Project Change Management System

Changes in projects are common and may be deleterious or beneficial—whether you see a change as a conflict or a valuable lesson depends only on your prospective. Project changes affect the cost, the scheduling, and the duration of projects, both directly and indirectly. Despite many articles and much discussion in practice and academic literature, there is a lack of information about systematic approaches to manage project change. This paper introduces a comprehensive project change management system that is founded on five principles: (1) promote a balanced change culture; (2) recognize change; (3) evaluate change; (4) implement change; and (5) continuously improve from lessons learned. By applying this project change management system, project participants can minimize deleterious change and promote beneficial change.     

Preparation of hexagonal potassium tungsten bronze thin films by thermal vacuum evaporation

$\text{K}{}_{\mathrm{x}}\text{WO}{}_{\mathrm{<mtext>3+</mtext><mtext>x</mtext><mtext>2</mtext>}}\text{(}\text{x}\text{= 0.3)}$ thin films have been prepared by the thermal vacuum evaporation technique. Depending on the substrate temperature during deposition, either amorphous or crystalline films could be obtained. X-ray diffraction patterns and pole-figure information revealed that fresh crystalline films deposited on a hot (about 400°C) substrate of indium-tin oxide on glass microscope slides had a preferred orientation, with the c-axis perpendicular to the surface of the film. SIMS depth profiles and RBS experiments were used to confirm the stoichiometry and uniformity of the chemical components in the thermally deposited films.     

Measurement of the heat transfer coefficient in the dimpled channel: effects of dimple arrangement and channel height

Heat transfer coefficients were measured in a channel with one side dimpled surface. The sphere type dimples were fabricated, and the diameter (D) and the depth of dimple was 16 mm and 4 mm, respectively. Two channel heights of about 0.6D and 1.2D, two dimple configurations were tested. The Reynolds number based on the channel hydraulic diameter was varied from 30000 to 50000. The improved hue detection based transient liquid crystal technique was used in the heat transfer measurement. Heat transfer measurement results showed that high heat transfer was induced downstream of the dimples due to flow reattachment. Due to the flow recirculation on the upstream side in the dimple, the heat transfer coefficient was very low. As the Reynolds increased, the overall heat transfer coefficients also increased. With the same dimple arrangement, the heat transfer coefficients and the thermal performance factors were higher for the lower channel height. As the distance between the dimples became smaller, the overall heat transfer coefficient and the thermal performance factors increased. This paper was recommended for publication in revised form by Associate Editor Yong Tae Kang Jae Su Kwak received his B.S. and M.S. degrees in Mechanical Engineering from Korea University in 1996 and 1998, respectively. He then received his Ph.D. from Texas A&M University in 2002. Dr. Kwak is currently an Assistant Professor at the School of Aerospace and Mechanical Engineering at Korea Aerospace University in Goyang-City, Korea. His main research interests include gas turbine heat transfer, compact heat exchanger, and enhancement of heat transfer.     

Induction motor parameter tuning for high-performance drives

A new approach to the parameter tuning of induction motors in the course of drive commissioning is proposed. Usually, the motors originate from different manufacturers, and so the parameters are not known prior to startup of the drive. The control system of the drive utilizes the parameters obtained by extraneous tests and based on a number of assumptions that are not valid under all operating conditions. Therefore, completion of the tuning of all motors at an industrial site is quite time consuming, and it is a very difficult job, even to skilled engineers. To overcome these problems, the proposed tuning procedure is sensitive to detuning and independent of information on other parameters. The state of detuning is clearly noticeable in the shape of the controller output signal of the drive system. The proposed scheme has the advantage of being general and readily applicable to a wide range of other systems, such as AC/DC boost converters, surface-mounted permanent-magnet synchronous motors, interior permanent-magnet synchronous motors, etc. Experimental results are offered to validate the feasibility of the proposed tuning algorithm     

Exposure assessment of engineered nanomaterials in the workplace

Nanotechnology is a rapidly growing field and numerous products containing engineered nanomaterials are already in the market. With the increasing use of engineered nanomaterials, it is expected to increase the exposures to nanomaterials in the workplace. However, the researches on the exposure assessment of nanomaterials to humans and the environment are just a beginning step, as the nanotechnology industries are expanding. Questionnaire surveys conducted by various organizations reveal that many nanotechnology companies are searching for information on exposure measurement for the protection of workers who handle nanomaterials. We analyze the trends of researches on the occupational exposure measurement of engineered nanomaterials and investigate the methodologies of exposure assessment recommended by the related working groups. This work is expected to fill the gaps in knowledge on the exposure assessment of nanomaterials.     

Frequency response of continuous-flow adsorber for multicomponent system

In this paper, we present a theoretical analysis of the frequency response of a continuous-flow adsorber with periodic modulation of the inlet flow-rate to measure multicomponent diffusion kinetics in porous media. Micropore diffusion kinetics is assumed for the intraparticle mass transfer mechanism and three different shapes of microparticle are considered: slab, cylinder, and sphere. Simulation results for a binary system show that the frequency response of the faster diffusing component is strongly influenced by the slower component. The out-of-phase characteristic function of the frequency response of the faster diffusing component shows maximum and minimum points. The deviation between these maximum and minimum values becomes smaller when the cross-terms of diffusivity go to zero, while the deviation becomes larger when the cross-terms of the adsorption equilibrium constant go to zero. Contrary to the behaviour of the out-of-phase function of the faster diffusing component, the out-of-phase function of the slower diffusing component shows no extrema at all. The in-phase characteristic function of the frequency response of the continuous-flow adsorber is not affected by the overflow parameter.     

Optimal design of composite hood with reinforcing ribs through stiffness analysis

Fiber glass reinforced composites like sheet molding compounds (SMC) have recently been widely used in the fabrication of two-piece automobile hoods for passenger cars. In the present investigation, a one-piece composite hood with reinforcing ribs was optimally designed and manufactured by resin transfer molding in order to reduce manufacturing cost. In order to obtain the optimal design, stiffness analyses for deflections due to self-weight, oil canning, and torsion test conditions were carried out by applying the ABAQUS/Standard program. Based on these analyses, the thickness dimension of the composite hood required to maintain a stiffness comparable to a conventional steel hood was determined. For optimization studies of the weight reduction of the currently proposed one-piece composite hood with reinforcing ribs, IDESIGN program was employed. Based on a recursive quadratic programming technique, the thickness dimensions of the reinforcing ribs were optimized. The deflection ratios between fiber glass reinforced composite and conventional steel hoods were minimized in the optimization studies. From the present studies, it was found that the weight saving effect obtained by introducing the optimally designed one-piece composite hood was 37% compared to the conventional steel hood. This ranged approximately from 30 to 40% for composite hoods manufactured by resin transfer molding, depending on the composite materials used. Through these studies, it was confirmed that the one-piece composite hood was a preferable design and manufacture, compared to currently used composite hood made in two pieces, in terms of weight reductions and manufacturing cost without losing the stiffness required.     

Analyzing Enterprise Resource Planning System Implementation Success Factors in the Engineering–Construction Industry

Enterprise resource planning (ERP) systems offer many benefits to the engineering–construction industry. Many construction firms recognize the benefits of ERP system implementation; however, they still hesitate to adopt these systems due to high cost, uncertainties, and risks. This study identifies and analyzes critical factors that need to be considered to ensure successful ERP system implementation in the construction industry. First, this paper identifies the factors associated with the success and failure of ERP systems, and provides indicators to evaluate the success of such systems. Then, the paper develops an information system success model to analyze the relationships between factors and success indicators. Finally, the paper provides recommendations for successful ERP systems based on the analysis. The derived success factors should help senior managers in construction firms make better decisions and improve their business value by implementing the most effective EPR systems.     

Probing the reaction pathway of dehydrogenation of the LiNH2 + LiH mixture using in situ H NMR spectroscopy

Using variable temperature in situ ¹H NMR spectroscopy on a mixture of LiNH₂ + LiH that was mechanically activated using high-energy ball milling, the dehydrogenation of the LiNH₂ + LiH to Li₂NH + H₂ was investigated. The analysis indicates NH₃ release at a temperature as low as 30 °C and rapid reaction between NH₃ and LiH at 150 °C. The transition from NH₃ release to H₂ appearance accompanied by disappearance of NH₃ confirms unambiguously the two-step elementary reaction pathway proposed by other workers.     

Effects of surface treatment using aqua regia solution on the change of surface band bending of p-type GaN

Effects of surface treatment on the change of band bending at the surface of p-type GaN were studied using synchrotron radiation photoemission spectroscopy, and the results were used to interpret the reduction of contact resistivity by the surface treatment. The contact resistivity on p-type GaN decreased from (5.1±1.2)×10⁻¹ to (9.3±3.5)×10⁻⁵Ω cm² by the surface treatment using aqua regia prior to Pt deposition. Surface band bending was reduced by 0.58 eV and 0.87 eV after the surface treatments by HCl and aqua regia solutions, respectively. The atomic ratio of Ga/N decreased as the photoelectron detection angle was decreased, indicating that the surface oxide was mainly composed of Ga and O, GaO_x, formed during high-temperature annealing for the generation of holes, and Ga vacancies, V_Ga, were produced below the GaO_x layer. Consequently, the aqua regia treatment plays a role in removing GaO_x formed on p-type GaN, leading to the shift of the Fermi level toward the energy levels of V_Ga located near the valence band edge. This causes the decrease of barrier height for the transport of holes, resulting in the good ohmic contacts to p-type GaN.