Standard gradient models and crack simulation

The standard gradient models have been intensively studied in the literature, cf. Fremond (1985) or Gurtin (1991) for various applications in plasticity, damage mechanics and phase change analysis. The governing equations for a solid have been introduced essentially from an extended version of the virtual equation. It is shown here first that these equations can also be derived from the formalism of energy and dissipation potentials and appear as a generalized Biot equation for the solid. In this spirit, the governing equations for higher gradient models can be straightforwardly given. The interest of gradient models is then discussed in the context of damage mechanics and crack simulation. The phenomenon of strain localization in a time-dependent or time-independent process of damage is explored as a convenient numerical method to simulate the propagation of cracks, in relation with some recent works of theliterature, cf. Bourdin Marigo [3], Lorentz al  [5], Henry al [12]

Numerical simulation of the crack 2D by the finite element incorporated the discontinuity

Determining stress intensity factors is important in fracture mechanics. The extended finite element method (XFEM) provides a robust and accurate to determine factors. This paper describes some results from the analysis of cracked plates using XFEM. Extended finite elements allow the entire crack to be represented independently of the meshing. The elements employ discontinuous functions and the facture mechanics two dimensional asymptotic crack tip displacement fields. The Fortran source code of Cast3M applies these elements to a set of examples. The obtained stress and deformation fields are used to compute stress intensity factors via interaction integrals. The results are compared with these obtained from conventional FEM to demonstrate the advantages of the employing the new elements

Study the appropriate conditions to obtain germinated brown rice with high biological activity

ABSTRACT – QMFS 2019Germinated brown rice strains contain more bioactive substances than germinated regular rice ones, however germination conditions play an important role in the activity and the content of those substances. The proper germination process provides the optimized active ingredients from rice that can be used for the production of nutritious beverages. In this study, we investigated the effects of pH, temperature and incubation time in microaerobic culture condition on the change of bioactive substances in AnhDao brown rice. The optimal germination condition with pH at 3, temperature of 35 0C and time for 36h release 109.11U/g of the α-amylase activity, 17.22(U/g) of the enzyme glutamate decacboxylase (GAD), 1.38(U/g) of protease, 231.76mg/100g of GABA content and 21.9 (mgGAE/100g) of polyphenol from germinated AnhDao brown rice. In nutrient evaluation, germinated AnhDao brown rice contains 65.53% of starch, 2.49% of lipid, 9.13%of protein, 2.04% of reducing sugar, and 1.26% of ash.Key words: Germinated brown rice, bioactive substances, α-amylase, protease, glutamate decacboxylase (GAD), Gamma aminobutyric acid (GABA)

Performance and security tradeoffs of provable website traffic fingerprinting defenses over Tor

The Internet has become an integral part of modern life. At the same time, as we spend increasingly more time online, our digital trails, including the identities of the websites we visit, can reveal sensitive personal information. As a result, researchers have devised schemes that seek to enable users to obfuscate the network traffic fingerprints of the websites they visit; however, being ad hoc attempts, these schemes have all been later found to be ineffective against more sophisticated attacks. Thus, researchers have recently proposed a family of provable defenses called BuFLO, or Buffered Fixed-Length Obfuscator, that provides strong privacy guarantees at the expense of high overhead. Orthogonal to these defenses, the popular Tor anonymity network provides some protection against these attacks but is nonetheless susceptible. In this dissertation, we propose a simple design that uses BuFLO to protect web browsing traffic over Tor: tunnel the BuFLO channel through Tor. In order to evaluate the design, for both live experiments as well as large-scale simulations, we need precise models of the traffic profiles generated by a browser's visiting websites. This in turn requires us to obtain a fine-grained model of the web page loading process, two key components of which are the browser and the web page. After diving into the immensely complex web page loading process, we instrument the browser in order to extract bits of information as it loads a web page; this enables us to obtain the models for 50 top Alexa-ranked global websites. Following that, we build a traffic generator framework to generate network traffic according to the models. Next, we design and implement from scratch CS-Tamaraw, a congestion-sensitive version of Tamaraw, the most secure member of the BuFLO family. With all the pieces in hand, we perform live experiments to confirm that CS-Tamaraw provides the predicted gains in privacy as in the original study. However, when CS-Tamaraw is tunneled through Tor as we propose, its defense degrades significantly. We then conduct experiments to determine whether CS-Tamaraw is at fault. Both CS-Tamaraw and a simple, barebone, application-layer defense work largely as expected without Tor but are similarly afflicted when tunneled through Tor. Further investigations suggest that the unexpected results are due to artifacts in network conditions and not due to flaws in the design or implementation of CS-Tamaraw. We end after discussing the large-scale simulation studies with various levels of adoption of CS-Tamaraw

Image Retrieval with Relevance Feedback using SVM Active Learning

In content-based image retrieval, relevant feedback is studied extensively to narrow the gap between low-level image feature and high-level semantic concept. In general, relevance feedback aims to improve the retrieval performance by learning with user's judgements on the retrieval results. Despite widespread interest, but feedback related technologies are often faced with a few limitations. One of the most obvious limitations is often requiring the user to repeat a number of steps before obtaining the improved search results. This makes the process inefficient and tedious search for the online applications. In this paper, a effective feedback related scheme for content-based image retrieval is proposed. First, a decision boundary is learned via Support Vector Machine to filter the images in the database. Then, a ranking function for selecting the most informative samples will be calculated by defining a novel criterion that considers both the scores of Support Vector Machine function and similaritymetric between the "ideal query" and the images in the database. The experimental results on standard datasets have showed the effectiveness of the proposed method

KINETIC STUDY OF SYNTHESIS REACTION OF LIGNOSULFONATE USING ISOTHERMAL DIFFERENTIAL SCANNING CALORIMETRY METHOD

The kinetics of lignin methylsulfonation were studied in solution by using differential scanning calorimetry (DSC) techniques under an isothermal program, at 55, 65, 75 and 85°C, respectively. It was found that activation energy, Eα =  41.26 kJ/mol, and preexponential factor A was 1.85×103 s-1

Cast3M implementation of the extended finite element method for cohesive crack

In this paper, the finite element for cohesive crack for quasi-brittle materials is constructed by the displacement discontinuities in the element. The algorithm of construction and procedures for involving this finite element into code Cast3M are presented. The numerical calculations in fracture mechanics are presented to demonstrate the benefits of the proposed implementation

THE IMPLEMENTATION OF COMMUNICATIVE LANGUAGE TEACHING IN THE CONTEXT OF ONLINE LEARNING: A LITERATURE REVIEW

With the occurrence of the COVID-19 crisis, there has been dramatically growth and adoption of online education. As a consequence of the epidemic, institutes have been compulsory to close, and teaching and learning have changed fully to home studying. As a result, numerous educational institutions have adopted online teaching and learning on a massive scale. To combine the Communicative Language Teaching (CLT) approach with a framework of computer-assisted language learning seems to be the best strategy during a coronavirus outbreak. This study offers a survey of the literature on Communicative Language Teaching in the situation of online teaching and studying. This paper begins with an overview, definition, and characteristics of CLT. It then examines how CLT can be beneficial in a virtual classroom: advantages and disadvantages. Besides, it discusses the approaches to using CLT in online teaching and learning. This paper's goal is to provide an effective overview that can be used for online language instruction. The study will add to our understanding of Communicative Language Teaching and its use in an online setting.  Article visualizations

Tuberculosis among economic migrants: a cross-sectional study of the risk of poor treatment outcomes and impact of a treatment adherence intervention among temporary residents in an urban district in Ho Chi Minh City, Viet Nam.

BACKGROUND Tuberculosis (TB) remains a major cause of avoidable deaths. Economic migrants represent a vulnerable population due to their exposure to medical and social risk factors. These factors expose them to higher risks for TB incidence and poor treatment outcomes. METHODS This cross-sectional study evaluated WHO-defined TB treatment outcomes among economic migrants in an urban district of Ho Chi Minh City, Viet Nam. We measured the association of a patient's government-defined residency status with treatment success and loss to follow-up categories at baseline and performed a comparative interrupted time series (ITS) analysis to assess the impact of community-based adherence support on treatment outcomes. Key measures of interest of the ITS were the differences in step change (β) and post-intervention trend (β). RESULTS Short-term, inter-province migrants experienced lower treatment success (aRR = 0.95 [95% CI: 0.92-0.99], p = 0.010) and higher loss to follow-up (aOR = 1.98 [95% CI: 1.44-2.72], p  55 years of age (aRR = 0.93 [95% CI: 0.89-0.96], p < 0.001), relapse patients (aRR = 0.89 [95% CI: 0.84-0.94], p < 0.001), and retreatment patients (aRR = 0.62 [95% CI: 0.52-0.75], p < 0.001) had lower treatment success rates. TB/HIV co-infection was also associated with lower treatment success (aRR = 0.77 [95% CI: 0.73-0.82], p < 0.001) and higher loss to follow-up (aOR = 2.18 [95% CI: 1.55-3.06], p < 0.001). The provision of treatment adherence support increased treatment success (IRR(β) = 1.07 [95% CI: 1.00, 1.15], p = 0.041) and reduced loss to follow-up (IRR(β) = 0.17 [95% CI: 0.04, 0.69], p = 0.013) in the intervention districts. Loss to follow-up continued to decline throughout the post-implementation period (IRR(β) = 0.90 [95% CI: 0.83, 0.98], p = 0.019). CONCLUSIONS Economic migrants, particularly those crossing provincial borders, have higher risk of poor treatment outcomes and should be prioritized for tailored adherence support. In light of accelerating urbanization in many regions of Asia, implementation trials are needed to inform evidence-based design of strategies for this vulnerable population

A Novel Chebyshev Series Fed Linear Array with High Gain and Low Sidelobe Level for WLAN Outdoor Systems

This paper proposes a novel high gain and low sidelobe level (SLL) linear microstrip array antenna for outdoor WLAN applications. The antenna consists of two main parts, which are a linear array and a reflector. The linear array comprises of 10 elements; those have been designed on Rogers RT/Duroid 5870tm with the dimensions of 422×100×10.15 mm3. To gain low SLLs, a series fed network was designed to have the output signals being proportional to the Chebyshev distributions (with preset SLL of -30 dB). Furthermore, Yagi antenna theory has been applied by adding directors above every single element to increase the directivity of the single element. The reflector has been constructed at the back of the proposed structure. Simulation results show that the array can provide high gain of 17.5 dBi and a low SLL of -26 dB. A prototype has been fabricated and measured. Good agreements between simulation and measurement data have been obtained