Development of Various Fibre Reinforced Cementitious Composites

This dissertation presents the results obtained through a comprehensive experimental work that was carried out in two different phases. Phase I determined the mechanical and durability performance of cementitious composites reinforced Kraft pulp fibres. Two engineered fibers, along with a commercially available unmodified fiber, were used in reinforcing cementitious materials. These fibres are called mechanically modified fibre and chemically treated fibre, and these are not yet commercially available. This study was completed to determine the strength, durability, and interfacial properties of the reinforced cementitious composites. Test results showed an increase in the permeability characteristics for the reinforced concretes. Hence, these fibres reduced the compressive strength and durability of reinforced concretes as compare to the unreinforced concrete. However, the two engineered fibres performed better than the unmodified fibre in terms of compressive strength, chloride ion permeability and water sorptivity. Further, the drying shrinkage strain was reduced considerably when only 1% chemically treated fiber was added. In phase II, a study was completed to experimentally determine the influence of partial and full replacement of slag with fly ash on the mechanical and durability performance of engineered cementitious composites. Test results showed that mixtures containing slag exhibited strain-hardening like behaviour and a comparable ductility property as engineered cementitious composites containing fly ash. Further, slag blends were found to be significant in reducing permeability in terms of rapid chloride penetration, sorptivity, and water absorption at both 28 and 90 days. However, higher drying shrinkage strains were observed for mixtures containing slag when compared to fly ash mixtures

Potential risk factors for diabetic neuropathy: a case control study

BACKGROUND: Diabetes mellitus type II afflicts at least 2 million people in Iran. Neuropathy is one of the most common complications of diabetes and lowers the patient's quality of life. Since neuropathy often leads to ulceration and amputation, we have tried to elucidate the factors that can affect its progression. METHODS: In this case-control study, 110 diabetic patients were selected from the Shariati Hospital diabetes clinic. Michigan Neuropathic Diabetic Scoring (MNDS) was used to differentiate cases from controls. The diagnosis of neuropathy was confirmed by nerve conduction studies (nerve conduction velocity and electromyography). The multiple factors compared between the two groups included consumption of angiotensin converting enzyme inhibitors (ACEI), blood pressure, serum lipid level, sex, smoking, method of diabetes control and its quality. RESULTS: Statistically significant relationships were found between neuropathy and age, gender, quality of diabetes control and duration of disease (P values in the order: 0.04, 0.04, < 0.001 and 0.005). No correlation was found with any atherosclerosis risk factor (high BP, hyperlipidemia, cigarette smoking). CONCLUSION: In this study, hyperglycemia was the only modifiable risk factor for diabetic neuropathy. Glycemic control reduces the incidence of neuropathy, slows its progression and improves the diabetic patient's quality of life. More attention must be paid to elderly male diabetic patients with poor diabetes control with regard to regular foot examinations and more practical education

Frequency and Nature of Incidental Extra-Enteric Lesions Found on Magnetic Resonance Enterography (MR-E) in Patients with Inflammatory Bowel Diseases (IBD)

The aim of this study was to determine the occurrence of extra-enteric findings in a large cohort of patients undergoing magnetic resonance enterography (MR-E) and to classify the clinical significance of these findings.We retrospectively analyzed 1154 MR-E performed in 1006 patients referred to our radiological department between 1999-2005. The reasons for referral were suspected or proven inflammatory bowel diseases (IBD) (n = 710), further diagnostic work-up for small bowel disease because of non-specific abdominal symptoms (SBD; n = 182) or suspected small bowel malignancies (SBM; n = 114). All extra-enteric findings were reviewed by a radiologist and a gastroenterologist and were classified as having high, moderate, or low significance for further diagnostic or therapeutic procedures.The average age of all patients was 40+/-16 (Mean+/-SD) years (y) (IBD 35+/-13 y; SBD 49+/-16 y; SBM 57+/-15 y). A total of 1113 extra-enteric findings were detected in 600 of 1006 patients (59.6%). Of these findings 180 (16.2%) were judged as having a high, 212 (19.0%) a moderate and 721 (64.8%) a low significance. On a per group basis in patients with IBD 12.0% of the findings were of major clinical significance compared to 13.7% and 33.3% in patients with SBD and SBM, respectively. The most common major findings were abscesses (69.9%) in the IBD group and extraintestinal tumors, metastases or masses in the SBD and SBM groups (41.9% and 74.2%, respectively).MR-E reveals a substantial number of extra-enteric findings, supporting the role of a cross-sectional imaging method for the evaluation of the small bowel

Strength and permeability properties of self-compacting concrete with cold bonded fly ash lightweight aggregate

This paper presents the results of an experimental study on the hardened characteristics of the self-compacting concretes made with cold bond fly ash lightweight aggregates. Binary and ternary use of fly ash (FA) and silica fume (SF) blends have been considered in the production of self-compacting cold bonded fly ash lightweight aggregate concretes (SCLWCs). For this, a total of 9 SCLWC mixtures were proportioned having constant water-binder ratio of 0.35 and the total binder content of 550 kg/m(3). The control mixture contained only Portland cement (PC) as the binder while the remaining mixtures having binary and ternary blends of PC, FA, and SF. Properties that include compressive strength and ultrasonic pulse velocity, chloride ion penetration, gas permeability, water absorption by total immersion and by capillary absorption were investigated at two curing ages of 28 and 56 days. Test results have showed that incorporating the mineral admixtures enhanced significantly the permeability characteristics. Moreover, it was observed that the compressive strength of the SCLWCs with SF was much higher than those of the control concrete. (C) 2014 Elsevier Ltd. All rights reserved

Safety analysis of a corn processing industry by energy trace and barrier analysis method: a case study

Background and aims  &nbsp;Each year many people die from accidents at work. Enormous costs of these accidents have forced specialists looking for ways to prevention of accidents. This study focuses on evaluation the safety of glucose production unit by energy trace and barrier analysis (ETBA) and present approaches to prevention of accidents.   Methods   Steps to perform ETBAmethod was completed in the field study. Data was collected by interview with workers and supervisors, document surveys and direct observations. 41 ETBA worksheets were completed for seven fold parts of production unit. Most unacceptable risks were   found in starch site.   Results  &nbsp;Findings showed that unwanted flow of potential energies create the most unacceptable risks in production unit. We concluded that the human factors would play main roll  in reduction of risks and control hazards. Also, administrative controls are suggested, especially  establishment of repairing and preventive maintenance system, organizing team for investigation  and record keeping of accidents, reporting and scientific analyzing of accidents and incidents  would reduce the total risk of industry.   Conclusion It will be useful to use the techniques that research human role in accidents associated with ETBA method