Sintering and densification mechanisms of Y2BaCuO5 pellets

The sintering and densification of Y2BaCuO5 (Y-211) pellets made from powders with different characteristics have been investigated in the temperature range 1000-1140°C. A pellet made from powder containing Ba-rich secondary phases shows very early liquid-assisted sintering and densification and clear evidence of exaggerated grain growth. The melting of BaCuO2 and YBa2Cu3O7-δ (Y-123) secondary phases increases the rate of densification of Y-211 pellets made from other powders at temperatures above 1025-1030°C. All the liquid produced by the melting of the latter phases recrystallizes as intergranular layers of Y-123. These intergranular layers account for the darker appearance and for measurable electrical conductivities at room temperature of the pellets sintered at the higher temperatures. The development of exaggerated grain growth within a uniform fine-grained matrix opens the possibility of using controlled secondary recrystallization to obtain large single domains of Y-211, provided that the trapping of porosity can be avoided or minimized. © 1999 Elsevier Science S.A.

A social matching system : using implicit and explicit information for personalized recommendation in online dating service

Online dating websites enable a specific form of social networking and their efficiency can be increased by supporting proactive recommendations based on participants' preferences with the use of data mining. This research develops two-way recommendation methods for people-to-people recommendation for large online social networks such as online dating networks. This research discovers the characteristics of the online dating networks and utilises these characteristics in developing efficient people-to-people recommendation methods. Methods developed support improved recommendation accuracy, can handle data sparsity that often comes with large data sets and are scalable for handling online networks with a large number of users.

Characteristics of chemotherapy practice in rural and remote area health facilities in Queensland

Objective The overall objective of this study was to document the nature of the chemotherapy nursing practice of rural and remote area nurses in Queensland. Design A questionnaire survey that elicited descriptive quantitative and qualitative data. Setting Forty-seven rural and remote area health facilities in Queensland involved in the administration of chemotherapy. Subjects Sixty-seven Queensland rural and remote area nurses involved in the administration of cytotoxic drugs. Main outcome measures: Characteristics of chemotherapy practice including context of practice, amount and type of chemotherapy administered, logistical problems, level of support from referral centres, policies and procedures, safety issues. Results The results indicate that the risks to nursing staff and the potential for poor patient outcomes are higher than in specialist chemotherapy facilities. This is largely due to the human and material resource constraints characteristic of rural practice. These include a lack of understanding on the part of metropolitan-based health departments and the specialist cancer centres that refer patients to rural areas of the constraints that may adversely influence patient outcomes. Conclusions It is essential that steps are taken to ensure that rural and remote area cancer patients have equitable access to safe and competent chemotherapy care delivered in their choice of context, and the results of this study provide guidance on ways that this can be achieved.

Characteristics of on-road driving performance of persons with central vision loss who use bioptic telescopes

Purpose. To compare the on-road driving performance of visually impaired drivers using bioptic telescopes with age-matched controls. Methods. Participants included 23 persons (mean age = 33 ± 12 years) with visual acuity of 20/63 to 20/200 who were legally licensed to drive through a state bioptic driving program, and 23 visually normal age-matched controls (mean age = 33 ± 12 years). On-road driving was assessed in an instrumented dual-brake vehicle along 14.6 miles of city, suburban, and controlled-access highways. Two backseat evaluators independently rated driving performance using a standardized scoring system. Vehicle control was assessed through vehicle instrumentation and video recordings used to evaluate head movements, lane-keeping, pedestrian detection, and frequency of bioptic telescope use. Results. Ninety-six percent (22/23) of bioptic drivers and 100% (23/23) of controls were rated as safe to drive by the evaluators. There were no group differences for pedestrian detection, or ratings for scanning, speed, gap judgments, braking, indicator use, or obeying signs/signals. Bioptic drivers received worse ratings than controls for lane position and steering steadiness and had lower rates of correct sign and traffic signal recognition. Bioptic drivers made significantly more right head movements, drove more often over the right-hand lane marking, and exhibited more sudden braking than controls. Conclusions. Drivers with central vision loss who are licensed to drive through a bioptic driving program can display proficient on-road driving skills. This raises questions regarding the validity of denying such drivers a license without the opportunity to train with a bioptic telescope and undergo on-road evaluation.

Visibility-related characteristics of crashes involving bicyclists and motor vehicles – Responses from an online questionnaire study

Bicyclists are among the most vulnerable of road users, with high fatal crash rates. Although visibility aids have been widely advocated to help prevent bicycle-vehicle conflicts, to date no study has investigated, among crash-involved cyclists, the kind of visibility aids they were using at the time of the crash. This study undertook a detailed investigation of visibility factors involved in bicyclist-motor-vehicle crashes. We surveyed 184 bicyclists (predominantly from Australia via internet cycling forums) who had been involved in motor vehicle collisions regarding the perceived cause of the collision, ambient weather and general visibility, as well as the clothing and bicycle lights used by the bicyclist. Over a third of the crashes occurred in low light levels (dawn, dusk or night-time), which is disproportionate given that only a small proportion of bicyclists typically ride at these times. Importantly, 19% of these bicyclists reported not using bicycle lights at the time of the crash, and only 34% were wearing reflective clothing. Only two participants (of 184) nominated bicyclist visibility as the cause of the crash: 61% attributed the crash to driver inattention. These findings demonstrate that crash-involved bicyclists tend to under-rate and under-utilise visibility aids as a means of improving their safety.

On the periodicity of traffic oscillations and capacity drop : the role of driver characteristics

This paper shows that traffic hysteresis, a manifestation of driver characteristics, has a profound impact on the development of traffic oscillations and the bottleneck discharge rate. Findings suggest that aggressive driver behavior (with small response times and jammed spacing) leads to spontaneous formations of stop-and-go disturbances. Furthermore, the aggressive behavior, coupled with a late response to adopt less aggressive behavior, generates large hysteresis that leads to oscillations’ transformation from localized to substantial disturbances and growth. The larger the magnitude of hysteresis is, the larger the growth is. Our finding also suggests that the bottleneck discharge rate can diminish by 8-23% when driver adopts a less aggressive reaction to a disturbance (characterized by a larger response time). This finding is particularly notable since lane-changes have been believed to be the major cause of a reduction in bottleneck discharge rate.

Double strap joint tests to determine the bond characteristics between CFRP and steel plates

Advanced composite materials offer remarkable potential in the upgrade of civil engineering structures. The evolution of CFRP (carbon fibre reinforced polymer) technologies and their versatility for applications in civil constructions require comprehensive and reliable codes of practice. Guidelines are available on the rehabilitation and retrofit of concrete structures with advanced composite materials. However, there is a need to develop appropriate design guidelines for CFRP strengthened steel structures. It is important to understand the bond characteristics between CFRP and steel plates. This paper describes a series of double strap shear tests loaded in tension to investigate the bond between CFRP sheets and steel plates. Both normal modulus (240 GPa) and high modulus (640 GPa) CFRPs were used in the test program. Strain gauges were mounted to capture the strain distribution along the CFRP length. Different failure modes were observed for joints with normal modulus CFRP and those with high modulus CFRP. The strain distribution along the CFRP length is similar for the two cases. A shorter effective bond length was obtained for joints with high modulus CFRP whereas larger ultimate load carrying capacity can be achieved for joints with normal modulus CFRP when the bond length is long enough.

How international entrepreneurship characteristics influence Internet capabilities for the international business processes of the firm

This research explores the relationship between international entrepreneurship characteristics and the use of Internet capabilities for the international business processes of the firm. It has been suggested, that the accumulation of a firms Internet capability can assist international operations, especially when operating in fast changing dynamic Internet environments. However, international entrepreneurship characteristics which are seen as a precursor to leveraging Internet capabilities are still vague. Given this finding, eight case studies of small and medium sized travel and tourism firms were selected to investigate the influence of international entrepreneurship characteristics, and Internet capabilities for international business processes. Based on the eight in-depth case studies, the results signify that successful international entrepreneurial firms which encompass high levels of international innovativeness and proactiveness behaviour integrate Internet capabilities to a greater degree. Our findings also indicate that the prior international business experience, international risk-taking propensity and international networking characteristics are not necessarily precursors to successful integration of Internet capabilities for international business processes. On the contrary, international business experience and international networks actually lead to a reliance on traditional mechanisms of internationalisation and can dilute the development of Internet capabilities for international business processes.

Demystifying paradoxical characteristics of narcissistic personality disorder

This letter is aimed for psychotherapy clinicians and researchers who should acknowledge the relationship linking Kohut's self-psychology and Glasser's Choice theory that can demystify relationship difficulties and mental health problems in narcissistic personality disorder (NPD).

Characteristics of nontuberculous mycobacteria from a municipal water distribution system and their relevance to human infections

This thesis documented pathogenic species of nontuberculous mycobacteria in the Brisbane water distribution system. When water and shower aerosol strains were compared with human strains of mycobacteria, the study found that the likelihood of acquiring infection from municipal water was specific for four main species. The method for isolation of mycobacteria from water was refined, followed by sampling from 220 sites across Brisbane. A variety of species (incl 15 pathogens) were identified and genotypically compared to human strains. For M. abscessus and M. lentiflavum, water strains clustered with human strains. Pathogenic strains of M. kansasii were found, though non-pathogenic strains dominated. Waterborne strains of M. fortuitum differed to human strains. Extensive home sampling of 20 patients with NTM disease, supported the theory that the risk of acquiring NTM from water or shower aerosols appears species specific for M. avium, M. kansasii, M. lentiflavum and M. abscessus.

Biomechanical characteristics of peripheral diabetic neuropathy : a systematic review and meta-analysis of findings from the gait cycle, muscle activity and dynamic barefoot plantar pressure

Background: Diabetic peripheral neuropathy is an important cause of foot ulceration and limb loss. This systematic review and meta-analysis investigated the effect of diabetic peripheral neuropathy on gait, dynamic electromyography and dynamic plantar pressures. Methods: Electronic databases were searched systematically for articles reporting the effect of diabetic peripheral neuropathy on gait, dynamic electromyography and plantar pressures. Searches were restricted to articles published between January 2000 and April 2012. Outcome measures assessed included spatiotemporal parameters, lower limb kinematics, kinetics, muscle activation and plantar pressure. Meta-analyses were carried out on all outcome measures reported by ≥3 studies. Findings: Sixteen studies were included consisting of 382 neuropathy participants, 216 diabetes controls without neuropathy and 207 healthy controls. Meta-analysis was performed on 11 gait variables. A high level of heterogeneity was noted between studies. Meta-analysis results suggested a longer stance time and moderately higher plantar pressures in diabetic peripheral neuropathy patients at the rearfoot, midfoot and forefoot compared to controls. Systematic review of studies suggested potential differences in the biomechanical characteristics (kinematics, kinetics, EMG) of diabetic neuropathy patients. However these findings were inconsistent and limited by small sample sizes.; Interpretation: Current evidence suggests that patients with diabetic peripheral neuropathy have elevated plantar pressures and occupy a longer duration of time in the stance-phase during gait. Firm conclusions are hampered by the heterogeneity and small sample sizes of available studies. Interpretation: Current evidence suggests that patients with diabetic peripheral neuropathy have elevated plantar pressures and occupy a longer duration of time in the stance-phase during gait. Firm conclusions are hampered by the heterogeneity and small sample sizes of available studies.

Adhesive characteristics of low dimensional carbon nanomaterial on actin

The biosafety of carbon nanomaterial needs to be critically evaluated with both experimental and theoretical validations before extensive biomedical applications. In this letter, we present an analysis of the binding ability of two dimensional monolayer carbon nanomaterial on actin by molecular simulation to understand their adhesive characteristics on F-actin cytoskeleton. The modelling results indicate that the positively charged carbon nanomaterial has higher binding stability on actin. Compared to crystalline graphene, graphene oxide shows higher binding influence on actin when carrying positive surface charge. This theoretical investigation provides insights into the sensitivity of actin-related cellular activities on carbon nanomaterial.

Dynamic effects of electrical pitting in steam-turbine tilting-pad thrust-bearings

This paper merges the analysis of a case history and the simplified theoretical model related to a rather singular phenomenon that may happen in rotating machinery. Starting from the first, a small industrial steam turbine experienced a very strange behavior during megawatt load. When the unit was approaching the maximum allowed power, the temperature of the babbitt metal of the pads of the thrust bearing showed constant increase with an unrecoverable drift. Bearing inspection showed that pad trailing edge had the typical aspect of electrical pitting. This kind of damage was not reparable and bearing pads had to replaced. This problem occurred several times in sequence and was solved only by adding further ground brushes to the shaft-line. Failure analysis indicated electrodischarge machining as the root fault. A specific model, able to take into consideration the effect of electrical pitting and loading capacity decreasing as a consequence of the damage of the babbitt metal, is proposed in the paper and shows that the phenomenon causes the irretrievable failure of the thrust bearing.

Small signal stability analysis of power systems with high penetration of wind power

The integration of large amount of wind power into a power system imposes a new challenge for the secure and economic operation of the system. It is necessary to investigate the impacts of wind power generation on the dynamic behavior of the power system concerned. This paper investigates the impacts of large amount of wind power on small signal stability and the corresponding control strategies to mitigate the negative effects. The concepts of different types of wind turbine generators (WTGs) and the principles of the grid-connected structures of wind power generation systems are first briefly introduced. Then, the state-of-the-art of the studies on the impacts of WTGs on small signal stability as well as potential problems to be studied are clarified. Finally, the control strategies on WTGs to enhance power system damping characteristics are presented.