Combat Capabilities Development Command Soldier Center

Precision motion control systems are frequently challenged by exogenous disturbances and plant uncertainties, which compromise tracking accuracy and operational stability. To address these issues, the extended state observer (ESO) has been developed to estimate both system states and disturbances in real time. However, conventional ESOs rely on an integral-based mechanism, necessitating a high observer bandwidth to handle rapidly varying disturbances. This, in turn, increases noise sensitivity and reduces stability margins. In this article, we introduce a novel error compensation mechanism that dynamically minimizes the estimation errors inherent in traditional ESOs, thus eliminating the need for a high observer bandwidth. Furthermore, we propose a time delay controller, leveraging historical input–output data to mitigate residual disturbances and plant variations. Experimental results validate the efficacy of our approach: settling time is reduced from 49.81 (conventional ADRC) to 2.74 ms (the proposed method), while disturbance convergence time decreases from 49.94 to 2.41 ms. These results underscore its superiority in high-precision applications that require robustness against disturbances and uncertainties.

SPEs towards the detection of arsenic with a focus on electrode modifications to enhance sensitivity and selectivity.

Interactions between polymers and metal-organic frameworks (MOFs) are a critical determinant of composite performance, yet methods to probe these interactions are generally indirect and ensemble averaging. Here, we present single-particle Langmuir isotherm testing (SPLIT), an atomic force microscope (AFM)-based approach that quantifies polymer adsorption onto the surface of a single MOF particle on an AFM probe. After immersing the MOF-tipped probe in a polymer solution, the adhesion force between the polymer-coated MOF and a reference surface is measured under ambient conditions and found to reversibly vary with polymer concentration analogously to a Langmuir isotherm. This process allows us to compute thermodynamic properties including MOF-polymer binding energies. Repeating SPLIT with different polymer molecular weights and in different solvents shows that this method also provides insight into Flory-Huggins interaction parameters and polymer self-entanglement. Finally, we find that SPLIT measurements can guide the design of mixed-matrix membranes (MMM) as they provide an estimate of polymer concentrations that lead to MOF aggregation. Collectively, this work shows that SPLIT can provide unique information about MOF-polymer interactions using only a single MOF particle with direct relevance to composite design.

We report on an induced circular dichroism in a structurally symmetric plasmonic array operating in the extraordinary optical transmission regime and its readout in optical rectification current, as well as in the optical transmission intensity-angle spectrum. The spin-momentum locking mechanism between the incident wave and the surface plasmon polariton (SPP) is the driving mechanism underlying the induced symmetry breaking and handedness. A great sensitivity to the sample orientation and rotation as well as to light polarization is found in the induced dichroism over certain angular ranges, along with the switching of its handedness. Analytic and computational models show that these phenomena correspond to the selective excitations of SPP resonances that can be tailored with the mesoscopic structural design for applications in vector sensing.

A decline in dissolved oxygen (DO) levels in many waterbodies have been observed in the last few decades. While a well-established technology for DO monitoring exists, it is rather expensive and requires user training to use. Here, we propose a simple, user-friendly, and disposable capillary flow-driven microfluidic device for colorimetric DO determination. The device is constructed with a transparent PET film, double-sided adhesive, and glass microfiber with immobilized reagents in such a way that the sample is taken by dipping the device in the analyzed water to yield the results. Modified Winkler colorimetric assay has been employed to transform oxygen into colored species. The limit of detection of the developed device was 1.7 ppm. Field applicability assessment was performed to ensure that the devices are not susceptible to interference and that measurements can be performed in various environmental conditions by untrained users. The developed devices were validated with freshwater samples from various waterbodies as well as with aquarium water, demonstrating high accuracy. The findings presented here open possibilities to deploy these sensors for citizen-based water quality monitoring campaigns.

Fast, portable, and reliable detection of chemical and biological compounds is an important challenge in many safety and healthcare applications. Chemical sensors based on photonic crystals that use protein-catalyzed capture (PCC) agents as molecular sensors are promising tools for the portable detection of chemical and biological compounds. We present the development and deployment of a high-throughput virtual screening protocol to computationally identify PCC candidates that maximize the binding sensitivity and selectivity for fentanyl. The approach integrates enhanced sampling molecular dynamics free-energy calculations, Gaussian process regression surrogate models, and Bayesian optimization to efficiently navigate the design space of over 1 million PCC candidates, resolve the sensitivity-selectivity Pareto frontier, and identify the top-performing PCC candidates. We analyze the molecular interactions between our top candidates and fentanyl target to propose design rules for high-performance PCC agents to be used for experimental testing and, ultimately, incorporation into next-generation hydrogel-nanoparticle-based chemical sensing devices.

BackgroundCranial electrotherapy stimulation (CES) is a low-intensity, pulsed neuromodulation technique widely marketed for reducing stress and anxiety. Despite its popularity, empirical evidence for its efficacy remains mixed, with few studies employing rigorous controls, standardized protocols, and repeated CES exposures.ObjectiveTo evaluate whether repeated CES sessions can attenuate physiological, biochemical, cognitive, and affective responses to an acute laboratory stressor.MethodsA double-blind, randomized, placebo-controlled clinical trial was conducted with 46 healthy participants (27 military personnel, 19 civilians). Participants were randomized to receive either active CES (250–500 μA at 0.5Hz, individualized intensity) or sham stimulation for 20 sessions over approximately four weeks. At baseline and follow-up visits, participants underwent acute stress induction using torso shock; measures included physiological (heart rate, heart rate variability, respiration rate, pupil diameter), biochemical (salivary alpha-amylase, cortisol), cognitive (spatial orientation, recognition memory, decision-making), and affective (State-Trait Anxiety Inventory) indices.ResultsStress induction reliably elevated sympathetic-adrenal medulla (SAM) and hypothalamic-pituitary-adrenal (HPA) markers as well as subjective anxiety. However, across nearly all outcomes, active CES did not differ significantly from sham, nor were there interactions with session (baseline vs. follow-up). No meaningful group differences were observed in stress recovery, self-reported anxiety, or stress-related cognitive performance.ConclusionsThese predominantly null findings challenge prevailing mechanistic accounts of CES and suggest limited efficacy in buffering acute stress responses in healthy, neurotypical individuals. Further controlled trials are needed to explore alternative parameters, populations, and neurophysiological endpoints to better understand CES’s therapeutic potential.Clinical trial registrationhttps://clinicaltrials.gov/, identifier NCT06034496.

Soldiers are often required to carry heavy external loads over multiple days, which may degrade physical performance. We investigated the effects of repeated load carriage bouts on indirect markers of exercise‐induced muscle damage, liver enzymes, and oxygen‐carrying capacity in active‐duty infantrymen. Fourteen male soldiers (age = 24.6 ± 1.1 y; BMI = 25.7 ± 0.7 kg/m2) underwent a 5‐day protocol, consisting of baseline/familiarization, 3 load carriage bouts, and a recovery day. There were reductions in maximal voluntary contraction strength (p < 0.05), with the knee flexors and trunk extensors showing the greatest declines. Each load carriage bout produced an inflammatory response, including increases in leukocyte subtypes (neutrophils and monocytes) and monocyte chemoattractant protein‐1 (p < 0.05). At the end of the protocol, serum liver enzymes were elevated, and erythrocytes and hematocrit were lower than baseline (p < 0.05). In addition, greater circulating leukocytes at baseline predicted lower knee and trunk torque during recovery. Repeated bouts of load carriage reduce muscle strength and cause inflammation consistent with exercise‐induced muscle damage, alter liver function tests, and decrease oxygen‐carrying capacity in male soldiers, which could compromise readiness for prolonged and/or intense military operations.