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Robust Machine Learning Mapping of sEMG Signals to Future Actuator Commands in Biomechatronic Devices

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Journal of Bionic Engineering 2024年第1期21卷 270-287页

作者： Ali nasr Sydney Bell Rachel L.Whittaker Clark R.Dickerson John McPhee Systems Design Engineering University of WaterlooWaterloo N2L 3G1Canada Kinesiology and Health Sciences University of WaterlooWaterloo N2L3G3Canada

A machine learning model for regression of interrupted Surface Electromyography(sEMG)signals to future control-oriented signals(e.g.,robot’s joint angle and assistive torque)of an active biomechatronic device for high-level myoelectric-based hierarchical control is proposed.A Recurrent Neural Network(RNN)was trained using output data,initially obtained from offline optimization of the biomechatronic(human–robot)device and shifted by the prediction *** input of the RNN consisted of interrupted sEMG signals(to mimic signal disconnections)and previous kinematic signals of the assistive *** RNN with a 0.1-s prediction horizon could predict the control-oriented joint angle and assistive torque with 92%and 86.5%regression accuracy,respectively,for the test *** proposed approach permits a fast,predictive,and direct estimation of control-oriented signals instead of an iterative process that optimizes assistive torque in the inverse dynamic simulation of a multibody human–robot *** with these interrupted input signals significantly improves the regression accuracy in the case of sEMG signal *** Robust Predictive Control-oriented Machine Learning(Robust-MuscleNET)model can support volitional high-level myoelectric-based control of biomechatronic devices,such as exoskeletons,prostheses,and assistive/resistive *** work should study the application to prosthesis control as well as the repeatability of the high-level controller with electrode *** low-level hierarchical controller that manages the human–robot interaction,the assistance/resistance strategy,and the actuator coordination should also be studied.

关键词： Myoelectric-based control-Surface electromyography Machine learning Multibody system dynamics Exoskeleton Bionic

Improvement of corrosion performance of 316L stainless steel via PVTMS/henna thin film

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Progress in Natural Science:Materials International 2012年第5期22卷 392-400页

作者： Abolfazl Motalebi Mojtaba.nasr-Esfahani Rania Ali Mehdi Pourriahi Department of Materials Science and Engineering Najafabad BranchIslamic Azad UniversityIsfahan 85141-43131Iran Department of Materials Science Institute for Surface Science and Corrosion(LKO)University of Erlangen-NurembergMartensstrasse 7D-91058 ErlangenGermany

Metallic materials are the most used materials as orthopedic or dental implants due to their excellent mechanical *** they are not able to create a natural bonding with the mineralized bone and occasionally suffer localized *** work describes the electrochemical behavior of a hybrid sol-gel thin film with the addition of green *** films enhance the ability of the implant to make a union with the existing bone and improve its resistance to aggressive *** ethanol solution of the polymerized vinyltrimethoxysilane(PVTMS) was mixed with an aqueous solution of henna extract(Lawsonia inermis) and refluxed to give homogeneous *** hybrid PVTMS/henna thin films were deposited on the stainless steel 316L by *** morphology,composition and adhesion of hybrid sol-gel coatings have been examined by SEM,EDX and pull-off test,*** of high additive concentrations(0.1%) did not disorganize the sol-gel *** pull-off test recorded a mean coating-substrate bonding strength larger than 20.6 MPa for the hybrid sol-gel *** effect of henna extract,with various added concentrations from 0.012% to 0.1%,on the anticorrosion properties of sol-gel films have been characterized by electrochemical impedance spectroscopy(EIS) and potentiodynamic polarization tests in simulated body fluid(SBF) solution and has been compared to the bare *** extract additions(0.05%) have significantly increased the corrosion protection of the sol-gel thin film to higher than 90%.The in vitro bioactivity of prepared films indicates that hydroxyapatite nuclei can form and grow on the surface of the doped sol-gel thin *** present study shows that due to their excellent anticorrosion properties,bioactivity and bonding strength to substrate,doped sol-gel thin films are practical hybrid films in biomedical applications.

关键词： Green corrosion inhibitor Henna extract Sol-gel coating Corrosion 316L

CeO_2掺杂的Mn/Al催化剂的物化、表面及催化性能(英文)

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催化学报 2008年第8期29卷 687-695页

作者： nasr-Allah M.DERAZ Physical Chemistry Department Laboratory of Surface Chemistry and CatalysisNational Research Center

Pure and CeO2-doped Mn/Al mixed oxides were prepared by the wet impregnation method using finely powdered alumina,manganese,and cerium *** physicochemical,surface,and catalytic properties of the thermally treated solids(at 500,800,and 900 ℃) were investigated using XRD,nitrogen adsorption at-196 ℃,and hydrogen peroxide decomposition in an aqueous solution at 30 -50 ℃.The Mn oxidation state changed from Mn4+ to Mn2+ on increasing the calcination *** were two unique features associated with CeO2 that are of *** first was that it favored the dispersion of manganese oxides deposited on the γ-Al2O3 catalyst calcined at 500 ℃.The second was that it enhanced the formation of Mn3O4 species from Mn2O3 deposited initially on the alumina support calcined at 800 and 900 ℃.Consequently,the specific surface area of the Mn/Al mixed oxides calcined at 500 ℃ was increased by increasing the amount of dopant *** opposite effect was observed by increasing the calcination temperature from 500 to 900 ℃.The doping followed by calcination at different temperatures brought about an increase in the catalytic activity of mixed *** did not modify the mechanism of the catalyzed reaction but changed the number of catalytically active sites without changing the nature of these sites.

关键词：二氧化铈物理化学性质催化性氧化铝

Pollen morphology of the family Cistaceae in Egypt and its systematic significance

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Journal of Systematics and Evolution 2011年第4期49卷 362-371页

作者： nasr M.HASSAN Botany Department Faculty of ScienceAssiut University

The pollen morphology of 11 species (including two subspecies and two varieties) belonging to two genera (Helianthemum and Fumana) of the family Cistaceae in Egypt was studied using light and scanning electron *** grains of the studied taxa were found to be radially symmetrical and *** size,shape,apertures,and exine ornamentation characteristics were valuable parameters among the studied *** largest pollen size was recorded in *** and the smallest one observed in *** ***- *** shape in the Egyptian taxa varied from (sub-)prolate to prolate spheroidal,but *** is different in having sub-oblate *** pollen data confirm that *** and *** are very closely related *** sculpture was useful in distinguishing between *** *** and *** *** main pollen types of exine ornamentation were recognized: retipilate;reticulate to verrucate;and *** on palynological data,a key for the studied taxa is suggested.

关键词： Cistaceae exine sculpture palynology scanning electron microscopy.

Generation of high-quality electron beams by ionization injection in a single acceleration stage

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High Power Laser Science and Engineering 2016年第3期4卷 39-45页

作者： nasr A.M.Hafz Song Li Guangyu Li Mohammad Mirzaie Ming Zeng Jie Zhang Key Laboratory for Laser Plasmas(MOE) and Department of Physics and Astronomy Collaborative Innovation Center of IFSAShanghai Jiao Tong University

Ionization-induced electron injection in laser wakefield accelerators, which was recently proposed to lower the laser intensity threshold for electron trapping into the wake wave, has the drawback of generating electron beams with large and continuous energy spreads, severely limiting their future applications. Complex target designs based on separating the electron trapping and acceleration stages were proposed as the only way for getting small energy-spread electron beams. Here, based on the self-truncated ionization-injection concept which requires the use of unmatched laser–plasma parameters and by using tens of TW laser pulses focused onto a gas jet of helium mixed with low concentrations of nitrogen, we demonstrate single-stage laser wakefield acceleration of multi-hundred MeV electron bunches with energy spreads of a few percent. The experimental results are verified by PIC simulations.

关键词： ionization injection laser–plasma acceleration PIC simulations self-truncation wakefield

Quantitative nanoscale mapping of three-phase thermal conductivities in filled skutterudites via scanning thermal microscopy

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National Science Review 2018年第1期5卷 59-69页

作者： Ehsan nasr Esfahani Feiyue Ma Shanyu Wang Yun Ou Jihui Yang Jiangyu Li Department of Mechanical Engineering University of Washington Shenzhen Key Laboratory of Nanobiomechanics Shenzhen Institutes of Advanced TechnologyChinese Academy of Sciences Department of Materials Science andEngineering University of Washington

In the last two decades, a nano structuring paradigm has been successfully applied in a wide range of thermoelectric materials, resulting in significant reduction in thermal conductivity and superior thermoelectric performance. These advances, however, have been accomplished without directly investigating the local thermoelectric properties, even though local electric current can be mapped with high spatial resolution. In fact, there still lacks an effective method that links the macroscopic thermoelectric performance to the local micro structures and properties. Here, we show that local thermal conductivity can be mapped quantitatively with good accuracy, nanometer resolution and one-to-one correspondence to the micro structure using a three-phase skutterudite as a model system. Scanning thermal microscopy combined with finite element simulations demonstrate close correlation between sample conductivity and probe resistance,enabling us to distinguish thermal conductivities spanning orders of magnitude, yet resolving thermal variation across a phase interface with small contrast. The technique thus provides a powerful tool to correlate local thermal conductivities, micro structures and macroscopic properties for nano structured materials in general and nano structured thermo electrics in particular.

关键词： thermal conductivity scanning thermal microscopy thermoelectric materials nanoscale heat transfer thermal imaging

Daley Issue in Time Planning of Construction Projects in Ministry of Public Works ＆ Road-Yemen

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Daley Issue in Time Planning of Construction Projects in Min...

作者： ABDULRAHMAN nasr GHALEB MOHAMMED 山东大学

学位级别：硕士

Poor project planning is considered a global and critical issue,it has been discussed and cited by many authors as a delay factor in the construction *** fact,project planning have several different aspects,in this research we only addresses the time aspect of project planning in construction project of（MPWH）Ministry of Public Works and Road in *** main aim of this research is particularly to examine ’poor project planning’concerning"time planning aspect"as a delay factor in construction projects carried out by the Ministry of Public Works and Road in Yemen and identify the reasons behind this issue by evaluating the procedures followed by Yemeni Ministry of Public Works and Road in conducting time planning for construction projects,investigating the reasons behind deficiencies in time planning,identifying the factors that may improve those deficiencies,and detecting factors that can impact（regardless of negative or positive consequences）project time *** order to achieve the research objective,a questionnaire was designed as the instrument of this *** questionnaire targeted a sample of 100 individuals of experts,project managers,project directors,project consultants engineer’s,projects supervisor,and administrative officers of Ministry of Public Works and Road,it was distributed among them in MPWH and all its branches in all Yemeni *** was employed as a statistical tool to analyze the respondents answer using the Frequency Index（FI）test in order to rank the respondents answer and Cronbach Alpha to measure the reliability and the internal consistency of the *** were required to answer different questions regarding their background,project time planning personnel,project time planning tools,and the relation between project time planning and project *** factors resulting in poor time planning of the construction projects of MPWH and the reasons behind were found through analysis of the data coll

关键词： Time Planning Project Delay Construction Projects Yemen

New insights into hydraulic fracturing fluids used for hightemperature wells

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Petroleum 2021年第1期7卷 70-79页

作者： Tariq Almubarak Leiming Li Jun Hong Ng Hisham nasr-El-Din Mohammed AlKhaldi Texas A&M University USA Aramco Services Company Saudi Arabia Saudi Aramco EXPEC ARC Saudi Arabia

Current interest in deep,low-permeability formations(<10 md)demands accelerated development of high-temperature hydraulic fracturing *** guar systems break down above 300°F and require higher polymer loadings to maintain thermal ***,higher polymer loadings generate more residue and damage to the proppant pack and the *** resolve these problems,a variety of high-temperature stabilizers are added to enhance the thermal stability of these fracturing fluids at temperatures above 300*** focus of this work is to:(1)identify those additives that best enhance temperature stability of fracturing fluids and(2)study the rheological influence of incorporating these additives on the fracturing fluid *** experimental fracturing-fluid solutions were prepared at a total polymer concentration of 30 and 40 lb/1000 *** such as synthetic polymer,oxygen scavengers,crosslinkers,crosslinker delay additives,and pH buffers were examined in this *** polymer solutions were crosslinked with a metallic crosslinker between 200 and 400°*** measurements were carried out in a highpressure/high-temperature(HP/HT)rheometer to evaluate rheology and thermal *** show that adding a synthetic polymer and a crosslinker with the slowest reaction rate improves the fracturing fluid thermal *** the three other additives tested,oxygen scavengers showed the greatest enhancement to thermal stability while pH buffers showed the *** the addition of high-temperature stabilizing additives,the fracturing fluid in this work was able to maintain a stable performance at temperatures up to 400°*** the thermal stability of fracturing fluids at a lower polymer loading remains a challenge in the *** work proposes techniques that can be used to enhance the thermal stability of fracturing *** knowledge about these different techniques will allow for better additive development and a

关键词： Oxygen scavenger Crosslinker Crosslinker delay Shear tolerance High temperature Synthetic polymer CMHPG Buffers

Anal cancer treatment:Current status and future perspectives

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World Journal of Gastroenterology 2015年第8期21卷 2294-2302页

作者： Marwan Ghosn Hampig Raphael Kourie Pamela Abdayem Joelle Antoun Dolly nasr Hematology-Oncology Department Faculty Of Medicine Saint Joseph University

Anal cancers(AC)are relatively rare *** incidence is increasing,particularly among men who have sex with other men due to widespread infection by human papilloma *** majority of anal cancers are squamous cell carcinomas,and they are treated according to *** local and locally advanced AC,concomitant chemoradiation therapy based on mitomycin C and 5-Fluorouracil(5-FU)is the current best treatment,while metastatic AC,chemotherapy with 5-FU and cisplatin remains the gold *** are no indications for induction or maintenance therapies in locally advanced *** novel strategies,such as targeted therapies,vaccination,immunotherapy and photodynamic therapy are in clinical trials for the treatment of AC,with promising results in some indications.

关键词： Anal cancer Optimum treatment Updates Guidelines N