Inertia compensation while scanning screw threads on coordinate-measuring machines

Usage of scanning coordinate-measuring machines for inspection of screw threads has become a common practice nowadays. Compared to touch trigger probing, scanning capabilities allow to speed up measuring process while still maintaining high accuracy. However, in some cases accuracy drasticaly depends on the scanning speed. In this paper a compensation method is proposed allowing to reduce the influence of some dynamic effects while scanning screw threads on coordinate-measuring machines

Investigation of sandy soil dynamic strength by the method of self-excited vibration

© SGEM 2017. This paper presents a new approach to the evaluation of dynamic soil strength based on the hypothesis of discreteness of the deformation process - a method of self-excited vibration. This method was first discovered at the sandy soil shear test. The destruction of the soil is viewed as cyclical and consists of two phases: the static and dynamic. On static stage deformation is slow, with energy accumulation. In the dynamic there is a rapid discharge, accompanied by a sharp increase in strain. Self-excited vibrations (which can be named auto oscillation) are caused by the fact that the soil accumulates potential energy only up to a certain limit, which depends on its density, and then there is the destruction of soil structure, the instantaneous relaxation of shear resistance and plastic deformation slip. Thereafter, under the influence of an external load soil again accumulates energy gradually, and then being unloaded. Strength parameters (angle of sliding friction φf, the angle of gearing φ с and soil’s fractions connection Z w ) defined at each stage, take into account the kinetics of the process of destruction and are proposed as dynamic soil strength parameters

Regularities of slope processes forming on the “kazan“ ski complex area (russia)

© SGEM 2014. In the beginning of the 21 century, on the right bank of the Sviyaga river, the building up of the sport ski complex “Kazan” was organized and almost at once after that, an active landslides with considerable shifts of the soil began to happen. Previous researches were based on the conventional geology aspects of this area-sub horizontal deposits of Permian measures. Thus the critical angle and nature of the formed landslides are absolutely did not correspond to the typical destruction of rock massive of the area nearby. Our researches showed that on the area of sport ski complex, the geological aspect is absolutely different. Permian measures have an “invention” and considerably folded. It can testified to that we have a deal with an old landslide, forming of which had started in the period of late Neo-Pleistocene with the beginning of the depositing of the right flowing of Sviyaga river-Sulitsa river. In this work are presented the results of a comprehensive assessment of landslides danger on that area, which are based on a large volume of field and laboratory researches. As a result it was established that one of the reason of the landslides developing (not determinate during previous researches) is a strong dislocation and durability loss of carbonate and terrigene Permian measures. Therefore at calculation of stability of slopes it is necessary to consider possibility of formation of a circular cylindrical surface of sliding, by analogy to disperse soil. Mechanical properties of massive material have to be defined taking into account their fracturing. Also conducted researches led to revision of the earliest wrong ideas of a geological structure of this area and to make correction of geological maps

Approximate algorithms for minimization of binary decision diagrams on the basis of linear transformations of variables

Algorithms for an approximate minimization of binary decision diagrams (BDD) on the basis of linear transformations of variables are proposed. The algorithms rely on the transformations of only adjacent variables and have a polynomial complexity relative to the size of the table that lists values of the function involved

Modeling thermal treatment in combination with acid treatment of a multilayer oil reservoir

© 2015 Springer Science+Business Media New York. The problem of combined thermal and acid treatment in a multilayer crude-oil reservoir is examined for two-phase flows of fluid (water and crude oil) in a porous medium. A model in the form of a "bundle" of cylindrical capillaries of different radii is used to describe changes in the porosity and permeability of the porous medium as a result of chemical reaction between the acid and rock matrix, and the coalescence rate of the channels due to dissolution of pore walls is calculated based on the Smoluchowski equation. The recovery of crude oil in conventional flooding is compared with flooding with injection of a heat-transfer agent, and flooding using acid and the combination technology. It is shown that thermal treatment combined with acid treatment of a multilayer crude-oil formation provides the most effective oil production conditions

Feasibility of needle and syringe programs in Tajikistan distributing low dead space needles

Background In 2012, the World Health Organization recommended that needle and syringe programs offer their clients low dead space insulin syringes with permanently attached needles. However, in many countries, these syringes are not acceptable to a majority of people who inject drugs. This study assessed the feasibility of working with needle and syringe programs to implement the WHO recommendation using low dead space detachable needles. The study also assessed the acceptability of the needles. Methods Two needle and syringe programs in Tajikistan—one in Kulob and one in Khudjand—received 25,000 low dead space detachable needles each. The programs distributed low dead space detachable needles and a marketing flyer that emphasized the relative advantages of the needles. Each program also enrolled 100 participants, and each participant completed a baseline interview and a 2-month follow-up interview. Results At follow-up, 100% of participants reported trying the low dead space detachable needles, and 96% reported that they liked using the needles. Both needle and syringe programs distributed all their needles within the first 60 days of the project indicating use of the needles, even among clients who did not participate in the study. Conclusions This project demonstrates that it is feasible for needle and syringe programs to offer and promote low dead space needles to their clients. The findings indicate that low dead space needles are acceptable to needle and syringe program clients in these Tajikistan cities. To reduce HIV and hepatitis C virus transmission, needle and syringe programs should offer low dead space needles, low dead space insulin syringes in addition to standard needles, and syringes to their clients

Optimization of a heralded single-photon source with spatial and temporal multiplexing

© Published under licence by IOP Publishing Ltd. The properties of a heralded single-photon source with temporal and spatial multiplexing are studied with the aim to maximize its efficiency for a given value of the second-order zero-time autocorrelation function. We show that the variable time delay, which is used for temporal multiplexing, can be optimized so that the mean number of photon passes through the switches and the total number of switches are respectively reduced to ∼ log2N and ∼ (1/2)log2N, where N is the temporal multiplexing degree. The total efficiency of such an optimized source is calculated for typical switching losses and the autocorrelation function is calculated in the presence of the detector dark-count noise

Using plaxis software for the forecasting of karst-suffusion failures in carbonate eluvium

© SGEM2017. All Rights Reserved. Carbonate eluvium is suffusion unstable soil, where voids and cavities can be formed. This can lead to adverse effects and disasters in the constructions of buildings and structures. This article presents the results of using the Plaxis Software for the determination of the critical depth and critical diameter of the cavities in which the possible collapse. The total thickness of the carbonate eluvium exceeds twenty meters in the study area. The calculation model of the cavity growth included the geometric model of engineering and geological section, complete with physical and mechanical properties (density, internal friction angle, cohesion, modulus of deformation). The cavity was modeled in the form of two nested cylinders. Internal is a cavity, external - weakened soil zone. This approach revealed that in the studied area the dangerous depth is up to seven-eight meter, and the average value of the critical diameter is about two meter. And the most dangerous for the construction of the building will be the appearance of the cavity under a corner of the building. The research results showed good agreement with the actual observed failures in the study are