UniMAP RIS :: Browsing Journal Articles by Title

Publication

A Review of Genetic Algorithm: Operations and Applications

( 2024)

;

This article presents a review of the Genetic Algorithm (GA), a prominent optimization technique inspired by natural selection and genetics. In the context of rapidly evolving computational methodologies, GA have gained considerable attention for their efficacy in solving complex optimization problems across various domains. The background highlights the growing significance of optimization techniques in addressing real-world challenges. However, the inherent complexity and diversity of problems necessitate versatile approaches like GA. The problem statement underscores the need to explore the underlying operations and applications of GA to provide a nuanced understanding of their capabilities and limitations. The objectives of this review encompass delving into the fundamental genetic operators, such as selection, crossover, and mutation, while examining their role in maintaining diversity and converging toward optimal solutions. Methodology-wise, a systematic analysis of existing literature is undertaken to distil key insights and trends in GA applications. The main findings show the adaptability of GA in tackling problems spanning engineering, economics, bioinformatics, and beyond. By facilitating the discovery of optimal or near-optimal solutions within large solution spaces, GA proves its mettle in scenarios where traditional methods fall short. The conclusion underscores the enduring relevance of GA in the optimization landscape, emphasizing their potential to remain a pivotal tool for addressing intricate real-world challenges, provided their parameters are fine-tuned judiciously to balance exploration and exploitation.

Publication

A short review on the influence of antimony addition to the microstructure and thermal properties of Lead-Free solder alloy

( 2023)

Nur Syahirah Mohamad Zaimi

;

Mohd Arif Anuar Mohd Salleh

;

Mohd. Mustafa Al Bakri Abdullah

;

Mohd Izrul Izwan Ramli

for long time, Sn-Pb solder alloys have been used extensively as the main interconnection materials in the soldering. it is no doubt that Sn-Pb offers many advantages including good electrical conductivity, mechanical properties as well as low melting temperature. however, Pb is very toxic and Pb usage poses risk to human health and environments. owing to this, the usage of Pb in the electronic industry was banned and restricted by the legislation. these factors accelerate the efforts in finding suitable replacement for solder alloy and thus lead-free solder was introduced. the major problems associated with lead-free solder is the formation of large and brittle intermetallic compound which have given a rise to the reliability issues. Micro alloying with Sb seems to be advantageous in improving the properties of existing lead-free solder alloy. thus, this paper reviews the influence of Sb addition to the lead-free solder alloy in terms of microstructure formations and thermal properties.

6 24

Publication

A State-of-the-Art Review on innovative geopolymer composites designed for water and wastewater treatment

( 2021)

Ismail Luhar

;

Salmabanu Luhar

;

Mohd. Mustafa Al Bakri Abdullah

;

Petrica Vizureanu

;

Rafiza Abd Razak

;

Andrei Victor Sandu

;

Petre-Daniel Matasaru

There is nothing more fundamental than clean potable water for living beings next to air. On the other hand, wastewater management is cropping up as a challenging task day-by-day due to lots of new additions of novel pollutants as well as the development of infrastructures and regulations that could not maintain its pace with the burgeoning escalation of populace and urbanizations. Therefore, momentous approaches must be sought-after to reclaim fresh water from wastewaters in order to address this great societal challenge. One of the routes is to clean wastewater through treatment processes using diverse adsorbents. However, most of them are unsustainable and quite costly e.g. activated carbon adsorbents, etc. Quite recently, innovative, sustainable, durable, affordable, user and eco-benevolent Geopolymer composites have been brought into play to serve the purpose as a pretty novel subject matter since they can be manufactured by a simple process of Geopolymerization at low temperature, lower energy with mitigated carbon footprints and marvellously, exhibit outstanding properties of physical and chemical stability, ion-exchange, dielectric characteristics, etc., with a porous structure and of course lucrative too because of the incorporation of wastes with them, which is in harmony with the goal to transit from linear to circular economy, i.e., “one’s waste is the treasure for another”. For these reasons, nowadays, this ground-breaking inorganic class of amorphous alumina-silicate materials are drawing the attention of the world researchers for designing them as adsorbents for water and wastewater treatment where the chemical nature and structure of the materials have a great impact on their adsorption competence. The aim of the current most recent state-of-the-art and scientometric review is to comprehend and assess thoroughly the advancements in geo-synthesis, properties and applications of geopolymer composites designed for the elimination of hazardous contaminants viz., heavy metal ions, dyes, etc. The adsorption mechanisms and effects of various environmental conditions on adsorption efficiency are also taken into account for review of the importance of Geopolymers as most recent adsorbents to get rid of the death-defying and toxic pollutants from wastewater with a view to obtaining reclaimed potable and sparkling water for reuse offering to trim down the massive crisis of scarcity of water promoting sustainable water and wastewater treatment for greener environments. The appraisal is made on the performance estimation of Geopolymers for water and wastewater treatment along with the three-dimensional printed components are characterized for mechanical, physical and chemical attributes, permeability and Ammonium (NH4+) ion removal competence of Geopolymer composites as alternative adsorbents for sequestration of an assortment of contaminants during wastewater treatment.

Publication

A sustainable photocatalytic fuel cell integrated photo-electro-Fenton hybrid system using KOH activated carbon felt cathodes for enhanced Amaranth degradation and electricity generation

( 2022-07-01)

Thor Shen Hui

;

Ho Li Ngee

;

Ong Soon An

;

Che Zulzikrami Azner Abidin

;

Heah Cheng Yong

;

Ong Yong Por

;

Yap Kea Lee

Photo-electro-Fenton (PEF) process was integrated with photocatalytic fuel cell (PFC) through the connection of electrodes and the cathodes were responsible for the acceptance of electrons. In this study, potassium hydroxide (KOH) was used to activate the carbon felt (CF) to improve the oxygen reduction reaction reactivity on cathodes for effective PFC integrated PEF hybrid system (PFC-PEF system) in Amaranth removal and electricity generation simultaneously. The results revealed that KOH activated CF cathodes had improved the electro-generation of hydrogen peroxide in both PFC and PEF and contributed to decolourisation efficiencies of 99.25% (PFC) and 96.10% (PEF). The maximum power density (4.218 μW cm−2) achieved by KOH activated CF cathode was 22% higher than that of pristine CF. The results revealed that air flow rate of 1000 mL min−1 favoured the generation of more reactive species for effective Amaranth degradation under the dissolved oxygen enrichment condition. The highest decolourisation rates were respectively achieved in PFC (0.5965 h−1) and PEF (0.2919 L mg−1 h−1) at air flow rate of 1000 mL min−1.

1

Publication

Adsorption of basic green 4 onto gasified Glyricidia sepium woodchip based activated carbon: optimization, characterization, batch and column study

(Scientific Scholar, 2020)

Anis Atikah Ahmad

;

Azam Taufik Mohd Din

;

Nasehir Khan EM Yahaya

;

Azduwin Khasri

;

Mohd Azmier Ahmad

The abundance of gasification char residues which contributed to solid waste management problem is one of the major concerns in biomass gasification industry. This study focuses on synthesizing gasified Glyricidia sepium woodchip based activated carbon (GGSWAC) for the removal of basic green 4 (BG4) dye, evaluating the GGSWAC physicochemical properties and assessing the BG4 adsorption performance in batch and fixed-bed column systems. The optimal conditions of GGSWAC synthesis were at radiation power, time, and impregnation ratio (IR) of 616 W, 1 min and 1.93 g/g, respectively. The surface area (SBET) and total pore volume (TPV) of GGSWAC were 633.30 m2/g and 0.34 cm3/g, respectively. The Fritz–Schlünder best fitted to the experimental data at all temperatures in the isothermal studies, indicating a monolayer adsorption. The kinetic study showed that BG4 adsorption followed Avrami kinetic model. Based on thermodynamic parameters, the adsorption of BG4 dye onto GGSWAC was an endothermic and spontaneous process. In continuous operation, the Thomas and Yoon–Nelson models successfully predicted BG4 adsorption onto GGSWAC. The low production cost of 0.54 USD/kg showed that GGSWAC is economically feasible for commercialization.

Publication

Advancement in recycling waste tire activated carbon to potential adsorbents

( 2022-12-01)

Umi Fazara Md Ali

;

Hussin F.

;

Subash Chandra Bose Gopinath

;

Aroua M.K.

;

Khamidun M.H.

;

Jusoh N.

;

Naimah Ibrahim

;

Syahirah Faraheen Kabir Ahmad

Waste tires have been identified as one of the contributors to environmental problems and the issue of inadequate landfill spaces. The lack of consistent and systematic approaches such as specific regulations/laws or mechanisms of waste management to waste tires, limited application of technology for recycling waste tires and lack of awareness on the impacts of waste tires problem, make waste tires a source of environmental pollution. Various researches have been conducted on recycling waste tires into polymer bends, and materials to harden concretes, fuels and adsorbent. Researchers suggested that pyrolysis is the current trend of recycling waste tire to harvest the saleable pyrolysis oil and the recycled carbon black. Therefore, this review attempts to compile relevant knowledge about the potential of adsorbent derived from waste tires to be applied in the removal of various types of pollutants like heavy metals, organic pollutants, dye and air/gaseous pollutant. Studies were carried out on revealing the properties and the characteristics of activated carbon derived from waste tire as effective adsorbent which influence the application performance at liquid or gas phase. In addition, the challenges in the production of activated carbon derived from waste tire were discussed.

1

Publication

Alkaline-Activation technique to produce low-temperature sintering activated-HAp ceramic

( 2023)

Wan Mohd Arif W Ibrahim

;

Mohd. Mustafa Al Bakri Abdullah

;

Noorina Hidayu Jamil

;

Hasmaliza Mohamad

;

Mohd Arif Anuar Mohd Salleh

;

Andrei Victor Sandu

;

Petrica Vizureanu

;

Madalina Simona Baltatu

;

Patimapon Sukmak

The fabrication of hydroxyapatite (HAp) ceramics prepared by existing conventional sintering requires high-temperature sintering of 1250 °C to 1300 °C. In this paper, the activated metakaolin (MK)/HAp specimens were prepared from varied mix design inputs, which were varied solid mixtures (different amounts of MK loading in HAp) and liquid-to-solid (L/S) ratios, before being pressed and sintered at 900 °C. Phase analysis, thermal analysis, surface morphology, and tensile strength of the specimens were investigated to study the influences of the Al, Si, Fe, Na, and K composition on the formation of the hydroxyapatite phase and its tensile strength. XRD analysis results show the formation of different phases was obtained from the different mix design inputs HAp (hexagonal and monoclinic), calcium phosphate, sodium calcium phosphate silicate and calcium hydrogen phosphate hydrate. Interestingly, the specimen with the addition of 30 g MK prepared at a 1.25 L/S ratio showed the formation of a monoclinic hydroxyapatite phase, resulting in the highest diametrical tensile strength of 12.52 MPa. Moreover, the increment in the MK amount in the specimens promotes better densification when sintered at 900 °C, which was highlighted in the microstructure study. This may be attributed to the Fe2O3, Na2O, and K2O contents in the MK and alkaline activator, which acted as a self-fluxing agent and contributed to the lower sintering temperature. Therefore, the research revealed that the addition of MK in the activated-HAp system could achieve a stable hydroxyapatite phase and better tensile strength at a low sintering temperature.

3 10

Publication

Analisis Sosiolinguistik masyarakat Melayu di tiga wilayah sempadan Selatan Thailand berlandaskan teori etnografi komunikasi

( 2019-12)

Kamaruddin Isayah

Kertas kerja ini bertujuan untuk memaparkan situasi sosiolinguistik dan fenomena kebahasaan dalam masyarakat Melayu di tiga wilayah sempadan selatan Thailand (3WSST). Data sosiolinguistik yang terkumpul melalui kajian pustaka, pemerhatian dan temu bual tidak terancang dianalisis secara deskriptif menggunakan teori etnografi komunikasi yang dicadangkan oleh Hymes (1974) melalui singkatan komponen tutur tertentu, iaitu SPEAKING. Masyarakat Melayu di 3WSST yang dimaksudkan dalam kertas kerja ini merangkumi wilayah Pattani, Yala dan Narathiwat. Memandangkan pengkelompokan etnik di Thailand, masyarakat Melayu merupakan sebuah masyarakat minoriti di negara ini. Di bahagian hujung Selatan Thailand, masyarakat ini dianggap majoriti penduduknya. Identiti yang melambangkan masyarakat ini bersifat Melayu ialah pembentukan masyarakat sejak zaman silam hingga sekarang berunsurkan ciri-ciri Melayu, iaitu dengan mengamalkan adat dan budaya Melayu. Sejarah telah membuktikan bahawa masyarakat di sini ialah masyarakat Melayu asal yang tidak diasimilasikan daripada mana-mana masyarakat. Bahasa Melayu khususnya dialek Melayu Patani merupakan medium utama bagi penduduk masyarakat ini. Dari sudut sosiolinguistik, masyarakat Melayu di 3WSST jelas sekali mengalami fenomena pertembungan dengan orang Thai, kesannya muncul sebuah masyarakat dwibahasa. Hakikatnya, fenomena kedwibahasaan dalam masyarakat ini mengakibatkan berlakunya beberapa aspek linguistik seperti fenomena pemilihan bahasa, percampuran bahasa dan sebagainya.

14 6

Publication

Analysis of human epidermal growth factor receptor 2 interaction on aptamer‐probed interdigitated electrode for breast cancer diagnosis

( 2024)

Yingxin Hao

;

Subash Chandra Bose Gopinath

AbstractBreast cancer has been reported to be high in its incidence with women, and early identification of breast cancer helps to improve and provide an effective treatment. Tumor markers are active substances; in particular, human epidermal growth factor receptor 2 (HER2) is over‐expressed at the level of 20%–30%. This research work developed a highly sensitive HER2 biosensor on the interdigitated electrode (IDE) by using aptamer as a detection probe. To enhance the analytical performances, aptamer was attached to the gold nanoparticle and immobilized on the IDE through a chemical linker [(3‐aminopropyl)triethoxysilane]. On the aptamer conjugation, HER2 was quantified through current‐volt measurements, and the limit of detection of HER2 was calculated as 1 pg/mL on a linear range from 0.1 to 3000 pg/mL at anR2(regression coefficient) of 0.9657. Further, a selective performance with human serum increased the current responses by increasing HER2 concentrations. Specific experiments with control protein and complementary aptamer sequence failed to enhance the current responses. This HER2 biosensor reflects the occurrence of breast cancer at its lower abundance and helps to identify the associated complications.

Publication

Artificial lightweight aggregates made from pozzolanic material: A review on the method, physical and mechanical properties, thermal and microstructure

( 2022)

Dickson Ling Chuan Hao

;

Rafiza Abd Razak

;

Marwan Kheimi

;

Zarina Yahya

;

Mohd. Mustafa Al Bakri Abdullah

;

Dumitru Doru Burduhos Nergis

;

Hamzah Fansuri

;

Ratna Ediati

;

Rosnita Mohamed

;

Alida Abdullah

As the demand for nonrenewable natural resources, such as aggregate, is increasing worldwide, new production of artificial aggregate should be developed. Artificial lightweight aggregate can bring advantages to the construction field due to its lower density, thus reducing the dead load applied to the structural elements. In addition, application of artificial lightweight aggregate in lightweight concrete will produce lower thermal conductivity. However, the production of artificial lightweight aggregate is still limited. Production of artificial lightweight aggregate incorporating waste materials or pozzolanic materials is advantageous and beneficial in terms of being environmentally friendly, as well as lowering carbon dioxide emissions. Moreover, additives, such as geopolymer, have been introduced as one of the alternative construction materials that have been proven to have excellent properties. Thus, this paper will review the production of artificial lightweight aggregate through various methods, including sintering, cold bonding, and autoclaving. The significant properties of artificial lightweight aggregate, including physical and mechanical properties, such as water absorption, crushing strength, and impact value, are reviewed. The properties of concrete, including thermal properties, that utilized artificial lightweight aggregate were also briefly reviewed to highlight the advantages of artificial lightweight aggregate.

Publication

ASPAD dynamic simulation and artificial neural network for atenolol adsorption in GGSWAC packed bed column

( 2023)

Kah Zheng Goh

;

Anis Atikah Ahmad

;

Mohd Azmier Ahmad

Publication

Assessment of geopolymer concrete for underwater concreting properties

( 2021)

Fakhryna Hannanee Ahmad Zaidi

;

Romisuhani Ahmad

;

Mohd. Mustafa Al Bakri Abdullah

;

Wan Mastura Wan Ibrahim

;

Ikmal Hakem Aziz

;

Subaer Junaidi

;

Salmabanu Luhar

For ages, concrete has been used to construct underwater structures. Concrete laying underwater is a very complex procedure important to the success or failure of underwater projects. This paper elucidates the influence of alkali activator ratios on geopolymers for underwater concreting; focusing on the geopolymer concrete synthesized from fly ash and kaolin activated using sodium hydroxide and sodium silicate solutions. The geopolymer mixtures were designed to incorporate multiple alkali activator ratios to evaluate their effects on the resulting geopolymers’ properties. The fresh concrete was molded into 50 mm cubes in seawater using the tremie method and tested for its engineering properties at 7 and 28 days (curing). The control geopolymer and underwater geopolymers’ mechanical properties, such as compressive strength, water absorption density, and setting time were also determined. The differences between the control geopolymer and underwater geopolymer were determined using phase analysis and functional group analysis. The results show that the geopolymer samples were optimally strengthened at a 2.5 alkali activator ratio, and the mechanical properties of the control geopolymer exceeded that of the underwater geopolymer. However, the underwater geopolymer was determined to be suitable for use as underwater concreting material as it retains 70% strength of the control geopolymer.

Publication

Biological synthesis of zinc-oxide nanoparticle using wide-spread Lentinus sajor-caju extract as a carrier for natural-compounds

(Elsevier, 2023)

Malinie Rajasingam

;

Subash Chandra Bose Gopinath

;

Periasamy Anbu

;

Sekar Vijayakumar

The use of nanotechnology in industry and medicine has recently become a hot topic of research. This study focused on synthesizing zinc oxide nanoparticles (ZnONPs) using Lentinus sajor-caju extract, followed by applying the nanoparticle as a carrier for natural compounds. Energy dispersive X-ray spectroscopy (EDX), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Field-emission scanning electron microscopy (FESEM), Filed-emission transmission electron microscopy (FETEM), and zeta potential measurements were used to characterize the synthesized nanoparticles. The synthesis of ZnONPs was also confirmed by UV–visible spectroscopy. The ZnONPs had a spherical shape with an average size of 28 nm in diameter, according to FETEM and FESEM. X-ray powder diffraction and selected area electron diffraction showed that the ZnONPs were crystalline in structure. The active components of the L. sajor-caju extracts were found to cap the ZnONPs, according to FTIR analysis. Additionally, EDX analysis revealed test showed the elemental composition of ZnONP's. The performance of the L. sajor-caju-capped ZnONP conjugated with a drug was studied in terms of inhibition of microbial growth against gram-negative and gram-positive bacteria through the disc diffusion method. The results demonstrated a considerable inhibition of both bacteria, demonstrating ZnONP's potential for use in biomedicine.

Publication

Biotechnological processes in microbial Amylase production

( 2017)

Subash C. B. Gopinath

;

Periasamy Anbu

;

Mohd Khairuddin Md Arshad

;

Thangavel Lakshmipriya

;

Voon Chun Hong

;

Uda Hashim

;

Suresh V. Chinni

Amylase is an important and indispensable enzyme that plays a pivotal role in the field of biotechnology. It is produced mainly from microbial sources and is used in many industries. Industrial sectors with top-down and bottom-up approaches are currently focusing on improving microbial amylase production levels by implementing bioengineering technologies. The further support of energy consumption studies, such as those on thermodynamics, pinch technology, and environment-friendly technologies, has hastened the large-scale production of the enzyme. Herein, the importance of microbial (bacteria and fungi) amylase is discussed along with its production methods from the laboratory to industrial scales.

4 11

Publication

Challenges and impacts of COVID-19 pandemic on global waste management systems: a review

( 2022)

Ismail Luhar

;

Salmabanu Luhar

;

Mohd. Mustafa Al Bakri Abdullah

Unfortunately, nearly the whole world came to a standstill due to the coronavirus disease 2019, i.e., the COVID-19 pandemic, which negatively and severely impacted almost all facets of society, systems, and lives on the planet during the last few years. During this time, a surge in the generation of a huge volume of diverse wastes at an unprecedented rate occurred due to the extensive use of disposables and personal shielding safety gear such as personal protective equipment (PPE) for both infected and uninfected people as well as frontline staff, etc., as corona protocols, especially in the form of “plastic wastes”. Consequently, all these factors induced a novel route for the pollution of air, soil, and water, inviting a great number of health hazards in addition to the pandemic. Beyond a doubt, the susceptibility of the spread of the coronavirus through polluted waste is high, an issue for which the waste management measures are comparatively not up to the mark. The spread of COVID-19 forced the world into lockdown, which had both constructive and unconstructive effects on not only the environment but also systems such as the waste management sector, etc. The unforeseen increase in the quantity of waste created a challenge concerning normal waste disposal facilities, negatively impacting the global waste management industry, and hence, leading to an urgent situation internationally. Still, in developing nations, the sector of waste management is at its nascent stage, and therefore, the sector of waste management during the pandemic period has been influenced severely in many parts of the world. The current comprehensive review provides not only an overview of the impacts and challenges of COVID-19 on the waste management sector but also extends the systematic data of waste generation that has been made accessible so far along with a discussion on the safety of the related workers and staff as well as suggestions for the possible approaches towards better waste management services, which are essential to manage the waste increase resultant of the COVID-19 pandemic in a majority of nations.

3 3

Publication

Characterization of SnO₂/TiO₂ with the addition of Polyethylene Glycol via sol-gel method for self-cleaning application

( 2022)

Dewi Suriyani Che Halin

;

A. Azliza

;

Kamrosni Abdul Razak

;

V. Chobpattana

;

Mohd Arif Anuar Mohd Salleh

;

Juyana A. Wahab

;

Mohd Mustafa Albakri Abdullah

;

L. Kaczmarek

;

M. Nabiałek

;

B. Jeż

TiO₂ is one of the most widely used metal oxide semiconductors in the field of photocatalysis for the self-cleaning purpose to withdraw pollutants. Polyethylene glycol (PEG) is recommended as a stabilizer and booster during preparation of water-soluble TiO₂. Preparation of SnO₂/TiO₂ thin film deposition on the surface of ceramic tile was carried out by the sol-gel spin coating method by adding different amount of PEG (0g, 0.2g, 0.4g, 0.6g, 0.8g) during the preparation of the sol precursor. The effects of PEG content and the annealing temperature on the phase composition, crystallite size and the hydrophilic properties of SnO₂/TiO₂ films were studied. The X-ray diffraction (XRD) spectra revealed different phases existed when the films were annealed at different annealing temperatures of 350°C, 550°C and 750°C with 0.4 g of PEG addition. The crystallite sizes of the films were measured using Scherrer equation. It shows crystallite size was dependent on crystal structure existed in the films. The films with mixed phases of brookite and rutile shows the smallest crystallite size. In order to measure the hydrophilicity properties of films, the water contact angles for each film with different content of PEG were measured. It can be observed that the water contact angle decreased with the increasing of the content of PEG. It shows the superhydrophilicity properties for the films with the 0.8 g of PEG annealed at 750°C. This demonstrates that the annealed temperature and the addition of PEG affect the phase composition and the hydrophilicity properties of the films

3 20

Publication

Chemical distributions of different Sodium Hydroxide molarities on fly ash/dolomite-based geopolymer

( 2022)

Wan Mastura Wan Ibrahim

;

Mohd. Mustafa Al Bakri Abdullah

;

Romisuhani Ahmad

;

Andrei Victor Sandu

;

Petrica Vizureanu

;

Omrane Benjeddou

;

Afikah Rahim

;

Masdiyana Ibrahim

;

Ahmad Syauqi Sauffi

Geopolymers are an inorganic material in an alkaline environment that is synthesized with alumina–silica gel. The structure of geopolymers consists of an inorganic chain of material and a covalent-bound molecular system. Currently, Ordinary Portland Cement (OPC) has caused carbon dioxide (CO2) emissions which causes greenhouse effects. This analysis investigates the impact on fly ash/dolomite-based-geopolymer with various molarities of sodium hydroxide solutions which are 6 M, 8 M, 10 M, 12 M and 14 M. The samples of fly ash/dolomite-based-geopolymer were prepared with the usage of solid to liquid of 2.0, by mass and alkaline activator ratio of 2.5, by mass. After that, the geopolymer was cast in 50 × 50 × 50 mm molds before testing after 7 days of curing. The samples were tested on compressive strength, density, water absorption, morphology, elemental distributions and phase analysis. From the results, the usage of 8 M of NaOH gave the optimum properties for the fly ash/dolomite-based geopolymer. The elemental distribution analysis exposes the Al, Si, Ca, Fe and Mg chemical distribution of the samples from the selected area. The distribution of the elements is related to the compressive strength and compared with the chemical composition of the fly ash and dolomite.

1 4

Publication

Chemical-free saturated steam pretreatment of oil palm empty fruit bunch for improved enzymatic saccharification

( 2024)

Saleha Shamsudin

;

Ezyana Kamal Bahrin

;

Mohd Ali Hassan

;

Yoshihito Shirai

Publication

Cold-pressed fly ash geopolymers: effect of formulation on mechanical and morphological characteristics

( 2021)

Ong Shee-Ween

;

Heah Cheng Yong

;

Lynette Wei Ling Chan

;

Mohd. Mustafa Al Bakri Abdullah

;

Ho Li Ngee

;

Liew Yun Ming

;

Ooi Wan-En

;

Ng Yong-Sing

;

Nur Ain Jaya

This research uses low alkali activator content and cold pressing technique for fly ash-based geopolymers formation under room temperature condition. The geopolymers were prepared using four different parameters: fly ash/alkali activator ratio, sodium hydroxide concentration, sodium silicate/sodium hydroxide ratio and pressing force. The results indicated that the compressive strength (114.2 MPa) and flexural strength (29.9 MPa) of geopolymers maximised at a fly ash/alkali activator ratio of 5.5, a 14 M sodium hydroxide concentration, a sodium silicate/sodium hydroxide ratio of 1.5 and a pressing force of 5 tons (pressing stress of 100.0 MPa and 155.7 MPa for compressive and flexural samples, respectively). The degree of reaction (40.1%) enhanced the structure compactness with minimum porosity. The improved mechanical properties confirmed that a high strength pressed geopolymer could be formed at low alkali activator content without the aid of temperature.

9 21

Publication

Colloidal stability of polyelectrolyte-functionalized magnetic nanoparticles: experimental and theoretical studies

( 2024)

Kai Ping Low

;

Wei Ming Ng

;

Sim Siong Leong

;

Pey Yi Toh

;

JitKang Lim

;

Ng Qi Hwa

;

Chong Hooi Lim

;

Yi Peng Teoh

Journal Articles

Permanent URI for this collection

Browse

Browse

Browsing Journal Articles by Title

Results Per Page

Sort Options