Formation of porous silicon at elevated temperatures

The features of electrochemical formation process of porous silicon (PS) at the temperatures above the room temperature have been studied. It was found that besides electrochemical dissolution, chemical etching takes part in the formation process of PS even for concentrated HF electrolyte. The role of chemical etching increases with temperature causing an increase of the porosity and the crater depth. The temperature dependence of chemical etching rate has been established. Obtained results enable to conclude that OH⁻ ions play a major role in the chemical etching. Electrochemical etching allows to fabricate PS with good surface quality at the temperatures at least below 65 °C provided that HF electrolyte is concentrated.     

Generating shapes by analogies: An application to hearing aid design

3D shape modeling is a crucial component of rapid prototyping systems that customize shapes of implants and prosthetic devices to a patient’s anatomy. In this paper, we present a solution to the problem of customized 3D shape modeling using a statistical shape analysis framework. We design a novel method to learn the relationship between two classes of shapes, which are related by certain operations or transformation. The two associated shape classes are represented in a lower dimensional manifold, and the reduced set of parameters obtained in this subspace is utilized in an estimation, which is exemplified by a multivariate regression in this paper. We demonstrate our method with a felicitous application to the estimation of customized hearing aid devices.     

Modeling the behavior of longwall coal mine gate roadways subjected to dynamic loading

In order to characterize the behavior of a main gate during retreating of longwall faces and to evaluate the performances of five different support types, including rock bolts and steel sets, a total of 21 convergence and 18 floor-heave stations were installed. Consequently, about 11,500 convergence and 7200 floor-heave data points were obtained over a period of 14 months. In order to simulate the behavior of a supported main gate roadway, a convergence model, represented by an exponential function, was developed on the basis of statistical analyses. In addition to the convergence model, convergence–velocity and convergence–acceleration models were also derived and interpreted in terms of gate road behavior. It was determined that the convergence depends on the loading region, the time, the location of the upper and lower longwall faces, the support type and pattern, and the static and dynamic support loads. Convergence–velocity and acceleration curves provide better means to interpret the performance of supports and gate roadway behavior.     

Retrieval of information about turbulence in rain by using Doppler-polarimetric Radar

This paper considers new possibilities of turbulence intensity retrieval by using Doppler and Doppler-polarimetric radar sounding. Peculiarities of microwave scattering on moving droplets of different size and shape underlie new methods that are introduced, discussed, and checked by using radar data     

Restoration of error-diffused images using projection onto convexsets

A novel inverse halftoning method is proposed to restore a continuous tone image from a given half-tone image. A set theoretic formulation is used where three sets are defined using the prior information about the problem. A new space-domain projection is introduced assuming the halftoning is performed using error diffusion, and the error diffusion filter kernel is known. The space-domain, frequency-domain, and space-scale domain projections are used alternately to obtain a feasible solution for the inverse halftoning problem which does not have a unique solution.     

Pearling: Stroke segmentation with crusted pearl strings

We introduce a novel segmentation technique, called Pearling, for the semi-automatic extraction of idealized models of networks of strokes (variable width curves) in images. These networks may for example represent roads in an aerial photograph, vessels in a medical scan, or strokes in a drawing. The operator seeds the process by selecting representative areas of good (stroke interior) and bad colors. Then, the operator may either provide a rough trace through a particular path in the stroke graph or simply pick a starting point (seed) on a stroke and a direction of growth. Pearling computes in realtime the centerlines of the strokes, the bifurcations, and the thickness function along each stroke, hence producing a purified medial axis transform of a desired portion of the stroke graph. No prior segmentation or thresholding is required. Simple gestures may be used to trim or extend the selection or to add branches. The realtime performance and reliability of Pearling results from a novel disk-sampling approach, which traces the strokes by optimizing the positions and radii of a discrete series of disks (pearls) along the stroke. A continuous model is defined through subdivision. By design, the idealized pearl string model is slightly wider than necessary to ensure that it contains the stroke boundary. A narrower core model that fits inside the stroke is computed simultaneously. The difference between the pearl string and its core contains the boundary of the stroke and may be used to capture, compress, visualize, or analyze the raw image data along the stroke boundary.     

Creating data resources for designing usercentric frontends for query-by-humming systems

Advances in music retrieval research greatly depend on appropriate database resources and their meaningful organization. In this paper we describe data collection efforts related to the design of query-by-humming (QBH) systems. We also provide a statistical analysis for categorizing the collected data, especially focusing on intersubject variability issues. In total, 100 people participated in our experiment, resulting in around 2000 humming samples drawn from a predefined melody list consisting of 22 different well-known music pieces and over 500 samples of melodies that were chosen spontaneously by our subjects. These data are being made available to the research community. The data from each subject were compared to the expected melody features, and an objective measure was derived to quantify the statistical deviation from the baseline. The results showed that the uncertainty in human humming varies depending on the musical structure of the melodies and the musical background of the subjects. Such details are important for designing robust QBH systems. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and full citation on the first page. To copy otherwise, or republish, to post on servers, or to redistribute to lists requires prior specific permission and/or a fee.     

Effects of 1WT.% Ti,In, and Sn Additions on the Microstructure,Mechanical and Corrosion Properties of the As-Cast and Hot-Rolled AM60 Magnesium Alloys

Metal Science and Heat Treatment - We study the influence of 1 wt.% Ti, In and Sn additions on the microstructure, mechanical properties and corrosion resistance of the as-cast and hot-rolled AM60...     

Synthesis and Characterization of Multiwall-Carbon Nanotubes Decorated with Nickel Ferrite Hybrid

Acid functionalized multiwall carbon nanotube, (MWCNT)-COOH/nickel ferrite (NiFe₂O₄), magnetic hybrids were synthesized by a co-precipitation method. X-ray diffraction, Fourier transform infrared spectrometry, thermal gravimetry, transmission electron microscopy, vibrating sample magnetometry and Impedance Spectroscopy were used to characterize the physical and electrical properties of the MWCNT-COOH/NiFe₂O₄ hybrid. NiFe₂O₄ NPs are stably attached to the surface of via carboxyl groups (COOH). The magnetic saturation value of the product was found as 8 emu/g. A tunneling conduction mechanism was believed to occur in the hybrid. The real modules (M′) of the product illustrate power law variation with a power exponent of approximately unity. These magnetic MWCNT-COOH/NiFe₂O₄ hybrids exhibit a promising prospective in the application of bio-nanoscience and technology.     

Daily peak ozone forecast in Istanbul

In this study, we attempt to develop an ozone forecast model using two different approaches. The first approach is to use a multiple linear regression method and the second is to use a feed-forward artificial neural network. Models are developed for the ozone period of April through to September of the years 2002 and 2003 and verified for May to August 2004. In both models, 19 predictors are used. Calculated agreement indices (AI) for the model development period are 0.82 for the linear regression model and 0.88 for the artificial neural network model. On the other hand, AI values decrease to 0.53 and 0.64 for the validation period. Poor performance of the models in the validation phase might be due to the different maximum daily ozone averages of these two periods. While the average of maximum ozone values is 61.1 μg m^?3 in the model development phase, it is 42.2 μg m^?3 in the model validation phase.