Sedimentation in the Mentawa river has increased from year to year, thus also the scouring of river banks which results in changes in the basic characteristics of the channel. The study was conducted to determine the differences between suspended sediment transport and bedload sediment transport in upstream, middle and downstream rivers, as well as bedload sediment transport capacity based on the amount of flood discharge. By measuring river variables in the field and using several methods to obtain sediment transport discharge, the EDI method for suspended sediment transport, while for bedload sediment are used MPM and Einstein methods, with a return period of rainfall 1, 5 and 25 years to get the bedload transport discharge. Results with the EDI method yielded sediment suspended in the upstream, middle and downstream sections respectively 0.0003, 0.0004 and 0.0009 m3/s, while for the bedload sediments the MPM method was 0.1607, 0.1071, 0.2156 m3/s, and the Einstein Method yielded 0.0680, 0.0080 and 0.1192 m3/s. The steeper the volume of sediment deposits the smaller, the volume of sediment means is directly proportional to the slope of the river.

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In this work, the asynchronous impulsive noise present in electric lines is characterized. This noise is used as communications media -PLC- which is stochastic by nature and turns detection into a complex matter. In first place, it is determined how to carry out the detection of aperiodical noise and the conditions in which it must be detected and the measuring environment, the selection of linear and non-linear loads and the measuring equipment are also discussed. The algorithms used to process the information are also implemented. The detected impulsive noises are Burst type since they are the most critical in an electric line communication system. Said noises were predicted using statistical processes and characterized using the Middleton model. A proposal was stated to detected aperiodic noise and, hence, a testing system was implemented in a household with several appliances in different states such as connection, disconnection, turn on, turn off, etc. The results are favorable and two types of aperiodic noise were found: type 1, whose first impulse is high but is diluted over time and the Burst type that corresponds to an oscillation with a specific frequency which is maintained during a period of time as indicated in the classification of aperiodic noise.

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Natural gas with acid gases (H2S, CO2, and organic acids) transported in the pipeline leads to a corrosion process and produces sludge accumulated in the pipe. This study was devoted to understanding the corrosion of API 5L X65 pipelines by examining the resulting sludge. The collected sludge was then treated and dried to become powder. Subsequently, the powder was subjected to XRF, XRD and SEM-EDX analysis for experimental material characterization. The obtained sludge contains major elements of Fe, Ca, Mn, and S according to the XRF analysis, while the resulting particle shape was in the form of rounded, irregular aggregates with a size of 8.427 µm and 6.775 µm while EDX results show the most chemical composition of specimens corresponding to elements of Fe, C, and O. The XRD Rietveld method confirmed that magnetite (Fe3O4) is the main crystalline mineral found in the corrosion product, while some minor products (e.g.CaCO3, FeCO3, and FeS) could be not detected under detecting limit of x-ray diffraction study. Evidently, the pipelines of API 5L X65 had been subjected to mainly CO2 corrosion, but a further assessment of this mechanism is still needed for a failure prediction and corrosion protection program of pipelines.

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This study uses the Fast Fourier Transform method for the calculation of reactivity; this method approximates the integral of the inverse point kinetic equation as a product of convolution between the neutron population density and the function of the unitary impulse that depends on the physical constants of the system. Considering that the reactivity values are caused by fluctuations in neutron density, these fluctuations can be simulated with a Gaussian distribution around an average value for neutron density. The exponential filter is used by means of a least squares adjustment for reducing the aforementioned fluctuations.

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The analysis of Mercury (Hg) in the water, sediment, and biota collected from the watershed area of Krueng Sabee (KS), Panga (P) and Teunom (T) has been conducted. Hg concentration was determined using Atomic Absorption Spectrophotometer. Meanwhile, the water pH, temperature, and salinity were determined with in-situ method. The in-situ determinations suggest that the qualities of KS, P and T waters are still under the standard threshold. Based on the analysis, the highest Hg concentration was found during the dry season, specifically in the sediment samples from the upstream area of River Krueng Sabee. On contrary, the lowest concentration was found during the rainy season, in the sediment samples from River Teunom. The evaluation of Hg distribution pattern in the water, sediment, and biota was conducted with Principal Component Analysis (PCA). It suggests the strong correlation between Hg concentration in the sediment with the one in the water and biota.

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The development of optical fibers from attenuation and absorption of fiber material for efficiency and quality has produced several positive results. However, several natural negative factors and environmental errors cause problems such as birefringence and dispersion mode variations. This article therefore proposed a simulation of birefringence and polarization mode dispersion (PMD) to investigate the emergence of interference and efforts towards finding a solution to the problem of optical fiber. Moreover, a single-mode fiber was investigated at the core refractive index and cladded with a core radius and fixed sample for a wavelength of infrared regimes. The performance of fibers was also evaluated through the determination of the PMD value of the fibers. The simulation results showed the difference observed in birefringence produced the power affecting the output. Meanwhile, the PMD also produced the light waves discovered to be experiencing widening pulses in the cladding.

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The article presents the development and optimized system for feed dosage for alevines, which is immersed in three areas of electronic engineering: telemetry, physical variables for the remote measurement, such as the percentage of dissolved oxygen and water temperature, electronic instrumentation for monitoring (remote and in real-time) of dissolved oxygen, temperature, and automation for control of the feed dispenser. It through the use of Arduino 1-R3 cards, together with XBEE shields for Arduino. Its work consist in the sensor parameters measurement, signal processing, and the sending and receiving data to and from the web-server.

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Anchored systems are widely used for slope stabilization in the construction of civil engineering projects in Colombia. These systems transmits a stabilizing force over a support surface (anchor head), inducing normal stresses on the face of the slope to generate an increase in the shear resistance of the soil involved in the failure surface. Regarding the design of the support surfaces it is common to find both, individual and continuous surfaces. The individual support surfaces correspond to isolated concrete blocks in which there is no structural union with adjacent anchor heads, these supports are commonly referred to as "dados" in Colombia; and the continuous support surfaces correspond to reinforced concrete slabs that guarantee the structural union between each of the existing anchor heads. Currently, there is no conceptual clarity as to the actual behavior of each of the support surfaces; therefore, it is not possible to fully evaluate compliance with the design hypotheses. With this in mind, a mathematical modeling was made using Finite Element techniques representing both cases. It was found that there are great differences in the contribution to the stability of the slope generated by each of the systems, which must be considered in the design process.

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In this study, activated biocarbon was prepared from coconut shell biocarbon by base activation using potassium hydroxide (KOH) as the dehydrating agent. The optimum preparation condition was determined by Response Surface Modelling (RSM) using Box Behnken Design (BBD). The relationship of independent factors i.e. activation temperature (T), holding time (t) and impregnation ratio (IR) was investigated towards maximum yield response, as measured through iodine value (mg/g). The optimum activation conditions were found to be temperature = 900 ºC, holding time = 15 min, and impregnation ratio = 1.75 which yielded higher iodine value (1169.19 mg/g). The correlation coefficient (R2=0.9223) obtained showed that the model is able to predict the iodine number value efficiently.

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The study is carried out in imperfect contact with a concrete slab wall attached to a panel based on rice straw compressed in a dynamic frequency regime. We will propose the characterization of thermal insulation for thermal resistance of contact (x=0.05m). The impact of heat exchange coefficients on the front face (x=0m) and the rear face (x=0.1m) on these resistors is shown.

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Universiti Teknikal Malaysia Melaka (UTeM) has to consider renewable energy as part of electricity generation to save cost of electricity. Photovoltaic (PV) system hereof is appropriate because it is reliable for sunny location like Melaka. Therefore, the purpose of this research is to carry out feasibility study of providing electricity from PV system for UTeM. The proposed system comprises of grid tied PV and battery storage. The techno-economic analysis of the proposed system was performed using Hybrid Optimization of Multiple Energy Resources (HOMER) software. The optimal size and the cost-effective configurations of the system were identified. From the simulation result, the optimal grid tied PV system has the minimum net present cost (NPC) and economic benefits over base system (utility grid) with 16.6% internal rate of return (IRR) and 5.7 years payback period. The results obtained can be used as references for the stakeholders and policy makers in developing grid tied PV system for university campuses.

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Abstract:

Proton exchange membranes were synthesized by using Polyvinyl Alcohol (PVA) and Styrene Acrylic Ester (SAE) copolymers, and modified with addition of nanoclays as loaded in order to improve the physicochemical and mechanical properties and to implement as electrolyte in a fuel cell and to produce energy. Proton exchange membranes were characterized by water uptake, ionic exchange capacity, oxidative stability and FTIR spectra. Maximum effort, deformation and Young´s Modulus were determinate by the tensile tests. It is observed that the membranes loaded with 2% had the highest values of water uptake 129%, due to the high hydrophobicity of PVA, this is reflected in the mechanicals properties since this membrane presented the lowest value of maximum effort, while for ion exchange capacity, loaded 3% membrane present the highest value 1,429 meq/g.

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Abstract:

The vast majority of variable exponent distributions retire in the context of reliability in one way. When talking about reliability, consider mainly the time lag between device interference and failure. In a bivariate or multivariate context, it is concerned with dependencies between failures, such as those of two components of the system. The univariate exponential distribution is also important in describing that age for a single component. Bivariate distributions with exponential marginal are also very widely used in describing the lifetime of the two components together. Bivariate exponential distributions often arise from shocks that cause cumulative damage to components that will eventually destroy components or cause cumulative damage. The shock numbers N1 and N2 required to multiply components 1 and 2, respectively, have a bivariate geometric distribution. This research concerns on Stress-Strength Reliability of a Two-Component System by using Gumbel’s Bivariate Exponential Distribution, type1. An application of the results is also provided in devices failure data.

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