El costo estándar en condiciones de máxima eficiencia : una meta a alcanzar

El costo estándar se calcula anticipadamente considerando la máxima eficiencia operativa. Como consecuencia, configura una meta a alcanzar. Toda la imaginación y el esfuerzo deben encausarse para lograr un costo de producción real muy cercano al estándar. Mientras menos diferencia se verifica entre el costo estándar y el real, más cerca se está del nivel óptimo de eficiencia. Ello estimula y entusiasma a los responsables de las diferentes áreas para alcanzar la meta fijada. El modelo que se presenta, no prevé consumos reales físicos inferiores a los estándares. Pero, es más flexible respecto a las magnitudes monetarias. Admite volúmenes de producción fluctuantes a lo largo del ejercicio económico y muestra un tratamiento novedoso de los costos indirectos de fabricación.Fil: Pellegrino, Antonio. Universidad Nacional de Cuyo. Facultad de Ciencias EconómicasFil: Costa, Marina. Universidad Nacional de Cuyo. Facultad de Ciencias Económica

Stress Concentration and Material Failure During Coiling of Ultra-Thin TRAC Booms

Ultra-thin TRAC booms are a promising technology for large deployable structures for space applications. A manufacturing process producing composites TRAC booms with flange thickness as low as 53 μm is proposed. Coiling behavior around hub with radii ranging from 19.1 mm to 31.8 mm is studied both experimentally and through finite element simulations. Due to the thinness of the TRAC boom, a buckle appears in the inner flange, in the transition region from the fully deployed to the coiled configurations. Material failure is observed at this location, and this correlates well with stresses computed in simulation, coupled with the fiber microbuckling failure criterion. Reducing the thickness, either by changing the laminate or by improving the manufacturing process, is shown to reduce stresses, allowing coiling around smaller hubs without material failure

Stress Concentration and Material Failure During Coiling of Ultra-Thin TRAC Booms

Ultra-thin TRAC booms are a promising technology for large deployable structures for space applications. A manufacturing process producing composites TRAC booms with flange thickness as low as 53 μm is proposed. Coiling behavior around hub with radii ranging from 19.1 mm to 31.8 mm is studied both experimentally and through finite element simulations. Due to the thinness of the TRAC boom, a buckle appears in the inner flange, in the transition region from the fully deployed to the coiled configurations. Material failure is observed at this location, and this correlates well with stresses computed in simulation, coupled with the fiber microbuckling failure criterion. Reducing the thickness, either by changing the laminate or by improving the manufacturing process, is shown to reduce stresses, allowing coiling around smaller hubs without material failure

A data-driven rate and temperature dependent constitutive model of the compression response of a syntactic foam

Polymeric syntactic foams are used in aerospace and marine applications requiring low density and low moisture absorption together with high specific strength and stiffness. Their mechanical response is highly sensitive to temperature and strain rate and such sensitivity must be modelled accurately. In this study, the uniaxial compressive response of a polymeric syntactic foam is measured at strain rates in the range [10−3, 2.5·103] /s and temperatures varying between −25°C and 100°C. The resulting dataset is used to train a neural network to predict the compressive response of the foam at arbitrary strain rates and temperatures. It is found that the surrogate model is highly effective in predicting the material response at temperature and rates not included in its training set. Finally, a stochastic version of the data-driven model to allow predictions of the variability in the stress versus strain response is proposed

Annoted provisional list of the Crambidae (Lepidoptera, Pyraloidea) of the Salento Peninsula (South Italy), second contribution

ItLa fauna entomologica della Penisola Salentina (Sud Italia) risulta essere scarsamente indagata, come affermato in Durante e Panzera (2004) e ribadito in diversi lavori (es., Durante e Potenza, 2016; Durante et al., 2021). I risultati di questo lavoro evidenziano, nell'area geografica investigata, la presenza di 18 specie della famiglia Crambidae (superfamiglia Pyraloidea), di cui 4 relative alla sottofamiglia Odontiinae, 7 relative alla sottofamiglia Crambinae, 1 relativa alla sottofamiglia Evergestinae, 1 relativa alla sottofamiglia Pyraustinae, 2 relative alla sottofamiglia Spilomelinae, 1 relativa alla sottofamiglia Glaphyriinae, 2 relative alla sottofamiglia Acentropinae. Inoltre, sulla base della bibliografia consultata, delle 18 specie di Crambidae rinvenute, 15 sono nuove segnalazioni per il Salento, di cui 6 risultano nuove per l'Italia meridionale, 6 per la Puglia e, di conseguenza, solo 3 erano già state segnalate nel territorio salentino. I dati esposti in questo lavoro non possono ancora considerarsi definitivi, in quanto si stanno esaminando ancora molti esemplari, ciò nondimeno si è ritenuto di un certo rilievo pubblicarne i risultati.EnAs pointed out in Durante and Panzera (2004) and various other works (e.g. Durante and Potenza, 2016; Durante et al., 2021), the entomological fauna of the Salento Peninsula (Southern Italy) has not been extensively investigated. The results of this study highlight, in the studied area, the presence of 18 species in the family Crambidae (superfamily Pyraloidea), of which 4 belong to the subfamily Odontiinae, 7 to the subfamily Crambinae, 1 to the subfamily Evergestinae, 1 to the subfamily Pyraustinae, 2 to the subfamily Spilomelinae, 1 to the subfamily Glaphyriinae, 2 to the subfamily Acentropinae. In addition, based on the consulted bibliography, of the 18 species of Crambidae discovered, 15 are new records for Salento, of which 6 are new for Southern Italy, 6 for Apulia and, accordingly, only 3 having already been reported for the Salento. The data presented in this paper are not to be considered definitive, as the authors are still examining the material. Nonetheless, the results achieved thus far are thought to be of some value

Documentary heritage: fungal deterioration in Compact Discs

AbstractIn recent years, there has been an exponential growth in the use of digital media for data storage and the creation of museums, libraries and digital archives. In particular, Compact Discs Recordable (CD-R) have become one of the most used tools for archiving documents related to cultural heritage. Many authors have investigated only the CD longevity, but very few studies have focused on their biological deterioration. The aim of this work was to examine the CD-R biodeterioration following two ways: (1) search badly preserved CD-R, showing clear degradation spots and verify that it is fungal deterioration; (2) fungal inoculation tests on blank CD-R to verify their bioreceptivity. The analysis of a badly preserved CD-R showed clear degradation spots, highlighting, after cultural and molecular analysis, the presence on the surface of three different fungi: Chaetomium globosum, Trichoderma atroviride e Coniochaeta sp. For the in vitro inoculation tests we used conidia suspensions of Cladosporium cladosporioides and Penicillium chrysogenum, and we observed the growth for 6 months. At the end of experiment, both fungi colonized the CD-R surface with hyphae and mycelia clearly visible, causing also loss of material and fractal structure presence. For the CD-R use as cultural heritage archiving, the correct storage is an essential phase and, in light of the results obtained, it will be necessary not only to consider the environmental factors (temperature, relative humidity) but also the biological deterioration caused by airborne fungi. Therefore, effort needs to be taken to regularly monitor temperature and relative humidity and it is essential to periodically conduct cleaning of optical media

Dynamic response of Advanced Placed Ply composites

This work investigates the high strain rate behavior of AP-PLY composites. The large representative volume elements and brittle nature of this material necessitated the use of a bespoke Split-Hopkinson bar apparatus. AP-PLY and baseline laminates were subjected to tensile loading at strain rates of 30 s-1. Results were compared with quasi-static data to evaluate whether the laminate architecture introduced any strain rate dependency. In addition, the dynamic experiments were simulated using a multiscale modeling framework, providing further insights into the micromechanisms governing material behavior. The moduli of the AP-PLY composites were found to be strain rate independent, however, strengths were found to be marginally higher than those of their baseline counterparts. At high strain rates, the strain concentrations induced by the geometry of the individual tapes at through thickness undulations and tow boundaries were less significant due to reduced out-of-plane tow straightening and delamination. As a result, no reduction in AP-PLY strength in comparison to the baseline laminates was obtained. These differences in deformation micromechanisms led to an improvement of the damage tolerance when subjected to dynamic loading

Heterochromatin distribution in selected taxa of the 42-chromosomes Orchis s. l. (Orchidaceae)

In six 42-chromosomes taxa belonging to genus Orchis s. l. heterochromatin location and distribution and staining properties were analysed by means of C-banding and of the fluorochromes 4'-6-diamino-2-phenylindole-2HCl (DAPI) and Hoechst 33258. Most species could be distinguished on the basis of heterochromatin amounts and distribution. In the species O. mascula and O. provincialis most DAPI-positive sites did not co-localize with C-bands. DAPI revealed bright fluorescence at telomeric or subtelomeric regions of numerous chromosomes of O. mascula and particularly large/bright blocks at the telomeres of O. provincialis. In O. x penzigiana (Orchis mascula ssp. ichnusae x O. provincialis) overall heterochromatin distribution followed that of the parental species. In Neotinea group all DAPI positive bands co-localize with C-bands, but have different distribution in the taxa analysed. Present and literature data indicate a high level of plasticity of heterochromatin organization in Orchis s. l., and suggest evolutionary pathways in agreement with recent molecular data