The CSEM method, which is frequently used as a risk-reduction tool in hydrocarbon exploration, is finally moving to a new frontier: reservoir monitoring and surveillance. In the present work, we present a CSEM time-lapse interpretation workflow. One essential aspect of our workflow is the demonstration of the linear relationship between the anomalous transverse resistance, an attribute extracted from CSEM data inversion, and the SoPhiH attribute, which is estimated from fluid-flow simulators. Consequently, it is possible to reliably estimate SoPhiH maps from CSEM time-lapse surveys using such a relationship. We demonstrate our workflow’s effectiveness in the mature Marlim oilfield by simulating the CSEM time-lapse response after 30 and 40 years of seawater injection and detecting the remaining sweet spots in the reservoir. The Marlim reservoirs are analogous to several turbidite reservoirs worldwide, which can also be appraised with the proposed workflow. The prediction of SoPhiH maps... [more]

The use of phase change materials (PCM) for thermal energy storage (TES) is of great relevance, especially for the exploitation, in various ways, of the major ecological resource offered by solar energy. Unfortunately, the transition to the liquid state of PCM requires complex systems and limits their application. The goal of producing shape-stabilized phase change materials (SSPCM) is mainly pursued with the use of media capable of containing PCM during solid/liquid cycles. In this work, four cheap shape stabilizers were considered: sepiolite, diatomite, palygorskite and zeolite and two molten salts as PCM, for medium (MT) and high temperature (HT). The SSPCM, produced with an energy saving method, showed good stability and thermal storage performances. Diatomite reaches up to 400% wt. of encapsulated PCM, with a shape stabilization coefficient (SSc) of 97.7%. Zeolite exhibits a SSc of 87.3% with 348% wt. of HT-PCM. Sepiolite contains 330% wt. of MT-PCM with an SSc of 82.7. Therefore,... [more]

The paper examined Ti3C2Tx MXene (T—OH, Cl or F), which is prepared by etching a layered ternary carbide Ti3AlC2 (312 MAX-phase) precursor and deposited on a polycaprolactone (PCL) electrospun membrane (MXene-PCL nanocomposite). X-ray Diffraction analysis (XRD) and Scanning Electron Microscopy (SEM) indicates that the obtained material is pure Ti3C2 MXene. SEM of the PCL-MXene composite demonstrate random Ti3C2 distribution over the nanoporous membrane. Results of capacitance, inductance, and phase shift angle studies of the MXene-PCL nanocomposite are presented. It was found that the frequency dependence of the capacitance exhibited a clear sharp minima in the frequency range of 50 Hz to over 104 Hz. The frequency dependence of the inductance shows sharp maxima, the position of which exactly coincides with the position of the minima for the capacitance, which indicates the occurrence of parallel resonances. Current conduction occurs by electron tunneling between nanoparticles. In the... [more]

This paper presents an experimental investigation of the hygrothermal and mechanical properties of innovative mortar mixtures reinforced with natural fibers. Fibers extracted from palm stems (PS) and hemp (HF) were evaluated at different percentages. Scanning electron microscope (SEM) observations showed that the PS fibers have rough surfaces and very complex microstructures. Prior to their incorporation into the mortar, the fibers were subjected to different treatments to reduce their hydrophilic character. The employed treatments showed good efficiency in reducing the water absorption of both PS and HF fiber types. Furthermore, the mortar mixtures incorporating these fibers exhibited low thermal conductivity and excellent moisture buffering capacity. Indeed, the moisture buffer value (MBV) of the investigated mixtures ranged between 2.7 [g/(%HR·m2)] and 3.1 [g/(%HR·m2)], hence providing them excellent moisture regulator character. As expected, the fiber mortar mixtures showed very hi... [more]

Phase change heat storage material is a preferred material in solar building heating or off-peak electric-heat storage heating technology and is the research focus. A compact phase change thermal storage device has been designed and experimentally studied for improving heating system load in this work. A new type, magnesium nitrate hexahydrate-based phase change material has been studied to improve the cooling degree and crystallization difficulty. The focus of this study is on the heat charging and discharging characteristics of this new phase change material. The heat storage device has two groups of coils, the inner side which carries water and the outer side which is the phase change material. A testing system was built up to value the thermal cycling performance of the heat storage device. The measurement data include phase change material temperature field, water inlet and water outlet mean temperature, heat charging and heat discharging depth, and flow rates over the operating p... [more]

Shale oil and source rock samples of the Carboniferous Keluke Formation from well Chaiye 2 in the Delingha Depression were analyzed by gas chromatography−mass spectrometry. Source rocks were highly mature at the gas generation stage with vitrinite reflectance (Ro) of 1.45−1.88%. However, the oil produced from the shale reservoir was characterized by abundant biomarkers but low abundance of diamondoid hydrocarbons with estimated Ro of ca. 0.78%, indicating hydrocarbons were still at a relatively low thermal maturity level. As the crude oil was generated and accumulated autochthonously, preliminary results indicate that crude oil and source rocks witnessed differential thermal evolution and significant disparity of the current thermal maturity in the shale reservoir due to rapid tectonic subsidence and clay mineral catalysts that accelerated the thermal maturation process. Although tectonic uplifts occurred afterwards, the vitrinite recorded the highest maturity that source rocks have ev... [more]

The use of polymer composite materials in the aeronautics and automotive sectors has increased dramatically, and their fire behaviour has become a critical parameter in terms of fire safety. On this premise, it is critical to demonstrate that these composite materials constitute elements whose safety justifies a high level of confidence. This is based on their combustibility and the rate at which flammable and toxic gaseous species are emitted. Thus, strict fire safety regulations are enforced by the relevant authorities concerned because of their potential fire risk. This study analysed papers published between 1970 and 2021 that described the devices used to characterise the thermal behaviour of composite materials at various scales. The objective was to highlight the thermophysical phenomena, making it possible to accurately assess the flammability and thermal stability of polymer composite materials. The results of this research reveal that the small-scale facilities provide detail... [more]

Solar still, a small equipment using evaporation and condensation processes to get clean water, is expected to be widely used for sea/brackish water desalination, water purification, and wastewater treatment because of its convenient carrying, friendly environment, and low energy consumption. In recent years, considerable progress has been made in improving the productivity of solar still. This paper will reclassify the methods to improve the solar still by elevating the evaporation rate and condensation rate. The main methods increasing evaporation rate are as follows: (i) adding heat storage materials; (ii) using nanoparticles; (iii) changing structure of the absorption plate; and (iv) using photothermal materials. The primary methods increasing the condensation rate are as follows: (i) cooling the condensing surface; (ii) increasing the condensation area; (iii) changing the wettability of the condensing surface; and (iv) using a separate condenser. The advantages and disadvantages o... [more]

Wax precipitation and deposition are serious flow assurance problems. Wax precipitation is investigated simultaneously using centrifugation and high-temperature gas chromatography (C-HTGC) to obtain the amount and component distribution of precipitated wax in artificial waxy oil and diesel at different temperatures. However, the conventional C-HTGC method gives upper measurements of the amount of precipitated wax, as it ignores wax dissolved in crude oil in the centrifugal cake. A modified C-HTGC method was developed to obtain the precipitated solid fraction of crude oil, based on the mass balances of the non-crystallized fraction of the centrifuged cake. The weight, percent and carbon number distribution of precipitated solid wax crystals at different temperatures of artificial oil and 0# diesel were obtained. It was found that wax precipitation characteristics are affected by many factors, including the carbon number distribution of the oil, the sensitivity of alkane crystallization... [more]

The process of underground coal mining fractures the overlying strata and may provide storage and transportation space for gas by changing the roof rock permeability, which is released by pressure after mining. This paper adopts the experimental method of physical similarity simulation and combines the fractal theory to study the permeability characteristics of the fracture network after mining, and it establishes the fractal permeability equation of pressure-relief gas. The results of the study show that the fracture opening shows a positive correlation with the overburden permeability, whereas the tortuosity of the fracture shows a negative correlation with the overburden permeability. The shape of the high permeability area in the fracture network is found to be similar to the hat-shaped elliptical parabolic zone. In the process of permeability evolution, the key layer structure of the overburden rock is considered as the main factor that affects the trend of change in permeability.... [more]

Under dehumidifying conditions, the condensed water will directly affect the heat transfer and resistance characteristics of a fin-and-tube heat exchanger. The geometrical form of condensed water on fin surfaces of three different fin materials (i.e., copper fin, aluminum fin, and aluminum fin with hydrophilic layer) in a fin-and-circular-tube heat exchanger was experimentally studied in this paper. The effect of the three different fin materials on heat transfer and friction performance of the heat exchanger was researched, too. The results show that the condensation state on the surface of copper fin and aluminum fin are dropwise condensation. The condensation state on the surface of the aluminum fin with the hydrophilic layer is film condensation. For the three different material fins, increasing the air velocity (ua,in) and relative humidity (RHin) of the inlet air can enhance the heat transfer of the heat exchanger. Friction factor (f) of the three different material fins decrease... [more]

Photo-excited charge carriers play a vital role in photocatalysts and photovoltaics, and their dynamic processes must be understood to improve their efficiencies by controlling them. The photo-excited charge carriers in photocatalytic materials are usually trapped to the defect states in the picosecond time range and are subject to recombination to the nanosecond to microsecond order. When photo-excited charge carrier dynamics are observed via refractive index changes, especially in particulate photocatalytic materials, another response between the trapping and recombination phases is often observed. This response has always provided the gradual increase of the refractive index changes in the nanosecond order, and we propose that the shallowly trapped charge carriers could still diffuse and be trapped to other states during this process. We examined various photocatalytic materials such as TiO2, SrTiO3, hematite, BiVO4, and methylammonium lead iodide for similar rising responses. Based... [more]

Hydrocarbon reservoirs can be subjected to temperature changes due to different processes during production. Heat injection has become an advantageous method to produce heavy oils in Canada and Venezuela because it increases oil recovery. The heat reduces oil viscosity and oil flows easily. Colombia has significant heavy oil reserves in unconsolidated silty sandstones. It is important to understand the mechanical behavior of these reservoirs in thermal recovery conditions (temperature and effective stress). The reconstituted samples from a Colombian heavy oil outcrop were evaluated using a high-temperature and high-pressure triaxial cell. Twelve isotropically consolidated drained triaxial tests were conducted at three different effective stresses (0.4, 4.0, and 8.2 MPa) and a temperature range from 50 to 230 °C to represent the initial and thermal recovery conditions, and obtain parameters, such as Young’s and Bulk moduli, internal friction angle, and cohesion. The samples at higher co... [more]

Boron-based materials have been widely studied for hydrogen storage applications. Examples of these compounds are borohydrides and boranes. However, all of these present some disadvantages that have hindered their potential application as hydrogen storage materials in the solid-state. Thus, different strategies have been developed to improve the dehydrogenation properties of these materials. The purpose of this review is to provide an overview of recent advances (for the period 2015−2021) in the destabilization strategies that have been considered for selected boron-based compounds. With this aim, we selected seven of the most investigated boron-based compounds for hydrogen storage applications: lithium borohydride, sodium borohydride, magnesium borohydride, calcium borohydride, ammonia borane, hydrazine borane and hydrazine bisborane. The destabilization strategies include the use of additives, the chemical modification and the nanosizing of these compounds. These approaches were anal... [more]

In this article, both numerical and experimental investigations were carried out on the durability of hemp concrete. For this, an accelerated aging process was performed using cycles of immersion, freezing and drying. Then, an experimental campaign was enabled to determine heat and mass transfer properties, as well as the microstructure for both aged and reference materials. Observations using a digital microscope showed the appearance of cracks at the interfaces and an increase of the porosity of about 6%. These microstructural modifications imply a non-negligible evolution of heat and mass transfer properties. Thus, a numerical model for the prediction of heat and mass transfer was developed. The prediction of physical phenomena was computed using both aged and reference material properties. It highlights the aging effects on the behaviour of the hemp concrete. The numerical simulation results showed significant discrepancies between the predicted relative humidity values for the two... [more]

The introduction of the fifth generation wireless systems caused social emotions regarding the impact of electromagnetic waves on people. Many people who consider themselves to be particularly sensitive to radiation make metal foil head covers (so called “tinfoil hats”) to shield their body from radiation. The aim of this paper is to show how effective the “tinfoil hat” really is when applied to base station radiation in a fifth generation telecommunication system. It presents the results of investigation on effectiveness of these protections in terms of their shielding properties at the frequencies used in fifth generation wireless systems. The research was carried out based on computer simulations. Remcom XFdtd software (software: XFdtd version 7.8.1 manufacturer: Remcom, 315 South Allen Street, Suite 416 State College, PA, USA) utilizing a finite difference time domain method and a numerical model of the head was applied to obtain the data on shielding properties of conductive head... [more]

The article presents the research made on the effects of methods of pressure-thermal agglomeration of corn bran, as well as the influence of processing parameters on selected physicochemical properties and biogas efficiency. Corn bran moistened to four levels of moisture content was used for the tests: 20%, 25%, 30% and 35% of dry matter. The pressure-thermal treatment was carried out with the use of a Brikol SJ25 pellet maker and a TS-45 single-screw extruder. In the tests of the extrusion-cooking process, three rotational speeds of the extruder screw were applied: 70, 90 and 110 rpm. The following characteristics were examined: efficiency of the extrusion-cooking and pelleting process, as well as the energy consumption. The water absorption index (WAI), the water solubility index (WSI), bulk density, kinetic strength, structure analysis by the ART/FTIR method, energy potential and the efficiency of cumulated biogas and cumulated methane per dry mass, as well as fresh mass and fresh o... [more]

On 2 October 2003 in Saint-Romain-en-Jarez (France) a fire in a farm building triggered an explosion in which 26 people were injured. Police investigation, based solely on an analysis of the effects and on general engineering knowledge, showed that the explosion was caused by an uncontrollably generated mixture of ammonium nitrate (AN) and molten plastic crates which formed an explosive mixture similar to ammonium nitrate fuel oil (ANFO). This is the only commonly known example of an ammonium nitrate blast taking place at its end user destination. Is such an explanation of the incident plausible and could a similar blast possibly happen anywhere else? The experimental results support this thesis of French investigators but raise further doubts. Laboratory reconstruction of the self-acting process of generating the explosive material confirmed the investigators’ report. However, other materials at the incident site could have influenced the final outcome too. The lab-recreated explosion... [more]

Passivhaus EnerPHit is a rigorous retrofit energy standard for buildings, based on high thermal insulation and airtightness levels, which aims to significantly reduce building energy consumption during operation. However, extra retrofit materials are required to achieve this standard, which raises a contradiction between how to balance the environmental impacts of the retrofitting material inputs and extremely low energy consumption after retrofit. This motivated the analysis in this paper, which aimed to evaluate the possibilities of reducing the required retrofitting material inputs when trying to achieve the EnerPHit energy standard using a typical suburban dwelling in China’s hot summer−cold winter climate region as a case study. Firstly, how the insulation performance of each envelope component affected the building’s energy consumption was analysed. Based on this, sensitivity simulations of combinations of different insulation levels with different fabric components were investig... [more]

The calorific value of household refuse (HR) is greatly improved after classification, which includes the implementation of sufficient pyrolysis conditions. Therefore, a better pyrolysis effect can be achieved by co-pyrolysis with industrial solid waste (ISW) with high calorific value. In this work, HR and ISW were used as raw materials for co-pyrolysis experiments. The influence on the distribution of three-phase products after co-pyrolysis, the concentration of heavy metals and dioxins in the flue gas, and the distribution of PCDD/Fs isomers were studied. The results showed that, at a temperature of 600 °C and H/C = 1.3, of the formed material, the quantity of pyrolysis gas was approximately 27 wt.%, and the quantity of pyrolysis oil was approximately 40.75 wt.%, which mainly contained alkanes, olefins, and aromatic hydrocarbons. When S/C = 0.008, pyrolysis gas accounted for 25.95 wt.% of the formed material, and pyrolysis oil for 41.95 wt.% of the formed material. The ignition loss... [more]

To obtain the knowledge that contributes to the safer operation of nuclear power plants and their prompt recovery and termination in the event of an accident, soft epoxy resins with rubber-based additives—used as insulators and airtight sealants in electrical penetrations in nuclear power plants—were aged under several simulated severe accident environments with different conditions of heat, gamma rays, and exposure to superheated steam containing no oxygen. Then, changes in structural, dynamic mechanical, mechanical, and dielectric properties were examined. It has been found that this resin becomes hard as a result of cross-linking if aged by irradiation with gamma rays. Since the cross-linking slows down the molecular motions, the glass transition temperature increases, whereas the dielectric permittivity and the dielectric loss factor decrease unless the steam penetrates the sample. Although the sample melts and disappears if directly exposed to superheated steam at 171 °C or 200 °C... [more]

Instability and high permeability are two of the problems facing tunnelling excavations in soils with high fines content. Among the different techniques used to improve these soils, the injection of cement grouts stands out. In this work, a grouting treatment is designed to ensure the stability of the ground during the construction of two tunnels linking two municipalities in the north of Spain in Biscay, and to reduce the inflow of water from the aquifer located in the vicinity of these tunnels. First of all, the rock mass is analysed and the material to be injected is selected on the basis of the authors’ experience as well as setting time and compressive strength. Subsequently, with a test device designed by the DinRock research group of the University of Oviedo, two types of laboratory tests are carried out in order to analyse the effect of fines migration and washing on the water flows and the effect of re-injections of grouts with different densities on the permeability value. Th... [more]

Nanoparticles are frequently used to enhance the thermal performance of numerous materials. This study has many practical applications for activities that have to minimize losses of energy due to several impacts. This study investigates the inclusion of ternary hybrid nanoparticles in a partially ionized hyperbolic tangent liquid passed over a stretched melting surface. The fluid motion equation is presented by considering the rotation effect. The thermal energy expression is derived by the contribution of Joule heat and viscous dissipation. Flow equations were modeled by using the concept of boundary layer theory, which occurs in the form of a coupled system of partial differential equations (PDEs). To reduce the complexity, the derived PDEs (partial differential equations) were transformed into a set of ordinary differential equations (ODEs) by engaging in similarity transformations. Afterwards, the converted ODEs were handled via a finite element procedure. The utilization and effec... [more]

This paper deals with pore-scale two-phase flow simulations in carbonate rock using the pore network method (PNM). This method was used to determine the rock and flow properties of three different rock samples, such as porosity, capillary pressure, absolute permeabilities, and oil−water relative permeabilities. The pore network method was further used to determine the properties of rock matrices, such as pore size distribution, topological structure, aspect ratio, pore throat shape factor, connected porosity, total porosity, and absolute permeability. The predicted simulation for the network-connected porosity, total porosity, and absolute permeability agree well with those measured experimentally when the image resolution is appropriate to resolve the relevant pore and throat sizes. This paper also explores the effect of the wettability and fraction of oil-wet pores on relative permeabilities, both in uniform and mixed wet systems.

The paper’s main purpose is to identify the differentiation and variation of electricity prices for households in EU countries. The specific objectives are to highlight the directions and differentiation of price changes in EU states, determine the degree of volatility (or stability) of electricity rates, and establish the correlation between electricity prices for household consumers and economic and energy parameters. All members of the European Union were chosen for this project as of 31 December 2019 (28 countries). The analyzed period covered the years 2008−2019. The source of collected information was the thematic literature review and the data from Eurostat. Descriptive, tabular and graphical methods, constant-based dynamics indicators, coefficient of variation, Kendall’s tau correlation coefficient, and Spearman’s rank correlation coefficient were used to analyze and present the materials. It was determined that higher electricity prices for households in the EU states were ass... [more]