bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a standard for accelerated determination of frost resistance of autoclaved aerated concrete
Authors: Lapovska Svitlana , Klapchenko Vasyl , Demchenko Tetyana 
Published: September 2023

AbstractIntroductionThe “Introduction” analyses the mechanisms of concrete frost damage and describes standard methods for determining the frost resistance of lightweight and cellular concrete.Research methodsThe frost resistance at different freezing temperatures was carried out on samples of autoclaved cellular concrete of D400 to D600 density. Specimens with dimensions of 100 × 100 × 100 mm were cut from prefabricated parts in accordance with EN 771‐4. During the experiment, frost resistance of ААС samples was determined at a standard temperature of −18 ± 2°C, as well as at temperatures from −5°C to −40°C4.Results and discussionIn the paper, frost resistance of concrete at various freezing temperatures was evaluated by the experimental‐analytical method, which is based on the assumption that frost resistance, expressed in the number of cycles (F) should be inversely proportional to the volume of frozen water at this temperature.The frost resistance of concrete was evaluated experimentally and analytically at different freezing temperatures, assuming that the frost resistance (F), expressed in the number of cycles, should be inversely proportional to the volume of frozen water at that temperature V(t).Determination of the rate of ice spreading front and moisture diffusion in building materials by conductometric method during one‐sided freezing allows a more detailed study of the mechanisms of frost failure of building materials.ConclusionsThe proposed experimental‐analytical method for evaluating AAC frost resistance at different freezing temperatures allows, with a small expenditure of time, to obtain more complete information on the material behavior in freezing temperatures than it is provided by the existing standard methods. The analysis of the dependence of freezing resistance on temperature also allows revealing the regions of temperature where it changes most strongly, and to shift, if necessary, these regions towards lower or higher temperatures by adjusting the composition and technology of AAC production.The developed combined method of independent measurements of moisture diffusion kinetics and ice content makes it possible to determine the speed of diffusion of ice formation front and moisture conductivity depending on the composition (capillary‐porous structure) of samples and their initial storage conditions. This information can give a more reliable picture of the behaviour of AAC under alternating temperature loading under varying initial moisture conditions.
Full‐scale studies of stiffening walls made of autoclaved aerated concrete
Authors: Grzyb Krzysztof , Jasiński Radosław 
Published: September 2023

AbstractAutoclaved aerated concrete is successfully produced as masonry units to construct single and multi‐family houses. Residential buildings are often erected as load‐bearing structures. Although designers are used to verifying the masonry structure for mainly vertical loads, some elements must act as a stiffening of the building. Horizontal loads of the building can be caused not only by wind pressure and suction but also by uneven subsidence of the ground or mining influences. The role of the stiffening walls is to ensure the geometric invariability of the building and the safe transfer of horizontal loads to the foundations. The Silesian University of Technology conducts extensive research on stiffening walls on full‐scale models of single‐storey buildings. Experimental analyzes enable the description of the propagation and morphology of cracks. Designation of the behavior phases of the stiffening walls is the basis for developing the calculation methodology for stiffening elements.
Use of load‐bearing AAC panels in transportable, prefabricated, pre‐finished, modular housing
Authors: Puzey Adrian , Balding Tony 
Published: September 2023

AbstractThis article will outline a method of building residential homes as Prefabricated, Prefinished Volumetric Construction (PPVC), using AAC panels. These transportable structures are created from solid AAC modules and designed for Residential Homes and Low‐Rise multi‐residential developments. In this transportable system, thick AAC panels are used as the principal construction material and load‐bearing structural element. The AAC modules are factory assembled and fitted out as completed room pods. They are transported to the site where they are lifted directly from the delivery truck and positioned into their final location on steel piers. Engineered AAC floor and ceiling cassettes connect the modular pods together to form a spacious and modern solid AAC home.
Industrial automation and robotics in AAC industry: Selected models and case studies
Authors: Aldarrat Hatem , Drosten Gerrit 
Published: September 2023

AbstractAs the global manufacturing industry entered its fourth revolution (4IR, or Industry 4.0), innovations such as robotics, automation, and artificial intelligence are set to take over and improving the global industries. As the number of active industrial robots worldwide is increasing every day in different applications and industries automation continues to create new types of robots with improved utility and function. In the AAC Industry, these innovations already took place for some time in different process phases and applications such as oiling, autoclaves stacking pins, handling, packing, and so forth. Through this research, advantages commonly attributed to automation and robotics include higher production rates and increased productivity, more efficient use of materials, better product quality, improved safety, shorter workweeks for labor, and reduced factory lead times. Especially reduced scrap and waste through improved accuracy, increased efficiency, and operation around the clock could be emphasized. Based on the accumulated experience of WKB Systems GmbH in the field of the forging industry, selected models, real‐life application case studies, and implementation of different robotics in the AAC industry are discussed in this paper. These examples such as linear robots for autoclaves stacking pins, articulated robots for AAC packing and sorting line, and hybrid systems for handling and packing AAC insulation boards are studied in detail.
Calculation of EPD for individual AAC product classes
Authors: Walther Hartmut B. 
Published: September 2023

AbstractIn fact, climate change is increasing the relevance of Environmental Product Declarations (EPDs). Currently, product‐specific EPDs are coming into vogue instead of average‐based EPDs. Individual EPDs for distinct products can be beneficial, but the data preparation upfront is crucial to avoid greenwashing through the use of false data. Adjustments to the standards for calculating EPDs are currently under development.The starting point for the calculation of EPD according to EN 15804+A2 is always the annual production and associated consumption of raw materials and energy. The raw material input per product is calculated from recipe data and the respective production quantities as a first step. This shall be done for all products of a plant. Now, the summarized consumptions have to be related with the purchased raw material quantities, correction factors have to be calculated and applied to specify the actual input per product. The use of correction factors is mandatory to avoid inaccuracy and underestimation of actual consumption. Hence, the calculation of one product‐specific EPD requires product‐specific source data preparation for all products.In AAC production, the correction of the consumed raw materials is particularly important concerning internal recycling. For example, the actual consumption of aluminum is of specific interest. While ground sand within the recycled sludge is unchanged and binders still react in the autoclave, the aluminum is no longer reactive. This can lead to additional aluminum consumption that deviates by one‐third and more from the recipe values.In the presentation, a comprehensive approach to the calculation of correction factors for different AAC product classes will be introduced. The final calculations for the EPD are not based on recipe data alone but are corrected using procurement data. Thus, the total consumption of a plant can be adequately allocated to all products in the production program.
Influence of carbon dioxide on shrinkage behavior and compressive strength of AAC in accelerated tests
Authors: Rzeczkowski Patrick , Lohaus Ludger 
Published: September 2023

AbstractBackgroundThe German application standard DIN 20000‐404:2018‐04 for the use of AAC according to DIN EN 771‐4:2015‐11 describes a method to determine the long‐term resistance due to carbonation. Thus, the total value of the drying shrinkage as specified in DIN EN 680:2006‐03 must not exceed 0.40 mm/m. This threshold was evaluated using empirical methods.ObjectiveIn order to verify the above threshold, additional studies were carried out in this paper on AAC blocks from different manufacturers.ExperimentalDeviating from the standard climate according to DIN EN 680:2006‐03, a parametric study was carried out under laboratory conditions. All AAC specimens were stored at a relative humidity of 80% and a carbon dioxide concentration of 0.5% by volume. In addition to the shrinkage behavior, the compressive strength behavior of the AAC specimens with increasing carbonation progress was investigated.ResultsThe degree of carbonation of the individual AAC types progresses at different rates. AAC that carbonates faster shows a greater change in length (up to about 5.2 mm/m) and a significant loss in compressive strength (up to about 50%). In some cases, the compressive strength initially increases before decreasing again. AAC containing fly ash only shows an increase in compressive strength with progressive carbonation.ConclusionsThe determination of the total value of drying shrinkage according to DIN EN 680:2006‐03 appears to be the most suitable method so far to identify AAC blocks with an increased risk towards carbonation with a manageable effort. The accompanying compressive strength tests indicate that the specified limit value of 0.40 mm/m according to DIN 20000‐404:2018‐04 is also appropriate.
CO2 – Quo Vadis? If CO2 emission is really an ecological indicator of green production?
Authors: Walczak Paweł 
Published: September 2023

AbstractReduction of CO2 emission has been a main topic in all sectors of our life for many years, and one of the most important milestones in a lot of companies, like in the building sector. It is commonly known that carbonation of building materials based on cement and lime is a natural process. Due to this fact, these materials can be eco‐friendly because they can absorb CO2 from the atmosphere. Autoclaved aerated concrete sample with a density class 600, from different producers, and with different compressive strengths: 3.0, 4.0, and 5.0 N/mm2, and density class 500: 2.5 and 4.0 N/mm2 were the subject of this research program. The analysis of phase composition and observation under SEM microscope clearly showed the correlation between compressive strength and the amount of calcium silicate hydrates (C‐S‐H phase) formed under hydrothermal conditions, mainly tobermorite. Tobermorite content in AAC depends on the amount of binder used for its production. The performed calculations showed that not always the material with the lowest carbon footprint is the most eco‐friendly product because when looking at CO2 emissions, one can forget about rational management of natural resources.
Experimental behavior of lintels for AAC masonry buildings: Comparison among different solutions
Authors: Ferretti Daniele , Cerioni Roberto , Riva Andrea , Boretti Giovanbattista , Casillo Alfredo , Michelini Elena 
Published: September 2023

AbstractThe paper investigates the experimental behavior up to failure of different types of lintels for AAC masonry buildings. At first, precast highly‐reinforced AAC lintels, that are quite widespread on the European and Turkish market, were tested in flexure, by considering different reinforcement type and arrangement. The second analyzed solution is represented by RC lintels cast within three juxtaposed special AAC elements with U section, acting as formwork and final external finishing. Also in this case, the effect of reinforcement type (lattice girders, ordinary rebars, or a combination of them) and reinforcement amount on the bearing capacity and mode of failure was analyzed. The experimental results highlight that precast AAC lintels available on the market are very light and are characterized by high stiffness in bending; however, being usually over‐reinforced, their failure is quite brittle. On the contrary, RC lintels cast within U‐shaped AAC blocks (“combined AAC‐RC” specimens) are heavier but can be easily designed to have a ductile behavior, by simply following design Standard recommendations for ordinary RC elements.
Study of the solubility of xonotlite
Authors: Mingione Serena , Lothenbach Barbara , Winnefeld Frank , Opsommer Ann 
Published: September 2023

AbstractXonotlite (Ca6Si6O17(OH)2) is a hydrated crystalline calcium silicate with CaO/SiO2 = 1, which forms under hy‐drothermal conditions at temperature above ∼100°C. It has good thermal stability, it dehydrates to wollastonite only at 770 to 800°C and shows a good resistance to high pressures. Deposits of xonotlite are rare in nature, but it can easily obtained by hydrothermal synthesis in the temperature range of 180 to 350°C. Several studies have been conducted to better understand the formation conditions of xonotlite in terms of optimum temperature, duration and starting materials, but very little is known about its solubility under different conditions. The two solubility data sets available in literature differ by as much as 10 log units with no clear reason for this difference. The aim of the present study is to determine the solubility of xonotlite at 20°C and to compare this data with the available data in literature. To achieve this goal, solubility experiments from undersaturation were carried out at ambient temperature (20°C). Thermodynamic modelling was used to calculate the solubility product of xonotlite based on the measured total aqueous concentrations. The derived solubility of xonotlite is comparable to the solubility previous reported for synthetic xonotlite at 25°C. The synthesized xonotlite is several log units more stable than the solubility reported in literature for natural xonotlite, which seems to describe rather the solubility of amorphous C‐S‐H.
Structural performance of aged Reinforced Autoclaved Aerated Concrete (RAAC) roof panels
Authors: Goodier Chris , Cavalaro Sergio , Gorse Chris , Blay Karen , Blanco‐Alvarez Ana 
Published: September 2023

AbstractReinforced Autoclaved Aerated Concrete (RAAC) is a lightweight, aerated cementitious material with no coarse aggregate, hence the material properties and structural behavior vary significantly compared with “traditional” reinforced concrete. It was a popular form of precast concrete panelized construction in the 1970s, especially in critical infrastructure such as hospitals, schools, and government buildings, and many of these structures are now at the end of their design life.Although the quality of contemporary RAAC precast elements and structures is considered to be good, concerns exist regarding the durability, serviceability and structural reliability of 40–50 year old RAAC panels still in service.Ongoing survey regimes and preliminary site observations and investigations of multiples structures in the United Kingdom have revealed significant problems in a small number of panels such as excessive cracking and deflection, insufficient cover, and reinforcement that is corroding and/or incorrectly placed.This paper therefore presents data on the structural performance and integrity of aged RAAC panels from the 1960s and 70s still in service in the United Kingdom, and presents the outcomes of the most significant and largest research project in the United Kingdom in the last 10 years, which investigated the material properties, structural performance, and monitoring strategies of aged RAAC panels. Structural testing on full scale panels in the laboratory and in situ have been conducted, together with petrographical examination and computational finite element modeling of RAAC panels form different structures and locations around the United Kingdom.The research has developed considerable new knowledge and understanding regarding the structural and material performance of aged RAAC panels and their associated failure modes, which will have significant implications for the repair, monitoring and management of these national critical infrastructure.
Tunable Regioselectivity in C−H‐Activated Direct Arylation Reactions of Dithieno[3,2‐b:2’,3’‐d]pyrroles
Authors: Vogt Astrid , Stümpges Florian , Bajrami Jessi , Baumgarten Daniel , Millan Judith , Mena‐Osteritz Elena , Bäuerle Peter 
Published: September 2023

AbstractIn this study, regioselectively controlled direct arylation of dithieno[3,2‐b:2,3’‐d]pyrroles (DTPs) is reported. By carefully selecting the catalytic system, Pd source, ligand, and additives, we achieved either selective N‐arylation or unprecedented β‐arylation and β,β′‐diarylation of the DTP core through C−H activation when reacting unsubstituted H‐DTP with 9‐anthracenyl halides. For N‐substituted DTPs, we obtained regioselective carboxylate‐assisted arylation of the α‐position(s). Consequently, depending on the catalytic system and substitution at the DTP nitrogen, we successfully synthesized novel regioselectively substituted DTPs, including N‐aryl, rarely reported β‐aryl, β,β’‐diaryl, α‐aryl, and α,α‘‐diaryl scaffolds. These compounds can be straightforwardly prepared and further functionalized for applications as organic electronic materials.
Cage‐Shaped Phosphites Having C3‐Symmetric Chiral Environment: Steric Control of Lewis Basicity and Application as Chiral Ligands in Rhodium‐Catalyzed Conjugate Additions
Authors: Liu Xiao , Tomita Kazuma , Konishi Akihito , Yasuda Makoto 
Published: September 2023

AbstractDesigning chiral ligands with an axial symmetry higher than C2‐rotational symmetry is one of the most crucial approaches to improving enantioselectivity in asymmetric synthesis. Herein, C3‐symmetric chiral cage‐shaped phosphites are reported. Their Lewis basicity and chiral environment are precisely controlled by the tethered group. The cage‐shaped phosphites successfully worked as chiral ligands in Rh‐catalyzed asymmetric conjugate additions, realizing acceptable yields with excellent enantioselectivity, and were used to synthesize a pharmacologically important molecule.
Circulating Th17/Treg as a promising biomarker for patients with rheumatoid arthritis in indicating comorbidity with atherosclerotic cardiovascular disease
Authors: Fan Hongxuan , Zhao Jianqi , Mao Shaobin , Wang Yongle , Wang Miao , Song Xiaosu , Liu Gaizhen , Wang Caihong , Wang Xin , Liang Bin 
Published: September 2023

AbstractBackgroundImmune and inflammatory responses have a pivotal role in the pathogenesis of rheumatoid arthritis (RA) and atherosclerotic cardiovascular disease (ASCVD). This study aims to explore the change of peripheral lymphocytes, especially the absolute and relative changes in peripheral T cells in RA patients with and without ASCVD.HypothesisThe changes in the lymphocyte subsets were assessed to provide a novel insight in diagnosing and preventing ASCVD in patients with RA.MethodsA propensity score matching system (1:1) was conducted to perform a matched case–control study with 169 pairs RA‐ASCVD and RA participants. Univariate and multivariate analyses were performed to determine the association between peripheral lymphocytes and RA‐ASCVD.ResultMultivariate logistic regression analysis demonstrated that Th17 cell absolute, Th17 cell Ratio, Th17/Treg were associated with a significantly higher risk of ASCVD after model adjustment. Then we focused on Th17/Treg, multivariate logistic analyses in tri‐sectional Th17/Treg groups showed that the odds of ASCVD is gradually increasing with Th17/Treg rank's rising after model adjustment. Finally, the restricted cubic spline of Th17/Treg and odds ratio of RA‐ASCVD was conducted. Interestingly, we found a critical point of Th17/Treg (critical point = 0.2399). Th17/Treg shows a protective role in the odds of ASCVD when Th17/Treg < 0.2399. With smaller Th17/Treg, the protective efficiency is more obvious when Th17/Treg < 0.2399.ConclusionsOur study suggested that increasing absolute and percentage of Th17 cells in the peripheral blood of patients with RA was associated with the development of ASCVD. And Th17/Treg may be a promising biomarker for patients with RA in indicating comorbidity with ASCVD.
Novel, computational IgE‐clustering in a population‐based cross‐sectional study: Mapping the allergy burden
Authors: Czolk Rebecca , Ruiz‐Castell Maria , Hunewald Oliver , Wanniang Naphisabet , Le Coroller Gwenaëlle , Hilger Christiane , Vaillant Michel , Fagherazzi Guy , Morel‐Codreanu Françoise , Ollert Markus , Kuehn Annette 
Published: September 2023

AbstractBackgroundEven though the prevalence of allergies is increasing, population‐based data are still scarce. As a read‐out for chronic inflammatory information, new methods are needed to integrate individual biological measurements and lifestyle parameters to mitigate the consequences and costs of allergic burden for society.MethodsMore than 480.000 data points were collected from 1462 Luxembourg adults during the representative, cross‐sectional European Health Examination Survey, spanning health and lifestyle reports. Deep IgE‐profiles based on unsupervised clustering were correlated with data of the health survey.Findings42.6% of the participants reported a physician‐diagnosed allergy and 44% were found to be IgE‐positive to at least one allergen or extract. The main sensitization sources were tree pollens followed by grass pollens and mites (52.4%, 51.8% and 40.3% of sensitized participants respectively), suggesting seasonal as well as perennial burden. The youngest group of participants (25–34 years old) showed the highest burden of sensitization, with 18.2% of them having IgE to 10 or more allergen groups. Unsupervised clustering revealed that the biggest cluster of 24.4% of participants was also the one with the highest medical need, marked by their multi‐sensitization to respiratory sources.InterpretationOur novel approach to analyzing large biosample datasets together with health information allows the measurement of the chronic inflammatory disease burden in the general population and led to the identification of the most vulnerable groups in need of better medical care.
A Review of Polymer Electrolyte Fuel Cells Fault Diagnosis: Progress and Perspectives
Authors: Zhou Shangwei , Jervis Rhodri 
Published: September 2023

AbstractPolymer electrolyte fuel cells (PEFCs) are regarded as a substitution for the combustion engine with high energy conversion efficiency and zero CO2emissions. Stable system operation requires control within a relatively narrow range of operating conditions to achieve the optimal output, leading to faults that can easily cause accelerated degradation when operating conditions deviate from the control targets. Performance recovery of the system can be realized through early fault diagnosis; therefore, accurate and effective diagnostic characterisation is vital for long‐term serving. A review of off‐line and on‐line techniques applied to the fault diagnosis of fuel cells is presented in this work. Off‐line approaches include electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), galvanostatic charge (GSC), visualisation‐based and image‐based techniques; the on‐line methods can be divided into model‐based, data‐driven, signal‐based and hybrid methods. Since each methodology has advantages and drawbacks, its effectiveness is analysed, and limitations are highlighted.