Visose karšimo mašinose technologinės schemos yra panašios, ir karštuvai vieni nuo kitų skiriasi tik kai kuriais patobulintais bei papildomais mazgais. Tiekimo dalis visuose karštuvuose taip pat panaši. Tiektuvė - tai pirmoji kedenimo ir plakimo agregato mašina, kurios paskirtis yra presuoto pluošto skaidymas vidutinio dydžio kuokšteliais, pradinis jų maišymas, valymas ir tiekimas kitai agregato mašinai. Karštuvas mikropluoštas yra pastatytas su sunkiojo metalo konstrukcija ir tiesioginės pavaros sistemos siekiant užtikrinti didesnį darbo našumą visų tekstilės gaminių gamyboje ir neaustinių produktų, tokių kaip namų mados, baldai, patalynė, automobilių, filtravimas, pramonės gaminiai. Karštuvas mikropluoštas yra sudėtingas mechanizmų rinkinys, kurio tobulinimas yra neatsiejama dalis norint užtikrinti didesnį darbininkų saugumą ir įmonės darbo našumą. Šiame darbe aprašyto karštuvo mikropluošto paskirtis, pateikta techninė charakteristika, atlikta konstrukcinių variantų analizė, techniniai skaičiavimai, bei eksploataciniai reikalavimai. Projektuojant karštuvą mikropluoštą pasinaudota informacija AB "Neaustinių medžiagų fabrikas" techninė biblioteka, surinkta informacija apie įmonės technologinių įrenginių eksploatavimo bei remonto ypatumus. Pasinaudota Šiaulių universiteto Technologijos fakulteto biblioteka, katedros metodinė medžiaga, išnagrinėta mokslinė ir techninė literatūra, atlikta patentinė paieška, naudota interneto paieškos sistema. / Flow diagrams in all carding machines are similar and cards differ from each other only in some nodes that are improved or supplemental. Feeder part is also very similar in all cards. A feeder is the first machine of opening and scutching unit, the purpose of which is opening of compressed fibre into medium-size tufts, their initial mixing, cleaning and feeding into another machine of the unit. A microfiber carding machine includes heavy metal construction and direct drive systems to ensure greater labour productivity in manufacturing of all textile products as well as non-woven products, such as house fashion, furniture, bed linen, automobile, filtering, and industrial products. A microfiber carding machine is a complex set of mechanisms the improvement of which is an integral part of ensuring greater safety of the employees and productivity of the enterprise. This paper describes the purpose of a microfiber carding machine, presents its technical specification and carried out analysis of constructional variants, technical calculations, and operational requirements. When designing the microfiber carding machine information from technical library of joint stock company “Neaustinių medžiagų fabrikas” and collected information on peculiarities of maintenance and repairs of technological equipment of the company were used. Additionally, material available from Šiauliai University Technology Faculty library and methodological material from the department were used... [to full text]

The research objective was to develop a new competitively priced, high strength macrosynthetic fiber for concrete reinforcement. Mechanical bond properties were examined through aligned and inclined pullout testing. Variables involved in optimizing these properties included materials, fiber cross section, and other changes made through manufacturing processes. In addition to extensive pullout testing, improvements to fiber properties were explored through tensile testing, creep testing, and fiber performance in concrete mixtures. Practical considerations were also made, such as manufacturing processes, cost, and workability. Properties of synthetic microfibers were also considered for use in engineered cementitious composites. Synthetic macrofibers containing PVDF demonstrated high bond strength in pullout testing. Fibers demonstrating the highest performance in FRC testing were those with additional mechanical anchorage such as fibrillation or embossment. EVA as an additive did not exhibit increased interfacial bond, but further research was recommended. Further research on deformed fibers containing PVDF was also recommended.

The objective of this thesis was to explore the usefulness of all-fiber modulators for laser applications. The modulators were all based on refractive index change achieved in the core of the studied fiber- components, exploiting either the elasto-optic effect or the electro-optic effect. This was realized with the aid of electrodes inside the fiber cladding close to the core that provided either thermal stress in the core, or an electric field across the core. The electrodes consisted of low melting-point alloys, such as BiSn and AuSn, which were pushed into the hole-fiber, in the liquid state, which then solidified to form solid electrodes filling the entire hole. Together with an analyzer such as a polarizer or an interferometer the achieved refractive index modulation in the core could then be translated into an amplitude modulation of the guided light, which was subsequently utilized for switching fiber-lasers to generate cavity dumped, Q-switched, or mode-locked pulses. The fast rise/fall-time of a few nanoseconds for the elasto-optic devices was due to the fast thermal expansion of the electrodes. The maximum repetition rate, however, was limited to a few tens of kHz, due to the slow thermal processes for dissipation of the applied energy. The electro-optic fiber components, which displayed similar rise/fall-times on the other hand, showed a much higher cut-off frequency of 16 MHz. The electro-optic, all-fiber switch was also employed to select single pulses at 1 MHz repetition rate out of a 7 MHz train of pulses. Additionally, simulations using the finite element method were performed in order to gain insight and to explain the underlying processes of the observed response of a long-period grating written in a 2-hole fiber with electrodes, when applying HV-pulses to one of these. The thesis shows that the studied fiber-components show great potential of becoming complementary devices with high damage threshold for all-fiber laser applications in the future. / <p>QC 20121129</p>

Natural fibers, such as hemp and flax, are emerging as cheaper reinforcing fibers for polymer composites. Renew-ability, comparable specific properties, and biodegradability make natural fibers more attractive than glass fibers. Vacuum Assisted Resin Transfer Molding (VARTM) is widely used to manufacture medium-to-large sized composites. The non-woven mats used in VARTM must meet manufacturing (permeability) and structural (volume fraction (Vf), thickness, fiber orientation, properties) requirements. Unlike glass mats, natural fiber mats are not available commercially. Design and development of natural fiber mats require knowledge on the relationship among manufacturing, structure and properties of these mats and their composites. Developing this knowledge is the objective of this thesis. Effect of needle punch density on hemp fiber mat structure (areal density, Vf, fiber orientation distribution (FOD), thickness, permeability) was systematically studied. The FOD was characterized non-destructively using X-ray tomography. The Effect of consolidation pressure during composite manufacturing on its structure (Vf, thickness, FOD) was studied. The modulus and strength of needle-punched hemp mat – thermoset polyester composites, manufactured using VARTM and compression molding, were measured. A predictive model for these properties and a modeling approach for the evolution of FOD and thickness during mat manufacturing were developed and validated. The results of these studies were used to understand the relationship. The modulus and the strength of the composites were significantly influenced by the Vf and the FOD, the evolution of which during composite manufacturing depended on the consolidation pressure and the mat structure. The latter depended on mat manufacturing parameters, namely the punch density used to bind the fibers together and the areal density of the web of fibers formed during air laying, and the FOD in the web. The permeability of the mat decreased with increasing the punch density and was found to be a function of both the Vf and the FOD. Despite this, the manufacturing of composite was not adversely affected, and the tensile modulus increased with punch density. The mat composite was modeled as an equivalent laminate, whose lay-up was determined using its FOD. The properties of equivalent laminate that was predicted using lamination theory compared well with the experimental results.

Natural fibers, such as hemp and flax, are emerging as cheaper reinforcing fibers for polymer composites. Renew-ability, comparable specific properties, and biodegradability make natural fibers more attractive than glass fibers. Vacuum Assisted Resin Transfer Molding (VARTM) is widely used to manufacture medium-to-large sized composites. The non-woven mats used in VARTM must meet manufacturing (permeability) and structural (volume fraction (Vf), thickness, fiber orientation, properties) requirements. Unlike glass mats, natural fiber mats are not available commercially. Design and development of natural fiber mats require knowledge on the relationship among manufacturing, structure and properties of these mats and their composites. Developing this knowledge is the objective of this thesis. Effect of needle punch density on hemp fiber mat structure (areal density, Vf, fiber orientation distribution (FOD), thickness, permeability) was systematically studied. The FOD was characterized non-destructively using X-ray tomography. The Effect of consolidation pressure during composite manufacturing on its structure (Vf, thickness, FOD) was studied. The modulus and strength of needle-punched hemp mat – thermoset polyester composites, manufactured using VARTM and compression molding, were measured. A predictive model for these properties and a modeling approach for the evolution of FOD and thickness during mat manufacturing were developed and validated. The results of these studies were used to understand the relationship. The modulus and the strength of the composites were significantly influenced by the Vf and the FOD, the evolution of which during composite manufacturing depended on the consolidation pressure and the mat structure. The latter depended on mat manufacturing parameters, namely the punch density used to bind the fibers together and the areal density of the web of fibers formed during air laying, and the FOD in the web. The permeability of the mat decreased with increasing the punch density and was found to be a function of both the Vf and the FOD. Despite this, the manufacturing of composite was not adversely affected, and the tensile modulus increased with punch density. The mat composite was modeled as an equivalent laminate, whose lay-up was determined using its FOD. The properties of equivalent laminate that was predicted using lamination theory compared well with the experimental results.

Optical fiber sensors have been intensively studied and successfully employed in various human social activities and daily living, such as industrial production, civil engineering, medicine, transportation, national defense and so on. According to different structures, optical sensors could be divided into various categories. This thesis focuses on studying different kinds of in-line fiber Mach-Zehnder interferometers, which have played an important role among the optical interferometric fiber sensors. The structure composition, fabrication process, physical principle and practical applications of two novel in-line fiber Mach-Zehnder interferometers are proposed and discussed in detail in this work. The tapered bend-insensitive fiber Mach-Zehnder interferometer (BIF-MZI) is firstly fabricated and used as a fiber vibrometer. The unique double-cladding structure of bend-insensitive fiber not only provides higher mechanical strength to the sensor, but also guarantees a more uniform transmission spectrum， since only a few inner-cladding modes are left interfering with the core mode. A high sensitivity and fast response intensity demodulation scheme is employed by monitoring the power fluctuation of the BIF-MZI at the operation wavelength. Both damped and continuous vibrations are detected using the proposed sensor. It is demonstrated that this sensor responses to an extremely wide range of frequencies from 1 Hz up to 500 kHz with high signal-to-noise ratios (SNRs). The discrimination of temperature and axial strain is realized based on the dispersion effects of high-order-mode fiber (HOMF) by forming a single mode fiber-high-order-mode fiber-single mode fiber (SMF-HOMF-SMF) structure based in-line Mach-Zehnder interferometer. Unlike some kinds of in-line MZIs such as tapered and core–offset structures whose cladding modes are excited with different types under changing temperature and strain circumstances, the HOMF is capable of supporting three stable core modes, which guarantees a reliable and repeatable measurements within a large temperature or strain range. A new method based on the fast Fourier transform (FFT) is employed to analyze the mode couplings and their chromatic dispersion and intermodal dispersion properties in HOMF. The strong dispersion effects lead to a multi-peak feature in the spatial frequency spectrum. It is found that peaks that denote the waveform periods at positions that are beyond the critical wavelength possess highly sensitive and distinct phase responses to external disturbances, which provides the possibility to realize the discrimination measurements with high sensitivities and smaller errors by selecting appropriate peaks. The phase demodulation scheme is applied to quantify the temperature and strain changes in terms of phase shifts. Appropriate peak selections according to the practical needs would provide an easy access for applications where more than two parameters are required to be discriminated.

Fiber optic sensors are designed to measure various parameters. The distributed fiber optics sensor has been a very promising candidate for the structural health monitoring. In this thesis, we characterized LEAF (Large Effective Area Fiber) fiber’s Brillouin scattering spectrum and investigated its potentiality for the distributed Brillouin temperature and strain sensor. Optical fibers with complex refractive index profiles are applied to improve the Brillouin threshold by varying the Brillouin linewidth. As LEAF fiber has a modified refractive index profile, we investigated its Brillouin linewidth’s dependence on the square of the pump light’s frequency. We verified the Brillouin frequency’s variation with input SOP experimentally for LEAF fiber in the spontaneous regime. This sets a limitation for the frequency resolution of distributed Brillouin sensors. We also realized a simultaneous temperature and strain sensor with LEAF fiber applying the Brillouin optical time domain analysis. Based on the direct detection of LEAF beat frequencies, a simultaneous strain and temperature sensor was demonstrated.

This thesis reports the research and industry-related works carried out from the development of a fibre-optic strain sensor system for Civil Engineering applications. A sensor system consists of a number of core components, including the sensing element, interrogation/demodulation, multiplexing, signal processing and hardware equipment. In the process of development, a number of issues have been identified and investigated, which resulted in the improvement of the system performance, as well as the proposal of new techniques for the sensor system. First, an improved demodulation technique for a type of sensor, namely the fibre Fizeau interferometer (FFI), is presented. The technique is based on the improvement of the Fourier transform peak detection method, which suffers severely from the poor resolution and accuracy of finding the sensor cavity length. The improvement over the original method has been compared and verified through simulations and experiments. Second, a simultaneous demodulation technique for multiplexed FFI and fibre Bragg grating (FBG) sensors using the discrete wavelet transform (DWT) is proposed. Third, a multiplexing technique using amplitude-modulated chirped FBGs and the DWT is proposed. These two proposed techniques have been demonstrated experimentally through strain measurements. The strain resolution, crosstalk and limitations are investigated. In addition, simultaneous quasi-static strain and temperature sensing of different metal plates are performed. Fibre-optic sensors have found numerous applications in different areas. In this thesis, the use of FBG sensors in Civil Engineering applications is demonstrated in four experimental studies, including: (i) long-term measurement of drying shrinkage and creep of structural grade concrete; (ii) simultaneous measurement of shrinkage and temperature of reactive powder concrete (RPC) at early-age; (iii) measurement of coefficients of thermal expansion of cement mortar and RPC; and (iv) field-trial on the strain monitoring of the world?s first RPC road bridge. In addition, the experimental and practical issues of using FBG sensors are considered.

Thesis (M.S.)--Missouri University of Science and Technology, 2008. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed March 31, 2008) Includes bibliographical references (p. 33-36).

Thesis (Ph.D.)--Tufts University, 2001. / Adviser: Chris Davis. Submitted to the Dept. of Electrical Engineering. Includes bibliographical references (leaves 94-101). Access restricted to members of the Tufts University community. Also available via the World Wide Web;