Historical review of Tetrigidae: Cladonotinae – from Bolívar to Tumbrinck

U radu se sistematski obrađuje povijest taksonomije širokonosnih trnovratki (Tetrigidae: Cladonotinae). Obrađeni su najznačajniji znanstvenici koji su proučavali ovu potporodicu: I. Bolívar, J. L. Hancock, K. Günther i J. Tumbrinck. Dan je pregled izmjena taksonomije potporodice od njenog osnivanja do danas. Na primjerima su iznesene greške u sistematici koje su do danas ispravljene, te se stavlja naglasak na postojeće probleme u sistematici potporodice. Dan je kritički osvrt na današnje stanje u sistematici, te se ukazuje na nedostatak temeljitih istraţivanja potporodice.In this paper I give historical review of taxonomical research in Tetrigidae: Cladonotinae. Paper gives insight into most noteable researches in this field: I. Bolívar, J. L. Hancock, K. Günther and J. Tumbrinck. I represent taxonomical changes in subfamily from its foundation to this day. Examples of historical systematic mistakes are given, and accent is made on still existing problems in subfamily systematic. In this paper I present a critical opinion on today's taxon systematics and indicate the lack of thorough research on this subfamily

Investigation of co2 diluted methane and propane swirling premixed flames using ch* chemiluminescence imaging

Utilization of hydrocarbon gaseous fuels, such as biogas, landfill gas and others, is a valuable contribution to sustainable energy production and climate changing control. The presence of CO2 in these gases decreases heat of combustion, flame temperature, flame speed and can induce flame blow-off and combustion instabilities. In order to better understand the problem, flame geometry and location was investigated using chemiluminescence (CH*) imaging technique. Combustion took place in a purposely built, lean, premixed, unconfined swirl burner, fueled by methane and propane diluted with CO2. The fuel type, air-to-fuel equivalence ratio and CO2 content were chosen as the independent variables. The CH* imaging by means of a commercial CCD camera, fitted with an optical filter, was used for flame investigation. The analysis of images showed that the CH* emission intensity, flame geometry and location were remarkably affected by the fuel type and the air-to-fuel equivalence ratio, while the CO2 dilution was of minor importance

Investigation of co2 diluted methane and propane swirling premixed flames using ch* chemiluminescence imaging

Utilization of hydrocarbon gaseous fuels, such as biogas, landfill gas and others, is a valuable contribution to sustainable energy production and climate changing control. The presence of CO2 in these gases decreases heat of combustion, flame temperature, flame speed and can induce flame blow-off and combustion instabilities. In order to better understand the problem, flame geometry and location was investigated using chemiluminescence (CH*) imaging technique. Combustion took place in a purposely built, lean, premixed, unconfined swirl burner, fueled by methane and propane diluted with CO2. The fuel type, air-to-fuel equivalence ratio and CO2 content were chosen as the independent variables. The CH* imaging by means of a commercial CCD camera, fitted with an optical filter, was used for flame investigation. The analysis of images showed that the CH* emission intensity, flame geometry and location were remarkably affected by the fuel type and the air-to-fuel equivalence ratio, while the CO2 dilution was of minor importance

The Crystallographic Orientation and Surface Modification Effects in Electrocatalysis

A paramount role of surface structure and composition on the kinetics of electrocatalytic reactions has been realized with the establishment of electrocatalysis as a science. Consequently, a variation in the surface structure, and a modification of surface composition is expected to result in a considerable alternation of the electrocatalytic properties of electrodes

Analysis of the performance of a low-power atmospheric burner for gas appliances for households and their impact on the emission and stability of the burner

The paper presents results of theoretical numerical research dealing with CO and NOx emission performed in the process of optimization of the performance of low-power atmospheric burners. The theoretical part of this paper, whose main goals were better understanding of the complex issues of methodology and establishment of performance prediction and optimization of low-power atmospheric gas burner included numerical variation of independent parameters, such as burner geometry, the coefficients of primary and secondary air and different gaseous fuels including biogas. The findings of theoretically obtained performance prediction and optimization of atmospheric burners were experimentally investigated in purpose built test rigs for a number of variable parameters. The obtained results fully justified the proposed models of performance prediction and burner optimization

Iz starije srpske logike

In this pa­per we aim to pin­po­int so­me of the key mar­kers of the de­velop­ment of lo­gic in Ser­bia, star­ting from the fo­un­ding of the Lyce­um in 1836 un­til the end of the 19th cen­tury. Our main goal is to un­der­li­ne the ro­le that Lju­bo­mir Ne­dić, a phi­lo­sop­her and li­te­rary cri­tic, had in this con­text. Alt­ho­ugh he did not le­a­ve any ori­gi­nal con­tri­bu­ti­ons in lo­gic, Ne­dić played a sig­ni­fi­cant part by ex­po­sing con­tem­po­rary re­sults in symbo­lic lo­gic, which we­re to lead, thro­ugh Fre­ge’s la­ter work, to the cre­a­tion of mo­dern lo­gic

Analysis of the performance of a low-power atmospheric burner for gas appliances for households and their impact on the emission and stability of the burner

The paper presents results of theoretical numerical research dealing with CO and NOx emission performed in the process of optimization of the performance of low-power atmospheric burners. The theoretical part of this paper, whose main goals were better understanding of the complex issues of methodology and establishment of performance prediction and optimization of low-power atmospheric gas burner included numerical variation of independent parameters, such as burner geometry, the coefficients of primary and secondary air and different gaseous fuels including biogas. The findings of theoretically obtained performance prediction and optimization of atmospheric burners were experimentally investigated in purpose built test rigs for a number of variable parameters. The obtained results fully justified the proposed models of performance prediction and burner optimization

Potentials for usage of significantly reduced chemical mechanisms in numerical modeling of combustion processes

Rezultati numeričkih modeliranja prezentovani u ovom radu, deo su istraživanja laboratorije za sagorevanje Mašinskog fakulteta u Beogradu, sprovedenog u okviru FP6 projekta 'FlexHEAT', koji su zajedno realizovale institucije iz šest evropskih zemalja a koji je finansiran od strane Evropske unije (www.flexheat.uni-erlangen.de). U radu su prezentovani uporedni rezultati numeričkih proračuna kojima se simulira sagorevanje goriva na bazi metana (prirodni gas, srpski gas, biogas i sl), a koji su dobijeni korišćenjem eksperimentalno proverenog, kompletnog hemijskog mehanizma GRI 3.0 koji čini 325 hemijskih reakcija i odgovarajućeg veoma redukovanog hemijskog mehanizama, koga čine 2 hemijske reakcije (od kojih je jedna povratna) razvijenog na bazi dvostepenog C.K. Westbrook & F.L. Dryer (WD) modela. Rezultati su dobijeni upotrebom programskog paketa 'ChemKin' i determinišu oblast i mogućnost primene ovako značajno redukovanih hemijskih mehanizama u CFD proračunima, u situacijama kada kompleksnost samog strujanja sa hemijskim reakcijama kroz složene geometrije gorionika i peći ne dozvoljava upotrebu složenijih hemijskih mehanizama.The paper presents comparison of the results obtained in numerical research conducted, with the aim to simulate combustion of methane-based fuels like natural gas, Serbian gas, biogas, etc. Presented results were obtained using experimentally verified, full chemical mechanism GRI 3.0, with 325 chemical reactions, and using selected, very reduced chemical mechanism, with only two chemical reactions, based on two-step C.K. Westbrook & F.L. Dryer (WD) model. 'ChemKin' software was used for all numerical simulations of chemical kinetics and 'Fluent' for CFD analysis. The goal was to determine possibilities and application fields of this very reduced chemical mechanism in CFD calculations, especially in cases when flows with chemical reactions through complex geometry of burners and furnaces, disable usage of full mechanisms