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In this paper, electronic and structural properties such as lattice constant, energy band structure, and density of states of InP in bulk and nanowire are calculated. The calculations have been performed using the Pseudopotential method in the framework of density functional theory (DFT) with local density approximation (LDA), and generalized gradient approximation (GGA) by Quantum Espresso package. The results show a direct bandgap of 1.4 eV at the Γ point in the Brillouin zone and have not cut the Fermi level, with a good agreement with the available experimental results. Also, band structure in nanowires of about 1.49 eV was calculated, which shows an increased bulk state. The calculated results show good agreement with the available experimental results.

As a key component of electronic skins, flexible pressure sensors have attracted more and more attention because of the increasingly growing demand. Stability is a key parameter to evaluate pressure sensors, while relatively few reports have focused on it. Here, a paper-based piezoresistive sensor is developed, in which, the airlaid paper based sensing layer is modified with silver nanowires (AgNWs) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and sandwiched in between two convex electrodes. Due to the cross bonding of PEDOT:PSS membrane, the conductive paths of AgNWs networks are strengthened and stabilized, thus the stability of the sensor is found to be significantly improved. Besides, to regulate the compressibility by varying sensing layers, the performance of the proposed sensor can be further improved, and its practical application performances in healthcare pulse monitoring, tiny muscle motion, and voice recognition are demonstrated. The results confirm that PEDOT:PSS has the potential as stabilization media to AgNWs for paper-based flexible wearable electronics. [ABSTRACT FROM AUTHOR]

The dewatering of large amount of industry sludge is one of the significant environmental problems in the pulp and paper industry. Calcium carbonate fillers are an important component in primary sludge from paper mills. In this paper, the role of precipitated calcium carbonate (PCC) on the dewaterability of simulated mixed paper mill sludge (the mixture of PCC and secondary sludge) without and with FeCl 3 conditioning was studied. The results showed that when the PCC content increased from 0 to 600 mg/g dry sludge (DS) without FeCl 3 conditioning, the moisture content (MC) and the specific resistance to filtration (SRF) decreased from 89.4% and 3.1 × 1013 m/kg to 66.7% and 2.4 × 1012 m/kg, respectively. However, when the PCC content was high enough (> 444 mg/g DS), the effective moisture content (MC*) changed little and the net sludge solid yield (Y N) decreased, indicating that the non-conditioning effect of PCC dominated at high PCC content. Furthermore, increasing PCC content reduced the compressibility coefficient, although the change was insignificant from 1.06 to 0.91. When FeCl 3 was used as the chemical conditioner, FeCl 3 and PCC had additive effects on improving the sludge dewaterability (such as MC, SRF and compressibility). The improving mechanism of PCC on the sludge dewaterability can be explained by the release of Ca2+ from PCC caused by lower pH, the bridging effect of multivalent cation and the formation of more rigid sludge flocs. [Display omitted] ● PCC existed in sludge improve its filterability and compressibility. ● PCC component hardly affected the effective moisture content at high PCC content. ● PCC can improve the sludge dewaterability with the synergistic assistance of FeCl 3. [ABSTRACT FROM AUTHOR]

Smoothness of paper surface is an important property of paper from its printability viewpoint. A number of techniques are available for characterizing the topographical features of paper surface. These techniques have led to the development of smoothness testers of various types such as air-leak testers, optical contact testers, surface profilers, and a number of ink and liquid application apparatus to assess the smoothness. While all these methods are intended to serve the same purpose, they differ so greatly in their basic approach that the agreement between them cannot be taken for granted. In the present work, these methods have been applied to characterize the surface of handsheets of mechanical pulps. A comparison of these methods reveals that different methods grade these pulps differently confirming the multidimensional nature of the surface structure

ABSTRACT: We reformulate the original model of Hatchell and Bourne and Røste, Stovas and Landrø that couples fractional velocity change to subsurface strain via a fundamental constant R. The new model combines elastic compressibility of a dual‐porosity system for a sand–shale mixture with horizontal planes of inter‐granular weakness. The majority of observed R‐factor magnitudes from post‐stack 4D seismic data in both the reservoir and overburden can thus be explained. R is predicted to depend strongly on lithology and also initial strain state. The model is also extended to predict the observed angle‐dependence of time‐lapse time‐shifts from pre‐stack data. An expression for the gradient of time‐shift with incidence angle is obtained in terms of the background VP/VS, and also the ratio of tangential to normal compliances BT/BN representing loss or creation of inter‐granular coupling. If accurately estimated from data, this compliance ratio can be used as an additional parameter to assess the post‐production state of the overburden. It is concluded that whilst R remains the over‐arching parameter controlling the magnitude of time‐shifts measured from 4D seismic data, BT/BN is a subtler parameter that may also prove of future value. [ABSTRACT FROM AUTHOR]

Highlights: [•] A dynamic model for longitudinal vibration assisted guillotining of paper is developed. [•] Empirical model of a stack of thin paper material is identified. [•] Novel measurement procedure for determining dynamic behavior for ultrasonic assisted cutting is developed. [•] Simulated cutting forces are in agreement with the experimentally recorded cutting forces. [Copyright &y& Elsevier]

The excess isentropic compressibilities of binary mixtures of 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide with ethyl acetate or methanol and 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide with dimethyl sulfoxide or methanol were calculated based on thermodynamically rigorous ideal mixing rule. For the discussed mixtures, great differences between excess values of isentropic compressibilities and isentropic compressibility deviations from a simple mole fraction average of pure components isentropic compressibilities are observed. The usability and correctness of the Prigogine-Flory-Patterson (PFP) model for mixtures under test is discussed as well, because in constructing the PFP theory, hydrogen bonds and interactions of strong electrostatic nature are excluded [Fluid Phase Equilib. 233 (2005) 157]. [ABSTRACT FROM AUTHOR]

Hypo sludge, a waste product from paper industries, has had very few known uses and is usually only disposed of in landfills after the production process. On the other hand, inferior grade soils are being treated with commercial additives to improve their characteristics, some of which in return cause harm to the environment in their production. Hypo sludge possesses roughly identical elements found in that of commercial additives which highlight its potential of being a viable substitute to the latter. The study focused on the vertical strain and compressive property of soils; and 6 design mixes were formulated: 100% soil; 5% hypo sludge - 95% soil; 10% hypo sludge - 90% soil; 15% hypo sludge - 85% soil; 20% hypo sludge - 80% soil; 5% lime - 95% soil. Oedometer tests were conducted to analyze the behavior of the soil when cured with the additive. Results from tests concluded that the 10% hypo sludge and 90% soil mix was the optimum mix ratio to produce the greatest positive change in both parameters considered among the other hypo sludge mixes. An empirical model was also developed which determines the vertical strain of a soil sample given an applied vertical load and percentage of hypo sludge added. Moreover, the mix performed just slightly inferior to the commercial additive, lime, therefore proving that hypo sludge is at par to that of the typical soil additive. As a result, a purpose for this waste material has been discovered. [ABSTRACT FROM AUTHOR]

Abstract: Solar-power based sorption refrigeration systems do not suffer from the problem of greenhouse gas emission and release of ozone layer depleting substances as in the case of conventional vapour compression refrigeration system. Absorption based systems are already commercially available while adsorption based systems are still in research and development stage. Progress and development of solar-powered adsorption cooling systems have been described in this paper. Factors preventing commercialization of this system have been discussed in detail. The state of the ongoing research, to make the system more efficient and cost effective, has been presented. [Copyright &y& Elsevier]

The past 130+ years of research into the production of corrugated packaging has produced a tremendous wealth of information about the structural dynamics of corrugated boxes in use and in failure. Most of the studies in this area were published in the journals of the paper industry. However, much of the current work on corrugated fiberboard packaging now comes from individuals with a focus on corrugated packaging as a whole rather than on the corrugated paper or structures that comprise the packaging material. Because of the difficulty in accessing or identifying some of the previous art, more recent studies may tread ground well covered by others decades earlier. This review focuses on the process of box compression and the utility of box compression testing, bringing previous work back to the fore to provide useful background for current studies. It examines the conditioning and testing process in detail, discusses the state of the art in compression estimation, and explores various parameters that affect box compression strength that are not captured in most current industry models. It also looks at how box compression results are related to field performance of boxes in unit loads. In the process, it identifies many areas for fruitful new research. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Previously, studies have recognized that the characterization of the compression behavior of sand–silt mixtures that use different void ratio concepts is controversial and incomplete, because most of the earlier studies considered the global or intergranular void ratio as reliable parameters to explain the differences between the mechanical responses of sand–silt mixtures. However, the equivalent void ratio concept could be used as a well-founded alternative to express the compression behavior in mixed soils. To achieve this goal, compression behavior tests on Chlef silty sand were carried out. The specimens were subjected to one-dimensional (1D) oedometer loading conditions that emphasized the application of the global, intergranular and equivalent void ratios concepts. The Chlef sand specimens that were mixed with 0% to 40% silt contents were prepared using two fabric techniques [dry funnel pluviation (DFP) and moist tamping (MT)] at three initial relative densities (Dr = 18%, 52%, and 88%). A detailed analysis was carried out to compare the normal compression characteristics with those that were derived from the intrinsic compression (the normalized compression curves). Based on experimental evidence, this paper introduces a new dependable parameter, the equivalent compression index (Cc∗) , which could be obtained from the [ e∗–(log⁡σv′) ] curve. The test results reveal that the equivalent void ratio concept plays a reliable role in the prediction of the compression behavior of the Chlef sand–silt mixtures, where the compressibility parameters of the tested specimens are well normalized using the equivalent compressibility curves for different fines contents that consider both fabric techniques and all selected initial relative densities. Based on the test results, the intrinsic compression characteristics (Ccint,Cc−gint,andCc∗int) exhibit very similar tendencies compared to those of the normal compression (Cc,Cc−g,andCc∗) and a correlation has been suggested between the two different compression characteristics. In addition, a new relationship has been developed that expresses the undrained mechanical characteristics (taken from a previous study) as a function of the obtained compression indexes that consider the effects of all selected parameters under the same experimental conditions. [ABSTRACT FROM AUTHOR]

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In this paper, we introduce a few notions of inverse topological pressure $({\tilde P}^-, P^-, P_- )$, defined in terms of backward orbits (prehistories) instead of forward orbits. This inverse topological pressure has some properties similar to the regular (forward) pressure but, in general, if the map is not a homeomorphism, they do not coincide. In fact, there are several ways to define inverse topological pressure; for instance, we show that the Bowen type definition coincides with the one using spanning sets. Then we consider the case of a holomorphic map $f:{\mathbb P}^2 {\mathbb C}\to {\mathbb P}^2 {\mathbb C}$ which is Axiom A and such that its critical set does not intersect a particular basic set of saddle type Λ. We will prove that, under a technical condition, the Hausdorff dimension of the intersection between the local stable manifold and the basic set is equal to ts, i.e. $HD (W^s_\delta (x)\cap \Lambda)=t^s$, for all points x belonging to Λ. Here ts represents the unique zero of the function t→P-(tϕs), with P- denoting the inverse topological pressure and $\phi^s(y):=\log|Df|_{E_y^s}$, y∈Λ. In general, $HD (W^s_\delta (x)\cap\Lambda)$ will be estimated above by ts and below by $t^s_-$, where $t^s_-$ is the unique zero of the map t→P_(tϕs). As a corollary we obtain that, if the stable dimension is non-zero, then Λ must be a non-Jordan curve, and also, if f|Λ happens to be a homeomorphism (like in the examples from [13]), then the stable dimension cannot be zero. [ABSTRACT FROM AUTHOR]

The influence of pressure on the optical properties of nanostructured tetragonal Cu 2 Sb has been investigated jointly by experimental Raman spectroscopy (RS) and theoretical first-principles calculation based on density functional theory (DFT) varying pressure from zero (ambient condition) to 45 GPa. The DFT determined pressure dependence of the Raman active modes and the mode-Grüneisen parameters for each Raman mode are found to be in excellent agreement with those experimentally determined. Comparison of the pressure evolution of the experimental Raman data with those of DFT has allowed us to make the proper assignment of optical phonon modes. Image 1 • The Raman modes of the Cu 2 Sb were observed under high-pressures conditions. • The high-pressure in-situ data were supported by ab initio calculations. • The compressibility parameter of the Cu2Sb were obtained. • In-situ high-pressure Raman scattering and ab-initio studies in Cu2Sb up to 45 GPa. [ABSTRACT FROM AUTHOR]

Compressibility of liquid flame spray-deposited porous TiO 2 nanoparticle coating was studied on paperboard samples using a traditional calendering technique in which the paperboard is compressed between a metal and polymer roll. Surface superhydrophobicity is lost due to a smoothening effect when the number of successive calendering cycles is increased. Field emission scanning electron microscope surface and cross‒sectional images support the atomic force microscope roughness analysis that shows a significant compressibility of the deposited TiO 2 nanoparticle coating with decrease in the surface roughness and nanoscale porosity under external pressure. PACS: 61.46.-w; 68.08.Bc; 81.07.-b [ABSTRACT FROM AUTHOR]

Addressing the challenges of wet and soft loess foundations is crucial in geotechnical engineering due to their inherent low strength and high compressibility. High-temperature sintering technology is a leading method for enhancing loess foundations, known for its fast processing and effective reinforcement. This paper focuses on the effects of saturation on the compressibility of sintered loess, using results from saturation and compression tests. It highlights how saturation influences loess differently under various sintering conditions. Particularly, loess sintered at 200°C breaks down after saturation, losing its resistance to deformation. By contrast, loess sintered at other conditions retains some deformative resistance, but its compressibility still increases. The study finds an inverse relation between sintering temperature and the increase in compressibility after saturation. Additionally, it examines changes in compressibility indices, which include the compression coefficient, compression index, and modulus of compressibility. These are analyzed based on different saturation times, establishing a law that links saturation time to the compressibility of sintered loess. [ABSTRACT FROM AUTHOR]

An inducer is a key component in a cryogenic pump to improve its cavitation performance. The thermodynamic effects of the cryogenic medium make the cryogenic cavitation flow extremely complicated. For this reason, it is crucial to investigate the cryogenic cavitation flow of the inducer which is equipped upstream of the cryogenic pump. In this paper, the isothermal cavitation model is modified based on the law of heat conduction, and the cryogenic cavitation model of the inducer is developed by considering thermodynamic effects. The turbulence model is also modified to account for the compressibility of cryogenic cavitation flow. The methods of numerical calculations are performed to investigate the influence of thermodynamic effects on cryogenic cavitation of the inducer. The law of the spatio-temporal evolution of cryogen cavitation in the inducer is clarified. The initial position, development and collapse phenomenon of cavitation are obtained. The relationship between the generation and collapse of the cavitation and the work capacity of the inducer's blade, the relationship between thermodynamic effects and the influence of the inducer's blade tip leakage vortex and thermodynamic on cryogenic cavitation of the inducer are revealed. [ABSTRACT FROM AUTHOR]

Low damping characteristics have always been a key sticking points in the development of gas bearings. The application of squeeze film dampers can significantly improve the damping performance of gas lubricated bearings. This paper proposed a novel hermetic diaphragm squeeze film damper (HDSFD) for oil-free turbomachinery supported by gas lubricated bearings. Several types of HDSFDs with symmetrical structure were proposed for good damping performance. By considering the compressibility of the damper fluid, based on hydraulic fluid mechanics theory, a dynamic model of HDSFDs under medium is proposed, which successfully reflects the frequency dependence of force coefficients. Based on the dynamic model, the effects of damper fluid viscosity, bulk modulus of damper fluid, thickness of damper fluid film and plunger thickness on the dynamic stiffness and damping of HDSFDs were analyzed. An experimental test rig was assembled and series of experimental studies on HDSFDs were conducted. The damper fluid transverse flow is added to the existing HDSFD concept, which aims to make the dynamic force coefficients independent of frequency. Although the force coefficient is still frequency dependent, the damping coefficient at high frequency excitation with damper fluid supply twice as that without damper fluid supply. The results serve as a benchmark for the calibration of analytical tools under development. [ABSTRACT FROM AUTHOR]

Fine-grained soils containing diatom microfossils of biological origin are found worldwide. However, although these soils are acknowledged to have unique physical and mechanical properties, the exact role of diatoms in determining their compression and hydraulic behaviours remains unclear, especially when high effective stress is involved, and the underlying micromechanism is yet to be revealed. This study investigated the compression and permeability of diatomaceous soils prepared by mixing pure diatom and kaolin powders through one-dimensional constant rate of strain compression tests with a maximum vertical stress of 10 MPa. The microstructure of the soils studied was observed by atomic force microscopy, scanning electron microscopy and mercury intrusion porosimetry, and the microstructural evolution during compression was traced. The results indicate that the special hollow structure of diatom particles with internal pores contributes significantly to the high void ratio, compressibility and permeability of diatomaceous soils, and increasing the diatom content improves the pore distribution non-uniformity of the diatom–kaolin mixtures. In addition, the diatom particles have high brittleness and breakage potential, leading to microstructural rearrangement during compression, especially pore-structure adjustment. Lower compressive stress deforms the inter- and intra-aggregate pores, but higher vertical stress damages the diatoms' hollow structure, which changes the compression and hydraulic parameters in a different manner from the case of conventional clay. This paper enriches the knowledge concerning the multilevel behaviour of fine-grained soils containing diatom microfossils and provides a fundamental dataset. [ABSTRACT FROM AUTHOR]

A numerical method is used to solve the thermal analysis of natural convection in enclosures. This paper proposes the use of an implicit artificial-compressibility model in conjunction with the Radial Point Interpolation Meshless (RPIM) method to mimic laminar natural convective heat transport. The technique couples the pressure with the velocity components using an artificial compressibility model. The RPIM is used to discretize the spatial terms of the governing equation. We solve the semi-algebraic system implicitly in backward Euler pseudo-time. The proposed method solves two test problems—natural convection in the annulus of concentric circular cylinders and trapezoidal cavity. Additionally, the results are validated using experimental and numerical data available in the literature. Excellent agreement was seen between the numerical results acquired with the suggested method and those obtained through the standard techniques found in the literature. [ABSTRACT FROM AUTHOR]

A numerical model for the simulation of the performance of an oscillating water column (OWC) subjected to non-breaking and breaking waves is proposed in this paper. The numerical model consists of a hydrodynamic model specifically designed to simulate breaking waves and a pneumatic model that takes into account the air compressibility. The proposed numerical model was applied to evaluate the potential mean annual energy production from the waves of two coastal sites characterized by different hydrodynamic conditions: a deep-water condition, where the OWC interacts with non-breaking waves, and a shallow-water condition, where the OWC is subjected to breaking waves. The numerical results show that the effects of the air compressibility can be considered negligible only in numerical simulations of the performances of reduced-scale OWC devices, such as those used in laboratory experiments. We demonstrated that in real-scale simulations, the effect of the air compressibility within the OWC chamber significantly reduces its ability to extract energy from waves. The numerical results show that the effect of the air compressibility is even more significant in the case of a real-scale OWC located in the surf zone, where it interacts with breaking waves. [ABSTRACT FROM AUTHOR]

This paper is a summary of many of the key findings on the application of geosynthetics in tailings storage facilities. Topics include the compressibility and permeability of tailings, the equations predicting leakage through circular and non-circular geomembrane holes, the effect of the subgrade permeability, and the effect of a lateral drainage system within tailings on leakage predictions. Two commonly encountered engineering problems relating to the piping through circular geomembrane holes and the opening width of non-circular defective geomembrane seams are given to demonstrate the potential application of leakage prediction equations. Meanwhile, issues related to the subgrade imperfection and the long-term performance of both high-density polyethylene (HDPE) and bituminous geomembranes in tailings storage applications are addressed. The research highlights that an appropriate HDPE geomembrane liner can be expected to perform very well for an extremely long time, limiting leakage and contaminant migration from the facility into the surrounding environment if the liner is well constructed on a suitable subgrade. [ABSTRACT FROM AUTHOR]

The impact of climate change has become increasingly severe in forests, where droughts and strong winds on the one hand and extreme rainfall events on the other hand can damage forest ecosystems. To mitigate the effects of drought and enhance soil water retention capacity, three types of soil conditioners (SCs), labeled SC_R, SC_CG, and SC_ZZC, were developed as part of the European project ONEforest. All the conditioners are based on Xanthan gum and have different types and amounts of fillers with diverse cellulose fiber lengths. These can offer the potential to optimize the SC characteristics, e.g., water absorption, water retention, and mechanical stability. This paper focuses on the influence of fillers in the SCs on the geotechnical properties of forest soils from Ljubelj in the Alpine part of Slovenia (S1), Catalonia, northeastern Spain (S2), and Heldburg, Germany (S3). The results show an increase of 53% to 100% in the water absorption of treated soil. A less favorable impact of the SCs was found on the drained shear strength and the compressibility. The drained shear strength of untreated forest soils in a saturated state was S1 c′ = 4.4 kPa, φ′ = 33.5°; S2 c′ = 1.4 kPa, φ′ = 30.0°; and S3 c′ = 12 kPa, φ′ = 28.0°. The addition of SCs results in a reduction in the drained shear strength of saturated mixtures. The reduction depends on the dosage of added SC—whether it is a low (L) or a high (H) dosage. For instance, when the soil S1 was treated with a low dosage of the soil conditioner SC_R, it demonstrated a cohesion (c′) of 11 kPa and a friction angle (φ′) of 27.0°. However, increasing the dosage of the SC_R led to a decrease in both the cohesion and the friction angle for the same soil (c′ = 7.7 kPa, φ′ = 25.0°). Additionally, the type of soil conditioner also impacts the drained shear strength. Among the mixtures with a high dosage of the SC_R, SC_CG, or SC_ZZC, those containing the SC_CG with the longest fibers stand out, demonstrating the highest friction angle. Therefore, longer fibers can be a promising component of the SCs to reduce the negative influence of XG on the mechanical properties of treated soils. [ABSTRACT FROM AUTHOR]

The uniqueness of entropy solution for the compressible Euler equations is a fundamental and challenging problem. In this paper, the uniqueness of a composite wave of shock and rarefaction of one-dimensional compressible Euler equations is proved in the inviscid limit of compressible Navier--Stokes equations. Moreover, the relative entropy around the original Riemann solution consisting of shock and rarefaction under the large perturbation is shown to be uniformly bounded by the framework developed in [M. J. Kang and A. F. Vasseur, Invent. Math., 224 (2021), pp. 55--146]. The proof contains two new ingredients: (1) a cut-off technique and the expanding property of rarefaction are used to overcome the errors generated by the viscosity related to inviscid rarefaction; (2) the error terms concerning the interactions between shock and rarefaction are controlled by the compressibility of shock, the decay of derivative of rarefaction, and the separation of shock and rarefaction as time increases. [ABSTRACT FROM AUTHOR]

In this paper, we investigated Caputo fractional integro-differential equations with noninstantaneous impulses and nonlocal conditions. By employing the solution operator, the Mönch fixed point theorem, and the stepwise estimation method, we eliminated the Lipschitz condition of the nonlinear term, while also dispensing with the requirement for the compressibility coefficient condition 0 < k < 1. The main results presented represented a generalization and enhancement of previous findings. Furthermore, an example was provided to verify the application of our main results. [ABSTRACT FROM AUTHOR]

Fiber-reinforced elastomeric isolators (FREIs) have been proposed as a cost-effective solution for expanding the use of seismic isolation to normal-importance structures. By using lightweight fiber reinforcement and eliminating the attachment plates, FREIs reduce cost while improving the isolation efficiency and reducing tensile stresses in the rubber. However, the flexural flexibility of the fiber allows cross-sectional distortions (i.e., warping) to occur, which significantly impacts the stability of these devices. This paper evaluates the buckling of rectangular, circular, and annular FREIs, taking into account shear warping effects. A planar buckling theory previously proposed by the authors is adapted for the three-dimensional problem, and effective warping rigidities and warping-related areas are derived for the above bearing geometries, accounting for rubber compressibility. To assess the adequacy of the proposed buckling theory and derived warping properties in predicting the buckling of FREIs, a parametric finite element study is conducted. The critical load predictions of the proposed analytical formulation are found to be in excellent agreement with those of the numerical simulations. It is shown that traditional estimations of the buckling load that neglect warping are significantly unconservative. Finally, design recommendations and resources are provided for practice-oriented applications. [ABSTRACT FROM AUTHOR]

The compaction of a fabric reinforcement in a Universal Testing Machine (UTM) allows to determine the achievable fiber volume fraction across a wide range of pressures, a valuable information for composite manufacturing. As seen in the first international compressibility benchmark, inaccuracies in the fabric stack thickness measurement, the approach to compliance correction and the non-parallelism between compaction plates resulted in highly inaccurate compression curves. In this paper, the different variability sources affecting indirect thickness methods, based on the machine displacement, and direct methods with laser sensors are presented and its impact on the accuracy is estimated. In conclusion, both thickness measurement methods produced similar results; however, the thickness measured by direct methods experienced more variability due to minor changes in the rig's displacement or the orientations between plates, combined with other sources of variability such as external interferences or vibrations from the compaction plate which led to variations in measurement precision throughout the tests. [ABSTRACT FROM AUTHOR]

Two recent lower bounds on the compressibility of repetitive sequences, δ ≤ γ , have received much attention. It has been shown that a length-n string S over an alphabet of size σ can be represented within the optimal O (δ log n log σ δ log n ) space, and further, that within that space one can find all the occ occurrences in S of any length-m pattern in time O (m log n + o c c log ϵ n) for any constant ϵ > 0 . Instead, the near-optimal search time O (m + (o c c + 1) log ϵ n) has been achieved only within O (γ log n γ) space. Both results are based on considerably different locally consistent parsing techniques. The question of whether the better search time could be supported within the δ -optimal space remained open. In this paper, we prove that both techniques can indeed be combined to obtain the best of both worlds: O (m + (o c c + 1) log ϵ n) search time within O (δ log n log σ δ log n ) space. Moreover, the number of occurrences can be computed in O (m + log 2 + ϵ n) time within O (δ log n log σ δ log n ) space. We also show that an extra sublogarithmic factor on top of this space enables optimal O (m + o c c) search time, whereas an extra logarithmic factor enables optimal O(m) counting time. [ABSTRACT FROM AUTHOR]

The process of separating stages is crucial for multistage rockets, directly influencing the success of the launch plan. Different separation timing methods alter the flow field structure within the interlevel zone at separation, influencing the separation of the two-stage rockets. This paper employs the SST k-ω turbulence model to investigate the structure of the flow field and its aerodynamic and motion characteristics under different nozzle baffle opening and separation times, taking into account variable properties, supersonic compressibility, and the upstream–downstream interference. First, we examined the standard flow field structure, considering the engine jet, the lateral jet between stages, and the disturbance from the external supersonic inflow. Then, we discussed the displacement characteristics and axial force coefficient curves of the first and second steps of the separation process. Finally, we explored the impact of baffle opening and separation times on the flow field structure and axial force coefficients of the two stages at the onset of separation. For the flow field structure, a delay in the baffle opening and separation moment led to a gradual increase in downstream and separation regions until they stabilized after a certain range. However, the axial force coefficients displayed different behavior before and after the design point. [ABSTRACT FROM AUTHOR]

In this study, we have simulated transient and steady state free convection flow and heat transfer inside a square enclosure filled with a copper-water nanofluid of spherical shape nanoparticles following Tiwari-Das model. The cavity containing an insulated rectangular obstacle of height ranging from 0% to 50% of the cavity side-length. The vertical sides of the enclosure are kept at different temperatures, while the flat sides are assumed to be adiabatic as the obstacle. The combined method of lines/penalty-artificial compressibility technique (MOL-PACT) has been applied to solve the dimensional time dependent mathematical model after converting it into a non-dimensional structure. The combined method of lines/penalty-artificial compressibility technique is recently successfully applied to simulate free convection of MHD fluid in square enclosure with a localized heating. The extension of this promising technique for studying heat transfer of nanofluids is one of the objectives of this paper. Another objective of the study is to inspect the impact of several model parameters such as, the obstacle height, nanoparticles volume-fraction, nanoparticles radius and Rayleigh number on streamlines, temperature distribution and Nusselt number as an expression of heat transfer inside the enclosure. The results have been discussed and shown graphically. Comparisons with former results for related cases in the literature are made and reasonably good agreements are observed. [ABSTRACT FROM AUTHOR]

Understanding the characteristics of arid surface soil deposits leads to increasing the confidence level before stabilizing and to applying such materials in the field. Two types of surface soil deposits in Kuwait, sabkha soil and dune sand, have been examined by series of intensive laboratory testing reported in this paper. The chemical, the physical, and the compressibility characteristics of the two soils have been examined and evaluated. A single oedometer test has been carried out in order to obtain the compressibility characteristics and the collapse behavior. This paper has concluded that the samples from sabkha soil have a lower initial void ratio than the samples from dune sands. The lower compressibility parameters values of surface soil deposits and slightly higher collapsibility values of sabkha soils are encouraging that surface soil deposits can be used for construction purposes after the suitable stabilizing technique. Despite their low compressibility, the stabilizing of arid soils should concentrate on reducing salts’ dissolution in these soils during saturation. [ABSTRACT FROM AUTHOR]

The object of this study is the wear resistance of marks for people with visual impairments, which are printed by the intaglio printing method on Ukrainian hryvnia banknotes to identify the banknote denominations. The subject of the study is to determine the impact of wear on the recognizability of marks for people with visual impairments and the identification of banknote denominations by people with visual impairments. The paper considers the problem of inadequate assessment of the level of banknote wear by the systems of control and rejection of protected products from the point of view of banknote accessibility for people with visual impairments. An improved methodology for determining the level of wear of the mark for people with visual impairments on Ukrainian hryvnia banknotes is given, taking into account the indicator of its accessibility for all population groups, in particular for people with absolute vision loss, throughout the entire period of circulation. According to the developed methodology, artificial wear of banknotes was carried out according to three test options. The results of changes in the mass of banknotes, the microstructure of the surface of banknotes, the compressibility of marks for people with visual impairments (elasticity level), and the level of tactile identification of the denomination of banknotes by people with total vision loss were obtained. It was determined that during the artificial wear of banknotes, the main destruction of the mark takes place in the first cycle. After the second cycle of wear, there is an increase in the elasticity of the mark for people with visual impairments, a decrease in the level of its tactile sensation and the identification of the denomination of the banknote. Therefore, the properties of banknotes after the second cycle of wear have been determined to be critical for withdrawing such banknotes from circulation. The revealed regularities make it possible to adjust the parameters of intaglio printing during the production of banknotes and to adjust the sorting equipment to determine the suitability of banknotes for further circulation, taking into account the criterion of accessibility of banknotes for all groups of people. [ABSTRACT FROM AUTHOR]

In this paper, we have analyzed behavior of the generalized compressible isotropic Blatz–Ko model and the so-called basic-Hencky model in the framework of a coupled axial-stretching to simple shear test under the plane stress condition. The mechanical behavior depends on both the stretching-direction, i.e. Θ and magnitude of displacement, i.e. γ prescribed on the sample edge. Based on, we have computed the transverse stretch versus longitudinal stretch. We have shown that, the approximate displacement field cannot be sustained in the context of BK-model. In contrast, results of FE-simulations show that, this deformation field can be maintained for appropriate value of Poisson's ratio and porosity parameter. Also, the Poisson's function was revisited in the context of BK-model and basic-Hencky model; a difference was highlighted. Besides, it turns out advantageous to use compressible isotropic logarithmic-strain-energy to model behavior of compressible isotropic rubber-like materials in the range of moderate strains. Some Finite Element simulations have been performed in order to validate our findings. [ABSTRACT FROM AUTHOR]

Soft clay is characterized by high compressibility, low permeability, low strength, and high water content, making it a poor substrate for construction. Hence, soil treatment is often required for soft clay. However, the traditional treatment methods, such as stacking and on-site mixing, involve large space, long time, and high cost. In contrast, lime is stable and cheap, but slow to set and harden. In this paper, the microbially induced carbonate precipitation (MICP) and lime composite curing of soft clay was investigated. Tests were carried out on soft clay samples with different lime ratios. By comparing the changes of strength, composition, and microstructure before and after curing, the mechanism of MICP/lime composite solidification of soft clay was systematically studied. The results showed that (1) a reasonable proportion of lime can react with water and CO2 in clay to generate CaCO3 , and also promote the induction of more CaCO3 precipitation by microorganisms, contributing to the improved strength of solidified clay; (2) MICP/lime composite curing can effectively reduce water in soft clay and help to improve the strength of solidified soil; (3) MICP and lime were complementary in terms of curing time, leading to continuous improvement of curing effect; and (4) the MICP/lime composite has a good effect on the solidification of soft clay. Under the experimental conditions in this study, the best solidification effect was observed for soft clay with a water content of 30% and a lime ratio of 30%. [ABSTRACT FROM AUTHOR]

This paper presents a coupled model that considers the nonlinear compressibility effect in fluid–structure interaction (FSI) during air-blast loading on flexible structures. In this coupled model, structural behaviour is idealized as a linear single-degree-of-freedom mass-spring-damper system whereas nonlinear fluid compressibility is considered by applying Rankine–Hugoniot jump conditions across a moving plate. The surrounding fluid medium is modelled with an ideal gas equation and hence, this model can be applied for FSI analysis with relatively strong shocks (reflection coefficient of up to 8). The nonlinear compressibility of the fluid medium at the backside of the plate is also considered in this coupled formulation and its effects on the structural responses are examined. Moreover, the negative/underpressure phase of the reflected wave profile, which is typically neglected in a decoupled model, is also considered in the proposed model and its influence on the structural response is also investigated. The study reveals that the nonlinear compressibility of fluid medium significantly influences the coupled FSI phenomena, especially in flexible lightweight structures. Numerical examples are presented to highlight the implications of the nonlinear compressibility effect in FSI on the reflected pressure profile and the response of flexible structures. Parametric dependencies of response on structural mass and natural frequency are examined thoroughly and a response spectrum is obtained. It is envisaged that the lightweight protective structure design under higher blast intensity may benefit from this study. [ABSTRACT FROM AUTHOR]

This paper presents a holistic view of the structural phase transitions in nanocrystals. The databases for size-induced phase transitions is a main part of this paper. The database on transitions with temperature contains 603 items on 415 crystals, and database on transitions under high pressure contains 209 items in 124 crystals. Moreover, some new aspects of such transitions are presented like island diagram and new analysis of anomalous compressibility observed in some nanocrystals. [ABSTRACT FROM AUTHOR]

This paper presents a theory for the buckling of short beams considering cross-sectional distortions due to transverse shear (i.e., shear warping), based on the consistent linearization of a geometrically nonlinear planar beam. The proposed deformation field considers the warping amplitude as an independent kinematic field, and the hyperelastic material assumes that the stresses normal and tangent to the deformed cross section are linear with respect to their work-conjugate finite strains. An approximate closed-form solution to the resulting quartic equation for the critical load is provided to facilitate practical implementation. Theoretical differences giving rise to distinct buckling theories for higher-order shear beams are discussed in terms of (1) the assumed deformation field, (2) variational consistency, and (3) material constitutive relation. The proposed formulation is applied to evaluate the stability of infinite strip unbonded fiber-reinforced elastomeric isolators (FREIs) with moderate-to-high shape factor, for which shear warping is expected to have a major influence due to the flexural flexibility of the fiber reinforcement. A homogenization procedure is described to obtain effective isolator rigidities considering rubber compressibility and fiber extensibility. Next, a finite element parametric study of the buckling of unbonded infinite strip FREIs is presented, and the results are used as a benchmark to evaluate the adequacy of the proposed and existing formulations. The theory presented herein and its approximate solution exhibit the best match with the numerical results, and the latter is deemed adequate for practical application. [ABSTRACT FROM AUTHOR]

The steady rise of deployable structures and mechanisms based on kirigami and origami principles has brought about design innovations that yield flexible and lightweight robots. These robots are designed based on desirable locomotion mechanisms and often incorporate additional materials to support their flexible structure to enable load-bearing applications and considerable efficient movement. One tetherless way to actuate these robots is via the use of magnets. This paper incorporates magnetic actuation and kirigami structures based on the lamina emergent mechanism (LEM). Three designs of magnetic-actuated LEMs (triangular prism, single LEM (SLEM), alternating mirror dual LEM (AMDLEM)) are proposed, and small permanent magnets are attached to the structures' flaps or legs that rotate in response to an Actuating Permanent Magnet (APM) to yield stick-slip locomotion, enabling the robots to waddle and crawl on a frictional surface. For preliminary characterization, we actuate the three designs at a frequency of 0.6 Hz. We observed the triangular prism, SLEM, and AMDLEM prototypes to achieve horizontal speeds of 4.3 mm/s, 10.7 mm/s, and 12.5 mm/s on flat surfaces, respectively. We further explore how changing different parameters (actuation frequency, friction, leg length, stiffness, compressibility) affects the locomotion of the different mechanisms. [ABSTRACT FROM AUTHOR]

This review paper aims to summarize recent advancements in time-marching schemes for solving Navier–Stokes (NS) equations in multiphase flow simulations. The focus is on dual-time stepping, local preconditioning, and artificial compressibility methods. These methods have proven to be effective in achieving high time accuracy in simulations, as well as converting the incompressible NS equations into a hyperbolic form that can be solved using compact schemes, thereby accelerating the solution convergence and allowing for the simulation of compressible flows at all Mach numbers. The literature on these methods continues to grow, providing a deeper understanding of the underlying physical processes and supporting technological advancements. This paper also highlights the imposition of dual-time stepping on both incompressible and compressible NS equations. This paper provides an updated overview of advanced methods for the CFD community to continue developing methods and select the most suitable two-phase flow solver for their respective applications. [ABSTRACT FROM AUTHOR]

This paper has proposed a new perspective of studying internal structure-based tests, the results of which will improve the present experimental methods and enrich our understanding of rock structure-based modeling without any core preparations, with low cost in a short time. Pore volume compressibility (PVC) is an important feature of rock and is related to mechanical and structural behavior of porous rock sample. An accurate evaluation of pore volume compressibility depends on experimental test which is time-consuming and costly. This paper outlines new method for evaluation of PVC of rock cores using a computed tomography (CT) scan-based finite element method (FEM). The verification studies were performed on a series of porous rock cores which were extracted from deep oil reservoirs in Iran. In order to construct a finite element model, a relationship between spatial elastic properties of samples and CT-scanned data images was derived. The samples were scanned by a conic beam computed tomography (CBCT) machine, and the scanned data were converted into a model to simulate PVC tests. The pore volumetric strains were obtained from a linear elastic analysis for each stress and pore pressure step. To validate the finite element analysis (FEA) results, a series of experimental PVC tests were conducted on the pre-scanned samples and PVC curves were extracted. As a result, the predictions calculated from the CT scan-based numerical models have shown a good correlation with the results obtained from laboratory experiments. The results revealed that it is possible to simulate PVC tests using this numerical proposed evaluation method in such a way that the cost and time of the tests were lowered. [ABSTRACT FROM AUTHOR]

25 years ago the June 1998 Focus Issue of "Chaos" described the proceedings of a workshop meeting held in Budapest and called "Chaos and Irreversibility", by the organizers, T. Tél, P. Gaspard, and G. Nicolis. These editors organized the meeting and the proceedings' issue. They emphasized the importance of fractal structures and Lyapunov instability to modelling nonequilibrium steady states. Several papers concerning maps were presented. Ronald Fox considered the entropy of the incompressible Baker Map B(x, y), shown here in Fig. 1. He found that the limiting probability density after many applications of the map is ambiguous, depending upon the way the limit is approached. Harald Posch and Bill Hoover considered a time-reversible version of a compressible Baker Map, with the compressibility modelling thermostatting. Now, 25 years later, we have uncovered a similar ambiguity, with the information dimension of the probability density giving one value from pointwise averaging and a different one with areawise averaging. Goldstein, Lebowitz, and Sinai appear to consider similar ambiguities. Tasaki, Gilbert, and Dorfman note that the Baker Map probability density is singular everywhere, though integrable over the fractal y coordinate. Breymann, Tél, and Vollmer considered the concatenation of Baker Maps into MultiBaker Maps, as a step toward measuring spatial transport with dynamical systems. The present authors have worked on Baker Maps ever since the 1997 Budapest meeting described in "Chaos". This paper provides a number of computational benchmark simulations of "Generalized Baker Maps" (where the compressibility of the Map is varied or "generalized") as described by Kumicák in 2005. [ABSTRACT FROM AUTHOR]

During the embossing process, a fiber sandwich is compressed between embossing tools. The use of ultrasound causes a short-term increase in the material temperature in addition to causing plastic deformation. The combination of the material compression and an increase in material temperature leads to structural changes, which can be observed by the change in mechanical properties of the cardboard. This work investigated the influence of an ultrasonically induced temperature increase on the structural changes of cardboard. Using three-parameter combinations, different temperature levels were achieved with a material densification of less than 5%. Subsequently, the samples were subjected to selected physical and visual analyses to characterize the change in the fiber structure. With the increase of 124 °C material temperature there was a decrease of about 15% in the splitting resistance and 10% in the bending stiffness. [ABSTRACT FROM AUTHOR]

Molecular simulation data of the vapour–liquid equilibria (VLE) published in the period 2005–2016 and listed in the Web-of-Science collection have been scrutinised and their correctness examined using the recently proposed exact compressibility factor criterion [I. Nezbeda, J. Chem. Eng. Data 61, 3964 (2016)]. It turns out that a large number of the examined data are very inaccurate, if not completely wrong, and this is illustrated by several examples. This problem goes, unfortunately, unnoticed and the data are further used by other researchers. The finding goes hand-in-hand with the becoming practice of ignoring the common etiquette of presenting (pseudo)experimental data, i.e. to provide sufficient information both on technical details and on data post-simulation processing which could enable anyone their independent check and further reliable use. Moreover, the problem of the correctness of published data does not concern only VLE data but any simulation results and these cases along with potential reasons are therefore also briefly discussed. An appeal is therefore made both to the community of simulators and users to examine data using available tools before publishing or using them. Similarly, an appeal is made also to reviewers to insist that the submitted papers with simulation data do contain all necessary details. [ABSTRACT FROM AUTHOR]

The effect of compressibility on supersonic corner flow is numerically investigated by the Reynolds-averaged Navier–Stokes equations with a full Reynolds stress model. A grid sensitivity analysis is conducted in this paper to ensure the reliability of our conclusions. Then, a parametric study by changing the Mach number in the range of M ∞ = 0.6 − 3.0 is carried out to investigate the effect of compressibility. The corner angle is also changed in the range of θ = 45 ° − 135 ° for each M ∞ to see the effect of the corner angle. As a result, the Mach number was found to have a negligible effect on the propagation of vortex cores in this study. However, it has a positive effect on both the friction coefficient and the total pressure loss. The geometrical transformation for the position of the vortex center proposed in our recent paper has been proved to be valid in over wide range. Moreover, we further find that a unified formula can describe the distribution of the total pressure loss under different Mach numbers and corner angles. In engineering terms, these laws will play an important role in the initial design and evaluation of the project with streamwise corners. [ABSTRACT FROM AUTHOR]

This paper discusses changes and developments in the field of Earth Structures that have been presented and discussed over the last fifty years at the annual national conferences on Foundation Engineering held (with foreign participation) in the city of Brno. [ABSTRACT FROM AUTHOR]

Marine clays possess poor engineering properties and need to be improved prior to any construction activities. Lime stabilisation is a widely adopted method of chemical stabilisation for such types of soils. This paper evaluates the effect of surcharge loads during curing of lime stabilisation of Cochin marine clays. In the case of lime-stabilised soil cured under surcharge loads, it is necessary to consider two processes – that is, cementation and consolidation—along which the structures of stabilised soils evolve. These two processes are interrelated and cannot be considered separately, especially in the early stages of curing when significant structural changes occur. This study investigated the strength and deformation characteristics of lime-stabilised Cochin marine clay subjected to surcharge loading during curing. The marine clay with 6% lime was subjected to surcharge loads of 20, 40 and 60 kPa for different curing periods up to 180 days. The effects of surcharge loading on shear strength and compressibility characteristics were evaluated at different curing periods. [ABSTRACT FROM AUTHOR]

The paper presents a method for calculating the thermodynamic parameters of refrigerant vapors during their compression in a scroll compressor. The method takes the properties of a refrigerant as a real gas into account, as well as the process of mixing two vapor portions inside the scroll unit when the full geometric degree of compression is reached. [ABSTRACT FROM AUTHOR]

The paper presents a review of the results that allowed us to find an exact analytical solution to the main problem of the turbulence theory consisting in a closed description of any moments and spectra of all random fields that are described by the Euler hydrodynamic equations for a compressible medium. This solution is based on an exact and explicit analytical solution to n-dimensional Euler equations in the limit of large Mach numbers (S. G. Chefranov, 1991). Based on the Dirac delta function theory, this solution gives an n-dimensional generalization of the well-known implicit Riemann (1860) solution to the one-dimensional Euler equations. In the one-dimensional case, the resulting solution exactly coincides with the explicit form of the Riemann solution for an arbitrary Mach numbers. We have obtained for the first time the exact value of the universal scaling exponent -2/3 for a spectrum of the turbulence energy dissipation rate corresponds to the exact analytical solution to fourth-order two-point moments of the velocity field gradient. We have noted a good agreement between this value and the observational data of turbulence intermittency in the surface atmosphere layer (M. Z. Kholmyansky, 1972) and with the findings of the well-known turbulence intermittency model by Novikov-Stewart (1964). [ABSTRACT FROM AUTHOR]