Active LC Clamp dv/dt Filter for Voltage Reflection due to Long Cable in Induction Motor Drives

This paper presents an active LC clamped dv/dt filter to mitigate the over voltages appearing across the motor terminals. The over voltages at motor terminal is due to voltage reflection effect of long motor cable connected between high frequency PWM inverter having high dv/dt switching waveforms and ac motor drives. The voltage reflection due to fast switching transients can be reduced by increasing the rise time and fall time of inverter output voltage pulses. The most commonly available mitigating technique is a passive dv/dt filter between inverter and cable.  Since, size, cost and losses of passive LC dv/dt filter is more, an active dv/dt filtering technique is used to reduce over voltage at motor terminals. Active LC clamp filtering technique used here consists of a small LC filter designed for a single motor cable length which can be used for any lengths of cable up to 1000m only by changing the active control of the PWM pulses to achieve the desired voltage slope during voltage transition period. The basic principle of active dv/dt filer used here is to charge and discharge the capacitor in the filter with modified PWM pulses to increase the rise time and fall time of output voltage pulses without any extra devices to handle the transient response of the LC filter. Detailed investigation is carried out by simulation using MATLAB-Simulink software with active control of common LC clamp dv/dt filter suitable for various cable lengths ranging from 100 m to 1000 m. Comparative analysis is done with active dv/dt filter designed with a common LC clamp filter and active LC clamp dv/dt filter designed for various cable lengths and also with diode clamped passive dv/dt filter. The results proves the effectiveness of the active common LC dv/dt filter to mitigate the over voltages at motor terminal for cable lengths up to 1000m

Low Speed Estimation of Sensorless DTC Induction Motor Drive Using MRAS with Neuro Fuzzy Adaptive Controller

This paper presents a closed loop Model Reference Adaptive system (MRAS) observer with artificial intelligent Nuero fuzzy controller (NFC) as the adaptation technique to mitigate the low speed estimation issues and to improvise the performance of the Sensorless Direct Torque Controlled (DTC) Induction Motor Drives (IMD). Rotor flux MRAS and reactive power MRAS with NFC is explored and detailed analysis is carried out for low speed estimation. Comparative analysis between rotor flux MRAS and reactive power MRAS with PI as well as NFC as adaptive controller is performed and results are presented in this paper. The comparative analysis among these four speed estimation methods shows that reactive power MRAS with NFC as adaptation mechanism shows reduced speed estimation error and actual speed error at steady state operating conditions when the drive is subjected to low speed operation. Simulation carried out using MATLAB-Simulink software to validate the performance of the drive especially at low speeds with rated and variable load conditions

Sustainalism: An integrated socio-economic-environmental model to address sustainable development and sustainability

This paper delves into the multifaceted concept of sustainability, covering its evolution, laws, principles, as well as the different domains and challenges related to achieving it in the modern world. Although capitalism, socialism, and communism have been utilized throughout history, their strengths and drawbacks have failed to address sustainable development comprehensively. Therefore, a holistic approach is necessary, which forms the basis for a new development model called sustainalism. This study proposes a new socio-economic theory of sustainalism that prioritizes quality of life, social equity, culture, world peace, social justice, and well-being. This paper outlines the six principles of sustainalism and identifies sustainalists as individuals who embrace these new concepts. This study also explores how to attain sustainalism in the modern world through a sustainable revolution, representing a step toward a sustainable era. In conclusion, this paper summarizes the key points and emphasizes the need for a new approach to sustainalism in the broader sense. The insights provided are valuable for further research on sustainalism and sustainability

Nanocomposite cotton fabrics with in situ formed copper nanoparticles using citrus lemon leaf extract as reducing agent

Nanocomposite cotton fabrics (NCCFs) with in situ formed copper nanoparticles (CuNPs) using aqueous extraction of citrus lemon leaves as reducing agent have been made. The NCCFs have been analyzed by SEM, FTIR, XRD and TGA techniques and antibacterial test. The CuNPS have been roughly spherical in shape with a mean size in the range of 82-114 nm. The OH and C-OH groups of leaf extract has played an important role in the generation of the CuNPs in the NCCFs as established by the FTIR spectral analysis. The XRD analysis has indicated that the formation of CuNPs in NCCFs lowered the crystallinity of NCCFs. The thermal stability of NCCFs has been lowered by the CuNPs. However, the NCCFs with in situ generated CuNPs exhibited higher antibacterial activity against both gram-negative and gram-positive bacteria and hence can be effectively used as antibacterial wound dressing and hospital bed materials

Synthesis of Persea Americana Bio-Oil and Its Spectroscopic Characterization Studies

The present investigation aims to evaluate the feasibility of using Persea americana (Avocado) biodiesel in compression ignition engines. Persea americana bio-oil was extracted through a soxhlet extraction process using n-hexane solvent after careful pre-processing of the feedstocks. Since the Free Fatty Acid content was 1.78% estimated through titration, single stage base-catalyzed transesterification technique was adopted using methanol and sodium hydroxide as catalysts in the molar ratio of 1:6. Gas Chromatography-Mass Spectrometry analysis revealed the presence of Oleic acid in major proportions. The Fourier transform Infra-Red analysis confirmed the presence of carbonyl group ester ions between 722.19 cm-1 and 1460 cm-1. The 13C NMR and 1H NMR studies supported the successful transformation of triglycerides into Fatty Acid Methyl Esters with distinct peaks at 3.369 ppm and 48.147 ppm, respectively

Nanocomposite cotton fabrics with in situ formed copper nanoparticles using citrus lemon leaf extract as reducing agent

760-765Nanocomposite cotton fabrics (NCCFs) with in situ formed copper nanoparticles (CuNPs) using aqueous extraction of citrus lemon leaves as reducing agent have been made. The NCCFs have been analyzed by SEM, FTIR, XRD and TGA techniques and antibacterial test. The CuNPS have been roughly spherical in shape with a mean size in the range of 82-114 nm. The OH and C-OH groups of leaf extract has played an important role in the generation of the CuNPs in the NCCFs as established by the FTIR spectral analysis. The XRD analysis has indicated that the formation of CuNPs in NCCFs lowered the crystallinity of NCCFs. The thermal stability of NCCFs has been lowered by the CuNPs. However, the NCCFs with in situ generated CuNPs exhibited higher antibacterial activity against both gram-negative and gram-positive bacteria and hence can be effectively used as antibacterial wound dressing and hospital bed materials

Forecasting and Inventory Planning for Parts with Intermittent Demand- A Case Study

Forecasting demand and developing inventory strategies for parts with an intermittent demand history presents a formidable challenge. We review the results of efforts to forecast part failures and determine inventory strategies for military aircraft parts. Applications of bootstrapping and Croston's method are summarized and the results contrasted with more traditional time series approaches

A simplified analytical procedure for simultaneous determination of alkylphenol ethoxylates and brominated flame retardants in fish tissue samples from Vaal River, South Africa.

In this study, the concentration of alkylphenol ethoxylates (APEs) and brominated flame retardants (BFRs) were determined in fish samples, Labeo umbratus and Carp, collected from the Vaal River in South Africa. Ultrasonic-assisted extraction technique was used to extract the organic contaminants from fish samples, and the resulting extract was purified by sulphuric acid lipid removal followed by Strata X-cartridge SPE clean-up. The APEs and BFRs were derivatized using heptafluorobutyric anhydride before analysis with GC-MS. In both types of fish samples, lower oligomers of APEs were more abundant than the higher oligomers, while HBCD, BDE99 and PBB101 were the dominant BFRs. The concentrations of these pollutants ranged from 1.061 ng/g lipids (t-BP) in Labeo umbratus to 11.860 ng/g lipids (HBCD) in Carp