bluuebunny/crossref_metadata_2025 huggingface dataset:
Industrial revolution 4.0 in industrial laundries and their information technologies landscape
Authors: Polívka Martin , Dvořáková Lilia
Published: October 2020

This paper presents the research results in the field of implementation of fourth industrial revolution technologies into the service sector, with a specific focus on the integration of Industry 4.0 technologies into corporate processes of industrial laundries. The theme covered was found topical following the analysis of practical needs and based on the specific nature of industrial laundry processes and only marginal interest paid in professional theory and discussions to the possibility and efficiency of the Industry 4.0 technologies implementation into non-production companies. Based on the analysis and evaluation of secondary data, advanced Industry 4.0 technologies have been identified which might lead to the increase of industrial laundries efficiency. Further, the methods of monitoring, structured interview and case study have been combined to design the integration of Industry 4.0 technologies into the system of existing information and communication technologies and systems. Based on a quality comparison, the case study and structured interview results have proven the benefits of implementation of automated identification and data collection technologies including the implementation of vertical integration of corporate information system and horizontal integration leading to the interconnection with customers in industrial laundries corporate processes.
Changes in the start-ups business models
Authors: Procházková Katarína
Published: October 2020

Research paper is summarizing results of project focus on business models and strategies of startups. The research was focused on identification of business models and strategies of startups. Research sample was creating from more than 70 startups at the beginning of the research and we finished research 3 years later with 53 startups. This research paper is partial output that analyze startups in global business environment in terms of doing business abroad and making strategic steps. The aim of paper is identify basic strategic steps and decision making of startups through selected indicators such as market presence and entry modes focusing on the last stage of research. Startups business model were also analyze and part of the output is mapping the shifts in business model Canvas of startups.
Successes and Failures of Family Business in Slovakia
Authors: Tóthová Alena , Tóth Miroslav
Published: October 2020

Family businesses are part of the world's economies, with an estimated 70-90% share of total performance. The history of family business in Slovakia is not continuous, so we can examine its level from the last 30 years of experience at most. The paper is focused on research of financial results of Slovak family enterprises, their confrontation with other types of enterprises, searching for trends in the level of their financial indicators and finally on the dependence between results and environment. In the research were used several methods, from which we can name mainly analysis, synthesis, comparison, mathematical-statistical methods. The obtained outputs are intended to identify strengths and weaknesses of family business in Slovakia.
DTI in der Diagnostik der zervikalen Myelopathie
Authors: Schöller Karsten , Siller Sebastian
Published: October 2020

Die degenerative zervikale Myelopathie (DCM) ist die häufigste Form der Rückenmarksaffektion im Erwachsenenalter. Die zugrundeliegenden pathophysiologischen Veränderungen sind komplex und eine operative Therapie ist in aller Regel spätestens dann notwendig, wenn relevante klinische Symptome einer stenosebedingten Rückenmarkskompression vorliegen. Für die Planung der Operation ist eine akkurate bildgebende Diagnostik essenziell. Diese soll dabei helfen, die zur klinischen Symptomatik beitragenden Wirbelsäulensegmente zu identifizieren.

Die konventionelle Magnetresonanztomografie (MRT) ist das heutzutage am häufigsten angewendete bildgebende Verfahren bei DCM, da sich v. a. T2-gewichtete MRT-Sequenzen hervorragend für die morphologische Beurteilung der Rückenmarkskompression und die Identifikation einer Myelomalazie („Myelopathiezeichen“) eignen. Insbesondere bei multisegmentalen degenerativen Veränderungen kann die Grenze der diagnostischen Aussagekraft des MRTs jedoch schnell erreicht werden.

Die Diffusion Tensor Bildgebung (diffusion tensor imaging, DTI) ist eine auf der MRT basierende, neuartige Untersuchungsmodalität, die auf der Messung der Diffusionseffekte von Wassermolekülen auf zellulärer Ebene basiert und eine Beurteilung der Integrität der weißen Rückenmarkssubstanz ermöglicht. Die beiden wichtigsten DTI-Größen, FA (fraktionelle Anisotropie) und ADC (apparent diffusion coefficient), stellen Surrogatparameter für das Ausmaß der strukturellen Myelonschädigung dar und zeigen Unterschiede zwischen DCM-Patienten und gesunden Probanden. Ein Vorteil dieser Technik könnte in einer sensitiven und frühen Detektion einer Rückenmarksschädigung liegen, zudem ist die Nutzung als prognostischer Marker oder bei der Operationsplanung denkbar.

Unser Artikel beschäftigt sich mit den Einsatzmöglichkeiten des DTI bei der zervikalen Myelopathie und gibt einen Ausblick auf mögliche zukünftige Entwicklungen.
„Paare mit Kinderwunsch sollten fair und offen beraten werden“
Authors: Kupka Markus S. , Becker Marion Anna
Published: October 2020

Experten-Interview | In Deutschland sind rund 1,4 Mio. Männer und Frauen ungewollt kinderlos. Die Reproduktionsmedizin bietet verschiedene Verfahren an, um den Betroffenen zu helfen. Im Interview mit DIE HEBAMME erläutert Kinderwunschexperte Prof. Dr. med. Markus S. Kupka, welche Behandlungsmöglichkeiten es gibt und für wen sie geeignet sind.
Aufklärung über die Gefahren des Schüttelns von Säuglingen und Kleinkindern
Authors: Königstein Astrid , Neumann Anna
Published: October 2020

Wenn Eltern ihren schreienden Säugling im Affekt schütteln, können sie ihrem Kind gravierende gesundheitliche Schäden zufügen oder es sogar töten. Seit 2017 klärt das Nationale Zentrum Frühe Hilfen mit Sitz in der Bundeszentrale für gesundheitliche Aufklärung im Auftrag des Bundesministeriums für Familie, Senioren, Frauen und Jugend über die Gefahren des Schüttelns von Säuglingen und Kleinkindern auf. Unterstützt wird es dabei vom bundesweiten „Bündnis gegen Schütteltrauma“. Ziel ist es, gemeinsam möglichst viele Familien und werdende Eltern zu erreichen. Hebammen sind hierbei wichtige Multiplikatorinnen.
Dietary Cysteine Intake is Associated with Blood Glutathione Levels and Isometric Strength
Authors: Margaritelis Nikos V. , Chatzinikolaou Panagiotis N. , Bousiou Flora V. , Malliou Vasiliki J. , Papadopoulou Sousana K. , Potsaki Panagiota , Theodorou Anastasios A. , Kyparos Antonios , Geladas Nikos D. , Nikolaidis Michalis G. , Paschalis Vassilis
Published: October 2020

Glutathione is the most abundant cellular antioxidant and regulates redox homeostasis. Healthy individuals with certain antioxidant inadequacies/deficiencies exhibit impairments in physiological functions. The aim was to investigate whether low levels of dietary cysteine intake are associated with a) lower erythrocyte glutathione, b) increased plasma F2-isoprostanes, and c) impaired muscle function. Towards this aim, we recorded the dietary intake of the three amino acids that synthesize glutathione (i. e., glutamic acid, cysteine, and glycine) in forty-one healthy individuals, and subsequently measured erythrocyte glutathione levels. Maximal isometric strength and fatigue index were also assessed using an electronic handgrip dynamometer. Our findings indicate that dietary cysteine intake was positively correlated with glutathione levels (r=0.765, p<0.001). In addition, glutathione levels were negatively correlated with F2-isoprostanes (r=− 0.311, p=0.048). An interesting finding was that glutathione levels and cysteine intake were positively correlated with maximal handgrip strength (r=0.416, p=0.007 and r=0.343, p=0.028, respectively). In conclusion, glutathione concentration is associated with cysteine intake, while adequate cysteine levels were important for optimal redox status and muscle function. This highlights the importance of proper nutritional intake and biochemical screening with the goal of personalized nutrition.
Tutankhamun’s Antimalarial Drug for Covid-19
Authors: Sommer Andrei P. , Försterling Horst-Dieter , Sommer Katlin E.
Published: October 2020

Drug repositioning is a strategy that identifies new uses of approved drugs
to treat conditions different from their original purpose. Current efforts
to treat Covid-19 are based on this strategy. The first drugs used in
patients infected with SARS-CoV-2 were antimalarial drugs. It is their
mechanism of action, i. e., rise in endosomal pH, which recommends
them against the new coronavirus. Disregarding their side effects, the study
of their antiviral activity provides valuable hints for the choice and
design of drugs against SARS-CoV-2. One prominent drug candidate is
thymoquinone, an antimalarial substance contained in Nigella sativa
– most likely one of the first antimalarial drugs in human history.
Since the outbreak of the pandemic, the number of articles relating
thymoquinone to Covid-19 continuously increases. Here, we use it as an
exemplary model drug, compare its antiviral mechanism with that of
conventional antimalarial drugs and establish an irreducible parametric
scheme for the identification of drugs with a potential in
Covid-19.Translation into the laboratory is simple. Starting with the
discovery of Nigella sativa seeds in the tomb of Pharaoh Tutankhamun, we
establish a physicochemical model for the interaction of thymoquinone with
both coronavirus and cells. Exploiting the predictive capability of the
model, we provide a generalizable scheme for the systematic choice and
design of drugs for Covid-19. An unexpected offshoot of our research is that
Tutankhamun could not have died of malaria, a finding contrary to the
mainstream theory.
Electronic Health Records Aggregators (EHRagg )
Authors: Prados-Suárez Belén , Molina Fernández Carlos , Yañez Carmen Peña
Published: October 2020

Background Integration of health data systems is an open problem. Most of the active initiatives are based on the use of standards. However, achieving a widely and generalized compliment of such standards still seems a costly task that will take a long time to be completed. Even more, most of the standards are proposed for a specific use, without integrating other needs.

Objectives We propose an alternative to get a unified view of health-related data, valid for several uses, that unites heterogeneous data sources.

Methods Our proposal integrates developments made so far to automatically learn how to extract and convert data from different health-related systems. It enables the creation of a single multipurpose point of access.

Results We present the EhRagg notion and its related concepts. EHRagg is defined as a middleware that, following the FAIR principles, integrates health data sources offering a unified view over them.
Galen: The First Cardiac Surgeon?
Authors: Rajabnejad Mohammad Reza , Ranjbar Maryam , Al-Attar Mohammad
Published: October 2020

It is widely believed that the first and the second pericardium surgeries were done in the nineteenth century by Francisco Romero and Dominique Jean Larrey, respectively; however, Galen was the first surgeon who proceeded with pericardiectomy. This ancient case report of sternum osteomyelitis and pericardiectomy illuminates some dark part of the history of medicine and the ability of physicians in that era.
Fatores de risco modificáveis para fasciíte plantar em pacientes não atletas e proposta de um novo sistema de avaliação objetiva – RKISP
Authors: Choudhary Ranjeet , Kunal Kishor
Published: October 2020

Objetivo Determinar os fatores de risco modificáveis associados à gravidade da fasciíte plantar e formular um sistema objetivo de pontuação para indexação da doença na população não atlética.

Métodos Estudo observacional prospectivo. A principal medida de desfecho foi a associação de um fator de risco modificável, mensurada pelo valor de R (coeficiente de Pearson) e pelo nível de significância de p < 0,05.

Resultados Em uma amostra de 50 pacientes, o índice de massa corporal (IMC) e calçados com amortecimento inadequado foram associados de maneira significativa à dor na fasciíte plantar. Todos os demais fatores de risco eram não modificáveis ou não apresentaram associação significativa.

Conclusão Com base nos dados à disposição e sua interpretação, um índice, denominado Índice de Ranjeet-Kunal de Pontuação da Fasciíte Plantar (RKISP, em inglês) , foi formulado e utilizado com sucesso não apenas na classificação da fasciíte plantar, mas também na determinação do prognóstico de seu tratamento conservativo, auxiliando a escolha da modalidade terapêutica.
A avaliação do método tomográfico glenoid track na ressonância magnética/artro RM
Authors: Godinho Andre Couto , Godinho Pedro Couto , França Flávio de Oliveira , Ribeiro Elísio José Salgado , de Toledo Daniel Carvalho , Franco Guilherme Henrique
Published: October 2020

Objetivo Comparar a avaliação do método glenoid-track (GT) em exames de tomografia computadorizada com reconstrução 3-D (TC-3D) com a avaliação realizada em exames de ressonância magnética (RM) e/ou artro-ressonância magnética (ARM).

Métodos Quarenta e quatro ombros com diagnóstico clínico e radiográfico de instabilidade anterior traumática foram avaliados por meio de exames de TC-3D, RM e/ou ARM. As variáveis GT, intervalo de Hill-Sachs (IHS) e a perda óssea da glenoide (POG) foram realizadas por um médico radiologista, utilizando imagens de TC-3D, e classificadas em on-track/off-track. Três cirurgiões cegos à avaliação do radiologista realizaram o mesmo método utilizando RM/ARM. O estudo realizou análise descritiva, de variância, de associação da discordância de resultados, de concordância e curva característica de operação do receptor.

Resultados Os resultados dos 4 examinadores foram totalmente concordantes em 61,4%. A RM/ARM diagnosticou lesões off-track com a sensibilidade variando de 35 a 65%, e lesões on-track com a especificidade variando de 91,67 a 95,83%. A acurácia variou de 68,1 a 79,5%. A maior divergência de dados ocorreu para o diagnóstico por RM/ARM de lesões off-track. A maior variabilidade dos dados ocorreu para o cálculo do IHS. Valores maiores de IHS e de POG foram associados a maior discordância entre os examinadores. A RM/ARM apresentou menor medida de valores de IHS quando comparado com a TC-3D. Ocorreu apenas moderada concordância no método GT entre a TC e a RM/ARM (Kappa 0,325–0,579).

Conclusão A RM/ARM apresentou baixa acurácia e moderada concordância para o método GT, devendo ser utilizada com cautela por cirurgiões.
Current and Future Medical Therapies for Adenomyosis
Authors: Cope Adela G. , Ainsworth Alessandra J. , Stewart Elizabeth A.
Published: October 2020

There is no approved medical therapy for adenomyosis and limited evidence to guide treatments in part due to the complexity of nonhistologic diagnosis and the prevalence of concomitant gynecologic conditions. Most available evidence focuses on the treatment of heavy menstrual bleeding, painful menses, and pelvic pain. Data evaluating fertility outcomes, sexual function, and quality of life following treatment are lacking. Additionally, there is no disease-specific measure of quality of life for adenomyosis. The levonorgestrel-releasing intrauterine system appears to be the most effective first-line therapy based on efficacy compared with oral agents, maintenance of steady-state hormonal levels, and contraceptive benefit. In areas where it is marketed, the progestin dienogest appears superior to combined oral contraceptives. Long-acting gonadotropin-releasing hormone agonists are effective and should be considered second-line therapy but are limited by hypogonadal effects. Additional data regarding oral gonadotropin-releasing hormone antagonists are required. While aromatase inhibitors demonstrate improvement in heavy menstrual bleeding and pelvic pain, further research is needed to determine their role in the management of adenomyosis. Progesterone receptor modulators may have a role for this disease if released again to market with appropriate safety parameters. Finally, modulation of prolactin and/or oxytocin may provide novel nonsteroidal treatment options.
Treatment Strategies for Unexplained Infertility
Authors: Wang Rui , van Eekelen Rik , Mochtar Monique H. , Mol Femke , van Wely Madelon
Published: October 2020

Unexplained infertility is a common diagnosis among couples with infertility. Pragmatic treatment options in these couples are directed at trying to improve chances to conceive, and consequently intrauterine insemination (IUI) with ovarian stimulation and in vitro fertilization (IVF) are standard clinical practice, while expectant management remains an important alternative. While evidence on IVF or IUI with ovarian stimulation versus expectant management was inconclusive, these interventions seem more effective in couples with a poor prognosis of natural conception. Strategies such as strict cancellation criteria and single-embryo transfer aim to reduce multiple pregnancies without compromising cumulative live birth. We propose a prognosis-based approach to manage couples with unexplained infertility so as to expose less couples to unnecessary interventions and less mothers and children to the potential adverse effects of ovarian stimulation or laboratory procedures.
Investigation of the spatial distribution of hot carriers in quantum-well structures via hyperspectral luminescence imaging
Authors: Esmaielpour Hamidreza , Lombez Laurent , Giteau Maxime , Delamarre Amaury , Ory Daniel , Cattoni Andrea , Collin Stéphane , Guillemoles Jean-François , Suchet Daniel
Published: October 2020

Observation of robust hot carrier effects in quantum-well structures has prompted hopes to increase the efficiency of solar cells beyond the Shockley–Queisser limit (33% for single junction solar cells at AM1.5G). One of the main studies in hot carrier effects is the determination of carrier temperature, which provides information on the thermalization mechanisms of hot carriers in semiconductor materials. Here, we investigate the spatial distribution of photo-generated hot carriers in a InGaAs multi-quantum-well structure via hyperspectral luminescence imaging. We discuss proper methods of extracting the temperature of carriers from a photoluminescence spectrum. Robust hot carrier effects are observed at the center of the laser spot at various lattice temperatures. In addition, it is seen that the local carrier temperature scales linearly with the local laser intensity as long as the illumination exceeds a threshold power; the carrier temperature at regions with local intensities below the threshold drops to the lattice temperature, i.e., experiences no hot carrier effects. Moreover, at large distances from the concentrated light, where the level of illumination is negligible, evidence of carrier radiative recombination is observed, which is attributed to carrier diffusion in the planar structure. The results of this study can be applied to investigate the influence of carrier diffusion and thermoelectric effects on the thermalization of hot carriers.
Exploring the measure of potentially avoidable general practitioner-type presentations to the emergency department in regional Queensland using linked, patient-perspective data
Authors: O'Loughlin Mary , Mills Jane , McDermott Robyn , Harriss Linton R
Published: October 2020

ObjectiveTo explore measures of potentially avoidable general practitioner (PAGP)-type presentations to the emergency department (ED) of a large regional hospital in northern Queensland.
MethodsLinkage of an ED administrative dataset to a face-to-face patient survey of local residents (n=1000); calculation of Australian Institute of Health and Welfare (AIHW) and Australasian College of Emergency Medicine (ACEM) measures of PAGP-type presentations to the ED; and exploration of these measures with patient-perspective linked data.
ResultsPAGP-type presenters to the ED were younger in age (median age in years: total cohort: 49; AIHW 38, P<0.001; ACEM 36, P<0.001); with the odds of having a chronic condition being less likely for AIHW PAGP-type presenters than other ED presenters (OR (95% CI) 0.54 (0.38–0.77): P=0.001)) after adjustment for age. PAGP-type presenters nominated reasons of convenience rather than urgency as their rationale for attending the ED, irrespective of measure. The number of PAGP-type presentations to the ED identified by the AIHW measure was more than three-fold higher than the ACEM measure (AIHW: n=227; ACEM: n=67). Influencing factors include the low proportion of ED attendees who had a medical consultation time of <1h at this hospital site (1-month survey period: 17.8%); and differences between the patient self-report and ED administrative record for ‘self-referral to the ED’ (Self-referred: Survey 71% vs EDIS 93%, P<0.001).
ConclusionsIdentification of PAGP-type presentations to the ED could be enhanced with improvements to the quality of administrative processes when recording patient ‘self-referral to the ED’, along with further consideration of hospital site variation for the length of medical consultation time.
What is known about the topic?PAGP-type presentations to the ED are an Australian National Healthcare Agreement progress indicator. Methods of measuring this indicator have been under review since 2012 and debate remains on how to accurately determine the measure.
What does this paper add?By using patient perspective-linked data to explore different measures of PAGP-type presentations to EDs, this paper identifies issues with measure elements and suggests ways to improve these measures.
What are the implications for practitioners?Measure elements of patient ‘self-referral to the ED’ and ‘medical consultation time’ require further consideration if they are to be used to measure PAGP-type presentations to the ED.
A codeveloped management tool to determine harvest limits of introduced mud crabs,
Authors: Hurley Kaleonani K. C. , Kapur Maia Sosa , Siple Margaret , Kotubetey Keli‘iahonui , Hi‘ilei Kawelo A. , Toonen Robert J.
Published: October 2020

Hawaiian fishponds, or loko i‘a, are ancient aquaculture systems and models of sustainable aquatic resource management from traditional Native Hawaiian harvest practices. Of the 488 fishponds documented in ancient Hawai‘i, only 38 are currently actively managed. Building on Indigenous and local knowledge, fishponds are being adapted to current community needs. Functional fishponds perpetuate culture, improve food security, enhance ecosystem services and transform conservation biology through Indigenous perspectives. Here we examine how Indigenous practices effectively maintain sustainable harvest of an introduced, but economically important, crab species, the mud crab, Scylla serrata (Forskål 1775). The State of Hawai‘i has only a size limit, and no bag limits, for this species. With Indigenous management in a Hawaiian fishpond, limits are set and enforced in response to fluctuations in catch. We used a mark–recapture experiment to parameterise a size-structured population model, which we used to investigate the impact of changing harvest rates. Throughout the study period of 2017–20, the mean number of crabs per harvest was 28 individuals (s.d. = 7) and average catch per unit effort was 0.20 crabs per trap-hour (s.d. = 0.054). During winter, catch per unit effort was lower but mean crab size was larger than during summer. Model simulations indicated that current Indigenous practices are less likely to cause a decline in population growth rate than a strict size limit. Using information from Indigenous harvest practices and the mark–recapture study, we codeveloped a versatile crab population model that can be tailored to changing management objectives.
Interface and surface stabilization of the polarization in ferroelectric thin films
Authors: Gattinoni Chiara , Strkalj Nives , Härdi Rea , Fiebig Manfred , Trassin Morgan , Spaldin Nicola A.
Published: October 2020

Significance

With an ever-increasing societal demand for energy for electronic devices and in the face of the current climate issues, the need for low-energy-consuming electronics has never been greater. Ferroelectrics are promising energy-efficient device components for digital information storage, with the functionality relying on the manipulation of their polarization in ultrathin films. Polar discontinuities at the thin film interfaces and surfaces, however, can cause loss of polarization and thus functionality. Here we show how the interface and surface influence the overall polarization of the thin film. We show that the structure of the interface and surface can be tailored toward a specific polarization direction and strength, and that great control in the engineering of ferroelectrics thin films can be achieved.
Evaluation of Climatic Comfort of Living Environment based on Age Differentials in Beijing-Tianjin-Hebei Area
Authors: Liu Siyu , Long Buju , Pan Zhihua , Lun Fei , Song Yu , Yuan Weiying , Huang Na , Zhang Ziyuan , Ma Shangqian
Published: October 2020

Somatosensory comfort is mainly determined by the Temperature and Humidity Index (THI) with Wind Efficiency Index (WEI), but this conventional usage of these indicators does not capture the age-related differentials. Here we resolved this gap with a modification of the climatic comfort definition and method in a national standard, denoted as the Relative Climate Sensitive Index (RCSI), which incorporated the age-related vulnerability scores determined through online questionnaires with a scoring method, for each of the age-related and adaptive climatic comfort responses to changes in residence with Beijing-Tianjin-Hebei (BTH) region as an example. First, the result showed that the human comfort of living environment decreased with age in the BTH region, implicating age obviously impacted comfort, and weak adaptability made the elderly the relatively most high-risk group – their suitable region was less than a quarter of the whole study region. Second the adverse effects of persistent hot weather on comfort, indicating global warming as the leading driver of dwindling comfort over recent years. As the warming was more significant in the southeastern part, all these forces combined had there a hotspot, appealing for extra attention. Last this improved evaluation accorded with actual situation to captured high-risk groups with their distributions.
PET-enabled dual-energy CT: image reconstruction and a proof-of-concept computer simulation study
Authors: Wang Guobao
Published: October 2020

Standard dual-energy computed tomography (CT) uses two different x-ray energies to obtain energy-dependent tissue attenuation information to allow quantitative material decomposition. The combined use of dual-energy CT and positron emission tomography (PET) may provide a more comprehensive characterization of disease states in cancer and other diseases. However, the integration of dual-energy CT with PET is not trivial, either requiring costly hardware upgrades or increasing radiation exposure. This paper proposes a different dual-energy CT imaging method that is enabled by PET. Instead of using a second x-ray CT scan with a different energy, this method exploits time-of-flight PET image reconstruction via the maximum likelihood attenuation and activity (MLAA) algorithm to obtain a 511 keV gamma-ray attenuation image from PET emission data. The high-energy gamma-ray attenuation image is then combined with the low-energy x-ray CT of PET/CT to provide a pair of dual-energy CT images. A major challenge with the standard MLAA reconstruction is the high noise present in the reconstructed 511 keV attenuation map, which would not compromise the PET activity reconstruction too much but may significantly affect the performance of the gamma-ray attenuation image for material decomposition. To overcome the problem, we further propose a kernel MLAA algorithm to exploit the prior information from the available x-ray CT image. We conducted a computer simulation to test the concept and algorithm for the task of material decomposition. The simulation results demonstrate that this PET-enabled dual-energy CT method is promising for quantitative material decomposition. The proposed method can be readily implemented on time-of-flight PET/CT scanners to enable simultaneous PET and dual-energy CT imaging.
A systematic study on optoelectronic properties of Mn4+-activated Zr-based hexafluoride red phosphors X2ZrF6 (X = K, Na, Cs): first-principles investigation and prospects for warm-white LEDs applications
Authors: Abbas Zeesham , Azam Sikander , Bashir Azmat Iqbal , Marriam Asia , Waqas Muhammad , Alshahrani Thamraa , Haq Bakhtiar Ul
Published: October 2020

The quest for developing energy-efficient and environment-friendly phosphors for lighting devices such as light-emitting diodes (LEDs) is on rise to meet the future energy challenges. In this connection, phosphor-converted white LEDs are promising candidates for the next generation state-of-the-art solid-state lighting technology to substitute the traditional lighting devices such as fluorescent lamps, incandescent lamps, halogen lamps, and backlights for liquid crystal displays. Hereby, we report a systematic analysis on the optoelectronics properties of Zr-based Mn4+-activated phosphors X2ZrF6 (X = K, Na, Cs) for potential optoelectronics and photoluminescence device applications such as LEDs. For the comparative analysis of the first-principles calculations based on full-potential linearized augmented plane wave DFT procedure, we employed spin polarized GGA and GGA + U scheme of exchange and correlation energy potentials. In contrast to parent X2ZrF6 compounds, the band gaps of the Mn-doped X2MnF6 compounds have been lowered considerably. The improvement on band-gap values with GGA + U method reaffirms the famous drawback of GGA-based DFT methods regarding the underestimation of band gaps in highly correlated systems. For the prospects of materials regarding optoelectronics and photoluminescence applications, we first time report a detailed systematic analysis of optical properties such as dielectric functions, energy loss function, reflectivity, absorption coefficient, refractive index and optical conductivity. The materials are weakly photons reflector in IR and visible regions while they are strong photons absorbers in the UV region. In the absence of experimental evidences, indirect evidence of the wide band-gaps of K2ZrF6 and Na2ZrF6 compounds is ascertained via doping of Mn4+ ions. Besides, as all the energy levels of Mn4+ ions are around 4 eV these can also be observed in the experimental absorption spectra.
Numerical investigation of 1550 nm passively mode-locked diode lasers with different gain and absorber configurations
Authors: Aksakal Rukiye , Duman Caglar , Cakmak Bulent
Published: October 2020

In this study, passively mode-locked semiconductor lasers with a central wavelength of 1550 nm are theoretically investigated, consisting of gain and absorption sections. Variation of carrier density with time and pulse profiles of the laser outputs are obtained. Comparative results are obtained for different lengths of the gain sections and absorber sections. In addition, the results are also examined while the absorption section is located between two gain sections and at the far end. It has been found that the devices with two gain sections have higher power and shorter pulse width when the absorber section is located between the two gain sections. Finally, ultrashort stable optical pulses with nearly 800 mW peak power and 1.57 ps duration have been obtained from mode-locked laser diodes with two gain sections and one absorber section located between.
High-resolution two-dimensional atomic microscopy in a tripod-type four-level atomic medium via standing wave fields
Authors: Idrees Muhammad , Ullah Muhib , Amin Bacha Bakth , Ullah Arif , Wang Li-Gang
Published: October 2020

We present an efficient two-dimensional atomic localization in a tripod-type four-level atomic medium using standing-wave fields. The localization behavior is significantly
improved, and the maximum localization probability can be achieved under suitable conditions within the one-wavelength domain. Multiple sharp localized peaks are observed in the one-wavelength domain through examination of the absorption of the weak probe field, and theoretically, high-resolution and high-precision atomic localization can be achieved within a region smaller than λ/12 × λ/12, via the exploitation of quantum-coherence effects in laser–matter interactions. The spatial resolution of the atomic localization is extensively improved, compared to the cases with or without microwave fields studied previously. We believe that the results revealed here might have potential applications for atomic nanolithography, neutral-atom laser cooling and trapping, Bose–Einstein condensation and the center-of-mass wave-function measurements.
Towards a mathematics textbook for supporting 21st century learning: The student perspective
Authors: Kristanto Y D , Santoso E B
Published: October 2020

There is a need to provide 21st century learning through mathematics textbooks. To give valuable input to such an effort, students’ perspective needs to be considered since the students are the ones that get impacted from the effort. Therefore, the present study aims to describe students’ perspective regarding the effort in integrating 21st century learning and mathematics textbook. The study employed mixed methods with a survey approach to investigate the students’ perspective. The findings of this study uncover critical components that should be considered in designing a mathematics textbook for supporting 21st century learning. Based on the findings, a set of recommendations is proposed for a textbook designer.
Substation Equipment Fault Identification Based on Infrared Image Analysis
Authors: Yilin Jin , Jian Sun
Published: October 2020

As a key part of the power system, the substations undertake important work. With the development and construction of smart grids, the status data, image monitoring data, and environmental meteorological data of power systems are gradually being integrated and shared on a unified platform. Traditional models based on theoretical analysis are difficult to deal with multi-dimensional, massive data set information. Under this background, starting from the inherent law of the data itself, the use of machine learning methods combined with the infrared image data of the equipment can achieve intelligent identification and early warning of substation equipment failures. This paper first uses the convolutional neural network to identify the substation equipment in the picture, and then combines the infrared image to perform image registration. Finally, the deep belief network is used to determine whether the device is in wrong condition. The overall substation equipment fault identification is tested on real data, and the experimental results show that the proposed method has high accuracy.
Detection of Transient Junction Temperature Characteristics of High Power IGBT
Authors: Yong Tang , Bo Wang , Hong Chen Yong
Published: October 2020

In this paper, Insulated Gate Bipolar Transistor (IGBT), which is the most widely used full-control power electronic device, is taken as the research object. Under the special working mode of short-time intermittent pulse, with the increase of conduction current, the chip junction temperature of high-power IGBT will rise sharply and fluctuate greatly, causing the operating characteristics of the device to be greatly affected by temperature. The commonly used method of measuring the bottom plate shell temperature with thermocouples and then estimating the steady junction temperature can no longer meet the demand. Firstly, the fluctuation characteristics of junction temperature of high-power IGBT are analyzed. Then, a high-speed infrared thermal imaging device is used to carry out real-time junction temperature detection. The distribution and rising process of instantaneous junction temperature on the chip surface are obtained, which further verifies the correctness of theoretical analysis. The research has important guiding significance for IGBT application design under short-time intermittent pulse operation mode, and also has certain reference value for general operation mode.
Recognition Method of Aerial Insulator Defects Based on Deep Learning
Authors: Wang J F
Published: October 2020

Aiming at the problem of low accuracy of aerial photography insulator defect identification during UAV patrol, a method of insulator defect identification and positioning based on improved YOLOv3 target detection model is proposed. This method uses asymmetric convolutional block (ACB) as the structural block of the convolutional neural network model in the training phase. On the basis of not increasing the inference time, the depth of neural network learning is improved. At the same time, the feature map combination of the pyramid multi-scale detection model is improved, and the distance index parameters of the K-means ++ algorithm are optimized, which is used for target prior frame clustering. The experimental results show that the improved method proposed in this paper improves the recognition accuracy of small defective targets. Without reducing the speed of inference, the average accuracy is increased from 84.5% to 91.9%, which meets the requirements of intelligent inspection of UAVs for overhead transmission lines.
Study on the Temperature Distribution of UHV Arrester Considering the Influence of Wind Speed and Sunlight
Authors: Zhang Pipei , Shi Wei , Wang Peng , Wang Jiangwei , Sun Jingwen
Published: October 2020

Infrared temperature measurement plays an important role in the live detection of UHV arrester with its advantages of high efficiency and accuracy. However, the surface temperature of arrester will be affected by wind speed, sunlight and other external factors, which brings certain difficulties to infrared temperature measurement and fault diagnosis. Based on the principle of finite element, this paper established a three-dimensional temperature field simulation model of UHV AC arrester coupled with thermoelectricity, so as to use the model to simulate and analyze the temperature distribution of arrester under the influence of different wind speed and sunlight. The results show that the increase of wind speed strengthens the air convection and heat dissipation, which makes the maximum surface temperature decrease and the temperature rise decrease due to the internal defect heating of the arrester; the surface temperature of the arrester increases with the increase of solar radiation intensity, and the temperature of the sunny side is higher than that of the back, but the change of temperature rise is not great. The conclusion can be used as a reference for infrared temperature measurement of arrester in nonideal environment.
An Improved Control Strategy to Suppress the DC-Link Voltage Fluctuation for PMSG Wind Turbines
Authors: Wang Peng , Li Jie , Shi Wei
Published: October 2020

Frequency droop control can provide active power for permanent magnet synchronous generator (PMSG) wind turbines when grid frequency varies. However, it would cause dc-link voltage fluctuations. According to the law of the dc-link voltage fluctuations, a improved feedforward control method is proposed to limit voltage fluctuations through adjusting the feedforward coefficient from a fixed value to an variable value in this paper. Compared with the traditional current feedforward control method, it has better performance in stabilizing the dc-link voltage. Results demonstrate that the dc-link voltage fluctuations can be reduced by 70% in some specified cases, which proves that the proposed strategy can be applied to protect dc-link capacitor when PMSG wind turbines provide system inertia supports by frequency droop control. PMSG wind turbines can work as traditional thermal power to provide system inertia supports when grid frequency varies. The analysis results is very beneficial to widely application of PMSG wind turbines.
Reactive Power Optimization of Power Grid based on TTGA Hybrid Algorithm
Authors: Sun Lei , Jing Feng , Sun Fan , Guo Hongyan , Xiong Dengyu , Feng Hanfu , Zhang Lu
Published: October 2020

A new hybrid algorithm named TTGA hybrid algorithm which means genctic and tabu hybrid algorithm (TGA) with optimized tent mapping is proposed in this paper, through the research of tabu search(TS), genetic algorithm (GA)and chaotic algorithm(COA)[1].Based on evolutionary group generated by GA, auxiliary group formed by optimized tent mapping are ledinto group through specific selection mechanism so that the group become more diverse and effective. And in the meanwhile the tabu list is used to add a memory so that a similarity judgment mechanism is set based on the same individuals among group which provides a basis for using the TS operator to realize local fine search, so the tabu search plays the role of avoiding roundabout. In the new algorithm the introduction of TS ensures the capacity of hill climbing and refined search while the diversity of population and the effectiveness of evolution is assured by the regularity and ergodicity of chaotic. In this paper GA, IGA and TGA and TTGA is used in reactive power optimization of power grid, the results show that TTGA has the best performance on convergence and overall search.
Probabilistic Wind Speed Forecasting based on Minimal Gated Unit and Quantile Regression
Authors: Chen Tianyang , Qian Zheng , Jing Bo , Wan Jiangwen , Zhang Fanghong
Published: October 2020

High-quality wind speed forecasting (WSF) is of great significance to the power system planning and operation. In this paper, a hybrid method based on Minimal Gated Unit (MGU) and Quantile Regression (QR) is proposed for 2-hour WSF. Firstly, abnormal data is filtered by using the operating mode of SCADA system and Linear Interpolation algorithm is used for missing data imputation. Secondly, this paper embeds conditional quantile as an internal unit of MGU network. We estimate the parameters of MGU network under different quantile conditions, and calculate output under each quantile condition to obtain probabilistic WSF. At last, SCADA data collected from three wind turbines is applied to test the model performance. Both point and interval evaluation criteria are applied to evaluate the performance of models. The results show that the proposed model can obtain multi-step WSF with both point and interval prediction, compared with typical methods, it has higher accuracy in interval predictions and lower computation cost.
Processor-in-the-Loop Simulation of Three Port DC/DC Converter for DC Power Generation and Distribution System
Authors: Yang Yang , Jia Yiting , Li Anshou , Zhang Hua , Wang Zicai
Published: October 2020

Offline microgrid systems often use DC power generation and distribution systems. The spacecraft power system is a typical application of this system. The demand for massive, intensive launch and diversified functions in new aerospace applications puts forward requirements for off-the-shelf sales, fault tolerance, and rapid integration for the spacecraft power system. This article uses a three-port converter SRB3C to design a scalable DC power generation and distribution system with MPPT and flexible parallel ability. The power converter uses TMS320F28335 as a microcontroller to realize MPPT, droop control, current and voltage closed-loop control, and other functions. To fully verify the system and ensure the reliability of the spacecraft, the processor-in-the-Loop simulation model of the system is built to verify the binary program running in the processor under various operating conditions. The results show that the DC power generation and distribution system composed of SRB3C can meet the needs of spacecraft applications.
International Practice of Improving Power System Flexibility and Its Enlightenment to China
Authors: Cui Fubo , Hu Yuou , Zhang Tao , Zhang Jing , Liao Zhengkan , Zhao Guixin
Published: October 2020

With the rapid increase in the proportion of renewable energy in the power system, the volatility of renewable energy output has greatly increased the risk of power system operation and brought about the need for power system flexibility. A reasonable market mechanism in the electricity market can stimulate flexibility resources and fully exploit the flexibility of the system, which plays an important role in the efficient and safe operation of the power system. This paper studies several countries or regions that have a high share of renewable energy and have established relatively mature power markets, and then analyzes and compares the power system flexibility needs of these regions and the market mechanisms used to increase flexibility. Finally, the enlightenment of international practice to China based on the current situation is summarized.
GIS Mechanical Fault Diagnosis Method Based on Middle Time Mel Cepstrum Coefficient
Authors: Jiang Yi , Xu Mingyue , Lin Rui , Hong Lezhou , Lu Guosheng , Li Zhe
Published: October 2020

Mechanical fault is a common fault of gas insulated switchgear (GIS). If not found in time, it will cause major safety hazards such as opening and closing fault. In this paper, a diagnosis method based on improved Mel cepstrum coefficient for GIS mechanical fault on-line monitoring is proposed. Firstly, the Mel frequency cepstral coefficients (MFCC) are extracted from the preprocessed sound signals; in order to adapt to the characteristics of smooth sound energy change in GIS operation, the MFCC is optimized to obtain improved features; Support Vector Machine (SVM) is introduced to build a GIS mechanical fault diagnosis model based on acoustics and uses bagging algorithm to integrate the SVM model. In this study, mechanical fault is simulated on real GIS to obtain real fault sound signals for training and testing. The experimental results show that compared with the traditional MFCC, the improved MFCC has a higher recognition accuracy in GIS fault sound recognition system. The F1-score is generally over 80%, and the F1-score of specific mechanisms can even reach 99%.
Addendum to ‘Assessing ExxonMobil’s climate change communications (1977–2014)’ Supran and Oreskes (2017 Environ. Res. Lett. 12 084019)
Authors: Supran Geoffrey , Oreskes Naomi
Published: October 2020

In our 2017 study ‘Assessing ExxonMobil’s climate change communications (1977–2014)’, we concluded that ExxonMobil has in the past misled the public about climate change. We demonstrated that ExxonMobil ‘advertorials’—paid, editorial-style advertisements—in The New York Times spanning 1989–2004 overwhelmingly expressed doubt about climate change as real and human-caused, serious, and solvable, whereas peer-reviewed papers and internal reports authored by company employees by and large did not. Here, we present an expanded investigation of ExxonMobil’s strategies of denial and delay. Firstly, analyzing additional documents of which we were unaware when our original study was published, we show that our original conclusion is reinforced and statistically significant: between 1989–2004, ExxonMobil advertorials overwhelmingly communicated doubt. We further demonstrate that (i) Mobil, like Exxon, was engaged in mainstream climate science research prior to their 1999 merger, even as Mobil ran advertorials challenging that science; (ii) Exxon, as well as Mobil, communicated direct and indirect doubt about climate change and (iii) doubt-mongering did not end after the merger. We now conclude with even greater confidence that ExxonMobil misled the public, delineating three distinct ways in which they have done so.