19672 research outputs found
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Investigation of the potential induced degradation of on-site aged polycrystalline PV modules operating in Malaysia
No full textOn-site investigation of PID behavior of PV module has been carried out under typical Malaysian climate. A quantitative degradation measurement process of PV module through EL imaging has been introduced. PID has been observed only for the negative voltage stress in this p-type polycrystalline Si PV module. The negative end PV module degrades 42% due to 9 years field aging under a negative voltage stress from the 240 V string size. While positive end PV module is degraded near about 17% over the same period due to normal field aging. Shunt resistance of negative-end module has been found 75% lower than that of the positive-end module. Module crack propagation is found to be accelerated due to onsite cyclic high voltage stress. PID at higher string size has been estimated from the leakage current of brand new same PV module. The estimated PID of PV module under 600 V stress is 72.84%
Influence of growth duration to the Zinc Oxide (ZnO) nanorods on single-mode silica fiber
No full textSynthesizing Zinc Oxide (ZnO) nanorods by varying the growth duration will give effect to the morphology of ZnO nanorods which were grown by using microwave assisted hydrothermal method. The effect of different growth duration from 4 to 10 hours is investigated on the surface of bare silica optical fiber. The buffer coating of a silica fiber is stripped off for 5 cm to expose the area for the growth of ZnO nanorods. The ZnO nanorods were grown on the fiber by dipping the fiber into the prepared growth solution in a 90C microwave assisted hydrothermal synthesised. The physical characterization through field emission scanning electron microscopy (FESEM) results show the diameter of ZnO nanorods is about 75.0 - 93.8 nm and the length of ZnO nanorods ranges from 666.2 nm to 978.6 nm according to their growth duration. The uniform growth of 43.33 nanorods/(µm)2 reveals that the 10 hours of growth duration performs the highest density growth of ZnO nanorods. The amplified spontaneous emission (ASE) peaking at 1550 nm is used to investigate the effect on the light intensity in the optical fiber with coated and uncoated ZnO for optical characterization. The ASE spectrum shows that the light intensity decreases with the growth durations due to the light scattering effect
Generalized Φ-dichotomous linear part for a class of generalized differential equations
No full textA dichotomy: ordinary or exponential, is a category of conditional stability. In this disquisition, we deal with nonlinear fractional differential equations (NFDE) involving generalized Φ-exponential and Φ-ordinary dichotomous (in the sense of fractional calculus) linear part in a Banach space. By employing of the Banach fixed point principle, the satisfactory conditions are located for the existence of Φ-bounded outcomes of these equations in the real case
Image steganography in spatial domain: A survey
No full textThis paper presents a literature review of image steganography techniques in the spatial domain for last 5 years. The research community has already done lots of noteworthy research in image steganography. Even though it is interesting to highlight that the existing embedding techniques may not be perfect, the objective of this paper is to provide a comprehensive survey and to highlight the pros and cons of existing up-to-date techniques for researchers that are involved in the designing of image steganographic system. In this article, the general structure of the steganographic system and classifications of image steganographic techniques with its properties in spatial domain are exploited. Furthermore, different performance matrices and steganalysis detection attacks are also discussed. The paper concludes with recommendations and good practices drawn from the reviewed techniques
Recursive Information Hiding Scheme Through LSB, PVD Shift, and MPE
No full textIn this study, a new data embedding method is proposed to enhance the embedding payload by combining irreversible and reversible methods. The proposed method is based on pixel value difference (PVD), least significant bit (LSB) substitution, PVD shift, and modification of prediction error (MPE). A pixel block (2 × 1) is initially classified into lower and higher texture areas, and secret data are embedded through LSB and PVD, respectively. The pixel block is then recursively employed through PVD shift and MPE embedding methods to increase the payload. Experimental results demonstrate that the proposed method significantly increases the embedding capacity to 53,917 bits and maintains the visual image quality to 38 dB. The proposed method also provides robustness against regular/singular steganalysis
Weight loss effect and potentiodynamic polarization response of 1-butyl-3-methylimidazolium chloride ionic liquid in highly acidic medium
No full textIonic liquids are increasingly being used as corrosion inhibitors when oil and gas industries started to give focus on sustainability and green impact in their operations. In this study, 1-butyl-3-methylimidazolium chloride ionic liquid in 2M HCl medium has been investigated on mild steel, stainless steel and aluminium bars by using weight loss technique and potentiodynamic polarization measurement. Results showed that 1-butyl-3-methylimidazolium chloride is able to reduce the weight loss of aluminium metal under acidic corrosive surrounding up to 11% compared to that of without the presence of 1-butyl-3-methylimidazolium chloride. Based on potentiodynamic polarization response, percentage of corrosion inhibition efficiency is found to be up to 99.3%. In summary, 1-butyl-3-methylimidazolium chloride is highly potential to act as an anti-corrosion agent, even in a very low concentration
The historicization of nostalgia, locality and quotidianity: on the changes in Lim Kim Chern’s gastronomic writing
No full textThis article seeks to shed light on Lim Kim Chern’s gastronomic writing, by ensconcing this individual case in the context of Modern Chinese Prose as an enduring literary tradition, in order to elicit the attribute of locality with diasporic discourse in quotidian life, that distinguishes it as part of a work in Malaysian Chinese Literature than the others. We will further this quest, by comparing the gastronomic writing of Lim before and after the changes in his literary pursuit in gastronomic writing, namely, by the comparison of the literary hierarchy of high-brow literature and the sub-genre of literature that post-positions the literariness, in order to examine whether or not it is a revelation, or even a harbinger of the fate of Malaysian Chinese Literature being minor literature
Simple method for functionalization of silica with alkyl silane and organic ligands
No full text3–(chloropropyl)triethoxysilane (CPTES) with imidazole and sodium silicate from rice husk ash (RHA) successfully reacted within a short time in one–pot synthesis in purely homogenous method. A similar procedure was used for the immobilization of melamine and saccharine to demonstrate a generally applicable method. No reflux was needed, and a green solvent was used as the reaction medium. The surface areas of the prepared materials were very high compared with the materials which have similar structure prepared by the traditional method. The TGA/DTA confirmed that all the materials were highly stable. The FT-IR shows that all expected the functional groups were present. The HRTEM showed that the materials had ordered mesoporous straight-channels which were like the MCM-41. The synthesis procedure is simple, repeatable with different organic ligands and does not require toxic solvents or multiple steps with high products yield
The views and experiences of Malaysian primary care doctors in managing patients with chronic low back pain: A qualitative study
No full textBackground: Chronic low back pain (CLBP) is a common and often difficult to treat condition in the primary care setting. Research involving in-depth exploration on the views and experiences faced by primary care doctors in managing patients with CLBP in Malaysia is limited. Objective: To explore the primary care practitioners’ views and experiences in managing patients with CLBP. Study design: A qualitative approach was employed using focus group discussions (FGD) at an academic primary care clinic in Kuala Lumpur, Malaysia. Twenty-three primary care doctors were purposively selected. Data were collected through audio-recorded interviews, which were transcribed verbatim and checked for accuracy. Data saturation was reached by the third FGD. An additional FGD was included to ensure completeness. A thematic approach using the one sheet of paper (OSOP) method was used to analyse the data. Results: Participants view managing patients with CLBP as challenging. This is mainly due to the difficulty in balancing the doctors’ expectations with the patients’ perceived expectations during consultation. Barriers identified include lack of awareness and conflicting views regarding the usefulness of the local clinical practice guideline (CPG) in clinical practice. Other barriers include time constraints and perceived lack of support from multidisciplinary teams in managing these patients. Conclusion: Managing patients with CLBP is still a challenge for Malaysian primary care doctors. Any intervention should target identified barriers to improve the management of patients with CLBP
Cost Effectiveness of a Platelet-rich Plasma Preparation Technique for Clinical Use
No full textINTRODUCTION: Despite limited clinical evidence, platelet-rich plasma (PRP) is currently used for the treatment of various soft tissue injuries, but optimal use of PRP has yet to be determined. In many instances, PRP is prepared using commercial devices that lack standardized preparation techniques and consistent quality of the PRP produced. OBJECTIVE: The aim of this study is to explore a simple, easy, economical method of PRP preparation that is practical for clinical use. MATERIALS AND METHODS: This cross-sectional study was conducted at the Sports Medicine Clinic at the University of Malaya Medical Centre, Malaysia. Participants were healthy postgraduate students and staff at the Sports Medicine Department. The PRP was prepared using a single centrifugation technique. Leukocyte and platelet levels were compared with that of a whole blood baseline and a commercial preparation kit. RESULTS: The PRP produced using this technique contained significantly higher mean platelet (1725.0 vs. 273.9 x 109/L) and leukocyte (33.6 vs. 7.7 x 109/L) levels compared with whole blood. There was no significant difference in the mean platelet and leukocyte levels between the PRP produced in this study and by a commercial PRP system. CONCLUSIONS: A single-centrifugation protocol using readily available materials in a typical clinical setting could produce PRP of comparable quality to those of a commercial PRP production system