Asphalt Works Subcontracting Disputes in Large Construction Programs

Subcontracting is a common, and sometimes warranted, practice on large construction projects. However, it is also well recognized that disputes are likely to develop between subcontractors and general contractors in trying to achieve target objectives of cost, quality, and time. This paper tackles quality- and time-related disputes that are peculiar to the case of subcontracting asphalt works under a large construction program, such as that of a new airport construction. In particular, it reports on disagreements regarding the achieved thickness and surface smoothness of the constructed asphalt concrete layer, and on activity-interfacing and delay-attribution issues resulting from improper contractual and scheduling practices. Factors believed to be relevant to both classes of disputes are identified, and analyses are offered to pinpoint significant anomalies. Finally, arguments are developed and recommendations given, that reflect best industry practices whose application could help minimize the likelihood of facing such disputes in the future.     

Contribution of encapsulation on the biodisponibility of retinol

To show the benefits of retinol encapsulation in cosmetic industry, we compared the diffusion of two different retinol preparations through skin:oil-in-water (o/w) emulsions of retinol, also called 'free retinol', and suspension of Cylasphere including retinol, also called 'encapsulated retinol'. Two methods were used: Franz cell elucidated retinol release and storage in a hairless mouse skin according to time for the two types of preparations. The dosage of retinol by high performance liquid chromatography (HPLC) showed that encapsulated retinol was maintained into the skin for a longer time than free retinol. Raman microspectrometry measurements established a spectral image of the skin and determined the localization of retinol. Maps were collected according to time. They detailed the shifts of free and encapsulated retinol in the epidermis of a human biopsy. Spheres were smaller than droplets and they moved two times faster at this level of the skin.     

Studies of compounds that enhance sphingolipid metabolism in human keratinocytes

Several products are known to inhibit the biosynthesis of ceramides and glucosylceramides, but very few stimulate this process. We studied the influence of a hydrolysate of potato proteins (Lipidessence) in vitro on the sphingolipid metabolism of normal human epidermal keratinocytes. By measuring growth with the thymidine uptake assay, it was seen that Lipidessence, added in the culture medium up to an 8% concentration, did not change significantly the proliferation rate of keratinocytes, but beyond this concentration a progressive dose-dependent inhibition of growth was noticeable. Following incubation of cells with the product at 5% and 10% concentrations for 2 days, the lipids were extracted. The different lipid classes were separated by fractionation on columns of aminopropyl silica gel and analyzed by high-performance thin-layer chromatography. When keratinocytes were cultivated in the presence of Lipidessence, the biosynthesis of cholesterol, phosphatidylcholine, phosphatidylserine and gangliosides was stimulated, and a major increase was noticeable in the biosynthesis of free fatty acids, free ceramides, glucosylceramide and sphingomyelin. Radioactive [(14)C]-serine was used as a precursor of sphingoid bases to study sphingolipid biosynthesis. After migration of lipid fractions on thin-layer plates, autoradiography showed that free ceramides and glucosylceramide were labeled, thus suggesting that de novo biosynthesis was accounting for the increased cellular content in sphingolipids.     

Evaluation of different chemical methods for cros-linking collagen gel, films and sponges

Collagen-based films and sponges are widely used as biomaterials. The rate of their biodegradation can be reduced by treating them with different cross-linking agents. The efficiency of different reticulation procedures on thermal stability (measured by differential scanning calorimetry) and susceptibility to bacterial collagenase digestion of the final material (films or sponges) is compared. The chemical agents used on collagen gels or directly on collagen sponges and films were glutaraldehyde (GTA), hexamethylene diisocyanate (HMDC), cyanamide, 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and the two acyl azide methods (with hydrazine or diphenylphosphorylazide (DPPA)) developed in the authors' laboratory. Under these experimental conditions, collagen stabilization by the different agents increased in the following order: cyanamide T _d=75.8°C; after 3 months, T _d=75.6°C). Direct treatment of collagen films with DPPA gave similar thermal stability (T _d=72.6°C) and collagenase resistance when compared with treatment with 0.6% GTA for 96 h (T _d=74.6°C). It is demonstrated that collagen sponges and films can be prepared with a wide range of thermal stability (49–75.8°C) and collagenase digestion resistance (10–100%). Recent biocompatibility studies show, however, that DPPA and EDC are the best choices for preparing cross-linked collagen sponges and films.     

The perceptual experience of slope by foot and by finger.

Historically, the bodily senses have often been regarded as impeccable sources of spatial information and as being the teacher of vision. Here, the authors report that the haptic perception of slope by means of the foot is greatly exaggerated. The exaggeration is present in verbal as well as proprioceptive judgments. It is shown that this misperception of pedal slope is not caused by calibration to the well-established visual misperception of slope because it is present in congenitally blind individuals as well. The pedal misperception of slope is contrasted with the perception of slope by dynamic touch with a finger in a force-feedback device. Although slopes feel slightly exaggerated even when explored by finger, they tend to show much less exaggeration than when equivalent slopes are stood on. The results are discussed in terms of a theory of coding efficiency. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Process Model for Administrating Construction Claims

Claims for additional costs and time extensions result from a variety of events occurring during the course of construction. To enhance the chances of success, contractors submitting claims must closely follow the steps stipulated in the contract conditions, provide a breakdown of alleged additional costs and time, and present sufficient documentation. On the other hand, project owners need to follow an overall comprehensive step-by-step procedure for tracking and managing the claims submitted by contractors. The paper presents a claims-management process that could be used by all parties involved in construction. The process identifies the major information-gathering and decision-making milestones as well as the notice and substantiation compliance checkpoints, which are critical to the development of defense arguments as claims are addressed. It further emphasizes the use of tools such as simulation, scheduling, productivity, and economic analysis and other modeling techniques in judging the level of justification and reasonableness of submitted claims.     

Career Planning and Progression for Engineering Management Graduates: An Exploratory Study

Abstract:

When faced with the decision of selecting an advanced degree, many engineers opt for management related studies rather than further specialization in a technical field. This article attempts to highlight the reasons behind such choices, and explores the role that a Master's degree in Engineering Management (MEM) plays in career planning and progression. A survey of 58 MEM graduates, who completed their studies at a prominent university in Lebanon between 1992 and 2009, reveals that the majority of the respondents follow a linear career path, rapidly paving the way towards managerial positions. For most of the respondents, earning a graduate degree in engineering management played a primary role in, or at least contributed to, making this shift. The article concludes with a diagram sketching the possible career paths for MEM graduates. By showing the number of years spent at different career stages, the diagram serves as a career-planning tool for MEM graduates, engineers, managers, and researchers.     

Knowledge Management in Mechanical and Industrial Engineering Consulting: A Case Study

The goal of knowledge management as a process is to improve the organization’s ability to execute its core business functions more efficiently and effectively. The key to knowledge management is capturing intellectual assets for the tangible benefit of the organization. On the other hand, the aim of any design engineering consulting firm is to produce projects with high quality and in less time. The paper starts by discussing the importance of knowledge management in improving the competitive edge of firms in general and of consulting firms in particular. Then, the paper discusses the process of building a knowledge management system in the Mechanical and Industrial Department at DAR AL HANDASAH, which is a leading consulting firm in the Middle East and the world. The paper concludes with the lessons learned from the experience of building the knowledge management system and the steps needed to improve it.