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Shengli Oilfield has abundant oil and gas resources， with multiple types of reservoirs， and logging evaluation plays an essential role in exploration and development. The development history and the characteristics of logging evaluation technologies for reservoirs were systematically reviewed to celebrate the institute's 60th birthday. Summarizing experience and predicting the future have positive significance for the development and application in the professional logging field. A series of mature evaluation technologies formed in three types of reservoirs， including conventional sandstone reservoirs， complex reservoirs， and unconventional shale reservoirs， were systematically summarized according to the characteristics and evaluation difficulties of reservoirs. For conventional sandstone reservoirs， a highly applicable identification technology for oil layers was systematically developed， and an innovative method for establishing electrical standards constrained by the lower limits of lithology and oil potential was developed under multi-layer joint testing conditions. In addition， a pioneering logging modeling technology was proposed based on different diagenetic zones. Various technologies were developed for complex reservoirs， including logging identification of sandstone lithology in steep slope zones， effectiveness evaluation of low-permeability sandstone reservoirs， and identification and evaluation of oil layers with low resistivity. For unconventional shale reservoirs， a logging evaluation technology of reservoir parameters was preliminarily developed to evaluate the storage properties and oil potential mainly based on two-dimensional nuclear magnetic resonance experiments. These logging evaluation technologies for different types of reservoirs reflected the combination of wellbore data and geological understanding， as well as the integration of rock physics and logging models， and they demonstrated the ability of logging to serve geology and reservoirs and achieved good application results. In the future， the remaining resources will mainly be distributed in hidden oil and gas reservoirs and deep layers. In order to meet the needs of exploration and development， it is necessary to strengthen the analysis of experimental data， gas logging， and testing production data， combine logging evaluation and geology， intensify the application of new logging technologies such as logging while drilling， imaging， and nuclear magnetic resonance， carry out comprehensive research and evaluation， and expand the evaluation and prediction of production capacity of oil layers from the perspective of evaluation objectives. Moreover， it is necessary to fully rely on expert experience to select samples and deepen the application of big data/artificial intelligence on the basis of conventional technologies， which will definitely achieve good results.

A torsional strength model for prestressed concrete beams was proposed considering the initial crack angle, principal stress angle, and longitudinal strain, which are affected by the axial stress induced by the effective prestress. The use of the torsional effective thickness was also proposed to calculate the torsional strength of prestressed concrete beams by considering the effect of prestress. The shear element in the torsional member was simplified under the assumption that the principal tensile stress and principal compressive strain were negligible in the ultimate state. The torsional strength was determined when the principal compressive stress or shear stress at the crack surface in the shear element reached the failure criterion according to the multipotential capacity model, which considers concrete crushing and aggregate interlocking as the main resistances to the applied load. The proposed strength model was verified using test specimens collected from existing experimental studies. The proposed model accurately evaluated the torsional strength of prestressed concrete beam specimens, regardless of the key variables of the prestressed concrete specimens, where the mean value of the tested results to the calculated torsional strengths was 1.123, and the corresponding coefficient of variation was 17.7% for 104 prestressed concrete beam specimens, while the ACI 318-19 torsional design method gave the mean and coefficient of variation of 0.880 and 24.3%, respectively.

The methods are considered for determining the effective thickness of the hardened layer of metal parts listed in the standards STB 2307-2013 and STB ISO 18203-2019. The ambiguity of interpretation of the concept of effective thickness hэф of the hardened layer up to the half-transition zone is established for control of gears after the chemical heat treatment: carburizing and hardening. In practice, hэф is determined by the Vickers hardness distribution under the relevant load. In accordance with the standard ASTM E140-07, the Vickers hardness value of 50 HRC represents the Vickers hardness of 513 HV for non-austenitic structural steels when tested at 294.2 N. When testing Vickers hardness at lower loads, conversion tables or dependencies must be used. It has been shown that such measurements are more inaccurate at lower loads. To eliminate errors and increase accuracy of determining hэф of diffusion thickness of gear wheels after chemical-hardening, techniques are compared to determine hэф three: metallographic, mechanical and chemical. The Vickers hardness values determined during tests of structural non-austenitic steels with different loads correspond to the hardness value of 50 HRC. The values obtained can be applied to determine hэф of diffusion layers of surface-hardened parts corresponding to the half-transition zone.

The salt gradient solar pond (SGSP) is a renewable energy system that absorbs solar irradiation and keeps it as heat. The application of the SGSP in the cold seasons is limited. To keep the temperature of the SGSP in cold seasons, the heat extraction rate should be reduced or the Phase Change Material (PCM) is employed. The present study investigates the impact of the PCM with a melting temperature of 56 °C on the efficiency and applicability of the SGSP. The one-dimensional model of the SGSP including the heat and mass transfer equations are modelled using the finite volume method. The results showed that the latent heat emitted from the PCM helps maintain the temperature of the LCZ layer at the melting temperature of the PCM and enhances the efficiency of SGSP during the cold seasons. The effective thickness of the PCM is investigated and showed that it depends on the heat extraction rate. Using the effective PCM thickness, the average solar pond efficiencies increase to 11.5 and 13.8 for heat extraction rates of 21 W/m2 and 25 W/m2, using a PCM thickness of 0.4 m and 0.8 m, respectively.

Periodic radiation monitoring of soils today is a priority task not only for Belarus, but also for Japan, suffered by Fukushima nuclear power plant accident. Use of portable and light spectrometers with ability to perform in situ measurements makes it possible to quickly estimate specific activity of measured radionuclides with required accuracy in particular soil site. Basic information of a gamma radiation source (radionuclides content, effective radius of measurement area and thickness of contaminated layer) can be obtained directly during measurement. The purpose of this research is to test the feasibility of using algorithms for determination of specific activity and thickness of contaminated layer under conditions of soil measurement with variable density parameters and radiocesium distribution in soil.Monte-Carlo simulating allowed to estimate the degree of deviation of the shape of simulated spectra obtained with the use of Monte-Carlo soil model with uniformly distributed radionuclide in it, and for the case when the radionuclide distribution by soil profile can be described by an exponential function. For these cases of natural distribution of radiocesium, the pulse-amplitude spectrum is formed by an effective thickness of the contaminated site, which contains more than 90 % of radionuclides.The developed Monte-Carlo model of a probe and contaminated soil site allows to estimate the effect of the variability of soil density on the total count rate of the pulse-amplitude spectrum. As a result of theoretical estimations, the relationship between the effective radius of contaminated site is determined as a function of soil density.Analysis of the influence of radial zones of the cylindrical gamma source on in situ gamma-spectrometer showed that the main contribution to the total count rate of the pulse-amplitude spectrum is made by the radial zone with radius of up to 40 cm from the center of the probe, regardless of the thickness of the contaminated layer in geometry «Probe is located on the soil surface». A small site facilitates the selection of measurement area of land with a sufficiently flat surface, which is desirable during surveying the territories, especially with complex terrain.

In this work, a biosensing method based on in situ, fast, and sensitive measurements of ellipsometric parameters (Ψ, ∆) is proposed. Bare silicon wafer substrate is functionalized and used to bind biomolecules in the solution. Coupled with a 45° dual-drive symmetric photoelastic modulator-based ellipsometry, the parameters Ψ and ∆ of biolayer arising due to biomolecular interactions are determined directly, and the refractive index (RI) of the solution and the effective thickness and surface mass density of the biolayer for various interaction time can be further monitored simultaneously. To illustrate the performance of the biosensing method, immunosensing for immunoglobulin G (IgG) was taken as a case study. The experiment results show that the biosensor response of the limit of detection for IgG is 15 ng/mL, and the data collection time is in milliseconds. Moreover, the method demonstrates a good specificity. Such technique is a promising candidate in developing a novel sensor which can realize fast and sensitive, label-free, easy operation, and cost-effective biosensing.

The effectiveness of polypropylene fibers as sorbents of oil-water emulsions was the object of the research in the present publication. Thus the sorption capacity of the synthetic material of the regional production with for emulsions of different concentration was investigated. Santrauka Straipsnyje nagrinėjama polipropileno pluošto naudojimo avarinionaftos išsiliejimo metu problema. Polipropileno pluoštasnaudojamas kaip naftą sugerianti medžiaga. Pateiktos skirtingostorio polipropileno pluošto išsiliejusios naftos sugeriamumosavybės. Raktiniai žodžiai: nafta, išsiliejimas, sorbentas, polipropileno pluoštas, sugeriamumas.

This paper presents the results of an investigation into the post-buckling behaviour and ultimate strength of imperfect pitted steel plates used in ship and other marine-related structures. A series of elastic-plastic large deflection finite element analyses is performed on pitted steel plates. The effects of pitting corrosion on one side of the plates are introduced into the finite element models. The effects on plate compressive strength as a result of parametric variation of the pitting corrosion geometry are evaluated. A proposal on the effective thickness is concluded in order to estimate the ultimate strength and explore the post-buckling behaviour of pitted steel plates under uniaxial compression.