Submicron and nanosized powders have gained significant attention in recent decades due to their broad applicability in various fields. This work focuses on ultrasonic spray pyrolysis, an efficient and flexible method that employs an aerosol process to synthesize titanium-based nanoparticles by transforming titanium oxy-sulfate. Various parameters are monitored to better optimize the process and obtain better results. Taking that into account, the influence of temperature on the transformation of titanium oxy-sulfate was monitored between 700 and 1000 °C. In addition to the temperature, the concentration of the starting solution was also changed, and the flow of hydrogen and argon was studied. The obtained titanium-based powders had spherical morphology with different particle sizes, from nanometer to submicron, depending on the influence of reaction parameters. The control of the oxygen content during synthesis is significant in determining the structure of the final powder.

The influence of process parameters in the three-stage purification of aluminate solution from the Bayer process and aluminum hydroxide was considered in this paper. One of the ways of purification is treating the aluminate solution in order to reduce the concentrations in the starting raw material (solution) and then treating the aluminum hydroxide at a certain temperature and time in order to obtain an alumina precursor of adequate quality. The purification process itself is divided into three phases. The first phase involves the treatment of sodium aluminate with lime in order to primarily remove Ca2+ and (SiO3)2− impurities. Phase II aims to remove impurities of Zn2+, Fe2+, and Cu2+ by treatment with controlled precipitation using specially prepared crystallization centers. In Phase III, Na+ is removed by the process of hydrothermal washing of Al2O3 ∙ 3H2O. In this work, parameters such as temperature (T), reaction time (t), and concentration of lime (c) were studied in order to remove the mentioned impurities and obtain the purest possible product that would be an adequate precursor for special types of alumina.

<p>In this paper, the influence of process parameters on the morphological properties of fine precipitated hydrate was examined. The research was conducted with the aim of synthesizing fine precipitated aluminum hydroxide from the aluminate solution obtained by the Bayer process. Fine precipitated hydrates obtained in this way are mostly used in the non-metallurgical industry. The synthesized fine precipitated hydrate should comply with certain quality requirements such as granulometry (average particle diameter), purity, specific surface area, whiteness, etc. This paper shows the influence of certain technological parameters, namely the initial precipitation temperature, the amount and specific surface area of the seed, the influence of the NaOH/Al(OH)3 molar ratio on the characteristics of the synthesized fine precipitated hydrate in terms of the specific surface area, mean diameter and morphology of the obtained particles.</p>

This paper presents research on hydrodynamics and mass transfer in a packed absorption column. Experimental data on dry column pressure drop, flooding point, and efficiency of absorption of CO2 in water is obtained on a lab-scale absorption column packed with Raschig rings. Auxiliary parts of equipment together with chemical analyses provide simple monitoring and collecting the data. All obtained data were used to test different mathematical models for a given problem, i.e. for determination of the dry column pressure drop, flooding point and the overall gas transfer unit height. For dry column pressure drop, models developed primarily for packed columns described the data the best, with the Billet model generating a 6.54 % mean error, followed by Mackowiak and Stichlmair models. In flooding point calculations, empirical models were tested and models of Lobo, Leva and Takahshi gave the best results. Mass transfer (absorption) experiments gave expected results, since absorption efficiency increased with the increase in the liquid/gas flow rate ratio, i.e. with approaching the flooding point. The Onda?s model was used to calculate partial mass transfer coefficients in liquid and gas phases based on which the height of the overall gas transfer unit was estimated and subsequently compared with the experimental data. Deviation of calculated and experimental results for the height of the overall gas transfer unit is in the expected range of 0-20 %, with mean value of 15.5 %. In conclusion, the available models for determination of the investigated hydrodynamics and mass transfer parameters in packed absorption columns gave adequate results in comparison to the experimental values.

It is known that the temperature of crystallization during the synthesis of zeolite is one of the most important process parameters. However, during the research work on the synthesis of zeolite 13X and the introduction of this material into regular industrial production, it was noticed that the heating rate of the starting reaction suspension can have an equally important influence. This influence can be so pronounced that a difference of just a few minutes in reaching the crystallization temperature can make a significant difference in product quality, affect the presence of other phases in the crystal, or even determine the direction of zeolite crystallization. Therefore, the aim of this work was to show the influence of the heating rate on the quality of the obtained 13X zeolite powders. The obtained samples were analysed in terms of crystallinity (by X-ray diffraction), chemical composition, granulometry and specific surface area (by Brunauer-Emmett-Teller analysis), and regarding water and CO2 adsorption capacities. Additionally, scanning electron microscopy analysis of the samples showed the morphological characteristics of different 13X zeolite powders. The analysis results of the obtained powders confirmed the influence of the heating rate and helped to define the optimal synthesis parameters i.e. the initial temperature and heating time, that resulted in stable product quality.

: As it is known, during regular conditions Bayer's 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. 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.

Development refers to the process of growth and change in order to progress. Integral development of a particular community implies general social, economic and environmental progress. So, the concepts of social and economic development are mostly clear, but the progress and development of the environment involves all the processes and interactions of man and his surroundings and vice versa. Since the local level is the level of everyday existence of an individual, the problems of local development are mainly problems of the individual. For this reason, local governments (municipal and city) have the particular challenge of establishing a model of integrated development management at the local level, since they are vitally interested in local development but are not fully competent and responsible. According to some recommendations within the local government framework, an organizational development management unit should be established. Challenges to an adequate model are reflected in organizational and human resources solutions. Organizational issues arise when this unit is set up at a low hierarchical level because it is an issue of influence or, on the other hand, too high and is subject to certain external influences or even subject to political distribution at the local level. On the other hand, human resources issues are related to the motivation and competencies of key persons in the organizational development management unit and thus their influence on certain development processes at the local level.

Polazeći od I i II zakona termodinamike, primjenjenog upovratnim procesima, a kod kojih je postignuta ravnoteža pritiskai temperature, u radu je izveden izraz za ukupni maksimalnizaprmenski rad zatvorenih sistema. Radi potpunije interpretacijeove problematike za dva karakteristična slučaja, dat je grafičkiprikaz u p-v dijagramu, gdje se na očigledan način zapaža da senajveći rad širenja sastoji iz izenropskog i izotermnog rada kao irada protiv pritiska okoline. Na bazi izvedenog izraza, koristećiodgovarajuće termodinamičke relacije, izveden je izraz zaspecifični maksimalni rad koji je pogodan za analizu. Dobijeni izrazje posmatran kao dvodimenzioni problem odnosno kao funkcijadvije promijenive: početni pritisak i početna temperatura kaoprimarni parametri. Primjenom matematičke analize dokazano jepostojanje minimuma posmatrane funkcije, i dato njeno grafičkopredstavljanje u prostornom koordinatnom sistemu. Detaljnommatematičkom analizom pokazano je da u opštem slučaju funkcijamaksimalnog rada geometrijski predstavlja jednu konkavnupovršinu u prostoru.Radi efikasnijeg rješavanja i analizepostavljenog problema, složena funkcija maksimalnog radaposmatrana je kao dvije funkcije sa jednom promjenljivomodnosno dvodimenzioni problem sveden je na dvajednodimenziona problema. Pokazano je da i kodjednodimenzionih problema takođe postoji tačka u kojoj jemaksimalni rad minimalan a različit od nule. Na kraj rada, date sumogućnosti primjene kompleksne problematike maksimalnograda a koje se odnose na eksergijsku analizu i optimizacijutermodinamičkih procesa, kao i smjernice za naredna istraživanjaproblema za slučaj ostalih gasova, poluidealnih gasova i Van derWaals – ovog gasa. Može se tvrditi, da postupak analizetermodinamičke funkcije maksimalnog rada, prikazanog u radu,nije uobičajen u literaturi.

Based on relations for the maximum work at the closed thermodynamic system, the paper presents implementation of a general model for determining the minimum storage volume for compressed air. Due to the mechanical and thermodynamic imbalance of observed model, there are the conditions for obtaining the maximum work. Derived relations, which represent a new model, can be directly used in technical practice for the case that are known parameters that define the initial state in the reservoir, the parameters of the environment, and energy to get from the compressed air. For a complete presentation of the reporting process, it is presented in the working p-v and thermal T-s diagram. In addition to the screening, the paper presents and graphic design of the problem, which can also be used to control of the results. Also, it is illustrated the application of the model on a practical case, where a certain minimum volume of the storage tank filled with air.