Dry granular flows: micromechanical interpretation of impacts on rigid obstacles.

The evaluation of impact forces exerted by flowing granular masses on rigid obstacles is of fundamental importance for the assessment of the associated risk and for the design of protection measures. A number of formulae are available in the literature for the maximum impact force; most of them are based on oversimplifying hypotheses about the behaviour of the granular material. For practical applications, formulations based on either hydrodynamic or elastic body models are often employed. These formulations require the use of empirical correcting factors. In order to better understand the impact mechanics, the authors have recently performed an extensive numerical campaign by using a Discrete Element approach (PFC3D code), where a dry granular mass is represented as a random distribution of rigid spherical particles. A new design formula, combining the hydrodynamic and elastic body theories, has been proposed on the base of the results obtained at the macroscopic scale. The parameters of the formula have been correlated with geometrical factors, namely front inclination and flow height. In this paper, the same DEM model is further used in order to investigate the relationship between the evolution with time of the impact force and the micromechanics of the granular mass. In particular, information about contact forces and particle velocities will be discussed and critically compared with macroscopic results. In order to progressively introduce the complexity of the impact phenomenon, three geometrical conditions are considered: a) vertical front, confined flow; b) vertical front, free surface flow; c) inclined front, free surface flow

Intermodal vs. conventional logistic of refrigerated products: a case study from Southern to Northern Europe

Most of perishable goods, such as fruit and vegetables, are transported in Europe by truck and clogging up the main road networks. The increasing demand for freight transport and the environmental concerns all indicate the necessity to embrace new means of transport such as the intermodal one. The intermodal transport uses swap bodies and reefer containers that allow for the use of interchangeable truck, train, and ship to reduce direct and external costs. Nowadays, the utilization of exclusive truck transport is due to its considerable flexibility and often to the disregard of the motor vehicle regulations during transport. This research aims to analyze some essential readjustments that must be made in order to increase efficiency in the logistic of refrigerated fruit and vegetables. To do so, some hypotheses were analyzed and formulated in which the strategic use of the truck was recognized and inserted as part of an intermodal transport system. The transport options of a combined use of ships and trains in association with trucks were evaluated with respect to the current prevalent solution of exclusive use of trucks. Such options were evaluated by comparing them under different itineraries hypotheses (from south Italy, Sicily to Germany, Munich) on the base of costs and transit-times parameters. This was done mainly throughout interviewing sector-relevant transport operators. The results of the comparison between the intermodal and conventional transport was shown to be economically more convenient with respect to both legal and illegal transport by exclusive truck transport, presenting lower per unit costs (swap body or semi-trailer, containing the same amount of goods). Moreover, the intermodal solution scores equal or higher transit times in the comparison with the “transit by regulation compliance” and much higher transit times if compared with the “illegal” option. Therefore, the regulation compliance aspect would partially promote the use of intermodal options in a future fair competition. In addition, besides reducing the direct costs, it produces several other positive effects in terms of external costs to the society such as to reduce road crashes, noises, atmospheric emissions and greenhouse effect. A more efficient system should plan an integrated system of arrival and departure organizing together the schedules of ships and trains dedicated to perishable goods and increasing the transported amounts. Furthermore, another idea is to stipulate commercial agreements with train operators, applying a reduction on the base price, by ensuring the delivery of a block train for an arranged period.   Keywords: Intermodal, freight logisticcentre, truck haulage, rail hub; terminal

On the Role of Electric Charge and Cosmological Constant in Structure Scalars

The physical meaning of structure scalars is analyzed for charged dissipative spherical fluids and for neutral dust in the presence of cosmological constant. The role played by such factors in the structure scalars is clearly brought out and physical consequences are discussed. Particular attention needs to be paid to the changes introduced by the above mentioned factors in the inhomogeneity factor and the evolution of the expansion scalar and the shear tensor.Comment: 5 pages Latex. Published in Phys. Rev. D. Some typos correcte

Why does gravitational radiation produce vorticity?

We calculate the vorticity of world--lines of observers at rest in a Bondi--Sachs frame, produced by gravitational radiation, in a general Sachs metric. We claim that such an effect is related to the super--Poynting vector, in a similar way as the existence of the electromagnetic Poynting vector is related to the vorticity in stationary electrovacum spacetimes.Comment: 9 pages; to appear in Classical and Quantum Gravit

Curcumin Modulates Nitrosative Stress, Inflammation, and DNA Damage and Protects against Ochratoxin A-Induced Hepatotoxicity and Nephrotoxicity in Rats.

Ochratoxin A (OTA) is a fungal toxin of critical concern for food safety both for human health and several animal species, also representing a cancer threat to humans. Curcumin (CURC) is a natural polyphenol that has anti-apoptotic, anti-inflammatory, and antioxidant effects. The aim of this study was to investigate the cytoprotective effect of CURC against OTA-induced nephrotoxicity and hepatotoxicity through the study of the nitrosative stress, pro-inflammatory cytokines, and deoxyribonucleic acid (DNA) damage. Sprague Dawley rats were daily treated with CURC (100 mg/kg b.w.), OTA (0.5 mg/kg b.w), or CURC with OTA by oral gavage for 14 days. Our results demonstrated that OTA exposure was associated with significant increase of pro-inflammatory and DNA oxidative-damage biomarkers. Moreover, OTA induced the inducible nitric oxide synthase, (iNOS) resulting in increased nitric oxide (NO) levels both in kidney and liver. The co-treatment OTA + CURC counteracted the harmful effects of chronic OTA treatment by regulating inflammation, reducing NO levels and oxidative DNA damage in kidney and liver tissues. Histology revealed that OTA + CURC treatment determinates mainly an Iba1+ macrophagic infiltration with fewer CD3+ T-lymphocytes in the tissues. In conclusion, we evidenced that CURC exerted cytoprotective and antioxidant activities against OTA-induced toxicity in rats

Biometrics measurements in Red foxes (Vulpes vulpes) in the Picentini area. Discussion and conclusions

Techniques for assigning individual to age-classes and/or distinguish between sexes are necessary to understand population dynamics and behavioral interactions of Red foxes (Vulpes vulpes). Many studies have focused on separating juveniles from adults; age of captured live pups can be estimated from morphological changes, hind foot (HF) length, zygomatic (Z) width and body weight1. Methods that avoid capturing the animals would be particularly useful, but none is available. In this paper biometric differences between young adults and adults subjects and between sexes are investigated. Lower canine length (LCL), lower canine width (LCW), condilo-basal (CB) and scapular length resulted smaller than female adults, whereas male young adults had withers height, occipito-coccygeal (OC), ear length, and upper canine width (UCW) smaller than male adults. Almost all the parameters included in this study confirmed sexual dimorphism and some of the differences already present in young adults gained significance (from P<0.05 to P<0.01) in the adult foxes. In particular bodyweight, OC length, withers height, ear length, upper canine length and LCL, scapular and mandibular length, and inter-carnassial (IC) and Z width were significantly greater in male than in female adult foxes (P<0.01). Nasal-occipitalis (NO) length, total length, UCW and LCW, and upper dentition (UD) were significantly greater in male than in female adult foxes, as well (P<0.05). The low number of subjects included in each category, strictly due to hunting season, did not allow estimating an accurate range for the biometrics measurements performed and probably biased recordings, producing some contradictory results. Fox size varies geographically, thus mean adults measurements should be determined for each area in which they have to be applied1. HF method has been demonstrated to be an accurate method for assessing age of pups1; our data suggest that it might be as efficient in young adults, at least in female subjects. On the other hand, our results confirm the sexual dimorphism in the canine region to be higher than in the carnassial region (data not shown in our results)

Perosomus elumbis in piglets: Pathological, radiological and cytogenetic findings

Perosomus elumbis (PE) is a rare congenital condition characterized by agenesis of the lumbar, sacral and coccygeal vertebrae. Perosomus elumbis has rarely been reported in literature as morphological description of singles or few cases. Here we report the first extensive description of eight cases of PE detected in two consecutive litters from the same parents of Casertana pig breed. In August 2018, eight piglets were investigated for multiple malformations. All malformed animals, but one, died in the first day of life. The survivor piglet died at 23 days of age. Pathological, radiological and cytogenetic examination was performed. Furthermore, a farm epidemiological investigation was carried out to investigate the percentage of piglets born dead or with malformations in 2018. The radiological and pathological exams showed skeletal abnormalities at the spinal cord level and visceral malformations. Cytogenetic investigations showed a normal chromosome arrangement. Finally, epidemiological investigation revealed a low prevalence of malformations in newborn pigs, equal to 0.5% of the total birth rate of the farm. Our findings report the first extensive description of PE cases in pigs and suggest an underestimation of this malformation in veterinary medicine. Our findings also suggest a specific genetic etiological basis as cause of PE in pigs and exclude chromosomal abnormalities. Further studies will be performed to confirm this hypothesis

Angiostrongylus vasorum infection in red foxes (Vulpes vulpes) in southern Italy

Angiostrongylus vasorum (Nematoda: Angiostrongylidae) infection was detected at post-mortem examination in the pulmonary arteries and hearts of 34/102 (33,3%) of red foxes (Vulpes vulpes) from the Campania Region in southern Italy. Pathological changes consisted of granulomatous interstitial pneumonia caused by larvae and intravascular pulmonary adult nematodes. These changes confirm that angiostrongylosis infection in red foxes has a mainly chronic course, in which the infected host may disperse parasite larvae in the environment over its lifetime. Results suggest that the life cycle of A. vasorum is well established in the red fox in the Campania Region representing a potential infection risk for dogs

Full Causal Bulk Viscous Cosmologies with time-varying Constants

We study the evolution of a flat Friedmann-Robertson-Walker Universe, filled with a bulk viscous cosmological fluid, in the presence of time varying ``constants''. The dimensional analysis of the model suggests a proportionality between the bulk viscous pressure of the dissipative fluid and the energy density. On using this assumption and with the choice of the standard equations of state for the bulk viscosity coefficient, temperature and relaxation time, the general solution of the field equations can be obtained, with all physical parameters having a power-law time dependence. The symmetry analysis of this model, performed by using Lie group techniques, confirms the unicity of the solution for this functional form of the bulk viscous pressure. In order to find another possible solution we relax the hypotheses assuming a concrete functional dependence for the ``constants''.Comment: 28 pages, RevTeX