Plasma Technique Research Articles

Dynamic of mode transition in air surface micro-discharge plasma: reactive species in confined space

Flexible surface micro-discharge plasma is a non-thermal plasma technique used for treating wounds in a painless way, with significant efficacy for chronic or hard-to-heal wounds. In this study, a confined space was designed to simulate wound conditions, with gelatin used to simulate wound tissue. The distinction between open and confined spaces was explored, and the effects of temperature, humidity, discharge power and the gap size within the confined space on the plasma characteristics were analyzed. It was found that temperature, humidity and discharge power are important factors that affect the concentration distribution of active components and the mode transition between ozone and nitrogen oxides. Compared to open space, the concentration of ozone in confined space was relatively lower, which facilitated the formation of nitrogen oxides. In open space, the discharge was dominated by ozone initially. As the temperature, humidity and discharge power increased, nitrogen oxides in the gas-phase products were gradually detected. In confined space, nitrogen oxides can be detected at an early stage and at much higher concentrations than ozone concentration. Furthermore, as the gap of the confined space decreased, the concentration of ozone was observed to decrease while that of nitrate increased, and the rate of this concentration change was further accelerated at higher temperature and higher power. It was shown that ozone concentration decreased from 0.11 to 0.03 μmol and the nitrate concentration increased from 20.5 to 24.5 μmol when the spacing in the confined space was reduced from 5 to 1 mm, the temperature of the external discharge was controlled at 40 °C, and the discharge power was 12 W. In summary, this study reveals the formation and transformation mechanisms of active substances in air surface micro-discharge plasma within confined space, providing foundational data for its medical applications.

Synthesis, Structural Analysis and Investigation of Photoluminescence Properties of Mixed Metal Cation Borates

The compounds synthesized in this study are mixed metal borates with the structure of MMeR(BO3)2 (M=Na+, Me=Sr2+, R=La3+, Ce3+, Nd3+, Sm3+ and Er3+). Solid state method was used for synthesis. Unlike the literature, borates containing three cations were synthesized using acetates of the starting materials. In the structure of borates, alkali and earth metal cations are surrounded by six and nine oxygen atoms, respectively. Rare earth metal cations are surrounded by six oxygen atoms. The complex structure of borates makes them strong candidates for nonlinear optics (NLO) applications. Since boron element (B) is coordinated with three or four oxygen atoms, they not only form planar triangles (BO33−) or tetrahedral (BO44−) but also bond with each other to form various structural units. This structural diversity is suitable for the discovery of new compounds with linear optical and nonlinear optical properties. Among these structural units, BO3 groups have attracted great attention due to their nonlinear optical properties, which are capable of producing moderate birefringence and broad ultraviolet (UV) transparency. Borates that do not contain rare earth metal cations are currently used in nonlinear optical applications to produce high-power visible and ultraviolet light. Due to the importance of borate compounds for industry and research, the aim of the study is to synthesize new types of mixed metal borate compounds and to investigate their structural properties. Powder X-ray diffraction (P-XRD), Fourier transform infrared spectroscopy (FT-IR), Inductively Coupled Plasma (ICP) and Thermal Gravimetric Analysis (TGA) techniques were used for the characterization of the synthesized mixed metal borate structures. Photoluminescence properties were investigated by Photoluminescence (PL) Spectroscopy in the application study.

Doping- and capacitor-less 1T-DRAM cell using reconfigurable feedback mechanism

In this paper, we propose a doping- and capacitor-less 1T-DRAM cell, which achieved virtual doping by leveraging charge plasma and bias-induced electrostatic doping (bias-ED) techniques in a 5 nm-thick intrinsic silicon body, thereby eliminating doping processes. Platinum was in contact with the drain, while aluminum was in contact with the source, enabling virtual doping of the silicon body into ap*-i-n* configuration via the charge-plasma technique. Two coupled polarity gates and one control gate are positioned above the intrinsic channel region. The intrinsic channel region is virtually doped through the bias-ED by applying voltages to the gates, forming potential wells inside the channel. The voltage applied to the two coupled polarity gates determines whether the device operates in thep- orn-channel mode, whereas the control gate governs the flow of charge carriers. Charge carriers are stored and released in the potential wells inside the channel by adjusting the gate, effectively replacing the capacitor. In this device, the placement of polarity gates on either side of the control gate enables the observation of the reconfigurable characteristics. Moreover, the proposed device utilizes a feedback mechanism, enabling excellent memory characteristics such as a high on/off current ratio of ∼109, steep switching behavior of ∼0.2µV dec-1, short write time of 10 ns, long hold retention of over 100 s, and long read retention of over 600 s.

Cold Plasma Treatment Facilitated the Conversion of Lignin-Derived Aldehyde for Pseudomonas putida.

Syringaldehyde derived from lignin is one of the essential intermediates for the production of basic chemicals. However, it was poorly understood for the direct microbial conversion of syringaldehyde. Here, this study tried to use cold plasma technique to enhance syringaldehyde conversion for the bacterium Pseudomonas putida. It illustrated that cell growth and syringaldehyde conversion were separately increased by 1.49 times at 3 h and 1.60 times at 6 h for 35 s, 1.16 and 3.44 times for 140 W, and 1.63 and 4.02 times for 105 Pa for P. putida through single factor assays of cold plasma treatment. To be sure, cell growth and syringaldehyde conversion were enhanced by 1.14 and 5.54 times at 3 h under the optimum parameters (35s, 140 W, and 105Pa) for P. putida. Furthermore, genome re-sequencing further discovered single-nucleotide polymorphisms of P. putida, such as PP_2589 (A428V), PP_5651 (V82F), and PP_0545 (W335R), and thus indicated that the potential genetic changes derived from cold plasma treatment would be responsible for the acceleration of syringaldehyde conversion. This work would provide a robust strain catalyst and the potential candidate mutation sites for genetic manipulation for microbial bioconversion of the value-added and lignin-based biochemicals.

Combination of atmospheric and room temperature plasma and ribosome engineering techniques to enhance the antifungal activity of Bacillus megaterium L2 against Sclerotium rolfsii.

Sclerotium rolfsii is an extremely destructive phytopathogenic fungus that causes significant economic losses. Biocontrol strategies utilizing antagonistic microorganisms present a promising alternative for controlling plant pathogens. Bacillus megaterium L2 has been identified as a potential microbial biocontrol agent in our previous study; however, its efficacy in controlling pathogens has yet to meet current demands. This study aims to enhance the antifungal activity of strain L2 against S. rolfsii R-67 through a two-round mutagenesis strategy and to preliminarily investigate the mutagenesis mechanism of the high antifungal activity mutant. We obtained mutant Dr-77 with the strongest antifungal activity against R-67, and its cell-free supernatant significantly reduced the infection potential of R-67 to Amorphophallus konjac corms, which may be attributed to the antimicrobial compound phenylacetic acid (PAA), and PAA content in Dr-77 (5.78 mg/mL) was 28.90 times higher than original strain L2. This compound exhibited strong antifungal ability against R-67, with a half maximal effective concentration (EC50) value of 0.475 mg/mL, significantly inhibiting mycelial growth and destroying the ultrastructure of R-67 at EC50 value. Notably, PAA also exhibited broad-spectrum antifungal activity against six phytopathogens at EC50 value. Moreover, genome analysis revealed nine different gene mutations, including those involved in PAA biosynthesis, and the activities of prephenate dehydratase (PheA) and phenylacetaldehyde dehydrogenase (ALDH) in PAA biosynthesis pathway were significantly increased. These results suggest that the elevated PAA content is a primary factor contributing to the enhanced antifungal activity of Dr-77, and that this mutagenesis strategy offers valuable guidance for the breeding of functional microbial resources. © 2024 Society of Chemical Industry.

COMPARISON OF THE EFFICACY OF ARTHROCENTESIS WITH AND WITHOUT CONCENTRATED GROWTH FACTOR INJECTIONS IN REDUCING CLINICAL SYMPTOMS IN PATIENTS WITH TEMPOROMANDIBULAR JOINT OSTEOARTHRITIS

There is a significant prevalence of temporomandibular joint (TMJ) disorders, estimated at 34% according to various sources. Given that this condition often leads to a reduced quality of life and disability, there is a pressing need to develop and implement effective treatment methods. Arthrocentesis, along with the injection of pharmacological agents—particularly platelet-rich plasma—into the joint cavity, is a recognized treatment for TMJ osteoarthritis. Recently, a third generation of platelet concentrates has been developed, which is an evolutionary advancement of the platelet-rich plasma technique. This study involved 60 patients, equally divided into control and experimental groups. The control group was treated with arthrocentesis for TMJ osteoarthritis, while the experimental group received arthrocentesis combined with intra-articular injections of concentrated growth factor. The effectiveness of the treatments was evaluated using the visual analogue scale (VAS) for pain and measuring maximum mouth opening. The study results showed a 74.22% reduction in VAS scores in the control group and a 79.87% reduction in the experimental group (p < 0.001). Maximum mouth opening increased by 17.84% in the control group and by 20.53% in the experimental group (p < 0.001). Both treatment methods demonstrated significant clinical efficacy (p < 0.001). In our opinion, the use of arthrocentesis with concentrated growth factor injections for the treatment of TMJ osteoarthritis is clinically justified and more effective than arthrocentesis alone.

Cold Plasma Techniques for Sustainable Material Synthesis and Climate Change Mitigation: A Review

In recent years, the emission of greenhouse gases (GHGs) has increased significantly, contributing to global warming. Among these GHGs, CH4, CO2, and CO are particularly potent contributors. Remediation techniques primarily rely on materials capable of capturing, storing, and converting these gases. Catalytic processes, particularly heterogeneous catalysis, are essential to chemical and petrochemical industries as well as environmental remediation. Due to the growing demand for catalysts, efforts are being made to reduce energy consumption and make technologies more environmentally friendly. Green chemistry emphasizes minimizing the use of hazardous reactants and harmful solvents in chemical processes. Achieving these principles should be paired with processes that reduce time and costs in catalyst preparation while improving their efficiency. Non-thermal plasma (NTP) has been widely used for the preparation of supported metal catalysts. NTP has attracted significant attention for its ability to improve the physicochemical properties of catalysts, enhancing process efficiency through low-temperature operation and shorter processing times. NTP has been applied to various catalyst synthesis techniques, including reduction, oxidation, metal oxide doping, surface etching, coating, alloy formation, surface treatment, and surface cleaning. Plasma-prepared transition-metal catalysts offer advantages over conventionally prepared catalysts due to their unique material properties. These properties enhance catalytic activity by lowering the activation energy barrier, improving stability, and increasing conversion and selectivity compared to untreated samples. This review demonstrates how plasma activation modifies material properties and, based on extensive literature, illustrates its potential to combat climate change by converting CO2, CH4, CO, and other gases, showcasing the benefits of plasma-treated materials and catalysts. A succinct introduction to this review outlines the advantages of plasma-based synthesis and modification over traditional synthesis techniques. The introduction also highlights the various types of plasma and their physical characteristics across different factors. Additionally, this review addresses methods by which materials are synthesized and modified using plasma. The latter section of this review discusses the use of non-thermal plasma for greenhouse gas mitigation, covering applications such as the dry reforming of CH4, CO and CH4 oxidation, CO2 reduction, and other uses of plasma-modified catalysts.

Copper Paste Printed Paper‐Based Dual‐Band Antenna for Wearable Wireless Electronics

AbstractWearable wireless electronics is becoming a significant research area because of the unique features of this technology. Within this field printed antennas are the key electrical component accomplishing the signal transmission and energy harvesting tasks and at the same these antennas need to be lightweight, environmentally friendly, safe to wear, and easy to conform. Currently, the majority of available paper‐based antennas are designed for RFID, sensing, UWB, WLAN, and medical applications, with just a few being utilized in wearable applications, particularly for wireless body area network (WBAN). Furthermore, few studies have been conducted on the usage of printable copper conductive materials and low‐temperature plasma technique for the fabrication of such antennas. This study demonstrates the realization of a dual‐band paper‐based wearable antenna by screen‐printing of a plasma‐sintered conductive copper paste. The copper paste, composed of 51 wt% solid particles, can easily produce desired conductive patterns on photo paper after printing and a subsequent plasma sintering, with a good adhesion. The antenna designed on photopaper operates in the frequency bands of 1.73–2.55 GHz and 7.66–8.89 GHz. Free‐space simulation and measurement results reveal that the antenna exhibits stable radiation performance in the targeted WBAN (2.4–2.4835 GHz) and X uplink (7.9–8.4 GHz) frequency bands, together with low profile, excellent conformality and acceptable SAR values on the body and no electronic waste formed after disposal, making it a competitive candidate for usage in wearable wireless electronics.

Cold plasma irradiation of chitosan: A straight pathway to selective antitumor therapy

Plasma-activated chitosan (PAC) colloids for cancer treatment were obtained by using the cold atmospheric plasma technique. Chitosan solutions were irradiated by plasma ignited in argon gas and in a mixture of argon with nitrogen and oxygen gases in certain ratios. The structural modifications of chitosan and the chemical species generated in plasma were investigated by EPR, LC-MS/MS, XRD, DLS, and TGA methods. The cell viability test showed a selective cytotoxic effect on human breast carcinoma cells (MCF-7), while the human mammary epithelial cells (MCF-10A) were left unharmed. The cytotoxic effect was attributed mainly to chitooligosaccharides, but also to a synergistic effect with other compounds generated in very low concentrations in plasma, such as glyceric acid, ethyl acetate, or tricarballylic acid. The plasma irradiation improved the antioxidant activity and mucoadhesivity, while not affecting the hemocompatibility investigated by a standard hemolysis ex vivo test on mice blood. Moreover, the in vivo biocompatibility investigation at intraperitoneal administration of PAC in mice showed no statistically significant changes in the hematologic, biochemical, and immune system parameters, and no morphologic alterations of the liver and kidney. All these data indicate the cold plasma activation of chitosan as a straight method to produce biocompatible, antitumor systems.

Reverse water-gas shift in a novel spark-coupled dielectric barrier discharge plasma: Effects of electrode structure and gas parameters

The reverse water–gas shift (RWGS) reaction holds promise for producing raw materials used in the synthesis of high-value chemicals. However, the reaction is often hindered by low CO2 conversion rates at atmospheric pressure and low temperatures. To overcome this limitation, this study developed a novel reactor based on strengthened spark-coupled dielectric barrier discharge (SSCDBD) without a catalyst, leveraging local high temperatures to enhance performance. The effects of reactor structure and gas parameters on conversion rate and energy efficiency were systematically investigated. The results indicated that the SSCDBD device notably improved CO2 conversion compared to conventional plasma techniques, such as dielectric barrier discharge (DBD), spark discharge, and spark-coupled dielectric barrier discharge (SCDBD), with respective increases of 1000 %, 12.65 %, and 2.79 %. Notably, varying the length of the auxiliary electrode affects the capacitance of the equivalent capacitor and, consequently, the discharge intensity. Furthermore, Increasing the electrode length from 4 cm to 20 cm improved the CO2 conversion rate from 43.7 % to 59.8 %. Moreover, CO2 conversion was positively correlated with the discharge distance, which also affected the volume of the electric arc. However, distances exceeding 1.2 cm interfered with arc formation. At a CO2:H2 molar ratio of 1:1, with an auxiliary electrode length of 12 cm and a discharge distance of 0.8 cm, the maximum CO2 conversion rate of 66 % was achieved at a total feed flow rate of 100 mL min−1, while maintaining a CO selectivity higher than 99 %. Additionally, with a total feed flow rate of 400 mL min−1, CO2 conversion reached 29 % and energy efficiency peaked at 6.34 %.

Precision micro-particle removal from through-holes via laser-induced plasma shockwaves in additive manufacturing

This study introduces a novel Laser-Induced Plasma (LIP) technique for the non-contact, rapid removal of nano and microparticles from through-holes in Additive Manufacturing (AM) components. This method is crucial for high-value applications, such as medical devices, compact heat exchangers, and aerospace engineering, which require efficient cleaning of intricate parts with holes and channels to address high failure costs. The technique leverages shockwaves generated by LIP to target and clean these complex geometries. The research focuses on two main areas: (i) characterizing the effects of shockwaves in semi-cylindrical channels to understand interactions with complex geometries, and (ii) quantitatively analyzing the removal of Fe-271 microparticles from semi-cylindrical channels of silicon (Si) wafers, selected for their consistent surface properties compared to the rough textures of AM-produced surfaces. Utilizing the experimental set-up Laser-Induced Plasma LIP Cleaning for Additive Manufacturing (LIPCAM), the study demonstrates that complete microparticle removal is achievable up to 20 mm from the plasma source with variable laser pulses. The results indicate that particles larger than 27 μm are entirely removed after a single pulse, and particles larger than 21 μm are removed after 50 pulses. These findings highlight the method's effectiveness in achieving high particle removal efficiency across different distances and particle sizes, thus ensuring thorough decontamination of complex internal structures. The study underscores the potential of this method to enhance the reliability and safety of critical AM builds, making it a viable solution for industries where precision and cleanliness are paramount.

Innovative Atmospheric Plasma Jets for Advanced Nanomaterial Processing

This study presents a comprehensive exploration of atmospheric pressure plasma jets (APPJs) as an innovative method for synthesizing and modifying nanomaterials, offering a versatile and efficient approach to tailoring their properties and functionalities. Unlike traditional low-pressure plasma techniques, APPJs operate at ambient conditions, providing significant advantages in scalability, cost-effectiveness, and environmental sustainability. This review delves into the recent advancements in APPJ technology, including the development of microfluidic configurations that enhance plasma generation and control, leading to improved efficiency, power, and user accessibility. These advancements have opened new possibilities in various fields, such as the development of antimicrobial coatings, advanced drug delivery systems, and high-performance solar cells. The ability of APPJs to facilitate precise surface engineering and targeted material deposition positions them as a transformative technology in nanomaterial processing. Despite their potential, challenges such as scalability and environmental impact must be addressed to realize widespread adoption. This study underscores the promise of APPJs in driving future industrial applications and highlights the need for continued innovation to overcome current limitations and unlock their full potential across multiple sectors.

Facile fabrication of ZnO nanoparticles via non-thermal plasma technique and their anti-corrosive effects on X60 API 5L steel in 1M HCl solution

This work aims to explore the efficiency of ZnO nanoparticles synthesized via the non-thermal gliding arc discharge-assisted plasma (NT-GAD) technique for inhibiting the corrosion of X60 API 5L steel in a 1M HCl environment. The XRD pattern revealed that the ZnO nanoparticles exhibit hexagonal wurtzite structure with average particle size of ∼24 nm. UV–visible spectroscopy analysis revealed an absorption peak centering at 365 nm, corresponding to an energy band gap of 3.29 eV. SEM and TEM analysis revealed that the nanoparticles exhibit an agglomerated and irregular morphology. The corrosion inhibition of ZnO NPs was investigated via the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests (PDP), while varying both concentration and temperature. The results revealed that the increase in inhibitor concentration resulted in a higher activity at ambient temperature, with an optimal efficiency of 93 % at a concentration of 100 mg/L. However, the increase in temperature remarkably reduced the inhibition efficiency, suggesting a physisorption behavior of ZnO NPs onto the steel surface. AFM and FE-SEM analysis confirmed the formation of a protective layer on the X60 API 5L steel surface. This study emphasizes the significant potential of ZnO NPs synthesized via the NT-GAD assisted plasma technique as corrosion inhibitor for X60 API 5L carbon steel in 1M HCl corrosive media.

Mitigation of polycyclic aromatic hydrocarbons (PAHs) in roasted beef patties by cold plasma treatment and products quality evaluation

The cold plasma (CP) technique was applied to alleviate the contamination of polycyclic aromatic hydrocarbon (PAH) in this investigation. Two different CP treatments methods were implemented in the production of beef patties, to investigate their inhibition and degradation capacity on PAHs. With 5 different cooking oils and fats addition, the inhibition mechanism of in-package cold plasma (ICP) pretreatment was explored from the aspect of raw patties fatty acids composition variation. The results of principal component analysis showed that the first two principal components accounted for more than 80 % of the total variation in the original data, indicating that the content of saturated fatty acids was significantly positively correlated with the formation of PAHs. ICP pretreatment inhibited the formation of PAHs by changing the composition of fatty acids, which showed that the total amount of polyunsaturated fatty acids decreased and the total amount of monounsaturated fatty acids increased. Sensory discrimination tests demonstrated there were discernable differences between 2 CP treated samples and the controls, utilization of the ICP pretreatment in meat products processing was expected to achieve satisfying eating quality. In conclusion, CP treatment degraded PAHs through stepwise ring-opening oxidation in 2 reported pathways, the toxicity of PAHs contaminated products was alleviated after CP treatment.

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Benzonitrile (BZN) and carbon tetrachloride (CCl4) are versatile solvents used as a precursor for the synthesis of many products. As multi-usage molecules, these compounds may be involved in sustainable chemistry processes such as the cold plasma techniques for which the generated electrons are known to be responsible for reactions. Therefore, it is desirable to explore the interaction of low energy electrons with the co-compounds in the gas phase. The production of chlorine and cyanine anions, initiated by the electron collision with CCl4 and BZN, respectively, undergo nucleophilic substitution SN2 reaction with the precursors molecules for the synthesis of chlorobenzene and tricholoacetonitrile. The mechanism of fragmentation of benzonitrile and the synthesis reactions are rationalized by DFT calculations. The yield of the cyanine anion produced from the ion reaction increases with the temperature of the admixture gas, probed in the 25-100 °C temperature range. The present work may contribute to a potential process for the production of chlorobenzene for instance via (cold) plasma techniques.

Inactivation effect and mechanism of Pediastrum by in-liquid pulsed discharge plasma

The issue of eutrophication in river and lake ecosystems is escalating, resulting in harmful algal blooms that adversely impact the aquatic environment. Thus, it is crucial to develop new technology that can effectively inactivate algae without causing secondary pollution to the water body. This work uses in-liquid pulsed discharge plasma technique to inactivate Pediastrum. The research investigates variations in inactivation ratios, chlorophyll-a concentrations, and the inactivation mechanisms under different discharge conditions. The results indicate that the optimal inactivation effect is achieved at a peak voltage of 30 kV, an electrode spacing of 7 mm, and a discharge duration of 20 min, resulting in a 90 % inactivation ratio and a reduction in chlorophyll-a concentration from 1.31 mg/L to 0.63 mg/L (on the fourth day of re-culturing). The discharge process generates strong shock waves, ultraviolet lights, and significant amounts of oxidizing agents, such as· O, H2O2, O3, leading to cell damage, cell wall disruption, and enzyme activity reduction, thereby achieving effective inactivation.

Evaluation of cold plasma treatment technology in biosynthesized silver nanoparticles encapsulated with chitosan by Aliinostoc persicum SA14 against HepG-2

Hepatocellular carcinoma (HCC) is the commonest cancer and the third most common cause of cancer-related mortality. The combination of cold atmospheric plasma (CAP) and nanoparticles is a promising treatment for hepatocellular carcinoma cancers. In the present study, activated water was prepared using the cold atmospheric plasma technique (JET and PAW), and then the biosynthesis ability of silver nanoparticles by the cyanobacterium Aliinostoc persicum SA14 was measured after cultivation in the culture medium containing activated water at 5, 15, and 20 min. After the encapsulation of nanoparticles with chitosan and UV–visible spectroscopy analysis, the characterization of AgNPs, including FTIR analysis. X-ray diffraction, particle size and zeta potential, SEM, TEM, as well as cytotoxicity assays against HepG-2 cell lines, were performed. The comparison of the absorption spectra of silver oxide nanoparticles prepared by the boiling-dender method at concentrations and different times showed that the production of silver nanoparticles was confirmed for all three samples based on the amount of absorption obtained. The outcomes of field emission scanning electron microscopy at all magnifications exhibited that spherical nanoparticles are scattered on the surface of the polymer matrix. Furthermore, the FT-IR spectrum and XRD crystallography confirmed the success of chitosan's production of microcoated silver nanoparticles. The results of the cytotoxicity test against HepG-2 cell lines showed that with increasing concentrations of silver nanoparticles, the survival frequency of cancer cells declined significantly. In conclusion, the tests confirmed that the silver nanoparticles produced by cyanobacteria act as both a stabilizing and reducing agent. The results indicated that CAP decreases nanoparticle size, decreases surface charge distribution of AgNP, and induces uptake, aggregation, and enhanced cytotoxicity against HepG-2 in vitro. The chitosan-AgNPs with cold plasma could have potential applications in the food, agricultural, and pharmaceutical industries.

The effect of polysaccharide type on dielectric barrier discharge (DBD) plasma glycosylation of sodium caseinate-part I: Physicochemical, structural and thermal properties

This study aimed to investigate the impact of polysaccharide type on the physicochemical, structural, and thermal properties of dielectric barrier discharge (DBD) plasma glycosylated sodium caseinate (SC). The polysaccharides Quince seed gum (QSG), carboxymethyl cellulose (CMC), and maltodextrin (MD) were mixed with SC and treated with DBD plasma at 18 kV for 10 min. The grafting degree, electrophoresis pattern, FTIR, XRD, carbonyl, sulfhydryl, and di-tyrosine content, FE-SEM, color, and thermal properties of SC and its polysaccharide mixtures before and after plasma treatment were analyzed. Results showed that the SC-QSG conjugate had the highest glycation degree and color change after plasma treatment. The SC-CMC and SC-QSG conjugates exhibited disappearance of distinct SC bands in electrophoresis pattern compared to SC. Also, significant changes in functional group and crystallinity were occurred in SC-CMC conjugate. Plasma treatment caused oxidation of SC, but the presence of polysaccharides offered protection against oxidation. The microstructure of SC was altered by mixing with polysaccharides and exposure to plasma. Also, the mixtures indicated higher thermal stability after plasma treatment. Results confirmed that the generation of protein-polysaccharide conjugates through DBD plasma technique was depended on with SC-MD conjugate unable to form through this method.

Thermal and Thermomechanical Analysis of Amorphous Metals: A Compact Review

Metallic glasses are amorphous metals that are supercooled to a frozen, glassy state and lack long-range order, in contrast to conventional metal structures. The lack of a well-ordered structure largely contributes to the unique properties exhibited by these materials. However, their synthesis and processability are defined and thereby constrained by a plethora of thermal and mechanical parameters. Therefore, their broader utilization in the scientific field and particularly in the related industry is somewhat hindered by the limitations related to preparing them in higher amounts. This may be overcome by changing the approach of metal glass formation to a bottom-up approach by utilizing solid-state plasma techniques, such as spark plasma ablation. Another important aspect of amorphous metals, inherently related to their non-equilibrium metastable nature, is the necessity to understand their thermal transformations, which requires unconventional thermal analysis methods. Therefore, this minute review aims to highlight the most important conceptual parameters behind configuring and performing conventional and advanced thermal analysis techniques. The importance of calorimetry methods (differential and fast scanning calorimetry) for the determination of key thermal properties (critical cooling rate, glass-forming ability, heat capacity, relaxation, and rejuvenation) is underscored. Moreover, the contributions of thermomechanical analysis and in situ temperature-dependent structural analysis are also mentioned. Namely, all of the mentioned temperature-dependent mechanical and structural analyses may give rise to the discovery of new glass systems with low critical cooling rates.

Operando facet control of hydrophobic iron nitride nano-coral for surface protection via field-modulated plasma strategy

A facile facet reconfiguration has been considered as an essential issue for nitride coating in promoting surface protection behaviour. Compared to physical-chemical methods to achieve heterogeneous coating, plasma nitridation strategy is regarded as a favourable technique to in-situ deliver nitride protecting layer, but it is difficult to precisely control surface framework through plasma technique due to complicated interaction environment. To simply achieve nitride coating with favourable surface protection behaviour, we design a novel auxiliary insulator-confined plasma system to directly achieve hydrophobic iron nitride nano-coral (hFeNC) with desirable corrosion- and wear-resistant properties by controlling surface heating process during plasma nitridation. The resultant hFeNC nano-framework delivers corrosion rate of 1.2 mpy, 4- and 9-times lower than that of solid iron nitride film (sFeN) via normal plasma and initial Fe in NaCl condition, respectively. Operando plasma diagnostics along with numerical simulation further confirm the effect of surface heating on typical plasma parameters as well as the iron nitride nano-frameworks, indicating surface heating as the key factor responsible for the favourable surface protection coating.