The Computational Philosophy: Simulation as a Core Philosophical Method

Modeling and computer simulations, we claim, should be considered core philosophical methods. More precisely, we will defend two theses. First, philosophers should use simulations for many of the same reasons we currently use thought experiments. In fact, simulations are superior to thought experiments in achieving some philosophical goals. Second, devising and coding computational models instill good philosophical habits of mind. Throughout the paper, we respond to the often implicit objection that computer modeling is "not philosophical.

Single-Phase Operation of Three-Phase Motors

Against the current backdrop of deteriorating economic and financial conditions, the authors consider recent trends and current prospects for credit unions in Great Britain. Although credit unions have experienced solid membership and asset growth, there are clouds on the horizon. Bad debts and loan arrears are on the rise and may be linked to recent legislative amendments and the increasing use by government of credit unions as a mechanism to achieve its financial inclusion goals. Whatever the reason, the deterioration in the loan book needs to be quickly addressed, or it will ultimately result in either more government bailouts or a stream of failing credit unions

Analysis of Fin-Line at Millimeter Wavelengths

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryJoint Services Electronics Program / N00014-79-C-042

Current-density functional for disordered systems

The effective action for the current and density is shown to satisfy an evolution equation, the functional generalization of Callan-Symanzik equation. The solution describes the dependence of the one-particle irreducible vertex functions on the strength of the quenched disorder and the annealed Coulomb interaction. The result is non-perturbative, no small parameter is assumed. The a.c. conductivity is obtained by the numerical solution of the evolution equation on finite lattices in the absence of the Coulomb interaction. The static limit is performed and the conductivity is found to be vanishing beyond a certain threshold of the impurity strength.Comment: final version, 28 pages, 17 figures, to appear in Phys. Rev.

Photovoltaic characterisation of GaAsBi/GaAs multiple quantum well devices

A series of strained GaAsBi/GaAs multiple quantum well diodes are characterised to assess the potential of GaAsBi for photovoltaic applications. The devices are compared with strained and strain-balanced InGaAs based devices. The dark currents of the GaAsBi based devices are around 20 times higher than those of the InGaAs based devices. The GaAsBi devices that have undergone significant strain relaxation have dark currents that are a further 10–20 times higher. Quantum efficiency measurements show the GaAsBi devices have a lower energy absorption edge and stronger absorption than the strained InGaAs devices. These measurements also indicate incomplete carrier extraction from the GaAsBi based devices at short circuit, despite the devices having a relatively low background doping. This is attributed to hole trapping within the quantum wells, due to the large valence band offset of GaAsBi

Juvenile root traits show limited correlation with grain yield, yield components and grain mineral composition traits in Indian wheat under hostile soils

Correlations between juvenile wheat root traits, and grain yield and yield component traits under optimal field conditions have previously been reported in some conditions. The aim of this study was to test the hypothesis that juvenile wheat root traits correlate with yield, yield components and grain mineral composition traits under a range of soil environments in India. A diverse panel of 36 Indian wheat genotypes were grown for ten days in ‘pouch and wick’ high-throughput phenotyping (HTP) system (20 replicates). Correlations between juvenile root architecture traits, including primary and lateral root length, and grain yield, yield components and grain mineral composition traits were determined, using field data from previously published experiments at six sites in India. Only a limited number of juvenile root traits correlated with grain yield (GYD), yield components, and grain mineral composition traits. A narrow root angle, potentially representing a ‘steep’ phenotype, was associated with increased GYD and harvest index (HI) averaged across sites and years. Length related root traits were not correlated with GYD or HI at most sites, however, the total length of lateral roots and lateral root number correlated with GYD at a sodic site of pH 9.5. The total length of lateral roots (TLLR) correlated with grain zinc (Zn) concentration at one site. A wider root angle, representing a shallow root system, correlated with grain iron (Fe) concentration at most sites. The total length of all roots (TLAR) and total length of primary roots (TLPR) correlated with grain S concentration at most sites. Narrow root angle in juvenile plants could be a useful proxy trait for screening germplasm for improved grain yield. Lateral root and shallow root traits could potentially be used to improve grain mineral concentrations. The use of juvenile root traits should be explored further in wheat breeding for diverse environments

Simulation of bulk phases formed by polyphilic liquid crystal dendrimers

A coarse-grained simulation model for a third generation liquid crystalline dendrimer (LCDr) is presented. It allows, for the rst time, for a successful molecular simulation study of a relation between the shape of a polyphilic macromolecular mesogen and the symmetry of a macroscopic phase. The model dendrimer consists of a soft central sphere and 32 grafted chains each terminated by a mesogen group. The mesogenic pair interactions are modelled by the recently proposed soft core spherocylinder model of Lintuvuori and Wilson [J. Chem. Phys, 128, 044906, (2008)]. Coarse-grained (CG) molecular dynamics (MD) simulations are performed on a melt of 100 molecules in the anisotropic-isobaric ensemble. The model LCDr shows conformational bistability, with both rod-like and disc-like conformations stable at lower temperatures. Each conformation can be induced by an external aligning eld of appropriate symmetry that acts on the mesogens (uniaxial for rod-like and planar for disc-like), leading to formation of a monodomain smectic A (SmA) or a columnar (Col) phase, respectively. Both phases are stable for approximately the same temperature range and both exhibit a sharp transition to an isotropic cubic-like phase upon heating. We observe a very strong coupling between the conformation of the LCDr and the symmetry of a bulk phase, as suggested previously by theory. The study reveals rich potential in terms of the application of this form of CG modelling to the study of molecular self-assembly of liquid crystalline macromolecules.Розроблено огрублену модель рідкокристалічного дендримера (РКД) 3-ї генерації, завдяки чому вперше в літературі вивчено взаємозв'язок між формою рідкокристалічної макромолекули та симетрією макроскопічної фази за допомогою молекулярної динаміки. Модель складається з м'якої центральної сфери, до якої приєднано 32 ланцюжки, кожен із яких закінчується мезогенною групою. Останні взаємодіють за допомогою недавно запропонованого анізотропного потенціалу з м'якою серцевиною Лінтувуорі та Вілсона [J. Chem. Phys, 128, 044906, (2008)]. За допомогою методу огрубленої молекулярної динаміки змодельовано розплав 100 молекул РКД в анізотропно-ізобаричному ансамблі. Запропонована модель РКД продемонструвала конформаційну бістабільність, за якої як паличкоподібна, так і дископодібна конформації виявляються стабільними за низьких температур. Кожна з цих 2-х конформацій може ініціюватись зовнішнім полем із відповідною симетрією, в результаті в розплаві спонтанно формуються або монодоменна смектична фаза (із паличкоподібних конформацій, ініційованих одновісним полем), або стовпцева фаза (із дископодібних конформацій, ініційованих планарним полем). Обидві фази є стабільними приблизно в тому ж температурному інтервалі та у процесі нагрівання переходять в ізотропну кубічну фазу через яскраво виражений фазовий перехід. Спостережено сильний зв'язок між конформацією РКД і симетрією об'ємної фази, на що вказано раніше в теоретичних роботах. Дослідження виявляє великий потенціал в застосуванні огрубленого моделювання до опису просторової самоорганізації рідкокристалічних макромолекул

Eruption of ammonia-water cryomagmas on Titan 1: crystallisation and cooling during ascent

We are developing a semi-analytical model for the ascent of methane-expansion driven ammonia-water cryomagmas on Titan. The range of different crystal fractions resulting from decompression may help to explain the range of apparent rheological properties inferred for surface features

Critical Exponents for Nuclear Multifragmentation: dynamical lattice model

We present a dynamical and dissipative lattice model, designed to mimic nuclear multifragmentation. Monte-Carlo simulations with this model show clear signature of critical behaviour and reproduce experimentally observed correlations. In particular, using techniques devised for finite systems, we could obtain two of its critical exponents, whose values are in agreement with those of the universality class to which nuclear multifragmentation is supposed to belong.Comment: 10 pages, 3 figures, to be published in Nuclear Physics