Temperature Shock Research Articles

Orientation-dependent phase transition pathways of single-crystal nickel over large shock range

The response of single crystals to increasing shock strength involves complex phase transition processes from solid-solid to solid-liquid phases. However, it is not yet fully understood how these phase transitions occur along different crystallographic orientations, and what the dominant micro-mechanisms are at different shock stages. To fill this knowledge gap, non-equilibrium molecular dynamics simulations are performed to explore the dynamic phase-transition characteristics of face-centered cubic Ni single crystal over a large shock strength range of 0–350 GPa. The orientation-dependent phase transition in single-crystal Ni is examined through three typical shock directions: [001], [011], and [111], and a phase-transition locus map is established. The results show that the shock compression of single-crystal Ni undergoes four response stages: (I) elasticity, (II) plasticity, (III) partial melting, and (IV) complete melting. The shock orientation plays a crucial role in the shock wave structure, Hugoniot, microstructure evolution, and shock melting behavior. The [001] shock direction maintains a single-wave structure and exhibits a shear stress superelasticity. However, the [011]/[111] orientations undergo a single-double-single wave transformation, and an interesting U-shape transition wave is identified along the [111] orientation due to its unique progressive plasticity. Superheating and cold melting phenomena are observed along the [001] and [011]/[111] orientations, respectively. The differences in the critical melting temperature and threshold shock pressure along different orientations are up to ∼3000 K and ∼80 GP. Atomic-structure analysis reveals that due to the Bain path, FCC→BCC (BCT) is the dominant solid-solid phase transition along the [001] orientation, and the dislocation slips are limited in a narrow shock window. Melting nuclei emerge, grow, and coalesce homogeneously on the BCC (BCT) substrate, leading to the superheating phenomenon. In contrast, a dynamic process involving shock melting and recrystallization is observed along the [011]/[111] orientations, which finally results in the coexisting of the solid and liquid phases. Heterogeneous melting, marked by mixed phases, is the most distinctive feature in the [011]/[111] orientations, which is responsible for the cold melting phenomenon. Our study shed light on the shock-induced phase transitions of FCC single crystal, which may offer insight into understanding the complex polycrystalline.

Molecular, enzymatic responses and in vitro embryonic developmental competency of heat-shocked buffalo embryos co-cultured with granulosa cells monolayer

The present study was designed to establish a suitable alternative approach to mitigate the adverse effect of high culture temperature on in vitro embryo development and the related molecular response in buffalo. Pre-cultured granulosa cells (GCs) were used as a monolayer during in vitro embryo culture until day 8 (day of fertilization = D0). Post fertilization, presumptive embryos were randomly assigned into two culture conditions: embryos cultured in the presence of GCs monolayer under normal culture temperature (N: 38.5 °C; GEN group) or heat shock (H: 40.5 °C; GEH group) and their counterpart groups of embryos cultured without GCs (EN and EH groups). Additionally, two groups of GCs monolayer were cultured without embryos up to day 8 under 38.5 °C (GN) or 40.5 °C (GH) for further spent culture media enzymatic analyses. Heat shock was administered for the first 2 h of culture then continued at 38.5 °C until day 8. The results indicated that under heat treatment, GCs enhanced (P ≤ 0.05) embryo cleavage and development (day 8) rates, which were comparable to the embryos cultured at 38.5 °C. On the molecular level, blastocysts of the GEH group showed similar expressions of metabolism-regulating genes (CPT2 and SlC2A1/GLUT1) and an antioxidant gene (SOD2) when compared to the blastocysts of the EN group. The relative expression of HSP90 was significantly up-regulated under heat shock and/or co-culture conditions. However, HSF1 expression was increased (P ≤ 0.05) in the GEH group. No statistical differences were observed among the study groups for the pluripotency gene NANOG, and stress resistance transcript NFE2L2. Regarding the enzymatic profile, the concentrations of SOD, total protein, and MDA were decreased (P ≤ 0.05) in the GEH group compared to the cultured GCs without embryos (GH group). In conclusion, GCs as a monolayer have a beneficial impact on alleviating heat stress at the zygote stage through the regulatory mechanisms of metabolic activity, defense system, and heat shock response genes.

Prevalence of subclinical abortions in cows due to mycotoxicosis

The article presents data on the distribution and seasonal dynamics of subclinical abortions in cows with mycotoxin poisoning, particularly zearalenone. Subclinical abortion is a common phenomenon among cows in dairy farms and causes significant economic losses due to multiple unsuccessful inseminations, reduced animal productivity, and premature culling. The research aimed to study the seasonal fluctuations of hidden abortions in cows and the influence of the method of keeping in the conditions of feed contamination with microscopic fungi and their toxins. To diagnose hidden abortions, cows were diagnosed with the pregnancy on the 32nd day after insemination. When pregnancy was confirmed, the animals were examined for 92 days. At the same time, if the pregnancy was not confirmed, it was considered that an abortion had occurred. Seasonal fluctuations of subclinical abortions were established - the most significant number (up to 13.6 %) was diagnosed at the end of spring, associated with many animals entering the hunt after the transit period. It is also important that at that time, the number of mycotoxins in feed reached record values, which led to abortions due to toxic effects on the organs of the reproductive system in particular and the body in general. A large number of abortions (11.2 %) in the summer season was also confirmed. At the same time, animals kept free all year received a similar diet containing mycotoxins. At the same time, a concomitant negative factor was temperature shock at this time of year. This whole complex of reasons led to subclinical abortions followed by the resorption of the fetus. Sonographically, areas of reduced echogenicity of the uterus in cows after abortions were detected, which is evidence of the development of subclinical endometritis, confirmed by the uterus's heterogeneous echogenicity. In infertile animals, the presence of follicles with cavities and small yellow bodies that did not extend beyond the surface of the ovary was established sonographically. This indicates a hypofunctional state and impaired folliculogenesis and luteogenesis.

Temperature shocks and industry earnings news

Climate scientists project rising average temperatures and increasing frequency of temperature extremes. We study how extreme temperatures affect corporate profitability across different industries and whether sell-side analysts understand these relationships. We combine granular daily data on temperatures across the continental U.S. with locations of public companies’ establishments and build a panel of quarterly firm-level temperature exposures. Extreme temperatures significantly impact earnings in over 40% of industries, with bi-directional effects that harm some industries while others benefit. Analysts and investors do not immediately react to observable intra-quarter temperature shocks, though earnings forecasts account for temperature effects by quarter-end in many industries.

Influence of a temperature shock on the synthesis efficiency of surfactants by <i>Rhodococcus pyridinivorans</i> 5Ap bacteria

It was found that the synthesis of surfactants by R. pyridinivorans 5Ap bacteria can be increased by exposing them to a short temperature shock (55 °C for 20 minutes) after 24 hour cultivation in a minimal medium containing molasses (3 %) and hexadecane (2 %) (9 % increase in the emulsification index). Gene activation encoding global regulators of cell metabolism, including those performing a protective function under stress, was recorded in this cultivation mode. In particular, the mRNA amount determining the synthesis of the alternative transcription factor SigH increased 90.8 times and containing in the promoters its binding sites fmdB cochaperone – 59.3 times, hsp22.5 chaperone – 81.1 times, and the trxB gene encoding thioredoxin reductase – 73.1 times. In addition, it was shown that the transcriptional activation of groEL1, groEL2 and dnaJ genes determining the synthesis of heat shock proteins was 2.2, 2.6 and 4.4 times, respectively. The obtained results suggest that an increase in the alternative factor sigma H synthesis, which activates protective cellular metabolism, as well as structural, heat shock proteins under short temperature stress, leads to an increased production of surfactants, which can be used to optimize the synthesis of these secondary metabolites for biotechnological use.

Research on the Application of Domestic High-Modulus Carbon Fiber/Epoxy Composites to Solar Panels for Solar Arrays

Based on the new high-modulus carbon fiber CCM40J-6k, which is the critical raw material of a solar panel, the molding process of a mesh face sheet combined with epoxy resin, the overall mechanical performance of a mesh face sheet combined with aluminum honeycomb, the compatibility with polyimide insulation film + solar cell circuit, and the space environment adaptability must pass a test verification and assessment as the premise for large-scale orbit applications. Therefore, based on the traditional carbon fiber M40JB-6k as a reference, a systematic verification project was conducted to apply the CCM40J-6k carbon fiber composite at the process, component, and assembly levels. Six aspects of testing and verifying items were conducted, including mechanical properties under room temperature and thermal shock conditions, bonding force of mesh nodes, comparison of the adaptability of domestic and imported carbon fiber substrates to high–low temperature alternation, the ability of domestic carbon fiber substrates to adapt to the thermal environment after laying solar cell circuits, and in-orbit lifespan of solar panels. Based on the verification results, the mechanical properties of the substrate are the same as those of the imported M40JB-6k, and the actual molding process for M40JB-6k can be utilized. Sample pieces of the substrates can withstand the thermal shock and thermal cycling tests. The bending stiffness of the sample pieces before and after the tests is 3.5%~9.6% higher, and the bending strength is 4.2%~7.2% lower. The tensile strength of mesh nodes made of domestic carbon fiber is 18.9% higher than that of mesh nodes made of imported carbon fiber. The CCM40J-6k substrate is similar to triple-junction GaAs solar cells. The change rates of the open-circuit voltage and the short-circuit current of solar panels based on domestic carbon fiber after fatigue thermal cycling with 2070 cycles are 0.55% and 0.24%, respectively. The above results indicate that the comprehensive performance of the domestic carbon fiber CCM40J-6k meets the requirements and can be applied to solar panels for solar arrays.

Tracing the elimination of reentry spiral waves in defibrillation: Temperature effects

The presence of spiral waves in cardiac tissue causes ventricular fibrillation (VF). Clinical studies have demonstrated that reducing the blood temperature to hypothermia can improve the success rate of electrical defibrillation when VF occurs. In this paper, the Hodgkin-Huxley-style model is used to simulate the effects of temperature and electric shock on the spiral waves present in mammalian tissues, and the phase singularity (PS) identification methods are used to track the wave behaviors in network, finally the Luo-Rudy model is used to test the applicability of our results for cardiac tissues. The results show that temperature modulates the optimal parameters for defibrillation: (1) Arnold's tongue structure shows that an alternating electric field close to the tissue natural frequency (e.g.: cardiac sinus rhythm) allows the nodes to be phase-locked or PS directionally drift at a smaller intensity, thus eliminating spiral waves more effectively than a constant electric field. (2) The average node frequency increases with temperature whether the network is synchronized or present spiral waves, and the statistics show that the robustness of electric defibrillation can be enhanced when the tissue is at moderate hypothermia. (3) More interestingly, we define the defibrillation score (DFS) and find that moderate hypothermia is a balance to improves defibrillation success, which may provide some insights for practical defibrillation studies.

Investigation of Perturbations Arising from Temperature Shock with a Symmetrical Arrangement of Flexible Elements of a Small Spacecraft

This paper investigates the effect of a temperature shock on a small spacecraft with symmetrically arranged flexible elements. A two-dimensional thermoelasticity problem is posed. The disturbing effect of temperature shock on a small spacecraft has been determined. The assessment of the main disturbing factors arising from the temperature shock of flexible elements of a small spacecraft was carried out. Approximate dependences were obtained for the components of the displacement vector of the flexible element points. Numerical simulation was carried out for the symmetric scheme of the small spacecraft with two and four flexible elements. The dependence of the inertia force on temperature shock for the simulated small spacecraft at various initial deflections of the flexible element was constructed. Conclusions were drawn about the significance of the temperature shock influence on the dynamics of a small spacecraft. The results obtained were compared with the results of other studies and can be used in solving problems of remote sensing of the Earth and the implementation of gravity-sensitive processes on board small spacecraft.

Investigation of generative high temperature tolerances of some cotton (Gossypium hirsutum L.) varieties

The potential of cotton genotypes to form buds, flowers and bolls is not sufficient to achieve cotton seed yield targets. Despite global warming buds, flowers and bolls that mature in cotton plants must be successfully transformed into products. However, this is related to the generative tolerance of the genotype to high temperature. In study aims to scan the negative effects of high temperature stress on the generative development on cotton varieties registered in Turkey in the last 10 years. The experiment was established in the GAP International Agricultural Research and Training Center trial field in 2020, with 4 blocks according to the Augmented design. Six standards (Tamcot Spnhix, SJU86, AGC208, ST468, ST474, Carmen) and 88 cotton varieties registered in Turkey National Variety List were used as trial material. In this study, high temperature pollen vitality stress index (HTPVSI) and high temperature shedding stress index (HTSSI) properties were investigated. According to the results of the experiments we conducted, it was determined that the HTPVSI values ranged between 0.17-1.26, the HTPVSI averages of the standards were 1.17, and the HTPVSI averages of the genotypes were 0.99. It has been determined that HTSSI values vary between 0.30-1.71. It was determined that the mean HTSSI values of the standards were 0.89 and the genotypes were 1.00. It was determined that there was a wide variation among the genotypes screened for generatively high temperature stress. Using HTSSI and HTPVSI features is recommended as a selection criterion since it is an important trait for screening genotypes in terms of tolerance or sensitivity to generative high temperature stress in cotton plants. In our study, the results were not similar to each other in terms of HTPVSI and HTSSI traits, due to the low share of flower shedding after applying HTSP (High Temperature Shock Practice: 96 hours of uninterrupted exposure to high temperature during generative periods) in the shedding rate. When the examined HTSSI and HTPVSI traits were examined together, no cotton genotypes were found to be generatively tolerant. In terms of sensitivity of genotypes to high temperature, 18 cotton genotypes were found in the medium tolerant group and 25 cotton genotypes were found in the sensitive group.

Microstructure Characterization, Mechanical and Wear Behavior of Silicon Carbide and Neem Leaf Powder Reinforced AL7075 Alloy hybrid MMC’s.

The demanding material quality criteria in the automotive and aerospace industries have recently had an impact on the development of lightweight aluminium alloys. The choice and application of metal-matrix composites as structural materials in this context are known to offer a variety of benefits. These benefits include the ability to combine high elastic modulus, toughness, and impact resistance; minimum sensitivity to change in temperature or thermal shock; durability of the surface is good; moisture absorption leads to the potential issue while minimum exposure which leads to environmental degradation; and improved fabricability with conventional metalworking equipment. Aluminium metal matrix composites (AMMCs) are a potential material for advanced structural, aviation, aerospace, marine, and defence applications, as well as for the automotive sector and other related fields, due to their outstanding combination of qualities. The stir casting procedure is used to create an aluminium metal matrix composite (AMMC), which is the most efficient way to do so. In this study, the aluminium alloy 7075 is strengthened using neem leaf powder and SiC. The Vickers hardness examination method is used to govern the hardness of hybrid composites. Eventually, the mechanical and tribological properties of the composites were assessed, and their relationship to the composites' matching microstructure and wear was addressed.

Reliability Analysis of Flip-Chip Packaging GaN Chip with Nano-Silver Solder BUMP.

Gallium nitride (GaN) power devices have many benefits, including high power density, small footprint, high operating voltage, and excellent power gain capability. However, in contrast to silicon carbide (SiC), its performance and reliability can be negatively impacted by its low thermal conductivity, which can cause overheating. Hence, it is necessary to provide a reliable and workable thermal management model. In this paper, a model of a flip-chip packing (FCP) GaN chip was established, and it was assigned to the Ag sinter paste structure. The different solder bumps and under bump metallurgy (UBM) were considered. The results indicated that the FCP GaN chip with underfill was a promising method because it not only reduced the size of the package model but also reduced thermal stress. When the chip was in operation, the thermal stress was about 79 MPa, only 38.77% of the Ag sinter paste structure, lower than any of the GaN chip packaging methods currently in use. Moreover, the thermal condition of the module often has little to do with the material of the UBM. Additionally, nano-silver was found to be the most suitable bump material for FCP GaN chip. Temperature shock experiments were also conducted with different UBM materials when nano-silver was used as bump. It was found that Al as UBM is a more reliable option.

Thermal management of Ammonia-fed Solid oxide fuel cells using a novel alternate flow interconnector

Ammonia is a promising fuel for solid oxide fuel cells (SOFCs) as it is carbon-free and easy to store at high volumetric energy densities. However, the endothermic decomposition of ammonia in an SOFC stack significantly reduces the temperature at the entrance of the fuel flow, leading to temperature shock and nitriding. Designing a suitable interconnector for the stack to obtain a flatter temperature distribution is an efficient strategy to overcome this problem. This article proposes a novel interconnector design using an alternate flow concept for both fuel and air. A three-dimensional SOFC model was used for the thermal investigation of the proposed design under different operating conditions, including temperature, current, and fuel utilization. The results indicated that the alternate flow design exhibited a 40% lower temperature difference and up to 53 K higher average temperature than a typical cross-flow design. In addition to a flatter temperature profile, the proposed design exhibited a higher ammonia conversion rate than the conventional design, demonstrating its promise for use in robust and efficient ammonia-fed SOFC stacks.

Analysis of clock drift based on a three‐dimensional controlled‐source ocean bottom seismometer experiment

AbstractClock drift is common for the autonomous ocean bottom seismometer, and a technique of linear drift correction is usually used to fix this kind of timing error assuming that the internal clock has constant drift rate during deployment. However, non‐linear component of clock drift has also been found recently. In order to test the behaviours of the clock drift for 19 Chinese ocean bottom seismometers from a three‐dimensional controlled‐source seismic survey, we have analysed two types of differences in direct wave travel‐times, including one from all shots to the ocean bottom seismometer onboard and another one from the nearest two shots on different shooting lines to the ocean bottom seismometer on the seafloor. Comparison of the differences in direct wave travel‐times from seismic data with and without clock drift correction shows that linear drift correction can commendably eliminate them for most of the ocean bottom seismometers, but some large residuals remain for part of the ocean bottom seismometers. These residuals are inferred to be possibly related to the non‐linear component of clock drift caused by the temperature shock during deployment. The non‐linear clock drift usually varies from different ocean bottom seismometers and thus difficult to correct completely and resultantly will influence the timing accuracy somewhat. Hence, higher uncertainties are suggested to assign to the picked travel‐times for the ocean bottom seismometer with possibly larger non‐linear clock drift in the further tomographic modelling and the internal clock for this kind of ocean bottom seismometer should be recalibrated prior to the next experiment if which requires higher timing accuracy.

A low-concentration 2-step synthesized spiroquaternary ammonium salt electrolyte for commercially stable pouch-type supercapacitors

Currently, non-aqueous, stable supercapacitors manufactured for commercial use require an environmentally benign and economically viable electrolyte synthesis technique. Spiro-based salts dissolved in organic solvents are known to have smaller ion-size, which facilitate charge transport during storage at varying temperatures and preserve storage efficiency over time. Previously, the synthesis of spirobased salt syntheses via complex multistep procedures involving toxic chemical solvents and low yields have been reported. The current work proposes a modified water-based ion-exchange process coupled with an innovative purification step that results in improved yield. In addition, the synthesized spiro-(1,1′)-bipyrrolidinium tetrafluoroborate (SBPBF4) salt mixed in an optimized organic solvent blend produced a dilute (0.2 M) electrolyte with its ionic conductivity comparable to commercially recognized, higher concentrated ionic salt electrolytes (3 M). Using the dilute SBPBF4 electrolyte, the pouch-type (PoC-SBF4) devices were operated up to 3 V.An average rated capacitance of 300 F was demonstrated with up to 43 W h kg−1 specific energy and 1 kW kg−1 of maximum deliverable power. After 10,000 continuous charge-discharge cycles, the device retained 97 % of its capacitance at an applied current of 5 A.Notably, the extreme temperature shock tests at −70 °C also demonstrated ~60 % capacitance retention after subjecting the device to cycling at 5 A for 72 h (3 days) to simulate extreme weather conditions for potential integration with renewable energy, mobility, or deep space applications.The water-based ion exchange step and the use of dilute electrolytes reduces the overall cost of manufacturing supercapacitor when scaling up the production process. The results presented provides a critical evaluation of the criteria for developing robust, stable, and low-cost supercapacitors from laboratory to large-scale manufacturing.

A trimode textile designed with hierarchical core-shell nanofiber structure for all-weather radiative personal thermal management

Radiative thermal management textile regulates reflectivity, emissivity, and transmissivity to achieve different thermal functions without any electrical or chemical energy consumption. Despite significant advances, achieving effective radiative cooling in high humidity weather and improving textile resistance to temperature shocks remain challenges. Here, we exploit a novel trimode all-weather personal thermal management textile (TAWT) that combines radiative cooling, solar heating, heat storage and release of phase change. High solar reflectance of 96.6% and Mid-infrared emittance of 93.2% of TAWT in cooling mode generate a temperature drop of 13.1℃ and 9.2℃ compared to bare skin and traditional textile. The unique solar absorptivity of 82.0% and low infrared emissivity of 67.8% in heating mode prevents overcooling by 10.9℃ compared with bare skin. The large heat enthalpy density of 81.1 J/g created an additional temperature drop of 3.9℃ in high humidity weather, which effectively makes up for the shortage of radiative cooling capacity. Meanwhile, the heat storage and release of phase change enhance the resistance of the human body to temperature shocks. In addition to thermal management capabilities, TAWT also exhibits favourable wearability. Given these attractive advantages, TAWT would offer advance insight for the development of functional textiles.

Climate vulnerability and fertilizer use – panel evidence from Tanzanian maize farmers

ABSTRACT Chemical fertilizers can significantly improve agricultural productivity but their environmental sustainability is much debated. This paper contributes to a growing body of research on the drivers of chemical fertilizer use under climate vulnerability. We study the impact of climate risk (measured as rainfall abundance, rainfall variability, temperature and temperature shock) on fertilizer use by Tanzanian maize farmers using Probit regression analysis on spatially disaggregated agronomic panel survey data for the years 2016 and 2017. Our results show that fertilizer use is extremely sensitive to climate risks, even when accounting for actually observed input prices, the main contribution of this study. Our findings suggest that as the climate crisis escalates with erratic rainfalls and warmer climate, chemical fertilizers will become increasingly less reliable to ensure food security for a growing population as farmers’ fertilizer adoption decision is highly responsive to climate variability. This lends support to arguments that perfunctory promotion of chemical fertilizers is at odds with sustainable intensification agricultural policies.

Manufacturing of individualized sensors: Integration of conductive elements in additively manufactured PBT parts and qualification of functional sensors

AbstractThe growing variety of product variants requires smaller and more complex parts with increasing functionality. Additively manufactured parts with integrated, freely arranged standard electrical components would allow application-specific design and high integration density. Such systems can be used as proximity sensors for industrial applications, acoustic sensors for hearing aids, or ultrasonic sensors for food inspection, as well as integrated analog-to-digital converters for standard sensors or wear detection sensors in tools. Preliminary studies have shown that a hybrid manufacturing process can be used to additively manufacture such geometrically individualized sensors. In the approach chosen here, standard electrical components are integrated into housings produced using the ARBURG Plastic Freeforming (APF) process. The housing material used is a PBT granulate, which is a standard material in the electronics industry. The integrated electrical components are electrically connected using a silver conductive paste and are generated using a jet dispensing valve. Based on the hybrid manufacturing process, it is possible to produce geometrically customizable industrial proximity sensors in one production step. In this publication, various connection options were investigated and design guidelines for the microdispensing of silver paste were derived. In addition, twelve functional sensors were manufactured and subjected to three industrial standard quality tests. Five out of six passed the temperature shock test, three out of four passed the humidity-heat test, and two out of two passed the vibration and shock test. Thus, the proof of concept was principally provided that the investigated connection options are suitable to produce individualized electronic sensors.

Investigating the Temperature Shock of a Plate in the Framework of a Static Two-Dimensional Formulation of the Thermoelasticity Problem

The paper investigates the stress–strain state of a homogeneous rectangular plate after a temperature shock. It is believed that the plate is the first approximation of the solar panel model of a small spacecraft. To study the stress–strain state of the plate, a two-dimensional thermoelasticity problem is posed. The problem has a static formulation, since it does not take into account the dynamics of the plate’s natural oscillations. These oscillations affect the stress–strain state through the initial deflection of the plate at the time of the temperature shock. This deflection changes the parameters of the temperature shock and does not allow the use of a one-dimensional formulation of the thermoelasticity problem. As a result of solving the static two-dimensional thermoelasticity problem, approximate solutions are obtained for the components of the plate point’s displacement vector after the temperature shock. An approximation of the temperature field is presented. A numerical simulation is carried out. The correspondence of the obtained approximate analytical dependencies of the components of the plate point’s displacement vector to the numerical simulation data is analyzed. The proposed method can be used to assess the significance of the influence of the small spacecraft’s solar panels temperature shock on the dynamics of its rotational motion.

티타늄 소재 극저온 가공 시 극미량 윤활 조건에 따른 가공 특성 분석 연구

Titanium alloys are used in various industries due to their superior mechanical strength and corrosion resistance. However, titanium is classified as a difficult-to-machine material due to its low thermal conductivity that consequently causes poor tool life. In this study, cryogenic+MQL milling was performed to improve the machinability of Ti-6Al-4V; a cryogenic coolant and a minimum quantity fluid were sprayed simultaneously. The machinability was analyzed according to the cooling and lubrication conditions, focusing on the cutting force and tool wear. When the minimum quantity fluid was injected using two nozzles during cryogenic machining, the cutting force remained low despite the increase in machining distance due to the effective lubrication. The average cutting force at the long machining distances (82-86 passes) was 14.8% lower than that under the wet condition. The tool wear progressed without chipping, and the flank wear length was 55.5% lower than that of the wet machining because the cryogenic cooling and minimum quantity lubrication reduced the tool temperature, friction, and thermal shock.

Temperature shocks and stock returns: evidence from major markets

ABSTRACT Global temperatures have increased at a historically unprecedented pace. The paper finds the negative impact of high temperatures on global stock prices and offers evidence on three channels that justify this impact, i.e. the effect on firms’ assets, on investments, and on leverage costs. The results encourage market stakeholders to consider the role of temperature shocks in their market involvement.