A Reconfigurable Cold-Startup SSHI Rectifier with 4X Lower Input Amplitude Requirement for Piezoelectric Energy Harvesting

Synchronized switch harvesting on inductor (SSHI) is an efficient active rectifier to extract energy generated from piezoelectric transducer in piezoelectric energy harvesting system. Unlike passive rectifiers, SSHI rectifiers require a power supply to drive synchronized switches. Unfortunately, there is no stable supply when the system starts...

A PV-assisted 10-mV Startup Boost Converter for Thermoelectric Energy Harvesting

This paper presents a boost converter for thermo-electric energy harvesting with photovoltaic (PV)-assisted startup. The converter employs a new two-phase startup architecture and the PV cell is used in the first phase to provide an initial high voltage for startup. This high voltage drives the boost converter to charge a startup capacitor,...

Mapping the knowledge domain of soft computing applications for emergency evacuation studies: A scientometric analysis and critical review

Emergency evacuation is viewed as a common strategy adopted during the disaster preparedness stage of evacuation to ensure the safety of potentially affected populations. In emergency evacuation studies, soft computing approaches and methodologies have been widely used to support effective decision-making, providing robust and low-cost solutions...

VAL: Volume and Access Pattern Leakage-Abuse Attack with Leaked Documents

Searchable Encryption schemes provide secure search over encrypted databases while allowing admitted information leakages. Generally, the leakages can be categorized into access and volume pattern. In most existing SE schemes, these leakages are caused by practical designs but are considered an acceptable price to achieve high search...

No-Directional and Backward-Leak Uni-Directional Updatable Encryption Are Equivalent

Updatable encryption (UE) enables the cloud server to update the previously sourced encrypted data to a new key with only an update token received from the client. Two interesting works have been proposed to clarify the relationships among various UE security notions. Jiang (ASIACRYPT 2020) proved the equivalence of every security notion in...

Super Tough and Spontaneous Water-Assisted Autonomous Self-Healing Elastomer for Underwater Wearable Electronics

Self-healing soft electronic material composition is crucial to sustain the device long-term durability. The fabrication of self-healing soft electronics exposed to high moisture environment is a significant challenge that has yet to be fully achieved. This paper presents the novel concept of a water-assisted room-temperature autonomous self...

Effect of metakaolin on the autogenous shrinkage of alkali-activated slag-fly ash paste

The high autogenous shrinkage of alkali-activated materials made from slag and fly ash is recognised as a major drawback with regard to the use as construction materials. In this study, metakaolin was introduced into the alkali-activated slag-fly ash (AASF) paste to mitigate the autogenous shrinkage. The shrinkage mitigation mechanism of...

Your Smart Contracts Are Not Secure: Investigating Arbitrageurs and Oracle Manipulators in Ethereum

Smart contracts on Ethereum enable billions of dollars to be transacted in a decentralized, transparent and trustless environment. However, adversaries lie await in the Dark Forest, waiting to exploit any and all smart contract vulnerabilities in order to extract profits from unsuspecting victims in this new financial system. As the...

Fluidization dynamics of cohesive Geldart B particles. Part I: X-ray tomography analysis

Due to the presence of inter-particle cohesive force, cohesive particles reveal totally different fluidization behaviors as compared to the non-cohesive system. This paper studies the fluidization dynamics of Geldart B particles with varying thermal-induced cohesive forces. Multi-source X-ray tomography was applied to reconstruct 3D temporal...

A numerical Bayesian-calibrated characterization method for multiscale prepreg preforming simulations with tension-shear coupling

Carbon fiber reinforced plastics (CFRPs) are attracting growing attention in industry because of their enhanced properties. Preforming of thermoset carbon fiber prepregs is one of the most common production techniques of CFRPs. To simulate preforming, several computational methods have been developed. Most of these methods, however, obtain...

Fluidization dynamics of cohesive Geldart B particles. Part II: Pressure fluctuation analysis

The increase of inter-particle cohesive force greatly changes the fluidization dynamics, finally leading to the partial or complete failure of fluidization. However, few studies concern such transition process. This paper investigates the fluidization dynamics of Geldart B particles with a wide-range of cohesive force by analyzing the in-bed...

Effects of Thermal Reflowing Stress on Mechanical Properties of Novel SMT-SREKs

A novel silicone rubber elastic key (SREK) is proposed in this paper for surface mounting technology (SMT) applications. Effects of thermal reflowing stress on the mechanical properties of SMT-SREKs are investigated. The manufactured SMT-SREKs, which underwent various reflowing conditions in advance, are subjected to pressing force and...

Current and future trends in topology optimization for additive manufacturing

Manufacturing-oriented topology optimization has been extensively studied the past two decades, in particular for the conventional manufacturing methods, for example, machining and injection molding or casting. Both design and manufacturing engineers have benefited from these efforts because of the close-to-optimal and friendly-to-manufacture...

Color Shift Modeling of Light-Emitting Diode Lamps in Step-Loaded Stress Testing

The color coordinate shift of light-emitting diode (LED) lamps is investigated by running three stress-loaded testing methods, namely step-up stress accelerated degradation testing, step-down stress accelerated degradation testing, and constant stress accelerated degradation testing. A power model is proposed as the statistical model of the...

First-principles study of the effect of functional groups on polyaniline backbone

We present a first-principles density functional theory study focused on how the chemical and electronic properties of polyaniline are adjusted by introducing suitable substituents on a polymer backbone. Analyses of the obtained energy barriers, reaction energies and minimum energy paths indicate that the chemical reactivity of the polyaniline...

Luminescence of Ce3+ at two different sites in ?-Sr2P2O7 under vacuum ultraviolet-UV and x-ray excitation

A series of Ce3+ doped ?-Sr2?2xCexNaxP2O7 phosphor compounds has been prepared using a high-temperature solid-state reaction technique. The luminescence properties under vacuum ultraviolet-UV and x-ray excitation were studied. Luminescence spectra reveal three UV-emitting peaks at about 310, 330, and 350 nm from which we conclude that Ce3+...