Yousef Haik

Numerical simulation of biomagnetic fluid downstream an eccentric stenotic orifice

Biomagnetic fluid dynamics is the study of the interaction of biological fluids with an applied steady magnetic field. The composition of the biological fluid is considered nonconducting; however, it has magnetic moment. The magnetic moment of the biological fluid can be enhanced by tagging superparamagnetic particles. Several biomedical applications recently developed utilize the magnetic labeling of cellular components. In this paper, the biomagnetic fluid downstream an eccentric stenotic orifice is considered. An external magnetic field is applied at different locations down stream the stenotic orifice. It is found that based on the location of the magnetic field, the reattachment point downstream the stenotic orifice changes; it is also found that the shear stress will be affected based on the magnetic field location. Major changes in the flow pattern have been also observed based on the magnetic field strength.

Physically synthesized Ni-Cu nanoparticles for magnetic hyperthermia

BackgroundIn this paper, a physical method to prepare copper-nickel alloy particles in the sub-micron range for possible self controlled magnetic hyperthermia treatment of cancer is described. It is reported that an increase in tumor temperature decreases the tumor resistance to chemo- and radiation therapies. Self controlled heating at the tumor site to avoid spot heating is managed by controlling the Curie temperature of the magnetic particles. The process described in this paper to produce the nanomagnetic particles allows for a large scale production of these particles.MethodsThe process used here is mainly composed of melting of the Cu-Ni mixture and ball milling of the resulted bulk alloy. Both mechanical abrasion and continuous grinding were used to break down the bulk amount into the desired particle size.ResultsIt was found that the desired alloy is composed of 71% nickel and 29% copper by weight. It was observed that the coarse sand-grinded powder has a Curie temperature of 345 K and the fine ball-milled powder shows a temperature of 319 K – 320 K.ConclusionSelf regulating magnetic hyperthermia can be achieved by synthesizing nanomagnetic particles with desired Curie temperature. In this study the desired range of Curie temperatures was obtained by combination of melting and ball milling of nickel-copper alloy.

A biocompatible magnetic film: synthesis and characterization.

BackgroundBiotechnology applications of magnetic gels include biosensors, targeted drug delivery, artificial muscles and magnetic buckles. These gels are produced by incorporating magnetic materials in the polymer composites.MethodsA biocompatible magnetic gel film has been synthesized using polyvinyl alcohol. The magnetic gel was dried to generate a biocompatible magnetic film. Nanosized iron oxide particles (γ-Fe2O3, ~7 nm) have been used to produce the magnetic gel.ResultsThe surface morphology and magnetic properties of the gel films were studied. The iron oxide particles are superparamagnetic and the gel film also showed superparamagnetic behavior.ConclusionMagnetic gel made out of crosslinked magnetic nanoparticles in the polymer network was found to be stable and possess the magnetic properties of the nanoparticles.

Microscopic flow visualization system for fluids in magnetic field

Abstract A flow visualization technique has been developed to allow investigation of micron-scale flow behaviors by coupling the techniques of laser-induced fluorescence (LIF) and particle imaging velocimetry (PIV), and adapting them to the micron scales. In this paper, the flow studies have been performed using image analysis of fluorescent magnetic microspheres of 3xa0μm average diameter suspended in fluid and subjected to a magnetic field.

NANOMAGNETICS IN BIOTECHNOLOGY

Applications of nanomagnetic particles in cell separation and magnetic hyperthermia are presented here. In general, biological cells are weakly paramagnetic or diamagnetic. Therefore, to enhance the magnetic susceptibility of the biological cells to interact with an applied magnetic field, nanoto micron-sized magnetic particles are tagged to the biological cells. Nano-size magnetic particles are produced in-house for various biomagnetic applications.

FABRICATION OF ARRAY MICROSTRUCTURES USING SERIAL AND PARALLEL LOCALIZED ELECTRODEPOSITION

To add to the development efforts in enhancing the capabilities of localized electrodeposition (LED) fabrication technique, this paper presents serial and parallel deposition algorithms to fabricate array microstructures. Such arrays can be implemented as microsensors in neural recording applications or as antenna arrays in ultra high frequency applications. Also, magnetic tip microarrays for tissue engineering can be realized. In the case of serial fabrication, an array of high aspect ratio microstructures is realized using the conventional single-tip microelectrode while implementing a multistep fabrication algorithm. In this algorithm, the fabricated microstructure elements within the array are realized one at a time. In the parallel deposition algorithm, the array is realized using a multitip array microelectrode while implementing a single step fabrication algorithm. In this algorithm, the microstructure elements within the array are fabricated simultaneously. The proposed algorithms are compared through a demonstration of fabricated array microstructures.

Development of Nano-Microtechnology and Biomedical Applications

Blood, air and water are not only most abundant but also the most important fluids on the earth. Each adult human carries almost a gallon of blood every moment. This paper concerns with the treatment of the blood and discusses in particular the blood cell separation (fluids engineering) and the safe elevation of the body temperature (thermal engineering). Unlike air and water the blood is a biological fluid. Therefore it comes with the complexity of blood composition and disorder of the blood affecting human life and health. This study presents applications of electro-magnetic field on nanomagnetic particles that attach to the blood cells in creating complex fluid dynamic cell separation from the whole blood and creating complex thermal heating, magnetic hyperthermia, for potential use in cancer treatment. In general, biological cells are weak paramagnetic or diamagnetic. Therefore nano-microtechnologies are developed to attach the nanoparticles to the selected cells and to enhance the magnetic susceptibility of the cells to interact with an applied magnetic field. The paper demonstrates that nano to micron size magnetic particles are tagged to the biological cells.Copyright

Fabrication of NdFeB Thin Film and Its Application in MEMS

The paper measures the magnetic properties of NdFeB thin films developed under the effects of magnetic field. The samples exhibited a larger residual inductance, saturation magnetization and energy product than those treated without field or with weaker field. Magnetic MEMS was introduced with application of the NdFeB film to micro device such as pumps and gear transmission system.Copyright

System identification for a lumped heat exchanger using the extended information filter

In this study a new Extended Information Filter (EIF) algorithm is applied to compute the heat transfer parameters for lumped heat exchanger. Many industrial applications depend on the prediction of the heat exchanger parameters. This algorithm produces an accurate prediction of the operating states and parameters. A state variable model is derived from the empirical correlation of the lumped heat exchanger. The derived system is nonlinear and stochastic. The problem of estimating the state variables and parameters is considered in the presence of random disturbance and measurement noise. The EIF is then used to produce an optimal estimate of the state and parameters of the heat exchanger. The result obtained by using EIF were compared to the results obtained by using EIF were compared to the result obtained using EKF and found that the estimation of dynamic nonlinear systems, is best carried out using the EIF rather than the EKF.