Twinning and the mechanical behavior of magnesium alloys at very high strain rates

The dynamic mechanical behavior of magnesium and its alloys is a subject of interest primarily because of its high specific strength. This makes it attractive for structural components and vehicles. The hexagonal close packed crystal structure of magnesium makes it highly anisotropic in terms of its mechanical behavior. Extension twinning is a dominant deformation mechanism in these materials. This is often reflected in a characteristic sigmoidal profile of the stress–strain curve when crystals are compressed along directions perpendicular to the crystallographic c-axis. Past experiments have been limited to strain rates of 103 s–1 . This study focuses on microstructural twinning effects on the mechanical behavior of AZ31 magnesium alloy at higher strain rates. We perform very high-strain rate experiments on AZ31 magnesium alloy, using a miniature Kolsky compression bar apparatus coupled with a high speed camera for whole field imaging. This experiment is capable of achieving strain rates on the order of 105 s–1 . Experiments at these strain rates have shown substantial plastic deformation without failure when compared with the lower rates of loading. This is evidence of deformation mechanisms that tend to delay failure in the material. We also observe a change in the hardening rates between these experiments and experiments done at 103 s–1. Examination of the microstructure of deformed samples gives us information about the relative activation and growth of deformation mechanisms that cause plastic deformation at these rates

A Real Time Image Fusion based Framework for Concealed Weapon Detection

In this paper, a well-organized hidden weapon detection (CWD) algorithm based on image fusion is presented. First, the images obtained consumingdissimilar sensors are decomposed into low and high occurrence bands with the double-density dualtree compound wavelet transform (DDDTCWT). Then two novel decision methods are introduced referring to the appearances of the frequency bands, which meaningfully improves the image fusion performance. The fusion of low frequency bands coefficients is strong-minded by the local contrast, while the high occurrence band fusion rule is developed by considering both the texture feature of HVS and the local energy basis. Finally, the fused image is attained through the inverse DDDTCWT. Experiments and comparisons establish the robustness and efficiency of the proposed approach and indicate that the fusion rules can be applied to different multi-scale transforms. Also, our work shows that the mixture result using the proposed fusion rules on DDDTCWT is superior to other mixtures as well as previously proposed approaches

SEASONAL CROP YIELD FORECASTING-METHODS, ACCURACIES AND LIMITATIONS: A REVIEW

Accurate crop yield forecasting helps the government to formulate sound policies related to import and exports, allocation of food grains and price setting. Similarly, the traders and industries can make decisions regarding business activities like wages, purchase of raw materials and working hours. Crop management practices can be standardized to get maximum yield to reduce the pre and post harvest losses of produce. The impact of climate change on the crops can also be known. This forecasting can be done using different techniques like statistical models and crop simulation models. The information of weather, plant characters, environment, remote sensors etc. can be used as input data for forecasting. It can be concluded that forecasting the crop yield near the harvest is more accurate, with r2= 0.7-0.8 being predominant than at the early stages (r2=0.5-0.6). Further improvement in the accuracy in forecasting is possible with the use of artificial intelligence and machine learning

Synchrophasor Technology for Cyber Security in Smart Grid

Smart grid is controlled by an authority personnel who uses LAN or the internet to control it. By knowing this information any one from outside can control the smart grid using LAN or the internet. This process of hacking the smart grid control is known as aurora attack. The Aurora attack may pose a risk to rotating machinery operating under certain conditions on the electrical grid. The Aurora attack involves opening and closing one or more circuit breakers, resulting in an out-of-synchronism condition that may damage rotating equipment connected to the power grid.This paper focuses on the Aurora attack on a synchronous generator and the existing technology available to mitigate the attack. The root cause of the vulnerability is breakdown in security. The first level prevents the attack with sound security practices. The second level protects the equipment in the event that the security level is compromised. The equipment can be protected using wide-area synchronized phasor measurement and protection system and security considerations

The Effect of Pre-Injury Anti-Platelet Therapy on the Development of Complications in Isolated Blunt Chest Wall Trauma: A Retrospective Study

INTRODUCTION: The difficulties in the management of the blunt chest wall trauma patient in the Emergency Department due to the development of late complications are well recognised in the literature. Pre-injury anti-platelet therapy has been previously investigated as a risk factor for poor outcomes following traumatic head injury, but not in the blunt chest wall trauma patient cohort. The aim of this study was to investigate pre-injury anti-platelet therapy as a risk factor for the development of complications in the recovery phase following blunt chest wall trauma. METHODS: A retrospective study was completed in which the medical notes were analysed of all blunt chest wall trauma patients presenting to a large trauma centre in Wales in 2012 and 2013. Using univariate and multivariable logistic regression analysis, pre-injury platelet therapy was investigated as a risk factor for the development of complications following blunt chest wall trauma. Previously identified risk factors were included in the analysis to address the influence of confounding. RESULTS: A total of 1303 isolated blunt chest wall trauma patients presented to the ED in Morriston Hospital in 2012 and 2013 with complications recorded in 144 patients (11%). On multi-variable analysis, pre-injury anti-platelet therapy was found to be a significant risk factor for the development of complications following isolated blunt chest wall trauma (odds ratio: 16.9; 95% confidence intervals: 8.2-35.2). As in previous studies patient age, number of rib fractures, chronic lung disease and pre-injury anti-coagulant use were also found to be significant risk factors. CONCLUSIONS: Pre-injury anti-platelet therapy is being increasingly used as a first line treatment for a number of conditions and there is a concurrent increase in trauma in the elderly population. Pre-injury anti-platelet therapy should be considered as a risk factor for the development of complications by clinicians managing blunt chest wall trauma

Corrigendum: Systemic contact dermatitis related to alcoholic beverage consumption

The original article was published on September 15, 2019 and corrected on November 15, 2019.The revised version of the article adds a missing author. This change appears in the revised online PDF copy of this article

HERMITIAN SYMMETRY BASED FIBER NON-LINEARITY COMPENSATION IN OPTICAL OFDM NETWORKS

Orthogonal Frequency Division Multiplexing (OFDM) is a modulation technique which is now used in most new and emerging broadband wired and wireless communication systems such as standard 802.11a/b/g/n, Digital Video Broad casting Television (DVB-TV), and Long Term Evolution (LTE) in the next mobile generation, due to its capacity in solving the problems of Inter-Symbol Interference (ISI) caused by the effects of the dispersive channel. Very recently researches focus on applying OFDM technology in optical fiber communication systems. Optical OFDM is well suited for high speed transmission systems with high spectral efficiency and attracted significant attention from the optical communication community. One of the major issues that degrade the performance of optical OFDM networks is its fiber non-linearity. Fiber non-linearities represent the fundamental limiting mechanisms to the amount of data that can be transmitted on a single optical fiber. Non-linear effects arise as optical fiber data rates, transmission lengths, number of wavelengths, and optical power level increases. Therefore, the effect of non-linearity in high data rate optical networks needs to be controlled to enhance link performances. In this paper, a nonlinearity compensation technique (Hermitian Symmetry) is implemented to improve the performance of OFDM based optical networks. This would provide high spectral efficiency, low ISI and very good Bit Error Rate (BER) performances without increasing the complexity of the network. The optical OFDM transmission system with fiber non-linearity compensation is simulated using Virtual Photonics Integrated (VPI) software

Investigation on Tensile and Flexural Strength of KOH Treated Ridge Gourd Fiber-Polyester Resin Composite

Abstract- Natural fiber is abundantly availing in nature. Nowadays this is used in composite materials. In general ridge gourd fiber is very strength material due to its woven. So this fiber is using in composites. Here potassium hydroxide (KOH) treated ridge gourd fiber is used in composite. One of the traditional methods, hand lay – up method is to use for preparing ridge gourd fiber reinforcing polyester composite. Specimens are to be test as per ASTM standards. Tensile and flexural strength are analyzed and optimize the parameters. Then, the fractured surfaces are analyzed with the help of SEM images. DOI: 10.17762/ijritcc2321-8169.150312

Video Quality Assessment with Texture Information Fusion for Streaming Applications

The rise in video streaming applications has increased the demand for video quality assessment (VQA). In 2016, Netflix introduced Video Multi-Method Assessment Fusion (VMAF), a full reference VQA metric that strongly correlates with perceptual quality, but its computation is time-intensive. We propose a Discrete Cosine Transform (DCT)-energy-based VQA with texture information fusion (VQ-TIF) model for video streaming applications that determines the visual quality of the reconstructed video compared to the original video. VQ-TIF extracts Structural Similarity (SSIM) and spatiotemporal features of the frames from the original and reconstructed videos and fuses them using a long short-term memory (LSTM)-based model to estimate the visual quality. Experimental results show that VQ-TIF estimates the visual quality with a Pearson Correlation Coefficient (PCC) of 0.96 and a Mean Absolute Error (MAE) of 2.71, on average, compared to the ground truth VMAF scores. Additionally, VQ-TIF estimates the visual quality at a rate of 9.14 times faster than the state-of-the-art VMAF implementation, along with an 89.44 % reduction in energy consumption, assuming an Ultra HD (2160p) display resolution.Comment: 2024 Mile High Video (MHV