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This study aims to investigate the dielectric response of the porous hydroxyapatite/starch composites by varying the starch proportion in determining the feasibility of the microwave sample characterization technique in bone tissue engineering. The porous hydroxyapatite/starch composites were fabricated by using natural starch (gelatinization and retrogradation) through the solvent casting and particulate leaching technique. The dielectric constant (ε′) and loss factor (ε′′) of the complex permittivity of the porous hydroxyapatite/starch composites were measured in the Ku band frequency of 12.4-18.0 GHz. ε′ and ε′′ of the porous composites increase with frequency. The highly porous composite that due to higher starch proportion exhibit higher ε′ and ε′′, resulting in the significant dielectric responses.

This study focuses on the synthesis of synthetic calcium monosilicate ceramic from chicken eggshells and rice husks waste through the mechanochemical route that relatively straightforward without adding any binders. Synthetic calcium monosilicate was mixed using a 1:1 ratio of calcined eggshell and rice husk ash, which both materials known as rich in calcium oxide and silica sources, respectively. The mixed powder was pressed using uniaxial pressing before fired at 1100°C, 1150°C, 1200°C, 1250°C, and 1300°C for 120 minutes with a heating rate of 5°C/min. The XRD spectrum from 1100°C to 1200°C mainly consists of pseudowollastonite (ICSD: 98-005-2576), wollastonite and silicon dioxide phases. However, as the sintering temperature increases, the wollastonite phases was completely transformed into pseudowollastonite, leaving some unreacted silica.

In this paper, tricalcium disilicate was formed from dicalcium silicate compound powder, synthesised via a mechanochemical technique using a stoichiometric 2CaO:1SiO2. Compound CaO and SiO2 were derived from the bio-waste of eggshell and rice husk at the calcination temperature of 900°C and 800°C, respectively. The dicalcium disilicate powder was sintered for 2 hours at different temperatures ranging from 1150°C to 1350°C. Using X-ray diffraction with Rietveld analysis, it was found that the amount of tricalcium disilicate with monoclinic (beta) crystal structure increases on sintering temperature at the expense of dicalcium silicate. The complete formation of single-phase tricalcium disilicate began at a sintering temperature of 1300°C. The effect of sintering temperatures on the crystallisation and phase transition of dicalcium silicate is reported. The size of crystallites depends on the sintering temperature. The finding of this study rebound to the benefit of society by reducing the risk-off pollution cause by accessive redundant bio-waste eggshell and rice husk and also reduced the amount of CaO and SiO2 used in the fabrication of Ca3Si2O7.

The porcelain formulation containing percentages of treated FGD sludge waste from 5% up to 15% in replacement of feldspar were prepared. The porcelain mixture formulation were mixed by high energy planatery mill at speed 300 rpm for 1 hours. The powder were compacted by using hydraulic press and sintered at temperature 1200 °C for 3 hours. The sintered samples were characterized using X-ray fluorescene (XRF), X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) and Thermogravimetry/Differential scanning calorimetry (TGA/DCS). The primary effect concerning the addition of treated FGD sludge was the change of intensity composition (gypsum and anhydrate) in porcelain formulation. The XRD analysis has shown that the main component in sludge waste were gypsum and anhydrate.

Flue Gas Desulfurization (FGD) is a waste incineration process commonly used to eliminate sulfur dioxide (SO2) from flue gas power plants. FGD by-product recorded a rich gypsum content, also known as calcium sulfate dehydrate (CaSO4•2H2O), which has promising practical applications in plaster mould production. Plaster of Paris (POP) with a chemical composition of calcium sulfate hemihydrate (CaSO4•0.5H2O) is widely used in plaster mould production because of its quick setting and hardening upon moistened. Naturally, gypsum with 2 molecules of crystalline water can change to 1.5 molecules via the dehydration process. Various dehydration methods were conducted to transform FGD gypsum to hemihydrate. After undergoing different autoclave processes, the phase transition of FGD by-products was identified by X-ray diffraction (XRD) mode and compared with commercial POP. Chemical composition of FGD sludge contains a high amount of calcium oxide (CaO), sulfur trioxide (SO3) and boron trioxide (B2O3), as well as other impurities such as fluorine (F), chlorine (Cl), and magnesium oxide (MgO). Based on phase analysis, sample H1 to H5 show the percentage of hemihdyrate is 1.5%, 19.7%, 2.8%, 1.2%, and 46.1%, respectively, after different dehydration methods.

This study aims to investigate the electromagnetic properties of a composite of hardened glass particle and carbon using resin in determining the absorbability of the composite for electromagnetic interference (EMI). The electromagnetic absorption measurement was conducted using T-R method (transmission-reflection) by measuring the dielectric constant, loss factor, real and imaginary part of permeability, reflection coefficient and transmission coefficient. The measurement is taken for X band frequency and Ku band frequency within the frequency range from 8.2GHz to 12.4GHz and 12.4GHz to 18GHz, respectively. Dielectric constant of sample decrease when frequency increases. The high dielectric constant of material implies that the material has high absorbability of field energy, resulting in high attenuation of the applied field.