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Reactive dyes constitute a significant portion of colorants used in industries ranging from the textile industry to the paper industry. In most cases, the effluent streams from textile plants are highly colored, and treatment methods for dye decolorization such as chemical oxidation need to be explored. The oxidation processes investigated in this study are those of ozonation, ultrasound, and ultrasound-enhanced ozonation. The oxidation of an anthraquinone dye was studied under conditions of varying ultrasonic power, dye concentration, ozone concentration, pH, and temperature. Laboratory experiments were performed using a semibatch reactor by ozonating dye samples with and without ultrasound. Under conditions of constant ultrasonic radiation and continuous gas application, decolorization rates have been enhanced by ultrasound. The apparent first-order rate constants increased between 35 and 204% for the ultrasonic power inputs between 40 W/L and 120 W/L compared with ozonation alone. The effects of ultrasonic power input on the gas-liquid mass-transfer coefficient were also investigated and the results indicate that an increase in ultrasonic power input increases the mass-transfer coefficient. The mass-transfer coefficient increased between 89 and 93% for ozone inlet concentrations between 5.4 and 9.4 mg/L at an ultrasonic power of 120 W/L compared with ozonation alone. The reactions of the dye with ultrasound-enhanced ozone occurred through the hydroxyl radical pathway. [ABSTRACT FROM AUTHOR]

Power ultrasound is a kind of green and environmentally friendly processing technology. Still, because of its uneven distribution of acoustic pressure in the propagation medium, the large‐scale industrial application of ultrasound is limited. In order to make more effective use of ultrasound waves, this paper uses a counter‐current ultrasound‐assisted extraction container as the geometric model of simulation, calculates the distribution of the acoustic pressure field in the container by COMSOL Multiphysics software, and investigates the effect of acoustic pressure on the fluid field, and temperature field. The simulation results showed that the acoustic pressure increased with the increase of ultrasound power and frequency, tended to balance with the rise of propagation distance, and the cavitation effect was more likely to occur. The propagation of ultrasound in the fluid medium increased the velocity and vorticity of the fluid, which was conducive to the generation of mixing effects. Under the ultrasound pulse working mode for 4 min, the fluid temperature on the central axis increased in a stepped order, with a maximum increase of 19.3°C. We can see that the establishment of the simulation model provides some theoretical guidance for the more practical application of ultrasound in the food industry. Practical Applications: The limitation of ultrasound application mainly lies in the nonuniform distribution of acoustic pressure when ultrasound propagates in the fluid medium. Therefore, mastering the distribution of multiple physical fields in the reaction zone through simulation has important technical support and theoretical guiding significance for designing efficient ultrasound‐assisted extraction equipment and large‐scale industrial production of ultrasound. [ABSTRACT FROM AUTHOR]

The cavitation bubbles that collapse in the hydraulic machinery can cause damage to the structure and the internal wall. In order to find feasible preventive measures, the mechanism of cavitation bubble collapse needs to be thoroughly studied. However, the influence of the initial radius or the interaction between multi‐bubbles has not been studied in depth. In this paper, the collapse process of single‐ and double‐bubble system is studied by the volume of fluid (VOF) method. Three conditions are considered in this paper, single‐bubble (R0 = 0.3 mm, R0 = 0.4 mm) and double‐bubble system (R0,1 = 0.3 mm and R0,2 = 0.4 mm). The time evolution of pressure, bubble radius, radial velocity, and acceleration during the bubble collapse can be obtained. The bubble collapse time, pressure distribution, and radial velocity of single bubble are verified by theoretical values. It is found that with the increase of bubble initial radius, the collapse, and rebound time is delayed, the maximum pressure of the bubble center increases, the minimum radius of the bubble decreases, the maximum radial velocity increases. In double‐bubble system, during the first rebound of the small bubble, the central pressure, radius and radial velocity of the small bubble fluctuate with time. And the collapse time of each bubble is delayed, the maximum central pressure decreases and the minimum radius of the bubble increases. [ABSTRACT FROM AUTHOR]

Abstract: This paper is devoted to the one‐dimensional (1D) modelling of hydraulic losses during transient flow of liquids in pressure lines. Unsteady pipe wall shear stress is present in the form of a convolution of liquid acceleration with a weighting function. The weighting function depends on the dimensionless time and the Reynolds number. In the original model of Zielke (1968), computation of the convolution integral had a complex and inefficient mathematical structure (featured power growth of computational time). Therefore, further work aimed at developing efficient models for estimation of unsteady hydraulic resistance (with nearly linear growth of computational time). In the present paper, a correction to the erratic recursive formula by Schohl (1993), being used to calculate the unsteady wall shear stresses during transient flow, is presented. The simulation results obtained with the corrected Schohl's recursive formula are consistent with the classic but computationally inefficient formula proposed recently by Vardy and Brown (2010). The accuracy of the efficient weighting function obtained in wall shear stress models is verified. The results of pressure pulsation obtained when taking into account cavitating flow, or not, are surprising in the sense that the weighting function does not need to be built by a lengthy sum of exponential terms to accurately simulate the transient event. [ABSTRACT FROM AUTHOR]

In liquid hydrogen (LH2) delivery, submersible centrifugal pump is an important device. Its reliability and efficiency rely on the stability of the bearings. In a high‐speed range, cavitation occurs due to the hydrodynamic effect induced pressure undulation. Compared with other cryogenic fluids, cavitation in LH2 is prone to happen due to its special properties. In this paper, a cavitation model considering thermal properties of LH2 is proposed based on Rayleigh–Plesset equation. Cavitation characteristics are studied in spiral grooved thrust bearing (SGTB) lubricated by LH2. The effect of cavitation on load capacity and friction torque are investigated. The most severely‐eroded location is predicted by the distribution of mass transfer rate. The influence of bearing structure parameters is studied in respect of cavitation, load capacity and friction torque. The analysis of variance (ANOVA) and range analysis results may provide a reference for optimising LH2 lubricated SGTB. [ABSTRACT FROM AUTHOR]

The force response of squeeze film dampers and hydrodynamic bearings is significantly influenced by the occurence of cavitation inside the lubricant films. The viscosity of the occuring mixture of oil and air bubbles is vastly different than that of pure lubricant and therefore changes the pressure build‐up and thereby the stiffness and damping properties of the lubrication films. To accurately predict the force response of a squeeze film damper, the cavitation and its effect on the pressure build‐up therefore has to be taken into account. Well known cavitation algorithms for lubrication problems, like the Elrod algorithm or the two‐phase‐model, neglect the transient nature of outgassing and assume instantaneous bubble formation and collapse. In the presented paper, a transient bubble dynamics model based on the Rayleigh‐Plesset‐Scriven equation is utilised instead and its effect on the rotordynamic behaviour of a turbocharger rotor is examined based on fully transient multi body dynamics simulations. [ABSTRACT FROM AUTHOR]

In this paper, the Delayed Detached‐Eddy Simulation (DDES) model is used to simulate the cloud cavitation process and the flow field distribution characteristics in the three‐dimensional cavitating chamber with a sudden change channel. The effect of cavitation evolution on the flow field is investigated by the change of vacuole volume fraction and the distribution of physical quantities in the flow field. And the Q criterion is introduced to identify the vortex structure and its variation. The results show that the evolution of cavitation presents periodic characteristics, but in a period, the flow field distribution, vortex structure, and vortex intensity under different cavitation states are different. In the stage of bubble growth, falling off, bubble cluster breaking, and separation, the vortex size is large and the vortex intensity is high, making the flow field show drastic fluctuations. However, in the stage of bubble mass integration, the flow field fluctuation is relatively weak, and the pressure fluctuation law is consistent with the bubble shedding frequency. In addition, the Q criterion indicates that the high‐strength vortices are mainly concentrated in the throat, as the degree of cavitation increases, vortex breakage is intensified and vortices are not obvious in the flow field. [ABSTRACT FROM AUTHOR]

The research on the potential of cavitation exploitation is currently an extremely interesting topic. To reduce the costs and time of the cavitation reactor optimization, nowadays, experimental optimization is supplemented and even replaced using computational fluid dynamics (CFD). One of the approaches towards sustainable water treatment is the use of the cavitation reactor with bluff elements mounted on its stator and rotor. The experimental results show that, besides the rotational speed, the spacing of the rotor pins has the most significant effect on the cavitation intensity and effectiveness, while the pin diameter and the surface roughness are less significant design parameters. The present paper uses a simplified CFD approach to investigate the conditions in the reactor and to select the optimal among a number of geometry variations. [ABSTRACT FROM AUTHOR]

The paper introduces, describes and analyses the specific power oscillations in hydroelectric power plant Dubrava that can appear in large bulb turbines operating with low tailwater levels. The procedure for the identification of the cause of oscillations is described and it is experimentally shown that the cause of power oscillations is a disturbance on a specific runner blade. The physical background of the cavitation‐related phenomena that causes these oscillations is presented. Furthermore, it is shown that neither the automatic voltage regulator nor the transmission network disturbance is the source of oscillations, while the power system stabiliser can only partially damp them. Power oscillations reduce the average power output due to the operation in the unsteady output zone. These oscillations can cause damage to the equipment and reduce its lifespan. The effectiveness of various measures for treatment of these oscillations is discussed. A simple model for simulation of these oscillations is shown and verified against measurements. [ABSTRACT FROM AUTHOR]

The development of phase change models applicable to a wide range of temperatures, pressures, and mass flow rates is primarily limited by the metastable or partially stable behaviour of the fluid. Due to this, the fluid does not change phase even after crossing saturation conditions. Most liquid–vapour phase change models have been developed primarily for the cavitation process where the phase change is not sustained, occurs in a very narrow region of space, or occurs under equilibrium conditions. In this paper, the mechanism of phase change is discussed along with the review of three different computational fluid dynamics (CFD)‐based phase change methods available in OpenFOAM, which are used to simulate flashing of steam, in applications related to steam assisted gravity drainage (SAGD) systems. The first method is based on barotropic compressibility (BC) used with the realizable k−ε turbulence model, the second combination is of mass transfer model (MTM) with the realizable k−ε turbulence model, and the third one is based on two fluid (TF) method along with a family of k−ω turbulence models. These methods are tested on a converging–diverging nozzle with pressure driven phase change. It is demonstrated that these methods are not able to adjust their physics to different depressurization rates, do not account for liquid to be in superheated conditions, and have significant discrepancies with experimental results. In the end, better approaches to model this category of phase change are discussed. [ABSTRACT FROM AUTHOR]

In the paper, the method based on optimization of flow passage geometry of diesel injector nozzle to improve the quality of fuel injection and atomization process has been studied. Designs of injector nozzles have been developed to enhance the quality of these processes. These nozzles' feature is the implementation of local hydraulic resistances—different grooves on the needle tip, which enhance the flow turbulence in the nozzle's flow passage. Computational fluid dynamics (CFD) simulations were performed to study the effect of the nozzle flow passage geometry on parameters of fuel flow, such as mass flow rate, velocity, turbulence, and cavitation. The influence of local hydraulic resistances on the needle tip over these parameters has been evaluated. The optimal geometry of the grooves has been chosen. Experimental studies of a four‐cylinder diesel engine D‐243 equipped with injectors with serial and modified nozzles have been carried out. The possibility of improving the fuel efficiency and emission performances by using the modified nozzles has been confirmed. At the maximum power condition, the use of the modified nozzles reduced the brake‐specific fuel consumption from 275.2 to 270.4 g/(kW∙h) (by 1.7%) and reduced exhaust smoke from 23.5% to 12.5% on the Hartridge scale (by 46.8%). However, at the same time, the emission of NOx increased from 1743 to 1923 ppm (by 10.3%). Moreover, there was a tendency to decrease the content of CO and unburned HC in the exhaust gases. [ABSTRACT FROM AUTHOR]

In this paper, the on‐line small angle X‐ray scattering/wide‐angle X‐ray scattering (SAXS/WAXS) characterization method was adopted to study the morphology evolution of poly(4‐methyl‐1‐pentene) casting films during stretching. In this process, the lamellae structure was destroyed. And "bridge structure" was generated in the amorphous region. The scattering pattern changed obviously before and after cavities orientation. Stretching temperature and stretching speed mattered for the size of micropores. Low temperature helped generate more and larger voids. The faster stretching speed can improve the generation of cavities, enlarged cavitation number and helped its reorientation. These results provide the basic knowledge of how to produce poly(4‐methyl‐1‐pentene) microporous membranes with high electrochemical performance. [ABSTRACT FROM AUTHOR]

In this paper, we present the numerical analysis on high order dual parametric finite element methods for the cavitation computation problems in nonlinear elasticity, which leads to a meshing strategy assuring high efficiency on numerical approximations to cavity deformations. Furthermore, to cope with the high order approximation of the finite element methods, properly chosen weighted Gaussian type numerical quadrature is applied to the singular part of the elastic energy. Our numerical experiments show that the high order dual parametric finite element methods work well when coupled with properly designed weighted Gaussian type numerical quadratures for the singular part of the elastic energy, and the convergence rates of the numerical cavity solutions are shown to be significantly improved as expected. [ABSTRACT FROM AUTHOR]

Many researches were conducted in the past in order to maximise the efficiency of gearboxes, and for many of the sources of power loss, very effective models and tools are already available and can significantly help to optimise the design. Nevertheless, for the load‐independent power losses of gears only in the recent years some progress has been made. Concerning these losses, numerical simulations can help the designers in optimising the internal shape of the casing, thus ensuring the proper lubrication of all the components and reducing the undesired splashing losses. The amount of lubricant plays a fundamental role: A reduction of the lubricant can be critical from the point of view of adequate lubrication and of failures of the system due to wear, scuffing, and pitting but, on the other side, an excessive amount of lubricant leads to additional power dissipation and could even determine an overheating of the system. Another possibility to improve efficiency could be represented by the reduction of the pressure inside the housing: in this paper, the effect of the static pressure on the load‐independent power losses both for complete‐ and dip‐lubrication has been deeply studied. The numerical results, validated by experimental data, show that a reduction up to 15% of the churning losses can be achieved without reducing the amount of lubricant, that is, without increasing the risk of failures related to lubrication. Based on the results obtained, the reduction of the pressure of the housing proves to be a way to improve the efficiency, provided the related engineering issues are also addressed. [ABSTRACT FROM AUTHOR]

This paper presents a revised version of the Coimbra method for recording fibrocartilaginous entheses. The method itself is the only biologically appropriate recording method for fibrocartilaginous entheses that scores features separately, thereby ensuring that the aetiology of individual features can be studied. The method divides the enthesis into two zones, scoring the relevant features in each zone. These features represent either bone formation or bone destruction and include erosive lesions, fine and macro-porosity, and cavitations. The revised method includes a new feature, textural change, which is scored as absent or present when it involves 50% or more of the surface. All other features are now scored as zero (absent), one or two with the higher score representing greater expression of the feature. This change in scoring has led to the reduction of inter-observer error with approximately 80% agreement for overall feature scores for both the common extensor origin and subscapularis insertion. The simplification of the scores and the reduction in inter-observer error mean that the method is now recommended for widespread use. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Previous studies have shown that gel‐spun‐ultra‐high‐molecular‐weight polyethylene (UHMWPE) produces thin fibril products that exhibit high tensile moduli (35–200 GPa). The elaborate gel‐spinning process involves complex drawing stages with solvent incorporation. In this study, a previously proposed two‐stage, environmentally friendly solventless methodology was optimized. The two‐stage process included cross‐rolling (Stage 1) and orientation (Stage 2) to obtain oriented HDPE thin rods with an impressively high modulus using conventional HDPE. The optimization of the process was successfully achieved by thoroughly investigating the voiding mechanism. In addition, rapid relaxation during orientation supports the cavitation mechanism. Owing to this optimization, a modulus of 75 GPa was readily attained. The significant enhancement in the mechanical properties was a direct result of the optimization of our processing methodology to achieve a high degree of orientation. Notably, the fabricated oriented HDPE thin rods showed moduli comparable to those of the gel‐spun UHMWPE fibers but were at least 40 times thicker. Our comprehensive characterization of the voiding process and stress relaxation during our two‐stage process indicated the formation of a highly taut network structure and craze‐like configuration with controlled delamination. Thus, our proposed hierarchical model was refined to elucidate the process‐structure‐property relationships in greater detail. Highlights: An optimized two‐stage environmentally friendly solventless process has been developed to create oriented polyethylene thin rods with impressively high modulus (75 GPa).The optimization was achieved by thoroughly investigating the voiding effect during cross‐rolling and crystalline relaxation during orientation.Comparison of the modulus from our process are similar to various commercial, gel‐spun fibers. Our thin rod products are at least 40 times thicker than commercial gel‐spun fibers.The thin rod product has impressively high modulus‐to‐weight and strength‐to‐weight ratios for future study in composite systems. [ABSTRACT FROM AUTHOR]

Resource allocation theory posits that organisms distribute limited resources across functions to maximize their overall fitness. In plants, the allocation of resources among maintenance, reproduction, and growth influences short‐term economics and long‐term evolutionary processes, especially during resource scarcity. The evolution of specialized structures to divide labor between reproduction and growth can create a feedback loop where selection can act on individual organs, further increasing specializaton and resource allocation. Ferns exhibit diverse reproductive strategies, including dimorphism, where leaves can either be sterile (only for photosynthesis) or fertile (for spore dispersal). This dimorphism is similar to processes in seed plants (e.g., the production of fertile flowers and sterile leaves), and presents an opportunity to investigate divergent resource allocation between reproductive and vegetative functions in specialized organs. Here, we conducted anatomical and hydraulic analyses on Onoclea sensibilis L., a widespread dimorphic fern species, to reveal significant structural and hydraulic divergences between fertile and sterile leaves. Fertile fronds invest less in hydraulic architecture, with nearly 1.5 times fewer water‐conducting cells and a nearly 0.5 times less drought‐resistant xylem compared to sterile fronds. This comes at the increased relative investment in structural support, which may help facilitate spore dispersal. These findings suggest that specialization in ferns—in the form of reproductive dimorphism—can enable independent selection pressures on each leaf type, potentially optimizing spore dispersal in fertile fronds and photosynthetic efficiency in sterile fronds. Overall, our study sheds light on the evolutionary implications of functional specialization and highlights the importance of reproductive strategies in shaping plant fitness and evolution. [ABSTRACT FROM AUTHOR]

Late Woodland period prehistoric human remains recovered from the Hughes site (18MO1) in the 1930s were only recently submitted for bioarcheological analysis. These remains represent 20 individuals exhibiting varying degrees of preservation and representation. Among the remains are several teeth suspected of undergoing antemortem dental modification. All of the examined dental cavitations were deep, and some show excavation all the way to the pulp. Dental remains representing three individuals (two adult females and a child) were examined to define etiology of altered occlusal cavitations in these teeth. The findings provide evidence of prehistoric, therapeutic dentistry in the Middle Atlantic region of the eastern United States. Two mandibles and a maxillary right dental quadrant representing three individuals were analyzed utilizing radiographs, visible and alternate light source macro photography, and scanning electron microscopy in three modes of detection. All three specimens showed signs of both radial and concentric tool marks to varying degrees in both enamel and dentin borders of carious lesions. The shape of the cavitations do not follow normal pathological patterns of undisturbed occlusal decay in teeth. Further, evidence is presented that the excavative tool motion changes from rotational drilling to radial scooping the further posterior the cavitation is located in the oral cavity. Lastly, it is proposed that the reason for these modifications was therapeutic dentistry. [ABSTRACT FROM AUTHOR]

Pneumatic seismic sources, commonly known as airguns, have been serving us well for decades, but there is an increasing need for sources with improved low‐frequency signal and reduced environmental impact. In this paper, we present a new pneumatic source that is designed to achieve these goals by operating with lower pressures and larger volumes. The new source will release more air creating larger bubbles with longer bubble periods than airguns. The release of the air will be tuned so that the rise time will be longer and the sound pressure level and its slope will be lower. Certain engineering features will eliminate cavitation. Larger bubbles increase low‐frequency content of the signal, longer rise times decrease mid‐frequency content and the elimination of cavitation reduces high‐frequency content. We have not yet built a full‐scale version of the new source. However, we have manufactured a small‐scale low‐pressure source incorporating most of the engineering features, and tested it in a lake. Here, we present the lake data that, as expected, show a significant reduction in the sound pressure level, increase in rise time, decrease in slope and decrease in high‐frequency content while maintaining the same low‐frequency content when the source prototype is operated at low pressure compared with high pressure. Synthetic data produced by numerical modelling of the full‐scale proposed pneumatic source suggest that the new source will improve the low‐frequency content and can produce geophysically useful signal down to 1 Hz. [ABSTRACT FROM AUTHOR]

In recent decades, ultrasound has been broadly employed in different applications, particularly in the chemical industry. Ultrasound enhances chemical reactions in a solution via generation of cavitation microbubbles. It improves mass transfer rate and kinetic rate of targeted systems under various process conditions. In polyethylene glycol (PEG) production, the neutralization reaction is generally carried out by employing a mechanical stirring operation. However, this process produces a soluble salt containing potassium and acetate ions, which are known to appreciably manipulate/alter the properties of PEG. In this paper, ultrasound influence is initially analyzed through the neutralization of deionized water. This study then focuses on the neutralization of PEG using ultrasonic cavitation and its impact on the properties of PEG. The ultrasonic cavitation unit employed in this research is a COLE‐Parmer® 500 W & 20 kHz with an ultrasonic probe. To investigate the efficiency of the ultrasonic cavitation reactor and analyze the important aspects of the implemented method, the concentration of soluble salts and conductivity of PEG neutralized by the ultrasonic cavitation method are measured and compared with those of the commercial PEG prepared by the mechanical stirring methodology. The results reveal that the neutralization reaction via the ultrasonic cavitation lowers the conductivity and concentrations of potassium and acetate ions, compared to the traditional stirring methods. It is also concluded that the minimum conductivity and the minimum content of potassium and acetate ions are achieved at 30 % power and a reaction time of 5 min. This study promises the efficient utilization of the ultrasonic cavitation in the industrial sectors, particularly in pharmaceutical industries. [ABSTRACT FROM AUTHOR]

Summary: Since development of cavity expansion theory and strain path method, almost all the conventional analyses of pile penetration problem have been based on circular cross section penetrometer. However, noncylindrical pile (with noncircular cross section) is also required in geotechnical engineering such as rectangular cross‐sectional pile, X‐sectional cast‐in‐place concrete pile, H‐shaped steel pile, prefabricated vertical drains, and flat dilatometer. This paper presents a novel and general analytical approach for capturing the soil deformation mechanism around the pile with arbitrary cross section. The penetration problem is simulated by a new 2‐dimensional (radial and circumferential) cavity expansion model. Based on the theoretical framework of strain path method, the kinematics (velocity field) of the noncylindrical cavity expansion is reduced to solve the Laplace equation with arbitrary velocity boundary conditions by using the conformal mapping technique. Then, solutions for the strain and displacement, which could consider the large deformation effect, are obtained by the integration of the strain rate and velocity along the streamline. The analytical solution is validated by comparing the degenerate solution of this study with conventional circular (cylindrical) cavity expansion theory. Subsequently, typical numerical examples for the deformation mechanism of elliptical and rectangular cavity expansion are presented to prove the advantage of the proposed new solution particularly in capturing the noncylindrical symmetric displacement field. A brief application of the proposed new analytical solution to the interpretation of the smear effect of prefabricated vertical drain installation confirms its useful in geotechnical engineering. [ABSTRACT FROM AUTHOR]

Abstract: Plant adaptation to drought has been extensively studied at many scales from ecology to molecular biology across a large range of model species. However, the conceptual frameworks underpinning the definition of plant strategies, and the terminology used across the different disciplines and scales are not analogous. ‘Drought resistance’ for instance refers to plant responses as different as the maintenance of growth and productivity in crops, to the survival and recovery in perennial woody or grassland species. Therefore, this paper aims to propose a unified conceptual framework of plant adaptive strategies to drought based on a revised terminology in order to enhance comparative studies. Ecological strategies encapsulate plant adaptation to multidimensional variation in resource variability but cannot account for the dynamic and short‐term responses to fluctuations in water availability. Conversely, several plant physiological strategies have been identified along the mono‐dimensional gradient of water availability in a given environment. According to a revised terminology, dehydration escape, dehydration avoidance, dehydration tolerance, dormancy, and desiccation tolerance are clearly distinguishable. Their sequential expression is expressed as water deficit increases while cavitation tolerance is proposed here to be a major hydraulic strategy underpinning adaptive responses to drought of vascular plants. This continuum of physiological strategies can be interpreted in the context of the ecological trade‐off between water‐acquisition vs. water‐conservation, since growth maintenance is associated with fast water use under moderate drought while plant survival after growth cessation is associated with slow water use under severe drought. Consequently, the distinction between ‘drought resistance’ and ‘drought survival’, is emphasized as crucial to ensure a correct interpretation of plant strategies since ‘knowing when not to grow’ does not confer ‘drought resistance’ but may well enhance ‘drought survival’. This framework proposal should improve cross‐fertilization between disciplines to help tackle the increasing worldwide challenges that drought poses to plant adaptation. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of surface texturing in a partial pad journal bearing through a series of controlled experiments at operating conditions, promoting mixed or boundary regimes of lubrication. Improvements to load carrying capacity are observed under certain operating conditions. A comprehensive computational finite volume multiphase fluid dynamics analysis, including vapour transport equation and modified finite-size cavity Rayleigh-Plesset model, is used to study the effect of indented surface textures in the microscale contact domain and within the individual textures themselves. The results show improved conditions with a textured journal through promotion of micro-hydrodynamic effect, delaying the effect of lubricant rupture, thus extending the effective load bearing region. A very good agreement is obtained between measurements and predictions. [ABSTRACT FROM AUTHOR]

A novel rotational hydrodynamic cavitation device (called WLAC, composed of rotor and stator) was designed for treatment of wastewater, as well as two other structures with different lead angle based on WLAC, namely, LLAC and HLAC. The velocity characteristics, cavitation number, cavitation bubbles distribution, and production capacity of the hydrodynamic cavitation device were analyzed. Experimental results showed that the concentration of ·OH increased with treatment capacity as the water was decomposed into ·OH and ·H due to cavitation, which indicated the feasibility of the designed cavitation. The high velocity was mainly distributed around movable teeth and decreased to both sides in WLAC but was distributed between the groove of fixed teeth in LLAC and HLAC, as well as the cavitation region. Meanwhile, the cavitation intensities of HLAC and LLAC were significantly higher than WLAC; especially, the cavitation bubbles generated by HLAC were 54% higher than those generated by WLAC. In addition, the production capacity of hydrodynamic cavitation device decreased with the increase of Re. Due to the stronger capability of cavitation cloud generation and suppression of short circuit flow, the HLAC had higher production capacity of cavitation. The results presented here may provide a workable reference regarding the cavitation generation mode on higher cavitation performance and production capacity for wastewater treatment. [ABSTRACT FROM AUTHOR]

The cavitation technique with the use of a proper hydrogen donor can be used to upgrade heavy oils, such as atmospheric and vacuum residues and lower the difficulties of their transportation and exploitation. On the other hand, the very high localized temperature experienced in collapsing bubbles may activate the dispersed metal nanoparticles, and therefore the cracking or hydrogenation reactions may be catalyzed through the cavitation process of heavy oils. This paper investigated numerically the formation of a vapour phase in the cavitation chamber of a home-made laboratory hydrodynamic cavitation setup and also investigated the upgrading of a sample of heavy fuel oil in the presence of gasoline as a hydrogen donor and metal nanoparticles. The results indicated that adding 0.01 L/L gasoline to a 10-min cavitational cracking process at 80 °C and atmospheric pressure can reduce the viscosity of heavy oil by about 20 %. In addition, the presence of iron nanoparticles can increase the rate of hydrogenation and/or cracking reactions in the heavy oil cavitational upgrading process (HCUP) in the presence of a hydrogen donor. [ABSTRACT FROM AUTHOR]

Slider bearing performance depends on the boundary conditions at the interface between the solid surfaces and the fluid. This paper presents the combined effect of pockets and boundary slip on the load support and friction of parallel sliding systems using analytical solutions for a simple pocketed bearing. The effect of cavitation was of particular interest with respect to the inlet suction mechanism. It was demonstrated that applying boundary slip in a pocketed slider bearing gives a reduction in load support compared with the textured bearing without wall slip. Adding slip over the whole surface could retard the presence of cavitation. The influence of boundary slip is explored, and was found to significantly affect the frictional behaviour. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Thin lubricant films and cavitation to ring-bore contact have a directly correlation between wear and emissions output of internal combustion engines. Thus, there is a need to develop innovate engineering solutions such as surface texturing. In particular, micro textures are manufactured in order to keep more lubricant in weakly lubricated contact. An isothermal mixed-hydrodynamic analysis was developed for textured compression rings, which utilised the effects of two-phase flow using Navier-Stokes equations, vapour transport and asperity interaction. Realistic boundary conditions are used from a real motorbike engine. This paper employs a computational model including multiphase flow of the ring-bore conjunction in order to predict the effects of surface texturing of the barrel face ring around the dead centres. The model is validated using numerical and experimental results from the literature. Additionally, flow simulations have been performed, on how micro-dimples shape and depth on the ring liner affect on the total friction and minimum lubricant film. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Purpose: The inverse planning of an intensity-modulated radiation therapy (IMRT) treatment requires decisions regarding the angles used for radiation incidence, even when arcs are used. The possibility of improving the quality of treatment plans by an optimized selection of the beam angle incidences--beam angle optimization (BAO)--is seldom done in clinical practice. The inclusion of noncoplanar beam incidences in an automated optimization routine is even more unusual. However, for some tumor sites, the advantage of considering noncoplanar beam incidences is well known. This paper presents the benefits of using a derivative-free multistart framework for the optimization of the noncoplanar BAO problem. Methods: Multistart methods combine a global strategy for sampling the search space with a local strategy for improving the sampled solutions. The proposed global strategy allows a thorough exploration of the continuous search space of the highly nonconvex BAO problem. To avoid local entrapment, a derivative-free method is used as local procedure. Additional advantages of the derivative-free method include the reduced number of function evaluations required to converge and the ability to use multithreaded computing. Twenty nasopharyngeal clinical cases were selected to test the proposed multistart framework. The planning target volumes included the primary tumor, the high and low risk lymph nodes. Organs-at-risk included the spinal cord, brainstem, optical nerves, chiasm, parotids, oral cavity, brain, thyroid, among others. For each case, a setup with seven equispaced beams was chosen and the resulting treatment plan, using a multicriteria optimization framework, was then compared against the coplanar and noncoplanar plans using the optimal beam setups obtained by the derivative-free multistart framework. Results: The optimal noncoplanar beam setup obtained by the derivative-free multistart framework leads to high quality treatment plans with better target coverage and with improved organ sparing compared to treatment plans using equispaced or optimal coplanar beam angle setups. The noncoplanar treatment plans achieved, e.g., an average reduction in the mean dose of the oral cavity of 6.1 Gy and an average reduction in the maximum-dose of the brainstem of 7 Gy when compared to the equispaced treatment plans. Conclusions: The noncoplanar BAO problem is an extremely challenging multimodal optimization problem that can be successfully addressed through a thoughtful exploration of the continuous highly nonconvex BAO search space. The proposed framework is capable of calculating high quality treatment plans and thus can be an interesting alternative toward automated noncoplanar beam selection in IMRT treatment planning which is nowadays the natural trend in treatment planning. [ABSTRACT FROM AUTHOR]

Understanding the key steps that drive the laser‐based synthesis of colloids is a prerequisite for learning how to optimize the ablation process in terms of nanoparticle output and functional design of the nanomaterials. Even though many studies focus on cavitation bubble formation using single‐pulse ablation conditions, the ablation efficiency and nanoparticle properties are typically investigated under prolonged ablation conditions with repetition rate lasers. Linking single‐pulse and multiple‐pulse ablation is difficult due to limitations induced by gas formation cross‐effects, which occur on longer timescales and depend on the target materials' oxidation‐sensitivity. Therefore, this study investigates the ablation and cavitation bubble dynamics under nanosecond, single laser pulse conditions for six different bulk materials (Au, Ag, Cu, Fe, Ti, and Al). Also, the effective threshold fluences, ablation volumes, and penetration depths are quantified for these materials. The thermal and chemical properties of the corresponding bulk materials not only favor the formation of larger spot sizes but also lead to the highest molar ablation efficiencies for low melting materials such as aluminum. Furthermore, the concept of the cavitation bubble growth linked with the oxidation sensitivity of the ablated material is discussed. With this, evidence is provided that intensive chemical reactions occurring during the very early timescale of ablation are significantly enhanced by the bubble collapse. [ABSTRACT FROM AUTHOR]

This paper was an application of our previous study on particle coagulation mechanism (Colloid Polym Sci 291: 2385-2398, 2013), and the effect of coagulation particle of acrylic impact modifiers (ACR) on polymer blend properties was investigated. The compatibility was relevant with the properties of shell phase rather than the structure of core phase. The rubber content was found to be the main influencing factor for toughening when rubber content less than 5%. However, when it reached to 7%, the dispersion of rubber became the primary parameter to dominate the toughness. The highest impact strength of poly(vinyl chloride) (PVC) toughened by coagulation particles was 1656 J/m, nearly 56 times than pure PVC, whereas only 45 times was reached when toughening by traditional ACR prepared by seeded emulsion polymerization; moreover, the brittle-ductile transition happened in advanced of 2 phr at ACR content. Scanning electron microscopy results showed that the shear yielding of the matrix and rubber cavitation were the major toughening mechanisms. Furthermore, the high performance of blend responsible for coagulation particles was discussed. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

SUMMARY The present paper extends an established Riemann-based finite volume hydrocode for compressible pure water to admit change of phase. The thermal and caloric behaviour of water and water vapour is described by a one-fluid model on the assumption that the two-phase regime can be described locally within a finite volume cell as a homogeneous mixture that remains in thermodynamic equilibrium. Closure of the equation set is achieved by deriving equations of state for pure fluids and the mixture that cover all possible fluid states. Following a description of the flow model and the numerical method, computations are carried out to demonstrate the potential of the method. Calculations include a one-dimensional cavitation tube, one-dimensional condensation front, collapse of a cavitation bubble in water in one dimension, and an unsteady two-dimensional hypervelocity flow past a cavitating hydrofoil. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper reports the application of two commercial codes to the study of distinct cardiovascular problems: dynamics of a mechanical heart valve prosthesis and function of a native venous valve. The choice of code is driven by the characteristics of the problem. The ANSYS-CFX implicit finite volume code is employed for the mechanical valve where the solution is dominated by the interaction between the local fluid domain and the rigid valve leaflets. The LS-DYNA explicit dynamics code is used due to the stability of this approach when applied to systems with very flexible structural components such as the leaflets of a venous valve. The mechanical valve dynamics remain consistent for a range of mesh densities and residual criteria but begin to vary once the solution time step is increased above 2E-4 s. Venous valve function after application of a gravitational body load is shown to be dependent on parent vessel elastic modulus, E. The venous valve initially closes to a greater extent with a 'softer' parent vessel. Both approaches show promise for further study of these biomedical systems including the cavitation and thrombotic potential of mechanical valves and the local residence of blood constituents in the region of venous valve sinuses. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The article discusses water transport in angiosperms and conifers, focusing on structural factors that influence a plant's resistance to xylem cavitation. Such cavitation increases resistance to water flow, places limits on gas exchange, and may lead to starvation or death of the plant. The paper describes the geometry, material components, and functions of the xylem. It notes that pit membranes facilitate water flow between cells, but restrict passage of gases and pathogens. The pit membranes also account for a large proportion of the hydraulic resistance exhibited by the xylem.

The pressure distribution in hydrodynamic journal bearings is usually calculated by the Reynolds fluid film equation, a linear elliptical partial differential equation. Applying appropriate boundary conditions, e.g., Reynolds boundary conditions, the governing boundary value problem becomes nonlinear. For solving this nonlinear boundary value problem, there exist several established methods. The paper at hand presents an alternative approach using an ALE (Arbitrary Lagrangian Eulerian) formulation. [ABSTRACT FROM AUTHOR]

Abstract Background: The ultrasonic dental scaler is a valuable tool in the prevention of periodontal disease; however, this equipment has a number of hazards with which it is associated. These include heating of the tooth during scaling, vibrational hazards causing cell disruption, possible platelet damage by cavitation, associated electromagnetic fields that can interrupt pacemakers, auditory damage to patient and clinician and the release of aerosols containing dangerous bacteria. Objective: To collate the research reported on the various hazards associated with the ultrasonic dental scaler and discuss possible future research areas. Data Sources: The scientific literature was searched using Web of Science, EMBASE and Medline, and the results of these were then hand-searched to eliminate nonrelevant papers. Conclusions: This review outlines some of the research conducted into these areas of associated hazard in order to assess their significance in the clinical situation, and discusses ideas for future research. Suggestions of recommendations are given, which have been previously investigated for their aid in reducing possible hazards, to ensure the safe working of ultrasonic scalers in the dental practice. [ABSTRACT FROM AUTHOR]

ABSTRACTThis paper discusses the essentials of the oil-filled pressure probe technique in the measurement of negative xylem pressures, focusing in particular on the technique and physics underlying our recent, successful experiment which has rekindled the debate on the validity of the Cohesion–Tension theory. We illustrate a number of general problems associated with the cell pressure probe and xylem pressure probe techniques, and propose appropriate criteria for micropipette construction. We enumerate factors dealing with the cavitation problem and suggest methods for eliminating air seeds in the system. We introduce reliable criteria for the successful measurement of xylem pressure, and emphasize the importance of the probe pressure relaxation test. Several problems regarding the controversy over the Cohesion–Tension theory are also discussed. We discuss the correlation between xylem pressure and the transpiration rate, the existence of absolute negative xylem pressure in intact plants, the most negative values of xylem pressure measured by the pressure probe, the agreement between the pressure probe and pressure bomb techniques, and the vulnerability to cavitation (tensile strength) of pressure probes. [ABSTRACT FROM AUTHOR]

We have previously applied ultrasound (US) with microbubbles (MBs) to enhance inner ear drug delivery, with most experiments conducted using single‐frequency, high‐power density US, and multiple treatments. In the present study, the treatment efficacy was enhanced and safety concerns were addressed using a combination of low‐power‐density, single‐transducer, dual‐frequency US (ISPTA = 213 mW/cm2) and MBs of different sizes coated with insulin‐like growth factor 1 (IGF‐1). This study is the first to investigate the drug‐coating capacity of human serum albumin (HSA) MBs of different particle sizes and their drug delivery efficiency. The concentration of HSA was adjusted to produce different MB sizes. The drug‐coating efficiency was significantly higher for large‐sized MBs than for smaller MBs. In vitro Franz diffusion experiments showed that the combination of dual‐frequency US and large MB size delivered the most IGF‐1 (24.3 ± 0.47 ng/cm2) to the receptor side at the second hour of treatment. In an in vivo guinea pig experiment, the efficiency of IGF‐1 delivery into the inner ear was 15.9 times greater in animals treated with the combination of dual‐frequency US and large MBs (D‐USMB) than in control animals treated with round window soaking (RWS). The IGF‐1 delivery efficiency was 10.15 times greater with the combination of single‐frequency US and large size MBs (S‐USMB) than with RWS. Confocal microscopy of the cochlea showed a stronger distribution of IGF‐1 in the basal turn in the D‐USMB and S‐USMB groups than in the RWS group. In the second and third turns, the D‐USMB group showed the greatest IGF‐1 distribution. Hearing assessments revealed no significant differences among the D‐USMB, S‐USMB, and RWS groups. In conclusion, the combination of single‐transducer dual‐frequency US and suitably sized MBs can significantly reduce US power density while enhancing the delivery of large molecular weight drugs, such as IGF‐1, to the inner ear. [ABSTRACT FROM AUTHOR]

Fibrosis is a disease that involves an abnormal accumulation of extracellular matrix material such as collagen, leading to organ failure. This type of organ failure accounts for around one‐third of all deaths worldwide. However, since there are no drugs which are curative for this disease, the development of non‐invasive treatment strategies is important. In this study, we developed a method of softening fibrotic tissue using non‐converging ultrasound irradiation, a non‐thermal treatment. The generation of cavitation in a standing wave caused the mechanical strength of the fibrotic tissue to decrease in an irradiation time‐dependent manner. The appearance of the fibrous tissue also changed after irradiation, possibly due to the fracture of collagen fibers by ultrasonic cavitation. This method has the potential to treat a wide range of fibrotic tissues. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Summary: The propagation of xylem embolism throughout the root systems of drought‐affected plants remains largely unknown, despite this process being comparatively well characterized in aboveground tissues.We used optical and X‐ray imaging to capture xylem embolism propagation across the intact root systems of bread wheat (Triticum aestivum L. 'Krichauff') plants subjected to drying. Patterns in vulnerability to xylem cavitation were examined to investigate whether vulnerability may vary based on root size and placement across the entire root system.Individual plants exhibited similar mean whole root system vulnerabilities to xylem cavitation but showed enormous 6 MPa variation within their component roots (c. 50 roots per plant). Xylem cavitation typically initiated in the smallest, peripheral parts of the root system and moved inwards and upwards towards the root collar last, although this trend was highly variable.This pattern of xylem embolism spread likely results in the sacrifice of replaceable small roots while preserving function in larger, more costly central roots. A distinct pattern of embolism‐spread belowground has implications for how we understand the impact of drought in the root system as a critical interface between plant and soil. [ABSTRACT FROM AUTHOR]

The underwater muzzle flow field formed by the double‐tube launch will interfere with each other, resulting in large changes in the characteristic parameters of the flow field and shock wave morphology. Therefore, the numerical model of three‐dimensional unsteady multiphase flow for underwater gun‐sealed launching was established. Meanwhile, an experimental platform for the underwater sealed launch was built and the rationality of the model was verified. The interior ballistic process compiled by UDF was coupled with the dynamic mesh technology, and the VOF multiphase flow model integrated with the Schnerr‐Sauer cavitation model was chosen to numerically calculate the muzzle flow field of the 30 mm underwater gun double‐tube parallel launch, and the numerical results were compared to those of the single‐tube launch. The results show that the gas is expelled from the muzzle and rapidly expands to form a gas cavity, and the "necking" phenomenon of the gas cavity occurs at 0.2 ms, while the Mach disk structure has formed. Due to the mutual interference between the flow fields formed by each tube, the diameters of the Mach disk are slightly different, and the flow field structure has a certain asymmetry in the evolution process. The core area of the shock wave is bowl‐shaped of the single‐tube launch, while it is not completely filled of the double‐tube launch. Within 0.5 ms, the diameter of the Mach disk increases monotonously when the single‐tube is launched, while it first increases and then decays by a double‐tube. [ABSTRACT FROM AUTHOR]

In this paper, we study a moving free boundary problem related to the cavitation modeling in lubricated devices. More precisely, a characteristics method combined with a weak formulation in a mixed form is introduced for the Elrod-Adams model. The formulation is suitable for the use of mixed finite element methods in the numerical approximation. It is proved that the time-discrete problem and its finite element discretization have unique solutions. Further an efficient primal-dual active-set strategy is proposed to solve the resulting algebraic system. The performance of the overall algorithm is illustrated by numerical examples. [ABSTRACT FROM AUTHOR]

This paper presents a numerical study of cryogenic fluid flow cavitation in a microchannel and annulus, with forward-facing step. Two-phase mixture model is used to simulate the effects of magnetic fields produced by an electrical wire and magnetic doublet on the cavitation region. The results show that considerable reduction of vapor generation due to pressure drop is possible in the presence of an external magnetic fields. This phenomenon occurs due to effect of magnetic field on the pressure distribution in the contraction region and it is observed in both types of studied magnetic fields. [ABSTRACT FROM AUTHOR]

Thanks to the recent developments in the computer science, simulations are becoming an increasingly widespread approach that can help the designers in the development of new products. In the specific field of gearboxes, simulations are used mainly for structural evaluations. However, while for the structural design beside the simulations, many analytical methods and international standard are available; for the prediction of the power losses and the efficiency of gears, neither accurate analytical methods nor automated simulation tools are available. The authors work on this topic since years and have developed new methodologies based on computational fluid dynamics. With respect to general purpose commercial software, these techniques allow a significant reduction of the computational effort and have the capability to take into account particular physical phenomena that occurs in gears, such as cavitation, and for which no information are available in literature. The purpose of this paper is to introduce a new automated mesh-partitioning strategy implemented to extend the applicability of the previously developed computational effort reduction method to complex gearboxes getting over the geometrical limitations adopted in the past. To show the capabilities of this new strategy, we simulated a planetary gearbox that represents at the same time one of the most complicated kinematic arrangements of gears and the configuration for which the numerical fluid dynamics simulation can give the major contribution both with planar simplified models as well as with complete 3D models. [ABSTRACT FROM AUTHOR]

In this paper, we have reviewed how the hydraulic design of trees influences the movement of water from roots to leaves. The hydraulic architecture of trees can limit their water relations, gas exchange throughout the crown of trees, the distribution of trees over different habitats and, perhaps, even the maximum height that a particular species can achieve. Parameters of particular importance include: (1) the vulnerability of stems to drought-induced cavitation events because cavitation reduces the hydraulic conductance of stems, (2) the leaf specific conductivity of stems because it determines the pressure gradients and most negative water potentials needed to sustain evaporation from leaves, (3) the water storage capacity of tissues because this might determine the ability of trees to survive long drought periods. All of these parameters are determined by the structure and function of anatomical components of trees. Some of the ecological and physiological trade-offs of specific structures are discussed. [ABSTRACT FROM AUTHOR]

Cavitation resistance has often been viewed as a relatively static trait, especially for stems of forest trees. Meanwhile, other hydraulic traits, such as turgor loss point (Ψtlp) and xylem anatomy, change during the season. In this study, we hypothesized that cavitation resistance is also dynamic, changing in coordination with Ψtlp. We began with a comparison of optical vulnerability (OV), microcomputed tomography (µCT) and cavitron methods. All three methods significantly differed in the slope of the curve,Ψ12 and Ψ88, but not in Ψ50 (xylem pressures that cause 12%, 88%, 50% cavitation, respectively). Thus, we followed the seasonal dynamics (across 2 years) of Ψ50 in Pinus halepensis under Mediterranean climate using the OV method. We found that Ψ50 is a plastic trait with a reduction of approximately 1 MPa from the end of the wet season to the end of the dry season, in coordination with the dynamics of the midday xylem water potential (Ψmidday) and the Ψtlp. The observed plasticity enabled the trees to maintain a stable positive hydraulic safety margin and avoid cavitation during the long dry season. Seasonal plasticity is vital for understanding the actual risk of cavitation to plants and for modeling species' ability to tolerate harsh environments. Summary Statement: Shoot xylem vulnerability of Pinus halepensis is a seasonal plastic trait, which adjusts to lower water potential during the summer in coordination with the turgor loss point. [ABSTRACT FROM AUTHOR]

To mitigate poor contact issues between electrolyte/electrode materials interfaces of all‐solid‐state batteries (ASSB), we newly introduce a novel solution‐processed synthesis that exploits the differences in the boiling point and polarity of the two solvents (i. e., methanol, and toluene), with a cavitation effect by bubbling inert gas. Through this process, called solvent exchange with bubbles (SEB), the Li6PS5Cl solid electrolyte is synthesized with a particle size below 800 nm and sufficient ionic conductivity of 1.54 mS/cm at 25 °C. In addition, the ASSB cell consisting of the cathode electrode with Li6PS5Cl synthesized by the SEB exhibited a high capacity of 176 mAh/g at 0.1 C (55 °C) owing to the improved contact between the electrode and solid electrolyte. In particular, the rate capability of the cell is superior to that of a cell with Li6PS5Cl prepared by ball milling. [ABSTRACT FROM AUTHOR]

Fluids in narrow gaps are employed frequently in many applications. The motivation for their use is diverse and ranges from hydrodynamic lubrication in plain bearings to the transport of hard particles into the working gap for the purpose of machining workpiece surfaces in lapping processes. Depending on the focus of the analysis, it may be useful to investigate the entire pressure field or to calculate only individual quantities. For example, in sophisticated simulations it may be of interest to know the resulting force of a fluid as a function of the external system state in order to describe its damping characteristics. Especially for the simulation of flows in narrow gaps, the Reynolds equation is a convenient choice, which, in contrast to the more general Navier‐Stokes equations, can lead to considerable savings in computational time because no three‐dimensional discretization is required, but only a two‐dimensional discretization. However, if not a highly detailed pressure field is of interest, but only simple relations such as the resulting force as a function of distance and velocity, and if this relation to be evaluated many times for different parameter combinations over a wide range of values, the use of a robust substitute model is a good choice. This article deals with the creation of such a substitute model based on the Reynolds equation taking cavitation into account. [ABSTRACT FROM AUTHOR]

Summary: Embolism refilling is thought to require relaxation of xylem tension, and it is unclear whether and how tall trees or plants growing in arid or saline soils recover from embolism. We tested whether foliar water uptake could enable embolism refilling in dehydrated twigs of the grey mangrove (Avicennia marina).Four dehydrated twigs were imaged by laboratory‐based micro‐computed tomography before and after wetting leaves.Emboli were observed in dehydrated stems and leaves. Embolism decreased with increasing distance from the cut end of stems, suggesting that stem emboli were caused by cutting. A significant (P = 0.026) c. 80% reduction in the embolised area was observed in leaves between the start and the end of the experiment (29 ± 10 h after wetting). Embolus diameter was unaffected by wetting.Embolism refilling occurred slowly, in stems embolised by cutting and leaves embolised by cutting and/or dehydration. The lack of response of embolus diameter to wetting suggests that capillarity was not the main mechanism for refilling. Results show that excised twigs of A. marina are able to recover from embolism by absorption of atmospheric water and call for studies under natural conditions. [ABSTRACT FROM AUTHOR]

Summary: Disruption of photosynthesis and carbon transport due to damage to the tree crown and stem cambial cells, respectively, can cause tree mortality. It has recently been proposed that fire‐induced dysfunction of xylem plays an important role in tree mortality. Here, we simultaneously tested the impact of a lethal fire dose on nonstructural carbohydrates (NSCs) and xylem hydraulics in Pinus ponderosa saplings.Saplings were burned with a known lethal fire dose. Nonstructural carbohydrates were assessed in needles, main stems, roots and whole plants, and xylem hydraulic conductivity was measured in the main stems up to 29 d postfire.Photosynthesis and whole plant NSCs declined postfire. Additionally, all burned saplings showed 100% phloem/cambium necrosis, and roots of burned saplings had reduced NSCs compared to unburned and defoliated saplings. We further show that, contrary to patterns observed with NSCs, water transport was unchanged by fire and there was no evidence of xylem deformation in saplings that experienced a lethal dose of heat from fire.We conclude that phloem and cambium mortality, and not hydraulic failure, were probably the causes of death in these saplings. These findings advance our understanding of the physiological response to fire‐induced injuries in conifer trees. [ABSTRACT FROM AUTHOR]

Reconciling discrepancies in measurements of vulnerability to xylem embolism with the pneumatic method: A comment on Chen et al. (2021) 'Quantifying vulnerability to embolism in tropical trees and lianas using five methods: can discrepancies be explained by xylem structural traits? They argue that the pneumatic method, which quantifies the relative increasing volume of air discharged from embolized regions of a branch's xylem (relative to a maximum amount of air discharged, AD SB max sb ) as the branch is dehydrated in the laboratory, underestimates I P i SB 50 sb and therefore xylem embolism resistance. By contrast, when Chen I et al i . used nonpneumatic methods, they estimated the embolism resistance using the maximum amount of embolized vessels taken at more negative xylem water potentials (frequently more negative than -6.5 MPa). When we refitted the embolism vulnerability curves scaled by AD SB max sb values that were successively less than the best estimate AD SB max.ref sb , the correspondingly estimated I P i SB 50 sb values were systematically lower in magnitude, on average, than the best estimate ( I P i SB 50.ref sb ), as seen for each of the nine species (Figs 2, S3). [Extracted from the article]