Internal stresses and breakup of rigid isostatic aggregates in homogeneous and isotropic turbulence

By characterising the hydrodynamic stresses generated by statistically homogeneous and isotropic turbulence in rigid aggregates, we estimate theoretically the rate of turbulent breakup of colloidal aggregates and the size distribution of the formed fragments. The adopted method combines Direct Numerical Simulation of the turbulent field with a Discrete Element Method based on Stokesian dynamics. In this way, not only the mechanics of the aggregate is modelled in detail, but the internal stresses are evaluated while the aggregate is moving in the turbulent flow. We examine doublets and cluster-cluster isostatic aggregates, where the failure of a single contact leads to the rupture of the aggregate and breakup occurs when the tensile force at a contact exceeds the cohesive strength of the bond. Due to the different role of the internal stresses, the functional relationship between breakup frequency and turbulence dissipation rate is very different in the two cases. In the limit of very small and very large values, the frequency of breakup scales exponentially with the turbulence dissipation rate for doublets, while it follows a power law for cluster-cluster aggregates. For the case of large isostatic aggregates it is confirmed that the proper scaling length for maximum stress and breakup is the radius of gyration. The cumulative fragment distribution function is nearly independent of the mean turbulence dissipation rate and can be approximated by the sum of a small erosive component and a term that is quadratic with respect to fragment size.Comment: 31 pages, 19 figure

THE FIRST RECORD OF THE BIRCH MOUSE SICISTA IN THE UPPER PLEISTOCENE SEDIMENTS OF CAVERNA GENEROSA (COMO, NW ITALY), WITH MORPHOMETRICAL, MORPHOLOGICAL AND ECOLOGICAL CONSIDERATIONS

In this study the only one specimen collected and attributed to Sicista cf. subtilis from the Caverna Generosa has been described: a right mandible with first molar and m/2-m/3 alveoli. The Sicista specimen shows a morphological and morphometrical similarity to Sicista subtilis and it may represent the first record in Italy and the third in the whole Europe of the latter species. The discovery defines advancement in the Sicista paleogeography in the North of Italy and it certainly demonstrates that an important faunal migration during the Last Maximum Glacial involved the Western part of the Po valley, too.&nbsp

Comparison of Polyethylene Bubble Wrap and Corrugated Cardboard Traps for Sampling Tree-Inhabiting Spiders

In this paper, we studied the use of polyethylene bubble wrap and corrugated cardboard bark traps to sample spiders inhabiting tree trunks, with special reference to test whether they function the same way despite the differences in the spider community imposed by the different tree species and surroundings and times of sampling. The survey was carried out from July 1997 to July 1998 in Turin, Italy, in a green urban area on three poplars and four American basswoods. Differences between the two methods were tested in terms of abundance, diversity, dominance, mean body length of specimens, and proportion of juveniles, calculating Spearman's correlations. Three-factor analysis of variance, multiresponse permutation procedure, and indicator species analysis were used for further analysis. Results obtained by the two traps were correlated following a similar trend over sampling time. Bubble polyethylene seemed to be more effective than corrugated cardboard at trapping higher number of specimens. The dimension and total amount of interstices and the different microhabitat conditions of temperature and humidity seemed to be the main factors influencing spider composition in terms of the selected variables. On the basis of our results, polyethylene bark traps are recommended for sampling spiders living on trees. It is important to consider seasonality in experimental design, autumn being the period with the highest abundance of spiders but a lower level of diversity

Model Penerimaan Aplikasi BRISPOT BRI Unit Dengan Pendekatan Technology Acceptance Model (TAM)

BRISPOT is BRI's innovative step in Financial Technology (Fintech) services to accelerate the micro credit process, be more efficient, paperless and digital-based. This study analyzes the acceptance of the use of the BRISPOT application in BRI Kanca Karawang. One of the models used in analyzing technology acceptance is the Technology Acceptance Model (TAM). This research was conducted from December 2019 to February 2020. The population in this study amounted to 124 respondents with the criteria for respondents in this study were marketers who had used BRISPOT. Methods and data analysis using PLS-SEM. The results showed that perceived resources and self efficacy had a significant effect on perceived ease of use, perceived ease of use had a significant effect on perceived usefulness, perceived usefulness had a significant effect on attitude toward using, and attitude toward using had a significant effect on actual use of BRISPOT. The managerial implication in this research is that management can improve the upload feature of business photos and debtors' collateral and add the BRISPOT employee care feature to the application so that respondents can immediately ask questions and get solutions to problems with features that are experiencing interference. Keywords: BRISPOT, IPMA, PLS, TAM, sales marketin

Towards modelling beef cattle management with Genetic Programming

Abbona, F., Vanneschi, L., Bona, M., & Giacobini, M. (2020). Towards modelling beef cattle management with Genetic Programming. Livestock Science, 241, 1-12. [104205]. https://doi.org/10.1016/j.livsci.2020.104205Among the Italian Piemontese Beef Breedings, the yearly production of calves weaned per cow, that is the calves that survive during the period of 60 days following birth, is identified as the main target expressing the performance of a farm. modeling farm dynamics in order to predict the value of this parameter is a possible solution to investigate and highlight breeding strengths, and to find alternatives to penalizing factors. The identification of such variables is a complex but solvable task, since the amount of recorded data among livestock is nowadays huge and manageable through Machine Learning techniques. Besides, the evaluation of the effectiveness of the type of management allows the breeder to consolidate the ongoing processes or, on the contrary, to adopt new management strategies. To solve this problem, we propose a Genetic Programming approach, a white-box technique suitable for big data management, and with an intrinsic ability to select important variables, providing simple models. The most frequent variables encapsulated in the models built by Genetic Programming are highlighted, and their zoological significance is investigated a posteriori, evaluating the performance of the prediction models. Moreover, two of the final expressions selected only three variables among the 48 given in input, one of which is the best performing among GP models. The expressions were then analyzed in order to propose a zootechnical interpretation of the equations. Comparisons with other common techniques, including also black-box methods, are performed, in order to evaluate the performance of different type of methods in terms of accuracy and generalization ability. The approach entailed constructive and helpful considerations to the addressed task, confirming its key-role in the zootechnical field, especially in the beef breeding management.authorsversionpublishe

A GP approach for precision farming

Abbona, F., Vanneschi, L., Bona, M., & Giacobini, M. (2020). A GP approach for precision farming. In 2020 IEEE Congress on Evolutionary Computation, CEC : 2020 Conference Proceedings (pp. 1-8). [9185637] (2020 IEEE Congress on Evolutionary Computation, CEC 2020 - Conference Proceedings). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/CEC48606.2020.9185637Livestock is increasingly treated not just as food containers, but as animals that can be susceptible to stress and diseases, affecting, therefore, the production of offspring and the performance of the farm. The breeder needs a simple and useful tool to make the best decisions for his farm, as well as being able to objectively check whether the choices and investments made have improved or worsened its performance. The amount of data is huge but often dispersive: it is therefore essential to provide the farmer with a clear and comprehensible solution, that represents an additional investment. This research proposes a genetic programming approach to predict the yearly number of weaned calves per cow of a farm, namely the measure of its performance. To investigate the efficiency of genetic programming in such a problem, a dataset composed by observations on representative Piedmontese breedings was used. The results show that the algorithm is appropriate, and can perform an implicit feature selection, highlighting important variables and leading to simple and interpretable models.authorsversionpublishe

Adesão a uma cerâmica aluminizada densamente sinterizada e a uma cerâmica a base de alumina / zircônia infiltrada de vidro

The objective of this study was to test two hypotheses: (1) silica coating affects the bond strength between ceramics and a resin cement; (2) bond strength is affected by the type of ceramic. Twelve blocks 5 x 6 x 8 mm of In-Ceram Zirconia (ZR) and twelve Procera AllCeram (PR) ceramics were made and duplicated in composite. Five blocks of each ceramic were treated as follows: (1) ZR + GB (laboratorial airborne particles abrasion with Al2O3 particles) + silane; (2) ZR + SC (chairside tribochemical silica coating system, Cojet); (3) PR + GB; (4) PR + SC. Two treated samples of ceramic were analyzed under SEM. The ceramic-composite blocks were cemented with Panavia F and stored in 37ºC distilled water for 7 days. They were then cut to produce bar specimens (n=30) with a bonding area of 0.6±0.1mm². Specimens were loaded to failure under tension in a universal testing machine (1 mm/min). Bond strength (sigma) values were statistically analyzed using ANOVA (Two-way) and Tukey (alpha = 0.05). Mean sigma (MPa) and standard deviation were as follows: 1) 15.1 ± 5.3; 2) 26.8 ± 7.4; 3) 12.7 ± 2.6; 4) 18.5 ± 4.7. Silica coated surfaces showed statistically higher sigma than the same substrate treated with GB only. In addition, ZR (with vitreous phase) showed higher ó than PR (without vitreous phase).O objetivo deste estudo foi testar duas hipóteses: (1) a deposição de sílica afeta a resistência adesiva entre cerâmicas e cimento resinoso; (2) a resistência adesiva é afetada pelo tipo de cerâmica. Dez blocos (5 x 6 x 8 mm³) das cerâmicas In-Ceram Zircônia (ZR) e Procera AllCeram (PR) foram confeccionados e duplicados em resina composta. Cinco blocos de cada cerâmica foram assim tratados: (1) ZR + GB (jateamento com partículas de Al2O3) + silano; (2) ZR + SC (deposição de sílica/silanização - Sistema CoJet); (3) PR + GB; (4) PR + SC. Os blocos de cerâmica-compósito foram cimentados com Panavia F e armazenados em água destilada (37ºC / 7 dias). Eles foram então cortados para obter corpos-de-prova em forma de barras (n=30) com uma área adesiva de 0,6 ± 0,1mm². Os cp foram submetidos ao teste de microtração em uma máquina de ensaio universal (1mm.min-1). Os valores de resistência adesiva (sigma) foram submetidos à análise de variância (2 fatores) e ao teste de Tukey (alfa = 0,05). As médias de sigma (MPa) e os desvios padrão foram: 1) 15,1 (5,3); 2) 26,8 (7,4); 3) 12,7 (2,6); 4) 18,5 (4,7). A deposição de sílica na superfície cerâmica apresentou maior que o mesmo substrato tratado com GB. Além disso, ZR (com fase vítrea) apresentou maior sigma que PR (sem fase vítrea)

Bonding to densely sintered alumina- and glass infiltrated aluminum / zirconium-based ceramics.

The objective of this study was to test two hypotheses: (1) silica coating affects the bond strength between ceramics and a resin cement; (2) bond strength is affected by the type of ceramic. Twelve blocks 5 x 6 x 8 mm of In-Ceram Zirconia (ZR) and twelve Procera AllCeram (PR) ceramics were made and duplicated in composite. Five blocks of each ceramic were treated as follows: (1) ZR + GB (laboratorial airborne particles abrasion with Al2O3 particles) + silane; (2) ZR + SC (chairside tribochemical silica coating system, Cojet); (3) PR + GB; (4) PR + SC. Two treated samples of ceramic were analyzed under SEM. The ceramic-composite blocks were cemented with Panavia F and stored in 37ºC distilled water for 7 days. They were then cut to produce bar specimens (n=30) with a bonding area of 0.6±0.1mm². Specimens were loaded to failure under tension in a universal testing machine (1 mm/min). Bond strength (sigma) values were statistically analyzed using ANOVA (Two-way) and Tukey (alpha = 0.05). Mean sigma (MPa) and standard deviation were as follows: 1) 15.1 ± 5.3; 2) 26.8 ± 7.4; 3) 12.7 ± 2.6; 4) 18.5 ± 4.7. Silica coated surfaces showed statistically higher sigma than the same substrate treated with GB only. In addition, ZR (with vitreous phase) showed higher ó than PR (without vitreous phase)

Morphological abnormalities of diatom silica walls in relation to heavy metal contamination and artificial growth conditions

Teratological forms of diatoms are non-adaptive phenotypic abnormalities caused by various environmental stresses. Heavy metal contamination and artificial growth conditions are the best known causes. In fact, the recording of abnormal cells in a diatom population or community can give both a temporal and quantitative indication of heavy metal contaminationof water bodies. Moreover, long-term cultures generally present a high percentage of abnormal cells due to the scarcity of nutrients, presence of waste products and osmotic pressure. The aim of this paper is to classify and provide photographic documentation and descriptions of all known teratologies occurring in the most widespread freshwater diatom genera

Fertilization with different soil types in viticulture: a three-year experience in Trentino Alto Adige

6CO.NA.VI. 2020 – 8° Convegno Nazionale di Viticoltura, Udine, Italy, July 5-7, 2021openInternationalItalian coauthor/editorThe work aimed at investigating the impact of various good quality soils of on vineyard productivity. Manure matured with a fast and controlled process and compost obtained from digestate of an organic fraction of municipal solid waste (OFMSW) were applied one time on a grapevine row, in two CAVIT vineyards. A physico-chemical characterization of the soils was carried out and biological quality indices QBS-ar (Arthropodological Biocenosis) were calculated. The vegeto-productive monitoring was performed by foliar nutrients analysis and measuring NDVI and SPAD indices. The organic source had a significant fertilizing effect, especially manure, which determined a nutrient increase in soil (P, K and Mg), a rise in photosynthetically active biomass, available nitrogen and potassium in plants. The effects on the biological community of soils and musts quality were negligible. The use of soil improvers could be an efficient strategy for the nutrition of not vigorous vineyards, which do not require high nitrogen inputs.openPedò, Stefano; Bona, Daniela; Cristoforetti, Andrea; Ippolito, Marco; Porro, Duilio; Trainotti, DiegoPedò, S.; Bona, D.; Cristoforetti, A.; Ippolito, M.; Porro, D.; Trainotti, D