scholarly journals Substantiation of the Density of the Soil Formed by a Ridge Drill Roller

2021 ◽  
pp. 14-16
Author(s):  
E.S. Zykin ◽  
◽  
V.I. Kurdyumov ◽  
S.A. Lazutkina ◽  
S.P. Albutov ◽  
...  
Keyword(s):  
Angle Of Attack ◽  
Technical Analysis ◽  
Simultaneous Action ◽  
Compression Force ◽  
Conical Roller

A method is presented for determining the density of soil in the ridge from the simultaneous action of spherical disks and a conical roller wheel. Heuristic and technical analysis of the process of forming soil ridges by rollers made it possible to conclude with a 90 % reliability that the main factorsб which significantly affect the quality of soil ridge formation, are the angle of attack of spherical discs (α = 10°), the speed of the roller (vс = 5.4 km / h) and the compression force of its spring (Fspr. = 180 N).

Study on Mechanism of Molybdenum Concentrate Carbon-Free Roasting

2012 ◽  
Vol 588-589 ◽  
pp. 1685-1688 ◽  
Author(s):  
Lian Yong Wang ◽  
Jing Fan Zhang ◽  
Lei Dai ◽  
Jiu Ju Cai
Keyword(s):  
Technical Analysis ◽  
Economic Benefits ◽  
Thermal Balance ◽  
Environmental Benefits ◽  
Heat Of Reaction ◽  
Balance Test ◽  
Operating Process ◽  
Output Quality ◽  
Molybdenum Concentrate

Technical analysis was used to analyze the roasting of molybdenum concentrate on the basis of thermal balance test of rotary furnaces used for Roasting, and the results indicate that, on the condition of commercial production, the Roasting of MoS2 can occur spontaneously because the heat of reaction is so much that proper cooling measures should be adopted in case overheating happens. According to above analysis, carbon-free roasting technology of molybdenum concentrate was proposed in this paper. The results, which come from thermal balance test and technical analysis of rotary furnaces used for carbon-free roasting of molybdenum concentrate, indicate that outer heat source used in traditional Roasting technology is not needed in carbon-free roasting technology, because enough heat is generated during Roasting to ensure spontaneous reaction. In fact, heating is not needed in operating process except at the beginning, to make molybdenum concentrate catching fire, and when reaction completing, to remove residual sulphur. The technology in this paper is obviously advantageous in aspects of energy saving, output, quality of production, heat loss, the concentration of SO2 in flue gas, etc. and will have remarkable environmental benefits, economic benefits and social benefits.

scholarly journals Mechanical behavior of pumpkin fruits subjected to compression during maturation

2013 ◽  
Vol 43 (3) ◽  
pp. 223-231 ◽  
Author(s):  
Acácio Figueiredo Neto ◽  
Francisco de Assis Cardoso Almeida ◽  
Nelson Cárdenas Olivier ◽  
Alan Christie Silva Dantas ◽  
Marcos Antonio Silva Irmão
Keyword(s):  
Deformation Modulus ◽  
Maximum Load ◽  
Maximum Force ◽  
Parallel Plates ◽  
Compression Force ◽  
Production Chain ◽  
Maximum Deformation ◽  
Deformability Modulus ◽  
The Ideal

During handling operations, many problems that reduce the quality of vegetables may occur. Mechanical injuries are the leading cause of postharvest losses for the pumpkin, and can take place at any point of the production chain. This study aimed at evaluating the pumpkin fruits behavior, during their ripening stages, on the values of maximum compression force for fixed deformations, and determining the proportional deformability modulus of the fruits under compression at the repose position. Fruits were harvested at 15, 30, 40, 50 and 60 days after flowering and uniaxially compressed between two parallel plates. The results allowed to conclude that both the required compression force and the proportional deformability modulus increased during the maturation course, reaching a maximum force of 1,778 N and a maximum deformation modulus of 164 MPa, after 30 days. After this period, both the maximum force and the modulus values decreased, reaching 1,514.8 N of maximum force and a modulus of 132.09 MPa, after 60 days of ripening. Over the course of a longer maturation time, the fruit firmness increased, therefore requiring an increase in the maximum load to achieve greater deformation. The ideal period for harvest and transport of 'Jacarezinho' pumpkin fruits was set from 30 to 40 days after anthesis.

Study and Build-Up of Deformation Zone at Cutting of Thin-Walled Tube by Torsion

2017 ◽  
Vol 746 ◽  
pp. 16-21
Author(s):  
S.G. Simagina
Keyword(s):  
Deformation Zone ◽  
Heating Temperature ◽  
Compression Force ◽  
Angular Deflection ◽  
Thin Walled Tube ◽  
Temperature Impact ◽  
Thin Walled ◽  
Force Range ◽  
Intensive Development

Intensive development of Russian aviation and aerospace industries put an emphasis to the problem of quality of using materials and workpieces and to the value of technical and economical indexes in the context of planned production level [1, 2]. Waste-free technologies are preferred. Cutting by torsion or cutting by shear are preferable technologies if thin-walled tube cutting is the main blanking operation. Build-up of workpiece deformation zone plays an important role in the cutting process. Deformation zone determines stability of details during further processing and exploitation. An extended research was conducted about tube separation process using torsion with an active counterpressure. Some parameters was defined in the result of research, in particular: distribution of deformation zone along length and thickness of workpiece, angular deflection and compression force and workpiece heating temperature impact on build-up of whisker disposition in the cut zone. It allows identifying optimum compression force range and temperature conditions. Compliance with recommended practices allows conducting thin-walled tube separation simultaneously with build-up on the workpieces whisker structure that is fortunate for further pressure treatment and exploitation.

An Efficient Scheme for Describing Airfoils Using Non-Uniform Rational B-Splines

2012 ◽  
Author(s):  
Francois J. L. Wessels ◽  
G. Venter ◽  
T. W. Von Backström
Keyword(s):  
Wind Turbine ◽  
Numerical Optimization ◽  
Angle Of Attack ◽  
Optimization Process ◽  
B Splines ◽  
Design Project ◽  
Numerical Design ◽  
Efficient Scheme ◽  
Optimization Efficiency

In the well developed field of airfoil design there are a number of established schemes for describing airfoils, each with its own limitations and suitability to a particular application. Although less parsimonious, B-splines are often used to find solutions unconstrained by the characteristics of these schemes. They have proven useful to improve on existing designs and are useful in a numerical optimization process. As part of a numerical design project of a small wind turbine, a parametric scheme using Non-Uniform Rational B-Splines (NURBS) offering intuitive control over airfoil shape and unambiguous definitions for chord length and angle of attack is needed. These features are achieved at the lowest number of variables possible to ensure numerical optimization efficiency. Two previously uninvestigated NURBS arrangements are defined and investigated. The quality of the resulting airfoil reproductions are geometrically and aero-dynamically investigated and based on the results, the use of a thickness-camber scheme is motivated.

scholarly journals Analysis of technical parameters of black coals used in low–power boilers

2018 ◽  
Vol 19 (12) ◽  
pp. 386-389
Author(s):  
Bartosz Ciupek ◽  
Rafał Urbaniak ◽  
Karolina Perz
Keyword(s):  
Low Power ◽  
Thermodynamic Parameters ◽  
Technical Analysis ◽  
Thermal Processes ◽  
Emission Standard ◽  
Technical Aspects ◽  
Technical Parameters ◽  
Comprehensive List ◽  
Current State

The article presents the results of technical analysis of black coals available in retail sales in Poland. A comprehensive list of fuel technical parameters and analysis of the possibilities of their use in low-power boilers was supported by the experience of the authors of the study. A thorough analysis of technical parameters of fuels concerned basic thermodynamic parameters of fuels responsible for the quality of thermal processes occurring in boilers. The collected data is presented in a uniform description of the current state of the sold fuels. In the last point, the researchers were looking at the technical aspects of the fuels offered in relation to the existing emission standard for low-power boilers.

A Numerical Investigation into the Effectiveness of Multi-Element Pressure Screen Rotor Foils

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Sean Delfel ◽  
Carl Ollivier-Gooch ◽  
James Olson
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Investigation ◽  
Negative Pressure ◽  
Pressure Pulse ◽  
Angle Of Attack ◽  
Positive Pressure ◽  
Single Element ◽  
Past Work

Pressure screening is an efficient way to remove unwanted debris from a pulp stream, which improves the quality of the end product paper. Past work has found that increased foil camber and angle-of-attack improve the performance of pressure screen foil rotors by increasing the magnitude and width of the negative pressure pulse on the screen cylinder while at the same time reducing the magnitude of the positive pressure pulse on the screen cylinder. Too large an angle-of-attack or too much camber leads to separation of the flow over the foil and a loss in rotor performance, however. This study therefore investigates, using computational fluid dynamics, the ability of multi-element rotor foils to delay stall over the foil and improve upon the performance of an existing pressure screen rotor foil. In this study, the effect of foil angle-of-attack, flap angle, the geometry of the trailing edge of the main foil, and the positioning of the flap relative to the main foil were studied. A multi-element foil was developed based on the NACA 8312, a foil used in industrial pressure screen rotors. In general, stall was delayed and a larger angle-of-attack was obtained than the single-element foil, and increased camber was added to the foil by deflecting the flap. Positive pressure pulse on the screen cylinder approached a negligible value with both increasing angle-of-attack and increasing flap angle, while the negative pressure pulse increased in magnitude with both increasing angle-of-attack and flap angle before the foil began to separate and the suction was lost. The x-positioning of the flap was shown to have less of an effect on the foil performance than the y-positioning. All told, the magnitude of the negative pressure pulse was increased by 15% while at the same time eliminating the positive pressure pulse.

scholarly journals The Hepaticojejunostomy Technique with Intra-Anastomotic Stent in Biliary Diseases and Its Evolution throughout the Years: A Technical Analysis

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Demetrios Moris ◽  
Alexandros Papalampros ◽  
Michail Vailas ◽  
Athanasios Petrou ◽  
Michael Kontos ◽  
...  
Keyword(s):  
Biliary Obstruction ◽  
Technical Analysis ◽  
Definitive Treatment ◽  
Technological Evolution ◽  
Tips And Tricks ◽  
Robotic Approach ◽  
Bile Duct Injuries ◽  
Biliary Diversion ◽  
Anastomotic Strictures

Roux-en-Y hepaticojejunostomy (RYHJ) is currently considered as the definitive treatment for iatrogenic bile duct injuries and the principal representative of biliary diversion procedures. This technique has met many milestones of extensive evolution, particularly the last years of concomitant technological evolution (laparoscopic/robotic approach). Anastomotic strictures and leaks, which may have deleterious effects on the survival and quality of life of a patient with biliary obstruction of any cause, made the need of the development of a safe and efficient RYHJ compulsory. The aim of this technical analysis and the juxtaposed discussions is to elucidate with the most important milestones and technical tips and tricks all aspects of a feasible and reliable RYHJ technique that is performed in our center for the last 25 years in around 400 patients.

scholarly journals Study of breast implants mammography examinations for identification of suitable image quality criteria

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Cláudia Sá dos Reis ◽  
Isabelle Gremion ◽  
Nicole Richli Meystre
Keyword(s):  
Breast Cancer ◽  
Image Quality ◽  
Literature Review ◽  
Beam Energy ◽  
Quality Criteria ◽  
Breast Implants ◽  
Descriptive Statistics ◽  
Compression Force ◽  
Two Phases

Abstract Purpose To characterise the mammography technique used in breast cancer screening programmes for breast implants (BI) and to identify if the image quality (IQ) criteria available in literature are applicable to BI imaging. Methods The study was conducted in two phases: literature review to find IQ criteria used in mammography combining keywords in several sources; and assessment of 1207 BI mammograms using the criteria that was identified previously to see if they were achieved or not. An observation grid was used to collect information about positioning, beam energy, compression force, and exposure mode. Descriptive statistics and Student’s t test and χ2 test were performed according to the nature of the variables. Results Forty-seven out of 2188 documents were included in the analysis, with 13 items identified to assess the quality of positioning, 4 for sharpness, 3 for artefacts, and 2 for exposure parameters. After applying the criteria to BI mammograms, retroglandular fat was not included in 37.3% of the images. The “Pectoral-Nipple-Line” criterion was achieved in 35% of MLO/ML images. The placement of the implant (subpectoral/subglandular) or performing the Eklund had significant influence on the visible anatomy (p = < 0.005), alongside whether the breast was aligned to the detector’s centre. Conclusions Some of the criteria used to assess standard mammograms were not applicable to BI due to implant overlap. The alignment of the image with the detector’s centre seems to have an impact on the amount of visible tissue. Further studies are necessary to define the appropriate protocol, technique, and suitable quality criteria to assess BI mammograms.

Sign in / Sign up

Export Citation Format

Share Document