China
Africa
Explore chapters and articles related to this topic
Utility Companies and Energy Supply
Published in Clive Beggs, Energy: Management, Supply and Conservation, 2010
Some utility companies meter their customers in kW and kWh rather than kVA and kVAh. At school we are taught that electrical power (measured in watts) is the product of voltage (measured in volts) and current (measured in amps). So at first sight there appears to be no difference between kW and kVA. There is, however, a subtle and very important difference between the two. If an electric current is passed through a reactive load, such as a fluorescent lamp fitting or an induction motor, the current will become out of phase with the voltage and lag behind it. This subject is discussed at length in Chapter 14, so here it suffices to say that reactive loads consume more power than is usefully used. Therefore, a reactive load such as an induction motor will draw a larger current than would be anticipated by its useful power rating. Consequently, if a utility company meters its customers in kW, then it must levy an additional reactive power charge in kVAh. This ensures that the utility is paid for all the power it supplies to the site, and not penalized for the customer’s poor power factor.
The Electronics of Microphones and Loudspeakers
Published in Michael Filimowicz, Foundations in Sound Design for Embedded Media, 2019
Electricity is defined by its current and voltage. You can think of current as how many electrons are flowing and voltage as how excited the electrons are. Current is measured in amps. Voltage is measured in volts. When we multiply the volts and amps of an electric circuit together, the result, measured in watts, is power, the ability to do work. (We’ll discuss watts later in the section on power amplifiers.)
Basic Circuit Analysis
Published in Kevin Robinson, Practical Audio Electronics, 2020
Current is measured in amperes (often shortened to amps). The terms amperage or ampage are sometimes encountered, usually referring to the amount of current a particular device can be expected to draw under normal conditions or the amount of current which a device can handle before failing (e.g. What is the ampage of the fuse in that plug?).
Formulation of zwitter-ionic terpolymeric hydrogels and their comprehensive rheological investigation
Published in Journal of Dispersion Science and Technology, 2023
Muhammad Irfan, Luqman Ali Shah, Abbas Khan, Muhammad Farooq, Mohib Ullah, Muhammad Ismail
The rheograms for ZHG-02 hydrogels are represented in Figure 6 which signify the behavior of ZHG-02 hydrogels. The short-range behavior of the materials is characterized by higher frequencies and is subjugated by a mutable response when bend energy is higher compared to dissipated energy (G′ > G′′). In contrast to that, the long-standing presentation is symbolized by small frequencies and is ruled by a viscous response (G′ ˂ G′′). The crossover frequency point where (G′=G′′) recognizes the changeover between liquid-like and solid-like actions. The inverse of crossover frequency is the relaxation time which is the time for materials to adapt applied stresses or deformations. The curves revealed dominating viscous behavior over elastic in low angular frequency range at all temperatures, but at higher frequencies the elastic behavior prevailed. With improved concentration of AMPS in ZHG-02 hydrogels, both the moduli increased with growing angular frequency but the crossover point lifted to lower frequencies. The shifting of crossover point from higher to lower frequency is the realistic and supporting evidence of more prevailing elastic nature over viscous behavior of the hydrogels. The relaxation time calculated shows an increase from 0.1956s to 0.251 s indicating the enhancement in elastic character with increase in temperature which is due to loss of water content from 3D matrix cause an increase in the elastic nature. Similar kinds of results were also shown in literature which strengthened our findings.[26]
From the Desk of the Editor-in-Chief
Published in IETE Journal of Education, 2022
The fourth paper by P V Ananda Mohan entitled “On the Effect of Operational Amplifier Gain-Bandwidth Product on the Performance of Basic Building Blocks” starts with modeling of the op-amp frequency response and presents the problems created by finite bandwidth of the op-amps on various circuits like amplifiers, summers, integrators and differentiators. It surveys the state-of-the-art of understanding about the effect of opamp bandwidth. Teaching analysis of basic circuits to the students, taking into account the effect of finite bandwidth of the op-amp, from the beginning, is believed to quickly apprise them of various design issues, which they may encounter in practical usage. Further, taking advantage of the non-ideality of the op-amp to come up with designs with the least number of components and the least amount of power consumption is also looked at.
A difunctional Pluronic®127-based in situ formed injectable thermogels as prolonged and controlled curcumin depot, fabrication, in vitro characterization and in vivo safety evaluation
Published in Journal of Biomaterials Science, Polymer Edition, 2021
Samiullah Khan, Naveed Akhtar, Muhammad Usman Minhas, Hassan Shah, Kifayat Ullah Khan, Raghu Raj Singh Thakur
The mechanical stability of injectable hydrogels at body temperature is defined by change of (G′) and (G″) values with frequency variation. In our experiments, the values of G′ and G″ were evaluated as a function of frequency variation between 0.01 and 50 Hz under controlled strain of 1%. It was found that G′ was found greater than G″ indicating the stable state of the injectable hydrogel formulations at body temperature. It was concluded that chemically grafted poly(PF127-g-AMPS) in situ depot hydrogels can provide prolong drug release owing to their stable structure at physiologic conditions. Figure 3(D,E) indicate the change of G′ and G″ as function of variable frequency for chemically grafted poly(PF127-g-AMPS) gel formulations.