Development of a renewable hybrid power plant with extended utilization of pumped storage unit equipment

The scheme of a renewable hybrid power plant with the extended use of the installed equipment of the pumped storage unit for the conversion of the photovoltaic and wind generators direct current to the alternating one is proposed. The scheme is based on existing components with widely used proven technology. To output the power of solar and wind generators to the grid and for DC to AC conversion, a synchronous generator of the pumped storage unit is used in addition to grid inverters. An induction motor, powered through a variable frequency drive from a common DC bus, is used together with a hydraulic turbine to rotate the generator. In addition, batteries and capacitors banks are connected to the DC bus. The possibility of using various types of electric machines to drive a synchronous generator is analyzed and the preference of an induction motor is shown. The response of an induction motor to rotational speed fluctuations is modeled and its capability to participate in the network frequency regulation is shown. With the example of a typical daily load and generation profile, it is shown that the proposed solution for DC to AC conversion has an efficiency close to that of the grid inverter. The proposed scheme of the hybrid power plant can increase the reliability of renewable energy sources and the stability of the network frequency. This is achieved due to increasing the inertia of the rotating masses in the power system, the power factor control capabilities of the synchronous generator and the proper response of induction motor to rapid fluctuations of the rotation speed. The creation of such hybrid power plants opens the way for a further increase in the share of renewable energy sources in the power system.Запропоновано схему гібридної відновлюваної електричної станції з розширеним використанням встановленого обладнання гідроакумулюючого блока для перетворення постійного струму фотоелектричних та вітрових генераторів в змінний. Схема базується на наявних компонентах з широко використовуваною відпрацьованою технологією. Для видачі потужності та перетворення постійного струму сонячних та вітрових генераторів в змінний окрім мережевих інверторів використовується синхронний генератор гідроакумулюючого блоку. Для обертання генератора крім гідротурбіни також використовується асинхронний двигун, підключений через частотно-регульований привод до загальної шини постійного струму станції. Крім того, до шини постійного струму підключені електрохімічні акумулятори і батареї конденсаторів. Проаналізовано можливість використання різних типів електричних машин для приводу синхронного генератора і показано перевагу асинхронного двигуна. Змодельовано реакцію асинхронного двигуна на коливання швидкості обертання і показано його здатність брати участь в регулюванні частоти мережі. На прикладі типового добового графіка навантаження і генерації показано, що запропоноване рішення по перетворенню постійного струму в змінний має ККД, близький до ККД мережевого інвертора. Запропонована схема гібридної станції дозволяє підвищити надійність роботи відновлюваних джерел енергії і стабільність частоти мережі. Це досягається завдяки збільшенню інерції обертових мас в енергосистемі, можливості управління коефіцієнтом потужності синхронного генератора і властивій асинхронному двигуну реакції на коливання швидкості обертання. Створення таких гібридних станцій відкриває шлях до подальшого збільшення частки відновлюваних джерел в енергосистемі

Feasibility and acceptability of a culturally tailored physical activity intervention for Arab-Australian women

Background: Despite being one of the largest migrant groups in Australia, few physical activity interventions exist for Arab-Australians. The primary aim of this study was to test the feasibility and acceptability of a 12-week culturally tailored physical activity intervention for Arab-Australian women. Methods: This study used a single-group pretest–posttest design, and was informed by extensive formative research and consultation involving the Arab-Australian community. Participants were insufficiently active Arab-Australian women aged 35–64 with no current illness or injury that would limit physical activity participation. The intervention comprised 6 face-to-face physical activity and education sessions over 12 weeks. The intervention was conducted at 2 separate intervention sites in Western Sydney, Australia. Feasibility outcomes included recruitment, session attendance, and retention. The acceptability of the intervention was assessed through a process evaluation questionnaire completed post-intervention. Accelerometers and the short-form International Physical Activity Questionnaire were used to measure physical activity at baseline and post-intervention. Descriptive statistics were used for feasibility and acceptability outcomes, and changes in physical activity were examined using Wilcoxon signed-rank tests. Results: Of the 53 women who were contacted or expressed interest, 22 were eligible and enrolled in the study. Participants were primarily recruited through direct contact by Arab-Australian community workers and by word-of-mouth. Average session attendance was 63% and the retention rate post-intervention was 68%. The culturally-related intervention components, such as the appropriateness of content, and women-only setting, were rated highly favourably (4.33 to 4.87/5). General intervention elements, such as the face-to-face delivery, knowledge and approachability of facilitators, and session structure, were also rated favourably (4.33 to 4.93/5), and the lowest scored item was the intervention session frequency (3.2/5). There were no statistically significant changes in physical activity post-intervention. Conclusions: The findings from this study highlighted factors related to recruitment and delivery that need to be considered when developing physical activity interventions for Arab-Australian women. Further research is required using a larger sample and a randomised controlled trial design to examine the longer-term impact on physical activity, and to also examine ways of increasing intervention engagement and retention among Arab-Australian women

Unhealthy lifestyle behaviours and psychological distress : a longitudinal study of Australian adults aged 45 years and older

Individual associations between lifestyle behaviours and mental health have been established; however, evidence on the clustering of these behaviours and the subsequent impact on mental health is limited. The purpose of this study was to examine cross-sectional and longitudinal associations between combined unhealthy lifestyle behaviours (physical activity, sitting time, sleep duration, processed meat consumption, vegetable consumption, fruit consumption, smoking status, alcohol consumption) and the development of psychological distress (measured using the Kessler Psychological Distress Scale) in a large Australian sample. Participants were 163,707 Australian adults from the 45 and Up Study. Data from baseline (2006–2009) and follow-up wave 1 (2012) were analysed using binary logistic regression. The odds of reporting high or very high psychological distress at follow-up were significantly higher for those reporting five (AOR = 2.36; 95% CI 1.41–3.97, p = 0.001) or six or more (AOR = 3.04; 95% CI 1.62–5.69, p = 0.001) unhealthy lifestyle behaviours, in comparison to those reporting no unhealthy lifestyle behaviours at baseline. These findings suggest that a holistic, multi-faceted lifestyle approach addressing multiple behaviours may be required to support and promote positive mental health and to reduce the likelihood of psychological distress

Aging in Dense Colloids as Diffusion in the Logarithm of Time

The far-from-equilibrium dynamics of glassy systems share important phenomenological traits. A transition is generally observed from a time-homogeneous dynamical regime to an aging regime where physical changes occur intermittently and, on average, at a decreasing rate. It has been suggested that a global change of the independent time variable to its logarithm may render the aging dynamics homogeneous: for colloids, this entails diffusion but on a logarithmic time scale. Our novel analysis of experimental colloid data confirms that the mean square displacement grows linearly in time at low densities and shows that it grows linearly in the logarithm of time at high densities. Correspondingly, pairs of particles initially in close contact survive as pairs with a probability which decays exponentially in either time or its logarithm. The form of the Probability Density Function of the displacements shows that long-ranged spatial correlations are very long-lived in dense colloids. A phenomenological stochastic model is then introduced which relies on the growth and collapse of strongly correlated clusters ("dynamic heterogeneity"), and which reproduces the full spectrum of observed colloidal behaviors depending on the form assumed for the probability that a cluster collapses during a Monte Carlo update. In the limit where large clusters dominate, the collapse rate is ~1/t, implying a homogeneous, log-Poissonian process that qualitatively reproduces the experimental results for dense colloids. Finally an analytical toy-model is discussed to elucidate the strong dependence of the simulation results on the integrability (or lack thereof) of the cluster collapse probability function.Comment: 6 pages, extensively revised, final version; for related work, see http://www.physics.emory.edu/faculty/boettcher/ or http://www.fysik.sdu.dk/staff/staff-vip/pas-personal.htm

Random close packing of polydisperse hard spheres

We study jammed configurations of hard spheres as a function of compression speed using an event-driven molecular dynamics algorithm. We find that during the compression, the pressure follows closely the metastable liquid branch until the system gets arrested into a glass state as the relaxation time exceeds the compression speed. Further compression yields a jammed configuration that can be regarded as the infinite pressure configuration of that glass state. Consequently, we find that the density of jammed packings varies from 0.638 to 0.658 for polydisperse hard spheres and from 0.635 to 0.645 for pure hard spheres upon decreasing the compression rate. This demonstrates that the density at which the systems falls out of equilibrium determines the density at which the system jams at infinite pressure. In addition, we give accurate data for the jamming density as a function of compression rate and size polydispersity.Comment: Four pages, three figure

Laboratory Tests of Low Density Astrophysical Equations of State

Clustering in low density nuclear matter has been investigated using the NIMROD multi-detector at Texas A&M University. Thermal coalescence modes were employed to extract densities, $\rho$, and temperatures, $T$, for evolving systems formed in collisions of 47 $A$ MeV $^{40}$Ar + $^{112}$Sn,$^{124}$Sn and $^{64}$Zn + $^{112}$Sn, $^{124}$Sn. The yields of $d$, $t$, $^{3}$He, and $^{4}$He have been determined at $\rho$ = 0.002 to 0.032 nucleons/fm$^{3}$ and $T$= 5 to 10 MeV. The experimentally derived equilibrium constants for $\alpha$ particle production are compared with those predicted by a number of astrophysical equations of state. The data provide important new constraints on the model calculations.Comment: 5 pages, 3 figure

Effectiveness of adult health promotion initiatives delivered through professional sport : systematic review and meta-analysis

Background: Researchers are capitalising on the strong connections that sport fans have with their teams for health promotion programmes, yet no existing systematic reviews have evaluated the effectiveness of interventions delivered through professional sport. Objective: The aim of this study was to systematically collate, evaluate, and synthesise the evidence on health promotion interventions implemented in professional sport settings. Methods: Randomised controlled trials reporting on adult health promotion initiatives delivered in professional sport settings were identified through electronic database searches in CINAHL, MEDLINE, SPORTDiscus, Scopus, the Cochrane Central Register of Controlled Trials (CENTRAL), and Google Scholar. Data on health-related outcomes (e.g., weight, physical activity, dietary intake) were extracted and synthesised, and random effects meta-analyses were conducted to examine effects for weight and waist circumference. Risk of bias was examined using the Cochrane risk-of-bias tool for randomised controlled trials (RoB 2). Results: Six studies reporting on five unique interventions met the inclusion criteria, and all included studies were gender sensitised and exclusively targeted men. Intervention effects were observed for several health outcomes, including physical activity, dietary intake, and psychosocial health. All studies aimed to reduce weight, and for most studies (n = 4), weight was a primary outcome, either of the included study or to inform a future definitive trial. Findings from the meta-analysis revealed an overall significant difference in change in weight of − 3.2 kg (95% confidence interval [CI] − 4.6 to − 1.8) and waist circumference of − 3.9 cm (95% CI − 4.9 to − 2.8), both in favour of the intervention group at 12 weeks. Intervention effects were also reported for several other health outcomes (e.g., physical activity, dietary intake, psychosocial health); however, they were not consistently measured across the studies and thus were not meta-analysed. Conclusion: Health promotion interventions delivered through professional sporting organisations can significantly improve weight- and lifestyle-related health outcomes. Representation across the socioeconomic spectrum and across culturally and linguistically diverse groups was limited. As only a limited number of studies met the inclusion criteria for this review, a need exists for rigorously designed interventions, standardised intervention approaches, with long-term follow-up, and the potential for scalability

Experimental Determination of In-Medium Cluster Binding Energies and Mott Points in Nuclear Matter

In medium binding energies and Mott points for $d$, $t$, $^3$He and $\alpha$ clusters in low density nuclear matter have been determined at specific combinations of temperature and density in low density nuclear matter produced in collisions of 47$A$ MeV $^{40}$Ar and $^{64}$Zn projectiles with $^{112}$Sn and $^{124}$Sn target nuclei. The experimentally derived values of the in medium modified binding energies are in good agreement with recent theoretical predictions based upon the implementation of Pauli blocking effects in a quantum statistical approach.Comment: 5 pages, 3 figure

The power of PISA – limitations and possibilities for educational research

On 6th December 2016, the Programme for International Student Assessment (PISA) releases its report on the achievements of 15-year-olds from 72 countries and economies around the world. This triennial international survey aims to evaluate education systems across 72 contexts by testing skills in Mathematics, Science and Reading Literacy. This is the sixth cycle of PISA and the OECD suggests countries and economies now have the capability to compare the results over time to ‘assess the impact of education policy decisions’ . Compared to other education studies, the media coverage of PISA must be described as massive (Meyer and Benavot, 2013, Baird et al., 2016) and, as with previous years, it is expected that PISA will attract considerable discussion among policy makers, educators and researchers (Wiseman, 2014). It is therefore timely to present a thematic issue of Assessment in Education, where we publish four articles that have analysed previous datasets from the PISA studies each commenting upon the challenges, limitations and potential future assessment research on the PISA data. The articles touch upon issues regarding sampling, language, item difficulty and demands, as well as the secondary analyses of students’ reported experiences of formative assessment in the classroom. One important message from the authors in this thematic Special Issue is the need for a more complex discussion around the use and misuse of PISA data, and the importance of pointing to the limitations of how the results are presented to policy makers and the public. In an area where the media produces narratives on schools and education systems based upon rankings in PISA, researchers in the field of large-scale assessment studies have a particularly important role in stepping up and advising on how to interpret and understand these studies, while warning against potential misuse. </p

Experimental and Numerical Investigation of the Use of Ultrasonic Waves to Assist Laser Welding

Data Availability Statement: Data are contained within the article.This study evaluates the enhancement of laser welding using ultrasonic waves aimed at reorganising the intermetallic position in such a fashion that leads to increased mechanical properties of welds in battery pack assemblies for electric vehicles. The experiment employed 20 kHz and 40 kHz High-Power Ultrasound Transducers (HPUTs) in both contact and contactless modes. A simplified experimental configuration is suggested to represent conditions similar to those found in electric vehicle battery pack assemblies. Measurements of vibration transmission to aluminium alloy 1050 plates revealed more than a 1000-fold increase in acceleration amplitude in contact mode compared to contactless mode. The 20 kHz transducer in contactless mode demonstrated superior performance, showing a 10% increase in load and 27% increase in extension compared to welding without ultrasonic assistance. On the other hand, the 40 kHz transducer, while still improved over non-ultrasonic methods, showed less pronounced benefits. This suggests that lower-frequency ultrasonic assistance (20 kHz) is more effective in this specific context. The study explores ultrasonic assistance in laser welding copper (Cu101) to aluminium alloy 1050 using 20 kHz and 40 kHz HPUTs, showing that both transducers enhance microstructural integrity by reducing copper homogenisation into aluminium, with the 20 kHz frequency proving more effective in this context. A numerical simulation was conducted to evaluate the transmission of pressure into the molten pool of the weld, correlated with the vibration results obtained from the 20 kHz transducer. The numerical simulation confirms that no cavitation is initiated in the molten pool area, and all improvements are solely due to the ultrasonic waves.This research was funded by Innovate UK, grant number: 10018077. The APC was funded by Brunel University London