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Liquid nitrogen

Liquid nitrogen is the liquefied form of diatomic nitrogen gas (N₂), a colorless, odorless, and inert cryogenic fluid obtained by cooling purified nitrogen to its boiling point of −195.8 °C (77.4 K) at atmospheric pressure.^[1] It has a density of 0.807 g/mL at this temperature and a molecular weight of 28.01 g/mol, with a freezing point of −210 °C (63 K).^[2] Upon warming, it rapidly vaporizes, expanding to approximately 694 times its liquid volume at room temperature and standard pressure, making it an efficient coolant but also posing hazards like asphyxiation in confined spaces due to oxygen displacement.^[3] Liquid nitrogen is primarily produced through the fractional distillation of liquefied air in industrial air separation units, where atmospheric air is compressed, cooled via heat exchangers and expansion turbines, and separated based on the differing boiling points of its components—nitrogen boils at a lower temperature than oxygen.^[3] This cryogenic distillation process yields high-purity nitrogen (typically >99.999%), which is then condensed into liquid form for storage and transport in insulated dewars or tanks.^[2] Its production is energy-intensive but scalable, supporting global demand from sectors requiring ultra-low temperatures. The most notable applications of liquid nitrogen span industry, medicine, and science, leveraging its extreme cold for preservation, processing, and cooling without chemical reactivity. In food processing, it enables rapid flash freezing to preserve texture and nutrients in products like fruits, seafood, and ready meals.^[1] Industrially, it supports cryogenic grinding of heat-sensitive materials, metal hardening, and solvent recovery by condensing vapors at low temperatures.^[4] In medicine, it is used for cryotherapy to treat skin lesions, warts, and tumors by inducing rapid tissue freezing and necrosis, often via sprays or probes using liquid nitrogen at −196 °C to rapidly freeze and destroy targeted tissue.^[5] Scientifically, it preserves biological samples, such as cells and gametes, for cryopreservation and facilitates techniques like NMR spectroscopy and lyophilization for pharmaceuticals.^[4] Despite its utility, handling requires strict safety protocols to prevent cold burns, pressure buildup, and oxygen enrichment in enclosed areas.^[6]

Properties

Physical properties

Liquid nitrogen is the cryogenic liquid form of dinitrogen (N₂), existing as a colorless, odorless fluid at temperatures below its normal boiling point of 77.36 K (−195.79 °C) at 1 atm pressure. Its triple point, where solid, liquid, and gas phases coexist in equilibrium, occurs at 63.15 K (−210.00 °C) and 12.53 kPa.^[7] Key thermodynamic properties of liquid nitrogen at its boiling point include a density of 808 kg/m³, specific heat capacity of 2.04 kJ/kg·K, thermal conductivity of 0.141 W/m·K, dynamic viscosity of 0.16 mPa·s, and latent heat of vaporization of approximately 199 kJ/kg. These values characterize its behavior as a low-viscosity fluid with moderate heat transfer capabilities, essential for cryogenic applications.^[8]^[9] The phase diagram of nitrogen delineates the boundaries between solid, liquid, and vapor phases across temperature and pressure, with the liquid phase stable between the triple point and the critical point at 126.192 K and 3.3958 MPa, beyond which distinct liquid and gas phases cease to exist.^[9] Upon vaporization at 20 °C and atmospheric pressure, liquid nitrogen undergoes a significant volume expansion, with a ratio of 1:694, meaning one volume of liquid produces 694 volumes of gas; this rapid phase change underscores its use in cooling but also poses handling challenges due to pressure buildup. When liquid nitrogen contacts a surface at a temperature well above its boiling point, the Leidenfrost effect occurs, forming an insulating vapor blanket that levitates the liquid and slows evaporation by limiting direct contact. The evaporation rate in this regime is described by the model

\dot{m} = \frac{2 \pi k_g (T_w - T_b) r}{\rho_v h_{fg} \lambda},

where \dot{m} is the mass evaporation rate, k_g is the vapor thermal conductivity, T_w - T_b is the temperature difference between the surface and boiling point, r is the drop radius, \rho_v is the vapor density, h_{fg} is the latent heat of vaporization, and \lambda is a characteristic length scale related to the vapor film thickness.^[10] Exposure to liquid nitrogen induces embrittlement in many metals, reducing their ductility and increasing fracture risk due to diminished atomic mobility at cryogenic temperatures, necessitating the use of low-temperature-compatible alloys in handling equipment. For biological sample storage, it is compatible with cryovials constructed from polypropylene or similar polymers engineered to resist cracking and maintain integrity when immersed in liquid nitrogen.^[11]^[12]

Chemical properties

Liquid nitrogen is composed of diatomic N₂ molecules, where each nitrogen atom is bound to the other via a triple bond in the electronic configuration (σ_{2s})^2 (σ^*{2s})^2 (π{2p})^4 (σ_{2p})^2, resulting in a highly stable structure. This triple bond has a dissociation energy of 941 kJ/mol, one of the highest among diatomic molecules, which contributes to the overall chemical stability of the substance.^[13]^[14] At cryogenic temperatures, liquid nitrogen demonstrates exceptional inertness, exhibiting negligible reactivity with most elements and compounds under standard conditions. This low reactivity stems from the high activation energy required to break the N≡N bond, preventing participation in oxidation reactions or support for combustion below -196°C. Unlike reactive gases, it does not form compounds readily with metals, organics, or other materials at these temperatures, making it ideal for inert atmospheres.^[15]^[14] Liquid nitrogen exhibits low solubility for most non-condensable foreign gases. However, oxygen, being condensable at these temperatures, can enrich in the liquid phase due to its higher boiling point, with commercial samples maintained at low levels (around 20 ppm O₂) to mitigate hazards. Dissolved impurities such as oxygen or hydrocarbons can influence phase behavior, potentially leading to separation or enrichment effects due to differing volatilities, which may alter the cryogenic properties of the mixture.^[16]^[17] Liquid nitrogen maintains stability even under elevated pressures at low temperatures, with molecular decomposition occurring only under extreme conditions, such as temperatures above 2000 K or inputs of high energy like plasma or electrical discharge. In certain mixtures, it can participate in the formation of nitrogen clathrates or solvates, where N₂ molecules are encapsulated within host lattices of other compounds, exhibiting unique cage-like structures. Isotopic variants, such as ¹⁴N₂ (natural abundance ~99.6%) and ¹⁵N₂ (~0.4%), show subtle property differences; for instance, ¹⁵N₂ has a slightly higher boiling point (by ~0.25 K) and density due to its greater molecular mass, affecting fractionation in distillation processes.^[18]^[19]

Production

Industrial production

Liquid nitrogen is primarily produced industrially through cryogenic distillation of atmospheric air, which contains approximately 78% nitrogen by volume. This method relies on either the Linde process or the Claude process to achieve air liquefaction and subsequent separation via fractional distillation. The Linde process utilizes the Joule-Thomson effect for cooling, while the Claude process incorporates an expansion turbine for enhanced efficiency in large-scale operations.^[20]^[21] The production process begins with filtration and compression of ambient air to remove particulates, followed by purification to eliminate water vapor and carbon dioxide, which could otherwise cause blockages. The compressed air is then precooled in heat exchangers and further cooled to liquefaction temperatures, exploiting the Joule-Thomson expansion. In the distillation column, operated at approximately -196°C—the boiling point of nitrogen—the components are separated based on differing boiling points, with nitrogen collected as the overhead product. This fractional distillation yields high-purity liquid nitrogen (>99.99%).^[22]^[20]^[23] Energy requirements for large-scale cryogenic production typically range from 0.3 to 0.5 kWh per kg of liquid nitrogen, reflecting optimizations in compression and heat recovery systems, with yield efficiencies exceeding 99% in modern facilities.^[24] Global production of liquid nitrogen exceeded 10 million tons per year as of 2023, with total industrial nitrogen output over 28 million tons annually, dominated by major producers such as Air Liquide and Linde, which operate large air separation units integrated into industrial complexes.^[25]^[26] Recent advancements focus on hybrid systems combining cryogenic distillation with pressure swing adsorption (PSA) for on-site nitrogen generation, enabling efficient production closer to end-users and reducing emissions from bulk transport. These integrations improve overall sustainability by minimizing energy losses in liquefaction and distribution.^[27]

Laboratory preparation

In laboratory settings, liquid nitrogen is typically produced through the liquefaction of compressed nitrogen gas, which is cooled below its boiling point of 77 K using mechanical refrigeration systems such as pulse-tube cryocoolers. These cryocoolers operate on a closed-cycle principle, compressing and expanding helium gas to achieve the necessary low temperatures without moving parts in the cold section, making them suitable for vibration-sensitive research environments.^[28] Alternatively, liquid helium can be employed as a pre-coolant in hybrid systems to facilitate the initial cooling stage before final condensation.^[29] An alternative approach involves fractional condensation from liquid air, prepared by compressing air and subjecting it to expansion cooling via the Joule-Thomson effect to achieve liquefaction, followed by distillation to isolate nitrogen based on differences in boiling points (nitrogen at 77 K versus oxygen at 90 K).^[30] This method allows for small-scale separation but requires careful control to avoid excessive energy loss during expansion. Essential equipment includes Dewar flasks for containing the cryogenic liquid, vacuum-insulated transfer lines to reduce thermal ingress and prevent boil-off, and analytical tools like gas chromatography for purity verification, often achieving 99.999% nitrogen content by detecting trace impurities.^[31] Typical production yields range from 1 to 10 liters per batch, though contamination risks from residual oxygen or argon—present at about 1% in air—can compromise sample integrity if not mitigated through additional purification steps.^[32] Laboratory production is cost-effective for small volumes at approximately $0.50 to $1.00 per liter, compared to lower industrial bulk rates, enabling on-site generation for experiments without reliance on external suppliers.^[33] Post-preparation, the liquid must be transferred to compatible cryogenic storage to maintain usability, akin to broader handling practices.

Handling and Storage

Equipment requirements

The safe manipulation of liquid nitrogen requires specialized containers designed to minimize heat transfer and prevent rapid boil-off due to its extremely low temperature of -196°C. Dewar flasks, the primary storage vessels, are vacuum-insulated to create a double-walled structure that reduces thermal conduction, with capacities typically ranging from 1 to 100 liters depending on laboratory or industrial needs.^[34]^[35] These flasks are commonly constructed from borosilicate glass for smaller laboratory versions or stainless steel for larger, more durable units, ensuring compatibility with cryogenic conditions while maintaining structural integrity.^[36]^[37] For transferring liquid nitrogen, protective and manipulative tools are essential to avoid direct contact and manage vaporization. Cryogenic gloves, rated for insulation down to -196°C, provide thermal protection during handling, often featuring multi-layered materials like Kevlar and wool for dexterity and safety.^[38] Tongs or cryogenic manipulators allow for safe grasping of samples or vessels without skin exposure, while phase separators attached to transfer hoses direct liquid flow and vent vapor to prevent splashing and uncontrolled boil-off during pouring into open containers.^[39]^[40] Monitoring equipment ensures operational safety by tracking key parameters that could indicate leaks or over-pressurization, exacerbated by liquid nitrogen's expansion ratio of approximately 694:1 upon vaporization. Thermocouples, capable of measuring temperatures from -200°C to ambient, are used to verify storage conditions and detect anomalies in real-time.^[41] Pressure relief valves, integrated into Dewar designs and set to activate at 1.5-2 bar (approximately 22-30 psi), automatically vent excess pressure to avert container rupture.^[42]^[43] Equipment must adhere to compatibility standards emphasizing non-porous surfaces and low-thermal-conductivity materials to prevent leaks and frostbite risks from condensation. Maintenance protocols focus on minimizing losses from inevitable evaporation, which occurs at rates of 1-3% per day in well-insulated Dewars under static conditions. Regular visual inspections for vacuum integrity and loose-fitting, non-pressurized lids are required, with refill protocols involving topping up to full capacity every 1-2 days for active use to sustain cryogenic temperatures.^[44]^[45]^[46]

Storage and transportation practices

Liquid nitrogen is primarily stored in vertical Dewars equipped with neck tubes that reduce heat transfer from the surrounding environment, along with vapor-tight seals to maintain cryogenic conditions. These containers are double-walled vacuum-insulated vessels designed to minimize thermal ingress, and they must be positioned upright to prevent structural stress. Storage sites require well-ventilated areas to mitigate risks of oxygen displacement by evaporating nitrogen gas, and locations should be distant from heat sources, ignition risks, and high-traffic zones to avoid accidental damage.^[47]^[48] Boil-off management is essential to limit losses from inevitable evaporation due to residual heat leak. In standard passive storage using insulated Dewars and tanks, daily boil-off rates are typically under 0.5% for large-scale vessels (over 10,000 liters), achieved through high-performance perlite or multilayer insulation. Monitoring for excessive icing on outer surfaces or pressure anomalies helps detect insulation degradation early.^[49]^[45] Transportation of liquid nitrogen occurs in DOT-compliant cryogenic tanks classified under UN 1977 as a non-flammable, refrigerated liquid (Class 2.2), with specifications ensuring insulation limits evaporation to less than 5% over 24 hours during truck or rail transit. These tanks feature robust outer shells, pressure relief valves, and secure fittings to withstand vibrations and impacts, often transported in dedicated vehicles with spill containment measures. For international or extended hauls, compliance with IMDG or IATA regulations applies for sea or air modes, respectively.^[50]^[51] Regulatory frameworks mandate proper labeling and spill preparedness to ensure safety. In the United States, OSHA standards under 29 CFR 1910.1200 require hazard communication labels identifying "Nitrogen, refrigerated liquid" with pictograms for asphyxiation and cold burn hazards, alongside secondary containment systems like dikes or absorbent materials for potential spills. European Union regulations, including the CLP (Regulation (EC) No 1272/2008), enforce similar GHS-based labeling on containers and storage areas, with provisions for spill diversion to safe drainage or retention bunds as outlined in EIGA guidelines.^[52]^[53] Best practices include rigorous inventory tracking via digital logs or level gauges to monitor usage and detect leaks promptly, coupled with periodic integrity tests for the insulation vacuum, such as annual helium leak detection or pressure rise assessments. These protocols, recommended by industry associations, ensure long-term vessel reliability and compliance with operational standards.^[48]

Applications

Cryogenic and cooling applications

Liquid nitrogen (LN₂), with its boiling point of 77 K, serves as an essential coolant in low-temperature physics and engineering, enabling phenomena and processes that require precise thermal management below ambient temperatures. In cryogenic applications, LN₂ facilitates rapid heat extraction due to its high heat transfer coefficient and phase-change properties, often used in open-loop systems where vaporization absorbs significant latent heat. This makes it ideal for testing materials and devices under controlled low-temperature conditions without the complexity of closed-cycle refrigeration. Its inert nature also ensures minimal chemical interference in sensitive experiments.^[54] In superconductivity research, LN₂ is widely employed to cool high-temperature superconductors (HTS) to their operational regime around 77 K, where they exhibit zero electrical resistance and the Meissner effect. For instance, rare-earth barium copper oxide (REBCO) tapes, a common HTS material, achieve critical temperatures exceeding 77 K when immersed in LN₂, allowing demonstration and characterization of superconducting states in wires and coils for applications like magnets. This cooling method is preferred over liquid helium for HTS due to LN₂'s abundance and lower cost, enabling scalable testing of current-carrying capacities up to tens of thousands of A/cm² at 77 K in moderate magnetic fields. Brookhaven National Laboratory has utilized LN₂-cooled HTS magnets to explore persistent current modes, highlighting their potential in compact, high-field devices.^[55]^[56] In material science, LN₂ enables shrink-fitting of metal components by inducing thermal contraction, allowing precise assembly of interference fits without mechanical force or machining. Metals like steel or aluminum alloys are cooled to approximately -196°C in LN₂ baths, shrinking diameters by 0.1-0.5% to insert into undersized hubs or housings; upon warming, the components expand for a secure, stress-distributed joint. This technique is applied in aerospace and automotive manufacturing, such as fitting turbine shafts, reducing assembly time and avoiding heat-induced distortions from traditional heating methods. For cryogenic grinding of polymers, LN₂ embrittles materials like elastomers or thermoplastics, preventing heat buildup that causes melting, smearing, or molecular degradation during milling. By maintaining temperatures below -150°C, particle sizes as fine as 50 μm are achieved with uniform morphology, preserving material properties for recycling or composite production; this contrasts with ambient grinding, where frictional heat limits fineness and quality.^[57]^[58]^[59]^[60] LN₂ cooling is critical for infrared astronomy detectors, where thermal noise must be suppressed to detect faint signals. Charge-coupled devices (CCDs) for near-infrared observation are housed in LN₂ dewars to reach 77 K, reducing dark current and improving signal-to-noise ratios for wavelengths up to 5 μm. Similarly, bolometers—thermal sensors for mid- to far-infrared—often use LN₂ as an intermediate cooling stage to 77 K before final helium cooling, enhancing sensitivity in ground-based telescopes by minimizing atmospheric and instrumental background. The University of California, Los Angeles, infrared lab employs LN₂ cryostats for CCD mosaics in astronomical imaging, achieving stable operation over extended exposures.^[61]^[62] In quantum computing, LN₂ provides preliminary cooling for dilution refrigerators, which achieve millikelvin temperatures essential for qubit coherence. The system is first pre-cooled to ~77 K using LN₂ to condense helium isotopes and remove heat from structural components, transitioning smoothly to 4He evaporation and then ^3He/^4He dilution for base temperatures below 10 mK. This staged approach minimizes thermal gradients and cryogen consumption in experiments with superconducting qubits or topological insulators. Researchers at the University of Virginia have designed compact dilution units incorporating LN₂ pre-cooling to support scalable quantum processors, ensuring efficient heat rejection from radiation shields.^[63] Performance metrics underscore LN₂'s efficacy in these applications, with cooling rates reaching up to 100 K/s in spray or immersion modes for thin samples, far exceeding air or water cooling. Heat transfer coefficients in boiling LN₂ exceed 10^4 W/m²·K, enabling energy-efficient cooling with low mass flow rates—typically 0.1-1 g/s for 10-100 W loads—due to the fluid's high latent heat of vaporization (199 kJ/kg). In superconductivity tests, this allows quenching rates that preserve metastable states, while in material processing, it supports high-throughput operations with minimal energy input compared to mechanical refrigeration.^[64]^[54]^[65]

Culinary applications

Liquid nitrogen, boiling at -196°C, enables flash-freezing in culinary applications, rapidly solidifying food mixtures to create unique textures without large ice crystal formation. This technique is particularly popular for desserts like nitro ice cream and Dippin' Dots-style beads, where liquid mixtures are poured into the nitrogen and stirred to form small, spherical shapes that retain a creamy consistency upon thawing.^[66]^[67]^[68] In molecular gastronomy, liquid nitrogen aids spherification by instantly freezing droplets of flavored liquids, such as fruit purees, into delicate spheres resembling caviar, while its rapid vaporization produces dramatic smoke effects that enhance presentation in dishes and cocktails. Chefs employ it to freeze foams, transforming airy mixtures into stable, frozen structures that shatter or melt for textural contrast. This rapid cooling minimizes cellular damage, preserving nutritional content like vitamins and enzymes better than traditional freezing methods, as smaller ice crystals cause less disruption to food structures.^[69]^[70]^[71] Culinary use requires specialized equipment, including insulated stainless-steel mixers to contain the nitrogen and protective gear such as cryogenic gloves and face shields to prevent frostbite from spills. The U.S. Food and Drug Administration classifies nitrogen as generally recognized as safe (GRAS) for direct food contact under 21 CFR 184.1540, mandating food-grade purity typically exceeding 99% to ensure absence of contaminants, with the 2017 Food Code advising against adding it immediately before consumption to avoid aspiration risks.^[72]^[73]^[74]^[32] Examples include nitrogen caviar, where alginate solutions are dropped into liquid nitrogen to form burstable pearls, and frozen foams like those in avant-garde desserts that offer a light, crisp bite. These applications have driven market growth in fine dining, with food-grade liquid nitrogen demand increasing at approximately 5-6% annually from 2020 to 2024, fueled by rising interest in innovative textures and presentations.^[75]^[76]^[77]

Medical and biological applications

Liquid nitrogen plays a crucial role in cryopreservation techniques for biological materials, particularly through vitrification protocols that rapidly cool samples to -196°C to form a glass-like state without ice crystal formation. This method is widely used for freezing human sperm, eggs, and embryos, achieving post-thaw survival rates exceeding 90% in optimized procedures, such as 96.9% for vitrified embryos compared to 82.8% with slow freezing.^[78] Vitrification's high cooling rates prevent cellular damage, enabling long-term storage while maintaining fertility potential for assisted reproductive technologies.^[79] In tissue banking, liquid nitrogen facilitates the storage of stem cells and select organs, preserving viability for transplantation and research. Hematopoietic stem cells can be cryopreserved for extended periods, with studies demonstrating maintained viability after up to 34 years in liquid nitrogen.^[80] Corneal tissues, for instance, support storage durations up to 10 years when cryopreserved in appropriate media, allowing for allogeneic lenticular implantation in refractive surgeries.^[81] These practices rely on liquid nitrogen's chemical inertness to avoid sample degradation during extended storage.^[82] Dermatological applications of liquid nitrogen center on cryotherapy for treating benign skin lesions, including warts and actinic keratoses. The procedure involves applying liquid nitrogen via a cotton swab dipped in the cryogen, inducing localized freezing that destroys abnormal tissue through thermal injury and subsequent necrosis.^[83] This targeted approach yields high clearance rates for viral warts, often requiring multiple sessions spaced 2-4 weeks apart, with minimal scarring when performed by trained clinicians.^[84] In biological research, liquid nitrogen enables rapid cooling of samples for high-resolution imaging and structural studies. For cryo-electron microscopy (cryo-EM), vitrification in liquid nitrogen at its boiling point preserves protein complexes in a native hydrated state, supporting atomic-level resolution without radiation damage.^[85] Similarly, in protein crystallization, plunging crystals into liquid nitrogen quenches dynamic states at 77 K, facilitating time-resolved X-ray crystallography to capture intermediate conformations.^[86] Standards for these applications, such as those from the AABB, emphasize rigorous post-thaw viability assays to ensure product quality in cellular therapies. Guidelines recommend assessing cell recovery using trypan blue exclusion or flow cytometry immediately after thawing cryopreserved hematopoietic progenitor cells stored in liquid nitrogen, targeting at least 70-80% viability to confirm engraftment potential.^[87] These protocols, detailed in AABB handbooks, guide thawing rates and monitoring to minimize cryoinjury across medical and research contexts.^[88]

Industrial and other applications

Liquid nitrogen serves as an inert gas in industrial processes to prevent oxidation, moisture ingress, and explosive reactions by purging pipelines and blanketing storage vessels containing reactive chemicals. In oil refineries, it is commonly used to displace oxygen from tanks storing crude oil, refined fuels, and petrochemicals, thereby reducing the risk of combustion during transfer or storage operations.^[89]^[90]^[91] In electronics manufacturing, liquid nitrogen provides cryogenic cooling during semiconductor etching, where low temperatures enhance etch anisotropy, directionality, and selectivity in plasma processes for creating high-aspect-ratio features in silicon and other materials. It is also employed in defect annealing, where rapid quenching in liquid nitrogen after high-temperature treatment minimizes lattice damage from ion implantation, reducing point defects and improving material quality by up to 40% in some cases.^[92]^[93] In agriculture, liquid nitrogen is essential for cryopreserving semen from livestock such as cattle and swine, enabling long-term storage at -196°C to maintain viability for artificial insemination and genetic breeding programs that enhance herd productivity. Additionally, it facilitates the cryopreservation of entomopathogenic nematodes, microscopic worms used in biological pest control; freezing these nematodes in liquid nitrogen achieves near-100% survival rates, allowing their distribution to target soil-dwelling insect pests like grubs without chemical pesticides.^[94]^[95] For entertainment purposes, liquid nitrogen generates low-lying fog effects in theaters and stage productions by rapidly condensing atmospheric moisture upon evaporation, creating dense, ground-hugging haze that enhances visual atmospheres in performances. Compared to dry ice, it produces a more persistent and controllable fog without the risk of carbon dioxide buildup, making it suitable for enclosed spaces when handled with proper ventilation.^[96] Emerging applications include cooling in additive manufacturing, where liquid nitrogen enables high-duty-cycle metal 3D printing by providing in-situ thermal management to dissipate heat from laser or electron beam processes, reducing residual stresses and improving part density in alloys like titanium. In electric vehicle research since 2023, it is used to simulate extreme low-temperature conditions during battery testing, evaluating lithium-ion cell stability and performance down to -40°C to address cold-weather degradation in EV range and charging efficiency.^[97]^[98]

Safety Considerations

Potential hazards

Liquid nitrogen poses several significant hazards primarily due to its extremely low temperature of -196°C (-321°F) and its physical properties as a cryogenic liquid. The primary risks include asphyxiation, cold burns, pressure buildup from vaporization, oxygen enrichment leading to fire intensification, and localized environmental effects from spills.^[99] One of the most critical dangers is asphyxiation, which occurs when liquid nitrogen evaporates and displaces oxygen in enclosed or poorly ventilated spaces, creating an oxygen-deficient atmosphere. Normal air contains approximately 21% oxygen, but concentrations below 19.5% are considered hazardous by OSHA standards, potentially leading to unconsciousness or death without warning. Even small volumes of liquid nitrogen can rapidly reduce oxygen levels, as one liter expands to about 694 liters of gas at room temperature. For example, in August 2025, a liquid nitrogen leak at a food processing plant in Vernon, California, resulted in the deaths of two workers due to asphyxiation (as of November 2025).^[100]^[99]^[101] Direct contact with liquid nitrogen or its cold vapors can cause cold burns, resulting in severe tissue damage akin to frostbite or thermal burns. Exposure, even for seconds, freezes skin and underlying tissues, leading to blistering, necrosis, and potential full-thickness injury that may require medical intervention such as debridement or amputation in extreme cases. The cryogenic nature rapidly forms ice crystals within cells, disrupting cellular structure and causing pain, swelling, and long-term impairment.^[102] Pressure buildup is another hazard, particularly in sealed or inadequately vented containers, where the liquid's expansion upon warming—approximately 700:1 from liquid to gas—can generate extreme internal pressures capable of causing explosive ruptures. This rapid phase change, if unrestricted, turns storage vessels into potential bombs, scattering fragments and cryogenic material.^[99]^[103] Liquid nitrogen can also indirectly contribute to oxygen enrichment, where cold surfaces or spills cause atmospheric oxygen to condense and accumulate, creating localized areas with oxygen levels above 23%. Such enrichment intensifies combustion, lowering ignition temperatures and accelerating fire spread for materials that are normally non-flammable, posing risks of rapid burning or explosions in the presence of fuels.^[2] Environmentally, liquid nitrogen has minimal long-term impact as it is inert and naturally occurring in the atmosphere, but spills lead to rapid evaporation that causes immediate local cooling, potentially freezing nearby surfaces or altering humidity through fog formation. These effects are transient and dissipate as the gas mixes with air, without contributing to pollution or ecological harm.^[104]

Mitigation and precautions

To mitigate risks associated with liquid nitrogen handling, personal protective equipment (PPE) is essential, including cryogenic gloves that comply with EN 511 and are designed for handling liquid nitrogen (not for immersion, as hands should never be immersed to avoid trapped liquid causing injury upon thawing), face shields, and aprons to prevent cold burns and splashes.^[105]^[52]^[106] Engineering controls such as adequate ventilation with 4-6 air changes per hour and oxygen monitors that alarm at 19.5% O₂ levels help prevent asphyxiation in enclosed spaces, while spill kits equipped for cryogenic liquids facilitate rapid containment and evaporation of releases.^[52]^[47] Personnel training is critical, encompassing procedures for detecting and responding to leaks—such as evacuating areas and ventilating without entering oxygen-deficient zones—and first aid protocols that emphasize rewarming cryogenic burns with lukewarm water (around 38–40°C) for 15–30 minutes without rubbing or applying friction to avoid tissue damage.^[47]^[107] Regulatory compliance includes adherence to NFPA 55 for safe storage and handling of cryogenic fluids, which mandates pressure relief devices, secure container placement, and comprehensive emergency response plans, as well as the updated ISO 21009-2:2024 standard for operational requirements of vacuum-insulated cryogenic vessels to ensure pressure management and hazard prevention.^[108]^[109] Best practices further reduce incidents by prohibiting food or drink in proximity to liquid nitrogen to avoid contamination risks and requiring clear labeling with pictograms indicating extreme cold and pressure hazards on all containers and storage areas.^[105]^[6]

History

Discovery and early experiments

Nitrogen gas was first isolated in 1772 by Scottish physician and chemist Daniel Rutherford, who removed oxygen and carbon dioxide from air using heated charcoal and lime, leaving behind the inert gas he called "noxious air."^[110] In the late 1770s, French chemist Antoine Lavoisier further characterized its properties, naming it "azote" (meaning "without life") due to its inability to support combustion or respiration, and demonstrating its role as a major component of the atmosphere alongside oxygen.^[111] Efforts to liquefy nitrogen began in the mid-19th century amid broader investigations into the liquefaction of "permanent gases." In December 1877, French physicist Louis-Paul Cailletet produced the first transient droplets of liquid nitrogen through the sudden expansion of highly compressed gas at low temperatures, a process leveraging the Joule-Thomson cooling effect; around the same time, Swiss physicist Raoul Pictet independently achieved similar results using a countercurrent cooling apparatus.^[112] These experiments yielded only fleeting mists or small quantities that evaporated rapidly, marking initial but unstable liquefaction.^[113] The first stable production of liquid nitrogen occurred on April 15, 1883, by Polish physicists Zygmunt Wróblewski and Karol Olszewski at Jagiellonian University in Kraków, who cooled compressed nitrogen to approximately -195°C using liquid oxygen as a refrigerant in a modified Cailletet apparatus.^[114] This breakthrough allowed for sustained observation of the liquid state, enabling early measurements of its physical properties, such as density (around 0.808 g/cm³ at the boiling point) and boiling point under atmospheric pressure.^[115] Initial experiments focused on the cryogenic effects of liquid nitrogen, including its use to freeze mercury—demonstrating rapid solidification at temperatures far below mercury's freezing point of -39°C—and preliminary biological tests, such as immersing small organisms to study low-temperature tolerance.^[116] Wróblewski detailed these findings in his 1884 publication "Propriétés physiques du gaz azotique à l'état liquide," which reported key thermodynamic data and paved the way for further cryogenic research.^[117]

Commercialization and modern developments

The commercialization of liquid nitrogen began in the late 19th century with Carl von Linde's development of air liquefaction technology. In 1895, Linde patented a continuous process for liquefying air, enabling the separation of nitrogen and oxygen on an industrial scale. This innovation led to the construction of the first commercial air separation plant in 1902, initially focused on oxygen production but quickly adapted for liquid nitrogen as a byproduct, marking the transition from laboratory experiments to viable industrial output.^[118]^[119] World War II significantly accelerated the scale-up of production facilities due to surging demand for oxygen and nitrogen in munitions manufacturing, welding, and explosives. Air separation plants expanded rapidly to meet military needs, with U.S. industrial oxygen sales surpassing 2 billion cubic feet by 1942, driving investments in larger, more efficient units that also yielded substantial liquid nitrogen supplies. Post-war, in the 1950s and 1960s, applications broadened; NASA's Apollo program utilized liquid nitrogen in environmental control systems during missions to support life support functions in microgravity. Concurrently, medical cryogenics advanced, with liquid nitrogen adopted for cryosurgery in 1950 by dermatologist Ray Allington and expanded in 1961 by surgeon Irving Cooper for tissue removal, establishing it as a standard tool in healthcare. A key milestone was its integration into culinary freezing processes in the early 1960s, enabling rapid preservation of food quality in Europe and the U.S.^[120]^[121]^[122] The 1970s energy crises prompted innovations in energy-efficient air separation, with new cryogenic processes reducing power consumption by optimizing distillation and heat recovery, allowing production to scale amid rising costs. In the 2010s, liquid nitrogen found new roles in quantum technologies, cooling nitrogen-vacancy centers in diamond for single-photon emission at 77 K, as demonstrated in 2015 experiments that enabled room-temperature-compatible quantum sensing. Entering the 2020s, sustainability efforts have focused on "green" production, with air separation units powered by renewables and integrated energy storage; for instance, Air Liquide's 2020 investment in a world-scale facility in Europe accommodates intermittent renewable grids, minimizing carbon footprints for nitrogen output used in clean ammonia synthesis.^[123]^[124]^[125]

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Nitrogen - the NIST WebBook
; Thodos, George, Vapor pressures of liquid nitrogen between the triple and critical points, J. ... Boiling point. Tc, Critical temperature. Tfus, Fusion ...<|control11|><|separator|>
[10]
A mathematical model of the Leidenfrost effect on an axisymmetric ...
Jun 18, 2009 · A simple mathematical model is developed for the Leidenfrost effect on an axisymmetric droplet. We first examine the practice of describing large droplets as ...
[11]
Extreme-Engineering Challenge: Cryogenic Toughness in Metals
Nov 13, 2023 · The reason for this embrittlement at cryogenic temperature is that the restriction of the movement of the atoms in the crystal lattice means ...
[12]
[PDF] Cryovial Storage & Liquid Nitrogen - Research How 2
Cryovials should be made of certified polypropylene for use in liquid nitrogen. Explosions are much less likely if vials have internal threads and male caps.
[13]
Bond dissociation energy of N2 measured by state-to-state resolved ...
Jan 4, 2024 · Our analysis revealed a bond dissociation energy for N2 of 78 691.09 ± 0.15 cm−1, which is equivalent to 9.756 452 ± 0.000 02 eV or 941.3542 ± ...State-to-state resolved... · Bond dissociation energy of N2 · IV. SUMMARY
[14]
Nitrogen | N2 | CID 947 - PubChem
In manufacturing of ammonia, nitric acid, nitrates, cyanides, etc; in manufacturing explosives; in filling high-temperature thermometers, incandescent bulbs; to ...
[15]
NITROGEN, REFRIGERATED LIQUID (CRYOGENIC LIQUID)
NITROGEN, REFRIGERATED LIQUID (CRYOGENIC LIQUID) is very unreactive. Nonflammable, noncombustible and nontoxic. Vapors can fill closed spaces and asphyxiate.
[16]
Selecting the Appropriate Nitrogen Gas Purity Level for Your ...
Jul 29, 2025 · Cryogenic liquid nitrogen is extremely pure at roughly 99.998% nitrogen. So, 99.998% nitrogen is stated as 20 ppm oxygen content. Liquid ...
[17]
Nitrogen Gas - Specific Heat vs. Temperature
Specific heat of Nitrogen Gas - N2 - at temperatures ranging 175 - 6000 K. ... At high temperatures above 1500 K dissociation becomes appreciable and ...
[18]
Survey of Cryogenic Nitrogen Thermomechanical Property Data ...
Jul 6, 2020 · The authors employed the use of a colorimeter in their experiments and measured the CP of both 14N2 and 15N2 over the course of several test ...
[19]
Cryogenic Process of Air Separation - IspatGuru
There are several steps in the cryogenic process of air separation. The first step is filtering, compressing and cooling of the incoming air. In most of the ...
[20]
The Claude Process For Liquefaction | Innovation.world
The Claude process improves upon the Hampson-Linde cycle by incorporating an expansion engine or turbine. A portion of the compressed gas does work in an ...
[21]
Air Separation and Liquefaction - Cold Facts Digital
May 29, 2020 · The following flowchart outlines the basic process steps in cryogenic air separation: Air Filtration and Compression. Atmospheric air is ...
[22]
Air Separation - MATHESON
Oxygen purity can exceed 99.5%; nitrogen purity can exceed 99.99%. Argon can be produced only by cryogenic air separation.
[23]
Numerical Analysis of a Liquid Nitrogen (LN2) Engine for Efficient ...
Jun 7, 2021 · A conventional cryogenic air separation unit consumes 0.357 kWh/kg power to produced LN2. (72) Therefore, 3.2 kW energy is required to ...Introduction · Numerical Methodology · Results and Discussion · Conclusions
[24]
Minimum work associated with separating nitrogen from air
Mar 1, 2024 · ... power range of 0.31–0.63 kWh/kg provided by Syakdani et al. ... This work itself helps to understand the power consumption levels of existing ...
[25]
https://www.industryresearch.biz/market-reports/industrial-nitrogen-market-109550
[26]
liquid nitrogen company list - Mordor Intelligence
Top 5 Liquid Nitrogen Companies · Air Liquide · Air Products and Chemicals, Inc. · Gulf Cryo · Linde plc · TAIYO NIPPON SANSO CORPORATION.
[27]
Industrial Pressure Swing Adsorption (PSA) Nitrogen Generation ...
Rating 4.8 (1,980) Oct 23, 2025 · Researchers are actively developing novel adsorbents with higher nitrogen adsorption capacities and faster kinetics, leading to reduced cycle ...
[28]
Cryocoolers - National Institute of Standards and Technology
The Stirling or Stirling-type pulse tube cryocoolers are most often used for such applications. Nitrogen or argon JT cryocoolers are used for the rapid cooldown ...
[29]
[PDF] SOLUTIONS FOR LIQUID NITROGEN PRE-COOLING IN HELIUM ...
Jul 26, 2000 · Pre-cooling of helium by means of liquid nitrogen is the oldest and one of the most common process features used in helium liquefiers and ...
[30]
Technology Profile: Production of Nitrogen from Air
Aug 1, 2021 · The process of recovering N 2 from air comprises three major sections: (1) purification; (2) refrigeration; and (3) rectification.
[31]
[PDF] i-- monitoring nitrogen purity n by gas chromatography - DTIC
Dec 12, 1985 · 2. Purity is the percent nitrogen and trace quantities of argon, neon and helium, Such inspections are deemed necessary to assure supplies and ...
[32]
Industrial Grade Nitrogen Classification & Purity Levels
Feb 13, 2025 · OFN gas is typically maintained at 99.998% nitrogen purity. This grade of nitrogen gas is useful in scientific research and calibration ...
[33]
https://www.rutherfordtitan.com/liquid-nitrogen-generators/liquid-nitrogen-price-usa/
[34]
Liquid Nitrogen Safety - Purdue Chemistry
Hand protection and goggles (not safety glasses) are to be worn when dispensing and handling liquid nitrogen. When handling large quantities, a full length ...
[35]
Fact Sheet: Intro to Cryogen Dewars | PennEHRS - UPenn EHRS
Jun 26, 2025 · This Fact Sheet provides an introduction to equipment used for storing, transporting, and delivering liquid cryogens and gases from liquid cryogens.
[36]
https://www.thomassci.com/laboratory-supplies/flasks/dewar-flasks
[37]
https://www.flinnsci.com/dewar-flask-small-1000-ml/ap1490/
[38]
https://www.tempshield.com/products/cryo-gloves
[39]
LN2 Phase Separators | From $67.97 | In Stock - CryoGear USA
LN2 Phase Separators are designed to minimize hazardous splashing and vaporization while transferring liquids into open containers from transfer hoses or ...
[40]
https://www.labrepco.com/product-category/cold-storage-products/ln2-cryogenic-storage/ln2-accessories/transfer-hoses-phase-separators-splitters/
[41]
Traceable® Thermometers for Liquid Nitrogen Monitoring
Traceable® and TraceableLIVE® Liquid Nitrogen Thermometers are perfect for monitoring sensitive biologicals, stem cells and other irreplaceable materials.
[42]
Dewar Operation - General Air
If you intend to use liquid product in your downstream application, the safety relief valve should be set at 22 psi, meaning the internal pressure of the tank ...
[43]
[PDF] LIQUID NITROGEN SAFETY GUIDELINES AND FAQS
Why Does a Tank Have Two Relief Valves? The tank supports two pressure settings (e.g., 22 psi and 230 psi). These are set during ordering and should not.
[44]
E1566 Standard Guide for Handling Hazardous Biological Materials ...
Jun 2, 2025 · 1.1 This guide covers recommended procedures for maintaining and handling hazardous biological materials at liquid nitrogen temperatures. 1.2 ...
[45]
Proper handling of Cryogenic Liquids - OARS
To protect against pressure build-up, use a pressure relief vessel or a venting lid. Liquid dewar flasks are non-pressurized, vacuum-jacketed vessels, somewhat ...
[46]
https://www.uvic.ca/ohse/_assets/docs/chemical-safety-folder/swp_ln2handling.pdf
[47]
[PDF] Liquid Nitrogen Safe Handling and Use - UVic
Feb 15, 2012 · Ensure liquid dewar flasks are non-pressurized, vacuum-jacketed vessels with loose fitting caps. • Liquid cylinders are pressurized containers ...
[48]
Chapter 29 – Safe Handling of Cryogenic Liquids
Jan 8, 2024 · In the case of liquid argon and liquid nitrogen, the nitrogen gas generated from malfunctioning equipment or spills will be cold and denser than ...Missing: interactions | Show results with:interactions
[49]
None
### Summary of Storage Practices for Liquid Nitrogen (AIGA 030/13)
[50]
[PDF] Cryogenic Standard Tanks LITS 2 - Linde
Boil-off rate. %/d LIN. 0.67. 0.58. 0.44 0.31 0.30 0.21 0.20. 0.19. 1 bar, 15°C A.T.. %/d LOX. 0.42. 0.37. 0.29 0.20 0.19 0.13 0.12 referred to total capacity.
[51]
22-0129 | PHMSA - Department of Transportation
Mar 21, 2023 · ... UN1977, Nitrogen, refrigerated liquid, 2.2” by highway transportation only. ... Specifications for UN portable tanks. U.S. DEPARTMENT OF ...
[52]
UN/NA 1977 - CAMEO Chemicals - NOAA
The ERG recommendations are developed for use during the initial phase of transportation incidents; they are not intended for spills at facilities. Material ...
[53]
Liquid Nitrogen Safety Requirements
### Liquid Nitrogen Safety Requirements Summary
[54]
[PDF] Commission Regulation (EU) 2020/878 - EUR-Lex - European Union
Jun 18, 2020 · Known and reasonably anticipated hazardous decomposition products produced as a result of use, storage, spill and heating shall be listed.
[55]
[PDF] Heat Transfer and Cooling Techniques at Low Temperature
In nitrogen, the heat flux is around 104 W·m–2 Ø10 mm tube for Ø10 mm and a mass flow rate of. 40 g·s1 for ΔT ≈ 2.5 K [25], whereas for helium the heat flux is ...
[56]
REBCO superconductors by pulsed laser deposition - PubMed Central
Remarkably, these materials exhibited critical temperatures exceeding 77 K—the boiling point of liquid nitrogen—rendering cryogenic cooling significantly more ...
[57]
[PDF] High Temperature Superconducting Magnets
(with liquid nitrogen). HTS magnets can operate with liquid nitrogen at ~77 K. • Liquid Nitrogen (LN2) is supplied in all quantities. • LN2 is ~100 times ...
[58]
[PDF] Benefit of Staged Cooling In Shrink Fitted Composite Cylinders
Mar 29, 2004 · This is followed by immersing the resulting trunnion-hub assembly into liquid nitrogen so that it can be then shrunk fit into the girder.
[59]
[PDF] cryogenic support thermal performance measurements
Thermal shrink fitting techniques are used to assemble the cryogenic support. The shrink fitted joint provides a tightly clamped connection between the ...
[60]
[PDF] Cryogenic Grinding
This cooling makes the materials brittle, allowing them to be easily shattered into fine powders without melting, smearing, or degradation.
[61]
A brief review on cryogenics in machining process
May 21, 2020 · The cryogenic-assisted machining process has proved to be successful in removing the heat and therefore accelerating the chip fragmentation ...
[62]
[PDF] Electronic Imaging in Astronomy - UCLA Infrared Lab
A typical mounting scheme for a CCD detector in a liquid-nitrogen cryostat. 221. 6.11. A cross-sectional view of a typical liquid-nitrogen (LN2) cryostat .
[63]
The Physics of Astronomical Infrared Detectors - NASA ADS
The development of infrared CCD's, however, has proceeded much more slowly ... Obviously, if cooling at liquid nitrogen or nitrogen temperatures is ...
[64]
[PDF] Design and Analysis of a Compact Dilution Refrigerator
Oct 24, 2017 · This paper proposes a compact dilution refrigerator insert to lower temperatures below 100 mK, aiming to replace a 1K cryostat insert. It is a ...
[65]
A numerical study on flow and heat transfer characteristics of the ...
Oct 28, 2025 · (2021) conducted experimental research on cryogenic cooling with liquid nitrogen, proposed the inverse global integration method, and found that ...
[66]
[PDF] A high efficiency and low vibration liquid nitrogen cooling system for ...
Oct 7, 2020 · The system uses liquid nitrogen phase change and natural convection to cool silicon crystals to sub-100K, providing over 80W cooling with low ...
[67]
Nitro Freezing: the future of desserts is here
Oct 2, 2024 · Flash or nitro freezing is one technique that has revolutionized dessert making. It involves freezing food using nitrogen and the results are truly remarkable.
[68]
Flash Frozen Dip & Dots Demo using Liquid Nitrogen - YouTube
Sep 11, 2013 · Chef Mike Brown demonstrates his Flash Frozen Dip and Dots recipe using liquid nitrogen. Mike is owner of Pig Ate My Pizza in the greater ...
[69]
Use of Liquid Nitrogen in Food Products: A Review - IADNS
May 20, 2025 · Liquid nitrogen (LN2) offers a promising alternative, reducing freezing time and preserving food structure and components. This review examines ...Introduction · Process Technology Involving... · Research Studies Concerning...
[70]
7 Common Molecular Gastronomy Techniques Explained
Using lab-like equipment such as liquid nitrogen and evaporators, this unique cooking style presents regular food in brand new ways that will blow your mind.
[71]
Liquid Nitrogen + Cream Charger: Advanced Techniques for ...
The instant freezing properties of liquid nitrogen rapidly fix the microstructure of ingredients, preventing ice crystal damage and creating smooth ice cream ...Missing: retention | Show results with:retention
[72]
Recent advances on applying for liquid nitrogen quick-freezing in ...
Aug 29, 2024 · Liquid nitrogen quick-freezing (LNF) provides a fast-freezing rate, minimal ice crystal formation, preservation of product texture and nutritional properties.
[73]
21 CFR 184.1540 -- Nitrogen. - eCFR
The affirmation of this ingredient as generally recognized as safe (GRAS) as a direct human food ingredient is based upon the following current good ...
[74]
[PDF] Liquid Nitrogen and Dry Ice in the Food Code - FDA
Oct 31, 2018 · The 2017 Food Code does not prohibit liquid nitrogen or dry ice, but they should not be added immediately before consumption and complete ...
[75]
Nitrogen Generators for Food Packaging | Common Questions to ...
Jan 13, 2020 · Consider if the generator produces food-grade nitrogen, meets FDA regulations, and meets EIGA containment specifications for food additive E941.
[76]
Homemade Caviar Pearls-Molecular Gastronomy, What??
1 hr 10 minFeb 27, 2022 · Liquid nitrogen is used in the preparation of those ice cream treats. ... liquid into chewy orbs resembling caviar. The tapioca pearls in ...
[77]
FROZEN: Cryogenic “Cooking” With Liquid Nitrogen - ChefSteps
Cryo poaching with liquid nitrogen is like deep frying, but using extreme cold instead of heat. A beignet batter is a foam. Put it into super-hot oil and the ...Missing: culinary | Show results with:culinary
[78]
Liquid Nitrogen Market Size & Trends Report, 2020-2025
The global liquid nitrogen market size was estimated at USD 15.33 billion in 2019 and is expected to expand at a compound annual growth rate (CAGR) of 5.6% ...Missing: 2020-2024 | Show results with:2020-2024
[79]
Vitrification versus slow freezing gives excellent survival, post ... - NIH
In the vitrification group versus slow freezing group, the survival rate (96.9% vs. 82.8%) and the post-warmed excellent morphology with all blastomeres intact ...
[80]
A comprehensive review and update on human fertility ...
Apr 18, 2023 · When it was evaluated both protocols using cryovials, sperm motility and DNA fragmentation levels were comparable (113). Recently, a study ...
[81]
Long-term Cryopreservation of Human and other Mammalian Cells at
May 29, 2018 · In this study, we investigated the effects of temperature during long-term storage (8 years at −80 °C and in liquid nitrogen phase) on the quality of various ...
[82]
Allogenic Lenticular Implantation for Correction of Refractive Error ...
... Corneal storage medium, Presbyopia, Hyperopia. Key ... 10 years [7–11]. When using cryopreservation, lenticules are generally stored in liquid nitrogen ...
[83]
Cryopreservation of Human Stem Cells for Clinical Application - NIH
This paper reviews the current state of cryopreservation as it pertains to stem cells and in particular the embryonic and iPS cell.
[84]
Cryotherapy for the skin: MedlinePlus Medical Encyclopedia
Jul 1, 2023 · Cryotherapy is done using a cotton swab that has been dipped into liquid nitrogen or a probe that has liquid nitrogen flowing through it.
[85]
Comparison of the Efficacy and Safety of Two Cryotherapy Protocols ...
Jul 13, 2020 · Cryotherapy is an effective and safe treatment for common viral warts of hands and feet. The impact of shorter intervals on cure rate was more significant.
[86]
High-resolution single-particle cryo-EM of samples vitrified in boiling ...
Samples for single-particle cryo-electron microscopy can be routinely vitrified using only liquid nitrogen at its boiling temperature, allowing sample ...
[87]
A General Method for Hyperquenching Protein Crystals - PMC - NIH
Protein crystals are typically cooled by inserting them into a cold nitrogen gas stream at T=100 K, by plunging into liquid nitrogen at Tb=77 K, or by plunging ...
[88]
AM23-ST-07-O: Standardization of Post-Thaw Viability Testing ...
Cryopreservation preserves hematopoietic progenitor cells (HPC) for future use, but the freezing and thawing processes can impact viability.
[89]
Practical Handbook of Cellular Therapy Cryopreservation - AABB
This handbook explains cryopreservation, including freezing cells, reading curves, handling abnormalities, and preventing cryoinjury, and covers product ...
[90]
Packaging, Inerting and Blanketing - Air Products
Nitrogen is an excellent inerting, blanketing and purging gas that can be used to protect valuable chemical products from harmful contaminants.
[91]
Drying, inerting, blanketing & purging - Linde Gas
Inert nitrogen gas effectively protects chemicals against oxygen and moisture, improving reaction safety and quality.
[92]
Most Common Uses of Nitrogen in Oil and Gas Industry | NiGen
May 28, 2019 · Nitrogen gas is incredibly useful in the upstream oil and gas industry for stimulating production in brownfields or reservoirs with low permeability.
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Edwards: How Cryogenics and High-Speed Vacuum Pumps Enable ...
Jul 16, 2024 · New etch process that operate at cryogenic or low-temperatures (near or below -100ºC) are making it possible to create very high aspect ratio ( ...
[94]
The key role of liquid nitrogen in semiconductor manufacturing
Aug 15, 2025 · Relevant studies show that after cooling with liquid nitrogen, the lattice damage during the ion implantation process is reduced by 40%, the ...
[95]
Cryopreservation of Semen in Domestic Animals - PubMed Central
Nov 24, 2022 · Cryopreservation is a way to preserve germplasm with applications in agriculture, biotechnology, and conservation of endangered animals.
[96]
Effect of Entomopathogenic Nematode Concentration on Survival ...
This is the first report of achieving 100% survival of an entomopathogenic nematode after preservation in liquid nitrogen. Maximum survival of H. bacteriophora ...Missing: agriculture | Show results with:agriculture
[97]
[PDF] Theatrical Fog, Smoke, and Haze Effects
Liquid nitrogen and argon can be used to create fog from water vapor in the air, or act as carriers mixed with other gas or chemical effects. These are also ...
[98]
High Duty Metal Additive Manufacturing Using Cryogenic Cooling ...
Oct 7, 2020 · A more efficient approach is the use of cryogenic cooling for either interpass cooling between deposits or in-situ cooling directly behind the torch for ...
[99]
Exploring the electrochemical and physical stability of lithium-ion ...
Jun 1, 2024 · The present study explores the effect of cryogenic freezing on the electrochemical and physical stability of Li-ion cells.
[100]
[PDF] Liquid nitrogen - Air Products
Latent Heat of Vaporization. 85.6 Btu/lb (199.1 kJ/kg). Expansion Ratio, Liquid to Gas, BP to 68°F (20°C). 1 to 694. Figure 1: Typical Dewar. Page 3. 3.
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https://www.latimes.com/business/story/2025-08-12/vernon-food-plant-to-plead-tktktk-after-nitrogen-leak-kills-two-workers
[102]
Liquid Nitrogen Can Cause Severe Burns - Poison Control
Mar 2, 2021 · Skin contact with LN can result in burns, blistering, and severe frostbite injury, which can occur within seconds of exposure. Skin damage from ...
[103]
Cryogenic Liquids - Princeton EHS
Liquid nitrogen will expand 696 times as it vaporizes. The expansion ratio of argon is 847:1, hydrogen is 851:1 and oxygen is 862:1.
[104]
[PDF] Hazards Associated with the Release of Liquid Nitrogen and Carbon ...
Frozen food production can be hazardous to workers. Although nitrogen and carbon dioxide can quickly freeze food products if released into the work area ...
[105]
Liquid Nitrogen Safety - Compressed Gas Association
These include extremely cold temperature, potential to create an oxygen-deficient atmosphere, and rapid conversion from a liquid to a gas.
[106]
First-Aid Procedures for Cryogenic-Induced Injuries | H2tools
Direct physical contact with liquid hydrogen, cold vapor, or cold equipment can cause serious tissue damage. Momentary contact with a small amount of the liquid ...
[107]
https://h2tools.org/bestpractices/dealing-with-incidents/first-aid-procedures-for-cryogenic-induced-injuries
[108]
None
Nothing is retrieved...<|separator|>
[109]
A chronology of human understanding of the nitrogen cycle - PMC
Nitrogen was officially discovered in 1772 by Scottish scientist Daniel Rutherford [6]. ... Between 1772 and 1780, Joseph Priestley isolated 10 different ...
[110]
The collaboration of Antoine and Marie-Anne Lavoisier and the first ...
Identification of the three respiratory gases. Lavoisier was the first person to clearly state the role of oxygen, carbon dioxide, and nitrogen in respiration.Missing: 1770s | Show results with:1770s
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Louis Paul Cailletet: The liquefaction of oxygen and the emergence ...
Oct 9, 2013 · Cailletet had claimed to have seen hydrogen mist in 1877, Raoul Pictet to have liquefied it in 1878 and Wróblewski to have done so in 1884 ...
[112]
Liquefaction of Oxygen | Nature
Cailletet's successful attempts to compress nitric oxide, N2O2, methyl hydride, CH4, and acetylene, C2H2, to the liquid form. The list of non-compressible gases ...
[113]
A tribute to Wróblewski and Olszewski - Europhysics News
More recently Zygmunt von. Wróblewski (1845-1888) and Karol Olszewski (1846-1915) acquired continental standing through their liquefaction achievements.
[114]
[PDF] Cryogenics - CERN Indico
1883 Karol Olszewski and Zygmunt Wróblewski liquefy air and its components. (77 K) – Cracow, Poland. 1895 Carl Linde starts LINDE AG.
[115]
[PDF] Louis Paul Cailletet-The liquefaction of the permanent gases
Liquefaction of oxygen represents a sensational scientific accomplishment that was achieved in 1877 almost simultaneously by Cai lletet and Raoul Pictet. ( 1846 ...
[116]
[PDF] 100 Years of Biochemistry at the University of Toronto 1908
Archibald Byron Macallum (1858-1934) F.R.S., F.R.S.C.. B.A. (1880) in Natural ... The nitrogen metabolism of B. granulobacter pectinovorum (degree not ...
[117]
In o r g an i c C h e mi s try. - RSC Publishing
Chlorine at -102" forms an orange-yellow liquid, in which yellow crystals separate; on lowering the temperature a few degrees, the whole liquid sodidifies to a ...
[118]
Carl von Linde and William Hampson – Cool inventions - Features
Sep 1, 2010 · Air separation – specifically, Hampson's liquid air machine – also paved the way for the discovery of several rare gases. Hampson delivered ...Missing: 1890s | Show results with:1890s
[119]
[PDF] Air separation plants - Linde
The internal compression (or liquid pumping) process allows for oxygen, nitrogen as well as argon to be compressed within the coldbox by means of liquid pumps, ...Missing: 2024 | Show results with:2024
[120]
4 - The Great Depression, the Second World War, and the industrial ...
In all, the East Asian country bought eight nitrogen plants from Linde over the course of this period, all destined for factories producing artificial ...
[121]
[PDF] Apollo Experience Report - The Cryogenic Storage System
The Apollo cryogenic storage system supplied fuel-cell reactants and oxygen for the crew for 14 days, using supercritical storage. It also provided oxygen for ...
[122]
The history of cryosurgery - PMC - NIH
Allington is generally thought to have been first to use liquid nitrogen, in 195017. He recognized that the properties of liquid nitrogen were very similar to ...
[123]
NEW, LOW-ENERGY PROCESSES FOR CRYOGENIC AIR ...
This paper presents several examples of new cryogenic processes for the separation of air which achieve significant improvements in energy efficiency.
[124]
Single photon emission up to liquid nitrogen temperature from ...
Jun 11, 2015 · By exploiting such material system, the SPS emission wavelength can be pushed towards the near-infrared spectral region, up to even 1.3–1.55 μm.
[125]
Air Liquide invests in the first world-scale oxygen production plant fit ...
Jul 23, 2020 · Air Liquide announces an investment of 125 million euros to build the first world-scale Air Separation Unit (ASU) for oxygen production with an energy storage ...Missing: green 2020s