Search Results (10)

Increasing concern over climate change has made Carbon Capture and Storage (CCS) an important tool. Operators use deep geologic reservoirs as a form of favorable geological storage for long-term CO₂ sequestration. However, the success of CCS hinges on the integrity of wells penetrating these formations, particularly legacy wells, which often exhibit significant uncertainties regarding cement tops in the annular space between the casing and formation, especially around or below the primary seal. Misalignment of cement plugs with the primary seal increases the risk of CO₂ migrating beyond the seal, potentially creating pathways for fluid flow into upper formations, including underground sources of drinking water (USDW). These wells may not be leaking but might fail to meet the legal requirements of some federal and state agencies such as the Environmental Protection Agency (EPA), Railroad Commission of Texas (RRC), California CalGEM, and Pennsylvania DEP. This review evaluates the impact of CO₂ exposure on cement and casing integrity including the fluid transport mechanisms, fracture behaviors, and operational stresses such as cyclic loading. Findings revealed that slow fluid circulation and confining pressure, primarily from overburden stress, promote self-sealing through mineral precipitation and elastic crack closure, enhancing well integrity. Sustained casing pressure can be a good indicator of well integrity status. While full-physics models provide accurate leakage prediction, surrogate models offer faster results as risk assessment tools. Comprehensive data collection on wellbore conditions, cement and casing properties, and environmental factors is essential to enhance predictive models, refine risk assessments, and develop effective remediation strategies for the long-term success of CCS projects. Full article

Writing proficiency is important for academic and professional success, yet only one-third of US students write at proficient levels. While Self-Regulated Strategy Development (SRSD) has shown effectiveness across different populations, few studies have examined its application in elementary social studies contexts. This study investigated the implementation of STOP DARE+, an SRSD-based writing intervention incorporating reading from social studies source texts and perspective-taking, in a fourth-grade social studies classroom studying the Underground Railroad. The intervention was delivered across 11 sessions to 12 students with diverse learning needs. Writing quality was assessed using the newly developed Multidimensional Spectrum of Holistic Writing Quality scoring tool, alongside genre elements and text production measures. Social validity was evaluated through the Teacher-Informed Perspectives Snapshot (TIPS), a new repeated-measures tool, combined with interviews and student focus groups. Results showed significant improvements in all writing measures with large effect sizes. Students and teachers reported strong positive perceptions of the intervention’s effectiveness and meaningfulness, with students particularly emphasizing the importance of perspective-taking for both academic and social development. The findings suggest that integrating SRSD-based writing instruction with social studies content can enhance both writing skills and critical thinking while fostering deeper engagement with historical events and social justice themes. Full article

The logistics transportation system is critical to the United States economy. Underground Logistics Transportation (ULT) is a class of automated transportation systems in which vehicles carry freight through pipelines and tunnels between terminals. Being able to use a part of the underground space of existing highways will greatly facilitate the construction of such pipelines and tunnels and reduce their construction costs. Underground Logistics Transportation (ULT) could be the answer to make freight transport more sustainable and competitive. Texas highways and railroads are expected to increase by nearly 207% from 2003 to 2030. Truck tonnage will grow by 251%, while rail tonnage is forecasted to increase 118%. The number of trucks carrying NAFTA goods will increase by 263%, and the number of rail units will grow by 195%. This will have a profound impact on the highway and rail systems. The objective of this paper is to present requirements and operational components for three types of ULT lines: standard shipping containers, a standard crate size, and a standard pallet size. This study examines the use of ULT as a mode of underground transportation with the help of three case studies. This research shows that ULT is financially viable, feasible, greener, cost effective, and can become an important part of intermodal freight mobility. Full article

Research on the excavation mechanical properties of underpass tunnels has already had certain results, but only a few of them consider the effects of dynamic and static loads on the excavation mechanical properties of underground tunnels at the same time; particularly, there is a lack of research investigating double-line highway tunnels with angled underpasses of existing railway tunnels. In this paper, based on the tunnel project of the new double-line Shiqian Highway Tunnel passing under the Hurong Railway with an oblique angle, based on the method of over-advance geological prediction and investigations into the palm face surrounding the rock, the rock degradation caused by dynamic and static loads is quantified using the perturbation system. Additionally, the mechanical parameters of the rock under the influence of dynamic and static load coupling in the influence area of the cross-tunneling project are determined using the Hoek–Brown criterion, and the mechanical characteristics of the excavation of a tunnel under the double-lane highway tunnel passing under the existing railroad are constructed with the mechanical characteristics of the double-lane highway tunnel, taking into consideration the influence of the dynamic and static load coupling in a three-dimensional model. The results show that, in line with the new tunnel rock movement law for the top of the arch sinking, the bottom plate bulging, the side wall outward movement, the height and width of the arch, and the bottom plate arch show an increase with the tunnel excavation, while the side wall rock displacement effect is smaller; the left and right line tunnel disturbed area of the rule of change is similar; the existing tunnel bottom plate displacement is larger than the top plate and the left and right side wall, under the influence of the excavation time step. Typical profile point displacement is mainly determined by the distance from the excavation surface; von Mises stress extremes are observed in the top plate and side walls of the existing tunnel, which occur in the tunnel structure, and there are unloading and pressure-bearing zones in the bottom plate; the new tunnel has the same rock disturbance angle under the four calculation conditions and, based on the displacement control criterion, the excavation method is preferred and the upper and lower step blasting excavation method is recommended. Full article

As rail transportation continues to advance, it provides significant convenience to the public. However, the environmental vibration and noise generated during its operation have become major concerns for residents living near rail lines. In response to these concerns, the “Law on the Prevention and Control of Noise Pollution” was promulgated in China, bringing attention to this issue within the rail transportation sector. This review summarizes the regular features observed in environmental vibration and secondary structural noise tests on different sections, including embankment sections, bridge sections, underground railroads and vehicle sections. Furthermore, it introduces several physical models utilized in the study of environmental vibration and secondary structural noise, focusing on three key aspects: excitation sources, propagation paths and the modelling of building structures. This paper also explores the introduction of data-driven models related to big data and artificial intelligence to enhance the accuracy and efficiency of research in this field and provides an overview of commonly used measures to control train-induced environmental vibrations and secondary noise in buildings. These measures are discussed in terms of excitation sources, propagation paths, and receivers, offering insights into effective strategies for mitigating the impact of rail transportation on nearby residents. Finally, this study highlights the primary findings and offers pertinent recommendations. These recommendations include considerations regarding both laboratory and on-site testing procedures, challenges associated with the deployment of data-driven models and key parameters for designing and utilizing low-stiffness fasteners. Full article

Black creators who tell Harriet Tubman’s story engage in an ongoing rhetorical battle over historical memory with regard to slavery and the Civil War. This essay examines the challenges Tubman’s story poses to a Lost Cause narrative that took root in the nineteenth-century and manifests in the work of celebrated children’s author Robert Lawson. Reading Ann Petry’s YA biography Harriet Tubman: Conductor on the Underground Railroad (1955), Jacob Lawrence’s picture book Harriet and the Promised Land (1968), and Kasi Lemmons’ film Harriet (2019) together, and within the context of Lawson’s award-winning They Were Strong and Good (1940) and his historical primer Watchwords of Liberty: A Pageantry of American Quotations (1943) offers an opportunity to assess the rhetorical firepower of creative work about a historical figure who continues to fascinate people of all ages. Such reading also underscores the extent to which the apartheid in and of children’s literature limits the imaginations of critics, thereby hindering efforts to promote social justice. Full article

This essay analyses the role played by okra in The Underground Railroad, together with how it functions in relation to the soil that sustains it and which allows it to grow. I argue that okra represents an otherwise lost African past for both protagonist Cora and for the show in general and that this transplanted plant, similar to the transplanted Africans who endured the Middle Passage on the way to ‘New World’ slave plantations, survives by going through ‘black holes’, something that is not only linked poetically to the established trope of the otherwise absent Black mother but which also finds support from physics, where wormholes (similar to the holes created by worms in the soil) take us through black holes and into new worlds, realities or dimensions. This is reflected in Jenkins’s series (as well as Whitehead’s novel) by the titular Underground Railroad itself, which sees Cora and others disappear underground only to reappear in new states (the show travels from Georgia to South Carolina to North Carolina to Tennessee to Indiana and so on), as well as specifically in the show through the formal properties of the audio-visual (cinematic/televisual) medium, which, with its cuts and movements, similarly keeps shifting through space and time in a nonlinear but generative fashion. Finally, I suggest that we cannot philosophise the plant or the medium of film (or television or streaming media) without philosophising race, with The Underground Railroad serving as a means for bringing together plants and plantations, soil and wormholes and Blackness and black holes, which, collectively and playfully, I group under the umbrella term ‘black (w)hole foods’. Full article

In this study, the factors influencing the choice of the type of urban railroad transportation in the metropolitan areas of Korea were analyzed. As the populations of metropolitan areas are expanding, the importance of rail transportation, which has a high travel reliability in terms of travel time, has increased, and various types of railroad systems have emerged accordingly. This study was focused on the choice behavior of travelers on local and express trains that use the same track and differ only in the number of stations and operating times. To compare the choice behavior of travelers between local and express trains, factors such as the waiting time on the platform and the in-car travel time were considered. We also investigated the system choice behavior for an existing express subway and high-speed rail trains in tunnels at a great depth in terms of horizontal access time (walking), vertical access time, in-vehicle travel time, and travel fare. For a high-speed rail built underground at a great depth of 50 m, the stated preference survey was designed, and data were collected in consideration of the Great Train Express being promoted in the Seoul metropolitan area by the Korean government. The results of this study are expected to be considered important data for improving the rail system design from the user’s perspective to increase the demand for urban rail transportation in metropolitan areas. Full article

The aim of this study was to investigate the causes of the evolution of atmospheric dust composition in an open-to-public subterranean site (UNESCO-recognized historic mine) at increasing distances from the air intake. The role of the components imported with atmospheric air from the surface was compared with natural and anthropogenic sources of dust from inside the mine. Samples of deposited dust were directly collected from flat surfaces at 11 carefully selected sites. The morphological, mineralogical, and chemical characteristics were obtained using scanning electron microscopy (SEM), X-ray diffraction (XRD), and inductively coupled plasma spectroscopy (ICP). The study showed that the air in the underground salt mine was free of pollutants present in the ambient air on the surface. Most of the components sucked into the mine by the ventilation system from the surface (regular dust, particulate matter, gaseous pollutants, biogenic particles, etc.) underwent quick and instantaneous sedimentation in the close vicinity of the air inlet to the mine. The dust settled in the mine interior primarily consisted of natural geogenic particles, locally derived from the weathering of the host rock (halite, anhydrite, and aluminosilicates). This was confirmed by low values of enrichment factors (EF) calculated for minor and trace elements. Only one site, due to the tourist railroad and the associated local intensive tourist traffic, represented the anthropogenic sources of elevated concentrations of ferruginous particles and accompanied metals (P, Cr, Mn, Co, Ni, Cu, As, Mo, Cd, Sn, Sb, Pb, and W). The gravitational deposition of pollutants from these sources limits the effects of the emissions to the local range. The used methodology and the results are universal and might also apply to other mines, caves, or underground installations used for museums, tourists, or speleotherapeutic purposes. Full article

In 2016 and 2017, Colson Whitehead’s The Underground Railroad and Jesmyn Ward’s Sing, Unburied, Sing both won the National Book Award for fiction, the first time that two African-American writers have won the award in consecutive years. This article argues that both novels invoke African-based spirituality in order to create literary sites of resistance both within the narrative of the respective novels, but also within American culture at large. By drawing on a tradition of authors using African-based spiritual practices, particularly Voodoo, hoodoo, conjure and rootwork, Whitehead and Ward enter and engage in a tradition of African American protest literature based on African spiritual traditions, and use these traditions variously, both as a tie to an originary African identity, but also as protection and a locus of resistance to an oppressive society. That the characters within the novels engage in African spiritual traditions as a means of locating a sense of “home” within an oppressive white world, despite the novels being set centuries apart, shows that these traditions provide a possibility for empowerment and protest and can act as a means for contemporary readers to address their own political and social concerns. Full article