milovan jotanovic - Academia.edu (original) (raw)

Papers by milovan jotanovic

The authors of the paper are giving a detailed description of the operation principles of a one-s... more The authors of the paper are giving a detailed description of the operation principles of a one-stage and two-stage high-temperature heat pump. A computer programme was used to process the dependences of different evaporation temperatures regarding the heat flow, the heat pump strength and COP. An economic assessment of the investment into different heat pump designs at different evaporation temperatures of refrigerants was also conducted. Key-Words: -Heat transfer, high temperature heat pumps, economic analysis

The paper shows the potential benefit of using low temperature heat sources with high temperature... more The paper shows the potential benefit of using low temperature heat sources with high temperature pumps. Two-stage heat pumps with flash unit and heat exchanger are described. To determine the characteristic parameters of the twoheat pumps a computer program was designed, with which we could determine the dependence of COP and compressor pressure ratios from evaporating temperature. An economic analysis of the justification of the use of heat pumps was made.

Contemporary materials, Aug 31, 2011

In this paper the influence of carbon dioxide pressure on supercritical extraction of Salvia offi... more In this paper the influence of carbon dioxide pressure on supercritical extraction of Salvia officinalis L. was investigated. Supercritical fluid extraction with carbon dioxide was done for pressures of 80, 100, 150, 200 and 300 bar. It was concluded that with increasing pressure from 80 to 300 the bar extraction yield enhanced. GC/MS and GC/FID methods were used for qualitative and quantitative analyses of obtained extracts and essential oils from extracts.

Contemporary Materials, 2019

The consequence of drastic reduction in fossil fuel reserves has forced the scientific community ... more The consequence of drastic reduction in fossil fuel reserves has forced the scientific community to find and develop new ways to exploit renewable resources and optimize the process of polymer materials production. The aim is to obtain applicable polymer whose complete life cycle is set in ecological framework. Poly(lactide) (PLA) meets these requirements as biodegradable polyester whose monomer is derived from the plant feedstock containing carbohydrates. PLA could be prepared using the different synthesis routes, but from the point of energy saving, as well as environmental protection, the microwave synthesis of PLA is the best solution. In this work, poly(L-lactide) were synthesized in microwave reactor. Reaction time was varied, while the other parameters of the synthesis were constant. The structures of obtained polymers were confirmed by Fourier – transform infrared spectroscopy (FT-IR). For determination of molar masses of poly(L-lactide) samples, the gel permeation chromatog...

Phenol is a major pollutant in the wastewater because of its presence in the effluent of major pr... more Phenol is a major pollutant in the wastewater because of its presence in the effluent of major processing and refining plants. It has severe effect on human being, both short term and long term. Various methods are used for removal of the phenol from wastewater such as adsorption, photodecomposition, volatilization and other various biological and non-biological methods. In the present study attempt is done to present the survey of the research on the phenol removal by various methods. The methods such as polymerization, electrocoagulation, extraction, photodecomposition, advanced oxidation and ion exchange were used effectively by various investigators. These methods are reported to be efficient for the phenol removal. Suitable method for phenol removal can be selected based on availability of the material, extent of separation required and properties of phenolic effluent.Fenol je jedan od glavnih polutanata u otpadnoj industrijskoj vodi. Utiče na zdravlje ljidi i taj uticaj se isp...

Cilj ovog rada je ukazivanje na mogućnost primene superkritične ekstrakcije sa ugljendioksidom na... more Cilj ovog rada je ukazivanje na mogućnost primene superkritične ekstrakcije sa ugljendioksidom na dekontaminaciju zemljišta zagađenih pesticidima (u ovom slučaju atrazinom). Analizirani rezultati ukazuju da se ova metoda veoma uspešno može koristiti za ostvarivanje istaknutog cilja.The aim of this paper is to study the applicability of supercritical extraction with carbon dioxide to the decontamination of soils containing pesticides (in this case with atrazine). The analyzed results indicate that this method can be successfully used for the realization of prominent purpose

Polylactide belongs to the biodegradable and biocompatible polymers, and degrade to harmless comp... more Polylactide belongs to the biodegradable and biocompatible polymers, and degrade to harmless component, lactic acid, which allows their use in various areas. The development of new methods for the synthesis of polylactide can further extend the application of this polymer and makes its use more economical. The use of microwaves in the synthesis of the polymer can reduce the polymerization time of only 10 to 30 minutes and save a large amount of energy. In this paper, polylactide is synthesized in a microwave reactor, using a frequency of 2,45 GHz and a power of 150 W. FITR analysis confirmed the structure of the resulting polylactide and the thermal properties were studied using differential scanning calorimetry.Polilaktid spada u grupu biorazgradivih i biokompatibilnih polimera i može se razložiti na neškodljivu komponentu, mlečnu kiselinu, što omogućava njegovu primenu u najrazličitijim oblastima. Razvoj novih metoda sinteze polilaktida može proširiti područje primene ovog polimer...

Introduction White spots caused by dental caries are inchoative lesions. They have whitish color,... more Introduction White spots caused by dental caries are inchoative lesions. They have whitish color, opacus aspect and represent an increase of enamel porosity. The treatment of this lesions consist on eliminate the white spot lesion and the remineralization of the enamel surface. Objective The purpose of this study was to compare clinicaly the efficaciousness of the varnish fluoride technique and the microabrasion technique; in order to find the most efficacious, cheapest and easiest application technique. Method For this study 162 young permanent anterior-superior and anterior-inferior dental pieces diagnosed with white spot lesions in the vestibular surface (caused by dental caries) were selected. The sample was distributed in two groups: 81 dental pieces treated with varnish fluoride technique (NaF 5%) and 81 dental pieces treated with microabrasion technique. The two techniques were applicated once a week by a month. After one week of treatment, results were evaluated. Results The microabrasion technique produced greater elimination of white spot lesions (51 dental pieces), white spot lesions of 22 dental pieces were eliminated partialy and 8 dental pieces not eliminated the white spot lesions. Varnish fluoride technique eliminated white spot lesions in 23 dental pieces. The recovery of enamel brightness was the same for the two techniques. Conclusions: The microabrasion technique was more efficaciousness than the varnish fluoride technique; producing a greater recovery of the esthetic aspect, greater remineralization, lower cost, but with a longer time of the application technique. Key words White spot lesions, enamel, microabrasion, varnish fluoride, remineralizationTesisEl esmalte dentario es liso, duro y brillante; pero a veces este es afectado por diversos agentes exógenos y endógenos produciendo diversos cambios de coloración sobre el esmalte dentario. Entre este tipo de coloración tenemos a las manchas blancas. Las manchas blancas causadas por caries dental son lesiones incipientes de caries, de color blanquecino, de aspecto opaco y representa un aumento de la porosidad del esmalte dental. Estas son originadas por procesos continuos de desmineralización. Cuando se encuentran localizadas en el sector anterior producen un efecto antiestético. El tratamiento de estas lesiones la eliminación de la mancha blanca y la remineralización de la superficie dentaria. Estas son realizadas la primera con la finalidad de eliminar el aspecto anti-estético que es la preocupación actual de todos los pacientes y a su vez promover la remineralización para evitar el avance de la lesión. El objetivo de este estudio es comparar clínicamente la eficacia de la técnica de flúor en barniz y la técnica de microabrasión con la finalidad de encontrar la técnica más eficaz en el tratamiento de las manchas blancas. Además de4 encontrar la técnica más económica y de fácil aplicación. Para el presenta trabajo de investigación se seleccionó 162 piezas dentales permanentes jóvenes anterosuperiores y anteroinferiores que presentaban diagnóstico clínico de lesión de mancha blanca en cara vestibular, producida por caries dental. La muestra fue distribuida aleatoriamente en 2 grupos: 81 piezas dentarias tratadas con la técnica de flúor en barniz (NaF al 5%) y 81 piezas dentarias con la técnica de microabrasión (H3PO4 al 37% + piedra pómez + flúor en gel ). Las técnicas fueron aplicadas semanalmente por el lapso de un mes. Luego de una semana se observaron los resultados. Posteriormente de obtener los resultados, se encontró que la técnica de microabrasión producía unas mayor eliminación de las manchas (51 piezas dentarias), mientas que la técnica de flúor en barniz no producía casi eliminación de la mancha (33 piezas dentales). En cuanto a la recuperación del brillo (remineralización) se observó que ambas técnicas eran eficaces y producían cantidades iguales de remineralización. Con los siguientes resultados se concluyó que la técnica de microabrasión (H3PO4 al 37% + piedra pómez + flúor en gel) era más eficaz que la técnica de flúor en barniz (Na F al 5%); recuperándose el aspecto estético de las superficies dentarias, alta remineralización, bajo costo pero requiere mayor tiempo operatorio

TesisLima NorteEscuela de PosgradoGestión de los Servicios de la SaludEn el trabajo asistencial, ... more TesisLima NorteEscuela de PosgradoGestión de los Servicios de la SaludEn el trabajo asistencial, los odontólogos se encuentran expuestos ante una variedad de microorganismos que ocasionan enfermedades. El uso de instrumentos cortantes y el contacto con fluidos orgánicos contaminados conllevan, un riesgo de transmisión de infecciones al personal clínico y al paciente. Ante esta problemática se crearon las normas de bioseguridad en Odontología establecidas por organismos nacionales e internacionales y deben ser seguidas a plenitud. El objetivo del estudio es evaluar la percepción del cumplimiento de la norma de Bioseguridad en enfermedades transmisibles durante la práctica clínica Odontológica en profesionales que pertenecen a sociedades científicas odontológicas encargadas de regular y vigilar las normas legales establecidas por el sistema de Salud. Se evaluó las dimensiones: medidas básicas de prevención, uso de barreras, manejo de residuos contaminados y enfermedades transmisibles. Es un estudio descriptivo, transversal, cuantitativo que mostró como resultados que la población estudiada tiene un nivel regular de percepción del cumplimiento de las normas a pesar de existir normas reguladoras de la bioseguridad en Odontología. La población demostró tener mejor cumplimiento en el manejo de residuos contaminados

Thermo power plant TPP Ugljevik for the production of electricity use brown coal with a high cont... more Thermo power plant TPP Ugljevik for the production of electricity use brown coal with a high content of sulfur (about 5%). As a product of combustion of coal, beside other pollutants, is sulfur dioxide which is dangerous for environment and human health. The concentration of sulfur dioxide in flue gases is about 25000 mg/Nm3. This concentration is 62,5 times higher then permitted concentration (by European Union). The work contain data of sulfur dioxide which TPP Ugljevik are emitted during one year, the data of concentration in air of sulfur dioxide in location of TPP Ugljevik and city Ugljevik. The paper considered influence of emitted sulfur dioxide on environment, materials, cultural heritage and human health. On the other hand paper considered advantageous consequences for environment, materials and human health which will bes after introduction of the process of desulfuration of flue gases in TPP Ugljevik. The process of desulfuration is very important for reduction of trans-b...

Zastita materijala, 2017

Proizvodnja vodonika gasifikacijom biomase IZVOD Vodonik bi u narednom periodu mogao postati znač... more Proizvodnja vodonika gasifikacijom biomase IZVOD Vodonik bi u narednom periodu mogao postati značajan izvor energije jer su njegova proizvodnja, transport i skladištenje uglavnom riješeni. U ovom radu se daje pregled proizvodnje vodonika iz lignoceluloznih obnovljivih izvora. Proces je obrađen u svim njegovim fazama i alternativnim rješenjima. Tako su obrađene dva različita, alternativna, procesa gasifikacije biomasedirektna i indirektna i dva različita, alternativna, reforming modelaparcijalna oksidacija i reformiranje vodenom parom. Prečišćavanje gasa je, takođe, dato sa dvije različite, alternativne, koncepcijehladno i toplo prečišćavanje gasa. Konverzija radnog gasa i razdvajanje vodonika od CO 2 i drugih primjesa se danas radi u membranskom cijevnom reaktorusve na jednom mjestu što je znatno smanjilo cijenu koštanja 1 kg vodonika. U svim ovim procesima je posebno vođeno računa o integraciji energije u procesu što je takođe znatno doprinijelo ekonomski povoljnijoj cijeni vodonika.

Zastita materijala, 2015

The most promising biofuels are bioethanol, biodiesel, pure plant oil, and biomethane. Many biofu... more The most promising biofuels are bioethanol, biodiesel, pure plant oil, and biomethane. Many biofuels generate large benefits when compared to fossil fuels. The use of bioethanol will largely depend on the potential of available and continuously re-growing biomass, the feedstock sources. Bioethanol produced from renewable feedstock has great potential to reduce greenhouse gasses emissions related to the combustion of fossil fuels. It has chemical and physical properties that are close to fuels from fossil fuels and can be used to exchange petrol in existing engines. Generally bioethanol is expected to have large socioeconomic impacts, especially for local actors. Bioethanol production opens new market opportunities for agricultural products and thus new income options for farmers. In the future agriculture will not only play a role in food production, but also in energy provision.

Applied Technologies and Innovations, 2010

The aim of this paper is to define feasible process pathways of fractional crystallization of NaC... more The aim of this paper is to define feasible process pathways of fractional crystallization of NaCl and LiClO43H₂0 from LiClO₄-NaCl-H₂O system using the information on the equilibrium of the LiClO₄-NaCl-H₂O system at different temperatures, as well as the information on the composition of the starting solution obtained by electrolysis and double exchange with LiCl. The paper also synthesizes a feasible process structure that can be applied for the process of fractional crystallization, and gives a simulation of the process by calculating the material balance of the process. The parameters of relevant process paths that were obtained prove that the process presented in this paper is feasible in practice and applicable in industry.

Hemijska industrija, 2002

A mathematical model of the desorption process based on the synthesised technological topology of... more A mathematical model of the desorption process based on the synthesised technological topology of the regeneration process gas components NH3 and CO2, was developed. The logical principle methodology of the mathematical modelling of desorption processes was worked out in detail. The mathematical model of the process, including the following: - The synthesized technological scheme of the desorption of components NH3 and CO2, with all the necessary requirements and limitations of the mathematical model; - The relevant multicomponent systems which exist in the process were defined in which the interphase transformation occurs; - The considered units (aparatus) are defined which make up the basic technological topology of the process; - Desorption processes in towers with different types of trays were defined and mathematically described; - The cooling process and condensation of gas phase in a complex multicomponent system was of the gas phase in a complex multicomponent system was def...

Izvod Polazeći od eksperimentalnog dijagrama koncentracija-vreme (c A ,t), u radu je grafičkom me... more Izvod Polazeći od eksperimentalnog dijagrama koncentracija-vreme (c A ,t), u radu je grafičkom metodom konstruisan dijagram brzina reakcije-vreme (r A ,t). Konstrukcija je izvedena na bazi konstruisanih tangenti u proizvoljnim tačkama polaznog dijagrama i povlačenjem potega paralelnih sa istim u unapred zadatom polu. Dokaz konstrukcije izveden je primenom diferencijalne geometrije odnosno glavne teoreme diferencijalnog računa. Pri ovome iskorišćene su diferencijalne osobine između posmatranih veličina. Iz analitičkih zavisnosti r A = = r A (t) i c A = c A (t) koje mogu biti vrlo složene (polinomi n-tog stepena), eliminisanjem vremena t radi potpunijeg opisivanja procesa, može se dobiti analitička zavisnost r A = r A (c A) koja se zatim grafički predstavlja. Međutim, ovo eliminisanje vremena, može se izvršiti i grafički, na relativno jednostavan način. Nakon toga, primenom integralnog računa pokazano je da je priraštaj koncentracije u vremenskom razmaku srazmeran površini dijagrama (r A ,t). Primenom slične procedure, u nastavku, pokazano je da je priraštaj vremena srazmeran površini dijagrama (1/r A ,c A). Da bi prikazana metoda imala praktičnu primenljivost, u radu su izvedene relacije za odgovarajuće koeficijente razmere. Verifikacija metode prikazana je na dva karakteristična primera iz hemijske kinetike, pri različitoj monotonosti polaznih eksperimentalnih funkcija.

Predmet rada se odnosi na projektovanje pouzdanosti kod procesa polimerizacije koji se odvijaju u... more Predmet rada se odnosi na projektovanje pouzdanosti kod procesa polimerizacije koji se odvijaju u reaktorima jedne hemijske industrije. Kroz razvijeni model, određene su karakteristike i pokazatelji pouzdanosti, a time i utvrđeni osnovni faktora koji doprinose lošem odvijanju procesa. S obzirom na mogućnost njihove kontrole, mogu se smanjiti očekivani gubici, i na taj način postići kvalitetnija proizvodnja. Za analizu i proračun pouzdanosti, primenjena je deduktivna metoda zasnovana na konstruisanju šeme stabla otkaza sistema na bazi induktivnog zaključivanja. Pri ovome korišćeni su standardizovani logički simboli, odnosno pravila Bulove algebre i matematičke logike. Rezultati rada kroz kvantitativnu i kvalitativnu analizu pouzdanosti posmatranog procesa, omogućavaju dobijanje potpunih informacija o verovatnoći neželjenog događaja procesa i donošenje objektivnih odluka i alternativnih rešenja.

Hemijska industrija, 2010

In this paper, a computer aided analysis and synthesis of the crystallization processes from mult... more In this paper, a computer aided analysis and synthesis of the crystallization processes from multicomponent electrolyte systems were studied. In addition, the vacuum crystallization processes with adiabatic cooling of the system are presented. The cooling process of a multicomponent electrolyte system can be considered as a process with the concentration of the system and/or the crystallization of the solid phase from the system. Requirements for multivariant options of the process simulator are the result of practical needs in the design of new processes or the improvement of exploitation processes. According to this, there are needs for a simulation of a simple flashing of the system as well as for the vacuum cooling crystallization processes with the cyclic structure. The possibilities of the created process simulator are illustrated on three component electrolyte systems. Application of the process simulator for any other electrolyte systems requires only an update of the thermo...

Journal of the Serbian Chemical Society, 2011

This paper presents an attempt to define the non-linear correlation dependence between the degree... more This paper presents an attempt to define the non-linear correlation dependence between the degree of decomposition of the aluminate solution, the average diameter of the crystallized gibbsite, the total Na2O content in the obtained alumina and the specific utilization level of the process on the one hand and important input parameters of the process on the other. As input parameters having an influence on the process, the concentration of Na2O (caustic), the caustic ratio and the crystallization ratio, the starting and final temperature of the process, the average diameter of the crystallization seed and the duration of the decomposition process were considered. As the result of measurements of these process parameters and the acquisition of the resulting output parameters of the process, a database with 500 data lines was obtained. To define the correlation dependence, with the aim of predicting the process parameters of the decomposition process of the sodium aluminate solution, t...