Displacement Process Research Articles

Wettability impacts residual trapping of immiscible fluids during cyclic injection

Understanding the hysteretic behaviour in fluid–fluid displacement processes in porous media is critical in many engineering applications. In this work, we study the quasi-static immiscible displacement process in two-dimensional porous media during cyclic injections in the context of carbon geosequestration. The role of wettability on the residual trapping of CO $_2$ is investigated numerically using an extended interface tracking algorithm. Despite that higher CO $_2$ saturation can be achieved in CO $_2$ -wet porous media after the first CO $_2$ injection, the majority of CO $_2$ is found to be unstable and can be mobilised during subsequent water injection processes. An improvement in the residual trapping of CO $_2$ is observed as the number of injection cycles increases, which is associated with the dispersion of continuous CO $_2$ ganglia into numerous smaller blobs. Compared with either water-wet or CO $_2$ -wet porous media, it is found that less CO $_2$ is trapped within the neutral-wet ones at equilibrium state after a sufficient number of injection cycles. The hysteretic behaviour of saturation between water/CO $_2$ injection cycles is found to follow an exponential decay, which eventually reaches a finite value. This process corresponds to the shift of the mobile region during displacement from typical capillary fingering to a less ramified regime, which ultimately converges towards main flow channels. This work highlights the hysteretic behaviour during cyclic injections, providing insights on the wettability impacts on multiphase flow in porous media, which is of great importance in applications such as carbon geosequestration and geological hydrogen storage.

When a dominant certified management standard is replaced: theoretical insights from the American hospital field

PurposeDominant quality standards are present in all industries. Implicit in their use is the assumption that once adopted, there is little or no reason to replace them. However, there is evidence that, under certain circumstances, such standards do get replaced. The reasons for this action are not well-understood, either as they pertain to the displacement decision or to the selection and adoption of the alternative standard. The purpose of this study is to identify and explore these two issues (displacement and replacement) by drawing on data from the American healthcare system. This study is viewed through the theoretical lens of legitimacy theory. In addition, the process is viewed from a temporal perspective. The resulting findings are used to better understand how this displacement process takes place and to identify directions for interesting and meaningful future research.Design/methodology/approachThis is an explanatory study that draws on data gathered from quality managers in 89 hospitals that had adopted a new healthcare quality standard (of these, some fifty percent had displaced the dominant quality standard – the Joint Commission – with a different standard – DNV Healthcare.FindingsThe combined literature review and case study data provide insights into the displacement process. This is a process that evolves over time. Initially, the process is driven by the need to meet customer demands. However, over time, as the organizations try to integrate the guidelines contained within the standards into the organization, gaps in the quality standard emerge. It is these gaps that motivate the need to displace standards. The legitimacy perspective is highly effective at explaining this displacement process. In addition, the study uncovers some critical issues, namely the important role played by the individual auditors in the certification process and the importance of fit between the standard and the context in which it is deployed.Research limitations/implicationsThe data for the propositions in this case study were derived from interviews and survey data from 89 healthcare organizations. It would be interesting to examine similar relationships with other quality standards and industries.Practical implicationsOur findings provide new insights related to motivations to decouple from a dominant quality standard. Results provide a cautionary tale for standards that hold a dominant market share such that perceived legitimacy of such standards is not as stable as originally thought.Originality/valueThis study illuminates the fragile nature of the stability of dominant standards and emphasizes the linkages between legitimacy concerns and divestiture of such standards.

PROSPECTIVE PHYSICO-CHEMICAL METHODS OF INCREASING THE RECOVERY (EOR) FOR OIL FIELDS WITH THE CATEGORY OF HARD-TO-EXTRACT OILS

It is known that many technologies to improve the oil recovery factor in fields at a late stage of development are being used. However, there are no universal technologies that ensure the effective displacement of residual oil in the reservoir by changing the filtration and volumetric parameters of rocks and the rheological properties of fluids depending on the geological characteristics of the reservoirs. In the article, based on the analysis of well-known works carried out on the selection of the appropriate oil for displacement oil in the reservoir, taking into account changes in some reservoir parameters, research work was conductedwith the purpose to prepare a new composition. The question of searching for a composition capable of maintaining oil-displacing properties at different temperatures in reservoir conditions, not changing its viscosity at large temperature differences, and also capable of retaining the properties of removing oil particles absorbed there from the surface in contact with the reservoir is relevant. the surface of the rock was examined by laboratory studies. The viscosities of the found composition at various temperatures were determined using a viscometer, and the optimal composition with a stable viscosity was determined by replacing the components with numerous laboratory experiments. Under laboratory conditions, the process of displacement of oil under various compositions with a slug of the composition at different temperatures was carried out. The results obtained are satisfactory, and the effective behavior of the composition at bed temperatures of 30-80 0C has been experimentally confirmed. If we take into account that the compositions injected into the reservoir undergo certain changes under the influence of reservoir temperature and pressure, then certain changes in its properties will inevitably occur when the composition comes into contact with reservoir fluids. Therefore, the ability of the prepared composition to form a precipitate or gel upon contact with various formation waters was also studied. The results of laboratory studies of physical and chemical technologies for enhanced oil recovery in fields treated by water injection and thermochemical treatment are presented. These technologies can be used in reservoirs with hard-to-recover reserves of high-viscosity oil. Keywords: viscosity, residual reserve, bed, surfactant, gel, oil displacer.

New error estimators, based on the Neumann-Monte Carlo methodology for quantification of the uncertainty of the problem of stochastic bending of Levinson-Bickford beam

This paper proposes to apply the Neumann – Monte Carlo method to obtain the estimates of the statistical moments of the solution for stochastic bending problem of Levinson-Bickford beams, with uncertainty in beam stiffness. The approximate solutions represent the stochastic displacement processes. For uncertainty modeling, parameterized stochastic processes will be used. The methodology proposed in this work differs from the usual one, as it is developed from theoretical results of existence and uniqueness of the realizations. The consistency of the approximate solutions will be based on studies on the existence and uniqueness of the theoretical solutions to this problem. In addition, error estimates are presented for the statistical moments of the beam response. The uncertainty will be quantified by estimating the statistical moments of the stochastic transverse displacement processes. The Monte Carlo simulation method is used to evaluate the performance of the proposed methodology.

Analysis of influencing factors on gas film characteristics for hemispherical dynamic pressure motors

The hemispherical dynamic pressure motor (HDPM) has the advantages of high speed, wear resistance and stability, which is widely used in inertial instruments to produce the gyroscopic effect. The ultra-thin gas film between the stator and rotor of the motor provides dynamic pressure lubrication and bearing capacity, whose dynamic characteristics determine the motor performance. However, the influence mechanism of some key factors such as ball center distance on the film characteristics is not clear, which has become the bottleneck restricting the performance improvement of HDPMs. Therefore, in this paper, a series of gas film similarity models were solved under different geometric and working parameters, and the influence law of the ball center distance, rotor displacement and stopping process on the aerodynamic characteristics was obtained, the results show that these primary parameters have significant effects on the pressure distribution, resistance moment and frictional heat of the ultra-thin gas film. This work can not only provide a theoretical basis for the aerodynamic performance optimization of HDPMs, but also serve as a reference for the design of other aerodynamic instruments.

Study on the Instability Mechanism of Coal and Rock Mining under a Residual Coal Pillar in Gently Inclined Short-Distance Coal Seam with the Discrete Element

The collapse of overlying rocks caused by the instability of residual coal pillars during lower coal seam mining significantly impacts its safety. This paper focuses on the gentle dipping coal seam group and utilizes the discrete element method (DEM) as the basis to comprehensively consider multiple factors through orthogonal experiments. In so doing it reveals the influence mechanisms of various factors on mining at a close distance under a residual coal pillar. Firstly, the process of lower coal seam mining under residual coal pillars in gently-dipping coal seams was simulated and analyzed based on a case study at the Baoping coal mine. Comparing the evolution characteristics of coal–rock fractures, stress changes, and displacement changes during the mining process reveals the mechanism of the joint instability of the lower coal seam, interlayer rock, coal pillars, and overlying strata under the disturbed conditions of lower panel mining. Secondly, an orthogonal simulation experiment was established using the width of the coal pillar and the thickness of the lower coal seam as variables. By comparing the development process of cracks, stress distribution, and rock displacement under different conditions, the research results indicate that the width of coal pillars has an impact on the maximum amount of coal pillar subsidence, while the thickness of the underlying coal seam has an impact on the time of subsidence, when hd ≥ 4.2 m (hj/hd ≤ 4) and w ≤ 14 m (w/hm ≤ 2), a large-scale collapse of the overlying strata of the coal pillar occurs.

“Development” definitions of internally displaced people and the government: A study of the Chenchu tribe in the Nallamala forest of southern India

The Government of India’s twin objectives of protecting the tiger population in the Nallamala forest and providing “development” to the indigenous Chenchu people have resulted in an ongoing process of displacement of the Chenchu people from the forest to the town fringes. While the conservation-displacement nexus has bridged new anthropocentric pathways for development, it has also created deeper crevices in the innate relationships of the Chenchu with the forests and tigers. The research uses a bottom-up approach to present on-the-ground realities of conservation and development policies of the Indian Government and the Chenchu people, particularly, the Chenchu’s development expectations, relationship with the forest and tigers, and displacement views as well as the government’s tiger conservation objectives, development promises, and perspectives on Chenchu development and forest conservation. The paper is a comparative study of the definitions of “development” held by the internally displaced Chenchu people and the Indian government representatives of the Integrated Tribal Development Agency and the Nagarjunasagar Srisailam Tiger Reserve, and the local non-government organizations that collaborate with the Government.

Impact of surface roughness, surface charge, and temperature on sandstone wettability alteration by nanoparticles

The wettability of rocks affects the balance between capillary and viscous forces during multiphase flow through porous media, which in turn determines the fluid displacement process governing the recovery of oil from subsurface formations. In this work, the mechanism of wettability reversal of aged synthetic sandstones by metal oxide nanoparticles (SiO2 and Al2O3) was investigated with particular focus on the impact of surface roughness, zeta potential, and temperature. The synthetic surfaces were prepared from powders of Berea sandstone with known grain size ranges and their average roughness and roughness ratio were obtained from the 3D surface reconstruction of their microscope images. Each surface was subsequently aged in Permian crude oil to alter its wettability. For surfaces with larger grain sizes and lower surface roughness ratios, the lower capillary pressure allowed stronger oil/surface interactions, leading to enhanced oil-wetness. The wettability alteration effects of nanoparticles were then examined through real-time top view imaging and dynamic front view contact angle experiments. The negatively charged SiO2 nanoparticles rapidly reversed the sandstone wettability, indicating their potential applicability as wettability alteration agents. By contrast, the positively charged Al2O3 counterpart caused no wettability reversal. The mechanism of wettability alteration was further studied by microscale interaction analyses and nanoscale transmission electron microscopy. Because nanoparticles were only a few nanometers large, the microscale roughness had a negligible effect on the wettability reversal. Instead, the combined effect of van der Waals dispersion forces and surface-charge-induced electrostatic forces were recognized as the two key factors affecting the wettability of sandstone particles. Such interactions may be curbed at elevated temperatures due to a decrease in the zeta potential and colloidal stability of the particles.

Near-ultraviolet absorption distribution of primitive asteroids from spectrophotometric surveys

Context. Hydrated minerals, such as phyllosilicates, on asteroids can provide constraints on the temperature or compositional distribution of the early Solar System. Previous studies pointed out the possibility that absorption in the near-ultraviolet (NUV, 0.35–0.5 μm) wavelength region is a proxy for hydrated minerals in primitive asteroids. However, the radial distribution of the NUV absorption among primitive asteroids was not revisited after the Eight Color Asteroid Survey (ECAS). Aims. Our objectives are first to evaluate the possibility of using the NUV absorption as diagnostics of hydrated minerals based on the recent datasets of primitive asteroids and hydrated carbonaceous chondrites, and second to investigate the reflectance spectrophotometry of the primitive asteroids in the NUV as functions of heliocentric distance and size. Methods. The NUV and visible reflectance spectrophotometry of more than 9000 primitive asteroids was investigated using two spectrophotometric surveys, ECAS and the Sloan Digital Sky Survey (SDSS), which cover wavelengths down to 0.32 μm and 0.36 μm, respectively. We classified asteroids from the main asteroid belt, the Cybele and Hilda zones, and Jupiter Trojans based on Tholen’s taxonomy and described the statistical distribution of primitive asteroid types. We also examined the relationship of the NUV, 0.7 μm, and 2.7 μm absorptions among primitive asteroids and hydrous carbonaceous chondrites CI and CM. Results. We find strong correlations between the NUV and the OH-band (2.7 μm) absorptions for primitive asteroids and hydrated meteorites, suggesting the NUV absorption can be indicative of hydrated silicates. Moreover, there is a great difference in the NUV absorption between the large asteroids (diameter d > 50 km) and small asteroids (d < 10 km) in the taxonomic distribution. The taxonomic distribution of asteroids differs between the inner main belt and middle-outer main belt. Notably, the C types are dominating large members through the main belt and the F types are dominating small asteroids of the inner main belt. The asteroids beyond the main belt consist mostly of P and D types, although P types are common everywhere in the main belt. The peculiar distribution of F types might indicate a different formation reservoir or a displacement process of F types in the early Solar System. The strongest absorptions of the NUV and 0.7 μm band were observed in G types, which likely comprise CM-like Fe-rich phyllosilicates. On the other hand, according to a recent sample return from an F-type asteroid (162173) Ryugu, the F types with the OH-band at 2.7 μm and the shallow NUV absorption could comprise CI-like Mg-rich phyllosilicates.

Numerical simulation of water shut-off performance for heterogeneous layered oil reservoirs

This paper proposes a hydrodynamic model of two-phase three-component fluid filtration in a layered heterogeneous reservoir that takes into account cross-flows between layers and allows prediction of the process of oil displacement by water under conditions of water shut-off near injection and production wells. The numerical calculations show that, in the absence of cross-flow between layers, the oil recovery factor for the entire reservoir is higher with water shut-off near the injection well than with water shut-off near the production well, and this effect grows as the water cut of the high permeability layer decreases. In the event of cross-flow across layers, the oil recovery factor in the entire reservoir is higher with water shut-off near the production well than with water shut-off near the injection well, and this impact grows when water cut in the high-permeability layer decreases. In the absence of crossflow, the gel washout time during water shut-off in the region of both injection and production wells is substantially longer than in the presence of crossflow. Keywords: hydrodynamic model; water shut-off; oil reservoir; gel; well.

"Step by Step We Were Okay Now": An Exploration of the Impact of Social Connectedness on the Well-Being of Congolese and Iraqi Refugee Women Resettled in the United States.

Little is known about the gendered impacts of the displacement and resettlement process. Women are known to struggle more with feelings of belonging and the creation of social networks to access essential information, resources, and social and emotional support to enhance their overall health and well-being. The purpose of the present study was to qualitatively explore female refugee perceptions of belongingness and social connectedness post-resettlement into their U.S. host community. Conducted between January and June of 2016, through the partnership of multiple governmental, nonprofit, and community-based organizations, two female focus groups were conducted among Congolese (n = 6) and Iraqi (n = 6) U.S. resettled refugees. Descriptive surveys were distributed to participants, providing valuable insights into participant demographics and indicators that could impact the integration process (i.e., age, language, country of origin, ethnicity, education, length of time spent in the U.S., housing). Participants discussed the social connections (individuals, communities, organizations) that acted as facilitators or inhibitors of developing social capital. The importance of building strong transformational bonding (family members, other refugees) and bridging (host community) relationships, alongside transactional ties with linking agencies (resettlement social services), was critical for a positive resettlement experience. The strength of their network ties among these social connections contributed to their perceptions of belongingness and well-being post-resettlement into their host community.

Combined electronic excitation and knock-on damage in monolayer MoS2

Electron irradiation-induced damage is often the limiting factor in imaging materials prone to ionization or electronic excitations due to inelastic electron scattering. Quantifying the related processes at the atomic scale has only become possible with the advent of aberration-corrected (scanning) transmission electron microscopes and two-dimensional materials that allow imaging each lattice atom. While it has been shown for graphene that pure knock-on damage arising from elastic scattering is sufficient to describe the observed damage, the situation is more complicated with two-dimensional semiconducting materials such as ${\mathrm{MoS}}_{2}$. Here, we measure the displacement cross section for sulfur atoms in ${\mathrm{MoS}}_{2}$ with primary beam energies between 55 and 90 keV, and correlate the results with existing measurements and theoretical models. Our experimental data suggests that the displacement process can occur from the ground state, or with single or multiple excitations, all caused by the same impinging electron. The results bring light to reports in the recent literature, and add necessary experimental data for a comprehensive description of electron irradiation damage in a two-dimensional semiconducting material. Specifically, the results agree with a combined inelastic and elastic damage mechanism at intermediate energies, in addition to a pure elastic mechanism that dominates above 80 keV. When the inelastic contribution is assumed to arise through impact ionization, the associated excitation lifetime is on the order of picoseconds, on par with expected excitation lifetimes in ${\mathrm{MoS}}_{2}$, whereas it drops to some tens of femtoseconds when direct valence excitation is considered.

Review of closed reduction techniques for femoral neck fracture

For patients with femoral neck fractures who plan to undergo internal fixation, satisfied alignment of fracture ends is an important prerequisite for internal fixation stability and fracture healing. There are many reports on the reduction methods of displaced femoral neck fractures, which can be summarized into three categories:First, the solely longitudinal traction of lower limbs, supplemented by other manipulations such as rotation and compression; Second, the resultant force formed by the longitudinal traction of lower limbs and the lateral traction;the third is accomplished by vertical traction in the axis of femur with hip joint flexed. Each reduction method has its own advantages, but no single method can be applied to all fracture displacement. In this paper, some classical reduction techniques in the literatures are briefly reviewed. It is hoped that clinicians will not be limited to a certain reduction method, they should analyze the injury mechanism and fracture displacement process according to the morphology features and flexibly select targeted reduction methods to improve the success rate of closed reduction of femoral neck fracture.

Construction of an Endogenously Activated Signal Amplification Assay for In Situ Imaging of MicroRNA and Guided Precise Photodynamic Therapy for Cancer Cells.

The construction of a sensitive strategy for in situ visualizing and dynamic tracing intracellular microRNA is of great importance. Via the toehold-mediated strand displacement process, the catalytic hairpin assembly (CHA) could offer several hundreds-fold signal amplifications. However, the CHA may produce certain background interferences since microRNA may exist in normal cells. In this work, we constructed an endogenously and sequentially activated signal amplification strategy to provide the amplified dual-color fluorescence imaging of microRNA in living cancer cells, which was comprised of two successive reaction processes: the activation of the preprotective catalytic probe by the endogenous glutathione (GSH) and the subsequent catalytic hairpin assembly on the surface of the upconversion nanoprobe triggered by the specific microRNA. Since the concentration of GSH in cancer cells was much higher than that in normal cells and the extracellular environment, the activation of the designed nanoprobe could be controlled at the desirable site. With the merits of the endogenous initiation and selective activation, the designed nanoprobe could achieve the bioimaging of microRNA in living cancer cells with high precision and reliability. Furthermore, via the introduction of a photosensitizer molecule into the DNA strand, the designed nanoplatform could achieve the precise photodynamic therapy (PDT) for cancer cells and malignant tumors under the irradiation of the NIR laser. This work provided a new avenue to achieve the accurate imaging of intracellular microRNA and guided precise PDT, which would offer powerful hints to the early diagnosis and therapy of malignant tumors.

Suppressing Viscous Fingering in Porous Media with Wetting Gradient.

The viscous fingering phenomenon often occurs when a low-viscosity fluid displaces a high-viscosity fluid in a homogeneous porous media, which is an undesirable displacement process in many engineering applications. The influence of wetting gradient on this process has been studied over a wide range of capillary numbers (7.5 × 10-6 to 1.8 × 10-4), viscosity ratios (0.0025 to 0.04), and porosities (0.48 to 0.68), employing the lattice Boltzmann method. Our results demonstrate that the flow front stability can be improved by the gradual increase in wettability of the porous media. When the capillary number is less than 3.5 × 10-5, the viscous fingering can be successfully suppressed and the transition from unstable to stable displacement can be achieved by the wetting gradient. Moreover, under the conditions of high viscosity ratio (M > 0.01) and large porosity (Φ > 0.58), wetting gradient improves the stability of the flow front more significantly.

Enhanced fluorescent detection of nucleic acid based on hairpin DNA-assisted toehold-mediated strand displacement reaction

A new hairpin DNA regulated strand displacement strategy for detection of nucleic acid is proposed via the conformational transformation of hairpin DNA. In this entropy-driven signal amplification strategy, we introduce a hairpin structure (single strand B) into a duplex strand which makes the entire strand displacement process easier and faster when the target DNA exists. The strand migration process of displacing the single strand B with the target is a process of constantly displacing bases. As the number of displaced bases increases, the stem ends of the B strand tend to be in a flexible state. When the number of bases is large enough, the two parts of the stem in B strand will undergo complementary base pairing. Therefore, in the subsequent displacement process, target DNA will displace strand B avoiding completely displacing all the bases at the end of the B strand. Regardless of thermodynamics or kinetics, the formation of this hairpin structure has a certain impetus for the displacement reaction. Since the entire reaction process is truly enzyme-free, simple to operate and low in cost, and thus is expected to provide a novel strategy for clinical analysis.

Rio 2016 Olympic Legacy for Residents of Favelas: Revisiting the Case of Vila Autódromo Five Years Later

The aim of this research was to explore and describe the long-term social impact the Rio 2016 Olympic gentrification had in Vila Autódromo from the perspective of former and current residents. Vila Autódromo is a small favela located next to the Rio 2016 Olympic Park. It was almost totally removed during the process of preparing the area to host the Games. In this research, I interviewed 13 residents who passed through the process of eviction threats and displacement. Five still live in Vila Autódromo, whilst eight moved to social apartments provided by the city hall. Interviews revealed that the legacy of Rio 2016 for Vila Autódromo residents can be understood from three broad themes: (1) disempowerment of the community, (2) resistance and resilience during the process, and (3) life after the Games. The residents see the city hall as the main culprit of their displacement, as they were denied their right to the city. However, they also mention the catalytic role of the Olympic Games during the process. They conclude that the legacy of Rio 2016 for them is a very sad story.

Simulation of Microscopic Seepage Characteristics of Interphase Mass Transfer in CO2 Miscible Flooding under Multiphysics Field Coupling Conditions.

CO2 miscible flooding in low permeability reservoirs is conducive to significantly improving oil recovery. At present, the microscopic displacement simulation of CO2 miscible flooding is mainly reflected in the simulation of the seepage process, but the pressure control of the seepage process is lacking, and the simulation of the characterization of CO2 concentration diffusion is less studied. In view of the above problems, a numerical model of CO2 miscible flooding is established, and the microscopic seepage characteristics of interphase mass transfer in CO2 miscible flooding are analyzed by multiphysics field coupling simulations at the two-dimensional pore scale. The injection velocity, contact angle, diffusion coefficient, and initial injection concentration are selected to analyze their effects on the microscopic seepage characteristics of CO2 miscible flooding and the concentration distribution in the process of CO2 diffusion. The research shows that after injection into the model, CO2 preferentially diffuses into the large pore space and forms a miscible area with crude oil through interphase mass transfer, and the miscible area expands continuously and is pushed to the outlet by the high CO2 concentration area. The increase in injection velocity will accelerate the seepage process of CO2 miscible displacement, which will increase the sweep area at the same time. The increase in contact angle increases the seepage resistance of CO2 and weakens the interphase mass transfer with crude oil, resulting in a gradual decrease in the final recovery efficiency. When the diffusion coefficient increases, the CO2 concentration in the small pores and the parts that are difficult to reach at the model edge will gradually increase. The larger the initial injection concentration is, the larger the CO2 concentration in the large pore and miscible areas in the sweep region at the same time. This study has guiding significance for the field to further understand the microscopic seepage characteristics of CO2 miscible flooding under the effect of interphase mass transfer.

Lessons learned and policy implications from climate-related planned relocation in Fiji and Australia

Planned Relocation is a form of mobility in response to climate-related shocks and slow onset change. While the primary focus of the seminal Foresight report on Migration and Environmental Change dealt with mobility processes of migration and displacement, planned relocation was discussed as a viable, yet fraught adaptation strategy. Since the publication of the Foresight report in 2011, considerable research into planned relocation has progressed understanding, in part due to the emerging case study examples globally over the last 10 years. The authors of this article have undertaken research in communities across Australia and Fiji who have initiated and undertaken planned relocation processes, to varying degrees of completion and success. As part of the Research Topic—Climate Migration Research and Policy Connections: Progress Since the Foresight Report—in this article we look back at the lessons that emerged from the Foresight report, and provide key insights from our experiences, as well as through drawing on the broader literature, and through doing so offer lessons learned, and policy insights for planned relocation across these regions, and beyond. This research is especially relevant given the context of planned relocation in these two nations: Australia, a country that has experienced severe fires and flooding events over the last few years, which have raised important questions around the role planned relocation may play in future national adaptation discussions and planning, with buy-back schemes occurring across the country; and Fiji, a country at the forefront of planned relocation globally, with 800 communities listed as in need of relocation by the Government of Fiji, and numerous cases of completed, initiated and planned relocation emerging. Primary findings indicate: there are examples of people choosing to remain in sites of exposure despite relocation plans, making the notion of “voluntariness” essential; relocation has the potential to be a successful adaptation option if planned well with strong participatory governance; a need to think broadly and holistically around the needs and livelihoods of effected communities in relocation planning; and the need for longitudinal studies to track the implications and impacts (both positive and negative) of relocation in the long term.

Development of ideas about the mechanism of coal-overlaying formation displacement in terms of its influence on local gas-drainage parameters in the Western Donbas conditions

Purpose. The research purpose is to study the mechanism of the influence of geomechanical-technological factors on the location parameters of the gas-drainage wells behind the longwall face in the area of stope operations under the conditions of weakly metamorphosed rocks. Research methodology. An integrated approach is used, including an analysis of existing research on the gas release patterns in the mine workings of extraction sites and local gas-drainage parameters, analysis of geomechanical processes, development of schemes for modeling by the finite element method, substantiation of methodological approaches for conducting experimental research into the rock pressure manifestations in extraction working, taking into account existing tendencies of the influence of stoping face advance velocity. Research results. The views on the mechanism of the stratified mass texture transformations of weak rocks have been developed during the study of the optimal extraction site gas-drainage parameters. The deformation development schemes have been constructed for any layer of the main roof behind the area of longwall face conjugation with the extraction working, displacement of coal-overlaying formation rocks along and across the extraction site with the location of gas-drainage wells. Based on the conducted research, recommendations on the rational location of gas-drainage wells have been obtained. Scientific novelty. The main characteristics of the weakly metamorphosed rock displacement process in the area of stope operations are studied in a spatial formulation, and the mechanism of the influence of geomechanical-technological factors on the expedient location parameters of gas-drainage wells behind the longwall face is represented on the relevant schemes. Practical value. The reliability of the proposed location parameters for gas-drainage wells behind the longwall face in the conditions of weakly metamorphosed rocks of the Western Donbas has been analyzed, taking into account the stoping face advance increased velocities.The conclusions drawn on the basis of rock displacement tendencies in the coal-overlaying formation are summarized in the schemes for identifying the mechanism of rock mass deformation near the area of stope operations.