NUMERICAL SIMULATION OF FLOW OVER TWO SIDE-BY-SIDE CIRCULAR CYLINDERS

In the present paper, the unsteady, viscous, incompressible and 2-D flow around two side-by-side circular cylinders was simulated using a Cartesian-staggered grid finite volume based method. A great-source term technique was employed to identify the solid bodies (cylinders) located in the flow field and boundary conditions were enforced by applying the ghost-cell technique. Finally, the characteristics of the flow around two side-by-side cylinders were comprehensively obtained through several computational simulations. The computational simulations were performed for different transverse gap ratios (1.5≤T/D≤4) in laminar (Re=100,200) and turbulent (Re=104) regimes, where T and D are the distance between the centers of cylinders and the diameter of cylinders, respectively. The Reynolds number is based on the diameter of cylinders,D. The pressure field and vorticity distributions along with the associated streamlines and the time histories of hydrodynamic forces were also calculated and analyzed for different gap ratios. Generally, different flow patterns were observed as the gap ratio and Reynolds number varied. Accordingly, the hydrodynamic forces showed irregular variations for small gaps while they took a regular pattern at higher spacing ratios.     

Statistical modeling of crack growth and reliability assessment of high-density polyethylene

In this work, a statistical evaluation of the crack-growth process in high-density polyethylene (HDPE) was carried out. The specimens were compression molded from virgin, molding-grade HDPE. Edgenotched specimens for replicate fatigue testing were prepared from compression-molded sheets. Fatigue test results were then analyzed, and it is shown that if the crack-growth process can be characterized as a random process following a power-law-type behavior, then the time to reach a critical crack length will be distributed according to an inverted lognormal model.     

New scale invariant template matching technique using hyper space image representation

A new approach for the template image matching is being presented. The method first converts the image into edges, then, the vital information of these edges has been presented as a set of vectors in a four dimensional hyper-space. A modified Radon Transform has been proposed to facilitate this vectorization process. All the above processing is being done offline for the main image of the area. The template image has also been vectorized in a same fashion in real time which is to be matched with the main image. A vector matching algorithm has been proposed to deliver match location with a very low computational cost. It works for a wide range of template scaling and noise conditions which were not there in the previous algorithms found in the literature.     

Penetration Depth in Nanoparticles Incorporated Radiofrequency Hyperthermia into the Tissue: Comprehensive Study with Histology and Pathology Observations

In present study, the effective penetration of radiofrequency (RF) induced gold decorated iron oxide nanoparticles (GS@IONPs) hyperthermia was investigated. The effective penetration depth of RF also the damage potency of hyperthermia was evaluated during histopathology observations which were done on the chicken breast tissue and hepatocellular carcinoma (HCC) models. The thermal damages are well‐ documented in our previous cellular study which was engaged with potency of RF hyperthermia in Epithelial adenocarcinoma (MCF‐7) and fibroblast (L‐929) cells deaths [1]. In recent work, PEGylated iron oxide nanoparticles (IONPs) were used as base platform for gold magnetic nanoparticles (GS@IONPs) formation. The 144.00015 MHz, 180W RF generator was applied for stimulating the nanoparticles. The chicken breast tissue and the hepatocellular tumor model was considered in the experimental section. In histology studies, the structural changes also the effective penetration depth of RF induced nanoparticles was observed through microscopic monitoring of the tissue slices in histology observations (Gazi medical school). The highest damage level was seen in 8.0 µm tissue slices where lower damages were seen in depth of 1.0 cm and more inside tissue. The histology observations clarified the effective penetration depth of RF waves and irreversible damages in the 2.0 cm inside the tissue.Inspec keywords: nanomedicine, tumours, biomedical materials, cellular biophysics, nanoparticles, gold, cancer, hyperthermia, magnetic particles, iron compounds, radiation therapyOther keywords: Au‐Fe₃ O₄ , depth 1.0 cm, depth 8.0 mum, power 180.0 W, size 2.0 cm, frequency 144.00015 MHz, microscopic monitoring, structural changes, hepatocellular tumour model, standing wave ratio, propylene glycol, thermal damages, hepatocellular carcinoma models, radiofrequency hyperthermia, nanoparticle dispersion, tissue alterations, modified tissues, gold shell magnetic nanoparticles, chicken breast tissue, gold‐coated iron oxide nanoparticles, pathology observations, effective penetration depth, histology observations, tissue slices     

Acute upper limb ischemia resulting from cleidocranial dysostosis

A case is reported of a woman with an ischemic arm as a result of damage to the subclavian artery by the clavicular anomaly associated with cleidocranial dysostasis. Only one similar case has been reported previously.     

A Custom VLSI Chip Set for Digital Signal Processing in High-Speed Voiceband Modems

Systems modems intended for use in relatively large private networks are characterized by high performance, reliability and flexibility to support network management, and multiple modes of operation and user features. This paper describes a programmable digital signal processor which is teamed with a 16-bit microprocessor in a dual processor architecture satisfying the requirements of high-speed voiceband systems modems. The architecture of the two custom integrated circuits which form the basis of the signal processor is presented. This processor has novel arithmetic, data structure address generation, and program flow-control capabilities, which result in a high utilization of the arithmetic unit and a low program overhead for housekeeping tasks. Some of these features are illustrated by programming examples.     

A two-phase linear programming methodology for fuzzy multi-objective mixed-model assembly line problem

We develop a fuzzy multi-objective linear programming (FMOLP) model for solving multi-objective mixed-model assembly line problem. In practice, vagueness and imprecision of the goals in this problem make the fuzzy decision-making complicated. The proposed model considers minimizing total utility work, total production rate variation, and total setup cost, using a two-phase linear programming approach. In the first phase, the problem is solved using a max–min approach. The max–min solution not being efficient, in general, we propose a new model in the second phase to maximize a composite satisfaction degree at least as good as the degrees obtained by phase one. To show the effectiveness of the proposed approach, a numerical example is solved and the results are compared with the ones obtained by the fuzzy mixed integer goal programming and weighted additive methods. The computational results show that the proposed FMOLP model achieves lower objective functions as well as higher satisfaction degrees.     

Comparison of chlorination and chloramination practices on microbial inactivation efficiencies within a scaled‐up water distribution network using central composite design

Disinfection practices reduce the incidence of water‐borne diseases but may result in formation of disinfection byproducts (DBPs) in raw water that are reported to be carcinogenic. Central composite design (CCD) was employed in the present study for optimization of disinfectant dose and contact time with the rationale to evaluate if an optimal balance could be achieved between minimal DBPs formation and effective microbial inactivation with either free or combined chlorine in treated water within a lab‐scale prototype network to simulate real water distribution network conditions. After a series of experimental runs based upon design of experiments (DoE) by CCD, dose was found to be the most significant factor (P < 0.01) in determining DBPs formation in both disinfectant’s applications. Where, contact time significantly (P < 0.01) affected bacterial inactivation in chlorination experiments, in contrast, dose was effective in chloramination experiments. Thus, it was concluded that the optimal balance may be achieved in the water networks with the help of multifactorial optimization when disinfectant dose was maintained near 3 mg/L as applied chlorine dose in both disinfection cases, while contact time was 62 and 155 min for chlorine and chloramine, respectively.     

Hydrodynamic characteristics of gas–solid fluidization at high temperature

Effect of temperature on the hydrodynamics of bubbling gas–solid fluidized beds was investigated in this work. Experiments were carried out at different temperatures ranged of 25–600°C and different superficial gas velocities in the range of 0.17–0.78 m/s with sand particles. The time‐position trajectory of particles was obtained by the radioactive particle tracking technique at elevated temperature. These data were used for determination of some hydrodynamic parameters (mean velocity of upward and downward‐moving particles, jump frequency, cycle frequency, and axial/radial diffusivities) which are representative to solids mixing through the bed. It was shown that solids mixing and diffusivity of particles increases by increasing temperature up to around 300°C. However, these parameters decrease by further increasing the temperature to higher than 300°C. This could be attributed to the properties of bubble and emulsion phases. Results of this study indicated that the bubbles grow up to a maximum diameter by increasing the temperature up to 300°C, after which the bubbles become smaller. The results showed that due to the wall effect, there is no significant change in the mean velocity of downward‐moving clusters. In order to explain these trends, surface tension of emulsion between the rising bubble and the emulsion phase was introduced and evaluated in the bubbling fluidized bed. The results showed that surface tension between bubble and emulsion is increased by increasing temperature up to 300°C, however, after that it acts in oppositely.