Mechanical Engineering

A nanoporous polymer thin film has been developed as a potential platform for drug delivery. The film was fabricated by a light-induced polymerization process in which non-reactive solvent was first separated from photopolymer (dipentaerythritol penta-/hexa-acrylate as the monomer) and then removed from polymer via evaporation, yielding pores with diameters between 20 and 40 nm. Loading and release of Rhodamine B (drug model molecules) on both porous and non-porous thin films proved that nanopores enhanced the film's effectiveness in encapsulating and releasing the drug model molecules, which was attributed to the high surface-to-volume ratio of nanoporous film. Ultrasound-enhanced cumulative and pulsatile release revealed the advantages of ultrasound in controlled drug delivery.

Heat transfer coefficients were measured for forced convection refrigerant mixture (R-407C) flow in meso-scale heat exchangers enhanced by subsonic vibration. Flow in three horizontal meso-channels (ID 1.0 mm, 2.0 mm, and 4 mm), and a length of 60 mm for subcooled and saturated boiling conditions are reported in this study. Experiments were conducted at heat fluxes of 2 and 11 kW/m 2 for subcooled boiling, and 15 and 29 kW/m 2 for saturated boiling. The mass flow rate was varied from 0.45 to 1.85 kg/min. The frequency was varied, freq=0-70 Hz. An experimental setup composed of heating elements provided heat flux variations in the meso-channels and excitation elements were attached to the side of the channels to produce the subsonic vibrations. The heat transfer coefficient was found to be dependent on both the heat flux as well as mass flux levels. Results show that subsonic vibration enhanced the heat transfer performance over that of non enhanced meso-channels by 8% as compared to regular flow convective boiling process.

Demand for high-strength alloys in aerospace, marine and off-shore industries has grown significantly over the last decades, primarily thanks to their high strength, light weight as well as good fatigue and corrosion-resistance properties. However, those materials are extremely difficult to machine with conventional machining methods. Hot machining is an alternative technique, used by many researchers for cutting of hard-to-cut materials in turning and milling operations. In this assisted machining technique, an external heat source is used to reduce shear strength of the machined workpiece and enhancing material removal rate of such alloys.

Heat transfer coefficients were measured for forced convection refrigerant mixture (R-407C) flow in micro channels enhanced by acoustics vibration. Flow in horizontal micro channels (ID 100.0 m), and a length of 50 mm for subcooled and saturated boiling conditions are reported in this study. Experiments were conducted at a heat flux of 6 kW/m 2 for subcooled boiling; saturated boiling was carried at heat fluxes of 15 and 29 kW/m 2 . The mass flow rate was varied from 0.45 to 1.85 kg/min. The frequency was varied, freq= 5, 10, and 15 kHz. An experimental setup composed of heating elements provided heat flux variations in the micro channels and excitation elements were attached to the side of the channels to produce the acoustics vibrations. The heat transfer coefficient was found to be dependent on both the heat flux as well as mass flux levels. Results show that acoustics vibration enhanced the heat transfer performance by 21% as compared to regular flow convective boiling process.

Measurements were done for the heat transfer coefficients h in forced convection refrigerant mixture (R-407C) flow within micro channels enhanced by impulse acoustic vibration. Flow in horizontal micro channels (ID 100.0 length of 50 mm for subcooled and saturated boiling conditions are reported in this study. The heat flux was ranged from 6 kW/m 2 for subcooled boiling; saturated boiling was carried at heat fluxes of 15 and 29 kW/m 2 . The mass flow rate varied from 0.45 to 1.85 kg/min. The frequency was maintained at a constant value of 20 kHz. The impulse was varied in three ranges of 20, 40, and 60 dBs. An experimental setup composed of heating elements provided heat flux variations in the micro channels and excitation elements attached to the side of the channels to produce the impulse acoustic vibrations. The heat transfer coefficient found to be dependent on both the heat flux as well as mass flux levels. Results show that impulse acoustic vibration enhanced the heat transfer performance by 12% as compared to regular flow convective boiling process.

In this study, a 2-D MHD free convection incompressible electrically induced boundary layer analysis on a water/nano-fluidic mixture. The ODE solution is numerically analyzed with a Runge-Kutta model as the thermophysical properties on a magnetic variation as well as temperature ranges of buoyancy effects on the T and V profiles and the wall force friction on the flow is also studied. The temperature and velocity gradients have a significant differential change is been observed in this study.

Cost-effective, high-performance diagnostic instruments are vital to providing the society with accessible, affordable, and high-quality healthcare. Here we present an integrated, ''microfluidic drifting'' based flow cytometry chip as a potential inexpensive, fast, and reliable diagnostic tool. It is capable of analyzing human blood for cell counting and diagnosis of diseases. Our device achieves a throughput of 3754 events/s. Calibration with Flow-Check calibration beads indicated good congruency with a commercially available benchtop flow cytometer. Moreover, subjection to a stringent 8-peak rainbow calibration particle test demonstrated its ability to perform high-resolution immunological studies with separation resolution of 4.28 between the two dimmest fluorescent populations. Counting accuracy at different polystyrene bead concentrations showed strong correlation (r = 0.9991) with hemocytometer results. Finally, reliable quantification of CD4+ cells in healthy human blood via staining with monoclonal antibodies was demonstrated. These results demonstrate the potential of our microfluidic flow cytometry chip as an inexpensive yet high-performance point-of-care device for mobile medicine.

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This paper deals with the effect of changing turning parameters on the cutting forces while machining AISI 1020 steel. Experimental results reveal that the increase in depth of cut (d) influenced the cutting forces more when compared to changing the feed rate (f) and cutting speed (v). Also, within the selected range of variables, an optimum material removal rate (MRR) is also recommended. (Ahmed N, Atta R, Shariff YM. Effect of changing turning parameters on the cutting forces. Life Sci J 2014;11(10s):25-32). (ISSN:1097-8135). http://www.lifesciencesite.com . 5

Abstract: This paper deals with the effect of changing turning parameters on the cutting forces while machining AISI 1020 steel. Experimental results reveal that the increase in depth of cut (d) influenced the cutting forces more when compared to changing the feed rate (f) and cutting speed (v). Also, within the selected range of variables, an optimum material removal rate (MRR) is also recommended.

Associate Editor Tingrui Pan oversaw the review of this article. Abstract—Cost-effective, high-performance diagnostic instru-ments are vital to providing the society with accessible, affordable, and high-quality healthcare. Here we present an integrated, ‘‘microfluidic drifting’ ’ based flow cytometry chip as a potential inexpensive, fast, and reliable diagnostic tool. It is capable of analyzing human blood for cell counting and diagnosis of diseases. Our device achieves a throughput of ~3754 events/s. Calibration with Flow-Check calibration beads indicated good congruency with a commercially available benchtop flow cytometer. Moreover, subjection to a stringent 8-peak rainbow calibration particle test demon-strated its ability to perform high-resolution immunological studies with separation resolution of 4.28 between the two dimmest fluorescent populations. Counting accuracy at different polystyrene bead concentrations showed strong correlation (r = 0.9991) with hemocytometer resul...

Household and personal items and sums in checking accounts are usually not included in this type of trust, but are instead left to be disposed of by will or an intestacy statute. 2. The contract may be void if it is governed by the law of a place which has a strong public policy condemning postnuptial contracts which reduce postmortem statutory rights of the surviving spouse. The contract probably would be void in Oklahoma.

A supersonic expansion cannot be achieved within a convergent-divergent nozzle if the flow velocity does not reach that of the sound at the throat. The computation of the flow field characteristics at the throat is thus essential to the nozzle developed thrust value and therefore to the aircraft or rocket it propels. Several approaches were developed in order to describe the transonic expansion, which takes place through the throat of a De-Laval convergent-divergent nozzle. They all allow reaching good results but showing a major shortcoming represented by their inability to describe the transonic flow field for nozzles having a small throat radius. The approach initially developed by Kliegel & Levine uses the velocity series development in terms of the normalized throat radius added to unity instead of solely the normalized throat radius or the traditional small disturbances theory approach. The present investigation carries out the application of these three approaches for different throat radiuses of curvature. The method using the normalized throat radius added to unity shows better results when applied to geometries integrating small throat radiuses.

A comparatively simple method for obtaining wall contours of supersonic nozzles of arbitrary exit cross sections from readily determined axisymmetric flows is presented. An initial axisymmetric flowfield is calculated using the method of characteristics in two dimensions from which the desired three-dimensional shape may be generated by specifying the appropriate cross section at the streamwise station giving the required overall nozzle length and exit Mach number. The describing points on the perimeter of this section are traced along corresponding streamlines back  to the throat. The stream sheets formed by these streamlines then define the new nozzle contour. Elliptical and two-dimensional wedge-shaped nozzles are designed using this approach, and comparisons are reported between detailed finite-difference flowfield predictions and experimental measurement.

Engineering education plays a very important role in the social and economic development of a nation as well as its standing in the world.  During the 19th and 20th centuries, engineering “disintegrated” into specific disciplines.  The 21st century will instead be a time of integration, as the various sub-disciplines of the sciences and engineering converge. Moreover, the emergence of the world economy has led to a real need to develop a global awareness in the minds of today’s engineering students. They need to recognize that being bright and technically sound and motivated is not enough.  They must also have skills to defend and sell technical ideas as well as excellent oral and written communication skills for a successful career.  Universities must provide guidance and a curriculum making the achievement of this goal possible for all students.  They must also have to continuously develop innovative approaches to education delivery and training as well as offer knowledge in a motivating way and insure retention.  The actual paper reviews some aspects of the traditional system of engineering education particularly in the North African countries as well as in some European countries (France and Germany).  It also presents the emerging trends in engineering education and discusses the key characteristics of the 21st century engineer.  Instructional methods and quality assessment and certification are also reviewed.

Wear of components is often a critical factor influencing the product service life. Wear prediction is therefore an important part of engineering. The wear simulation approach with commercial finite element (FE) software ANSYS is presented in this paper. A modelling and simulation procedure is proposed and used with the linear wear law and the Euler integration scheme. Good care, however, must be taken to assure model validity and numerical solution convergence. A spherical pin-on-disc unlubricated steel contact was analysed both experimentally and with FEM, and the Lim and Ashby wear map was used to identify the wear mechanism. It was shown that the FEA wear simulation results of a given geometry and loading can be treated on the basis of wear coefficient−sliding distance change equivalence. The finite element software ANSYS is well suited for the solving of contact problems as well as the wear simulation. The actual scatter of the wear coefficient being within the limits of ±40–60% led to considerable deviation of wear simulation results. These results must therefore be evaluated on a relative scale to compare different design options.

This work focuses on the thickness scalability of traveling heater method (THM) grown CdZnTe crystals to produce large volume detectors with optimized spectroscopic performance. To meet this challenge, we have tuned both our THM growth process, to grow 75 mm diameter ingots, and our postgrowth annealing process. We have increased the thickness of our sliced wafers from 6 to 12 and 18 mm allowing the production of 10 and 15 mm thick detectors. As the detectors' thickness is scaled up, the energy resolution of both types, as pseudo-Frisch grid and pixelated monolithic detectors showed no degradation indicating improved materials uniformity and transport properties.

New results on the effects of small-scale defects on the charge-carrier transport in singlecrystal CdZnTe (CZT) material were produced. We conducted detailed studies of the role of Te inclusions in CZT by employing a highty collimated synchrotron x-ray radiation source available at Brookhaven's National Synchrotron Light Source (NSLS). We were able to induce polarization effects by irradiating specific areas with the detector. These measurements allowed the first quantitative comparison between areas that are free of Te inclusions and those with a relatively high concentration of inclusions. The results of these polarbtion studies will be reported.

The spectral response of several crystals grown by the Traveling Heater Method (THM) were investigated. An energy resolution of 0.98% for a Pseudo Frisch-Grid of 4 4 9 mm 3 and 2.1% FWHM for a coplanar-grid of size 11 11 5 mm 3 were measured using 137 Cs-662 keV. In addition a 4% FWHM at 122 keV has also been measured on 20 20 5 mm 3 monolithic pixellated devices. The material shows great potential toward producing large-volume detectors with spectral performance that meets the requirement for high-resolution gamma-ray spectroscopy.

High-performance semi-insulating single crystals of n-type Cd 0 9 Zn 0 1 Te (CZT) were grown using the traveling heater method (THM). X-ray and -ray detector configurations fabricated from this material have a room-temperature mean energy resolution of 4.3% FWHM for a 57 Co source (122 keV) and uniform pixel-to-pixel response on monolithic 20 20 5 mm 3 pixellated detectors. Energy resolution of 1% FWHM for 137 Cs (662 keV) has been measured on virtual Frisch-grid 4 4 11 mm 3 devices useful for homeland security applications. Additional characterization techniques including mobility-lifetime measurements, infrared microscopy, X-ray topography, and OPTICAL Deep Level Transient Spectroscopy (ODLTS) have demonstrated the superior quality of this THM CZT.