Hybrid Paper–Plastic Microchip for Flexible and High‐Performance Point‐of‐Care Diagnostics

A low‐cost and easy‐to‐fabricate microchip remains a key challenge for the development of true point‐of‐care (POC) diagnostics. Cellulose paper and plastic are thin, light, flexible, and abundant raw materials, which make them excellent substrates for mass production of POC devices. Herein, a hybrid paper–plastic microchip (PPMC) is developed, which can be used for both single and multiplexed detection of different targets, providing flexibility in the design and fabrication of the microchip. The developed PPMC with printed electronics is evaluated for sensitive and reliable detection of a broad range of targets, such as liver and colon cancer protein biomarkers, intact Zika virus, and human papillomavirus nucleic acid amplicons. The presented approach allows a highly specific detection of the tested targets with detection limits as low as 10² ng mL^?1 for protein biomarkers, 10³ particle per milliliter for virus particles, and 10² copies per microliter for a target nucleic acid. This approach can potentially be considered for the development of inexpensive and stable POC microchip diagnostics and is suitable for the detection of a wide range of microbial infections and cancer biomarkers.     

Experimental Comparison of the Effects of Nanometric and Micrometric Particulates on the Tensile Properties and Fracture Behavior of Al Composites at Room and Elevated Temperatures

This article studies the influence of nanometric (n-SiC_p) and micrometric-scale SiC particulates (μ-SiC_p) on the tensile properties of the Al 7075 alloy. The unreinforced Al and its composites were synthesized using the powder metallurgy (P/M) route and were tested uniaxially in tension at both room and elevated temperatures. Aging behavior was studied to observe any effect of the reinforcement on the aging kinetics and hardness of the composites. X-ray diffraction was performed to determine the crystal structures of the raw materials and any reaction phase formed in the composites. The n-SiC_p were not dispersed uniformly in the Al matrix and clustered mainly at the grain boundaries. The stiffness of the composites increased and the ductility decreased with an increase in the volume fraction of the n-SiC_p. The n-SiC_p proved to be a better reinforcement than the traditional μ-SiC_p in terms of imparting higher ductility to the composite. Fractography and microscopy using optical, scanning electron, and transmission electron microscopes were performed for failure and microstructural analysis of all the materials. At room temperature, the fracture altered from ductile in the unreinforced Al to brittle in the composites. At an elevated temperature, the fracture mechanism transformed from brittle to ductile rupture in the composites.     

Copolymerization of carbon monoxide with exo‐methylenecycloalkane and dienes: synthesis of functionalized aliphatic polyketones

Synthesis of functional aliphatic polyketones was achieved by co‐ and terpolymerization of the strained exo‐methylenecycloalkane, methylenecyclopropane (MCP), and also the dienes 1,5‐hexadiene, 1,7‐octadiene and 1,6‐heptadien‐4‐ol, with carbon monoxide and propene, using the dicationic palladium(II) phosphine complex [Pd(dppp) (NCCH₃)₂](BF₄)₂ (I) (dppp is 1,3‐bis(diphenyl‐phosphino)propane) as the catalyst precursor. The resulting MCP/CO copolymer contains both ring‐opened and cyclic microstructures. Ring‐opening copolymerization yields exo‐methylene functionalized polyketone. In contrast to hexadiene/carbon monoxide copolymer (Hx/CO), no ring structures were observed in the alternating octadiene/carbon monoxide (Oc/CO) and heptadien‐4‐ol/carbon monoxide (Hp‐ol/CO) copolymers. The remaining double bonds were left intact to yield polymers with olefinic functionalities in the side chains. © 2001 Society of Chemical Industry     

Interface structure of diffusion bonded duplex stainless steel and medium carbon steel couple

Diffusion bonding of duplex stainless steel to medium carbon steel was carried out with different temperatures for sound bonds. In the bonding process, relatively intermediate temperatures such as 750, 800, 850 and 900 °C were used with a bonding time of 30 min. In this study, microstructural changes and mechanical properties in the interface region of duplex stainless steel and medium carbon steel couples were determined. The results showed that, in interface region, Cr₂₃C₆ was formed on the stainless steel side, while ferrite formation was observed on the carbon steel side as a result of mutual diffusion of C and Cr.     

Effects of environmental factors on the adhesion and durability characteristics of epoxy-bonded concrete prisms

This work is concerned with the effects of environmental factors on the adhesion and durability characteristics of epoxy-bonded concrete prisms. The results indicate that the presence of liquid water at the interfacial zone during the epoxy injection process disrupts the initial bond configurations. The freezing and thawing up to about 40 cycles do not have a significant effect on the bond stability. An adequate degree of chemical stability is maintained in the bond line by the epoxy adhesives after 120 days of exposure to corrosive environments such as MgSO₄ and MgCl₂. However, there is a pronounced effect of these chemical substances on the concrete strength. The load-bearing capacity of epoxy-bonded concrete prisms decreases with increasing temperature. Despite this fact, the EP3-bonded concrete prisms give relatively high joint strengths at temperatures up to 100 °C.     

Bipolar resistive switching in p-type Co3O4 nanosheets prepared by electrochemical deposition

Metal oxide nanosheets have potential applications in novel nanoelectronics as nanocrystal building blocks. In this work, the devices with a structure of Au/p-type Co₃O₄ nanosheets/indium tin oxide/glass having bipolar resistive switching characteristics were successfully fabricated. The experimental results demonstrate that the device have stable high/low resistance ratio that is greater than 25, endurance performance more than 200 cycles, and data retention more than 10,000 s. Such a superior performance of the as-fabricated device could be explained by the bulk film and Co₃O₄/indium tin oxide glass substrate interface effect.     

A parametric study on the factors affecting the froth floatation of Jordanian tar sand utilizing a fluidized bed floatator

Different parameters affecting the behavior of froth flotation of Jordanian tar sand, obtained from the Dead Sea area, were studied. This study was performed in a modified fluidized bed floatator. The effects of the addition of a flotation agent, NaOH, temperature and flotation time on the beneficiation of bitumen in the froth were investigated. It was found that the beneficiation factor in the froth increased with the increase of temperature and flotation time. However, the amount of base (NaOH) and the flotation agent were found to have a negative effect on that factor. A regression model based on a full factorial experimental design results was obtained with a significant correlation coefficient. The optimum beneficiation factor was found to be 7.2 and the bitumen content in the froth was found to be 79% in the froth, which was obtained at 0.2 gNaOH/L, zero agent, 80 °C, and 30 min.     

A quasi-static analysis for a class of induced-current EIT systems using discrete coils

A discrete coil EIT system is investigated for the general case of an eccentric circular inhomogeneity. The solution methodology of the forward problem of this system is explained. An optimization procedure using this forward problem solution is developed to find optimum currents that maximize the distinguishability. For an eccentric inhomogeneity problem, it is shown that the coil currents can be optimized to focus the current density in a region of interest. Optimum coil currents under limited peak coil currents constraint and limited total power constraint are obtained. Representative examples that demonstrate the performance of the system are presented.     

Communication—Processor Tradeoffs in a Limited Resources PRAM

We consider a simple restriction of the PRAM model (called PPRAM), where the input is arbitrarily partitioned between a fixed set of p processors and the shared memory is restricted to m cells. This model allows for investigation of the tradeoffs/ bottlenecks with respect to the communication bandwidth (modeled by the shared memory size m ) and the number of processors p . The model is quite simple and allows the design of optimal algorithms without losing the effect of communication bottlenecks. We have focused on the PPRAM complexity of problems that have $\tilde{O}$ (n) sequential solutions (where n is the input size), and where m ≤ p ≤ n . We show essentially tight time bounds (up to logarithmic factors) for several problems in this model such as summing, Boolean threshold, routing, integer sorting, list reversal and k -selection. We get typically two sorts of complexity behaviors for these problems: One type is $\tilde{O}$ (n/p + p/m) , which means that the time scales with the number of processors and with memory size (in appropriate ranges) but not with both. The other is $\tilde{O}$ (n/m) , which means that the running time does not scale with p and reflects a communication bottleneck (as long as m < p ). We are not aware of any problem whose complexity scales with both p and m (e.g. $O(n/\sqrt{m \cdot p})$ ). This might explain why in actual implementations one often fails to get p -scalability for p close to n .