Would Two Dimensions be World Enough for Spacetime?

We consider various curious features of general relativity, and relativistic field theory, in two spacetime dimensions. In particular, we discuss: the vanishing of the Einstein tensor; the failure of an initial-value formulation for vacuum spacetimes; the status of singularity theorems; the non-existence of a Newtonian limit; the status of the cosmological constant; and the character of matter fields, including perfect fluids and electromagnetic fields. We conclude with a discussion of what constrains our understanding of physics in different dimensions.Comment: 31 pages, 1 figur

Smelting processes for silver extraction

The base metals used for the extraction of silver from its ores by smelting are lead and copper, and the different methods employed may be accordingly classified under the general headings of extraction by means of lead and extraction by means of copper --page 3

A GPU Implementation for Two-Dimensional Shallow Water Modeling

In this paper, we present a GPU implementation of a two-dimensional shallow water model. Water simulations are useful for modeling floods, river/reservoir behavior, and dam break scenarios. Our GPU implementation shows vast performance improvements over the original Fortran implementation. By taking advantage of the GPU, researchers and engineers will be able to study water systems more efficiently and in greater detail.Comment: 9 pages, 1 figur

AN EXPERIMENTAL ECONOMICS APPROACH TO ANALYZING PRICE DISCOVERY IN FORWARD AND SPOT MARKETS

Laboratory experiments are used to generate data that facilitate investigation of pricing behavior in forward and spot markets. Results suggest a tendency for prices in a spot market to converge to levels higher than those in a forward market. The difference in these market environments is the supply schedule. Buyers in a spot market are aware that supply is inelastic and become relatively aggressive bidders. Forward markets have a relatively elastic supply schedule and buyers fare better. This may motivate firms to promote forward markets and/or vertically integrate in the procurement of inputs.Experimental economics, Forward market, Price discovery, Spot market, Marketing,

Igneous Rock Associations 12. A Geologist’s Look at Archaeological Ceramics and Glass

Ceramics and glass represent synthetic metamorphic rocks and obsidian, respectively. Consequently, it is not surprising that many archaeologists have collaborated with geologists on projects dealing not only with lithic artifacts, but with ceramic and glass objects as well. This paper presents an overview of these latter two materials from a geological perspective, considering in turn how they are characterized and classified, their ages constrained, provenance and in some instances use determined, and how they were made. SOMMAIRELa céramique et le verre représentent respectivement des roches métamorphiques et l'obsidien synthétiques. En conséquence, il n'est pas étonnant que beaucoup d'archéologues aient collaboré avec des géologues sur des projets traitant non seulement des objets façonnés lithiques, mais également des objets en céramique et en verre. Ce document présente un aperçu de ces derniers deux matériaux d'une perspective géologique, considérant comment ils sont caractérisés et classifiés, leurs âges, provenances et emploies parfois déterminés, et comment elles ont été faites

A petrochemical study of basaltic layering at Henley Harbour, Labrador, using multidimensional scaling

Lack of internal textural evidence for flow tops and small chemical variability among late Proterozoic basalt samples suggest the presence of a single flow at Henley Harbour, Labrador, Canada, despite spectacular, m-scale layering in outcrop. Total chemical variation just slightly exceeds analytical uncertainty for many elements. Multidimensional scaling (MDS) enhances "effective" analytical precision by allowing all data (elements and samples) to be compared simultaneously. Scaling of elements reveals element associations/patterns consistent with igneous controls on distribution, even for alteration-sensitive (Na, K, Sr) elements. MDS also shows that the m-scale layering has a chemical fingerprint. However, to explain chemical variability between layers using mass balance calculations and averaged whole-rock data requires unreasonable (low temperature) phenocryst compositions. Textural features of the m-scale layering record changes in cooling regime between the bottom and center of the flow but chemical variation may reflect changing magma compositions during formation of an inflated flow. However, mass balance calculations suggest that large-scale chemical variation reflects the migration of residual liquid, perhaps as vesicle plumes, within an initially chemically homogeneous flow. Low in the flow (layer 1), metres-long but cm-scale raised and eroded subhorizontal "bands" superficially resemble segregation veins but lack coarse-grained textures. MDS confirms that raised and eroded samples are chemically distinct. Mass balance indicates that banding is not related to phenocryst percentages but may reflect the abundance of a residual liquid resembling the liquid explaining compositional variation between large-scale layers. Alignment of microlites and variations in the quantity of altered residual-liquid glass suggest that banding is related to magma movement during extrusion. It is possible that banding of this type has not been recognized before. RESUMÉ L'absence d'attestation texturale interne des sommets d'écoulement et la faible variabilité chimique entre les échantillons de basalte du Protérozoïque tardif laissent supposer la présence d'un écoulement unique à Henley Harbour, Labrador, Canada, malgré la stratification spectaculaire à moyenne échelle de l'affleurement. La variation totale des compositions chimiques dépasse tout juste légèrement l'incertitude analytique de nombreux éléments. L'analyse multidimensionnelle (AMD) améliore la précision analytique « effective » en permettant une comparaison simultanée de toutes les données (éléments et échantillons). L'analyse des éléments révèle des associations/dispositions d'éléments correspondant à des contrôles ignés de la répartition, même dans le cas des éléments sensibles à l'altération (Na, K, Sr). L'AMD révèle par ailleurs que la stratification à moyenne échelle présente une empreinte chimique. L'explication de la variabilité chimique entre les couches au moyen de calculs du bilan pondéral et de moyennes des données sur la roche totale nécessite cependant des compositions de phénocristaux excessives (basse température). Les caractéristiques texturales du fil de stratification à moyenne échelle changent en régime de refroidissement entre le fond et le centre de l'écoulement, mais la variation des compositions chimiques peut correspondre à des compositions magmatiques changeantes pendant la formation d'un écoulement gonflé. Les calculs du bilan pondéral laissent toutefois supposer que la variation des compositions chimiques à grande échelle témoigne de la migration de liquides résiduels, peut-être sous forme de panaches de vacuoles à l'intérieur d'un écoulement initialement homogène du point de vue chimique. Au bas de l'écoulement (première strate), des « bandes » subhorizontales de plusieurs mètres de longueur mais érodées et soulevées de quelques centimètres ressemblent superficiellement à des filons d'exsudation mais sont dépourvues de textures à grain grossier. L'AMD confirme que les échantillons soulevés et erodes sont chimiquement distincts. Le bilan pondéral révèle que le rubanement n'est pas lié au pourcentage de phénocristaux, mais qu'il témoigne de l'abondance d'un liquide résiduel ressemblant au liquide expliquant la variation des compositions entre les strates à grande échelle. L'alignement des microlites et les variations de la quantité de verre soluble résiduel altéré laissent supposer que le rubanement est apparenté à un déplacement magmatique survenu pendant l'extrusion. Il est possible qu'on n'ait pas décelé un rubanement de ce genre auparavant

Hardware Dispenser Project

The purpose of this design project was to develop a system that will allow employees of the ARC to be able to work on a greater variety of projects and to improve their productivity. The hardware dispenser group developed a design for a tray that would help the ARC employees work quicker and more efficiently. The tray has bins to hold hardware which the supervisor loads onto the tray. The employee slides a bag over the tip of the funnel and into the clip which holds the bag in place. The worker then chooses which parts need to be in the bag and slides each one of them down the tray from the bin and into the funnel. They can then remove the bag and the task is completed