Suchergebnisse

Carbon fiber reinforced polymers (CFRPs) have found diverse applications in the automotive, space engineering, sporting goods, medical and military sectors. CFRP parts require limited machining such as detouring, milling and drilling to produce the shapes used, or for assembly purposes. Problems encountered while machining CFRP include poor tool performance, dust emission, poor part edge quality and delamination. The use of oil-based metalworking fluid could help improve the machining performance for this composite, but the resulting humidity would deteriorate the structural integrity of the parts. In this work the performance of an oil-in-water emulsion, obtained using ultrasonic atomization but no surfactant, is examined during the milling of CFRP in terms of fiber orientation and milling feed rate. The performance of wet milling is compared with that of a dry milling process. The tool displacement-fiber orientation angles (TFOA) tested are 0°, 30°, 45°, 60°, and 90°. The output responses analyzed were cutting force, delamination, and tool wear. Using atomized vegetable oil helps in significantly reducing the cutting force, tool wear, and fiber delamination as compared to the dry milling condition. The machining performance was also strongly influenced by fiber orientation. The interactions between the fiber orientation, the machining parameters and the tested vegetable oil-based fluid could help in selecting appropriate cutting parameters and thus improve the machined part quality and productivity.

This paper investigates several aspects of the relationship between sovereign credit ratings and fiscal discipline. The analysis of over one thousand country–year observations for 93 countries during the 1999–2010 period reveals that a country's debt level is likely to increase with higher ratings, confirming the existence of pro–cyclicality and path dependence of ratings. In addition, the study finds no evidence to support the theory of Political Business Cycle, which implies that political ambitions may lead to fiscal worsening following a rating upgrade. The study findings further demonstrate that institutional quality is an important factor in the ratings–fiscal discipline nexus.

The paper shows that politically motivated interventions in the financial market in the form of bailing out borrowing firms reduce banks' incentives to gather valuable information about firms' projects. This loss of information is a hidden cost which adversely affects firm value. Firms invest resources and pay a premium to politically connected persons (BOD or other personnel). Such connections serve the twin purposes of hedging and enhancement of the value of collateral pledged against bank loans. Feeling secured, banks lose incentives to monitor borrowing firms. Thus, wealth effect of bailout from political connection is partially offset by the losses of valuable information brought about by bank lending. In equilibrium, the trade-off from gains out of political connections and costs due to losses from information-based bank monitoring depend on (i) the country's disclosure laws, (ii) the political environment, (iii) the premium paid to form connections, and (iv) the state of the economy.

In this paper we test the hypothesis that independent boards can insulate a company from the detrimental impact of corruption on its performance (proxied by innovation). To this purpose, we have estimated an innovation production function that links innovation outputs to innovation input (namely investment in R&D) on a sample of manufacturing subsidiaries controlled by British multinationals and located in 30 countries. Our analysis covers the period 2005¬‐2013. After controlling for the subsidiary's characteristics (including the ownership structure and whether the main shareholders are from Common Law countries), we find that independent boards may mitigate the negative impact of corruption on innovation as subsidiaries located in more corrupt countries and with more independent boards tend to invest more in R&D and register more valuable patents. These results still hold after controlling for the average age of the directors, the proportion of directors with no local business affiliations and government effectiveness.

In this paper we test the hypothesis that independent boards can insulate a company from the detrimental impact of corruption on its performance (proxied by innovation). To this purpose, we have estimated an innovation production function that links innovation outputs to innovation input (namely investment in R&D) on a sample of manufacturing subsidiaries controlled by British multinationals and located in 30 countries. Our analysis covers the period 2005- 2013. After controlling for the subsidiary's characteristics (including the ownership structure and whether the main shareholders are from Common Law countries), we find that independent boards may mitigate the negative impact of corruption on innovation as subsidiaries located in more corrupt countries and with more independent boards tend to invest more in R&D and register more valuable patents. These results still hold after controlling for the average age of the directors, the proportion of directors with no local business affiliations and government effectiveness.

Abstract
The antagonistic side effects of chemical medications led to the search for safe strategies such as biogenic agents. Correspondingly, this study aims to create biogenic, appropriate, auspicious and innovative therapeutic agents like Galaxaura elongata {GE}, Turbinaria ornata {TO} and Enteromorpha flexuosa {EF} macroalgae-based silver nanoparticles (Ag-NPs). The Ag+ reduction and the creation of Ag[GE]-NPs, Ag[TO]-NPs and Ag[EF]-NPs have been validated using UV–visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and zeta potential analysis, and the chemical composition of macroalgae crude extracts was estimated through gas chromatography–mass spectrometry (GC–MS). Further, macroalgae-based Ag-NPs were tested for their free radical scavenging activity DPPH, ABTS, anticancer activity in human liver carcinoma (HepG2) cell line, distinctive inflammation forms and elevated α-amylase. Results showed that the biosynthesized Ag-NPs have unique mechanical and physicochemical characters attributed to their high relative surface area, nanosized dimensions and spherical shape. At dose of 200 µg/mL, the DPPH radical scavenging capacity was maximized with Ag[TO]-NPs (67.26%); however, Ag[EF]-NPs was the most potent as ABTs scavenger (97.74%). Additionally, Ag[GE]-NPs had the maximum proteinase inhibitory action with 59.78%. The 1000 µg/mL of Ag[GE]-NPs, Ag[TO]-NPs and Ag[EF]-NPs revealed significant inhibitions of cell growth of HepG2 resulting in cell viabilities 5.92%, 4.44% and 11.33%, respectively. These findings suggest that macroalgae bio-capped Ag-NPs have magnificent biological potentials for safe biomedical applications.