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Nitrogen fixation is crucial for plants as it is utilized for the biosynthesis of almost all biomolecules. Most of our atmosphere consists of nitrogen, but plants cannot straightforwardly assimilate this from the air, and natural nitrogen fixation is inadequate to meet the extreme necessities of global nutrition. In this study, nitrogen fixation in water was achieved by an AC-driven non-thermal atmospheric pressure nitrogen plasma jet. In addition, Mg, Al, or Zn was immersed in the water, which neutralized the plasma-treated water and increased the rate of nitrogen reduction to ammonia due to the additional hydrogen generated by the reaction between the plasma-generated acid and metal. The effect of the plasma-activated water, with and without metal ions, on germination and growth in corn plants (Zea Mays) was investigated. The germination rate was found to be higher with plasma-treated water and more efficient in the presence of metal ions. Stem lengths and germination rates were significantly increased with respect to those produced by DI water irrigation. The plants responded to the abundance of nitrogen by producing intensely green leaves because of their increased chlorophyll and protein contents. Based on this report, non-thermal plasma reactors could be used to substantially enhance seed germination and seedling growth.

Recently, Fe-Mn-based alloys have been increasingly catching the attention of the scientific community, because of their tunable and outstanding mechanical properties, and suitable degradation behavior for biomedical applications. In spite of these assets, their corrosion rate (CR) is, in general, too low to satisfy the requirements that need to be met for cardiovascular device applications, such as stents. In fact, the CR is not always the same for all of the degradation stages of the material, and in addition, a finely tuned release rate, especially during the first steps of the corrosion pattern, is often demanded. In this work, a resorbable bimodal multi-phase alloy Fe-3Mn-1Ag was designed by mechanical alloying and spark plasma sintering (SPS) to accelerate the corrosion rate. The presence of several phases, for example α-Fe, α-Mn, γ-FeMn and Ag, provided the material with excellent mechanical properties (tensile strength UTS = 722 MPa, tensile strain A = 38%) and a higher corrosion rate (CR = 3.2 ± 0.2 mm/year). However, higher corrosion rates, associated with an increased release of degradation elements, could also raise toxicity concerns, especially at the beginning of the corrosion pattern. In this study, The focus of the present work was the control of the CR by surface modification, with nitrogen plasma immersion ion implantation (N-PIII) treatment that was applied to mechanically polished (MP) samples. This plasma treatment (PT) improved the corrosion resistance of the material, assessed by static degradation immersion tests (SDITs), especially during the first degradation stages. Twenty-eight days later, the degradation rate reached the same value of the MP condition. Nitrogen compounds on the surface of the substrate played an important role in the corrosion mechanism and corrosion product formation. The degradation analysis was carried out also by potentiodynamic tests in modified Hanks’ balanced salt solution (MHBSS), and Dulbecco’s phosphate buffered saline solution (DPBSS). The corrosion rate was higher in MHBSS for both conditions. However, there was no significant difference between the corrosion rate of the PT in DPBSS (CR = 1.9 ± 0.6 mm/year) and in MHBSS (CR = 2 ± 1.4 mm/year). The cell viability was assessed with human vein endothelial cells (HUVECs) via an indirect metabolic activity test (MTT assay). Due to the lower ion release of the PT condition, the cell viability increased significantly. Thus, nitrogen implantation can control the in vitro corrosion rate starting from the very first stage of the implantation, improving cell viability.

Diamond film with micron-scale grains was prepared on silicon substrate by microwave plasma chemical vapor deposition (MPCVD) system. Then, MPCVD equipment was still used to change the experimental conditions, and only nitrogen was used as the gas source, so as to conduct nitrogen plasma treatment on the deposited diamond film. The effects of different treatment time on the structure, morphology and hydrophilicity of diamond films were investigated under the same nitrogen plasma treatment conditions. The results showed that with the increase of nitrogen plasma treatment time, the surface defect density of diamond grains becomes higher and higher, the concentration of nitrogen and sp 2 C=C composition gradually increase, the hydrophilicity of the corresponding diamond film and deionized water becomes better first (the contact angle between deionized water and diamond film decreases from 97° to 44°), and then, it becomes slightly worse (the contact angle between deionized water and diamond film increases from 44° to 49°). It shows that nitrogen plasma treatment can effectively improve the hydrophilicity of diamond film, and the experimental results are explained reasonably.

Purpose The purpose of this paper is to generate nitrogen-containing groups in the cotton fabric surface via low-temperature nitrogen plasma as an eco-friendly physical/zero-effluent process. This was done for rendering cotton dye-able with Acid Blue 284, which in fact does not have any direct affinity to fix on it. Design/methodology/approach Dyeing characteristics of the samples such as color strength (K/S), fastness properties to light, rubbing and perspiration and durability, as well as tensile strength, elongation at break, whiteness, weight loss and wettability in addition to zeta potential of the dyed samples, were determined and compared with untreated fabric. Confirmation and characterization of the plasma-treated samples via chemical modifications and zeta potential was also studied using Fourier transform infrared spectroscopy (FTIR) and Malvern Zetasizer instrumental analysis. Findings The obtained results of the plasma-treated fabric reflect the following findings: FTIR results indicate the formation of nitrogen-containing groups on cotton fabrics; notable enhancement in the fabric wettability, zeta potential to more positive values and improvement in the dyeability and overall fastness properties of treated cotton fabrics in comparison with untreated fabric; the tensile strength, elongation at break, whiteness and weight % of the plasma treated fabrics are lower than that untreated one; and the durability of the plasma treated fabric decreased with increasing the number of washing cycles. Originality/value The novelty addressed here is rendering cotton fabrics dye-able with acid dye via the creation of new cationic nitrogen-containing groups on their surface via nitrogen plasma treatment as an eco-friendly and efficient tool with a physical/zero-effluent process.

— The effect on the electrical parameters of the SiON/AlGaN/GaN structures of treatment of different durations of low-energy nitrogen plasma is studied. The AlGaN surface is subjected to plasma treatment in the working chamber of the plasma-chemical deposition unit before starting the monosilane to form the SiON film. The changes in the transport properties (conductivity and mobility) of the canal and capacitive properties of the structures are evaluated. It is experimentally shown that such treatment leads to a change in the magnitude of polarization charges both at the insulator-AlGN interface and at the AlGaN/GaN interface. With the use of C–V measurements-in the hysteresis mode, it is shown that at the control voltage ( U > +4 to +5 V), some of the channel electrons are captured in the deep centers at the SiON–AlGaN interface, and with an increase in the duration of exposure to plasma, a sharp increase is observed in the charge Q it , formed by the electronic boundary states. The use of additional treatment with nitrogen plasma transfers work for nitride structures from the D -mode ( V th = –4 V) to the E -mode ( V th = +0.9 V). Using Auger measurements, it was shown that plasma treatment leads to a change in the amount of oxygen in the SiON layer and in the nanoregions of the barrier layer, and with an increase in the duration of plasma exposure, a sharp decrease in the amount of oxygen in these layers is observed. In addition, when using plasma treatment, Ga and Al is redistributed at the AlGaN–GaN interface, i.e., in the channel area. Using Auger measurements near the SiON–AlGaN interface from the side of the insulator, the localization of nitrogen atoms chemically bonded with silicon N(Si) is detected with the formation of a peak at the interface, the size of which increases with the increasing duration of plasma exposure.

We find that nitrogen plasma treatment of micro/nanofibrillated cellulose films increases wettability of the surface by both liquid polar water and nonpolar hexadecane. The increased wetting effect is more pronounced in the case of polar liquid, favouring the use of plasma treated micro/nanofibrillated cellulose films as substrates for a range of inkjet printing including organic-based polar-solvent inks. The films were formed from aqueous suspensions of progressively enzymatic pretreated wood-free cellulose fibres, resulting in increased removal of amorphous species producing novel nanocellulose surfaces displaying increasing crystallinity. The mechanical properties of each film are shown to be highly dependent on the enzymatic pretreatment time. The change in surface chemistry arising from exposure to nitrogen plasma is revealed using X-ray photoelectron spectroscopy. That both polar and dispersive surface energy components become increased, as measured by contact angle, is also linked to an increase in surface roughness. The change in surface free energy is exemplified to favour the trapping of photovoltaic inks.

Dielectric (e.g., kerosene-based oil, deionized water, air) is an essential part of electrical discharge machining (EDM), insulating the workpiece and the electrode and removing the gaseous bubbles and debris. In this paper, ultrasonic vibration (USV) and mist are added to micro-EDM in nitrogen plasma jet (NPJ) to improve machining performance. Water contact angle on the workpiece surface becomes very small due to increased hydrophilicity of the NPJ-treated surface. Experimental results indicate that the discharge distance is about 3.5 times of that without adding mist. Compared to results in NPJ under the same conditions, the material removal rate (MRR) has increased by four when aided with mist and increased more than six times further when aided with USV. Meanwhile, the surface roughness increased. In addition, the tool electrode wear rate (TWR) in NPJ and mist significantly decreased, especially, aided by USV. 3D micro feature has been generated in Brass successfully by the proposed method, and the TWR (-0.04%) is near zero.

Acquiring the optimum growth conditions of Ti-Al-N films, the effects of gas atmosphere, especially the reactive plasma on the material microstructures, and mechanical properties are still a fundamental and important issue. In this study, Ti-Al-N films are reactively deposited by radio frequency inductively coupled plasma ion source (RF-ICPIS) enhanced sputtering system. Different nitrogen gas flow rates in letting into the ion source are adopted to obtain nitrogen plasma densities and alter deposition atmosphere. It is found the nitrogen element contents in the films are quite influenced by the nitrogen plasma density, and the maximum value can reach as high as 67.8% at high gas flow circumstance. XRD spectra and FESEM images indicate that low plasma density is benefit for the film crystallization and dense microstructure. Moreover, the mechanical properties like hardness and tribological performance are mutually enhanced by adjusting the nitrogen atmosphere.

The present study manifests an innovative and green approach to graft metal ion adsorbent, polyethylenimine (PEI), onto an electrospun chitosan (CS)/polycaprolactone (PCL) composite membrane via atmospheric pressure nitrogen plasma grafting polymerization. FTIR absorption peak at around 1690 cm−1 was attributed to the bending vibration of N-H from PEI. Since the plasma exposure time is a dependent factor of –NH bond formation, an increased nitrogen content up to 3.3% was observed with an extensive reaction time under plasma treatment. In addition, N1s spectra showed a clear PEI dominating characteristic at 401.7 eV, which suggested a successful grafting of PEI onto the CS/PCL membrane. According to the EDX analysis, a significant amount of copper ions was detected in PEI-CS/PCL membranes. This study showed that a greener wastewater treatment can be realized with the developed plasma synthesis technology.

Nitrided layers on 6082 aluminum alloy substrates and 1060 aluminum substrates are formed at atmospheric pressure using thermal nitrogen plasma, which only takes seconds to form a millimeter-level layer. The nitrided layers are composed of aluminum nitride (AlN) and aluminum solid solution phases. Microstructures in these nitrided layers can be divided into three regions from bottom to top: the transition region, the dendrite region, and the lamella region. These regions are formed in sequence. The formation mechanisms and processes of the three regions are discussed in detail. Furthermore, we found that Al melt is transported upward through the voids and the capillaries in the AlN structures, and reacts with N plasma in the melt surface. The growth of the AlN structures promotes this transport. With the increase of N2 flow rates from 1 L/min to 7.5 L/min, both the hardness and the wear resistance of the nitrided layers are improved, and the nitrided layer becomes thicker.