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تتميز عائلة أكاسيد البيروفسكيت ومشتقاتها مثل سلسلة ردلسدين_بوبر (Ruddledsen -popper) التي تأخذ الصيغة العامة An+1BnO3n+1، بالعديد من الخصائص الهامة كالخواص الكهربائية ، والمغناطيسية ، والبصرية إضافة إلى المرونة التي تكسبها القدرة على استيعاب أي كاتيون في المواقع A و B وبالتالي إمكانية القيام بالاستبدال في هذه المواقع الأمر الذي يؤدي لإمكانية التعديل على خواصها الفيزيائية ومنه تطوير مواد بخواص جديدة. نظراً لذلك قمنا في هذا البحث باصطناع المركب Sr2PbO4 والذي يتبلور وفق البنية المعينية(Orthorhombic) لأول مرة بطريقة الترسيب المشترك و المركب Sr2Pb0.75Bi0.25O4 بإجراء الاستبدال الجزئي للرصاص بعنصر البزموت بنسبةx=0.25 ، وبدراسة مخططات انعراج الأشعة السينية XRD تبين أنها تتبلور وفق البنية المعينية (مجموعة الفراغ: Pbam) بعد إجراء الأستبدال مع انخفاض طفيف في الأبعاد البلورية a،c ونستدل من هذا الأنخفاض أن غالبية عنصر البزموت دخل بدرجة أكسدة +5 كما تمت دراسة بعض الخواص الكهربائية بجهاز الmeter LCR بتغيير فرق الكمون بين اللبوسين بين -0.5 فولط و+0.5 فولط وقياس التيار المار في العينة عند التردد 1 كيلوهرتز إذ لوحظ تغير في الناقلية الكهربائية وكما تبين من الدراسة البنيوية أن غالبية عنصر البزموت بدرجة الأكسدة +5 وبالتالي هذا سيؤدي لمشاركة الإلكترونات الفائضة بعصابة الناقلية .

تعد الأكاسيد ركيزة أساس في الثورة التكنولوجية من الإلكترونيات إلى النانو، لهذا فقد لقيت عناية خاصة من قبل الباحثين في كيمياء المواد بسبب العدد الكبير من هذه المركبات التي تلعب دوراً هاماً في الصناعات ، كما أنها عائلات واسعة تتنوع خصائصها الفيزيائية من الناقلية الفائقة، والمغناطيسية. ومن بين هذه العائلات نجد عائلة Perovskites .هذه المركبات عبارة عن أكاسيد معدنية تملك الصيغة ABO3 ، وهي تشمل العديد من المركبات التي تملك خواص ملفتة للانتباه ذات الأهمية الكبيرة في الالكترونيات الدقيقة والاتصالات السلكية واللاسلكية ، وتعد المركبات المشتقة من البنية البيروفسكيتيّة (بنية طبقية) التي تسمى بسلسلة رادلسدين وبوبير المكون الأساسي لخلايا الأكاسيد الصلبة إذ تم في هذه الدراسة اصطناع أكاسيد جديدة تنتمي لسلسلة رادلسدين وبوبير((An+1 Bn O3n+1، حضرت باستخدام الطريقتين، الطريقة السيراميكية وطريقة السول- جل. وتم دراسة تأثير الاستبدال الجزئي للكوبالت في الشبكة البلورية بالعنصر الانتقالي الكروم بنسب إشابة مختلفة.وأظهرت نتائج حيود الأشعة السينية بأن الأكاسيد المحضرة تتبلور وفق البنية البلوريةTetragonal ضمن النظام الفراغيI4/mmm عندn=1 وانخفاض ثوابت الشبكة a وb وازدياد c وبالتالي زيادة حجم وحدة الخلية .

Background: To evaluate the clinical outcomes and satisfaction of patients following laparoscopic Heller myotomy for achalasia cardia in four tertiary centers. Methods: Fifty-five patients with achalasia cardia who underwent laparoscopic Heller myotomy between 2010 and 2019 were enrolled. The adverse events and clinical outcomes were analyzed. Overall patient satisfaction was also reviewed. Results: The mean operative time was 144.1 ± 38.33 min with no conversions to open surgery in this series. Intraoperative adverse events occurred in 7 (12.7%) patients including oesophageal mucosal perforation (n = 4), superficial liver injury (n = 1), minor bleeding from gastro-oesophageal fat pad (n = 1) & aspiration during induction requiring bronchoscopy (n = 1). Mean time to normal diet intake was 3.2 ± 2.20 days. Mean postoperative stay was 4.9 ± 4.30 days and majority of patients (n = 46; 83.6%) returned to normal daily activities within 2 weeks after surgery. The mean follow-up duration was 18.8 ± 13.56 months. Overall, clinical success (Eckardt ≤ 3) was achieved in all 55 (100%) patients, with significant improvements observed in all elements of the Eckardt score. Thirty-seven (67.3%) patients had complete resolution of dysphagia while the remaining 18 (32.7%) patients had some occasional dysphagia that was tolerable and did not require re-intervention. Nevertheless, all patients reported either very satisfied or satisfied and would recommend the procedure to another person. Conclusions: Laparoscopic Heller myotomy and anterior Dor is both safe and effective as a definitive treatment for treating achalasia cardia. It does have a low rate of oesophageal perforation but overall has a high degree of patient satisfaction with minimal complications.

The bending moment of tunnel lining can be influenced by non-uniform ground pressures and joint eccentricities. Influence of joint interaction that induces flexural moment behaviour in segmental tunnel lining was investigated for the project Circle Line Stage 3 (C852), Serangoon Interchange Station. By considering behaviour of segment joint (which can affects the tunnel circumferential and longitudinal safety in overall), the tunnel lining behaviour and displacement of the ground surrounding the tunnel were evaluated. The segment joint modelling in simplified dual-jointed model and in fully soil-tunnel model were developed to assess the effect of segment joint on the overall tunnel response. Ground deformation or settlement trough at the ground surface resulted from the effect of tunnel construction and interaction between soil, tunnel, segment joints and ring joints was predicted. Results showed that with different use of segment joints give different longitudinal settlement. Hinge-nonlinear model together with separated rings model lead to the highest resemblance of surface settlement pattern to the field data when compare to tie model.

Human resource management framework being one of the issue across global construction industries. It is a major concern in the construction industry because inefficiency, delay and cost from construction work could be affected and causing great losses to individuals and organizations. Therefore, resource management framework is changing the way resource management can be approached. Most of the construction companies around the world are implementing human resource management systems to reduce cost, eliminate delaying project, and to provide an efficient framework in their construction site. The objective of this paper is to investigate the effectiveness of implementing human resource management framework in construction site. The methodology included is a combination of literature review, market studies and detailed questionnaire survey before starting the actual survey, a pilot study for this questionnaire was done, which confirms its acceptance. Based on findings from the researcher, most of the company and contractor firms have awareness about management of resource at construction site as human resource management is a major concern on construction industries.

Shipyard industry is one of the growing industry in Malaysia. There is still a lot of room for improvement with regards to the safety aspects within the industry. This study presents the finding of a survey on the safety management in shipyard operation of class C and D in Peninsular Malaysia registered with Ministry of Finance Malaysia. Shipyard operation is considered a hazardous job. Most of the cases were due to fall from height, fire and explosion. Similar accidents happened in South Korea, where 8 fatalities and 31 injuries were reported in January to August 2017. The accidents were due to crane collapsed and explosion during welding works inside a hull of a Liquefied Petroleum Gas (LPG) carrier. This paper aims to study the Health, Safety and Environment Management System (HSEMS) of shipyard operations in Malaysia particularly in Class C and Class D shipyard. This study was conducted using a survey method following the Glenn D’s equation. The survey was targeted at the people who are involved in the industry including the staffs of clients, consultants and contractors. The findings of this study show that almost all the shipyards of Class C and D have HSEMS in placed but some are incomplete. Accidents still happen in the Malaysian shipyard industry from time to time. The gaps in the HSEMS that lead to the accident are highlighted in this paper. Nearly 10% of Class C and D shipyards do not have clear HSE Policy and this one of possible causes of accidents due to low priority given to HSE matters in this particular Class C and D shipyard.

The purpose of this research study was to identify Good China Steel Manufacturer for Industry. Since 1990s, China’s Steel manufacture rapidly improve the output of the Steel Supply. In 2003, accumulated annual production by China’s Steel Manufacture exceeding 200million tons of Steel surpass others traditional Steel Manufacture likely Western Europe, India and Japanese Steel Manufacture. In China, there are Steel Manufacture that capable to produce the Steel Material follow World Class quality similar with reputable steel manufacture in Japan and Western Europe, however due to people general sceptical opinion on the China product, people perception that all China product is low quality without proper investigate on their capability and ability to supply the Steel Material for industry. In the project that related to steel product i.e Steel Bridge, offshore steel Jacket and Platform, pipeline, 40%-50% of Contract price is liaise with procurement of material. Utilizing China Steel Product envisage potential cost saving of 10%-20% to the overall Project cost that give advantage for both Contractor and Customer in reducing the overall cost of project. This paper aims to outline a research project for developing both information and technical requirements to identify good China Steel Manufacture via literature review, questionnaire survey, focus group, and audit report by reputable organization. The project results, will act as solid platform for Contractor and vendor to identify potential Steel Vendor for their project. It will support the decision-making process with respect to, quality, safety enhancement and assurance of quality to utilize China Steel Product for a project.

Necessity of construction automation through BIM framework could no longer be set aside if we were to remain relevant and con-current in the ever-changing, technology-driven construction practices. The functions of construction safety management, i.e., hazard identification, assessment and control for construction works could certainly benefit from this technology through safety work automation which enhances the effectiveness and efficiency of the required safety processes. This paper aims to outline a research project for developing both information and technical requirements for BIM-based system via literature review, questionnaire survey, focus group, and prototype realization. The project results, to be validated by real projects, will act as solid platform for developing working model that can be employed at various project settings and safety circumstances. It will support the decision-making process with respect to safety enhancement and accident mitigation at the construction site.

Construction of tunnel results in ground movements with a settlement trough which is well described by a Gaussian distribution curve. For near surface settlements, it was established that the trough width i is an approximately linear function of the tunnel depth zo in relation to a trough width parameter K and broadly independent of tunnel construction method and tunnel diameter (except for very shallow tunnels where the cover to diameter ratio is less than one). The choice of an appropriate value of K may require some judgement, since it depends on whether the ground is primarily cohesive or frictional. Published literatures recommended that for practical purposes K could be taken as 0.5 for tunnels in clays and 0.25 for tunnels in sands and gravels. This paper discusses the evaluation of trough width parameter which has not been studied much for typical soil types encountered in the Klang Valley of Malaysia (e.g. Kenny Hill formation weathered materials, granitic soil, alluvium, etc.) of which are commonly in cohesive-frictional nature. The main objective of study is to investigate, using numerical method, the arbitrary relationship of the trough width parameter for different soil types in terms of its effective shear strength parameters and stiffness parameter. A parametric study was carried out to identify parameter(s) which have a significant influence on the settlement trough width and simple equation is presented subsequently for estimating appropriate K values for empirical calculation. This study has excluded two-layered system of different geology where, for example, a tunnel in Kenny Hill formation is overlain by significant thickness of alluvium deposits. Preliminary findings based on numerical analysis showed some promising results. Effort to continually build up the field database to further refine the deduced relationship for the surface settlement trough width parameter is in progress over the course of construction for Klang Valley MRT tunnels.

Construction Industry is a high risk industry and widely recognised as one of most hazardous occupation in the world. The statistic of accidents in Malaysia give us a picture that Malaysian construction industry is one of the dangerous sectors that need a drastic overhaul from the current site safety practices. This paper describes a review of the accident causes occurred in construction site by various researchers during the last twenty (20) years. This paper discusses the accident causes in Malaysia construction works and entire world. The data collected shows that variety of accident causes in construction industry either in Malaysia or other country.

Despite the improvement in utilization of project management tools and techniques over the years, there are still many projects failed to meet their objectives. Early warning signs becomes one of the concepts used to detect the potential cause of failure in a project. Early warning is defined by signals, which can be seen variously as an expression, indication, a proof, or a sign of existence of some future negative issues. In recent years, several researches regarding early warning signs have been proposed by many authors, varying from project assessment stage in detecting the signs, methodology in conduction early warning sign research and the type of the projects tested. This article presents a review of related work on early warning signs of project failure to give conceptual insights on what early warning is.

There is a trend in Malaysia and Singapore, engineers tend to model the effect of TBM tunneling or deep excavation to the adjacent piles in 2D model. In the 2D model, the pile is modelled using embedded row pile element which is a 1-D element. The user is allowed to input the pile spacing in out-of-plane direction. This gives an impression to engineers the embedded pile row element is able to model the pile which virtually is a 3D problem. It is reported by Sluis (2014) that the application of embedded pile row element is limited to 8D of pile length. It is also reported that the 2D model overestimates the axial load in pile and the shear force and bending moment at pile top and it is not realistic in comparison to 3D model. In this paper, the centrifuge results of single pile and 6-pile group - tunneling problem carried out in NUS (National University of Singapore) are back-analysed with Midas GTS 3D and a 2D program. In a separate case study, pile groups adjacent to a deep excavation is modelled by 3D and 2D program. This paper compares the deflection and forces in piles in 2D and 3D models.

For almost two decades, distributed optical fibre sensors are well-known for an alternative to conventional instrumentation in geotechnical engineering applications. However, the technology is yet to be fully implemented due to uncertainties of attachment method or the best way to deploy optical fibre for geo-structure health monitoring. Thus, a project of a 1g model of soil slope was intiated and was constructed with three layers of optical fibre that were horizontally embedded in the soil slope mass in order to observe strain development due to a surcharge load. The strain mobilizations were measured by using Brillouin Optical Time-Domain Analysis (BOTDA) sensing system during the incremental loading on the slope crest until a failure feature had been initiated. The aim of study is to evaluate the development of horizontal strains from Brillouin-based optical fibre sensor subjected to soil slope deformation which lead to slope failures. The results showed that the measurands of optical fibre were highly accumulated at the position of 0.3m depth from the slope crest. The development of high strain at this position was because of soil-fibre interaction to the overburden imposed load in perpendicular direction of optical fibre placement. Therefore, it can be concluded that the optical fibre strain in the soil-strain field were well-responded to the particle soil movement. In addition, the significant trend of positive strain curves were illustrated when the soil was under compression due to external load from a surcharge load plus self-weight of the soil material.

For today’s demands in underground infrastructure, geotechnical considerations are gaining prominence, emphasizing the resolution of complex problems through numerical modeling and soil-structure interaction analysis. There is a clear trend shifting away from two-dimensional (2-D) plane strain or axisymmetric idealizations to the comprehensive analysis of full three-dimensional (3-D) models. However, despite the inclination towards 3-D modeling of tunnels, establishing a realistic 3-D model for this purpose remains a timeconsuming process. This typically involves multiple iterative and incremental phases, essential for gaining deeper insights into the three-dimensional nature of the problem. Beyond selecting an appropriate constitutive soil model, realistically finite element modeling and accurate simulation of the tunneling process are of paramount importance. This study focuses on the development of a practical full 3-D model and simulation of the Earth Pressure Balance (EPB) shield tunneling process using the finite element code PLAXIS 3D. The numerical model incorporates tunnel boring machine driving data recorded during tunnel construction and is validated through back-analysis of field measurements of tunneling-induced ground surface settlements. The findings demonstrate that numerical simulation can realistically reproduce the main characteristics of EPB shield tunneling. The study recommends adopting non-linear face pressures with depth based on the analysis of tunneling data. Regarding grouting pressure, an effectively linear distributed pressure may be considered, accounting for the grout weight and the increase of soil stresses with depth. This validated numerical framework provides valuable guidance for researchers and practitioners to construct more efficient, reliable, and accurate 3-D models. [ABSTRACT FROM AUTHOR]