Modal Analysis Method Research Articles

Instabilities in magnetized inhomogeneous dusty plasmas with the effect of recombination

An analytical formalism to understand the impact of various parameters on evolving instabilities in inhomogeneous collisional dusty plasmas is presented here under the effect of recombination. The basic fluid dynamics for electrons and singly charged cold ions is carried out including recombination and collision at constant rate at the surface of dust particles. Dust particles are considered to be static with unperturbed density. Normal mode analysis method has been used along with linear approximation to get perturbed densities (n i1, n e1) which are used along with quasi-neutrality condition to get perturbed potential using Poisson’s equation to obtain dispersion relation. While other authors have detected instabilities in unmagnetized plasmas, here this method has been successfully realized in presence of static magnetic field at various propagation angle and allowed the straightforward calculation of growth rates of observed instability. An extensive study of the unstable modes has been done which are well discriminated and plotted with respect to different plasma parameters like dust charge, dust density, propagation angle, magnetic field, electrostatic potential along with plasma oscillation wavelength to Debye wavelength ratio. We have observed in the said model that the presence of dust particles and propagation angle of applied magnetic field are affecting significantly the growth rate of instability as compared to magnetic field and recombination.

USULAN PENGENDALIAN KUALITAS UNTUK MENGURANGI PRODUK CACAT KEMASAN MINYAK TELON

ABSTRACT PT. Aksamala Adi Andana is a company that produces health products, one of which is "Habbie" telon oil. The increasing demand for products requires companies to maintain and improve the quality of their products. But there are still many defective products that are not in accordance with the standards set by the company. The percentage of telon oil product packaging defects in the January 2020 - December 2020 period reached 5.26%, exceeding the defect tolerance limit of 2%. Types of defects in telon oil product packaging include label sticker defects, cap defects, bottle defects, and folding box defects. Based on the analysis using the Statistical Quality Control (SQC) method, the results of the Pareto diagram show the order of the percentage causes of telon oil product packaging defects, namely sticker label defects (55%), cap defects (21%), bottle defects (13%), and folding box defects. (11%), and the results of the p control chart show that there are 7 of the 12 period points that are outside the control limits with a value of Cp = 0.9489. Based on the analysis using the Failure Mode And Effect Analysis (FMEA) method, the highest RPN value is 192 for the sticker label defect. The Kaizen method is used to generate proposed corrective actions for factors causing defects with the aim of reducing defective products.

A Quantitative Model of International Trade Based on Deep Neural Network.

This paper is an in-depth study of international trade quantification models based on deep neural networks. Based on an in-depth analysis of global trade characteristics, a summary of existing problems, and a comparative analysis of various prediction methods, this paper constructs the ARIMA model, BP neural network (BPNN) model, and deep neural network (DNN) model to make a comprehensive comparison of international trade quantification. The results show that the nonlinear model has a global trade quantification has some advantages over linear models, and the deep model shows better prediction performance than the shallow model. In addition, preprocessing of the time series is considered to improve the prediction accuracy or shorten the model training time. The empirical modal analysis method (EMD) is introduced to decompose the time series into eigenmodal functions (IMFs) of different scales. Then the decomposed IMF series are arranged into a matrix using principal component analysis (PCA) to reduce the dimensionality and extract the data containing the most stock index information features; these features are then input into BPNN and DNN for combined prediction, thus constructing the combined models EMD-PCA-BPNN and EMD-PCA-DNN. Based on Melitz's heterogeneous firm trade theory and its development by Chaney, a quantitative trade model incorporating production heterogeneity is constructed through a multisector extension. This paper adopts a general equilibrium analysis, which makes the modeling process pulse clear. The completed model has high flexibility and scalability, which can be applied to quantitative analysis of various problems.

Quality Control of Frozen Fish Based on Fault Tree Analysis (FTA) and Failure Mode and Effect Analysis (FMEA) Methods

Quality Control of Frozen Fish Based on Fault Tree Analysis (FTA) and Failure Mode and Effect Analysis (FMEA) Methods

Modal analysis and damage localization in plate-type structures via TDD and PE methods based on the data of an integrated highspeed camera system

With the fast development of full-field vibration measurements by combining digital image correlation (DIC) technique with the integrated highspeed camera system, the structural characteristic deflection shapes (CDS’s) can be readily captured, which are sensitive for damage localization. Naturally, the mode shapes are preferred due to their higher signal to noise ratio. However, traditional modal analysis methods are inefficient in processing the large volumes of data that acquired by high-speed camera system for mode shape-based damage localization. Moreover, how to extract the damage features and enhance the damage localization results without the baseline-data of the intact state is another challenging issue. To address these problems, a novel damage localization method is proposed by enhancing the mode shape estimation and optimizing the damage feature extraction. Firstly, the dominant singular vector at each interested resonant frequency is individually evaluated as the mode shapes in the proposed time domain decomposition (TDD) method. Moreover, based on the extracted mode shapes, a pseudo-excitation (PE) method is proposed to reveal the damage locations without baseline-data by examining the perturbation of local dynamic equilibrium. To circumvent the effects of measurement noise on PE method, an adaptive denoising technique is proposed based on Gaussian smoothing. Furthermore, the local contiguity and spatial sparsity of the damage-caused features are harnessed by a hierarchical clustering to optimize the damage localization performance via tuning the scale parameter of Gaussian smoothing. Finally, numerical and experimental studies of crack damaged plates are conducted to validate the feasibility and effectiveness of the proposed mode shape estimation and damage localization methods. During the experiment, the full-field vibration measurements are acquired by using an integrated binocular highspeed camera system. In addition, a comparison study based on benchmark data is carried out to demonstrate the performance and reliability of the proposed damage localization method.

Effect of salt fingers on heat transfer for different non‐uniform concentration profiles in a micropolar liquid

AbstractThis paper discusses the theoretical aspects of the effect of salt fingers on heat transfer for different non‐uniform concentration profiles in a micropolar liquid layer kept between two parallel plates of infinite extent separated by a thin layer, heated and soluted from above. The onset of salt finger convection (convection due to the salt finger process) is studied through the linear stability analysis theory. The system of partial differential equations is solved numerically using the normal mode analysis method and the required solution is found by applying the Galerkin method. The effect of heat transfer and concentration of micropolar liquid is obtained for (i) free–free, (ii) rigid–rigid, and (iii) rigid–free isothermal, permeable with no‐spin boundary conditions. The effect of different micropolar parameters (i.e., coupling parameter, micropolar heat conduction parameter, couple stress parameter, and inertia parameter) has been analyzed on the onset of stationary convection, and the results are depicted graphically. It is shown that different non‐uniform concentration gradients, diffusivity ratio, coupling parameter, and solutal Rayleigh number influence the heat transfer in the system. The phase of concentration flow for different boundary conditions is compared and analyzed.

Wideband and compact filtering power divider based on vertically installed planar structures

In this article, a wideband filtering power divider using vertically installed planar (VIP) circuit is proposed, where three-line coupled structures are introduced to realize filtering responses. The even-odd mode analysis method is applied to assess the electrical performance of the whole structure. The simulated and measured results demonstrate that the proposed design has a wide operation bandwidth (>103%), low insertion loss (<0.6 dB) and good isolation (>15.2 dB). Moreover, the amplitude imbalance and phase imbalance are less than 0.2 dB and 0.5°, respectively.

Design of a compact quint-band bandpass filter using a symmetric dual-mode λ/4 resonator and a pair of inverted F-shaped resonators

In this paper, a compact quint-band microstrip bandpass filter (BPF) based on multiple mode resonating technology is proposed. It is composed of a symmetric dual-mode λ/4 resonator loaded with a shorted stub, two inverted F-shaped resonators, and two pairs of coupling configurations. To miniaturize the filter, the three resonators are bent and cross coupled together. Considering that the BPF has a symmetric structure, the even-odd mode analysis method is employed. On the basis of the simulation, the presented filter was fabricated by using a conventional PCB process with the substrate of Rogers RT/Duroid 5880. The measurement results are consistent well with the simulated data. The measured operating bands are centered at 1.8, 3.5, 4.5, 5.8 and 6.8 GHz, respectively, which are suitable for GSM, WiMAX, 5G, RFID and WiFi6 applications simultaneously. The measured in-band minimal return losses within five passbands are better than 15 dB. Furthermore, the filter exhibits a high selectivity with steep skirt property and the four band-to-band isolations among the five passbands are higher than 27 dB, and the out-of-band rejection is better than 25 dB. The filter’s total dimension occupies only 0.18λg × 0.15λg, where λg represents the free space wavelength corresponding to the center frequency of the lowest passband.

Reliability Evaluation Method of AC/DC Hybrid Distribution Network Considering Voltage Source Converter Restoration Capability and Network Reconfiguration

In the AC/DC hybrid distribution network, non-faulty areas can maintain uninterrupted power supply by adjusting the control mode of the voltage source converter (VSC) after a fault. In addition, the non-faulty areas can also be restored through network reconfiguration. To account for the impact of these two restoration methods on reliability accurately, this article proposed a reliability evaluation method for the AC/DC hybrid distribution network considering VSC restoration capability and network reconfiguration. First, a restoration optimization model of the AC/DC hybrid distribution network considering network reconfiguration and control modes of VSC is established, which can give full play to these two restoration methods while ensuring the radial constraints of the network. Then, the failure mode and effects analysis (FMEA) method is introduced and combined with the restoration optimization model to analyze the impact caused by faults on the network. Among them, the FMEA method is utilized to determine the network topology after fault isolation, and on this basis, the restoration optimization model is solved to obtain the outage time of loads in the network. Finally, the aforementioned work is combined with the sequential Monte Carlo method to evaluate the reliability of the AC/DC hybrid distribution network to adequately simulate the fluctuation characteristics of distributed generation (DG) and load. The case study shows that the proposed method can accurately evaluate the reliability of the AC/DC hybrid distribution network.

Wave propagation in an elastic coaxial hollow cylinder when exposed to thermal heating and external load

This manuscript examines the propagation of waves in a coaxial hollow infinite isotropic cylinder when exposed to a thermal heating source from the outer cylinder. For the mechanical conditions, the inner and outer cylinders are assumed to be displacement-free, in addition to a perfectly welded interface; while an insulation thermal condition is assumed on the interface to prevent the inner cylinder from being heated by an already-heated outer cylinder. Equally, a situation of an external load on the outer cylinder is also examined. As for the methodology, a mixture of the normal mode analysis method and the numerical Laplace integral transform is employed to study the vibrational displacements in the inner and outer cylinders, as well as the temperature field in the outer cylinder. Lastly, certain graphical illustrations associated with low and higher heating periods are demonstrated after considering some physical data and heating sources of practical application.

A highly accurate spectral dynamic stiffness method for efficient broadband modal and dynamic response analysis of membranes assemblies with arbitrary boundary conditions

A highly accurate and efficient spectral dynamic stiffness (SDS) formulation is presented for the broadband dynamic analysis of damped membranes and their assemblies with arbitrary boundary conditions (BCs). First, the general solution satisfying exactly the governing differential equations is derived, and any general BCs are represented by the modified Fourier series (MFS). Second, the modified Fourier coefficients of the force BCs are associated with those of the displacement BCs by eliminating the coefficients in the general solution, where the SDS matrix is formulated. The SDS elements can be assembled through line nodes to model complex geometries and arbitrary BCs can be described. Finally, highly reliable and efficient eigenvalue and dynamic response solution techniques are employed. The performance of the proposed method is illustrated by convergence and efficiency studies. Modal analysis and damped dynamic response analysis are performed for either individual membranes or complex membrane assemblies subjected to general BCs. This method is demonstrated to be more versatile than the classical dynamic stiffness method, and yields highly accurate results with reasonable computational efficiency by comparison with the FEM. Due to these excellent features, this method can serve as a powerful alternative tool for the fluid–structure interaction and broadband vibro-acoustic problems.

Determination to the period of a school building before and after its retrofitting using ambient vibration records

Determining the dynamic parameters of the structures allows us to obtain a substantial amount of information about the state of the building. Recently, the determination of these parameters were performed through Structural Health Monitoring Systems (SHMSs), which are non-destructive methods. In scope of this study, the period values prior to and following the retrofitting of a school building, which are among the dynamic parameters, were examined. The Operational Modal Analysis (OMA) method, which is based on the principle of measuring the responses of ambient effects in the structure in the experimental study, has been utilized. For this purpose, response records taken from the building under the effect of ambient vibration were used. Before and after retrofitting, the records of the building under the effect of ambient vibration were taken from the same locations. 3 sensors were used to record ambient vibrations. The data from these sensors were transferred to a computer by using a data logger. In order to measure and evaluate the responses Enhanced Frequency Domain Decomposition Method (EFDDM) in the frequency domain and Stochastic Subspace Identification Method (SSIM) in the time domain were used. Following the analysis, a comparison of how the period values had changed was conducted.

Scientific challenges in modeling mastication of meat using engineering tools

This paper gives an overview of scientific challenges that may occur while performing modelling meat (as a product) and simulating mastication by using engineering tools. To evaluate these challenges, Failure Mode and Effect Analysis method has been employed to assess six engineering tools often used in analyzing different perspectives of food oral processing. As a result, a risk priority number comprising of severity of the failure, occurrence probability of a failure and difficulty to detect the failure has been calculated. Results show that finite element method and emotion detection are two tools with highest levels of risks. The first method is a known engineering solution used for analyzing different types of materials, but when it comes to meat as a very complex and anisotropic material, risk of inadequate calculations is high. Emotion detection is not so much dependent on meat as a product consumed but on imperfections of software and risk of recognizing false emotions is high. Findings indicate that more research is needed for a more sophisticated use of these engineering tools. Further studies should include other engineering models that simulate meat breakdown during mastication, the role of saliva and jaw movement with the aim to carry out full modelling of mastication of an average meat consumer.

Implementasi Lean Manufacturing untuk Mengurangi Waste pada Produksi Pivot Piece (Studi Kasus PT. Tri Jaya Teknik Karawang)

&lt;p&gt;&lt;em&gt;PT Tri Jaya Teknik Karawang is one of the manufacturing companies engaged in the production of vehicle parts, because its main product is pivot piece. As for other forms of products produced by this company, such as Gongsol and Fuji Seat. This product research at PT Tri Jaya Teknik Karawang will be carried out on one type of Piece Pivot product, because this product is the company's main product, whose regular demand every month is always there and the amount is uncertain. This company has waste in the production line, namely the existence of product defects and lead times. This study aims to determine the types of waste and what factors occur in the production of pivot pieces at PT. Tri Jaya Engineering Karawang. By using the Lean Manufacturing method which begins with creating a Value Stream Mapping (VSM) then performs an analysis using the Failure Mode and Effects Analysis (FMEA) method. It is known that in the production of pivot pieces there are 3 types of waste identified, namely waiting time, unnecessary waste of inventory, and product defects. Proposed improvements to minimize waste in the production of pivot pieces are to carry out regular machine maintenance, create a production flow and provide warnings and evaluations of the performance of production operators.&lt;/em&gt;&lt;/p&gt;

LTCC Bandpass Filter Chips With Controllable Transmission Zeros and Bandwidths Using Stepped-Impedance Stubs

A novel bandpass filter (BPF) chip using stepped-impedance stubs (SISs) embedded in coupled lines (CLs) based on the low-temperature cofired ceramic (LTCC) technology is proposed in this brief. The controllable bandwidth (BW) is mainly realized by the wide range of variable coupling strength of the broadside CLs, and the controllable transmission zeros (TZs) can be generated by SISs to obtain high selectivity. Furthermore, in order to obtain a general design method for the proposed BPF with different BWs, the analytical (closed-form) process based on the even- and odd- mode analysis method is presented. For verification, a prototype for the proposed BPF operating at 3.5 GHz with the 3-dB fractional bandwidth (FBW) of 32.0% is designed, simulated, fabricated, and measured, respectively. Finally, the measured results that are in good agreement with the simulation show good performance of the proposed circuit.

Asymptotic modal analysis application to a cavity-plate system to predict sound transmission loss

The asymptotic modal analysis (AMA) method has previously been developed to predict the high-frequency dynamic response of structural and acoustical systems [Sung et al., Asymptotic Modal Analysis of Structural and Acoustical Systems (Morgan &amp; Claypool Pub., 2021)]. In the AMA method, the dynamic response is obtained as the asymptotic limit of the classical modal analysis (CMA) solution as the averaged response in large frequency bands. In previous work, the AMA method has been applied to uncoupled individual structural and acoustical systems. In the asymptotic limit, the AMA results for individual structural and acoustical systems have been shown to approach the corresponding statistical energy analysis (SEA) results. The AMA method has also previously been applied to a coupled cavity-plate system to predict the high frequency response for piston-like excitation of the plate. In this paper, the AMA method is applied to a cavity–plate system subjected to random excitation of the plate to predict the sound transmission loss into the cavity. The AMA results in the asymptotic limit for the cavity-plate system are shown to approach the corresponding CMA and SEA results. In addition, the AMA method is able to predict the spatial distribution of the plate and cavity responses.

Failure mode effect and criticality analysis of ultrasound device by classification tracking

BackgroundMedical ultrasound device has been more and more widely used in the hospital and Its safety risk is significantly increased when failures occur. However, there is a lack of quantitative risk assessments of different types of failure modes for medical ultrasound device. This study utilizes a failure mode, effect and criticality analysis (FMECA) approach for quantitative risk evaluation of different failure modes for ultrasound devices.MethodsThe 4216 medical ultrasound device failure records at various hospitals were investigated. A failure mode and effect analysis method was developed for the quantitative evaluation of the risks of different failure modes. Visual correlation analysis was conducted for all categories to identify the causes of various failure modes. Based on the severity, occurrence and detectability of the failure causes determined, the risk priority number (RPN) for each failure mode was back-calculated through the obtained tracking diagram.ResultsThe failure modes of unclear images, unable to power on and dark shadows on an image had the highest RPNs. One failure mode could be caused by various factors, and the failure location was not necessarily related to the cause of the failure.ConclusionsThis quantitative approach more accurately evaluated the risks of different failure modes, and the results of the corresponding analysis of failure modes and causes could support the rapid determination of the causes of failures in clinical practice.

Dynamic response and time-variant reliability analysis of an eight-rod shock isolator

The operation of a warship is commonly affected by shock loads in different directions during sailing in a rough sea, which can decrease the precision of the shipboard equipment. To improve the shock resistance performance of the shipboard equipment, an isolator is usually installed to isolate it from the vibration of the ship deck. The paper proposes a method for dynamic response and time-variant reliability analysis of an eight-rod shock isolator (ERSI). ERSI has a novel symmetrical structure, which can improve the utilization of the isolation rods compared with the classical parallel mechanism. The isolator is modeled using Denavit-Hartenberg (D-H) convention and screw theory. Then, Duhamel integral is employed to derive the dynamic response to the isolator after decoupling the governing equation using the modal analysis method. Considering impacts of uncertain factors, this paper also presents a practical method for time-variant reliability analysis of ERSI. Finally, a discussion of the practical example of this method along with a detailed analysis to evaluate the efficiency of the proposed method is presented.

Design and Analysis of a Compact GSM/GPS Dual-Band Bandpass Filter Using a T-Shaped Resonator

This study presents an ultracompact dual-band bandpass filter with controllable transmission zeros based on quarter-wave dual-mode resonator for GSM (global system for mobile communications) and GPS (global positioning system) wireless applications. The filter is made up of two quarter-wave resonators, which help to independently control the passbands. A direct feed resonator creates the first operating band, which serves as a feeding source for the interior resonator and operates at a higher frequency band. Therefore, a pair of transmission zeros can be energized between the two passbands, and high roll-off skirts are obtained. To reduce the size of the entire filter, the two resonators are bent and connected together through a hole in a metal base. The structure is symmetrical in nature, so both frequency bands can be obtained using the even-odd mode analysis method. For GSM applications, the center frequency of the first working band is 850 MHz, while for GPS wireless applications, the center frequency of the second working band is 1.57 GHz. Although there is a feed line (λg is based on a waveguide length of 850 MHz), the filter has been simulated and fabricated for verification, with an ultra-compact size of 0.10 λg × 0.09 λg (0.0095 λg 2). The simulation results and measured results match well, and the theory of the design concept is recognized.

A Detailed FEM Study on the Vibro-acoustic Behaviour of Crash and Splash Musical Cymbals

Advanced numerical simulations, that include modal and frequency response function finite element analysis, frequency domain and time domain finite element method – boundary element method analysis, are performed to study the vibro-acoustic behaviour of crash and splash musical cymbals. The results of the modal analysis agree well with experimental measurements found in literature. The frequency domain and time domain coupled finite – boundary element method simulations, despite their high computational resources and time demands, are used for the crucial comparison of the velocity spectrograms on the cymbal to the radiated sound pressure spectrograms in the air. The computational analysis results show that the splash cymbal is characterized by a faster decay and a higher frequency content compared to the crash cymbal. The advanced multiphysics vibro-acoustic simulations that correlate the displacements and velocities of the vibrated structure with the radiated sound pressure results demonstrate the future capability to synthesize the sounds of cymbal music instruments.