Macroscopic behavior of bidisperse suspensions of noncolloidal particles in yield stress fluids

We study both experimentally and theoretically the rheological behavior of isotropic bidisperse suspensions of noncolloidal particles in yield stress fluids. We focus on materials in which noncolloidal particles interact with the suspending fluid only through hydrodynamical interactions. We observe that both the elastic modulus and yield stress of bidisperse suspensions are lower than those of monodisperse suspensions of same solid volume fraction. Moreover, we show that the dimensionless yield stress of such suspensions is linked to their dimensionless elastic modulus and to their solid volume fraction through the simple equation of Chateau et al.[J. rheol. 52, 489-506 (2008)]. We also show that the effect of the particle size heterogeneity can be described by means of a packing model developed to estimate random loose packing of assemblies of dry particles. All these observations finally allow us to propose simple closed form estimates for both the elastic modulus and the yield stress of bidisperse suspensions: while the elastic modulus is a function of the reduced volume fraction $\phi/\phi_m$ only, where $\phi_m$ is the estimated random loose packing, the yield stress is a function of both the volume fraction $\phi$ and the reduced volume fraction

HEDGE ALGEBRAS, THE SEMANTICS OF VAGUE LINGUISTIC INFORMATION AND APPLICATION PROSPECTIVE

The report aims to show that hedge algebras model actually the proper qualitative semantics of words of linguistic variables based on the argument that the inherent qualitative semantics of words should be expressed through the order relationships, induced by the word semantics, between the words in their respective variable domains, as required by decision making of human daily lives. This makes the hedge algebra based approach to the word semantics quite different from the existing approaches and become the only approach that can immediately deal with the natural qualitative semantics of words. We explain clearly and systematically distinguished features and properties of this approach to show that these seem to make the approach to be sound and ensure its effectiveness in applications. This approach seems to be promising for development of hedge algebra-based method to solve problems in various application fields. For illustration, we will give a short overview of effective results some of the initial applications of hedge algebras in the fields of knowledge based systems and in fuzzy control

Constrained Twin Variational Auto-Encoder for Intrusion Detection in IoT Systems

Intrusion detection systems (IDSs) play a critical role in protecting billions of IoT devices from malicious attacks. However, the IDSs for IoT devices face inherent challenges of IoT systems, including the heterogeneity of IoT data/devices, the high dimensionality of training data, and the imbalanced data. Moreover, the deployment of IDSs on IoT systems is challenging, and sometimes impossible, due to the limited resources such as memory/storage and computing capability of typical IoT devices. To tackle these challenges, this article proposes a novel deep neural network/architecture called Constrained Twin Variational Auto-Encoder (CTVAE) that can feed classifiers of IDSs with more separable/distinguishable and lower-dimensional representation data. Additionally, in comparison to the state-of-the-art neural networks used in IDSs, CTVAE requires less memory/storage and computing power, hence making it more suitable for IoT IDS systems. Extensive experiments with the 11 most popular IoT botnet datasets show that CTVAE can boost around 1% in terms of accuracy and Fscore in detection attack compared to the state-of-the-art machine learning and representation learning methods, whilst the running time for attack detection is lower than 2E-6 seconds and the model size is lower than 1 MB. We also further investigate various characteristics of CTVAE in the latent space and in the reconstruction representation to demonstrate its efficacy compared with current well-known methods

Effect of Polypyrrole on the Electrical, Dielectric and Mechanical Properties of Waterborne Epoxy Coatings

In this context, conducting composite based on waterborne epoxy system and polypyrrole (PPy) was investigated. The polypyrrole was synthesized by chemical oxidation polymerization. Its morphology and chemical structure were confirmed by using field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). Then, PPy was well-dispersed in the epoxy coating and had a good compatibility with the matrix. The effects of PPy on dielectric, electrical and mechanical properties of epoxy/PPy composites was examined. The dielectric constant and electrical conductivity of the coatings increased with addition of PPy fillers. Over to 15 wt. % of PPy loading, the volume resistivity of samples slightly decreased from 6.7 × 1010 to 1.5 × 1010 Ω cm. In contrast, the presence of PPy diminished both impact and abrasion resistance of the epoxy/PPy composites, down to 160 kg cm and 10.2 L/mil, respectively, but they stayed acceptable for the coatings. The results reveal that the epoxy containing polypyrrole is suitable for various electrical and dielectric applications

EVALUATION OF CITIZENS' SATISFACTION WITH THE QUALITY OF PUBLIC ADMINISTRATIVE SERVICES IN THE MEKONG DELTA, VIETNAM

Citizen satisfaction is one of the essential factors reflecting the quality of public administrative services provided by state administrative agencies. The study aims to assess citizens' satisfaction with the quality of public administrative services in the Mekong Delta, Vietnam. Research data were collected from survey results using questionnaires from 792 survey samples in the Mekong Delta, Vietnam. Research results have shown that citizens are satisfied with the quality of public administrative services in the Mekong Delta, Vietnam. At the same time, there are six factors affecting citizens' satisfaction with the quality of public administrative services, including (1) Reliability; (2) Service capacity of staff; (3) Service attitude of staff; (4) The service level of staff; (5) Infrastructure; (6) Administrative procedures. Research results show no difference in citizen satisfaction in gender, age and education groups. Besides, the survey area group has a difference in citizen satisfaction. The research results have theoretical and practical significance for public administration in Vietnam. From the research results, several contents are discussed and proposed to improve citizens' satisfaction with the quality of public administrative services in the Mekong Delta, Vietnam

HIGH PROTECTION PERFORMANCE OF COATING SYSTEMS BASED ON ZINC RICH PRIMER AND FLUOROPOLYMER COATING

Coating systems based on zinc rich primer and fluoropolymer top coat were exposed for 8 years at different atmospheric stations in Vietnam: Hanoi, Ha Long and Nha Trang. For comparison the coating system with zinc rich primer and polyurethane topcoat was also tested. The degradations of coating systems were evaluated by gloss measurement and electrochemical impedance spectroscopy. The obtained results show that coating systems with zinc rich primer and top coatings based on fluoropolymer  and polyurethane topcoats show very high weather resistance and corrosion protection performance, but the systems with fluoropolymer are better than coating system with polyurethane topcoat

Studying and forecasting the evolution of the Day river coastal zone up to the year of 2070

The Day river coastal zone is the place of plentiful and eventful economical activities and the natural habitat of diverse endemic species that should be preserved and developed. According to the updated geological, remote-sensing and oceanographic data sources, this study figures out the actual state, evolutional history and forecasts the development of the Day river coastal zone up to the year 2070, which could be used to improve the effectiveness of the long-term spatial coastal zone management and master planning. Major conclusions are as follows: (i) The Day river coastline has been highly modified since the last 50 years, (ii) The shoreline seaward development tends to gradually decrease in recent years, and (iii) The river-bed continues to be shifted southwestwards in the context of global climate change and sea level rise.Abstract STUDYING AND FORECASTING THE EVOLUTION OF THE DAY RIVER COASTAL ZONE UPTO THE YEAR 2050 Duong Quoc Hung1, Vu Hai Dang1, Phan Dong Pha1, Nguyen Thi Anh Nguyet1, Ngo Bich Huong1, Nguyen Thai Son2 (1) Institute of Marine Geology and Goephysics; (2) Institute of Geography The coastal geographical features including alluvial grouds, estuaries, mangrove forest, etc. are products of the river - ocean interactions, reflect the dynamic equilibrium of the unsustainable ecosystems that are spacial and temporary changing. These areas are also the places of plentiful and eventful economical activities and the natural diversified endemic habitats to be preserved and developed. According to the updated data sources, this study mentions to the actual state, evolution history and developing forecasts for the Day River coastal zone up to the year of 2050, which could be used to inhale the effectiveness of the long-term spacial coastal zone management and master plannin

8-hydroxyquinoline-modified clay incorporated in an epoxy coating for the corrosion protection of carbon steel

In the present work, a well-known corrosion inhibitor (8-hydroxyquinoline (8HQ)) was inserted within the montmorillonite platelets (8HQ-MMT) and the modified clay was incorporated (3 wt.%) into a solvent-free epoxy coating which was afterwards deposited on carbon steel substrates. First, the inhibitive action of 8HQ was investigated by electrochemical methods carried out on a bare carbon steel rotating disk electrode in a 0.1 M NaCl solution. Then, electrochemical impedance measurements were performed to assess the effect of the 8HQ-MMT in the epoxy coating for the corrosion protection. The results were compared with a reference sample constituted by the epoxy coating containing an ammonium quaternary salt-modified clay. It was shown that the two coatings presented good barrier properties. Dry and wet adherence measurements revealed an improvement of the adherence when the 8HQ-MMT was incorporated into the coating by comparison with the reference sample. It was concluded that the 8HQ mainly had an effect at the metal/coating interface but its concentration was too low to afford significant corrosion protection of the carbon steel

Estimating the cost of illness of acute Japanese encephalitis and sequelae care in Vietnam and Laos: a cross-sectional study

Background Japanese encephalitis (JE) is a leading cause of acute encephalitis syndrome and resulting neurological disability in Asia and the Western Pacific. This study aims to estimate the cost of acute care, initial rehabilitation and sequelae care, in Vietnam and Laos. Methodology We conducted a cross-sectional retrospective study using a micro-costing approach from the health system and household perspectives. Out-of-pocket direct medical and non-medical costs, indirect costs, and family impact were reported by patients and/or caregivers. Hospitalization costs were extracted from hospital charts. Acute costs covered expenditures from pre-hospital to follow-up visits while sequelae care costs were estimated from expenditures in the last 90 days. All costs are in 2021 US dollars. Principal findings 242 patients in two major sentinel sites in the North and South of Vietnam and 65 patients in a central hospital in Vientiane, Laos, with laboratory-confirmed JE were recruited regardless of age, sex, and ethnicity. In Vietnam, the mean total cost was $3,371 per acute JE episode (median$2,071, standard error [SE] $464) while annual costs were$404 for initial sequelae care (median $0, SE$220) and $320 for long-term sequelae care (median$0, SE $108). In Laos, the mean hospitalization costs in acute stage were$2,005 (median $1,698, SE$279) and the mean annual costs were $2,317 (median$0, SE $2,233) for initial sequelae care and$89 (median $0, SE$57) for long-term sequelae care. In both countries, most patients did not seek care for their sequelae. Families perceived extreme impact from JE and 20% to 30% of households still had sustained debts years after acute JE. Conclusions JE patients and families in Vietnam and Laos suffer extreme medical, economic, and social hardship. This has policy implications for improving JE prevention in these two JE-endemic countries