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Wind-induced instabilities and monitoring of wind turbine

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Earthquake Engineering and Engineering Vibration 2019年第2期18卷 475-485页

作者： Isaac Wait Zhaohui (Joey) Yang Gang Chen benjamin Still College of IT & Engineering Marshall University Department of Civil Engineering University of Alaska Anchorage

This paper presents real-time monitoring data and analysis results of the non-stationary vibrations of an operational wind turbine. The advanced time-frequency spectrum analysis reveals varied non-stationary vibrations with timevarying frequencies, which are correlated with certain system natural modes characterized by finite element analysis. Under the effects of strong wind load, the wind turbine system exhibits certain resonances due to blade passing excitations. The system also exhibits certain instabilities due to the coupling of the tower bending modes and blade flapwise mode with blade passing excitations under the variation of wind speed. An analytical model is used to elaborate the non-stationary and instability phenomena observed in experimental results. The properties of the nonlinear instabilities are evaluated by using Lyapunov exponent estimation.

关键词： wind turbine condition monitoring non-stationary vibrations instabilities whirl modes warm permafrost

Effect of thermo-mechanical conditions during constrained friction processing on the particle refinement of AM50 Mg-alloy phases

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Journal of Magnesium and Alloys 2024年第6期12卷 2298-2311页

作者： Camila Caroline de Castro AndréMartins Neves benjamin Klusemann Helmholtz-Zentrum Hereon Institute of Material and Process DesignSolid-State Materials Processing21502 GeesthachtGermany Helmholtz-Zentrum Hereon Institute of Hydrogen TechnologySystem Design for Mobility21502 GeesthachtGermany Helmut Schmidt University/University of the german Federal Armed Forces Hamburg Department of Mechanical and Civil Engineering22043 HamburgGermany Leuphana University Lüneburg Institute for Production Technology and Systems21335 LüneburgGermany

Constrained Friction Processing(CFP)is a novel solid-state processing technique suitable for lightweight materials,such Mg-and *** technique enables grain size refinement to fine or even ultrafine *** this study,the effect of CFP on the microstructural refinement of AM50 rods is investigated in terms of particle size and morphology of the eutectic and secondary phases originally present in the base material,in particular the eutecticβ-Mg_(17)Al_(12)and Al-Mn *** that purpose,as-cast and solution heat-treated base material and processed samples were *** Al_(8)Mn_(5) intermetallic phase was identified as the main secondary phase present in all samples before and after the processing.A notorious refinement of these particles was observed,starting from particles with an average equivalent length of a few micrometers to around 560 nm after the *** refinement of the secondary phase refinement is attributed to a mechanism analogous to the attrition comminution,where the combination of temperature increase and shearing of the material enables the continuous breaking of the brittle intermetallic particles into smaller *** for the eutectic phase,the results indicate the presence of the partially divorcedβ-Mg_(17)Al_(12)particles exclusively in the as-cast base material,indicating that no further phase transformations regarding the eutectic phase,such as dynamic precipitation,occurred after the *** the case of the processed as-cast material analyzed after the CFP,the thermal energy generated during the processing led to temperature values above the solvus limit of the eutectic phase,which associated with the mechanical breakage of the particles,enabled the complete dissolution of this ***,CFP was successfully demonstrated to promote an extensive microstructure refinement in multiple aspects,in terms of grain sizes of theα-Mg phase and presence and morphology of the Al-Mn and eutecticβ-Mg_(17)Al_(12).

关键词： Constrained friction processing AM50 Refill friction stir spot welding Extrusion β-Mg_(17)Al_(12) Al-Mn phases

Varicella zoster virus vaccines: potential complications and possible improvements

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Virologica Sinica 2014年第5期29卷 265-273页

作者： benjamin Silver Hua Zhu Department of Microbiology Biochemistry & Molecular Genetics Rutgers New Jersey Medical School

Varicella zoster virus(VZV) is the causative agent of varicella(chicken pox) and herpes zoster(shingles). After primary infection, the virus remains latent in sensory ganglia, and reactivates upon weakening of the cellular immune system due to various conditions, erupting from sensory neurons and infecting the corresponding skin tissue. The current varicella vaccine(v-Oka) is highly attenuated in the skin, yet retains its neurovirulence and may reactivate and damage sensory neurons. The reactivation is sometimes associated with postherpetic neuralgia(PHN), a severe pain along the affected sensory nerves that can linger for years, even after the herpetic rash resolves. In addition to the older population that develops a secondary infection resulting in herpes zoster, childhood breakthrough herpes zoster affects a small population of vaccinated children. There is a great need for a neuro-attenuated vaccine that would prevent not only the varicella manifestation, but, more importantly, any establishment of latency, and therefore herpes zoster. The development of a genetically-defined live-attenuated VZV vaccine that prevents neuronal and latent infection, in addition to primary varicella, is imperative for eventual eradication of VZV, and, if fully understood, has vast implications for many related herpesviruses and other viruses with similar pathogenic mechanisms.

关键词： varicella zoster virus herpesvirus vaccine neurovirulence neuro-attenuation latency latent infection herpes zoster shingles chicken pox ORF7

Analysis of synthetic parameters for coating aluminum powders with phenyltriethoxysilane coupling agent and their effects on powder flow behavior

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Particuology 2024年第7期90卷 412-417页

作者： Lillian M.Mawby Bellamarie Ludwig benjamin J.Lear Department of Chemistry The Pennsylvania State UniversityUniversity ParkPA16802USA Applied Research Laboratory The Pennsylvania State UniversityUniversity ParkPA16802USA

Though silanization of aluminum powder is currently used to improve its flow properties,for use as an alternative fuel source,there are a wide range of experimental parameters for the process and not all of them have been thoroughly *** this is complete,it is unknown if the process is optimized in terms of time,efficiency,and ***,we report on a study into the effects of changes in humidity,degree of agitation,reaction temperature,and curing time upon the deposition of phenyl triethoxysilane into 20μm(d50)aluminum *** confirm the deposition of the coating via diffuse reflectance infrared spectroscopy and x-ray photoelectron *** then characterize the coated particles using apparent density measurements and Carney flow *** analysis of variance,we find that,of the parameters explored,only changes in cure time and reaction temperature provide meaningful changes to the apparent density,while none of our parameters produced statistically significant changes in Carney flow ***,we conclude that,when optimizing silanization of aluminum particles,environmental control of humidity is unneeded and that the reaction can be run with minimal *** ability to largely ignore these parameters is a benefit to large-scale processing.

关键词： Aluminum powder Silane Fluidization Apparent density Carney flow

Endoscopic full-thickness resection: current status

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World Journal of Gastroenterology 2015年第31期21卷 9273-9285页

作者： Arthur Schmidt benjamin Meier Karel Caca Department of Gastroenterology and Oncology

Conventional endoscopic resection techniques such as endoscopic mucosal resection or endoscopic submucosal dissection are powerful tools for treatment of gastrointestinal neoplasms. However,those techniques are restricted to superficial layers of the gastrointestinal wall. Endoscopic full-thickness resection(EFTR) is an evolving technique,which is just about to enter clinical routine. It is not only a powerful tool for diagnostic tissue acquisition but also has the potential to spare surgical therapy in selected patients. This review will give an overview about current EFTR techniques and devices.

关键词： Endoscopic full-thickness resection Over-the-scope

Generation of meaningful synthetic sensor data—Evaluated with a reliable transferability methodology

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Energy and AI 2024年第1期15卷 248-264页

作者： Michael Meiser benjamin Duppe Ingo Zinnikus Deutsches Forschungszentrum für künstliche Intelligenz(DFKI) Stuhlsatzenhausweg 3Saarbrücken66123SaarlandGermany

As households are equipped with smart meters,supervised Machine Learning(ML)models and especially Non-Intrusive Load Monitoring(NILM)disaggregation algorithms are becoming increasingly *** be robust,these models require a large amount of data,which is difficult to ***,the generation of meaningful synthetic data is becoming more *** use a simulation framework to generate multiple datasets using different techniques and evaluate their quality statistically by measuring the performance of NILM models for *** demonstrate that the method of data generation is crucial to train ML models in a meaningful *** experiments conducted reveal that adding noise to the synthetic smart meter data is essential to train robust NILM models for *** best results are obtained when this noise is derived from unknown appliances for which no ground truth data is *** we observed that NILM models can provide unstable results,we develop a reliable evaluation methodology,based on Cochran’s sample ***,we compare the quality of the generated synthetic data with real data and observe that multiple NILM models trained on synthetic data perform significantly better than those trained on real data.

关键词： Smart home Synthetic sensor data Energy data Transfer learning Evaluation methodology Machine learning Neural networks NILM Seq2point WindowGRU DAE Seq2seq RNN

Emerging wearable technology applications in gastroenterology:A review of the literature

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World Journal of Gastroenterology 2021年第12期27卷 1149-1160页

作者： Kimberly PL Chong benjamin KP Woo College of Osteopathic Medicine Western University of Health SciencesPomonaCA 91766United States Department of Psychiatry and Biobehavioral Sciences Olive View-University of California Los Angeles Medical CenterSylmarCA 91342United States

The field of gastroenterology has recently seen a surge in wearable technology to monitor physical activity,sleep quality,pain,and even gut *** past decade has seen the emergence of wearable devices including Fitbit,Apple Watch,AbStats,and ingestible *** this review,we discuss current and future devices designed to measure sweat biomarkers,steps taken,sleep efficiency,gastric electrical activity,stomach pH,and intestinal *** also summarize several clinical studies to better understand wearable devices so that we may assess their potential benefit in improving healthcare while also weighing the challenges that must be addressed.

关键词： Wearable technology Wearables Ingestibles Smartphone Remote patient monitoring Gastroenterology

Binocular treatment of amblyopia:from the laboratory to clinical trials

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Annals of Eye Science 2019年第1期4卷 57-59页

作者： benjamin Thompson School of Optometry and Vision Science University of WaterlooWaterlooCanada

Over the last 10 years,numerous psychophysical studies have indicated that binocular mechanisms are structurally intact but functionally suppressed in amblyopia(1-8).Many of these studies have used a contrast balancing approach,whereby the contribution of each eye to binocular vision is equated or“balanced”by presenting higher contrast stimulus elements to the amblyopic eye than the fellow eye(6).Using this approach,the strength of suppression can be quantified by measuring the magnitude of interocular contrast difference required for normal binocular *** suppression strength has been correlated with other clinical measures,stronger suppression has been associated with worse stereoacuity and worse amblyopic eye visual acuity indicting a link between the monocular and binocular deficits in amblyopia(5,7).

关键词： strength suppression clinical

Multimodal Adaptive Identity-Recognition Algorithm Fused with Gait Perception

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Big Data Mining and Analytics 2021年第4期4卷 223-232页

作者： Changjie Wang Zhihua Li benjamin Sarpong Department of Computer Science and Technology School of Artificial Intelligence and Computer ScienceJiangnan UniversityWuxi 214122China

Identity-recognition technologies require assistive equipment,whereas they are poor in recognition accuracy and *** overcome this deficiency,this paper proposes several gait feature identification ***,in combination with the collected gait information of individuals from triaxial accelerometers on smartphones,the collected information is preprocessed,and multimodal fusion is used with the existing standard datasets to yield a multimodal synthetic dataset;then,with the multimodal characteristics of the collected biological gait information,a Convolutional Neural Network based Gait Recognition(CNN-GR)model and the related scheme for the multimodal features are developed;at last,regarding the proposed CNN-GR model and scheme,a unimodal gait feature identity single-gait feature identification algorithm and a multimodal gait feature fusion identity multimodal gait information algorithm are *** results show that the proposed algorithms perform well in recognition accuracy,the confusion matrix,and the kappa statistic,and they have better recognition scores and robustness than the compared algorithms;thus,the proposed algorithm has prominent promise in practice.

关键词： gait recognition person identification deep learning multimodal feature fusion