Plastic Spheres Research Articles

Bioaccumulation, transfer, and impacts of microplastics in aquatic food chains

Plastics have become a pervasive global contaminant since the mid-20th century, causing harm to organisms at all levels. Preventative measures to reduce plastic pollution and awareness-raising campaigns about the damaging effects of plastic debris on the environment and its inhabitants are crucial; however, most plastic assessments focus on singular trophic levels. Microplastics, tiny plastic particles ranging from 25 μm to 5 mm, have emerged as a widespread form of pollution found in ecosystems worldwide. They can enter the environment directly or through the breakdown of larger plastic debris and are thought to be mistaken for food by foraging animals. This leads to microplastics circulating through ecosystems via direct and indirect consumption, ultimately impacting even higher-order predators. Here, we assess the impacts of microplastics on Chlorophyll a concentrations, algal community structure, copepod survivorship, and fish behavior in experimental trials, in addition to simulated top-predator foraging success on plastic-exposed fish. Our results indicate that microplastics have detrimental effects on algal growth and copepod survival. We also observed the trophic transmission of small plastic spheres from copepods to fish predators, highlighting a concerning pathway for microplastic pollution within aquatic ecosystems, where fish consumed plastics through direct and indirect means. Primary consumers, like copepods, face dual pressures from top-down forcing, as they are preferred over plastic particles as food sources, and bottom-up resource depletion, as algal food supplies can be limited by microplastic exposure. Our findings demonstrate the system-wide impacts that can occur when microplastics are included in food chains and underscore the urgent need for comprehensive strategies to mitigate the entry of plastic debris into aquatic ecosystems.

Linear Contact Load Law of an Elastic–Perfectly Plastic Half-Space vs. Sphere under Low Velocity Impact

The impact of contact between two elastic–plastic bodies is highly complex, with no established theoretical contact model currently available. This study investigates the problem of an elastic–plastic sphere impacting an elastic–plastic half-space at low speed and low energy using the finite element method (FEM). Existing linear contact loading laws exhibit significant discrepancies as they fail to consider the impact of elasticity and yield strength on the elastic–plastic sphere. To address this limitation, a novel linear contact loading law is proposed in this research, which utilizes the concept of equivalent contact stiffness rather than the conventional linear contact stiffness. The theoretical expressions of this new linear contact loading law are derived through FEM simulations of 150 sphere and half-space impact cases. The segmental linear characteristics of the equivalent contact stiffness are identified and fitted to establish the segmental expressions of the equivalent contact stiffness. The new linear contact loading law is dependent on various factors, including the yield strain of the half-space, the ratio of elastic moduli between the half-space and sphere, and the ratio of yield strengths between the half-space and sphere. The accuracy of the proposed linear contact loading law is validated through extensive Finite Element Method simulations, which involve an elastic–plastic half-space being struck by elastic–plastic spheres with varying impact energies, sizes, and material combinations.

Numerical modelling of contact adhesion in a random assembly of elastic–plastic particles

The prediction of tensile strength properties of powder compacts remains an important industrial issue. In particular, one of the main problems of the powder compaction process is the failure of compacts. Indeed, some powder compacts exhibit cracks which appear during compaction. Such defects occur due to localised tensile or shear stresses, for example close to geometrical singularities. They are also related to the ability of a powder to create enough adhesion at contacts between particles to withstand tensile stresses. Therefore, cracks are a consequence of phenomena occurring at the particle scale and below, down to the molecular scale. To help understanding this mechanism, a particle-scale, numerical method called the multi-particle finite-element method was developed using the finite-element software suite Abaqus (Abaqus 6.14 Documentation, 2016). Such a method allowed to explicitly model the microstructure of a granular media idealised as an assembly of elastic–plastic spheres. The particles were meshed such that their deformations were fully taken into account, using a continuum-mechanics-based material model. The interactions between particles were managed using finite-element contact formulations. A multi-scale, adhesive contact model was developed based on the literature and implemented into the multi-particle finite-element code. The contact model was based on a surface energy formulation weighted by the roughness model developed by Pullen and Williamson (1972). It introduced a novel aspect, the development of adhesion under the effect of external mechanical loads, which is consistent with the cold compaction process. This model was then applied to predict the mesoscopic properties of a packing of spheres, i.e. its response to mechanical stresses of any type, in particular strongly deviatoric stress paths. Such a method intends to be a help toward the development of an efficient continuum model for the modelling of the powder compaction process.

Análise dinâmica de uma laje aliviada biaxial submetida a ações humanas

Abstract The bi-axial hollow slab is the result of applying a technology that removes concrete from the least useful region and replaces it with hollow plastic spheres. This technique leads to material economy and self-weight saving, without considerable inertial loss, enabling larger and more flexible spans. Consequently, these spans are vulnerable to unwanted vibrations and dynamic acceleration caused by external actions, such as movements produced by human activity. This way, understanding the dynamic behavior of this technology and confronting it with normative limits on the project phase is essential for a good performance in the serviceability limit state, bringing comfort to the user. This paper studies the dynamic behavior of a bi-axial hollow slab submitted to human actions, such as jumping, dancing, clapping, moving the body, and moving and clapping at the same time. For that, this work made a numerical model of the structure and applied dynamic actions to it. The numerical results show that, for most of the actions, normative limits are satisfied, but the slab presents excessive accelerations in the case of jumping and dancing.

Development of a Microfluidic Device for Blood Cells Extraction in Liquid Biopsy

This project aims to produce a microfluidic device capable of separating 6 μm and 20 μm diameters particles by inertial sorting. This Lab-on-Chip (LoC) was designed with a trapezoidal cross-section for better fluid control and effective particle manipulation at the microscopic level, as demonstrated by COMSOL simulations. The device was manufactured on a substrate of Polymethyl Methacrylate (PMMA) by femtosecond laser technology and then assembled using an innovative geometry-preserving Isopropyl alcohol-based procedure. The LoC was test with spherical plastic microparticles of two diameters (6 μm and 20 μm) suspended in distilled water. The separation efficiencies were (98.2 ± 1.6) % for 20 μm diameter particles and (70.0 ± 1.8) % for 6 μm diameter particles in good agreement with the simulation results. Finally, after a microfluidic channels’ acetone vapors treatment, the device demonstrated a good ability to separate biological particles (Red Blood Cells) at different concentrations (20%, 30%, 40%, 50%) in a PBS buffer.

Anti-biofouling performance and microbial communities of an integrated fixed-film activated sludge membrane bioreactor with a fibrous carrier material: Pilot-scale demonstration

Widespread use of membrane bioreactors for high-performance wastewater treatment depends on the prevention of biofouling during membrane filtration, which can reduce operating costs. Biofouling is usually prevented using mechanical and chemical membrane treatment methods, which can be time-consuming and expensive. In this study, we developed bio-capsules as a fluidizing carrier material in an integrated fixed-film activated sludge membrane bioreactor (IFAS-MBR). The bio-capsules were prepared from moniliform polyvinylidene chloride fibrous balls enclosed in a spherical plastic basket, and could harbor protozoa and metazoa. A pilot-scale anoxic–oxic IFAS-MBR system with a total volume of 132 m3 was operated to remove organic carbon and nitrogen from municipal wastewater at a high permeate flux (0.84 m3/m2/day). The efficacy of the bio-capsules and the prokaryotic/eukaryotic community structures in the system were investigated. After operation for 1 year, the system demonstrated stable removal of organic carbon (76.0 % ± 15.5 % as total organic carbon, 93.1 ± 5.3 % as BOD, and 88.5 ± 5.2 % as CODMn) and nitrogen (71.3 % ± 9.3 %) despite fluctuations in the influent concentrations. Increases in transmembrane pressure (TMP) were retarded from its increase rates from 0.56 kPa/day to 0.149–0.224 kPa/day by the bio-capsules, and the TMP was kept constant at around 20 kPa throughout the operational period. High-throughput sequencing of 16S rRNA gene amplicons showed that the prokaryotic family Pirellulaceae was metabolically active and correlated with the TMP. According to the 18S rRNA gene sequencing, the eukaryotic metazoan Bdelloidea was more abundant in the bio-capsules than in activated sludge, which was supported by microscopic observations. These results suggest that the application of bio-capsules prevents increases in the TMP by harboring the procaryotes and eukaryotes responsible for biofouling mitigation in the IFAS-MBR system.

Investigation on electric properties of 0.57(Bi0.8La0.2)FeO3‐0.43PbTiO3 porous ceramics prepared by burnable plastic sphere method

AbstractIn this study, 0.57(Bi0.8La0.2)FeO3‐0.43PbTiO3 (BLF‐PT) porous ceramics were fabricated by the burnable plastic sphere method using polymethyl methacrylate (PMMA) as a pore forming agent. X‐ray diffraction results reveal that BLF‐PT porous ceramics mixed with tetragonal and rhombohedral phases display the single perovskite structure, changing little for different porosities. Scanning electron microscope images show that porosity of BLF‐PT ceramics increases with the increase of PMMA content with average grain size of 3.2–3.5 μm. Different from the continuous decrease of dielectric constant εr and remnant polarization Pr, piezoelectric constant d33 of BLF‐PT porous ceramics increases initially but then drops with the increase of porosity that reaches to the maximum of 230 pC/N at porosity of 8.5 vol.%. The abnormal enhancement of piezoelectric property is attributed to the unique three‐dimensional grid porous ceramic skeleton and uniformly distributed grain size. Moreover, acoustic impedance Z of BLF‐PT porous ceramic is 11.2 MRayls at porosity of 24.3 vol.% comparing with that of 17.7 MRayls for bulk ceramics, which reduces by 58%. BLF‐PT porous ceramics at lower porosity with enhanced piezoelectric and acoustic matching performances have a great potential in the fields of underwater acoustic transducers and medical ultrasonic diagnosis.

Influence of plastic aggregate geometry on strength properties of cement-stabilized macadam

In order to improve the toughness and flexibility of cement-stabilized macadam and inhibit crack formation and propagation, the influence of plastic aggregate geometry on the strength properties of cement-stabilized macadam is studied. The surface roughness of plastic aggregate was designed into Ra 12.5 and Ra 25. When the content of plastic coarse aggregate was gradually increased from 4 to 8%, 12%, 16%, 20%, and 24%, the compressive strength, splitting strength, and the tensile-compression ratio of the cement-stabilized macadam made of aggregate with rough surface texture were found higher than those of aggregate with smooth surface texture. The rough cylindrical, spherical, spindle, and dumbbell-shaped plastic coarse aggregates were designed and prepared for testing. The test results showed the maximum compressive strength, splitting strength, and tensile-compression ratio of cement-stabilized macadam with the dumbbell-shaped plastic coarse aggregate. The tensile-compression ratio increased by 15.2% compared to natural aggregate cement-stabilized macadam. The results show that under the same conditions, the plastic aggregate with different geometry can improve the compressive and splitting strengths of cement-stabilized macadam and significantly improve the toughness and flexibility, with dumbbell-shaped plastic coarse aggregate having the greatest improvement, especially compared with natural aggregate cement-stabilized crushed stone. This research provides insights for improving pavement engineering quality and new ideas for utilizing waste plastics.

Reduced area approach for predicting punching shear resistance of biaxial hollow slabs with openings

Due to the inclusion of hollow plastic spheres in bubbled slab systems, the shear resistance is greatly reduced. Also, the existence of the opening in the vicinity of columns takes away part of the concrete responsible for resisting shear forces and unbalanced moments, which in turn further reduces the punching shear capacity of the slab-column connection. In this study, experimental and theoretical investigations had been carried out on bubbled slabs with 2000 × 2000 × 230 mm dimensions. The investigated parameters were the size, position, distance of opening relative to the column stub, and the location of bubbles relative to the critical shear perimeter. A new calculation approach for determining punching shear resistance for bubbled slabs was developed. The proposed modification for calculating the effective critical perimeter showed an appropriate range of agreement of the punching shear strength, which is calculated by the methods adopted by (ACI 318, Eurocode 2, BS 8110, and AS 3600) codes, in comparison to the experimental data. The average ratios of the test results to the calculated punching shear capacity determined according to the proposed approach are between 1.007 and 1.417 with a standard deviation of 0.039–0.186 and a coefficient of variation of 0.038–0.131.

Preparation, characterization and biocompatibility of calcium peroxide-loaded polycaprolactone microparticles.

To explore the physicochemical characteristics and biocompatibility of calcium peroxide (CPO)-loaded polycaprolactone (PCL) microparticle. The CPO/PCL particles were prepared. The morphology and elemental distribution of CPO, PCL and CPO/PCL particles were observed with scanning electron microscopy and energy dispersive spectroscopy, respectively. Rat adipose mesenchymal stem cells were isolated and treated with different concentrations (0.10%, 0.25%, 0.50%, 1.00%) of CPO or CPO/PCL particles. The mesenchymal stem cells were cultured in normal media or osteogenic differentiation media under the hypoxia/normoxia conditions, and the amount of released O2 and H2O2 after CPO/PCL treatment were detected. The gene expressions of alkaline phosphatase (ALP), Runt-associated transcription factor 2 (RUNX2), osteopontin (OPN) and osteocalcin (OCN) were detected by realtime RT-PCR. SD rats were subcutaneously injected with 1.00% CPO/PCL particles and the pathological changes and infiltration of immune cells were observed with HE staining and immunohistochemistry at day 7 and day 14 after injection. Scanning electron microscope showed that CPO particles had a polygonal structure, PCL particles were in a small spherical plastic particle state, and CPO/PCL particles had a block-like crystal structure. Energy dispersive spectroscopy revealed that PCL particles showed no calcium mapping, while CPO/PCL particles showed obvious and uniform calcium mapping. The concentrations of O2 and H2O2 released by CPO/PCL particles were lower than those of CPO group, and the oxygen release time was longer. The expressions of Alp, Runx2, Ocn and Opn increased with the higher content of CPO/PCL particles under hypoxia in osteogenic differentiation culture and normal culture, and the induction was more obvious under osteogenic differentiation conditions (all P<0.05). HE staining results showed that the muscle tissue fibers around the injection site were scattered and disorderly distributed, with varying sizes and thicknesses at day 7 after particle injection. Significant vascular congestion, widened gaps, mild interstitial congestion, local edema, inflammatory cell infiltration, and large area vacuolization were observed in some tissues of rats. At day 14 after microparticle injection, the muscle tissue around the injection site and the tissue fibers at the microparticle implantation site were arranged neatly, and the gap size was not thickened, the vascular congestion, local inflammatory cell infiltration, and vacuolization were significantly improved compared with those at day 7. The immunohistochemical staining results showed that the expressions of CD3 and CD68 positive cells significantly increased in the surrounding muscle tissue, and were densely distributed in a large area at day 7 after particle injection. At day 14 of microparticle injection, the numbers of CD3 and CD68 positive cells in peripheral muscle tissue and tissue at the site of particle implantation were lower than those at day 7 (all P<0.01). CPO/PCL particles have good oxygen release activity, low damage to tissue, and excellent biocompatibility.

130 Exposures to Airborne Human-Respirable Microplastic Particles

Abstract Plastics and their breakdown products, specifically microplastics, are ubiquitously present in the environment from a variety of sources. Analysis of air samples has also revealed the presence of fragmented, spherical, and fibrous plastic particles in a wide range of sizes from the submicrometer scale up to tens of micrometers in length and diameter. However, few studies have addressed the health consequences associated with exposures to airborne microplastics, specifically whether they can enter the respiratory tract, where they will deposit, and how polymer chemistry and morphology are linked to adverse health outcomes. Whether microplastics have unique toxicological properties in comparison to other particle types is also unknown. Our work has sought to address critical questions about the inhalability and respirability of microplastics in indoor and outdoor air via particle size-restricted sampling coupled with morphological assessment and estimation of plastic burdens via Nile red staining. We found Nile red-positive (putative plastic) particles in air samples from indoor environments (office, campus/household laundry rooms, 3-D printing/engineering laboratory), most of which appeared to have a fragment-like morphology. These particles represented ~1% of the total collected sample in terms of number. Importantly, these particles were also found when sampling was restricted to the human-respirable fraction (&amp;lt;4 micrometers in aerodynamic diameter), suggesting that they can reach the gas exchange region. Ongoing work is focused on identifying the polymeric species in these air samples, their distribution across particle size classes, and whether indoor and outdoor microplastic particles are similar in terms of morphology, size, and chemistry.

Investigation of spherical and non-spherical binary particles flow characteristics in a discharge hopper

The particulate flow characteristics of granular particles including mung beans, wooden spheres, wooden cylinders, wooden cubic, plastic spheres, plastic cylinders, and their binary mixtures in a flat bottom hopper were studied experimentally using high-speed high-resolution camera recordings. An image processing method based on the color threshold was developed to calculate the area ratio for binary mixtures. The mass discharge rates, the residue inclination angles, and the changes in edge height and center height with time were also investigated. In addition, the effects of different initial packing patterns on the particulate flow, mixing and segregation behaviors were analyzed and compared. It is interesting to find that the shape of particles and the initial binary particle packing patterns have significant effects on the discharging characteristics. The results of this study provide helpful guidance for industrial applications and provide experiment data for computational model validation.

Acoustic radiation force and torque on an object near a penetrable interface or impedance boundary

An analytical approach for calculating radiation force and torque on a sphere or spheroid near a rigid or pressure release boundary due to an arbitrary incident acoustic field was developed recently by the authors [Proc. Meet. Acoust. 48, 045004 (2022)]. In that approach, the linear scattering problem is solved using the method of images along with expansions of the acoustic fields in spherical or spheroidal wave functions. The expansion coefficients can then be substituted into an existing expression to obtain the radiation force and torque on the object. In the present work, the aforementioned theory is extended to include penetrable interfaces and impedance boundaries using an approximation of the interfacial boundary conditions. For fluid-fluid interfaces, the object can be placed on either side of the interface with respect to the incident field. This approximate analytical approach is computationally efficient and compares well with the results from an independent finite element model. In addition, an experiment was conducted with a plastic sphere submerged in water and positioned near a boundary. Results from the experiment are discussed in relation to the analytical model. [BES is supported by the ARL:UT Chester M. McKinney Graduate Fellowship in Acoustics.]

Effects of Shape on Interaction Dynamics of Tetrahedral Nanoplastics and the Cell Membrane.

Cellular uptake of nanoplastics is instrumental in their environmental accumulation and transfer to humans through the food chain. Despite extensive studies using spherical plastic nanoparticles, the influence of the morphological characteristics of environmentally released nanoplastics is understudied. Using dissipative particle dynamics simulations, we modeled the interactions between a cell membrane and hydrophobic nanotetrahedra, which feature high shape anisotropy and large surface curvature seen for environmental nanoplastics. We observe robust uptake of nanotetrahedra with sharp vertices and edges by the lipid membrane. Two local energy minimum configurations of nanotetrahedra embedded in the membrane bilayer were identified for particles of large sizes. Further analysis of particle dynamics within the membrane shows that the two interaction states exhibit distinct translational and rotational dynamics in the directions normal and parallel to the plane of the membrane. The membrane confinement significantly arrests the out-of-plane motion, resulting in caged translation and subdiffusive rotation. While the in-plane diffusion remains Brownian, we find that the translational and rotational modes decouple from each other as the particle size increases. The rotational diffusion decreases by a greater extent compared to the translational diffusion, deviating from the continuum theory predictions. These results provide fundamental insights into the shape effect on the nanoparticle dynamics in crowded lipid membranes.

Enlarged Head Pressure-Dispersed Anchor Cable for Foundation Pit Engineering Purposes

The enlarged head pressure-dispersed anchor cable is a new type of anchor cable, and the enlarged head of the anchor solid is a multisegment body with variable cross section. Compared with the traditional tension type anchor cable structure, the stress mode of the anchor solid is changed from tensile stress to compressive stress, which is more reasonable. The development process of the plastic zone of the soil around the enlarged head anchor solid is verified by a simulation method. The spherical plastic zone space formed at the enlarged head anchorage end is conducive to the load transfer between the anchor solid and the surrounding soil and reduces the displacement of the anchor solid in the soil. In this pursuit, the present study examines the force mechanism of the enlarged head pressure-dispersed anchor cable. Subsequently, taking an actual project as an example, the anchoring capacity of the enlarged head pressure-dispersed anchor cable and enlarged head tension-type anchor cable was analyzed and compared using FLAC3D software. The results indicate that the support effect of the enlarged head pressure-dispersed anchor cable was better than that of the enlarged head tension anchor cable.

Settling of Mesoplastics in an Open-Channel Flow

Pollution of water by plastic contaminants has received increasing attention, owing to its negative effects on ecosystems. Small plastic particles propagate in water and can travel long distances from the source of pollution. In order to research the settling motion of particles in water flow, a small-scale experiment was conducted, whereby spherical plastic particles of varying diameters were released in an open-channel flow. Three approaches were investigated to numerically simulate the motion of particles. The numerical simulation results were compared and validated with experimental data. The presented methods allow for deeper insight into particle motion in fluid flow and could be extended to a larger scale to predict the propagation of mesoplastics in natural environments.

Diffusion and Velocity Correlations of the Phase Transitions in a System of Macroscopic Rolling Spheres.

We study an air-fluidized granular monolayer composed of plastic spheres which roll on a metallic grid. The air current is adjusted so that the spheres never lose contact with the grid and so that the dynamics may be regarded as pseudo two dimensional (or two dimensional, if the effects of the sphere rolling are not taken into account). We find two surprising continuous transitions, both of them displaying two coexisting phases. Moreover, in all the cases, we found the coexisting phases display a strong energy non-equipartition. In the first transition, at a weak fluidization, a glass phase coexists with a disordered fluid-like phase. In the second transition, a hexagonal crystal coexists with the fluid phase. We analyze, for these two-phase systems, the specific diffusive properties of each phase, as well as the velocity correlations. Surprisingly, we find a glass phase at a very low packing fraction and for a wide range of granular temperatures. Both phases are also characterized by strong anticorrelated velocities upon a collision. Thus, the dynamics observed for this quasi two-dimensional system unveil phase transitions with peculiar properties, very different from the predicted behavior in well-know theories for their equilibrium counterparts.

Inverse Method for Noninvasive Material Discrimination with Multienergy X-Ray Radiography

Active x-ray inspections have great potential for noninvasive detection of illicit materials. Dual-energy x-ray radiography, in particular, has been used to determine material composition by utilizing the energy-dependence of the x-ray attenuation coefficients. However, current implementations of this method are limited in their ability to determine the material composition of composite objects. Here we present an inverse algorithm that uses multienergy x-ray radiography data to noninvasively reconstruct the contents of a container. A critical feature of the current contribution is that material identification can be performed using conventional detectors and x-ray spectra with different endpoint energies produced by varying nothing more than the tube voltage. Adaptive regularization is used to increase the accuracy of material estimations from multienergy data sets. The utility of these methods is demonstrated with experimentally acquired radiographs obtained using a tunable x-ray source that produces spectra with endpoint energies of 100--450 keV. The object inspected is a scale model of a nuclear materials storage container composed of three-dimensional printed plastic and stainless-steel spheres inside a thin-walled steel container. Reconstructions of the steel sphere thicknesses are within a root-mean-square error of 0.37 cm.

A novel floating compound based on a plastic sphere coated with tin titanate for the removal of the herbicide fomesafen

A tin titanate (SnTiO3) composite was synthesized by hydrothermal method (TSn) then impregnated with RhB dye (TSn@RhB powders). This composite was coated on a spheric plastic support from short life daily products with floatable capability (TSn@RhB/PP). The novel composite and synthesized powder were characterized by SEM, XRD and XPS. The SEM images revealed that the powders had an average particle size of 50 nm. Phases related to rutile and SnO2 present in other tin titanates were shown by the XRD analysis. The powders and composite were evaluated in the removal of the fomesafen molecule, which is an herbicide widely used in a variety of crops, by changing the initial pollutant concentration, sorbent dosage and initial pH. The best removal percentages (92 and over 80%) were achieved by slurry and floatable composite systems, respectively, with initial concentration of 10 mg/L of this pesticide. Similarly, experiments with different initial pH and initial dosage of this contaminant (20 ppm) were conducted. Maximal adsorption percentages of 82 and 81% were reached with neutral and acid solutions, respectively. The TOC analysis demonstrated that solutions with higher initial concentration of this herbicide (20 ppm instead of 10 ppm) favored the removal process. The XPS and FTIR analysis revealed that the pollutant could be removed by the effect of electrostatic and electronic attraction between fomesafen and the TSn@RhB composite. The use of practical coating materials and this novel floatable composite as adsorbent material is a promising alternative in the remediation of contaminated agricultural water and other environmental applications.

Development of an x-ray radiography platform to study laser-direct-drive energy coupling at the National Ignition Facility.

A platform has been developed to study laser-direct-drive energy coupling at the National Ignition Facility (NIF) using a plastic sphere target irradiated in a polar-direct-drive geometry to launch a spherically converging shock wave. To diagnose this system evolution, eight NIF laser beams are directed onto a curved Cu foil to generate Heα line emission at a photon energy of 8.4keV. These x rays are collected by a 100-ps gated x-ray imager in the opposing port to produce temporally gated radiographs. The platform is capable of acquiring images during and after the laser drive launches the shock wave. A backlighter profile is fit to the radiographs, and the resulting transmission images are Abel inverted to infer radial density profiles of the shock front and to track its temporal evolution. The measurements provide experimental shock trajectories and radial density profiles that are compared to 2D radiation-hydrodynamic simulations using cross-beam energy transfer and nonlocal heat-transport models.