IEEE 802.11p empirical performance model from evaluations on test tracks

IEEE 802.11p is the new standard for intervehicular communications (IVC) using the 5.9 GHz frequency band; it is planned to be widely deployed to enable cooperative systems. 802.11p uses and performance have been studied theoretically and in simulations over the past years. Unfortunately, many of these results have not been confirmed by on-tracks experimentation. In this paper, we describe field trials of 802.11p technology with our test vehicles; metrics such as maximum range, latency and frame loss are examined. Then, we propose a detailed modelisation of 802.11p that can be used to accurately simulate its performance within Cooperative Systems (CS) applications.

University Students Depression Inventory : measurement model and psychometric properties

Depression is a serious condition that impacts the academic success and emotional well-being of the university students globally. Keeping in view the debilitating nature of this condition, the present study examined the stability of the factor structure and psychometric properties of the University Student Depression Inventory (USDI; Khawaja and Bryden, 2006). There is a need to translate and validate the scale for Persian speaking students, who live in Iran, its neighboring countries and in many other Western countries. The scale was translated into the Persian language and was used as part of a battery consisting of the scales measuring suicide, depression, stress, happiness and academic achievement. The battery was administered to 359 undergraduate students, and an additional 150 students who had been referred to the mental health center of the University of Tehran as clinical sample. Confirmatory factor analysis upheld the original three-factor structure. The results exhibited internal consistency, test-retest reliability, convergent, and divergent validity, and discriminant validity. There were gender differences and male had higher mean scores on Lethargy, Cognitive\emotion, and Academic motivation subscales than female students. Findings supported the Persian version of the USDI for cross-cultural use as a valid and reliable measure in the diagnosis of depression.

Integrin-functionalized artificial membranes as test platforms for monitoring small integrin ligand binding by surface plasmon-enhanced fluorescence spectroscopy

The design and synthesis of molecularly or supramolecularly defined interfacial architectures have seen in recent years a remarkable growth of interest and scientific research activities for various reasons. On the one hand, it is generally believed that the construction of an interactive interface between the living world of cells, tissue, or whole organisms and the (inorganic or organic) materials world of technical devices such as implants or medical parts requires proper construction and structural (and functional) control of this organism–machine interface. It is still the very beginning of generating a better understanding of what is needed to make an organism tolerate implants, to guarantee bidirectional communication between microelectronic devices and living tissue, or to simply construct interactive biocompatibility of surfaces in general. This exhaustive book lucidly describes the design, synthesis, assembly and characterization, and bio-(medical) applications of interfacial layers on solid substrates with molecularly or supramolecularly controlled architectures. Experts in the field share their contributions that have been developed in recent years.

Investigation of the effects of various types of wind turbine generators on power-system stability

It has become more and more demanding to investigate the impacts of wind farms on power system operation as ever-increasing penetration levels of wind power have the potential to bring about a series of dynamic stability problems for power systems. This paper undertakes such an investigation through investigating the small signal and transient stabilities of power systems that are separately integrated with three types of wind turbine generators (WTGs), namely the squirrel cage induction generator (SCIG), the doubly fed induction generator (DFIG), and the permanent magnet generator (PMG). To examine the effects of these WTGs on a power system with regard to its stability under different operating conditions, a selected synchronous generator (SG) of the well-known Western Electricity Coordinating Council (WECC three-unit nine-bus system and an eight-unit 24-bus system is replaced in turn by each type of WTG with the same capacity. The performances of the power system in response to the disturbances are then systematically compared. Specifically, the following comparisons are undertaken: (1) performances of the power system before and after the integration of the WTGs; and (2) performances of the power system and the associated consequences when the SCIG, DFIG, or PMG are separately connected to the system. These stability case studies utilize both eigenvalue analysis and dynamic time-domain simulation methods.

Wide-area control of aggregated power systems

This paper proposes a new method for stabilizing disturbed power systems using wide area measurement and FACTS devices. The approach focuses on both first swing and damping stability of power systems following large disturbances. A two step control algorithm based on Lyapunov Theorem is proposed to be applied on the controllers to improve the power systems stability. The proposed approach is simulated on two test systems and the results show significant improvement in the first swing and damping stability of the test systems.

Wide area controls for transient and dynamic stability enhancement

This paper presents a study done into the effectiveness of using local acceleration measurements vs. remote angle measurements in providing stabilising control via SVCs following large disturbances. The system studied was an analogue of the Queensland-New South Wales Interconnection (QNI) and involved the control of an existing Static Var Compensators (SVC) at Sydney West. This study is placed in the context of wide area controls for large systems using aggregated models for groups of machines.

Identification of reduced models of power system areas using phasor measurement units

In this paper an approach is presented for identification of a reduced model for coherent areas in power systems using phasor measurement units to represent the inter-area oscillations of the system. The generators which are coherent in a wide range of operating conditions form the areas in power systems and the reduced model is obtained by representing each area by an equivalent machine. The reduced nonlinear model is then identified based on the data obtained from measurement units. The simulation is performed on three test systems and the obtained results show high accuracy of identification process.

Switching radical stability by pH-induced orbital conversion

In most radicals the singly occupied molecular orbital (SOMO) is the highest-energy occupied molecular orbital (HOMO); however, in a small number of reported compounds this is not the case. In the present work we expand significantly the scope of this phenomenon, known as SOMO-HOMO energy-level conversion, by showing that it occurs in virtually any distonic radical anion that contains a sufficiently stabilized radical (aminoxyl, peroxyl, aminyl) non-pi-conjugated with a negative charge (carboxylate, phosphate, sulfate). Moreover, regular orbital order is restored on protonation of the anionic fragment, and hence the orbital configuration can be switched by pH. Most importantly, our theoretical and experimental results reveal a dramatically higher radical stability and proton acidity of such distonic radical anions. Changing radical stability by 3-4 orders of magnitude using pH-induced orbital conversion opens a variety of attractive industrial applications, including pH-switchable nitroxide-mediated polymerization, and it might be exploited in nature.

Bauxite residue neutralisation precipitate stability in acidic environments

This investigation used a combination of techniques, such as X-ray diffraction, inductively coupled plasma optical emission spectroscopy and infrared spectroscopy, to determine the dissolution mechanisms of the Bayer precipitate and the associated rate of dissolution in acetic, citric and oxalic acid environments. The Bayer precipitate is a mixture of hydrotalcite, calcium carbonate and sodium chloride that forms during the seawater neutralisation of Bayer liquors (waste residue of the alumina industry). The dissolution rate of a Bayer precipitate is found to be dependent on (1) the strength of the organic acid and (2) the number of donating H+ ions. The dissolution mechanism for a Bayer precipitate consists of several steps involving: (1) the dissolution of CaCO3, (2) formation of whewellite (calcium oxalate) when oxalic acid is used and (3) multiple dissolution steps for hydrotalcite that are highly dependent on the pH of solution. The decomposition of the Al–OH hydrotalcite layers resulted in the immediate formation of Al(OH)3, which is stable until the pH decreases below 5.5. This investigation has found that the Bayer precipitate is stable across a wide pH range in the presence of common organic acids found in the rhizosphere, and that initial decomposition steps are likely to be beneficial in supporting plant growth through the release of nutrients such as Ca2þ and Mg2þ.

Design Pressure Test 2013 Workshop

Design Pressure Test 2013 was a full-day intensive design immersion creative event run on Saturday 3 August 2013, at the QUT Faculty of Creative Industries J Block Design Lab Workshop in Brisbane, Australia, for 25 self-selected high-achieving junior and middle school (year 5-9) students, as part of the Queensland Academies ‘Young Scholars’ Program. Facilitated by tertiary interior design, fashion design and industrial design educators, technicians and six tertiary interior design and fashion design students, the workshop explored design process, environmental impact, the material properties and structural integrity of cardboard, construction techniques, and the production and evaluation of furniture design prototypes. This action research study aimed to facilitate an awareness in young people, of the role and scope of design within our society, the environmental ramifications of design decisions, and the value of design thinking skills in generating strategies to solve basic to complex challenges. It also aimed to investigate the value of collaboration between junior and middle school students, tertiary design educators and students and industry professionals in design awareness, and inspiring post-secondary pathways and idea generation for education. During the creative event, students utilised mathematics skills and developed sketching, making, communication, presentation and collaboration skills to improve their design process, while considering social, cultural and environmental opportunities. Through a series of hands-on collaborative design experiments, participants explored in teams of five, the opportunities available using cardboard as a material – inspiring both functional and aesthetic design solutions. Underpinned by the State Library of Queensland Design Minds Website ‘inquire, ideate and implement’ model of design thinking, the experiments culminated in the development of a detailed client brief, the design and fabrication of a furniture item for seating, and then a team presentation of prototypes to a panel of judges from the professions of architecture, interior design and industrial design, viewed also by parents. The final test for structural integrity was measured by the hoisting down of an adult body weight onto the fabricated seat. The workshop was filmed for the television program ‘Totally Wild’ for dissemination nationally (over 200,000 viewing audience) of the value of design and the Design Minds model to a wider target youth audience.

IT governance stability in a political changing environment : exploring potential impacts in the public sector

Public sector organisations (PSOs) operate in information-intensive environments often within operational contexts where efficiency is a goal. What's more, the rapid adoption of IT is expected to facilitate good governance within public sector organisations but it often clashes with the bureaucratic culture of these organisations. Accordingly, models such as IT Governance (ITG) and government reform -in particular the new public management (NPM)- were introduced in PSOs in an effort to address the inefficiencies of bureaucracy and under performance. This work explores the potential effect of change in political direction and policy on the stability of IT governance in Australian public sector organisations. The aim of this paper is to examine implications of a change of government and the resulting political environment on the effectiveness of the audit function of ITG. The empirical data discussed here indicate that a number of aspects of audit functionality were negatively affected by change in political direction and resultant policy changes. The results indicate a perceived decline in capacity and capability which in turn disrupts the stability of IT governance systems in public sector organisations.

Use of cadavers and anthropometric test devices (ATDs) for assessing lower limb injury outcome from under‐vehicle explosions

Lower extremities are particularly susceptible to injury in an under‐vehicle explosion. Operational fitness of military vehicles is assessed through anthropometric test devices (ATDs) in full‐scale blast tests. The aim of this study was to compare the response between the Hybrid‐III ATD, the MiL‐Lx ATD and cadavers in our traumatic injury simulator, which is able to replicate the response of the vehicle floor in an under‐vehicle explosion. All specimens were fitted with a combat boot and tested on our traumatic injury simulator in a seated position. The load recorded in the ATDs was above the tolerance levels recommended by NATO in all tests; no injuries were observed in any of the 3 cadaveric specimens. The Hybrid‐III produced higher peak forces than the MiL‐Lx. The time to peak strain in the calcaneus of the cadavers was similar to the time to peak force in the ATDs. Maximum compression of the sole of the combat boot was similar for cadavers and MiL‐Lx, but significantly greater for the Hybrid‐III. These results suggest that the MiL‐Lx has a more biofidelic response to under‐vehicle explosive events compared to the Hybrid‐III. Therefore, it is recommended that mitigation strategies are assessed using the MiL‐Lx surrogate and not the Hybrid‐III.

Stability of the bituminous coal microstructure upon exposure to high pressures of helium

Small-angle neutron scattering (SANS) and ultra-small-angle neutron scattering (USANS) measurements of the structure of two Australian bituminous coals (particle size of 1-0.5 mm) before, during, and after exposure to 155 bar of helium were made to identify any effects of pressure alone on the pore size distribution of coal and any irreversible effects upon exposure to high pressures of helium in the pore size range from 3 nm to 10 μm. No irreversible effects upon exposure were identified for any pore size. No effects of pressure on pore size distribution were observed, except for a small effect at a pore size of about 2 μm for one coal. This study provides a convenient baseline for SANS and USANS investigations on sorption of gases at elevated pressures on coals, by distinguishing between the effect of pressure alone on coal pore size distribution and against the effect of the gas to be investigated.

New criterion for the stability of a human body in floodwaters

The authors must be congratulated for their original and important study. The flooding of urbanised areas constitutes a hazard to the population and infrastructure. Floods through inundated urban environments have been studied only recently and few considered the potential impact of flowing waters on pedestrians...

Distamycin A affects the stability of NF-kappaB p50-DNA complexes in a sequence-dependent manner

The effect of two different DNA minor groove binding molecules, Hoechst 33258 and distamycin A, on the binding kinetics of NF-κB p50 to three different specific DNA sequences was studied at various salt concentrations. Distamycin A was shown to significantly increase the dissociation rate constant of p50 from the sequences PRDII (5′-GGGAAATTCC-3′) and Ig-κ B (5′-GGGACTTTCC-3′) but had a negligible effect on the dissociation from the palindromic target-κB binding site (5′-GGGAATTCCC-3′). By comparison, the effect of Hoechst 33258 on binding of p50 to each sequence was found to be minimal. The dissociation rates for the protein–DNA complexes increased at higher potassium chloride concentrations for the PRDII and Ig-κB binding motifs and this effect was magnified by distamycin A. In contrast, p50 bound to the palindromic target-κB site with a much higher intrinsic affinity and exhibited a significantly reduced salt dependence of binding over the ionic strength range studied, retaining a KD of less than 10 pM at 150 mM KCl. Our results demonstrate that the DNA binding kinetics of p50 and their salt dependence is strongly sequence-dependent and, in addition, that the binding of p50 to DNA can be influenced by the addition of minor groove-binding drugs in a sequence-dependent manner.