A high sensitive MEMS capacitive fingerprint sensor using slotted membrane

In this paper a novel single-chip microelectromechanical systems (MEMS) capacitive fingerprint sensor with slotted membrane is developed to improve the sensitivity. The capacitive sensor consists of a thin, flexible membrane and a rigid back plate with air gap. In this study with making slots in upper electrode to decrease the mechanical stiffness of the membrane, using proportional T-shaped protrusion on diaphragm in order to concentrate the force from finger ridges, making holes in lower electrode to reduce the air damping and using low stress material for diaphragm, we have been succeeded to design a novel MEMS fingerprint sensor with high sensitivity compared with the previous works (Sato et al., IEEE Trans Electron Devices 52:1026–1032, 2005; Damghanian and Majlis, 2008 IEEE International Conference on Semiconductor Electronics (ICSE 2008), pp 634–638 2008). The behaviors of the fingerprint sensor with clamped and slotted membranes are analyzed using the finite element method (FEM). The results yield a sensitivity of 1.44 fF/Mpa for the clamped and 3.22 fF/Mpa for the slotted fingerprint sensor with a 50 × 50 μm² diaphragm. The sensitivity of the slotted structure is increased 2.236 times.     

Optimizing the setup of a flatbed color scanner for color measurement using full factorial design

The application of flatbed color scanners for the measurement of color in various industries, especially textile industry, has received a great deal of attention. The initial setup of a scanner and the investigation of factors with a significant effect on scanner outputs are necessary to measure a reliable color using the scanner. In the present study, the setup of a flatbed color scanner was optimized using a full factorial design technique. Three factors, including the scanning position on the glass surface of the scanner (A), cutting size of an image in pixels (B), and bit depth (C), at different levels as input factors, and signal‐to‐noise ratio and variance of the scanned image as the responses were considered for the evaluation of the reliability of the scanner color measurement. The results of analyzing the factorial design indicate that each of the three factors played a significant role in the scanner setup for the color measurement so that factor A demonstrated the most significant impact on the responses.     

NEDA: a low-power high-performance DCT architecture

Conventional distributed arithmetic (DA) is popular in application-specific integrated circuit (ASIC) design, and it features on-chip ROM to achieve high speed and regularity. In this paper, a new DA architecture called NEDA is proposed, aimed at reducing the cost metrics of power and area while maintaining high speed and accuracy in digital signal processing (DSP) applications. Mathematical analysis proves that DA can implement inner product of vectors in the form of two's complement numbers using only additions, followed by a small number of shifts at the final stage. Comparative studies show that NEDA outperforms widely used approaches such as multiply/accumulate (MAC) and DA in many aspects. Being a high-speed architecture free of ROM, multiplication, and subtraction, NEDA can also expose the redundancy existing in the adder array consisting of entries of 0 and 1. A hardware compression scheme is introduced to generate a butterfly structure with minimum number of additions. NEDA-based architectures for 8 /spl times/ 8 discrete cosine transform (DCT) core are presented as an example. Savings exceeding 88% are achieved, when the compression scheme is applied along with NEDA. Finite word-length simulations demonstrate the viability and excellent performance of NEDA.     

Biodegradable Implantable Sensors: Materials Design,Fabrication, and Applications

The ability to monitor diseases, therapies, and their effects on the body is a critical component of modern care and personalized medicine. Real time monitoring can be achieved by analyzing body fluids or by applying sensors on, or alternatively, inside the body. Implantable sensors, however, must be removed. Second removal procedures lead to further tissue damage, which can be a problem in tissues such as those of the central nervous system. The use of biodegradable sensors alleviates these problems since they do not require removal procedures. Recent advances in material science made it possible for all sensor components to be biodegradable. Small size and power of implants, and the limited selection of materials are the main constraints determining the capabilities of the biodegradable device. Thus, the design will be always a challenge exploring a trade-off among these parameters. Despite of the encouraging results illustrating that biodegradable sensors can be as accurate and reliable as commercially available nondegradable ones, biodegradable implantable sensors are still in their infancy. Significant advances made in this area are critically reviewed in this paper, and future prospects are highlighted.     

A novel ceramic membrane reactor system for the continuous enzymatic synthesis of oligosaccharides

The continuous enzymatic production of galactosyl-oligosaccharides (GOS) from lactose as a substrate using a new type of ceramic membrane reactor system was investigated. GOS are non-digestible oligosaccharides and have recently attracted interest as prebiotics. However, the composition of oligosaccharides fraction and the variability in β-glycosidic linkages depend on the enzyme source. In the study presented below, native, physically immobilized, β-galactosidase from Kluyveromyceslactis (EC 3.2.1.23) was used as enzyme to catalyse transgalactosylation reaction to produce GOS, competed against the hydrolysis of lactose into its two component monosaccharides, glucose and galactose. To optimize GOS yielded, process conditions were varied: the average residence time of the enzyme was varied in the range of 13 to 24 min, the trans-membrane pressure (TMP) was in the range of 1 to 2 bar and the initial concentration of substrate was varied from 10 to 30% (w/w). Regarding the conditions investigated here, the maximum oligosaccharide concentration exceeded 38% (w/w) when the average residence time was 24 min, the TMP was 2 bar and an initial lactose concentration of 30% (w/w) was adjusted.     

Comparison of various settling velocity functions and non-Newtonian fluid models in circular secondary clarifiers

An axisymmetric single-phase model that predicts the sedimentation of activated sludge in a circular secondaryclarifier is developed. The k-ɛ turbulence model is used on a two-dimensional, orthogonal and stepwise grid. The concentration equation, which is extended to incorporate the sedimentation of activated sludge in the field of gravity, governs the mass transfer in the clarifier. The computational domain includes the sludge blanket where the viscosity is affected by the rheological behavior of the sludge. Results in case of non-Newtonian fluid model are compared with another numerical approach provided by Lakehal et al. Non-Newtonian fluid models—Bingham, Casson, and Herschel-Bulkley—are used. The influence of settling velocity functions and non-Newtonian models on the flow behavior isinvestigated. Finally, the best models are introduced and the ways that the non-Newtonian model introduces the plastic viscosity are discussed.     

Wireless Power Transmission to a Buried Sensor in Concrete

The feasibility of sending wireless power to a buried sensor antenna within concrete was studied. A receive patch rectenna with 75.8% conversion efficiency was designed for operation at 5.7 GHz. The received DC power at the rectenna was measured within dry and wet concrete samples with various cover thicknesses and air-gaps. For the rectenna buried within 30 mm of the concrete, the received DC power was 10.37 mW, which was about 70% of the received DC power in free-space.     

Catalytic dechlorination of 2,4-dichlorophenol by Ni/Fe nanoparticles in the presence of humic acid: intermediate products and some experimental parameters

The catalytic dechlorination of 2,4-dichlorophenol (2,4-DCP) by Ni/Fe bimetallic nanoparticles in the presence of humic acid (HA) was investigated in order to understand their applicability for in situ remediation of groundwater. 2,4-DCP was catalytically dechlorinated to form the final products – phenol (P) via two intermediates, o-chlorophenol (o-CP) and p-chlorophenol (p-CP). It was demonstrated that the carbon mass balances during the dechlorination were between 84% and 92%, and other carbons were adsorbed on the surface of Ni/Fe bimetallic nanoparticles. The experimental results suggest that HA competed for reaction sites on the Ni/Fe bimetallic nanoparticles with 2,4-DCP, and thus reduced the efficiency and rate of the dechlorination of 2,4-DCP. The catalytic degradation slowed down as the increase of HA in solution, and when HA's concentrations were 0, 10, 20 and 30?mg?L^?1, the maximum concentrations of o-CP were 0.025, 0.041, 0.039 and 0.034?mM in 10, 30, 30 and 30?min, respectively. High Ni content, low initial pH value, high Ni/Fe nanoparticles’ dosage and high temperature favoured the catalytic dechlorination of 2,4-DCP. The experimental results show that no other intermediates were generated besides Cl^?, o-CP, p-CP and P during the catalytic dechlorination of 2,4-DCP.