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Oral administration provides a simple and non-invasive approach for drug delivery. However, due to poor absorption and swift enzymatic degradation in the gastrointestinal tract, a wide range of molecules must be parenterally injected to attain required doses and pharmacokinetics. Here we present an orally dosed liquid auto-injector capable of delivering up to 4-mg doses of a bioavailable drug with the rapid pharmacokinetics of an injection, reaching an absolute bioavailability of up to 80% and a maximum plasma drug concentration within 30 min after dosing. This approach improves dosing efficiencies and pharmacokinetics an order of magnitude over our previously designed injector capsules and up to two orders of magnitude over clinically available and preclinical chemical permeation enhancement technologies. We administered the capsules to swine for delivery of clinically relevant doses of four commonly injected medications, including adalimumab, a GLP-1 analog, recombinant human insulin and epinephrine. These multi-day dosing experiments and oral administration in awake animal models support the translational potential of the system. Biologics are delivered by a pill that pricks the stomach wall.

The high-temperature and high-pressure response of magnesium has been investigated through shock-release experiments performed up to shock melting. The longitudinal and bulk sound speeds of Mg are reported along the Hugoniot from 25 to 56 GPa and used to determine the elastic properties and Gr\"uneisen parameter. The hexagonal close-packed (hcp)--body-centered cubic (bcc) phase transition is marked by a reduction in the determined shear wave speed. Thermal softening is observed to begin between 40 and 44 GPa, with incipient melt at 55.5 GPa, in close agreement with previous diffraction measurements under laser shock loading. Examination of the release profiles showed that two different responses were observed, depending on the peak stress. When plotted in a stress-energy phase diagram, the two responses are observed to form separate lines that intersect the static hcp-bcc phase transition and incipient melt. The results indicate that the hcp-bcc transition occurs on the Hugoniot at 28.4 GPa and place the hcp-bcc-liquid triple point \ensuremath{\sim}20 GPa. A multiphase equation of state is developed which places the melt boundary below the previously reported static measurements.

Transit through the carbon liquid phase has significant consequences for the subsequent formation of solid nanocarbon detonation products. We report dynamic measurements of liquid carbon condensation and solidification into nano-onions over ∽200 ns by analysis of time-resolved, small-angle X-ray scattering data acquired during detonation of a hydrogen-free explosive, DNTF (3,4-bis(3-nitrofurazan-4-yl)furoxan). Further, thermochemical modeling predicts a direct liquid to solid graphite phase transition for DNTF products ~200 ns post-detonation. Solid detonation products were collected and characterized by high-resolution electron microscopy to confirm the abundance of carbon nano-onions with an average diameter of ∽10 nm, matching the dynamic measurements. We analyze other carbon-rich explosives by similar methods to systematically explore different regions of the carbon phase diagram traversed during detonation. Our results suggest a potential pathway to the efficient production of carbon nano-onions, while offering insight into the phase transformation kinetics of liquid carbon under extreme pressures and temperatures., Detonation of high explosives can produce many nanocarbon allotropes and morphologies, but the mechanism of formation is challenging to explore. Here the authors observe, by time-resolved small-angle X-ray scattering, a transient liquid phase that precedes the formation of carbon onions.

In this work, we performed 1D plate impact experiments to examine spall responses of electroplated gold samples produced using constant potential (DC plated) and pulsed plating techniques. The spall response of these two types of electroplated samples were compared with that of a wrought gold sample, all of which were shocked to a peak stress of ~37 GPa. Our results show comparable spall strengths of 2 GPa for the electroplated and the wrought gold samples. Spall strength values obtained from our gun experiment are similar to spall strength obtained from explosively driven shock experiments, but they are significantly lower than those reported in laser-driven shock studies on thin gold samples. Overall, our results show that electroplating is a viable method for producing gold samples that have dynamic mechanical properties comparable to those produced by conventional techniques.

Compression-induced solidification has been observed in cerium on nanosecond timescales. A series of experiments was conducted in Sandia National Laboratories' Z Facility in which cerium was shock melted and subsequently shocklessly, or ramp, loaded across the melt line inducing solidification. The signature of solidification manifested in the recovery of material strength and the propagation of waves at the local elastic sound velocity. Density functional theory simulations of cerium along the experimental phase-space path exhibit spontaneous freezing to a tetragonal phase at the same pressure and closely predict the observed physical properties of solid and liquid cerium near melt.

In this work we provide direct evidence of shock-induced melting and associated kinetics in a porous solid (aluminum powder) using time-resolved x-ray diffraction. Unambiguous evidence of melting in 50% porous aluminum (Al) powder samples, shocked to peak pressures between $\ensuremath{\sim}13\text{\ensuremath{-}}19\phantom{\rule{0.16em}{0ex}}\mathrm{GPa}$, was provided by the broadening of the Debye-Scherrer ring corresponding to the (111) peak. Shocked Al powder did not melt completely in any of our experiments within the durations of measurement. Incomplete (partial) melting of the powder, even after several hundreds of nanoseconds of shock loading, provides insights into thermal transport with Al powder particles under high-pressure dynamic loading. Such insights are quite valuable for developing well-constrained melting models and thermodynamic equations of state for porous Al and other porous solids relevant to planetary and materials science.

The dynamic response of structured materials, such as regular lattices, is nontrivial partly due to the interaction of mechanical waves throughout the structure and free surfaces as the material is dynamically compressed. The existence of an elastic precursor wave in additively manufactured lattices was recently shown to match theoretical predictions and simulation results. Following up on this work, we have investigated the behavior of the elastic precursor with propagation distance, impact speed, and impact material. Through a series of gas gun experiments coupled to X-ray phase contrast imaging measurements and complementary simulations, the elastic precursor wavespeed appears to be nearly independent of impact speed and impact material. We observed evidence for the sustained elastic wave propagation through many unit cells at four significantly different impact conditions. We compared these results with direct numerical simulations of the experiments and found good agreement.

Time-resolved x-ray diffraction was used to examine the phase evolution of polycrystalline Mg shocked along the principal Hugoniot to states that span multiple phase boundaries into the liquid. The diffraction data indicate that the hcp-bcc phase boundary lies above 27 GPa, with the hcp-bcc transition occurring within nanoseconds of loading. Experiments at 55 GPa reveal a mixture of bcc and liquid, indicating incipient melt occurring 10--15 GPa lower than previously reported, with complete melting observed at 63 GPa.

In traditional shock physics, the determination of density variations are inferred by applying the standard Rankine- Hugoniot jump conditions although proton radiography allows the direct measurement of density. The reintroduction of the 40-mm powder driven gas gun in 2017 allows us to deliver well characterized shock profiles into a variety of materials. In this particular experiment, we show that the densities obtained agree well with a recently developed two-phase Mie-Gruneisen model for cerium. The model had been tuned using several double shock experiments which showed a slowing down of the shock wave speed. A brief look at the model and comparison of the resulting volume densities determined from the radiographic images. Although there was a low proton transmission through the cerium, we show that in this particular experiment that there is a good agreement between the calculated and the experimental densities.

Mesoscale simulations of a LiF impactor colliding with a PMMA capsule containing aluminum powder (ρ00 = 1.5 g/cc) have been performed to investigate shock-induced melting in porous metals. Impact velocities of 1-2.5 km/s are chosen to coincide with in situ X-ray diffraction experiments, which provide direct evidence of shock-induced melting in aluminum powders. Mesoscale simulations show shock heating within the powder is highly nonuniform and melting remains incomplete over hundreds of nanoseconds behind the shock front despite equilibrium pressure-temperature states from continuum simulations lying above the experimental melt line. Such incomplete melting behavior is consistent with X-ray diffraction data obtained in experiment. For an impact velocity of ∼1 km/s, mesoscale simulations predict re- solidification behind the shock front as high-temperature regions are cooled below the melt line. Reducing the grain size of the powder by a factor of two leads to a reduction in the time required to reach complete melt such that total melting of the powder may be observed experimentally for an impact velocity of 2.42 km/s.

Material strength properties for metals under shock loading conditions were investigated using high-fidelity, ultra-high-speed X-ray diagnostics. High-strain rate Richtmyer-Meshkov instability (RMI) experiments were performed with an explosive powder driven gas gun at the Advanced Photon Source (APS) located at Argonne National Laboratory. Metal targets (copper and aluminum) with a prescribed sinusoidal interface, were studied using photonic Doppler velocimetry (PDV) and X-ray phase contrast imaging (PCI). The metal targets were impacted at velocities up to ~2.25 mm/μs with subsequent maximum strain rates ranging between 107–108 s−1. The instability was recorded using X-ray PCI having a spatial resolution of 2–3 microns with sub-nanosecond exposures. Due to the constructive/destructive interference of X-rays and other challenges with artifacts associated with PCI, edge extraction must be robust against deviations in brightness, contrast, and noise. For the experimental images, a phase congruency feature detection algorithm outputs quantitative descriptors of edges for the metal jet size and shape. Computational hydrocode simulations were used to fit parameters for various strength models, with good agreement. The spatial and temporal resolution of our measurements allow validation and expansion of previously documented literature on these materials.

Dynamic materials properties experiments on Sandia National Laboratories Z Machine require increasingly precise electrical current pulse shaping. In the experiment described here, a copper flyer plate is accelerated from rest to 1,600 m/s over a 40 micron flight gap in 50 ns. This flyer then impacts a cerium sample, shock melting the cerium, before subsequent quasi-isentropic ramping to mega-bar pressures. Through predictive simulations, postdicted analysis, and a new computational tool for characterizing inherent Z Machine timing accuracy, qualitative estimates of pulse controllability and experimental design robustness are arrived upon.

Time-resolved x-ray diffraction (XRD) was used to examine the behavior of Ce under shock loading to stress states up to 22 GPa that span the shock-melt transition. Experiments reported here observed Ce held at a steady state for ∼500 ns prior to being uniaxially released to ambient pressure. Time-resolved XRD shows a constant diffraction pattern over the duration of the steady state with rapid solidification occurring on release. Cerium was found to remain crystalline as Poisson's ratio (ν) increases in the α-phase with incipient melt observed in XRD once ν reaches 0.5. Diffraction results along with sound speed measurements limit melt completion to be between 12 and 14 GPa, significantly lower than previously expected. The XRD results add confidence to previous methods used to define incipient melt and help to define a method to constrain the melt region along the Hugoniot independent of a light source.

The performance of energetic materials subjected to dynamic loading significantly depends on their micro- and meso-scale structural morphology. The geometric versatility offered by additive manufacturing opens new pathways to tailor the performance of these materials. Additively manufactured energetic materials (AMEMs) have a wide range of structural characteristics with a hierarchy of length scales and process-inherent heterogeneities, which are hitherto difficult to precisely control. It is important to understand how these features affect AMEMs’ response under dynamic/shock loading. Therefore, temporally and spatially resolved measurements of both macroscopic behavior and micro- and meso-level processes influencing macroscopic behavior are required. In this paper, we analyze the shock compression response of an AMEM simulant loaded under several impact conditions and orientations. X-ray phase contrast imaging (PCI) is used to track features across the observed shock front and determine the linear shock velocity vs particle velocity equation of state, as well as to quantify the interior deformation fields via digital image correlation (DIC) analyses. Photon Doppler velocimetry is simultaneously used to measure the particle velocities of the specimens, which are consistent with those obtained from x-ray PCI. The DIC analyses provide an assessment of the average strain fields inside the material, showing that the average axial strain depends on the loading intensity and reaches as high as 0.23 for impact velocities up to 1.5 km/s. The overall results demonstrate the utility of x-ray PCI for probing “in-material” equation of state and interior strains associated with dynamic shock compression behavior of the AMEM simulant.

Dynamic compression experiments have proven useful for decades in examining material response at high pressures and providing equation-of-state and other information on numerous phenomena including phase transitions, strength, and kinetics.

The ability to understand and predict the response of matter at extreme conditions requires knowledge of a material’s equation-of-state including the location of phase boundaries, transition kinetics, and the evolution of material strength. Cerium is a material with a complex phase diagram that continues to attract significant scientific interest. Recent dynamic experiments have provided information on the low-pressure γ– α phase transition, sound speed, and Hugoniot data for the higher-pressure α phase, as well as the incipient shock melt transition. Despite these efforts, there are still regions of the phase diagram that are largely unexplored dynamically, including the high-pressure region below the melt boundary. Along a room temperature isotherm, diamond anvil cell data report a transition to the ϵ phase between 13 and 17 GPa. At higher temperatures, similar diamond anvil cell data show significant disagreement regarding the existence, location, and slope of the ϵ-phase boundary. In this work, double-shock loading was used to access the α– ϵ region of the phase diagram to obtain equation-of-state information and to determine the location of the ϵ-phase boundary for shock loading.

Shock compaction response of ∼50% porous aluminum powder, encapsulated in PMMA cylinders and impacted at 0.3–1.7 km/s using 6061-T6 Al impactors, was examined in situ and in real time using a propagation-based X-ray phase contract imaging (PCI) technique capable of providing micron spatial resolution at the Advanced Photon Source. Numerical simulations of the PCI data accurately captured the propagating compaction shock wave in the powder and the deformation of the powder column.

Ceramics are important materials due to their high strength and hardness, particularly in armor systems such as personnel body armor where they are used extensively. Understanding the failure process for these types of systems is key to improving their performance. To better understand the process of failure in ceramic materials subjected to ballistic impacts, we planned and executed reverse ballistic experiments to study material failure during impact on a silicon carbide target. The primary diagnostic tool we used was proton radiography conducted at Los Alamos National Laboratory Neutron Science Center (LANSCE) using their 800 mega-electron-volt (MeV) linear accelerator. Proton radiography at this facility is capable of excellent spatial and temporal resolution with up to 31 frames of data captured with variable frame spacing and gate time. We report and discuss some of the results of these experiments.

During the electrical explosion of bridge-wires and bridge-foils, the metal bridge undergoes rapid resistive-heating. The metal is rapidly expanded through solid, liquid, vapour and plasma phases. This study uses ALEGRA MHD, a Sandia National Laboratory magneto-hydrocode, to predict the formation of these metallic phases during the explosion process and determine the effects of surface heterogeneities on the spatial distribution of these phases. The simulations are compared against x-ray phase contrast radiographs of electrically exploded bridge-foils. From comparison of these data, it is evident that the meso-structure of the metallic foil dominates the explosion process and is something that should be controlled during the manufacturing processes for detonator designs.

Recent advances in diagnostics coupled with synchrotron sources have allowed the in-situ investigation of exploding foil initiators (EFI) during flight. We present the first images of EFIs during flight utilizing x-ray phase contrast imaging at the Advanced Photon Source (APS) located in Argonne National Laboratory. These images have provided the DOE/DoD community with unprecedented images resolving details on the micron scale of the flyer formation, plasma instabilities and in-flight characteristics along with the subsequent interaction with high explosives on the nanosecond time scale. Phase contrast imaging has allowed the ability to make dynamic measurements on the length and time scale necessary to resolve initiator function and provide insight to key design parameters. These efforts have also probed the fundamental physics at “burst” to better understand what burst means in a physical sense, rather than the traditional understanding of burst as a peak in voltage and increase in resistance. This fundamental understanding has led to increased knowledge on the mechanisms of burst and has allowed us to improve our predictive capability through magnetohydrodnamic modeling. This manuscript presents results from several EFI designs along with a look to the future for upcoming work.

The response of particulate materials to impulsive loading includes complex interactions between grains due to fracture and comminution and the presence of interstitial material. The quasi-static strength of saturated powders is related to the concept of “effective stress” in which the fluid stiffens the material response and reduces the shear strength. However, detailed information regarding the effects of saturation under dynamic loading is lacking since static equilibrium between phases cannot be assumed and the interaction becomes more complex. Recent experiments on the IMPULSE (IMPact System for ULtrafast Synchrotron Experiments) capability at the Dynamic Compression Sector (DCS) of the Advanced Photon Source (APS) have captured in-situ X-ray phase-contrast images of shock loaded soda lime glass spheres in dry and saturated conditions. Previous investigations have observed reduction of fragmentation attributed to “cushioning” of an interstitial fluid in impact recovery experiments. The differences between the modes of deformation and compaction are compared with direct numerical simulations showing that the cause of fracture is different. In drained (dry) impact experiments at 300 m/s, the fractures initiate near the contact point between grains. In fully saturated experiments with identical impact conditions, spallation is observed during the incident stress-wave passage in the glass before the H2O has equilibrated.

Understanding the shock response of porous, granular materials is important for many scientific applications. In this work, a propagation-based x-ray phase contrast imaging technique was used to examine the shock compaction response of Ni powder (particle size: 30 and 45 µm), encapsulated in PMMA cylinders, in situ and in real time. The propagating shock wave in the PMMA cylinder and the deformation of the Ni powder column were recorded, but the compaction wave in the Ni powder could not be observed due to insufficient penetration of x-ray photons through the sample. The overall shape of the deformed Ni column downstream of the PMMA shock looked qualitatively similar for both particle sizes: it deformed inward and then outward similar to a converging-diverging nozzle, followed by a ‘mushroom’-like structure at the impact face. A preliminary analysis of our data using shock-polar method provided insight into the observed shock and flow deflection angles at the PMMA/Ni interface, and permitted evaluation of the Ni powder EOS used in this work.

The study of dynamic compression of materials requires high precision spatial and temporal resolution to infer the material state at any given time. In ultra-fast imaging experiments such as those performed at the Dynamic Compression Sector at the Advanced Photon Source, the current CCD frame rate is less than the X-ray pulse rate necessitating that 4 CCDs be used to image a single scintillator screen to obtain the same projection of transmitted or diffracted beam at time intervals synchronized with the X-ray beam. The use of multiple-camera setups is often employed for a variety of reasons including enhancing the temporal resolution through interleaving frames or increasing the number of viewpoints, for example. Physical corrections are made to have each CCD approximately viewing the same field of view, however we present corrections that can be made after the data collection to further refine and be able to compare movements and changes in the sample between independent CCDs. These software corrections enable higher precision and higher fidelity comparison of position changes due to sample deformation. We present a method to correct images (or frames) as a demonstration toward high fidelity displacement measurements in these types of ultra-fast multi-camera setup experiments.

The Photovoltaics for Sustainable Milk for Africa through Refrigeration Technology (PV-SMART) uses direct drive PV for off-grid milk cooling under the USAID Powering Agriculture Energy Grand Challenge Program (PAEGC). The project is implemented by Winrock International and SunDanzer Refrigeration Inc. refrigeration. The PV chillers are direct drive using a dc compressor that chills ice stored in the walls of the refrigeration unit. This eliminates the need for electro-chemical batteries and successfully chills milk to 10°C in 2 hours and 4°C by morning preventing bacteriological growth. Farmers can receive a premium price for providing higher quality, refrigerated evening milk to dairy processors that would otherwise spoil. These PV farm milk chillers are the first of their kind with 80 pilot units deployed in Kenya.