bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of clay impurities on the performance of calcined clay‐limestone cements
Authors: Matschei Thomas , Muzenda Tafadzwa Ronald , Georget Fabien
Published: December 2023

The use of blended cements including novel supplementary cementitious materials is the most powerful lever to cut down the carbon footprint of cementitious materials. This has led to an increased interest in research on calcined clay limestone cement (CCLC) over the last years. In this study, we investigate the fresh and early hydration properties of CCLC using kaolinitic clays with a wide range of chemical and mineralogical compositions, which are all of industrial origin. Results show that early performance of calcined clays is not only dependent on kaolinite content but that the total specific surface area of the raw and calcined clays plays a key role in the onset and evolution of rheological properties as well as early hydration and reactivity. Further analysis indicated that among secondary mineral impurities, iron phases affect the physiochemical properties of calcined clays. This is shown by the high specific surface area of these clays. It appears possible that by causing higher kaolinite structure disorder, iron phases also impact hydration.
Spatially resolved in situ analyses of the adsorption behavior of different admixtures on binders
Authors: Kosenko Denis , Wetzel Alexander , Middendorf Bernhard
Published: December 2023

Admixtures play a key role in improving the performance of the cement paste matrix. A more efficient matrix can allow a reduction the binder content while maintaining the same properties. There is currently a lack of knowledge about the spatial distribution of admixtures in situ on binder surfaces which would facilitate the use of admixtures in general in inorganic binder systems. Imaging techniques such as confocal laser scanning microscopy (CLSM) and fluorescence microscopy can be used to study the spatiotemporal adsorption of superplasticizers and plasticizers on binder particles. However, in order to make the admixtures visible using these methods, they must first be coupled to a fluorescent molecule (staining). Different types of superplasticizers and plasticizers, including polycarboxylate ethers (PCE) and lignosulfonate (LS) were stained and tested. It was shown that not only adsorption but also desorption can be observed and that desorption cannot play a relevant role in a binder system. The absence of desorption could be used to observe a real system in permanent preparations, so that the adsorption on individual cement grains could be followed in a time‐dependent manner. The newly developed method provides unprecedented insight into the adsorption of additives.
Mastering the rheology of fresh concrete: New knowledge from a DFG priority program SPP 2005
Authors: Mechtcherine Viktor
Published: December 2023

The processing of cement‐based building materials represents the technological core in the construction and maintenance of structures. However, a scientific framework for mastering rheology‐based processes is still in an early stage of its development. The reason for this is the extremely high complexity of cementitious systems. This complexity includes the high chemical reactivity of mineral binders, the complex multi‐phase nature of fresh concrete or mortar, and a wide range of deformation rates during various technological processes, which result in extremely high demands for characterization and simulation methods. The goal of the DFG Priority Program SPP 2005 “Opus Fluidum Futurum – Rheology of reactive, multiscale, multiphase construction materials” is to ascertain and describe the scientific fundamentals for understanding and, subsequently, designing rheology‐based construction processes as well as for developing innovative, sustainable building materials and associated pioneering processing technologies. The article at hand presents the purpose and the structure of the collaborative research as well as the achievements of the priority program. Furthermore, it offers some insights into ongoing and planned research.
Rückführung von Gipsformenabfällen in den Produktionskreislauf der Porzellanindustrie
Authors: Dreuse Heike , Nowak Saskia , Geithe Rigo , Zier Hans‐Werner
Published: December 2023

Kurzfassung

Im Rahmen eines zweijährigen Forschungsprojektes hat die Materialforschungsund –prüfanstalt an der Bauhaus‐Universität Weimar (MFPA) gemeinsam mit der Porzellanmanufaktur Reichenbach (PMR) Lösungen dafür entwickelt, inwiefern Gipsformen, die zur Herstellung von Porzellangegenständen verwendet werden, nach ihrem Verschleiß durch mechanische und thermische Aktivierung wieder zur Herstellung neuer Gipsformen genutzt werden können. Im Ergebnis der umfangreichen Untersuchungen konnte aus mehreren geeigneten Aufbereitungsschritten eine optimierte Verfahrensweise herausgearbeitet werden, um praxisnah Recycling‐Gips zu gewinnen, daraus wieder ein verarbeitungsfähiges Bindemittel herzustellen und robuste Gipsformen aus 100 % Recycling‐Gips mit einwandfreier Oberfläche zu fertigen. Ein solcher Kreislauf ist unter Beachtung der erarbeiteten Kriterien mehrfach ohne Qualitätseinbußen durchführbar und lohnt sich für den Betrieb trotz des etwas schnelleren Verschleißes der Gipsformen aus RC‐Gips.
KI‐gestützte Klassifikation von Gipsgesteinen auf Basis der hyperspektralen Bildgebung im SWIR
Authors: Hunhold Patrick , Linß Elske , Nowak Saskia
Published: December 2023

Kurzfassung

Der effiziente Einsatz begrenzter Ressourcen spielt eine immer wichtigere Rolle, wenn es um das nachhaltige Wirtschaften geht. Mit der Beendigung der Kohlever‐stromung bis zum Jahr 2038 und dem damit verbundenen Wegfall von REA‐Gips, verliert die Gipsindustrie eine wesentliche Quelle für ihre Produkte. Dieser Wegfall kann nicht annähernd mittels Gipsrecycling kompensiert werden. Ein vermehrter Abbau von Naturgips und –anhydrit ist in Bezug auf den Naturschutz kritisch zu hinterfragen. Diese Arbeit setzt sich daher insbesondere mit der Klassifikation von bisher ungenutzten Gipsgesteinen (Übergangsgesteine) auseinander, welche ohnehin beim Abbau von Naturgips anfallen. Als Methode der Wahl wird auf die hyperspektrale Bildgebung zurückgegriffen, mit dessen Hilfe es möglich ist räumliche und spektrale Informationen zu gewinnen und diese mit Verfahren des maschinellen Lernens zu kombinieren. Die bisherigen Ergebnisse von mehr als 99 % Erkennungsrate machen zuversichtlich, dass diese Methode sich durchaus eignet. Optimierungsbedarf besteht dagegen in der Erkennung der Mineralphasen im Übergangsgestein selbst.
Rheological Investigation of a Set of PCE Superplasticizers in Cement
Authors: Wagner Thomas , Gädt Torben
Published: December 2023

The importance of polycarboxylate ethers (PCE) as concrete superplasticizers has significantly increased in recent decades, both technically and commercially. At the least, three descriptors describe the average PCE structure: the side chain length (P), the charge density (N), and the number of repeating units (n). The synthesis parameters determine the average composition of the PCEs and, consequently, their performance in cementitious materials. This study examines the rheological properties of 27 different PCE structures, which were synthesized using redox‐initiated free‐radical copolymerization. We independently varied the parameters P and N and produced three PCEs with different molar weights for each combination of P and N. Cement pastes with low PCE dosages of 0.035 wt% were tested in a rheometer using a plate‐plate geometry. It turns out that when the PCE is added directly to the mixing water, the PCE has a complex influence on the very early hydration. Consequently, the obtained rheology data is not entirely in line with available structure‐activity relationships. Additionally, we attempted to model the observed rheology data based on three structural PCE descriptors. While a multivariate linear regression model failed to accurately describe the relationship, a random forest model delivered a better model. In summary, we conclude that the impact of PCEs on early hydration significantly affects the rheology of the paste. The changed hydration pathway causes a deviation of our results from existing structure‐activity relationships and makes it challenging to statistically model the sparse rheology data with a minimal set of three structural descriptors.
Leichter Schaumstein aus groben Porenbetongranulaten im zweiten Nutzungszyklus – RC‐Schaumstein
Authors: Hlawatsch Frank , Peters Maike , Ufermann‐Wallmeier Daniel
Published: December 2023

Kurzfassung

Schüttungen aus groben Porenbeton‐Granulaten lassen sich durch eine mineralische Schaummörtelmatrix zusammenfügen und bilden so den „Schaumstein aus groben Porenbetongranulaten“, dessen Eigenschaften dem Primärprodukt Porenbeton stark ähneln. Porenbetonbruch kann so vor der Deponierung verschont bleiben und bietet stattdessen die Möglichkeit zur Herstellung eines ressourceneffizienten, klimaschützenden Recyclingbaustoffes mit beachtlichem Wertschöpfungspotenzial. Im Zuge der Weiterentwicklung des Schaumsteines ist es gelungen den Nachweis dafür zu führen, dass das Recycling‐Produkt „Schaumstein” mit derselben verfahrenstechnischen Vorgehensweise abermals recycelt werden kann zum „RC‐Schaumstein“ wobei dessen Baustoffeigenschaften auf selbem Niveau bleiben.
Sanieren und Verstärken mit Carbonbeton – Materialkennwerte und Anwendungsgebiete des CARBO‐refit®‐Verfahrens
Authors: May Maximilian , Schumann Alexander , von Daake Henning
Published: December 2023

Kurzfassung

Das CARBOrefit®‐Verfahren steht für nachhaltiges und ressourcenschonendes Sanieren und Verstärken mit dem innovativen Hochleistungsbaustoff Carbonbeton: Aufgrund der Korrosionsbeständigkeit der Carbongitter können bestehende Stahlbetonbauwerke im Vergleich zu konventionellen Methoden mit sehr dünnen Carbonbetonschichten instandgesetzt werden. Mit der allgemeinen bauaufsichtlichen Zulassung (abZ) / allgemeinen Bauartgenehmigung (aBG) Z‐31.10‐182 ist das CARBOrefit®‐Verfahren bauaufsichtlich geregelt und anwendbar. Den planenden und ausführenden Unternehmen steht ein anerkanntes Verfahren zur Verfügung, mit welchem effiziente Lösungen realisiert werden können. Der Erhalt von Bauwerken und deren Weiternutzung hat oft nicht nur einen historischen Mehrwert, auch ökonomische und ökologische Vorteile gehen damit einher. Verschiedenste Stahlbetonkonstruktionen, sei es im Hochbau oder Ingenieurbau, wurden bereits mit diesem Verfahren saniert und die Anwendbarkeit konnte nachgewiesen werden. Statische Defizite des Bestandes können mit CARBOrefit® behoben und die Tragfähigkeit erhöht werden. Daneben kann auch die Dauerhaftigkeit von Stahlbetonbauwerken mit Carbonbeton verbessert werden.
Removal of asbestos as an intrusive contaminant from concrete construction waste
Authors: Thakur Jha Rani Kumari , Zimmermann Nico , Schaudienst Falk , Vogdt Frank Ulrich
Published: December 2023

The construction industry is the world's largest and fastest‐growing industry due to the increase in population, standards of living, and the higher demand for infrastructure. This fast growth generates huge amounts of construction and demolition waste (C&D waste), which amounts to more than 25% of the total generated waste, which has become a serious environmental challenge that needs to be addressed. The asbestos content in C&D waste poses a health risk and is entitled to special care, however, disposal of asbestos as hazardous waste is the only option by law. The present paper suggests the selective demolition of asbestos‐containing demolished waste rubble to be disposed of in compliance with all local and state regulations and proposes non‐asbestos rubble fraction to be recycled as an alternative sustainable management option that mitigates different adverse environmental impacts of the presently used conventional C&D waste management method.
Hydration mechanism of special‐purpose cements
Authors: Shabanova Halyna , Korohodska Alla
Published: December 2023

During baking of the raw mixture, a weak crystallization of hydraulically inert compounds is observed for these materials, providing a substrate for the growth of hydraulic compound crystals with limited solid solutions. As a result of grinding, cleavage of crystals will occur along the growth steps and intercrystalline boundaries, creating additional mechanical stress concentrators, which provides an increase in hydraulic activity. It appears that the full destruction of solid solutions does not occur, which results in strength enhancement of resulting hardened cement stone. The electron defects can also occur, having the form of deviations from distribution of electric charge corresponding to the regular structure of crystals. Upon hydration of the cements obtained from clinkers, highly basic hydrated newgrowths and active hydroxides are formed. At the same time, some leaching occurs on the surface of hydraulically inert compound resulting in a gelatinous hydroxide. With the lapse of time, gelatinous hydrate newgrowths transform to a crystalline state with decrease of basicity and lattice rearrangement into a more closely packed one. Amorphous hydroxides undergo crystalline aging and form a compactive crystallization frame around the grains of alkaline‐earth hydroaluminates.
Influence of Carboxylic Acids on the Nucleation of Cementitious Phases Studied by Titrimetric Methods
Authors: Vohburger Andreas , Gädt Torben
Published: December 2023

It is important to accurately control the setting of concrete and mortars. Functional admixtures such as hydroxy carboxylic acids can modify the hydration mechanism by influencing the dissolution of clinker phases and the crystallization of hydrate phases. While the crystallization of phases like CaCO3 under the influence of various additives has been studied intensively, there is substantially less understanding with regard to the main products of cement hydration, i.e., C‐S‐H, portlandite, ettringite, etc. In this work a potentiometry based setup was used to study the influence of succinic, tartaric, and citric acid on the nucleation and growth of portlandite and C‐S‐H. We found that the investigated molecules not only lead to a significant delay in nucleation by stabilization of prenucleation clusters, but also show a strong influence on the process of crystal growth. Further the effect of these molecules on the hydration reaction of tricalcium silicate was examined using ex‐situ calorimetry. We found a decent retarding effect on this reaction, even when there was almost no observable effect on the nucleation process in the previous experiments.
Einfluss der Granulometrie von klinkereffizienten Zementen auf die Hydratation
Authors: Wedekind Luise , Ludwig Horst‐Michael , Severins Katrin , Müller Christoph
Published: December 2023

Kurzfassung

Aktuelle Untersuchungen, in einem von der Deutschen Bundesstiftung Umwelt geförderten Projekts, verdeutlichen das Potential von klinkereffizienten Zementen mit Kalkstein, Hüttensand oder Recyclingziegel, wenn diese eine granulometrische Optimierung erfahren. Durch die gezielte mechanische Aufbereitung der Klinkerersatzprodukte Hüttensand, Kalkstein und Ziegel sowie der Klinkerkomponente selbst, werden definierte Feinheiten und Partikelgrößenverteilungen erzeugt. So zeigen die Ergebnisse, dass Zemente mit 50 M.‐% Klinker in Mischungen mit Kalkstein, Hüttensand oder Ziegel trotz ihrer identischen stofflichen Zusammensetzung unterschiedliche Wärmeentwicklungen und Hydratationsgrade bei der Zementhydratation aufweisen, die wiederum Effekte auf die Festigkeitsentwicklungen bewirken. Die Untersuchungen zur Hydratation von klinkereffizienten Zementen ermöglichen die chemisch‐physikalischen Vorgänge für das Erreichen der zulassungsrelevanter Mörtel‐ und Betoneigenschaften zu verstehen und dieses Wissen für weitere granulometrische Optimierungen zu nutzen.
Mechanochemical Activation of the C‐S‐H binder Celitement
Authors: Hinder Daniel , Zimmermann Adrian , Fylak Marc
Published: December 2023

The hydraulic binder Celitement is produced by a mechanochemical activation of an X‐ray amorphous CSH phase. This process step not only chemically activates the material, but also reduces its specific surface area. Thus, both strength and workability of Celitement based systems can be controlled. In this paper the effect of the duration of the activation milling on chemical and microstructural changes of Celitement is focused. Therefore ATR‐FTIR Spectroscopy, Thermogravimetry, Heatflow Calorimetry, Scanning Electron Microscopy and BET (N2) specific surface area measurements are used aside classical experiments on the flow spread and compressive strength of Celitement based mortars. As a result, it is shown that micro structural changes and chemical activation occur already at the beginning of the activation milling and significantly influence the practical performance of mortars.
Zur beschleunigten Verfestigung durch Suspensionsmischprozesse
Authors: Landmann Mirko
Published: December 2023

Kurzfassung

Es konnte aufgezeigt werden, dass bei Suspensionsmischprozessen innerhalb 2‐stufiger Mischverfahren neben einer verbesserten Partikeldispergierung auch eine beschleunigte Ver‐festigung als Begleiteffekt zu beobachten ist. Voraussetzung hierfür ist die Verwendung eines verfahrenstechnisch optimierten Suspensionsmischers, in dem die Suspensionsbestandteile durch eine hohe Arbeitsgeschwindigkeit der Mischwerkzeuge suspendiert werden. In Hinblick der industriellen Anwendung von Suspensionsmischern wurden die wesentlichen system‐, betriebs‐ und betontechnologische Anforderungen systematisiert. Die beschleunigte Verfestigung kann unter anderem auf eine bessere Partikeldispergierung sowie verstärkte Keimbildungsprozesse zurückgeführt werden, wobei nicht alle Ursachen vollständig geklärt werden konnten.
The peculiar behaviour of low‐carbon concretes under salt frost exposure
Authors: Müller Matthias , Ludwig Horst‐Michael , Ehrhardt Dirk , Unbehau Sophie , Kraft Bettina
Published: December 2023

Since the early days of concrete construction, the deterioration of concrete due to the combined action of frost, water and de‐icing salts had been observed. This salt frost attack is typically associated with surface scaling. The underlying mechanism for that damage was unresolved for many decades and many conflicting damage theories exist. In the past, that knowledge gap was primarily of academic interest, as a good salt frost scaling resistance of clinker rich concretes was easily achieved with air entrainment. However, as that approach increasingly reaches its limit for “low‐carbon concretes”, an in‐depth knowledge of the damage mechanisms can help to identify alternative measures to ensure good salt frost scaling resistance of such concretes. Based on a novel theory, which can explain important characteristics of salt frost attack and the generation of scaling damage, an additional cause for the unfavourable influence of clinker reduction on salt frost resistance were identified.
Untersuchungen zur Ladungsmessung als Prüfmethode zur Bestimmung des Chloridwiderstandes von Beton
Authors: Drenkard Hannah , Fischer Christian
Published: December 2023

Kurzfassung

Der Widerstand eines Betons gegen Chlorideindringen ist eine wichtige Kenngröße zur Bewertung seiner Dauerhaftigkeit. Zur Ermittlung dieser Größe wird häufig der sog. Rapid Chloride Migration (RCM) Test angewendet. Daneben gibt es auch Vorschläge für einen Modified Chloride Migration (MCM) Test, bei welchem der Ladungsfluss durch den Probekörper ermittelt wird. Die Ermittlung des Chloridmigrationskoeffizienten erfolgt anschließend über eine Regressionsfunktion, die den Zusammenhang aus der im Versuch gemessenen spezifischen Ladungsflussrate und den Ergebnissen aus RCM‐Tests herstellt. Die Datenlage zu dem Zusammenhang der einzelnen Verfahren muss jedoch noch weiter ausgebaut werden. Bei den hier dargestellten Untersuchungen werden daher für Betone und Mörtel herkömmliche RCM Tests angewendet und zusätzliche Messungen für die Ermittlung des Ladungsflusses sowie des spezifischen Elektrolytwiderstandes ergänzt. Dabei werden u.a. verschiedene Versuchsrandbedingungen wie beispielsweise die Variabilität der Chloridkonzentration im Test‐Setup betrachtet. Die bisherigen Ergebnisse deuten darauf hin, dass bestehende Zusammenhänge zwischen den einzelnen Prüfverfahren in Abhängigkeit gewisser Versuchsrandbedingungen formuliert werden müssen.
Entwicklung verschiedener Baumaterialien auf der Basis der Paludikultur Rohrkolben
Authors: Krus M. , Theuerkorn W. , Großkinsky Th. , Kraft R.
Published: December 2023

Ausgehend vom bereits in mehreren Gebäuden eingesetzten Typhaboard mit seinen zahlreichen umwelttechnischen und bauphysikalischen Vorteilen wurden inzwischen neue Baustoffe auf Basis von Rohrkolben entwickelt. Neben Magnesit als Bindemittel wurden mit Erfolg andere Kleber getestet, die ebenfalls nachhaltig sind und einer Kompostierung nicht im Wege stehen. Selbst unter Verwendung von Lehm können für Einsatzzwecke, die keiner besonderen Feuchtebelastung ausgesetzt sind, stabile und zugleich dämmende Platten hergestellt werden. Als Baustoff‐Neuentwicklung ist zum einen die Entwicklung eines Boards zur Aufdachdämmung zu nennen, das aufgrund einer speziellen Partikelgeometrie und ‐anordnung eine geringere Rohdichte und Wärmeleitfähigkeit besitzt. Des Weiteren wurde eine staubarme Schüttdämmung aus Rohrkolben und eine Art OSB‐Ersatz mit vergleichbaren Festigkeiten entwickelt sowie ein spezieller sehr schlanker Deckenaufbau aus Typha. Die Entwicklung eines hoch tragfähigen Holzersatzes ist ebenfalls in Arbeit.
Thermodynamisch‐analytische Modellierung der Karbonatisierung in Betonen aus klinkerreduzierten Zementen
Authors: Steiner Sarah , Winnefeld Frank , Proske Tilo , Lothenbach Barbara
Published: December 2023

Kurzfassung

Das Bestreben, die Umwelteinwirkungen von Zement und Beton zu verringern, wird zukünftig zum vermehrten Einsatz klinkerreduzierter Zemente führen. Etablierte Modelle zur Vorhersage der Karbonatisierungstiefe (xc) sind aber häufig auf Betone aus handelsüblichem Zement beschränkt. In diesem Beitrag werden die Karbonatisierungsraten von Beton aus Zement mit bis zu 60 Gew.‐% Kalksteinmehl (LS) und w/z‐Werten von 0,3 bis 0,75 untersucht. Zur Abschätzung der xc wurde ein gekoppeltes analytisch‐thermodynamisches Modell entwickelt. Der vorgeschlagene Modellierungsansatz beinhaltet die thermodynamische Berechnung der effektiven CO2‐Bindekapazität und einen analytischen Ansatz zur Abschätzung des CO2‐Diffusionskoeffizienten. Die gute Übereinstimmung zwischen berechneten und experimentell (XRD und TGA) ermittelten Phasenzusammensetzungen zeigt, dass thermodynamische Teilmodelle eine Möglichkeit bieten die Vorhersagegenauigkeit der xc zu verbessern. Die größten Abweichungen zwischen simulierten und tatsächlichen xc wurden bei dichtem Beton beobachtet. Die Untersuchungen und Modellierungen ergaben, dass die betontechnologisch optimierten, klinkerreduzierten Betone mit bis zu 60 Gew.‐% Kalksteinmehl ähnlich hohe Karbonatisierungswiderstände aufweisen können wie Beton aus CEM I 52.5 R.
Cu(II) Promoted C(sp3)−H Activation in Unactivated Cycloalkanes: Oxo‐Alkylation of Styrenes to Synthesize β‐Disubstituted Ketones
Authors: Das Krishna Mohan , Pal Adwitiya , Surya T Lakshmi , Roy Lisa , Thakur Arunabha
Published: December 2023

We report the Cu(II) catalyzed synthesis of β‐disubstituted ketones from styrene via oxo‐alkylation with unactivated cycloalkanes as the alkylating agent in presence of tert‐butylhydroperoxide (TBHP) and 1‐methylimidazole as oxidant and base respectively. β‐disubstituted ketones are known to be synthesized by using either expensive Ru/Ir complexes, or low‐cost metal complexes (e. g., Fe, Mn) with activated species like aldehyde, acid, alcohol, or phthalimide derivatives as the alkylating agent, however, use of unactivated cycloalkanes directly as the alkylating agent remains challenging. A wide range of aliphatic C−H substrates as well as various olefinic arenes and heteroarene (35 substrates including 14 new substrates) are well‐tolerated in this method. Hammett analysis shed more light on the substitution effect in the olefinic part on the overall mechanism. Furthermore, the controlled experiments, kinetic isotope effect study, and theoretical calculations (DFT) enable us to gain deeper insight of mechanistic intricacies of this new simple and atom‐economic methodology.
Interspecific killing of wolverines by one wolf pack
Authors: Young Kiana B. , Saalfeld David T. , Brandt Colette , Smith Kyle R. , Spivey Timothy J. , Stantorf Cory J.
Published: December 2023

Interactions between different species of predators are not uncommon, yet they are generally understudied in North America. Across their range, gray wolves (Canis lupus) and wolverines (Gulo gulo) occupy similar habitats and dietary niches. However, due to the elusiveness and relatively low density of these two species, interactions between them are not well documented. Here, we describe three instances of a single wolf pack killing a wolverine in the span of 13 months. None of the wolverines killed by wolves were consumed, suggesting that food was not the primary motivation behind the killings. Alternatively, defense of a food resource, territoriality, interspecific competitive killing, or some combination of those behaviors appear to be the cause of these actions. Documentation of these occurrences improves our understanding of wolf and wolverine ecology, interspecific predator interactions, and potential future changes to this aspect of community ecology.
Performance Analysis of Triple‐Cation Mixed‐Halide Bifacial Perovskite Solar Cell with 17% Rear and 25% Front Efficiency
Authors: Jaiswal Nilesh , Singh Vivek Pratap , Kumari Dolly , Pandey Saurabh Kumar
Published: December 2023

The goal of bifacial technology is to increase the efficiency of solar cells (SC) by capturing albedo sunlight and converting it to electrical energy. The use of triple‐cation mixed‐halide perovskite solar cells (PSC) has sparked a lot of curiosity and could be the potential for improved power conversion efficiency (PCE) associated with traditional PSCs. Herein, n–i–p‐configured triple‐cation mixed‐halide‐based bifacial PSC is studied using the SC capacitance simulator 1D tool. Through our simulation, the impact of thickness in electron and hole transport layers (ETL and HTLs), defect density, doping density, and the thickness of the light‐harvesting layer on the device performance is examined. With an optimal design, the device exhibits an absolutely staggering efficiency of 25.28% from the front side and around 17.19% from the rear. This cell, due to its high albedo absorption, linearly enhances the short‐circuit current; hence, it overcomes the classical current‐matching limit of ordinary PSCs. The proposed device FTO/TiO2/[Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3]/CuSbS2has a remarkable efficiency that increases linearly with albedo, making it very appealing for new, high‐efficiency solar applications.
Experimental Investigation of the Lithium Calendering Process for Direct Contact Prelithiation of Lithium‐Ion Batteries
Authors: Stumper Benedikt , Dhom Jonas , Schlosser Lukas , Daub Rüdiger
Published: December 2023

Lithium‐ion batteries suffer from high initial capacity losses during formation. One possible approach to compensate for these initial capacity losses is prelithiation, which is the addition of lithium into the battery cell before formation. A promising method is direct contact prelithiation using lithium foil, which requires lithium foil thicknesses below 10 μm to ensure the safe and accurate performance of the prelithiation process. However, free‐standing lithium foils are only commercially available down to a thickness of 20 μm; hence, in this present work, the calendering process of lithium is investigated in detail. An already developed process model will be adapted to provide detailed information on the deformation properties and thickness reduction of different lithium foil thicknesses. A design of experiments is used to investigate the influences of lithium foil geometry, line load, web speed, and roller temperature on the deformation behavior of lithium during calendering. Lithium foil is applied onto anodes by calendering, which are electrochemically investigated using pouch cells. The cells prelithiated by calendering show improved electrochemical performance compared to the manually prelithiated cells, increasing cycle life by 19%.
Improved Localized Laser Doping of Boron‐Doped Si Paste for High‐Efficiency Solar Cells
Authors: Qian Feng , Shen Honglie , Qian Hongqiang , Hong Juan
Published: December 2023

Laser doping (LD) of born‐doped Si paste (Si paste) is a potential boron‐doping approach for advanced solar cells. It is aimed to develop a top‐hat LD instead of a Gaussian LD and a rear‐side polishing process to fabricate P++ local contacts for improved passivated emitter and rear contact (i‐PERC) cells. With the help of vision alignment, LD is conducted on a dashed line pattern of printed Si paste, which decreases the consumption of paste. The variations of boron content in Si paste and the laser pulse energy density can help customize the doping profile. The predicted result of the boron LD profile is a peak dopant density of 2 × 1019 atoms cm−3 and a dopant depth of over 4.0 μm. When higher firing temperature, it can obtain thicker localized back surface field of over 7 μm, since the gradient of the residual Si concentration at the Al/Si interface can suppress the formation of voids. The overall increment in fill factor, short‐circuit current, and open‐circuit voltage enhances the average efficiency by 0.11% for i‐PERC cells and 0.09% for i‐bifacial PERC cells, respectively, due to the improved local contacts.
Evaporation Properties of Water through Floating Porous Structures for Desalination
Authors: Duan Huiling , Fu Xiaoqiang , Wang Yiding
Published: December 2023

The floating porous structure consists of an optical absorption layer, a porous layer, and an insulating layer. Water is pumped through a porous structure to the top absorption surface for evaporation. A numerical model of interfacial evaporation of floating porous structure is established. A multiphysical field coupling model for heat transfer, flow, and mass transfer within porous structures is simulated. The transient temperature response, evaporation flux, and vapor concentration distribution inside the structure are calculated. Effects of porous structure characteristics, such as size and porosity, on evaporation performance are discussed. With the increase of structure radius, the evaporation amount increases gradually, but the evaporation per unit area decreases with the radius. With the increase of the structure height, the evaporation amount and the evaporation flux decrease, but the decrease is relatively small. The porosity of the porous layer ε1 has a significant effect on the evaporation performance. The increase of ε1 is beneficial to the evaporation of water. When ε1 < 0.3, the effect of the porosity of insulation layer ε2 on the evaporation performance can be neglected.
Potential use of cold plasma treatment for disinfection and quality preservation of grape inoculated with Botrytis cinerea
Authors: Khalaj Ali , Ahmadi Ebrahim , Mirzaei Sohiela , Ghaemizadeh Fahiemeh
Published: December 2023

Gray mold caused by Botrytis cinerea is a serious disease of grape (Vitis vinifera) during storage. The aim of this study is to evaluate the effect of atmosphere cold plasma (a novel and nonthermal technology) on inactivation of B. cinerea and preservation of chemical, physical, and mechanical characteristics of grape inoculated with B. cinerea. Herein, different time of cold plasma (0, 10, 20, and 40 s) was firstly considered to be the main factors, besides different storage time (1, 2, 3, 4, and 5 weeks) at 4°C. According to the results, plasma treatment exhibited inhibitory effect on gray mold percentage and microbial load of B. cinerea (log CFU g−1) during postharvest storage. So, in the last week, the gray mold percentage and microbial load in the control were 100% and 3.6 log CFU g−1, and in 40‐s plasma were 4.5% and 2.53 log CFU g−1, respectively. Although the minimum infection and microbial load were observed in 40‐s plasma, better postharvest quality preservation was observed in short‐time cold plasma treatment (≤20 s). Forty‐second plasma caused fruit tissue destruction and negatively decreased mechanical indices (Emod: 0.0028, Fmax = 1.78, and W = 3.18) and weight loss (91.9) in comparison with ≤20‐s plasma, in which mechanical indices (Emod =0.0077, Fmax = 3.6, and W = 10.06) and weight loss (1/1) were higher. The long‐time cold plasma treatment (40 s) had also maximum effects on color changes (10) and surface temperature (2.8°C). Although the highest TSS and TA were observed in 40‐s Plasma, but different time of plasma treatments had no effect on pH. Altogether, these results indicate that the short‐time cold plasma treatment can inactivate B. cinerea on grape berries and preserve crop quality properties.
Calcium administration appears not to benefit acute pancreatitis patients with hypocalcemia
Authors: Yan Tianao , Ma Yifei , Wang Zheng , Lyu Jun , Wu Shuai , Zhang Chun , Wei Wanzhen , Zeng Jiahui , Ma Zhenhua , Xu Kedong
Published: December 2023

Objective

Hypocalcemia occurs commonly among patients with acute pancreatitis (AP) in the intensive care unit (ICU). Calcium therapy could be used to correct hypocalcemia and maintain calcium levels, but its impact on the prognosis has not been demonstrated. Our study aimed to determine whether calcium therapy could benefit the multiple outcomes of AP patients with hypocalcemia.

Methods

We extracted 807 AP patients with hypocalcemia from the Beth Israel Deaconess Medical Center (MIMIC‐IV) database and performed retrospective analyses. The outcomes were in‐hospital, 28 days, ICU mortality, and the length of stay (LOS) in the hospital and ICU. We performed propensity matching (PSM) and inverse probability weighting (IPTW) to balance the baseline differences and conducted multivariate regression to investigate the impact of calcium therapy.

Results

A total of 620 patients (76.8%) received calcium treatment (calcium group) during hospitalization, while 187 patients (non‐calcium group) did not. Patients in the calcium group did not present significant survival differences between groups before and after matching. After including covariates, calcium administration had no association with patients' in‐hospital (HR: 1.03, 95% Cl: 0.47–2.27, p = .942), 28 days and ICU mortality and was significantly associated with prolonged length of stay in the hospital (effect estimate: 6.18, 95% Cl: 3.27–9.09, p < .001) and ICU (effect estimate: 1.72, 95% Cl: 0.24–3.20, p < .001). Calcium therapy could not benefit patients in subgroups with exclusive parenteral infusion, early calcium therapy (<48 h), or various degrees of hypocalcemia.

Conclusion

AP patients with hypocalcemia could not benefit from calcium administration, which has no association with multiple mortality and is significantly associated with prolonged LOS in the hospital and ICU.
Efficiency of different imaging methods in detecting ocular foreign bodies
Authors: Cheng Tongjie , Zhao Hongmei , Chen Qian , Wang Shenjiang , Jiang Chunhui
Published: December 2023

Background

Ocular foreign bodies (OFBs) are a relatively common occurrence in ocular injuries, and a severe risk factor for vision disorders. They are notoriously challenging to identify and localize precisely to allow surgical removal, even with the most recent technological advancements.

Purpose

To compare the efficiency of different imaging methods in detecting and localizing OFBs.

Methods

We conducted a retrospective analysis of the medical records of patients with OFBs, detected by ultrasound biomicroscopy (UBM) and confirmed during surgery. Patients who presented to our medical center between January 2016 and January 2022 and also underwent computed tomography (CT), X ray, and/or ocular B‐scan ultrasonography (B‐scans) were selected.

Results

This study included 134 patients with a history of ocular trauma and OFBs (mean age: 47.25 years, range: 8–78). The mean time interval from injury to UBM examination was 36.31 months (range: 0.2–120 months). Most OFBs were metallic (51.82%) or plant‐based (25.37%); 22.39% of them were located in the sclera, 26.87% in the anterior chamber, and 23.88% in the ciliary body and iris. OFBs ranged in size from 0.10 to 6.67 mm (mean: 1.15 ± 1.10 mm). B‐scans identified OFBs in 37 of the 119 patients examined (31.09%); CT in 52 of 84 patients (61.90%); and radiography in 29 of 50 patients (58.00%). Univariate and multivariate analyses determined that both CT and radiography showed low detection rates for plant‐based versus non‐plant‐based OFBs (CT: p < 0.001; radiography: p = 0.007), small particles (<1.00 mm vs. >1.00 mm; CT: p = 0.001, radiography: p = 0.024), and with eyeball wall locations (vs. intraocular; CT: p < 0.001, radiography: p = 0.021). Similarly, B‐scans were less efficient for plant‐based and eyeball wall‐located OFBs (both p = 0.001), whereas the difference based on dimensions was not significant (p = 0.118).

Conclusions

CT, radiography, and B‐scans showed lower detection rates for plant‐based, small, and eyeball wall‐located OFBs. Our findings strongly suggest that UBM could be a more adequate imaging modality when such OFBs are suspected.
Deep learning‐based conditional inpainting for restoration of artifact‐affected 4D CT images
Authors: Madesta Frederic , Sentker Thilo , Gauer Tobias , Werner René
Published: December 2023

Background

4D CT imaging is an essential component of radiotherapy of thoracic and abdominal tumors. 4D CT images are, however, often affected by artifacts that compromise treatment planning quality and image information reliability.

Purpose

In this work, deep learning (DL)‐based conditional inpainting is proposed to restore anatomically correct image information of artifact‐affected areas.

Methods

The restoration approach consists of a two‐stage process: DL‐based detection of common interpolation (INT) and double structure (DS) artifacts, followed by conditional inpainting applied to the artifact areas. In this context, conditional refers to a guidance of the inpainting process by patient‐specific image data to ensure anatomically reliable results. The study is based on 65 in‐house 4D CT images of lung cancer patients (48 with only slight artifacts, 17 with pronounced artifacts) and two publicly available 4D CT data sets that serve as independent external test sets.

Results

Automated artifact detection revealed a ROC‐AUC of 0.99 for INT and of 0.97 for DS artifacts (in‐house data). The proposed inpainting method decreased the average root mean squared error (RMSE) by 52 % (INT) and 59 % (DS) for the in‐house data. For the external test data sets, the RMSE improvement is similar (50 % and 59 %, respectively). Applied to 4D CT data with pronounced artifacts (not part of the training set), 72 % of the detectable artifacts were removed.

Conclusions

The results highlight the potential of DL‐based inpainting for restoration of artifact‐affected 4D CT data. Compared to recent 4D CT inpainting and restoration approaches, the proposed methodology illustrates the advantages of exploiting patient‐specific prior image information.
Psychological experiences of family caregivers of patients with breast cancer: Protocol for a meta‐synthesis
Authors: Zhang Qingyuan , Chen Jianfei , Fang Kui , Liu Qianqian , Zhang Pan , Bai Jinbing , Zhang Chunhua
Published: December 2023

Aim

The number of breast cancer patients is increasing, but there are insufficient sources of information for their family caregivers. The purpose of this systematic review was to elaborate the psychologically realistic experiences and corresponding needs of family members of patients with breast cancer in the course of their experience in the disease which may provide them with effective, targeted intervention strategies to improve their quality of life.

Design

Protocol for a meta‐synthesis.

Methods

We will search the Chinese databases (i.e., China National Knowledge Infrastructure, VIP Database and Wanfang Database) and the English databases (i.e., PubMed, Embase, Web of Science, the Cochrane Library, CINAHL and PsycINFO). Qualitative studies from the above databases, studying the psychological experiences of family members of patients with breast cancer, will be searched comprehensively. The quality of the study will be evaluated by two reviewers independently using the Joanna Briggs Institute (JBI) critical appraisal tools for qualitative study, and any disagreements will be discussed and judged by the third reviewer. Data will be extracted using JBI standardized data extraction tool. Then, the literature will be compared and analysed, and the raw results summarized using the JBI meta‐aggregation tool. The reliability and credibility of the overall quality of the included studies will be assessed by using the JBI ConQual approach.

Results

N/A.

No Patient or Public Contribution.

PROSPERO registration number

REDACTED.
Plant‐based dietary patterns and genetic susceptibility to obesity in the CARTaGENE cohort
Authors: Masip Guiomar , Attar Atheer , Nielsen Daiva E.
Published: December 2023

Objective

The study's objective was to examine whether adherence to three plant‐based dietary indices (PDIs) mediated or moderated genetic susceptibility to obesity.

Methods

Baseline participants were 7037 adults (57% women, aged 55.6 ± 7.7 years) from the CARTaGENE cohort of Quebec adults. Two polygenic risk scores for BMI (PRS‐BMI), 92 single‐nucleotide polymorphisms and 2 million single‐nucleotide polymorphisms, and three plant‐based scores were calculated (overall, healthy, and unhealthy). Follow‐up participants were 2258 adults with data on obesity outcomes, measured 6 years later. General linear models were used to examine the relationships between PRSs and PDI scores on obesity outcomes. Causal mediation analyses were conducted to assess mediation and interaction models.

Results

The overall‐ and healthy‐PDIs and PRSs were significantly associated with obesity outcomes. Adherence to PDIs did not mediate or moderate genetic susceptibility to obesity. Associations between PRSs and obesity outcomes were partly mediated by meat intake cross‐sectionally and whole grains intake among males both cross‐sectionally and longitudinally. Higher meat intake had a positive association with obesity outcomes, whereas higher whole grains intake had an inverse association.

Conclusions

These findings suggest that components of a plant‐based diet and a shift away from animal products, specifically meat, might be beneficial for nutrition interventions, particularly among individuals with higher genetic risk of obesity.
Effect of ionizing radiation on mechanical and damping properties of phenyl‐vinyl‐methyl‐polysiloxane elastomers cured with platinum
Authors: Esin Zühra Çınar , Şen Murat
Published: December 2023

In this study, phenyl‐vinyl‐methyl‐polysiloxane (PVMQ) elastomers were cured with a Pt catalyst and irradiated with different doses (0–80 kGy) using electron beams. Before irradiation studies, rheological analyses were carried out for the three different Platinum‐A (PtA)/Platinum‐B (PtB) ratios by using a Moving Die Rheometer. End of rheological and mechanical analyses 1/2 PtA/PtB ratio was chosen for irradiation studies. To examine the effect of absorbed dose on the mechanical properties of platinum‐cured PVMQ (Pt‐PVMQ) elastomers, stress–strain behavior, stress relaxation, and energy‐damping behavior at static conditions were investigated by cyclic compression analyses. The effect of absorbed dose on the stiffness, permanent deformation, and crosslink densities of Pt‐PVMQ elastomers was also examined. For the identification of the effect of irradiation on the vibration‐damping properties of Pt‐PVMQ elastomers, dynamic mechanical properties were investigated by using an elastomer testing system, and variation of transmissibility, stiffness, and tan delta values with frequency were examined. As a result of this study, the effect of ionizing radiation on the mechanical and dynamic properties of PVMQ elastomer cured with platinum catalyst has been revealed, and it has been shown that some of these properties can be altered with ionizing radiation. The results obtained in this study also showed that Pt‐PVMQ elastomers have higher damping properties than the damping behavior of Pt‐VMQ elastomers, and these Pt‐PVMQ elastomers can be defined as high damping systems.
Acoustic absorption of3Dprinted glycol‐modified polyethylene terephthalate composites with organically modified montmorillonite and short carbon fibers: Experimentation andANNbased predictive strategy
Authors: Mahesh Vinyas
Published: December 2023

In this article, the acoustic properties of 3D printed glycol‐modified polyethylene terephthalate (PETG) reinforced with organically modified montmorillonite (OMMT) nanoclay/short carbon fiber (SCF) nanocomposites are experimentally investigated using ASTM E1050‐08 standard. To this end, the sound absorption coefficient (SAC) of different PETG composites was calculated with the aid of two microphone impedance tube, working in the frequency range of 50–6300 Hz. The effect of different weight percentages (wt%) of OMMT nanoclay, SCFs, and 3D printing infill density on the acoustic behavior of PETG nanocomposites is studied. The experimental results reveal that higher wt% of OMMT nanoclay and SCFs has a beneficial effect on sound absorption. Further, the trend of variation of SAC is justified with morphological studies. Also, an artificial neural network (ANN) based prediction methodology to predict SAC is developed using the datasets obtained from the experimentation. Levenberg–Marquardt backward propagation algorithm with 20 neurons trains the ANN model. Using the trained ANN model, the acoustic properties of PETG/OMMT/SCF nanocomposites with different operating frequencies, infill density and wt% of reinforcements are predicted with less than 5% average error. This can be beneficial in eliminating the fabrication and experimentation costs incurred while assessing the acoustic properties of the PETG composites.

Highlights

PETG/OMMT nanoclay/SCF composite filaments are fabricated.

Acoustic absorption of 3D printed PETG composites are experimentally studied.

ANN based predictive tool is developed using experimental data.

ANN tool predicts the sound absorption and reduces experimentation cost.

Microstructural studies justify the trend of sound absorption.
Ultrasmall Nanoparticles Bind to Fibrinogen and Impair Normal Clot Formation
Authors: Mina Natasha , Guido Vinicius S. , Lima André F. , Oliva Maria Luiza V. , Sousa Alioscka A.
Published: December 2023

The formation of a proper fibrin clot is essential during blood coagulation, as abnormal clots can predispose individuals to bleeding or thrombosis. Despite these concerns, there is currently limited understanding of the potential adverse effects of engineered nanomaterials on fibrin clot formation. This is surprising, given that fibrinogen is highly concentrated in plasma and has a large surface area, making it prone to unintended interactions with nanomaterials. In this study, the impact of ultrasmall gold nanoparticles (usGNPs) on fibrin clot formation is investigated. UsGNPs have gained significant interest in biomedical applications due to their unique physicochemical properties and favorable behavior in complex biofluids. It is found that the usGNPs interacted with fibrinogen, delayed the onset of clot formation, and became physically trapped within the forming fibrin matrix. Confocal microscopy showed that the usGNPs disrupted the normal architecture of the fibrin clot, resulting in a less dense network structure. This disruption led to larger clot pore sizes and increased clot permeability to liquid. Considering the potential health risks associated with abnormal clot formation, a detailed examination of the clot formation process should be included in the standard safety assessment of usGNPs and other nanomedicines.