Nanocomposite polymer gel electrolyte based on LiBOB–cellulose acetate for lithium–oxygen battery / Siti Zafirah Zainal Abidin

This thesis focuses on the preparation and characterization of liquid electrolytes (LEs), polymer gel electrolytes (PGEs) and nanocomposite polymer gel electrolytes (NCPGEs). In this work, lithium bis(oxalato) borate (LiBOB) salt was incorporated as the source of charge carriers. LEs were first prepared by dissolving LiBOB in the solvent, γ-butyrolactone using various molar concentrations of LiBOB. The optimum conductivity (0.8 M LiBOB) of the liquid electrolyte was then gelled with different concentrations of cellulose acetate (CA) to form PGEs. The ionic conductivity of all electrolyte samples were calculated using the bulk resistance value obtained from the complex impedance plot in the frequency range between 100 Hz to 1 MHz. The ionic conductivity pattern of PGEs slightly increases at low cellulose acetate concentration and starts declining with increasing cellulose acetate content. The conductivity reaches a maximum value of 7.05 mS cm-1 for the electrolyte containing 2.4 wt.% CA at room temperature. This phenomenon is best clarified by the Breathing Polymeric Chain model. Although PGE has a high conductivity, its physical properties and dimensional stability need to be improved for practical application. Therefore, the highest conductivity of PGE was dispersed with different weight ratios of nanosized silica to obtain NCPGEs

Compressibility characteristics of Eucheuma cottonii L. powder prepared using microcrystalline cellulose and kappa-carageenan as binders

This thesis presents the study of compressibility characteristics of Eucheuma cottonii powder prepared with different binders and methods of compression. Eucheuma cottonii is red seaweed that has been cultivated in many tropical countries including Malaysia. This study consists of two different tabletting processes which were tabletting of Eucheuma cottonii with microcrystalline cellulose as a binder using direct compression method and the tabletting of Eucheuma cottonii with kappa-carrageenan as a binder using a modified wet granulation method. Seaweed has shown potential as anti-obesity, hypocholesterol, antioxidant and organ protective properties on cardiovascular health. A commercial universal testing machine with a 13-mm cylindrical stainless steel uniaxial die has been used in this study for the compression of powder. Seven different compositions of binder ranging from 0% (w/w) to 100% (w/w) with two different amounts of feed powders, 0.5g and 1.0g have been prepared. Pressures within the range of 7.5 to 74 MPa have been used during the compression process. A constant compression speed of 5 mm min-1 has been applied throughout the compression process. Effect of different amounts of feed powders and composition of binders on compression characteristics has been studied. Relationship such as volume-pressure, densitypressure, ejection force-force and tensile strength-pressure were represented in order to study the compression characteristics of Eucheuma cottonii. To understand the result further, three compression equations were used, Kawakita and Lüdde, Heckel and Walker. The best tablet formulation for both tabletting processes was determined. For tabletting of Eucheuma cottonii with microcrystalline cellulose, it has been determined that tablet with 70% microcrystalline cellulose as a binder is the best formulation whereas for the tabletting of Eucheuma cottonii with kappa-carrageenan as a binder,tablet which the composition containing 10% kappa-carrageenan as a binder has been the best formulation. Based on this approach, a better understanding of the compressibility characteristics of Eucheuma cottonii is obtained which is essential for the enhancement of the tabletting industry in Malaysia

The ambiguous brotherhood in Ursula K. Le Guin's narratives.

Ursula K. Le Guin's novels are about transcending personal boundaries to make the essential connection with another, and she shows us this attempt to form a brotherhood in two of her most famous narratives, The Left Hand of Darkness and The Dispossessed: An Ambiguous Utopia. Le Guin challenges the definitions of brotherhood and solidarity by posing the question whether social and sexual androgynies create the perfect conditions to create this brotherhood. I look into these narratives to see if masculinist individuals are able to look beyond the biological and inherent differences to transcend one’s personal boundaries and prejudices to create solidarity with those he regards as aliens. How do we define humanity when we only have bits and pieces of similarities between the different races and sexes, and is it possible to form a genuine and sincere bond for the communal progress for the different races? Le Guin implores us to look within ourselves, because we are not so different from her androgynous characters too: we also display, unconsciously, some forms of androgyny, and that we should not be so quick to dismiss her androgynous characters so quickly, and we are to look within ourselves to see that there is no exclusive definition of ‘human’ within the universes that she has created.Bachelor of Art

Effect of binder on compression characteristics of Eucheuma cottonii powder

The seaweed Eucheuma cottonii contains high levels of essential dietary minerals (Mg, Ca, K, I, Fe, Zn, Cu, Se), dietary fibre, amino acids, antioxidants and omega 3 fatty acids, which make it a good potential health supplement. Although seaweeds have been reported to provide various health benefits, their use in food is limited due to taste. The aim was to evaluate the compression characteristics of E. cottonii powder for preparation of tablets used as health supplements. The effects of various pressures applied and different levels of microcrystalline cellulose (MCC) as a binder on the compaction behaviour of E. cottonii powder were analysed using the Heckel and the Kawakita and Lüdde equations. The Heckel slope value showed that the mean yield pressure of the tablets decreased as the percentage of binder increased. Tablets with 70% MCC produced the highest tensile strength and the lowest yield pressure values, Py, which indicated that these tablets deformed plastically and were most compressible. From the Kawakita and Lüdde equation, the tablets with 70% MCC exhibited the highest value for maximum volume reduction and the lowest reciprocal value of the inclination towards volume reduction, which further validated the higher compressibility of the tablets containing this formulation. This study reports the conditions and formulation for the successful development of seaweed tablet for use as health supplement

Synergistic Effect of Partial Replacement of Carbon Black by Palm Kernel Shell Biochar in Carboxylated Nitrile Butadiene Rubber Composites

With the rapid development of the palm oil-related industry, this has resulted in the high production of palm oil waste. The increasing amount of palm oil waste has become an alarming issue in which researchers have carried out studies that this palm oil waste has the potential to be used as a biomass source. Carbon black (CB) is the most preferred reinforcing filler in the rubber industry but it has a disadvantage where CB is carcinogenic and a petroleum-based product. Hence CB is less sustainable. Palm kernel shell (PKS) derived from palm oil waste can be turned into palm kernel shell biochar (PKSBc) which can potentially be a value-added, sustainable biofiller as reinforcement in rubber composites. In this study, PKSBc is hybridized with CB (N660) at different loading ratios to be filled in carboxylated nitrile butadiene rubber (XNBR). This study aims to elucidate the effect of the varying ratios of hybrid CB/PKSBc on the rheological properties, abrasion resistance, and hardness of XNBR composites. In this study, both CB and PKSBc are incorporated into XNBR and were then cured with sulphur. The composites were prepared by using a two-roll mill. Different compositions of hybrid CB/PKSBc were incorporated. The rheological properties and physicomechanical properties, such as abrasion resistance and hardness of the vulcanizates, were investigated. Based on the results, as the loading ratio of PKSBc in hybrid CB/PKSBc increases, the cure time decreases, and the cure rate index increases. The abrasion resistance and hardness values of vulcanizates were maintained by the high loading of PKSBc which was due to the porous structure of PKSBc as shown in the morphological analysis of PKSBc. The pores of PKSBc provided mechanical interlocking to reduce volume loss and maintain the hardness of vulcanizates when subjected to force. With this, PKSBc is proven to be a semi-reinforcing filler that could not only act as a co-filler to existing commercialized CB, but PKSBc could also fully substitute CB as reinforcement in rubber, specifically XNBR as it is able to provide high abrasion resistance and hardness to the rubber composites. This would mean the performance of PKSBc is comparable with CB (N660) when it comes to maintaining the physicomechanical properties of XNBR composites in terms of abrasion resistance and hardness. Therefore, this approach of using eco-friendly filler derived from palm oil agricultural waste (PKSBc) can reduce the abundance of palm oil waste, be a sustainable alternative to act as a co-filler in hybrid CB/PKSBc to decrease the usage of CB, and helps to enhance the quality of existing rubber-based products

Commercial eye drops triggers necrotic effect in Acanthamoeba sp.

Eye infection due to microbial infection is hard to treat and painful. Two types of eye drops that are commonly used to relieve eye pain offered by pharmacists have been tested in this study namely solution A (containing tetrahydrozoline hydrochloride) and solution B (containing gentamicin and dexamethasone). The efficacy and the activities of these eye drops were tested on Acanthamoeba sp. (a clinical isolate from an Acanthamoeba keratitis patient) to study the cytotoxicity effects of the solutions on the Acanthamoeba. The Acanthamoeba were exposed to solution A and B for 24 hr and cell viability was assessed using MTT assays, morphological changes using the light microscope and through acridine orange and propidium iodide (AO/PI) staining for cytoplasmic biochemical activities. The IC50 value for Acanthamoeba cell viability was 45.1% and 20.3% for solutions A and B respectively. Morphological observation shows the inhibition of acanthapodia formation on the surface of the cells. Solution A and B-treated Acanthamoeba appeared in the red color of the cytoplasm upon staining with AO/PI indicating a necrotic mode of cell death. This is due to loss of membrane integrity of Acanthamoeba cell membrane after exposed to solution A and B at their IC50 value. It is shown that solutions A and B can cause cell death in trophozoite of Acanthamoeba cells at moderate IC50 value. Unfortunately, the necrosis mode of cell death is not a preferable type of cell death for treating Acanthamoeba infection. Therefore, it can be concluded that solutions A and B are not suitable to treat eye infected with Acanthamoeba sp. as it does not promise absolute healing as the solution concentration needed is quite high and the cell death mechanism is necrosis