ROCK SURFACE CHARACTERIZATION BY IMMERSION CALORIMETRY: WETTABILITY AND SPECIFIC SURFACE AREA

ABSTRACT Petrophysical properties such as wettability and surface area control hydrocarbon storage and transport properties. In the work being reported in this paper, we present the theoretical aspects as well as experimental technique and results of testing and validating a proposed calorimetry technique for specific surface area and wettability characterization. Identical immersion calorimetry experiments with slightly different initial conditions of the sample are analyzed to obtain these two properties of a core sample. Validation of the experimental technique is an important step, which is performed in this work by comparing the surface areas of the samples obtained by the proposed technique with the surface area obtained by the well-known Brunauer-EmmettTaylor (BET) gas-adsorption technique. Surface area measurements are performed on a set of core plugs and reference samples, including hydrophilic and hydrophobic powders of pure substances, minerals, and clays

NUMERICAL MODELING OF A STRESS-STRAIN STATE OF A GAS PIPELINE WITH COLD BENDING OFFSETS ACCORDING TO IN-LINE INSPECTION

Knowledge of the current stress-strain state of any section of the pipeline allows you to make informed decisions on its operation, maintenance and repair, as well as on the prediction of the technical condition. The task of determining the characteristics of the stress-strain state of a gas pipeline section that has cold bend offsets (CBO) according to in-line inspection (ILI) is considered. The bent part of CBO is characterized by the presence of residual stresses and deformations in the wall of the offset, which contribute to the overall level of the stress-strain state of the gas pipeline operating under external and internal loads. Using the results of in-line diagnostics, numerical modeling and a solution, the change in the values of longitudinal stresses, is determined and the need to take into account residual stresses in the zone of elastic-plastic deformations of cold bend offsets is shown

Estimates in Beurling--Helson type theorems. Multidimensional case

We consider the spaces $A_p(\mathbb T^m)$ of functions $f$ on the $m$ -dimensional torus $\mathbb T^m$ such that the sequence of the Fourier coefficients $\hat{f}=\{\hat{f}(k), ~k \in \mathbb Z^m\}$ belongs to $l^p(\mathbb Z^m), ~1\leq p<2$. The norm on $A_p(\mathbb T^m)$ is defined by $\|f\|_{A_p(\mathbb T^m)}=\|\hat{f}\|_{l^p(\mathbb Z^m)}$. We study the rate of growth of the norms $\|e^{i\lambda\varphi}\|_{A_p(\mathbb T^m)}$ as $|\lambda|\rightarrow \infty, ~\lambda\in\mathbb R,$ for $C^1$ -smooth real functions $\varphi$ on $\mathbb T^m$ (the one-dimensional case was investigated by the author earlier). The lower estimates that we obtain have direct analogues for the spaces $A_p(\mathbb R^m)$

Assessment of internal pressure effect, causing additional bending of the pipeline

Article justifies accounting for internal pressure effect in the pipeline, causing additional bending of the pipeline. According to some scientists, there is an erroneously used concept of the equivalent longitudinal axial force (ELAF) Sx, which depends on working pressure, temperature stresses, and joint deformations of pipelines with various types of soils. However, authors of the article use ELAF Sx concept at construction of mathematical model of stress-strain state (SSS) for complex section of the trunk pipeline, and also reveal it when analyzing the results of calculating the durability and stability of the pipeline. Analysis of SSS for calculated section of the pipeline was carried out for two statements of the problem for different values of operation parameters. In the first statement, effect of internal pressure causing bending of the pipeline is taken into account, and in the second it is neglected. It is shown that due to effect of ELAF Sx at p0 = 9.0 MPa, Dt = 29 °C extreme value of bend increases by 54 %, extreme values of bending stresses from span bending moment increase by 74 %, and extreme value of bending stresses from support bending moment double with regard to corresponding SSS characteristics of the pipeline. In case of neglecting the internal pressure effect causing additional bending of the pipeline (second statement of the problem), error in calculating the extreme value of bend is 35 %, extreme value of bending stresses from span bending moments is 44 %, and extreme value of bending stresses from support bending moments is 95 %

ENERGY EFFICIENCY IMPROVEMENT OF SMALL HEAT OUTPUT HOT-WATER BOILERS

Article describes some boiler construction solutions for hot-water boilers of small heat output that give together with reliability improvement get the increase of boilers’ efficiency. Experiments approved that usage of bi-radiated furnace screens in KVa series boilers can give from 70.5 to 72.2 % of all heat power of the boiler. KVa-0.1 hot-water boiler thermal tests results showed that boiler’s efficiency rate on nominal power output is 93.12 %. Thermal tests of KSGn-0.63 and KSGn-1.16 boiler with bi-radiated screens approved that the efficiency rate on “small fire” mode is about 93 % and on nominal power output is about 92 %.В работе представлены некоторые конструктивные решения для водогрейных котлов малой мощности, позволяющие, наряду с повышением надежности водогрейных котлов, повысить их эффективность. Экспериментально получено, что использование двусветных экранов в котлах КВа позволяет снимать от 70,5 до 72,2 % от общей тепловой мощности котла. Результаты испытаний водогрейного котла КВа-1,0 показали, что КПД котла при расчетной нагрузке составил 93,12 %. Теплотехнические испытания котлов КСГн-0,63 и КСГн-1,16 с двусветными экранами показали, что КПД котлов на малом горении составляли порядка 93 %, а на нагрузках, близких к номинальным, порядка 92 %

Orbital effects of a monochromatic plane gravitational wave with ultra-low frequency incident on a gravitationally bound two-body system

We analytically compute the long-term orbital variations of a test particle orbiting a central body acted upon by an incident monochromatic plane gravitational wave. We assume that the characteristic size of the perturbed two-body system is much smaller than the wavelength of the wave. Moreover, we also suppose that the wave's frequency is much smaller than the particle's orbital one. We make neither a priori assumptions about the direction of the wavevector nor on the orbital geometry of the planet. We find that, while the semi-major axis is left unaffected, the eccentricity, the inclination, the longitude of the ascending node, the longitude of pericenter and the mean anomaly undergo non-vanishing long-term changes. They are not secular trends because of the slow modulation introduced by the tidal matrix coefficients and by the orbital elements themselves. They could be useful to indepenedently constrain the ultra-low frequency waves which may have been indirectly detected in the BICEP2 experiment. Our calculation holds, in general, for any gravitationally bound two-body system whose characteristic frequency is much larger than the frequency of the external wave. It is also valid for a generic perturbation of tidal type with constant coefficients over timescales of the order of the orbital period of the perturbed particle.Comment: LaTex2e, 24 pages, no figures, no tables. Changes suggested by the referees include

Inferring possible magnetic field strength of accreting inflows in EXor-type objects from scaled laboratory experiments

Aims. EXor-type objects are protostars that display powerful UV-optical outbursts caused by intermittent and powerful events of magnetospheric accretion. These objects are not yet well investigated and are quite difficult to characterize. Several parameters, such as plasma stream velocities, characteristic densities, and temperatures, can be retrieved from present observations. As of yet, however, there is no information about the magnetic field values and the exact underlying accretion scenario is also under discussion. Methods. We use laboratory plasmas, created by a high power laser impacting a solid target or by a plasma gun injector, and make these plasmas propagate perpendicularly to a strong external magnetic field. The propagating plasmas are found to be well scaled to the presently inferred parameters of EXor-type accretion event, thus allowing us to study the behaviour of such episodic accretion processes in scaled conditions. Results. We propose a scenario of additional matter accretion in the equatorial plane, which claims to explain the increased accretion rates of the EXor objects, supported by the experimental demonstration of effective plasma propagation across the magnetic field. In particular, our laboratory investigation allows us to determine that the field strength in the accretion stream of EXor objects, in a position intermediate between the truncation radius and the stellar surface, should be of the order of 100 G. This, in turn, suggests a field strength of a few kilogausses on the stellar surface, which is similar to values inferred from observations of classical T Tauri stars

Achene slime content in some taxa of Matricaria L. (Asteraceae)

The achenes of Matricaria aurea and two varieties of M. chamomilla (var. chamomilla and var. recutita) have slime cells on the surface and they are characterized by slime envelope formation during hydration. The slime in these taxa is composed of pectins and cellulose. The slime could play important role in the distribution and colonisation of new habitats in Matricaria taxa