NaCl Particles Research Articles

Versatile aerosol concentration enrichment system (VACES) operating as a cloud condensation nuclei (CCN) concentrator: development and laboratory characterization

Abstract. The ability of atmospheric aerosol particles to act as cloud condensation nuclei (CCN) depends on many factors, including particle size, chemical composition and meteorological conditions. To expand our knowledge of CCN, it is essential to understand the factors leading to CCN activation. For this purpose, a versatile aerosol concentrator enrichment system (VACES) has been modified to select CCN at different supersaturations. The VACES enables sampling non-volatile CCN particles without altering their chemical and physical properties. The redesigned VACES enriches CCN particles by first passing the aerosol flow to a new saturator and then to a condenser. The activated particles are concentrated by an inertial virtual impactor and then can be returned to their original size by diffusion drying. For the calibration, the saturator temperature was fixed at 52 ∘C and the condenser temperature range was altered from 5 to 25 ∘C to obtain activation curves for NaCl particles of different sizes. Critical water vapour supersaturations can be calculated using the 50 % cut point of these curves. Calibration results have also shown that CCN concentrations can be enriched by a factor of approx. 17, which is in agreement with the experimentally determined enrichment factor of the original VACES. The advantage of the redesigned VACES over conventional CCN counters (both static and continuous flow instruments) lies in the substantial enrichment of activated CCN, which facilitates further chemical analysis.

Filtration performance and charge degradation during particle loading and reusability of charged PTFE needle felt filters

Electret filter materials have attracted wide attention because of their low pressure drop and high filtration efficiency. Few studies have measured the filtration performance and the charging status of the charged filters during soot particle loading. In this study, the polytetrafluoroethylene (PTFE) needle felt filters were charged by a corona discharge method. The filtration efficiency and surface potential were investigated during the soot particle loading process. The effects of NaCl particles, soot particles and A2 dust on surface potential and filtration efficiency were investigated. The reusability of charged filters and the effect of temperature on surface potential were studied. The results indicated that the initial filtration efficiency of charged PTFE needle felt filters (PNFFs) was greatly improved compared with that of uncharged PNFFs. The attenuation rate of the surface potential at 100 °C was faster than that at room temperature. The surface potential decreased with the start of particle deposition on the filters, correspondingly, the filtration efficiency of the charged PNFFs decreased. The efficiency of charged PNFFs loaded by soot particle decreased first and then increased, with the transition point corresponding to 20 Pa of pressure drop growth. With the same increment of pressure drop, soot particles with higher conductivity caused more efficiency degradation than NaCl particles. The reusability of the charged filters was affected by the effectiveness of dust cake removal and the particle conductivity.

Effect of fractal distribution of the porosity on mechanical properties of Al foams manufactured by infiltration

Mechanical properties of metallic foams are highly dependent on the characteristics of porosity. In the case of foams manufactured using space holder particles (SHPs), parameters such as percentage porosity, pore size and cell wall thickness are directly contingent on the SHP used. In this work, different fractal distributions of SHPs were introduced in order to modify the resulting porosity. An Al–Si–Cu alloy was used as raw material for producing metallic foams by infiltration, while NaCl particles of 2 and 4 mm were used as SHPs, modifying the small-to-large particle ratio and fractal dimensions. Cylindrical foams of 10 cm in height and 5 cm in diameter were obtained by infiltrating the Al alloy into the SHPs. Results showed that the use of fractal distribution allowed to slightly increase the percentage porosity, whereas the most important effect was the decrease in cell wall thickness when fractal dimension increased. Mechanical properties were directly affected by these modifications, decreasing when fractality was induced. Finite element analysis models of the foams were obtained in a combination with discrete element method, in order to simulate their compressive elastic behaviors. Young’s modulus estimations were in excellent agreement with experimental results, validating the effect of fractal inclusion and the importance of the correct model selection.

Influences of fine-grained NaCl particles on performance and denitration efficiency of activated carbon during sintering flue gas purification process.

Alkali metal chlorides emitted from sintering flue gas are easily adsorbed on the surface of activated carbon (AC) in the purification process. In this paper, NaCl particles adsorbing onto AC were simulated by impregnation method, and the size and morphology of NaCl particles were similar to those of NaCl-PM10 emitted from sintering flue gas. With the adsorption of NaCl particles, 2-10-μm pores of AC were filled, and the specific surface area of AC decreased. But NaCl led to the increase of acidic functional groups on the surface of AC. When 0.75 wt% NaCl was adsorbed, it was beneficial for AC catalytic denitration (de-NOx), because the chemical reaction was strengthened by acidic functional groups, so it showed a certain promotion of de-NOx efficiency. As 1.5 wt% NaCl and 3 wt% NaCl were adsorbed, NaCl had an inhibitory effect on AC de-NOx, which was because the specific surface area of AC decreased, and the prevention of physical adsorption played a major role. As a result, the de-NOx efficiency of AC adsorbed with 3 wt% NaCl decreased from 40.59 to 23.02% at 150 °C. Therefore, the absorption of NaCl fine particles on AC should not exceed 0.75 wt%.

Rapid reactive synthesis of TiAl3 intermetallics by thermal explosion and its oxidation resistance at high temperature

Porous TiAl3 intermetallics were synthesized from Ti-75 at.% Al elemental powder mixtures using an energy-saving and rapid reactive method of thermal explosion (TE). The results demonstrated that the actual temperature of the compact climbed rapidly from 673 °C to 1036 °C within 24 s, indicating that an obvious TE reaction occurred during sintering process. The video graphs suggested that the TE in Ti–Al system behaved instant occurrence and overall heating whether from axial or radial direction. The silver wires and NaCl particles that pressed on the surface of the sample disappeared due to the heavy heat released during TE reaction. Only pure TiAl3 phases were synthesized in TE products and the open porosity of 55.4% was easy to obtain. After high-temperature treatment at 1000 °C, large amounts of sintering-neck formed and then improved the compressive strength of porous TiAl3 materials. Moreover, the mass gain curve of porous TiAl3 intermetallics oxidized at 650 °C for 120 h exhibited the parabolic oxidation rate law. XPS analysis confirmed that the strong O 1s peak was 531.4 eV which was the typical binding energy of Al2O3. Therefore, the excellent oxidation resistance of porous TiAl3 foams would be considered as good candidate materials for prolonging the service life at high temperatures.

Humidity effects on the detection of soluble and insoluble nanoparticles in butanol operated condensation particle counters

Abstract. In this study the impact of humidity on heterogeneous nucleation of n-butanol onto hygroscopic and nonabsorbent charged and neutral particles was investigated using a fast expansion chamber and commercial continuous flow type condensation particle counters (CPCs). More specifically, we measured the activation probability of sodium chloride (NaCl) and silver (Ag) nanoparticles by using n-butanol as condensing liquid with the size analyzing nuclei counter (SANC). In addition, the cutoff diameters of regular butanol-based CPCs for both seed materials under different charging states were measured and compared to SANC results. Our findings reveal a strong humidity dependence of NaCl particles in the sub-10 nm size range since the activation of sodium chloride seeds is enhanced with increasing relative humidity. In addition, negatively charged NaCl particles with a diameter below 3.5 nm reveal a charge-enhanced activation. For Ag seeds this humidity and charge dependence was not observed, underlining the importance of molecular interactions between seed and vapor molecules. Consequently, the cutoff diameter of a butanol-based CPC can be reduced significantly by increasing the relative humidity. This finding suggests that cutoff diameters of butanol CPCs under ambient conditions are likely smaller than corresponding cutoff diameters measured under clean (dry) laboratory conditions. At the same time, we caution that the humidity dependence may lead to wrong interpretations if the aerosol composition is not known.

Interfaces of Gas-Aerosol Particles: Relative Humidity and Salt Concentration Effects.

The growth of aerosol particles is intimately related to chemical reactions in the gas phase and particle phase and at gas-aerosol particle interfaces. While chemical reactions in gas and particle phases are well documented, there is very little information regarding interface-related reactions. The interface of gas-aerosol particles not only facilitates a physical channel for organic species to enter and exit but also provides a necessary lane for culturing chemical reactions. The physical and chemical properties of gas-particle interfaces have not been studied extensively, nor have the reactions occurring at the interfaces been well researched. This is mainly due to the fact that there is a lack of suitable in situ interface-sensitive analytical techniques for direct measurements of interfacial properties. The motivation behind this research is to understand how interfaces play a role in the growth of aerosol particles. We have developed in situ interface-specific second harmonic scattering to examine interfacial behaviors of molecules of aerosol particles under different relative humidity (RH) and salt concentrations. Both the relative humidity and salt concentration can change the particle size and the phase of the aerosol. RH not only varies the concentration of solutes inside aerosol particles but also changes interfacial hydration in local regions. Organic molecules were found to exhibit distinct behaviors at the interfaces and bulk on NaCl particles under different RH levels. Our quantitative analyses showed that the interfacial adsorption free energies remain unchanged while interfacial areas increase as the relative humidity increases. Furthermore, the surface tension of NaCl particles decreases as the RH increases. Our experimental findings from the novel nonlinear optical scattering technique stress the importance of interfacial water behaviors on aerosol particles in the atmosphere.

Physicochemical and morphological characterization of atmospheric coarse particles by SEM/EDS in new urban central districts of a megacity.

Physicochemical and morphological characteristics of atmospheric particles in new urban centers of fast-developing megacities are not well understood. In this study, atmospheric coarse particles (PM2.5-10) were simultaneously collected in multiple stations (10) in new urban centers, namely Beylikduzu, Buyukcekmece, and Esenyurt, of Istanbul using a modified passive particulate sampling method. Scanning electron microscope and energy dispersive X-photon spectroscopy (SEM-EDS) was used to investigate the size distribution characteristics, chemical composition and their weight percent abundances, and morphological properties of the collected particles. The particle clusters were mainly dominated by Ca-rich Al silicates, Ca dominant, Ca- and S-rich, and NaCl particles, respectively. Their potential sources were assigned to the natural sources (e.g., wind erosion, soil resuspension, and sea sprays) and anthropogenic activities (construction, transportation, mining and crushing, and cement production). In addition to the major contributions (up to 47% of particle number abundance), the minor contribution clusters (less than 1%) with transitional metals rich particles (Fe, Zn, and Cu rich) mainly from anthropogenic sources (combustion, traffic, and vehicular emissions) were identified. The typical size range (> 0.65 to < 11.00μm) distribution of the major particle clusters fits a left-skewed modal distribution with a peak at 1.10-2.30-μm size range. However, the number of particles decreases significantly with increasing distance to the source, and this justification is stronger for larger size fractions (> 2.3μm). Particle numbers and varieties indicated significant spatial variations depending upon the identified sources, meteorological factors, and temporal conditions. In general, the results of this study suggest that the passive sampling of PM2.5-10 coupled with SEM/EDS based single-particle analysis is an effective tool to understand the physicochemical characterization and spatial and temporal variations of atmospheric particles in urban environments.

Surface Energy of Filtration Media Influencing the Filtration Performance against Solid Particles, Oily Aerosol, and Bacterial Aerosol.

Particulate airborne pollutants are a big concern to public health, and it brings growing attention about effective filtration devices. Especially, particulate matters smaller than 2.5 µm can reach the thoracic region and the blood stream, and the associated health risk can be exacerbated when pathogenic microbials are present in the air. This study aims at understanding the surface characteristics of nonwoven media that influence filtration performance against solid particles (sodium chloride, NaCl), oily aerosol (dioctyl phthalate, DOP), and Staphylococcus aureus (S. aureus) bacteria. Nonwoven media of polystyrene (PS) fibers were fabricated by electrospinning and its pristine surface energy (38.5 mN/m) was modified to decrease (12.3 mN/m) by the plasma enhanced chemical vapor deposition (PECVD) of octafluorocyclobutane (C4F8) or to increase (68.5 mN/m) by the oxygen (O2) plasma treatment. For NaCl particles and S. aureus aerosol, PS electrospun web showed higher quality factor than polypropylene (PP) meltblown electret that is readily available for commercial products. The O2 plasma treatment of PS media significantly deteriorated the filtration efficiency, presumably due to the quick dissipation of static charges by the O2 plasma treatment. The C4F8 treated, fluorinated PS media resisted quick wetting of DOP, and its filtration efficiency for DOP and S. aureus remained similar while its efficiency for NaCl decreased. The findings of this study will impact on determining relevant surface treatments for effective particulate filtration. As this study examined the instantaneous performance within 1–2 min of particulate exposure, and the further study with the extended exposure is suggested.

Biocompatible Polymers for the Synthesis of Nanosalts via Supramolecular Ion-Dipole Interaction.

High salt (NaCl) consumption is critical for many healthy problems, e.g., high blood pressure, heart attack, and stroke. Nanosized NaCl particles hold great promise for reducing salt intake; however, they suffered from deliquescence due to their large surface area. We report a facile yet general strategy for the preparation of NaCl nanoparticles (nanosalts) with controllable sizes and moisture resistance property by using biocompatible polymers, such as polyethylene glycol, polyvinylpyrrolidone, polypropylene glycol, polylactic acid, polycaprolactone, and copoly(oxyethylene/oxypropylene/oxyethylene) via supramolecular ion-dipole interaction. The size can be tuned in a range of 100-160 nm by changing the molecular weight or concentration of polymer ligands. Nanosalts protected by polymers showed faster dissolution rate and better moisture resistance compared with microsized NaCl particles without polymer ligands. This work promotes the future development of nanosalts for food and industrial applications to improve human health.

Formation factors and emission characteristics of ultrafine particulate matters during Na-rich char gasification

In this study, the release and formation characteristics of ultrafine particle matters (PM) during the gasification of Na-rich char are investigated. Two different pre-treatment methods, i.e., water washing and mineral loading, were employed to figure out the effects of various minerals on the deconvolution behaviors of PM, enabling the development of countermeasures. Furthermore, the mineralogical characteristics of the ash resulting from the mineral loading were also discussed. Results showed that a large amount of fine NaCl particles was generated during Na-rich char gasification. Gasification temperature and pressure essentially govern the concentration of Na and Cl species in the gas phase, which determines the quantity and morphology of PM. Specifically, the particle size of PM obtained at 1000 and 1050 °C is mainly distributed in the range of 0.2–0.4 μm. For the W-char gasified at 1100 and 1150 °C, the PM with the size between 0.6 and 1.2 μm is predominant. On the other hand, the particle size of PM decreased remarkably as the gasification pressure increased from 0.1 to 3 MPa. Additionally, due to the low carbon conversion rate of W-char during the CO2 gasification at 1100 °C, over 75% of the total PM were in the size range of 0.2–0.6 μm. The gasification of kaolin loaded W-char generated abundant spherical particles mainly present as alkali and alkaline earth metal aluminosilicates rather than NaCl particles. When it comes to adding diatomite into char, only a few spherical particles, mainly present as aluminosilicates, were detected, indicating the superior performance of diatomite on restraining PM release. The addition of diatomite into W-char could reduce ash fusion temperature, and the agglomerated coarse particles in bottom ash could capture the PM, which inhibited the release of PM to some extent. In contrast, the CaO added in char reacted with the clay and quartz that would otherwise immobilize Na, leading to the more intense release of Na- and Ca-bearing PM.

Cohesive zone method based multi particle finite element simulation of compaction densification process of Al and NaCl laminar composite powders

Multi particle finite element method (MPFEM) has been extensively used to numerically model the compaction process of powder materials. However, MPFEM is not able to simulate the fracture phenomenon for brittle powder materials. In this study, cohesive zone method (CZM) based MPFEM is developed to simulate the compaction densification process of Al and NaCl laminar composite powders. Cohesive zone layer and initial crack are used in modeling the NaCl particle to reproduce its fracture process. A simulation of gravity effect is first conducted to arrange the powders randomly, and then top punch moves downwards to compact the laminar composite powders. Different initial random packing structures, size ratios of NaCl/Al powders and contents of NaCl powders are constructed for compaction with different pressures. Macro and micro analysis of the numerical modeling results is carried out to identify the densification process. Physical experiments and data fitting are used to validate the accuracy and robustness of the numerical simulation. Results demonstrate that the developed CZM-based MPFEM has successfully simulated the fracture phenomenon of NaCl powders and the compaction process of Al and NaCl laminar powders.

Synthesis of open-cell copper foam using friction sintering

A technique for doing solid-state sintering on friction stir welding or milling machines is developed. Heat and pressure needed for sintering are generated using a rotating tool with a flat shoulder. The developed process results in fast heating and cooling rates, sharply reducing sintering time. Sintered parts can be extracted within minutes from end of sintering. The process is cost-effective and can be used to produce large, three-dimensional sintered parts. The technique is used to fabricate open-cell copper foam using sintering and dissolution process with NaCl particles as space holders. Microstructural features of fabricated foam are studied using scanning electron microscopy, microcomputed tomography, and optical microscopy. Its mechanical properties are studied using compression tests. Plateau stress, compressive strength, energy absorption density, and thermal conductivity of obtained foam are on par with those reported in literature for foams obtained using furnace sintering and friction compaction methods. The developed foam has three-scale microstructure and could be used in heat exchanger, sound absorption, catalysis, boiling, and filtration applications.

Porous NbAl3/TiAl3 intermetallic composites with controllable porosity and pore morphology prepared by two-step thermal explosion

Porous NbAl3/TiAl3 with adjustable porosity was prepared by the thermal explosion (TE) mode of combustion synthesis (CS). This was achieved by using NaCl as temporary space holder, which was completely removed from specimens before TE reaction. The combustion image of this process provided the visual evidence for the observation of TE. The temperature profile, course of reaction as well as the effect of NaCl content on the phase composition, pore morphology and open porosity of porous NbAl3/TiAl3 were investigated. The results showed that the addition of TiH2 prevent the samples from cracking and deforming, and in situ synthesis of NbAl3/TiAl3 intermetallic composites. The interconnected channel was formed when using NaCl as space holder, which made the porous NbAl3/TiAl3 an open cellular structure. The open porosity can be improved from 48% to 79% by adding 70vol.% NaCl particles. The small pores (<20μm) in porous NbAl3/TiAl3 originated from the intergranular pores in green compact and the decomposition of TiH2, whereas the large pores (200–300μm) were attributed to the replication of NaCl particles. This leachable space holder route provides a flexible way to adjust the pore morphology and porosity to multifarious applications.

Filtration performance and loading capacity of nano-structured composite filter media for applications with high soot concentrations

The investigation of filtration and loading performance of fibrous filters with different structures is of high importance for designing filters with long lifetime used in applications with high soot concentrations. Penetration of the soot agglomerates and NaCl particles (with the mobility diameters of 50, 80, 100, 200 and 300 nm) through two types of composite filter media (with the nanostructured layer of electrospun nanofibers and PTFE membrane, respectively) was analyzed. Meanwhile, evolution of the experimental and modeled pressure drop during the particles loading process at the velocities of 6.7 and 11.1 cm/s was also studied. The cake thickness was measured by a new and non-contact method utilizing a 3D optical profiler which would not alter the cake structure. The results showed that the soot penetration was lower than that of NaCl particles under the same condition, because the soot agglomerates had larger effective interception length than the NaCl particles with the same mobility diameter. The pressure drop of the filters loaded with soot agglomerates increased faster than that with NaCl particles. Furthermore, the pressure drop increased faster at the velocity of 11.1 cm/s because of formation of more compact cake. In addition, the pressure drop of the filter with a lower solidity nanostructured layer increased slower because more particles could penetrate into its inner part. The model data agreed with the experimental data well in the case of soot loading. Our results indicate that the filters which have relatively low filtration efficiency against the standard compact aerosol particles yet sufficient efficiency against the soot agglomerates and an open structure can be used in the applications with high soot concentrations to gain a long lifetime.

3D bioprinting of alginate scaffolds with controlled micropores by leaching of recrystallized salts

It is well known that three-dimensional scaffolds with controlled macropores and micropores are crucially important for tissue engineering. In the present study, a facile method based on leaching of recrystallized sodium chloride (NaCl) is used to create micropores in 3D printed alginate scaffolds. The macropores with size of 811 ± 78 µm were controlled by 3D printing, and the micropores with size of 3.2 ± 1.4 µm were produced by leaching of the recrystallized NaCl particles. The microporosity can be controlled by the added amount of sodium ions in the alginate inks. The properties of scaffolds including water adsorption, protein delivery and mechanical properties were tailored by the produced micropores. This simple and cell-friendly method might be interesting for 3D bioprinting of tissue engineering scaffolds with designed physical characteristics using alginate-based hydrogel bioinks.

Product characteristics in simultaneous crystallization of NaCl and CaSO4 from aqueous solution under different evaporation rates

Knowledge about simultaneous crystallization in evaporative processes for water reuse is important for the promotion of particles with desirable characteristics. In this work, simultaneous crystallization of sodium chloride and calcium sulfate hemihydrate (HH) from aqueous solutions in unseeded batch mode is addressed. Both the crystallization mechanisms and the resulting particle morphological features have been identified. NaCl particles are generated by heterogeneous primary nucleation in solution, followed by growth and NaCl agglomeration. Calcium sulfate hemihydrate (HH) particles are also formed by heterogeneous primary nucleation in solution followed by crystal growth. HH crystals agglomerate with NaCl in all particle size ranges. Product particles are thus agglomerates with multimodal population densities in submillimetric size ranges, with HH widely dispersed throughout the size span of the particulate product. In comparison with NaCl binary solutions, simultaneous crystallization promotes the formation of larger, less polydisperse NaCl particles. Low supersaturations (low evaporation rates) inhibit HH agglomeration with NaCl. The submillimetric sized particles formed during simultaneous crystallization of NaCl and HH indicate ease in solid-liquid downstream separation.

Computational and Experimental Analysis of Ultrafine Particle Dispersion During Granite Polishing

The granite manufacturing industry is an environment in which workers are exposed to high levels of ultrafine particles (UFPs) and crystalline silica dust. Overexposure to crystalline silica can cause health problems, in particular silicosis. This fatal lung disease persists worldwide despite knowledge of methods to control it. One way to partially overcome the problem of subjectivity and try to achieve objective experimental results is to run field crystalline silica dust surveys with trained human assessors (panelists). Such field inspections allow the determination of ambient air concentrations and are now seen as being a more convenient method for UFP impact assessment in the field. One drawback of field inspections is that they can get rather expensive, especially if the survey is conducted for an extended period of time involving a high number of panelists. This paper reviews the techniques that can be adopted to measure UFPs in the field and discusses how such techniques can be used as an alternative to, or in combination with, gas tracer dispersion methods for UFP impact assessment purposes, and how the results of field UFP measurements and model outputs can be related and compared to each other. Two simulation methods were used to study crystalline silica dust exposure during the granite polishing process (experimental and numerical). This study presents a method to measure UFP dispersion during granite manufacturing processes. A computational model was constructed to simulate the physical problem. The numerical study was carried out, on a simplified configuration (bench), modeling particle distribution near a rotating tool. CFD simulation results were compared to the experimental data using NaCl particles, a tracer gas (CO2), and UFP dispersion from granite polishing. The results showed good agreement between the two methods.

Influence of Porosity on the Elastic Modulus of Ti-Zr-Ta-Nb Foams with a Low Nb Content

The development of titanium foams with a low elastic modulus has increased their scientific and technological relevance due to the evident need to avoid stress shielding problems. In this work, we studied the synthesis and characterization of Ti-13Zr-13Ta-3Nb (wt.%) alloy foams which present high potential for biomedical applications. A Ti-Nb-Ta-Zr mixture was produced by mechanical alloying using a planetary mill. Ti alloy foams were obtained using NaCl as a space-holder (40, 50, and 60 v/v %) that was mixed with the metallic powders and compacted under 420 MPa stress. NaCl particles were removed from the green compacts by submerging samples in distilled water at 60 °C. The green compacts were sintered at 1300 °C for 3 h in Ar atmosphere. Powders and foams were characterized by SEM and optical microscopy. The results showed that Ti-based foams with a tailored heterogeneous pore distribution can be obtained using the space holder method. The elastic modulus (E) of foams was estimated and measured between 5 and 25 GPa using theoretical and finite element analysis (FEA) models which are close to the E values measured experimentally. The results showed that foams with 50% and 60% porosity are potential bone replacement materials because their E value is closer to the E value of human bone.

Impact of particle strength and matrix ductility on the deformation mechanism of metallic syntactic foam

This paper presents a systematic study on the interaction between particle strength, matrix ductility and the deformation mechanism in metallic syntactic foam (MSF). Packed beds of near-spherical NaCl particles (ø2-2.8 mm) were infiltrated with liquid metal to produce the required samples. The brittle zinc alloy ZA-27 and ductile Aluminium (99% Al) were used as matrix materials. NaCl particles were retained inside half of these samples to replicate MSF containing high-strength particles. NaCl was leached from the remaining samples to investigate MSF with weak particles. This procedure ensured that all samples had a near-identical matrix geometry and microstructure, thus isolating the effect of particle strength. Quasi-static compression tests were conducted and significant changes in the deformation behaviour were observed. Samples containing NaCl particles deformed in a shear-band dominated mode, whilst the ductile foam underwent layer-by-layer deformation.