bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent Progress in Utilization of Functionalized Organometallic Reagents in Cross Coupling Reactions and Nucleophilic Additions
Authors: Dong Zhi-Bing , Chen Jin-Quan
Published: November 2020

Organometallic compounds have become increasingly important in organic synthesis because of their high chemoselectivity and excellent reactivity. Recently, a variety of organometallic reagents were found to facilitate transition-metal-catalyzed cross-coupling reactions and nucleophilic addition reactions. Here, we have summarized the latest progress in cross-coupling reactions and in nucleophilic addition reactions with functionalized organometallic reagents present to illustrate their application value. Due to the tremendous contribution made by the Knochel group towards the development of novel organometallic reagents, this review draws extensively from their work in this area in recent years.

Introduction

1 Transition-Metal-Catalyzed Cross Couplings Involving Organo­zinc Reagents

2 Transition-Metal-Catalyzed Cross Couplings Involving Organomagnesium Reagents

3 Transition-Metal-Free Cross Couplings Involving Zn and Mg ­Organometallic Reagents

4 Nucleophilic Additions Involving Zn and Mg Organometallic Reagents

5 Cross-Coupling Reactions or Nucleophilic Additions Involving Mn, Al-, La-, Li-, Sm- and In-Organometallics

6 Conclusion
A Novel Microsurgical Suturing Pilot Course for Ophthalmology Residents Based on Kern's Model for Curriculum Development
Authors: Roginiel Aliya C. , Teng Christopher C. , Chow Jessica H.
Published: November 2020

Background Sutureless ophthalmic procedures are becoming more commonplace, reducing opportunities for ophthalmology residents to learn microsurgical suturing techniques. There is no standard curriculum in place to address this gap in clinical training among ophthalmology residency programs.

Objective The aim of this study was to design, implement, and evaluate a preliminary microsurgical suturing curriculum for ophthalmology residents using Kern's six-step approach for curriculum development as a guideline, and the principles of distributed practice and guided, self-directed practice.

Methods We designed a faculty-led teaching session on fundamental microsurgical suturing techniques for all 15 ophthalmology residents from Yale University over one academic year. Suturing skills were evaluated, followed by a guided teaching session, 30 days of self-directed practice time, and a re-evaluation of skills. The residents were evaluated through a written knowledge assessment and practical skills assessment. The residents also evaluated their skill level before and after the teaching session and practice period through written Likert-scale surveys. Data were evaluated in Excel using descriptive statistics and the paired t-test.

Results After the session, postgraduate year 2 (PGY-2) residents felt more confident in recognition and use of surgical instruments (p < 0.01). PGY-3 residents felt less confident in their knowledge of microsurgical suturing after the session (p = 0.02). PGY-4 residents felt they were better able to identify different suture types after the session (p = 0.02). All residents improved on the written knowledge assessment (p < 0.001) and in all categories of the practical skills assessment (p < 0.001).

Conclusions Implementation of a faculty-led microsurgical suturing training session, followed by 1-month of practice time, significantly improved residents' knowledge and practical application of various microsurgical suturing techniques that are necessary for performing common ophthalmic procedures.
Accuracy of an Electronic Health Record Patient Linkage Module Evaluated between Neighboring Academic Health Care Centers
Authors: Ross Mindy K. , Sanz Javier , Tep Brian , Follett Rob , Soohoo Spencer L. , Bell Douglas S.
Published: November 2020

Background Patients often seek medical treatment among different health care organizations, which can lead to redundant tests and treatments. One electronic health record (EHR) platform, Epic Systems, uses a patient linkage tool called Care Everywhere (CE), to match patients across institutions. To the extent that such linkages accurately identify shared patients across organizations, they would hold potential for improving care.

Objective This study aimed to understand how accurate the CE tool with default settings is to identify identical patients between two neighboring academic health care systems in Southern California, The University of California Los Angeles (UCLA) and Cedars-Sinai Medical Center.

Methods We studied CE patient linkage queries received at UCLA from Cedars-Sinai between November 1, 2016, and April 30, 2017. We constructed datasets comprised of linkages (“successful” queries), as well as nonlinkages (“unsuccessful” queries) during this time period. To identify false positive linkages, we screened the “successful” linkages for potential errors and then manually reviewed all that screened positive. To identify false-negative linkages, we applied our own patient matching algorithm to the “unsuccessful” queries and then manually reviewed a sample to identify missed patient linkages.

Results During the 6-month study period, Cedars-Sinai attempted to link 181,567 unique patient identities to records at UCLA. CE made 22,923 “successful” linkages and returned 158,644 “unsuccessful” queries among these patients. Manual review of the screened “successful” linkages between the two institutions determined there were no false positives. Manual review of a sample of the “unsuccessful” queries (n = 623), demonstrated an extrapolated false-negative rate of 2.97% (95% confidence interval [CI]: 1.6–4.4%).

Conclusion We found that CE provided very reliable patient matching across institutions. The system missed a few linkages, but the false-negative rate was low and there were no false-positive matches over 6 months of use between two nearby institutions.
The Usefulness of HIV-1p24 in Detecting the Presence of HIV Infection in Histopathology Tissue Specimens
Authors: Menkiti Felix Emeka , Ukah Cornelius Ozobia , Adelusola Kayode A. , Ezejiofor Ifeoma Florence
Published: November 2020

Introduction HIV (human immunodeficiency virus)-associated immunodeficiency is the single most important acquired immunodeficiency in humans, underlying several diseases. The presence of HIV infection may be unsuspected or undetected in tissues due to latency or failure of the consulting physician to document it on the requisition form. HIV-1p24 protein is a component of the HIV particle capsid that can be exploited serologically and immunohistochemically to detect the presence of HIV infection. This study aimed to assess the usefulness of HIV-1 p24 immunohistochemistry in detecting the presence of HIV infection in histopathology tissues in a resource-challenged setting.

Materials and Methods HIV-1p24 immunohistochemical expression was evaluated in 59 cases from the archives of both Nnamdi Azikiwe University Teaching Hospital (NAUTH) and Pathocon Specialist Clinic and Research Institute over a 10-year period. Pathology consult forms of all clinically and morphologically suspected cases of Kaposi sarcoma and their blocks were retrieved, recut, and reviewed using hematoxylin and eosin, and then subjected to HIV-1p24 immunohistochemical staining.

Results Of the 59 cases, 38 expressed p24, whereas 21 were negative. Fifteen of the positive cases had no prior documented evidence of HIV infection. Five cases with clinically known statuses, four positive and one negative, were found to be negative and positive, respectively, following HIV-1p24 immunohistochemical staining, probably due to usage of ELISA (enzyme-linked immunosorbent assay) detection kit only and long term antiretroviral therapy. HIV infection was commoner in the third and fourth decades of life.

Conclusion HIV-1p24 is a useful low-cost immunohistochemical marker in detecting the presence of HIV infection in histopathology specimens, even in previously unsuspected cases.
Tricortical Bone Grafting with Limited Midcarpal and Carpometacarpal Fusion for the Treatment of Giant Cell Tumor of the Capitate
Authors: Chalidis Byron E. , Dimitriou Christos G. , Givissis Panagiotis K.
Published: November 2020

Background Giant cell tumor (GCT) of capitate is a rare lesion that is challenging to treat.

Case Description We present a case of a 12-year-old girl suffering from a GCT of the capitate. Wide excision combined with adjuvant treatment including hydrogen peroxide, alcohol, tricortical bone grafting, and limited midcarpal and carpometacarpal fusion achieved good functional result without evidence of tumor recurrence or radiocarpal degeneration at 8 years postoperatively.

Clinical Relevance In this case with long-term follow-up, surgical treatment of capitate GCT with limited midcarpal and carpometacarpal fusion led to a satisfactory outcome despite the alteration of wrist kinematics.
Aneurysmectomy for Crawford’s Type-I Thoracoabdominal Aortic Aneurysm using Gelatin Impregnated Woven Vascular Prosthesis under Mild Hypothermic Extracorporeal Circulation: A Video Presentation
Authors: Chowdhury Ujjwal K. , Singh Sukhjeet , George Niwin , Kapoor Poonam Malhotra , Sharma Srikant , Pandey Niraj Nirmal , Sengupta Sanjoy , Vaswani Prateek
Published: November 2020

Based on the risk of ischemic injury to the spinal cord and the risk of renal failure and mortality, Crawford and colleagues classified thoracoabdominal aortic aneurysms into four extents. Type I thoracoabdominal aortic aneurysms involved the descending thoracic aorta proximal to the level of 6th rib to above the renal arteries; type II extends from the proximal descending thoracic aorta above the level of T6 to below the renal arteries; type III extends from below the level of T6 in the descending aorta and a variable extent in the abdominal aorta; type IV thoracoabdominal aortic aneurysm involved the abdominal aorta without involvement of the descending aorta.
Globalization and future of power relations in the Arabic Middle-East: a case study of Egypt and Libya
Authors: Nikfar Jaseb
Published: November 2020

In the Arab Middle-East, power relations have been conceived of as unequal, unilateral, and imposing. However, globalization has posed challenges to this absolute and authoritarian political order. More specifically, the process of globalization diminishes governments’ domination and absolute power, changes the attitude of subjects and inevitably transforms power relations in the Arab Middle-East. Weakening the control mechanisms and provision of proper facilities and platforms leads eventually to a change in the subjects’ attitudes and growth in their awareness. The present paper aims to study the effects of globalization on power relations in the Arab Middle-East, with a focus on Egypt and Libya. The paper argues and concludes that the change in power relations and political order transformation are inevitable.
How cultural evolution can inform the science of science communication—and vice versa
Authors: Bendixen Theiss
Published: November 2020

Cultural evolution research is the study of how cultural traits (e.g., beliefs and behavioral patterns) stabilize, change and diffuse in populations, and why some cultural traits are more “attractive” (i.e., more likely to spread) than others. As such, cultural evolution is highly relevant for the emerging “science of science communication” (SSC) in that it can help organize and guide the study of science communication efforts aimed at spreading scientifically accurate information and inspiring behavioral change. Here, I synthesize insights and theory from cultural evolution with central findings and concepts within the SSC with the aim of highlighting the inherent, but underexplored, consilience between these two fields. I demonstrate how cultural evolution can serve as an unifying framework for the SSC and how, conversely, science communication can serve as a fertile testing ground for applying, exploring, and advancing cultural evolutionary theory in a real-world setting that matters. Lastly, I highlight merits and limitations of previous applications of cultural evolution to science communication and conclude with some particularly outstanding questions that emerge at the intersection between cultural evolution and science communication research.
Time-dependent taphonomic site loss leads to spatial averaging: implications for archaeological cultures
Authors: Coco Emily , Iovita Radu
Published: November 2020

Archaeologists typically define cultural areas on the basis of similarities between the types of material culture present in sites. The similarity is assessed in order of discovery, with newer sites being evaluated against older ones. Despite evidence for time-dependent site loss due to taphonomy, little attention has been paid to how this impacts archaeological interpretations about the spatial extents of material culture similarity. This paper tests the hypothesis that spatially incomplete data sets result in detection of larger regions of similarity. To avoid assumptions of cultural processes, we apply subsampling algorithms to a naturally occurring, spatially distributed dataset of soil types. We show that there is a negative relationship between the percentage of points used to evaluate similarity across space and the absolute distances to the first minimum in similarity for soil classifications at multiple spatial scales. This negative relationship indicates that incomplete spatial data sets lead to an overestimation of the area over which things are similar. Moreover, the location of the point from which the calculation begins can determine the size of the region of similarity. This has important implications for how we interpret the spatial extent of similarity in material culture over large distances in prehistory.
Optical bioimaging revival may be possible by understanding autofluorescence in animal tissues
Authors: Johnson-Groh Mara
Published: November 2020

An overview of autofluorescence in animal tissues and tutorial for experimentation aims to increase interest in a growing interdisciplinary field.
Insight into thorium dioxide could provide new energy applications
Authors: Johnson-Groh Mara
Published: November 2020

Microscale defects in thorium dioxide were found to have large effects on its thermal transport.
Explaining the efficiency-boosting effects of sodium on CIGS solar cells
Authors: Kim Meeri
Published: November 2020

Even small concentrations of sodium altered the properties of CIGS solar cells, increasing open-circuit voltage, fill factor, hole density, and mobility.
MXenes materials could be used in wearable pressure sensors
Authors: Gasparini Allison
Published: November 2020

Researchers reviewed the properties of MXenes and found these materials have the necessary qualities to be integrated into wearable electronics.
Inductively coupled plasmas could be a low-power alternative for satellite propulsion
Authors: Bandari Anashe
Published: November 2020

Pending improvements in thrust performance, simulations suggest inductively coupled plasma electrothermal thrusters may be suitable for atmospheric electric propulsion systems.
Sub-scaling method is capable of representing full-scale wind turbine dynamics
Authors: Gasparini Allison
Published: November 2020

Researchers developed a method of sub-scaling called Servo-Aero-Gravo-Elastic Scaling to investigate the dynamics of extreme-length wind turbine blades at a fraction of the cost.
Complex interferometry measures spontaneous magnetic fields between lasers and plasmas
Authors: Liebendorfer Adam
Published: November 2020

Coupling interferometry and polarimetry measurements into one snapshot allows researchers to conduct measurements in a multi-frame regime.
A novel versatile instrument for combined studies of persistent luminescence, thermoluminescence, and mechanoluminescence in micro-scale
Authors: Jiang Hailin , Xiong Chenwei , Long Siwei , Ma Decai , Mu Cuiling , Ma Haoze , Li Huashan , Lin Shaopeng , Wang Biao
Published: November 2020

This paper presents a new method for combined measurements of persistent luminescence (PersL), thermoluminescence (TL), and mechanoluminescence (ML) of luminescent materials in the micrometer scale. Both the hardware and software designs have been illustrated in detail, and the experimental procedures to execute the emission map, PersL, TL, and ML measurements have been demonstrated. The PersL, TL, and ML properties of the SrAl2O4:Eu2+, Dy3+ micropowder, as well as the corresponding temperature variable emission spectra, have been measured. The results show good agreement with published investigations, indicating the accomplishment of designed functions. The instrument would be a powerful tool for exploring phosphorescent materials in the micrometer and smaller scales.
Implementation of amplitude–phase analysis of complex interferograms for measurement of spontaneous magnetic fields in laser generated plasma
Authors: Zaraś-Szydłowska A. , Pisarczyk T. , Chodukowski T. , Rusiniak Z. , Dudzak R. , Dostal J. , Kalal M. , Kochetkov Iu. , Krupka M. , Borodziuk S. , Pisarczyk P.
Published: November 2020

Generation of spontaneous magnetic fields (SMFs) is one of the most interesting phenomena accompanying an intense laser–matter interaction. One method of credible SMFs measurements is based on the magneto-optical Faraday effect, which requires simultaneous measurements of an angle of polarization plane rotation of a probe wave and plasma electron density. In classical polaro-interferometry, these values are provided independently by polarimetric and interferometric images. Complex interferometry is an innovative approach in SMF measurement, obtaining information on SMF directly from a phase–amplitude analysis of an image called a complex interferogram. Although the theoretical basis of complex interferometry has been well known for many years, this approach has not been effectively employed in laser plasma research until recently; this approach has been successfully implemented in SMF measurement at the Prague Asterix Laser System (PALS). In this paper, proprietary construction solutions of polaro-interferometers are presented; they allow us to register high-quality complex interferograms in practical experiments, which undergo quantitative analysis (with an original software) to obtain information on the electron density and SMFs distributions in an examined plasma. The theoretical foundations of polaro-interferometric measurement, in particular, complex-interferometry, are presented. The main part of the paper details the methodology of the amplitude–phase analysis of complex interferograms. This includes software testing and examples of the electron density and SMF distribution of a laser ablative plasma generated by irradiating Cu thick planar targets with an iodine PALS laser at an intensity above about 1016 W/cm2.
Real-time monitoring of hydrogel rheological property changes and gelation processes using high-order modes of cantilever sensors
Authors: Cesewski Ellen , Singh Manjot , Liu Yang , Zhang Junru , Haring Alexander P. , Johnson Blake N.
Published: November 2020

Here, we report that high-order modes of dynamic-mode piezoelectric cantilever sensors near 1 MHz persist in hydrogels and enable sensitive characterization of hydrogel viscoelastic properties and real-time monitoring of rheological property changes. Continuous tracking of the resonant frequency (fn), phase angle and impedance at resonance, and quality factor (Qn) of low- and high-order modes in piezoelectric-excited milli-cantilever (PEMC) sensors enabled the characterization of hydrogel viscoelastic properties and real-time monitoring of gelation processes (fair, low = 38.1 kHz and fair, high = 836.9 kHz). Various spectral features of the sensor's impedance response, including changes in fn, phase angle, Qn, and impedance, enabled sensing of changes in alginate and polyethylene glycol dimethacrylate (PEGDMA) hydrogel composition and low-frequency viscoelastic properties characterized by DMA across the 0.5–4 wt. % and 8–18 wt. % concentration ranges, respectively. The phase angle and impedance responses exhibited the highest sensitivities to changes in alginate and PEGDMA hydrogel storage modulus (E′) and loss factor [tan(δ)]. High-order modes exhibited an increased dynamic range upper limit (33.2 kPa) and reduced limit of detection (90 Pa) for the detection of changes in E′ relative to low-order modes (23.4 kPa and 230 Pa, respectively). This work suggests that high-order modes of PEMC sensors near 1 MHz compliment low-order modes in the 1–100 kHz frequency range for sensitive characterization and real-time monitoring of hydrogel rheological properties across a wide frequency range. Millimeter-scale piezoelectric cantilever sensors appear to be a promising characterization and processing tool for hydrogel materials research.
Numerical analysis of Richtmyer–Meshkov instability of circular density interface in presence of transverse magnetic field
Authors: Zhang Huan-Hao , Zheng Chun , Aubry Nadine , Wu Wei-Tao , Chen Zhi-Hua
Published: November 2020

Richtmyer–Meshkov instability (RMI) caused by the interaction of a shock wave and a density interface in the presence of a transverse magnetic field is investigated numerically using the ideal compressible magneto-hydro-dynamic (MHD) equations. The MHD equations are solved with the corner transport upwind + constrained transport algorithm that guarantees the divergence-free constraint on the magnetic field. The numerical results clearly capture the evolution of the density interface induced by the RMI for both HD and MHD situations, which are in good agreement with the previous experimental and numerical results. Moreover, current numerical results reveal a potential stabilizing mechanism of the flow instability by the transverse magnetic field: it is found that the magnetic tension produces a torque on the interface fluid, which is opposite to the torque driven by the velocity shear; therefore, the Kelvin–Helmholtz instability on the density interface caused by the velocity shear is effectively suppressed. In addition, detailed information about the magnetic strength, magnetic energy, magnetic tension, and vorticity on the density interface is also quantitatively analyzed, and the results suggest that the RMI is quite an efficient mechanism for the amplification of the magnetic field, which, in turn, enhances the suppression of the flow instability.
Numerical investigation of two hollow cylindrical droplets vertically impacting on dry flat surface simultaneously
Authors: Liu Xiaogang , Wang Yanhua , Wang Zhongyi , Sun Haiou , Luan Yigang
Published: November 2020

In this paper, the effect of two hollow droplets’ impact on a solid substrate is numerically studied. A coupled level set and volume of fraction method is used to investigate the fluid dynamics and heat transfer characteristics of two hollow cylindrical droplets vertically impacting on a dry flat surface simultaneously. Numerical results show that, different from two continuous dense droplets, counter-jet at impact point (CJIP) is observed as a distinguished feature during the two hollow droplets’ impact process. However, counter-jet at symmetric point (CJSP) is formed in the vicinity of the symmetric point for both two hollow and dense cylindrical droplets. The analysis of pressure and velocity distribution is performed. It is shown that the formation of CJSP and CJIP is mainly caused by the pressure gradient. Upon further analysis of average heat flux, the formation of CJIP and the liquid shell rupture are the two main factors determining that the hollow droplet has a lower heat transfer capacity with the flat solid wall than that of the dense droplet. Through the investigation about the effect of impact velocity on fluid flow and heat transfer characteristics, the spread factor, the height of CJSP and CJIP, and the average heat flux will all increase with higher impact velocity. These results will provide a better understanding of hollow droplet impingement and heat transfer on flat surfaces.
Surface hopping with cumulative probabilities: Even sampling and improved reproducibility
Authors: Parker Shane M. , Schiltz Colin J.
Published: November 2020

Trajectory surface hopping simulations of photochemical reactions are a powerful and increasingly important tool to unravel complex photochemical reactivity. Within surface hopping, electronic transitions are mimicked by stochastic hops between electronic potential surfaces. Thus, statistical sampling is an inescapable component of trajectory-surface-hopping-based nonadiabatic molecular dynamics methods. However, the standard sampling strategy inhibits computational reproducibility, limits predictability, and results in trajectories that are overly sensitive to numerical parameters like the time step. We describe an equivalent approach to sampling electronic transitions within fewest switches surface hopping (FSSH) in which hops are decided in terms of the cumulative probability (FSSH-c) as opposed to the usual prescription, which is in terms of the instantaneous conditional probability (FSSH-i). FSSH-c is statistically equivalent to FSSH-i and can be implemented from trivial modifications to an existing surface hopping algorithm but has several key advantages: (i) a single trajectory is fully specified by just a handful of random numbers, (ii) all hopping decisions are independent of the time step such that the convergence behavior of individual trajectories can be explored, and (iii) alternative integral-based sampling schemes are enabled. In addition, we show that the conventional hopping probability overestimates the hopping rate and propose a simple scaling correction as a fix. Finally, we demonstrate these advantages numerically on model scattering problems.
Theoretical study of SPP properties based on black phosphorus–graphene van der Waals heterostructure
Authors: Zhou Feng , Liang Chen
Published: November 2020

We theoretically investigate the surface plasmon polariton (SPP) properties based on black phosphorus–graphene van der Waals heterostructures that can be tuned by both the incident light angle of black phosphorus and Fermi level of graphene. We elucidate the angle-dependent SPP properties for the hybrid structure from the visible regime to mid-infrared regime. The results show that the largest SPP propagation distance is obtained in the zigzag direction of black phosphorus except when the wavelength is tuned from 380 nm to 480 nm in the visible regime and 1 µm–1.2 µm in the near infrared regime. We also reveal the quasi-linear and quasi-square linear relationship between the SPP propagation distance and Fermi level of graphene for different regimes. Our work would be of great value to construct and optimize the angle-dependent and tunable SPP devices based on the hybridization of different 2D materials.
Applied research on the numerical simulation of Cu and Cd transport laws in a metal mining area
Authors: Xie Chengyu , Qin Yaguang , Chao Lei , Shi Dongping
Published: November 2020

China is paying increasing attention to the ecological environment, and heavy metal pollutants produced during mining and smelting in metal mines have caused serious environmental problems to the soil in mining areas. Heavy metal pollution by Cd and Cu in the soil of a metal mining area in Leiyang City, Hunan Province, China, is used here as an example. The total content of heavy metals and the contents of various forms were determined. High Cd and Cu contents were found, and the main forms of the two heavy metals were in the residual state. Then, using the COMSOL software, the migration and evolution of Cu and Cd in the soil were predicted by real simulations. On this basis, a soil management plan was explored. The migration model shows that within 30 days, the pollutant concentration gradually decreases with increasing depth, and most of the heavy metals are concentrated in the surface layer of the soil; after migration, Cd and Cu have different concentrations at various depth levels in the soil. Among them, the soil concentration is the highest in the range of 0 cm–10 cm depth. As the depth reaches 30 cm, the concentration gradually stabilizes. The conclusions of the study provide a scientific basis for the rational use and ecological restoration of mining areas and the prevention and control of soil pollution in mining areas.
Development of quadrupole susceptibility automatic calculator in sum frequency generation spectroscopy and application to methyl C—H vibrations
Authors: Mori Wataru , Wang Lin , Sato Yamato , Morita Akihiro
Published: November 2020

Sum frequency generation (SFG) spectroscopy has been established as a powerful interface probe technique based on the electric dipole approximation, while possible signals of quadrupole and bulk origin have also been known for a long time. In this work, we developed a computational tool, namely, Qsac (quadrupole susceptibility automatic calculator), to evaluate the comprehensive contributions of the dipole/quadrupole and interface/bulk in the arbitrary vibrational bands of SFG spectra. The calculations of relevant susceptibility terms are performed on the basis of the theory of energy representation using quantum chemical calculation and molecular dynamics simulation, which allows for semi-quantitative comparison among these terms on the same footing. We applied the Qsac to the methyl C—H stretching bands of organic molecules and found a general trend that the weak asymmetric bands are more sensitive to the bulk contribution than the symmetric ones. The phases of interface and bulk terms tend to cancel in the asymmetric band, which results in the reduced band intensity in the SFG spectra.
A semiclassical Thomas–Fermi model to tune the metallicity of electrodes in molecular simulations
Authors: Scalfi Laura , Dufils Thomas , Reeves Kyle G. , Rotenberg Benjamin , Salanne Mathieu
Published: November 2020

Spurred by the increasing needs in electrochemical energy storage devices, the electrode/electrolyte interface has received a lot of interest in recent years. Molecular dynamics simulations play a prominent role in this field since they provide a microscopic picture of the mechanisms involved. The current state-of-the-art consists of treating the electrode as a perfect conductor, precluding the possibility to analyze the effect of its metallicity on the interfacial properties. Here, we show that the Thomas–Fermi model provides a very convenient framework to account for the screening of the electric field at the interface and differentiating good metals such as gold from imperfect conductors such as graphite. All the interfacial properties are modified by screening within the metal: the capacitance decreases significantly and both the structure and dynamics of the adsorbed electrolyte are affected. The proposed model opens the door for quantitative predictions of the capacitive properties of materials for energy storage.
Instability of the realizable k–

ε

turbulence model beneath surface waves
Authors: Fuhrman David R. , Li Yuzhu
Published: November 2020

Recent research has proved that most widely used two-equation turbulence closure models are unconditionally unstable in regions of nearly potential flow having finite strain, as commonly found beneath non-breaking surface waves. In this work, we extend such analysis to consider the popular realizable k–ε turbulence model. It is proved that this model, unlike all others thus far analyzed, is only conditionally unstable in such regions due to the addition of viscosity in the ε dissipation term. A method for formally stabilizing the model in the problematic regions is likewise developed. The results of the analysis, using both standard and stabilized turbulence closures, are confirmed via numerical simulations of progressive surface wave trains using a computational fluid dynamics model. Important qualitative differences are likewise demonstrated in simulations involving spilling breaking waves. (In the above, k is the turbulent kinetic energy density, and ε is the turbulence dissipation rate.)
Collagen, intramuscular fat and proteolysis affect Warner-Bratzler shear-force of muscles from Bos taurus breed types differently at weaning, after backgrounding on pasture, and after feedlotting
Authors: Therkildsen Margrethe , Greenwood Paul L. , Starkey Colin P. , McPhee Malcolm , Walmsley Brad , Siddell Jason , Geesink Geert
Published: November 2020

Context
The texture of beef is highly important for the eating experience, and there is a continued interest in understanding the biochemical basis for the variation in texture between cattle and their meat cuts in order to improve and minimise variation in tenderness due to production and processing factors.

Aims
The present study aimed to investigate the impact of characteristics of meat on Warner-Bratzler shear-force (WBSF) as an indicator of texture of beef as affected by breed type, age/feeding phase, and muscle.

Methods
Seventy-five steers of three breed types (Angus, Hereford and Wagyu × Angus) were slaughtered after weaning 6 months old (n = 15), after backgrounding 17 months old (n = 30) and after feedlotting 25 months old (n = 30). At slaughter three muscles (M. supraspinatus, M. semitendinosus and M. longissimus lumborum) were sampled from each steer, and pH, intramuscular fat and collagen content, sarcomere length, and proteolysis (desmin degradation) were measured and used to explain the variation in WBSF after 7 and 14 days of aging.

Key results
Meat from Hereford and Angus steers had higher WBSF after 7 days of aging compared with Wagyu × Angus steers, but after 14 days of aging there was only a difference between Hereford and Wagyu × Angus in the M. supraspinatus and M. semitendinosus. The WBSF of the young weaned steers and steers slaughtered after backgrounding were dependent on the degree of proteolysis in the muscles, whereas for steers slaughtered after feedlotting the content of collagen was more important for the WBSF. The amount of intramuscular fat had a significant impact on the differences in WBSF within the specific muscle studied. In contrast to the general dogma that WBSF increase with age, WBSF decreased in M. semitendinosus and M. longissimus lumborum from the weaned 6-month-old steers to the 25-month-old steers finished in feed-lot, whereas in M. supraspinatus the older feed-lot finished steers had a higher WBSF.

Conclusion
The factors contributing to the Warner-Bratzler shear force of beef depends on the age/feeding phase of the animal and the muscle and less on the breed type.

Implications
Optimisation of texture in beef through breeding and production should address different traits dependent on the age/feeding phase of the slaughter animal.
Monitoring and analysing grassland ecosystem service values in response to grassland area changes – an example from northwest China
Authors: Manlike Asiya , Sawut Rukeya , Zheng Fengling , Li Xuesen , Abudukelimu Rena
Published: November 2020

Using remote sensing technology, this study evaluates changes in mountain grassland ecosystem service values (ESVs) and the factors driving them. Degraded grasslands in Urumqi city, northwest China, reached 1.22×105 ha in 2000. However, the grassland degradation rate decreased by 387ha annually from 2000 to 2015. Total grassland ESVs decreased unpredictably with an annual reduction of USD$1.64×107. Ecological losses were mainly caused by degradation of mountain desert grassland, mountain desert steppe-type rangeland, and mountain meadow and mountain steppe-type rangeland. Among individual ESVs, grasslands contributed more to regulating and supporting services, while grassland provisioning and cultural services were relatively low, comprising 0. 7 and 0.5% of the total ESV respectively. The mean Moran’s I value was 0.869 for grassland ESVs (from 1994 to 2015), and exhibited high spatial autocorrelation. A driving factor analysis indicated that grassland degradation is continuing as a consequence of meteorological factors and overgrazing. Controlling grazing intensity has a positive impact on growth of grassland ESVs.
Toward non-hagiographical reflections on Zimbabwe’s ‘heroes’: Dumiso Dabengwa’s history
Authors: Moore David
Published: November 2020

Dumiso Dabengwa’s death in May 2019 offers the opportunity to reflect on Zimbabwe’s fraught liberation struggle and its consequences today.
1
That Robert Mugabe’s passing was a few months later makes such considerations more pertinent. This article thus revisits some of the liberation war’s moments of evident tension between its two main nationalist movements, as well as those in the post-1980 era. It also considers some of Dabengwa’s last, most historically important and philosophically interesting reflections.
Creation and propagation of a single magnetic domain wall in 2D nanotraps with a square injection pad
Authors: Hoang Duc-Quang , Cao Xuan-Huu , Nguyen Hoai-Thuong , Dao Vinh-Ai
Published: November 2020

Polycrystalline permalloy 2D nanotraps with a thickness of 20 nm were studied using a Lorentz microscope associated with micro-magnetic simulations. Each trap was designed to create a single head-to-head domain wall. The traps consist of a few nanowires with an in-plane dimension of w nm × 1000 nm (w = 150, 200 and 250 nm). Some structures with an injection pad were also designed to create a single domain wall and propagate it through the structure with the said injection pad. A few of them were patterned to study the nucleation and propagation behavior of such nucleated domain walls using both horizontal magnetic field and injection pad approaches. The case of a domain wall created at the first corner of the trap with a wire width of 200 nm was systematically studied, while single and multiple domain walls can also be created and propagated with or without an injection structure. The characteristics of such movements were exploited with an emphasis on a single head-to-head domain wall.
Neuronal growth from a volume perspective
Authors: Braïni Céline , Bugnicourt Ghislain , Villard Catherine
Published: November 2020

Microfluidic-based fluorescent exclusion method allows to tackle the issue of neuronal growth from a volume perspective. Based on this technology, we studied the two main actin-rich structures accompanying the early stages of neuron development, i.e. growth cones, located at the tip of growing neuronal processes, and propagative actin waves. Our work reveals that growth cones tend to loose volume during their forward motion, as do actin waves during their journey from the cell body to the tip of neuronal processes, before the total transfer of their remaining volume to the growth cone. Actin waves seem thus to supply material to increasingly distant growth cones as neurons develop. In addition, our work may suggest the existence of a membrane recycling phenomena associated to actin waves as a pulsatile anterograde source of material and by a continuous retrograde transport.
A SOP planning method for distribution network based on improved genetic algorithm considering EV integration
Authors: Li Ziang , Zhang Lu
Published: November 2020

With the progress of electric vehicles, there comes a huge number of problems about cost inflation and workload increases in power distribution systems, which caused by the growing number of electric vehicles plugging. Hence, an optimal planning scheme of soft open point (SOP) considering the connection of electric vehicle to power distribution system is proposed. First of all, a SOP two-layer planning model for site selection and capacity determination was established to seek for site selection and capacity determination, so as to minimize the cost. The hybrid optimization algorithm composed of improved genetic algorithm and power flow algorithm was used to solve the problem. Further, the variation of voltage level, before and after the SOP connected to the distribution network, is also analyzed. Finally, the rationality and feasibility of the two-layer programming model of SOP site selection and constant capacity and the hybrid optimization algorithm composed of improved genetic algorithm and power flow algorithm are analyzed with IEEE 33 node example system, and the planning conclusion of effectively reducing the operating cost of the distribution system is obtained. After plugging in SOP according to the planning results, the node voltage value, the average per unit value and the performance of the distribution system are improved to a certain extent. Meanwhile, the operation efficiency, relative error and the convergence capacity according to the modified algorithm are superior to conventional algorithm.
Tri-level allocation method of distributed energy storage system based on sharing strategy in active distribution networks
Authors: Dai Xianzhong , Zhang Yan , Zhang Chen , Cao Zijian , Shen Ruibao , Tong Bo
Published: November 2020

More and more distributed energy storage (DES) are integrating into active distribution networks (ADNs), which has a positive effect on both distribution companies (DISCOs) and consumers. In order to achieve peak-load shifting and reduce the electricity purchasing costs, from the perspective of an independent energy storage operator, a tri-level allocation model of DES in an ADN is built based on a sharing strategy. The tri-level model is a multi-objective optimization problem: the upper-stage model optimizes the siting and sizing of DES with the objective of minimizing the annual costs of investment; the middle-stage model realizes an optimal distribution of energy storage capacity to the DISCO and consumers with the objective including the operating costs of the DISCO and consumers, and peak-valley differences; in the lower-stage model, the optimal operation scheme of DES can be acquired with the objective of minimizing the operating costs of the DISCO and consumers. A method combining adaptive genetic algorithm (GA) and second-order cone programming (SOCP) is adopted to solve the model. Simulation results on the IEEE 33 bus system show that the tri-level allocation method can effectively reduce the RES investment costs, reduce the peak-valley differences, and improve the revenues of both the DISCO and consumers.
Research on Three-phase Unbalance Control of Distribution Area Based on Intelligent Fusion Terminal
Authors: Dongdong Lv , Tao Yang , Siyang Deng , Zhu Liu , Wenjing Li
Published: November 2020

As the three-phase four-wire system is used in power transmission and distribution in our country, the single-phase load is the most part of power consumption. The three-phase imbalance of voltage and current on the outlet side of transformers may occur due to the unexpectedly increase or decrease of the load in a certain phase of the low-voltage distribution network. This phenomenon will reduce the service time of the equipment and the power quality of the power supply. A multiple population genetic algorithm (MPGA) is proposed in this paper to treat this problem. Intelligent fusion terminal (IFT) is used as the hardware application platform to communicate with phase-change switch in order to execute the optimal strategy, the three-phase current of the load side would be balanced after the strategy is executed. An example is simulated with MATLAB to show the effectiveness of MPGA.
Discussion on Urban Distribution Network Planning Based on Key Tech-nologies of Smart Distribution Network
Authors: Wang Shuchun , Sun Xiaoguang , Geng Jianyu , Han Yuan , Zhang Chunyong , Zhang Weihua
Published: November 2020

Urban distribution network planning is the key technology of smart distribution network. The survey method is used to summarize the economic evaluation, load forecasting, and power grid planning of urban power grids. On this basis, the corresponding methods and solutions to the problem are proposed, including: improving the professional literacy of relevant technical practitioners, establishing and improving a smart distribution network supervision mechanism, and strengthening relevant maintenance of smart distribution network equipment. Optimize planning quality. Enable power companies to fully meet the development needs of modern society, better ensure the safety of power grid projects, and effectively plan urban power grids.
Study on the Design of Comprehensive Test Environment for the Performance of Cable Tunnel Patrol Robot
Authors: Li Chong , Li Yong , Li Sun , Wang Kenan , Li Tao , Guo Rui
Published: November 2020

The cable tunnel patrol robot has gradually attracted the attention of cable operation and maintenance units due to its high inspection efficiency and strong work safety[1]. In order to test the functions of cable tunnel patrol robot such as autonomous inspection, defect identification and fire fighting, a targeted functional test environment for cable tunnel patrol robot was designed, including autonomous inspection environment and defect detection environment. The test environment can not only be used to test the performance of cable tunnel patrol robot, but also provide an important reference for the construction of autonomous inspection environment for cable tunnel robot.
Characteristics of Reactive Power Compensation for Islanded Microgrids Based on Synchronized Current Phasor Control
Authors: Jin Jiaxin , Shi Qianhong , Wang Zhijun , Ding Lei
Published: November 2020

Synchronized Current Phasor Control (SCPC) is a new control method proposed recently for islanded microgrids. This paper firstly investigates the reactive power compensation characteristics of the SCPC islanded microgrid with I-V droop control, then analyzes the influence of the droop coefficient on it. Through this study, we find that the traditional reactive power compensation strategies are no longer adapted to SCPC islanded microgrids, since their characteristics of reactive power compensation are different from the traditional grid or other islanded microgrids controlled by the typical methods.
Trade-off of Tactical Technical Indicators Based on Improved Branch and Bound Method
Authors: Gao Sisi , Yang Xinhe , Jin Jie , Wang Jiasheng
Published: November 2020

In view of the relative lack of research on the method of determining the Tactical Technical Indicators requirements through the typical indexes trade-off model in the domestic combat technology index demonstration, based on the non-convex quadratic programming problem widely used in engineering design and economies of scale, a new linear relaxation is proposed with the help of the characteristics of the quadratic function The method uses the new ultra-rectangular reduction and pruning techniques according to the differential median theorem, and uses the branch and bound method to solve, which provides a quantified and efficient method for determining the technical parameters of the weapon equipment design.
Experimental Study on Integration Bamboo Elastic Modulus with Wave Velocity Nondestructive Testing Method
Authors: Wei Liuchuang , Wei Ping , Yang Yong
Published: November 2020

Integrated bamboo is widely used in daily life and industrial production. This paper explores and studies the determination method of its elastic modulus. In this paper, based on the wave propagation principle, the wave velocity method is proposed. This was used to carry out experimental design and experiment, and the results were compared, analyzed and discussed.
Research on Rural Electronic Commerce Logistics in Henan Province
Authors: Meng Fanyue
Published: November 2020

The aims are that improve the living standard of rural areas in Henan Province, and contribute to the building of a well-off society in an all-round way. According to the present situation of rural e-commerce logistics in Henan Province and the national support policy, the paper puts forward some suggestions. The paper mainly through the questionnaire survey method. It analyzes the present situation and the problems, and puts forward feasible suggestions. For rural development, it improves rural living standards. It can contribute to narrowing the gap between urban and rural areas.