Identification of Gate/Tunnel Oxide Defects in Wafer Fabrication

2002 ◽  
Author(s):  
Y. N. Hua ◽  
G. B. Ang ◽  
S. Redkar ◽  
Yogaspari ◽  
Wilma Richter
Keyword(s):  
Acetic Acid ◽  
Silicon Oxide ◽  
Wafer Fabrication ◽  
Chemical Methods ◽  
Advantages And Disadvantages ◽  
Different Types ◽  
Capacitor Structure ◽  
Oxide Defects ◽  
Buffer Oxide Etchant ◽  
Etch Time

Abstract In failure analysis of wafer fabrication, currently, three different types of chemical methods including 6:6:1 (Acetic Acid/HNO3/HF), NaOH and Choline are used in removing polysilicon (poly) layer and exposing the gate/tunnel oxide underneath. However, usage is limited due to their disadvantages. For example, 6:6:1 is a relatively fast etchant, but it is difficult to control the etch time and keep the oxide layer intact. Also, while using NaOH to remove poly and expose the silicon oxide, the solution needs to be heated. It is also difficult to etch a poly layer with a WSix or a CoSix silicide using NaOH. In this paper, we will discuss these 3 etchants in terms of their advantages and disadvantages. We will then introduce a new poly etchant, called HB91. HB91 is useful for removing poly to expose the gate/tunnel oxide for identification of related defects. HB91 is actually a mixture of two chemicals namely nitric acid (HNO3) and buffer oxide etchant (BOE) in a 9:1 ratio. The experimental results show that it is highly selective in poly removal with respect to the gate/tunnel oxide and is a suitable poly etchant especially for removing polysilicon with/without WSix and CoSix in the large capacitor structure. Application results of this poly etchant (HB91) will be presented.

scholarly journals Melatonin in Cancer Treatment: Current Knowledge and Future Opportunities

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2506
Author(s):  
Wamidh H. Talib ◽  
Ahmad Riyad Alsayed ◽  
Alaa Abuawad ◽  
Safa Daoud ◽  
Asma Ismail Mahmod
Keyword(s):  
Clinical Trials ◽  
Current Knowledge ◽  
Biological Activities ◽  
Experimental Studies ◽  
Therapeutic Effects ◽  
Cell Proliferation Inhibition ◽  
Different Types ◽  
Solid Foundation

Melatonin is a pleotropic molecule with numerous biological activities. Epidemiological and experimental studies have documented that melatonin could inhibit different types of cancer in vitro and in vivo. Results showed the involvement of melatonin in different anticancer mechanisms including apoptosis induction, cell proliferation inhibition, reduction in tumor growth and metastases, reduction in the side effects associated with chemotherapy and radiotherapy, decreasing drug resistance in cancer therapy, and augmentation of the therapeutic effects of conventional anticancer therapies. Clinical trials revealed that melatonin is an effective adjuvant drug to all conventional therapies. This review summarized melatonin biosynthesis, availability from natural sources, metabolism, bioavailability, anticancer mechanisms of melatonin, its use in clinical trials, and pharmaceutical formulation. Studies discussed in this review will provide a solid foundation for researchers and physicians to design and develop new therapies to treat and prevent cancer using melatonin.

Experimental Studies on Axially Loaded Concrete Columns Confined by Different Materials

2008 ◽  
Vol 400-402 ◽  
pp. 513-518 ◽  
Author(s):  
Yong Chang Guo ◽  
Pei Yan Huang ◽  
Yang Yang ◽  
Li Juan Li
Keyword(s):  
Bearing Capacity ◽  
Glass Fiber ◽  
Failure Modes ◽  
Experimental Studies ◽  
Concrete Columns ◽  
Steel Tube ◽  
Ultimate Bearing Capacity ◽  
Advantages And Disadvantages ◽  
Axially Loaded ◽  
Normal Strength

The improvement of the load carrying capacity of concrete columns under a triaxial compressive stress results from the strain restriction. Under a triaxial stress state, the capacity of the deformation of concrete is greatly decreased with the increase of the side compression. Therefore, confining the deformation in the lateral orientation is an effective way to improve the strength and ductility of concrete columns. This paper carried out an experimental investigation on axially loaded normal strength concrete columns confined by 10 different types of materials, including steel tube, glass fiber confined steel tube (GFRP), PVC tube, carbon fiber confined PVC tube (CFRP), glass fiber confined PVC tube (GFRP), CFRP, GFRP, polyethylene (PE), PE hybrid CFRP and PE hybrid GFRP. The deformation, macroscopical deformation characters, failure mechanism and failure modes are studied in this paper. The ultimate bearing capacity of these 10 types of confined concrete columns and the influences of the confining materials on the ultimate bearing capacity are obtained. The advantages and disadvantages of these 10 types of confining methods are compared.

Think about it – can portrayals of homosexuality in advertising prime consumer-perceived social connectedness and empathy?

2017 ◽  
Vol 51 (1) ◽  
pp. 82-98 ◽  
Author(s):  
Nina Åkestam ◽  
Sara Rosengren ◽  
Micael Dahlen
Keyword(s):  
Design Methodology ◽  
Social Connectedness ◽  
Experimental Studies ◽  
Social Effects ◽  
Attitudes Toward Homosexuality ◽  
Content Type ◽  
Advantages And Disadvantages ◽  
Thought Listing ◽  
Societal Level ◽  
Practical Implications

Purpose This paper aims to investigate whether portrayals of homosexuality in advertising can generate social effects in terms of consumer-perceived social connectedness and empathy. Design/methodology/approach In three experimental studies, the effects of advertising portrayals of homosexuality were compared to advertising portrayals of heterosexuality. Study 1 uses a thought-listing exercise to explore whether portrayals of homosexuality (vs heterosexuality) can evoke more other-related thoughts and whether such portrayals affect consumer-perceived social connectedness and empathy. Study 2 replicates the findings while introducing attitudes toward homosexuality as a boundary condition and measuring traditional advertising effects. Study 3 replicates the findings while controlling for gender, perceived similarity and targetedness. Findings The results show that portrayals of homosexuality in advertising can prime consumers to think about other people, thereby affecting them socially. In line with previous studies of portrayals of homosexuality in advertising, these effects are moderated by attitudes toward homosexuality. Research limitations/implications This paper adds to a growing body of literature on the potentially positive extended effects of advertising. They also challenge some of the previous findings regarding homosexuality in advertising. Practical implications The finding that portrayals of homosexuality in advertising can (at least, temporarily) affect consumers socially in terms of social connectedness and empathy should encourage marketers to explore the possibilities of creating advertising that benefits consumers and brands alike. Originality/value The paper challenges the idea that the extended effects of advertising have to be negative. By showing how portrayals of homosexuality can increase social connectedness and empathy, it adds to the discussion of the advantages and disadvantages of advertising on a societal level.

Lexical-Grammatical Status and Lexicographic Presentation of Two-Component Stable Prepositional Combinations

2021 ◽  
pp. 32-51
Author(s):  
Elena V. Generalova ◽  
Keyword(s):  
Summary Table ◽  
Complex Issue ◽  
Dictionary Entry ◽  
Figurative Meaning ◽  
Advantages And Disadvantages ◽  
Unresolved Question ◽  
Two Component ◽  
Different Types ◽  
Syntactic Properties ◽  
Theoretical Issues

The aim of the article is to review the ways of dictionary presentation of stable prepositional combinations and the factors essential for their lexical-grammatical status and the type of optimal lexicographic description. The object of the study is twocomponent prepositional combinations with stable meanings and the “preposition+noun” structure. The material of the article is data of different dictionaries of Russian presenting stable prepositional combinations. In the course of the study, the following questions were answered: why the definition and interpretation of the lexical-grammatical nature of stable prepositional combinations are so difficult and ambiguous; what lexicographic interpretation these units have in dictionaries of different types; what the advantages and disadvantages of different ways of dictionary interpretation of such language material are. The following methods were used: introspective (observation, generalization, classification), systematic lexicographic description according to dictionary parameters, dictionary definition analysis. The summary table of the lexicographic presentation of stable combinations allows seeing both the unresolved question of dictionary interpretation of such units and the patterns of their interpretation depending on the type of a dictionary. As a result of the analysis the following conclusions were drawn. 1) In modern Russian there is a rather large (about 2,000 units) class of language units (prepositional combinations), the lexical-grammatical status of which is not defined, and there is no term for their definition; this class is historically formed and continues to replenish. 2) The type of dictionary presentation of stable prepositional combinations is determined by the dictionary concept, grammatical and syntactic properties, presence of figurative meaning and possibility of component variation of such combinations. 3) The unresolved theoretical issues have as a result the lexicographic discrepancy in the presentation of these language units. Extreme lexicographic solutions are a separate dictionary entry for each combination and the presentation of such units only as stable combinations in the entry of a noun (presented in academic explanatory dictionaries). 4) Taking into account only the factor of presence/absence of a gap seems to formalize the dictionary presentation of adverbs with both conjoined and split spelling, really existing in Russian, and the position of recognition of these units with independent words and their isolate presentation is not impeccable for dictionary users. 5) In the author’s opinion, the presentation of stable prepositional combinations exclusively as independent vocabules is inferior to the traditional lexicographic approach because the isolated presentation of this material breaks the semantic connections of these complex lexical units; the most complex issue is the differentiation of adverbs with split spelling and stable combinations.

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