scholarly journals Modeling Process of Forming Flat Surface Tool for Processing Conical Parts

2020 ◽  
Vol 19 (6) ◽  
pp. 492-498
Author(s):  
A. S. Kozeruk ◽  
R. O. Dias Gonzalez ◽  
M. I. Filonova
Keyword(s):  
Contact Zone ◽  
Flat Surface ◽  
The Body ◽  
Work Piece ◽  
Second Stage ◽  
Modeling Process ◽  
Working Surface ◽  
Processed Material ◽  
Processing Modes ◽  
External Conditions

The relative actuation of the tool is considered, which makes it possible not to take into account the hard-to-determine technological coefficients depending on external conditions, as well as the physical, mechanical and technological properties of the processed material. This response is determined by the distribution of the relative sliding speeds and pressure in the contact zone of the tool and the work-piece, as well as the processing time, which are characterized by the geometric and kinematic parameters of the machine operating mechanism and processing modes. A phased simulation of the actuation process of the tool working surface is proposed: without oscillation of  the upper link and with its return-rotational  movement. According to this approach, at the first stage, the distribution of the relative sliding speeds and pressure in the contact zone of the grinding surfaces is calculated, and at the second stage, when determining the relative response at the points of the lower link (tool), the movement of these points from the areas of the contact zone with same values of the indicated quantities in the area with others is monitored. A mathematical model of the process of shaping a flat surface under conditions of free grinding of the body and counter-body is obtained, which establishes quantitative relationships between the machining modes and the shape of the treated surface and is a simulation numerical model, since it allows to obtain the distribution of relative triggering over the working surface of the tool for pre-selected time points.

scholarly journals Modeling of thermal processes in the contact zones of fuel elements

2021 ◽  
pp. 83-92
Author(s):  
Vladimir Kondratenko ◽  
Victor Kadomkin ◽  
Olga Tretiyakova
Keyword(s):  
Contact Zone ◽  
Operating Conditions ◽  
Thermal Processes ◽  
Thermal Interface ◽  
Contact Zones ◽  
Processed Material ◽  
Processing Modes ◽  
Technological Processing ◽  
Diamond Grain ◽  
Fuel Elements

In this work, using two specific examples, a general approach to the mathematical modeling of thermal processes in the contact zones of fuel elements in the development and optimization of various technological processes, systems and devices is considered. In the first example, a mathematical model of heat transfer in the contact zone (metal-hybrid thermal interface) between the heat-generating element and the heat-dissipating radiator is considered. In the second case, the thermal process in the processing of materials with a bonded diamond tool in the contact zone "diamond grain – binder – processed material" is considered and analyzed. The general approach to modeling thermal processes in the contact zones of various fuel elements makes it possible to optimize the parameters of technological processing modes and the correct operating conditions for products and systems

‘She Sleeps Well and Eats an Egg’

2018 ◽  
Author(s):  
Hannah Newton
Keyword(s):  
Life Style ◽  
The Body ◽  
Serious Illness ◽  
Second Stage ◽  
Full Strength ◽  
Central Argument

Serious illness often left the body weak and lean, full of the ‘footsteps of disease’; it wasn’t until full strength and flesh had returned that the patient was pronounced back to health. This chapter explores the second stage of recovery in contemporary perceptions, the restoration of strength, or ‘convalescence’. It asks how the patient’s growing strength was measured and promoted, and unveils a concept of convalescent care, ‘analeptics’. The central argument is that both the mechanisms and the measures for the restoration of strength were intimately connected to the ‘non-natural things’, six dietary and life-style factors. The opening sections explain why the body was weak after illness, and categorize the convalescent within contemporary schemes of health. The rest of the chapter is structured around the signs of increasing strength, each of which was associated with a particular non-natural: ‘the final purge’, ‘sleeping through the night’, ‘feeling hungry’, ‘growing cheerful’, and ‘sitting up to going abroad’.

Benchmarking the efficiencies of Indonesia’s municipal water utilities using Stackelberg data envelopment analysis

2015 ◽  
Vol 22 (4) ◽  
pp. 588-609 ◽  
Author(s):  
Andreas Wibowo ◽  
Hans Wilhelm Alfen
Keyword(s):  
Data Envelopment Analysis ◽  
The Body ◽  
Water Utilities ◽  
Data Envelopment ◽  
Two Stage ◽  
Restrictive Assumption ◽  
Content Type ◽  
Second Stage ◽  
Municipal Water ◽  
The Impact

Purpose – The purpose of this paper is to present a yardstick efficiency comparison of 269 Indonesian municipal water utilities (MWUs) and measures the impact of exogenous environmental variables on efficiency scores. Design/methodology/approach – Two-stage Stackelberg leader-follower data envelopment analysis (DEA) and artificial neural networks (ANN) were employed. Findings – Given that serviceability was treated as the leader and profitability as the follower, the first and second stage DEA scores were 55 and 32 percent (0 percent = totally inefficient, 100 percent = perfectly efficient), respectively. This indicates sizeable opportunities for improvement, with 39 percent of the total sample facing serious problems in both first- and second-stage efficiencies. When profitability instead leads serviceability, this results in more decreased efficiency. The size of the population served was the most important exogenous environmental variable affecting DEA efficiency scores in both the first and second stages. Research limitations/implications – The present study was limited by the overly restrictive assumption that all MWUs operate at a constant-return-to-scale. Practical implications – These research findings will enable better management of the MWUs in question, allowing their current level of performance to be objectively compared with that of their peers, both in terms of scale and area of operation. These findings will also help the government prioritize assistance measures for MWUs that are suffering from acute performance gaps, and to devise a strategic national plan to revitalize Indonesia’s water sector. Originality/value – This paper enriches the body of knowledge by filling in knowledge gaps relating to benchmarking in Indonesia’s water industry, as well as in the application of ensemble two-stage DEA and ANN, which are still rare in the literature.

scholarly journals Investigation of performance properties of rubber with metal fillers

2021 ◽  
pp. 20-23
Author(s):  
S. V. Pashukevich ◽  
Keyword(s):  
Wear Resistance ◽  
Service Life ◽  
Contact Zone ◽  
Laboratory Tests ◽  
The Body ◽  
Body Of Revolution ◽  
Hydraulic Systems ◽  
Rubber Mixture ◽  
Fine Powders ◽  
Positive Results

The work conducts laboratory tests on the rubber of the first group of GOST 8752-70 with the introduction of the metal components. The filler is introduced into the rubber mixture on laboratory rollers. Fine powders of copper (Cu), tin (Sn) and lead (Pb) are used as fillers. The dependences of the temperature in the contact zone of the sample and the body of revolution on the concentration of the filler and the dependence of wear on the concentration of the filler for the same loads and sliding speeds are obtained, the fillers that give the rubber the greatest wear resistance are revealed, and the rational amount of the filler is determined. The positive results of laboratory tests give grounds to recommend various equipment including aerospace equipment for use in sealing devices of hydraulic systems, rubber products with metal fillers in the indicated concentrations, which will extend their service life and increase their reliability

scholarly journals THE INFLUENCE OF THE SHAPE OF WORKING SURFACE OF STRAIGHTENING ROLLERS OF VERTICAL AND HORIZONTAL STRAIGHTENING MACHINES ON THE STATE OF RESIDUAL STRESSES IN RAILWAY RAIL – SECOND STAGE OF RESEARCHES

2020 ◽  
Vol 72 (1) ◽  
pp. 48-58
Keyword(s):  
Residual Stresses ◽  
Symmetry Axis ◽  
The State ◽  
Roll Pass ◽  
Distribution Maps ◽  
Second Stage ◽  
Working Surface ◽  
National Centre ◽  
Railway Rail

The paper presents the results of the second stage of work on the influence of the shape of straightening rollers on the state of residual stresses in rails, conducted as part of a project co-financed by the National Centre for Research and Development. The tests included numerical simulations of the rail straightening process using a new roll pass design of vertical and horizontal straightener rollers, determination of stress distribution maps in the rail after straightening in successive rollers of both straightening machines, as well as measurement of residual stresses in the rails after straightening operation in industrial conditions. The tests were carried out on R260 grade 60E1 rails. The reduction of tensile residual stresses in the centre of symmetry axis of the rail foot was obtained up to an average level of 32 MPa, i.e. by more than four times less in relation to the level achieved using traditional technology.

scholarly journals Peroxidase Activity of Human Hemoproteins: Keeping the Fire under Control

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2561 ◽  
Author(s):  
Irina Vlasova
Keyword(s):  
Hydrogen Peroxide ◽  
Peroxidase Activity ◽  
Biological Effects ◽  
Reactive Intermediates ◽  
The Body ◽  
Main Function ◽  
Hypohalous Acids ◽  
Tyrosyl Radicals ◽  
External Conditions ◽  
Structure Properties

The heme in the active center of peroxidases reacts with hydrogen peroxide to form highly reactive intermediates, which then oxidize simple substances called peroxidase substrates. Human peroxidases can be divided into two groups: (1) True peroxidases are enzymes whose main function is to generate free radicals in the peroxidase cycle and (pseudo)hypohalous acids in the halogenation cycle. The major true peroxidases are myeloperoxidase, eosinophil peroxidase and lactoperoxidase. (2) Pseudo-peroxidases perform various important functions in the body, but under the influence of external conditions they can display peroxidase-like activity. As oxidative intermediates, these peroxidases produce not only active heme compounds, but also protein-based tyrosyl radicals. Hemoglobin, myoglobin, cytochrome c/cardiolipin complexes and cytoglobin are considered as pseudo-peroxidases. Рeroxidases play an important role in innate immunity and in a number of physiologically important processes like apoptosis and cell signaling. Unfavorable excessive peroxidase activity is implicated in oxidative damage of cells and tissues, thereby initiating the variety of human diseases. Hence, regulation of peroxidase activity is of considerable importance. Since peroxidases differ in structure, properties and location, the mechanisms controlling peroxidase activity and the biological effects of peroxidase products are specific for each hemoprotein. This review summarizes the knowledge about the properties, activities, regulations and biological effects of true and pseudo-peroxidases in order to better understand the mechanisms underlying beneficial and adverse effects of this class of enzymes.

Coordinated righting behaviour in locusts

2001 ◽  
Vol 204 (4) ◽  
pp. 637-648 ◽  
Author(s):  
A.A. Faisal ◽  
T. Matheson
Keyword(s):  
Driving Force ◽  
Flat Surface ◽  
Longitudinal Axis ◽  
Upright Position ◽  
The Body ◽  
The Other ◽  
Legged Robots ◽  
Naturally Occurring ◽  
Key Features ◽  
Low Levels

A locust placed upside down on a flat surface uses a predictable sequence of leg movements to right itself. To analyse this behaviour, we made use of a naturally occurring state of quiescence (thanatosis) to position locusts in a standardised upside-down position from which they spontaneously right themselves. Locusts grasped around the pronotum enter a state of thanatosis during which the limbs can be manipulated into particular postures, where they remain, and the animal can be placed upside down on the ground. When released, thanatosis lasts 4–456 s (mean 73 s) before the animal suddenly becomes active again and rights itself within a further 600 ms. Thanatosis is characterised by very low levels of leg motor activity. During righting, one hind leg provides most of the downward force against the ground that rolls the body around a longitudinal axis towards the other side. The driving force is produced by femoral levation (relative to the body) at the trochanter and by tibial extension. As the animal rolls over, the hind leg on the other side is also levated at the trochanter, so that it does not obstruct the movement. The forelegs and middle legs are not required for successful righting but they can help initially to tip the locust to one side, and at the end of the movement they help stop the roll as the animal turns upright. Individual locusts have a preferred righting direction but can, nevertheless, roll to either side. Locusts falling upside down through the air use both passive and active mechanisms to right themselves before they land. Without active movements, falling locusts tend to rotate into an upright position, but most locusts extend their hind leg tibiae and/or spread their wings, which increases the success of mid-air righting from 28 to 49 % when falling from 30 cm. The rapid and reliable righting behaviour of locusts reduces the time spent in a vulnerable upside-down position. Their narrow body geometry, large hind legs, which can generate substantial dorsally directed force, and the particular patterns of coordinated movements of the legs on both sides of the body are the key features that permit locusts to right themselves effectively. The reliability of autonomous multi-legged robots may be enhanced by incorporating these features into their design.

Terapi Mandi Terhadap Pecandu Narkotika Di Pondok Pesantren Al-Qodir Cangkringan Sleman Yogyakarta

2020 ◽  
Vol 1 (2) ◽  
pp. 1
Author(s):  
Muslimah Muslimah
Keyword(s):  
Qualitative Research ◽  
Descriptive Analysis ◽  
Boarding School ◽  
The Body ◽  
Second Stage ◽  
The Third ◽  
Third Stage ◽  
Preparation Stage ◽  
Qualitative Descriptive ◽  
Bath Therapy

This study aims to determine how the process and benefits of bath therapy for narcotic addicts at Al-Qodir Islamic Boarding School, Cangkringan, Sleman Yogyakarta. This research is a qualitative research with two clients who undergo healing due to narcotics addiction. Methods of data collection by interview, observation, documentation. The method of checking the validity of the data used the "triangulation" technique. Data analysis using qualitative descriptive analysis. The results of this study describe that the process of bathing therapy carried out by narcotic addicts at the Al-Qodir Islamic boarding school goes through several stages. The first is the preparation stage, namely the therapist preparing the facilities, waking the narcotic addicts santri, and reading prayers into the bathroom. The second stage of implementation is the intention to bathe, perform ablution, and pour water all over the body. The third stage of closing is reading the prayer out of the bathroom, and giving suggestions from the therapist. Abstrak Penelitian ini bertujuan untuk mengetahui bagaimana proses dan manfaat terapi mandi terhadap pecandu narkotika di Pondok Pesantren Al-Qodir Cangkringan Sleman Yogyakarta. Penelitian ini merupakan penelitian kualitatif dengan subjek penelitian dua orang klien yang menjalani penyembuhan akibat pecandu narkotika. Metode  pengumpulan data dengan wawancara, observasi, dokumentasi. Metode pemeriksaan keabsahan data dengan tehnik “triangulasi”. Analisis data menggunakan analisis deskriptif kualitatif. Hasil penelitian ini mendeskripsikan bahwa proses terapi mandi yang dilakukan oleh para santri pecandu narkotika di pondok pesantren Al-Qodir ini melalui beberapa tahapan. Pertama tahap persiapan yaitu terapis menyiapkan sarana, membangunkan para santri pecandu narkotika, dan membaca do’a masuk kamar mandi. Tahap kedua pelaksanaan yaitu niat mandi, berwudhu, menyiramkan air ke seluruh tubuh. Tahap ketiga penutupan yaitu membaca do’a keluar kamar mandi, dan memberikan sugesti dari terapis.

Modal Analysis as a Means of Researching the Vibrations in Grinding

2015 ◽  
Vol 756 ◽  
pp. 15-18
Author(s):  
Dmitrii V. Ardashev
Keyword(s):  
Close Correlation ◽  
Operating Conditions ◽  
Grinding Wheel ◽  
Sufficient Information ◽  
Main Role ◽  
Wheel Wear ◽  
Grinding Wheel Wear ◽  
Working Surface ◽  
Processed Material ◽  
General Scale

During the grinding process the main role is played by the vibrating phenomena caused by primary imbalance of a wheel, features of its structure, and also the existence of a component arising in the general scale of vibrations and caused by the change of the structure of a working surface of a grinding wheel, wear of its working abrasive grains during the process. Intensity and amount of wear of the grinding wheel depends on conditions of grinding operation – kind of grinding, processed material, etc. In turn, the existence of close correlation connection between parameters of vibrations and modes of grinding allows to assume, that vibrating processes possess sufficient information and can form the basis for an assessment and forecast the perfection factor of a grinding wheel directly in operating conditions.

scholarly journals Oblique impact of a smooth body on a thin layer of inviscid liquid

2013 ◽  
Vol 469 (2151) ◽  
pp. 20120615 ◽  
Author(s):  
T. I. Khabakhpasheva ◽  
A. A. Korobkin
Keyword(s):  
Body Surface ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Hydrodynamic Pressure ◽  
Oblique Impact ◽  
The Body ◽  
Second Stage ◽  
Smooth Body ◽  
Vertical Displacements ◽  
The Impact

The two-dimensional motion of a rigid body with a smooth surface is studied during its oblique impact on a liquid layer. The problem is coupled: the three degrees of freedom of the moving body are determined together with the liquid flow and the hydrodynamic pressure along the wetted part of the body surface. The impact process is divided into two temporal stages. During the first stage, the wetted region expands at a high speed with jetting flows at both ends of the wetted region. In the second stage, the free surface of the liquid is allowed to separate from the body surface. The position of the separation point is determined with the help of the Brillouin–Villat condition. Calculations are performed for elliptic cylinders of different masses and with different orientations and speeds before the impact. The horizontal and vertical displacements of the body, as well as its angle of rotation and corresponding speeds are investigated. The model developed remains valid until the body either touches the bottom of the liquid or rebounds from the liquid.

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