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Peroxide assisted adsorption for treating palm oil mill effluent using palm shell based activated carbon / Kwong Chia Jun
No full textIn Malaysia, palm oil production is one of the major agricultural industries, attributing 37.9 % of the agricultural contribution to Gross domestic product (GDP). Among them, POME is the largest wastes generated from the palm oil mills production with high BOD, COD, TS, TSS, colour more than 500 ADMI. Since POME is considered as highly recalcitrant, the Department of Environment is started to be more stringent in standard discharge limits to control water pollution. Therefore, this study aimed to develop green hybrid adsorbent from activated PKS by integrating iron oxide and zeolite to treat POME. Palm kernel shell-based activated carbon (PKSAC) was incorporated with zeolite and iron oxide (Fe) to synthesize Zeolite-Fe/PKSAC and Fe/PKSAC adsorbents. The adsorbents have been prepared using co-precipitation and ultrasonic-assisted mixing processes and analyzed for surface functional group, morphology, N2 adsorption porosity, magnetic properties, and stability. The result showed that Zeolite-Fe/PKSAC and Fe/PKSAC have predominant mesoporous structures with a high surface area up to 619 m2/g for Fe/PKSAC and 573 m2/g for Zeolite-Fe/PKSAC. Both adsorbents also illustrated a high magnetic saturation of 16.6 emu/g and 10.6 emu/g for Fe/PKSAC and Zeolite-Fe/PKSAC, respectively.
The adsorption efficiency of both adsorbents was investigated with and without the addition of H2O2 for POME removal. The effects of operating parameters that include H2O2 dosage, adsorbent dosage, contact time and initial pH of solution on the adsorption process, were investigated. The adsorption study using Fe/PKSAC without H2O2 showed that Fe/PKSAC had higher colour removal (93 %) than Zeolite-Fe/PKSAC (88 %) 5 g/L
of adsorbent was used at pH 3 for 40 min of contact time. However, Zeolite-Fe/PKSAC revealed a higher chemical oxygen demand removal of 63 % compared to Fe/PKSAC (58 %). The reusability analysis also indicated that Zeolite-Fe/PKSAC has higher stability as it maintains its adsorbent capacity over five cycles, with just a decrease of 6 % compared to Fe/PKSAC. The adsorption of POME using Zeolite-Fe/PKSAC and H2O2 had successfully removed 83 % colour and 67 % COD using a lesser amount of adsorbent of 4 g/L and H2O2 of 68 mM, within a shorter reaction time of 30 minutes compared to Fe/PKSAC. Besides, Zeolite-Fe/PKSAC+H2O2 found to maintain its adsorbent potential up to the 5th cycle with a reduction of just 3 % of adsorption efficiency compared to Fe/PKSAC+ H2O2 (7 %). Zeolite-Fe/PKSAC+H2O2 also achieved the highest adsorption capacity of 73 mg/g as compared to Fe/PKSAC+H2O2 (55 mg/g), Zeolite-Fe/PKSAC (48 mg/g) and Fe/PKSAC (44 mg/g).
In conclusion, the study has proven that the incorporation of iron oxide and zeolite into palm kernel shell activated carbon enhances the stability, separability and surface area of the adsorbents. The peroxide-assisted adsorption process using Zeolite-Fe/PKSAC greatly improved the reusability and adsorption efficiency of the adsorbent, minimizing the dosage of the adsorbent while reducing contact time
Development of poly (methyl methacrylate-co-methacrylic acid) based electrolytes with synthesized and commercial ionic liquids for dye sensitized solar cells / Vhaissnavi Sundararajan
No full textA persistent challenge for expanding global population and soaring economic progress has always been ensuring everyone has enough access to energy supply. At present, the high dependency on fossil fuel derived energy has led to a crisis that necessitated a shift of attention towards greener energy sources like solar. Solar energy serves as the most consistent back up energy and the best option for environmental conservation. Among the listed solar harvesters, dye sensitized solar cells (DSSCs) bring about vast potential in efficient conversion of solar to electrical energy. The fact that this discovery has not reached its pinnacle and every constituent of the cell still needs working on, a popular research interest would be the replacement of liquid electrolytes with gel polymer counterparts. Being a hybrid, gel polymer electrolytes (GPEs) retain the cohesive nature of solid electrolytes and stay diffusive as liquid electrolytes producing reasonable ionic conductivity and maintains good contact between components within the DSSCs., In that perspective, this work examines a series of poly(methyl methacrylate-co-methacrylic acid) P(MMA-co-MAA) based PE system for DSSCs. Initial sample preparation steps were modified by varying the ratio of I2/I3ˉ redox mediator from a sodium salt, copolymer and solvent used. As a part of secondary electrolyte systems studied, novel quinolinium based ionic liquids (ILs) were incorporated to the best single salt system. Great care was taken during the synthesis and purification of N-butyl-6-methylquinolinium bis(trifluoromethylsulfonyl) imide [C4mquin][NTf2] and N-butyl-6-methylquinolinium iodide [C4mquin][I] ILs in order to achieve low impurity levels. Exploring the new cation-anion combined IL for the purpose of DSSCs was necessary to achieve better and more sustained electrolyte conductivity. Subsequently, the prepared electrolyte mixtures were tested with a standard DSSC configuration of glass/FTO/TiO2/N719 dye/electrolyte/Pt/FTO/glass with active area of 0.3 cm2. The single salt system samples were able to achieve highest ionic conductivity and power conversion efficiency (PCE) of 1.07 mS cm-1 and 2.34%, respectively. Remarkably, upon the addition of the quinolinium IL, the ionic conductivity and PCE had increased to 2.26 mS cm-1 and 5.67%, respectively for [C4mquin][NTf2] and 2.64 mS cm-1 and 4.98%, respectively for [C4mquin][I] at its optimum concentration. As to emphasis the role of novel quinolinium based IL containing electrolytes in DSSCs, the efficiency of these cells were compared with DSSCs assembled with a commercialized a used imidazolium IL, [C6mim][I] which recorded a maximum ionic conductivity of 2.23 mS cm-1 with PCE of 5.30%. The developed polymer electrolyte samples were also characterized with X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR) and Thermogravitimetry Analyzer (TGA). As an additional diagnosis to understand the performance and electrochemical properties of PEs in DSSCs, electrochemical impedance studies were conducted to elucidate charge transfer processes occurring at interfacial within the cell. The performance of the quinolinium containing DSSCs has been improved by enhanced electron transport properties, reduced charge recombination and increased electron lifetime. Overall, the quinolinium based PEs prepared have performed better than anticipated, considering the sole participation with a single salt system, the bulkiness of cation present and quasi-solid nature unlike most commercially available ILs
Nanosecond and femtosecond fiber lasers using tungsten trioxide, poly (3,4-ethylenedioxythiophene) polystyrene sulfonate and turmeric saturable absorbers / Ahmed Shakir Abdullah Abdullah
Get PDFNanosecond and femtosecond fiber lasers have been intensively investigated in recent years for applications in material processing, imaging, and medical treatment because of the low thermal effect and high pulse energy. Passive techniques based on saturable absorber (SA) offer advantages over their active counterparts due to their unique electronic and optical properties as well as no need of external electrical modulation. This work was successfully explored three new materials: tungsten tri-oxide, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT: PSS), and turmeric [1, 7-bis (4-hydroxy-3-methoxyphenyl)-1, 6 heptadiene-3, 5-dione] as the passive SA. These SAs were successfully fabricated, characterized, and utilized in generating Q-switched and mode-locked pulses in various fiber laser cavities. The highest modulation depth of 50 % was obtained by the organic SA fabricated by embedding PEDOT: PSS into PVA film. Various Q-switched fiber lasers were also demonstrated based on the newly developed SAs. For instance, Q-switched YDFL operating at 1063.78 nm was demonstrated using WO3 PVA thin film as SA. It generated Q-switched pulses with the maximum repetition rate of 39.79 kHz, minimum pulse width of 2.37 μs and maximum pulse energy of 625 nJ. The lowest pulse width of 580 ns was obtained with the organic SA based PEDOT: PSS embedded into PVA film. Various mode-locked fiber lasers operating in picosecond and femtosecond regimes were also realized using the newly developed SAs. At optimized design with a cavity length of 22.5 m, a soliton femtosecond pulse with 460 fs pulse width and peak power of 4.27 kW, was successfully achieved. This work has also successfully drawn attention to the potentials that organic materials have in fiber laser selakan-mod. Mereka serasi dengan bio, mesra alam, ringan dan fleksibel secara mekanikal
The impact of institutional factors and IFRS on the value relevance of accounting information: Evidence from ah shares / Zou Feng
No full textThe study investigates whether institutional factors affect the value relevance of accounting information of Chinese cross-listed firms during the years 2000 to 2013. It covers the last two sets of China's accounting standards – both the Accounting System for Business Enterprises (ASBE) released in 2001 and the revised version in 2006. Specifically, the study concentrates on whether the IFRS convergence is associated with the incremental improvement on the value relevance of accounting information, and how the institutional factors affect the value relevance of these cross-listed firms. It is now well established from various studies that IFRS convergence would improve the corporate disclosure transparency and significantly enhance the quality of accounting information, especially the value relevance of accounting information. However, in the process of global convergence to IFRS, some studies found that institutional factors play a prominent role in affecting value relevance, particularly in emerging economies. Mainland China is communist and led by a one-party political system, while as an inalienable part of China, Hong Kong retains its financial system, legal system, and possesses its own currency. In this respect, the unique situation of Mainland China and Hong Kong embodies the principle of “one country, two systems” and enables the coexistence of socialism and capitalism in the same country. Therefore, because of these institutional differences, it might be expected that the value relevance of accounting information is different between Mainland China and Hong Kong listed firms. Furthermore, to create a side-by-side comparison, firms with twin listing of A-share and H-share are selected as the study sample. These Chinese cross-listed firms issue A-share can also issue H-share, and they are known as AH- shares. To take a close look at the mean differences in theses AH- shares between the pre- and post- IFRS convergence period, the study uses paired sample t-test where the time segment is divided into two equal periods. The result of the study indicates that IFRS convergence could indeed promote higher quality of accounting information, as the value relevance increases when firms switched from complying with the China GAAP to the IFRS-based accounting standards. Besides, the impact of institutional factors on the value relevance has been proved to be varied between Mainland China and Hong Kong stock market. This result suggests that regions with a strong and sound institutional framework and higher scores of the Worldwide Governance Indicators further support and enhance the neutrality of accounting information. Accordingly, such regions would correspond to a lower interventionist power in the financial reporting system and attract more investments. The study also shows that the IFRS convergence has successfully reduced the information asymmetry among Chinese cross-listed shares. In addition, the result finds that all six institutional factors (voice and accountability, political stability and absence of violence/terrorism, government effectiveness, regulatory quality, rule of law and control of corruption) are statistically significant in Mainland China, whereas only two (voice and accountability, regulatory quality) have been confirmed in Hong Kong
Site suitability study for recycling plastic plant / Hasbullah Hashim
No full textImportant site selection criteria include compatibility of land use and the adequacy of
recycling of industrial plastics is a major industry in the country. Site suitability
depends on the project's compatibility with local plans and gazette structures, as well as
the surrounding land use and setbacks. The site was gazette for industry activity because
of its topography and proximity to rubber plantations. Kota Trading, a manufacturer of
natural rubber in 1960, owns the land. Important site selection criteria include the
compatibility of land use and the adequacy of the buffer between the proposed industry
and activity and its neighbours, as these factors allow the selection of environmental
management options that avoid unnecessary investments in pollution control beyond
what is normally required. Identifying the types of receptors that are sensitive and the
primary criteria for site selection are principal factors in determining the best buffer for
recycling plastic industries. If you want to choose the best buffer between a source and a
receptor, you need to consider its nature, character, and response to an impact, among
other factors. Buffer distances are prescribed based on the potential to affect the
environment and the significance of the impacts on human health and environmental
conservation, and the industry standard used for pollution control
Wasl al-fiqh bi al-Hadith: Pelaksanaan di Dayah Tradisional Aceh / Lazuardi Muhammad Latif
No full textWasl al-Fiqh bi al-lfadith is a concept which integrates the study of jurisprudence and hadith so that fuqaha' will have access to better guidance in formulating their rulings. The concept will also help the muhaddithiun in deriving a more accurate interpretation of the hadith they study. Traditional dayah is the oldest Islamic educational institution in the Malay Archipelago, which is highly respectable among the people of Aceh and is often relied upon for religious rulings and Islamic teachings. This study, which was a field study, took place at Dayah Mudi Mesra, Samalanga, Aceh. It was selected as the site of the study due to its long-established reputation and great influence among the people of Aceh. The study was carried out to shed some light on the concept of Wasl al-Fiqh bi al-Hadith as discussed by Islamic scholars throughout the history of Islamic law, analyze the challenge of traditional dayah in implementing
the concept of Wasl al-Fiqh bi al-lfad/ih, analyze the role of Dayah Mudi Mesra in implementing the concept of Wasl al-Fiqh bi al-Hadith, and analyze the detailed aspects of its implementation and implications for the students and its alumni. The study employs a mixed method, combining qualitative and quantitative data collection instruments consisting of library data, interviews, questionnaires, observations, and documentation. Inductive, deductive, and comparative methods were used for data analysis. The study found, according to some historical accounts, that the concept of Wasl al-Fiqh bi al Hadith is actually a method to reinforce the use of hadith as the second source of law from which fiqh is derived. Overall, traditional dayah in Aceh still face challenges in combining the teaching of fiqh and hadith. Dayah Mudi Mesra, in particular, has not assumed a pivotal role in carrying out the task as it should have. The study also found that the implementation of this concept at dayah has been synonymous to the exclusive adoption of the mazhab of al-Shafi'i as learned from a number of Shafi' i books or as taught by some Shafi' i scholars as a primary reference. This has led to some negative implications both in the socio··religious aspect, such as the emergence of ghuluww in specific religious practices and the rejection of any possible differing\ opinions, and in the socio-political aspect, such as efforts to influence government officials or government policies and to take control of government's strategic positions in order to legitimatize certain religious practices and to force people into subscribing to such practices
Memory retention for multilingual note taking platform / Chandra Latha Ramachandran
No full textTechnology developments such as laptop, smartphone, and video lectures are altering pedagogy dynamics and influencing the way students compose and review notes. Confused on how to learn effectively have led to a lot of trial and error on the note taking methods between students. This study explore the effect of memorization retention using the pen, the laptop, and the smartphone on multilingual note taking which is in Malay (Jawi Script), English (Latin Script), Chinese (Hanzi script) and Tamil (Tamil script). A model of note taking is designed to assist in the development of an effective learning platform. A progressive web application (PWA) named MemRetz for mobile and laptops respectively were developed based on the designed model. During this analysis, about thirty participants for each language are given a group of articles and video in three different mediums that consists of various lengths of characters for each article and duration for each video. The note taken, medium used and memory retention score (percentage of correctness × time taken to complete the test) are recorded and measured to determine the effect of memorization retention using different mediums. Results proved that note taking does influence memory retention. However, different scripted language or medium used do not have an effect on memory retention score. Study’s results suggest that students may read article and take notes using any language or medium they prefer and comfortable with as it does not affect the memory retention. The usage of note-taking software in an E-learning platform is useful since it increases participants' ability to take notes and helps them remember
Cellulose-based polymer electrolyte derived from waste coconut husk: Residual lignin as a natural plasticiser / Chua Kai Ying
No full textPolymer electrolyte (PE) finds many applications in the fabrication of electrochemical devices such as batteries, solar cells, supercapacitors, and electrochromic windows. The usage of cellulose from the waste of coconut husk is one alternative in using natural polymer as a green electrolyte. However, due to its high crystallinity, the usage of plasticiser is advantageous to reduce the crystallinity of cellulose. Lignin which co-exists with cellulose in the cell walls of the plants could act as a natural plasticiser in preparing a good polymer electrolyte. In this work, cellulose was isolated from waste coconut husk (Cocos nucifera), modified into water-soluble carboxymethylcellulose (CMC) and then made into a film by solvent-casting method. The chemical compositions of the cellulose fibre after each chemical treatment were analysed, and the cellulose derivatives were characterised by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), thermogravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS). The cellulose fibre was found to have major removal of hemicellulose and lignin with one-time alkali treatment followed by twice bleaching treatments. The thermal degradation of all cellulose fibre samples was found to decompose at around 220 C and continued up to 400 C. Slight increase of degradation temperature was observed due to the chemical treatment of fibre which indicates that major removal of lignin and hemicellulose has been achieved for CH-A-2B sample. It was observed that lignin imparts amorphous character to the polymer and its presence was confirmed by a peak at 1509 cm-1. Then, the introduction of carboxymethyl group onto the cellulose backbone was confirmed by the appearance of three new FTIR peaks at 1320, 1416, and 1590 cm-1. The presence of lignin enhanced the organo-solubility of the CMC as proven by the results of viscosity and solubility tests. In addition, XRD analyses revealed that CMC prepared from cellulose with single bleaching treatment possessed lower crystallinity compared to that of double bleaching treatment. Besides, the crystallinity index was found to increase with the increasing crystallite size due to the chemical treatment onto the fibre, however, the parameters of carboxymethylation reaction does not affect the crystallite size significantly. The ionic conductivity of CMC-based polymer electrolyte (PE) film fabricated with an addition of various lithium and ammonium salts has been indicated through EIS analysis. Besides, the presence of lignin as a function of its conductivity, was studied by comparing CH-A-1B and CH-A-2B CMC with several different carboxymethylation conditions. The highest conductivity was obtained from CH-A-1B-C:38:5 with a = 4.82 × 10-4 mS cm-1. It was found that the electrochemical properties of the polymer electrolyte were influenced by the extent of carboxymethyl substitution, degree of crystallinity and lignin content. Moreover, PE films with various NH4NO3 salt contents have been fabricated and the highest conductivity = 4.15 × 10-3 mS cm-1 was achieved by the PE where double carboxymethylation product CH-1-1B-dC:38:05 as host incorporated with 35 wt.% of NH4NO3 salt. Besides, dielectric study showed that the fabricated PE(s) obeyed non-Debye behaviour and were to be thermally activated obeying the Arrhenius behaviour
Chaos synchronization and cryptography for secure communications / Fatin Nabila Abd Latiff
No full textMany Chaos-Based Cryptographic (CBC) methods, such as chaos-based secure communication,
and chaos-based block/stream cipher, have been studied over the past decade. To the
best of our knowledge, CBC is a new field of research in two areas, such as cryptography
(computer and data security) and chaos (nonlinear dynamic system). For high security,
encryption is one of the methods used to protect data against leakage. CBC describes
chaos theory as a measure of communication techniques and computational algorithms
to perform different cryptographic tasks in a cryptographic system in specific physical
dynamic systems operating in chaotic systems. Chaos is an exciting phenomenon in
various fields, such as physics, psychology, and biology in some systems. The theory of
chaos provides the means to explain the phenomenon of chaos, control chaotic dynamic
systems, and use the properties of chaos. In particular, the characteristics of chaos, such as
robustness, merging property, sensitivity to initial conditions/parameter mismatches, the
complexity of the structure and stochastic dynamics, which maps nicely with cryptographic
requirements such as confusion, diffusion, complexity of the algorithm and deterministic
pseudo-randomness, have been shown to be appropriate for the design of data protection
means.
Besides, the probability of chaotic synchronization, where the Master System (MS)
(transmitter) drives the Slave System (SS)(receiver) via its output signal, has made it likely
that chaotic systems could be used to enforce protection in communication systems. Many
techniques, such as chaotic shift key and Chaos Masking (CM), were suggested, but many
attack methods later showed them insecurity. There are also different modifications to these methods in the literature to improve safety, but almost all suffer from the same disadvantage.
The implementation of chaotic security systems, therefore, remains a challenge. This work
introduces a Fractional-Order (FO), such as Fractional-Order Newton-Leipnik System
(FONLS) and Fractional-Order Neural Networks (FONNs), which could improve the
security of existing methods. The complexity of FO systems is due to the inclusion
and derivation of non-integer orders being addressed. If these two chaotic signals of
equal power are combined and then used to transmit message signals, it may be difficult
for intruders to use conventional attack methods because the chaotic carrier signal has
added complexity. Based on this, we analyzed various initial conditions within the same
parameters and found the best FO minimum value of FONLS.
In this thesis, the second part of chaos-based secure communication is introducing a new
encryption algorithm to improve the security of modern chaos-based communication
systems. For secure communication that is reliable, secure, and has good performance,
the focus is on developing Double Encryption System (DES). The combination of synchronization
of chaos and symmetric encryption is called DES. In this thesis, theoretically
and numerically, FONNs is formulated with multiple time delays and the stability of the
chaotic systems and their safety are analyzed
Thermochemical conversion of Chlorella spp. into biochar and its potential environmental applications / Yu Kai Ling
No full textMicroalgae are the first photosynthetic life forms of primitive earth and were able to fix atmospheric carbon dioxide (CO2) with the help of sunlight, thus creating a major step in the evolution of terrestrial plants. Microalgae are receiving increased attention recently based on their applicability in biomass production and implications on carbon capture. The microalgal biomass can be converted to several green products such as biochar and bioethanol via thermochemical conversion for environmental utilization. Biochar can be produced through thermochemical processes such as conventional pyrolysis and wet torrefaction. Thus, this study aims to study the production of microalgal biochar and its by-product using thermochemical conversion as a green technology in approach for environmental utilization. The feasibility of microalgal biochar production by conventional pyrolysis as well as simultaneous production of biochar and bioethanol using advanced wet torrefaction are investigated. Then, the characterization of microalgal biochar produced is studied for potential utilization as alternative coal fuel. Finally, the additional application of microalgal biochar on the adsorption of dye pollutants for wastewater treatment is also analyzed. Microalgae Chlorella vulgaris FSP-E with maximum biomass productivity of 0.87 g L-1 day-1 showed a biochar yield of 26.9% accomplished by conventional slow pyrolysis. C. vulgaris FSP-E biochar showed an alkaline pH value with H/C and O/C atomic ratios that are beneficial for carbon sequestration and soil application. The higher heating value of 23.42 MJ/kg of microalgal biochar also possesses its value as alternative coal. Microalgal biochar consisted of large aggregates with irregular porosity showed potential characteristics in the adsorption study. Besides, the simultaneous production of biochar and bioethanol can also be carried out through wet torrefaction. Microwave-assisted acid hydrolysis pretreatment by wet torrefaction was employed on two indigenous microalgae, Chlorella vulgaris ESP-31 and Chlorella sp. GD with different biomass compositions. The highest biochar yields of 54.5% and 74.6% can be obtained from C. vulgaris ESP-31 and Chlorella sp. GD, respectively under the wet torrefaction condition with an improvement in the properties for fuel. Wet torrefaction showed the high char yield with potential alternative fuel properties by using lower energy expense compared to the conventional slow pyrolysis. The high total reducing sugar concentration obtained in the liquid hydrolysate after the acid hydrolysis pretreatment was able to achieve the highest ethanol yield of 0.0761 g ethanol/ g microalgae. In addition, the microalgal biochar showed additional feasible adsorption performances on methylene blue and Congo red dye uptake with optimization on parameters such as adsorbent dosage, pH, initial concentration and time for future wastewater treatment utilization. Thermochemical conversion of biomass to biochar from microalgae using both conventional slow pyrolysis and wet torrefaction showed a feasible green conversion technology for environmental utilization. With the co-production of high total reducing sugar in the liquid hydrolysate that can be utilized for bioethanol production and solid biochar as another value-added product. In summary, acid hydrolysis pretreatment using wet torrefaction can be one of the environmentally sustainable conversion technologies towards the future application of renewable energy production