13474 research outputs found
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Exploitation of Plasmon resonance phenomenon for the improvement of direct absorption solar collector performance / Abdul Rahman Mallah
No full textDirect absorption solar collectors (DASCs) are distinguished from other solar collectors by the volumetric absorption process, where the working fluid directly absorbs solar radiation. Studies have shown that DASCs can increase energy conversion efficiency by ~10% compared with conventional solar collectors. With advances in the development of nanotechnology, the concept of volumetric absorption is now feasible. Advances in nanotechnology accompanied by phenomenal discoveries at the nanoscale have made it possible to produce plasmonic materials. Plasmonic materials exhibit distinct optical characteristics under specific conditions. The free-electron cloud of metallic nanoparticles oscillates harmonically with the incident radiation. At a particular wavelength, resonance occurs between the collective oscillations of electrons and the incident electromagnetic waves, which intensifies the photo-thermal energy conversion at the resonance conditions. This phenomenon is known as localized surface plasmon resonance (LSPR), which gives exceptional absorption efficiency for plasmonic nanoparticles at the resonance wavelength. There is great potential to use plasmonic nanoparticles in the direct absorption solar collectors. This study provides insight into the LSPR phenomenon of silver nanostructures and an innovative technique is proposed to exploit their capabilities to boost the efficiency of volumetric solar collectors. Silver nanoparticles exhibit LSPR with high intensity, which can be adjusted within a broad spectral band of 300–1,200 nm by tailoring the shape, size, and aspect ratio of the nanoparticles. In this study, the optical characteristics of various silver nano-morphologies were investigated to formulate blended nanofluids that can absorb solar irradiation within a broad spectral range. The finite element method has been implemented to determine the absorption efficiency of different silver nano-morphologies like silver nanospheres, nanorods, nanoplates and core/shell silver/silica nanocomposites. Also, the effects of the nanoparticles’ size and aspect ratio were extensively studied. The results were used to formulate a high-efficiency blended nanofluid with a very low volume fraction of silver nanoparticles. The simulation results revealed that the different silver nano-morphologies absorb efficiently at different solar spectrum bands. Silver nanospheres and nanoprisms with fine-tuned sizes and aspect ratios of 3–9 were synthesized and characterized. An innovative test section was built to validate the performance of different silver nano-morphologies under simulated solar irradiation. The test section allows the irradiance bands that have not been absorbed by the nanoparticles to escape from the collector instead of being absorbed or reflected by the bottom surface, unlike the test sections in conventional experiments. Hence, the photo-thermal conversion efficiency of nanofluids based on individual silver nano-morphologies can be accurately obtained. Five nanofluids were tested under three irradiation densities equivalent to 1, 1.5 and 2 suns. Three concentrations of each nanofluid were prepared and tested at varied Reynolds numbers ranging from around 150 to 750. The main contribution of this work is the formulation of blended nanofluids containing different silver nano-morphologies to efficiently absorb the broadband solar spectrum. The experimental results revealed the promising performance of the blended nanofluids, where the efficiency of the direct absorption solar collector exceeds 70% at a solar radiation concentrating factor of ~2 and a total nanoparticle concentration of 0.001 wt%. The interesting aspect of the blended nanofluids formulated in this study is the remarkable low volume fraction of the nanoparticles, which reduces settlement and agglomeration ratio. Consequently, a higher solar concentration ratio can be harnessed by using the blended plasmonic nanofluids with a relatively low loading of nanoparticles
Millennium manuscripts of hadith: Scholarship and methodology an analytical comparative study / Ibrahim Najm Abdulrahman
No full textWe have quite a number of millennium manuscripts of Hadith, some of which are considered original. However, a group of researchers questioned the authenticity of these manuscripts, while others claimed them unreliable since they were not based on a reliable methodology in dhabt (i.e., accuracy) and documentation. To answer these ambiguities, this study examined the methodology of Muhaditheen (Hadith narrators) in accuracy, verification and rectification in their early millennium manuscripts. The study followed inductive and analytical comparative method. It gathered opinions of Hadith narrators concerning the methodology of the manuscript accuracy and precision. Then, it searched for millennium manuscripts and managed to collect (149) manuscripts in Hadith. A number of (47) manuscripts were chosen to be analyzed, criticized and compared to set its methodology. Also, a group of principles and basics on which Hadith narrators of millennium manuscripts based their work were pointed out and compared with those stated in books of Hadith. This is to show the strong correlation between manuscript scholarship and Hadith terminology. This study concluded a number of significant additions in millennium manuscripts that were not mentioned by Hadith scholars in their books. Also, it stated the additions of Hadith scholars among themselves, their diversity and preferences in issues related to the accuracy and rectification of the manuscript by comparing between Hadith scholars in books of Hadith. It also showed that Hadith narrators used abbreviations and symbols in their manuscripts since early times of compilation; the oldest found in the 3rd Hijri century. As well as, the study gathered data of millennium manuscripts of Hadith found in public and private libraries for inspection and precise description. It was able to pin out some mistakes made by editors and indexers in describing these millennium manuscripts. The study described (149) millennium manuscript in Hadith
Blind motion image deblurring using canny edge detector with generative adversarial networks / Idriss Moussa Idriss
No full textBlind motion image deblurring has been investigated widely in recent years. Many methods and scheme shave been proposed so far, with respectto edge-preserving. Edge information transfers the essential details of an image which is a primary factor impacting the visual effect. Edge-preserving is an important attribute during the process of image restoration. The main objective of deblurring is to generate a good approximation of theory original image from the blurry image. However, blind motion deblurring has remained challenging task for image processing and computer vision. Most of the existing algorithms rely on MAP (Maximuma Priori) and VB (Variational Bayesian)which are based on deterministic and stochastic methodologies, respectively, to estimate the blur function. MAP and VB both rely on particular assumptions to find the sources of the blur which make it difficult to use the edge-preserving treatment during the deblurring process. Therefore, including an edge-preserving treatment in the deblurring process would overcome these barriers as edges are the essential attribute of image information. This study proposes a combination approach of Canny edge detector with generative adversarial networks (GANs) to reconstruct the blurry image with edge-preserving without prior knowledge of the blurred image. The proposed method takes the blurred image with its detected edge, enhances it using Canny edged etectorasan input, and producesa corresponding detected restored sharp edge with its image, evaluated by the GANs. Then there stored sharp image is compared against the ground truth (sharp) image. Experiment s are conducted using the GoPro dataset. The proposed combined method has achieved good deblurring with edge-preserving results based on the evaluation metrics used
A framework of meaningful sharing behavior of authentic holy Quran content on facebook / Suraya Ika Tamrin
No full textApparently, people have witnessed a rapid diffusion and adoption of social media platforms in finding and sharing information, including the religious contents of Quran. This exercise has led to unhealthy sharing behavior of online Quran content among the users and the increase number of disseminations of unauthenticated online Quran content. There are several previous researches have been conducted in the context or religious content sharing in social media. However, there are limited works done to address both mentioned issues above. Thus, it is vital to continuously monitor this Quran content disseminated in the social media are authentic and not changed. This research embarks on four main objectives, 1) to investigate the current behavior of Facebook users in sharing Quran content; 2) to develop a framework to authenticate the online Quran content shared on Facebook; 3) to evaluate the factors that associated with Quran content sharing on Facebook, and 4) to validate a framework to authenticate the online Quran content shared on Facebook. To achieve these objectives, this research applied sequential mixed method, which are i) qualitative netnography analysis and ii) quantitative survey questionnaire. The qualitative netnography focused on 92 Quran related groups in Facebook for the duration of 12 months in two different data collection series. For the quantitative data collection, it involved 587 respondents based on convenient sampling method in Facebook.
The finding shows there are 12 validated constructs: Verification, legality, trustworthy, privacy, self-efficacy, response efficacy, response cost, perceived severity, perceived vulnerability, fear, authentication motivation and healthy sharing behavior. Whereby, each construct shows significant relationship at p >0.05. The conclusion of the research shows that 26 hypotheses are supported with R2 of the healthy sharing behavior is at 66.2% and 5 hypotheses are not supported. The contribution of this research is in 2 folds which are, 1) in the body of knowledge – 12 additional constructs are required to show healthy sharing behavior; 2) as for the stakeholders, Facebook users, Muslim community, and Malaysia Islamic authority, would be able to use this framework as a guidance in executing healthy behavior in sharing Quran content
Carbon stock in Pulau Pintu Gedong mangrove forest, Malaysia / Mysha Farzana Peuny
No full textMangrove forests are regarded as the most significant carbon (C) sink in the tropics. They could play an important role in tackling climate change mitigation by reducing deforestation in the environmental, social, and economic sphere. The aims of the present study were to assess the species composition, phytosociological conditions and the ecosystem carbon stock in the tidal gradient of mangrove forest in Pulau Pintu Gedong in the west coast of Peninsular Malaysia. Blue Carbon stock was quantified in soil, downed wood and trees, saplings and seedlings components. The mean ecosystem carbon stock was about 783.58 ± 135.93 Mg /ha at two stations (one is fringe mangrove, and another is interior mangrove). Soil organic carbon stock contributed the largest share with a mean value of 636.55±87.36 Mg/ha. Approximately 632349.06 Mg C were estimated for the study site covering total of 807 ha of mangrove forest area. The prospective carbon pool from two stations of mangrove range from 3228.50 to 2522.98 Mg of
A tridimensional bone structure analysis of Cheryl Ann Fernando character in the movie Adiwiraku / Vanidah Imran
No full textAdiwiraku brings about real-life settings about a teacher’s determination to inspire and
motivate her students to reach for greater heights in life. The character is defined by what
he or she does, not by what they say. Hence, this research study analyses the physical,
sociology and psychological aspects of the female protagonist in dealing with conflicts
and challenges as a teacher. Psychological development of the character is a critical
influence in order to understand the character’s behaviour. This research uses qualitative
research mode with Reissman’s performative analysis method as the study design. The
selected design of this study is to analyse the application of the Tridimensional Bone
Structure to analyse the female teacher protagonist, which influenced the students’
behaviour and in encouraging the learning of the English language. The ultimate finding
shows that, although her physical attributes may have deemed her as an outsider, but,
Cheryl Ann Fernando won over the Malay community’s acceptance, admiration and trust.
In the given sociological conditions, she is flexible, adaptable and nurtures the students
with values, in the classroom and also their personal aspect. Her various teaching methods
to uplift the students’ English standards signifies the psychological aspects of her values
and character. This research study proves that the ‘Tridimensional Bone Structure’ is an
approach that can be used in developing and determining the behaviour and
characteristics of the protagonist character in films, which can provide an incentive of
aspirations to the Malaysian community
Study of drag reduction by using guar gum and gum Arabic mixtures / Abdul Razzak Kabbara
No full textSince Toms documented drag reduction in 1949, many researched all over the world
are exploring different drag reducing agents hoping to better understand the drag
reduction phenomenon and hoping to find best agents for different applications. Many
drag reducing agents offered great drag reduction but due to their negative effects on the
environment, the focus is switching to biopolymers, a natural ecofriendly alternative. So
far, few studies explored the potential of biopolymers to reduce drag, and fewer number
of studies tested biopolymer mixers. In this research, guar gum and gum Arabic mixtures
of three different ratios at 300 ppm concentration were examined using a closed loop
piping system. To study drag reduction as well as the mixture’s resistance to heat, two
tests were performed for each mixture both at bulk temperature of 30°C. One test without
any heating while the other involved continuous heat flux of 3400 W. Several interesting
conclusions were found. First, as the ratio of guar gum increased in the mixture, the drag
reduction increased. The best drag reduction of 22.65% was achieved by the mixture
composed of 50% Guar Gum with 50% Gum Arabic. Finally, for all the fluids considered
in the study and for velocities greater than 1 m/s, heating reduced drag reduction
Synthesis and evaluation of properties and energy transportation characteristics of gum Arabic and gum guar in heat exchanger / Suga Ganeshan Kalaichalvan
No full textCurrent interest in “oil and gas” sectors, as well as in the use of reduced pumping
energy, have driven the use of drag lowering additives for such sectors. Slurry
transportation by cost-effective and environmentally friendly means by using
biodegradable compounds, as the additives can achieve these advantages. To examine the
drag lowering polymeric additive in the turbulent flow regime, a closed loop of an
insulated circular (ID 41.5mm) aluminium pipe test rig was used. Gum guar and gum
Arabic were the adaptive or drag lowering agent used by mixing in distilled water. For
the experimental research, the pulp disintegrator was utilized to generate a diluted
combination of additive in distilled water. For composition in all the cases, some general
correlations for pressure drop, friction factor, and drag reduction percentages were
established by applying heat and without heat to the following solution. The degree of
pressure drop decrease (drag reduction) was depending on concentrations and technique
of dispersion. Additive concentration, flow velocity and temperature of the water affected
the pressure drop results. An empirical correlation was used to verify the water data and
found satisfactory results with error about 8% in the specified range of Reynolds number
(18,000 to 167,000). In the present work Guar Gum (GG) and Gum Arabic (GA) solutions
were investigated individually, and then mixture of the two were also investigated for
drag reduction. For the mixture of GG:GA-70:30 (200 ppm of additive concentration) the
decrease in drag reduction was in between 30-35% without heat and at lower velocity and
20-25% at higher velocity and with and without heating. From this experimental research,
it showed that the Gum Guar was more helpful in enhancing the drag reduction in
pipelines compared to that of Gum Arabic alone in the solution and a little addition of on
in the other have changed significant drag reduction data
Antioxidant activities and chemical composition of hot water-soluble extracts and fractions of selected Schizophyllum commune Fr. strains / Alyaa Salah Rashid Al-Salihi
No full textOxidative stress is a conjoint pathological mechanism that can be triggered by free radicals leading to cellular senescence or apoptosis. Antioxidants have the potential to inhibit free radicals’ generation and balance the irregulated oxidative stress to restore cellular homeostasis. Schizophyllum commune, also known as the split-gill mushroom, is well-known for its nutritional values and bioactive compounds. This study aimed to investigate the antioxidant activity and chemical composition of the hot water extracts of selected strains of S. commune including natural, gamma-irradiated and hybrid strains. The fruiting bodies of different strains of S. commune were subjected to hot water extraction and the extracts were evaluated by radical scavenging, and reducing capacity assays. Results showed that, overall, the antioxidant activity of the various strains was comparable. The natural strain W and the strain obtained when strain W was subjected to gamma-irradiation at a dose of 4000 Gy (W4000) consistently exhibited high antioxidant activities in all assays and they were either comparable or higher than common edible mushrooms, Pleurotus pulmonarius and Agaricus bisporus. Moreover, the gamma-irradiated strains R2000 and R4000 exhibited higher reducing activities (0.40 and 0.41 mmol Fe2+/g extract) than the parental strain R (0.27 mmol Fe2+/g extract). Furthermore, the hybrid strains WR and RW showed higher scavenging activities towards 2,2 diphenyl-1-picylhydrazyl radicals (1.40 and 1.45 mmol TE/g extract) than the parental strain R (1.17 mmol TE/g extracts), but lower than the parental strain W (1.78 mmol TE/g extract). There is a strong correlation between the antioxidant activity of the extracts and the levels of flavonoid and phenolic compounds (p < 0.01). In order to determine the nature of antioxidative components in the hot water extracts of S. commune, the extracts of strains W and W4000, were fractionated to yield fractions with distinct chemical components. Results indicated that the phenolics- and flavonoids-rich ethyl acetate and ethanol fractions exhibited higher scavenging activities towards DPPH radicals, and ferric reducing activities compared to the fractions containing mostly water-soluble components. Similar trends were observed for both W and W4000 strains. Our findings suggest that the observed antioxidant activities of the hot water extracts of S. commune is mainly attributed to the water-soluble, low- molecular-weight compounds rather than the water-soluble components such as polysaccharides and proteins which make up the bulk of the water extracts
Speaker identification through feature fusion based deep learning / Rashid Jahangir
No full textSpeech is a powerful medium of communication that always conveys rich and useful information, such as gender, accent, and other unique characteristics of a speaker. These unique characteristics enable researchers to recognise human voice using artificial intelligence techniques that are important in the areas of security and surveillance, electronic voice eavesdropping, mobile banking, mobile shopping and speaker identification (SI). Speaker identification refers to the process of recognising human voices using artificial intelligence techniques. In the speaker identification process, extracting discriminative and salient features from speaker utterances is an important task to accurately identify speakers. Recently, various short-time features, such as Mel frequency cepstral coefficients (MFCC) have been utilised due to their capability to capture the repetitive nature and efficiency of signals. Various studies have shown the effectiveness of the aforementioned features in correctly identifying speakers. However, the performances of these features degrade on complex speech datasets, and therefore, these features fail to accurately identify speaker characteristics. To address this problem, this study proposes a novel fusion of MFCC and time-based features (MFCCT), which combines the effectiveness of MFCC and time-domain features to improve the accuracy of text-independent speaker identification (SI) systems. On the other hand, recent advancements in deep learning have gained the attention of researchers working in the field of automatic speaker identification (SI). Therefore, the extracted MFCCT features were fed as input to a deep neural network (DNN) to construct the speaker identification model. The experimental results showed that the proposed MFCCT features coupled with DNN outperformed existing baseline MFCC and time-domain features on the LibriSpeech dataset. In addition, DNN obtained better classification results compared with the other five machine learning algorithms that were recently utilised in speaker recognition. Finally, this study also investigated the effectiveness of one-level (identifying speaker) and two-level (identify the gender first and then identify the speaker) classification methods for speaker identification. The experimental results showed that two-level classification presented better results compared to one-level classification. It is believed that the proposed features and two-level classification model for identifying a speaker can be widely applied to different types of complex speaker datasets. Moreover, our proposed features and classification method can be adopted in several domains working in the area of voice recognition