1,229 research outputs found

    Approximate Solution of Nonlinear fractional Integro-Di erential Equations By He's Homotopy Perturbation Method And The Modi cation of He's Variational Iteration Method

    Get PDF
    In this paper, we compare the modi cation of He's variational iteration method (MVIM), and He's homotopy perturbation method (HPM), in order to obtain the approximate solution of nonlinear frac- tional integro-di erential equations of Volterra and Fredholm integro-di erential equations, we present some examples to nd out accuracy of the methods. keywords: Fractional integro-di erential equations, Caputo derivative, modi cation of He's variational iteration method, homotopy perturbation metho

    Methomyl Adsorption onto Cotton Stalks Activated Carbon (CSAC): Equilibrium and Process Design

    Get PDF
    AbstractEquilibrium studies were carried out for adsorption of an insecticide (Methomyl) form aqueous solutions onto a prepared cotton stack activated carbon (CTAC) in a batch adsorption system. Parameters affecting adsorption capacity including contact time, adsorbent size (dp =355:800μm) and temperature (T=25:60°C) were investigated. Three mathematical models, Langmuir, Freundlich and Redlich-Peterson were employed for fitting the equilibrium data. Linear regression was used to determine the best fit and was found that the equilibrium data are best represented by Langmuir model thus suggesting the monolayer sorption of methomyl. The Langmuir constants (qmax = KL/aL) decreases with the increasing of temperature as well as decreasing the particle size of adsorbent. The adsorption capacity was found 72.85 mg/g at 25°C and decreased to 47.36 mg/g when temperature increased to 60°C . The value of enthalpy change was calculated (H = -2.35 kJ/mol) indicating that the removal process was exothermic and physical in nature. A single stage batch adsorber was designed for the adsorption of methomyl onto CSAC based on the optimum isotherm

    Les deux usages des orthographes approchées : approche méthodologique et pratique enseignante

    Get PDF
    RĂ©sumĂ© Le prĂ©sent article constitue une note de synthèse qui porte sur la prĂ©sentation des orientations didactiques qui sont susceptibles d’amĂ©liorer et de soutenir l’enseignement-apprentissage de l’écrit. L’objectif de cet article est de prĂ©senter la dĂ©marche didactique des orthographes approchĂ©es ainsi que son importance en tant que stratĂ©gie qui favorise l’apprentissage de l’écrit et en tant qu’approche mĂ©thodologique permettant aux chercheurs de suivre l’évolution de l’écrit chez les Ă©lèves. Cette mĂ©thode permet aux enseignants de bien s’adapter aux diffĂ©rences individuelles des Ă©lèves et de mieux suivre leur cheminement cognitif lors des situations d’orthographes approchĂ©es.   Mots-clĂ©s : orthographes approchĂ©es, approche mĂ©thodologique, pratique enseignante, enseignement-apprentissage de l’écri

    Holograms in Optical Wireless Communications

    Get PDF
    Adaptive beam steering in optical wireless communication (OWC) system has been shown to offer performance enhancements over traditional OWC systems. However, an increase in the computational cost is incurred. In this chapter, we introduce a fast hologram selection technique to speed up the adaptation process. We propose a fast delay, angle and power adaptive holograms (FDAPA-Holograms) approach based on a divide and conquer methodology and evaluate it with angle diversity receivers in a mobile optical wireless (OW) system. The fast and efficient fully adaptive FDAPA-Holograms system can improve the receiver signal to noise ratio (SNR) and reduce the required time to estimate the position of the receiver. The adaptation techniques (angle, power and delay) offer a degree of freedom in the system design. The proposed system FDAPA-Holograms is able to achieve high data rate of 5 Gb/s with full mobility. Simulation results show that the proposed 5 Gb/s FDAPA-Holograms achieves around 13 dB SNR under mobility and under eye safety regulations. Furthermore, a fast divide and conquer search algorithm is introduced to find the optimum hologram as well as to reduce the computation time. The proposed system (FDAPA-Holograms) reduces the computation time required to find the best hologram location from 64 ms using conventional adaptive system to around 14 ms

    Uplink Design in VLC Systems with IR Sources and Beam Steering

    Get PDF
    The need for high-speed local area networks to meet the recent developments in multimedia and video transmission applications has recently focused interest on visible light communication (VLC) systems. Although VLC systems provide lighting and communications simultaneously from light emitting diodes, LEDs, the uplink channel design in such a system is a challenging task. In this paper, we propose a solution in which the uplink challenge in indoor VLC is resolved by the use of an Infrared (IR) link. We introduce a novel fast adaptive beam steering IR system (FABS-IR) to improve the uplink performance at high data rates while providing security for applications. The goal of our proposed system is to enhance the received optical power signal, speed up the adaptation process and mitigate the channel delay spread when the system operates at a high transmission rate. The channel delay spread is minimised from 0.22 ns given by hybrid diffuse IR link to almost 0.07 ns. At 2.5 Gb/s, our results show that the imaging FABS-IR system accomplished about 11.7 dB signal to noise ratio (SNR) in the presence of multipath dispersion, receiver noise and transmitter mobility

    Distribution, prevalence and intensity of protozoan and monogenean parasites of carp fingerlings in selected nursery ponds

    Get PDF
    An experiment was carried out on the distribution, prevalence and intensity of infestation of protozoan and monogenean parasites of carp fingerlings in two selected areas of Bangladesh. Six hundred and forty fingerlings of seven species viz. Catla calla, Hypophthalmicthys molitrix, Labeo rohita, Ctenophalyngodon idella, Cyprinus carpio, Barbodes gonionotus and Cirrhinus cirrhosus from different nursery ponds of Shambhuganj, Mymensingh, and Santaher, Bogra were examined during this investigation. This study revealed that carp fingerlings carried a large number of protozoan and monogenean parasites. Different protozoan parasites viz Trichodina domerguei, Trichodina reticulata, Myxobolus koi, Chilodonella cyprini and monogenean parasites such as Dactylogyrus extensus, Dactylogyrus catlarius and Dactylogyroides tripathi were identified in the experimental fishes throughout the study period. It has been observed that distribution, prevalence and intensity of parasite in carp fingerlings are species and zone specific. In case of C. cirrhosus, the highest prevalence of protozoan parasite viz Trichodina domerguei were 93.75% and 75.92% in Santhahar and Shambhuganj area respectively. Irrespective of host, the most prevalent ectoparasite was Dactylogyrus extensus, followed by Myxobolus koi, Chilodonella cyprini and Dactylogyroides tripathi. Relatively higher mortality of carp fingerlings was found at younger stage. The highest prevalent parasitic species was identified as Trichodina domerguei followed by Trichodina reticulata and Dactylogyrus catlarius were found 93.75% in Cirrhinus cirrhosus, 68.75% in Cyprinus carpio and 39.44% in Hypophthalmicthys molitrix respectively

    Vaginal carriage and antibiotic susceptibility profile of group B Streptococcus during late pregnancy in Ismailia, Egypt

    Get PDF
    SummaryGroup B Streptococcus (GBS) infection has long been recognized as a frequent cause of morbidity and mortality in newborn infants. The purpose of this study was to determine the colonization rate with GBS and the antibiotic susceptibility profile in pregnant women attending Gynecological clinics in Egypt. One-hundred and fifty vaginal swabs were collected from pregnant women at 35–40 weeks of gestation. In comparison to culture, direct latex agglutination testing revealed 100% sensitivity and 93.75% specificity. Thirty-eight specimens (25.3%) were found to be positive for GBS. Each isolate was tested for susceptibility to penicillin G, ampicillin, cefotaxime, erythromycin, clindamycin and vancomycin. Erythromycin-resistant isolates were further classified by double-disk method. All isolates were susceptible to penicillin G, ampicillin and vancomycin. Resistance to cefotaxime was detected in three isolates (7.89%). Five isolates (13.15%) were resistant to erythromycin and nine isolates (23.68%) were resistant to clindamycin. Four (80%) isolates had constitutive macrolide–lincosamide–StreptograminB resistance (cMLSBB) resistance and one (20%) isolate had inducible resistance (iMLSB) resistance. GBS colonization was found to be high in our region. Latex agglutination testing and Islam medium are reliable methods to detect GBS in late pregnancy; however, latex agglutination test is rapid and simpler. Penicillin G remains the first choice antibiotic for treatment of GBS infections

    Duodenal biopsies for the diagnosis of coeliac disease: are we adhering to current guidance?

    Get PDF
    Background: The British Society of Gastroenterology guidelines recommend taking at least four duodenal biopsy specimens at the time of upper gastrointestinal (UGI) endoscopy if coeliac disease (CD) is suspected and it has been shown to increase the diagnostic yield of CD. We assessed the compliance to these guidelines within our institution. We then applied measures to improve our compliance rate and assessed the resulting impact on our diagnostic rate of CD. Methods: We performed a retrospective audit of electronic records for all patients, with no prior diagnosis of CD, who underwent UGI endoscopy with duodenal biopsies between August 2014 and May 2015. We implemented measures to raise awareness among endoscopy users at our institution and carried out a reaudit between February and May 2016. Results: 924 patients were found to be eligible in the first part of the study and 278 in the second part. The proportion of patients who had ≥4 biopsy specimens submitted increased from 21.9% to 60.8% (p<0.001). The diagnostic rate of CD increased from 3.5% in the audit group to 7.6% in the reaudit group (p=0.004). A positive serology result and suspected CD as an indication for biopsy were found to be independent predictors of the likelihood of complying with guidelines. Conclusions: Our study suggests that taking <4 duodenal biopsy specimens to assess for the presence of CD may lead to the diagnosis of CD being missed. Simple measures can improve the local compliance rate to current guidelines

    Mono- and polyculture of silver barb (Puntius gonionotus) in deepwater rice systems in Bangladesh

    Get PDF
    Experiments with fish enclosures were conducted at the Deepwater Rice Farming Systems Research Site at Shuvullah, Mirzapur, Bangladesh. The objective was to study the performance of silver barb (Puntius gonionotus) called Thai sharputi or rajputi in Bangladesh in mono-and-polyculture with grass carp (Ctenopharyngodon idella), common carp (Cyprinus carpio), catla (Catla catla) and rohu (Labeo rohita). Each enclosure measured 21 m x 21 m with an approximate net height of 3.5 m. The stocking densities per cubic meter were 1 fingerling for Thai sharputi monoculture (enclosure 1), and 2 fingerlings for the polyculture systems (enclosure 2 and 3). The species ratio for enclosure 2 was 0.37:0.27:0.02:0.34 (grass carp:Thai sharputi:common carp:catla) and for enclosure 3, 0.4:0.4:0.2 (catla:rohu:Thai sharputi). In monoculture (enclosure 1), Thai sharputi performed well. This relatively good production was mainly attributed to the use of appropriately sized fingerlings and rapid growth from consumption of an abundant supply of azolla in addition to feed given. For the polyculture in enclosure 2, the average weight gain of common carp was the highest (673 g) followed by grass carp (475 g) and Thai sharputi (286 g). For the polyculture in enclosure 3, the length and weight gains for Thai sharputi were almost the same as for the monoculture
    • …
    corecore