Silver-Zinc batteries for AUV applications

We present a class of inverse-designed, aperiodic multilayer graphene-based perfect absorbers operating in the mid-infrared spectrum (3–5 μm), a range vital for atmospheric transparency and advanced sensing. Our design leverages a fixed material sequence—graphene, PPSU dielectric spacers, and PbSe layers on a gold substrate—while achieving precise spectral tunability solely through layer thickness variation, enabling absorption peak control in 0.25 μm steps without any change in material composition. This physical tunability allows scalable fabrication of wavelength-specific devices using a single manufacturing process. We further demonstrate electrical switchability by dynamically modulating graphene’s chemical potential (µc from 0 eV to 1 eV), enabling absorption amplitude control and wavelength redshifting without structural alteration. The proposed absorber achieves > 99.9% efficiency using only five graphene layers in a compact ~ 2 μm stack, offering significant advantages in size, weight, power, and cost. Our hybrid micro-genetic inverse design algorithm enables this performance while preserving > 90% absorption at incidence angles up to 52°, supporting broad angular robustness. Extensive simulation and field distribution analyses confirm the role of plasmonic confinement and impedance matching. Additionally, we validate the design’s fabrication tolerance and benchmark its performance against recent state-of-the-art absorbers. By combining advanced inverse design with nanophotonic structures, our work advances the field of mid-infrared absorbers, providing a scalable and efficient platform for next-generation optical devices.

We report the design, fabrication, and characterization of electrochemical microelectromechanical systems (EC-MEMS) devices featuring encapsulated fluid as the basis for transduction. Parylene microstructures, including discrete chambers (square or circular geometry), are utilized as physical transducers for electrochemically mediated liquid impedance transduction of physical phenomenon such as contact and force. Parylene-based EC-MEMS technologies uniquely leverage advantages in size (<; 500 μm diameter), packaging (no hermetic packaging necessary), power (nanowatts to microwatts), and flexibility to address the physical sensing requirements of in vivo applications. Robust EC impedance (EI) sensor responses (up to 20% from base-line) and discrimination of 200-nm chamber deflections were possible using the EI transduction technique. Additional transducer configurations enabling electrolysis-based out-of-plane actuation and biomimetic mechanotransduction in microfluidic channels are also presented.

This report details the development of a microfabricated preconcentrator that functions as a fully integrated chemical extractor-injector for a microscale gas chromatograph (GC). The device enables parts-per-billion detection and quantitative analysis of volatile organic compounds (VOCs) in indoor air with size and power advantages over macro-scale systems. The 44 mm{sup 3} preconcentrator extracts VOCs using highly adsorptive, granular forms of graphitized carbon black and carbon molecular sieves. The micron-sized silicon cavities have integrated heating and temperature sensing allowing low power, yet rapid heating to thermally desorb the collected VOCs (GC injection). The keys to device construction are a new adsorbent-solvent filling technique and solvent-tolerant wafer-level silicon-gold eutectic bonding technology. The product is the first granular adsorbent preconcentrator integrated at the wafer level. Other advantages include exhaustive VOC extraction and injection peak widths an order of magnitude narrower than predecessor prototypes. A mass transfer model, the first for any microscale preconcentrator, is developed to describe both adsorption and desorption behaviors. The physically intuitive model uses implicit and explicit finite differences to numerically solve the required partial differential equations. The model is applied to the adsorption and desorption of decane at various concentrations to extract Langmuir adsorption isotherm parameters from effluent curve measurements where properties are unknown a priori.

Laser-driven (LD) lighting is highly demanded in the next-generation lighting technology owing to its advantages of high power, high brightness and compact size. The laser-phosphor conversion technology has become dominant for LD lighting due to its high luminous efficiency and stable performances. As the core component of this technology, the phosphor conversion materials directly determine the chromatic performances and luminous efficiency of the light source. However, conventional phosphor-silicone encapsulation suffers from low thermal conductivity and is prone to carbonization, which can ultimately lead to devices failure. The ceramic phosphors (CPs) are considered as the most promising candidates for LD lighting owing to their superior thermal conductivity, excellent stability and compositional flexibility. This article shows a systematic overview of recent advances in CPs for LD lighting, along with a critical discussion focusing on different emission wavelengths. Furthermore, it also discusses the current challenges in phosphor materials and provides an outlook on their future applications.

A subwavelength terahertz plasmonic Y-branch switch based on graphene/gold hybrid structure is proposed. By controlling the graphene optical conductivity via modifying its chemical potential through a variable applied voltage, the real and imaginary parts of the effective refractive index of the hybrid structure can be controlled. Numerical results obtained from finite element method simulation show that THz wave incident upon the surface of the proposed structure excite surface plasmon that can propagate across the switching device whose length is subwavelength of the input wavelength. The device simultaneously provides advantages of compact size, low power and appropriate ON/OFF ratio.

A highly sensitive silicon chip microtransducer for air flow and differential pressure sensing applications

Characterization of the analytical capabilities of an atmospheric micro‐plasma device for the detection of nonmetals

The attitude and heading reference system (AHRS), which consists of tri-axial magnetometer, accelerometer, and gyroscope, has been widely adopted for three-dimensional attitude determination in recent years. It provides an economical means of passive navigation that only relies on gravity and geomagnetic fields. However, despite the advantages of small size, low cost, and low power, the magnetometer and accelerometer are susceptible to external disturbances, such as the magnetic interference from nearby ferromagnetic objects and current-carrying conductors, as well as the motional acceleration of the carrier. To eliminate such disturbances, a vector-based parallel structure is introduced for the attitude filter design, which can avoid the mutual interference between gravity and geomagnetic vectors. Meanwhile, an approach to estimate and compensate the external disturbances in real time for magnetometer and accelerometer is also presented. Compared with existing designs, the proposed filter architecture and external disturbance rejection algorithm can feasibly and effectively cooperate with mainstream data fusion techniques, including complementary filter and Kalman filter. According to experiment results, in the case that large and persistent external disturbances exist, the proposed method can improve the accuracy and robustness of attitude estimation, and it outperforms the existing methods such as switching filter and adaptive filter. Furthermore, through the experiments, the critical role of fading factor in handling the external disturbance is revealed.

This paper presents a wideband closed-loop relative adaptive calibration method for digital beamformers in phased array applications. Using an internally distributed and injected additive white Gaussian noise source, we equalized the channels relative to a selected channel before beamforming. This relative injection method has a size, weight, and power (SWaP) advantage compared with an absolute method where a copy of the illumination waveform is used as the reference signal. Measured data from an existing 22-phase-center elemental digital beamformer array were used to evaluate the relative method against existing absolute methods. The channel response was extracted and the bit error rate was evaluated using a simulation test bench. A parametric conceptual design was also performed to evaluate the relative SWaP between the relative and absolute methods. The results show that the relative method is 17.6 times smaller, uses 1.3 times less power, and is 2.4 times lower in cost than the absolute method. The results also show that the relative calibration method can be as effective as an absolute method, given that the injected waveform has a higher signal-to-noise ratio than the ambient scene.

An experimental distributed microcomputer concept has been developed, implemented, and is currently operational at the Naval Air Development Center as a vehicle to investigate distributed processing concepts with respect to replacing larger computers with networks of microprocessors at the subsystem or node level. Major benefits being exploited include increased performance, flexibility, system availability, and survivability, by use of mul­ tiple processing elements with reduced cost, size, weight and power consumption.This paper concentrates on defining the distributed processing concept in terms of con­ trol primitives, variables, and structures and their use in performing a decomposed DFT (Discrete Fourier Transform) application function on a laboratory model. The DFT was chosen as an experimental application to investigate distributed processing concepts because of its highly regular and decomposable structure for concurrent execution. The design assumes interprocessor communications to be anonymous. In this scheme, all processors can access an entire common data base by employing control primitives. Access to selected areas within the common data base is random, enforced by a hardware lock, and determined by task and subtask pointers. This enables the number of processors to be varied in the configura­ tion without any modifications to the control structure. Decompositional elements of the DFT application function in terms of tasks and subtasks, are also described.IntroductionStimulated by the reduced size, weight, power consumption, and cost advantages of micro­ processors, distributed computing is an evolving technology and is the subject of many investigative efforts. 1 The major potential benefits of distributed computing include increased system-wide real time performance, ease of adaptability to integration and change, high system availability, and decreased system vulnerability. The introduction of low cost microprocessor technology now permits experimenting with concepts that were previously restricted to paper studies. In addition, the reduced size, weight, and power advantages of microprocessors enable applications that would otherwise not be financially or technically feasible solutions. Because of these desirable characteristics, microprocessor and distri­ buted computing technologies are very attractive for avionic processing system applications. However, before these technologies can be applied effectively, appropriate expertise and tools must first be in place. In view of this need, this paper describes an experimental autonomous control structure2 that was developed and implemented at the Naval Air Develop­ ment Center on a laboratory model. It consists of a pool of concurrently executing micro­ processors which serves as a vehicle for investigating distributed processing concepts.Functional distribution in avionic processing systemsFuture avionic systems are envisioned as having processing functions distributed over many physical processors, which communicate via a common medium such as the MIL-STD-1553 bus. Typical functions may include navigation, communications, radar, and display. A generic configuration is depicted in Figure 1.SUBSYSTEM 1 SUBSYSTEM 2 SUBSYSTEM N

The capability of FSO point-to-multipoint communications using BridgeComm&#x0027;s Managed Optical Communications Array (MOCA) technology has been presented including a general architecture of the terminal. What is worthy of further investigation are the technical and system operational impacts of a MOCA technology-based design for a specific application, namely for Low Earth Orbit (LEO) satellite constellations. Some of the benefits of MOCA technology have been cited including providing size, weight, operational volume, and power advantages relative to a mechanical gimbal for beam steering. However, there are capabilities extending beyond these parameters. This presentation will investigate the effect of MOCA technology on network management, network routing, and other aspects of the network as well as the satellite itself.

This trade study was conducted as a part of the Orion landing system advanced development project to determine possible terminal descent sensor (TDS) architectures that could be used for a rocket assisted landing system. Several technologies were considered for the Orion TDS including radar, lidar, GPS applications, mechanical sensors, and gamma ray altimetry. A preliminary down selection occurred by comparing each sensor's ability to meet the requirements. The driving requirements included the range of operation, accuracy, and sensor development to a technology readiness level of 6 (TRL-6) by the Orion PDR in June 2008. Additionally, Orion is very mass and volume constrained, so these parameters were weighted heavily. Radar, lidar, and GPS applications all had potential to meet the requirements and were carried on for further analysis. Investigation into GPS led to concerns over potential loss of signal and required ground infrastructure, so GPS was taken out of the trade space. Remaining technologies included a pulse-Doppler radar, FMCW radar, and a hybrid lidar ranger and velocimeter (termed the hybrid lidar). The trade boils down to the maturity and weather robustness of the radar options versus the mass, volume, power, and heat shield blowout port size advantage of the lidar. This trade study did not result in a recommended TDS. The trade of the mass and volume impact versus the development time and cost should be made at a higher level than this particular trade study.