Rigid Media Research Articles

Radiation-Induced Transformations of an Isolated C6H6···HCN Complex: Possible Way to Synthesis of Interstellar Benzonitrile.

The recent detection of benzonitrile (C6H5CN) in the interstellar medium is one of the most fascinating discoveries in astrochemistry and molecular astrophysics. However, the mechanism of its formation in interstellar ices remains unclear. Here, we report the first evidence for the direct synthesis of benzonitrile through the radiation-induced transformations of an isolated C6H6···HCN complex in inert rigid media at cryogenic temperature (4.5 K), as monitored by Fourier transform infrared (FTIR) spectroscopy. The complex was prepared in a solid krypton matrix and characterized by the experimentally observed complexation-induced shifts in the FTIR spectra on the basis of comparison with the results of ab initio calculations. The formation of benzonitrile was revealed through the observation of its three fundamentals and partially confirmed by experiments with deuterated benzene. Presumably, C6H5CN results from the dehydrogenation of complex excited states followed by prompt radical-radical recombination within the matrix cage. The proposed route may be relevant to the formation of C6H5CN both in the bulky astrophysical ices and on the surface of interstellar dust grains.

Measuring audible acoustic frequencies parameters of rigid porous media via an innovative impedance tube method - Solving the inverse problem

This study introduces an experimental approach to measuring audible acoustic frequency parameters of a rigid porous medium using an impedance tube. Grounded in the equivalent fluid model, a derivative of Biot's theory, our investigation delves into the propagation of waves within porous media, emphasizing the importance of effective density and dynamic compressibility of the saturated fluid. Our primary focus is on resolving the inverse problem by minimizing both experimental and theoretical absorption coefficient expressions within the audible frequency range. Concurrently, we determine four pivotal parameters: viscous and thermal permeability, the inertia factor introduced by Norris, and the thermal tortuosity introduced by Lafarge. The outcomes include a comparative analysis between experimental and simulated absorption coefficients, leveraging optimized parameters, across two distinct polyurethane foam samples.

Effects of Contact Surface Shape on Dynamic Lifetime and Strength of Molecular Bond Clusters under Displacement- and Force-Controlled Loading Conditions.

Many experimental and theoretical studies have shown that the mechanical properties of cells and the extracellular matrix can significantly affect the lifetime and strength of the adhesion clusters of molecular bonds. However, there are few studies on how the shape of the contact surface affects the lifetime and strength of the adhesion clusters of molecular bonds, especially theoretical studies in this area. An idealized model of focal adhesion is adopted, in which two rigid media are bonded together by an array of receptor-ligand bonds modeled as Hookean springs on a complex surface topography, which is described by three parameters: the surface shape factor β, the length of a single identical surface shape L, and the amplitude of surface shapes w. In this study, systematic Monte Carlo simulations of this model are conducted to study the lifetime of the molecular bond cluster under linear incremental force loading and the strength of the molecular bond cluster under linear incremental displacement loading. We find that both small surface shape amplitudes and large surface shape factors will increase the lifetime and strength of the adhesion cluster, whereas the length of a single surface shape causes oscillations in the lifetime and strength of the cluster, and this oscillation amplitude is affected by the surface shape amplitude and the factor. At the same time, we also find that the pretension in the cluster will play a dominant role in the adhesion strength under large amplitudes and small factors of surface shapes. The physical mechanisms behind these phenomena are that the changes of the length of a single surface shape, the amplitude of surface shapes, and the surface shape factor cause the changes of stress concentration in the adhesion region, bond affinity, and the number of similar affinity bonds.

Phenylbenzothiazole-Based Platinum(II) and Diplatinum(II) and (III) Complexes with Pyrazolate Groups: Optical Properties and Photocatalysis.

Based on 2-phenylbenzothiazole (pbt) and 2-(4-dimethylaminophenyl)benzothiazole (Me2N-pbt), mononuclear [Pt(pbt)(R'2-pzH)2]PF6 (R'2-pzH = pzH 1a, 3,5-Me2pzH 1b, 3,5-iPr2pzH 1c) and diplatinum (PtII-PtII) [Pt(pbt)(μ-R'2pz)]2 (R'2-pz = pz 2a, 3,5-Me2pz 2b, 3,5-iPr2pz 2c) and [Pt(Me2N-pbt)(μ-pz)]2 (3a) complexes have been prepared. In the presence of sunlight, 2a and 3a evolve, in CHCl3 solution, to form the PtIII-PtIII complexes [Pt(R-pbt)(μ-pz)Cl]2 (R = H 4a, NMe2 5a). Experimental and computational studies reveal the negligible influence of the pyrazole or pyrazolate ligands on the optical properties of 1a-c and 2a,b, which exhibit a typical 3IL/3MLCT emission, whereas in 2c the emission has some 3MMLCT contribution. 3a displays unusual dual, fluorescence (1ILCT or 1MLCT/1LC), and phosphorescence (3ILCT) emissions depending on the excitation wavelength. The phosphorescence is lost in aerated solutions due to sensitization of 3O2 and formation of 1O2, whose determined quantum yield is also wavelength dependent. The phosphorescence can be reversibly photoinduced (365 nm, ∼ 15 min) in oxygenated THF and DMSO solutions. In 4a and 5a, the lowest electronic transitions (S1-S3) have mixed characters (LMMCT/LXCT/L'XCT 4a and LMMCT/LXCT/ILCT 5a) and they are weakly emissive in rigid media. The 1O2 generation property of complex 3a is successfully used for the photooxidation of p-bromothioanisol showing its potential application toward photocatalysis.

Electrohydrodynamic Couette–Poiseuille Flow Instability of Two Viscous Conducting and Dielectric Fluid Layers Streaming through Brinkman Porous Medium

The electrohydrodynamic plane Couette–Poiseuille flow instability of two superposed conducting and dielectric viscous incompressible fluids confined between two rigid horizontal planes under the action of a normal electric field and pressure gradient through Brinkman porous medium has been analytically investigated. The lower plane is stationary, while the upper one is moving with constant velocity. The details of the base state mathematical model and the linearized model equations for the perturbed state are introduced. Following the usual procedure of linear stability analysis for viscous fluids, we derived two non-dimensional modified Orr–Sommerfeld equations and obtained the associated boundary and interfacial conditions suitable for the problem. The eigenvalue problem has been solved using asymptotic analysis for wave numbers in the long-wavelength limit to obtain a very complicated novel dispersion relation for the wave velocity through lengthy calculations. The obtained dispersion equation has been solved using Mathematica software v12.1 to study graphically the effects of various parameters on the stability of the system. It is obvious from the figures that the system in the absence of a porous medium and/or electric field is more unstable than in their presence. It is found also that the velocity of the upper rigid boundary, medium permeability, and Reynolds number have dual roles on the stability on the system, stabilizing as well as destabilizing depending on the viscosity ratio value. The electric potential, dielectric constant and pressure gradient are found to have destabilizing influences on the system, while the porosity of the porous medium, density ratio and Froude number have stabilizing influences. A depth ratio of less than one has a dual role on the stability of the system, while it has a stabilizing influence for values greater than one. It is observed that the viscosity stratification brings about a stabilizing as well as a destabilizing effect on the flow system.

Cis/trans-[Pt(C∧N)(C≡CR)(CNBut)] Isomers: Synthesis, Photophysical, DFT Studies, and Chemosensory Behavior.

cis/trans Isomerism can be a crucial factor for photophysical properties. Here, we report the synthesis and optical properties of a series of trans- and cis-alkynyl/isocyanide cycloplatinated compounds [Pt(C∧N)(C≡CR)(CNBut)] [R = C6H4-4-OMe 1, 3-C4H3S 2; C∧N = 2-(2,4-difluorophenyl)pyridine (dfppy) (a), 4-(2-pyridyl)benzaldehyde (ppy-CHO) (b)]. The trans-forms do not isomerize thermally in MeCN solution to the cis forms, but upon photochemical irradiation in this medium at 298 K, a variable isomerization to the cis forms was observed. This behavior is in good agreement with the theoretically calculated energy values. The trans/cis configuration, the identity of the cyclometalated, and the alkynyl ligand influence on the absorption and emission properties of the complexes in solution, polystyrene (PS) films, and solid state are reported. All complexes are efficient triplet emitters in all media (except for trans-1a and trans-2a in CH2Cl2 solution at 298 K), with emission wavelengths depending mainly on the cyclometalated ligand in the region 473-490 nm (dfppy), 510-550 (ppy-CHO), and quantum yields (ϕ) ranging from 18.5 to 40.7% in PS films. The combined photophysical data and time-dependent density functional theory calculations (TD-DFT) at the excited-state T1 geometry reveal triplet excited states of 3L'LCT (C≡CR → C∧N)/3IL (C∧N) character with minor 3MLCT contribution. The dfppy (a) complexes show a greater tendency to aggregate in rigid media than the ppy-CHO (b) and the cis with respect to the trans, showing red-shifted structureless bands of 3MMLCT and/or excimer-like nature. Interestingly, trans-1a,2a and cis-1a,2a undergo significant changes in the ultraviolet (UV) and emission spectra with Hg2+ ions enabling their use for sensing of Hg2+ ions in solution. This is clearly shown by the hypsochromic shift and substantial decrease of the low-energy absorption band and an increase of the intensity of the emission in the MeCN solution upon the addition of a solution of Hg(ClO4)2 (1:5 molar ratio). Job's plot analysis estimated a 1:1 stoichiometry in the complexation mode of Hg2+ by trans-2a. The binding constant (log K) calculated for this system from absorption titration data resulted to be 2.56, and the limit of the detection (LOD) was 6.54 × 10-7 M.

An analytical model for solute transport in a large-strain aquitard affected by delayed drainage

This paper proposed a model for solute transport in a large-strain aquitard coupling effects of diffusion, adsorption, and consolidation processes. The analytical solutions describing the drawdown and solute transport in the aquitard were derived under the condition of variable drawdowns in adjacent confined aquifer. The breakthrough time (BTs) of solute transport in the large-strain aquitard (LD model) was analyzed, and compared with that of the rigid porous medium (ND model) before consolidation, and the equivalent rigid porous medium (NDf model) at end of the consolidation, respectively. Results reveal that greater Darcy flow velocity, stronger solute diffusivity, and weaker adsorption of soil particles result in shorter BTs of solute transport in the large-strain aquitard, and the impacts of specific storage and void ratio on the BTs are influenced by the adsorption of soil particles. Compared with the ND model, the delayed drainage accelerates solute transport with weak adsorption, while it has the opposite effect with strong adsorption. BTs predicted by the LD model is always smaller than that of the NDf model. It is also found that the larger leakage coefficient of the aquitard significantly enlarges the difference of BTs between the NDf and LD models (Δt), and the consolidation factor of the aquitard is positively correlated with the Δt. The ratio of Δt over the BTs of the LD model has a linear positive relationship with the average cumulative water release of the per unit volume aquitard under the fixed drawdown in the adjacent confined aquifer.

Luminescent Anionic Cyclometalated Organoplatinum (II) Complexes with Terminal and Bridging Cyanide Ligand: Structural and Photophysical Properties

We present the synthesis and characterization of two series of mononuclear heteroleptic anionic cycloplatinated(II) complexes featuring terminal cyanide ligand Q+[Pt(C^N)(p-MeC6H4)(CN)]- [C^N = benzoquinolate (bzq), Q+ = K+ 1 and NBu4+ 4; 2-phenylpyridinate (ppy), Q+ = K+ 2 and NBu4+ 5 and 2-(2,4- difluorophenyl)pyridinate (dfppy), Q+ = K+ 3 and NBu4+ 6] and a series of symmetrical binuclear complexes (NBu4)[Pt2(C^N)2(p-MeC6H4)2(μ-CN)] (C^N = bzq 7, ppy 8, dfppy 9). Compounds 5, 6, and 7-9 were further determined by single-crystal X-ray diffraction. There are no apparent intermolecular Pt···Pt interactions owing to the presence of bulky NBu4+ counterion. Slow crystallization of K[Pt(ppy)(p-MeC6H4)(CN)] 2 in acetone/hexane evolves with formation of yellow crystals, which were identified by single-crystal X-ray diffraction methods as the salt complex {[Pt(ppy)(p-MeC6H4)(CN)]2K3(OCMe2)4(μ-OCMe2)2}[Pt(ppy)(p-MeC6H4)(μ-CN)Pt(ppy)(p-MeC6H4)]·2acetone (10), featuring the binuclear anionic unit 8- neutralized by an hybrid inorganic-organometallic coordination polymer {[Pt(ppy)(p-MeC6H4)(CN)]2K3(OCMe2)4(μ-OCMe2)2}+. The photophysical properties of all compounds were recorded in powder, polystyrene film, and solution states with a quantum yield up to 21% for 9 in the solid state. All complexes displayed bright emission in rigid media, and for the interpretation of their absorption and emission properties, density functional theory (DFT) and time-dependent DFT calculations were applied.

Turn on of room temperature phosphorescence of donor-acceptor-donor type compounds via transformation of excited states by rigid hosts for oxygen sensing

A series of compounds with the different donor moieties (phenothiazine, phenoxazine and acridine) and 1,4-difluorobenzene unit as the acceptor were developed for optical sensors of oxygen. Among three new compounds, oxygen sensing ability of one compound 10,10'-(2,5-difluoro-1,4-phenylene)bis(10 H-phenothiazine) (2PS-2FPh) exhibiting strong room-temperature phosphorescence in rigid matrix Zeonex shows high sensitivity to low concentration of oxygen (<0.1%). To understand the reason of the high oxygen sensitivity of 2PS-2FPh, the effect of a rigid medium on conformational distortion was studied using a set of experimental and theoretical approaches. Doping 2PS-2FPh into Zeonex results in strong room-temperature phosphorescence in a vacuum with singlet-triplet splitting (ΔEST) widened to 0.47 eV as compared to 0.17 eV observed for the solution in 2-methyltetrahydrofuran. Molecular dynamic simulation with 2PS-2FPh doped in Zeonex indicates the increased molecular heterogeneity. Concomitantly, the hybrid local and charge transfer triplet state (3HLCT) becomes more local allowing the room temperature phosphorescence to be observed from locally excited triplet states. These results showed that conformational disorder and rigidity of the medium can significantly widen ΔEST of donor-acceptor-donor type molecules transforming 3HLCT into 3LE and thus facilitating the room-temperature phosphorescence and high oxygen sensitivity of 2PS-2FPh.

Sensitivity of acoustic parameters on the reflected signal from a rigid porous medium in the low-frequency range of ultrasound

Porous materials are two-phase media consisting of pores saturated with a fluid emerging from a solid skeleton. There are several parameters describing the porous medium. These parameters are classified into two categories: the high-frequency parameters and the low-frequency parameters. During the excitation by an acoustic wave, two cases can occur; the vibration of both phases simultaneously in the case where the structure is flexible, this case is well studied by Biot theory. For a rigid structure, it is the movement of the fluid that is taken into account; this last case is treated by the equivalent fluid theory which is a particular case of Biot theory. Previous work [Proc. Mtgs. Acoust. 45, 045004 (2021)] has shown the influence of the parameters involved in the corrected Johnson-Allard model recently introduced by Sadouki [Phys. Fluids 33, (2021)] on the transmitted signal from a rigid-porous material in the low-frequency regime of ultrasound. The objective of this work is to show, once again, the influence of the same parameters on the reflected signal by providing a comparative study between transmitted and reflected modes.

Existence of solutions for a quasilinear problem with fast nonlocal terms

In this paper, it is considered the existence of a solution for a nonlocal equation involving the p-Laplacian operator which is related to several applications such as vibration problems, flow of fluids through a homogeneous isotropic rigid porous medium, nuclear reactor's dynamics and in population dynamics. The approach is based on sub-supersolution arguments and Schauder's fixed point theorem. An important fact is that our result is valid for nonlocal terms which may exhibit a growth higher than p.

Nonconventional 1,8-Diazafluoren-9-One Aggregates for Green Light Enhancement in Hybrid Biocompatible Media.

Organic aggregates currently play a prominent role, mainly for their unique optoelectronic properties in the aggregated state. Such properties can be related to the aggregates’ structure and the molecular packing mode. In the literature, we have well-established models of H and J aggregates defined based on the molecular exciton model. However, unconventional aggregates, the most unrecognized forms, have been generating interest among researchers recently. Within unconventional aggregation, aggregation-induced emission systems (AIE) are considered. In the present work, we discuss the effect of the forming of unconventional aggregation together with the change in dye concentration on the surface energy characteristics of the materials. All materials were prepared as hybrid biocompatible thin films where the matrix is TiO2 or TiO2/carbon nanowalls (CNWs) with the incorporated dye in the form of 1,8-diazafluoren-9-one (DFO). Using the time-resolved emission spectra and the determination of surface parameters from contact angle measurements, we indicated the correlation between the changes in such parameters and the concentration of DFO dye in two types of TiO2 and TiO2/CNW structures. To examine the propensity of DFO for aggregation, the internal energy of the dye was assessed in several aggregate structures using Quantum chemistry calculations. The results emphasize that DFO is an attractive structure in the design of new fluorophores due to its low molecular weight, the presence of a nitrogen atom that provides good coordination properties, and the ability to form hydrogen bonds. Our studies show that when using suitable matrices, i.e., rigid media, it forms the preferred forms of aggregates in the excited state, characterized by high emission efficiency in the band maximum of around 550 nm.

A macroscopic model for immiscible two-phase flow in porous media

This work provides the derivation of a closed macroscopic model for immiscible two-phase, incompressible, Newtonian and isothermal creeping steady flow in a rigid and homogeneous porous medium without considering three-phase contact. The mass and momentum upscaled equations are obtained from the pore-scale Stokes equations, adopting a two-domain approach where the two fluid phases are separated by an interface. The average mass equations result from using the classical volume averaging method. A Green's formula and the adjoint Green's function velocity pair problems are used to obtain the pore-scale velocity solutions that are averaged to obtain the upscaled momentum balance equations. The macroscopic model is based on the assumptions of scale separation and the existence of a periodic representative elementary volume allowing a local description as usually postulated for upscaling. The macroscopic momentum equation in each phase includes the generalized Darcy-like dominant and viscous coupling terms and, importantly, an additional compensation term that accounts for surface tension effects to momentum transfer that is, otherwise, incompletely captured by the Darcy terms. This interfacial term, as well as the dominant and viscous coupling permeability tensors, can be predicted from the solutions of two associated closure problems that coincide with those reported in the literature. The relevance of the compensation term and the upscaled model validity are assessed by comparisons with direct numerical simulations in a model two-dimensional periodic structure. Upscaled model predictions are found to be in excellent agreement with direct numerical simulations.

Lid induced sloshing suppression and evaluation of wall stresses in a liquid storage tank including seismic soil‐structure interaction

AbstractAboveground liquid storage tanks are often found on weak compressive soil due to their proximity to harbours and rivers. These soil conditions lead to a high probability of significant soil‐structure interaction (SSI) under earthquake loading. In strong earthquakes, the transient partial separation of the tank base from the supporting medium (uplift) and chaotic liquid sloshing often cause damage to the tank wall. This experimental research determines the simultaneous effects of SSI and the restriction of sloshing on the development of hoop and axial stresses in the tank wall. A low‐density polyethylene tank with two different supporting foundation conditions, that is rigid and flexible, was tested using a shake table. A high‐density foam floating lid was utilised as a barrier to the development of sloshing enabling evaluation of the contribution of sloshing to wall stress development. The maximum experimentally determined stresses are compared with those from a nonlinear elastic spring‐mass model. The results reveal that a flexible supporting medium reduces the development of stresses by increasing the occurrence of uplift compared to that when the tank lies on a rigid supporting medium. Furthermore, restricting chaotic sloshing decreases both the maximum stress and uplift. The spring‐mass model predicts the maximum stresses with more accuracy when the tank is on a flexible than on a rigid supporting medium.

9‐(Diphenylphosphoryl)‐10‐(phenylethynyl)anthracene Derivatives: Synthesis and Implications for the Substituent and Solvent Effects on the Light‐Emitting Properties

AbstractHerein, we report a series of 9‐(diphenylphosphoryl)‐10‐(phenylethynyl)anthracenes (DPPPEAs) as novel fluorescent 9,10‐disubstituted anthracene derivatives. The DPPPEAs were prepared by Sonogashira coupling of (10‐bromoanthracen‐9‐yl)diphenylphosphine oxide with terminal arylacetylenes, and their structures were fully characterized. UV/Vis fluorescence spectroscopy and theoretical calculations were used to evaluate substituent effects on fluorescence properties of DPPPEAs. The nature of emissive excited state of DPPPEAs was found to vary greatly depending on the substituent, solvent, and temperature. Unsubstituted DPPPEA emitted intense fluorescence from locally excited (LE) state, whereas donor‐acceptor (D‐A) type DPPPEAs substituted with diphenylamino groups showed strong solvatofluorochromism derived from the charge‐transfer (CT) state. Notably, carbazolyl derivatives exhibited fluorescence from LE hybridized with CT state. The disappearance of CT emission in rigid media suggests that solvent reorganization plays a crucial role in producing large Stokes shifts of D‐A type derivatives. The DPPPEAs have also been found to function as annihilators in porphyrin‐sensitized triplet–triplet annihilation processes.

Two-equation continuum model of drying appraised by comparison with pore network simulations

A two-equation non-local-equilibrium (NLE) continuum model of isothermal drying is assessed by comparison with pore network simulations considering a rigid capillary porous medium that is fully saturated initially. This continuum model consists of a transport equation for the liquid and of a transport equation for the vapor. The two main variables are the liquid saturation and the vapor partial pressure. The two equations are coupled by a phase-change term and mass transport at the medium surface is modeled by considering the individual boundary conditions for the two continuum model equations. The macroscopic parameters that appear in the NLE continuum model include classical parameters such as the effective liquid and vapor diffusivities, as well as non-classical and new parameters such as the specific interfacial area and the fraction of dry surface pores. These parameters are determined for the porous microstructure corresponding to the cubic network used to perform the pore network simulations. The results obtained by the two-equation NLE continuum model are compared with pore network simulation data. Comparisons reveal that the two-equation NLE continuum model can capture with a reasonable degree of accuracy the NLE effect as well as the phase distributions and drying kinetics of the pore network model drying simulations.

Simulation of near-ground signals from a flying source on UAV over a building structure

Acoustic signals near the ground generated by a moving source on a fly-by UAV are simulated around a house. The simulation is carried out using a time-domain acoustics solver that can simulate acoustic propagations with the specified moving source, ground properties, and building geometries. The source on a UAV is approximated by a broadband source moving at a constant speed. The long-range three-dimensional computation is developed with a ground as a rigid or porous medium and a residential house with realistic geometries. Time histories and histograms of the near-ground sensors at different locations around the house are analyzed with their different behaviors due to Doppler shift, ground effect, and acoustic interference from the house structures. Comparisons will be made with literature results and available measured data.

Topology optimization for acoustic structures considering viscous and thermal boundary layers using a sequential linearized Navier–Stokes model

This study proposes a level set-based topology optimization method for designing acoustic structures with viscous and thermal boundary layers in perspective. Acoustic waves propagating in a narrow channel are damped by viscous and thermal boundary layers. To estimate these viscothermal effects, we first introduce a sequential linearized Navier–Stokes model based on three weakly coupled Helmholtz equations for viscous, thermal, and acoustic pressure fields. Then, the optimization problem is formulated, where a sound-absorbing structure comprising air and an isothermal rigid medium is targeted, and its sound absorption coefficient is set as an objective function. The adjoint variable method and the concept of the topological derivative are used to approximately obtain design sensitivity. A level set-based topology optimization method is used to solve the optimization problem. Two-dimensional numerical examples are provided to support the validity of the proposed method. Moreover, the mechanisms that lead to the high absorption coefficient of the optimized design are discussed.

Physical parameters influence on the transmitted signal through a rigid porous medium in the low-frequency range of ultrasound

The acoustic characterization of porous materials with rigid structure plays an important role in the prediction of the acoustic behavior of these media. In order to obtain an accurate prediction of its response as a function of frequency, several parametric models have been proposed. However, semi-phenomenological models are the most used to describe the acoustic behavior of porous materials with rigid or flexible structures according to a certain number of macroscopic physical properties related to the internal structure of the material and essential for their valuation. Among these models, the one proposed by Johnson et al. to describes the complex density of an acoustic porous material with an immobile skeleton having arbitrary pore shapes. The objective of this work is to study the effect of these parameters involved in Johnson's model as well as other new parameters, recently introduced by Sadouki [ Phys. Fluids 33, (2021)), on the transmitted signal in the low-frequency regime of ultrasound.

Mini Hydraulic Press

A hydraulic press is a device (see machine press) using a hydraulic cylinder to generate a compressive force. It uses the hydraulic equivalent of a mechanical lever, and was also known as a Bramah press after the inventor, Joseph Bramah, of England. He invented and was issued a patent on this press in 1795. A hydraulic press is a machine using a hydraulic cylinder to generate a compressive force. Frame, hydraulic cylinder and press table are the main components of the hydraulic press. Hence a hydraulic press is a machine that makes use of the pressure exerted on the fluids to crush, straighten or mould. The concept of the hydraulic press is based on Pascal's theory, which states that when pressure is applied on fluids in an enclosed system, the pressure throughout the system always remains constant. In hydraulic press, the force generation, transmission and amplification are achieved using fluid under pressure. The liquid system exhibits the characteristics of a solid and provides a very positive and rigid medium of power transmission and amplification. In a simple application, a smaller piston transfers fluid under high pressure to a cylinder having a larger piston area, thus amplifying the force. There is easy transmissibility of large amount of energy with practically unlimited force amplification.