Detection of mercury ion (Hg2+) on chitosan film using microstrip interdigital capacitor

The use of interdigitated capacitor (IDC) for detection of mercury ion (Hg2+) absorbed by the chitosan film is presented in this paper. The effect of the ion concentration on the transmission coefficient (S21) value and the capacitance value is presented. The results show that the capacitance value as well as the S21 increased with increasing concentration of the metal ion absorbed

Properties of barium strontium titanate at millimeter wave frequencies

The trend towards using higher millimetre-wave frequencies for communication systems has created a need for accurate characterization of materials to be used at these frequencies. Barium Strontium Titanate (BST) is a ferroelectric material whose permittivity is known to change as a function of applied electric field and have found varieties of application in electronic and communication field. In this work, new data on the properties of BST characterize using the free space technique at frequencies between 145 GHz and 155 GHz for both thick film and bulk samples are presented. The measurement data provided useful information on effective permittivity and loss tangent for all the BST samples. Data on the material transmission, reflection properties as well as loss will also be presented. The outcome of the work shows through practical measurement, that BST has a high permittivity with moderate losses and the results also shows that BST has suitable properties to be used as RAM for high frequency application

Effect of different subsectional basis and testing function in the method of moments for the scattering from two dimensional dielectric scatterers

Different integral equations are reduced to a system of linear equations via method of moments (MoM) where the different basis and testing function utilised are sinusoid/pulse, sinusoid/sinusoid, sinusoid/triangle, triangle/pulse, triangle/sinusoid and triangle/triangle method. A hollow/layered dielectric cylinder has been taken as a representative case study. Comparison is made on the convergence and accuracy due to different testing function where the mean relative error is investigated numerically to show the essential differences of different basis and testing function in the MoM using different implementation techniques and different boundary conditions. The Gauss quadrature and staircase approximation technique is used in calculating the impedance matrix elements. The different boundary conditions utilised is the exact and impedance boundary condition. Numerical results points out to the need to investigate the performance of other basis and testing functions for dielectric scatterers

Contributions to forest and land fire prevention: a case of how the DMPA program strategic approaches in Riau Province / Nurul Huda, Salyani Osman and Azmuddin Ibrahim

Riau Province is one of eight provinces in Indonesia that are always faced with forest and land fires every year which impact health, economy, education, socio-culture, tourism, and the environment in Riau Province. This paper aims to discuss how the Desa Makmur Peduli Api (DMPA) Program's contribution was form ed by the Asia Pulp & Paper (APP) Sinar Mas company to minimize forest and land fires in Riau Province, especially fo r forests and land adjacent to APP Sinar Mas's concession areas. This article uses a case study as a research design. Case study research allows fo r an in-depth review of new or obscure phenomena while maintaining real-life events' holistic and meaningful characteristics. In this paper, the authors interviewed community leaders and activists of the Village of Makmur Peduli Api (DMPA) to explore the contribution of DMPA in preventing and overcoming forest and land fires in Riau Province. This paper's findings are that DMPA contributes to the prevention and control of Forest and Land Fires in Riau Province by the following methods: (1) changing the mindset and behavior of the community in clearing land by not burning. (2) Changing the people's mindset from initially cultivating tree crops to horticulture and other businesses such as fisheries (3). Increasing the community's economy.This paper concludes that Desa Makmur Peduli Api (DMPA) contributes to the prevention and control of forest and land fires in the Riau Province

Application of a monopole sensor for rapid in situ water quality assessment: theoretical analysis

This initial study proposes a rapid and cost effective in situ water quality assessment based on reflection coefficient of a 1.749 cm long bare monopole senor. The reflection coefficient of the monopole sensor in air, water and ethanol were studied from measurement and calculations of Finite Element Method (FEM). FEM was used to calculate the reflection coefficient of the sensor in water/ethanol mixture solution

Substrate specificity of lipases from four species of Aspergillus towards hydrolysis of homoacid triacylglycerols and vegetable oils in non-aqueous system

Among the four species of Aspergillus, Aspergillus oryzea lipase demonstrates high preference towards medium chain triacylglycerols (C10) and discriminates against triunsaturated triacylglycerol (TAG) e.g. triolein. The great discriminating power of its lipase against triolein was shown in comparison with its ability to catalyse the hydrolysis of medium chain (C10) TAG e.g. tricaprin and less shown when hydrolysing saturated long chain TAG i.e. tripalmitin. The discriminating power of these lipases are in this order: triolein > tripalmitin > trilaurin > tricaprin. Similar phenomenon was noted when mycelium-bound lipases of Aspergillus sp. were used to catalyse the hydrolysis of coconut oil, palm olein, olive oil and flaxseed oil. In most cases, relative percentage of monounsaturated fatty acid (C18:1) in non-hydrolysed fractions of oils increased after 12 days of hydrolysis. Hydrolysis of flaxseed and olive oil showed that Aspergillus murarum, Aspergillus oryzea and Aspergillus flavus lipases have high preference towards polyunsaturated fatty acids i.e. linoleic acid (C18:2) in olive oil and linolenic acid (C18:3) in flaxseed oil and no preference for monounsaturated and saturated long chain fatty acids

Tunable rectangular ring resonator filter with embedded shunt barium strontium titanate capacitors

Design of a low loss tunable bandpass filter using a microstrip ring resonator is presented. The tunability is achieved through the use of embedded shunt parallel plate variable capacitor implemented into the Low Temperature Cofired Ceramic (LTCC) substrate using thick film Barium Strontium Titanate (BST) paste. Measured data on the filter response, loss, and tunability in the frequency of 10 GHz and 12 GHz is presented. Results show filters produced low insertion loss with narrow tenability range

Extraction of essential oils from Zingiberaceace famili by using Solvent-free Microwave Extraction (SFME), Microwave-assisted Extraction (MAE) and hydrodistillation (HD)

Solvent-free microwave extraction (SFME) and microwave-assisted extraction (MAE) is a combination of dry and wet distillation with microwave heating. Both methods were compared with hydrodistillation (HD) for the extraction of essential oil from three types of rhizomes in Zingibereaceace family: Mango ginger (Curcuma amada), Java turmeric (Curcuma xanthorrhiza Roxb), and Black turmeric (Curcuma aeruginosa). Better results were obtained with SFME and MAE in terms of rapidity with 1 h extraction time using SFME and MAE vs. 4 h of extraction time using HD. SFME and MAE gives highest yield of essential oils at every second during the extraction process compared with HD

synthesis and characterization of hematite Fe2O3 nanofiller for enhanced dielectric and microwave-absorbing properties in PTFE composites

This paper presents the synthesis of hematite Fe2O3 nanofiller from mill scales and its application in polytetrafluoroethylene (PTFE) composites for enhanced dielectric and microwave-absorbing properties. The nanofiller was obtained through 9 hours of high-energy ball milling, resulting in a particle size reduction 43.6 to 11.05 nm. The PTFE/Fe2O3 composites were fabricated by dispersing different concentration of Fe2O3 nanofillers using the dry powder processing technique. The structural and morphological characterization of the nanofiller and PTFE/Fe2O3 composites was carried out using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. The composites’ microwave absorption properties were analyzed utilizing vector network analyzer (VNA) measurements in the 8–12 GHz frequency range. Based on the findings from the results, as the percentage of filler increased from 5 to 15%wt, the composites' loss tangent and dielectric constant increased from 0.0272 to 0.0478 and 2.12 to 3.25, respectively, while their reduced signal transmission speed was between 2.21 and 2.07 x 108 m/s at 8 GHz and from 2.24 to 2.11 x 108 m/s at 12 GHz. These findings demonstrate that Fe2O3 nanoparticles are a suitable material for developing microwave-absorbing polymer composites within the 8–12 GHz frequency range

Structural and magnetic properties of yttrium iron garnet (YIG) and yttrium aluminum iron garnet (YAlG) nanoferrite via sol-gel synthesis

The structural and magnetic properties of yttrium iron garnet (YIG) and yttrium aluminum iron garnet (Y3AlxFe5−xO12, YAIG) (x = 0.2, 0.6, 1, 1.4, 1.8, and 2.2) nanoparticles were investigated. The samples were prepared via auto combustion sol-gel technique, using citric acid as chelating agent and fuel for the combustion process. The obtained powder was heated at 950 °C. X-ray diffraction peaks confirmed the garnet phase formation. Crystallite size increases with Al from 28.5894 to 28.6170 nm. Lattice constant of the samples was found to decrease from 12.4674 Å to 12.3233 Å as Al increase from 0.0 to 2.2. FTIR was used to confirm the garnet structure, the main vibrating modes were observed to shift to higher wave number with increasing Al concentration. Saturation magnetization, Ms shows a decreasing trend from 20.721 to 0.7586 emu/g with increasing Al from 0.0 to 2.2. Furthermore, the decreasing trends in the static magnetic properties of YAIG samples may be due to the introduction of Al ions in the YIG crystal lattice. High content of Al substitution on YIG leads to paramagnetic behavior of the ferrite. The grain size decreased from 0.64 μm to 0.32 μm, while the bulk density decreased from 5.058 gcm−3 to 4.233 gcm−3 as Al increase from 0.0 to 2.2