Reproducibility Distinguishability and Correlation of Fireball and Shockwave Dynamics in Explosive Munitions Detonations

The classification of battlespace detonations, specifically the determination of munitions type and size using temporal and spectral features of infrared emissions, is a particularly challenging problem. The intense infrared radiation produced by the detonation of high explosives is largely unstudied. Furthermore, the time-varying fireball imagery and spectra are driven by many factors including the type, size and age of the chemical explosive, method of detonation, interaction with the environment, and the casing used to enclose the explosive. To distinguish between conventional military munitions and improvised or enhanced explosives, the current study investigates fireball expansion dynamics using high speed, multi-band imagery. Instruments were deployed to three field tests involving improvised explosives in howitzer shells, simulated surface-to-air missiles, and small caliber muzzle flashes. The rate of shockwave expansion for the improvised explosives was determined from apparent index of refraction variations in the visible imagery. Fits of the data to existing drag and explosive models found in the literature, as well as modifications to these models, showed agreement in the near- and mid-fields (correlation coefficient, r2 \u3e 0.985 for t \u3c 50 msec); the modified models typically predicted the time for the shockwave to arrive a kilometer away to better than 10%; and fit parameters typically had an uncertainty of less than 20%. The shockwave was distinctive (Fisher Ratio, FR \u3e 1) within the first 2-10 milliseconds after detonation, then it decayed to an indistinguishable acoustic wave (coefficient of variation, CV \u3c 0.05). The area profiles of the fireballs were also examined and found to be highly variable, especially after 10 milliseconds (CV \u3e 0.5), regardless of munitions type. Scaling relationships between properties of the explosive (mass, specific energies, and theoretical energies) and detonation areas, characteristic times, and properties of the shockwave were assessed for distinguishing weights and types: Efficiency decreased with mass (FR \u3e 19); early-time Mach number and overpressure were primarily dependent on energy release (FR ~ 1.5-10); fireball area increased cubically with specific energies (r2 ~ 0.3-0.76) but its time of occurrence decreased cubically (r2 ~ 0.4-0.67). The relationship between fireball and shockwave features was fairly independent of variability (r2 ~ 0.5-0.9), indicating that both fireball and shockwave features scale similarly with variability in detonations

Characterization and Discrimination of Large Caliber Gun Blast and Flash Signatures

Two hundred and one firings of three 152 mm howitzer munitions were observed to characterize firing signatures of a large caliber gun. Muzzle blast expansion was observed with high-speed (1600 Hz) optical imagery. The trajectory of the blast front was well approximated by a modified point-blast model described by constant rate of energy deposition. Visible and near-infrared (450 - 850 nm) spectra of secondary combustion were acquired at 0.75 nm spectral resolution and depict strong contaminant emissions including Li, Na, K, Cu, and Ca. The O2 (X-b) absorption band is evident in the blue wing of the potassium D lines and was used for monocular passive ranging accurate to within 4 - 9%. Time-resolved midwave infrared (1800 - 6000 cm-1) spectra were collected at 100 Hz and 32 cm-1 resolution. A low dimensional radiative transfer model was used to characterize plume emissions in terms of area, temperature, soot emissivity, and species concentrations. Combustion emissions have 100 ms duration, 1200 - 1600 K temperature, and are dominated by H2O and CO2. Noncombusting plume emissions last 20 ms, are 850 - 1050 K, and show significant continuum (emissivity 0.36) and CO structure. Munitions were discriminated with 92 - 96% classification accuracy using only 1 - 3 firing signature features

Arrhenius Rate Chemistry-informed Inter-phase Source Terms (ARCIIST)

Currently, in macro-scale hydrocodes designed to simulate explosive material undergoing shock-induced ignition, the state of the art is to use one of numerous reaction burn rate models. These burn models are designed to estimate the bulk chemical reaction rate. Unfortunately, these burn rate models are largely based on empirical data and must be recalibrated for every new material being simulated. We propose that the use of Arrhenius Rate Chemistry-Informed Interphase Source Terms (ARCIIST) in place of empirically derived burn models will improve the accuracy for these computational codes. A reacting chemistry model of this form was developed for the cyclic nitramine RDX by the Naval Research Laboratory (NRL). Initial implementation of ARCIIST has been conducted using the Air Force Research Laboratory’s (AFRL) MPEXS multi-phase continuum hydrocode. In its present form, the bulk reaction rate is based on the destruction rate of RDX from NRL’s chemistry model. Early results using ARCIIST show promise in capturing deflagration to detonation features more accurately in continuum hydrocodes than what was previously achieved using empirically derived burn models

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Do Ultrasound Patterns and Clinical Parameters Inform the Probability of Thyroid Cancer Predicted by Molecular Testing in Nodules with Indeterminate Cytology?

Background: Molecular testing (MT) is commonly used to refine cancer probability in thyroid nodules with indeterminate cytology. Whether or not ultrasound (US) patterns and clinical parameters can further inform the risk of thyroid cancer in nodules predicted to be positive or negative by MT remains unknown. The aim of this study was to test if clinical parameters, including patient age, sex, nodule size (by US), Bethesda category (III, IV, V), US pattern (American Thyroid Association [ATA] vs. American College of Radiology Thyroid Image Reporting and Data System [TI-RADS] systems), radiation exposure, or family history of thyroid cancer can modify the probability of thyroid cancer or noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) predicted by MT. Methods: We studied 257 thyroid nodules in 232 patients from 10 study centers with indeterminate fine needle aspiration cytology and informative MT results using the ThyroSeq v3 genomic classifier (TSv3). Univariate and multivariate logistic regression was used for data analysis. Results: The presence of cancer/NIFTP was associated with positive TSv3 results (odds ratio 61.39, p < 0.0001). On univariate regression, patient sex, age, and Bethesda category were associated with cancer/NIFTP probability (p < 0.05 for each). Although ATA (p = 0.1211) and TI-RADS (p = 0.1359) US categories demonstrated positive trends, neither was significantly associated with cancer/NIFTP probability. A multivariate regression model incorporating the four most informative non-MT covariates (sex, age, Bethesda category, and ATA US pattern; Model No. 1) yielded a C index of 0.653; R2 = 0.108. When TSv3 was added to Model number 1, the C index increased to 0.888; R2 = 0.572. However, age (p = 0.341), Bethesda category (p = 0.272), and ATA US pattern (p = 0.264) were nonsignificant, and other than TSv3 (p < 0.0001), male sex was the only non-MT parameter that potentially contributed to cancer/NIFTP risk (p = 0.095). The simplest and most efficient clinical model (No. 3) incorporated TSv3 and sex (C index = 0.889; R2 = 0.588). Conclusions: In this multicenter study of thyroid nodules with indeterminate cytology and MT, neither the ATA nor TI-RADS US scoring systems further informed the risk of cancer/NIFTP beyond that predicted by TSv3. Although age and Bethesda category were associated with cancer/NIFTP probability on univariate analysis, in sequential nomograms they provided limited incremental value above the high predictive ability of TSv3. Patient sex may contribute to cancer/NIFTP risk in thyroid nodules with indeterminate cytology