Tianjin Polytechnic University is a university in Tianjin, China under the municipal government. It is also referred to as TJPU. The university was founded in 1912 and currently has fourteen colleges on two campuses in the city. The old campus is located in the Hedong District , and the new one is in the Xiqing District . Wikipedia.
Shi W.,Tianjin Polytechnic University
IEEE Transactions on Fuzzy Systems | Year: 2014
In this paper, an indirect adaptive fuzzy control scheme is developed for a class of uncertain multi-input multi-output nonlinear systems with nonsymmetric control gain matrix and unknown control direction. The nonsymmetric control gain matrix is expressed as the sum of a symmetric matrix and a skew symmetric matrix, and the symmetric matrix, as well as the skew symmetric matrix, is approximated by fuzzy systems. By using the symmetric matrix decomposition technique, the estimated symmetric matrix is decomposed into the product of one diagonal matrix and two orthogonal matrixes. Based on the decomposition results, the adaptive fuzzy controller is developed to avoid the possible singularity problem and the parameter initialization problem. A robust control term is employed to compensate for the lumped errors, and a Nussbaum-type function is incorporated in the robust control term to deal with the unknown control direction. The proposed scheme guarantees that all the signals in the resulting closed-loop system are bounded and that the tracking errors converge asymptotically to zero. Two simulation examples are used to demonstrate the effectiveness of the proposed scheme. © 2013 IEEE.
Tianjin Polytechnic University | Date: 2016-07-06
A method for preparing a reinforced electrospinning nanofiber membrane, which performs alternate blending electrospinning by utilizing several thermoplastic polymer with a melting point at least 20C lower than that of the other component or thermoplastic polymer with low melting point, and non-thermoplastic polymer. Electrospun jets of several components are arranged along the movement direction of receiving device in forth-and-back, fibers are arranged randomly and alternatively. The blending spinning fiber membrane is post-treated with thermal calendering, and the hot-pressing temperature is slightly higher than that of starting melting temperature of the polymer with low melting point, time is 110 min, pressure is 120 MPa. After hot-pressing, the thermoplastic polymer with low melting point is partly melt and forms point bonding at the intersection of fibers, without clogging pores. This invention relates to an electrospun nanofiber membrane and a blending electrospinning device.
Tianjin Polytechnic University | Date: 2013-01-24
A preparation method of a homogeneous-reinforced PVDF hollow fiber membrane includes steps of: a) preparing a reinforced matrix membrane, wherein a PVDF hollow fiber membrane is utilized as the reinforced matrix membrane; b) preparing a PVDF casting solution, wherein mass fractions of the PVDF casting solution are: PVDF 620 wt %; hydrophilic polymers or hydrophilic inorganic particles 0.62 wt %; pore-forming agent 610 wt %; and solvent 6887.4 wt %; mixing the above solutes in a water bath with a temperature of 7090 C., dissolving for 34 h with stirring, then deaerating under vacuum for obtaining the uniform PVDF casting solution; and c) preparing the homogeneous-reinforced membrane; wherein the PVDF casting solution is uniformly coated on an outer surface of the reinforced matrix membrane through a spinning spinneret, then the reinforced matrix membrane is towed by a filament guide roller in such a manner that the hollow fiber forms a membrane, then the membrane passes through an air gap with a length of 520 cm and is immersed in ultrafiltered water for coagulation, in such a manner that the homogeneous-reinforced membrane is obtained; wherein a traction speed is 525 cm/(rmin).
Tianjin Polytechnic University | Date: 2011-03-01
A composition for preparation of a hollow fiber porous membrane including 40-60 wt. % a polymer matrix, 20-30 wt. % an organic mixed solution, and 20-40 wt. % a water-soluble substance. The polymer matrix is a polymer capable of dissolving in an organic solvent and melt processing. The organic mixed solution is a mixture comprising 60-90 wt. % a first liquid soluble to the polymer matrix and 10-40 wt. % a second liquid insoluble to the polymer matrix. The water-soluble substance is a water-soluble polymer, a low molecular weight water-soluble particle, or a mixture thereof. A method for producing the hollow fiber porous membrane using the composition including a) preparing the organic mixed solution, b) mixing the components of the composition, c) applying melt spinning, d) drawing, and e) washing. The hollow fiber membrane has high strength, large flux, and low cost.
Tianjin Polytechnic University | Date: 2015-02-02
Disclosed in the present invention is a benzocrown ether graft polymer with a lithium isotopic separation effect and a preparation method thereof. The polymer is a benzocrown ether graft polymer formed by the linkage of chemical bonds, which takes the main chain of a polymer containing chloromethyl group, chloroformyl group or hydroxyl group as main chain, and takes a benzocrown ether as pendant group. The preparation process of the polymer comprises the following steps: preparing polymer solution with certain concentration by dissolving a polymer containing chloromethyl group, chloroformyl group or hydroxyl group in a solvent; then blending a catalyst and a benzocrown ether containing carboxyl group or aldehydyl group and dissolving in the polymer solution containing hydroxyl group, or blending an acid-binding agent and a benzocrown ether containing amino group or hydroxyl group and dissolving in the polymer solution containing chloromethyl group or chloroformyl group, reacting at a certain temperature and for a certain time, linking the benzocrown ether to the main chain of polymer by chemical bonds, and precipitating by adding a precipitating agent to obtain the graft polymer. The grafting polymer has excellent characteristic of lithium isotopic separation.
Tianjin Polytechnic University | Date: 2013-01-24
A preparation method of a perfluorinated polymer hollow fiber membrane comprises: evenly mixing a first mixture that is mixed by a perfluorinated polymer, PS, a polymer additive, and a composite pore-forming agent; evenly mixing a second mixture that is mixed by the first mixture and an organic liquid; under 300 C.-350 C., processing the second mixture with a melt to spin by a twin-screw extruder; extruding a hollow fiber by a hollow fiber spinneret; dipping the hollow fiber membrane into deionized water for 48 hours; putting the hollow fiber membrane aired into a concentrated sulfuric acid to process with a sulfonation; washing the hollow fiber membrane by deionized water; and drying the hollow fiber membrane; in such a manner that the hydrophilic perfluorinated polymer hollow fiber membrane is obtained.
Tianjin Polytechnic University | Date: 2012-10-31
A robust design method for a textile-manufacturing-dedicated, high-efficient, energy-saving, multiphase asynchronous motor, includes the following steps: designating a motor; designating design method; designating design variables of the high-efficient, energy-saving, multiphase asynchronous motor; building mathematical models of each index respectively to constitute a robust design model with multiple indexes; building the controllable factor level table; selecting appropriate orthogonal table according to the number of the optimizing variables and the level number of each variable; building an inner orthogonal table for inner design; building an outer orthogonal table for outer design; computing the values of the output characteristics and signal to noise ratio of the experimental schemes determined by the inner and outer orthogonal tables; determining the optimal combination of parameters; going through tolerance design; drawing the parts of the textile-manufacturing-dedicated, high-efficient, energy-saving, multiphase asynchronous motor according to the optimal design scheme, wire-cutting the mold, dieing, laminating, coiling, inserting windings, dipping paint and assembling. Combining the actual operating characteristics of textile-manufacturing-dedicated motor, a high-efficient, energy-saving, multiphase asynchronous motor with stable performance, reliable operation and low cost is achieved. The motor achieves the optimal balance between the quality and cost, and enhances the market competitiveness.
Tianjin Polytechnic University | Date: 2013-03-21
The present invention provides a thermo-regulated fiber and a preparation method thereof by using a new polymeric phase-change material and adopting a new fiber preparation method, and the resulting thermo-regulated fiber has good thermo-regulating properties and a good thermal stability. The thermo-regulated fiber has a composite structure, and the cross-sectional structure is an sea-island type or a concentric sheath/core type, characterised in that the polymeric phase-change material is a polyethylene glycol n-alkyl ether (structural formula: H(OCH_(2)CH_(2))_(m)OC_(n)H2_(n+1)), where the repeating unit number m of the ethylene glycol is 1 to 100, the number n of carbon atoms in the n-alkyl is 11 to 30. The present invention further relates to a preparation method of a thermo-regulated fiber which includes one of the following processes: (1) A melt composite spinning process; (2) Solution composite spinning process; (3) Electrostatic solution composite spinning process. Further, the present invention is characterised as follows: (1) a new polymeric phase-change material polyethylene glycol n-alkyl ether is used; (2) Component A of the thermo-regulated fiber may form a continuous crystallization region; (3) The thermo-regulated fiber can be prepared in various forms by many preparation methods such as melt composite spinning, solution composite spinning and solution static composite spinning.
Tianjin Polytechnic University | Date: 2014-10-28
A hollow tubular oil absorbing material includes: a core formed by a spring, and an outer shell formed by a flat sponge wrapped at the spring; wherein the flat sponge is fixed at both ends of the spring; the flat sponge fully covers all the spring or is sealed at a first end; a connecting tube is connected at a second end of the spring for communicating with a vacuum pump; a graphene oxide layer is coated at the outer sponge. The graphene oxide layer on the flat sponge of hollow tubular oil absorbing material is formed by immersion and coating under negative pressure. Further the reduction of graphene oxide is performed with hydrazine hydrate steam and followed by washing and drying. Finally, a hollow tubular oil absorbing material with a spring core and an outer grapheme-coated sponge structure is obtained, which can be applied to continuous oil-water separation.
Tianjin Polytechnic University | Date: 2016-11-23
A method for preparing a homogeneous braid-reinforced (HMR) PPTA hollow fiber membrane combines PPTA hollow tubular braids with PPTA surface separation layer. The method includes following steps of: (1) preparing the PPTA hollow tubular braids, wherein the PPTA hollow tubular braids which are made from PPTA filament yarns are woven by a two-dimensional braided method, the outer diameter of the PPTA tubular braids is 1-2mm; (2) preparing the PPTA casting solution as the surface separation layer, wherein the 1-3wt% PPTA resin, 0-2wt% inorganic particles and 10-20wt% pore-forming agents are mixed into 75-89% inorganic acid solvent, stirred for 1-3 hours at 70C-90C to form homogeneous and transparent casting solution; and (3) preparing reinforced PPTA hollow fiber membrane, wherein the casting solution as the surface separation layer is evenly coated on the surfaces of the PPTA hollow tubular braids through spinneret, and they are immersed in a coagulation bath for solidified formation.