Tendency For Formation Research Articles

Freckle Formation Tendency of a Single-Crystal Nickel-based Superalloy with Minor Carbon Additions

Freckle Formation Tendency of a Single-Crystal Nickel-based Superalloy with Minor Carbon Additions

Altered brain network stability in OCD following rTMS intervention: Insights from structural balance theory

Repetitive Transcranial Magnetic Stimulation (rTMS) is a promising intervention for Obsessive-Compulsive Disorder (OCD). However, understanding brain network changes following rTMS remains limited, despite its potential to enhance treatment efficacy. In this retrospective study, we investigated brain network reorganization in OCD patients after rTMS, using structural balance theory as a framework. We hypothesized that rTMS-induced functional plasticity would alter brain network topology, particularly affecting triadic associations, and leading to increased balance energy levels, indicative of a less stable network state. Brain functional networks were constructed from resting-state EEGs of OCD patients, with phase lag indexes calculated both before and after rTMS treatment. These networks were analyzed by comparing global parameters, including positive and negative links, triadic interactions (balanced/unbalanced), hub formation tendencies, and balance energy levels. We observed a significant decrease in weak-balanced triads and an increase in strong-unbalanced triads within the Beta І frequency band (12–15 Hz). Additionally, there was a notable reduction in the tendency of negative links to form hubs across certain frequency bands. These changes led to an increase in the network's balanced energy level, pushing it toward a less stable state. We hope these findings will refine rTMS strategies by facilitating brain network reorganization.

Impact of hBN Content on the Tribological Behavior and Thermal Diffusivity of HVOF-Sprayed Cr3C2-NiCr Coatings.

Considering the significant health risks posed by hard chrome plating during its application, thermally sprayed Cr3C2-NiCr cermet coatings represent a suitable alternative. Incorporating hexagonal boron nitride (hBN) as a dry lubricant into the feedstock powder can further enhance wear resistance and thermal conductivity, crucial for preventing premature failure caused by inadequate lubrication. In this study, the mass fraction of hBN was varied between 0 and 15 wt.% to assess its influence on the tribological performance of the coatings using pin-on-disk tests. The coating's hardness was measured via the Vickers method, and its cracking tendency at the coating/substrate interface was evaluated. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to analyze the microstructure and phase composition, while thermal diffusivity was determined using the laser flash method. The findings revealed that the inclusion of hBN, at concentrations of up to 10 wt.%, leads to an improvement in thermal diffusivity and a reduction in the coefficient of friction. However, exceeding this threshold leads to a decrease in hardness and increased crack formation tendency, highlighting the trade-off between frictional and mechanical properties.

Cation Vacancy-Mediated Ultrafast Hole Transport in CuBi2O4 Photocathodes.

In this study, the ultrafast transport dynamics of the valence band hole states in CuBi2O4 (CBO) photocathodes were investigated by varying the atomic composition and manipulating their p-type character. As a comprehensive ultrafast optical transient absorption spectroscopy (TAS) investigation of compositionally manipulated CBO that combines both ex situ and in situ TAS experiments with photoelectrochemical (PEC) performance tests, the study reveals the polaron formation tendencies of the valence band (VB) holes at cationic vacancy sites. Therefore, it draws a complete picture of the ultrafast hole transport dynamics and provides valuable insights into the hindrance of the photocurrent generated in CBO.

Manufacturing Aluminum-Based Nanocomposites via Stir-Squeeze Casting Combined with Ultrasonication

This study successfully produced aluminum nanocomposites using a stir-squeeze casting process, both with and without ultrasonication (US) assistance. The matrix material utilized was scrap automobile wheel aluminum alloy (A356), with 1% SiC nano particles, averaging a size of 40 nm, serving as the reinforcement material. A comparison was made by also producing A356 aluminum casts with and without the use of US. The produced casts underwent thorough chemical and mechanical characterization, including optical and scanning microscopy, porosity measurement, hardness measurement, compression and tensile testing, as well as wear testing. Additionally, energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses were conducted to assess compositions and confirm the presence of SiC nano particles in the aluminum matrix. Porosity levels were slightly higher in the nanocomposite samples compared to pure matrix samples, attributed to the tendency of pore formation due to improper distribution of ceramic particles, resulting in clustering and agglomeration. However, significant reduction in porosity was observed with the application of ultrasonication, effectively breaking up clusters and agglomerations of reinforcement particles. Regarding mechanical properties, the A356+SiC sample with US exhibited the highest hardness (70.8 HRB), tensile strength (163.25 MPa), and compressive strength (387.2 MPa), along with the lowest abrasive wear loss (0.0017 g) among all types of casts produced in this study.

Unveiling mechanisms and onset threshold of humping in high-speed laser welding

The fabrication of fuel cells relies on a rapid laser welding process. However, challenges arise with the occurrence of humping when the welding speed surpasses a critical threshold, which poses difficulties in achieving a smooth surface finish and a consistent weld strength. This study aims to elucidate the humping mechanisms by analyzing the morphology of molten pool and the characteristics of melt flow at varying welding speeds via in situ synchrotron high-speed X-ray imaging and computational fluid dynamics simulations. Our findings indicate that the short keyhole rear wall, the high backward melt velocity, and the prolonged tail of molten pool are the primary factors contributing to the onset of humping. Furthermore, a dimensionless humping index (πh\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\pi }_{h}$$\\end{document}) was introduced, which successfully captured the onset threshold of humping across different literatures. This index not only provides a quantitative description of the humping formation tendency but also serves as a valuable tool for optimizing the laser welding process.

Unveiling the interface characteristics of diamond/Al interface: First-principles calculations and experiments

In this work, both first-principles calculation and experiment results revealed different interface characteristics of (111) and (100) diamond/Al interfaces. Tensile simulations were applied to examine the fracture behavior of diamond(111)/Al(111), diamond(100)/Al(111), and diamond(100)/Al4C3(003) interfaces. The results demonstrate that the work of adhesion and the tendency for Al-C bond formation are significantly greater at the diamond(100)/Al(111) compared to the diamond(111)/Al(111) interface. The growth morphology arising from reactions between Al and various diamond crystal planes is closely linked to the distinct surface characteristics of the diamond. The diamond(100)/Al4C3(003)-C terminal interface shows the highest work of adhesion due to the synergistic effects of C–C and Al-C bonding, as well as the reconstruction of diamond C atoms. During tensile calculation, multilayer relaxation occurred on the Al4C3(003) side for diamond(100)/Al4C3(003)-C terminal interface, with the highest ultimate tensile strength. While the Al atoms near the diamond(111)/Al(111) interface undergoing a clean, cohesive fracture at a tensile strain of 16 %, making it the weakest points prone to failure. The theoretical tensile strength of the diamond(100)/Al4C3(003)-C terminal interface is about 2.5 times that of the diamond(111)/Al(111) interface. Our work unveils the underlying crystal orientation-dependent growth of Al4C3 and the fracture mechanism of diamond/Al by first-principles calculations and experiments.

Comparative Study on the Liquid Metal Embrittlement Susceptibility of the High-Si Advanced High-Strength Steel with EG and GA Zn Coatings

The Zn-coated high-Si advanced high-strength steel (AHSS) tends to suffer Zn-assisted liquid metal embrittlement (LME) during the resistance spot welding (RSW) process. In this study, the LME behaviors of electrogalvanized (EG) and galvannealed (GA) high-Si steels were comparatively investigated. The maximum lengths of the LME cracks at the shoulder and center of the spot weld were approximately 366.6 μm and 1486.5 μm, respectively, for the EG yet 137.0 μm and 1533.3 μm, respectively, for the GA high-Si steels. Additionally, all EG and GA welded joints were etched to measure the nugget size. It was found that the increased welding current could aggravate the formation tendency of the LME cracks for both the EG and GA high-Si steels. Furthermore, the statistical results revealed that the electrogalvanized high-Si AHSS exhibited a relatively higher LME susceptibility than the galvannealed high-Si AHSS. It was deemed that the internal oxidation produced during the annealing before the Zn coating was the crucial factor that led to the difference in the LME susceptibilities for the EG and GA high-Si steels.

Impact of acidic and alkaline conditions on Staphylococcus aureus and Acinetobacter baumannii interactions and their biofilms.

Bacterial biofilms pose significant challenges due to their association with antibiotic resistance, metabolic adaptation, and survival under harsh conditions. Among notable pathogens forming biofilms, Staphylococcus aureus and Acinetobacter baumannii are concerning pathogens in nosocomial settings. However, their behaviour under acidic (pH 4.5) and alkaline (pH10.5) conditions, especially in co-culture setups, remains insufficiently understood. This study investigates these aspects, by examining growth rates, biofilm formation, pH shifts, phenotypic analysis, and gene expression profiles. The results showed A. baumannii exhibited reduced growth and biofilm formation at pH 4.5, while S. aureus showed slow growth and low biofilm formation at pH10.5 in mono-cultures. S. aureus leaned towards an acidic pH (6-6.5), whereas A. baumannii shifted towards an alkaline pH (8-9). In co-culture environments, growth rates and biofilm formation increased across all pH conditions, converging towards a neutral pH over time. Phenotypic motility assays indicated that A. baumannii exhibited greater motility in alkaline conditions, while S. aureus showed increased staphyloxanthin production under acidic conditions. Gene expression analyses revealed that the fibronectin-binding protein A (FnbA) and N-acetylglucosaminyl-transferase (icaA) genes, responsible for initial attachment during biofilm formation, were highly expressed in acidic co-culture condition but poorly expressed in alkaline condition. In A. baumannii, the outer membrane protein A (OmpA) gene associated with adhesion and virulence, was upregulated in co-culture. TheLuxR gene involved in quorum sensing was upregulated in acidic conditions and poorly expressed at pH 10.5. This study elucidates the metabolic adaptability and biofilm formation tendencies of S. aureus towards acidic conditions and A. baumannii towards alkaline conditions, providing insights for better management of biofilm-related infections.

Предпосылки создания отраслевых индустриальных парков в Тульско-Новомосковской агломерации

The tendencies of the industrial parks formation in the Russian agglomerations are considers in the article. The branch and territorial features of industrial parks foundation in the Tula region are determined on basis of the experience study of the special economic zone (SEZ) «Uzlovaya». The positive influence of the manufacturing SEZ on the branch clusters in agglomerations is confirmed.

An in situ combustion carbon deposit diagnostic instrument based on Raman microscopy.

Carbon deposit of the aero-engine combustor, resulting from incomplete combustion and fuel pyrolysis, can cause nozzle blockage, fuel consumption increase, power decrease, and even flight unsafety. In this work, an in situ combustion carbon deposit diagnostic instrument is developed to reveal the crystalline structure and the changes under real combustion conditions. The instrument integrates the in situ microscopic Raman technique and the combustion system. The burner is characterized by a sloping tip, making it possible to observe the coke from the side view. The burner is installed to the optical positioning stage by a specially made adapter so that the relative location is fixed and it is possible to observe the carbon deposit from the ignition. The carbon deposit of acetylene/air diffusion jet flame was studied. A 50× objective lens was used to collect the Raman scattering signal of carbon deposits continuously 30s after ignition. A five-band model was used to fit the Raman spectra. The time-resolved information was calculated, including the normalized total area, area proportion, peak ratio, and crystalline size. The results show that the carbon deposit of acetylene flames with different velocities presents different tendencies of formation and degree of graphitization, which is attributed to the influence of temperature and flow. The performance of this system is evaluated quantitatively. The signal-to-noise ratio of Raman spectra of carbon deposits ranges from 6.4 to 28.9. This work provides an in situ method to analyze the dynamic change of carbon deposit on the burner, and further work is needed to reveal the mechanism.

Effects of surface-active elements on wettability and interfacial reaction between DD5 superalloy and Al2O3-based ceramic shell

The study investigates the effects of oxygen-sulfur content, holding temperature, and time on the wettability and interfacial reactions between DD5 superalloy and Al2O3-based ceramic shells through non-in-situ sessile drop experiments. Lowering the oxygen-sulfur content in the DD5 master alloy, as well as reducing the holding temperature and time, leads to an increase in the wetting angle and a mitigation of interfacial reactions. Improved wettability promotes interfacial reactions, while intensified interfacial reactions further spread the alloy melt, enhancing its wettability. The main products of the interfacial reaction between the DD5 alloy and Al2O3-based ceramic shells are Al2O3 and Si, with the process being influenced by the presence of Al. When the oxygen-sulfur content is controlled within 6 ppmw, the wettability will undergo a characteristic transformation, resulting in a sharp increase in the wetting angle. It demonstrates that the ultra-pure DD5 master alloy plays a crucial role in reducing wettability and interfacial reaction, as well as slowing down the tendency of the hetero-crystal formation. Therefore, it is of great engineering significance to further reduce the content of oxygen-sulfur impurity elements in DD5 superalloy.

Effect of branching in the alkyl chain of diglycolamide on the sequestration of tetravalent actinides: solvent extraction and theoretical studies.

DGA (diglycolamide) ligands show a different extraction behavior of trivalent metal ions by changing the branching alkyl chain length as well as the branching at the methylene position. There are no studies of these factors on the extraction efficiency of these DGA derivatives for the extraction of tetravalent actinides. We have evaluated four different DGA derivatives for the extraction of Np, Pu, and Th from molecular diluents. The n-butyl derivative shows enhanced extraction efficiency and branching gives rise to a reduction in the extraction efficiency of tetravalent ions. The distribution ratios are higher in pure octanol than in a mixture of 30% octanol and 70% n-dodecane. This behavior is in marked difference to that of the extraction of trivalent ions where the addition of an alcohol generally decreases the distribution ratio of trivalent ions due to the ligand-modifier intercation, poor aggregation or micelle formation tendency of DGAs in polar solvents. This suggests that micelle-mediated extraction may not be the dominating factor for the extraction of tetravalent metal ions. Slope analysis suggests the involvement of only two DGA molecules in the extracted species suggesting no/poor possibility of micelle formation in the present system. The higher extraction in pure octanol may be due to a better solubility of the extracted complexes in this polar medium compared to the mixture of octanol and n-dodecane. The water and acid uptake, the back extraction, and the radiation stability of the solvent systems were also investigated. DFT studies were performed to get a better insight into the extraction and complexation of the different DGA solvent systems.

Erythrophagocytosis-induced ferroptosis contributes to pulmonary microvascular thrombosis and thrombotic vascular remodeling in pulmonary arterial hypertension

BackgroundWhether primary or just as a complication from the progression of pulmonary arterial hypertension (PAH), thrombosis seems to be an important player in this condition. The crosstalk between red blood cells (RBCs) and pulmonary microvascular endothelial cells (PMVECs) and their role in PAH remain undefined. ObjectivesThe goals of this study were to assess the role of RBC–PMVEC interaction in microvascular thrombosis and thrombotic vascular remodeling under hypoxic conditions. MethodsWe established an in vitro hypoxic coincubation model of RBC and PMVEC as well as a hypoxic mouse model. We investigated erythrophagocytosis (EP), ferroptosis, thrombosis tendency, and pulmonary hemodynamics in experimental PAH. ResultsIncreased EP in PMVEC triggered ferroptosis, enhanced procoagulant activity, and exacerbated vessel remodeling under hypoxic conditions. In the PAH mouse model induced by chronic hypoxia, EP-induced ferroptosis followed by upregulated TMEM16F led to a high tendency of thrombus formation and thrombotic vascular remodeling. Inhibition of ferroptosis or silencing of TMEM16F could alleviate hypercoagulable phenotype, reverse right ventricular systolic pressure, right ventricular hypertrophy index, and remodeling of pulmonary vessels. ConclusionThese results illustrate the pathogenic RBC–PMVEC interactions in PAH. Inhibition EP, ferroptosis, or TMEM16F could be a novel therapeutic target to prevent PAH development and thrombotic complications.

A bioswitchable delivery system for microRNA therapeutics based on a tetrahedral DNA nanostructure.

As microRNAs (miRNA) regulate almost all physiopathological activities in the human body, miRNA therapeutics that deliver miRNA regulators have attracted considerable attention in the field of nucleic acid drug development. The use of tetrahedral DNA nanostructures to deliver miRNA regulators is promising because of their simple fabrication, enhanced cell entry, effective tissue penetration, biocompatibility and functional editability. This protocol extension builds on our previous protocol for the use of tetrahedral DNA nanostructures and was designed to establish an updated bioswitchable delivery system (BDS) for achieving controlled cargo loading and release. A ribonuclease H-sensitive sequence is designed as a bioswitchable apparatus for the targeted release of the miRNA regulator. The functional sequence of the miRNA regulator and minimal secondary structure formation tendency during annealing are two key points in cargo design. We provide two BDS design strategies; BDS-A comprises an intact DNA tetrahedron with the RNA cargo hanging outside, offering the merits of lower cost, simplicity, and more direct structural design. In the BDS-B design, the RNA regulators are embedded into the DNA tetrahedron, which is beneficial for dermal tissue permeation applications. Following sequence design in Oligo 7 and Tiamat, the BDS assembly is completed and then ribonuclease H achieves controlled release of the miRNA regulator by triggering the bioswitchable apparatus. This is verified via polyacrylamide and agarose gel electrophoresis or fluorophore modifications. Both BDSs show promising cellular membrane permeability, tissue permeability and target inhibition in vitro and in vivo. The assembly and characterization of the BDS can be completed in 4 d, and the validation time for biostability and biological applications will depend on the specific use.

Drilling performance of Al-Ni eutectic alloy with scandium addition

Al-Ni eutectic alloys are an alternative alloy for high-temperature applications because of their excellent thermal stability of the Al3Ni eutectic fibers. Since the matrix of eutectic Al-Ni is weak, adding Sc to the alloy (Al-6Ni-0.4Sc) is able to increase its strength and hardness. This study is to investigate the machinability of Al-6Ni-0.4Sc alloy compared to Al-6Ni alloy through a drilling process. The results revealed that the Al-6Ni-0.4Sc alloy required less power, torque, and thrust force in the drilling process than Al-6Ni, despite having higher strength and hardness. The average specific energy for the drilling of Al-6Ni-0.4Sc alloy was 1.011 W s/mm3. This was 12.77% less than the value for Al-6Ni alloy. The chip velocity in the drilling of the alloy with Sc addition was twice that of the alloy without Sc, implying low heat accumulation in the cutting tool, less tendency for built-up edge formation, and a low wear rate on the drill’s rake face when drilling Al-6Ni-0.4Sc alloy.

Uncovering all possible dislocation locks in face-centered cubic materials

Dislocation reactions and locks play an important role in the plastic deformation and mechanical behavior of crystalline materials. Various types of dislocation locks in face-centered cubic (FCC) materials have been reported in the literature pertaining to material-specific molecular-dynamic simulations and high-resolution transmission electron microscopy observations. However, it is unknown how many dislocation locks are possible, and how immobile all the dislocation locks are, with respect to each other. Here we present a discrete mathematics-based approach to reveal all possible dislocation locks in the FCC crystal structure. Totally eight types of dislocation locks are uncovered, resulting from all possible reactions of mobile/glissile (namely, perfect and Shockley partial) dislocations with (a) non-coplanar Burgers vectors which reside on two slip planes intersecting at both obtuse and acute angles and (b) coplanar Burgers vectors. We redefine the degree of dislocation lock immobility based on misorientations between non-close-packed lock planes and close-packed {111} slip planes. The subsequently derived sequences for the dislocation lock immobility and formation tendency are rationalized by the reported experimental and dislocation-dynamics simulation results.

Dual-Salt aqueous electrolyte for enhancing Charge-Storage properties of VO2 polymorphic cathodes for Zn-Ion batteries

Three VO2 polymorphs, namely monoclinic VO2 (B), monoclinic VO2 (M), and tetragonal VO2 (A), are synthesized, and their microstructures and electrochemical properties are studied for application in Zn-ion batteries (ZIBs). A cost-effective ZnSO4-based aqueous electrolyte with various concentrations (3 − 7 m) of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) additive is developed. The optimal ZnSO4/LiTFSI ratio in the electrolyte for superior Zn//VO2 battery properties is examined. The coordination structures of various electrolytes are investigated using wide-angle X-ray scattering. The incorporation of LiTFSI impairs the hydrogen-bonded network of H2O molecules and causes solvated-TFSI and TFSI‧‧‧TFSI structures to form, altering the electrolyte properties (such as electrochemical stability window, ionic conductivity, and Zn(OH)2)3(ZnSO4)·xH2O byproduct formation tendency). It is found that an excessive LiTFSI concentration leads to the formation of ion aggregates in the electrolyte and thus deterioration of electrode specific capacity and rate capability. Operando transmission X-ray microscopy observations confirm the high dimensional stability of the VO2 cathode during charging and discharging; the length variation of the VO2 (B) rods is approximately 10 %. The electrolyte composition also affects the Zn2+/Zn redox behavior at the anode side. The incorporation of LiTFSI into the electrolyte affects the Zn plating/stripping Coulombic efficiency, morphology of the deposited Zn, dead Zn amount, and anode cycle life. The constructed Zn//VO2 (B) cell with 1 m ZnSO4/5 m LiTFSI dual-salt electrolyte shows 90 % capacity retention after 1000 cycles. The proposed electrode material and electrolyte composition have great potential for applications in high-performance and high-stability rechargeable ZIBs.

Chemical Speciation and Preservation of Phosphorus in Sediments along the Southern Coast of Zhoushan Island

This study investigated the distribution of sedimentary phosphorus (P) species along an area of a rapid current at the southern coast of Zhoushan Island. The objective of this study was to improve the understanding of P cycling in a zone of rapid water cycling. Results showed that the average percentage of each P form to total P (TP) was in the following order: apatite P (Ca-P; 52%) was found in the most abundant, followed by organic P (OP; 16%), exchangeable-P (Ex-P; 14%), detrital P (De-P; 11%), and iron-bound P (Fe-P; 7%). Ca-P showed a trend of an increasing concentration from a location at the west (ZS1 has mean Ca-P = 45.6 mg kg−1) toward the east (ZS2 has mean Ca-P = 82.69 mg kg−1) and south-east (ZS3 has mean Ca-P = 82.17 mg kg−1); De-P also increased from 15.12 mg kg−1 at ZS1 to 22.53 mg kg−1 at ZS2 and 27.45 mg kg−1 at ZS3, but the three bioavailable P species, OP, Ex-P, and Fe-P, decreased from the west toward the east of the coastal area. Results along the cores showed the occurrences of sediment P adsorption and release throughout the time span from the 1930s to the present, with an overall trend of decreasing Ca-P and TP from the bottom to surface sediments. There was a tendency of Ca-P formation at the expense of Ex-P and OP release during transport and organic matter decomposition. The likely impact of climate change in the coastal zone would be an increased temperature resulting in elevated organic matter decomposition and P release.

An Advanced Solvent for the Caustic-Side Solvent Extraction of Cesium from Nuclear Waste: Comparing Lipophilic Guanidines for Improved Hydrolytic Stability

ABSTRACT An advanced solvent has been developed for application in the extraction of cesium from alkaline nuclear waste. Four lipophilic guanidines have been compared to arrive at a more hydrolysis-resistant suppressor component of the solvent. Plans call for deployment of the Next-Generation Caustic Side-Solvent Extraction (NG-CSSX) process at industrial scale for separation of radioactive Cs-137 from the legacy salt waste stored at the US Department of Energy Savannah River Site (SRS). In the solvent used in NG-CSSX, an alkyl guanidine “suppressor” component facilitates efficient stripping of the loaded cesium from the solvent. However, as typical of guanidine compounds, the suppressor previously used in the NG-CSSX solvent, N,N‘,N’’-tri(3,7-dimethyloctyl)guanidine (TiDG), suffers from hydrolytic degradation under process conditions. Recently, the sterically hindered alkyl guanidine N,N’-dicyclohexyl-N’’-(10-nonadecyl)guanidine (DCNDG) has been found to offer 8 to 44 times greater hydrolysis resistance than TiDG. Here, the process performance characteristics of the NG-CSSX solvent incorporating DCNDG are determined in comparison with TiDG and two other guanidine suppressors. The solvent has been adjusted in density to accommodate use in the SRS Salt Waste Processing Facility and tested under aggressive bench-scale conditions intended to increase plant throughput. Experiments include the effect of ageing at normal and off-normal temperatures of the distribution of Cs+ through the NG-CSSX process, the fate and effects of guanidine degradation products, suppressor capacity, coalescence times for aqueous-solvent dispersions, tendency for emulsification, third-phase formation, and degree of protonation of the guanidine in stripping. While the chosen structures of the four compared guanidines mainly effect differences in stability, subtle differences in other system properties such as emulsion formation and suppressor capacity provide insight into the function of this important solvent component. In comparison with TiDG and two other guanidines, DCNDG provides greatly increased stability while not compromising the excellent functional properties of the NG-CSSX solvent.