Intermediate Locations Research Articles

Utilizing gene expression programming strategies for estimating relative uplift pressure head at key-points beneath straight horizontal aprons

ABSTRACT Seepage flow beneath the hydraulic structures creates uplift pressure on its floor that affects the performance of these structures. Prior studies have assumed that the cutoff wall is solid, however, perfect impermeability does not occur in the real world. This investigation yields an acceptable model for computing the relative uplift pressure at key points created by a vertical cutoff wall positioned at different locations (at the upstream end, at an intermediate location, and at the downstream end) underneath hydraulic structures. A series of numerical models based on the finite element method (FEM) were developed. With the generated data, Gene Expression Programming (GEP) is used to calculate the relative uplift pressure. The GEP model yielded high values of R 2, R, KGE, and NSE, and low values of MAE, RE%, and RMSE. Additionally, diagrams that allowed better estimation of relative uplift pressure were created. The NSE and KGE indices extracted using the GEP model are in a range of 0.75 < NSE ≤ 1 and 0.7 < KGE ≤ 1 whereas the RE% for the proposed models for each of the key points is less than 7.5%.

The research focus and frontiers in surgical treatment of essential tremor.

Essential tremor (ET) is one of the most prevalent neurodegenerative disorders, with surgery serving as the principal treatment option. This paper presents a bibliometric analysis of research in the field of ET surgery from 2004 to 2024, aiming to identify current research hotspots and inform future research directions. This study employs CiteSpace to analyze publication trends, countries/institutions, authors, keywords, and co-cited references in ET surgery, using the Web of Science core database from 2004 to 2024 to delineate the research pathways. A total of 1,362 publications were included in this study. The number of publications has shown steady growth over the analyzed period from 2004 to 2024. Research in this field was carried out in 58 countries and by 371 institutions. The United States had the highest volume of publications, with the University of California System identified as the most prolific institution. Dr. Michael S. Okun from the University of Florida was the most prolific author, also based in the United States. This study identified 879 keywords, with significant citation bursts noted in areas such as the caudal zona incerta, ventral intermediate nucleus, location, and MR-guided focused ultrasound. Among the top ten highly cited articles, five pertained to MR-guided focused ultrasound thalamotomy, two addressed localization techniques, and one focused on surgical targets. This study employs comprehensive bibliometric and visualization analyses to elucidate the evolution of research and identify emerging hotspots. The identified hotspots are as follows: First, deep brain stimulation (DBS), the most advanced technology in ET surgery, has room for improvement, especially in neuromodulation automation. Second, MR-guided focused ultrasound thalamotomy is a new surgical approach that requires further research on efficacy, safety, and side effect management. Third, novel surgical targets have demonstrated some efficacy, yet further research is essential to validate their effectiveness and safety. Lastly, localization techniques are fundamental to ET surgery, with ongoing efforts directed towards achieving more precise, individualized, and intelligent localization.

Affordability and accessibility of condominium housing in urban Ethiopia using a combined transportation and housing cost (CHT) index model: implication for sustainable urban infrastructure, policy and development

ABSTRACT Condominium housing is a critical housing option, but its affordability measures continue to be debatable. This study examined the mutual effect of housing & transportation monthly expenses on housing location affordability and accessibility, considering three comparable locations- inner-city, intermediate, and outer-city condominium locations in Addis Ababa, Ethiopia. 1152 condominium residents were surveyed to assess urban housing location affordability using the combined H+T affordability index, GIS, one-way ANOVA, and Logit model. Housing affordability is diversified in the city, distance to CBD & transport are significant factor. Outer-city and intermediate neighbourhoods are unaffordable & inaccessible, with 55% and 48% index, respectively. Outer-city residents and lower-incomers face higher financial burdens. Nevertheless, inner-city is affordable & accessible, and residents enjoy better proximity to services. It contributes insights to enhance literature and debates on the model. H+T index provides up-to-date understanding and informs policymaking for innovative, smart, and sustainable, location-sensitive, integrated, and pro-poor policies.

Inhomogeneous Skin Formation and Its Effect on the Tensile Behavior of a High Pressure Die Cast Recycled Secondary AlSi10MnMg(Fe) Alloy

The current study investigated the microstructure evolution, mechanical properties, and fracture behavior of a high pressure die cast (HPDC) novel secondary alloy. The as-cast microstructure comprised (i) Primary α-Al, (ii) α-Al15(FeMn)3Si2 intermetallics, and (iii) Al–Si eutectics. The microstructure starting from the surface through the depth of the HPDC casting consisted of (i) fine-grained skin at surface, (ii) increased Al–Si eutectics at intermediate location, and (iii) coarse α-Al dendrites at center. Accordingly, the hardness increased from skin to the intermediate section and then decreased toward the center of the casting. The formation of skin layer was highly discontinuous, which was attributed to the complicated fluid flow pattern inside the die cavity. The skin layer indicated to slightly improve the strength of the HPDC alloy; however, it restricted the ductility of the material with a large variation. Such ductility behavior resulted from a fracture mechanism triggered by the inhomogeneous skin because of its poor bonding with the adjacent matrix. Even though the secondary alloy contained casting defects and α-Al15(FeMn)3Si2 intermetallics that are known to be driving factors for the fracture in such materials, the effects from the inhomogeneous skin turned out to be predominant in the current study.

Sterile Intraocular Inflammation Associated With Faricimab

Randomized clinical trials are conducted to establish both drug safety and efficacy. However, evidence of adverse events associated with these drugs in the clinical practice setting can be of value at generating hypotheses regarding less common safety issues, even if causality cannot be determined. To present and analyze cases of intraocular inflammation associated with faricimab therapy in patients referred to a single European institution. This was a review starting in April of 2024 of an observational case series. Patients were from a single academic-based tertiary referral center in Switzerland. Included in the analysis were patients referred for intraocular inflammation soon after receiving a faricimab intravitreal injection between June 1, 2022, and March 5, 2024. Faricimab, 6 mg (0.05 mL of a 120-mg/mL solution), administrated for neovascular age-related macular degeneration or diabetic macular edema. The systemic and ocular histories and imaging data available were reviewed. The following were evaluated: visual acuity measured with habitual correction using the Early Treatment of Diabetic Retinopathy Study charts before and after the event; intraocular pressure; patient symptoms; anterior, intermediate, or posterior location of the intraocular inflammation; and the presence of retinal vasculitis. Multimodal imaging including color fundus photographs, fluorescein angiograms, indocyanine green angiograms, and optical coherence tomography were reviewed. A total of 12 eyes from 7 patients (mean [SD] age, 73.3 [16.7] years; 4 female [57.1%]) over 22 months were identified as having noninfectious intraocular inflammation after intravitreal faricimab injections. Among these cases, in 2 eyes, retinal vasculitis was present together with anterior and posterior inflammation. One of the 2 eyes had an occlusive form of vasculitis of the arteries and veins, leading to subsequent macular capillary nonperfusion and clinically relevant irreversible vision deterioration from 20/80 to 20/2000. The remaining eyes were characterized by moderate anterior segment inflammation without substantial vision changes. The intraocular inflammation event occurred after a median (IQR) of 3.5 (2.0-4.3) faricimab injections. The median (IQR) interval between the last faricimab injection and the diagnosis of inflammation was 28 (24-38) days. Increased intraocular pressure of 30 mm Hg or higher was found in 3 eyes. This case series highlights the occurrence of rare, but potentially severe, intraocular inflammation associated with faricimab therapy. Although these findings do not prove causality and can only generate hypotheses for future investigations, these results suggest the importance of continuous surveillance and monitoring for patients undergoing faricimab therapy to promptly identify and manage potential adverse events.

Streamwise energy-transfer mechanisms in zero- and adverse-pressure-gradient turbulent boundary layers

The present study investigates streamwise ( $\overline {u^2}$ ) energy-transfer mechanisms in the inner and outer regions of turbulent boundary layers (TBLs). Particular focus is placed on the $\overline {u^2}$ production, its inter-component and wall-normal transport as well as dissipation, all of which become statistically significant in the outer region with increasing friction Reynolds number ( $Re_{\tau }$ ). These properties are analysed using published data sets of zero, weak and moderately strong adverse-pressure-gradient (APG) TBLs across a decade of $Re_{\tau }$ , revealing similarity in energy-transfer pathways for all these TBLs. It is found that both the inner and outer peaks of $\overline {u^2}$ are always associated with local maxima in the $\overline {u^2}$ production and its inter-component transport, and the regions below/above each of these peaks are always dominated by wall-ward/away-from-wall transport of $\overline {u^2}$ , thereby classifying the $\overline {u^2}$ profiles into four distinct regimes. This classification reveals existence of phenomenologically similar energy-transfer mechanisms in the ‘inner’ and ‘outer’ regions of moderately strong APG TBLs, which meet at an intermediate location coinciding with the minimum in $\overline {u^2}$ profiles. Conditional averaging suggests existence of similar phenomena even in low $Re_{\tau }$ canonical and/or weak APG TBLs, albeit with the outer-region mechanisms weaker than those in the inner region. This explains the absence of their $\overline {u^2}$ outer peak and the dominance of $\overline {u^2}$ wall-normal transport away from the wall, which potentially originates from the inner region. Given that the wall-ward/away-from-wall transport of $\overline {u^2}$ is governed by the $Q_4$ (sweeps)/ $Q_2$ (ejections) quadrants of the Reynolds shear stress, it is argued that the emergence of the $\overline {u^2}$ outer peak corresponds with the statistical dominance of $Q_4$ events in the outer region. Besides unravelling the dynamical significance of $Q_2$ and $Q_4$ events in the outer region of TBLs, the present analysis also proposes new phenomenological arguments for testing on canonical wall-turbulence data at very high $Re_{\tau }$ .

Shifts in light availability driven by dieback across a marsh‐forest gradient

AbstractEcological zonation in coastal forests is driven by sea level rise and storm‐surge events. Mature trees that can survive moderately saline conditions show signs of stress when soil salinity increases above its tolerance levels. As leaf burn, foliar damage, and defoliation reduce tree canopy cover, light gaps form within the crown. At the forest‐marsh edge, canopy cover loss is most severe; trunks of dead trees without canopies form “ghost forests.” Canopy thinning and light from the edge alter conditions for understory vegetation, promoting the growth of shrubs and facilitating establishment and spread of invasive species that were previously limited by light competition. In this research, we present an analysis of illuminance and temperature in a coastal forest transitioning to a salt marsh. Light sensors above the ground surface were used to measure light attenuation of trees and understory vegetation and to observe the effect of reduced canopies at the forest‐marsh edge. Farther from the marsh, where salinity is lower and trees are healthy, dense canopies attenuate light. We estimate that during the growing season, tree canopies intercept 50% of illuminance on average. Closer to the marsh, canopy thinning, and tree death allow greater light penetration from above, as well as from the adjacent marsh. These illuminance values are further increased by light penetration from the forest‐marsh edge (edge effect). Here, higher illuminance may permit Phragmites australis expansion. At intermediate locations, trees intercept between 32% and 49% of light and the understory shrub Morella cerifera intercepts a further 45% of penetrating light based on comparisons of illuminance above and below shrub canopies. Light penetration from the edge can also be felt. The presence of M. cerifera reduces the air temperature close to the soil surface, creating a cooler summer microclimate. The tree health state is reflected in the canopy size. The canopy patterns and the edge effect are responsible for light availability distribution along forest‐marsh gradients, consequently affecting the understory vegetation biomass. We conclude that during forest retreat driven by sea level rise, tree dieback increases light availability favoring the temporary encroachment of Ph. australis and M. cerifera in the understory.

Wavefront sensing with a gradient phase filter

Wavefront sensors have now become core components in the fields of metrology of optical systems, biomedical optics, and adaptive optics systems for astronomy. However, none of the designs used or proposed so far achieve simultaneously a high spatial resolution at the pupil of the tested optics and absolute measurement accuracy comparable to those of modern laser-interferometers. This paper presents an improved wavefront sensor concept that reaches both previous goals. This device named Crossed-sine phase sensor (CSPS) is based on a fully transparent gradient phase filter (GPF) placed at an intermediate location between the virtual pupil and image planes of the tested optics. The theoretical principle of the sensor is described in Fourier optics formalism. Numerical simulations confirm that a measurement accuracy of λ/100 RMS is achievable. The CSPS also offers the advantages of being quasi-achromatic and working on spatially or spectrally extended, natural or artificial light sources.

When spatial attention cannot be divided: Quadrantic enhancement of early visual processing across task–relevant and irrelevant locations

Abstract Spatial attention enables us to select regions of space and prioritize visual processing at the attended locations. Previous research has shown that spatial attention can be flexibly tuned to broader or narrower regions in space, and in some cases be split amongst multiple locations. Here, we investigate how attentional resources are distributed within a visual quadrant when participants are instructed to either focus attention narrowly, broadly, or split attention among two non-contiguous locations. Using a combination of behavior and steady-state visual-evoked potentials (SSVEP), the oscillatory response of the visual cortex to incoming flickering stimuli, we find clear evidence for ineffective splitting of spatial attention within a visual quadrant. Importantly, by assessing visual-cortical processing across locations at a high spatial resolution (by flickering nearby locations at distinct frequencies), our results reveal that attention was distributed in the exact same manner regardless of whether participants were instructed to attend broadly across a large region of space, or divide attention amongst two non-contiguous locations: In both cases, the intermediate location showed the strongest boost in visual-cortical processing, no matter whether it was the center of the attended region (broad-focus condition), or the uncued, to-be-ignored location (split-focus condition). Thus, the present study provides strong evidence that when trying to attend to multiple separate locations within a visual quadrant, sustained attention inadvertently enhances visual processing at the intermediate location even when it is detrimental to task performance.

DNA choreography: correlating mobility and organization of DNA across different resolutions from loops to chromosomes

The dynamics of DNA in the cell nucleus plays a role in cellular processes and fates but the interplay of DNA mobility with the hierarchical levels of DNA organization is still underexplored. Here, we made use of DNA replication to directly label genomic DNA in an unbiased genome-wide manner. This was followed by live-cell time-lapse microscopy of the labeled DNA combining imaging at different resolutions levels simultaneously and allowing one to trace DNA motion across organization levels within the same cells. Quantification of the labeled DNA segments at different microscopic resolution levels revealed sizes comparable to the ones reported for DNA loops using 3D super-resolution microscopy, topologically associated domains (TAD) using 3D widefield microscopy, and also entire chromosomes. By employing advanced chromatin tracking and image registration, we discovered that DNA exhibited higher mobility at the individual loop level compared to the TAD level and even less at the chromosome level. Additionally, our findings indicate that chromatin movement, regardless of the resolution, slowed down during the S phase of the cell cycle compared to the G1/G2 phases. Furthermore, we found that a fraction of DNA loops and TADs exhibited directed movement with the majority depicting constrained movement. Our data also indicated spatial mobility differences with DNA loops and TADs at the nuclear periphery and the nuclear interior exhibiting lower velocity and radius of gyration than the intermediate locations. On the basis of these insights, we propose that there is a link between DNA mobility and its organizational structure including spatial distribution, which impacts cellular processes.

Searching for the fine particulate matter (PM 2.5) pollutant emission source using a drone

In this research, we propose a method with three search algorithms, namely Greedy, Dynamic, and Hybrid, to exploit the ability of a drone to efficiently and accurately locate air pollution (i.e., particulate matter) emission sources. Currently, most of the existing stationed environment sensor systems can provide continuous monitoring information of air quality such as PM 2.5 (Particulate Metter 2.5) or CO2 (carbon dioxide) but are unable to pinpoint the location of the emission source. The proposed method utilizes the PM2.5 concentration information provided by the existing sensing system to initialize the search plan by limiting a search area. Based on the initial sensing information, a drone with an onboard air quality sensor will adjust its searching direction and distance to an intermediate point. After an intermediate location point is reached, the drone will pause and sense the PM2.5 concentration at the current location. Next, the drone continues to adjust the search path with its searching direction and distance based on the sensed PM 2.5 concentration level until the emission source is located. Utilizing the information provided by both an existing sensing system and an onboard sensor, the drone is able to make correct decisions when searching for pollution sources. In the experiments, three proposed algorithms and two common search methods are compared under different settings. Experiment results showed our proposed method is able to achieve a location estimation error below 2 m within 20 min.

Exploring Trauma Patterns and Contributing Factors With Slim Straight Electrode Array After Cochlear Implantation.

To assess trauma patterns associated with the insertion of lateral wall electrode arrays. The study focused on 3 categories-scala tympani (ST), intermediate, and scala vestibuli (SV)-to identify traumatic patterns and contributing factors. Retrospective study. Data from 106 cochlear implant recipients at a tertiary otologic center. Demographic and surgical data were collected from recipients who underwent cochlear implantation manually and with RobOtol®. Measurements included cochlear dimensions, angular depth of insertion, and position of the first electrode. Three-dimensional reconstructions were used to analyze the electrode array location relative to the basilar membrane, categorized into ST, intermediate, and SV electrodes. Nontraumatic insertion was defined as all electrodes in the ST, while traumatic insertions had 1 or more electrodes in intermediate or SV locations. Out of 106 cases, 44% had nontraumatic and 56% had traumatic insertions. Demographic and surgical characteristics showed no association with traumatic insertions. A deeper position of the first electrode, relative to the round window, was associated with traumatic insertions (P = .03). Three trauma patterns were observed: distal (facing the apical electrodes), proximal (facing the middle electrodes around 180°), and distal/proximal. This study considers the intermediate position which could be associated with basilar membrane lesions. Risk zones for intracochlear trauma with lateral wall arrays were identified distally and proximally. Traumatic insertions were independently linked to deeper array placement. Future studies should explore whether gentler insertion, without insisting on further electrode array insertion depth, could reduce the trauma during cochlear implantation.

A cyst-forming coccidian with large geographical range infecting forest and commensal rodents: Sarcocystis muricoelognathis sp. nov.

BackgroundThe geographic distribution and host-parasite interaction networks of Sarcocystis spp. in small mammals in eastern Asia remain incompletely known.MethodsExperimental infections, morphological and molecular characterizations were used for discrimination of a new Sarcocystis species isolated from colubrid snakes and small mammals collected in Thailand, Borneo and China.ResultsWe identified a new species, Sarcocystis muricoelognathis sp. nov., that features a relatively wide geographic distribution and infects both commensal and forest-inhabiting intermediate hosts. Sarcocystis sporocysts collected from rat snakes (Coelognathus radiatus, C. flavolineatus) in Thailand induced development of sarcocysts in experimental SD rats showing a type 10a cyst wall ultrastructure that was identical with those found in Rattus norvegicus from China and the forest rat Maxomys whiteheadi in Borneo. Its cystozoites had equal sizes in all intermediate hosts and locations, while sporocysts and cystozoites were distinct from other Sarcocystis species. Partial 28S rRNA sequences of S. muricoelognathis from M. whiteheadi were largely identical to those from R. norvegicus in China but distinct from newly sequenced Sarcocystiszuoi. The phylogeny of the nuclear 18S rRNA gene placed S. muricoelognathis within the so-called S. zuoi complex, including Sarcocystisattenuati, S. kani, S. scandentiborneensis and S. zuoi, while the latter clustered with the new species. However, the phylogeny of the ITS1-region confirmed the distinction between S. muricoelognathis and S. zuoi. Moreover, all three gene trees suggested that an isolate previously addressed as S. zuoi from Thailand (KU341120) is conspecific with S. muricoelognathis. Partial mitochondrial cox1 sequences of S. muricoelognathis were almost identical with those from other members of the group suggesting a shared, recent ancestry. Additionally, we isolated two partial 28S rRNA Sarcocystis sequences from Low’s squirrel Sundasciurus lowii that clustered with those of S. scandentiborneensis from treeshews.ConclusionsOur results provide strong evidence of broad geographic distributions of rodent-associated Sarcocystis and host shifts between commensal and forest small mammal species, even if the known host associations remain likely only snapshots of the true associations.Graphical

Two-stage problems of optimal location and distribution of the humanitarian logistics system’s structural subdivisions

Purpose. To ensure the rational organization of the evacuation of people from a region affected by an emergency by developing a mathematical and algorithmic toolkit that will allow for the early distribution of transport and material resources, maximizing coverage of the affected areas while minimizing evacuation time. Methodology. System analysis of evacuation processes; mathematical modeling, the theory of continuous problems of optimal partitioning of sets, non-differentiable optimization. Findings. The object of the study is the two-stage evacuation logistic processes that occur when serving the population of areas affected by emergencies of a natural or technogenic nature. The research considers the possibility of optimally distributing human flows within the transportation system, the structural subdivisions of which are first-stage centers (first aid stations that carry out the reception of citizens from areas affected by the disaster) and second-stage centers (specialized units of the emergency aid system that provide further services to the evacuated population). The proposed mathematical model deals with the problem of optimally partitioning a continuous set with the placement of subset centers and additional connections. Methods for its solution have been described. We demonstrate the versatility of these models, as they can be used to describe logistic evacuation processes, organize assembly points, intermediate locations, evacuation reception points, and those providing primary assistance to the affected population. We calculate the appropriate number of essential products and deliver them from existing warehouses through distribution centers to the affected areas. Originality. As preventive measures to increase the level of population safety during an emergency, we consider the optimal placement of rescue facilities and the zoning of the territory to distribute evacuation traffic. We also address the problem of the optimal distribution of human flows in the transport and logistics system. Practical value. The presented models, methods, and algorithms enable the solution of many practical problems related to the development of preventive measures and the planning of rescue operations to ensure the population’s safety in case of emergencies. The theoretical results obtained are translated into specific recommendations that can be utilized when addressing logistical problems related to the organization of primary evacuation of the population from affected areas and their subsequent transportation to safer locations for further assistance.

Self-supervised multicontrast super-resolution for diffusion-weighted prostate MRI.

This study addresses the challenge of low resolution and signal-to-noise ratio (SNR) in diffusion-weighted images (DWI), which are pivotal for cancer detection. Traditional methods increase SNR at high b-values through multiple acquisitions, but this results in diminished image resolution due to motion-induced variations. Our research aims to enhance spatial resolution by exploiting the global structure within multicontrast DWI scans and millimetric motion between acquisitions. We introduce a novel approach employing a "Perturbation Network" to learn subvoxel-size motions between scans, trained jointly with an implicit neural representation (INR) network. INR encodes the DWI as a continuous volumetric function, treating voxel intensities of low-resolution acquisitions as discrete samples. By evaluating this function with a finer grid, our model predicts higher-resolution signal intensities for intermediate voxel locations. The Perturbation Network's motion-correction efficacy was validated through experiments on biological phantoms and in vivo prostate scans. Quantitative analyses revealed significantly higher structural similarity measures of super-resolution images to ground truth high-resolution images compared to high-order interpolation (p 0.005). In blind qualitative experiments, of super-resolution images were assessed to have superior diagnostic quality compared to interpolated images. High-resolution details in DWI can be obtained without the need for high-resolution training data. One notable advantage of the proposed method is that it does not require a super-resolution training set. This is important in clinical practice because the proposed method can easily be adapted to images with different scanner settings or body parts, whereas the supervised methods do not offer such an option.

Optimising product swaps in an urban retail network with uncertainty

City Logistics aims to achieve higher levels of consolidation in vehicles that typically requires exchanging loads at intermediate locations. Swapping goods between retail stores in urban areas due to stock shortages is a common problem arising in for example, omni-channel logistics. This study develops a two-stage stochastic program for designing a product swap network. The upper stage of the program deals with the strategic decision of locating transhipment nodes, while the lower stage finds the optimal operational vehicle routing solution. Uncertainties in demand, traffic conditions, and vehicle loading efficiency are considered. Numerical studies evaluate various solution procedures and demonstrate the importance of considering stochasticity and the value of the two-stage model.

Two-Echelon Electric Vehicle Routing Problem with Battery Swap Stations on Real Network

This research develops an advanced optimization framework for two-echelon electric vehicle routing problems. It tackles complex road networks, time windows, split deliveries, and battery swapping stations. By integrating optimal intermediate depot locations with efficient routing, the multi-objective model, solved using the epsilon constraints method in GAMS, addresses urban delivery challenges. The model manages larger goods volumes through split deliveries and enhances urban distribution logistics with electric vehicles, balancing sustainability and economic viability. Key features include managing electric vehicle routing limitations, ensuring timely deliveries, and optimizing split deliveries to reduce trips and congestion. The multi-objective approach minimizes travel distance, energy consumption, and costs while maximizing service levels. Strategically locating depots reduces travel distances and enhances service area coverage, improving network responsiveness. In conclusion, this research offers a holistic approach to urban logistics with electric vehicles, enhancing operational efficiency and contributing to environmental and economic goals. It provides valuable tools for decision-makers aiming to improve urban distribution networks.

Understanding the Role of Cracks in Active Oxygen Species Formation during Oxygen Evolution Reaction

Understanding the formation and location of catalytic intermediates is crucial for unraveling the mechanism of oxygen evolution reaction (OER), a key process in electrochemical water splitting. Despite the availability of various in-situ and ex-situ characterization methods, the formation and location of intermediates remain elusive, hindering the development of more efficient electrocatalysts. In this work, we discovered a stable static active oxygen species formed during the chemical oxidation of cobalt hydroxide flakes, providing a unique opportunity to probe the intermediates involved in OER. We are able to monitor the equilibrium conversion between stable peroxo structure and superoxo radical via EPR and Raman test, shedding light on the nature of the active oxygen species. In addition, CoOOH flakes with cracks were synthesized via controlled chemical oxidation, enabling the investigation of the role of crack/edge structures in the electrocatalytic activity. Statistical regression analysis combining morphological features, electrochemical performance, and Raman spectroscopy confirmed a strong correlation between morphology evolution, OER activity, and active oxygen species, highlighting the importance of controlling the morphology of electrocatalysts for enhancing their performance. Therefore, we propose that the source of active oxygen intermediates can be attributed to the presence of crack/edge structures. The crack-rich CoOOH exhibit significantly higher current density at a lower overpotential, providing a new direction for the design of efficient water oxidation electrocatalysts. Overall, this work offers important insights into the mechanism of OER and provides a basis for the development of more efficient and sustainable electrocatalysts for energy conversion and storage.

Influence of a Subsidiary Weir on the Stability of a Main Structure Built on a Finite Stratum

Some dams globally have negatively affected downstream structures. Constructing subsidiary weirs may solve this problem. This novel study focuses on investigating the parameters of seepage beneath the original structure and the proposed subsidiary weir. Conformal mapping and finite element methods are used for the analysis. The proposed subsidiary weir consists of a sloping central apron, flat aprons on both the downstream and upstream ends, and upstream and downstream sheet piles of varying depths. The existing structure also has sheet piles of different depths at its upstream and downstream ends, with an impervious layer situated at a specific depth below both the structures. The study derives equations for the simulation of the upwards pressure on both the structures, seepage rate, and exit gradient along the downstream bed and the filter at an intermediate location. Our own developed software for the analysis and a commercial software for numerical methods named Finite Element Heat Transfer (FEHT)-version-1are used to calculate these parameters. The accuracy of the analytical and numerical methods is verified by comparing the results with experimental data, which demonstrate a good level of agreement. This study also simulates the impacts of various factors, such as sheet pile configurations, the depth of the stratum beneath the structure, the ratio of effective heads, and the length of the intermediate filter.

Global circulation of low-end expertise: Knowledge, hierarchy, and labor migration in a Burmese oilfield.

This article examines the phenomenon of the "global circulation of low-end expertise" through an exploration of the social dynamics surrounding American oil drillers who migrated from the Pennsylvania oil region to British colonial Burma during the early 1900s to the mid-1930s. These working-class drillers, with practical knowledge in oil drilling acquired through familial and community networks, played a crucial role in operating mechanized oil wells and providing geological expertise in colonial Burma. Positioned between labor-intensive agricultural economies in colonial Asia and the higher echelons of British colonial society, these drillers occupied an intermediate social location. Despite their indispensable expertise, they were marginalized due to their lower social standing, leading to their expertise being disregarded by their superiors and forgotten over time. By understanding the complexities of the "global circulation of low-end expertise," this study sheds light on the social construction and erasure of the expertise held by these working-class drillers, revealing overlooked aspects of global histories of science and labor and highlighting the need to reassess dominant historical narratives on knowledge-labor.