Search Results

1 - 10 of 70 items

  • Author: M. Ahmed x
Clear All Modify Search
Clustering Large-Scale Data Based On Modified Affinity Propagation Algorithm

Abstract

Traditional clustering algorithms are no longer suitable for use in data mining applications that make use of large-scale data. There have been many large-scale data clustering algorithms proposed in recent years, but most of them do not achieve clustering with high quality. Despite that Affinity Propagation (AP) is effective and accurate in normal data clustering, but it is not effective for large-scale data. This paper proposes two methods for large-scale data clustering that depend on a modified version of AP algorithm. The proposed methods are set to ensure both low time complexity and good accuracy of the clustering method. Firstly, a data set is divided into several subsets using one of two methods random fragmentation or K-means. Secondly, subsets are clustered into K clusters using K-Affinity Propagation (KAP) algorithm to select local cluster exemplars in each subset. Thirdly, the inverse weighted clustering algorithm is performed on all local cluster exemplars to select well-suited global exemplars of the whole data set. Finally, all the data points are clustered by the similarity between all global exemplars and each data point. Results show that the proposed clustering method can significantly reduce the clustering time and produce better clustering result in a way that is more effective and accurate than AP, KAP, and HAP algorithms.

Open access
Pyrrolizine-5-carboxamides: Exploring the impact of various substituents on anti-inflammatory and anticancer activities

Abstract

Towards optimization of the pyrrolizine-5-carboxamide scaffold, a novel series of six derivatives (4a-c and 5a-c) was prepared and evaluated for their anti-inflammatory, analgesic and anticancer activities. The (EZ)-7-cyano-6-((4-hydroxybenzylidene)amino)-N-(p-tolyl)-2,3-dihydro-1H-pyrrolizine-5-carboxamide (4b) and (EZ)-6-((4-chlorobenzylidene)-amino)-7-cyano-N-(p-tolyl)-2,3-dihydro-1H-pyrrolizine-5-carboxamide (5b) bearing the electron donating methyl group showed the highest anti-inflammatory activity while (EZ)-6-((4-chlorobenzylidene)amino)-7-cyano-N-phenyl-2,3-dihydro-1H-pyrrolizine-5-carboxamide (5a) was the most active analgesic agent. Cytotoxicity of the new compounds was evaluated against the MCF-7, A2780 and HT29 cancer cell lines using the MTT assay. Compounds 4b and 5b displayed high anticancer activity with IC 50 in the range of 0.30–0.92 μmol L−1 against the three cell lines, while compound (EZ)-N-(4-chlorophenyl)-7-cyano-6-((4-hydroxybenzylidene)-amino)-2,3-dihydro-1H-pyrrolizine-5-carboxamide (4c) was the most active against MCF-7 cells (IC 50 = 0.08 μmol L−1). Both the anti-inflammatory and anticancer activities of the new compounds were dependent on the type of substituent on the phenyl rings. Substituents with opposite electronic effects on the two phenyl rings are preferable for high cytotoxicity against the MCF-7 and A2780 cells. COX inhibition was suggested as the molecular mechanism of the anti-inflammatory activity of the new compounds while no clear relationship could be observed between COX inhibition and anticancer activity. Compound 5b, the most active against the three cell lines, induced dose-dependent early apoptosis with 0.1–0.2 % necrosis in MCF-7 cells. New compounds showed promising drug-likeness scores while the docking study revealed high binding affinity to COX-2. Taken together, this study highlighted the significant impact of the substituents on the anti-inflammatory and anticancer activity of pyrrolizine-5-carboxamides, which could help in further optimization to discover good leads for the treatment of cancer and inflammation.

Open access
Evaluation of Different Fungicides Against Aspergilus flavus and their Comparative Efficacy Upon Germination of Infected Rice Seeds

Abstract

Aspergilus flavus is the most common seed born fungus that deteriorates the seed quality and minimizes the export value of the rice all over the world. Fungicides are the most successful and commonly used way to manage any fungi but more use of fungicides have resulted evolution in the seed born fungi so efforts are required off and on to stay ahead of the fungal races. Keeping in view, the present research work was conducted to evaluate different fungicides against A. flavus and their comparative efficacy upon the infected rice seeds. Experiment was laid out in completely randomize design with varying concentrations of fungicides (20, 40, 60 and 80 ppm) under laboratory conditions. Statistical results shown significant reduction in mycelial growth and improved the seed germination as well. The results were significantly better when the fungicides were used at 80 ppm, as compared to low concentrations. Regarding mycelial growth, Kumulus-DF and Cabrio-Top were comparative to each other, followed by Trimiltox-Forte, Cordate and Copper oxychloride, while for the other attribute of infected grain germination Kumulus-DF proven better in comparison with Trimiltox-forte and Cabrio-Top, followed by Cordate and Copper oxychloride.

Open access
Development of a three dimensional circulation model based on fractional step method

Abstract

A numerical model was developed for simulating a three-dimensional multilayer hydrodynamic and thermodynamic model in domains with irregular bottom topography. The model was designed for examining the interactions between flow and topography. The model was based on the three-dimensional Navier-Stokes equations and was solved using the fractional step method, which combines the finite difference method in the horizontal plane and the finite element method in the vertical plane. The numerical techniques were described and the model test and application were presented. For the model application to the northern part of Ariake Sea, the hydrodynamic.

Open access
Synthesis and characterization of Zn/ZnO microspheres on indented sites of silicon substrate

Abstract

Self-assembled Zn/ZnO microspheres have been accomplished on selected sites of boron doped P-type silicon substrates using hydrothermal approach. The high density Zn/ZnO microspheres were grown on the Si substrates by chemical treatment in mixed solution of zinc sulfate ZnSO4·7H2O and ammonium hydroxide NH4(OH) after uniform heating at 95 °C for 15 min. The Zn/ZnO microspheres had dimensions in the range of 1 μm to 20 μm and were created only on selected sites of silicon substrate. The crystal structure, chemical composition and morphology of as-prepared samples were studied by using scanning electron microscope SEM, X-ray diffraction XRD, energy dispersive X-ray spectroscopy EDS, Fourier transform infrared spectroscopy FT-IR and UV-Vis diffuse reflectance absorption spectra DRS. The energy band gap Eg of about 3.28 eV was obtained using Tauc plot. In summary, this study suggests that interfacial chemistry is responsible for the crystal growth on indented sites of silicon substrate and the hydrothermal based growth mechanism is proposed as a useful methodology for the formation of highly crystalline three dimensional (3-D) Zn/ZnO microspheres.

Open access
Exploring The Suitability Of Incorporating Tiger Nut Flour As Novel Ingredient In Gluten-Free Biscuit

Abstract The effect of using tiger nut flour to improve the functional properties of gluten-free biscuit was explored. Corn flour in the biscuit formulation was replaced at three levels, 10, 20, and 30% with tiger nut flour (TNF). Biscuit containing only corn flour was used as control. Prepared biscuits were analyzed for their proximate composition, physical properties, diameter, thickness, color, texture, and were subjected to measurements using differential scanning calorimetery (DSC) and scanning electron microscopy (SEM).

Incorporation of tiger nut flour resulted in a significant increase in fibre and ash contents and in a decrease in protein content. The spread ratio of the biscuits increased significantly by increasing TNF content, which is considered a desirable quality attribute. Tiger nut-containing biscuits exhibited lower total color difference ΔE value compared to the control sample.

Thermal characteristics of TNF-containing biscuits differed significantly (P≤0.05) from the control where TNF resulted in decreased onset gelatinization temperature (To) and peak temperature (Tp). Furthermore, enthalpies of control biscuits were significantly higher than of those containing TNF; that might be due to partial gelatinization since their enthalpies were smaller than in control biscuits.

Measurement of baked biscuits texture showed that hardness and resilience values decreased when TNF content in the biscuit formulation increased. Microscopic observation revealed that TNF-containing biscuits had the most uniform and homogeneous pore distributions. These attributes probably positively influenced the quality with better surface characteristics. The results of this study revealed that incorporating TNF at the ration of 20% resulted in biscuits of superior technological quality expressed in shape, cross section structure, hardness, and surface appearance

Open access
Analysis of Fatigue Crack Growth in Ship Structural Details

Abstract

Fatigue failure avoidance is a goal that can be achieved only if the fatigue design is an integral part of the original design program. The purpose of fatigue design is to ensure that the structure has adequate fatigue life. Calculated fatigue life can form the basis for meaningful and efficient inspection programs during fabrication and throughout the life of the ship. The main objective of this paper is to develop an add-on program for the analysis of fatigue crack growth in ship structural details. The developed program will be an add-on script in a pre-existing package. A crack propagation in a tanker side connection is analyzed by using the developed program based on linear elastic fracture mechanics (LEFM) and finite element method (FEM). The basic idea of the developed application is that a finite element model of this side connection will be first analyzed by using ABAQUS and from the results of this analysis the location of the highest stresses will be revealed. At this location, an initial crack will be introduced to the finite element model and from the results of the new crack model the direction of the crack propagation and the values of the stress intensity factors, will be known. By using the calculated direction of propagation a new segment will be added to the crack and then the model is analyzed again. The last step will be repeated until the calculated stress intensity factors reach the critical value.

Open access
Evaluation of Chitosan/Fructose Model as an Antioxidant and Antimicrobial Agent for Shelf Life Extension of Beef Meat During Freezing

Abstract

In the present study the effect of chitosan/fructose Maillard reaction products (CF-MRPs) as antioxidant and antimicrobial agents was evaluated and applied on minced beef meat during frozen storage. Antioxidant and antimicrobial properties of chitosan-fructose complexes were tested. Anti-oxidant properties were measured by the DPPH, β-carotene and ABTS methods. These three methods showed the same profile of antioxidant activity. Chitosan with 4% fructose autoclaved for 45 min (CF9) showed to have the most effective antioxidant activity. It was demonstrated that the browning product exhibited antioxidant activity. For antimicrobial activity, most chitosan-fructose complexes were less effective than chitosan. Thus, MRPs derived from chitosan-sugar model system can be promoted as a novel antioxidant to prevent lipid oxidation in minced beef. Chitosan-sugar complex could be a potential alternative natural product for synthetic food additive replacement that would additionally meet consumer safety requirement.

Open access
Effect of Tillage and Organic Mulches on Growth, Yield and Quality of Autumn Planted Maize (Zea Mays L.) and Soil Physical Properties

Abstract

The research work was conducted to see the effect of organic mulches and tillage practices on growth, yield and quality of autumn planted maize and soil physical properties. Four types of tillage practices i.e. conventional tillage, zero tillage, bar harrow tillage, subsoiler tillage and two types of mulching material i.e. wheat straw mulch and saw dust mulch was used. The mulching material was partially incorporated in the field after germination of crop. The experiment was carried out in randomized complete block design (RCBD) with three replications. Control treatment was kept for comparison. All other practices were kept uniform throughout the crop period. Data about growth and yield components were collected and analyzed statistically by fisher analysis of variance and treatment significance was measured by significant difference test at 5v% level. The results showed that zero tillage + wheat straw mulch gave maximum 1000-grain weight (341.67 g) and grain yield (6.33 t ha-1) and it was followed by conventional tillage + saw dust mulch (4.92 t ha-1). Higher protein content was recorded in Subsoiler tillage (10.26 %). Conducive soil physical conditions were observed in the zero tillage practices over the other tillage practices. On the basis of these results it could be proposed that the tillage and mulching is a very important practice to increase the yield of crop. Among different practices, zero tillage with wheat straw mulching gave maximum yield and net benefits.

Open access
Structural optical and magnetic properties of transition metal doped ZnO magnetic nanoparticles synthesized by sol-gel auto-combustion method

Abstract

Transition metals, such as chromium (Cr) and manganese (Mn) doped zinc oxide (ZnO) magnetic nanoparticles, were synthesized via sole gel auto-combustion method. The prepared magnetic (Zn1−(x+y)MnxCryO, where x, y = 0, 0.02, 0.075) nanoparticles were calcined in an oven at 6000 °C for 2 hours. The morphologies of the nanoparticles were investigated using different techniques. X-ray diffraction (XRD) analysis revealed that the hexagonal wurtzite structure of the synthesized nanoparticles was unaffected by doping concentration. The crystallite size measured by Scherrer formula was in the range of 32 nm to 38 nm at different doping concentrations. Nanosized particles with well-defined boundaries were observed using a field emission scanning electron microscopy (FE-SEM). Fourier transform infrared (FT-IR) spectra showed a wide absorption band around 1589 cm−1 in all the samples, corresponding to the stretching vibration of zinc and oxygen Zn–O bond. A blue shift in optical band gaps from 3.20 eV for ZnO to 3.08 eV for Zn0.85Mn0.075Cr0.075O nanoparticles was observed in diffuse reflectance spectra, which was attributed to the sp-d exchange interactions. The field-dependent magnetization M-H loops were measured using vibrating sample magnetometer (VSM). The VSM results revealed diamagnetic behavior of the ZnO nanoparticles which changed into ferromagnetic, depending on the doping concentration and particle size. The compositions of Zn, Cr, Mn and O in the prepared samples were confirmed by using the energy dispersive X-ray spectroscopy (EDX). Our results provided an interesting route to improve magnetic properties of ZnO nanoparticles, which may get significant attention for the fabrication of magnetic semiconductors.

Open access