199 research outputs found

    DESIGN A STRUCTURAL SOLUTION IMPOSITION SPINDLE AND PRESSING PUSHING

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    31 s., 8 s. příl. :obr., tab., grafy, výkresy +CD ROMTato bakalářská práce se zabývá návrhem konstrukčního řešení pro společné uchycení vřeten a lisovacích pouzder na karusel, co umožní rychlé seřízení párů vřeten a lisovacích pouzder vůči sobě na navíjecím automatu pro samonosné cívky. V práci je popsána stávající varianta uložení vřeten v lisovacích pouzdrech a jejich uložení na navíjecím automatu. Dále jsou předvedeny varianty nové, jejich principy a výhody, popřípadě nevýhody. Všechny varianty byly vymodelovány pomocí programu Creo Parametric 2.

    Poly(olefin sulfone)s

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    In this chapter, we introduce poly(olefin sulfone)s and review the recent progress on the photoinduced depolymerization of poly(olefin sulfone)s as well as their applications. Poly(olefin sulfone)s combined with photobase generators (PBGs) are depolymerized upon irradiation with light. A poly(olefin sulfone) is a 1:1 alternating copolymer of olefin monomer and sulfur dioxide in which the protons on the carbons adjacent to the sulfonyl groups can be readily abstracted by a base. This removal leads to a depolymerization chain reaction, resulting in incorporation of a photobase generating chromophore that can undergo a photoinduced unzipping reaction. During this reaction, the original olefin monomer and sulfur dioxide are regenerated from the primary chain of the poly(olefin sulfone). The photoinduced depolymerization of poly(olefin sulfone)s has been investigated for a wide variety of applications, including stereolithography, printable microcircuit fabrication, and removable adhesives

    A complete online SVM and case base reasoning in pipe defect dection with multisensory inspection gauge

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    An in-line inspection (ILI) robot has been considered an inevitable requirement to perform non-destructive testing methods efficiently and economically. The detection of flaws that could lead to leakages in buried concrete pipes has been a great concern to the oil and gas industry and water resource-based industry. The major problem is the difficulty in modeling the detection of cracks due to their irregularity and randomness that cannot be easily detected. Consequently, the use of an advanced modality system has emerged. Common defects detection systems favor non-destructive testing methods, which utilize specific sensory data. Only a few systems focus on fusing different types of sensory data. Moreover, the decision mechanism in this system required heavy-power consumption sensors with the configuration from the expertise domain. In addition, the outcome of the decision system is a consequence of rule-based settings rather than a mixture of learned features. This work covers the study of defect detection of non-destructive testing methods using fusion inspection sensors, light detection and ranging (LiDAR), and Optic sensors. The studies on ILI robots are reviewed to construct an efficient gauge. The prototype robot has been designed and successfully operated in a lab-scale environment. Ultimately, the study proposed a replacement for the standard expert system - in the branch of the CBR system, which is the crucial contribution of this thesis. Recent developments in Case-based Reasoning systems (CBR) have led to an interest in favoring machine learning (ML) approaches to replace traditional weighted distance methods. However, valuable information obtained through a training process was relinquished as transferring to other phases. As a result, the complete SVM-CBR system in this thesis concentrates on solving this gap by presenting an effective transferring mechanism from phase to phase. This thesis proposed a full pipeline integration of CBR using the kernel method designated with support vector machine. SVM technique is the primary classification engine for the combined sensory data. Since the system requires a learning SVM model to be invoked in every phase, the online learning mechanism is nominated to update the model when a new case adjoins effectively. The proposed full SVM-CBR integration has been successfully built into a pipe defect detection. The achieved result indicates a substantial improvement in transferring learning information accurately

    The Photorefractive Effect in Liquid Crystals

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    This chapter summarizes the state of the art of research regarding photorefractive liquid crystals. Photorefractive effect is of interest because it can be used to obtain dynamic holograms, based on interference between dual laser beams within a liquid crystal to generate a refractive index grating. This technique can be employed in numerous diffraction optics applications, such as optical amplifiers, phase-conjugate wave generators, 3D displays, novelty filters, and optical tomography. The photorefractive effect in liquid crystals is especially pronounced, and both ferroelectric and nematic liquid crystals have been researched for this purpose, with the former showing special promise in practical applications. As an example, ferroelectric liquid crystals have been found to readily produce a refractive index grating in conjunction with a significant gain and a formation time of 900 ms

    DESIGN OF A HIGH-SENSITIVITY DEVICE FOR DETECTING WEAK MAGNETIC FIELDS

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    An anti-serial fluxgate sensor configuration is proposed in this report. The design comprises two identical bilayer-rod fluxgate sensors connected anti-serially in a straight line. Each bilayer-rod sensor is constructed of an excitation coil and a pick-up coil wrapped around a core. The core material consists of Metglas ribbon, an amorphous alloy with high permeability, negligible hysteresis, and a high saturated magnetic field. The core is cut into a bar shape and uses double layers to enhance modulated flux density. A high sensitivity of 10 mV/Oe (with excitation of 45 kHz and 250 mA) is obtained experimentally with low noise of 1´10-5 Oe/Ö Hz at 1 Hz. In measurements of weak magnetic fields, the azimuth response indicates its vector feature. The proposed design is suitable for electronic compass and displacement applications

    Analyzing surface EMG signals to determine relationship between jaw imbalance and arm strength loss

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    BACKGROUND: This study investigated the relationship between dental occlusion and arm strength; in particular, the imbalance in the jaw can cause loss in arm strength phenomenon. One of the goals of this study was to record the maximum forces that the subjects can resist against the pull-down force on their hands while biting a spacer of adjustable height on the right or left side of the jaw. Then EMG measurement was used to determine the EMG-Force relationship of the jaw, neck and arms muscles. This gave us useful insights on the arms strength loss due to the biomechanical effects of the imbalance in the jaw mechanism. METHODS: In this study to determine the effects of the imbalance in the jaw to the strength of the arms, we conducted experiments with a pool of 20 healthy subjects of both genders. The subjects were asked to resist a pull down force applied on the contralateral arm while biting on a firm spacer using one side of the jaw. Four different muscles – masseter muscles, deltoid muscles, bicep muscles and trapezoid muscles – were involved. Integrated EMG (iEMG) and Higuchi fractal dimension (HFD) were used to analyze the EMG signals. RESULTS: The results showed that (1) Imbalance in the jaw causes loss of arm strength contra-laterally; (2) The loss is approximately a linear function of the height of the spacers. Moreover, the iEMG showed the intensity of muscle activities decreased when the degrees of jaw imbalance increased (spacer thickness increased). In addition, the tendency of Higuchi fractal dimension decreased for all muscles. CONCLUSIONS: This finding indicates that muscle fatigue and the decrease in muscle contraction level leads to the loss of arm strength

    Controllable Optical Properties of Multiple Electromagnetically Induced Transparency in Gaseous Atomic Media

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    The advent of electromagnetically induced transparency (EIT) offered a new coherent material with exotic and controllable optical properties. Although, studies on single-EIT are described in detail for single-EIT, however, extension from single- to multi- EIT is currently of current interest due to it gains advantages in multi-channel optical communication, waveguides for optical signal processing and multi-channel quantum information processing. In this work, we review recent research works concerning multi-EIT and some related applications, as controlling group velocity of light, giant Kerr nonlinearity, optical bistability. A special attention of the review also gives for analytical interpretations of EIT spectrum, its dispersion and related applications such as EIT enhanced Kerr nonlinearity and optical bistability to give physics insight. From experimental point of view, a latest development for measuring multi-EIT spectrum and its dispersion in hot medium is presented and compared to theoretical analytical representations

    The influence of economic factors on the sustainable energy consumption: evidence from China

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    Recently, sustainable energy consumption has been a significant factor in reducing environmental degradation due to the high economic growth, and this phenomenon demands more attention of scholars and policymakers. Thus, the current literature examines the impact of economic factors such as economic growth, foreign direct investment (FDI), inflation, and population growth on sustainable energy consumption (SEC), particularly in renewable energy consumption (REC) in China. This study used secondary data collection methods extracted from world development indicators (WDI), incorporating stationary tests like Phillips-Perron (PP) and Augmented Dickey-Fuller (ADF) to check the unit root of the constructs. The time-series data involved are from 1981 to 2019. The autoregressive distributed lag (ARDL) model was utilized to examine the association among the variables. The results indicated that economic growth, FDI, inflation, and population growth were positively associated with SEC in China. This study provides the guidelines to the policymakers to develop policies related to the SEC
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