FE investigation of failure modes at the soffit of a steel plated RC beam

In recent decades, a significant research has been carried out towards understanding the behaviour of plated beam. Initially designed to achieve a desired capacity, the plated beams prematurely fail in undesirable modes of failure, such as debonding and peeling. The uncertainty related with such modes of failure poses a real challenge towards quantifying them. This field is far from being clearly understood. Therefore, an attempt is made in this thesis to accurately predict the behaviour of adhesively plated beams. [Continues.

Biomechanical behaviour - Anisotropy of eye cornea through experimental strip tests

Abstract With the advent of research it was identified that material properties are responsible for errors in tonometry pressure (referred to as Goldmann IOP or IOPG) with the stiffening of a composite structure of corneal tissue in particular. Strip tensile tests are conducted to determine their stress–strain relationship for the purpose to study the behaviour of material properties of cornea. Specimens are taken from the superior–inferior (vertical) and temporal– nasal (horizontal) directions. Testing is performed on an Instron machine, under different rate of loading conditions. First set of experiment, with single strain rate, is executed on eyes having random population. While the second set of experiment is executed on eyes of the same animal in both directions, and different strain rates are applied each specimen. Relatively, the first set of experiment is found to be slightly different and less accurate. In general, it is found that the vertical specimen is 34% on an average stiffer than the horizontal specimen compared to Kampmeier et al. of 20% (studied in 2000) and Defu Wang of 15% (studied in 2007). Curve fitting coefficients are also evaluated for 4–degree polynomial. The anisotropy is evident by plotting the ratio of E–tangent value of vertical Ev and horizontal Eh against stresses with individual strain rates. The value of Ev/Eh increases with slightly slow rate with stresses as compared to achieved through slow strain rates.</jats:p

A Study of Performance of Regulated Market and Its Benefits

The main objective of regulating the market is protecting the interest of producer, sellers increase the standards of the local Markets where the first exchange of the commodities take its place. In order to attain and reach the object of each regulated markets hence the establishment of Market committees are executed which is consisting of the representatives of the cultivators, dealers, locals’ bodies, co-operative, shops, sellers, and the selected state government candidates. Producers are mostly considered in these committees. The committee of market, would consist of (12) to (18) members, subjected to the size of the market. Regulated Markets have many advantages and benefits such as the growers are encouraged to bring their produce straight to the markets, Growers are protected from the manipulation of market functionaries, Market costs are definite and obligatory, Growers are ensured with better prices, Obtainability of the staffs for the disbursement of disputes, Facilities like platforms for the sale transactions, parking storage facilities, rest houses, and etc. are made available, Growers have accessibility to up-to-date, market information and Marketing costs are lowered and the producer share in consumer will increase. The regulated market functions are to deliver marketing facilitates, marketing of notified crops regulation, as well as to create a yards of the required infrastructural facilities

Interferon alpha for chronic Hepatitis D

Background: Hepatitis D virus is a small defective RNA virus that requires the presence of hepatitis B virus infection to infect a person. Hepatitis D is a difficult-to-treat infection. Several clinical trials have been published on the efficacy of interferon alpha for hepatitis D virus (HDV) infection. However, there are few randomised trials evaluating the effects of interferon alpha, and it is difficult to judge any benefit of this intervention from the individual trials. Objectives: To evaluate the beneficial and harmful effects of interferon alpha for Patients with chronic hepatitis D. Search methods: We identified relevant for the review randomised clinical trials by electronic searches in the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until May 2011. We also checked the bibliographic references of identified randomised trials, textbooks, and review articles in order to find randomised trials not identified by the electronic searches. Selection criteria: Randomised clinical trials evaluating interferon alpha versus placebo or no intervention for Patients with chronic hepatitis D infection. Data collection and analysis: Two authors assessed the trials and extracted data on mortality, virologic, biochemical, and histological response as well as adverse events at end of treatment and six months or more after completing treatment. The analyses were performed using the intention-to-treat principle including all randomised participants irrespective of follow-up. Drop-outs, withdrawals, and non-compliance were considered as treatment failures. Data were analysed with fixed- and random-effects models. Reported results were based on fixed-effect model except in cases where statistical significance varied between the two models. Main results: Six randomised trials fulfilled the inclusion criteria. Two hundred and one randomised participants (male = 174) were included. The risk of bias in all the included trials was high. Five trials compared interferon alpha with no treatment in the control group. One of these trials had two treatment arms with a higher dose and lower dose of interferon alpha and a no-treatment control group. We analysed both treatment regimens as a single group in a primary analysis and as separate groups in the subgroup analysis of different interferon dosages. The sixth trial compared only a higher dose of interferon alpha with a lower dose. Meta-analysis of five trials comparing interferon alpha with no-treatment control group included 169 participants. There were seven drop-outs in the treatment group and nine in the control group. One Patient out of 92 (1.1%) died in the interferon alpha group compared with zero out of 77 (0.0%) in the no-intervention control group (risk ratio (RR)) 3.00, 95% confidence interval (CI) 0.14 to 66.5). Interferon alpha led to failure of end of treatment virological response in 62/92 (67.4%) of the Patients compared with 71/77 (92.2%) in the untreated controls (RR 0.76, 95% CI 0.66 to 0.87, P = 0.0001 by fixed-effect model and RR 0.71, 95% CI 0.43 to 1.16, P = 0.17 by random-effects model). Failure of normalisation of alanine aminotransferase (ALT) at the end of treatment was seen in 60/92 (65.2%) Patients treated with interferon alpha versus 76/77 (98.7%) in the control group (RR 0.69, 95% CI 0.59 to 0.80, P \u3c 0.00001). Sustained virological response was not achieved in 76/92 (82.6%) of Patients on interferon compared with 73/77 (94.8%) of controls (RR 0.89, 95% CI 0.80 to 0.98, P = 0.02). Serum alanine aminotransferase was abnormal in 81/92 (88.0%) treated with interferon alpha Patients at six months post-treatment follow-up compared with 76/77 (98.7%) in controls (RR 0.92, 95% CI 0.84 to 0.99, P = 0.04). There was no significant histological improvement in 67/92 (72.8%) Patients treated with interferon alpha compared with 65/77 (84.4%) in controls (RR 0.86, 95% CI 0.74 to 1.00, P = 0.06). Two trials comparing a higher dose of interferon alpha with the lower dose showed no significant difference in sustained virological response (76.7% compared with 90.0%) (RR 0.85, 95% CI 0.68 to 1.07, P = 0.16). Adverse events such as flu-like symptoms, asthenia, weight loss, alopecia, thrombocytopenia, and leukopenia were reported in all these trials and the adverse events were related to interferon alpha. These were common and sometimes severe. One Patient in the treatment group was reported to have died by suicide towards the end of the study period. Authors\u27 conclusions: Interferon alpha does not seem to cure hepatitis D in most Patients. The agent seems effective in suppressing viral and liver disease activity in some Patients, but this improvement is not sustained in the majority of Patients. We cannot exclude overestimation of benefits and underestimation of harms due to high risk of bias (systematic errors) and high risk play of chance (random errors). Therefore, more randomised trials with large sample sizes and less risk of bias are needed before interferon can be recommended or refuted

The Equity Risk Premium Puzzle in Pakistan

Our study uses the consumption-based asset-pricing power utility model to test theEquity Risk Premium (ERP) puzzle in Pakistan. The study has collected monthly stock pricedata from July 1997 to December 2017 from the PSX data portal. We extracted informationabout macroeconomic factors such as inflation and risk-free interest rate from the State Bankof Pakistan. Moreover, the study used private consumption and population data from thePakistan Bureau of Statistics. The results suggest that the ERP puzzle has a strong occurrencein Pakistan, a phenomenon previously associated with only developed markets. Onedisadvantage of the present investigation is the small sample size. A longer time durationcould have reduced short-term biases. Past researchers have suggested different approachesfor solving the equity premium puzzle. For instance, some studies used improvised structuralmodels to justify the equity risk premium puzzle using macroeconomic factors

Controlled failure warning and mitigation of prematurely failing beam through adhesive

In plated beam, an adhesive is used primarily to adhere the external plate to the concrete beam to achieve a composite action. Even though some work has been found to indicate that the choice of softer adhesive increased the capacity of beam (MacDonald & Calder, 1982), relatively stiffer adhesives have been largely assumed to provide better strengthening. Largely, due to the fact that adhesive has been widely considered as an insignificant structural component towards the capacity of a composite beam; material capabilities (if not structural) of adhesive have also been ignored for further research towards studying its effects on premature failures (particularly debonding). Under mixed-mode loading, the adoption through discretisation of Cohesive Zone Model as a bulk material (indicative of adhesive component) and to simulate interfacial cracks is shown here to achieve the objectives. The outcomes of the research indicate the critical material properties of adhesive in all directions, such as stiffness, strength and crack energy, play crucial role in controlling the behaviour of modes of failure. Further, based on this study, recommendations have been proposed on the choice of adhesive type at different locations of plated beam so as to capture a failure warning and avoid catastrophic failure

Relative behaviour of premature failures in adhesively plated RC beam using controllable and existing parameters

© 2017 Elsevier Ltd Retrofitting of RC beam by gluing a steel plate at the soffit has been a widely adopted technique due to its ease of use, calculations and having minimal variations on structural aesthetics; hence, a large number of such retrofitted structures exist today. However, such structures have also failed frequently due to the formation of premature failures such as peeling and debonding. The further investigations conducted in literature indicated that such undesirable failures can be effected by a large number of geometrical and material parameters. Although, the characterisation and relative influence of such parameters on modes of failures remain unknown; as the past studies have been largely case sensitive or focussing on a small set of parameters. Therefore, to address these issues, a simple but focussed numerical model has been validated through literature for multiple modes of failures over wide range of possible parameters. Further, targeting the response of beam and its critical locations, the authors of this study suggest that the understanding of relative impact of effective parameters, in terms of beam capacity and brittleness of modes of failure, can be broadly utilised to re-evaluate the cause(s) of failure(s) through case studies, or to predict the future of retrofitted structures/beams

Numerical representation of multiple premature failures in steel-plated RC beams

© World Scientific Publishing Company.Realizing the importance of widely used technique of plating for flexural retrofitting of reinforced concrete (RC) beams and its drawbacks due to premature failure(s), present work concentrates in developing a finite element tool model capable of successfully capturing multiple premature failure modes and their corresponding behaviors. The model is simple but focused; the capability and accuracy of the results have been validated through test literature, particularly focusing on the load capacities of beams at progressive stages of failure modes; which is from crack initiation through to complete failure, such as the load of crack initiation, first crack and complete failure. Acceptable accuracy is shown in terms of crack type(s), crack patterns, sequence, location and direction of propagation through the innovative use of cohesive zone model (CZM). The model clearly explains that debonding and peeling, although originating from a same location for most cases, are extensions of different types of cracks

Vitamin-D Toxicity And Other Non-Malignant Causes Of Hypercalcemia: A Retrospective Study At A Tertiary Care Hospital In Pakistan

Background: Hypercalcemia is a common clinical problem; primary hyperparathyroidism and malignancy is commonest causes of hypercalcemia. Aetiology of hypercalcemia are changing, causes that were diseases of the past like Vitamin-D toxicity and milk alkali syndrome are observed more often. Vitamin-D deficiency is an important problem and overzealous replacement of Vitamin-D has been observed, suspected to cause toxicity. Methods: This was a retrospective review of patients admitted at the Aga Khan University Hospital from January 2008 to December 2013 with hypercalcemia. We reviewed the electronic health records for laboratory and radiological studies, and discharge summaries to establish the cause of hypercalcemia. Patients with solid tumour malignancy were excluded from the analysis. The treatment records and hospital course of patients diagnosed with Vitamin-D toxicity were also reviewed. Results: Primary hyperparathyroidism was the most common cause of hypercalcemia comprising 41 (28.2 %) patients. Vitamin-D toxicity was present in 25 (17.3%) and probable Vitamin-D toxicity 11 (7.6 %) inpatients. Vitamin-D toxicity and probable Vitamin-D toxicity together comprised 36 (24.8%) cases. Other causes of hypercalcemia included multiple myeloma 18 (12.4%) patients, tuberculosis 6 (4.1%) patients, chronic kidney disease6 (4.1%) cases, sarcoidosis 4 (2.7%) and lymphoma 3 (2.0%) patients. In 29(20%) patients a cause of hypercalcemia could not be determined and were labelled as undiagnosed cases. Conclusion: Vitamin-D toxicity was the second commonest cause of hypercalcemia after primary hyperparathyroidism. Knowledge of the prevalent and emerging causes of hypercalcemia is important for prompt diagnosis and treatment.