The second order second stage stochastic Runge-Kutta method (RK2-2st) is implemented for solving stochastic point kinetic equations with Newtonian temperature feedback effects, taking into consideration external ramp reactivity. The feedback temperature is included in the reactivity; it is an entry variable of point kinetic equations. Doppler feedback in thermic reactors is mainly due to epithermal capture resonances in non-fissionable combustible isotopes. Different numerical experiments have been carried out in which calculations are made of reactivity, mean values and standard deviation of neutron density, and the concentration of delayed neutron precursors. The results obtained are compared with other methods reported in literature, and it is found that the method proposed is sufficiently precise to give a solution to the stochastic point kinetic equations of an adiabatic reactor.

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In this article is presented the design and implementation of a prototype detector antipersonnel mines using neural networks and fuzzy logic, supported by the metal detector Garrett ACE 250. This prototype generates a signal source, which is amplified both voltage and current and entered to the primary winding of the sensor. When the emitted signal collides with a metallic object is returned to the sensor and becomes the signal to be processed. The offset angle is used to determine the type of metal and the approximate distance to which the detected object is located. Using a graphical interface in Matlab in real time the signal is shown to the user. As a result, a discriminator prototype metals, programmed in Matlab and the graphical user interface are obtained. The prototype was validated by experimental field testing and a better result was achieved with fuzzy logic achieving the expected discrimination of the types of metal used and the distance at which they are found.

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The construction systems of the retention structures usually used for stabilizing excavations have technical restrictions in areas with the presence of large rock blocks. A similar situation is experienced in projects where the slope of the terrain makes access and location of large mechanical equipment difficult. Therefore, the most widely used system in the construction of these structures is restricted to manual excavation methods. Such methods, in addition to being expensive, require long execution times and considerable uncertainty within the construction schedule. Based on the construction limitations presented by traditional earth retaining systems (RS), this research proposes to carry out a technical evaluation of an alternative retaining system. This alternative consists of a wall constructed from steel pipes injected with grout and strutted with prestressed anchors (RS-2). For this evaluation, it is proposed to elaborate a numerical modeling of the RS-2 for different vertical separations between elements, and to compare these results with the behavior registered in the field during the construction of a typical earth retaining system in the Valle de Aburrá (Medellín, Colombia); where a reinforced concrete wall strutted with active anchors (RS-1) was employed. This research establishes the technical feasibility of a retaining system built from steel pipes as an alternative earth retaining system. Its feasibility was sustained after verifying that the safety factor found for RS-2 retaining systems was greater than the required safety factor; in addition, the RS-2 retaining system presented deformations similar to those registered in the field, during the construction of a traditional retaining systemRS-1.

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In this research modified rice straw (MRS) was prepared. The proposed production process of the modified rice straw (MRS) adsorbent is carried out by precipitation of iron nano particles on the surface of acid activated rice straw. The nitrate adsorption is carried out through batch experiments. The optimum nitrate removal 94.8 % was achieved at Ph = 7, adsorbent dose 3 = g/L, 150 rpm, initial nitrate concentration = 23 mg/L and contact time 180 = min. The new adsorbent synthesis, kinetics and isotherm models were studied. The nitrate adsorption was well described by pseudo second order kinetic model (R2 = 0.999) as it fitted with the experimental results better than the pseudo first order kinetic model (R2= 0.872). The rate limiting step was determined using intraparticle diffusion model and Byod plot. For two parameters isotherm model; Freundlich and Halsey isotherms (R2 = 0.997) fitted with the experimental results better than Langmuir isotherm model (R2 = 0.973).For three parameters isotherm; Koble-Carrigan isotherm and Langmuir-Freundlich isotherm (R2 = 0.9999) fitted with the experimental results better than Redlich-Peterson model (R2 = 0.5).

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Standard Metropolis Monte Carlo (S-MMC) simulations allowed us to calculate magnetization as a function of temperature and magnetic field, for theLa0.66Ca0.33Mn(1-x)4+FexMn3+O3(x=0, 5, 10, 20 and 30 %)(LCMFx) compound. The respective critical exponents for M(T), H/M(H) and M(H,T=Tc) close to the critical temperature, were calculated using the Arrott plot (AP). The values of the critical exponents evinced a type of magnetic universality present in this type of material. The results of the simulation leads us to believe that there is a correlation between the displacement of the magnetic transition temperature (ferromagnetic-paramagnetic), which is characterized by the Curie temperature and an increased percentage of iron present in material. On the other hand, the model determines a value of the critical temperature and this is correlated to the number of Monte Carlo Steps (MCS). For a number of MCS of the order of 102, the system tends to relax with the transition temperature which depends on the percentage of iron. By comparing the Tc values determined based on the two methodologies M(T) and AP, we can see that, the greater percentage of iron in the material, the more distance between the two trends. Based on these results, it is possible to infer that the increased percentage of Fe increases the presence of effects in the material that lead to an increased variation of the magnetic anisotropy.

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Blasting simulation methods are essential for the success of all projects for reaching proposed objectives and minimizing risks. In the following research, it was made a study of case of a blasting made under San Carlos´ Bridge in Antioquia, Colombia, with the purpose of protecting the stapes using detonating cord as a fund delay and Emulind S explosive, analyzing vibration data with O-PITBLAST cell phones and correlating the design to the rock mass. It was used the PPV method or attenuation law and consequently, data obtained by the equipments were simulated. It was possible to conclude that the vibrations taking have the effectiveness for predicting and mitigating risks, not only for the project, but also for nearby buildings. Likewise, it was determined that drilling must be parallel to diaclasas with trained and experimented staff. Also, the detonating cord as fund delay causes a shotgun effect in the basin. Limitations of the following study are based principally in the ignorance of geology and geotechnics in the testing place, and its possibility of including these variables in the development of the project.

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The successfully synthesis of Zn/Al, Zn/Cr layered double hydroxides (LDH) intercalated with Keggin ion [a-SiW12O40]4- were confirmed by XRD, BET, and FT-IR analyses and used as an adsorbent Cadmium (II). The adsorption process was investigated by studying pHpzc, the kinetics, and thermodynamic properties of the adsorption process. The results showed the interlayer of Zn/Al and Zn/Cr after intercalation were increased to 10.26 Å and 10.35 Å from 7.51 Å and 7.53 Å, respectively. BET analysis represents after intercalation surface area was increased five times bigger than pristine LDH. The pore classification is mesopore. pH point zero charge shows the materials has pH 6-8. LDH intercalated with Keggin ion [a-SiW12O40]4- has higher adsorption capacity than pristine. The reusability study show the effectiveness of adsorbent.

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In this work two model-based controllers have been designed in order to regulate a non-linear system of coupled tanks. First, a Proportional-Integral-Derivative (PID) controller was designed. This algorithm requires a linear model, so the model was linearized around a certain equilibrium point. Secondly, Internal Model Controller (IMC) was designed. Finally, the performance of the controllers is evaluated, in order to carry out a tracking to a reference level and an effective rejection of the disturbances.

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In this paper we consider the numerical calculation of the values of the axial and plane components of the magnet-ic field of a three-dimensional ring with a current. The magnitude and direction of the magnetic induction vector is determined depending on the coordinates along the axis and in the plane of the ring. A formula for the planar com-ponent of the magnetic field of a three-dimensional ring with a current is obtained by numerical calculations. The results of experimental measurement of the magnetic field using a Hall sensor are presented and their good agree-ment with numerical calculations is shown.

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Gravity method is one of the methods in geophysics that involves measuring the earth’s gravitational field at specific locations on the surface of the earth. It is used to determine the subsurface properties according to anomalies which indicate density variations. The main objective of this study is to determine subsurface geological properties in Perak, Malaysia using satellite acquired corrected gravity anomaly data obtained from Earth Gravitational Model 2008 (EGM2008). With the aid of Oasis Montaj, a software by Geosoft, the data from 296225 station points are used to produce Bouguer Anomaly map. By comparing the Bouguer Anomaly map produced with the geological map of Perak, three zones can be determined from the anomaly value which are high, intermediate and low. High anomaly zone (> 10 mGal) can be seen on Quaternary rocks due to the influence of high density oceanic crust. Intermediate anomaly zone (-10 to 10 mGal) can be seen on Palaeozoic rock formation. In this zone, low value can be seen on rocks closer to granite formation and higher towards oceanic crust. Low anomaly zone (<10 mGal) can be seen on areas with granitic body due to isostatic compensation. From the GYM-Sys filter of the Oasis Montaj software, two estimated two dimensional gravity model is produced from two lines (A-B) and (B-C) drawn on the Bouguer Anomaly map. These models were deduced based on the formation information provided by past researches.

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The most promising direction in the modification of aluminum alloys, including silumins, is the use of ultrafine modifiers (carbon nanoparticles, ultrafine carbides, nitrides, oxides, etc.) with a particle size of 0.1-1 µm, which can improve the quality of alloy with minimal implementation costs. According to the results of the work done, it was found that the technology for modifying silumin based on primary aluminum with high iron content by a tablet modifier leads to a change in the morphology of the ß-phase. This allows increasing the elongation of the alloy by 50 % and the ultimate tensile strength by 20 %.

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Using a large number of variables in regression modeling might lead to a serious collinearity problem. Ordinary least square produces a very large bias and mean squared error of the parameter estimates and prediction. Several methods have been proposed to overcome collinearity problem such as a ridge, principal component, and partial least square regressions. Ridge regression is a method commonly used. Ridge regression method can be modeled using several ways such as classical, Bayesian, and machine learning. Our study has evaluated those methods to find the best method that can be used to overcome the collinearity problem. Apparently we observed the ridge regression by means machine learning method is the most powerful method. It has a minimum bias and mean squared error of the parameter estimates and minimum residual. This method provides an algorithm called gradient descent. Gradient descent can be used to estimate the optimum regression parameter by minimizing the cost function (reached the steepest descent). Thus the value of this function will update the previous parameters and it will give us the best model of the dataset.

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This paper presents a method to correct the values of the mass fractions of saturates, aromatics, resins and asphaltenes (SARA analysis) of dead crudes by adding the dissolved gas to the saturated fraction of SARA analysis. This paper also shows the procedure to obtain the necessary equations to correct each fraction from the volumetric gas/crude ratio (Rs). Four hypothetical crudes were analyzed to calculate the different mass ratios. The SARA analysis of 27 Colombian crudes was performed and the incidence of dissolved gas was determined in the calculation of live crude SARA. The change in the saturated fraction was between 2 and 22% for Black Oil and between 14 and 74% for Volatile Crude Oil. Furthermore, a modification of the “Colloidal Instability CII Index” is presented, and the values obtained by this new methodology are compared to this index.

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In the Internet of medical things (IoMT) and big data era, medical image compression is crucial in today’s world. Importantly, compression of large sized medical images is required for everyday tasks, including, storage space utilization and transmission bandwidth of healthcare systems and internet transmissions. However, in this paper, Modified Run Length Encoding (MRLE) is applied as a lossless compression and fast technique to compress medical images. RLE is applied to further increase the compression factor. The goal of using RLE is to enhance the compression factor without adding any distortion to the resultant decompressed image. Since, in healthcare systems and medicine applications, it is necessary to obtain high quality of the decompressed image. Moreover, MRLE is used to enhance the original RLE algorithm. The Block-Block scanning technique will be applied. Thus, this technique produces high efficiency compared with previous RLE techniques. The medical image is divided into equivalent blocks, where, the pixels inside each block are either scanned vertically or horizontally and all blocks together are also scanned vertically or horizontally. In the produced vector, the similar run of the same pixels' value will merge to reduce the size of the output vector. Importantly, the results of the proposed algorithm are shown to be comparable in quality and performance with other existing medical image compression methods.

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This document presents the design and implementation of a wireless system to measure water quality parameters in rivers, using low-cost elements for its implementation. Modules LoRa is used for communication between nodes, which is a technology that has emerged with the increase of wireless sensor networks (WSN), the Internet of Things (IoT) and machine to machine communication (M2M). The LoRa modules have great characteristics due to their low power consumption, taking into account the distances they can cover and their low cost. Sensor nodes are built to monitor the following parameters: electrical conductivity, pH and temperature, plus a receiver node that is connected to a computer to display the data received through a graphical interface made in Java.

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The radiation exposure from standalone CT in neck area might increase the thyroid cancer risk particularly in paediatric. The aim of this study is to characterize the dose received by adult and paediatric thyroid undergoing CT examination in the neck region. Two sets of Thermoluminescent dosimeters (TLD) and Optically Stimulated Luminescent Dosimeters (OSLD) were installed into a solid 3D thyroid phantom of adult and 10 years old paediatric patients, to measure the thyroid dose during neck scanning in DECT. The displayed dose quantities on the CT workstation were used for effective dose evaluation in the thyroid. In addition, CT-Expo software was used for verification purposes. The CTDIvol was very close to the absorbed dose from dosimeters inside the thyroid phantoms. The study reveals that the risk of collecting cancer later in life in the thyroid from the common CT scans in neck area is up to 192 per million children. The number is considered as low, but should not be ignored, while CT scans procedures are increasing every day.

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