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In the optimisation of processing parameters for additive manufactured parts using, e.g. selective laser melting (SLM) or electron beam melting, the measurement of the part densities is essential and of high interest. However, there is no common standard. Different institutes and system providers are using their own principles and guidelines. This study investigates the accuracies of the three measurement principles: Archimedes method, microscopic analysis of cross sections and X‐ray scanning.

A total of 15 test samples on five density levels (densities between 90 and 99.5 per cent) were produced using the SLM process. The samples are analysed regarding the accuracy of the measurement principles and their reproducibility taking into account influencing parameters like the buoyancy of a sample in air (Archimedes method) or different magnifications of a cross section.

The Archimedes method shows a very high accuracy (±0.08 per cent for high densities) and repeatability (±<0.1 per cent) on all density levels. In contrast to the Archimedes method, taking a micrograph of a specific cross section allows to influence the resulting density and the coefficient of variation reaches values>4 per cent. However, for low porosities, mean densities are comparable to the results of the Archimedes method even though calculated densities are typically somewhat too high. The advantage of the image guided analysis (2D and 3D) is getting more information about the distribution, size and form of pores in the part.

The findings do not only refer to metallic parts but generally to all parts having a specific porosity. The study is a contribution to the American Society for Testing and Materials initiative F42 “Additive Manufacturing Technology” and especially to the subcommittee “test methods”.

The purpose of this paper is to optimize and improve a bipolar charge transport (BCT) model used to simulate charge dynamics in insulating polymer materials, specifically low-density polyethylene (LDPE).

An optimization algorithm is applied to optimize the BCT model by comparing the model outputs with experimental data obtained using two kinds of measurements: space charge distribution using the pulsed electroacoustic (PEA) method and current measurements in nonstationary conditions.

The study provides an optimal set of parameters that offers a good correlation between model outputs and several experiments conducted under varying applied fields. The study evaluates the quantity of charges remaining inside the dielectric even after 24 h of short circuit. Moreover, the effects of increasing the electric field on charge trapping and detrapping rates are addressed.

This study only examined experiments with different applied electric fields, and thus the obtained parameters may not suit the experimental outputs if the experimental temperature varies. Further improvement may be achieved by introducing additional experiments or another source of measurements.

This work provides a unique set of optimal parameters that best match both current and charge density measurements for a BCT model in LDPE and demonstrates the use of trust region reflective algorithm for parameter optimization. The study also attempts to evaluate the equations used to describe charge trapping and detrapping phenomena, providing a deeper understanding of the physics behind the model.

The purpose of this paper is to describe a new apparatus for testing acoustic insulating, air permeating and water vapor transfer properties of fibrous assemblies with density variation.

An apparatus is designed and built in order to investigate the acoustic insulating, air permeating and water vapor transfer properties of fiber assemblies with density variation. The apparatus mainly consists of three chambers, just like the structure of a syringe. The three properties can be measured by placing different sensors at the corresponding chambers. The material density variation can be realized by compression.

The new apparatus can realize the measurement of the three properties with density variation, which provides a new perspective to study the physical property of fibrous assemblies.

The paper introduces a new apparatus for testing acoustic insulating, air permeating and water vapor transfer properties of fibrous assemblies with density variation.

The purpose of this paper is to investigate the effect of remelting each layer on the homogeneity of nickel-titanium (NiTi) parts fabricated from elemental nickel and titanium powders using laser powder bed fusion (LPBF). In addition, the influence of manufacturing parameters and different melting strategies, including multiple cycles of remelting, on printability and macro defects, such as pore and crack formation, have been investigated.

An LPBF process was used to manufacture NiTi alloy from elementally blended powders and was evaluated with the use of a remelting scanning strategy to improve the homogeneity of fabricated specimens. Furthermore, both single melt and up to two remeltings were used.

The results indicate that remelting can be beneficial for density improvement as well as chemical and phase composition homogenization. Backscattered electron mode in scanning electron microscope showed a reduction in the presence of unmixed Ni and Ti elemental powders in response to increasing the number of remelts. The microhardness values of NiTi parts for the different numbers of melts studied were similar and ranged from 487 to 495 HV. Nevertheless, it was observed that measurement error decreases as the number of remelts increases, suggesting an increase in chemical and phase composition homogeneity. However, X-ray diffraction analysis revealed the presence of multiple phases regardless of the number of melt runs.

For the first time, to the best of the authors’ knowledge, elementally blended NiTi powders were fabricated via LPBF using remelting scanning strategies.

The paper aims to throw light on the interactions taking place between the different chemical compositions at various temperatures. P-methylacetophenone is a polar dissolvable, which is positively related by dipole–dipole co-operations and is exceptionally compelling a direct result of the shortfall of any critical primary impacts because of the absence of hydrogen bonds; hence, it might work an enormous dipole moment (μ = 3.62 D). Alcohols additionally assume a significant part in industries and research facilities as reagents and pull in incredible consideration as helpful solvents in the green innovation. They are utilized as pressure-driven liquids in drugs, beauty care products, aromas, paints removers, flavors, dye stuffs and as a germ-free specialist.

Mixtures were prepared by mass in airtight ground stopper bottles. The mass measurements were performed on a digital electronic balance (Mettler Toledo AB135, Switzerland) with an uncertainty of ±0.0001 g. The uncertainty in mole fraction was thus estimated to be less than ±0.0001. The densities of pure liquids and their mixtures were determined using a density meter (DDH-2911, Rudolph Research Analytical). The instrument was calibrated frequently using deionized doubly distilled water and dry air. The estimated uncertainty associated with density measurements is ±0.0003 g.cm⁻³. Viscosities of the pure liquids and their mixtures were determined by using Ostwald’s viscometer. The viscometer was calibrated at each required temperature using doubly distilled water. The viscometer was cleaned, dried and is filled with the sample liquid in a bulb having capacity of 10 ml. The viscometer was then kept in a transparent walled water bath with a thermal stability of ±0.01K for about 20 min to obtain thermal equilibrium. An electronic digital stop watch with an uncertainty of ±0.01 s was used for the flow time measurements for each sample at least four readings were taken and then the average of these was taken.

Negative values of excess molar volume, excess isentropic compressibility and positive values of deviation in viscosity including excess Gibbs energy of activation of viscous flow at different temperatures (303.15, 308.15 and 313.15 K) may be attribution to the specific intermolecular interactions through the hetero-association interaction between the components of the mixtures, resulting in the formation of associated complexes through hydrogen bond interactions.

The excess molar volume (V^E) values were analyzed with the Prigogine–Flory–Patterson theory, which demonstrated that the free volume contribution is the one of the factors influencing negative values of excess molar quantities. The Jouyban–Acree model was used to correlate the experimental values of density, speed of sound and viscosity.

Shows how observations (1993‐1999) and on‐site and laboratory measurements (1993‐1996) have made it possible to define certain prevalent parameters concerning AC corrosion risks. These are from the evaluation and prevention of AC corrosion risks as practised by Gaz de France.

The purpose of Part I of this paper is to investigate the influence of Bi additions on the surface tension, the interfacial tension, and the density of SnZn7Bi alloys (Bi=1 and 3 percent by mass) as a continuation of similar previous studies on Bi and Sb additions to the binary Sn‐Zn alloy. The main aim of Part I is to indicate that the lowering of the surface tension and interfacial tension is not sufficient for practical applications. However, knowledge of the interfacial tension between the soldering flux and the solder is necessary to convert the wetting force into the contact angle. This will be documented in Part II.

The maximum bubble method was applied for the surface tension and the Miyazaki method was applied for the surface tension and the interfacial tension, using the density values from the dilatometric technique. The experimental surface tension results are compared with the Butler's thermodynamic modeling results and are discussed by means of the analysis of variance (ANOVA).

On the basis of previous studies on Sn‐Zn‐Bi‐Sb alloys, the addition of Bi to SnZn7 slightly decreased the surface tension measured in an Ar+H₂ atmosphere, similarly to the Butler's modeling results. Also, a similar slight decrease of the surface tension from the Miyazaki method measured in air and in nitrogen was observed, as well as a more significant lowering of the interfacial tension with the use of a flux in nitrogen. There was also a slight influence of the temperature on the numerical values of the surface tensions and the interfacial tension. In the ANOVA, taking into account the Bi content, the temperature of measurements, the atmosphere and the flux, the flux used was shown as the most important, and also, to a lesser extent, the atmosphere.

It is intended (the purpose of Part II of this paper) to verify the positive influence of Bi additions in SnZn7 alloys on the surface tensions and the interfacial tensions via the contact angles from the interaction with Cu on printed circuit board with different lead‐free finishes.

It is suggested that further studies on more efficient fluxes are necessary for the practical application being in agreement with the ANOVA and the literature information.

A slight improvement of the wettability with the use of Bi additions in the SnZn7Bi alloys in the course of various experimental techniques is proven, similar to results reported in various references. The obtained results will enlarge the SURDAT database of lead‐free soldering materials.

The purpose of this paper is to compare different powder metallurgy (PM) processes to produce ceramic parts through additive manufacturing (AM). This creates the potential to rapidly shape ceramic parts with an almost unlimited shape freedom. In this paper, alumina (Al₂O₃) parts are produced, as Al₂O₃ is currently the most commonly used ceramic material for technical applications.

Variants of the following PM route, with indirect selective laser sintering (indirect SLS) as the AM shaping step, are explored to produce ceramic parts: powder synthesis, indirect SLS, binder removal and furnace sintering and alternative densification steps.

Freeform-shaped Al₂O₃ parts with densities up to approximately 90 per cent are obtained.

The resulting Al₂O₃ parts contain inter-agglomerate pores. To produce higher-quality ceramic parts through indirect SLS, these pores should be avoided or eliminated.

The research is innovative in many ways. First, composite powders are produced using different powder production methods, such as temperature-induced phase separation and dispersion polymerization. Second, four different binder materials are investigated: polyamide (nylon-12), polystyrene, polypropylene and a carnauba wax – low-density polyethylene combination. Further, to produce ceramic parts with increased density, the following densification techniques are investigated as additional steps of the PM process: laser remelting, isostatic pressing and infiltration.

The use of alternative oils for the lubrication of automobile engines has a potential of ecological and technical advantages. It requires the detailed knowledge of several thermophysical and viscosimetric properties in a large temperature range.

For 11 different oils, the density, the heat capacity, the thermal conductivity, the viscosity at ambient pressure and the pressure‐viscosity at maximal 1,000 bar have been measured. The latter has been measured with a newly developed apparatus which is described in detail. Two hydrocarbon‐based factory‐fill oils and nine alternative oils have been tested. Five of the alternative oils are based partly or completely on esters, the other four on polyglycols, one of them additionally on water.

Data for thermophysical and viscosimetric properties are given in form of diagrams and tables. The consequences for the cooling capacity and the film forming behavior are discussed. The latter is only slightly better for the factory‐fill oils, compared to the alternative oils.

The pressure‐viscosity is measured at up to 1,000 bar, which is lower than the maximum pressure in the tribological contacts of an engine.

The published data can be used to calculate tribological contacts which are lubricated with alternative engine oils or with actually used factory‐fill oils. This might help to decide if esters or polyglycols are superior as engine oils.

The results of this test program might be helpful for engineers who are interested in using alternative lubricants in tribosystems.

The purpose of this paper is to demonstrate the processability of cohesive PE-HD particles in laser beam melting processes (LBM) of polymers. Furthermore, we present a characterization method for polymer particles, which can predict the quality of the powder deposition via LBM processes.

This study focuses on the application of dry particle coating processes to increase flowability and bulk density of PE-HD particles. Both has been measured and afterwards validated via powder deposition of PE-HD particles in a LBM machine.

For efficient coating in a dry particle coating process, the PE-HD particles and the attached nanoparticles need to show similar surface chemistry, i.e. both need to behave either hydrophobic or hydrophilic. It is demonstrated that dry particle coating is appropriate to enhance flowability and bulk density of PE-HD particles and hence considerably improves LBM processes and the resulting product quality.

At present, in LBM processes mainly polyamide (PA), 12 particles are used, which are so far quite expensive in comparison to, for example, PE-HD particles. This work provides a unique and versatile method for nanoparticulate surface modification which may be applied to a wide variety of materials. After the coating, the particles are applicable for the LBM process. Our results provide a correlation between flowability and bulk density and the resulting product quality.