David Mannes

Paul Scherrer Institut | PSI · Research Department "Research with Neutrons and Muons (NUM)"

Archaeological wooden artefacts are commonly found in waterlogged conditions exhibiting a degraded and fragile wood structure. Depending on the degree of degradation, they might collapse and/or shrink during drying processes after excavation, leading to a total loss of the cultural heritage information encoded in the wood structure. Conservation tr...

This paper presents the analysis of the particle-laden liquid metal wake flow around a cylindrical obstacle at different obstacle Reynolds numbers. Particles in liquid metal are visualized using dynamic neutron radiography. We present the results of particle tracking velocimetry of the obstacle wake flow using an improved version of our image proce...

This paper demonstrates particle tracking velocimetry performed for a model system wherein particle-laden liquid metal flow around a cylindrical obstacle was studied. We present the image processing methodology developed for particle detection in images with disparate and often low signal- and contrast-to-noise ratios, and the application of our MH...

This paper reports on the study of two brass objects discovered at the À la Montagne necropolis in Avenches, Switzerland. The first one, a toiletry kit, is a composite object (metal and wood) with a complex design. The second, a capsule bracelet, raises the question of the function of the capsule and its content. Various analyses (scanning electron...

Vapor sorption in hygroscopic porous materials is accompanied by latent heat release/storage, which can influence indoor thermal comfort and building heating and cooling energy consumption. There is a need to better understand the coupled vapor and heat transport during adsorption and desorption. In this study, longitudinal spruce samples are expos...

Der vorliegende Band versammelt Ergebnisse eines vom SNF unterstützten, multidisziplinären Forschungsprojekts zu Korrosion im Innern von historischen Blechblasinstrumenten und ergänzt sie mit weiteren Beiträgen zum Thema der Konservierung insbesondere im Museumsbetrieb. Musikwissenschaftliche und organologische Fragestellungen treffen dabei auf che...

Fast neutron imaging is a nondestructive technique for large-scale objects such as nuclear fuel rods. However, present detectors are based on conventional phosphors (typically microcrystalline ZnS:Cu) that have intrinsic drawbacks, including light scattering, γ-ray sensitivity, and afterglow. Fast neutron imaging with colloidal nanocrystals (NCs) w...

In recent decades, computed tomography (CT) combined with suitable image processing software has become a valuable tool to enable the reading of texts written on scrolls, which are fragile, damaged or fused together, without physically unwrapping them. X-ray based computer tomography has successfully been used on scrolls made of soft materials such...

Sorption of water vapour in hygroscopic porous materials is associated with latent heat release and absorption. This phenomenon should be taken into account to achieve a better understanding of the coupled transfer of vapour and heat in hygroscopic porous materials. In this paper, water vapour adsorption and desorption in the longitudinal direction...

This paper demonstrates particle tracking velocimetry performed for a model system wherein particle-laden liquid metal flow about a cylindrical obstacle was studied. We present the image processing methodology developed for particle detection in images with disparate and often low signal- and contrast-to-noise ratios, and the application of our MHT...

Just after the start into the new millennium the concept for combined neutron and X-ray imaging was introduced by extending the standard configuration of the thermal neutron imaging NEUTRA instrument with a complementary 320 kV X-ray tube setup. Using essentially the same detector configuration for both neutron and X-ray imaging enables a pixel-wis...

We report on the realization of an improved concept for the detection of fast neutrons using a specific setup of scintillators with the aim to overcome limitations in spatial resolution. While fast neutron imaging (FNI) is a technique to investigate very thick material layers in transmission mode, currently there is a limit in the spatial resolutio...

In metallurgical processing, non-metallic inclusions contaminating metallic materials are one highly relevant challenge. Bubble injection into molten metals boosts the inclusion control and removal, thus enhancing metal homogenisation and purification. Although this principle of bubble flotation has been used for a long time, the effects of bubble–...

This chapter explains how to use tomography methods, both with thermal and cold neutrons and also X-rays for the investigation of cultural heritage objects. With the help of these noninvasive techniques, it becomes possible to describe and analyze the whole three-dimensional structure and composition of samples in a size range between a few millime...

Ladle metallurgical treatment affects the chemical composition and impurities in molten steel. To remove non-metallic inclusions, gas injection into the ladle and intense stirring by means of bubble flows are essential in the refining process. This paper reports on a model experiment that provides an insight into the bubble - particle interaction i...

Violin varnishes influence the vibrational properties of tonewood. However, the frequency dependence of the varnish influence and mechanical properties of typical varnishes has received little attention. The viscoelastic properties of various violin varnish materials over the audible frequency range were characterized by dynamic mechanical analysis...

Fast neutrons offer high penetration capabilities for both light and dense materials due to their comparatively low interaction cross sections, making them ideal for imaging of large-scale objects such as large fossils or as-built plane turbines, where X-rays or thermal neutrons do not provide sufficient penetration. However, inefficient fast neutr...

The particular structure of the sublimation front in vacuum freeze-drying of porous media is, in most situations, not accessible at the pore scale. The classical measurement techniques access the process only globally. Knowledge about the structure of the front, however, is necessary for prescriptive analysis of freeze-drying, as it dictates not on...

4D wavelength-resolved neutron tomography of a reference sample made of several polycrystalline materials, namely nickel, iron, titanium, lead, copper and aluminium, is presented. Data were acquired using the time-of-flight transmission imaging method at the IMAT beamline at the ISIS pulsed neutron source. Wavelength-dispersive tomography reconstru...

Violin varnishes are known to alter the longitudinal and radial material properties of violin tonewood. Here, the varnish-induced changes in the vibrational and elastic properties of spruce and maple wood were studied by modal analysis of rectangular plates. This contact-free investigation yields the eigenfrequencies and corresponding mode shapes a...

Two superabsorbent polymer (SAP) samples were studied with respect to their sorption kinetics in freshly prepared cement pastes that were exposed to evaporation. SAP 1 was a self-releasing type material when tested in extracted cement pore solution, whereas SAP 2 was a retentive type. These polymers had proven efficient to mitigate plastic shrinkag...

Violin varnishes are known to affect both moisture absorption and vibrational properties of violin wood. However, traditional multi-layered varnish systems suffer from substantial wear as a result of intensive use, which calls for deeper understanding of the specific impact of individual layers. Using sophisticated in-situ neutron imaging and vibra...

In order to understand the effect of varnishes that act as a barrier to water adsorption by wood – in terms of moisture content – in humid atmospheres, modern maple replica samples have been manufactured by a practicing luthier. They are coated with a variety of recipes thought to have been used in either the original manufacture from the 17th to 1...

Neutron radiography and tomography are imaging techniques with the potential to pioneer drying technology as they can visualize water transport processes during drying, even if the process is fully equipped. While water has a high attenuation coefficient and absorbs most of the radiation, metals and carbon attenuate significantly less neutrons. Thi...

To assess salt damage risks in building materials and geomaterials, the key components to identify are the accumulation of salts and the damage propagation. Experimental data combining both are scarce but offer an additional richness for understanding the coupling between transport and mechanics in the context of salt crystallization in porous medi...

Read it for FREE: https://rdcu.be/brMzD. Violins are varnished to protect them against wear, from changes in relative humidity and to enhance the instrument’s appearance. Furthermore, studies have shown that the application of varnish alters the mechanical and vibrational properties of the wood, respectively, the instrument. Commonly, the varnish...

Chloride ions are an important actor in the corrosion of iron-based archaeological artifact. To stop this degradation, excavated objects are subjected to dechlorination treatment. However, there is no guarantee that this will remove all chloride from the object, as some can be found deep inside the object. To assess the ability of dechlorination tr...

We describe in this paper the experimental procedure, the data treatment and the quantification of the black body correction: an experimental approach to compensate for scattering and systematic biases in quantitative neutron imaging based on experimental data. The correction algorithm is based on two steps; estimation of the scattering component a...

Structural properties of cohesive powders are dominated by its microstructural composition. Powders with a fractal microstructure show particularly interesting properties during compaction where a microstructural transition and a fractal breakdown happen before compaction and force transport. The study of this phenomenon has been challenging due to...

This entry gives an introductory overview of the application of the modern well‐established neutron and X‐ray imaging methods to museum objects and related materials. Since both kinds of radiation complement each other often in their interaction with matter, a combination of the image data can provide the perfect noninvasive picture of inner conten...

In this paper, we describe, why and how neutron imaging methods are applied to contribute to the knowledge about historical music instruments, either brass based or using wood as structural material. Beside the recovery of constructive details of old brass wind instruments with the aim to build equivalent replica, the influence of moisture on inner...

A novel non-destructive space-resolved method for studying binder burnout is presented. Debinding of dry pressed zinc oxide green bodies was analyzed by neutron imaging. Neutrons in contrast to X-rays allow penetrating samples with large dimensions up to 80 mm and at the same time detecting variations in the organics content as small as 0.1 wt%. We...

We propose a method for improving the quantification of neutron imaging measurements with scintillator-camera based detectors by correcting for systematic biases introduced by scattered neutrons and other sources such as light reflections in the detector system. This method is fully experimental, using reference measurements with a grid of small bl...

Staked-in-needle prefilled syringes (SIN-PFS) are widely used for the parenteral administration of drug product solutions. During stability studies, clogging of the injection needle was observed in syringes filled with concentrated antibody solution. A prerequisite for this phenomenon is that liquid has entered the needle. In this study, we charact...

The development of neutron imaging from a qualitative inspection tool towards a quantitative technique in materials science has increased the requirements for accuracy significantly. Quantifying the thickness or the density of polycrystalline samples with high accuracy using neutron imaging has two main problems: (i) the scattering from the sample...

Staked-in needle pre-fillable syringes (SIN-PFS) are a convenient delivery system widely established in the growing pharmaceutical market. Under specific storage conditions, the needle of PFS containing high concentration drug product (DP) solution is prone to clogging, which prevents administration of the liquid. The purpose of this study is to cl...

Non-destructive imaging of the internal structures of pearls has so far been mainly based on X-ray imaging methods. As organic matter is almost transparent to X-rays, the identification of some structures can be difficult. This study shows that neutron imaging can be a helpful complementary method to visualize structures inside pearls beyond standa...

X-ray and neutron imaging depend on different physical processes based on the interaction with matter that results in different characteristics in the output image. X-ray computed tomography (CT) imaging of objects made of low-density materials, like wooden musical instruments, can achieve high quality, while metal objects like brass instruments ar...

Due to the high sensitivity for hydrogen, the detection and quantification of moisture and moisture transport processes are some of the key topics in neutron imaging. Especially when dealing with hygroscopic material, such as wood and other porous media, it is crucial for quantitative analyses to know and control the ambient conditions of the sampl...

Knowing the resolution and effective pixel size of an imaging system is essential for dimensional and quantitative measurements. A collection of test devices was developed for neutron imaging that can be used to quantify pixel and voxel size, resolution of the imaging system, and beam divergence. The first set of devices is intended for measurement...

Within this paper we summarize new approaches for the utilization of neutron beams for imaging purposes. Whereas most of the methods are still based on the radiography mode - however now with higher performance with respect to spatial resolution, dynamic range and linearity (obtained often in short exposure time) - the new aspects of using polarize...

The methodical progress in the field of neutron imaging is visible in general but on different levels in the particular labs. Consequently, the access to most suitable beam ports, the usage of advanced imaging detector systems and the professional image processing made the technique competitive to other non-destructive tools like X-ray imaging. Bas...

Gemmology deals with the characterization of coloured stones, diamonds and pearls used in the jewellery sector. As the investigated objects are in general rather valuable, a large variety of non-destructive testing methods (e.g. X-ray luminescence, X-ray tomography, UV/VIS spectroscopy, etc.) is routinely used for their inspection and characterisat...

Ancient musical instruments are complex objects constructed in the past with the aim of obtaining the best sound quality. Construction parameters change during time according to the aesthetics of the historical period and required sonic/musical features. Musical instruments are mostly made of wood, metals and hide. Neutron based methods such as dif...

The obvious purpose of varnishing a stringed instrument is the protection against wear and relative humidity changes as well as enhancing its aesthetic appearance. Besides, it is known that varnishing changes the acoustic properties of the wood [1]. Unlike studies on the chemical compositions of old varnishes, in searching for the “secret” of well-...

Felsic and mafic gneisses constitute large proportions of the upper and lower continental crust. Gneisses often display high anisotropy of elastic properties associated with preferred orientations of sheet silicates. Here we study the elastic anisotropy of a sample of Tambo gneiss from Promontogno in the Central Alps. We apply optical microscopy, t...

Moisture behaviour of plywood is investigated in combination with detailed structural analysis. In the lab, neutron radiography and X-ray computed tomography (X-ray CT) were used to map the moisture distribution and internal structure of plywood respectively. In an outdoor natural weathering test, the average moisture content (MC) and moisture dist...

A musical instrument is a witness of the many human visual and aural sensibilities, beliefs and dreams. It is not just a technical object, but one with its own aesthetic properties, an object that makes a variety of characteristic sounds without necessarily the existence of a connection between its visual and sound aesthetic. Preserving an instrume...

Moisture is a driving factor in the long-term mechanical deterioration of canvas paintings, as well as for a number of physico–chemical degradation processes. Since the 1990s a number of publications have addressed the equilibrium hygroscopic uptake and the hygro-mechanical deformation of linen canvas, oil paint, animal glue, and ground paint. In o...

Quantitative neutron imaging was applied for the dynamic monitoring of the internal moisture distribution of fruit slices during convective drying in a drying tunnel. The impact of several process conditions was evaluated, including airflow temperature, air speed and incident radiation. This technique also unveiled that anisotropic shrinkage was ca...

Measurement and visualization of water flow in soil and roots is essential for understanding of how roots take up water from soils. Such information would allow for the optimization of irrigation practices and for the identification of the optimal traits for the capture of water, in particular when water is scarce. However, measuring water flow in...

The combined utilization of neutron and X-ray imaging for non-invasive investigations of cultural heritage objects is demonstrated on the example of a short sword found a few years ago in lake Zug, Switzerland. After conservation treatments carried out at the Swiss National Museum the sword was examined at the Paul Scherrer Institut (PSI), Villigen...

The Violinist (1920), the only sculpture made by Gargallo using lead sheet and wood, is being corroded by carbonation, most probably due to the organic vapours released by the wood inside, a material not chemically compatible with lead. Hydrogen plasma has been tested and proved to be an effective treatment meaning that the sculpture has to be dism...

Der Heißpressvorgang ist der zentrale Abschnitt der Holzwerkstoffherstellung – kapazitäts- und produkteigenschaftsbestimmend zugleich. Viele Wechselwirkungen innerhalb der verdichteten Partikelmatte basieren auf Modellvorstellungen und diskreten Messungen einzelner Parameter. Die dieWärmeübertragung dominierende Wasserdampfbewegung ist für Prozesso...

Gas generation as a result of electrolyte decomposition is one of the major issues of high-performance rechargeable batteries. Here, we report the direct observation of gassing in operating lithium-ion batteries using neutron imaging. This technique can be used to obtain qualitative as well as quantitative information by applying a new analysis app...

Water penetration in porous building materials can cause damage in building components exposed to wet environmental conditions. A system to monitor water penetration by means of electrical conductivity measurements is presented (Gummerson et al. Build Environ 15:101–108, 1980). The sensor allows non-destructive and continuous monitoring of differen...

Wood-based composites are industrially produced panels made of resin-blended wood furnish material consolidated by hot pressing. Precise knowledge of the physical interrelations, such as heat and mass transfer induced densification and curing, are inevitable to control process performance and final product properties. Neutron radiography is able to...

The diffusion of water into spruce wood coated with an acrylate/polyurethane and with a silica-based coating system is investigated by varying the humidity conditions. Thereby, the change of moisture content (MC) is measured and analysed with the non-destructive method of neutron imaging. For the acrylate/polyurethane based coating system, the barr...

Es wurden vier kommerziell erhältliche Beschichtungssysteme bestehend aus Grundierung und Deckschicht für den Fassaden‐ und Fensterbereich auf Fichtenholzproben appliziert. Bei diesen Systemen wurden in der Grundierung bzw. in der Deckschicht folgende Bindemittel eingesetzt: Alkydharze, Acrylate, Hybridsysteme, modifizierte PU‐Systeme, Co‐Polymere...