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Bioenergy, as a form of regenerable power, is an excellent alternative to ensure a clean and healthy environment and at the same time, to preserve natural energy resources that are constantly decreasing. Due to their biological origin, biofuels used in combustion processes contribute to the releasing of non-polluting gases in ambience with low percentages of CO2, CO, NOx, etc. The paper presents the project of an oxy-biological fuel burner using glycerin and ethanol as biofuels, suitable for industrial thermal processes at high temperature. The project was based on the own outcomes previously obtained in 2022, adding new contributions to improve the combustion process. Keeping the heat power of the burner at 60 kW, the glycerin and ethanol flows were adopted at 10 and 1.11 kg·h-1, i.e. a mass ratio of 9.0 than 8.1 used in the previous experiment. Residual gas composition measured under these conditions showed under 0.05 vol. % CO2, 0 vol. % CO as well as below 183 mg·m3 N-1 NO and under 200 mg·m3N-1 NO2.

Geopolymer froth with excellent physio-mechanical, heat, and morphological features was made from a mix including fly ash and metallurgical slag as alumina-silicate industrial by-products. Using the metallurgical slag and montmorillonite as a nanomaterial constituted the composition novelty of starting mixture as well as the use as surfactant of a rarely applied material (sunflower oil) in making process of geopolymer froth were originality elements. Results were appreciable, the compression resistance reaching 6.7 at the final curing process and 4.9 MPa at early age and flexure resistance registering 3.3 MPa and 3.0 MPa at the final curing process and early age, respectively. The new cellular product is adequate for applications in construction as a lightweight insulating material, having better features by comparing with the traditional lightweight porous concrete.

The experiment described in this paper is part of the series of worldwide investigation of the influence of different types of alumina-silicate waste on properties of geopolymer concrete. The work originality consists in the choice of recycled post-consumer green packaging bottle as a partial substitute for fly ash, unlike recent results known from the literature of the use of brown glass waste powder or in a mixture of coloured glass. The results showed that the replacement of 18 % of the initial fly ash content is an optimal solution to increase the compression and flexural strength of the geopolymer concrete both after 7 days of storage and after 28 days. In this case, the compression resistance values ​​reached 34.8 and 46.0 MPa, respectively and the flexural resistance values ​​were 5.9 and 8.9 MPa, respectively. Further increasing the proportion of green glass up to 30 % contributed to a surplus of concrete strength, but to a very small extent, reaching a maximum of 34.9 and 47.0 MPa and respectively, 6.0 and 9.1 MPa.

Simultaneous geopolymerization and densification of geopolymeric products is a viable process by cold sintering of residual alumina-silicate. The procedure peculiarity is the axial pressing of the powder previously produced by the usual geopolymerization. Sodium metasilicate nonahydrate is the type of alkaline activator used in the experiment, which does not require the addition of water and does not lead to the formation of a suspension. The geopolymer manufacturing process involved a mixture composed of coal ash, ground metallurgical slag, nano-silica, and sodium metasilicate nonahydrate, the pressing force of the powder being between 60-90 MPa. The compression resistance of the geopolymer reached a maximum of 51.75 MPa.

A new and original dosing of alumina-silicate wastes in preparing mixture of the geopolymeric material is presented in this paper. Unlike the usual preponderant utilization of fly ash and ground blast furnace slag, the article adopted a major proportion of concrete waste from building demolition compared to the other two mentioned components, aiming at obtaining high strength geopolymers. The result of applying this new dosing in the material mixture activated with alkaline solution was increasing the compression and flexural resistance of the geopolymer, especially at earl age of curing (7 days). The experiment showed that by mixing 310-470 kg·m-3 of concrete waste from demolition, 230-254 kg·m-3 of fly ash, 102-120 kg·m-3 of blast furnace slag, and 4 kg·m-3 of silica fume, the best performing mechanical characteristics of the geopolymer can be obtained. The optimal values ​​of denseness were between 1.64-2.04 g·cm-3 and those of heat conductance were between 0.218-0.306 W·m-1·K-1.

A procedure for making a wooden heat-insulating product for construction applications through lignin removing is presented in this paper. The non-conventional procedure is almost similar to that known and used in the pulp and paper industry, but the technological purpose is clearly different. The type of tree wood chosen by authors (Romanian spruce wood) is a novelty compared to the rather large list of tree species tested so far and represents the originality of the work. The liquid alkaline environment was constituted of NaOH, Ca(OH)2, and distilled water and this has activated the spruce wood waste. By removing lignin from the wood structure, heat conductance of the wooden material decreased by comparison with conductance of the same type of non-treated wood. The heat treatment temperature into an electric oven was 95 ℃ for 8 hours. The results showed the possibility to obtain a product with denseness value of 0.14 g·cm-3 and heat conductance of 0.030 W·m-1·K-1, i.e. very good insulation properties. Analyzing the material quality, this was almost identical to high-performance wooden materials.

The comparative analysis of the cellular glass products manufactured by the non-conventional microwave heating method compared to those made on a large scale by conventional methods is presented in this paper. Applying the non-conventional method was carried out in recent years by authors of the current article. Four different testing versions were selected by the composition of the material mixture including the expanding agent as well as the operational parameters. SiC, CaCO3, and Si3N4 separately constituted the expanding agents used in the analyzed experiments. Also, fly ash, red iron oxide, borax, and MnO2 were other additional materials included into the mixture, also separately. The specific energy consumption of producing processes were very low under the conditions of using a microwave equipment at very small-scale (0.8 kW), there being the possibility of improving this parameter by up to 25 % by applying the method on an industrial-scale.

Self-compacting concrete, as a performing material whose casting and compacting can be made without applying the vibration technique, due to the flowability properties that allow it to flow by its own mass, was produced and tested in several versions of the material composition. Flowability gives high structural homogeneity and allows fast concrete pouring rate in a shorter time. During the experiment, four experimental versions were tested successively using coal ash, metallurgical slag, limestone dust as well as a combination of fly ash-slag as cementitious materials, that partially replaced Portland cement. Also, a water-reducing additive (polycarboxylate ether) was added in different ratios. Aggregates were chosen at low particle size (fine sand below 2 mm and granite gravel less than 12 mm). Mixing the materials together with the working water led to obtaining the paste with excellent flowability properties. The consolidated concrete had compactness and homogeneity and the mechanical characteristics were comparable to those of traditionally made concrete. Except for the remarkable flow characteristics of the paste, in this experiment it was proven that the compression strength of self-compacting concrete can reach very high values (after 28 days) of up to 60.4 MPa.

Peculiarities of the modern cellular concrete manufacturing technique were borrowed in the expanding glass technique at ambient temperature presented in the work. Using aluminum dust in calcium hydroxide solution and adding carboxymethyl cellulose (CMC) as a froth fixer, cellular glass specimens with excellent insulating properties with minimal energy consumption could be experimentally obtained, as an alternative solution to conventional methods industrially used. The tests presented in this article intend to improve the mechanical resistance of the cellular product under the conditions of preserving existing insulating properties by adding to the starting mixture a very effective ultrafine powder (silica fume) contributing to the increase of strength and durability. Completing the manufacturing recipe with silica fume is the originality element compared to the previously applied solutions. The results confirmed the effectiveness of the new method, the compressive strength increasing up to 4.7 MPa under conditions of density below 0.35 g·cm-3 and heat conductivity below 0.079 W·m-1·K-1.

High-strength cement-free geopolymer concrete with 62.9 MPa (after 28 curing days) was experimentally produced from blast furnace slag, recycled concrete, and metakaolin as alumina-silicate binders as well as silica fume as silica-rich ultra-fine powder. Combining slag with metakaolin and silica fume allowed to increase its proportion up to 58.1 wt. %, without affecting shrinkage and hardness. Residual concrete from demolition was also used for making the geopolymer concrete as coarse aggregate as well as alumina-silicate binder together with fly ash, but not with granulated slag, metakaolin, and silica fume, this constituting the paper originality.

Geopolymer foam with thermal insulation properties was made by foaming the alumino-silicate mixture composed of fly ash and clay brick waste activated with alkaline activator (water glass and sodium hydroxide in aqueous solution). Other mixture components were expanded perlite as siliceous additive, usual fine aggregate (quartz sand), and less frequently used surfactant (olive oil). The main characteristics of the geopolymer foam were: low density, low thermal conductivity, and relatively high compressive strength. The residual materials contributed to low costs and the complete replacement of ordinary cement led to the significant reduction of CO2 emissions.

A technique for manufacturing wood heat-insulating material for construction (known as wood delignification) without seriously affecting the cellulosic structure was inspired by the practices of the pulp and paper industry and adapted to the mentioned purpose. Among the numerous known methods of chemical treatment of wood for removing the lignin in the paper industry, the use of the suspension generated by mixing of NaOH, Ca(OH)2, and distilled water at 260 ℃ in an electric oven was adopted. For the first time, oak wood (recycled in the form of sawdust) was chosen as the basic raw material in the wood delignification process due to its large availability in Romania's climatic conditions. Using 58 % oak wood, 23.3 % NaOH, 16.7 % Ca(OH)2, and water addition, the best product had very low values of density (0,024 g·cm-3) and heat conductivity (0.031 W·m-1·K-1) as well as an acceptable value of compression resistance (0.9 MPa) for construction applications.

The research trend in the last years on early-age carbonation of calcium silicate hydrate, main component phase of Portland cement, in association with the process of permanent storage of CO2 in carbonates, reducing its emissions in the atmosphere, was the objective of ongoing work. Using sodium bicarbonate (NaHCO3) in the mixture of cementitious materials, partially replacing the cement (between 7-21 %), curing the fresh concrete was made in an early-age period. Very high value of compressive strength (43.1 MPa) was obtained very quickly being measured in the first stage of investigating the sample characteristics (after 8 hours), the reference sample reaching 30.8 MPa after 7 days and 43.3 MPa after 28 days.

Copyright of Romanian Journal of Civil Engineering / Revista Română de Inginerie Civilă is the property of Matrix Rom and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Alumino-silicate wastes frequently used in the manufacturing process of geopolymer composites (fly ash and blast furnace slag) were mixed with alumino-silicate wastes non-used previously in this process (clay brick waste and glassware waste). The mixture activation with an alkaline activator based on NaOH 8M and Na2SiO3 aqueous solution that facilitates the geopolymerization reaction developing contributed to the conversion of waste into geopolymer composite, a new type of cheap and ecological materials with mechanical and physical properties suitable for the building sector. The optimal characteristics of specimens were: density of 2042 kg·m-3, apparent porosity of 19.6 %, compression strength of 53.7 MPa, and water absorption of 6.9 vol. %.

High-strength geopolymer composite, a new type of construction material, based on granulated blast furnace slag and coal fly ash reinforced with PET fibres obtained by recycling and processing PET bottles was experimentally made. According to Davidovits' invention, an aqueous solution of sodium hydroxide and sodium silicate representing the alkaline activator was the basic element of the process favouring the development of the geopolymerization reaction, which involves the residual alumino-silicate materials (blast furnace slag and fly ash). The final curing process of the composite in the state of slurry poured into molds constituted the originality of the work by alternating the curing at room temperature for 20 hours with curing by maintaining the material at 75 ºC for 10 hours and then continuing the curing process at room temperature for 7 and 28 days respectively. The composite geopolymer had remarkable mechanical properties (compression strength of 60.1 MPa and flexural strength of 11.5 MPa) corresponding to the maximum proportion of PET fibres of 2.3 wt. % and final curing process time of 28 days. The composite made from residual materials is suitable for its use in ecological production conditions and with extremely low energy consumption.

A nonconventional material with remarkable thermal and acoustic insulation properties from aerogels category was experimentally made. Produced from a recycled commercial waste (polyethylene terephthalate-PET) and an industrial by-product (fly ash) as well as a biomaterial (psyllium husk) used for the first time as a binder by mixing with water, the aerogel was subjected to a freeze-drying process. The determination of the product characteristics highlighted extremely low densities (0.022-0.041 g· cm-3), very low thermal conductivities (0.035-0.037 W·m-1·K-1), very high porosities (97.8-98.5 %), mechanical properties superior to those of an unreinforced gel (compression strength of 9.5-16.4 kPa and Young's modulus of 4.15-18.93 kPa), and excellent noise absorption properties (noise reduction coefficient of 0.30-0.33). The manufacturing process of this inexpensive product allows for a clean environment.

Experimentally, fine porosity-aerated concrete was made using the technique of corrosion the aluminum powder as a foaming agent in Ca(OH)2 solution. The powder (below 10 μm) was obtained from recycled waste, melted by microwave irradiation and atomized by the contact with gaseous nitrogen jets in an original facility designed by authors. The making recipe of concrete is based on calcined gypsum as the main binding agent substituting the pollutant and non-economic cement, fly ash from industrial coal burning, perlite, silica fume, hydrated lime and distilled water. Aerated concrete with excellent thermal insulation properties (density of 601 kg/m3, heat conductivity of 0.114 W/mK, and porosity of 75.2 %) was obtained. The compression strength was increased to 3.9 MPa by curing process with 0.3 bars-steam and 75 ºC for 4 hours and holding further 8 hours inside a sealed room heated to 80 ºC. The product belongs to the new generation of building materials made without CO2 emission and with low energy consumption.

New geopolymer concrete with high mechanical strength - 58.9 MPa after 28 days of curing - was experimentally made under environmental friendly and economic conditions. The high-strength-geopolymer is baed on coal fly ash and building concrete waste as geopolymer materials suitable for completely substituting the cement in concrete structure. The alumino-silicate geopolymer materials with binder role were activated in liquid alkaline medium (sodium silicate and sodium hydroxide) for facilitating the polymerization reaction that turns the alumino-silicate wastes into geopolymer concrete. The use for the first time in this experiment of recycled building concrete waste from demolition is the work originality.

Super-aluminous refractory concrete (over 94 % Al2O3) with low dosage of cement (9 %) was made, its physical, thermal, and mechanical characteristics being considered suitable for the intermediate layer of a steel casting ladle: porosity of 29.31 %, the apparent density of 2.32 g·cm-3 thermal conductivity of 1.45 W·m-1·K-1, and compressive strength of 34.8 MPa (after heat treatment at 1500 ºC). The aim of the research was achieving a super-aluminous concrete with low-cement dosage, which would have acceptable thermal insulation properties, so that the heat loss through this refractory lining layer would be significantly reduced compared to the reference situation.

The innovative method of geopolymer concrete making by completely replacing the cement with coal fly ash and granulated blast furnace slag (residual aluminosilicate materials) was experimentally applied and presented in the paper. Compared to other experiments described in literature, the work originality is the significant increasing of slag ratio (15-25 %) in the aluminosilicate binder, to increase the compressive strength despite the decrease in workability. Sodium silicate and aqueous solution of sodium hydroxide were used as activators. River sand (fine aggregate) and natural gravel (coarse aggregate) completed the concrete making recipe. The compressive strength had increasing values (above 51 MPa) with the increase of slag ratio, density decreased up to 2290 kg/m3, fresh concrete workability according to standard for concrete slump test decreased from 70 mm up to 45 mm, while water absorption was relatively constant between 0.78-0.80 vol. %. The making variant adopted as optimal was that with 80 % fly ash and 20 % slag having the compressive strength of 53.3 MPa, density of 2298 kg/m3 and fresh concrete workability of 58 mm (i.e. a medium workability).

Carbon foam, an extremely attractive new material type for important fields of application, with low density (0.28 g cm-3), low thermal conductivity (0.110 W m-1 K-1), relatively high compressive strength (3.5 MPa), high electrical conductivity (29.8 S m-1), and very high electromagnetic shielding effectiveness (46 dB) was experimentally made using recycled wood biomass from industrial wood processing and aqueous solution of sucrose. The carbonization was performed by heating at 750 ºC through microwave irradiation technique, the pressed and dried material in the intermediate state being introduced into a SiC crucible with a lid, thermally protected with ceramic fiber, without inert medium. The specific energy consumption was very low (0.785 kWh/kg), unlike the high energy consumption of the usually carbonization stages. The optimal carbon foam specimen was considered suitable for the special application fields (military, aeronautics, construction, transport).

Alumina ceramics were obtained from three different alumina sources, A1–A3, with various rare-earth dopants (La2O3–La, Nd2O3–Nd, and Y2O3–Y), concentration levels (500 and 1000 ppm) and synthesizing routes (1500 °C, 1815 °C and cold plasma-P). Absorption (A) and density (ρ in text, rho in images) were measured, resulting in a complex, multivariate database. Principal Component Analysis (PCA) was run with the aim of deducing relationships between variables (alumina source, dopant level, thermal processing route, A and ρ), observations, and between variables and observations. A total of 206 Scanning Electron Microscopy (SEM) micrographs were recorded at various scales and the corresponding images were processed to quantify the microstructural features. Two techniques of edge detection were used; Fractal Dimension (FD) was calculated for each micrograph and results were compared. Various scales of the micrographs prevented us from using any other approach, such as simply measuring the grains or obtaining shape parameters. The initial database was extended by including FDs and PCA was run again. We found that plasma processing is positively correlated to A and negatively correlated to both temperature (T) and ρ; La ceramics have an opposite behavior to Y and Nd ceramics. FD successfully explained observations being correlated, mainly, to Y, Nd and, to a lesser extent, to La. FD proved that it is a reliable and simple approach to quantifying microstructural features when comparing highly different, noisy micrographs.

The renewable energy that also includes bioenergy represents the viable alternative of improving the environment quality and at the same time, protecting the natural fossil fuel reserves globally diminished in the last period. Having biological origins, the burning of biofuels for energy purposes is a non-conventional process accepted on the global scale as a solution to replace polluting fossil fuels. The work aims to test the conditions of using glycerol together with ethanol as biofuels in an original oxy-fuel combustion process. All oxy-liquid biofuel burners designed and experimentally tested in the world are intended for internal combustion engines, while the burner presented in this paper is designed for heating boilers and furnaces, the difference in the constructive and functional principle determining the paper originality. The experiment carried out on the burners testing stand in the Metallurgical Research Institute of Bucharest allowed establishing the optimal characteristics of the process for the nominal heat power of 60 kW under the conditions of obtaining a stable flame, with high temperature (1781-1846 ºC) and moderate emissions of carbon dioxide (below 0.13 vol. %) and nitrogen oxides (152-210 mg/m3N).

Copyright of Romanian Journal of Civil Engineering / Revista Română de Inginerie Civilă is the property of Matrix Rom and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A procedure for making a wooden heat-insulating product for construction applications through lignin removing is presented in this paper. The non-conventional procedure is almost similar to that known and used in the pulp and paper industry, but the technological purpose is clearly different. The type of tree wood chosen by authors (Romanian spruce wood) is a novelty compared to the rather large list of tree species tested so far and represents the originality of the work. The liquid alkaline environment was constituted of NaOH, Ca(OH)2, and distilled water and this has activated the spruce wood waste. By removing lignin from the wood structure, heat conductance of the wooden material decreased by comparison with conductance of the same type of non-treated wood. The heat treatment temperature into an electric oven was 95 °C for 8 hours. The results showed the possibility to obtain a product with denseness value of 0.14 g⋅cm-3 and heat conductance of 0.030 W⋅m-1⋅K-1, i.e. very good insulation properties. Analyzing the material quality, this was almost identical to high-performance wooden materials. [ABSTRACT FROM AUTHOR]

A new and original dosing of alumina-silicate wastes in preparing mixture of the geopolymeric material is presented in this paper. Unlike the usual preponderant utilization of fly ash and ground blast furnace slag, the article adopted a major proportion of concrete waste from building demolition compared to the other two mentioned components, aiming at obtaining high strength geopolymers. The result of applying this new dosing in the material mixture activated with alkaline solution was increasing the compression and flexural resistance of the geopolymer, especially at earl age of curing (7 days). The experiment showed that by mixing 310-470 kg⋅m-3 of concrete waste from demolition, 230-254 kg⋅m-3 of fly ash, 102-120 kg⋅m-3 of blast furnace slag, and 4 kg⋅m-3 of silica fume, the best performing mechanical characteristics of the geopolymer can be obtained. The optimal values of denseness were between 1.64-2.04 g⋅cm-3 and those of heat conductance were between 0.218-0.306 W⋅m-1⋅K-1. [ABSTRACT FROM AUTHOR]

The paper is a contribution of authors to the knowledge enrichment on the recent development of the new manufacturing technique of wood foam for packaging excluding plastics in its preparation mixture. Given that there is only one industrial manufacturer in the world of this type of wood foam with excellent heat-insulating properties, the current work presents an original method of its production using raw materials different from those applied in the industrial manufacturing recipe. Oak and beech wood waste, bentonite clay as a nanomaterial, calcium lignosulfonate as a surfactant, and distilled water were materials chosen by authors. The features of the new optimal product were density of 0.06 g·cm-3, heat conductivity of 0.027 W·m-1·K-1, porosity of 94.1 %, and compression strength of 985 kPa, being approximately similar by comparison with industrial products. [ABSTRACT FROM AUTHOR]

The comparative analysis of the cellular glass products manufactured by the non-conventional microwave heating method compared to those made on a large scale by conventional methods is presented in this paper. Applying the non-conventional method was carried out in recent years by authors of the current article. Four different testing versions were selected by the composition of the material mixture including the expanding agent as well as the operational parameters. SiC, CaCO3, and Si3N4 separately constituted the expanding agents used in the analyzed experiments. Also, fly ash, red iron oxide, borax, and MnO2 were other additional materials included into the mixture, also separately. The specific energy consumption of producing processes were very low under the conditions of using a microwave equipment at very small-scale (0.8 kW), there being the possibility of improving this parameter by up to 25 % by applying the method on an industrial-scale. [ABSTRACT FROM AUTHOR]

Peculiarities of the modern cellular concrete manufacturing technique were borrowed in the expanding glass technique at ambient temperature presented in the work. Using aluminum dust in calcium hydroxide solution and adding carboxymethyl cellulose (CMC) as a froth fixer, cellular glass specimens with excellent insulating properties with minimal energy consumption could be experimentally obtained, as an alternative solution to conventional methods industrially used. The tests presented in this article intend to improve the mechanical resistance of the cellular product under the conditions of preserving existing insulating properties by adding to the starting mixture a very effective ultrafine powder (silica fume) contributing to the increase of strength and durability. Completing the manufacturing recipe with silica fume is the originality element compared to the previously applied solutions. The results confirmed the effectiveness of the new method, the compressive strength increasing up to 4.7 MPa under conditions of density below 0.35 g·cm-3 and heat conductivity below 0.079 W·m-1 ·K-1 . [ABSTRACT FROM AUTHOR]

High-strength cement-free geopolymer concrete with 62.9 MPa (after 28 curing days) was experimentally produced from blast furnace slag, recycled concrete, and metakaolin as alumina-silicate binders as well as silica fume as silica-rich ultra-fine powder. Combining slag with metakaolin and silica fume allowed to increase its proportion up to 58.1 wt. %, without affecting shrinkage and hardness. Residual concrete from demolition was also used for making the geopolymer concrete as coarse aggregate as well as alumina-silicate binder together with fly ash, but not with granulated slag, metakaolin, and silica fume, this constituting the paper originality. [ABSTRACT FROM AUTHOR]

Self-compacting concrete, as a performing material whose casting and compacting can be made without applying the vibration technique, due to the flowability properties that allow it to flow by its own mass, was produced and tested in several versions of the material composition. Flowability gives high structural homogeneity and allows fast concrete pouring rate in a shorter time. During the experiment, four experimental versions were tested successively using coal ash, metallurgical slag, limestone dust as well as a combination of fly ash-slag as cementitious materials, that partially replaced Portland cement. Also, a water-reducing additive (polycarboxylate ether) was added in different ratios. Aggregates were chosen at low particle size (fine sand below 2 mm and granite gravel less than 12 mm). Mixing the materials together with the working water led to obtaining the paste with excellent flowability properties. The consolidated concrete had compactness and homogeneity and the mechanical characteristics were comparable to those of traditionally made concrete. Except for the remarkable flow characteristics of the paste, in this experiment it was proven that the compression strength of self-compacting concrete can reach very high values (after 28 days) of up to 60.4 MPa. [ABSTRACT FROM AUTHOR]

Food waste, particularly animal-derived waste, presents a significant challenge globally, prompting the need for sustainable management strategies. In 2022, the amount of food waste per capita reached 131 kg/capita in the EU (European Union), which is why the search for environmentally friendly ways to manage food waste through thermochemical conversion processes has gained momentum in recent years. Animal-derived waste is a good source of organic matter (proteins, lipids, and polysaccharides) and mineral compounds (calcium phosphate, mostly hydroxyapatite). This composition makes animal-derived waste valuable for the extraction of chemical compounds, such as hydroxyapatite (HAp), which constitutes up to 70 wt% of animal bones; keratin; collagen; and hyaluronic acid (HA), to produce pharmaceutical, medical, or industrial by-products. The thermochemical conversion of chicken bones through pyrolysis and gasification creates a new opportunity to valorize this type of waste by reintroducing valuable by-products into the economy and thus achieving sustainable waste management objectives. The results of this study showcase the multiple applications of the pyrolysis of chicken bone waste products (as adsorbents in aqueous mediums, catalysts, fertilizers, and biomedical applications) and the necessity of a better exploration of the gasification process of chicken bone waste. Therefore, this study explores the properties of animal-derived waste and discusses the pyrolysis and gasification of chicken bone waste, the influence of process conditions on product yields, and the catalytic enhancement of these thermochemical processes. [ABSTRACT FROM AUTHOR]

Copyright of Romanian Journal of Civil Engineering / Revista Română de Inginerie Civilă is the property of Matrix Rom and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Romanian Journal of Civil Engineering / Revista Română de Inginerie Civilă is the property of Matrix Rom and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A technique for manufacturing wood heat-insulating material for construction (known as wood delignification) without seriously affecting the cellulosic structure was inspired by the practices of the pulp and paper industry and adapted to the mentioned purpose. Among the numerous known methods of chemical treatment of wood for removing the lignin in the paper industry, the use of the suspension generated by mixing of NaOH, Ca(OH)2, and distilled water at 260 ℃ in an electric oven was adopted. For the first time, oak wood (recycled in the form of sawdust) was chosen as the basic raw material in the wood delignification process due to its large availability in Romania's climatic conditions. Using 58 % oak wood, 23.3 % NaOH, 16.7 % Ca(OH)2, and water addition, the best product had very low values of density (0,024 g·cm-3) and heat conductivity (0.031 W·m-1·K-1) as well as an acceptable value of compression resistance (0.9 MPa) for construction applications. [ABSTRACT FROM AUTHOR]

This article aims at presenting the impact that the New Romanian Shakespeare edition launched in 2010 by George Volceanov has had on the literati and theatres so far. It is, therefore, a stocktaking exercise and its main goal is to provide Shakespeare scholars with an initial data base for further investigation of theatrical productions which use the new translation as significant moments in the history of Shakespeare’s reception in Romania and, on the other hand, to occasion some reflective remarks on the six years of the series now at its tenth volume and 26 plays plus the Sonnets.

Alumina ceramics were obtained from three different alumina sources, A1–A3, with various rare-earth dopants (La2O3–La, Nd2O3–Nd, and Y2O3–Y), concentration levels (500 and 1000 ppm) and synthesizing routes (1500 °C, 1815 °C and cold plasma-P). Absorption (A) and density (ρ in text, rho in images) were measured, resulting in a complex, multivariate database. Principal Component Analysis (PCA) was run with the aim of deducing relationships between variables (alumina source, dopant level, thermal processing route, A and ρ), observations, and between variables and observations. A total of 206 Scanning Electron Microscopy (SEM) micrographs were recorded at various scales and the corresponding images were processed to quantify the microstructural features. Two techniques of edge detection were used; Fractal Dimension (FD) was calculated for each micrograph and results were compared. Various scales of the micrographs prevented us from using any other approach, such as simply measuring the grains or obtaining shape parameters. The initial database was extended by including FDs and PCA was run again. We found that plasma processing is positively correlated to A and negatively correlated to both temperature (T) and ρ; La ceramics have an opposite behavior to Y and Nd ceramics. FD successfully explained observations being correlated, mainly, to Y, Nd and, to a lesser extent, to La. FD proved that it is a reliable and simple approach to quantifying microstructural features when comparing highly different, noisy micrographs. [ABSTRACT FROM AUTHOR]