A modified fifth-order WENO scheme for hyperbolic conservation laws

This paper deals with a new fifth-order weighted essentially non-oscillatory (WENO) scheme improving the WENO-NS and WENO-P methods which are introduced in Ha et al. J. Comput. Phys. (2013) and Kim et al., J. Sci. Comput. (2016) respectively. These two schemes provide the fifth-order accuracy at the critical points where the first derivatives vanish but the second derivatives are non-zero. In this paper, we have presented a scheme by defining a new global-smoothness indicator which shows an improved behavior over the solution to the WENO-NS and WENO-P schemes and the proposed scheme attains optimal approximation order, even at the critical points where the first and second derivatives vanish but the third derivatives are non-zero.Comment: 23 pages, 14 figure

Xylo-Oligosaccharides Production from Corn Fiber and In-Vitro Evaluation for Prebiotic Effect

Xylooligosaccharides (XOS) are considered to be prebiotics. Prebiotics are defined as non-digestible food ingredients that benefit the host by stimulating the growth and activity of a limited number of bacteria, such as the Bifidobacterium genus, in the colon. Corn fiber separated from distillers dried grains with solubles (DDGS) could be a valuable feedstock for XOS production. The objective of the first chapter was to determine the efficacy for autohydrolysis to produce XOS using fiber separated from DDGS. Fiber was treated with deionized water in a Parr-reactor, at temperatures ranging from 140 to 220 °C to produce XOS. The maximum total yield of XOS in the solution was 18.6 wt% of the corn fiber at 180 °C. The objective of the second chapter was to evaluate and compare the prebiotic effect of XOS produced by autohydrolysis of DDGS fiber (XOS-D) with other substrates (FOS, commercial XOS (XOS-C), xylose, glucose and inulin) on intestinal bacteria, B. adolescentis, B. breve and Lactobacillus brevis. Bacterial growth on XOS-C was comparable with growth on FOS and inulin. XOS-D promoted bacterial growth more than that of control. Prebiotic potential of XOS produced from corn fiber was confirmed. The objective of third chapter is to determine the yield of XOS from corn fiber separated from ground corn flour (FC) and DDGS (FD) at different autohydrolysis temperatures and hold-times. The conditions for maximum XOS production for FD and FC were 180 °C with 20 min hold-time and 190 °C with 10 min hold-time, respectively. The fourth chapter focuses on production of XOS by enzymatic hydrolysis method for XOS production. Endo-1-4-xylanase enzyme was ineffective for corn fiber as well as corn fiber gum (CFG), despite evaluating a multitude of pretreatment methods and processing conditions. We have proposed use of Multifect Pectinase PE and Multifect Xylanase enzymes, based on work from other researchers. For commercial applications such as food industries, XOS would need to be isolated from liquor. The fifth chapter of this study focuses on literature review of purification methods used in XOS purification

Methodology to Derive Resource Aware Context Adaptable Architectures for Field Programmable Gate Arrays

The design of a common architecture that can support multiple data-flow patterns (or contexts) embedded in complex control flow structures, in applications like multimedia processing, is particularly challenging when the target platform is a Field Programmable Gate Array (FPGA) with a heterogeneous mixture of device primitives. This thesis presents scheduling and mapping algorithms that use a novel area cost metric to generate resource aware context adaptable architectures. Results of a rigorous analysis of the methodology on multiple test cases are presented. Results are compared against published techniques and show an area savings and execution time savings of 46% each

Experimental characterization and mean line modelling of twin-entry and dual-volute turbines working under different admission conditions with steady flow

[ES] A pesar de la importancia de las turbinas radiales de doble entrada y doble voluta en el flujo para motores turboalimentados, sus mapas característicos y su modelado totalmente predictivo utilizando códigos dinámicos de gas 1D aún no están bien establecidos. La complejidad del flujo no estacionario y la admisión desigual de estas turbinas, cuando funcionan con pulsos de gases de escape del motor, las convierte en un sistema desafiante. Principalmente debido a la admisión de flujo desigual, se introduce un grado adicional de libertad con respecto a las turbinas conocidas como de una sola entrada con o sin álabes en el estator. Además, la adición de la segunda entrada a la voluta de la turbina aporta una complejidad adicional para determinar los parámetros de rendimiento de la turbina en estacionario estable y en condiciones de admisión desiguales.Esta tesis tiene como novedad principal un procedimiento simple para caracterizar experimentalmente y elaborar mapas característicos de estas turbinas con condiciones de flujo desiguales. Este método de análisis permite interpolar fácilmente dentro de los mapas distintivos propuestos o ajustar modelos simples y convincentes para calcular y extrapolar parámetros de rendimiento completo de turbinas de doble entrada y doble voluta. También hemos descrito aquí, dos modelos innovadores de línea media 0D que requieren una cantidad mínima de datos experimentales para calibrar ambos: es decir, el modelo de parámetros de flujo másico y el modelo de eficiencia isentrópica. Ambos modelos son predictivos en condiciones de admisión de flujo parcial o desigual utilizando como entradas: la relación de flujo másico entre ramas; la relación de temperatura total entre ramas; la relación de velocidad de álabe a chorro en cada rama y la relación de presión en cada rama. Estas cinco entradas generalmente son proporcionadas instantáneamente por códigos de dinámica de gas 1D. Por lo tanto, la novedad del modelo es su capacidad de ser utilizado de manera casi constante para la predicción del rendimiento de las turbinas de doble entrada y de doble voluta. Esto se puede lograr instantáneamente ya que las turbinas se calculan en condiciones de flujo pulsante y desigual en motores turbo alimentados. Además, se muestra una metodología para caracterizar el coeficiente de descarga de una válvula de alivio de presión. Para estimar el flujo de gas por la válvula de alivio en modelos unidimensionales, se correlaciona y valida un modelo empírico. Finalmente, se ha elaborado un mapa óptimo del coeficiente de descarga a través del método de interpolación, que puede integrarse en el sistema de modelo de motor turboalimentado completo unidimensional, para calcular el flujo másico real a través de la válvula de descarga y las válvulas de conexión de desplazamiento. Finalmente, los modelos han sido completamente validados al acoplarlos con un software de modelado unidimensional que simula tanto el banco de gas como el motor completo. Por un lado, los resultados de las validaciones del banco de gas muestran que el modelo puede predecir bien todas las variables de flujo estacionario. Por otro lado, los resultados de la validación de todo el motor muestran que el modelo es capaz de producir todas las variables del motor a plena carga como el flujo de masa de aire y el par de frenado con un buen grado de acuerdo con los datos experimentales.[EN] Despite the importance of radial in-flow twin-entry and dual-volute turbines for turbocharged engines, their characteristic maps and fully predictive modelling using 1D gas dynamic codes are not well established yet. The complexity of the un-steady flow and the unequal admission of these turbines, when operating with pulses of engine exhaust gas, make them a challenging system. Mainly due to the unequal flow admission, an additional degree of freedom is introduced to well-known single entry vanned or vaneless turbines. Moreover, the addition of the second inlet to the turbine volute brings extra complexity in determining the steady-state turbine performance parameters under unequal admission conditions. This thesis has a main novelty, which is a simple procedure for characterizing experimentally and elaborating characteristic maps of these turbines with unequal flow conditions. This method of analysis allows easy interpolating within the proposed distinctive maps or simple convincing models for calculating and extrapolating full performance parameters of twin-entry and dual-volute turbines. Here are also described two innovative 0D mean-line models that require a minimum quantity of experimental data for calibrating both: i.e. the mass flow parameter model and the isentropic efficiency model. Both models are predictive either in partial or unequal flow admission conditions using as inputs: the mass flow ratio and the total temperature ratio between the branches; the blade speed ratio and expansion ratio in each branch. These six inputs are generally instantaneously provided by 1D gas-dynamics codes.} Therefore, the novelty of the model is its ability to be used in a quasi-steady way for twin and dual-volute turbines performance prediction. This can be achieved instantaneously as turbines are calculated under pulsating and uneven flow conditions at turbocharged engines. Furthermore, a methodology for characterizing the discharge coefficient of a wastegate and scroll connection valve in a gas stand is shown. For estimating the gas flow over the same in one-dimensional models, an empirical model is correlated and validated. Finally, an optimal map of discharge coefficient has been drawn out through the interpolation method. This map can be integrated into the full one-dimensional turbocharged engine model system, in order to calculate the actual mass flow through the wastegate and scroll connection valves. Finally, the models have been fully validated by coupling them with one-dimensional modelling software and simulated both the gas stand and the whole engine measured points. On the one hand, the validation results from the gas stand simulation show that the model can predict well all steady flow variables. On the other hand, the validation results from the whole engine simulation show that the model is able to produce all the full load engine variables like air mass flow and brake torque in a reasonable degree of agreement with the experimental data.[CA] Malgrat la importància de les turbines radials amb doble entrada i de doble voluta per als motors turboalimentats, els seus mapes característics i el seu model completament predictiu mitjançant codis dinàmics de gas 1D encara no estan ben establerts. La complexitat del flux constant i l'admissió desigual d'aquestes turbines, quan funcionen amb polsos de gas d'escapament del motor, les converteixen en un sistema difícil. Principalment a causa de la admissió de flux desigual, s'introdueix un grau addicional de llibertat a les conegudes turbines vendes o d'entrada d'una sola entrada. A més, l'addició de la segona entrada a la voluta de la turbina aporta una complexitat addicional per determinar els paràmetres de rendiment de la turbina en estat estacionari en condicions d'admissió desigual. Aquesta tesi té com a novetat principal un procediment senzill per caracteritzar experimentalment i elaborar mapes característics d'aquestes turbines amb condicions de cabal desigual. Aquest mètode d'anàlisi permet interpolar fàcilment dins dels mapes distintius proposats o models senzills convincents per calcular i extrapolar paràmetres de rendiment complet de les turbines d'entrada doble i de doble voluta. Aquí també hem descrit dos models innovadors de línia mitjana 0D que requereixen una quantitat mínima de dades experimentals per calibrar tots dos: és a dir, el model de paràmetre de flux massiu i el model d'eficiència isentròpica. Els dos models són predictius en condicions d'admissió de flux parcial o desigual utilitzant com a entrada: la proporció de flux entre les branques; la relació total de la temperatura entre les branques; la relació velocitat fulla-raig a cada branca i la proporció de pressió a cada branca. Aquests cinc inputs generalment es proporcionen de manera instantània mitjançant codis de dinàmica de gas 1D. Per tant, la novetat del model és la seva capacitat d'utilitzar-se d'una manera quasi constant per a la predicció del rendiment de les turbines bessones i de doble voluta. Es pot aconseguir de forma instantània, ja que les turbines es calculen en condicions de flux pulsatòries i desiguals en motors turboalimentats. A més, es mostra una metodologia per a caracteritzar el coeficient de descàrrega d'una vàlvula de connexió per canals i desplaçaments en un suport de gas. Per estimar el flux de gas sobre el mateix en models unidimensionals, es correlaciona i valida un model empíric. Finalment, s'ha elaborat un mapa òptim de coeficient de descàrrega mitjançant el mètode d'interpolació, que pot integrar-se al sistema de model turboalimentat complet del motor turbo, per calcular el cabal de massa real a través de les vàlvules de connexió de desguàs i desplaçament. Finalment, els models s'han validat completament combinant-los amb un programari de modelatge unidimensional que simula tant el suport de gas com el motor sencer. D'una banda, els resultats de les validacions de l'estand de gas demostren que el model és capaç de predir bé totes les variables de flux constant. D'altra banda, els resultats de validació del motor complet demostren que el model és capaç de produir totes les variables del motor de càrrega completa, com ara el flux de massa d'aire i el pare de fre d'una bona manera amb les dades experimentals.Samala, V. (2020). Experimental characterization and mean line modelling of twin-entry and dual-volute turbines working under different admission conditions with steady flow [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/153475TESI

Liver Stiffness Measurements in Patients with Non‐cirrhotic Portal Hypertension – The Devil is In the Details

Non‐cirrhotic portal hypertension (NCPH) is often a diagnostic challenge due to signs and symptoms of portal hypertension that overlap with cirrhosis. The etiology of NCPH is broadly classified as prehepatic, hepatic (pre‐sinusoidal and sinusoidal) and post‐hepatic.1 Some common etiologies of NCPH encountered in clinical practice include portal vein thrombosis (prehepatic) and nodular regenerative hyperplasia (NRH) (hepatic)

Design of reverse converters for the multi-moduli residue number systems with moduli of forms 2a, 2b - 1, 2c + 1

Residue number system (RNS) is a non-weighted integer number representation system that is capable of supporting parallel, carry-free and high speed arithmetic. This system is error-resilient and facilitates error detection, error correction and fault tolerance in digital systems. It finds applications in Digital Signal Processing (DSP) intensive computations like digital filtering, convolution, correlation, Discrete Fourier Transform, Fast Fourier Transform, etc. The basis for an RNS system is a moduli set consisting of relatively prime integers. Proper selection of this moduli set plays a significant role in RNS design because the speed of internal RNS arithmetic circuits as well as the speed and complexity of the residue to binary converter (R/B or Reverse Converter) have a large dependency on the form and number of the selected moduli. Moduli of forms 2a, 2b- 1, 2c + 1 (a, b and c are natural numbers) have the most use in RNS moduli sets as these moduli can be efficiently implemented using usual binary hardware that lead to simple design. Another important consideration for the reverse converter design is the selection of an appropriate conversion algorithm from Chinese Remainder Theorem (CRT), Mixed Radix Conversion (MRC) and the new Chinese Remainder Theorems (New CRT I and New CRT II). This research is focused on designing reverse converters for the multi-moduli RNS sets especially four and five moduli sets with moduli of forms 2a, 2b- 1, 2c + 1 . The residue to binary converters are designed by applying the above conversion algorithms in different possible ways and facilitating the use of modulo (2k) and modulo (2k – 1) adders that lead to simple design of adder based architectures and VLSI efficient implementations (k is a natural number). The area and delay of the proposed converters is analyzed and an efficient reverse converter is suggested from each of the various four and five moduli set converters for a given dynamic range

Cloud-radiative impacts on the tropical Indian Ocean associated with the evolution of 'monsoon breaks'

A detailed diagnostic analysis of a suite of observed datasets was carried out with a view to understand the importance of cloud-radiative effects on the evolution of prolonged 'monsoon breaks' over the Indian region. The study particularly focuses on the role of clouds in affecting the sub-seasonal/intra-seasonal variability of sea surface temperature (SST) and atmospheric convection in the equatorial and south-eastern tropical Indian Ocean (SETIO) during monsoon-break transitions. A characteristic feature of the monsoon-break evolution is the appearance of suppressed convection over the SETIO region nearly 7-10 days prior to the commencement of a break spell over India. It is seen from the present analysis that the lack of cloud cover over the SETIO during the 'pre-break' phase leads to significant warming of the tropical Indian Ocean due to strong solar insolation at the surface. During the 'pre-break' phase, the net cloud-radiative forcing (NETCRF) at the surface is found to be typically around -30 Wm-2 and the mean SST in the SETIO is about 29.3°C. Following the transition to a monsoon-break phase, the cloud amount increases by about 25 over the SETIO region in association with intensified convection. The NETCRF at the surface over the SETIO averaged during the 'break' phase is found to be about -60 Wm-2 (i.e. a change of about -30 Wm-2 from the 'pre-break' phase). Consistent with the above change in the NETCRF, the SST in the SETIO shows a cooling of about 0.7°C, although the mean SSTs during the 'break' phase remain as high as 28.6°C. On the basis of the findings from this study, it is suggested that the SST warming during the 'pre-break' phase plays a key role in maintaining high SST and allows sustained convection to occur over the SETTO during prolonged monsoon breaks

Spiral Progression Approach in Teaching Science: A Case Study

The K to 12 curriculum implementation has institutionalized a curricular framework anchored on spiral progression, and this calls for new perspectives in the implementation of the teaching and learning process. This research study aimed to describe: the students’ perceptions on the vertical articulation of spiral progression approach (SPA); teachers’ perceptions in terms of vertical/horizontal articulation on learningcompetencies, mastery of subject matter, teaching strategies, and availability of instructional materials; positive experiences and problems encountered upon the implementation of SPA; and possible solutions for the identified problems. This study used the Modified Model of Comprehensive Assessment of an EducationalProgram in order to assess the students and teachers’ perceptions in SPA. Three research instruments were used in this study namely: structured interview, focus group discussion (FGD) and, interview/FGD questionnaires to support the respondents’ responses. The data gathered were assessed through open and axial coding system that led to the gathering of themes for easier evaluation. The findings revealed that vertical articulation of spiral progression provides deep understanding of science concepts through a thorough review conducted by the teachers. Furthermore, vertical and horizontal articulations in spiral progression are achieved through cooperative learning in consideration of the students’ propensity to easily forget what they have learned from the previous grade levels. Moreover, the use of instructional materials that fit the interests of the students and the mastery of the subject matter of the teachers helped in the retention of science concepts. Keywords: formative assessment, horizontal articulation, spiral progression approach, teaching science, vertical articulatio