Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

One of the major sources of petroleum products is obtained from the sea (offshore and onshore). Here the major problem faced by the worker is,maintaining the constant pressure and flow till the extreme ends. In this paper, the parameters such as pressure and flow are maintained constantlyby implementing control valves depending on the different pressure and flow rate of the transmitting pipe. PLC (Programmable Logical Controller)is used to automatically regulate the flow and pressure during petroleum product transportation by controlling the percentage of opening of thecontrol valves and pumps respectively. The required set point for pressure and flow rate are obtained by implementing a suitable controller thatregulates in a long transmitting concrete pipes. For this, a PLC based PID controller is developed and its open loop responses are identified. Thesimulation studies are carried out in the MATLAB/SIMULINK platform to ensure the performance of the controller. The controller tuning isdone by ZN (Ziegler and Nicholas) PID and Simple-IMC (Internal Model Control) PID, Shams tuning IMC-PID controller. The simulation resultprovides better control action when Shams IMC-PID controller is used. Shams IMC-PID controller is experimentally verified on the lab scale-setupand the results prove that it provides most consistent performance as compared to ZN and Simple-IMC PID controllers.

The Weibull distribution is a useful statistical model that can be used to describe the multipath fading in nowadays wireless communicationenvironments. In this paper, the bit error rate (BER) performance of Low-Density Parity-Check (LDPC) coded communication systems usingdifferent decoding rules is presented over Weibull fading channels by means of comparative computer simulations. It is shown that, especiallyfor the case of the Belief Propagation (BP) decoding rule, significant performance improvement can be achieved in comparison with uncodedtransmission when the channel is assumed to have Weibull fading.

The funicular concept has often been used in different stages of structural analysis and design. This paper presents two new methods: Analytical,A-FDM, and Numerical method, N-FDM, based on a parametric application of the original Force Density Method (FDM). This is an especiallyuseful way of visualizing a set of solutions and optimizing, i.e. selecting one specific funicular related to a set of constraints. Two structuralalgorithms are implemented iteratively with Maple®in real time, and output is also linked to AutoCAD®. Maple®facilitates control of geometricalconstraints, while AutoCAD®helps to show all parameterized data. Because of their practical interest, special emphasis is placed on masonrystructures using a Limit Analysis approach and preliminary design. Examples of the application of both methods are depicted

In this paper, a rotary electromagnetic microgenerator is analyzed, designed and built. This microgenerator can convert human motions to electrical energy. The small size and use of a pendulum mechanism without gear are two main characteristics of the designed microgenerator. The generator can detect small vibrations and produce electrical energy. The performance of this microgenerator is evaluated by being installed peak-to-peak during normal walking. Also, the maximum harvested electrical energy during normal walking is around 416.6 μW. This power issufficient for many applications.

A small card used for detecting hydrogen gas in a crystal growth system by the liquid phase epitaxy technique was designed and built. Thesmall size of the card enables its portability to other laboratories where leakage detection of hydrogen or other flammable gas is required. Carddimensions are approximately 10 cm long and 5 cm wide enabling easy transportation. The design is based on a microcontroller which reads thesignal from the hydrogen sensor and internally compares the read value with preset values. Depending on the signal voltage a red, yellow or greenLED will light to indicate the levels of concentration of the flammable gas. The card is powered by a 9 V battery.

In this present investigation, 2-imino-(3,4-dimethoxybenzyl)ethane sulphonic acid was anchored on a silver nanoparticle mediated by sugarcanesap. The Schiff base was synthesized from 2-aminoethanesulphonic acid and 3,4 dimethoxybenzaldehyde under lemon juice catalyzed conditionswhile the nanoparticles were obtained by careful stirring of sugarcane sap and 1 mM AgNO3in the ratio of 1:10 respectively at room temperature.The resulting nanocomplex was formed by gentle heating and stirring of the silver nanoparticles solution and the ligand at a temperature of about80◦C for 3 h. The ligand, nanoparticles and nanocomplex were characterized using UV–vis spectrophotometer, scanning electron microscope,FT-IR and XRD machines. From the UV–vis results, surface plasmon bands (SPBs) were observed at 475 nm for the nanoparticle within 1 hof the reaction and 450 nm for the nanocomplex. The ligand exhibited absorption bands at 310 nm, 280 nm and 230 nm which are due to -electron transitions within the chromophores. The strikingly broad nature of the SPBs especially in the nanoparticles revealed that the particlesare kinetically favored, nucleate easily and are polydispersed and the blue shift observed in the nanocomplex suggested further reduction in theparticle size therefore giving us a clue on how to tailor the products by tuning the raw materials. From the scanning electron micrographs, themorphologies and growth mechanisms revealed oriented attachment for the nanoparticles onwards digestive ripening for the nanocomplex. All thesynthesized materials proved to be potential antibacterial agents as they showed great inhibition to the growth of some bacterial strains with theactivity enhanced in the nanocomplex.

Determination of tensile properties of metals or alloys is based on its type and shape which are found to be important aspects. Tensile specimen thickness, width, and rolling force direction affected the tensile properties of conventional metals such as copper sheet. Nevertheless, tensile specimen standards are still not specified yet, especially with regard to advanced materials such as thin wall ductile iron (TWDI). Following the recent findings of large deviations of tensile properties in TWDI plates, this paper describes a study of the effect of specimen width on the tensile properties of aluminium and steel sheets. The purpose of this study was to investigate whether the similar behaviour of tensile properties of TWDI would also occur in other metals. As-received commercial aluminium sheet grade and general structural hot-rolled steel were used for tensile specimen according to standard JIS Z2201 No. 13(b) and 5. The results showed that aluminium was more sensitive to tensile specimen width than compared steel.

In the world, researchers are working very intensively in the development of soil organic carbon (SOC) inventories. Soil organic carbon is veryimportant because it constitutes the largest reservoir of carbon in terrestrial ecosystems. Maintaining and increasing soil carbon is an option toreduce the amounts of CO2in the atmosphere, and thereby, to reduce or mitigate climate change. The SOC is now a topic of great interest hence itis recommended to know the amount of SOC along the profile to select and evaluate those areas that should be preserved. The aims of developingApp SOC plus were to eliminate the calculate errors of SOC and to make a tool to estimate SOC in field. The common units of measurement ofsoil properties were employed: bulk density in mg mL−1, horizon thickness in centimetres, stoniness and organic carbon in percentage. The AppSOC plus was developed in the Android platform. App SOC plus involves a three-step process: introduction of soil properties, calculation of SOCto horizon and soil profile, and conversion of units using the international and English systems. As a result, there will no longer be confusionswith conversion units using App SOC plus; with App SOC plus the soil organic carbon can now be calculated or/and estimated because it providesinstructions (aids) to estimate the soil properties necessary to calculate the SOC in the soil profile. You can save time in the calculation of SOC.App SOC plus is a tool for diagnosis in the field.

Cactus prickly pear (Tuna) harvest is a complicated operation that continues in a rudimentary way, in the majority of cases manual and with the help of tools such as knives and rods which sometimes affect the fruit. In this research is analyzing the possibility of building a tool that meets the characteristics sufficient for a good harvest, one of the factors to consider is access due to the restrictive features of the cactus prickly pear (height and distribution of the joints), forcing the use of tools to achieve it (with sometimes unfavorable results). This is how arises the need to create a device that adapts to the needs and solve the problem of harvest of tuna. Field studies which were fundamental to the design, such studies were obtained measurements and tests of strength, which were carried out with instruments properly designed for the type of fruit. Generated a picker mechanism of cactus prickly pear (tunas), which according to your design could achieve a high level of harvest compared to which today has, thanks to the configuration of the mechanism and the way they get their movements lead to a suitable environment for personnel performing this activity.

Monitoring of water sources is a major concern worldwide. Wireless sensor networks (WSN) may be used for this monitoring. However, current systems employ mainly physical sensors for variables such as temperature, pressure, humidity and light. Wireless chemical sensors networks (WCSNs) for environmental monitoring are scarce due to the lack of autonomy of conventional sensors. This paper presents results of a WCSN for monitoring pH based on ion selective field effect transistors (ISFETs). Sensing nodes employ a human interface required for in situ calibration of chemical sensors. Unlike most studies, our work evaluates the network employing chemical measurements and wireless network metrics. Results show zero packet losses by using a time division multiple access (TDMA) protocol. The network allows wireless communication within 300m including attenuation from buildings and trees. Therefore, the system presented in this paper is suitable for long range applications with unobstructed line of sight. pH measurements present a standard deviation below 1%, showing high repeatability. When compared to a commercial pH meter, difference in measurements is below 5%. As a  consequence, accuracy is adequate for the application. Measurements also  presented high stability during 3 h of continuous measurement.