scholarly journals Determination of Cutting Forces in Grinding with Crossed Axes of Tool and Workpiece

2017 ◽  
Vol 11 (1) ◽  
pp. 58-63 ◽  
Author(s):  
Volodimyr Kalchenko ◽  
Andrij Yeroshenko ◽  
Sergiy Boyko ◽  
Nataliia Sira
Keyword(s):  
Cutting Forces ◽  
Processing System ◽  
Upper Limits ◽  
Local Point ◽  
Wide Range ◽  
Abrasive Surface ◽  
Crossed Axes ◽  
Contact Spots ◽  
Cutting Speeds

Abstract In the work the analysis of existent methods of determination of local and general forces of cutting at polishing of surfaces with a type as the arc of circumference is given. The dependence for determination of speed polishing and method for determination of thickness of the cut away layer on condition of equality of the tricked into and taken off volumes of material are offered. The method of determination of cutting forces, which takes into account cutting and deforming grain, is suggested. The method of determining the thickness of a cutting layer of one of the cutting edge, from the condition that the volume of material that is brought and is cut in each local point of contact spots has been proposed. The proposed method takes into account the compliance of the processing system and the discontinuity of the abrasive surface of the tool. By experimental way upper limits of thickness cutting layer when using different abrasive materials for a wide range of cutting speeds have been obtained.

scholarly journals Single motoneuron succinate dehydrogenase activity.

1989 ◽  
Vol 37 (7) ◽  
pp. 1107-1114 ◽  
Author(s):  
G R Chalmers ◽  
V R Edgerton
Keyword(s):  
Enzymatic Activity ◽  
Succinate Dehydrogenase ◽  
Time Course ◽  
Processing System ◽  
Enzyme Reaction ◽  
Histochemical Assay ◽  
Computer Image Processing ◽  
Wide Range ◽  
Soma Size

We have developed a quantitative histochemical assay for measurement of succinate dehydrogenase (SDH) activity in single motoneurons. A computer image processing system was used to quantify the histochemical enzyme reaction product and to follow the time course of the reaction. The optimal concentration for each of the ingredients of the incubation medium for the SDH reaction was determined and the importance of using histochemical "blanks" in the determination of enzymatic activity was demonstrated. The enzymatic activity was linear with respect to reaction time and tissue thickness. The procedure described meets the criteria generally considered essential for establishment of a quantitative histochemical assay. The assay was then used to examine the SDH activity of cat and rat motoneurons. It was found that motoneurons with a small soma size had a wide range of SDH activity, whereas those with a large soma size were restricted to low SDH activity.

scholarly journals The upper limits of the continuous β-ray spectra of thorium C and C″

1934 ◽  
Vol 147 (862) ◽  
pp. 572-582 ◽  
Keyword(s):  
Accurate Determination ◽  
Simple Relation ◽  
Maximum Energy ◽  
Energy Limit ◽  
Expansion Chamber ◽  
End Point ◽  
Upper Limits ◽  
Wide Range ◽  
Magnetic Analysis

It is well known that the disintegration electrons from a radioactive body are distributed over a wide range of velocities, and that a characteristic feature of this distribution is that there is an upper energy limit above which no electrons are emitted. The accurate determination of these upper limits and the corresponding maximum energy of the β-rays has become of much importance in connection with special theories which have been advanced to explain the nature of the β-ray disintegration. Numerous experiments have been done to find these upper limits or end points. Most of the existing data are based on range measurements in which the energy of the fastest β-rays from a source is deduced from their range. The chief advantage of the method is that it can be carried out with weak or rapidly decaying sources; the great disadvantage is that owing to the scattering suffered by the β-particles, the range found by experiment is an indefinite quantity and has no simple relation to the maximum energy of the β-particles. Because of this fact range methods, while frequently giving results in general agreement with magnetic analysis, are not capable of leading to accurate results for the upper limits. There remain two other methods of analysis, the magnetic spectrograph and the expansion chamber. The latter as used by Terroux and Alexander gives a higher upper limit than other methods. For radium E Terroux reported a tail extending to 3,000,000 volts, while other methods give an end point at about 1,070,000 volts. Champion, in repeating Terroux’s experiments, emphasized the precautions that must be taken in interpreting the experimental material. To eliminate the effect of scattering he was forced to adopt a criterion that a particle would be counted only if it had an undisturbed track greater than a certain length. The cloud-chamber method, while applicable to very weak sources, must be used with great care, and cannot give an accurate value of the end point without taking a very large number of photographs.

Experimental and Numerical Investigation of the Influence of Cutting Speed and Feed Rate on Forces in Turning of Steel

2016 ◽  
Vol 862 ◽  
pp. 270-277 ◽  
Author(s):  
János Kundrák ◽  
Gergely Szabó ◽  
Angelos P. Markopoulos
Keyword(s):  
Finite Elements ◽  
Feed Rate ◽  
Cutting Speed ◽  
Cutting Conditions ◽  
Strain Rates ◽  
Wide Range ◽  
Speed Range ◽  
The Impact ◽  
Cutting Speeds

The impact of cutting speeds and feed rates on the components of the forces exerted on a 16MnCr5 steel workpiece is experimentally measured, when turning with PCBN tool. The cutting speed range of the tests varies between 90 to 240 m/min while the feed rate is between 0.05 and 0.25 mm/rev for each cutting speed, allowing for the determination of the influence of cutting conditions on forces. Additionally, finite elements models for the simulation of the aforementioned experiments are provided. The proposed models exhibit good correlation of their results on cutting forces and chip formation with the measurements and observations of the experiments. Furthermore, the models can provide a wide range of additional parameters, i.e. plastic strain rates and temperatures within the workpiece. Results of the presented analysis can be used for an efficient process planning for the turning of steels under cutting conditions used in the industry.

MODELING OF THE GRINDING PROCESS BY MICRO-CUTTING SINGLE ABRASIVE GRAINS. PART 1. DETERMINATION OF THE STRENGTH OF ABRASIVE GRAINS

2020 ◽  
pp. 13-17
Author(s):  
Yu. M. Zubarev ◽  
A. V. Priemyshev
Keyword(s):  
Cutting Speed ◽  
Tool Material ◽  
Physical And Mechanical Properties ◽  
Workpiece Material ◽  
Micro Cutting ◽  
Abrasive Grains ◽  
Maximum Cut ◽  
Wide Range ◽  
Cutting Speeds

Main performance indicators of grinding wheels are the strength and wear resistance of abrasive grains. The description of the installation for studying the process of micro-cutting of various materials with single abrasive grains, which allows you to approximate the working conditions of a single abrasive grain to the conditions of real grinding in a wide range of cutting speeds. The effect of the cutting speed on the maximum cut thickness maintained by the grain vertexes without their destruction is shown. The influence of physical and mechanical properties of the workpiece material and the abrasive tool material, together with technological factors, on the micro-cutting process is considered.

Determination of the Temperature of a Machined Surface

1998 ◽  
Vol 120 (2) ◽  
pp. 259-263 ◽  
Author(s):  
T. H. Chu ◽  
J. Wallbank
Keyword(s):  
Mild Steel ◽  
Cutting Forces ◽  
Cutting Speed ◽  
Cutting Edge ◽  
Depth Of Cut ◽  
Constant Depth ◽  
Nose Radius ◽  
Machined Surface ◽  
Cutting Speeds

A technique for measuring temperature close to the primary cutting edge in turning has been developed. The cutting temperatures of a 0.16 percent carbon bright drawn mild steel, have been measured for a range of cutting speeds and feedrates at a constant depth of cut. Tool nose radius was also varied. The correlations for the workpiece temperature of cutting speed and feedrate have been developed. The results show that the temperature correlates well with cutting speed and feedrate but the nose radius has little effect. Cutting forces were measured by a dynamometer and these were used to find the non zero forces at zero feedrate. These forces have been related to the deformation of the work material near the cutting edge of the tool and a method for calculating the cutting temperatures from these has been proposed.

scholarly journals Determination of the Intrinsic Scatter in the MBH–σ and MBH–Lbulge Relations

2009 ◽  
Vol 5 (S267) ◽  
pp. 189-194
Author(s):  
Kayhan Gültekin
Keyword(s):  
Black Hole ◽  
Measurement Errors ◽  
Mass Function ◽  
Host Galaxy ◽  
Black Hole Mass ◽  
Upper Limits ◽  
Wide Range ◽  
Sphere Of Influence ◽  
Intrinsic Scatter

AbstractWe derive improved versions of the relations between supermassive black hole mass MBH and host-galaxy bulge velocity dispersion σ and luminosity L (the MBH–σ and MBH–Lbulge relations), based on ~ 50 MBH measurements and ~ 20 upper limits. Particular attention is paid to recovery of the intrinsic scatter (ϵ0) in both relations. We find the scatter to be significantly larger than estimated in most previous studies. The large scatter requires revision of the local black hole mass function, and it implies that there may be substantial selection bias in studies of the evolution of the MBH–σ and MBH–Lbulge relations. When only considering ellipticals, the scatter decreases. These results appear to be insensitive to a wide range of assumptions about the measurement errors and the distribution of intrinsic scatter. We also investigate the effects on the fits of culling the sample according to the resolution of the black hole's sphere of influence.

DINAMIKA POLITIK PERSETUJUAN BERSAMA TENTANG PENETAPAN DESA ADAT DI KABUPATEN ROKAN HULU TAHUN 2014

2017 ◽  
Vol 15 (1) ◽  
pp. 21
Author(s):  
Haryo Suganda ◽  
Raja Muhammad Amin
Keyword(s):  
Regulatory Region ◽  
Field Research ◽  
Analysis Techniques ◽  
Political Dynamics ◽  
Political Interests ◽  
Wide Range ◽  
Information Method ◽  
Qualitative Descriptive ◽  
The Village

This study is motivated the identification of policies issued by the regional Governmentof Rokan Hulu in the form of Regulatory region number 1 by 2015 on the determination of thevillage and Indigenous Village. Political dynamics based on various interests against themanufacture of, and decision-making in the process of formation of the corresponding localregulations determination of Indigenous Villages in the Rokan Hulu is impacted to a verysignificantamount of changes from the initial draft of the number i.e. 21 (twenty one) the villagebecame Customary 89 (eighty-nine) the Indigenous Villages who have passed. Type of thisresearch is a qualitative descriptive data analysis techniques. The research aims to describe theState of the real situation in a systematic and accurate fact analysis unit or related research, aswell as observations of the field based on the data (information). Method of data collectionwas done with interviews, documentation, and observations through fieldwork (field research).The results of the research on the process of discussion of the draft local regulations andmutual agreement about Designation of Indigenous Villages in the Rokan Hulu is, showed thatthe political dynamics that occur due to the presence of various political interests, rejectionorally by Villagers who were judged to have met the requirements of Draft Regulations to beformulated and the area for the set to be Indigenous Villages, and also there is a desire fromsome villages in the yet to Draft local regulations in order to set the Indigenous village , there isa wide range of interests of these aspects influenced the agreement to assign the entire localVillage which is in the Rokan Hulu become Indigenous village, and the village of Transmigrationinto administrative Villages where the initiator of the changes in the number of IndigenousVillages in the Rokan Hulu it is the desire of the local Government of its own.

EXPRESS: Method dependent variation in TSH and FT4 reference intervals in pregnancy: a systematic review

2021 ◽  
pp. 000456322110269
Author(s):  
O E Okosieme ◽  
Medha Agrawal ◽  
Danyal Usman ◽  
Carol Evans
Keyword(s):  
Systematic Review ◽  
Reference Interval ◽  
First Trimester ◽  
Reference Intervals ◽  
Assay Method ◽  
Specific Reference ◽  
Upper Limits ◽  
Wide Range ◽  
Assay Methods ◽  
In Pregnancy

Background: Gestational TSH and FT4 reference intervals may differ according to assay method but the extent of variation is unclear and has not been systematically evaluated. We conducted a systematic review of published studies on TSH and FT4 reference intervals in pregnancy. Our aim was to quantify method-related differences in gestation reference intervals, across four commonly used assay methods, Abbott, Beckman, Roche, and Siemens. Methods: We searched the literature for relevant studies, published between January 2000 and December 2020, in healthy pregnant women without thyroid antibodies or disease. For each study, we extracted trimester-specific reference intervals (2.5–97.5 percentiles) for TSH and FT4 as well as the manufacturer provided reference interval for the corresponding non-pregnant population. Results: TSH reference intervals showed a wide range of study-to-study differences with upper limits ranging from 2.33 to 8.30 mU/L. FT4 lower limits ranged from 4.40–13.93 pmol/L, with consistently lower reference intervals observed with the Beckman method. Differences between non-pregnant and first trimester reference intervals were highly variable, and for most studies the TSH upper limit in the first trimester could not be predicted or extrapolated from non-pregnant values. Conclusions: Our study confirms significant intra and inter-method disparities in gestational thyroid hormone reference intervals. The relationship between pregnant and non-pregnant values is inconsistent and does not support the existing practice in some laboratories of extrapolating gestation references from non-pregnant values. Laboratories should invest in deriving method-specific gestation reference intervals for their population.

scholarly journals Recent Developments in the Determination of Biomarkers of Tobacco Smoke Exposure in Biological Specimens: A Review

2021 ◽  
Vol 18 (4) ◽  
pp. 1768
Author(s):  
Hernâni Marques ◽  
Pedro Cruz-Vicente ◽  
Tiago Rosado ◽  
Mário Barroso ◽  
Luís A. Passarinha ◽  
...  
Keyword(s):  
Tobacco Smoke ◽  
Solid Phase ◽  
Smoke Exposure ◽  
Tobacco Smoke Exposure ◽  
World Health ◽  
Second Hand Smoke ◽  
Tobacco Exposure ◽  
Wide Range ◽  
Recent Developments

Environmental tobacco smoke exposure (ETS) and smoking have been described as the most prevalent factors in the development of certain diseases worldwide. According to the World Health Organization, more than 8 million people die every year due to exposure to tobacco, around 7 million due to direct ETS and the remaining due to exposure to second-hand smoke. Both active and second-hand exposure can be measured and controlled using specific biomarkers of tobacco and its derivatives, allowing the development of more efficient public health policies. Exposure to these compounds can be measured using different methods (involving for instance liquid- or gas-chromatographic procedures) in a wide range of biological specimens to estimate the type and degree of tobacco exposure. In recent years, a lot of research has been carried out using different extraction methods and different analytical equipment; this way, liquid–liquid extraction, solid-phase extraction or even miniaturized procedures have been used, followed by chromatographic analysis coupled mainly to mass spectrometric detection. Through this type of methodologies, second-hand smokers can be distinguished from active smokers, and this is also valid for e-cigarettes and vapers, among others, using their specific biomarkers. This review will focus on recent developments in the determination of tobacco smoke biomarkers, including nicotine and other tobacco alkaloids, specific nitrosamines, polycyclic aromatic hydrocarbons, etc. The methods for their detection will be discussed in detail, as well as the potential use of threshold values to distinguish between types of exposure.

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