cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
title: Improving a 3D Concrete Printing Factory Using Stochastic Modelling for Decision-Support
Creators: name: Walzer, Alexander
name: Kozlova, Mariia
name: Mohite, Ashish
name: Yeomans, Julian
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: probability distribution
subject: global sensitivity analysis
subject: industrial economics
subject: 62

description: Digital Concrete 2024 - Supplementary Proceedings
title: Developing a Computer Vision Application for Crack Detection
Creators: name: Bier, H.
name: Hidding, A.
name: Lewandowska, J.
name: Calabrese, G.
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: computer vision
subject: crack detection
subject: 3D concrete printing
subject: extraterrestrial habitat
subject: YOLOv7
subject: 62

description: The paper addresses a critical issue in 3D concrete printing (3DCP), which is the detection of crack formation during and after the printing process. This problem is significant because cracks in concrete structures can compromise their integrity and needs to be addressed as part of a 3DCP approach implemented at TU Delft for the development of extraterrestrial habitats. Despite the importance of detecting cracks in 3DCP, there is a lack of specific datasets for training computer vision models to perform this task accurately. Previous efforts in this area have been limited, with most existing solutions focusing on traditional casting methods rather than the challenges presented by 3DCP. This paper presents a solution that leverages Computer Vision (CV) techniques, by retraining the YOLOv7 Object Detection (OD) model using a dataset of cracks in regular cast concrete. This approach acknowledges the absence of a substantial 3DCP-specific dataset and adapts existing models to address the problem. By utilizing CV, the proposed method demonstrates similar performance in precision, recall, and mean average precision between the two models YOLOv7 and YOLOv7 tiny. However, the challenges encountered during crack detection in 3DCP samples highlight the need for an expanded and annotated dataset tailored to this specific application. The paper aims to provide a comprehensive overview of the problem, the challenges faced, and the proposed solution. By retraining the YOLOv7 model and discussing the advantages and challenges of CV, the paper contributes to advancing the field of crack prevention in 3DCP. Ultimately, the goal is to improve the quality and safety of 3D-printed concrete structures by enabling timely detection and mitigation of crack formation.
description: Digital Concrete 2024 - Supplementary Proceedings
War Diary of 1st Battalion Canadian Scottish Regiment, Vol. 62 - Appendix 02
Creators: name: Canada. Canadian Army. Canadian Scottish Regiment (Princess Mary's)
Publisher: name: University of Victoria Libraries
Year: 2020
Subjects: subject: Canada. Canadian Army. Canadian Scottish Regiment (Princess Mary's)
subject: War diaries
valueUri: http://id.worldcat.org/fast/1745536
subject: World War (1939-1945)
valueUri: http://id.worldcat.org/fast/1180924
subject: Canada. Canadian Army
valueUri: http://id.worldcat.org/fast/531187

description: This appendix consists of a document titled "Notes on the Building of FD Works" which is a translated pamphlet issued by the First Para Army (Engineers Branch) and based on the experiences of 2 Para Corps, it is reproduced as being the most recent official description of German policy in regard to defensive positions.
[C.3.57.a.] Vive la vie, la joie et l’amour
Creators: name: Delmas, Georges (Dit Georges Isabelli)
Publisher: name: École des Hautes Études en Sciences Sociales; La Voix des Nôtres
Year: 2023
Subjects: http://www.idref.fr/034703926/id
http://www.idref.fr/028473779/id
http://www.idref.fr/027261468/id
http://www.idref.fr/028135350/id
http://www.idref.fr/027257592/id

Abstract
GraphPrints: Towards a Graph Analytic Method for Network Anomaly Detection
Creators: name: Harshaw, Christopher R.
name: Bridges, Robert A.
name: Iannacone, Michael D.
name: Reed, Joel W.
name: Goodall, John R.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Cryptography and Security (cs.CR)
subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: This paper introduces a novel graph-analytic approach for detecting anomalies in network flow data called GraphPrints. Building on foundational network-mining techniques, our method represents time slices of traffic as a graph, then counts graphlets -- small induced subgraphs that describe local topology. By performing outlier detection on the sequence of graphlet counts, anomalous intervals of traffic are identified, and furthermore, individual IPs experiencing abnormal behavior are singled-out. Initial testing of GraphPrints is performed on real network data with an implanted anomaly. Evaluation shows false positive rates bounded by 2.84% at the time-interval level, and 0.05% at the IP-level with 100% true positive rates at both.
description: 4 pages submitted to Cyber & Information Security Research Conference 2016, ACM
title: Investigations on Multi-Sensor Data for Monitoring Volume Flow During the Printing Process
Creators: name: Schönsee, Eric
name: Jeyifous, Olubunmi
name: Strangfeld, Christoph
name: Hüsken, Götz
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: additive manufacturing
subject: in-line monitoring
subject: volume flow
subject: process control
subject: 62

description: Extrusion based 3D concrete printing (3DCP) is a growing technology because of its high potential for automating construction and the new possibilities of design. In conventional construction methods, a sample is taken to be representative for one material batch. However, in 3DCP continuous mixing is used which results in variations during the mixing process. Therefore, one sample is not representative for the entire structure. This leads to the necessity of continuous and real-time process monitoring. This study focuses on the variations of pressure and temperature which are caused by changes in the material due to the ongoing mixing process. Changes in material, which is transported downstream, are influencing sensor signals in different positions with a time delay. In the following, the data is analysed to investigate if the changing material and the so caused change in pressure can be used to calculate volume flow.
description: Digital Concrete 2024 - Supplementary Proceedings
[C.3.58.a.] Allons au-devant de la vie
Creators: name: Delmas, Georges (Dit Georges Isabelli)
Publisher: name: École des Hautes Études en Sciences Sociales; La Voix des Nôtres
Year: 2023
Subjects: http://www.idref.fr/028135350/id
http://www.idref.fr/028473779/id
http://www.idref.fr/027257592/id
http://www.idref.fr/027261468/id
http://www.idref.fr/034703926/id

Abstract
title: Optimization of Fast Penetration Tests for Rheology Control in 3D Printing Concrete
Creators: name: Caneda-Martínez, L.
name: Hassan, M.
name: Demont, L.
name: Keita, E.
name: Belin, P.
name: de Bono, V.
name: Mesnil, R.
name: Caron, J.
name: Roussel, N.
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: fast penetration test
subject: rheology
subject: pocket vane
subject: yield stress
subject: quality control
subject: 62

description: 3D printing concrete must meet demanding requirements in terms of its rheology, which also needs to evolve to adapt to each stage of the printing process. As a result, a thorough control of the rheology during printing is essential for its success. However, the rheological characteristics of 3D-printed con-crete (particularly its yield stress) differ significantly from those displayed by conventional ones. Thus, conventional laboratory tools are generally not suitable for the measurement range required by 3D-printed concretes. Also, for a test method to be applicable for the monitoring of 3D printing, extra requirements must be met, such as being fast, simple and with little sample preparation. This work presents the use of fast penetration tests as a simple method for in situ control of the yield stress of 3D-printed concrete. The study is initially focused on the identification of parameters that may affect the robustness and repeatability of the test for various penetration probe geometries. For this purpose, several tests were carried out on non-aging pure plastic materials (i.e. clays) using penetration probes of different geometries and sizes and varying the test conditions (penetration speed, user and sample shape). The results indicate that the robustness and dispersion of the results are closely related to the geometry of the penetration probe. In that sense, probe geometries that minimize the user dependence and present an adequate size compared to the sample and aggregate size provided optimal results. The clays were tested by additional methods (squeeze test and pocket vane) to obtain equivalence between penetration forces and yield stress. Finally, the method feasibility was tested on 3D printed samples and compared with the results obtained by pocket vane tests.
description: Digital Concrete 2024 - Supplementary Proceedings
Electronic and ionic conductivities in superionic Li$_4$C$_{60}$
Creators: name: Quintavalle, D.
name: Márkus, B. G.
name: Jánossy, A.
name: Simon, F.
name: Klupp, G.
name: Győri, M. A.
name: Kamarás, K.
name: Magnani, G.
name: Pontiroli, D.
name: Riccò, M.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: The $10$ GHz microwave conductivity, $σ(T)$ and high field, $222$ GHz electron spin resonance (HF-ESR) of Li$_4$C$_{60}$ fulleride is measured in a wide temperature range. We suggest that the majority of ESR active sites and at least some of the charge carriers for $σ(T)$ are electrons bound to a small concentration of surplus or vacancy ions in the polymer phase. Both $σ(T)$ and the ESR line shape depend on ionic motion. A change of the activation energy of $σ(T)$ at $125$ K coincides with the onset of the ionic DC conductivity. The ESR line shape is determined mainly by Li ionic motion within octahedral voids below $150$ K. At higher temperatures, fluctuations due to ionic diffusion change the environment of defects from axial to effectively isotropic on the ESR time scale. $σ(T)$ data up to $700$ K through the depolymerization transition confirm that the monomeric phase of Li$_4$C$_{60}$ is a metal.
Ubiquity of density slope oscillations in the central regions of galaxy and cluster-sized systems
Creators: name: Young, Anthony M.
name: Williams, Liliya L. R.
name: Hjorth, Jens
Publisher: name: arXiv
Year: 2016
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: One usually thinks of a radial density profile as having a monotonically changing logarithmic slope, such as in NFW or Einasto profiles. However, in two different classes of commonly used systems, this is often not the case. These classes exhibit non-monotonic changes in their density profile slopes which we call oscillations for short. We analyze these two unrelated classes separately. Class 1 consists of systems that have density oscillations and that are defined through their distribution function $f(E)$, or differential energy distribution $N(E)$, such as isothermal spheres, King profiles, or DARKexp, a theoretically derived model for relaxed collisionless systems. Systems defined through $f(E)$ or $N(E)$ generally have density slope oscillations. Class 1 system oscillations can be found at small, intermediate, or large radii but we focus on a limited set of Class 1 systems that have oscillations in the central regions, usually at $\log(r/r_{-2})\lesssim -2$, where $r_{-2}$ is the largest radius where $d\log(ρ)/d\log(r)=-2$. We show that the shape of their $N(E)$ can roughly predict the amplitude of oscillations. Class 2 systems which are a product of dynamical evolution, consist of observed and simulated galaxies and clusters, and pure dark matter halos. Oscillations in the density profile slope seem pervasive in the central regions of Class 2 systems. We argue that in these systems, slope oscillations are an indication that a system is not fully relaxed. We show that these oscillations can be reproduced by small modifications to $N(E)$ of DARKexp. These affect a small fraction of systems' mass and are confined to $\log(r/r_{-2})\lesssim 0$. The size of these modifications serves as a potential diagnostic for quantifying how far a system is from being relaxed.
description: accepted by the Journal of Cosmology and Astroparticle Physics (JCAP)
3D printing of gas jet nozzles for laser-plasma accelerators
Creators: name: Döpp, A.
name: Guillaume, E.
name: Thaury, C.
name: Gautier, J.
name: Phuoc, K. Ta
name: Malka, V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: Accelerator Physics (physics.acc-ph)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: Recent results on laser wakefield acceleration in tailored plasma channels have underlined the importance of controlling the density profile of the gas target. In particular it was reported that appropriate density tailoring can result in improved injection, acceleration and collimation of laser-accelerated electron beams. To achieve such profiles innovative target designs are required. For this purpose we have reviewed the usage of additive layer manufacturing, commonly known as 3D printing, in order to produce gas jet nozzles. Notably we have compared the performance of two industry standard techniques, namely selective laser sintering (SLS) and stereolithography (SLA). Furthermore we have used the common fused deposition modeling (FDM) to reproduce basic gas jet designs and used SLA and SLS for more sophisticated nozzle designs. The nozzles are characterized interferometrically and used for electron acceleration experiments with the Salle Jaune terawatt laser at Laboratoire d'Optique Appliquée.
title: Case Study on the Use of Thermographic Analysis to Evaluate an Additively Constructed Building
Creators: name: Diggs-McGee, Brandy
name: Kreiger, Megan
name: Kreiger, Eric
name: Negron-McFarlane, Christian
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: additive construction
subject: cement hydration
subject: thermal imaging
subject: thermography
subject: building inspection
subject: 62

description: The use of thermography as a non-destructive testing (NDT) method has been used in literature on conventionally built structures but has limited studies for the layered effect and infill patterns used in additive construction. Thermography was used to evaluate the thermodynamic properties and structural performance during construction of a barracks hut constructed using additive construction at Camp Atterbury, Indiana, US. Thermographic analysis in this case study focused on two aspects: hydration process and structural anomalies. First, thermographic analysis was conducted to monitor the hydration process of cementitious materials used in additive construction. Second, thermal mass principles were used to detect structural anomalies, such as, voids and delamination within the printed structure. The sensitivity of thermographic methods to temperature variations caused by inconsistencies in the structure were able to identify potential weak spots that could compromise the integrity of the building. This case study provides an assessment on the use of non-destructive evaluation for monitoring cement hydration and quality control of structures built by additive construction methods.
description: Digital Concrete 2024 - Supplementary Proceedings
Minimax Design and Order Estimation of FIR Filters for Extending the Bandwidth of ADCs
Creators: name: Wang, Yinan
name: Johansson, Hakan
name: Xu, Hui
name: Diao, Jietao
Publisher: name: arXiv
Year: 2016
Subjects: subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: The bandwidth of the sampling systems, especially for time-interleaved analog-to-digital converters, needs to be extended along with the rapid increase of the sampling rate. A digitally assisted technique becomes a feasible approach to extend the analog bandwidth, as it is impractical to implement the extension in analog circuits. This paper derives accurate order estimation formulas for the bandwidth extension filter, which is designed in the minimax sense with the ripple constraints as the design criteria. The derived filter order estimation is significant in evaluating the computational complexity from the viewpoint of the top-level system design. Moreover, with the proposed order estimates, one can conveniently obtain the minimal order that satisfies the given ripple constraints, which contributes to reducing the design time. Both the performance of the extension filter and its order estimation are illustrated and demonstrated through simulation examples.
description: 4 pages, 3 figures, IEEE Int. Symp. Circuits Syst. (to appear), Montreal, Canada, 2016
title: Non-destructive evaluation for the unbonded interlayer of 3D printed concrete
Creators: name: Bang, Jin
name: Yim, Hong
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: 3D concrete printing
subject: electrical resistivity measurement
subject: unbonded interlayer
subject: flexural strength
subject: 62

description: 3D concrete printing has been widely adopted for fabricating structures without formwork owing to its benefits with an automatic construction and reducing construction waste. To fabricate optimized products, control of the printing process is essential, including the precise management of mechanical components and the use of high-quality materials. Various non-destructive evaluation can be employed to control the deposited filaments and produce high-quality products. This study aims to evaluate the unbonded interlayer between 3D printed concrete layers using electrical resistivity measurement before concrete hardening. The Wenner and square arrays based on the four-electrodes method were designed to assess the unbonded interlayer as soon as concrete layers are printed. A rectangular shape of layered samples with dimensions of 320 mm x 320 mm x 200 mm (ten-layers) are additively manufactured by the 3D printing system. Three different interlayer conditions between fifth and sixth layers is considered to evaluate the defective interlayers using electrical resistivity measurements. The measured electrical resistivity of sample’s length shows that the increased unbonded area between interlayers results in the increased electrical resistivity. The unbonded interlayer is strongly associated with on reduced flexural strength. This finding can represent that evaluating printed layers using electrical resistivity measurements is necessary to obtain high-quality products. The efficient manufacturing consumption time or structural stable, may be decreased to evaluate the defect of the interlayer at the early age concrete before its hardening state.
description: Digital Concrete 2024 - Supplementary Proceedings
Spectroscopic characterization of HD 95086 b with the Gemini Planet Imager
Creators: name: De Rosa, Robert J.
name: Rameau, Julien
name: Patience, Jenny
name: Graham, James R.
name: Doyon, René
name: Lafrenière, David
name: Macintosh, Bruce
name: Pueyo, Laurent
name: Rajan, Abhijith
name: Wang, Jason J.
name: Ward-Duong, Kimberly
name: Hung, Li-Wei
name: Maire, Jérôme
name: Nielsen, Eric L.
name: Ammons, S. Mark
name: Bulger, Joanna
name: Cardwell, Andrew
name: Chilcote, Jeffrey K.
name: Galvez, Ramon L.
name: Gerard, Benjamin L.
name: Goodsell, Stephen
name: Hartung, Markus
name: Hibon, Pascale
name: Ingraham, Patrick
name: Johnson-Groh, Mara
name: Kalas, Paul
name: Konopacky, Quinn M.
name: Marchis, Franck
name: Marois, Christian
name: Metchev, Stanimir
name: Morzinski, Katie M.
name: Oppenheimer, Rebecca
name: Perrin, Marshall D.
name: Rantakyrö, Fredrik T.
name: Savransky, Dmitry
name: Thomas, Sandrine
Publisher: name: arXiv
Year: 2016
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: We present new $H$ (1.5-1.8 $μ$m) photometric and $K_1$ (1.9-2.2 $μ$m) spectroscopic observations of the young exoplanet HD 95086 b obtained with the Gemini Planet Imager. The $H$-band magnitude has been significantly improved relative to previous measurements, whereas the low resolution $K_1$ ($λ/δλ\approx 66$) spectrum is featureless within the measurement uncertainties, and presents a monotonically increasing pseudo-continuum consistent with a cloudy atmosphere. By combining these new measurements with literature $L^{\prime}$ photometry, we compare the spectral energy distribution of the planet to other young planetary-mass companions, field brown dwarfs, and to the predictions of grids of model atmospheres. HD 95086 b is over a magnitude redder in $K_1-L^{\prime}$ color than 2MASS J12073346-3932539 b and HR 8799 c and d, despite having a similar $L^{\prime}$ magnitude. Considering only the near-infrared measurements, HD 95086 b is most analogous to the brown dwarfs 2MASS J2244316+204343 and 2MASS J21481633+4003594, both of which are thought to have dusty atmospheres. Morphologically, the spectral energy distribution of HD 95086 b is best fit by low temperature ($T_{\rm eff} =$ 800-1300 K), low surface gravity spectra from models which simulate high photospheric dust content. This range of effective temperatures is consistent with field L/T transition objects, but the spectral type of HD 95086 b is poorly constrained between early L and late T due to its unusual position the color-magnitude diagram, demonstrating the difficulty in spectral typing young, low surface gravity substellar objects. As one of the reddest such objects, HD 95086 b represents an important empirical benchmark against which our current understanding of the atmospheric properties of young extrasolar planets can be tested.
description: 20 pages, 12 figures, accepted for publication in ApJ
title: Characterization of 3D Concrete Printed Horizontal Structures through Early-Age Deformation Analysis
Creators: name: Szögi, Tamás
name: Kapitány, Kristóf
name: Sólyom, Sándor
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: finite element simulation
subject: inverse material characterization
subject: DIC
subject: 3D concrete printing
subject: 62

description: Current limitations of 3D concrete printing primarily stem from the early-age mechanical properties of the material used. Beyond spatial geometry and printing speed, the characteristic parameters evolving in time such as Young’s modulus and cohesion exert a predominant impact on the stability of freshly printed elements. This study employs time-dependent finite element simulations using ABAQUS software to quantify early-age deformations of concrete printed elements. The primary objective is to anticipate material failure during printing and to optimize the material performance by precisely defining the required properties for desired geometries. The subsequent quantitative analysis of deformations was carried out using Digital Image Correlation (DIC), enabling a comparison between numerical and experimental results. Various printed elements with diverse geometries were scrutinized for validation purposes. This tracing methodological approach was developed to adapt the printing process to site conditions, enhancing inverse material characterization and quality control. Deformations were investigated through parametrically designed horizontal structure elements utilizing the Grasshopper module in Rhino software. The models were designed to be printed without supporting formwork at some point as displacements are particularly significant in such cases. The feasibility of printing at large overhangs promises broader application for 3D printing technology in concrete construction, especially in realizing unique structural shapes.
description: Digital Concrete 2024 - Supplementary Proceedings
title: Improvement of Rheological Properties and Printability of Sodium-Carbonate Activated Slag-Based Systems
Creators: name: Ertuğrul, Onur
name: Özen, Ömer
name: Oktay, Didem
name: Yazar, Tugrul
name: Akturk, Busra
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: one-part alkali-activated materials
subject: sodium-carbonate
subject: reactive MgO
subject: rheology
subject: 3D printing
subject: 62

description: This study investigates the rheological properties and 3D printability of one-part sodium carbonate-activated slag-based mixes for potential use in 3D printing applications. Using sodium carbonate as an activator and substituting reactive MgO with slag, various paste mixtures were formulated. Results indicate that increasing r-MgO substitution raises yield stress while reducing plastic viscosity. Printability and buildability improved with r-MgO substitution instead of slag. A reference mix produced with only slag fails in buildability, but a 10% r-MgO substitution enables the production of ten-layered cylinders. The optimal ratio for improved rheological properties and 3D printability is identified as 10% r-MgO by weight, highlighting the potential enhancement of printability and buildability in these mixes for layer-by-layer 3D printing construction.
description: Digital Concrete 2024 - Supplementary Proceedings
Post-quench dynamics and pre-thermalization in a resonant Bose gas
Creators: name: Yin, Xiao
name: Radzihovsky, Leo
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We explore the dynamics of a resonant Bose gas following its quench to a strongly interacting regime near a Feshbach resonance. For such deep quenches, we utilize a self-consistent dynamic field approximation and find that after an initial regime of many-body Rabi-like oscillations between the condensate and finite-momentum quasiparticle pairs, at long times, the gas reaches a pre-thermalized nonequilibrium steady state. We explore the resulting state through its broad stationary momentum distribution function, that exhibits a power-law high momentum tail. We study the dynamics and steady-state form of the associated enhanced depletion, quench-rate dependent excitation energy, Tan's contact, structure function and radio frequency spectroscopy. We find these predictions to be in a qualitative agreement with recent experiments.
description: 34 pages, 25 figures
title: 3D Printing Architectural Applications of cement-lime mortars with microencapsulated Phase Change Materials (PCM)
Creators: name: Márquez, Álvaro
name: Ramallo, Laura
name: Varela, Hugo
name: Barluenga, Gonzalo
name: Puentes, Javier
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: 3D printing
subject: digital fabrication
subject: lime cement mortars
subject: PCM
subject: prototype
subject: 62

description: 3D printing technology arouses great interest for its application in architecture on facades and building enclosures that still need to be explored. An experimental study of 3D printing laboratory prototypes using low-carbon cement-lime mortars with microencapsulated Phase Change Material (PCM) was carried out to evaluate its application for adaptative building enclosures. Rheology, extrudability and buildability of PCM cement-lime mortars were assessed. Cellulose fibers and rheology modifiers, as sepiolite nano-clay, were used to enhance mortar properties. Rheological parameters were measured using a Dynamic Shear Rheometer (DSR) and Cone Penetration Test (CPT) in fresh state. Fresh compressive strength evolution was assessed by fresh compressive strength test (Squeeze Test) and Early Age monitoring was carried out to keep track of cement hydration and structural build up progress. Extrudability and buildability of mixtures were evaluated by means of RAM Extrusion Test and laboratory 3D printing prototype. This approach provided new knowledge on the design of high thermal performance mortars using digital fabrication in architectural applications, contributing to the digitalization and sustainability of construction and building practice.
description: Digital Concrete 2024 - Supplementary Proceedings
The Accretion Disk Wind in the Black Hole GRS 1915+105
Creators: name: Miller, J. M.
name: Raymond, J.
name: Fabian, A. C.
name: Gallo, E.
name: Kaastra, J.
name: Kallman, T.
name: King, A. L.
name: Proga, D.
name: Reynolds, C. S.
name: Zoghbi, A.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We report on a 120 ks Chandra/HETG spectrum of the black hole GRS 1915+105. The observation was made during an extended and bright soft state in June, 2015. An extremely rich disk wind absorption spectrum is detected, similar to that observed at lower sensitivity in 2007. The very high resolution of the third-order spectrum reveals four components to the disk wind in the Fe K band alone; the fastest has a blue-shift of v = 0.03c. Broadened re-emission from the wind is also detected in the first-order spectrum, giving rise to clear accretion disk P Cygni profiles. Dynamical modeling of the re-emission spectrum gives wind launching radii of r ~ 10^(2-4) GM/c^2. Wind density values of n ~ 10^(13-16) cm^-3 are then required by the ionization parameter formalism. The small launching radii, high density values, and inferred high mass outflow rates signal a role for magnetic driving. With simple, reasonable assumptions, the wind properties constrain the magnitude of the emergent magnetic field to B ~ 10^(3-4) Gauss if the wind is driven via magnetohydrodynamic (MHD) pressure from within the disk, and B ~ 10^(4-5) Gauss if the wind is driven by magnetocentrifugal acceleration. The MHD estimates are below upper limits predicted by the canonical alpha-disk model (Shakura & Sunyaev 1973). We discuss these results in terms of fundamental disk physics and black hole accretion modes.
description: Accepted for publication in ApJ Letters
title: Numerical Simulation of 3D Concrete Printing: From the Layer- to the Structural-Scale
Creators: name: Daadouch, Koussay
name: Reinold, Janis
name: Meschke, Günther
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: 3D concrete printing
subject: PFEM
subject: elasto-viscoplasticity
subject: multiplicative split
subject: buildability prediction
subject: 62

description: Digital Concrete 2024 - Supplementary Proceedings
Preliminary study of 10Be/7Be in rainwater from Xi'an by Accelerator Mass Spectrometry
Creators: name: Zhang, Li
name: Fu, Yun-Chong
Publisher: name: arXiv
Year: 2016
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: The 10Be/7Be ratio is a sensitive tracer for the study of atmospheric transport, particularly with regard to stratosphere-troposphere exchange. Measurements with high accuracy and efficiency are crucial to 7Be and 10Be tracer studies. This article describes sample preparation procedures and analytical benchmarks for 7Be and 10Be measurements at the Xian Accelerator Mass Spectrometry (Xian-AMS) laboratory for the study of rainwater samples. We describe a sample preparation procedure to fabricate beryllium oxide (BeO) AMS targets that includes co-precipitation, anion exchange column separation and purification. We then provide details for the AMS measurement of 7Be and 10Be following the sequence BeO- -> Be2+ -> Be4+ in the Xian- AMS. The 10Be/7Be ratio of rainwater collected in Xian is shown to be about 1.3 at the time of rainfall. The virtue of the method described here is that both 7Be and 10Be are measured in the same sample, and is suitable for routine analysis of large numbers of rainwater samples by AMS.
Gap plasmon resonator arrays for unidirectional launching and shaping of surface plasmon polaritons
Creators: name: Lei, Zeyu
name: Yang, Tian
Publisher: name: arXiv
Year: 2015
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We report the design and experimental realization of a kind of miniaturized devices for efficient unidirectional launching and shaping of surface plasmon polaritons (SPPs). Each device consists of an array of evenly spaced gap plasmon resonators with varying dimensions. Particle swarm optimization is used to achieve a theoretical two dimensional launching efficiency of about 51%, under the normal illumination of a 5-μm waist Gaussian beam at 780 nm. By modifying the wavefront of the SPPs, unidirectional SPPs with focused, Bessel and Airy profiles are launched and imaged with leakage radiation microscopy.
description: 8 pages, 3 figures
title: Open time and extrudability performance analysis of 3D printed concrete with recycled concrete fine aggregates using rheological and computer vision techniques
Creators: name: Haripan, Vislavath
name: Senthilnathan, Shanmugaraj
name: Gettu, Ravindra
name: Santhanam, Manu
name: Raphael, Benny
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: concrete 3D printing
subject: recycled concrete fine aggregates (RCFA)
subject: computer vision
subject: extrudability
subject: open time
subject: 62

description: This study examines the open time and extrudability performance of 3D-printed concrete elements using recycled concrete fine aggregates (RCFA). It emphasizes the importance of fresh state properties like extrudability and open time, which are crucial for the quality of 3D-printed structures. The study introduces a novel methodology that uses conventional rheological tests and computer vision techniques to assess these properties. The rheometer tests give the understanding of the evolution of material stiffness before the printing process and the computer vision technique gives an understanding of temporal extrudability changes during the printing process. The results from both studies show a similar trend in the evolution of material stiffness, signifying the importance of combined test results in analyzing the 3D-printing concrete.
description: Digital Concrete 2024 - Supplementary Proceedings
title: Determination of Optimal Flowability of 3D Printing Concrete Based on Multi-objective Optimization Method
Creators: name: Song, Xinlei
name: Sun, Xiaoyan
name: Wang, Hailong
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: flowability
subject: 3D printing
subject: extrudability
subject: buildability
subject: thixotropy
subject: multi-objective optimization
subject: 62

description: Flowability is a crucial factor affecting the performance of 3D printing concrete. Based on flowability test results, materials suitable for 3D printing can be quickly screened, making it essential to determine the appropriate flowability to optimize the performance of 3D printing concrete. This study maintains constant water-cement ratio, sand ratio, and particle gradation, and adjusts the content of superplasticizer to control the flowability of the concrete mixture. Several performance tests were conducted to analyze the variations in extrudability, buildability, and thixotropy of 3D printing concrete with changing flow-ability. Different evaluation factors are established to quantify the optimal and poor range of extrudability, buildability, and thixotropy. Based on these factors, multi-objective optimization was performed using NSGA(Non-dominated Sorting Genetic Algorithms)-II coupled with the AHP(Analytic Hierarchy Process)-Entropy method to determine the flowability range that ensures good performance. The results show that flowability significantly influences the performance of 3D printing concrete. When the flowability is maintained at 170-180mm, it ensures smooth extrusion and successful printing, meeting the requirements of extrudability, buildability, and thixotropy to the greatest extent. This study provides theoretical basis and practical guidance for the material design and performance optimization of 3D printing concrete.
description: Digital Concrete 2024 - Supplementary Proceedings
title: Extended rheological characterization as a tool for low-binder 3D-printing compositions
Creators: name: de Oliveira Romano, Roberto
name: Nunes de Lima, Francisco
name: Sales de Mesquita, José
name: Pan, Eduardo
name: Pileggi, Rafael
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: 3D printing
subject: low-cement compositions
subject: extended rheological approach
subject: mix-design
subject: sustainability
subject: 62

description: Implementing 3D-printing technology of cementitious compositions holds a significant contribution for revolutionizing the construction sector. However, the current stage of the technology often requires a higher amount of binder compared to conventional concretes, posing environmental challenges during the production of the components. So, as well as a trend in the cement industry, the development of low-binder 3D-printing compositions is an essential step for the sustainability of this process. To this strategy be successfully achieved, the impact of raw material proportioning must be studied on printing properties. Another relevant piece of information is that the development of printable compositions must be carried out in parallel with the choice of printing equipment, adapting its rheological properties to the characteristics of the printer. In this research we developed compositions with low-binder content to be used in a 1k 3D-printer, applying an extended rheological approach to understand the printability requirements. The work was started using a reference composition indicated by the equipment manufacturer, to obtain rheological information of practical interest, creating a list of parameters and behaviors for adequate printability. The development of low-binder compositions was carried out considering the concepts of packing of particles, and our target was a consumption below 290 kg/m³ of cement, the lowest reported in the literature so far for dense components. The rheological properties were investigated applying the methods of rotational rheometry, squeeze flow, Benbow and Bridgwater and flow table. With the results, was possible to highlight the significant rheological contributions at each step in the development of 3D printed compositions, improve sustainability and achieve high-quality printed structures with lower cement consumption than previously reported in the literature.
description: Digital Concrete 2024 - Supplementary Proceedings
title: Development of set-on-demand 3D printable limestone-calcined clay-based cementitious materials using desalination brine
Creators: name: Chen, Yu
name: Zhang, Yamei
name: Schlangen, Erik
name: Çopuroğlu, Oğuzhan
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: set-on-demand printing
subject: LC3
subject: desalination brine
subject: sustainability
subject: low carbon binder
subject: 62

description: The discharge of desalination brine, characterized by an exceptionally high chloride salt concentration, into marine or surface water bodies poses significant threats to aquatic ecosystems. Utilizing desalination in concrete without steel reinforcement emerges as a potential sustainable solution. This study introduces an innovative approach to address these challenges, proposing the development of limestone-calcined clay-based cementitious (LC3) materials accelerated by desalination brine within an inline static mixer-based 3D concrete printing (3DCP) setup. Additionally, the effect of brine on the fresh properties and early-age hydration was also investigated.
description: Digital Concrete 2024 - Supplementary Proceedings
title: Rheological Modifiers in Optimizing Quick Nozzle Mixing Technology for 3D Concrete Printing
Creators: name: Zhang, Nan
name: Sanjayan, Jay
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: 3D concrete printing
subject: nozzle mixing
subject: mixing efficiency
subject: rheological modifiers
subject: 62

description: Quickly mixing concrete at or near the printing nozzle is a new technique developed by the authors to improve 3D concrete printing technology. Quick nozzle mixing (QNM) solves the inherent problem in 3D concrete printing due to the opposing rheological demands for buildability and pumpability. 3D printing requires the concrete to be pumpable, which requires the concrete to be flowable without segregation, while the same concrete should be buildable once printed, which requires the concrete to be stiff and not flowable. The same concrete cannot satisfy both demands. Transporting the concrete to dry materials and mixing the dry materials will not only solve this problem but also allow the printing process to be stopped anytime and start again when needed without having to clean all the equipment (pump, hoses, etc.). The main issue with mixing at the nozzle is that the duration allowed for mixing is relatively short, depending on the nozzle's print speed and the mixer size. To accomplish this technique, the quality improvement of concrete experiencing a short mix (less than 70 s) was studied. The effects of rheological modifiers on the mixing process of concrete were investigated. Results show that the mixing duration can be shortened by increasing the mixing intensity and optimizing raw materials. Furthermore, the type of rheological modifiers can significantly influence the mixing power.
description: Digital Concrete 2024 - Supplementary Proceedings
Malahide College’s Case study: Assessing Quality Research Use
Creators: name: Gleeson, Jo
name: Cutler, Blake
name: Hall, Genevieve
name: Rickinson, Mark
name: Walsh, Lucas
Publisher: name: Monash University
Year: 2023
Subjects: classificationCode: 390305
subject: Professional education and training
classificationCode: 390307
subject: Teacher education and professional development of educators
classificationCode: 390403
subject: Educational administration, management and leadership

description: This practitioner case study shares the story of how Marcus and the Whole School Frameworks Team at Malahide College are using the QURE Assessment Tool to support their plans for quality research use in their school.This case study was developed by the Monash Q Project (2019-2023) and is designed for teachers, school leaders and education system actors who are using research in their work and are looking to use research evidence to support their practice.
title: Comparison of Rotational Rheometers for Ready-Mix Concrete
Creators: name: Muthukrishnan, Shravan
name: Feys, Dimitri
name: Mikhalev, Daniil
name: Baumert, Christian
name: Kluwe, Moritz
name: Link, Julian
name: Mezhov, Alexander
name: Nicia, David
name: Pirharati, Mahmoud
name: Reissig, Silvia
name: Vogel, Christian
name: Haist, Michael
name: Mechtcherine, Viktor
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: 3D concrete printing
subject: rotational rheometers
subject: shearing protocols
subject: ready mix concrete (RMC)
subject: yield stress
subject: plastic viscosity
subject: 62

description: Digital Concrete 2024 - Supplementary Proceedings
title: Comparison between yield stress measurements for fiber-reinforced 3D concrete printing
Creators: name: Zat, Tuani
name: Schmitt Duarte, Ester
name: Webber, Jaine
name: de Matos, Paulo
name: Rodríguez, Erich
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: rheology
subject: yield stress
subject: 3D concrete printing
subject: fiber-reinforced concrete
subject: fiber-reinforced 3DCP
subject: 62

description: Advancements achieved in the field of 3D concrete printing (3DCP) have required a more detailed understanding of its rheological behavior during the manufacturing process. Development and validation of new control techniques are essential to enable the extensive use of 3DCP. Yield stress of concrete is quite important in the 3D printing process as it is directly linked to the buildability performance, as well as it is also related to its structural integrity over time. Incorporation of microfibers is a popular strategy to enhance the mechanical performance of the material, reducing autogenous shrinkage, and, thus affecting its rheological properties. This study assessed the yield stress of fiber-reinforced 3DCP through rotational rheometry, slug tests, and buildability tests. Additionally, flow tests were performed. Concrete mixtures with different types (rock and steel) and percentages (0%, 0.5%, and 1.0%) of microfibers were evaluated. Results demonstrated an increase in the material’s yield stress proportional to the increase in fiber content. When comparing the two types of fiber, rock wool had a greater impact on the yield stress due to its higher surface adhesion compared to steel wool.
description: Digital Concrete 2024 - Supplementary Proceedings
Polarization dependence of nonlinear wave mixing of spinor polaritons in semiconductor microcavities
Creators: name: Lewandowski, Przemyslaw
name: Lafont, Ombline
name: Baudin, Emmanuel
name: Chan, Chris K. P.
name: Leung, P. T.
name: Luk, Samuel M. H.
name: Galopin, Elisabeth
name: Lemaitre, Aristide
name: Bloch, Jacqueline
name: Tignon, Jerome
name: Roussignol, Philippe
name: Kwong, N. H.
name: Binder, Rolf
name: Schumacher, Stefan
Publisher: name: arXiv
Year: 2015
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: The pseudo-spin dynamics of propagating exciton-polaritons in semiconductor microcavities are known to be strongly influenced by TE-TM splitting. As a vivid consequence, in the Rayleigh scattering regime, the TE-TM splitting gives rise to the optical spin Hall effect (OSHE). Much less is known about its role in the nonlinear optical regime in which four-wave mixing for example allows the formation of spatial patterns in the polariton density, such that hexagons and two-spot patterns are observable in the far field. Here we present a detailed analysis of spin-dependent four-wave mixing processes, by combining the (linear) physics of TE-TM splitting with spin-dependent nonlinear processes, i.e., exciton-exciton interaction and fermionic phase-space filling. Our combined theoretical and experimental study elucidates the complex physics of the four-wave mixing processes that govern polarization and orientation of off-axis modes.
title: How Can Nanocellulose Contribute to Enhance the Performance of Concrete 3D Printing?
Creators: name: Aouichat, Belkis
name: Hosseinpoor, Masoud
name: Yahia, Ammar
name: Dupuis, Mario
Publisher: name: Universitätsbibliothek Braunschweig
Year: 2024
Subjects: subject: rheology
subject: digital fabrication
subject: concrete 3D printing
subject: cellulose nanocrystals
subject: cellulose nanofibers
subject: 62

description: Concrete 3D Printing (C3DP), an emerging construction technique using extrusion, promises shorter construction periods, reduced waste, and CO2 emissions, and fosters more ecologically friendly construction practices. However, from a materials perspective, C3DP presents several challenges, particularly in balancing workability and rigidification, which significantly affect its mechanical performance. Enhancement in print material buildup can be achieved using viscosity-enhancing admixtures or fillers. At the nanoscale, cellulose nanocrystals (CNC) and cellulose nanofibers (CNF) have recently been used to improve the rheology, mechanical performance, and durability of concrete. In this study, various cement pastes mixtures were formulated, incorporating two different types of gel suspensions of CNMs at dosages of 0.03%, 0.065%, and 0.20% by mass of cement. The CNMs used included two gel suspensions of CNC and CNF at dosages of 6.43% and 3.0% (by mass), respectively, in water. The visco-elastoplastic properties and stability of the investigated mixtures were evaluated in the fresh state. Moreover, the mechanical performance of the paste mixtures was assessed through flexural and compressive strength testing. The results demonstrated a beneficial effect of applying these CNMs in concrete for 3D printing, improving printability and build-up properties, while ensuring the targeted structural performance of a C3D printed object.
description: Digital Concrete 2024 - Supplementary Proceedings