Estimation of specific cutting energy in an S235 alloy for multi-directional ultrasonic vibration-assisted machining using the Finite Element Method

The objective of this work is to analyze the influence of the vibration-assisted turning process on the machinability of S235 carbon steel. During the experiments using this vibrational machining process, the vibrational amplitude and frequency of the cutting tool were adjusted to drive the tool tip in an elliptical or linear motion in the feed direction. Furthermore, a finite element analysis was deployed to investigate the mechanical response for different vibration-assisted cutting conditions. The results show how the specific cutting energy and the material’s machinability behave when using different operational cutting parameters, such as vibration frequency and tool tip motion in the x-axis, y-axis, and elliptical (x-y plane) motion. Then, the specific cutting energy and material’s machinability are compared with a conventional turning process, which helps to validate the finite element method (FEM) for the vibration-assisted process. As a result of the operating parameters used, the vibration-assisted machining process leads to a machinability improvement of up to 18% in S235 carbon steel. In particular, higher vibration frequencies were shown to increase the material’s machinability due to the specific cutting energy decrease. Therefore, the finite element method can be used to predict the vibration-assisted cutting and the specific cutting energy, based on predefined cutting parameters.Peer ReviewedPostprint (published version

Synthesis Of Polyol From Edible Oil Waste With Ozonolysis Technology

Polyol is a chemical compound that contains many hydroxyl groups. Polyol can be made from petroleum, nevertheless petroleum's price is increasingly high and petroleum itself is a non renewable resource,so it may be gone someday.Alternatively, synthesis of polyol can use other material that is renewable, in case it can use waste from edible oil. In experiment, polyol is made from edible oil waste(used palm cooking oil) through ozonolysis reaction. Beside ozone,as reactant are also used a mixture of methanol isopropanoal and water in certain ratio and sulphuric acid as catalyst.Mechanism of reaction will start at ozone attack and break the double bonds( C=C) of unsaturated fatty acid in the waste,and then hydroxyl groups of alcohol can made contact to produce polyol. The main purpose of experiment is to determine the optimum condition for making polyol with ozonolysis technology.The experiment will be carried out by vary temperature of ozonolysis reaction, mol ratio of oil-alcohol,reaction time and ozone concentration. The result of experiment show that hydroxyl number values of polyol vary from 92.75 to 265.62 and viscosity values vary from 9.228 to 20.403 cp. The optimum condition determined by response optimization program,and from experiment show that converting edible oil waste to polyol will be efficient with temperature 25'C, 3 hours reaction time, l:7 for oil and alcohol mol ratio and ozone concentration 6.3

Efficiency, scale economies and valuation effects : evidence from bank mergers in India

Original article can be found at : http://www.inderscience.com/ Copyright Inderscience PublishersThis paper examines two important issues related to bank mergers in India. First, we estimate potential economic gains of state owned banks if they undergo consolidation. Scale economies, returns to scale and profit efficiency of state owned banks during 1986 to 2003 are estimated based on stochastic frontier analysis. We find that many Indian banks exhibit potential cost savings from mergers provided they rationalize their branch networks although profit efficiency may not rise immediately. Second we measure the realized impact of bank mergers on shareholders’ wealth based on event study analysis. We find that in the case of forced mergers, shareholders of neither the bidder nor the target banks benefited. In the case of voluntary mergers, the bidder banks’ shareholders gained more than the target banks’ shareholders.Peer reviewe

An efficiency analysis of banking systems: a comparison of European and United States large commercial banks using different functional forms.

This paper aims at investigation the efficiency of European and U.S. commercial banks. Scale and scope economies indicators, as well as a measurement of X-efficiency are derived from three cost functions: Fourier flexible form, translog and Box-Cox. This allows checking the stability and the robustness of the evidence across the different specifications. Our results over the period 1995-98 show that overall the average cost curve is relatively flat with some evidence of scale efficiency gains. More puzzling are the results on the presence of scope economies.

New evidence on returns to scale and product mix among U.S. commercial banks

Numerous studies have found that banks exhaust scale economies at low levels of output, but most are based on the estimation of parametric cost functions which misrepresent bank cost. Here we avoid specification error by using nonparametric kernal regression techniques. We modify measures of scale and product mix economies introduced by Berger et al. (1987) to accommodate the nonparametric estimation approach, and estimate robust confidence intervals to assess the statistical significance of returns to scale. We find that banks experience increasing returns to scale up to approximately $500 million of assets, and essentially constant returns thereafter. We also find that minimum efficient scale has increased since 1985.Banks and banking ; Banks and banking - Costs ; Economies of scale

Fabrication and Analysis of TEOS- and MTES-based Aerogels Prepared via Rapid Supercritical Extraction

Silica aerogels were prepared using the precursor tetraethylorthosilicate (TEOS) and an organically modified TEOS derivative (methyltriethoxysilane, MTES) via a rapid supercritical extraction (RSCE) method. Multiple consistent batches of monolithic TEOS-based aerogels were fabricated via an eight-hour RSCE process. Fabricating TEOS-based aerogels with an RSCE method offers some distinct advantages. The main advantage is the relative simplicity of the RSCE approach: liquid precursors are mixed and poured into a mold in a hydraulic hot-press, where gelation, aging and extraction of liquid from the pores occur. The precursor recipe employs TEOS, ethanol, water, oxalic acid to catalyze hydrolysis, and ammonia to catalyze the subsequent polycondensation reactions. Earlier work on silica aerogels by our group focused on the use of tetramethylorthosilicate (TMOS)-based precursor mixtures. Reaction of TEOS to form sol gels yields ethanol as a byproduct. A process that releases ethanol, rather than methanol (as in the TMOS-based aerogels) may be more appealing for commercial applications, involving scale-up of the process. The TEOS-based aerogels have good optical transparency, bulk densities of 0.099(±0.003) g/cm3, surface areas of 460(±10) m2/g, and contain internal and external Si-O framework bonds as observed in FTIR spectra. Using SEM, the surface morphology of the aerogel samples was studied. MTES-based aerogels were also successfully fabricated using Union’s RSCE process, but with less consistent results than for the TEOS-based aerogels. About half the MTES aerogels remained monolithic. FTIR spectra indicate that the aerogels are organically modified; Si-CH3 groups are present in the aerogel framework. The MTES aerogels are hydrophobic

Resource-Based View and SMEs Performance Exporting through Foreign Intermediaries: The Mediating Effect of Management Controls

Following the resource-based view, this research empirically explores the role of formal and informal management control in mobilizing export resources to develop export capabilities, influencing the export performance of small and medium-sized enterprises (SMEs) in an interorganizational relationship context. Empirical data were collected using a survey administrated online to finance managers in Spanish SMEs which use foreign intermediaries to access export markets. In this setting, evidence mainly suggests, first, that management control systems (MCSs) play a relevant mediating role between the effect of, on the one hand, resources on capabilities, and, on the other hand, resources and capabilities on performance. Second, that MCSs and capabilities play a interrelated double mediating effect between the impact of resources on performance; more specifically, a significant double indirect effect is found (1) between financial resources, behavior control, customer relationship building capability and performance, and (2) between physical resources, behavior control, customer relationship building capability and performanc