Time-Uncertainty Analysis by Using Simulation in Project Scheduling Networks

Risks are inherently present In all construction projects. Quite often, construction projects fail to achieve their time quality and budget goals. Risk management is a subject, which has grown in popularity during the last decade. It is a formal orderly process for systematically identifying, analysing and responding to risks associated with construction projects so as to reduce the effects of these risks to an acceptable level. Risk analysis is primarily concerned with evaluating uncertainties. The purpose of risk analysis is to enable a decision-maker to take an appropriate response in advance against a possible occurrence of a problem. In this study, Monte Carlo simulation as a tool of risk analysis was used. The merge event bias as one of the essential problems associated with PERT is discussed, along with models and approaches developed by other researchers, namely, Probabilistic Network Evaluation Technique (PNET algorithm), Modified PNET, Back-Forward Uncertainly Estimation procedure (BFUE) and concept based on the robust reliability idea. These developed approaches are more reliable in planning construction projects compared to PERT because they attempt to handle the merge event bias problem. In addition, this study demonstrates a number of benefits. the most significant among them being that: (1) Formal risk management tec1miques are rarely used in construction. Dealing with risk management in construction is now essential for minimizing losses and to enhance profitability. (2) It is very dangerous to rely only on PERT/CPM conventional techniques in scheduling projects. (3) To use floats, as stated by traditional resource allocation method, is not practicable. (4) For a project network, the likelihood completion date of a project is exactly equal to the product of the probabilities of each path, separately, with respect to a project completion date. Using simulation now validates this statement. (5) The\ud computation error of a project likelihood completion date is less than 10 percent if a path of a float greater than twice the larger standard deviation of this mentioned path and the critical path is dropped from the calculation, and (6) An effective risk response framework is introduced to help contractors systematically manage the risk in scheduling their projects

A Study of IT Facilities and E-Business System Adoption in Libyan Manufacturing Companies

It is generally believed that larger manufacturing organizations respond more swiftly to changes in the global market place because they have better resources at their disposal. These companies are therefore able to remain competitive by formulating the appropriate corporate strategies and making investments which enable them to maintain their strategic position. An opinion based on the activities of such organizations might be misleading in validating a country's manufacturing strategy. This research gives an account to Libyan Manufacturing Companies and their adoption of IT facilities and E-business within the Industry. A sample of hundred questionnaires was sent to Libya, only sixty were returned. The results demonstrate that LMCs do not only require the usability of IT facility to enhance their workforce activities; but also some interests into Managerial, leadership, and technical skills as well

The potential use of bio-ultracarbofluids in a standard diesel engine

The replacement of diesel fuel by ultra-carbofluids was perceived to offer the potential to decrease the emissions of environmental pollutants such as carbon dioxide, carbon monoxide, hydrocarbons (HC's) and smoke. Such ultracarbofluids consist of a suspension of coal in fuel oil and water generally in the ratio of 5: 3: 2 plus a small amount of stabilising additive. The literature relating to the economies of coal and fuel oil production, and the production and properties of charcoal and vegetable oils has been critically reviewed. The potential use of charcoal and vegetable oils as replacements for coal and fuel oil are discussed. An experimental investigation was undertaken using novel bio-ultracarbofluid formulations. These differed from an ultracarbofluid by having bio-renewable charcoal and vegetable oil in place of coal and fuel oil. Tests were made with a Lister-Petter 600cc 2-cylinder, 4-stroke diesel engine fitted with a Heenan-Froude DPX 1 water brake dynamometer to measure brake power output, and Mexa-321E and Mexa-211E analysers to measure exhaust pollutants. Measurements were made of engine brake power output, carbon dioxide, carbon monoxide, hydrocarbons and smoke emissions over the speed range 1000 to 3000 rpm at 200 rpm intervals. The results were compared with those obtained with a standard diesel reference fuel. All the bio-ultracarbofluid formulations produced lower brake power outputs (i.e. 5.6% to 20.7% less brake power) but substantially improved exhaust emissions of CO2, CO, HC's and smoke. The major factor in the formulation was found to be the type and amount of charcoal; charcoal with a high volatile content (27.2%) and present at 30% by mass yielded the best results, i.e. only slightly lower brake power output and significantly lower exhaust pollutants

Hepatic artery pseudoaneurysm mimicking Mirizzi syndrome

Acute cholecystitis leading to development of a pseudoaneurysm of the hepatic artery is a very rare complication; however, a pseudoaneurysm resulting in gallbladder neck compression with dilatation of intrahepatic duct giving a Mirizzi syndrome like presentation is virtually unreported to the best of our knowledge. We report a case of a 60 years male patient who presented in emergency department with right hypochondrial pain and mild jaundice. Initial diagnosis of hepatic artery pseudoaneurysm causing compression of neck of gallbladder and common bile duct was made on ultrasound examination. This was resulting in gross distention of gallbladder and mild dilatation of intrahepatic ducts. Findings were confirmed on CT scan. Later successful selective transcatheter arterial embolization of the aneurysm and percutaneous cholecystostomy were performed

Factors affecting career choice among undergraduate students in Universitas Indonesia

One of the critical aspects of an individual’s life is career choice as a career chosen will determine the role pattern need to be played by the individual in the society in the future and the career choice is one of the important processes in life. The aim of this study is to investigate the factors that influencing the career choice of the students. This study is focus on undergraduate students in Universitas Indonesia. Undergraduate students were chosen because right upon graduation, they were the one who will be dealing with the decision on career choice. A total number of 300 students responded to the questionnaire. Statistical Package software for Social Science (SPSS) Version 22.0 was used to analyse the collected data. Reliability analysis, multiple regressions, and correlation were applied to this study. Pearson correlation analysis results showed that the influence of self-efficacy, family, personal interests, and economic considerations have positive relationships to career choices. Moreover, the results of regression analysis showed that the family, self-efficacy, personal interest and economic considerations exerted great influence on the choice of a career. With a view to investigating student’s career choice that is affected by other important factors further studies are recommended strongly

Assessment of Structural Strength of Commercial Sandcrete Blocks in Kano State

This research was aimed at studying the strength properties of the commercial sandcrete blocks produced in Kano State. A total number of 250 block samples were randomly collected from five local government areas, fifty (50) from each of the local governments and cured for 3, 7, 14, 21 and 28 days. The blocks were subjected to various tests at wet and dry conditions as follow: wet compressive test, drying shrinkage, moisture movement and density all in accordance with established standards in the structural laboratory of Department of Civil Engineering, Ahmadu Bello University, Zaria, and the aggregates were subjected to sieve analysis and moisture content determination in the Geotechnical Laboratory of the department. The compressive strength was found to be between 0.25 N/mm2 and 0.92 N/mm2 which are far below the specified values (2.5 N/mm2 to 3.45N/mm2 respectively) in the Nigerian Industrial Standard (NIS 87, 2000). It is concluded that the commercially produced sandcrete blocks in Kano State are of lower standard than expected. It is recommended that workshop should be organised periodically to enlighten the producers of sandcrete blocks. The importance of adhering to standard specifications should be emphasised and strict penalties be meted out to erring producers by the Nigerian Industrial Standard Organisation.Keywords: sandcrete blocks, compressive strength, Kano State, British standard, mix rati

Changing pattern and etiology of maxillofacial fractures during the civil uprising in Western Libya

The purpose of the present study was to evaluate changing pattern in characteristics of maxillofacial fractures and concomitant injuries in Western Libya During revolution and to assess the association between mechanism of injury and fracture patterns. A retrospective review of medical records and radiographs of 187 patients treated for maxillofacial fractures from January 2010 to December 2012 was performed, there were 326 fractures in 187 patients. The male: female ratio was 6:1. Most fractures occurred in patients aged 11 to 40 years, and few injuries occurred in patients aged > 50 years. Most fractures occurred from motor vehicle accidents, and other most frequent causes included assault, gunshot, and fall injuries. Most maxillofacial fractures involved the mandible, zygomatic complex, or maxilla. Most mandibular fractures occurred at the parasymphysis, angle, or condyle. Associated injuries most frequently involved the head, chest, and extremities. Most patients were treated with open reduction (132 patients [71%]), and 26 patients (14%) were treated nonoperatively. There were 21 complications (11%). In summary, motor vehicle accidents were the most frequent cause of maxillofacial fracture in western Libya, possibly because of the lack of seat belt legislation. Interpersonal violence was a less frequent cause of maxillofacial fracture, possibly because of the religious restriction on alcohol consumption

Genetic Variants of Serum Alpha 1 Antitrypsin

Complete absence of data on alpha 1 antitrypsin in this country prompted us to determine serum levels using radial immunodiffusion (RID) and phenotypes by isoelectric focusing (IEF) in 100 healthy adults (52 males and 48 females). Mean serum alpha 1 antitrypsin concentration in healthy subjects was 2.47±0.08 g/l and the main phenotypes MM (70%), M1 M2 (28%) and FM 3(2%) are infrequent in our population (JPMA 45:245,1995)

Wandering spleen: Case report and literature review

The spleen is fixed in the left upper abdominal quadrant by various ligaments. Any ligament laxity or defect will result in a rare condition called “wandering spleen.” <500 cases have been reported in the literature. This study presents the case of 22-year-old female who was presented with nonspecific chronic abdominal pain and distention although; she had normal abdominal examination and laboratory investigations. A computed tomography scan showed a homogenous pelvic mass, suggesting a wandering spleen; therefore, a laparoscopic splenectomy was performed. The objective of this study was to report and review a rare condition that requires a high index of suspicion to make a correct diagnosis