Development of a Microwave Technique to Predict Moisture Content in Mortar

This thesis describes a simple microwave nondestructive free space method at 17.2 GHz to determine the moisture content of mortar cement. The method is simple, fast, contactless and accurate way to determine the moisture content in mortar. The measurement system consists of a 17.2 GHz dielectric resonator oscillator (DRO) as a microwave source, Power Meter as the detector, a pair of lens horn antenna to transmit and receive microwave signal. The 17.2 GHz frequency was chosen since the sensitivity to the moisture content is higher at this frequency compared to the low frequency. The Agilent Visual Engineering Environment software was used to control and retrieve data from the Power Meter. The microwave part of the measurement system is setup to determine the amplitude of transmitted wave (received powers). A comparison of the two received powers (with sample and without sample) gives an estimate of the attenuation of the sample. The actual moisture content was found by applying standard oven drying method. The calculation and selection of mixture model were discussed thoroughly and only the best performance of mixture model was selected. The dielectric mixture equation (Lichtenecker Mixture Model) has been chosen to calculate the complex permittivity of sample and also predicted the attenuation of sample due to the smallest mean error compared to other models like Kraszewski and Landau. An optimization technique was used to improve the Lichtenecker model so that the mean error between measured and predicted can be reduced. A calibration equation relating the measured attenuation and moisture content was established and the sensitivity of the sensor is 2.8147 dB/ % moisture content. An empirical model of moisture content was obtained from improved attenuation formula and was tested to the sample. The measured and predicted attenuation were found in good agreement within ±5% of mean relative error

Design Broad Bandwidth Microwave Bandpass Filter Of 10 Ghz Operating Frequency Using HFSS

Microwave bandpass filter is the essential part in microwave circuits and wireless communication systems. This paper presents a new designing and simulation of broad bandwidth,low losses microwave bandpass filter operating at 10 GHz frequency using return loss method. The designing and simulation of the circuit has been carried out using Computer Aid Design (CAD) Ansoft HFSS software purchase from Ansys. The microwave filter circuit has designed with a parallel coupled line having a small dimension (10 × 10 mm2) of LaAlO3 substrate. The microwave circuit showed a high return loss -20 dB, broad bandwidth of 1.5 GHz, and operating frequency at 10 GHz. The results indicate the filter design and simulation using HFSS is reliable and have the opportunity to transfer from lab potential experiments to industry

Determination of moisture content in mortar at near relaxation frequency 17 GHz

The knowledge of moisture content in cement based material is important especially for the safety in field work. In this paper, a non-destructive and contactless free space method is used for measurement of moisture content in cement based materials (mortar) at microwave frequencies. The measurement system consists of a 17 GHz dielectric resonator oscillator (DRO) as a microwave source, a Power Meter as the detector, and a pair of lens horn antennas to transmit and receive the microwave signal. An empirical formula of moisture content was obtained by using a relationship between attenuation and moisture content. This model is best for prediction of moisture content greater than 2% with percentage mean error of 3%

Flat Ge-doped optical fibres for food irradiation dosimetry

Exposing food to radiation can improve hygiene quality, germination control, retard sprouting, and enhance physical attributes of the food product. To provide for food safety, radiation dosimetry in irradiated food is required. Herein, fabricated germanium doped (Ge-doped) optical fibres have been used. The fibres have been irradiated using a gamma source irradiator, doses in the range 1 kGy to 10 kGy being delivered. Using Ge-doped optical fibres of variable size, type and dopant concentration, study has been made of linearity, reproducibility, and fading. The thermoluminescence (TL) yield of the fibres were obtained and compared. The fibres exhibit a linear dose response over the investigated range of doses, with mean reproducibility to within 2.69 % to 8.77 %, exceeding the dose range of all commercial dosimeters used in evaluating high doses for the food irradiation industry. TL fading of the Ge-doped flat fibres has been found to be < 13%

Job Opportunities in Material(s) Technology

Materials are substances of universe which have properties that make them useful in structures, machines, devices, products, and systems. There are three closely connected areas of study related to materials, namely material(s) technology, materials engineering and materials science. Material(s) technology is a relatively comprehensive discipline that begins with the production of goods from raw materials to processing of materials into the shapes and forms needed for specific applications. Material(s) technologists work with materials such as metals, plastics, rubbers and ceramics. They study how the composition, structure, processing, and application of these materials, are inter-related

Monopole antenna technique for determining moisture content in the Dioscorea hispida tubers

This study demonstrates the determination of moisture content in D. hispida tuber using microwave technique. A network analyzer was used to measure the reflection coefficient of a monopole antenna inserted in D. hispida tuber at different percentage of moisture content. The actual moisture content of D. hispida tuber was determined using oven drying method. The reflection coefficient measurement was performed at operating frequency between 2 MHz and 4 GHz. The best operating frequency to model the relationship between the magnitude of reflection coefficient and moisture content in the D. hispida samples was found to be 0.8 GHz. The model based on measured data of sample D with a regression value of 0.9399 and1.71% error was the most accurate model to predict moisture content in D. hispida tuber

A simple procedure to determine complex permittivity of moist materials using standard commercial coaxial sensor

A simple procedure was developed to determine complex permittivity of moist materials for known percentage of moisture content at any frequency based using a standard commercial coaxial sensor. Polynomial fitting and Gaussian elimination method were applied to obtain a single equation of complex permittivity as a function of frequency and moisture content. The empirical equation was tested for new samples and was found to have mean error percentage of 5.14 % and 10.22 % for dielectric constant and loss factor, respectively, when compared to a commercial probe

The effect of power intensity properties of microwave modified oil palm trunk lumber

In the decade, oil palm (Elaeis guineensis) in Malaysia is one of the conventional sources that will be rising, and the rate of biomass will considerably increase in yet to come. Presently, oil palm biomass is going through research and development and appears to be the most sustainable alternative. Investigations on oil palm biomass have been conducted to support in draw out waste of oil palm and in the meantime can help economic yield to the country. This study was expected to estimate the effect of power intensity properties of microwave modified oil palm trunk lumber. Microwave treatment of oil palm trunk samples was set of connections by using a microwave operating at 2.45 GHz with the liberated process input power intensity (600-1000W) were studied under the given condition. Impact and compression of the samples were tested. The analysis of properties of the fresh material and dry samples was employed by scanning electron microscopy. Oven drying technique also was involved as a comparison of the conventional drying process in this research. Based on the outcomes of this study, both drying methods improved the characteristics of the specimens

Effect of processing parameters on the morphology, particulate, and superconducting properties of electrospun YBCO nanostructures

Superconductivity in nanostructured ceramics offers significant advantages over the conventional coarse-grained materials in view of miniaturization of superconducting electronic devices. In this paper, we report the formation of four morphologies of superconducting YBa2Cu3O7-δ (YBCO) nanostructures by electrospinning technique using polymeric polyvinyl pyrrolidone (PVP) solutions of different molecular weight and altering the total content of the metallic precursors. The morphologies prepared using this strategy are nanorods (NRs), nanogarlands (NGs), nanohierarchical (NH), and nanoparticles (NPs). Alternating current susceptibility measurements showed high critical temperatures (TC ~90 K) for the NH YBCO synthesized using PVP of the lowest molecular weight; whereas the YBCO NRs synthesized using a higher molecular weight polymer showed the lowest TC (82 K). A relationship between the particulate properties and TC was also observed – the lower is the pore size the higher is the TC. The YBCO NGs showed the highest specific surface area (7.06 m2/g) with intermediate TC (88 K). Electrospinning process appears an effective and controllable technique to produce different nanomorphologies with intrinsic properties suitable for practical applications

Piezoelectric properties of Mg doped ZnO thin film using sol-gel method and spin coating

This reports about the synthesis of Mg doped ZnO thin film using spin-coating techniques through sol-gel method. For studying piezoelectric properties, optical properties and morphology, the prepared Mg doped ZnO thin film samples were characterized using Ultraviolet-Visible Spectroscopy (UV-Vis), Photoluminescence Spectroscopy (PL), X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Ultrasonic Vibrator. The particle size was evaluated using Scherrer’s formula from XRD patterns. The results show the crystallite size decreased with increasing Mg concentrations. The optical properties showed that sample exhibit a blue shift in absorption in UV spectra indicating good optical properties. The morphology of grain size microstructure was observed from FESEM with results the grain size of the samples decreased with increasing Mg doping. The piezoelectric properties were evaluated using ultrasonic vibrator and multimeter to obtain potential difference for each sample. The results obtained that potential difference increase with increasing Mg contents and higher rotation of spin speed was used