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A Review on the Flammability and Flame Retardant Properties of Natural Fibers and Polymer Matrix Based Composites

  • Prabhakar, M.N.;Shah, Atta Ur Rehaman;Song, Jung-Il
    • Composites Research
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    • v.28 no.2
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    • pp.29-39
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    • 2015
  • Natural fibers reinforced polymer composites are being used in several low strength applications. More research is going on to improve their mechanical and interface properties for structural applications. However, these composites have serious issues regarding flammability, which are not being focused broadly. A limited amount of literature has been published on the flame retardant techniques and flammability factor of natural fibers based polymer matrix composites. Therefore, it is needed to address the flammability properties of natural fibers based polymer composites to expand their application area. This paper summarizes some of the recent literature published on the subject of flammability and flame retardant methods applied to natural fibers reinforced polymer matrix composites. Different factors affecting the flammability, flame retardant solutions, mechanisms and characterization techniques have been discussed in detail.

Empirical variogram for achieving the best valid variogram

  • Mahdi, Esam;Abuzaid, Ali H.;Atta, Abdu M.A.
    • Communications for Statistical Applications and Methods
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    • v.27 no.5
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    • pp.547-568
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    • 2020
  • Modeling the statistical autocorrelations in spatial data is often achieved through the estimation of the variograms, where the selection of the appropriate valid variogram model, especially for small samples, is crucial for achieving precise spatial prediction results from kriging interpolations. To estimate such a variogram, we traditionally start by computing the empirical variogram (traditional Matheron or robust Cressie-Hawkins or kernel-based nonparametric approaches). In this article, we conduct numerical studies comparing the performance of these empirical variograms. In most situations, the nonparametric empirical variable nearest-neighbor (VNN) showed better performance than its competitors (Matheron, Cressie-Hawkins, and Nadaraya-Watson). The analysis of the spatial groundwater dataset used in this article suggests that the wave variogram model, with hole effect structure, fitted to the empirical VNN variogram is the most appropriate choice. This selected variogram is used with the ordinary kriging model to produce the predicted pollution map of the nitrate concentrations in groundwater dataset.

O-Acetyljervine;A New $\beta-adrenoceptor$ agonist from veratrum album

  • Anwar-H. Gilani;Khalid-Aftab;S.A. Saeed;Rahat-A. Ali;Rahman, Atta-ur
    • Archives of Pharmacal Research
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    • v.18 no.2
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    • pp.129-132
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    • 1995
  • Intravenous administration of O-acetyliervine (an alkaloid from Vertrum album) produced a dose-dependent (10-100 .mu.g/kg) fall in blood pressure and tachycardia in anaesthetized normotensive rats. Pretreatment of animals with propranolol (1mg/kg) abolished these cardiovascular responses of O-acetyljervine similar to that of isoprenaline $(1\mu/ml)$. In isolated tissue experiments, O-acetyljervine $(10-100\mu/ml)$ produced a dose-dependent relaxation of phenylephrine-induced contraction of the rabbit aorta. In guinea-pig spontaneously beating atria, it caused positive inotropic and chronotorpic responses in a dose-dependent fashion $(10-100\mu/ml)$. These responses were abolished in the presence of propranolol $(1\mu/ml)$ similar to that of isoprenaline. These results indicate that O-accetyljervine is adrenoceptor stimulant $(\beta_1\; and\;beta_2)$ like isoprenaline.

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SYN Flood DoS Detection System Using Time Dependent Finite Automata

  • Noura AlDossary;Sarah AlQahtani;Reem Alzaher;Atta-ur-Rahman
    • International Journal of Computer Science & Network Security
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    • v.23 no.6
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    • pp.147-154
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    • 2023
  • Network intrusion refers to any unauthorized penetration or activity on a computer network. This upsets the confidentiality, integrity, and availability of the network system. One of the major threats to any system's availability is a Denial-of-Service (DoS) attack, which is intended to deny a legitimate user access to resources. Therefore, due to the complexity of DoS attacks, it is increasingly important to abstract and describe these attacks in a way that will be effectively detected. The automaton theory is used in this paper to implement a SYN Flood detection system based on Time-Dependent Finite Automata (TDFA).

A STUDY ON MILNE-TYPE INEQUALITIES FOR A SPECIFIC FRACTIONAL INTEGRAL OPERATOR WITH APPLICATIONS

  • Arslan Munir;Ather Qayyum;Laxmi Rathour;Gulnaz Atta;Siti Suzlin Supadi;Usman Ali
    • Korean Journal of Mathematics
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    • v.32 no.2
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    • pp.297-314
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    • 2024
  • Fractional integral operators have been studied extensively in the last few decades by various mathematicians, because it plays a vital role in the developments of new inequalities. The main goal of the current study is to establish some new Milne-type inequalities by using the special type of fractional integral operator i.e Caputo Fabrizio operator. Additionally, generalization of these developed Milne-type inequalities for s-convex function are also given. Furthermore, applications to some special means, quadrature formula, and q-digamma functions are presented.

Diet-Right: A Smart Food Recommendation System

  • Rehman, Faisal;Khalid, Osman;Haq, Nuhman ul;Khan, Atta ur Rehman;Bilal, Kashif;Madani, Sajjad A.
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.6
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    • pp.2910-2925
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    • 2017
  • Inadequate and inappropriate intake of food is known to cause various health issues and diseases. Due to lack of concise information about healthy diet, people have to rely on medicines instead of taking preventive measures in food intake. Due to diversity in food components and large number of dietary sources, it is challenging to perform real-time selection of diet patterns that must fulfill one's nutrition needs. Particularly, selection of proper diet is critical for patients suffering from various diseases. In this article, we highlight the issue of selection of proper diet that must fulfill patients' nutrition requirements. To address this issue, we present a cloud based food recommendation system, called Diet-Right, for dietary recommendations based on users' pathological reports. The model uses ant colony algorithm to generate optimal food list and recommends suitable foods according to the values of pathological reports. Diet-Right can play a vital role in controlling various diseases. The experimental results show that compared to single node execution, the convergence time of parallel execution on cloud is approximately 12 times lower. Moreover, adequate accuracy is attainable by increasing the number of ants.

Endoscopic Ultrasound Staging of Upper Gastrointestinal Malignancies

  • Saadany, Sherif El;Mayah, Wael;Kalla, Ferial El;Atta, Tawfik
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.5
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    • pp.2361-2367
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    • 2016
  • Since 1980, endoscopic ultrasound (EUS) has been used as an important tool for the evaluation of malignant diseases in hollow viscus and bilio-pancreas, as well as sub-epithelial tumors. The high-resolution capacity and low penetration depth of EUS make it possible to obtain highly detailed images of the gastrointestinal wall and immediate surroundings to a depth of 4-5 cm. Thus, over the past 35 years, EUS succeeded to modify management in significant number of cases and is now considered a gold standard tool for many gastrointestinal diseases, especially in the pancreatico-biliary tract, and adjuvant needle insertion now allows access to remote lesions that were difficult to reach in the past. With the growing spectrum of indications, tissue sampling for diagnostic purposes has become common. In this review, we aim to highlight the expanding spectrum of EUS indications and uses in staging of upper gastrointestinal malignancies, especially esophageal, gastric and ampullary tumors.

Characterization of Fracture Toughness and Wear Behavior for Plasma Ceramic Coated Materials (플라즈마 코팅재료의 파괴인성과 마모 거동)

  • Ha, Sun-Ho;Lee, Dong-Woo;Rehman, Atta Ur;Wasy, Abdul;Song, Jung-Il
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.12 no.4
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    • pp.123-130
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    • 2013
  • Zirconia is well known in industrial applications for its mechanical characteristics. DLC (diamond-like carbon) have high elastic modulus, high electric resistivity, high dielectric constant, high wear resistance, low friction coefficient, bio compatibility, chemically inert and thermally stable. Because of all these physical and chemical properties these types of coatings have become key procedure for thin coating. Friction coefficient of DLC films is already evaluated and the current work is a further advancement by calculating the fracture toughness and wear resistance of these coatings. In the present study DLC thin film coatings are developed on $ZrO_2$ alloy surface using Plasma Enhanced Chemical Vapor Deposition (PECVD) method. Vicker hardness test is employed and it was concluded that, DLC coatings increase the Vickers hardness of ceramics.

Field Evaluation of Mungbean Recombinant Inbred Lines against Mungbean Yellow Mosaic Disease Using New Disease Scale in Thailand

  • Akhtar, Khalid P.;Kitsanachandee, R.;Srinives, P.;Abbas, G.;Asghar, M.J.;Shah, T.M.;Atta, B.M.;Chatchawankanphanich, O.;Sarwar, G.;Ahmad, M.;Sarwar, N.
    • The Plant Pathology Journal
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    • v.25 no.4
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    • pp.422-428
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    • 2009
  • Studies were conducted to identify the sources of resistance in mungbean recombinant inbred lines (RILs) in Thailand against mungbean yellow mosaic disease (MYMD). 146 mungbean RILs in $F_8$ series were evaluated in a field including resistant parent NM-10-12-1 and susceptible parent KPS 2 during summer 2008 under high inoculum pressure. The RILs were subsequently scored for disease symptom severity ratings (DSSR) using a new scale. Observations regarding DSSR and % disease index (%DI) showed that the tested RILs responded differently to the disease. A large number of RILs (132) were found highly susceptible, 12 were susceptible, 3 were tolerant and one was resistant. Overall screening results showed that three RILs, viz. line no. 30, 100 and 101 had minimum DSSR and % disease index thus they are good source of resistance to MYMD in spite of high disease pressure and can therefore be used directly as varieties to manage the disease in Thailand.

Mass Fragmentation Patterns as Fingerprints for Positive Identification of Polyphenolic Compounds in a Crude Extract

  • Manshoor, Nurhuda;Weber, Jean-Frederic F.
    • Mass Spectrometry Letters
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    • v.6 no.4
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    • pp.105-111
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    • 2015
  • Sixteen compounds of Neobalanocarpus heimii were successfully identified directly from their plant extract using a triple quadrupole LC-MS/MS system. In order to fulfil the objectives of this work, a series of stilbene oligomers of various degrees of condensation were isolated and their structure are characterized. Out of these, four are resveratrol dimers, three trimers, and nine tetramers. The isolation process was done on a fully automated semi-preparative HPLC system. Their structures were elucidated on the basis of 1D- and 2D-NMR as well as MS data. The mass fragmentation patterns of the compounds were recorded and a retrievable in-house library was built to keep the data. In order to demonstrate the potential of this approach, the polyphenolic crude extract was analysed with the LC-MS/MS system and the MS/MS spectra extracted for each chromatographic peak of interest. The fragmentation patterns were compared with those of anticipated pure compounds that were previously recorded. All compounds were successfully identified. It is therefore believed that the LC-MS/MS potential for dereplication of structurally similar compounds in a crude mixture was thus firmly established.