Atom Indonesia (E-Journal)
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Nanostructure and Magnetic Field Ordering in Aqueous Fe3O4 Ferrofluids: A Small-Angle Neutron Scattering Study
Get PDFDespite the importance of reducing production costs, investigating the hierarchical nanostructure and magnetic field ordering of Fe3O4 ferrofluids is also important to improve its application performance. Therefore, we proposed an inexpensive synthesis method in producing the Fe3O4 ferrofluids and investigated their detailed nanostructure as the effect of liquid carrier composition as well as their magnetic field ordering. In the present work, the Fe3O4 ferrofluids were successfully prepared through a coprecipitation route using a central precursor of natural Fe3O4 from iron sand. The nanostructural behaviors of the Fe3O4 ferrofluids, as the effects of the dilution of the Fe3O4 particles with H2O as a carrier liquid, were examined using a small-angle neutron spectrometer (SANS). The Fe3O4 nanopowders were also prepared for comparison. A single lognormal spherical distribution and a mass fractal model were applied to fit the neutron scattering data of the Fe3O4 ferrofluids. The increasing carrier liquid composition of the fluids during dilution process was able to reduce the fractal dimension and led to a shorter length of aggregation chains. However, it did not change the size of the primary particles or building block (approximately 3.8 nm) of the Fe3O4 particles. The neutron scattering of the Fe3O4 ferrofluids under an external magnetic field in the range of 0 to 1 T exhibited in a standard way of anisotropic phenomenon originating from the nanostructural ordering of the Fe3O4 particles. On the other hand, the Fe3O4 powders did not show anisotropic scattering under an external field in the same range. Furthermore, the magnetization curve of the Fe3O4 ferrofluids and nanopowders exhibited a proper superparamagnetic character at room temperature with the respective saturation magnetization of 4.4 emu/g and 34.7 emu/g
Release of Radioactive Particulates into the Air during Forest Fire in Riau Province, Indonesia
Get PDFForest fires are annual problem during the dry season and become a biggest threat to forest resources in Indonesia. The forest fires release into the atmosphere large quantities of particulate matter and volatilized substances. The present study investigates effects of forest fire on air quality in the case of a radiological event of ashes from forest fires emissionsin Riau province during an intense forest fire season that occurred in 2015.Atmospheric aerosol samples were collected from Mayto December, 2015 using a large volume TSP (total suspended particles) sampler.Concentrations of radionuclidesin airborne particulate matter were measured by using gamma spectrometry.It was shown that the activity concentrations of 226Ra, 232Th and 40K ranged from 0.026 to 0.114 mBq/m3, 0.005 to 0.011 mBq/m3 and 0.99 to 5.64 mBq/m3, respectively. The activity concentrations of 137Cs in air was found lower than the minimum detectable activity of the gamma counting systems (MDA), except for July and September 2015. The result showed that the smokefrom forest fires contain radioactive particulates, which may have a potential health risk of population, and need to be considered in forest fire disaster. Inhaled smoke particles from forest fires may contribute to enhanced radiation doses to the general public.
Sediment Sources Analysis Using CSSI Method in Pasir Buncir Micro-watershed, Bogor, Indonesia
Get PDFThere is an increasing need for reliable information concerning the source of the suspended sediment transported by rivers. Such information is required both to design effective sediment and non-point pollution control strategies and to provide an improved understanding of erosion and suspended sediment transport within a watershed. In some situations, there are many developing methods of fingerprinting to determine the contribution of sediment sources via the streambed sediment. In this study, compound-specific stable isotope (CSSI) fingerprint has been used to determine sediment source contribution in Pasir Buncir micro-watershed, Bogor, West Java. CSSI method is a newly developed technique in sediment sources contribution determination. This new technique is considered to be a very accurate technique for identifying the sediment sources contribution, especially in a watershed that has relatively similar soil types. This technique has been applied to studying the sediment source contribution study in a watershed with three different land uses with mostly clay loam soil type. One sample from each of three different land uses was collected vertically from the 0-2 cm depth range. Streambed sediment from the nearest outlet from the micro-watershed was also collected. Soil and streambed sediment samples were analyzed for d13C of bulk organic carbon and CSSI contents. The d13C of bulk organic carbon and CSSI contents analysis showed that all the three different land uses (one-season crop, intercropping, and pine forest) contributed to streambed sediment; approximately 79.2 % was from cultivated land of one-season crop, 15.2 %from intercropping land, and 5.6 % from pine forest
Assessment of Ionizing Radiation Effects on the Hematological Parameters of Radiation-Exposed Workers
Get PDFLong-term exposure to low doses of ionizing radiation may adversely affect human cells and tissues of hospital radiation workers, especially peripheral blood cell count. Blood cell count analysis is a useful screening test in a routine medical checkup. A high or low blood cells count even in a healthy-looking subject leads to the suspicion of disease and it should prompt further investigations. This study was aimed to assess the effects of ionizing radiation on the hematological parameters of radiation workers at several governmental hospitals in Indonesia and correlation between years of employment and equivalent dose on one hand and the hematological parameters on the other. It included 74 medical radiation workers occupationally exposed to low doses of ionizing radiation at the Unit of Radiology and Radiotherapy and 83 controls. Fourteen hematological parameters were measured by ABX Micros 60 Hematology analyzer and the correlation between years of employment and equivalent doseas well as hematological parameters on radiation-exposed workers were tested by linear regression analysis test. Our study reported that red blood cell and monocyte counts were significantly higher in radiation-exposed workers compared to controls, whereas white blood cells, hematocrit, mean corpuscular volume, and lymphocytes values were significantly lower in radiation-exposed workers. A significant correlation was observed between equivalent dose and red blood cells (RBCs) parameter (P=0.001) with a decline in RBC level of 0.541×106/µL per 1 mSv increase of radiation dose. The present study recommends that further studies shoulduse a larger sample size and include various independent variables (genetic polymorphism, chromosome aberration, micronucleus frequency) to study the long-term effects of low-dose radiation exposure on radiation-exposed workers
The Effects of External Magnetic Field on the Physical Properties of La0.41Ca0.59Mn1-xCuxO3 with x = 0.06 and 0.15 in the Temperature Range of 100 – 300 K
Get PDFThis work investigated the crystal structure, resistivity and specific heat of La0.41Ca0.59Mn1-xCuxO3 with x = 0.06 and 0.15. The samples were prepared by a solid reaction method and in milling with high energy milling (HEM) of 700 rpm for ten hours. Neutron scattering with high resolution powder diffraction (HRPD) is used to analyze the phase and crystal structure. For resistivity analysis, four point probes are used, and SQUID Quantum Design is used for specific heat analysis in temperatures range of 100 - 300 K. In all cases, the sample has an orthorhombic crystal structure with a space group Pnma. The influence of a magnetic field on the specific heat and resistivity is also determined as a function of temperature. The resistivity increases in the presence of an external magnetic field. At the temperature less than 184 K, the resisitivity follows the Arhenius model (ln R varies as 1/T0.25) while at higher temperatures it fits the metal-semiconductor model (ln R varies as 1/T). The electronic specific heat parameter γ varies with magnetic field at x = 0.06, but not at x = 0.15
Occupational and Patient Doses in Interventional Cardiology in Indonesia: A Preliminary Result
Get PDFInterventional cardiology is a branch of cardiology that manages the catheter based treatment of structural heart illnesses. These minimally invasive procedures involve inserting catheters and other devices through superficial arterial and venous access sites. Due to increased reliability and advancing technology, the number and complexity of interventional cardiology procedures haves increased in recent years. The increasing complexity of the procedures, however, require longer fluoroscopic duration, leading to increased exposure time to ionizing radiation for the patient and also for the medical staff since they need to remain close to the patient throughout the procedure. This study attempts to investigate the occupational and patient doses during the course of several interventional cardiology procedures in Indonesia, i.e. CA, PCI, cathscan, PA, PTCA, TACE, PAC and peripheral vascular. Occupational doses were measured by using individually packed three chips of TLD-100 placed in over- and under-thyroid shield used by medical staff, over- and under-apron in waist position, inside a special ‘eye-D’ holder, and inside a ring holder, while patient doses were estimated by using individually packed three TLD-100 chips attached in the x-ray tube. All TLDs were calibrated in the Secondary Standard Dosimetry Laboratory (SSDL) Jakarta. The study was performed in three big hospitals in the cities of Jakarta, Yogyakarta and Semarang. The results show that PCI procedure was the most performed one during the course of this study and gave the highest radiation doses to the staff for all type of doses calculated and measured. The maximum effective doses, eye lens doses, extremity doses, thyroid doses and gonad/ovary doses were 0.098 mSv, 0.1967 mSv, 0.7604 mSv, 0.1760 mSv and 0.0990 mSv, respectively. In the case of patient doses, the mean value of DAP for PTCA procedure of 776.76 Gy cm2 was the highest compared with those for other procedures. The results of measurement for occupational doses were in general similar to those reported by other authors, but not for patient doses that was found to be 4-5 times higher. Due to the involving of various parameters during the course of interventional cardiology procedures, it was difficult to establish a correlation between the doses received by medical staff and by the patients
Spectral Comparison of Neutron-Irradiated Natural and Enriched Ytterbium Targets for Lu-177 Production
Get PDFBeta-emitting radioisotope 177Lu has been suggested for radioimmunotherapy, peptide receptor radionuclide therapy, or another radionuclide therapy due to its excellent properties for destroying cancer cells. In this experimental investigation, natural ytterbium (natYb) and enriched 176Yb targets were irradiated with thermal neutrons at 1.2×1014 cm-2s-1 neutron flux for 95 hours. Using a high-purity germanium (HPGe) detector-based spectroscopy system, the post-irradiated targets were measured and the produced radioisotopes were identified according to their gamma ray emissions. Experimental results indicated that several radioisotopes such as 169Yb and 175Yb dominate the post-irradiated natYb target, though a relatively weak intensity of 177Lu was also recorded. In contrast, 177Lu radioisotope dominates the gamma rays observed in the post-irradiated enriched 176Yb target following elution with HNO3 solution. For the first time, evidence is found of 175Yb impurity in the post-neutron-irradiated enriched 176Yb2O3 target as a result of 176Yb(n,2n)175Yb nuclear reaction. This work recommends future 177Lu radioisotope production using enriched 176Yb2O3 target
