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991.
992.
Forty-five patients with oral or pharyngeal swellings were subjected to fine needle aspiration cytology (FNAC) of the mucosal surface over eight years. The age of the patients ranged from 2 to 85 years. The male:female ratio was 25:20. The common sites of involvement were palate (16 cases), cheek (9), pharynx (7) and tonsillar/peritonsillar area (6). Tongue, maxilla, alveolus and lips were less frequently involved. FNAC played an important role in differentiating inflammatory from neoplastic lesions and also benign from malignant neoplasms. Fifteen cases were cytologically diagnosed as benign neoplasms and included pleomorphic adenoma (11 cases), schwannoma (2), odontogenic tumor (1) and benign neoplasm not otherwise specified (1). Sixteen cases were diagnosed as malignancies. There were seven cases of malignant salivary gland tumors and 6 of squamous cell carcinoma. Two cases were high grade non-Hodgkin's lymphomas, and one was malignant odontogenic tumor. Of the 11 inflammatory or reactive lesions, 4 were found to be harboring Actinomyces. The rate of inadequate sampling was 6.7%. Histopathology reports on excised tissue were available for 10 cases only. Seven of nine cases with adequate cytology (77.88%) showed complete agreement with histology.  相似文献   
993.
994.
Cocaine abuse today has reached greater heights than it did during the first cocaine epidemic in the late nineteenth century. It is estimated that one out of every four Americans has used cocaine and some six million people in the US use it regularly. Although cocaine affects all systems in the body, the central nervous system (CNS) is the primary target. Cocaine blocks the reuptake of neurotransmitters in the neuronal synapses. Almost all CNS effects of cocaine can be attributed to this mechanism. Euphoria, pharmacological pleasure and intense cocaine craving share basis in this system. The effects of cocaine on other organ systems, in addition to its effects on the CNS, account for the majority of the complications associated with cocaine abuse. In this paper, the CNS effects following cocaine administration and their treatment are discussed.  相似文献   
995.
Fatigue lives at high peak stresses for peak-aged (T6) and overaged (T73) 7075 aluminum alloy were compared in the uncorroded and precorroded (pitted) states. Absolute fatigue lives of T73 samples were much higher than that of T6 in the virgin as well as precorroded condition, but the normalized life of T73 was less than that of T6, indicating an intrinsic crack initiation resistance in the former, borne out by fractography, which showed that fatigue cracks almost always initiated at pits for T73 but not for T6. The various crack initiation methodologies observed and the effect of pitting on fatigue lives in the two aging conditions are discussed.  相似文献   
996.
The present work investigates the effect of cold deformation on the evolution of microstructure and textures during recrystallization in 0.08%C steel. The cold rolling texture consists of partial α-fiber (RD//〈110〉) and complete γ-fiber (ND//〈111〉) along with Goss ({110}〈001〉) and cube ({100}〈100〉}) texture components. The sharpness of α-fiber, γ-fiber and cube component increases with the increase in rolling reduction from 70 to 85% while that of Goss component decreases. After recrystallization (750 and 800°C), the textures were composed of α and γ-fiber along with significant Goss components. The strength of γ-fiber decreases after annealing. The presence of Goss component in recrystallization textures is attributed to preferential nucleation in {111}〈112〉 type deformed grains.  相似文献   
997.
Numerical models of a cathode block assembly in a Hall–Hèroult cell, comprising of liquid aluminium, carbon block, current collector, ramming paste and a copper insert were built and the finite element method simulations were carried out to model the cathode voltage drop (CVD), the current distribution and, the effect of geometrical parameters on the CVD. The objective of the study was to quantify the drop in the CVD for different cathode assembly design. Flat- and inclined-interface carbon block top-surface and a copper insert versus the conventional insert-free designs were simulated with a myriad of other geometrical parameters to optimise the design. The results informed about the optimum insert positioning to about 75 mm from the collector base and the energy saving possibilities due to reduction in the CVD with a cathode design with inclined-interface carbon block and copper insert in the collector bar.  相似文献   
998.
The stability of an Al2O3 reinforcement in TIMETAL 21S has been investigated by annealing diffusion couples and consolidated fiber composites at 1100 °C, 900 °C, and 750 °C. Diffusion couple studies indicate that γ-TiAl, α 2-Ti3Al, and α-Ti(Al,O) phases can form upon annealing above the β transus of TIMETAL 21S, but γ-TiAl, α 2-Ti3Al, and a ternary T phase form during annealing below the β transus. The phases developed during diffusional interaction define a diffusion path between TIMETAL 21S and Al2O3. A coating of Nb, Mo, or Ta between TIMETAL 21S and Al2O3 acts as a diffusion barrier, but the coatings can diffuse into TIMETAL 21S at high temperature. In agreement with a kinetics analysis, a 2-μm-thick interface coating of Nb, Mo, or Ta in the TIMETAL 21S/Al2O3 composite can prevent the reaction during processing (2 hours at 850 °C or 900 °C) with no detectable diffusion into the matrix. If there are imperfections such as pinholes or cracks present in the diffusion barrier, the reaction quickly starts at the interface and does not remain confined at the imperfection; rather, it progresses along the interface. The mechanism for progressive development of interface reaction at a discontinuity in the diffusion barrier has been proposed. The analysis of the diffusional interface reactions in this work has identified some of the governing design concepts for development of robust high-temperature titanium-based composites.  相似文献   
999.
Multimedia Tools and Applications - COVID-19 disease is a major health calamity in twentieth century, in which the infection is spreading at the global level. Developing countries like Bangladesh,...  相似文献   
1000.

This paper investigates the combined effect of actuator saturation and time-delay on load frequency control (LFC) of a wind-integrated power system (WIPS). Actuator saturation is represented in two different approaches such as polytopic and sector bounding. Delay-discretization-based sliding mode \(H_{\infty }\) control approach is proposed to design a novel LFC scheme. The proposed control scheme requires present as well as delayed states information as input to the controller. This requirement of control scheme is fulfilled by adopting a finite known delay. This finite known delay used in controller design is discretized into delay intervals. Lyapunov–Krasovskii functional is defined for each delay interval, and \(H_{\infty }\) stabilization criteria for the closed loop WIPS are derived in linear matrix inequality framework using Wirtinger-based inequality. The proposed control scheme is tested by considering a numerical example of two-area WIPS.

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