Analysis of some paper handling problems by a three-dimensional nonlinear finite element algorithm

A three-dimensional nonlinear finite element algorithm was developed to predict the change in paper topology as well as the wrinkle performance of the roll feeding systems. The initial shape of the thin plate to be analyzed can be perfectly flat or wavy. The roll system can be of any arbitrary configuration with manufacturing tolerance included. The algorithm described here uses the total Lagrange formulation with Piola-Kirchhoff stress and Green-Lagrange strain. Gap elements are used to simulate the physical significance of the paper supports. Quasistatic solutions at different time intervals are calculated. The change in topology and the locations of predicted wrinkles are found to agree with experiments.     

On a new class of finite dimensional estimation algebras

We introduce a new class of solvable finite dimensional estimation algebras that contains both the linear and the Bene cases. The condition for finite dimensionality is expressed in terms of two matrices. They play an important role in understanding the structure of estimation algebras.     

Structural Analysis of Mitochondrial Dynamics—From Cardiomyocytes to Osteoblasts: A Critical Review

Mitochondria play a crucial role in cell physiology and pathophysiology. In this context, mitochondrial dynamics and, subsequently, mitochondrial ultrastructure have increasingly become hot topics in modern research, with a focus on mitochondrial fission and fusion. Thus, the dynamics of mitochondria in several diseases have been intensively investigated, especially with a view to developing new promising treatment options. However, the majority of recent studies are performed in highly energy-dependent tissues, such as cardiac, hepatic, and neuronal tissues. In contrast, publications on mitochondrial dynamics from the orthopedic or trauma fields are quite rare, even if there are common cellular mechanisms in cardiovascular and bone tissue, especially regarding bone infection. The present report summarizes the spectrum of mitochondrial alterations in the cardiovascular system and compares it to the state of knowledge in the musculoskeletal system. The present paper summarizes recent knowledge regarding mitochondrial dynamics and gives a short, but not exhaustive, overview of its regulation via fission and fusion. Furthermore, the article highlights hypoxia and its accompanying increased mitochondrial fission as a possible link between cardiac ischemia and inflammatory diseases of the bone, such as osteomyelitis. This opens new innovative perspectives not only for the understanding of cellular pathomechanisms in osteomyelitis but also for potential new treatment options.     

Depth from Refraction Using a Transparent Medium with Unknown Pose and Refractive Index

In this paper, we introduce a novel method for depth acquisition based on refraction of light. A scene is captured directly by a camera and by placing a transparent medium between the scene and the camera. A depth map of the scene is then recovered from the displacements of scene points in the images. Unlike other existing depth from refraction methods, our method does not require prior knowledge of the pose and refractive index of the transparent medium, but instead can recover them directly from the input images. By analyzing the displacements of corresponding scene points in the images, we derive closed form solutions for recovering the pose of the transparent medium and develop an iterative method for estimating the refractive index of the medium. Experimental results on both synthetic and real-world data are presented, which demonstrate the effectiveness of the proposed method.     

Experimental determination of the higher electric field level inside an overmoded reverberation chamber using the generalized extreme value distribution

Reverberation chamber (RC), in which a complex electromagnetic environment is created, is of great interest as a versatile test and measurement tool, and its performance is conveniently evaluated through the field statistics. Following a previous paper in which the generalized extreme value (GEV) distribution was proposed to model the maximum field inside an RC, this work presents an experimental validation of the GEV use for the overmoded RC. The electric field is measured with a small sensor for a large number of points inside the RC, and the GEV parameters are accurately estimated. Since the maximum field distribution for this overmoded RC is found to be of reverse Weibull type, the field distribution is right bounded by a higher level that can be determined.     

Cylindrical-rectangular microstrip patch antenna for circularpolarization

The circular polarization condition for a rectangular microstrip patch antenna on a thin cylindrical substrate is investigated. The theoretical study is based on the modal-expansion theory, which is valid for the thin-substrate case. Numerical results for the aspect ratio of the cylindrical-rectangular patch, the optimal feed point for minimum voltage standing wave ratio and the 3-dB bandwidth for circularly polarized radiation are analyzed. Effects of the curvature on the circular polarization condition are also discussed     

Enhanced storage/operation stability of small molecule organic photovoltaics using graphene oxide interfacial layer

Graphene and graphene oxide (GO) have been applied in flexible organic electronic devices with enhanced efficiency of polymeric photovoltaic (OPV) devices. In this work, we demonstrate that storage/operation stability of OPV can be substantially enhanced by spin-coating a GO buffer layer on ITO without any further treatment. With a 2 nm GO buffer layer, the power conversion efficiency (PCE) of a standard copper phthalocyanine (CuPc)/fullerene (C₆₀) based OPV device shows about 30% enhancement from 1.5% to 1.9%. More importantly, while the PCE of the standard device drop to 1/1000 of its original value after 60-days of operation-storage cycles; those of GO-buffered device maintained 84% of initial PCE even after 132-days. Atomic force microscopy studies show that CuPc forms larger crystallites on the GO-buffered ITO substrate leading to better optical absorption and thus photon utilization. Stability enhancement is attributed to the diffusion barrier of the GO layer which slow down diffusion of oxygen species from ITO to the active layers.     

Asymptotic Analysis of Spatially Correlated MIMO Multiple-Access Channels With Arbitrary Signaling Inputs for Joint and Separate Decoding

While the capacity of a single-user, point-to-point, multiple-input multiple-output (MIMO) channel has been well known, the achievable capacity of a MIMO channel in the presence of other co-channel users is much less understood. One such important scenario is the multiple-access (MA) channel where communication occurs from many uncoordinated mobile users to a common base station receiver (i.e., multipoint-to-point). Unlike previous studies whose emphases were on the idealized spatially uncorrelated channels with Gaussian signaling inputs from users, this paper derives a general analytical expression for the asymptotic (in the sense of large-system limit) sum-rate of a MIMO-MA system where the transmitters and the receiver can have different spatial correlations, and the users' inputs are not necessarily Gaussian. In addition to the sum-rate formula that assumes optimal joint decoding at the base station, we also derive the asymptotic sum-rate of a more practical system which performs separate decoding (multiuser detection followed by a bank of temporal error-correction decoders). Our analytic formulae are important in that they reveal the sum-rate one's system can achieve given the spatial correlation structures at the transmitters and receiver, and the input signal distributions. For special cases that users are homogeneous or users have Gaussian inputs, our results degenerate to previously published results. Furthermore, through computer simulations, we see that the proposed asymptotic solution gives good estimates for the ergodic sum-rate of the systems even with only a few antenna elements at each transmitter and receiver     

A 1-V 86-mW-RX 53-mW-TX Single-Chip CMOS Transceiver for WLAN IEEE 802.11a

A 1-V WLAN IEEE 802.11a CMOS transceiver integrates all building blocks on a single chip including a transformer-feedback VCO and a stacked divider for the frequency synthesizer and 8-bit IQ ADCs and 8-bit IQ DACs. Fabricated in a 0.18-mum CMOS process and operated at a single 1-V supply, the receiver and the transmitter consume 85.7 mW and 53.2 mW, including the frequency synthesizer, respectively. The total chip area with pads is 12.5 mm².     

Broad-band dual-polarized single microstrip patch antenna with highisolation and low cross polarization

This paper presents a new design of a broad-band dual-polarized single microstrip patch antenna with highly decoupled input ports and low cross-polarization (XP) radiation. A prototype of the proposed antenna with center frequency at 1800 MHz is presented. Both the dual linear polarizations have 10-dB return-loss impedance bandwidths greater than 14% and high decoupling between the two input ports (S₂₁ less than -40 dB across the entire bandwidths) is obtained. Moreover, the XP radiation in the principal planes of the dual linear polarizations is seen to be less than -20 dB