Evaluation of police service service delivery in the southern Gold Coast area

Project examines how residential and business sectors of the community in the southern Gold Coast perceive the police service provided to them and records the level of satisfaction with that service. The history of policing is also discussed, from the early convict days to the methods employed by the Queensland Police Service.. This study explores how the residential and business sectors of the community in the southern Gold Coast area perceive the police service provided to them. The study also records the community level of satisfaction with that service. To provide a .context for theses community outcomes, contemporary policing issues in Australia are discussed, in particular how policing has developed from the early convict days to the current methods used by the Queensland Police Service to deliver its service. This study discusses such issues in policing as technology and the current concepts underlying police response times and police numbers and the impact this has on crime and community satisfaction levels. International concepts in crime prevention and community policing are explored and are highlighted by examples of community policing case studies conducted by the Queensland Police Service. Various studies relating to crime prevention are reviewed and the community fear of crime is discussed. Of particular interest is the expansion and theoretical considerations of situational crime prevention as relates to routine crime prevention activity and the role of guardians. The role of police as guardians for break and enter crime is of particular interest. The study concludes that a police response in this role is inadequate and alternative strategies must be implemented. Alternative strategies of guardianship could find the police implementing activities that empower the community with knowledge and resources to perform the role of guardians against break and enter crime themselves

Searching for wide-orbit gravitational instability protoplanets with ALMA in the dust continuum

Searches for young gas giant planets at wide separations have so far focused on techniques appropriate for compact (Jupiter-sized) planets. Here, we point out that protoplanets born through gravitational instability (GI) may remain in an initial pre-collapse phase for as long as the first 105-107 yr after formation. These objects are hundreds of times larger than Jupiter and their atmospheres are too cold (T ∼tens of K) to emit in the near-infrared or Hα via accretion shocks. However, it is possible that their dust emission can be detected with Atacama Large Millimeter/submillimeter Array (ALMA), even around Classes I and II protoplanetary discs. In this paper, we produce synthetic observations of these protoplanets. We find that making a detection in a disc at 140 pc would require a few hundred minutes of ALMA band 6 observation time. Protoplanets with masses of 3-5 MJ have the highest chance of being detected; less massive objects require unreasonably long observation times (1000 min), while more massive ones collapse into giant planets before 105 yr. We propose that high-resolution surveys of young (105-106 yr), massive and face on discs offer the best chance for observing protoplanets. Such a detection would help to place constraints on the protoplanet mass spectrum, explain the turnover in the occurrence frequency of gas giants with system metallicity and constrain the prevalence of GI as a planet formation mechanism. Consistent lack of detection would be evidence against GI as a common planet formation mechanism

A rapid viscous-inviscid interaction method for the preliminary design of s-shaped transition ducts

For preliminary design of compressor transition ducts, knowledge-based tools for the rapid assessment of aerodynamic performance of S-shaped ducts are not currently available in the open literature. This is due to the highly complex flow developing under the combined influence of pressure gradients and streamline curvature. This paper presents a new approach enabling an agile design process avoiding premature use of timeconsuming high-fidelity CFD calculations. The features of a 2D axisymmetric incompressible steady flow field are captured with a semi-analytical viscous inviscid interaction method. A potential core, based on streamline curvature and implicit velocity profile by parametric spline reconstruction, is coupled to an integral method predicting the turbulent boundary layer growth up to separation. The shear stress distribution is generated by a modified mixing length model for strongly curved flows and wall shear stress closure is performed by inverse calculation of a composite law-of-the-wall. When compared to CFD, the aerodynamic loading is generally predicted to within ± 3% but convergence is achieved 20 times faster

Experimental investigation of secondary flows and length reduction for a low-pressure compressor transition duct

The need to reduce fuel-burn and CO2 emissions, is pushing turbofan engines towards geared architectures with very high bypass-ratios and small ultra-high-pressure ratio core engines. However, this increases the radial offset between compressor spools and leads to a more challenging design for the compressor transition ducts. To minimise weight, these ducts must achieve the radial turning in as short a length, but this leads to strong curvature induced pressure gradients, increased aerodynamic loading and likelihood of flow separation. For the duct connecting the low-pressure fan to the engine core this is further complicated by the poor-quality flow generated at the fan hub which is characterised by low total pressure and large rotating secondary flow structures. In a previous paper the authors numerically designed modifications to an existing test facility such that the rotor would produce these large structures. The current paper presents an experimental evaluation of the new rotor design and examines the effect of the increased loss cores on the performance of a set of engine sector stators (ESS) or outlet guide vanes (OGV) and an engine representative compressor transition duct. Aerodynamic data were collected via miniature five-hole probes, for the time-averaged pressure and velocity field, and phaselocked hot-wire anemometry to capture the rotating secondary flows. Analysis of the experimental data showed that these structures promoted mixing through the ESS increasing the momentum exchange between the core and boundary layer flows. Measurements within the duct showed a continued reduction in the hub-wall boundary layer suggesting that the duct has been moved further from separation. Consequently, a more aggressive duct with 12.5% length reduction was designed and tested with the data confirming that the more aggressive duct remained fully attached. Total pressure loss data suggested a slight increase in loss over the vane row but that was offset by a reduced loss in the duct due to improved flow quality and reduced length. Overall, the 12.5% length reduction represents a significant cumulative effect in terms of reduced fuel burn and CO2 over the operational life of an engine

The Temporal Requirements of Directly Observing Self-gravitating Spiral Waves in Protoplanetary Disks with ALMA

We investigate how the detectability of signatures of self-gravity in a protoplanetary disk depends on its temporal evolution. We run a one-dimensional model for secular timescales to follow the disk mass as a function of time. We then combine this with three-dimensional global hydrodynamics simulations that employ a hybrid radiative transfer method to approximate realistic heating and cooling. We simulate ALMA continuum observations of these systems and find that structures induced by the gravitational instability (GI) are readily detectable when q = Mdisk/M* 0.25 and Router 100 au. The high accretion rate generated by gravito-turbulence in such a massive disk drains its mass to below the detection threshold in ∼104 years, or approximately 1% of the typical disk lifetime. Therefore, disks with spiral arms detected in ALMA dust observations, if generated by self-gravity, must either be still receiving infall to maintain a high q value, or have just emerged from their natal envelope. Detection of substructure in systems with lower q is possible, but would require a specialist integration with the most extended configuration over several days. This disfavors the possibility of GI-caused spiral structure in systems with q < 0.25 being detected in relatively short integration times, such as those found in the DSHARP ALMA survey. We find no temporal dependence of detectability on dynamical timescales

Predicting the Kinematic Evidence of Gravitational Instability

Observations with the Atacama Large Millimeter/Submillimeter Array (ALMA) have dramatically improved our understanding of the site of exoplanet formation: protoplanetary disks. However, many basic properties of these disks are not well understood. The most fundamental of these is the total disk mass, which sets the mass budget for planet formation. Disks with sufficiently high masses can excite gravitational instability and drive spiral arms that are detectable with ALMA. Although spirals have been detected in ALMA observations of the dust, their association with gravitational instability, and high disk masses, is far from clear. Here we report a prediction for kinematic evidence of gravitational instability. Using hydrodynamics simulations coupled with radiative transfer calculations, we show that a disk undergoing such instability has clear kinematic signatures in molecular line observations across the entire disk azimuth and radius, which are independent of viewing angle. If these signatures are detected, it will provide the clearest evidence for the occurrence of gravitational instability in planet-forming disks, and provide a crucial way to measure disk masses

The chemistry of protoplanetary fragments formed via gravitational instabilities

In this paper, we model the chemical evolution of a 0.25 M⊙ protoplanetary disc surrounding a 1 M⊙ star that undergoes fragmentation due to self-gravity. We use smoothed particle hydrodynamics including a radiative transfer scheme, along with a time-dependent chemical evolution code to follow the composition of the disc and resulting fragments over approximately 4000 yr. Initially, four quasi-stable fragments are formed, of which two are eventually disrupted by tidal torques in the disc. From the results of our chemical modelling, we identify species that are abundant in the fragments (e.g. H2O, H2S, HNO, N2, NH3, OCS, SO), species that are abundant in the spiral shocks within the disc (e.g. CO, CH4, CN, CS, H2CO) and species that are abundant in the circumfragmentary material (e.g. HCO+). Our models suggest that in some fragments it is plausible for grains to sediment to the core before releasing their volatiles into the planetary envelope, leading to changes in, e.g., the C/O ratio of the gas and ice components. We would therefore predict that the atmospheric composition of planets generated by gravitational instability should not necessarily follow the bulk chemical composition of the local disc material