Nor Zakiah Yahaya

A Simple Insulated Monopole Sensor Technique for Determination of Moisture Content in Hevea Rubber Latex

This paper describes the application of a SMA stub contact panel as an insulated monopole sensor for determination of moisture content in hevea rubber latex. Comparison results between measured and calculated reflection coefficient using King’s model are presented. Calibration equations relating moisture content to phase shift have been established in the frequency range from 100 MHz to 5 GHz. The accuracy of the technique was 1.3% when compared to actual moisture content obtained using the gravimetric method.

Intercomparison of Methods for Determination of Resonant Frequency Shift of a Microstrip Patch Antenna Loaded with Hevea Rubber Latex

This paper presents an intercomparison between the finite element method, method of moment, and the variational method to determine the effect of moisture content on the resonant frequency shift of a microstrip patch loaded with wet material. The samples selected for this study were Hevea rubber latex with different percentages of moisture content from 35% to 85%. The results were compared with the measurement data in the frequency range between 1 GHz and 4 GHz. It was found that the finite element method is the most accurate among all the three computational techniques with 0.1 mean error when compared to the measured resonant frequency shift. A calibration equation was obtained to predict moisture content from the measured frequency shift with an accuracy of 2%.

Comprehensive study of electronic polarizability and band gap of B2O3–Bi2O3–ZnO–SiO2 glass network

Quaternary glasses were successfully fabricated using melt quenching technique based on the chemical compound composition (x)Bi2O3–(0.5−x) ZnO–(0.2)B2O3–(0.3)SiO2, where (x=0.1, 0.2, 0.3, 0.4, 0.45) mole. The sources of SiO2 was produced from rice husk ash (RHA) at 99.36% of SiO2. The Urbach energy was increased from 0.16eV to the 0.29eV as the mole of Bi2O3 increased in the glass structure. The indirect energy band gap is indicated in decrement pattern with 3.15eV towards 2.51eV. The results of Urbach energy and band gap energy that were obtained are due to the increment of Bi3+ ion in the glass network. The refractive indexes for the prepared glasses were evaluated at 2.36 to 2.54 based on the Lorentz–Lorentz formulation which correlated to the energy band gap. The calculated of molar polarizability, electronic polarizability and optical basicity exemplify fine complement to the Bi2O3 addition in the glass network. The glass sample was indicated in amorphous state.

Analysis of Uranium concentration on maternal and umbilical cord blood samples after delivery in Iraq

Uranium is a naturally occurring radioactive and toxic element. An increased prevalence of birth defects was allegedly reported in Iraq in the post 1991 Gulf War period, which was largely attributed to exposure to depleted Uranium used in the war. This study is done to determine the concentrations of Uranium radioactivity in maternal blood and umbilical cord blood samples after delivery in hospitals in governorates of Baghdad, Dhi-Qar and Basrah in Iraq. A number of 100 pregnant women were involved; consist of 53 women delivered with normal and alive infants and another 47 women delivered with abnormal and dead deformed infants. The CR-39 detector is used to determine the Uranium concentrations found in the blood samples of maternal blood and umbilical cord blood. Results show that mean Uranium concentration for maternal and umbilical cord blood samples of deformed and dead infants is nearly double than the value of normal and alive infants. The older pregnant women were found to have greater Uranium concentration compared to younger pregnant women. Among the selected 3 governorates, pregnant women in Basrah shows the highest Uranium concentration on maternal and umbilical cord blood samples. High Uranium concentrations found in maternal and umbilical cord blood samples have caused the increased rate of mortality on infant and children in Iraq. Thus, precautions and awareness should be taken up seriously in order to improve the health condition and well being of the maternal and children, and thus for future generations in Iraq.

Fetal biometry assessment of biparietal diameter for Saudi Arabia population and comparison with other countries

In this study, a new reference range of biparietal diameter (BPD) is developed based on Saudi Arabia population. A number of 2075 pregnant women who attend the maternity check up in 2013 to 2015 at Department of Obstetrics and Gynecology, Hospital Maternity and Children of Dammam, Saudi Arabia, were involved in this study. The data were recorded from 12th to 40th weeks of gestational age (GA). The BPD was measured using Sony Corporation 1-7-1 Konan Minator-K. On-screen caliper is used to measure the BPD parameter on the frozen image using linear method. The SPSS software version 22.0 was used for analysis, with statistical analysis were performed such as compare means, regression analysis and paired sample t-test. Results show that higher BPD growth rate was found in second trimester (12th to 25th weeks of GA) with 2.90 mm/week compared to third trimester (26th to 40th weeks of GA) with only 1.68 mm/week, proved that the rapid growth of fetus head in second trimester than third trimester. Further analysis on maternal age, number of gravid and gender of the fetus were found no significant impact on the BPD values (p values ≥ 0.05). The BPD value of this study shows no significant difference with the BPD values of USA [1], Norway [2], Australia [3], Zimbabwe [4], India [5], China [6] and Malaysia [7]. Thus, this new BPD values are highly recommended to be used by the medical practitioner as the reference range of fetus biometry for Saudi Arabia population, in regards to provide a better healthcare and well being of the maternal and fetuses.

A simple rectangular microstrip technique for determination of moisture content in Hevea rubber latex

A simple rectangular microstrip sensor for determination of moisture content in Hevea Rubber Latex is presented in this paper. The microstrip patch sensor was designed to operate at microwave frequency range from 1 to 5 GHz on a RT/Duroid substrate with 6.15 ±0.015 permittivity and 1.27 mm thickness. The width and length of the rectangular patch antenna was 18 mm and 38 mm, respectively. The reflection coefficient of the sensor loaded with Hevea latex at various percentages of moisture content from approximately 36.1% to 88.6 %. Calibration equations have been established between moisture content and phase of reflection coefficient at several selected frequencies. These equations were used to predict the amount of moisture content on Hevea latex based on the measured reflection coefficient values. The actual values of moisture content were obtained using standard oven drying method. The lowest mean relative error between actual and predicted moisture contents was 0.04 at 1 GHz.