Upward Direction Research Articles

DFT based analysis of pressure driven mechanical, opto-electronic, and thermoelectric properties in lead-free InGeX3 (X = Cl, Br) perovskites for solar energy applications

Lead halide perovskites have distinct physiochemical properties and demonstrate remarkable power conversion efficiency. We used density functional theory to investigate the electrical, optical, structural, and elastic features of non-toxic InGeCl3 and InGeBr3 halide perovskite compounds at different hydrostatic pressures, from 0 to 8 GPa. InGeCl3 and InGeBr3 halide perovskite exhibit noteworthy changes in their electronic and optical properties under different pressure conditions. When the pressure is 0 GPa, the direct bandgap for InGeCl3 is 0.886 eV, and for InGeBr3 it is 0.536 eV. This gap decreases as the pressure rises. Specifically, InGeBr3 exhibits conducting properties at 3 GPa due to its larger bromine atoms, whereas InGeCl3 requires a higher pressure of 6 GPa to achieve similar conductivity. This type of nature suggests that larger halogen atoms reduce the bandgap more effectively under pressure. As the pressure increases, the behavior of the lattice constant and unit cell volume decreases constantly, from 5.257 and 145.267 Å3 for InGeCl3 to 5.509 and 167.168 Å3 for InGeBr3 at 0 GPa for both compounds. When subjected to pressure, the bonds between In-X and Ge-X atoms experience compression, leading to a decrease in surface area and an enhancement in mechanical strength. Overall, the compounds exhibit characteristics of semiconductors, as evidenced by evaluations of their electrical properties. As pressure increases, the bandgap decreases linearly, narrowing until it aligns with the Fermi level, leading to a transition toward a metallic state. In addition, the pressure induces a rise in the electrical density of states around the Fermi level by displacing valence band electrons in an upward direction. As pressure increases, the electron density peak shifts to lower photon energy values. Notably, InGeCl3 exhibits a more pronounced shift in this peak compared to InGeBr3, indicating greater sensitivity to pressure. In terms of optical properties, both compounds demonstrate significant absorption coefficients in the visible region, suggesting their potential suitability for photovoltaic applications. The dielectric constant, absorption, and reflectivity values all increase gradually as pressure increases. The absorption spectra shift toward longer wavelengths. Furthermore, the mechanical properties analysis reveals that all InGeX3 compounds are mechanically stable up to 8 GPa pressure.

Зміни у показниках периферійного зору баскетболісток 11–12 років під впливом спеціально підібраних вправ

In team game sports, peripheral vision can be useful for simultaneously tracking the movements of opponents and teammates. The purpose of the study: to experimentally test the effectiveness of specially selected exercises aimed at changes in the peripheral vision of basketball players aged 11-12 years. Research methods: theoretical analysis of scientific and methodological literature, pyrometry method, pedagogical experiment, methods of mathematical statistics. The device ‘Forster's Perimeter’ was used to determine the index of peripheral visual field. The field of vision was determined for the left and right eyes separately for the white and green colours of the two main meridians - horizontal outward (to the temple) and to the middle (to the nose) and vertical - upward and downward. The study was conducted at the research laboratory of the Kharkiv State Academy of Physical Culture. The study involved 30 female basketball players from Kharkiv aged 11-12 years. In order to establish the effectiveness of using specially selected exercises during training, young basketball players were divided into control and experimental groups, each of which consisted of 15 girls. For 4 months, the training process of the experimental group was based on the standard training programme for basketball for children and youth sports schools and was supplemented by specially selected sets of exercises aimed at developing peripheral vision and improving the condition of the eye muscles. Special sets of exercises aimed at developing peripheral vision. Results of the study. The ‘Forster Perimeter’ device does not allow to set the field of vision in the selected direction by more than 90º. It should be noted that the index of peripheral vision horizontally outward, both with the right and left eyes, for both colours in all basketball players exceeded this index. Thus, it was not possible to establish the indicators of peripheral vision in the horizontal outward direction and to study the influence of specially selected exercises on these indicators. The analysis of indicators in the direction up, down and inwards revealed the highest indicators along the vertical meridian with the right and left eyes downwards, both in the CG and EG. Comparing the indicators of peripheral vision of the right and left eyes to white, it was found that in the EG there were significant differences in the indicators upwards (t=2.54, p<0.05) and in the middle (t=4.47, p<0.05), in the CG - in all three directions (t=2.43, p<0.05; t=2.27, p<0.05, t=3.56, p<0.05. In indicators of peripheral vision of the right and left eyes for green colour significant differences are observed only in EG in the upward direction (t=2.19; p<0.05) After the pedagogical experiment the repeated testing was conducted, the results of which indicated a significant improvement of indicators of peripheral vision of basketball players of EC of the right eye both for white and green colour in all three directions (p<0.005). Significant changes in the indicators of peripheral vision of the left eye occurred only for white colour along the vertical meridian downwards (t=2.06; p<0.05) and upwards (t=2.04; p<0.05). For other indicators, the changes were positive, but not significant. Conclusions. The use of specially selected exercises positively influenced on indicators of peripheral vision of sportswomen of 11-12 years old of EG. Thus, the improvement in the right eye was 5.08% upwards, 6.08% downwards, 9.58% in the middle of white colour; in green colour - 11.82%, 5.86%, 5.91%, respectively. In the left eye, the improvement was 6.58% for white, 7.57% for blue, and 1.08% for green; 7.38%, 7.81%, 5.70% for green, respectively.

Model Komunikasi Organisasi Pemberdayaan Kesejahteraan Keluarga (PKK) Dalam Mengimplementasikan Program Bank Sampah Duren

The organizational communication model functions as a tool to ensure that communication is on target in accordance with the objectives of the PKK RT 08 Kampung Padurenan organization, namely to advance the environment by facilitating the community in managing waste banks. This study aims to determine the Organizational Communication Model (PKK) in Implementing the Duren Waste Bank Program. The organizational communication model in this study uses the Stimulus-Response model and the Aristotle model with upward, downward and sideways communication directions. Flor's environmental communication theory is used to complement the organizational communication model. The research method used is descriptive qualitative. Data collection techniques include interviews, observations, documentation and literature studies. The results of this study indicate that the organizational communication model carried out by the PKK RT 08 organization in implementing the Duren Waste Bank was declared successful. This can be seen from a clear understanding of communication so that it can be ensured that all organizations involved understand what is being said. This Organizational Communication Process can also be declared unsuccessful due to the lack of active participation in communication from the head of the waste bank in each of his work program activities, so that members often feel that leaders can only give orders without giving examples.

Field‐effect modulated water‐splitting by photoinduced charge carriers on BiFeO3 film

AbstractIn this study, the field‐effect generated by illuminated p‐type ferroelectric bismuth ferrite (BiFeO3 or BFO) semiconductor film is utilized to modulate the water‐splitting performance of a system with a macroscopic spatial separation between the anode and cathode. When the BFO film in contact with an electrolyte is illuminated with a light of sufficiently high frequency, an electrolytic conducting channel is formed due to the field effect induced by photoexcited charge carriers in the BFO film, which in turn alters the water‐splitting pathway and the reaction mechanism. The field effect can be modulated by changing the orientation of the ferroelectric polarization in the BFO film. With a BFO film of 4.5 mm channel length and an overall upward ferroelectric polarization direction, a ∼30% increase in water‐splitting performance in a neutral‐pH electrolyte is achieved in the presence of field‐effect induced by a 20 mW 405 nm light source. The mechanism behind the field‐effect modulation is also further verified by monitoring the pH of the electrolyte during the water‐splitting process and conducting thresholding analysis on the recorded data. The field‐effect modulation described in this study can potentially be used to enhance the performance of a photoelectrochemical water‐splitting system by taking advantage of the presence of light illumination in the system or be utilized in electrochemical sensing applications.

EDT demonstration for keeping low altitude orbit using carbon nanotube tether

This paper describes an electrodynamic tether system (EDT). Conductive tethers are used to overcome atmospheric resistance in low orbit and extend orbit life using EDT propulsion. First, based on the conceptual design, the feasibility of the EDT system has been evaluated through simulation. Especially, the induced electromotive force of the conductive tether has been clarified, the amount of current required to keep the orbital altitude, and the requirements for each device. Then, feasibilities of the key mission devices have been evaluated experimentally. Those are the conductive tether, the electron emission device, and the tether extension control mechanism. The conductive tether is planned to be made of carbon nanotubes, which are attracting attention as a new material, and its properties are evaluated. The electron-emitting device has been evaluated as a device that can be mounted on a micro/nano satellite. Tether extension mechanism was developed in our past project, then it should be evaluated with the purpose of adapting to conductive tether systems. Based on the evaluation, the orbital demonstration mission plan using a micro/nano satellite has been introduced. The mission is as follows. The conductive tether is extended and stabilized by the gravity gradient. By emitting electrons from an electron emitter mounted on a high-altitude satellite and collecting electrons on bare tether at low-altitude end, a current is generated from the high-altitude side to the low-altitude side. According to Fleming's law, the Lorentz force is generated in the direction of the orbiting accelerated, so it can be propelled in the upward direction of the orbit.

Aerodynamic characteristics of wind turbines considering the inhomogeneity and periodic incentive of wake effects

In wind farms, the wake can lead to a loss of output power, and the uneven characteristics of wake can also exacerbate the fatigue load of downstream wind turbine (WT), affecting their operating life. To explore the impact of wake effects on downstream WT, this article proposes a new method for calculating the load of WT wake wind conditions and verifies it. Establishing a 3DJG wake model coupled with improved BEM for wind turbine aerodynamic performance calculation method. The influence of downstream WT operation phase angle and positions of 3D wake on the time-varying aerodynamic characteristics of downstream WTs was discussed from three perspectives: Blade elements on the spanwise, single blade and wind rotor. Results shown that: (1) For the blade element, calculated the shear force in the flapwise direction and the edgewise direction on each blade segment. The overall shear force of blade element in the vertical upward direction of WT blades is significantly greater than that in other directions. The non-uniformity of the wake is not sufficient to change the position of the maximum shear force on the blade. The position of the maximum shear force at each wake position is in the rear segments of the blade; (2) For the single blade, the most severe load fluctuation occurs when it is in the partial wake condition. The period of this fluctuation is 360°. When in full wake condition, the load fluctuation is relatively small, and due to the symmetry of the wake, the load fluctuation period is only 180°. The load standard deviation (SD) of the partial wake condition increases by 51 % compared to the full wake condition. (3) For the wind rotor, different wake positions have a weighty impact on the power loss of the WT rotor. Compared to the incoming shear wind, the power loss at the wake center can reach up to 54.22 %. At the wake boundary, the power loss of the WT is only 5.6 %. The non-uniformity of wake also has a periodic impact on the power output of the entire WT rotor, with the fluctuation period is 120°, and the fluctuation amplitude of no more than 2 %. This article provides a more intuitive quantitative analysis of the impact of wake on the time-varying aerodynamic characteristics of downstream WTs. It has certain reference value for the design strength verification of WTs, as well as the yaw strategy and layout design of wind farms.

Individual differences and counterfactual thinking

ABSTRACT The study explored the impact of reasoning capabilities and five personality dimensions, measured by the 16PF-5 (extraversion, anxiety, self-control, tough-mindedness, independence), on counterfactuals and responsibility attribution in judicial cases. The authors hypothesised that individual differences in these personality traits predicted the direction, magnitude, and content of counterfactuals and responsibility judgments. The main results showed that Anxiety (positively) and Self-Control (negatively) predicted downward counterfactual judgments in a medical malpractice case, whereas people with high reasoning capabilities generated upward counterfactual in an assault case. Perfectionism positively predicted an upward direction independently of the scenarios. Extraversion and reasoning capabilities predicted the attribution of responsibility to the victim, whereas Anxiety and Tough-Mindedness predicted responsibility to external causes in the medical malpractice case. For the assault case, Self-Control predicted both the attribution of responsibility to the agent and to external causes. Results were discussed considering implications of counterfactuals in the judicial field.

Predicted community consequences of spatially explicit global change-induced processes on plant-insect networks.

Plant-insect trophic systems should be particularly sensitive to processes altering species spatial co-occurrences, as impacts on one level can cascade effectively through the strong trophic reliance to the other level. Here, we predicted the biogeography of Lepidoptera-plant communities under global-change scenarios, exploiting spatially resolved data on 423 Lepidoptera species and their 848 food plants across the German state of Baden-Württemberg (ca. 36,000 km2). We performed simulations of plant extinction and Lepidoptera expansion, and respectively assessed their cascading consequences-namely secondary extinction of Lepidoptera and change in functional distance of plants-on the interaction networks. Importantly, the simulations were spatially explicit, as we accounted for realistic landscape contexts of both processes: Plant extinctions were simulated as "regional" (a species goes extinct in the whole region at once) vs. "isolation-driven" (a species gradually goes extinct from the peripheral or isolated localities according to its real regional distribution); Lepidoptera expansions were simulated with random, northward, and upward directions according to real topography. The consequences were assessed based on empirical community composition and trophic relationships. When evaluated by regional richness, the robustness of Lepidoptera assemblages against secondary extinctions was higher under isolation-driven plant extinctions than regional plant extinction; however, this relationship was reversed when evaluated by averaged local richness. Also, with isolation-driven plant extinctions, Lepidoptera at the central sub-region of Baden-Württemberg appeared to be especially vulnerable. With Lepidoptera expansions, plants' functional distances in local communities dropped, indicating a possible increase of competition among plants, yet to a lesser extent particularly with upward movements. Together, our results suggested that the communities' composition context at the landscape scale (i.e., how communities, with respective species composition, are arranged within the landscape) matters when assessing global-change influences on interaction systems; spatially explicit consideration of such context can reveal localised consequences that are not necessarily captured via a spatially implicit, regional perspective.

Impact of double diffusion on solid particle dispersion in rotated cylinders with nano-enhanced phase change materials

This study introduces an innovative approach that combines the Incompressible Smoothed Particle Hydrodynamics method with Artificial Neural Networks to examine the dispersion of solid particles within rotated circular cylinders filled with nano-enhanced phase change materials. This method addresses the limitations of traditional numerical techniques by improving accuracy in complex geometries and dynamic boundary conditions. The various parameters are examined, including the lengths of low sources in boundary walls Lb, dimensionless time τ, Hartmann number (Ha), Darcy number (Da), thermal radiation parameter (Rd), and Rayleigh number (Ra). The solid particles are initially situated at the center gate between the two circular cylinders, maintained at elevated temperature Th and concentration Ch. Due to the upward direction of convection flow, the solid particles are consistently dispersed into the top circular cylinder. The findings offer valuable insights into the system's behavior. The dispersion of solid particles within the NEPCM is influenced by both τ and Lb, showcasing minimal dispersion for τ≤0.1 and intensified dispersion for τ≥0.2, particularly augmented by larger Lb. The heat capacity ratio (Cr) exhibits a decrease with increasing Lb at multiple time points. A decrease in the Darcy number significantly slows down the dispersion of solid particles because of the substantial resistance posed by the porous medium. As the Rayleigh number increases, there is an enhanced dispersion of solid particles into the upper circular cylinder and heightened temperature distributions. Additionally, the average Nusselt number Nu¯ and Sherwood number Sh¯ decrease with the increase in Lb due to the expansion of low-temperature and concentration source. When the length Lb was increased from 0.25 to 1, Nu¯ and Sh¯ decreased by approximately 76% and 67%, respectively, underscoring the impact of geometric configuration on heat and mass transfer efficiency. The study highlights the effectiveness of the MLP model in predicting Nu¯ and Sh¯ values through graphical analysis, showing significant agreement with the target values. The results demonstrated notable improvements in managing particle dispersion and heat/mass transfer, emphasizing the potential of this integrated approach for applications in thermal management and energy optimization.

Nonvolatile control of valley related properties and valley-contrasting transport in multiferroic van der Waals heterostructures

It is highly desirable to tune valley-related property through reversible and electrically nonvolatile methods. Taking the VSiGeP4/Al2S3 heterostructure as an example, we demonstrate that the valley splitting and valley-contrasting transport in VSiGeP4 monolayer are significantly enhanced by using a ferroelectric Al2S3 substrate. The vertical strain and electric field can modulate valley splitting, magnetic anisotropy, and magnetic ground state. The valley splitting is mainly governed by charge transfer between the two sublayers. The valley splitting and valley-contrasting transport are highly tunable when the ferroelectric polarization state of the Al2S3 substrate is the upward direction. In contrast, the valley splitting is rather robust when the ferroelectric polarization state is switched to the opposite direction. Furthermore, we propose to use electrical conversion between two opposite ferroelectric polarization states to obtain nonvolatile control of valley-related properties. Our research provides a proof-of-concept scheme to achieve electrical control based on multiferroic van der Waals heterostructures.

A rigid and compact piezoelectric motor with high output efficiency.

We introduce a novel piezoelectric stepper motor featuring high compactness, rigidity, and any direction operability. Here, not only is the structure of high novelty but also the working principle very simple. The piezo stacks unit is sandwiched between two spring finger pieces, with almost equal clamping forces applied between the top of the piezo stacks' unit and the spring finger piece. Applying individual driving signals to each of the five piezo stack pairs, causing deformation one by one in the same direction, followed by simultaneous recovery in the reverse direction, enables movement of the frame part. The optimized clamping force of the piezoelectric stack units and spring fingers ensures maximum output force. The motor's operational capability at low threshold voltages, specifically 8V for downward movement and 10V for upward movement, confirmed its efficacy in both vertical and horizontal directions. The motor's operational capability at a low threshold voltage of 10V confirmed its efficacy in both vertical and horizontal directions. At room temperature, step size ranges from 0.3 to 7.4 µm at 20Hz frequency and varying driving voltage from 10 to 180V. It has a maximum travel range of about 5mm and can lift a maximum load of 220g in an upward direction, so the maximum output force generated by this motor is 2.2 N. The compact and rigid design is capable of building an atomically resolved scanning probe microscope, and its working ability has the potential to use the cleavage of different types of samples in limited space environments, such as the small-bore superconducting magnet and low temperature.

Numerical modelling of upheaval buckling of offshore pipelines with unstressed and stressed initial imperfections

Buried offshore pipelines transporting hydrocarbon at high temperatures and pressures might experience upheaval buckling. Although pipelines are designed to remain in place, field evidence shows that the buried pipeline might displace a significantly large distance in the upward direction. In the present study, the pre- and post-buckling behaviour of offshore pipelines buried in sand is investigated considering the degradation of uplift soil resistance with the upward displacement of the pipe. The soil resistance degradation models are implemented in a finite element program, and the analyses are performed for large upward displacements even when a buckled section moves above the seabed. The simulation results show that the capacity of the pipeline to carry the load generated from an increase in pressure and temperature reduces significantly if post-peak degradation of uplift soil resistance is considered. The effects of the internal pressure modelling approach, uplift soil resistance degradation model, burial depth and pipe dimensions (diameter and thickness) on upheaval buckling for varying initial imperfections are investigated. Based on a simplified model for developing initial stresses in a pipeline during installation, it has been shown that initial stresses primarily affect the upheaval buckling at lower ranges of upward displacement of the pipe.

Influence of Double-Ducted Serpentine Nozzle Configurations on the Interaction Characteristics between the External and Nozzle Flow of Aircraft

To clarify the influence of the serpentine nozzle configurations on the flow characteristics and aerodynamic performance of aircraft, the flow features and aerodynamic performances of the double-ducted serpentine nozzles with different aspect ratios (AR), length–diameter ratios (LDR) and shielding ratios (SR) are numerically investigated. The results show that the asymmetric nozzle flow occurs due to the curved profile of serpentine nozzles, and a local accelerating effect exists at the S-bend, causing the increase in wall shear stress. The unilateral unsymmetrical expansion of the tail jet in the upward direction interacts with the separated external flow of the afterbody, forming an obvious cross-shock wave and shear layer structure. The surface pressure of the afterbody increases along the external flow direction, and decreases sharply in the separation point of the boundary layer. With the increase in AR and LDR, the local accelerating effect of the nozzle flow weakens, while with the increase in SR, the accelerating effect increases. The total pressure recovery coefficient, flow coefficient and axial thrust coefficient all decrease with the increase in AR, LDR, and SR. The thrust vector angle decreases with the increase in AR but is less affected by LDR and SR.

Ultrasound rejuvenation for upper facial skin: A randomized blinded prospective study.

Growing demand for facial rejuvenation drives advancements in these therapies, including laser, radiofrequency, and focused ultrasound, alongside thermal stimulation adjuncts. These methods, known for stimulating collagen regeneration, skin tightening, and lifting, have gained popularity due to their minimal side effects, low trauma, and high safety, demonstrating favorable outcomes in clinical practice. We sought to assess the efficacy of ultrasound skin tightening for brow lift within the scope of a procedure addressing facial sagging across the entire face. Our aim was to explore a noninvasive method capable of effectively enhancing mild to moderate brow ptosis by tightening and lifting the skin in the upper facial region. This was a rater-blinded, prospective cohort study. The upper facial region of the participants was treated with the new device, micro-focused ultrasound (MFU), in model D3.0/D2.0/M3.0. Outcomes of brow lift were measured in comparison of pretreatment and posttreatment photographs and three-dimensional (3D) vector analysis. A total of 42 participants (37 females) were enrolled, with 2 participants withdrawing from the trial, resulting in 40 subjects who completed 180-day-follow-up and evaluation. 35 (87.5%) were deemed to have clinically significant brow elevation by two blinded assessors (experienced clinicians) at 180-day posttreatment (p < 0.01). The mean change in brow height after 90-day was 2.16 ± 0.63 mm at the frontal position (straight-ahead gaze) (p < 0.01). The 3D vector analysis reveals varying magnitudes of vector displacement in the upward and outward directions of the skin on the frontal region above the eyebrows. Focused ultrasound appears to be a safe and effective method for upper facial skin rejuvenation. A single focused ultrasound treatment on the forehead and temple areas resulted in an average brow elevation of 2.1 mm.

Effects Of Wing Elasticity On Tip Vortex: 3D Deformation And 2D3C Flow Field Measurements

As aircraft embrace broader applications, the flexible wing presents a promising avenue to enhance aircraft performance across a wide range of flight conditions. Although the aerodynamic benefits of wing deformation are widely recognized, the present understanding of the tip vortex is relatively limited. This work experimentally examines the effects of wing deformation on the tip vortex of a simplified aircraft model with two kinds of elastic wings and a rigid wing. The 3D deformations and 2D3C flow fields are measured using a synchronous measurement system, which includes the high accuracy deformation measurement (HADM) method and the stereoscopic particle image velocimetry (SPIV). It is shown that increased wing elasticity leads to greater bending, with the wing tip moving along the streamwise, vertically upward, and spanwise inward directions. These deformations are closely linked to aerodynamic forces and influence the tip vortex positions. The more elastic wing, EW2, exhibits the highest vortex core position, more than 0.5 times the length of the wing root, while the other one, EW1, shows the strongest vortex in the lift-increased regime. In the early wakes, the tip vortex of the elastic wing is elongated along the spanwise direction, resulting in an asymmetric shape. As it convects downstream, the vortex core disperses via viscous diffusion, resulting in a relatively more circular shape with decreased vorticity.

Innovative landslide disaster monitoring: unmanned aerial vehicle-deployed GNSS technology

Real-time monitoring technologies of surface deformation represented by the global navigation satellite system (GNSS) are essential for landslides early warning. Monitoring methods such as GNSS require on-site manual installation. Therefore, it becomes nearly impossible to deploy surface monitoring equipment when landslides are located in high mountain valleys that are challenging for personnel to access, and/or in hazardous situations. We propose an intelligent real-time monitoring and early-warning technology that employs an unmanned aerial vehicle (UAV) as a carrier to deploy GNSS equipment. A system was initially designed with five components: an adaptive sampling GNSS receiver, an intelligent cooperative network transmission module, UAV-dropped GNSS equipment, special delivery UAV, and an intelligent monitoring and early warning cloud platform. This new technology was applied to a real landslide in Gansu Province, China, in 2020. The mean absolute error of 30 days in the east, north, and upward directions were 1.2, 1.3, and 2.9 mm/d, respectively, comparing the deformation velocity between the traditional monitoring station and the UAV-dropped monitoring station. This observation facilitated the successful prediction of a landslide hazard on 27 January 2021, allowing for a timely alert to be issued. Collectively, the results of this study established that UAV-deployed GNSS technology can accomplish unmanned deployment of GNSS equipment for landslide monitoring to ensure early warning issuance in inaccessible and/or high-risk areas.

Bottom-up butterfly model with thorax-pitch control and wing-pitch flexibility

The diversity in butterfly morphology has attracted many people around the world since ancient times. Despite morphological diversity, the wing and body kinematics of butterflies have several common features. In the present study, we constructed a bottom-up butterfly model, whose morphology and kinematics are simplified while preserving the important features of butterflies. The present bottom-up butterfly model is composed of two trapezoidal wings and a rod-shaped body with a thorax and abdomen. Its wings are flapped downward in the downstroke and backward in the upstroke by changing the geometric angle of attack (AOA). The geometric AOA is determined by the thorax-pitch and wing-pitch angles. The thorax-pitch angle is actively controlled by abdominal undulation, and the wing-pitch angle is passively determined because of a rotary spring representing the basalar and subalar muscles connecting the wings and thorax. We investigated the effectiveness of abdominal undulation for thorax-pitch control and how wing-pitch flexibility affects aerodynamic-force generation and thorax-pitch control, through numerical simulations using the immersed boundary–lattice Boltzmann method. As a result, the thorax-pitch angle perfectly follows the desired angle through abdominal undulation. In addition, there is an optimal wing-pitch flexibility that maximizes the flying speed in both the forward and upward directions, but the effect of wing-pitch flexibility on thorax-pitch control is not significant. Finally, we compared the flight behavior of the present bottom-up butterfly model with that of an actual butterfly. It was found that the present model does not reproduce reasonable body kinematics but can provide reasonable aerodynamics in butterfly flights.

Characterizations on a GRAS Electrospun Lipid-Polymer Composite Loaded with Tetrahydrocurcumin.

Electrospun/sprayed fiber films and nanoparticles were broadly studied as encapsulation techniques for bioactive compounds. Nevertheless, many of them involved using non-volatile toxic solvents or non-biodegradable polymers that were not suitable for oral consumption, thus rather limiting their application. In this research, a novel electrospun lipid-polymer composite (ELPC) was fabricated with whole generally recognized as safe (GRAS) materials including gelatin, medium chain triglyceride (MCT) and lecithin. A water-insoluble bioactive compound, tetrahydrocurcumin (TC), was encapsulated in the ELPC to enhance its delivery. Confocal laser scanning microscopy (CLSM) was utilized to examine the morphology of this ELPC and found that it was in a status between electrospun fibers and electrosprayed particles. It was able to form self-assembled emulsions (droplets visualized by CLSM) to deliver active compounds. In addition, this gelatin-based ELPC self-assembled emulsion was able to form a special emulsion gel. CLSM observation of this gel displayed that the lipophilic contents of the ELPC were encapsulated within the cluster of the hydrophilic gelatin gel network. The FTIR spectrum of the TC-loaded ELPC did not show the fingerprint pattern of crystalline TC, while it displayed the aliphatic hydrocarbon stretches from MCT and lecithin. The dissolution experiment demonstrated a relatively linear release profile of TC from the ELPC. The lipid digestion assay displayed a rapid digestion of triglycerides in the first 3-6 min, with a high extent of lipolysis. A Caco-2 intestinal monolayer transport study was performed. The ELPC delivered more TC in the upward direction than downwards. MTT study results did not report cytotoxicity for both pure TC and the ELPC-encapsulated TC under 15 μg/mL. Caco-2 cellular uptake was visualized by CLSM and semi-quantified to estimate the accumulation rate of TC in the cells over time.

Pressure fluctuation analysis for identifying the CHF approaching condition during subcooled flow boiling through a mini-channel

This study presents a new method for predicting the Critical Heat Flux (CHF) approaching condition in subcooled flow boiling based on pressure fluctuation analysis. Through experimental investigations, water flow in an upward direction was conducted within a mini-channel with one side heated to analyze the sequential boiling phenomena, including ONB (Onset of Nucleate Boiling), OFI (Onset of Flow Instability), and CHF. While ONB was determined using the slope of the wall temperature–heat flux, OFI was determined by considering the pressure drop through the channel and outlet pressure fluctuation. By analyzing the inlet pressure fluctuations, a new condition called “the CHF approaching condition” was introduced, which serves as a CHF precursor. The CHF approaching condition was found to be approximately 90% of the CHF value across all experimental scenarios. The proposed method provides an effective tool for predicting and preventing CHF, thereby reducing the potential risk of damage to the heating surface.

Upward soil arching effect under unloading: mechanism, theory and engineering application

Upward soil arching effect under unloading indicates the unloading part moves in a vertically downward direction, generating the arching zone and the loosened zone towards an upward direction. This study presents a summary of definitions, characteristics, theoretical models and engineering applications for the upward soil arching effect under unloading. The evolution of the upward soil arching effect is highly related to the unloading/differential displacement. The characteristics of the upward soil arching effect under unloading are comprehensively interpreted in terms of the normalized height of arching, the minimum soil arching ratio (at which state the maximum arching is developed) and the normalized unloading displacement to reach the maximum arching state. Two deformation-dependent theoretical models are introduced, to appropriately interpret and predict the variation of the soil arching ratio with the normalized unloading displacement (i.e., the ground reaction curve). Using the research findings for the upward soil arching effect under unloading, the settlement of the geosynthetic-reinforced pile-supported embankment as well as the face stability and ground settlement during tunnelling are proven to be precisely predicted and well controlled.