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The utilization of readily accessible natural fibres in lightweight foamed concrete (LWFC), which is already a widely used building material, can have a substantial positive impact on the environment. Therefore, the mechanical characteristics might be increased by using a correct mix proportion of fibre-reinforced LWFC. Innovative LWFC-agave fibre (AF) composites were created in this experiment. In order to get the best mechanical qualities, this investigation set out to establish the correct weight fraction of AF to be added to LWFC. Two LWFC densities of 750 and 1500 kg/m3 were produced with the addition of several weight fractions of AF, precisely 0.0%, 1.5%, 3.0%, 4.5%, 6.0%, and 7.5%, were used. To establish the mechanical characteristics of LWFCAF composites, flexural tests, tensile strength tests, axial compression tests, and ultrasonic pulse velocity tests were carried out. Test results revealed that the combination of LWFC together with a weight fraction of 4.5% of AF exhibited superior mechanical properties. Beyond 4.5% of AF's weight fraction, the mechanical properties started to deteriorate. This study gives insight and crucial data on the mechanical characteristics of LWFC-AF composites therefore it will enable future researchers to explore other properties of LWFC reinforced with AF. [ABSTRACT FROM AUTHOR]

Studying the real structure of amorphous alloys is not an easy task and requires an appropriate scientific approach. Unlike crystalline materials, for which there is a precise description of the structure based on the structure of the unit cell, in amorphous materials it is not possible to identify it. The amorphous structure is often described as one big defect. Using the technique of Mössbauer spectroscopy, it is possible to study the structure of amorphous alloys and determine the degree of their order. The paper presents the results of Mössbauer tests for amorphous alloys in the state after solidification. The influence of a small change in the chemical composition on the probability of the occurrence of iron surroundings determining specific hyperfine field induction values was determined. [ABSTRACT FROM AUTHOR]

Depending on their other constituent elements, Fe-based amorphous materials can exhibit good soft magnetic properties. By determining the directional coefficient b for the relationship of μ0M(μ0H)1/2 according to the best linear fit, it is possible to determine the parameter of spin wave stiffness Dspf. This parameter, amongst others, is related to the distribution of magnetic atoms around the central atom, which is reflected in the value of saturation magnetisation. This work has examined the structure of specially prepared alloy samples and analysed the influence of the spin wave stiffness parameter on the value of saturation magnetisation. Three alloys with different constitutions, based on the Fe matrix, were analysed. [ABSTRACT FROM AUTHOR]

The magnetization process is based on bringing about a unified arrangement of the magnetic domains. During this process, there are shifts and then the rotations of the domain walls. At a later stage, domains with a direction of magnetization that do not correlate with the applied magnetic field disappear. The turnover depends on the size of the domains. For an amorphous structure, the key factors determining the size of the magnetic domains are the distance between the magnetic atoms and the possible presence of crystalline grains. The paper presents the results of research on the influence of Cu addition on the distances between magnetic atoms and the magnetization process in high magnetic fields. The structure of the alloys was studied using X-ray diffraction. The mean grain size was estimated using the Scherrer method. The magnetic properties were determined on the basis of measurements with a vibrating magnetometer. A numerical analysis of the primary magnetization curves was performed. Despite the significant reorganization of the structure, no changes in the distance between the magnetic atoms were observed, as indicated by slight changes in the Dspf parameter. It was found that a small addition of Cu positively influences the improvement of the magnetic properties, in particular the reduction of the value of the coercive field. [ABSTRACT FROM AUTHOR]

The magnetisation process of magnetic materials is extremely important due to the potential applications of these materials. During the magnetisation process, a delay in the increase in magnetisation is observed when the magnetic field strength increases. This behaviour may be explained by the magnetic anisotropy of the studied material. The paper presents the results of research on primary magnetisation curves for magnetic alloys that exhibit soft-magnetic properties. The tested alloys are the so-called amorphous materials in which determining the preferred direction of magnetisation is difficult due to their structure. However, as our research indicates, it is in fact possible to distinguish directions of relatively easy and difficult magnetisation in amorphous materials, which implies that the phenomenon of magnetic anisotropy occurs in them. [ABSTRACT FROM AUTHOR]

Fe-based, rapid-quenched alloys are characterized by good magnetic properties. For alloys with ferromagnetic properties, an important parameter is the saturation magnetization. Its value depends on many factors, including: chemical composition, content of ferromagnetic elements, and structure of the material. For alloys with an amorphous structure, there is a chaotic arrangement of atoms in the alloy volume. Locally, however, the atoms may be in an order close to the crystal structure. The distances between magnetic atoms in such areas determine the magnetization process of the alloy. These distances can be adjusted with various alloy additions. The study investigated the effect of the content of Y and Hf on the distance between magnetic atoms and the value of saturation magnetization. It was found that a higher content of Y (characterized by a longer atomic radius compared to Hf) reduces the distance between Fe atoms and causes a decrease in the value of saturation magnetization. This is related to the local presence of antiferromagnetic order. [ABSTRACT FROM AUTHOR]

Amorphous alloys are characterized by a disordered structure. The arrangement of atoms is chaotic and it is difficult to determine the parameters describing their properties. In soft magnetic ferromagnets, one of the main parameters describing their applicability is the Curie temperature. However, in amorphous materials, due to their metastable nature, the Curie temperature occurs in a rather narrow range. Using the measurements of the magnetic saturation polarization as a function of temperature and the critical exponent β = 0.36, the value of the Curie temperature can be determined. The paper presents the results of µ0 M(T)1/β tests carried out for two amorphous alloys with similar chemical composition. The influence of chemical composition on the course of the µ0 M(T) curve and changes in the share of characteristic areas describing rearrangements of atoms in the structure of alloys were observed. [ABSTRACT FROM AUTHOR]

This paper attempts to find the possibility of describing the supplementary parameters of the macroscopic crack strength field based on the variation at the microscopic level. The analysis focuses on the development of cracks in the vicinity of the crack tip of a central crack panel made from iron material with a cubic crystal structure under tensile loading. We use the combination of finite element and molecular dynamics simulation methods. Molecular dynamics simulation analysis shows that the motion velocity of molecules near the crack tip region is less than the Rayleigh wave velocity, VR, which is about 0:22 VR. The average velocity is smaller in other directions that are not parallel to the crack. The velocity of the molecular near the crack tip indicates the ductile phenomenon of the crack tip region because it comes from the potential energy, which means that on the crack extension line, the kinetic energy of the molecular motion is greater than that in the other directions but is close to that in the 45° direction. It shows that the crack expansion direction is still mainly along the crack extension line under the load. [ABSTRACT FROM AUTHOR]

In weak magnetic fields, there are changes in the arrangement of atoms, which are otherwise called magnetic relaxations. The exact phenomenon that will be investigated in this paper concerns the disaccomodation of magnetic susceptibility, which is one of the most frequently observed effects of magnetic lag. During this magnetic delay, there is a reorientation of the axes of pairs of atoms corresponding to two different energy levels. This energy is related to the energies of exchange and spin-orbit coupling. The paper presents the results of magnetic susceptibility disaccomodation and describes its influence on the relaxation time matching spectrum. [ABSTRACT FROM AUTHOR]

Dramatic population and economic growth result in increasing demand for concrete infrastructure, which leads to an increment of freshwater demand and a reduction of freshwater resources. However, freshwater is a finite resource, which means that freshwater will be used up someday in the future when freshwater demand keeps increasing while freshwater resources are limited. Therefore, replacing freshwater with seawater in concrete blending seems potentially beneficial for maintaining the freshwater resources as well as advantageous alternatives to the construction work near the sea. There have been few experimental research on the effect of blending water salt content on the mechanical and physical characteristics of concrete, particularly high-strength concrete. Therefore, a research study on the influence of salt concentration of blending water on the physical and mechanical properties of high-strength concrete is necessary. This study covered the blending water salinity, which varied from 17.5 g/L to 52.5 g/L and was determined on the physical and mechanical properties, including workability, density, compressive strength, and flexural strength. The test results indicate that the use of sea salt in blending water had a slight negative influence on both the workability and the density of high strength concrete. It also indicates that the use of sea salt in blending water had a positive influence on both the compressive strength and the flexural strength of high-strength concrete in an earlystage. [ABSTRACT FROM AUTHOR]

To fabricate a lead-free solder with better properties, a surface-modified precipitate calcium carbonate (PCC) was added as a reinforcement phase to tin-zinc (Sn-9Zn) solder. The surface modification of PCC was done by using electroless plating to deposit nickel (Ni) layer on the PCC. Based on microstructure analysis, a thin layer of Ni was detected on the reinforcement particle, indicating the Ni-coated PCC was successfully formed. Next, composite solder of Sn-9Zn-xNi-coated PCC (x = 0, 0.25, 0.50, 1.00 wt.%) was prepared. The morphology and phase changes of the composite solder were evaluated by using optical microscope and X-ray diffraction (XRD). Significant refinement on the grain size of Zn was seen with the additions of Ni-coated PCC, with a new phase of Ni3Sn4 was detected along with the phases of Sn and Zn. The wettability of Sn-9Zn was also improved with the presence of Ni-coated PCC, where the wetting angle decreased from 28.3° to 19.4-23.2°. Brinell hardness test revealed up to 27.9% increase in hardness for the composite solder than the pristine Sn-9Zn solder. This phenomenon contributed by the increased in dislocation resistance through Zener pinning effect and Zn grain refinement within the composite solder which enhanced the overall properties of the composite solder. [ABSTRACT FROM AUTHOR]

The composition and structural modification of aluminium alloys influence their strength, tribological properties and structural stability. The phase composition of the structure as well as the characteristics of the elementary cell of each identified phase was established by X-ray diffraction, and the main objective was to determine the compositional phases, microstructure and microcomposition of the alloy. Based on the cyclic voltammograms it can be said that on the OCP interval (+1.5 V... -1.1 V), after the breakthrough potential is an intensification of the anodic process by the pronounced increase of the current density, in these conditions the Al-Si alloy has low values which means that it has a better corrosion resistance. [ABSTRACT FROM AUTHOR]

Filler surface modification has become an essential approach to improve the compatibility problem between natural fillers and polymer matrices. However, there is limited work that concerns on this particular effect under dynamic loading conditions. Therefore, in this study, both untreated and treated low linear density polyethylene/rice husk composites were tested under static (0.001 s-1, 0.01 s-1 and 0.1 s-1) and dynamic loading rates (650 s-1, 900 s-1 and 1100 s-1) using universal testing machine and split Hopkinson pressure bar equipment, respectively. Rice husk filler was modified using silane coupling agents at four different concentrations (1, 3, 5 and 7% weight percentage of silane) at room temperature. This surface modification was experimentally proven by Fourier transform infrared and Field emission scanning electron microscopy. Results show that strength properties, stiffness properties and yield behaviour of treated composites were higher than untreated composites. Among the treated composites, the 5% silane weight percentage composite shows the optimum mechanical properties. Besides, the rate of sensitivity of both untreated and treated composites also shows great dependency on strain rate sensitivity with increasing strain rate. On the other hand, the thermal activation volume shows contrary trend. For fracture surface analysis, the results show that the treated LLDPE/RH composites experienced less permanent deformation as compared to untreated LLDPE/RH composites. Besides, at dynamic loading, the fracture surface analysis of the treated composites showed good attachment between RH and LLDPE. [ABSTRACT FROM AUTHOR]

Microstructures are an important link between materials processing and performance, and microstructure control is essential for any materials processing route where the microstructure plays a major role in determining the properties. in this work, silverdoped titanium dioxide (Ag/Tio2) thin film was prepared by the sol-gel method through the hydrolysis of titanium tetra-isopropoxide and silver nitrate solution. the sol was spin coated on ito glass substrate to get uniform film followed by annealing process for 2 hours. the obtained films were annealed at different annealing temperatures in the range of 300°C-600°C in order to observe the effect on crystalline state, microstructures and optical properties of Ag/Tio2 thin film. the thin films were characterized by X-Ray diffraction (XRD), scanning electron microscopy (sem), and uV-Vis spectrophotometry. it is clearly seen, when the annealing temperature increases to 500°C, a peak at 2θ = 25.30° can be seen which refers to the structure of TiO2 tetragonal anatase. the structure of Ag/Tio2 thin film become denser, linked together, porous and uniformly distributed on the surface and displays the highest cut-off wavelength value which is 396 nm with the lowest band gap value, which is 3.10 eV. [ABSTRACT FROM AUTHOR]

The increasing needs of using aluminum epoxy composite as a replacement to solid metal rapid prototyping has opened to interests in optimizing its machining processes. This paper reported on the success of optimizing the surface roughness of aluminium epoxy composite using milling process along with a new finding on the best combination parameters. taguchi method was used as The optimization method whereas spindle speed, feed rate, and depth of cut were set as input factors using an L9 orthogonal array. Analysis of Variance was used to identify the significant factors influencing the surface roughness. Experiment was conducted in dry condition using a vertical milling machine and the surface roughness after the machining was evaluated. Optimum combination of cutting parameters was identified after the finest surface roughness (response) based on the signal-to-noise ratio calculated. Cutting parameters selected after preliminary testing are cutting speeds of (2000, 3000 and 4000) rpm, feed rate (300, 400 and 500) mm/min, and cutting depth (0.15, 0.20, and 0.25) mm. The result showed that cutting speed had the largest percentage contribution to surface roughness with 69% and the second highest contribution was feed rate with 22% and depth of cut at 9%. the spindle speed was found as the most significant factor influencing the quality of surface roughness. the result is significant particularly in providing important guidelines for industries in selecting the right combination of parameters as well as to be cautious with the most significant factor affecting the milling process of metal epoxy composite. [ABSTRACT FROM AUTHOR]

The disposal of industrial steel mill sludge in landfills has frequently received significant concern as the sludge has a very notable potential to contaminate soil surface and groundwater in the long run. recently, the incorporation of industrial steel mill sludge into fired clay brick has become one of the promising alternative methods as it could produce a lightweight product while minimizing the environmental impact of the waste used. in this study, fired clay bricks as the most common building material were incorporated with 0%, 5%, 10% and 15% of steel mill sludge and fired at 1050°C (heating rate of 1°C/min). the manufactured bricks were subjected to physical and mechanical properties such as firing shrinkage, dry density, and compressive strength while the toxicity Characteristic leaching Procedure (tClP) was conducted to analyze leaching behavior from the manufactured bricks. the results demonstrated that incorporation up to 15% of steel mill sludge reduces the properties up to 27.3% of firing shrinkage, 8.1% of dry density and 67.3% of compressive strength. the leaching behavior of zn and Cu from steel mill sludge was reduced up to 100% from 7414 to 9.22 ppm (zn) and 16436 to 4.654 ppm (Cu) after 15% of sludge incorporation. it was observed that high temperature during the firing process would improve the properties of bricks while immobilizing the heavy metals from the waste. therefore, recycling steel mill sludge into construction building materials could not only alleviate the disposal problems but also promote alternative new raw materials in building industries. [ABSTRACT FROM AUTHOR]

In this globalized era, building materials play an essential role in the civil engineering field. nowadays, with the increase in population, the demand for construction activities is also increasing. Polyethylene (Pet) bottles are among the most widely used materials and cause an abundance of non-degradable waste, at about 0.94 million tonnes in Malaysia. one of the alternatives to reduce this waste's environmental impact is to incorporate it inside building materials such as brick and concrete. as Pet bottles' recycling is highly promoted, the physical and mechanical properties of building materials made from Pet bottles have also been reviewed. the data analysis shows that the compressive strength, flexural strength, split tensile strength and density of building materials decreases as the percentage of Pet waste increases. however, other properties such as water absorption, initial absorption rate, and firing shrinkage increase proportionally with the Pet waste. besides, heavy metals in these building materials comply with the united states environmental Protection agency (usePa) standards. It can be concluded that the percentage of Pet waste incorporated into brick and concrete must be less than 5% and 2%, respectively, to produce suitable materials to provide alternatives in reducing and recycling Pet waste. [ABSTRACT FROM AUTHOR]

Generally speaking, the structure of amorphous alloys can be difficult to describe accurately. The absence of repeating arrangements of atoms within the volume of the alloy generates unique material properties, but at the same time makes it difficult to describe the structure systematically. One of the exceptions to this rule is the class of amorphous alloys that exhibit ferromagnetic properties. The structure of these alloys can be assessed, in an indirect way, using the sensitivity of the magnetisation vector to any inhomogeneities in their volume. This paper presents the results of indirect structural research in accordance with the assumptions of H. Kronmüller’s theory. The Fe61+xCo10−xY8W1B20 alloys — with variable Co and Fe content— were investigated. The alloy samples were made using the injection-casting method. The structure of each of the produced materials was investigated using X-ray diffraction and by examining indirectly the course of the magnetisation process in the area known as the approach to ferromagnetic saturation. In the case of the tested alloys, it was found that the magnetisation process is related to the rotation of the magnetisation vector around linear defects. [ABSTRACT FROM AUTHOR]

As part of this work, structural investigations were carried out on rapidly-cooled alloys with the following chemical compositions: Fe60Co10Y8-xNi2+xB20 (where x = 0, 1). X-ray diffraction studies confirmed that the tested materials have an amorphous structure. This structure is characterized by absence of long-range atomic order, in the contexts of angularity and periodicity. Therefore, these materials should exhibit different magnetic properties, compared with those of their crystalline counterparts. In the electrical power and electronics industries, there is a constant demand for materials with better and better properties. The main considerations of applicability are economics and environmental protection. The deciding parameter, determining the usefulness of ferromagnetic alloys in electrotechnical devices and considering economics and ecology, is their low losses on remagnetization. For the produced alloys, described in this paper, a series of loss tests for remagnetization at different frequencies was carried out. The losses for remagnetization -- pertaining to the hysteresis loop -- and additional losses were determined. [ABSTRACT FROM AUTHOR]

Remagnetisation losses are one of the most important performance parameters of materials designed for the production of low-loss transformer cores. Classical Fe–Si alloys are characterised by losses of a few W/kg. However, the crystal structure makes these materials unsuitable for use at high frequencies. The ferromagnetic Fe-based alloys constitute an interesting group of alloys with magnetic soft properties. This group includes alloys from the Fe–Me–B system (where Me is one of the range of transition metals). This study investigates the structure, and losses due to remagnetisation, of bulk amorphous FeYMoNbB-based alloys. It was found that the addition of a small quantity of Nb changes the structure, and the magnitude of the losses. The addition of Nb significantly reduces additional losses; this effect is associated with the changing melt viscosity. [ABSTRACT FROM AUTHOR]

The paper deals with a study and comparison between welding with several wires in different shielding atmospheres and single-wire welding. The first part treats the equipment for multiple-wire electrode welding and a comparison between single-wire welding and twin-wire welding. The second part deals with the melting rate as a basis for determining the productivity of welding processes, and the third one with the energy efficiency as a criterion of cost-effectiveness of welding. Some results obtained regarding strength of submerged arc welded joints are shown.

Water contamination is a major issue due to industrial releases of hazardous heavy metals. Copper ions are among the most dangerous heavy metals owing to their carcinogenicity and harmful effects on the environment and human health. Adsorption of copper ions using alkali activated materials synthesized through the polycondensation reaction of an alkali source and aluminosilicates is the most promising technique, and has a high adsorption capability owing to a large surface area and pore volume. This research focuses on the effect of the alkaline activator ratio, which is a sodium silicate to sodium hydroxide ratio. Various exposing temperatures on metakaolin based alkali activated materials on a surface structure with excellent functional properties can be used as adsorbent materials for the removal of copper ions. A variety of mix designs were created with varying sodium silicate to sodium hydroxide ratios, with a fixed sodium hydroxide molarity, metakaolin to alkali activator ratio, hydrogen peroxide, and surfactant content of 10 M, 0.8, 1.00 wt%, and 3.0 wt%, respectively. Most wastewater adsorbents need high sintering temperatures, requiring an energy-intensive and time-consuming manufacturing process. In this way, metakaolin-based alkali activated materials are adsorbent and may be produced easily by solidifying the sample at 60 °C without using much energy. The specific surface area, water absorption, microstructure, phase analysis, functional group analysis, and adsorption capability of copper ions by metakaolin based alkali activated materials as adsorbents were evaluated. The water absorption test on the samples revealed that the sodium silicate to sodium hydroxide 0.5 ratio had the highest water absorption percentage of 36.24%, superior pore size distribution, and homogeneous porosity at 60 °C, with a surface area of 24.6076 m 2 /g and the highest copper ion uptake of 63.726 mg/g with 95.59% copper ion removal efficiency at adsorption condition of pH = 5, a dosage of 0.15 g, 100 mg/L of the initial copper solution, the temperature of 25 °C, and contact time of 60 min. It is concluded that self-supported metakaolin based alkali activated material adsorbents synthesized at low temperatures effectively remove copper ions in aqueous solutions, making them an excellent alternative for wastewater treatment applications.

There is a burgeoning interest in the development of geopolymers as sustainable construction materials and incombustible inorganic polymers. However, geopolymers show quasi-brittle behavior. To overcome this weakness, hundreds of researchers have focused on the development, characterization, and implementation of geopolymer-reinforced fibers for a wide range of applications for light geopolymers concrete. This paper discusses the rapidly developing geopolymer-reinforced fibers, focusing on material and geometrical properties, numerical simulation, and the effect of fibers on the geopolymers. In the section on the effect of fibers on the geopolymers, a comparison between single and hybrid fibers will show the compressive strength and toughness of each type of fiber. It is proposed that interfacial bonding between matrix and fibers is important to obtain better results, and interfacial bonding between matrix and fiber depends on the type of material surface contact area, such as being hydrophobic or hydrophilic, as well as the softness or roughness of the surface.

The demand for natural fiber hybrid composites for various applications has increased, which is leading to more research being conducted on natural fiber hybrid composites due to their promising mechanical properties. However, the incompatibility of natural fiber with polymer matrix limits the performance of the natural fiber hybrid composite. In this research work, the mechanical properties and fiber-to-matrix interfacial adhesion were investigated. The efficiency of methyl methacrylate (MMA)-esterification treatments on composites' final product performance was determined. The composite was prepared using the hand lay-up method with varying kenaf bast fiber (KBF) contents of 10, 15, 20, 25, 30, 35 (weight%) and hybridized with glass fiber (GF) at 5 and 10 (weight%). Unsaturated polyester (UPE) resin and methyl ethyl ketone peroxide (MEKP) were used as binders and catalysts, respectively. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) were used to examine the effects of MMA-esterification treatment on tensile strength and morphology (tensile fracture and characterization of MMA-esterification treatment) of the composite fabricated. The tensile strength of MMA-treated reinforced UPE and hybrid composites are higher than that of untreated composites. As for MMA treatment, 90 min of treatment showed the highest weight percent gain (WPG) and tensile strength of KBF-reinforced UPE composites. It can be concluded that the esterification of MMA on the KBF can lead to better mechanical properties and adhesion between the KFB and the UPE matrix. This research provides a clear reference for developing hybrid natural fibers, thus contributing to the current field of knowledge related to GF composites, specifically in transportation diligences due to their properties of being lightweight, superior, and involving low production cost.

Thermal performance, combustibility, and fire propagation of fly ash-metakaolin (FA-MK) blended geopolymer with the addition of aluminum triphosphate, ATP (Al(H 2 PO 4 ) 3 ), and monoaluminium phosphate, MAP (AlPO 4 ) were evaluated in this paper. To prepare the geopolymer mix, fly ash and metakaolin with a ratio of 1:1 were added with ATP and MAP in a range of 0-3% by weight. The fire/heat resistance was evaluated by comparing the residual compressive strengths after the elevated temperature exposure. Besides, combustibility and fire propagation tests were conducted to examine the thermal performance and the applicability of the geopolymers as passive fire protection. Experimental results revealed that the blended geopolymers with 1 wt.% of ATP and MAP exhibited higher compressive strength and denser geopolymer matrix than control geopolymers. The effect of ATP and MAP addition was more obvious in unheated geopolymer and little improvement was observed for geopolymer subjected to elevated temperature. ATP and MAP at 3 wt.% did not help in enhancing the elevated-temperature performance of blended geopolymers. Even so, all blended geopolymers, regardless of the addition of ATP and MAP, were regarded as the noncombustible materials with negligible (0-0.1) fire propagation index.

Concrete mix design and the determination of concrete performance are not merely engineering studies, but also mathematical and statistical endeavors. The study of concrete mechanical properties involves a myriad of factors, including, but not limited to, the amount of each constituent material and its proportion, the type and dosage of chemical additives, and the inclusion of different waste materials. The number of factors and combinations make it difficult, or outright impossible, to formulate an expression of concrete performance through sheer experimentation. Hence, design of experiment has become a part of studies, involving concrete with material addition or replacement. This paper reviewed common design of experimental methods, implemented by past studies, which looked into the analysis of concrete performance. Several analysis methods were employed to optimize data collection and data analysis, such as analysis of variance (ANOVA), regression, Taguchi method, Response Surface Methodology, and Artificial Neural Network. It can be concluded that the use of statistical analysis is helpful for concrete material research, and all the reviewed designs of experimental methods are helpful in simplifying the work and saving time, while providing accurate prediction of concrete mechanical performance.

Many studies have been done using recycled waste materials to minimise environmental problems. It is a great opportunity to explore mechanical recycling and the use of recycled and virgin blend as a material to produce new products with minimum defects. In this study, appropriate processing parameters were considered to mould the front panel housing part using R0% (virgin), R30% (30% virgin: 70% recycled), R40% (40% virgin: 60% recycled) and R50% (50% virgin: 50% recycled) of Polycarbonate (PC). The manufacturing ability and quality during preliminary stage can be predicted through simulation analysis using Autodesk Moldflow Insight 2012 software. The recommended processing parameters and values of warpage in x and y directions can also be obtained using this software. No value of warpage was obtained from simulation studies for x direction on the front panel housing. Therefore, this study only focused on reducing the warpage in the y direction. Response Surface Methodology (RSM) and Genetic Algorithm (GA) optimisation methods were used to find the optimal processing parameters. As the results, the optimal ratio of recycled PC material was found to be R30%, followed by R40% and R50% materials using RSM and GA methods as compared to the average value of warpage on the moulded part using R0%. The most influential processing parameter that contributed to warpage defect was packing pressure for all materials used in this study.

Geopolymer concrete has the potential to replace ordinary Portland cement which can reduce carbon dioxide emission to the environment. The addition of different amounts of steel fibers, as well as different types of end-shape fibers, could alter the performance of geopolymer concrete. The source of aluminosilicate (fly ash) used in the production of geopolymer concrete may lead to a different result. This study focuses on the comparison between Malaysian fly ash geopolymer concrete with the addition of hooked steel fibers and geopolymer concrete with the addition of straight-end steel fibers to the physical and mechanical properties. Malaysian fly ash was first characterized by X-ray fluorescence (XRF) to identify the chemical composition. The sample of steel fiber reinforced geopolymer concrete was produced by mixing fly ash, alkali activators, aggregates, and specific amounts of hook or straight steel fibers. The steel fibers addition for both types of fibers are 0%, 0.5%, 1.0%, 1.5%, and 2.0% by volume percentage. The samples were cured at room temperature. The physical properties (slump, density, and water absorption) of reinforced geopolymer concrete were studied. Meanwhile, a mechanical performance which is compressive, as well as the flexural strength was studied. The results show that the pattern in physical properties of geopolymer concrete for both types of fibers addition is almost similar where the slump is decreased with density and water absorption is increased with the increasing amount of fibers addition. However, the addition of hook steel fiber to the geopolymer concrete produced a lower slump than the addition of straight steel fibers. Meanwhile, the addition of hook steel fiber to the geopolymer concrete shows a higher density and water absorption compared to the sample with the addition of straight steel fibers. However, the difference is not significant. Besides, samples with the addition of hook steel fibers give better performance for compressive and flexural strength compared to the samples with the addition of straight steel fibers where the highest is at 1.0% of fibers addition.

This paper presents the results of an investigation into rapidly quenched Fe-based alloys with the chemical formula: Fe 61 Co 10 B 20 W 1 Y 8-x Pt x (where x = 3, 4, 5). In these alloys, a small quantity of Pt was added, and the Y content was reduced concurrently. Samples of the aforementioned alloys were injection-cast in the form of plates with the dimensions: 0.5 mm × 10 mm × 10 mm. The resulting structure was examined using X-ray diffractometry (XRD), Mössbauer spectroscopy and scanning electron microscopy (SEM). The results of the structural research reveal that, with a small addition of Pt, areas rich in Pt and Y are created-in which Fe-Pt and Pt-Y compounds, with different crystallographic systems, are formed. It has also been shown that an increase in Pt content, at the expense of Y, contributed to the formation of fewer crystalline phases, i.e., it allowed a material with a more homogeneous structure to be obtained. Magnetic properties of the Fe 61 Co 10 B 20 W 1 Y 8-x Pt x (where x = 3, 4, 5) alloy samples were tested using a vibrating sample magnetometer (VSM). The magnetic properties of the investigated materials revealed that the saturation magnetisation increased with increasing Pt content, at the expense of Y. This effect is due to the occurrence of different proportions of crystalline magnetic phases within the volume of each alloy.

The structure of amorphous alloys still has not been described satisfactorily due to the lack of direct methods for observing structural defects. The magnetizing process of amorphous alloys is closely related to its disordered structure. The sensitivity of the magnetization vector to any heterogeneity allows indirect assessment of the structure of amorphous ferromagnetic alloys. In strong magnetic fields, the magnetization process involves the rotation of a magnetization vector around point and line defects. Based on analysis of primary magnetization curves, it is possible to identify the type of these defects. This paper presents the results of research into the magnetization process of amorphous alloys that are based on iron, in the areas called the approach to ferromagnetic saturation and the Holstein-Primakoff para-process. The structure of a range of specially produced materials was examined using X-ray diffraction. Primary magnetization curves were measured over the range of 0 to 2 T. The process of magnetizing all of the tested alloys was associated with the presence of linear defects, satisfying the relationship D di p < 1 H . It was found that the addition of yttrium, at the expense of hafnium, impedes the magnetization process. The alloy with an atomic content of Y = 10% was characterized by the highest saturation magnetization value and the lowest value of the D spf parameter, which may indicate the occurrence of antiferromagnetic ordering in certain regions of this alloy sample.