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Spectral characteristics and laser performance of a bulk Tb3+-doped selenide glass were studied at room and liquid nitrogen temperatures. Under pumping with a pulsed 2.94 μm Er: YAG laser the output energy up to 36 mJ at 5.25 μm and wavelength tuning within 5.05–5.55 μm spectral range were demonstrated. [ABSTRACT FROM AUTHOR]

In this work, the tensile deformation mechanisms of the Fe55Co17.5Cr12.5Ni10Mo5−xCx-based medium-entropy alloy at room temperature (R.T.), 77 K, and 4.2 K are studied. The formation of micro-defects and martensitic transformation to delay the cryogenic fracture are observed. The results show that FeCoCrNiMo5−xCx-based alloys exhibit outstanding mechanical properties under cryogenic conditions. Under an R.T. condition, the primary contributing mechanism of strain hardening is twinning-induced plasticity (TWIP), whereas at 77 K and 4.2 K, the activation of martensitic transformation-induced plasticity (TRIP) becomes the main strengthening mechanism during cryogenic tensile deformation. Additionally, the carbide precipitation along with increased dislocation density can significantly improve yield and tensile strength. Furthermore, the marked reduction in stacking fault energy (SFE) at cryogenic temperatures can promote mechanisms such as twinning and martensitic transformations, which are pivotal for enhancing ductility under extreme conditions. The Mo4C1 alloy obtains the optimal strength–ductility combination at cryogenic-to-room temperatures. The tensile strength and elongation of the Mo4C1 alloy are 776 MPa and 50.5% at R.T., 1418 MPa and 71.2% in liquid nitrogen 77 K, 1670 MPa and 80.0% in liquid helium 4.2 K, respectively. [ABSTRACT FROM AUTHOR]

Pymetrozine is an insecticide that is widely used, causing severe environmental problems. This study determined the pymetrozine degradation by an enrichment culture of microorganisms from paddy soil. The results showed that the enrichment culture utilized 67.3 ± 10.1% of the pure substrate as the sole carbon and nitrogen source in liquid media after 36 h. However, the utilization rates of pymetrozine in herbicide were lower than those of the pure substrate. The maximum utilization rates of pure pymetrozine and pymetrozine in herbicide were 0.051 ± 0.006 and 0.039 ± 0.004 mmol/h, respectively. During the degradation, the metabolites 4-amino-6-methyl-4,5-dihydro-2H-[1,2,4]triazine-3-one and nicotinic acid were produced and then further degraded. In addition, the inoculation of a fungal strain, Phanerochaete sp. Th1, which degraded rice straw components, increased pymetrozine degradation in rice straw and soil. The study provides essential information on pymetrozine degradation in liquid media, rice straw during solid-state fermentation, and soil. [ABSTRACT FROM AUTHOR]

A recent trend is attracting consumers that take the form of smoky liquid nitrogen (LN2) food products. However, due to improper handling and a lack of knowledge of the potential health hazards, people are becoming prey to such repercussions as respiratory distress, skin necrosis and gastrointestinal injuries. We present here a case of a teenage boy with allergic rhinitis who was affected by the extreme cold generated during the consumption of "Nitrogen biscuit" who developed cough and exertional dyspnea, and who didn't respond to treatment in the local clinic and went on to suffer frequent bouts of illness. Upon presentation, his spirometry values were FEV1 65%, FVC 69% and FEV1/FVC 87.3 and a chest Xray revealed prominent bilateral broncho-vascular marking. The patient was given an inhaler containing corticosteroid and bronchodilator to relieve the bronchoconstriction, and follow-up spirometry after four months showed improvement. Awareness of risks associated with LN2-infused food at the point of sale is needed. [ABSTRACT FROM AUTHOR]

Simple Summary: Insects, because of their protein content and environmental advantages, have been considered a promising alternative to other traditional protein sources. The black soldier fly (BSFL) is one of the most studied insects given its use as an alternative feed for farmed animals (mammals, poultry, and fish). This study investigated the effect of the method of slaughter (freezing, blanching, Melacide® + freezing, and liquid nitrogen slaughter) and drying temperature (50, 70, and 90 °C) on the protein digestibility, proximal composition, and organic matter digestibility of BSFL meal. The results show that the best slaughter methods were slaughtering with liquid nitrogen and blanching, and 70 °C was the drying temperature that showed the best digestibility results while maintaining good hygienic–sanitary conditions. In recent years, the potential of insects as a sustainable protein alternative to feed the growing world population has been explored. Differences in the ways insects are processed can affect their proximate composition and digestibility. This work studied the effects of the combination of different types of slaughter methods and drying temperatures on the proximate composition, organic matter digestibility (OMd), hydrolysis degree (DH/NH2 and DH/100 g DM), total hydrolysis (TH), and hygienic and sanitary characteristics of BSFL (black soldier fly larvae) meal. Four types of slaughter methods were used including freezing (F), blanching + freezing (B), Melacide® + freezing (M), and liquid nitrogen slaughter (N). Each of these was used with three drying temperatures (50, 70, and 90 °C). A negative correlation between the acid detergent fiber (ADF) and protein digestibility parameters was obtained. The most suitable drying temperature was 70 °C, as it produced higher values of protein digestibility (DH and TH), resulting in hygienic and sanitary conditions suitable for food use. Slaughtering with liquid nitrogen and blanching was more conducive to achieving high protein digestibility results than traditional freezing or the use of Melacide®. [ABSTRACT FROM AUTHOR]

Osteosarcoma treatment with limb-sparing surgery using liquid nitrogen can be applied to canine patients experiencing diminished quality of life after leg amputation. In particular, forelimb amputation may affect gait more than hindlimb amputation. In this study, limb-sparing surgery using liquid nitrogen was applied to primary osteosarcomas arising in the proximal scapula of a Welsh Corgi, the proximal humerus of a Golden Retriever, and the distal radius of a Great Pyrenees, according to the protocol of Tsuchiya et al. In all cases, postoperative radiographic examination revealed bone union between the treated and matrix bones. All patients recovered their gait postoperatively. These results suggest that limb-sparing surgery using liquid nitrogentreated autologous bone is an effective option for patients with osteosarcoma. [ABSTRACT FROM AUTHOR]

• Improvement of surface integrity of AZ91 magnesium alloy using liquid nitrogen assisted milling and comparison with conventional dry milling. • Cryogenic milling minimized the machining temperature by about 29%, minimized the alloy surface roughness by about 28% and maximized the microhardness by about 23%. • Compressive residual stresses are generated in cryogenic milled surfaces. • No significant microstructural damages observed from both cryogenic and conventional milling operations. • The optimal process parameters for milling AZ91 alloy under both dry and cryogenic conditions have been identified. Use of magnesium is the need of the hour due to its low density as well as its high strength-to-weight and stiffness-to-weight ratio etc. This study focuses on the effectiveness of liquid nitrogen (LN 2) assisted cryogenic machining on the surface integrity (SI) characteristics of AZ91 magnesium alloy. Face milling using uncoated carbide inserts have been performed under liquid nitrogen (LN 2) assisted cryogenic condition and compared with conventional (dry) milling. Experiments are performed using machining parameters in terms of cutting speeds of 325, 475, 625 m/min, feed rates of 0.05, 0.1, 0.15 mm/teeth and depth of cuts of 0.5, 1, 1.5 mm respectively. Most significant surface integrity characteristics such as surface roughness, microhardness, microstructure, and residual stresses have been investigated. Behaviour of SI characteristics with respect to milling parameters have been identified using statistical technique such as ANOVA and signal-to-noise (S/N) ratio plots. Additionally, the multi criteria decision making (MCDM) techniques such as additive ratio assessment method (ARAS) and complex proportional assessment (COPRAS) have been utilized to identify the optimal conditions for milling AZ91 magnesium alloy under both dry and cryogenic conditions. Use of LN 2 during machining, resulted in reduction in machining temperature by upto 29% with a temperature drop from 251.2 °C under dry condition to 178.5 °C in cryogenic condition. Results showed the advantage of performing cryogenic milling in improving the surface integrity to a significant extent. Cryogenic machining considerably minimized the roughness by upto 28% and maximised the microhardness by upto 23%, when compared to dry machining. Cutting speed has caused significant impact on surface roughness (95.33% – dry, 92.92% – cryogenic) and surface microhardness (80.33% – dry, 82.15% – cryogenic). Due to the reduction in machining temperature, cryogenic condition resulted in compressive residual stresses (maximum σ ║ = -113 MPa) on the alloy surface. Results indicate no harm to alloy microstructure in both conditions, with no alterations to grain integrity and minimal reduction in the average grain sizes in the near machined area, when compared to before machined (base material) surface. The MCDM approach namely ARAS and COPRAS resulted in identical results, with the optimal condition being cutting speed of 625 m/min, a feed rate of 0.05 mm/teeth, and a depth of cut of 0.5 mm for both dry and cryogenic environments. [Display omitted] [ABSTRACT FROM AUTHOR]

Liquid nitrogen has shown excellent performances as a good fracturing medium in the extraction of unconventional natural gas, and its application in coalbed methane extraction is currently a research hotspot. This study focuses on the acoustic emission properties of coal specimens treated utilizing liquid nitrogen with varying initial temperatures in a three-point bending environment. Through examination of the load-displacement curves of the considered coal samples, their mechanical properties are also revealed for different initial temperatures and cycling frequencies. The findings demonstrate a gradual decline in the maximum load capacity of coal rock as the temperature rises. Similarly, when subjected to the same temperature, an escalation in the cycling frequency leads to a reduction in the peak load of coal rock. This suggests that both temperature and cycling frequency exert a notable impact on the fracturing efficacy of liquid nitrogen. Freeze-thaw cycling treatments and exposure to high-temperature conditions can activate preexisting damage in the coal rock, and, accordingly, influence its mechanical properties. In particular, throughout the progressive loading of coal rock samples, the failure mechanisms are predominantly characterized by the occurrence of tensile cracks, succeeded by the development, spread, and fracture of shear fissures. [ABSTRACT FROM AUTHOR]

Introduction and purpose. Preserving fertility is crucial for cancer patients, aligning with advancements in oncology. As survival rates improve, addressing treatment-related late effects gains importance. Many young patients, aware of therapy toxicity, consider future conception chances, impacting treatment decisions. With a trend toward delayed childbirth and a growing population facing unplanned family planning disruptions, the demand for fertility preservation is expected to rise. This paper provides a brief review of available methods for preserving fertility in cancer patients. State of knowledge. Freezing semen in liquid nitrogen vapor is a standard method for preserving reproductive potential in male cancer patients. Shielding during total-body radiation limits testicular volume reduction, indicating less damage to the germinal epithelium. Hormone suppression treatments are not protective in male cancer patients. Oocyte and embryo cryopreservation are considered secure methods before anticancer treatments, with oocyte cryopreservation being preferred for post-pubertal women. Ovarian tissue cryopreservation remains an alternative method without preliminary treatment, suitable when time is insufficient for ovarian stimulation. Ovarian transposition beyond the intended radiation area, performed laparoscopically, can retain ovarian function. GnRH agonist administration before and during chemotherapy aims to minimize the likelihood of premature ovarian insufficiency. Summary. Advancements in fertility preservation for cancer patients, ranging from traditional cryopreservation to innovative methods like ovarian tissue preservation, highlight a commitment to empowering individuals facing cancer diagnoses. Ongoing research expands possibilities, ensuring a diverse range of strategies that offer tangible and hopeful prospects at the intersection of cancer and reproductive health. [ABSTRACT FROM AUTHOR]

This study was conducted in two steps to evaluate the influence of freezing methods and natural extracts on cryopreserved ram sperm quality. Initially, the research compared the effects of two freezing methods: liquid nitrogen (LN2) versus −80 °C, on post-thawed ram semen on total and progressive motilities and velocity parameters. Experiment I revealed no significant differences (P > 0.05) between the LN2 and −80 °C freezing methods, indicating similar effects on the analyzed parameters. Experiment II aimed to examine the influence of Spirulina platensis (SP) and Salvia verbenaca (SV) extracts added to egg yolk extender on cryopreserved sperm quality, utilizing the −80 °C freezing method. Various concentrations (1.25, 3.75, 6.25 and 8.75 µg*mL−1) of acetone (Ac-SP and Ac-SV) and hexanoic (Hex-SP), as well as methanolic (MeOH-SV) extracts, were added into the extender. A thorough assessment of post-thawed sperm quality parameters, encompassing motility, velocity parameters, viability, membrane integrity, abnormality and lipid peroxidation was conducted. The outcomes demonstrated that 1.25 and 3.75 g*mL−1 of Ac-SP and Hex-SP and 1.25 µg*mL−1 of AC-SV and MeOH-SV increased the post-thawed ram sperm quality. In conclusion, this study emphasizes the antioxidant properties of SP and SV extracts, highlighting their potential to protect cryopreserved sperm cells from oxidative stress at −80 °C. [ABSTRACT FROM AUTHOR]

The application of liquid nitrogen is being considered nowadays because it is clean and environmentally friendly and improves product quality. The cryogenic cooling can also be useful in hard machining process where workpiece is exposed to high thermo-mechanical loads. Thermal loads are one of the factors affecting residual stresses and microstructural changes in a material. There is no study in literature to evaluate the effect of cryogenic cooling for evaluation of thermo-mechanical loads during the machining of the hardened AISI H13 steel. Therefore, in the present study, to control and investigate the thermal loads, microhardness, white layer thickness, and surface quality in hard machining of AISI H13 steel, the cryogenic cooling system was employed during the process. Results indicated that depth of cut was the most influential item on temperature enhancement of cutting zone, while high feed rates were responsible for enhancement of microhardness surface roughness. Intense and rapid cooling using the liquid nitrogen spraying was found effective strategy to reduce white layer thickness and improve surface quality at the machined surface. [ABSTRACT FROM AUTHOR]

The development of ultrafine particles provided a new way to solve problems in the fields of energy, environment, and medicine, and had become one of the most promising technologies. Therefore, the application of ultrafine particles required the development of cleaner, greener, and more efficient preparation methods. The new freeze-dissolving technology has been applied in manufacturing of KHCO3 ultrafine particles, with an aqueous solution of 0.02–0.1 g KHCO3/g water. Frozen ice particles were formed after dripping the solution into liquid nitrogen. The antisolvent ethanol was used to dissolve the ice spherical template at a temperature below 273.15 K, and the pre-formed KHCO3 ultrafine particles inside the ice template remained in the ethanol aqueous solution. The ice particles were put into the freeze dryer to isolate the ultrafine KHCO3 particles. Compared with the particles produced with traditional freeze-drying technology, the ultrafine powder/particles produced by the freeze-dissolving technology were smaller with narrower size distribution. The freeze-dissolving technology has demonstrated a much more sustainable and efficient manufacturing process than the traditional freeze-drying process. In addition, the influence of the concentrations of KHCO3 and the sizes of ice particles were investigated with the discussions of mechanisms. [ABSTRACT FROM AUTHOR]

Ultralow-temperature fluids (such as liquid nitrogen, liquid CO2) are novel waterless fracturing technologies designed for dry, water-sensitive reservoirs. Due to their ultralow temperatures, high compression ratios, strong frost heaving forces, and low viscosities, they offer a solution for enhancing the fracturing and permeability of low-permeability reservoirs. In this study, we focus on the combined effects of high-pressure fluid rock breaking, low-temperature freeze-thaw fracturing, and liquid-gas phase transformation expansion on coal-rock in low-permeability reservoirs during liquid nitrogen fracturing (LNF). We systematically analyze the factors that limit the LNF effectiveness, and we discuss the pore fracture process induced by low-temperature fracturing in coal-rock and its impact on the permeability. Based on this analysis, we propose a model and flow for fracturing low-permeability reservoirs with low-temperature fluids. The analysis suggests that the Leidenfrost effect and phase change after ultralow-temperature fluids enter the coal support the theoretical feasibility of high-pressure fluid rock breaking. The thermal impact and temperature exchange rate between the fluid and coal determine the temperature difference gradient, which directly affects the mismatch deformation and fracture development scale of different coal-rock structures. The low-temperature phase change coupling fracturing of ultralow-temperature fluids is the key to the formation of reservoir fracture networks. The coal-rock components, natural fissures, temperature difference gradients, and number of cycles are the key factors in low-temperature fracturing. In contrast to those in conventional hydraulic fracturing, the propagation and interaction of fractures under low-temperature conditions involve multifield coupling and synergistic temperature, fluid flow, fracture development, and stress distribution processes. The key factors determining the feasibility of the large-scale application of ultralow-temperature fluid fracturing in the future are the reconstruction of fracture networks and the enhancement of the permeability response in low-permeability reservoirs. Based on these considerations, we propose a model and process for LNF in low-permeability reservoirs. The research findings presented herein provide theoretical insights and practical guidance for understanding waterless fracturing mechanisms in deep reservoirs. [ABSTRACT FROM AUTHOR]

This study evaluated two distinct cryo-fracturing techniques using liquid nitrogen (LN2). The evaluation included tests for peak compression strength, acoustic emission, and energy absorption. The experiments compared single-exposure freezing time (FT) and multiple-exposure freezing–thawing cycle (FTC) processes on dried specimens. The outcomes indicated that FTC experiments demonstrated lower uniaxial compression stress (UCS) values compared to FT experiments because, during the thawing phase, the ice inside the pores reverts to liquid as the temperature rises. The difference between average baseline experiments versus FT180 and FTC6 indicated a reduction in stress of 14.5% and 38.5%, respectively. The standard error of our experiments ranged from 0.58% for FT60 to 5.35% for FTC6. The damage factor follows a downward trend in both FT and FTC experiments as the time of LN2 treatment augments. The amount of energy that can be absorbed in elastic or plastic deformation before failure is less for FTC specimens with the same total LN2 exposure time. Samples undergoing the freezing time process demonstrate a greater and denser quantity of acoustic emissions in comparison to freezing–thawing cycle processes, suggesting a positive correlation with uniaxial compressive strength outcomes. The large network of fractures formed by the FTC and PFTC techniques indicated that they have the greatest potential as stimulation approaches. The engineering results were improved by adding the geological context, which is essential to apply these findings to coals that have comparable origins. [ABSTRACT FROM AUTHOR]

DNA analysis plays a crucial role in forensic investigations, helping in criminal cases, missing persons inquiries, and archaeological research. This study focuses on the DNA concentration in different skeletal elements to improve human identification efforts. Ten cases of unidentified skeletal remains brought to the Institute of Forensic Medicine in Timisoara, Romania, underwent DNA analysis between 2019 and 2023. The results showed that teeth are the best source for DNA extraction as they contain the highest concentration of genetic material, at 3.68 ng/µL, compared to the petrous temporal bone (0.936 ng/µL) and femur bone (0.633 ng/µL). These findings highlight the significance of teeth in forensic contexts due to their abundant genetic material. Combining anthropological examination with DNA analysis enhances the understanding and precision of identifying human skeletal remains, thus advancing forensic science. Selecting specific skeletal elements, such as the cochlea or teeth, emerges as crucial for reliable genetic analyses, emphasizing the importance of careful consideration in forensic identification procedures. Our study concludes that automated DNA extraction protocols without liquid nitrogen represent a significant advancement in DNA extraction technology, providing a faster, more efficient, and less labor-intensive method for extracting high-quality DNA from damaged bone and tooth samples. [ABSTRACT FROM AUTHOR]

The impact of cryogenic pretreatments on drying performance was studied in blueberries, seabuckthorn fruits and green grapes. The fruits were immersed in liquid nitrogen in 2 min freezing/thawing cycles (one to five). Untreated samples were used as the control. Drying experiments were carried out on treated and non-treated berries at 50 °C and 1 m/s (hot-air-drying), 50 °C and 25″ Hg vacuum (vacuum-drying), 30 mTorr total pressure and 25 °C shelf temperature (freeze-drying). The weight loss evolution of the foodstuffs was measured as a function of time. Microscopic (SEM and optical) determinations of the epicarp were performed. A visual inspection was performed and color changes and volume reductions were assessed before and after dehydration. The thickness of the berries' epicarp decreased between 20 and 50% (depending on the fruit) after 3–5 immersions in liquid N2. The drying kinetics was accelerated significantly for the three tested drying processes (i.e., drying time decreased from 48 to 16 h for blueberry freeze-drying). The best quality of dried berries was observed for pretreated blueberries after freeze-drying, keeping their volume, shape and color after the process. This work shows that "tailor-made" dried berry products with desired properties can be achieved and drying performance can be improved by the application of ultra-low temperature pretreatments. [ABSTRACT FROM AUTHOR]

Tracer injection has long been recognized as a valuable tool for delineating tree hydraulics and assessing water transport pathways. Recently, isotope tracers have emerged as innovative instruments for investigating tree hydraulics, providing new insights into tree water dynamics. Nevertheless, there is a critical need for further research to comprehensively grasp water movement and distribution within trees. A previously introduced technique for analyzing the isotopic ratio of water in wet tissues, offering millimeter‐scale resolution for visualizing tracer movement, faces challenges due to its underdeveloped sample preparation techniques. In this study, we introduced an H218O tracer into S. gracilistyla samples, exclusively comprising indeterminate roots, stems, and leaves, cultivated through hydroponics and grown within the current year. Our objective was to assess the axial distribution of the tracer in the xylem. Additionally, we devised a novel method for preparing frozen wet tissue samples, enhancing the repeatability and success rate of experiments. The results demonstrated that all frozen wet tissue samples exhibited an average water loss rate of less than 0.6%. Isotopic analysis of these samples unveiled a consistent decline in tracer concentration with increasing height in all Salix specimens, with three out of five samples revealing a significant isotope gradient. Our findings affirm the efficacy and practicality of combining isotopic labeling with freezing, stabilization, and preparation techniques. Looking ahead, our isotopic labeling and analysis methods are poised to transcend woody plants, finding extensive applications in plant physiology and ecohydrology. [ABSTRACT FROM AUTHOR]

Adipose tissue in the human body occurs in various forms with different functions. It is an energy store, a complex endocrine organ, and a source of cells used in medicine. Many molecular analyses require the isolation of nucleic acids, which can cause some difficulties connected with the large amount of lipids in adipocytes. Ribonucleic acid isolation is particularly challenging due to its low stability and easy degradation by ribonucleases. The study aimed to compare and evaluate five RNA and DNA isolation methods from adipose tissue. The tested material was subcutaneous porcine adipose tissue subjected to different homogenization methods and RNA or DNA purification. A mortar and liquid nitrogen or ceramic beads were used for homogenization. The organic extraction (TriPure Reagent), spin columns with silica-membrane (RNeasy Mini Kit or High Pure PCR Template Preparation Kit), and the automatic MagNA Pure system were used for the purification. Five combinations were compared for RNA and DNA isolation. Obtained samples were evaluated for quantity and quality. The methods were compared in terms of yield (according to tissue mass), purity (A260/280 and A260/230), and nucleic acid degradation (RNA Integrity Number, RIN; DNA Integrity Number, DIN). The results were analyzed statistically. The average RNA yield was highest in method I, which used homogenization with ceramic beads and organic extraction. Low RNA concentration didn't allow us to measure degradation for all samples in method III (homogenization with ceramic beads and spin-column purification). The highest RNA quality was achieved with method IV using homogenization in liquid nitrogen and spin column purification, which makes it the most effective for RNA isolation from adipose tissue. Required values of DNA yield, purity, and integrity were achieved only with spin column-based methods (III and IV). The most effective method for DNA isolation from adipose tissue is method III, using spin-columns without additional homogenization. [ABSTRACT FROM AUTHOR]

The structure and properties of materials are determined by a diverse range of chemical bond formation and breaking mechanisms, which greatly motivates the development of selectively controlling the chemical bonds in order to achieve materials with specific characteristics. Here, an orientational intervening bond‐breaking strategy is demonstrated for synthesizing ultrathin metal–organic framework (MOF) nanosheets through balancing the process of thermal decomposition and liquid nitrogen exfoliation. In such approach, proper thermal treatment can weaken the interlayer bond while maintaining the stability of the intralayer bond in the layered MOFs. And the following liquid nitrogen treatment results in significant deformation and stress in the layered MOFs' structure due to the instant temperature drop and drastic expansion of liquid N2, leading to the curling, detachment, and separation of the MOF layers. The produced MOF nanosheets with five cycles of treatment are primarily composed of nanosheets that are less than 10 nm in thickness. The MOF nanosheets exhibit enhanced catalytic performance in oxygen evolution reactions owing to the ultrathin thickness without capping agents which provide improved charge transfer efficiency and dense exposed active sites. This strategy underscores the significance of orientational intervention in chemical bonds to engineer innovative materials. [ABSTRACT FROM AUTHOR]

Background Quercus: seeds that are recalcitrant to desiccation and freezing temperatures cannot be stored in gene banks under conventional conditions. However, the germplasm of some recalcitrant seeded species can be stored in liquid nitrogen (–196 °C). Unfortunately, for many species, among them for almost the whole genus Quercus, an effective cryostorage method is still unknown. In this study, we propose a successful cryostorage protocol for Quercus petraea (Matt.) Liebl. germplasm using plumules (a shoot apical meristem of an embryo) frozen on aluminium cryo-plates. Results: The plumules isolated from the acorns of ten provenances were prestored in 0.5 M sucrose solution (for 18 h). To form alginate beads (one plumule per bead), the plumules were placed in the wells of a cryo-plate and embedded in calcium alginate gel. For cryoprotection, the encapsulated plumules were immersed in cryoprotectant solution containing 2.0 M glycerol and different concentrations of sucrose (0.8–1.2 M) for 40 min at 25 °C and desiccated under a laminar flow cabinet for 1.0–4.0 h. Cryo-plates with plumules were directly immersed in liquid nitrogen and then cryostored for 30 min. For rewarming, cryo-plates with plumules were immersed in 1.0 M sucrose solution and rehydrated for 15 min at 25 °C. Survival rates varied from 25.8 to 83.4 were achieved after cryoprotection in 1.0 M sucrose solution and the drying of plumules for 2 h. The in vitro regrowth rate of cryopreserved plumules varied among provenances and was 26–77%. Conclusions: This study presents, for the first time, a successful, simple and effective protocol for the cryopreservation of Q. petraea germplasm that could be used in gene banks. The experiment was successfully repeated on seeds from various provenances, each yielding similar, good results. However, seed quality and storage time after harvesting are important factors in plumule regrowth after cryopreservation. [ABSTRACT FROM AUTHOR]

In this work, a successful cryopreservation method of date palm tissue cultures by vitrification was established. Callus and somatic embryos of three date palm cultivars were exposed to dimethylsulfoxide (DMSO) and Plant Vitrification Solution 2 (PVS2) for different durations before plunging into liquid nitrogen for cryoprotection. After freezing phase, the cryopreserved cultures were thawed and cultured on recovery media. Among different times of exposure to DMSO (10%), 60 min gave best results of survival and regrowth of the date palm tissue cultures. Regarding recovery, 'Zaghlool' cultivar gave the highest values of callus fresh mass (0.5 g) and growth value (1.00). Also, the highest differentiation percentages (75%) and number of proliferated shootlets (8.50) were recorded with 'Zaghlool' cultivar. Concerning PVS2, survival and regrowth gradually increased as exposure time increasing till 30 min and then decreased. Unlike of callus cultures, the survival and regrowth rates of somatic embryos were relatively higher at all PVS2 exposure time. With regard to recovery, the genotype effect took same trend in cryopreservation of callus cultures, since 'Zaghlool' was superior in growth parameters in comparison to the other two cultivars. On the other hand, genetic stability of the cryopreserved date palm tissue cultures was assessed using ISSR markers. Among four screened primers, three gave monomorphic bands; all of these banding profiles were similar to those of noncryopreserved cultures. Generally, the results of ISSR showed high genetic similarity suggesting that cryopreservation using vitrification does not affect genetic stability of date palm tissue cultures. The results of this study demonstrated PVS2 was more effective in cryoprotection of date palm tissue cultures compared with DMSO and cryopreservation by vitrification is a suitable tool for conservation of genetic stable date palm germplasm. [ABSTRACT FROM AUTHOR]

The paper presents the beginning of the research on the characteristics of albino beech in the Central Serbia region. The studied beech is perennial, of sprout origin, fruitful, and most likely parasitic on the parent tree, considering that its lack of chlorophyll renders it unable to feed and grow on its own. By measuring the physical characteristics of common and albino beeches that share the same root system, and by comparing the length and width of their leaves, the obtained results show that the leaves of albino beech are noticeably smaller. The average length of leaves of common beech is 7.19 cm, while the average length of leaves of albino beech is 6.08 cm. The average width of leaves of common beech is 3.83 cm, whereas the average width of leaves of albino beech is 3.35 cm. To achieve transpiration as a basic physiological function of any tree form, albinism causes significant weakening of the maximum strength and sap during water transport. Additionally, since the leaf is deprived of any of the essential pigments - chlorophyll (a, b, c, d), anthocyanin, carotene - this results in dwarf growth or the formation of bush-like forms of trees. For genome sequencing, it is planned to take samples of leaves with and without pigment and preserve them in liquid nitrogen at a temperature of -195℃ in special canister freezers with liquid nitrogen. The view on the phenomenon and the potentially still unrecognized mechanisms of functioning of the plant itself, as well as the plants around it, fungi associated with its root system, or even the discovery of a completely new network or system of connections, remains to be uncovered. What enables the nutrition and influx of basic sugars into this plant may be revealed through the sequencing of its entire genome, which is a basic, logical, and one of the first steps to be taken. The exact location of the plant is kept confidential at this time. [ABSTRACT FROM AUTHOR]

Liquid nitrogen freeze–thaw (LNFT) cycles can realize the high-volume fracturing of coalbed methane (CBM) reservoirs, because they can effectively improve the distribution of pores and cracks inside coal. To quantitatively evaluate the mechanical behaviors and permeability evolution law of coal with LNFT cycles, the mechanical and permeability tests of the coal subjected to LNFT cycles under different geological conditions are performed. The structural damage of the coal under different LNFT cycles is analyzed from both macro- and micro-perspectives. The results indicate that under a low confining pressure, the LNFT cycle treatment can significantly aggravate the deterioration of mechanical properties of coal; whereas this deterioration effect will be weakened to some extent under a high confining pressure. The coal treated with LNFT cycles tends to shear failure under no confining pressure. However, under confining pressure, the coal treated with LNFT cycles is more prone to tensile failure, especially under relatively high confining pressure. The permeability of the coal presents a natural logarithm increase with LNFT cycles. The changes in the coal permeability are controlled by the internal structure of coal and the gas rarefaction effect. With the increase of LNFT cycles, the coal permeability change becomes more sensitive to confining pressure and gas pressure due to the gas rarefaction effect. During the LNFT of the coal, the temperature gradient mainly produces macro-main cracks, while the anisotropy of the thermal expansion coefficient of mineral grains, water–ice phase transition, and liquid nitrogen vaporization mainly induce internal micro-cracks including intergranular cracks and intragranular cracks inside the coal. The ideal number of LNFT cycles for CBM reservoirs is closely related to the geological condition including in situ stress and pore pressure. Highlights: The mechanical parameters and failure behavior of coal treated with liquid nitrogen freeze–thaw cycles have an obvious confining pressure effect. The gas rarefaction effect inside coal is significantly affected by liquid nitrogen freeze–thaw cycles and confining pressure. The ideal number of liquid nitrogen freeze–thaw cycles for CBM reservoirs is closely related to in-situ stress and pore pressure. The structural damage of coal under different liquid nitrogen freeze–thaw cycles is analyzed from both macro and micro scales. [ABSTRACT FROM AUTHOR]

The cryogenic cycling freeze–thaw technique demonstrates significant applicability in extracting coalbed methane (CBM) from low-permeability saturated coal seams. However, due to the inability to effectively predict the degree of structural damage to coal-rock at different times and impact radii in practical engineering, it severely affects the efficient extraction of CBM. Therefore, by conducting stepwise low-temperature single-cycle freeze–thaw tests on water-saturated coal-rock specimens at − 196 ℃ (the low temperature of liquid nitrogen), − 45 ℃, − 30 ℃, and − 15 ℃, the damage characteristics of the coal-rock specimens after freeze–thaw are determined and analyzed. Additionally, a physical model is established to calculate the damage range of liquid nitrogen freeze–thaw in coal-rock. Finally, through comparison with existing research results and numerical simulation of liquid nitrogen low-temperature freezing heat transfer, the accuracy of the experiments and physical models is ensured. The research results indicate that with the increase in stepwise low temperatures, the temperature stress caused by temperature changes gradually decreases, leading to a gradual reduction in the freeze–thaw damage to the coal-rock specimen structure. It is calculated that under the − 15 ℃ low-temperature environment, the temperature stress is only 0.72 MPa, which represents the effective temperature for enhancing transparency in freeze–thaw damage to coal-rock structures within a single cycle. Based on the established physical model and combined with experimental results, it is possible to rapidly and accurately predict the degree of damage to coal-rock at different locations, the impact range of liquid nitrogen injection wells, and the time required for heat transfer. This aids researchers in scientifically locating liquid nitrogen injection wells and CBM extraction wells, thereby enhancing work efficiency, reducing costs, and promoting efficient, green CBM extraction. [ABSTRACT FROM AUTHOR]

In this paper, the cavitation and flow characteristics of the unsteady liquid nitrogen (LN2) cavitating flow in a submersible pump are investigated through both experimental and numerical approaches. The performance curve of the LN2 submersible pump is obtained via experimental measurement. Numerical simulations are performed using a modified shear stress transport k–ω turbulence model, incorporating corrections for rotation and thermal effects as per the Schnerr–Sauer cavitation model. The numerical framework is verified by comparing the cavitation morphology features with previously reported visual data of the LN2 inducer and aligning pump performance data with those obtained from experimental tests of the LN2 submersible pump. The results indicate that cavitation at the designed flow rate predominantly manifests as tip clearance vortex cavitation in the inducer. Increased flow rates exacerbate cavitation, potentially obstructing the flow passage of the impeller. The vortex identification method and the vorticity transport equation are employed to identify the vortex structures and analyze the interaction between cavitation and vortices in the unsteady LN2 cavitating flow. The vortex structures primarily concentrate at the outlet of the impeller flow passage, largely attributed to the vortex dilation term and baroclinic torque. The influence of thermal effects on the cavitation flow of submersible pumps is analyzed. An entropy production analysis model, comprehensively involving various contributing factors, is proposed and utilized to accurately predict the entropy production rate within the pump. This study not only offers an effective numerical approach but also provides valuable insight into the cavitation flow characteristics of the LN2 submersible pump. [ABSTRACT FROM AUTHOR]

For X-ray applications, microcalorimeters are increasingly dependent on the superconducting transition-edge sensor (TES) technology. We are developing TES devices based on Mo–Cu bilayer films for the proposed Hot Universe Baryon Surveyor (HUBS) satellite mission. To investigate the possible impact of a space radiation environment on the stability of the bilayer films, we conducted an irradiation experiment on Mo–Cu bilayer samples with 1 MeV protons at room temperatures and liquid nitrogen temperatures. With data recorded in real time, we noticed that the changes in the electrical resistance of the film samples were not apparent during irradiation at room temperatures, before and after irradiation, but were evident at liquid nitrogen temperatures. Furthermore, following the irradiation runs, we warmed up the irradiated film samples and placed them in a refrigerator to measure their superconducting transition temperatures ( T c ) and residual resistivity ( ρ 3 K ). We found no systematic change in T c and ρ 3 K . We discuss the results in terms of the vacancies and interstitials in the test samples that are produced by irradiation, as well as the effects of heating caused by irradiation. [ABSTRACT FROM AUTHOR]

With the decarbonization and electrification of modern railway transportation, the demand for both the high-capacity electrical energy and hydrogen fuel energy is increasingly high. A novel scheme was proposed from liquid hydrogen production by surplus wind and solar energy, to liquid hydrogen-electricity hybrid energy transmission for railway transportation. The 100 MW hybrid energy transmission pipeline was designed with the 10 kA/1.5 kV superconducting DC cable for electricity and cryogenic layers for liquid hydrogen and liquid nitrogen, showing strong capability in transmitting "electricity + cold energy + chemical energy" simultaneously. Economic evaluation was performed with respect to the energy, equipment capacity, and costs, with sensitivity and profitability analysis. With the discount rate 8%, the dynamic payback period of the hybrid energy pipeline was 7.1 years. Results indicated that the shortest dynamic payback period of the hybrid energy pipeline was 4.8 years, with the maximum transmission distance 93 km. Overall, this article shows the novel concept and design of liquid hydrogen-electricity hybrid energy pipelines, and proves the technical and economic feasibilities for future bulk hybrid energy transmission for railway transportation. • A novel scheme of hydrogen-electricity hybrid energy transmission for railway transportation. • A MW-class superconducting hybrid energy pipeline for electricity + cold energy + chemical energy. • Economic evaluation for energy, equipment capacity, and cost. • Technical and economic feasibilities for future bulk hybrid energy transmission. [ABSTRACT FROM AUTHOR]

Linum usitatissimum commonly known as flax fibers, emerges as a promising reinforcement phase for artificial polymer resins, boasting ecological benefits, low density, and easy accessibility. However, the mechanical behavior of such composites hinges crucially on factors such as fiber mat thickness, nanoTiO2 filler content, and the application of cryogenic treatment. Addressing this complex interplay, this study employs a hand lay-up technique for composite construction, subjecting nanocomposite plates to the challenging liquid nitrogen conditions at 77 K post-manufacture. Recognizing the need for an optimized approach, Response Surface Methodology (RSM) based on Box-Benhken designs is employed to enhance the mixing features of linum usitatissimum polymer composites. The study calculates anticipated mechanical strength values through rigorous ANOVA inferential analysis, uncovering the pivotal roles played by fiber mat thickness, nanofiller content, and cryogenic treatment in the two feature interactions (2FI) model components. The methodology proves robust with high R2 values (0.9670 for tensile, 0.9845 for flexural, and 0.9670 for interlaminar shear strength) consistently aligning with experimental findings. The study culminates in identifying optimized parameters for maximal mechanical properties--300 gsm flax fiber thickness, 5 wt.% nano TiO2 concentration, and a 15-min cryogenic treatment--a result that advances our understanding of fundamental factors influencing composite performance and provides practical guidelines for applications in fields requiring superior mechanical strength in challenging environments. [ABSTRACT FROM AUTHOR]

A liquid nitrogen cooling circulating unit is a necessary condition for the stable operation of a cryogenic oscillator, which can provide a stable working environment for the oscillator. In this paper, according to the user's functional requirements and performance parameters, a closed cooling system with supercooled liquid nitrogen as the medium was designed using SOLIDWORKS 2021 software, which can provide a suitable working environment for the cryogenic oscillator. Combined with the system heat load analysis, theoretical calculation for and the design of the coil heat exchanger, one of the core pieces of equipment of the unit, were carried out. The performance of the designed nitrogen exhaust heater was studied using FLUENT 2021 software, and the velocity field and temperature field of the nitrogen exhaust heater were analyzed. The results show that the outlet temperature of the nitrogen exhaust heating device can reach up to 310 K, and the outlet flow rate of the heating device is 0.01528 kg/s. The experiments on the liquid nitrogen circulating unit using the simulated load equipment show that the refrigeration power of the unit can reach a design index of 600 W, and the temperature of the liquid nitrogen at the liquid outlet of the unit can reach 77.8 K. The experiments also show that the unit meets the design requirements. [ABSTRACT FROM AUTHOR]

Recent research has mostly focused on replacing traditional lubricants with nanoparticle-based fluids to increase machining performance. The current work compares three distinct environmental conditions in turning of A286 alloy: oil machining (OM), nano Low Quantity Lubrication (nLQL), and LN2 (liquid nitrogen). Cutting speed (Vs), environment, and feed rate (f) were used as control parameters, with responses assessed in terms of flank wear (Vb), crater wear, surface roughness (Ra), machining temperature (Mt), and chip morphology. The L27 array was chosen for the testing runs. The experimental findings demonstrated that LN2 cooling significantly lowered Ra by 54% and 24%, Vb by 62% and 53%, and Mt by 45% and 73% when compared to the OM and nLQL settings. Under cryogenic circumstances, surface integrity was also enhanced. COPRAS, a multi-response optimization approach, was used to determine the best trials for picking the best outcomes. [ABSTRACT FROM AUTHOR]

To investigate the mechanism of flow-induced vibrations in the cooling system of a double crystal monochromator (DCM), this paper utilizes a multi-physics numerical simulation approach, employing ANSYS and FLUENT platforms to simulate the flow state of liquid nitrogen in the cooling system and explore the amplitude response of the DCM. Initially, simulations were conducted to examine the flow state of liquid nitrogen with varying frequency and amplitude pulsations. Subsequently, modal analysis was employed to investigate the amplitude response of the DCM in the pitch direction vibrations under pulsating excitation. Finally, this research investigated the influence of high heat load-induced liquid nitrogen boiling on a DCM. The results indicate that pipe resistance is the fundamental cause of vibration induced by pulsating excitation. Low-frequency excitation enhances the amplification factor of DCM vibration. In contrast, due to the rapid conversion of fluid kinetic energy to pressure potential energy, high-frequency excitation increases the pulsation amplitude in the pipe. Additionally, there is a linear relationship between the amplitude of liquid nitrogen velocity fluctuations and the response amplitude of a DCM. The slug flow formed after liquid nitrogen boiling generates low-frequency pulse signals, and intermittent fluid impacts cause significant vibrations in the DCM. These research findings provide a reference for the analysis and design of ultra-high-stability DCM cooling systems. [ABSTRACT FROM AUTHOR]

This research has dealt with the simulation of liquid nitrogen cavitation inside a convergent nozzle. This is important in cryogenic industrial applications. So in this study, computational fluid dynamics methods have been used for simulating the cavitation phenomenon. The Two-phase model in this research has been a hybrid/mixed model. Also, k- ε turbulence model has been employed in realizable state. For meshing the nozzle geometry, Gambit software has been used, while for numerical simulation, Ansys Fluent software has been employed. For simulation of cavitation, Schnerr and Sauer cavitation model has been utilized. This research has also examined the effect of changing the nozzle outlet diameter and the impact of changing the pressure difference in the inlet and outlet of the nozzle on the cavitation. As a novelty and unlike what would have been expected based on the Bernoulli effect, the results obtained from the simulation showed that the increase/decrease in the nozzle's outlet diameter resulted in an enhanced/diminished extent of cavitation in the nozzle's outlet region. Also, the increase/decrease of the pressure difference in the input and output of the nozzle would lead to a higher/lower extent of cavitation. This research also found that the effect of altering the nozzle's outlet diameter on the extent of cavitation has been far higher than the effect of changing pressure difference in its inlet and outlet. The results also indicated that upon reduction of the nozzle's outlet diameter from the base state (1.02 mm) by 10, 20, 30, 40, and 50 %, the volume fraction of the vapor diminished by 22.23, 43.029, 60.66, 74.73, and 87.16 % respectively. Finally, with the increase in the nozzle's outlet diameter from the base state (1.02 mm) by 10, 20, 30, 40, and 50 %, the volume fraction of the vapor increased by 26.83, 55.27, 84.47, 117.12, and 149.31 % respectively.

The publications in the field of cryogenic-technologies’ applications in the processes of the thermal and deformation treatments of metals are reviewed. The most effective fields of the applications of cryogenic liquids and gases for the heat treatment of working tools and metals (titanium, aluminium, and copper alloys) are in the rolling production and heavy engineering in order to improve the product quality, equipment and tool durability, to reduce the impact on the environment and operating personnel. The effects of cryogenic treatment and cooling on the tool life, wear, cutting temperature, surface roughness, dimensional accuracy, and cutting force are considered. As a result, the use of cryogenic processing and cryogenic cooling in machining processes increases the tool life and improves surface roughness as well as reduces the temperature of the machined surface, energy consumption during operation, and, thus, reduces tool wear that contributes to an increase in productivity. The possibility of obtaining and changing the nanostructure of a metal through the cryogenic cooling is also considered. The topic may be of interest for researchers and scientists in the field of metallurgy, materials science, and nanotechnologies.

Due to its boiling point of −196 °C, liquid nitrogen is a cryogenic substance which is commonly used in many industries for its cooling properties. However, this extreme cooling capability means that it also has the potential to inflict severe full-thickness burns. Despite its widespread use in the workplace, very little has been described in the literature regarding complex reconstruction of liquid nitrogen burns. We present a case that is unique, not only in its unusual mechanism of injury but also in that it is the first described case of free tissue reconstruction of cryogenic burns. [ABSTRACT FROM AUTHOR]

Cobalt-based superalloys are widely used in hot-end components of gas turbines due to their excellent elevated temperature mechanical properties. At present, cobalt-based superalloys are usually machined under cutting fluid, which will seriously pollute the environment and harm human health. Cryogenic cutting technology uses liquid nitrogen, supercritical carbon dioxide, etc. as the cooling medium, which has the advantages of environmental protection and energy conservation. In this paper, the cryogenic mechanical properties of cobalt-based superalloy GH605 were investigated, and then the cutting experiments were conducted under three different cooling and lubrication methods (flood condition, cryogenic minimum quantity lubrication, and liquid nitrogen) to investigate the cryogenic machinability and machining sustainability of GH605. The results show that cryogenic temperature can reduce the plasticity of GH605 but has little effect on the compressive yield strength and compressive strength. Compared with the cutting fluid, the cutting force of liquid nitrogen is reduced by up to 72.2%, the cutting-specific energy is reduced by about 83.9%, and the concentration of particulate matter such as PM2.5 generated during the processing can be decreased by more than 60%. The surface finish and consistency of cryogenic minimum quantity lubrication are better; the surface roughness is reduced by 0.4 ~ 20.4% at different cutting speeds. When the feed speed is greater than 0.10 mm/r, the work hardening degree decreases by 0.8 ~ 19.7%. Under the two cooling strategies, the chip surface is smooth and flat, chip breaking property is improved, but the machining noise is more than 100 dB. [ABSTRACT FROM AUTHOR]

Simple Summary: It remains unclear whether the prolonged preservation of cells, such as sperm, in liquid nitrogen (LN2) leads to their deterioration over time. In this study, we investigated whether the conservation of Iberian pig semen for ten years results in a decline in quality and whether the evaporation of LN2 from the tanks between refills could be a contributing factor. Furthermore, the only way to improve already-frozen samples is to implement specific thawing protocols. Thus, our findings suggest that only samples consistently submerged in LN2 benefit the most from the application of thawing protocols, such as rapid thawing at 70 °C for 8 s. While partial conservation in LN2 and LN2 vapors does not result in a loss of quality over time, it does cause damage that thawing protocols cannot mitigate. This finding suggests that, independently of the lack of the effect of the level of storage in the tank, careful handling and optimization of thawing protocols are essential for the quality preservation of the cryopreserved sperm samples. The conservation of genetic resources in pig breeds, notably the Iberian pig, is crucial for genetic improvement and sustainable production. Prolonged storage in liquid nitrogen (LN2) is recognized for preserving genetic diversity, but potential adverse effects on seminal quality remain debated. This study aims to assess the impact of ten years of storage at different LN2 levels and to optimize thawing protocols for Iberian pig sperm. Sperm samples from 53 boars were cryopreserved and stored at varying LN2 levels and, a decade later, the samples were thawed at 37 °C for 20 s or at 70 °C for 8 s. Sperm motility, membrane integrity, acrosome status, and DNA fragmentation were evaluated in year 0 and year 10. Overall, no significant differences were observed in post-thaw sperm quality between storage levels in year 0 or year 10. But thawing at 70 °C 8 s showed significant improvements, particularly in samples that were always stored in LN2, in all analyzed parameters except fragmentation, which was not affected by cryostorage. This study suggests that the long-term preservation of Iberian pig sperm does not affect quality over time, regardless of whether the samples were fully submerged in LN2. Furthermore, it is determined that thawing at 70 °C for 8 s maximizes post-thaw sperm quality, especially in those samples stored constantly submerged in LN2. [ABSTRACT FROM AUTHOR]

Quasi‐solid thermogalvanic hydrogels hold great promise in harvesting low‐grade thermal energy, yet, they are still far from practical application owing to relatively low power output. Herein, through liquid nitrogen quenching‐induced structure engineering, a high‐performance stretchable thermogalvanic hydrogel thread with a high specific output power density of 2227.5 µW m−2 K−2 and a large thermopower of 4.5 mV K−1 is designed. After liquid nitrogen quenching, both the thermopower and electrical conductivity have been greatly improved compared to natural cooling. The excellent properties are attributed to liquid nitrogen quenching‐induced grain refinement and precipitation inhibition. It is a novel and general preparation method for high‐performance and homogeneous thermogalvanic hydrogels. Finally, a thermogalvanic hydrogel array is demonstrated to be capable of driving a low‐power motor and charging a mobile phone by low‐grade thermal energy harvesting, indicating a great potential for practical applications in human daily life. [ABSTRACT FROM AUTHOR]

Background: The frozen inactivation of autologous tumor bones using liquid nitrogen is an important surgical method for limb salvage in patients with sarcoma. At present, there are few research reports related to frozen inactivated autograft replantation. Methods: In this study, we retrospectively collected the clinical data of patients with bone and soft tissue sarcoma treated with liquid nitrogen-frozen inactivated tumor bone replantation, and analyzed the safety and efficacy of this surgical method. The healing status of the frozen inactivated autografts was evaluated using the International Society of Limb Salvage (ISOLS) scoring system. Functional status of patients was assessed using the Musculoskeletal Tumor Society (MSTS) scale. Results: This study included 43 patients. The average length of the bone defect after tumor resection is 16.9 cm (range 6.3--35.3 cm). Patients with autograft not including the knee joint surface had significantly better healing outcomes (ISOLS scores) (80.6% ± 15% vs 28.2% ± 4.9%, P<0.001) and limb function (MSTS score) (87% ± 11.6% vs 27.2% ± 4.4%, P<0.001) than patients with autografts including the knee joint surface. The healing time of the end of inactivated autografts near the metaphyseal was significantly shorter than that of the end far away from the metaphyseal (9.8 ± 6.3 months vs 14.9 ± 6.3 months, P=0.0149). One patient had local recurrence, one had an autograft infection, five (all of whom had an autograft including the knee joint surface) had joint deformities, and seven had bone non-union. Conclusion: Frozen inactivated autologous tumor bone replantation is safe and results in good bone healing. But this method is not suitable for patients with autograft involving the knee joint surface. [ABSTRACT FROM AUTHOR]

The use of liquid nitrogen fracturing can effectively improve the permeability of unconventional natural gas reservoirs. In order to explore the impact of liquid nitrogen cooling on the tensile failure behavior of coal and sandstone, a series of physical and Brazilian splitting tests were conducted on coal and sandstone. Compared with the control group, the velocity, tensile strength, and splitting modulus reduction of coal were 24.7%, 19.7%, and 52.4%, respectively, and the corresponding reductions for sandstone were 5.5%, 14.7%, and 15.4%. Energy analysis and failure characteristics demonstrated that liquid nitrogen cooling promoted widespread distribution of internal damage in coal and sandstone, and the degree of internal structure damage determined the complexity of the failure mode. The greater the internal damage, the more branch cracks occurred during failure, and the greater the path tortuosity and degree of fragmentation. [ABSTRACT FROM AUTHOR]

Microwave and liquid nitrogen have shown great potential applications in the mining, geological, petroleum, and particularly metal mining fields. In order to further promote their application in rock tunneling engineering, this paper conducted a series of I-model fracture tests on hard rock (granite) to explore the impact of liquid nitrogen, microwave, and liquid nitrogen and microwave pretreatment on the fracture characteristics of hard rock. The results showed that compared with the control group, all pretreatment groups had varying degrees of reduction in wave speed and fracture toughness, especially the microwave and liquid nitrogen group. [ABSTRACT FROM AUTHOR]

In this research work, we have synthesized non-crystalline Se85Te3Bi12 chalcogenide glasses by conventional melt quenching technique. The differential scanning calorimetry measurement of the synthesized specimen was done to confirm the glassy as well as non-crystalline nature of the bulk Se85Te3Bi12 alloy. The nano-thin films of thickness 30 nm of the synthesized sample at two different ambient argon pressures (1 Torr and 3 Torr) were made using the physical vapor condensation technique at a constant substrate temperature of 77 K using liquid nitrogen. The non-appearance of prominent peaks in the high-resolution x-ray diffractometer profile confirmed the non-crystalline nature of synthesized nano-thin films. The morphological analysis of the prepared nano-thin films using Field emission scanning electron microscopy confirmed the nanochalcogenide having particle size ranges from 30–90 nm. The Fourier transform infrared (FTIR) spectroscopy suggests the presence of moisture and carbon impurities in the prepared nano-thin films. The broad optical transmission shadow observed in the FTIR results is an essential requirement for new-generation IR systems. Based on UV-visible spectroscopy, optical parameters such as optical absorption coefficients, Urbach energy, optical band gaps, Tauc's parameter and extinction coefficients were measured for synthesized Se85Te3Bi12 nano-thin films. The value of absorption coefficients, Tauc's parameters, optical band gap and extinction coefficients increases with the increase of ambient argon pressure. The outcome of these studies recommends that these materials can be a preeminent candidate for photovoltaic applications. Photoluminescence spectroscopy results are accredited to the accumulation of non-crystalline nanochalcogenide particles on the substrates. DC conductivity measurements further confirm the semiconducting nature of the nanochalcogenide Se85Te3Bi12 thin films. [ABSTRACT FROM AUTHOR]

BOG re-liquefaction process is a necessary part for the safety of LNG cargo ships, and it is also the most common way to deal with evaporated gas (BOG) in LNG ships. Therefore, how to optimize the re-liquefaction process and save energy consumption is a problem that cannot be ignored in BOG re-liquefaction system. In this paper, based on the traditional BOG re-liquefaction process, a liquid nitrogen precooling circulation system is added and linked with the nitrogen purging system. Aspen HYSYS software was used to simulate and analyze the exergy efficiency, specific power consumption, exergy efficiency in the proposed liquefaction process. In addition, we introduced a bacterial foraging algorithm to optimize the process parameters. According to the operation results, the optimized process has a specific power consumption of 1.028 kWh/kg LNG , which is 21.53 % lower than that of the original NH 3 and CO 2 precooling system. Changing the traditional precooling system to liquid nitrogen tank reduces the complexity of the liquefaction system and improves the reliability of the system. Because liquid nitrogen has excellent cryogenic energy, small size, cheap price, safety in the actual use process and the linkage with the purge device on board, it shows excellent performance in the process of BOG pre-cooling liquefaction. [ABSTRACT FROM AUTHOR]

The susceptibility of LIBs to fire and explosion under extreme conditions has become a significant challenge for large-scale application of lithium-ion batteries (LIBs). However, the suppression effect of fire-extinguishing agent on LIBs fire is still far from being satisfactory attributed to special combustion characteristics of LIBs fire. This manuscript provides a comprehensive review on the origin and behavior of LIBs fire, and the selection of the typical fire-extinguishing agents for LIBs. Novel fire suppression strategies are also discussed. Several agents such as liquid nitrogen, dodecafluoro-2-methylpentan-3-one (C6F12O) and water-based fire-extinguishing agents possess better fire-extinguishing and cooling capabilities. Unfortunately, there are some shortcomings that restrict their application. The ideal fire-extinguishing agents for LIBs should be both highly thermally conductive, highly electrically insulating, highly efficient in extinguishing LIBs fire, cheap, non-toxic, residue-free and toxic gases-absorbing. Some perspectives and outlooks are given that the combination of ideal fire-extinguishing agent and novel fire-extinguishing strategy can insure a high level of safety for present and future LIB-based technologies. [ABSTRACT FROM AUTHOR]

Coalbed methane (CBM) is an important unconventional fuel source, and its efficient extraction is of great significance in reducing greenhouse gas emissions, energy requirements, and coal mine safety. Liquid nitrogen (LN2) fracturing is a popular super-cryogenic waterless fracturing method used for enhancing CBM recovery processes. Understanding the behavior of coal fractures under LN2 cyclic fracturing is crucial for revealing the fracture mechanism. In this study, we applied micro-computed tomography (μCT) and the deep learning method to quantify the evolution of volume size, spatial distribution, connectivity, and thickness of 3D fractures in coal under LN2 cyclic fracturing. In addition, the spatial topological and geometric distribution of 3D fractures were further characterized by the pore network model (PNM). A coal microfracture segmentation method from a 2D U-Net model to a 3D U-Net model was proposed to segment fractures automatically and accurately with an average Dice coefficient of 0.942. The results show that LN2 treatment can effectively damage the coal sample and promote the expansion and formation of fractures. The porosity, fracture connectivity, and thickness increase with the number of LN2 cycles, and the increase in the first cycle is significantly higher than in the subsequent cycles. The PNM analysis indicates that the number and equivalent diameter of pores and throats, as well as the coordination numbers, increase with the cycles while the average throat length decreases. Furthermore, the increase in the size of fractures and the formation of large fractures would greatly reduce the P-wave velocity and weaken the uniaxial compressive strength, which decreases by 26.5% and 73.5% after four LN2 fracturing cycles, respectively. Finally, the mechanism of LN2 cyclic fracturing is discussed based on experimental results. The findings of this study provide a deeper understanding of the application of LN2 cyclic fracturing in CBM reservoir recovery. Highlights: The coal microstructure is precisely extracted using a combination method of μCT scanning and 3D U-Net. The evolution of coal 3D microstructure under LN2 cyclic fracturing is visualized and quantitatively analyzed. LN2 cyclic fracturing has a higher efficiency on CT slices with small initial porosity. The effect of fracture size on coal P-wave and mechanical properties was revealed. [ABSTRACT FROM AUTHOR]

Objective: This study evaluated the effects of temperature and storage time on the quality and DNA integrity of freeze-dried sperm from individuals with normozoospermia. Methods: Normal sperm samples from 15 men aged 24 to 40 years were studied. Each sample was divided into six groups: fresh, freezing (frozen in liquid nitrogen), freeze-dried then preserved at room temperature for 1 month (FD-1m-RT), freeze-dried then preserved at room temperature for 2 months (FD-2m-RT), freeze-dried then preserved at 4 °C for 1 month (FD-1m-4 °C), and freeze-dried then preserved at 4 °C for 2 months (FD-2m-4 °C). The morphology, progressive motility, vitality, and DNA integrity of the sperm were evaluated in all groups. Results: In all freeze-dried groups, sperm cells were immotile after rehydration. The freeze-dried groups also showed significantly less sperm vitality than the fresh and frozen groups. Significantly more morphological sperm abnormalities were found in the freeze-dried groups, but freeze-drying did not lead to a significantly higher DNA fragmentation index (DFI). The DFI was significantly higher in the FD-2m-RT group than in the other freeze-dried groups. Conclusion: The freeze-drying method preserved the integrity of sperm DNA. The temperature and duration of storage were also identified as factors that influenced the DFI. Accordingly, more research is needed on ways to improve sperm quality in the freeze-drying process. [ABSTRACT FROM AUTHOR]

The current work presents a 3D numerical investigation of heat transfer characteristics of twin heaters exposed to cooling. The liquid nitrogen is considered as the fluid medium for heat rejection. Six distinct heater configurations are taken into account and the impact of heater configuration on flow and heat transfer pattern is demonstrated. The heaters provide heat at a steady rate (W/m3). The velocity and temperature contours, average Nusselt number ( Nu Avg ) , the maximum vertical velocity of fluid flow, and average velocity of fluid flow is plotted for all the six heater configurations for the comparative study. Moreover, another parametric study has been done to find the optimum spacing between two heaters for the best heat transfer rate. The reliance on average Nusselt number, average fluid flow velocity, entropy generation as a function of heat generation rate for various heater configurations are outlined graphically. The after-effects of this study show that heater configurations can impressively influence the heat transfer rate, fluid flow characteristics, and entropy generation under the same heat generation rate in the heater. The most noteworthy Nu Avg on the heater surface is acquired when heater configuration is circular. In each one of the heater configurations, the value of Bejan number is under 0.5. Henceforth, it may be expressed that irreversibility because of fluid friction prevails over irreversibility because of heat transfer. [ABSTRACT FROM AUTHOR]