Groupwise evacuation with genetic algorithms

In a crisis situation on board a ship, it can be of the utmost importance to have the passengers safely evacuate to the lifeboats in an efficient manner. Existing methods such as marked escape routes, maps and so on are not optimal as pre-planned escape routes may become heavily congested by passengers. The closest lifeboat is not always feasible as lifeboat capacity can be exceeded. Considering that some evacuees are strongly affiliated and would like to evacuate together as a group, it all becomes a very difficult problem to solve. Sub-problems have been modelled, but no existing model combines all of these aspects into account. We proceed by modelling the area to be evacuated as a time-expanded graph, assuming that future development in hazard severity is known in the form of a survivability percentage for each node. Then we apply a multi-objective genetic algorithm with five different fitness functions that use heuristics to maximize overall survivability and reduce the total egress time if possible. A method has been developed to pick the best evacuation plan out of the pool of potential solutions returned by the genetic algorithm. The solution is compared with Dijkstra’s algorithm and randomly generated paths. Experiments are conducted using these algorithms for both predefined and randomly generated graphs using different parameters. In the tested random graph, the genetic algorithm gives on average 24% better survivability and 3 times better grouping Random algorithms. A fixed network with a known solution was solved 100%. This genetic algorithm can be used to generate better routing plans that utilizes multiple evacuation routes and lifeboats while taking into account groups, resulting in smoother evacuations which can save more lives

Compendio histórico de la vida de Santa Rosa de Lima, con un apéndice de la gloria póstuma de la misma santa

Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 201

The application of alternating-direction implicit methods to the space-dependent kinetics equations

Cover title"MIT-3903-3."Originally presented as the first author's thesis (Ph. D.), M.I.T. Dept. of Nuclear Engineering, 1969Includes bibliographical references (leaves 54-55)Prepared under U.S. Atomic Energy Commission AT(30-1) 390

Analyse eines Abweiseradsichters in Kombination mit einem triboelektrischen Materialsortierer

Durch den immer größer werdenden Bedarf an Rohstoffen in der Industrie und Gesellschaft ist es notwendig nicht nur neue Ressourcen zu erschließen und abzubauen, sondern auch bereits verbrauchte Güter wieder zu recyclen und damit in die Kreislaufwirtschaft einzubringen. Oftmals sind Recycling-Prozesse jedoch aufwendig und teuer, da die zu gewinnenden Materialien nur unter Einsatz von chemischen Zusätzen in der Nassphase (bspw. Flotation) zu gewinnen sind. Eine der größten Schwierigkeiten besteht darin, dass, sobald zwei Materialien dieselbe Dichte aufweisen und sich keine anderen Eigenschaften, wie bspw. Magnetismus oder Leitfähigkeit für die Trennung eignen, diese nicht mehr in der Trockenphase zu trennen sind. Die Nassphase ermöglicht das Ausnutzen weiterer Eigenschaften (z.B. Benetzbarkeit), sodass eine Trennung dennoch ermöglicht werden kann. Durch den bereits erwähnten Einsatz von chemischen Mitteln bedeutet dies zusätzlich eine teure Abwasserentsorgung/-aufbereitung und eine Trocknung der generierten Fraktionen, was wiederum mit einem höheren Energieaufwand verbunden ist. Es ist demnach erstrebenswert in der Trockenphase zu verbleiben, sofern die zu trennenden Materialien bereits in der Trockenphase vorliegen. Vor der Sortierung von Partikeln ist meist eine Vorkonditionierung notwendig. Bspw. müssen grobes Gestein oder Schlacken, dessen Partikel aus mehreren Bestandteilen bestehen erst zerkleinert werden, um die eingeschlossenen Bestandteile freizulegen. Bevor also die Sortierung (Trennung nach Stoffeigenschaften wie Dichte, Benetzbarkeit, etc.) stattfinden kann, muss eine ausreichende Zerkleinerung garantiert werden und die feinen Partikel von den Groben getrennt werden. Diese Sortierung nach Grob- und Feingut kann durch eine vorgeschaltete Klassierung (Trennung nach Feinheitsmerkmalen wie Partikelgröße) geschehen. In dieser Arbeit wurde ein solcher zweidimensionaler Trennprozess (1. Trennung nach Partikelgröße; 2. Trennung nach Material) in der Trockenphase realisiert. Für den ersten Schritt der Klassierung wurde ein Abweiseradsichter verwendet, da dieser für industriell relevante Mengen den Bereich der Feinstpartikel dominiert und bei hohen Beladungen Trenngrenzen im Bereich einiger Mikrometer und kleiner aufweist. Da für die Befreiung des Wertstoffes aus Gestein und Erzen eine kleine Partikelgröße erreicht werden muss, wurde eine dementsprechend kleine Trenngrenze des Sichters angestrebt. Im Rahmen dieser Arbeit wurde daher ein neuer Sichter mit einer Trenngrenze von unter 10 μm konstruiert, der Einfluss von verschiedenen modularen Bauteilen (vor allem Sichtrad und dessen Peripherie) und dessen Bedeutung für das Trennverhalten untersucht. Weiterhin wurde der Einfluss unterschiedlicher Aufgabegüter auf den Klassierprozess (Kalkstein und Spinell) betrachtet, aber auch die sogenannte triboelektrische Aufladung, welche durch die Stöße der Partikel mit Bauteilen des Abweiseradsichters entsteht. Im Normalfall ist die triboelektrische Aufladung unerwünscht, da diese durch spontane Entladung zu Staubexplosionen führen kann. Jedoch handelt es sich hierbei um einen materialspezifischen Auflademechanismus, der bei nahezu jedem Partikeltransport auftritt. Während der im Recyclingprozess ohnehin notwendigen Klassierung im Abweiseradsichter werden die Partikel ohne weiteren Energieeintrag oder Aufwand aufgeladen. Durch die Integration eines elektrischen Abscheiders bzw. Sortierers in die Feingutleitung, kann so die triboelektrische Aufladung für die Materialsortierung verwendet werden. Da die triboelektrische Aufladung noch weitgehend unerforscht ist, werden zusätzlich verschiedene Einflüsse auf diese und die anschließende Trennung untersucht. Das geschieht zunächst im Labormaßstab, um anschließend die so gewonnenen Erkenntnisse für den Einbau eines elektrostatischen Trenners in den Abweiseradsichter zu nutzen. Die frei verfügbare triboelektrische Aufladung wird somit als Sortiermerkmal ausgenutzt, ohne dabei den erwähnten Aufwand mit (chemischen) Vorbehandlungen und aufwendigen Aufbereitungsverfahren - wie in der Nassphase - hinnehmen zu müssen.Because of the constantly increasing need for raw materials in society and industry, it is necessary to not only develop and mine new resources but also recycle previously used products and feed them into the circular economy. However, because the components to be recovered may only be retrieved by utilizing chemical additives in the wet phase, recycling procedures are frequently complicated and expensive (e.g. flotation). One of the main challenges is that two materials cannot be separated in the dry phase once they share a comparable density and no other qualities, such as conductivity or magnetism, are accessible for separation. Other characteristics, including wettability, can be used in the wet phase to still allow a successful separation. Owing to the previously indicated usage of chemical agents, this also entails costly wastewater disposal/treatment and drying of the produced fractions, which is linked to increased energy consumption. So, if the materials to be separated are already present in the dry phase, it is preferable to stay there. In most cases, preconditioning is required before particles can be sorted. For instance, it is necessary to first crush coarse stones or slags whose particles are made up of numerous components to reveal the desired materials. Consequently, substantial size reduction is required before sorting (separation according to material characteristics such as density, wettability, etc.) can occur and a separation of the fine material from the coarse is neccessary. This sorting into coarse and fine material can be done by upstream classification (separation by fineness characteristics such as particle size). In this work, such a two-dimensional separation process (1. separation by particle size; 2. separation by material) was realized in the dry phase. For the first step of classification, a deflector wheel classifier was used, since it dominates the range of ultra-fine particles for industrially relevant quantities and has separation limits in the range of less than a few micrometers for high mass loadings. Since the liberation of the valuable material from rocks and ores requires the achievement of a small particle size, a correspondingly small cut size of the classifier was aimed for. In the context of this work, a new classifier with a separation limit of less than 10 μm was built. The relevance of the separation behavior and the influence of various modular components, particularly the classifier wheel and its periphery, were examined as well as the impact of various feed materials on the classification process such as limestone and spinel. Due to particle collisions with deflector wheel classifier components the so-called triboelectric charging occurs during the separation process, which was additionally investigated. Triboelectric charging is typically undesired since it might cause spontaneous discharges that result in dust explosions. However, it is a material-specific charging mechanism that occurs in almost every particle transport. Thus the particles are charged during the separation process in the deflector wheel classifier without any additional energy input or effort as the separation process is required for the recycling process anyway. By integrating an electrical precipitator or sorter into the fines tube, triboelectric charging can be used for material sorting. Since triboelectric charging is still largely unexplored, various influences on it and subsequent separation are also being investigated. This will first be done on a laboratory scale, and the knowledge gained will then be used for the installation of an electrostatic precipitator in the deflector wheel classifier. Hence, the freely available triboelectric charge is utilized as a sorting feature without facing the previously described costs of (chemical) pretreatment and complex preparation operations, as in the wet phase

Pulsar Kicks With Modified URCA and Electrons in Landau Levels

We derive the energy asymmetry given the proto-neutron star during the time when the neutrino sphere is near the surface of the proto-neutron star, using the modified URCA process. The electrons produced with the anti-neutrinos are in Landau levels due to the strong magnetic field, and this leads to asymmetry in the neutrino momentum, and a pulsar kick. The magnetic field must be strong enough for a large fraction of the eletrons to be in the lowest Landau level, however, there is no direct dependence of our pulsar velocity on the strength of the magnetic field. Our main prediction is that the large pulsar kicks start at about 10 s and last for about 10 s, with the corresponding neutrinos correlated in the direction of the magnetic field. We predict a pulsar velocity of 1.03 $\times 10^{-4} (T/10^{10}K)^7$ km/s, which reaches 1000 km/s if T $\simeq 9.96 \times 10^{10}$ K.Comment: 11 pages, 6 figure

Evaluation Framework for Water Quality Trading Programs in the Chesapeake Bay Watershed

Water quality trading programs are being proposed and implemented across the US in a variety of forms and with differing objectives. The programs being proposed and implemented in the Chesapeake Bay region are no exception. Against this background the Chesapeake Bay Program's Scientific and Technical Advisory Committee and the Mid-Atlantic Water Program requested a general framework to inform and guide the evaluation of the performance trading programs. This resulting report was developed by a workgroup comprised of ten individuals with extensive experience in the study, design, and evaluation of trading programs. While the impetus for this report was to improve evaluation of trading programs in the Chesapeake Bay region, the evaluation framework is broad enough to apply to trading programs in general

Forced triboelectrification of fine powders in particle wall collisions

Triboelectric separation as an inexpensive and environmentally friendly technique could contribute to material-specific sorting. However, the application as a widespread method is limited due to the complexity of the process. In particle wall collisions, various parameters like collision energy and angle, work function of the contact partners, humidity, surface roughness, etc. influence the particle charging in a hardly predictable way. This study investigates the possibilities of forced triboelectric particle charging by applying an electrical potential to the metal contact partner (copper/steel pipe). The variations included different pipe lengths (0.5 m–3 m), particle materials, and particle sizes for limestone. A distinction is made between the net charge of the particles and the positive, negative, and neutral mass fractions. The work functions of the investigated materials vary from about 3.2 eV to >8.5 eV for glass, limestone, artificial slag, and lithium aluminate particles. With the applied high-voltage potential, the particle net charge can be shifted linearly. For limestone, it is shown that the neutral fraction is highest at the Point of Zero Net Charge (PZNC). This observation may identify an approach for the material selective separation of one target component from a multi-material mixture

Hypervelocity Collisions of Binary Stars at the Galactic Centre

Recent surveys have identified seven hypervelocity stars (HVSs) in the halo of the Milky Way. Most of these stars may have originated from the breakup of binary star systems by the nuclear black hole SgrA*. In some instances, the breakup of the binary may lead to a collision between its member stars. We examine the dynamical properties of these collisions by simulating thousands of different binary orbits around SgrA* with a direct N-body integration code. For some orbital parameters, the two stars collide with an impact velocity lower than their escape velocity and may therefore coalesce. It is possible for a coalescing binary to have sufficient velocity to escape the galaxy. Furthermore, some of the massive S-stars near Sgr A* might be the merger remnants of binary systems, however this production method can not account for most of the S-stars.Comment: 5 pages, 2 figures, accepted for publication in MNRA

New Constraints on the Complex Mass Substructure in Abell 1689 from Gravitational Flexion

In a recent publication, the flexion aperture mass statistic was found to provide a robust and effective method by which substructure in galaxy clusters might be mapped. Moreover, we suggested that the masses and mass profile of structures might be constrained using this method. In this paper, we apply the flexion aperture mass technique to HST ACS images of Abell 1689. We demonstrate that the flexion aperture mass statistic is sensitive to small-scale structures in the central region of the cluster. While the central potential is not constrained by our method, due largely to missing data in the central 0.5$^\prime$ of the cluster, we are able to place constraints on the masses and mass profiles of prominent substructures. We identify 4 separate mass peaks, and use the peak aperture mass signal and zero signal radius in each case to constrain the masses and mass profiles of these substructures. The three most massive peaks exhibit complex small-scale structure, and the masses indicated by the flexion aperture mass statistic suggest that these three peaks represent the dominant substructure component of the cluster ($\sim 7\times 10^{14}h^{-1}M_\odot$). Their complex structure indicates that the cluster -- far from being relaxed -- may have recently undergone a merger. The smaller, subsidiary peak is located coincident with a group of galaxies within the cluster, with mass $\sim 1\times10^{14}h^{-1}M_\odot$. These results are in excellent agreement with previous substructure studies of this cluster.Comment: 18 pages, 10 figures, MNRAS accepted (7 Dec 2010

Relative susceptibilities of Brazilian vegetation to airborne fluoride

De todos os poluentes contidos na atmosfera, os fluoretos são os mais tóxicos para as plantas. Compostos tais como fluoreto de hidrogênio, tetrafluoreto de silicone e ácido fluossilícico são subprodutos usados na fabricação de alumínio, de fertilizantes fosfáticos, de aço, de vidro e de fluoroplásticos, e na combustão de carvão. Há muitas outras fontes de fluoreto, porém menos importantes. Além de ser altamente tóxico, o fluoreto se acumula nas folhas. Sua ingestão pelos animais herbívoros pode acarretar, em muitas espécies, a doença dos dentes e do esqueleto chamada "fluorose". Para o homem, a quantidade de fluoreto acumulado nas plantas apresenta menos perigo do que para os animais. A maior parte dele se encontra acumulado nas folhas; portanto, o consumo do caule, das sementes, dos frutos e das raízes não aumenta muito o fluoreto no organismo. No decurso de uma pesquisa de vegetação com visitas a quatro fundições de alumínio, no Brasil, em 1982, 83 e 86, mais de 230 espécies de plantas originárias de áreas tropicais, semitropicais e temperadas foram classificadas de acordo com sua relativa susceptibilidade ao fluoreto, com base no grau de danos causados nas folhas. Tal fato, contudo, não pode ser considerado como medida de desempenho de produção. As espécies são classificadas de acordo com a nomenclatura botânica padrão, juntamente com os nomes vernáculos usados no Brasil e nos Estados Unidos. Airborne fluorides are the most toxic of the common air pollutants to plants. Compounds such as hydrogen fluoride, silicon tetrafluoride, and fluosilicic acid are byproducts of the manufacture of aluminum, phosphate fertilizer, steel, glass, fluoroplastics, and of coal combustion, but there are also many other lesser sources. Fluoride is not only highly toxic but it also accumulates in the plant, especially in the foliage. Ingestion by herbivores can induce a dental and skeletal disease called "fluorosis" in many species. The fluoride accumulated in plants poses little danger to man because the amount of fluoride that might be ingested in the average diet would be relatively low compared with herbivores. Because most of the fluoride in plants accumulates in foliage, ingestion of stems, seeds and fruits, and roots should not increase fluoride significantly. During the course of inspecting vegetation at four aluminum smelters in Brazil in 1982, 1983 and 1986, more than 230 species of plants from tropical, semi-tropical, and temperate areas were ranked according to their relative susceptibility to fluoride, based upon the degree of foliar injury produced. This may not be a measure of yield response, however. Species are classified according to standard botanical nomenclature, along with the vernacular names used in Brazil and the U.S.