Extrusion of Soft- and Medium-Grade Alloys

2000 ◽  
pp. 149-186
Keyword(s):  
Aluminum Alloys ◽  
Best Practices ◽  
Cross Sections ◽  
Extrusion Pressure ◽  
Important Process ◽  
Process Variables ◽  
Ram Speed

Abstract This chapter discusses the extrusion characteristics of relatively soft aluminum alloys. It begins by identifying alloy designations within the class and the types of extrusions made from them. It then explains how extruded shapes and cross-sections are defined and how to analyze and assess important process variables such as runout, extrusion pressure, ram speed, and butt thickness. It also provides best practices for various operations and explains how to identify and remedy common extrusion defects.

The Effect of Process Variables on Extrusion Pressures of Lead

1959 ◽  
Vol 81 (3) ◽  
pp. 207-214 ◽  
Author(s):  
J. Frisch ◽  
E. G. Thomsen
Keyword(s):  
Room Temperature ◽  
Extrusion Ratio ◽  
Extrusion Pressure ◽  
White Lead ◽  
Cylinder Wall ◽  
Process Variables ◽  
Pure Lead ◽  
Commercially Pure ◽  
Wide Range

Billets of commercially pure lead, 2 in. diam × 3 in. long were extruded at room temperature through five different die contours at ram speeds up to 50 ipm. It was found that, for the direct and indirect extrusions, with good lubrication (white lead in oil) and with good cylinder-wall finish, the extrusion pressure-displacement diagrams were essentially the same. The concentric and eccentric single-bar and multibar extrusions at constant extrusion ratio required approximately the same pressures when extruded at identical speeds. The extrusion pressures over the wide range of speeds investigated showed approximate linearity when plotted on log-log co-ordinates.

scholarly journals Obesity Prevention in Early Child Care Settings

2016 ◽  
Vol 44 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Marilyn S. Nanney ◽  
Tara L. LaRowe ◽  
Cynthia Davey ◽  
Natasha Frost ◽  
Chrisa Arcan ◽  
...  
Keyword(s):  
Best Practices ◽  
Cross Sections ◽  
Best Practice ◽  
Evaluation Studies ◽  
Participation Rate ◽  
Sampling Procedure ◽  
Adult Health ◽  
Home Based ◽  
Early Child Care ◽  
Family Home

Background. Long-term evaluation studies reveal that high-quality early care and education (ECE) programs that include a lifestyle component predict later adult health outcomes. The purpose of this article is to characterize the nutrition and physical activity (PA) practices, including implementation difficulty and barriers, of licensed center- and family home-based ECE programs serving 2- to 5-year-old children in Minnesota (MN) and Wisconsin (WI). Method. A stratified random sampling procedure was used to select representative cross sections of licensed ECE providers in MN and WI. A total of 2,000 providers (1,000 center-based, 1,000 family home-based) were randomly selected and invited to respond to a 97-item survey with questions representing (1) nutrition and PA practices, (2) barriers to meeting nutrition and PA best practices, and (3) written and implemented nutrition and PA policies. Summated scales were constructed for nutrition-related (range 0-15; Cronbach’s α = .86) and for PA-related best practices (range 0-10; Cronbach’s α = .82). Results. A total of 823 providers returned surveys between August 2010 and March 2011, resulting in a 44% bistate participation rate. Across all programs an average ( SD) of 7.0 (4.1) nutrition best practices were already implemented. Center-based providers reported on average 0.8 additional nutrition best practice (7.4 vs. 6.6, p = .01). Across all programs an average ( SD) of 5.2 (3.1) PA best practices were already implemented. Center-based providers reported on average one more PA best practice (5.3 vs. 4.3, p < .01). The cost of healthy food and the weather were identified as barriers by 80% of providers, regardless of program type.

Microchannel Arrays in Borophosphosilicate Glass for Photonic Device and Optical Sensor Applications

2005 ◽  
Vol 872 ◽  
Author(s):  
Claire L. Callender ◽  
Patrick Dumais ◽  
Chantal Blanchetière ◽  
Christopher J. Ledderhof ◽  
Julian P. Noad
Keyword(s):  
Cross Sections ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Photonic Devices ◽  
Two Dimensional ◽  
High Temperature Annealing ◽  
Process Variables ◽  
Sensor Applications ◽  
Silica Layers ◽  
Borophosphosilicate Glass

AbstractThe fabrication of two-dimensional uniform arrays of microchannels in borophosphosilicate glass (BPSG) layers deposited by plasma-enhanced chemical vapor deposition (PECVD) is presented. The microchannels, with circular cross-sections of 2-3 μm diameter, are formed by depositing specific thicknesses of BPSG over periodic ridge/space templates etched into underlying silica layers using reactive ion etching (RIE). High temperature annealing results in reflow of the BPSG and the formation of uniform circular or cylindrical voids between the template ridges. Control of microchannel size and geometry through process variables is reported, and exploitation of the microfluidic and optical properties of microchannels and integrated waveguides for applications in optical sensing and photonic devices is demonstrated

scholarly journals Modeling of REE and Fe Extraction from a Concentrate from Araxá (Brazil)

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 451 ◽  
Author(s):  
Marisa Nascimento ◽  
Flávio Lemos ◽  
Rogério Guimarães ◽  
Clóvis Sousa ◽  
Paulo Soares
Keyword(s):  
Laboratory Experiments ◽  
Earth Element ◽  
Process Variable ◽  
Optimization Method ◽  
Chemical Processing ◽  
Important Process ◽  
Mass Ratio ◽  
Process Variables ◽  
Acid Processing ◽  
Roasting Temperature

The study aimed to employ a comprehensive methodology for the acid processing of a rare earth element (REE) concentrate obtained from the ore from Araxá (MG-Brazil). The most important process variables have been identified and their levels determined to maximize REE extraction (%RE) and minimize Fe extraction (%Fe). The thermodynamic analysis showed that the roasting temperature (TF) is crucial for the control of Fe solubilization in the aqueous leaching step of the acid processing. A statistic design of laboratory experiments and a process optimization method were applied to address the interaction among the process variables. Experimental results showed that a TF of about 700 °C can significantly reduce the Fe concentration in the aqueous leaching liquor. Mathematical models were proposed to predict the effect of process variable on REE and Fe extraction of the concentrate. A multi-objective technique was employed for optimization of chemical processing and the best conditions were reached for roasting temperature (TF) = 700 °C, acid to sample mass ratio (ACs) = 0.8 and leaching time (tL) = 20 min, which led to %RE = 96.91% and %Fe = 21.69%.

How do avatar attractiveness and customization impact online gamers’ flow and loyalty?

2019 ◽  
Vol 29 (2) ◽  
pp. 349-366 ◽  
Author(s):  
Gen-Yih Liao ◽  
T.C.E. Cheng ◽  
Ching-I Teng
Keyword(s):  
Structural Equation Modeling ◽  
Social Identity ◽  
Structural Equation ◽  
Design Methodology ◽  
Total Concentration ◽  
Equation Modeling ◽  
Important Process ◽  
Process Variables ◽  
Content Type ◽  
Flow Theories

Purpose Avatars are known to be influential in gaming communication. However, little is known about how avatar attractiveness and customization impact online gamers’ flow, i.e., the experience of total concentration with intrinsic enjoyment and loyalty. Grounded in social identity and flow theories, the purpose of this paper is to construct a model to explain how avatar attractiveness and customization can impact online gamers’ flow and loyalty. Design/methodology/approach The responses of 1,944 online gamers are collected. Structural equation modeling is used for analyses. Findings The analytical results indicate that avatar attractiveness and customization are positively related to avatar identification, which is positively related to flow, and then to online gamer loyalty. In addition, avatar identification and flow are important process variables in the above relations. Originality/value This study is novel in being the first attempt to apply social identity and flow theories to explain how avatar attractiveness and customization contribute to online gamers’ flow and loyalty.

Enantioselective extraction of hydrophilic 2-chloromandelic acid enantiomers by hydroxypropyl-β-cyclodextrin: experiments and modeling

2013 ◽  
Vol 67 (2) ◽  
Author(s):  
Cong-Shan Zhou ◽  
Ping Xu ◽  
Ke-Wen Tang ◽  
Xin-Yu Jiang ◽  
Tao Yang ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Extraction Efficiency ◽  
Reactive Extraction ◽  
Phase Reaction ◽  
Important Process ◽  
Process Variables ◽  
Model Data ◽  
Cyclodextrin Derivatives ◽  
Enantioselective Extraction ◽  
Extraction Model

AbstractEnantioselective extraction of hydrophilic 2-chloromandelic acid (CMA) enantiomers from organic to aqueous phase with hydroxypropyl-β-cyclodextrin (HP-β-CD) as the selector was investigated. Equilibrium of the extraction system was modeled using a reactive extraction model with a homogeneous aqueous phase reaction. The influence of important process variables on the extraction efficiency, such as the type of the organic solvent and β-cyclodextrin derivatives (β-CDs), concentration of the selector, pH and temperature, was investigated by experiment and modeling. Important parameters of this model were determined experimentally. Results showed that the experimental data agree with the model prediction perfectly and the model was further applied to accurately predict the extraction efficiency influenced simultaneously by pH and the concentration of HP-β-CD. Combining the experiment and the model data, the best extraction conditions were: pH of 2.5, HP-β-CD concentration of 0.05 mol L−1, and temperature of 5°C, providing the enantioselectivity of 1.285 and the performance factor (pf) of 0.011.

Important process variables in chromate ion exchange

1986 ◽  
Vol 20 (2) ◽  
pp. 149-155 ◽  
Author(s):  
Arup K. Sengupta ◽  
Dennis. Clifford
Keyword(s):  
Ion Exchange ◽  
Important Process ◽  
Process Variables ◽  
Chromate Ion

Solid Welding Conditions for Seam and Hollow Extrusion Process of 7075 Aluminum Alloy

2011 ◽  
Vol 479 ◽  
pp. 62-73 ◽  
Author(s):  
Quang Cherng Hsu ◽  
Kun Hong Kuo ◽  
Chi Peng Hsu
Keyword(s):  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Cross Sections ◽  
High Strength ◽  
Extrusion Process ◽  
Protective Atmosphere ◽  
Porthole Die ◽  
Die Structure ◽  
Welding Strength ◽  
Good Agreement

Direct extrusion by porthole – bridge die configuration has been successfully used to fabricate products with hollow cross sections for 6000 series aluminum alloys. However, if for 7000 series aluminum alloys, this situation alerts since different alloy composition such as Cu causing hollow extrusion failed due to not enough welding strength in seam. In order to determine the solid welding conditions during hollow extrusion with porthole die structure for high strength aluminum alloy, an easy tooling configuration has been designed. The proposed method is easy and cheap because there is no necessary to conduct experiment in controlled environment such as in vacuum chamber of Gleeble test or in a protective atmosphere. A seam and hollow extrusion for square tube has been conducted to obtain the welding strength comparison to the proposed solid welding method which shows good agreement.

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