La lavorazione della lana in età romana: gli indicatori archeologici dalla provincia di Brescia

Some archaeological finds potentially related to wool production and its processing come from the province of Brescia. A relevant number of tools probably used for sheep shearing found in the sites of mountain valleys and in the southern lowlands can be counted among them. Spinning tools are mainly rappresented by spindle whorls whose weight could be functional for the production of medium or medium-large yarn. All spinning tools are often discovered in funerary areas of the territory. The catalogued loom-weights are recorded especially in the south-eastern plain and come from territorial settlements identified as probable rustic buildings or villae. Most of the collected loom-weights are shaped like a truncated pyramid with a round head and they also reveal a very high weight perhaps connected to the production of heavy wool fabrics. Finally stone loom-weights have been documented in settlements subject to the process of Romanization and located only in Valle Camonica

Specific heat and magnetization of a ZrB12 single crystal: characterization of a type II/1 superconductor

We measured the specific heat, the magnetization, and the magnetoresistance of a single crystal of ZrB12, which is superconducting below Tc ~ 6 K. The specific heat in zero field shows a BCS-type superconducting transition. The normal- to superconducting-state transition changes from first order (with a latent heat) to second order (without latent heat) with increasing magnetic field, indicating that the pure compound is a low-kappa, type-II/1 superconductor in the classification of Auer and Ullmaier [J. Auer and H. Ullmaier, Phys. Rev.B 7, 136 (1973)]. This behavior is confirmed by magnetization measurements. The H-T phase diagram based on specific-heat and magnetization data yields Hc2(0) =550 G for the bulk upper critical field, whereas the critical field defined by vanishing resistance is a surface critical field Hc3(0) ~ 1000 G.Comment: 17 pages, 8 figures, submitted to PR

Anomalous charge transport in dodecaborides RB12 (R- Ho, Er, Tm, Lu)

High precision measurements of Hall RH(T) and Seebeck S(T) coefficients have been carried out for the first time on single crystals of rare earth dodecaborides RB12 (R - Ho, Er, Tm, Lu) at temperatures 1.8 - 300K. Low temperature anomalies associated with antiferromagnetic phase transitions in HoB12, ErB12 and TmB12 compounds have been detected on the temperature dependencies of RH(T) and S(T). The estimated values of charge carriers mobility allowed us to conclude about the appreciable influence of spin fluctuations on the charge transport in these compounds with B12 atomic clusters

Effect of moisture on nitrogen dioxide formation in laminar flame of natural gas

The paper contains the results of experimental studies of the effect of moisture on nitrogen dioxide formation and on oxidation of NO to NO2 in laminar premixed flame of natural gas. The water vapor is shown to be the third very influential participant, along with fuel and oxidizer, in the combustion process. Injection of moisture into the combustion zone has an effect due to the insertion of additional quantities of HO2- and OH– radicals into the process, which contributes to the intensification of the oxidation of NO to NO2. Introduction of the concept of the “excess moisture ratio” in the combustion process is proposed.  The studies were executed at the laboratory installation in conditions of formation of the V-shaped laminar flame of natural gas behind a transverse cylindrical steel stabilizer, with determining the concentrations of flue gas components

Comportement du ballast sous l'action du bourrage et du trafic ferroviaire

The geometry of the railway track is degraded under traffic load, and must be maintained periodically. This degradation is due to the arrangement of ballast particles under loads and vibrations, which results into irreversible plastic settlements. Tamping is a procedure of maintenance, used to restore the correct geometrical position of the ballasted tracks. However, the penetration of the vibrating tines into the ballast causes an increase in the fine particles content by rupture of the edges of the grains and leads to a progressive degradation of the ballast and thus to a loss of its mechanical properties. The main consequence is that the interval between two tamping operations decreases, along with the long-term effectiveness of the process. This vicious circle can be broken only by ballast renewal. Ballast and geometry maintenance represent 40 to 50% of the total railway maintenance budget during lifetime. The goal of this research is a better understanding of ballast degradation and the development of a tool to evaluate the effectiveness of the track tamping, according to the ballast condition and the infrastructure stiffness. This knowledge will make it possible to decrease the destroying effects of tamping over ballast and, consequently, increase the durability of track geometry and ballast. A full-scale laboratory study has been done on ballasts and infrastructures of different qualities. The dynamic loading of freight trains is simulated with a big hydraulic actuator, while the deformations of the track and his infrastructure are continuously measured. The accelerated loading corresponds to a period of 20 years of traffic operation on a high loaded line. Empirical settlement laws are written, based on the traffic results. Tamping process is performed with a special machine, which was built by purpose. The parameters to regulate tamping process can be controlled. The whole process and the equipment are completely instrumented, in order to control and measure several parameters in real time. The evolution of the ballast behaviour is analysed with the measurement of the bearing modulus. Plate load tests are performed under specially equipped sleepers, after each traffic cycle and tamping. The parameters of a new tamping are tested. The short and long-term effects on ballast are analysed and discussed. A two-dimensional finite element model has been applied to simulate the response of the ballast layer under traffic loading, and the development of settlements. Ballast at different degradation levels is studied. The influence of the subgrade stiffness is also taken in account. The elastoplastic Hujeux behaviour law is applied, in order to study the cyclic plasticity. Results are presented and the critical zones, which show the most plastic behaviour, are identified. A phenomenological model is also developed to analyse separately the effects of traffic loading and track tamping on ballast behaviour and degradation. This analysis is based on a backcalculation approach, and is performed on a 3-D finite elements model of the track. The Young modulus of the ballast and the infrastructure layers in situ is calculated by iteration. Along with the traffic simulation, the evolution of the ballast elastic modulus is measured. A comparison between two sections with different infrastructures is done

Best Practice in Surgical Treatment of Malignant Head and Neck Tumors

Purpose of review: Defining the best practice of surgical care for patients affected by malignant head and neck tumors is of great importance. In this review we aim to describe the evolution of “best practice” guidelines in the context of quality-of-care measures and discuss current evidence on “best practice” for the surgical treatment of cancers of the sino-nasal tract, skull base, aero-digestive tract, and the neck. Recent findings: Current evidence based on certain structure and outcome indicators, but mostly based on process indicators already helps defining the framework of “Best practice” for head and neck cancer surgery. However, many aspects of surgical treatment still require in-depth research. Summary: While a framework of “Best practice” strategies already exists for the conduction of the surgical treatment of head and neck cancers, many questions still require additional research in particular in case of rare histologies in the head and neck region