Effect of Y2O3 doping on the electrical transport properties of Sr2MnNiFe12O22 Y-type hexaferrite

Muhammad Irfan,M.U. Islam,Irshad Ali,M. Asif Iqbal,Nazia Karamat,Hasan M. Khan 한국물리학회 2014 Current Applied Physics Vol.14 No.1

Y2O3 doped Y-type composite hexa-ferrites Sr2MnNiFe12O22 þ xY2O3 (x ¼ 0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%) were synthesized successfully using sol-gel auto combustion technique. X-ray diffraction analysis reveals Y-type hexagonal structure with few traces of secondary phases. The decrease in grain size as a function of Yttrium content is attributed to the fact that Yttrium acts as a grain inhibitor. The DC resistivity was observed to increase with increasing Yttrium-contents due to the unavailability of Fe3þ ions at octahedral sites. Activation energy showed that the samples with high resistivity have high value of activation energy and vice versa. Permittivity decreases with the increase of frequency following MaxwellWagner Model. In addition, the doped samples exhibit very low dielectric constant and low loss tangent in frequency range 20 Hze1 MHz. The sample x ¼ 5 wt% exhibit the lowest value of dielectric constant. The variation in imaginary part of dielectric constant and loss tangent with frequency show normal dielectric behavior for all the samples. The frequency dependent ac conductivity increases with increase in frequency and decrease with Y2O3 doping. These characteristics may be suitable for their potential applications in electromagnetic attenuation materials and microwave devices. The conductivity mechanism so determined was hopping mechanism. The dc resistivity of the doped ferrites measured in our case is about 1010 U-cm that meets the requirement for fabrication of components by electroplating.

A Comparative Study on the Efficiency of Locally Made Low Cost Brooders for Brooding Chicks

Hassanuzzaman, M.,Ahammad, M.U.,Bulbul, S.M.,Nurul Alam, A.M.M.,Islam, M.A. Asian Australasian Association of Animal Productio 2004 Animal Bioscience Vol.17 No.11

An experiment was carried out with day-old "Sonali" (♂RIR$\times$♀Fayoumi) chicks to investigate the efficacy of locally made low cost brooders for brooding chicks in rural areas. Three types of indigenous brooders viz. charcoal, haricane and sawdust brooders were used for brooding chicks throughout the experimental period of 28 days. The efficiency of the brooders was observed in respect of their ability to maintain temperature, fluctuation in temperature during operation and cost effectiveness. Following initial trial of temperature maintenance for 48 h, the chicks were put under the brooder stoves and brooded up to 28 days. The experimental birds were fed on chick starter diet. Maintenance of temperature with sawdust brooders was found satisfactory and optimum for brooding the chicks at different stages of brooding and at the same time involved least cost for brooding in comparison with charcoal and haricane brooders which did not perform well in generating heat necessary for brooding and were not economically feasible for poor farmers. On the other hand, performance of charcoal brooders was better in respect of temperature maintenance during initial stage (when the brooder was started) but the temperature fluctuated rapidly, whereas fluctuation of temperature was gradual in sawdust brooders. Body weight gain and feed conversion were best in sawdust brooders. Survivability was highest in sawdust brooders and lowest in haricane brooders. Sawdust brooders may be appropriate for brooding chicks in rural areas, where electricity is not available.

Design and implementation of an automated monitoring system

Islam, M. S.,Lee, J. C.,Chong, U. Springer Science + Business Media 2016 The Journal of supercomputing Vol.72 No.11

<P>One of the main limitations of existing monitoring systems is their dependency on the continuous recording of video data. As a result, the system consumes huge power and needs large memory to store this data. The aim of this paper is to present an automated monitoring system that can save memory, as well as measure the target distance precisely based on the motion sensors and ultrasonic sensor. The target is detected by motion sensors and then an ultrasonic sensor is used to measure the target distance. The cross-correlation technique is used to calculate the distance of targets using ultrasonic signal. To obtain high measuring accuracy, noise reduction technique and temperature effect on velocity have been adopted. A series of real-world experiments are conducted with different targets and target positions. The experimental results show that using a noise reduction technique and temperature compensation improve the accuracy of the designed system.</P>

Strategies for cost-effective and enhanced production of bacterial cellulose

Islam, M.U.,Ullah, M.W.,Khan, S.,Shah, N.,Park, J.K. Elsevier 2017 INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES Vol.102 No.-

Bacterial cellulose (BC) has received substantial attention because of its high purity, mechanical strength, crystallinity, liquid-absorbing capabilities, biocompatibility, and biodegradability etc. These properties allow BC to be used in various fields, especially in industries producing medical, electronic, and food products etc. A major discrepancy associated with BC is its high production cost, usually much higher than the plant cellulose. To address this limitations, researchers have developed several strategies for enhanced production of BC including the designing of advanced reactors and utilization of various carbon sources. Another promising approach is the production of BC from waste materials such as food, industrial, agricultural, and brewery wastes etc. which not only reduces the overall BC production cost but is also environment-friendly. Besides, exploration of novel and efficient BC producing microbial strains provides impressive boost to the BC production processes. To this end, development of genetically engineered microbial strains has proven useful for enhanced BC production. In this review, we have summarized major efforts to enhance BC production in order to make it a cost-effective biopolymer. This review can be of interest to researchers investigating strategies for enhanced BC production, as well as companies exploring pilot projects to scale up BC production for industrial applications.

Design & Feasibility Analysis of Free to Walk

Dr. Hasan U. Zaman,Chowdhury,Nahian,Ghani,Uddin,Baized,Islam,S. M. Hasibul Hoq,Nazia Nawar Hassan 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.1

This paper introduces a mobile application suitable to use in smartphones useful for physically handicapped people. The mobile app “Free to walk” is a mobile application which will guide users to do physical exercises properly. Specially for handicapped people and also a useful humanitarian concept. This app can help a major percentage of physically handicapped people and also can make their life less measurable by using the instructions and tutorials based on physical exercises and physiotherapy available in application. This mobile application is helping people to get treatment sitting at their homes and also added a new dimension for fighting against physical challenges of physically handicapped people. Feasibility analysis is shown to define uniqueness of the concept. The end result shows the efficiency in practical operation. This paper also ensures future research possibilities in medical sector.

Synthesis and characterization of hexagonal ferrite Co2Sr2Fe12O22 with doped polypyrrole composites

Irshad Ali,Abdul Shakoor,M.U. Islam,Muhammad Saeed,Muhammad Naeem Ashiq,M.S. Awan 한국물리학회 2013 Current Applied Physics Vol.13 No.6

Y-type hexagonal ferrite Co2Sr2Fe12O22 was prepared by microemulsion route. A conducting polymer,polypyrrole was chemically synthesized and doped with dodecylbenzenesulphonic acid (PPy$DBSA). FTIR and magnetic properties of Co2Sr2Fe12O22 were investigated and compared with composite made by mixing the Co2Sr2Fe12O22 with this conducting polymer PPyeDBSA by 1:1 molar ratio. Phase analysis was performed by using X-ray diffraction (XRD). The microstructure was examined by scanning electron microscopy (SEM) showing heterogonous distribution of grains. The field dependent magnetic properties of the prepared samples were investigated at room temperature by using vibrating sample magnetometer (VSM). It has been observed that mixing of polymer in ferrite plays a crucial role in enhancing the coercivity, while saturation magnetization (Ms) and remanance were observed to decrease. Due to fine grain size, the density of grain boundaries increases where the domain wall pinning can take place,hence the coercivity of the composite samples increases. Appreciable improved value of coercivity guaranteed the use of these synthesized materials in the recording media, which is ¼1896(Oe) in the present samples. The suitable signal-to-noise ratio in the high density recording media can be achieved due to small particles size of this synthesized composite, which is expected in the present ferriteepolymer composite sample.