Applied Energetics (United States)

With a view to valorizing local resources, juncus fibers have recently been used as reinforcements in building materials. The aim of this study is to compare their thermophysical and mechanical behavior in adobe with that of coconut fibers, which are generally imported and not available locally. Raw materials were subjected to chemical, geotechnical, mineralogical and microstructural characterization. Different volumetric percentages of the two types of fiber (0%, 10%, 20%) were incorporated into the adobes. The thermal conductivity, apparent density and mechanical strength of the adobes were determined for each sample. The microstructure was analyzed by scanning electron microscopy (SEM). The addition of 20% juncus fibers improves thermal performance by 12.34%, compared with 10.6% for coconut fibers, with a decrease in mechanical strength due to poor fiber–matrix adhesion observed by SEM.

Shaped charges have been pivotal in military and industrial applications for over a century for their ability to penetrate hard targets with remarkable efficiency. A generic 66 mm shaped charge device is widely used as a screening tool to evaluate the performance of new explosive formulations such as high energy and combined effects explosives. This paper presents a comprehensive study on the modeling and analysis of the 66 mm shaped charge experiment, focusing on the critical stages of explosive detonation, jet formation, jet elongation and particulation, as well as target penetration as a function of standoff. A multi-faceted approach is adopted, combining computer simulations, analytic modeling, and experimental data to provide a thorough description of the relevant mechanics. High-fidelity numerical simulations were performed using the Los Alamos National Laboratory (LANL) Eulerian hydrodynamic code PAGOSA. These calculations were used to elucidate the factors influencing jet formation including material strength, equation of state, geometry, and detonation models. Analytic modeling of the jet breakup and penetration mechanics were also used to predict the effects of jet characteristics and standoff on target penetration. The experimental methodology and data reduction procedures are briefly outlined, and modeling predictions are compared to experimental data. • LANL PAGOSA code models liner collapse and jet formation for a 66 mm shaped charge. • Excellent agreement with experimental jet characteristics is demonstrated. • Penetration mechanics calculations performed using mass profiles and jet breakup models. • Predictions assess how charge modifications affect penetration performance.

The aim of this work is to experiment and compare the operation of two solar cookers, namely a parabolic solar cooker and a box solar cooker in order to encourage the population to use solar thermal equipment. For this purpose a parabolic cooker fitted with a mirror as a reflector and a box cooker were created. These two sensors are tested under the same conditions following the international standard procedure for testing solar cookers and reporting performance. Under a solar flux varying between 250 W/m2 and 1009.78 W/m2, the maximum water temperature is 108.87°C and 98.02°C at the parabolic cooker and the box cooker, respectively. The parabolic cooker has a standardized cooking power than the box cooker. The specific boiling time is 0.41 h.m2.Kg-1 and 0.54 h.m2.Kg-1 for the parabolic cooker and the box cooker respectively. The output of the parabolic cooker is higher than the canned one in the morning. The two efficiencies decrease as a function of time and in the evening the efficiency of the parabolic collector becomes lower compared to that of the box cooker. In view of these results, solar cookers can be used in our climate zone to meet certain cooking energy needs.

Laser wakefield acceleration (LWFA) may enable the next generation of TeV-scale lepton colliders. Reaching such energies will likely require multiple LWFA stages to overcome limitations on the energy gain achievable in a single stage. The use of stages, however, introduces challenges such as alignment, adiabatic matching between stages, and a lower average accelerating gradient. Here, we propose a discrete flying focus that can deliver higher energy gain in a single stage, thereby reducing the number of stages required for a target energy. A sequence of laser pulses with staggered focal points and delays drives a plasma wave in which an electron beam experiences a near-constant accelerating gradient over distances beyond those attainable with a conventional pulse. Simulations demonstrate that a discrete flying focus with a total energy of 150 J can transfer 40 GeV per electron to a 50-pC beam in a single 30-cm stage, corresponding to 50 dephasing lengths.

Shock-compressing material samples that are precompressed with diamond-anvil cells (DACs) enables benchmarking equation of state measurements over a wide range of high-pressure conditions, in particular, warm dense matter relevant to planetary science, astrophysics, and inertial confinement fusion. These targets provide optical access to the shocked sample, so optical velocity interferometry and pyrometry are typical diagnostics. We present a scaling for the coupling of the laser drive to the shock pressure in DACs based on over 150 prior experiments that can be used to design future experiments. For initial static pressures ≤ 5 GPa, using a sapphire window mitigates the effect of photoionization compared to diamond windows and allows the measurement of shock pressures up to 1 TPa with optical diagnostics.

A new neutron time-of-flight (nTOF) detector for yield and ion-temperature measurements in deuterium-tritium (DT) implosions was designed, installed, and calibrated on the OMEGA Laser System. This detector was installed at θ = 46.8° from the vertical and φ = 84.9°, previously a region without other detectors, in order to decrease the uncertainty of low-mode asymmetry measurements by six other nTOF detectors. The new nTOF detector uses the "PMT only" concept [Glebov et al., Rev. Sci. Instrum. 92, 013509 (2021)] and consists of a Photek photomultiplier tube (PMT)-110 in a thin aluminum housing. There is no lead shielding in front of the PMT to allow measurements of the x-ray instrument response function of the detector. The detector is installed in the OMEGA H2-port line of sight at 9.3m from the target chamber center in the OMEGA Target Bay and is called the H2 nTOF detector. The H2 nTOF measures DT yields in the 1 × 1013 to 3 × 1014 range and ion temperatures from 2 to 12keV. H2 nTOF reduced the hotspot flow uncertainty in the z-direction from ±10 to ±8 km/s, and the uncertainty in the anisotropic flow axis from σθ = ±26° to ±13° and σφ = ±25° to ±21°. The design details, performance, and calibration results of the H2 nTOF detector in DT implosions on OMEGA will be presented.

Programmed cell death (apoptosis) safeguards tissue homeostasis,and its dysregulation is a hallmark of cancer, neurodegeneration,and immune disorders. Detecting the earliest biochemical signaturesof apoptosis therefore offers a route to sharper diagnosis, real-timetherapy monitoring, and data-driven drug discovery. Electrochemicalbiosensors are uniquely suited to this task because they translatemolecular recognition events into electrical signals that are rapid,miniaturizable, and inherently compatible with point-of-care formats.Yet their clinical translation is still limited by three persistenthurdles: (i) selective recognition in protein-rich or highly variablematrices, (ii) long-term signal stability under continuous operation,and (iii) a lack of unified analytical performance standards thathampers cross-platform benchmarking. This critical review charts themost recent material, biochemical, and microelectronic innovationsthat are beginning to erode these barriers, and identifies emergingstrategiesfrom nanostructured electrode interfaces to signalprocessingthat could propel electrochemical apoptosis sensing from proof-of-conceptprototypes to reliable bedside tools. By aligning unresolved challengeswith promising technological solutions, we aim to guide interdisciplinaryefforts toward next-generation diagnostics capable of real-time apoptosissurveillance in complex biological settings.

In July–August 2024 on the Kola Peninsula, the FENICS-2024 experiment was conducted to generate artificial electromagnetic signals at night, using two power transmission lines as a horizontal radiating antenna. The generator frequency varied discretely from session to session from 1 to 194 Hz with current amplitude from ~150 A at low frequencies to ~40 A at high frequencies. The paper presents the results of the first stage of the experiment when the power transmission line Vykhodnoy—Olenegorsk with a distance between earth electrodes of substances L=84 km was utilized as a radiating antenna. Magnetic stations, located from ~1200 to ~2100 km from the nodal substation, recorded signals with frequencies from 1 to 9 Hz with ~0.3–~6.0 fT/A amplitudes normalized to the emitter current. The observations have shown the promise of the new type of active experiments on creating a probing signal for magnetotelluric sounding over a large area. The observation results will be compared with theoretical models in the subsequent work.