The Method of CT Dosimetry Based on the CTDI (Computed Tomography Dose Index) for the Treatment of the Human's Head

The method of CT dosimetry based on the CTDI is a common measurement method by using a single, axial rotation about a pencil chamber in a stationary phantom. For some time now there has been a growing awareness that radiation dose originating from medical diagnostic procedures in radiology, is contributing an increasing proportion to the total population dose, with a large component coming from CT examinations. This is accompanied by rapid developments in CT technology, including the use of increasingly wide X ray scanning beams, which are presenting problems in dosimetry that currently cannot be adequately addressed by existing standards. When preparing any dosimetric assessment of a CT scanner it is essential to have a good knowledge of the production of X rays and the characteristics of the CT scanner. Factors that influence the X ray beam intensity and photon spectrum are the tube voltage, the anode material, and anode angle, the filtration of the X ray tube, and the tube current. The properties of the radiation field for CT dose considerations can be characterized by free in air measurements of air kerma (absorbed dose in air). Measurements in standard cylindrical phantoms yield dosimetric quantities such as CTDI that can be considered as a patient dose index, and are also useful for quality assurance purposes, however they should not be interpreted as patient dose

The Effect of Sintering TIME on Surface Morfology of Pb-Doped Bi-2223 Oxides Superconductors Prepared by the Solid State Reaction Methods at 840 OC

This study was investigating the effect of sintering time (30 h, 32 h, and 34 h) on surface morphology of PbdopedBi-2223 oxides of superconductors prepared by the solid-state reaction method at 840 oC. Thesuperconductor was characterized by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM).In the present study, phase purity, volume fraction, surface morphology, texturing, crystallinity, grainconnectivity and grain size of the bulk samples are found and compared with each other. The enhancementin the sintering time is confirmed that it will decrease Bi-2223 phase fraction and increase the impurity ofthe samples. SEM images shows that the sample has the best crystallinity, grain connectivity and largestgrain size. Based on the present results, it is conclude that the surface morphological is improving with theincreasing of the sintering time

Heat Energy of Candlenut Shell and Tamarind Skin Briquet with Variation on Particle Size and Pressure Pressing

Pemanfaatan limbah dari hasil perkebunan dapat digunakankan untuk pembuatan briket bioarang yang energinya dapat diperoleh sebagi energi alternatif. Pada penelitian ini dilakukan pembuatan briket bioarang campuran antara limbah tempurung kemiri dan kulit asam jawa dengan memvariasikan tekanan pengepresan (4 ton, 5 ton, 6 ton) dan ukuran partikel dari cangkang kemiri (20 mesh, 40 mesh, 60 mesh) untuk mengetahui kualitas briket yang dihasilkan. Hasil penelitian menunjukkan bawa nilai kalor briket bioarang tertinggi berada pada tekanan pengepresan 6 ton dengan ukuran butir 60 mesh sebesar 3350 kal dengan porositas sebesar 5,58 % dan kadar air sebesar 7,6 %. Farm waste utilization can be done by making a briquet as an alternative energy. In this research mixture of waste candlenut shell and tamarind skin as a briquet is studied by varying the pressure pressing (4 tons, 5 tons, 6 tons) and grain size of the candlenut shell (20 mesh, 40 mesh, 60 mesh) to determine the quality of briquettes resulting from. The results show that the highest heat energy of briquet currently on the pressing pressure of 6 tons with a grain size of 60 mesh at 3350 cal with a porosity of 5.58% and a water content of 7.6%

Synthesis and Microstructure Properties of (Bi,Pb)2Sr2Ca1Cu2Oy Ceramic Superconductor

Properties of (Bi, Pb)2Sr2Ca1Cu2Oy ceramic superconductors were prepared by the melt textured growth methods in order to investigate the effects of the slow cooling time on the microstructur. Phase analyses of the samples by X-ray diffraction (XRD) has been carried out to assess the effects of the slow cooling time. From XRD analyses, the addition to the sample of the slow cooling time degrades formation of the high-Tc Bi-2212 phase. The possible reasons for the observed degradation in the microstructure properties due to the slow cooling time addition were discussed

Gross Regional Domestic Product Forecasts Using Trend Analysis: Case Study Of Bangka Belitung Province

Gross Regional Domestic Product (GRDP) is one of the important indicators to determine the economic conditions in the region. This study aims to forecast the Gross Regional Domestic Product (GRDP) of the Province of Bangka Belitung Islands which is dominated by tourism sector. This forecasting to be expected to give information to formulate a type of policy action that will be conducted by decision makers based on GRDP data. GRDP data are from the first quarter of 2010 to the fourth quarter of 2017 on the basis of constant prices in 2010. Data sources are obtained from Central Bureau of Statistics (BPS) of the Province of Bangka Belitung Islands. The forecasting method used is the research is trend analysis. The results of the GRDP forecasting of Bangka Belitung Province in the first quarter of 2018 to the fourth quarter of 2022 shows an increasing trend. It can be seen from historical data that shows an increasing trend as evidenced from the graph on linear trends. The increasing trend in GRDP of the Bangka Belitung Islands Province for the next five years is supported by government policies that prioritize the tourism sector. Consequently, by prioritizing the tourism sector, this will increase economic growth and can reduce GRDP dependency on mining sector, especially tin that has been continuously decreased

Geographically Weighted Regression Principal Component Analysis (Gwrpca) Pada Pemodelan Pendapatan Asli Daerah Di Jawa Tengah

Linear Regression Analysis is a method for modeling the relation between a response variable with two or more independent variables. Geographically Weighted Regression (GWR) is a development of the regression model where each observation location has different regression parameter values because of the effects of spatial heterogenity. Regression Principal Component Analysis (PCA) is a combination of PCA and are used to remove the effect of multicolinearity in regression. Geographically Weighted Regression Principal Component Analysis (GWRPCA) is a combination of PCA and GWR if spatial heterogenity and local multicolinearity occured. Estimation parameters for the GWR and GWRPCA using Weighted Least Square (WLS). Weighting use fixed gaussian kernel function through selection of the optimum bandwidth is 0,08321242 with minimum Cross Validation (CV) is 3,009035. There are some variables in PCA that affect locally-generated revenue in Central Java on 2012 and 2013, which can be represented by PC1 that explained the total variance data about 71,4%. GWRPCA is a better model for modeling locally-generated revenue for the districts and cities in Central Java than RPCA because it has the the smallest Akaike Information Criterion (AIC) and the largest R2