Shizheng Liu. Qingbo Liu. Nov , 11 : 10 pages. Published Online: September 16, Article history Received:. Views Icon Views. Abstract Pressure gain combustion PGC is considered to be a potential technology to increase the cycle efficiency of gas turbine. Issue Section:. You do not currently have access to this content. Learn about subscription and purchase options. Product added to cart. Accepted Manuscript Alert. Article Activity Alert. Cited By Google Scholar. Gas Turbines Power October Mech July, Pressure Vessel Technol May, Pressure Vessel Technol November, Offshore Mech. Evaluations were made before the treatment, immediately afterwards, and three months after treatment.
These evaluations were always performed by the same examiner. The evaluations consisted of:. There were no differences between groups 1 and 2 with regard to gender, age, physical activity, ethnicity, side affected or body mass index BMI. Both groups showed improvement of pain symptoms including reduced number of episodes of pain per week Table 1 and hours of pain per day Table 2. There were decreases in the intensity of morning pain Table 3 , general pain Table 4 and pain in the orthostatic position Table 5 , as evaluated using the VAS.
There was a decrease in the intensity of pain in the calcaneus Table 6 and calf Table 6 when measured using Fischer's algometer. Most patients had decreased their intake of analgesics by the final evaluation at three months after treatment Table 7. There was no statistically significant difference between the groups in any of the parameters used for evaluation. The plantar fascia is one of the most important static structures that support the medial longitudinal arch.
Plantar fasciitis occurs as a result of repetitive microtrauma at the origin of the medial tuberosity of the calcaneus; traction forces during support lead to an inflammatory process that results in fibrosis and degeneration.
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Plantar fasciitis is associated with obesity and the climacterium. The occurrence of plantar fasciitis is related to professional and leisure activities that require support of body weight and is not related to loss of strength, muscle trophism or joint range of motion ROM. None of the patients in this study presented loss of strength or decreased ROM. Morning pain is an important evaluation criterion. In the present study, all patients quantified their morning pain as greater than or equal to five on the VAS before treatment.
Plantar fasciitis leads to lateral body weight support on the foot or forefoot supported on the toes during gait because of pain in the medial region of the calcaneus or at the proximal insertion of the plantar fascia; this leads to chronic shortening of the Achilles tendon and pain in the medial portion of the gastrocnemius. This latter finding is in contrast to previous reports that pain was present in the calcaneus and gastrocnemius of most patients. The combination of fascitis with overweight may enhance the effects of the latter in altering postural balance.
In many cases, planter fasciitis is bilateral. Chronic plantar fasciitis symptoms lasting for more than three months responds better to shockwave treatment than does the acute form less than three months of symptoms. Thickening of the plantar fascia to more than 4 mm has been correlated with greater intensity of pain and functional limitation, but this relationship was not observed in the present study.
The thickness of the plantar fascia in the present study ranged from 4 mm to 9 mm, but without any correlation with the intensity of the pain. Furthermore, no decrease in the ROM of the first metatarsal-phalangeal joint was observed, in contrast to the findings reported in the literature. Surgical treatment of plantar fasciitis is rare. The applied doses ranged from 1. Tabela 8. The aim of the present study was to comparatively evaluate shockwaves with conventional physiotherapeutic treatment for plantar fasciitis.
All patients were advised to perform active stretching of the gastrocnemius twice per day to improve ankle flexibility, but only group 1 conventional physiotherapy underwent a kinesiotherapy regimen under guidance from a physiotherapist at all treatment sessions. Reinforcement of instructions by a physiotherapist at the ten treatment sessions might have influenced the good results observed for this group.
More specifically, the constancy of such guidance might have greatly contributed to adherence to the exercise program and to the change of habits. Although the quality of this treatment depends on the physiotherapist, it gives good results when applied carefully and judiciously. In group 2 shockwave therapy , the patients were individually advised to perform active stretching of the gastrocnemius, but they did not receive any specific kinesiotherapy regimen during the treatment sessions and did not have any subsequent follow-up.
All guidance was given during the three treatment sessions and at the assessments. Shockwave therapy might be more efficient for treatment of plantar fasciitis pain than conventional physiotherapy, but comprehensive rehabilitation programs that are implemented carefully and with good guidance increase patient adherence and promote both pain reduction and functional improvement. There was no difference in the efficacy of the two treatments, but the more immediate effect of shockwave therapy provided faster relief from pain and incapacitation.
For shockwave treatment to be effective and long-lasting, it must be complemented with the use of insoles for impact absorption, as well as changes in footwear, weight loss, restrictions on running or walking long distances and stretching of the gastrocnemius and plantar fascia. Better functioning of the foot and ankle, particularly with regard to gait, is of prime importance for maintaining the improvements gained by therapy.
Correct clinical and functional diagnosis of plantar fasciitis together with a simple but well implemented rehabilitation program is a good approach to treating this disorder. It is therefore not always necessary to utilize sophisticated resources or technology to achieve optimal results. The two evaluated treatments were effective for reducing pain and incapacitation among patients with plantar fasciitis for at least three months after treatment.
Shock wave therapy Orthotripsy in musculoskeletal disorders. Clin Orthop Relat Res. Principles of shock wave therapy. Dynamic compression tests have also been performed using the free-falling drop hammer. The results are compared with those in the static compression tests. Advances in ferroelectric polymers for shock compression sensors. Our studies of the shock compression response of PVDF polymer are continuing in order to understand the physical properties under shock loading and to develop high fidelity, reproducible, time-resolved dynamic stress gauges.
New PVDF technology, new electrode configurations and piezoelectric analysis have resulted in enhanced precision gauges. The piezoelectric response of shock compressed PVDF gauges 1 mm 2 in active area has been studied and yielded well-behaved reproducible data up to 20 GPa. Analysis of the response of these gauges in the open-quotes thin mode regimeclose quotes using a Lagrangian hydrocode will be presented.
P VDF-TrFE copolymers exhibit unique piezoelectric properties over a wide range of temperature depending on the composition. Their properties and phase transitions are being investigated. Emphasis of the presentation will be on key results and implications. Temperature measurement of tin under shock compression.
The results of pyrometric measurements performed at the interface of a tin target with a LiF window material are presented for stresses ranging from 38 to 55 GPa. The purpose of the study is to analyze the part of the interface in the temperature measurement by a multi-channel pyrometric device. Shock tubes: compressions in the low pressure chamber. The gas shock tube used in these experiments consists of a low pressure chamber and a high pressure chamber, divided by a metal-diaphragm-to-rupture.
In contrast to the shock mode of operation, where incident and reflected shocks in the low pressure chamber are studied which occur within 3. An order parameter is linked simultaneously to densification and Inelastic response of silicon to shock compression. The elastic and inelastic response of  oriented silicon to laser compression has been a topic of considerable discussion for well over a decade, yet there has been little progress in understanding the basic behaviour of this apparently simple material. We present experimental x-ray diffraction data showing complex elastic strain profiles in laser compressed samples on nanosecond timescales.
We also present molecular dynamics and elasticity code modelling which suggests that a pressure induced phase transition is the cause of the previously reported 'anomalous' elastic waves. Moreover, this interpretation allows for measurement of the kinetic timescales for transition. This model is also discussed in the wider context of reported deformation of silicon to rapid compression in the literature.
Failure Waves in Shock-Compressed Glasses. The failure wave is a network of cracks that are nucleated on the surface and propagate into the elastically stressed body. It is a mode of catastrophic fracture in an elastically stressed media whose relevance is not limited to impact events. In the paper, main properties of the failure waves are summarized and discussed. It has been shown that the failure wave is really a wave process which is characterized by small increase of the longitudinal stress and corresponding increments of the particle velocity and the density.
The propagation velocity of the failure wave is less than the sound speed; it is not directly related to the compressibility but is determined by the crack growth speed. The failure wave is steady if the stress state ahead of it is supported unchanging. In some sense the process is similar to a subsonic combustion wave. Computer simulations based on the phenomenological combustion-like model reproduces well all kinematical aspects of the phenomenon. Formation of a compressible vortex ring and generation of sound associated with it is studied experimentally.
Impulse of a shock wave is used to generate a vortex ring from the open end of a shock -tube. Vortex ring formation process has been studied in details using particle image Velocimetry PIV. As the shock wave exits the tube it diffracts and expands. A circular vortex sheet forms at the edge and rolls up into a vortex ring.
Far field microphone measurement shows that the acoustic pressure consists of a spike due to shock wave followed by a low frequency pressure wave of decaying nature, superimposed with high frequency pressure wave. Acoustic waves consist of waves due to expansion, waves formed in the tube during diaphragm breakage and waves associated with the vortex ring and shear-layer vortices.
Unsteady evolution of the vortex ring and shear-layer vortices in the jet behind the ring is studied by measuring the velocity field using PIV. Corresponding vorticity field, circulation around the vortex core and growth rate of the vortex core is calculated from the measured velocity field.
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The velocity field in a compressible vortex ring differs from that of an incompressible ring due to the contribution from both shock and vortex ring. The size effects upon shock plastic compression of nanocrystals. For the first time a theoretical analysis of scale effects upon the shock plastic compression of nanocrystals is implemented in the context of a dislocation kinetic approach based on the equations and relationships of dislocation kinetics.
This dependence is valid in the case of elastic stress relaxation on account of emission of dislocations from single-pole Frank-Read sources near the crystal surface. Clattering motion that occurs when flat objects strike the ground at an oblique angle is studied through a simple, tractable, model of a rigid bar with arbitrary, but symmetric, mass distribution and coefficient of restitution.
The maximum velocity changes, or velocity shocks , that occur at various locations of the bar as it clatters to rest, are presented. It is shown that different parts of the bar can be subjected to sequences of velocity changes that are both higher, and lower, than those Shock compression experiments on Lithium Deuteride single crystals. The experimental measurements are compared with recent density functional theory calculations as well as a new tabular equation of state developed at Los Alamos National Labs.
Electrical conductivity measurements in shock compressed liquid nitrogen. The electrical conductivity of shock compressed liquid nitrogen was measured in the pressure range 20 to 50 GPa using a two-stage light-gas gun. The conductivities covered a range 4 x 10 -2 to 1 x 10 2 ohm -1 cm The data are discussed in terms of a liquid semiconductor model below the onset of the dissociative phase transition at 30 GPa.
Behavior of porous tungsten under shock compression at room temperature.
This work reports the results of room-temperature shock-compression experiments on porous tungsten. The main features of the results are as follows: 1 porous tungsten behaves as a linear elastic material to 1. Full Text Available Clattering motion that occurs when flat objects strike the ground at an oblique angle is studied through a simple, tractable, model of a rigid bar with arbitrary, but symmetric, mass distribution and coefficient of restitution. It is shown that different parts of the bar can be subjected to sequences of velocity changes that are both higher, and lower, than those encountered in a single clatter-free impact.
It is shown, through example, that a significant safe zone can be created in the center of the product by configuring it to have a low moment of inertia and by minimizing coefficient of restitution. Shock compression of nitrobenzene; Nitoro benzen no shogeki asshoku. Explosive plane-wae generators were used for plane shock wave generation. Stress relaxation in vanadium under shock and shockless dynamic compression.
Evolutions of elastic-plastic waves have been recorded in three series of plate impact experiments with annealed vanadium samples under conditions of shockless and combined ramp and shock dynamic compression. The shaping of incident wave profiles was realized using intermediate base plates made of different silicate glasses through which the compression waves were entered into the samples. Measurements of the free surface velocity histories revealed an apparent growth of the Hugoniot elastic limit with decreasing average rate of compression.
A set of obtained data show that the current value of the Hugoniot elastic limit and plastic strain rate is rather associated with the rate of the elastic precursor decay than with the local rate of compression. The study has revealed the contributions of dislocation multiplications in elastic waves. It has been shown that independently of the compression history the material arrives at the minimum point between the elastic and plastic waves with the same density of mobile dislocations.
The fluorite crystal structure is a textbook lattice that is observed for many systems, such as CaF2, Mg2 Si, and CeO2. Specifically, CaF2 is a useful material for studying the fluorite system because it is readily available as a single crystal. Under static compression , CaF2 is known to have at least three solid phases: fluorite, cotunnite, and a Ni2 In phase. Along the Hugoniot CaF2 undergoes a fluorite to cotunnite phase transition, however, at higher shock pressures it is unknown whether CaF2 undergoes another solid phase transition or melts directly from the cotunnite phase.
In this work, we conducted planar shock compression experiments on CaF2 using Sandia's Z-machine and a two-stage light gun up to GPa. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.
Femtosecond visualization of lattice dynamics in shock-compressed matter. The ultrafast evolution of microstructure is key to understanding high-pressure and strain-rate phenomena. However, the visualization of lattice dynamics at scales commensurate with those of atomistic simulations has been challenging.
We capture the evolution of the lattice from a one-dimensional 1D elastic to a 3D plastically relaxed state within a few tens of picoseconds, after reaching shear stresses of 18 GPa. Our in situ high-precision measurement of material strength at spatial Molecular dynamics study of shock compression in porous silica glass.
The shock response of porous amorphous silica is investigated using classical molecular dynamics, over a range of porosity ranging from fully dense 2. In the lowest initial densities, after an initial compression response, the systems expand with increased pressure. These results show good agreement with experiments.
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Mechanisms leading to enhanced densification will be explored, which appear to differ from mechanisms observed in similar studies in silicon. Sandia National Laboratories is a multi mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U. Expansion and compression shock wave calculation in pipes with the C. The Control Variables Method for fluid transients computations has been used to compute expansion and compression shock waves propagations.
In this paper, first analytical solutions for shock wave and rarefaction wave propagation are detailed. Then after a rapid description of the C. Vibrational spectroscopy of shock-compressed fluid N2 and O2. Single-pulse multiplex coherent anti-Stokes Raman scattering CARS was used to observe the vibrational spectra of liquid N 2 shock-compressed to several pressures and temperatures up to 41 GPa and K and liquid O 2 shock-compressed to several pressures and temperatures up to 10 GPa and K.
For N 2 , the experimental spectra were compared to synthetic spectra calculated using a semiclassical model for CARS intensities and estimated vibrational frequencies, peak Raman susceptibilities, and Raman line widths. The question of excited state populations in the shock-compressed state is addressed.
Anomalous elastic response of silicon to uniaxial shock compression on nanosecond time scales. We have used x-ray diffraction with subnanosecond temporal resolution to measure the lattice parameters of orthogonal planes in shock compressed single crystals of silicon Si and copper Cu. In contrast, shocked Cu shows prompt hydrostaticlike compression. These results are consistent with simple estimates of plastic strain rates based on dislocation velocity data.
Bridgman's contributions to the foundations of shock compression of condensed matter. Nellis, W J, E-mail: nellis physics. Based on his year career in static high-pressure research, P. Bridgman PWB is the father of modern high-pressure physics. What is not generally recognized is that Bridgman was also intimately connected with establishing shock compression as a scientific tool and he predicted major events in shock research that occurred up to 40 years after his death. In the first phase transition under shock compression was reported in Fe at 13 GPa kbar.
The scientific legitimacy of shock compression resulted 5 years later when static high-pressure researchers confirmed with x-ray diffraction the existence of epsilon-Fe. Once PWB accepted the fact that shock waves generated with chemical explosives were a valid scientific tool, he immediately realized that substantially higher pressures would be achieved with nuclear explosives. He included his ideas for achieving higher pressures in articles published a few years after his death. Altshuler eventually read Bridgman's articles and pursued the idea of using nuclear explosives to generate super high pressures, which subsequently morphed today into giant lasers.
PWB also anticipated combining static and shock methods, which today is done with pre- compression of a soft sample in a diamond anvil cell followed by laser-driven shock compression. One variation of that method is the reverberating- shock technique, in which the first shock pre- compresses a soft sample and subsequent reverberations isentropically compress the first- shocked state. Investigation of shock compressed plasma parameters by interaction with magnetic field. The Hall effect parameters in shock compressed air, helium and xenon have been estimated and results of experiments with air and helium plasma are presented.
Explosively driven shock tubes were used for the generation of strong shock waves. To obtain magnetic field a solenoid was winded over the shock tube. Calculations of dense shock compressed plasma parameters were carried out to plan the experiments. The reflected shock waves technique was used in the experiments with helium. Results on measurements of electrical conductivity and electron concentration of helium are presented. Assessment of high-resolution methods for numerical simulations of compressible turbulence with shock waves.
Flows in which shock waves and turbulence are present and interact dynamically occur in a wide range of applications, including inertial confinement fusion, supernovae explosion, and scramjet propulsion. Accurate simulations of such problems are challenging because of the contradictory requirements of numerical methods used to simulate turbulence, which must minimize any numerical dissipation that would otherwise overwhelm the small scales, and shock -capturing schemes, which introduce numerical dissipation to stabilize the solution.
The objective of the present work is to evaluate the performance of several numerical methods capable of simultaneously handling turbulence and shock waves. The results indicate that the WENO methods provide sharp shock profiles, but overwhelm the physical dissipation. The hybrid method is minimally dissipative and leads to sharp shocks and well-resolved broadband turbulence, but relies on an appropriate shock sensor. Artificial diffusivity methods in which the artificial bulk viscosity is based on the magnitude of the strain-rate tensor resolve vortical structures well but damp dilatational modes in compressible turbulence; dilatation-based artificial bulk viscosity methods significantly improve this behavior.
For well-defined shocks , the shock fitting approach yields good results. A comparative study on shock compression of nanocrystalline Al and Cu: Shock profiles and microscopic views of plasticity. Shock compressions of nanocrystalline nc metals Al and Cu with the same grain size and texture are studied by using molecular dynamics simulations. Results have revealed that the shock front of both Al and Cu can be divided into three stages: elastic, grain-boundary-mediated, and dislocation-mediated plastic deformation.
The transition planes among these three stages are proven to be non-planar by two-dimensional shock response analysis, including local stress, shear, temperature, and atom configuration. The difference between shocked Al and Cu is that the rise rate of the elastic stage of Cu is slightly higher than that of Al, and that the shock -front width of Al is wider than Cu at the same loading conditions.
For the plastic stage, the dislocation density of shocked Al is lower than Cu, and the contribution of grain-boundary-mediated plasticity to shock front and strain for nc Al is more pronounced than for nc Cu. These results are explained through intrinsic material properties and atomistic analysis of the plastic process. In the case of the shocked Al sample, partial dislocations, perfect dislocations, and twins are observed, but few evidence of perfect dislocations and twins are observed in the shocked Cu. Compression of interstellar clouds in spiral density-wave shocks.
A mechanism of triggering star formation by galactic shocks is discussed. The possibilty that shocks may form along spiral arms in the gaseous component of a galactic disk is by now a familiar feature of spiral wave theory. It was suggested by Roberts that these shocks could trigger star formation in narrow bands forming a coherent spiral pattern over most of the disk of a galaxy. Some results of computer simulations of such a triggering process for star formation are reported.
Heterogeneous free-surface profile of B4C polycrystal under shock compression. Observations of the free-surface behavior under shock compression by the gapped-flat mirror method were performed on B 4 C and Si 3 N 4 ceramics to study their shock -yielding properties. Similar profiles for Si 3 N 4 polycrystals were smooth.
Such profiles for B 4 C polycrystals were also observed in the elastic region. It is suggested that these observations reflect the heterogeneous nature of shock compression in solids, and further indicate that a macroscopic slip system plays an important role in the elastoplastic transition of B 4 C material under shock compression and decompression.
The effect of shock dynamics on compressibility of ignition-scale National Ignition Facility implosions. Zylstra, A. The effects of shock dynamics on compressibility of indirect-drive ignition-scale surrogate implosions, CH shells filled with D 3 He gas, have been studied using charged-particle spectroscopy.
Spectral measurements of D 3 He protons produced at the shock -bang time probe the shock dynamics and in-flight characteristics of an implosion. The proton shock yield is found to vary by over an order of magnitude. This model-inferred differential bang time contradicts radiation-hydrodynamic simulations, which predict constant — ps differential independent of coasting time; this result is potentially explained by uncertainties in modeling late-time ablation drive on the capsule. Time-resolved shock compression of porous rutile: Wave dispersion in porous solids.
The technique uses a copper capsule to contain the sample which has PVDF gauge packages in direct contact with front and rear surfaces. A precise measure is made of the compressive stress wave velocity through the sample, as well as the input and propagated shock stress. Initial density is known from sample preparation, and the amount of shock-compression is calculated from the measurement of shock velocity and input stress.
Shock states and re- shock states are measured. Observed data are consistent with previously published high pressure data. Propagated stress-pulse rise times vary from to nsec. In order to provide broader scientific recognition and to advance the science of shock compressed condensed matter, a group of American Physical Society APS members worked within the Society to make this field an active part of the APS. Individual papers were presented at APS meetings starting in the 's and shock wave sessions were organized starting with the Pasadena meeting.
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Shock wave topical conferences began in in Pullman, WA. Signatures were obtained on a petition in from a balanced cross-section of the shock wave community to form an APS Topical Group TG. This action firmly aligned the shock wave field with a major physical science organization. The topical group organizes a shock wave topical conference in odd numbered years while participating in shock wavehigh pressure sessions at APS general meetings in even numbered years.
A soap film shock tube to study two-dimensional compressible flows. Wen, C. A new experimental approach to the study of the two-dimensional compressible flow phenomena is presented. In this technique, a variety of compressible flows were generated by bursting plane vertical soap films. An aureole and a '' shock wave'' preceding the rim of the expanding hole were clearly observed using traditional high-speed flash photography and a fast line-scan charge coupled device CCD camera.
The moving shock wave images obtained from the line-scan CCD camera were similar to the x-t diagrams in gas dynamics.
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The moving shock waves cause thickness jumps and induce supersonic flows. Photographs of the supersonic flows over a cylinder and a wedge are presented. The results suggest clearly the feasibility of the ''soap film shock tube''. Bacterial survival following shock compression in the GigaPascal range. Hazael, Rachael; Fitzmaurice, Brianna C. The possibility that life can exist within previously unconsidered habitats is causing us to expand our understanding of potential planetary biospheres.
Significant populations of living organisms have been identified at depths extending up to several km below the Earth's surface; whereas laboratory experiments have shown that microbial species can survive following exposure to GigaPascal GPa pressures. Understanding the degree to which simple organisms such as microbes survive such extreme pressurization under static compression conditions is being actively investigated. The survival of bacteria under dynamic shock compression is also of interest. Such studies are being partly driven to test the hypothesis of potential transport of biological organisms between planetary systems.
Shock compression is also of interest for the potential modification and sterilization of foodstuffs and agricultural products. Here we report the survival of Shewanella oneidensis bacteria exposed to dynamic shock compression. The samples examined included: a a "wild type" WT strain and b a "pressure adapted" PA population obtained by culturing survivors from static compression experiments to MPa.
Following exposure to peak shock pressures of 1. The data were compared with previous results in which the same bacterial samples were exposed to static pressurization to the same pressures, for 15 minutes each. The results indicate that shock compression leads to survival of a significantly greater proportion of both WT and PA organisms.
One reason for this can involve the crossover from deformable to rigid solid-like mechanical relaxational behavior that occurs for. Shock compression of a recrystallized anorthositic rock from Apollo Hugoniot measurements on 15,, a recrystallized and brecciated gabbroic anorthosite, yield a value of the Hugoniot elastic limit HEL varying from 45 to 70 kbar as the final shock pressure is varied from 70 to kbar. Above the HEL and to kbar, the pressure-density Hugoniot is closely described by a hydrostatic equation of state constructed from ultrasonic data for single-crystal plagioclase and pyroxene.
Above kbar, the Hugoniot states indicate that a series of one or more shock -induced phase changes are occurring in the plagioclase and pyroxene. From Hugoniot data for both the single-crystal minerals and the Frederick diabase, we infer that the shock -induced high-pressure phases in 15, probably consists of a 3. Shock wave compression and metallization of simple molecules. In this paper we combine shock wave studies and metallization of simple molecules in a single overview.
The unifying features are provided by the high shock temperatures which lead to a metallic-like state in the rare gases and to dissociation of diatomic molecules. In the case of the rare gases, electronic excitation into the conduction band leads to a metallic-like inert gas state at lower than metallic densities and provides information regarding the closing of the band gap.
Diatomic dissociation caused by thermal excitation also leads to a final metallic-like or monatomic state. Ina ddition, shock wave data can provide information concerning the short range intermolecular force of the insulator that can be useful for calculating the metallic phase transition as for example in the case of hydrogen. Laser driven single shock compression of fluid deuterium from 45 to GPa. An Al impedance match model derived from a best fit to absolute Hugoniot data has been used to quantify and minimize the systematic errors caused by uncertainties in the high-pressure Al equation of state.
Previous laser-driven double- shock results are found to be in good agreement with these single- shock measurements over the entire range under study. Both sets of laser- shock data indicate that deuterium undergoes an abrupt increase in compression at around GPa.
Sleeboom, Jelle J. We use dedicated microfluidic devices to expose soft hydrogel particles to a rapid change in the externally applied osmotic pressure and observe a surprising, nonmonotonic response: After an initial rapid compression , the particle slowly reswells to approximately its original size.
We theoretically account for this behavior, enabling us to extract important material properties from a single microfluidic experiment, including the compressive modulus, the gel permeability, and the diffusivity of the osmolyte inside the gel. We expect our approach to be relevant to applications such as controlled release, chromatography, and responsive materials.
Compression and reswelling of microgel particles after an osmotic shock. Sleeboom, J. We use dedicated microfluidic devices to expose soft hydrogel particles to a rapid change in the externally applied osmotic pressure and observe a non-monotonic response: After an initial rapid compression the particle slowly reswells to approximately its original size. Using a simple.
Shock compression and flash-heating of molecular adsorbates on the picosecond time scale. An ultrafast nonlinear coherent laser spectroscopy termed broadband multiplex vibrational sum-frequency generation SFG with nonresonant suppression was employed to monitor vibrational transitions of molecular adsorbates on metallic substrates during laser-driven shock compression and flash-heating.
Adsorbates were in the form of well-ordered self-assembled monolayers SAMs and included molecular explosive simulants, such as nitroaromatics, and long chain-length alkanethiols. Shock pressures were estimated via comparison with frequency shifts observed in the monolayer vibrational transitions during hydrostatic pressure measurements in a SiC anvil cell.
Molecular dynamics during flash-heating and shock loading were probed with vibrational SFG spectroscopy with picosecond temporal resolution and sub-nanometer spatial resolution. Flash-heating studies of 4-nitrobenzenethiolate NBT on Au provided insight into effects from hot-electron excitation of the molecular adsorbates at early pump-probe delay times.
In addition, flash-heating studies of alkanethiolates demonstrated chain disordering behaviors as well as interface thermal conductances across the Au-SAM junction, which was of specific interest within the context of molecular electronics. Shock compression studies of molecular explosive simulants, such as 4-nitrobenzoate NBA , demonstrated the proficiency of this technique to observe shock -induced molecular dynamics, in this case orientational dynamics, on the picosecond time scale.
Results validated the utilization of these refined shock loading techniques to probe the shock. Multiple investigations have discovered that tita - nium diboride demonstrates a rather unique It has been suggested  that pore collapse may be an important source of inelasticity in tita - nium diboride. On the failure of NiAl bicrystals during laser-induced shock compression.
Circular NiAl bicrystal samples with random misorientation were grown using a modified Czochralski technique and samples were prepared for shock compression at moderate pressures shock compression. This revealed that a nanocrystalline region with a grain size of nm formed on a thin layer at the drive surface following the plasma expansion phase of the laser-induced shock. TEM in the bulk of one grain showed that plastic deformation occurred in a periodic fashion through propagation of dislocation clusters. Cracking on the free surface of the samples revealed a clear grain boundary affected zone GBAZ due to scattering of the shock wave and variations in wave speed across the inclined boundary.
Damage tended to accumulate in the grain into which the elastic wave refracted. This damage accumulation corresponds well to the regions in which the transmitted waves impinged on the free surface as predicted by elastic scattering models. Shock compression experiments on Lithium Deuteride LiD single crystals.
Shock compression experiments in the few hundred GPa multi-Mbar regime were performed on Lithium Deuteride single crystals. The experimental measurements are compared with density functional theory calculations, tabular equation of state models, and legacy nuclear driven results that have been reanalyzed using modern equations of state for the shock wave standards used in the experiments. High-energy synchrotron X-ray radiography of shock-compressed materials. Rutherford, Michael E. This presentation will discuss the development and application of a high-energy 50 to keV synchrotron X-ray imaging method to study shock-compressed , high-Z samples at Beamline I12 at the Diamond Light Source synchrotron Rutherford-Appleton Laboratory, UK.
Shock waves are driven into materials using a portable, single-stage gas gun designed by the Institute of Shock Physics. Following plate impact, material deformation is probed in-situ by white-beam X-ray radiography and complimentary velocimetry diagnostics. Numerical investigation on target implosions driven by radiation ablation and shock compression in dynamic hohlraums. In a dynamic hohlraum driven inertial confinement fusion ICF configuration, the target may experience two different kinds of implosions.
One is driven by hohlraum radiation ablation, which is approximately symmetric at the equator and poles. The second is caused by the radiating shock produced in Z-pinch dynamic hohlraums, only taking place at the equator. To gain a symmetrical target implosion driven by radiation ablation and avoid asymmetric shock compression is a crucial issue in driving ICF using dynamic hohlraums. It is known that when the target is heated by hohlraum radiation, the ablated plasma will expand outward. The pressure in the shocked converter plasma qualitatively varies linearly with the material temperature.
However, the ablation pressure in the ablated plasma varies with 3. Therefore, as the hohlraum temperature increases, the ablation pressure will eventually exceed the shock pressure, and the expansion of the ablated plasma will obviously weaken the shock propagation and decrease its velocity after propagating into the ablator plasma. Consequently, longer time duration is provided for the symmetrical target implosion driven by radiation ablation.
In this paper these processes are numerically investigated by changing drive currents or varying load parameters. The simulation results show that a critical hohlraum radiation temperature is needed to provide a high enough ablation pressure to decelerate the shock , thus providing long enough time duration for the symmetric fuel compression driven by radiation ablation. Bright emissive core-shell spherical microparticles for shock compression spectroscopy. Experiments were performed to study the response to shock compression of rhodamine 6G R6G dye encapsulated in 1. When R6G was encapsulated in microspheres, the emission intensity under steady-state irradiation the brightness was 3.
At least part of the brightness improvement was caused by an enhanced radiative rate.