Development High Stiffness Ratio of Stiffened Membranes for Small Flat Speakers

2012 ◽  
Vol 538-541 ◽  
pp. 44-47
Author(s):  
Feng Min Lai ◽  
Meng Yu Wu ◽  
Cheng Mao Yang ◽  
Wei Sheng Shih
Keyword(s):  
Carbon Nanotubes ◽  
Sound Pressure ◽  
Membrane Surface ◽  
Spray Coating ◽  
Pressure Curve ◽  
Computer Aided Analysis ◽  
Coating Uniformity ◽  
Coating Methods ◽  
The Difference ◽  
Manufacturing Parameters

This research for the membrane stiffening manufacture, thickness, weight, manufacturing parameters, stiffness and surface uniformity was discussed. The used of hand rough paper as membrane substrate, and used of roller coating, spray coating of coating methods, and it carried on membrane stiffening process of carbon nanotubes. On the increase smallest weight, it had been a large increase in stiffness, and the flat speakers sound pressure curve smoother. Used different proportion of carbon nanotubes mixture of different resin to membrane stiffening, used SEM to detect the carbon nanotubes stiffening of the membrane surface coating uniformity, even different coating of compare thickness with weight of increase percentage. It used tensile test to explore different coating methods of Young's modulus of the difference. Then, we was manufactured the small plane speaker (L33mm×W21mm×H12mm) according to the various membrane stiffening and measure the sound pressure curve, and it contrasted with computer-aided analysis software obtained the theory of sound pressure curves.

scholarly journals Thermal Stresses Analysis and Optimized TTP Processes to Achieved CNT-Based Diaphragm for Thin Panel Speakers

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Feng-Min Lai ◽  
Chang-Yi Peng
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Thermal Stresses ◽  
Powder Coating ◽  
Curing Temperature ◽  
Metallic Surface ◽  
Work Piece ◽  
Pressure Curve ◽  
Thin Panel ◽  
Manufacturing Parameters

Industrial companies popularly used the powder coating, classing, and thermal transfer printing (TTP) technique to avoid oxidation on the metallic surface and stiffened speaker diaphragm. This study developed a TTP technique to fabricate a carbon nanotubes (CNTs) stiffened speaker diaphragm for thin panel speaker. The self-developed TTP stiffening technique did not require a high curing temperature that decreased the mechanical property of CNTs. In addition to increasing the stiffness of diaphragm substrate, this technique alleviated the middle and high frequency attenuation associated with the smoothing sound pressure curve of thin panel speaker. The advantage of TTP technique is less harmful to the ecology, but it causes thermal residual stresses and some unstable connections between printed plates. Thus, this study used the numerical analysis software (ANSYS) to analyze the stress and thermal of work piece which have not delaminated problems in transfer interface. The Taguchi quality engineering method was applied to identify the optimal manufacturing parameters. Finally, the optimal manufacturing parameters were employed to fabricate a CNT-based diaphragm, which was then assembled onto a speaker. The result indicated that the CNT-based diaphragm improved the sound pressure curve smoothness of the speaker, which produced a minimum high frequency dip difference (ΔdB) value.

scholarly journals Synergy Effects in Electromagnetic Properties of Phosphate Ceramics with Silicon Carbide Whiskers and Carbon Nanotubes

2019 ◽  
Vol 9 (20) ◽  
pp. 4388 ◽  
Author(s):  
Artyom Plyushch ◽  
Jan Macutkevič ◽  
Polina Kuzhir ◽  
Aliaksei Sokal ◽  
Konstantin Lapko ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Silicon Carbide ◽  
Wide Frequency Range ◽  
Electromagnetic Properties ◽  
Aluminium Phosphate ◽  
Silicon Carbide Whiskers ◽  
Synergy Effects ◽  
Multi Walled Carbon Nanotubes ◽  
The Difference ◽  
Walled Carbon Nanotubes

Hybrid composite materials based on an aluminium phosphate matrix with silicon carbide whiskers and multi-walled carbon nanotubes were studied in a wide frequency range (20 Hz to 36 GHz). It was demonstrated, that the addition of the silicon carbide whiskers enhances the dielectric permittivity and conductivity. This was explained by the difference in tunnelling parameters. Hybrid ceramics with nanotubes and whiskers also exhibits substantially improved electromagnetic shielding properties. The hybrid ceramics with 10 wt. % silicon carbide whiskers and a 1 mm thick 1.5 wt. % carbon nanotube layer, show higher than 50% absorption of electromagnetic radiation.

scholarly journals Improved Morphology of Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) Thin Films for All-Electrospray-Coated Organic Photovoltaic Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yingjie Liao ◽  
Takeshi Fukuda ◽  
Norihiko Kamata
Keyword(s):  
Thin Films ◽  
High Performance ◽  
Photovoltaic Cells ◽  
Spray Coating ◽  
Organic Photovoltaic ◽  
Organic Photovoltaic Cells ◽  
Ambient Conditions ◽  
Deposition Parameters ◽  
Coating Methods ◽  
Organic Devices

Spray coating technique has been established as a promising substitute for the traditional coating methods in the fabrication of organic devices in many reports recently. Control of film morphology at the microscopic scale is critical if spray-coated devices are to achieve high performance. Here we investigate electrospray deposition protocols for the fabrication of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films with a single additive system under ambient conditions at room temperature. Critical deposition parameters including solution composition, applied voltage, and relative humidity are discussed systematically. Optimized process for preparing homogenous PEDOT:PSS thin films is applied to all-electrospray-coated organic photovoltaic cells and contributes to a power conversion efficiency comparable to that of the corresponding all-spin-coated device.

Acceptable Levels of Tonal and Broad-Band Repetitive and Continuous Sounds during the Performance of Nonauditory Tasks

1995 ◽  
Vol 81 (3) ◽  
pp. 803-816 ◽  
Author(s):  
Ulf Landström ◽  
Anders Kjellberg ◽  
Marianne Byström
Keyword(s):  
Reaction Time ◽  
Sound Pressure ◽  
Broad Band ◽  
Reaction Time Task ◽  
Simple Reaction Time Task ◽  
Reasoning Test ◽  
Band Noise ◽  
Time Test ◽  
The Difference ◽  
Reaction Time Test

Three groups of 24 subjects were exposed to a 1000–Hz tone or broad band noise in a sound chamber. During the exposures subjects were engaged in an easy reaction time test or a difficult grammatical reasoning test. For each exposure and work subjects adjusted the noise to a tolerance level defined by its interference with task performance. During the simple reaction-time task significantly higher sound-pressure levels were accepted than during the reasoning test. At the tonal exposure, much lower levels were accepted than during the exposure to broad-band noise. For continuous sound exposures much higher levels were accepted than for noncontinuous exposures. For tonal exposures the difference was approximately 5 dB, for the broad-band exposures approximately 9 dB. In a separate study the effects of the noncontinuity of the noise and pauses were analysed. The raised annoying effect of the noncontinuous noise was not more affected by the noncontinuity of the noise periods than by the noncontinuity of the pauses. The results imply that the annoying reactions to the sound will be increased for repetitive noise and that the reaction is highly influenced by the over-all noncontinuity of the exposure.

scholarly journals A Simple Method for the Detection of Biofilms Using a Heatable Capacitive Sensor Structure (CSS): Description, Proof of Concept, and Some Technical Improvements

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 445
Author(s):  
Kai-Uwe Zirk ◽  
Manuel Olze ◽  
Harald Pötzschke
Keyword(s):  
Printed Circuit Boards ◽  
Free Water ◽  
Spray Coating ◽  
Internal Surface ◽  
Capacitive Sensor ◽  
Simple Method ◽  
Realistic Condition ◽  
Main Challenge ◽  
Sensor Structure ◽  
The Difference

This article presents a novel method for the detection of biofilms based on a heatable, capacitive sensor structure (CSS). Biofilms are capable of strongly binding large amounts of water to their extracellular biopolymer matrix, which is detectable via its dielectric properties. A main challenge is to determine the difference between the inherent occurring presence of moisture in the ecosystem, which is necessary to form a biofilm and an actual formed biofilm. Therefore, the CSS is carefully heated to evaporate unbound surface moisture and determine whether there is a remaining residual alternation of the capacitance in comparison to the dry state. As a reproduceable substitute for complex, real biofilms, a hygroscopic, medical hydrogel-based on polysaccharides was used and applied by spray coating. Printed circuit boards (PCB) in different geometries and materials were used as CSS and compared in terms of their performance. A layer-thickness of 20 µm for the hydrogel coating to be sufficiently detected was defined as a realistic condition based on known values for real biofilms cited in literature. For this thickness a double-meander structure proves to be preferable over interdigitating and spiral geometries. It does offer a 30% lower, yet sufficient sensitivity, but shows advantages in manufacturing (one layer instead of two) and conductive heating capability. In the experiments, free water showed virtually no residual change, while the hydrogel-coated CSS still shows an approx. 300% higher value compared to a dry capacity. Yet, the overall small capacities of about 6–30 pF in dry state are difficult to measure and therefore sensitive to interferences and noise, which results in a high deviation. The principle of measurement can be evaluated as proofed by the carried out experiments, though offering room for improvement in the design of the study. The new method might be especially useful for pipes (e.g., hydrodynamically ineffective sensors installed in a pipe wall) if they at least are not permanently flooded with an aqueous medium, but can occasionally dry. If the internal surface is still only moist, it can be dried by initial heating.

scholarly journals The Effect of Frequency Acoustic Stimulation Sound on Intrauterine Weakening of Pregnant Sheep

2017 ◽  
Vol 3 (6) ◽  
pp. 125
Author(s):  
Djamil Suherman ◽  
Hermanto Tri Joewono ◽  
I Komang Wiarsa Sardjana
Keyword(s):  
Abdominal Wall ◽  
Sound Pressure ◽  
Acoustic Stimulation ◽  
Uterine Wall ◽  
Sound Frequency ◽  
Pregnant Sheep ◽  
Post Test ◽  
The Difference ◽  
Level Of Sound Pressure ◽  
Veterinary Faculty

Research to determine changes in intrauterine sound pressure in pregnant sheep after administration acoustic stimulation outside of the abdominal wall at some frequency sounds. The study was conducted at the Animal Hospital of Veterinary Faculty of Airlangga University. Pre test experimental design with pre- and post-test one group to assess intra-uterine sound pressure changes. The study was conducted at two lambs pregnant aterm after acoustic stimulation at a distance of 10 cm from the surface of the abdominal wall to the sound pressure 80,85,90,95 and 100 decibels and sound frequency of 31.5, 63, 125, 250, 500, 1000, 2000, 4000, 6000 and 8000 hertz. The results showed that the difference between the sound pressure outside of the abdominal wall with intrauterine sound pressure on both the pregnant sheep by an average of 16.7570 ± 8.0797 decibels. This shows their weakening sound after passing through the abdominal wall and the uterine wall. By using a paired t-test, this weakening statistically significant. At frequencies from 31.5 to 1000 hertz weakening values from 5.2 to 17.1 decibels while in 2000-8000 hertz frequency weakening value of 20.2 to 30.8 decibels. The conclusion that the stimulation of noise from outside the walls of the abdomen weakening sound after penetrating the abdominal wall and the uterine wall. Weakening occur at every level of sound pressure and at every level of a given frequency. Weakening value becomes greater at frequencies above 1000 hertz.                                                                                                       Keywords: weakening, sound pressure, sound frequency, pregnant sheep.

Highly effective permeability and antifouling performances of polypropylene non-woven fabric membranes modified with graphene oxide by inkjet printing and immersion coating methods

2013 ◽  
Vol 67 (10) ◽  
pp. 2307-2313 ◽  
Author(s):  
Chuan-Qi Zhao ◽  
Xiao-Chen Xu ◽  
Rui-Yun Li ◽  
Jie Chen ◽  
Feng-Lin Yang
Keyword(s):  
Graphene Oxide ◽  
Inkjet Printing ◽  
Membrane Surface ◽  
Pure Water ◽  
Woven Fabric ◽  
Water Permeation ◽  
Lower Protein ◽  
Coating Methods ◽  
And Performance ◽  
The Impact

In the current study, graphene oxide (GO)-modified polypropylene non-woven fabric (PP-NWF) membranes were prepared via inkjet printing and immersion coating methods. Scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle measurements, pure water permeation (JPWP) and protein adsorption were tested to evaluate the impact of the GO nanosheet on the characteristics and performance of modified PP-NWF membranes. The results showed that the exfoliated GO nanosheets uniformly deposited on the membrane surface and firmly embedded into the interlaced fibers, resulting in the improvement of membrane hydrophilicity, permeability and antifouling properties comparing with original PP-NWF membranes. The GO-printed and GO-coated membranes had 113 and 188% higher fluxes, and 70.95 and 75.74% lower protein adsorptions than the original PP-NWF membranes, respectively. After cross-linked treatment, ultrasound processing was conducted to evaluate the stability of the modified PP-NWF membranes. The results demonstrated that there was almost no decrease in permeation after ultrasonic treatment indicating that the cross-linking treatment could enhance the immobilization of the GO nanosheets on and into the modified membranes.

DETERMINATION OF GROWTH DIRECTION OF CARBON NANOTUBES FROM THE SHAPE OF THE CATALYST PARTICLE

2011 ◽  
Vol 10 (04n05) ◽  
pp. 1045-1050 ◽  
Author(s):  
K. P. S. S. HEMBRAM ◽  
K. REDDAPPA REDDY ◽  
G. MOHAN RAO
Keyword(s):  
Carbon Nanotubes ◽  
Tip Growth ◽  
Flow Direction ◽  
Catalyst Particle ◽  
Forward Direction ◽  
Growth Direction ◽  
Morphological Studies ◽  
Simple Geometry ◽  
The Difference

We present a mechanism that can explain the growth direction of the carbon nanotubes (CNT), based on the observation of the catalyst particle's shape, that is present along with the CNT. We claim the mechanism holds good for the tip growth as well as the base growth model for CNTs formation. The morphological studies performed using simple geometry show that for encapsulated catalyst, (i) the contact angle is less along the forward direction than that of backward direction, (ii) the growth direction of CNT is along the flow direction of the catalyst particle in the fluid state, (iii) the distance between the centre of two imaginary spheres (circles in 2D) drawn at the front and back of the catalyst particle, qualitatively predicts the difference in growth rate of the CNT and flow of the catalyst particle inside the CNT. In order to support the above claims, a generalized model is proposed, irrespective of the position of the catalyst.

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