Atom Indonesia (E-Journal)
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An Online Non-Invasive Condition Monitoring Method for Stepping Motor CRDM in HTGR
Get PDFControl Rod Drive Mechanism (CRDM) based on stepping motor is one of the components applied in High Temperature Gas Coold Reactor (HTGR) to control the reactivity as well as to maintain the safety of reactor. The stepping motor requires a unique condition monitoring to avoid any failures especially due to the specific environments of CRDM in HTGR such as the allowable of high temperature, high radiation and the location of stepper motor inside a pressure shell. This research aims to demonstrate an online non-invasive condition monitoring method without direct access to the CRDM of HTGR based on voltage and stator current measurements. A simple stepping motor CRDM simulator is employed. The online condition monitoring is carried out by direct pattern matching of the output signals of logic generator block and the output signals of motor driver. The online method utilizes signature patterns of voltage and stator current signals of the healthy motor as a baseline for healthy motor. In addition, the method is applied to detect high-resistance problem on the connector between the motor driver block and the stepper motor to show the effectiveness and the applicability of this method. The online condition monitoring system demonstrates a capability to identify a minimum detectable simulated high-resistance for about 2.9% which decreases the measured stator current and motor’s torque for around 5.1% and 3.3%, respectively. The paper also points out signatures of healthy motor, including mutual inductions of the motor’s winding in voltage and current measurement which can be used as the fault symptom indicators for online monitoring purposes.Received: 19 November 2014; Revised: 13 April 2016; Accepted: 22 June 201
Temperature and Salinity Effects on Bioaccumulation, Gill Structure, and Radiation Dose Estimation in the Milkfish Chanos chanos Exposed to 137Cs
Get PDFThe present trend of global warming has led to an increase in seawater temperature and salinity. The effects of increasing salinity and temperature on the accumulation of 137Cs by milkfish Chanos chanos was studied under laboratory conditions to obtain information on Chanos chanos adaptability under environmental changes. The uptake of radioactive cesium by Chanos chanos increased with temperature of seawater. The concentration factors (CF) of 137Cs for temperatures of 25°C, 27°C, 29°C, and 31°C at steady state period were 5.25, 5.91, 6.78, and 9.98 mL g-1 for the whole-body of Chanos chanos. The concentration factors at steady state (CFss) of 137Cs for salinities of 26‰, 29‰, 32‰, and 35‰ were 6.23, 9.93, 9.24, and 6.86 mL g-1, respectively. After temperature exposure to 31°C, the fish gills showed hyperplasia of epithelial cells in branchial secondary lamellae, congestion of blood vessels, and hypertrophy of pillar cells. The fish from the treatment group exhibited hemorrhage between the branchial secondary lamellae and an abundance of mucous substance in comparison with control group. This study links radionuclide bioaccumulation data and monitoring data obtained in the field and laboratory experiment with radiation dose determined by ERICA Tools, an approach that will enable better linkages to be made between exposure and dose in Chanos chanos and its marine food web.Received: 2 November 2015; Revised: 1 July 2016; Accepted: 17 July 201
The Utilization of Microbial Inoculants Based on Irradiated Compost in Dryland Remediation to Increase the Growth of King Grass and Maize
Get PDFThis research was conducted to evaluate the capability of functional microbial inoculants to remediate drylands. The microbial inoculants used consist of hydrocarbon-degrading microbial inoculants and plant-growth-promoting microbial inoculants. Compost-based carrier was sterilized by a gamma irradiation dose of 25 kGy to prepare seed inoculants. The irradiated-compost-based hydrocarbon-degrading microbial inoculants and king grass (Pennisetum purpureum Schumach.) were used to remediate oil-sludge-contaminated soil using in-situ composting for 60 days. The results showed that they could reduce THP (total petroleum hydrocarbons) by up to 82.23%. Plant-growth-promoting microbial inoculants were able to increase the dry weight of king grass from 47.39 to 100.66 g/plant, N uptake from 415.53 to 913.67 mg/plant, and P uptake from 76.52 to 178.33 mg/plant. Cow dung and irradiated-compost-based plant-growth-promoting microbial inoculants were able to increase the dry weight of maize (Zea mays L.) from 5.75 to 6.63 ton/ha (12.54%) and dry weight of grain potential from 5.30 to 7.15 ton/ha (35.03%). The results indicate that irradiated-compost-based microbial inoculants are suitable for remediating a dryland and therefore increase potential resources and improve the quality of the environment.Received: 17 March 2015; Revised: 28 October 2015; Accepted: 28 October 201
ENC Measurement for ASIC Preamp Board as a Detector Module for PET System
Get PDFWe developed a gamma ray detector with an LuAG:Pr scintillator and an avalanche photodiode as a detector for a positron emission tomography (PET) system. Studies have been performed on the influences of gamma irradiation on application-specific integrated circuit (ASIC) preamp boards used as a detector module. As a device used in nuclear environments for substantial durations, the ASIC has to have a lifetime long enough to ensure that there will be a negligible failure rate during this period. These front-end systems must meet the requirements for standard positron emission tomography (PET) systems. Therefore, an equivalent noise charge (ENC) experiment is needed to measure the front-end system's characteristics. This study showed that minimum ENC conditions can be achieved if a shorter shaping time could be applied. Received: 22 October 2014 ; Revised: 23 Februari 2016; Accepted: 3 March 201
Evaluation of Mungbean Mutant Lines to Drought Stress and Their Genetic Relationships Using SSR Markers
Get PDFDevelopment of mungbean cultivarstolerant to drought stress through mutation breeding approach would enable us to anticipate the crop yield-reducing effects of climate changes. The objective of this research was to evaluate the yield performance of mungbean mutant lines that showed tolerance to drought stress, and to analyze their genetic diversity and relationship among mutant lines using SSR markers. The study was conducted during the dry season of 2012 in the Muneng experimental farm, Probolinggo, East Java. The experiment was laid out in a randomized block design with four replications. Five mutant lines and two parental lines as control were tested for evaluation of yield and drought tolerance under twoenvironments of two irrigation systems as treatment. The two environmental conditions consisted of optimal irrigation (at least three times: at planting, flowering and during pod filling) and suboptimal irrigation (two times at planting and flowering). To evaluate genetic variation among selected mutant lines and their discrimination from parental lines in molecular level, a cluster analysis was performed using Unweighted Pair Group Method with Arithmetic Mean (UPGMA) in the NTSYS software. The results showed that three mutant lines, including PsJ30, PsJ31, PsJ32 produced the highest grain yields of 1.17, 1.01, and 1.04 ton/ha, respectively, compared to the other mutant lines and the parents Gelatik (0.85 ton/ha) and Perkutut (0.87 ton/ha) as control check. Of those mutant lines, PSJ31 was the most tolerant to drought with sensitivity index value of 0.47. The PSJ31 has now been officially released as a new variety ( 2013), named as Muri which was identified to have high yield and tolerant to drought. Based on 23 SSR markers used for clustering analysis of those 3 selected mutant lines,9SSR markers (MBSS R033; satt137; MBSSR008; MBSSR203; MBSSR013; MBSSR021; MBSSR016; MBSSR136; and DMBSSR013) were successfully identified the three mungbean mutant lines. Taken together, we have succeeded at develop and evaluate three elite mutant breeding lines which are valuable resources for genetic variation in mungbean. The genetic variation information of mungbean at molecular level potentially provides room for recombinants which are essential for the development of a new superior variety in mungbean improvement.Received: 04 October 2014; Revised: 04 June 2015; Accepted: 16 June 201
The Relationship between Expression of p70s6k with Radiotherapy Response in Cervical Cancer
Get PDFThere are many important prognostic factors in advanced stage cervical cancer primary treated with radiotherapy. Besides clinical factors, many biomarkers have been studied in relation with radiotherapy response. The p70s6k is a biomarker which plays a significant role in cell proliferation. Increased levels of p70s6k are also associated with drug resistance in cancer. In the present study, the relationship between the expression level of p70s6k before treatment and the radiotherapy response in cervical cancer was determined. Immunohistochemical staining of p70s6k, MIB-1, and p53 was conducted in microscopic slide from 21 cancer tissue biopsies before treatment with radiotherapy. After the treatment had completed early radiotherapy response was observed by pelvic control method. The results showed that p70s6k is partly highly expressed (61.9%, 13/21) and partly low expressed (38.1%, 8/21) in the cancer cells. They also show that there is no statistically significant differences on AgNOR mean, MIB-1, and p53 indices in the different degrees of p70s6k expression (p≥0.05). Higher expression levels of p70s6k is more strongly associated with good radiotherapy response compared to lower ones (p=0.05). In conclusion, the level of p70s6k expression before treatment has an association with radiotherapy response
A Backward Method to Estimate the Dai-ichi Reactor Core Damage Using Radiation Exposure in the Environment
Get PDFThe Fukushima accident resulted in the melting of the reactor core due to loss of supply of coolant when the reactor stopped from operating conditions. The earthquake and tsunami caused loss of electricity due to the flooding that occurred in the reactor. The absence of the coolant supply after reactor shutdown resulted in heat accumulation, causing the temperature of the fuel to rise beyond its melting point. In the early stages of the accident, operator could not determine the severity of the accident and the percentage of the reactor core damaged. The available data was based on the radiation exposure in the environment that was reported by the authorities. The aim of this paper is to determine the severity of the conditions in the reactor core based on the radiation doses measured in the environment. The method is performed by backward counting based on the measuring radiation exposure and radionuclides releases source term. The calculation was performed by using the PC-COSYMA code. The results showed that the core damage fraction at Dai-ichi Unit 1 was 70%, and the resulting individual effective dose in the exclusion area is 401 mSv, while the core damage fraction at Unit 2 was 30%, and the resulting individual effective dose was 99.1 mSv, while for Unit 3, the core damage fraction was 25% for an individual effective dose of 92.2 mSv. The differences between the results of the calculation for estimation of core damage proposed in this paper with the previously reported results is probably caused by the applied model for assessment, differences in postulations and assumptions, and the incompleteness of the input data. This difference could be reduced by performing calculations and simulations for more varied assumptions and postulations.Received: 30 October 2015 ; Revised: 29 March 2016; Accepted: 31 March 201