bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Reliability of Straight Thread Connection of Reinforcement Cage of Bridge Foundation
Authors: Li Jinhui , Shang Xiaodong , Yuan Minmin
Published: April 2021

With the continuous improvement of bridge construction technology in our country, although the service life of the bridge has been greatly extended, the mechanical connection technology of steel bar in the technology is still in the stage of steel bar straight thread connection, which is nearly 30 years behind that of foreign countries. According to the development status and application requirements of bridge construction in China, it is of great practical significance to explore new technologies and methods to solve the problem of insufficient strength of straight thread connection of reinforcement. In this paper, the reliability of the straight thread reinforcement connection in the bridge foundation reinforcement cage connection technology is studied as the main breakthrough point, and the main problems encountered in the application of the straight thread reinforcement connection technology in the bridge reinforcement cage connection are analyzed.
Research on Settlement Prediction of Small Water Conservancy Project based on ELM Model Optimized by Genetic Algorithm
Authors: Yang Ruizi
Published: April 2021

To find suitable for small water conservancy engineering standard method for prediction of subsidence. This paper based on the genetic algorithm GA optimization extreme learning machine, three different ELM model activation function. From this, six computational models are obtained. According to the input of groundwater dynamic changes, precipitation, temperature and soil four indicators of the two kinds of input combinations, a total of 12 kinds of model input. It’s concluded that the optimal settlement prediction model, the results showed that: Ga-ELMsin model shows high accuracy, and genetic algorithm can improve the calculation accuracy of ELM model. Groundwater dynamics is the main factor affecting settlement.
Research on Design and Operation Method of Dewater and Filled System for Cushion Pool of High Dams ——Taking the project of BHT hydropower plant in China as an example
Authors: Jie Fang , Chunjian Cao , Shengbing Li
Published: April 2021

Dam is set in large hydropower station. Cushion pool is built behind the dam for the flood discharge and energy dissipation of the reservoir. Operation of flood discharge and energy dissipation for some time, Cushion pool is dewatering and structure safety of which is study, then cushion pool is filled. Temporary dewater and filled system is used by previous engineer, but is arranged and controlled hard. Based on need of the cushion pool dewatering and filling, for an example of Baihetan hydropower station, necessity and feasibility are study. Then a permanent dewatering and filling system is designed for cushion pool. Design principle and arrange method are described. Many technical difficulties are study and resolved such as effect of valley deformation on the control system of dewatering and filling, demand of dewatering and filling device parameter, performance quota formulate based on large water level amplitude, protective measures in the working condition of much silt on the downstream and humidity in the equipment room of the second-dam and project of dewater drainage outlet under the water. By gravity drainage and filling based on water level difference and pump drainage, much electric energy is saved and personnel operating environment and working conditions are improved.
Take Shuibu Town of Taishan city as an example to study the application of GIS in small towns under the background of “Muti-planning integration”
Authors: Liao Yulu
Published: April 2021

With the proposal of land planning strategy and the development of GIS information technology and big data, geographic information technology and big data are widely used in the field of urban and rural planning, providing new technical support for the implementation of “muti-planning integration”. As the reserve force for development, small towns have great research value. This study selects Shuibu Town of Taishan city to study the construction and management of Urban Land GIS database in order to provide working ideas for the construction of GIS data platform in small towns.
Considerations on the Protection of Historic Buildings in Wuhan：Starting from Tanhualin Protection
Authors: Zhuang Yulu
Published: April 2021

This paper takes the historical and cultural area of Tanhualin in Wuchang District as an example, from the historical construction present situation, the value of historical architecture, discusses three aspects of the historical building protection measures, and finally draws the conclusion: historical building protection needs to emphasize on protection, do repair old as before, to protect the culture at the same time also should pay attention to regain its vitality, achieve sustainable development, and carefully reconsider historical buildings in the present age, the function of space positioning.
Discontinuous mechanical analysis of manifold element strain of rock slope based on open source Gempy
Authors: Wu Jie , Sun Bingyang
Published: April 2021

Three-dimensional geological modeling is an important means to transparently study the three-dimensional geological spatial structure and change trend of major complex rock mass projects, and plays a very important role in the decision-making and mining of major projects. Today’s modeling methods rely too much on the required data, the process is cumbersome and the time is relatively long. Therefore, based on the above discussion, this article uses a complete open source code geological modeling method here, based on the implicit potential field interpolation method of the open source GemPy package, using this interpolation algorithm can be relatively simple to build a complex full three-dimensional geological model, Including fault network, fault surface interaction, unconformity and dome structure. The article describes in detail how to construct the faults and strata of the 3D geological model, and how to add topographic maps, and use the generated model as input data, use MOOSE to voxelize it, and export the required data, use NMM Perform stability analysis. This method has the advantages of simple operation, fast modeling speed, and visual interactive operation. The establishment of a three-dimensional geological model of the fractured rock mass was very effective, laying a solid foundation for the subsequent stability analysis.
Research on the Construction of Dongying Wetland City during the “14th Five-Year Plan”
Authors: Wang Jiaming , Zhang Yunfei , Du Xueyi
Published: April 2021

The 18th National Congress of the Communist Party of China proposed to place ecological civilization construction in the important position of “five in one”, and with the transformation of economic development mode, focusing on high-quality, scientific, and reasonable urban development model has become the research focus of experts and scholars, with certain theories And practical significance. Taking the opportunity of Dongying being rated as an “International Wetland City”, this article studies the construction of Dongying Wetland City during the “14th Five-Year Plan” period. Starting from the investigation of the current situation, it analyzes the current situation of Dongying City’s wetland and puts forward the problems in the construction of Dongying City’s wetland city. Combing the experience of Haikou, Berlin, Freiburg, and Vienna experience in wetland city construction at home and abroad, and analyzed the wetland foundation from the four perspectives of wetland protection, wetland restoration, wetland utilization, and wetland management, and proposed Dongying The city’s policy recommendations for wetland construction are designed to provide suggestions for the construction of Dongying wetland city during the “14th Five-Year Plan” period, to provide a reference for the same type of regions, and to provide a reference for the research of experts and scholars in the same field.
Impact study of NOOR 1 project on the Moroccan territorial economic development
Authors: Laaroussi Amale , Bouayad Abdelrhani , Lissaneddine Zakaria , Alaoui Lalla Amina
Published: April 2021

Morocco is one of the countries investing more and more in Renewable Energy (RE) technologies to meet the growing demand for energy and ensure the security of supply in this sector. The number of solar projects planned and implemented, as well as solar thermal projects in the form of Concentrating Solar Power (CSP) installations is steadily increasing. Many of these installations are designed as large utility systems. In order to provide strong evidence on local, regional and even national impacts, this article examines the impacts of large-scale renewable energy projects on territorial development, based on a case study of the NOOR 1 (Concentrated Solar Power (CSP)) project in Ouarzazate, Morocco. The data collected during this study, conducted through semi-structured interviews with experts, stakeholders, local community representatives and combined with an analysis of documents provided by the NOOR 1 project managers, investors and consulting firms specialized in the field of Renewable Energy, provide detailed evidence on the type and magnitude of impacts on the economic development of the Moroccan southern region where the NOOR 1 plant is located. The data collected is analyzed using NVIVO software. The study results in a consolidated list of many impacts with varying levels of significance for different stakeholder groups, including farmers, youth, women, community representatives and small and medium firms owners. It should be noted that the importance of analyzing the economic impact of large infrastructure projects is widely recognized, but so far, there is little published in the academic and professional literature on the potential impacts of these projects at the local level. Even less information is available on the local impacts of large-scale project implementation in Morocco. While many macroeconomic studies have fed the recent surge in investment in RE projects with the promise of multiple social, economic, environmental, and even geopolitical benefits at the macro level, public debates and discussions have raised considerable doubts. The question of whether these promises would also leave their marks at the local level has also arisen. Despite these uncertainties, very few academics and practitioners have conducted research to empirically develop a good understanding of the impact of RE projects at the local level. To fill this research gap, the economic impact analysis of NOOR 1 provides a detailed empirical overview, which allows a better understanding of the effects that the infrastructure developments of Concentrated Solar Power (CSP) plants can have on the economic environment in which they are located.
Radial incision and cutting combined with balloon dilation for refractory pancreaticojejunostomy anastomotic strictures
Authors: Inoue Tadahisa , Ibusuki Mayu , Kitano Rena , Kobayashi Yuji , Ohashi Tomohiko , Sumida Yoshio , Nakade Yukiomi , Ito Kiyoaki , Yoneda Masashi
Published: April 2021

Background and study aims Endoscopic balloon dilation (BD) and temporary stent placement for pancreaticojejunostomy anastomotic stricture (PJAS) achieves good short-term outcomes; however, stricture recurrences remain frequent. We examined the feasibility of performing radial incision and cutting (RIC) combined with BD for refractory PJAS.

Patients and methods Five consecutive patients with refractory PJAS who underwent RIC with BD between 2015 and 2018 were retrospectively investigated. We evaluated the technical and clinical success, adverse event (AE), and recurrence rates associated with RIC with BD.

Results In all five patients, technical and clinical success were achieved. Pancreatic stone removal was simultaneously performed in one patient. The mean procedure time was 18 minutes (range 12–23 minutes). There were no procedure-related AEs. All patients were followed for over 2 years, with a mean follow-up period of 33 months (range 24–40 months). During the follow-up period, none of the patients developed stricture recurrence and all anastomoses remained patent.

Conclusions This is the first report of RIC with BD for the treatment of refractory PJAS, showing favorable results. This combined procedure might be a useful option for treating refractory PJAS.
The 2016 Edition of the WHO Classification of Primary Brain Tumors: Applicable to Assess Individual Risk of Recurrence in Atypical Meningioma? A Single-Center Experience
Authors: Unteroberdörster Meike , Michel Anna , Darkwah Oppong Marvin , Jabbarli Ramazan , Hindy Nicolai El , Wrede Karsten H. , Sure Ulrich , Pierscianek Daniela
Published: April 2021

Background and Study Aims/Object Despite the relevance of molecular criteria for brain tumor diagnosis and prognosis, meningioma grading is still solely based on histologic features. Atypical meningiomas (AMs; WHO grade II) display a great histologic heterogeneity and individual courses of disease can differ significantly. This study aimed to identify clinically aggressive AMs that are prone to early recurrence after gross total resection (GTR) by assessing a specific histologic score.

Patients and Methods A retrospective analysis of 28 consecutive patients (17 females and 11 males; mean age of 62 years [range: 35–88 years]) treated in our institution between January 2006 and December 2015 was performed. Basic demographic and clinical characteristics were assessed. A scoring scale was designed to address the histologic diversity by summing up the individual histologic features in every tumor sample. According to that, points were awarded as follows: major AM defining criterion (3 points) and minor criterion (1 point).

Results The subclassification based on our specific histologic score revealed no significant difference in frequency of one (46.4%) or two (42.9%) AM defining features; three criteria were less frequently seen (10.7%). Mean follow-up was 61.89 ± 9.03 months. Local recurrence occurred in 35.7% after a mean time of 37.4 ± 22.6 months after primary surgery. Age > 60 years was significantly associated with a shorter progression-free survival (PFS). There was a trend toward shorter PFS with increasing scores, tantamount with the presence of several AM defining histologic criteria in one sample. No tumor relapse was seen when diagnosis was based only on minor criteria.

Conclusion AMs display a histologic diversity. There is a trend toward shorter PFS with increasing numbers of AM defining histologic features. The inclusion of this score in the decision algorithm regarding further treatment for patients >60 years after GTR might be helpful and should be evaluated in further studies.
Laminectomy versus Unilateral Hemilaminectomy for the Removal of Intraspinal Schwannoma: Experience of a Single Institution and Review of Literature
Authors: Dobran Mauro , Paracino Riccardo , Nasi Davide , Aiudi Denis , Capece Mara , Carrassi Erika , Lattanzi Simona , Rienzo Alessandro DI , Iacoangeli Maurizio
Published: April 2021

Background and Study Aims Spinal schwannomas are benign slow-growing tumors, and gross total resection is the gold standard of treatment. The conventional surgical approach is laminectomy, which provides a wide working area. Today minimally invasive surgery (MIS) is popular because it is associated with shorter hospital stay, less operative blood loss, minimized tissue traumas and relative postoperative pain, and, and spine surgery, avoidance of spinal instability.

Material and Methods From January 2016 to December 2019, we operated on 40 patients with spinal intradural extramedullary tumor (schwannoma) with laminectomy or hemilaminectomy. Baseline medical data, including patients' sex and age, tumor location, days of postoperative bed rest, operative time, length of hospitalization, and 1-month visual analog scale (VAS) value were collected and analyzed. Data analysis was performed using STATA/IC 13.1 statistical package (StataCorp LP, College Station, Texas, United States).

Results Hemilaminectomy was associated with faster operative time (p < 0.001), shorter postoperative time spent in bed (p < 0.001), and shorter hospitalization (p < 0.001). At 1-month follow-up, the mean VAS score was 4.6 (1.7) among the laminectomy patients and 2.5 (1.3) among the hemilaminectomy patients (p < 0.001). Postoperative complications occurred in 1 (7.7%) and 7 (25.9%) patients in the hemilaminectomy and laminectomy groups, respectively (p = 0.177).

Conclusions Unilateral hemilaminectomy has significant advantages compared with laminectomy in spinal schwannoma surgery including shorter operative time, less time spent in bed, shorter hospitalization, and less postoperative pain.
Epithelioid Hemangioendothelioma in the Area of the Neurovascular Bundle of the Upper Arm Mimicking a Schwannoma of the Ulnar Nerve
Authors: Scheller Christian , Rampp Stefan , Prell Julian , Strauss Christian , John Endres , Jörg Ukkat , Diessel Linda , Brandt Silvio , Müller Tobias
Published: April 2021

Epithelioid hemangioendothelioma (EH) is a rare vascular malignant sarcoma. To date, there are only two published case reports of EH mimicking nerve sheath tumors of a peripheral nerve. A 41-year-old woman presented with a painful node on the inside of the upper arm and motor deficits of the ulnar nerve. Magnetic resonance imaging (MRI) follow-up and neurosonography revealed a slowly progressive, contrast-enhancing tumor in the area of the neurovascular bundle. A schwannoma of the ulnar nerve was suspected. At surgery, the tumor was adherent to the brachial artery, but not to nerves. Pathology revealed an EH. EH may mimic a nerve sheath tumor and should be taken into consideration, especially because of its potential for metastasis and fatal progression.
Status of Catalase, Glutathione Peroxidase, Glutathione S-Transferase, and Myeloperoxidase Gene Polymorphisms in Beta-Thalassemia Major Patients to Assess Oxidative Injury and Its Association with Enzyme Activities
Authors: Tripathi Poonam , Agarwal Sarita , Tewari Satyendra , Mandal Kausik
Published: April 2021

Beta-thalassemic patients require regular blood transfusion to sustain their life which leads to iron overload and causes oxidative stress. The aim of this study was to investigate the status of variants in genes including GSTM1, GSTT1 (null/present), CT-262 (C > T) and CT-89 (A > T), glutathione peroxidase (GPx), and myeloperoxidase (MPO). The genotype studies were conducted with 200 thalassemia major (TM) patients and 200 healthy controls. Genotyping of GST gene was performed by multiplex polymerase chain reaction (PCR), whereas for CT, GPx and MPO genesvariants PCR- restriction fragment length polymorphism technique used. However, the enzyme activities were measured only in the patients group to assess the association with the genotypes. All enzyme estimations were performed by ELISA. We observed higher frequency of GSTT1 null, CT-89 (A > T), GPx1 198 (C > T) and MPO-463 (G > A) polymorphisms in TM patient than healthy controls. However, CT-262 (C > T) polymorphism was not found to be statistically significantly different between patients and controls. Our results suggest that frequency of null allele of glutathione-S-transferase is significantly high among TM patients. The other alleles CT-89 (A > T), GPx1 198 (C > T), and MPO-463 (G > A) are linked to decreased CT, GPX, and MPO enzyme activities.
A series of coughs create vortices that can carry droplets further
Authors: Yiu Yuen
Published: April 2021

Multi-pulse events, similar to how we cough, create vortical structures that can carry droplets further than single-pulse events.
Advances of beveled mesas for GaN-based trench Schottky barrier diodes
Authors: Huang Fuping , Jia Xingyu , Liu Yajin , Tian Kangkai , Chu Chunshuang , Zheng Quan , Zhang Yonghui , Xin Zhen , Zhang Zi-Hui , Li Qing
Published: April 2021

In this article, we propose and investigate a GaN-based trench metal–insulator–semiconductor barrier Schottky rectifier with a beveled mesa and field plate (BM-TMBS). According to our study, the beveled mesa and field plate structures help to reduce the density of potential lines at the mesa corner and deplete the drift region in two-dimensional mode, respectively. By doing so, the electric field at the bottom corner of the trenches and Schottky contact/GaN interface can be decreased significantly and the breakdown voltage can also be improved remarkably when compared with the conventional TMBS rectifiers and the planar Schottky barrier diodes. Meanwhile, assisted by the beveled mesa structure, the improved current spreading effect and a better conductivity modulation can be obtained in the forward-conduction state. Our studies also show that the electric field profiles and charge-coupling effect can be influenced by the mesa angle, the insulating layer thickness (Tox), and the trench depth (Dtr). As a result, the optimized BM-TMBS rectifiers can obtain a high BV of ∼2 kV and a current density of ∼3 kA/cm2 at the forward bias of 2 V.
How can we describe density evolution under delayed dynamics?
Authors: Mackey Michael C. , Tyran-Kamińska Marta
Published: April 2021

Although the theory of density evolution in maps and ordinary differential equations is well developed, the situation is far from satisfactory in continuous time systems with delay. This paper reviews some of the work that has been done numerically, the interesting dynamics that have emerged, and the largely unsuccessful attempts that have been made to analytically treat the evolution of densities in differential delay equations. We also present a new approach to the problem and illustrate it with a simple example.
A study of the electrical characteristics of a double plug probe aimed to the measurement of plasma fluctuations in a toroidal magnetized plasma
Authors: Alex P. , Barni R. , Ghorbanpour E. , Riccardi C.
Published: April 2021

We have analyzed the electrical characteristics of a plug probe as a function of the orientation relative to the local magnetic field. Our aim was to demonstrate that the probe characteristic, besides a better evaluation of the plasma potential, retains the capability to reliably estimate the electron temperature and density. This feature could be exploited with a multi-pin probe to measure simultaneously the fluctuations of all plasma parameters.
Discrete unified gas kinetic scheme simulation of microflows with complex geometries in Cartesian grid
Authors: He Qing , Tao Shi , Yang Xiaoping , Lu Weijian , He Zongrun
Published: April 2021

Microscale gas flow attracts significant research interest in recent years since it is concerned with a wide range of engineering applications. It is noted that the Navier–Stokes equations-based scheme and the standard lattice Boltzmann method both encounter a great challenge in the simulation of such flows. The newly developed discrete unified gas kinetic scheme (DUGKS) has been demonstrated to be capable of modeling microflows, but presently it is mainly limited to the problems with straight boundaries. In this study, the ghost-cell (GC) immersed boundary method is introduced to the DUGKS for handling curved boundaries. The most attractive feature of the GC method is to set a ghost point inside the solid domain, at which the information is unknown and will be extrapolated linearly from the corresponding wall and image nodes. As for the two latter points, the distribution functions are first evaluated by the inverse distance weighted (IDW) method and then should be corrected according to the impenetrability condition and Maxwellian diffuse-scattering rule. Three typical test cases, including the plane Poiseuille flow, cylindrical Couette flow and flow through porous media are simulated to validate the present IDW-GC-DUGKS. The results demonstrate the accuracy and feasibility of the method for the gaseous microflows.
Molecular dynamics study of water confined in MIL-101 metal–organic frameworks
Authors: Fei Shubo , Hsu Wei-Lun , Delaunay Jean-Jacques , Daiguji Hirofumi
Published: April 2021

Molecular dynamics simulations of water adsorbed in Material Institute Lavoisier MIL-101(Cr) metal–organic frameworks are performed to analyze the kinetic properties of water molecules confined in the framework at 298.15 K and under different vapor pressures and clarify the water adsorption mechanism in MIL-101(Cr). The terahertz frequency-domain spectra (THz-FDS) of water are calculated by applying fast Fourier transform to the configurational data of water molecules. According to the characteristic frequencies in the THz-FDS, the dominant motions of water molecules in MIL-101(Cr) can be categorized into three types: (1) low-frequency translational motion (0–0.5 THz), (2) medium-frequency vibrational motion (2–2.5 THz), and (3) high-frequency vibrational motion (>6 THz). Each type of water motion is confirmed by visualizing the water configuration in MIL-101(Cr). The ratio of the number of water molecules with low-frequency translational motion to the total number of water molecules increases with the increase in vapor pressure. In contrast, that with medium-frequency vibrational motion is found to decrease with vapor pressure, exhibiting a pronounced decrease after water condensation has started in the cavities. That with the high-frequency vibrational motion is almost independent of the vapor pressure. The interactions between different types of water molecules affect the THz-FDS. Furthermore, the self-diffusion coefficient and the velocity auto-correlation function are calculated to clarify the adsorption state of the water confined in MIL-101(Cr). To confirm that the general trend of the THz-FDS does not depend on the water model, the simulations are performed using three water models, namely, rigid SPC/E, flexible SPC/E, and rigid TIP5PEw.
Qian Jian (1939–2018) and his contribution to small-scale turbulence studies
Authors: Shi John Z.
Published: April 2021

Qian (Tsien) Jian (1939–2018), a Chinese theoretical physicist and fluid dynamicist, devoted the second part of his scientific life to the physical understanding of small-scale turbulence to the exclusion of all else. To place Qian's contribution in an appropriate position in the field of small-scale turbulence, a historical overview and a state-of-the art review are attempted. Qian developed his own statistical theory of small-scale turbulence based on the Liouville [“Sur l'équation aux différences partielles,” J. Math. Pures Appl. 18, 71–72 (1853)] equation and a perturbation variational approach to non-equilibrium statistical mechanics, which is compatible with the Kolmogorov–Oboukhov energy spectrum. Qian's statistical theory of small-scale turbulence, which appears mathematically and physically valid, successfully led to his contributions to (i) the closure problem of turbulence; (ii) one-dimensional turbulence; (iii) two-dimensional turbulence; (iv) the turbulent passive scalar field; (v) the cascade model of turbulence; (vi) the universal equilibrium range of turbulence; (vii) a simple model of the bump phenomenon; (viii) universal constants of turbulence; (ix) the intermittency of turbulence; and perhaps most importantly, and (x) the effect of the Taylor microscale Reynolds number (Rλ) on both the width of the inertial range of finite Rλ turbulence and the scaling exponents of velocity structure functions. In particular, Qian found that the inertial range cannot exist when Rλ≪2000. In contrast to the prevailing intermittency models, he discovered that normal scaling is valid in the real Kolmogorov inertial range when Rλ approaches infinity while the anomalous scaling observed in experiments reflects the finite Rλ effect (Qe). He then made a correction to the famous Kolmogorov [“Dissipation of energy in the locally isotropic turbulence,” Dokl. Akad. Nauk SSSR 32(1), 19–21 (1941c) (in Russian); reprinted in Proc. R. Soc. London A 434, 15–17 (1991)] equation and obtained the finite Rλ effect equation or the Kolmogorov–Novikov–Qian equation. He also independently derived the decay law of the finite Rλ effect. Qian steered all of us along the right path to an improved understanding of small-scale turbulence and solutions to its problems. Qian is credited with his contribution to enhanced knowledge about the finite Rλ effect of turbulence, which has profoundly shaped and stimulated thinking about the K41 turbulence, the K62 turbulence, and the finite Rλ turbulence.
Explosive synchronization in interlayer phase-shifted Kuramoto oscillators on multiplex networks
Authors: Kumar Anil , Jalan Sarika
Published: April 2021

Different methods have been proposed in the past few years to incite explosive synchronization (ES) in Kuramoto phase oscillators. In this work, we show that the introduction of a phase shift α in interlayer coupling terms of a two-layer multiplex network of Kuramoto oscillators can also instigate ES in the layers. As α→π/2, ES emerges along with hysteresis. The width of hysteresis depends on the phase shift α, interlayer coupling strength, and natural frequency mismatch between mirror nodes. A mean-field analysis is performed to justify the numerical results. Similar to earlier works, the suppression of synchronization is accountable for the occurrence of ES. The robustness of ES against changes in network topology and natural frequency distribution is tested. Finally, taking a suggestion from the synchronized state of the multiplex networks, we extend the results to classical single networks where some specific links are assigned phase-shifted interactions.
Influence of cation size on the thermoelectric behavior of salt-doped organic nanocomposite thin films
Authors: Stevens Daniel L. , Ortiz Adrian , Cho Chungyeon , Gamage Geethal Amila , Ren Zhifeng , Grunlan Jaime C.
Published: April 2021

Developing and understanding novel doping strategies for thermoelectric materials is imperative to efficiently convert waste into a useful voltage. One such method for improving the power factor of polymer nanocomposites is through salt doping. The cation size of a monovalent salt dopant was varied in a layer-by-layer (LbL)-assembled film composed of poly(diallyldimethylammonium chloride) (PDDA) and double-walled carbon nanotubes (DWNTs) stabilized by poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) [PEDOT:PSS]. Doping a 20 bilayer PDDA/DWNT-PEDOT:PSS film doped with 3 mmol CsCl yields the maximum power factor of 485 ± 29 μW m−1 K−2. This value was obtained through a five times increase in the electrical conductivity with a minimal decrease in the Seebeck coefficient relative to the undoped film. Cs+ is believed to more heavily dope the carbon nanotube network due to its relatively larger hydrophobicity, while also separating PEDOT from PSS due to charge screening. This study demonstrates the significance of the salt dopant identity, and the insight herein can likely be applied more broadly to improve a variety of organic thermoelectric materials.
Diffusion modeling of COVID-19 under lockdown
Authors: Serra Nicola , Di Carlo Paola , Rea Teresa , Sergi Consolato M.
Published: April 2021

Viral immune evasion by sequence variation is a significant barrier to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine design and coronavirus disease-2019 diffusion under lockdown are unpredictable with subsequent waves. Our group has developed a computational model rooted in physics to address this challenge, aiming to predict the fitness landscape of SARS-CoV-2 diffusion using a variant of the bidimensional Ising model (2DIMV) connected seasonally. The 2DIMV works in a closed system composed of limited interaction subjects and conditioned by only temperature changes. Markov chain Monte Carlo method shows that an increase in temperature implicates reduced virus diffusion and increased mobility, leading to increased virus diffusion.
Salt partitioning in ionized, thermo-responsive hydrogels: perspective to water desalination
Authors: Jangizehi Amir , Seiffert Sebastian
Published: April 2021

Charged hydrogels are capable of swelling in aqueous salt solutions, whereby part of the salt ions is repelled due to the presence of fixed charged groups inside the hydrogel. This effect creates a concentration gradient between the absorbed solution and the surrounding fluid known as salt partitioning, offering a potential for these materials to be employed to desalinate saltwater. If the charged hydrogels are thermo-sensitive as well, then the purer, absorbed solution can be recovered by shrinking the hydrogels upon temperature change. To tailor that potential in water-purification and desalination applications, the main parameters influencing the salt partitioning, the deswelling of the hydrogels, and the recovery of water must be understood. In this paper, we analyze these factors based on equations derived from the Donnan theory. In addition, hydrogels composed of N-isopropyl acrylamide and acrylic acid are synthesized, and their salt rejection efficiency in a model desalination experiment is studied. A comparison of the experimental and the theoretical results demonstrates that the charge density of the hydrogels at their equilibrium swelling and the degree of water recovery are two parameters controlling the salt rejection efficiency. These parameters are individually controlled by the content of the ionic groups and the degree of cross-linking of the gel polymer network. In addition, the prediction of the theory and the experimental results demonstrate that the salt rejection efficiency can be significantly improved if a second water recovery step is performed by a secondary increase in the temperature in the deswelling process.
Investigating the lubrication mechanism and stiffness of oil-based ferrofluids in spur gear drives
Authors: Huang Xingbao , Wang Weijun , Ding Lichao , Yang Bintang
Published: April 2021

Due to both liquid properties and ferromagnetic material characteristics, ferrofluids are developed as the favored component solvents. The art of investigating the lubrication mechanism of ferrofluids in spur gear drives is significant for improving the anti-wear of gear pairs and prolonging the service life. This paper proposes a mathematical model of oil-based ferrofluids lubrication and derives a system of governing equations. The tribology performances of oil-based ferrofluids are investigated in comparison with their counterparts of pure base oil. Furthermore, the effects of ferromagnetic particle size and bulk concentration on the tribological property and film stiffness of oil-based ferrofluids are studied. Finally, the influence of magnetic field intensity is analyzed and discussed. Results show that oil-based ferrofluids induce greater increases in film thickness and film normal stiffness in comparison with their counterparts of pure base oil; the decrease in ferromagnetic particle size causes considerable increases in film thickness and remarkable decreases in friction coefficient; the increase in bulk concentration induces a significant increase in film thickness and a remarkable decrease in friction coefficient, meanwhile the normal stiffness of ferrofluids film maintains stable; the increase in magnetic field intensity causes small increases in film thickness and small reductions in friction coefficient. Therefore, ferrofluids with ferromagnetic particles of small size and large bulk concentration are beneficial to lubrication and anti-wear of magnetized spur gear drives.
Scaling effects on the free surface backward facing step flow
Authors: Peltonen Petteri , Kanninen Pekka , Laurila Erkki , Vuorinen Ville
Published: April 2021

A set of large eddy simulations for the free surface backward facing step (FSBFS) are carried out to study wave formation behind the step. The volume-of-fluid ghost fluid method is employed to capture the free surface. Previous studies have indicated that the wave physics depend on the step draught-based Froude number (Fr). For small Fr, the rear face of the step (transom) becomes wet, while for large Fr, the wave separates smoothly from the transom. Close to a critical Fr separating wet and dry transoms, both conditions may occur. Here, we study wet, critical, and dry conditions based on the Fr classification with three different inflow boundary layer profiles (ReL=1,2,3×106). For Fr = 1.75 (wet conditions), we observe a weak dependence on the ReL. A proper orthogonal decomposition of the velocity field at Fr = 1.75 shows a coherent vortex street forming beneath the free surface. At Fr = 2.66 (critical conditions), we observe that an increase in the ReL results in a decrease in the wavelength and pronounced gas entrainment due to wave breaking. For Fr = 3.17 (dry conditions), we also observe shorter wavelength at increased ReL. Further, in the dry conditions, a breaking wave is noticed to occur at higher ReL, while breaking waves are not observed for the smallest studied ReL. Based on the results, we conclude that the wave shape for FSBFS cannot be characterized by the Froude number alone.
Lattice Boltzmann analysis for electro–thermo-convection with a melting boundary in horizontal concentric annuli
Authors: Lu Cai-Lei , Luo Kang , Zhou Pu-Cheng , Yi Hong-Liang
Published: April 2021

In this paper, we perform a two-dimensional numerical investigation into the electro–thermoconvection with a melting boundary in horizontal concentric annuli filled with a dielectric phase change material. The whole set of coupled equations is solved by lattice Boltzmann method: Navier–Stokes equations, electrohydrodynamics (EHD) equations, and the energy equation. It is found that there exist three regimes during melting with EHD, namely, diffusive regime, thermal convection regime, and electroconvection regime, and the augmentation of melting heat transfer is due to the radial electroconvective flow induced by Coulomb force in the third regime. Moreover, the continuous melting of solid leads to the dynamical transition between the different flow patterns of electro–thermo-convection, as well as the interesting evolutions of temperature and charge density distribution. In different regimes of melting, the liquid fraction fl and Nusselt number Nu follow different power laws. In detail, before the onset of radial flow motion, fl scales as Fo1/2 whereas Nu scales as fl−4/5 (Fo represents the Fourier number), and in the electroconvection dominated regime, we have fl ∼ Fo and Nu ∼ fl0.
Direct confirmation of the dopant site in indium-doped SrTiO3 photocatalyst via atomic-scale analytical transmission electron microscopy imaging
Authors: Kitta Mitsunori , Taguchi Noboru , Sudrajat Hanggara , Onishi Hiroshi
Published: April 2021

Confirming the dopant site of In3+-doped SrTiO3 (In–STO) is essential to reveal the mechanism of its photocatalytic activity. In a previous study, x-ray absorption spectroscopic analysis and theoretical investigations were performed to discuss the dopant site, and In3+–Ti4+ substitution was proposed. However, direct confirmation of the In3+ dopant site has not yet been reported. Here, we performed direct atomic-scale imaging of In–STO crystals via analytical transmission electron microscopy and revealed the dopant site based on real-space elemental mapping. The Ti and Sr sites in the SrTiO3 crystal lattice were well identified by atomic column elemental mapping using energy dispersive x-ray spectroscopy (EDS). The EDS signal of indium has a stronger intensity at the Ti site than at the Sr site, based on the total analysis of each Ti and Sr atomic column. By applying principal component analysis on the raw EDS spectral imaging data cube, the indium site was clearly imaged; it completely fit into the Ti atomic column positions. These results provide direct evidence of In–Ti substitution in In-STO photocatalysts.
Numerical analysis of two hollow drops simultaneously impacting a wet surface
Authors: Liu Xiaogang , Qu Yonglei , Wang Yanhua , Wang Meng , Wang Zhongyi , Sun Haiou
Published: April 2021

The impingement behaviors of two hollow drops or two continuous dense drops simultaneously impacting a thin liquid film were analyzed numerically using a three-dimensional coupled level-set and volume-of-fraction method. The findings indicate the formation of a counter-jet during the simultaneous impact of two hollow drops, whereas a relatively stable residual film is formed during the impingement of two continuous dense drops. This counter-jet generates heat-transfer blind spots in the case of simultaneous impact by hollow drops, leading to the easy splitting of the residual liquid film. The heat around the blind spot region is difficult to release due to flow stagnation and the squeezing of the initial cold liquid film to the symmetric point. These findings indicate that more focus should be placed on the uniformity of heat transfer in realistic applications involving drop impingement. Finally, analyses of pressure gradient and flow separation revealed the formation process of the counter-jet and central liquid sheet. The findings are valuable for guiding industrial technical practice.
Beyond 3 μm Dy3+/Er3+ co-doped ZBLAN fiber lasers pumped by 976 nm laser diode
Authors: Wang Junfeng , Zhu Xiushan , Norwood Robert A. , Peyghambarian Nasser
Published: April 2021

Dysprosium-erbium (Dy3+/Er3+) co-doped ZBLAN (ZrF4-BaF2-LaF3-AlF3-NaF) fiber lasers operating at 3.2–3.35 μm were demonstrated by pumping at the 980 nm Er3+ absorption band. A maximum output power of 260 mW at 3.27 μm with a slope efficiency of 5.73% was achieved with 3.6 m 0.25 mol. % Dy3+/4 mol. % Er3+ co-doped ZBLAN fiber. Lasers operating at 3.23 μm and 3.35 μm were also demonstrated with 2 m and 9 m gain fibers, respectively, but with lower slope efficiencies. Our experiments confirm the possibility of pumping the Dy3+/Er3+-doped ZBLAN fiber laser with a low-cost high efficiency diode laser at 976 nm.
Cell-induced confinement effects in soft tissue mechanics
Authors: Song Dawei , Shivers Jordan L. , MacKintosh Fred C. , Patteson Alison E. , Janmey Paul A.
Published: April 2021

The mechanical properties of tissues play a critical role in their normal and pathophysiological functions such as tissue development, aging, injury, and disease. Understanding tissue mechanics is important not only for designing realistic biomimetic materials for tissue engineering and drug testing but also for developing novel diagnostic techniques and medical interventions. Tissues are heterogeneous materials consisting of cells confined within extracellular matrices (ECMs), both of which derive their structural integrity, at least in part, from networks of biopolymers. However, the rheology of purified reconstituted biopolymer networks fails to explain many key aspects of tissue mechanics. Notably, purified networks typically soften under applied compression, whereas many soft tissues like liver, fat, and brain instead stiffen when compressed. While continuum models can readily capture this compression-stiffening behavior, the underlying mechanism is not fully understood. In this perspective paper, we discuss several recently proposed microscopic mechanisms that may explain compression stiffening of soft tissues. These mechanisms include (I) interactions between the ECM and volume-preserving inclusions that promote extension-dominated stiffening of fibrous ECMs when subject to uniform compression, (II) ECM interactions with rigid inclusions under non-uniform compression, (III) other internal physical constraints that cause compression stiffening of cells and ECMs, and (IV) propagation of compressive forces through jammed, compression-stiffening cells. We further identify a few of the many open problems in understanding the structure–function relationship of soft-tissue mechanics.
Wastewater monitoring for SARS-CoV-2
Authors: Donner Erica , Zamyadi Arash , Jex Aaron , Short Michael , Drigo Barbara , McCarthy David , Crosbie Nicholas , Ahmed Warish , Mueller Jochen , Thomas Kevin , Monis Paul , Keegan Alex , Ginige Maneesha , Hugenholtz Philip , Tyson Gene , Hill Kelly , Blackall Linda
Published: April 2021

Wastewater monitoring (WM) of SARS-CoV-2 from sewers was applied throughout the world early in the COVID-19 pandemic. Sharing of protocols and experiences in WM of SARS-CoV-2 by national and international researchers and practitioners has been vital to ensuring the sensitivity and specificity of the methods. WM has been a valuable adjunct to human clinical testing, and when positive results occur in sewage, community testing has been increased. WM findings allow public health officials to track and respond to the impacts of loosening lockdown restrictions, demonstrating when return to normal social activities might occur without a resurgence of rapid community transmission, and they are particularly useful in areas with low human case numbers and/or low clinical testing rates. New research is required to address several practical knowledge gaps, for example, sampling protocols, prediction of case prevalence from viral numbers by modelling, and determination of detection limits. Communication to the Australian public of WM of SARS-CoV-2 has been via interactive, visual dashboards. Once SARS-CoV-2 vaccinations are introduced, WM could help track the underlying circulation of the virus in the population, the spread of known variants and its future evolution.
Positive allosteric modulation of the mu-opioid receptor produces analgesia with reduced side effects
Authors: Kandasamy Ram , Hillhouse Todd M. , Livingston Kathryn E. , Kochan Kelsey E. , Meurice Claire , Eans Shainnel O. , Li Ming-Hua , White Andrew D. , Roques Bernard P. , McLaughlin Jay P. , Ingram Susan L. , Burford Neil T. , Alt Andrew , Traynor John R.
Published: April 2021

Significance

Opioids acting at the mu-opioid receptor (MOR) are the gold standard for pain relief. Unfortunately, these drugs have severe side effects, including addiction liability and respiratory depression. Consequently, safe pain management remains an unmet medical need. Here, we show that a positive allosteric modulator of MOR (a mu-PAM) does not directly activate MOR but produces analgesia in mouse models by enhancing the ability of endogenous opioid peptides, released in pain states, to activate MOR. Because the mu-PAM does not activate MOR directly, this raises the possibility of analgesia without the typical opioid side effects of addiction liability, respiratory depression, or constipation. The study provides proof of principle for mu-PAMs as an innovative and potentially safer approach to pain management.
Bacterial detection by NAIP/NLRC4 elicits prompt contractions of intestinal epithelial cell layers
Authors: Samperio Ventayol Pilar , Geiser Petra , Di Martino Maria Letizia , Florbrant Alexandra , Fattinger Stefan A. , Walder Naemi , Sima Eduardo , Shao Feng , Gekara Nelson O. , Sundbom Magnus , Hardt Wolf-Dietrich , Webb Dominic-Luc , Hellström Per M. , Eriksson Jens , Sellin Mikael E.
Published: April 2021

Significance

Contractile movements in the mammalian intestine typically rely on dedicated muscle cells. Here, we however show that untransformed intestinal epithelial cell layers initiate immediate focal contractions, affecting hundreds to thousands of epithelial cells, in response to bacterial infection. This epithelial contraction response occurs in the absence of other mucosal cell types. Instead, the epithelium itself senses the pathogen intrusion through a pattern recognition receptor complex—NAIP/NLRC4—and initiates actomyosin contractions that propagate across the epithelial layer. Within minutes, this response densifies the cell packing at infection sites and may prevent tissue disintegration during the subsequent stage of epithelial cell death and expulsion. Our results highlight a previously unappreciated dynamic behavior of intestinal epithelia.