Mechanical Strength Values Research Articles

Influence of PMMA on properties of polymer electrolyte based on epoxidized deprotenized natural rubber

The effect of co-polymer, i.e. poly(methyl methacrylate) (PMMA), and doping salt, i.e. lithium trifluoromethanesulfonate (LiCF3SO3) inthe epoxidized rubber-polymer blends preparation was evaluated. The electrolyte membrane was developed through solution castingmethod in the presence of 0-50wt.% of LiCF3SO3. The influence of LiCF3SO3 on chemical interaction and structure, ionic conductivity,mechanical properties, and glass transition temperature (Tg) of 45%-epoxidized deproteinized natural rubber (EDPNR45)-PMMA (80/20) membrane was determined using several techniques, i.e. F-IR, universal testing machine, multipotentiostat, and DSC. Infrared analysis showed that lithium salts might formed coordination bonds with the oxygen atoms of PMMA and EDPNR45. Ionic conductivity of EDPNR45/LiCF3SO3 blends have been evaluated and the highest conductivity (σ) was obtained in the presence of 35 wt.% of lithiumtrifluoromethanesulfonate (1.71 x 10-5S.cm-1). The PMMA content’s effect was also evaluated on the properties of EDPNR45/LiCF3SO3.The highest conductivity and mechanical strength values at EDPNR45/PMMA ratio of 80/20. Enhancing trend of Tg was obtained withthe increase of PMMA and salt concentration. FTIR characterization also confirms the interaction of salt with EDPNR45 and PMMA.

Technological and Quality Aspects of the Use of Innovative Inorganic Binders in the Production of Castings

The production of cores for the pre-casting of holes in castings places high demands on the quality of the molding mixtures used. For this reason, organic binders are still used to a large extent, which, although they meet the technological requirements, are a source of pollutant emissions during the production of castings. The current trend towards greening production is therefore looking for a suitable alternative in ‘green’ inorganic binders. Although for many decades standard inorganic binders could not be compared with organic resins in terms of technological properties, new inorganic binder systems are currently being developed that can largely eliminate these disadvantages, which include, in particular, significantly lower collapsibility and reclaimability, and lower mechanical strength values. Last but not least, the use of these binder systems may be limited by the technological parameter of shelf-life, which is the main focus of this study. The aim of this paper is to evaluate the influence of technological parameters of core production using a new generation of inorganic binder systems on their shelf-life. Shelf-life, defined as the change in mechanical strength and wear resistance as a function of exposure time in a given environment, is evaluated under different climatic conditions.

Preparation of 3‐pentadecylphenol‐modified cellulose nanocrystal and its application as a filler to polypropylene nanocomposites having improved antibacterial and mechanical properties

AbstractPolypropylene (PP) nanocomposites were prepared using cellulose nanocrystal (CNC) grafted with 3‐pentadecylphenol (PDP) as a filler. Functionalized CNC (f‐CNC) was prepared by the reaction of CNC with 4‐oxo‐4‐(3‐pentadecylphenoxy)butanoic acid (PDPBA), where PDPBA was synthesized by reacting succinic anhydride (SA) with PDP. PP nanocomposites containing CNC (PP/CNC) and f‐CNC (PP/f‐CNC), respectively, were prepared to study the effect of fillers on PP. PP/CNC and PP/f‐CNC showed improved mechanical stiffness, and especially, PP/f‐CNC was found to have larger mechanical strength value than neat PP and PP/CNC due to the PDP moiety having a long alkyl group in f‐CNC. Antibacterial property was observed both from PP/CNC and from PP/f‐CNC while that of PP/f‐CNC was better than that of CNC because PDP could impart the additional antibacterial activity. The improved mechanical properties and antibacterial property of PP/f‐CNC could be ascribed to the respective effect of PDP and CNC.

Research on desktop 3D Printing Multi-Material New Concepts

3D printing or Additive Manufacturing (AM) was originally born as a mono-material technology. And, nowadays, most of the applications are still using only one material. AM has a lot of potential but has not yet been fully explored, and access to the creation of multi-material products is an example of it. One of the most interesting areas is the introduction in the same part of materials with different rigidities, stiffer and softer areas, with differentiated values of mechanical strength and viscoelasticity. In the present work, a general vision of Additive Manufacturing under the vision of mono- and multi-material processes is given, and some existing 3D printing multi-material experiences related to Material Jetting (MJ) and Material Extrusion (ME) are briefly described. But it is in this latter field, linked to Desktop 3D printing (more accessible than typical proprietary industrial equipment), where on-going research could easily be spread: five research ME concepts are then presented, from a revolver print-head to silicone UV 3D printing, with their initial embodiment in the form of prototypes or/and testing, as a way to verify the difficulties that would be encountered in the transition from research to reality.

Incorporation of 45S5 bioglass via sol-gel in β-TCP scaffolds: Bioactivity and antimicrobial activity evaluation

In this work, β-TCP (β-tricalcium phosphate) bioresorbable scaffolds were prepared by the gel casting method. Then, they were impregnated with a 45S5 bioglass sol gel solution to improve biocompatibility and promote bioactivity and antimicrobial activity. The β-TCP scaffolds had an apparent porosity of 72%, and after the incorporation of the bioglass, this porosity was maintained. The elements of the bioglass were incorporated into β-TCP matrix and there was a partial transformation from the β-TCP phase to the α-TCP (α-tricalcium phosphate) phase, besides the formation of bioactive calcium and sodium‑calcium silicates. The scaffolds β-TCP with 45S5 bioglass incorporated (β-TCP/45S5) did not show a reduction in their values of mechanical strength and Weibull modulus, despite the partial transformation to the α-TCP phase. Bioactivity, cell viability, and antimicrobial activity improved significantly for the β-TCP/45S5 scaffold comparing to the scaffold without the bioglass. The mineralization of carbonated hydroxyapatite was verified in Simulated Body Fluid (SBF). The cell viability, evaluated by the reduction of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide – MTT in MG63 cells, increased by 178%, and β-TCP/45S5 scaffold also enhanced cell activity and osteoblast differentiation observed by means of total protein contend and alkaline phosphatase activity, respectively. The formation of growth inhibition zones was also observed in the disk diffusion assay for three tested microorganisms: Staphylococcus aureus, Escherichia coli and Candida albicans. To conclude, the vacuum impregnation method in 45S5 bioglass sol gel solution was effective in penetrating all the interconnected macroporosity of the scaffolds and covering the surface of the struts, which improved their biological properties in vitro, bioactivity and antibacterial activity, without reducing mechanical strength and porosity values. Thus, the β-TCP/45S5 scaffolds are shown as potential candidates for use in tissue engineering, mainly in bone tissue regeneration and recovery.

Characterization and chromatic evaluation of gypsum-based pastes for construction and heritage restoration

This research evaluates the chromatic behavior of gypsum-based pastes containing added pigments which enable their use in both new construction projects as well as in restoration interventions for built heritage. Furthermore, the impact of adding pigments to the aforementioned material after twenty-eight and ninety days has also been studied. This was confirmed by carrying out compositional, mineralogical and physical studies of the raw materials and the pastes. The results indicate that all of the pastes studied have suitable mechanical strength values for the type of pastes studied, thereby confirming their suitability for on-site use based on their characteristics and behavior. Colorimetric analysis showed color variations that were clearly perceptible to the human eye, related to increases in luminosity which significantly exceeded 100%, and also to saturation losses featuring percentage variations of more than 100% on assessment after ninety days. This colorimetric analysis by means of quantitative spectrophotometry is of vital importance when determining the loss of color intensity of the pastes used, since subjective observation results in serious errors of interpretation. This type of study reflects the use of instrumental color measurements for this type of materials and mixtures.

Process Parameter Optimization and Characterization for an Edible Film: Flaxseed Concern

Consumer demands for biocompatible, minimally processed and eco-friendly foods have increased drastically and are currently trending. Polysaccharides derived from various plant seeds exhibiting structure conformational diversity are among such foods and used for the development of edible films. In this study, the physical properties of flaxseed, proximate characterization and rheological, mechanical and thermal features of flaxseed meal-based edible films were investigated. A development strategy worked through adding pectin + flaxseed meal to a plasticizer (glycerol) with a ratio of 7:3 w/v, whereas, in the control group, the flaxseed meal remained unaltered. The rheological results showed the non-Newtonian behavior of film-forming solutions and data were well fitted into the power law model. The developed film (flaxseed + pectin) was slightly brownish and exhibited a transparency of 17.78, which is clear enough to be used as see-through packaging material, whereas the control sample had a transparency of 38.25, indicating its fair transparency. The water vapor permeability of the test sample was also beneficial (0.992 g/cm2/24 h) and was competitively close to the control (0.981 g/cm2/24 h). The developed blended films were 98–99% soluble in water and acid, indicating their usefulness when applied as a coating. The mechanical properties, tensile strength and elongation value of the test sample were less than the control. This study will be helpful in the development of a novel biodegradable film for extending the life of different foods.

Effects of the addition of graphene on the compressive strength of geopolymeric mortar developed from k-feldspar mining waste

Contemporary organizations are showing a growing interest in the reuse of solid waste from industrial processes with the intention of reducing environmental impacts and reducing costs. The mining activity is one of the main waste generators in Brazil. In parallel, geopolymeric materials have been gaining prominence in studies that make it a possible substitute for ordinary Portland cement, due to its environmental advantages. Therefore, the present research proposes to study the feasibility of using K-feldspar mining waste as a possible raw material for the manufacture of geopolymer cements. In addition, in line with the latest technological trends, the addition of multi-layered graphene was evaluated as a structural reinforcement for geopolymeric mortar. Graphene was added in three percentages: 0.1 wt.%, 0.3 wt.% and 0.5 wt.%. Specimens were produced in order to evaluate the compressive strength of these materials. As a complementary characterization, the analysis of EDX, laser diffraction particle size and XRD of the waste were performed, as well as SEM and TEM analysis of the graphene used. The results showed that the geopolimerization was effective and that the 0.5% graphene content promoted a significant increase of 65% in the compressive strength. It is concluded, therefore, that with the achieved mechanical strength values, the studied waste can be applied as mortar in auxiliary structures using the geopolymerization technique and that graphene can be used to promote increases in the mechanical strength of the material produced.

Long‐term stability of sensible thermal energy storage materials developed from demolition wastes interacting with hot heat transfer fluid

Packed-bed thermal energy storage (TES) system filled with low cost and sustainable sensible thermal energy storage material (STESM) is a promising option for medium–high temperature applications. STESM developed from demolition wastes are eco-innovative and compatible with circular economy. They can be used in solar heat industrial applications up to 750°C. One of the main concerns that should be taken into consideration is the stability of STESM developed from demolition wastes in direct contact with hot heat transfer fluids (HTFs). In this study, thermal and mechanical stability of STESM developed from demolition waste were investigated using repeated heating and cooling cycles in Therminol 66 synthetic oil as HTF at 150°C for up to 500 hours. The characterization results before and after thermal cycling showed that new STESM developed from demolition wastes is thermally and mechanically stable. Also, strong oil penetration into the STESM samples improved the porosity, strength, and specific heat capacity. The specific heat capacity and mechanical strength values increased from 1330 to 1490 J/kgC and from 4 to 6 MPa, respectively. These results suggest that STESM samples developed from demolition waste can be used reliably in solar heat industrial applications for long term.

Comparison between growth performance in two silvopastoral systems comprising trees, short-lived perennial shrub, a forage, and livestock)

We aim to determine the growth performance of two 20-year-old silvopastoral systems comprising two timber trees, a palm tree), a short-lived perennial shrub, a forage and livestock; and to investigate fibre features and certain physical and mechanical properties of two timber trees (Myracrodruon urundeuva and Peltophorum dubium) in two plantation systems. The first system is called MP with two timber trees and the second one is called MPS with two timbers and a palm tree. The studied systems showed that it was possible to successfully combine fast-growing species, animals, forage and woody tree species, with a production cycle of more than 50 years of different goods and services (e.g., ornamentals, palm hearts, landscaping, fruits, seeds, bee pasture, meat, and wood). The height, diameter and volume for M. urundeuva trees in the MP system were greater than in the MPS system, whereas no difference between the systems was observed for P. dubium. By comparison, the growth and volume in P. dubium were greater than in M. urundeuva. For wood properties, it was shown that both systems can be used successfully, but the MPS system performed better than the MP system, in the aim of wood production of high mechanical strength and calorific value. In addition, the MPS intercropping system can yield more goods and services than the MP system, both systems bring returns with short-term (bean seed, forage, pasture), medium-term (forage, palm products, pasture, wood), and long-term (wood) financial returns.

Crushed Bricks: Demolition Waste as a Sustainable Raw Material for Geopolymers

Demolition activity plays an important role in the total energy consumption of the construction industry in the European Union. The indiscriminate use of non-renewable raw materials, energy consumption, and unsustainable design has led to a redefinition of the criteria to ensure environmental protection. This article introduces an experimental plan that determines the viability of a new type of construction material, obtained from crushed brick waste, to be introduced into the construction market. The potential of crushed brick waste as a raw material in the production of building precast products, obtained by curing a geopolymeric blend at 60 °C for 3 days, has been exploited. Geopolymers represent an important alternative in reducing emissions and energy consumption, whilst, at the same time, achieving a considerable mechanical performance. The results obtained from this study show that the geopolymers produced from crushed brick were characterized by good properties in terms of open porosity, water absorption, mechanical strength, and surface resistance values when compared to building materials produced using traditional technologies.

Features of Mechanical Treatment of Zirconia Crystals when Manufacturing Dies

Materials based on partially stabilized zirconia (ceramics and crystals) are distinguished by high values of mechanical strength, crack resistance, hardness, corrosion resistance, low coefficient of friction when operating in tandem with most metals, which makes them promising materials for a wide tribotechnical application in highly loaded friction units. An example of such a unit is the die mechanism, which is an integral part of the drawing die tool in the cable industry. These hard precision tools (drawing dies or wire dies) actually determine the ultimate success in the wire drawing process.

Sound-absorption and NOx-removal performances of TiO2-incorporated porous concrete made with bottom ash aggregates

The sound-absorption and NOx-removal performances of TiO2-incorporated porous concrete made with bottom ash aggregates were investigated. Concrete samples made with bottom ash aggregates having different paste-to-aggregate volume ratios (i.e., 0.2, 0.3 and 0.4) and TiO2 contents (i.e., 0%, 1% and 3%) were fabricated. The correlation between the voids and the mechanical strength values of concretes made with bottom ash aggregates was investigated through void ratio measurement and compressive strength tests to derive a proper aggregate size. The influence of target void and TiO2 content on the void ratio, compressive strength, sound-absorption, and NOx-removal performances of the samples was explored through compressive strength, void ratio, sound-absorption, and NOx-removal performance tests. The test results indicated that the sound-absorption and NOx-removal performances of the concrete samples were greatly influenced by the total void ratio, and the NOx-removal efficiency of the concrete samples was further promoted with an increase in the TiO2 content. These coupled effects were possibly attributed to the fact that the photocatalytic reaction is surface-oriented and can be affected by an increase in the total void ratio, increasing the available number of TiO2 particles on the surface that can facilitate the photocatalytic reaction when exposed to light.

MECHANICAL PROPERTIES OF POLYSULFONE-ZnO NANOCOMPOSITE MEMBRANE

Large quantities of wastewater are generated by the petroleum refining process. Micron-scale emulsion droplets and submicron droplets are difficult to remove from oil-refined wastewater, and addressing these issues has been a major challenge for researchers. Membrane technology is widely used in water treatment because it is very selective and effective in the filtration process. his research focuses on oil refinery water treatment using a polysulfone membrane (PSF)-nano-ZnO membrane with the addition of polyethylene glycol (PEG). This research aims to determine the PEG ratio that produces the optimum PSF-ZnO membrane in terms of mechanical properties, including thickness, tensile strength, and molecular weight cut-off (MWCO) value. The membranes with the optimum clearance were obtained at 3% PEG with a thickness of 0.0077 mm, Young's modulus of 8800 N/m2, and Morphological analysis was performed using the SEM (Scanning Electron Microscopy) method on the membrane which had the highest and lowest permeability values.. The best membrane MWCO value was achieved by the addition of 19% PSF-nano-ZnO 1% wt at 5 minutes of UV irradiation. This shows that the addition of PEG composite affects pore openings. The membrane formed with variations in PEG concentrations affecting the thickness of the membrane. Higher concentrations make the membrane thicker, resulting in a higher Young’s modulus.

Preloading Model on Soft Soil with Inclusion Thermal Induction Vertical and Incline Types

Soft clay has a relatively low subgrade bearing capacity. The aim is to obtain physical values, mineralogy, mechanical strength values, values for reduction. The research method used is preloading in a test tube measuring 50×70×150 cm. Each cycle of preloading and thermal induction used a fixed load of 0.015 kg/cm². Thermal induction is given vertically and obliquely with temperature variations of 100, 200, 300, and 400 °C. The main observation point is a distance of 15 cm from the center of the induction. At 400 °C inclined induction, the water content is 17.36% (from the initial water content of 59.07%), the soil cohesion is 21.75. kN/m², the value of unconfined compressive strength is 67.72 kN/m², the highest modulus of elasticity is 4593 kN/m2, and the decrease is 5.13 cm. XRD, SEM, EDS results before heating showed mineralogy 0 (65.06%), Ca (13.30%), Na (3.64%), Mg (2.15%), Al (6.63%), Si (8.52%), Sn (0.70%) and did not change significantly after heating at 400 °C. The results after heating included 0 (58.39%), Ca (14.09%), Na (0.72%), Mg (1.16%), Al (6.63%), Si (14.72%), Sn (2.54%). The novelty obtained is to change very soft conditions became medium conditions. Doi: 10.28991/cej-2021-03091705 Full Text: PDF

Comparative Modelling of Strength Properties of Hydrated-Lime Activated RiceHusk-Ash (HARHA) Modified Soft Soil for Pavement Construction Purposes by Artificial Neural Network (ANN) and Fuzzy Logic (FL)

Artificial neural network and fuzzy logic based model soft-computing techniques were adapted in the research study for the evaluation of the expansive clay soil-HARHA mixture’s consistency limit, compressibility and mechanical strength properties. The problematic clay soil was stabilized with varying proportions of HARHA (stabilizing agent) which is an agricultural waste derivative from the milling of rice ranging from 0% to 12%; the utilization of the alkaline activated wastes encourages its recycling and re-use to obtain sustainable, eco-efficient and eco-friendly engineered infrastructure for use in the construction industry with economic benefits also. The obtained laboratory and experimental responses were taken as the system database for the ANN and fuzzy logic model development; the soil-HARHA proportions with their corresponding compaction and consistency limit characteristics were feed to the network as the model input variables while the mechanical strength (California-bearing-ratio (CBR), unconfined-compressive-strength (UCS) and Resistance value (R-values)) responses of the blended soil mixture were the model target variables. For the ANN model, feed forward back propagation and Levernberg Marquardt training algorithm were utilized for the model development with the optimized network architecture of 8-6-3 derived based on MSE performance criteria; while for the fuzzy logic model, the mamdani FIS with both triangular and trapezoidal membership function with both models formulated, simulated and computed using MATLAB toolbox. The models were compared in terms of accuracy of prediction using MAE, RMSE and coefficient of determination and from the computed results, 0.2750, 0.4154 and 0.9983 respectively for ANN model while 0.3737, 0.6654 and 0.9894 respectively was obtained for fuzzy logic model. The two models displayed robust characteristics and performed satisfactorily enabling the optimization of the solid waste derivatives utilization for soil mechanical properties improvement for engineering purposes.

Effect of sonification in the alkalization process of coconut fiber to improve fiber strength

Coconut coir fiber is a natural fiber obtained from the coconut mesocarp, where in Indonesia, its utilization is still not optimal. The use of fiber as a functional material in the structural and filter requires optimal characteristics and related to lignocellulose content and modification of the fiber’s surface structure. One method of fiber modification that is mostly used is the alkalization process using NaOH solution, which aims to degrade lignin, which is rigid and brittle. This paper will discuss the effect of ultrasonic wave exposure (sonication) on alkalizing the fiber using a low concentration NaOH solution. The variation of the concentrations of NaOH solution used was 1, 3, 5, 7, and 9% with ultrasonic wave exposure for 30 minutes at temperatures of 50, 60, and 70°C. The mechanical strength of the fiber was characterized using a Thwing-Albert Testing Machine. The measurement results show that the maximum mechanical strength values obtained in the alkalization treatment for 30 minutes with a concentration of 5% NaOH solution at a temperature of 70°C is 295.13 MPa. This tensile strength increased by 68.33% compared to the untreated sample of 175.33 MPa. The strain obtained in this sample was 31.86% of the initial fiber length.

Experimental and Numerical Investigation of Sodium- and Potassium-Based Alkali Activator on the Mechanical Properties of Geopolymer-Mortars Using Lebanese Kaolin

This paper aims to study the use of Lebanese raw kaolin in the formulation of geopolymers (GP) mortars based on an experimental and numerical approach. Two classes of GP mortars were prepared: the first contained sodium (Na)-based alkali activator, while the second was prepared by adding potassium (K)-based activators. A microstructural characterization was realized before and after the calcination of the raw material. Mechanical characterization of the mortars was conducted by highlighting the impact of the two alkaline solutions used, on tests performed on days 1, 3, 7, 28, 90, and 120. Simultaneously, a three-phased heterogeneous numerical modeling (matrix, aggregates, pores) was used to obtain specific characteristics not accessible experimentally. As main results, the experimental work showed that the binding solutions’ nature and samples’ aging affected the microstructure and, consequently, the mechanical properties. K-based geopolymer mortar presents higher values of mechanical strength than Na-based geopolymer mortar. Moreover, an asymptotic behavior is observed in mechanical characteristics at about 90 days. The numerical results confirmed that micro-defects and porous network have an important impact on Young’s modulus values as well as the presence of the sand phase. The mechanical characteristics of pure binder samples were also obtained numerically. These samples contain natural defects and pores leading it impossible to obtain experimentally the desired characteristics. This work and the associated results confirm that Lebanese raw material can be considered as a sustainable construction material solution for Middle Eastern countries.

Nanofiltration membranes for salt and dye filtration: effect of membrane properties on performances.

In this study, commercial nanofiltration membranes (Toray, NF 270, Desal 5 L) were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, optical profilometry, contact angle, mechanical strength and zeta potential measurements. Filtration performance tests were conducted with distilled water, MgSO4 solution and synthetic dye solutions, respectively. Among three commercial membranes, the Toray membrane was thought to be better choice. Additional experiments were carried out for a more detailed characterization of the selected membrane. Therefore, firstly, flux and removal efficiency was monitored by using dye solutions at different pH values, and then experiments were carried out to observe the effect of different temperatures. Also, another filtration test with NaCl solution was performed for the Toray membrane. As the main purpose of this study, we aimed to establish a significant correlation between the structural properties of membranes and their performances. In light of the results obtained, it was observed that the contact angle, mechanical strength and surface roughness values of the membrane significantly affected the membrane performance. It was concluded that the most important parameter in dye removal was the zeta potential. As a result of this work, a data set of commercial membranes was created and is available to all membrane users.

Nano-platinum additives ball milled with hollow carbon spheres for mechanical tensile promotion of 2212- Pb1+x(HCNs/Pt)xBiSr2CaCu2O8 superconductor

In the present investigations platinum nano-particles in range of ≤ 20 nm were carefully ball milled with nominal composition of hollow carbon nano-spheres to apply as a softener ductile mechanical tensile promoter for 2212-PBSCCO superconductor. The samples with general formula Pb1+x(HCNs/Pt)xBiSr2CaCu2O8 where (x = 0.1,0.2 and 0.4 mol) were carefully synthesized via solid state reaction route with a certain thermal treatment cycle involving, annealing step at 865 °C for 20 h. The mechanical tensile strength measurements for the sample with x = 0.4 mol from CNs/Pt achieved maximum mechanical tensile strength value of 45.77 MPa., with promotion ratio ~ 21.08% in contrast with pure-sample x = 0 with mechanical tensile of 37.8 MPa. Furthermore, the additions of (HCNs/Pt) does not damage the whole superconductivity on the investigated range (0 ≤ x ≤ 0.4 mol). Results indicated that, the additions of (HCNs/Pt) had a remarkable, suppressing the Tc-values to Tc-offset = 62.2 K for the sample with maximum additive ratio x = 0.4 mol.