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The article offers news briefs on chemical science as of April 2019. It mentions that the atrium of the new Science Centre (Building 302) at the University of Auckland has been renamed as the Kathleen Curtis Atrium. It mentions that Melissa Cadelis organised the Global Women’s Breakfast at the University of Auckland. It states that the School of Chemical Sciences at the University of Auckland hosted seminars between December 2018 and January 2019.

In case of fire, constructive features of typical atria could favor the spread of smoke. This makes the design of their smoke control and management systems a challenging task. Five full-scale fire experiments in the literature have been analyzed and numerically compared in FDS v6 to explore the influence of the make-up air. However, these fire experiments cover only a limited number of set-ups and conditions, and require further numerical modeling to obtain a deeper understanding of the makeup air influence. Subsequently, 84 simulations with FDS v6 have been carried out, considering different vent areas (air velocity from 0.4 to 5.3 m/s) and configurations, two heat release rates (2.5 and 5 MW), and two pan locations. It is demonstrated that make-up air velocities lower than the prescribed limit of 1 m/s, by the international codes, may induce adverse conditions. Based on our results, we recommended fire engineers to numerically assess the fire scenario with even lower velocity values. The results also show that asymmetric configurations are prone to induce circulation around the flame which can contribute to the formation of longer flames and fire whirls. Thus, this numerical study links two fire types allowing the connection of pool fires to fire whirls, which completely differ in behaviour and smoke filling, for the sake of design of fire safety. [ABSTRACT FROM AUTHOR]

This paper presents full-scale test results and CFD modeling of smoke conditions in atrium fires in the case of symmetric make-up air opening arrangements. The atrium used for the experiments was equipped with a smoke management system capable of exhausting 132 m/s. Thermocouple trees were installed to measure the temperature along the height of the atrium. The N-percentage method was used to determine the smoke interface height from the measured temperature profiles. Make-up air velocities of 1 m/s, 1.5 m/s and 2 m/s were selected to investigate the effect of make-up air velocity on the smoke interface height in the case of 4-side and 2-opposite side openings. The fire size varied from 1 MW to 5 MW to cover the effect of small, medium and large fires. FDS was also used to simulate the atrium fires in order to compare the predictions with the full-scale test results and evaluate the accuracy of the developed correlations. Results show that the limit of 1 m/s is too restrictive in the case of symmetric opening arrangements. A correlation is proposed based on the full-scale test results that can be used to modify the smoke layer height obtained using plume equations so that the effect of make-up air velocity on the smoke layer height is considered. [ABSTRACT FROM AUTHOR]

Fully air-conditioned atria have become increasingly popular in architecture design due to their appealing aesthetic and iconic features to general public. In certain regions of China, climate diversities in winter (freezing-cold) and summer (warm-humid) are huge. Energy consumptions due to air-conditioning of atria in these regions are enormously high. Thus, their corresponding energy managements without compromising the indoor thermal comfort are extremely challenging. The geometric configuration of the atrium has preliminary and significant impacts on the indoor environment and further influences the energy consumption. The impacts of atria’s geometric configuration on indoor thermal condition and energy consumption under highly diversified climate conditions in China are studied in this paper. A fully air-conditioned enclosed atrium with square plane and cross-section is considered in this research. Atria with different section aspect ratio (SAR) and skylight sizes are investigated with a combination of (1) field measurements and computational fluid dynamics (CFD) simulations for temperature distribution and (2) energy simulations for the corresponding energy performance. Case studies for the temperature distribution profile for atria with different SAR and the quantitative correlations between atria’s SAR and its energy performance are presented. Optimum skylight size based on the objective function to minimize the annual energy consumption will also be reported. [ABSTRACT FROM AUTHOR]

This research focuses on daylight assessment in office buildings with different atrium types, proportions and roof aperture designs. The goal is to assess and optimize atrium type and proportions to improve energy efficiency of atrium buildings. This paper investigates daylight metrics in central, attached and semi-enclosed atrium types with different proportions and roof aperture designs, such as monitor and horizontal skylight. Daylight performance is measured based on the proportions of an atrium that are defined by Well Index (WI), used to characterize atria. Climate-Based Daylight Modeling (CBDM) is applied as the assessment strategy with U.S Climate Zone 3 as the climatic setting. Spatial Daylight Autonomy (sDA) and Annual Solar Exposure (ASE) are adopted as the dynamic daylight metrics to compare the results. This study also validates DIVA for Rhino as the simulation tool by comparing daylight results of the computer simulation with the same scale-model. This research applies both scale-model and computer simulation methods to assess daylight and energy performance in atrium buildings based on Well Index. This paper then employs DIVA simulation tool to assess daylight performance based on the Well Index. The results demonstrate that Well Index is a reliable indicator to characterize atrium proportion and confirm that Well Index works with (CBDM). Having assessed the impact of design parameters, such as climate, building thickness, material reflectance, material transmittance, furniture and monitor roof glazing height, the study potentially provides architects with an atrium design database for U.S. Climate Zone 3. This database compares daylight metrics for Well Index of 0.5, 1 and 2 in central, attached and semi-enclosed atrium types using different roof aperture designs. [ABSTRACT FROM AUTHOR]

Atrium is popular element in mercantile buildings, covered shopping mall, airport terminals, and sport arenas. In the event of a fire, these buildings overwhelmingly necessitate the use of a mechanical ventilation system to provide conditions to achieve safe escape route for the building occupants. This manuscript deals with mechanical ventilation system, manual method for the hydraulic calculations and fire design scenarios. This research shows an overview of the Consolidated Model of Fire and Smoke Transport (CFAST) modeling that using to predict ventilation performance and smoke movement in an atrium. CFAST software has many uses in a wide variety of buildings and fire scenarios due to fast, reliable and affective accuracy of output data. In addition CFAST approaches provide a link between outside building weather conditions and fire and smoke development. This paper demonstrated the complete design procedure as an example to fire safety engineer. [ABSTRACT FROM AUTHOR]

The aim of the study is to investigate the office-workers' working conditions in the ordinary and atrium-type buildings. The indoor climate conditions in the cold season in two type of university buildings are presented. The air temperature is on the good level in the both of the buildings. The rooms in the atrium-side of the building A are too tight and the ergonomics is not considered designing the workplaces in the office-rooms. In the auditoriums of the building B it is too noisy (over 70 dB(A)) during the breaks that prevents the rest and the communication between the workers and students. The air humidity is too low in both type of the buildings (< 30% in the cold season, when the rooms are central-heated). It is recommended to moisten the air in the rooms artificially. For the health risk assessment in the workrooms a flexible risk assessment model is used. The risk levels for the indoor climate factors are different in the two type of buildings. [ABSTRACT FROM AUTHOR]

Highlights: [•] Full-scale experimental data of atrium fire tests. [•] Assessment of stair stepping on the smoke layer and temperature field. [•] Validation of CFD numerical model FDS. [•] Numerical study for different area-to-height-squared ratio atria. [•] Good agreement between experiments and numerical simulations, especially far away from the fire source and the centerline. [ABSTRACT FROM AUTHOR]

Abstract: The hot smoke test is often used for commissioning fire smoke management system in atrium buildings, in which liquid fuel is burnt to generate a buoyant plume mixed with artificial tracer smoke to model a fire smoke. The method is usually costly and often causes safety concerns. This paper studied an alternative method of using a cold smoke test, in which pure helium is used to create the buoyant plume. A method was developed to determine the supply rate of pure helium necessary to achieve the same buoyancy effect as that of the corresponding hot smoke test. Computational fluid dynamics (CFD) simulations of the helium smoke tests were conducted and compared to the measured hot smoke tests in a full-scale naturally ventilated atrium and a sub-scale atrium with mechanical ventilation. A new method was added in the CFD model to track the smoke layer height for the simulations of helium smoke based on the concentrations of smoke and helium. It is found that the predicted smoke layer heights based on the mass fractions of the tracer smoke are generally close to the measured ones in the hot smoke tests of different heat release rates. A non-dimensional temperature in the hot smoke test is also found closely related to the dimensionless helium concentrations in the helium smoke test for the atria modeled. Although the consumption of pure helium for a full-scale helium smoke test can be very high, it is promising to use the pure helium smoke test in the lab-scale experiments as the preliminary tests of full-scale and/or lab-scale testing of real fires. [Copyright &y& Elsevier]

Abstract: We consider two horizontally connected compartments with four openings and one compartment on fire; the height of one compartment is fixed, while that of the other varies. A simple small-scale experimental study using air was performed to demonstrate the existence of two stable flow solutions at the same height ratio. Moreover, a macroscopic zonal model is used to theoretically analyze smoke flow direction and smoke mass flow rate. Under different ranges of height ratio, four patterns of smoke flow are identified and studied. One of the solutions is unstable, while the other three solutions are stable, as shown by nonlinear dynamic analysis. Therefore, two stable solutions of smoke flow exist at the same height ratio and ambient conditions when the height ratio is larger than a critical value, and the critical value is shown to be a transcritical bifurcation point. The implications of smoke flow bifurcation on smoke control in an atrium or building with a stairwell are also discussed. [Copyright &y& Elsevier]

Abstract: In this study, the thermal performance of various shapes and geometries of atriums in buildings is examined under various conditions. The goal of the study is to assess the impact of the atrium shape on the building total energy consumption and to identify the most energy-efficient atrium design. The study focuses on four different central atriums types with square and rectangular geometries which have same areas, use, schedule, controls, occupancy, and construction. The atriums exhibit different aspect ratios (length to width). Four cities in United States are selected to represent primary climatic regions of hot-dry, hot-humid, cold, and temperate. Besides, the atrium height, the atrium glazing type, and the glazing ratio are varied throughout the simulation process. Buildings models are constructed using the DOE-2.1E building energy simulation program. The results of this study indicate that in general, the total energy consumption of the narrow, elongated atrium or the rectangular atrium with high ratio of length to width is significantly greater than the square shaped atrium. [Copyright &y& Elsevier]

This review article gives a comprehensive survey of the progress made in computational modeling of the human atria during the last 10 years. Modeling the anatomy has emerged from simple 'peanut'-like structures to very detailed models including atrial wall and fiber direction. Electrophysiological models started with just two cellular models in 1998. Today, five models exist considering e.g. details of intracellular compartments and atrial heterogeneity. On the pathological side, modeling atrial remodeling and fibrotic tissue are the other important aspects. The bridge to data that are measured in the catheter laboratory and on the body surface (ECG) is under construction. Every measurement can be used either for model personalization or for validation. Potential clinical applications are briefly outlined and future research perspectives are suggested. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates the impact of daylight quality on the dynamics of architectural space. Observation of visual daylight aspects is photographically recorded in the main atrium of City Mall (CM), as an architectural space adopting daylight strategy. Classified photos explore the effects of daylight quality aspects on the dynamics of architectural space. Questionnaire is designed in-relation to the classified photos, and is subjectively assessed by a selected group of architects. Statistical analysis of questionnaire findings agrees that daylight quality affects the dynamics of architectural space, and could be an efficient design element for increasing esthetical and emotional aspects of architectural space. Measurements show dynamic daylight variations at different locations in the atrium and sufficient quantities for atrium activities. The study concludes that daylight quality can activate the dynamics of architectural space through adopting comprehensive daylight design to elaborate and advance dynamic visual daylight aspects, while providing required daylight quantities. [Copyright &y& Elsevier]

Abstract: The present paper is focused on the fluid dynamics of the make-up air at the vents in case of an atrium fire, its influence on the fire-induced conditions and the necessity of properly modelling it to obtain a reliable numerical prediction. For this aim, experimental data from two full-scale atrium fire tests conducted in a 20m cubic facility, with venting conditions involving mechanical smoke exhaust and make-up air velocities larger than 1m/s, and with different fire powers, are presented. Subsequent numerical simulations of these tests have been performed with the code Fire Dynamics Simulator v5.5.3. Two different approaches have been followed to simulate the make-up air inlet fluid dynamics, involving one domain which only considers the inside of the building and another which includes part of the outside. In the former simulations, anomalous phenomena around the fire appear, while the inclusion of part of the exterior domain results in completely different fluid dynamics inside the facility, which agrees better with the experimental data. A detailed analysis of the fluid mechanics at the air inlet vents is conducted to explain these discrepancies. Finally, further simulations are performed varying the make-up area and the exterior extension to assess the appearance of the aforementioned phenomenon. [Copyright &y& Elsevier]

This study investigated the impact of well geometry and surface reflectance on vertical daylight factors on the walls of rectangular atria under a CIE standard overcast sky. The vertical daylight factors predicted using the modelling software Radiance were validated by artificial sky scale model measurements. More simulated data of vertical daylight factors for a very wide range of rectangular atrium geometries and surface reflectances are presented. From the results the variations of the vertical daylight factor on the walls of rectangular atria were assessed and some empirical functions were derived. Initial guidelines for supporting design are presented. [ABSTRACT FROM AUTHOR]

This study investigated the impact of well geometry and surface reflectance on the vertical daylight factors of walls in atria with square plan forms under a CIE standard overcast sky. Artificial sky scale model measurements were used to validate predicted values of vertical daylight factors using the software package Radiance. More simulated vertical daylight factors data for a much wider range of square atrium geometries and surface reflectances were then produced. From the results the variations of the vertical daylight factor on the walls of square atria were assessed and explained and some empirical functions derived. Some guidelines for supporting design are presented. [ABSTRACT FROM AUTHOR]

Abstract: Hybrid ventilation is the building ventilation system that integrates natural and mechanical ventilation components to create a high efficiency and healthy ventilation system for a building. Here, hybrid ventilation is used to control fire-induced smoke in a huge transit terminal subway station. Four different grid systems are compared, and the sensitivities of these gird systems are analyzed. The effect of hybrid ventilation on carbon monoxide (CO) concentration reduction and its suppression effect on horizontal dispersion of smoke are also analyzed. Heat release rate, smoke temperature in the vertical direction, smoke layer height and CO concentration are validated with previous experimental data, and good agreement is achieved. Preliminary results show that the average CO concentration in the hall decreases significantly with increasing roof window size and air change rate (ACH). However, little CO concentration difference in the atrium can be observed. Comparing with the conventional mechanical ventilation, hybrid ventilation can inhibit the dispersion of smoke more effectively. The CO concentration in the subway station in the horizontal direction is significantly lower than that with conventional mechanical ventilation. It suggests hybrid ventilation by setting roof window in the ceiling of the atrium with size of 3m×3m or larger can be an effective method to exhaust fire-induced smoke. [Copyright &y& Elsevier]

Abstract: Similarities of a reduced-scale building model using air as the working fluid for buoyancy-driven natural ventilation have been analyzed and experiments were carried out using the scaled model for a common natural ventilation building, which has open office floor plans connected to a central atrium. Both open and closed cases have been investigated for the stack vents, located at the top of the atrium. Inputs for the scaled building model were taken from results measured in the prototype building by the authors. The parameters of the scaled building model''s experiments thus were used as inputs into a computational fluid dynamics (CFD) simulation model to compare predicted and measured airflow patterns, temperatures and velocity distributions in the scaled building model. [Copyright &y& Elsevier]

This study investigated the impact of well geometry on vertical sky components in atria with square and rectangular forms under a CIE standard overcast sky. By comparing scale model measurements and analytical theory the vertical sky components, calculated using Radiance, were validated. More simulated data of vertical sky components for a very wide range of atrium geometries are given. From the results the attenuation of the vertical sky component on the wall of a square atrium is explained and some empirical functions are derived. In addition, the results from atrium models with rectangular floor plans show the relationships between the vertical sky component and the plan aspect ratio. Some guidelines for design are presented. [ABSTRACT FROM AUTHOR]

Abstract: In recent years, highly glazed atria are popular because of their architectural aesthetics and advantage of introducing daylight into inside. However, cooling load estimation of such atrium buildings is difficult due to complex thermal phenomena that occur in the atrium space. The study aims to find out a simplified method of estimating cooling loads through simulations for various types of atria in hot and humid regions. Atrium buildings are divided into different types. For every type of atrium buildings, both CFD and energy models are developed. A standard method versus the simplified one is proposed to simulate cooling load of atria in EnergyPlus based on different room air temperature patterns as a result from CFD simulation. It incorporates CFD results as input into non-dimensional height room air models in EnergyPlus, and the simulation results are defined as a baseline model in order to compare with the results from the simplified method for every category of atrium buildings. In order to further validate the simplified method an actual atrium office building is tested on site in a typical summer day and measured results are compared with simulation results using the simplified methods. Finally, appropriate methods of simulating different types of atrium buildings are proposed. [ABSTRACT FROM AUTHOR]

This paper presents an investigation on the scenarios of the natural smoke filling times in an atrium due to a located floor fire. Based on the Heskestad's correlation, the heat release rate and the effective height of the fire source were transformed into an equation associated with the diameter and perimeter of the fire source. Neglecting the thermal effect for heat release due to relatively small temperature rise in the atrium and applying the assumption of mass conservation, the height of smoke layer interface can be derived. In this study, the various plume models such as McCaffrey's correlation, Zukoski's correlation, Thomas's correlation and NFPA 92B's correlation are considered with both steady fire and unsteady fire situations. The comparisons between the theoretical results and the experimental data were also made and discussed. [ABSTRACT FROM AUTHOR]

Abstract: In winter, natural ventilation can be achieved either through mixing ventilation or upward displacement ventilation (P.F. Linden, The fluid mechanics of natural ventilation, Annual Review of Fluid Mechanics 31 (1999) pp. 201–238). We show there is a significant energy saving possible by using mixing ventilation, in the case that the internal heat gains are significant, and illustrate these savings using an idealized model, which predicts that with internal heat gains of order 0.1kW per person, mixing ventilation uses of a fraction of order 0.2–0.4 of the heat load of displacement ventilation assuming a well-insulated building. We then describe a strategy for such mixing natural ventilation in an atrium style building in which the rooms surrounding the atrium are able to vent directly to the exterior and also through the atrium to the exterior. The results are motivated by the desire to reduce the energy burden in large public buildings such as hospitals, schools or office buildings centred on atria. We illustrate a strategy for the natural mixing ventilation in order that the rooms surrounding the atrium receive both pre-heated but also sufficiently fresh air, while the central atrium zone remains warm. We test the principles with some laboratory experiments in which a model air chamber is ventilated using both mixing and displacement ventilation, and compare the energy loads in each case. We conclude with a discussion of the potential applications of the approach within the context of open plan atria type office buildings. [Copyright &y& Elsevier]

Abstract: An extended Gebhart–Block model for large space buildings is proposed in this paper, which is used to predict the vertical temperature distribution of hybrid ventilation. Natural ventilation coupled with air-conditioning is described with a mathematical model. The indoor thermal environment formed by the air-conditioning and the natural ventilation can also be conducted for the potential analysis and optimal use of the natural ventilation. Experiments were carried out in an atrium building in Shanghai Research Institute of Building Sciences. This paper describes aforementioned model, and it is found that the calculation results implying this model agree well with the measurement data. [Copyright &y& Elsevier]

This paper investigates the main characteristics of the atrium and their influence on the daylight conditions in the adjoining space and on the atrium floor. The shape of the atrium and its orientation to the sun, the transmittance of the roof, the reflectivities of the atrium surfaces and the glazed areas are important parameters in the daylighting design of atrium buildings. Several atrium cases, characterized by a different Well Index, are analysed and a simplified methodology used, to predict daylight factor on the atrium floor and in the adjacent rooms, developed through computer simulation using Radiance as a tool. [Copyright &y& Elsevier]

This paper presents the field-measured energy performance of two common types of daylight-linked lighting control systems, continuous dimming and automatic on/off installed in two existing large atrium spaces located in Canada. The daylighting performance was evaluated based on the daylight contribution to the indoor illuminance and the amount of electrical lighting displaced by daylighting via the daylight-linked lighting control systems. Measured daylighting contribution to the space indicates that significant lighting energy savings can be achieved in atrium spaces if the daylight-linked lighting control system is appropriately selected, installed and commissioned throughout its existence. Results extrapolated from measurements collected during summer and winter indicate that as installed, the continuous dimming lighting control system provides 46% annual savings in electrical lighting consumption, while the automatic on/off saves between 11and 17% in lighting energy. These savings account for 68% of the lighting energy consumed during main occupancy for the continuous dimming system, and 31.5% for the automatic on/off. Operation irregularities such as a reduced dimming linearity and an incorrect adjustment of the phases of the dimming control system, as well as the inadequate location of the photocell controlling the automatic on/off lighting system, the improper maintenance of the skylight during winter and the oversizing of the lighting system reduced the energy efficiency of the lighting control systems by 30–65%. [Copyright &y& Elsevier]

It is often complex and difficult to predict the daylighting of an atrium building. The atrium is usually expected not only to be an attractively daylit space in its own right, but also to deliver light to adjoining spaces. Most of the light reaching these spaces will have been reflected within the atrium. This paper outlines current guidance on daylighting design for atria and reviews published techniques to calculate daylight within them, including a methodology to predict daylight factors within atria and the surrounding spaces. [ABSTRACT FROM AUTHOR]

Presents information on a wind tunnel study which investigated the airflow through courtyard and atrium building models located within an urban setting and exposed to an urban atmospheric boundary layer. Courtyard and atrium roof ventilation models and strategies; Ratio of sheltered to isolated average flow for the courtyard and atrium models; Conclusion.

Several myocardial lesions can be induced by thoracic blunt trauma. It varies from myocardial lesions to heart rupture. We report a case of right atrial rupture due to unusual blunt trauma: a hoof kick. We describe a successful management of this case. We suggest that a diagnosis of cardiac chamber rupture should be considered in all cases of blunt thoracic trauma. [Copyright &y& Elsevier]

Experimental studies on natural smoke filling during an atrium fire were carried out in a new full-scale burning facility: the PolyU/USTC Atrium, at Hefei, Anhui, China. The internal dimension of the atrium is 22.4 m long, 11.9 m wide, and 27 m high. A diesel pool fire of 1.2 m diameter and heat release rate up to 654 kW was located at the center of the atrium floor. All vents of the atrium were closed, leaving just a vertical gap of width 1.65 m and height 0.2 m for supplying fresh air. Five hot smoke tests were carried out. Vertical temperature distributions and descending time of the smoke layer were measured. Results on the smoke-filling process compiled from the tests were compared with the USTC/PolyU model, a simple mathematical model developed from a plume equation appearing in the literature. Comparison was also made with the smoke-filling equation appearing in the literature. [ABSTRACT FROM AUTHOR]

Due to the multiple benefits on energy, well-being, comfort, and the economy, the utilization of daylight remains an imperative topic of architectural design. With the remarkable ability of drawing and increasing daylight deep into the core of buildings, atriums with a large proportion of glazing have become one of the most preferred design forms. The concomitant and unexpected visual discomfort in modern buildings, however, has drawn increasing concerns. Therefore, this study investigated the relation between glazing proportion and daylight performance, as well as the impact of building height and atrium types on daylight performance in atrium buildings by using an annual dynamic simulation method and metrics. It was found that extending glazing proportion had prominent effectiveness in the enhancement of daylighting; building height had a negative influence; round and square types of buildings performed much better than rectangular ones. Moreover, to inform a practical design, we analyzed the link between increasing daylight and visual comfort from the perspective of balancing them, and then proposed a design guide for atrium roof-glazing sizing. [ABSTRACT FROM AUTHOR]