Inert Gas Stream Research Articles

Mathematical Modeling of Cryochemical Formation of Medicinal Substances in Nanoforms. The Role of Temperature and Dimensional Parameters

The work is aimed at creating a mathematical model of cryochemical synthesis of nanoforms of pharmaceutical substances. The therapeutic efficacy of pharmaceutical substances largely depends on the size and morphology of the particles. Reducing the particle size of pharmaceutical substances to nanoscale makes it possible to obtain highly effective drugs, which makes it possible to use smaller doses of drugs and, thus, reduce side effects and toxicity. Cryochemical synthesis is one of the most powerful methods for obtaining nanoforms of medicament. The method, which is completely new, is based on sublimation or evaporation of the initial pharmaceutical substance under high vacuum conditions and the introduction of the resulting vapors into an inert gas stream, followed by low-temperature condensation of the flow of molecules of the substance from the gas phase on the cooled surface. The first step in the mathematical modeling of cryochemical synthesis processes is the calculation of the temperature field in the carrier gas flow interacting with the cooled surface. For this purpose, a stationary equation of thermal conductivity with mass transfer is used for the one-dimensional case. We prove existence and uniqueness theorems of the solution. Analytical solutions of the equation for Dirichlet, Neumann and Robin boundary conditions are found.

Adsorptive processes for the recovery of VCM emissions using an environmentally friendly MIL-100(Fe) MOF

This work focuses on developing adsorptive separation processes for recovering vinyl chloride emissions from poly(vinyl chloride) production plants. Taking advantage of the mesoporous structure of the MIL-100(Fe) MOF adsorbent, a pressure-swing adsorption separation system was successfully developed for a separation previously dominated by temperature-swing processes. The performance of the PSA unit was compared to an MT-TPSA cycle using the same material and other adsorptive systems found in the literature. The proposed PSA unit can produce an inert gas stream fit for open-air release and a high purity VCM stream capable of being recycled back into the polymerization process. Productivity of 3.52 mol/kgads.h and 71.89 kgVCM/m3unit.h was achieved for an electrical energy consumption of 0.83 MJ/kgVCM.

Application of gas flow headspace liquid phase micro extraction coupled with gas chromatography-mass spectrometry for determination of 4-methylimidazole in food samples employing experimental design optimization.

Background4-Methylimidazole (4-MeI) or 4-methyl-1H-imidazole, a slightly yellowish solid with molecular formula C4H6N2, is a heterocyclic compound which supposedly does not exist as a natural product and is formed when carbohydrates are heating with ammonium compounds. This compound is used in pharmaceuticals, agriculture and photography chemicals, dyes and pigments, and rubber manufacturing. In the present study, a simple and efficient sample preparation method designated gas flow headspace liquid phase microextraction (GF-HS-SDME) was employed for the extraction and preconcentration of 4-methylimidazole (4-MeI) from food and beverage samples, before its determination by gas chromatography-mass spectrometry.ResultTo investigate the optimal conditions for the extraction process in GF-HS-SDME method, factors affecting extraction, including selection of extraction solvent, vial volume, extraction solvent ratio, position of extracting solvent, drop volume, sample volume, stirring speed, temperature, extraction time, sample pH, ionic strength of the sample solution and gas flow rate were optimized by utilizing both one-variable-at-a-time method and Plackett–Burman design. The investigation of protocol was carried out by using a standard solution containing 100.0 μg L−1 of 4-MeI in deionized water.ConclusionIn this study, a simple and green analytical method based on GF-HS-SDME was proposed for the extraction and preconcentration of 4-MeI from foodstuffs, followed by GC–MS determination. The main advantage of this method is its high preconcentration factor and fastness due to the application of an inert gas stream during microextraction.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13065-022-00823-z.

Utilization of Hematite Particles for Economical Removal of o-xylene in a High-Temperature Gas-Solid Reactor.

To establish a novel approach for VOCs resource utilization, coupled o-xylene oxidation and hematite reduction was investigated in this study in a high-temperature gas-solid reactor in the temperature range 300–700 °C. As the o-xylene-containing inert gas (N2) stream traveled through the hematite particle bed, its reaction behavior was determined in programmed heating and constant temperature modes. Consequently, the effect of bed temperature, flow rate and o-xylene inlet concentration on both o-xylene removal performance and degree of hematite reduction was studied. The raw hematite and solid products were analyzed by TGA, XRF, XRD and SEM-EDS. The results showed that a temperature above 300 °C was required to completely eliminate o-xylene by hematite, and both o-xylene removal capacity and degree of hematite reduction at 5% breakthrough points enhanced on increasing the temperature and decreasing the flow rate. The increment in temperature from 300 °C to 700 °C led to a gradual reduction of Fe2O3 to Fe3O4, FeO and metallic iron. Thus, this study provides a novel, economic and promising technology for treating the VOC pollutants.

Purification of Hydrogen from CO with Cu/ZSM-5 Adsorbents.

The transition to a hydrogen economy requires the development of cost-effective methods for purifying hydrogen from CO. In this study, we explore the possibilities of Cu/ZSM-5 as an adsorbent for this purpose. Samples obtained by cation exchange from aqueous solution (AE) and solid-state exchange with CuCl (SE) were characterized by in situ EPR and FTIR, H2-TPR, CO-TPD, etc. The AE samples possess mainly isolated Cu2+ cations not adsorbing CO. Reduction generates Cu+ sites demonstrating different affinity to CO, with the strongest centres desorbing CO at about 350 °C. The SE samples have about twice higher Cu/Al ratios, as one H+ is exchanged with one Cu+ cation. Although some of the introduced Cu+ sites are oxidized to Cu2+ upon contact with air, they easily recover their original oxidation state after thermal treatment in vacuum or under inert gas stream. In addition, these Cu+ centres regenerate at relatively low temperatures. It is important that water does not block the CO adsorption sites because of the formation of Cu+(CO)(H2O)x complexes. Dynamic adsorption studies show that Cu/ZSM-5 selectively adsorbs CO in the presence of hydrogen. The results indicate that the SE samples are very perspective materials for purification of H2 from CO.

Collection and Characterization by Mass Spectrometry of the Neutral Serine Octamer Generated upon Sublimation.

Serine forms neutral octameric clusters during sublimation, as demonstrated by electrostatically deflecting thermally ionized serine species from the sublimate, then gently ionizing the remaining neutrals for examination by mass spectrometry (MS). The MS results demonstrate a strong homochiral preference in the neutral octamer (measured after its gentle ionization), while the smaller serine clusters are achiral. In the initial stages of its sublimation, nonracemic solid serine generates a neutral serine monomer as the principal species in the vapor phase, with a significant enantiomeric enrichment relative to the solid. The serine monomer, when the flux is sufficient, assembles into the octamer, which displays a much higher chiral purity than the monomer. The serine octamer is separated from other neutral clusters in the sublimate by a new method based on the different distances that the clusters travel in an inert gas stream before they condense in a cooled collector. The deposited octamer is subsequently dissolved, and the solution is investigated by MS. The spectrum confirms that the collected serine octamer has undergone chiral enrichment relative to the starting solid used in the sublimation. The chiral enrichment observed in going from the serine monomer to octamer can be accommodated using a chemical model, grounded on the homochiral preference of the neutral serine octamer. Using the enantiomeric excess (ee %) of the vapor-phase monomer as the input, the model output matches the experimental octamer ee % when subliming solid serine with various initial ee % values.

Electrochemical CO2 reduction to high-concentration pure formic acid solutions in an all-solid-state reactor

Electrochemical CO2 reduction reaction (CO2RR) to liquid fuels is currently challenged by low product concentrations, as well as their mixture with traditional liquid electrolytes, such as KHCO3 solution. Here we report an all-solid-state electrochemical CO2RR system for continuous generation of high-purity and high-concentration formic acid vapors and solutions. The cathode and anode were separated by a porous solid electrolyte (PSE) layer, where electrochemically generated formate and proton were recombined to form molecular formic acid. The generated formic acid can be efficiently removed in the form of vapors via inert gas stream flowing through the PSE layer. Coupling with a high activity (formate partial current densities ~450 mA cm−2), selectivity (maximal Faradaic efficiency ~97%), and stability (100 hours) grain boundary-enriched bismuth catalyst, we demonstrated ultra-high concentrations of pure formic acid solutions (up to nearly 100 wt.%) condensed from generated vapors via flexible tuning of the carrier gas stream.

Performance of Different Catalysts for the In Situ Cracking of the Oil-Waxes Obtained by the Pyrolysis of Polyethylene Film Waste

Currently, society is facing a great environmental problem, due to the large amount of plastic waste generated, most of which is not subjected to any type of treatment. In this work, polyethylene film waste from the non-selectively collected fraction was catalytically pyrolyzed at 500 °C, 20 °C/min for 2 h, in a discontinuous reactor using nitrogen as an inert gas stream. The main objective of this paper is to find catalysts that decrease the viscosity of the liquid fraction, since this property is quite meaningful in thermal pyrolysis. For this purpose, the three products of catalytic pyrolysis, the gaseous fraction, the solid fraction and the liquid fraction, were separated, obtaining the yield values. After that, the aspect of the liquid fraction was studied, differentiating which catalysts produced a larger quantity of waxy fraction and which ones did not. The viscosity of these samples was measured in order to confirm the catalysts that helped to obtain a less waxy fraction. The results showed that the zeolites Y and the zeolites β used in this study favor the obtaining of a compound with a smaller amount of waxes than for example catalysts such as FCC, ZSM-5 or SnCl2.

A comparative study on corrosion behavior of ceramic coatings via plasma spray process in 3.5% NaCl solution

In the plasma spray process, material flows through a plasma arc and the molten particles are projected through an inert gas stream with high velocity on AISI 304L stainless steel sheet to give a coating with some degree of metallurgical bonding. This study discusses the effectiveness of particle size, type of coating and direction on the corrosion of ceramic coating in 3.5 % NaCl solution. Two approaches were used for preparing coated specimens. The first modification proposed to use coarse grain sized powder in spraying as the first layer followed by the fine one. The second trial assumes to change the coating direction of the top layer to be traversing the lower layer. WC-12% Co/Al2O3 coatings were deposited on AISI 304L stainless steel by means of a plasma spray process by different deposition techniques. For comparative purposes, a set of ceramics coatings via plasma spray process was employed on a substrate with Al2O3, and WC−12% Co. Potentiodynamic polarization measurements were carried out to determine the corrosion behavior of the plasma-sprayed-coatings in 3.5% NaCl. The results showed that the corrosion resistance depends strongly on the type of coating and on its direction of coating. The grain type combination showed a great influence on the corrosion behavior of the plasma coatings, the coarse WC-12% Co covered by fine Al2O3 showed a much better corrosion resistance than the fine WC-12% Co covered by coarse Al2O3.The parallel layers of coating specimen has the best corrosion resistance between the coated specimens with lowest corrosion rate 0.425 mm/year

Electrochemically generated standard additions for gas chromatography: case study of O2 and H2 analysis

The method of standard additions with electrochemically generated spikes was elaborated and demonstrated on examples of O2 and H2 chromatographic analysis in standard mixtures. While oxygen portions may be generated directly in a stream of inert gas by solid-state electrolysis, a standard hydrogen-containing mixture is introduced into the electrochemical cell followed by controlled electrochemical consumption of hydrogen. In both cases the analysis characteristics are similar: the recovery is 90-120% and exhibits a slight sensitivity towards the flow rate of the analyzed oxygen-containing gas. The relative error associated with the non-ideal proportionality between the spike and chromatograph signal is within 10-15% for operation in the optimum concentration region. The major factors affecting the accuracy of the analysis are associated with detector characteristics, particularly influenced by the sample dilution, precision of flow controllers and linearity of the function "signal vs. spike." The lowest errors of determination were found to be for the analyte content range 1-5% while at oxygen and hydrogen concentrations below 0.5% the interference of the signal associated with other components may lead to overestimated results. Graphical abstract Scheme of the gas line used for oxygen determination with electrochemically generated standard additions (method 2). Inset shows an example of oxygen content calculation using the dependency "chromatographic signal vs. current."

Phase Composition and Structure of Titanium Carbide/Nickel Binder Synthesis Products

We have studied the phase composition and structure of titanium carbide with a nickel binder prepared by self-propagating high-temperature synthesis in a cocurrent inert or reactive gas stream using granulated mixtures containing different grades of titanium. The results demonstrate that, unlike in the case of powder mixtures with a loose bulk density, the products of combustion of a granulated Ti + C + 25% Ni mixture in flowing nitrogen or without it retain their structure and granule size and can readily be ground into powder. In the case of the powder mixture both in a flowing gas and without it and in the case of the granulated mixture in flowing argon, the combustion products have the form of unbreakable sinter cakes, independent of the grade of titanium. Microstructural analysis of the combustion products points to spontaneous dispersion of the titanium particles surrounded by the nickel binder, independent of the starting mixture (granules or powder with a loose bulk density). Moreover, the phase composition of the synthesis products depends on the size and morphology of the titanium particles. In the case of PTM titanium, the final synthesis product consists of titanium carbide and nickel phases. After the combustion of mixtures based on PTM-1 titanium powder or a 50% PTM + 50% PTM-1 mixture, the final product consists of TiC, Ni, and TixNiy intermetallic phases. Synthesis in flowing nitrogen has been shown to change the phase composition of the combustion products of the mixtures based on PTM-1 titanium powder and a 50% PTM + 50% PTM-1 mixture, causing the intermetallic phases to disappear. To account for the combustion behavior of the mixtures, we have proposed a two-step mechanism of interaction in the Ti + C + 25% Ni system.

Numerical study on a novel burner designed to improve MILD combustion behaviors at the oxygen enriched condition

Despite the higher efficiency, oxygen-enriched combustion (OEC) suffers from high NOx emission. To promote its application, this paper proposes a new conceptual burner which could maintain the high efficiency while effectively reduce NOx emission. The burner is basically developed based on the concept of moderate or intense low-oxygen dilution (MILD) combustion, but the further novelty lies in the isolation of fuel and oxygen by an inert gas stream, which is supposed to postpone the reaction between fuel and oxygen and accelerate the establishment of MILD combustion regime.CFD (Computational Fluid Dynamics) simulation work has been conducted under three oxygen concentrations (19.5%, 23%, and 26.5%) to investigate the combustion behaviors of the novel burner following a detailed validation of the experimental case employing the original MILD combustion burner. Comparisons are made between the present proposed burner and the original burner in terms of temperature and species distributions, as well as NOx emission, for the three oxygen concentrations. The numerical results show that applying the novel burner can reduce the peak temperature obtained with the original burner by 106 K, 62 K and 58 K in three oxygen concentrations respectively. Meanwhile, the standard deviations of the temperature decreases by 24–54% in the special line, and all approximately 10% in the symmetric plane in the three oxygen concentrations. These observations suggest the enhanced uniformity of temperature distribution by using the novel burner, which is mainly due to the extended reaction zone together with the postponed reaction. As a result of the well-established MILD combustion status, the NOx emission can be reduced to 1/8, 1/5 and 1/2 of the original magnitude when using the novel burner at the oxygen concentration 19.5%, 23%, and 26.5% respectively.

Cold Physical Plasma Decreases the Viability of Lung Adenocarcinoma Cells.

The high mortality rate that accompanies cancer spurs the search for new methods that can be used to treat malignant neoplasms. In addition to chemotherapy, electrophysical techniques for tumor treatment appear rather promising. The results of in vitro exposure of A549 human lung adenocarcinoma cells to cold atmospheric plasma (CAP) are hereby presented. A gas-discharge device that generates a sequence of streamers propagating along a stream of inert gas in the ambient air was used. In the zone where the plasma jet came into contact with the target object, there were high-intensity electric fields and high plasma concentrations, while the gas temperature changed by less than a degree. In this study, we compared the cytotoxic effect of CAP in helium and argon. Direct irradiation of cells by CAP with U = 4.2 kV for 30–120 s was shown to reduce cell viability by 25%. Variation of the amplitude of the AC voltage in the plasma device in argon within a range of 3.8–5.6 kV did not significantly alter the cell death rate. Further optimization of the modes of CAP generation in gas-discharge devices with various geometries for the trea

Determination of 1-pyrenol in urine by gas chromatography with mass selective detector

Urinary 1-pyrenol belongs to the biological markers of exposure to the polyaromatic hydrocarbons. Several methods for the determination of 1-pyrenol in urine necessarily include enzymatic hydrolysis, extraction from the biological sample, and derivatization with the silylating agent. Enzymatic hydrolysis and silylation take very long time: 16 hours and 40 minutes respectively. A shorter and more sensitive version of the determination of 1-pyrenol in urine by gas chromatography with mass-selective detection is proposed. Enzymatic hydrolysis with β-glucuronidase is used for 1h to digest the conjugated form of 1-pyrenol (as glucuronide). After the enzymatic hydrolysis, the analyte is extracted from the biological matrix by hexane extraction, followed by evaporation of the extract to dry residue in an inert gas stream. The optimum conditions for liquid extraction are established by varying the ratio of salting out agent : extraction time : extraction ratio. The dry residue is re-dissolved and derivatized in the silylating reagent N, O-bis (trimethylsilyl) trifluoroacetamide (BSTFA) into trimethylsilyl ether at room temperature for 5 minutes. The analysis of the trimethylsilyl extract is carried out by gas chromatography on HP-5MS capillary column with mass-selective detection. The analyte is identified by the retention time and the ratio of the main and confirming ions. The high-accuracy determination is ensured by using the internal standard 1-pyrenol-d 9 . The range of detectable concentrations of the method is from 0.1 to 100 μg/l. Repeatability and interlaboratory precision are 4.4% and 6.4% respectively. The systematic error turns out to be insignificant. The accuracy is 14%. The method is tested on the urine samples of workers with the main professions in the aluminum production industry. Key words : 1-pyrenol, urine, gas chromatography-mass spectrometry, enzymatic hydrolysis, silylation (Russian) DOI: http://dx.doi.org/10.15826/analitika.2019.23.4.007 A.N. Alekseenko, O.M. Zhurba, A.V. Merinov FSBSI East-Siberian Institute of Medical and Ecological Research 12-a district, 3, Angarsk, 665827, Russian Federation

Mathematical and Numerical Modeling for Energy Valorization of Sugarcane

This study concerns the numerical modeling of the pyrolysis of sugarcane waste. The potential application of pyrolysis products obtained (fuel) is in use in domestic or industrial combustion plants. To facilitate the digital modeling of the process of pyrolysis, the waste particles are assumed arranged in a vertical cylindrical enclosure (fixed bed). Their heating is provided by an ascending vertical stream of hot inert gas. Solving the equations of the balances on a two-dimensional flow and nonstationary provides the axial development of the temperature, the solid concentration of the carbonaceous residue (coke) and the pyrolysis gas. The method of finite differential was used for spatial discretization of the equation system, and method of Rang-Kutta order4. After validation, this model was applied to a configuration of a fixed bed. The results are in good agreement with the experimental results reported in the literature.

Phosphorus Dendrimer Derived Solid Sorbents for CO2 Capture from Post-Combustion Gas Streams

Solid amine sorbents were prepared via cross-linking of polyamine compounds and polyaldehyde phosphorus dendrimers through a reductive amination approach. The CO2 adsorption capacities from inert gas streams and simulated flue gas were determined using a thermogravimetric analyzer (TGA) and a packed-bed reactor, (PBR) respectively. The sorbents adsorbed CO2 from inert CO2 gas streams up to 7.3 wt % at 65 °C and 10.7 wt % at 25 °C, while adsorbing CO2 from simulated flue gas up to 7.4 wt % at 65 °C. The amines are covalently bound in the sorbent, providing a robust material that is stable at elevated temperatures and does not leach upon exposure to moisture. The sorbents underwent extensive cycle testing, with no degradation observed up to 45 cycles on the TGA and up to 25 cycles on the PBR, while displaying rapid kinetics for both adsorption and desorption of CO2.

PO-463 Multiparametric analysis of lung cancer tissue sections using imaging mass cytometry

IntroductionA novel tool for multiparametric molecular pathology analysis of tissue sections is described. Imaging Mass Cytometry (IMC), a new mass spectrometer-based technology, provides visualisation and spatial distribution of up to 40 markers in a single tissue section with 1 µm resolution. IMC uses metal-tagged antibodies (mtAbs), a pulsed UV laser for ablating regions of interest, and a stream of inert gas to transfer material generated by the laser to the mass cytometer.1Material and methodsTissue microarray (TMA) of human lung cancer was stained according to IMC protocol2 using a mix of 23 mtAbs.The samples were inserted into the ablation chamber of the Hyperion Imaging System. CyTOF® Software v6.7 and MCD Viewer 1.0 were used for data acquisition and rendering of pseudo three-colour images. Quantification of selected markers was done with Definiens Tissue Studio® (DTS) software. Standard HPA protocol was used for immunohistochemical (IHC) staining.Results and discussionsIMC analysis of human lung cancer TMA stained with a panel of 23 mtAbs revealed that core morphology was consistent with anatomopathological tumour classification. Immune cell phenotype and spatial distribution assessed by IHC and IMC were equivalent.IMC generated data was used to quantitate PD-L1 marker expression. Percentages of cells expressing different levels of PD-L1 and average intensity of PD-L1 related signal were calculated for tumour and stroma regions of each core. In addition, PD-L1 corresponding signal intensity was calculated in cytoplasm and membrane compartments of marker-positive cells.ConclusionIMC technology is a powerful tool for multiparametric histopathological analysis. It allows researchers to simultaneously detect up to 40 markers with single-cell detection resolution equivalent to conventional IHC. Using DTS software we demonstrate quantitation of multiple markers in lung tumour sections probed with a panel of 23 mtAbs.ReferencesChang Q, Ornatsky OI, Siddiqui I, Loboda A, Baranov VI, Hedley DW. Imaging Mass Cytometry. Cytometry A 2017;91:160–169.Chang Q, Ornatsky O, Hedley D. Staining of frozen and formalin-fixed, paraffin-embedded tissues with metal-labeled antibodies for Imaging Mass Cytometry analysis. Curr Protoc Cytom, 2017;82(October):12.47.1–12.47.8.

A fundamental study on the thermal decomposition and combustion behaviors of guanidine nitrate and basic copper nitrate mixture

Energetic materials such as a mixture of guanidine nitrate (GN)/basic copper nitrate (BCN) are used as gas generators in automotive airbag systems. However, at the time of the airbag inflation, the gas generators release toxic combustion gases such as CO, NH3, and NOx. In this study, we investigated the combustion and thermal decomposition behaviors of GN/BCN mixture, focusing primarily on their exhaust gas composition. As a result, when the exhaust gas of the combustion under constant pressure in an inert gas stream was analyzed using a detection tube, the amount of NOx (mainly NO) yielded greater decrease with increasing atmospheric pressure as compared to the amounts of CO and NH3. Thus, provided GN/BCN is ignited in a closed container, a large amount of NOx is presumed to have been released during the initial stage of combustion, which yielded comparatively low pressure. Results of the thermogravimetry–differential scanning calorimetry–Fourier transform infrared spectroscopy (TG/DSC/FTIR) indicated that the GN/BCN mixture caused endothermic decomposition at 170 °C and exothermic decomposition at 208 °C, which was accompanied by 66% mass loss. The decomposition gases, CO2, N2O, and H2O, were detected via FTIR spectrum. Because N2O was not detected in the combustion gas, it was suggested that the detected N2O was generated at a low temperature and decomposed in high-temperature combustion.

Thermal behavior of methoxy-substituted Pd and Cu β-diketonates and their heterobimetallic complex

The thermal behavior of volatile heterometallic CuPdL4 compound and parent β-diketonate complexes CuL2 and PdL2 (L = 2-methoxy-2,6,6-trimethylheptane-3,5-dionate; (CH3)3CCOCHCOC(CH3)2OCH3) were investigated by different methods. It is demonstrated that the combination of data on the gradient sublimation, TG–DTA, the mass transfer in a stream of inert gas and mass spectrometry can determine the composition of the gas phase. The volatility of the heterometallic complex was shown to follow the vapor-phase composition presented by binuclear [CuL2PdL2] molecules, and there was no decomposition into monometallic complexes within the studied temperature range (403–438 K). Temperature dependences of the saturated vapor pressure were obtained, and thermodynamic parameters of the sublimation process were computed for these three compounds for the first time. The thermal decomposition of the bimetallic complex vapor was found to start with the surface reaction of dissociation into monometallic complexes followed by their thermolysis with the formation of Cu/Pd alloy films.

Position dependent surface quality in selective laser melting

AbstractAdditive manufacturing receives nowadays opulent attention in both media and ongoing research. In particular, the techniques involving full melting of the raw material, enabling the fabrication of directly deployable components, are of high interest. To date, there are still secondary influences which are yet to be considered, leading to substantial, mainly directional dependent, deviations. The study at hand investigated the surface roughness dependencies in plane, focusing on the interaction of the unidirectional inert gas stream with the irradiation sequence; more precisely the weld splashes emerging from the melt pool, and the resulting in plane pattern. The surface roughness of the upwards orientated faces revealed clear fluctuations, being lowest close to the gas‐inlet and also in the back area of the machine. Perpendicular to the fabrication plane aligned surfaces did not reveal any volatility regarding the inert gas stream. Increasing the energy density of the irradiation led to an increase in the surface roughness of all side faces, but to an improved roughness of the upwards facing surfaces coupled with a significant reduction in evident weld splashes.