Mathematical modelling and numerical simulation of phosphine flow during grain fumigation in leaky cylindrical silos

The phosphine distribution in a cylindrical silo containing grain is predicted. A three-dimensional mathematical model, which accounts for multicomponent gas phase transport and the sorption of phosphine into the grain kernel is developed. In addition, a simple model is presented to describe the death of insects within the grain as a function of their exposure to phosphine gas. The proposed model is solved using the commercially available computational fluid dynamics (CFD) software, FLUENT, together with our own C code to customize the solver in order to incorporate the models for sorption and insect extinction. Two types of fumigation delivery are studied, namely, fan- forced from the base of the silo and tablet from the top of the silo. An analysis of the predicted phosphine distribution shows that during fan forced fumigation, the position of the leaky area is very important to the development of the gas flow field and the phosphine distribution in the silo. If the leak is in the lower section of the silo, insects that exist near the top of the silo may not be eradicated. However, the position of a leak does not affect phosphine distribution during tablet fumigation. For such fumigation in a typical silo configuration, phosphine concentrations remain low near the base of the silo. Furthermore, we find that half-life pressure test readings are not an indicator of phosphine distribution during tablet fumigation.

Introduction

This paper conceptualises think tanks and edu-businesses in relation to education policy work in the Australian polity. It situates the enhanced influence of both in relation to the restructured state, which has lost some key capacities in relation to the generation of research and ideas for policy. This restructuring has been strongly influenced by the techniques of new public management, the auditing of education through national and international testing and new forms of network governance, which have opened up spaces for the increased influence of think tanks and edu-businesses across the policy cycle in education. We see here the workings of a ‘polycentric state’. The paper also considers changing concepts of ‘evidence’, ‘expertise’ and ‘influence’ in respect of the involvement of think tanks and edu-businesses in circulating policy ideas and affecting policy development in Australian education. This introduction to this special issue of The Australian Educational Researcher serves as a provocation to further research on this new policy scenario.

Ethyl 4-(4-hydroxyphenyl)-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carbox ylate monohydrate

In the title compound, C14H16N2O4 center dot H2O, the dihedral angles between the planes of the 4-hydroxyphenyl and ester groups with the plane of the six-membered tetrahydropyrimidine ring are 87.3 (1) and 75.9 (1)degrees, respectively. The crystal structure is stabilized by O-H center dot center dot center dot O and N-H center dot center dot center dot O hydrogen bonding between the water molecule and the organic functionalities.

Ethyl 4-(4-chlorophenyl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate

In the title compound, C14H15ClN2O2S, the tetrahydropyrimidine ring adopts a twisted boat conformation with the carbonyl group in an s-trans conformation with respect to the C C double bond of the six-membered tetrahydropyrimidine ring. The molecular conformation is determined by an intramolecular C-H center dot center dot center dot pi interaction. The crystal structure is further stabilized by intermolecular N-H center dot center dot center dot O molecular chains and centrosymmetric N-H center dot center dot center dot S dimers.

Pastoral care in times of high stakes testing and accountability

The unknown future is a challenge to educators in preparing young people for life post school. While history can be said to repeat itself, the reality is that each generation is faced with new challenges and threats. Therefore, the challenge for contemporary schooling is to prepare students to live in a fast paced, complex world where threats such as terrorism, cyberbullying and depleted resources are juggled with high stakes testing and curriculum accountability. This presentation draws on the notion of a future of supercomplexity while critically examining current pastoral care delivery in schools to develop a new model of practice in preparing students for an unknown future.

Analysis of cool roof coatings for residential demand side management in tropical Australia

Cool roof coatings have a beneficial impact on reducing the heat load of a range of building types, resulting in reduced cooling energy loads. This study seeks to understand the extent to which cool roof coatings could be used as a residential demand side management (DSM) strategy for retrofitting existing housing in a constrained network area in tropical Australia where peak electrical demand is heavily influenced by residential cooling loads. In particular this study seeks to determine whether simulation software used for building regulation purposes can provide networks with the ‘impact certainty’ required by their DSM principles. The building simulation method is supported by a field experiment. Both numerical and experimental data confirm reductions in total consumption (kWh) and energy demand (kW). The nature of the regulated simulation software, combined with the diverse nature of residential buildings and their patterns of occupancy, however, mean that simulated results cannot be extrapolated to quantify benefits to a broader distribution network. The study suggests that building data gained from regulatory simulations could be a useful guide for potential impacts of widespread application of cool roof coatings in this region. The practical realization of these positive impacts, however, would require changes to the current business model for the evaluation of DSM strategies. The study provides seven key recommendations that encourage distribution networks to think beyond their infrastructure boundaries, recognising that the broader energy system also includes buildings, appliances and people.

Ethyl 6-methyl-2-sulfanylidene-4-[4(trifluoromethyl)phenyl]-1,2,3,4-tetrahyd ropyrimidine-5-carboxylate

The title compound, C(15)H(15)F(3)N(2)O(2)S, adopts a conformation with an intramolecular C-H center dot center dot center dot pi interaction. The dihedral angles between the planes of the 4-(trifluoromethyl) phenyl and ester groups with the plane of the six-membered tetrahydropyrimidine ring are 81.8 (1) and 16.0 (1)degrees, respectively. In the crystal structure, intermolecular N-H center dot center dot center dot S hydrogen bonds link pairs of molecules into dimers and N-H center dot center dot center dot O interactions generate hydrogen-bonded molecular chains along the crystallographic a axis.

Advances in base- and mobile-station aided cooperative wireless communications : An overview

In recent years, there has been an upsurge of research interest in cooperative wireless communications in both academia and industry. This article presents a simple overview of the pivotal topics in both mobile station (MS)- and base station (BS)- assisted cooperation in the context of cellular radio systems. Owing to the ever-increasing amount of literature in this particular field, this article is by no means exhaustive, but is intended to serve as a roadmap by assembling a representative sample of recent results and to stimulate further research. The emphasis is initially on relay-base cooperation, relying on network coding, followed by the design of cross-layer cooperative protocols conceived for MS cooperation and the concept of coalition network element (CNE)-assisted BS cooperation. Then, a range of complexity and backhaul traffic reduction techniques that have been proposed for BS cooperation are reviewed. A more detailed discussion is provided in the context of MS cooperation concerning the pros and cons of dispensing with high-complexity, power-hungry channel estimation. Finally, generalized design guidelines, conceived for cooperative wireless communications, are presented.

Sapientia, 1997, Vol. LII, nº 201 (número completo)

Contenido: El aristotelismo y el tomismo frente al egoísmo psicológico / María L. Lukac de Stier – El deseo natural de ver a Dios en la Summa contra Gentiles / Guillermo Jorge Cambiasso – La creación como encuentro del ser y de la nada en la teología del maestro Eckhart de Hochheim O.P. (1260-1327) / Brian J. Farrelly – Malebranche y el libertinage érudit / Francisco Leocata – The problem of person and Jean Mouroux / John M. McDermott ; Glenn J. Comandini – Los fundamentos de la Bioética de H. Tristram Engelhardt / Jorge Martínez Barrera – Cuando las contradictorias son verdaderas / Marisa Villalba de Tablón – Examen del escepticismo moral y del relativismo moral / Camilo Tale – Saint Thomas et le mystère de la création : une réponse aux interrogations de l’homme d’aujourd’hui / Marie-Dominique Philippe – La finalidad de la naturaleza humana : alcance y actualidad de la cuestión / Beatriz Eugenia Reyes Oribe – La providencia y el gobierno del mundo / Alberto Caturelli – Saint Thomas et le problème de la possibilité d’un univers créé éternel / Alain-Marie de Lassus – La causalidad material de los elementos en la generación de los cuerpos mixtos / Mario Enrique Sacchi -- Bibliografía

Evaluación del efecto de la fertilización mineral y orgánica (gallinaza) en el crecimiento y rendimiento del cultivo del maiz (Zea mays L.) variedad NB-S en la estación experimental "La Compañía" época de primera 2002

El presente estudio se realizó en la estación experimental “La Compañía ”, San Marcos, Carazo, durante la época de primera 2002. El estudio se llevó a cabo en dos áreas experimentales analizadas por separado; para los tratamientos minerales se hizo uso del fertilizante mineral completo (12-30-10) complementado con urea (46%) y un testigo; como fuente de abono orgánico se utilizó gallinaza, con aplicaciones de 20 y 10 t/ha y su respectivo testigo. Los tratamientos fueron arreglados en un experimento unifactorial con diseño de Bloques Completos al Azar (BCA) con tres tratamientos y cuatro repeticiones para cada área experimental, la variedad de maíz (Zea maysL.) evaluada fue NB-S. Las variables evaluadas fueron: altura de plantas (cm), altura del último nudo (cm), número de hojas, diámetro del tallo(cm), área foliar(cm2), diámetro de mazorca(cm), número de hileras por mazorca, número de granos por hilera, peso de 100 granos en gramos (g) y rendimiento en kg/ha. Los datos se procesaron usando Análisis de Varianza y con la prueba de rangos múltiples de Tukey al 95 % de confiabilidad. Se realizó un análisis económico utilizando la metodología planteada por el CIMMYT (1988) para evaluar la rentabilidad de los tratamientos. Los resultados obtenidos con la dosis de 150 kg N/ha se obtuvieron los mayores resultados para las variables área foliar, diámetro del tallo, número de hileras por mazorca, diámetro de mazorca y peso de 100 granos. La aplicación de 75 kg N/ha produjo superiores resultados para altura de planta, número de hojas, altura del último nudo, número de granos por hileras y rendimiento en kg/ha, así mismo resultó ser la más rentable, obteniéndose valores adicionales de 0.43 dólares por cada dólar invertido. En tanto para el ensayo orgánico la aplicación de 20 t/ha de gallinaza obtuvo mejores resultados para las variables altura de planta, área foliar, número de hojas; altura del último nudo y número de granos por hileras y los mayores rendimientos en kg/ha. Sin embargo la aplicación de 10 t/ha de gallinaza registró el mayor diámetro del tallo, número de hilera por mazorca, diámetro de mazorca y peso de 100 granos en gramos. La dosis de 10 t/ha de gallinaza resulto ser la más rentable reflejando una ganancia de 1.21 dólar por cada dólar invertido en el tratamiento.

Improving the chances for developing coastal country success in adapting to climate change

There is an unequivocal scientific consensus that increases in greenhouse gases in the atmosphere drive warming temperatures of air and sea, and acidification of the world’s oceans from carbon dioxide absorbed by the oceans. These changes in turn can induce shifts in precipitation patterns, sea level rise, and more frequent and severe extreme weather events (e.g. storms and sea surge). All of these impacts are already being witnessed in the world’s coastal regions and are projected to intensify in years to come. Taken together, these impacts are likely to result in significant alteration of natural habitats and coastal ecosystems, and increased coastal hazards in low-lying areas. They can affect fishers, coastal communities and resource users, recreation and tourism, and coastal infrastructure. Approaches to planned adaptation to these impacts can be drawn from the lessons and good practices from global experience in Integrated Coastal Management (ICM). The recently published USAID Guidebook on Adapting to Coastal Climate Change (USAID 2009) is directed at practitioners, development planners, and coastal management professionals in developing countries. It offers approaches for assessing vulnerability to climate change and climate variability in communities and outlines how to develop and implement adaptation measures at the local and national levels. Six best practices for coastal adaptation are featured in the USAID Guidebook on Adapting to Coastal Climate Change and summarized in the following sections. (PDF contains 3 pages)

Study of the origins of toughness in amorphous metals

Amorphous metals that form fully glassy parts over a few millimeters in thickness are still relatively new materials. Their glassy structure gives them particularly high strengths, high yield strains, high hardness values, high resilience, and low damping losses, but this can also result in an extremely low tolerance to the presence of flaws in the material. Since this glassy structure lacks the ordered crystal structure, it also lacks the crystalline defect (dislocations) that provides the micromechanism of toughening and flaw insensitivity in conventional metals. Without a sufficient and reliable toughness that results in a large tolerance of damage in the material, metallic glasses will struggle to be adopted commercially. Here, we identify the origin of toughness in metallic glass as the competition between the intrinsic toughening mechanism of shear banding ahead of a crack and crack propagation by the cavitation of the liquid inside the shear bands. We present a detailed study over the first three chapters mainly focusing on the process of shear banding; its crucial role in giving rise to one of the most damage-tolerant materials known, its extreme sensitivity to the configurational state of a glass with moderate toughness, and how the configurational state can be changed with the addition of minor elements. The last chapter is a novel investigation into the cavitation barrier in glass-forming liquids, the competing process to shear banding. The combination of our results represents an increased understanding of the major influences on the fracture toughness of metallic glasses and thus provides a path for the improvement and development of tougher metallic glasses.

Surface effects on spinwave resonance in thin magnetic films

Over the past few decades, ferromagnetic spinwave resonance in magnetic thin films has been used as a tool for studying the properties of magnetic materials. A full understanding of the boundary conditions at the surface of the magnetic material is extremely important. Such an understanding has been the general objective of this thesis. The approach has been to investigate various hypotheses of the surface condition and to compare the results of these models with experimental data. The conclusion is that the boundary conditions are largely due to thin surface regions with magnetic properties different from the bulk. In the calculations these regions were usually approximated by uniform surface layers; the spins were otherwise unconstrained except by the same mechanisms that exist in the bulk (i.e., no special "pinning" at the surface atomic layer is assumed). The variation of the ferromagnetic spinwave resonance spectra in YIG films with frequency, temperature, annealing, and orientation of applied field provided an excellent experimental basis for the study.

This thesis can be divided into two parts. The first part is ferromagnetic resonance theory; the second part is the comparison of calculated with experimental data in YIG films. Both are essential in understanding the conclusion that surface regions with properties different from the bulk are responsible for the resonance phenomena associated with boundary conditions.

The theoretical calculations have been made by finding the wave vectors characteristic of the magnetic fields inside the magnetic medium, and then combining the fields associated with these wave vectors in superposition to match the specified boundary conditions. In addition to magnetic boundary conditions required for the surface layer model, two phenomenological magnetic boundary conditions are discussed in detail. The wave vectors are easily found by combining the Landau-Lifshitz equations with Maxwell's equations. Mode positions are most easily predicted from the magnetic wave vectors obtained by neglecting damping, conductivity, and the displacement current. For an insulator where the driving field is nearly uniform throughout the sample, these approximations permit a simple yet accurate calculation of the mode intensities. For metal films this calculation may be inaccurate but the mode positions are still accurately described. The techniques necessary for calculating the power absorbed by the film under a specific excitation including the effects of conductivity, displacement current and damping are also presented.

In the second part of the thesis the properties of magnetic garnet materials are summarized and the properties believed associated with the two surface regions of a YIG film are presented. Finally, the experimental data and calculated data for the surface layer model and other proposed models are compared. The conclusion of this study is that the remarkable variety of spinwave spectra that arises from various preparation techniques and subsequent treatments can be explained by surface regions with magnetic properties different from the bulk.

Paranormal operator on a Hilbert space

In this thesis an extensive study is made of the set P of all paranormal operators in B(H), the set of all bounded endomorphisms on the complex Hilbert space H. T ϵ B(H) is paranormal if for each z contained in the resolvent set of T, d(z, σ(T))//(T-zI)^-1 = 1 where d(z, σ(T)) is the distance from z to σ(T), the spectrum of T. P contains the set N of normal operators and P contains the set of hyponormal operators. However, P is contained in L, the set of all T ϵ B(H) such that the convex hull of the spectrum of T is equal to the closure of the numerical range of T. Thus, N≤P≤L.

If the uniform operator (norm) topology is placed on B(H), then the relative topological properties of N, P, L can be discussed. In Section IV, it is shown that: 1) N P and L are arc-wise connected and closed, 2) N, P, and L are nowhere dense subsets of B(H) when dim H ≥ 2, 3) N = P when dimH ˂ ∞ , 4) N is a nowhere dense subset of P when dimH ˂ ∞ , 5) P is not a nowhere dense subset of L when dimH ˂ ∞ , and 6) it is not known if P is a nowhere dense subset of L when dimH ˂ ∞.

The spectral properties of paranormal operators are of current interest in the literature. Putnam [22, 23] has shown that certain points on the boundary of the spectrum of a paranormal operator are either normal eigenvalues or normal approximate eigenvalues. Stampfli [26] has shown that a hyponormal operator with countable spectrum is normal. However, in Theorem 3.3, it is shown that a paranormal operator T with countable spectrum can be written as the direct sum, N ⊕ A, of a normal operator N with σ(N) = σ(T) and of an operator A with σ(A) a subset of the derived set of σ(T). It is then shown that A need not be normal. If we restrict the countable spectrum of T ϵ P to lie on a C²-smooth rectifiable Jordan curve G_o, then T must be normal [see Theorem 3.5 and its Corollary]. If T is a scalar paranormal operator with countable spectrum, then in order to conclude that T is normal the condition of σ(T) ≤ G_o can be relaxed [see Theorem 3.6]. In Theorem 3.7 it is then shown that the above result is not true when T is not assumed to be scalar. It was then conjectured that if T ϵ P with σ(T) ≤ G_o, then T is normal. The proof of Theorem 3.5 relies heavily on the assumption that T has countable spectrum and cannot be generalized. However, the corollary to Theorem 3.9 states that if T ϵ P with σ(T) ≤ G_o, then T has a non-trivial lattice of invariant subspaces. After the completion of most of the work on this thesis, Stampfli [30, 31] published a proof that a paranormal operator T with σ(T) ≤ G_o is normal. His proof uses some rather deep results concerning numerical ranges whereas the proof of Theorem 3.5 uses relatively elementary methods.

Seasonal Occurrence of the White Shark, Carcharodon carcharias, in Waters off the Florida West Coast, with Notes on its Life History

The white shark, Carcharodon carcharias, is considered rare in the Gulf of Mexico; however, recent longline captures coupled with historical landings information suggest that the species occurs seasonally (winter-spring) within this region. We examined a total of seven adult and juvenile white sharks (185-472 em total length) captured in waters off the west coast of Florida. Commercial longline fisheries were monitored for white sharks during all months (1981-94), but this species was captured only from January to April. All white sharks were captured in continental shelf waters from 37 to 222 km off the west coast of Florida when sea surface temperatures ranged from 18.7° to 21.6°C. Depths at capture locations ranged from 20 to 164 m. Fishing gear typically used in Gulf of Mexico offshore fisheries may not be effective at capturing this species, and the apparent rarity of white sharks in this area may be, in part, a function of gear bias.