Dome Building Research Articles

Parametric control of multiple blinds to enhance daylighting performance in the dome building: Case study of a mosque building in Saudi Arabia

Clerestory windows encircling the dome are a common feature in mosque architecture. They serve the purpose of allowing daylight to penetrate the spacious interior from all directions through smaller windows compared to side-lit windows. However, maintaining the required uniform daylighting coverage throughout the day in buildings with different directions remains a challenge. The integration of advanced daylighting systems with dome geometry, coupled with parametric control, can significantly enhance daylighting performance. In this research, a novel approach and simplified integrated method for parametrically controlling a multiple blinds system with incremental slat angle in a mosque dome's drum are developed, whereby the blinds in each direction respond independently and parametrically to the sun's movement. Parametrically controlled blinds are installed on the windows around the mosque’s dome to maximize the utilization of daylight while preventing direct penetration of solar radiation. Then, the daylighting performance of parametrically controlled multiple blinds was compared to that of conventional blinds and unshaded windows in a typical Mosque in Saudi Arabia during the noon prayer time. The study found that the parametrically controlled blinds can dramatically enhance the daylight coverage inside the mosque from around 38% to 88% for an illuminance range of 150–500 lx, while protecting users from direct sunlight. Promisingly, the system revealed that it can protect worshippers from direct sunlight, minimize potential glare and provide visual comfort.

Numerical thermomechanical modelling of lava dome growth during the 2007–2009 dome-building eruption at Volcán de Colima

SUMMARY Lava domes form during effusive eruptions due to an extrusion of highly viscous magmas from volcanic vents. In this paper we present a numerical study of the lava dome growth at Volcán de Colima, Mexico during 2007–2009. The mathematical model treats the lava dome extrusion dynamics as a thermomechanical problem. The equations of motion, continuity and heat transfer are solved with the relevant boundary and initial conditions in the assumption that magma viscosity depends on the volume fraction of crystals and temperature. We perform several sets of numerical experiments to analyse the internal structure of the lava dome (i.e. the distributions of the temperature, crystal content, viscosity and velocity) depending on various heat sources and thermal boundary conditions. Although the lava dome growth at Volcán de Colima during short (a few months) dome-building episodes can be explained by an isothermal model of lava extrusion with the viscosity depending on the volume fraction of crystals, we show here that cooling plays a significant role during long (up to several years) episodes of dome building. A carapace develops as a response to a convective cooling at the lava dome–air interface. The carapace becomes thicker if the radiative heat loss at the interface is also considered. The thick carapace influences the lava dome dynamics preventing its lateral advancement. The release of the latent heat of crystallization leads to an increase of the temperatures in the lava dome interior and to a relative flattening of the dome. Meanwhile, the heat source due to viscous dissipation inside the lava dome is negligible, and it does not influence the lava dome growth. The developed thermomechanical model of the lava dome dynamics at Volcán de Colima can be used elsewhere to analyse effusive eruptions, dome morphology and carapace evolution including its failure potentially leading to pyroclastic flow hazards.

Eruption dynamics of Anak Krakatau volcano (Indonesia) estimated using photogrammetric methods

Analyzing video data from an uncrewed aerial vehicle (UAV) of two short-lived dome building events at Anak Krakatau volcano (Indonesia), we determine vertical and horizontal movements of the dome surface prior to explosions, as well as initial eruption velocities and mass eruption rates via automated feature tracking and other photogrammetric methods. Initial eruption velocities and mass eruption rates are estimated as a proxy for eruptive strength. Eruptive strength is found to correlate with deformation magnitude, i.e., larger pre-explosion surface displacements are followed by both higher initial eruption velocities and mass fluxes. In accord with other studies, our observations can be explained by an overpressure underneath the dome’s surface. We assume that the dome seals the underlying vent efficiently, meaning that pre-explosion pressure build-up controls both deformation magnitude and eruptive strength. We support this assumption by a simple numerical model indicating that pre-explosion pressure increases between 8 and 16 MPa. The model further reveals that the two events vary significantly with respect to the importance of lateral visco-elastic flow for pressurization and deformation. The video sequences also show considerable variations in the gas release and associated deformation characteristics. Both constant and accelerating deformation is observed. Our case study demonstrates that photogrammetric methods are suitable to provide quantitative constraints on both effusive and explosive activity. Future work can build on our or similar approaches to develop automated monitoring strategies that would enable the observation and analysis of volcanic activity in near real time during a volcanic crisis.

A reliable numerical model for assessing the thermal behavior of a dome building

The thermal assessment of a building is very important for the selection of heating installations, ensuring the well-being of its users and a sustainable building lifecycle. The purpose of the research was to recreate numerically the thermal behavior of a building in time. Numerical analyses and in-situ tests were carried out. The temperature of the envelope surface of a dome-shaped building and climatic parameters were measured in real conditions. The results were used to verification of the numerical model of the building. The object was described by coupled equations of heat and mass transfer, which were solved by the finite volume method. The influence of time discretisation and the physical properties of the envelope materials (ρ, c, λ, ε, α) on the temperature of the external envelope surface were determined. It was demonstrated that the absorption coefficient of the external layer material was influential on the results. Based on the results of the numerical analyses and in-situ test was to ascertain the reliability of numerically recreate of the building thermal behavior. Method of creating reliable numerical model of a dome building, with application of general data from a typical meteorological year in order to assess its thermal behavior was determined.

Transition from passive to pre-extrusion degassing of ascending andesitic magma before the lava dome-building eruption as derived from the seismic signals and tilt changes: Volcán de Colima, México, August–September 2004

Volcanoes emit volcanic gas during various types of activity. In the case of andesitic and dacitic volcanoes the high viscosity of silicic magma inhibits the release of volatiles. This increases the possibility that gas escape will occur explosively. The explosive emission of volatile constituents, presented in magmas, generates the seismic signals which may give information about the process of degassing at different stages of eruption. Transition between the eruptive episodes of lava dome-building at andesitic volcanoes represents the transition from passive degassing of the final stage of one episode to pre-extrusion degassing of the next episode. In this article we use the seismic parameters of volcanic explosions, volcanic tremor and micro-explosions, recorded at Volcán de Colima during August–September 2004, to describe the process of transition from passive to pre-extrusion degassing from episode 2 (May 2001–September 2004) to episode 3 (30 September 2004–January 2007). Variations in the tilt changes allowed us to identify three periods in development of this transition: period of passive degassing at the final stage of episode 2 (until 6 September) and two periods of pre-extrusive degassing at the initial stage of episode 3 defined by processes of inflation and deflation of volcanic structure from 6 to 30 September. Intensity of degassing of magma, expressed in the energy of volcanic explosions, decreased during transition from passive to pre-extrusive stages. During pre-extrusion periods of inflation and deflation of volcanic structure the depths of explosive events became shallower. Period of deflation was characterized also by a dominance of degassing processes occurring within the permeable cap of ascending magma and generating volcanic tremors and swarms of micro-earthquakes. Comparison of degassing of magma during pre-extrusive period and co-extrusive and post-extrusive periods showed the similarity in intensity of degassing of magma during the pre-extrusive and co-extrusive periods but a sharp increase in degassing intensity during the post-extrusive period of lava dome destruction with large explosions. It was shown also minor intensity of degassing processes just preceding the beginning of the lava dome building comparing with intensity of degassing processes just preceding the beginning of the lava dome destruction with great explosions.

Overview, chronology, and impacts of the 2016–2017 eruption of Bogoslof volcano, Alaska

The 2016–2017 eruption of Bogoslof volcano, a back-arc shallow submarine volcano in Alaska’s Aleutian arc, began in December 2016 and included 70 explosive events and at least two episodes of subaerial dome building. Because the volcano had no local monitoring stations during the eruption, a combination of distant seismic stations, regional infrasound sensors, lightning detection, a variety of satellite data and observer reports, and a field visit in 2018, were used to recreate the events that occurred during the nine-month eruption. Following precursory seismicity that started in September 2016, the eruption began in December 2016 with a series of explosive events that persisted through mid-March 2017. After a 6-week hiatus, activity resumed on May 17 and lasted through the end of August 2017 and consisted of additional explosions and two short-lived subaerial lava domes that formed in June and August. For most of the eruption, Bogoslof’s vent was submerged in shallow seawater, though during several of the longer events a subaerial edifice grew, and the vent migrated above sea level resulting in more ash-rich volcanic clouds. Eruptive products, geophysical signals, and eruptive style are all broadly consistent with vulcanian activity where slow magma ascent led to repetitive dome or plug formation, overpressurization in the upper conduit, and sudden release during short-lived explosions. Infiltration of seawater may have prohibited large domes from forming especially in the first half of the eruption when explosions were closely spaced in time. The largest four explosions in the sequence occurred after inter-event times of 10 days or more. Three events produced ashfall on nearby communities and mariners east and south of Bogoslof and the eruption resulted in dozens of flight cancelations and flight diversions around the volcano and its ash clouds.

The 3.6 Metre Devasthal Optical Telescope:From Inception to Realization

India's largest size 3.6 meter Devashal optical telescope (DOT) was commissioned in the year 2016, though the idea of building it germinated way back in the year 1976. This article provides research accounts as well as glimpses of its nearly four decades of journey. After a decade of site surveys, location of Devasthal in central Himalyan region of Kumaon was identified. Thereafter, a detailed site characterization was conducted and project approvals were obtained. The telescope is designed to be a technologically advanced optical astronomy instrument. It has been demonstrated to resolve a binary star having angular separation of 0.4 arc-sec. After the technical activation of the telescope on March 30, 2016, it has been in regular use for testing various back-end instruments as well as for optical and near-infrared observations of celestial objects. Back-end instruments used for these observations are 4KX4K CCD imager, Faint object imager cum spectrograph and TIFR near-infrared camera-II. A few published science results based on the observations taken with the telescope are also presented. Furthermore, the routine observations find that for a good fraction of observing time the telescope provides sky images of sub-arc-second resolution at optical and near-infrared wavelengths. This indicates that the extreme care taken in the design and construction of the telescope dome building has been rewarding since the as-built thermal mass contributes minimally so as not to degrade the natural atmospheric seeing measured at Devasthal about two decades ago during 1997-1999 using differential image motion monitor. The overall on-site performance of the telescope is found to be excellent and at par with the performance of other similar telescopes located over the globe.

Deformations and Morphology Changes Associated with the 2016–2017 Eruption Sequence at Bezymianny Volcano, Kamchatka

Lava domes grow by extrusions and intrusions of viscous magma often initiating from a central volcanic vent, and they are frequently defining the source region of hazardous explosive eruptions and pyroclastic density currents. Thus, close monitoring of dome building processes is crucial, but often limited to low data resolution, hazardous access, and poor visibility. Here, we investigated the 2016–2017 eruptive sequence of the dome building Bezymianny volcano, Kamchatka, with spot-mode TerraSAR-X acquisitions, and complement the analysis with webcam imagery and seismic data. Our results reveal clear morphometric changes preceding eruptions that are associated with intrusions and extrusions. Pixel offset measurements show >7 months of precursory plug extrusion, being locally defined and exceeding 30 m of deformation, chiefly without detected seismicity. After a short explosion, three months of lava dome evolution were characterised by extrusions and intrusion. Our data suggest that the growth mechanisms were significantly governed by magma supply rate and shallow upper conduit solidification that deflected magmatic intrusions into the uppermost parts of the dome. The integrated approach contributes significantly to a better understanding of precursory activity and complex growth interactions at dome building volcanoes, and shows that intrusive and extrusive growth is acting in chorus at Bezymianny volcano.

Episodes of dormancy and eruption of the Late Pleistocene Ciomadul volcanic complex (Eastern Carpathians, Romania) constrained by zircon geochronology

Ciomadul is the youngest volcanic system in the Carpathian-Pannonian Region recording eruptive activity from ca. 1 Ma to 30 ka. Based on combined zircon U-Th and (U-Th)/He geochronology, Ciomadul volcanism is divided into two main eruptive periods: Old Ciomadul (1 Ma – 300 ka; OCEP) and Young Ciomadul Eruptive Period (160–30 ka; YCEP). OCEP activity comprises Eruptive Epochs 1–3, whereas new ages for eight lava domes and four pyroclastic units belonging to the YCEP lead to its further subdivision into two eruptive epochs: Eruptive Epochs 4 and 5. The extrusion of most of the lava domes occurred between 160 and 90 ka (Eruptive Epoch 4) during three eruptive episodes at ca. 155 ka, 135 ka and 95 ka (Eruptive Episodes 4/1, 4/2 and 4/3, respectively) along a NE-SW lineament, which is perpendicular to the regional NW-SE trend of the Călimani-Gurghiu-Harghita volcanic chain. Eruptive Epoch 5 occurred after a ca. 40 kyr of quiescence at ca. 55–30 ka, and is mainly characterized by explosive eruptions with a minor lava dome building activity. All of the dated pyroclastic outcrops, together with the lava dome of Piscul Pietros, belong to the older Eruptive Episode 5/1, with an eruption age of 55–45 ka. The eruption centers of Eruptive Epoch 5 are located at the junction of the conjugated NW-SE and NE-SW lineaments defined by the older eruptive centers. The whole-rock geochemistry of all studied samples is fairly homogeneous (SiO2 = 63–69 wt%, K2O = 3–4 wt%). It also overlaps with the composition of the lava domes of the Old Ciomadul Eruptive Period, implying a monotonous geochemical characteristic for the past 1 Myr. The eruption rates for the Ciomadul volcanism were determined based on the erupted lava dome volume calculations, supplemented with the eruption ages. The activity peaked during the Eruptive Epoch 4 (160–90 ka), having an eruption rate of 0.1 km3/kyr. In comparison, these values are 0.05 km3/kyr for the YCEP (160–30 ka) and 0.01 km3/kyr for the overall Ciomadul volcanism (1 Ma–30 ka). Based on the geochemical characteristics, the quiescence periods and the lifetime of the complex, as well as the relatively small amount of erupted material, this volcanic system can be placed in a subduction-related post-collisional geodynamic setting, which shows strong chemical similarities to continental arc volcanism. The commonly found long repose times between the active phases suggest that the nature of a volcano cannot be understood solely based on the elapsed time since the last eruption. Instead, comprehensive geochronology, coupled with the understanding of the magma storage behavior could be a base of hazard assessment for volcanic fields, where the last eruptions occurred several 10's of thousand years ago and therefore they are not considered as potentially active.

Buildings and constructions on the base of timber for the Arctic regions

Economic efficiency of development of high-latitude territories directly depends on the construction technologies applied here. Traditional materials such as reinforced concrete and steel cause unacceptably high resource consumption throughout the entire technological chain of construction production in the Northern regions, and the mechanical transfer of construction technologies to high-latitude construction are ineffective. Analysis of environmental effects on buildings and structures has shown that the most effective for the Extreme North is the dome shape, namely: the building of the lenticular shape; dome building; the building in the form of a sphere; in the form of a cone formed by rotating the Reuleaux triangle around the vertical axis of symmetry; the building of tetrahedron type, and various shapes formed by the combination of buildings of dome shapes. The rationality of constructions made of wood and wood materials is emphasized, which determines the necessity of creating an industry of glued elements. It has been widely used in high-latitude construction and has proved to be the best in terms of frost resistance, low resistance to corrosion from blizzards, high specific strength and low thermal conductivity for a long time.

Scientific potential of the Indo-Belgian 3.6-m DOT in the field of Galactic Astronomy

India and Belgium have jointly established two 4-meter class optical telescopes at Devasthal located in Nainital, India. After successful installation of the 3.6-m modern new technology Devasthal Optical Telescope (DOT) in 2015, it was technically activated by premiers of both countries from Brussels on March 30, 2016. Since then, the 3.6-m DOT has been used for both optical and near-Infrared (NIR) observations for a number of research proposals. The best angular resolution achieved is 0″.4 indicating that the optics of the 3.6-m DOT is good and capable of providing images of celestial bodies with sub-arc-second resolution. The observations provide proof that the care taken in the construction of the telescope dome building has paid a rich dividend as their thermal mass is so low that it has not degraded the natural atmospheric seeing at Devasthal measured about two decades ago during 1997 to 1999 using differential image motion monitor. A few preliminary scientific results obtained from recent observations are presented along with performance and global potential of the 3.6-m DOT in the field of galactic astronomy. The 3.6-m DOT is capable of providing internationally competitive science once high resolution spectrograph and other planned modern back-end instruments become operational. Geographical location of the observatory has global importance for time domain and multi-wavelength astrophysical studies.

Climatic analysis of ventilation and thermal performance of a dome building with roof vent

This paper presents a climatic analysis of a naturally ventilated geodesic-type dome building situated in a hot climate. A comprehensive review of the literature was conducted to provide an overview of previous related research on dome-type-roof buildings. The two-floor geodesic dome building assessed in this study was based on a 3V icosahedron type and had a roof vent for natural ventilation. The airflow and temperature distributions inside the building were simulated using computational fluid dynamics modelling with the standard k–ε turbulence model. The computational modelling was verified using sensitivity analysis and flux balance analysis. Validation was carried out by using a similar dome-shaped building model from the literature. The atmospheric boundary layer flow was simulated in the computational domain for a more realistic prediction of wind conditions. The thermal comfort level was assessed using the predicted mean vote method. The results showed that the integration of the roof vents was advantageous and could reduce the indoor temperature and introduce fresh air, particularly during winter. The results also revealed that natural ventilation using roof vents could not satisfy the thermal requirements during summer periods, and potential cooling solutions that could be integrated into the system are discussed.

Assessment of Dome Building Damage and Repair Method

The paper deals with the assessment of the damage of a concrete dome type of structure and the method of repairment. Due to own weight of the dome, the concrete portion of the dome near bottom rim is in tension and the steel reinforcement was not sufficiently provided, causing cracks at bottom and leakage at top of dome. UPV tests, profometer tests and core drilling were carried out to observe the condition of existing dome. Testing results were used as bases for constructing repairment method, epoxy grout, epoxy mortar and the use of carbon fibre reinforced plastic (CFRP).

A comparison of the forces on dome and prism for straight and tornadic wind using CFD model

Tornadoes are vertical swirling air formed because of the existence of layers of air with contrasting features of temperature, wind flow, moisture, and density. Tornadoes induce completely different wind forces than a straight-line (SL) wind. A suitably designed building for an SL wind may fail when exposed to a tornado-wind of the same wind speed. It is necessary to design buildings that are more resistant to tornadoes. In tornado-damaged areas, dome buildings seem to have less damage. As a dome structure is naturally wind resistant, domes have been used in back yards, as single family homes, as in-law quarters, man caves, game rooms, storm shelters, etc. However, little attention has been paid to the tornadic wind interactions with dome buildings. In this work, the tornado forces on a dome are computed using Computational Fluid Dynamics (CFD) for tornadic and SL wind. Then, the interaction of a tornado with a dome and a prism building are compared and analyzed. This work describes the results of the tornado wind effect on dome and prism buildings. The conclusions drawn from this study are illustrated in visualizations. The tornado force coefficients on a dome building are larger than SL wind forces, about 120% more in x- and y-directions and 280% more in z-direction. The tornado maximum pressure coefficients are also higher than SL wind by 150%. The tornado force coefficients on the prism are larger than the forces on the dome, about 100% more in x- and y-directions, and about 180% more in z-direction. The tornado maximum pressure coefficients on prism also are greater those on dome by 150% more. Hence, a dome building has less tornadic load than a prism because of its aerodynamic shape.

Investigating the Apparent Seismic Diffusivity of Near-Receiver Geology at Mount St. Helens Volcano, USA

We present an expanded approach of the diffusive approximation to map strongly scattering geological structures in volcanic environments using seismic coda intensities and a diffusive approximation. Seismic data from a remarkably consistent hydrothermal source of Long-Period (LP) earthquakes, that was active during the late 2004 portion of the 2004–2008 dome building eruption of Mount St. Helens Volcano, are used to obtain coefficient values for diffusion and attenuation, and describe the rate at which seismic energy radiates into the surrounding medium. The results are then spatially plotted as a function of near-receiver geology to generate maps of near-surface geological and geophysical features. They indicate that the diffusion coefficient is a marker of the near-receiver geology, while the attenuation coefficients are sensitive to deeper volcanic structures. As previously observed by other studies, two main scattering regimes affect the coda envelopes: a diffusive, multiple-scattering regime close to the volcanic edifice and a much weaker, single-to-multiple scattering regime at higher source-receiver offsets. Within the diffusive, multiple-scattering regime, the spatial variations of the diffusion coefficient are sufficiently robust to show the features of laterally-extended, coherent, shallow geological structures.

Evaluating links between deformation, topography and surface temperature at volcanic domes: Results from a multi-sensor study at Volcán de Colima, Mexico

Dome building activity is common at many volcanoes and due to the gravitational instability, a dome represents one of the most hazardous volcanic phenomena. Shallow volcanic processes as well as rheological and structural changes of the dome affecting the fluid transport have been linked to transitions in eruptive activity. Also, hydrothermal alteration may affect the structural integrity of the dome, increasing the potential for collapse. However, mapping the deformation and details of fluid escape at the summit of steep sloped volcanoes and integrating these with other types of data is challenging due to difficult access and poor coverage. Here we present for the first time the near-vertical and near-horizontal surface deformation field of a quiescent summit dome and the relationships with degassing and topographic patterns. Our results are derived from high resolution satellite radar interferometry (InSAR) time series based on a year of TerraSAR-X SpotLight acquisitions and Structure from Motion (SfM) processing of overflight infrared data at Volcán de Colima, Mexico. The identified deformation is dominated by localized heterogeneous subsidence of the summit dome exceeding rates of 15 cm/yr, and strongly decreasing over the year 2012, up to the renewal of explosive and extrusive activity in early 2013. We tentatively attribute the deformation to the degassing, cooling and contraction of the dome and shallow conduit material. We also find that the results strongly differ depending on the chosen InSAR time series method, which potentially overprints the true physical complexities of small scale, shallow deformation processes. The combined interpretation of the deformation and infrared data reveals a complex spatial relationship between the degassing pathways and the deformation. While we observe no deformation across the crater rim fumaroles, discontinuities in the deformation field are more commonly observed around the dome rim fumaroles and occasionally on the dome upper surface. We propose that the deformation pattern is also linked to processes controlling the fumarole formation and distribution (topography, permeability and volcanic activity), and the lack of direct relationships may be explained by how the influence of these processes varies across the volcanic summit. The presented work provides a new approach for safely monitoring the activity and stability of internal dome structures, as well as for constraining and validating models of dome degassing pathways and densification processes.

Separating volcanic deformation and atmospheric signals at Mount St. Helens using Persistent Scatterer InSAR

Over the past two decades, GPS and leveling surveys have recorded cycles of inflation and deflation associated with dome building eruptions at Mount St. Helens. Due to spatial and temporal limitations of the data, it remains unknown whether any deformation occurred prior to the most recent eruption of 2004, information which could help anticipate future eruptions. Interferometric Synthetic Aperture Radar (InSAR), which boasts fine spatial resolution over large areas, has the potential to resolve pre-eruptive deformation that may have occurred, but eluded detection by campaign GPS surveys because it was localized to the edifice or crater. Traditional InSAR methods are challenging to apply in the Cascades volcanic arc because of a combination of environmental factors, and past attempts to observe deformation at Mount St. Helens were unable to make reliable observations in the crater or on much of the edifice.In this study, Persistent Scatterer InSAR, known to mitigate issues of decorrelation caused by environmental factors, is applied to four SAR data sets in an attempt to resolve localized sources of deformation on the volcano between 1995 and 2010. Many interferograms are strongly influenced by phase delay from atmospheric water vapor and require correction, evidenced by a correlation between phase and topography. To assess the bias imposed by the atmosphere, we perform sensitivity tests on a suite of atmospheric correction techniques, including several that rely on the correlation of phase delay to elevation, and explore approaches that directly estimate phase delay using the ERA-Interim and NARR climate reanalysis data sets. We find that different correction methods produce velocities on the edifice of Mount St. Helens that differ by up to 1cm/yr due to variability in how atmospheric artifacts are treated in individual interferograms. Additionally, simple phase-based techniques run the risk of minimizing any surface deformation signals that may themselves be correlated with elevation. The atmospherically corrected PS InSAR results for data sets overlapping in time are inconsistent with one another, and do not provide conclusive evidence for any pre-eruptive deformation at a broad scale or localized to the crater or edifice leading up to the 2004 eruption. However, we cannot rule out the possibility of deformation less than ~1cm/yr, or discern whether deformation rates increased in the months preceding the eruption. The results do significantly improve the spatial density of observations and our ability to resolve or rule out models for a potential deformation source for the pre-eruptive period.

The Anniversary of a Massacre and the Death of a Monarch

As part of this year's anniversary of the October 6, 1976, massacre at Thammasat University, an outdoor exhibit of photographs of the violence and the three preceding years of student and other social movements was displayed upon the very soccer field in the center of campus where students were beaten, shot, lynched, and murdered forty years prior. Several of the photographs were printed on large sheets of acrylic and positioned such that the images of the buildings in the photographs were aligned with the actual buildings, which remain largely unchanged. The most striking of these was a photograph of hundreds of students stripped to the waist who were lying face down on the soccer field prior to being arrested and taken away. At the edge of the image was the top of the university's iconic dome building, which lined up with the existing building. The organizers explained that their intention was “to reflect a perspective on the past through the eyes of people in the present in order to show the cruelty of humans to one another.” The proximity generated by the image was underlined by the fact that the fortieth anniversary of the massacre and coup in 1976 that led to twelve years of dictatorship was taking place under yet another dictatorship, that of a military junta calling itself the National Council for Peace and Order (NCPO), which seized power on May 22, 2014, in the twelfth coup since the end of the absolute monarchy on June 24, 1932. Suchada Chakphisut, founding editor ofSarakadeemagazine and Thai Civil Rights and Investigative Journalism, who was a first-year Thammasat student during the massacre, began her autobiographical account of the day, written for the anniversary this year, by writing: “We meet every year when 6 October comes around, and with it an inexplicable sadness always takes hold of my psyche. It has grown even more devastating since the 22 May 2014 coup, in which we must face the news of the arrest and detention of activists and those who oppose dictatorship.” This was not a commemorationafterdictatorship such as those of the same era held in Argentina or Chile during recent years of democratization, but memories of dictatorship in situ.

Computational Analysis of Natural Ventilation Flows in Geodesic Dome Building in Hot Climates

For centuries, dome roofs were used in traditional houses in hot regions such as the Middle East and Mediterranean basin due to its thermal advantages, structural benefits and availability of construction materials. This article presents the computational modelling of the wind- and buoyancy-induced ventilation in a geodesic dome building in a hot climate. The airflow and temperature distributions and ventilation flow rates were predicted using Computational Fluid Dynamics (CFD). The three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations were solved using the CFD tool ANSYS FLUENT15. The standard k-epsilon was used as turbulence model. The modelling was verified using grid sensitivity and flux balance analysis. In order to validate the modelling method used in the current study, additional simulation of a similar domed-roof building was conducted for comparison. For wind-induced ventilation, the dome building was modelled with upper roof vents. For buoyancy-induced ventilation, the geometry was modelled with roof vents and also with two windows open in the lower level. The results showed that using the upper roof openings as a natural ventilation strategy during winter periods is advantageous and could reduce the indoor temperature and also introduce fresh air. The results also revealed that natural ventilation using roof vents cannot satisfy thermal requirements during hot summer periods and complementary cooling solutions should be considered. The analysis showed that buoyancy-induced ventilation model can still generate air movement inside the building during periods with no or very low wind.

Mihi Breccia: A stack of lacustrine sediments and subaqueous pyroclastic flows within the Taupo Volcanic Zone, New Zealand

The Taupo Volcanic Zone (TVZ), New Zealand, encompasses a wide variety of arc-related strata, although most of its small-volume (non-caldera-forming) eruptions are poorly-exposed and extensively hydrothermally altered. The Mihi Breccia is a stratigraphic sequence consisting of interbedded rhyolitic pyroclastic flows and lacustrine sediments with eruption ages of 281±18 to at least 239±6ka (uncertainties at 2σ). In contrast to other small-volume rhyolitic eruptions within the TVZ, Mihi Breccia is relatively well-exposed within the Paeroa fault block, and contains minimal hydrothermal alteration. Pyroclastic flow characteristics and textures include: 1) prismatically jointed juvenile clasts, 2) lack of welding, 3) abundant ash-rich matrix, 4) lack of fiamme and eutaxitic textures, 5) lack of thermal oxidation colors, 6) lack of cooling joints, 7) exclusive lacustrine sediment lithic clasts, and 8) interbedding with lacustrine sediments, all indicating that Mihi Breccia strata originated in a paleo-lake system. This ephemeral paleo-lake system is inferred to have lasted for >50kyr (based on Mihi Breccia age constraints), and referred to as Huka Lake. Mihi Breccia pyroclastic flow juvenile clast geochemistry and petrography correspond with similar-aged (264±8, 263±10, and 247±4ka) intra-caldera rhyolite domes filling the Reporoa caldera (source of the ~ 281 ka Kaingaroa Formation ignimbrite). These exposed intra-caldera rhyolite domes (as well as geophysically inferred subsurface domes) are proposed to be source vents for the Mihi Breccia pyroclastic flows. Soft-sediment deformation associated with Mihi Breccia strata indicates either seismic shock, rapid sediment loading during pyroclastic flow emplacement, or both. Thus, the Mihi Breccia reflects a prolonged series of subaqueous rhyolite dome building and associated pyroclastic flows, accompanied by seismic activity, emplaced into a large paleo-lake system within the TVZ.