Search

The sterile paper-plastic barrier system for packaging sterilized medical equipment is studied, the main factors affecting its breakdown are revealed, and the inhalation rate during the pressure sterilization is experimentally analyzed. The results offer a new window of opportunity for a stricter risk-analysis and a robust strategy for the pressure sterilization, and this paper can be served as an example of strict clinical applications. [ABSTRACT FROM AUTHOR]

The article discusses the establishment and evolution of the periodical, highlighting its role in promoting scientific research from Serbia and its commitment to quality and accessibility. Topics discussed include the historical context leading to the journal's foundation, the importance of international scientific collaboration, and the journal's dedication to open access and rigorous peer review.

In this study, three representative materials, wood, paper, and cloth from municipal solid waste, were studied separately in an atmospheric fluidized bed gasifier. The effects of different feedstock, equivalence ratio, gasification temperature, and calcium carbonate presence on syngas composition, the lower heating value, and carbon conversion efficiency were investigated at different operating temperatures (800-950 °C), and the equivalence ratio range from 0.2 and 0.5. As the equivalence ratio increased, the yields of syngas and its lower heating value decreased, whereas the CO2 yield and carbon conversion efficiency increased generally from wood gasification. Higher gasification temperature favored enhancing the CO and H2 yield and lowering the CO2 yield while the lower heating value and carbon conversion efficiency of syngas increased. Different variations of CO2 yield and the lower heating value of syngas were observed in different feedstock gasification. CaCO3 was more supportive for enhancing the yields of syngas components (H2, CO, and CH4) and lowering the CO2 yield, while a lower heating value of syngas was also increased from different feedstock gasification. However, an optimum temperature of 900 °C was the highest lower heating value of syngas, reaching 8000 kJ/Nm3 from wood gasification. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is to study a class of forest disease and insect infection models with time delay. The exact solutions are successfully obtained by using the homotopy perturbation method. [ABSTRACT FROM AUTHOR]

The article provides an overview of the International Conference on Mathematical Analysis, Applications and Computational Simulation (ICMAACS) and the awards presented at the conference. It mentions the Qin-Jiu-Shao Prize, which recognizes mathematicians who have made significant contributions to the field, and the Yang-Hui Award, which honors mathematicians for their internationally outstanding works. The ICMAACS Best Paper Presentation Award is also discussed, which is given to mathematicians and scientists who present their research at the conference. The document serves as an introduction to a scientific paper published in the journal THERMAL SCIENCE by the Vinča Institute of Nuclear Sciences in Belgrade, Serbia. It includes references to a mathematics encyclopedia and various web links related to the ICMAACS conference. The paper is available as an open access article under the CC BY-NC-ND 4.0 terms and conditions. [Extracted from the article]

In this paper, the reservoir brittleness index is determined by mineral composition and content ratio of shale reservoir, and the cementation degree of rock in different reservoirs is predicted based on spontaneous potential and natural gamma logging, and combined with the fracture toughness characteristics of rock mechanics, a new evaluation and prediction method for fracturing ability of shale reservoir is established, which integrates rock mineral composition, cementation degree and fracture toughness of rock. This model can be used to obtain quantitative characterization of fracturing ability in laboratory and field through laboratory test or field logging data. The fracability model established in this paper has been applied and analyzed in typical shale Wells and the evaluation results are consistent with the productivity monitoring data after fracturing, which verifies the accuracy of the model established in this paper. [ABSTRACT FROM AUTHOR]

This study conducted simulations to investigate the heat transfer dynamics of supercritical CO2 as a thermal carrier within oil shale formations. The paper aimed to elucidate the impact of formation physical properties on the pyrolysis efficiency of oil shale. The findings from the simulations indicate that porosity minimally affects the thermal sweep but is directly correlated with the heating pore area. Meanwhile, permeability significantly influences both porosity and the extent of pyrolysis sweep, suggesting the preferential selection of formations characterized by high initial porosity and permeability wherever feasible. [ABSTRACT FROM AUTHOR]

This paper proposes a logging data reconstruction method based on migration learning, which can reduce the dependence on labeled data and also help to improve the generalization ability of data-driven models. Reconstruction experiments are carried out using data from a block in the Junggar Basin of Xinjiang, and compared with the conventional data-driven long short-term memory network and recurrent neural network methods. The results show that the reconstruction results based on migration learning improve the accuracy by 21%, which is significantly better than the remaining two methods, and proves the feasibility of the method. [ABSTRACT FROM AUTHOR]

When a tunnel fire occurs, due to the difference of tunnel width and slope, both smoke countercurrent length distribution law and critical velocity will become different, and these two are very important parameters in tunnel longitudinal ventilation design. Therefore, for the design of smoke control and longitudinal ventilation of the tunnel, based on actual highway tunnel size, this paper established and ran a series of numerical simulations through FDS simulation software to study tunnel width and slope's effect on smoke countercurrent length and critical velocity. The results of this paper show that smoke countercurrent length decreases with tunnel slope's increase and increases with tunnel width's increase. Through dimensionless analysis, the prediction formulas of smoke countercurrent length and critical wind speed of large cross-section tunnel about tunnel width, slope and height are modified and established. The research conclusions can provide a theoretical basis for the longitudinal ventilation design, smoke prevention and exhaust measures and personnel evacuation in large cross-section tunnel fires. [ABSTRACT FROM AUTHOR]

A greater contribution energy production in the future should be expected from agricultural biomass, because current research indicates low utilization of agricultural biomass specifically in the direct combustion process. The paper presents an example of energy integration of the corn cob in the process of drying seed corn. The paper presents the efficient method of drying corn seed with one's own corn cob. The technological process of drying is presented through the technological process of operation of the corn seed dryer on the corn cob, the energy industrial plant of the dryer and the technological process of two-pass drying of the cob. The main characteristic of a given dryer is the process of two-pass drying of the cob, because the air passes through the cob layer twice and in that way energy is saved. The drying time on the presented dryer has been shortened from the usual time from 90-80 hours, i.e. by 11%. This increase in performance results in a 15% reduction in dryer operating costs. [ABSTRACT FROM AUTHOR]

The couple-Higgs equation is an important non-linear evolution equation in the field of physics. In this paper, the couple-Higgs equation is investigated by employing the tanh function method, and the new solitary wave solution is successfully constructed. Finally, the physical properties of this solitary wave solution are elaborated by plotting the 3-D graphs with proper parameters. [ABSTRACT FROM AUTHOR]

In this paper, the (2+1)-D cubic Klein-Gordon model is investigated, which is used to described the propagation of dislocation in crystals. A simple and efficient analytical technology is successfully employed to seek some new periodic and solitary wave solutions, which is called sine-cosine method. The physics properties of these obtained periodic and solitary wave solutions are illustrated by corresponding graphs. [ABSTRACT FROM AUTHOR]

Based on the single-layer potential theory, the Laplace equation can be converted into the problem of the first-kind boundary integral equation (BIE1st). The kernel of BIE1st is characterized by the logarithmic singularity. In this paper, we investigate the Nystrom method for solving the BIE1st. The numerical solutions possess high accuracy orders O(h³) and the combination of two kinds of Nystrom solutions has the same accuracy as the result with double grid. Furthermore, by the double power transformation, the proposed method can be used to deal with the problem on the non-smooth boundary and has the higher accuracy. The efficiency is illustrated by some examples. [ABSTRACT FROM AUTHOR]

In the paper, the 1-D wave equation and non-linear diffusion equation are considered and the approximate solutions are obtained by using the variational iteration method. The obtained results show that the proposed method is efficient and simple. [ABSTRACT FROM AUTHOR]

In this paper, a 3-D geomechanically model and a three-pressure profile along the wellbore trajectory were established to determine a reasonable drilling mud density window by establishing calculation methods and correlations between geomechanically parameters. On the basis of drilling mud density window, combined with the principle of ERW extended limit, the analysis models of the limits of density and flow rate of drilling mud were established, respectively, with the objective that the extension limit can fulfill the design depth of the wellbore. The results of the practical application illustrate the feasibility and correctness of this preferred model for the combination of drilling mud density and flow rate. [ABSTRACT FROM AUTHOR]

Microwave thermal shock is an optimized means of crushing rocks in engineering, in order to investigate the effect of microwave thermal shock on granite, this paper adopts microwave irradiation and SEM experiments to investigate the mechanical behavior and microstructural evolution law of granite, and the main conclusions are: With the increase of the duration of thermal shock, granite exhibits the law of linear increase, and the peak strength and elastic modulus show the trend of rising first and then decreasing; After thermal shock the acoustic emission signal of granite is linearly rising, while the internal shear cracks expand to form larger transgranular cracks, the results of the study have great significance for the future development of traditional mining technology. [ABSTRACT FROM AUTHOR]

In this study, a microstrip patch antenna design with a U-shaped patch and a paper-based substrate is presented. Metallic parts such as the patch, ground plane and microstrip line feed are designed in aluminum. Utilization of recyclable paper and aluminum yields a sustainable and environmentally friendly design. The dual-band antenna operates between 1.950-2.125 GHz and 2.650-2.825 GHz with a bandwidth of 0.175 GHz for both frequency ranges. It is suitable for multipoint distribution systems (2.076-2.111 GHz) and WiMAX application (2.700--2.800 GHz). Monopolar radiation patterns are obtained for the operation frequencies of both frequency ranges. Maximum gain values are 5.009 dBi and 5.413 dBi for the operation frequencies of multipoint distribution systems and WiMAX application, respectively. While the antenna can be used indoors and outdoors, radome design is not considered in the structure. No parasitic elements or slots are included in the antenna. All simulations are carried out by using ANSYS HFSS software package. [ABSTRACT FROM AUTHOR]

This paper considers a temperature-dependent thermal conductivity with memory property in a fractal space. The two-scale fractal derivative is adopted to model the temperature field in the spatial dimensions, and Caputo fractional derivative is used to describe its memory property. The variational iteration method is employed to solve the mixed model with great success. This paper offers a new window for studying intractable problems arising in porous media or unsmooth boundaries. [ABSTRACT FROM AUTHOR]

The paper aims at predicting the remaining useful life of highly reliable and long-life products with multiple and multi-stage characteristics in the degradation process. Considering the unit-to-unit variability among the product units, a new bivariate and two-phase Wiener process model with random effects is established. Schwarz Information Criterion is used to identify the change points of the degradation model, and the analytical expressions of life and remaining useful life are given by the concept of first hitting time. Furthermore, the appropriate Copula function is selected to describe the correlation between the two quality characteristics based on Akaike Information Criterion. A bivariate degradation model is established and the unknown parameters of the model are estimated by Markov Chain Monte Carlo method. Finally, the applicability and effectiveness of the proposed method are verified by the comparative analysis of turbine engine. [ABSTRACT FROM AUTHOR]

The challenge for a non-linear vibration system in a fractal space is more fractal dimensions than frequency-amplitude relationship, the system energy consumption depends upon its fractal property, so its best-case scenario is to establish a relationship among the fractal dimensions, frequency and amplitude. For this purpose, this paper studies a fractal-fractional vibration system of a mass attached to a stretched elastic wire in a fractal space, and its asymptotic periodic property is elucidated, the effect of the fractal dimensions on the vibration system is discussed. This paper offers a new road to fast and reliable analysis of fractal oscillators with high accuracy. [ABSTRACT FROM AUTHOR]

This paper studies a local fractional vibration system with a damped non-linear term to reveal its frequency property and its energy consumption. A modification of He's frequency formulation is recommended for this purpose. Some examples are given to illustrate the solving process and the reliability of the method. Additionally, the effect of the initial conditions on the vibrating properties is elucidated. This paper offers a new window for fast and effective insight into local fractional vibration systems. [ABSTRACT FROM AUTHOR]

In this paper, the permeability of sandstone, mudstone, gangue, and limestone under the condition of initial elastic deformation is obtained by transient method test. Mercury intrusion test is carried out on the four kinds of rock samples to obtain the initial permeability of the rock samples. The results show that the magnitude of permeability obtained by mercury intrusion test and transient method test is completely consistent. The measurement error is analyzed. The relative error of permeability in this paper is less than 6.0%. It can be showed that the use of transient method to measure the permeability of rock samples is reasonable and reliable. [ABSTRACT FROM AUTHOR]

Printed circuit heat exchanger is a micro-channel heat exchanger. Because of its high efficiency, high pressure and high temperature resistance, it has been widely used in photovoltaic power generation, nuclear energy and other fields. In particular, the research on the cross-section shape of heat exchanger channel has been widely concerned by researchers. In this paper, the printed circuit heat exchanger performance of semi-circular, square and trapezoidal channels with the same inlet and outlet area is compared under the pressure of 8 MPa. The heat transfer performance of the mass-flow rate in the range of 500-2000 kg/m2 under three cross-section shapes was investigated. The results show that the heat transfer effect of fluid in the trapezoidal channel is obviously better than the other two channels. This is mainly because the heat exchange contact area of cold and hot fluids in the trapezoidal channel is large, resulting in an increase in heat exchange between cold and hot fluids. When the inlet velocity is the same, the Reynolds number of the fluid in the trapezoidal channel is larger. The outlet temperature of the cold fluid in the trapezoidal channel is 7.9% higher than that in the semi-circular channel and 4.1% higher than that in the rectangular channel. The outlet temperature of the hot fluid in the trapezoidal channel is 6.28% lower than that in the semi-circular interface channel and 3.4% lower than that in the square channel. The trapezoidal channel printed circuit heat exchanger has better heat transfer effect and better heat transfer performance. [ABSTRACT FROM AUTHOR]

When a long-distance pipeline is shut down for maintenance due to corrosion and damage, the process of cooling down and waxing of crude oil in the pipeline is accompanied by complex phase change heat transfer, and it is important to obtain its temperature drop law to reasonably control the shutdown time and formulate restart plan. In this paper, the heat transfer problem of long-distance pipelines under operation and maintenance conditions was studied and refined. Considering the influence of flow and wax precipitation characteristics of crude oil on heat transfer, a multi-field coupled action model was established and analyzed by numerical simulation in combination with the wide-phase interface partitioning method of crude oil. The evolution of the original flow and temperature fields in the pipeline at typical locations of the maintenance pipeline was revealed, and the reasonable maintenance time was proposed based on the change of liquid phase rate. The research in this thesis refined the heat transfer mechanism of the solidified phase change of crude oil for long-distance pipeline shutdown. [ABSTRACT FROM AUTHOR]

The multi-parameter dependence of nanofluid viscosity and thermal conductivity on the flow and heat transmission properties of Al2O3-water nanofluid in micro-channels is investigated in this paper using a numerical simulation approach, exploring the effects of various parameters on flow and heat dissipation characteristics, such as flow velocity, pressure drop, temperature, and heat transfer coefficient, under different Reynolds numbers, etc. These parameters include the nanoparticle sphericity (0.5~1.0), volume fraction (0.6~6.0%), and temperature (290~370K) of the nanofluids, as well as the boundary parameter Reynolds number (200~1000). The results show that the multi-parameter dependence of nanofluid viscosity and thermal conductivity setting has a significant impact on the flow and heat dissipation characteristics of nanofluids, comparing analysis with the nanofluid viscosity and thermal conductivity only related to the volume fraction under the same condition. Under the combined action of sphericity, volume fraction, and temperature, increasing the sphericity increases the pressure drop and decreases the heat transfer coefficient. For example, at a Reynolds number of 1000, the maximum rates of change for pressure drop and heat transfer coefficient are 0.85 and 4.26, respectively. The nanofluid thermo-hydraulic performance is sensitive to temperature, volume fraction and sphericity in turn. Setting up viscosity and thermal conductivity equations with multiple parameter dependencies can provide more accurate results for the research of nanofluids, further deepening the application research of nanofluids. [ABSTRACT FROM AUTHOR]

This paper introduces non-linear approaches which include neural networks and ANFIS to identify and control heat transfer within a chamber. Initially, traditional linear models are obtained using transfer functions with delays through MATLAB identification tools. However, this traditional linear model failed to faithfully represent the system when the input was changed. This outcome was expected since linear models are reliable only within specific operational ranges. To create a novel model that is applicable across the entire state space, two alternative identification methods, utilizing neural networks and an adaptive neuro-fuzzy inference system were introduced. After testing them with input data not used during the training, the models were compared and all of them showed satisfying results. In the continuation of the research, control techniques based on these techniques were presented. After assigning an arbitrary temperature as a reference signal, inverse models were made and four controllers in direct inverse control scheme were compared: three feedforward neural networks with different numbers of neurons in the hidden layer and the adaptive neuro-fuzzy inference controller. The results and possible improvements are discussed in the conclusion. [ABSTRACT FROM AUTHOR]

The arc furnace is an important equipment in the production of manganese ferroalloys. In the smelting process, it produces high temperature flue gas above 700 K, which has high utilization value. During the pelleting process, moisture exists on the surface and inside of the pellets, which, if directly fed into the arc furnace, will lower the temperature of the furnace, affecting the production, and will also cause the pellets to burst, resulting in pressure fluctuations in the furnace and other hazards. The preheating shaft kiln reduces the moisture content of the pellet while preheating the pellet by utilizing high temperature flue gas. In this paper, through the establishment of porous media and shrinking core coupling mathematical model, to achieve the prediction of the heating and drying process of the pellets of various particle sizes, which is in good agreement with the production monitoring data. The results show that 9~11 mm pellets have the best preheating effect in terms of tail gas temperature, pellet temperature and preheating time. [ABSTRACT FROM AUTHOR]

Near-isothermal compression and expansion may be accomplished by injecting water droplets into the air during the process to increase the overall efficiency. However, little is known about the relationship between spray system parameters and compressed air energy storage (CAES). Furthermore, the experiments about CAES using spray-based heat transfer have not been investigated. The aim of this paper is to study the relationship between the performance of CAES and the spray system parameters by experimentally. The parameters including the spray closing time, the spray opening time, and the nozzle diameter are discussed. Results show that under the same operating conditions, the maximum air pressure in compression chamber reach to constant value when the spray closing time is 0.6 seconds, and spraying water mist within 0.6-1.2 seconds has no heat exchange effect on the air in the cylinder. During the compression process, the smaller the nozzle diameter is, the higher maximum pressure in compression chamber is. During the expansion process, if we ignore the energy consumption of spray system, the larger the nozzle diameter is, the more the expansion output is. Further investigation is recommended to optimize spray parameters based on different CAES systems. [ABSTRACT FROM AUTHOR]

Climate change and the increasing demand for energy become major issues in public discussions today. The Paris Agreement is one of the results of such public discussions that focuses on achieving the 2050 net zero emission target. Many energy agencies have created scenarios to achieve this target. In this regard, green hydrogen is expected to have a significant role in energy transition plan. For this reason, in recent years, research related to green hydrogen production using the water electrolysis method continues to develop. The paper aimed primarily to conduct an overview of alternative technologies that can be used in producing green hydrogen with the solar energy based low temperature water electrolysis method. Secondarily, it would present information about several solar energy-based electrolysis project plans and a summary of challenges and opportunities in the development of solar energy based low temperature water electrolyzers in the future. Furthermore, to achieve commercially viable green hydrogen production, it is important to find new ideas, potential solutions, and constructive recommendations as soon as possible for further development research. This paper expectedly would be able to help initiate the development of green hydrogen production research through water electrolysis technology that is efficient, cost effective economically, and environmentally friendly. [ABSTRACT FROM AUTHOR]

In this paper, we obtained a variable coefficient partial differential model that characterizes non-linear long waves with topography effects through the multi-scale perturbation expansion method, especially the new model caused by the variation of background shear flow over time. Next, the expansion Jacobian elliptic function method is used to provide an analytical solution for the model and analyze its wave characteristics. [ABSTRACT FROM AUTHOR]

In this paper, high temperature and high pressure corrosion test was used to simulate the corrosion process of multi-component thermal fluid (CO2/P2/H2O) on oil pipes (N80 steel), casings (J55, TP90H, P110 steel, and transportation pipe-lines (20# steel) in the process of CCUS technology application. The results show that during the entire corrosion process, the oil layer casing and surface casing are corroded most seriously in this environment, and the corrosion forms of these five steel materials in the CO2/O2 environment are uniform corrosion and local corrosion, and the corrosion products mainly consist of FeCO3, Fe2O3, Fe3O4, and FePPH crystals. These oxides form a double-layer film structure on the surface of the steel. The inner layer is denser and consists mostly of FeCO3 crystals, which has better protection against further corrosion of the internal steel. The outer layer is loose and porous, and its components are mostly FeCO3 crystals. Fe2O3, FePPH, Fe3O4, and FeCO3 crystals, have poor corrosion protection for internal steel. Due to the difference in corrosion products of the inner and outer film layers, relatively obvious local corrosion appeared on the surfaces of the five steel materials. [ABSTRACT FROM AUTHOR]

The micro-lattice phase change material is a new type of thermal control material that effectively integrates the metallic hollow micro-lattice and phase change material together and exploits their advantages on the heat transfer capability and the heat storage capacity. This paper proposes a model to predict the effective thermal conductivity of micro-lattice phase change materials considering the heat transferring between the two different phases. The Fourier's law and the modified volume calculation method were used to derive a new prediction model, and the prediction model was refined using the finite volume method. Testing and the finite element method were used to validate that the proposed prediction model is more accurate than traditional prediction models. At the same time, we also analyzed the influence of boundary effects and micro-structural parameters of the hollow micro-lattice on the effective thermal conductivity. [ABSTRACT FROM AUTHOR]

The hot spot temperature of oil-immersed transformer winding is an important factor affecting the aging of material insulation. In this paper, a magnetic field simulation model is established based on the electrical and structural parameters of the oil-immersed transformer, and the loss distribution characteristics of each wall of the transformer core, winding and fuel tank are accurately calculated by using the finite element simulation software. The simulation model of transformer fluid-thermal field is established, the simulation results of transformer thermal field are obtained, and the temperature distribution of oil-immersed transformer core and winding and the flow velocity around it are obtained. According to the simulation results of thermal field, the characteristic temperature measuring points with strong correlation between tank wall and winding temperature were determined. The inversion models of tank wall and winding hot spot temperature were established by using the support vector regression and back propagation neural network algorithm, respectively by central composite design method. The results show that the correlation coefficient of support vector regression algorithm in predicting winding hot spot temperature reaches 0.98, and the relative error between the model predicted value and the real value is less than 8%, which is more accurate than back propagation neural network. The aforementioned research provides the theoretical basis and technical support for real-time monitoring of oil-immersed transformer winding hot spot temperature. [ABSTRACT FROM AUTHOR]

As a core cooling device of reactor, a high temperature sodium heat pipe is designed in this paper which has a large aspect ratio of 126. The effects of heating mode and evaporation section length on its start-up are studied experimentally. The results show that the axial temperature uniformity of the heat pipe is better under variable power heating mode. As the evaporation cross-section length increases, thermal resistance decreases by 50%. Compared with heat pipes with low aspect ratio, heat pipes with large aspect ratio are more difficult to start up. Furthermore, numerical simulation is conducted on the designed sodium heat pipe to acquire the velocity and pressure distribution during steady-state operation. [ABSTRACT FROM AUTHOR]

Once there is a velocity gradient in a viscous fluid-flow, such as that across a shock wave, a viscous force and viscous energy loss exist inside the flow according to the Navier-Stokes equation, which may confuse the relative contribution of compressibility and viscosity. In this paper, a viscous shear vector is defined as the component of gradient vector of local velocity magnitude perpendicular to the velocity vector. Then, a local viscous energy flux vector is defined from the viscous shear vector after being multiplied by the viscosity and the velocity magnitude. The divergence of the viscous energy flux vector results in new expressions for viscous force and loss of viscous energy, in which all the square terms of derivative of velocity components correspond to irreversible energy loss. The rest part can be taken as a kind of mechanical energy transfer done by the viscous force, from which the viscous force components can be got based on the assumption that the viscous force vector is parallel to the velocity vector. The new equations are different from and more complex than those in the traditional Navier-Stokes equation. By the new theory, it is shown that there is no shear viscous force and shear viscous energy loss in the flow across a normal shock wave without velocity gradient perpendicular to the flow direction. [ABSTRACT FROM AUTHOR]

It is important to understand the vertical distribution characteristics of outdoor particulates concentration in typical seasons of winter and summer when people S living spaces are getting higher and higher above the ground. The different heights offloors (1st, 7th, 11th, 17th, and 27th) of a high-rise building in Xi'an at 8:00 a. m., 12:00 a. m., 3:00p. m., 6:00p. m., and 10:00p. m., respectively, were tested and analyzed in this paper. The results showed that the concentrations on non-working days were much lower than that on working days at different times and on different floors, and the concentrations of particulates were relatively low in summer. The particulates reached the highest at 12:00 a. m. in summer, with the average concentrations of PM10, PM2.5, and PM1.0 were 37.3 µg/m³, 31.6 µg/m³, and 29.4 µg/m³. While reached the highest at 3:00 p. m. in winter, with the average concentrations of PM10, PM2.5, and PM1.0 were 82.4 µg/m³, 64.8 µg/m³, and 57.7 µg/m³. The distribution of atmospheric environment in Xi'an is mainly dominated by small particulates. The particle sizes of low floors are mainly range from 1.0 µm to 2.5 µm, and the high floors are less than 1.0 µm. With the increase of floors and time, PM1.0/PM2.5 and PM2.5/PM10 show a trend of first decreasing and then increasing on working days, while PM1.0/PM2.5 and PM2.5/PM10 show a trend of first increasing, then decreasing and next increasing on non-working days. In addition, outdoor meteorological parameters will also have a certain impact on particulates concentration distribution. It provides reference values for controlling the particulates concentration in high-rise buildings. [ABSTRACT FROM AUTHOR]

Obtaining real natural gas hydrate pressure-retaining samples is challenging, necessitating the study of in-situ condition preserved coring (ICP-Coring) technology. In this paper, we simulated the in-situ formation of natural gas hydrate natural gas hydrate using a high pressure cooling method within a self-developed formation environment simulation chamber. Drilling experiments were conducted to examine the influence of drilling parameters on low disturbance drilling processes. Our findings indicate that the feed rate of the drill pipe primarily affects the force magnitude on the drill pipe, while the rotational speed of the drill pipe significantly impacts the stability of this force, with slightly higher rotational speeds resulting in less disturbance. [ABSTRACT FROM AUTHOR]

In this paper, CO2 fracturing experiments were carried out in a conglomerate to analyze the fracture morphology, and fracture surface characteristics, and discuss the fracture self-support mechanism. Results indicate that compared to supercritical CO2 (SC-CO2) fracturing, SC-CO2 shock fracturing can break through the limitations of in situ stress to develop more complex fractures. The SC-CO2 shock fracturing induced rougher fracture surfaces. As a direct result, rougher fractures with larger apertures have greater permeability and conductivity, approximately three times that of SC-CO2 fracturing. This is because, under the influence of impact, shear misalignment allows rough fracture surfaces to self-support and exfoliated particles to act as proppant, allowing SC-CO2 fracturing to form self-supported fractures with greater aperture and permeability. [ABSTRACT FROM AUTHOR]

In recent years, the theory of local fractional calculus has been widely used in the description of the fractional circuits. This paper presents a fractal RLC-parallel resonant circuit (FRLC-PRC) using the local fractional derivative (LFD). The FRLC-PRC is modeled by studying the non-differentiable (ND) lumped elements, then the ND conductance is obtained with the help of the local fractional Laplace transform (LFLT) and the ND parallel-resonant angular frequency (ND PRAF) is analyzed. It is found that the FRLC-PRC becomes the ordinary one when the fractional order S = 1. The obtained results show that the LFD is a powerful tool in the description of fractal circuit systems. [ABSTRACT FROM AUTHOR]

With the development of the oil industry, the accuracy of the conventional well structure design method will be lower and lower. In order to ensure the smooth progress of drilling construction, this paper proposes a risk assessment method for the formation be drilled based on the equivalent drilling fluid density matrix, which reduces the use of empirical coefficients in the well structure design and realizes the fine design of the well structure. [ABSTRACT FROM AUTHOR]

In order to select a better design trajectory, it needs to spend a lot of energy on parameter adjustment and calculation. Therefore, this paper establishes the intelligent optimization design model of horizontal well trajectory in with the target length and drilling string drag under rotary drilling conditions as the targets, and takes the target entry accuracy as the complex constraints. Meanwhile, multi-objective optimization algorithm and distributed calculation are used to realize the automatic optimization of the well trajectory. Under the given arithmetic conditions, compared with the original design trajectory, a horizontal well was designed with this method, the trajectory length is shortened by 92.1 m, and the maximum build-up rate is changed from 5.50° per 30 m to 4.97° per 30 m, reducing by 9.6%. Under the same BHA and boundary conditions, the drag becomes 232.42 kN, which is 6.8% lower than that before optimization. [ABSTRACT FROM AUTHOR]

In this paper, a novel box-type scheme with convergence order O(τ3-a + h²) is constructed for the fractional sub-diffusion equation with spatially variable coefficient under Neumann boundary conditions. Using L2 formula and the energy method, stability of the scheme are proved. A numerical example is carried out and the result meets with the theoretical analysis. [ABSTRACT FROM AUTHOR]

Under the goal of "achieving carbon peak by 2030 and carbon neutrality by 2060", how to select the type of fresh air system has become a key area of energy conservation. The method of outdoor design PM2.5 concentration is one of the important factors affecting the selection of fresh air filtration system. This paper first analyzed the PM2.5 concentration values of 31 cities in China from 2017 to 2020 based on mathematical induction, and next gave the recommended coefficient K under six urban economic regions methods in combination with the actual situation. Finally, the selection of air filters in five typical cities was taken as an example, the differences in recommended coefficient K and selection of outdoor design PM2.5 concentration under different recommended methods were compared and analyzed. The results showed that the recommended coefficient K under the six economic regions could meet the required K value needs of the region. The recommended coefficient K by the six economic regions methods based on per capita GDP is the best. Under that conditions, the recommended coefficient K of the five typical cities under strict and normal conditions differs from the average K values of the six methods by 0.06 and 0.04. This paper will provide a new method for the correct selection of outdoor design PM2.5 concentration in fresh air systems to achieve the dual carbon energy-saving goal. [ABSTRACT FROM AUTHOR]

The current flat-plate solar collectors perform best when their absorbers rotate around their axis. However, with their concentrators, reflectors, and tracking mechanisms, they take up a lot of space and are thus commercially speaking, not the best solutions. This paper proposes a novel solar collector design which employs the (relative) rotation of absorbers, but strives to combine the benefits of fixed and (absolute) tracking solar systems, i.e. volume occupancy from the former and thermal performance from the latter. The findings of our numerical analysis show that, the solar irradiance efficiency of this novel design is 20% higher than that of a fixed flat-plate collector during clear-sky days, and it is equally lower than that of an absolute tracking collector. This paper also introduces a new criterion for describing single-axis tracking solar collectors which should be included in the classifications of solar collectors. Finally, the article, which represents a continuation of our research in the field of solar energy utilization, can contribute to the future development of solar technologies and solve some of the current challenges. [ABSTRACT FROM AUTHOR]

A beam vibration originating in the beam porous structure or on a non-smooth boundary might make its vibrating energy concentrated on a single wave, leading to a solitary wave. This paper applies the variational approach to analysis of the soliton basic property, and the effect of the fractal dimensions on the solitary wave is elucidated. This paper is to draw attention the beam soliton property beyond its widely known resonance and periodic and chaotic properties. [ABSTRACT FROM AUTHOR]

In this paper, a generalized equal width wave equation involving space fractal derivatives and time Caputo fractional derivatives is studied and its approximate analytical solution is presented by the Adomian decomposition method. An example shows that the method is efficient to solve fractal non-linear partial differential equations. [ABSTRACT FROM AUTHOR]

The available potential energy of the diurnal internal tide in the Northwest Pacific ocean is studied by using short-term high-frequency mooring observations. The results show that in the upper layer of the ocean, its distribution is relatively chaotic, and it is greater between 1500-1600 m and 2500-3000 m in the middle layer of the ocean. At other depths, it is generally smaller, especially, at the bottom layer of the ocean, it is relatively small. This paper concludes that the marvel of measurement is the best science picks. [ABSTRACT FROM AUTHOR]

The stochastic P-bifurcation behavior of bi-stability in a generalized van der Pol oscillator with the fractional damping under colored noise and thermal excitation is investigated. Firstly, using the principle of minimal mean square error and linearization method, the non-linear stiffness terms can be equivalent to a linear stiffness which is a function of the system amplitude, and the original system is simplified to an equivalent integer order van der Pol system. Secondly, the system amplitude stationary probability density function is obtained by the stochastic averaging, and then based on the singularity theory, the critical parametric conditions for the system amplitude stochastic P-bifurcation are found. Finally, the types of the stationary probability density function of the system amplitude are qualitatively analyzed in each area divided by the transition set curves. The consistency between the analytical results and the numerical results acquired from Monte-Carlo simulation also testifies the theoretical analysis in this paper and the method used in this paper can directly guide the design of the fractional order controller to adjust the response of the system. [ABSTRACT FROM AUTHOR]

The micro-electro-mechanical system is widely used for energy harvesting and thermal wind sensor, its efficiency and reliability depend upon the pull-in instability. This paper studies a micro-electro-mechanical system using He-Liu [34] formulation for finding its frequency-amplitude relationship. The system periodic motion, pull-in instability and pseudo-periodic motion are discussed. This paper offers a new window for security monitoring of the system reliable operation. [ABSTRACT FROM AUTHOR]

The meteorological parameters, e.g., wind direction, wind speed and atmospheric stability, affect greatly the diffusion of pollution and radiological environmental impact assessment. Based on the hourly meteorological data obtained from an automatic monitoring station, the radiological impact indicated by the air concentration, individual dose and maximal individual effective dose were analyzed and compared between 2020 and 2021. The paper concluded that children are the main group to be the most easily infected, and the critical exposure path is internal exposure from inhalation. This paper offers a new window for timely decision-making for radiological safety under different climate conditions. [ABSTRACT FROM AUTHOR]