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Fulltext The dataset for validation of factors affecting pre-service teachers' use of ICT during teaching practices: Indonesian context

Habibi A, Yusop FD, Razak RA

Data Brief, 2020 Feb;28:104875.
PMID: 31853470 DOI: 10.1016/j.dib.2019.104875

This dataset describes two main variables, technological pedagogical and content knowledge (TPACK) and Beliefs on ICT, which may affect pre-service teachers' (PSTs) use of ICT (UICT) during teaching practices. TPACK assumes that PSTs should actively combine some domains of knowledge to design good quality of ICT-integrated courses lessons. Beliefs on ICT in this study consist of a mix of behavioral, normative, and control beliefs on ICT integration in education. In addition, UICT is defined as ICT used by PSTs during teaching practices. Three approaches were applied for the purification of the dataset; development of instruments, survey, and exploratory factor analysis (EFA). The dataset consists of demographic information, TPACK, Beliefs on ICT, and UICT. The dataset is beneficial to teacher educators in designing effective programs that best nurture PSTs' UICT during teaching practices. Researchers sharing similar sample characteristics in developing countries may adapt this dataset for more rigorous statistical analyses.
Fulltext The comprehension and production of Wh- questions among Malay children with developmental language disorders: Climbing the syntactic tree

Abu Bakar N, Smith G, Razak RA, Garraffa M

Front Psychol, 2022;13:948992.
PMID: 36389519 DOI: 10.3389/fpsyg.2022.948992

This study is an investigation of both comprehension and production of Wh- questions in Malay-speaking children with a developmental language disorder (DLD). A total of 15 Malay children with DLD (ages 7;0-9;11 years) were tested on a set of Wh- questions (who subject and object, which subject and object), comparing their performance with two control groups [15 age-matched typically developing (TD) children and 15 younger TD language-matched children]. Malay children with DLD showed a clear asymmetry in comprehension of Wh- questions, with a selective impairment for which NP questions compared with who questions. Age-matched controls performed at ceiling in all Wh- questions, while the language-matched group reported a subject/object asymmetry selective for the which NP, as reported in other languages. In production, both children with DLD and younger children showed a preference for questions with in situ Wh- elements, a structure that is allowed in colloquial Malay, but which is not produced by the age-matched TD group. Several non-adult-like strategies were adopted particularly by the children with DLD to avoid complex sentences, including substitution with yes/no echo questions, production of the wrong Wh- question, and use of a generic Wh- element. The study provides an insight on the mastery of Wh- questions in both typical Malay children and children with DLD. Implications for the definition of a clinical marker for DLD in a free word order language with Wh- in situ option will be discussed.
Fulltext Fly ash-based geopolymer lightweight concrete using foaming agent

Al Bakri Abdullah MM, Hussin K, Bnhussain M, Ismail KN, Yahya Z, Razak RA

Int J Mol Sci, 2012;13(6):7186-98.
PMID: 22837687 DOI: 10.3390/ijms13067186

In this paper, we report the results of our investigation on the possibility of producing foam concrete by using a geopolymer system. Class C fly ash was mixed with an alkaline activator solution (a mixture of sodium silicate and NaOH), and foam was added to the geopolymeric mixture to produce lightweight concrete. The NaOH solution was prepared by dilute NaOH pellets with distilled water. The reactives were mixed to produce a homogeneous mixture, which was placed into a 50 mm mold and cured at two different curing temperatures (60 °C and room temperature), for 24 hours. After the curing process, the strengths of the samples were tested on days 1, 7, and 28. The water absorption, porosity, chemical composition, microstructure, XRD and FTIR analyses were studied. The results showed that the sample which was cured at 60 °C (LW2) produced the maximum compressive strength for all tests, (11.03 MPa, 17.59 MPa, and 18.19 MPa) for days 1, 7, and 28, respectively. Also, the water absorption and porosity of LW2 were reduced by 6.78% and 1.22% after 28 days, respectively. The SEM showed that the LW2 sample had a denser matrix than LW1. This was because LW2 was heat cured, which caused the geopolymerization rate to increase, producing a denser matrix. However for LW1, microcracks were present on the surface, which reduced the compressive strength and increased water absorption and porosity.
Fulltext Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer

Razak RA, Abdullah MM, Hussin K, Ismail KN, Hardjito D, Yahya Z

Int J Mol Sci, 2015;16(5):11629-47.
PMID: 26006238 DOI: 10.3390/ijms160511629

This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA) using LUSI (Sidoarjo mud) and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA) ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value) of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA) ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM) image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced.
Other factors to consider in the formation of chloropropandiol fatty esters in oil processes

Ramli MR, Siew WL, Ibrahim NA, Kuntom A, Abd Razak RA

Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2015;32(6):817-24.
PMID: 25798697 DOI: 10.1080/19440049.2015.1032368

This paper examines the processing steps of extracting palm oil from fresh fruit bunches in a way that may impact on the formation of chloropropandiol fatty esters (3-MCPD esters), particularly during refining. Diacylglycerols (DAGs) do not appear to be a critical factor when crude palm oils are extracted from various qualities of fruit bunches. Highly hydrolysed oils, in spite of the high free fatty acid (FFA) contents, did not show exceptionally high DAGs, and the oils did not display a higher formation of 3-MCPD esters upon heat treatment. However, acidity measured in terms of pH appears to have a strong impact on 3-MCPD ester formation in the crude oil when heated at high temperatures. The differences in the extraction process of crude palm oil from current commercial processes and that from a modified experimental process showed clearly the effect of acidity of the oil on the formation of 3-MCPD esters. This paper concludes that the washing or dilution step in palm oil mills removes the acidity of the vegetative materials and that a well-optimised dilution/washing step in the extraction process will play an important role in reducing formation of 3-MCPD esters in crude palm oil upon further heat processing.
Verification and evaluation of monochloropropanediol (MCPD) esters and glycidyl esters in palm oil products of different regions in Malaysia

Abd Razak RA, Ahmad Tarmizi AH, Abdul Hammid AN, Kuntom A, Ismail IS, Sanny M

Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2019 Nov;36(11):1626-1636.
PMID: 31437078 DOI: 10.1080/19440049.2019.1654139

This study was conducted to investigate on the effect of different sampling regions of palm-refined oils and fats on the 2- and 3-monochloropropanediol fatty acid esters (MCPDE) and glycidol fatty acid esters (GE) levels. The American Oil Chemists' Society (AOCS) Official Method Cd 29a-13 on the determination of MCPDE and GE in edible oils and fats by acid transesterification was successfully verified and optimised, with slight modification using 7890A Agilent GC system equipped with 5975C quadrupole detector. The determined limits of detection (LOD) for MCPDE were 0.02 mg kg-1 and 0.05 mg kg-1 for GE. The method performance has showed good recovery between 80% and 120% for all pertinent compounds with seven replicates assayed in three separate days. Round robin test with two European laboratories, i.e. Eurofins and SGS, has shown compliance results with those of the present study. Among the sampling regions, only one refinery located in the central region of Malaysia showed a significant increment of the MCPDE and GE levels after refining process. The GE level averaging at 2.5 mg kg-1 was slightly higher than that of 3-MCPDE averaging at 1.3 mg kg-1. Both esters were preferentially partitioned into the liquid phase rather than the solid phase after fractionation. However, the overall results exhibited no direct correlation between the esters content and the different sampling locations of the palm oil products in Malaysia. Analysis of total chlorine content also displayed significant variations between sampling locations which clearly show its effect on the chlorine content in the CPO samples.
Fulltext The Effects of Various Concentrations of NaOH on the Inter-Particle Gelation of a Fly Ash Geopolymer Aggregate

Abdullah A, Hussin K, Abdullah MMAB, Yahya Z, Sochacki W, Razak RA, et al.

Materials (Basel), 2021 Feb 27;14(5).
PMID: 33673522 DOI: 10.3390/ma14051111

Aggregates can be categorized into natural and artificial aggregates. Preserving natural resources is crucial to ensuring the constant supply of natural aggregates. In order to preserve these natural resources, the production of artificial aggregates is beginning to gain the attention of researchers worldwide. One of the methods involves using geopolymer technology. On this basis, this current research focuses on the inter-particle effect on the properties of fly ash geopolymer aggregates with different molarities of sodium hydroxide (NaOH). The effects of synthesis parameters (6, 8, 10, 12, and 14 M) on the mechanical and microstructural properties of the fly ash geopolymer aggregate were studied. The fly ash geopolymer aggregate was palletized manually by using a hand to form a sphere-shaped aggregate where the ratio of NaOH/Na2SiO3 used was constant at 2.5. The results indicated that the NaOH molarity has a significant effect on the impact strength of a fly ash geopolymer aggregate. The highest aggregate impact value (AIV) was obtained for samples with 6 M NaOH molarity (26.95%), indicating the lowest strength among other molarities studied and the lowest density of 2150 kg/m3. The low concentration of sodium hydroxide in the alkali activator solution resulted in the dissolution of fly ash being limited; thus, the inter-particle volume cannot be fully filled by the precipitated gels.
A Review of Machine Learning Methods of Feature Selection and Classification for Autism Spectrum Disorder

Rahman MM, Usman OL, Muniyandi RC, Sahran S, Mohamed S, Razak RA

Brain Sci, 2020 Dec 07;10(12).
PMID: 33297436 DOI: 10.3390/brainsci10120949

Autism Spectrum Disorder (ASD), according to DSM-5 in the American Psychiatric Association, is a neurodevelopmental disorder that includes deficits of social communication and social interaction with the presence of restricted and repetitive behaviors. Children with ASD have difficulties in joint attention and social reciprocity, using non-verbal and verbal behavior for communication. Due to these deficits, children with autism are often socially isolated. Researchers have emphasized the importance of early identification and early intervention to improve the level of functioning in language, communication, and well-being of children with autism. However, due to limited local assessment tools to diagnose these children, limited speech-language therapy services in rural areas, etc., these children do not get the rehabilitation they need until they get into compulsory schooling at the age of seven years old. Hence, efficient approaches towards early identification and intervention through speedy diagnostic procedures for ASD are required. In recent years, advanced technologies like machine learning have been used to analyze and investigate ASD to improve diagnostic accuracy, time, and quality without complexity. These machine learning methods include artificial neural networks, support vector machines, a priori algorithms, and decision trees, most of which have been applied to datasets connected with autism to construct predictive models. Meanwhile, the selection of features remains an essential task before developing a predictive model for ASD classification. This review mainly investigates and analyzes up-to-date studies on machine learning methods for feature selection and classification of ASD. We recommend methods to enhance machine learning's speedy execution for processing complex data for conceptualization and implementation in ASD diagnostic research. This study can significantly benefit future research in autism using a machine learning approach for feature selection, classification, and processing imbalanced data.
Fulltext Malaysian Carica papaya L. var. Eksotika: Current Research Strategies Fronting Challenges

Sekeli R, Hamid MH, Razak RA, Wee CY, Ong-Abdullah J

Front Plant Sci, 2018;9:1380.
PMID: 30279695 DOI: 10.3389/fpls.2018.01380

Carica papaya L. or commonly known as papaya, is a major tropical crop consumed worldwide either as a vegetable or fresh fruit or processed products. In Malaysia, papaya was initially planted as a smallholder crop throughout the country. Eventually after 15 years of breeding and selection, a new variety, named C. papaya L. var. Eksotika, was released by the Malaysian Agricultural Research and Development Institute (MARDI) in 1987. This event changed the outlook of papaya planting from a smallholder crop to a plantation crop. Despite the blooming papaya business, the industry faced various disease issues that jeopardize its future. The most devastating was the papaya dieback disease, which affected approximately 800 hectares of plantation, destroyed approximately 1 million trees nationwide with total losses estimated at US$ 58 million. Even though Eksotika is a favored commercial variety with good eating and aesthetic quality fruit, its potential for more lucrative distant markets is tarnished with its short-shelf life fruits. Several strategies had been reported to address the challenges faced by Eksotika specifically against the dieback disease and the fruit's short shelf-life. This review focuses on C. papaya L. var. Eksotika particularly on the strategies to address the challenges faced in order to sustain the economic value of this crop plant, which had contributed significantly to the Malaysian economy.
Vitamin A and E Homologues Impacting the Fate of Acrylamide in Equimolar Asparagine-Glucose Model System

Kuek SL, Tarmizi AHA, Abd Razak RA, Jinap S, Sanny M

Antioxidants (Basel), 2021 Jun 22;10(7).
PMID: 34206458 DOI: 10.3390/antiox10070993

This study aims to evaluate the influence of Vitamin A and E homologues toward acrylamide in equimolar asparagine-glucose model system. Vitamin A homologue as β-carotene (BC) and five Vitamin E homologues, i.e., α-tocopherol (AT), δ-tocopherol (DT), α-tocotrienol (ATT), γ-tocotrienol (GTT), and δ-tocotrienol (DTT), were tested at different concentrations (1 and 10 µmol) and subjected to heating at 160 °C for 20 min before acrylamide quantification. At lower concentrations (1 µmol; 431, 403, 411 ppm, respectively), AT, DT, and GTT significantly increase acrylamide. Except for DT, enhancing concentration to 10 µmol (5370, 4310, 4250, 3970, and 4110 ppm, respectively) caused significant acrylamide formation. From linear regression model, acrylamide concentration demonstrated significant depreciation over concentration increase in AT (Beta = -83.0, R2 = 0.652, p ≤ 0.05) and DT (Beta = -71.6, R2 = 0.930, p ≤ 0.05). This study indicates that different Vitamin A and E homologue concentrations could determine their functionality either as antioxidants or pro-oxidants.
Fulltext The Effect of Various Waste Materials' Contents on the Attenuation Level of Anti-Radiation Shielding Concrete

Azeez AB, Mohammed KS, Abdullah MMAB, Hussin K, Sandu AV, Razak RA

Materials (Basel), 2013 Oct 23;6(10):4836-4846.
PMID: 28788363 DOI: 10.3390/ma6104836

Samples of concrete contain various waste materials, such as iron particulates, steel balls of used ball bearings and slags from steel industry were assessed for their anti-radiation attenuation coefficient properties. The attenuation measurements were performed using gamma spectrometer of NaI (Tl) detector. The utilized radiation sources comprised (137)Cs and ⁶⁰Co radioactive elements with photon energies of 0.662 MeV for (137)Cs and two energy levels of 1.17 and 1.33 MeV for the ⁶⁰Co. Likewise the mean free paths for the tested samples were obtained. The aim of this work is to investigate the effect of the waste loading rates and the particulate dispersive manner within the concrete matrix on the attenuation coefficients. The maximum linear attenuation coefficient (μ) was attained for concrete incorporates iron filling wastes of 30 wt %. They were of 1.12 ± 1.31×10(-3) for (137)Cs and 0.92 ± 1.57 × 10(-3) for ⁶⁰Co. Substantial improvement in attenuation performance by 20%-25% was achieved for concrete samples incorporate iron fillings as opposed to that of steel ball samples at different (5%-30%) loading rates. The steel balls and the steel slags gave much inferior values. The microstructure, concrete-metal composite density, the homogeneity and particulate dispersion were examined and evaluated using different metallographic, microscopic and measurement facilities.
Fulltext A State-of-the-Art Review on Innovative Geopolymer Composites Designed for Water and Wastewater Treatment

Luhar I, Luhar S, Abdullah MMAB, Razak RA, Vizureanu P, Sandu AV, et al.

Materials (Basel), 2021 Dec 04;14(23).
PMID: 34885611 DOI: 10.3390/ma14237456

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.
Hypothalamic germinoma masquerading as superior mesenteric artery (SMA) syndrome

Vethakkan SR, Venugopal Y, Tan AT, Paramasivam SS, Ratnasingam J, Razak RA, et al.

Endocr Pract, 2012 11 29;19(1):e29-34.
PMID: 23186972 DOI: 10.4158/EP12218.CR

OBJECTIVE: To report a case of superior mesenteric artery (SMA) syndrome secondary to hypothalamic germinoma.
METHODS: We describe the clinical presentation, diagnostic work-up, management, and clinical course of a patient admitted with SMA syndrome who was subsequently found to have a hypothalamic germinoma.
RESULTS: An adolescent boy was admitted to the surgical ward with progressive weight loss over a 2 year period and postprandial vomiting. He was diagnosed with SMA syndrome based on evidence of proximal duodenal dilatation, extrinsic compression of the distal duodenum, and a narrowed aortomesenteric angle (16°). Investigations performed to exclude thyrotoxicosis unexpectedly revealed secondary hypothyroidism and further evaluation demonstrated evidence of pan-hypopituitarism. Psychiatric evaluation excluded anorexia nervosa and bulimia. Magnetic resonance imaging (MRI) of the brain revealed a heterogeneously enhancing hypothalamic lesion, but a normal pituitary gland. Hormone replacement with hydrocortisone, desmopressin, testosterone, and thyroxine resulted in weight gain and resolution of gastrointestinal symptoms. A transventricular endoscopic biopsy subsequently confirmed a hypothalamic germinoma and he was referred to an oncologist.
CONCLUSION: SMA syndrome secondary to severe weight loss is an uncommon cause of upper gastrointestinal obstruction. While there have been reports of poorly controlled diabetes mellitus and thyrotoxicosis manifesting as SMA syndrome, there are no published reports to date of SMA syndrome secondary to hypothalamic/pituitary disease. Management of SMA syndrome is conservative, as symptoms of intestinal obstruction resolve with weight gain following treatment of the underlying cause. Awareness of this uncommon presentation of endocrine cachexia/hypothalamic disease will prevent unnecessary laparotomies and a misdiagnosis of an eating disorder.
Fulltext Behavior of Alkali-Activated Fly Ash through Underwater Placement

Yahya Z, Abdullah MMAB, Li LY, Burduhos Nergis DD, Hakimi MAAZ, Sandu AV, et al.

Materials (Basel), 2021 Nov 14;14(22).
PMID: 34832267 DOI: 10.3390/ma14226865

Underwater concrete is a cohesive self-consolidated concrete used for concreting underwater structures such as bridge piers. Conventional concrete used anti-washout admixture (AWA) to form a high-viscosity underwater concrete to minimise the dispersion of concrete material into the surrounding water. The reduction of quality for conventional concrete is mainly due to the washing out of cement and fine particles upon casting in the water. This research focused on the detailed investigations into the setting time, washout effect, compressive strength, and chemical composition analysis of alkali-activated fly ash (AAFA) paste through underwater placement in seawater and freshwater. Class C fly ash as source materials, sodium silicate, and sodium hydroxide solution as alkaline activator were used for this study. Specimens produced through underwater placement in seawater showed impressive performance with strength 71.10 MPa on 28 days. According to the Standard of the Japan Society of Civil Engineers (JSCE), the strength of specimens for underwater placement must not be lower than 80% of the specimen's strength prepared in dry conditions. As result, the AAFA specimens only showed 12.11% reduction in strength compared to the specimen prepared in dry conditions, thus proving that AAFA paste has high potential to be applied in seawater and freshwater applications.
Determination of process contaminants 2- and 3-MCPD esters and glycidyl esters in palm-based glycerol by indirect analysis using GC-MS

Ramli NAS, Roslan NA, Abdullah F, Bilal B, Ghazali R, Abd Razak RA, et al.

Food Addit Contam Part A Chem Anal Control Expo Risk Assess, 2023 Oct;40(10):1307-1321.
PMID: 37682685 DOI: 10.1080/19440049.2023.2255290

Esters of 2- and 3-monochloropropanediol (2-MCPDE, 3-MCPDE) and glycidol (GE) are regarded as process contaminants that are found in refined vegetable oils and oil-based foods. Since glycerol is produced during fat splitting, saponification and biodiesel production, it is important to have methods for determining contaminants that might be formed during these processes. Due to the use of glycerol as a food additive, data on the presence of compounds of toxicological concern, including 3-MCPD, are of interest. This study focuses on modifying the indirect analysis of 2-MCPDE, 3-MCPDE and GE using GC-MS based on the AOCS Official Method Cd 29a-13, validating the modified method, and quantifying 2-MCPDE, 3-MCPDE and GE in glycerol. The AOCS Cd 29a-13 method was modified at the initial stage of sample preparation in which the targeted esters were extracted from glycerol by vortex-assisted extraction before sample analysis. This modification was performed based on the polarity of all compounds involved. The calibration functions for all analytes were fitted to linear regression with R2 above 0.99. Limits of detection (LOD) 0.02, 0.01 and 0.02 mg kg-1 were obtained for 2-MCPDE, 3-MCPDE and GE, respectively. Spiked glycerol with 3-MCPDE and 2-MCPDE (0.25, 0.51 and 1.01 mg kg-1) and GE (0.58, 1.16 and 2.32 mg kg-1) were used for recovery and precision measurements. Recoveries of 100-108%, 101-103%, and 93-99% were obtained for 2-MCPDE, 3-MCPDE and GE, respectively. Acceptable precision levels with relative standard deviations ranged from 3.3% to 8.3% were obtained for repeatability and intermediate precision. The validated method was successfully applied for the analysis of the target compounds in refined glycerol from commercial plants, which showed that 2-MCPDE, 3-MCPDE and GE levels in the analysed samples were below the detection limit.
Fulltext Mechanical Properties of Fly Ash-Based Geopolymer Concrete Incorporation Nylon66 Fiber

Yazid MH, Faris MA, Abdullah MMAB, Ibrahim MSI, Razak RA, Burduhos Nergis DD, et al.

Materials (Basel), 2022 Dec 18;15(24).
PMID: 36556857 DOI: 10.3390/ma15249050

This study was carried out to investigate the effect of the diamond-shaped Interlocking Chain Plastic Bead (ICPB) on fiber-reinforced fly ash-based geopolymer concrete. In this study, geopolymer concrete was produced using fly ash, NaOH, silicate, aggregate, and nylon66 fibers. Characterization of fly ash-based geopolymers (FGP) and fly ash-based geopolymer concrete (FRGPC) included chemical composition via XRF, functional group analysis via FTIR, compressive strength determination, flexural strength, density, slump test, and water absorption. The percentage of fiber volume added to FRGPC and FGP varied from 0% to 0.5%, and 1.5% to 2.0%. From the results obtained, it was found that ICBP fiber led to a negative result for FGP at 28 days but showed a better performance in FRGPC reinforced fiber at 28 and 90 days compared to plain geopolymer concrete. Meanwhile, NFRPGC showed that the optimum result was obtained with 0.5% of fiber addition due to the compressive strength performance at 28 days and 90 days, which were 67.7 MPa and 970.13 MPa, respectively. Similar results were observed for flexural strength, where 0.5% fiber addition resulted in the highest strength at 28 and 90 days (4.43 MPa and 4.99 MPa, respectively), and the strength performance began to decline after 0.5% fiber addition. According to the results of the slump test, an increase in fiber addition decreases the workability of geopolymer concrete. Density and water absorption, however, increase proportionally with the amount of fiber added. Therefore, diamond-shaped ICPB fiber in geopolymer concrete exhibits superior compressive and flexural strength.
Fulltext Mechanical Performance, Microstructure, and Porosity Evolution of Fly Ash Geopolymer after Ten Years of Curing Age

Aziz IHA, Abdullah MMAB, Razak RA, Yahya Z, Salleh MAAM, Chaiprapa J, et al.

Materials (Basel), 2023 Jan 27;16(3).
PMID: 36770104 DOI: 10.3390/ma16031096

This paper elucidates the mechanical performance, microstructure, and porosity evolution of fly ash geopolymer after 10 years of curing age. Given their wide range of applications, understanding the microstructure of geopolymers is critical for their long-term use. The outcome of fly ash geopolymer on mechanical performance and microstructural characteristics was compared between 28 days of curing (FA28D) and after 10 years of curing age (FA10Y) at similar mixing designs. The results of this work reveal that the FA10Y has a beneficial effect on strength development and denser microstructure compared to FA28D. The total porosity of FA10Y was also lower than FA28D due to the anorthite formation resulting in the compacted matrix. After 10 years of curing age, the 3D pore distribution showed a considerable decrease in the range of 5-30 µm with the formation of isolated and intergranular holes.
Fulltext Differential coding of perception in the world's languages

Majid A, Roberts SG, Cilissen L, Emmorey K, Nicodemus B, O'Grady L, et al.

Proc Natl Acad Sci U S A, 2018 Nov 06;115(45):11369-11376.
PMID: 30397135 DOI: 10.1073/pnas.1720419115

Is there a universal hierarchy of the senses, such that some senses (e.g., vision) are more accessible to consciousness and linguistic description than others (e.g., smell)? The long-standing presumption in Western thought has been that vision and audition are more objective than the other senses, serving as the basis of knowledge and understanding, whereas touch, taste, and smell are crude and of little value. This predicts that humans ought to be better at communicating about sight and hearing than the other senses, and decades of work based on English and related languages certainly suggests this is true. However, how well does this reflect the diversity of languages and communities worldwide? To test whether there is a universal hierarchy of the senses, stimuli from the five basic senses were used to elicit descriptions in 20 diverse languages, including 3 unrelated sign languages. We found that languages differ fundamentally in which sensory domains they linguistically code systematically, and how they do so. The tendency for better coding in some domains can be explained in part by cultural preoccupations. Although languages seem free to elaborate specific sensory domains, some general tendencies emerge: for example, with some exceptions, smell is poorly coded. The surprise is that, despite the gradual phylogenetic accumulation of the senses, and the imbalances in the neural tissue dedicated to them, no single hierarchy of the senses imposes itself upon language.

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