Finite area method for nonlinear supersonic conical flows

A fully conservative numerical method for the computation of steady inviscid supersonic flow about general conical bodies at incidence is described. The procedure utilizes the potential approximation and implements a body conforming mesh generator. The conical potential is assumed to have its best linear variation inside each mesh cell; a secondary interlocking cell system is used to establish the flux balance required to conserve mass. In the supersonic regions the scheme is symmetrized by adding artificial viscosity in conservation form. The algorithm is nearly an order of a magnitude faster than present Euler methods and predicts known results accurately and qualitative features such as nodal point lift off correctly. Results are compared with those of other investigators

Continuity and Change in Saudi Arabia’s Development and Humanitarian Aid

This paper delves into the motivations and drivers behind Saudi Arabia’s foreign aid, shedding light on the interplay between geopolitics, religious affinity, and strategic objectives. Drawing on newly released empirical data from the Saudi Aid Platform (SAP) dataset, encompassing 47 years of aid delivery, the study seeks to answer the long-standing debate surrounding the factors shaping Saudi Arabia’s foreign aid decisions. The study focuses on two pivotal periods: the Bosnian War and the post-Arab Spring era. By examining Saudi aid allocations during these periods, we investigate the influence of foreign policy and geostrategic objectives versus the humanitarian needs of the recipients. Religious ideology, geopolitical interests, and strategic objectives drive Saudi Arabian aid. The study reveals that Saudi Arabia adopts a value-neutral strategic approach. The research contextualises these findings within geopolitical events, regional dynamics, and internal governance changes, providing insights into the factors influencing Saudi Arabia’s aid allocation decisions. By examining Saudi Arabian aid’s historical patterns and drivers, this study contributes to a deeper understanding of one of the world’s largest foreign aid providers. Additionally, it offers valuable insights for shaping effective aid strategies and policies in the future

Conditional value-at-risk for water management in Lake Burley Griffin

Copyright © Australian Mathematical SocietyAs the centrepiece of Canberra, Lake Burley Griffin provides the setting for buildings of national importance and a venue for aquatic recreation while, as part of the Molonglo River, the lake has a role in the ecological processes of its broader setting. For the purposes of recreation and landscape a constant water level is preferred: the management plan requires the lake to be maintained at a prescribed normal level. In years of low rainfall this requirement could conflict with the water demands of other users. Episodes of high rainfall may also require compromise between competing objectives. For example, drawdown of lake levels for flood mitigation could impact on the lake's recreational and amenity values and the spill may not be a good use of water. Conditional Value at Risk, a risk measure developed by the financial industry for portfolio management, is defined as the expected loss given that some loss threshold is exceeded. Here, Conditional Value at Risk is applied as decision support for strategic planning and day-to-day operational problems in the hydraulic management of Lake Burley Griffin.R. B. Webby, J. Boland, P. G. Howlett, A. V. Metcalfe, T. Srithara

Atmospheric Propagation of High Energy Lasers: Thermal Blooming Simulation

High Energy Laser (HEL) propagation through turbulent atmosphere is examined via numerical simulation. The beam propagation is modeled with the paraxial equation, which in turn is written as a system of equations for a quantum fluid, via the Madelung transform. A finite volume solver is applied to the quantum fluid equations, which supports sharp gradients in beam intensity. The atmosphere is modeled via a coupled advection-diffusion equation whose initial data have Kolmogorov spectrum. In this model the combined effects of thermal blooming, beam slewing, and deep turbulence are simulated

Coexistence of Ferroelectric Triclinic Phases and Origin of Large Piezoelectric Responses in Highly Strained BiFeO3 films

The structural evolution of the strain-driven morphotropic phase boundary (MPB) in BiFeO3 films has been investigated using synchrotron x-ray diffractometry in conjunction with scanning probe microscopy. Our results demonstrate the existence of mixed-phase regions that are mainly made up of two heavily tilted ferroelectric triclinic phases. Analysis of first-principles computations suggests that these two triclinic phases originate from a phase separation of a single monoclinic state accompanied by elastic matching between the phase-separated states. These first-principle calculations further reveal that the intrinsic piezoelectric response of these two low-symmetry triclinic phases is not significantly large, which thus implies that the ease of phase transition between these two energetically close triclinic phases is likely responsible for the large piezoelectric response found in the BiFeO3 films near its MPB. These findings not only enrich the understandings of the lattice and domain structure of epitaxial BiFeO3 films but may also shed some light on the origin of enhanced piezoelectric response near MPB.Comment: 19 pages, 3 figures and 1 tabl

Effect of different herbicide spray volumes on weed control efficiency of a battery-operated Unmanned aerial vehicle sprayer in transplanted rice (Oryza sativa L.)

The effect of spray volume on weed control in transplanted rice ecosystems using the Unmanned aerial vehicle (UAV) needs to be better understood for management in the advancements of UAV-based spraying technology. The present study aimed to find out the influence of varied spray volumes of 15 L/ha, 20 L/ha and 25 L/ha using the UAV and 500 L/ha using a Knapsack sprayer (KS) to compare the weed density, weed dry matter and weed control efficiency and yield in transplanted rice (Oryza sativa L.). Pre-emergence (PE) application of Pyrazosulfuron-ethyl at 25 g a.i./ha at three days after transplanting (DAT) and post-emergence (PoE) application of Bis-pyribac sodium at 25 g a.i./ha at 25 DAT were used as herbicide treatments. The results revealed that varied spray volumes significantly influenced the weed density, dry matter, and weed control efficiency of the UAV and KS. Application of herbicides using KS (500 L/ha) and UAV (25 L/ha) had better control on the weeds by reducing weed density and dry matter at 20, 40, and 60 DAT, with no significant difference. Higher grain yield and straw yield were recorded in KS (500 L/ha) and UAV (25 L/ha), with no significant difference. However, applying 25 L/ha had better weed control efficiency and higher yield, possibly due to optimum deposition. Considering the low volume application of UAV (25 L/ha) as compared with KS (500 L/ha), it is better to go for the optimal application of 25 L/ha, which is an energy-efficient and cost-effective, labour-saving approach compared to KS

MRI-guided adaptive radiotherapy for prostate cancer: When do we need to account for intra-fraction motion?

A shift of the daily plan can mitigate target position changes that occur between daily MR acquisition and treatment for MR-linac radiotherapy, but increases the session time. We demonstrated that our workflow strategy and decision-making process, to determine whether a subsequent shift is necessary, is appropriate

Remote sensing and GIS

Presented at the fifth international conference on irrigation and drainage, Irrigation and drainage for food, energy and the environment on November 3-6, 2009 in Salt Lake City, Utah.Includes bibliographical references.Managing water resources in western US has been a challenge for decision makers. In the last few decades, the rapid growth rates of population along with the alarming rates of global warming have added to the complexity of this issue. In this study, remote sensing techniques have been applied to evaluate the performance of agricultural irrigation, the largest consumptive user of water. The study area, "Palo Verde irrigation District" which is located in Riverside and Imperial counties, California, is an old irrigation district with a fairly heterogeneous cropping pattern. Landsat Thematic Mapper satellite images were used to estimate the actual ET using the SEBAL energy balance model. These estimates were integrated to obtain crop water demand for different periods throughout the growing season. The amount of diverted water was also estimated for the same periods, using flow measurements within the Palo Verde irrigation district. The results were analyzed within the ArcGIS environment in conjunction with water conveyance and field boundary layers to evaluate different performance indicators such as relative water supply, overall consumed ratio, depleted fraction, crop water deficit, and relative evapotranspiration. The results of these indicators can help irrigation managers to get a general idea of how the system performs and to identify possible ways of improving it

Learning anatomy - a pain in the neck?

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