Effects of construction delays on construction project objectives

Delays can be defined as the late completion of works as compared to the planned schedule on the contract. Delays can be avoided or minimized only when their causes are identified. When delay occurred in to our project, it will have adverse consequences on project objectives in terms of time, cost and quality. The aim of the study reported in this paper was to identify the effects of delays that could threat project objectives in construction projects. A comprehensive literature review from various sources through books, conference proceedings, the internet, and civil engineering journals was made to carry out the study. According to delay categories that were contractor related, client related, consultant related, labor related and external related, the results of this study identified the six major effects of delay that were time overrun, cost overrun, dispute, arbitration, total abandonment, and litigation. The study also revealed that time and cost overruns were the frequent effects of delay. It is hoped that this study will become the foundation of further research in the area of project delays and mitigation measures

Applications of Dynamic Mode Decomposition and Sparse Reconstruction in the Data-Driven Dynamic Analysis of Physical Systems

Recent advancements in data collection methods and equipment have resulted in a huge increase in the amount of data collected by observing various types of physical phenomena. Regardless of the amount of data collected, it is well known for many physical systems, the so-called information rank of the collected data is much lower than the rank of the data itself. This usually means the data may be represented sparsely in terms of a properly-chosen basis. This realization has led to methods for storing large amounts of data through compression by sacrificing negligible data quality. More importantly, with the advent of compressed sensing techniques, using an appropriate representation basis and sampling technique, it is now possible to sample data far below the Shannon-Nyquist limit thus speeding up data acquisition and also reducing the complexity of data-acquisition hardware. In this research, we explore the application of various modern data analysis techniques such as proper orthogonal decomposition (POD), dynamic mode decomposition (DMD), compressed sensing, and Kalman filter and smoother in the data-driven analysis of dynamic systems with many degrees of freedom. This research has resulted in four novel methods. The first method is developed for denoising and spatial resolution enhancement of 4D-Flow MRI data based on POD and sparse reconstruction. The second method combines DMD and compressed sensing and takes discrete cosine transform (DCT) as the representation basis for dynamic denoising and gappy data reconstruction in 2D. The third method is a fast and parameter-free dynamic denoising method which combines a reduced-order model (ROM), a Kalman filter and smoother, and a DMD-based forward model. The fourth method is developed for reconstructing a 2D incompressible flow field by taking sparse measurements from the Fourier domain. As the reconstruction basis, a custom divergence-free set of basis vectors are derived and implemented

Peran Faktor Lingkungan dan Perilaku terhadap Penularan Demam Berdarah Dengue di Kota Mataram

Dengue Hemorrhagic Fever (DHF) is a viral endemic disease in Indonesia transmitted by Aedes mosquitoes vector. The only way to prevent the disease is by cutting disease transmission chain namely vector control that is influenced by environmental and socio-behavioral factors. Therefore the aim of this study was to analyze environmental and socio-behavioral factors influencing DHF epidemic outbreak in Mataram. This study was designed as a cross-sectional observational survey conducted during DHF outbreak in Mataram, Nusa Tenggara Barat province in March to June 2004. Four villages as outbreak zone were taken as study area. Whereas sixteen villages of non-DHF outbreak zone were taken as control area. From each village, ten households were taken as samples amounting to a total sample of 200 people. Associations between environmental factors or socio-behavioral factors with DHF epidemic outbreak were tested by the Chi-square. A both environmental and socio-behavioral factor all together in relation to DHF epidemic outbreak was analyzed using by multiple logistic regression model. The data showed that there were associations between container indexes, attitude to DHF disease, action in vector control, abatization with DHF epidemic outbreak in Mataram in 2004 (Chi- square tests, all p < 0.05). However, in multiple logistic regression model it was revealed that the only container indexes was of significant influence on the DHF epidemic outbreak (p < 0.01) with relative risk (RR) was 2.96. It is concluded that the most important factor influences DHF epidemic outbreak in Mataram is high container index. It is recommended to Local Health Department to increase alertness in pertaining to DHF outbreak by intensifying program of abatization, health education on DHF and action in vector control. There is an urgency of inter-program and inter-sectoral joint cooperation in prevention of DHF outbreak. Keywords : DHF, environmental factor, socio-behavioral facto

Developing Mitigation Measures for Delays in Building Construction Projects: A Case Study in the City of Esfahan

Developing mitigation measures are to avoid or minimize the magnitude of adverse consequences of delay causes that could threat the project objectives in terms of time, cost and quality. It is also vital to be aware of mitigation measures within the construction industry. The aim of the study reported in this paper is to develop mitigation measures for delays in building construction projects in the city of Isfahan, Iran. A questionnaire survey was used to carry out the study which was filled out by professional parties such as clients, contractors, architects, project managers, consultants and developers in the construction industry. Feedbacks from respondents gave variety of measures for each cause of delay to mitigate the adverse and disruptive consequences of delay causes in building construction projects in Isfahan. Time and cost overrun were the common negative effects of delays in building construction projects in Isfahan. The study has found that twenty one significant mitigation measures based on the different points of view from respondents of the questionnaire survey, in order to avoid or minimize the causes of delays in building construction projects in Isfahan, it has been proposed that the top six most effective mitigation measures of avoiding or minimizing these delays were further elaborated. This include: considering the clients views while providing designs, setting the project budget according to proper and accurate estimations, efficient and effective project management among the parties in the project, proper selection of competent and capable contractors appropriate for the project, appropriate delegating of project parties regarding to their specialties and skills and also having sufficient knowledge of project environment and project parties before the project starts. It is hope that this finding will be able to address issues and problems of delays in building construction projects in general in Iran

2D Molecular Dynamics Simulation of Solitons Interaction in Dusty Plasma

Molecular Dynamics (MD) method is used to simulate a dusty plasma system as a one component plasma (OCP).&nbsp; The heavy dust particles are considered as discrete particles interacting with each other through the Yukawa potential. This assumption is justified by the screening effect due to the lighter plasma components (electrons and ions). Solitons excitation at different values of the Coulomb coupling parameter (Γ) is simulated. The formation of solitons in the system using electric field pulse in a narrow region is studied. Different scenarios of the interaction of solitons are studied for: A) Two solitons with the same amplitude and opposite directions.&nbsp; B) Two solitons with different amplitudes and opposite directions.&nbsp; C) Two solitons with different amplitudes and propagating in the same direction

Oral verapamil in paroxysmal supraventricular tachycardia recurrence control: A randomized clinical trial

Background: Adenosine is the first-line medication in patients with paroxysmal supraventricular tachycardia. Because it is cleared so rapidly from the circulation, recurrence of paroxysmal supraventricular tachycardia after initial successful conversion may occur. This study was conducted to evaluate the role of oral verapamil administration to control early recurrences of paroxysmal supraventricular tachycardia after adenosine infusion. Methods: Patients with acute paroxysmal supraventricular tachycardia and no contraindications for adenosine or verapamil treatment were included in study. All patients received an adenosine protocol (6 mg rapid bolus intravenous injection followed by two repeated doses of 12 mg if necessary). Patients in the adenosine-only group did not received any other medications but patients in the adenosine/verapamil group received 40 mg verapamil orally immediately after converting the rhythm to sinus rhythm. All patients were followed up for 6 h in the acute care area of the emergency department under continuous cardiac monitoring. Results: A total of 113 patients were assessed for eligibility and 92 patients were randomized into two groups (adenosine only versus adenosine/verapamil). There was no statistically significant difference in paroxysmal supraventricular tachycardia recurrence rate between the two groups in the first 30 min after treatment. Recurrence rate was statistically significantly lower in the adenosine/verapamil group than in the adenosine-only group between 30 and 120 min after treatment and thereafter. Two patients in the adenosine-only group experienced flushing and one patient in the adenosine/verapamil group experienced decreased systolic blood pressure. Oral verapamil can decrease paroxysmal supraventricular tachycardia recurrence after successful control with intravenous adenosine. © 2014, SAGE Publications. All rights reserved

An Optimum Design of Cam Mechanisms with Roller Follower for Combined Effect of Impact and High Contact Loads

The problem in the design of a cam is the analyzing of the mechanisms and dynamic forces that effect on the family of parametric polynomials for describing the motion curve. In present method, two ways have been taken for optimization of the cam size, first the high dynamic loading (such that impact and elastic stress waves propagation) from marine machine tool which translate by the roller follower to the cam surface and varies with time causes large contact loads and second it must include the factors of kinematics features including the acceleration, velocity, boundary condition and the unsymmetrical curvature of the cam profile for the motion curve.<br /> In the theoretical solution the unidirectional impact stress waves with the Mushkelishvilis inverse of the singular integral equation for contact stress have been used for analytical solution and a numerical solution have bean solved using F.E.M (ANSYS 10) for stress analysis in a cam surface at condition of rise-dwell-return (R-D-R) motion of the follower, also to compare the analytical and numerical results that have been used different pressure angles in the rise and return of the motion curves in unsymmetrical cam profile for optimum design. <br /> <br /

The effect of Melatonin on histological changes of ovary in induced polycystic ovary syndrome model in mice

Antioxidants can be used as adjuvant treatment of polycystic ovary syndrome (PCOS). Melatonin (MT) is one of the antioxidant that is used nowadays. Objective: In this study, the effect of MT on the histological changes of ovary in the experimental model of polycystic ovary syndrome is investigated. Methods: In this study 30 immature female NMRI mice were divided into 5 groups including: (1) control group received distilled water, (2) received a dose of 10. mg/kg MT for 5. days, (3) received Dehydroepiandrostenedione (DHEA) at a dose of 6. mg/kg for 20. days to induce PCOS, (4) after induction of PCOS received MT at a dose of 10. mg/kg for 5. days, and (5) received 6. mg/kg DHEA and 10. mg/kg MT for 20. days simultaneously. Results: The evaluation of ovarian tissue characteristics such as the granulosa layer, theca, number and diameter of cysts and follicles was performed. PCOS caused a significant reduction in the number of antral follicles and corpus luteum and an increase in the number of primordial, primary, pre-antral and cystic follicles in comparison with the control group (P. <. 0.05). Moreover, MT resulted in a significant increase in the granulosa layer thickness in group 4 (P. <. 0.001), and group 5 (P = 0.001) and a significant reduction in the thickness of theca layer between groups 4 and 5 compared with group 3 (P. <. 0.001). Conclusion: These findings indicate that MT have a protective effects on polycystic ovary damages induced by DHEA, although the mechanism is unclear. It is likely that this is happening by reducing oxidative damage. © 2017