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Search Results: 1 - 10 of 8950 matches for " Tahir Ahmad "
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The Development and Characterization of Zirconia-Silica Sand Nanoparticles Composites  [PDF]
Tahir Ahmad, Othman Mamat
World Journal of Nano Science and Engineering (WJNSE) , 2011, DOI: 10.4236/wjnse.2011.11002
Abstract: The present study aims to develop zirconia-Silica sand nanoparticles composites through powder processing route and to study the physical properties, mechanical properties and microstructure of the composites. Zirconia based silica sand nanoparticles composite with 5, 10, 15 and 20 wt.% were developed through powder processing technique and sintered at 1500 ℃ for two hours. A decreasing trend of green density however an improvement in sintered density was observed. Also the addition of silica sand nanoparticles with 20 wt.% increased the hardness up to 12.45 GPa and microstructures indicated the diffusion mechanism of silica sand nanoparticles into pore sites of the composites.
Pengitlakan Satu Kaitan Koszul Mendatar (TS2,Pi, S2) kepada (E,q,B)
Tahir Ahmad
Matematika , 2000,
Abstract: In this paper several results for connection on general vector bundle(E,q,B) are revealed. In the beginning these results are deduced from a Koszul connection for (TS2, p, S2). Further deduction produces some results in transportation locally; between two charts, and globally; isomorphism between two vector bundles with the same base manifold.
Digital Space of Flat EEG
Nazihah Ahmad,Tahir Ahmad
Lecture Notes in Engineering and Computer Science , 2012,
Hyperspherical Manifold for EEG Signals of Epileptic Seizures
Tahir Ahmad,Vinod Ramachandran
Journal of Applied Mathematics , 2012, DOI: 10.1155/2012/926358
Abstract: The mathematical modelling of EEG signals of epileptic seizures presents a challenge as seizure data is erratic, often with no visible trend. Limitations in existing models indicate a need for a generalized model that can be used to analyze seizures without the need for apriori information, whilst minimizing the loss of signal data due to smoothing. This paper utilizes measure theory to design a discrete probability measure that reformats EEG data without altering its geometric structure. An analysis of EEG data from three patients experiencing epileptic seizures is made using the developed measure, resulting in successful identification of increased potential difference in portions of the brain that correspond to physical symptoms demonstrated by the patients. A mapping then is devised to transport the measure data onto the surface of a high-dimensional manifold, enabling the analysis of seizures using directional statistics and manifold theory. The subset of seizure signals on the manifold is shown to be a topological space, verifying Ahmad's approach to use topological modelling.
Rhinosinusitis in north-eastern Nigeria: computerized tomographic scan findings
BM Ahmad, AA Tahir
Nigerian Journal of Surgical Research , 2003,
Abstract: Background: Computed tomographic scan (CT) is a useful imaging modality for infection of the paranasal sinuses. Method: Retrospective study of 52 patients seen with evidence of rhinosinusitis on CT scan of the paranasal sinuses. Results: There was a male preponderance with a M: F ratio of 1.7:1 ad age range 9 – 63 years. Mucosal thickening (80.2%) and engorged turbinates (65.4%) were the most common findings on CT; while the maxillary sinuses was the most affected sinus and the sphenoid the least. There was no intracranial complication noted. However, 9.6% of the patients had orbital complications. Conclusion: CT scan has confirmed the absence of life threatening intracranial complications and clearly defined the extent if the disease. Key Words: CT Scan, Rhinosinusitis, North-Eastern Nigerians. Nigerian Journal of Surgical Research Vol.5(1&2) 2003: 110-113
Permukaan Reimann: S2
Tahir bin Ahmad
Matematika , 1993,
Abstract: Kertas ini akan membuktikan bahawa sfera yang berjejari 1 unit dalam 3 matra merupakan sebuah permukaan Reimann. Pembuktian-pembuktian ini dirangka khas supaya mudah dengan penggunaan beberapa teorem yang asas dari Analisis Kompleks, Geometri Kerbezaan, Topologi dan juga koordinat sfera dan silinder. Pembuktian secara pembinaan dan peranggahan digunakan dalam makalah ini.
The Professional Medical Journal , 2008,
Abstract: Objective: To determine whether concomitant use of vitamins B1, B6, B12 along with low dose of diclofenac sodium causesquicker pain relief in patients of acute lumbago compared with diclofenac sodium alone. Design: A randomized clinical trial. Setting: SurgicalDepartment of C M H Attock. Period: From September 2004 to August 2005 Patients & Methods: A total of 50 patients were selected forthe study. The patients complaints were of acute lumbago of less than 3 days duration with severe impairments of movements. The age groupof patients was between 20 and 65 years. The patients were randomly assigned into two groups. Group I was prescribed tablet diclofenacsodium 25mg along with vitamin B-complex containing combination of 100mg thiamine nitrate (B1), 100mg pyridoxine hydrochloride (B6), and200mcg cyanocobalmine (B12) three times a day. Group II patients were prescribed 25mg of tablet diclofenac sodium alone. Improvement inthe intensity of pain at rest and during movements (as assessed by the patients) was noted in accordance to visual analogue scale 1 to 10.The effectiveness of diclofenac sodium in combination with vitamin-B complex with diclofenac sodium alone was judged on the basis of extentof pain relief after 7 days of treatment. Results: A total of 25 patients were treated with combination of diclofenac sodium & vitamin-B complex(Group I) and 25 were treated with diclofenac sodium alone (Group II). As far as the extent of pain relief in first 7 days is considered, 22 patients(88%) belonging to group I and 10 patients (12%) belonging to group II had an excellent pain relief and were able to carry on with their normalroutine activities. Remaining 3 patients in group I were completely relieved of pain in next 3 days while 15 patients in group II had to completeanother 10 days for complete cure. To test the statistical significance of the result chi-square test was applied and the result showed thatpatients of Group I responded significantly well to the treatment as compared to those in Group II. Conclusion: Using the parameters of painrelief and movements of vertebral column, the combination of diclofenac sodium & vitamin-B complex was found to be more effective modeof treatment as the duration of treatment and the dosage of diclofenac sodium was less and also relief of pain was more rapid.
Remote Sensing Data Application to Monitor Snow Cover Variation and Hydrological Regime in a Poorly Gauged River Catchment—Northern Pakistan  [PDF]
Samreen Abdul Hakeem, Muhammad Bilal, Arshid Pervez, Adnan Ahmad Tahir
International Journal of Geosciences (IJG) , 2014, DOI: 10.4236/ijg.2014.51005

Snow- and glacier-nourished river basins located in the Himalaya-Karakoram-Hindukush (HKH) ranges supply a significant amount of discharge in River Indus upstream Tarbela Dam. It is, hence, important to comprehend the cryosphere variation and its relationship to the stream flow in these high-altitude river catchments. The MODIS remotely sensed database of snow products was chosen to examine the average annual snow and glacier cover (cryosphere) variations in the Shigar River basin (poorly gauged mountainous sub-catchment of the Indus River). Hydrological regime in the area was investigated through monthly database of observed stream fluxes and climate variables (precipitation and mean temperature) for the Shigar River catchment. Analysis indicated the usefulness of remote sensing techniques for estimation of the snow cover variation in the poorly or un-gauged high-elevation catchments of the HKH zone. Results also showed that Shigar River discharge was influenced mainly by the seasonal and annual snow cover area (SCA) variation and the temperature seasonality. Moreover, it is important to uncover such inter-relationship of stream flow, climate variables and snow cover in the poorly gauged high-altitude catchments of Karakoram region for better water resource management and accurate flood hazards predictions at Tarbela.

Pembinaan Homeomorfisma dari Sfera ke Elipsoid
Liau Lin Yun,Tahir Ahmad
Matematika , 2003,
Abstract: In this paper, we present the construction of homeomorphism from unit sphere; S2 to ellipsoid which is one unit in xy-axis and its poles are at z = 2 and z = 2; E2 through Riemann surface structures. Proving techniques by construction and contradiction are highlighted.
Studying the Effects of Adding Silica Sand Nanoparticles on Epoxy Based Composites
Tahir Ahmad,Othman Mamat,Rafiq Ahmad
Journal of Nanoparticles , 2013, DOI: 10.1155/2013/603069
Abstract: The research about the preparation of submicron inorganic particles, once conducted in the past decade, is now leading to prepare polymer matrix composite (PMC) reinforced with nanofillers. The objective of present research is to study the modified effects of reinforcement dispersion of nanoparticle silica in epoxy resin on the physical properties, mechanical and thermal behaviour, and the microstructure of resultant composites. Stirrer mixing associated with manual mixing of silica sand nanoparticles (developed in our earlier research) (Ahmad and Mamat, 2012) into epoxy was followed by curing being the adopted technique to develop the subject nanocomposites. Experimental values showed that 15?wt.% addition of silica sand nanoparticles improves Young’s modulus of the composites; however, a reduction in tensile strength was also observed. Number of holes and cavities produced due to improper mixing turn out to be the main cause of effected mechanical properties. Addition of silica sand nanoparticles causes a reduction in degree of crystallinity of the nanocomposites as being observed in differential scanning calorimetry (DSC) analysis. 1. Introduction Nowadays industrial and academic research laboratories are focusing much of their efforts to develop and improve physical, mechanical, and electrical properties of polymer nanocomposites. Their interest to develop such composites is mainly because of the fact that nanoparticles present a high surface-to-volume ratio which may induct unique properties to these nanocomposites as compared to macro-scale composites [1]. Andritsch et al. [2] prepared nanocomposites filled with SiO2, Al2O3, and AIN with an average particles size from 22?nm to 10?nm and studied the nanoparticles dispersion and DC breakdown strength. They observed the highest DC breakdown strength for 0.5?wt.% for two component system. It was also noticed that the DC breakdown strength increased with 10?wt.% as compared to 2 and 5?wt.% and again decreased with 15?wt.% nano-fillers. Yasmin et al. [3] studied the dispersion of clay nanoparticles in epoxy-based composites using a three roll mill with the concentration of 1–10?wt.%. This technique was found highly efficient and environmentally friendly due to excellent dispersion of nanoparticles within a short time. Elastic modulus was improved up to 80% with 10?wt.% addition of clay nanoparticles in epoxy. Absence of any improvement in tensile strength of the nanocomposites over pure epoxy was due to the clustering of nanoparticles and/or to the occasional occurrence of nano- to microsize voids in
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