Understanding Mud Volcano System Using Hele-Shaw (H-S) Experiment: Seismic Confirmation at East Java Mud Volcano

Numerous researchers have carried out studies on the mud volcano system in East Java. However, there have been no experiments on the mud volcano system's mechanism, including overpressure confirmed by direct subsurface data. Therefore, this study aims to directly evaluate the mud volcano system's mechanism using the Hele-Shaw (H-S) experiment with the subsurface data confirmation. The H-S experiment utilized four primary materials: quartz sand diameter below 250 µm and 320 µm to analogize the porous layer. Gypsum flour clay is the ductile layer, while mud from the Kuwu and Kesongo Mud Volcanoes is the original material from nature. Wax represents impermeable material. The sealing layer is made of wax, and oxygen represents the natural fluids of the rock formation. The overpressured zone is created by pumping oxygen into a layer of quartz sand covered by a wax as an impermeable layer. Pressure is measured digitally, and the process is continuously recorded to produce traceable data. Each material was experimented on individually to determine the critical phase characteristics, valve fault structure geometry, and validation with seismic interpretation. The results indicate that the critical phase of the mud volcano system is characterized by the dome structure at the surface, with high intensify of gas and oil seepage. Piercement structure geometry is shown by plumbing of fluidization zone, which becomes shallower than before. Furthermore, each material's piercement structure geometry shows a consistent pattern, with differences in the density of the fault and pressure structures. Thus, the H-S experiment's validation with seismic interpretation shows a similar geometry in pressure structures and valve faults as the mud volcano system's migration paths.

The optimization process leading to the tessellation of the first geodesic dome structure, the first Planetarium of Jena

The tessellation of the first built geodesic dome structure (the first planetarium of Jena, designed by Walther Bauersfeld, built 1922–23) has been unknown until recently. While original documentation of the tessellation has been published, the concept behind it has not been uncovered. This article presents the evolution of the final tessellation based on Bauersfeld’s hand-written notes found in the Zeiss Archives in Jena. Bauersfeld contemplated various methods of subdivision and performed detailed calculations and optimality analysis on them—preceding the theoretical studies on the tessellation of geodesic domes by almost 30 years. His key findings, relevant and comparable with later studies are highlighted. The concept of the presumably final tessellation is revealed to be the equal-area triangulation of the sphere—which has to the author’s knowledge not been considered ever since for geodesic domes. The remarkably simple algorithm applied did not result in a theoretically exact solution (well known to Bauersfeld), but as shown in this article in engineering terms it got sufficiently close. Moreover, it is concluded that the resulting tessellation excels in terms of important parameters (e.g. edge length ratio, number of different edges) compared to existing practical and theoretical solutions.

Structural Analysis and 3D Timber Spatial Structure Modeling

The analysis of the structural form of the multi-volume dome structure using load-bearing wooden arches is performed. The complexity of the volumes and their connecting lines, as well as the requirement to conduct a non-linear analysis of long-span wooden elements at the request of Eurocode 5 make the information model necessary. It is noted that the design using this technology is developing in the direction of taking into account all stages of the structure life cycle. Information modeling of wooden structures in the world is the most prepared for the use of BIM-technologies. This is due to the sophisticated digital technologies for the production of modern wooden structures elements. An information model was formed for designing according to the regulations of Ukraine. The Information Model was created in the SAPFIR software package for further possibility of importing the model into the LIRA-CAD software package. The necessary auxiliary steps were used to build the model. The loads on the curved surface were calculated in the PC Espri. For further development of the nodes, 3D-modeling was used with the transfer of the information model into the PC Tekla Structures as a specialized environment for the constructive section of the project. The presented analysis of the complex dome structure using wooden arches summarizes the approaches to the development of unique forms of structures using wood. The use of information models has significantly increased the complexity of architectural design and structural model taking into account the nonlinear effects of wood. The possibility of integrating these tools for further implementation in BIM-technology is shown.

Comparison of the Spreading Characters of Fire Products in the Typical Metro Stations of Washington, D.C., and Guangzhou

Fire is one of the most common disasters that threaten the safety of the crowd in metro stations. Due to the variations in the design of metro stations, the hazard posed by the spreading products of the fire can pose different risks. The typical structures of metro stations in Guangzhou and Washington, D.C., are very different from each other. In Washington, D.C., the “high-dome” structure is predominant in the construction of metro stations, while in Guangzhou, most metro stations have the “flat ceiling” structure. In this article, a numerical modeling for fire dynamic simulation is used to predict and compare the spreading characters of fire products (the smoke height change, the temperature distribution and the visibility change) when fires with 2.5 MW heat release rate occur in the platform center and at the platform end in the two kinds of metro stations. The results show that, in the same fire scenario, the lowest smoke heights monitored in the Guangzhou model is 0.6 m (fire at the platform end) and 0.8 m (fire in the platform center) above the safe smoke height in 360 s after a fire breaks out, while it is 6.15 m (fire in the platform center) and 6.2 m (fire at the platform end) above the smoke height in the Washington model. The temperature increment in the Guangzhou model is 23 °C (fire in the platform center) to 29 °C (fire at the platform end) in 360 s after the fire breaks out, while the temperature increment in the same period in the Washington model is 8.5 °C (fire at the platform end) to 9 °C (fire in the platform center). The visibility of most areas on the platform of the Guangzhou model is about 1 m no matter the fire is in the platform center or at the platform end at 360 s after the fire begins, while in the Washington model, the visibility of most areas is 1.5–13.5 mm (fire at the platform end) to 4–14 m (fire in the platform center) at the same moment. Based on the results, the environment is worse when the fire happens at the end of the platform than that when the fire happens in the platform center of the Guangzhou model. While the fire location has fewer impacts on the smoke height, temperature, and visibility in the Washington model, metro stations with a high-dome structure can be beneficial to fire evacuation safety; however, the construction cost can be high. Metro stations with flat ceiling are widely used in more cities for it has lower construction cost; to compensate for its weaker abilities under fire conditions, it is suggested that smoke exhaust systems should be carefully and fully considered.

Innovative Joint for Cable Dome Structure Based on Topology Optimization and Additive Manufacturing

Aiming at the problems of a low material utilization rate and uneven stress distribution of cast-steel support joints in cable dome structures, topology optimization and additive manufacturing methods are used for optimization design and integrated manufacturing. First, the basic principle and calculation process of topology optimization are briefly introduced. Then, the initial model of the support joint is calculated and analyzed by using the universal software ANSYS Workbench 2020R2 and Altair OptiStruct, and the optimized joint is imported into Discovery Live to smooth the surface. The static behaviors of three types of joints (topology-optimized joints, joints after the smoothing treatment, and joints from practical engineering) are compared and analyzed. Finally, the joints are printed by using fused deposition modeling (FDM) technology and laser-based powder bed fusion (LBPBF) technology in additive manufacturing. The results show that the new support joint in the cable dome structure obtained by the topology optimization method has the advantages of a novel shape, a high material utilization rate, and a uniform stress distribution. Additive manufacturing technology can allow the manufacture of complex shape components with high precision and high speed. The combination of topology optimization and additive manufacturing effectively realizes the advanced design and integrated manufacturing of support joints for cable dome structures.

BIM-TECHNOLOGY METHOD AND MODELS IN THE DESIGN OF THE AQUAPARK DOME STRUCTURE WITH WOODEN ARCHES

Тhe issues of designing a multi-volume dome structure for a water park using wooden arches as load-bearing structures are сonsidered. The complexity of the volumes and their joining lines, as well as the requirement to perform non-linear analysis of large-span timber elements at the request of Eurocode 5, make an information model with elements of BIM-technology necessary. It is noted that design using this technology is developing in the direction of taking into account all stages of the structure life cycle. Wood Information modeling is the most prepared for the use of BIM-technologies. This is due to the high factory readiness and complex digital technologies for the manufacture of modern wooden structures elements. During the design, an information model was formulated in the SAPFIR software package with the subsequent possibility of importing the model into the LIRA-SAPR software package. Additional steps were used to build the model: creating a 2D template in AutoCad with reference lines and the location of rigid walls on which the coating rests, and importing drawings into SAPFIR as a dxf-underlay; for all elements of the system located in the local coordinate system, auxiliary lines were built for the correct orientation of the plane in space; loads on curved surfaces were calculated in the PC Expri. For the further development of the nodes, 3D modeling was used with the transfer of the information model to the Tekla Structures PC as a specialized environment for the constructive section of the project. The presented calculation of a complex dome structure using wooden arches summarizes the approaches to the development of unique forms of structures using wood. The use of information models made it possible to reduce the time spent on design, to optimize the drawings, and also to significantly increase the complexity of the architectural and structural design of the structure and the design model, taking into account the nonlinear effects of wood.

Experimental study of a solar water treatment device with dome structure cover in winter: performance evaluation and comparative analysis

In this paper, a dome slope single basin solar still for water treatment and desalination is presented. This new solar still device is based on installing a dome slope cover on the walls of the solar still. The main objective of such still is to concentrate more sunrays at the still's bottom basin, through the increased area of dome glass cover. Experiments are conducted under the climate conditions in Hangzhou city, China, for testing the operational performance of dome slope type solar still and the fourfold slope still, so as to make a comparative analysis between them. Assessment of the dome slope still's feasibility is performed based on energy, exergy, exergoeconomic, and enviroeconomic methodologies, as well as energy payback time. Results show that the productivity of dome slope still is 36% higher than that of fourfold slope still, and dome slope solar still enhances the average hourly energy efficiency by 34%. Due to the higher energy and exergy outputs of dome slope solar still throughout its lifetime, the novel solar still proposed in this study mitigates more CO2 compared to the fourfold slope still. Overall, incorporation dome slope cover with the still is found promising in terms of freshwater yield, cost, and energy payback time compared to conventional one. The dome slope single basin solar still appears to be effective from exergoeconomic, exergoenvironmental parameters analysis.

ROMNY SALT DOME STRUCTURE (DNIPRO-DONETS BASIN): GEOLOGICAL HISTORY AND HYDROCARBON POTENTIAL

The geological structure of the Romny salt dome and related the Romny oil field as the first discovered one in the Eastern region of Ukraine are described. The history of its discovery and development of the field are featured. The geological and geophysical study of this area is characterized. Under generalization of geological and geophysical data, paleotectonic and peleogeothermal reconstructions on the Romny structure derived from the results of drilling of Gerasymivska-1 exploration well. The cyclic intermittent development of the salt dome structure is demonstrated. It is proved that the upper intersalt Frasnian source rocks could generate hydrocarbons starting from the early Visean time. According to the results of seismic surveys the uplifted block is outlined in the area of the northern edge of the salt dome. The presence of hydrocarbon pools in of the Visean and Serpukhovian granular reservoirs as well as in the salt breccia is predicted applying seismic attributes analysis for this block. The carbonate reservoirs of the lower part of the Bashkirian sequence, the productivity of which is established at the nearest located Velyki Bubny field, can be potentially oil and gas-bearing.