Investigation of deformation induced micro to macro scale surface roughness

In the present work the relationship between deformation and deformation induced surface roughness of 100 micron thick annealed AISI 304 stainless steel was investigated at the meso scale. This work is a continuation of the previous work by the authors where roughness values were determined at the apex of the bulge test samples at micro scale. The apex is believed to be the region of highest stress and strain in a typical bulge process in a circular die. The material was deformed using a biaxial bulge test through hydraulic fluid pressure. The strains on the workpieces were measured with respect to the forming pressure. The surface roughness was measured by scanning the interior (concave) area of bulge with Bruker GTK-17 optical profilometer over an area of 1.3mm x 1mm. The results show linear relationship between roughness and deformation strain, and it establish a similar trend with roughness measured at micro scale

Accelerating Student Success: The Case for Corequisite Instruction

The successes of corequisite remediation courses and supplemental instruction over traditional remediation courses such as the modular Math Essentials have been widely and recently documented (Logue, Watanabe-Rose, & Douglas, 2016). Corequisite reform is an important strategy to improve student completion of higher education goals. A robust corequisite model integrates gateway course content with lifelong tools such as time management and study skills that help students beyond the scope of one course. Corequisite remediation may not completely eliminate developmental courses; however, “a fundamental redesign of the support system for academically underprepared students” will include corequisite remediation (Vandal, 2014). This broader “support system” may integrate corequisite courses with the current (or similar) modular curriculum with non-modular precollege courses such as MTH 5 or MTH 9 in the Virginia Community College System (VCCS). Student placement into the optimal teaching/learning mode may be as key as course level placement (Bickerstaff, 2016). Corequisite remediation provides the VCCS with a powerful tool for student success. Wise integration of corequisite courses as part of a robust remediation program makes the vision of the VCCS strategic plan, Complete 2021, more clearly attainable

BASEBALL PITCHING BIOMECHANICS AFTER SURGERY

Baseball pitchers with and without histories of elbow or shoulder surgery were tested with a 240 Hz automated 3D motion capture system. No differences were found between pitchers with history of UCL reconstruction and matched controls. Pitchers tested shortly after returning from UCL repair demonstrated reduced elbow extension, elbow velocity, and shoulder velocity compared to a control group, but it is unknown whether these few kinematic differences resolve with time. Pitchers with a history of SLAP repair produced less shoulder horizontal abduction, shoulder external rotation, and forward trunk tilt than matched controls. The Thoracic Outlet Syndrome case report demonstrated significantly more shoulder abduction after surgery. Thus the ability to return to normal pitching biomechanics after injury depends upon the type of surgery

MetaQC: objective quality control and inclusion/exclusion criteria for genomic meta-analysis

Genomic meta-analysis to combine relevant and homogeneous studies has been widely applied, but the quality control (QC) and objective inclusion/exclusion criteria have been largely overlooked. Currently, the inclusion/exclusion criteria mostly depend on ad-hoc expert opinion or naïve threshold by sample size or platform. There are pressing needs to develop a systematic QC methodology as the decision of study inclusion greatly impacts the final meta-analysis outcome. In this article, we propose six quantitative quality control measures, covering internal homogeneity of coexpression structure among studies, external consistency of coexpression pattern with pathway database, and accuracy and consistency of differentially expressed gene detection or enriched pathway identification. Each quality control index is defined as the minus log transformed P values from formal hypothesis testing. Principal component analysis biplots and a standardized mean rank are applied to assist visualization and decision. We applied the proposed method to 4 large-scale examples, combining 7 brain cancer, 9 prostate cancer, 8 idiopathic pulmonary fibrosis and 17 major depressive disorder studies, respectively. The identified problematic studies were further scrutinized for potential technical or biological causes of their lower quality to determine their exclusion from meta-analysis. The application and simulation results concluded a systematic quality assessment framework for genomic meta-analysis

The Development of a microscale tube hydroforming test bed and novel sealing system: A work in progress

A microscale/multiscale tube hydroforming system including tooling and controls is being designed and implemented at the University of Louisiana at Lafayette as part of a collaborative effort with Michigan Technological University. The sealing system demonstrates the evolution of the flared tube ends approach for tube end sealing to a spherical metal-on-metal sealing system. One of the features of the tooling is that while the tooling is capable of producing microscale hydroforming, the entire system can now be made using conventional CNC machining operations. Preliminary work has begun for implementing control of the hydroforming process using a PLC and a custom built continuous high pressure system capable of 415 MPa is described. Preliminary results for formed sample tubes are discussed

Analytical and experimental evaluation of flow characteristics of ANNEALED AISI 304 stainless steel sheet in multi-scale bulge forming

©2017 ASME. Micro and multiscale material properties are one area that must be considered in order to satisfy the need for increased utilization of miniature devices manufactured with microscale hydroforming processes. The objective of the present research is to evaluate the properties of 0.2-mm thick AISI 304 stainless steel using circular dies of 5 mm and 11 mm diameter and elliptical hydraulic bulge forming processes with minor diameters of 11 mm and various aspect ratios. Macroscale analytical methods for circular dies were compared to experimental results. For the elliptical dies, Banabic\u27s method and a new modification of Banabic\u27s method, utilizing work by Rees were used to obtain power law material properties. The Ekineev-Kruglov method was shown to be the best analytical method estimating material properties from circular dies. For elliptical dies, based upon finite element simulations, it was seen that Banabic\u27s method resulted in the best agreement with experimental results. However, it was found that neither method for elliptical dies resulted in reasonable dome height predictions compared to those from microscale tensile tests

The Developing Economist, Volume 6

Contents: Climate Shocks, Vulnerability and Migration: Evidence from Rural Malawi // by Cara Braasch, University of Illinois at Urbana-Champaign (p. 10) -- Does Greater Crop Yield Result in Better Nutritional Outcomes? // by Preeta Raghunathan, Macalester College (p. 34) -- Paid Family Leave in California and the Timing of Pregnancies // by Allyson Emblom, George Mason University (p. 64) -- Saving Failing Coal Mines: The Impact of Tax Policy on Coal Mining // by Tanner Bowen, University of Pennsylvania (p. 91)Economic

Strain control in an intelligent die based upon local force control and blank holder forces

An experimental evaluation of the strains in an oval stamp forming die is presented. The die design included a flexible blank holder and active draw beads. The die was instrumented with local punch force and wrinkle sensors and control systems were developed in order to follow local punch force and wrinkle trajectories. Strains were measured after pan forming for both open and closed-loop tests. The relation between blank holder force, draw bead penetration, and strains were explored in the critical strain region of the formed pan. Closed-loop control of the local punch forces at the die ends was established using blank holder forces. The strains for tests with various lubrication conditions and draw bead penetrations were compared. It was observed that there is a tendency for the strains in critical locations to converge or remain constant for the closed-loop control tests while the strains tended to increase with blank holder force for open-loop tests. It was concluded that by controlling local punch forces, strain is indirectly controlled. Copyright © 2009 by ASME