Generalized problem of thermal bending analysis in the Cartesian domain

This is an attempt for mathematical formulation and general analytical solution of the most generalized thermal bending problem in the Cartesian domain. The problem has been formulated in the context of non-homogeneous transient heat equation subjected to Robin’s boundary conditions. The general solution of the generalized thermoelastic problem has been discussed for temperature change, displacements, thermal stresses, deflection, and deformation. The most important feature of this work is any special case of practical interest may be readily obtained by this most generalized mathematical formulation and its analytical solution. There are 729 such combinations of possible boundary conditions prescribed on parallelepiped shaped region in the Cartesian coordinate system. The key idea behind the solution of heat equation is to transform the original initial and boundary value problem into eigenvalue problem through the Strum-Liouville theory. The finite Fourier transform has been applied with respect to space variables by choosing suitable normalized kernels. The well-posedness of the problem has been discussed by the existence, uniqueness, and stability of series solutions obtained analytically. The convergence of infinite series solutions also been discussed

ANOMALY DETECTION OF EVENTS IN CROWDED ENVIRONMENT AND STUDY OF VARIOUS BACKGROUND SUBTRACTION METHODS

Anomalous behavior detection and localization in videos of the crowded area that is specific from a dominant pattern are obtained. Appearance and motion information are taken into account to robustly identify different kinds of an anomaly considering a wide range of scenes. Our concept based on a histogram of oriented gradients and Markov random field easily captures varying dynamic of the crowded environment.Histogram of oriented gradients along with well-known Markov random field will effectively recognize and characterizes each frame of each scene. Anomaly detection using artificial neural network consist both appearance and motion features which extract within spatio temporal domain of moving pixels that ensures robustness to local noise and thus increases accuracy in detection of a local anomaly with low computational cost.To extract a region of interest we have to subtract background. Background subtraction is done by various methods like Weighted moving mean, Gaussian mixture model, Kernel density estimation.

Random on-board pixel sampling (ROPS) X-ray Camera

Recent advances in compressed sensing theory and algorithms offer new possibilities for high-speed X-ray camera design. In many CMOS cameras, each pixel has an independent on-board circuit that includes an amplifier, noise rejection, signal shaper, an analog-to-digital converter (ADC), and optional in-pixel storage. When X-ray images are sparse, i.e., when one of the following cases is true: (a.) The number of pixels with true X-ray hits is much smaller than the total number of pixels; (b.) The X-ray information is redundant; or (c.) Some prior knowledge about the X-ray images exists, sparse sampling may be allowed. Here we first illustrate the feasibility of random on-board pixel sampling (ROPS) using an existing set of X-ray images, followed by a discussion about signal to noise as a function of pixel size. Next, we describe a possible circuit architecture to achieve random pixel access and in-pixel storage. The combination of a multilayer architecture, sparse on-chip sampling, and computational image techniques, is expected to facilitate the development and applications of high-speed X-ray camera technology.Comment: 9 pages, 6 figures, Presented in 19th iWoRI

The comparison of apache II and apache IV score to predict mortality in intensive care unit in a tertiary care hospital

Background: The prognostication of critically ill patients, in a systematic way, based on definite objective data is an integral part of the quality of care in Intensive Care Unit (ICU). Acute physiology and chronic health evaluation (APACHE) scoring systems provide an objective means of mortality prediction in Intensive Care Unit (ICU). The aims of this study were to compare the performance of APACHE II and APACHE IV in predicting mortality in our intensive care unit (ICU).Methods: A prospective observational study was conducted in a 13 bedded intensive care unit (ICU) of a tertiary level teaching hospital. All the patients above the age of 12 years, irrespective of diagnosis managed in ICU for >24hours were enrolled. APACHE II and APACHE IV scores were calculated based on the worst values in the first 24hours of admission. All enrolled patients were followed up, and outcome was recorded as survivors or non survivors. Observed mortality rates were compared with predicted mortality rates for both the APACHE II and APACHE IV. Receiver operator characteristic curves (ROC) were used to compare accuracy of the two scores.Results: APACHE II score of the patients ranged from 1 to 32 and APACHE IV score of the patients ranged from 25 to 142. There was good correlation between APACHE II and APACHE IV scores with the spearman’s rho value of 0.776 (P<0.01). Discrimination for APACHE II and APACHE IV models were good with area under ROC curve of 0.805 and 0.832 respectively. APACHE IV was more accurate than APACHE II in this regard. The cut-off point with best Youden index for APACHE II was 17 and for APACHE IV were 72 respectively for predicting mortality.Conclusions: Discrimination was better for APACHE IV than APACHE II model however Calibration was better for APACHE II than APACHE IV model in present study. There was good correlation between the two models observed in present study

Electric Field Assisted Self-Healing of Open Circuits with Conductive Particle-Insulating Fluid Dispersions: Optimizing Dispersion Concentration

Abstract: Open circuit faults in electronic systems are a common failure mechanism, particularly in large area electronic systems such as display and image sensor arrays, flexible electronics and wearable electronics. To address this problem several methods to self heal open faults in real time have been investigated. One approach of interest to this work is the electric field assisted self-healing (eFASH) of open faults. eFASH uses a low concentration dispersion of conductive particles in an insulating fluid that is packaged over the interconnect. The electric field appearing in the open fault in a current carrying interconnect polarizes the conductive particles and chains them up to create a heal. This work studies the impact of dispersion concentration on the heal time, heal impedance and cross-talk when eFASH is used for self-healing. Theoretical predictions are supported by experimental evidence and an optimum dispersion concentration for effective self-healing is identified

Intermediate statistics for a system with symplectic symmetry: the Dirac rose graph

We study the spectral statistics of the Dirac operator on a rose-shaped graph---a graph with a single vertex and all bonds connected at both ends to the vertex. We formulate a secular equation that generically determines the eigenvalues of the Dirac rose graph, which is seen to generalise the secular equation for a star graph with Neumann boundary conditions. We derive approximations to the spectral pair correlation function at large and small values of spectral spacings, in the limit as the number of bonds approaches infinity, and compare these predictions with results of numerical calculations. Our results represent the first example of intermediate statistics from the symplectic symmetry class.Comment: 26 pages, references adde

Simultaneous X-ray diffraction and phase-contrast imaging for investigating material deformation mechanisms during high-rate loading

Using a high-speed camera and an intensified charge-coupled device (ICCD), a simultaneous X-ray imaging and diffraction technique has been developed for studying dynamic material behaviors during high-rate tensile loading. A Kolsky tension bar has been used to pull samples at 1000 s(−1) and 5000 s(−1) strain-rates for super-elastic equiatomic NiTi and 1100-O series aluminium, respectively. By altering the ICCD gating time, temporal resolutions of 100 ps and 3.37 µs have been achieved in capturing the diffraction patterns of interest, thus equating to single-pulse and 22-pulse X-ray exposure. Furthermore, the sample through-thickness deformation process has been simultaneously imaged via phase-contrast imaging. It is also shown that adequate signal-to-noise ratios are achieved for the detected white-beam diffraction patterns, thereby allowing sufficient information to perform quantitative data analysis diffraction via in-house software (WBXRD_GUI). Of current interest is the ability to evaluate crystal d-spacing, texture evolution and material phase transitions, all of which will be established from experiments performed at the aforementioned elevated strain-rates

Effect of freshwater influx on phytoplankton in the Mandovi estuary (Goa, India) during monsoon season: Chemotaxonomy

The Mandovi estuary is a prominent water body that runs along the west coast ofIndia. It forms an estuarine network with the adjacent Zuari estuary, connected via the Cumbharjua canal. The physico-chemical conditions seen in the Mandovi estuary are influenced by two factors: the fresh water runoff during the monsoon season (June-September) and the tidal influx of coastal seawater during the summer (October to May) season. However, the effects of monsoon related changes on the phytoplankton of the Mandovi estuary are not yet fully understood. An attempt to understand the same has been made here by applying the process of daily sampling at a fixed station throughout the monsoon season. It was noticed that the onset of the monsoon is responsible for an increase in nitrate levels upto 26 μM from <1 μM during pre-monsoon and enhancement of chlorophyll a (chl a) as high as 14 μg·L-1 during the same period. The phytoplankton population was observed through both chemotaxonomy and microscopy and was found to be composed mainly of diatoms. CHEMTAX analysis further uncovers the presence of several other groups of phytoplankton, the presence of which is yet to be reported in many other tropical estuaries. It includes chrysophytes, cyanobacteria, prasinophytes, prymnesiophytes and chlorophytes. The appearance of phytoplankton groups at various stages of the monsoon was recorded, and this data is discussed in relation to environmental changes in the Mandovi estuary during the monsoon season

Pore Elimination Mechanisms during 3D Printing of Metals

Laser powder bed fusion (LPBF) is a 3D printing technology that can print metal parts with complex geometries without the design constraints of traditional manufacturing routes. However, the parts printed by LPBF normally contain many more pores than those made by conventional methods, which severely deteriorates their properties. Here, by combining in-situ high-speed high-resolution synchrotron x-ray imaging experiments and multi-physics modeling, we unveil the dynamics and mechanisms of pore motion and elimination in the LPBF process. We find that the high thermocapillary force, induced by the high temperature gradient in the laser interaction region, can rapidly eliminate pores from the melt pool during the LPBF process. The thermocapillary force driven pore elimination mechanism revealed here may guide the development of 3D printing approaches to achieve pore-free 3D printing of metals