Effect of material properties on ductility of reinforced concrete beams

Reinforced concrete (RC) is one of the most important building materials and is widely used in civil engineering structures. The constituents of reinforced concrete such as concrete and steel are very complex due to their different mechanical properties. The stress-strain behavior of concrete under short term compression loading is considered parabolic and that of the steel is elastic plastic. Concrete and reinforcing steel are represented by separate material models that are combined together to describe the behavior of the RC beam sections. The end displacements of the steel element are assumed to be compatible with the boundary displacements of the concrete element which implied perfect bond between them. This paper presents the effects of materials properties such as concrete compressive strength, yield strength of steel and reinforcement content on the curvature ductility of singly reinforced concrete beams as well as doubly reinforced concrete beams. From the analyses, it is observed that the ductility of a singly RC beam decreases as the tension steel content is increased, and the presence of compression steel increases the ductility significantly. For the same reinforcement content the increase in compressive strength of concrete increases curvature ductility of reinforced concrete section and for a doubly reinforced section rate of increase of curvature is more than that of a singly reinforced section. However, the moment ratio increases at a relatively slow rate than that of singly reinforced beams. On the other hand the ductility of RC beams decreases as the strength of reinforcement is increased

Innovation in engineering consultancy: a case for competitive advantage

The internationalisation of the engineering consultancy services brings new challenges to its competitiveness. Service innovation is the way to enhance competitiveness. Although competitive innovation in the 1990s was achieved by information and communication technologies adoption, it is no longer sustainable without the combination of entrepreneurship, learning, sharing, knowledge and creativity, and by using information and communication technologies as a tool. The firm and the individual face challenges from external perceptions, internal beliefs, institutional legacies and organisation cultural misalignments. This paper proposes a knowledge-based model for re-engineering the firm with a learning culture. If engineering consultancy is a knowledge-based business whose asset is the employees, then the firm has to manage knowledge in an organisational learning and sharing context for the innovation purpose. Knowledge management with a human resource strategy for learning is a means to leverage the know-how, experience and judgment of the pool of highly qualified labour to achieve the innovation objective by replacing irrelevant work routines with dynamic ones

Stakeholders assessment of constraints to project delivery in the Nigerian construction industry

The central goal of construction stakeholders is to successfully deliver projects to stated objective (s). However, for decades, construction projects have been plagued by perennial constraints of cost and time overruns, poor quality, and lack of sustainability. The objective of this paper is to identify and assess the constraints to construction project delivery, and to recommend solutions to enhance project performance. This paper adopted both quantitative and qualitative methods to establish the constraints in the Nigerian construction industry. A pilot survey and literature reviewed revealed a total of fifty (50) construction constraints, which were further classified into eight (8) major groups. Well-structured questionnaires were administered to construction stakeholders (client, consultant and contractor) in Abuja, the federal capital city of Nigeria. Relative Importance Index (RII) was used to analyze the data using Likert scale. The results suggest that cost/time overrun related factors (inability to reduce project cost), Stakeholders interactive-related factors (inability to establish client value system), Client-related factors (Delay in interim payment and finance problem), and Labor/ material-related factors (escalation of material prices and materials quality variability) are the most prevalent constraints in the Nigerian construction environment. To mitigate the effects of these challenges, it is suggested that a formal innovative approach should be used by stakeholders to address the problems of poor communication, high project cost, and delay. Clients should also take measures to provide adequate funding and should promptly honor interim certificates

Endovascular Aneurysm Repair (EVAR) for infra-renal Abdominal Aortic Aneurysm (AAA) under local anaesthesia - initial experience in Hospital Kuala Lumpur

This is our initial report on the first 4 cases of infra-renal abdominal aortic aneurysms undergoing Endovascular Aneurysm Repair (EVAR) with local anaesthesia, controlled sedation and monitoring by an anaesthetist. All 4 patients were males with a mean age of 66.7 years. Only one (1) required ICU stay of 2 days for cardiac monitoring due to bradycardia and transient hypotension post procedure. No mortality or major post operative morbidity was recorded and the mean hospital stay post procedure was 3.5 days (range 2-5 days)

Retention of knowledge following training of students in basic trauma life support

Introduction: In the course of their undergraduate training at the International Medical University, students receive a Basic Trauma Life Support course. Objective: We wanted to test the long-term retention of knowledge (after 16 months) of third year medical students who had received training in Basic Trauma Life Support Method: To assess the retention of knowledge one cohort of students who received the training course were tested again 16 months later using the same 30 question One Best Answer quiz. Results: Seventy-three students who underwent the course sat for the Retention test. The number of students who passed the Retention test was not significantly different from the test taken immediately after the course. The mean scores, 62.5% and 59.5% respectively, were however significantly different. Conclusion: Our study involves a relatively long interval between the course and retention of knowledge test shows encouraging results

Adherence of Streptococcus pneumoniae and expression analysis of neuraminidase gene (NanA and NanB) after interaction of A549 human lung epithelial cells with pneumococcal strains of various serotypes

Aims: Streptococcus pneumoniae is the most common bacterial respiratory pathogen that can lead to invasive diseases such as pneumonia, bacteremia, and meningitis. The interaction of S. pneumoniae with host respiratory epithelial cells is crucial in the colonization of human respiratory tract and involve in the virulence. The aim of the study is to investigate the adherence of S. pneumoniae and the effect of serotypic variation on neuraminidase genes (NanA and NanB) after interaction of A549 human lung epithelial cells with S. pneumoniae serotypes. Methodology and results: Six different serotypes of S. pneumoniae were used (1, 3, 5, 19F, 23F, and 14). A549 human lung epithelial cells were inoculated with pneumococcal strains of different serotype for 3 hours. The number of adherent bacteria was determined by serial dilution followed by spread plate technique on tryptic soy agar supplemented with 5% sheep blood. Bacterial RNA was harvested from the infected A549 cells. The differential expression level of neuraminidases was observed by quantitative real-time PCR (qRT-PCR). Based on bacterial adherence assay, serotype 14 showed highest adherence, meanwhile, serotype 23F showed lowest adherence. This suggests that serotype 14 has a better affinity to adhere to A549 cells as compared to serotype 23F. Higher NanA gene expression was observed in serotype 5, 23F and 19F, while lower expression in serotype 14. In contrast, NanB gene shows low-level expression in serotype 23F and 19F, while higher expression in serotype 14. This postulates that NanA and NanB gene may have different functions in the pathogenesis of S. pneumoniae. Conclusion, significance and impact of study: Our finding on differential expression of neuraminidase gene of S. pneumoniae of various serotypes on A549 cells might give a better understanding of host pathogen interaction between bacteria serotypes and host cell