Cold Nitrogen Research Articles

Preparation of Graphite Electrode Waste/Natural Carbon Black/Polyvinylidene Fluoride Composites Using Liquid Nitrogen Cold Quenching

Graphite and carbon are attractive carbon-carbon (C/C) composite materials for applications due to exceptional electrical transport properties and high charge mobility. The liquid nitrogen cold quenching method could increase porous, hardness, and electrical conductivity. Composite material graphite electrode waste/natural carbon black / polyvinylidene fluoride (GEW/NCB/PVDF) was made by mixing 70wt% GEW, 10wt% NCB and 20 wt% PVDF with non-solvent method by means ball mill for 900 minutes. The mixture was then moulded using hot press machine at pressure of 5.5 MPa, temperature of 150°C for 60 minutes with dimension of 5 × 5 × 0.3 cm3. After that, put it off into liquid nitrogen quickly. The conclusion is preparation of GEW/NCB/PVDF composite by using liquid nitrogen cold quenching could increase porous, hardness, and electrical conductivity. However, this composite shows decrease in density.

Past and present aspects of Italian plasma chemistry

The linking between the initial activities of the Rome–Bari group to their present activities is discussed in different fields of plasma chemical-physics. Several topics are presented including (1) plasma catalysis, (2) the interaction of alumina particles with thermal plasmas and its linking with the thermodynamics and transport properties of plasmas, and (3) non-equilibrium vibrational kinetics coupled with the Boltzmann equation for the electron energy distribution functions (eedf) in aerospace and cold plasma applications. The old activities in plasma catalysis pointed out the importance of atomic species affecting catalytic reactions opening also to the possibility of non-equilibrium vibrational distributions on the chemisorbed ad-atoms. This last aspect is discussed also taking into account recent developments. The study of the interaction of alumina particles with thermal plasmas was rationalized assuming that the step controlling the reaction could be the heat transfer plasma-particle. The model used a simplified fluid dynamic approach with the insertion of accurate values of thermodynamic and transport properties of thermal plasmas. This kind of activity can be considered precursor on the intense work in the field with particular attention on the importance of electronic excited states in affecting thermodynamics and transport of plasmas. Moreover, the plasma-particle interactions can be recovered to a given extent in the modern aspects of hypersonics in the boundary layer of re-entering vehicles as well as in the nozzle flow expansion. In both cases, we underline the existence of vibrational distributions (vdf) far from the Boltzmann behaviour and rates presenting an anti-Arrhenius trend as a function of the inverse of gas temperature. Concerning the non-equilibrium vibrational kinetics, we discuss two case studies. The first one deals with the behaviour of cold nitrogen plasmas pointing out the role of superelastic vibrational and electronic collisions on vdf and eedf. In this case, we discuss also the same case study comparing the results obtained by a complete set of electron molecule cross-sections acting on the whole vibrational ladder with the corresponding ones which consider transitions starting and arriving to the vibrational ground state of the molecule. The last case study concerns the dissociation kinetics of CO2 in cold plasmas, a topic largely studied in the past to emphasize the role of vibrational excitation in CO2 destruction. Recent results obtained using a sophisticated model based on the coupling of Boltzmann equation for the eedf and a state-to-state vibrational kinetics of the asymmetric ladder of CO2 are reported. The interplay between dissociation process by direct electron impact collision and by heavy particle collisions with vibrationally excited CO2 molecules is discussed.

Enhanced bonding strength of heat-treated wood using a cold atmospheric-pressure nitrogen plasma jet

In this work, the bonding strength enhancement of heat-treated wood using a cold atmospheric-pressure nitrogen plasma jet for several lengths of treatment time was investigated. The enhancement of bonding strength was assessed by measurement of the contact angle of aqueous adhesive and water borne finish along with determination of compressive shear strength of wood samples bonded with an aqueous adhesive and pull-off strength of a water borne finish coating on wood samples. Additionally, the elemental composition and crystallinity index of the heat-treated wood surface were characterized using X-ray photoelectron spectroscopy and X-ray diffraction. As expected, the measurements demonstrated that contact angle decreased after atmospheric-pressure nitrogen plasma jet treatment, and the optimal treatment time was 100 s. X-ray photoelectron spectroscopy shows that hydrophilic groups such as C=O, OH, and COOH appeared on the surface of the HW. The atmospheric-pressure nitrogen plasma jet treatment had a positive effect on the crystallinity of heat-treated wood because of a slight degradation of hemicelluloses. Increasing the bonding strength of heat-treated wood is beneficial for broadening the fields of its applications.

Characterisation of Silicon Photomultipliers for liquid xenon detectors

Silicon Photomultipliers (SiPMs) are considered as a solid-state sensor alternative to photomultiplier tubes in experiments using liquid xenon (LXe) as a radiation detection medium. The main requirements are single-photon detection of the vacuum ultraviolet scintillation light from LXe at 178 nm with high resolution and detection efficiency and low noise rates. Further requirements for dark matter and double beta decay searches are ultra-low radioactivity levels of all the components including the substrates and cold electronics. Here we describe our characterisation of Hamamatsu 6×6 mm2 SiPMs in the temperature range 110–300 K in nitrogen gas, as well as long-term measurements in cold nitrogen gas at 172 K and liquid xenon at 185 K. After we introduce the experimental setups, the data acquisition schemes and analysis methods, we show the single-photon response, the gain versus bias voltage, as well as the dark and correlated noise rates. We demonstrate the long-term stability at cryogenic temperatures, and conclude that SiPM arrays are promising candidates for photosensor arrays in liquid xenon detectors. Furthermore, we study the radioactivity of the raw SiPM materials with gamma spectrometry and inductively coupled plasma mass spectrometry and conclude that SiPMs are suitable for use in low-background experiments.

Physiological and transcriptomic insights into the cold adaptation mechanism of a novel heterotrophic nitrifying and aerobic denitrifying-like bacterium Pseudomonas indoloxydans YY-1

Development of low-temperature biological nitrogen removal processes is of scientific and engineering importance. Cold-adapted heterotrophic nitrifying and aerobic denitrifying (HNAD) bacteria have attracted increasing interest. However, the nitrogen metabolism and cold adaption mechanisms of HNAD bacteria remain unclear.In this article, a novel cold-adapted HNAD-capable bacterium, Pseudomonas indoloxydans YY-1, was isolated. Analyses of draft whole-genome features indicated that strain YY-1 was capable of complete dissimilatory nitrate reduction, ammonium assimilation, and cyanate decomposition. The gene cluster of napABCDE and gene norR, which encode for the periplasmic nitrate reductase and nitric oxide reductase transcription regulator, were identified in the YY-1 genome. Adenosine triphosphate levels increased fivefold, and polysaccharide content significantly rose in the extracellular polymeric substances of strain YY-1 when temperature decreased from 25 °C to 5 °C. Comparative transcriptional profiles of the strain grown at 25 °C and 10 °C revealed that the genes involved in tricarboxylic acid cycle, cytochrome reductase, transhydrogenase, and adenosine triphosphate synthesis were overexpressed, whereas the genes that encod for nicotinamide adenine dinucleotide dehydrogenase, cytochrome reductase, and the functional proteins of nitrate assimilation were downregulated. For ammonium assimilation of strain YY-1 at 10 °C, transcriptional data revealed the overexpression of glutamate dehydrogenase and glutamate synthase genes. This study highlights the potential nitrogen metabolic diversity of HNAD bacteria and expands the understanding of physiological and transcriptional strategies of cold adaption of those bacteria.

Quantitative proteomics of psychotrophic diazotroph in response to nitrogen deficiency and cold stress

Effective protocols and novel biomarkers are the need of this hour to screen potential cold adapted diazotrophs for sustainable mountain agricultural plans. LC-MS/MS based gel less quantitative proteomics was employed to investigate the metabolic response of Himalayan cold adapted diazotroph Pseudomonas palleroniana N26 (JN055435) for nitrogen deficiency and cold stress. More than 5000 proteins were identified, and 125 of them showed significant difference with a 2-fold or greater change (p < .05) between normal and stress conditions, including 29 up-regulated proteins and 35 down-regulated proteins. Expression of nifA, nifL, nifH, nifB, nifD, and nifK during N2 fixing conditions reveals that nitrogenase system was successfully activated. Further, 8% of the upregulated proteins showed similarity with uncharacterized proteins of several nitrogen fixing genera which suggests their in-depth investigation. Additionally, as per earlier studies, cowN was differentially expressed under nitrogen fixing conditions; thereby, confirming its potential to be a potent biomarker for monitoring the nitrogen fixation in cold niches. Biological significanceUnderstanding of nitrogenase expression and regulation is essential to employ potential diazotrophs under diverse ecological niches to achieve agricultural as well as environmental sustainability. The molecular mechanisms of cold adapted diazotrophy are still unaddressed. In this scenario, present study, besides characterizing diazotrophic proteins, is helpful in identifying the protein(s) or a biomarker viz. CowN to facilitate the monitoring of nitrogen fixation in cold niches. To the best of our knowledge, this is the first gel-less quantitative free-living diazotrophic proteome study using label free mass spectrometry having high mass accuracy in both MS and MS/MS scans. It enriches the diazotrophic proteome database and will complement the other “omics” technologies for improved crop protection and sustainability strategies.

New technology for cutting ferrous metal with diamond tools

In recent years, cutting objects for diamond tools have gradually expanded from non-ferrous metal and optical glass to ferrous metal materials. Moreover, the requirements of accuracy have continued to increase. To reduce the tool wear of diamond-cutting ferrous metals, a real-time adjustment method using nitrogen cold plasma was proposed. Atmospheric flexible cold plasma jet (AFCPJ) was developed to restrain diamond tool wear by reducing the chemical affinity on the tool–workpiece interface and by adjusting the complex thermal condition in the cutting zone. To obtain better cooling, lubrication, and modification effects, an ultrasonic elliptical vibration cutting device with separation characteristic was designed to promote the entry of the active particles in AFCPJ into the too–workpiece interface. Unlike dry cutting, diamond cutting assisted by cold plasm and ultrasonic elliptic vibration can help reduce the diffusion wear of carbon elements in a diamond tool to workpieces and chips and also effectively reduce the cutting temperature and the surface roughness of the workpiece. Results show that the AFCPJ can significantly restrain the tool wear of diamond-cutting ferrous metals. In addition, the diamond tool wear achieves the best restraining effect when cold plasma and ultrasonic elliptical vibration work together.

Seed storage of Brazilian cacti species in different threat categories

AbstractCactaceae is considered the fifth most endangered taxonomic group. In light of this, the aim of this study was to evaluate the efficiency of different low‐temperature storage techniques in maintaining the viability of seeds of cacti in different threat categories. Seeds of six cacti taxa were stored in a cold chamber (8°C), a freezer (−5°C), in liquid nitrogen (−196°C) and at room temperature (25–27°C) for a period of 0, 1, 3, 6, 9 and 13 months. At each evaluation interval we removed a seed sample for each taxon studied, which was distributed into four repetitions of 25 seeds maintained at room temperature under 12‐h light/dark photoperiods. We evaluated the germinability, mean germination time and synchronization index. Most of the studied taxa presented germinability of above 50%, which was influenced by time and by storage temperatures. Also, most taxa stored at room temperature presented a significant reduction in germinability, whereas almost all taxa showed maintenance of the seed viability when stored in a cold chamber, a freezer or liquid nitrogen. This response can be justified by the reduction of the seed metabolism and the degradation of the reserve compounds of the seeds while at lower temperatures. Our results indicate that storage at low temperatures is an effective method for the conservation of cacti seeds and can be used for the formation of artificial seed banks of threatened cacti species.

Embedding Co3O4 nanoparticles into graphene nanoscrolls as anode for lithium ion batteries with superior capacity and outstanding cycling stability

Co3O4 is a promising high-performance anode for lithium ion batteries (LIBs), but suffers from unsatisfied cyclability originating duo to low electrical conductivity and large volume expansion during charge and discharge process. Herein, we successfully constructed the Co3O4 nanoparticles embedded into graphene nanoscrolls (GNSs) as advanced anode for high-performance LIBs with large capacity and exceptional cyclability. The one-dimensional (1D) Co3O4/GNSs were synthesized via liquid nitrogen cold quenching of large-size graphene oxide nanosheets and sodium citrate (SC) modified Co3O4 nanoparticles, followed by freeze drying and annealing at 400 °C for 2 h in nitrogen atmosphere. Benefiting from the interconnected porous network constructed by 1D Co3O4/GNSs for fast electron transfer and rapid ion diffusion, and wrinkled graphene shell for significantly alleviating the huge volume expansion of Co3O4 during lithiation and delithiation. The resultant Co3O4/GNSs exhibited ultrahigh reversible capacity of 1200 mAh g−1 at 0.1 C, outperforming most reported Co3O4 anodes. Moreover, they showed high rate capability of 600 mAh g−1 at 5 C, and outstanding cycling stability with a high capacity retention of 90% after 500 cycles. Therefore, this developed strategy could be extended as an universal and scalable approach for intergrating various metal oxide materials into GNSs for energy storage and conversion applications.

Feasibility study of a turbocharger rotor supported by air foil bearings with diameter of 17 mm focusing on rotordynamic performance

This paper presents the feasibility study of an oil-free turbocharger with journal bearing diameter of 17 mm. Rotordynamic performance of a turbocharger rotor, supported by two identical bump-type foil journal bearings and a pair of foil thrust bearings, is predicted and tested. High-pressure cold nitrogen is adopted to drive the turbocharger rotor. In rotordynamic analysis, the critical speeds and logarithmic decrement of the turbocharger rotor are predicted by employing the finite element method, in which the stiffness and damping coefficients of foil journal bearings and aerodynamic cross-coupled stiffness of the turbine are taken into account. Compared with experimental results, the accuracy of the prediction for rotordynamic analysis is verified for 7.82% marginal error of the critical speed. During the experiment, three foil journal bearings with different nominal clearances are manufactured and tested. The maximum stable operating speed reaches 105,000 r/min for this 17-mm-diameter oil-free turbocharger rotor system. Test results indicate the nominal clearance has a negative influence on threshold speed of sub-synchronous motions. When the nominal clearance is relatively small, the foil journal bearing could not lift off due to a large starting torque, while sub-synchronous motions would emerge under a large nominal clearance because of the reduced stiffness and damping coefficients of foil journal bearings.

A setup for fast cooling of liquids in sealed containers

We present a simple layout of a fast cooling system for liquids in sealed containers utilizing the large temperature gradients of cold nitrogen gas. Our system is optimized for about 20 cylindrical containers of 500 cm3, but the setup allows for simple up- and down-scaling as well as the use of arbitrary containers. We have characterized the cooling performance of our system experimentally for temperatures of the liquid in the range from room temperature down to the freezing point at ≈−2 ºC. With our system we achieve container cooling times as low as 3 min, a significant reduction if compared to cooling times with common methods in the range of 8 to 40 min. Modeling of the cooling process proves that convection within the liquid is crucial for quick heat transfer. For the cases studied here, the most important factor limiting the cooling rate is the thermal conductivity of the container material.

A quantitative speed of sound database for multi-component jet mixing at high pressure

This study is the first to provide a comprehensive speed of sound database for multi-component jet mixing at high pressure. It serves as a unique reference for numerical simulations of mixture preparation processes in future liquid rocket engines and internal combustion engines. We performed quantitative speed of sound measurements in jet mixing zones for five configurations with well-defined experimental conditions. The database covers three different injectant fluids (two alkanes and a fluoroketone) that were brought beyond their critical temperature and pressure prior to injection and discharged into cold nitrogen at supercritical pressure (with respect to the pure injectant properties). Here, we chose the conditions such that subsonic jets were obtained and re-condensation due to cooling of the injected fluid was prevented. Hence, we provide speed of sound data for single-phase jet mixing for three different binary systems. Quantitative data are presented along the jet centerline with sufficiently high spatial resolution to properly resolve the axial decay. In addition, two radial profiles at a position close to the nozzle allow for an assessment of the transversal mixing characteristics. The experimental speed of sound data show consistent trends, which corroborate that mixture effects are correctly resolved in the measurement.

Laser ignition of a multi-injector LOX/methane combustor

This paper reports the results of a test campaign of a laser-ignited combustion chamber with 15 shear coaxial injectors for the propellant combination LOX/methane. 259 ignition tests were performed for sea-level conditions. The igniter based on a monolithic ceramic laser system was directly attached to the combustion chamber and delivered 20 pulses with individual pulse energies of $${33.2 \pm 0.8 \,\text{ mJ }}$$ at 1064 nm wavelength and 2.3 ns FWHM pulse length. The applicability, reliability, and reusability of this ignition technology are demonstrated and the associated challenges during the start-up process induced by the oxygen two-phase flow are formulated. The ignition quality and pressure dynamics are evaluated using 14 dynamic pressure sensors distributed both azimuthally and axially along the combustion chamber wall. The influence of test sequencing on the ignition process is briefly discussed and the relevance of the injection timing of the propellants for the ignition process is described. The flame anchoring and stabilization process, as monitored using an optical probe system close to the injector faceplate connected to photomultiplier elements, is presented. For some of the ignition tests, non-uniform anchoring was detected with no influence onto the anchoring at steady-state conditions. The non-uniform anchoring can be explained by the inhomogeneous, transient injection of the two-phase flow of oxygen across the faceplate. This characteristic is verified by liquid nitrogen cold flow tests that were recorded by high-speed imaging. We conclude that by adapting the ignition sequence, laser ignition by optical breakdown of the propellants within the shear layer of a coaxial shear injector is a reliable ignition technology for LOX/methane combustors without significant over-pressure levels.

Mixing characterization of highly underexpanded fluid jets with real gas expansion

We report a comprehensive speed of sound database for multi-component mixing of underexpanded fuel jets with real gas expansion. The paper presents several reference test cases with well-defined experimental conditions providing quantitative data for validation of computational simulations. Two injectant fluids, fundamentally different with respect to their critical properties, are brought to supercritical state and discharged into cold nitrogen at different pressures. The database features a wide range of nozzle pressure ratios covering the regimes that are generally classified as highly and extremely highly underexpanded jets. Further variation is introduced by investigating different injection temperatures. Measurements are obtained along the centerline at different axial positions. In addition, an adiabatic mixing model based on non-ideal thermodynamic mixture properties is used to extract mixture compositions from the experimental speed of sound data. The concentration data obtained are complemented by existing experimental data and represented by an empirical fit.

Sequential effect of phages and cold nitrogen plasma against Escherichia coli O157:H7 biofilms on different vegetables

Escherichia coli O157:H7 (E. coli O157:H7) is one of the most common pathogens in fresh vegetables and fruits, and most of the diseases produced by E. coli O157:H7 are associated with biofilms. Cold nitrogen plasma (CNP) is a cold sterilization technique which has no residue. However to completely eliminate the biofilm on the surface of vegetables the processing power and time of CNP have to be enhanced, which will impact on the quality of fruits and vegetables. Thus the sequential treatment of CNP and phage techniques was engineered in this study. Compared to treatment performed separately, sequential treatment not only had more mild treatment conditions as 400W CNP treatment for 2min and 5% phage treatment for 30min, but also exhibited more remarkable effect on eradicating E. coli O157:H7 biofilms in vitro and on vegetables. The population of E. coli O157:H7 was approximately reduced by 2logCFU/cm2 after individual treatment of 5% phages for 30min or 500W CNP for 3min. While the sequential treatment of CNP (400W, 2min) and phages (5%, 30min) reduced the E. coli O157:H7 viable count in biofilm by 5.71logCFU/cm2. Therefore, the sequential treatment holds a great promise to improve the current treatment systems of bacterial contamination on different vegetable surfaces.

Dome C ultracarbonaceous Antarctic micrometeorites

Context.UltraCarbonaceous Antarctic MicroMeteorites (UCAMMs) represent a small fraction of interplanetary dust particles reaching the Earth’s surface and contain large amounts of an organic component not found elsewhere. They are most probably sampling a contribution from the outer regions of the solar system to the local interplanetary dust particle (IDP) flux.Aims.We characterize UCAMMs composition focusing on the organic matter, and compare the results to the insoluble organic matter (IOM) from primitive meteorites, IDPs, and the Earth.Methods.We acquired synchrotron infrared microspectroscopy (μFTIR) andμRaman spectra of eight UCAMMs from the Concordia/CSNSM collection, as well as N/C atomic ratios determined with an electron microprobe.Results.The spectra are dominated by an organic component with a low aliphatic CH versus aromatic C=C ratio, and a higher nitrogen fraction and lower oxygen fraction compared to carbonaceous chondrites and IDPs. The UCAMMs carbonyl absorption band is in agreement with a ketone or aldehyde functional group. Some of the IR and Raman spectra show a C≡N band corresponding to a nitrile. The absorption band profile from 1400 to 1100 cm-1is compatible with the presence of C-N bondings in the carbonaceous network, and is spectrally different from that reported in meteorite IOM. We confirm that the silicate-to-carbon content in UCAMMs is well below that reported in IDPs and meteorites. Together with the high nitrogen abundance relative to carbon building the organic matter matrix, the most likely scenario for the formation of UCAMMs occurs via physicochemical mechanisms taking place in a cold nitrogen rich environment, like the surface of icy parent bodies in the outer solar system. The composition of UCAMMs provides an additional hint of the presence of a heliocentric positive gradient in the C/Si and N/C abundance ratios in the solar system protoplanetary disc evolution.

The Effects of Nitrogen Content and Cold Rolling Reduction on the Mechanical Properties of New 420-series Stainless Steel Strip having a Mesh As-Welded Structure by the Electroslag Cladding

The Effects of Nitrogen Content and Cold Rolling Reduction on the Mechanical Properties of New 420-series Stainless Steel Strip having a Mesh As-Welded Structure by the Electroslag Cladding

Plasma-treated poly(ethylene oxide) nanofibers containing tea tree oil/beta-cyclodextrin inclusion complex for antibacterial packaging

This work describes the effect of cold nitrogen plasma to enhance the antibacterial activity of poly(ethylene oxide) (PEO) nanofibers containing antibacterial agent. Beta-cyclodextrin (β-CD) and tea tree oil (TTO) were used as a host-guest to form water-soluble inclusion complex. The encapsulation efficiency of TTO in inclusion complex could reach 73.23% at 60°C. As antibacterial agent, the inclusion complex was encapsulated into PEO matrix by electrospun. After plasma treatment, the release efficiency of antibacterial agent from PEO nanofibers was improved. As a result, the antibacterial activity of PEO nanofibers was enhanced accordingly. The plasma-treated nanofiber membranes achieved the highest antibacterial activity against Escherichia coli O157:H7, which was tested on the beef for 7d, with inhibition efficiently of 99.99% whether at 4°C or 12°C. The plasma-treated PEO nanofiber membranes containing TTO/β-CD inclusion complex (TTO/β-CD-IC) can prolong the shelf-life of beef, suggesting it has potential application in active food packaging.

Resolution of the carbon contamination problem in ion irradiation experiments

Abstract The widely experienced problem of carbon uptake in samples during ion irradiation was systematically investigated to identify the source of carbon and to develop mitigation techniques. Possible sources of carbon included carbon ions or neutrals incorporated into the ion beam, hydrocarbons in the vacuum system, and carbon species on the sample and fixture surfaces. Secondary ion mass spectrometry, atom probe tomography, elastic backscattering spectrometry, and principally, nuclear reaction analysis, were used to profile carbon in a variety of substrates prior to and following irradiation with Fe 2+ ions at high temperature. Ion irradiation of high purity Si and Ni, and also of alloy 800H coated with a thin film of alumina eliminated the ion beam as the source of carbon. Hydrocarbons in the vacuum and/or on the sample and fixtures was the source of the carbon that became incorporated into the samples during irradiation. Plasma cleaning of the sample and sample stage, and incorporation of a liquid nitrogen cold trap both individually and especially in combination, completely eliminated the uptake of carbon during heavy ion irradiation. While less convenient, coating the sample with a thin film of alumina was also effective in eliminating carbon incorporation.

Tool wear behavior of thermal-mechanical effect for milling Ti-6Al-4V alloy in cryogenic

In order to make clear the effect of heat-force on tool wear for milling Ti-6Al-4V alloy in cryogenic cooling. The thermal-mechanical calculation models were established. Compared with conventional cutting, the thermal-mechanical effect rules and thermal action characteristics were analyzed in cryogenic cooling. As well as the cryogenic cooling milling method was executed for a series of processing experiments. The influence of heat-force on chip morphology and surface quality are researched. Meanwhile, the regular tool wear and mechanism were discussed. The results show that the measurement data and change tendency of milling forces are similar to the calculated data; the model is basically effective. Besides, when the cutting micro-unit is kept away from the tool nose, the tool-workpiece contact temperature and cutting force are all slow change compared with conventional cutting in cryogenic. Because of the tool-workpiece interaction squeezing action, the plastic-brittle deformation is obtained under the effect of liquid nitrogen cold quenching. Furthermore, the built-up edge in tool nose is not formed in cryogenic with unobvious thermal softening effect, so the friction effect of hard material is reduced. As a result, it improves obviously the workpiece machining quality and tool life, even as the stable wear range of tool has been transformed from 0.075–0.2 to 0.05–0.26 mm. Therefore, the thermal- mechanical effect influences tool wear, and controlling heat-force is evident, effective for improving tool life through cryogenic cooling.