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Polymer membranes with narrow pore size distribution have received considerable attention because of their high-resolution and high-efficiency separation performance. By elaborately adjusting the parameters in the membrane formation process, we fabricated self-assembled perforated membranes with a series of pore diameters via the breath figure method. The membranes have very narrow pore size distribution and can be considered isoporous membranes. Membranes with controllable surface chemistry were further achieved by dopamine chemistry. The separation performance of the membranes was systematically investigated under different external pressures. We found that yeast cells can pass through the membranes with a pore diameter smaller than the cell size under a relatively high operating pressure. The isoporous membranes were also applied to the separation of cell mixtures such as yeasts and lactobacilli. A very high flux is obtained under a pressure of as low as 0.004 MPa. Moreover, yeast cells are completely separated from lactobacilli with a rejection ratio of about 100%. The self-assembled isoporous membranes can also be applied in other size-based separation systems with excellent separation performance and reusability, enabling new opportunities in fields such as bio-separation and biosensors.

Cu2GeS3 and Cu2SnS3 crystalline samples with monoclinic (space group Cc) structures were fabricated using Bridgman method. The lattice constants, determined from the powder X-ray diffraction pattern, were a = 6.44 A, b = 11.30 A, c = 6.42 A, and β = 108.44° for Cu2GeS3 and a = 6.65 A, b = 11.57 A, c = 6.66 A, and β = 109.30° for Cu2SnS3. Cu2GeS3 exhibited eight Raman-active vibration modes at 255 cm−1, 281 cm−1, 299 cm−1, 317 cm−1, 339 cm−1, 359 cm−1, 397 cm−1, and 422 cm−1, while Cu2SnS3 showed only four modes at 294 cm−1, 316 cm−1, 354 cm−1, and 374 cm−1 at ambient conditions. The Raman spectra were also measured at pressures up to 5.31 GPa, and the effects of high pressure on the observed Raman modes were discussed.

The dimer Mott insulator $\ensuremath{\kappa}\text{\ensuremath{-}}{(\mathrm{BEDT}\text{\ensuremath{-}}\mathrm{TTF})}_{2}{\mathrm{Cu}}_{2}{(\mathrm{CN})}_{3}$ can be tuned into metallic and superconducting states on applying pressure of 1.5 kbar and more. We have performed dielectric measurements (7.5 kHz to 5 MHz) on $\ensuremath{\kappa}\text{\ensuremath{-}}{(\mathrm{BEDT}\text{\ensuremath{-}}\mathrm{TTF})}_{2}{\mathrm{Cu}}_{2}{(\mathrm{CN})}_{3}$ single crystals as a function of temperature (down to $T=8$ K) and pressure (up to $p=4.3$ kbar). In addition to the relaxor-like dielectric behavior seen below 50 K at $p=0$, that moves toward lower temperatures with pressure, a second peak emerges in ${\ensuremath{\varepsilon}}_{1}(T)$ around $T=15$ K. When approaching the insulator-metal boundary, this peak diverges rapidly reaching ${\ensuremath{\varepsilon}}_{1}\ensuremath{\approx}{10}^{5}$. Our dynamical mean-field theory calculations substantiate that the dielectric catastrophe at the Mott transition is not caused by closing the energy gap, but due to the spatial coexistence of correlated metallic and insulating regions. We discuss the percolative nature of the first-order Mott insulator-to-metal transition in all details.

Within the scope of the present work, the pressure-dependent effective thermal conductivity of rock samples is simulated. Our workflow can be assigned to the field of digital rock physics. In a first step, a 3D micro-CT scan of a rock sample is taken. Subsequently, the resulting greyscale images are analysed and segmented depending on the occurring phases. Based on this data set, a computational mesh is created and the corresponding thermal conductivities are assigned to each phase. Finally the numerical simulations can be carried out.For the representation of the pressure dependency we use the approach proposed by Saenger [1]. By making use of the watershed algorithm, boundaries between the individual grains of the rock sample are detected and assigned to an artificial contact phase. In the course of several simulations, the thermal conductivity of the contact phase is continuously increased. Starting with the thermal conductivity of the pore phase and ending with the thermal conductivity of the grain phase. A linear correlation is used to match the thermal conductivity of the contact phase with the pressure of a given experimental data set. This enables a direct comparison between simulation and measurement.In a further step, the numerical model is calibrated to optimise the agreement between experimental data and simulation results. In particular, starting from two calibration points of the experimental data set, an adjustment of the thermal conductivities in the numerical model is carried out. While the thermal conductivity of the pore phase is held constant during the whole calibration process, thermal conductivities of the grain and contact phase are adjusted.References[1] Saenger et al. 2016. Analysis of high-resolution X-ray computed tomography images of Bentheim sandstone under elevated confining pressures. Geophysical Prospecting, 64(4), 848–859.

Pulse wave velocity (PWV) is a function of the artery’s material property, and its incremental nature in elastic modulus led to the concept of incremental PWV. Recent advancements in technology paved the way for reliable measurement of the variation in PWV within a cardiac cycle. This change in PWV has shown its potential as a biomarker for advanced cardiovascular diagnostics, screening, and has recently started using as a vascular screening tool and medical device development. In this work, we have demonstrated the concept of inter and intra-cycle variations of PWV with pressure using an excised bovine carotid artery. Results demonstrated that local PWV measured at the foot of the waveform followed the same trend as of the pressure. As the pressure level was increased to 68% across the cycles, resulting PWV increased up to 81%. An exponential PWV-Pressure relationship was obtained, in agreement with the widely used models. The incremental nature of PWV was recorded in a reflection-free region of the pressure pulse wave. This was further demonstrated in continuous pulse cycles with varying pressure ranges, by comparing the PWV values at two fiduciary points selected in the upstroke of the pressure wave. On average, a 48.11% increase in PWV was observed for 31.04% increase in pressure between the selected fiducial points within a pulse cycle. The article concludes, highlighting the clinical significance of incremental PWV.Clinical Relevance— This experimental study supplements the evidence for the incremental nature of PWV within a cardiac cycle, which has the potential for being a biomarker for advanced cardiovascular screening and diagnostics.

International audience; This paper extends and improves the Newton algorithm to solve contact and wear problems with pressure-dependent friction coefficients. Especially, the wear problems with pressure-dependent friction coefficients are numerically solved for the first time. The contact forces are calculated by the bipotential method. Combining the calculation steps of contact forces with the local equilibrium equations, the contact and wear problems are described in the local form. The nonlinear equations are solved by a Newton-like algorithm in which the new piecewise continuous contact tangent matrices are explicitly derived. The contact tangent matrices contain the coupled relationship of the friction coefficients and the normal contact pressure. The wear is calculated via the Archard wear law when the global Gauss-Seidel-like iteration is converged. Numerical examples show that different pressure-dependent friction coefficients will affect the pressure distribution, the wear rate and shape of objects, and may result in different wear regimes in some cases.

Under near-vacuum conditions, the fluid frictional dissipation or approximately the inverse of the quality factor of a microcantilever once the intrinsic dissipation can be neglected is proportional to the low pressure. We shall investigate the dynamic behavior of micro-electromechanical systems (MEMS) devices via the calculation of the quality factor or frictional damping forces resulting from surrounding gases. Here, we illustrated some specific examples relevant to the computation of the quality factor or dynamical friction for an oscillating microcantilever in air via measurements of the paper of Okada et al. (Okada, H., Itoh, T., and Suga, T., 2008, Wafer Level Sealing Characterization Method Using Si Micro Cantilevers,” Sens. Actuators A, 147(2), pp. 359–364) considering the quality factors of the CM (a label for a microcantilever: 500 × 90 × 5 μm3 Si microcantilever (the measured resonance frequency: 23.7 kHz) and the paper of Kara et al. (Kara, V., Yakhot, V., and Ekinci, K. L., 2017, Generalized Knudsen Number for Unsteady Fluid Flow, Phys. Rev. Lett., 118(7), p. 074505) in rarefied gases regime. We present the corrected quality factor or dynamical friction over the whole range of the Knudsen number considering the CM part by Okada et al. Our new plot considering the quality factor which is proportional to the inverse of the dissipative friction parameter per unit length, pressure as well as the Knudsen number over the whole range should be useful to researchers in this field.

In this paper we consider the near-tip region of a fluid-driven fracture propagating in permeable rock. We attempt to accurately resolve the coupling between the physical processes – rock breakage, fluid pressure drop in the viscous fluid flow in the fracture and fluid exchange between the fracture and the rock – that exert influence on the hydraulic fracture propagation, yet occur over length scales often too small to be efficiently captured in existing coarse grid numerical models. We consider three fluid balance mechanisms: storage in the fracture, pore fluid leak-in from the rock into the fracture as the result of dynamic suction at the dilating crack tip, and fluid leak-off from the fracture into the rock as the fluid pressure in the fracture recovers with distance away from the tip. This process leads to the formation of a pore fluid circulation cell adjacent to the propagating fracture tip. We obtain the general numerical solution for the fracture opening and fluid pressure in the semi-infinite steadily propagating fracture model, while assuming that the hydraulic fracturing and pore fluids have the same properties. We fully characterise the solution within the problem parametric space and identify different regimes of the fracture propagation. We assess the impact of the pore fluid leak-in and the associated near-tip circulation cavity on the solution and explore limitations of the widely used, pressure-independent Carter’s leak-off model. The obtained solution could be potentially used as a tip element in the finite crack models (penny-shaped, Planar3D), provided that a fast numerical implementation is further elaborated.

A compact, single-pass and low-power-consumption methane sensing system is presented and its sensitivity is investigated for a set of reference cells with pressures of 7.4, 74 and 740 Torr and the same methane concentration of 1351 ppm. A single-mode GaSb-based continuous-wave (CW) distributed feedback (DFB) tunable diode laser at 3270 nm and wavelength modulation spectroscopy were employed to collect 2f spectra in the ν₃,R₃ band of ¹²CH₄. A modulated Voigt line profile model was used to fit the collected 2f spectra. The best detectivity of 4 ppbm is obtained for the highest pressure cell using an Allan-Werle variance analysis., Quantum Sensing and Nano Electronics and Photonics XVII, February 1-6, 2020, San Francisco, US, Series: Proceedings of SPIE

A thermodynamics-based energy analysis approach for pressure-dependent materials is presented. Formulation of plastic free energy and plastic dissipation for the nonassociated Drucker-Prage...

We present a theory of pressure-dependent melting temperature to describe the physical fact that both cooling and pressurization can cause the solidification of liquid metal. Based on the Force-Hea...

The mechanical response of packings of purely repulsive, spherical particles to athermal, quasistatic simple shear near jamming onset is highly nonlinear. Previous studies have shown that, at small pressure $p$, the ensemble-averaged static shear modulus $⟨G\ensuremath{-}{G}_{0}⟩$ scales with ${p}^{\ensuremath{\alpha}}$, where $\ensuremath{\alpha}\ensuremath{\approx}1$, but above a characteristic pressure ${p}^{**}$, $⟨G\ensuremath{-}{G}_{0}⟩\ensuremath{\sim}{p}^{\ensuremath{\beta}}$, where $\ensuremath{\beta}\ensuremath{\approx}0.5$. However, we find that the shear modulus ${G}^{i}$ for an individual packing typically decreases linearly with $p$ along a geometrical family where the contact network does not change. We resolve this discrepancy by showing that, while the shear modulus does decrease linearly within geometrical families, $⟨G⟩$ also depends on a contribution from discontinuous jumps in $⟨G⟩$ that occur at the transitions between geometrical families. For $pg{p}^{**}$, geometrical-family and rearrangement contributions to $⟨G⟩$ are of opposite signs and remain comparable for all system sizes. $⟨G⟩$ can be described by a scaling function that smoothly transitions between two power-law exponents $\ensuremath{\alpha}$ and $\ensuremath{\beta}$. We also demonstrate the phenomenon of compression unjamming, where a jammed packing unjams via isotropic compression.

Modelling interface interaction with wave propagation in a medium is a fundamental requirement for several types of application, such as structural diagnostic and quality control. In order to study the influence of a pressure-dependent interface stiffness on the nonlinear response of contact interfaces, two nonlinear contact laws are investigated. The study consists of a complementary numerical and experimental analysis of nonlinear vibrational responses due to the contact interface. The laws investigated here are based on an interface stiffness model, where the stiffness property is described as a nonlinear function of the nominal contact pressure. The results obtained by the proposed laws are compared with experimental results. The nonlinearity introduced by the interface is highlighted by analysing the second harmonic contribution and the vibrational time response. The analysis emphasizes the dependence of the system response, i.e., fundamental and second harmonic amplitudes and frequencies, on the contact parameters and in particular on contact stiffness. The study shows that the stiffness&ndash, pressure trend at lower pressures has a major effect on the nonlinear response of systems with contact interfaces.

International audience; In this paper a new method is proposed that solves for the steady state of pressure-dependent models (PDMs) with flow control valves. Rather than model flow devices individually, the method solves the more general problem in which a water distribution system (WDS) has some link flows constrained to lie between upper and lower, or possibly equal, set limits. No heuristics are used to determine device states. The method is shown to be fast, and its effectiveness is demonstrated on PDM WDSs with up to about 20,000 links and 18,000 nodes and 60 link flow constraints, some of which prescribe a fixed flow. The method has applications in network management, network design, and flow control to deal with water distribution where there is insufficient supply.

High-pressure Raman scattering from hexagonal close-packed (HCP) metals Os and Re have been extended up to 200 GPa, and the pressure-dependent shear modulus C 44 has been deduced from the Raman-active mode E 2g , which is generated from the adjacent vibration of atoms in hexagonal planes, providing the valuable information about the elastic properties for HCP metals under high pressure. Combined with the available data of HCP metals from previous works, a further study indicates that the C 44 ′ / C 44 ratio would be close to a constant value, 0.01, with increasing atomic number of metals. The results obtained from high-pressure Raman scattering will allow us to probe the elastic anisotropy of the HCP metals at very high pressure.

The formation of NO2− and NO3− in the sonolysis of water under air was investigated to evaluate the chemical properties of collapsing air bubbles that reached high-temperature and high-pressure conditions. The sum of initial rates of NO2− and NO3− formation and the ratio of these rates showed different dependences on ultrasonic power. By analyzing the adiabatic compression equations, it was confirmed that the increment ratio of the bubble pressure was much larger than that of the bubble temperature, suggesting that the bubble pressure affects the chemical reactions occurring in a bubble. Therefore, we analyzed the effect of temperature and pressure on the formation of NO2 and NO, the main precursors of NO3− and NO2−, respectively, using chemical equilibrium calculations to interpret the difference in power dependence. The results suggest that NO2− was formed more easily at higher temperatures, while NO3− formed more easily at higher pressures. We propose that NO2− and NO3− can be used as probes for temperature- and pressure-dependent reactions to improve the understanding of the physicochemical properties of collapsing air bubbles.

Milk inoculated with Clostridium botulinum spores (PA9508B) (107 CFU/mL) was subjected to high-pressure high-temperature treatment (HPHT) (700–900 MPa; 90–110 °C for 0–24 min) using an insulated sample chamber, as well as in a water bath (90–100 °C) (conventional) and surviving spores were enumerated. Destruction kinetics were well described by a first order kinetic model. Conventional heating D values ranged from 156 to 12 min with a z value of 7.8 °C. During HPHT, higher pressures and temperatures resulted in accelerated spore destruction rates. At 900 MPa, the associated D values were 14.5, 1.8 and 0.35 min at 90, 100 and 110 °C, respectively, much lower than the conventional D values. The pressure dependent ZT values were 11.2, 12.3, 12.4 °C at 700, 800, 900 MPa respectively, increasing with pressure. The temperature dependent ZP values were 470, 630, and 800 MPa at 90, 100, and 110 °C, respectively. By comparing ZT with ZP values, it was clear the spores were relatively more sensitive at higher temperatures than at higher pressures in this temperature-pressure range. D value trends beyond 120 °C indicated thermal inactivation was the principal mode of spore destruction and high pressure can protect spores under these conditions.

A water distribution network (WDN) may not be able to satisfy all required demands when it’s in the pressure deficit mode or under over-loaded demand conditions. Analysis of the network in this mode requires pressure dependent analysis (PDA). Unlike demand driven analysis (DDA), PDA needs an extra equation for every node to relate the nodal demand and the nodal pressure; so it should be solved with the other network’s equations simultaneously. In this paper, based on the Particle Swarm Optimization (PSO) algorithm, a decision support system has been developed by using MATLAB and EPANET for PDA simulation in WDNs. A four-loop network selected from the literature was analyzed using different scenarios and different pressure dependent functions presented by the previous investigations. The results showed that the proposed model (PSO-PDA) was as accurate as the previous ones and provided better convergence. The results of the nodes’ pressure and discharge also indicated minor differences obtained by different PDA functions. However, the differences between the results of PDA and DDA were considerable.

We apply our cooperative free volume (CFV) rate model for pressure-dependent dynamics to describe the relaxation times for poly(4-chlorostyrene) (P4ClS) bulk and thin films. The CFV model expresses segmental relaxation times, τ, as a function of temperature, T, and thermodynamic free volume, Vfree = V – Vhc, where the limiting hard core volume, Vhc, is obtained via analysis of a polymer’s experimental PVT data using the locally correlated lattice (LCL) model equation of state. In adapting CFV to describe thin films, we assume that the main effect of confinement is that the interface serves to change the average free volume (average density) compared to bulk. We formulate a simple weighted average expression (involving just a single interface related parameter) to describe the free volume of a film as a function of thickness, h, and use this h-dependent Vfree within the CFV model expression. Using just ambient pressure relaxation time data on bulk P4ClS, along with PVT data, we parametrize the CFV model, w...

To establish the relation between optimum interlayer distance for hydrogen storage and electrical conductance, we measured the electrical conductance (G) of 3-dimensional graphene oxide (GOA) depending on high H2 pressure, from vacuum to 20 bar. The GOA was synthesized using diaminoalkanes with two lengths of alkyl chains, and the interlayer distance of GOA was modulated by thermal annealing. A decrease in G was observed as the H2 pressure increased. The maximum variation in G was observed at 7.0 A of interlayer distance. When the interlayer distance-dependent H2 uptake was considered, we confirmed that the maximum variation in G as well as optimum H2 uptake occurred at the same interlayer distance, 7.0 A. The variation in G due to H2 exposure provides understanding about the behavior of hydrogen molecules on these materials and on the modulation of the electronic structure of the materials.

The paper describes the extension of a previously developed model of pressure-dependent contraction rate to the case of multiple lymphangions. Mechanical factors are key modulators of active lymphatic pumping. As part of the evolution of our lumped-parameter model to match experimental findings, we have designed an algorithm whereby the time until the next contraction depends on lymphangion transmural pressure in the contraction just completed. The functional dependence of frequency on pressure is quantitatively matched to isobaric contraction experiments on isolated lymphatic segments. When each of several lymphangions is given this ability, a scheme for their coordination must be instituted to match the observed synchronisation. Accordingly, and in line with an experiment on an isolated lymphatic vessel segment in which we measured contraction sequence and conduction delay, we took the fundamental principle to be that local timing can be overridden by signals to initiate contraction that start in adjacent lymphangions, conducted with a short delay. The scheme leads to retrograde conduction when the lymphangion chain is pumping against an adverse pressure difference, but antegrade conduction when contractions occur with no or a favourable pressure difference. Abolition of these conducted signals leads to chaotic variation of cycle-mean flow-rate from the chain, diastolic duration in each lymphangion, and inter-lymphangion delays. Chaotic rhythm is also seen under other circumstances. Because the model responds to increasing adverse pressure difference by increasing the repetition rate of contractions, it maintains time-average output flow-rate better than one with fixed repetition rate.

In this paper, the effect of surface roughness and pressure-dependent viscosity over couple-stresses squeeze film lubrication between circular stepped plates is studied. The modified average Reynolds equation is derived for the one-dimensional roughness structures, namely the radial roughness pattern and azimuthal roughness pattern. Modified equations for the nondimensional pressure, load-carrying capacity, and nondimensional squeeze film time are obtained. Also, the obtained results of our study for some special cases are compared with the previously published smooth surface case, and the results are found to be in very good agreement. It is observed that, one-dimensional azimuthal (radial) roughness pattern on the rough circular stepped plate increases (decreases) the load-carrying capacity and the squeeze film time as compared to the smooth case.

The mechanical properties of newly synthesized Ca2C3 and Ca2C under pressure have been studied by using the first-principles calculations with generalized gradient approximation. The equilibrium geometry, elastic stiffness constants, various moduli, and Pugh's ratio of the C2/m phase of Ca2C3 and the C2/m and Pnma phases of CaC2 are systematically studied. The elastic stiffness constants of C2/m-Ca2C3 under 0–30GPa, C2/m-Ca2C under 0–7.5 GPa, and Pnma-Ca2C under 7.5–30 GPa satisfy the Born−Huang mechanical criteria. The three phases of calcium carbides exhibit ductile characteristics. The surface constructions of bulk and Young's moduli illustrate the mechanical anisotropy of Ca2C3 and Ca2C. Our results are consistent with previously obtained experimental and theoretical data and have significant implications for the application of calcium carbides.

The ideal flow theory for pressure-dependent materials is used to calculate an ideal die for plane strain extrusion/drawing. In particular, the double slip and rotation and double shearing model are adopted. Comparison with the available ideal flow solution for pressure – independent material is made. It is shown that the die for pressure-dependent material is shorter than that for pressure-independent material. Moreover, the angle of internal friction has an effect of the distribution of contact pressure.

First-principles calculations have been performed to study the structural, elastic, electronic and lattice dynamical properties of Ba 2 InTaO 6 and Ba 2 InNbO 6 double perovskites under hydrostatic pressure. Pressure-induced enhancements of elastic constants, elastic moduli, elastic wave velocities, as well as Debye temperature are observed, without any softening behaviors. Both Ba 2 InTaO 6 and Ba 2 InNbO 6 have a quasi-direct band-gap character at zero pressure, and their fundamental energy gaps vary nonlinearly with increasing pressure. Moreover, the evolution of Roman-active and infrared-active optical phonon frequencies with pressure is analyzed. A pressure-induced softness of low-frequency T 1 g silent modes around the Γ point suggests that Ba 2 InTaO 6 and Ba 2 InNbO 6 becomes dynamically instable beyond a certain critical pressure.

In tight gas reservoirs, permeability is pressure dependent owing to pore pressure reduction during the life of the reservoir. Empirical models are commonly used to describe pressure-dependent permeability. In this paper, it was discussed a number of issues which centered around tight sandstone pressure-dependent permeability experiment, first to apply core aging on permeability test and then to develop a new semi-analytical model to predict permeability. In tight sandstone permeability test experiment, the microinterstice between core and sleeves resulted in over estimation of dependency of permeability on pressure. Then, a new semi-analytical model was developed to identify the relation between permeability and fluid pressure in tight sandstone, which indicates there is a linear relation between pore pressure changes and the inverse of permeability to a constant power. Pressure-dependent permeability of 8 tight sandstone core samples from Ordos Basin, China, was obtained using the modified procedure, and results were perfectly matched with the proposed model. Meanwhile, the semi-analytical model was also verified by pressure-dependent permeability of 16 cores in the literature and experiment results of these 24 cores were matched by empirical models and the semi-analytical model. Compared with regression result of commonly used empirical models, the semi-analytical model outperforms the current empirical models on 8 cores from our experiment and 16 cores from the literature. The model verification also indicates that the semi-theoretical model can match the pressure-dependent permeability of different rock types. In addition, the permeability performance under reservoir condition is discussed, which is divided into two stages. In most tight gas reservoirs, the permeability performance during production is located in stage II. The evaluation result with proposed experiment procedure and the stress condition in stage II will reduce permeability sensitivity to stress.

Correlation for effective surface area is one of the important input for modeling of gas absorption in countercurrent packed column. Although the correlation previously developed by other researchers was able to provide quite decent prediction of carbon dioxide (CO2) absorption system, improvement still need to be done especially for high pressure condition whereby consideration for the decrease of effective surface area due to severe vapour backmixing situation needs to be taken into account. In this work, pressure dependent correction correlation was developed by incorporating the ratio of liquid to gas densities. The correlation developed in this study was found to successfully improve the prediction trend of the CO2 concentration profile along the column

Chronic kidney disease (CKD) is a global health problem that affects around 11 to 13% of the world’s population and more than 18% of European citizens. Characteristic syndromes of CKD during all stages of the disease are proteinuria and ongoing glomerular dysfunction caused by cellular damages at the glomerular filtration barrier. While some rare cases of the disease are correlated to genetic depositions the majority of cases are caused by diabetes, glomerulosclerosis, high blood pressure and glomerulonephritis. Thus, recapitulating the interplay of high blood pressure and changes at the glomerular filtration barrier in vitro seems an adequate way to mimic CKD. Here we present a microphysiological system of the glomerular filter that is capable to simulate high blood pressure at the glomerular filtration barrier in vitro. It consists of a closed loop microfluidic circuit with an integrated pneumatically driven heart like micro pump that constantly circulates the cell culture media at the blood site of the glomerular barrier. The ThinCert™ insert could be reversibly integrated into a holder system that ensures the correct position of the insert within the microfluidic circuit. By using different modulations of the integrated pneumatic micro pump different physiological and pathophysiological conditions e.g. hypertonic stress, like in CKD, could be applied. The influence of hypertonic conditions on the filtration above the barrier was studied by changes of TEER values and measurement of the flux of fluorescent labelled albumin through the cellular barrier.

We have studied the pressure dependences of the long thrust and specific power thrust of synthetic jets generated by dielectric barrier discharge of a symmetric actuator at reduced pressures. Decreasing pressure leads to increase in the length of the plasma sheet. The thrust of synthetic jets reaches a maximum at a certain pressure dependent on the actuator geometry.

The pressure dependent behaviors on structural, mechanical and anisotropic properties are very important for superhard materials due to their widespread industrial applications. Here, a comprehensive analysis of the structural, mechanical and anisotropic behavior of three BC8N phases (denoted as BC8N-1, BC8N-2, and BC8N-3) under pressure are present by first principles calculations. Initially, the optimized structural parameters are consistent with the available theoretical results. Furthermore, it is found that the three phases of BC8N are structural stability under pressure. The elastic constants show an increasing tendency, and keep mechanically stable within the considered pressure. From the calculated B/G and Poisson’s ratio, it is predicted that the three phases of BC8N are brittle materials at low pressure, but strongly prone to ductility when the pressure is above 257.5, 254 and 259.5 GPa, respectively. The calculated hardness suggests that all three phases of BC8N belong to superhard materials, the order of hardness from high to low is BC8N-3 >BC8N-1 >BC8N-2. However, the hardness of BC8N-1 and BC8N-2 are less than 40 GPa when the pressure increasing to 315.4 and 329.1 GPa, respectively, which indicated that they no longer belong to the class of superhard materials. Finally, the pressure-induced anisotropic behavior has been also analyzed. It will provide a more comprehensive understanding for B-C-N compounds.

The plane Poiseuille flow of a Bingham plastic with pressure-dependent material parameters is analysed. Both the plastic viscosity and the yield stress are assumed to vary linearly with pressure and analytical solutions are derived for the two-dimensional pressure and the one-dimensional velocity. The effects of the plastic-viscosity and yield-stress growth parameters on the thickness of the unyielded plug and the conditions for the occurrence of flow are discussed.

A micro-mechanical composite material model is developed to simulate the behavior of unidirectional composites under impact loading conditions in the nonlinear finite element solver (LS-DYNA®). The nonlinear strain rate and pressure dependency in the composite material model is accounted by the resin, which uses previously developed state variable viscoplastic equations. These equations have been originally developed for metals; however, these are modified to account for the significant contributions of hydrostatic stresses typically observed in polymers. The material model also uses a continuum damage mechanics (CDM) based failure model to incorporate the progressive post-failure behavior. A set of Weibull distribution functions are used to quantify this behavior, and a methodology of assigning physical significance to the choice of damage/softening parameters used in these functions is presented. The impact response of composite laminate plates has been simulated and compared to the experiments. It has been observed that the predicted results compare favorably to the experiments.

The pressure-dependent Raman spectra of synthetic alforsite, Ba5(PO4)3Cl, were investigated up to 34.9 GPa using a DAC at room temperature. During compression to greater than 20 GPa, new Raman active peaks of Ba5(PO4)3Cl were observed. The Raman frequencies of all observed bands for Ba5(PO4)3Cl alforsite increase continuously with increasing pressure. The quantitative analysis of PO4 internal vibrational pressure dependences for different Raman bands in alforsite shows that the ν3 anti-symmetric stretching modes have larger pressure coefficients (from 4.24 to 5.46 cm−1/GPa) whereas, the ν4 anti-symmetric bending vibrations have smaller pressure coefficients (from 1.16 to 2.04 cm−1/GPa). The external modes show larger pressure coefficients (from 4.71 to 5.54 cm−1/GPa). The PO4 internal modes in Ba5(PO4)3Cl alforsite give isothermal mode Gruneisen parameters varying from 0.147 to 0.488, which yields an average PO4 internal mode Gruneisen parameter of 0.314. On the other hand, the external modes give isothermal mode Gruneisen parameters from 1.583 to 2.030. The external modes mainly contribute to the bulk Gruneisen parameter since the bulk thermochemical Gruneisen parameter was determined as 1.44.

The density and viscosity of propylene glycol have been simultaneously measured over the temperature range from (298–452) K and at pressures up to 245 MPa using a combined method of hydrostatic weighing and falling-body techniques, respectively. The combined expanded uncertainty of the density, pressure, temperature, and viscosity measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be (0.15–0.30) %, 0.05%, 0.02 K, and (1.5–2.0) %, respectively. The measured high-temperature and high-pressure PVT data for propylene glycol were used to develop theoretically based Tait-type equation of state (EOS). The measured viscosities were used to develop theoretically based viscosity correlation models (Arrhenius-Andrade and VFT type models) with the pressure dependent parameters.

In this work, the replication-based microcontact printing method has been presented to study the deformation effect of different printing times and printing pressures on the microcontact printed structures. Cost-effective microcontact printing channels of self-assembled monolayers of alkanethiol have been prepared on gold surface. The alkanethiol inking the polydimethylsiloxanes stamp effectively forms the self-assembled monolayers on the noble gold surface that protects the metal against etchant solution and thereby forms channel-like structures. To address the deformation issue, variations in the printing time in the range of 30 s–60 min and the printing pressure ranging from 840 to 4200 Pa have been studied. The estimation of differing the channel width and channel space with varying printing time and pressure shows the best resolution structures printed under minimal printing time at atmospheric pressure.

A triaxiality-dependent Cohesive Zone Model for the numerical prediction of failure loads of notched specimens under different loading modes is presented. Since the cohesive crack is modeled by means of the embedded crack approach , one can express the cohesive parameters with variables from the continuum, such as pressure or triaxiality. The model is validated by its application to two experimental campaigns previously developed by the authors on notched specimens subjected to mode I and III loadings respectively, made of gray cast iron, a strongly pressure dependent material.

A theoretical investigations on the structural stability and mechanical properties of Be3N2 crystallising in α and β phases was performed using first-principles calculations based on density functional theory. The obtained ground state structure and mechanical properties are in excellent agreement with the available experimental and theoretical data. A full elastic tensor and crystal anisotropy of Be3N2 in two phases are determined in the wide pressure range. Results indicated that the two phases of Be3N2 are mechanically stable and strongly pressure dependent in the range of pressure from 0 to 80 GPa. The superior mechanical properties show that the two phases of Be3N2 are potential candidate structures to be the hard material. And the α-Be3N2 has better mechanical properties than β-Be3N2. By the calculated B/G ratio, it is predicted that both phases are intrinsically brittleness and strongly prone to ductility when the pressure is above 65.6 and 68.5 GPa, respectively. Additionally, the pressure...

Cerebrovascular CO2 reactivity is affected by nitric oxide (NO). We tested the hypothesis that sildenafil selectively potentiates NO-cGMP signaling, which affects CO2 reactivity. Fourteen healthy males (34 ± 2 yr) were enrolled in the study. Blood pressure (BP), ECG, velocity of cerebral blood flow (CBF; measured by transcranial Doppler), and end-tidal CO2 (EtCO2) were assessed at baseline (CO2 ~39 mmHg), during hyperventilation (CO2 ~24 mmHg), during hypercapnia (CO2 ~46 mmHg), during boluses of phenylephrine (25–200 µg), and during graded head-up tilting (HUT). Measurements were repeated 1 h after 100 mg sildenafil were taken. Results showed that sildenafil did not affect resting BP, heart rate, CBF peak and mean velocities, estimated regional cerebrovascular resistance (eCVR; mean BP/mean CBF), breath/min, and EtCO2: 117 ± 2/67 ± 3 mmHg, 69 ± 3 beats/min, 84 ± 5 and 57 ± 4 cm/s, 1.56 ± 0.1 mmHg·cm−1·s−1, 14 ± 0.5 breaths/min, and 39 ± 0.9 mmHg, respectively. Sildenafil increased and decreased the hypercapnia induced in CBF and eCVR, respectively. Sildenafil also attenuated the decrease in peak velocity of CBF, 25 ± 2 vs. 20 ± 2% ( P < 0.05) and increased the eCVR, 2.5 ± 0.2 vs. 2 ± 0.2% ( P < 0.03) during hyperventilation. Sildenafil did not affect CBF despite significant increases in the eCVRs that were elicited by phenylephrine and HUT. This investigation suggests that sildenafil, which potentiates the NO-cGMP signaling, seems to affect the cerebrovascular CO2 reactivity without affecting the static and dynamic pressure-dependent mechanisms of cerebrovascular autoregulation.

In this paper, we present a flash photography method for the measurements of the fluid flow dynamic of a fluid dispensing system. A fluid dispensing system is one of the key processes to deliver fluid materials to various positions in assembly parts of several manufacturing industries. A dispensing process is a complicated dynamic process and time-dependent. The parameter identification of a fluid dispensing model by using with measurement values of the accumulated final volume is usually employed. This technique may not provide the satisfactory results. To improve the accuracy of the parameter identification, the fluid flow measurements based on the flash photography methods is proposed. The experiments with various fluid levels inside a syringe were carried out to evaluate the performance of the proposed system. The pressure dependent fluid flow rate curve constructed from the measurement values is presented, to identify the parameters associated with the model. The measured parameters are consistent with the fluid properties reported in the literature.