Vicinity Of Buildings Research Articles

ORCA: A Tool for Radiological Consequences for Accidental Releases

Evaluating atmospheric dispersion and radiological doses in the vicinity of buildings is required for small modular reactors (SMRs) because of the reduced size of their exclusion area boundary. The current Canadian nuclear industry tool for these calculations implements the methodology defined in CSA Standard N288.2-M91, which was written to support large Canada Deuterium Uranium (CANDU) nuclear reactors as opposed to SMRs. The ORCA (On/offsite Radiological Consequences of Accidents) code has been developed to address this technical concern in addition to evaluating atmospheric dispersion and doses in the far field. The code calculates worker and public doses following an airborne release of radioactive material into the atmosphere under postulated accident conditions at a nuclear facility. The current paper presents the key assumptions and methods utilized in ORCA and discusses qualification of the software to the requirements of CSA Standard N286.7-16. The new model is applicable to SMRs and existing reactor designs and reduces conservatisms in the near field (i.e., <1 km from the source) relative to the methods in CSA N288.2-M91.

Method for selecting ornamental species for different shading intensity in urban green spaces.

In urban areas, ornamental plants face different constraints, such as the shading of buildings and trees. Therefore, the selection of suitable species and their integration or combination with pre-existing plants is very important. Trees, shrubs, and herbaceous plant species must be distributed according to plant light requirements and shading intensity. Ornamental plants are classified into two groups based on their light intensity or shade tolerance: sun and shade species. To properly position the plants, especially in the immediate vicinity of buildings, it is necessary to study the projection of shadows during the year and the most critical periods, such as July and August. The position of ornamental species with different shading tolerances can be obtained by characterizing the leaf gas exchange for each species. Among the physiological parameters, the most important is the light compensation point, which is the light intensity corresponding to a net photosynthesis equal to zero. This means that the assimilation of carbon dioxide through photosynthesis is equal to the carbon dioxide emitted by respiration. This steady state represents the most critical condition for plants to endure the summer. The distribution of species inside a green area should be determined by considering the minimum light intensity that allows sufficient photosynthesis to compensate for the respiration rate. In this context, non-destructive leaf gas exchange, chlorophyll a fluorescence, and chlorophyll content can be useful tools for selecting suitable ornamental plants under diverse shading conditions.

Gusts Encountered by Flying Vehicles in Proximity to Buildings

There is a growing desire to operate Uncrewed Air Vehicles (UAVs) in urban environments for parcel delivery, and passenger-carrying air taxis for Advanced Air Mobility (AAM). The turbulent flows and gusts around buildings and other urban infrastructure can affect the steadiness and stability of such air vehicles by generating a highly transient relative flow field. Our aim is to review existing gust models, then consider gust encounters in the vicinity of buildings as experienced by flight trajectories over the roof of a nominally cuboid building in a suburban atmospheric boundary layer. Simplified models of fixed- and rotary-wing aircraft are used to illustrate the changes in lift and thrust experienced by flight around the building. The analysis showed that fixed-wing aircraft experienced a substantial increase in angle of attack over a relatively short period of time (&lt;1 s) as they fly through the shear layer at a representative forward velocity, which can be well above typical stall angles. Due to the slow flight speeds required for landing and take-off, significant control authority of rotor systems is required to ensure safe operation due to the high disturbance effects caused by localized gusts from buildings and protruding structures. Currently there appears to be negligible certification or regulation for AAM systems to ensure safe operations when traversing building flow fields under windy conditions and it is hoped that the insights provided in this paper will assist with future certification and regulation.

Structural Diagram of Vibration Protection Means of Building Structures with Moving Loads

The methods of modeling the process of choosing methods and means of vibration protection for building structures with moving loads are considered based on a review of the literature on this topic. Structural analysis of vibration protection devices for building structures was carried out. Various options for reducing the negative impact of external influences in each specific case are proposed. Currently, building structures and buildings in general are under the influence of a significant number of sources of undesirable vibrations, both natural and technogenic. For example, in residential and public buildings the number of pumps, fans, air conditioners has increased, a large number of different machines, mechanisms and equipment is used. In the process of construction, as well as repair and reconstruction, the building is subjected to shock, mass (static), vibration and other effects. The increase in the number of transport and transport networks (which themselves are systems with moving loads) passing in the immediate vicinity of buildings and structures also affect them, both acoustically and mechanically. High-rise buildings are exposed to the force of the wind, buildings located in seismically hazardous areas - to seismic effects. It should be noted that the vast majority of vibration sources can be reduced to moving loads. Thus, at present, the task of reducing the impact of moving loads on building structures, and the resulting adverse factors (noise, oscillation, vibration, etc.) for comfortable living and human life is relevant. To protect buildings and structures from various types of moving loads and adverse factors, protection systems are provided. The system of building structure protection from various negative impacts can be conditionally divided into built-in and special. For example, fixed building structures can be designed in such a way that they are tuned mass dampers that protect high-rise buildings from the force of wind; engineering systems provide for the installation of noise suppressors on air ducts, noise-absorbing panels, the use of vibration isolation, vibration bases, floating floors, etc. when installing various equipment. Special measures may include the installation of special protective devices on pipelines, such as resonant wave process stabilizers, magnetorheological devices, etc. To select the most appropriate means of vibration protection for building structures with moving loads, it is proposed to use the methods of functional-structural analysis.

Asbestos cement products and their impact on soil contamination in relation to various sources of anthropogenic and natural asbestos pollution

The results of a quantitative analysis of asbestos content in the ground with varying degrees of concentration of this mineral as a result of natural phenomena such as rock weathering, contamination by the manufacture of asbestos and cement products, and the many years of use of “eternit roofs” are presented. Preliminary thermal treatment, soil grinding and sieving were used for the determinations, followed by electrostatic separation in order to obtain the concentration of asbestos in a smaller volume. It was used for microscopic preparations for the identification and planimetry of asbestos. A polarizing optical microscope was used in the qualitative and quantitative analysis. The levels of re-emission of asbestos dust into the air as a result of the exploitation of contaminated soil were estimated. Polluted land in industrially areas, at a distance of up to 1200 m, contains 0.0003 % to 0.02 % asbestos. The content of 0.01 % asbestos does not require remediation in the absence of soil use. It may cause <500 fibres/m3. Removing the facade of asbestos-cement panels from the building at a distance of up to 10 m resulted in concentration <0.007 % of free asbestos in the ground, and for used roofs <0.001 % from above the distance of 3 m. This means that land in the vicinity of buildings with facade or roofing made of a-c products can be safely exploited. The direct discharge of rainwater from the gutter into the ground, however, contaminates it well above this value and those places should be treated as hazardous waste due to the presence of asbestos fibres in unbound form, containing <9,8 %. Ultimately, the size of the threat depends on many factors and can be comparable with the pollution of industrial production.

Large Eddy Simulation of HAWT and VAWT performances in the vicinity of a building

This work compares the performances of a Horizontal Axis Wind Turbine (HAWT) and a Vertical Axis Wind Turbine (VAWT) using Wall modeled Large Eddy Simulation (WMLES) coupled with an actuator line method. The wind turbines are located in the vicinity of a real size industrial building. Both wind turbines are sized to produce the same power at their respective optimum Tip Speed Ratio for a same incident wind speed. Two relevant incident wind directions (SW and SSW) are investigated, the influence of the building on the performance of the two wind turbines is also analysed. The results obtained show that the HAWT has a better overall performance compared to the VAWT. Overspeeds are observed for both directions analysed, due to the presence of the building which locally increases the flow velocity. However, these overspeeds remain low due to the low height of the building. The change of wind direction only slightly impacts the HAWT production, while the VAWT production remains insensitive. However, the presence of the building improves the global production of both wind turbines. Qualitatively, this change of wind direction induces a deviation in the wake of both turbines, which is greater for a SW direction.

Building detection using a dense attention network from LiDAR and image data

Accurate building mapping using remote sensing data is challenging because of the complexity of building structures, particularly in populated cities. LiDAR data are widely used for building extraction because they provide height information, which can help distinguish buildings from other tall objects. However, tall trees and bridges in the vicinity of buildings can limit the application of LiDAR data, particularly in urban areas. Combining LiDAR and orthoimages can help in such situations, because orthoimages can provide information on the physical properties of objects, such as reflectance characteristics. One efficient way to combine these two data sources is to use convolutional neural networks (CNN). This study proposes a CNN architecture based on dense attention blocks for building detection in southern Toronto and Massachusetts. The stacking of information from multiple previous layers was inspired by dense attention networks (DANs). DAN blocks consist of batch normalization, convolution, dropout, and average pooling layers to extract high- and low-level features. Compared with two other widely used deep learning techniques, VGG16 and Resnet50, the proposed method has a simpler architecture and converges faster with higher accuracy. In addition, a comparison with the two other state-of-the-art deep learning methods, including U-net and ResUnet, showed that our proposed technique could achieve a higher F1-score, of 0.71, compared with 0.42 for U-net and 0.49 for ResUnet.

"Is This Not the Τέκτων?": Revisiting Jesus’s Vocation in Mark 6:3

The term τέκτων in Mark 6:3 has received various interpretations, with "carpenter" and "woodworker" being the most prominent. However, a brief survey of the use of τέκτων in the LXX, Graeco-Roman, and early Jewish literature reveals that this term is more ambiguous than scholars have often argued and requires contextual clues for precise translation. Because of this, one must look to the socio-historical reality of a common Nazarene τέκτων in order to determine the best translation of τέκτων in Mark 6:3. Historical evidence, including recent archeological findings, indicates that a Nazarene τέκτων would have likely been expected to carry out a plethora of tasks in the vicinity of building and crafting. Thus, this article argues that the best translation for τέκτων in Mark 6:3 is "builder-craftsman."

GREENERY OF RESIDENTIAL COMPLEXES IN WROCŁAW – ANALYSIS OF SELECTED EXAMPLES

Green areas in cities have a different character. Apart from parks, an important role is played by estate greenery, which, due to its direct presence in the vicinity of buildings and apartments, has an impact on the quality of life and decisions made when buying a flat. The article compares greenery resources in six Wrocław housing estates, built in 1960–2010, i.e. at the turn of the 20th and 21st centuries. To assess the quality of greenery, an inventory of its resources was made. In order to assess social conditions, a survey was carried out among the inhabitants of the analyzed housing complexes. The greenery of the residential complexes from the 1970s and 1980s is diverse, rich especially in woody species, although it is not consistent in terms of composition. There are often plantings introduced by residents, probably as a substitute for home gardens and an element of "taming" the space. Greenery in the estates from the 21st century has a high aesthetic and compositional value. Plantings of shrubs and perennials prevail. The inhabitants' lack of creativity in planting their own is visible.

CFD Methods in Architecture and City Planning

The paper provides an overview of CFD solutions for architectural design and urban planning. Aspects of numerical modelling of the aerodynamics of buildings and structures are described. Examples of the influence of turbulence models on flow parameters in the vicinity of buildings, as well as examples of influence of thermal stratification regimes on flow structure around buildings and on concentration of gaseous emissions from low sources in the vicinity of these buildings are considered. The calculation results of aeration of a city micro-district and a scenario for the arrangement of green areas to change the wind regime of the territory with the already existing development are demonstrated in the paper.

Possibilities for using solar energy to fulfil the energy needs of buildings in the city centre

Historical buildings in the centre of European cities are characterized by compact built-up areas with diversified heights of buildings, most often with multi-sloped roofs. Architectural elements, dormers, chimneys and bay windows, cause limitations in the availability of surface area for solar installations. The paper presents the results of an analysis for possibilities in meeting energy requirements with the use of solar energy for old-town buildings in the centre of Bydgoszcz. Based on the calculations made, it was determined that the dense downtown development has a very large roof surface, however, the vicinity of buildings, roof slope angles, and obstacles cause significant restrictions on the location of such installations. The article analyzes selected fragments of the Downtown district. The height of buildings, their shape and the surface of their roofs and all the obstacles that occur there were taken into account. The conclusions concern an assessment of the possibility of using the potential of solar energy in this type of building. The efficiency of solar installations and the losses associated with energy conversion and transmission to customers is also included.

Evaluation of high-resolution GRAMM–GRAL (v15.12/v14.8) NO&amp;lt;sub&amp;gt;&amp;lt;i&amp;gt;x&amp;lt;/i&amp;gt;&amp;lt;/sub&amp;gt; simulations over the city of Zürich, Switzerland

Abstract. Hourly NOx concentrations were simulated for the city of Zürich, Switzerland, at 10 m resolution for the years 2013–2014. The simulations were generated with the nested mesoscale meteorology and micro-scale dispersion model system GRAMM–GRAL (versions v15.12 and v14.8) by applying a catalogue-based approach. This approach was specifically designed to enable long-term city-wide building-resolving simulations with affordable computation costs. It relies on a discrete set of possible weather situations and corresponding steady-state flow and dispersion patterns that are pre-computed and then matched hourly with actual meteorological observations. The modelling system was comprehensively evaluated using eight sites continuously monitoring NOx concentrations and 65 passive samplers measuring NO2 concentrations on a 2-weekly basis all over the city. The system was demonstrated to fulfil the European Commission standards for air pollution modelling at nearly all sites. The average spatial distribution was very well represented, despite a general tendency to overestimate the observed concentrations, possibly due to a crude representation of traffic-induced turbulence and to underestimated dispersion in the vicinity of buildings. The temporal variability of concentrations explained by varying emissions and weather situations was accurately reproduced on different timescales. The seasonal cycle of concentrations, mostly driven by stronger vertical dispersion in summer than in winter, was very well captured in the 2-year simulation period. Short-term events, such as episodes of particularly high and low concentrations, were detected in most cases by the system, although some unrealistic pollution peaks were occasionally generated, pointing at some limitations of the steady-state approximation. The different patterns of the diurnal cycle of concentrations observed in the city were generally well captured as well. The evaluation confirmed the adequacy of the catalogue-based approach in the context of city-scale air pollution modelling. The ability to reproduce not only the spatial gradients but also the hourly temporal variability over multiple years makes the model system particularly suitable for investigating individualized air pollution exposure in the city.

Numerical investigation of anchored soldier pile wall performance in the presence of surcharge

An anchored soldier pile wall is used for deep excavation stabilisation in the vicinity of buildings which are sensitive to displacement. In the current study, a three-dimensional model of anchored soldier pile wall was created in Abaqus software to estimate displacement and internal forces, especially due to surcharge. The effects of soil type, wall height, spacing of anchors and soldier pile rigidity were analysed. The results indicate that the surcharge had great effect on the wall deformation and the bending moment of the soldier piles; however, the bending moment of the lagging was less influenced by the surcharge.

Analysis of the blast-induced vibration structure in open-cast mines

Blasting in opencast mines is characterized by the use of large masses of explosives for a single blast. Blasting is done in a series of several to tens or even hundreds of charges placed in long holes and fired with a millisecond delay. Works are often carried out in the vicinity of buildings; therefore, reducing vibration impact is essential for opencast mines. This paper presents the applicability of the method of time-frequency Matching Pursuit (MP) for analysis of vibration structure. The use of MP analysis enables the development of much deeper and more reliable impact assessments of blasting on the environment.

Underground explosions: estimating the safe distance

Underground explosions may contain an even more devastating potential than comparable free explosions in air, because they can produce significantly greater pressures and stronger momenta and the explosive waves may decay more slowly with increasing distance. For civil applications such as clearance of explosive ordnance, explosive tunnelling and surface mining in the vicinity of buildings, a tool is desirable, with which the safe distance r hor,safe, beyond which a building remains undamaged, may be evaluated in a fast and simple manner. The procedure to derive such a tool is exemplarily demonstrated for near-surface, underground explosions with a charge mass of 125 kg of trinitrotoluene, dry sand as foundation soil and a building with shallow foundation and no basement. Numerical simulations were carried out with the commercial hydrocode Autodyn. To track the explosion-induced wave up to sufficiently large distances, the modelling strategy called the ‘moving window’ was developed. With respect to the damage patterns, ‘air blast’, ‘foundation-induced excitation of the structure to vibrations’ and ‘inadmissible inclination of foundations due to subsidence’, the numerical time courses of the relevant wave parameters were evaluated. The result is one chart for the safe distance as a function of the explosive’s charge depth.

Dispersion modelling in Northrhine–Westphalia: regulations, guidelines and pragmatic approaches

In Germany the only regulation concerning dispersion modelling is found in Annex C of the Technical Instructions on Air Quality Control (TA Luft). It prescribes a Gaussian plume model but does not consider features such as wet deposition, dynamic plume rise and transport in structured terrain. Several VDI Guidelines have been formulated to harmonize handling of those features. However, concerning dispersion modelling in the vicinity of a source where the influence of buildings has to be taken into account, no general proposal has been made. As there are several models to calculate flow and concentration fields in the vicinity of buildings, first steps have been made in the State of Northrhine–Westphalia to find a pragmatic approach for using these models to determine annual means and percentiles. Thereby the number of different meteorological situations to be considered has to be reduced. The resulting coarser classification of wind speed, wind direction and stability classes must be based on the available meteorological frequency distributions.

Low Energy Source Synthetic Thermal Energy Storage (STES)

The team of Building environment in VŠB-Technical university of Ostrava works intensively on options in long-term accumulation of heat in underground storages. The new concept follows the Directive of the European Parliament and of the Council 2010/31/EU on the energy performance of buildings [1]. The Directive requires that energy should be extensively covered of renewable sources produced at or in the vicinity of building, where it will be consumed. The aim of the research is create thermal energy storage with model structure for complex of family house. For the storage will be used recycled materials especially recycled concrete. This system will be heat source in winter period and heat consumer in summer period.

Forest vegetation structure has more influence on predation risk of artificial ground nests than human activities

As a major process affecting the reproductive success of birds, nest predation influences population density and dynamics and forces species to adapt to ecological and evolutionary time scales. The disentangling of potential natural and anthropogenic drivers of nest predation is crucial for the conservation of species. Thus, we investigated the effects of elevation, egg characteristics, vegetation structure and human activities on daily nest predation rates of artificial ground nests by baiting 700 artificial nests with quail eggs along an elevational gradient of about 1100m. After 25 days, we found an overall daily nest predation rate of 0.045. Our generalized linear mixed model revealed increasing daily predation rates with increasing forest management, no impact of recreational activities, and lower daily predation rates in the vicinity of buildings. Furthermore, daily predation rates declined with increasing density of near-ground vegetation and increased with increasing tree cover. Finally, we found no influence of elevation, matching of egg and ground colouration, and dead wood on daily nest predation rates. Our results revealed that the risk of nest predation depends more on vegetation structure than on current levels of recreational activities. Moreover, the negative relation of nest predation risk and near-ground vegetation indicates that the changing forest structure after natural disturbances (e.g. wind throw or bark beetle infestation), which is tolerated within the benign neglect strategy applied by the authorities of protected areas, decreases the predation risk, whereas salvage logging increases this risk.

A numerical analysis of the influence of tram characteristics and rail profile on railway traffic ground-borne noise and vibration in the Brussels Region

Nowadays, damage potentially caused by passing train in dense cities is of increasing concern and restricts improvement to the interconnection of various public transport offers. Although experimental studies are common to quantify the effects of noise and vibration on buildings and on people, their reach is limited since the causes of vibrations can rarely be deduced from data records. This paper presents the numerical calculations that allow evaluating the main contributions of railway-induced ground vibrations in the vicinity of buildings. The reference case is the Brussels Region and, more particularly, the T2000 tram circulating in Brussels city. Based on a pertinent selection of the vibration assessment indicators and a numerical prediction approach, various results are presented and show that the free-field analysis is often improperly used in this kind of analysis as the interaction of soil and structure is required. Calculated high ground vibrations stem from singular rail surface defects. The use of resilient wheels is recommended in order to reduce the ground-borne noise and vibration to permissible values.

The Influence of Surrounding Buildings on the Natural Ventilation Performance of Residential Dwellings in Hong Kong

Natural ventilation in residential dwellings is very important for occupants’ health and comfort. Previous studies by the authors have concluded that natural ventilation performance in dwellings can be enhanced by positioning the two groups of window openings (bedroom windows and living room windows) in opposite directions or perpendicular to each other; and/or the use of side-hung windows. However, the buildings selected for those studies were located in an isolated site, for the purpose of focused evaluation of the influence of various configuration parameters and window types. However, in Hong Kong, buildings are tightly packed. In this study, the influence of urban environment was thoroughly considered. A residential estate was identified to represent typical characteristics of the urban environment in Hong Kong for CFD modelling and simulations. Bi-variate correlations and K-means cluster analyses were adopted to identify a set of probable local wind conditions, which took into account the combined influence of prevailing wind conditions, urban environment and building levels. Through side-by-side comparison of results obtained with and without considering the influence of surrounding buildings, it was found that surrounding buildings lower the wind power available in the vicinity of buildings by 2.5% to 86.8%, increase the angular spread of prevailing winds and adversely affect natural ventilation in residential dwellings. The increase in the mean age of air (MAA) is 0.6 times to 1.5 times. In respect of influence of openings configurations and window types, the conclusion drawn in this study was found to be in agreement with previous studies.