Canola meal as a by-product from the vegetable oil production provides a protein-rich material which is available This study investigated the potential of Burkina Faso’s local kaolin clay in formulation of geopolymer bricks. The formulation used a mixture of raw clay and activator alkaline solutions with varying concentrations. Prismatic molds were used to shape geopolymerized adobes. The physicochemical characteristics of the samples, including water absorption, linear shrinkage, density, porosity and spray test, were determined after 28 days. According to the standard NF P 15-471 mechanical analyses revealed that the geopolymer, formulated from locally sourced clay and a (NaOH + sand) solution with 10M concentration, exhibited favorable performance characteristics essential for civil engineering construction. These include a maximum linear shrinkage of 5.31%, a density ranging from 1.607 g.cm-3 to 1.900 g.cm-3, porosity of 29.90%, acceptable mass loss following a rain erosion test of 0.56%, and excellent compressive strength of 28 MPa. Mineralogical characterization results demonstrated that all formulated bricks contain quartz, kaolinite, goethite and a novel phase Na2(AlSiO4)6(OH)2.2H2O.
The paper investigates the differences in the chemical composition of the selected Cem 1 cement brands in Kenya and their effect on mechanical properties of concrete. It also investigates if the differentiation in mechanical properties of concrete prepared from different cement brands affects its service life. Currently, there are nine cement manufacturers in Kenya, the majority of whom produce Cem 1 cement along with other grades. To achieve the desired objective, three cement brands; Cem A, Cem B and Cem C of Cem 1 were used in preparation of concrete samples for testing. Other concrete constituent materials; fine and coarse aggregates and steel were obtained from the local Kenyan market suppliers. The physical and chemical properties of the materials were investigated to ensure compliance with relevant applicable standards. Concrete of characteristic strength of 25N/mm2 derived from the DOE method was used. Concrete materials were batched by weight and mixed by a lab electric pan concrete mixer in batches of 0.009 m3 . The concrete batches were tested for consistency by the slump and compaction factor tests. For each brand of cement 9 cubes of 150mmx 150mm x 150mm for compression test, 9 cylinders of 150mm x 300mm for tensile strength were cast. After 24 hours the cast specimens were demolded and immersed in curing tanks for 27 days. Specimens for compression and tensile test were tested at 7,14 and 28 days. From the results in the research, the different Kenyan selected cement brands affect the compressive strength which influences the rate of infiltration of corrosion agents affecting the service life of reinforced concrete. The variation in chemical composition must be taken into account when formulating the concrete mix design for specific structural purposes.
Silicon multilayer thin films consisting of alternating amorphous SiOx (a-SiOx) and nanocrystalline silicon (nc-Si) layers were fabricated on p-type silicon substrates using a sol-gel spin-coating method. Boron-doped silicon powders, prepared through prolonged grinding, were mixed with a TEOS–ethanol sol-gel solution, and two nc-Si layers embedded in a-SiOx were sequentially deposited. The as-grown films were annealed at 100–400 °C and characterized using Raman spectroscopy, GXRD, FTIR, SEM, Resistivity and UV spectroscopy to analyze their structural, chemical, optical, and electronic properties. Annealing progressively enhanced crystallinity and increased the <111> and <110> grain sizes to ~11 nm and ~12 nm, respectively. Films annealed at higher temperatures showed a minimum mobility of ~37.5 cm²/V·s, maximum resistivity of ~7.35 Ω-cm, and a decreasing optical bandgap. Enhanced nanocrystal growth, reduced defects, and improved structural ordering intensified the 520 cm⁻¹ Raman peak. The multilayer architecture further strengthened these effects by offering additional nucleation sites, controlled nanocrystal confinement, defect-relaxing interfaces, improved phonon transport, and enhanced Si diffusion, resulting in superior crystalline quality.
The Larson–Miller constant (C) of martensitic steel, which is used as the Larson–Miller parameter, is considerably larger than the typically used value of 20 for many types of heat-resistant steels. To provide better understanding regarding this fact, an analytical formulation for the Larson–Miller constant is developed using a model based on interactions between moveable dislocations and elastic singularities in a system. To verify the proposed equation, eight types of Grade 91, 92, and 122 steels are used, whose maximum rupture life exceeds 1E5 h. Creep data are classified into 257 groups by temperature, stress, and strain or time. C values are obtained by applying multiple-regression analyses to time parameters that obey the exponential law, assuming a thermally activated process. C and Ccal are calculated for each data group based on an exponential law and a proposed equation, respectively. The statistical values for C and Ccal are as follows: ̄C=32.41, Cmin=7.87, Cmax=64.88, and (Ccal⁄C)=99.3%. Although (∆C)̄=(Ccal-C) ̅=0.02 is extremely low, the standard deviation of ∆C is large, i.e., 1.27. Results confirmed that the proposed equation can estimate wide-ranging C values, although the equation is expected to be improved. A major component of C for C>15 is an increase in the entropy change caused by elastic interactions between moveable dislocations and elastic singularities in a system.
The leading cause of deterioration in reinforced concrete structures is the corrosion of steel bars embedded in concrete in the aggressive environment. This includes carbonation of concrete due to high CO2 concentration, chloride rich regions such as in marine environments from the sea water or airborne chloride and the corrosive industrial zones. In the recent past, nano-materials have risen to lime-light as one of the promising class of materials providing good corrosion protection to reinforced concrete structures. This class of materials include nano-silica, nano-alumina, carbon nano-tubes, nano-clays, graphene oxide, nano-coatings, nano-inhibitors as well as nano-particles of metal oxides. The mechanism of action for these nano-materials depends on the type of material used. For instance, some may refine the pore structure of concrete and reduce the permeability of concrete. Others may enhance the interfacial transition zone between the steel reinforcement bars and concrete. All this helps to limit the ingress of harmful substances including moisture, chloride ions, carbon dioxide and oxygen. Yet some other types of nano-materials may provide a protective layer or barrier through absorption, adsorption or reaction with the steel rebar surface and/or improvement in the passive layer. Nanomaterials have a multi-functional role and may also improve the mechanical properties along with the improvement in corrosion related durability. They may also influence the electrical resistance and may provide a self-healing behavior as well. Despite all the advantages, some challenges remain to be overcome such as dispersion, long term effect, impact on environment, scale and cost-benefit ratio.
This report presents a comprehensive review of North American research in Materials for Sustainability, with a focus on Canadian contributions and their potential applications in defence. A combined literature review and scientometric analysis of over 10,000 publications from 2014 to 2024 identified six major research domains: recycling, advanced materials, advanced manufacturing, low-carbon raw material production, alternative fuels, and energy storage technologies. Canadian research shows particular strength in biocomposites, green concrete, and hydrogen-related materials. The study highlights emerging trends, research momentum, and topic interconnectivity, offering insights into how materials science can support climate mitigation and adaptation. Defence applications include lightweighting, infrastructure resilience, and low-emission energy systems, especially for Arctic environments. The report concludes with recommendations for targeted R&D to advance sustainable materials in dual-use and defence applications.
Activation volume is an essential factor to determine the strain rate of martensitic steel, however it has not been discussed extensively. The activation volume during creep is analytically formulated as a function of average activated moving dislocation density (ΚρaX) inside a small region, e.g., a sub-grain, assuming the slip motion of dislocations. For Grade T91 steel, the activation volumes (V’s) for time to a specific creep strain and time to rupture are calculated by applying an exponential law to the temperature, stress, and time parameters during creep. The ΚρaX’s obtained using the calculated activation volumes are compared with the observed dislocation densities (Ρob’s). ΚΡaX at a strain of 0.2% is roughly 10% of the initial ρob, and the ratio of ΚρaX / ρob increases toward a value smaller than 1 at rupture because of recovery. These results and the strain energy consideration indicate that all dislocations inside a limited number of lath martensite begin to slip or a considerable number of packets remain undeformed immediately after loading. Subsequently, a large number of dislocations are accumulated on the boundaries of the concerned lath martensite, block, and packet, promoting the recovery and precipitation reactions around the crept area. Consequently, heterogeneity of deformation at the beginning of creep is mitigated gradually with progressing creep. The above documents coincide with a proposed model of the activation process for creep.
In this paper we obtained exact analytical solutions for the bound states of a Dirac electron in graphene with a magnetic field proportional to the Eckart plus Hulthen potential, and Rosen-Morse potential II plus Woods-Saxon. We used the parametric Nikiforov-Uvarov method to solve the time independent Dirac-Weyl equation. We also presented the energy spectra of HCl, ScH, ScN, and ScF molecules, and showed that some molecules can have energy and others not, or all can have energy or not, for the same given quantum number n.
The present study concerns the improvement of the bearing capacity of a reddish clay lateritic gravel (GLAR) by adding a quantity of crushed granite 0/31.5 in order to use the mixture as a road base course. Geotechnical tests were carried out on natural GLAR, and Geo-concrete composite based on GLAR improved with 0/31.5 mm crushed granite stone at three mass ratios (20wt%, 30wt% and 40wt%). The results show a reduction in the Plasticity Index from 18.7% for the natural lateritic material, to 12.2%, 11.0% and 7.3% respectively at the 20wt%, 30wt% and 40wt% crushed granite amendment mass rates, representing a reduction from 34.76% to 60.96%. Analysis of the geo-concrete composite’s compactness showed that the dry density of the new composite increased by 2.81%, 4.75% and 17.36% with the introduction of Crushed granite 0/31.5 in the GLAR. Moreover, the 95% CBR bearing capacity of OPM has been improved by 2.94%, 5.88% and 27.94% respectively at 20wt%, 30wt% and 40wt% addition of crushed granite material. These results are in line with CEBTP 2014 specifications and indicate that these lateritic gravels reinforced with 0/31.5 mm crushed granite at rates of at least 20% can be used in road construction for the base course. Optimum mechanical stabilization or litho- stabilization is achieved with a 30% incorporation of crushed granite material in GLAR.
The microstructural length scale of metals changes by orders of magnitude under extreme processing conditions producing a concurrent wide range of mechanical strength and plasticity behaviors. A unified stress-strain σε model is formulated that’s based on superposing the components of asymptotic-curvilinear work hardening Θσ to qualify and quantify these mechanical behaviors. This approach accounts for the rapid strengthening of metals beyond the initial yield point, through extended steady-state deformation, to the structural instability. The relationship between the softening coefficients cbi of the work hardening formulation Θσ and strength are found to reveal the microstructural scale in the material. Specifically, the rapid decrease in the slope of the Θσ curve provides a measure for microstructural size consistent with a functional Hall-Petch relationship of strength. A successful application is shown for the tensile behavior of pure aluminum microstructures that result from extreme plastic deformation by equal-channel angle pressing.
WO3-based photochromic composite films were fabricated using transparent urethane resin and iso-polytungstic acid peroxide (W-IPA). We attempted to improve its photochromic properties by adding elements on the 5th period: Y(+3), Zr(+4), Nb(+5), and Mo(+6). When yttrium chloride was added to the raw material, W-IPA, yttrium could not be added to WO3 because it reacted with W-IPA. The coloration rate of WO3 photochromic composites increased with the addition of Zr, Nb, and Mo. The bleaching rate of the WO3-based composite films increased significantly with Zr addition, approximately 2.3 times faster than that of the non-doped film. The photochromic properties of the Zr/WO3 composite films were also evaluated under sun light irradiation. All the films exhibited reversible photochromic properties in a one-day cycle. The degree of coloration significantly changed with sun light irradiation in summer (during the summer solstice) and winter (during the winter solstice). In summer, the coloration properties were adequate after 25 min of sunlight irradiation, and the bleaching properties returned to near the initial transmittance after 6 h of storage in the dark. These results indicate that the Zr/WO3 composite films could be effectively controlled under sunlight in both winter and summer. Therefore, these films can be applied as smart windows.
A unified model for the work hardening Θσ and stress-strain σε behavior is presented that accounts for deformation under tensile loading, from the onset of yielding at the proportional limit up to the ultimate strength as defined at the structural instability. The origin of this approach is based on a negative exponential formulation for an asymptotic-curvilinear work-hardening model that accounts for the rapid strengthening of metals as well as the continuation of steady-state deformation to the instability.
Aluminum-doped cadmium oxide (CdO:Al) thin films were deposited onto glass and silicon substrates using the sol–gel spin-coating method, with deposition time varied as a key parameter. Cadmium acetate dihydrate served as the precursor material, while aluminum nitrate was used as the aluminum dopant source. The structural, optical, and electrical properties of the CdO:Al films were characterized using X-ray diffraction (XRD), Raman spectroscopy, Ellipsometry, Surface roughness analysis, Fourier-transform infrared spectroscopy (FTIR), Electrical resistivity, and UV-Vis spectroscopy. XRD analysis revealed characteristic peaks at 2θ values of 25.89°, 38.36°, 38.9°, and 44.49° on both substrates for deposition times of 5 and 30 seconds. An additional peak at 2θ = 33° was observed only on the silicon substrate. XRD peak intensity increased with longer deposition times on both substrates. Crystallite sizes at 30 seconds were determined to be 32.08 nm on glass and 38.29 nm on silicon. The lowest deposition rates were 273.25 nm/sec for glass and 210.11 nm/sec for silicon at 30 sec. Roughness measurements indicated that silicon substrates exhibited lower RMS roughness values compared to glass. Raman spectra confirmed the presence of the crystalline CdO:Al phase with a peak at 808 nm for both substrates, and Raman intensity increased with deposition time. At 30 seconds, the refractive index and dielectric constant were found to be 3.52 and 0.15 on silicon, and 1.52 and 0.08 on glass, respectively. FTIR analysis confirmed CdO:Al presence with absorption bands at 610.91 cm⁻¹ (silicon) and 615.71 cm⁻¹ (glass). The lowest resistivity values recorded were 1.2 X10-5 Ω·cm on silicon and 3.6 X 10-4 Ω·cm on glass. UV-Vis spectroscopy estimated the optical band gap energies to be 2.8 eV for silicon and 3.1 eV for glass. The results showed that the Al-doped CdO films made by the sol-gel method on silicon acted like highly conductive semiconductors.
Titanium dioxide (TiO2) thin films have been deposited on Corning 7059 glass and Fused quartz silicate substrates using Sol-Gel spinning coating technique. The effect of annealing temperature on the structure, surface morphology, optical and electrical properties of these films are characterized by Raman, XRD, FT/IR, UVvis and four-point-probes measurements. On glass substrates, there are four Raman active bands are observed: 3Anatase [A<149 cm-1>, A<523 cm-1> and A<646 cm-1>] and 1 Rutile B<401 cm-1>. On silica substrates, additional two more bands which are R<859 cm-1> and B<1068 cm-1> detected. The deposited films show polycrystalline nature with high XRD intensity peaks in (110), (200) and (211) orientation corresponding to anatase and rutile phases respectively with tetragonal BCC structure. The other orientations (101), (111), (210), (211), (220), (201), (002), (204) and (116) are also observed for all films with low intensities. XRD crystal sizes are found to increase with increasing annealing temperature on both substrates. Maximum crystal sizes are found to be ~31 nm on silica substrates and ~23 nm on glass substrates at 500 oC. On glass substrate, TiO2 thin film shows the agglomeration of various non- uniform flaky-type of structures. On silica substrate, the FESEM micrographs shows the following observations: (i) particles are spherical in shape with forming different islands (ii) particles are soft agglomerates/spongy in nature with uniform surface, (iii) each spherical agglomerate contains many particles in the nanometric range and (iv) the agglomerate size is in between 40 and 110 nm. FE-SEM TiO2 particles size distribution at 500 oC showed that the average particle size is 89.55 and 110.35 nm on glass and silica substrates respectively.
Reviewer acknowledgements for Journal of Materials Science Research, Vol. 12, No. 2, 2023.
This paper studies, by means of Monte Carlo simulations, an open ferromagnetic spin-3/2 Ashkin-Teller model defined on a square lattice. This model can be viewed as the superposition of two Ising models which are coupled by a four-spin interaction strength K4while in each Ising model, the nearest-neighbor interaction constant is K2. The model is here submitted to two stochastic dynamics that consist of two processes; the first one is the Glauber dynamics which simulates the contact of the system with a heat bath at temperature T and the second one is the Kawasaki dynamics which simulates the continuous energy flux into the system from an external source. The Glauber single-spin flip process happens with the probability p while the Kawasaki spin-exchange process between neighboring sites occurs with the probability q = 1− p. The temperature-dependence of the system magnetizations for fixed coupling constants and lattice anisotropy has been thoroughly investigated. Several thermodynamic phases and phase transitions have been obtained as well as multicritical points. When the Kawasaki dynamics becomes dominant, self-organized antiferromagnetic phases are generated. Several phase diagrams have been devised to illustrate model thermodynamic properties.
Canola meal as a by-product from the vegetable oil production provides a protein-rich material which is available in large quantities but with limited areas for application. The objective of this study was to investigate the possibility of utilizing canola meal adhesive for the production of wood fiber insulation boards (WFI) using the hot-air/hot-steam-process. WFI with two different thicknesses (40/60 mm) and different densities (110/140/160/180 kg/m³) were manufactured. The testing focused on their physical-mechanical properties such as internal bond strength (IB), compressive strength (CS) and short-term water absorption (ST-WA) measured according to European standards. For a better understanding of the material and curing dynamics, the canola meal was analyzed on its protein content, lignin and pentosane content as well as its extractives content using hot water, cold water and successive extraction. Using a canola meal based adhesive resulted in promising results for IB and CS up to density of 140 kg/m³. Nonetheless, there is place for improvement for the ST-WA.
Natural dyes are very useful for dyeing textile fibre. Natural dyes have been used for long back. In the Mughal regime, it was found that natural dyes were used to dye textile materials. Starting from the Muslin to the household textiles the use of natural dyes was significant. For more than a hundred years, it was evident that synthetic dyes become popular for dyeing textile material. Natural dyes for jamdani sarees are not easily available in Bangladesh. These dyes are imported from outside of Bangladesh and for this reason, this type of dyes is not available in the local market. But at the same time, the risk of using synthetic dyes is high for human health because of cause different health hazards like breathing problems, skin diseases and skin cancer. Compared to synthetic dyes natural dyes are not easily available and they are costly at the same time. The unavailability of natural dyes made the use of synthetic dyes more popular among the manufacturers of textile products. Though natural dyes are sustainable, due to unavailability and high cost it is hindering the acceptance to use natural dyes. In this study, it was evident that natural dyes normally have significant eco-friendly properties especially the absence of banned amines compared to synthetic dyes. It was found that synthetic dyes have banned amines.
The analysis of the work hardening variation with stress reveals insight to operative stress-strain mechanisms in material systems. The onset of plasticity can be assessed and related to ensuing plastic deformation up to the structural instability using one constitutive relationship that incorporates both behaviors of rapid work hardening (Stage 3) and the asymptotic leveling of stress (Stage 4). Results are presented for the mechanical behavior analysis of Ti-6Al-4V wherein the work hardening variation of Stages 3 and 4 are found to: be dependent through a constitutive relationship; be useful in a Hall-Petch formulation of yield strength; and provide the basis for a two point-slope fit method to model the experimental work hardening and stress-strain behavior.
The aim of the study is to formulate a new composite material for road pavement by combining asphalt concrete with waste plastic bags (WPB). The study focused on enhancing the physical and mechanical properties of the composite materials by adding varying proportion of WPB. WPB is prepared simply by cleaning and melting them at 300 °C. Then, the melted WPB is mixed with asphalt at 170 °C for 2 to 3 minutes. The resulting mixtures contained different content of WPB by weight such as 0wt%, 5wt%, 10wt%,15wt% and 20wt%. The homogenized mixtures underwent penetration and softening point tests. Additionally, Marshall stability tests were conducted with 0/14 aggregates, along with asphalt concrete (AC) flow tests, Duriez stability reports, and AC compacity tests. The water content of AC was also examined. The results show that as the content of WPB increased, penetration values exhibited a consistent linear decrease. The incorporation of WPB resulted in an average increase of 22.64% in the softening point of asphalt. Increasing the content of WPB led to an average 72.07% rise in Marshall stability, accompanied by a concurrent 29.47% decrease in AC flow. In addition, at 10wt% WPB incorporation, there was an optimal Voids in Mineral Aggregates (VIM) value of 2.07%. The Duriez test revealed an average increase of 15.18% in the stability of asphalt concrete. The compacity of asphalt concrete (AC) experienced an increase, and concurrently, the AC water content also increased. Conclusively, the incorporation of melted WPB effectively improved the physical and mechanical properties of asphalt, showcasing promising prospects for road pavement applications. The study suggests that the polymer-modified asphalt is achieved with WPB loading optimal ranging from 5wt% to 10wt%. This innovative approach holds potential significance, especially in underdeveloped countries where there is an abundant supply of waste plastic bags.
