Factors Affecting Curling in Rolled Sheet

1973 ◽  
Vol 95 (2) ◽  
pp. 103-106 ◽  
Author(s):  
C. R. Heiple
Keyword(s):  
Leading Edge ◽  
Reduction Ratio ◽  
The Other ◽  
Rolled Sheet ◽  
Roll Speed ◽  
Factors Affecting ◽  
Height Reduction ◽  
Bottom Roll ◽  
Increasing Temperature ◽  
Roll Gap

The influence of several rolling parameters on curling during the rolling of sheet was investigated. The material studied was primarily 0.5 in. thick 2024 aluminum. The factors studied were different top and bottom roll diameters, differential strength through the thickness of the sheet, lubrication, roll-table height, reduction ratio, temperature, roll speed, and a beveled leading edge. The sheet curled toward the smaller roll, away from the better lubricated side, toward the strong side if one side was stronger than the other, and up when the entrance roll table was too high. Curling increased for greater reductions (under the conditions studied) and also increased slightly with increasing temperature. Curling was not sensitive to roll speed or a beveled leading edge. The curling observed can generally be explained on the basis of a shear in the roll gap because of different locations of the neutral points along the arcs of contact for the two rolls. Curling observed when one side of the sheet is significantly softer than the other appears to be due to greater elongation of the soft side during rolling.

scholarly journals Experimental study on the factors affecting torque of beam-type implant torque wrenches

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hiroki Shiba ◽  
Yuji Sato ◽  
Junichi Furuya ◽  
Tokiko Osawa ◽  
Akio Isobe ◽  
...  
Keyword(s):  
Coefficient Of Variation ◽  
Leading Edge ◽  
Beam Width ◽  
Factors Affecting ◽  
Tightening Force ◽  
Torque Wrench ◽  
Screw Breakage ◽  
Beam Type ◽  
Accuracy And Repeatability ◽  
Excellent Accuracy

Abstract Background Screw breakage and loosening are the most common mechanical complications associated with implant treatment, and they may occur due to excess or inadequate screw tightening torque. When fastening and fixing the implant superstructure, screws are tightened using a torque wrench, which is essential for an accurate tightening force. However, the characteristics of the torque wrench have not been fully verified. Therefore, we aimed to clarify the factors affecting the torque with a focus on beam-type torque wrenches, which are the main types of wrenches. Methods The torque values generated by beam-type torque wrenches from eight manufacturers were measured using a torque gauge. To investigate the influence of the location of the beam relative to the scale, measurements were performed with a scale aligned with the trailing edge, center, and leading edge of the beam respectively. Additionally, measurements were taken at 90°, 60°, and 30° to examine the effect of the angle at which the examiner read the torque value. Under each condition, a single examiner applied the recommended torque to each manufacturer's screws five times in a clockwise direction. The average measured torque, standard deviation, bias, and coefficient of variation were calculated and compared accordingly. Results Wrenches from six manufacturers demonstrated excellent accuracy for measurements at the center of the beam (bias within ± 4%). For measurements at 90°, equipments from five manufacturers displayed excellent accuracy (bias within ± 7%), and seven showed excellent repeatability (coefficient of variation ≤ 2%). Conclusion The scale should be aligned with the center of the beam and read from 90° while using a torque wrench. The accuracy and repeatability torques generated by the wrenches differed according to the manufacturer, scale width, scale line width, beam width, and distance between the scale and beam center. Based on these results, we suggest that a torque wrench must be selected after determining the difference in the structure of the torque wrench.

Milling Curves Influence in Ring Rolling Processes

2014 ◽  
Vol 622-623 ◽  
pp. 956-963 ◽  
Author(s):  
Luca Giorleo ◽  
Elisabetta Ceretti ◽  
Claudio Giardini
Keyword(s):  
Numerical Approach ◽  
The Other ◽  
Ring Rolling ◽  
Roll Speed ◽  
Forming Process ◽  
Industrial Case Study ◽  
Industrial Environment ◽  
Ring Shape ◽  
Deformation Processes

Ring Rolling is a complex hot forming process used for the production of shaped rings, seamless and axis symmetrical workpieces. The main advantage of workpieces produced by ring rolling, compared to other technological processes, is given by the size and orientation of grains, especially on the worked surface which give to the final product excellent mechanical properties. In this process different rolls (Idle, Axial, Guide and Driver) are involved in generating the desired ring shape. Since each roll is characterized by a speed law that can be set independently by the speed law imposed to the other rolls, an optimization is more critical compared with other deformation processes. Usually, in industrial environment, a milling curve is introduced in order to correlate the Idle and Axial roll displacement, however it must be underlined that different milling curves lead to different loads and energy for ring realization. In this work an industrial case study was modeled by a numerical approach: different milling curves characterized by different Idle and Axial roll speed laws (linearly decreasing, constant, linearly increasing) were designed and simulated. The results were compared in order to identify the best milling curve that guarantees a good quality ring (higher diameter, lower fishtail) with lower loads and energy required for manufacturing.

Investigation on Polymer Adsorption and Retention in a Polymer Flooded Reservoir

2013 ◽  
Vol 734-737 ◽  
pp. 1200-1203
Author(s):  
Shu Qiang Liu ◽  
Ji Cheng Zhang ◽  
Jin Cheng Xu
Keyword(s):  
Polymer Solution ◽  
Influencing Factors ◽  
Polymer Adsorption ◽  
Solution Concentration ◽  
Injection Rate ◽  
The Other ◽  
Injection Time ◽  
Factors Affecting ◽  
Dynamic Factors ◽  
Polymer Retention

During polymer flooding, certain amount of polymer would be lost. Polymer retention causes sweep volume expanding on one side, it also causes polymer loss on the other. Therefore, it is a very important topic to study the influencing factors of polymer retention. There are many factors affecting polymer retention process. This paper mainly studied the influence from dynamic factors such as polymer solution concentration, injection rate, injection time, injected pv number. This paper investigated the influence of these factors on polymer retention process, and optimized these factors to minimize polymer loss in reservoir.

Factors affecting changes in the intraocular pressure after phacoemulsification surgery

2020 ◽  
Vol 1 (3) ◽  
pp. 166-172
Author(s):  
Rita Dhamankar ◽  
◽  
Suhas S Haldipurkar ◽  
Tanvi Haldipurkar ◽  
Vijay Shetty ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Anterior Chamber ◽  
Axial Length ◽  
Anterior Chamber Depth ◽  
The Other ◽  
Factors Affecting ◽  
Factors Associated ◽  
Post Surgery ◽  
Unit Increase ◽  
The Mean

AIM: To assess the changes in anterior chamber parameters and examine the factors associated with changes in the intraocular pressure (IOP) in individuals who have undergone phacoemulsification surgery. METHODS: It is a longitudinal analysis of secondary clinical data collected from 105 non-glaucomatous eyes (82 patients) undergoing a cataract surgery. We studied the association between anterior chamber parameters, grade of cataract, demographics, and changes in the IOP over a period of three weeks. We also evaluated the association between the pressure-depth (PD) ratio and changes in the IOP during this time. RESULTS: The mean age (SD) of the 82 patients was 60.1±7.8y. The mean±standard deviation (SD) IOP was 15.06±3.36 mm Hg pre-operatively; it increased to 15.75±4.21 mm Hg on day one (P=0.20). In the multifactorial models, the mean IOP was -1.715 (95%CI: -2.795, -0.636) mm Hg on day 21±5 compared with the pre-operative values. The anterior chamber depth (ACD), axial length, age, sex, and grade of cataract were not significantly associated with changes in the IOP. Each unit increase in the PD ratio was associated with an increase in the mean IOP by 1.289 mm Hg (95%CI: 0.906, 1.671). After adjusting for pre-operative PD ratio, none of the other variables (ACD, axial length, temporal angle) were significantly associated with changes in mean IOP. CONCLUSION: The PD ratio was the single most important factor associated with the changes in post-operative IOP over three weeks post-surgery.

scholarly journals Dynamics and Protein–Solvent Interactions of Hemoglobin in T and R Quaternary Conformation

2002 ◽  
Vol 16 (3-4) ◽  
pp. 227-233 ◽  
Author(s):  
Chiara Caronna ◽  
Antonio Cupane
Keyword(s):  
Quaternary Structure ◽  
Dynamic Properties ◽  
Low Frequency ◽  
Helical Structure ◽  
Blue Shift ◽  
Peak Frequency ◽  
The Other ◽  
Solvent Interactions ◽  
Reported Data ◽  
Increasing Temperature

In this work we report the thermal behaviour of the amide I′ band of carbonmonoxy and deoxy hemoglobin in 65% v/v glycerolD8/D2O solutions and in the temperature interval 10–295 K. Following recent suggestions in the literature, we analyze the amide I′ band in terms of two components, one at about 1630 cm−1and the other at about 1650 cm−1, that are assigned to solvent‒exposed and buried α‒helical regions, respectively.For deoxy hemoglobin (in T quaternary structure) both components are narrower with respect to carbonmonoxy hemoglobin (in R quaternary structure), while the peak frequency blue shift observed, upon increasing temperature, for the component at about 1630 cm−1is smaller. The reported data provide evidence of the dependence of hemoglobin dynamic properties upon the protein quaternary structure and suggest a more compact α‒helical structure of hemoglobin in T conformation, with reduced population of low‒frequency modes involving the solvent and protein.

Ti STRIP PROPERTIES FABRICATED BY POWDER ROLLING METHOD

2010 ◽  
Vol 17 (02) ◽  
pp. 229-234 ◽  
Author(s):  
JAE-KEUN HONG ◽  
CHAE-HUN LEE ◽  
JEOUNG-HAN KIM ◽  
JONG-TAEK YEOM ◽  
NHO-KWANG PARK
Keyword(s):  
Rolling Speed ◽  
Strip Thickness ◽  
Roll Speed ◽  
Powder Morphology ◽  
Rolling Method ◽  
Edge Cracks ◽  
Roll Compaction ◽  
Ti Powder ◽  
Roll Gap ◽  
Size Powder

In the present study, the characteristics of the Ti powders fabricated by Hydride–Dehydride (HDH) were analyzed in terms of particle shape, size and size distribution. Ti powders were subjected to roll compaction and their microstructure and green densities were evaluated in terms of particle size, powder morphology, roll gap and rolling speed. Effects of blending elements having different powder sizes on densification properties were analyzed. The strip thickness was proportional to the roll gap up to 0.9 mm and the density of titanium strip was decreased with the increase in roll gap. As the roll speed increased, the strip density and thickness were decreased by using -200 mesh Ti powder. However, the effect of rolling speed for -400 mesh Ti powder was not greater than that of -200 mesh powder. The highest density by 93% was achieved by using -400 mesh Ti powder at 0.1 mm roll gap, however edge cracks and alligator cracks were occurred.

scholarly journals Determination of the delivered hemodialysis dose using standard methods and on-line clearance monitoring

2006 ◽  
Vol 63 (8) ◽  
pp. 743-747 ◽  
Author(s):  
Vlastimir Vlatkovic ◽  
Biljana Stojimirovic
Keyword(s):  
Cumulative Effect ◽  
Chronic Hemodialysis ◽  
Reduction Ratio ◽  
The Other ◽  
Treatment Quality ◽  
Monitoring Methods ◽  
Dialysis Dose ◽  
Co Morbidity ◽  
On Line ◽  
Urea Reduction Ratio

Background/aim: Delivered dialysis dose has a cumulative effect and significant influence upon the adequacy of dialysis, quality of life and development of co-morbidity at patients on dialysis. Thus, a great attention is given to the optimization of dialysis treatment. On-line Clearance Monitoring (OCM) allows a precise and continuous measurement of the delivered dialysis dose. Kt/V index (K = dialyzer clearance of urea; t = dialysis time; V = patient's total body water), measured in real time is used as a unit for expressing the dialysis dose. The aim of this research was to perform a comparative assessment of the delivered dialysis dose by the application of the standard measurement methods and a module for continuous clearance monitoring. Methods. The study encompassed 105 patients who had been on the chronic hemodialysis program for more than three months, three times a week. By random choice, one treatment per each controlled patient was taken. All the treatments understood bicarbonate dialysis. The delivered dialysis dose was determined by the calculation of mathematical models: Urea Reduction Ratio (URR) singlepool index Kt/V (spKt/V) and by the application of OCM. Results. Urea Reduction Ratio was the most sensitive parameter for the assessment and, at the same time, it was in the strongest correlation with the other two, spKt/V indexes and OCM. The values pointed out an adequate dialysis dose. The URR values were significantly higher in women than in men, p < 0.05. The other applied model for the delivered dialysis dose measurement was Kt/V index. The obtained values showed that the dialysis dose was adequate, and that, according to this parameter, the women had significantly better dialysis, then the men p < 0.05. According to the OCM, the average value was slightly lower than the adequate one. The women had a satisfactory dialysis according to this index as well, while the delivered dialysis dose was insufficient in men. The difference between the women and the men was significant. Conclusion. The application of OCM has shown that it is the most rigorous parameter for the assessment of adequacy and that its regular use would contribute to increasing of the delivered dialysis dose and improvement of the treatment quality.

scholarly journals Hydrothermal treatment of sprout-damaged grain: I. Effects on the technological quality of wheat

1978 ◽  
Vol 50 (3) ◽  
pp. 240-253
Author(s):  
Christina Westermarck-Rosendahl ◽  
Hannu Salovaara
Keyword(s):  
Amylase Activity ◽  
The Other ◽  
Processing Conditions ◽  
Falling Number ◽  
Gluten Quality ◽  
Heat Treated ◽  
Technological Quality ◽  
The One ◽  
Increasing Temperature

Two sprout-damaged wheat lots with the falling number values of 91 and 65 were heat-treated by immersing the grain in water of temperatures of 80, 85, 90 and 100°C, followed by rapid chilling in water. The purpose of the treatment was to suppress the excess a-amylase activity in the outer layers of the kernels. The a-amylase activity following the treatment was measured by the falling number test. The increase in the falling number value was the greater the longer the treatment lasted and the higher the water temperature was. Processing lasting 30 sec at 80, 85, 90 and 100°C increased the falling number value of the one lot from 91 to 105, 117, 133 and 238 and of the other lot from 65 to 69, 70, 98, 163, respectively. As the falling numbers increased the wet gluten content of the samples decreased. These changes had a negative correlation. The gluten quality showed heat damage when the amount of gluten had dropped by about 5 and 2 precentage units in the lots with the falling numbers 91 and 65, respectively. This occurred at processing of the lot of better quality for 70, 20, 13 and 6 sec in the order of increasing temperature. The corresponding durations for the other lot were above 60, 30, 20 and 6 sec. During these treatments the falling number values rose from 91 to 104—129 and from 65 to 70—71. These results were confirmed by farinogram and extensigram determinations and by baking tests. The same processing conditions affected more severely the lot having the better initial quality than the lot with greater sprout damages.

scholarly journals Using Hotspots Algebra to analyze crime events and their urban context

2017 ◽  
Vol 18 (1) ◽  
pp. 9-26
Author(s):  
Lenin Heredia G. ◽  
Germán E. Bravo C.
Keyword(s):  
Temporal Analysis ◽  
The Other ◽  
Crime Analysis ◽  
Temporal Context ◽  
Urban Context ◽  
Factors Affecting ◽  
Spatial Factors ◽  
Spatial Influence ◽  
Police Agencies ◽  
The Subject

Hotspots analysis is essential in the criminology field and quite important in decisions making for police agencies because it permits the enhancement of allocation of police resources for timely and adequate actions. There exist different techniques for analysis and generation of hotspots, limited by its difficulty to consider other urban and demographic factors that could be the cause of the emergence of these hotspots or their influence over other factors. On the other hand, it is also difficult and unusual to analyze hotspots in a temporal context. This paper seeks, through spatial-temporal operations based in hotspots, to go beyond of classical crime analysis with hotspots, by looking for the spatial influence of other spatial factors over and analyzing also their relationship in a temporal context. The paper initially presents and analyze the performance of various techniques for hotspot generation and determines that STAC technique from CrimeStat is the more suitable for the proposed objective. Then, it defines a hotspot algebra allowing the combined study of crime and spatial factors affecting it and/or been affected by crime events. Temporal analysis includes the hotspots generation for days of the week and/or months in a year. In this way it is possible to study causality relationships and/or correlations among the studied phenomena and the spatial-temporal environment where crime occurs. Therefore, it is possible to define and apply informed actions, primarily concerning the allocation of police resources. Finally, it shows some application examples, thematic as well as temporal analysis, of hotspot algebra using crime data from Bogota for the years 2011 to 2013; finally, some future works in the subject are proposed.

scholarly journals Factors Affecting Language Proficiency in Heritage Language: The Case of Young Russian Heritage Speakers in Spain

2021 ◽  
Vol 14 (2) ◽  
pp. 303-329
Author(s):  
Tamara Vorobyeva ◽  
Aurora Bel
Keyword(s):  
Language Proficiency ◽  
Significant Relationship ◽  
Heritage Language ◽  
Language Use ◽  
Age Of Onset ◽  
The Other ◽  
Significant Variable ◽  
Heritage Speakers ◽  
Factors Affecting ◽  
Family Language

Abstract This study focuses on the issue of language proficiency attainment among young heritage speakers of Russian living in Spain and examines factors that have been claimed to promote heritage language proficiency, namely, age, gender, age of onset to L2, quantity of exposure and family language use. A group of 30 Russian-Spanish-Catalan trilingual children aged 7–11 participated in the study. In order to measure heritage language proficiency (L1 Russian), oral narratives were elicited. The results demonstrated a significant relationship between L1 proficiency and three sociolinguistic variables (age of onset to L2, quantity of exposure and family language use). Additionally, the multiply regression model demonstrated that the only significant variable affecting language proficiency was family language use and it accounted only for 33% of the variation of children’s language proficiency. The study raises the question about what are the other, yet unknown factors, which can affect heritage language proficiency.

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