bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and off-design analysis of a Tesla Turbine utilizing CO2 as working fluid
Authors: Fiaschi Daniele , Talluri Lorenzo
Published: August 2019

The Tesla turbine is a bladeless expander; which principle of operation is based on the conversion of the viscous forces, developed by the flow while expanding through the rotor, in mechanical energy. It is especially suitable for small/micro size distributed energy systems (kW scale), mainly due to its very low cost, which results from the simple structure of the machine.

The Tesla turbine works well at relatively moderate expansion ratios. Therefore, it is fit for CO2 power cycles applications that are characterised by small expansion ratio, despite the high pressure involved. In this work, the design and off-design analysis of a Tesla turbine for small/micro power application utilizing CO2 cycles is proposed.

The optimized design was targeted for an inlet temperature of 150 °C and an inlet pressure of 220 bar. The final optimized geometry of the expander was defined, achieving a 23.4 W per channel power output with a 63% isentropic efficiency, when working with a 10.1 bar pressure drop at 2000 rpm. Furthermore, the turbine placement on the Baljè diagram was performed in order to understand the direct competitors of this machine.

Finally, starting from the design configuration, the maps of efficiency at variable load and flow coefficients and that of reduced mass flowrate at variable pressure ratio were realized. Through the merging of these curves, the off-design maps of the Tesla turbine were obtained, highlighting a very limited sensitivity of the efficiency to variable working conditions, if rotational speed is adequately adjusted.
Market opportunities for small energy harvesters
Authors: Cuneo Alessandra , Barberis Stefano , Traverso Alberto , Silvestri Paolo
Published: August 2019

There are several small energy sources that can be exploited to provide useful energy: small temperature differences, mechanical vibrations, flow variations, latent exhausts are just some examples. The recovery of such common and small energy sources, usually wasted, for example with the conversion into useful amounts of electrical energy, is called energy harvesting. Energy harvesting allows low-power embedded devices to be powered from naturally-occurring or unwanted environmental energy (e.g. pressure or temperature difference). The main aim in the last years of researches in such field, was the increasing of the efficiency of such components, with a higher power output and a smaller size. At present, a wide range of systems incorporating energy harvesters are now available commercially, all of them specific to certain types of energy source. Energy harvesting from dissipation processes such as fluid lamination is a challenge for many different applications. In addition, control valves to dissipate overpressures are common usage of many plants and systems. This paper surveys the market opportunities of such harvesting systems, considering the trade-offs affecting their efficiency, their applicability, and ease of deployment. Particular attention will be devoted to small energy harvesters than can exploit small expansions, such as from lamination valves or to systems that can feed mini sensors from small pressure drops, promising compactness, efficiency and cost effectiveness.
Techno-economic analysis for the assessment of heat pump integration in a real poly-generative energy district
Authors: Barberis Stefano , Robello Paola , Rattazzi Diego , Rivarolo Massimo , Bellotti Daria , Magistri Loredana
Published: August 2019

The present research study aims at analysing technical and economic feasible solutions for heat pumps integration in energy districts for polygeneration purpose and particularly to store excess of electricity via Power-to-heat schemes considering that, from previous researchers’ works, thermal storage has been identified as the most remunerative and easy to handle storage technology to maximise self-consumption in polygeneration grids. This technology is already developed and currently employed for conditioning of residential, commercial and industrial buildings. However, studies regarding the analysis of heat pumps’ integration in energy districts for distributed generation are still limited. The potential advantages of its employment in this context are fuel savings, a lower emission level and the possibility to couple it with local renewable energy sources (i.e. solar panels, wind turbines) and traditional generators (i.e. engines, micro gas turbines) in order to increase flexibility in operational terms. In this paper, a performance analysis of the poly-generation energy district installed at the University of Genoa Campus, located in Savona, is analysed throughout a whole year: the model is implemented using a dedicated software tool, developed by Thermochemical Power Group. Different solutions for the integration of the heat pump, including size optimization, are investigated, considering the real data related to the University of Genoa Campus: the final aim of the analysis is to determinate the best operational strategy, minimizing variable costs (i.e. fuel) and evaluating the economic feasibility of heat pump installation in the energy district. This work has been also redacted as a preliminary analysis for solar-coupled HP integration (from a optimized management point of view) to be performed in the demonstration campaign of H2020 ENVISION Project*, where both RINA Consulting and University of Genova collaborate.
SHIP2FAIR – Martini & Rossi: integration of Solar Heat in Industrial Process – Preliminary evaluation
Authors: Barberis Stefano , Peccianti Francesco , Castellino Luca , Bolognesi Thomas , Bortoletto Alessandro
Published: August 2019

SHIP2FAIR is a H2020 European funded project†, which aim to foster the integration of solar heat in industrial processes from the agro-food sector facilitating the integration of solar heat production in low temperature processes. Based on the assessment of the industrial process for the production of different spirits and the local solar potential in Pessione plant (TO) of Martini & Rossi – one of the four demosite of the project -, the preliminary results that guided the choice of the most suitable solar collectors (Fresnel) and the definition of the thermo-economic parameters for the solar plant are hereby presented. The preliminary assessment takes into account different perspectives from the industrial and economic point of view: the availability of suitable surfaces, the economics of the investment and the best processes to be fed by solar produced steam towards a preliminary techno-economic feasibility study. The starting points for the analysis have been the characterization of the thermal demand in terms of necessary temperature level (°C), overall consumption and time distribution. The following step has been the identification of the suitable collectors to be installed taking into account the thermal parameters presented before, the boundary conditions of the industrial facility (e.g. space available, orientation, etc.), the technical characteristics of the collector itself and the solar irradiation available considering the plant’s location. Moreover, the complex thermal facility in the factory, constituted by multiple (3) gas boilers and a Combined Heat and Power (CHP) plant in two different but linked pressurized steam loops, is taken into account for the definition of the solar collectors configuration and their integration via the proper management of heat generators and storage. The calculations are based on the expected thermal (steam) production guaranteed by the solar collectors and avoided GHG based on the reduction of gas fired boilers consumption.
Techno-economic analysis of multipurpose OTEC power plants
Authors: Barberis Stefano , Giugno Andrea , Sorzana Giacomo , Lopes Miguel F.P. , Traverso Alberto
Published: August 2019

Ocean Thermal Energy Conversion (OTEC) is a promising technology to provide sustainable and dispatchable energy supply to oceanic coastal areas and islands. It exploits the temperature difference between deep cold ocean water and warm tropical surface water in an Organic RankineCycle (ORC), guaranteeing a continuous and dispatchable electric production, overcoming one ofthe most critical issue of renewable generators such as PV or wind turbines. Despite the technological maturity of ORC application to OTEC systems, it still presents technical and economicbarriers mainly related to their economic feasibility, large initial investments as well as heavy and time demanding civil installation works. To overcome such issues, multipurpose OTEC plants are proposed, producing electrical power as well as other products, such as useful thermal power (e.g. ambient cooling) and desalinated water. Since OTEC engineering is still at a lowdegree of maturity, there are no widespread and established tools to facilitate OTEC feasibility studies and to allow performance and cost optimization. Therefore, in this paper, a new tool for techno-economic analysis and optimization of multipurpose OTEC plants is presented. Starting from a detailed database of local water temperature and depth, the approach allows to provide a quantitative insight on the achievable performance, required investment, and expected economic returns, allowing for a preliminary but robust assessment of site potential as well as plant size. After the description of the techno-economic approach and related performance and cost functions, the tool is applied to an OTEC power plant case study in the range of 1 MW gross electrical power, including a preliminary assessment of scaling-up effects.
Tiny Tesla Turbine Analytical Performance Validation Via Dynamic Dynamometry
Authors: Traum Matthew J. , Weiss Hope L.
Published: August 2019

Tesla turbines produce power at high rotation rate and low torque relative to other prime movers. At a tiny scale, this attribute renders Tesla turbines poorly matched to dynamometers designed to characterize electricand gasoline-powered radio-controlled vehicles and kit cars. Techniques are needed to enable Tesla turbine design and performance evaluation. An analytical modelling approach was recently developed by Carey, and a complimentary experimental technique, dynamic dynamometry, can determine Tesla turbine power curves without a dynamometer. This paper mutually validates these approaches by comparing them to each other using results from a 3D printed 4-disk tiny Tesla turbine with characteristic disk inner/outer diameter of 11.54 ± 0.01 mm and 24.85 ± 0.01 mm respectively. The Carey model predicts maximum power output of 0.077 ± 0.015 W, and dynamic dynamometry predicts 0.122 ± 0.008 W, a 36.9% difference. Bounding assumptions were used and more accurate parameter measurements will drive these values closer together. Peculiarities of tiny Tesla turbine operation are also described, including the discovery that turbine spin-down rotational velocity is not linear with time. This phenomenon is likely caused by fluid boundary layer shear between the housing and outer disks. It is not observed in larger Tesla turbines, suggesting a speed, size and/or disk count threshold at which this phenomenon introduces non-trivial parasitic reduction in performance.
Context-Based chemistry teaching: Its impacts on science expectations of pre-service teachers
Authors: Altundağ Canan Koçak
Published: August 2019

The purpose of this study was to investigate pre-service teachers' science expectations on learning science after they completed introductory Context-Based teaching. The sampling of the study consisted of 21 pre-service teachers studying at Hacettepe University, Faculty of Education. This is a two-dimensional research study where qualitative and quantitative research methods are used together. The scores obtained by participating groups from the “Science Expectations Questionnaire”. Additionally, pre-service teachers' interviews are given as evidences. As a result of the evaluation of pre-service teachers' the expectations about learning science on independence, coherence, concept, reality link, math link, and effort dimensions, it is thought that there will be important outcomes in terms of improvement of the quality of teacher training at the university and that there will be an important contribution to literature in this sense.
The restoration of the wooden monument church Saint Parascheva from Crivina de Sus, a training for the interdisciplinary project team
Authors: Obradovici Vladimir
Published: August 2019

The restoration project of Saint Parascheva wood monument church, started in 2013 in Crivina de Sus village, from another project initiated by the association AsoP, to study the cultural landscape of the Faget Area, where the oldest wooden monument church in the Bant region in Romania is located. Studies commenced in 2013 have shown us that the wooden church is the central element of the landscape while at the same time being in a precarious state of preservation. In the next years, experimental studies on the monument and it's context, realised by specialists and students from areas related to restoration, followed. These investigations have initiated a restoration school that formed an interdisciplinary team for studying and planning restorations of the wooden churches in our region. In the summer of 2018, the actual restoration of the church began, which is also a learning project for the team of restorers and volunteers.
Design skills assessment in teaching 3D modeling
Authors: Lokalov Vladimir , Klimov Igor
Published: August 2019

The article discusses the design skills assessment method, which was developed and used to teach basics of three-dimensional modeling. This method is necessary because the creation of a virtual 3D model usually does not include the design phase as a separate phase with own specifications and design documentation and all design activities are performed in mind without any preliminary sketches. The offered method allows assessing the quality of the student's mental design operations based on the analysis of the 3D modeling process tracking. The student's activity in the 3D modeling environment was captured using special software. The obtained data allow to identify the essential parameters of the students' actions (correctness, optimality, etc.), which were used to quantify their design skills. The construct validity of the proposed method and its statistical significance of the assessment were confirmed.
Relations between preservice teachers' views about nature of science and sense of efficacy
Authors: Şen Şenol
Published: August 2019

The purpose of this study was to investigate the relations between preservice teachers' views about nature of science and sense of efficacy. The study group was comprised of 72 female and 24 male preservice teachers and their average age were 19.53 (range 18 to 35), and 20.75 (range 18 to 52), respectively. The Nature of Science View Scale (NOSvs) and the Teachers' Sense of Efficacy Scale (TSES) were used as data collection tools. The Pearson product-moment correlation analysis was conducted to explore the relations between pre-service teachers' views about nature of science and sense of efficacy. According to the correlation analysis, it was determined that there is a significant correlation between preservice teachers' views about nature of science (p=.000 and r=.403, for the total score) and sense of efficacy.
The development of coeducation in Poland against European backdrop (19th-21st century)
Authors: Dormus Katarzyna
Published: August 2019

The goal of the paper is to shed light on the problem of coeducation on a Poland in the European backdrop in 19th-21st century. An excellent source for the analysis of this topic is, in particular, the 19th- and 20th- century pedagogical and female press, documents of educational authorities, school reports. Results and conclusion: During the late 19th and early 20th century, coeducation was − in all of Europe − a source of controversy, resulting in a public discussion. The first coeducational secondary schools in the Polish territories were established over the course of the First World War. Coeducation was widely adopted after the Second World War, but the question of whether coeducation brings more benefits or drawbacks remains open for debate.
An exploratory study examining 10th-grade students' conceptions about mountain building and relief
Authors: Vélez-Felipe Ana María , Vázquez-Vílchez Mercedes , Salmerón-Vílchez Purificación , García-Yeguas Araceli , Carrillo-Rosua Javier
Published: August 2019

Mountain building is a subject that has not been thoroughly explored in relation to misconception research. However, mountain building is complex, involving not only endogenous processes, but also exogenous ones. The main objective of this contribution is to determine, from a holistic standpoint, the misconceptions that students hold concerning mountain building. We have designed and used a questionnaire posing three kinds of questions to students related to their: geological knowledge, emotional issues, and academic background. The main benefit offered by the present research is the identification of misconceptions not covered in the literature available. We have found that the most common misconception is that the mountains occurs only at the edge of convergent lithospheric plates and is less frequent at divergent edges. Some students related the edge of the plates to areas under the sea or on the coast.
Improving the physics problem solving and problem posing skills of prospective physics teachers
Authors: Çıldır Sema
Published: August 2019

This study was conducted with the aim of providing awareness and skill to the prospective physics teachers in the areas problem posing and problem solving. In this study, which was carried out according to qualitative research methods, information was given about problem building and solving approaches, and then the process of transforming this knowledge into skills was examined. To this end, the prospective teachers were asked to solve at least two physics problems according to the Polya's problem solving steps and explain each step they applied in detail. In the same manner, they were asked to pose at least two physics problems and solve their own problems according to the Polya's problem solving steps in the problem posing stage. The process was continued through semistructured interviews and the opinions and suggestions of the prospective teachers were obtained at the end of the study. As a result of the study, it was determined that prospective teachers had difficulty in problem posing and they preferred to pose free problems, in the problem solving, they did not use techniques such as drawing, graphing etc. in the identification step of a problem, some prospective teachers could not perform the evaluation stage and these results were discussed with the prospective teachers. It was concluded that the prospective teachers wanted to use their problem posing and solving skills in their professional lives in order to reinforce the subject and to increase the motivation. In order to improve the creative problem solving and critical thinking skills of the prospective teachers, it is suggested that problem posing and solving skills should be included more in the curriculum.
Investigating the pre-service science teachers' conceptions about scientific inquiry research
Authors: Hamed Soraya
Published: August 2019

The following study presents the analysis of the conceptions of 40 future teachers when they are presented with a practical case related to the thermal properties of materials. This case is proposed as an experimental activity in which students must develop and reflect on the strategies of scientific research processes. For this, they are induced to explain: 1. The hypothesis from which they start to respond to the predetermined problem, 2. The experimental design to address it, 3. The results and 4. The conclusions obtained. The results indicate the existence of two tendencies, a majority related to a common sense thinking and another more counter-intuitive and scientific to explain natural phenomena.
Quels sont les profils motivationnels envers l’activité physique et la sédentarité de patients admis en réhabilitation respiratoire ?
Authors: Chevance Guillaume , Roux Mélissa , Calvat Amandine , Oliver Nicolas , Alexandre François , Héraud Nelly , Boiché Julie
Published: August 2019

Contexte : La poursuite d’une Activité physique (AP) régulière et la limitation des comportements sédentaires (SED) représentent des enjeux fondamentaux de la réhabilitation respiratoire (RR). La motivation joue un rôle significatif à cet égard et peut évoluer au cours d’un programme. Cette étude avait pour objectif d’identifier les profils motivationnels présents au début d’un programme de RR. Méthode : Quatre variables motivationnelles (attitudes, auto-efficacité, intentions, planification) ont été évaluées au début d’un programme de RR grâce à un questionnaire auprès de 211 participants. Ces variables ont ensuite fait l’objet d’analyses de profils latents. Résultats : Concernant la motivation envers l’AP, 3 profils sont apparus : un profil de patients « Motivés » (66 %), un profil de patients « Non motivés » (20 %) et un profil de patients présentant une « Faible planification » (14 %). Concernant la SED, 3 profils sont apparus : un profil « Motivés » (82 %), un profil « Faibles intentions » (10 %) et un profil « Faible confiance » (8 %). Aucune caractéristique démographique, clinique, ou comportementale ne distinguait ces profils, à l’exception de la sévérité de la pathologie respiratoire. Conclusion : Les patients admis pour un programme de RR présentent des profils motivationnels variés et leurs profils envers l’AP et la SED ne sont pas nécessairement associés. Identifier ces profils pourrait permettre une meilleure individualisation des interventions vers un style de vie actif, en s’appuyant sur des taxonomies récentes.
Wege zu einem herzlichen Nein
Authors: Perske Heike
Published: August 2019

Nein zu sagen, ist wichtig, um sich abzugrenzen. Oft fällt es jedoch im Alltag schwer. Ursachen hierfür reichen von Angst vor Ablehnung bis zu familiären Prägungen. Verschiedene Übungen und Mittel können dabei helfen, sich äußerlich und innerlich abzugrenzen.
Muss ich als Heilpraktiker eine Leitungswasserüberprüfung nachweisen?
Authors: Kämper Siegfried
Published: August 2019

Eine Kollegenfrage zum Thema Leitungswasserüberprüfung in der Heilpraktikerpraxis.
Human Papilloma Virus Infection and Anal Squamous Intraepithelial Lesions
Authors: Svidler López Laura , La Rosa Luciana
Published: August 2019

This article addresses the natural history of the human papilloma virus (HPV) infection to anal squamous intraepithelial lesions, and onto squamous cell carcinoma of the anus. This article provides overviews of the virology, pathophysiology, nomenclature, classification, historical terms, risk factors, clinical evaluation, differential diagnosis, and treatment of HPV infection and its sequelae.
Direct Synthesis of Nitrones via Transition-Metal-Free Ring-Opening of N-Tosylaziridines with the Nitrogen Atom of Various (E)-Aldoximes and (E)-Ketoximes
Authors: Li Xing , Yan Wenjing , Zhang Rui , Chang Honghong , Gao Wenchao , Tian Xiuping , Wei Wenlong
Published: August 2019

The KOH-, K2CO3-, or Et3N-catalyzed ring-opening reaction of N-tosylaziridines using the nitrogen atom of a series of (E)-aldoximes and (E)-ketoximes as a nucleophilic atom instead of an oxygen atom was developed to construct various nitrones under mild reaction conditions. Diverse (E)-aldoximes and (E)-ketoximes were demonstrated to be compatible with this reaction and the products of O-ring-opening reactions were not detected for most examples.
Relationship of Platelet Reactivity and Inflammatory Markers to Recurrent Adverse Events in Patients with ST-Elevation Myocardial Infarction
Authors: Adatia Krishma , Farag Mohamed F. , Gue Ying X. , Srinivasan Manivannan , Gorog Diana A.
Published: August 2019

Background Patients with ST-elevation myocardial infarction (STEMI) exhibit pro-thrombotic and pro-inflammatory states. Markers of enhanced platelet reactivity and inflammation are predictive of adverse outcome. However, the relationship between these biomarkers, and their combined usefulness for risk stratification, is not clear.

Methods In a prospective study of 541 patients presenting with STEMI, blood samples were taken on arrival to measure high-sensitivity C-reactive protein (hs-CRP), neutrophil/lymphocyte ratio (NLR) and platelet reactivity using the point-of-care Global Thrombosis Test. These biomarkers, alone and in combination, were related to the occurrence of major adverse cardiovascular events (MACE, defined as composite of cardiovascular death, myocardial infarction and cerebrovascular accident) at 30 days and 12 months.

Results Platelet reactivity and hs-CRP, but not NLR, were weakly predictive of MACE at 30 days and 12 months. The combination of enhanced platelet reactivity and raised hs-CRP was strongly predictive of MACE at 30 days (hazard ratio [HR] 3.46 [95% confidence interval [CI] 1.81–6.62], p < 0.001) and 12 months (HR 3.46 [95% CI 1.81–6.63], p < 0.001). Combination of all three biomarkers (NLR, hs-CRP and platelet reactivity) provided the best prediction of MACE at 30 days (HR 3.73 [95% CI 1.69–8.27], p < 0.001) and 12 months (HR 3.85 [95% CI 1.72–8.60], p < 0.001), and improved the prediction of MACE when added to Thrombolysis In Myocardial Infarction score (net reclassification index 0.296, p < 0.001).

Conclusion A combination of three easy to measure biomarkers on arrival, namely hs-CRP, NLR and platelet reactivity, can help identify STEMI patients at high risk of recurrent adverse events over the subsequent year.
Low-voltage inverted organic light-emitting diodes with double-layer election injection layer based on silicon dioxide
Authors: Ding Lei , Wang Jiang-Nan , Ni Ting , Zhang Fang-Hui
Published: August 2019

We demonstrated low operating voltage and highly efficient inverted bottom-emission organic light-emitting diodes using SiO2/n-doped 4,7-diphenyl-1,10-phenanthroline (Bphen) as an electron injection layer (EIL) at the interface between the indium tin oxide (ITO) cathode and the organic electron transport layer. The current and power efficiencies exceed 79.2 cd A−1 and 67.8 lm W−1 at 3.6 V. The ultraviolet photoelectron spectroscopy measurement showed that the insertion of the SiO2 layer reduced the electron injection barrier between ITO and Li doped Bphen. Based on the energy levels and the current-voltage characteristics of electron-dominated devices, we demonstrate that the interface between ITO and the n-doped electron transporting layer (ETL) is important for efficient electron injection into ETL.
Phase field simulation of spinodal decomposition in Zr–Nb alloys for implant materials
Authors: Wang Y. H. , Zhang D. C. , Pi Z. P. , Lin J. G. , Wen Cuie
Published: August 2019

Zirconium (Zr)-based alloys, a new class of hard-tissue replacement materials, show lower strength compared to traditional medical metal materials such as stainless steel, cobalt alloy, and Ti-6Al-4V alloys, which may lead to premature fracture of the implant. Spinodal decomposition can increase the strength greatly without an increase in the elastic modulus of the alloy. In this study, a phase field method based on the Cahn–Hilliard equation was applied to the simulation of the spinodal decomposition in Zr–Nb alloys. The spinodal region on the Zr–Nb phase diagram was calculated by the phase field method by considering the interfacial energy and elastic strain energy contribution to the total Gibbs free energy. Furthermore, the effects of the Nb content and heat-treatment temperature on the morphology, amplitude, and volume fraction of the decomposition phases are discussed. Simulation results indicate that the morphology of the β′ phase is interconnected and regular with a preferential alignment in the ⟨110⟩ direction to reduce the strain energy, which may restrict the spinodal decomposition of the alloys. The two droplet phases merge, which can be attributed to the reduction in the elastic strain energy. The phase decomposition rate increases with an increase in aging temperature, but the aging temperature has only a small influence on the final volume fraction of the β′ phase.
Photoluminescence properties as a function of growth mechanism for GaSb/GaAs quantum dots grown on Ge substrates
Authors: Zon  , Thainoi Supachok , Kiravittaya Suwit , Tandaechanurat Aniwat , Kanjanachuchai Songphol , Ratanathammaphan Somchai , Panyakeow Somsak , Ota Yasutomo , Iwamoto Satoshi , Arakawa Yasuhiko
Published: August 2019

In this work, we use photoluminescence (PL) spectroscopy to investigate how self-assembled GaSb/GaAs quantum dots (QDs) depend on their growth mechanism. Carrier transfer (i.e., carrier recombination in QDs and escape through the barrier layer) is investigated as a function of excitation-power- and temperature-dependent PL measurements. A drastic blueshift of the QD peak energy from 1.23 to 1.30 eV and a further shift to 1.33 eV reveal the influence of the GaSb growth rate and the growth temperature on the optical properties of these QDs. The thermal activation energy is extracted from the temperature-dependent PL by fitting the integrated PL intensity of the QD peaks to the Arrhenius relation. The QDs grown at the growth rate of 0.1 monolayers/s at 450 °C have higher thermal activation energy (109 meV) than those grown at a lower growth rate and higher QD growth temperature. The observed PL characteristics are discussed in terms of QD size, uniformity of QDs, and material intermixing occurring during QD growth on the buffer layer and capping layer.
A compact, ultra-high vacuum ion source for isotopically enriching and depositing 28Si thin films
Authors: Tang K. , Kim H. S. , Ramanayaka A. N. R. , Simons D. S. , Pomeroy J. M.
Published: August 2019

An ultrahigh vacuum (UHV) compatible Penning ion source for growing pure, highly enriched 28Si epitaxial thin films is presented. Enriched 28Si is a critical material for quantum information due to the elimination of nuclear spins. In some cases, the material must be grown by low temperature molecular beam epitaxy, e.g., scanning tunneling microscopy hydrogen lithography-based devices. Traditional high-purity physical vapor methods typically deliver a very small fraction of source material onto the target substrate, making the cost for use with highly enriched source materials very high. Thus, directed beam sources provide an efficient alternative. This UHV Penning source uses all metal or ceramic parts and a removable electromagnet to allow bake-out. The source gas is a commercial (natural isotope abundance) silane gas (SiH4), an inexpensive source material. High enrichment levels up to 99.999 87% (8.32 × 10−7 mol/mol 29Si) and high chemical purity of 99.965% are shown without postprocessing. We present and discuss the discharge properties of this new source, the ion mass spectrum when coupled to our mass filter, and the secondary ion mass spectroscopy of the grown films.
Bi2Te3 photoconductive detector under weak light
Authors: Kang Ting-Ting , Chen Ping-Ping
Published: August 2019

Bi2Te3 − xSex photoconductive detectors are attractive due to their linear photo-response (LPR), potential in ultrabroadband photo-detection, and compatibility with CMOS technology. However, as a fundamental issue for photo-detectors, the weak-light photo-response of Bi2Te3 − xSex detectors was covered by the bolometric response, the photo-thermoelectric effect, and the 300 K background black-body radiation from the optical window. Here, using a window-less system, we systematically measure the weak-light photo-response of a Bi2Te3 photoconductive detector. The bolometric response and photo-thermoelectric effect are carefully excluded. It shows that LPR can persist to a small light power density of P < 10−8 W/cm2. Meanwhile, the response is maximized at ∼80 K temperature. We suggest that the LPR is rooted in the unique carrier recombination configuration of Bi2Te3, which can result in a constant lifetime for light-generated carriers. The concerned trap level is manifested by a negative photo-response under reduced light intensity. The signature of surface state related signal is presented as a photo-response with the maximum at ∼10 K temperature, which is fragile under increased light intensity. Although the window-less photo-response measurement is at its early stage, it provides a perspective which is different from that of the traditional optical-window based measurement.
A room-temperature ion trapping apparatus with hydrogen partial pressure below 10−11 mbar
Authors: Obšil P. , Lešundák A. , Pham T. , Lakhmanskiy K. , Podhora L. , Oral M. , Číp O. , Slodička L.
Published: August 2019

The lifetime of trapped ion ensembles corresponds to a crucial parameter determining the potential scalability of their prospective applications and is often limited by the achievable vacuum level in the apparatus. We report on the realization of a room-temperature 40Ca+ ion trapping vacuum apparatus with unprecedentedly low reaction rates of ions with a dominant vacuum contaminant: hydrogen. We present our trap assembly procedures and hydrogen pressure characterization by analysis of the CaH+ molecule formation rate.
Metal plate deformation under magnetic field pulse of complex shape
Authors: Kudasov Yu. B. , Surdin O. M. , Platonov V. V. , Kozabaranov R. V. , Maslov D. A. , Makarov I. V. , Svetlov A. S. , Popov E. Ya.
Published: August 2019

A dynamic deformation of sheet magnetic and nonmagnetic metal workpieces under a combination of a slowly varying primary magnetic field and a sequence of short magnetic field pulses with the opposite polarity is studied. This regime corresponds to backward electromagnetic forming. A fast motion of the workpiece induces an additional electromotive force in a discharge circuit and substantially alters a shape of the current pulse in an inductor. During the short opposite pulses, the Lorentz and magnetization components of the magnetic pressure on the magnetic workpiece demonstrate an unusual behavior, that is, the Lorentz pressure is attractive and the magnetization one is predominantly repulsive relative to the inductor. This phenomenon is discussed in terms of a two-dimensional axisymmetric problem.
Relativistic theory of electron-nucleus-radiation coupled dynamics in molecules: Wavepacket approach
Authors: Hanasaki Kota , Takatsuka Kazuo
Published: August 2019

We propose a general theoretical scheme of relativistic electron-nucleus coupled dynamics of molecules in radiation fields, which is derived from quantum electrodynamical formalism. Aiming at applications to field-induced dynamics in ultrastrong laser pulses to the magnitude of 1016 W/cm2 or even larger, we derive a nonperturbative formulation of relativistic dynamics using the Tamm-Dancoff expansion scheme, which results in, within the lowest order expansion, a time-dependent Schrödinger equation with the Coulombic and retarded transversal photon-exchange interactions. We also discuss a wavepacket type nuclear dynamics adapted for such dynamics.
NEXAFS spectra and specific dissociation of oligo-peptide model molecules
Authors: Chiang Yu-Ju , Huang Wan-Chou , Ni Chi-Kung , Liu Chen-Lin , Tsai Cheng-Cheng , Hu Wei-Ping
Published: August 2019

Total-ion-yield near-edge X-ray absorption fine-structure (NEXAFS) spectra of three oligo-peptide model molecules were recorded. The NEXAFS spectra were also calculated with time-dependent density functional theory; the calculated spectra are consistent with the experimental measurements. The ionic products from core-excited molecules and their branching ratios as functions of excitation energy show branching ratios 42%-75% of dissociation of the peptide bond, especially at resonant excitations. The major destination orbitals assigned at these excitation energies show significant antibonding character along peptide bonds, which causes large probabilities of bond cleavage.
CONOPT solver embedded in GAMS for optimal power flow
Authors: Ćalasan Martin P. , Nikitović Lazar , Mujović Saša
Published: August 2019

This paper addresses the optimal power flow (OPF) issue by using the CONOPT solver for nonlinear programming embedded in the Generalized Algebraic Modeling System (GAMS) software package. The research is performed on both standard IEEE 30-bus test systems and their modified version. The system modification has been done in order to assess the impact of the integrated renewable energy sources, primarily wind energy sources, on the OPF. The obtained results strongly confirm the GAMS/CONOPT efficiency for solving the OPF problem. GAMS/CONOPT always converges to the same optimal solution contrary to many well-known optimization techniques. Additionally, the GAMS/CONOPT requested computation time considerably outperforms that of the other techniques in the field (in all analyzed cases, in the worst situation, more than 30 times). These performances promote GAMS/CONOPT as a very successive tool for solving the real-time OPF problem.
A data-driven approach to construct a quantitative relationship between microstructural features of fatigue cracks and contact acoustic nonlinearity
Authors: Jin Jiang , Shokouhi Parisa
Published: August 2019

This study demonstrates the feasibility of a data-driven approach to construct a quantitative relationship between nonlinear acoustic parameters and microstructural features of contact interfaces. The near-surface nonlinearity is measured using dynamic acousto-elastic testing (DAET) with a surface wave probe, while the microstructural features are extracted from scanning electron microscopy (SEM) images of fatigue cracks. Four aluminum alloy samples, each having a fatigue crack are prepared. Six local nonlinearity parameters are measured at different locations along the crack propagation direction. A total of 40 local measurements are acquired. A principal component analysis (PCA) reveals that all six nonlinearity parameters are correlated and hence can be replaced by one principal component (PC). Fifteen crack micro-geometrical features at each measurement point were extracted from the SEM images. Regression analysis is used to relate the PC of the nonlinearity parameters to the microstructural features at the crack interface. We compare three regression models that take variable selection into account: stepwise multiple linear regression (MLR), stepwise principal component regression (PCR), and least absolute shrinkage and selection operator (LASSO). Despite having different principles, the three predictive models identify two features as the most significant in predicting the interface nonlinearity: the crack aperture (opening) distribution and the distance to the crack tip. The differences between the three models and the physical interpretation of the data-driven predictions are discussed.
Multilayer weak shocks generated by restrike during underwater electrical explosion of Cu wires
Authors: Shi Huantong , Yin Guofeng , Fan Yunfei , Wu Jian , Li Xingwen , Murphy Anthony B.
Published: August 2019

Underwater electrical explosions of Cu wires were carried out on a microsecond time scale to produce underwater shock waves. Experimental results show that the radial density distribution of the water flow after restrike contains several oscillations, observed as ∼1 mm-spaced layers in the backlit streak images and laser shadowgraphs. The phenomenon is attributed to the partial reheating of the exploding product (EP) by an interior restrike arc, which stimulates a compression wave propagating back and forth radially in the EP. Simulations are used to support the interior breakdown scenario and to demonstrate that each reflection of the compression wave at the EP–water interface launches a weak shock into the water, forming a multilayer structure. As the surrounding metallic vapor is ionized due to radiation and thermal conduction from the arc, the highly conductive plasma channel continues to extend radially and launches the main compression wave, which drowns out the multilayers when the power injection is sufficiently high.
Management or missed opportunity? Mental health care planning in Australian general practice
Authors: Banfield Michelle , Farrer Louise M. , Harrison Christopher
Published: August 2019

General practice care plans are designed to improve the management of chronic illness, facilitating multidisciplinary care and enabling GPs and consumers to work collaboratively. Evidence suggests that they work well for chronic physical illnesses, but it is unclear if they operate as intended for people with mental disorders. The aims of this study were to: (1) compare rates of creation and review of GP care plans for mental disorders and type II diabetes; and (2) examine consumer experiences. Secondary analysis of 109589 recorded encounters from a national cross-sectional study in Australian general practice (2006–16) demonstrated that encounters involving creation of a care plan for depression or anxiety were significantly higher than those for diabetes, bipolar disorder and schizophrenia. Rates of review were commensurate with creation of plans for diabetes, but not for mental disorders. Eighteen people with a GP care plan completed an online survey about their experiences, reporting that care plans facilitated access to allied health professionals, but did not improve the quality of care they received. Findings suggest that care plans are underutilised for people with low prevalence mental disorders, and while they offer financial benefits to consumers, they may not result in ongoing, collaborative care.
Regulation of PRMT5–MDM4 axis is critical in the response to CDK4/6 inhibitors in melanoma
Authors: AbuHammad Shatha , Cullinane Carleen , Martin Claire , Bacolas Zoe , Ward Teresa , Chen Huiqin , Slater Alison , Ardley Kerry , Kirby Laura , Chan Keefe T. , Brajanovski Natalie , Smith Lorey K. , Rao Aparna D. , Lelliott Emily J. , Kleinschmidt Margarete , Vergara Ismael A. , Papenfuss Anthony T. , Lau Peter , Ghosh Prerana , Haupt Sue , Haupt Ygal , Sanij Elaine , Poortinga Gretchen , Pearson Richard B. , Falk Hendrik , Curtis David J. , Stupple Paul , Devlin Mark , Street Ian , Davies Michael A. , McArthur Grant A. , Sheppard Karen E.
Published: August 2019

Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors are an established treatment in estrogen receptor-positive breast cancer and are currently in clinical development in melanoma, a tumor that exhibits high rates of CDK4 activation. We analyzed melanoma cells with acquired resistance to the CDK4/6 inhibitor palbociclib and demonstrate that the activity of PRMT5, a protein arginine methyltransferase and indirect target of CDK4, is essential for CDK4/6 inhibitor sensitivity. By indirectly suppressing PRMT5 activity, palbociclib alters the pre-mRNA splicing of MDM4, a negative regulator of p53, leading to decreased MDM4 protein expression and subsequent p53 activation. In turn, p53 induces p21, leading to inhibition of CDK2, the main kinase substituting for CDK4/6 and a key driver of resistance to palbociclib. Loss of the ability of palbociclib to regulate the PRMT5–MDM4 axis leads to resistance. Importantly, combining palbociclib with the PRMT5 inhibitor GSK3326595 enhances the efficacy of palbociclib in treating naive and resistant models and also delays the emergence of resistance. Our studies have uncovered a mechanism of action of CDK4/6 inhibitors in regulating the MDM4 oncogene and the tumor suppressor, p53. Furthermore, we have established that palbociclib inhibition of the PRMT5–MDM4 axis is essential for robust melanoma cell sensitivity and provide preclinical evidence that coinhibition of CDK4/6 and PRMT5 is an effective and well-tolerated therapeutic strategy. Overall, our data provide a strong rationale for further investigation of novel combinations of CDK4/6 and PRMT5 inhibitors, not only in melanoma but other tumor types, including breast, pancreatic, and esophageal carcinoma.
Noncanonical mitochondrial unfolded protein response impairs placental oxidative phosphorylation in early-onset preeclampsia
Authors: Yung Hong Wa , Colleoni Francesca , Dommett Emilie , Cindrova-Davies Tereza , Kingdom John , Murray Andrew J. , Burton Graham J.
Published: August 2019

Significance

Preeclampsia endangers the lives and well-being of mother and baby. The syndrome is associated with placental dysfunction. High demand for energy to support active nutrient transport and hormone production increases placental susceptibility to mitochondrial stress. Here, we investigate mitochondrial activity and explore stress-response pathways in preeclamptic placentas. We demonstrate activation of noncanonical mitochondrial unfolded protein response (UPR
mt
) pathways associated with reduced CLPP, a key protease in UPR
mt
signalling, that compromises mitochondrial respiration. The changes can be recapitulated in trophoblast cells by hypoxia–reoxygenation. Either activation of UPR
mt
or knockdown of CLPP can sufficiently reduce mitochondrial respiration. Translation of CLPP is negatively regulated by the endoplasmic reticulum UPR pathway. Understanding mitochondrial stress provides new insights into the pathophysiology of early-onset preeclampsia.
Suzanne Eaton (1959–2019): A pioneer in quantitative tissue morphogenesis
Authors: Knust Elisabeth , Simons Kai
Published: August 2019

Knust and Simons commemorate the life of the eminent developmental biologist, Suzanne Eaton.
A computationally efficient algorithm to obtain an accurate and interpretable model of the effect of circadian rhythm on resting heart rate
Authors: Morelli Davide , Bartoloni Leonardo , Rossi Alessio , Clifton David A
Published: August 2019

Objective: Wrist-worn wearable devices equipped with heart rate (HR) sensors have become increasingly popular. The ability to correctly interpret the collected data is fundamental to analyse user’s well-being and perform early detection of abnormal physiological data. Circadian rhythm is a strong factor of variability in HR, yet few models attempt to accurately model its effect on HR. Approach: In this paper we present a mathematical derivation of the single-component cosinor model with multiple components that fits user data to a predetermined arbitrary function (the expected shape of the circadian effect on resting HR (RHR)), thus permitting us to predict the user’s circadian rhythm component (i.e. MESOR, Acrophase and Amplitude) with a high accuracy. Main results: We show that our model improves the accuracy of HR prediction compared to the single component cosinor model (10% lower RMSE), while retaining the readability of the fitted model of the single component cosinor. We also show that the model parameters can be used to detect sleep disruption in a qualitative experiment. The model is computationally cheap, depending linearly on the size of the data. The computation of the model does not need the full dataset, but only two surrogates, where the data is accumulated. This implies that the model can be implemented in a streaming approach, with important consequences for security and privacy of the data, that never leaves the user devices. Significance: The multiple component model provided in this paper can be used to approximate a user’s RHR with higher accuracy than single component model, providing traditional parameters easy to interpret (i.e. the same produced by the single component cosinor model). The model we developed goes beyond fitting circadian activity on RHR, and it can be used to fit arbitrary periodic real valued time series, vectorial data, or complex data.