Melting Procedure Research Articles

Exploring wear, corrosion, and microstructure in PEO coatings via laser surface treatments on aluminum substrates

The inadequate resistance to corrosion and wear of Al-based alloys is a major hindrance to their extensive use. Plasma electrolytic oxidation (PEO), a common and efficient coating technique, creates an oxide coating similar to ceramic on the surface of Al-based alloys, thereby improving their ability to withstand corrosion and wear. Studies have shown that PEO treatment can significantly enhance the short-term corrosion and wear resistance of Al-based alloys. To improve the long-term corrosion resistance of PEO coatings, researchers are now exploring the combination of laser processes with the PEO process. Laser processing is a simple yet efficient technique known for its flexibility, precision, and control. Various laser procedures are recognized for their ability to improve the resistance to wear and corrosion of PEO coatings applied on Al substrates and their alloys. Laser melting procedures have the capability to standardize and modify the microstructure of aluminum-based alloys. This review focuses on enhancing the anti-corrosion and anti-wear properties of aluminum alloys through the integration of laser surface treatments with PEO technology.

Comparative kinetics and enhanced desalination efficiency of hydrate-based desalination using HFC-125a, HFC-134a, and HFC-152a through hydrate pelletization and induced melting

The present study demonstrates the feasibility of gas hydrate technology for effective desalination of salt water without requiring pre- or post-treatment. The research highlights two main aspects: the thermodynamic and comparative kinetic properties of hydrofluorocarbon (HFC) gases, and the novel concept of hydrate pelletization enhanced by an induced pellet melting procedure. The thermodynamic viability of HFC gases such as HFC-125a, HFC-134a, and HFC-152a for hydrate formation in both saline and non-saline conditions is underscored. For the first time, a comparative analysis of the gas uptake kinetics for these three gases is presented under 0, 3.5, and 8.0 wt% NaCl conditions. Results indicate that HFC-134a and HFC-152a exhibit rapid gas uptake kinetics, while HFC-125a shows sluggish kinetics, attributed to the effective pressure driving force and subcooling temperature. Regardless of the guest gas, the chosen experimental conditions achieved salt removal efficiency of ~70 % in 3.5 wt% NaCl and ~ 75 % in 8.0 wt% NaCl. The novel induced hydrate pellet melting approach significantly improved salt removal efficiency, exhibiting a nonlinear behavior where the rate of salt removal efficiency increases asymptotically as more hydrate melts. New insights into salt distribution within the hydrate pellet reveal that the core contains higher salinity, than the outer layer.

Microstructure evolution and crack prevention in TiC nanoparticles-enhanced 2195 Al[sbnd]Li alloy joint fabricated by coaxial fiber-diode hybrid laser wire-feeding welding

High hot crack susceptibility (HCS) in laser-welded 2195 AlLi alloy poses a considerable challenge that restricts its widespread application. Nonetheless, the utilization of advanced laser beam shaping technology and nano-technology presents novel approaches to modify the melting and solidification procedures, enabling precise control over microstructure and crack. Herein, a crack-free and well-formed weld seam (WS) of 2195 AlLi alloy was successfully achieved by employing a coaxial “Gussies + Flat top” hybrid laser source and introducing TiC nanoparticles. The contrast experiments were performed to comprehensively investigate the effect of TiC nanoparticles on the microstructure evolution and hot cracks in welded joints of 2195 AlLi alloy. The results indicated that the crack propagation occurs linearly along the grain boundaries of columnar dendrites and laterally along the grain boundaries of equiaxed dendrite utilizing the conventional AlCu filling wire. With the assistance of TiC nanoparticles, the crack-free WS with homogeneously equiaxed dendrites is facilitated. The elimination of cracks by introducing TiC nanoparticles is attributed to the ameliorative liquid feeding channels, grain refinement, as well as the the pinning effect of TiC nanoparticles.

Single-Scan Heteronuclear 13C-15N J-Coupling NMR Observations Enhanced by Dissolution Dynamic Nuclear Polarization.

Heteronuclear 13C-15N couplings were measured in single-scan nuclear magnetic resonance (NMR) experiments for a variety of nitrogen-containing chemical compounds with varied structural characteristics, by using a one-dimensional (1D) 13C-15N multiple-quantum (MQ)-filtered experiment. Sensitivity limitations of the MQ filtering were overcome by the combined use of 15N labeling and dissolution dynamic nuclear polarization (dDNP), performed at cryogenic conditions and followed by quick and optimized sample melting and transfer procedures. Coupling information could thus be obtained from nucleotide bases, amino acids, urea, and aliphatic and aromatic amides, including the measurement of relatively small J-couplings directly from the 1D filtered spectra. This experiment could pave the way for NMR-based analytical applications that investigate structural and stereochemical insights into nitrogen-containing compounds, including dipeptides and proteins, while relying on heteronuclear couplings and nuclear hyperpolarization.

Dielectric relaxation studies in Sm2O3 doped boro-zinc-vanadate glasses

In this work, the conventional melting procedure was adopted to synthesize glasses with a composition of (ZnO)0.3 – (V2O5)0.3 – (B2O3)0.4-x – (Sm2O3)x, x = 0.002, 0.005, 0.007, 0.01 and 0.02 mol%. The dielectric properties of these glasses were measured. The dielectric constant (εʹ) and dielectric loss (εʹʹ) of glasses are found to vary in the range from 1.9177x102 to 3.9456x103 and from 1.5751 to 6.9095x105 respectively for the temperature range 343 K – 573 K and frequency range 50 Hz to 10 MHz. With increase of frequency, both dielectric constant and loss decreased and increased with increase of temperature. The analysis of dielectric constant and dielectric loss confirmed that the phenomenon of dielectric relaxation is mainly due to the frequency-dependent polarization mechanism. Electric modulus and impedence spectroscopy revealed non-Debye type and a single phase relaxation process. Activation energy for dc conductivity and dielectric relaxation are found to be of same size indicating that the potential barrier encountered by the charge carriers is same in both the processes. The master curves suggested that temperature-independent relaxation is occurring in the present glasses. The high values of measured dielectric parameters suggest that the present glasses are suitable in semiconducting and energy storage applications.

Influence of micro-addition of lanthanum on grain characteristics, mechanical properties, and corrosion behavior of CuAlNiMnLa shape memory alloy

The study investigated the grain size criteria, mechanical characteristics, and corrosion behavior of Cu-14Al-4.5Ni-0.7Mn shape memory alloy (SMA) with the micro-addition of 0.06 wt% Lanthanum (La). Using standard melting and casting procedures, the alloy compositions were melted at 1300 ℃ in an arc furnace with an argon atmosphere. The cast compositions without thermal treatment were machined and tested for physical properties including density and percentage porosity, corrosion behavior, and mechanical properties like hardness, ultimate tensile strength, yield strength, fracture strain, percentage elongation, specific strength, and fracture toughness. The average grain size, profile plot, and grain size distribution were all determined using ImageJ software. The microstructural observations revealed the presence of α-phase, β-phase, and intermetallic phases, including the coarse α+γ2 phase, which contributed to the improved characteristics. The inclusion of lanthanum resulted in a drop in the average grain size of the parent alloy from 9.25 μm to 6.08 μm, indicating a clear correlation between property improvement and microstructure refinement. The composition's tensile strength and yield strength increased with the La micro-addition by 22.14% and 20.31% respectively while the hardness value increased by 17.3%. The fracture strain of the modified composition increased by 20% compared to the unmodified composition while the percentage elongation increased by 7.7% and a 22.5% increase in fracture toughness was achieved. The modified CuAlNiMn SMA also showed a significant improvement in corrosion resistance to NaCl solutions which was so evident at 144 hours of the study for 0.5 M of NaCl solution and at 96 hours for 1.0 M of NaCl solution. The results showed that CuAlNiMn SMA with micro-addition of La had better physical, corrosion, and mechanical characteristics than unmodified CuAlNiMn alloys

Influence of platinum content (X) in the LaNi5PtX catalyst and reaction conditions on the properties of ferromagnetic Ni-filled CNTs

This research highlights the synthesis of carbon nanostructures using the catalytic chemical vapor deposition (CCVD) method, a hybrid process combining chemical vapor deposition (CVD) and Gas-Solid Heterogeneous Catalysis (GSHC). Intermetallic catalysts, LaNi5Ptx (x = 0, 0.05, 0.5, 1.0), were fabricated through an arc melting procedure to serve as templates for the catalytic conversion of carbon precursors into solid materials. These catalysts, featuring the ferromagnetic transition metal Ni, tend to aggregate into larger particles, reducing the rate of hydrocarbon cracking at the catalyst surface. Rare earth metals like Lanthanum were introduced to form an alloy with a higher melting point to prevent thermal aggregation. Additionally, Pt was incorporated to modify the catalytic properties of the alloy. The study primarily explores the impact of catalyst composition on carbon nanotube (CNT) production. The introduction of platinum content to the catalyst influences the rate at which Ni is filled. The research aimed to alter the catalyst's composition by varying platinum doping in the Pauli paramagnetic lanthanum nickel alloy (LaNi5) to understand the growth mechanism and morphological variations of Ni-filled CNTs. Platinum and lanthanum oxides significantly influence nickel filling in CNTs, resulting in an increased filling rate as the catalyst's Pt content varies from 0 to 1.0. However, higher Pt doping content disrupts the CNT structure with spontaneous nickel encapsulation.

Improved thermoelectric properties of Sb-doped Ti0.5Zr0.5NiSn alloy with refined structure induced by rapid synthesis processes

Thanks to the great advantage of preparation methods, the thermoelectric (TE) alloy materials can be fast synthesized with controllable structural morphology for optimizing charge and phonon transport properties, thereby improving the TE efficiency of the material. Herein, a series of Sb-doped Ti0.5Zr0.5NiSn1−xSbx based half-Heusler alloy was prepared via a combined fast procedure of arc melting (AC), melt spinning (MS) followed by spark plasma sintering (SPS). The detailed analyses of morphology, phase structure, and composition reveal high-quality samples through processes for enhanced TE properties. High ZT values over one are achieved for all samples with slight Sb doping content variation from x = 0.0025–0.02. The enhanced TE performance of the Sb-doped Ti0.5Zr0.5NiSn1−xSbx alloys here results from the synergistic between the approaches such as doping, alloying, nanostructuring, and the presence of nano-precipitates induced by MS. The highest ZT values of ∼1.2 at 847 K with an average ZT of 0.798 and estimated TE conversion efficiency reached 12.8% in the temperature range from 300 K to 847 K were achieved for the 1.25% Sb doped sample. In addition, the thermal cycling test through continuous measurement of five and a half cycles confirmed the high thermal stability of the bulk alloy. High ZT and thermal stability based on Hf-free Ti0.5Zr0.5NiSn1−xSbx alloy and fast synthesis are well matched for commercial requirements.

Densification-crystallization behavior of biodegradable copper-doped modified 45S5 glasses

In the current work, modified 45S5 glasses containing different amounts of copper oxide (1, 3, and 5 weight ratios) were prepared using melting procedure and characterized for their physical properties after sintering at various temperatures. Characterization of the copper doped glasses was performed using various analytical techniques, including X-ray diffractometry, differential thermal analysis, and scanning electron microscopy. To this purpose, a systematic study was conducted on densification-crystallization of the copper doped glasses and optimizing sintering temperature. Differential thermal analysis revealed weak exothermic peaks located above 800 °C, corresponding to the crystallization temperature (Tc) of the studied glasses. This analysis suggests that copper oxide has a limited effect on the thermal properties of the modified 45S5 glasses. Densification behavior of glass specimens was studied at temperatures ranging from 600 to 850 °C. The optimal densification temperature was found to be 650 °C, respectively. The results indicated that the presence of copper ions in the structure of studied glasses results in the formation of porous structures after sintering. It seems that copper ions generate oxygen gas during sintering and promote the formation of a cellular foam structures.

Modification of structure and properties of fluoro-sulfo-sodium alumino-phosphate glass through additional fluorine and sulfur agents

Laser glass has been widely used in laser ignition devices, fundamental physical research, and material processing. In addition to the exploration of the glass composition, the optimization of preparation conditions is also of crucial importance to the performance of laser glass. Herein, the modification effect of additional fluorine and sulfur agents on Nd3+-doped fluoro-sulfo-phosphate glasses (FSP) has been investigated in detail. The contents of F and S were increased by up to 42% and 40% after agent addition. Fluorine and sulfur agents also decrease the non-linear effect and increase the chemical durability of FSP glasses, respectively. Moreover, the local environment around Nd3+ ions is examined by electron paramagnetic resonance (EPR)., The direct connection between Nd-F and the possible connection between Nd3+ and [SO4]2− have been detected with agent addition, which facilitate the promotion of radiation parameters. The emission cross-section and quantum efficiency of FSP glass increase by up to 56% and 54% after agent addition. This study aims to demonstrate the structure and property variations brought by additional agents, providing insight into the optimization of the melting procedure of high-performance FSP laser glasses.

Synthesis of a polyester with a liquid crystalline silsesquioxane-contained backbone Chain

A one-pot multistep growth melt procedure utilizing multistep feeding has been developed to enable the synthesis of thermoplastic polymers based on 4-hydroxybenzoic acid (HBA) and 6-hydroxy-2-naphthoic acid (HNA)with greater numbers of alternating units in their backbone chains. The decreased melting point (Tm) and glass transition temperature (Tg) indicated that the multistep feeding procedure helped to enhance the flexibility of the backbone chain due to the increasing number of alternating blocks, due to a reduction in the stacking between different main-chains, thus enabling the formation of liquid crystalline polyester (LCP) fibers with oriented structures. The covalent incorporation of rigid cage-like silsesquioxane groups led to a significant reduction of the melting point, resulting from the inevitable transformation of the original symmetrical backbone structure to a less ordered structure, due to the steric effect and hybrid feature of silsesquioxane. The presentation of silsesquioxane groups also enhanced the aggregation of ultrafine fibers with well-aligned orientation in the molten state and produce stronger fiber bundles.

Study on the Laser Melting Procedure for the Specified Zone of the TC4 Titanium Alloy

This paper presents an in-depth study of the variable reference process to improve the organization and properties of selective laser melting TC4 specimens. A relationship equation between body energy density and stratification is proposed. This study aimed to look into how layer and volume energy density affect the surface, tensile characteristics, and microstructure of specimens. The test findings demonstrated that specimen densities rise as the power index falls, with the most excellent density reaching 99.42%. The number of secondary α’ phases declined as the energy density of the laminae slowed down. The tensile strength of these specimens reached 1190.84 MPa, and the yield strength came at 1103.87 MPa with the same interval of variable laser power. This offers a fresh avenue for research into SLM to enhance the specimens’ overall performance.

Computational analysis of natural convection with water based nanofluid in a square cavity with partially active side walls: Applications to thermal storage

Heat transport induced by buoyancy caused natural convection inside a segmented or selectively heated enclosure has grown in importance over the decades due to its significance in many fields in industrial implementations such as heat source cooling, food sterilizers, crystal growth, geothermal power systems, solar thermal collectors, melting and recrystallization procedures, microelectronic and nuclear industries, biomedical, and so forth. The novelty of current modern analysis is to scrutinize the natural convection of Titanium Oxide-water nanofluid in the cavity with partially active walls simulated by the finite element (FEM) method. The fluid flow and the thermal transportation within the enclosure are scrutinized. Two cases are carried out in this novel study, heat sink with constant temperature Tc consists in case 1 from the left and right partially active cavity walls and isothermal heat source having temperature Th correspondingly, whereTh>Tc. While upper and lower walls with inactive portions of the left and right walls are kept insulated. In case 2 the left and right walls of the cavity are heated while a partially active bottom wall is cold with other inactive parts insulated by the cavity walls. The finite element method is applied to tackle the governing equations. The Significance of Rayleigh number (100⩽Re⩽1e6) and volume fractions of nanopowders (0.01⩽ϕ⩽0.06) against fluid flow and heat transfer is demonstrated through streamlines and isotherms. From the results it is concluded that velocity amount is increased with escalating the values of Rayleigh number. The thermal results are enhanced with Rayleigh number. Furthermore the heat transfer is rised with volume fraction of nanoparticles. Additionally, from the analysis reveals that local Nusselt number is enhanced with Rayleigh number and nanoparticle volume fraction.

Effective Removal of Methyl Orange Dyes Using an Adsorbent Prepared from Porous Starch Aerogel and Organoclay

Intending to provide efficient and compact wastewater remediation, the present work is exploiting and introducing a novel composite prepared from porous starch aerogel (PSA) and organically modified Ca-montmorillonite (OMMT) for the removal of dyes from aqueous samples. First, potato starch components were used as a hydrolysis precursor to obtain PSA. The organoclay samples were prepared by co-intercalation of octadecylamine (ODA) into Ca-MMT using a low-temperature melting procedure. Composites with different starch-to-organoclay ratios of 10:1, 1:1, and 1:10 were then prepared by a blending process in distilled water and used for methyl orange (MO) uptake. The removal of methyl orange dyes increased with the amount of organoclay in the PSA matrix. Characterization revealed that organoclay synergy improved the PSA surface chemistry, while an important improvement in textural properties and thermal stability was also observed. The composite’s efficiency was demonstrated by high removal capabilities towards MO in most experimental runs, with a maximum adsorption capacity beyond 344.7 mg/g. The fitting result showed that MO adsorption follows a monolayer adsorption model, and chemisorption was the rate-controlling step. Nonetheless, this study proved the great potential of PSA/OMMT in dyeing wastewater treatment. Furthermore, starch modification is proven as an effective approach to enhancing the performance of starch-derived adsorbents.

Magnetocaloric and Magneto-transport Properties in Polycrystalline Ni<sub>56</sub>Mn<sub>20</sub>Ga<sub>24</sub> Heusler Alloy

Polycrystalline ingots of Ni-rich Ni56Mn20Ga24 alloy were prepared by conventional arc melting procedure. The magnetocaloric and magnetotransport properties of the alloy were investigated within a temperature range from 4.2-300 K and up to a magnetic field of 8 T. A large magnetocaloric effect (∆SM ~ 29 J/Kg K) was observed in the alloy in the vicinity of magneto-structural transition temperature at a change of 5 T magnetic field. From magnetic measurements, it was observed that the martensite to austenite transition was accompanied by higher to lower magnetization in higher magnetic fields. The large entropy change was explained by considering the first-order magneto-structural transition in this alloy. A high negative magnetoresistance (⁓7 %) associated with magnetic field induced first order magneto-structural transition was also observed near room temperature due to a change of 8 T magnetic field for this alloy.

Thermodynamic Calculations of Direct Reduction Smelting Technology of Copper Oxide Ores Based on Smelting Slag from the Yubeidi Site, Yunnan Province

The current research on metallurgical remains from scientific excavations in northeast Yunnan from the Bronze Age period is insufficient. In order to study the smelting technology of the Bronze Age in north-eastern Yunnan, samples of slag and mineral excavated from the Yubei Di site in Dongchuan were examined. Based on the outcome of the characterization analysis, a simulation was executed utilizing the software Factsage 7.1 in order to generate a phase diagram that accurately portrays the melting procedure. This simulation aimed to produce the most credible representation of the phase transition by employing computational methods. Characterisation methods included Metallographic Microscopy, Scanning Electron Microscopy Energy Dispersive Spectromicropy (SEM-EDS), X-ray diffraction (XRD), and Radiocarbon Date (14C dating). The results showed that there was much copper ore left in the slag of the site. Most of these copper ores were in the form of copper ferrite or cuprous oxide. The copper ore was copper oxide ore, and metal copper particles appeared in a small amount of the slag. Most of the slags unearthed from the site of the Yubeidi site were products of sulfur-containing oxide reduction and smelting into copper. Based on the outcomes of the simulations, it was established that the slag excavated from the Yubeidi site was mainly from the reduction and smelting process of sulphur-containing copper oxide minerals into copper, without consciously adding fluxes, not having mastered the slag-making techniques for different types of copper ores, and with primitive techniques. The carbon 14 dating results show that the age of the slag was during the Spring and Autumn Period and the Warring States Period.

Key melt properties for controlled synthesis of glass beads by aerodynamic levitation coupled to laser heating

AbstractBinary alkali silicate glasses were synthesized as beads by aerodynamic levitation coupled to laser heating to test the applicability of the method to this compositional range. While bubble‐free lithium disilicate beads could be easily obtained, sodium and potassium silicates proved more challenging to melt without significant alkali evaporation: the final samples contained bubbles and exhibited compositional drifts compared to the starting stoichiometry, especially at high SiO2content. The risk of volatilization from the melts was evaluated empirically: the volatility of each oxide component scaled to the ratio between its melting temperatureTmand theTmof the target composition (revap), while the difference between such ratios (Δevap) provided a qualitative estimation of the risk of differential evaporation. The formulated approach enables to evaluate the suitability of aerodynamic levitation synthesis for a given target glass composition: while low melting temperature and low liquidus viscosity (η < 100 Pa s) represent the primary optimal conditions, more viscous materials can still be prepared without major compositional drifts using a more careful melting procedure, especially ifrevapandΔevapare minimized.

Effect of the crucible composition on the Inconel 718 vacuum induction melting process efficiency

Nickel-based superalloys are widely employed to manufacture aero-engine turbines due to their high mechanical strength and resistance to corrosion and creep. Vacuum Induction Melting (VIM) is a suitable manufacturing technology because of the reactive nature of the alloying elements; however, the melting process is time-consuming and energy-demanding. This research focuses on increasing the overall efficiency of the process in two ways. Initially, studying the influence of metal-containing crucible composition and thermal properties on the melting. In a semi-industrial VIM facility, 2 kg of Inconel 718 alloy was melted employing Al2O3, ZrO2, MgO, and Al6Si4O13-based crucibles. The Al6Si4O13 and ZrO2-based crucibles reduced energy consumption by 28% and 23%, respectively, compared to the reference crucible of Al2O3. Subsequently, an optimized melting procedure is proposed to reduce the process cycle time and energy demand, saving 10%–20% for all crucibles compared to the standard melting procedure. In addition, the ZrO2 and Al6Si4O13 crucibles reduced total cycle time by 13% and 21%, respectively. During melting, intense dross formation was detected for all crucibles, dissipating faster for Al6Si4O13 and MgO crucibles. Therefore, the metal-crucible interface product was analyzed to understand these mechanisms better, and the four crucibles' chemical reactivity was examined.

Study of the Methylation of Bovine GSTP1 Gene under the Influence of Pesticide Mospilan 20SP Alone and in Combination with Pesticide Orius 25EW.

DNA methylation, one of the most studied epigenetic mechanisms, when present in the promoter region of genes, causes inhibition of gene expression, and conversely, hypomethylation of these regions enables gene expression. DNA methylation is susceptible to nutritional and environmental influences, and undesirable alterations in methylation patterns manifested in changes in the expression of relevant genes can lead to pathological consequences. In the present work, we studied the methylation status of the bovine GSTP1 gene under the influence of pesticide Mospilan 20SP alone and in combination with pesticide Orius 25EW in in vitro proliferating bovine lymphocytes. We employed methylation-specific PCR, and when studying the effect of pesticide combinations, we also used its real-time version followed by a melting procedure. Our results showed that Mospilan 20SP alone at 5, 25, 50, and 100 µg.ml-1 and 5, 10, 25, and 50 µg.ml-1 for the last 4 and 24 hours of culture with in vitro proliferating bovine lymphocytes, respectively, did not induce methylation of the bovine GSTP1 gene. The same results were revealed when studying the effect of the combination of the pesticides added to the lymphocyte cultures for the last 24 hours of cultivation in the following amounts: 1.25, 2.5, 5, 10, and 25 µg.ml-1 of Mospilan 20SP and 1.5, 3, 6, 15, and 30 µg.ml-1 of Orius 25EW. We have also revealed that the less laborious real-time MSP followed by a melting procedure may replace MSP for studying the methylation status of the GSTP1 gene.

Impacts of sea ice melting procedures on measurements of microbial community structure

Microorganisms play critical roles in sea ice biogeochemical processes. However, microbes living within sea ice can be challenging to sample for scientific study. Because most techniques for microbial analysis are optimized for liquid samples, sea ice samples are typically melted first, often applying a buffering method to mitigate osmotic lysis. Here, we tested commonly used melting procedures on three different ice horizons of springtime, first year, land-fast Arctic sea ice to investigate potential methodological impacts on resulting measurements of cell abundance, photophysiology, and microbial community structure as determined by 16S and 18S rRNA gene amplicon sequencing. Specifically, we compared two buffering methods using NaCl solutions (“seawater,” melting the ice in an equal volume of 35-ppt solution, and “isohaline,” melting with a small volume of 250-ppt solution calculated to yield meltwater at estimated in situ brine salinity) to direct ice melting (no buffer addition) on both mechanically “shaved” and “non-shaved” samples. Shaving the ice shortened the melting process, with no significant impacts on the resulting measurements. The seawater buffer was best at minimizing cell lysis for this ice type, retaining the highest number of cells and chlorophyll a concentration. Comparative measurements of bacterial (16S) community structure highlighted ecologically relevant subsets of the community that were significantly more abundant in the buffered samples. The results for eukaryotic (18S) community structure were less conclusive. Taken together, our results suggest that an equivalent-volume seawater-salinity buffered melt is best at minimizing cell loss due to osmotic stress for springtime Arctic sea ice, but that either buffer will reduce bias in community composition when compared to direct melting. Overall, these findings indicate potential methodological biases that should be considered before developing a sea ice melting protocol for microbiological studies and afterwards, when interpreting biogeochemical or ecological meaning of the results.