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A new transparent zinc silicate glass-ceramic was derived from the 55ZnO–5B2O3–40SLS glass system via a controlled heat-treatment method. The precursor glass sample was placed through the heat-treatment process at different temperatures to study the progress in phase transformation, optical performance and emission intensity of the zinc silicate glass-ceramics. For this project, material characterization was measured through several tests using densimeter and linear shrinkage measurement, X-ray diffraction (XRD), Fourier transform infrared reflection (FTIR), ultraviolet–visible (UV–Vis) and photoluminescence (PL) spectroscopy. The density and linear shrinkage measurements show that the density of the particular glass-ceramic samples increases with the progression of heating temperature. The XRD analysis displays the result in which the zinc silicate crystal starts to grow after the sample was treated at 700 °C. In addition, the FTIR spectra indicated that the crystallization of the zinc silicate phase occurred with the appearance of SiO4, ZnO4 and Si-O-Zn bands. UV–visible exhibited the small changes when the value for the optical band gap decreased from 3.867 to 3.423 eV, influenced by the temperature applied to the sample. Furthermore, the PL spectroscopy showed an enhancement of broad green emission at 534 nm upon the increased heat-treatment temperature. Thus, it can be concluded there is the progression of crystal growth as the heat-treatment temperature increased; three emission peaks appeared at 529, 570 and 682 nm for the green, yellow and red emissions, respectively.

A simple and sensitive aptasensor based on conductive carbon nanodots (CDs) was fabricated for the detection of 17ß-Estradiol (E2). In the present study, the hydrothermal synthesis of carbon nanodots was successfully electrodeposited on a screen-printed electrode (SPE) as a platform for immobilization of 76-mer aptamer probe. The morphology and structure of the nanomaterial were characterized by UV-visible absorption spectra, Fluorescence spectra, Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). Moreover, cyclic voltammetry and electrochemical impedance spectroscopy were used to investigate the electrochemical performance of the prepared electrodes. Subsequently, impedimetric (EIS) measurements were employed to investigate the relative impedances changes before and after E2 binding, which results in a linear relationship of E2 concentration in the range of 1.0 × 10−7 to 1.0 × 10 −12 M, with a detection limit of 0.5 × 10−12 M. Moreover, the developed biosensor showed high selectivity toward E2 and exhibited excellent discrimination against progesterone (PRG), estriol (E3) and bisphenol A (BPA), respectively. Moreover, the average recovery rate of spiked river water samples with E2 ranged from 98.2% to 103.8%, with relative standard deviations between 1.1% and 3.8%, revealing the potential application of the present biosensor for E2 detection in water samples.

In this research, influence of zinc oxide (ZnO) addition in silica matrix to produce zinc silicate glass system (ZnO–SiO2) derived from white rice husk ash (WRHA) have been investigated via solid state method. The 90 wt percentage (wt.%) of silica content in WRHA has been proved by X-ray fluorescence spectroscopy (XRF). Hence, the compositions of (ZnOx–WRHA1-x) glass system were varied by x = 0.50, 0.55, 0.60, 0.65 and 0.70 wt% to study their structural and optical behaviors. The X-ray diffraction (XRD) patterns revealed that with the addition of ZnO in the silica matrix, the broad halo peaks became weaker and caused a few crystalline peaks to appear. Meanwhile, Fourier transform infrared spectroscopy (FTIR) revealed that absorption bands related to SiO4 unit group are weakened as amount of ZnO increased. This is due to the increase of non-bridging oxygen's (NBO's) formation in the glass structure which also affects the absorbance measurement by ultra violet visible spectroscopy (UV–Vis) to be shifted towards higher in wavelength as the composition of ZnO increases. Lattice distortion due to NBO's formation had decreased the band gap values from 4.28 eV to 3.95 eV. Overall, 60:40 ratio of ZnO against WRHA was selected as the best ratio to produce zinc silicate (Zn2SiO4) glass ceramics. Lastly, the characterization of europium (Eu3+) doped Zn2SiO4 glass ceramics with subject to sintering temperature also has been studied to prove that this material can be a great potential host matrix for red-emitting phosphor.

The alumino-silicate-fluoride (ASF) bioglass system with empirical formula [(45-x)SiO2-xCaF2-20P2O5-20Al2O3-15CaO] where x = 5, 10, 15, and 20 (wt.%) has been synthesised by using conventional melt-quenching method. In this study, soda lime silica (SLS) glass and clam shell (CS) vitreous waste were utilized as a source of silicon dioxide (SiO2) and calcium oxide (CaO), respectively. The different physical behaviors of ASF bioglass were closely related to the CaF2 content in each composition. The structural analysis shows the presence of various chemical bonds showing the formation of ASF bioglass. The ASF bioglass has many applications in dental field and efforts to improve its formulation can promise a better future in medical procedures.

For the very first time, a study on the crystallization growth of zinc silicate glass and glass-ceramics was done, in which white rice husk ash (WRHA) was used as the silicon source. In this study, zinc silicate glass was fabricated by using melt–quenching methods based on the composition (ZnO)0.55(WRHA)0.45, where zinc oxide (ZnO) and white rice husk ash were used as the raw materials. The control crystallization technique was used in which the sample was sintered at 700–950 °C; then, the physical, structural, and optical properties of the glass and glass-ceramics were investigated by using a densitometer, linear shrinkage, X-ray diffraction (XRD), Fourier transform infrared radiation (FTIR), field-emission scanning electron microscopy (FESEM), and photoluminescence spectroscopy (PL). The density and linear shrinkage increased as the crystallinity increased and the XRD results showed the progression of the crystal formation, in which the sample was still in an amorphous state at 27 °C and 700 °C; the crystalline phase started at 750 °C. Based on the FTIR spectra, all samples showed sharpened absorption bands as the sintering temperature was increased, and the FESEM image showed the progression of crystal growth, indicating the formation of zinc silicate glass-ceramics. Lastly, the PL spectra emitted three emission peaks, at 529, 570, and 682 nm for the green, yellow, and red emission, respectively.

Death from tuberculosis has resulted in an increased need for early detection to prevent a tuberculosis (TB) epidemic, especially in closed and crowded populations. Herein, a sensitive electrochemical DNA biosensor based on functionalized iron oxide with mercaptopropionic acid (MPA-Fe3O4) nanoparticle and nanocellulose crystalline functionalized cetyl trimethyl ammonium bromide (NCC/CTAB) has been fabricated for the detection of Mycobacterium tuberculosis (MTB). In this study, a simple drop cast method was applied to deposit solution of MPA-Fe3O4/NCC/CTAB onto the surface of the screen-printed carbon electrode (SPCE). Then, a specific sequence of MTB DNA probe was immobilized onto a modified SPCE surface by using the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) coupling mechanism. For better signal amplification and electrochemical response, ruthenium bipyridyl Ru(bpy)32+ was assigned as labels of hybridization followed by the characteristic test using differential pulse voltammetry (DPV). The results of this biosensor enable the detection of target DNA until a concentration as low as 7.96 × 10−13 M with a wide detection range from 1.0 × 10−6 to 1.0 × 10−12 M. In addition, the developed biosensor has shown a differentiation between positive and negative MTB samples in real sampel analysis.

This work focused on the influence of carbon nanotubes(CNT)to the microstructural properties of Zn2SiO4/CNT (ZSO/CNT) composite. CNT was synthesized via alcohol catalytic chemical vapor deposition (ACCVD) using cobalt oxide as catalyst and ethanol as carbon source. Zinc silicate (ZSO)glass was prepared from quenching the melted commercial waste glass bottle with zinc oxide powder. ZSO/CNT-x composites with various CNT concentration (0, 1, 2 and 3 wt%)was prepared through introducing CNT into ZSO glass via dry processing technique followed by sintering process in Argon gas(Ar) environment and atmospheric (atm) environment, respectively. FESEM, XRD and EDS were employed to determine the surface morphology, phase composition and elemental distribution of sintered sample. Crystallite trigonal willemite (Zn2SiO4) phase was observed from argon sintered sample and the crystallite size of willemite phase in ZSO/CNT-3/Ar showed the most reduced lattice strain of 22.85% compared to ZSO/CNT-0/Ar. In contrast, semi crystalline phase exhibited in atmospheric sintered sample resulted in high lattice strain. It is concluded that dry powder processing and inert gas thermal treatment can be an effective technique in fabricating strain-reduced ceramics/ CNT composite without alternating the domain phase. Least internal strain in crystal lattice have potential on enhancing the luminescence properties of phosphor material and lattice thermal conductivity of thermoelectric material.

In this paper, the ZnO–SiO2 was synthesized using ZnO nanopowders and SiO2 developed from coconut husk ash by using conventional solid state method. The ZnO–SiO2 crystal system was heat-treated and the properties was studied. The XRD results showed high intensity peaks due to its high crystallinity when sintered at high temperature. The morphological differences can also be observed through FESEM images as the heat-treated crystal system showed well-distinct boundaries. Meanwhile, the absorbance intensity decreased and shifted to the lower wavelength after heat-treated. The optical band gap value of the ZnO–SiO2 was 3.22 eV before treated and increased to 4.05 eV after heat treated. The presented results showed good properties of zinc silicate and it has a great potential as phosphors in optical application.

Artificial neural networks (ANN) is known as one of the artificial intelligence tools which are inspired by the biological nerve system, have a capability to predict the physical and elastic parameter of glasses without melting the raw materials. The experimental of bismuth-tellurite glasses with the composition yBi2O3 - (1-y)TeO2 where y = 0, 0.05, 0.07, 0.10, 0.13, 0.15 have been fabricated using melting and quenching methods. These works were discovered that the prediction value by artificial neural networks for density, ultrasonic velocity, and elastic moduli of bismuth-tellurite glass composition gives a very good agreement as compared with the experimental measurements. The goodness of fit from the graph used R2 value to represent the relationship between the data presented from the experiment and prediction model. The great fit of coefficient R2 value elucidates in all figures is around 0.99942–1.0000 which is considered to be very satisfactory.

In this study, a series of Li2O-Al2O3-B2O3 glasses doped with various concentrations of Dy2O3 (where x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0 mol%) were prepared by using a conventional melt-quenching technique. The structural, physical and optical properties of the glasses were examined by utilising a variety of techniques instance, X-ray diffraction (XRD), UV–Vis-NIR spectrometer, Fourier transform infrared (FTIR) and photoluminescence (PL). The XRD spectra demonstrate the amorphous phase of all glasses. Furthermore, the UV-vis-NIR spectrometers have registered optical absorption spectra a numbers of peaks which exist at 1703, 1271, 1095, 902, 841, 802, 669, 458, 393 and 352 nm congruous to the transitions from the ground of state (6H15/2) to different excited states, 6H11/2, 6F11/2 + 6H9/2, 6F9/2 + 6H7/2, 6F7/2, 6F5/2, 6F3/2, 4F9/2, 4I15/2, 4F7/2 and 6P7/2, respectively. The spectra of emission exhibit two strong emanation bands at 481 nm and 575 nm in the visible region, which correspond to the transitions 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2. All prepared glass samples doped with Dy2O3 show an increase in the emission intensity with an increase in the concentration of Dy3+. Based on the obtained results, the aforementioned glass samples may have possible applications, such as optical sensor and laser applications.

An apatite-mullite glass ceramics composition derived from clam shell (CS) and soda lime silicate (SLS) glass has been fabricated from a heat treatment process of composition [xCaF2·(45−x)SLS·15CS·20Al2O3·20P2O5], where x is 5, 10, 15 and 20 (wt. %). The result concluded that the Ca and Si elements were found in the CS and SLS glass respectively as a major weight composition, thereby promoting the use of waste materials in the manufacture of glass ceramic samples. Besides, the CaF2 addition lowers the glass transition temperature (Tg) and crystallisation temperature (Tc) of the glass composition. The density and percentage of the linear shrinkage of the samples differs with the addition of CaF2 and various heat treatment temperatures. For the structural properties’ analysis, the formation of fluorapatite with a needle-like microstructure and mullite phase was enhanced with a higher CaF2 content, while the growth of the anorthite phase was observed to occur at a higher heat treatment temperature. Generally, the addition of ahigh CaF2 content with the help of heat treatment in apatitemullite glass ceramics composition greatly promotes the crystallisation of the fluorapatite phase, which is crucial for denture glass ceramics.

As one of the teaching strategies that promote students with hands-on experiences linked with the community engagement, service-learning (SL) has been uniquely positioned favourable in higher education institutions. Precisely, SL is closely related to work integrated learning (WIL) in regards to blending theories with practicality. This study was primarily aimed to explore what Malaysian undergraduate students learned based on their experience in SL project. Eco-tourism industries in Malacca are represented as the community partners that also involved in the project. Twenty informants were selected among 80 students and interviewed through focus group discussions using semi-structured questions. Based on the analysis using constant comparative method, the findings revealed and discussed three emerging themes namely self-value, knowledge-sharing and managing conflicts. The application of SL components involving real situations with the community partners had stimulated broad experience in terms of students’ knowledge and values development.

This study was conducted to synthesize foam glass-ceramic using SLS glass as a precursor; eggshell (ES) as a foaming agent and investigated the effect of sintering temperature on the crystal growth, microstructure and mechanical properties of the final product. The samples undergo the sintering process at different temperatures such as 700, 800 and 900 °C for 60 min with the heating rate of 10 °C/min. The structural properties were studied by XRD, FTIR and FESEM measurement. The cristobalite (SiO2) and wollastonite (CaSiO3) phases were identified after the sintering process and their microstructure was recorded by the FESEM micrograph. The physical properties of the samples were measured by average density measurement, linear expansion and compressive strength. The lowest density measurement using the Archimedes principle was achieved by 0.421 g/cm3 with the highest volumetric expansion at 92% after the sample sintered at 800 °C. Good correlations between porosity, mechanical strength and crystal phase were observed. The invention of foam glass-ceramics from waste materials can be applied as a potential building insulation material that gives benefit to the environment and energy usage.

This study aims to fabricate low-cost foam glass-ceramic using soda-lime-silica (SLS) glass waste and clamshells (CS) as foaming agent in content between 1 and 12 wt.% by conventional powder processing method. The samples were undergoing sintering process between 700 and 1000 °C with holding time of 30 minutes and characterized according to the physical and structural properties. Samples containing 3 wt.% CS treated at 800 °C show the greatest size of porosity. As the sintering temperature increased, the samples tend to become less dense. However, for the samples sintered at 900 and 1000 °C, the trend of the density changes because of the excess CO2 gases generated during the heat treatment process promotes an increase in internal pressure, which results in the rupture of the pore walls. For linear expansion, for samples with a sintering temperature of 800 °C and higher, the increment of the temperature will lead to the decrement of linear expansion (%). As the sintering temperature increases from 700 to 800 °C, the water absorption (%) increases. However, the percentage of water absorption decreases with the further increment of sintering temperature. The XRD characterization showed the formation of wollastonite phase (CaSiO3) and further revealed the formation of greater peaks of CaSiO3 at the higher sintering temperatures. The results of compressive mechanical strength between 0.15 and 1.50 MPa indicate that the obtained glass-ceramic foams have potential for building material applications.

The need to develop future graduates that encompass employability skills has become one of the agendas in the Malaysian Educational Blueprint for Higher Education 2015- 2025. Hence, to rectify the aim, service-learning (SL) is introduced as among the strategies in promoting students with hands-on experience linked to the community engagement. Notably, the application of SL is limited despite evidences of volunteerism found in many scholarly works. SL transmits academic knowledge through volunteering works and is highly regarded as a foundation in developing students’ employability skills. Therefore, this study was conducted to explore the SL experiences and the outcomes in developing employability skills among TVET students in a Malaysian public university. Specifically, two research questions were formulated (i) what the students learned from their SL experience? and (ii) how SL project strengthen student employability skills? This study employed a qualitative case study approach to answer the research questions. The subjects of the study were purposely selected among second and third-year students in Bachelor of Education. The subjects of the study were chosen based on the criterion-based selection to ensure the rich information given by the informants. A total of four focus group discussions were conducted using semi-structured interview questions. This study utilised the Nvivo 12.0, a computerised software tool to organise and facilitate the data especially in the process of thematic analysis. The themes emerged based on students’ involvement in SL project were managing conflicts, knowledge-sharing and selfvalues. Meanwhile, four themes emerged concerning students’ employability skills development that are leadership skills, communication skills, critical thinking skills and teamwork skills. Based on the findings, SL able to be one of the subjective teaching practices for providing meaningful learning experience to students surrounded with community, which subse

The green synthesis of silica has been extensively explored over the last few decades, as silica compounds found in commercial products can cause negative effects on human health. This calls for alternative ways to produce silica that are safer, cheaper and more environmentally friendly. Some of the agricultural wastes proven to contain silica include rice husk, sugarcane bagasse, coconut shells and coconut husk. This paper describes the synthesis of silica from coconut husk waste, and its physical and optical properties for potential utilization in optical applications. Coconut husk was subjected to fire at 500–700 °C so as to form coconut husk ash (CHA), and was then treated with sulfuric acid to extract silica from the ash. Most of the weight degradation subsequently occurred at temperatures from 221 to 360 °C. X-ray fluorescence (XRF) analysis proved that 91.76% of the silica was obtained, while major peaks on the X-ray diffraction (XRD) spectrum were observed after the acid treatment. Chemical bonds such as Si-O-Si, CH2, -OH and Si-OH were found in the spectrum of the Fourier transform infrared spectroscopy (FTIR). Furthermore, the particles displayed rod-like shapes and irregular sizes, but the particle with sizes ranging from 200–750 nm decreased after the acid treatment. The relationship between the absorption coefficient and photon energy was obtained by finding the optical energy gap, which was found to be 4.3 eV. These data points provide critical information when used in optical applications. The overall studies show that synthesized silica has great potential for use in optical field applications.

In this work, waste coconut husk ash was used to prepare a ZnO-SiO2 composite. Solid-state technique was used to fabricate the composite due to its producibility, simple procedure as well as lower production cost. At high sintering temperatures ranging from 600 °C to 1000 °C, the X-ray diffraction (XRD) peaks of the Zn2SiO4 showed high intensity, which indicated high crystallinity. Furthermore, the formation of broad bands of ZnO4, Si-O-Si, and SiO4 were detected by Fourier transform infrared (FTIR) spectroscopy and the bands became narrower with the increment of sintering temperature. Besides, the morphological image from field emission scanning electron microscopy (FESEM) showed the formation of densely packed grains and smooth surface composite with the increase of sintering temperature. Upon obtaining the absorbance spectrum from Ultraviolet–Visible (UV–Vis) spectroscopy, the optical band gap was calculated to be 4.05 eV at 1000 °C. The correlation between the structural and optical properties of ZnO-SiO2 composite was discussed in detail.