bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of the elbow shape on the unsteady pressure field in decelerated swirling flows
Authors: Muntean S , Moş DC , Szakal RA , Bosioc AI , Susan-Resiga R 
Published: June 2021

Abstract
The induced flow instabilities are developed in the draft tube cone of the hydraulic turbines leading to the pressure fluctuations with negative impact on the mechanical components lifetime. Usually, two components (rotating and plunging) are discriminated in the unsteady pressure field induced by the swirling flow in the draft tube cone. The rotating component is associated with the precession motion of the flow instabilities (e.g. vortex rope) while the plunging part corresponds to the interaction of the swirling flow with the elbow. Extensive experimental investigations were carried out on Timisoara Swirl Generator test case in order to examine the influence of the elbow shape on the unsteady pressure field. Two elbow shapes (90° S shape elbow and 90° sharp heel) are selected to investigate their influence on the unsteady pressure field. Several geometrical configurations with pipe extensions placed between the cone and the elbow are considered for each elbow shape to determine the response of the hydraulic circuit. Two unsteady pressure signals located in opposite positions are measured on four levels placed along the cone. The Fourier spectra are determined for discriminated time series identifying both rotating and plunging components. Then, the ratio between the frequencies of the plunging and the rotating components is obtained for both elbow shapes in relation to the pipe length placed between the cone and the elbow. It is clear that the shape of the elbow and the distance between the cone and the elbow lead to a significant influence on the response of the hydraulic circuit.
Geometric parameters of influence on rotor stator interaction in radial hydraulic turbines
Authors: Nennemann B , Afara S , Monette C , Braun O 
Published: June 2021

Abstract
Numerical methods for the prediction of the hydraulic forcing from rotor stator interaction (RSI) in hydraulic turbines as well as the corresponding methods to calculate mechanical dynamic stresses are mature and well-established in the industry. The geometric factors influencing RSI are generally known, but little information is available on the quantification of these factors with respect to RSI forcing. We present relative quantifications of four geometric factors on RSI forcing expressed as dynamic blade torque. The factors are the blade leading edge lean, the radial distance between guide vane trailing and runner leading edges, the phase between adjacent runner channels as a function of number of guide vanes and blades, and finally the number of guide vanes independently of their effect on the phase. RSI pressure pulsations on the stator in the vane-less space between guide vanes and runner show a different tendency with the variation of the blade number compared to the dynamic blade torque. This indicates that dynamic pressure measurements in the vane-less space are not a good indicator for dynamic forcing on the runner blades.
Pump-turbine Rotor-Stator Interaction Induced Vibration: Problem Resolution and Experience
Authors: Zhang F , Lowys PY , Houdeline JB , Guo XD , Hong P , Laurant Y 
Published: June 2021

Abstract
Pressure pulsations induced by rotor-stator interaction (RSI) phenomenon are one of the major sources of excitation resulting in severe vibrations of pump-turbines and powerhouses. By now, many articles focus mainly on the RSI mechanism by methods of theoretical analysis, fluid-structure calculation and model test verification. There are few reports published on equipment and powerhouse vibrations induced by RSI. Therefore, in this paper we took a real RSI induced problem at Zhanghewan (ZHW) pumped storage power plant (PSPP). We employed frequency spectrum technology on signals of powerhouse vibrations and pressure pulsations in stable and transient processes, combined eigen-frequency measurement and numerical calculation of powerhouse localities, and then confirmed that partial powerhouse resonated with RSI induced pressure pulsation in the vaneless area (gap between guide vanes and runner blades). We statistically evaluated the relationship between the ratio of guide vane pitch diameter D0 to the high-pressure runner diameter D1 and vaneless area pressure pulsation from many PSPPs in China, and proposed solutions that new runner should use. The runner alteration work was successful. Model tests and field measurements show that vaneless pressure pulsation decreases and the powerhouse shows acceptable vibration levels. Many experiences were accumulated during this work, including that from an engineering perspective by enlarging the vaneless area it is possible to lower RSI induced pressure vibrations. Also, much attention should be paid on local anti-vibration calculations in the powerhouse designing period. Our research and review provide a new perspective for designing, refurbishing, rehabilitating of pump-turbines.
Research on Modeling and Control Strategy of Hydraulic Turbine Governing System Based on Improved Genetic Algorithm
Authors: Jiang Xiaoping , Chen Xiaofei , Wang Zhengwei 
Published: June 2021

Abstract
The mathematical model of the turbine governing system is obtained by modeling analysis. Under the premise of this model, the improved genetic algorithm is used to optimize the parameters in the parameter identification of the turbine governing system, and the high-precision parameter identification of the turbine governing system is realized, and an accurate mathematical model of the turbine governing system is established. In terms of control strategy, through theoretical analysis of conventional PID, fuzzy control and genetic algorithm, a fuzzy PID control based on genetic algorithm optimization (GA-fuzzy PID) is designed to realize the adaptive and adjustment ability of PID control. Compared with the traditional PID control, it has better control effect, and it is easier to make the turbine adjustment system achieve stability, quickness and accuracy.
Comparisons of vortical flow and cavitation inside a Francis turbine with different draft tubes
Authors: Geng Chen , Zhang Ruizhi , Tsujimoto Yoshinobu , Nishi Michihiro , Luo Xianwu 
Published: June 2021

Abstract
It is well known that strong pressure fluctuation will occur in the draft tube of a Francis turbine operated under part-load operation. The pressure fluctuation is usually due to the vortex rope as well as cavitation. However, the vortical flow and pressure field are dependent on the geometry of draft tube of Francis turbine. In this study, hydraulic performance and pressure fluctuation have been tested for a model Francis turbine. The internal flow for the turbine is investigated numerically. It is confirmed that the numerical results predict reasonably the hydraulic performance and the pressure fluctuation due to vortex rope at part-load operation.
For a better understanding of the vortical flow in the model turbine, a conical draft tube is used instead of the conventional elbow draft tube. The vorticity transport equation is applied to analyze the vortex evolution inside Francis turbine based on the unsteady flow simulation. The flow mechanism of the vortex rope and pressure fluctuation with different draft tubes is discussed. It is shown that both cavitation and the bending structure influence the vortex rope, which will cause a significant difference in the distribution of pressure fluctuation.
Evaluation of the effects of shear stress on crucian carps passing through turbines
Authors: Meng Long , Wang Wanpeng , Li Tieyou , Liao Cuilin , Zhao Lice , Chen Ying 
Published: June 2021

Abstract
Turbine-passed fish is inevitably exposed to one or more physical forces, such as fast pressure change, blade strikes and shear stress, which can lead to injury or fatalities. The injury mechanisms of these forces to fish and related criteria are necessary for fish-friendly-turbine design and optimization. The effects of shear stress on crucian carps are studied in a specially designed experimental system. Crucian carps are exposed to a submerged water jet at velocities ranging from 5m/s to 20m/s. High-speed, high-resolution digital videos of the exposure process was recorded for motion-tracking analysis. Fish sizes, flow directions and water jet velocities are key factors considered during the tests. Injury rate, degree of severity, site of trauma, and death rate of crucian carps after tests were studied according to repeated tests with different factors. Injuries such as shedding of fish scales, tearing of gill cover, laceration of eyeballs are observed at different water jet velocity and with different size of crucian carps. The injury mechanisms were concluded and design criteria for fish-friendly-turbine are proposed according to the study.
Numerical Simulation and Research of the Axial Flow Fish-friendly Turbine in Plateau Area
Authors: Yang Chunxia , Xu Ding’e , Zhang Qianxu , Zhu Shuangju , Zhao Lei 
Published: June 2021

Abstract
Based on the design methods of fish friendly hydraulic turbines at home and abroad and traditional hydraulic turbines, this paper designs an axial flow fish friendly hydraulic turbine in plateau area by using Unigraphics NX. The steady-state simulation of the turbine is carried out by fluent, and the energy characteristics of the three blade runner are analyzed. Through the transient computation, the pressure fluctuation characteristics in the leafless area of the turbine with guide vane opening of 18.2° and 14.2° are studied, and the fish passing characteristics are analyzed. Compared with the evaluation criteria of fish friendly water turbine, the variation rate of pressure obtained is less than 550.3kpa/s, which meets the design criteria of fish friendly water turbine and basically meets the demand of fish passing down the dam.
Novel Hydraulic Turbine Governing System Based on Digital Cartridge Valve Technology
Authors: Wang Cong , Wang De-kuan , Zhang Jian-ming 
Published: June 2021

Abstract
Digital cartridge governor, as a new direction of hydraulic turbine governor control, has been applied in engineering practice, but its relative theory and engineering application research are few. The engineering application of novel hydraulic turbine governing system based on digital cartridge valve technology is taken as the research object in this paper. Combining theory with engineering application, control strategies and rules of the digital cartridge turbine governor in key concerns of engineering applications such as closed-loop power regulation, isolated grid operation, the low-frequency de-excitation and the over-speed of load rejection of bulb turbine units are discussed, and engineering applications of digital cartridge turbine governor are summarized, which can be used for reference to solve some problems in the application of governor.
Botulinum Toxin to Improve Lower Blepharoplasty Scar: A Double-Blinded, Randomized, Vehicle-Controlled Clinical Trial
Authors: Huang Yau-Li , Wallace Christopher Glenn , Hsiao Yen-Chang , Lee Mei-Ching , Huang Jung-Ju , Chang Frank Chun-Shin , Chen Zung-Chung , Hu Sindy , Chen Jyh-Ping 
Published: June 2021

Abstract

Background
Lower blepharoplasty is a common cosmetic operation that relies on minimal postoperative scarring, but Asian patients are at higher risk than Caucasians for hypertrophic and/or widened scars. Botulinum toxin type A (BTX) injections are widely employed to alleviate dynamic facial rhytids and also can improve scar quality by reducing scar tension. The authors assessed whether simultaneous transcutaneous lower blepharoplasty and BTX injections could improve subciliary scar quality.

Objectives
The objective of this study was to assess whether simultaneous transcutaneous lower blepharoplasty and BTX injections could improve subciliary scar quality.

Methods
This is a prospective, randomized, vehicle-controlled, double-blinded clinical trial. Between May 2015 and May 2018, 40 adults who underwent bilateral transcutaneous lower blepharoplasties were randomized to receive BTX (n = 20) or vehicle (normal saline; n = 20) injections into the lateral orbicularis oculi muscle immediately after wound closure. Vancouver Scar Scale, Visual Analogue Scale, and photographic scar width measurements at 3 reference points were recorded at the final clinical follow-up.

Results
Thirty-seven patients completed the trial. Vancouver Scar Scale and Visual Analogue Scale scores in the experimental and vehicle control groups were similar, but scar widths in the experimental group at all measured points were significantly narrower than in the vehicle control group (P &lt; 0.001, P = 0.027, and P &lt; 0.001 at each measured point, respectively).

Conclusions
Transcutaneous lower blepharoplasty scars in Asians can be significantly narrowed by simultaneous BTX injections without additional complications.

Level of Evidence 4
COSMIC Cancer Gene Census 3D database: understanding the impacts of mutations on cancer targets
Authors: Alsulami Ali F , Torres Pedro H M , Moghul Ismail , Arif Sheikh Mohammed , Chaplin Amanda K , Vedithi Sundeep Chaitanya , Blundell Tom L 
Published: June 2021

AbstractMutations in hallmark genes are believed to be the main drivers of cancer progression. These mutations are reported in the Catalogue of Somatic Mutations in Cancer (COSMIC). Structural appreciation of where these mutations appear, in protein–protein interfaces, active sites or deoxyribonucleic acid (DNA) interfaces, and predicting the impacts of these mutations using a variety of computational tools are crucial for successful drug discovery and development. Currently, there are 723 genes presented in the COSMIC Cancer Gene Census. Due to the complexity of the gene products, structures of only 87 genes have been solved experimentally with structural coverage between 90% and 100%. Here, we present a comprehensive, user-friendly, web interface (https://cancer-3d.com/) of 714 modelled cancer-related genes, including homo-oligomers, hetero-oligomers, transmembrane proteins and complexes with DNA, ribonucleic acid, ligands and co-factors. Using SDM and mCSM software, we have predicted the impacts of reported mutations on protein stability, protein–protein interfaces affinity and protein–nucleic acid complexes affinity. Furthermore, we also predicted intrinsically disordered regions using DISOPRED3.
Markets as ecological networks: inferring interactions and identifying communities
Authors: Emary Clive , Fort Hugo 
Published: June 2021

AbstractFinancial markets are paradigmatic examples of complex systems and have been compared to ecological networks in which different species (firms) interact and co-evolve. A central object governing species dynamics in ecology is the community matrix, whose elements are closely related to pairwise interspecific interaction coefficients. Using this ecological analogy we propose a method, based on the Maximum Entropy (MaxEnt) principle, that allows us to infer candidates for an economic community matrix from time series data of market values. To assess the usefulness of this picture, we construct community matrices for a set of companies belonging to the Fortune 500 list and perform a community analysis on the resultant networks. This analysis shows these networks to strongly reflect the known industry groupings of the firms. We conclude therefore that our community matrices capture non-trivial information about the interaction of firms, not immediately apparent from the covariance of market values. We anticipate our approach being useful in elucidating further aspects of market structure, as well as forming the basis of forecasting market dynamics.
Spatiotemporal and seasonal dynamics in the microbial communities of a landfill-leachate contaminated aquifer
Authors: Abiriga Daniel , Jenkins Andrew , Alfsnes Kristian , Vestgarden Live Semb , Klempe Harald 
Published: June 2021

ABSTRACT
The microbiome of an aquifer contaminated by landfill leachate and undergoing intrinsic remediation was characterised using 16S rRNA metabarcoding. The archaeal/bacterial V3–V4 hypervariable region of the 16S rRNA gene was sequenced using Illumina MiSeq, and multivariate statistics were applied to make inferences. Results indicate that the aquifer recharge and aquifer sediment samples harbour different microbial communities compared to the groundwater samples. While Proteobacteria dominated both the recharge and groundwater samples, Acidobacteria dominated the aquifer sediment. The most abundant genera detected from the contaminated aquifer were Polynucleobacter, Rhodoferax, Pedobacter, Brevundimonas, Pseudomonas, Undibacterium, Sulfurifustis, Janthinobacterium, Rhodanobacter, Methylobacter and Aquabacterium. The result also shows that the microbial communities of the groundwater varied spatially, seasonally and interannually, although the interannual variation was significant for only one of the wells. Variation partitioning analysis indicates that water chemistry and well distance are intercorrelated and they jointly accounted for most of the variation in microbial composition. This implies that the species composition and water chemistry characteristics have a similar spatial structuring, presumably caused by the landfill leachate plume. The study improves our understanding of the dynamics in subsurface microbial communities in space and time.
Effects of Synonymous Mutations beyond Codon Bias: The Evidence for Adaptive Synonymous Substitutions from Microbial Evolution Experiments
Authors: Bailey Susan F , Alonso Morales Luz Angela , Kassen Rees 
Published: June 2021

AbstractSynonymous mutations are often assumed to be neutral with respect to fitness because they do not alter the encoded amino acid and so cannot be “seen” by natural selection. Yet a growing body of evidence suggests that synonymous mutations can have fitness effects that drive adaptive evolution through their impacts on gene expression and protein folding. Here, we review what microbial experiments have taught us about the contribution of synonymous mutations to adaptation. A survey of site-directed mutagenesis experiments reveals the distributions of fitness effects for nonsynonymous and synonymous mutations are more similar, especially for beneficial mutations, than expected if all synonymous mutations were neutral, suggesting they should drive adaptive evolution more often than is typically observed. A review of experimental evolution studies where synonymous mutations have contributed to adaptation shows they can impact fitness through a range of mechanisms including the creation of illicit RNA polymerase binding sites impacting transcription and changes to mRNA folding stability that modulate translation. We suggest that clonal interference in evolving microbial populations may be the reason synonymous mutations play a smaller role in adaptive evolution than expected based on their observed fitness effects. We finish by discussing the impacts of falsely assuming synonymous mutations are neutral and discuss directions for future work exploring the role of synonymous mutations in adaptive evolution.
The law of the global economy and the spectre of inequality
Authors: Venzke Ingo 
Published: June 2021

Abstract
Drawing on my inaugural lecture, I argue that the spectre of inequality haunts international law. The presence of the spectre first of all draws attention to what is rotten in the global economic order: how the law of the global economy has contributed to high levels of inequality while, at the same time, abdicating responsibility for it. Second, like all spectres, international law’s spectre of inequality is animated by a spirit, the spirit of social justice. It points to forsaken paths, lost memories and conjures up past possibilities that were not realized. Third, the spectre endures unless we give in and break with current repetitions. It directs those in search of progressive change towards productive contradictions within global order. Those contradictions are indeed carriers of hope. They offer reason to believe that the future is open. Engaging with the spectre of inequality in international law turns out to be much less daunting than failing to do so.
A theoretical model of the near-surface shear layer of the Sun
Authors: Jha Bibhuti Kumar , Choudhuri Arnab Rai 
Published: June 2021

ABSTRACT
The Sun has a near-surface shear layer (NSSL), within which the angular velocity decreases rapidly with radius. We provide an explanation of this layer based on the thermal wind balance equation. Since convective motions are not affected by solar rotation in the top layer of the convection zone, we argue that the temperature falls at the same rate at all latitudes in this layer. This makes the thermal wind term very large in this layer and the centrifugal term has also to become very large to balance it, giving rise to the NSSL. From the values of differential rotation Ω(r &lt; rc, θ) at radii less than a radius rc, we can calculate the temperature difference ΔT(r, θ) with respect to the standard solar model at different points of the convection zone by making use of the thermal wind balance equation. Then, we again use this equation in the top layer to calculate Ω(r &gt; rc, θ) there from ΔT(r, θ). We carry on this exercise using both an analytical expression of the differential rotation and the actual data provided by helioseismology. We find that our theoretical results of the NSSL match the observational data reasonably well for rc ≈ 0.96R⊙, giving an estimate of the radius till which the convective motions are affected by the solar rotation.
“Disruptive Technology” in Spine Surgery and Education: Virtual and Augmented Reality
Authors: Godzik Jakub , Farber S Harrison , Urakov Timur , Steinberger Jeremy , Knipscher Liza J , Ehredt Ryan B , Tumialán Luis M , Uribe Juan S 
Published: June 2021

Abstract

BACKGROUND
Technological advancements are the drivers of modern-day spine care. With the growing pressure to deliver faster and better care, surgical-assist technology is needed to harness computing power and enable the surgeon to improve outcomes. Virtual reality (VR) and augmented reality (AR) represent the pinnacle of emerging technology, not only to deliver higher quality education through simulated care, but also to provide valuable intraoperative information to assist in more efficient and more precise surgeries.

OBJECTIVE
To describe how the disruptive technologies of VR and AR interface in spine surgery and education.

METHODS
We review the relevance of VR and AR technologies in spine care, and describe the feasibility and limitations of the technologies.

RESULTS
We discuss potential future applications, and provide a case study demonstrating the feasibility of a VR program for neurosurgical spine education.

CONCLUSION
Initial experiences with VR and AR technologies demonstrate their applicability and ease of implementation. However, further prospective studies through multi-institutional and industry-academic partnerships are necessary to solidify the future of VR and AR in spine surgery education and clinical practice.