Non-conventional Materials Research Articles

Development of the High-purity Aluminium Oxide Powder Producing Technology on the Ural Region Raw Materials Basis


 
 
 This article considers an effective way of complex alumina-containing materials of natural or technogenic origin processing with obtaining a whole complex of raw materials: alkali-free highly active aluminum hydroxide, iron hydroxide, aluminum hydroxide, etc. In laboratory conditions the alumina raw materials behavior in the thickening, washing, filtration processes were checked. The optimal parameters of the processes were selected as a result of conducted research.
 Keywords: non-conventional alumina raw materials, technogenic materials, hydrochemical processing, ammonium hydrosulfate, environmental friendliness, efficiency
 
 

Production of biochars derived from sewage sludge and orange peels

The increasing accumulation of waste in the environment has several environmental and public health impacts. In contrast, the circular economy emerges as a model that seeks the return of waste to the production chain. An alternative for the reinsertion of these materials to the production cycle is their conversion into biochar by the pyrolysis process. Thus, this study aims to produce, perform the initial characterization and compare biochars obtained from two different matrices: sludge from sewage treatment plants and orange peels. The sludge samples were pyrolyzed at 450 °C (BL450) and 650 °C (BL650). While the orange peel biochars were produced at 400 °C (BC400) and 600 °C (BC600). Yields were determined and analyzes of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were also performed. The yields obtained were 32% (BC400), 28% (BC600), 46% (BL450) and 38% (BL650). The presence of pores was identified in the BC400 and BC600 SEM micrographs. However, for the BL450 and the BL650 samples, heterogeneous and asymmetric surfaces were observed. From the EDX analysis the absence of trace metals and the presence of compounds potentially beneficial to the soil and plants were found, which can act as binders in the adsorption process. In addition, due to their mostly carbonaceous composition, biochars are resistant to decomposition and can contribute to the carbon sequestration process. The yields obtained indicate a reduction of the mass of waste, which can be advantageous for handling and transportation. As a result, the production of biochar from non-conventional materials, such as sewage sludge and orange peels, can be seen as an attractive alternative for waste management, since it assists the reintroduction of these materials in the production chain, according to the concept of circular economy.

The beauty of contemporary façade. Tradition, technique, technology

The article focuses on the contemporary diversity of creating facades of public utility facilities. Approaches, in which trends of the tradition of place, as well as technique and technology, have a significant influence on the architectural image and the beauty of the façade, are analysed and arranged. The elevation of the building plays an important functional and aesthetic role. It protects the interior against environmental conditions and, at the same time, is the characteristic feature of the building. The necessity of prestige, being distinguished in its surroundings and/or appearing in the consciousness of residents make the architects seek original, innovative and often beautiful solutions. The searches are multi-layered and depend on the architect’s conception. They become visible when the relation between the architecture of the building and the urban context is considered. Because of the geometry of the building and the material which is used in the façade influence, the perception of the building in urban surroundings, buildings of rectilinear geometry in urban space were analysed. The nonconventional materials implemented on the elevation or used in a non-conventional form may be grouped in the following way:• Traditionalism of the material. Due to the technique and/or technology, the formal image of the elevation changes, yet remaining the matter which originates from the historic record of the implemented material. For example, ceramics used in contemporary architecture do not always resemble classical brick, however, its formal distinctness does not change the essence of materiality.• Transparency and transience of the image. In contemporary searches, it leads both to the impression of levity and/or to the creation of an illusion, weightlessness of the building and creation of the impression of unity of the architecture with the surrounding landscape.• Multilayering of contemporary shielding wall helps in introducing ‘additional’ functions into the external wall. Except for the basic function, the protection of the interior against surrounding conditions, multimedia, transparency, and energy-efficiency is also implemented.The above relationships are described based on examples of the architecture of contemporary Poland. Krzysztof Kieślowski Film School at the University of Silesia (arch. Baas arquitectura, Grupa 5 Architekci, Maleccy Biuro Projektowe, 2017), fitted in the historic frontage shows the new form of traditional material-brick. The impression of transparency of the building is shown on the complex, glass elevation of The Polin Museum in Warsaw (arch. Lahdelma& Mahlamäki, 2013) standing among residential blocks. In contrast, the multimedia façade of the Centre for the Meeting of Cultures in Lublin (arch. Bolesław Stelmach, Biuro Architectoniczne Stelmach i Partnerzy, 2015) relates to the function of the building and the space of the urban square where it is located. The suggested approach shows that architectural innovation is manifested by the search for solutions to contemporary multi-layered materiality of shielding walls

Vapor-liquid equilibria and cohesive r-4 interactions.

The role of cohesive r-4 interactions on the existence of a vapor phase and the formation of vapor-liquid equilibria is investigated by performing molecular simulations for the n-4 potential. The cohesive r-4 interactions delay the emergence of a vapor phase until very high temperatures. The critical temperature is up to 5 times higher than normal fluids, as represented by the Lennard-Jones potential. The greatest overall influence on vapor-liquid equilibria is observed for the 5-4 potential, which is the lowest repulsive limit of the potential. Increasing n initially mitigates the influence of r-4 interactions, but the moderating influence declines for n > 12. A relationship is reported between the critical temperature and the Boyle temperature, which allows the critical temperature to be determined for a given n value. The n-4 potential could provide valuable insight into the behavior of non-conventional materials with both very low vapor pressures at elevated temperatures and highly dipolar interactions.

Pole identification method to extract the equivalent fluid characteristics of general sound-absorbing materials

A method is presented to characterize general sound-absorbing materials through a pole-based identification of the equivalent fluid. This is accomplished by 1) determining the extended equivalent fluid of the material sample through the transfer function method (TFM), 2) identification of the acoustic response of the material through the poles of the extended effective density and compressibility, and 3) build the effective density and compressibility from the poles associated to the local acoustic response. Real pole pairs describe a dissipative medium (or equivalently an over-damped resonating medium), which is the natural behavior of rigid-frame porous materials, while complex-conjugate pole pairs describe a locally-resonant medium typical of metamaterials. Complex-conjugate poles associated to elastic resonances of the sample are discarded. We test the method for several non-conventional porous materials. In general, a better fit to the measured surface impedance is obtained than with an acoustics-based identification to the Johnson-Champoux-Allard-Pride-Lafarge model (JCAPL), and the method appears also to be robust to errors of the TFM.

Impacts of nonconventional construction materials on concrete strength development: case studies

Sustainable building technology is a new approach adopted in built environment, which is focused on significantly reducing impact of the construction industry on the environment. Moreover, the world is largely driving development of sustainable and smart products to mitigate global pollution issues. In this study, assessment of the impacts of using alternative constituents such as crumb rubber, coconut shell, recycled aggregate, GGBS, human hair, banana fiber, industrial sludge, saw dust, rice husk, wood waste, textile, copper slag, textile, glass powder, plastic etc., on concrete strength development using case studies has been performed. The paper explores the research work carried out towards sustainable approach in replacement of basic composition of concrete. It focuses on various waste materials used as a substitute options in concrete and characteristic strength development along with potential challenges. Leading researches relating to sustainable materials were also explored. The results show that the alternative aggregates, mostly with minimally usage of about 20% increased the compressive strength properties of concrete. Usage of fibres to about increased the flexural property of concrete and the replacement of waste sludge didn’t show appreciable increased of compressive strength.

The Effect of Lightweight Expanded Clay Aggregate on the Mitigation of Liquefaction in Shaking Table

Non-conventional materials are often applied to dissipate the energy of dynamic loads and mitigate liquefaction. In this study, the effect of Lightweight Expanded Clay Aggregate (LECA) on the mitigation of liquefaction was examined using shaking table tests. LECA, a common lightweight material, was added to saturated sand in a range of 0–20% to study the variation of excess pore water pressure (EPWP) generation, as well as the acceleration response of the soil. Based on the obtained results, the addition of 5% and 10% LECA to saturated sand resulted in a significant decrease in the generation of EPWP, while higher LECA content led to an increase in the generation of EPWP. The mechanisms behind such behaviors contradict the effects of increasing the damping of the soil mixture and reducing the effective initial stress as a function of overall mixture density. Adding 5 and 10% LECA reduces EPWP because aggregates accelerate the dissipation of EPWP during and after vibration. As the percentage of LECA increases by 15% and 20%, excess pore pressure ratio increases. The cause of this may be the reduction of effective initial stress leading to reduced soil density in higher-LECA contents. 10% LECA is presented as the threshold for changing the liquefaction behavior of sand-LECA mixtures. This study concludes that adding LECA to sand samples increases the rate of dissipation of EPWP, but also leads to a significant decrease in initial effective stress.

Physicochemical and functional properties of mangalô bean (Lablab purpureus L.) starch

The rising search for new starch sources stimulated the interest in several non-conventional raw materials lately. In the present study, starch from unripe (green) Lablab purpureus L. bean was isolated and characterized for morphological, pasting, thermal, and physicochemical properties in order to determine its potential end-use. The chemical composition of the mangalô bean starch was 9.37% of moisture, 0.18% of ashes, 0.09% of lipids, 0.007% of phosphorus, and 45.32% of apparent amylose content. X-ray diffraction confirmed the C-type crystallinity pattern of this starch, typical of leguminous plants. Thermogravimetric-differential thermal analysis indicated that the isolated starch withstood high temperatures. The starch displayed high tendency to retrogradation and resistance to gelatinization. The high amylose content and the water absorption capacity suggest the use of this starch in the production of biodegradable films, preparation of syrups with high glycose content, as well as its incorporation into cooked and canned products.

Behavior of Copper Slag Admixed Concrete in Acidic Environment

Non-conventional building materials are in huge demand these days because of rapid urbanization and huge cost associated with conventional building materials. Sand is majorly used fine aggregate in the preparation of concrete, however heavy depletion of river beds and rising cost of sand have made the builders and construction industry to think about alternative form of fine aggregate. Many alternatives like industrial wastes, different types of slags, stone dust and agro wastes etc. have been tried to fully or partially replace river sand in preparation of concrete and the results have been encouraging. Out of the non-conventional materials, copper slag is one such type which has a capable future to be used as a fine aggregate in preparation of concrete. The initial strength studies carried out have shown that the optimum percentage of copper slag as a partial replacement of sand in concrete is 40%. To ascertain any material as a building material it is highly important that along with the strength aspects of the material the durability characteristics also verified. So as part of durability studies of copper slag concrete, an attempt has been made here to examine the impact of acid attack on copper slag concrete and the effects have been compared with that of normal concrete. M30 grade of concrete has been used for this experimental investigation. The test results indicate that durability of the copper slag concrete found to be higher resistant to HCl as compared H2SO4 and also normal concrete has better resistance to acid and sulphate attack compared to copper slag concrete.

Separation using self-assembled materials

Abstract

Justification of unconventional protein-containing raw materials for the construction of milk chocolate formulas with increased biological value

Milk chocolate is particularly popular with different age groups. It is characterized by low protein content with a large amount of fats and carbohydrates determining the food imbalance of the product. In conditions of high-grade animal proteins deficiency the selection of high-quality protein-containing ingredients for food production is very relevant. The aim of this work is to study the protein adequacy of various components of milk chocolate to enhance its biological value. The amino acid scale method has been used to assess the biological value of proteins; it is based on the determination of amino acid (chemical) score. It has been found that the limiting biological value amino acid for classical white raw ingredients of milk chocolate (cocoa products and milk powder) is methionine + cysteine. For constructing chocolate formulas with increased biological value it is advisable to use protein-containing raw materials (whey protein concentrate, oat flour, etc.) to compensate for the limiting amino acids. The indicator of amino acids utilitarianity of proteins of raw milk chocolate components has been calculated. On the basis of the utilitarian index we have established the coefficient of utilitarian of the amino acid composition of the raw materials characterizing essential amino acids' balance. We have determined the biological value of protein and the amino acid composition imbalance coefficient. It has been found that the amino acid composition of milk and whey protein concentrates is most balanced compared to the amino acid composition of traditional protein-containing raw components of milk chocolate. The limiting acid of whey protein concentrate is valine, which makes its use in the manufacture of chocolate products more attractive compared to milk protein concentrate (the limiting amino acid is methionine + cysteine). In the group of vegetable non-conventional raw materials oat and buckwheat flour are characterized by the best indicators of biological value. The amino acid adequacy of oat flour is comparable to the qualitative protein indicators of cocoa products, the limiting amino acid is lysine. Buckwheat flour is characterized by the smallest imbalance in amino acid composition, which distinguishes the proteins of this raw material with the highest degree of digestibility compared with the proteins of all the studied protein-containing components of milk chocolate.

A Laboratory Assessment of the Influence of Crumb Rubber in Hot Mix Asphalt with Recycled Steel Slag

To reduce thermal susceptibility and improve rutting and fatigue cracking resistance, increasingly more non-conventional additives and materials have been used in road pavement asphalt mixes in recent years. Non-conventional materials mainly include recycled materials, which reduce production costs and lead to environmental benefits related to their reuse. The aim of this research was to evaluate the influence of recycled tyre rubber in the production of asphalt concrete for road pavements built with recycled aggregates consisting of steel slag in relation to possible improvements in structural performance during operation (i.e., fatigue and rutting). Steel slag has a higher bulk specific gravity than natural aggregates, and it has a very porous surface that allows for a different interaction with the bitumen and the crumb rubber compared to traditional aggregates. To this end, two mixtures of asphalt concrete are compared. One was mixed with a modest percentage by weight of crumb rubber using the “dry” technique, and the other mixture did not contain crumb rubber. Indirect tensile and compression tests with cyclic loads were performed to determine the mechanical behaviour of the two mixtures at different temperatures and under different load frequencies. The results of this research indicate the better performance of the modified mixture with crumb rubber, which agrees with other experiments in the literature that have been made using natural aggregates. Furthermore, a significant increase in stiffness was found at high temperatures (up to 30%), a slight reduction (up to 8%) was found at low temperatures, and a reduction in permanent deformation was found under cyclic loads.

Recent Developments in Plasmonic Nanostructures for Metal Enhanced Fluorescence-Based Biosensing.

Metal-enhanced fluorescence (MEF) is a unique phenomenon of surface plasmons, where light interacts with the metallic nanostructures and produces electromagnetic fields to enhance the sensitivity of fluorescence-based detection. In particular, this enhancement in sensing capacity is of importance to many research areas, including medical diagnostics, forensic science, and biotechnology. The article covers the basic mechanism of MEF and recent developments in plasmonic nanostructures fabrication for efficient fluorescence signal enhancement that are critically reviewed. The implications of current fluorescence-based technologies for biosensors are summarized, which are in practice to detect different analytes relevant to food control, medical diagnostics, and forensic science. Furthermore, characteristics of existing fabrication methods have been compared on the basis of their resolution, design flexibility, and throughput. The future projections emphasize exploring the potential of non-conventional materials and hybrid fabrication techniques to further enhance the sensitivity of MEF-based biosensors.

Evaluation of Physicochemical Properties and Sensory Qualities of Pasta Enriched with Freeze-Dried Sweet Whey

Abstract For food industry, the production of functional pasta from non-conventional raw materials represents a challenge. This study aims to evaluate the potential of animal proteins of freeze-dried whey as a component for pasta production and its effect on the pasta qualities and consumer acceptance. Sweet whey was freeze-dried, then directly incorporated to pasta at a 20% level. Two pasta types (pasta non-enriched vs. enriched with whey powder) were manufactured following a small-scale pilot procedure, and then evaluated for their physicochemical and sensory qualities. Results of all analyses (whey, semolina and pasta) met the standards according to international legislation; however, the characteristics of enriched pasta differed. Whey addition significantly increased ash, proteins content, optimal cooking time and water uptake (P < 0.05); it significantly decreased moisture levels, colour parameters (CIE system: a* redness, b* yellowness) and the swelling index (P < 0.05). Sensory analysis revealed that overall sensory and product quality of enriched pasta was not affected by whey fortification and it was found acceptable by panelists. This study points out that whey powder could be used for the functional pasta production to increase proteins levels.

Recent Developments and State of the Art in Flexible and Conformal Reconfigurable Antennas

Reconfigurable antennas have gained tremendous interest owing to their multifunctional capabilities while adhering to minimalistic space requirements in ever-shrinking electronics platforms and devices. A stark increase in demand for flexible and conformal antennas in modern and emerging unobtrusive and space-limited electronic systems has led to the development of the flexible and conformal reconfigurable antennas era. Flexible and conformal antennas rely on non-conventional materials and realization approaches, and thus, despite the mature knowledge available for rigid reconfigurable antennas, conventional reconfigurable techniques are not translated to a flexible domain in a straight forward manner. There are notable challenges associated with integration of reconfiguration elements such as switches, mechanical stability of the overall reconfigurable antenna, and the electronic robustness of the resulting devices when exposed to folding of sustained bending operations. This paper reviews various approaches demonstrated thus far, to realize flexible reconfigurable antennas, categorizing them on the basis of reconfiguration attributes, i.e., frequency, pattern, polarization, or a combination of these characteristics. The challenges associated with development and characterization of flexible and conformal reconfigurable antennas, the strengths and limitations of available methods are reviewed considering the progress in recent years, and open challenges for the future research are identified.

Adobe como saber ancestral usado en construcciones autóctonas de Pore y Nunchía Casanare Colombia

El adobe es un material de construcción fundamentado en el saber ancestral del acervo popular, principalmente usado en los sectores rurales colombianos y latinoamericanos. Su utilización, en la mayoría de los casos, está ligada a la dificultad de acceso a materiales convencionales de construcción, generado por la desconexión y distanciamiento con las zonas urbanas, y a las dificultades económicas de dichos sectores de la población. Sin embargo, algunas poblaciones han optado por mantener la tradición del uso de este tipo de materiales no convencionales, salvaguardando las tradiciones que esto implica. Dada su relevancia popular e implicaciones arquitectónicas, se presenta un estudio sobre el uso del adobe en los municipios de Nunchía y Pore del departamento de Casanare. La metodología aplicada abarca etapas como la observación directa a construcciones en adobe, fichas técnicas especializadas a muestras a partir de ensayos de laboratorio para el estudio de sus propiedades mecánicas, encuestas semi estructuradas y entrevistas a persona con experticia en su elaboración. Se busca con este trabajo valorar y salvaguardar el conocimiento ancestral de las técnicas de procesamiento y las propiedades del adobe, como una manifestación patrimonial bajo amenaza de disipación debido al uso de materiales convencionales.

Processing of platinum group metal ores in Russia and South Africa: current state and prospects

The presented study is devoted to a comparative review of the mineral raw material base of platinum group metals (PGMs) and technologies of their processing in South Africa and Russia, the largest PGM producers. Mineralogical and geochemical classification and industrial value of iron-platinum and platinum-bearing deposits are presented in this work. The paper also reviews types of PGM ore body occurrences, ore processing methods (with a special focus on flotation processes), as well as difficulties encountered by enterprises at the processing stage, as they increase recovery of the valuable components. Data on mineralogical features of PGM deposits, including the distribution of elements in the ores, are provided. The main lines of research on mineralogical features and processing of raw materials of various genesis are identified and validated. 
 Sulfide deposits are found to be of the highest industrial value in both countries. Such unconventional PGM sources, as black shale, dunites, chromite, low-sulfide, chromium and titanomagnetite ores, anthropogenic raw materials, etc. are considered. The main lines of research that would bring into processing non-conventional metal sources are substantiated.
 Analysis of new processing and metallurgical methods of PGM recovery from non-conventional and industrial raw materials is conducted; the review of existing processing technologies for platinum-bearing raw materials is carried out. Technologies that utilize modern equipment for ultrafine grinding are considered, as well as existing reagents for flotation recovery; evaluation of their selectivity in relation to platinum minerals is presented.
 Basing on the analysis of main technological processes of PGM ore treatment, the most efficient schemes are identified, i.e.,gravity and flotation treatment with subsequent metallurgical processing.

Construction of a large oedometer for MSW and non-conventional materials testing

The design, construction and evaluation of a large consolidometer for testing municipal solid waste (MSW) and other non-conventional materials is proposed. The apparatus features leachate recirculation and biogas production monitoring. Furthermore, it is equipped with moisture content sensors, suction and at-rest lateral earth pressure measuring capabilities. Fresh MSW samples were collected from a metropolitan centre landfill and were used to test performance and conduct MSW mechanical behaviour analyses. Values of vertical stress (σz) ranging from 10 to 1000 kPa were employed in the test, which lasted for approximately 1 year. The results show that the secondary compression index was affected by sample saturation and that biogas composition acted as an indicator of the MSW phase of decomposition. Lateral earth pressure at rest values increased with σz, although they decreased over time for the same loading stage. Values of primary compression and swelling indexes (cc and ce, respectively) are close to those reported in the literature for similar material.

A review of Solid Oxide Fuel Cell cathode materials with respect to their resistance to the effects of chromium poisoning

Solid Oxide Fuel Cell (SOFC) cathode materials have been shown to be susceptible to a ‘chromium poisoning’ phenomenon that can significantly deteriorate cell output during operation. Chromium-containing species, released from stack and system materials, migrate to the SOFC cathode where they are able to form new phases through reaction with the cathode material. Such phases have been shown to diminish the catalytic and conductive performance of the electrodes and even block the pathways through which oxygen must diffuse. To date, there has been a significant body of research afforded to this subject area. Efforts have been made towards understanding the chromium poisoning effect, whilst also considering how it may be mitigated. In this review, we discuss the effects of chromium-containing phases on both conventional and non-conventional cathode materials. This is in order to understand the most successful approaches towards developing chromium-tolerant cathode materials. The influences of environmental parameters such as temperature and humidity are also discussed. This is to explore how degradation rates may be affected by the operating conditions themselves and the extent to which the phenomenon can be mitigated by suitable control of such factors. In the most part, these environmental effects are studied in relation to the most common cathode materials, La1-xSrxCo1-yFeyO3 and La1-xSrxMnO3, where there has been the largest body of work conducted.

Why nonconventional materials are answers for sustainable agriculture - ADDENDUM

The following footnote should be included in this article [1]: This paper was commissioned and accepted for publication by David Cahen, who served as Editor-in-Chief of this journal from 2014-2018.