Effect of nonlocal elasticity on the performance of a flexoelectric layer as a distributed actuator of nanobeams

The paper is concerned with the development of finite element model for the static analysis of smart nanobeams integrated with a flexoelectric layer on its top surface, using nonlocal elastic theory. The flexoelectric layer acts as a distributed actuator of the nanobeam. A layerwise displacement theory has been used to derive the element stiffness matrices from variational principles incorporating nonlocal effects. The finite element model for nonlocal response of the beams has been validated with the exact solution for the case of a simply supported standalone flexoelectric layer. Also, the finite element model of the simply supported smart beam has been validated with exact solutions and numerical models for the local elastic case. The performance of the flexoelectric actuator has been compared for different values of nonlocal parameters and different combinations of nonlocal and local elastic substrate and flexoelectric layer. Further, the model developed has been utlized for investigating the performance of the active flexoelectric layer in case of cantilever beam, for which the exact solutions are not available.     

Assessing vulnerability exploitability risk using software properties

Attacks on computer systems are now attracting increased attention. While the current trends in software vulnerability discovery indicate that the number of newly discovered vulnerabilities continues to be significant, the time between the public disclosure of vulnerabilities and the release of an automated exploit is shrinking. Thus, assessing the vulnerability exploitability risk is critical because this allows decision-makers to prioritize among vulnerabilities, allocate resources to patch and protect systems from these vulnerabilities, and choose between alternatives. Common vulnerability scoring system (CVSS) metrics have become the de facto standard for assessing the severity of vulnerabilities. However, the CVSS exploitability measures assign subjective values based on the views of experts. Two of the factors in CVSS, Access Vector and Authentication, are the same for almost all vulnerabilities. CVSS does not specify how the third factor, Access Complexity, is measured, and hence it is unknown whether it considers software properties as a factor. In this work, we introduce a novel measure, Structural Severity, which is based on software properties, namely attack entry points, vulnerability location, the presence of the dangerous system calls, and reachability analysis. These properties represent metrics that can be objectively derived from attack surface analysis, vulnerability analysis, and exploitation analysis. To illustrate the proposed approach, 25 reported vulnerabilities of Apache HTTP server and 86 reported vulnerabilities of Linux Kernel have been examined at the source code level. The results show that the proposed approach, which uses more detailed information, can objectively measure the risk of vulnerability exploitability and results can be different from the CVSS base scores.     

Assessment of Risk of Musculoskeletal Disorders among Crane Operators in a Steel Plant: A Data Mining–Based Analysis

Prevalence of musculoskeletal disorders (MSD) among industrial workers is often measured through the Nordic Musculoskeletal Questionnaire (NMQ) survey that captures the MSD complaints across different body parts. The outcomes of such a survey are reported in terms of relative frequency of MSD complaints for the body parts affected and are analyzed through t test, analysis of variance, or logistic regression. The study augments the analysis of NMQ data using relative risk, a statistical measure of prevalence, and classification and regression tree (CART), a data mining–based decision tree. The integrated analysis is done for 76 crane operators of a steel plant in India that considers operators, task, and workplace characteristics as predictors of MSD. The relative risk indices for each of the predictor categories compare the risk of prevalence of MSD. The outcomes of CART‐based analysis are objective importance scores that quantify the contributions of the predictors toward the occurrence and severity of MSD. A risk priority index is computed to prioritize the predictor variables with categories in terms of their contribution. The study shows that the lower back and neck and shoulder are the most affected and account for 78.75% of the MSD complaints. CART shows that crane height contributes the maximum for MSD occurrences of both lower back and neck and shoulder. However, for MSD severity, while crane height contributes the most for neck and shoulder, cabin feature (static or movable) contributes the maximum for the lower back.     

A Novel Cascaded PID Controller for Automatic Generation Control Analysis With Renewable Sources

Present day power scenarios demand a high quality uninterrupted power supply and needs environmental issues to be addressed. Both concerns can be dealt with by the introduction of the renewable sources to the existing power system. Thus, automatic generation control (AGC) with diverse renewable sources and a modified-cascaded controller are presented in the paper. Also, a new hybrid scheme of the improved teaching learning based optimization-differential evolution (hITLBO-DE) algorithm is applied for providing optimization of controller parameters. A study of the system with a technique such as TLBO applied to a proportional integral derivative (PID), integral double derivative (IDD) and PIDD is compared to hITLBO-DE tuned cascaded controller with dynamic load change.The suggested methodology has been extensively applied to a 2-area system with a diverse source power system with various operation time non-linearities such as dead-band of, generation rate constraint and reheat thermal units. The multi-area system with reheat thermal plants, hydel plants and a unit of a wind-diesel combination is tested with the cascaded controller scheme with a different controller setting for each area. The variation of the load is taken within 1% to 5% of the connected load and robustness analysis is shown by modifying essential factors simultaneously by ± 30%. Finally, the proposed scheme of controller and optimization technique is also tested with a 5-equal area thermal system with non-linearities. The simulation results demonstrate the superiority of the proposed controller and algorithm under a dynamically changing load.      

Influence of Time Discretization and Input Parameter on the ANN Based Synthetic Streamflow Generation

The capability of ANN to generate synthetic series of river discharge averaged over different time steps with limited data has been investigated in the present study. While an ANN model with certain input parameters can generate a monthly averaged streamflow series efficiently; it fails to generate a series of smaller time steps with the same accuracy. The scope of improving efficiency of ANN in generating synthetic streamflow by using different combinations of input data has been analyzed. The developed models have been assessed through their application in the river Subansiri in India. Efficiency of the ANN models has been evaluated by comparing ANN generated series with the historical series and the series generated by Thomas-Fiering model on the basis of three statistical parameters-periodical mean, periodical standard deviation and skewness of the series. The results reveal that the periodical mean of the series generated by both Thomas–Fiering and ANN models are in good agreement with that of the historical series. However, periodical standard deviation and skewness coefficient of the series generated by Thomas–Fiering model is inferior to that of the series generated by ANN.     

Oxidation of caffeine by acid‐activated ferrate(VI): Effect of ions and natural organic matter

Caffeine (CAF) is the most commonly consumed stimulant and frequently detected emerging pollutant in influents and effluents of wastewater treatment plants (WWTP) and surface waters. Acid‐activated ferrate(VI) (Fe^VI , Fe(VI)) oxidizes CAF in water in seconds to minutes at three times lower molar ratio of Fe(VI) to CAF than oxidative transformation observed in hours by nonactivated Fe(VI) (8.0 vs. 25.0). CAF oxidation by acid‐activated Fe(VI) is not affected by ionic constituents of water. Organic components of natural organic matter (NOM) and secondary effluent wastewater (SE) decrease efficiency of CAF transformation. However, acid‐activated Fe(VI) could mineralize other organics present in both NOM and SE as indicated by the dissolved organic carbon (DOC) removal. Comparatively, no mineralization was seen without activation of Fe(VI). Four oxidized products of CAF were identified by a liquid chromatography high resolution mass spectrometry technique. The reaction pathways of the oxidation of CAF by activated Fe(VI) have been proposed. © 2017 American Institute of Chemical Engineers AIChE J, 2017     

Production of Flexible Transparent Conducting Films of Self‐Fused Nanowires via One‐Step Supersonic Spraying

Scalable and economical manufacturing of flexible transparent conducting films (TCF) is a key barrier to widespread adoption of low‐cost flexible electronics. Here, a simple, robust, and scalable method of flexible TCF formation using supersonic kinetic spraying is demonstrated. Silver nanowire (AgNW) suspensions are sprayed at supersonic speed to produce self‐sintered films of AgNWs on flexible substrates. These films display remarkably low sheet resistance, <10 Ω sq^?1, combined with high transmittance, >90%. These electrically conducting, transparent, and flexible coatings can be deposited over a 100 cm² area in ≈30 s. Theoretical analysis reveals the underlying physical mechanism behind self‐sintering, showing that self‐sintering is enabled by the high velocity of impact in supersonic spraying.     

Cauchy with whale optimizer based eagle strategy for multi-level color hematology image segmentation

Neural Computing and Applications - Pathological color image segmentation is an exigent procedure due to the existence of imperceptibly correlated, and indistinct multiple regions of concern....