Wednesday, 2 August 2017

Engineering Journal: June Issue 2017

Numerical Calculation and Analysis of the Normal Relationship of the Dual-Frequency Altimeter Backscatter Coefficient

AbstractTo improve effectively sea surface wind speed retrieval accuracy when it is raining, it is very interesting to find out a more accurate normal relationship between Ku band backscatter coefficient s0ku and C band backscatter coefficient s0c for a dual frequency altimeter (13.58GHz/5.25GHz). In this paper an electromagnetic scattering model with a rough surface profiles is established. In terms of the established rough sea surface model s0ku and s0c are calculated by electromagnetic numerical methods of method of moment (MOM) and Kirchhoff approximatation (KA) when the rms of the rough surface is various. The simulation results are in a good agreement by these two different methods: MOM and KA. Those calculated results show that the relationship between s0ku and s0c obtained by calculating electromagnetic scattering from Gaussian random rough sea surface profiles exists positive differences from the normal relationships while those obtained by calculating electromagnetic scattering from Exponential rough sea surface profiles exist negative differences from thoses. It is obvious that the calculated relationship can be in a good agreement with an empirical normal relationship by adjusting compositions of those ocean spectrums. It is a good way to find out the normal relationship between s0ku and s0c by theoretical calculation and analysis, and also is an effective way to study the ocean spectrum and sea states.

Keywords Dual frequency altimeter, Normal relationship, Backscatter coefficient, MOM, KA.

Click here to Download Full Paper

_____________________________

Hydration kinetics of calcium sulphate hemihydrate modified by water-soluble polymers

Abstract Pastes based on gypsum (calcium sulphate hemihydrate) and two chosen water-soluble polymer admixtures, i.e. hydroxyethylmethyl cellulose (HEMC) and poly(vinyl acetate) (PVAC) were prepared. The impacts of the polymers on gypsum setting, as well as thermal and mechanical properties were studied. Heat effect and the rate of setting depending on water to gypsum ratio and the presence of admixtures were measured. The results have shown a strong effect of the polymer admixture (1%) on the prolongation of gypsum setting time. The presence of polymer molecules in water solution hinders the crystallization process of gypsum dihydrate. HEMC and PVAC have also a significant influence on gypsum mechanical properties especially at low water content. Kinetics of the setting process of gypsum hemihydrate is discussed.

Keywords admixture, gypsum, heat of hydration/crystallization, hydroxyethylmethyl cellulose, poly(vinyl acetate), setting.

Click here to Download Full Paper

____________________________

A new novel crosslinker with space structure for low-polymer-loading fracturing fluid

Abstract Boron-based crosslinkers are used commonly to increase viscosity and to improve fluid-loss control and proppant transportability of guar and its derivative fluids. Boron crosslinkers are usually preferred because of their ability to reheal after shearing and their favorable environmental properties. In order to reduce both the formation and the proppant-pack damage from polymer residues and to reduce over-all fluid cost, more-efficient crosslinkers capable of crosslinking fluids with reduced polymer loading is of great interest. Previous studies demonstrated that polymer solutions have critical overlap concentration (C*), below which no intermolecular crosslinking leading to increased viscosity can occur. However, recent studies demonstrated that increased crosslinker size or length can lead to the crosslinking of polymer solutions well lower than the C* and can reduce polymer loading without compromising the rheology of the fracturing fluid.

This paper shows the effect of new crosslinkers with space structure capable of interacting with multiple poly-saccharide strands to form crosslinking networks at lower polymer loadings than conventional guar fluids. The crosslinker is formed by the reaction of boric acid and a Polyamine with six-member ring to improve the spatial structure. The formation procedures of the new crosslinker by Boric and six-member Polyamine is very simple, and the synthetic condition is also very mild. The concentration of guar fluid with this new crosslinkers can be reduced by 30%. In addition, the crosslinker reacted with glucose to improve the control of the fluid-viscosity buildup can make the product fit into broader applications. The time of the fluid-viscosity buildup ranges from 15 to 180s. The pH value is very important to the heat resistance characteristics of the fracturing liquid system, the heat resistance characteristics increase with the increase NaOH loading. The polymer residual of the new fracturing system with new crosslinkers is much lower than that with conventional crosslinkers because of the low polymer loading. The cost of new crosslinkers is low because of the low price of raw material and the simple formation procedure and the mild synthetic condition, which is very important for extensive used in the oil field.

Keywords Cross linker Boric acid, Polyamine space structure.

Click here to Download Full Paper

____________________________

ECC-based User Authentication Scheme for Wireless Sensor Networks

Abstract In 2016, Akansha S. et al. proposed an upgraded user authentication protocol. According to the implemented cryptanalysis on their scheme, some vulnerabilities have been found in registration and authentication part. In registra-tion part, the gateway uses generated value as secrecy and sends it to sensor node, which doesn’t have infor-mation about received secret value and cannot verify its identity. In authentication part, user is unable to check legiti-macy of received session key generated by sensor node. Mainly, the protocol has been implemented using only one way hash function, XOR and concatenation operations, which is not adequate to provide authentication and confidentiality. In this paper, we suggest ECC-based user authentication scheme for WSNs, which eliminates the drawbacks of the previous scheme. The protocol decreases the high cost public-key operations of the sensor node and substitutes them with symmetric-key based operations.

KeywordsAuthentication, Cryptography, Key agreement, Network security, WSN.

Click here to Download Full Paper

_________________________

Utilization of bottle caps in concrete

Abstract Advances in technology enhance human comforts and in the same time damages the environment. Plastic used as cap for containers preserve liquids in the bottles very well, but the disposal of caps particularly bottle caps which harmful to environmental. Hence an attempt has been made in the present investigations to study the influence of addition of waste materials like soft drink bottle caps dosage of 0%, 5%, 10%, 15% & 20% of total weight of coarse aggregate as fibers. M25 grade of concrete was produced by replacing coarse aggregate by plastic bottle caps. In this investigation caps were cut into strips. Experimental investigation was carried out adding bottle caps in concrete and tests were carried out as per recommended procedures by relevant codes. Split tensile strength increases with increase of bottle caps. Split tensile and flexural strength of 5.0 % bottle cap fiber concrete increase up to 1.72% and 13.23 % more than plain concrete(without bottle cap plastic) respectively.

Keywords plastic bottle caps, compressive strength, course aggregate, split tensile strength , flexural test.

Click here to Download Full Paper

__________________________

Switching System, a Zero Power Standby Solution

Abstract— This paper describes a novel standby system. The actual power consumption in standby mode is zero Watts. In this standby system the appliance is completely disconnected from it mains supply during standby mode. In addition from saving on electricity costs, it also has the added benefit of preventing hazardous situations whilst in standby mode. This novel standby system will set a new goal for manufacturers of consumer products to achieve.

Keywords Energy efficiency, energy harvesting, green design, standby, zero power.

Click here to Download Full Paper

__________________________

Kinetic modeling of Immobilized Yeast Batch Fermentation

Abstract The main purpose of this study was to choose the best model that will be further refined and used for controlling batch fermentation process using immobilised yeast cell in order to increase its productivity. This study investigated the immobilized Saccharomyces Carlsbergensis growth kinetics, ethanol productivity and substrate consumption (glucose) using computer simulation for different kinetic models, Monod, Contois, Teisser and other models which present the substrate and product inhibition. Batch fermentations take place with different cell density comparing immobilized yeast fermentation performance with free yeast. For each batch were evaluated kinetic parameters and after mathematical models. We have used three linearization models for estimation of kinetic parameters. Conclusions about the influence of cell immobilization on the fermentation performance were drawn based on analysis of the obtained model parameters. It was found that in some fermentation Monod and Teisser models were the most appropriate. For substrate and product inhibition the most approximate models were exponential.

Keywords Immobilization, inhibition, kinetic parameters, linearization, modeling.

Click here to Download Full Paper

_____________________________

Water Chemistry Management toward Corrosion for Secondary Cooling Piping of Multi Purpose Reactor GA Siwabessy Indonesia

Abstract The experimental of inhibitor, oxy and non oxy biocide effectiveness on suppressing the carbon steel by using the secondary water cooling system of RSG GAS was done. The observed parameter are corrosion rate, dissolved oxygen concentration , pH and conductivity. The variation concentration of inhibitor, oxy and non oxy biocide was applied. The corrosion rate and dissolved oxygen are measured by using Gamry electrochemical instrument, pH-meter and oxygenmeter, respectively. Whole experiment was carried out at room temperature. Speciment test is carbon steel with diameter of 16 mm and thickness of 8 mm, with the exposed are of 1cm2, polished by grid 220 up to 2000. The variation concentration was applied for all chemicals up to 60 ppm. From the experiment it is known that the rate corrosion is suppressed by the addition of inhibitor, higher concentration inhibitor will suppress much more. This phenomenon is strongly understandable by the experimental data that shows dissolved oxygen decreasement due to the presence of inhibitor. The higher concentration of inhibitor cause the lower dissolved oxygen concentration. No pH change observed which is means that the inhibitor does not give any contribution on releasing H+ or OH- that causing pH changing. The addition of oxy biocide suppress corrosion rate from 0.7±0.02 mils/yr to 0.5± 0.02 mils/yr. However, non oxy biocide addition does not give any significant effect.

Keywords rate corrosion, inhibitor, oxy biocide, non oxy biocide.

Click here to Download Full Paper

_____________________________

Haze Removal Using Color Attenuation Prior With Varying Scattering Coefficients

Abstract This paper deals with removal of haze using color attenuation prior. It will helps for dehazing single image. For dehazing linear model is used. It is based on atmospheric scattering model. In this technique saturation and brightness values of an image is considered. It is less time consuming algorithm and also it has greater dehazing effects. Also varying scattering coefficient is used for dehazing purpose. With the depth map of the hazy image, we can smoothly surmise the transmission and give back the scene radiance via the atmospheric scattering model, and thus effectively remove the haze from a single image. It can implement very easily.

Keywords Color attenuation prior, Scattering model, Linear model, Varying Scattering Matrix.

Click here to Download Full Paper

______________________________

Additive Manufacturing of PE/Fluorouracil Waffles for Implantable Drug Delivery in Bone Cancer Treatment

Abstract In this study, implantable polyethylene/fluorouracil waffles were additively manufactured by selective laser sintering using different laser energy densities. SEM-EDS revealed a porous morphology for both PE and PE/FU waffles. High dispersion of fluorouracil particles were observed in samples prepared under different conditions. The PE/FU waffles manufactured at 5W had the highest flexural modulus, probably due to better PE particle coalescence, higher sinter degree and the dispersion of FU particles in the co-continuous porous PE matrix. The PE/FU waffles showed an initial burst as well as a rapid drug released, which are desirable characteristics for cancer treatment. This profile provides a high initial concentration of the drug in the cancer cells and a subsequent controlled release sustaining levels of the chemotherapeutic agent in the region of the bone tumor.

Keywords Polyethylene/fluorouracil, Implantable drug delivery, Cancer treatment, Selective laser sintering.

Click here to Download Full Paper

No comments:

Post a Comment

Engineering Journal: September Issue 2017

About Modeling and Simulation of Heat Exchange Convective Surfaces of the Steam Generator Abstract — Among the priority issues that the mo...