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Topic Review
Current Applications of Membrane Bioreactors
A membrane bioreactor (MBR) can be described as a chamber designed for a biochemical transformation combined with a membrane separation process. The membrane can be used for different purposes inside the bioreactor, such as the addition of a reactant or the selective removal of one of the reaction products. Moreover, membranes can be utilized to retain the biocatalyst or act as the support for the biocatalyst or for the separation of enzymes by size exclusion.
  • 4.9K
  • 21 Oct 2020
Topic Review
Current Aviation Fuel Production
For jet fuel, the aviation industry primarily uses two types of fuel: aviation gasoline and aviation kerosene. Aviation gasoline, also known as AVGAS, is derived from the distillation of crude oil in the range between 30 and 170 °C. AVGAS is normally used in small aircraft, such as private aviation, agricultural, and pilot training. Aviation kerosene is also a petroleum distillation product obtained in the range between 150 and 300 °C. This fuel is more suitable in aircraft engines for energy generation through combustion, used in many commercial and military aircraft.
  • 260
  • 03 Nov 2023
Topic Review
Current Sensing Methods in Power Electronics Applications
A current sensor is a device exploited to measure electric currents, either alternating current (AC) or direct current (DC). These devices are used in various applications, including detecting faults, monitoring performance (for control or prognostics), and detecting changes in system behavior. Power applications employ various current-monitoring products to control, characterize, and monitor the current flow. Current sensors, for example, are used in power lines to measure the flow of the current, for controlling current flow, or detect overcurrent or excess currents.
  • 2.0K
  • 10 Aug 2023
Topic Review
Current Sensing Techniques
In electrical engineering, current sensing is any one of several techniques used to measure electric current. The measurement of current ranges from picoamps to tens of thousands of amperes. The selection of a current sensing method depends on requirements such as magnitude, accuracy, bandwidth, robustness, cost, isolation or size. The current value may be directly displayed by an instrument, or converted to digital form for use by a monitoring or control system. Current sensing techniques include shunt resistor, current transformers and Rogowski coils, magnetic-field based transducers and others.
  • 526
  • 17 Oct 2022
Topic Review
Current Source Inverter Power Converters in Photovoltaic Systems
Grid converters play a central role in renewable energy conversion. Current source inverter (CSI) can play a pivotal role in ensuring the seamless conversion of solar-generated energy with the electricity grid, thereby facilitating stable and reliable integration of solar photovoltaic systems.
  • 544
  • 01 Nov 2023
Topic Review
Current Virtual Inertia Topologies
The use of power electronic inverters leads to the dissociation of sources and loads and lowering the power system inertia. Under power imbalance, this drop causes an elevated rate of change in frequency and frequency divergences, which has a notable impact on the system’s frequency stability. As a result, enhanced control techniques for grid-tied electronic converters are required to secure the power system’s stability and support. The virtual-synchronous generator (VSG) control is used to mimic the dynamics of a rotating synchronous generator and improve the power system’s stability.
  • 1.0K
  • 30 Nov 2022
Topic Review
Current-Source Inverter
This entry addresses the topologies of the single-stage isolated matrix inverters with a grid-side switching stage based on the current source inverter (CSI). These inverters have been proposed for the uninterruptible power supplies, high and low-voltage/power photovoltaic systems, low-power fuel cell, different low- and high-voltage battery and/or electric vehicle chargers, audio amplifiers. The fully controlled switches on both terminals of these converters typically can provide the bidirectional power transfer capability, which is also addressed for most of the topologies. The other advantages include soft-switching of semiconductors and absence of the bulky DC-link capacitor. Average efficiency of today’s isolated matrix inverters is comparable with the two-stage power converters; however, due to absence of DC-link they can provide higher reliability and lower cost.
  • 2.6K
  • 28 Oct 2020
Topic Review Peer Reviewed
Cushion Gas Consideration for Underground Hydrogen Storage
Due to the increasing world population and environmental considerations, there has been a tremendous interest in alternative energy sources. Hydrogen plays a major role as an energy carrier due to its environmentally benign nature. The combustion of hydrogen releases water vapor while it also has a vast industrial application in aerospace, pharmaceutical, and metallurgical industries. Although promising, hydrogen faces storage challenges. Underground hydrogen storage (UHS) presents a promising method of safely storing hydrogen. The selection of the appropriate cushion gas for UHS is a critical aspect of ensuring the safety, efficiency, and reliability of the storage system. Cushion gas plays a pivotal role in maintaining the necessary pressure within the storage reservoir, thereby enabling consistent injection and withdrawal rates of hydrogen. One of the key functions of the cushion gas is to act as a buffer, ensuring that the storage pressure remains within the desired range despite fluctuations in hydrogen demand or supply. This is achieved by alternately expanding and compressing the cushion gas during the injection and withdrawal cycles, thereby effectively regulating the overall pressure dynamics within the storage facility. Furthermore, the choice of cushion gas can have significant implications on the performance and long-term stability of the UHS system. Factors such as compatibility with hydrogen, cost-effectiveness, availability, and environmental impact must be carefully considered when selecting the most suitable cushion gas. The present study provides a comprehensive review of different types of cushion gases commonly used in UHS, including nitrogen, methane, and carbon dioxide. By examining the advantages, limitations, and practical considerations associated with each option, the study aims to offer valuable insights into optimizing the performance and reliability of UHS systems. Ultimately, the successful implementation of UHS hinges not only on technological innovation but also on strategic decisions regarding cushion gas selection and management. By addressing these challenges proactively, stakeholders can unlock the full potential of hydrogen as a clean and sustainable energy carrier, thereby contributing to the global transition towards a low-carbon future.
  • 806
  • 15 May 2024
Topic Review
Customer Shopping Behavior Analysis by RFID Models
Analyzing customer shopping habits in physical stores is crucial for enhancing the retailer–customer relationship and increasing business revenue. Radio-Frequency Identification (RFID) technology has emerged as a solution and has been implemented in physical stores for purposes such as smart trolleys and analyzing customer shopping paths. Additionally, previous research has demonstrated that the phase readings and received signal strength (RSS) of RFID, combined with machine-learning algorithms, can effectively track customer activity within the physical store, including product browsing. Therefore, employing machine learning models for identifying customer behavior inside the store is crucial to enhance the efficiency of customer behavior analysis.
  • 393
  • 18 Dec 2023
Topic Review
Customs Broking
Customs brokerage. Custom brokers may be employed by or affiliated with freight forwarders, independent businesses, or shipping lines, importers, exporters, trade authorities, and customs brokerage firms.
  • 413
  • 11 Nov 2022
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