13474 research outputs found
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Putative antibacterial activity of lactic acid bacteria isolated from local goat milk / Nur Shahdina Hani Mohd Zaki
No full textAntimicrobial compounds excreted by microorganisms have attracted lots of attention among researchers in the field of food microbiology as an alternative for natural preservatives and antibiotics. To compete for nutrients and space in a particular habitat, bacteria often produce natural antimicrobial compounds such as organic acids, antifungal, siderophores and bacteriocins. Hence, the aim of this study is to identify the bioactive antimicrobial compounds deriving from lactic acid bacteria (LAB) isolated from local goat milk. The screening of antimicrobial activity from 24 bacteria isolated from goat milk led to the isolation of Enterococcus faecium FGa, Enterococcus faecium RGB, Bacillus cereus FG1 and Serratia marcescens FG3. These strains show good inhibition zones against varying types of foodborne pathogens such as Staphylococcus aureus SA7001, Shigella boydii SB1003, Shigella dysenteriae SD1007 and Salmonella typhimurium SM4001. The antimicrobial substances in cell-free culture supernatant of all four isolates were stable against S. aureus at different temperatures, pH and also when exposed to proteolytic enzymes except pepsin for E. faecium FGa and E. faecium RGB. The mode of action for isolates was determined as bactericidal where they lysed the cells of S. aureus which induced the unbalanced growth of its cell cycle. Since LAB are our main aim, both E. faecium FGa and RGB have undergone further safety evaluation. Both strains show good probiotic properties since they can survive well under conditions simulating the human GI tract and do not show any potential virulence characteristics. Enterocin A has been detected through PCR amplification in one of our E. faecium strains which is E. faecium FGa. This indicates it as one of the possible compounds that is responsible for antimicrobial activity. E. faecium FGa has also undergone Q-TOF LC/MS analysis and several metabolites that may also contribute to antimicrobial activity have been detected which are netilmicin, maleic acid and 2-furonic acid. Hence, E. faecium FGa can be used as a potential bio-preservative or protective culture in our food industry
A multimodal analysis of selected literary elements in award-winning Malaysian picturebooks / S. Komathy Senathy Rajah
No full textPicturebooks are a suitable medium for embracing multimodal literacy and literature as they characterise a unique visual and literacy art form that keeps young learners engaged at all times (Arizpe & Styles, 2016). This study investigates how the visual and textual meaning making systems work individually and also cohesively to develop a selection of four literary elements in Malaysian picturebooks. The theoretical frameworks for this study are established on the works of Painter et al’s (2013) Multimodal Discourse Framework which in return is based on the frameworks of Systemic Functional Linguistics (Halliday, 1994); Grammar of Visual Design (Kress & van Leeuwen, 1996, 2006); and Appraisal Framework (Martin & White, 2005). Six Noma-Concours award-winning Malaysian picturebooks were analysed and interviews with the writer-illustrators for triangulation were conducted.
The visual analysis of the literary element ‘character’ indicates that conceptual images are used to introduce the main characters and highlight their physical attributes, while character qualities are inferred visually by looking at the characters’ actions. Semiotic resources like size, position and proximity are used to identify the main characters and the type of relationships that they form. Additionally, the writer-illustrator interviewed in the study have also shed light on how to identify the main characters. The visual analysis of ‘setting’ indicates that maximum commitment of circumstantiation is established through panoramic views. Also, the analysis of ‘point of view’ reveals that the contact option is seen mainly in picturebooks written from the first-person perspective, while resources like facial expressions and colours realise the literary iv
element ‘mood ‘in most picturebooks. This study also investigates how textual meaning potentials are composed to represent the literary elements. The textual analysis of character attribution shows that descriptive intensive attributes are predominantly used while the analysis of evaluative language provides information about character qualities. Character identification helps to verify and track the characters and indirectly, establish the weight of their roles while the findings on character relationship reveals the wide interpersonal distance between them. Successively, the analysis of setting reveals that the backdrop setting is kept simple and straightforward while the analysis of point of view reveals the predominant use of limited omniscient perspective. The textual analysis of mood shows that verbal affect is mainly realised through inscribed instances. Finally, the findings for intermodal cohesion are revealed on a picturebook-by-picturebook basis. Overall, the textual analysis shows a lack of detailed external characterisation, setting and mood elements but the visual depiction of the three literary elements addresses these shortcomings effectively. The intermodal cohesion results clearly show that literary elements are represented in both semiotic modes and meanings multiplies when they are understood simultaneously. This concurs with Moya’s (2014) postulation that “picture adds specificity to the verbal text as it provides an instantiation of the text and attaches additional meaning” (p.71).
In short, this study enhances knowledge specifically in the areas of multimodality as the findings from this study are used to develop a ‘Visual Metalanguage Checklist’ that is sufficient for a theoretical analysis of literary elements in picturebooks
Surface functionalization of magnetite nanoparticles with natural and multipotent antioxidants as potential nanoantioxidants and antimicrobial agents / Syed Tawab Shah
No full textNanoparticles of Fe3O4 with enhanced hydrophilic/lipophilic properties were synthesized using a co-precipitation approach of Fe2+ and Fe3+ ions in a basified aqueous solution followed by a surface functionalization. Two surfacing strategies (in-situ and post-synthesis methods) were used to coat nanoparticles with natural antioxidants and synthetic multipotent antioxidants (MPAO). MPAO were synthesized and characterized by NMR. The functionalized nanoparticles (IONP@AOx) were characterized by FTIR, XRD, Raman, HRTEM, FESEM, VSM and EDX. IONP@A have average particles size 6-8 nm for in-situ synthesis, which are ultra-small particles as compared to unfunctionalized magnetite (IONP) and post functionalized magnetite with average size of 10 and 11 nm respectively. The nanoparticles also showed high saturation magnetization of about 45−59 emu/g. Prior to commencement of experimental lab work, Prediction Activity Spectra of Substances (PASS) software was used to predict the biological activities of antioxidants and it is found that experimental antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay are in good agreement with the simulated results. Furthermore, the half maximal inhibitory concentration (IC50) values of DPPH antioxidant assay revealed a 2–4 fold decrease as compared to unfunctionalized IONP. The functionalization has enhanced the free radical scavenging properties of IONPs up two to four times. In addition to antioxidant activity, functionalized IONP proved outstanding antimicrobial activity while testing on different bacterial and fungal strains. The advantage of the developed nanoantioxidants is that (because of their high hydrophilicity/lipophilicity) they could interact with biological species such as enzymes, proteins, amino acids and DNA. The results reveal that the synthesized nanoparticles can be successfully used for the development of biomedicines which can be subsequently applied as antioxidant, anti-inflammatory, antibacterial and anticancer agent
Development of all-fiber pulsed lasers using bismuth- and thulium- doped fiber saturable absorber / Pei Zhang
No full textDue to the abundant advantages of low lasing threshold, simple configuration, high efficiency, long-time stability and low cost, all-fiber pulsed fiber lasers have attracted plentiful attentions in various applications such as materials processing, fast diagnosis, nonlinear optics, biomedicine, communication etc. Compared with other saturable absorber (SA), using the doped fiber saturable absorber (DFSA) is an effective and efficient method to realize all-fiber pulsed lasers. In this thesis, bismuth-doped fiber (BDF) and thulium-doped fiber (TDF) with different lengths are used to construct DFSAs. All DFSAs are characterized to ensure the linear and nonlinear absorption before being inserted into the typical ring cavity of fiber lasers. Q-switching, mode-locking and other operation modes are experimentally demonstrated in the erbium-doped fiber laser (EDFL) and neodymium-doped fiber laser (NDFL). The formation mechanism and performance characteristics of different pulses are systematically studied and analyzed in the all-fiber pulsed lasers with different configurations. Firstly, the 15cm and 30 cm Bismuth-DFSAs have been used to achieve all-fiber Q-switched EDFLs. The pulse width of Q-switching pulses by using 30 cm bismuth-DFSA is 1.18 μs, which is shorter than 3.66 μs by using 15 cm bismuth-DFSA. The 15 cm bismuth-DFSA is applied to successfully generate triple-wavelength vector dark solitons in self-starting mode-locking EDFL. The operating wavelengths are located at 1595 nm, 1598 nm, and 1602 nm simultaneously and the repetition rate is 1.89 MHz. Secondly, the 18 cm thulium-DFSA is used to generate Q-switching pulses in single and dual-wavelength Q-switched EDFL. The operating wavelengths of dual-wavelength operation are located at 1532.6 nm and 1557nm. By simply adjusting the polarization, the dual-wavelength operation can be switched into two single-wavelength operations at 1532 nm and 1558 nm, respectively. The single-wavelength all-fiber laser at 1532nm have better performance than that at 1558 nm, such as shorter pulse width, higher repetition rate and higher SNR. The 12 cm thulium-DFSA is used to generate ultrashort pulses in mode-locking EDFL at the wavelength of 1568.2 nm. The pulse width of mode-locking pulses is 2.27 ps with a repetition rate of 0.99 MHz and a SNR of 63 dB. Thirdly, Q-switching, Q-switched mode-locking and mode-locking operation modes are sequentially realized in a self-starting EDFL by using 12 cm thulium-DFSA. In addition, the 30 cm bismuth-DFSA is used to realize a dual-wavelength NDFL at 1080.8 nm and 1090.2 nm as a filter. A pure sinusoidal continuous wave is generated with the frequency of 9.1 MHz. Besides the sound stability of lasers, DFSAs have been proved to have higher damage threshold than other SAs, and furthermore possesses the ability of generating ultrashort pulses in an all-fiber laser for the first time
Pembangunan modul pedagogi surah al-Fatihah dan tiga qul berasaskan teknologi untuk pelajar pekak di kolej vokasional / Muhammad Sayuti Sabdan
No full textPendidikan Islam terutamanya pendidikan al-Quran merupakan pendidikan agama yang perlu / wajib diajari dan dipelajari oleh setiap insan beragama Islam. Berdasarkan pemerhatian dalam kajian literatur, penyelidik mendapati bahawa terdapat isu utama menjadi permasalahan yang dihadapi oleh pelajar pekak di Kolej Vokasional terutamanya melibatkan modul pengajaran dan pembelajaran al-Quran. Oleh itu, tujuan kajian ini dijalankan adalah untuk membangunkan modul pedagogi surah al-Fatihah dan Tiga Qul berasaskan teknologi untuk pelajar pekak di Kolej Vokasional. Oleh itu, kajian ini dijalankan melibatkan tiga fasa iaitu fasa analisis keperluan, reka bentuk dan pembangunan serta analisis penilaian keberkesanan. Data bagi fasa pertama adalah analisis keperluan telah dilaksanakan melalui temu bual separa berstruktur terhadap 10 orang guru al-Quran untuk pelajar pekak. Seterusnya ialah peringkat fasa kedua iaitu reka bentuk dan pembangunan modul. Data pada peringkat reka bentuk diperoleh melalui teknik Fuzzy Delphi terhadap 19 orang pakar pendidikan Islam, pengajian al-Quran, pendidikan khas masalah pendengaran, teknologi pendidikan, serta teknologi komunikasi dan maklumat. Data dianalisis berdasarkan respons pakar terhadap borang soal selidik iaitu merujuk kepada lima skala Likert Linguistik Fuzzy. Seterusnya nilai ‘d’ dihitung. Ini adalah bertujuan untuk mendapatkan konsensus daripada panel pakar terhadap semua item yang terdapat dalam borang soal selidik. Manakala pada peringkat pembangunan pula adalah melibatkan pemurnian rancangan pengajaran dan pembelajaran serta laman web terhadap reka bentuk modul, isi kandungan modul, aktiviti pengajaran dan pembelajaran, dan pelaksanaan penilaian modul oleh empat orang pakar. Pada fasa yang terakhir iaitu ketiga, praujian dan pascaujian dijalankan ke atas 15 orang pelajar pekak di Kolej Vokasional. Dapatan kajian fasa pertama menunjukkan bahawa terdapat keperluan modul pedagogi surah al-Fatihah dan Tiga Qul berasaskan teknologi untuk pelajar pekak di Kolej Vokasional. Dapatan analisis temu bual separa berstruktur menunjukkan bahawa modul pedagogi al-Quran untuk pelajar pekak masih kurang dilaksanakan secara tersusun. Oleh itu, dapatan kajian menunjukkan menjadi satu keperluan untuk membangunkan modul pedagogi al-Quran untuk pelajar pekak khususnya di Kolej Vokasional. Seterusnya dapatan kajian bagi fasa reka bentuk kajian menunjukkan kesemua panel pakar telah mencapai konsesus nilai ‘d’ ≤ 0.2 iaitu dengan peratus melebihi 75% berdasarkan item-item yang sesuai dalam modul pedagogi tersebut. Manakala dari sudut pembangunan modul pedagogi surah al-Fatihah dan Tiga Qul perlu dilakukan beberapa penambahbaikan seperti reka bentuk modul tersebut. Fasa penilaian pula iaitu ujian t berpasangan dilaksanakan menerusi praujian dan pascaujian. Data menunjukkan pencapaian dari sudut kefahaman yang signifikan dengan nilai p adalah .00 iaitu kurang daripada 0.5 (p< .05). Oleh itu, modul pedagogi surah al-Fatihah dan Tiga Qul berasaskan teknologi untuk pelajar pekak di Kolej Vokasional adalah sesuai diaplikasikan pada peringkat Kementerian Pendidikan Malaysia, guru / pensyarah dan pelajar pekak dalam pendidikan Islam pengajian al-Quran
Effect of sintering additives on the densification and mechanical properties of alumina toughened zirconia ceramic composite / Mohamed Kamaleldin Gaffar Abbas
No full textIn this research, the influence of transition metal oxide and stainless steel on the sintering behavior of alumina toughened zirconia (ATZ: 20 wt% Al2O3 + 80% Y-TZP) was studied. In Phase 1, selective dopants i.e. 0.2 wt% stainless steel, 0.5 wt% manganese oxide and 0.2 wt% copper oxide were doped with the ATZ. The prepared ceramic composites were subjected to conventional sintering (CS) at 1250 °C, 1350 °C and 1500 °C, using different holding times of 1, 12, 120 min. The tetragonal phase stability, microstructural evolution, relative density, Vickers hardness and the fracture toughness of the samples were assessed. In Phase 2, the sintering behaviour of these ATZs was compared with that obtained by using microwave (MW) sintering at the same temperature regimes with a holding time of 5 min. The results revealed that all the dopants were beneficial in aiding the densification of ATZ, particularly at low temperatures and short holding times. In particular, the addition of copper oxide (CuO) was found to be most effective in enhancing the properties of ATZ when sintered at 1250 °C and 1350 °C using a short holding time. The results indicated that sintering at 1500 °C was unnecessary for the copper-doped ATZ to attain a maximum relative density of > 98%, Vickers hardness of > 12 GPa and fracture toughness of > 5 MPam1/2. In contrast, the undoped ATZ required a longer holding time and high sintering temperature to achieve similar results as the doped samples, but this scenario could be overcome through microwave sintering. Phase 3 of this research focused on the effect of doping various amounts of CuO (0.05 wt% to 1 wt%) on the densification behaviour of ATZ using both the CS and MW methods. It was found that the tetragonal phase stability was not disrupted for addition up to 0.2 wt% CuO. However, a spontaneous t to m phase transformation upon cooling from sintering was inevitable for the 0.5 wt% and 1 wt% CuO doping, with amounts exceeding 30% being measured in these samples. The m phase development in the ATZ matrix was accompanied by low density and poor mechanical properties. The addition of 0.2 wt% CuO was found to be optimum amount for doping and the sintered composite exhibited overall best performance i.e. a relative density of about 92% was obtained at 1250 C, about 97% dense at 1350 C and above 99% dense at 1450-1500 C. This was also accompanied by high Vickers hardness of 12.7 GPa and fracture toughness of 6.94 MPam1/2 when sintered at 1450 °C/12 min. The results also showed that in general the Vickers hardness increased linearly with increasing relative density regardless of sintering methods. Finally, in Phase 4, the effect of low-temperature degradation (LTD) or hydrothermal ageing on the undoped ATZ and 0.2 wt% CuO-doped ATZ was investigated by exposing the samples to autoclave conditions containing superheated steam at 180 ℃/10 bar for periods up to 100 h. It was found that the tetragonal phase stability was disrupted for samples sintered above 1400 C and that the CuO dopant was not effective in suppressing the ageing-induced phase transformation. A critical tetragonal grain size limit of about 0.23 m was determined for the present ATZ, above which resulted in LTD
Representation of the Rohingya crisis in The Daily Star / Tanjina Akter Ety
No full textThis study investigates the representation of the Rohingya crisis in the media. The corpus of 223 news articles has been collected from Bangladeshi newspaper, The Daily Star from November 2017 to November 2019, after the repatriation deal between Bangladesh and Myanmar on 23 November 2017. To explore how The Daily Star used quoted voices to represent the Rohingya crisis, Halliday's transitivity process was used as an analytical tool from his Systemic Functional Grammar (SFG) method. The UN, NGO, Government and Other government voices state that the human rights violation by Myanmar created the Rohingya crisis. The humanitarian UN and NGO voices reflect the Rohingya victimization and also represent them as a vulnerable group in both Bangladesh and Myanmar. The crisis is also reflected as a humanitarian issue in Bangladesh through Government, UN and Other government voices. Meanwhile, the Government voices reflect Myanmar as obliged to make a successful and voluntary return of the Rohingya in Rakhine and Rohingya as threat, representing the crisis as a problem in Bangladesh and the voluntary return of the Rohingya to Myanmar is the onl
Real-time control and power management for interconnected microgrids with self-healing capability / Shameem Ahmad
No full textCompelled by economic and environmental factors, microgrid (MG) has emerged as pioneer small-scale power generation system. However, it is necessary to ensure reliable and resilient operation of the MGs to avoid power failure incidents, which is a challenging task. Connecting multiple MGs to form interconnected MGs can improve power distribution systems resiliency and reliability. However, there are challenges while interconnecting multiple MGs, like possibility of power imbalance between distributed generators (DGs) capacity and load demand, complexity in modeling MGs controllers, and uncertainty of balanced power sharing among multiple MGs. To address all these issues, in this thesis, real-time control and power management systems (PMSs) for two interconnected MGs are developed. Voltage source inverters (VSIs) are important elements of grid-connected single MG to integrate photovoltaic system with utility grid which require fast response, stable and robust controllers for efficient operation. In this thesis, three power control methods are modeled for PV VSI among which the first two are fuzzy logic controller (FLC) and proportional integral (PI) controller based direct power control (DPC) methods, while, the remainder is dq current control theory (CCT) based power control method without using phase-locked-loop (PLL) and Park transformation. In addition, to ensure balanced power flow from different sources to the loads for acquiring better power quality and stable operation of MG, real-time PMSs are developed for both grid-connected and islanded modes of MG’s operation by taking into account the maximum utilization of renewable energy sources, energy storage systems and prioritization of critical loads together. Further, to improve the reliability of power distribution system, intelligent interconnection methods (IIM) for interconnecting two MGs with self-healing and interconnection capability are proposed by considering the power imbalance between DGs generation capacity and load demands of all the MGs. Moreover, to ensure balanced power sharing among multiple MGs during self-healing and interconnected modes of operation, PMSs for individual MGs are developed. Finally, to ensure flexible and smooth transition of multiple MGs among various operation modes like grid-connected, islanded, interconnected and self-healing, a multi-layer control strategy (MLCS) is formed. The real-time simulations are carried out using real-time digital simulator (RTDS) to validate the performance of the proposed power controllers, PMS, IIMs, and MLCS. From the simulation results, it has been observed that the proposed power controllers have better reference power tracking time ranging from (0.03 s – 0.11 s) along with reduction in output power ripples and current total harmonic distortion (THD) which are ranged from 1.6 % to 2.492 %. Further, the results show that through the implementation of the proposed PMS, maximum use of renewable energy sources and energy storage systems are ensured in MG by maintaining balance between supply-demand. The results also demonstrate that the developed IIMs can interconnect two MGs successfully to operate in self-healing and interconnected modes while the PMSs ensure balanced power sharing among the MGs. The final simulation results confirmed that the two MGs can operate flexibly and transit from one operating mode to another smoothly by employing the proposed MLCS
Keywords in a longitudinal corpus of narrative writings by Malaysian Secondary School students / Chen Tien Mie
No full textA keyword in a corpus study refers to a word that is significantly more frequent in a particular corpus than the other (Hunston, 2002, p. 68). Keywords are also indicators of the “aboutness” of a particular text (Baker, 2004; Hyland, 2008; Bondi & Scott, 2010). In relation to second language development, translanguaging is defined as the “flexible use of linguistic resources by bilinguals to make sense of their worlds” (Garcia, 2014, p. 3). This present study focuses on the changing use of keywords from a translanguaging perspective over a five-month period across three points in time in a longitudinal corpus of 129 narrative essays of 43 bilingual and multilingual students. It was observed that the relative frequencies of keywords were not consistent over time. For example, the keywords, scared and excited showed a decrease in relative frequency over time while December, sibling, practise, hostel, scold and highland showed an increase. The keywords, Malaysia, colour, karaoke, favourite, celebrate and amazing first showed increase in relative frequency before decreasing over time. Changes were observed in the use of some keywords over a five-month period. The keyword, colour was initially used as a noun. Over time, colour as a noun was still used but in Time 3, it was used as an adjective. The keywords, celebrate and practise, initially used as verbs, were used as nouns in Time 3. Furthermore, a pattern of fluctuation was observed where a range of adverbs were seen to co-occur with three keyword adjectives, scared, excited, and amazing over time. In Time 3 particularly, only adverbs, extremely and most, and super and extra, have co-occurred with scared and excited respectively. This suggests that the development of learner language is an unpredictable and fluctuating process that is never linear (Larsen-Freeman, 2006). From a translanguaging perspective, it is observed that the students express meaning through their written linguistic variations that co-occurred with keywords. This is seen through their spelling and sentence variations while engaging in Bahasa Malaysia through words of peluang, ayah, keluarga and marah. These linguistic variations should not be viewed as errors (Canagarajah, 2011) but as a process of meaning making and a learning strategy for bilingual and multilingual to fully deploy their linguistic repertoires freely without regard for named languages (Otheguy, Garcia & Reid, 2015; Velasco & Garcia, 2014; Li & Ho, 2018)
China’s high-quality economic development: The industrial structure and upgrading approach / Tao Miaomiao
No full textChina aims to promote its economy into a new stage of high-quality development by limiting the mismatches between the economic structure, the polarisation of social income and environmental deterioration that has restricted the sustainable development of China's economy. Industrial structure transformation and upgrading are crucial for China to achieve high-quality economic development in the coming era. This study has sought to measure the performance of China's high-quality economic development from a temporal-spatial perspective. This study used panel data from 30 of China's provinces and the ''Five new development concepts'' to assess China's high-quality development to model the effect of the industrial structure and upgrading on China’s high-quality economic development. The five subsystems comprise; innovative development, coordinative development, green development, open development and sharing development, which has allowed this study to construct a comprehensive index determined by a combined weighting determination procedure. The index construction was followed by analysing China's high-quality economic development based on temporal-spatial perspectives. This study applied the cluster analysis method to classify China's 30 provinces into 12 groups based on the performance of high-quality economic development using absolute, relative, and fluctuating scores. This study used Moran's Index and Moran scatterplot to analyse the spatial distribution characteristics of highquality economic development and the Geo-detector method to identify the heterogeneity of high-quality economic development among China's three economic zones. In contrast, the Cloud model has allowed mapping of China's industrial structure rationalisation and upgrading distribution characteristics and its composite systems to measure China's industrial structure transformation and upgrading. The impacts of industrial structure upgrading, rationalisation, and composite systems on high-quality economic development were assessed by adopting the Spatial Durbin Model from national and regional perspectives. China's economy has gradually pursued a high-quality development pattern with an annual growth rate of 0.459%. However, the results showed that China's regional economic development had not followed a high-quality development path, with an average value of 0.219 indicating regional imbalances. High-quality economic development was low and regional differences were significant. Specifically, the high-quality economic development level in the central and western provinces was relatively backward compared to Eastern China. In the meantime, the spatial autocorrelation of the high-quality economic development index decreased yearly. Besides, this study indicated that the eastern region's industrial structure transformation and upgrading distribution characteristics were better than the central and western areas. Finally, the industrial structure upgrading, rationalisation, and composite systems positively affected high-quality economic development nationally and for the eastern and central regions but negatively affected the western region. This study has provided fresh evidence concerning the role of China's industrial structure transformation and its upgrading toward high-quality economic development, fulfilling a research gap. The
study's results can aid China in solving its development dilemma, thereby sustaining inclusive economic development