Microwave wide band absorption by carbon from Corn cob-1

2016 ◽  
Vol 12 (2) ◽  
pp. 4204-4212 ◽  
Author(s):  
Maheshwar Sharon ◽  
Ritesh Vishwakarma ◽  
Abhijeet Rajendra Phatak ◽  
Golap Kalita ◽  
Nallin Sharma ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Agricultural Waste ◽  
Wide Band ◽  
Nickel Nitrate ◽  
Equivalent Amount ◽  
Frequency Range ◽  
Corn Cob ◽  
Different Temperatures ◽  
Band Absorption ◽  
5 Ghz

Corn cob, an agricultural waste, is paralyzed at different temperatures (700oC, 800oC and 900oC). Microwave absorption of carbon in the frequency range of 2 GHz to 8 GHz is reported. Carbon activated  with 5%  nickel nitrate showed more than 90% absorption of microwave in the frequency range from 6 GHz to 8 GHz, while carbon activated  with 10% Nickel nitrate treated corn cob showed 90% absorption  in the frequency range of 2.5 GHz to 5 GHz. Carbon showing the best absorption are characterized by XRD, Raman spectra and SEM . It is suggested that corn cob treatment   alone with KOH did not improve the microwave absorption, whereas treatment along with nickel nitrate improved the absorption property much better. It is proposed that treatment with nickel nitrate helps in creating suitable pores in carbon   which improved the absorption behavior because while treating carbon with 1N HCl helps to leach out nickel creating equivalent amount of pores in the carbon.

A Multiple-Bands Metamaterial Absorber Based in X, Ku and K-Band

2021 ◽  
Author(s):  
Muhammad Fahim Zafar ◽  
Usman Masud
Keyword(s):  
Single Layer ◽  
Wide Band ◽  
Metamaterial Absorber ◽  
Basic Unit ◽  
Frequency Range ◽  
Structure Form ◽  
Perfect Absorption ◽  
Polarization Insensitive ◽  
Band Absorption ◽  
K Band

Abstract Developing a highly efficient and multiple-bands metamaterial absorber is a hot issue in recent era. In this paper, A multiple-bands metamaterial absorber has been presented which is based in X, Ku and K-band. Firstly, we have designed two single layer basic unit cell of X-shape and cross-shape, then they are arranged in the multi-layers structure form for the purpose of obtaining multiple- bands and wide band absorption. The proposed absorber is able to work in multiple bands because it has six peaks in the frequency range of 8–24 GHz with having near perfect absorption. Moreover, the sixth peak has a wideband absorption which is 2.93 GHz. Furthermore, the proposed absorber is also tested for polarization insensitivity and also for oblique incidence. Absorption was found polarization insensitive with almost perfect absorption.

Achieving wideband microwave absorption properties in PVDF nanocomposite foams with an ultra-low MWCNT content by introducing a microcellular structure

2020 ◽  
Vol 8 (1) ◽  
pp. 58-70 ◽  
Author(s):  
Biao Zhao ◽  
Jiushuai Deng ◽  
Chongxiang Zhao ◽  
Chongda Wang ◽  
Yu Guang Chen ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
High Efficiency ◽  
Wide Band ◽  
Light Weight ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Mwcnt Content ◽  
Small Thickness ◽  
Nanocomposite Foams ◽  
Band Absorption

PVDF nanocomposite foams with ultra-low MWCNT content exhibit high-efficiency microwave absorption properties with a light weight, strong and wide-band absorption, and small-thickness properties.

scholarly journals Independently Tunable Multipurpose Absorber with Single Layer of Metal-Graphene Metamaterials

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 284
Author(s):  
Chen Han ◽  
Renbin Zhong ◽  
Zekun Liang ◽  
Long Yang ◽  
Zheng Fang ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Fermi Level ◽  
Potential Application ◽  
Single Layer ◽  
Wide Band ◽  
Metamaterial Absorber ◽  
Unit Cell ◽  
Perfect Absorption ◽  
Solar Energy Harvesting ◽  
Band Absorption

This paper reports an independently tunable graphene-based metamaterial absorber (GMA) designed by etching two cascaded resonators with dissimilar sizes in the unit cell. Two perfect absorption peaks were obtained at 6.94 and 10.68 μm with simple single-layer metal-graphene metamaterials; the peaks show absorption values higher than 99%. The mechanism of absorption was analyzed theoretically. The independent tunability of the metamaterial absorber (MA) was realized by varying the Fermi level of graphene under a set of resonators. Furthermore, multi-band and wide-band absorption were observed by the proposed structure upon increasing the number of resonators and resizing them in the unit cell. The obtained results demonstrate the multipurpose performance of this type of absorber and indicate its potential application in diverse applications, such as solar energy harvesting and thermal absorbing.

Production and optimization of cellulase from agricultural waste and its application in bioethanol production by simultaneous saccharification and fermentation

2016 ◽  
Vol 27 (1) ◽  
pp. 22-35 ◽  
Author(s):  
Elsa Cherian ◽  
M. Dharmendira Kumar ◽  
G. Baskar
Keyword(s):  
Design Methodology ◽  
Simultaneous Saccharification And Fermentation ◽  
Agricultural Waste ◽  
Cellulase Production ◽  
Reducing Sugar ◽  
Bioethanol Production ◽  
Corn Cob ◽  
Content Type ◽  
Optimized Conditions ◽  
Simultaneous Saccharification

Purpose – The purpose of this paper is to optimize production of cellulase enzyme from agricultural waste by using Aspergillus fumigatus JCF. The study also aims at the production of bioethanol using cellulase and yeast. Design/methodology/approach – Cellulase production was carried out using modified Mandel’s medium. The optimization of the cellulase production was carried out using Plackett-Burman and Response surface methodology. Bioethanol production was carried out using simultaneous saccharification and fermentation. Findings – Maximum cellulase production at optimized conditions was found to be 2.08 IU/ml. Cellulase was used for the saccharification of three different feed stocks, i.e. sugar cane leaves, corn cob and water hyacinth. Highest amount of reducing sugar was released was 29.1 gm/l from sugarcane leaves. Sugarcane leaves produced maximum bioethanol concentration of 9.43 g/l out of the three substrates studied for bioethanol production. Originality/value – The present study reveals that by using the agricultural wastes, cellulase production can be economically increased thereby bioethanol production.

scholarly journals Band notched self complementaryultra wideband antenna for wireless applications

2018 ◽  
Vol 7 (2.8) ◽  
pp. 529 ◽  
Author(s):  
Ch Ramakrishna ◽  
G A.E.Satish Kumar ◽  
P Chandra Sekhar Reddy
Keyword(s):  
High Frequency ◽  
Return Loss ◽  
Wide Band ◽  
Ultra Wideband ◽  
Impedance Bandwidth ◽  
Relative Dielectric Permittivity ◽  
Frequency Range ◽  
Ground Structure ◽  
Wireless Applications ◽  
Patch Edge

This paper presents a band notched WLAN self complementaryultra wide band antenna for wireless applications. The proposed antenna encounters a return loss (RL) less than -10dB for entire ultra wideband frequency range except band notched frequency. This paper proposes a hexagon shape patch, edge feeding, self complementary technique and defective ground structure. The antenna has an overall dimensionof 28.3mm × 40mm × 2mm, builton  substrate FR4 with a relative dielectric permittivity 4.4. And framework is simulated finite element method with help of high frequency structured simulator HFSSv17.2.the proposed antenna achieves a impedance bandwidth of 8.6GHz,  band rejected WLAN frequency range 5.6-6.5 GHz with  vswr is less than 2.

Anderson-Stuart Model to Analyze AC and DC Conductivity of Lithium Zinc-Silicate Glass / Glass-Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 919-924
Author(s):  
M.S. Jogad ◽  
V.K. Shrikhande ◽  
A.H. Dyama ◽  
L.A. Udachan ◽  
Govind P. Kothiyal
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Low Frequency ◽  
Frequency Region ◽  
Dc Conductivity ◽  
Frequency Range ◽  
High Frequency Region ◽  
Dc Conductivities ◽  
Conductivity Variation ◽  
Different Temperatures

AC and DC conductivities have been measured by using the real (e¢) and imaginary (e¢¢) parts of the dielectric constant data of glass and glass-ceramics (GC) at different temperatures in the rage 297-642K and in the frequency range 100 Hz to 10 MHz. Using Anderson –Stuart model, we have calculated the activation energy, which is observed to be lower than that of the DC conductivity. The analysis for glass/glass-ceramics indicates that the conductivity variation with frequency exhibits an initial linear region followed by nonlinear region with a maximum in the high-frequency region. The observed frequency dependence of ionic conductivity has been analyzed within the extended Anderson–Stuart model considering both the electrostatic and elastic strain terms. In glass/glassceramic the calculations based on the Anderson-Stuart model agree with the experimental observations in the low frequency region but at higher frequencies there is departure from measured data.

BaTiO3@C Core–Shell Nanoparticle/Paraffin Composites for Wide-Band Microwave Absorption

2021 ◽  
Author(s):  
Yujing Zhang ◽  
Yilin Zhang ◽  
Yuping Li ◽  
Minhao Yao ◽  
Xuefei Miao ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Wide Band ◽  
Core Shell

scholarly journals Using Diaper Waste to Prepare Magnetic Catalyst for the Synthesis of Glycerol Carbonate

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jincan Wang ◽  
Yong Liang ◽  
Song Wang ◽  
Patrick U. Okoye ◽  
Hongxu Chen ◽  
...  
Keyword(s):  
Magnetic Property ◽  
Calcination Temperature ◽  
Separation Process ◽  
Nickel Nitrate ◽  
Glycerol Carbonate ◽  
Magnetic Catalyst ◽  
Catalyst Separation ◽  
Different Temperatures

Diaper waste was calcined above 400°C after impregnated in the solution of nickel nitrate. The as-prepared diaper waste-derived materials were used as magnetic catalysts for the synthesis of glycerol carbonate (GC). Structure and catalytic ability investigations on the catalysts calcined at different temperatures indicated that calcination temperature was an important factor affecting the property of catalysts. It was found that the catalyst obtained at the calcination temperature of 700°C (named DW-Ni-700) showed the best performance. When DW-Ni-700 was used in the synthesis of GC, GC yield reached 93.2%, and the magnetic property of DW-Ni-700 facilitated the catalyst separation process. Meanwhile, DW-Ni-700 showed high reusability in the reaction. After four times reuse of DW-Ni-700, GC yield decreased less than 4%.

Magnetization and Microwave Absorption Properties of La0.67 Sr0.33 MnO3 with Different Particle Size

2011 ◽  
Vol 374-377 ◽  
pp. 1541-1544 ◽  
Author(s):  
Yu Lan Cheng ◽  
Ping Xia ◽  
Ke Xiang Wei ◽  
Quan Bai
Keyword(s):  
Particle Size ◽  
Sinter Temperature ◽  
Microwave Absorption ◽  
Reflection Loss ◽  
Sol Gel ◽  
Frequency Range ◽  
Absorption Properties ◽  
Microwave Absorption Properties ◽  
Measured Frequency Range ◽  
Maximum Reflection Loss

La 0.67 Sr 0.33 MnO 3 particles with different particle size have been prepared by sol-gel method. The structure, magnetization and microwave absorption properties have been investigated. The results show that the particle size can be controlled by sinter temperature. The peaks of the maximum reflection loss (RL) move to higher frequency regions with increasing particle size. The value of the maximum RL is -32 dB at 10.2GHz with a particle size of 58.5nm. The bandwidth with a RL exceeding -8dB reached 1.6GHz in the whole measured frequency range, suggesting that La 0.67 Sr 0.33 MnO 3 particles are promising for application as a wideband and strong absorption building microwave absorber.

scholarly journals ADSORPSI KARBON AKTIF DARI TONGKOL JAGUNG SEBAGAI ADSORBEN ION LOGAM Cu2+

2017 ◽  
Vol 2 (1) ◽  
pp. 24
Author(s):  
Dewi Putri Yuniarti
Keyword(s):  
Adsorption Capacity ◽  
Active Carbon ◽  
Metal Ion ◽  
Agricultural Waste ◽  
Mesh Size ◽  
Ash Content ◽  
Corn Cob ◽  
Waste Water Sample ◽  
Work Shop

Many reseerches about agricultural waste shows potency from this waste to be used as high quality of active carbon that can be used as (adsorbent) on gasoline and substances dissolved at solution. One of agricultural result in South Sumatera that is enough corn cob, where is solid waste that throun just. It is impossible since corncob contains about 40 % of cellulose. So, cellulose which can be used as an active carbon. There are two basic processes in the active carbon making, those are carbonization and activation. The aim of this study was to find out how the activated time gave influence to the adsorption capacity of active carbon as the metal ion Cu2+ adsorbent. The obtained data were analysed by using Atomic Adsorption Spectrophotometry (SNI 06-6989.6-2009). Moreover, the characteristic of the active carbon was ansalysed by Standart Nacional Indutrial (SNI 06-3730-1995). From the result of study, it was obtained that the activated time of 60 minutes with the activator H3PO4 0,5 M had the best adsorption capacity of 1.97 mg/g with the metal ion Cu2­+ concentration was 0,80 ppm. The characteristic of the missing part 9500C  20.54 %, water content of 11 %, ash content of 7 % and iodine number of 750.35 mg/g, pure active carbon 72.46 %, the density of bulk 0.31 g/ml, pass for the mesh size of 325 is 98 %. The adsorption capacity of active carbon from the corncob to the metal ion Cu2+ taken from the waste water sample at the shipyard painting work shop in Palembang was 0.1644 mg/g (97.60 %). Key words : Activated Carbon, Corn cob, Adsorption, AAS,  Copper (II) Metal Ion.

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