none

In recent year, there were many fire accidents in MRT and subway station,due to faolure in smoke control system and emergency operation strategies. The goal of this project is to use two sofeware¡XFDS and Star-CD to simulate the fire in MRT station and predict the height of smoke layer and its descending rate .The comparison of the two indicated sucessful result can be obtained with deviations within engineering tolerance..

<p>Background</p><p>Strategic alliances have become increasingly popular within the business world, they can be seen as a way to improve the total output of the firm. Over the last 10 years, the industry endured trying times, the most notable being the events of September 11, 2001. That event drastically changed airline traveling all across the world. It also showed the importance of collaborations in order to stay competitive. Star Alliance began in 1997 and has since then grown into</p><p>the world’s largest airline alliance with a total market share of 25.1%.</p><p>Purpose</p><p>The raison d’être of this study is to quantify and analyze the augmentation of load factors over time, in terms of distribution, as they pertain to capacity performance of allied carriers within Star Alliance.</p><p>Method</p><p>In order to fulfill the purpose, a deductive approach to the research has been taken. Furthermore, due to the nature of the data, a quantitative approach has been used within. Two hypotheses will be stated and several research questions as well.</p><p>Result</p><p>It can be clearly seen that distribution of load factors has transformed during the years. There is a shift in both the skewness and the kurtosis of the distributions that can be seen when examining the frequency distribution charts. The kurtosis increases and the skew decreases, measures that are positive for the airlines, while the anomalies of 0% and 100% load factor have remained stable throughout the years. A general increase in the average load factors has also been seen.</p><p>Conclusion</p><p>By analyzing the empirical findings, it is clear that the load factor of the allied members has increased and that the proportion of the denied boardings decreased in relation to the average load factor. This means that the alternative hypothesis was accepted in the first hypothesis and that the second alternative hypothesis was accepted in the second hypothesis. The research also reveals a generally increased mean which together with the changes in the skew and kurtosis lead to an acceptance of the beta distribution. Furthermore, higher load factors were shown to have a strong correlation with the increase in efficiency and decrease in overselling.</p>

This study focuses on solutions for the specific issues experienced by the distance learning program at the Lone Star College System (LSCS), a multi-college community college district located north of the Houston metro area. Utilizing practical action research methodology, the purpose of this study is to explore options for improving the LSCS distance learning program to better meet the needs of current and future distance learning students. This study combines a review of literature, local insights concerning the LSCS distance learning program, and discussions with other community college distance learning practitioners around the country for the purpose of developing an administrative proposal for the LSCS distance learning program. The study involves an exploration of the administrative and governance structure, a review of services provided to distance learning faculty and students, and an examination of quality standards for online courses and services. / text

In this thesis, I explore the rate at which molecular gas is converted to stars through detailed studies of a sample of molecular clouds in the Milky Way, IFU spatially resolved observations of gas-rich nearby interacting galaxies, as well as the environmental dependence of star formation and galaxy morphology in a galaxy supercluster. This thesis is composed of three individual projects that investigate nearby star formation within the local 500 pc of our Sun, to neighboring extreme star forming environments of interacting starburst galaxies, and finally studying how star formation varies with galaxy morphology in a galaxy supercluster a z~0.165. I discuss the relation between the star formation rate (SFR) and molecular gas surface densities (e.g., Schmidt-Kennicutt relation) in Galactic star forming regions and find there is a discrepancy between my study and extragalactic relations. The discrepancy is attributed to extragalactic measurements that are averaged over large >kpc scales and include star forming molecular gas (above some threshold) and molecular gas the is not dense enough to form stars. I find a steep increase in the Galactic SFR-gas surface density relation indicative of a threshold for efficient star formation that is best fit to a broken power law with a linear slope above 129 Msun pc⁻². I introduce the VIRUS-P Investigation of the eXtreme ENviroments of Starbursts (VIXENS) project which is a survey of interacting is a large integral field unit survey of nearby infrared bright (L_IR>3x10¹⁰ Lsun) interacting/starburst galaxies. The main goal of VIXENS is to investigate the relation between star formation and gas content on spatially resolved scales of ~0.1-1 kpc in the extreme star forming environments of interacting/starburst galaxies. The VIXENS sample is composed of systems in a range interaction stages with morphological signatures from early phase (close pairs) to late stage mergers (single system with multiple nuclei), SFRs, and gas surface densities. I highlight the first results from the VIXENS survey in the late interaction phase galaxy merger Arp 299. I find 1.3 kpc regions in Arp 299 to lie along the SFR-gas surface density relation found for mergers at high redshift, but this relation is highly dependent on the CO to molecular hydrogen (H₂) conversion factor. I find evidence for a Galactic CO-to-H₂ conversion factor using metallicity and dust temperature measurements, which would place 1.3 kpc regions in the Arp 299 merger in between the high redshift and Kennicutt-Schmidt relations. Comparing the SFR to dense gas surface densities as traced by HCN and HCO⁺, I find an agreement between the spatially resolved measurements and that found on global scales in spirals and (ultra)luminous infrared galaxies. Finally, I present an investigation of the influence of environment on frequency, distribution, color, and star formation properties of galaxy mergers and non-interacting galaxies in the Abell 901/902 supercluster at z~0.165. I find galaxy mergers be preferentially blue in color and have an enhanced SFR by a factor of ~2 compared to non-interacting galaxies. This result may be due to a decrease in galaxy velocity dispersion in the cluster outskirt, favoring galaxy-galaxy interactions, or to interacting galaxies that are part of groups or field galaxies being accreted along cosmological filaments by the clusters. I compare to N-body simulations of groups and field galaxies accreting onto the clusters and find the fraction of mergers are similar to that predicated at group overdensities. I find the SFR of galaxies in the supercluster to be depressed compared to field galaxies in both the core and cluster outskirts, suggesting that an environmental process such as ram pressure stripping is effective throughout the cluster. The results of a modest SFR enhancement and a low merger fraction culminate in my finding that mergers contribute only a small fraction (between 10% and 15%) of the total SFR density of the Abell 901/902 clusters. / text

For over a decade studies of the strong interaction in extremely dense nuclear environments have been done at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. It is hypothesized that colliding two beams of Au nuclei at relativistic speeds creates an environment of hot dense nuclear matter where the quarks and gluons inside the nucleus, which are normally confined within the protons and neutrons, become deconfined into a soup called the quark-gluon plasma. Since direct observation of this short-lived phase is impossible, many sophisticated analysis techniques attempt to study the early interactions via the final state particles. What has emerged from analyses of the data are two, contradictory paradigms for understanding the results. On the one hand the colliding quarks and gluons are thought to strongly interact and reach thermal equilibrium. The other view is that primary parton-parton scattering leads directly to jet fragmentation with little effect from re-scattering. It is in principle possible to distinguish and perhaps falsify one or both of these models of relativistic heavy ion collisions via the analysis of two-particle correlations among all charged particles produced in [mathematical symbols] = 200 GeV Au+Au collisions at the STAR experiment at RHIC. This dissertation presents studies of two-particle correlations, whose derivation can be traced back to Pearson's correlation coefficient, in transverse momentum and angular space. In momentum space a broad peak is observed extending from 0.5-4.0 GeV/c which, as a function of nuclear overlap, remains at a fixed position while monotonically increasing in amplitude. Comparisons to theoretical models suggests this peak is from jet fragmentation. In a complementary study the momentum distribution of correlations in ([eta],[phi]) space is investigated. The momentum distribution of correlated pairs that contribute to the peak near the origin, commonly associated with jet fragmentation, is peaked around 1.5 GeV/c and does not soften with increased centrality. These measurements present important aspects of the available six dimensional correlation space and provide definitive tests for theoretical models. Preliminary findings do not appear to support the hypothesis of a strongly interacting QGP where back-to-back jets are expected to be significantly suppressed. / text

One of the most fundamental and critical functions of embryological development is the control and regulation of differential genes and gene networks. The study of the gene networks involved in development is a mechanism for understanding the developmental process at its most basic level. An evolutionary change in a morphological feature or features must depend on a reorganization or co-option of one or more developmental gene regulatory network just as retention of an ancestral morphological trait must rely on retention of a common gene regulatory network. Studying two closely related classes in the same phylum with the same essential morphological feature yet with unique developmental characteristics provides insight into the evolution of these evolutionarily resolute gene regulatory networks. We have developed a new model system using brittle stars to further these studies. In this investigation I have identified key genes of the gene regulatory network (GRN) found in embryonic endo-mesoderm development in the sea urchin, responsible for embryonic skeletogenesis, and compared these key genes with homologues in the brittle star. From the examination of two closely related gene regulatory networks found in two related classes of Echinoderms insight can be gained into the foundation of morphological change over time.

In this thesis, I explore both obscured and unobscured star formation over a large fraction of cosmic time. I use the HAWK-I Y -band science verification data over GOODS-South, in conjunction with optical and infrared data to search for Lyman-break galaxies at z >∼ 6.5 (i.e. within the first billion years of the Universe). I find four possible (two robust) z′-drop candidates (z >∼ 6.5) and four possible (but no robust) Y -drop candidates (z >∼ 7). I use my results to place constraints on the luminosity function at z ∼ 6.5 and find significant evolution in the population of Lyman-break galaxies between 3 < z <∼ 6.5. I also explore obscured star formation with a population of 70μm selected galaxies over the COSMOS field. I use AAT spectroscopy in conjunction with other available spectroscopic redshifts for my sample, and photometric redshifts otherwise, to calculate the total infrared luminosity of each galaxy. Two libraries of spectral energy distributions are considered; Siebenmorgen & Krügel (2007) templates and Chary & Elbaz (2001) models. We have supplemented our data with that of Huynh et al. (2007) collected over the GOODS-North field and adapted it to directly compare with the results of this work. The far-infrared luminosity function is then determined using the 1/Vmax technique. A double power law parameterisation is found to provide the best fit to the data. The far-infrared luminosity function was fitted for all parameters and the evolution was measured out to z ∼ 1. Three different types of evolution were allowed, pure luminosity, pure density and luminosity dependent density evolution. In all cases strong positive evolution was evident with the best-fit case being pure luminosity evolution where p = 2.4+0.6 −0.7. Due to the larger volume surveyed compared to previous studies, this work provides better constraints on the bright end of the far-infrared luminosity function displaying a shallower bright end slope (α2 ∼ −1.6) than previously determined, implying a higher number density of the most luminous objects and thereby a greater contribution from these objects to the total infrared energy density. However the shallower slope determined here can be reconciled with other work if the Chary & Elbaz (2001) models are used instead of the Siebenmorgen & Krügel templates; demonstrating that spectral energy distribution model selection is a key component in determining luminosity functions at far-infrared wavelengths. The far-infrared–radio correlation (FIRC; qIR) was determined for the sample of 70μm selected star-forming galaxies using 1.4GHz radio data over the COSMOS field, and no evolution was found out to z ∼ 2. The 70μm monochromatic evolution in the FIRC was also examined (q70) and no evolution was found in this parameter with redshift.

The Bolocam Galactic Plane Survey (BGPS) has surveyed the northern Galactic plane at 1.1 mm and detected 8,358 sources. The BGPS catalog is large enough to characterize the properties of massive star formation in a statistically significant way. In this dissertation, I have conducted a survey of NH₃ lines toward 771 BGPS sources located throughout the Galactic plane. The NH₃ and 1.1 mm continuum observations together have allowed for complete characterization of the physical properties of these sources. I detected the NH₃(1,1) line toward 408 BGPS sources in the inner Galaxy, allowing for determination of their kinematic distances. At distances less than roughly 1 kpc, the BGPS detects predominately cores which will form a single star or small multiple system, while at distances between 1 and 7 kpc the BGPS detects predominately clumps which will form entire stellar clusters. At distances greater than 7 kpc, the BGPS detects the large scale clouds which contain clumps and cores. I have correlated the BGPS catalog with mid-IR catalogs of massive young stellar objects (MYSOs), and found that 49% of the BGPS sources contain signs of active star formation. The masses, densities, H₂ and NH₃ column densities, gas kinetic temperatures, and NH₃ velocity dispersions are higher in BGPS sources with associated mid-IR sources. I have also studied the physical properties of the BGPS sources as a function of Galactocentric radius, R[subscript Gal]. I find that the mean radius and mass decrease with increasing R[subscript Gal] but peak within the 5 kpc molecular ring where the gas kinetic temperature reaches a minimum. The fraction of BGPS sources with associated mid-IR sources decreases by 10% within the molecular ring. I postulate that these trends can be explained by an ambient gas density which decreases with R[subscript Gal], but peaks within the molecular ring. Similarly, the NH₃ column density and abundance decrease by almost an order of magnitude from the inner to outer Galaxy. / text

The formation of the first stars, also known as Population III (Pop III), marked a pivotal point in the universe's evolution from relative smoothness and homogeneity to its current highly structured state. In this dissertation we study key aspects of Pop III star formation. We utilize three-dimensional cosmological simulations to follow the evolution of gas and DM from z ~100 until the first minihalo forms. Once the gas infalls toward the center of the minihalo and condenses, we implement the 'sink particle' method to represent regions that will form a star, and we follow the evolution of the metal-free, star-forming gas for many free-fall times. A disk forms around the initial Pop III star and fragments to form secondary stars with a range of masses (1 - 50 [solar mass]). This is markedly different from the previous paradigm of one single, massive star forming per minihalo. Using a ray-tracing technique, we also examine the effect of radiative feedback on protostellar growth and disk fragmentation. This feedback will not prevent the formation of secondary stars within the disk, but will reduce the final mass reached by the largest Pop III star. Measuring the angular momentum of the gas that falls onto the sink regions, we also find that the more massive Pop III stars accrete sufficient angular momentum to rotate at nearly break-up speeds, and can potentially end their lives as collapsar gamma-ray bursts or hypernovae. We furthermore numerically examine the recently discovered relative streaming motions between dark matter and baryons, originating from the era of recombination. Relative streaming will slightly delay the redshift at which Pop III stars first form, but will otherwise have little impact on Pop III star formation and the history of reionization. We finally evaluate the possible effect of a cosmic ray (CR) background generated by the supernova deaths of massive Pop III stars. A sufficiently large CR background could indirectly enhance the H₂ cooling within the affected minihalos. The resulting lower temperatures would lead to a reduced characteristic stellar mass (~ 10 [solar mass]), providing another possible pathway to form low-mass Pop III stars. / text