Effects of Electrode and Workpiece Materials on the Sustainability of Micro-EDM Drilling Process

Gianluca D’Urso,Claudio Giardini,Chiara Ravasio 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.11

An analysis on the sustainability of micro-EDM drilling is presented. A process sustainability index was calculated taking into account energy consumption and tool wear during the drilling process. The machining accuracy was also taken into account to calculate the overall sustainability index. The index was validated considering the drilling of three different workpiece materials (stainless steel, tungsten carbide and aluminium) with two electrode materials (brass and tungsten carbide) and different process parameters. An analysis about the influence of workpiece and electrode materials on the sustainability index was carried out. In general, the tool wear has the highest impact on the process sustainability. Considering only the wear and the energy consumption, brass electrode is much more sustainable than the tungsten carbide one for all the tested conditions. This gap is less remarkable if the respect of dimensional tolerances and the consequent percentage of non-conformity is taken into account. From the point of view of the workpiece material, aluminium minimizes the process environmental impact. Finally, the effects on the index of the process parameters, the thermal and electrical characteristics of the electrode and the workpiece materials were evaluated. These results can be useful for approaching a more environmental-oriented strategy in manufacturing.

Investigation on power discharge in micro-EDM stainless steel drilling using different electrodes

G. D’Urso,G. Maccarini,M. Quarto,C. Ravasio 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

The present work deals with the execution of through micro-holes on stainless steel plates using a micro-EDM (Electrical dischargemachining) machine. The investigation focuses on the influence of different electrodes’ materials and power discharge on both the processperformance and the dimensional characteristics of the holes. The experimental campaign was carried out by varying peak currentand voltage in order to achieve both high and low power discharge conditions. Tubular electrodes made of three different materials (tungstencarbide, brass and copper) were used. The indexes taken into account were Material removal rate (MRR), Tool wear ratio (TWR),Diametral overcut (DOC) and Taper rate (TR). Brass and copper electrodes always resulted to be the best solution in terms of drillingspeed even though the wear of these electrode types is remarkable higher than the tungsten one. On the opposite, tungsten carbide electrodesresulted to be the best solution when high dimensional and geometrical precision is required. Concerning the finishing of the holeinner surface, the best results were achieved using tungsten carbide electrode.

언어학과 문학은 공조할 수 있는가(해야 하는가)? : Can (Should) They Work Together?

D'Urso, Vincenza 국어국문학회 2004 국어국문학 Vol.- No.137

This paper has been contributed to the 47th Conference of the Society of Korean Language and Literature, held in June 5-6 at Ehwa Womens University, in Seoul. I had been asked to give a contribution on the status of literary and linguistic education in Italy and on the significance of an interdisciplinary approach to literary criticism based on a cooperation between literature and linguistics or other disciplines. Aim of the contribution is not to shed new light on the interdisciplinary research trends, by presenting the new most popular theories of literary criticism, but rather to try and describe the Italian current research directions on the Italian peninsula regarding Italian Studies, or Studies on the National Language and Literature. Approaches are manyfold and varied, as research centers at universities are numerous, and this paper will therefore necessarily be a limited account of the current Italian situation. However, it can be surely stated that the majority of approaches seem to consider fundamental a cooperation between Linguistics and Literature. I will be mentioning only methodologies of literary criticism related to linguistics, leaving out others such as Marxist determinism and gender or class-oriented critical approaches, which seem more based on historical and sociological aspects, certainly important but not determinant for the conference topic. The paper is greatly based on the guidelines set by one of the major figures in the History of Italian Literature and in the History of Literary Criticism, Prof. Franco Suitner, who has taught at the University of Leiden, at the University of Venice (Ca Foscari) and currently teaches at the University of Rome (Roma Tre). The first part deals with the definition of the idea of literary masterpiece and of linguistic analysis. Being a literary masterpiece by definition a work of art made of words, a product of language, any analytical approach must necessarily pass through the filter of a linguistic analysis. The linguistic approach to the analysis of literary texts has been strongly applied in the West, especially starting from the XIX century. The discrepancy between the norm and original works by individual authors has been differently defined by theorists of literary analysis. It is, however, a concept which can be found in all formalist approaches of the XX century, in particular in the Russian Formalism, and in esthetic theories linked to Structuralism and to Semiology. All such theories consider artistic language as something special compared to the norm of everyday language. As Suitner affirms,(…) One positive effect of Formalism has been to bring to perfection the techniques for the description of textual forms (…). On the opposite, the most negative effect can be found in the birth of too technical terminologies, used for the sake of themselves, which have detached literature from its natural public, the readers. This happened based on the belief that the comprehension of literary masterpieces should be exclusively limited to scientists. The second part deals more directly with the relation between literary criticism and philology, a discipline which has a strong tradition in Italy. In its strict sense, philology aims at recuperating the original version of literary works, or the version closest to the original. Several methods of analysis have been elaborated over the centuries, starting with Humanists in the Ⅶ and Ⅷcenturies. But it is enough to remember that philology remains for Suitner essentially a preliminary technical operation, substantially separated from the proper literary critique, which intervenes when technicians [philologists] have already completed their precious work and have already prepared a text ready for critical readings. This interpretation recognizes the fundamental role philology plays in literary criticism, even though this statement does nor imply that a critic must also be a good philologist. Whereas it is important for a critic (or for the reader) to have a good text to analyse (or read), it is indeed irrelevant whether the good text has been prepared by the critic or by someone else. In this specific area of research Italy has contributed more than any other country and the critic and philologist Gianfranco Contini (1912-1990) can be considered one of the most prominent figures among the researchers of philology of textual variants or, as it is also called in France, genetic criticism. The third part briefly touches the problems related to literary criticism in the age of computers, by evaluating the advantages and dangers of IT intervention into the literary field. In spite of the undeniable advantages of having more data than ever at our disposal, the importance of individual analysis and elaboration is still indispensable for the production of a good critical work. This is obviously not true in a purely linguistic analysis, where the application of technical devices seems to be more productive and fruitful than in literary criticism. As a conclusion, some recommendations are made, quoting Suitner, for the formation of good literary critics: passion, discipline, amplitude of the personal knowledge are for Suitner fundamental qualities, whereas extreme specialization should be avoided, because the literary critic should not apply one single method of interpretation, but rather apply them all, so that his/her object of study can be seen under a more complete light.

언어학과 문학은 공조할 수 있는가(해야 하는가)?

Vincenza D'Urso 국어국문학회 2004 국어국문학 Vol.- No.137

Poetry as a way to teach Korean language

V. D"Urso 서울대학교 국어교육연구소 2004 국어교육연구 Vol.14 No.-

Comparison of Rabbit Caecal Content and Rabbit Hard Faeces as Source of Inoculum for the In vitro Gas Production Technique

Bovera, Fulvia,D'Urso, Simona,Di Meo, Carmelo,Piccolo, Giovanni,Calabro, Serena,Nizza, Antonino Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.11

In order to find an alternative source of inoculum to caecal content for studying the fermentation activity of rabbit hindgut, caecal content and faeces of 25 hybrid Hyla rabbits were used as inocula for an in vitro gas production trial. About 1 g of three substrates (dehydrated alfalfa meal, dehydrated beet pulp, barley) was weighed, in quadruplicate per inoculum, in 120 ml bottles; 75 ml of anaerobic medium and 4 ml of reducing solution were added and bottles were placed at $39^{\circ}C$. Caecal content and faeces were diluted respectively 1:2 (CI) and 1:8 (FI) with anaerobic medium and were introduced in the respective bottles (10 ml). Gas production was recorded 20 times at 2-24 h intervals throughout fermentation (96 h). The fermentation characteristics (i.e. degraded organic matter, OMd; potential gas production, A; fermentation rate, Rmax; time at which it is reached, Tmax; pH, volatile fatty acid, VFA) were studied by inoculum and feedstuffs. The feedstuffs, according to their chemical composition, showed very different fermentation characteristics. In particular, OMd, A and Rmax allowed feedstuff classification as follows: barley>beet pulp>alfalfa. The inocula differ (p<0.05) in Tmax, were higher for CI (15.53 vs. 11.96 h) and in VFA production. In particular, CI produced higher levels of acetate (38.9 vs. 33.4 mM/g OM incubated, p<0.01) and isobutyrate (0.72 vs. 0.42, p<0.01) but less propionate (7.1 vs. 10.3, p<0.01) and butyrate (11.3 vs. 14.0, p<0.01). However, the trend of gas production, similar for the inocula according to the fermented substrate, and the good regression equation to estimate some caecal fermentation parameters from faeces suggest that, after standardisation, the faeces could be used as an alternative inoculum for gas tests in rabbit.

Aluminum 6060-T6 friction stir welded butt joints: fatigue resistance with different tools and feed rates

S. Baragetti,G. D’Urso 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.3

The fatigue behavior of AA6060-T6 friction stir welded butt joints was investigated. The joints were produced by using both a standardand a threaded tri-flute cylindrical-tool with flat shoulder. The friction stir welding process was carried out using different feed rates. Preliminary tensile tests, micrograph analyses and hardness profile measurements across the welds were carried out. Welded and unweldedfatigue samples were tested under axial loading (R = 0.1) with upper limits of 104 and 105 cycles, using threaded and unthreaded(standard) tools at different feed rates. The best tensile and fatigue performance was obtained using the standard tool at low feed rate.

Diets with Different Forage/Concentrate Ratios for the Mediterranean Italian Buffalo: In vivo and In vitro Digestibility

Fabio, Zicarelli,Calabro, Serena,Piccolo, Vincenzo,D'Urso, Simona,Tudisco, Raffaella,Bovera, Fulvia,Cutrignelli, Monica I.,Infascelli, Federico Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.1

In vivo and in vitro digestibility of 6 diets with a forage to concentrate ratio (F/C) ranging from 100 to 50:50 (diet 1: all hay, diet 2: 90:10, diet 3: 80:20, diet 4: 70:30, diet 5: 60:40, diet 6: 50:50) were investigated using 6 buffaloes in a $6{\times}6$ Latin square design. For the in vivo trial, the individual faeces of buffaloes were collected 3 times per day for 7 days. Individual pooled faeces and samples of each diet were analysed for chemical composition and insoluble acid ash (AIA) contents in order to estimate the coefficient of apparent digestibility (ADC). On the last day of the in vivo trial a sample of faeces was collected from each animal and used as inoculum for the in vitro test, using the gas production technique (IVGPT). The in vivo organic matter digestibility (ADC) rose as the percentage of concentrate increased up to the 70:30 (F/C) diet (67.01, 73.03, 78.06 and 79.05, respectively for diets 1, 2, 3 and 4); the other two diets (60:40 and 50:50 F/C) unexpectedly did not follow this trend (75.11 and 79.06, respectively for diet 5 and 6). However, these data agree with the results of the in vitro trial. The ADC was positively correlated with the dOM (p<0.001), but not with the gas production at different times; cumulative gas production recorded at the end of incubation (OMCV) showed an irregular trend and was not closely correlated to degraded OM. Estimation of in vivo digestibility from in vitro fermentation data was acceptable, despite leaving room for improvement.