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http://repository.elizadeuniversity.edu.ng/jspui/handle/20.500.12398/13
2023-09-01T15:42:21ZTemperature changes with die profiles in axisymmetric forward extrusion process
http://repository.elizadeuniversity.edu.ng/jspui/handle/20.500.12398/1338
Title: Temperature changes with die profiles in axisymmetric forward extrusion process
Authors: Ajiboye, J.S.; Adeyemi, M.B.
Abstract: Transient heat transfer and temperature change due to varying die opening shapes in a direct extrusion of lead have been numerically investigated and presented. Upper bound method of analysis was used to evaluate the internal heat generation due to plastic deformation and frictional heat at various stages of the extrusion process. At the extrusion die land region, temperature rises with increasing complexity of die openings geometry with I-shaped section, giving the highest temperature rise, followed by T-shaped section, rectangular, circular shaped die openings with square section die opening, giving the least temperature rise for any given extrusion parameter. The die land zone shows increasing temperature rise with increasing friction coefficient, while increasing friction coefficient has no overall effect on the dead metal zone temperature rise. Increasing die land length leads to increasing contact area between the extrudate and the die resulting in increasing frictional power. It is, therefore, seen that die land is one of the critical factors to consider avoiding surface cracking or hot-shortness in extrusion.
Description: Staff publication2008-01-01T00:00:00ZTribological efficacy and stability of phospholipid-based membrane lubricants in varying pH chemical conditions
http://repository.elizadeuniversity.edu.ng/jspui/handle/20.500.12398/1020
Title: Tribological efficacy and stability of phospholipid-based membrane lubricants in varying pH chemical conditions
Authors: Pawlaka, Zenon; Urbaniak, Wieslaw; Afara, Isaac O.; Yusuf, Kehinde Q.; Banaszak-Piechowska, Agnieszka; Oloyede, Adekunle
Abstract: In this study, the authors examine the influence of joint chemical environment by measuring
changes in the tribological properties (friction coefficient and charge density) of contacting
surfaces of normal and degenerated cartilage samples in bath solutions of varying pH (2.0–9.0).
Bovine articular cartilage samples (n¼54) were subjected to several surface measurements,
including interfacial energy, contact angle, and friction coefficient, at varying pH. The samples
were delipidized and then subjected to the same measurement protocols. Our results reveal that the
interfacial energy and charge density, which have been shown to be related to friction coefficient,
decrease with pH in the acidic range and approach constant values at physiological (or synovial
fluid) pH of 7.4 and beyond it, i.e., toward basic pH domain. The authors conclude that this rather
complex response explains the long-term efficacy with respect to ageing and associated pH
changes, of the phospholipid layers that facilitate the almost frictionless, hydration–lubrication
involving contact in the mammalian musculoskeletal system.
Description: Staff Publication2016-01-04T00:00:00ZHISTOGRAM NORMALIZATION TECHNIQUE FOR PREPROCESSING MAMMOGRAPHIC IMAGES
http://repository.elizadeuniversity.edu.ng/jspui/handle/20.500.12398/476
Title: HISTOGRAM NORMALIZATION TECHNIQUE FOR PREPROCESSING MAMMOGRAPHIC IMAGES
Authors: Adepoju, Temilola M.; Adeyemo, Temitope T.; Fagbola, Temitayo M.; Omidiora, Elijah O.; Olabiyisi, Stephen O.
Abstract: images requires high computational capabilities. Pre-processing is one of the most important step in the mammogram analysis
due to poor captured mammographic image qualities. Pre-processing is basically used to correct and adjust the mammogram
image for further study and classification. Many image pre-processing techniques have been developed over the past decades
to help radiologists in diagnosing breast cancer. Most studies conducted have proven that a pre-processed image is easier for
radiologist to accurately detect breast cancer especially for dense breast. Different types of techniques are available for preprocessing
of mammograms, which are used to improve image quality, remove noise, adjust contrast, enhance the image and
preserve the edges within the image. This paper acquired 20 digital mammograms from Mammographic Image Analysis
Society (MIAS) database and uses Histogram Normalization algorithm for pre-processing of the mammograms. A percentage
of 95% was obtained. It was observed that the pre-processed mammographic images displayed breast abnormalities clearer
with little or no noise.2016-01-01T00:00:00Z