Preliminary Study of O&M Opportunities at the University of Texas Medical Branch at Galveston, Submitted to The Energy Management and Operations Department at UTMB Galveston

At the request of the Energy Management and Operations Department at the University of Texas Medical Branch at Galveston, the Energy Systems Laboratory at the Texas A&M University performed the preliminary study of O&M Opportunities at the 49 buildings (over 3.5 million ft2 floor area) and its central plant. The central plant provides the chilled water and steam to all of these buildings. Constant air volume systems are used in 48 buildings while single duct variable air volume systems are used in the Medical Research Building, which was built in 1993. Three major O&M opportunities were identified in the UTMB buildings and the central plant: (1) Optimizing the outside air reset schedules of the air handling units; (2) Controlling the steam pressure at 125 psi or lower; and (3) Optimizing the chilled water and cooling tower water set points

Accuracy and Surface Quality Improvements in the Manufacturing of Ti-6Al-4V Parts Using Hot Single Point Incremental Forming

The present work focuses on the manufacturing of Ti-6Al-4V parts using hot single point incremental forming (SPIF), a non-conventional forming technology mainly oriented toward the fabrication of prototypes, spare parts, or very low volume series. In the used procedure, the entire sheet is heated and kept at uniform temperature while the tool incrementally forms the part, with the limited accuracy of the obtained parts being the major drawback of the process. Thus, this work proposes two approaches to improve the geometric accuracy of Ti-6Al-4V SPIF parts: (i) correct the tool path by applying an intelligent process model (IPM) that counteracts deviations associated with the springback, and (ii) skip overforming deviations associated with the deflection of the sheet along the perimeter of the part based on a design improvement. For this purpose, a generic asymmetric design that incorporates features of a typical aerospace Ti-6Al-4V part is used. The results point out the potential of both solutions to significantly improve the accuracy of the parts. The application of the IPM model leads to an accuracy improvement up to 49%, whereas a 25.4% improvement can be attributed to the addendum introduction. The geometric accuracy study includes the two finishing operations needed to obtain the part, namely decontamination and trimming.Research leading to these results was done within the project INMA—Innovative manufacturing of complex titanium sheet components. This research was funded by the European Union´s Seventh Framework Programme for research, technological development, and demonstration under grant agreement number 266208

Henry Ford vs. assembly line balancing

Ford’s Assembly Line at Highland Park is one of the most influential conceptualizations of a production system. New data reveal Ford’s operations were adaptable to strongly increasing and highly variable demand. These analyses show Ford’s assembly line was used differently than modern ones and their production systems were more flexible than previously recognized. Assembly line balancing theory largely ignores earlier practice. It will be shown that Ford used multiple lines flexibly to cope with large monthly variations in sales. Although a line may be optimized to yield lowest cost production, systems composed of several parallel lines may yield low cost production along with output and product flexibility. Recent research on multiple parallel lines has focussed on cost effectiveness without appreciating the flexibility such systems may allow. Given the current strategic importance of flexibility it should be included in such analyses as an explicit objective

STV-based Video Feature Processing for Action Recognition

In comparison to still image-based processes, video features can provide rich and intuitive information about dynamic events occurred over a period of time, such as human actions, crowd behaviours, and other subject pattern changes. Although substantial progresses have been made in the last decade on image processing and seen its successful applications in face matching and object recognition, video-based event detection still remains one of the most difficult challenges in computer vision research due to its complex continuous or discrete input signals, arbitrary dynamic feature definitions, and the often ambiguous analytical methods. In this paper, a Spatio-Temporal Volume (STV) and region intersection (RI) based 3D shape-matching method has been proposed to facilitate the definition and recognition of human actions recorded in videos. The distinctive characteristics and the performance gain of the devised approach stemmed from a coefficient factor-boosted 3D region intersection and matching mechanism developed in this research. This paper also reported the investigation into techniques for efficient STV data filtering to reduce the amount of voxels (volumetric-pixels) that need to be processed in each operational cycle in the implemented system. The encouraging features and improvements on the operational performance registered in the experiments have been discussed at the end

Tensile force monitoring on large winch-assist forwarders operating in British Columbia

The forest industry around the world is facing common challenges in accessing wood fiber on steep terrain. Fully mechanized harvesting systems based on specialized machines, such as winch-assist forwarders, have been specifically developed for improving the harvesting perfor- mances in steep grounds. While the mechanization process is recognized as a safety benefit, the use of cables for supporting the machine traction needs a proper investigation. Only a few studies have analyzed the cable tensile forces of winch-assist forwarders during real operations, and none of them focused on large machines normally used in North America. Consequently, a preliminary study focused on tensile force analysis of large winch-assist forwarders was conducted in three sites in the interior of British Columbia during the fall of 2017. The results report that in 86% of the cycles, the maximum working load of the cable was less than one-third of the minimum breaking load. The tensile force analysis showed an expected pattern of minimum tensile forces while the forwarders were traveling or unloading on the road site and high tensile forces when operating on steep trails, loading or traveling. Further analysis found that the maximum cycle tensile forces occurred most frequently when the machines were moving uphill, independently of whether they were empty or loaded. While the forwarders were operating on the trails, slope, travel direction, and distance of the machines from the anchor resulted statistically significant and able to account for 49% of tensile force variability. However, in the same conditions, the operator settings accounted for 77% of the tensile force variability, suggesting the human factor as the main variable in cable tensile force behavior during winch-assist operations

Evaluation of the volumetric erosion of spherical electrical contacts using the defect removal method

Volumetric erosion is regarded as a significant index for studying the erosion process of electrical switching contacts. Three-dimensional (3-D) surface measurement techniques provide an approach to investigate the geometric characteristics and volumetric erosion of electrical contacts. This paper presents a concrete data-processing procedure for evaluating volumetric erosion of spherical electrical contacts from 3-D surface measurement data using the defect removal method (DRM). The DRM outlined by McBride is an algorithm for evaluating the underlying form (prior to erosion) parameters of the surfaces with localized erosion and allowing the erosion characteristics themselves to be isolated. In this paper, a number of spherical electrical contacts that had undergone various electrical operations were measured using a 3-D surface profiler, the underlying form parameters of the eroded contacts were evaluated using the DRM, and then the volumetric erosions were isolated and calculated. The analysis of the correlations between the volumetric erosion and the number of switching cycles of electrical operation that the contacts had undergone showed a more accurate and reliable volumetric erosion evaluation using the DRM than that without using the DRM

Surgical volume and center effects on early mortality after pediatric cardiac surgery: 25-year experience from the pediatric cardiac care consortium

University of Minnesota M.S. thesis. June 2012. Major: Clinical Research. Advisor: William Thomas. 1 computer file (PDF); vii, 33 pages.Context: Mortality after pediatric cardiac surgery varies substantially among centers, but the impact of center-specific effects remains poorly understood. Objective: To assess the impact of surgical volume and other center effects on early mortality after pediatric cardiac surgery. Design, Setting, Participants: Retrospective cohort study utilizing risk-adjusted outcome data from the Pediatric Cardiac Care Consortium, a consortium of small and medium size North American centers (<500 cases/year). Hierarchical multivariate logistic regression analysis was used to assess the impact of surgical volume and center effects over time. Main outcome measure: Risk-adjusted early post-operative mortality. Results: From 1982 to 2007, 49 centers reported 109,447 operations. Patient characteristics varied significantly among centers. The adjusted odds ratio (OR) for mortality decreased more than 10-fold over the study period (1982 vs. 2007 OR 12.27, 95% CI: 8.52-17.66, p<0.001). Surgical volume was inversely associated with odds of death (additional 100 cases/year OR 0.84, 95% CI: 0.78-0.90, p<0.001). The volume effect was fairly consistent across age groups, risk categories (except the lowest), and time periods. Risk category was the most significant predictor of mortality, while time period, patient age, and a volume-independent center effect had additional weak effects. Conclusions: Mortality after pediatric cardiac operations has decreased significantly over the last 25 years. RACHS-1 risk category remains the strongest predictor of post-operative mortality. Center-specific variation exists and is only partially explained by operative volume. Low-risk pediatric cardiac surgery is safely performed at centers performing fewer than 200 cases/year; regionalization or other quality-improvement strategies may be warranted for complex cases