Volume Compressibility Research Articles

Studies of a Mechanically Pumped Two-Phase Loop with a Pressure-Controlled Accumulator Under Pulsed Evaporator Heat Loads

As avionics become more power dense, electronic device cooling has become a significant barrier to aircraft integration. A mechanically pumped two-phase loop (MPTL) is a thermal subsystem that enables near isothermal evaporator operation, which is desirable for electronics cooling. The goal of this study was to integrate an MPTL with a pressure-controlled accumulator and model a predictive control technique to demonstrate improvements for transient, isothermal evaporator operation for MPTLs under pulsed evaporator heat loads. The model predictive controller enables active control of MPTL compressible volume, which has not been demonstrated for pulsed evaporator heat loads. Experimental data were collected to validate a representative numerical model. A pressure-controlled accumulator was added to an MPTL to experimentally characterize the system thermodynamic response for three pulsed evaporator heat loads. Two statistical methods were used to assess the numerical model agreement with the experimental results. Under pulsed evaporator heat loads, the mean percent error agreed within 3.45% and the mean average percent error agreed within 0.74% for the three pulsed evaporator heat loads. Finally, a traditional proportional–integral (PI) controller and an advanced model predictive controller were developed and integrated into the validated numerical model. Both control methods were evaluated for an expanded set of evaporator heat load profiles to analyze transient behavior. For evaporator heat profiles with high heat transfer rates, the model predictive controller can maintain a target ±2 K refrigerant temperature at the evaporator exit throughout the evaporator heat load duration, whereas the PI-controlled MPTL cannot. Through this work, active control of a pressure-controlled accumulator within an MPTL is shown to improve refrigerant isothermal (±2 K) operation when compared to a traditional control technique.

Comparative analysis of flexural strength prediction in SFRC using frequentist, Bayesian, and Machine Learning approaches

Steel fiber reinforcement significantly enhances the flexural strength of concrete, which is vital for structural integrity. Annex L of the new Eurocode 2 classifies steel fiber-reinforced concrete by its flexural performance, aiding engineers in designing resilient structures. This study investigates the flexural behavior of steel fiber-reinforced concrete (SFRC) using three data-driven methodologies: Frequentist Inference (FI), Bayesian Inference (BI), and Machine Learning (ML). A comprehensive database was constructed from three-point bending tests on SFRC specimens, encompassing various compressive strengths, fiber quantities, and geometric parameters, to identify key factors influencing material properties.The findings indicate that all three methodologies yield comparable predictive capabilities for flexural responses in SFRC. Notably, FI models emphasize the importance of compressive strength and fiber volume fraction, along with fiber properties such as non-dimensional length and tensile strength. BI models enhance predictive stability by integrating prior knowledge and quantifying uncertainty, demonstrating their advantage, particularly in data-scarce situations. Additionally, ML analysis reveals that linear regression (LR) models can achieve accuracy similar to or greater than that of more complex models. This research provides novel insights into the application of BI and ML in concrete technology, emphasizing their potential to enhance predictive modeling. Additionally, it offers practical guidelines for optimizing SFRC design through a case study that compares residual flexural strengths obtained via Bayesian analysis, classifying the material in accordance with Annex L of the new Eurocode 2.

Consolidation characteristics of compacted clayey soils treated with various biomass ashes

The increasing volume of surplus soil generated from excavation works in infrastructure projects such as roads, railroads, and subway facilities poses significant environmental and logistical challenges, particularly in terms of its disposal. Therefore, the development of engineering technologies that promote the effective use of surplus soil has intensified. Among surplus soils, clay is soft and must be treated when used as a backfill or fill material. Cement-based stabilizers are commonly used for soil treatment; however, the production of cement involves high carbon-dioxide emissions, which conflicts with Japan's carbon-neutrality goals. This study investigates the use of alternative stabilizers derived from biomass waste, specifically palm kernel shell ash (PKSA) and rice husk ash (RHA), to treat clayey soils intended for use as a backfill material in road construction. Experiments are conducted to evaluate the compaction and consolidation properties of clayey soils treated with PKSA and RHA. The results indicate that both stabilizers reduced the maximum dry density and increased the optimum water content of the treated soils. PKSA and RHA treatments enhanced compaction control, particularly on the wet side above the optimum water content, thus facilitating the achievement of a high compaction degree of 95 % under high initial water contents. Consolidation test results indicate that treatment with PKSA and RHA increases the consolidation yielding stress and reduces the volume compressibility, and that these effects are more pronounced at higher compaction levels. These results suggest that adding PKSA or RHA can expand the load range that exhibits elastic settlement and may reduce the consolidation settlement. At the same addition rate, PKSA treatment increases the consolidation yielding stress more significantly than RHA treatment. Additionally, PKSA treatment improves the stiffness and reduces the hydraulic conductivity at lower consolidation pressures compared with RHA treatment, thus indicating the greater effect of PKSA. Based on results of scanning electron microscopy, the enhancement in the stiffness and permeability afforded by PKSA is attributed to the formation of needle-like ettringite crystals, which strengthened the soil structure. By contrast, RHA treatment results in densely packed particles, which is attributable to limited hydration reactions caused by low CaO and high SiO₂ contents. Thus, different mechanisms can result in different consolidation parameters of PKSA- and RHA-treated clays. However, both the PKSA- and RHA-treated clays indicate reduced coefficients of volume compressibility and permeability at a compaction degree of 95 %, with a stabilizer-to-clay ratio of up to 15 % by dry mass. Because neither PKSA nor RHA require high addition rates to improve the properties of surplus soft clays, these results suggest that PKSA and RHA can effectively enhance the compaction and consolidation properties of clayey soils. PKSA and RHA treatments are sustainable alternatives to the conventional cement-based treatments and support the environmental goals of construction projects.

Experimental study on stability and heat transfer characteristics of separated heat pipe with a compressible volume condenser

A novel Separated Heat Pipe (SHP) system incorporating two magnetic spheres (SHPMS) was proposed for power generation (US Patent 11365653B2, 2022) using low-grade thermal energy, or offering both reliable emergency power and efficient heat transfer for spent fuel pools. This paper reports the experimental investigation on flow and heat transfer characteristics of the SHP, providing a foundation for the R&D of SHPMS. The SHP system features a unique shell-and-tube condenser structure, where the tube side serves as the cooling coil, while the shell side functions as the condenser chamber, with the dual roles of liquid storage and surge tank. The study researched the stability and heat transfer performance of the SHP under various parameters, including filling ratios ranging from 17 % to 98 %, cooling temperatures between 14 °C and 22 °C, and system pressures from 630 to 830 kPa. Analysis of instantaneous temperature, pressure, and flow patterns reveals the absence of high-frequency oscillations or alternating flow patterns, indicating that the condenser's condensing chamber may eliminate the instability in the SHP. Comparative analysis of the heat transfer coefficient and thermal resistance indicates that higher filling ratios and system pressures impair heat transfer performance, with optimal results at lower filling ratios (17 %–55 %) and pressure (630 kPa), where the higher heat transfer coefficient and lower thermal resistance were observed. Cooling temperatures showed little impact on heat transfer, allowing it to be chosen based on safety and energy efficiency needs. This study provides a new perspective on SHP systems with compressible volume condenser, offering a potential solution to address the instability challenges of SHP and the selection of operation parameters.

Perioperative Evaluation and Monitoring of Percutaneous Balloon Compression in Treatment of Trigeminal Neuralgia

BACKGROUND AND OBJECTIVES: Multiple factors may influence the clinical outcomes of percutaneous balloon compression (PBC), including intraluminal balloon pressure, volume, and Meckel's cave volume. In this article, we aimed to investigate the clinical value of the perioperative assessment and monitoring of balloon compression in the treatment of trigeminal neuralgia (TN). METHODS: Thirty-seven patients who underwent PBC were prospectively enrolled. The patient underwent preoperative high-resolution 3.0-T MRI for the 3-dimensional reconstruction of Meckel's cave, while intraoperative recordings of intraluminal pressure and balloon volume were conducted simultaneously. Primary outcomes included postoperative numbness and pain recurrence up to 24 months after discharge. RESULTS: Sensory deficiency was primarily reported within the first month, and approximately 38% of the patients presented with symptomatic numbness in the facial region. Subgroup analysis indicated no statistically significant difference in intraluminal balloon pressure between patients with facial numbness and asymptomatic individuals. This impairment in trigeminal sensation eventually recovered at the 24-month follow-up. By contrast, the long-term recurrence rate of TN was approximately 25% (5/20 patients) 2 years postoperatively. Furthermore, we found that the intraluminal balloon pressure was significantly lower among patients with recurrent pain (102.8 ± 11.0 vs 135.7 ± 5.1 kPa, P < .05). Although no significant differences in balloon or Meckel's cave volume were observed between subgroups, we found a positive and significant correlation between the volume of Meckel's cave and balloon. CONCLUSION: Facial numbness remains a common but short-term symptom of PBC for TN. This study indicates that a higher intraluminal balloon pressure may be associated with a lower risk of recurrent trigeminal pain. Preoperative reconstruction of Meckel cave may help to predict the volume of intraoperative balloon compression. We consider it feasible and necessary to conduct a perioperative assessment of balloon compression in the treatment of TN.

Experimental study on pressure drop fluctuations for boiling flow at various gravity levels

Experiments were conducted on the pressure drop fluctuations of R245fa boiling through a horizontal microchannel with a diameter of 0.94 mm and a heated length of 170 mm at various gravity levels. The visualization results show that under inlet saturation conditions, three typical periodic oscillation modes are observed: continuous two-phase flow, bubbly/annular alternating flow, and churn/annular alternating flow. The flow oscillation characteristics within the channel are closely related to bubble dynamics, the vapor–liquid interface evolution, and the upstream compressible vapor volume. It has also been found that increasing the mass flux or decreasing the heat flux can enhance the suppression effect on pressure drop oscillation. In addition, under inlet subcooling conditions, although the total pressure drop increases with the increase in gravity level (1–2.78 g), and the amplitude of pressure drop fluctuation first increases and then decreases with the increase in gravity level, with the transition point occurring approximately at an = 1.10 g. The impact of gravity level on the amplitude of pressure drop fluctuation is primarily determined by the relative dominance of bubbly flow and annular flow within the channel.

Lossy Compression of Integer Astronomical Images Preserving Photometric Properties* *This work was supported in part by the Spanish Ministry of Science and Innovation (MICINN) and by the European Regional Development Fund (FEDER), funded by MCIN/AEI/10.13039/501100011033/FEDER, UE, under grant PID2021-125258OB-I00; also by the Catalan Government under grant SGR2021-00643; and also by the “PhotSat” project under the Institute for Space Studies of

Observatories are producing astronomical image data at quickly increasing rates. As a result, the efficiency of the compression methods employed is critical to meet the storage and distribution requirements of both observatories and scientists. This paper presents a novel lossy compression technique that is able to preserve the results of photometry analysis with high fidelity while improving upon the state of the art in terms of compression performance. The proposed compression pipeline combines a flexible bi-region quantization scheme with the lossless, dictionary-based, LPAQ9M encoder. The quantization process allows compression performance and photometric fidelity to be precisely tailored to different scientific requirements. A representative data set of 16-bit integer astronomical images produced by telescopes from all around the world has been employed to empirically assess its compression-fidelity trade-offs, and compare them to those of the de facto standard Fpack compressor. In these experiments, the widespread SExtractor software is employed as the ground truth for photometric analysis. Results indicate that after lossy compression with our proposed method, the decompressed data allows consistent detection of over 99% of all astronomical objects for all tested telescopes, maintaining the highest photometric fidelity (as compared to state of the art lossy techniques). When compared to the best configuration of Fpack (Hcompress lossy using 1 quantization parameter) at similar compression rates, our proposed method provides better photometry precision: 7.15% more objects are detected with magnitude errors below 0.01, and 9.13% more objects with magnitudes below SExtractor’s estimated measurement error. Compared to the best lossless compression results, the proposed pipeline allows us to reduce the compressed data set volume by up to 38.75% and 27.94% while maintaining 90% and 95%, respectively, of the detected objects with magnitude differences lower than 0.01 mag; and up to 18.93% while maintaining 90% of the detected objects with magnitude differences lower than the photometric measure error.

Comparison of soil improvement techniques on the development of efficient consolidation response

A comprehensive experimental program including two distinct series of consolidation tests was performed on clay specimens prepared at different dry weight proportions including 0%, 1%, 2.5%, 5%, 7.5%, 10% polypropylene fiber or lime by weight mixed with clayey soil. Fiber inclusion into clay resulted in enhancement of compressive strength characteristics, improvement of hydraulic properties that is an advantage for modification of stability and durability properties of clayey soil under loads. Similarly, the higher hydraulic conductivity of clay resulted that will shorthen duration of consolidation settlement, hence, eventually influence completion of plastic consolidation deformation favorably for soft clays. Lime-treatment on clay specimens showed that the compressibility properties are improved such that the strength of clay against loading enhances, exhibits less consolidation deformation under load owing to increase in lime content. On the other hand, clay becomes highly impermeable, displays substantially larger water-resistant properties because of increased lime mass proportion (i.e. time-extension) in clayey soil that results in prolongation of expulsion of excess porewater pressure from clay due to load application, relevant induced stresses. Fiber-inclusion resulted in exhibiting logarithmic decrement with a mild rate of decline while lime-treatment led to exponential reduction with a sharp rate of drop for compression index (Cc), compressibility coefficient (αv), volume compressibility coefficient (mv). Further, fiber-inclusion stimulated exponential and quadratical increment whereas lime-treatment induced exponential decrement for coefficient of consolidation (cv), hydraulic conductivity (k), respectively. As a result, the Cc, αv, mv enhanced on the order of within 10 at average of 80% to 90% with a minimum of 70% by value for both fiber-reinforcement and lime-stabilization soil-stabilization techniques. The cv, k improved on the order of within 10 at average of 75% to 85% by value for fiber-reinforcement whereas dis-improved on the order of within 10 at average of 70% to 80% by value for lime-stabilization.

Experimental study on seismic performance of glulam structural columns with anchored connections

In current timber structures, the low initial stiffness, and weak bending resistance of the connections result in significant structural deformation and failures. To improve the mechanical capabilities of timber structural joints, a novel timber-component anchorage system with robust bending resistance was introduced. Thirteen scaled-down specimens of glulam columns with anchored connections were meticulously fabricated for testing, scaled at a ratio of 1/2. Cyclic loading tests were conducted, considering three types of the volume compression percentage of confined wood perpendicular to the grain; and five axial-load levels. Subsequently, various seismic performance aspects of glulam columns with anchored connections were examined, including the failure mode, hysteresis behavior, envelope curve, strength degradation, stiffness degradation, energy dissipation capacity, and critical points. During the analysis, the influence of the P–Δ effect on the results was discussed and a damage-based hysteretic model was presented. Finally, a comparison of the mechanical performance for various types of timber structural joints was conducted. The findings revealed that the failure mode of the anchored glulam columns occurred as cracking perpendicular to the grain, and the anchored columns exhibited superior bending resistance and overall seismic performance.

The formation of CaCO3-based binder by carbonating high-dosage Ca(OH)2 + slag + NaHCO3 (HCHSN) cement paste

Normally, carbonation can cause the decalcification of C-(A)-S-H gel of alkali-activated cement and the degradation of mechanical properties. While, we propose another possibility to form CaCO3-based binder by carbonating the alkali-activated slag cement of high-dosage Ca(OH)2 (30 %) + slag (70 %) + NaHCO3 (5.11 % by weight of Ca(OH)2 and slag) (HCHSN) in this study. The results supported that the compressive strength and volume stability of HCHSN cement paste can be improved by the carbonation curing and the carbonated HCHSN cement paste could reach a maximum compressive strength of 32.4 MPa. According to the micro-analysis of XRD, TGA, FTIR, 1H NMR, BSE and SEM, the carbonated HCHSN cement paste was developed into a CaCO3-based binder with a CaCO3 content approaching 60 % (based on the mass of the samples heated to 800℃). NaHCO3 played a key role in the formation of the CaCO3-based binder, which not only accelerated the carbonation rate, but also promoted the carbonation of slag. The eco-efficiency assessment showed that compared to the production of 12.5 kg CO2 /MPa/t from carbonated ordinary Portland cement, the carbonated HCHSN cement paste only produced 3.5 kg CO2 /MPa/t, making it a very green CaCO3-based cementitious materials.

Surgical Resection Followed by Stereotactic Radiosurgery (S+SRS) Versus SRS Alone for Large Posterior Fossa Brain Metastases: A Comparative Analysis of Outcomes and Factors Guiding Treatment Modality Selection.

Around 20% of cancer patients will develop brain metastases (BrMs), with 15-25% occurring in the posterior fossa (PF). Although the effectiveness of systemic therapies is increasing, surgery followed by stereotactic radiosurgery (S+SRS) versus definitive SRS remains the mainstay of treatment. Given the space restrictions within the PF, patients with BrMs in this location are at higher risk of brainstem compression, hydrocephalus, herniation, coma, and death. However, the criteria for treating large PF BrMs with S+SRS versus definitive SRS remains unclear. We reviewed a prospective registry database (2009 to 2020) and identified 64 patients with large PF BrMs (≥4 cc) treated with SRS or S+SRS. Clinical and radiological parameters were analyzed. The two endpoints were overall survival (OS) and local failure (LF). Patients in the S+SRS group were more highly symptomatic than patients in the SRS group. Gait imbalance and intracranial pressure symptoms were 97% and 80%, and 47% and 35% for S+SRS and SRS, respectively. Radiologically, there were significant differences in the mean volume of the lesions [6.7 cm3 in SRS vs. 29.8 cm3 in the S+SRS cohort, (p < 0.001)]; compression of the fourth ventricle [47% in SRS vs. 96% in S+SRS cohort, (p < 0.001)]; and hydrocephalus [0% in SRS vs. 29% in S+SRS cohort, (p < 0.001)]. Patients treated with S+SRS had a higher Graded Prognostic Assessment (GPA). LF was 12 and 17 months for SRS and S+SRS, respectively. Moreover, the S+SRS group had improved OS (12 vs. 26 months, p = 0.001). A higher proportion of patients treated with S+SRS presented with hydrocephalus, fourth-ventricle compression, and larger lesion volumes. SRS-alone patients had a lower KPS, a lower GPA, and more brain metastases. S+SRS correlated with improved OS, suggesting that it should be seriously considered for patients with large PF-BrM.

Influence of cation disorder on the mineral physics of ankerite

Abstract The structural evolution and compressibility of ordered and disordered ankerite at pressures up to ~25 GPa using synchrotron single crystal X-ray diffraction in diamond anvil cell was analyzed. Ordered ankerite (space group R3) undergoes discontinuous phase transition between 12.15 and 13.45 GPa to a high-pressure structure called ankerite-II (space group P1) that has Ca in eight-fold coordination. Disordered ankerite (R3c space group) does not undergo a phase transition in the investigated pressure range. A Birch-Murnaghan equation of state has been used to fit the volume compressibility. Ordered ankerite [K0V=95(1) GPa - K’=3.8(3)] appears slightly more compressible than disordered ankerite [K0V=99(1) GPa - K’=2.7(1)]. The phase transition in ordered ankerite has a change in volume of approximately 0.6% and K13.45V=110(11) GPa - K’=7(3) for ankerite-II. The possible significance of this differential behavior of ordered and disordered ankerite is discussed.

A single-cell 3D dynamic volume control system for chondrocytes.

In articular cartilage, zone-specific cellular morphology is a typical characteristic of cartilage tissue, which is related with chondrocyte function, inflammation and osteoarthritis (OA). Chondrocyte hypertrophic phenotype is a criticle physiological process which indicates a hallmark of chondrocyte terminal differentiation and bone formation. Thus, developing a in vitro cell culture system for dynamic regulation of single chondrocyte volume at a three-dimensional (3D) level is particularly necessary for understanding how physical cues of matrix microenvironment regulate chondrocyte fate and the degeneration of articular cartilage. Here, based on the soft lithography techniques, we have constructed well-defined single-cell 3D dynamic volume control system to recapitulate the physiological matrix microenvironment of single chondrocyte niche. The results of finite element analysis indicated that the stress and strain distribution in the cell culture region is homogeneous during the stretching process. Additionally, 3D dynamic volume expansion and compression of single cells in physiological or hyperphysiological can be realized in this cell culture system. Our device for single-cell 3D dynamic culture provides a microphysiological culture system for chondrocytes to explore the mechanisms of cartilage hypertrophy, as well as develops a new paradigm for functional cartilage tissue engineering and regenerative medicine.

Crystal structure and magnetic properties of Yb2Pt2Pb under multi-extreme conditions

ABSTRACT Structural and magnetic properties of the Shastry-Sutherland material Yb2Pt2Pb were studied in single-crystalline form under pressures up to 10 GPa, magnetic fields up to 17 T, and temperatures down to 0.3 K. Surprisingly robust magnetic order is observed with the Néel temperature T N = 2.1 K stable up to 8.1 GPa. Indication of an additional magnetic phase formation can be traced in resistivity data for magnetic field along the c-axis exceeding the (pressure-dependent) metamagnetic transition. The related anomaly shifts to higher temperatures with increasing field, merging T N at the tricritical point. Experiments with μ0 H // [110] revealed the pressure stabilization of observed magnetic phases with respect to the magnetic field. The crystal-structure type is stable up to 10 GPa, without any sign of symmetry change, exhibiting moderate volume compressibility with bulk modulus B = 116(13) GPa, in good agreement with B = 118 GPa provided by the density functional theory.

Influence of compliance and resistance of the test lung on the accuracy of the tidal volume delivered by the ventilator

BackgroundLarge variations in respiratory system compliance and resistance may cause the accuracy of tidal volume (VT) delivery beyond the declared range. This study aimed at evaluating the accuracy of VT delivery using a test lung model to simulate pulmonary mechanics under normal or disease conditions.MethodsIn vitro assessment of the VT delivery accuracy was carried out on two commercial ventilators. Measurements of the inspired and expired VT from the ventilator and FlowAnalyser were compared to evaluate the separated and combined influences of compliance and resistance on the delivered VT accuracy. To do this, the errors of five delivered volumes (30 ml, 50 ml, 100 ml, 300 ml, and 500 ml) were checked under 29 test conditions involving a total of 27 combinations of resistance and compliance.ResultsFor the tested ventilator S1 with a flow sensor near the expiratory valve, the average of expired VT errors (ΔVTexp) in three measurements (4 test conditions for each measurement) correlated to test lung compliance (r=-0.96, p = 0.044), and the average of inspired VT errors (ΔVTins) correlated to compliance (r = 0.89, p = 0.106); for the tested ventilator S2 with a flow sensor located at the Y piece, no clear relationship between compliance and ΔVTexp or ΔVTins was found. Furthermore, on two ventilators tested, the current measurements revealed a poor correlation between test lung resistance and ΔVTins or ΔVTexp, and the maximum values of ΔVTexp and ΔVTins correspond to the maximum resistance of 200 cmH2O/(L/s), at which the phenomenon of the flap fluttering in the variable orifice flow senor was observed, and the recorded peak inspiratory pressure (Ppeak) was much higher than the Ppeak estimated by the classical equation of motion. In contrast, at the lower resistance values of 5, 20, 50 and 100 cmH2O/(L/s), the recorded Ppeak was very close to the estimated Ppeak. Overall, the delivered VT errors were in the range of ± 14% on two ventilators studied.ConclusionsDepending on the placement site of the flow sensor in the ventilator circuit, the compliance and resistance of the test lung have different influences on the accuracy of VT delivery, which is further attributed to different fluid dynamics effects of the compliance and resistance. The main influence of compliance is to raise the peak inspiratory pressure Ppeak, thereby increasing the compression volume within the ventilator circuit; whereas a high resistance not only contributes to elevating Ppeak, but more importantly, it governs the gas flow conditions. Ppeak is a critical predictive indicator for the accuracy of the VT delivered by a ventilator.

Assessing the validity and limits of linear density models for predicting dissociation–association equilibria in supercritical water

A linear relationship between the logarithms of solute dissociation constants, log(K), and the density of water, log (ρH2O), has empirically been demonstrated for decades and raised hope for an universal formalism to describe solute thermodynamic properties over wide ranges of temperature and density at supercritical conditions. Yet, neither a theoretical foundation nor an assessment of the ranges of validity have been presented. Here, we use classical molecular dynamics (MD) simulations as a complementary tool to assess the validity of this linear relationship for the example of NaCl and reveal its limits at water densities below ca. 0.3gcm−3. The derivative ∂log(K)/∂log(ρH2O) is calculated based on the volume of reaction and water compressibility derived from the simulations performed in the isothermal–isobaric ensemble at 673K. Our results corroborate the linear dependence of log(K) vs. log(ρH2O) in the experimentally studied density range and suggest that the linear dependence also extends to higher densities. However, towards lower densities, log(K) decreases and takes on values that are lower than would be expected by simply extrapolating the linear behavior. This decrease is consistent with earlier theoretical predictions for the behavior of log(K) at vapor-like densities but questions the relevance of some indirect experimental evidence obtained at low temperatures. Although the function described by log(K) vs log(ρH2O) is non-linear in the low density range, it can be considered well-behaved even at near critical conditions.

Buoyancy regulation in insects.

Multiple insect lineages have successfully reinvaded the aquatic environment, evolving to complete either part or all of their life cycle submerged in water. While these insects vary in their reliance on atmospheric oxygen, with many having the ability to extract dissolved oxygen directly from the water, all retain an internal air-filled respiratory system, their tracheal system, due to their terrestrial origins. However, carrying air within their tracheal system, and even augmenting this volume with additional air bubbles carried on their body, dramatically increases their buoyancy which can make it challenging to remain submerged. But by manipulating this air volume a few aquatic insects can deliberately alter or regulate their position in the water column. Unlike cephalopods and teleost fish that control the volume of gas within their hydrostatic organs by either using osmosis to pull liquid from a rigid chamber or secreting oxygen at high pressure to inflate a flexible chamber, insects have evolved hydrostatic control mechanisms that rely either on the temporary stabilization of a compressible air-bubble volume using O2 unloaded from hemoglobin, or the mechanical expansion and contraction of a gas-filled volume with rigid, gas-permeable walls. The ability to increase their buoyancy while submerged separates aquatic insects from the buoyancy compensation achieved by other air-breathing aquatic animals which also use air within their respiratory systems to offset their submerged weight. The mechanisms they have evolved to achieve this are unique and provide new insights into the function and evolution of mechanochemical systems.

Cloud-Edge Collaborative Optimization Based on Distributed UAV Network

With the continuous development of mobile communication technology, edge intelligence has received widespread attention from academia. However, when enabling edge intelligence in Unmanned Aerial Vehicle (UAV) networks where drones serve as edge devices, the problem of insufficient computing power often arises due to limited storage and computing resources. In order to solve the problem of insufficient UAV computing power, this paper proposes a distributed cloud-edge collaborative optimization algorithm (DCECOA). The core idea of the DCECOA is to make full use of the local data of edge devices (i.e., UAVs) to optimize the neural network model more efficiently and achieve model volume compression. Compared with the traditional Taylor evaluation criterion, this algorithm consumes less resources on the communication uplink. The neural network model compressed by the proposed optimization algorithm can achieve higher performance under the same compression rate.

Physical properties of tween 20 + di-potassium hydrogen phosphate anhydrous (or tri-potassium phosphate 1,5-hydrate) + water from 288.15 K to 318.15 K

ABSTRACT The present study investigates the characterisation of binary and ternary mixtures involving a surfactant such as Tween 20 and various potassium salts in aqueous solutions. The ternary mixtures can form two distinct immiscible liquid phases. Several physical properties, including refractive index, density, and speed of sound, were measured, and derived properties such as excess molar volume and isentropic compressibility were calculated. The research focuses on the behaviour of aqueous binary and ternary mixtures composed of Tween 20, salts (di-potassium hydrogen phosphate anhydrous and tri-potassium phosphate 1,5-hydrate), and water in their homogeneous phases. It examines the influence of the surfactant and salts and the effect of temperature on these physical properties for homogeneous mixtures. Additionally, the physical properties of the equilibrium phases were determined to cover all the homogeneous zones comprehensively.

Unraveling Superior Elasticity and Controlled Thermal Expansion in Trigonal MBO3 (M=Al, Ga) with Isolated [BO3] Group: A Theoretical Perspective

AbstractA comprehensive theoretical investigation employing density functional theory explores the electronic structure, temperature‐dependent elasticity, thermodynamic properties, and chemical bonding of trigonal MBO3 (M=Al, Ga) with isolated [BO3] groups. The results uncover MBO3 (M=Al, Ga) as indirect semiconductors with superior mechanical stability, characterized by greater resistance to volume compression over shear deformation. Their elasticity exhibits relatively weak temperature dependence, suggesting excellent thermal stability. Thermodynamic analysis predicts that GaBO3 has a higher thermal expansion coefficient than AlBO3, approximately 2.1×10−5 K−1 and 1.8×10−5 K−1 at 300 K, respectively. Significantly, the overall thermal expansion coefficients of GaBO3 and AlBO3 are lower compared to other borate materials containing isolated [BO3] groups. Chemical bonding insights reveal that GaBO3′s larger thermal expansion is attributed to its larger atomic displacement parameters and weaker Ga−O bond strength. This research positions MBO3 (M=Al, Ga) as prime candidates for optical device applications due to their well‐characterized elasticity and controlled thermal expansion.