Promotion of Tunneling Performance in Locally Semi-Hard to Hard Conglomerate Lenses, Case of Esfahan Historical City Subway Project

The highly inhomogeneous nature of the river deposits in central Esfahan induced unforeseen problems for tunneling of 2×5 km long of middle section of the Esfahan Subway Project. A noticeable phenomenon in these course grained fluvial (river) deposits is the locally cementation of the soil particles by a calcium carbonate binder and formation of some semi-hard to hard conglomerate lenses. This unique phenomenon is named locally as “Sovord” rock and could be seen just in semi-aired regions as central Iran. Two 6.89 m diameter EPBTBM machines were employed to excavate shallow tunnels in the vicinity of fragile structures of the old city. The main unwanted impacts of this highly cohesive pseudo-rock were noticed as high vibration, temperature raising, tunnel face instability, low rate of machine’s advance, early tools damage and finally great cutter-head damage after the first major collision with this unpredicted phenomenon. We analyzed geotechnical characteristics of this material and the corresponding effects on face supporting pressure, foaming agents, soil conditioning process and operational policy. Lowering the cylinder thrust force, ≤9000KN, improving the cutting wheel rotation speed, ≥2.5RPM, using some anti-abrasive foaming agents, ABR2 lubricants, and periodic tools inspection schedule was considered as solution for the indicated problem

Investigation into Airborne Dust ina Wool Textile Mill

Airborne dust samples were gathered from the vicinity of various commonly performed processes in the wool-preparation industry. Samples of airborne wool dust were collected on membrane filters during the processing of wool lots. The chemical composition of the inorganic particles present in the total inspirable and respirable dust fractions was determined with the use of a Scanning Electron Microscope (SEM). The widely differing morphologies of the particles collected raise questions about the validity of trying to correlate minor respiratory symptoms with dust concentrations, as some particle types will penetrate the respiratory system more easily than others. The results are discussed with respect to the sampling methodology used

A Mathematical Approach for Evaluation of Surface Topography Parameters

The probability characteristics of surface topography parameters described by the composition of the deterministic component and the homogeneous random normal field were analysed. Formulae for the calculation of the mathematical expectation of the Ras parameter and the evaluation of its variance are given

A Mathematical Model of theDrying Process

A convective drying model is proposed which may be used to describe the drying behavior of leather. Using this model, the calculated transient leather temperature agrees well with experimental values. Variations in temperature and moisture content distribution are solved using the finite-difference method. The effects of operation parameters, such as temperature and humidity in the dryer, initial moisture content of the leather, and heat and mass transfer coefficients are examined using the model

Experimental Investigations on Drying of Porous Media Using Infrared Radiation

Increased interest is being shown in infrared drying today because of the environmental and technological advantages offered by this method. In order to assess the advantages of this drying process, extensive trials have been carried out. The objective of this investigation was to study the drying rate of infrared drying. This was achieved with the use of scanning pyrometer and image analysis.

The family pictures of our neighbours: investigating the mass function and dynamical parameters of nearby open clusters

We determine the mass functions (MFs) and the dynamical parameters of 15 nearby open clusters (OCs) using the unprecedented data set of the Gaia Early Data Release 3. We select the members of each cluster by combining the photometric (colour and magnitude) and astrometric (parallax and proper motions) parameters of stars, minimizing the contamination from Galactic field interlopers. By comparing the observed distribution of stars along the cluster main sequence with the best-fitting synthetic population, we find the present-day MF and the binary fraction of the OCs, along with their dynamical parameters like mass, half-mass radius, and half-mass relaxation time. We found that the global present-day MF of OCs are consistent with a single power-law function, $F(m)\propto m^\alpha$, with slopes $-3<\alpha<-0.6$ including both subsolar, $0.2<m/\text{M}_\odot<1$, and supersolar mass regimes. A significant correlation between the MF-slope and the ratio of age to half-mass relaxation time is evidenced, similarly to the same conclusion already observed among Galactic globular clusters. However, OCs evolve along different tracks in comparison with the globular clusters, possibly indicating primordial differences in their initial mass function (IMF). The comparison with Monte Carlo simulations suggests that all the analysed OCs could have been born with an IMF with slope $\alpha_{\text{IMF}}<-2.3$. We also show that the less evolved OCs have a MF consistent with that of the solar neighbourhood, indicating a possible connection between the dissolution of OCs and the formation of the Galactic disc.Comment: 20 pages, 14 figures, accepted for publication by MNRA