Ash Fraction Research Articles

Complex Technology of Ash and Slag Waste from Power Plants

The development of a comprehensive technology for the processing of ash waste (ASW), which is based on the extraction of carbon from the CSO by flotation method and iron-containing minerals by means of magnetic separation, is presented. The proposed approach is based on the extraction of carbon from ash and slag by flotation and iron-containing minerals by magnetic separation. In this work, the optimal size of the ash fraction supplied for flotation was established. It is shown that when the technological process is carried out according to the stadium scheme when flotation reagents are fed in fractions, it allows their consumption to be reduced and the recovery of carbon concentrate from underburning to be significantly increased. The developed technology was tested on a pilot plant. High-quality carbon, iron-containing and aluminosilicate products were obtained. Auxiliary enrichment processes such as classification, thickening and filtration were tested.

Composition of inorganic components in <i>Helianthus tuberosus</i> stems

This article studies inorganic components in Heliánthus tuberósus stems. Ash samples and extracts obtained at different pH values were examined. It is established that the extractant's nature has a significant effect on the yield of extractive substances from the ground stems: the greatest (45%) and the minimum (31%) yield was achieved by sodium hydroxide and distilled water, respectively. According to atomic absorption spectrometry, the main ions in the extracts obtained in different media are those of potassium, calcium, sodium, magnesium and iron. Following treatment of stems with solutions having different pH values, the mass fraction of ash varied from 0.4 to 2.3%. The smallest ash yield was observed for a stem sample after acid extraction. According to energy dispersive X-ray fluorescence spectrometry, all ash samples contained predominantly K, Ca, Si and P compounds. Acid hydrolysis produced the highest level of Si in samples, which allows this ash to be used as a silicon-containing material. The ash components of the core and outer part of the stem were compared with the initial sample. According to the nature of thermal decomposition, the initial sample and the outer shell were similar between themselves, though differing from the core. The ash content of the initial sample was 4.3%, with the ash content of the stem core being ~2 times higher than that of the outer shell (7 and 3.8%, respectively). The results of IR spectroscopy showed that splitting of bands in the IR spectra of ash samples depend on the part of the stem and the pre-treatment of raw materials at different pH values. The ash of the initial sample, core and outer shell, as well as the ash of the residues after the aqueous and alkaline hydrolysis of the stem, showed the absorption bands of carbonate groups. The IR spectra of the stem ash after acid extraction contained absorption bands characteristic of amorphous silicon dioxide. According to the conducted X-ray analysis, the studied ash samples were in an amorphous-crystal and crystalline state. The identification of phases was carried out.

Improvement of the fine coking coal flotation technolgy

The paper presents data on the development of a reagent regime for the flotation of fine coal fractions of –0.5+0 mm. The study focuses on coking coal from the Butovskaya mine (Kemerovo coal deposit, Russia). The ash content in the rock mass mined ranges from 23 to 30 %. Using the methods of optical microscopy, the presence of rock-forming minerals in the flotation feed, mainly represented by silicates (quartz), was established, which supports the addition of liquid glass to the process as a depressant for silicates. The study of the flotation kinetics allowed establishing the coal flotation time for a more complete recovery of the combustible matter. The paper compares the basic and alternative reagent regimes. The basic regime is represented by an apolar collector in the form of a mixture of hydrocarbon liquids of petroleum origin and a frother containing oxygen-bearing chemical compounds of various molecular structures in its group chemical composition. The alternative regime includes a depressant (liquid glass), an apolar collector (diesel fuel), and a frother represented by a mixture of aliphatic alcohols, ethers, and esters. Using the technology developed, coal flotation concentrate was obtained with the mass fraction of ash of 7.36 % and recovery of 9.78 %, allowing to generate a product meeting the requirements of GOST R 51588-2000.The work was carried out with the support of the Russian Science Foundation (project No. 19-17-00096).

Изучение пищевой ценности яиц куриных пищевых, реализуемых на рынке Республики Беларусь

The subject of research – nutritional value, morphological parameters and caloric content of food chicken eggs of various weight categories, laid in different time periods (autumn, winter, spring, summer). The purpose of research – is to study the nutritional value of chicken eggs sold on the market of the Republic of Belarus during different seasons. Methods. The objects of research were: chicken eggs of the highest, selected, first and second categories. The content of protein, fat, dry matter was carried out according to GOST 30364.1-97, the fraction of ash - according to GOST 31727-2012, carbohydrates - in accordance with the «Guidelines for laboratory quality control of products in public catering» No. 18/29 of 21.04.2001. The mass of one egg was determined by weighing it on a laboratory scale ML B1JA «Newton» with an accuracy of 0.1 g. The mass of the components of the egg (protein, yolk and shell) was determined by morphological analysis during weighing and opening the egg. The results of the study. The average data of the content of proteins, fats and energy value were obtained: the mass fraction of protein substances – 12.1±0.73 %; the mass fraction of fat – 10.5±0.83 %; the energy value – 142.9±0.47 kcal/100 g. Morphological studies were also carried out to assess the effect of the ratio of the components of the egg on its energy value. The average data of the protein/yolk ratios depending on the category were obtained, on the basis of which it was concluded that eggs of all categories sold in the territory of the Republic of Belarus are within the limits set in the literature data (1.5:1–2.9:1), at the same time, the closest to the optimal level (1.9:1–2.1:1) of the ratio of protein/yolk is characteristic for the eggs of the first category. It is determined that the Shtele-Filatov formula can be used for the accelerated determination of the caloric content of eggs. Scope of research results. The average data on the nutritional value of chicken eggs obtained during the research will be included as information in STB 254 “Edible hen’s eggs. Specifications” when it is updated

Single Pellet Combustion of Sewage Sludge and Agricultural Residues with a Focus on Phosphorus

Recycling of phosphorus in combination with increased utilization of bioenergy can mitigate material and global warming challenges. In addition, co-combustion of different fuels can alleviate ash-related problems in thermal conversion of biomass. The aim of this study is to investigate the ash transformation reactions of mainly P in co-combustion of P-rich sewage sludge (SS) with K-rich sunflower husks (SH) and K- and Si-rich wheat straw (WS). Single pellets of 4 mixtures (10 and 30 wt % SS in WS and 15 and 40 wt % SS in SH) and pure SS were combusted in an electrically heated furnace at process temperatures relevant for fluidized bed combustion (800 and 950 °C). Collected ash fractions were analyzed by inductively coupled plasma techniques, ion chromatography, scanning electron microscopy–energy-dispersive X-ray spectroscopy, and X-ray diffraction. Thermodynamic equilibrium calculations were performed to interpret the results. Over 90% of K and P was found to be captured within the residual ash with 30–70% P in crystalline K-bearing phosphates for mixtures with low amounts of SS (WSS10 and SHS15). The significant share of K and P in the amorphous material could be important for P recovery. For the lower percentage mixtures of SS (WSS10 and SHS15), P in crystalline phases was mainly found in K-whitlockite and CaKPO4. For the higher percentage SS mixtures, most of P was found in whitlockites associated with Fe and Mg, and no crystalline phosphates containing K were detected. For P recovery, co-combustion of the lower SS mixtures is favorable, and they are suggested to be further studied concerning the suitability for plant growth.

Combined Effects of Exercise and Denosumab Treatment on Local Failure in Post-menopausal Osteoporosis-Insights from Bone Remodelling Simulations Accounting for Mineralisation and Damage.

Denosumab has been shown to increase bone mineral density (BMD) and reduce the fracture risk in patients with post-menopausal osteoporosis (PMO). Increase in BMD is linked with an increase in bone matrix mineralisation due to suppression of bone remodelling. However, denosumab anti-resorptive action also leads to an increase in fatigue microdamage, which may ultimately lead to an increased fracture risk. A novel mechanobiological model of bone remodelling was developed to investigate how these counter-acting mechanisms are affected both by exercise and long-term denosumab treatment. This model incorporates Frost's mechanostat feedback, a bone mineralisation algorithm and an evolution law for microdamage accumulation. Mechanical disuse and microdamage were assumed to stimulate RANKL production, which modulates activation frequency of basic multicellular units in bone remodelling. This mechanical feedback mechanism controls removal of excess bone mass and microdamage. Furthermore, a novel measure of bone local failure due to instantaneous overloading was developed. Numerical simulations indicate that trabecular bone volume fraction and bone matrix damage are determined by the respective bone turnover and homeostatic loading conditions. PMO patients treated with the currently WHO-approved dose of denosumab (60 mg administrated every 6 months) exhibit increased BMD, increased bone ash fraction and damage. In untreated patients, BMD will significantly decrease, as will ash fraction; while damage will increase. The model predicted that, depending on the time elapsed between the onset of PMO and the beginning of treatment, BMD slowly converges to the same steady-state value, while damage is low in patients treated soon after the onset of the disease and high in patients having PMO for a longer period. The simulations show that late treatment PMO patients have a significantly higher risk of local failure compared to patients that are treated soon after the onset of the disease. Furthermore, overloading resulted in an increase of BMD, but also in a faster increase of damage, which may consequently promote the risk of fracture, specially in late treatment scenarios. In case of mechanical disuse, the model predicted reduced BMD gains due to denosumab, while no significant change in damage occurred, thus leading to an increased risk of local failure compared to habitual loading.

Honey as a component of marinade for semi-finished meat products

The specific features of the biochemical composition and properties of raw meat determine the necessity of finding new technologies for its processing to obtain new products with high consumer properties. The actual area of technology development is the enrichment of raw meat with useful components with functional and technological properties that have high biological value: api products and products of plant origin.The purpose of the work was to develop a marinade with the addition of honey and to explore its effect on the semi-finished meat product, depending on the duration of marinating. Selection of samples for investigations and their preparation for analysis was performed according to GOST 4288-76 “Culinary and semi-finished products of minced meat. Acceptance rules and test methods”, organoleptic examinations were performed according to DSTU 4426:2005, moisture content determination – GOST 9793-74 “Meat products. Methods for determination of moisture”, the amount of fat – for GOST 23042-86 “Meat and meat products, “Methods for determination of fat”, the amount of protein – GOST 25011-81 “Meat and meat products. Methods for determination of protein”, determination of ash content – GOST 31727-2012 “Meat and meat products. Determination of mass fraction of total ash”, determination of pH – GOST 26188-84 “Products of fruits and vegetables processing, canned meat and meat. Determination of pH”, and determination of fibre-forming and fibre-retaining properties were performed through sample preparation and determination of fibre content. According to the scheme of the experiment, the research technology was determined. The research results of the initial raw meat, honey and marinated semifinished product are presented in the study. It was established that the decrease in the pH of the marinated semi-finished product during the 24-hour exposure period ensures the stability of the meat to storage, as most bacteria develop at high pH values, while on acidic nutrient media below 6.2, their development is slowed down. Long marinating allows obtaining meat with increased moisture binding and moisture retention capacity and improved consistency and juiciness. The task of establishing new products requires new approaches and techniques of technology. Using apiproducts that have antioxidant properties will allow refraining from using preservatives and stabilisers of chemical origin. Thus, honey can be used in the composition of marinated meat products. The introduction of active components of honey into the marinade will extend the shelf life and adjust the organoleptic properties. In addition, during heat treatment, the meat marinated with honey marinade acquires new taste qualities, and the appearance becomes brighter due to the caramelisation of honey

Economic cost\u2013benefit analysis for the agricultural use of sewage sludge treated with lime and fly ash

A tool for calculating the economic and environmental impacts of the use of byproducts of industrial processes that can substitute for perishable resources was presented. This was exemplified by fly ash (the fine fraction of ash originating from coal burned to generate electricity and collected by filtering exhaust gases leaving the furnace), added to soil as a component of sewage sludge stabilized with fly ash and lime (NVS). Application to soil of NVS has potential agricultural and environmental advantages and disadvantages. The costs and benefits of such application were calculated using both a database and expert opinions. The calculations assumed a representative assemblage of soils and crops, with weights assigned to each crop type and soil characteristic. The annual weighted benefits (additional income for the farmer) and costs per hectare reached 324 $/ha and 131 $/ha respectively. Major potential benefits include: Chemical fertilizer replacement, 159 $/ha; Improvement to the soil's physical properties, 75 $/ha; Supply of vital trace elements, 33 $/ha. Major potential costs were: Regulatory limitations on marketing of crops pending proof of absence of risk of heavy metals or radionuclides accumulation in these crops, (17 $/ha and 36 $/ha respectively); Application and incorporation cost, 50 $/ha. The presented estimates of the costs and benefits refer to the array of soils and conditions typical to Israel. It is possible to maximize potential benefits by applying fly ash only to the most suitable agricultural soils while improper use of fly ash will increase the costs incurred from its use.

Characteristic properties and recyclability of the aluminium fraction of MSWI bottom ash.

The increasing use of aluminimum in packaging applications results in many different aluminium-based products ending up in consumer mixed-waste bins. This waste is typically incinerated, generating an aluminium-containing bottom ash. The current work investigates the recyclability of the aluminium fraction in the bottom ash from waste incineration plants in the USA, UK and Denmark. Incinerated Al-samples from different size fractions (2-6mm, 6-12mm and 12-30mm) were characterized in terms of inherent oxide thickness, re-melting yield/coagulation and composition. The measured average oxide thickness on Al particles was 68µm(SD=100), with the metal yield and coagulation efficiency measured to between 76 and 92% and 87-99% respectively. Larger particle size fractions resulted in a higher metal yield due to their higher mass to surface ratio. A simplified model correlating metal yield and particle size was proposed. The aluminium content of the melted material was determined to between 95.6 and 98.5% with main impurities being Fe, Si, Mn, Zn, Mg and Cu, corresponding to major aluminium alloying elements and waste charge components.

Morphology, chemical and mineralogical composition of magnetic fraction of coal fly ash

The article presents in detail the geochemical and mineralogical characteristics of magnetic particles formed during energetic combustion of hard coal and lignite. The aim of the research was to assess their suitability as a source of possible raw materials necessary for the development of new technologies. Both hard coal and lignite fly ash, as well as the magnetic fractions separated from them, have been tested using various analytical methods.The chemical composition, phase composition, the size, and morphology of magnetically susceptible particles were determined. The main phases identified in the magnetic fraction are magnetite, hematite, and multicomponent phases, often trapped in aluminosilicate or calcium-aluminosilicate basic glass. In order to compare the chemical composition of the magnetic fractions and raw ashes, EF was calculated - the enrichment factor of the component in the magnetic fraction in relation to ash. Among the elements that have been enriched, apart from Fe, the following should be mentioned: Mg, Mn, Co, Nd, Cu, Ni, and Au. Only the concentrations of Cu and Ni in the magnetic fraction of lignite are much higher than the Clarke value (average concentration in ash), therefore the recovery of these raw materials can only be profitable from this ash. Research confirmed that when choosing the waste for the separation of metal concentrates, the content of the raw material in the ash is not always the most important, but also the form of its occurrence.

THE RESEARCH AND USE IN CONSTRUCTION OF THE BY-PRODUCTS FROM THE THERMAL POWER PLANT HYDRAULICALLY REMOVED ASH CLASSIFICATION

Today the environment protection is one of the most important issues in the world. The utilization of accumulating industrial waste is an up-todate area of construction research. The paper suggests a method for processing an electricity production waste, namely an ash from the hydraulic removal in the thermal power plant (TPP). The special classification by fractions of ashes from the hydraulic removal allows to receive such products as iron-containing product, fine sand (coarse filler), aluminosilicate hollow microsphere, and product with pozzolanic activity (fine filler).The experts of the State Enterprise "The State Research Institute of Building Constructions" and "Engineering Company "Perspective"" have conducted a series of studies on the obtained products properties and chemical composition, as well as on determining the fractional composition of each product. The density and specific surface area were evaluated, and each product binding properties control was performed. It was found that the aluminosilicate hollow microsphere and the product with pozzolanic activity had binding properties, and hardened mortars based on these materials were insoluble in water. Chemical analysis showed that in each of the products, except for iron-containing one, oxides of silicon and aluminum predominated. The iron containing product had a high content of iron oxides and by its composition was close to magnetite.The carried-out studies show that the products obtained during the hydraulic ash removal at TPP have a wide range of applications, both in the construction industry and in the chemical, mining, and metallurgical industries. In construction, these materials can be widely used as active mineral additives in the grinding of cements, or as additives improving the concrete mixtures and concretes properties. The iron-containing product is applicable in the special ultraheavy concretes manufacture.

Effects of fibre source on nutrient digestibility of diets for finishing lambs

Inexpensive fibre sources might be used as an alternative to lucerne hay in diets for finishing lambs. Thus, effects of providing fibre from lucerne hay (LH), soyhulls (SH), maize stover (MS) and Eragrostis teff hay (ET) on the nutrient digestibility of diets of finishing lambs with comparable NDF and nutrient concentration were evaluated. Thirty-six individually housed Merino ram lambs (x̄ = 43.03, SD = 3.72 kg) were randomly allocated to four diets (n = 9 lambs/treatment). A digestibility study was conducted to determine the nutrient availability of these diets. Dry matter (DM) intake of SH (1436 g) was lower than ET (1716 g). No differences were recorded between treatments for digestibility of NDF (0.32 - 0.34), acid detergent fibre (ADF) (0.41 - 0.44), and ether extract (EE) (0.67 - 0.75), except that MS (0.23) had lower NDF digestibility. Digestibility of DM, organic matter (OM) and non-structural carbohydrates (NSC) were similar for the LH (0.72; 0.75; 0.96) and SH (0.70; 0.74; 0.95) diets, whereas digestibility of crude protein (CP) (0.71 vs. 0.68), metabolizable energy (ME) (9.49 vs. 8.90 MJ/kg DM), and the available ash fraction (0.39 vs. 0.28) were altered. The SH and ET (8.70 MJ/kg DM) treatments had similar ME concentrations, but ET had lower DM digestibility (0.68). The MS treatment had the lowest ME concentration (8.25 MJ/kg DM). The LH treatment resulted in overall better nutrient availability compared with SH, MS, and ET.

Development of methods for standardization of Crocus sativus (saffron) stigmas for inclusion in the draft monograph of the State Pharmacopoeia of Ukraine

Crocus sativus L. from the Iridaceae family is a medicinal and edible plant that has recently been actively cultivated in Ukraine. Saffron spice is crocus flower stigmas exhibiting a wide range of the pharmacological activity due to its three main bioactive compounds: crocin, picrocrocin and safranal. The quality of this raw material is regulatedby various normative documents, but there is no monograph in the State Pharmacopoeia of Ukraine (SPhU). Aim. To perform a comparative analysis of the monograph “Saffron for homoeopatic preparations” from the Ph. Eur. 9.0, “Saffron. Croci stigma” from the Deutscher arzneimittel codex (DAC) and “Spices – Saffron (Crocus sativus L.)” from the ISO 3632 by the following indicators: description, identifcation (microscopy and TLC), impurities, loss on drying, total ash and quantifcation of crocin, picrocrocin and safranal by UV-Vis-spectrophotometry to clarify the possibility of harmonizing the requirements of the national legal framework for Crocus stigmas withthe Ph. Eur. 9.0, DAC and ISO 3632. The results of the analysis will be taken into account in the development of the monograph of the national part of the SPhU “Crocus stigmas (saffron)”.Results and discussion. The quality indicators of Crocus stigmas and their standardization determinedby the monograph in the Ph. Eur. 9.0, DAC and ISO 3632 on the raw material studied have been analyzed; some differences in the regulated quality indicators of the raw material have been found. The results of our own research have shown that the samples of the Ukrainian Crocus (saffron) meet all these requirements. The results of the macro- and microscopic examination of the raw material are given. The chromatographic examination hasbeen performed in accordance with the Ph. Eur. 9.0 and DAC using crocin as a standard compound; the quantitative determination of crocin, picrocrocin and safranal in 8 samples of Crocus stigmas has been performed by UV-Vis-spectrophotometry in accordance with the ISO 3632. It has been proposed to introduce the following indicators to determine the specifc absorption rate: for crocin (C44H64O24; Mw – 976.70) not less than 180, for safranal (C10H14O; Mw – 150.22) – not less than 30, for picrocrocin (C16H26O7; Mw – 330.37) – not less than 60 calculated with reference to the dried raw material.Experimental part. For analysis the dried stigmas of Crocus sativus (saffron) collected in the villageLyubimivka, Kherson region, Ukraine (2016-2018), as well as commercial samples of saffron from Morocco,Azerbaijan, Spain were used. The analysis of the leading normative documents containing monographs “Crocus stigmas”, among them the Eur. Ph. 9.0, DAC and ISO 3632, was performed. The studies included description of the appearance of the whole Crocus stigmas; loss on drying and the mass fraction of volatile compounds (105 °C, 16 h); the mass fraction of total ash. The amount of picrocrocin, safranal and crocin was measured by direct reading of the absorption of 1 % aqueous solution of stigmas at 257 nm, 330 nm and 440 nm, respectively, usinga UV-Vis-spectrophotometer.Conclusions. The analysis of the requirements to quality of the medicinal raw material – stigmas of Crocus sativus – has been performed based on the monographs: “Saffron for homoeopatic preparations” from the Ph. Eur. 9.0, “Saffron. Croci stigma” from the Deutscher arzneimittel codex and “Spices – Saffron (Crocus sativus L.)” from the ISO 3632. The main criteria for standardization of the raw material have been determined. It has been proposed to introduce the monograph to the national part of the SPhU “Crocus stigmas (saffron)” according to the following requirements: identifcation (macro- and microscopic signs; thin-layer chromatography (crocin); the quantitativedetermination (the content of crocin, picrocrocin and safranal) adapted to the ISO 3632, performed by UV-Vis-spectrophotometry; impurities; loss on drying; total ash.Key words: standardization; State Pharmacopoeia of Ukraine; Crocus sativus stigma; saffron; crocin

Integration of Air Classification and Hydrothermal Carbonization to Enhance Energy Recovery of Corn Stover

Air classification (AC) is a cost-effective technology that separates the energy-dense light ash fraction (LAF) from the inorganic-rich high ash fraction (HAF) of corn stover. HAF could be upgraded into energy-dense solid fuel by hydrothermal carbonization (HTC). However, HTC is a high-temperature, high-pressure process, which requires additional energy to operate. In this study, three different scenarios (i.e., AC only, HTC only, and integrated AC–HTC) were investigated for the energy recovery of corn stover. AC was performed on corn stover at an 8 Hz fan speed, which yielded 84.4 wt. % LAF, 12.8 wt. % HAF, and 2.8 wt. % below screen particles. About 27 wt. % ash was reduced from LAF by the AC process. Furthermore, HTC was performed on raw corn stover and the HAF of corn stover at 200, 230, and 260 °C for 30 min. To evaluate energy recovery, solid products were characterized in terms of mass yield, ash yield, ultimate analysis, proximate analyses, and higher heating value (HHV). The results showed that the energy density was increased with the increase in HTC temperature, meanwhile the mass yield and ash yield were decreased with the increase in HTC temperature. Proximate analysis showed that fixed carbon increased 18 wt. % for original char and 27 wt. % for HAF char at 260 °C, compared to their respective feedstocks. Finally, the hydrochar resulting from HAF was mixed with LAF and pelletized at 180 bar and 90 °C to densify the energy content. An energy balance of the integrated AC–HTC process was performed, and the results shows that integrated AC with HTC performed at 230 °C resulted in an additional 800 MJ/ton of energy recovery compared to the AC-only scenario.

Numerical modeling of a batch fluidized-bed gasifier: Interaction of chemical reaction, particle morphology development and hydrodynamics

The present study aims to analyze the interaction of chemical reactions, particle morphology change and hydrodynamics in fluidized-bed gasifiers. The char gasification in a batch fluidized-bed gasifier was modeled. The two-fluid model approach was coupled with an extended version of the uniform conversion model accounting for inert ash fraction. Model assumptions were confirmed via measurement of char density, porosity and particle size distribution at different stages of conversion in a lab-scale fluidized-bed gasifier. The CFD model correctly predicts the effects of particle structure change on chemical reactions, approved by a first of its kind comprehensive validation against unsteady experiments. Based on the validated CFD model, the interaction of hydrodynamics and local particle density variations due to chemical reactions is analyzed, and the effect of the initial bed height is studied.

Assessment of Honey Quality from the Middle Podrinje Area

The study aimed to examine the quality of honey from the Middle Podrinje area (Bosnia and Herzegovina). The research included a total of 21 samples of honey from the Middle Podrinje area: 12 samples of honey florals (municipalities of Srebrenica and Milići), 9 samples of acacia honey (municipalities of Zvornik and Bratunac). Physico-chemical parameters were determined as the main composition criteria for quality assessment in honey samples: mass fraction of water, total acidity, electrical conductivity, and ash. Samples of honey florals are of poorer quality compared to acacia honey, two samples had values of water content and acidity above the values prescribed by the Regulation. Statistical analysis showed that there is a statistically significant difference between the arithmetic means of the water content for floral honey, the electrical conductivity of acacia honey, and the free acid content for both types of honey. Honey samples that met the criteria prescribed by the Regulation were sensory evaluated by experienced analysts. Two samples of floral honey that did not meet the criteria prescribed by the Regulation were not sensory evaluated. Based on sensory analysis, samples of floral honey from the municipality of Milići had better sensory characteristics compared to the same type of honey from the municipality of Srebrenica. Acacia honey from the municipality of Zvornik was rated better than honey from the municipality of Bratunac.

Development of primary reference measurement procedure and reference materials for mass fraction of crude fat (oil content) in oilseeds and other products on their base

The article is devoted to development of metrological support for measurements of mass fraction of crude fat (oil content) value which is hard to explain and generalised quality value of oilseeds and produced on their oilseeds residues, cereals and pulses, foodstuff and its components. Results of this value measurement depend on conditions of analysis and testing samples matrix. The problem of insuring of the results compossibility can be solved by the development of primary reference measurement procedure (PRMP) as well as development of related reference materials for transfer of the units to the results of routine measurements. As the basic method was taken modified extractive method - Randall’s method of quantitative extraction of free and chemical or mechanical bound fat from product samples followed by measurement. Development of PRMP included the optimisation of the parameters of the measurement of the possible limits of their variation, as well as evaluating components of the uncertainty of measurement taking into account contributions related to influence on the measurement results of the applied equipment and reagents, equations, measurement, methodological factors, the heterogeneity of samples. The extended uncertainty of the measurement results of the mass fraction of crude fat (oil content) at the coverage coefficient k=2 was 0.15 %, providing a margin of accuracy of the developed PRMP concerning standardised measurement methods from 2.7 to 13.3 times. Comparisons of measurement results of crude fat mass fraction (oil content) in the seeds of: sunflower, soy, rape plant, mustard, flax by PRMP and GOST 10857-64, GOST 32749-2014, GOST 8.597-2010 vindicated the absence of result biases according to PRMP in compare with the routine methods results. Developed PRMP for crude fat (oil content) mass fraction in oilseeds and other products on their base (FR.PR1.31.2019.00009) together with PRMP for mass fraction of ash in nutritive products and food ingredients (FR.PR1.31.2018.00002), and state standards for system of units GET 173-2017, GVET 176-1-2010 was used for characterisation of 14 types of reference materials such as GSO 11268-2019/ GSO 11270-2019; GSO 11279-2019/ GSO 11283-2019; GSO 11284-2019/ GSO 11289-2019.

Mechanical properties and microstructure of lightweight polymer composites containing mono and hybrid fillers sourced from recycled solid wastes

This paper presents the development of lightweight polymer composites containing various solid wastes as fillers. This research is conducted to formulate mix proportions of polymer composite using unsaturated polyester resin as binder and waste tyre rubber crumb, recycled polyethylene terephthalate (PET) flakes and fly ash as fillers. Effects of various volume fractions of rubber crumb, PET flakes and fly ash and their combinations on 3 days compressive strength and density of the polymer composites are studied and a number of optimum mixes are selected for further study. Compressive strength, flexural strength and toughness of the above optimum mixes are measured at 3, 14 and 28 days. The effect of jute fabric as reinforcing layer on flexural strength and toughness of polymer composite is also studied. Microstructure analysis is conducted to investigate the polymer matrix and matrix-fillers interface of the composites. The optimum mix proportions are developed based on usage of least binder and high volume of filling materials, having lightweight and appreciable compressive strength. Results show that the 28-day density and compression strength of polymer composites are in the range of 1072 to 1616 kg/m3 and 15 to 62 MPa, respectively. These values are well below the American Concrete Institute (ACI)’s lightweight concrete density of 1850 kg/m3 and compressive strength of 17.5 MPa. The combined use of fly ash with rubber crumb or PET flakes improved the compressive and flexural strengths of polymer composites compared to the use of rubber crumb or PET flakes alone. The use of jute fabric increased the flexural strength and toughness of polymer composites. Microstructural analysis revels no additional substance besides binder and fillers, indicating no reaction of fillers with the resin in the composite.

Characteristics of coal dust deflagration under the atmosphere of methane and their inhibition by coal ash

To investigate the flame propagation of coal dust deflagration and the inhibition characteristics of coal ash which as a mixed inert powder under the atmosphere of methane. A vertical combustion pipe with half-open was built to study the methane/coal dust deflagration at different concentrations of coal dust and different mass fractions of coal ash. The residues after coal dust deflagration were characterized by SEM, XPS and FTIR. Results indicate that the deflagration intensity of coal dust firstly increases and then decreases with the increasing of coal dust concentration. Under this experimental conditions with 7 vol% methane/air, the optimum deflagration phenomenon appears at the dust concentration of 200 g/m3. After the addtion of coal ash, the decomposition of coal dust was prevented to some extent for its heat resistance and absorption. The intensity of methane/coal dust deflagration was weakened with the increasing of coal ash mass fraction. In addition, the inhibition mechanisms of coal ash on coal dust deflagration were summarized based on the material analysis of the deflagration residues.

Alkali-activated binders based on the coarse fraction of municipal solid waste incineration bottom ash

The potential of the least polluted fraction (from 8 to 30mm) of municipal solid waste incineration (MSWI) weathered bottom ash (WBA) as an alkali-activated cement precursor was evaluated. Alkali-activated WBA binders (AA-WBA) formulations were prepared through alkali-activation of WBA as sole precursor. Sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) mixtures with different pH's were used as alkali-activator solution. The effect of alkali-activator solution pH on the final properties was assessed. Results showed the hydrolytic stability of all formulations. The selective chemical extractions and physicochemical characterisation revealed the formation of the C–S–H, C–A–S–H, and (N,C)–A–S–H gels. The promising compressive strength results demonstrated the potential of AA-WBA binders. The increase of pH in the alkali-activated solution promotes the formation of gel reaction products and enhance mechanical properties. This investigation promotes the green cements manufacturing and the use of secondary resources to reduce the impact of natural resources extraction used for the ordinary Portland cement (OPC) production.