High Energy Materials Research Laboratory

ABSTRACT Pyrotechnic delays are used to provide a time interval between two successive explosive events. The burning performance of delay compositions is evaluated by inverse burn rate (IBR s/cm). At present, several pyrotechnic delay compositions consist of oxidizer, which are toxic. This paper reports a less toxic, green delay composition with a higher IBR value, which provides more delay time. The stoichiometry's effect on density, heat of combustion, particle size and crystallite size of composition, and the effect of all these parameters on IBR and delay time have been studied. Results revealed that (B/BaCrO 4 /NC) composition supported combustion and smooth burning propagation in the range of 3%–10% of boron, with an IBR ranging from 0.22–1.59 s/cm. The (B/BaSO 4 /NC) composition supported combustion with smooth burning propagation in the range of 10%–40% of boron with an inverse burn rate ranging from 0.84–2.04 s/cm. The use of green oxidizer barium sulfate as a replacement for barium chromate in (B/BaCrO 4 /NC) binary delay system significantly increases the IBR and produces more delay time in the same column length hardware.

About 2.2 billion folks across the planet deal with vision impairment, making movement and routine tasks tough. White canes help plenty, yet miss dangers like overhead items, things at chest height, or slick surfaces underfoot. Instead of sticking strictly to tradition, our team explored something smarter using an ESP32 chip as its brain. It uses two HC-SR04 sensors working together - spotting blocks high and low by sending out sound pulses. Moisture detection comes through a touch-based pad that reacts when water changes surface charge nearby. Location tracking? That part runs on a Neo-6M GPS piece, quietly updating position without delay. When tested in real hands, distance readings stayed accurate within plus or minus two centimeters. Cold start included - the GPS found satellites every time, never taking longer than 45 seconds to connect. Power draw got close attention - this whole system works just fine on a regular 3.7V lithium battery holding 3000mAh, lasting about seven and a half hours nonstop before needing more juice. Not stuck inside a lab, we worked alongside community groups supporting people with disabilities, launching hands-on trials across urban areas to watch how it holds up during actual travel routines. Sitting right in the middle - not too simple, not overloaded with tech - it becomes a wallet-friendly tool that boosts sureness for those who are blind or have limited sight when walking new routes

The present study investigates the feasibility of using 3D-printed Acrylonitrile Butadiene Styrene (ABS) and Polylactic Acid (PLA) as propellant grains for hybrid rocket engines. The primary objective is to assess their combustion performance, focusing on regression rate, chamber pressure, and pressure drop across the orifice. The propellant grain is designed using a CAD software and manufactured using 3D printing techniques while taking the standard considerations of a propellant grains in a Hybrid Rocket Propulsion System (HRPS). Materials used for manufacturing of the 3D-printed propellant grain are ABS and PLA. In addition to the advantages of the 3D printing manufacturing technology, both materials exhibit significant reactivity when burned in the presence of an oxidizer. The present study concludes with a demonstration of manufacturing and static testing of the propellant grains for the HRPS. ABS produced a higher regression rate that suggests it is a better fuel for the Hybrid rocket propulsion system. Future studies will explore alternative 3D-printed materials, thrust profile evaluations, and extended-duration burn tests to further optimize fuel grain performance.

Due to the increasing frequency of cyber threats, healthcare institutions face significant security and privacy challenges. Blockchain provides a potential solution to improve safety in these systems. This article presents a distributed application built on the blockchain, designed for IoT-integrated healthcare environments, with a focus on securing and maintaining the integrity of medical certifications. The proposed solution enhances the operational effectiveness and robustness by facilitating the secure creation and management of medical certifications. The framework includes three core functions: authorization, authentication and registration. The model is developed using the Solidity programming language on the Remix platform and performance factors such as throughput, access time, latency and computation time are used to assess its effectiveness. The proposed framework achieves security by integrating blockchain-based immutable storage, encryption mechanisms, and authentication through smart contracts. Devices and medical certifications are validated using a two-step authentication process involving both asymmetric encryption and smart contract-based authorization, minimizing risks such as unauthorized access and data tampering. Many functional features including authentication and authorization processes, are tested and analyzed with regard to deployment efficiency and resource expenditure, which are measured by gas consumption.

This study investigates the influence of displacement rate on the mechanical behaviour of hydroxyl-terminated polybutadiene (HTPB)-based composite solid propellant at room temperature. Uniaxial tensile tests are performed at the displacement rates of 1, 50 and 1000 mm/min where the digital image correlation (DIC) technique is employed for the accurate measurement of deformation and strain fields. The DIC setup included two cameras focusing on the transverse and lateral surfaces of the specimen which enabled the determination of all strain components, allowing for the calculation of Poisson’s ratio and dilatation. It is observed that the nominal strain, determined from cross-head displacement, consistently exceeds DIC-measured strain across all displacement rates. The stress-strain responses exhibit a strong dependence on displacement rates. As the displacement rate increases from 1 to 50 mm/min, the failure strain increases by 41.86%, and the tensile modulus in the linear region rises by 7.07%. Further increasing the displacement rate from 50 to 1000 mm/min results in an additional 9.84% increase in failure strain and a significant 48.2% rise in the tensile modulus in the linear region. Poisson’s ratio decreases non-linearly as longitudinal strain increases across all displacement rates. Dilatation, calculated using the finite strain formula, is initially zero but increases with strain for all displacement rates.