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Effect of persulfate and persulfate/H₂O₂ on biodegradability of an anaerobic stabilized landfill leachate

Hilles AH, Abu Amr SS, Hussein RA, Arafa AI, El-Sebaie OD

Waste Manag, 2015 Oct;44:172-7.
PMID: 26248486 DOI: 10.1016/j.wasman.2015.07.046

The current study investigated the effects of S2O8(2-) and S2O8(2-)/H2O2 oxidation processes on the biodegradable characteristics of an anaerobic stabilized leachate. Total COD removal efficiency was found to be 46% after S2O8(2-) oxidation (using 4.2 g S2O8(2-)/1g COD0, at pH 7, for 60 min reaction time and at 350 rpm shaking speed), and improved to 81% following S2O8(2-)/H2O2 oxidation process (using 5.88 g S2O8(2-) dosage, 8.63 g H2O2 dosage, at pH 11 and for 120 min reaction time at 350 rpm). Biodegradability in terms of BOD5/COD ratio of the leachate enhanced from 0.09 to 0.1 and to 0.17 following S2O8(2-) and S2O8(2-)/H2O2 oxidation processes, respectively. The fractions of COD were determined before and after each oxidation processes (S2O8(2-) and S2O8(2-)/H2O2). The fraction of biodegradable COD(bi) increased from 36% in raw leachate to 57% and 68% after applying S2O8(2-) and S2O8(2-)/H2O2 oxidation, respectively. As for soluble COD(s), its removal efficiency was 39% and 78% following S2O8(2-) and S2O8(2-)/H2O2 oxidation, respectively. The maximum removal for particulate COD was 94% and was obtained after 120 min of S2O8(2-)/H2O2 oxidation. As a conclusion, S2O8(2-)/H2O2 oxidation could be an efficient method for improving the biodegradability of anaerobic stabilized leachate.

Matched MeSH terms: Reaction Time
Fulltext Preparation, optimization and swelling study of carboxymethyl sago starch (CMSS)-acid hydrogel

Tuan Mohamood NFA, Zainuddin N, Ahmad Ayob M, Tan SW

Chem Cent J, 2018 Dec 06;12(1):133.
PMID: 30523481 DOI: 10.1186/s13065-018-0500-8

In this study, sago starch was modified in order to enhance its physicochemical properties. Carboxymethylation was used to introduce a carboxymethyl group into a starch compound. The carboxymethyl sago starch (CMSS) was used to prepare smart hydrogel by adding acetic acid into the CMSS powder as the crosslinking agent. The degree of substitution of the CMSS obtained was 0.6410. The optimization was based on the gel content and degree of swelling of the hydrogel. In this research, four parameters were studied in order to optimize the formation of CMSS-acid hydrogel. The parameters were; CMSS concentration, acetic acid concentration, reaction time and reaction temperature. From the data analyzed, 76.69% of optimum gel content was obtained with 33.77 g/g of degree of swelling. Other than that, the swelling properties of CMSS-acid hydrogel in different media such as salt solution, different pH of phosphate buffer saline solution as well as acidic and alkaline solution were also investigated. The results showed that the CMSS-acid hydrogel swelled in both alkaline and salt solution, while in acidic or low pH solution, it tended to shrink and deswell. The production of the hydrogel as a smart material offers a lot of auspicious benefits in the future especially related to swelling behaviour and properties of the hydrogel in different types of media.

Matched MeSH terms: Reaction Time
Fulltext Enhanced fatty acid methyl esters recovery through a simple and rapid direct transesterification of freshly harvested biomass of Chlorella vulgaris and Messastrum gracile

Loh SH, Chen MK, Fauzi NS, Aziz A, Cha TS

Sci Rep, 2021 Feb 01;11(1):2720.
PMID: 33526809 DOI: 10.1038/s41598-021-81609-6

Conventional microalgae oil extraction applies physicochemical destruction of dry cell biomass prior to transesterification process to produce fatty acid methyl esters (FAMEs). This report presents a simple and rapid direct transesterification (DT) method for FAMEs production and fatty acid profiling of microalgae using freshly harvested biomass. Results revealed that the FAMEs recovered from Chlorella vulgaris were 50.1 and 68.3 mg with conventional oil-extraction-transesterification (OET) and DT method, respectively. While for Messastrum gracile, the FAMEs recovered, were 49.9 and 76.3 mg, respectively with OET and DT methods. This demonstrated that the DT method increased FAMEs recovery by 36.4% and 53.0% from C. vulgaris and M. gracile, respectively, as compared to OET method. Additionally, the DT method recovered a significantly higher amount of palmitic (C16:0) and stearic (C18:0) acids from both species, which indicated the important role of these fatty acids in the membranes of cells and organelles. The DT method performed very well using a small volume (5 mL) of fresh biomass coupled with a shorter reaction time (~ 15 min), thus making real-time monitoring of FAMEs and fatty acid accumulation in microalgae culture feasible.

Matched MeSH terms: Reaction Time
Fulltext Hybrid Symbiotic Organisms Search Optimization Algorithm for Scheduling of Tasks on Cloud Computing Environment

Abdullahi M, Ngadi MA

PLoS One, 2016;11(6):e0158229.
PMID: 27348127 DOI: 10.1371/journal.pone.0158229

Cloud computing has attracted significant attention from research community because of rapid migration rate of Information Technology services to its domain. Advances in virtualization technology has made cloud computing very popular as a result of easier deployment of application services. Tasks are submitted to cloud datacenters to be processed on pay as you go fashion. Task scheduling is one the significant research challenges in cloud computing environment. The current formulation of task scheduling problems has been shown to be NP-complete, hence finding the exact solution especially for large problem sizes is intractable. The heterogeneous and dynamic feature of cloud resources makes optimum task scheduling non-trivial. Therefore, efficient task scheduling algorithms are required for optimum resource utilization. Symbiotic Organisms Search (SOS) has been shown to perform competitively with Particle Swarm Optimization (PSO). The aim of this study is to optimize task scheduling in cloud computing environment based on a proposed Simulated Annealing (SA) based SOS (SASOS) in order to improve the convergence rate and quality of solution of SOS. The SOS algorithm has a strong global exploration capability and uses fewer parameters. The systematic reasoning ability of SA is employed to find better solutions on local solution regions, hence, adding exploration ability to SOS. Also, a fitness function is proposed which takes into account the utilization level of virtual machines (VMs) which reduced makespan and degree of imbalance among VMs. CloudSim toolkit was used to evaluate the efficiency of the proposed method using both synthetic and standard workload. Results of simulation showed that hybrid SOS performs better than SOS in terms of convergence speed, response time, degree of imbalance, and makespan.

Matched MeSH terms: Reaction Time
Effect of BaAl2O4 addition on power consumption and oxygen sensing response of Er123 ceramic rods utilizing hot-spot phenomenon

Hassan M, Yahya A, Okamoto T

Sains Malaysiana, 2011;40.

In this paper, we report the effect of BaAl2O4 addition (0-30 wt. %) on power consumption and oxygen sensing response of hot-spots developed on short Er123 ceramic rods of around 12 mm length synthesized using standard solid-state reaction. All the sensor rods showed increase in output current with increasing voltage followed by sudden reduction in output current and appearance of hot spot. After appearance of hot spot, for each rod, output current was observed to decrease gradually with increasing voltage with the slope of the I-V curve gradually approaching zero. Output current after the hot spot formation showed sensitivity to oxygen partial pressure, pO2 between 1 to 100 kPa. Addition of 30 wt. % BaAl2O4 reduced the fluctuation of current and increased the sensitivity for pO2 below 10 kPa. In addition, overshoot current was also reduced and resulted in improvement of response time from around 10 s to 5 s. Our result also showed that minimum power consumption was significantly reduced in the Er123 rods with 30 wt. % BaAl2O4.

Matched MeSH terms: Reaction Time
Synthesis of iron oxide (Fe304) magnetic nanocrystals by green chemistry approach

Chiu W, Too S, Daud S, Rashid N, Chia M, Rahman S, et al.

Sains Malaysiana, 2014;43:941-945.

In the present study, we report the size distribution study on the iron oxide (Fe304) magnetic nanocrystals (Ncs), which have been synthesized by using green chemistry approach with palm-oil based carboxylic compound (oleic acid) as capping ligands . The Fe304 Ncs were prepared by one pot reaction under non-hydrolytic approach. With the assistance of oleic acid that plays the role as effective capping-ligands , we showed that the Fe304 NCs that are highly monodispersed in size and shape can be synthesized by scrupulously controlling the reaction time. The diameter of Fe304 Ncs can be tuned within the range of 4.0-18.0 nm and exhibit very uniform morphology, which are spherical in shape. Current synthetic approach offers a cheap, environmentally benign and excellent repeatability route in large-scale production of high-quality magnetic Fe304 Ncs if compared to the preceding reports.

Matched MeSH terms: Reaction Time
An optimization study for transesterification of palm oil using Response Surface Methodology (RSM)

Wong Y, Taufiq-Yap YH, Ramli I

Sains Malaysiana, 2015;44:281-290.

Biodiesel was produced via transesterification of palm oil with methanol in the presence of CaO-Nb2O5 mixed oxide catalyst. Response surface methodology (RSM) with central composite design (CCD) was performed to determine the optimum operating conditions and to optimize the biodiesel yield. In this study, the reaction variables being optimized were reaction time, catalyst loading and methanol to oil molar ratio. From the analysis of variance (ANOVA), the most influential parameter on biodiesel production was reaction time. The predicted yield was found in good agreement with the experimental value, with R2= 0.9902. The optimum biodiesel yield of 97.67% was achieved at 2.67 h reaction time, with 3.60 wt. % of catalyst and with methanol to oil molar ratio of 13.04. The high biodiesel yield can be correlated to the synergic effect of basicity between the metallic ions of CaO-Nb2O5 shown in the physicochemical analysis.

Matched MeSH terms: Reaction Time
Looking at remembering: Eye movements, pupil size, and autobiographical memory

Janssen SMJ, Foo A, Johnson SN, Lim A, Satel J

Conscious Cogn, 2021 03;89:103089.
PMID: 33607423 DOI: 10.1016/j.concog.2021.103089

To examine the relationship between visual imagery and autobiographical memory, eye position and pupil size were recorded while participants first searched for memories and then reconstructed the retrieved memories (Experiment 1), or only searched for memories (Experiment 2). In Experiment 1, we observed that, although recollective experience was not associated with the number of fixations per minute, memories that took longer to retrieve were linked to increased pupil size. In Experiment 2, we observed that directly retrieved memories were recalled more quickly and were accompanied by smaller pupils than generatively retrieved memories. After correcting for response time, retrieval mode also produced an effect, showing that decreased pupil size is not simply due to directly retrieved memories being recalled more quickly. These findings provide compelling evidence that objective measures, such as pupil size, can be used alongside subjective measures, such as self-reports, to distinguish between directly retrieved and generatively retrieved memories.

Matched MeSH terms: Reaction Time
Differences in right hemisphere fNIRS activation associated with executive network during performance of the lateralized attention network tast by elite, expert and novice ice hockey athletes

Yu M, Xu S, Hu H, Li S, Yang G

Behav Brain Res, 2023 Apr 12;443:114209.
PMID: 36368444 DOI: 10.1016/j.bbr.2022.114209

OBJECTIVE: We investigated brain activity associated with executive control attention network in elite, expert, and novice female ice hockey athletes during the revised lateralized attention network tast to determine whether the neural correlates of performance differ by skill level.
METHODS: We collected and analyzed functional near-infrared spectroscopy data of 38 participants while performing the revised lateralized attention network tast.
RESULTS: Elite players were significantly faster than novices (p = .005), and the experts' overall accuracy rate (ACC) was higher than that of novices (p = .001). The effect of the executive network on reaction time was higher in novices than in elite players (p = .008) and experts (p = .004). The effect of the executive network on the ACC was lower in elite players than in experts (p = .009) and novices (p = .010). Finally, elite player had higher flanker conflict effects on RT (p = .005) under the invalid cue condition. the effect of the alertness network and orientation on the ACC was lower in elite players than in novices (p = .000) and experts (p = .022). Changes in the blood oxygen level-dependent signal related to the flanker effect were significantly different in the right dorsolateral prefrontal cortex (F=3.980, p = .028) and right inferior frontal gyrus (F=3.703, p = .035) among the three groups. Elit players showed more efficient executive control (reduced conflict effect on ACC) (p = .006)in the RH.The changes related to the effect of blood oxygen level on orienting were significantly different in the right frontal eye fields (F=3.883, p = .030) among the three groups, Accompanied by significant activation of the right dorsolateral prefrontal cortex(p = .026).
CONCLUSION: Our findings provide partial evidence of the superior cognitive performance and high neural efficiency of elite ice hockey players during cognitive tasks. These results demonstrate the right hemisphere superiority for executive control.We also found that specific brain activation in hockey players does not show a clear and linear relationship with skill level.

Matched MeSH terms: Reaction Time
Fulltext Optimisation and Characterisation of Lipase-Catalysed Synthesis of a Kojic Monooleate Ester in a Solvent-Free System by Response Surface Methodology

Jumbri K, Al-Haniff Rozy MF, Ashari SE, Mohamad R, Basri M, Fard Masoumi HR

PLoS One, 2015;10(12):e0144664.
PMID: 26657030 DOI: 10.1371/journal.pone.0144664

Kojic acid is widely used to inhibit the browning effect of tyrosinase in cosmetic and food industries. In this work, synthesis of kojic monooleate ester (KMO) was carried out using lipase-catalysed esterification of kojic acid and oleic acid in a solvent-free system. Response Surface Methodology (RSM) based on central composite rotatable design (CCRD) was used to optimise the main important reaction variables, such as enzyme amount, reaction temperature, substrate molar ratio, and reaction time along with immobilised lipase from Candida Antarctica (Novozym 435) as a biocatalyst. The RSM data indicated that the reaction temperature was less significant in comparison to other factors for the production of a KMO ester. By using this statistical analysis, a quadratic model was developed in order to correlate the preparation variable to the response (reaction yield). The optimum conditions for the enzymatic synthesis of KMO were as follows: an enzyme amount of 2.0 wt%, reaction temperature of 83.69°C, substrate molar ratio of 1:2.37 (mmole kojic acid:oleic acid) and a reaction time of 300.0 min. Under these conditions, the actual yield percentage obtained was 42.09%, which is comparably well with the maximum predicted value of 44.46%. Under the optimal conditions, Novozym 435 could be reused for 5 cycles for KMO production percentage yield of at least 40%. The results demonstrated that statistical analysis using RSM can be used efficiently to optimise the production of a KMO ester. Moreover, the optimum conditions obtained can be applied to scale-up the process and minimise the cost.

Matched MeSH terms: Reaction Time
Fulltext Palm-based medium-and-long-chain triacylglycerol (P-MLCT): production via enzymatic interesterification and optimization using response surface methodology (RSM)

Lee YY, Tang TK, Phuah ET, Karim NA, Alwi SM, Lai OM

J Food Sci Technol, 2015 Feb;52(2):685-96.
PMID: 25694677 DOI: 10.1007/s13197-013-1065-0

Structured lipid such as medium-and long-chain triacylglycerol (MLCT) is claimed to be able to suppress body fat accumulation and be used to manage obesity. Response surface methodology (RSM) with four factors and three levels (+1,0,-1) faced centered composite design (FCCD) was employed for optimization of the enzymatic interesterification conditions of palm-based MLCT (P-MLCT) production. The effect of the four variables namely: substrate ratio palm kernel oil: palm oil, PKO:PO (40:60-100:0 w/w), temperature (50-70 °C), reaction time (0.5-7.5 h) and enzyme load (5-15 % w/w) on the P-MLCT yield (%) and by products (%) produced were investigated. The responses were determined via acylglycerol composition obtained from high performance liquid chromatography. Well-fitted models were successfully established for both responses: P-MLCT yield (R (2) = 0.9979) and by-products (R (2) = 0.9892). The P-MLCT yield was significantly (P reaction time and reaction temperature but not enzyme load (P > 0.05). Substrate ratio PKO: PO (100:0 w/w) gave the highest yield of P-MLCT (61 %). Nonetheless, substrate ratio of PKO: PO (90:10w/w) was chosen to improve the fatty acid composition of the P-MLCT. The optimized conditions for substrate ratio PKO: PO (90:10 w/w) was 7.26 h, 50 °C and 5 % (w/w) Lipozyme TLIM lipase, which managed to give 60 % yields of P-MLCT. Up scaled results in stirred tank batch reactor gave similar yields as lab scale. A 20 % increase in P-MLCT yield was obtained via RSM. The effect of enzymatic interesterification on the physicochemical properties of PKO:PO (90:10 w/w) were also studied. Thermoprofile showed that the P-MLCT oil melted below body temperature of 37 °C.

Matched MeSH terms: Reaction Time
Development of prototype heterogeneous chitosan membrane using different plasticizer for glutamate sensing

Isa IM, Ab Ghani S

Talanta, 2007 Jan 15;71(1):452-5.
PMID: 19071326 DOI: 10.1016/j.talanta.2006.04.034

This paper describes the preparation of and experimentation undertaken by heterogeneous chitosan membrane as ion selective electrode for glutamate ion. The linearity response was obtained in the range of 1.0x10(-5) to 1.0x10(-1)M with a detection limit of 1.0x10(-6)M. The performance of the electrode was found in the pH range of 4.0-8.0 at temperature 25+/-3 degrees C. The response time was at 5-35s and was useful for a period of more than 4 months. The selectivity values towards some anions indicates good selectivity over a number of interfering anions. No significant improvement of membrane performance over additional of plasticizers such as 2-NPOE, BEHA and DOPP. The electrodes gave sufficient Nernstian responses with the exception of membrane with 2-NPOE.

Matched MeSH terms: Reaction Time
Performance of combined sodium persulfate/H2O2 based advanced oxidation process in stabilized landfill leachate treatment

Hilles AH, Abu Amr SS, Hussein RA, El-Sebaie OD, Arafa AI

J Environ Manage, 2016 Jan 15;166:493-8.
PMID: 26580899 DOI: 10.1016/j.jenvman.2015.10.051

A combination of persulfate and hydrogen peroxide (S2O8(2-)/H2O2) was used to oxidizelandfill leachate. The reaction was performed under varying S2O8(2-)/H2O2 ratio (g/g), S2O8(2-)/H2O2 dosages (g/g), pH, and reaction time (minutes), so as to determine the optimum operational conditions. Results indicated that under optimum operational conditions (i.e. 120 min of oxidation using a S2O8(2-)/H2O2 ratio of 1 g/1.47 g at a persulfate and hydrogen peroxide dosage of 5.88 g/50 ml and8.63 g/50 ml respectively, at pH 11) removal of 81% COD and 83% NH3-N was achieved. In addition, the biodegradability (BOD5/COD ratio) of the leachate was improved from 0.09 to 0.17. The results obtained from the combined use of (S2O8(2-)/H2O2) were compared with those obtained with sodium persulfate only, hydrogen peroxide only and sodium persulfate followed by hydrogen peroxide. The combined method (S2O8(2-)/H2O2) achieved higher removal efficiencies for COD and NH3-N compared with the other methods using a single oxidizing agent. Additionally, the study has proved that the combination of S2O8(2-)/H2O2 is more efficient than the sequential use of sodium persulfate followed by hydrogen peroxide in advanced oxidation processes aiming at treatingstabilizedlandfill leachate.

Matched MeSH terms: Reaction Time
Synthesis of fatty acid methyl ester from the transesterification of high- and low-acid-content crude palm oil (Elaeis guineensis) and karanj oil (Pongamia pinnata) over a calcium-lanthanum-aluminum mixed-oxides catalyst

Syamsuddin Y, Murat MN, Hameed BH

Bioresour Technol, 2016 Aug;214:248-52.
PMID: 27136612 DOI: 10.1016/j.biortech.2016.04.083

The synthesis of fatty acid methyl ester (FAME) from the high- and low-acid-content feedstock of crude palm oil (CPO) and karanj oil (KO) was conducted over CaO-La2O3-Al2O3 mixed-oxide catalyst. Various reaction parameters were investigated using a batch reactor to identify the best reaction condition that results in the highest FAME yield for each type of oil. The transesterification of CPO resulted in a 97.81% FAME yield with the process conditions of 170°C reaction temperature, 15:1 DMC-to-CPO molar ratio, 180min reaction time, and 10wt.% catalyst loading. The transesterification of KO resulted in a 96.77% FAME yield with the conditions of 150°C reaction temperature, 9:1 DMC-to-KO molar ratio, 180min reaction time, and 5wt.% catalyst loading. The properties of both products met the ASTM D6751 and EN 14214 standard requirements. The above results showed that the CaO-La2O3-Al2O3 mixed-oxide catalyst was suitable for high- and low-acid-content vegetable oil.

Matched MeSH terms: Reaction Time
Fulltext The effect of Ramadan fasting on spatial attention through emotional stimuli

Molavi M, Yunus J, Utama NP

Psychol Res Behav Manag, 2016;9:105-14.
PMID: 27307772 DOI: 10.2147/PRBM.S100495

Fasting can influence psychological and mental states. In the current study, the effect of periodical fasting on the process of emotion through gazed facial expression as a realistic multisource of social information was investigated for the first time. The dynamic cue-target task was applied via behavior and event-related potential measurements for 40 participants to reveal the temporal and spatial brain activities - before, during, and after fasting periods. The significance of fasting included several effects. The amplitude of the N1 component decreased over the centroparietal scalp during fasting. Furthermore, the reaction time during the fasting period decreased. The self-measurement of deficit arousal as well as the mood increased during the fasting period. There was a significant contralateral alteration of P1 over occipital area for the happy facial expression stimuli. The significant effect of gazed expression and its interaction with the emotional stimuli was indicated by the amplitude of N1. Furthermore, the findings of the study approved the validity effect as a congruency between gaze and target position, as indicated by the increment of P3 amplitude over centroparietal area as well as slower reaction time from behavioral response data during incongruency or invalid condition between gaze and target position compared with those during valid condition. Results of this study proved that attention to facial expression stimuli as a kind of communicative social signal was affected by fasting. Also, fasting improved the mood of practitioners. Moreover, findings from the behavioral and event-related potential data analyses indicated that the neural dynamics of facial emotion are processed faster than that of gazing, as the participants tended to react faster and prefer to relay on the type of facial emotions than to gaze direction while doing the task. Because of happy facial expression stimuli, right hemisphere activation was more than that of the left hemisphere. It indicated the consistency of the emotional lateralization concept rather than the valence concept of emotional processing.

Matched MeSH terms: Reaction Time
Fulltext Silver (I) Dicyanonitrosomethanide, Ag[ONC(CN)2] Complex as Catalyst for the Selective Oxidation of Styrene to Benzaldehyde

Mohammad Anwar Mohamed Iqbal, Muhammad Zulhelmi Nazri, Mohammad Norazmi Ahmad, Erna Normaya Abdullah, Umie Fatihah Mohamad Haziz, Mohd Rizal Razali, et al.

Science Letters, 2020;14(2):71-84.
MyJurnal

Silver (I) dicyanonitrosomethanide, Ag[ONC(CN)2] represent a 3D interwoven coordination polymer organization in which all the donor atoms of the functional groups of ONC(CN)2- are coordinated to the Ag(I). Oxidation of styrene utilizing H2O2 as an oxidant in acetonitrile (CH3CN) was used as a model reaction to investigate the catalytic potential of the Ag (I) complex. The CH3CN was chosen as the solvent based on the data collected from Conductor like Screening Model for Real Solvents (COSMO-RS) study. The data indicate that the Ag [ONC(CN)2] complex was compatible and soluble in CH3CN. Different parameters such as styrene:H2O2 molar ratio, reaction time, catalyst mass, and reaction temperature were studied. Highest styrene conversion (36%) with 100% selectivity towards benzaldehyde (BZ) was achieved when 25 mg catalyst, 1:1 styrene to H2O2 molar ratio were used. The reaction was carried out at 303 K for 3 h. The catalytic conversion of styrene to BZ is proposed to take place via [Ag-H2O2] adduct with styrene oxide (StO) as an intermediate. Molecular Electrostatic Potential (MEP) shows that the Ag atom has the highest probability to coordinate with the oxygen atom of H2O2. The MEP data confirms the proposed mechanism.

Matched MeSH terms: Reaction Time
Fulltext An acceleration of microwave-assisted transesterification of palm oil-based methyl ester into trimethylolpropane ester

Aziz NAM, Yunus R, Hamid HA, Ghassan AAK, Omar R, Rashid U, et al.

Sci Rep, 2020 11 12;10(1):19652.
PMID: 33184363 DOI: 10.1038/s41598-020-76775-y

Microwave-assisted synthesis is known to accelerate the transesterification process and address the issues associated with the conventional thermal process, such as the processing time and the energy input requirement. Herein, the effect of microwave irradiation on the transesterification of palm oil methyl ester (PME) with trimethylolpropane (TMP) was evaluated. The reaction system was investigated through five process parameters, which were reaction temperature, catalyst, time, molar ratio of TMP to PME and vacuum pressure. The yield of TMP triester at 66.9 wt.% and undesirable fatty soap at 17.4% were obtained at 130 °C, 10 mbar, sodium methoxide solution at 0.6 wt.%, 10 min reaction time and molar ratio of TMP to PME at 1:4. The transesterification of palm oil-based methyl ester to trimethylolpropane ester was 3.1 folds faster in the presence of microwave irradiation. The total energy requirement was markedly reduced as compared to the conventional heating method. The findings indicate that microwave-assisted transesterification could probably be an answer to the quest for a cheaper biodegradable biolubricant.

Matched MeSH terms: Reaction Time
Synthesis of large-area few-layer graphene by open-flame deposition

Edhuan Ismail, Mohd Shukri Sirat, Abd. Malek Abdul Hamid, Raihan Othman, Mohd Mohd Hanafi Ani, Asyadi Azam Mohd Abid

Sains Malaysiana, 2017;46:1011-1016.

Various production methods have been developed for graphene production, but each of them falls short in either the economic or quality aspect. In this paper, we present the flame deposition method, a modified chemical vapor deposition (CVD) that uses an open-flame. In this method, resulting carbon deposits were found to be graphitic in nature, thereby suggesting multilayer graphene growth in a very short reaction time of 5 min. Furthermore, the deposits were transferred onto a cyanoacrylate plastic substrate and its sheet resistance was measured to be 81 ohm/square. The results showed that open-flame deposition exhibits high potential for low-cost, low-energy and high-quality production of graphene.

Matched MeSH terms: Reaction Time
Fulltext Ambulance response time at three selected tertiary hospitals in Malaysia: performance of hospital-based ambulance equipped with computerized call centre system

Hussin, K., Hassan, M.R., Hamzah, M.L., Fadzli, A., Nik Mohamad, N.A., Nik Him, N.A.S.

Malaysian Journal of Applied Sciences, 2018;3(1):42-50.
MyJurnal

The importance of rapid ambulance response to emergency medical crises is undeniable. An early
access to advanced care is crucial to saving a life. Modern computerised call centre and the hospitalbased ambulance services are believed to enhance the quality of service delivery. However, whether
it will further reduce the ambulance response time is still debatable. A cross-sectional study was
conducted in June 2012 until July 2012 at three selected tertiary hospitals in Malaysia. The
ambulance response time was expressed in a median and interquartile range (IQR) and MannWhitney U test was used to determine the associations between types of ambulance and
computerised call centre system versus voice only. Wilcoxon Rank Sign Test was used to assess
the significance of means difference. A hospital-based ambulance had the median time of 0.19
minutes while community-based ambulance had the median time of 0.20 minutes (The Z score -
0.916, p-value - 0.360). The hospital with computer call centre had the median time of 0.19 minutes
while hospital without computer call centre had the median of 0.20 minutes (The Z score - 0.816, P
value - 0.414).The response time of hospital-based ambulance equipped with computerised call
centre system was comparable in three selected tertiary hospitals in Malaysia.

Matched MeSH terms: Reaction Time
Fulltext Pre-hospital emergency medical service response time phenomenon in Klang valley: an answer for the society

MOHD SAID NURUMAL

Malaysian Journal of Qualitative Research, 2017;4(1):17-32.
MyJurnal

This qualitative descriptive study, underpinned by naturalistic inquiry, explored the prehospital emergency medical service response time in Klang Valley by providing an in-depth information of the phenomenon. In this study, various levels of health care personnel participated in focus group discussion and semi-structured interview. The staff members consisted of many levels of category from the lower ranks up to the higher level administrative officers. Content analysis was employed in analysing all data. Every one of the key informants was aware of the importance of making immediate responses to each ambulance call received. They shared their thoughts, experiences, and challenges in achieving the ideal response time in line with international recommendations. There were five categories of issues that emerged and challenges that arose from delays in response time, namely, 1) insufficient key information; 2) inconsistent information leading to delayed arrival of ambulance; 3) traffic condition causing delay in ambulance speed; 4) lack of resources contributing to an increase in workload; and, 5) unassertiveness in the attitude of members of staff. The findings have provided an answer to the society with regard to the current pre-hospital emergency medical service issues related to delay in the service delivered. Thus, policy makers and pre-hospital health care service providers should develop a strategic action plan by focusing on these findings to reduce the response time of ambulance call.

Matched MeSH terms: Reaction Time

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