Directed Explicit Model Checking with HSF-SPIN

We present the explicit state model checker HSF-SPIN which is based on the model checker SPIN and its Promela modeling language. HSF-SPIN incorporates directed search algorithms for checking safety and a large class of LTL-specified liveness properties. We start off from the A* algorithm and define heuristics to accelerate the search into the direction of a specified failure situation. Next we propose an improved nested depth-first search algorithm that exploits the structure of Promela Never-Claims. As a result of both improvements, counterexamples will be shorter and the explored part of the state space will be smaller than with classical approaches, allowing to analyze larger state spaces. We evaluate the impact of the new heuristics and algorithms on a set of protocol models, some of which are real-world industrial protocols

Phytochemical composition and in vitro antioxidant activity of methanolic and aqueous extracts of aerial part of Pentatropis nivalis(Asclepiadaceae)

The objective of present study was to evaluate preliminary phytoconstitutents and invitro antioxidant potential of Pentatropis nivalis (Asclepiadaceae). During the preliminary phytochemical analysis, methanolic and aqueous extracts of aerial part of Pentatropis nivalis was screened for the presence of phenolic, saponins, flavonoids, alkaloids, tannins and phytosterols. TLC of extracts were performed by using various solvent systems. Phytochemicals screening and TLC spots of MEPN and AEPN showed the presence of glycoside, steroids, terpenoids, phenolic, saponins, Methanolic extract showed better qualitative tests for presence of secondary metabolites than aqueous extract.The in-vitro antioxidant potential of extracts were evaluated by DPPH and FRAP, and both methods showed that the plant possesses good antioxidant activity

Natural Language Processing Semantical and Syntactical Analysis for English

Natural language is to facilitate the user to exchange the ideas among people. These ideas converge to form the "meaning" of an utterance or text in the form of a series of sentences. The meaning of sentences describes as semantics. The input/output of a NLP can be a written text or a speech. There are two major components of natural language processing, namely: natural language understanding which describes mapping of given input in the natural language into a useful representation and the other is natural language generation which produce natural language as output on basis of input data as text. This paper deals with natural language understanding mainly on semantic

Experimental and Numerical Study on Vibration-Based Damage Detection and Localization in Laminated Composite Plates

Damage detection in composite materials is crucial for ensuring the safety and reliability of engineering structures. Conventional methods often face challenges in accurately identifying damage in plate-like structures, particularly in scenarios involving multiple damages or small-scale delamination. This study focuses on investigating the detection and localization of delamination in composite plates by employing both experimental and numerical modal analysis. An eight-ply woven Glass-Epoxy composite laminate with and without damage was prepared with the aid of hand lamination technique. Laminate was fixed to a Clamped-Free-Free-Free (CFFF) boundary condition for experimental modal analysis by introducing controlled damage to examine its impact on modal properties. To validate the natural frequencies (NFs) of damaged and undamaged composite laminates, a numerical analysis was conducted using ANSYS Parametric Design Language (APDL). Further, to advance the understanding of using modal shapes and their spatial derivatives for damage localization in composite plates under various damage situations, post-processing of simulation results was conducted using MATLAB. Finite Difference Method has been employed to calculate the derivatives, and a novel damage index (DI) is proposed to enhance damage localization capabilities. The results affirm that the proposed DI is effective and precise in identifying damage in plate-like structures, both for individual and multiple damage scenarios. This research study presents a novel approach for identifying and pinpointing damage in composite plates, thereby making a valuable contribution to the field of structural health monitoring (SHM) application

Pre-Interventional Cardiac and ECG Changes in Acute Organophosphate Poisoning Cases Admitted to a Tertiary Hospital in India

Background: Cardiac complications are the less common fatal effect of acute organophosphate poisoning. This study was undertaken to analyze the pre-interventional cardiac and Electrocardiographic (ECG) changes in acute organophosphate poisoning cases.Materials and Methods: Clinical records of acute organophosphate poisoning patients of age less than 50 years admitted to KLE’s Dr. Prabhakar Kore Hospital, Belgaum, Karnataka, from 01-01-2010 to 31-12-2010 were analyzed. Cases of organophosphate poisonings referred from other hospitals, poisoning with multiple agents, patients with history of previous cardiac diseases and coexisting medical conditions were excluded from the study. Poisoning Severity Score was calculated as per International Programme on Chemical Safety and patients were grouped into 3 grades.Results: In this study, 50 cases of acute organophosphate poisoning (male - 32; female - 18) were analyzed. Sinus tachycardia was present in 45 patients (90%), hypertension in 13 (26%) and hypotension in 12 (24%). Prolonged corrected QT interval was observed in 14 patients (28%), elevated ST segment in 2 (4%), inverted T wave in 13 (26%) and conduction defects in 1 (2%). Among 14 patients with prolonged corrected QT interval, 12 were in grade III and 2 in grade II severity; and, among 13 patients who had inverted T wave, 2 were in grade I, 4 in grade II and 7 in grade III severity. Acidosis, as assessed by blood pH and HCO3, was observed in 22 patients (44%).Conclusion: Fatal cardiac complications do occur in acute organophosphate poisoning, which are overlooked at times as the most common complications expected are respiratory complications. Higher incidence of ECG changes in Grade III cases suggests that if the cardiac complications develop, the patient should be immediately transferred to an intensive cardiac care unit

Shapes and Positions of Black Hole Shadows in Accretion Disks and Spin Parameters of Black Holes

Can we determine a spin parameter of a black hole by observation of a black hole shadow in an accretion disk? In order to answer this question, we make a qualitative analysis and a quantitative analysis of a shape and a position of a black hole shadow casted by a rotating black hole on an optically thick accretion disk and its dependence on an angular momentum of a black hole. We have found black hole shadows with a quite similar size and a shape for largely different black hole spin parameters and a same black hole mass. Thus, it is practically difficult to determine a spin parameter of a black hole from a size and a shape of a black hole shadow in an accretion disk. We newly introduce a bisector axis of a black hole shadow named a shadow axis. For a rotating black hole a shape and a position of a black hole shadow are not symmetric with respect to a rotation axis of a black hole shadow. So, in this case the minimum interval between a mass center of a black hole and a shadow axis is finite. An extent of this minimum interval is roughly proportional to a spin parameter of a black hole for a fixed inclination angle between a rotation axis of a black hole and a direction of an observer. In order to measure a spin parameter of a black hole, if a shadow axis is determined observationally, it is crucially important to determine a position of a mass center of a black hole in a region of a black hole shadow.Comment: 13 pages, 6 figures, accepted for publication in Ap

Inverting the Sachs-Wolfe Formula: an Inverse Problem Arising in Early-Universe Cosmology

The (ordinary) Sachs-Wolfe effect relates primordial matter perturbations to the temperature variations $\delta T/T$ in the cosmic microwave background radiation; $\delta T/T$ can be observed in all directions around us. A standard but idealised model of this effect leads to an infinite set of moment-like equations: the integral of $P(k) j_\ell^2(ky)$ with respect to k ($0<k<\infty$) is equal to a given constant, $C_\ell$, for $\ell=0,1,2,...$. Here, P is the power spectrum of the primordial density variations, $j_\ell$ is a spherical Bessel function and y is a positive constant. It is shown how to solve these equations exactly for ~$P(k)$. The same solution can be recovered, in principle, if the first ~m equations are discarded. Comparisons with classical moment problems (where $j_\ell^2(ky)$ is replaced by $k^\ell$) are made.Comment: In Press Inverse Problems 1999, 15 pages, 0 figures, Late

Drawdown prepreg coating method using epoxy terminated butadiene nitrile rubber to improve fracture toughness of glass epoxy composites

Laminates of fibre-reinforced prepreg have excellent in-plane mechanical properties, but have inadequate performance in the through thickness direction. Here, we address this issue by application of epoxy-terminated butadiene nitrile (ETBN) liquid rubber between the prepreg laminae using an automatic draw bar coating technique. Test results reveal that by adding ETBN in small quantities in the range of 9.33–61.33 g/m2, the interlaminar critical energy release rates (GIc and GIIc) are improved by up to 122% in mode-I and 49% in mode-II. Moreover, this finding is further supported by the dynamic mechanical analysis thermograms that clearly indicate that coating has not altered the Tg of ETBN-coated samples. Scanning electron microscopic analysis of fracture surfaces showed that rubber particles formed micro cavitations in the epoxy, causing localised rubber rich regions. These resin-rich regions require more energy to fracture, resulting in increased toughness of the glass epoxy prepreg systems. </jats:p

Effects of residual stresses on interlaminar radial strength of Glass-Epoxy L-bend composite laminates

The built-in heterogeneity of the composite laminates has been exploited to tailor the stiffness and strength requirements of modern structures to meet the specific functional demands. However, the non-homogeneity in these composites is the root cause for most of their failures. One of the undesirable consequences of the inherited heterogeneity is the development of cure-induced stresses during composite manufacturing. This work aims to investigate the influence of process-induced stresses on interlaminar radial strength in curved composite laminates. Glass-Epoxy (GE) laminates of two different thicknesses were prepared by hand lamination technique using V-shaped tooling and cured under room temperature. The state of residual stresses in GE laminates is varied by post-curing these laminates at different temperatures. Curved bending strength (CBS) and corresponding interlaminar radial stress for delamination of L-bend laminates were evaluated experimentally using four points bending test. The residual stress profile in each GE laminate is experimentally characterized by employing the Slitting method. The results indicate that the residual stresses have a negligible effect on the critical stress for initial delamination in GE laminates. But, the critical stress for delamination was found to be independent of the laminate thickness and increased with higher curing temperatures. The delaminated surfaces of L-bend laminates were studied using a scanning electronic microscope (SEM). The enhancement in the critical stress due to post-curing can be attributed to the improved fiber-matrix interfacial bonding with higher curing temperature