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Abstract

Most studies on the PAFSIN pipes were oriented monitoring their behavior in laboratory conditions, focusing on the fluid and less influence on the environment laying on the mechanical properties in the short term then extrapolated mathematical term. Moreover, a large part of these studies refer only to the effect on PAFSIN composite samples without taking into account the specificities induced specific geometry pipeline. In this way, the effect PAFSIN pipes can be overlooked, which in practice can lead to significant errors of design and / or execution. Compared to existing studies, taking into account only the effect of a sealant (generally standardized solutions of acid or base) of the PAFSIN pipes, in the article to present the results of tests conducted on PAFSIN pipes buried in different types of land and attempted to surprise the complexity of the interactions of soil solution to the conduit.

Abstract

Several Job scheduling algorithms have been developed for Hadoop-Map Reduce model, which vary widely in design and behavior for handling different issues such as locality of data, user share fairness, and resource awareness. This article focuses on empirically evaluating the performance of three schedulers: First In First Out (FIFO), Fair scheduler, and Capacity scheduler. To carry out the experimental evaluation, we implement our own Hadoop cluster testbed, consisting of four machines, in which one of the machines works as the master node and all four machines work as slave nodes. The experiments include variation in data sizes, use of two different data processing applications, and variation in the number of nodes used in processing. The article analyzes the performance of the job scheduling algorithms based on various relevant performance measures. The results of the experiments are evident of the performance being affected by the job scheduling parameters, the type of applications, the number of nodes in the cluster, and size of the input data.

Experimental evaluation of damage influence on buckling performance of stiffened CFRP shells

Delamination type failures are often observed in carbon-epoxy composites, where catastrophic failure is generally preceded by constituent level damage accumulation. Out-of-plane loading such as internal pressure in a composite fuselage or out-of-plane deformations in compression-loaded post-buckled panel may lead to debonding of the frame or stiffener from the panel. On other hand, numerous investigations show the ability of stiffened composite structures to work in the post-buckling region, which is considered unsafe in the conventional design procedures. Experimental evaluation of damage influence on post-buckling performance of stiffened shells is essential for development of safe design guidelines that would allow exploitation of these structures in the post-buckling region. The results of this investigation show that a damaged stiffened composite shell can be loaded up to 200% of skin buckling load without any propagation of delaminations. This can serve as the base for more extended studies on the subject, including numerical modelling and improvement of the existing design guidelines.

Abstract

Design of a Pump-Jet Propulsor (PJP) was undertaken for an underwater body with axi-symmetric configuration using axial flow compressor design techniques supported by CFD analysis for performance prediction. Experimental evaluation of the PJP was carried out through experiments in Wind Tunnel Facility (WTF) using momentum defect principle for propulsive performance prior to proceeding with extensive experimental evaluation in towing tank and cavitation tunnel. Experiments were particularly conducted with respect to Self Propulsion Point (SPP), residual torque and thrust characteristics over a range of vehicle advance ratio in order to ascertain whether sufficient thrust is developed at the design condition with least possible imbalance torque left out due to residual swirl in the slip stream. Pumpjet and body models were developed for the propulsion tests using Aluminium alloy forged material. Tests were conducted from 0 m/s to 30 m/s at four rotational speeds of the PJP. SPP was determined confirming the thrust development capability of PJP. Estimation of residual torque was carried out at SPP corresponding to speeds of 15, 20 and 25 m/s to examine the effectiveness of the stator. Estimation of thrust and residual torque was also carried out at wind speeds 0 and 6 m/s for PJP RPMs corresponding to self propulsion tests to study the propulsion characteristics during the launch of the vehicle in water where advance ratios are close to Zero. These results are essential to assess the thrust performance at very low advance ratios to accelerate the body and to control the body during initial stages. This technique has turned out to be very useful and economical method for quick assessment of overall performance of the propulsor and generation of exhaustive fluid dynamic data to validate CFD techniques employed

.: (2014a), “Experimental evaluation of mechanical properties of friction welded dissimilar steels”, Cogent Engineering , Vol. 1 , 2014, pp. 1-10. [9] HANDA, A., CHAWLA, V.: (2014b), “An investigation on the effect of axial pressures on the mechanical properties of friction welded dissimilar steels”, Advances in Mechanical Engineering , Vol. 2014 , 2014, pp. 1-6. [10] HANDA, A., CHAWLA, V.: (2014c), “Investigation of mechanical properties of friction welded AISI 304 with AISI 1021dissimilar steels”, International Journal of Advanced Manufacturing Technology , Vol

Abstract

The concept of digital manufacturing supposes application of digital technologies in the whole product life cycle. Direct digital manufacturing includes such information technology processes, where products are directly manufactured from 3D CAD model. In digital manufacturing, engineering drawing is replaced by CAD product model. In the contemporary practice, lots of engineering paper-based drawings are still archived. They could be digitalized by scanner and stored to one of the raster graphics format and after that vectorized for interactive editing in the specific software system for technical drawing or for archiving in some of the standard vector graphics file format. The vector format is suitable for 3D model generating, too.The article deals with using of selected integral transformations (Fourier, Hough) in the phase of digitalized raster engineering drawings vectorization.

Abstract

In the past, research on the use of FRP in civil engineering has been focused on strengthening existing structures where FRP reinforcements were applied to the surface of concrete elements. Recently, the application of FRP reinforcements has been studied to replace steel reinforcements for use in areas of increased environmental loads, with a need to exclude the corrosion of the reinforcement or to ensure the electromagnetic neutrality of the individual elements of the load-bearing structure. The GFRP reinforcement ratio was verified considering failure modes in flexure and the bond of the GFRP reinforcement with concrete. Besides classical reinforcements, GFRP has also been used in prestressed variants, and the possibility of its use as permanent formwork has been verified. In terms of extending the use of non-metallic reinforcements, it is important to note the long-term exposure and possible degradation of the mechanical properties.

Abstract

Today’s automotive designers and material specialists regard lighter vehicles for less fuel consumption (economy and ecology) and higher safety to passengers. Metal matrix composites have been a large area of interest. Aluminium composite is potentially applied in automotive and aerospace industries, because it has a superior strength to weight ratio and is a light weight metal with high temperature resistance. Composites containing hard oxides and ceramics (such as alumina) are preferred for high wear resistance along with increased hardness. In this work, alumina and zinc are reinforced in Al-LM25 alloy through stir casting process, where alumina is varied 6% and 12% in Al-5%Zn. Various mechanical analyses were conducted and the effect of wear with different percentage of alumina reinforcement was studied. The resulting properties are imported in a piston, modelled using solid works, and analysed in ANSYS work bench. Imparting this new material for pistons could introduce deep design and improvements in engine operation of a vehicle.

Abstract

The article describes a way of evaluating the power line channel frequency response and input impedance by means of the linear time-invariant (LTI) power line generator. Two possible methods are introduced for the calculation of primary parameters: the first method depends on the physical realization and physical dimension of the cable, and the second method is derived from the data provided by typical electrical cable manufacturers. Based on these methods, a comparison of transfer functions was made. This is followed by measurement evaluation and numerical verification on a simple topology

Abstract

This paper presents an attractive and a new voltage-mode quadrature oscillator using a single Fully Balanced-Voltage Differencing Buffer Amplifier (FB-VDBA) as the active element. The circuit structure is very simple, consisting of merely one FB-VDBA, one resistor and two capacitors. The circuit is implemented using the commonly available OPA860 which results in low output impedance and high current drive capability. The proposed circuit also has a suitable architecture for IC production. Experimental results which are matched well with the theoretical assumptions are given.