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Exact implicit Solution of Nonlinear Heat Transfer in Rectangular Straight Fin Using Symmetry Reduction Methods
Get PDFIn this paper, the exact implicit solution of the second order nonlinear ordinary differential equation which governing heat transfer in rectangular fin is obtained using symmetry reduction methods. General relationship among the temperature at the fin tip, the temperature gradient at the fin base, the mode of heat transfer, and the fin parameters and ℰ is obtained. Some numerical examples are discussed and it is shown that the temperature of fin increases when approaching from the heat source. The relationship between the fin efficiency and the temperature of fin tip is obtained for any value of the mode of heat transfer . The relationship between the fin efficiency and both the parameter and ε the temperature gradient at the fin base is obtained. To our best knowledge, solutions obtained in this paper are new
Laminar Boundary Layer Flow of Sisko Fluid
Get PDFThe problem of steady two dimensional laminar boundary layer flow of non-Newtonian fluid is analyzed in the present paper. Sisko fluid model, one of the various fluid models of non- Newtonian fluid, is considered for stress-strain relationship. Similarity and numerical solutions obtained for the defined flow problem
A new analytic numeric method solution for fractional modified epidemiological model for computer viruses
Get PDFComputer viruses are an extremely important aspect of computer security, and understanding their spread and extent is an important component of any defensive strategy. Epidemiological models have been proposed to deal with this issue, and we present one such here. We consider the modified epidemiological model for computer viruses (SAIR) proposed by J. R. C. Piqueira and V. O. Araujo. This model includes an antidotal population compartment (A) representing nodes of the network equipped with fully effective anti-virus programs. The multi-step generalized differential transform method (MSGDTM) is employed to compute an approximation to the solution of the model of fractional order. The fractional derivatives are described in the Caputo sense. Figurative comparisons between the MSGDTM and the classical fourth-order Runge-Kutta method (RK4) reveal that this method is very effective. Mathematica 9 is used to carry out the computations. Graphical results are presented and discussed quantitatively to illustrate the solution
Anaerobic 5-Hydroxybenzimidazole Formation from Aminoimidazole Ribotide: An Unanticipated Intersection of Thiamin and Vitamin B12 Biosynthesis
No full textComparative genomics of the bacterial thiamin pyrimidine synthase (thiC) revealed a paralogue of thiC (bzaF) clustered with anaerobic vitamin B12 biosynthetic genes. Here we demonstrate that BzaF is a radical S-adenosylmethionine enzyme that catalyzes the remarkable conversion of aminoimidazole ribotide (AIR) to 5-hydroxybenzimidazole (5-HBI). We identify the origin of key product atoms and propose a reaction mechanism. These studies represent the first step in solving a long-standing problem in anaerobic vitamin B12 assembly and reveal an unanticipated intersection of thiamin and vitamin B12 biosynthesis
Environmentally sustainable industrial modernization and resource consumption: Is the Hotelling\u27s rule too steep?
No full textThe suggested model describes the optimal management of a manufacturing system (a firm, region, or industry) that consumes a scarce natural resource and replaces obsolete productive assets with new resource-efficient ones. The model includes resource-saving embodied technological change, a varying resource price, and environmental quotas on resource consumption. Mathematically, it leads to the infinite-horizon optimal control of nonlinear integral equations with unknown integration limits. A steady-state analysis of the model addresses environmentally sustainable manufacturing and provides important implications for both firm and government decision-making
Tillering in the Sugary1 sweet corn is maintained by overriding the teosinte branched1 repressive signal
No full textThe evolution of apical dominance in maize during domestication from teosinte is associated with higher expression from the teosinte branched1 (tb1) gene that inhibits tiller bud outgrowth. Unlike many standard maize varieties, the sweet corn inbred P39 that carries a mutation in a starch biosynthesis gene sugary1 produces multiple tillers and providing an opportunity to explore the diversification of the tb1 signal in maize. Through gene expression analysis, we show that tiller buds in P39 continue to grow by overriding the high expression level of tb1 that arrests bud outgrowth in maize inbred B73. In addition, we demonstrate that while B73 is largely non-responsive to shade, both P39 and teosinte respond through tb1-independent and tb1-dependent molecular mechanisms, respectively, leading to inhibition of tiller bud outgrowth
Electrospun Polycaprolactone (PCL) and PCL/ nano-hydroxyapatite (PCL/nHA)-based nanofibers for bone tissue engineering application
No full textCeramic/polymer composite scaffolds have been widely investigated for repairing and regeneration of damaged bone tissues. In this report, the electrospinning technique was chosen to fabricate two different kinds of fibrous scaffolds which were Polycaprolactone (PCL) and PCL/nano-hydroxyapatite (PCL/nHA). Several characterizations such as morphologies of fibers, average diameter and water uptake property were done. Based on the results obtained, PCL/nHA fibers with the average diameters of 521.10nm exhibited good water uptake properties and were more hydrophilic than pure PCL fibers. PCL/nHA-based nanofibers could be potential in bone tissue regeneration
Effects of Chitosan Concentration on the Protein Release Behaviour of Electrospun Poly(ε -caprolactone)/Chitosan Nanofibers
No full textPoly(ε-caprolactone)/chitosan (PCL/chitosan) blend nanofibers with different ratios of chitosan were electrospun from a formic acid/acetic acid (FA/AA) solvent system. Bovine serum albumin (BSA) was used as a model protein to incorporate biochemical cues into the nanofibrous scaffolds. The morphological characteristics of PCL/chitosan and PCL/chitosan/BSA Nanofibers were investigated by scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) was used to detect the presence of polymeric ingredients and BSA in the Nanofibers. The effects of the polymer blend ratio and BSA concentration on the morphological characteristics and consequently on the BSA release pattern were evaluated. The average fiber diameter and pore size were greater in Nanofibers containing BSA. The chitosan ratio played a significant role in the BSA release profile from the PCL/chitosan/BSA blend. Nanofibrous scaffolds with higher chitosan ratios exhibited less intense bursts in the BSA release profile
Identifying contextual socio-cultural attributes as predictors of user satisfaction: A study in transformed public housings in Nigeria
No full textTransformation of houses is common, especially when households inhabit them for a considerable period of time. However, the scale of transformation might vary. Public housing in Nigeria has seen large scale transformations, and started to generate wide attention. The transformation phenomenon is often attributed to the exclusion of socio-cultural values in initial design that eventually results in unguided densification. But at the same time, house transformations arise from people’s desires to satisfy their own ever changing housing needs. Using transformation as a sign of dissatisfaction, this study was an attempt to identify local socio-cultural attributes lack of which result in such transformations. Conditional sampling was adopted in order to find respondents across Nigeria. Socio-cultural attributes were identified from background study and were used in structuring a questionnaire-based survey. Findings from univariate and psychometric analysis based on the survey indicated that social activities and family structure were the two most significant socio-cultural attributes that guide residents’ transformation decisions in public housing adjustments. This finding also appeared to be crucial as initial layouts proved not to lead to users’ satisfaction. These results might be useful for prospective developers who are explicitly seeking a successful and sustainable delivery system
Determination of withdrawal time for oxytetracycline in different types of goats for milk consumption
No full textAntibiotics are widely used in animal husbandry and the presence of antibiotics in milk is a health hazard. The objective of this study was to determine residual amounts of oxytetracycline in fresh, aged, and pasteurized milk of 3 breeds of goats using HPLC analysis. It was also essential to determine the safe withdrawal period of oxytetracycline in lactating goats. The quantitative results obtained using the HPLC system were compared with the tolerance limit of oxytetracycline in milk in the United States. Fifteen milking does, 5 Nubians, 5 Alpines, and 5 LaManchas were randomly selected from the milking herd at the International Goat Research Center at Prairie View A&M University. A simple sample preparation and isocratic HPLC method using ultraviolet detection was used for analysis of milk samples. The HPLC results indicated that the withdrawal period of oxytetracycline in treated Alpine does was 82. h (7 milking), whereas for Nubian does the period was 58. h (5 milking), and for LaManchas the period was 72. h (6 milking) after drug administration. The overall withdrawal period for all the treated goats of 3 breeds was 72. h. Although these results indicated that the depletion rate of this antibiotic was faster in goats than the reported data for cows, the 96-h withdrawal period that is currently used for lactating cows is still necessary for these 3 breeds of goats. Additionally, our results indicated that oxytetracycline is not stable in goat milk at refrigeration temperature or during pasteurization and will decrease significantly