CFD simulations of a tunnel fire—Part II

The sensitivity of results of simulations of the area downstream of a fire in a tunnel to several factors was quantified. The factors were natural convective heat transfer, radiative heat transfer, wall roughness, downstream boundary position, slope and turbulence model. The results were most sensitive to natural convection, radiation and wall roughness. The results were not sensitive to which of the two turbulence models were used, nor to the position of the downstream boundary position. Overall uncertainties between the simulations were up to 60%, and temperatures were overpredicted in the base case by up to 75 K. The simulation carried out using a combination of factors gave maximum temperatures at the downstream end of the tunnel within 25 K of the experiments.     

CFD simulations of a tunnel fire—Part I

This paper concerns sensitivity studies of computational fluid dynamics (CFD) simulations of a fire in a tunnel. The simulations were of an experimental fire in a tunnel carried out by the Fire and Thermofluids Section of the Health and Safety Executive, Buxton, UK. The fuel used in the experiment was kerosine, the heat output rate was 2.7 MW and the tunnel was longitudinally ventilated. During the period of the experiment studied in the simulations, there was an upstream layer of approximate length 11 m. Simulations were carried out for two areas of the tunnel: the area around the fire and the area downstream of the fire. This paper describes the simulations of the area around the fire, whilst the accompanying Part II paper describes the area downstream of the fire. In the fire area simulations, the upstream propagating smoke layer length was found to be sensitive to the ventilation velocity, the ventilation velocity profile, the turbulence model used and the heat input rate. This case, in which the fire did not extend over the width of the tunnel, gave an upstream layer at higher ventilation velocities than those found in the literature. While reduction of the heat input rate to allow for radiative heat transfer from the flame caused a significant change in results, neither radiative heating of the tunnel ceiling nor the distribution of the fuel across the fuel pan had a significant effect on the results.     

‘Feeling a Door’ to see if fire is on the other side

This paper considers door assemblies that separate a fire environment from a protected space. It analyzes three methods of feeling a door on the protected side that can assist in determining the existence of a direct fire threat on the other side. These methods are: 1) feeling the door surface to determine whether or not it is at an elevated temperature; 2) feeling, smelling and visual inspection of the door edges to determine possible smoke flows from an adjacent fire environment; and 3) feeling the door-knob to determine whether or not it is at an elevated temperature. It is determined that a practical and effective strategy can be developed which uses all three methods to establish the existence of a fire threat without direct exposure to the fire environment. Of all methods discussed, the most reliable single indicator involves touching the base of the door-knob.     

A Summary of the Symposium of the International Housing Issue

The Ministry of Urban and Rural Con-struction and Environmental Protection(MURCEP) of China and the UN Centerfor Human Settlement jointly sponsored asymposium on the international housing is-sue from June 9 to 15,1987 in Kunming,China.The symposium was an importantevent co-sponsored by China and the U.N.Center for Human settlement in the Interna-tional Year of Shelter.lts main topic was:to     

A study on the fish fauna of Oussudu – a rare freshwater lake of South India

Oussudu lake (also called Ousteri) is the largest fresh water lake in the Pondicherry region and a large number of people depend on its water, fish and other produce. The lake is now under serious threat of pollution. The present study on the species, composition and dynamics of the lake fish was conducted in this context. Recommendations pertaining to the management of water quality and fisheries are presented on the basis of the studies described in this paper.     

A parametric study on the effects of displacer-cylinder-circumferential-wall thermal conditions on the performance of a γ-type LTD Stirling engine

ABSTRACT

Regarding a Stirling engine’s heat source and heat sink, most of the studies in the literature focus only on the magnitude of temperature difference between them. However, different Stirling engines adopt very different heat-source and heat-sink configurations. This study is aimed at understanding the effects of different displacer-cylinder-wall thermal conditions on engine performance using computational fluid dynamics (CFD). Results include p–V diagrams, heat flux distributions, temperature variations, and effects of three displacer-cylinder-wall parameters on indicated power and efficiency. It is found that the thermal conditions on the displacer-cylinder-circumferential wall (DCCW) impose significant effects on engine performance. Within the ranges of parameters investigated in this study, extending the coverage of heat source and heat sink on this wall improves up to 28% in indicated power at the cost of losing about 10% in efficiency, proving the significance of DCCW conditions on engine performance.     

On the Special Features of a City

1 .The Aesthetie Charaeteris-ties of a City Eaeh entity Possesses its unique eharae-teristies,and its Peeuliarities in its aPPear-anee whieh can easily lead to its reeognitionand dil'f七rentiation from others;the term,'featurel' 15 frequently used to refer to suchpercePtible eharacteristi     

Building a GIS Platform for Sustainable Land Management: A Case Study of the City of Čačak,Serbia

The general aim of this research is to contribute to sustainable land management and urban planning practices. An approach for building an urban planning-oriented information platform that could support a sustainable (i.e. environmentally sustainable), socially responsible and economically efficient decision-making process in the future at the municipal level is proposed. The proposed information platform approach relies on and is built for the Geographic Information System (GIS) but includes basic data management principles and the standards of the Spatial Data Information (SDI) concept, namely, INSPIRE. Thus, a model with the two following technical elements for building land management and urban planning based on a general platform or database is proposed in this article: (1) a conceptual Unified Modeling Language (UML) data model for urban planning metadata and data for different types of urban plans and (2) lists of land-use classes and types at the municipal level (included in the UML data model). The proposed approach includes a land-use model and the standardization of urban planning data to build a GIS platform to better integrate various types of data (social, economic, environmental, etc.) and is based on general and detailed urban regulation plans and land governance practices in the City of ?a?ak, Republic of Serbia. Once implemented, the proposed approach is expected to create preconditions for decision making regarding future sustainable land development in ?a?ak and other municipalities in Serbia.     

Unmanaged heathland – A fire risk in subzero temperatures?

Parameters leading to the severe Flatanger and Frøya (Norway) January 2014 subzero wildfires, respectively burning 15 km² and 10 km² Atlantic heathlands (dominated by heather, Calluna vulgaris) and destroying 64 structures, have been analyzed. Traditional heathland management, including anthropogenic fire regimes, had not been performed in these areas over the last 50+ years. As a result, the vegetation composition consisted of degenerated old and woody Calluna stands, bushes and shrubs, with high amounts of accumulated (live and dead) biomass. Adiabatically heated subzero temperature easterlies dried the Calluna stands. When ignited, the lack of snow cover and the strong winds resulted in rapid fire spread. Rugged terrain, few hours of daylight at 64.4°N and the lack of roads and manmade fire lanes made controlling the fires very challenging. Drying experiments were conducted to learn how quickly Calluna plants dry at 20°C and 50% relative humidity from rain-wet conditions. Based on the surprisingly rapid drying of the lower (dead) canopy, vapor pressures and diffusion theory, it is concluded that the Flatanger and Frøya Calluna stands represented a severe fire risk within two days of exposure to 50% relative humidity air at 0°C. Young and more vigorous plants in the building phase (6–15 years old), as well as freeze drought damaged (typically some dead small branches) old but still live plants, showed different drying characteristics and dried more slowly. When understanding how degenerated Calluna stands, from Portugal to the Arctic Circle, dry in the wintertime, warnings may be issued when appropriate. This paper may also serve as input to discussions regarding the several-thousand-year tradition of prescribed burning versus potential raging wildfires in unmanaged Calluna stands.     

A Primary Analysis of the Morphology Formation of the Market Towns in the Region of Rivers and Lakes to the South of the Lower Reaches of the Yangtze River

The market towns in the region of riv-ers and lakes to the south of the lowerreaches of the Yangtze River in China havelong focussed people's attention upon theirunique formal structures.In this region ofrivers and lakes,its natural morphology is in     

Effect of Physical Environment on the Behaviors of Residents with Dementia： A Comparison between a Small-Group Unit and a Traditional Care Unit

This is a comparative study examining the influence of a small-scale dementia unit and a traditional dementia unit on behaviors of the residents. The small-scale unit and the traditional unit were selected through two phases in Vancouver, Canada. Seven residents from each facility completed the study. Physical environmental assessments were performed using two tools： PEAP （professional environmental assessment protocol） and TESS-NH （therapeutic environment screening survey for nursing homes）. For the assessment of residents＇ behaviors, three assessment tools were used： MOSES （multidimensional observation scale for elderly subjects）, MDS （minimum data set） and DCM （dementia care mapping）. The study found that the residents living in a small-scale environment were more engaged in activities and more likely to respond in understanding their fellow residents. Residents living in a traditional long-term care exhibited fewer signs of social interaction. The findings suggest that a small-scale homelike environment could positively influence people with dementia to be more engaged in social exchanges and activities, and consequently help in reducing their withdrawn behavior.     

Response of steel beam–columns exposed to fire

Steel beams when exposed to fire develop significant restraint forces and often behave as beam–columns. The response of such restrained steel beams under fire depends on many factors including fire scenario, load level, degree of restraint at the supports, and high-temperature properties of steel. A set of numerical studies, using finite element computer program ANSYS, is carried out to study the fire response of steel beam–columns under realistic fire, load and restraint scenarios. The finite element model is validated against experimental data, and the importance of high-temperature creep on the fire response of steel beam–columns is illustrated. The validated model is used to carry out a set of parametric studies. Results from the parametric studies indicate that fire scenario, load level, degree of end-restraint and high-temperature creep have significant influence on the behavior of beams under fire conditions. The type of fire scenario plays a critical role in determining the fire response of the laterally-unrestrained steel beam within a space subframe. Increased load level leads to higher catenary forces resulting in lower fire resistance. Rotational restraint enhances the fire resistance of a laterally-unrestrained steel beam, while the axial restraint has detrimental effect on fire resistance.     

A Summary of the Academic Symposium on the Treatment and Management of City Wastes

With the continuous worsening of theproblems of urban wastes about 60 urbanscientific workers gathered in Guiyang to dis-cuss the present state of the treatment andmanagement of urban wastes and find rela-tive solutions to the problems.The“Guiyang Symposium on the Treat-ment and Management of City Wastes”jointly sponsored by the Chinese Urban Sci-entific Research Institute,the Urban Con-struction Department of the Ministry of Ur-     

A study on the building of a new “output–output model” and its usefulness: based on a comparative analysis of the input–output model

This paper describes the building of a new open static “output–output” (O–O) model in comparison to the open static input–ouput (I–O) model developed by Leontief (Rev Econ Stat 18:105–125, 1936). While the I–O model can be characterized as a system that relates final demand to gross output, the O–O model relates gross output for final demand (endogenous or exogenous) to gross output for output (endogenous). We perform a comparative analysis between the two models in structure and characteristics and illustrate the usefulness of the O–O model, for example, by formulating I–O multipliers that can accept output as an initial change. The comprehensive analysis conducted in this paper, including a numerical illustration with an example, shows that the two models form a mutually supplementary relationship and could give rise to a fundamental framework for the analyses of various regional and national economic activities.     

A consideration of the “no-black-hole” condition

The purpose of this paper is to investigate the economic interpretation of the no-black-hole condition (NBHC) described in the Chapt. 4 of the book by Fujita, Krugman and Venables (1999), under the context of a more general model. The main findings are as follows. First, there is the case in which the NBHC does not hold even though the real wage falls at the symmetric equilibrium. Secondly, the NBHC in the more general model requires both a reduction in profits in response to an increase in the number of firms and a fall in the real wage rate in response to an increase in labor at the symmetric equilibrium. Thirdly, we show that NBHCs obtained in some analyses are special cases of our model. Moreover, we show that the NBHC includes the stability condition for the short-run equilibrium. Therefore the NBHC is not affected by relative speed of labor movement and entry/exit of firms.Received: November 2002/Accepted: March 2004     

A Survey of the Residents''''Needs for Outdoor Activities

The Article is based on an on-the-spot investigation of the needs of the residents.Visits were made to obtainin-depth understanding about the patterns in the outdoor activities.Survey results are analysed from many respectssuch as landscaping,noise,living facilities,security and building space,in order to probe into the issue of how tocreate good outdoor environment for the residents in the planning of residential areas.     

A Study of the Structure and the Functions of the Local Resident Organization in China''''s Urbanized Society

To set up self-rule organizations forsocial life of the mass at city's local level isnot uncommon in other countries.But toset up a resident committee of completestructure and with overall functions thatserves as an intermediate between the localpolitical organization and family units issomething peculiar to China.Then,how     

One & Other: a picture of the nation in a period of cosmopolitanism?

Is the form of the public monument viable today? A proliferation of monuments and memorials in Europe from the 1870s onwards articulated national identities for states of which many were either recently established or in decline. Representation of the nation was a unifying device. Today, the statues raised in past centuries fade into the urban landscape while a world of global capital and economic migration, in which cities compete globally regardless of the national territories in which they are situated, renders the idea of belonging fluid, and that of national identity perhaps defunct. A question arises as to whether the form of the monument (as a class of objects) retains currency, or can be democratised for a society of diverse publics and conflicting interests. This paper takes Antony Gormley's project for the vacant plinth in Trafalgar Square, London in the summer of 2009—One & Other—as a case by which to investigate the viability of the monument today. After describing the project and its performative character, I draw on three connected frameworks: the monument as representation; constructions of national identity; and the expediency of culture in masking social divisions. I cite Matthew Arnold's claim that culture is a defence against anarchy (his term for social breakdown), and link this to nineteenth-century reformism. This leads me to ask whether a reformist ethos still applies, and whether there are parallels between such cultural strategies and public art as a renewal of the monument in a period of widening social divisions.