Liquid Nitrogen Research Articles

Bundle effect on a helical coil in liquid nitrogen with pool boiling for liquid oxygen densification

The need to densify oxidizers using cryogenic fluids is increasing to enhance the performance of launch vehicles. One of the most practical methods for oxidizer densification is heat exchange cooling between liquid oxygen and liquid nitrogen, typically using a tube bundle heat exchanger. Due to the multiple tubes in the bundle, a bundle effect arises, which enhances convective heat transfer by inducing liquid agitation from bubble generation and rising. This paper presents experimental results and prediction models that account for bubble behavior in a tube bundle. The experiment is conducted with saturated liquid nitrogen in a pool at atmospheric pressure and helical coil-type heat exchangers instead of a traditional tube bundle stack heat exchanger. Liquid oxygen densification is achieved by varying mass flow rates and inlet temperatures. Single-passage helical coils made of copper are used to minimize uncertainty from maldistribution flow and reduce thermal resistance compared to convective heat transfer coefficients in the inner and outer tubes. The coils, with an outer diameter of 12.7 mm, were tested in both vertical and horizontal directions and with various coil pitches. The bundle effect was clearly observed under helical coil conditions, and the experiment confirmed that the convective heat transfer coefficient increased with increasing heat flux and bubble generation rate. The prediction models considering bubble behavior—rising and generation rate—were validated by comparison with experimental results. The forced convective Nusselt number, experimentally measured to range from 23 to 361 through its correlation with the Boiling Reynolds number, closely followed the predicted correlation curve of the bubble generation model. It demonstrated a mean absolute error of 83.3, a standard deviation of 65.6, and an average relative error of 64.8 %. These values show improved accuracy compared to the relative errors of two predicted curves in the bubble rising model: 216 % for the single circular tube correlation and 381 % for tube bank correlations. This improvement suggests that the increased bubble generation rate with heat flux is better reflected for liquid oxygen densification with a helical coil submerged in large-scale static pool condition.

Taxifolin: A flavonoid in the freezing medium augments post-thaw semen quality and in vivo fertility potential of buffalo bull spermatozoa

This comprehensive study was carried out to investigate the effects of taxifolin in the freezing medium on post-thaw semen quality, and fertility potential of buffalo bull spermatozoa. Taxifolin was also evaluated for radical scavenging activity through DPPH (2, 2-diphenyl-1-picrylhydrazyl), and Nitric oxide (NO) inhibition (%) during in vitro conditions. Collected semen samples from four buffalo bulls were initially evaluated (consistency, volume, motility, and concentrations); the accepted samples were pooled, and diluted in extenders containing different doses of taxifolin (0 μM [control], 2 μM, 5 μM, 10 μM, and 20 μM). Diluted semen was gradually cooled (2 h, 4 °C), equilibrated (4 h, 4 °C), and then frozen in liquid nitrogen (−196 °C). Data analysis revealed that taxifolin supplementation (10 μM) displayed the highest DPPH-scavenging ability, and NO inhibition compared to the control (% DPPH, 67.31 vs. 13.50; and % NO, 78.25 vs. 21.25) respectively. Moreover, taxifolin supplementation (10 μM) significantly (P < 0.05) improved progressive motility (%), average path velocity (μm/sec), straight-line velocity (μm/sec), and seminal plasma glutathione peroxidase (μM), and superoxide dismutase (U/mL) of buffalo bull spermatozoa than control. Sperm plasma membrane integrity, mitochondrial transmembrane potential, acrosome integrity (%) and seminal plasma adenosine triphosphate (nmol/million), and total antioxidant capacity (μM/L) were enhanced significantly with taxifolin (10 and 20 μM) supplementing group. Lastly, taxifolin supplementation significantly improved the fertility rate (%, 69.09 vs. 40.38) compared to the control. Further studies to assess mechanisms by which taxifolin improves semen quality and fertility of buffalo spermatozoa are warranted.

The Behaviour of carbon quantum dots and cryogenic cooling in turning of super duplex F 53 steel

The objective of this research is to examine how various cooling and lubrication techniques affect the machinability of Duplex F53 steel when turning it, with particular attention to residual stress, surface roughness, chip morphology, tool wear, machining temperature, and crystallographic structures. According to the microstructure analysis, the presence of additional austenite grains at high temperatures during dry machining results in an increase in hardness. On the other hand, cooling techniques including liquid nitrogen (LN2), carbon Quantum dots with SQL (CD), and oil with small quantity lubrication (OSQL) produce larger ferrite grains, which lower hardness. According to residual stress analysis, the high temperatures during dry cutting result in increased strains, which are successfully mitigated by lubrication. The two-phase microstructure has a crucial influence in mechanical characteristics, as demonstrated by X-ray diffraction (XRD) studies, wherein finer grains improve surface polish but demand more energy. Measuring surface roughness (Ra) reveals that adhesion wears during dry machining raises Ra, while OSQL and LN2 cooling lower Ra and improve surface quality. Tool performance is negatively impacted by high machining temperatures. Cutting temperatures and friction are greatly reduced by LN2 cooling. Dry machining increases tool wear because of the high temperatures and absence of lubrication; OSQL and CD lower wear rates, while LN2 offers the best protection for tools. Thinner, better-separated chips are produced by effective lubrication in OSQL and LN2, while thicker, more deformed chips are produced by dry machining, according to chip morphology and thickness analyses. The study leads to the conclusion that super duplex steel's surface quality, tool life, and machinability can all be significantly enhanced by carbon quantum dots and cryogenic cooling.

Practical magneto-optical imaging of the current density of coated conductors within liquid nitrogen

Magneto-optical imaging (MOI) is widely used for magnetic studies of superconducting materials due to its advantages of full-field, real-time operation and high resolution. However, a traditional MOI system requires vacuum pumping, thermal shielding, and cooling by thermal conducting, thereby making the system very complex and expensive and increasing the time required to complete a set of experiments. In this study, a novel (to our knowledge) and practical approach for MOI within liquid nitrogen (LN) is proposed in which thermal conducting, thermal shielding, and vacuum pumping are no longer necessary. The key technique is realized through a semi-immersed polymethyl methacrylate (PMMA) bar in LN, and its size is optimized to ensure a stable temperature difference and polarized optical visualization within LN. With the improvised method, a defect in a superconducting layer of length approximately 250 µm in the coated conductor (CC) sample was detected. Additionally, the current density reduced by approximately 50% in magnitude compared to its neighbor region, thus demonstrating the effectiveness of the new approach. It is expected that this technique can further enhance the application of MOI as an efficient tool for industrial inspection of superconducting CCs.

Physiological and Molecular Responses of Red Amaranth (Amaranthus cruentus L.) and Green Amaranth (Amaranthus hypochondriacus L.) to Salt Stress

AbstractSalinization, as a serious climate change phenomenon, continues to cause critical issues for soils and crops. Abundance of genetic diversity of plants could contribute in solving the impacts of salinity. However, the relations between physiological and molecular traits of plant species need deep investigation and interpretation. Pot experiments were conducted in the greenhouse to investigate the difference in behavior between two amaranth species when they were beforehand subjected to salinity-stress conditions, specifically on some specific physiological and molecular characteristics. After 45 days from transplanting, salt stress was induced using a 150 mM sodium chloride solution. Treatments were arranged in randomized complete block design using three replications. After 0, 2, 6, 10, and 24 h, samples were collected to evaluate physiological data as well as diversity of gene expression. The samples were immediately frozen in liquid nitrogen and stored in -80⁰ C ultralow temperature refrigerators. Findings revealed that the red amaranth species (Amaranthus cruentus) was more tolerant to saline stress than the green amaranth species (Amaranthus hypochondriacus). Result data revealed that malondialdehyde (MDA) content in the red amaranth increased after 2 h then decreased (after 6 and 10 h) before rising again after 24 h. In the green amaranth, MDA content initially decreased after 2 h before increasing and later decreasing in a zigzag pattern ending in an increase after 24 h. There was an initial steep rise in proline content of green amaranth after 2 h which continued to still rise moderately till 24 h. In the red amaranth the initial rise in proline continued after 2, 6 and 10 h before it stopped. Results also showed that red amaranth gave higher value of superoxide dismutase (SOD) activity as compared with green amaranth in all tested salinity exposure times. The investigation on the expression of four genes assessed through quantitative PCR indicated the efficiency of red amaranth in increasing the expression of SOS1, HKT1, NHX1, and DGR2 genes, which encode adaptation-related proteins under salinity stress. In summary, the current work demonstrated that red amaranth could be an efficient genetic resource in improving salt-tolerant genotypes belonging to Amaranthus genus.

Percutaneous cryoablation in soft tissue tumor management: an educational review

Abstract Background Percutaneous cryoablation (PCA), having shown effectiveness in treating liver, lung, prostate, breast, and kidney tumors, is now gaining attention for the treatment of soft tissue tumors. PCA functions by freezing tissue, which induces ice crystal formation and cell death without damaging collagen structures. Technical considerations include the selection and handling of cryoprobes and cryogenic agents, procedural duration, and choice of image guidance for precision. This review aims to synthesize the mechanisms, applications, and technical aspects of PCA in the treatment of soft tissue tumors. Methods Adhering to PRISMA 2020 guidelines, a review was conducted of studies published prior to March 2024 that investigated PCA of soft tissue tumors. The review focused on technical and procedural aspects of cryoablation, cryobiological principles, cellular and tissue responses to extreme cold, intra- and post-procedure physiological mechanisms during and post-procedure, and main clinical applications. Results PCA is efficient in treating soft tissue tumors, including desmoid tumors, vascular malformations, and abdominal wall endometriosis. Several cryobiological mechanisms are involved, notably ice crystal formation, cellular dehydration, osmotic effects, and the inflammatory response, all of which contribute to its efficacy. Key technical aspects include the choice of cryoprobes, cryogenic agents (argon gas or liquid nitrogen), and the duration and control of freezing/thawing cycles. PCA also frequently outperformed traditional treatments like surgery and radiotherapy in terms of pain reduction, tumor size reduction, and patient outcomes. Moreover, its nerve sideration properties make it effective under local anesthesia. Conclusion Demonstrating substantial pain reduction, tumor size decrease, and high technical success rates, PCA offers a promising and minimally invasive alternative for soft tissue tumor treatment. Critical relevance statement Percutaneous cryoablation provides a minimally invasive, precise alternative for soft tissue tumor management, advancing clinical radiology by offering effective treatment with reduced patient risk and enhanced outcomes through image-guided procedures. Key Points Percutaneous cryoablation (PCA) offers a promising, minimally invasive alternative for managing soft tissue tumors. PCA employs image-guided techniques to accurately target and treat tumors, ensuring high precision and control. PCA preserves structures like collagen, reduces pain, decreases tumor size, and generally enhances patient outcomes. Graphical Abstract

Optoelectronic performance prediction of HgCdTe homojunction photodetector in long wave infrared spectral region using traditional simulations and machine learning models.

This research explores the design of an infrared (IR) photodetector using mercury cadmium telluride (Hg1-xCdxTe). It proposes two- and three-dimensional homojunction models based on p+-Hg0.7783Cd0.2217Te/n--Hg0.7783Cd0.2217Te, focusing on applications in the long-wavelength infrared range. The photodetector's performance is analyzed using Silvaco ATLAS TCAD software and compared with analytical calculations based on drift-diffusion, tunneling, and Chu's approximation techniques. Optimized for operation at 10.6μm wavelength under liquid nitrogen temperature, the proposed photodetector demonstrates promising optoelectronic characteristics including the dark current density of 0.20mA/cm2, photocurrent density of 4.98A/cm2, and photocurrent density-to-dark current density ratio of 2.46 × 104, a 3-dB cut-off frequency of 104GHz, a rise time of 0.8 ps, quantum efficiency of 58.30%, peak photocurrent responsivity of 4.98A/W, specific detectivity of 3.96 × 1011cmHz1/2/W, and noise equivalent power of 2.52 × 10-16W/Hz1/2 indicating its potential for low-noise, high-frequency and fast-switching applications. The study also incorporates machine learning regression models to validate simulation results and provide a predictive framework for performance optimization, evaluating these models using various statistical metrics. This comprehensive approach demonstrates the synergy between advanced materials science and computational techniques in developing next-generation optoelectronic devices. By combining theoretical modeling, simulation, and machine learning, the research highlights the potential to accelerate progress in IR detection technology and enhance device performance and efficiency. This multidisciplinary methodology could serve as a model for future studies in optoelectronics, illustrating how advanced materials and computational methods can be utilized to enhance device capabilities.

Effects of oxidative stress on the changes of viability of Paeonia lactiflora seeds with different water content before and after cryopreservation.

Cryopreservation in liquid nitrogen (LN) is an efficient long - term seed preservation strategy and water content is one of the main factors affecting seed viability after cryopreservation. In this study, Paeonia lactiflora seeds with varying water content were used as materials to determine changes in the antioxidant system before and after cryopreservation. When the water content of P. lactiflora seeds was 15.96% - 10.12%, the viability of P. lactiflora seeds decreased significantly compared with that of the seeds without cryopreservation, but at the water content of 8.14% - 7.56% there were no significant differences. However, when the water content of P. lactiflora seeds decreased to 6.01% - 5.19% the viability was slightly increased compared to the seeds without cryopreservation. The content of superoxide anion (O2-), hydroxyl radical (·OH), hydrogen peroxide (H2O2), malondialdehyde (MDA) and protein carbonyl group (PCO) of seeds with high water content (15.96% - 10.12%) were significantly increased after cryopreservation. However, superoxide anion (O2-), hydroxyl radical (·OH) and hydrogen peroxide (H2O2) did not change significantly in seeds with low water content (6.01% - 5.19%) after cryopreservation, while oxidative stress indexes MDA and PCO decreased. These three substances were significantly negatively correlated with seed viability. In terms of antioxidant substances, the contents of catalase (CAT), ascorbic acid (AsA) and glutathione (GSH) decreased and the activities of glutathione reductase (GR) and dehydroascorbate reductase (DHAR) increased during the cryopreserved process of seeds with varying water content. These changes were significantly correlated with ROS content and the changes of MDA and PCO, among which AsA content, GSH content and CAT activity were positively correlated with seed viability. The changes of GR and DHAR activity were negatively correlated with seed viability. In summary, when the water content of the seeds ranged from 8.14% - 5.19%, ROS content did not increase significantly after cryopreservation compared with that of before preservation. The changes of MDA and PCO contents before and after cryopreservation, it was inferred that no obvious oxidative damage occurred in seeds, so the viability of seeds did not decrease compared with that of before cryopreservation. Therefore, the optimum water content of P. lactiflora seeds for cryopreservation is 8.14% - 5.19%.

Simulations of Cryogenic Line Chilldown with Advanced Subgrid Wall Boiling Models

A mesoscale model for boiling processes in water was adapted for cryogens and demonstrated for chilldown of propellant transfer lines in both liquid nitrogen and hydrogen. The subgrid boiling model accurately captures the contributions to heat transfer from the generation of bubble nuclei, growth, and interaction of the bubbles in the microlayer as well as quenching of the boiling surface following bubble departure. It was adapted for cryogenic fluids using thermodynamic scaling concepts, considering nondimensional pressures and temperatures that are scaled by the corresponding critical values for the fluid. The boiling model was demonstrated for line chilldown in liquid nitrogen. The predicted wall temperature at which quenching occurs was close to the test data for liquid nitrogen, while the slope of the temperature curve after quenching is initiated shows a steeper variation than the test data. Simulations were also performed for liquid hydrogen. Chilldown times in liquid hydrogen are much more rapid due to higher heat transfer in the film boiling regime, and accurately modeling the impact of turbulent heat transfer was found to be important. Furthermore, due to the much colder fluid temperatures in liquid hydrogen, it is critical to model the variable thermal properties of the solid material.

Mitigating effect of chitosan-coated zinc oxide nanoparticles on cryopreservation-induced DNA damage in human spermatozoa

Zinc, an essential micronutrient, is an important mediator of sperm function. Supplementation of zinc oxide nanoparticle (ZnONPs) to semen cryopreservation medium has shown beneficial effects on sperm function, mainly due to its antioxidant and membrane stabilization properties. However, the ZnONPs are known to be membrane impermeable. In the current study, we explored the beneficial properties of membrane permeable zinc oxide nanoparticles on semen cryopreservation outcome. For the study, 52 liquefied human ejaculates were cryopreserved with chitosan-coated ZnONPs and stored in liquid nitrogen for one week. Samples were thawed and assessed for the sperm functional characters and DNA integrity. Significantly higher motility (P < 0.05), prolonged survival (P < 0.05) and lower DNA damage (P < 0.05) was observed in spermatozoa of semen samples cryopreserved with chitosan-coated ZnONPs. In conclusion, the presence of chitosan-coated ZnONPs in the ejaculate prior to cryopreservation increases the survival and decreases DNA damage without compromising with the functional competence of spermatozoa.

Layer-dependent evolution of electronic structures and correlations in rhombohedral multilayer graphene.

The recent discovery of superconductivity and magnetism in trilayer rhombohedral graphene (RG) establishes an ideal, untwisted platform to study strong correlation electronic phenomena. However, the correlated effects in multilayer RG have received limited attention, and, particularly, the evolution of the correlations with increasing layer number remains an unresolved question. Here we show the observation of layer-dependent electronic structures and correlations-under surprising liquid nitrogen temperature-in RG multilayers from 3 to 9 layers by using scanning tunnelling microscopy and spectroscopy. We explicitly determine layer-enhanced low-energy flat bands and interlayer coupling strengths. The former directly demonstrates the further flattening of low-energy bands in thicker RG, and the latter indicates the presence of varying interlayer interactions in RG multilayers. Moreover, we find significant splittings of the flat bands, ranging from ~50 meV to 80 meV, at 77 K when they are partially filled, indicating the emergence of interaction-induced strongly correlated states. Particularly, the strength of the correlated states is notably enhanced in thicker RG and reaches its maximum in the six-layer, validating directly theoretical predictions and establishing abundant new candidates for strongly correlated systems. Our results provide valuable insights into the layer dependence of the electronic properties in RG and demonstrate it as a suitable system for investigating robust and highly accessible correlated phases.

Pine Needle of Pinus koraiensis (Siebold & Zucc) Essential Oil Through Liquid Nitrogen Quick-Freezing Assisted Solvent-Free Microwave Extraction Process for Antibacterial Application.

This study investigates the composition and antibacterial properties of essential oil extracted from Pinus koraiensis (Siebold & Zucc) pine needles using a liquid nitrogen freezing treatment combined with solvent-free microwave extraction (LNSFM). The aim is to develop a low-energy, high-efficiency extraction method for conifer essential oils, analyze their chemical composition, and evaluate their antibacterial efficacy. Pine needle samples were frozen with liquid nitrogen and subsequently crushed. The essential oil was extracted using solvent-free microwave technology. A single-factor test and response surface methodology were employed to optimize extraction parameters. The extraction efficiency of LNSFM was compared with traditional methods through kinetics, and the essential oil components were analyzed using gas chromatography-mass spectrometry (GC-MS). The antibacterial activity of the extracted volatile oil was tested against Escherichia coli and Staphylococcus aureus. LNSFM proves to be a green and efficient extraction method suitable for obtaining volatile oils from pine needles, which demonstrate significant antibacterial properties.

CSIG-01. DECREASING EXPRESSION OF TRAF PROTEINS WITH INCREASING MALIGNANCY WITH LOWEST EXPRESSION IN IDH-WILDTYP GLIOBLASTOMA

Abstract The tumor necrosis factor receptor-associated factors (TRAF) are cytoplasmatic adapter proteins that can interact directly with the intracellular domains of cell surface receptors, such as the TNF receptor superfamily. TRAFs are thus involved in cellular processes like proliferation or apoptosis. Seven members are known; all expressed in the cytosol of various cell and tissue types. Increased levels of TRAF4 in GBM tissue are related to cell proliferation and migration. About 25 % of grade I meningioma show mutations in TRAF7, which are associated with a lower risk of malignant transformation. Therefore expression patterns of all seven TRAF members are evaluated in different glioma grades. Following tumor samples were obtained during neurosurgery and shock frozen in liquid nitrogen: peritumoral tissue, astrocytoma and oligodendroglioma (G2, G3) and glioblastoma (primary and recurrent). Transcription rate of TRAF1-7 was measured via qPCR. Correlation of TRAF expression level and patient overall survival was evaluated using TCGA datasets of the TCGA-LGG” and “TCGA-GBM” projects. With the exception of TRAF5, a decreased mRNA level with increasing malignancy could be found for all TRAFs (TRAF1 p=n.s.; TRAF2 p=0.0026; TRAF3 p&amp;lt;0.0001; TRAF4 p=0.0021; TRAF6 p&amp;lt;0.0001; TRAF7 p&amp;lt;0.0001). IDHwt glioblastoma showed significant lower expression level compared to IDHmut glioblstoma in all TRAFs except for TRAF1 (TRAF2 p&amp;lt;0.0001; TRAF3 p=0.0346; TRAF4 p&amp;lt;0.0001; TRAF6 p=0.0447; TRAF7 p=0.0081). TRAF5 again showed a reverse effect (p=0.0065). Correlation of TRAF expression level in low grade glioma and patient survival revealed longer overall survival with low TRAF1,2,4 and TRAF5 expression (p&amp;lt;0.0001, p= 0.0178, p=0.0307, p&amp;lt;0.0001). No difference in survival rate in high grade glioma could be found.

First Report of Pepper Chlorosis-Associated Virus in Burdock (Arctium lappa) in Korea.

Burdock (Arctium lappa) is a fiber-rich root vegetable widely used in Asian cuisine with many health benefits. In July 2023, two burdock leaf samples showing viral symptoms, such as yellowing and interveinal chlorosis, were collected from a field in Daegu, South Korea, with an incidence rate of about 10%. The samples were pooled, ground with liquid nitrogen, and total RNA was extracted using a Maxwell® 16 LEV Plant RNA Kit (Promega, Madison, USA). A cDNA library was constructed using TruSeq Standard Total RNA with Ribo-Zero (Illumina, San Diego, USA) and sequenced on an Illumina NovaSeq 6000 (BIOTO, Daejeon, Korea) with 100 bp paired-end reads. Of the approximately 84 million reads generated, about 61 million clean reads were identified using Trimmomatic 0.39 with default parameters. Subsequently, Trinity 2.13.0 was used for de novo assembly, resulting in 179,910 contigs, which, when annotated as previously described (Bak et al., 2024), revealed the presence of tomato spotted wilt virus (TSWV) and pepper chlorosis-associated virus (PepCaV). Three PepCaV-related contigs, representing a near-complete genome, were submitted to NCBI GenBank (PP502423-PP502425). BLASTn analysis showed 95.21% (7275/7641 bp), 95.89% (1680/1752 bp), and 96.18% (1461/1519 bp) identities with the L, M, and S segments of the PepCaV isolate Higashitsuno_2021 (LC719619-LC719621), respectively. RT-PCR was performed to confirm the presence of viruses using specific primers for PepCaV (5'-CACCTTGATTATAGACATGACAG/GTTCTCAAATCTTCCCAATCG-3') targeting the coat protein region, and TSWV (5'-GCAACAACTTGCAAGAAGATG/CATGACCTTCAGAAGGCTTG-3'; Kim et al., 2021). Initial results showed both samples were positive for TSWV, and one was positive for PepCaV. Additionally, 26 symptomatic and 8 asymptomatic samples were collected from the same field. PepCaV was positive in 3 samples, TSWV in 12, and TSWV+PepCaV in 11 by RT-PCR. All asymptomatic samples were negative. Leaves infected with PepCaV, whether solely or co-infected with TSWV, initially exhibited interveinal chlorosis and vein contraction on one side of the main vein (Fig. S1). In plants infected with PepCaV alone, these symptoms were mild or less noticeable in the initial phases. The majority of PepCaV-infected samples were co-infected with TSWV, during which symptoms appeared more severe. Following this, an amplicon, derived from the sample that initially tested positive for PepCaV in the first RT-PCR was cloned using the All in OneTM Cloning Kit (BioFact, Daejeon, Korea) and sequenced by Bionner (Daejeon, Korea). The resulting sequence, submitted to NCBI GenBank (PP928956), demonstrated 96.87% (805/831 bp) identity with the PepCaV isolate Higashitsuno_2021 (LC719600). Moreover, sap inoculation was performed on A. lappa, Nicotiana benthamiana, N. clevelandii, N. debneyi, N. rustica, N. tabacum, Chenopodium amaranticolor, and C. quinoa, but no transmission was identified in any case. PepCaV, recently identified and likely belonging to the genus Ophiovirus within the family Ophioviridae, is known to infect pepper and tobacco (Shimomoto et al., 2023; Wang et al., 2024). This is the first report of PepCaV in Korea and the first identification of burdock as a natural host. Although studies on its vectors and pathogenicity are lacking, PepCaV's presence suggests potential risks. Given the widespread cultivation of burdock in Korea, PepCaV could significantly impact local agriculture by affecting crop yield and health.

Solid–Liquid Diffusion Stresses Leading to Voiding

AbstractThis paper discusses cavitation within a two-phase solid–liquid enclosed system due to interdiffusion. This mechanism is discussed within the context of solid–liquid interdiffusion bonding for metal systems and the voids which are caused by this mechanism. A case study composed of liquid (Sn), Ni3Sn4, and (Ni) phases was used. The mechanical tension and bubble volume resulting from the mechanically enclosed system during isothermal solidification at 250 °C were calculated using a fitted 1D growth model coupled with thermodynamics. Thermodynamic energy calculations showed that it becomes favorable for cavitation after 6 seconds for a starting liquid pocket of 5 µm3. The critical pressure for this cavitation was − 0.029 GPa. The volumetric change for the reaction was determined to be − 12.3 vol pct by a partial molar volume balance. While the volumetric change determined by the thermodynamics found − 7.2 vol pct. The likely presence of unwettable inclusions in non-pure liquids would circumvent this cavitation mechanism, even though cavitation conditions are present. Meaning cavitation for these systems can only be expected when the liquid metal purity is sufficient. Lastly, the bubble growth is attributed to a combination of thermodynamic bubble growth and Kirkendall vacancies.

Preparation of tannic acid-based recyclable adhesive with high adhesion property, low curing temperature, and environmental tolerance

Tannin-based adhesives have demonstrated promise in decreasing dependence on petrochemical resources linked to formaldehyde-based resins. However, current tannin-based adhesives face challenges due to the incorporation of expensive or toxic reagents such as isocyanate, epoxy, and formaldehyde, as well as the inability to be recycled. This study presents a simple and eco-friendly approach for producing a tannic acid-based recyclable adhesive (TA-BVB) by employing tannic acid and 1,4-butanediol divinyl ether through acetal reactions. The resulting adhesive can be cured at a low temperature of 70℃ and demonstrated high bonding strength on wood and aluminum sheets, measuring 4.45 MPa and 5.44 MPa, respectively. Notably, the adhesive maintained its adhesion strength even under harsh conditions, including high temperatures (100℃), liquid nitrogen (-196℃), and exposure to various solvents. Moreover, the adhesive showcased excellent reusability, retaining over 100 % and 86 % of bonding strength after the first and second rounds of hot pressing, respectively. This adhesive can be repaired using infrared laser irradiation and displayed remarkable mold resistance. This research underscores the potential of tannic acid in developing environmentally friendly, high-performance, recyclable adhesives with versatile applications.

Double Gold/Nitrogen Nanosecond-Laser-Doping of Gold-Coated Silicon Wafer Surfaces in Liquid Nitrogen

A novel double-impurity doping process for silicon (Si) surfaces was developed, utilizing nanosecond-laser melting of an 11 nm thick gold (Au) top film and a Si wafer substrate in a laser plasma-activated liquid nitrogen (LN) environment. Scanning electron microscopy revealed a fluence- and exposure-independent surface micro-spike topography, while energy-dispersive X-ray spectroscopy identified minor Au (~0.05 at. %) and major N (~1–2 at. %) dopants localized within a 0.5 μm thick surface layer and the slight surface post-oxidation of the micro-relief (oxygen (O), ~1.5–2.5 at. %). X-ray photoelectron spectroscopy was used to identify the bound surface (SiNx) and bulk doping chemical states of the introduced nitrogen (~10 at. %) and the metallic (&lt;0.01 at. %) and cluster (&lt;0.1 at. %) forms of the gold dopant, and it was used to evaluate their depth distributions, which were strongly affected by the competition between gold dopants due to their marginal local concentrations and the other more abundant dopants (N, O). In this study, 532 nm Raman microspectroscopy indicated a slight reduction in the crystalline order revealed in the second-order Si phonon band; the tensile stresses or nanoscale dimensions of the resolidified Si nano-crystallites envisioned by the main Si optical–phonon peak; a negligible a-Si abundance; and a low-wavenumber peak of the Si3N4 structure. In contrast, Fourier transform infrared (FT-IR) reflectance and transmittance studies exhibited only broad structureless absorption bands in the range of 600–5500 cm−1 related to dopant absorption and light trapping in the surface micro-relief. The room-temperature electrical characteristics of the laser double-doped Si layer—a high carrier mobility of 1050 cm2/Vs and background carrier sheet concentration of ~2 × 1010 cm−2 (bulk concentration ~1014–1015 cm−3)—are superior to previously reported parameters of similar nitrogen-implanted/annealed Si samples. This novel facile double-element laser-doping procedure paves the way to local maskless on-demand introductions of multiple intra-gap intermediate donor and acceptor bands in Si, providing related multi-wavelength IR photoconductivity for optoelectronic applications.

Crude Garden Cress Seed Oil (Lepidium sativum Linn.) Enhances Post-Thawed Boar Sperm Quality

This study aimed to examine the effects of crude garden cress seed oil (CGCSO) on frozen–thawed boar sperm qualities. Semen ejaculates (n = 12) were collected and further divided into six equal aliquots based on CGCSO concentrations (0, 0.5, 1, 1.5, 2, and 2.5% v/v) in the freezing extender. Semen samples were processed and cryopreserved utilizing the traditional liquid nitrogen vapor technique. Subsequently, semen samples were thawed in a thermos with warm water at 50 °C for 12 s and evaluated for sperm morphology using scanning electron microscopy, sperm motility using a CASA, sperm viability, acrosome integrity, mitochondrial function, MDA level, total antioxidant capacity (TAC), glutathione peroxidase (GSH-Px), and catalase (CAT) activity. The results indicated that 1% CGCSO resulted in superior post-thaw sperm characteristics, including enhanced sperm morphology, motility, viability, acrosome integrity, and mitochondrial function. Particularly, the total motile sperm increased by 16.5%, progressive motile sperm increased by 13.0%, viability improved by 15.1%, acrosome integrity increased by 14%, and mitochondrial function improved by 14.1% compared to the control group. CGCSO treatment at 1% and 1.5% exhibited the lowest level of MDA (45.73 ± 11.2 and 45.73 ± 11.3 µmol/L, respectively) compared to the other groups. The CGCSO-supplemented groups showed higher values of TAC, GSH-Px, and CAT than the control group but not significantly.

Nano-Pd/SiO2 aerogel catalyst prepared via ambient pressure drying process using perlite powder in hydrogenation and cross-coupling reactions

Perlite, a cheap silica source with abundant reserves in countries such as Türkiye, China, and Greece, was used to produce nano Pd-doped silica aerogel powder for the first time in this study. The microstructure and morphology of the prepared silica aerogel powder were examined using SEM, FE-SEM, and TEM. The phases of the silica aerogel powders were analyzed via XRD (X-ray Diffraction) technique. The chemical bonding of the surface modifier with aerogels was analyzed by Fourier transform infrared spectroscopy (FTIR, Spectrum RX-1, Perkin Elmer). Surface areas, pore volumes, distributions, and particle sizes of the alumina-silica-based aerogel powders with a porous structure were measured using a Micromeritics/ASAP 2020 brand BET (Brunauer, Emmet, and Teller) device in a liquid nitrogen gas environment at 77K.The efficiency of this nano Pd-doped silica aerogel powder was investigated as a heterogeneous catalyst for well-known transformations in organic synthesis, such as alkene hydrogenation and cross-linking reactions. The results indicated that the developed method is chemoselective, reducing only carbon-carbon multiple bonds without affecting C-N or C-O multiple bonds, such as carbonyl and nitrile. The effectiveness of the newly developed catalyst was also investigated in Heck and Suzuki-Miyaura reactions, yielding the targeted products with high efficiency.Thus, an inexpensive, economical, and environmentally friendly method has been developed that is potentially applicable in the hydrogenation and cross-coupling reactions of alkenes.

Modeling the effect of superconductor properties on sensitivity and responsivity of superconducting nanowire single photon detector

Superconducting nanowire single photon detector (SNSPD) is a leading candidate for applications requiring the fundamental limit of light detection at high detection rates. While SNSPD technology employing nanowires from conventional low temperature superconducting detectors is mature with several commercial solutions, other material options with higher transition temperature approaching liquid nitrogen with faster signal responses are actively being explored. In this context, we develop a comprehensive model that predicts the final potential response from an SNSPD incorporating several physical and material aspects. A phase diagram of photon detection is developed that describes the latching phases and the photon sensitivity as a function of biasing current and temperature for both low temperature and high temperature superconductors. On the one hand, while low temperature superconductors are observed to be more sensitive than high temperature superconductors (HTSs) under any given biasing condition, a biasing window for a single photon detection with HTS nanowires is identified. On the other hand, HTS nanowires demonstrate three orders of magnitude faster response times than the low temperature superconductor nanowire at the same biasing condition, making it uniquely suited for several practical applications.