High temporal resolution observations of the pulsar microstructure at 102 MHz

We report observations of the microstructure of 7 pulsars at 102 MHz with a time resolution of up to 1 μs. We have detected fine pulse structure with a μs time-scale for all seven pulsars. We observe that interstellar scattering does not broaden the μs time-scale pulsar microstructure, and find structure of a time-scale much shorter than the interstellar scatter broadening. In addition to the previously known structure with time-scale τ_μ of tens of μs, we have detected structures with characteristic time-scale of a few μs, nearly equal to the reciprocal of the analysis bandwidth. This suggests that even shorter micropulses may exist.
Micropulses usually cluster in groups, each of duration tens to hundreds of μs, which may be identified as microstructure observed previously with smaller time resolution.
In addition to the previously known quasi-periodicity of hundreds of milliseconds, we reveal a structures with characteristic period of tens of μs. We observe structures with short quasi-periodicity to have a limited bandwidth. The characteristic period P_μ of these structures in PSR B0950+08 does not have a common value for different frequency regions in the same single pulse.
Scattering was revealed as a train of quasi-periodic micropulses with an exponentially damped envelope. The scatter-broadening and decorrelation bandwidth were measured. We report two time-scales of decorrelation bandwidth of pulsar PSR B0950+08 and propose two branches of Δν_d(ν) dependence.
The dispersion measure of PSR B0950+08 as DM= 2.9686 ± 0.0001 pc cm⁻³ has been determined.

System boundary selection in life-cycle inventories using hybrid approaches

Life-cycle assessment (LCA) is a method for evaluating the environmental impacts of products holistically, including direct and supply chain impacts. The current LCA methodologies and the standards by the International Organization for Standardization (ISO) impose practical difficulties for drawing system boundaries; decisions on inclusion or exclusion of processes in an analysis (the cutoff criteria) are typically not made on a scientific basis. In particular, the requirement of deciding which processes could be excluded from the inventory can be rather difficult to meet because many excluded processes have often never been assessed by the practitioner, and therefore, their negligibility cannot be guaranteed. LCA studies utilizing economic input−output analysis have shown that, in practice, excluded processes can contribute as much to the product system under study as included processes; thus, the subjective determination of the system boundary may lead to invalid results. System boundaries in LCA are discussed herein with particular attention to outlining hybrid approaches as methods for resolving the boundary selection problem in LCA. An input−output model can be used to describe at least a part of a product system, and an ISO-compatible system boundary selection procedure can be designed by applying hybrid input−output-assisted approaches. There are several hybrid input−output analysis-based LCA methods that can be implemented in practice for broadening system boundary and also for ISO compliance.

Integration and multiculturalism in music in Australian schools: has/can/should the leopard change its spots?

The 1960s saw a broadening of the offerings of music from other cultures in the materials and programs of the Australian Broadcasting Commission (ABC). This is a useful indicator for our changing perceptions. Since then, increasingly ‘authentic’ music materials have been available to primary classroom teachers, but how far have we really come? Blacking (1973) identified the difficulty of truly acquiring an understanding, skill and authenticity in the music of another culture. Blacking stressed the importance of music and musical acquisition occurring in a cultural context. In many cultures there is a clear link between the acquisition of musical and social skills. By removing music from one culture and presenting it in the symbolic gestures of another we may strip much of its meaning. It is very difficult for a member of one culture to comprehend the music and culture of another without understanding its social milieu. This is particularly true for musics from cultures removed from the Western music paradigm. It could be argued that the further we move from our cultural norm, the harder it is to produce authentic experiences for students and future experienced teachers. By considering the resources offered to teachers and teacher education students we can explore the attempts we have made, and continue to make, in our attempts to move from integration to multiculturalism. As a ‘work in progress’, this paper will consider the inclusion of African music in the nationally distributed ABC school singing books as a means of illustrating and marking change.

Stem cell research and ethics : a socio-economic and marketing perspective

This paper addresses the ethical and moral issues surrounding stem cell research (SCR) and development within the socio-economic and macro marketing environments. A two dimensional conceptual framework is developed towards broadening the understanding of the complexities of these issues in an international context. The conceptual model captures the two dimensions of narrow moral/ethical to broader imperatives and the cost-benefits realm of SCR. Four quadrants emerge within these two dimensions which are likely to help identify the dominant views and the people associating themselves with these views in terms of their demographics and psychographic characteristics. These findings have important socio-economic and marketing implications which are highlighted in the paper.

11B nuclear magnetic resonance study of boron nitride nanotubes prepared by mechano-thermal method

We reported ¹¹B nuclear magnetic resonance studies of boron nitride (BN) nanotubes prepared by mechano-thermal route. The NMR lineshape obtained at 192.493 MHz (14.7 T) was fitted with two Gaussian functions, and the ¹¹B nuclear magnetization relaxations were satisfied with the stretched–exponential function, exp[-(tlT₁)^(D+1)/6] (D: space dimension) at all temperatures. In addition, the temperature dependence of spin–lattice relaxation rates was well described by T_i^-1 = aT (a: constant, T: temperature) and could be understood in terms of direct phonon process. All the 11BNMR results were explained by considering the inhomogeneous distribution of the paramagnetic metal catalysts, such as α-Fe, Fe–N, and Fe₂ B, that were incorporated during the process of high-energy ball milling of boron powder and be synthesized during subsequent thermal annealing. X-ray powder diffraction as well as electron paramagnetic resonance (EPR) on BN nanotubes were also conducted and the results obtained supported these conclusions.

Global and regional dispersion of publishing in the field of international marketing

This paper empirically examines the research productivity of academic institutions in the leading international marketing journals, leading generalist marketing journals, and leading international business journals between the years 1999 and 2003 from a regional and country-specific perspective. The research found that across the three groups of journals, the majority of works were authored by academics at institutions located in North America, although North Americans contribute significantly less in the international marketing and international business journals than leading generalist marketing journals. The findings suggest that there is a broadening of non-U.S. influence within the international marketing and international business journals, which should lead to a broadening of international marketing theory.

Incongruence between nurses' and patients' understandings and expectations of rehabilitation

Aims and objectives. To explore nurses' understandings and expectations of rehabilitation and nurses' perceptions of patients' understandings and expectations of rehabilitation.
Background. Within the context of a broadening appreciation of the benefits of rehabilitation, interest in the nature of rehabilitation is growing. Some believe that rehabilitation services do not adequately meet the needs of patients. Others are interested in the readiness of patients to participate in rehabilitation.
Design. Qualitative.
Method. Grounded theory using data collected during interviews with nurses in five inpatient rehabilitation units and during observation of the nurses' everyday practice.
Findings. According to nurses working in inpatient rehabilitation units, there is a marked incongruence between nurses' understandings and expectations of rehabilitation and what they perceive patients to understand and expect.
Conclusion. Given these different understandings, an important nursing role is the education of patients about the nature of rehabilitation and how to optimise their rehabilitation.

Relevance to clinical practice. Before patients are transferred to rehabilitation, the purpose and nature of rehabilitation, in particular the roles of patients and nurses, needs to be explained to them. The understandings of rehabilitation that nurses in this study possessed provide a framework for the design of education materials and orientation programmes that inform patients (and their families) about rehabilitation. In addition, reinforcement of the differences between acute care and rehabilitation will assist patients new to rehabilitation to understand the central role that they themselves can play in their recovery.

Design and analysis of hull configurations for a low-cost, autonomous underwater robot as an enabling technology for system of system applications

The objective of this research is to model and analyze candidate hull configurations for a low-cost, modular, autonomous underwater robot. As the computational power and speed of microprocessors continue to progress, we are seeing a growth in the research, development, and the utilization of underwater robots. The number of applications is broadening in the R&D and science communities, especially in the area of multiple, collaborative robots. These underwater collaborative robots represent an instantiation of a System of Systems (SoS). While each new researcher explores a unique application, control method, etc. a new underwater robot vehicle is designed, developed, and deployed. This sometimes leads to one-off designs that are costly. One limit to the wide-scale utilization of underwater robotics is the cost of development. Another limit is the ability to modify the configuration for new applications and evolving requirements. Consequently, we are exploring autonomous underwater vehicle (AUV) hull designs towards the goal of modularity, vehicle dexterity, and minimizing the cost. In our analysis, we have employed 3D solid modeling tools and finite element methods. In this paper we present our initial results and discuss ongoing work.

Anger and indigenous men : understanding and responding to violent behaviour

This book is for social work and criminal justice practitioners who wish to develop culturally appropriate and effective programs for reducing anger-related violence perpetrated by Indigenous men. It places cultural context at the heart of any intervention, broadening the focus from problematic behaviour to a more holistic notion of well-being.

Practitioner perceptions of sustainability in the Building Code of Australia

Buildings have a significant impact on environmental quality, resource use, human health and productivity. One definition of sustainable building is that which meets current building needs and reduces impacts on future generations by integrating building materials and methods that promote environmental quality, economic vitality, and social benefit’ (City of Seattle, 2006). In response to a changing view of
sustainability the Building Code of Australia (BCA) adopted energy measures in 2005 to residential buildings and, in 2006, to Class 1 – 9 buildings. In many respects the measures represented a watershed for the Australian Building Regulations which had not included sustainability within the BCA. The goals of the BCA are to enable the achievement and maintenance of acceptable standards of structural sufficiency, safety (including safety from fire), health and amenity for the benefit of the community now and in the future (ABCB, 2004a). As with any change some Building Surveyors and construction practitioners viewed these measures with apprehension. How would the measures be assessed? Furthermore, was the BCA the appropriate place for these measures and was this a broadening of the scope of the building regulations beyond
its traditional remit of health and life safety in buildings? This research used a questionnaire survey the canvass the views and perceptions of Building Surveyors and Architects with regards to sustainability and the BCA in 2006.

Studies on the behaviour of polystyrene in reversed phase chromatography

Polystyrene behaviour in reversed phase high performance liquid chromatography was influenced mainly by the solvent system, but secondary affects were observed depending on the stationary phase. A variety of reversed phase columns were investigated using mobile phase combinations of dichlorom ethane-methanol, dichloromethane-acetonitrile, ethyl acetate-methanol and ethyl acetate-acetonitrile. Several different modes of behaviour were observed depending on the polymer solubility in the solvent system. In the dichloromethane-methanol solvent system, polymer-stationary phase interactions only occurred when the molecules had pore access. Retention of excluded polystyrene depended on the kinetics of precipitation and redissolution of the polymer. Peak splitting and band broadening occurred when the kinetics were slow and molecular weight separations were limited !o oligomers and polystyrenes lower than 5-10(4) dalton. Excellent molecular weight separations of polystyrenes were obtained using gradient elution reversed phase chromatography with a dichloromethane-acetonitrile mobile phase on C18 columns. The retention was based on polymer-stationary phase interactions regardless of the column pore size. Separations were obtained on large diameter pellicular adsorbents that were almost as good as those obtained on porous adsorbents, showing that pore access was not essential for the retention of high molecular weight polystyrenes. In the best example, the separation ranged from the monomer to 10(6) dalton in a single analysis. Very little adsorption of excluded polymers was observed on C8 or phenyl columns. Polystyrene molecular weight separations to 7-10(5) dalton were obtained in an ethyl acetate-acetonitrile solvent system on C18 columns. Adsorption was responsible for retention. When an ethyl acetate-methanol solvent system was used, no molecular weight separations were obtained because of complex peak splitting. Reversed phase chromatography was compared to size exclusion chromatography for the analysis of polydisperse polystyrenes. Similar results were obtained using both methods. However, the reversed phase method was less sensitive to concentration effects and gave better resolution.

Ion transport in polymer electrolytes containing nanoparticulate TiO2 : The influence of polymer morphology

Recent studies have shown that composite polymer electrolytes, formed by dispersing nanosized ceramic particles in polyether-based electrolytes, have improved ion transport properties as compared to their unfilled analogues. In the present study polymer electrolytes with different loadings of nano-sized ceramic particles (TiO₂) and different polymer chemistry and morphology have been investigated. Of special interest are filler induced effects on polymer, solvent and cationic mobility. Partly crystalline polymer electrolytes based on poly(ethylene oxide) have been compared to fully amorphous polymer electrolytes based on a polyether urethane, as well as gel electrolytes based on PMMA. ⁷Li pfg-NMR, linewidth and spin–spin relaxation times as well as ¹H pfg-NMR and spin–spin relaxation times, were measured as a function of temperature and composition. The ¹H spin–spin relaxation measurements reveal increased average polymer mobility with the addition of filler up to a maximum at 4 and 8 wt.% TiO₂ for the fully amorphous and the partly crystalline electrolytes, respectively. The ⁷Li linewidth measurements for the fully amorphous system show a broadening of the linewidth with addition of filler. Based on variable temperature measurements this broadening is interpreted as a result of the inhomogeneity introduced by the filler particles. Pulsed field gradient (pfg) diffusion measurements were employed to determine ion and solvent self-diffusion coefficients. In the case of the PMMA-based gel electrolyte and the fully amorphous electrolytes enhanced cation self-diffusion was observed upon addition of TiO₂.

A study of acid/base treatments of polypyrrole films using 13C n.m.r. spectroscopy

Electrodeposited polypyrrole films prepared with paratoluenesulfonate (pTS), dodecylsulfate (DDS) and perchlorate anions were treated with acidic and basic solutions, and their structure was investigated by 13C solid state n.m.r. spectroscopy. This technique has confirmed that pTS is completely removed from the film in both acidic and basic solutions whilst DDS is only partially removed and tends to decompose upon treatment with H2SO4. The appearance of shoulders at 143 ppm upon treatment with 0.5 M base indicates formation of a quinoid pyrrole structure. Substitution on the β-carbon by OH cannot be confirmed from the present spectra. Stronger base causes a more dramatic change in the polypyrrole backbone with an obvious increase in the electron density on the β-carbons, consistent with the reduction of the carbon backbone. There is no indication of quinoid units in this case. Acid treatments result in considerable broadening of the main 127 ppm polypyrrole peak.

Composition effects in polyetherurethane-based solid polymer electrolytes

Nuclear magnetic resonance spectroscopy (n.m.r.), dynamic mechanical thermal analysis (d.m.t.a.) and AC impedance techniques have been used in combination to probe the effect of electrolyte composition in an archetypal solid polymer electrolyte (SPE). A series of solid polymer electrolytes (SPEs) based on a urethane-crosslinked trifunctional poly(ethylene glycol) polymer host containing dissolved ionic species (LiClO₄ and LiCF₃SO₃) have been studied. D.m.t.a. has established that increasing LiClO₄ concentration causes a decrease in the polymer segmental mobility, owing to the formation of transient crosslinks via cation-polymer interaction. Investigation of the distribution of mechanical/structural relaxation times for the LiClO₄/polymer complex with d.m.t.a. reveals that increasing LiClO₄ concentration causes a slight broadening of the distribution, indicating a more heterogeneous environment. Results of n.m.r. ⁷Li T₁ and T₂ relaxation experiments support the idea that higher salt concentrations encourage ionic aggregation. This is of critical importance in determining the conductivity of the material since it affects the number of charge carriers available. Introduction of the plasticiser tetraglyme into the LiClO₄-based SPEs suppresses the glass transition temperature of the SPE, and causes a significant broadening of the relaxation time distribution (as measured by d.m.t.a.).

Quantifying rubber degradation using NMR

Ageing can lead to the degradation of the tensile properties of natural rubber. The ageing process causes changes in the polymer segmental motion as well as the chemical structure, both of which can be monitored using nuclear magnetic resonance (NMR) spectroscopy. This work demonstrates that NMR can quantify rubber degradation due to ageing, and also that relatively simple NMR equipment can be used. This simpler equipment can be made portable and so could give a simple and fast indication of the condition of rubber in service. The 1H NMR transverse relaxation time, T2, and the 13C NMR spectrum using cross polarization and magic angle spinning (CP MAS) for samples taken at various levels of a degraded natural rubber liner were compared. These experiments showed that, as the level of degradation increased, the 1H NMR transverse relaxation time decreased. The 13C spectra showed considerable peak broadening, indicative of decreased mobility with increased level of degradation as well as the presence of degradation products. Further investigations using lower powered NMR equipment to measure the 1H NMR transverse relaxation times of two different series of natural rubbers were also performed. This work has shown that this simpler method is also sensitive to structural and mechanical property changes in the rubber. This method of monitoring rubber degradation could lead to the non-destructive use of NMR to determine the condition of a part in service.