457 research outputs found
Speed Sensorless Control of Six-Phase Asynchronous Motor Drive
Multi -phase ac motor drives are nowadays considered for various applications, due to many advantages that they offer when compared to three-phase motors. Cancellation of mechanical position or speed sensors at the motor shaft have the attractions for adjustable speed drives of induction motor to reduce the cost and increase the reliability. To replace the sensor, information of the rotor speed is extracted from measured stator currents and voltages at motor terminals. This paper investigates speed estimation method using model reference adaptive system (MRAS) to improve the performance of a sensorless vector controller of six-phase induction motor (IM). In the proposed method, the stator current is used as the state variable to estimate the speed. Since the stator current error is represented as a function of the first degree for the error value in the speed estimation, the proposed method provides fast speed estimation and is also, more robust to variations in the stator resistance, compared with other MRAS methods. Consequently, this method can improve the performance of a sensorless vector controller in a low speed region and at zero-speed. The proposed method is verified by simulation using the Matlab/Simulink package. The performance of the proposed system is investigated at different operating conditions. The proposed controller is robust and suitable for high performance six-phase induction motor drives. Simulation results validate the proposed approaches
Ahmed’as Ibn Fadlan’as ir Bayard’as Taylor’as – kelionių literatūros kūrėjai ar vertėjai?
In this article, two works of travel writing, Resala (922) by Ahmed Ibn Fadlan and Travels in Arabia (1889) by Bayard Taylor, are explored to show how the genre as a whole serves as one way of translating culture in order to better understand and discover it. It examines how ideology affects cultural translation in travel writing and how this leads to othering. We begin with close readings of the texts for major content themes, including religion, sex, traditions, etc. These are analyzed for instantiations of inaccurate cultural translation, ideology, and othering. The use of pronouns, nouns, and adjectives is looked at to explore their othering effect. The results show that inaccurate cultural translations are sometimes influenced by ideology and usually lead to othering. The analyzed samples of travel writing rather reveal the predominant mindsets and leanings of their authors and cultures of their origin than those they attempt to introduce to their readers.Straipsnyje, pasitelkiant du kelionių literatūros tekstus – Ahmed’o Ibn Fadlan’o knygą apie jo kelionę su misija į Rusiją Resala (922) bei Bayard’o Taylor’o kelionių po arabų šalis užrašus Travels in Arabia (1889), – gilinamasi į tai, kaip kelionių literatūros žanras funkcionuoja kaip tam tikras kultūros vertimas siekiant tą kultūrą geriau suprasti ir pristatyti skaitytojams. Keliamas tikslas išsiaiškinti, kaip kultūrinį vertimą kelionių literatūroje veikia ideologija ir kaip dėl šio poveikio pristatomoji kultūra sukitinama. Pirma tekstai atidžiai skaitomi siekiant išskirti pagrindines atsikartojančias temas: religiją, seksą, tradicijas ir kitas. Analizuojant šių temų raišką, išrenkami netikslaus kultūrinio vertimo, ideologijos raiškos ir sukitinimo pavyzdžiai. Tiriama, kokį sukitinamąjį poveikį turi įvardžių, daiktavardžių ir būdvardžių vartosena. Tyrimas rodo, kad abiejuose tekstuose klaidingą kultūrinį vertimą kai kuriais atvejais lemia autorių ideologija – toks vertimas įtvirtina pristatomos kultūros kaip „Kito“ kultūros įvaizdį. Šie analizuojami kelionių literatūros pavyzdžiai labiau atskleidžia pačių autorių bei jų kilmės kultūrų, o ne skaitytojams pristatomų kultūrų nuostatas ir pažiūras
Fuzzy-rough set and fuzzy ID3 decision approaches to knowledge discovery in datasets
Fuzzy rough sets are the generalization of traditional rough sets to deal with both fuzziness and vagueness in data. The existing researches on fuzzy rough sets mainly concentrate on the construction of approximation operators. Less effort has been put on the knowledge discovery in datasets with fuzzy rough sets. This paper mainly focuses on knowledge discovery in datasets with fuzzy rough sets. After analyzing the previous works on knowledge discovery with fuzzy rough sets, we introduce formal concepts of attribute reduction with fuzzy rough sets and completely study the structure of attribute reduction
Bioactive Lactoferrin-Derived Peptides
Lactoferrin (LF) is a member of the transferrin family that is a cationic iron-binding protein. It is an 80-kDa glycoprotein that is found in many secretions in the body and is highly present in milk and colostrums. It exerts antibacterial effects and has a wide range of biological activities. Moreover, it is considered as a precursor of different peptides that have multifunctional bioactivities. During the last decade, several applications of LF and its peptides have been discovered, which has led to its commercial production. Therefore, LF and its peptides can offer a variety of specialized ingredients that can be tailored to meet the needs of natural food preservatives and functional food ingredients
Role of multi-detector computed tomography in the evaluation of pancreatic tumors
AbstractObjectiveThe purpose of this study was to determine the role of multidetector computed tomography (MDCT) in evaluation and prediction of pancreatic tumors resectability.Patients and methodsThe study included 20 patients who had pancreatic masses, 16 males and 4 females, and their age range was 30–70years with a mean age of 58.0years. All the patients underwent non-contrast and contrast enhanced Multi-slice CT using a 16-slice machine. The gold standard for diagnosis was histopathology and operative data.ResultsAdenocarcinoma as reported by pathological studies was found in 8 patients, cyst adenocarcinoma in one patient, infiltrative adenocarcinoma in 2 patients, intraductal papillary mucinous tumor in 2 patients, mucinous cyst adenocarcinoma in one patient, pancreatic pseudo cyst in 2 patients and mucinous cystadenoma in 4 patients. According to MDCT criteria 6 patients were considered suitable for tumor resection and 14 patients were considered inoperable with unresectable tumor, one out of the 6 operable patients was unresectable during operation due to the invasion of the superior mesenteric vein with infiltration of the mesenteric root.ConclusionContrast-enhanced multiphase pancreatic imaging by multislice computerized tomography (MSCT) with its postprocessing techniques represents the image of choice for diagnosis and predicting pancreatic masses and resectability
Utilizing of virtual simulation to fitting the industrial pattern, Prototyping section, in Garment Factories “Case Study”
3D technology is considered one of the Pattern digital technologies that help this technology to increase, ease and speed of completion of industrial processes. This study deals with how to take advantage of 3D technology in developing the performance of the samples department in the technical department of ready-to-wear factories, in order to solve the problems of the samples section associated with the implementation of the 2D Pattern, as this problem was concluded through field study and practical experiences in ready-to-wear factories in Egypt.Controlling the fitting Pattern of clothes in the samples section faces many difficulties, the most important of which is the incompatibility of the industrial Pattern drawn with the human body “Pattern ". Where defects appeared in the product after conducting and implementing the first sample, which required making adjustments to the industrial Pattern and re-executing the sample a second time until it became free from defects and ready to perform the grading according to the measurements and the "order" of the operation order required to be executed to start production processes, which results in it. In the presence of lost time to implement the sample, as well as wasted effort, and wastes in the raw materials used in the implementation of the sample (fabric/ accessories / threads / and direct and indirect costs) that will be quantified after that.In order to find a solution to this problem, this research presents a case study using the "CLO5.1" program to improve the industrial Pattern in order to improve the quality of the male industrial Pattern drawing using 3D technology by making adjustments to some areas where the stress and stress ratios are high due to the lack of nan fitting of the Pattern. Industrial, which does not appear clearly even during implementation. The study concluded that the implementation of the CLO5.1 program in the sample section has succeeded in reducing the time wastage for sample production and the wastage of raw materials, thus reducing the cost of sample productionKey words :( 3Dtechnology ، pattern، Prototyping ، Garment Factories ،virtual simulation
Color Doppler US and tri-phasic CT in differentiating benign from malignant portal vein thrombosis (PVT)
AbstractObjective: To evaluate the efficacy of color Doppler US and tri-phasic CT in discriminating benign from malignant PVT. Patients and methods: This study included 30 patients presented ultrasonically with PVT and referred for color Doppler US and Tri-phasic CT examination for discriminating the benign from malignant PVT. The color Doppler US and tri-phasic CT results were compared and correlated with available histopathological results in the patients who had FNAC. Results: Those 30 patients were classified according to US, Tri-phasic CT, lab., findings into two groups: G.(A) included 16 patients with malignant PVT and G.(B) included 14 patients with benign PVT. Intrathrombus pulsatile flow was depicted in 12 patients with malignant PVT (12/16) (75%), while non-depicted in 14 patients with benign PVT with 100% specificity. On tri-phasic CT, neovascularity and an early arterial enhancement of PVT were depicted in 14 cases with malignant PVT with 87.5% sensitivity and non-depicted in 14 benign cases with PVT with 100% specificity. Conclusion: Distinguishing benign from malignant PVT in patients with HCC is required to determine the management plan. The color Doppler study of PVT should be an essential step in evaluation of patients with HCC. The combination of Color Doppler US and tri-phasic CT is common and essential for more accurate evaluation and differentiation of benign from malignant PVT
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