The Potential Of Wollastonite As A New Filler For Natural Rubber Compounds

Wollastonite or calcium silicate, (CaSiO3) has potential as a new type of filler in natural rubber (NR) compounds. The curing characteristics, mechanical properties, swelling behavior, thermal stability and morphology of wollastonite filled NR compounds were investigated. Four series of experiments were performed. All NR compounds were prepared using a two roll mill with different filler loading from 0 to 40 phr. In the first series, the effects of different wollastonite loading on the properties of NR compounds were studied. Results indicated that the cure time (t90), scorch time (ts2), tensile strength and elongation at break (Eb) decreased, whereas, maximum torque (MH), tensile modulus, hardness, thermal stability and swelling behavior increased with wollastonite loading. The second series, the effect of physical ball mill treated wollastonite on the properties of NR compounds was investigated. Treated wollastonite improved the properties of NR compounds as compared to untreated wollastonite. The third series, the effect of 1 phr of 3- aminopropyltriethoxysilane (APTES) as silane coupling agent was studied. The presence of APTES showed an improvement in the properties of NR compounds. This was due to the presence of APTES, which enhanced the rubber-filler interaction of NR compounds. In the last series, the influence of partial replacement of wollastonite by carbon black or calcium carbonate was investigated. The substitution of wollastonite by commercial fillers have improved the properties of NR compounds

INVESTIGATION OF INENZYME TREATMENTS TO ASSIST EXTRACTION OF ESSENTIAL OIL FROM THE LEAVES AND BRANCHES OF CINNAMOMUM CASSIA COLLECTED IN YEN BAI PROVINCE

In order to improve the efficiency of essential oil distillation of the leaves and branchesfrom the cassia plant (Cinnamomum cassia (L.) J. Presl) growing in Yen Bai province, theeffects of enzyme treatments of the plant materials before distillation were investigated usingcrude laccase obtained from culture medium of the fungus Ganoderma lucidum and Cellic Htech2 (Novozymes, Denmark), a multienzyme system consisting of cellulase and xylanase. Theresults showed that enzyme treatments increased oil yield and shorten distillation time. The useof a mixture of both enzyme systems was more effective than using them separately. Underoptimal conditions, an increase in oil yield of 41.7 % was achieved, while distillation time wasshortened from 8 to 5 hours. The enzyme treatments did not change the qualitative compositionof the essential oils. However, significant changes in the percentages of cinnamic aldehyde(69.74 % to 85.6 %) and cinnamyl acetate (17.2 % to 1.34 %) were observed

Predicting Information Diffusion on Twitter - Analysis of predictive features

Information propagation on online social network focuses much attention in various domains as varied as politics, fact checking, or marketing. Modeling information diffusion in such growing communication media is crucial in order both to understand information propagation and to better control it. Our research aims at predicting whether a post is going to be forwarded or not. Moreover, we aim at predicting how much it is going to be diffused. Our model is based on three types of features: user-based, time-based and content-based. Using three collections corresponding to a total of about 16 millions of tweets, we show that our model improves of about 5% F-measure compared to the state of the art, both when predicting if a tweet is going to be re-tweeted and when predicting how popular it will be. F-measure in our model is between 70% and 82%, depending on the collection. We also show that some features we introduced are very important to predict retweetability such as the numbers of followers and number of communities that a user belongs to. Our contribution in this paper is twofold: firstly we defined new features to represent tweets in order to predict their possible propagation; secondly we evaluate the model we built on top of both features from the literature and features we defined on three collections and show the usefulness of our features in the prediction

Influences of the compressibility on aerodynamic characteristics of profile under the transonic flow theory

Transonic flows are complex problems. At certain Mach numbers, in gas flows there are local transitions from the subsonic into the supersonic and reciprocally, especially the discontinuity throughout shock waves. Subsonic flows and supersonic flows have very different properties, thus calculation methods are also different-the subsonic equation is elliptic and the supersonic equation is hyperbolic. Using established programs (based on the incompressible theory, the compressible theory and the transonic theory), we studied sub-transonic flow characteristics with variations of the Mach number. Our studies are also carried out with variations of incidence, which impact on t he transonic effect. Numerical results show that the local compressibility depends on not only the speed but also the incidence. At a rather great angle of attack, local supersonic regions can appear with free Mach numbers in the order of 0.3 - the Mach number is normally considered as a speed of incompressible flows. According to these results, we can recognize for which regime the local compressibility of flow is considerable and then it is necessary to consider the problem under the transonic flow theory

Types of momentum defect diffusion at the begining of the wake and wake establishment zone for the coupled wake and comparison with the isolated wake

The article [10] has presented the necessity of the classification into two types: Isolated wakes and coupled wakes. In this report, different types of momentum defect diffusion at the beginning of wake are analyzed for the two types of coupled wake and isolated wake. According to ·numerical results obtained, we analyses the existence - long or short - of the wake establishment zone before the wake established zone, and this zone is very different between isolated wake and coupled wake

The pedagogical training management of gifted high school teachers in the region of Red River Delta based on a competency approach

Pedagogical training for teachers is always an important issue of every education system. Teachers impart knowledge, give academic advice to students, and assist students in applying knowledge to develop society. This study investigated the gifted high school teacher pedagogical training management in the region of the Red River Delta according to the competency approach. Based on the available data, the research indicated three main things: (i) Professional pedagogical competence of gifted high school teachers; (ii) Pedagogical training activities for gifted high school teachers; (iii) Management of pedagogical training activities for gifted high school teachers. This study conducted a survey of 547 departmental and school managers in gifted high school teachers in nine provinces in Red River Delta, including Hanoi, Ha Nam, Thai Binh, Nam Dinh, Hai Duong, Hung Yen, Bac Ninh, Quang Ninh, and Vinh Phuc. These findings are only preliminary research, and they will be an important basis for proposing management solutions to improve the effectiveness of pedagogical training activities for gifted high school teachers

Predicting Information Diffusion on Twitter - Analysis of predictive features

Information propagation on online social network focuses much attention in various domains as varied as politics, fact checking, or marketing. Modeling information diffusion in such growing communication media is crucial in order both to understand information propagation and to better control it. Our research aims at predicting whether a post is going to be forwarded or not. Moreover, we aim at predicting how much it is going to be diffused. Our model is based on three types of features: user-based, time-based and content-based. Using three collections corresponding to a total of about 16 millions of tweets, we show that our model improves of about 5% F-measure compared to the state of the art, both when predicting if a tweet is going to be re-tweeted and when predicting how popular it will be. F-measure in our model is between 70% and 82%, depending on the collection. We also show that some features we introduced are very important to predict retweetability such as the numbers of followers and number of communities that a user belongs to. Our contribution in this paper is twofold: firstly we defined new features to represent tweets in order to predict their possible propagation; secondly we evaluate the model we built on top of both features from the literature and features we defined on three collections and show the usefulness of our features in the prediction

Extraction de Localisations dans les MicroBlogs

La circulation de l’information est de plus en plus rapide. Les applications comme WhatsApp ou Twitter permettent d’échanger des informations sur des évènements de façon quasi instantanée. Il s’agit de ressources précieuses desquelles peuvent être extraites des informations sur des événements (temps, localisation ou entité concernée). Nous nous centrons ici sur l’aspect localisation qui a de nombreuses applications aussi bien dans le cadre d’outils géospatialisés que pour des recommandations personnalisées. Dans le contexte de microblogs, les outils développés en traitement du langage naturel ne sont pas suffisants compte tenu de la forme des messages; par exemple les tweets ne sont pas linguistiquement corrects. Par ailleurs, le nombre important de messages à traiter est également un challenge. Dans ce article, nous présentons un modèle pour prédire si un microblog (tweet) contient une localisation ou non et nous montrons que cette prédiction améliore l’efficacité de l’extraction de localisations des tweets

Determinants Influencing Accounting Quality of Transportation Service Firms

The study aimed to determine what determinants influencing the accounting of transportation service firms working the area of Da Nang of Vietnam. A study model was developed, investigated and analyzed with the involvement of 250 transportation service firms in Da Nang. The results show five determinants influencing the accounting works including industry characteristics; legal guidance; material facilities for accounting; interest in accounting of business owners; accountants’ qualifications. Among them, the two most important determinants influencing the quality of the accounting were legal guidance and interest in accounting of business owners. Based on the findings, some recommendations were made to improve the quality of accounting of transportation service firms. Keywords: Determinants, accounting, transportation services DOI: 10.7176/RJFA/11-4-08 Publication date: February 29th 202