bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Structure on the Corrosion of Glassy Copper-Zirconium Alloys
Authors: Turn J. C. , Latanision R. M.
Published: June 2011

Differences in structure between crystalline and glassy copper-zirconium alloys lead to subtle increases in the corrosion rate of crystalline compared to glassy material. Glassy alloys of Cu60Zr40 were melt spun and subsequently devitrified, yielding single phase polycrystalline material. Comparing the potentiodynamic polarization response of these structural types revealed no significant difference in ϕcorr. ba, bc, icorr. and io. Other alloys, Cu58Zr42 and Cu55Zr45, compared in glassy and crystal-line forms revealed that inhomogeneity, caused by precipitation of a second phase, did not alter the corrosion behavior from that of single phase Cu60Zr40. Corroded glassy surfaces were generally smooth except for scattered hemispherical features, while crystalline surfaces were densely populated with these features. Corrosion of copper-zirconium alloy occurs by the selective dissolution of zirconium in the vicinity of ϕcorr, whereas, at potentials noble to −0.1 VSCE, copper contributes to the anodic current. Above approximately 0.0 VSCE the alloys passivate. Results of potentiodynamic polarization studies suggest that for these alloys, unlike transition metal-metalloid glasses, devitrification does not significantly affect the corrosion kinetics of copper-zirconium alloys.
Corrosion of Medium Carbon Steel in Aqueous Solutions Containing Fluoride Ions at 300 C
Authors: Mayer P. , Manolescu A. V. , Rasile E. M.
Published: June 2011

The accelerated internal corrosion in boiler evaporators results from an unfavorable coincidence of adverse thermohydraulic conditions, boiler water contamination, and fabrication defects. Boiler tube material (medium carbon steel, Type SA210) was exposed in static autoclaves to aqueous solutions of HF, FeF3, and NiF2 at 300 C, and the rate of attack and morphology of the resulting scales were established. For comparison, parallel tests were conducted in aqueous solutions containing chloride ions. This work establishes the role played by fluoride contamination of the boiler water.
Pitting Corrosion of Inconel 600 in High Temperature Chloride Solution under Controlled Hydrodynamic Conditions
Authors: Karaminezhaad-Ranjbar M. , Mankowski J. , Macdonald D. D.
Published: June 2011

Pitting corrosion of mill annealed Inconel 600 in buffered 0.1M NaCl solution was studied as a function of temperature (25 to 250 C) under well-defined hydrodynamic conditions (flow velocities from 0 to 158 cm/s) in an annular flow channel. Flow velocity had no significant effect on the breakdown potential over the entire temperature range studied, but some influence on the morphology of attack was noted. Temperature was found to be an important parameter, however, in determining the susceptibility of mill annealed Inconel 600 to localized attack in buffered 0.1M NaCl solution.
The Effect of Nitrogen on the Sensitization of AISI 304 Stainless Steel
Authors: Mozhi T. A. , Clark W. A. T. , Nishimoto K. , Johnson W. B. , Macdonald D. D.
Published: June 2011

Thermodynamic calculations have been used to construct time temperature sensitization (TTS) diagrams for AISI 304 stainless steels (SS). The quantitative Stawstrom and Hillert model, which is based on chromium diffusion control of sensitization, was used to calculate the TTS diagrams. Electrochemical potentiokinetic reactivation (EPR) tests were performed on these steels, with various nitrogen additions, to obtain the experimental TTS curves. The calculated and experimental TTS diagrams have been compared to better understand nitrogen addition effects on the sensitization kinetics of AISI 304 SS. These results indicate that nitrogen additions below 0.16 wt% retard the sensitization kinetics; one possible mechanism by which this is achieved is an increase in chromium concentration adjacent to the grain boundaries, which decreases the chromium concentration gradient between the austenite matrix and the grain boundaries and hence retards carbide growth.
On the Mechanism of Cathodic Protection
Authors: Dexter S. C. , Moettus L. N. , Lucas K. E.
Published: June 2011

Changes in the distribution of anodic sites on steel and aluminum surfaces have been monitored by applying a pH-indicating dye and observing how the color pattern on the surface changes as cathodic protection is applied. In addition, cathodic polarization curves for steel in seawater have been correlated with 120-day weight loss measurements and surface morphological observations for specimens receiving various levels of cathodic protection. The results are discussed in terms of the Mears and Brown, Hoar, and LaQue theories of cathodic protection and their implications as to the criteria for cathodic protection and the consequences of underprotection.
Stress Corrosion Cracking Behavior of 300M Steel under Different Heat Treated Conditions
Authors: Padmanabhan R. , Wood W. E.
Published: June 2011

The resistance of 300M steel to stress corrosion cracking in a 3.5% NaCl solution was studied as a function of heat treatment. Threshold stress intensity was affected by microstructural features, including prior austenite grain size, amounts of retained austenite, and twins, in addition to grain boundary segregation and fracture toughness of the steel. Crack growth rate was also dependent on microstructure and segregation, but the number of constraint points exerted the maximum influence. The effect of a modified heat treatment, which has been shown to improve all investigated mechanical properties to a significant extent, upon stress corrosion cracking (SCC) properties, was also studied. This heat treatment resulted in significantly higher threshold stress intensity and lower crack growth rate. The results are discussed in terms of microstructure and fractography.
The Effect of Ammonium Chloride and Fluid Velocity on the Corrosion Behavior of Copper in Sodium Bicarbonate Solutions
Authors: Akkaya M. , Ambrose J. R.
Published: June 2011

The effect of ammonium chloride additions on the corrosion behavior of copper in 1 N sodium bicarbonate solutions has been characterized using a rotating ring-ring linear cyclic voltammetry technique. The experimentation and solution compositions used were selected to account for an unusually high incidence of pitting found to occur on interior surfaces of copper cold-water plumbing fixtures in the vicinity of neutral soldering flux residues. Although concentrations of ammonium chloride above 0.05 N were found to result in an increase of corrosion rate often attributed to the stabilization of a cuprous ion complex metal dissolution reaction product, under freely corroding conditions in an air-saturated solution, corrosion of copper metal would occur by an anodic process in which current was distributed between both soluble metal ions (cuprous and cupric ions) and insoluble corrosion product deposits. Although increases in applied potential or relative fluid velocity produced increases in the total corrosion rate, there was also a change in current distribution between the various components of the overall anodic process.

Results from this study suggest that soluble and insoluble corrosion products (cathodically or anodically generated during a single linear polarization cycle) affect corrosion behavior during either successive cycles or extended exposure periods to such an extent that sole reliance on single-cycle anodic polarization behavior for the prediction of long-term corrosion resistance for copper and its alloys should be avoided.
Surface Composition of Stainless Steel during Propagation of Crevice Corrosion
Authors: Zakipour S. , Leygraf C.
Published: June 2011

The surface composition of AISI 304 and 316 stainless steels has been investigated by means of focusing, scanning Auger electron spectroscopy (AES) on locally corroded areas formed upon exposure in chloride media with different acidity and under potentiostatic control. Within 1 minute of dissolution in the active state, there is formed a surface layer, which is markedly enriched in Cr. The existence of this layer is a consequence of the selective dissolution of Fe during initial active dissolution and of alloy components entering the solution in proportions equal to those in the bulk alloy during later stages of active dissolution. In addition, direct evidence is given of the precipitation onto the Cr rich surface region of a few monolayers of Cu2S at higher pH (4 to 8) in the solution and of metallic Cu nodules at lower pH (1 to 2). The localization of these layers within the local attack as well as the localization of a thin Mo containing sulfide layer can be directly related to the chemical dissolution of sulfide inclusions during initiation of crevice corrosion.
Influence of a CuS04 Treatment on Atmospheric Steel Rust Formation a Mössbauer Spectroscopy Study
Authors: Saragovi-Badler C. , Maier I. A. , Labenski F.
Published: June 2011

Mössbauer spectroscopy has been used to analyze the rust layers formed on a weathering steel and a 1010 steel exposed for 10-1/2 months to an urban-industrial atmosphere. No significant difference was found comparing the rusts of both steels: they were composed by γ-FeOOH, superparamagnetic α-FeOOH, and an amorphous or gel-like compound. γ-FeOOH is more abundant in the internal rust layers, whereas the amount of α-FeOOH and the amorphous compound increase in the external rusts. Part of the samples received an initial copper deposit by immersion of the steel plates in a CuSO4 bath. Mössbauer spectroscopy analysis showed that the amorphous substance was no longer present in the rusts of those specimens; that is, the rusts of both steels were formed only by γ-FeOOH and α-FeOOH.
Crack Initiation and Growth Analysis by Direct Optical Observation during SSRT in High Temperature Water
Authors: Kawakubo Takashi , Hishida Mamoru
Published: June 2011

The stress corrosion cracking behavior during the slow strain rate test (SSRT) has been investigated in high temperature water. SSRTs were performed on center-notched thin plate specimens of sensitized Type 304 stainless steel. A direct optical observation system consisting of single crystal sapphire windows was employed to separate the SCC into an initiation and a growth stage, and to measure the crack growth rate. Effects of the extension rate, test temperature, and dissolved oxygen concentration on the crack initiation and growth were examined. The crack growth data were analyzed with different variables, including the elastic plastic fracture mechanics parameters. The best interpretation of the crack growth rates is obtained by plotting them vs the time differential of J-integral, which is an estimate of the crack tip deformation rate during SSRT.
Effect of Platinum Elements Additions on the Active Dissolution of Plastic Chromium in Sulfuric Acid
Authors: Tomashov N. D. , Chernova G. P. , Ustinsky E. N.
Published: June 2011

Alloys based on plastic chromium with 0.1 to 0.4 mass % Ru, Pd, Ir, or Pt were investigated in 40% sulfuric acid in active state under cathodic polarization (−0.175 V). All of the studied additions of alloying elements are responsible for the reduced anodic dissolution of chromium. The corrosion resistance of alloys depends on the concentration and nature of the alloying additions. Two mechanisms decelerating the active dissolution of the cathode-modified chromium have been established, i.e., blocking mechanism (cathodic component atoms block the active points in the lattice) and screening mechanism (cathodic component, while getting crystallized on the surface, partly screens the latter).
Electrochemical Study of Stainless Steels in High Temperature Urea Solutions
Authors: Matsumoto K. , Shinohara T.
Published: June 2011

The corrosion of stainless steels in high temperature and high pressure urea solutions was studied by electrochemical measurements together with immersion tests to elucidate the corrosion mechanism and to rationalize the corrosion prevention methods. It was demonstrated that the corrosion of stainless steel was either active region dissolution, caused by the lack of dissolved oxygen, or dissolution near the transpassive region in process fluids with sufficient oxygen. High Cr/low Ni (or Ni-free)/Mo stainless steels were readily passivated. Stainless steels with high Cr content and/or with homogeneous distribution of Cr had superior resistance to corrosion near the transpassive region. As the temperature rose, the passivation current increased. At the same time, dissolution of oxygen into the simulated process fluids was more pronounced; therefore, high temperature was not necessarily unfavorable for passivation. Ammonia content in the process fluids strongly affected the passivation current; the current increased as the NH3:H2O molar ratio fell. By comparing the environmental variables in urea plants with the obtained data, guidelines for suitable corrosion prevention methods were developed.
ARCTAS-A ground-based observational campaign and meteorological context, interior Alaska, April 2008
Authors: Atkinson D. E. , Sassen K. , Hayashi M. , Cahill C. F. , Shaw G. , Harrigan D. , Fuelberg H.
Published: June 2011

Abstract. Arctic aerosol loading in interior Alaska displays a strong seasonality, with pristine conditions generally prevailing during winter months and increasing frequency of midlatitude air intrusions occurring in spring. By summer, local aerosol sources, like boreal forest fire smoke, may come into prominence. Long term aerosol research from the University of Alaska Fairbanks indicates that the period around April typically marks the beginning of the retreat of the Polar Front, opening the free exchange of midlatitude air. In April 2008 the NASA ARCTAS field campaign was conducted, supported in Fairbanks by comprehensive polarization (0.693 μm) lidar, surface and balloon-borne aerosol measurements, and synoptic weather analyzes. The data provided information on the vertical distribution and type of aerosol, the size distributions and chemical nature of the surface aerosol, as well as the large scale view of aerosol transport conditions to Alaska. We found evidence to suggest four major aerosol loading events in the 25 March–30 April 2008 timeframe: a typical Arctic haze event, several days of extremely clear conditions, rapid onset of a period dominated by Asian dust with some smoke, and a period dominated by Asian smoke. A focused case study analysis conducted on 19 April 2008 using a balloon-borne optical particle counter suggested that, on this day, the majority of the suspended particulate matter consisted of Asian dust although a contribution from Asian smoke cannot be ruled out on the basis of backtrack analysis. In the last week of April concentrations gradually decreased as synoptic conditions shifted away from favoring transport to Alaska.
An Estimation of Angular Coordinates and Angular Distance of Two Moving Objects
by Using the Monopulse, MUSIC, and Root-MUSIC Methods
Authors: Rosloniec Wojciech
Published: June 2011

The paper presents results of extensive simulations carried out in order to assess the precision and angular resolution of subspace methods in real radar system. It has been assumed that such a system uses the 32-element uniform linear array (ULA) and radiates only 3 bursts consisting of 8 pulses in given direction. In order to avoid blind Doppler frequencies, pulse repetition interval (PRI) is different in each burst. It has been shown that change of PRI is not only necessary to avoid blind Doppler frequencies but also allows to avoid false values of angular coordinates when two objects are visible in the same beam, in the same range gate, and their echoes attain maximal values in the same Doppler filter. It has also been shown that precision and angular resolution of both MUSIC and root-MUSIC method can be improved by appropriate preprocessing of signal samples used by these methods.
Two Unusual Gastrointestinal Foreign Bodies
Authors: Al-Salem Ahmed H.
Published: June 2011

Swallowed foreign bodies are common in the pediatric age group, but fortunately, the majority of them pass spontaneously without any adverse effects. Tube gastrostomy is an excellent method to provide prolonged enteral feeding. It is, however, associated with complications, namely, intraperitoneal leak and distal migration of the gastrostomy tube causing gastric outlet obstruction. This paper describes two unusual gastrointestinal foreign bodies, one was swallowed, while the other one was a complication of a tube gastrostomy.
Cardiac Tumors
Authors: Paraskevaidis Ioannis A. , Michalakeas Christos A. , Papadopoulos Constantinos H. , Anastasiou-Nana Maria
Published: June 2011

Cardiac tumors represent a relatively rare, yet challenging diagnosis. Secondary tumors are far more frequent than primary tumors of the heart. The majority of primary cardiac tumors is benign in origin, with primary malignant tumors accounting for 25% of cases. Metastatic tumors usually arise from lung, breast, renal cancer, melanomas, and lymphomas. Clinical manifestations of cardiac tumors depend on the size and location of the mass and the infiltration of adjacent tissues rather than the type of the tumor itself. Echocardiography is the main diagnostic tool for the detection of a cardiac mass. Other imaging modalities (C-MRI, C-CT, 3D Echo) may offer further diagnostic information and the establishment of the diagnosis is made with histological examination. Management depends on the type of the tumor and the symptomatology of the patient.
Fast Implementation of the Subband Weighting for 3D Wavelet Coding
Authors: Peng Guan-Ju , Hwang Wen-Liang , Chen Sao-Jie
Published: June 2011

Performing optimal bit-allocation with 3D wavelet coding methods is difficult, because energy is not conserved after applying the motion-compensated temporal filtering (MCTF) process and the spatial wavelet transform. The problem has been solved by extending the 2D wavelet coefficients weighting method with the consideration of the complicated pixel connectivity resulting from the lifting-based MCTF process. However, the computation of weighting factors demands much computing time and vast amount of memory. In this paper, we propose a method, which facilitates the property of sparse matrices, to compute the subband weighing factors efficiently. The proposed method is employed for the 5–3 temporal filter and the 9–7 temporal filter in the lifting-based MCTF process. Experiments on various video sequences show that the computing time and memory needed for the computation of weighting factors are dramatically reduced by applying the proposed approach.
Prevalence of NAFLD in Healthy and Young Male Individuals
Authors: Niaz Asif , Ali Zafar , Nayyar Shaista , Fatima Naureen
Published: June 2011

Introduction. Nonalcoholic fatty liver disease (NAFLD) is an important cause of liver disease in adults and the most common cause of liver disease in children (Lavine and Schwimmer 2004). The abnormalities include increased liver fat without inflammation (steatosis) and nonalcoholic steatohepatitis (NASH). NASH may lead to fibrosis, cirrhosis, and ultimately liver failure if it is not treated (Matteoni et al. 1999). The objective of the study is to estimate the magnitude of the problem which will help us to formulate strategies in managing the potentially difficult problem. Materials and Methods. We included 1000 individuals between the ages of 30 and 50 years who came for annual checkup. The patients with other comorbidities like diabetes, ischemic heart disease, chronic liver disease, or renal diseases were excluded from the study. History of alcohol ingestion was also taken; any individual with history of alcohol intake was also excluded. All of them underwent investigations including CBC, LFTs, height and weight. The individuals who were found to have increased ALT (50 to 150 u/L) further underwent investigations including ultrasound of abdomen hepatitis b and c serology RA and ANA antibodies. All the individuals who were found to have viral or autoimmune illness were excluded from the study. The individuals having raised ALT levels and ultrasound evidence of fatty liver were taken. Results. 13.5% of the individuals were found to have NAFLD among those selected for the study. Conclusion. Mass campaign regarding physical and dietary measures needs to be undertaken in general masses regarding the gravity and potential prevention of the disease.
Antimicrobial Activity of Few Medicinal Plants against Clinically Isolated Human Cariogenic Pathogens—An In Vitro Study
Authors: Jebashree H. Shyla , Kingsley S. Jayasurya , Sathish Emmanuel S. , Devapriya D.
Published: June 2011

Hexane, ethyl acetate, ethanol and methanol extracts of
Psidium guajava, Terminalia chebula, Mimusops elengi and
Achyranthes aspera were tested against the dental caries
causing bacteria Streptococcus mutans and fungus
Candida albicans isolated from caries infected
patients. All the four extracts of P. guajava
showed activity against both S. mutans and
C. albicans. Maximum zone of inhibition was
observed in ethyl acetate of P. guajava. The four
extracts of T. chebula and M.
elengi showed antibacterial activity against S.
mutans. M. elengi extracts and ethanol
extract of T. chebula did not show any antifungal
activity against C. albicans. Except for the
hexane extract of A. aspera, the other three
extracts showed activity against the tested microbes. The ethyl
acetate P. guajava leaf extract showed the
minimum inhibitory concentration (MIC) against S.
mutans to be <0.076 mg/mL in both MHB and
BHI. The P. guajava ethyl acetate extract was
subjected to GC-MS.
Prolegomena for the Sociolinguistics of Classical Hebrew
Authors: Schniedewind William M.
Published: June 2011

The study of Classical Hebrew has largely proceeded from
the assumptions of 19th century neogrammarians as well as formalist approaches.
Their linguistic assumptions are based on the study of contemporary spoken
languages that and particularly ill-suited to deal with all the facets of an
ancient written language like Classical Hebrew. Language, and particularly
written language, is part of a cultural system. As such, the approaches in
sociolinguistics and anthropological linguistics need to integrated into the
study of Classical Hebrew.
Death, Social Conflict, and the Barley Harvest in the Hebrew
Bible
Authors: Britt Brian
Published: June 2011

Some recent scholarship characterizes violent biblical
narratives, such as the killing of Saul’s descendents in 2 Sam. 21, as evidence
of ancient ritual sacrifice. Yet 2 Sam. 21 has more in common with Ruth 1 and
Judith than with stories of sacrifice. By their common reference to the barley
harvest, untimely deaths, famine, and social conflict, these texts represent
reality through literary means. Drawing on René Girard’s theory of religion, I
suggest how the narratives of 2 Sam. 21, Ruth 1, and Judith, as well as a set of
narratives about sheepshearing, address social conflict as literary texts rather
than as transparent windows onto ancient practice.
Evidence Against Use of Nitrogen for the Death Penalty
Authors: Bickler Philip E. , Lipnick Michael S.
Published: May 2024

This Viewpoint discusses the recent use of forced nitrogen inhalation as capital punishment in Alabama and describes the body of evidence indicating that forced nitrogen inhalation is an inhumane practice.
The Balance Between Honesty and Hope
Authors: Godfrey Sarah
Published: May 2024

This essay describes the author’s experience as the mother of a newborn with a severe illness and the importance of balancing honesty and hope in delivering news to patients.
Enhancing diagnostic performance and image quality in coronary CT angiography: Impact of SnapShot Freeze 2 algorithm across varied heart rates in stent patients
Authors: Wu Zhehao , Han Qijia , Liang Yuying , Zheng Zhijuan , Wu Minyi , Ai Zhu , Ma Kun , Xiang Zhiming
Published: May 2024

Purpose

To investigate the enhancement of image quality achieved through the utilization of SnapShot Freeze 2 (SSF2), a comparison was made against the results obtained from the original SnapShot Freeze algorithm (SSF) and standard motion correction (STND) in stent patients undergoing coronary CT angiography (CCTA) across the entire range of heart rates.

Materials and methods

A total of 118 patients who underwent CCTA, were retrospectively included in this study. Images of these patients were reconstructed using three different algorithms: SSF2, SSF, and STND. Objective assessments include signal‐to‐noise ratio (SNR), contrast‐to‐noise ratio (CNR), diameters of stents and artifact index (AI). The image quality was subjectively evaluated by two readers.

Results

Compared with SSF and STND, SSF2 had similar or even higher quality in the parameters (AI, SNR, CNR, inner diameters) of coronary artery, stent, myocardium, MV (mitral valve), TV (tricuspid valve), AV (aorta valve), and PV (pulmonary valve), and aortic root (AO). Besides the above structures, SSF2 also demonstrated comparable or even higher subjective scores in atrial septum (AS), ventricular septum (VS), and pulmonary artery root (PA). Furthermore, the enhancement in image quality with SSF2 was significantly greater in the high heart rate group compared to the low heart rate group. Moreover, the improvement in both high and low heart rate groups was better in the SSF2 group compared to the SSF and STND group. Besides, when using the three algorithms, an effect of heart rate variability on stent image quality was not detected.

Conclusion

Compared to SSF and STND, SSF2 can enhance the image quality of whole‐heart structures and mitigate artifacts of coronary stents. Furthermore, SSF2 has demonstrated a significant improvement in the image quality for patients with a heart rate equal to or higher than 85 bpm.
Advanced Support Structures in Metal Additive Manufacturing: A Comparative Analysis of Porous Media for Enhanced Part Quality and Removal Efficiency
Authors: Erol Halil İbrahim , Gülletutan Umut Can , Günaydın Ahmet Can , Altınok Sertaç , Yavaş Hakan , Salamci Metin Uymaz
Published: May 2024

In laser powder bed fusion additive manufacturing support, structures are crucial for constructing overhang features and maintaining dimensional accuracy. However, traditional support structures exhibit inherent drawbacks, including compromised surface quality, prolonged postprocessing times, and other challenging requirements. This study investigates innovative approaches to address these issues by analyzing two types of specimens—cuboid and lap shear. The cuboid samples explore the manipulation of process parameters to adjust energy densities, transitioning from powder to porous support structures, with porosity measurement assessment. Subsequently, a shear test specimen objectively evaluates porous support parameters alongside traditional block‐type support, analyzing their impact on removal force, distortion, and surface quality. Results reveal that optimized porous support structures surpass traditional counterparts, showcasing superior surface quality, reduced removal forces, and minimized part distortion. Specifically, the shear test demonstrates a 94.25% reduction in removal forces and a 33.67% decrease in upper part distortion. Moreover, the maximum surface roughness (Rz) improves by 22.8% with the implementation of porous supports. By introducing a methodology for comparative analyses of measurable performance indicators, this research enhances understanding of support structure dynamics in additive manufacturing, facilitating advancements in efficiency and quality within the field.
Improved Thermoelectric Performance in Ga‐ and Te‐Co‐introduced Tetrahedrite Cu12Sb4S13
Authors: Yang Chao , Qu Luping , Wang Pengjun , Li Shiye , Wang Jie , Zhu Baoshun , Cheng Shixing , Jiang Shuyin , Xing Baolin , Cui Jiaolin
Published: May 2024

As an earth‐abundant, environment‐friendly, and cost‐effective material, tetrahedrite Cu12Sb4S13 has attracted much attention in thermoelectrics (TEs). However, the TE performance of the pristine Cu12Sb4S13 (CSS) is mediocre, thereby much improvement is required. In this work, both the electronic and phonon transports of the CSS are engineered using Ga2Te3 as a dopant. In the results, it is indicated that dual substitutions of Ga for Cu and Te for Sb not only cause the enhancement of power factor via electronic band structure tuning, but also leads to a drop in both the electronic and lattice thermal conductivities. As a result, the total thermal conductivity (κ) decreases to 0.98 W m−1 K−1 at 770 K, which is about 58% that of the pristine CSS, thus improving the TE performance with the highest dimensionless figure of merit value increasing to 0.95 for (Cu12Sb4S13)0.9(Ga2Te3)0.1 at 773 K, 1.9 times that of the pristine CSS (≈0.5 at 770 K).
Investigation of the Elevated Temperature Tribological Property and Wear Mechanism of Fe–15Cu–0.8C Materials Containing Mo‐Coated MoS2Powders
Authors: Li Jiaxin , Chen Zhipeng , Shu Yunxiang , Zhang Jianhua , Cheng Jigui
Published: May 2024

Herein, MoS2solid lubricant is introduced in the form of Mo‐coated MoS2powder, to enhance the antifriction properties of sintered ferrous antifriction materials (FAMs). The microstructure, phase composition, and tribological properties of Fe–15Cu–0.8C–3.75 (Mo‐coated MoS2) (MC1) are investigated and compared with Fe–15Cu–0.8C (M0) samples, with a discussion on the wear mechanism at a wide temperature range of room temperature to 600 °C. The study reveals that the addition of Mo‐coated MoS2powders effectively prevents the decomposition of MoS2during sintering, enhances the bonding strength between MoS2and the substrate, and significantly improves the hardness of the sintered Fe–15Cu–0.8C samples. In comparison with the sintered Fe–15Cu–0.8C samples, the sintered Fe–15Cu–0.8C–3.75 (Mo‐coated MoS2) samples exhibit good antifriction properties with a frictional coefficient of 0.23 at 600 °C and a wear rate of 6.3 × 10−7mm3N m−1at 300 °C. Introducing Mo‐coated MoS2significantly reduces the average friction coefficient and wear rate of the sintered FAMs at elevated temperatures, attributed to the formation of FeMoO4. The antifriction performance of MC1 samples notably decreases with increasing test temperatures. The main wear mechanism is oxidative wear above 300 °C.
Robust Phototaxis by Harnessing Implicit Communication in Modular Soft Robotic Systems
Authors: Schomaker H. A. H. , Picella S. , Küng Garcia A. , van Laake L. C. , Overvelde J. T. B.
Published: May 2024

In robotics, achieving adaptivity in complex environments is challenging. Traditional robotic systems use stiff materials and computationally expensive centralized controllers, while nature often favors soft materials and embodied intelligence. Inspired by nature's distributed intelligence, this study explores a decentralized approach for robust behavior in soft robotic systems without knowledge of their shape or environment. It is demonstrated that only a few basic rules implemented in identical modules that shape the soft robotic system can enable whole‐body phototaxis, navigating on a surface toward a light source, without explicit communication between modules or prior system knowledge. The results reveal the method's effectiveness in generating robust and adaptive behavior in dynamic and challenging environments. Moreover, the approach's simplicity makes it possible to illustrate and understand the underlying mechanism of the observed behavior, paying particular attention to the geometry of the assembled system and the effect of learning parameters. Consequently, the findings offer insights into the development of adaptive, autonomous robotic systems with minimal computational power, paving the way for robust and useful behavior in soft and microscale robots, as well as robotic matter, that operate in real‐world environments.
Integrated Textile Supercapacitors Enhanced with Energy‐Absorbing Spacer Fabrics and Ti3C2Tx MXene
Authors: Zhang Peng , Wang Zhiyu , Zhang Hongjie , Usman Ken Aldren , Hegh Dylan , Chen Shasha , Yang Fangli , Zhong Zhili , Naebe Maryam , Wang Xungai , Qin Si , Razal Joselito M.
Published: May 2024

The rapid development of wearable electronics requires energy storage devices capable of withstanding both static and dynamic deformations. The versatility of textile supercapacitors renders them promising candidates, but their low electrochemical performance especially under mechanical deformation, poses many limitations for practical use. In this study, MXene‐based textile supercapacitors are designed and fabricated using hierarchical spacer fabrics as the skeleton to provide robust mechanical support and stable performance. Ti3C2Tx MXene is adopted as the current collector and active material for the spacer fabric supercapacitor, resulting in an impressive areal capacitance of 415 mF cm−2 with a MXene loading of 4.2 mg cm−2. Remarkable stability and durability are achieved in the form of three‐dimensional (3D) textile supercapacitors, even under both static and dynamic deformations. The compressive behaviors of these supercapacitors can be easily adjusted (e.g., from 10 to 168 KPa at 50% compression) by altering the spacer fabric structure, demonstrating their energy‐absorption (damping of kinetic energy) capability and their potential to meet the requirements of various wearable applications.
Modeling Charged Defects Using the Defect Energy Formalism With a Charge Sublattice Within a CALPHAD Framework
Authors: Adekoya Adetoye H. , Snyder G. Jeffrey
Published: May 2024

The non‐stoichiometry of material compounds significantly influences their functional properties. In semiconductors, point defects determine whether a material is n‐type or p‐type and the concentration of charge carriers. Even in structural alloys and ion conductors used in batteries and fuel cells, non‐stoichiometry and dilute defects play an integral role in their function. The design of metal alloys has advanced rapidly with the aid of thermodynamic modeling using calculation of phase diagrams (CALPHAD) to predict the phases produced during different processing conditions. While thermodynamic modeling has been done previously by fitting experimental data, the advent of first‐principle techniques has enabled the computational prediction of material properties. The defect energy formalism (DEF) is described for modeling charged and uncharged defects in compounds, showing that it accurately predicts non‐stoichiometry using density functional theory (DFT), without fitting experiments. The model reproduces the expected defect and free‐charge carrier concentrations using the statistical mechanics approach commonly used in most DFT defect studies. Finally, the model is used to accurately predict the single‐phase region of PbTe with no fitting to measured defect concentrations. This method can revolutionize materials development of insulators, semiconductors, and even metals by allowing rapid DFT calculations to replace laborious experiments when dilute defects are involved.
Au/FeNiPO4‐Based Multiple Spectra Optoacoustic Tomography/CT Dual‐Mode Nanoprobe for Systemic Screening of Atherosclerotic Vulnerable Plaque
Authors: Cai Jiageng , Ge Xiaoxiao , Lu Shiyu , Wang Yabin , Cui Hongtu , Zhan Rui , Su Sheng'e , Shan Wenxin , Cai Zhulan , Wu Cencen , Xu Yuan , Zhao Penghui , Li Yanyan , Lan Yue , Sun Le , Guo Shaojun , Zheng Lemin , Zu Lingyun
Published: May 2024

Current diagnostic technique in direct identification of multi‐site plaques and simultaneous assessment of plaque vulnerability remains a challenge, which is crucial for indicating the risk of atherosclerotic cardiovascular diseases (ASCVD). Herein, an osteopontin (OPN)‐specific nanoprobe (OPN Ab‐Au/FeNiPO4@ICG) with both multiple spectra optoacoustic tomography (MSOT) and computed tomography (CT) imaging, is constructed successfully realizing systemic screening of vulnerable plaque. OPN Ab‐Au/FeNiPO4@ICG nanoprobe specifically targeted OPN‐overexpressed foam cells and recognized the vulnerable plaque at the molecular level. In AS mice, CT imaging exhibits that OPN Ab‐Au/FeNiPO4@ICG nanoprobe effectively avoid interference from calcification and accurately visualized AS plaque. MSOT functional imaging results reveals that after the injection of OPN Ab‐Au/FeNiPO4@ICG nanoprobe, the carotid plaque exhibited a much higher MSOT signal than the aortic arch plaque (P = 0.0291). Further pathological analysis displays that the carotid plaque possessed a much higher vulnerability score (P = 0.0247), in agreement with the MSOT signals. More importantly, the linear regression analysis confirms the high correlation between the MSOT signals and plaque vulnerability with R = 0.7095 (P = 0.0216), demonstrating the potential of the proposed nanoprobe in systematic evaluation of plaque vulnerability. This work employs the dual‐model nanoprobe strategy for both plaque localization and vulnerability assessment, greatly advancing the accurate diagnosis of ASCVD.
Granular Biomaterials as Bioactive Sponges for the Sequestration and Release of Signaling Molecules
Authors: Emiroglu Dilara Börte , Singh Apoorv , Marco‐Dufort Bruno , Speck Noël , Rivano Pier Giuseppe , Oakey John S. , Nakatsuka Nako , deMello Andrew J. , Labouesse Céline , Tibbitt Mark W.
Published: May 2024

A major challenge for the regeneration of chronic wounds is an underlying dysregulation of signaling molecules, including inflammatory cytokines and growth factors. To address this, it is proposed to use granular biomaterials composed of jammed microgels, to enable the rapid uptake and delivery of biomolecules, and provide a strategy to locally sequester and release biomolecules. Sequestration assays on model biomolecules of different sizes demonstrate that granular hydrogels exhibit faster transport than comparable bulk hydrogels due to enhanced surface area and decreased diffusion lengths. To demonstrate the potential of modular granular hydrogels to modulate local biomolecule concentrations, microgel scaffolds are engineered that can simultaneously sequester excess pro‐inflammatory factors and release pro‐healing factors. To target specific biomolecules, microgels are functionalized with affinity ligands that bind either to interleukin 6 (IL‐6) or to vascular endothelial growth factor A (VEGF‐A). Finally, disparate microgels are combined into a single granular biomaterial for simultaneous sequestration of IL‐6 and release of VEGF‐A. Overall, the potential of modular granular hydrogels is demonstrated to locally tailor the relative concentrations of pro‐ and anti‐inflammatory factors.
Paracrine Ovarian Cancer Cell‐Derived CSF1 Signaling Regulates Macrophage Migration Dynamics in a 3D Microfluidic Model that Recapitulates In Vivo Infiltration Patterns in Patient‐Derived Xenografts
Authors: Scott Alexis L. , Jazwinska Dorota E. , Kulawiec Diana G. , Zervantonakis Ioannis K.
Published: May 2024

A high density of macrophages in the ovarian cancer microenvironment is associated with disease progression and poor outcomes. Understanding cancer‐macrophage interaction mechanisms that establish this pro‐tumorigenic microenvironment is critical for developing macrophage‐targeted therapies. Here, 3D microfluidic assays and patient‐derived xenografts are utilized to define the role of cancer‐derived colony stimulating factor 1 (CSF1) on macrophage infiltration dynamics toward ovarian cancer cells. It is demonstrated that multiple ovarian cancer models promote the infiltration of macrophages into a 3D extracellular matrix in vitro in a cell density‐dependent manner. Macrophages exhibit directional migration and increased migration speed under both direct interactions with cancer cells embedded within the matrix and paracrine crosstalk with cancer cells seeded in an independent microchannel. It is also found that platinum‐based chemotherapy increases macrophage recruitment and the levels of cancer cell‐derived CSF1. Targeting CSF1 signaling under baseline or chemotherapy‐treatment conditions reduces the number of infiltrated macrophages. It is further shown that results obtained with the 3D microfluidic model reflect the recruitment profiles of macrophages in patient‐derived xenografts in vivo. These findings highlight the role of CSF1 signaling in establishing macrophage‐rich ovarian cancer microenvironments, as well as the utility of microfluidic models in recapitulating 3D tumor ecosystems and dissecting cancer‐macrophage signaling.
Electrolytes for Sodium Ion Batteries: The Current Transition from Liquid to Solid and Hybrid systems
Authors: Darjazi Hamideh , Falco Marisa , Colò Francesca , Balducci Leonardo , Piana Giulia , Bella Federico , Meligrana Giuseppina , Nobili Francesco , Elia Giuseppe A. , Gerbaldi Claudio
Published: May 2024

Sodium‐ion batteries (NIBs) have recently garnered significant interest in being employed alongside conventional lithium‐ion batteries, particularly in applications where cost and sustainability are particularly relevant. The rapid progress in NIBs will undoubtedly expedite the commercialization process. In this regard, tailoring and designing electrolyte formulation is a top priority, as they profoundly influence the overall electrochemical performance and thermal, mechanical, and dimensional stability. Moreover, electrolytes play a critical role in determining the system's safety level and overall lifespan. This review delves into recent electrolyte advancements from liquid (organic and ionic liquid) to solid and quasi‐solid electrolyte (dry, hybrid, and single ion conducting electrolyte) for NIBs, encompassing comprehensive strategies for electrolyte design across various materials, systems, and their functional applications. The objective is to offer strategic direction for the systematic production of safe electrolytes and to investigate the potential applications of these designs in real‐world scenarios while thoroughly assessing the current obstacles and forthcoming prospects within this rapidly evolving field.
Fully 3D‐Printed Miniature Soft Hydraulic Actuators with Shape Memory Effect for Morphing and Manipulation
Authors: Qing Haitao , Chi Yinding , Hong Yaoye , Zhao Yao , Qi Fangjie , Li Yanbin , Yin Jie
Published: May 2024

Miniature shape‐morphing soft actuators driven by external stimuli and fluidic pressure hold great promise in morphing matter and small‐scale soft robotics. However, it remains challenging to achieve both rich shape morphing and shape locking in a fast and controlled way due to the limitations of actuation reversibility and fabrication. Here, fully 3D‐printed, sub‐millimeter thin‐plate‐like miniature soft hydraulic actuators with shape memory effect (SME) for programable fast shape morphing and shape locking, are reported. It combines commercial high‐resolution multi‐material 3D printing of stiff shape memory polymers (SMPs) and soft elastomers and direct printing of microfluidic channels and 2D/3D channel networks embedded in elastomers in a single print run. Leveraging spatial patterning of hybrid compositions and expansion heterogeneity of microfluidic channel networks for versatile hydraulically actuated shape morphing, including circular, wavy, helical, saddle, and warping shapes with various curvatures, are demonstrated. The morphed shapes can be temporarily locked and recover to their original planar forms repeatedly by activating SME of the SMPs. Utilizing the fast shape morphing and locking in the miniature actuators, their potential applications in non‐invasive manipulation of small‐scale objects and fragile living organisms, multimodal entanglement grasping, and energy‐saving manipulators, are demonstrated.
Tandem Fields Facilitating Directional Carrier Migration in Van der Waals Heterojunction for Efficient Overall Piezo‐Synthesis of H2O2
Authors: Xu Jing , Che Huinan , Tang Chunmei , Liu Bin , Ao Yanhui
Published: May 2024

Piezo‐synthesis of H2O2 utilizing sustainable mechanical energy as well as earth‐abundant water and oxygen is a green, cost‐effective, and promising approach. However, achieving simultaneous two‐electron water oxidation reaction (2e− WOR) and two‐electron oxygen reduction reaction (2e− ORR) faces huge challenges due to insufficient synergistic active sites and slow/messy carrier transfer. Herein, a novel 2D/2D van der Waals heterojunction consisting of BiOIO3 and carbon nitride (BIO/CN) is elaborately designed for highly efficient overall H2O2 piezo‐synthesis. Theoretical/experimental results reveal that a Z‐scheme electron transfer is formed and facilitated by the tandem interfacial electric field and the bulk piezo‐polarization field. On this basis, the carriers are efficiently separated while the oxidation/reduction capacity is preserved, thus providing the strong driving force for the 2e− WOR and 2e− ORR on BIO and CN, respectively. Furthermore, the kinetic and thermodynamic processes of WOR and ORR for H2O2 synthesis improve remarkably. Therefore, BIO/CN exhibits an excellent H2O2 yield of 259.8 µM within 30 min in pure water and air atmosphere (without any sacrificial agents and aeration). This study provides a new idea on strategically controlling electron transfer toward high‐efficiency H2O2 piezo‐synthesis and expands the avenue for developing effective environmental purification materials.
Laser‐Scribed Battery Electrodes for Ultrafast Zinc‐Ion Energy Storage
Authors: Liu Bo , Huang Ailun , Yuan Xintong , Chang Xueying , Yang Zhiyin , Lyle Katelyn , Kaner Richard B. , Li Yuzhang
Published: May 2024

Aqueous Zn batteries are promising for large‐scale energy storage but are plagued by the lack of high‐performance cathode materials that enable high specific capacity, ultrafast charging, and outstanding cycling stability. Here, a laser‐scribed nano‐vanadium oxide (LNVO) cathode is designed that can simultaneously achieve these properties. The material stores charge through Faradaic redox reactions on/near the surface at fast rates owing to the small grain size of vanadium oxide and interpenetrating 3D graphene network, displaying a surface‐controlled capacity contribution (90%–98%). Multiple characterization techniques unambiguously reveal that zinc and hydronium ions co‐insert with minimal lattice change upon cycling. It is demonstrated that a high specific capacity of 553 mAh g−1 is achieved at 0.1 A g−1, and an impressive 264 mAh g−1 capacity is retained at 100 A g−1 within 10 s, showing excellent rate capability. The LNVO/Zn can also reach >90% capacity retention after 3000 cycles at a high rate of 30 A g−1, as well as achieving both high energy (369 Wh kg−1) and power densities (56306 W kg−1). Moreover, the LNVO cathode retains its excellent cycling performance when integrated into quasi‐solid‐state pouch cells, further demonstrating mechanical stability and its potential for practical application in wearable and grid‐scale applications.
From Fundamental Interfacial Reaction Kinetics to Macroscopic Current–Voltage Characteristics: Case Study of Solid Acid Fuel Cell Limitations and Possibilities
Authors: Wang Louis S. , Haile Sossina M.
Published: May 2024

The unique properties of solid acid electrolytes, in particular CsH2PO4, are in many ways ideal for fuel cell operation. However, the technology is constrained by high cathode overpotentials. Here a simplified cathode geometry is employed to obtain the fundamental electrochemical parameters (exchange current density and charge transfer coefficient) describing the oxygen reduction reaction (ORR) at the CsH2PO4‐Pt‐gas interface. The parameters are incorporated into a 1D model of the voltage–current characteristics of realistic SAFC cathodes, which reproduced the measured polarization behavior of such cathodes without recourse to fitting adjustable parameters. Following this validation, the model is utilized to evaluate the impact of changes to cathode properties, microstructure, and operating conditions. Of these, the charge transfer coefficient, measured to have a value of ≈0.6 for ORR on Pt in the SAFC cathode environment, is found to have the greatest impact on power output. Nevertheless, even without material modifications, a combination of microstructural and operational modifications are identified with projected performance metrics meeting Department of Energy targets (0.8 V at 300 mA cm−2, and peak power density of 1 W cm−2), albeit at high Pt loadings. However, the analysis indicates that truly meaningful advances will likely necessitate the discovery of alternative ORR catalysts.