bluuebunny/crossref_metadata_2025 huggingface dataset:
One-step immunoassay for the detection of food-poisoning related bacteria using a switching peptide
Authors: Lee Chang Kyu , Jung Jaeyong , Kim Hong-Rae , Bong Ji-Hong , Kim Tae-Hun , Park Jun-Hee , Kwon Soonil , Kang Min-Jung , Pyun Jae-Chul
Published: September 2022

A one-step immunoassay was developed for detecting five types of food-poisoning-related bacteria using a switching peptide and antibodies isolated from unimmunized horse serum.
Rapid and sensitive SARS-CoV-2 detection using a homogeneous fluorescent immunosensor Quenchbody with crowding agents
Authors: Zhu Bo , Nosaka Nobuyuki , Kanamaru Shuji , Dong Jinhua , Dai Yancen , Inoue Akihito , Yang Yinghui , Kobayashi Kaori , Kitaguchi Tetsuya , Iwasaki Hiroshi , Koike Ryuji , Wakabayashi Kenji , Ueda Hiroshi
Published: September 2022

A Quenchbody immunosensor for SARS-CoV-2 nucleocapsid protein was developed, and 5% PEG6000 significantly improved its response speed and sensitivity. Positive and negative groups of COVID-19 clinical samples were distinguished.
DNAzyme-powered cascade DNA walkers for sensitive detection of uracil DNA glycosylase activity
Authors: Yang Yayun , Zhang Liyan , Jiang Dafeng , Zhang Nan , Jiang Wei
Published: September 2022

A DNAzyme-powered cascade DNA walker has been developed for sensitive detection of uracil DNA glycosylase activity.
A signal on–off strategy based on the digestion of DNA cubes assisted by the CRISPR–Cas12a system for ultrasensitive HBV detection in solid-state nanopores
Authors: Wang Jiahai , Luo Le , Li Yunhui , Chen Lanfang , Gui Cenlin , Zhu Jianji , Li Huizhen , Wang Wenlong , Chen Daqi
Published: September 2022

A sensing strategy for the ultrasensitive detection of HBV in nanopores was constructed by digestion of elements of DNA cubes and the use of CRISPR–Cas12a technology. Coupling with PCR preamplification technology enabled HBV-positive or -negative classification.
Deracemisation and stereoinversion by a nanoconfined bidirectional enzyme cascade: dual control by electrochemistry and selective metal ion activation
Authors: Cheng Beichen , Heath Rachel S. , Turner Nicholas J. , Armstrong Fraser A. , Megarity Clare F.
Published: September 2022

Enzymes nanoconfined in a porous electrode are electrochemically driven for deracemisation and inversion with additional control by metal ion activation.
Insights into the stability of magnesium borate salts for rechargeable magnesium batteries from AIMD simulations
Authors: Zhang Shuxin , Cheng Mingxiang , Zhang Peng , Wang Yaru , Zhang Duo , Yang Yang , Wang Jiulin , NuLi Yanna
Published: September 2022

We present AIMD simulations for the stability of boron-center salts, Mg[B(Ohfip)4]2 and Mg[B(Otfe)4]2, compared to Mg(TFSI)2, and provide a visible reaction process at the atomic level.
Modulation of transport properties via S/Br substitution: solvothermal synthesis, crystal structure, and transport properties of Bi13S17Br3
Authors: Amarasinghe Dinesh K. , Yox Philip , Viswanathan Gayatri , Adeyemi Adedoyin N. , Kovnir Kirill
Published: September 2022

The synthesis, formation mechanism, crystal structure, and transport properties of the bismuth chalcohalide Bi13S17Br3 are reported.
Invisible strings. The first single crystal of the cTSAP form of [Eu(DOTA)(H2O)]− has an electronic structure similar to one of the reported cSAP forms
Authors: Storm Thomsen Maria , Parsons Simon , Sørensen Thomas Just
Published: September 2022

Counter ions can be used to tune the solid state structure of Eu·DOTA between the cSAP and cTSAP form, but the electronic properties does not match the observations seen in solution.
An anodeless, mechanically flexible and energy/power dense sodium battery prototype
Authors: Bai Miao , Tang Xiaoyu , Liu Siyuan , Wang Helin , Liu Yujie , Shao Ahu , Zhang Min , Wang Zhiqiao , Ma Yue
Published: September 2022

An enabling anode-less sodium metal battery design was proposed by encapsulating various zinc-containing multialloys (from ternary to medium/high entropy alloys) within the interweaved carbon nanotubes as the lightweight, mechanical-flexible Na deposition substrates.
On-demand continuous H2 release by methanol dehydrogenation and reforming via photocatalysis in a membrane reactor
Authors: Jiao Haimiao , Yang Jianlong , Li Xiyi , Wang Chao , Tang Junwang
Published: September 2022

A robust flow membrane reactor is established and utilised for efficient green H2 production in photocatalytic methanol dehydrogenation and reforming, benefiting from its enhanced mass transfer and effective charge separation in the catalysts.
Recent advances in high-throughput single-cell transcriptomics and spatial transcriptomics
Authors: Shen Xiaohan , Zhao Yichun , Wang Zhuo , Shi Qihui
Published: September 2022

We review technological spectrum and advances in high-throughput single-cell transcriptomics and spatial transcriptomics, discuss their advantages and limitations, and pitch into new biology learned from these new tools.
Imidazole encapsulated in core–shell MOF@COFs with a high anhydrous proton conductivity
Authors: Liu Shucheng , Li Han , Shuai Yu , Ding Zhao , Liu Yi
Published: September 2022

A novel core–shell imidazole@MOF@COF proton conductor is constructed using UiO-67 and TAPB-DMTP-COFs.
g-C3N4/dendritic fibrous nanosilica doped with potassium for photocatalytic CO2 reduction
Authors: Rawool Sushma A. , Kar Yusuf , Polshettiwar Vivek
Published: September 2022

The preferential reduction of CO2 over water to generate methane by potassium ion doping into the matrix of g-C3N4/DFNS.
Recent progress in one dimensional TiO2nanomaterials as photoanodes in dye-sensitized solar cells
Authors: Joshy Deepak , Narendranath Soumya B. , Ismail Yahya A. , Periyat Pradeepan
Published: September 2022

One-dimensional TiO2nanomaterials as efficient DSSC photoanode materials.
Contribution of antioxidant action of 7-chloro-4-(phenylselanyl)quinoline to treat streptozotocin-induced diabetic neuropathy in mice
Authors: Voss Guilherme T. , de Oliveira Renata L. , do Sacramento Manoela , Roehrs Juliano Alex , Alves Diego , Luchese Cristiane , Wilhelm Ethel A.
Published: September 2022

4-PSQ reduced mechanical and thermal hypersensitivities of diabetic mice by modulation of oxidative stress and glycemic levels.
Microwave-assisted catalyst-free multicomponent one-pot green synthesis of highly functionalized aminocyanopyridines and (4-hydroxy)quinolines in aqueous medium and its in silico studies
Authors: Kumar Loveneesh , Verma Nishant , Kumar Neeraj , Sehrawat Hitesh , Kumar Rupesh , Chandra Ramesh
Published: September 2022

Microwave-assisted catalyst-free green synthesis of aminocyanopyridines and (4-hydroxy)quinolines along with the speciality of the system and binding of the lead drug.
Evaluation and optimization of the thermal conductivity enhancement of a water-based GO nanosheets/Au NPs hybrid nanofluid: Box-Behnken design
Authors: Dastnaei Amin , Behbahani Mohammad , Pourrajab Rashid , Noghrehabadi Aminreza
Published: September 2022

In this work, a decorated graphene oxide with gold nanoparticle (GO/Au NP)/water hybrid nanofluid was prepared as an efficient hybrid nanofluid for thermal conductivity enhancement. The impact of essential parameters on the enhancement of the thermal conductivity was optimized using the Box-Behnken design.
The composing effect of bismuth on titania hollow microspheres for their visible-light photocatalytic activity
Authors: Han Yimin , Wang Bo , Xiang Quanjun , Li Wensheng
Published: September 2022

Bi-composed TiO2 hollow microspheres with enhanced visible-light photocatalytic activity are prepared by an impregnation–calcination method.
Metal-free visible-light-driven cascade cyclization reaction to synthesize 2-oxindoles via benzoyl and phenylsulfinyl radicals with acrylamide derivatives
Authors: Sun Xin , Zhu Jing-Ping , Qiu Qing-Chuang , He Ya-Li , Hu Da-Rong , Li Xin-Ling , Lu Gui-Ping , Yuan Ying-Hui , Zhang Xiang-Fei , Xu Xiaobo , Yu Miao , Wu Bin
Published: September 2022

A metal-free visible-light-driven cascade cyclization reaction to synthesize 3-methyl-3-acetophenone-2-oxindoles and 3-methyl-3-(methylsulfonyl)benzene-2-oxindoles via benzoyl and phenylsulfinyl radicals has been reported.
TESS discovery of a super-Earth and two sub-Neptunes orbiting the bright, nearby, Sun-like star HD 22946
Authors: Cacciapuoti Luca , Inno Laura , Covone Giovanni , Kostov Veselin B. , Barclay Thomas , Quintana Elisa V. , Colon Knicole D. , Stassun Keivan G. , Hord Benjamin , Giacalone Steven , Kane Stephen R. , Hoffman Kelsey , Rowe Jason , Wang Gavin , Collins Kevin I. , Collins Karen A. , Tan Thiam-Guan , Gallo Francesco , Magliano Christian , Ienco Riccardo M. , Rabus Markus , Ciardi David R. , Furlan Elise , Howell Steve B. , Gnilka Crystal L. , Scott Nicholas J. , Lester Kathryn V. , Ziegler Carl , Briceño César , Law Nicholas , Mann Andrew W. , Burke Christopher J. , Quinn Samuel N. , Ciaramella Angelo , De Luca Pasquale , Fiscale Stefano , Rotundi Alessandra , Marcellino Livia , Galletti Ardelio , Bifulco Ida , Oliva Fabrizio , Spencer Alton , Kaltenegger Lisa , McDermott Scott , Essack Zahra , Jenkins Jon M. , Wohler Bill , Winn Joshua N. , Seager S. , Vanderspek Roland , Zhou George , Shporer Avi , Dragomir Diana , Fong William
Published: September 2022

We report the Transiting Exoplanet Survey Satellite (TESS) discovery of a three-planet system around the bright Sun-like star HD 22946 (V ≈ 8.3 mag), also known as TIC 100990000, located 63 pc from Earth. The system was observed by TESS in Sectors 3, 4, 30, and 31 and two planet candidates, labeled TESS Objects of Interest (TOIs) 411.01 (planet c) and 411.02 (planet b), were identified on orbits of 9.57 and 4.04 days, respectively. In this work, we validate the two planets and recover an additional single transit-like signal in the light curve, which suggests the presence of a third transiting planet with a longer period of about 46 days. We assess the veracity of the TESS transit signals and use follow-up imaging and time-series photometry to rule out false-positive scenarios, including unresolved binary systems, nearby eclipsing binaries, and contamination of the light curves by background or foreground stars. Parallax measurements from Gaia Early Data Release 3 together with broad-band photometry and spectroscopic follow-up by the TESS FollowUp Observing Program (TFOP) allowed us to constrain the stellar parameters of TOI-411, including its radius of 1.157 ± 0.025 R⊙. Adopting this value, we determined the radii for the three exoplanet candidates and found that planet b is a super-Earth with a radius of 1.48 ± 0.06 R⊕, while planets c and d are sub-Neptunian planets with radii of 2.35 ± 0.08 R⊕ and 2.78 ± 0.13 R⊕ respectively. Using dynamical simulations, we assessed the stability of the system and evaluated the possibility of the presence of other undetected, non-transiting planets by investigating its dynamical packing. We find that the system is dynamically stable and potentially unpacked, with enough space to host at least one more planet between c and d. Finally, given that the star is bright and nearby, we discuss possibilities for detailed mass characterisation of its surrounding worlds and opportunities for the detection of their atmospheres with the James Webb Space Telescope.
Characterising the AGB bump and its potential to constrain mixing processes in stellar interiors
Authors: Dréau G. , Lebreton Y. , Mosser B. , Bossini D. , Yu J.
Published: September 2022

Context. In the 1990s, theoretical studies motivated the use of the asymptotic giant branch bump (AGBb) as a standard candle given the weak dependence between its luminosity and stellar metallicity. Because of the small size of observed asymptotic giant branch (AGB) samples, detecting the AGBb is not an easy task. However, this has now been made possible thanks to the wealth of data collected by the CoRoT, Kepler, and TESS space-borne missions.

Aims. It is well-known that the AGB bump provides valuable information on the internal structure of low-mass stars, particularly on mixing processes such as core overshooting during the core He-burning phase. Here, we investigate the dependence of the AGBb position on stellar parameters such as the stellar mass and metallicity based on the calibration of stellar models to observations.

Methods. In this context, we analysed ∼4000 evolved giants observed by Kepler and TESS, including red giant branch (RGB) stars and AGB stars, for which asteroseismic and spectrometric data are available. By using statistical mixture models, we detected the AGBb both in frequency at maximum oscillation power, νmax, and in effective temperature, Teff. Then, we used the Modules for Experiments in Stellar Astrophysics (MESA) stellar evolution code to model AGB stars and match the AGBb occurrence with observations.

Results. From the observations, we were able to derive the AGBb location in 15 bins of mass and metallicity. We noted that the higher the mass, the later the AGBb occurs in the evolutionary track, which agrees with theoretical works. Moreover, we found a slight increase in the luminosity at the AGBb when the metallicity increases. By fitting those observations with stellar models, we noticed that low-mass stars (M ≤ 1.0 M⊙) require a small core overshooting region during the core He-burning phase. This core overshooting extent increases toward high mass; however, above M ≥ 1.5 M⊙, we found that the AGBb location cannot be reproduced with a realistic He-core overshooting alone. Thus, additional mixing processes have to be invoked instead.

Conclusions. The observed dependence on metallicity complicates the application of the AGBb as a standard candle. Moreover, different mixing processes may occur according to stellar mass. At low mass (M ≤ 1.5 M⊙), the AGBb location can be used to constrain the He-core overshooting. At high mass (M ≥ 1.5 M⊙), an additional mixing induced, for instance, by rotation is needed to reproduce what is seen in observations.
Tilting Uranus via the migration of an ancient satellite
Authors: Saillenfest Melaine , Rogoszinski Zeeve , Lari Giacomo , Baillié Kevin , Boué Gwenaël , Crida Aurélien , Lainey Valéry
Published: September 2022

Context. The 98° obliquity of Uranus is commonly attributed to giant impacts that occurred at the end of the planetary formation. This picture, however, is not devoid of weaknesses.

Aims. On a billion-year timescale, the tidal migration of the satellites of Jupiter and Saturn has been shown to strongly affect their spin-axis dynamics. We aim to revisit the scenario of tilting Uranus in light of this mechanism.

Methods. We analyse the precession spectrum of Uranus and identify the candidate secular spin-orbit resonances that could be responsible for the tilting. We determine the properties of the hypothetical ancient satellite required for a capture and explore the dynamics numerically.

Results. If it migrates over 10 Uranus’s radii, a single satellite with minimum mass 4 × 10−4 Uranus’s mass is able to tilt Uranus from a small obliquity and make it converge towards 90°. In order to achieve the tilting in less than the age of the Solar System, the mean drift rate of the satellite must be comparable to the Moon’s current orbital expansion. Under these conditions, simulations show that Uranus is readily tilted over 80°. Beyond this point, the satellite is strongly destabilised and triggers a phase of chaotic motion for the planet’s spin axis. The chaotic phase ends when the satellite collides into the planet, ultimately freezing the planet’s obliquity in either a prograde or a plainly retrograde state (as Uranus today). Spin states resembling that of Uranus can be obtained with probabilities as large as 80%, but a bigger satellite is favoured, with mass 1.7 × 10−3 Uranus’s mass or more. Yet, a smaller ancient satellite is not categorically ruled out, and we discuss several ways to improve this basic scenario in future studies. Interactions among several pre-existing satellites are a promising possibility.

Conclusions. The conditions required for the tilting seem broadly realistic, but it remains to be determined whether Uranus could have hosted a big primordial satellite subject to substantial tidal migration. The efficiency of tidal energy dissipation within Uranus is required to be much higher than traditionally assumed, more in line with that measured for the migration of Titan. Hints about these issues would be given by a measure of the expansion rate of Uranus’s main satellites.
Portable Resistive Plate Chambers for Muography in confined environments
Authors: Gamage R.M.I.D , Basnet Samip , Cortina Gil Eduardo , Giammanco Andrea , Demin Pavel , Moussawi Marwa , Samalan Amrutha , Tytgat Michael , Karnam Raveendrababu , Youssef Ayman
Published: September 2022

Muography (or muon radiography) is an imaging technique that relies on the use of cosmogenic muons as a free and safe radiation source. It can be applied in various fields such as archaeology, civil engineering, geology, nuclear reactor monitoring, nuclear waste characterization, underground surveys, etc. In such applications, sometimes deploying muon detectors is challenging due to logistics, e.g. in a narrow underground tunnel or mine. Therefore, we are developing muon detectors whose design goals include portability, robustness, autonomy, versatility, and safety. Our portable muon detectors (or “muoscopes”) are based on Resistive Plate Chambers (RPC), planar detectors that use ionization in a thin gas gap to detect cosmic muons. Prototype RPCs of active area 16×16 cm2 and 28 × 28 cm2 were built in our laboratories at Louvain-la-Neuve (UCLouvain) and Ghent (UGent) to test and compare various design options. Benefiting from the experience gained in building and operating these prototypes, we are proceeding towards the development of improved prototypes with more advanced technical layout and readiness. In this paper we provide the status of our performance studies, including the cross-validation of the two types of prototypes in a joint data taking, and an outline of the direction ahead.
Design method of interconnection struts between flaps of large transport aircraft
Authors: ZHOU Xiaochen , LUO Yubo , XUE Pu , LU Jianguo
Published: September 2022

In the design of the modern large transport aircraft, flap system has become a standard configuration, which can increase the maximum wing lift and the climb rate of the aircraft. Meanwhile, the reliability of the flap system has always been the focus point of the aviation industry. The interconnection strut between flaps is a kind of redundancy design, which mitigates the failure of flap system enhancing flap system reliability. Since 1980s, aircraft manufacturers such as Airbus and Boeing have designed many kinds of ICS for the large transport aircraft like A320, B737. Meanwhile, there is some study on ICS in China, which is still in its infancy. In this paper, the design method of ICS is studied, and the important design parameters of ICS are proposed. A new kind of ICS is designed, and the validity and rationality of ICS design are verified. Firstly, the multi-body dynamic model for the flap system is established and the working principle and important design parameters of ICS between flaps are studied; and then the energy absorbing characteristics of ICS energy absorbing elements are studied; finally, a new ICS is designed, and its mechanical properties and mitigation effect on flap system failure are simulated to verify the effectiveness and rationality of the design.
The white noise standard sample method and application for subjective noise evaluation
Authors: DENG Yunyun , CHEN Ke'an , LI Hao , DANG Bo , LIU Jianben
Published: September 2022

The anchored scoring method is one of the widely used subjective sound evaluation methods. The comparability between subjective sound evaluation data obtained from different sample sets can be enhanced by selecting the standard sound sample as reference sample in subjective sound evaluation, thus facilitating the horizontal comparison between different evaluation results. However, the applicability of the standard sound sample method is poor in the experiments on evaluating some types of noise because the mechanisms of annoyance caused by different types of noise are discrepant. Therefore, the standard sound sample method for white noise that takes the existing pure tone as standard sample is proposed. Taking the evaluation results of the common anchored scoring method as benchmark, the experimental study of the performances of the standard sound sample method and the anchored scoring method was carried out according to the evaluation of the annoyance degrees of the two types of similar noise combination or dissimilar noise combination that have obviously different spectra and perceptual characteristics. The results show that the standard sound sample method for pure tone is suitable for noise with obvious tonal perception and that the standard sound sample method for white noise is suitable for broadband noise with weak tonal perception. Finally, the method of conversion between the annoyance evaluation results on different reference samples is studied to enhance the applicability of the standard sound sample method.
Simulated annealing whale radar resource scheduling algorithm based on Cauchy mutation
Authors: HU Bin , ZHU Yahui , ZHOU Yannian
Published: September 2022

In order to improve the effectiveness of radar resource scheduling, a Cauchy mutation simulated annealing whale radar resource scheduling algorithm is proposed in this study. The algorithm integrates the time resources, computing resources and the number of tasks completed of the radar. The algorithm is based on the degree of attribute matching between phased array radar data channels and tasks, so as to establish the task assignment model of the phased array radar for multiple targets. The idea of Cauchy mutation and simulated annealing is integrated into the whale optimization algorithm, which improves the optimization effect of the algorithm. Compared with the more popular camel optimization algorithm and balance optimization algorithm, the algorithm proposed in this paper has better performance in tracking task scheduling rate, average time shifting rate and scheduling value. The algorithm also shows excellent ability to solve the radar task scheduling issues.
Multi-objective optimization of power distribution of hybrid power source based on differential evolution algorithm
Authors: ZHANG Guofei , LI Zhicheng , REN Guizhou , LI Yuyao , QI Yizhong , SI Yuanquan
Published: September 2022

The hybrid power source needs to achieve the excellent power distribution control to enhance the vehicle performance, the optimization algorithm can automatically seek the optimal target according to vehicle requirements to achieve the best power distribution of hybrid power source. Power consumption is one of the core indicators for evaluating power distribution control of hybrid power source, as well as the current fluctuation of battery is an important factor that affects its power consumption and cycle life. Taking the fully-active hybrid power source configuration as the application object, a differential evolution algorithm with fast convergence speed and strong global search ability to achieve real-time power distribution control with multiple optimization goals is introduced by fully considering two important parameters of power consumption and battery current fluctuation, the power consumption model for the hybrid power source is established, the functional relationship between the power consumption of hybrid power source, current change of battery and its output current is given. In this algorithm, the minimum power consumption of the hybrid power source and the minimum change rate of the battery output current are selected as the optimization goals, the weight coefficients of the two optimization goals are assigned to seek the influence relationship between the two optimization goals. The empirical results from a simulation verify effectiveness and reliability of the designed scheme. The research results provide a reference for controlling the power distribution and optimizing the hybrid power source of electric vehicle.
Moisture Sorption Behaviour of Concrete Mixtures Containing Chlorides and the Resulting Electrolytic Resistivity in Relation to the Estimated Corrosion Risk
Authors: Fraundorfer Andreas , Heilmayer Thomas , Dauberschmidt Christoph , Gehlen Christoph
Published: September 2022

When using corrosion monitoring on reinforced concrete structures exposed to chloride, self-corrosion can play a decisive role in the interpretation and evaluation of the results. Only a part of the corrosion current can be measured electrochemically as element current. A significant proportion of the cathode process takes place on the measuring anode electrode itself. With decreasing water content of the concrete, the ratio of self-corrosion current to measurable element current increases. Corrosion tests on this topic are currently being carried out at the Munich University of Applied Sciences in cooperation with the Technical University of Munich. The moisture sorption isotherms determined at the beginning of the corrosion tests for the concrete mixtures investigated are presented here. Additionally, the electrolytic resistivities of the concrete mixtures in dependence on their water and chloride contents have been evaluated. In consideration of literature results, a moisture range can be evaluated that is associated with harmless corrosion processes.
Forensic Investigation Concerning Inspection and Diagnosis of Condition of Water Storage Systems in the Gulf
Authors: Grantham Michael , Polder Rob
Published: September 2022

Sandberg were asked to visit and comment on a sizeable project in the Gulf involving water storage towers, ground reservoirs and ancillary buildings in contemplation of legal proceedings. The structures had been built by a contractor but some problems had occurred in construction due to the high temperatures and issues with the concrete placement. The main issue that needed to be resolved was whether the problems that occurred were within acceptable limits for that type of construction and what repair recommendations were appropriate.

The Client for the project had rejected the structures and was aiming for demolition and reconstruction which was a draconian step, given the level of problems – all of which were easily repairable. A significant amount of misdiagnosis had occurred with dark flecks on the surface of reservoirs being attributed to corrosion of reinforcement, for example, when in fact they were due to mould growth on the surface of the concrete and were literally surface deep only. There were also significant questions to be answered as to what constituted an acceptable level of leakage from water storage towers. An issue was also present with very severe corrosion to some reinforcing bars close to ground level in several ground reservoirs, despite the reinforcement being epoxy coated. It was considered highly likely that this damage was in fact due to stray current corrosion from current leakage from the cathodically protected water pipelines that delivered water to the facilities in question.This paper will discuss the inspection and diagnosis of the problems and the feasibility and need for appropriate repairs.
Preliminary evaluation of Pier cap from an ASR affected bridge in Central Canada
Authors: Kristufek Leah , Zahedi Andisheh , Tawil Dana , Sanchez Leandro , Martin-Perez Beatriz , Noël Martin
Published: September 2022

The Bridge, a highway bridge structure, was built using a suspected alkali-silica reactive aggregate in the 1960’s in a city in central Canada. Its concrete elements experienced rapid deterioration resulting in the need for costly increased repairs and rehabilitations. Alkali-silica reaction (ASR) is one of several damage mechanisms which might be contributing to damage of concrete elements. Infrastructure in central Canada experiences frequent freeze-thaw cycles, and heavy use of de-icing salts in winter as well as high heat and humidity in summer which might intensify distress. In recent years several concrete elements were selected for further assessment. Among them, five segments of a decommissioned Pier cap were selected for preliminary evaluation through visual inspection (conventional, semi-quantitative and quantitative using the cracking index) and non-destructive techniques (Schmidt hammer, ultrasonic pulse velocity and surface resistivity). Preliminary assessment results will be used to determine the appropriate locations (i.e., demonstrating the lowest/ highest deterioration) to extract cores for further assessment. Future work will be conducted on extracted cores using a multi-level assessment technique consisting of mechanical (compressive testing and stiffness-damage test) and microscopic procedures (the damage rating index and SEM) to assess the condition of the Pier cap.
Approach to the development of a model to quantify the quality of tendon localization in concrete using ultrasound
Authors: Küttenbaum Stefan , Maack Stefan , Taffe Alexander
Published: September 2022

Each engineering decision is based on a number of more or less accurate information. In assessment of existing structures, additional relevant information collected with on-site inspections facilitate better decisions. However, observed data basically represents the physical characteristic of interest with an uncertainty. This uncertainty is a measure of the inspection quality and can be quantified by expressing the measurement uncertainty. The internationally accepted rules for calculating measurement uncertainty are well established and can be applied straightforwardly in many practical cases. Nevertheless, the calculations require the occasionally time-consuming development of an individually suitable measurement model. This contribution attempts to emphasize proposals for modelling the non-destructive depth measurement of tendons in concrete using the ultrasonic echo technique. The proposed model can serve as guideline for the determination of the quality of the measured information in future comparable inspection scenarios.
Determination of surface properties of treated cement pastes by acoustic methods and scratch test - pilot experiments
Authors: Topolář Libor , Kalina Lukáš , Kocáb Dalibor , Iliushchenko Valeriia , Bílý Petr , Fládr Josef
Published: September 2022

The concrete has been and at the same time will be the most used construction material worldwide. It is exposed to various physical and chemical degradation processes that deteriorate its properties and shorten its service life in most applications. As most of the detrimental effects on concrete come from the ambient environment, the quality of concrete surface plays a key role in the overall concrete performance. It should be resistant to abrasion, free of microcracks and open pores to prevent ingress of water, aggressive solutions, and gases. To enhance the properties of the concrete surface, various approaches can be used. The treatment via silicate-based sealers is becoming increasingly popular in concrete technology, especially in preventing deterioration when exposed to highly aggressive environments. This contribution focuses on applying unconventional test methods (e.g. combined scratch/acoustic emission method) to detect the fundamental properties of the treated cementitious surfaces will also provide a new perspective approach of material testing, which may be in the future advantageously used in technical practice. The present combined scratch/acoustic emission test evaluation will provide an excellent insight into lithium silicate sealers’ physical behaviour on fine-grained cement-based materials during this test.
Sewer concrete subjected to biogenic acid corrosion: analysis of concrete deterioration phases using QEMSCAN
Authors: Bakera Alice T , Alexander Mark G
Published: September 2022

QEMSCAN (Quantitative Evaluation of Minerals by Scanning Electron Microscopy) was used to analyse the evolution of cementitious phases of sewer concrete after biogenic acid attack. Two concrete mixes; a blend of Sulphate Resisting Portland Cement and Fly Ash (SRPC+FA) and Calcium Sulpho-Aluminate (CSA) cement, with calcite and siliceous aggregates, were subjected to a field sewer environment, with a maximum H2S gas concentration of 100 ppm, for about two years. After exposure, both concretes experienced thickness losses, with CSA indicating mass gain and SRPC+FA mass loss. QEMSCAN analysis results indicated that SRPC+FA was rich in calcium silicate hydrates in the intact zone, Mg-silicate in the transition zone, and Al-silicate, gypsum, and quartz in the deterioration layer. CSA contained ettringite and portlandite in the intact zone, gypsum and aluminate phases in the deterioration zone, while the transition zone was challenging to observe due to the superimposition of ettringite before and after the attack. It was concluded that, despite CSA showing a lower corrosion rate than SRPC+FA, it exhibited severe deterioration under QEMSCAN. Therefore, QEMSCAN is a potential tool for preliminary analysing of concrete microstructural phases under biogenic acid attack. However, it should be incorporated with other microstructural analysis tools.
Rehabilitation and Repair of Concrete Overlays
Authors: King Dan , Taylor Peter
Published: September 2022

Concrete overlays are a growing solution in the United States for pavement rehabilitation and preservation. Many different overlay types and designs can be used based on existing conditions and to achieve a variety of design goals. Recent performance studies have indicated that concrete overlays are capable of providing an extended service life of 35 years or more. However, the intended design life of an overlay may be shorter, and in some cases, overlays experience early distresses and failures. Because many agencies are new to concrete overlays, there is a growing need to identify best practices for rehabilitation and repair of these pavements. This paper presents a survey of typical shortand long-term distresses that have been observed on US concrete overlay projects. Common failure modes vary based on overlay type and design details, and distresses frequently depend on local materials and climate conditions. Best practices and case studies for rehabilitation and repair of concrete overlays are identified, offering options both for extension of concrete overlay service life as well as rehabilitation or reconstruction with a new pavement surface.
Experimental testing on the structural capacity of coupling beams with non-anchored longitudinal rebars
Authors: Daniel Torrealva , Joel Arzapalo
Published: September 2022

Coupling beams are structural elements which connect shear walls to improve the lateral stiffness and allow to transfer shear forces, while possessing sufficient ductility to dissipate the energy produced due to the lateral displacement. An error in the construction of a 16-story buildings resulted in that only the bottom layer of the longitudinal reinforcement bars in all coupled beams are anchored into the lateral walls, the upper longitudinal bars are cut before anchored to the lateral walls. The reconstruction of all coupled beams in the building is technical and economically non-feasible therefore, to propose a more efficient and less costly retrofit procedure, an experimental study is undertaken to analyze the real structural capacity of these coupling beams. Carbon fiber reinforced polymer (CFRP) is chosen as the reinforcement material for the upper part of the beams. A total of three specimens are tested, two of them under cyclic quasi-static load to determine the flexural capacity of the cross section in the interface wall-coupling beam, and one of them under monotonic loading to determine the shear capacity of the cracked cross section. The results of the cyclic test showed a very limited contribution of the CFRP in the flexural capacity when the fiber is in tension. However, the flexural behavior of the section with the lower reinforcement in tension is not affected by the upper non-anchored bars and showed a flexural capacity and energy dissipation according to the existing rate of the steel reinforcement. The experimental results are used to develop a finite element model which reproduce the structural behavior of the beams with the construction error.
Actual achievements and future challenges of HPFRC for structural rehabilitation of bridges
Authors: Reggia Adriano , Trabucchi Ivan , Morbi Alessandro , Plizzari Giovanni A.
Published: September 2022

The state of road infrastructures in many advanced countries is rapidly changing under the impulse of massive funding from governments, eager to have more efficient and safer transportation systems. The use of well-known materials such as fibre-reinforced concrete (FRC) is finding a growing space for structural rehabilitation of bridges; the adopted material is often defined as High performance fibre reinforced concrete (HPFRC) due to its enhanced performance. The paper presents the principal findings of an EU-funded project that involved the repair of two road bridges in Italy using HPFRC. The project has successfully carried out the jacketing of bridge piers and cap-beams, heavily damaged by corrosion, with a new HPFRC layer of reduced thickness (40-60 mm) and limited use of steel reinforcements. Experimental tests carried out in the laboratory of the University of Brescia on 1:2 scaled specimens have shown the possibility to increase the load bearing capacity of the cap beams (with respect to vertical loading) up to 73%, with moderate effects on the change in stiffness and ductility of the existing structure. Based on field and laboratory experience, the article eventually presents some new challenges for the use of HPFRC in the reduction of environmental impact of construction industry.
Ion distribution in concrete overlay, mapped by laser induced breakdown spectroscopy (LIBS), modified by an embedded zinc anode
Authors: Schwarz W. , Wilsch Gerd , Katsumi N. , Ebell G. , Völker T.
Published: September 2022

Galvanic corrosion protection by embedded zinc anodes is an accepted technique for the corrosion protection of reinforcing steel in concrete. Galvanic currents flow between the zinc anode and the steel reinforcement due to the potential difference that is in the range of a few hundred mV. The ion distribution was studied on two steel reinforced concrete specimens admixed with 3 wt.% chloride/wt. cement and galvanically protected by a surface applied EZ-anode. On both specimens, a zinc anode was embedded and glued to the concrete surface by a geo-polymer-based chloride-free binder. At one specimen, the EZ-anode was operated for 2,5 years, the EZ-anode at the other specimen was not electrically connected to the reinforcement, this specimen serves as a reference. Both specimens have been stored under identical conditions. The ion distribution between the anode (EZ-ANODE) and cathode (steel reinforcement) was studied by laser-induced breakdown spectroscopy (LIBS) after 7 months, 12 months, and 2,5 years. Results of the LIBS studies on the specimen with activated EZ-anode after 7 months, 12 months, and 2,5 years and of the reference specimen after 2,5 years are reported. Results show that diffusion of ions contributes to the changes in the ion distribution but migration, especially of chlorides towards the EZ-anode is significant despite the weak electric field – several hundred millivolts generated by the galvanic current. Results show that chloride ions accumulate near the zinc-anode as in water-insoluble zinc-hydroxy chlorides Simonkolleit.
The environmental impact of service life-extending repair for corrosion damaged reinforced concrete balconies: a case study in a coastal context
Authors: Renne Neel , Craeye Bart , Buyle Matthias , Audenaert Amaryllis
Published: September 2022

Nowadays a vast number of concrete structures are approaching the end of their expected service life. The need for sustainable rehabilitation (maintenance and repair) is urgent and due to the expected deterioration of buildings and civil structures, there will be a great need for preventive and/or curative interventions in the near future. More than 2/3 of the damage to reinforced concrete structures is linked to reinforcement corrosion, which can affect the durability of the structure and the residual load-bearing capacity. With the necessary transition towards a circular economy and the Sustainable Development Goals in mind, it is important to deviate from considering only the technical requirements and initial costs during the design of concrete structures. Hence, the environmental impact over the entire life cycle and the intended service life extension need to be considered as well. A typical residential building in a Belgian coastal environment with damaged reinforced concrete balconies is selected as case study to evaluate different frequently used repair techniques (i.e. patch repair, conventional repair, galvanic cathodic protection, impressed current cathodic protection and total replacement) by means of a life cycle assessment. Several sensitivities are mapped by analysing the influence of the intended service life extension, the volume and configuration of the construction, the repair mortar composition and the application of coating/waterproofing. It was stressed that these uncertainties could have a substantial effect on the environmental impact and highlight the domains where further research is needed (e.g. assumed life span and composition of repairs). Due to this manner, it is not possible to identify one environmental optimal repair method. However, for a short service life extension (e.g. 5y) small interventions like patch repair seem to be more sustainable while methods like cathodic protection and conventional repair are preferable for longer service life extensions (e.g. 40y).
The investigations on properties of self-healing concrete with crystalline admixture and recycled concrete waste
Authors: Manhanga Fallon Clare , Rudžionis Žymantas , Ivanauskas Ernestas , Augonis Algirdas
Published: September 2022

The concept of self-healing concrete is becoming more necessary as sustainability in construction is more desirable. Amongst the current solutions in this technology are autogenous, chemical, and bacterial self-healing. It is paramount that secondary raw materials be used in the production of selfhealing concrete as a form of a sustainable solution. Therefore, in this paper, the admixture “Betocrete-CP-360-WP”, which is a crystallizing waterproofing admixture with hydrophobic effect and is 100% recyclable, has been used and its effect on the physical, chemical, and mechanical properties of concrete, as well as selfhealing capabilities of concrete, have been determined. According to the obtained results, the crystalline additive “Betocrete-CP-360-WP” has no effect on density and slightly increases the amount of entrained air in the concrete mix. However, it does decrease the workability of the concrete mixture which could prove problematic in transportation to the construction site or in concreting in general. Also, with the crystalline admixture in the concrete mix, a 60% reduction in concrete compressive strength after one day of hardening has been estimated, but after 7 and 28 days, the strength attained is within the ranges of the control samples. In addition, concrete containing Betocrete-CP360-WP was 30% less water permeable as compared to control samples. The self-healing efficiency of the concrete was determined by a water flow test through a formed crack (approximately 0.35 mm wide). This was done by gluing a plastic pipe to the top of the cracked concrete specimens and maintaining a constant pressure of the water in the pipe. The experiment was continued for 28 days, and the crack self-healing efficiency of the concrete was calculated from the differences in the amount of water passed through the crack before healing and after 7, 14, 21 and 28 days of the healing process. After 28 days of the water flow test, the cracks in the concrete with the crystalline admixture and recycled concrete dust were completely healed, while the control specimens were not.
Using simple soil water content sensors to measure water availability in fresh concrete
Authors: Smit Martha S. , Boshoff William P. , Warren Luke G.
Published: September 2022

Preventing plastic shrinkage cracks improves the durability of concrete. This is because plastic shrinkage cracks serve as pathways by which corroding agents can penetrate concrete. Freshly cast concrete is a saturated mixture of reactive and non-reactive materials. As water moves out of the concrete mass and as water is used in the hydration process, the free water in the mixture reduces. Eventually, the mixture can be considered to be unsaturated. In this research project, the viability of using soil water content sensors to measure the change in water availability in concrete from fresh state to early-age was explored. The soil water content sensors measured dielectric permittivity. The dielectric permittivity, cumulative evaporation and setting time of mortars with varying water/cement ratios were tested. It was found that the dielectric constant was influenced by changes in fresh mortar and that the sensors have the potential to qualitatively monitor cement content, bleeding, hydration and evaporation. Further work is required in this field.
Early Age Properties of High-Performance Concrete
Authors: Mostert Derek , Kearsley Elsabe
Published: September 2022

High Performance Concrete is used to not only minimize the environmental footprint of the cement and concrete industry, but also to enable the design and rapid construction of taller and more slender structures. Despite the significant change in concrete property requirements, the properties of concrete as used during design of concrete structures are mostly still based on 28-day water cured compressive strength, stiffness, long term drying shrinkage and creep. The relevance of these measured properties on the actual behaviour of the structure should be questioned as high strength concrete is known to have low water/cement ratios resulting in significant early age shrinkage, which is currently not taken into account by designers. This paper is based on a study where the early age properties of concrete was investigated, with specific focus on the first 24 hours after casting. The effect of factors such as low water/cement ratio, admixtures, ambient and material temperatures, shutter type and cast volume on properties such as setting time, early age shrinkage, strength development and stiffness was studied and observed trends discussed in this paper.
Vaskuläre Zufallsbefunde in der MRT des Schädels
Authors: Berkefeld Joachim
Published: September 2022

In etwa 9 von 1000 kranialen MRT-Untersuchungen werden pathologische Veränderungen der zerebralen Gefäße entdeckt. Radiologen sind häufig diejenigen, die ihren Patienten solche
Zufallsbefunde mitteilen. Die Betroffenen sind oft verunsichert und wollen wissen, was dieser Befund für sie bedeutet. Es ist daher das Ziel dieses Beitrags, Grundlagen für eine adäquate
Beratung über die Risiken und das weitere Vorgehen zu vermitteln.
Alkenylboronic Ester Activation to Nucleophilic Addition and Electrophilic Trapping with Carbonyl Groups
Authors: Fernández Elena , González Sara
Published: September 2022

Carbolithiation of (1-phenylvinyl)boronic acid pinacol ester with tert-butyllithium was used to generate α-phenylboryl carbanions that reacted in a straightforward manner with carbonyl groups through a boron–Wittig sequence. When unhindered α,β-unsaturated carbonyl compounds were used, 1,4-addition of the α-phenylboryl carbanions was observed over the boron–Wittig sequence.
A Brønsted Acid Catalyzed Easy Access to Conjugated Diene-­Diones from Tertiary Propargyl Alcohols and 1,3-Dicarbonyl ­Compounds
Authors: Chatterjee Paresh Nath , Kalita Gitumoni , Khatua Snehadrinarayan
Published: September 2022

A simple protocol catalyzed by a Brønsted acid, trifluoromethanesulfonic acid (CF3SO3H), to synthesize conjugated diene-diones from easily accessible tertiary propargyl alcohols and 1,3-dicarbonyl compounds is described. Reactions are performed in an air atmosphere by using undried solvents with water being the environmentally benign side product of the process. Preliminary synthetic applications of the conjugated diene-diones in the formation of conjugated dieneones and furans are also reported herein.