bluuebunny/crossref_metadata_2025 huggingface dataset:
Iterative heterogeneous graph learning for knowledge graph-based recommendation
Authors: Liu Tieyuan , Shen Hongjie , Chang Liang , Li Long , Li Jingjing
Published: April 2023

Incorporating knowledge graphs into recommendation systems has attracted wide attention in various fields recently. A Knowledge graph contains abundant information with multi-type relations among multi-type nodes. The heterogeneous structure reveals not only the connectivity but also the complementarity between the nodes within a KG, which helps to capture the signal of potential interest of the user. However, existing research works have limited abilities in dealing with the heterogeneous nature of knowledge graphs, resulting in suboptimal recommendation results. In this paper, we propose a new recommendation method based on iterative heterogeneous graph learning on knowledge graphs (HGKR). By treating a knowledge graph as a heterogeneous graph, HGKR achieves more fine-grained modeling of knowledge graphs for recommendation. Specifically, we incorporate the graph neural networks into the message passing and aggregating of entities within a knowledge graph both at the graph and the semantic level. Furthermore, we designed a knowledge–perceiving item filter based on an attention mechanism to capture the user’s potential interest in their historical preferences for the enhancement of recommendation. Extensive experiments conducted on two datasets in the context of two recommendations reveal the excellence of our proposed method, which outperforms other benchmark models.
Dietary factors potentially impacting thiaminase I-mediated thiamine deficiency
Authors: Edwards Katie A. , Randall Eileen A. , Wolfe Patricia C. , Angert Esther R. , Kraft Clifford E.
Published: April 2023

Fish population declines from thiamine (vitamin B1) deficiency have been widespread in ecologically and economically valuable organisms, ranging from the Great Lakes to the Baltic Sea and, most recently, the California coast. Thiamine deficiencies in predatory fishes are often attributed to a diet of prey fishes with high levels of thiamine-degrading (e.g., thiaminase) enzymes, such as alewives, rainbow smelt, and anchovies. Since their discovery, thiaminase I enzymes have been recognized for breaking down thiamine into its pyrimidine and thiazole moieties using various nucleophilic co-substrates to afford cleavage, but these studies have not thoroughly considered other factors that could modify enzyme activity. We found the thiaminase I enzyme from Clostridium botulinum efficiently degrades thiamine in the presence of pyridoxine (vitamin B6) as a co-substrate but has relatively limited activity in the presence of nicotinic acid (vitamin B3). Using fluorescence measurements, thiamine degradation in an over-the-counter complete multivitamin formulation was inhibited, and a B-complex formulation required co-substrate supplementation for maximal thiamine depletion. These studies prompted the evaluation of specific constituents contributing to thiaminase I inhibition by both chromatography and fluorescence assays: Cu2+ potently and irreversibly inhibited thiamine degradation; ascorbic acid was a strong but reversible inhibitor; Fe2+, Mn2+ and Fe3+ modulated thiamine degradation to a lesser degree. The enhancement by pyridoxine and inhibition by Cu2+ extended to thiaminase-mediated degradation from Burkholderia thailandensis, Paenibacillus thiaminolyticus, and Paenibacillus apiarius in tryptic soy broth supernatants. These co-substrate limitations and the common presence of inhibitory dietary factors complement recent studies reporting that the intended function of thiaminase enzymes is to recycle thiamine breakdown products for thiamine synthesis, not thiamine degradation.
Surgical management and clinical outcome of cervical, thoracic and thoracolumbar spinal tuberculosis in a middle-European adult population
Authors: Kilinc Fatma , Setzer Matthias , Behmanesh Bedjan , Jussen Daniel , Geßler Florian , Prinz Vincent , Czabanka Marcus
Published: April 2023

Spinal tuberculosis is due to globalization no longer a disease limited to developing nations. It remains in Germany a rarity and still a difficult diagnosis. Here we analyzed patients with spinal tuberculosis treated at our neurosurgical department. According to the infected anatomic segment, patients were assigned in one of three groups. Surgery was performed when neurological deficit due to mechanical compression, deformity, instability, severe pain, necrotic bone or failure to respond to anti-tuberculous treatment were observed. We identified 34 patients with spinal tuberculosis who underwent surgical treatment. In the cervical spinal tuberculosis group, there were 15 cases (46.9%) In most cases treatment consisted of spinal instrumentation. In the thoracic group, 10 cases (29.4%) were observed. The treatment was performed by dorsolateral spinal instrumentation. For the thoracolumbar group, 9 cases (26.4%) were observed. In most cases dorsolateral spinal instrumentation was performed. One patient in the first group and one patient in the third group relapsed after operation. A second surgery was necessary. Patients with chronic back pain, immigration background and/or neurological deficit spinal TB should be considered as a differential diagnosis. Combined surgical intervention and medical treatment is associated with a favorable outcome.
Atomic layer deposition of Er-doped yttrium aluminum gallium garnet nanofilms with tunable crystallization and electroluminescence properties
Authors: Yu Zhimin , Yuan Kang , Yang Yang , Sun Jiaming
Published: April 2023

Precise adjustment of Ga/Al ratios in Er-doped Y3(AlxGa1−x)5O12 nanolaminates realizes the regulation of crystallization temperature, correlated morphology and electroluminescence performance.
Factors Related to College Major Selection in Communication Sciences and Disorders: Application of the Theory of Planned Behavior
Authors: Choo Ai Leen , Gurevich Naomi , Dadzie Nana , Reidenbach Kayla , Laxman Malini , Ngo Kelley
Published: April 2023

Purpose:

The growing number of racial and ethnic minorities in the United States is not reflected in the speech-language pathology profession, with ramifications for the diverse communities it serves. Despite decades of initiatives, the numbers of racial and ethnic minorities entering the profession have been modest. The aim of this pilot study is to explore potential factors that influence decision making for a college major that could inform strategies for underrepresented racial and ethnic minority (URM) recruitment into communication sciences and disorders (CSD) programs.

Method:

The theory of planned behavior was used as a framework to explore the influences on students' selection of college majors with a particular focus on speech-language pathology. Students enrolled and not enrolled in CSD programs were surveyed about their attitudes, perceived behavioral control, and subjective normative pressure (e.g., perceptions of race and ethnic representation, familiarity with speech-language pathology, and family education).

Results:

There were significant differences between CSD and non-CSD respondents, and between URM and White respondents in their perception of representation and exposure to the profession. The majority of URM students reported that race and ethnic representation is important in their chosen job. URM students were less likely than White students to know anyone who has received speech-language therapy or who is a speech-language pathologist.

Conclusion:

Findings suggest that initiatives to increase representation and diverse role models, and early exposure to the profession for URM students should be areas of focus in the efforts to diversify the profession.
A Brief History of the Study of High Energy Cosmic Rays using Arrays of Surface Detectors
Authors: Watson A. A.
Published: April 2023

A brief history of the development of surface detectors for the study of the high-energy cosmic rays is presented. The paper is based on an invited talk given at UHECR2022 held in L’Aquila, 3 – 7 October 2022. In a complementary talk, P Sokolsky discussed the development of the fluorescence technique for air-shower detection.
The energy spectrum of ultra-high energy cosmic rays measured at the Pierre Auger Observatory and the Telescope Array
Authors: Bergman D. R. , Deligny O. , Fenu F. , Fujii T. , Fujita K. , Kim J. H. , Lhenry-Yvon I. , Maris¸ I. , Luce Q. , Roth M. , Salamida F. , Tsunesada Y. , Verzi V. ,   for the Pierre Auger,   the Telescope Array
Published: April 2023

In the study of cosmic rays, the measurement of the energy spectrum of the primaries is one of the main issues and provides fundamental information on the most energetic phenomena in the Universe. At ultrahigh energies, beyond 1018 eV, the cosmic rays are studied by the two largest observatories built so far, the Pierre Auger Observatory and the Telescope Array. Both observatories are based on a hybrid design and reported a measurement of the energy spectrum using the high duty cycle of the surface detector and the calorimetric estimation of the energy scale provided by the fluorescence detector.

The differences among the reported spectra are scrutinized by a working group made by members of the Pierre Auger and Telescope Array Collaborations. The two measurements have been found well in agreement below 1019 eV while, at higher energies, they show an energy-dependent difference that is beyond the systematic uncertainties associated to the energy scale.

In this contribution we review the status and perspectives of the working group activities including new studies aiming at addressing the impact on the flux measurement at the highest energies of potential biases in the estimation of the shower size.
A Bayesian source association analysis of UHECRs: Impact of the Galactic magnetic field and composition
Authors: Watanabe Keito , Fedynitch Anatoli , Capel Francesca , Sagawa Hiroyuki
Published: April 2023

We present a statistical analysis of the association between UHECRs and proposed astrophysical sources. Our approach is based on the Bayesian hierarchical framework presented in Capel & Mortlock 2019, but with notable extensions. Using CRPropa3, we now include the lensing effect of the Galactic magnetic field and explore the impact of heavier compositions. This analysis directly connects to the physics of UHECR propagation so that each detected event is allowed different possible deflections and energy-loss horizons based on its measured energy, arrival direction and the corresponding uncertainties. In this way, we can easily interpret the connection to proposed sources in a physical way. We verify our approach using simulated data and then present our results with views of the Northern and Southern skies thanks to publicly available data from both the Telescope Array experiment and Pierre Auger Observatory.
Cosmic ray acceleration by multiple shocks in the jets of Active Galactic Nuclei
Authors: Müller Ana Laura , Araudo Anabella
Published: April 2023

Active galactic nuclei are one of the most promising sources for accelerating particles up to the highest energies. In this contribution, we present a scenario in which cosmic rays are accelerated in multiple shocks created by the interaction of relativistic AGN jets with the winds of embedded massive stars. We solve the Fokker-Planck equation considering escape and radiative losses as well as the collective effect of the shocks and the reacceleration of the particles. Finally, we calculate the maximum energies that the particles can achieve and discuss the possibility of producing ultra-high energy cosmic rays in this astrophysical situation.
Production of high-energy neutrinos in binary-neutron-star merger events
Authors: Rossoni Simone , Boncioli Denise , Sigl Günter
Published: April 2023

High-energy neutral astrophysical messengers, such as neutrinos and photons, can be produced by the interaction of ultra-high-energy cosmic rays (UHECRs) with radiation fields, either during extragalactic propagation or within source environments. Neutrinos and gamma-rays can play a crucial role in the study of acceleration mechanisms of cosmic rays. In particular, after being produced, neutrinos leave the source environment and propagate to the Earth without further interactions. They are only subject to energy redshift and flavour oscillation, which makes them bearers of otherwise inaccessible information about their sources. We study high-energy environments of the type that are likely to be the end states of a binary-neutron-star (BNS) merger, and we model their local photon field as a black body at a given temperature. Using a modified version of the Monte Carlo code SimProp v2r4 we simulate the propagation and interaction of UHECRs through these environments. We consider several combinations for the spectral index and high-energy cutoff of the UHECR protons, in order to obtain the escaped neutrino flux. We propagate these fluxes to the Earth and compare to the astrophysical IceCube neutrino flux to obtain constraints on the BNS merger spectra properties, emissivity and density rate.
Probing Lorentz violation at ultra-high energies using air showers
Authors: Niechciol Marcus , Duenkel Fabian , Risse Markus
Published: April 2023

In air showers initiated by ultra-high-energy cosmic rays in the Earth’s atmosphere, even the secondary particles created in the start-up phase are produced at energies far above those accessible by other means. These high-energy particles can be used to search for New Physics, such as a violation of Lorentz invariance. We focus on isotropic, nonbirefringent Lorentz violation in the photon sector and consider the two cases κ < 0 and κ > 0 (i.e., the velocity of photons is larger/smaller than the maximum attainable velocity of standard Dirac fermions). In both cases, processes that are forbidden in the standard, Lorentz-invariant theory (κ = 0) become allowed, in particular photon decay in the case κ < 0 and vacuum-Cherenkov radiation for κ > 0. Implementing these processes into air-shower simulations, we found that the development of an air shower at the highest energies can be significantly impacted, specifically the average atmospheric depth of the shower maximum X max and its shower-to-shower fluctuations σ(X max). Comparing these simulations to actual measurements, we were able to obtain much stricter bounds on this specific type of LV in the case κ < 0 than possible with previous methods. We discuss these limits and, in addition, present first results for the case κ > 0.
On the mystery of the multi-muon flux at the TeV cosmic-ray energy range
Authors: Tuneu Jordi , Filip Peter , Santos Eva
Published: April 2023

Current Monte Carlo simulations do not provide a good description of the muon component of extensive air showers. Many air shower experiments report discrepancies between their data and Monte Carlo predictions, ranging from the TeV scale up to the highest energies. In these proceedings, we address the seasonal variation of the multi-muon events observed by the NOvA Near Detector (ND). For our studies, we use the general-purpose Monte Carlo code FLUKA to treat the transport and interaction of the air-shower particles in the atmosphere and other media. Our design considers a multilayered atmosphere and a layered underground approximated to match the NOvA ND location and detector geometry. Our atmospheric model uses air densities for winter and summer calculated from the temperature and geopotential information for the pressure levels given by the European Center for Medium-Range Weather Forecasts (ECMWF) datasets in situ. Understanding the multi-muon flux at the cosmic ray high-energy range may lead to a better description of the muon production mechanisms in ultra-high-energy extensive air showers. In addition, it can help to improve future Monte Carlo codes or hint at new physics processes or interactions.
Absolute calibration of the JEM-EUSO photodetection modules
Authors: Trofimov Daniil , Belov Alexander , Blin-Bondil Sylvie , Creusot Alexandre , Klimov Pavel , Parizot Etienne , Prévôt Guillaume ,   Collaboration
Published: April 2023

The JEM-EUSO (Joint Experiment Missions for Extreme Universe Space Observatory) collaboration constructs a series of balloon and orbital telescopes to detect fluorescent UV emission from the Earth atmosphere, with the primary aim to study ultra-high-energy cosmic rays (UHECRs) from space.

The detectors have wide field-of-view (more than 20 degrees FOV), high temporal resolution (1-2.5 µs) and high sensitivity provided by a large aperture. Currently, one of these detectors is operating onboard the International Space Station (Mini-EUSO). The next one is planned to be launched in the spring of 2023 (EUSO-SPB2) and another one is in preparation stage (K-EUSO). These projects use the same photo-detection modules (PDMs) composed of 36 multi-anode photomultiplier tubes (MAPMTs), each with 64 pixels, for a total of 2304 pixels. Mini-EUSO uses one PDM, EUSO-SPB2 uses three and the future full-scale missions will use several tens of PDMs.

In the process of preparing and testing of PDMs, a new technique was developed to characterize their performance and provide absolute calibration of the MAPMTs used in the different JEM-EUSO missions. The method provides the efficiency of each pixel (including the sub-pixel structures), as well as the actual area occupied by the different pixels on the photocathode of the MAPMT.

The method and its application to EUSO-SPB2 PDMs at different high voltages and in different modes of operation are presented.
Self-healing biomaterials for medical applications
Authors: Leeuwenburgh Sander
Published: April 2023

Biomaterials are currently applied in increasingly complex areas such as tissue engineering, bioprinting and regenerative medicine. To this end, challenging combinations of biomaterial properties are required which usually cannot be met by conventional biomaterials. Since the early 2000s, several new concepts have been proposed to render biomaterials self-healing in order to improve the functionality of traditional biomaterials in terms of their mechanical, handling and biological properties. This presentation will provide a comprehensive overview of the field of self-healing biomaterials, ranging from self-healing of capsule-filled dental fillers and bone cements, to the self-healing behavior of modern injectable hydrogels used in regenerative medicine. More specifically, the presentation will highlight why self-healing properties of biomaterials are crucial for minimally invasive injection into the human body and achieve successful tissue regeneration.
Understanding the importance of endosporulation methods for generating endospores that can resist harsh conditions and produce calcite in bio self-healing of concrete
Authors: Rahmaninezhad Seyed Ali , Khaneghahi Mohammad Houshmand , Farnam Yaghoob (Amir) , Schauer Caroline L. , Najafi Ahmad , Street Reva M. , Sadighi Amir , Kamireddi Divya , Sales Christopher M.
Published: April 2023

Vegetative cells used for the concrete bio self-healing process often face threatening environmental conditions such as extreme temperature, pH, salinity, shear stress, and starvation during the hardening process and the service life of the concrete. These conditions can eventually lead to cell death. Since endospores are likely to remain dormant for prolonged periods and can survive, germinate, and grow under inhospitable conditions, they are a suitable bacterial phenotype to introduce into concrete for microbial-inducing calcite precipitation. This study investigated how different endosporulation methods affect the endosporulation ratio (i.e., the fraction of vegetative cells that are converted to endospores during endosporulation), as well as the germination ratio (i.e., the fraction of endospores that are converted to vegetative cells following germination) and the microbial-induced calcite precipitation (MICP) performance of germinated endospores after facing harsh conditions of concrete, specifically, freeze and that cycling. Results from this study show that thermal shock followed by cell incubation in alkaline conditions leads to increased sporulation and germination ratios. It was also observed that freeze and thaw cycling had negligible effects on calcite production by endospores, while exposure of vegetative cells to these harsh conditions led to not only less biomass and calcite production but also to a lower mass of calcite produced per mass of cells, as determined by thermogravimetric analysis (TGA). The results from this study provide key insights into improving methods for endosporulation and germination to effectively use them for bio self-healing applications in concrete.
The performance evaluation of protection barriers in bacterial self-healing mortar
Authors: Sandalci Ilgin , Guldogan Ayca Gisu , Bundur Zeynep Basaran
Published: April 2023

The early age microcracking is a significant problem in concrete structures resulting in increased permeability and decreased durability. The previous work showed thatSporasarcina pasteuriicells immobilized on natural minerals such as bentonite, diatomaceous earth, sepiolite, and pumice effectively remediated early-age microcracks in the cementitious systems by triggering microbial-induced calcite precipitation (MICP). This promising approach can solve early-age shrinkage cracking in cementitious systems. Therefore, it is essential to assess the impact of self-healing additives on drying shrinkage. This study investigates the influence of mineral-based biological additives on the drying shrinkage capacity of cement-based mortar and the possible self-healing of cracks if any occur. To achieve this goal, the free shrinkage in control (containing only minerals) and bacterial (containing bio-based additive) samples were measured based on ASTM 596-18 norms. Moreover, the performance assessment of developed self-healing additives was done by determining compressive strength and initial setting time of bacterial self-healing mortar.
Evaluation of the self-healing capacity of concrete with low-cost macro-capsules
Authors: Kannikachalam Niranjan Prabhu , Cailleux Emmanuel , De Belie Nele , Ferrara Liberato
Published: April 2023

This study focuses on the evaluation of the efficiency of a low-cost macrocapsule, using commercially available pharmaceutical capsules with specific modifications, for self-healing concrete. The macrocapsules were developed by the Belgian Building Research Institute in a previous study. The healing agent is a resin based on alkyd-urethane, a low-cost commercial product, which was selected for its compatibility with concrete and shell, and also for the following reasons: resin release, adhesion to concrete, and reduction in capillary water absorption. After their manufacturing, the macrocapsules were carefully integrated within the concrete mix at 5 volume-%, and cubes and slabs for compressive and impact tests were cast. Small beams 160 x 40 x 40 mm3 containing each three capsules (placed 15 mm above the bottom surface) were tested for flexural strength and capillary water absorption. The effect of self-healing was evaluated by sorptivity test for two different crack mouth opening displacements of 0.5 mm and 0.9 mm. In both cases, the cracks were partially or completely healed, and the mechanical properties of the macrocapsule specimens were quite the same as the reference specimens. This demonstrates that the modified low-cost macrocapsules are sufficient to heal large cracks without losing the concrete mechanical properties.
Self-healing of cement mortars based on fly ash and crystalline admixture
Authors: Stefanovska Irina , Fidanchevski Emilija
Published: April 2023

The actual study has followed the effect of fly ash and crystalline admixture on cement mortars' mechanical and self-healing properties. Three types of cementitious mortars composed of (i) 16 wt.% fly ash, (ii) crystalline admixture, and (iii) 16 wt.% fly ash and crystalline admixture were compared to the standard mortar (in compliance with EN 196-1). The capillary water absorption determined the sealing efficiency of the cracks over a period of time. The experimental results showed that by autogenous self-healing the standard mortar has a sealing efficiency of 40% after 28 days of treatment and 70% after 6 months of treatment, but the addition of fly ash and crystalline admixtures stimulated the autogenous self-healing. The best results showed the mortar (iii) containing 16 wt.% fly ash and crystalline admixture, where the sealing efficiency achieved 79% after 28 days of treatment and 98% after 6 months.
The influence of sepiolite on the self-healing capability of concrete by means of water permeability
Authors: Doostkami Hesam , Formagini Sidiclei , Roig-Flores Marta , Serna Pedro
Published: April 2023

This paper investigates the autogenous self-healing capability of conventional concrete (C30/37) mixtures with water encapsulated in sepiolite. Sepiolite was added in two conditions: previously saturated and dry, at a dosage of 5% by the cement weight. Sepiolite is added in substitution for the sand fraction. For these two mixes and a reference mix without sepiolite, disks of size f100x50 mm were produced and were pre-cracked at 28 days of age by splitting test until reaching residual cracks of 300±150 μm. Crack width was measured by using an optical microscope. Self-healing was promoted after pre-cracking in certain exposures: 1) continuous water immersion at 20°C for 56 days, 2) a high humidity environment at 20°C and 95% of relative humidity for 28 days and water immersion for additional 28 days, and 3) pre-saturation for one day and 55 days in a humidity chamber. Self-healing was analyzed with water permeability by comparing the results before and after the healing stage. Afterward, chlorides’ penetration through the healed cracks was evaluated to study the possible protection provided by crack healing. Uncracked specimens were also tested as a reference for chloride penetration. Mixes were characterized by measuring compression strength at 28 days, slump, air content, and fresh density. The results show that water immersion is an adequate way to improve autogenous self-healing. Sepiolite can improve the self-healing capability of concrete with only one day of pre-saturation and then healing in high humidity conditions, especially in mixes with sepiolite introduced in saturated conditions. On the contrary, sepiolite may have resulted in a higher chloride penetration compared to samples without sepiolite.
A comparison of potential healing agents for vascular-based self-healing concrete
Authors: Shields Yasmina , Cappellesso Vanessa , Van Mullem Tim , De Belie Nele , Van Tittelboom Kim
Published: April 2023

Vascular self-healing concrete is an innovative technology that can potentially improve the durability and longevity of concrete structures. However, limited research is available concerning this type of self-healing compared to intrinsic or capsule-based healing. As the rheology and curing properties of a healing agent can dictate the optimal design configuration of a vascular network, a series of testing procedures for evaluating healing agents is further explored. In this study, the suitability of various commercially available healing agents is considered using a vascular network system in mechanical loading and water absorption test set-ups. In this particular configuration, high sealing efficiencies were obtained for most of the healing agents used, and the polyurethanes and epoxy resin that were studied showed high load regain values. This work provides a testing methodology to select a healing agent in terms of its mechanical load regain, sealing efficiency, rheology, and curing properties, and can be used to determine a suitable healing agent for vascular healing applications.
Initial proposal of a novel voltammetric sensor system for the detection of concrete carbonation by means of PCA model
Authors: Ana Martínez Ibernón , Ramon Lliso-Ferrando Josep , Isabel Gasch , Manuel Valcuende , Manuel Gandía-Romero José , Juan Soto
Published: April 2023

The monitoring of concrete carbonation takes an important role in the structures maintenance, considering that corrosion induced by this phenomenon is one of the mainly failure causes in the Reinforcement Concrete Structures (RCS) located in industrial zones, roads and cities. Carbonation of concrete is produced by the penetration of the CO2 inside of the porous net, which is mainly combined with the Ca(OH)2 contained in the concrete pore solution producing carbonates with low solubility and eventually causing a pH drop until neutral levels. The pH drop produces the instability and final generalised destruction of the rebars passive layers, which is the step that precedes generalized corrosion. The current existing systems to detect concrete carbonation are based on potentiometric sensors to detect the pH of concrete pore solution. These have some limitations such as the interference of different reactions on the sensor surface. Considering these limitations, in this study a novel system of voltammetric Au sensors embedded in concrete for the detection of concrete carbonation was presented. In the voltammetric sensor, the potential sweep signal applied comprises the potential range where the effect of the pH variations has more influence in the sensor response. Then the response processing by means of the multivariate analysis PCA (principal component analysis) allows to manage a huge quantity of variables and to reduce the effect of the interference with other analytes, increasing the importance of the pH changes effect in the obtained data. Thus, increasing the reliability of the system to detect the concrete carbonation.
Effect of autogenous healing of narrow and wide cracks on the progression of carbonation in the walls of cracks
Authors: Pourhaji Pardis , Serna Pedro , Alonso Maria Cruz
Published: April 2023

This paper deals with the carbonation of concrete crack walls before and after healing in comparison to the carbonation of the bulk of the concrete. Natural carbonation tests were carried out on 50 MPa concrete. Disks with 50 mm thickness and 100 mm diameter were tested. A splitting test was applied to generate the crack. Different crack widths were tested, narrow crack widths below 75μm, and wide crack widths, between 75-175μm. The self-healing effect was studied after immersion for 4 months in water. Natural carbonation was carried out at 55±5 %RH 20±3°C for 6, 9 and 12 months. The carbonation front was assessed after splitting and opening the crack walls. The results show the effect of the crack width, crack length and autogenous healing that affect the progression of carbonation in the crack walls. The carbonation in the crack wall is at least twice that of the concrete. Crack widths larger than 75μm carbonate faster. Autogenous healing of the narrow cracks can reduce the carbonation front at the crack walls with compare to the unhealed narrow; however, no improvement was observed in limiting the carbonation front in the crack walls of healed wide cracks.
Environmental and Economic Sustainability Aspects in Lime-Based Construction Materials
Authors: Laveglia Agustin , Sambataro Luciano , Ukrainczyk Neven , Ortel Tina , De Belie Nele , Koenders Eddie
Published: April 2023

Lime-based construction materials (LBM) range from concrete blocks to mortars and plasters used in building new structures or to conserve our cultural heritage. However, little interest has been aroused in the scientific community about their sustainability assessment through Life Cycle Assessment. This research presents a case study carried out within the framework of the SUBLime Project (MSCA ETN-ITN network) and aims at contributing to the understanding of environmental and economic sustainability of LBM. Through a real case-study, a detailed Life Cycle Inventory was developed to calculate the environmental impact associated to different mixes, use of additives, aggregates, etc. Furthermore, Life Cycle Cost Assessment methodology was used to determine the share of different items in the total cost of the cradle-to-grave production of LBM. A thorough analysis of the combined environmental and economic results are presented along with suggestions regarding mix compositions, aggregates, additives, and critical processes in the production line to achieve more sustainable production of LB materials.
A statistical comparison between calculated and experimentally evaluated crack spacing measures given in practise codes for the design of reinforced concrete elements made with self-healing concrete
Authors: Dabral Kiran , Camacho Esteban , Ángel López Martínez Juan , Alonso Maria Cruz , Serna Pedro
Published: April 2023

Available design codes provide formulations to evaluate the maximum spacing between the cracks, which then is used to calculate the crack width in concrete structures. This paper discusses the parameters controlling the crack spacing and develops an experimental test program on a set of industrial-scale reinforced concrete elements cast with self-healing concretes to be tested under flexural actions. This study provides a wide picture of the limits of maximum, minimum, and average spacing occurring in the beams. A comparison is highlighted between the calculated and experimentally evaluated measures. It was observed that the provisions given in Eurocode 2 and Model code 2010 present a good approach for the calculation, always with a small degree of overestimation for concrete without fibres. On the other hand, the values calculated using recommendations from NFP 18-710, the overestimation is higher. The influence of loading levels seems to not affect the number of cracks with an increase in concrete cover. The experimentally evaluated ranges to relate maximum and minimum spacing with the average value in a loaded region are given. No influence of using self-healing agents was detected.
Assessment of autonomous and autogenous healing on cementitious grouts promoted by additions of microcapsules and crystalline admixtures
Authors: da Rocha Gomes Suelen , Kumar Padmapryia A. , Rengaraju Sripriya , Al-Tabbaa Abir , Ferrara Liberato , Sánchez Luis , Sánchez Moreno Mercedes
Published: April 2023

The demand for more sustainable building materials has led to the development of systems with self-repairing properties. The self-healing technology has been shown to be effective in concrete and mortars, however, this technology is not often studied in grouts. Cementitious systems can show an autogenous healing, i.e., an intrinsic ability to repair microcracks by themselves. This type of healing can be improved by the addition of crystalline admixtures. In addition, the crack healing can also be enhanced by adding other materials, e.g., through the incorporation of polymeric microcapsules into the cementitious matrix that will promote a healing effect but, in this case, an autonomous healing. Thus, the main objective of this work is to assess the effect of the addition of microcapsules and crystalline admixture on viscosity and water capillary absorption of cementitious grouts. Cementitious grouts (w/b = 0.46 and w/b = 0.39) were prepared containing microcapsules (3% by weight of binder) and crystalline admixture (3% by weight of binder). Rheological measurements and water sorptivity tests were made. Viscosity measurements were taken at 3, 20 and 60 minutes. Sorptivity tests were performed on cracked specimens in order to quantify the healing efficiency. Cracks were created 7 and 28 days after casting and the water absorption was measured for 7, 14 and 28 days after cracking. The results showed that the viscosity changed considerably depending on the w/b ratio and the healing agent type. Among all grouts, reference grout presented the highest viscosity and grout with microcapsules and crystalline admixture the lowest. The water absorption of the grouts with microcapsules was the lowest regardless of curing age and w/b ratio. Regarding crystalline admixture, at both curing ages the water absorption was quite high.
Structural performance of reinforced concrete beams with self-healing cover zone
Authors: He Shan , Luković Mladena , Jonkers Henk , Schlangen Erik
Published: April 2023

In the current study, experiments were carried out to investigate the structural performance of reinforced concrete (RC) beams with a self-healing cover zone. The cover zone consists of a 1.5-cm-thick layer of bacteria-embedded strain hardening cementitious composite (SHCC) for a combination of crack width control and crack healing. The aim is to bring together two emerging technologies (i.e., self-healing and strain-hardening) that show great potential for realizing highly efficient concrete structures. RC beam without the self-healing cover was also prepared as the control specimen for comparison purposes. The experimental program includes loading the beams to failure in four-point bending configuration and sawing the beams to segments for crack pattern analysis and crack healing. Results show that the beams with selfhealing cover exhibited a 45-60% improvement in structural capacity. The crack patterns of the hybrid beams were also largely modified. While the reference beam formed only a few major cracks, the hybrid beams formed around 40 fine cracks in the constant bending moment region with an average crack width smaller than 0.2 mm even at maximum load. By having an improved cracking behavior and an enhanced self-healing capacity, it is expected that the beams with a self-healing cover will possess an extended service life at the expense of minimal additional cost.
Comparison of different types of self-healing concrete under extreme conditions
Authors: Cappellesso Vanessa G. , Van Mullem Tim , Gruyaert Elke , Van Tittelboom Kim , De Belie Nele
Published: April 2023

Extreme environments are aggressive for concrete structures, hence a performance-based design is crucial to guarantee the durability during the service life. Nonetheless, there is a knowledge gap regarding the influence of cracks on standard and self-healing concrete. This research focuses on monitoring cracked self-healing concrete with two commercial healing agents: a bacteria-based healing agent (BAS) and a crystalline admixture (CA). After crack formation and a healing process of three months in wet/dry conditions (4 days/3 days), several extreme conditions were considered: (1) submerged in artificial seawater, (2) submerged in a solution with 33 g/L sodium chloride and (3) freeze-thaw (FT) cycling with de-icing salts. Microscopic images were used to quantify the healing efficiency of the two different healing agents, while chloride ingress and scaling were measured to determine durability. The results of the microscopic measurements indicated significant healing efficiency for both healing agents after the healing regime reaching 72% for CA, and 67% for BAS. After exposure to a marine environment, this efficiency increased to 95% and 92%, respectively. The uncracked BAS samples achieved a scaling reduction of 93% under FT exposure relative to the uncracked REF samples, while this was 49% for the CA samples. In cracked samples, scaling was reduced by 50% for BAS and 24% for CA, relative to the cracked REF samples. In all tested conditions, the BAS samples partially prevented the chloride ingress through the crack, while CA samples showed a great reduction. Overall, both healing agents reduced the degradation and could decrease the chloride ingress.
The application of a curing front model to simulate healing in a cementitious microbial system
Authors: Jefferson Anthony , Freeman Brubeck
Published: April 2023

This study investigates the ability of a coupled finite element model to simulate Microbially Induced Calcium Carbonate Precipitation (MICP) and associated healing behaviour in cementitious samples. This recent coupled 3D model was first developed for simulating the behaviour of autonomic healing systems in cementitious structural elements. It employs a cohesive zone constitutive model for simulating the damage-healing behaviour of an embedded interface within 3D continuum elements. Fluid flow is simulated using a mass balance equation and Darcy’s law. Healing is computed via a generalised curing front model that simulates the accumulation of healed material within a crack. The research reported in this article demonstrates that the curing front model can be calibrated to predict healing from MICP in cementitious specimens with good accuracy.
A scientific rationale for the enhanced sequestration of CO2 in concrete
Authors: Kamde Deepak K. , Kwasny Jacek , Russell Mark I. , Muhammed Basheer P.A.
Published: April 2023

Oxford Economics forecasts that concrete construction will grow by 85% to USD 8 trillion worldwide by 2030 and will lead to significant usage of Portland cement (PC). Every 1 kg of PC production generates ≈0.8 kg of CO2, which is about 1.5 Gt of CO2 emission per year for PC production. One of the ways to reduce the carbon footprint of concrete is by sequestrating CO2 using of the following approaches: (i) pre-carbonation; (ii) wet-carbonation; or (iii) CO2 curing of concrete in various types of carbonation chambers. The efficiency of these methods is measured by calculating CO2 Sequestration Factor (CSF). It is reported that the CSF of carbonation curing approach is 10 to 15%. However, it was found that the method used for calculating CSF does not consider the un-carbonated parts of the specimens, hence it does not represent the actual efficiency of the CO2 sequestration methods. Therefore, modification for calculating the CSF is proposed in this paper. Using the modified method, it was found that the CSF of carbonation curing method is less than 2% and wet carbonation is the most efficient method (≈30%). Further, a way forward is proposed to enhance the CO2 sequestration in concrete, which will not compromise fresh or hardened properties of concrete and would significantly contribute to the net zero carbon agenda compared to existing approaches
The impact of digital financial inclusion on enterprises’ innovation ability in China empirical evidence from high-tech SMEs
Authors: Wu Wanqi
Published: April 2023

Taking the technology-based SMEs as the research object, the principal component analysis method is utilized to construct the enterprise innovation capability index. The research shows that the development of digital inclusive finance has a significant positive impact on innovation capability, and the positive effect is still significant under the robustness test. However, there is no intermediary effect of financing constraints in the segmented market of small and medium-sized technology-based enterprises, which is partly due to the difficulty of efficient project identification of the digital inclusive platforms with mixed advantages and disadvantages in the market. The lag effect indicates that the impact of digital inclusive finance on the innovation of technology-based SMEs will be more obvious after a period of time.
Analysis of Turkey’s Detrending Economics Using the Hodrick-Prescott Filter
Authors: Ma Weiyue
Published: April 2023

This paper aims to analyze the effectiveness of detrending policies in Turkey using the Hodrick- Prescott (HP) filter, the country’s Gross Domestic Product (GDP), and selected indicators from 2010 to 2021. The HP filter is a commonly used statistical tool for detrending time series data by separating the trend component from the cyclical component of a series. The discussion section shows the observable and physical impact of overlooking the cyclical components over the trend components. It also contains verifiable facts from several trustworthy sources showing the precise impact of detrending the economy. The final section of this work contains the final results and recommendations that make up the entirety of this work’s body. By analyzing the trend in GDP and selected indicators such as inflation, exchange rate, and unemployment rate, we can gain insights into how Turkey’s economy has been affected by detrending policies; and provides a basis from which better policies can be founded.
An empirical study on the influence of institutional cross-shareholding on the innovation of listed companies
Authors: Wang Wen , Zhang Cong Zhi
Published: April 2023

In this paper, we study the impact of cross-shareholdings of listed companies institutions innovation and mechanism of action, and use computer and related technology combined with econometrics, adopt OLS regression analysis and intermediary effect inspection and so on model, based on China’s a-share listed companies from 2007 to 2020 data, cross-shareholdings of listed companies to institutional innovation influence the empirical analysis. It is found that institutional cross-shareholding mainly improves innovation input and output by alleviating financing constraints, and the conclusion is still robust after considering the endogeneity problem.
Energy storage economy research and sensitivity analysis applied to photovoltaic primary frequency modulation scenario
Authors: Zhao Song , Zhou Lei , Dang Shaojia , Li Xu , Zhao Wei , Zhang Qian , Du Ronghua , Huo Hongyan , Xin Xiaogang , Zhang Guobin , Guo Ruijun , Yin Jianhua , Yu Haicun , Li Rongli , Qin Chengguo , Li Qiuping
Published: April 2023

In practical engineering applications, the investment, income, subsidies and other costs of energy storage batteries have a certain impact on the overall economic benefits of primary frequency modulation. The larger the capacity of the configured battery energy storage system, the better the primary frequency modulation effect will be, but at the same time, the problem is that the cost of investment in the energy storage system will increase, which will offset the benefits of primary frequency modulation loss reduction of its auxiliary photovoltaic station from an economic perspective. Therefore, this paper will clarify the benefits and costs of the primary frequency modulation application environment of the energy storage system, and establish an economic analysis model from delaying the investment of photovoltaic station equipment, reducing the cost of light waste, environmental benefits, direct benefits, government subsidies, energy storage investment costs and other aspects. Finally, a photovoltaic station is taken as an example to simulate and analyse the sensitivity.
The Impact of China’s OFDI on Inclusive Growth across Countries
Authors: Fu Shiyun
Published: April 2023

Since the twentry-first century, deepening globalization has not only promoted the prosperity of international trade and investment and has led to many global crises. Faced with the looming threats, the Asian Development Bank first proposed the concept of “Inclusive Growth”, aiming to foster more inclusive and beneficial economic growth and reduce income disparity. As a substantial, lasting international investment, often with specific strategic purposes, FDI, especially China’s OFDI, includes not only capital investment but the provision of management, technology, and equipment, thus will affect the host countries’ pattern of economic activities and further have the consequent impact on the economy, society, and environment of the host countries. This paper uses a panel two-way fixed effects model to explore whether China’s OFDI promotes inclusive growth in host countries. It shows that China’s OFDI significantly promotes inclusive growth in host countries, and the instrumental variable method results support the findings’ robustness. Further, the heterogeneity analysis shows that the effect of China’s OFDI is mainly concentrated on coastal countries, members of the OECD, and high-income economies. This study is important for a deeper understanding of the impact of China’s OFDI on host countries’ inclusive growth worldwide.