Deep Geothermal Well Construction Problems and Possible Solutions

The geothermal energy is one of the most promising sources of electricity on the planet; it is available almost anywhere on the continents and resources are inexhaustible. The realization of these possibilities requires solving the problems of deep wells (6-10 km) construction, when the lower horizons are practically impermeable crystalline basement rocks. For effective use of the Earth's heat, bottomhole temperatures must be within 200-300°C. World experience of such deep wells construction is very limited, some examples are given in this work. Known schemes of geothermal energy application requires at least two wells construction - for cold fluid injection and superheated fluid production. The rock - circulating fluid heat exchange in the bottomhole requires drilling of inclined, horizontal, or multi-lateral boreholes and hydraulic fracturing application. Such technologies are widely used in the oil and gas fields, but not in crystalline rocks. The article presents an analysis of the prospects for the geothermal wells construction efficiency increasing by using modern directional drilling systems, drilling with casing, technologies for complications eliminating. The possibilities of using alternative hard rock drilling methods by enhancing the standard formation destruction with drill bits are discussed. These are hydraulic hammers, high-pressure abrasive and fluid jets, laser drilling. A fundamentally new plasma drilling technology is considered. The most serious limitation of alternative drilling prospects is the need of additional "supply lines" to the bottom: high-pressure fluid; electricity; a plasma forming agent, etc. In this regard, options are being considered for the development of continuous drill strings such as coiled tubing, umbilical, flexible composite systems like subsea pipelines. Some of technological solutions for deep geothermal wells construction, and implementation of petrothermal energy schemes for potential projects are proposed. The paper provides an idea of the geothermal well construction technologies, which can ensure the implementation of advanced geo-energy schemes. The problems of geothermal engineering and possible solutions to overcome them, which will contribute to the development of geothermal energy, as the most effective option for decarbonization, are indicated.

Use of an Oxygen Planar Optode to Assess the Effect of High Velocity Microsprays on Oxygen Penetration in a Human Dental Biofilms In-Vitro

BackgroundDental plaque biofilms are the causative agents of caries, gingivitis and periodontitis. Both mechanical and chemical strategies are used in routine oral hygiene strategies to reduce plaque build-up. If allowed to mature biofilms can create anoxic microenvironments leading to communities which harbor pathogenic Gram-negative anaerobes. When subjected to high velocity fluid jets and sprays biofilms can be fluidized which disrupts the biofilm structure and allows the more efficient delivery of antimicrobial agents.MethodsTo investigate how such jets may disrupt anoxic niches in the biofilm, we used planar optodes to measure the dissolved oxygen (DO) concentration at the base of in-vitro biofilms grown from human dental saliva and plaque. These biofilms were subject to “shooting” treatments with a commercial high velocity microspray (HVM) device.ResultsHVM treatment resulted in removal of much of the biofilm and a concurrent rapid shift from anoxic to oxic conditions at the base of the surrounding biofilm. We also assessed the impact of HVM treatment on the microbial community by tracking 7 target species by qRT-PCR. There was a general reduction in copy numbers of the universal 16S RNA by approximately 95%, and changes of individual species in the target region ranged from approximately 1 to 4 log reductions.ConclusionWe concluded that high velocity microsprays removed a sufficient amount of biofilm to disrupt the anoxic region at the biofilm-surface interface.

Use of an Oxygen Planar Optode to Assess the Effect of High Velocity Microsprays on Oxygen Penetration in a Human Dental Biofilms In-Vitro

Background Dental plaque biofilms are the causative agents of caries, gingivitis and periodontitis. Both mechanical and chemical strategies are used in routine oral hygiene strategies to reduce plaque build-up. If allowed to mature biofilms can create anoxic microenvironments leading to communities which harbor pathogenic Gram-negative anaerobes. When subjected to high velocity fluid jets and sprays biofilms can be fluidized which disrupts the biofilm structure and allows the more efficient delivery of antimicrobial agents. Methods To investigate how such jets may disrupt anoxic niches in the biofilm, we used planar optodes to measure the dissolved oxygen (DO) concentration at the base of in-vitro biofilms grown from human dental saliva and plaque. These biofilms were subject to “shooting” treatments with a commercial high velocity microspray (HVM) device. Results HVM treatment resulted in removal of much of the biofilm and a concurrent rapid shift from anoxic to oxic conditions at the base of the surrounding biofilm. We also assessed the impact of HVM treatment on the microbial community by tracking 7 target species by qRT-PCR. There was a general reduction in copy numbers of the universal 16S RNA by approximately 95%, and changes of individual species in the target region ranged from approximately 1 to 4 log reductions. Conclusion We concluded that high velocity microsprays removed a sufficient amount of biofilm to disrupt the anoxic region at the biofilm-surface interface.

Use of an Oxygen Planar Optode to Assess the Effect of High Velocity Microsprays on Oxygen Penetration in a Human Dental Biofilms In-Vitro

Background Dental plaque biofilms are the causative agents of caries, gingivitis and periodontitis. Both mechanical and chemical strategies are used in routine oral hygiene strategies to reduce plaque build-up. If allowed to mature biofilms can create anoxic microenvironments leading to communities which harbor pathogenic Gram-negative anaerobes. When subjected to high velocity fluid jets and sprays biofilms can be fluidized which disrupts the biofilm structure and allows the more efficient delivery of antimicrobial agents. Methods To investigate how such jets may disrupt anoxic niches in the biofilm, we used planar optodes to measure the dissolved oxygen (DO) concentration at the base of in-vitro biofilms grown from human dental saliva and plaque. These biofilms were subject to “shooting” treatments with a commercial high velocity microspray (HVM) device. Results HVM treatment resulted in removal of much of the biofilm and a concurrent rapid shift from anoxic to oxic conditions at the base of the surrounding biofilm. We also assessed the impact of HVM treatment on the microbial community by tracking 7 target species by qRT-PCR. There was a general reduction in copy numbers of the universal 16S RNA by approximately 95%, and changes of individual species in the target region ranged from approximately 1 to 4 log reductions. Conclusion We concluded that high velocity microsprays removed a sufficient amount of biofilm to disrupt the anoxic region at the biofilm-surface interface.

Use of an Oxygen Planar Optode to Assess the Effect of High Velocity Microsprays on Oxygen Penetration in a Human Dental Biofilms In-Vitro

Background Dental plaque biofilms are the causative agents of caries, gingivitis and periodontitis. Both mechanical and chemical strategies are used in routine oral hygiene strategies to reduce plaque build-up. If allowed to mature biofilms can create anoxic microenvironments leading to communities which harbor pathogenic Gram-negative anaerobes. When subjected to high velocity fluid jets and sprays biofilms can be fluidized which disrupts the biofilm structure and allows the more efficient delivery of antimicrobial agents. Methods To investigate how such jets may disrupt anoxic niches in the biofilm, we used planar optodes to measure the dissolved oxygen (DO) concentration at the base of in-vitro biofilms grown from human dental saliva and plaque. These biofilms were subject to “shooting” treatments with a commercial high velocity microspray (HVM) device. Results HVM treatment resulted in removal of much of the biofilm and a concurrent rapid shift from anoxic to oxic conditions at the base of the surrounding biofilm. We also assessed the impact of HVM treatment on the microbial community by tracking 7 target species by qRT-PCR. There was a general reduction in copy numbers of the universal 16S RNA by approximately 95%, and changes of individual species in the target region ranged from approximately 1 to 4 log reductions. Conclusion We concluded that high velocity microsprays removed a sufficient amount of biofilm to disrupt the anoxic region at the biofilm-surface interface.

A brief history of liquid computers

A substrate does not have to be solid to compute. It is possible to make a computer purely from a liquid. I demonstrate this using a variety of experimental prototypes where a liquid carries signals, actuates mechanical computing devices and hosts chemical reactions. We show hydraulic mathematical machines that compute functions based on mass transfer analogies. I discuss several prototypes of computing devices that employ fluid flows and jets. They are fluid mappers, where the fluid flow explores a geometrically constrained space to find an optimal way around, e.g. the shortest path in a maze, and fluid logic devices where fluid jet streams interact at the junctions of inlets and results of the computation are represented by fluid jets at selected outlets. Fluid mappers and fluidic logic devices compute continuously valued functions albeit discretized. There is also an opportunity to do discrete operation directly by representing information by droplets and liquid marbles (droplets coated by hydrophobic powder). There, computation is implemented at the sites, in time and space, where droplets collide one with another. The liquid computers mentioned above use liquid as signal carrier or actuator: the exact nature of the liquid is not that important. What is inside the liquid becomes crucial when reaction–diffusion liquid-phase computing devices come into play: there, the liquid hosts families of chemical species that interact with each other in a massive-parallel fashion. I shall illustrate a range of computational tasks, including computational geometry, implementable by excitation wave fronts in nonlinear active chemical medium. The overview will enable scientists and engineers to understand how vast is the variety of liquid computers and will inspire them to design their own experimental laboratory prototypes. This article is part of the theme issue ‘Liquid brains, solid brains: How distributed cognitive architectures process information’.

Theoretical and practical aspects of the Coandă effect applied in aeronautics

The Coandă Effect, or better said, the deviation of fluid jets to stay attached to a convex surface is a complex gas-dynamic effect, named after the Romanian aviation engineer Henri Coandă and it was for the first time highlighted by him in 1910 during the take-off of one of his first planes, Coandă-1910, which was also the first jet plane to fly. During the short flight, Coandă was able to notice the near-fit alignment of the flue gas jets with the airplane fuselage. Later, both Coandă and other scholars have intensively studied the effect that is named The Coandă Effect, in his honor.