Theoretical and experimental investigation of thin-walled structural elements under various load actions

Thin-walled structural forms exhibit in their behaviour under compressive actions, features normally suppressed by the heavy section outlines used in hot rolled constructions. Thus, over-all instability under a combination of torsion and flexure, is obtained in a much wider range than in hot rolled sections; and local instability, i.e., buckling of the plate components (flange or web), disregarded in hot rolled construction becomes one of the chief characteristics of thin-walled behaviour. The subject-matter of the thesis deals with these two forms of instability both theoretically and experimentally. The contents of the thesis are divided into 4 main parts, each part being further subdivided into convenient sections. Part I presents a critical review of published work relevant to: (i) over-all instability in torsion-flexure, and (ii) local instability of plate components of struts in flexure. This reveals the absence of theoretical treatment of: (i) mixed boundary conditions in torsional-flexural buckling, e.g., a hinged end strut with warping restraint, and (ii) the determination of the critical stress in local buckling of plates subjected to linearly varying compressive load actions, applicable to the plate components of structural sections subjected to eccentric axial loading. There also appears to be a scarcity of experimental investigations in this latter field. The review is followed by the theoretical analysis presented in Part II. This develops an iterative method of general application to problems of instability. The method is first applied to the derivation of the torsional-flexural buckling load for mixed boundary conditions not hitherto solved, such as the combination of hinged ends with warping restraint. The second application of the iteration method is the derivation of the local buckling strength of plates elastically supported along one longitudinal edge and free along the other. The loading for these boundary conditions, not hitherto considered in published literature, is an axial compressive action linearly varying across the width of the plate. This is applied to assess the strength in local instability of eccentrically loaded thin-walled channel sections. The experimental work described in Part III presents the results of some 190 strut tests to destruction. These consisted of equal and unequal angle and channel specimens of 65 S.W.P. Aluminium Alloy, 3 inches to 132 inches long. The tests were designed to investigate the effects on over-all and local buckling of the variation of load eccentricity, length, section profile and method of manufacture (cold formed versus extruded). In Part IV the results obtained are analysed and compared with the theory showing good agreement. The textual part of the thesis concludes with a Summary which draws attention to the main features of instability conditions investigated, as indicated by the theory and confirmed by the experimental work. The thesis concludes with a Bibliography, followed by 7 Appendices in which the details of various aspects of the work are presented

Savings and Credit Cooperative Societies (SCCs): A Panacea to Accessing Funds for Housing Development to Workers of Public Institutions in Nigeria

This paper assesses the impact of Savings and Credit Cooperative Societies (SCCS) as a panacea to providing funds for housing development to workers in Nigeria public service. The Institute of Agricultural Research (IAR) Ahmadu Bello University, Zaria-Nigeria was used as a case study for the research. Questionnaires were administered to 82 staff of the institution that belongs to the institute cooperative society (IAR Rangwame Multipurpose Cooperative Society (IRMCS)) and a separate designed questionnaire was given to 3 officials of the society. Descriptive analysis, chi-square test and cooperators satisfaction index (CSI) was used for analyzing the data collected. The findings from the analysis showed that 7(8.5%) of IRMCS members have bare lands, 11(13.4%) have their houses under construction and 5(6.1%) have completed their houses while the remaining 59 members did not benefited IRMCS housing loan. The CSI on each attribute of “interest rate”, “affordability”, “transaction cost”, “availability” and “collateral” for cooperative loan are greater than 4 (close to 5) except for “availability” which is close to 4 and the aggregated CSI for all attributes is 4.17 which is also close to 5 is very high compared to National Housing Fund (NHF) CSI’s on each attributes which are all less than 2.7 with an aggregated CSI of 2.5. Also, the cooperators range of dissatisfaction index (RDI) was determined and it was found that cooperative loan had the lowest (0.832) against NHF of 2.41 and this indicates that IRMCS members are well satisfied with cooperative loans compared to the NHF. The paper concludes that SCCS can be a viable instrument in impacting positively towards funding housing projects to workers of public institutions. Keywords: SCCS, Informal sources of finance, Housing, NHF, CSI, RD

Sustainable release of propranolol hydrochloride laden with biconjugated-ufasomes chitosan hydrogel attenuates cisplatin-induced sciatic nerve damage in in vitro/in vivo evaluation

Peripheral nerve injuries significantly impact patients’ quality of life and poor functional recovery. Chitosan–ufasomes (CTS–UFAs) exhibit biomimetic features, making them a viable choice for developing novel transdermal delivery for neural repair. This study aimed to investigate the role of CTS–UFAs loaded with the propranolol HCl (PRO) as a model drug in enhancing sciatica in cisplatin-induced sciatic nerve damage in rats. Hence, PRO–UFAs were primed, embedding either span 20 or 60 together with oleic acid and cholesterol using a thin-film hydration process based on full factorial design (2(4)). The influence of formulation factors on UFAs’ physicochemical characteristics and the optimum formulation selection were investigated using Design-Expert(®) software. Based on the optimal UFA formulation, PRO–CTS–UFAs were constructed and characterized using transmission electron microscopy, stability studies, and ex vivo permeation. In vivo trials on rats with a sciatic nerve injury tested the efficacy of PRO–CTS–UFA and PRO–UFA transdermal hydrogels, PRO solution, compared to normal rats. Additionally, oxidative stress and specific apoptotic biomarkers were assessed, supported by a sciatic nerve histopathological study. PRO–UFAs and PRO–CTS–UFAs disclosed entrapment efficiency of 82.72 ± 2.33% and 85.32 ± 2.65%, a particle size of 317.22 ± 6.43 and 336.12 ± 4.9 nm, ζ potential of −62.06 ± 0.07 and 65.24 ± 0.10 mV, and accumulatively released 70.95 ± 8.14% and 64.03 ± 1.9% PRO within 6 h, respectively. Moreover, PRO–CTS–UFAs significantly restored sciatic nerve structure, inhibited the cisplatin-dependent increase in peripheral myelin 22 gene expression and MDA levels, and further re-established sciatic nerve GSH and CAT content. Furthermore, they elicited MBP re-expression, BCL-2 mild expression, and inhibited TNF-α expression. Briefly, our findings proposed that CTS–UFAs are promising to enhance PRO transdermal delivery to manage sciatic nerve damage

Polyorchidism: case report and literature review

Polyorchidism is a rare congenital anomaly frequently associated with maldescent testis, hernia, and torsion. Reports in the literature show an increased risk of testicular malignancy in the presence of polyorchidism. This entity has characteristic sonographic features and the diagnosis is often made on the basis of sonography. A conservative approach is the treatment of choice in uncomplicated cases. We report a male of 26-years old with 2 testicles in right side diagnosed by ultrasound. A brief history and review of the literature is also presente

Egyptian consensus on treat-to-target approach for osteoporosis: a clinical practice guideline from the Egyptian Academy of bone health and metabolic bone diseases

Background: This study was carried out to achieve an Egyptian expert consensus on a treat-to-target managementstrategy for osteoporosis using Delphi technique. A scientific committee identified researchers and clinicians with expertise in osteoporosis in Egypt. Delphi process was implemented (2 rounds) to establish a consensus on 15 clinical standards: (1) concept, (2) diagnosis, (3) case identification, (4) whom to treat, (5) who should treat?, (6) case stratification and intervention thresholds, (7) falls risk, (8) investigations, (9) treatment target, (10) management, (11) optimum treatment duration, (12) monitoring, (13) drug holiday, (14) osteoporosis in men, and (15) post-fracture care and fracture liaison service. Results: The surveys were sent to an expert panel (n = 25), of whom 24 participated in the two rounds. Respondents were drawn from different governorates and health centres across Egypt including the Ministry of Health. Most of the participants were rheumatologists (76%), followed by internists (8%), orthopaedic doctors (4%), rehabilitation doctors (4%), primary care (4%), and ortho-geriatrics (4%) physicians. Seventy-two recommendations, categorised into 15 sections, were obtained. Agreement with the recommendations (rank 7–9) ranged from 83.4 to 100%. Consensus was reached (i.e. ≥ 75% of respondents strongly agreed or agreed) on the wording of all 15 clinical standards identified by the scientific committee. An algorithm for the management of postmenopausal osteoporosis has been suggested. Conclusion: A wide and representative panel of experts established a consensus regarding the management of osteoporosis in Egypt. The developed guidelines provide a comprehensive approach to the assessment and management of osteoporosis for all Egyptian healthcare professionals who are involved in its management

Sustainable environmental geotechnics practices for a green economy

The revitalisation of the global economy after the Covid-19 era presents environmental geotechnics with the opportunity to reinforce the need for a change in paradigm towards a green, circular economy and to promote aggressively the use and development of sustainable technologies and management practices. This paper aims to assist in this effort by concentrating on several thematic areas where sustainability solutions and future improvements are sought. These include the re-entry of construction and demolition of wastes, excavated materials, industrial wastes and marine sediments into the production cycle and the reuse of existing foundations. Despite the recent trend in advanced countries towards recycling and waste-to-energy thermal treatment, landfills still constitute the most common municipal solid waste management practice, especially in low-and-middle-income countries, and technological solutions to improve their environmental footprint are hereby presented. At the same time, remediation solutions are required to address the multitude of contaminated sites worldwide. Advanced developments that incorporate environmental, economic and social dimensions are expounded by the authors, together with sustainable ground improvement solutions for infrastructure projects conducted in soft and weak soils. The topic of thermo-active geostructures concludes this paper, where, apart from their infrastructure utility, these structures have the potential to contribute to the renewable energy source.Published versionThe second author would like to acknowledge the support of the Office of the Associate Provost for Research and Academic Development at Abu Dhabi University, UAE through grant19300540

Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy

Background A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets. Methods Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis. Results A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001). Conclusion We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty