Upravljački aspekti implementacije međunarodnog standarda upravljanja okolinom ISO 14001:2004

This paper analyzes the managerial aspect in the implementation of international environmental management standard ISO 14001:2004. It is known that the implementation of this standard has all the elements of the project approach, which is the responsibility of the management of organizations (companies, institutions, etc.) is crucial. This aspect is analyzed for its impact on all other elements in the management of the environment, directly on the determination of the needs for the introduction of environmental management systems, formulation of environmental policy, planning activities, implementation plan, measure results, evaluation of results achieved, and continuous improvement. The concept of EMS (Environment Management System) is based on the introduction of a systematic and logical conditional process of environmental management in the way that affects the organization, control and prevent adverse environmental impacts that are reflected through the work of the same, and the role of the organization management and managerial approach is reflecting to the essence and form of implementation of international standards

Influence of process conditions on reduction of silicon and calcium impurities in aluminum solution

As it is known, during regular conditions Bayer\u27s process is used for production of alumina of a 99.0 % grade of purity. In order to obtain high-purity alumina which can then be used for special purposes, additional purification is performed in relation to the application of impurities, and, in the first hand removal of silica (Si) and calcium (Ca). One of the most effective ways of removing these compounds is the process of desilication. The method consists of treating an aluminate solution with lime that binds silica and calcium to tricalcium-aluminate (TCA) which is insoluble and therefore easily separated of the solution. The experimental research examined the impact of process parameters (temperature, time, concentration of added lime) on the efficacy of purifying aluminate solution from Si and Ca, which has a practical and theoretical contribution to aluminate solution research. Synthetic aluminate from non-metallurgic alumina and pure sodium-alkaline (NaOH) is used, in the caustic ratio in the range of 1.45-1.55. Classic volume analysis and analysis using optical emigration spectroscopy (ICP-OES) were used to determine the contents of aluminum and impurities.&nbsp;The experimental research found that short intervals are adverse because soluted compounds Ca(OH)2 and tetra-calcium aluminum are formed. Also, during longer reaction time and higher temperatures there was an increase in the contents of Si and Ca in the aluminum, because some components from the limestone were dissolved. Small amounts of lime are adverse because there is an increase in calcium content in the solution since part of the lime dissolved, without interacting with the present impurities, while large quantities led to large aluminum loss due to the formation of TCA.</p

O jednoj pogodnoj metodi za optimizaciju zavarenog sklopa

The paper shows an example of performed optimization of sizes in terms of welding costs in a characteristic loaded welded joint. Hence, in the first stage, the variables and constant parameters are defined, and mathematical shape of the optimization function is determined. The following stage of the procedure defines and places the most important constraint functions that limit the design of structures, that the technologist and the designer should take into account. Subsequently, a mathematical optimization model of the problem is derived, that is efficiently solved by a proposed method of geometric programming. Further, a mathematically based thorough optimization algorithm is developed of the proposed method, with a main set of equations defining the problem that are valid under certain conditions. Thus, the primary task of optimization is reduced to the dual task through a corresponding function, which is easier to solve than the primary task of the optimized objective function. The main reason for this is a derived set of linear equations. Apparently, a correlation is used between the optimal primary vector that minimizes the objective function and the dual vector that maximizes the dual function. The method is illustrated on a computational practical example with a different number of constraint functions. It is shown that for the case of a lower level of complexity, a solution is reached through an appropriate maximization of the dual function by mathematical analysis and differential calculus.U radu je, na primeru jednog karakterističnog opterećenog zavarenog sklopa, izvršena optimizacije njegovih dimenzija sa aspekta troškova zavarivanja. Pri ovome, u prvoj fazi definisane su promenljive i nepromenljive veličine i postavljen matematički oblik funkcije optimizacije. U sledećoj etapi procedure, definisan je i postavljen sistem najvažnijih funkcija ograničenja koji se pri projektovanju konstrukcije moraju uzeti u obzir i tehnolog i konstruktor. Na taj način, dobijen je matematički model optimizacije posmatranog problema za čije je efikasno rešavanje predložen metod geometrijskog programiranja. U nastavku, polazeći od matematičke osnove, detaljno je razrađen algoritam optimizacije predložene metode pri čemu su postavljene glavne jednačine problema, a koje važe uz određene uslove. Na taj način, optimizacioni ili primarni zadatak sveo se na dualni zadatak preko odgovarajuće funkcije, koji se znatno lakše rešava u odnosu na primarni zadatak optimizacije funkcije cilja. Glavni razlog za ovo je dobijeni sistem linearnih jednačina. Pri ovome iskorištena je korelacija između optimalnog primarnog vektora koji minimizira funkciju cilja i dualnog vektora koji maksimizira dualnu funkciju. Metoda je ilustrovana na jednom računskom praktičnom primeru sa različitim brojem funkcija ograničenja. Pokazano je da se za slučaj manjeg stepena složenosti, do rešenja može doći maksimizacijom odgovarajuće dualne funkcije, primenom matematičke analize odnosno diferencijalnog računa

Analitička greška kod izbora referentnog stanja u termodinamici idealnog gasa

The paper is based on the fact that the internal energy, enthalpy and enthropy as most important thermodynamic state functions, can not be determined in absolut terms without reference state slections. It is demonstrated that to determination must be approached very cautiously. The reason for this is possibility of errors that are not permissible. The beginning conditions of measurement can be adopted. It is also necessary to pay attention to the beginning the measurement of the adopted reference value. For a case to be simultaneous determination of multiple state functions, it should take to account the beginning of the measurement of each of these functions, since this start may different. In this way the calculated state function vares, depending on refenece state is adopted. At the end, in one convenient example, in the case internal energy and enthalpy, as a characteristic state function, is pointed to possiility errors, which could occur if there is no detailed analysis of adopted reference of „zero“ state.U radu je, polazeći od činjenice da se unutrašnja energija, entalpija i entropija kao najvažnije termodinamičke veličine stanja, ne mogu odrediti u apsolutnom iznosu bez izbora referentnog stanja, pokazano da je pri ovom određivanju potrebno pristupiti veoma obazrivo. Razlog za ovo je mogućnost grešaka koje nisu dopustive. Pri ovome usvojeni početak merenja može u opštem slučaju biti različit. Neophodno je takođe obratiti pažnju na definisanost određene veličine stanja za usvojenu referentnu vrednost. Za slučaj da se vrši istovremeno određivanje više veličina stanja, treba voditi računa o početku merenja svake od ovih veličina, s obzirom da ovaj početak može biti različit. Na ovaj način izračunata veličina stanja zavisi od toga koje referentno stanje je usvojeno. Na kraju rada, koristeći praktičan računski primeru, za slučaj unutrašnje energije i entalpije, kao karakterističnih veličina stanja, ukazano je na mogućnost greške, koja se može javiti ukoliko se ne izvrši detaljna analiza izbora referentnog, odnosno „nultog“ stanja.XI Conference of Chemists, Technologists and Environmentalists of Republic of Srpska, Teslić / Xi savjetovanje hemičara, tehnologa I ekologa Republike Srpske, 14.07.2016

Graphical determination of polytropic index in characteristic diagrams

U ovom radu, koristeći postojeća znanja iz termodinamike, prikazana su tri načina grafičkog određivanja eksponenta politrope, kao i klasični analitički način.U radu smo koristili karakteristične dijagrame p-v i T-s i u njima konstruisali određene politropske promene koje smo u daljim razmatranjima koristili za određivanja eksponenta politrope. Prvi način se zasniva na konstruisanju dijagrama log p=f(log v) i iz nagiba prave očitavamo vrednost traženog eksponenta. Druginačin je nešto složeniji i zasniva se na konstruisanju politrope u p-v dijagramu, na koju, u proizvoljnoj tački politrope, povlačimo tangentu i diferencijalnom metodom dolazimo do eksponenta politrope. A treći način zasniva se na konstruisanju politrope u T-s dijagramu, korišćenju osnovnih teorema diferencijalnog računa, odnosno I i II zakona termodinamike za uočene izotermske promene i pisanju osnovne jednačine politropske zavisnosti u diferencijalnom obliku. Prikazana grafička rešenja omogućuju efikasnijije teorijsko izučavanje politropskih promena stanja i znatno pomažu jasnijiem sagledavanju problema koji su u vezi sa ovom vrstom promene stanja

Jedna mogućnost grafičkog predstavljanja energetskih veličina realnog gasa za karakterističnu promenu stanja

In this paper, for the case of isothermal quasi static characteristic change of the state of real gas is given graphical representation respectively determination of the most important energy values in h-s and T-s diagrams. At present, by using the fundamental theorem of differential calculus, the first and second law of thermodynamics is written in differential form, dependence is derived that allowed precise graphic design to determine the most important values of the process (technical work and amount of exchanged heat) to h-s diagram, over certain straight lines which represent the height differences. Performed graphic design, is applied to two typical cases in the same diagram. Also, a comparison is performed with same change of state in the case of an ideal gas. In the second part of this paper, starting from the fact that for the behavior of real gas, co-ordinate systems h, s and T, s are suitable but p, v systems, the proposal is given to the graphic representation of the changes of enthalpy and internal energy in heat T-s diagram. In this case, it is used the lines of constant enthalpy and internal energy i. e. that is their point of intersection with isobars, which passing through the endpoint of analyzed the change of state. It is shown that the change of enthalpy and internal energy in T-s diagram can be presented planimetry over the appropriate areas. Based on the certain change of enthalpy and internal energy, by using the both form of the first law in thermodynamic, it is shown that in addition to the amount of ex- changed heat, but it is possible for volume and technical work, for the proposed change of state of real gas, also can be represented graphically in T-s diagram, over suitable equivalent areas, which was the basic idea of this paper. Displayed graphics solutions in relation to the analytical solutions allows more efficient theoretical study of thermodynamic process which is observed from different points, they significantly assist for clear understanding of the problem and improve of mutual understanding.U radu je za karakterističnu kvazistatičku izotermsku promenu stanja realnog gasa, dato grafičko predstavljanje odnosno određivanje najvažnijih energetskih veličina u h-s i T-s dijagramima. Koristeći osnovnu teoremu diferencijalnog računa, odnosno I i II zakon termodinamike napisan u diferencijalnom obliku, izvedena je opšta zavisnost koja je omogućila preciznu grafičku konstrukciju za određivanje najvažnijih veličina procesa (tehnički rad i razmjenjena količina toplote) u h-s dijagramu, preko odgovarajućih duži koje predstavljaju visinske razlike. Izvedena grafička konstrukcija, primjenjena je na dva karakteristična slučaja u istom dijagramu. Prethodno je izvršeno i poređenje sa istom promenom stanja za slučaj idealnog gasa. U drugom delu rada, polazeći od činjenice da su za prikazivanje promena stanja realnog gasa mnogo pogodniji koordinatni sistemi h, s i T, s nego p, v sistem, dat je predlog za grafičko predstavljanje promene entalpije i unutrašnje energije u toplotnom T-s dijagramu. Iskorištene su linije konstantne entalpije i unutrašnje energije, odnosno njihove presečne tačke sa izobarom i izohorom, koje prolaze kroz krajnju tačku analizirane promjene stanja. Pokazano je da se promena entalpije i unutrašnje energije u T-s dijagramu može predstaviti planimetrijski preko odgovarajućih površina. Na bazi određene promene entalpije i unutrašnje energije, koristeći oba karakteristična oblika i zakona termodinamike, pokazano je da je pored razmenjene količine toplote, moguće i zapreminski i tehnički rad, za usvojenu promenu stanja realnog gasa, takođe grafički predstaviti u T-s dijagramu preko odgovarajućih ekvivalentnih površina, što je bila i osnovna ideja rada. Prikazana grafička rešenja u odnosu na analitička, omogućuju efikasnije teorijsko izučavanje i predstavljanje posmatranog termodinamičkog procesa sa različitih aspekata, i znatno pomažu jasnijem sagledavanju problema i poboljšanju međusobnog sporazumevanja

New model for determining of change entropy of semi-ideal gas by using fractional temperature function

Kod poluidealnog gasa, promena entropije ne može se odrediti preko srednjeg specifičnog toplotnog kapaciteta na način kao što se određuje promena unutrašnje energije i entalpije, odnosno razmenjena količina toplote. Uzimajući ovo u obzir, u radu je izveden pogodan model preko koga je moguće odrediti promenu specifične entropije poluidealnog gasa za proizvoljan temperaturski interval primenom tablične metode, koristeći srednje vrednosti razlomljenih temperaturnih funkcija. Ideja je da se integriranje koje se ovde neminovno javlja, zameni srednjim vrednostima prethodnih funkcija. Model je izveden na bazi funkcionalne zavisnosti stvarnog specifičnog toplotnog kapaciteta od temperature. Pri ovome korišćena je teorema o srednjoj vrednosti funkcije kao i matematičke osobine određenog integrala. Srednja vrednost razlomljene funkcije određena je direktno preko njene podintegralne funkcije. Izvedene relacije, primenom računarskog programa, omogućile su sastavljanje odgovarajućih termodinamičkih tablica preko kojih je moguće odrediti promenu entropije proizvoljne promene stanja na efikasan odnosno racionalan način bez primene integralnog računa, odnosno gotovih obrazaca. Na ovaj način, promena entropije poluidealnog gasa, određena je za proizvoljan temperaturski interval analognom metodom koja se primenjuje i kod određivanja promene unutrašnje energije i entalpije odnosno razmenjene količine toplote, što je bio i cilj rada. Verifikacija predložene metode za gore navedenu funkciju, izvedena je za određeni poluidealni gas za tri usvojena temperaturska intervala, za karakterističnu promenu stanja. Pri ovome izvršeno je poređenje rezultata prema klasičnoj integralnoj i predloženoj metodi preko sastavljenih tablica.Prikazanu metodu, u određenim odnosno posebnim slučajevima, moguće je primeniti i kod određivanja promene entropije realnog gasa.Isto tako, u radu je pokazano da je promenu entropije za posmatrani karakterističan slučaj, moguće predstaviti odnosno grafički odrediti planimetrijskom metodom u dijagramima sa pogodno odabranim koordinatama

Solving some problems in field of heat capacity by using of new correlation

In the thermodynamics practice, both for semi – ideal and for real gases, the dependence of the middle specific heat capacity of temperature, is usually determined by experimentally as linear function, mainly, for the relatively short temperature range. In addition to this, for the purpose of various analyzes, both in theory and in practice, is necessary to know the dependence of the real specific heat capacity of temperature also. Due to this, in this paper was the definition of the middle specific heat capacity for certain, selected a suitable temperature range, by using differential and integral calculus, analytical dependence is derived from the real specific heat capacity and the middle specific heat capacity. The relation which is given in the differential form for defined temperature range, allows direct troubleshooting without special restriction on its use. By using the resulting dependence, the general model is derived in the form of polynomial of arbitrary degree by depending of temperature, which is faster and more convenient for practical application of the current model, which has not a general character. Also the existing model is not the most appropriate because it solves the problem given indirectly, considering it requires analytical dependence of the amount of exchanged heat. Correlation which has derived in this paper, can be effectively applied to obtain of depending on the amount of exchanged heat between the temperature and also for the observed temperature range. Derived analytical relation was used to obtain another relation to the amount of exchanged heat which have a more complex form of the existing two, which can be applied for various thermodynamic analysis. Verification of the present model and the possibility of its application is given to a few characteristic examples of semi – ideal and real gas and CO2 gas as semi – ideal based on the experimental results, the diatomic semi ‒ ideal gases starting from Einstein relation, water as real fluid starting from the Dieteritium relation, and at the and characteristic group of real gases. Therefore, it is seen wider temperature range

Grafičko predstavljanje energetskih veličina idealnog gasa u karakterističnim dijagramima na način koji nije uobičajen

In this paper, for characteristic polytropic change of state of ideal gas is given graphical planimetric graphical representation of the most important energy values in workplace and thermal diagram, trough the appropriate area. In this paper, we used differential forms of the First and Second law of thermodynamics and basic equation which define the observed change of state, written in a suitable form. The results for the polytropic change of state, are applied to the isobaric and isochoric change of state. It is shown that any of the energy values ( q12, w12, wt12, Dh12, Du12) can be present in both workplace (p, v) as well as thermal (T-s) diagram. Graphical solutions, compared to the analytical, provide efficient theoretical explain and presentation of various thermodynamic processes of ideal gas with different aspects and greatly assist a clearer view of the problem and enhance each other living arrangement. Graphical representation of external influences or energy values shown in the diagrams, make it possible to more clearly we see connection between these effects, change of state, as well as their each other relations. This is particularly evident in the case when there are (p, v) and (T-s) diagram for a par tic u lar ideal gas, which is common in technical practices (e. g., air as an ideal gas).U radu je za karakterističnu politropsku promenu stanja idealnog gasa dato grafičko planimetrijsko predstavljanje najvažnijih energetskih veličina u radnom i toplotnom dijagramu, preko odgovarajućih površina. Pri ovome korišćeni su diferencijalni oblici prvog i drugog zakona termodinamike, kao i osnovne relacije koje definišu posmatranu promenu stanja, napisane u pogodnom obliku. Dobijeni rezultati, za politropsku kao opštu promenu stanja, primenjeni su na izobarsku i izohorsku, kao karakteristične promene stanja. Pokazano je da bilo koju od energetskih veličina (q12, w12, wt12, Δh12, Δu12) moguće predstaviti kako u radnom (p-v), tako i u toplotnom (T-s) dijagramu. Prikazana grafička rešenja, u odnosu na analitička, omogućuju efikasnije teorijsko razmatranje i predstavljanje različitih termodinamičkih procesa idealnog gasa sa različitih aspekata i znatno pomažu jasnijem sagledavanju problema i poboljšavaju međusobno sporazumevanje. Grafički prikazi spoljnih uticaja, odnosno energetskih veličina u prikazanim dijagramima, omogućuju da se još jasnije uoči veza između tih uticaja, promena stanja, kao i njihovi međusobni odnosi. Ovo posebno dolazi do izražaja za slučaj kada postoji (p, v) i (T-s) dijagram za određeni idealni gas, što je čest slučaj u tehničkoj praksi (na primer za vazduh kao idealan gas)

Predlog za određivanje minimalne zapremine rezervoara za karakteristične komprimovane gasove na bazi koncepta maksimalnog rada

Starting from the main relation for closed thermodynamic systems for maximum work of reverse processes, a general model for determining the minimum volume of the tank containing compressed ideal gases, nitrogen and oxygen, as the main constituent components of the air has been developed. In addition to thermal and mechanical, in the observed complex system there is a concentration imbalance. In this way, the analyzed isolated system fulfills the conditions for obtaining work. In determining the model, it is assumed that the initial parameters of the gas in the tank, the state of the environment and the necessary energy (maximum work) to be obtained from the given gas are known. Thermal and mechanical imbalance is realized through an isentropic and isothermal state change, while the problem of concentration imbalance, considering the observed gases, is solved on the basis of the relation for the volume fraction of the component in the gas mixture, i.e. the partial pressure of the observed gas in the environment. In addition to the analytical, in order to control the obtained results, a graphical solution of the observed problem was given using the p-v i.e. T-s diagram. At the end of the work, the application of the model is illustrated on a practical example from practice, where the minimum volumes of the tank for nitrogen and oxygen as characteristic gases, were defined. In order to compare the results, the volume of the tank in which the air is located is determined under the same initial conditions, i.e. the same parameters of the environment. The obtained results can be used in practice for dimensioning or estimating the actual volume of the reservoirs for technical gases, since the actual processes are generally irreversible from the thermodynamic aspect.Polazeći od glavne relacije za zatvorene termodinamičke sisteme za maksimalan rad povratnih procesa, u radu je izveden opšti model za određivanje minimalne zapremine rezervoara u kome se nalaze komprimovani idealni gasovi azot i kiseonik koji su glavne sastavne komponente vazduha. Pored termičke i mehaničke neravnoteže, u posmatranom kompleksnom sistemu postoji i koncentraciona neravnoteža. Na taj način u analiziranom izolovanom sistemu su ispunjeni uslovi za dobijanje rada. Pri određivanju modela, pošlo se od pretpostavke da su poznati početni parametri gasa u rezervoaru, stanje okoline kao i neophodna energija (maksimalni rad) koji treba dobiti od datog gasa. Termička i mehanička neravnoteža ostvarena je preko izentropske i izotermske promene stanja dok je problem koncentracione neravnoteže, s obzirom na posmatrane gasove, rešen na bazi relacije za zapreminski udeo komponente u mešavini gasova odnosno parcijalni pritisak posmatranog gasa u okolini. Pored analitičkog rešenja, radi kontrole dobijenih rezultata dato je i grafičko rešenje posmatranog problema korišćenjem p-v odnosno T-s dijagrama. Na kraju rada primena modela ilustrovana je na jednom primeru iz prakse gde su određene minimalne zapremine rezervoara za azot i kiseonik, kao posmatrane karakteristične gasove. Radi poređenja rezultata određena je i zapremina rezervoara u kome se nalazi vazduh pod istim početnim uslovima odnosno istim parametrima okoline. Dobijeni rezultati u praksi mogu poslužiti za dimenzionisanje odnosno procenu stvarne zapremine rezervoara za tehničke gasove s obzirom da su stvarni procesi sa termodinamičkog aspekta uglavnom nepovratni