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Because of high pressure impulse noise emitted from the outlet of pneumatic equipment, an appropriate noise abatement device installed at the top of a venting outlet is compulsory. However, a given known noise reduction using a bronze-made sintered porous plug at the venting outlet is insufficient. An exploration of advanced noise reducing device is required. In this paper, three kinds of mufflers (Muffler A: with part AA (a bronze-made sintered porous inlet); Muffler B: with part BB (a casing with expansion cones and extended perforated/non-perforated tubes); and Muffler C: part AA (a bronze-made sintered porous inlet) + part BB (a casing with expansion cones and extended perforated/non-perforated tubes)) have been introduced and acoustically analyzed. To assist the optimization of mufflers composing of complicated acoustical mechanism, a finite element method using finite element method (run on COMSOL) together with a simplified objective function model and Genetic Algorithm (GA) is presented. Here, the simplified model of objective function is established by means of Artificial Neural Networks (ANNs). In addition, three kinds of frequencies, including one low frequency (500 Hz) and two high frequencies (3000 Hz, and 5000 Hz), have been chosen as the target frequencies during the muffler C’s optimization process. Consequently, considering a space-constrained situation, an optimally shaped muffler using both parameters D and L is efficiently accomplished within space-constraint situation.

Because venting noise emitted from high pressure valve often occurred in industry and is huge, the noise abatement of the venting noise to protect human’s hearing health is necessary. In order to depress the high speed noise, a muffler internally equipped with spiral perforated tube is presented. To mitigate this noise, a dissipative muffler with perforated spiral tube installed on the pipeline is proposed. To evaluate the acoustical performance, a finite element method using COMSOL software is adopted. Also, the sensitivity analyses of Transmission Loss (TL) of the proposed muffler with respect to (1) diameter of the spiral and perforated tube ( D), (2) pitch of the spiral tube ( L), (3) acoustical impedance of the dissipative acoustic material ( R), and (4) perforation rate of a perforated tube (σ) has been carried out. For the optimization studies, both Artificial Neural Network (ANN) and Genetic Algorithm (GA) to optimize the muffler parameters L and D are applied. Here, two high target frequencies (2000 and 3500 Hz) to optimize the proposed muffler are exemplified. Consequently, the hybrid design of perforated spiral tube optimized using ANN and GA will mitigate the high pressure valve noise efficiently.

This paper aims to eliminate the pneumatic noise using a muffler hybridized with a metal sintered bronzed porous material, a spiral tube, and expansion cones. In this paper three kinds of mufflers (Muffler A: with part AA (a bronze-made sintered porous inlet); Muffler B: with part BB (a casing with a spiral tube and expansion cones); and Muffler C: part AA (a bronze-made sintered porous inlet) + part BB (a casing with a spiral tube and expansion cones)) have been introduced. A finite element method run on the COMSOL software will be adopted in the acoustical analysis of the mufflers. The influence of TL with respect to two kinds of design parameters (QQ: the number of expansion cone; σ1: the acoustical flowing impedance of the acoustical wool) has been assessed. Simulated results reveal that the muffler C with acoustical components of AA and BB is superior to the other two mufflers. Moreover, the design parameters of QQ and σ1 have essential acoustical influence to the muffler C.

In this work, an optimal suspension system is proposed to reduce the oscillations/vibrations of the car's body and harvest some of the induced vibration energy. The usual shock absorbers are replaced with energy harvesters capable of not only absorbing vibrations for ride comfort but also regenerating electrical energy for onboard use. To investigate the efficiency of the proposed harvesters, the input to the vehicle wheels is assumed to come from a sawtooth-shaped speed bump or rumble speed strip. Also, given the coupling between the various degrees of freedom of the car (heave, pitch, etc.), a half-car model is adopted in the derivation of the equations of motion. To maximize the amount of energy harvested, the design parameters of the harvesters are obtained using the simulated annealing optimization technique with four objective functions. Many of the design parameters, including magnet size, coil turns, and coil layers, are adjusted during the optimization process. Constant and accelerated motions are considered in this study to maximize the generated electricity index and ride comfort efficiency. The simulation results showed that the optimized harvesters were able to regenerate a significant amount of energy while maintaining an acceptable ride comfort level.

A hybrid plant and aquarium system can save water via water circulation and filtering. In order to conveniently seed and harvest and breed in the aquarium, the system is a module. The seeding/harve...

Monitoring subsea environment requires sophisticated tools such as Autonomous or Remote Underwater Vehicles, submersible sensors, and very skilled manpower. Power is vital to the success of subsea missions especially in deep-waters where visibility is poor and the travel time from the surface to the seabed and vice versa takes a relatively long time. Therefore, renewable energy sources have been tapped into as a solution to continuously provide power to underwater vehicles, actuators, and sensors used/located in deep waters, such as the Gulf of Mexico or the North Sea. Previously, we designed a one-magnet energy harvester installed at the bottom of the sea to generate electricity for small sensors. In order to increase the electrical power production to provide power for a variety of devices, two kinds of energy harvesters (single-magnet and two-magnet) actuated via a buoy are proposed here. The produced voltage is fed to a signal conditioning rectifier to prep it for usage by sensors/actuators. The performance of the two proposed harvesters using the Genetic Algorithms generated parameter is presented for comparison. The simulation results showed that the electrical power generated by the two-magnet energy harvester using periodic wave motion is double that of the single-magnet energy harvester.

As the need for the daily household appliances and home security increases, the application of interaction technologies and electrical appliances used in smart home system has been widely developed...

Noise abatement by using efficient mufflers is compulsory, as venting noise, a type of huge noise in the industry, has a serious impact on human hearing. In order to reduce the noise abatement cost, the idea of using a muffler to suppress two kinds of venting noise sources arises. In this study, a muffler internally inserted with a screwed plate was proposed with two inlets and an outlet for exhaust venting. An analysis of the finite element method (FEM) was performed to estimate the muffler’s acoustical performance using the COMSOL program. A simplified objective function established by an artificial neural network (ANN) was trained to shorten the optimization procedure and linked to a genetic algorithm (GA). During the muffler analysis, both Rx (the outline dimension of the muffler) and D (the diameter of a straight and perforated tube) were chosen as design parameters. In addition, two target frequencies (1500 Hz and 2000 Hz) were specified during the optimization process. Consequently, the result reveals that the optimization of a screw muffler having two inlets and one outlet was efficiently assessed.

Plane wave theory has been used in predicting the acoustical performance of one-chamber straight mufflers. But, the acoustical effect of the mufflers at higher frequencies that are beyond the threshold of the cut-off frequency has been neglected. In addition, there is a need for a more compact muffler design for use inside a space-constrained working area. In order to improve the acoustical performance of straight mufflers, a space-constrained multi-chamber muffler using a more accurate predicting model in conjunction with an optimizer is proposed. In this paper, an eigen function that uses a three dimensional wave propagation to deduce the acoustical field as a four-pole matrix form is applied. An overall four-pole system matrix that multiplies individual matrices is adopted in evaluating the Transmission Loss (TL) for the hybrid mufflers. A circular and three-chamber straight muffler is introduced and optimized for various targeted tones using both Genetic Algorithm (GA) and Simulated Annealing (SA) Methods in conjunction with five objective functions (case A–case E). Before the optimization process is carried out, an accuracy check of the mathematical models for the circular one-chamber muffler is carried out. In order to verify the reliability of the GA and SA methods, a single-objective optimization of the three-chamber straight muffler at a targeted tone of 2000 Hz using GA method and SA method has been executed. Results reveal that the TL can be maximized at the targeted frequency when using either the GA method or the SA method. In addition, the noise reduction will increase if the number of chambers increases. Moreover, the acoustical performance of the mufflers will be reversely proportional to the diameter of the inlet/outlet tubes. Consequently, results reveal that the TL of the circular hybrid mufflers at targeted frequencies can be simultaneously improved by using the fourth and fifth strategies of objective functions in which the inverse of the summation summing up the individual target frequency’s deviation square between the targeted transmission loss and the predicted transmission loss has been built.

Continuous electrical power supplies are crucial for the success of deep-sea missions given the need for power to energize sensors, actuators, or light sources to monitor activities in deep...

A reactive muffler has been widely used in depressing venting noise emitted from industrial plants. As can be seen in a previous study, a perforated/ non-perforated tube inserted inside a chamber w...

Based on the phase-cancellation technique, multi-connected-tube mufflers have been applied in the noise elimination for industrial venting noise. On the basis of the transfer matrix method, most re...

This paper presents development and design for a research project and a course which can improve students’ learning and achievements. The base model and advanced model for an “autonomous line-track...

This study develops an automated prototype machine for a speaker coil and the positioning of plastic fixtures. Users need only to place the positioning fixtures and coils into the trays. The machine will then automatically set the coils into the plastic fixtures.The PLC (Programmable Logic Controller), the center of the system, and motors will drive the mechanism. According to the demand requested of the production line, the system is divided into three sections (upper, middle, and lower). The upper section is the plastic locating fixture and feeding system which is composed of motors and cylinders. A user needs only to place a plastic locating fixture into the top tank. The plastic locating fixture can be arranged, ordered, and automatically assembled by the automated transport mechanism. The middle section and lower section of the machine are positioned sleeve assembly systems and voice coil alignment systems. A rotating assembly system is composed of several cylinders. Its main function is to m...

Industry often utilizes acoustical hoods to block noise emitted from reciprocating compressors. How-ever, the hoods are large and bulky. Therefore, to diminish the size of the compressor, a compact discharge muffler linked to the compressor outlet is considered. Because the geometry of a reciprocating compressor is irregular, COMSOL, a finite element analysis software, is adopted. In order to explore the acoustical performance, a mathematical model is established using a finite element method via the COMSOL commercialized package. Additionally, to facilitate the shape optimization of the muffler, a polynomial neural network model is adopted to serve as an objective function; also, a Genetic Algorithm (GA) is linked to the OBJ function. During the optimization, various noise abatement strategies such as a reverse expansion chamber at the outlet of the discharge muffler and an inner extended tube inside the discharge muffler, will be assessed by using the artificial neural network in conjunction with the GA optimizer. Consequently, the discharge muffler that is optimally shaped will decrease the noise of the reciprocating compressor.

Enormous effort has been applied to research on mufflers hybridized with a single perforated plug tube; nonetheless, mufflers conjugated with multiple parallel perforated plug tubes that disperse venting fluid and reduce secondary noise have been overlooked. To this end, an analysis of the sound transmission loss of two-chamber mufflers with multiple parallel perforated plug tubes that are optimally designed to perform within a limited space will be presented. Here, using a decoupled numerical method, a four-pole system matrix for evaluating acoustic performance (sound transmission loss) is derived. During the optimization process, a simulated annealing method, which is a robust scheme utilized to search for the global optimum by imitating a physical annealing process, is used. Prior to dealing with a broadband noise, the sound transmission loss’s maximization relative to a one-tone noise (200 Hz) is produced to check the simulated annealing method’s reliability. The mathematical model is also confirmed for accuracy. To understand the acoustical effects brought about by the various tubes (perforated tubes, internally extended non-perforated tubes, and non-perforated tubes), mufflers with internally extended non-perforated tubes and non-perforated tubes have been evaluated. The optimization of three kinds of two-chamber mufflers hybridized with one, two, and four perforated plug tubes have also been compared. The results are revealing: the acoustical performance of mufflers conjugated with more perforated plug tubes decreases as a result of the decrement of the acoustical function for acoustical elements (II) and (III). Accordingly, in order to design a better muffler, an advanced presetting of the maximum (allowable) flowing velocity is necessary before an appropriate number of perforated plug tubes can be chosen for the optimization process.

This study introduces an automatic classification system that uses an electroacoustic analyzer to measure the frequency response of earphones. This system was designed using the Pro/E package and improved via testing. The system controller used in the study is the Microchip PIC18F4520 microcontroller. The controller is connected to an electroacoustic analyzer and various motor drives to control the process. The classification system is divided into two parts. The first part is the placement of the earpiece into a matrix tray. Two electric tables and a linear rail are adopted to build a two-axis X-Y table. Then, a device is introduced onto the X-Y table that moves the earpiece to the correct point and drops it into a10×10 matrix tray. The second part is the classification mechanism. According to the results of the frequency response, the earpieces can be organized into eight classes. When receiving the classification results from the frequency response measuring device, the controller will plot the...

The purpose of this paper is to develop an automated acoustic inspection platform for an earpiece manufacturing. An 8-pin detector has been designed to automatically locate a coil which is inside an earpiece drive. This 8-pin detector is composed of eight probes. Voltage data will be obtained by a A/D converter via scanning and reading the earpiece when the detector contacts the earpiece’s drive. The location of the coil can be ascertained from the voltage data. The automated acoustic inspection platform uses a microcontroller (PIC18F4520) to control the integrated system sequence and the actuators, including the pneumatic cylinder solenoid and the step motor drive.Developed, here, is an automated machine which moves earpieces from the plate of the earpiece to a claw. The claw, then, moves the earpiece into position to detect the coil’s location. After locating the coil using an 8-pin detector, an acoustic inspection process will be executed automatically. The time of the inspection process is abo...

Subsea engineering has become a thriving field that received a lot of attention from researchers and educators in recent years. The reason for the attention could be economical since many oil and gas fields are offshores, ecological due to pollution, or geological due to earthquakes and Tsunamis. The subsea environment is difficult to conquer and requires sophisticated tools to monitor such as Autonomous or Remote Underwater Vehicles (AUVs or ROVs), submersible sensors, and very skilled manpower. In this work, the focus is on how to supply power indefinitely to stationary sensors at the bottom of the sea. Therefore, an energy harvesting device is designed and simulated to validate its efficacy in supplying the necessary power to charge submersible sensors and their accessories. The device is actuated using water currents and the output voltage is fed through a voltage rectifier to convert it to the required DC input of the sensors. Simulations results showed that the designed device can successfully provide the necessary power for submersible sensors.

There has been wide-spread use of plane wave theory in muffler design in industry. However, This has led to an underestimation of acoustical performances at higher frequencies. To overcome the above drawback, the finite element and boundary element methods have been developed. Nevertheless, the time consumed in calculating the noise level is unacceptable. Moreover, considering the acoustical effect and necessity of space-constrained situation in industry, a compact design of reverse mufflers which may improve the acoustical efficiency is then proposed.In this paper, a numerical assessment of rectangular mufflers hybridized with straight/reverse chambers using eigen function, four-pole matrix, and genetic algorithm under limited space is developed. Before the optimization is performed, an accuracy check of the mathematical models for the muffler will be carried out. Results reveal that the noise reduction will increase when the number of chambers increases. In addition, the acoustical performance of the mufflers is reversely proportional to the diameter of the inlet/outlet tubes. Also, the TL of the mufflers will be improved when using more number of target tones in the objective function. Consequently, a successful approach in searching optimal shaped rectangular straight/reverse mufflers using an eigen function and a genetic algorithm method within a constrained space has been demonstrated.

In order to overcome the drawback of the accuracy for the Plane wave theory in the muffler’s acoustical calculation in the region of higher frequencies, we use a theoretical analysis of eigen function in conjunction with a four-pole system matrix to evaluate the TL of a circular straight muffler with bias inlet/outlet duct. With this method, the acoustical calculation can be speeded up comparing to traditional simulation of FEM and BEM method. Consequently, results reveal that the bias effect will tremendously influence the acoustical performance of the muffler.

The paper is an exploration of the optimal design parameters of a space-constrained electromagnetic vibration-based generator. An electromagnetic energy harvester is composed of a coiled polyoxymethylen circular shell, a cylindrical NdFeB magnet, and a pair of helical springs. The magnet is vertically confined between the helical springs that serve as a vibrator. The electrical power connected to the coil is actuated when the energy harvester is vibrated by an external force causing the vibrator to periodically move through the coil. The primary factors of the electrical power generated from the energy harvester include a magnet, a spring, a coil, an excited frequency, an excited amplitude, and a design space. In order to obtain maximal electrical power during the excitation period, it is necessary to set the system’s natural frequency equal to the external forcing frequency. There are ten design factors of the energy harvester including the magnet diameter (Dm), the magnet height (Hm), the system damping ratio (ζsys), the spring diameter (Ds), the diameter of the spring wire (ds), the spring length (ℓs), the pitch of the spring (ps), the spring’s number of revolutions (Ns), the coil diameter (Dc), the diameter of the coil wire (dc), and the coil’s number of revolutions (Nc). Because of the mutual effects of the above factors, searching for the appropriate design parameters within a constrained space is complicated. Concerning their geometric allocation, the above ten design parameters are reduced to four (Dm, Hm, ζsys, and Nc). In order to search for optimal electrical power, the objective function of the electrical power is maximized by adjusting the four design parameters (Dm, Hm, ζsys, and Nc) via the simulated annealing method. Consequently, the optimal design parameters of Dm, Hm, ζsys, and Nc that produce maximum electrical power for an electromagnetic energy harvester are found.

Research on plenums partitioned with multiple baffles in the industrial field has been exhaustive. Most researchers have explored noise reduction effects based on the transfer matrix method and the boundary element method. However, maximum noise reduction of a plenum within a constrained space, which frequently occurs in engineering problems, has been neglected. Therefore, the optimum design of multi-chamber plenums becomes essential. In this paper, two kinds of multi-chamber plenums (Case I: a two-chamber plenum that is partitioned with a centre-opening baffle; Case II: a three-chamber plenum that is partitioned with two centre-opening baffles) within a fixed space are assessed. In order to speed up the assessment of optimal plenums hybridized with multiple partitioned baffles, a simplified objective function (OBJ) is established by linking the boundary element model (BEM, developed using SYSNOISE) with a polynomial neural network fit with a series of real data – input design data (baffle dimensions) and output data approximated by BEM data in advance. To assess optimal plenums, a genetic algorithm (GA) is applied. The results reveal that the maximum value of the transmission loss (TL) can be improved at the desired frequencies. Consequently, the algorithm proposed in this study can provide an efficient way to develop optimal multi-chamber plenums for industry.

A reciprocating compressor is commonly used in industry. However, because it is extremely noisy and harmful to the ears, a noise control mechanism is necessary. Eight kinds of noise control strategies used with the reciprocating compressor are explored, and COMSOL, a numerical analysis software, is adopted for acoustical analysis in the paper. The primary purpose of this research is to assess the influence of seven noise control strategies for the suction/discharge muffler of a reciprocating compressor. Results have shown that the noise control strategies can efficiently improve the acoustical performance of the suction/discharge mufflers.

Ventilation equipment will inevitably deteriorate causing overheating problems that result in a machine breaking down. Therefore, to insure the safety of the machine, an auto- matic thermal control and online monitoring system is compulsory. In addition, to reduce manpower, a remote temperature monitoring/control system is proposed. Moreover, in order to recheck site status, an IP CAM used to audit current conditions will also be installed. The machine room will be equipped with a thermal detector, an auxiliary fan, and an alarm. The control system will also automatically detect current temperature in the machine room. Aux- iliary ventilation will be engaged when the temperature rises. An alarm unit will also be actu- ated when the temperature exceeds a preset limit. An image of the machine room captured by the IP CAM will be forwarded to both the server and the client via a TCP/IP protocol.Results reveal that the temperature for a machine room can be controlled online at a specified range. Additi...

There has been considerable research done on multi-chamber mufflers used in the elimination of industrial venting noise. However, most research has been restricted to lower frequencies using the plane wave theory. This has led to underestimating acoustical performances at higher frequencies. Additionally, because of the space-constrained problem in most plants, the need for optimization of a compact muffler seems obvious. Therefore, a muffler composed of multiple rectangular fin-shaped chambers is proposed. Based on the eigenfunction theory, a four-pole matrix used to evaluate the acoustic performance of mufflers will be deduced. A numerical case for eliminating pure tones using a three-fin-chamber muffler will also be examined. To delineate the best acoustical performance of a space-constrained muffler, a numerical assessment using the Differential Evolution (DE) method is adopted. Before the DE operation for pure tone elimination can be carried out, the accuracy of the mathematical model must be checked using experimental data. The results reveal that the broadband noise has been efficiently reduced using the three-fin-chamber muffler. Consequently, a successful approach in eliminating a pure tone using optimally shaped three-fin-chamber mufflers and a differential evolution method within a constrained space has been demonstrated.

At present, there is a trend to design a hard disk with a larger capacity, a faster revolution speed, and a precise mechanism. Therefore, the influence of data transmission with respect to vibration is obvious. To reduce interference of the vibrational impact on the data transmission efficiency, vibrational abatement on the hard disk using the damping material becomes crucial. Because of the complicated relationship for the damping coefficient and spring constant to the hardness (D1, D2, and D3) of the damping material installed under the hard disk, it is difficult to theoretically assess an optimal hardness combination of the damping material. Therefore, an alternative way by using an experimental study in conjunction with Taguchi method, an Artificial Neural Network (ANN), and a GA Method is proposed. In this paper, a hard disk is placed on a vibration tester that is an analogue to a dynamic vibrational circumstance induced by a vibrational base. The data transfer rate of the hard disk will be detected by using IOmeter software under various base-excitation accelerations, tilted angles of the hard disk, and targeted frequencies. To reduce the vibrational impact on the data transmission efficiency, an assessment of an optimal three-layer damping material installed under the hard disk using the Taguchi method, the Artificial Neural Network (ANN), and the GA Method is proposed. Before the optimization of the damping material is performed, the required experimental sets (the hardness for three layers of damping material) of the data transmission testing with respect to various design parameters will be determined by using the Taguchi method. The ANN, a simplified objective function (OBJ), will be established by inputting the hardness of three layers of damping material and their related data transmission efficiency at three targeted frequencies. Thereafter, the optimal hardness for three layers of the damping material will be obtained using a genetic algorithm (GA). Consequently, the optimal hardness of the three-layer damping material with respect to various tilted angles and target frequencies will be assessed.

Because of the greenhouse effect, global climate considerably changes and will worsen the water supply situations in future. Also, as can be seen in traditional reservoir, the crisis of water lacking will exacerbate due to the reservoir sedimentation. In order to widen the storage of water resources, a design of portable rain-collecting system used for irritation and daily use for people is presented. To facilitate the monitoring and manipulating, a rainwater collecting and storing system with green energy/automation /monitoring/control function is established. Considering the electricity shortage in remote island/mountain regions, two kinds of green energy generators (wind electrical generator and solar-board electrical device) are built and linked with the system. Here, a rain detector installed onto the roof can actuate the rainwater collecting board to raise and to collect water when raining event occurs. For the purpose of water purity, water filter is also set at the entrance of the water tank. In order to efficiently store/use the rainwater, several water storage tanks in conjunction with ecological pool are preset and adjusted via the water level gauge sensors and the pipe‘s solenoid valve. To meet the weather-proof ability, PLC is adopted as the controller. Moreover, a human-machine-interface is login on the internet and remotely communicated with the cell phone.Consequently, a prototype of the cell-phone base automatic rainwater collecting and storing system is established.

To obtain an optimal cutting process in the Computer Numerical Control (CNC), the multiple-quality production optimization decision is proposed by utilizing the tool nose run-off, the feed rate and the cutting depth as the control parameters. Four control factors that affect cutting quality will be examined: surface roughness, tool wear, material removal rate, and the cutting noise. Triz theory used in this study will define improved or depraved factors and then be substituted for the four objective aspects to construct the contradiction matrix table. Using the corresponding 40 inventive rules of Triz in the contradiction matrix table, the best decision in Triz will be found. The Triz single property principle is utilized to check the table to discover the cutting strategy order and to sort the game matrix. The Fahp is adopted to design a questionnaire. With this questionnaire, the weight of each factor and objective will be obtained. The weight of each factor is then used to classify the priority...