bluuebunny/crossref_metadata_2025 huggingface dataset:
Using critical incidents for professional development with Iranian novice English teachers
Authors: Nejadghanbar Hassan
Published: May 2020

This study explored the effects of teachers’ individual reflection (IR) and group reflection (GR) on critical incidents (CIs). A group of preservice teachers (N = 7) were presented with real instances of CIs to consider during 12 teacher training sessions. In each session, the trainees read the first part of a CI, describing what happened, when it happened, and who was involved in the incident. Then they described how they would respond to a similar CI in their future classes. Next, they read and discussed the second part of the CI, which contained the reaction of the original teacher to that CI. After that, the trainees shared and discussed their own and the original teacher’s response to the CI through GR. Finally, they were asked to write a second response to the original CI. The trainees’ IR and GR were tabulated and compared to see how GR impacted their reactions. After completing the program, they were asked to write reflection journals describing their evaluation of the activities they had taken part in. Thematic analysis of reflection journals led to the emergence of themes revealing teachers’ positive evaluation of the reflection on CIs.
Local integration and co‐evolution of internationalizing Chinese firms
Authors: Li Wei , Hendrischke Hans
Published: May 2020

This study investigates the integration of internationalizing Chinese firms into local host markets. We explore the market‐driven investment of a new wave of Chinese private and local state‐owned firms in Australia since 2012, which has replaced the initial large‐scale investment in resources by central state‐owned enterprises. Using an in‐depth analysis of nine Chinese firms operating in various sectors of the Australian market, we argue that market integration, adaptation, and bilateral institution‐building through co‐evolution and empowerment of local subsidiaries of Chinese multinational enterprises results in entrepreneurial autonomy and characterizes a new generation of Chinese investors. We propose that Chinese multinational subsidiaries have transferred domestic practices to the Australian market and have reconfigured domestic and host market resources to gain a competitive advantage in their original investment industry and new industries. Our study advances middle‐range theory building and provides a practical understanding of the strengths and weaknesses of Chinese investors, their potential to disrupt local markets, and their responsiveness to market‐oriented institutional guidance. The results of this study suggest that the bilateral institution‐building and resource reconfiguration capabilities of Chinese enterprises can be transferred to other developed and developing markets, including Belt and Road Initiative countries.
Heterotic strings on (K3 × T2)/ℤ3 and their dual Calabi-Yau threefolds
Authors: Banlaki Andreas , Chattopadhyaya Aradhita , Kidambi Abhiram , Schimannek Thorsten , Schimpf Maria
Published: May 2020

Abstract

In this paper we study compactifications of the

$$ \mathcal{N} $$

N

= 2 heterotic E
8
× E
8 string on (K3 × T
2)/ℤ3 with various gauge backgrounds and calculate the topological couplings in the effective supergravity action that arise from one-loop amplitudes. We then identify candidates for dual type IIA compactifications on Calabi-Yau threefolds and compare the heterotic results with the corresponding topological string amplitudes. We find that the dual Calabi-Yau geometries are K3 fibrations that are also genus one fibered with three- sections. Moreover, we show that the intersection form on the polarization lattice of the K3 fibration has to be three times the intersection form on the Narain lattice Γ1,1.
Towards higher-spin AdS2/CFT1 holography
Authors: Alkalaev Konstantin , Bekaert Xavier
Published: May 2020

Abstract

We aim at formulating a higher-spin gravity theory around AdS2 relevant for holography. As a first step, we investigate its kinematics by identifying the low-dimensional cousins of the standard higher-dimensional structures in higher-spin gravity such as the singleton, the higher-spin symmetry algebra, the higher-rank gauge and matter fields, etc. In particular, the higher-spin algebra is given here by [λ] and parameterized by a real parameter λ. The singleton is defined to be a Verma module of the AdS2 isometry subalgebra so (2, 1) ⊂ [λ] with conformal weight

$$ \Delta =\frac{1\pm \lambda }{2}. $$

Δ
=

1
±
λ

2

.

On the one hand, the spectrum of local modes is determined by the Flato-Fronsdal theorem for the tensor product of two such singletons. It is given by an infinite tower of massive scalar fields in AdS2 with ascending masses expressed in terms of λ. On the other hand, the higher-spin fields arising through the gauging of [λ] algebra do not propagate local degrees of freedom. Our analysis of the spectrum suggests that AdS2 higher-spin gravity is a theory of an infinite collection of massive scalars with fine-tuned masses, interacting with infinitely many topological gauge fields. Finally, we discuss the holographic CFT1 duals of the kinematical structures identified in the bulk.
The role of bladder instillation in the treatment of bladder pain syndrome: Is intravesical treatment an effective option for patients with bladder pain as well as LUTS?
Authors: Digesu Giuseppe Alessandro , Tailor Visha , Bhide Alka A. , Khullar Vik
Published: May 2020

The aetiology of bladder pain syndrome/interstitial cystitis is still unknown. Numerous mechanisms have been proposed and treatments targeting various aspects of these are used. This review looks at the existing evidence on bladder instillations and whether they could be used in the treatment of lower urinary tract symptoms as well.
Comparison of Clinical Outcomes Between Surgical Gastrostomy and Percutaneous Endoscopic Gastrostomy with Introducer Technique in Patients with Upper Aerodigestive Malignancies: A Single‐Center Analysis
Authors: Chang Arunchai , Watcharamon Chomduan , Rattanasupa Attapon , Thongsonkleeb Kittikarn , Chowdok Bunlue , Khaimook Araya , Ovartlarnporn Bancha , Prachayakul Varayu
Published: May 2020

Background

Conventional percutaneous endoscopic gastrostomy (PEG) in patients with upper aerodigestive malignancies inevitably carries a risk of stomal metastasis that could be avoided by the direct insertion of the gastrostomy tube through the abdomen. This study compared the efficacy and safety between surgical gastrostomy (SG) and Introducer PEG in patients with upper aerodigestive malignancies.

Methods

We retrospectively reviewed patients with upper aerodigestive malignancies undergoing SG or Introducer PEG. Procedure data, postprocedural clinical outcomes and 30‐day mortality were assessed.

Results

In total, 99 patients were feasible to analysis: 53 were in the SG group, and 46 were in the Introducer PEG group. The SG group had a higher incidence of (in‐hospital) major complications [28.3% VS 4.3%, p = 0.002], a longer procedure duration [52.02 ± 21.30 VS 21.46 ± 8.22 min, p < 0.001], higher pain scores at 24 h [median (interquartile range, IQR); 5(3–8) VS 1(0–5), p < 0.001] and longer length of hospitalization (LOH) [median (IQR); 5(4–6) days VS 3(2–4) days, p < 0.001)]. In‐hospital (3.8% VS 0%, p = 0.493) and 30‐day mortality (17.0% VS 13.0%, p = 0.586) were not different between the two groups. In univariate analysis, high BMI, anemia (hemoglobin <11 g/dL), normal nutritional status (serum albumin >3 g/dL) and procedural type were found to be predicting factors for complications. Procedural type (Introducer PEG) was an independent factor for major complications in multivariate analysis [OR = 0.12, 95% CI 0.02–0.61, p= 0.011].

Conclusions

In patients with upper aerodigestive malignancies, Introducer PEG was associated with lower rate of (in‐hospital) major complications, faster operative time, lower pain scores and shorter LOH.

Clinical trials registry number

TCTR20181220004
Development and Pilot Test of a Virtual Reality Respiratory Biofeedback Approach
Authors: Blum Johannes , Rockstroh Christoph , Göritz Anja S.
Published: May 2020

Breathing exercises with biofeedback have benefits over breathing exercises without biofeedback. However, the traditional measurement of respiratory signals that is required as part of feeding back the breath incurs high cost and effort. We propose a novel virtual reality (VR) based approach to respiratory biofeedback that utilizes the positionally tracked hand controllers integrated into modern VR systems to capture and feedback the respiration-induced abdominal movements. In a randomized controlled laboratory study, we investigated the feasibility and efficacy of the developed biofeedback algorithm. In total, 72 participants performed a short breathing exercise in VR with or without respiratory biofeedback. The feedback integration resulted in a satisfactory user experience, a heightened breath awareness, a greater focus on slow diaphragmatic breathing and an increased respiratory sinus arrhythmia. This evidences that the novel biofeedback approach is low-cost, unobtrusive, usable and effective in increasing breath awareness and promoting slow diaphragmatic breathing in the context of VR-based breathing exercises. Future studies need to investigate the broader applicability and long-term effects.
Entrepreneurial orientation and new venture resource acquisition: why context matters
Authors: Yin Miaomiao , Hughes Mathew , Hu Qilin
Published: May 2020

Resource acquisition is vital for new venture survival and growth. However, surprisingly little is known about how the entrepreneurial orientation (EO) of the new venture affects its resource acquisition. Drawing on the resource-based view of the firm, we articulate a theory and treatment of EO that address this oversight and remedy for the routine absence of context among studies of EO. Accounting for the simultaneous effect of environmental dynamism and an opportunistic orientation (OO), a tendency among Chinese new ventures to imitate technology and profit through market information asymmetry, as important contextual variables reflecting the Chinese business context, we provide insights on the contingency effects of contextual variables. Results from a quantitative study of 361 Chinese new ventures show that EO positively influences resource acquisition. However, this relationship is context sensitive. In a low dynamic environment, OO negatively moderates this relationship. However, in a highly dynamic environment, OO exhibits no effect on the relationship between EO and new venture resource acquisition. Our results contribute to a resource-based theory of EO and reveal its context sensitivity. Our study is a step in moving the scholarship of EO forward and away from the performance debate towards greater predictive accuracy of EO and its systems of effects.
Rapid depletion of dissolved organic sulphur (DOS) in freshwaters
Authors: Brailsford F. L. , Glanville H. C. , Wang D. , Golyshin P. N. , Johnes P. J. , Yates C. A. , Jones D. L.
Published: May 2020

Sulphur (S) is a key macronutrient for all organisms, with similar cellular requirements to that of phosphorus (P). Studies of S cycling have often focused on the inorganic fraction, however, there is strong evidence to suggest that freshwater microorganisms may also access dissolved organic S (DOS) compounds (e.g. S-containing amino acids). The aim of this study was to compare the relative concentration and depletion rates of organic 35S-labelled amino acids (cysteine, methionine) with inorganic S (Na235SO4) in oligotrophic versus mesotrophic river waters draining from low nutrient input and moderate nutrient input land uses respectively. Our results showed that inorganic SO42− was present in the water column at much higher concentrations than free amino acids. In contrast to SO42−, however, cysteine and methionine were both rapidly depleted from the mesotrophic and oligotrophic waters with a halving time < 1 h. Only a small proportion of the DOS removed from solution was mineralized and excreted as SO42− (< 16% of the total taken up) suggesting that the DOS could be satisfying a demand for carbon (C) and S. In conclusion, even though inorganic S was abundant in freshwater, it appears that the aquatic communities retained the capacity to take up and assimilate DOS.
Seasonal variation in estuarine phytoplankton viability and its relationship with carbon dynamics in the Baltic Sea
Authors: Elovaara Samu , Degerlund Maria , Franklin Daniel J. , Kaartokallio Hermanni , Tamelander Tobias
Published: May 2020

Cell death drives the magnitude and community composition of phytoplankton and can result in the conversion of particulate organic carbon to dissolved organic carbon (DOC), thereby affecting carbon cycling in the aquatic food web. We used a membrane integrity probe (Sytox Green) to study the seasonal variation in the percentage of viable cells in the phytoplankton population in an estuary in the northern Baltic Sea for 21 months. The associated dissolved and particulate organic matter concentrations were also studied. The viable fraction of phytoplankton cells varied from < 20% to almost 100%, with an average of 62%. Viability was highest when a single phytoplankton group (diatoms or dinoflagellates) dominated the community. Viability of sinking phytoplankton cells, including some motile species, was in general as high as in surface water. Changes in viability were not closely related to nutrient concentrations, virus-like particle abundance, seawater temperature or salinity. There was a weak but significant negative correlation between viability and DOC, although at this location, the DOC pool was mainly influenced by the inflow of riverine water. This study demonstrates that cell viability, and its relationship with carbon export, is highly variable in the complex microbial populations common within estuarine and coastal marine ecosystems.
What goes around, comes around? Access and allocation problems in Global North–South waste trade
Authors: Cotta Benedetta
Published: May 2020

Infamous cases of toxic waste trade and research on its health and environmental implications have made the global waste trade a prominent environmental and social justice issue. Recently, such trade has shifted towards extracting resources from waste as recyclable components and used goods which could create income-generating opportunities and reduce the environmental burdens of waste trade from Global North to Global South countries. Nevertheless, studies highlight persistent problems in the access to these resources and allocation of responsibilities, risks and burdens from processing and disposal of traded waste in Global South countries. This article aims to contribute to the lessons learnt on access and allocation with respect to waste trade by focusing on issues of equity, fairness and distributive justice. Two cases are analysed: trade in discarded electronic and electric equipment (EEE) between the EU and Africa and trade in plastic materials between the UK and China. This study shows that exports of used EEE and recyclable plastic materials exacerbate the environmental burdens of Global South countries while also exporting new environmental risks and social burdens. At the same time, new demands for justice have emerged from Global South countries through waste ship back initiatives, and new international measures have also been adopted. While the access and allocation lens enabled the identification of persistent problems in Global North–South waste trade, directing future Earth System Governance research to the demands emerging from the Global South countries could offer insights into how to better address these problems and deal with growing global inequalities.
Deterministic global optimization of steam cycles using the IAPWS-IF97 model
Authors: Bongartz Dominik , Najman Jaromił , Mitsos Alexander
Published: May 2020

The IAPWS-IF97 (Wagner et al. (2000) J Eng Gas Turbines Power 122:150) is the state-of-the-art model for the thermodynamic properties of water and steam for industrial applications and is routinely used for simulations of steam power cycles and utility systems. Its use in optimization-based design, however, has been limited because of its complexity. In particular, deterministic global optimization of problems with the IAPWS-IF97 is challenging because general-purpose methods lead to rather weak convex and concave relaxations, thus resulting in slow convergence. Furthermore, the original domains of many functions from the IAPWS-IF97 are nonconvex, while common global solvers construct relaxations over rectangular domains. Outside the original domains, however, many of the functions take very large values that lead to even weaker relaxations. Therefore, we develop tighter relaxations of relevant functions from the IAPWS-IF97 on the basis of an analysis of their monotonicity and convexity properties. We modify the functions outside their original domains to enable tighter relaxations, while we keep them unchanged on their original domains where they have physical meaning. We discuss the benefit of the relaxations for three case studies on the design of bottoming cycles of combined cycle power plants using our open-source deterministic global solver MAiNGO. The derived relaxations result in drastic reductions in computational time compared with McCormick relaxations and can make design problems tractable for global optimization.
The epidemiology of aggressive pituitary tumors (and its challenges)
Authors: Dekkers Olaf M. , Karavitaki Niki , Pereira Alberto M.
Published: May 2020

Pituitary tumors are not rare if prevalence rates from autopsy or radiological series are considered; approximately 0.5% of all pituitary adenomas will come to medical attention. Less than 0.1% of these pituitary adenomas will become malignant, and probably around 0.5% of all detected adenomas will display an aggressive course. However, the exact incidence of both aggressive pituitary adenomas and pituitary carcinomas is unknown, as most data come from series with selected patients, such as surgically treated patients, which is likely not a reflection of all patients with a pituitary adenoma. An aggressive pituitary adenoma is not well-defined; even though an overarching definition, capturing both immunohistochemical and clinical characteristics is probably not waterproof, adoption of a widely accepted definition will be very helpful to harmonize research and establish more reliable epidemiological data.
Farming autonomy: Canadian beef farmers reclaiming the grass through management-intensive grazing practices
Authors: Heiberg Erika J. , Syse Karen Lykke
Published: May 2020

This qualitative study asks farmers in Alberta, Canada,what are their motivations for using a practice in beef production called management-intensive grazing (MIG). By adopting this practice, these farmers engage in strategies of diversification and co-production that increase the autonomy and resilience of their farms. MIG allows farmers to defy conventional agricultural practice and engage in what can be labelled a repeasantization process, a process that contributes to the discussion about conventional farming versus agroecology.
Intraventricular Hemorrhage in a Single Fetus of Dichorionic-Diamniotic Gestation: A Case Report and Review of Literature
Authors: Shelton Jarod , Yasmeh Pauline , Yang Lee
Published: May 2020

Intraventricular hemorrhage (IVH) is a serious complication of prematurity and is of high concern due to the risk of brain injury and in severe cases, death. We report the first case of IVH in a fetus of dichorionic-diamniotic pregnancy that worsened postnatally. Antenatally, magnetic resonance imaging confirmed a large IVH after ventricular abnormalities were detected by prenatal ultrasound (US). At birth, a grade IV IVH diagnosis was made and progressive ventricle dilatation was noted on weekly US. A ventriculoperitoneal shunt was placed and ventricle dilatation was slightly reduced, however, the IVH was essentially unchanged. The infant was discharged in stable condition at 12-weeks-old and chronic neurological dysfunction is expected. IVH is seen in complicated births of prematurity and antenatal US can inform an examiner if fetal IVH is present. It is important to identify IVH and provide immediate intervention to prevent disease worsening during the antenatal and postnatal period.
A Superaerophobic Bimetallic Selenides Heterostructure for Efficient Industrial-Level Oxygen Evolution at Ultra-High Current Densities
Authors: Yuan Jiaxin , Cheng Xiaodi , Wang Hanqing , Lei Chaojun , Pardiwala Sameer , Yang Bin , Li Zhongjian , Zhang Qinghua , Lei Lecheng , Wang Shaobin , Hou Yang
Published: May 2020

Cost-effective and stable electrocatalysts with ultra-high current densities for electrochemical oxygen evolution reaction (OER) are critical to the energy crisis and environmental pollution. Herein, we report a superaerophobic three dimensional (3D) heterostructured nanowrinkles of bimetallic selenides consisting of crystalline NiSe2 and NiFe2Se4 grown on NiFe alloy (NiSe2/NiFe2Se4@NiFe) prepared by a thermal selenization procedure. In this unique 3D heterostructure, numerous nanowrinkles of NiSe2/NiFe2Se4 hybrid with a thickness of ~ 100 nm are grown on NiFe alloy in a uniform manner. Profiting by the large active surface area and high electronic conductivity, the superaerophobic NiSe2/NiFe2Se4@NiFe heterostructure exhibits excellent electrocatalytic activity and durability towards OER in alkaline media, outputting the low potentials of 1.53 and 1.54 V to achieve ultra-high current densities of 500 and 1000 mA cm−2, respectively, which is among the most active Ni/Fe-based selenides, and even superior to the benchmark Ir/C catalyst. The in-situ derived FeOOH and NiOOH species from NiSe2/NiFe2Se4@NiFe are deemed to be efficient active sites for OER.
Is the future of leadership development wearable? Exploring self-tracking in leadership programs
Authors: Ruderman Marian N. , Clerkin Cathleen
Published: May 2020

This practice forum explores how the “quantified self movement” can contribute to developing leaders by offering new approaches to assessment and feedback. Often associated with wearable technologies (digital technologies worn on the body), self-tracking sensors and feedback systems help individuals assess how they interface with the world, automatically capturing and monitoring data for learning, growth, and change. The authors make the case that such tools can create ongoing opportunities for learning intrapersonal qualities relevant to leadership. In particular, they offer insights about using self-tracking to manage responses to stress and fatigue and for the delivery of verbal presentations. The exploration also notes concerns about the use of technological devices for development purposes. The authors conclude by offering a summary of six factors to consider before using self-tracking tools for leadership development, and by identifying four aspects of self-tracking approaches that would benefit from more I-O psychologist involvement.
MIGUEL LEÓN-PORTILLA AND ARCHAEOLOGY
Authors: López Luján Leonardo
Published: May 2020

After a long hospital stay, Mexican historian and philosopher Miguel León-Portilla passed away on October 1, 2019, at the age of 93. His prodigious work is known throughout the world because classics such as La filosofía náhuatl (León-Portilla 1956), Visión de los vencidos (León-Portilla 1959), Los antiguos mexicanos a través de sus crónicas y cantares (León-Portilla 1961), Las literaturas precolombinas de México (León-Portilla 1964), Trece poetas del mundo azteca (León-Portilla 1967), and Teatro náhuatl (León-Portilla 1974a), among others, have been published and republished dozens of times in a multitude of languages. Professor William R. Fowler kindly asked me to write an obituary for Ancient Mesoamerica and suggested that I focus my text on the contributions that Dr. León-Portilla made in my field, that is, archaeology. To this end I have decided to offer the readers of this journal an English translation of a brief discourse I presented on February 22, 2016 (Figure 1), in the context of a tribute paid to “Don Miguel” on the occasion of his ninetieth birthday, which was organized by the Universidad Nacional Autónoma de México.
Operation Navajeevan: A Public-Private Partnership Model for Disaster Relief in Kozhikode, India
Authors: Haris Sonia , Poovathumparambil Venugopalan , Anaswara Naveen , Noll Samantha , Ghatak-Roy Aditi , Dreyer Nicholas , Naik Nehal , Douglass Katherine , Blanchard Janice , Davey Kevin
Published: May 2020

Introduction:

In August 2018, India’s southern state of Kerala experienced its worst flooding in over a century. This report describes the relief efforts in Kozhikode, a coastal region of Kerala, where Operation Navajeevan was initiated.

Sources:

Data were collected from a centralized database at the command center in the District Medical Office as well as first-hand accounts from providers who participated in the relief effort.

Observations:

From August 15 through September 8, 2018, 36,846 flood victims were seen at 280 relief camps. The most common cause for presentation was exacerbation of an on-going chronic medical condition (18,490; 50.2%). Other common presentations included acute respiratory infection (7,451; 20.2%), traumatic injuries (3,736; 10.4%), and psychiatric illness (5,327; 14.5%).

Analysis:

The prevalence of chronic disease exacerbation as the primary presentation during Operation Navajeevan represents an epidemiologic shift in disaster relief in India. It is foreseeable that as access to health care improves in low- and middle-income countries (LMICs), and climate change increases the prevalence of extreme weather events around the world, that this trend will continue.
The RhHB1/RhLOX4 module affects the dehydration tolerance of rose flowers (Rosa hybrida) by fine-tuning jasmonic acid levels
Authors: Fan Youwei , Liu Jitao , Zou Jing , Zhang Xiangyu , Jiang Liwei , Liu Kun , Lü Peitao , Gao Junping , Zhang Changqing
Published: May 2020

Phytohormones are key factors in plant responsiveness to abiotic and biotic stresses, and maintaining hormone homeostasis is critically important during stress responses. Cut rose (Rosa hybrida) flowers experience dehydration stress during postharvest handling, and jasmonic acid (JA) levels change as a result of this stress. However, how JA is involved in dehydration tolerance remains unclear. We investigated the functions of the JA- and dehydration-inducedRhHB1gene, which encodes a homeodomain-leucine zipper I γ-clade transcription factor, in rose flowers. SilencingRhHB1decreased petal dehydration tolerance and resulted in a persistent increase in JA-Ile content and reduced dehydration tolerance. An elevated JA-Ile level had a detrimental effect on rose petal dehydration tolerance. RhHB1 was shown to lower the transient induction of JA-Ile accumulation in response to dehydration. In addition to transcriptomic data, we obtained evidence that RhHB1 suppresses the expression of the lipoxygenase 4 (RhLOX4) gene by directly binding to its promoter both in vivo and in vitro. We propose that increased JA-Ile levels weaken the capacity for osmotic adjustment in petal cells, resulting in reduced dehydration tolerance. In conclusion, a JA feedback loop mediated by anRhHB1/RhLOX4regulatory module provides dehydration tolerance by fine-tuning bioactive JA levels in dehydrated flowers.
Silicon incorporation in polymethine dyes
Authors: Pengshung Monica , Neal Patrick , Atallah Timothy L. , Kwon Junho , Caram Justin R. , Lopez Steven A. , Sletten Ellen M.
Published: May 2020

Incorporation of silicon into heterocycles for polymethine dyes can impart red-shifts of up to 100 nm, while also enhancing photostability up to 10-fold, resulting in photostable fluorophores with emission above 900 nm.
Carbonylative synthesis of heterocycles involving diverse CO surrogates
Authors: Chen Zhengkai , Wang Le-Cheng , Wu Xiao-Feng
Published: May 2020

Recent advances in the carbonylative synthesis of heterocycles by using diverse CO surrogates as sources of CO are summarized and discussed.
Ultra-efficient and stable heterogeneous iron-based Fenton nanocatalysts for degrading organic dyes at neutral pH via a chelating effect under nanoconfinement
Authors: Lin Jiayou , Chen Sheng , Xiao Hongyan , Zhang Jiawen , Lan Jianwu , Yan Bin , Zeng Hongbo
Published: May 2020

An ultra-efficient and stable heterogeneous iron-based Fenton nanocatalyst has been developed for degrading organic dyes at neutral pH via a chelating effect under nanoconfinement.
Alloxan under pressure–squeezing an extremely dense molecular crystal structure
Authors: Funnell Nicholas P. , Bull Craig L. , Ridley Christopher J. , Parsons Simon , Tellam James P.
Published: May 2020

At high pressure, the crystal structure of alloxan reaches an abnormally large density for a C, H, N, O-containing organic.
Tunable relativistic quasiparticle electronic and excitonic behavior of the FAPb(I1−xBrx)3 alloy
Authors: Muhammad Zeeshan , Liu Peitao , Ahmad Rashid , Jalali Asadabadi Saeid , Franchini Cesare , Ahmad Iftikhar
Published: May 2020

The quasiparticle and excitonic properties of mixed FAPb(I1−xBrx)3 0 ≤ x ≤ 1 alloys are studied. We show that Br-doping provides an efficient and controllable way to tune the band gap and optical properties, beneficial for material design of high performance tandem solar cells.
The impact of reaction rate on the formation of flow-driven confined precipitate patterns
Authors: Balog Edina , Papp Paszkál , Tóth Ágota , Horváth Dezső , Schuszter Gábor
Published: May 2020

The evolution of different confined precipitation patterns is determined by the ratio of the chemical and hydrodynamic time scales.
Mixed uranyl and neptunyl cation–cation interaction-driven clusters: structures, energetic stability, and nuclear quadrupole interactions
Authors: Tecmer Paweł , Schindler Frank , Leszczyk Aleksandra , Boguslawski Katharina
Published: May 2020

We present a quantum-chemical study of mixed CCI clusters, their structures, energetic stability, and nuclear quadrupole interactions.
Tailoring the protonic conductivity of porous yttria-stabilized zirconia thin films by surface modification
Authors: Celik Erdogan , Negi Rajendra S. , Bastianello Michele , Boll Dominic , Mazilkin Andrey , Brezesinski Torsten , Elm Matthias T.
Published: May 2020

Porous yttria-stabilized zirconia (YSZ) thin films were prepared by pulsed laser deposition to investigate the influence of specific surface area on the electrical and protonic transport properties.
Decoupling nucleation from crystal-growth for the synthesis of nanocrystalline zeolites
Authors: Zhang Guanqun , Fan Yaqi , Huang Ju , Wang Lijin , Yang Chengguang , Lyu Meng , Liu Haiming , Ma Yanhang
Published: May 2020

A facile synthesis strategy for nanosized zeolites by successfully decoupling nucleation from crystal-growth in a concentrated hydrated gel (HG) system.
Scalable synthesis and polymerisation of a β-angelica lactone derived monomer
Authors: Dell'Acqua Andrea , Stadler Bernhard M. , Kirchhecker Sarah , Tin Sergey , de Vries Johannes G.
Published: May 2020

A new bio-based norbornene polymer was prepared starting from β-angelica lactone, prepared in a sustainable and scalable manner from the platform chemical levulinic acid. The new material displays transparency comparable to petrochemical-derived polynorbornene.
Photochemical strategies for C–N bond formation via metal catalyst-free (hetero) aryl C(sp2)–H functionalization
Authors: Kang Qing-Qing , Wu Wenfeng , Li Qiang , Wei Wen-Ting
Published: May 2020

The development of efficient and mild methods to assemble C–N bonds represents an important and appealing goal in modern synthetic chemistry.
Acoustic separation of living and dead cells using high density medium
Authors: Olofsson Karl , Hammarström Björn , Wiklund Martin
Published: May 2020

A novel, simple and robust route for binary separation of viable and dead cells using a density modified medium which takes advantage of the compromised cell membrane of dead cells.
A laccase-catalysed tyrosine click reaction
Authors: Sato Shinichi , Nakane Keita , Nakamura Hiroyuki
Published: May 2020

The tyrosine click reaction of peptides/proteins with the tyrosine modification reagent, N-methyl luminol, was catalysed by a laccase in the presence of molecular oxygen (O2) at 37 °C.
Metal–metal cooperative bond activation by heterobimetallic alkyl, aryl, and acetylide PtII/CuIcomplexes
Authors: Deolka Shubham , Rivada-Wheelaghan Orestes , Aristizábal Sandra L. , Fayzullin Robert R. , Pal Shrinwantu , Nozaki Kyoko , Khaskin Eugene , Khusnutdinova Julia R.
Published: May 2020

The selective formation of heterobimetallic PtII/CuIcomplexes demonstrates how facile bond activation processes can be achieved by altering the reactivity of common organoplatinum compounds through their interaction with another metal center.
Transmit power minimisation for full‐duplex two‐way relaying systems with asymmetric packet‐rates and quality‐of‐service requirements
Authors: Qian Chong , Ji Xiaodong , Cao Zhanghua , Li Wenhua
Published: May 2020

This study solves the transmit power minimisation problem subject to a target quality‐of‐service constraint of a full‐duplex (FD) two‐way decode‐and‐forward relaying system with asymmetric packet‐rates, where the two‐way relaying system can operate in two different styles, i.e. half‐duplex sources with full‐duplex relaying (HDS‐FDR) and full‐duplex sources with full‐duplex relaying (FDS‐FDR) styles. For the FDS‐FDR style, the relay node can use two strategies to handle the received signals from the sources, namely, physical‐layer network coding (PNC) and physical‐layer superposition coding (PSC), both of which are referred to as FDS‐FDR‐PNC and FDS‐FDR‐PSC styles, respectively. By transforming the transmit power minimisation problem into a two‐stage problem, optimum power control (OPC) techniques are developed for the HDS‐FDR, FDS‐FDR‐PNC and FDS‐FDR‐PSC styles, respectively, giving closed‐form solutions for individual transmit power at the relay and the sources. Computer simulations are conducted and the results validate the proposed OPC techniques. It is shown that the FDS‐FDR‐PNC style performs best in terms of energy saving when the two sources' packet‐rates are moderately asymmetric or symmetric. For the case that the packet‐rates are strongly asymmetric, the FDS‐FDR‐PSC style can save more energy than the other two styles.
Consumer flexibility driven energy management for air conditioning systems in a building community
Authors: Alic Oguzkagan , Filik Ümmühan Başaran
Published: May 2020

Demand response (DR) programmes are considered as elegant solutions to supply the permanent growth in energy demand. The residential building sector accounts for a significant amount of this growth. By means of their elastic behaviour in energy usage, residential consumers can manage their energy consumption for cost savings by participating in DR programmes. A substantial part of energy consumption in a residence is due to heating, ventilation, and air conditioning (HVAC) loads. As an HVAC load, air conditioners have high ownership rates and are energy‐intensive appliances. This study, therefore, presents a cost and comfort effective energy management scheme based on consumer flexibilities for air conditioning systems in a residential building community on DR purposes. Three different pricing mechanisms under two different scenarios are employed to analyse the benefits and effectiveness of the proposed scheme. Furthermore, a strategy is performed to fairly allocate the cost savings of the community among consumers. The obtained results verified the efficacy of the proposed scheme in providing cost‐saving, peak load reduction, and desired thermal convenience.
Low‐complexity inductance estimation for switched‐mode power converters using peak‐current mode control
Authors: Michal Vratislav , Nicolò Zilio , Matteo Agostinelli
Published: May 2020

This study describes a technique for automated and accurate inductance estimation in synchronous DC–DC buck and boost converters. The method of inductor value estimation is based on the dependence of the steady‐state output voltage on the inductance value, in the case of a fixed inductor peak current. The measurement algorithm yields effective inductance value, and is aimed to be executed once during the start‐up procedure under light load current condition. As the measurement is performed during the start‐up sequence with low‐load current, a dedicated current sensor with high accuracy can be employed, allowing to target high measurement accuracy in the range of ±5%. The presented technique is developed to enable the automated design of a digital controller for general purpose DC–DC converter but can be used in different applications such as analogue feedback‐loop adjustment or improving the digital current estimator accuracy.
Stability analysis for direct‐drive permanent magnet synchronous generator based wind farm integration system considering wind speed
Authors: Zou Xiaoming , Du Xiong , Tai Heng‐Ming
Published: May 2020

The interaction between wind farm and power grid may cause the stability issue in the wind farm integration system. Practically, the integration system contains many collector feeders, and one feeder connects a large number of wind turbine generators. Moreover, frequency coupling effect is introduced in all parts of the wind farm system due to the asymmetrical controller of the wind turbine converter. So, it is complicated to analyse the stability of the whole integration system. This study proposes the modular admittance model for wind farm, which is easy to expand for modelling and analysis of the whole integration system. In addition, the operation condition of wind turbine generators in wind farm varies with the prevailing wind speed. The system stability may alter constantly according to the wind speed. How to effectively evaluate the system stability in the entire wind speed operation space is also a challenge. Thus, for wind farm system, this study develops an approach with two‐variable admittance model and criterion based on magnitude and phase contours plot to overcome this problem. The proposed admittance model and stability analysis approach are verified by simulation.
Influence of rotational inertia on the runner radial forces of a model pump‐turbine running away through the S‐shaped characteristic region
Authors: Zhang Xiaoxi , Cheng Yongguang , Yang Zhiyan , Chen Qiuhua , Liu Demin
Published: May 2020

To enhance the power grid's stability and safety, pumped‐storage power stations (PSPSs) have to keep themselves stable and safe strictly. However, instabilities happen frequently in some PSPSs due to the S‐shaped characteristics of pump‐turbines. When the operating point goes through the S‐shaped region, intensive radial forces on the runner could cause shaft swing of the turbine‐generator unit. In this study, the runaway transient scenarios of a pump‐turbine in a model PSPS were simulated by using a one‐dimensional and three‐dimensional coupled computational fluid dynamics model, and the influence of the unit rotational inertia on the runner radial forces was investigated. The results show that when the pump‐turbine runs in the S‐shaped region, large rotational inertia is easier than a small one to induce abrupt increases in runner radial forces. The reason is that large rotational inertia gives slower changes in rotational speed and discharge, providing enough time to generate unstable and uneven flow patterns in the pump‐turbine. This indicates that apart from the running away region in the characteristics plane, the running away duration is also essential for the transient instability of a pump‐turbine. The finding is different from the traditional understandings and should be considered when selects the rotational inertia of a pump‐turbine unit.
Evaluation of wind turbine power outputs with and without uncertainties in input wind speed and wind direction data
Authors: Zou M. , Fang D. , Djokic S.Z. , Di Giorgio V. , Langella R. , Testa A.
Published: May 2020

This paper analyses importance of including wind direction (WD) as an additional explanatory variable to the wind speed (WS) for evaluating uncertainty in wind turbine (WT) power output (P out). Using available measurements of an actual WT, the paper compares a ‘two‐dimensional’ (2D) P out ‐WS model with a ‘three‐dimensional’ (3D) P out ‐WS‐WD model for two general cases: (a) for the specific input WS and WD values (i.e. WS and WD without uncertainties), and (b) for the forecasted input WS and WD values (i.e. WS and WD with uncertainties). In paper, 2D and 3D Gaussian mixture Copula model and vine Copula framework are combined with 2D and 3D Markov chain models, which are used to forecast input WS and WD data with uncertainties. The obtained results show that inclusion of WD will provide noticeable improvement for models with no uncertainties in input WS and WD data, while in the case of forecasted WS and WD data with uncertainties, WS is a much stronger contributor to the total WT P out uncertainty than WD.
Design of intelligent and efficient water and electricity cogeneration equipment
Authors: Zhang Haomin , Wu Yuzhe
Published: May 2020

The solar steam generation system studied in this project is mainly composed of a double-layered structure. The upper layer is a nano-fluid material with a light absorber, and the lower layer is an insulating material with two-dimensional or three-dimensional water transport channels. It is hydrophilic to utilize capillary forces and promote Fluid flows to the hot zone, and interconnected pores are used for fluid inflow and outflow to the structure. The device embeds a semiconductor temperature difference power generation sheet in the lower layer, the upper surface is in contact with the photothermal layer, and the lower surface is in contact with the bulk water. The formation of a temperature difference generates an electromotive force, which makes the energy utilization efficiency higher.
Study on the Combustion Characteristics and Kinetic Parameters of the Blended Coal Treated with Different Grinding Methods
Authors: Boping Wang , Liang Liu , Xun Wang , Xunzhou Fang , Qinjia Hou , Zenghui Liu , Kailun Wang
Published: May 2020

The presented investigation focused on the combustion characteristics and kinetic parameters of the coals blended using different grinding methods (separated and mixed grinding), via Thermogravimetric analyser. According to the thermogravimetric experiments, with the increase of the proportion of Yangcheng coal, the combustion characteristics of the coal treated with the mixed grinding method are increasingly better than those of the coal treated with the separated grinding method (under the same mixing ratio). Additionally, the methods of Coats-Redfern were applied to calculate kinetic parameters, which indicated that when the proportion of Yangcheng coal is 30%, the activation energy values of the coal treated with two grinding methods are similar; when the proportion of Yangcheng coal is below 30%, the activation energy values of coal treated with the separated grinding method is lower than that of the coal treated with the mixed grinding method; when the proportion of Yangcheng coal is above 30%, the activation energy values of the coal treated with the mixed grinding method is lower than that of the coal treated with the separated grinding method.
Research on Key Technologies of High-yield and High-efficiency Production in Coal Enterprises
Authors: Na Liu
Published: May 2020

According to the production characteristics of coal enterprises in China, this paper defines the essential connotations and main characteristics of high-yield and high-efficiency coal enterprises from the perspectives of high quality and high efficiency. On this basis, this paper analyzes the key elements and points to achieve high-yield and high-efficiency production in coal enterprises, and then constructs the key technology system of high-yield and high-efficiency production in coal enterprises in China, so as to provide reference for the improvement of the overall production level in coal enterprises.
Market clearing model of distribution network-side integrated energy system
Authors: Yang Dongmei , Sun Yong , Li Baoju , Zhang Xiaochen , Li Pengfei , Liu Dunnan
Published: May 2020

In an electric-gas integrated energy system that considers the coupling conditions between systems, there is energy transaction between the systems. So the node energy price setting method and market clearing strategy of the coupled system are worth studying. First of all, this paper establishes a market clearing model for electricity / gas subsystems and a method for solving node energy prices. Then, a market clearing model of the electrical coupling system is established based on this. Finally, an example to verify the effectiveness of the nodal energy price formulation method and the market clearing model is given.
Experimental study on the performance of flat air collector with reticulated endothermic body
Authors: Hong Liang , Zhiguo Han , Jing Wang , Kunjiang Duli , Zhiyong Li
Published: May 2020

Because the flat air collector is simple in structure, reliable in operation, and resistant to cold and frost, it is more suitable for applications such as building heating. This paper presents a flat air collector with a mesh heat sink, and analyzes the effects of air flow, temperature difference between inlet and outlet, and wire mesh density on the heat collection efficiency of the collector. The results show that when the pore density is fixed, the heat collection efficiency increases with the increase of air flow rate, which is 10% higher than that of natural convection when the air flow rate is maximum; when the air flow rate is fixed, the heat collection efficiency increases with the increase of the pore density and the temperature difference between the inlet and outlet, which can be increased by 10% -20%.
Analysis and Discussions on the Nonuniformity Problem of SCR Denitration Equipment NOx Concentration Distribution in a 600MW Coal-fired Unit
Authors: Ketao Xu , Yongbing He , Yang Zhang
Published: May 2020

Combining with an engineering example, from the aspects of SCR inlet NOx concentration distribution, flue gas velocity uniformity, ammonia injection valve opening, ash deposit, abrasion and flue arrangement, the uniformity problem of SCR denitration equipment outlet NOx concentration distribution is analyzed and discussed in a 660MW coal-fired unit. The results show that the uneven distribution of NOx concentration is caused by the combined action of many factors. In the cause analysis and solution formulation, the influence factors need be overall consideration. By adjusting the ammonia injection valve opening, the uniformity of SCR outlet NOx concentration increases by about 30%, the performance of SCR denitration equipment is obviously improved. At the same time, rationalization proposals and solution measures for the improvement of outlet concentration uniformity are given in order to ensure the safe and stable operation of denitration equipment.
Study on the influence factors of energy efficiency ratio of low temperature air source heat pump
Authors: Hong-wen Jin , Lei Yang , Bing-qi Song , Yong-liang Wu , Yan-peng Zhang
Published: May 2020

In this paper, through the experimental study of two heating seasons, it is found that the heat pump installation position and orientation, circulating pump work/frequency conversion, frosting conditions, etc. have a greater impact on the heat pump unit energy efficiency ratio. According to the actual operation data and theoretical derivation, the analysis shows that the energy efficiency ratio increases by 2.4% when the installation position and orientation increase the air temperature by 1K. The circulating water pump can save 78% of the power consumption in the period by changing the power frequency to frequency conversion. The frosting condition diagram can make a reasonable configuration and operation prediction for the heat pump system.