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Ureteroscopy with Holmium: YAG Laser—A Initial Study in the Urology Department of the Pr Bocar Sidy Sall University Hospital of Kati

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Open Journal of Urology 2024年第4期14卷 207-216页

作者： Amadou Kassogue Idrissa Sissoko Daouda Sangare Moussa Salifou Diallo hamed Sylla Mahamadou Traore Boureima Coulibaly Salia Coulibaly Modibo Diakite Modibo Togola Fadima Tall Ilias Guindo Ben Naoum Kamel Mamadou Lamine Diakite Urology Department University Hospital of Pr Bocar Sidy Sall Kati Mali Radiology Department University Hospital of Pr Bocar Sidy Sall Kati Mali Anesthesy and Reanimation Department University Hospital of Pr Bocar Sidy Sall Kati Mali Urology Department University Hospital Nimes France Urology Department University Hospital of Point G Bamako Mali

Introduction: Ureteroscopy is a minimally invasive endoscopic surgery which provides access to the ureter, pyelon and calyceal cavities via the urethra and the bladder. Laser ureteroscopy uses the laser as an energy source to treat the stone and eliminate it naturally. Minimally invasive endoscopic methods are struggling to become popular in sub-Saharan African countries, especially for the upper urinary tract. The objective of our work was to report the results of our first laser ureteroscopy experience in the department. Materials and Methods: This was a prospective and descriptive study running from December 1, 2023 to February 19, 2024. Included in our study was any case of upper urinary tract stone operated by Laser ureteroscopy. The characteristics of the lithiasis were determined by CT scan. Sterilization of urine was verified by carrying out a cytobacteriological examination of urine. Ureteral lithiasis was approached by semi-rigid ureteroscopy. Renal lithiasis was immediately addressed by flexible ureteroscopy. Ureteroscopy was coupled with a Holmium YAG laser. A double J ureteral catheter was placed after the operation. A 230 µm laser fiber was used in each case with a generator with a power of 35 watts (Storz Calculase III type). An access sheath was used in all cases of flexible ureteroscopy. The parameters studied were: sociodemographic characteristics, lithiasis (site, size, number, density, topography), type of anesthesia, duration of laser use, duration of intervention, postoperative outcomes. Data entry and analysis were carried out using the software (Word 2016 and SPSS). Result: We collected 30 cases of laser ureteroscopy. The average age was 37 years with extremes of 9 and 79 years. The male gender was more represented. The most common age group was 24-39 years old. Renal colic was the most frequent reason for admission, 12 patients (40%). On physical examination, lumbar tenderness was present in 47% (14 patients). ECBU was positive in 4 patients

关键词： Ureteroscopy Semi-Rigid Flexible Holmium YAG Laser

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Influence of rotational speed in friction surfacing of nickel-aluminide reinforced aluminum matrix composite on commercially pure aluminum

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Transactions of Nonferrous Metals Society of China 2022年第8期32卷 2480-2493页

作者： Mobina YOUSEFI hamed JAMSHIDI AVAL Department of Materials Engineering Babol Noshirvani University of TechnologyShariati AvenueBabol 47148-71167Iran

The effect of rotational speed in the friction surfacing of nickel-aluminide reinforced Al-Zn-Mg-Cu alloy matrix composite on commercially pure aluminum was investigated. The nickel-aluminide reinforcement was fabricated by in-situ methods based on adding nickel powders to Al-Zn-Mg-Cu alloy melt during the semi-solid casting *** findings showed that an increase in the rotational speed from 600 to 1000 r/min raised the coating efficiency from 65% to 76%. Besides, there was no significant difference between coating efficiencies in the coating with and without nickel-aluminide. The outcomes showed that if the coating was applied at a rotational speed of 1000 r/min, a traverse speed of 100 mm/min, and an axial feeding rate of 125 mm/min, the hardness and shear strength of the substrate increased by up to 225% and 195%, respectively. But the wear rate of the substrate dropped by 75%. Although the hardness of the coating containing nickel-aluminide increases by up to 32% compared to the coating without nickel-aluminide, nickel-aluminide does not affect the thermal stability of the coating.

关键词： nickel-aluminide aluminum matrix composite friction surfacing wear resistance

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Power maximization of variable-speed variable-pitch wind turbines using passive adaptive neural fault tolerant control

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Frontiers of Mechanical Engineering 2017年第3期12卷 377-388页

作者： hamed HABIBI hamed RAHIMI NOHOOJI Ian HOWARD Faculty of Science and Engineering School of Civil and MechanicalEngineering Curtin University Perth Australia

Power maximization has always been a practical consideration in wind turbines. The question of how to address optimal power capture, especially when the system dynamics are nonlinear and the actuators are subject to unknown faults, is significant. This paper studies the control methodology for variable-speed variable-pitch wind turbines including the effects of uncertain nonlinear dynamics, system fault uncertainties, and unknown external disturbances. The nonlinear model of the wind turbine is presented, and the problem of maximizing extracted energy is formulated by designing the optimal desired states. With the known system, a model-based nonlinear controller is designed; then, to handle uncertainties, the unknown nonlinearities of the wind turbine are estimated by utilizing radial basis function neural networks. The adaptive neural fault tolerant control is designed passively to be robust on model uncertainties, disturbances including wind speed and model noises, and completely unknown actuator faults including generator torque and pitch actuator torque. The Lyapunov direct method is employed to prove that the closed-loop system is uniformly bounded. Simulation studies are performed to verify the effectiveness of the proposed method.

关键词： wind turbine nonlinear model maximum power tracking passive fault tolerant control adaptive neural control

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Dilation angle variations in plastic zone around tunnels in rocks-constant or variable dilation parameter

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Journal of Central South University 2018年第10期25卷 2550-2566页

作者： hamed MOLLADAVOODI Marzieh RAHMATI Department of Mining and Metallurgy Amirkabir University of Technology

Dilation angle is a significant parameter needed for numerical simulation of *** though dilation parameter is physically variable and dependent on confinement and experienced shear plastic strain based on the existing dilation models,numerical simulations of tunnels and underground openings with constant dilation parameter usually lead to satisfactory results in practical *** study aims to find out why constant dilation angle is enough under practical conditions to simulate numerically tunnels and underground excavations in spite of the fact that dilation angle is variable in laboratory and experimental *** this aim,this work studies how mobilized dilation angle varies in a plastic zone surrounding a *** the circular tunnel under uniform in situ stress field,the stepwise finite difference approximation analytical solution considering strain softening rock mass behavior with mobilized dilation angle was used to study how mobilized dilation angle varies in plastic zone around tunnel under very different *** practical conditions determined in this study,dilative behavior of all over the plastic zone around the tunnel can be approximated to constant dilation angle in the middle region of the plastic ***,the plastic zone displacements for mobilized and constant dilation angle models are compared with each *** investigation under more general non-uniform in situ stress conditions and non-circular tunnels is performed by using the commercial finite difference software to numerically simulate the Mine-by experimental tunnel of AECL(Atomic Energy of Canada Limited)and the arched *** the Mine-by and arched tunnels were numerically simulated based on the mobilized dilation angle model,the variability associated with dilation angle around the simulated Mine-by and arched tunnels is insignificant,and dilation angle is approximately constant in the plastic zone.

关键词： dilation post-peak behavior plastic zone strain softening

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Fast uniform content-based satellite image registration using the scale-invariant feature transform descriptor

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Frontiers of Information Technology & Electronic Engineering 2017年第8期18卷 1108-1116页

作者： hamed BOZORGI Ali JAFARI Electrical Engineering Department University of Guilan Rasht 41635-3756 Iran School of Electrical & Electronic Engineering Malek Ashtar University of Technology Tehran 15875-1774 Iran

Content-based satellite image registration is a difficult issue in the fields of remote sensing and image processing. The difficulty is more significant in the case of matching multisource remote sensing images which suffer from illumination, rotation, and source differences. The scale-invariant feature transform （SIFT） algorithm has been used successfully in satellite image registration problems. Also, many researchers have applied a local SIFT descriptor to improve the image retrieval process. Despite its robustness, this algorithm has some difficulties with the quality and quantity of the extracted local feature points in multisource remote sensing. Furthermore, high dimensionality of the local features extracted by SIFT results in time-consuming computational processes alongside high storage requirements for saving the relevant information, which are important factors in content-based image retrieval （CBIR） applications. In this paper, a novel method is introduced to transform the local SIFT features to global features for multisource remote sensing. The quality and quantity of SIFT local features have been enhanced by applying contrast equalization on images in a pre-processing stage. Considering the local features of each image in the reference database as a separate class, linear discriminant analysis （LDA） is used to transform the local features to global features while reducing di- mensionality of the feature space. This will also significantly reduce the computational time and storage required. Applying the trained kernel on verification data and mapping them showed a successful retrieval rate of 91.67% for test feature points.

关键词： Content-based image retrieval Feature point distribution Image registration Linear discriminant analysis Remotesensing Scale-invariant feature transform

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A method for improving graph queries processing using positional inverted index (P.I.I) idea in search engines and parallelization techniques

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Journal of Central South University 2016年第1期23卷 150-159页

作者： hamed Dinari Hassan Naderi Web and Search Engines Laboratory School of Computer EngineeringIran University of Science and Technology

The idea of positional inverted index is exploited for indexing of graph database. The main idea is the use of hashing tables in order to prune a considerable portion of graph database that cannot contain the answer set. These tables are implemented using column-based techniques and are used to store graphs of database, frequent sub-graphs and the neighborhood of nodes. In order to exact checking of remaining graphs, the vertex invariant is used for isomorphism test which can be parallel implemented. The results of evaluation indicate that proposed method outperforms existing methods.

关键词： graph query processing frequent subgraph graph mining data mining positional inverted index

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Uplift of Symmetrical Anchor Plates by Using Grid-Fixed Reinforced Reinforcement in Cohesionless Soil

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China Ocean Engineering 2014年第1期28卷 115-126页

作者： hamed Niroumand Khairul Anuar Kassim Department of Geotechnical Engineering Faculty of Civil EngineeringUniversity of Technology Malaysia

Uplift response of symmetrical anchor plates with and without grid fixed reinforced （GFR） reinforcement was evaluated in model tests and numerical simulations by Plaxis. Many variations of reinforcement layers were used to reinforce the sandy soil over symmetrical anchor plates. In the current research, different factors such as relative density of sand, embedment ratios, and various GFR parameters including size, number of layers, and the proximity of the layer to the symmetrical anchor plate were investigated in a scale model. The failure mechanism and the associated rupture surface were observed and evaluated. GFR, a tied up system made of fiber reinforcement polymer （FRP） strips and end balls, was connected to the geosynthetic material and anchored into the soil. Test results showed that using GFR reinforcement significantly improved the uplift capacity of anchor plates. It was found that the inclusion of one layer of GFR, which rested directly on the top of the anchor plate, was more effective in enhancing the anchor capacity itself than other methods. It was found that by including GFR the uplift response was improved by 29%. Multi layers of GFR proved more effective in enhancing the uplift capacity than a single GFR reinforcement. This is due to the additional anchorage provided by the GFR at each level of reinforcement. In general, the results show that the uplift capacity of symmetrical anchor plates in loose and dense sand can be significantly increased by the inclusion of GFR. It was also observed that the inclusion of GFR reduced the requirement for a large L/D ratio to achieve the required uplift capacity. The laboratory and numerical analysis results are found to be in agreement in terms of breakout factor and failure mechanism pattern.

关键词： grid fixed reinforced (GFR) Plaxis fiber reinforcement polymer (FRP) uplift response anchor plate

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Microstructural characterization and mechanical properties of friction surfaced AA2024-Ag composites

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Transactions of Nonferrous Metals Society of China 2020年第7期30卷 1756-1770页

作者： Parisa PIRHAYATI hamed JAMSHIDI AVAL Department of Materials Engineering Babol Noshirvani University of TechnologyShariati AvenueBabol 47148-71167Iran

The effects of Ag on the microstructure, mechanical properties, and electrical conductivity of AA2024 aluminum alloy coating were investigated. It was fabricated by friction surfacing as an additive manufacturing process. To carry out this investigation, Ag was added by 5.3, 10.6, and 16.0 wt.% to an AA2024 consumable rod by inserting holes in it. It was found that due to the strengthening by solid solution and the formation of precipitates and intermetallic containing Ag, the driving force for grain growth is reduced and consequently the grain size of the coating is decreased. After artificial aging heat treatment, the electrical conductivities of the coatings containing 0 and 16.0 wt.% Ag are increased by 4.15%(IACS) and decreased by 2.15%(IACS), respectively. While considering a linear relationship, it can be proposed that for a 1 wt.% Ag increase, the strength and hardness of the coating will be increased by 1.8% and 1.0%, respectively. It was established that the effect of Al6(Cu,Ag)Mg4 precipitate formation on strengthening is greater than that of Ag-rich intermetallic.

关键词： friction surfacing AA2024 aluminum alloy Ag powder AA2024-Ag composite

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Mass transfer investigation and operational sensitivity analysis of aminebased industrial CO_2 capture plant

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Chinese Journal of Chemical Engineering 2019年第3期27卷 534-543页

作者： Abbas Hemmati hamed Rashidi Chemical Engineering Department Faculty of Energy Kermanshah University of Technology

In this article, the industrial process of CO_2 capture using monoethanolamine as an aqueous solvent was probed carefully from the mass transfer viewpoint. The simulation of this process was done using Rate-Base model, based on two-film theory. The results were validated against real plant data. Compared to the operational unit, the error of calculating absorption percentage and CO_2 loading was estimated around 2%. The liquid temperature profiles calculated by the model agree well with the real temperature along the absorption tower, emphasizing the accuracy of this model. Operational sensitivity analysis of absorption tower was also done with the aim of determining sensitive parameters for the optimized design of absorption tower and optimized operational conditions. Hence,the sensitivity analysis was done for the flow rate of gas, the flow rate of solvent, flue gas temperature, inlet solvent temperature, CO_2 concentration in the flue gas, loading of inlet solvent, and MEA concentration in the solvent. CO_2 absorption percentage, the profile of loading, liquid temperature profile and finally profile of CO_2 mole fraction in gas phase along the absorption tower were studied. To elaborate mass transfer phenomena, enhancement factor, interfacial area, molar flux and liquid hold up were probed. The results show that regarding the CO_2 absorption, the most important parameter was the gas flow rate. Comparing liquid temperature profiles showed that the most important parameter affecting the temperature of the rich solvent was MEA concentration.

关键词： Carbon dioxide Monoethanolamine Rate-base model Enhancement factor Sensitivity analysis

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An efficient two-stage approach for structural damage detection using meta-heuristic algorithms and group method of data handling surrogate model

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Frontiers of Structural and Civil Engineering 2020年第4期14卷 907-929页

作者： hamed FATHNEJAT Behrouz AHMADI-NEDUSHAN Department of Civil Engineering Yazd UniversityYazd 89195-741Iran

In this study,the performance of an efficient two-stage methodology which is applied in a damage detection system using a surrogate model of the structure has been *** the first stage,in order to locate the damage accurately,the performance of the modal strain energy based index for using different numbers of natural mode shapes has been evaluated using the confusion *** the second stage,to estimate the damage extent,the sensitivity of most used modal properties due to damage,such as natural frequency and flexibility matrix is compared with the mean normalized modal strain energy(MNMSE)of suspected damaged ***,a modal property change vector is evaluated using the group method of data handling(GMDH)network as a surrogate model during damage extent estimation by optimization algorithm;in this part of methodology,the performance of the three popular optimization algorithms including particle swarm optimization(PSO),bat algorithm(BA),and colliding bodies optimization(CBO)is examined and in this regard,root mean square deviation(RMSD)based on the modal property change vector has been proposed as an objective ***,the effect of noise in the measurement of structural responses by the sensors has also been ***,in order to achieve the most generalized neural network as a surrogate model,GMDH performance is compared with a properly trained cascade feed-forward neural network(CFNN)with log-sigmoid hidden layer transfer *** results indicate that the accuracy of damage extent estimation is acceptable in the case of integration of PSO and ***,the GMDH model is also more efficient and mimics the behavior of the structure slightly better than CFNN model.

关键词： two-stage method modal strain energy surrogate model GMDH optimization damage detection

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