scispace - formally typeset
Search or ask a question

Answers from top 17 papers

More filters
Papers (17)Insight
As a result, rear window buffeting noise is more severe than that of front window when one window open, and combination pattern of side windows open can reduce buffeting noise.
Noise attenuation of the new ventilated window design has improved significantly by combine flexible absorber and quarter-wave resonator effects.
For the inverter systems, however, it is highly required to reduce undesirable electromagnetic noise and psychoacoustic noise generated by PWM for variable speed operation.
Proceedings ArticleDOI
15 Nov 1993
20 Citations
The inverter is nonlinear which causes instability problems in some specific working points of the AC machine and it emits acoustical noise due to the switching frequency.
The results showed the acceptance of the indoor noise level made by the ventilated window.
The extra attenuation at the observation points in the optimized window system is almost equivalent to the noise reduction at the error sensor and the frequency range of effective control is up to 390 Hz in the case of a single channel active noise control system.
Simulation and experimental results verify the interaction between AC and DC filters and show that EMI filters can be designed to suppress both AC and DC EMI noise to meet the standard with the proposed EMI filter design method.
This noise and vibration issues are partly influenced by the running conditions of the AC and the effect was significant when the AC was turned on.
In this project inserting an active filter between the inverter and the induction machine reduces the acoustic noise, and in this way the acoustic behavior of an existing drive can be improved without needing to replace components or modifying the drive.
The simulation results show that side window buffeting noise is generated by large scale vortices and in low frequency.
Open accessJournal ArticleDOI
Yitao Liu, Ching-Ming Lai 
25 Jun 2018-Energies
17 Citations
The grid-injected current total harmonics distortion (THD) and electromagnetic interference (EMI) noise must be considered in a transformer-less grid-connected inverter for a more electric aircraft (MEA) system.
Open accessJournal ArticleDOI
Zhihao Fang, Dong Jiang, Yechi Zhang 
27 Sep 2018
28 Citations
Therefore, the combination of an advanced modulation strategy and EMI filter is proposed for suppressing of EMI noise in an inverter.
Therefore, the noise immunity of the inverter is also improved greatly.
Thus, RPWM has been attracting interest as an excellent method for the reduction of acoustic noise in inverter drive systems.
Proceedings ArticleDOI
Peng Xu, Pamela Abshire 
01 Dec 2007
This study provides a detailed understanding of how noise affects the operation of the CMOS inverter at low power supply voltages.
This work makes it possible to design a window with both noise shielding and air flow.
The proposed ac-ac inverter is attractive for low power (up to 250 W) high frequency applications.

See what other people are reading

What is method?
4 answers
A method can be defined in various ways depending on the field of study. In sociology, the term 'method' is used differently by different scholars, reflecting the diverse meanings attributed to it within the discipline. In software engineering, a method encompasses principles, techniques, and tools applied in domain engineering, requirements engineering, and software design, highlighting its role in characterizing methods within this realm. Moreover, in the context of semiconductor integrated circuit testing, a method involves steps like initializing memory circuits, supplying test patterns, capturing output values, and comparing them to expected values, demonstrating a systematic approach to testing integrated circuits. Additionally, a method for determining harmonic components in pulse width modulation inverters involves calculating Fourier coefficients of individual pulses and superimposing them to analyze the entire output signal.
How does SVPWM implementation using VHDL affect the efficiency and performance of a motor driver circuit?
4 answers
Implementing Space Vector Pulse Width Modulation (SVPWM) using VHDL in a motor driver circuit significantly enhances efficiency and performance. SVPWM generates a quasi-circular rotating magnetic field, improving AC motor performance over traditional methods. It reduces harmonic distortion, optimizes voltage utilization, and efficiently responds to load torque variations in permanent magnet synchronous motors. Moreover, SVPWM minimizes switching losses and Total Harmonic Distortion (THD) in multilevel inverters, enhancing system efficiency and output control. By utilizing Hardware Description Language for SVPWM implementation, precise control with multiple reference voltage points per sector is achieved, further refining the motor control system. Overall, SVPWM implementation through VHDL positively impacts motor driver circuit efficiency and performance by optimizing voltage output, reducing losses, and enhancing control capabilities.
Are transient evoked potential recored using clicks or tone bursts?
4 answers
Transient evoked potentials can be recorded using both clicks and tone bursts. Clicks are commonly used stimuli for transient-evoked otoacoustic emissions (TEOAE), while tone bursts have been shown to evoke vestibular-evoked myogenic potentials (VEMPs) effectively. Tone bursts, particularly at specific frequencies like 500 Hz, have demonstrated reliable responses with larger amplitudes and better test-retest reliability compared to clicks. Additionally, toneburst-evoked auditory brainstem responses (ABR) have been utilized to obtain frequency-specific information, especially in difficult-to-test populations, showcasing the potential of tone bursts in assessing auditory processing systems. Therefore, both clicks and tone bursts play crucial roles in recording transient evoked potentials, each offering unique advantages in different auditory and vestibular assessments.
What is the advantages of MAXQDA in qualitative analysis?
5 answers
MAXQDA offers several advantages in qualitative analysis. It provides a platform for deep proteome coverage with improved coefficients of variation in protein quantification, accurate false discovery rate estimates, and hypothesis-free analysis of data-independent acquisition samples. Additionally, MAXQDA allows for algorithmic evaluation of conceptualization in qualitative studies through context-oriented models of coding, enhancing the coherence of analytical work. Furthermore, research shows an increasing trend in the use of qualitative data analysis software like MAXQDA, particularly in health sciences, supporting various research designs and data types, with a focus on data management and analysis. Overall, MAXQDA's capabilities in proteomics and qualitative research make it a valuable tool for researchers seeking in-depth analysis and reliable results.
Are there any potential safety concerns or limitations associated with electro magnetic EMS application in agriculture?
5 answers
The application of electromagnetic fields (EMFs) in agriculture presents potential safety concerns and limitations. Safety issues arise due to the need for safe working conditions for operators managing production involving super high frequency (SHF) electromagnetic fields. Concerns about EMF exposure have led to ongoing debates, with some advocating for more stringent exposure limits based on possible biological effects. However, magnetic water treatment (MWT) techniques offer environmentally friendly benefits in agriculture, with no proven harmful effects reported. Additionally, the use of electromagnetic induction (EMI) systems for soil analysis in precision farming requires careful consideration to avoid mutual interference between devices, complicating data acquisition. Overall, while EMF applications in agriculture show promise, addressing safety concerns and technical challenges is crucial for their successful implementation.
How LLM Use Long Contexts?
5 answers
Large Language Models (LLMs) face limitations with long text due to their context window. To address this, methods like Parallel Context Windows (PCW) have been introduced, allowing off-the-shelf LLMs to handle long contexts without retraining. Another approach, Selective Context, enhances efficiency by filtering less informative content, benefiting tasks like summarization and question answering across various data sources. Moreover, efforts to improve LLMs include enabling them to generate text with citations for factual correctness and verifiability, as seen in the ALCE benchmark, which evaluates fluency, correctness, and citation quality of LLM-generated text. These methods and benchmarks aim to enhance LLM performance in handling long contexts and improving the quality of generated outputs.
What are the LIMITS of ESBL detection methods?
5 answers
The limits of ESBL detection methods include challenges in distinguishing between ESBL-variants and penicillinases, as well as between GES-ESBLs and GES-carbapenemases. Routine phenotypic methods using clavulanate and third-generation cephalosporins may not effectively detect ESBLs in isolates co-producing inhibitor-resistant beta-lactamases like AmpC. Additionally, plasmid-mediated ESBLs, commonly found in Klebsiella species, can hydrolyze broad-spectrum cephalosporins and penicillins but are inactive against certain antibiotics like imipenem. The limitations of ESBL detection methods highlight the need for advanced techniques that can accurately differentiate between various beta-lactamase enzymes and provide comprehensive detection of ESBLs in clinical isolates.
What are the remaining unsolved problems of delta-sigma modulator?
5 answers
The remaining unsolved problems of delta-sigma modulators include issues such as limited noise attenuation in first-order modulators due to low modulator order and 2-level quantizer resolution, noise folding effects at low frequencies in closed-loop continuous time delta-sigma modulation structures, and the need for improved circuit scale reduction and spurious reduction without altering the transfer function in delta-sigma modulators. These challenges highlight the ongoing research efforts to enhance the stability, noise attenuation, dynamic range, and overall performance of delta-sigma modulators in various applications, including power converters and operational amplifiers, to address issues related to process, supply voltage, and temperature variations.
What is relationship between noise annoyance level and noise sensitivity?
5 answers
The relationship between noise annoyance level and noise sensitivity is intricate and multifaceted. Studies have shown that noise sensitivity moderates the association between environmental noise exposure and annoyance, affecting health outcomes. Individuals with higher noise sensitivity tend to experience elevated annoyance levels in response to various noise types, such as road traffic noise and aircraft overflights. Moreover, noise sensitivity has been linked to increased psychological ill-health, especially when exposed to road traffic noise, highlighting its role in influencing subjective responses to noise. Overall, high noise sensitivity can amplify noise annoyance levels and contribute to a poorer subjective health status, emphasizing the importance of considering individual differences in noise sensitivity when assessing the impact of environmental noise on well-being.
Why does the resonant frequency change in an inverter with an LCL filter installed?
5 answers
The resonant frequency in an inverter with an LCL filter can change due to various factors. The LCL filter, although advantageous for better attenuation of inverter switching harmonics, is susceptible to resonance with the grid, potentially causing stability issues in the power system. Grid impedance variations can lead to the drift of the resonant frequency, further impacting system robustness and control performance. To address this, adaptive extremum seeking control (AESC) and extremum seeking control-based resonant frequency estimation schemes have been proposed to estimate and track the resonant frequency online, ensuring system stability and performance. These methods offer low computational complexity, enabling effective resonant frequency estimation without burdening the normal inverter controller operation.
Comparison on levels of occupational noise between authorised service centre and general workshop?
5 answers
A comparison of occupational noise levels between an authorized service center and a general workshop reveals significant differences in exposure and potential impacts. The use of digital signal processing in noise measurement instruments has enhanced measurement capabilities, leading to confusion in reporting values under different standards. Studies on threshold hearing levels of workers exposed to varying noise levels show increased hearing losses with higher noise exposure, particularly at 4000 Hz frequency. Research on work stress in electronic companies highlights higher stress levels in clean workshops compared to ordinary ones, especially among males, indicating a potential correlation with occupational noise levels. This emphasizes the importance of understanding and addressing occupational noise exposure variations between different work environments.