Aleksandra Sinik - Academia.edu (original) (raw)

Papers by Aleksandra Sinik

The quality of liquid soap for washing hands depends on its chemical composition, and it is evalu... more The quality of liquid soap for washing hands depends on its chemical composition, and it is evaluated by the
physicochemical and functional characteristics of that product. The aim of the work is to prepare different series
of liquid soap formulations by varying the concentrations of anionic and amphoteric surfactants and sodium
chloride, and to optimize the formulation. The effects of the optimization were evaluated based on the results of the
analysis of the physico-chemical parameters of the prepared formulations, such as density, viscosity, surface tension
and critical concentration of micelles. As amphoteric and anionic surfactant concentrations in liquid soap increase,
density and viscosity values increase. The value of the surface tension decreases with the increase in the
concentration of the surfactants present, with the amphoteric surfactant making a greater contribution to the
decrease. Regardless of certain advantages that the anionic surfactant shows in relation to the amphoteric one, the
best characteristics of the liquid soap are shown by the formulation that contains a combination of both used
surfactants. The addition of NaCl to the liquid soap formulation has multiple significance, but also a different effect
on the physical and chemical characteristics at lower and higher concentrations. Functional and some physicochemical
characteristics of liquid hand washing soap depend on the pH value of the formulation. As the pH value
increases, the surface tension and CMC increase to certain values, so pH=5.5 is taken as the optimal pH value of
liquid soap, as a compromise between the values of the measured characteristics and the pH value of human skin.
This research showed that the formulation containing 5.4 w/w% anionic surfactant, 1 w/w% amphoteric surfactant
and 4 w/w% NaCl represents the optimal liquid soap formulation.

GLASNIK HEMIČARA, TEHNOLOGA I EKOLOGA REPUBLIKE SRPSKE, 2018

Šume i šumska zemljišta se prostiru na preko 50% ukupne površine Bosne i Hercegovine. Srazmjerno ... more Šume i šumska zemljišta se prostiru na preko 50% ukupne površine Bosne i Hercegovine. Srazmjerno šumskom fondurazvijena je drvna industrija, posebno primarna prerada drveta, zbog ĉega BiH raspolaţe velikim koliĉinama, još uvijeknedovoljno iskorišćene, otpadne drvne biomase. U skladu sa postavljenim ciljem pribliţavanja zahtjevima EUpodsticanja proizvodnje i korišćenja obnovljivih izvora energije, BiH moţe ostvariti velike poslovne aktivnosti vezane zapreradu drvne biomase u drvni pelet. Cilj istraţivanja u ovom radu je bio ispitati uticaj hemijskog sastava i oblikasirovine najzastupljenijih vrsta drveća na prostoru BiH na kvalitet peleta od drvne biomase kao goriva.

Journal of the Serbian Chemical Society

Wood ash is a complex mixture of inorganic and organic compounds. It is heterogeneous in composit... more Wood ash is a complex mixture of inorganic and organic compounds. It is heterogeneous in composition, which can vary considerably. Ash is mainly disposed of in landfills, which creates a risk for air, soil and groundwater contamination by trace elements. In order for wood biomass ash to be used as a secondary raw material, it is necessary to perform leaching tests, to determine which microelements it contains, and which of them could be released into the environment during the ash disposal. Sequential extraction (SE) showed that in the exchangeable and carbonate fraction, the most volatile metals As, Cd, Zn and Pb are released the most from the ash of deciduous trees, while the leaching of ash from coniferous trees is significantly lower. The evaluation of risk assessment code (RAC) for the tested biomass ash samples, indicates that Pb is a high-risk leaching element due to its condensation on the ash particles. By performing toxicity characteristic leaching procedure (TCLP) and syn...

REMOVAL OF SODIUM LAURYL SULFATE FROM WASTEWATER BY ADSORPTION ON ACTIVATED CARBON, 2020

Sodium lauryl sulfate (SLS) is one of the main components present in detergents and personal hygi... more Sodium lauryl sulfate (SLS) is one of the main components present in detergents and personal hygiene products, therefore, it is the most common anionic surfactant substance in municipal wastewater, which during discharge endanger flora and fauna of the recipient. During the present study, adsorption of sodium lauryl sulfate (SLS) was performed from the wastewater suspension model sample onto powdered activated carbon (PAC). The experiment was performed at room temperature (20°C) and the pH value range of the initial model samples from 6,40 to 7,51. The influence of adsorbent dose (PAC), the adsorbate concentration (SLS), and adsorption time on the removal efficiency of SLS from the model sample were monitored. The process was additionally controlled by measuring the pH value. The use of powdered activated carbon gives satisfactory results in the removal of sodium lauryl sulfate from water, and the presented results of this research can serve as a foundation for further testing and implementation of this adsorption process for the removal of anionic surfactants from real wastewater samples.

Biomass use for energy purposes is an actual issue from different aspects, as economy, technologi... more Biomass use for energy purposes is an actual issue from different aspects, as economy, technologies used, combustion specifics, environmental issues, etc. Different biomass types are available on the market today, and due to their physical and chemical specifics, their behaviour in the furnaces is very diverse, from type to type. One of the problems related to biomass combustion is ash behaviour in the furnaces, and it is one of the key limitations for its use. This paper presents some of the experimental results related to combustion of pellets produced from wood, straw, and wastes from medical herbs production as well as some laboratory experiments related to use of solvents with the aim to eliminate some alkali elements from biomass before combustion process. In the pellet combustion experiments emissions of combustion products were measured, and after that analysis of the ash samples was performed. Measurements were performed on pure pellet samples and then on the samples to which some percentage additives were added (1 and 3% comparing to dry mass). Additives as kaolin, bentonite and clay, were used to improve ash melting characteristics. The results achieved from the analysis, shown different behaviour of different type of pellets during combustion process, and their reaction on additives use. It is also shown, that of diluted solutions (as hydrochloric acid) has an influence on porosity of lignocellulose materials and thus on heat transfer characteristics inside of fuel particle and combustion efficiency. It was concluded that some of the applied additives can be recommended because they had positive influence on the ash behaviour as well as some partial influence on the emissions of combustion products.

TECHNICAL SYSTEM CONDITIONS MONITORING VIA THE LUBRICATING OIL ANALYSIS, 2023

Oil monitoring consists of measuring the condition and changes in the structure and characteristi... more Oil monitoring consists of measuring the condition and changes in the structure and characteristics of engine oil over time of exploration. The tests performed on the oil sample give three pieces of information: the
condition of the lubricated system, the type of impurities present, and the condition of the oil itself. The state of the system is defined by the number and type of particles, as well as by the change of these parameters
with time. The condition of the oil is mostly defined by changes in viscosity, decrement in additives amount, contamination, etc. Proper oil monitoring enables an optimization of the working life of the lubricated system. Namely, the main cause of failure in the lubricated system is the presence of abrasive particles in the oil, which are often products of wear. Therefore, an analysis of wear and contamination must be performed, and the damage and cause of failure must be determined. Considering that it is impossible to eliminate wear, it is necessary to define the critical values of wear for the operation of the system and find the main causes of
wear. Intensive wear occurs with an increase in the number of large particles in the entire fluid volume, while in normal wear the particles are of small dimensions. The material from which the particles are made is also of great importance, through which we can determine the origin of the abrasive. Zn, Ca, Ba and Mg indicate the consumption of additives. Fe, Pb, Cu, Cr, Ag, Sn, Mn, and Al indicate wear. Penetration of the coolant into
the lubricating oil is indicated with the appearance of Na and B, and the increased content of Ca and Si indicates the contact of the oil with air or malfunction of the air filter. Oil sampling must be carried out exactly
in a certain way and on a certain part of the system through which the oil flows. Worn particles tend to settle to the bottom of the oil tank, larger particles settle faster and smaller ones more slowly. If we take a sample
by simply draining the oil from the reservoir, we can get an unrealistic picture of the actual condition of the lubricated system.

ЕКСТРАКЦИЈА НАФТНИХ УГЉОВОДОНИКА ИЗ ЗЕМЉИШТА, 2022

У току транспорта и употребе течних нафтних горива могуће су бројне незгоде које доводе до излива... more У току транспорта и употребе течних нафтних горива могуће су бројне незгоде које доводе до изливања одређене количине угљоводоника на земљиште. Паре изливених лако испарљивих нафтних угљоводоника загађују ваздух, а теже испарљиве компоненте мигрирају кроз земљиште и загађују га. Такође, кретањем кроз земљиште нафтни угљоводоници доспијевају до подземних вода и загађују их. Циљ рада је праћење динамике кретања угљоводоника из дестилационог подручја дизел горива (180-365 °C) кроз природну структуру земљишта током одређеног временског периода. Након тога, узорци земљишта са различитих дубина, подвргнути су екстракцији растварачем у апаратури по Soxhlet-у. Истраживање је проведено на реалним узорцима на одабраној локацији, за коју се претпоставило да претходно није
загађена угљоводоницима. Након екстракције угљоводоника из узорака загађеног земљишта, одређена је њихова количина и структура примјеном гасне хроматографије са детектором пламене јонизације (GC-FID).

РАЗВОЈ И ПРИМЈЕНА КОМПОЗИТНИХ ХИДРОИЗОЛАЦИОНИХ МАТЕРИЈАЛА, 2021

Поред традиционалних неорганских или само органских хидроизолационих материјала, последњих година... more Поред традиционалних неорганских или само органских хидроизолационих материјала, последњих година се интензивно развијају и примјењују савремени композитни хидроизолациони материјали, који спајају предности и једних и других. Хидроизолациони материјали имају широку примјену у заштити
темеља и подземних дијелова грађевинских објеката, купатила, балкона, базена, тунела, резервоара за воду и др. Примјеном композитних хидроизолационих материјала са побољшаним функционалним својствима, спречава се продор воде у унутрашњост грађевинских објеката, или истицање воде из базена и резервоара у знатно ширем подручју спољних фактора. Технологија припремних и завршних радова и уградња неквалитетног хидроизолационог материјала, изазвалa би велике штете на самом објекту и накнадне трошкове санације. У раду су описани резултати испитивања најважнијих функционалних карактеристика хидроизолационих маса, различитог хемијског састава, у циљу утврђивања њихових перформанси. Испитиване су дисперзионе хидроизолационе масе, хидроизолационе масе на бази цемента и полимер-цементне масе. Свим узорцима су одређене основне физичко-хемијске и механичке особине које су од изузетне важности за овај тип материјала. Резултати испитивања показују да савремени композитни хидроизолациони материјали имају одличну водоодбојност, високу
флексибилност и отпорност на механичке утицаје.

Natural gas, or compressed natural gas (CNG), is one of the most promising alternative fuels for ... more Natural gas, or compressed natural gas (CNG), is one of the most promising alternative fuels for transport vehicles. Previously, its application was limited to stationary engines, however, with the development of light composite materials for the production of tanks for storing this fuel on vehicles, a much wider application of CNG has opened up, namely on vehicles with engines that have compression ignition or spark ignition. The main constituent of natural gas is methane,
which has the highest H:C ratio in relation to the higher hydrocarbons that make up liquid petroleum fuels, and therefore releases the largest amount of heat during combustion, while the CO2 emission is the lowest. In order to achieve the best ratio between fuel consumption and emissions, it is necessary to achieve an optimal fuel/air ratio, which depends on the engine design, operating conditions and CNG composition. That is why it is very important to know the composition of natural gas, especially the concentration of its main component, methane, when it is used as a fuel for internal combustion engines. The paper describes the procedure for
determining the composition of natural gas using the gas chromatography method and ensuring the quality of test results in accordance with the requirements of the international standard ISO/IEC 17025. The results of the verification procedure of the standard method BAS EN ISO 6974-6, the creation of a control chart, the calculation of the measurement uncertainty and the results of the participation in the interlaboratory test in which 70 laboratories from 38 countries participated are listed.

The performance of an internal combustion engine can be tested on test circuit, chassis dynamomet... more The performance of an internal combustion engine can be tested on test circuit, chassis dynamometer and laboratory test benches. Laboratories equipped with test benches are most often used for engine testing because they provide the best accuracy and repeatability of measurement results. The engine testing laboratory of the Faculty of traffic and transport
engineering Doboj is equipped with an AVL Dyno perform engine test bench from the renowned manufacturer AVL Austria. The laboratory is equipped with measuring devices and actuators for conducting engine tests according to the ECE R85 standard. Engine performance testing was
performed on a VW BKC 1.9 TDI diesel engine. All tests were performed with a biodiesel mixture ratio of 20% m/m in mineral diesel fuel, the quality of which meets the requirements of the BAS EN 590:2018 standard. The paper presents the method of laboratory testing of the engine as well as the measurement results of the dynamic performance of the engine powered by diesel fuel and mixed exhaust diesel and biodiesel fuel.

Pellet combustion in small furnaces is a very actual subject, taking in to consideration installe... more Pellet combustion in small furnaces is a very actual subject, taking in to consideration installed number of devices, which rises every year. Taking in to consideration situation on the pellet market, it can be easily concluded that a pellet of very different quality appears in the offers. Combustion of pellets which are produced from different biomass types, has its own specifics, which are investigated in this paper. Investigation of combustion process was performed on laboratory installation in the furnace of household pellet fireplace, and it was investigated combustion of pellets produced from wood, straw, and rests from medical herbs production. Emissions of combustion products were measured, and after that analysis of the ash samples was performed. Measurements were performed on pure pellet samples and then on the samples to which some percentage additives were added (1 and 3% comparing to dry mass). Additives which were used are: kaolin, bentonite and clay. It was analysed effects of additives to emission of the combustion products, as well as melting characteristics and behaviour of the ash. The results achieved from the analysis, shown different behaviour of pellets produced from different types of biomass in the same measurements conditions. It was
concluded that some of the applied additives can be recommended in order to make positive influence on the ash behaviour and make some partial influence on the emissions of combustion products.

The professional literature dealing with specific aspects of adhesive joints in the footwear indu... more The professional literature dealing with specific aspects of adhesive joints in the footwear industry is mainly devoted to the procedures of preparation, bonding and testing of the connection between the upper and the sole material of fashion and sports footwear. However, there is little research related to the requirements and quality testing of adhesive joints of shoe upper parts. Safety and occupational footwear, which is intended for specific occupations such as firefighters, police officers, soldiers and others, as such has specific requirements in terms of resistance to various types of solvents, high and/ or low temperatures, shocks, etc., and in addition it should be comfortable and long-lasting. For these reasons, the upper of this type of footwear differs significantly from the footwear used in everyday life. It is usually a very complex construction and is made of a large number of different natural and artificial materials such as: leather, rubber, polyurethane, synthetic membranes, etc., which are interconnected by bonding or stitching. The aim of this study was to examine how the number of adhesive coatings and their characteristics affect the strength of the natural leather-rubber adhesive joint in the manufacture of shoes for special purposes. The strength of the leather-to-rubber adhesive joint depends significantly on the number of adhesive coatings and the viscosity of the adhesive.

The use of biomass for energetic purposes is actual issue from different aspect of views, such as... more The use of biomass for energetic purposes is actual issue from different aspect of views, such as economy, used technologies, combustion specifications, environmental issues, etc. Different types of biomass are available on the market today. During the combustion process in furnaces, these types of biomass behave differently due to their specific physicochemical properties. In this research, used biomass types were wood biomass, soybean straw and chamomile waste from medicinal herbs processing. Pellet combustion was performed in a commercial furnace that was designed to heat the living space by burningwood pellets. Furnace was installed with measurement system for emissions of combustion products. The current law regulation of the Republic of Srpska in the field of environmental protection does not include testing of emissions of combustion products for plants with power less than 100 kW. In this research, the influence of pellet type on concentrations of carbon monoxide and nitrogen oxides was investigated, as well as the volume content of oxygen in the waste gas for plants with power less than 100 kW. Also, it was investigated whether the addition of additives (clay, kaolinite, bentonite), used to improve the melting characteristics of ash, has an effect on reducing the emission of combustion products. The results obtained by measuring the gas emissions are compared with the standard EN 14785 which is related to the emission of carbon monoxide and nitrogen oxides. During this research, characteristic of ash left after combustion of tested pellets was examined. According to these examinations, it can be pointed out that potential problems can occur when burning these types of pellets in small household heating furnaces

In this paper, the corrosion test of copper in hydrocracked base oil HC-6 was performed in the pr... more In this paper, the corrosion test of copper in hydrocracked base oil HC-6 was performed in the presence of an additive for extremely high pressures (EP additive) in different concentrations. EP additives are used to reduce wear in industrial applications, under high load conditions. Since most of these additives are sulfur-based, whose compounds can be corrosive at high temperatures, their use leads to corrosion of some materials. To prevent corrosion in the base oil with the EP additive, three commercial corrosion inhibitors are added. By chemical composition, the inhibitor RC 8210 is a derivate of dimercaptothiadiazole, RC 4220 is a synthetic neutral calcium sulfonate, and IRGAMET 39 is a derivative of tolutriazole. Efficiency of the inhibitors was monitored by standard test methods for corrosiveness to copper arising from petroleum products by the copper strip test (ASTM D-130) and the gravimetric method, while oxidation stability of the base oil was monitored by peroxide number determination. Oxidation was performed at 100±1 o C for 3 and 24 h. Results of these studies have shown that IRGAMET 39 is the most effective inhibitor in the presence of the EP additive at both examined oxidation times.

Leaching of heavy metals from wood biomass ash, before and after binding in cement composite, 2022

The introduction of different additives into the cooling and lubrication systems in the metal cut... more The introduction of different additives into the cooling and lubrication systems in the metal cutting process, contributed to improving the machining process sustainability. Different types of additives can help to reduce friction, reduce wear of contact surfaces, improve heat dissipation from the cutting zone, etc. With the development of nanotechnology, great focus has been placed on the investigation and using of nano-particles, nano-additives and nanofluids in industry. In this paper, the effects of using the nano-particle based cooling and lubrication fluid are investigated. There are performed comparison effects of standard cooling and lubrication fluids versus nanofluids based cooling and lubrication on cutting process performance. Molybdenum disulphide particles are used as nano-particles, which dispersed in a standard cooling and lubrication fluid. As workpiece was used alloyed tool steel. Milling process performance indicators was analysed based on Taguchi experimental plan, for different cooling and lubrication condition and process parameters. Cutting forces component in three perpendicular axes, and machined surface parameters were measured. Experimental analysis has shown that the use of nano-particles, which mixed in a standard cooling and lubrication fluid, significantly contributes to the reduction of cutting forces, friction coefficients, more efficient cutting and generation of machined surfaces.

Glasnik hemičara, tehnologa i ekologa Republike Srpske, Jul 19, 2018

Forest and forest lands spread on over 50% of the total area of Bosnia and Herzegovina. Forest in... more Forest and forest lands spread on over 50% of the total area of Bosnia and Herzegovina. Forest industry was developed in proportion to the forest fund, especially primary wood processing. Because of that there are large amounts of waste wood biomass, still underutilized. In accordance with set goals of approaching EU requirements, incentives for production and use of renewable energy sources, B&H can achieve big business activities related to processing wood biomass. The aim of the research in this work was to examine the impact of the chemical composition and the shape of the raw material of the most common wood types in the area of B&H on the quality of wood biomass pellets as a fuel. The impact of moisture resins and fats content, lignin, and also the impact of the shape of raw material, on calorific value of pellets are tested. Wood pellets analyzed for this study are industrially produced in the plant for pelletization in Srbac. As a starting material for the production of wood pellets, various forms of wood waste remains of primary wood processing were used. Those are: chips from sawmill residues without bark, chips with higher percentage of bark, sawdust and chips from sawmill without bark, which were collected across Bosnia and Herzegovina. By analysing key quality parameters, such as moisture content, ash content and lower heating value, and threshold values defined by ENplus standard for wood pellets, it was concluded that all tested samples do not meet the prescribed standards. For the successful use of wood pellets it is very important to standardize quality and adherence to adapted standards in production.

GLASNIK HEMIČARA, TEHNOLOGA I EKOLOGA REPUBLIKE SRPSKE, 2022

Due to the limited availability of wood, as the highest quality raw material for the production o... more Due to the limited availability of wood, as the highest quality raw material for the production of biomass pellets, increasing attention is being paid to the production and use of pellets from low-quality materials such as different types of agricultural waste. However, the complex chemical composition of these types of biomass often leads to various problems during their combustion. One of the biggest problems when it comes to burning biomass pellets is related to the low melting temperature of the resulting ash and its tendency to sintering. By modifying the chemical composition of biomass, it is possible to influence the method of combustion and the characteristics of residual ash. Modification of biomass composition can be carried out by chemical pretreatment with acids, which reduces the concentration of alkali metals and alleviates ash adhesion and the tendency to form slag. Pellets made from wood biomass, soy straw and chamomile waste from the process of processing medicinal ...

Zastita materijala, 2023

Today, huge amounts of coloured wastewater, released into ecosystems are a big problem, because t... more Today, huge amounts of coloured wastewater, released into ecosystems are a big problem, because they have harmful effects on humans, the environment, as well as the aquatic environment. One of the common treatments for removing dyes from wastewater is the adsorption process, with an emphasis on the use of cheap adsorbents. Therefore, the subject of this paper is the possibility of removing the anionic dye bemacid red (BR) on wood biomass sawdust and carbonized sawdust. The experiments examined the equilibrium contact time, the effect of initial pH, the effect of adsorbent dose, as well as the effect of the initial adsorbate concentration on the process of adsorption. By applying linear kinetic models, it was found that the adsorption process follows a pseudo-second-order kinetic model. It was found that pH does not have a significant effect on adsorption onto carbonized sawdust. By examining the effect of the initial adsorbent dose, it was found that optimal adsorption requires twic...

GLASNIK HEMIČARA, TEHNOLOGA I EKOLOGA REPUBLIKE SRPSKE, 2021

Adsorption, as an easy and effective technique, is widely used to remove a large number of dyes f... more Adsorption, as an easy and effective technique, is widely used to remove a large number of dyes from aqueous solutions. Activated carbon is the most desirable adsorbent, but due to its high cost, its use is limited. Proving the possibility of adsorption and its efficiency performed on cheap adsorbents is a great challenge and interest of many researchers in the past few decades. In this paper, unmodified (P) and modified sawdust obtained in two ways (HCl treatment and NaOH treatment), labeled as PHCl and PNaOH, are used for the removal of the methylene blue dye. Adsorption experiments showed that the optimal time for adsorption is different, for the sample PNaOH – 30 min, for the sample P – 45 min, and for the sample PHCl – 60 min. By applying nonlinear kinetic models to the experimentally obtained data, it was found that the best model that describes this adsorption is pseudo-second-order model. By examining the effect of pH values on adsorption, different results were obtained (fo...