scholarly journals Simulation Study on Dynamics of Hydraulic Turbines Used in Drilling Engineering

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Yijin Zeng ◽  
Jin Wang ◽  
Shidong Ding ◽  
Haobo Zhou ◽  
Yanbin Zang ◽  
...  
Keyword(s):  
External Load ◽  
Solid Phase ◽  
Design Method ◽  
Wide Range ◽  
Aero Engines ◽  
Turbine Design ◽  
Water Turbines ◽  
The Impact ◽  
External Loads ◽  
Starting Torque

Hydroturbines have a very wide range of applications, which are commonly found in wind turbines, water turbines, aero engines, etc. This paper provided a detailed turbine design and a design method of turbine blade shape. Using the CFD (computational fluid dynamics) method, based on the realizable k-ɛ turbulence model and Euler multiphase flow model, the effects of different external loads, blade numbers, blade installation angles, and flow rates on the force condition of turbine and the influence of different solid contents, particle sizes, and densities on turbine performance were studied. The simulation results show that, under the action of fluid, when the starting torque of turbine is larger than the external load, the turbine starts to move, the angular velocity increases until it remains constant, the absolute value of impact force decreases, and the impact torque decreases until it is equal to the external load; while the starting torque of turbine is smaller than the external load, the turbine stays still. The increase of the particle size, content, and density of the solid phase will lead to an increase in the torque and pressure drop of the turbine and ultimately leads to the increase of turbine input, output power, and efficiency.

External and internal Load and their Effects on Professional Volleyball Training

2020 ◽  
Vol 41 (07) ◽  
pp. 468-474
Author(s):  
Ricardo Franco Lima ◽  
Ana Silva ◽  
José Afonso ◽  
Henrique Castro ◽  
Filipe Manuel Clemente
Keyword(s):  
External Load ◽  
Inertial Measurement Unit ◽  
Perceived Exertion ◽  
Measurement Unit ◽  
Internal Load ◽  
Monitoring Process ◽  
Accurate Perception ◽  
Positive Correlations ◽  
The Impact ◽  
External Loads

AbstractThe purpose of this study was twofold: (i) characterize the external and internal training load of professional volleyball players with a focus on intra-week changes and (ii) test the relationships between internal and external load measures. Eight male professional players (age: 23.0±5.22 yo; body mass: 84.5 ± 7.58 kg; height: 193.0±9.71 cm; BMI: 22.0±0.02 kg/m2) were monitored daily over 15 weeks. The monitoring process included both internal (rate of perceived exertion [RPE] and session-RPE [s-RPE]) and external load variables, which were measured by an inertial measurement unit. Results revealed that, within-week variations revealed that RPE was significantly higher during MD-2 (d=0.59) and MD-3 (d=0.56) than MD-1. A significantly higher number of jumps was observed on MD-2 than MD-1 (d=0.69). Considering the relationships between internal and external load measures, small positive correlations were found between RPE and the number of jumps (r=0.17) and between s-RPE and the number of jumps (r=0.49). In conclusion, a tapering strategy was observed on the day before a match, as internal and external loads decreased. Both internal and external load measures are necessary to provide an accurate perception of the impact of training stimuli on players.

scholarly journals Multivariate Assessment of Procedures for Molecularly Imprinted Polymer Synthesis for Pesticides Determination in Environmental and Agricultural Samples

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7078
Author(s):  
Mariusz Marć ◽  
Marta Bystrzanowska ◽  
Katarzyna Pokajewicz ◽  
Marek Tobiszewski
Keyword(s):  
Sample Preparation ◽  
Solid Phase ◽  
Food Samples ◽  
Mechanical Resistance ◽  
Molecularly Imprinted ◽  
Innovative Strategies ◽  
Wide Range ◽  
Analytical Procedures ◽  
Pre Treatment ◽  
The Impact

In the case of quantitative and qualitative analysis of pesticides in environmental and food samples, it is required to perform a sample pre-treatment process. It allows to minimalize the impact of interferences on the final results, as well as increase the recovery rate. Nowadays, apart from routinely employed sample preparation techniques such as solid-phase extraction (SPE) or solid-phase microextraction (SPME), the application of molecularly imprinted polymers (MIPs) is gaining greater popularity. It is mainly related to their physicochemical properties, sorption capacity and selectivity, thermo-mechanical resistance, as well as a wide range of polymerization techniques allowing to obtain the desired type of sorption materials, adequate to a specific type of pesticide. This paper targets to summarize the most popular and innovative strategies since 2010, associated with the MIPs synthesis and analytical procedures for pesticides determination in environmental and food samples. Application of multi-criteria decision analysis (MCDA) allows for visualization of the most beneficial analytical procedures in case of changing the priority of each step of analysis (MIPs synthesis, sample preparation process—pesticides extraction, chromatographic analysis) bearing in mind metrological and environmental issues.

scholarly journals USE OF MECHANOCHEMICAL ACTIVATION TO CONTROL RHEOLOGICAL PROPERTIES OF MOULDING PASTES FOR CATALYSTS AND SORBENTS EXTRUSION

2017 ◽  
Vol 60 (1) ◽  
pp. 102
Author(s):  
Nataliya Svyatenko ◽  
Valery Yu. Prokof’ev ◽  
Natalya E. Gordina
Keyword(s):  
Rheological Properties ◽  
Mechanochemical Activation ◽  
Solid Phase ◽  
Critical Shear Stress ◽  
Coherent Scattering ◽  
Coherent Scattering Region ◽  
Shear Loading ◽  
Flow Index ◽  
Wide Range ◽  
The Impact

For citation:Svyatenko N., Prokof’ev V.Yu., Gordina N.E. Use of mechanochemical activation to control rheological properties of moulding pastes for catalysts and sorbents extrusion. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 1. P. 102-107.The influence humidity, grinding and mechanical activation of the solid phase on the rheological properties of the molding paste for extrusion of catalysts and sorbents was studied. The following parameters of the molding pastes were investigated, namely the coagulation structure strength, the flow index, the maximum plastic viscosity, the critical shear stress, plasticity, the r (stuelaxation period), the ratio of deformations. In order to characterize the degree of mechanochemical activation, the dimension of the coherent scattering region and the microdeformations value were used. Increasing the degree of mechanochemical activation of the solid phase was shown to allow controlling the properties of molding pastes in a more wide range. In the technology of extruded catalysts and sorbents, the mills-activators with the impact-shear loading are proposed to use. The mills with an average value of power density (up to 6 kW/kg) were recommended.

scholarly journals Robust Aerodynamic Design of Nacelles for Future Civil Aero-Engines

2020 ◽  
Author(s):  
B. Deneys J. Schreiner ◽  
Fernando Tejero ◽  
David G. MacManus ◽  
Christopher Sheaf
Keyword(s):  
Design Method ◽  
Operating Conditions ◽  
Propulsive Efficiency ◽  
Multi Objective ◽  
Fuel Burn ◽  
Trade Offs ◽  
Specific Thrust ◽  
Aero Engines ◽  
The Impact ◽  
Bypass Ratio

Abstract As the growth of aviation continues it is necessary to minimise the impact on the environment, through reducing NOx emissions, fuel-burn and noise. In order to achieve these goals, the next generation of Ultra-High Bypass Ratio engines are expected to increase propulsive efficiency through operating at reduced specific thrust. Consequently, there is an expected increase in fan diameter and the associated potential penalties of nacelle drag and weight. In order to ensure that these penalties do not negate the benefits obtained from the new engine cycles, it is envisaged that future civil aero-engines will be mounted in compact nacelles. While nacelle design has traditionally been tackled by multi-objective optimisation at different flight conditions within the cruise segment, it is anticipated that compact configurations will present larger sensitivity to off-design conditions. Therefore, a design method that considers the different operating conditions that are met within the full flight envelope is required for the new nacelle design challenge. The method is employed to carry out multi-point multi-objective optimisation of axisymmetric aero-lines at different transonic and subsonic operating conditions. It considers mid-cruise conditions, end-of-cruise conditions, the sensitivity to changes in flight Mach number, windmilling conditions with a cruise engine-out case and an engine-out diversion scenario. Optimisation routines were conducted for a conventional nacelle and a future aero-engine architecture, upon which the aerodynamic trade-offs between the different flight conditions are discussed. Subsequently, the tool has been employed to identify the viable nacelle design space for future compact civil aero-engines for a range of nacelle lengths.

scholarly journals Studies on the Efficiency of the Impact of Paraffin Inhibitors on Lowering the WAT Temperature and Reducing the Amount of Paraffin Deposit

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4653
Author(s):  
Sławomir Szuflita ◽  
Michał Pajda ◽  
Jerzy Kuśnierczyk ◽  
Mirosław Wojnicki ◽  
Marcin Warnecki
Keyword(s):  
Crude Oil ◽  
Additional Data ◽  
Solid Phase ◽  
Temperature Drop ◽  
Equilibrium Conditions ◽  
Wax Precipitation ◽  
Solid Paraffin ◽  
Wide Range ◽  
The Impact

This paper discusses the issues of the impact of pressure and temperature on the precipitation of paraffin deposits from reservoir fluids in the presence of previously prepared paraffin inhibitors. Using a properly modified PVT apparatus, the temperature of the beginning of paraffin precipitation (wax appearance temperature—WAT) has been determined, below which the solid paraffin phase was captured on a specialized filter in various temperatures. Based on the conducted experiments, a boundary has been established separating the paraffin area (the presence of paraffins as their solid phase) from an area without paraffin. Measurements of the amount of paraffin using the filter allowed the determination of the WPC (wax precipitation curve), due to which additional data is provided regarding the amount of precipitated paraffin deposit below the WAT. The developed methodology enables to conduct the measurements within a wide range of pressures using the sample saturated with reservoir gas, which can test the crude oil sample that corresponds to the actual production conditions. Most known research methods do not allow such preparation of a sample and conducting the measurements under pressurized conditions; therefore, the produced results are subject to errors. The paper describes also the studies of efficiency and differences in the action of various paraffin inhibitors. Based on the performed research, a comparison was made involving the action of agents under the pressureless conditions of dead oil and pressurized crude oil samples saturated with gas. The performed studies allowed the determination of equilibrium conditions (in a pressure–temperature system), under which deposition of the solid paraffin phase occurs during the use of three various inhibitors. Based on the performed experiments, an area with a paraffin hazard was determined, along with an area without paraffins. Due to the separation of the precipitated solid paraffin phase, an increase in the mass of the paraffin deposit associated with a temperature drop was determined (wax precipitation curve), as well as the impact of the applied inhibitors on its course.

scholarly journals An Interactive Method for Teaching Turbine Design

1999 ◽  
Author(s):  
K. W. Ramsden
Keyword(s):  
Gas Turbine ◽  
Teaching Method ◽  
New Technology ◽  
Worked Examples ◽  
Limited Range ◽  
Design Optimisation ◽  
Wide Range ◽  
And Performance ◽  
Turbine Design ◽  
The Impact

The implementation of new technology in the gas turbine industry is accelerating at a rate which demands increasing specialisation by its engineering design staff. Simultaneously, this industry has been adopting concurrent engineering practices to reduce product lead-time. Accordingly, the industry now requires its engineers to acquire competence in a wide range of technological disciplines together with a thorough understanding of the demands of design optimisation for the whole engine. Against this background, educational providers must respond to these increasing demands with teaching programmes that enable a more rapid and deeper understanding of a very complex product. The ambition of the teacher, however, to prepare the student will continue to be limited by time constraints within lecture courses. Hitherto, this has normally resulted in class worked examples which are necessarily narrow in scope and confined to a limited range of design cases. To overcome these limitations, a portfolio of multimedia computer programs has been developed specifically for rapid and relevant learning purposes. Each is structured to facilitate in-depth understanding of the key interactions between aerodynamics, thermodynamics and mechanical integrity needed in gas turbine design and performance assessment. This paper describes an interactive teaching method for turbine design optimisation using only the multimedia turbine design and performance module. Through the example of a case study, the preliminary design of a high pressure and low pressure turbine combination is undertaken initially by hand. This first pass design leaves substantial scope for design optimisation through a series of workshops using only the software. Final design recommendations are subsequently based on comprehensive tutor led but fully interactive discussion. Particular emphasis is placed on the impact of design decisions on both the various technology issues and on the performance of other engine components.

Effect of Trabecular Architecture on Transferring Load/Impact to the Brain: A Local Model of Single Trabecula

2011 ◽  
Author(s):  
Parisa Saboori ◽  
Ali Sadegh
Keyword(s):  
Subarachnoid Space ◽  
External Load ◽  
Animal Studies ◽  
Trabecular Architecture ◽  
Local Models ◽  
Pia Mater ◽  
The Impact ◽  
External Loads ◽  
The Brain ◽  
Load Impact

In this paper the mechanotransduction of the external load through the trabeculae in the subarachnoid space (SAS) was investigated. This has been accomplished by employing the results of our animal studies, i.e. the histology and architecture of trabeculae, and by creating local models consist of a trabecula. It is concluded that the trabeculae are mainly configured as an upright tree-like shaped, where the branches are attached to the pia mater and the stems are attached to the arachnoid. The result of the analysis reveal that said configuration of the trabeculae creates less strain in the brain when the head in subjected to external loads, and thereby damps the impact.

THE IMPACT OF LEADERSHIP PRACTICES TO TEAM MEMBERS’ SATISFACTION

2009 ◽  
Vol 8 (1) ◽  
Author(s):  
Chalimah .
Keyword(s):  
Conflict Resolution ◽  
Leadership Practices ◽  
Hotel Industry ◽  
Leader Behavior ◽  
Team Leader ◽  
Shop Floor ◽  
Team Members ◽  
Top Executives ◽  
Wide Range ◽  
The Impact

eamwork is becoming increasingly important to wide range of operations. It applies to all levels of the company. It is just as important for top executives as it is to middle management, supervisors and shop floor workers. Poor teamwork at any level or between levels can seriously damage organizational effectiveness. The focus of this paper was therefore to examine whether leadership practices consist of team leader behavior, conflict resolution style and openness in communication significantly influenced the team member’s satisfaction in hotel industry. Result indicates that team leader behavior and the conflict resolution style significantly influenced team member satisfaction. It was surprising that openness in communication did not affect significantly to the team members’ satisfaction.

IMPACT ASSESSMENT ON LEARNING MOTIVATION IN THE FRAMEWORK OF THE COMPETENCE APPROACH IN EDUCATION

2020 ◽  
Vol 22 (9) ◽  
pp. 28-34
Author(s):  
Huseynova А.А. ◽  
Vashchinnikova K.D.
Keyword(s):  
Design Method ◽  
Authentic Assessment ◽  
Educational Process ◽  
Learning Motivation ◽  
Assessment Process ◽  
Assessment Procedure ◽  
Positive Side ◽  
Educational Motivation ◽  
Educational Paradigm ◽  
The Impact

Turning to the new educational paradigm, the research paper considers the conditions for ensuring the effective-ness of authentic assessment of students ' achievements within the competence approach and the transition from traditional knowledge control to tests developed on the basis of the theory of pedagogical measurements. Special attention is paid to independent assessment as a tool for stimulating learning activities, as well as to the justifica-tion of the pattern design method used in the develop-ment of measurement tools. The experimental basis of the study is based on the results of an independent assess-ment of educational achievements of students of the sen-ior level of secondary vocational education in social studies in several educational organizations. As a result of the survey of participants in independent testing, the formation of a stable positive learning motivation is not-ed. The relationship with the assessment of the impact on educational motivation is confirmed by the respondents ' attitude to the authentic assessment procedure on the part of participants in the assessment process: school-children, teachers, and parents. As a result, it was re-vealed that all subjects of the educational process evalu-ate the impact of the proposed method of assessment on educational motivation from a positive side.

Stress, anxiety, depression and burnout in frontline health care workers during COVID-19 pandemic: a brief systematic review and new data from Russia

2021 ◽  
Author(s):  
Ekaterina Mosolova ◽  
Dmitry Sosin ◽  
Sergey Mosolov
Keyword(s):  
Risk Factors ◽  
Systematic Review ◽  
Female Gender ◽  
Assessment Tools ◽  
Care Workers ◽  
Younger Age ◽  
Wide Range ◽  
Associated Risk Factors ◽  
Anxiety Depression ◽  
The Impact

During the COVID-19 pandemic, healthcare workers (HCWs) have been subject to increased workload while also exposed to many psychosocial stressors. In a systematic review we analyze the impact that the pandemic has had on HCWs mental state and associated risk factors. Most studies reported high levels of depression and anxiety among HCWs worldwide, however, due to a wide range of assessment tools, cut-off scores, and number of frontline participants in the studies, results were difficult to compare. Our study is based on two online surveys of 2195 HCWs from different regions of Russia during spring and autumn epidemic outbreaks revealed the rates of anxiety, stress, depression, emotional exhaustion and depersonalization and perceived stress as 32.3%, 31.1%, 45.5%, 74.2%, 37.7% ,67.8%, respectively. Moreover, 2.4% of HCWs reported suicidal thoughts. The most common risk factors include: female gender, nurse as an occupation, younger age, working for over 6 months, chronic diseases, smoking, high working demands, lack of personal protective equipment, low salary, lack of social support, isolation from families, the fear of relatives getting infected. These results demonstrate the need for urgent supportive programs for HCWs fighting COVID-19 that fall into higher risk factors groups.

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