Method for microfluidic whole-chip temperature measurement using thin-film poly(dimethylsiloxane)/rhodamine B

A novel method is presented for on-chip temperature measurements using a poly(dimethylsiloxane) (PDMS) thin film dissolved with Rhodamine B dye. This thin film is sandwiched between two glass substrates (one of which is 150 microm thick) and bonded to a microchannel molded in a PDMS substrate. Whole-chip (liquid and substrate) temperature measurements can be obtained via fluorescent intensity visualization. For verification purposes, the thin film was tested with a tapered microchannel subjected to Joule heating, with resulting axial temperature gradients comparing well with numerical simulations. Errors induced by the definite film thickness are discussed and accounted for during experimental and analytical analysis. Alternative validation using the traditional in-channel Rhodamine B injection method was also attempted. The thin film has several advantages over traditional methods. First, false intensity readings due to adsorption and absorption of Rhodamine B into PDMS channels are eliminated. Second, whole-chip temperature measurements are possible. Third, separation of working liquid from Rhodamine B dye prevents possible electrophoresis effects.     

Nanoelectronic detection of lectin-carbohydrate interactions using carbon nanotubes

We have used single-walled carbon nanotube field-effect transistor (NTFET) devices to probe the interactions between carbohydrates and their recognition proteins called lectins. These interactions are involved in a wide range of biological processes, such as cell-cell recognition, cell-matrix interaction as well as viral and bacterial infections. In our experiments, NTFETs were functionalized noncovalently with porphyrin-based glycoconjugates synthesized using "click" azide-alkyne chemistry, and change in electrical conductance was measured upon specific binding of two bacterial lectins that present different carbohydrate preference, namely PA-IL, PA-IIL from Pseudomonas aeruginosa and a plant lectin Concanavalin A. However, no significant change in the device characteristics was observed when the devices were exposed to other lectins with different specificity. Detection of PA-IL binding to galactosylated NTFETs was highly sensitive (2 nM) with a measured dissociation constant (K(d) = 6.8 μM) corresponding to literature data. Fluorescence microscopy, atomic force microscopy, UV-vis-NIR spectroscopy, and several control measurements confirmed the NTFET response to selective interactions between carbohydrates and lectins.     

A model for measuring complexity of automated and hybrid assembly systems

The demand for delivering product variety has been increasing. Increased product variety caused by product customization, personalization, evolution and changes in their manufacturing systems. Variety allows manufacturers to satisfy a wide range of customer requirements, but it can also be a major contributing factor to increased complexity of assembly. Complexity is generally believed to be one of the main causes of the present challenges in manufacturing systems such as lengthy and costly design processes, higher life cycle costs and the existence of numerous failure modes. Complex assembly systems are costly to implement, run, control and maintain. Assessing complexity of assembly helps guides designers in creating assembly-oriented product designs and following steps to reduce and manage sources of assembly complexity. On the other hand, reducing complexity of assembly helps lower assembly cost and time, improves productivity and quality and increases profitability and competitiveness. The complexity of assembly should be assessed by considering both products and their assembly systems. In this paper, a structural classification coding scheme has been used to measure assembly systems complexity. It considers the inherent structural complexity of typical assembly equipment. The derived assembly systems complexity accounts for the number, diversity and information content within each class of the assembly system modules. A domestic appliance drive assembly system is used to demonstrate the use of the classification code to calculate the assembly system complexity. The developed complexity metrics can be used by designers as decision support tools to compare and rationalize various automated assembly systems alternatives and select the design that meets the requirements while reducing potential assembly complexity and associated cost.     

A rotary flange forming process on the lathe using a ball-shaped tool

Flanging of tube ends is carried out using casting or assembly joining, which have drawbacks due to improper strength, defect generation or low efficiency. In this work, flange forming of Al tubes was performed on the lathe utilizing a ball-shaped tool attached to the lathe carriage, and fed outwards radially while the specimen clamped to the lathe chuck and rotated. Tubular specimens, were rotated at 500 rpm, and the tool feed was 0.314 mm/rev. Ball diameter (D_ball) of 12.8 mm was fixed, while the tool advance distance (T_a) at the start of flanging was 0.125, 0.25, 0.5, 0.625D_ball. Oil was used as a lubricant. Results showed that the radial flanging force was increased as t₀ and T_a increased. An approximate contact area calculation was presented and the calculated loads were in agreement with the experimentally obtained ones. Relatively large flanging ratios (FR) were obtained and those were found to increase as t₀ decreases and T_a increases. Maximum thinning was observed at the flange edge followed by an increase in thickness towards the area between the tube and flange. Surface hardness increased as t₀ increased.     

Anomalies of electrical properties of Sm-cuprate oxides substituted with yttrium and iron oxides at low temperatures

Samples of Sm_2-xR_xCuO₄ (R=Y and Fe), for x=0.0 and 0.05, were prepared by standard solid-state reactions. The lattice parameters of the single-phase cuprates increased for the altered samples. The samples were studied by differential scanning calorimetry, scanning electron microscopy, electrical resistivity, and thermoelectric power measurements. The effect of substitution was found to increase compound stability, decrease the electrical resistivity, and change the sign of the thermoelectric power. The anisotropy field due to apical oxygen in the unaltered sample was not found.     

Free convection in inclined air layers heated from above

An experimental investigation of steady-state natural convection heat transfer was carried out in finite rectangular air layers heated from above. Two different aspect ratios, namely A = 20 and 80, and perfectly conducting boundary conditions on the end walls were used. The angle of inclination was varied from Φ = 0 (heated from below) to Φ = 180° (heated from above). A total of 226 test points were taken for heat transfer measurements in air layers heated from above at four different orientations in the range 120 ? Φ ? 180° for Rayleigh numbers between 10² and 2 × 10⁶. Additional test points have been carried out to show the effect of the angle of tilt in the range O ? Φ ? 180° on the average Nusselt number for fixed values of the Rayleigh number. Local measurements of the Nusselt number over discrete portions of the air layer are reported to show the Nusselt number distribution over different flow regimes.     

Modulating the Ferromagnet/Molecule Spin Hybridization Using an Artificial Magnetoelectric

Spin‐polarized charge transfer at the interface between a ferromagnetic (FM) metal and a molecule can lead to ferromagnetic coupling and to a high spin polarization at room temperature. The magnetic properties of these interfaces can not only alter those of the ferromagnet but can also stabilize molecular spin chains with interesting opportunities toward quantum computing. With the aim to enhance an organic spintronic device's functionality, external control over this spin polarization may thus be achieved by altering the ferromagnet/molecule interface's magnetic properties. To do so, the magnetoelectric properties of an underlying ferroelectric/ferromagnetic interface are utilized. Switching the ferroelectric polarization state of a PbZr_0.2Ti_0.8O₃ (PZT) bottom layer within a PZT/Co/FePc‐based (Pc ‐ phthalocyanine) device alters the X‐ray magnetic circular dichroism of the Fe site within the phthalocyanine molecular top layer. Thus, how to electrically alter the magnetic properties of an interface with high spin polarization at room temperature is demonstrated. This expands electrical control over spin‐polarized FM/molecule interfaces, which is first demonstrated using ferroelectric molecules, to all molecular classes.     

Optimal business process deployment cost in cloud resources

Cloud computing is the fastest emerging technology that proposes several resources under various pricing strategies that are specified based on temporal constraints. The main aim of cloud computing is to enhance the performance level and minimize operating costs. Thus, organizations looking towards optimizing their spending on IT infrastructure find such pricing strategies very attractive, especially, to deploy their business process models. However, discovering the optimal deployment cost of a business process in cloud resources proposed under various pricing strategies becomes a highly challenging problem. So, the objective of the present paper is to present an approach that assists business process designers in finding an optimal assignment or scheduling based on the variety of pricing strategies. We use linear programming models with an objective function under a set of constraints. Besides, we propose an extension of the famous cloud simulator provided in the market, CloudSim, to simulate the cloud resources consumed to deploy a business process model. The experimental results show the feasibility, effectiveness, and performance of our approach.

     

A generalized multiclass histogram thresholding approach based on mixture modelling

This paper presents a new approach to multi-class thresholding-based segmentation. It considerably improves existing thresholding methods by efficiently modeling non-Gaussian and multi-modal class-conditional distributions using mixtures of generalized Gaussian distributions (MoGG). The proposed approach seamlessly: (1) extends the standard Otsu's method to arbitrary numbers of thresholds and (2) extends the Kittler and Illingworth minimum error thresholding to non-Gaussian and multi-modal class-conditional data. MoGGs enable efficient representation of heavy-tailed data and multi-modal histograms with flat or sharply shaped peaks. Experiments on synthetic data and real-world image segmentation show the performance of the proposed approach with comparison to recent state-of-the-art techniques.