bluuebunny/crossref_metadata_2025 huggingface dataset:
Pressure and Rate Analysis of Fractured Low Permeability Gas Reservoirs: Numerical and Analytical Dual-Porosity Models
Authors: Teklu Tadesse Weldu , Akinboyewa John , Alharthy Najeeb , Torcuk Mehmet A. , AlSumaiti Ali M. , Kazemi Hossein , Graves Ramona M.
Published: January 2013

Most oil and gas production comes from heterogeneous, fractured reservoirs. These fractures can be naturally induced or generated / re-activated through completion and stimulation techniques. In fractured reservoirs, the fluid flow is governed by both fracture and matrix rock-fluid characteristics. Hence, modeling of fractured reservoirs need special considerations to account for these rock-fluid interactions in the matrix and fractures. Currently used formulations of dual-porosity models give a good understanding of heterogeneous fractured reservoir systems. However, determining reservoir properties like effective permeability and estimating the pore-volume or reserves of fractured reservoirs (especially for tight formations) are some of the technical challenges related to reservoir characterization. In industry, similar reservoir properties can be estimated using prolonged rate or bottomhole pressure controlled drawdown analysis.

In this study, numerical dual-porosity models have been implemented and studied for a range of parameters. Grid geometry (radial / linear), type of well (vertical / horizontal), formation tightness (matrix permeability), mode of control (constant flowing pressure / constant flowing rate), and connectivity of fractures (connected and disconnected fracture-continuum) are among the cases investigated to capture the transient behavior of fractured tight gas formations using a numerical dual-porosity model. In addition, for the linear, flow rate controlled case, numerical and analytical model results are compared with good matches.

Fracture and matrix permeability, effective permeability, fracture conductivity, fracture and matrix storativity, and radius of investigation are among the reservoir parameters inferred / calculated from simulation results using the numerical model. Inferred results match the input values to an acceptable degree of accuracy. Hence, it can be concluded that numerical dual-porosity model is a very good tool to analyze transient response of tight formations.
An Approach to Practical Pressure Transient Testing of Multiple Fracture Completed Horizontal Wells in Low Permeability Reservoirs
Authors: Volz Richard , Pinto Elvia , Soto Omar , Jones J. R.
Published: January 2013

The common well/completion configuration for most shale wells is a horizontal well with multiple transverse hydraulic fractures. This is also becoming a common choice for some tight gas reservoirs. Pressure transient testing of this well/completion configuration has not been considered practical or useful since the extraction of completion parameters (fracture conductivity and half-length) out of a recorded response requires an estimate of effective formation permeability. Obtaining an estimate of permeability directly from a buildup or drawdown test can only be done if data from the radial flow period which reflects this parameter is recorded. Unfortunately, for this well/completion configuration in a low permeability reservoir, this flow period occurs only after extremely long shut-in or flowing times.

In the first part of this paper, the possibility of exploiting some combination of the early time flow regimes present in pressure buildup data to overcome these difficulties is investigated. The paper outlines a specialized data collection and analysis approach that can allow data from relatively short (1 to 2 week) pressure buildups to be used to estimate completion parameters and effective flowing phase permeability. The approach relies on an analysis method which combines parameter estimates obtained from well-known early time flow regime equations with special typecurves that correlate derivative responses prior to fracture interference. The method is most reliable when the fracture radial flow period data is captured since this data is needed to place the measured response on the typecurves more uniquely. Possible methods which allow the collection or re-capture of this desirable early time data, despite large wellbore storage effects, are discussed.

The second part of this paper covers an application of the presented analysis method to pressure buildup data from a BP-operated well completed in the Woodford shale of the Arkoma Basin. This pressure buildup test was done as a field trial to prove the viability of the analysis approach presented here. This section includes a description of the test design/ execution and detailed analysis of the pressure buildup data. A reasonable interpretation of this Woodford shale data is consistent with relatively few, but long planar fractures draining nano-Darcy matrix. This interpretation of the stimulated rock volume is unexpected with implications on stimulation and well spacing strategies.
Multiscale Grid Design and Upscaling for a Full Field Tight Gas Reservoir Model on a Next Generation Simulator
Authors: King M. J. , Abacioglu Y.. , Ballin P. R. , Sebastian H. M. , Du S.. , Zhou Y..
Published: January 2013

Reservoir management and simulation of tight gas reservoirs pose several interesting technical challenges. Accurate simulation estimates of the effectiveness of multi-stage fracturing, well rates, the interaction between multiple fractures, and between the reservoir and fractures requires high resolution gridding near the well. These predictions have been achieved in the past through the design of LGR (Local Grid Refinement) grids, or through the use of fractured well indices or cell permeabilities. The latter techniques are based upon steady state concepts and are less able to resolve well rate transients compared to the use of LGR grids.

Decisions on well counts, spacing, and timing also depend upon the interaction between wells. These simulations face specific challenges due to the geology of these reservoirs: in addition to the permeability being low, the connectivity of these reservoirs is intermittent due to the three dimensional spatial patterns of sand deposition and subsequent diagenesis. If these reservoir models are over-averaged or not carefully upscaled, the barriers between sands and internal heterogeneity will be lost, leading to far too optimistic estimates of lateral continuity and under-estimates of infill requirements. The need for accurate flow simulation of these systems has led to the development of spatially adaptive upscaling techniques that honor the vertical discontinuities of the sands in the design of the coarsened simulation grid and which also preserves the heterogeneity within sands.

In the current study, these two approaches have been combined, providing a model with both high resolution and computational efficiency. Starting with a high resolution 3D geologic model, the simulation grid is designed using refinement at the fractured wells, and successively coarsened away from the well, leading to an unstructured numerical problem. Away from the wells, the vertical coarsening utilizes the "pillar-based" adaptive coarsening of Zhou and King, 2011. Simulation is performed using a next generation unstructured commercial simulator. We will report upon the performance of the different techniques in terms of accuracy, computational efficiency, and how they are impacted by different implementations of the multiscale simulation grid design.
Post-Stimulation Fluid Recovery, Every Drop Counts: Case Histories from Saudi Arabia
Authors: Leal J. A. , Duarte J.. , Al-Ghurairi F.. , Izquierdo G. A. , Soriano J..
Published: January 2013

Saudi Aramco, while developing the carbonate Khuff formation sought to continue increasing gas reserves for the Kingdom of Saudi Arabia. A recent optimization initiative was developed to tailor acid-fracturing fluid blends, including a nonionic microemulsion surfactant (ME), to reduce surface tension and modify the contact angle. This initiative resulted in reduced water saturation, higher load recovery, and improved relative permeability to gas, producing the wells back in record time. In recent years, the use of ME in hydraulic fracturing operations has been documented (especially in tight-gas formations) as a key variable to further improve production and increase reserves. These studies, based on both lab research and field data, have shown that ME enhances core permeability to gas and fluid recovery. Particularly for this operator, the use of ME reduced well cleanup time on average by 50%, while also reducing the environmental impact, indirect costs, and increasing cost savings in general.

This paper presents the learning curve with respect to the use of ME, including laboratory fluid screening, surfactant selection, and optimization of acid blends, including corrosion, volume optimization, and lessons learned about field implementation. Additionally, case histories are presented. Evaluation of well flowback and productivity analysis is also included for different permeability scenarios, demonstrating how the use of ME helps speed the cleanup of injected fluids. This evaluation has been useful for selecting the optimum surfactant concentration as a function of reservoir permeability and pressure. Benefits with respect to time optimization and safety are also included based on analysis of actual job data. Because of the benefits obtained, the use of ME is being extended to other field operations, such as well killing, coiled tubing (CT) well interventions, and fluid blends improvement (e.g., inhibited water), which is extensively used in in Saudi Arabia matrix acidizing jobs and proppant fracturing.
A Rigorous Method to Calculate the Rising Speed of Gas Kick
Authors: Ling Kegang , He Jun , Shen Zheng
Published: January 2013

The rising speed of gas kick is an important parameter in well control operation. The position of the gas kick dictates the pressure at the casing shoe, which is usually the weakest point in the openhole section, and the wellhead pressure, which is one of the key factors affecting the blowout preventer and choke folder. In this research we derived a rigorous model to estimate the rising speed of gas kick. Starting from the force analysis and mass conservation we developed the equation to calculate the forces exerting on the gas kick. With the mass of the gas kick the rising speed of the gas kick is calculated. The effect of wellbore temperature profile on the rising of the gas kick is taken into account in the derivation.

Before the development of this model, the estimation of gas kick position is commonly based on experience. In most cases the experience alone is not good enough in well control. The proposed model provides a new approach with solid theoretical base to characterize the rising of gas kick in the hole. With that the whole process of the well control becomes simple and drilling engineers can control the well comfortably. The method can be combined with engineers experience to predict the downhole situation, shut-in casing pressure, and mud rate as functions of position of gas kick. Any deviation from the forecast indicates accidents or downhole problems. Therefore the proposed model is a valuable tool to diagnose the problems in well control.
Formation Breakdown Prediction for the Implementation of Hydraulic Fracturing on a HPHT Tight Gas Reservoir in Oman
Authors: Chavez Juan , Mjeni Rifaat , Briner Andreas
Published: January 2013

The increased global demand for new hydrocarbon resources leads to the exploration in more challenging environments such as shale gas, tight gas and coalbed methane, where hydraulic fracturing is the key technology to unlock the development of these unconventional resources.

In Oman, the challenges imposed by HPHT tight gas formations takes the implementation of hydraulic fracturing to the limits imposed not only by the available fracture technology but by the integrity of the completion components. These challenges increase when stress regime variations are strongly influenced by tectonics. Understanding and predicting the breakdown pressure profile (BDP), and its variability across the target zone, is fundamental for the successful implementation of hydraulic fracturing on tight gas formations.

This paper presents the comprehensive work performed for the integration of log derived data with laboratory rock characterization and field observations, leading to the definition of a BDP prediction methodology for tectonically stressed tight gas formations. Key aspects used as integral part of the methodology of the data acquisition and integration are discussed in detail, including the correlations defined between the BDP, formation injectivity variations and tectonics.

It also discusses how understanding the variations of BDP across selected intervals provides essential information to assess the identification of fracture initiation zones, perforations and hydraulic fracture strategies as well as completion design requirements, leading this to support the successful implementation of hydraulic fractures and further field development.
Calibration of Static Reservoir Models with Dynamic Data for Efficient Tight-Gas Field Development (Wyoming, US)
Authors: Merletti German D. , Pour Rohollah A. , Spain David R.
Published: January 2013

The Wamsutter field is located in south-central Wyoming within the eastern part of the Greater Green River basin. The field covers 1,620 square miles and includes more than 8,500 wells; it produces approximately 450 million cubic ft of gas a day. The Almond formation, which accounts for approximately 85% of the produced gas, was deposited in shallow marine parasequences characterized by strandplain, deltaic, or barrier island complexes and their non-marine counterparts. The upper interval, which was produced extensively, contains the thickest, most laterally continuous and best rock quality. Most of the remaining field development potential remains in sections characterized by thinner and discontinuous facies. In addition to the larger stratigraphic uncertainty, poorer rock quality makes permeability interpretation in uncored wells quite challenging.

We tackle reservoir uncertainty by taking gross depositional interpretation and superimposing gas effective permeability models that honor dynamic measurements. This paper describes our efforts to produce core-calibrated, log-derived, effective permeability models that match zonal contribution from production logging and initial production indices.

The critical steps in the petrophysical workflow are related to the interpretation of the log-derived absolute permeability and core-derived gas relative permeability. Log-derived absolute permeability was addressed by evaluating alternative stochastic (neural network-based) and deterministic models on wireline logs. Core-derived gas relative permeability was tackled by modeling unsteady, pulse decay-type measurements along with capillary pressure tests by rock type.

Alternative gas effective permeability models are integrated over perforated intervals (KegH) and compared to actual reservoir performance. The model exhibiting the best correlation with dynamic data is superimposed on gross depositional maps.

We discuss the assumptions and limitations of the various measurements that make up petrophysical workflows in tight-gas sands as well as their contribution to the location of infill and step-out opportunities.
Maintaining Horizontal Well Stability During Shale Gas Development
Authors: Shen Z.. , Ling Kegang
Published: January 2013

Along with the development of unconventional resource, an increasing number of researches and field operations have been focusing on horizontal shale gas well. The most crucial element of a horizontal well is to enlarge the drainage area, subsequently enhance the well productivity. The technique of hydraulic fracturing has been accepted as an industry standard in developing shale gas play. Therefore, the casing-cement-shale system in the horizontal well should be able to survive from any potential variation of temperature and pressure during well stimulations. The current horizontal well design for casing burst resistance and collapse resistance have been improved by some researchers. Little research can be found to consider the mechanical behavior of shale during the development of a horizontal shale gas well.

This paper focuses on the instability of shale behind the casing and cement in a horizontal shale gas well. The variation of Von-Mise stress with time resulting from the wellbore flowing fluid in the horizontal well is predicted. The proposed model also quantitatively elaborates the difference of temperature distribution in horizontal shale cased hole and open hole. Well stimulation fluid with lower temperature is found to increase the risk of failure in the horizontal shale well. With the model, the down-hole instability of shale gas play in horizontal wells can be evaluated confidently.
Hydraulic Fracturing Critical Design Parameters in Unconventional Reservoirs
Authors: Saldungaray Pedro , Palisch Terry , Shelley Robert
Published: January 2013

Horizontal well drilling and hydraulic fracturing have become the enabling technologies for unconventional reservoir development. From tight gas, to oil and gas-producing shales and coal bed methane, all these resources rely on hydraulic fracturing for its commercial viability. The primary goal of the completion in these ultra-low permeability formations is to provide a conductive path to contact as much rock as possible, through the use of multistage hydraulic fractures along a horizontal lateral. Reservoir contact is optimized by defining the extent of the lateral length, the number of stages to be placed in the lateral, the fracture placement technique and job size. Fracture conductivity is determined by the proppant type and size, fracturing fluid system as well as the placement technique.

While most parameters are considered in great detail in the completion design, the fracture conductivity receives lesser attention. On one side many feel that in extremely low permeability formations hydraulic fractures act as ‘infinitely conductive features’, even with minimal conductivity. On another side many factors that affect the effective conductivity acting in the hydraulic fracture are poorly understood or overlooked. This can lead to a disappointing outcome with wells producing below the reservoir potential.

This paper presents a technique to assess the realistic fracture conductivity at downhole conditions, describe the relationship between conductivity and productivity and its economic implications in proppant selection. The effects of transverse fractures, low areal proppant concentration and flow dynamics, are also considered among other variables.

Fracture modeling and actual field results will be presented to illustrate the optimization process. The case histories included in the paper show the successful implementation of this method in shale gas and liquids rich formations.
Design and Application of Hydraulic-Walking Incremental Launching Equipment
Authors: Bian Yongming , Jiang Jia , Jing Zhong , Han Bangxin , Li Anhu , Liu Guangjun
Published: January 2013

This work designs a novel hydraulic-walking incremental launching equipment. The working principle of the
equipment is proposed. Considering that the contact in incremental launching construction is a typical elastic contact
problem, and changes in contact state will directly affect the stability of the incremental launching, this work proposes the
equilibrium equations of computational contact mechanics and numerical analysis method for the incremental launching
equipment through analyzing the working process of the equipments. The proposed model and method are applied in the
analysis of typical working conditions of the incremental launching of Donghua Bridge. The structural characteristics in
the construction process are analyzed and discussed. The analysis results show that the strength and stability of the steel
box girder can meet the construction requirements. The incremental launching of Donghua Bridge was completed successfully.
The proposed model and method can be used to predict and analyze the structural performance in incremental
launching construction as well as provide theoretical reference and analysis method for similar constructions.
Reversed-phase HPLC retention data in correlation studies with in lipophilicity molecular descriptors of carotenoids
Authors: Podunavac-Kuzmanovic Sanja , Jevric Lidija , Tepic Aleksandra , Sumic Zdravko
Published: January 2013

Influence of chemical structure on the lipophilicity of isolated free
carotenoids from paprika oleoresin has been studied by QSRR approach
(Quantitative structure-retention relationship). The chromatographic behavior
of these compounds was investigated by using reversed phase high-pressure
liquid chromatography (RP HPLC). Retention mechanism has been determined
using the following mobile phase: acetone -water, on reversed - phase column
(SB-C18). A variety of lipophilicity parameters (logP) were calculated by use
of different software products. On the basis of correlations, the nonlinear
structure-activity models were derived between the retention constants, tr
(retention time of investigation compounds), and logP values. Five high
quality QSRR models were found to have a good predictive ability and close
agreement between experimental and predicted values. The study showed that
the retention constants can be used as a measure of lipophilicity of
investigated compounds at a high significant level.
Identifying the Relationships between Water Quality and Land Cover Changes in the Tseng-Wen Reservoir Watershed of Taiwan
Authors: Chu Hone-Jay , Liu Chun-Yu , Wang Chi-Kuei
Published: January 2013

The effects on water quality of land use and land cover changes, which are associated with human activities and natural factors, are poorly identified. Fine resolution satellite imagery provides opportunities for land cover monitoring and assessment. The multiple satellite images after typhoon events collected from 2001 to 2010 covering land areas and land cover conditions are evaluated by the Normalized Difference Vegetation Index (NDVI). The relationship between land cover and observed water quality, such as suspended solids (SS) and nitrate-nitrogens (NO3-N), are explored in the study area. Results show that the long-term variations in water quality are explained by NDVI data in the reservoir buffer zones. Suspended solid and nitrate concentrations are related to average NDVI values on multiple spatial scales. Annual NO3-N concentrations are positively correlated with an average NDVI with a 1 km reservoir buffer area, and the SS after typhoon events associated with landslides are negatively correlated with the average NDVI in the entire watershed. This study provides an approach for assessing the influences of land cover on variations in water quality.
Malédiction. (Sur le fétichisme)
Authors: Le Bihan Anne
Published: January 2013

Le fétichisme, paradigme de la perversion pour Freud, a eu une valeur euristique particulière pour la psychanalyse. Il n’est pas seulement réponse, mais aussi exercice d’une question ; le sujet pervers n’est pas sans symptôme. Le sujet fétichiste se soutient d’un désir « glorieux », c’est-à-dire instable, précaire, toujours menacé de choir. Le rapport de l’écrivain André Gide à la lettre et aux Lettres, étudié par Lacan, est ici à nouveau interrogé ; il apporte une contribution supplémentaire à l’étude du fétichisme.
L'instance de la lettre pour l'Homme aux loups
Authors: Bordas Éric
Published: January 2013

Le rêve d’une Wespe et un lapsus, Espe, rapporté par l’Homme aux loups dans sa cure avec S. Freud, nous permettent, en nous référant à l’instance de la lettre de Jacques Lacan, de lire ce lapsus, à partir de l’élision de la lettre W, comme le chiffrage de ce que l’Homme aux loups n’a pu reconnaître dans son analyse.
L'articulation du singulier et du « vivre ensemble », encore… Entre orthodoxie et hérésie, « l'humus humain »
Authors: Sauret Marie-Jean
Published: January 2013

Nous proposons de situer l’article de Regnier Pirard dans le cadre de la discussion sur la dimension historique ou non de l’articulation du sujet et du lien social. Névrosés, psychotiques et pervers contemporains témoignent après tout d’une « adaptation » non pas transhistorique mais prenant appui sur les caractéristiques de notre « vivre ensemble ». Et nous considérons comme « humusien » non pas ceux qui soutiennent cette position, mais ceux qui contribuent au débat autour du réel qui divise les uns et les autres.
Quasi-polynomial mixing of the 2D stochastic Ising model with “plus” boundary up to criticality
Authors: Lubetzky Eyal , Martinelli Fabio , Sly Allan , Toninelli Fabio L.
Published: January 2013

We considerably improve upon the recent result of [37] on the mixing time of Glauber dynamics for the 2D Ising model in a box of side

L

at low temperature and with random boundary conditions whose distribution

\mathbf P

stochastically dominates the extremal plus phase. An important special case is when

\mathbf P

is concentrated on the homogeneous all-plus configuration, where the mixing time

T_{\mathrm{MIX}}

is conjectured to be polynomial in

L

. In [37] it was shown that for a large enough inverse-temperature

\beta

and any

\varepsilon >0

there exists

c=c(\beta,\varepsilon)

such that

\lim_{L\to\infty}\mathbf P(T_{\mathrm{MIX}}\ge \exp({c L^\varepsilon}))=0

. In particular, for the all-plus boundary conditions and

\beta

large enough

T_{\mathrm{MIX}}\le \exp({c L^\varepsilon})

. Here we show that the same conclusions hold for all

\beta

larger than the critical value

\beta_c

and with

\exp({c L^\varepsilon})

replaced by

L^{c \log L }

(i.e. quasi-polynomial mixing). The key point is a modification of the inductive scheme of [37] together with refined equilibrium estimates that hold up to criticality, obtained via duality and random-line representation tools for the Ising model. In particular, we establish new precise bounds on the law of Peierls contours which complement the Brownian bridge picture established e.g. in [20,22,23].
Reeb vector fields and open book decompositions
Authors: Colin Vincent , Honda Ko
Published: January 2013

We determine parts of the contact homology of certain contact 3-manifolds in the framework of open book decompositions, due to Giroux. We study two cases: when the monodromy map of the compatible open book is periodic and when it is pseudo-Anosov. For an open book with periodic monodromy, we verify the Weinstein conjecture. In the case of an open book with pseudo-Anosov monodromy, suppose the boundary of a page of the open book is connected and the fractional Dehn twist coefficient

c

equals

k=n

, where

n

is the number of prongs along the boundary. If

k ≥ 2

, then there is a well-defined linearized contact homology group. If

k ≥ 3

, then the linearized contact homology is exponentially growing with respect to the action, and every Reeb vector field of the corresponding contact structure admits an infinite number of simple periodic orbits.
Automorphism groups of minimal real-analytic CR manifolds
Authors: Juhlin Robert , Lamel Bernhard
Published: January 2013

We show that the local automorphism group of a minimal real-analytic CR manifold

M

is a finite dimensional Lie group if (and only if)

M

is holomorphically nondegenerate by constructing a jet parametrization.
US Science in Peril
Authors: Walensky Rochelle P. , Walensky Loren D.
Published: February 2025

This Viewpoint discusses the importance of federal funding of biomedical research from the National Institutes of Health to scientific discovery, advancements in individual and public health, and the support of the US’ community of scientists.
Sale of Private Equity–Owned Physician Practices and Physician Turnover
Authors: Berquist Victoria , Klarnet Lev , Dafny Leemore
Published: February 2025

Importance

Private equity (PE) acquisition of physician practices is increasing, with owners targeting sales, or exits, in 3 to 7 years. Little is known about the association of exit with physician retention and subsequent employment.

Objective

To examine whether PE exit of physician practices is associated with changes in physician retention and subsequent choice of practice size.

Design, Setting, and Participants

Using data from the Centers for Medicare & Medicaid Services Doctors and Clinicians National Downloadable File from December 31, 2014, to December 31, 2020, this case-control study compared employment changes for physicians at PE-exiting practices sold between January 1, 2016, and December 31, 2018 (treatment group), with employment changes for matched control physicians in practices not sold by PE owners but with the same specialty, hospital referral region, practice size, and time period. Physicians billing fee-for-service Medicare during the study period were eligible for inclusion. A difference-in-differences design was used to compare retention between the treatment and control groups in the 2 years before and after exit using a multinomial logit model that adjusted for physician decade of graduation. Data were analyzed from August 1, 2023, to November 9, 2024.

Exposure

Exit of a PE-owned physician practice.

Main Outcomes and Measures

Physician employment outcomes included staying (continuing to bill through the initial practice), working elsewhere (only billing through other practices), and retirement (no longer billing). Whether a physician left to a join large (>120-physician) practice was also evaluated.

Results

Of the 1215 physicians included in the analysis (405 at 70 PE-exiting practices and 810 matched controls; 814 [67.0%] male and 401 (33.0%) were female. Physicians in all PE-exiting practices were typically in practices of more than 20 physicians (471 [65.2%]) and often in the South (373 [51.7%]). Dermatology was the leading specialty (216 [29.9%]), followed by family medicine (94 [13.0%]). Physicians employed in PE-exiting practices were 16.5 (95% CI, 10.6-22.3) percentage points less likely to continue working in that practice 2 years after exit compared with matched controls. There was no significant change in the probability of retirement (0 percentage points; 95% CI, −4.1 to 4.0). Physicians in PE-exiting practices were 10.1 (95% CI, 6.5 to 13.7) percentage points likelier than matched controls to join a large practice of more than 120 physicians.

Conclusions and Relevance

In this case-control study, PE exit was followed by an increase in physician turnover and subsequent employment at a large (>120-physician) practice relative to matched controls, notwithstanding similar turnover rates between these physicians and matched controls prior to exit. The increase in physician turnover and consolidation following PE exits has important implications for patients, physicians, investors, and physician markets.
Patients’ Trust in Health Systems to Use Artificial Intelligence
Authors: Nong Paige , Platt Jodyn
Published: February 2025

This survey study evaluates whether US adults trust health systems to use artificial intelligence responsibly and examines characteristics associated with attitudes related to the use of artificial intelligence in health care.
West Virginia researchers look at quit attempts before success
Authors: Knopf Alison
Published: February 2025

Relapse when giving up opioids, alcohol, cigarettes, or other drugs is common. Now researchers at the Fralin Biomedical Research Institute at VTC's Addiction Recovery Research Center have looked at the number of tries that may be needed before treatment is successful.
Broadening the Healthy Aging Paradigm: Inclusion of Gestation, Development, and Reproductive Health
Authors: Yao Lan , Eikelboom John , Macnab Andrew , Yu Zhuo , Cao Yanhong , Wei Wei , Sun Shuqiu , Khalil Asma , Cho William C. , Qamar Farah Naz , Kremsner Peter , Oliu‐Barton Miquel , Wang Lishi , Sisa Ivan , Marks Florian , Wang Cong‐Yi , Graff J. Carolyn , Howard Scott C. , Gu Tianshu , Maida Marcello , Prochownik Edward V , Mashe Tapfumanei , Fly Alyce D , Hui Yang , Maier Andrea B. , Aleya Sami , Sun Dianjun , Wang Gang , Bischof Evelyne Yehudit , Aleya Lotfi , Gu Weikuan
Published: February 2025

The prevailing focus of lifespan health research has predominantly centered on “healthy aging”. This oversight may hinder the understanding of health across the lifespan, as disorders in earlier stages can substantially impact overall health and longevity. Aging, conceptually, begins at gestation. The trajectory of an individual's health is influenced from the earliest stages of life, where adverse conditions can set a foundation for lifelong health challenges. For example, suboptimal conditions during gestation leading to premature birth can predispose individuals to various health issues later in life. Additionally, precocious puberty defined as the onset of sexual maturity before eight years of age or early menopause—occurring before 50 years of age requires medical intervention and is indicative of atypical aging processes. To address these critical gaps in lifespan health research, the expansion of medical lexicons and research categorizations is advocated to include “healthy gestation,” “healthy development,” and “healthy reproduction” alongside “healthy aging.” This broader terminology will enable a more comprehensive investigation of disorders at all life stages. An integrative approach underscores the interconnectedness of all life stages and the continuous nature of aging, advocating for a seamless continuum in health research and interventions from gestation through late adulthood.
Mechanical Properties and Failure Mechanisms of Carbon Fiber/Resin Composites with Hot Press, Single‐Vacuum‐Bag, and Double‐Vacuum‐Bag Processes
Authors: Ren Liangliang , Zhang Deyuan
Published: February 2025

In order to compare the mechanical properties of materials, acquire the crack propagation law and failure mode under different processes of carbon fiber/resin composites, the hot press process, double‐vacuum‐bag (DVB) process, and single‐vacuum‐bag (SVB) process were used to manufacture laminates in this paper, the void content and void morphology of the composite materials were observed by ultrasonic C‐scan, optical microscope, and scanning electron microscope. Four different types of mechanical tests were carried out: tensile, compressive, bending, and short‐beam shear tests, and the fracture morphology of the specimens was observed and analyzed. The failure mechanisms of the materials under different processes were explored based on the stress analysis. It is found that in the materials manufactured by SVB process, voids can induce stress concentration effect, reduce the stress area and interlayer bonding force, and cracks are more prone to initiate and propagate around voids. These are all factors contributing to the reduction of bearing capacity and accelerating the failure process in the material. The void contents of laminates manufactured by DVB process and hot press process are extremely low, it is difficult for cracks to propagate within the material, and the composites can maintain excellent mechanical properties.
Optimization and Comparative Analysis of Machining Performance of Al–Cu–SiC–GNP Composite: Influence of Reinforcement Variations Using Machine Learning, RSM, and ANOVA Validation
Authors: Rajkumar Reddy Madduri , Gugulothu Santhosh Kumar , Krishnaiah Talari , Grandhi Suresh Kumar
Published: February 2025

This study aims to optimize and analyze the machinability of Al–Cu–SiC–GNP composites using advanced techniques such as machine learning, (RSM), and (ANOVA). The composites are fabricated using an ex situ stir casting process with varying reinforcement percentages of silicon carbide (SiC) and graphene nanoplatelets (GNP) (2, 3, and 5%), and their machinability is evaluated during water jet machining. The key machinability parameters analyzed are material removal rate, surface roughness (Ra), and kerf width. Experimental findings reveal that reinforcement percentages significantly influence machinability. Optimal results are achieved with 5% SiC, 3% GNP, 300 MPa, and 120 mm min−1, balancing enhanced mechanical properties and efficient machining. ML models, including decision tree, random forest, support vector machine, and artificial neural network (ANN), are applied to predict machining outcomes. Among these, the ANN model exhibits the highest predictive accuracy, capturing complex nonlinear interactions between input parameters. The study also validates results through RSM and ANOVA, confirming the statistical significance of reinforcement and machining parameters on machinability. This research provides a robust framework for optimizing hybrid composite machining and offers valuable insights into the relationship between reinforcement content, machining parameters, and performance outcomes, making it highly applicable to aerospace and automotive.
Heteroatom‐Doping Modulates Metal‐Support Interactions in Carbon‐Supported Cobalt Catalysts to Accelerate Polysulfide Redox for Lithium–Sulfur Batteries
Authors: Sun Yinjing , Wang Yingli , Li Caixia , Zhang Qi , Wang Lei , Lv Qingliang , Feng Shouhua
Published: February 2025

High redox kinetic barriers and the severe shuttle effect of lithium polysulfides (LiPSs) are two primary challenges for the practical deployment of lithium‐sulfur (Li–S) batteries. Herein, highly dispersed Co nanoparticles embedded into S, N co‐doped hollow chained carbon sphere (Co@SNC) are well‐designed and prepared and served as an effective host catalyst for Li–S batteries. Doped S‐atoms can effectively modulate the electronic metal‐support interaction between Co nanoparticles and carbon matrix, which induces charge redistribution and increased d‐orbital energy levels. Co@SNC can provide strong chemical interaction with LiPSs and reduce the Li+ diffusion barrier, which can effectively anchor LiPSs and accelerate the LiPSs conversion kinetics. The hollow chain‐like structure of Co@SNC also synergistically suppresses LiPSs shuttling and enables high sulfur loadings and rapid charge/mass transfer. These merit the Li–S batteries based on Co@SNC with high reversible capacity, impressive rate performance, and prolong cycling stability with a low capacity decay of 0.024% per cycle over 1700 cycles. Notably, the Co@SNC/S electrode still delivers a high initial capacity of 814.9 mAh g−1 and superior cycling performance even at high sulfur loading and poor electrolytes.
Entropy Driving “Quasi‐Zero Strain” Stepwise Multicationic Redox Chemistry Toward a High‐Performance NASICON‐Cathode for Na‐Ion Batteries
Authors: Jin Can , Wang Yao , Zhao Xudong , Jin Junteng , Li Zhenyou , Qu Xuanhui , Jiao Lifang , Liu Yongchang
Published: February 2025

Achieving multicationic redox reactions with low lattice strain accumulation upon repeated sodiation/desodiation processes is pivotal for developing high‐energy and long‐durability Na superionic conductor (NASICON)‐type cathodes but still a formidable task. Herein, a novel NASICON‐structured high‐entropy Na3.4VMn0.2Fe0.2Al0.3Cr0.3(PO4)3 (HE‐NVMFACP) cathode is delicately devised, where the entropy‐driving stepwise Fe2+/Fe3+, V3+/V4+/V5+, Mn2+/Mn3+/Mn4+, and Cr3+/Cr4+ redox couples not only trigger the multielectron transfer chemistry, but also alleviate the lattice strain accumulation. Consequently, the HE‐NVMFACP cathode exhibits a high reversible capacity of 151.3 mAh g−1 with an admirable energy density of 520.5 Wh kg−1, and an impressive “quasi‐zero strain” behavior (1.33% cell volume change) during the whole charge‐discharge process. Meanwhile, an excellent rate capability of 90.4 mAh g−1 at 50 C and an ultralong cycling life of 91.9% capacity retention after 5000 cycles are demonstrated. Advanced in situ/ex situ techniques reveal the complete solid‐solution behavior and highly reversible stepwise multicationic redox mechanism of HE‐NVMFACP upon Na+ uptake/release, and the rapid electrode process kinetics of HE‐NVMFACP are confirmed by systematic electrochemical measurements and theoretical computations. Furthermore, the HE‐NVMFACP||hard carbon Na‐ion full batteries are assembled in both coin and pouch configurations, manifesting bright application prospects. The present high‐entropy strategy provides invaluable perspectives for designing high‐energy and long‐life NASICON‐cathodes for sodium‐ion batteries.
Recent Advances in the Preparation of Gallium‐based 2D Materials and Devices Based on Gallium Liquid Metal
Authors: Gao Fangliang , Li Zexi , Li Shuti
Published: February 2025

Gallium (Ga) liquid metal has become highly suitable for the preparation of 2D materials due to its unique physical and chemical properties, such as high surface tension, low‐melting‐point, and ease of oxidization. Ga has a very low melting point and becomes a silver‐white liquid at 29.76 °C. In the air, the surface of Ga can spontaneously undergo a Cabrera‐Mott oxidation reaction to form an ultra‐thin oxide layer. This self‐formed oxide layer is considered a natural 2D material, and other 2D materials can be derived by post‐processing the oxide layer. In recent years, advancements in surface oxidation techniques for Ga have led to the successful preparation of various Ga‐based 2D materials. These materials possess unique electronic and optical properties along with a simple, low‐cost preparation process, offering broad potential for advancing new electronic devices. This review examines recent research on the preparation of Ga‐based 2D materials derived from Ga and its alloys. It discusses the potential applications of different kinds of Ga‐based 2D devices across multiple fields. Therefore, it can be expected that Ga will play a more significant role in the development of material science in the future.
Control Over Kinetic Self‐Assembly of Phthalocyanine into Photothermal Nano‐Vaccine Enabling Tunable Superlarge Absorption Redshift
Authors: Zhang Shuo , Li Yongxin , Zheng Jilu , Liu Chunlei , Diao Chunyang , Zhao Luyang , Liu Chunzhao
Published: February 2025

Supramolecular near‐infrared (NIR) nanomaterials show great application prospects in cancer photothermal immunotherapy. However, the direct self‐assembly of photothermal nanomaterials absorbed in biological transparent window and control over their absorption properties through aggregation behavior remains a grand challenge. Here, the control over superlarge absorption redshift (ranging from 105 nm to 150 nm) of mono‐α‐substituted carboxy zinc phthalocyanine (αZnPc) through kinetic assembly methodologies is demonstrated, resulting in the fabrication of photothermal nanoagents within tissue‐transparent NIR window. Tailoring the solvent polarity allows for the manipulation of kinetic pathways, leading to a variety of self‐assembled structures exhibiting distinct αZnPc macrocycle stacking modes that attribute to their different absorption redshift properties. Mechanistic studies of the relationship between solvent polarity and pathway complexity revealed the energy landscape that governs the unique kinetic behavior. The specific stacking mode and conformation conforming to the charge‐transfer model within these αZnPc assembled structures have been revealed by theoretical calculations. Crucially, the αZnPc nanostructures show remarkable physiological stability and robust photothermal performances within biological transparent window, efficiently ablating primary tumors and triggering immunogenic cell death. This effect is further augmented by the immunomodulatory effects of thymopentin, exhibiting vaccine‐like capabilities in suppressing the growth of distant tumors. This research demonstrates unprecedented levels of control over supramolecular structures and their superlarge red‐shifted absorption, providing great opportunities for future design and construction of supramolecular NIR materials with fascinating properties toward cancer treatments.
Longer Acting Injectable: Continuous, Linear Release of a Progestin Contraceptive From an Oxidized Porous Silicon Host
Authors: Hollett Geoffrey , Fan Ruhan , Kumeria Tushar , Leonard Heidi , Kim Byungji , Martin Taylor R. , Ipekci Irmak , Wang Joanna , Byun Jiuk , Chan Nicole A. , Pierron Amber , Moore Curtis E. , Ayres Jennifer , Sailor Michael J.
Published: February 2025

Maintaining stable drug concentrations in the bloodstream is a challenge for injectable hydrophobic progestin contraceptives. This work investigates porous silicon dioxide (pSiO2) microparticles as a delivery vehicle for progestins via melt‐infiltration of drugs into the mesopores. The pSiO2 is prepared through electrochemical anodization of single‐crystalline silicon followed by thermal oxidation, yielding vertically oriented pores (≈50 nm diameter) with porosity varied (between 35–75%) to optimize drug loading and release. Among the progestins tested, etonogestrel and levonorgestrel (LNG) decompose near their melting points, preventing melt infiltration. However, addition of 20% cholesterol by mass suppresses the melting point of LNG sufficiently to enable loading without degradation. Mass loadings exceeding 50% (drug: drug + carrier) are achieved for segesterone acetate (SEG) and LNG, retaining drug crystallinity as confirmed by X‐ray diffraction. In vitro, both SEG and LNG‐loaded pSiO2 display sustained drug release for up to 3 months, with reduced burst release, more constant steady‐state concentrations, and a substantially reduced tail compared to pure LNG or SEG, or SEG loaded into pSiO2 from a chloroform solution. In a pilot in vivo study, SEG‐loaded pSiO2 microparticles are well tolerated in 20‐week‐old female rats over a 25‐week period, with no signs of toxicity.
Two‐Dimensional Cr3Te4/WS2/Fe3GeTe2/WTe2 Magnetic Memory with Field‐Free Switching and Low Power Consumption
Authors: He Kun , Li Bailing , Nie Jianhang , Hou Yanglong , Huan Changmeng , Hong Min , Du Jiantao , Chen Yang , Tang Jingmei , Yi Chen , Feng Ya , Liu Shaojun , Wu Sumei , Liu Miaomiao , Zhang Hongmei , Guo Yukun , Wu Ruixia , Li Jia , Liu Xingqiang , Liu Yuan , Wei Zhongming , Liao Lei , Li Bo , Duan Xidong
Published: February 2025

Spin‐orbit torque (SOT) magnetic memory technology has garnered significant attention due to its ability to enable field‐free switching of magnets with strong perpendicular magnetic anisotropy (PMA). However, concerns regarding power consumption of SOT‐memory are persisting. Here, this work proposes a method to construct magnetic tunnel junction (MTJ) by transferring chemically vapor‐deposited two‐dimensional (2D) Cr3Te4/WS2 van der Waals (vdW) heterostructures onto 2D Fe3GeTe2 (FGT) magnet. The robustness and tunability of 2D magnets allow MTJs to exhibit non‐volatility, multiple output states, and impressive cycling durability. MTJs with thin WS2 barriers (fewer than six layers) exhibit a linear tunneling effect, achieving a low resistance‐area product (RA) of 15.5 kΩ·µm2 using bilayer WS2, which facilitats low‐power operation. Furthermore, the different 2D magnets display a significant anti‐parallel window of up to 8 kOe. SOT‐memory based on the typical MTJ demonstrates a low write consumption of 0.3 mJ and read consumption of 9.7 nJ, marking a significant advancement in 2D vdW SOT‐memory. This research has pointed out a new direction for constructing low power consumption SOT‐memory with PMA field‐free switching.