Electrochemical and photoelectrochemical behaviour of passivated niobium electrodes during hydrogen evolution

The electrochemical and photoelectrochemical behavior of niobium electrodes passivated in 0.5 M H₂SO₄ and 1 M HNO₃ has been investigated. High intensity pulse lasers were used as light sources. This technique allows photoelectrochemical measurements with light wavelengths smaller than the band gap of the semiconducting passive film. The donor concentration and the flat band potential of the passive films were calculated from capacity measurements. The effect of cathodic hydrogen evolution on the behaviour of the oxide film formed was found to depend on the time of the cathodic treatment of the electrode. The results showed that the behaviour of the passive film formed on niobium in nitric acid is different from that formed in sulphuric acid. The calculated donor concentrations and the extrapolated flat band potentials indicate that the nature of the passive film depends on the formation medium. The adsorption of hydrogen on the passivated Nb-electrode up to a time limit of 1 ms could be traced using photocharge measurements with excitation energies less than the band gap energy of the semiconducing oxide film.     

Trade and the environment: identifying "hot spot" sectors

A prioritization methodology was developed to identify key "hot spot" sectors that are vulnerable to adverse environmental impacts from trade liberalization. The methodology relies on internationally approved analytical techniques and indicators relevant to the trade and environment issue. Key outputs of this research include the identification of appropriate economic and environmental indicators, an information compilation strategy, and a step-wise procedure to perform the prioritization process. The methodology presented may reduce time and expenses previously incurred in identifying environmental hot spots. It also may assist in prioritizing actions to mitigate negative consequences of trade liberalization in specific sectors. Electronic Publication     

Frost formation and heat transfer on a cold surface in ice fog

In this paper a semi-empirical model describing heat and mass transfer on a cold surface in humid air under supersaturated frosting conditions is presented. The lack of psychrometric data in the supersaturated zone of the psychrometric chart has historically impeded the ability of researchers to accurately predict heat and mass transfer in supersaturated air. The work described in this paper has been partially made possible by developing a systematic procedure to compute the properties of supersaturated air, especially in the low temperature zone of the psychrometric chart. Development of such a capability will allow us to predict the amount of frost collected, the frost deposition and heat transfer rates, frost thickness and surface temperature, and other important parameters.     

An apparatus for the study of wear under dynamic loading conditions

A multipurpose wear testing apparatus has been designed, constructed and calibrated. The apparatus is primarily an impact wear testing device, but it may also be used for vibratory and oscillatory wear experimentation. The system utilizes a versatile displacement- and force-controlled device, which allows accurate control and measurement of the load cycles and their frequencies and the relative normal and transverse velocities between the wear surfaces as well as their time of contact. Features of this design permit testing at elevated frequencies and investigation of the effect of individual parameters on the wear process. These features include a facility to manipulate the system stiffness, the ability to control the impact and rotational velocities independently, feedback to maintain a constant nominal stress parameter, the ability to use spherical or cylindrical wear specimens and a method of applying the load and relative transverse motion in a constant, random or prescribed manner. The design facilitates modifications to include lubrication and environmental control, measurement of friction forces and fretting wear capabilities. Some initial results are included.     

Adaptive allocation of resources and call admission control forwireless ATM using genetic algorithms

In wireless ATM-based networks, admission control is required to reserve resources in advance for calls requiring guaranteed services. In the case of a multimedia call, each of its substreams (i.e., video, audio, and data) has its own distinct quality of service (QoS) requirements (e.g., cell loss rate, delay, jitter, etc.). The network attempts to deliver the required QoS by allocating an appropriate amount of resources (e.g., bandwidth, buffers). The negotiated QoS requirements constitute a certain QoS level that remains fixed during the call (static allocation approach). Accordingly, the corresponding allocated resources also remain unchanged. We present and analyze an adaptive allocation of resources algorithm based on genetic algorithms. In contrast to the static approach, each substream declares a preset range of acceptable QoS levels (e.g., high, medium, low) instead of just a single one. As the availability of resources in the wireless network varies, the algorithm selects the best possible QoS level that each substream can obtain. In case of congestion, the algorithm attempts to free up some resources by degrading the QoS levels of the existing calls to lesser ones. This is done, however, under the constraint of achieving maximum utilization of the resources while simultaneously distributing them fairly among the calls. The degradation is limited to a minimum value predefined in a user-defined profile (UDP). Genetic algorithms have been used to solve the optimization problem. From the user perspective, the perception of the QoS degradation is very graceful and happens only during overload periods. The network services, on the other hand, are greatly enhanced due to the fact that the call blocking probability is significantly decreased. Simulation results demonstrate that the proposed algorithm performs well in terms of increasing the number of admitted calls while utilizing the available bandwidth fairly and effectively     

Critical pathways to enhanced innovation diffusion and business performance in Australian design firms

This paper presents a study that extends on previous empirical research, which examined the role of enabling ‘climate for innovation’ constructs in determining the level of innovation diffusion outcomes, and subsequent business performance in architectural and engineering design (AED) firms. Whilst this previous study elucidated the relationships between broad theoretical constructs, the present study was focused on targeting the significant enabling factor interrelationships with the core outcomes that result from the innovation diffusion process. To achieve this objective, a sequential mixed-method research design combining quantitative and qualitative analysis techniques was employed. The quantitative techniques included a correlation analysis to identify the strong factor relationships, followed by Structural Equation Modelling (SEM) to determine the critical pathways for enhancing innovation diffusion and ultimately heightened levels of client satisfaction. Following path model extraction, qualitative interviews with five Australian AED firms were conducted. The interview findings confirmed the uncovered significant pathways, and provided in-depth insights into how the improvement of critical enabling factors could leverage improved innovation diffusion outcomes and business performance.     

The search for quality: The case of planned obsolescence

Planned obsolescence involves a design plan that is intended to hasten existing products to become undesirable (not necessarily below that of competitive offerings) either functionally or psychologically and consequently to be replaced by new products. Many manufacturing companies since the last decade have adopted the policy of planned obsolescence in their products. Their main objective is to cut costs, increase profits and secure continuous consumption and production. When this policy is abused, however, so that customers are not getting products which can perform adequately and safely for a reasonable amount of time, the end result may prove to be more detrimental than beneficial, not only to producers and consumers but to the nation as a whole. In this age of scarce resources, energy shortages and new challenges, this paper re-examines planned obsolescence and searches for quality in todays products.     

Improving software quality through formal inspections

Software safety is a relatively new concept in the software reliability and quality assurance disciplines. Several techniques for conducting software safety analysis are available, and include the following: Peer Circuit Analysis, Software Fault Trees, Nuclear Safety Cross-Check and Petri Nets. This paper puts forward Technical Walkthroughs as an effective method of the Peer Circuit Analysis technique. The paper emphasizes the characteristics of efficient technical walkthroughs that improve the safety and quality assurance function of software in each phase of its life cycle development process. The paper identifies walkthroughs objectives, responsibilities, participants, rules agendas and feedback protocols.     

Photocatalytic oxidation of ciprofloxacin under simulated sunlight

Ciprofloxacin (CIP) is a famous synthetic chemotherapeutic antibiotic. It is widely found either in water or wastewater. In this study ciprofloxacin was photocatalytically degraded using commercial anatase titanium dioxide (TiO(2)) under simulated sunlight. The rate of reaction was found to be affected by pH, TiO(2) concentration and antibiotic concentration. The best reaction rate was obtained in natural ciprofloxacin pH (5.8) and 1000 mg/L TiO(2). More titania concentration was found to reduce the reaction rate because of the limitation in light transmittance. From kinetic studies, the reaction was proved to proceed through adsorption step then photooxidation and obeys pseudo-first order kinetics.