Scale model test to estimate thermal damage by fire in aircraft cargo

The Federal Aviation Administration (FAA) requires fire detectors to alarm within one minute of the start of a fire in cargo compartments of airplanes. To determine whether such alarm timing works, investigations of the thermal damage to ceilings and other structures during the early stage of a fire were accomplished to demonstrate compliance with these FAA regulations. The objective was to test the feasibility of predicting convective heat transfer in early stage of a cargo compartment fire by conducting reduced scale (lab scale) experiments. First, the scaling laws was derived and validated. Then, full-scale and half-scale experiments were performed with attention to the heat fluxes from the fires. Similarity between the scaled tests were verified by matching dimensionless fire power profiles. Comparisons between the two-scale results showed good agreement in dimensionless heat fluxes to the ceiling and the rear bulkhead, thereby pointing to the capability of scale modeling as an effective tool for the present purpose

A strategy to predict the global warming gas from stock farming —Potential scaling law of the released methane from livestock—

This work examines a scaling approach to predict the amount of methane released from the daily activity of livestock on farms. The subject animals are ruminants, i.e. having rumen or a ruminant stomach, that generates methane through digestion processes via several microbial fermentation steps. The produced methane is mixed into their breathing and released into the atmosphere. Existing data on methane released from various kinds of ruminant livestock were correlated as a power function of an animal’s weight, with an exponent near 0.92. This value is larger than a value of 0.75 which was related to the general metabolism rates for various animals. These differences may be explained by structure differences of the digestive organs or, more precisely, the difference in the relative length of the small intestine against animal size. Smaller animals have relatively longer small intestines, suggesting that the digestive activity in their stomachs is relatively less-active with less methane production as compared to larger animals. Validity of these structurally-dependent hypothesis was examined and a scaling law is proposed. The derived scaling law can then be used to estimate the release of global warming gas from various kinds of livestock and help to consider reduction strategies to decrease this emitted methane

On correlations and mutual entropy in quantum composed systems

We study the correlations of classical and quantum systems from the information theoretical points of view. We analyze a simple measure of correlations based on entropy (such measure was already investigated as the degree of entanglement by Belavkin, Matsuoka and Ohya). Contrary to naive expectation, it is shown that separable state might possesses stronger correlation than an entangled state

Time Zones, Shift Working and Outsourcing through Communications Networks.

We build a trade model with two countries located in different time zones, a monopolistically competitive sector in which production requires differentiated goods produced using day and night labor, and shift working disutility. Consumers choose between working at a day shift or a night shift and firms may choose to “virtually” outsource foreign day time labor by using communications services. We found that the higher the disutility of working at night is, the smaller is the number of varieties produced. Trade is beneficial only under certain concavity and cost conditions. The higher the disutility of working at night, the larger can be the gains from trade

Time Zones, Shift Working and Outsourcing through Communications Networks.

We build a trade model with two countries located in different time zones, a monopolistically competitive sector in which production requires differentiated goods produced using day and night labor, and shift working disutility. Consumers choose between working at a day shift or a night shift and firms may choose to “virtually” outsource foreign day time labor by using communications services. We found that the higher the disutility of working at night is, the smaller is the number of varieties produced. Trade is beneficial only under certain concavity and cost conditions. The higher the disutility of working at night, the larger can be the gains from trade

Time Zones, Shift Working and International Outsourcing

We build a trade model with two identical countries located in different time zones and a monopolistically competitive sector of which production requires differentiated goods produced in two successive stages. We introduce shift working disutility and allow consumers to choose between day and night shifts. Shift working disutility raises the cost of night production and firms can reduce costs by “virtually” outsourcing foreign labor. We found that firms only outsource if relative costs of outsourcing are low and shift disutility is high. When outsourcing occurs under free trade, it generates the highest level of welfare among production modes. An intermediate range of shift working disutility can generate the lowest level of welfare and be not affected by the reduction of outsourcing costs

Time Zones, Shift Working and International Outsourcing

We build a trade model with two identical countries located in different time zones and a monopolistically competitive sector of which production requires differentiated goods produced in two successive stages. We introduce shift working disutility and allow consumers to choose between day and night shifts. Shift working disutility raises the cost of night production and firms can reduce costs by “virtually” outsourcing foreign labor. We found that firms only outsource if relative costs of outsourcing are low and shift disutility is high. When outsourcing occurs under free trade, it generates the highest level of welfare among production modes. An intermediate range of shift working disutility can generate the lowest level of welfare and be not affected by the reduction of outsourcing costs

Fingering behavior of flame spread over solid combustibles

In this study, the fingering pattern formation and the following flamelet spreading over three different kinds of thick combustibles, i.e., Poly methacrylate (PMMA), Poly ethylene (PE) and Poly carbonate (PC) were observed and the effective Lewis number correlation was validated. Experiments were performed with a narrow channel apparatus. In addition to the kinds of solid fuel materials, the channel height and the oxidizer velocity were varied as experimental parameters. An image analysis method was developed to quantify the number, diameter and spread rate of the flamelets. Replacing the fuel thickness into the thermal thickness, the effective Lewis number which is proposed for the smoldering combustion of thin fuel is remedied to include heat transfer perpendicular to the fuel surface. The result validates that the appearance condition of the fingering instability for thick combustibles is determined by the effective Lewis number. Hence, it is concluded that the observed phenomenon is inherently similar to that of smoldering. Further, it is shown that the non-dimensional flame diameter becomes nearly constant when the fingering instability occurs. It is believed that the correlation is useful when one wants to reproduce this phenomenon in a larger scale experiment

Short germ insects utilize both the ancestral and derived mode of Polycomb group-mediated epigenetic silencing of Hox genes

In insect species that undergo long germ segmentation, such as Drosophila, all segments are specified simultaneously at the early blastoderm stage. As embryogenesis progresses, the expression boundaries of Hox genes are established by repression of gap genes, which is subsequently replaced by Polycomb group (PcG) silencing. At present, however, it is not known whether patterning occurs this way in a more ancestral (short germ) mode of embryogenesis, where segments are added gradually during posterior elongation. In this study, two members of the PcG family, Enhancer of zeste (E(z)) and Suppressor of zeste 12 (Su(z)12), were analyzed in the short germ cricket, Gryllus bimaculatus. Results suggest that although stepwise negative regulation by gap and PcG genes is present in anterior members of the Hox cluster, it does not account for regulation of two posterior Hox genes, abdominal-A (abd-A) and Abdominal-B (Abd-B). Instead, abd-A and Abd-B are predominantly regulated by PcG genes, which is the mode present in vertebrates. These findings suggest that an intriguing transition of the PcG-mediated silencing of Hox genes may have occurred during animal evolution. The ancestral bilaterian state may have resembled the current vertebrate mode of regulation, where PcG-mediated silencing of Hox genes occurs before their expression is initiated and is responsible for the establishment of individual expression domains. Then, during insect evolution, the repression by transcription factors may have been acquired in anterior Hox genes of short germ insects, while PcG silencing was maintained in posterior Hox genes