检索结果-南通市图书馆

Noise Reduction Technique Applied to the Multichannel Analysis of Surface Waves

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2012年第5期86卷 1306-1311页

作者： Taohidul ISLAM Zamri CHIK Mohd Marzuki mustafa Department of Civil and Structural Engineering Faculty of Engineering and Built EnvironmentUniversiti Kebangsaan Malaysia43600 BangiMalaysia Department of Electrical and Electronics Engineering Patuakhali Science and Technology University8602 PatuakhaliBangladesh Department of Electrical and Electronics and System Engineering Faculty of Engineering and Built EnvironmentUniversiti Kebangsaan Malaysia43600 BangiMalaysia

This paper shows the presence of noises and technique to reduce these noises during the surface wave analysis. The frequency-dependent properties of Rayleigh-type surface waves can be used for imaging and characterizing the shallow subsurface. Interference by coherent source-generated noise inhibits the reliability of shear-wave velocities determined through inversion of the phase velocities of Rayleigh waves. Among these interferences by non-planar, non-fundamental mode Rayleigh waves （noise） are body waves, scattered and non-source-generated surface waves, and highermode surface waves. For the reduction of noise, the filtering technique is implemented in this paper for the multichannel analysis of surface wave method （MASW）. With the de-noising technique during the MASW method, more robust and reliable outcome is achieved. The significance of this paper is to obtain pre-awareness about noises during surface wave analysis and take better outcomes with denoising performance in near surface soil investigations.

关键词： multichannel analysis of surface wave method noises filtering near surface soil

Microstructure and hardness of Mg-based composites reinforced with Mg_2Si particles

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2009年第4期28卷 396-400页

作者： mustafa Aydin Cem zgür Osman San Mechanical Engineering Department Dumlupinar University Ceramic Engineering Department Dumlupinar University

Magnesium powders were mechanically alloyed with SiO2 powder particles having different particle sizes using nigh-energy ball milling techniques under Ar atmosphere for 1 h. The powders were consolidated with cold pressing under 560 MPa. They were then sintered at 550℃ for 45 min under Ar atmosphere. The composites obtained on the Mg-SiO2 system were investigated using the Archimedes principle, a differential scanning calorimeter, X-ray diffraction, optic microscopy, and scanning electron microscopy. For the mechanically alloyed powders, the solid-state reaction of the synthesis of Mg2Si and MgO progressed further during sintering of the materials. The results showed that the strengthening mechanisms were dependent on dispersion hardening of fine Mg2Si and MgO particulates dispersed homogeneously in the matrix. Mg-

关键词： based composites SiO2 mechanical alloying strengthening mechanism

Deep Learning-Based Robust DC Fault Protection Scheme for Meshed HVDC Grids

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2023年第6期9卷 2423-2434页

作者： Muhammad Zain Yousaf Hui Liu Ali Raza Ali mustafa the School of Electrical Engineering Guangxi UniversityNanning 530004China the School of Electrical Engineering University of LahoreLahore 39161Pakistan the School of Electrical Engineering Xi’an Jiaotong UniversityXi’an 710049China

Fast and reliable detection of faults is a significant technical challenge in transient-based protection for a modular multi-level converter(MMC)based high voltage direct current(HVDC)*** is because existing protection schemes rely heavily upon setting a complicated protective threshold,the failure of which causes high DC-fault currents in HVDC grids,and MMC is prone to such strong transient *** this context,this paper proposes a DC-line fault diagnosis technique based on a tuned long-short-term memory(LSTM)algorithm to improve the response and accuracy of transient-based *** discrete wavelet transform(DWT)extracts the transient features of DC-line voltages in the frequency-time *** healthy and faulty samples are incorporated during training even by considering the noise *** training,numerous test samples are run to evaluate the proposed algorithm’s robustness under various fault *** results show the proposed algorithm can detect DC faults and has a high recognition accuracy of 98.6%.Compared to contemporary techniques,it can perform well to identify DC-line faults because of the efficient training of characteristic features.

关键词： High voltage direct current(HVDC) longshort-term-memory(LSTM) primary protection voltage source converters(VSC)

Relation of coronary collateral circulation with epicardial fat volume in patients with stable coronary artery disease

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Geriatric Cardiology 2013年第4期10卷 344-348页

作者： Aslm Enhos Irfan Sahin Mehmet mustafa Can Ibrahim Biter mustafa Hakan Dinckal Victor Serebruany Bagc(i)lar Research and Education Hospital Cardiology Department Bagc(i)lar 34800 Istanbul Turkey

OBJECTIVE: To investigated the relationship between epicardial fat volume (EFV) and coronary collateral circulation (CCC) in patients with stable coronary artery disease (CAD)。 METHODS: The study population consisted of 152 consecutive patients with CAD who underwent coronary angiography and were found to have at least 95% significiant lesion in at least one major coronary artery。 EFV was assessed utilizing 64-multislice computed tomography。 The patients were classifield into impaired CCC group (Group 1, Rentrop grades0-1, n =58), or adequate CCC (Group 2, Rentrop grades 2-3, n = 94)。 RESULTS: The EFV values were significantly higher in paitients with adequate CCC than in those with impaired CCC。 In multivariate logistic regression analysis, EFV (OR = 1.059;95% CI: 1.035-1.085; P = 0.001); and presence of angina were independent predictors of adequate CCC。 In receiver-operating characteristic curve analysis, the EFV value > 106.5 mL yielded an area under the curve value of 0.84, with the test sensitivity of 49.3%, and with 98.3% specifity。 CONCLUSIONS: High EFV, and the presence of angina independently predict adequate CCC in patients with stable coronary artery disease。 This association offers new diagnostic opportinities to assess collateral flow by conventional ultrasound techniques。

关键词： Angına Collateral circulation Coronary artery disease Epicardial adipose tissue

Optimization of drill bit replacement time in open-cast coal mines

在线全文

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2019年第3期6卷 399-407页

作者： Omer Faruk Ugurlu mustafa Kumral Department of Mining and Materials Engineering McGill University 3450 University Street Montreal QC H3A 0E8 Canada

To gain a competitive edge within the international and compet让ive setting of coal markets, coal producers must find new ways of reducing costs. Increasing bench drilling efficiency and performance in open-cast coal mines has the potential to generate savings. Specifically, monitoring, analyzing, and optimizing the drilling operation can reduce drilling costs. For example, determining the optimal drill bit replacement time will help to achieve the desirable penetration rate. This paper presents a life data analysis of drill bits to fit a statistical distribution using failure records. These results are then used to formulate a cost minimization problem to estimate the drill bit replacement time using the evolutionary algorithm. The effect of cost on the uncertainty associated with replacement time is assessed through Monte-Carlo simulation. The relationship between the total expected replacement cost and replacement time is also presented. A case study shows that the proposed approach can be used to assist with designing a drill bit replacement schedule and minimize costs in open-cast coal mines.

关键词： Cost minimization Drilling operation Optimum replacement time Evolutionary algorithm Sensitivity analysis Monte Carlo simulation

Event-Triggered Sliding Mode Control for Trajectory Tracking of Nonlinear Systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2020年第1期7卷 307-314页

作者： Aquib mustafa Narendra K.Dhar Nishchal K Verma Department of Electrical Engineering Indian Institute of Technology KanpurUP 208016India

In this paper, an event-triggered sliding mode control approach for trajectory tracking problem of nonlinear input affine system with disturbance has been proposed. A second order robotic manipulator system has been modeled into a general nonlinear input affine system. Initially, the global asymptotic stability is ensured with conventional periodic sampling approach for reference trajectory tracking. Then the proposed approach of event-triggered sliding mode control is discussed which guarantees semi-global uniform ultimate boundedness. The proposed control approach guarantees non-accumulation of control updates ensuring lower bounds on inter-event triggering instants avoiding Zeno behavior in presence of the disturbance. The system shows better performance in terms of reduced control updates, ensures system stability which further guarantees optimization of resource usage and cost. The simulation results are provided for validation of proposed methodology for tracking problem by a robotic manipulator. The number of aperiodic control updates is found to be approximately 44% and 61% in the presence of constant and time-varying disturbances respectively.

关键词： Event-trigger inter execution time stability sliding mode control trajectory tracking

Data-Driven Load Forecasting Using Machine Learning and Meteorological Data

在线全文

学校读者我要写书评

暂无评论

Computer Systems Science & Engineering 2023年第3期44卷 1973-1988页

作者： Aishah Alrashidi Ali mustafa Qamar Department of Computer Science College of ComputerQassim UniversityBuraydahSaudi Arabia

Electrical load forecasting is very crucial for electrical power systems’planning and *** electrical buildings’load demand and meteorological datasets may contain hidden patterns that are required to be investigated and studied to show their potential impact on load *** meteorological data are analyzed in this study through different data mining techniques aiming to predict the electrical load demand of a factory located in Riyadh,Saudi *** factory load and meteorological data used in this study are recorded hourly between 2016 and *** data are provided by King Abdullah City for Atomic and Renewable Energy and Saudi Electricity Company at a site located in *** applying the data pre-processing techniques to prepare the data,different machine learning algorithms,namely Artificial Neural Network and Support Vector Regression(SVR),are applied and compared to predict the factory *** addition,for the sake of selecting the optimal set of features,13 different combinations of features are investigated in this *** outcomes of this study emphasize selecting the optimal set of features as more features may add complexity to the learning ***,the SVR algorithm with six features provides the most accurate prediction values to predict the factory load.

关键词： Electricity load forecasting meteorological data machine learning feature selection modeling real-world problems predictive analytics

The Allelopathic Effects of Sunflower and Wheat Root Exudates on Sinapis arvensis and Sinapis alba

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Phyton-International Journal of Experimental Botany 2019年第4期88卷 413-423页

作者： Bengu Turkyilmaz Unal mustafa Bayram NigdeÖmer Halisdemir University Faculty of Arts and SciencesDepartment of Biotechnology51240NigdeTurkey NigdeÖmer Halisdemir University Faculty of Arts and SciencesDepartment of Biology51240NigdeTurkey

In this study,we aimed to investigate the allelopathic effects of sunflower and wheat root exudates on the common weeds such as wild mustard and white mustard in our *** root exudates which were obtained by soaking 8 weeks old sunflower and wheat seedlings(20 or 40 seedlings)in 100 mL of distilled water for 3 days were applied to the leaves of wild mustard and white *** order to compare the allelopathic effect,the recommended dose(1 ***^(-1))and twice the recommended dose(2 ***^(-1))of Gromstor(Tribenuron-methyl),a herbicide preferred by farmers for the chemical control of these weeds was also *** allelopathy was performed for wild mustard and white mustard seedlings by the measurement of different physiological and biochemical parameters,such as chlorophyll a,chlorophyll b,total chlorophyll,carotenoid,proline,total protein amounts and superoxide dismutase enzyme *** amounts of total chl and carotenoid in wild mustard leaves decreased in all treatment groups compared to *** highest decrease in total chl(50.93%)and carotenoid(46.69%)was oberved in the treatment of 40 wheat seedlings.100 mL^(-1) distilled *** the white mustard leaves,the amount of total chl in all treatment groups except the treatment group of Gromstor 2 ***^(-1) and carotenoid in all treatment groups increased compared to the *** highest increases again were observed in 40 wheat seedlings.100 mL^(-1) distilled water *** proline amounts in wild mustard and white mustard increased in all treatment *** highest increase was observed for the treatment of 20 wheat seedlings.100 mL^(-1) distilled water in wild mustard(459.69%)and 40 sunflower seedlings.100 mL^(-1) distilled water in white mustard plant(104.70%).In superoxide dismutase enzyme activities,treatments decreased activity except treatment of 40 sunflower seedling root exudate in wild mustard,while increased activity outside commercial herbicide treatment in white *** r

关键词： Allelopathy antioxidant enzymes bioherbicide photosynthetic pigments white mustard wild mustard

Constraints on unconsolidated pyroclastic flow sediments related REE enrichments originated from potassic-alkaline Gölcük stratovolcano: Darıdere-Direkli-Yakaören (DDY) table 4deposits, southwestern Anatolia of Turkey

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geochimica 2021年第6期40卷 926-944页

作者： Murat Budakoglu Ali Tugcan unluer Zeynep Doner Huseyin Kocaturk mustafa Kaya mustafa Kumral M.Sezai Kirikoglu Department of Geological Engineering Faculty of MinesIstanbul Technical UniversityIstanbulTurkey

In the last five decades,Rare Earth Elements(REE)are mostly produced from carbonatite complexes and alkaline magmatic *** this respect,pyroclastic flows produced by the potassic-alkaline Gölcük volcanism in the Isparta(SW,Turkey)angle stand out as an important target area where REE enrichments can be *** study focuses on the REE potential,geochemical and mineralogical characteristics of REE-bearing minerals as well as formation modeling of unconsolidated pyroclastic flows in Darıdere-Direkli-Yakaören(DDY)deposits in ***-bearing minerals of DDY deposits which contain abundant trachytic-trachyandesitic rock fragments were determined as fluorapatite,britholite,and chevkinite by using XRD and SEM–EDX *** to the geochemical analysis,the vast majority of RREE(up to 996 ppm)content is LREE such as La,Ce and ***ıdere is the most REE enriched region followed by Yakaören and Direkli regions in terms of LREE(574.9 ppm),relative to MREE(38.5 ppm)and HREE(5.28 ppm)*** results are also on par with subduction-related Italian extrusive carbonatites such as Polino,Cupaello and San *** DDY deposits can also be comparable with intraplate extrusive REE deposits in terms of LREE enrichments,however,HREE,Nb,Th and Zr values are generally *** RREE concentrations tend to rise with the increasing contents of alkaline elements(Na and K),HFSE(such as Nb and U),as well as LILE(Ba,Sr and Rb)and are negatively affected by sedimentary carbonate *** economic value of the DDY deposits can gain importance due to the increasing global demand for LREE’s.

关键词： Pyroclastic flows Rare Earth Elements(REE) Apatite Britholite Chevkinite Alkaline-Ultrapotasic magmatism