An Experimental Evaluation of Resistive Defects and Different Testing Solutions in Low-Power Back-Biased SRAM Cells

This paper compares different types of resistive defects that may occur inside low-power SRAM cells, focusing on their impact on device operation. Notwithstanding the continuous evolution of SRAM device integration, manufacturing processes continue to be very sensitive to production faults, giving rise to defects that can be modeled as resistances, especially for devices designed to work in low-power modes. This work analyzes this type of resistive defect that may impair the device functionalities in subtle ways, depending on the defect characteristics and values that may not be directly or easily detectable by traditional test methods. We analyze each defect in terms of the possible effects inside the SRAM cell, its impact on power consumption, and provide guidelines for selecting the best test methods.

Optimization of Aggregate Production Circuit through Modeling of Crusher Operation

The paper concerns investigation of the effect of impact crusher operation on selected qualitative characteristics of mineral aggregate products. Qualitative characteristics of crushing products in terms of size reduction ratio and fine particles contents were analyzed from the point of view of operational parameters of the impact crusher. An investigative program was carried out on a plant scale and two primary parameters of the impactor were analyzed: velocity of the crusher rotor and the width of the outlet gap. The models of the crushing device operation were built separately for each type of the tested material, as well as for general conditions.

Silica: Ubiquitous Poison of Metal Oxide Interfaces

In this review, we consider electrochemical applications, broadly conceived, in which both ions and electrons play key roles in device operation and where exchange of oxygen between the gas and...

Experimental Study on the Thermal Effect according to the Distance around a Hydrogen Jet Flame

In this study, the safe distance in the case of a hydrogen vehicle fire was analyzed according to the temperature distribution around a hydrogen gas jet flame formed by the thermally activated pressure relief device operation of a hydrogen storage container. The experiment was conducted while 70 MPa hydrogen gas was released from a 1.8-mm-diameter nozzle to a 1.8- × 1.8 m fire-resistant structure wall for distances of 2 and 4 m between the nozzle output and the wall. To analyze the temperature around the hydrogen gas jet flame, five fire-fighting heat-protective hood test samples, certified by the Korea Fire Institute, and temperature sensors were installed every 1 m from the center of the jet flame in the vertical direction to the direction of the flame. In the experiment, the temperature around the jet flame was measured to observe the safe distance for firefighters. The results show that the safe distances at 70°C or less, which is harmless to firefighters, were 5 m without a heat-protective hood and 3 m with a heat-protective hood. In addition, it was confirmed that the direction of the jet flame and blocking by obstacles affect the safe distance during fire-fighting and rescue activities by firefighters.

Implementation of a mobile spectrometer using a near infrared MEMS Fabry–Pérot interferometer sensor

Miniaturised MEMS-based Fabry-Pérot interferometer (FPI) spectral sensors allow the design of compact spectrometers in the near infrared (NIR) range. These small-size instruments can be used for quality control of alimentation products, sorting of plastics and fabrics in respect to the material composition or defining genuineness of goods. This article describes design details and achieved results in development of an inexpensive user friendly hand-held NIR spectrometer incorporating a MEMS-FPI sensor with the spectral range of 1550–1850 nm. Implemented electronic circuitry as well as the optical configuration of the device are discussed, used electronic components and the background for the choice of the light source are presented. Furthermore, the associated software for device operation and data visualisation is described. Achieved technical parameters of the device are discussed and illustrated by examples of acquired spectra. Shared experience in operating a MEMS-FPI sensor could be especially useful for designers targeting low-cost instruments for use by general public.

Materials degradation in non-thermal plasma generators by corona discharge

Atmospheric corona discharge devices are being studied as innovative systems for cooling, sterilization, and propulsion, in several industrial fields, from robotics to medical devices, from drones to space applications. However, their industrial scale implementation still requires additional understanding of several complex phenomena, such as corrosion, degradation, and fatigue behaviour, which may affect final system performance. This study focuses on the corrosive behaviour of wires that perform as a high-voltage electrode subject to DC positive corona discharge in atmospheric air. The experiments demonstrate that the non-thermal plasma process promotes the growth of the oxidative films and modifies the physicochemical properties of the materials chosen as corona electrodes, hence affecting device operation. Surfaces exposed to this non-thermal plasma are electrically characterized by negative exponential decay of time-depend power and analysed with SEM. Implications on performance are analysed and discussed.

Correlating Time Series Signals and Event Logs in Embedded Systems

In many embedded systems, we face the problem of correlating signals characterising device operation (e.g., performance parameters, anomalies) with events describing internal device activities. This leads to the investigation of two types of data: time series, representing signal periodic samples in a background of noise, and sporadic event logs. The correlation process must take into account clock inconsistencies between the data acquisition and monitored devices, which provide time series signals and event logs, respectively. The idea of the presented solution is to classify event logs based on the introduced similarity metric and deriving their distribution in time. The identified event log sequences are matched with time intervals corresponding to specified sample patterns (objects) in the registered signal time series. The matching (correlation) process involves iterative time offset adjustment. The paper presents original algorithms to investigate correlation problems using the object-oriented data models corresponding to two monitoring sources. The effectiveness of this approach has been verified in power consumption analysis using real data collected from the developed Holter device. It is quite universal and can be easily adapted to other device optimisation problems.

Contact Angle Tuning of Copper Microporous Structures

Two-phase, capillary-fed cooling devices are appealing thermal management technologies due to their potential for high heat transfer performance and ease of system-level integration. While existing evaporative wicking structures such as copper inverse opals (CIOs) and copper wire meshes (CWMs) have shown promise for achieving target heat dissipation rates of 100 Wcm−2 or greater, the reliability of these structures for long-term device operation and optimal capillary-driven boiling performance has not received much attention. To ensure proper functionality of the evaporator wick, the microporous copper structures must retain a hydrophilic contact angle during device operation. Surface oxidation of the copper is a critical degradation mechanism that must be addressed to preserve the integrity of the wick. In this study, we systematically investigate the contact angle change of untreated copper and various copper oxides under different conditions. To avoid the formation of hydrophobic Cu2O, we pre-oxidize the copper micro porous wick to form hydrophilic cupric oxide CuO and study the effect of various thermal and chemical oxidation recipes on the hydrophilicity and morphology of the resulting structures. A chemical oxidation formula is implemented for the creation of a stable superhydrophilic surface at a low temperature (70°C) for copper inverse opals (CIOs) (5 μm pore size) and copper wire meshes (CWMs) (76 μm pore opening). The recipe has been optimized to create nano CuO needles with a length of < 100 nm and keep the necks (∼1 μm diameter) open for better capillary wicking of the working fluid. The findings of this study potentially benefit the development of copper-based capillary-fed cooling devices.

Research into the Dynamic Characteristics of the Planetary Cob­Separating Device

In the article, the authors propose a methodological approach to calculating the planetary cob-separating device used in corn harvesters and specialized headers. The dynamic characteristics of the planetary cob-separating device operation were investigated. The authors found out that the machine dynamics research problems are rather diverse due to the complexity of the dynamic processes occurring in them. The theoretical research methods prove to be of particular importance, since they make it possible to define the laws of machine unit motion, even at the stage of designing the planetary cob-separating device. (Research purpose) To propose a method for calculating the main kinematic and dynamic parameters of the vertical cob-separating device operation. (Materials and methods) The authors studied the methodological approaches and mathematical tools used to determine the main kinematic and dynamic parameters of the vertical cob-separating device operation; examined the scheme of a single-drum planetary cob-separating device in a corn harvester and built a differential equation of motion. (Results and discussion) After a step-by-step mathematical calculation with the use of the proposed methodological approach to studying the dynamic characteristics arising during the planetary cob-separating device operation, the following equations were obtained: starting the device at idle; starting the device with a load; feeding stems after starting the device; sudden interruption of the supply. When conducting the laboratory studies, it was determined that the cob-separating device showed the greatest effect at an angular speed of the drum within the range of 52.1-62.2 radians per second. (Conclusions) The authors considered four modes of the cob-separating device operation in a corn harvester and obtained the equations for them. The authors created a diagram of the vertical cob-separating device and proposed a methodological approach and an algorithm for calculating the main dynamic and kinematic indicators of its operation.