absorption measurement
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Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1383
Author(s):  
Siti Anis Khairani Alwi ◽  
Syaza Nafisah Hisamuddin ◽  
Shahino Mah Abdullah ◽  
Afiq Anuar ◽  
Atiqah Husna Abdul Rahim ◽  
...  

In this work, we presented experimental observation on solution-processed bulk heterojunction organic photodiode using vanadyl 2,11,20,29-tetra tert-butyl 2,3 naphthalocyanine (VTTBNc) as a p-type material. VTTBNc is blended with two different acceptors, which are PC61BM and PC71BM, to offer further understanding in evaluating the performance in organic photodiode (OPD). The blend film of VTTBNc:PC71BM with a volumetric ratio of 1:1 exhibits optimized performance in the VTTBNc blend structure with 2.31 × 109 Jones detectivity and 26.11 mA/W responsivity at a −1 V bias. The response and recovery time of VTTBNc:PC71BM were recorded as 241 ms and 310 ms, respectively. The light absorption measurement demonstrated that VTTBNc could extend the light absorption to the near-infrared (NIR) region. The detail of the enhancement of the performance by adding VTTBNc to the blend was further explained in the discussion section.


2021 ◽  
Vol 263 (2) ◽  
pp. 4532-4537
Author(s):  
Toru Otsuru ◽  
Reiji Tomiku ◽  
Noriko Okamoto ◽  
Siwat Lawanwadeekul

The authors have been published a series of papers on a measurement method for sound absorption characteristics of materials using ensemble averaging technique, i.e., EA method. The papers' results included measurement mechanisms, measurement uncertainty, and so on. Herein, to examine adaptability, especially in in-situ conditions, the EA method is applied to measure absorption characteristics of materials installed in two gymnasiums. A glass-wool panel with the dimension of 0.5 m by 0.5 m by 0.05 m and with the density of 32 kg m^-3 was brought around and measured to check the measurement consistency. Several measurements were conducted during badminton plays were undergoing. Measured sound absorption coefficients revealed that most results agree well with those measured in reverberation rooms. Certain improvement is necessary for the specimen brought to the in-situ measurement to keep the consistency. The inconsistency is considered to originate from unstable conditions between the specimen and floor.


2021 ◽  
Vol 263 (2) ◽  
pp. 4008-4019
Author(s):  
Niels Peter Moos ◽  
Cheol-Ho Jeong ◽  
Mads Bolberg ◽  
Rasmus Stahlfest Holck Skov

For Sabine absorption coefficient measurements in reverberation rooms, it is preferable to excite as many room modes as possible. But the number of excited room modes is significantly affected by many factors, among which one dominating factor is the loudspeaker location particularly at frequencies below the Schroeder frequency. In turn, this could significantly influence the statistical absorption coefficient obtained according to ISO 354. Therefore, this study aims to investigate the impact of loudspeaker configurations on the excitation of room modes. Frequency response functions are measured using a broad band steady state noise signal using four sound sources at various locations, and the numbers of excited room modes in the one-third octave bands are quantified and compared against those by Green's function simulations. A procedure for determining favorable loudspeaker positions based on the excited room modes is proposed, which can be a useful input to the working group of the ISO 354 standard.


2021 ◽  
Author(s):  
I. Mbarek ◽  
M. Ben Gzaiel ◽  
A. Oueslati ◽  
M Gargouri

Abstract The single crystals of bi-tetrabutylphosphonium hexachlorostannate were grown by solvent evaporated method and characterized by X-ray powder diffraction, Raman spectroscopy and optical study. The X-ray powder diffraction indicates that it was crystallized in the monoclinic system, with C2/c space group. Besides, temperature-controlled X-ray diffraction show that the [P(C4H9)4]2SnCl6 compound indicate the presence of two phase transitions detected at 388 and 403 K. The evolution of Raman line shifts, “ν”, and the half-width, “Δν”, versus temperature show some singularities associated with the transitions, suggesting the important role of the anionic parts ((SnCl6)2-). Besides, the results of the Raman study confirms the conclusion drawn from the X-ray powder diffraction measurements that the phase transition are located near 388K and 403K.Furthermore, an optical absorption measurement confirms the semiconductor nature with a band gap equal to 3.46eV.


2021 ◽  
Vol 10 (2) ◽  
pp. 41
Author(s):  
Mei Sofiatul Hasanah ◽  
Yushardi Yushardi ◽  
Albertus Djoko Lesmono

The increase in Indonesia's development activities increases people's consumption of more quality construction materials and is easy to reach in terms of price. Building materials with good quality can improve the quality of building construction. The increasing need of the community for building materials triggered the development of the brick-making industry. Redbrick is an element of building used in building construction made from clay base material with or without other mixed materials. This research is a type of experimental research. The purpose of this study is to know and analyze the composition of the addition of corn bark ash and ash corn cob appropriately to produce the quality of bricks with high compressive strength, low water absorption, and large density. Additional materials in this study in the form of corn bark ash and ash corn cob. The quality of red bricks is seen from three aspects, namely compressive strength, water absorption, and density. The largest compressive strength was obtained in the addition of ash corn cob by 2.5% by 37.2 Kg/Cm2 and the compressive strength of 49.5 Kg/Cm2 on the addition of corn skin ash by 2.5%. Water absorption measurement of all types of red bricks the results of the study showed all the results of water absorption is not eligible sni. The highest density was obtained from a mixture of 2.5% ash corn cob material of 17.5 gr/Cm3. the best composition to produce bricks with strong compressive value and high density and have low water absorption is 2.5% addition of ash corn cob and the addition of 2.5% corn skin ash. Keywords: Red bricks, strong press, water absorption, density.


2021 ◽  
Vol 15 (4) ◽  
Author(s):  
Fu Li ◽  
Tian Li ◽  
Marlan O. Scully ◽  
Girish S. Agarwal

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