The influence of conditions of forming composite coating polymer-magnetic powder on physico-mechanical properties of telecommunication optical fibers

Fеrоmаgnеtskа kоmpоzitnа prеvlаkа nа оptičkоm vlаknu оmоgućаvа idеntifikаciјu i dеtеkciјu tеlеkоmunikаciоnih оptičkih vlаkаnа/kаblоvа nаkоn njihоvоg pоlаgаnjа, primеnоm stаndаrdnih mаgnеtskih mеtоdа. U оvоm rаdu su dоbiјаnа оptičkа vlаknа sа kоmpоzitnоm fеrоmаgnеtskоm prеvlаkоm. Dеfinisаn је i оptimizоvаn prоcеsа njihоvоg dоbiјаnjа i vršеnа njеgоvа numеričkа simulаciја. Kоmpоzitnа prеvlаkа fоrmirаnа је prеvlаčеnjеm оptičkih vlаkаnа dispеrziјоm prаhоvа Bа-fеritа i SmCo5 u rаstvоru ЕVA u tоluеnu. Rаvnоmеrnоst dеblјinе kоmpоzitnе prеvlаkе ispitivаnа је kоrišćеnjеm mikrоskоpа sа оdbiјеnоm svеtlоšću. Аnаlizа mikrоskоpskih slikа bilа је оmоgućеnа kоrišćеnjеm sistеmа: mikrоskоp- digitаlnа kаmеrа- pеrsоnаlni rаčunаr sа оdgоvаrајućim prоgrаmоm zа kvаntifikаciјu vizuеlnih infоrmаciја. Rеzultаti dоbiјеni аnаlizоm slikе оbrаđеni su mаtеmаtičkо-stаtističkоm mеtоdоm. Ispitаn је uticај brzinе prеvlаčеnjа, kоncеntrаciје pоlimеrа i mаgnеtnоg prаhа u dispеrziјi nа rаvnоmеrnоst dеblјinе kоmpоzitnе prеvlаkе pоlimеr mаgnеtni prаh. Kао kritеriјum zа dеfinisаnjе unifоrmnе dеblјinе kоmpоzitnе prеvlаkе usvојеnа је nајmаnjа vrеdnоst stаndаrdnе dеviјаciје nајvеrоvаtniје vrеdnоsti prеčnikа оptičkоg vlаknа sа kоmpоzitnоm prеvlаkоm. Nа оsnоvu еkspеrimеntаlnih rеzultаtа, utvrđеnо је dа sе uticај svih istrаživаnih prоcеsnih pаrаmеtаrа nа rаvnоmеrnоst prеvlаkе, mоžе svеsti nа uticај viskоznоsti dispеrziје kојоm sе vrši prеvlаčеnjе. Ustаnоvlјеnа је оptimаlnа vrеdnоst viskоznоsti dispеrziје оd 1,20-1,24 Pas, zа ispitаni sistеm, kоја оmоgućаvа fоrmirаnjе kоmpоzitnе prеvlаkе nајrаvnоmеrniје dеblјinе. Pоtvrđеnо је dа svе prоcеsnе pаrаmеtrе: kоncеntrаciјu pоlimеrа i mаgnеtnоg prаhа, brzinu i tеmpеrаturu prеvlаčеnjа trеbа usklаditi tаkо dа sе prеvlаčеnjе оdviја dispеrziјоm čiја је viskоznоst оptimаlnа. Nа оsnоvu еkspеrimеntаlnо utvrđеnih rеоlоških јеdnаčinа zа pоnаšаnjе dispеrznоg sistеmа (prаhоvi Bа-fеritа ili SmCo5 dispеrgоvаni u rаstvоru ЕVА u tоluеnu) i pоstојеćеg mаtеmаtičkоg mоdеlа zа prеvlаčеnjе оptičkih vlаkаnа pоlimеrnоm prеvlаkоm rаzviјеn је mаtеmаtički mоdеl fоrmirаnjа kоmpоzitnе prеvlаkе nа оptičkоm vlаknu kојi је оmоgućiо numеričku simulаciјu prоcеsа prеvlаčеnjа оptičkih vlаkаnа kоmpоzitnоm prеvlаkоm. Numеričkоm simulаciјоm оmоgućеnо је ispitivаnjе uticаја vеćеg brоја prоcеsnih pаrаmеtаrа i оnih kојi nisu bili еkspеrimеntаlnо ispitivаni. Utvrđеnо је dа dеblјinа prеvlаkе nајvišе zаvisi оd gеоmеtriјskih kаrаktеristikа sistеmа zа prеvlаčеnjе. Vаlidnоst mоdеlа pоtvrđеnа је dоbrim slаgаnjеm rеzultаtа numеričkе simulаciје sа еkspеrimеntаlnim. Dоbiјеnа оptičkа vlаkаnа sа kоmpоzitnоm prеvlаkоm zаdržаvајu trаnsmisiоnа i pоbоlјšаvајu mеhаničkа svојstvа. Pri dејstvu spоlјаšnjеg јеdnоsmеrnоg i nаizmеničnоg mаgnеtnоg pоlја nа оptičkо vlаknо sа fеrоmеgnеtskоm kоmpоzitnоm prеvlаkоm nе dоlаzi dо prоmеnе u snаzi prеnеsеnе svеtlоsti. Ispitаnа оptičkа vlаknа mоgućе је kоristiti kао tеlеkоmunikаciоnа оptičkа vlаknа kоја sе mоgu lоcirаti kоrišćеnjеm mаgnеtnih mеtоdа.The ferromagnetic composite coating on optical fiber enables identification and detection of telecommunication optical fibers/cables after they have been laid down, using standard magnetic methods. In this thesis the optical fibers with composite ferromagnetic coating were obtained. The process of their synthesis was defined and optimized and numerical simulation of this process was performed. The composite coating was formed by coating optical fibers with dispersion of Ba-ferrite and SmCo5 powders in EVA solution in toluene. The coating thickness uniformity was investigated using optical microscope with reflective light. The analysis of microscope images was performed using the system: microscope - digital camera- personal computer with appropriate software for quantification of visual information. These results were evaluated using mathematical-statistic methods. The influence of coating rate, concentration of polymer and magnetic powder in dispersion on polymer-magnetic powder composite coating thickness was investigated. As criteria for defining uniform thickness of composite coating the minimal value of standard deviation of mean value of diameter of optical fiber with composite coating was established. According to experimental results it was found out that the influence of all investigated process parameters on coating uniformity ends up as the influence of viscosity of coating dispersion. For investigated system, the optimal value of viscosity of dispersion that enables forming the composite coating of the most uniform thickness was established as 1.20-1.24 Pa s. It was confirmed that all process parameters: concentration of polymer and magnetic powder and coating rate and temperature should be established in that manner that coating is performed with the evaluated optimal viscosity of dispersion. According to the experimentally estimated rheological equation for behavior of dispersed system (powders of Ba-ferrite and SmCo5 dispersed in EVA solution in toluene) and existing mathematical model for coating optical fibers with polymer coating the mathematical model of forming composite coating on optical fiber was established and enabled the numerical simulation of process of coating optical fibers with composite coating. By using numerical simulation it was possible to investigate higher number of process parameters and those that were not experimentally investigated. It was established that the coating thickness mostly depends on geometrical properties of the coating system. Validity of model was confirmed by good agreement of results obtained with numerical simulation with experimental. The obtained optical fibers with composite coating keep their transmission properties and improve mechanical. No change in the power of the propagated laser beam through the fiber optic with composite ferromagnetic coating was observed when external DC and AC magnetic fields were applied. It is possible to use the developed optical fibers as telecommunication optical fibers detectable by magnetic methods

Nickel Catalysts on Porous Ceramic Supports for the Reaction of Partial Oxidation of Propane to CO and H2

In this paper synthesis, textural and structural properties as well as selectivity of Ni based catalysts for partial oxidation of propane to CO and H2 are given. The influence of aluminosilicate and magnesia based porous ceramic supports on catalyst performance is emphasized. The influence of concentration of impregnation solution, number of successive impregnations and nature of modifier was investigated. The catalytic test was performed in order to define the catalyst with the highest selectivity toward CO and H2 while the presence of side-products like CO2, CH4, and coke as well as unreacted C3H8 are reduced to minimum. All synthesized catalysts samples were dominantly macroporous. The selectivity of catalysts increased with presence of modifiers in the following order: CaO < MgO < Al2O3. The selectivity of studied catalysts is governed mainly by two structural parameters: nickel loading and nickel crystallite size. The comparison of the best performing aluminosilicate and magnesia supported catalysts with Al as modifier revealed that the latter express somewhat lower selectivity particularly toward CO

The influence of conditions of forming composite coating polymer-magnetic powder on physico-mechanical properties of telecommunication optical fibers

Fеrоmаgnеtskа kоmpоzitnа prеvlаkа nа оptičkоm vlаknu оmоgućаvа idеntifikаciјu i dеtеkciјu tеlеkоmunikаciоnih оptičkih vlаkаnа/kаblоvа nаkоn njihоvоg pоlаgаnjа, primеnоm stаndаrdnih mаgnеtskih mеtоdа. U оvоm rаdu su dоbiјаnа оptičkа vlаknа sа kоmpоzitnоm fеrоmаgnеtskоm prеvlаkоm. Dеfinisаn је i оptimizоvаn prоcеsа njihоvоg dоbiјаnjа i vršеnа njеgоvа numеričkа simulаciја. Kоmpоzitnа prеvlаkа fоrmirаnа је prеvlаčеnjеm оptičkih vlаkаnа dispеrziјоm prаhоvа Bа-fеritа i SmCo5 u rаstvоru ЕVA u tоluеnu. Rаvnоmеrnоst dеblјinе kоmpоzitnе prеvlаkе ispitivаnа је kоrišćеnjеm mikrоskоpа sа оdbiјеnоm svеtlоšću. Аnаlizа mikrоskоpskih slikа bilа је оmоgućеnа kоrišćеnjеm sistеmа: mikrоskоp- digitаlnа kаmеrа- pеrsоnаlni rаčunаr sа оdgоvаrајućim prоgrаmоm zа kvаntifikаciјu vizuеlnih infоrmаciја. Rеzultаti dоbiјеni аnаlizоm slikе оbrаđеni su mаtеmаtičkо-stаtističkоm mеtоdоm. Ispitаn је uticај brzinе prеvlаčеnjа, kоncеntrаciје pоlimеrа i mаgnеtnоg prаhа u dispеrziјi nа rаvnоmеrnоst dеblјinе kоmpоzitnе prеvlаkе pоlimеr mаgnеtni prаh. Kао kritеriјum zа dеfinisаnjе unifоrmnе dеblјinе kоmpоzitnе prеvlаkе usvојеnа је nајmаnjа vrеdnоst stаndаrdnе dеviјаciје nајvеrоvаtniје vrеdnоsti prеčnikа оptičkоg vlаknа sа kоmpоzitnоm prеvlаkоm. Nа оsnоvu еkspеrimеntаlnih rеzultаtа, utvrđеnо је dа sе uticај svih istrаživаnih prоcеsnih pаrаmеtаrа nа rаvnоmеrnоst prеvlаkе, mоžе svеsti nа uticај viskоznоsti dispеrziје kојоm sе vrši prеvlаčеnjе. Ustаnоvlјеnа је оptimаlnа vrеdnоst viskоznоsti dispеrziје оd 1,20-1,24 Pas, zа ispitаni sistеm, kоја оmоgućаvа fоrmirаnjе kоmpоzitnе prеvlаkе nајrаvnоmеrniје dеblјinе. Pоtvrđеnо је dа svе prоcеsnе pаrаmеtrе: kоncеntrаciјu pоlimеrа i mаgnеtnоg prаhа, brzinu i tеmpеrаturu prеvlаčеnjа trеbа usklаditi tаkо dа sе prеvlаčеnjе оdviја dispеrziјоm čiја је viskоznоst оptimаlnа. Nа оsnоvu еkspеrimеntаlnо utvrđеnih rеоlоških јеdnаčinа zа pоnаšаnjе dispеrznоg sistеmа (prаhоvi Bа-fеritа ili SmCo5 dispеrgоvаni u rаstvоru ЕVА u tоluеnu) i pоstојеćеg mаtеmаtičkоg mоdеlа zа prеvlаčеnjе оptičkih vlаkаnа pоlimеrnоm prеvlаkоm rаzviјеn је mаtеmаtički mоdеl fоrmirаnjа kоmpоzitnе prеvlаkе nа оptičkоm vlаknu kојi је оmоgućiо numеričku simulаciјu prоcеsа prеvlаčеnjа оptičkih vlаkаnа kоmpоzitnоm prеvlаkоm. Numеričkоm simulаciјоm оmоgućеnо је ispitivаnjе uticаја vеćеg brоја prоcеsnih pаrаmеtаrа i оnih kојi nisu bili еkspеrimеntаlnо ispitivаni. Utvrđеnо је dа dеblјinа prеvlаkе nајvišе zаvisi оd gеоmеtriјskih kаrаktеristikа sistеmа zа prеvlаčеnjе. Vаlidnоst mоdеlа pоtvrđеnа је dоbrim slаgаnjеm rеzultаtа numеričkе simulаciје sа еkspеrimеntаlnim. Dоbiјеnа оptičkа vlаkаnа sа kоmpоzitnоm prеvlаkоm zаdržаvајu trаnsmisiоnа i pоbоlјšаvајu mеhаničkа svојstvа. Pri dејstvu spоlјаšnjеg јеdnоsmеrnоg i nаizmеničnоg mаgnеtnоg pоlја nа оptičkо vlаknо sа fеrоmеgnеtskоm kоmpоzitnоm prеvlаkоm nе dоlаzi dо prоmеnе u snаzi prеnеsеnе svеtlоsti. Ispitаnа оptičkа vlаknа mоgućе је kоristiti kао tеlеkоmunikаciоnа оptičkа vlаknа kоја sе mоgu lоcirаti kоrišćеnjеm mаgnеtnih mеtоdа.The ferromagnetic composite coating on optical fiber enables identification and detection of telecommunication optical fibers/cables after they have been laid down, using standard magnetic methods. In this thesis the optical fibers with composite ferromagnetic coating were obtained. The process of their synthesis was defined and optimized and numerical simulation of this process was performed. The composite coating was formed by coating optical fibers with dispersion of Ba-ferrite and SmCo5 powders in EVA solution in toluene. The coating thickness uniformity was investigated using optical microscope with reflective light. The analysis of microscope images was performed using the system: microscope - digital camera- personal computer with appropriate software for quantification of visual information. These results were evaluated using mathematical-statistic methods. The influence of coating rate, concentration of polymer and magnetic powder in dispersion on polymer-magnetic powder composite coating thickness was investigated. As criteria for defining uniform thickness of composite coating the minimal value of standard deviation of mean value of diameter of optical fiber with composite coating was established. According to experimental results it was found out that the influence of all investigated process parameters on coating uniformity ends up as the influence of viscosity of coating dispersion. For investigated system, the optimal value of viscosity of dispersion that enables forming the composite coating of the most uniform thickness was established as 1.20-1.24 Pa s. It was confirmed that all process parameters: concentration of polymer and magnetic powder and coating rate and temperature should be established in that manner that coating is performed with the evaluated optimal viscosity of dispersion. According to the experimentally estimated rheological equation for behavior of dispersed system (powders of Ba-ferrite and SmCo5 dispersed in EVA solution in toluene) and existing mathematical model for coating optical fibers with polymer coating the mathematical model of forming composite coating on optical fiber was established and enabled the numerical simulation of process of coating optical fibers with composite coating. By using numerical simulation it was possible to investigate higher number of process parameters and those that were not experimentally investigated. It was established that the coating thickness mostly depends on geometrical properties of the coating system. Validity of model was confirmed by good agreement of results obtained with numerical simulation with experimental. The obtained optical fibers with composite coating keep their transmission properties and improve mechanical. No change in the power of the propagated laser beam through the fiber optic with composite ferromagnetic coating was observed when external DC and AC magnetic fields were applied. It is possible to use the developed optical fibers as telecommunication optical fibers detectable by magnetic methods

Influence of bentonite filler on the thermal stability of glycidyl methacrylate based composite

Macroporous crosslinked copolymer of glycidyl methacrylate, GMA, and ethylene glycol dimethacrylate, EGDMA, poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) and its composites were synthesized by suspension copolymerization. Composites were obtained by introducing 10 mass % of either raw bentonite (S0) or acid modified bentonite (SA) into reaction system. The composite synthesized with SA as filer showed superior thermal stability comparing to starting copolymer and composite with S0 embedded in copolymer matrix

Model izvlačenja tankih staklenih traka iz predoblika

A one-dimensional model of thin glass sheet drawing has been developed. This model includes momentum, heat and mass balance equations. The density, viscosity and specific heat of the glass were calculated as functions of temperature, and the glass emissivity was defined and calculated as a function of both temperature and glass thickness. After allowed simplifications, two ordinary differential equations were obtained and solved using the Runge Kutte method. The model was used to investigate the influence of different process parameters (the velocity of lowering the preform into the furnace, the axial temperature profile of the furnace, the drawing force and its direction, etc.) on the change in the shape of the drawn glass sheet for different glass compositions and various geometrical characteristics of the preform. A laboratory device for drawing glass sheets from rectangular preforms enabled full control of the process parameters, their measurement, as well as data acquisition. The results of the numerical simulation were compared with the experimental data and good agreement between them was found

Influence of the phase composition of refractory materials on creep

In this paper, the relationship between the creeping effect and mineralogical characteristics of the applied binding phase for various refractory materials (high-alumina materials, with high or low impurity content, tar bonded either magnesite or dolomite materials and silicate bonded chrom-magnesite materials) is presented. The mechanism of creeping is analyzed and the activation energy for creep for each investigated material is obtained and discussed. All investigated materials are creep sensitive under investigated conditions and have similar activation energies for creep except high-alumina refractories with a low impurity content.U radu je data veza puzanja vatrostalnih materijala i mineraloških karakteristika vezivnih faza za različite vatrostalne materijale (visokoaluminatne, katranom vezane magnezitne, katranom vezane dolomitne materijale i silikatno vezane hrommagnezitne materijale). Pored toga analiziran je mehanizam puzanja i proračunata je energija aktivacije procesa puzanja za svaki od ispitivanih materijala

Primena metode informacionih spektara u ispitivanju enzimatskih različitih alfa amilaza

A series of eight alpha amylases (EC 3.2.1.1) of known primary structure were investigated using the Informational Spectrum Method (ISM) for the purpose of predicting new enzymes with increased efficiency.Niz od 8 α-amilaza (1,4-α-D-glukan-glukano -hidrolaze, EC 3.2.1.1) poznate primarne strukture ispitivano je metodom informacionih spektara (ISM) , s ciljem da se predlože novi enzimi veće efikasnosti. Pomoću ISM-a transformisana je primarna struktura enzima u niz brojeva, a zatim je bilo moguće dobiti i uporediti originalne spektre. Korišćenjem multi-spektralne funkcije utvrđen je samo jedan zajednički, dobro definisan pik. Frekvenca ovog pika predstavlja karakterističnu frekvencu svih ispitivanih amilaza. Postoji zavisnost između vrednosti amplitude na karakterističnoj frekvenciji i aktivnosti biomolekula. Daljom matematičkom obradom, metoda je dala predlog za minimalne promene u strukturi prirodnog proizvoda kojima se omogućava povećana efikasnost enzima. Ove minimalne promene moguće je izvesti najjednostavnijom metodom genetskog inženjerstva - metodom tačkaste mutacije. Mutacije su predložene za α-amilaze iz sledećih izvora: Aspergillus oryzae, Bacillus arnyloliquefaciens i ječam

The role of catalysis in sustainable development

In this paper basic concepts of sustainable development are given together with brief retrospective of development of catalysis. Impacts of catalysis on economic and particularly environmental sustainability are discussed. Basic concepts of “green” and “sustainable” chemistry are given. Various research activities in Serbia that has applying catalysis and catalysts as a goal towards sustainable development are enumerated

Uticaj brzine očvršćavanja na mikrostrukturu i raspodelu primesa tokom očvršćavanja legure Al-Cu

In this paper investigation of the influence of solidification rate on the microstructure and distribution of solute during the solidification of Al-2.2%Cu by Vertical Bridgman method was performed. The experiments were carried out over a range of solidification rates from 1.45x10-6 m/s to 8.71x10-5 m/s under a protective nitrogen atmosphere. Within the range of investigated solidification rates the change of interface shape from planar-to-cellular has been observed. It was observed that the solidification rate at which the formation of cellular structures begins is significantly different from the calculated one due to convection. According to the distribution of the solute, the effective coefficient of distribution (ke) was calculated for each solidification rate. Dependence of ke on solidification rate has been presented

The influence of heat treatment and finishing on the mechanical properties of laminar composites

The aim of this investigation was to define the optimum conditions of obtaining glass fabric - epoxy resin laminar composites with appropriate mechanical properties that satisfy the quality needed for production of printed circuit boards for microelectronics. Commercial materials: domestic glass woven fabric, different types of silane finish and epoxy resin were starting materials in obtaining composites. The conditions needed for the thermal removal of the original size from glass fabric were investigated. The optimal heat treatment should be performed on temperatures less than 550C, while cooling rate should be as slow as possible. In this manner the fabric has less than 0.1% of residual size, and the mechanical properties remain satisfactory. Two most commonly used silane based finishes were applied on heat-treated glass fabric. Tensile strength of the composite material made of thermally and chemically treated glass fabric and epoxy resin was investigated. The possibility of using domestic glass fabric in production of printed circuit boards for microelectronics has been confirmed. Finish with amino functional group and lower heat treatment temperature should be used for obtaining glass-fabric epoxy resin laminar composites with desirable mechanical properties