bluuebunny/crossref_metadata_2025 huggingface dataset:
The Optimization of LSTM Model by Wavelet Transform and Simulated Annealing Algorithm
Authors: Zheng Hao , Hu Jinyu , Ye Yingyan
Published: May 2024

The main objective of this paper is to study the integration of data processing methods and intelligent algorithms to optimize the results of LSTM prediction models. In this paper, continuous wavelet transform is used to clean and preprocess time series data and improve data quality. Wavelet reconstruction is used to restore the results. At the same time, the simulated annealing algorithm is introduced as an intelligent algorithm to search globally for the best solution to achieve the optimal prediction result. The application of this comprehensive approach can also improve the quality and precision of data analysis in various fields, such as the parameter estimation of pulse signals in physics. The core challenge of the research is to optimize the data prediction results, and for this purpose, a multi-level method of continuous wavelet transform, deep learning model (LSTM) and simulated annealing algorithm is adopted.
Application of a New Simulation Training System for Marine Oil Separators
Authors: Chen Yahui , Sun Jianbo , Ruan Zhang , Zuo Chunkuan
Published: May 2024

Aiming at the problems of the old models of fuel oil and lube oil separators in the existing domestic and foreign marine engine simulators, which can not carry out fault checking training and can not meet the requirements of the existing seafarers’ assessment standards, based on the composition and working principle of Alfa SU type separator, the mathematical models of fuel and Lube oil separator pipeline system, SU oil separator and EPC50 control unit are established by using modular modeling method By using VC + + , the calculation program and visual operation interface of the mathematical model are compiled, and the SU oil separator simulation training system is developed and applied to the evaluation training and assessment of seafarers organized by Liaoning Maritime Administration The simulation experiment and application practice show that the operating interface is the same as that of the real system, and the simulation model can accurately reflect the changing rule of the real system and reproduce the common fault phenomena, it meets the requirements of Seafarers’ evaluation criterion.
The Stability of Compressed Air Storage Underground Gas Storage Chamber and Steel Lining Structure Analysis
Authors: Ji Yang , Di ShengJie , Lu Xi , Liu Jing , Huang Peng
Published: May 2024

According to the address characteristics and structural characteristics of an underground artificial chamber gas storage, a structural model of an underground chamber including steel lining, flexible concrete, concrete lining, and surrounding rock is established, and two limit states of large slip and no contact between steel lining and flexible concrete are simulated respectively. The stability of the surrounding rock and lining structure are calculated and analyzed by using large finite element software FLAC3D and ANSYS respectively. The results show that the maximum deformation of the surrounding rock is 1.57cm, the maximum stress of steel lining is 262.08MPa, and the changes of plastic zone, displacement, and steel lining stress of surrounding rock can meet the design requirements of this project.
Study on Predicting Liquid Production Profile in Horizontal Wells Considering the Mechanism of Annular Flow Resistance and Water Control
Authors: Du Xinyu , Zhang Xianmin , Wang Tao , Zhu Xuchen , Xi Mengcheng , Yu Junzhi
Published: May 2024

The coated particle ICD water control technology has been widely used in horizontal well completion in offshore oil fields in recent years, but there is a lack of research on the simulation and prediction methods for liquid production profiles. By analyzing the dynamic inflow process of fluid, starting from the laws of momentum conservation and mass conservation, a coupled mathematical model of horizontal well reservoir wellbore pressure drop considering the mechanism of annular flow resistance was established, and solved through programming. Based on the actual well data of a certain block in an offshore oilfield, a horizontal well reservoir production model was established. The calculation results of the example show that the annular flow resistance and water control technology can effectively control the balanced liquid production of horizontal wells, thereby increasing the anhydrous oil recovery period and improving the oil recovery rate of the oilfield; The coupling model simulation and prediction method can fully reflect the mutual influence between the oil reservoir, wellbore annulus, ICD, and horizontal wellbore; The effective diameter of the ICD valve affects the changes in oil production and water content. The placement of the ICD well section has a significant effect on water control, and the compactness of the filled particles has a certain impact on pressure and water content changes.
Numerical Simulation of Ship-added Resistance Based on a Numerical Wave Tank
Authors: Han Shuai , Yang Lin , Zhu Qidan
Published: May 2024

The wave resistance increase of a ship during its actual voyage can affect its speed and safety. To design ships with excellent sailing performance, it is necessary to accurately predict the wave resistance increase of a ship in waves, as well as the motion response and wave resistance prediction of ships in waves, which involves complex hydrodynamic problems. This paper first establishes a physical model of the KCS vessel, then utilizes the numerical wave tank platform independently developed by our university. Based on viscous flow theory, it calculates the resistance of the KCS under calm water conditions. Using three-dimensional potential flow methods and spectral analysis, it computes the wave-induced resistance values for the KCS under six-degree sea states, analyzes the wave-induced resistance performance of the KCS, and ultimately, based on the calculation results of calm water resistance and wave-induced resistance combined with propeller efficiency parameters, calculates the effective power of the engine.
Numerical Calculation of 1P Aerodynamic Loads on Aviation Propellers
Authors: Tian Xiao , Yan Wenhui , Zhang Kun
Published: May 2024

To accurately predict the 1P aerodynamic loads of aviation propellers, this paper established a mathematical model of aviation propeller 1P aerodynamic loads based on the coupling method of blade element theory and momentum theory. Correction methods such as the Prandtl tip correction method and the propeller root correction method were implemented to further improve calculation accuracy. A 1P aerodynamic load calculation procedure was developed based on the mathematical model by using the Matlab software. 1P aerodynamic loads of a three-blade propeller were predicted for three different angles including 3 °, 9 °, and 12°. The numerical calculation results show that the calculated aerodynamic characteristic parameters of individual propeller blades obtained based on the propeller 1P aerodynamic load mathematical model deviate less than 6% from the CFD simulation results, and regular periodic pulsations are observed. The numerical calculations in this paper show that the propeller 1P aerodynamic load calculation procedure developed based on this model can accurately predict the propeller 1P aerodynamic load, which can provide some reference for the study of aviation propeller aerodynamic characteristics.
Effect of Water-added-mass on Modal Behavior of Shaft-line of Large Hydroelectric Generator Unit
Authors: Chen Weijiang , Huang Xingxing , Xie Jingpeng , Wang Zhengwei
Published: May 2024

The water-added-mass to a hydro turbine-shaft-line can significantly affect its modal behavior including the vibration modes and their natural frequencies. So it is of great significance to consider the effect of added water mass on the modal behavior of a hydro turbine to assure the safe and efficient operation of the hydro turbine-shaft-line system. In this investigation, the effect of water-added-mass on the shaft-line of one large prototype hydroelectric generator unit has been investigated in detail via the finite element tool. First, a CAD model of the shaft-line was created based on actual dimensions. Then a finite element model of the entire shaft-line was generated with high-quality hexahedral and tetrahedral cells. A first round of finite element simulation of the shaft-line in the air was performed without considering the effect of surrounding water, but the results were not realistic. On this basis, a finite element-based water-structure coupling simulation was carried out to analyze the effect of water-added-mass on the modal behavior of the shaft-line of the large hydroelectric generator unit. The result is more realistic to reality than that in the air. The results of this study show that when the water surrounding the turbine runner is added to the hydro-turbine shaft-line, it increases the overall mass of the shaft-line system, thereby reducing the natural frequencies of the system. The decrease in natural frequencies can cause the shaft-line to approach its critical speed during operation, vibrate at higher amplitudes than usual, and even lead to potential damage to the shaft-line system. According to the results calculated with the finite element water-structure coupling method, the countermeasures to improve the evaluation of the water-added-mass effect on the structural modal behavior of the shaft-line for the hydroelectric generator units have been provided. The conclusion can also apply to other hydraulic turbine and pump units.
Research of the Meshing Performance of New Concave-convex Ball Teeth
Authors: Shao Changjin , Yang Yousheng , Yang Wenchang
Published: May 2024

Aiming at the limitations of the existing hydraulic pumps, a new type of bidirectional water-hydraulic internal ball gear pump using concave-convex ball teeth meshing to transfer power is proposed. In this paper, the principle of internal gear pump is utilized to establish the model of internal ball gear pump, and its mechanical properties and dynamic meshing characteristics are numerically investigated by using the finite element method. The results show that (a) the concave-convex ball gears run smoothly without any interference, and (b) increasing the number of gear rows can effectively reduce the maximum stress and meshing impact under a given load and speed. This study provides a basis for the development of high-performance ball gear pumps.
Analysis of Seepage Field Characteristics of Water Diversion Power Generation System of Pumped Storage Power Station
Authors: Ji Yang , Shi Li , Cui Zhen , Lu Xi , Di ShengJie , Wang Dongtiao
Published: May 2024

Based on the diversion power generation system project of the Hami pumped storage Hydropower Station, the drainage substructure method is used to accurately simulate the drainage holes of the plant area, and the three-dimensional finite element model of the plant area including the main faults and reflecting the seepage characteristics of complex rock mass is established. Based on the inversion analysis of the natural seepage field, the distribution characteristics of the three-dimensional seepage field in the plant area were studied, and the rationality of the layout of the anti-seepage drainage system was evaluated. The results show that under the action of the anti-seepage drainage system, the groundwater level of the mountain is greatly reduced, and the descending funnel is formed in the three caverns, the seepage flow is controllable overall, and the permeability stability meets the engineering safety requirements.
Recent Advances in Water Treatment Membranes Based on Nanomaterials (A Review)
Authors: Farman Hala Y , Al-Anbari Riyad H , Haider Adawiya J
Published: May 2024

Nanomaterials have emerged as the next generation of materials for high-performance water treatment membranes, with the ability to address the global problem of pollution in water. Application of nanoparticles as membranes improves permeability feature for water, mechanical performance, efficiency of separation, and membrane fouling. As a result, the nanomaterials open up a new avenue for effectively selective membranes for purification of the water. This paper discusses the enhancements in membrane caused by the presence of various nanomaterials, such as nanoparticles (NPs), two-dimensional nano-materials (2D), nanofibers, nanosheets, and other nano-composite structure materials. Furthermore, the many uses of these membranes-based nanoparticles in treatment of water applications are emphasized. The goal is to show how important nanoparticles are in the membrane manufacturing in treatment of water. Nanomaterials and nanotechnology were discovered to have enormous promise for the progress of sustainable treatment of water and its wastes.
Geothermal energy concept applied to All-Air HVAC system
Authors: Darwiche Mohamad , Rabih Ali , Faraj Jalal , Keniar Mahdi , Akl Ibrahim , Ali Samer , Murr Rabih , Khaled Mahmoud
Published: May 2024

The novel method of combining geothermal energy with an all-air heating, ventilation, and air conditioning (HVAC) system is presented in this work. A building in Lebanon serves as the case study, which aims to determine the necessary mass flow rate for the conditioned space. Rather than permitting ambient air to enter the Air Handling Unit (AHU) directly, the plan calls for a 2-meter-deep geothermal duct to be buried. By adjusting the air temperature prior to it entering the AHU, this geothermal duct helps to improve the efficiency of the HVAC system and lowers the AHU’s yearly energy usage. Furthermore, the idea guarantees that there will always be 100% fresh air available, which means that the all-air HVAC system won’t need to recycle treated air from the conditioned space—also known as return air. According to the findings, the heat rate of the geothermal duct may reach 210 kW, which would result in a large decrease in CO2 emissions and cost savings for the HVAC system.
Study of Photon Emission at High Temperature of Quark Gluon Interaction
Authors: Daoud Aziz Raghad , Shweikh Ahmed M
Published: May 2024

In this paper, the photons emission rate from the interaction of quark with gluon is calculated and studied based on quantum chromodynamics theory. The photonic rate is calculated for u g→d g γ system at bremsstrahlung processes with Bag constant B1/4=0.235GeV and B1/4=0.275GeV, system temperature (325-625) MeV and the value of fugacity of quark λQ=0.9 and gluon λG=0.02 to emit photons with energy 0.5 ≤ Eγ ≤ 5GeV in hadronic phase. The effect of system temperature on the photons emission rate was studied and discussed, it was found that it increases with increases of system temperature and decreases of coupling strength due to the deconfinement phenomena furthermore the photonic yield at B1/4=0.235GeV is less than the photonic yield at B1/4=0.275GeV.
The Compressive Strength of Unsaturated polyester reinforced by natural and synthetic Calcium Carbonate
Authors: Jamal Mizban Rana , Hamdi Jassim Widad
Published: May 2024

A modifications on the ultimate compression strength of unsaturated polyester (UPE) carrying out, by adding nano Chicken eggshells fibers (E.S) as a natural source of calcium carbonate or synthetic nano calcium carbonate particles (CaCO3) in different weight percentages ranging from (1-5%). The ratio (1% eggshell fibers) and (3% CaCO3) are the best weight ratios that selected according to ultimate compressive strength of Unsaturated Polyester composites. Ultamite compressive strength was improved from (73.84 N/mm2) for UPE to (85.54 N/mm2) for (UPE/1% E.S) composite and to higher value (87.88 N/mm2) for (UPE/3%CaCO3) composite. The partictes with nano-sized of titanium dioxide (TiO2) was used to reinforce the two best composites, to get more improvement in there ultamite compressive strength to reach to (94.27 N/mm2) for (UPE/1%E.S) and to (100.18 N/mm2) for (UPE/3%CaCO3) composites.
A comparative study on the gas sensing performance of SnO2 and GO-SnO2 sensor devices.
Authors: Oppong Amoh Prince , Elwardany Ahmed , Fujii Manabu , Shokry Hassan
Published: May 2024

Using Modified Hummer’s technique, eco-friendly carbon derivative (GO) nanoparticles were obtained from polyethylene terephthalate (PET) precursor. Nanocomposite of GO-SnO2 and undoped SnO2 were synthesized using the coprecipitation method. The as-prepared nanoparticles were subjected to diverse analytical processes employing Transmission electron microscopy (TEM) to study the internal morphological properties of the nanoparticles. Energy dispersive X-ray spectroscopy (EDX) was used to examine elemental quantifications of the nanopowders. Fourier-transform infrared (FTIR) spectroscopy was used to analyze bond structures and functional groups. Dynamic responses of various gas sensor devices to 20 ppm concentrations of methane (CH4) and hydrogen (H2) were investigated as a function of time at room temperature. The GO-SnO2 nanocomposite sensing device demonstrated an ideal detection response with values of 5.00 and 5.08, corresponding to methane and hydrogen analyte gases. The doped SnO2 sensor device outperformed the pure SnO2, accounting for the GO-SnO2 > SnO2 order. Regarding the target gases, the synthesized nanocomposite demonstrated stability and selectivity in the following order of magnitude: H2 > CH4. The GO doping effect was found to have introduced surface defects, increased pores, and enabled more oxygen-active sites to be formed on the sensor device’s surface for dynamic gas sensing response, providing a comparatively enhanced sensor response.
Investigate various shielding parameters for (C18H20O8)x (ZrSiO4)100-x and (C18H20O8)x (BiClO)100-x in medical radiological applications
Authors: Abd-Noor Saddam Jamel , Mkhaiber Ahmed Fadhil
Published: May 2024

This study investigates some of shielding parameters of (C18H20O8)x (ZrSiO4)100-x and (C18H20O8)x (BiClO)100-x, x=(95,80,65,50)% wt coded as (S1,S2) for medical radiation application. We employed a theoretical model to calculate a mixture’s mass attenuation coefficients (MAC) during our investigation. The XCOM computer program was utilized for this purpose within the energy range of (0.356,0.364,0.44,0.662,0.739,0.834,0.846,1.17,1.238,1.274,1.33,1.368 and 2.754) MeV. The MAC values were used to compute several parameters, such as the linear attenuation coefficient LAC, half-value layer HVL, and effective atomic number Z
eff
. The study’s findings revealed a consistent decrease in the value of LAC as the energy increased for all the mixtures. The maximum value of LAC is 0.366 cm−1 in energy 0.356 MeV at x=50 for S2. The results show that adding BiClO to a matrix material can greatly improve its attenuation properties and be used to protect against medical radiation. The results show that the values of Z
eff
decreased with increasing energies, then stabilized and changed slightly at increasing energy. The lowest HVL values and the best for shielding were in group S2. The investigation also examined the association between the Z
eff
and the LAC at the value of x=50. The results show the correlation was positive and strong.
Calculating the Density Energy of Se100-XGeXand Se62Ge35X3Semiconductor Materials
Authors: Hasan Azzawi Jannah , Ayad Abdulmajeed Marwa , Mahdi Wadi Kassim , Ali Jasim Kareem , Shaban Auday H.
Published: May 2024

In this paper, chalcogenide glasses are studied using a range of experimental techniques for the purpose of understanding their electrical properties with the aim of providing new strategies for producing a new class of electronic devices made of advanced amorphous materials. The electrical properties of chalcogenide glass are very low cost to produce competitive devices; hence, a deeper understanding of their electrical transport properties may provide the necessary insight to enhance merit. For this purpose, the electrical properties studied by some researchers were relied upon, mathematical equations were performed and the program is designed to compute the energy state density in both extended and localized systems region of Se100-xGex with (x = 5, 25, 28, 30 and 38) and Se62Ge35X3glasses (where X is Sb, Sn, or Bi) in different concentrations. Characterizing the electrical properties of Se100-xGex and Se62Ge35X3glasses use to determine the density of energy states. The results of electrical measurements confirmed the presence of two mechanisms of electrical conduction: conduction in extended states at high temperatures and conduction in localized states at medium temperatures. Effective substitution results in a change in the local and extended state coefficients. This effect was measured as a function of concentration.
Ventilation Quality Assessment of Dual Courtyard Configuration
Authors: Mohamed Balah Eman , Shokry Hassan , Hagishima Aya , Mahmoud Hatem
Published: May 2024

Maintaining air quality within building spaces is a challenge under the increased pollutants resources. The optimization of the courtyard building layout toward natural ventilation has emerged as a critical factor in shaping air quality conditions. This study delves into the assessment of outdoor air quality infiltration within a dual courtyard typology characterized by varying proportions and orientations for both the connecting link and openings. To comprehensively analyse air quality within these integrated courtyards, a combination of on-site particle dispersion measurements and flow pattern simulations were employed. The outcomes of this investigation highlight the pronounced impact of atmospheric conditions, particularly wind direction, on the performance of courtyard configurations. The results revealed that dual courtyard provide an approach to address the geometric conflict between thermal comfort and air quality optimization. Even in circumstances with limited flow velocity, the direct connection between courtyards deepens the upward recirculating flow into the courtyard cavity at the activity level. The optimal air quality is attained by planning each courtyard’s upper-level intake and outflow openings, as it provides an evacuation flow out of court cavity and decline the PNC than outside surrounding conditions.
Effect of Sulfur on Characterization of AgInSe1.8S0.2 Thin Film and n-AgInSe1.8S0.2 / p-Si Solar Cell
Authors: Hussein Bushra H. , Hassun Hanan K. , Al-Maiyaly Bushra K.H. , Salman Ebtisam M-T. , Shaban Auday H. , Hady Mahdi Mohammad
Published: May 2024

Ternary Silver Indium selenide Sulfur AgInSe1.8S0.2 in pure form and with a 0.2 ratio of Sulfur were fabricated via thermal evaporation under vacuum 3*10-6 torr on glasses substrates with a thickness of (550) nm. These films were investigated to understand their structural, optical, and Hall Characteristics. X-ray diffraction analysis was employed to examine the impact of varying Sulfur ratios on the structural properties. The results revealed that the AgInSe1.8S0.2 thin films in their pure form and with a 0.2 Sulfur ratio, both at room temperature and after annealing at 500 K, exhibited a polycrystalline nature with a tetragonal structure and a predominant orientation along the (112) plane, indicating an enhanced degree of crystallinity. The Atomic Force Microscopy (AFM) was utilized to explore how Sulfur affects roughness of surfaces and sampls Grain Size. Furthermore, optical parameters, such as the optical gap and absorption coefficient, were calculated to assess the influence of Sulfur on the optical properties of the AgInSe1.8S0.2 thin films. The UV/Visible measurements indicated a reduction in the energy band gap to 1.78 eV for AgInSe1.8S0.2 at 500 K, making these films potentially suitable for photovoltaic applications. These thin films exhibited donor characteristics, with an increase in electron concentration observed with higher Sulfur content and annealing temperature.
A short recent review on geothermal energy piles
Authors: Dokmak Hanan , Faraj Khaireldin , Khaled Mahmoud , Faraj Jalal , Castelain Cathy
Published: May 2024

This manuscripts presents a short recent review of geothermal energy piles, emphasizing their problems, design elements, heat transfer fluids, and classification. Phase change materials (PCMs) are used as heat transfer fluids, and their beneficial effects on energy pile performance are highlighted. Design factors for the best energy pile performance are examined, including the usage of nanofluids and geometrical optimization. The analysis presented provides brief insightful information about the state of geothermal energy piles heaps now, laying the groundwork for future studies and advancements in this area.
Measuring the concentration of radon gas at the College of Dentistry- Al-Iraqia University using (CR-39) detector
Authors: Mudher Hassan Israa , Al-Sadoon Taghreed H. , Rehima Ali M. , Ahmed Ebrahiem Sameera , Jassem Kadhim Mothana
Published: May 2024

In this study, the concentration of radon gas was measured at the College of Dentistry-Al-Iraqia University using a nuclear pathway detector (CR-39). The detector was placed at a distance of 160 cm from the ground level. The detector was exposed to alpha fragments for 30 days. The results showed that the concentration of radon gas has Changed from one site to another. It ranged from the lowest (28.418 Bq/m3) to the highest (233.491 Bq/m3), with an average radon concentration equal to (90.279 Bq/m3). All results were within the permissible limit of a scientist except for one sample A2 in the chemistry laboratory, which was higher than the international permissible limits (200-300 Bq/m3) and recorded by the International Commission on Radiological Protection Statement on Radon.
Optical Characteristics of Rectangular Cross-Section Torus Waveguide
Authors: Kawthar H , Al-Majeed Abd , Hasan Alaa B
Published: May 2024

The rectangular cross-section waveguide made of PMMA is designed to efficiently transfer solar radiation from the source to the receiver, whether it be a (solar cell or a thermal reservoir) by the total internal reflection of the radiation within the waveguide. The waveguide is designed with a torus, like the letters U and S, which provides greater flexibility to reach previously inaccessible areas with traditional waveguide shapes. To design the waveguide, the simulation program (ANSYS Zemax OpticStudio 2022) uses the analysis tool in the program (detector viewer). The optical efficiency of the system was calculated by varying a set of optical parameters, such as the radius of curvature of the waveguide, the width of the entrance aperture, and the angle of rotation. The results showed that the designed (U) model offers more design flexibility than the (S) model, enabling greater geometric freedom in solar system design and providing greater diversity in design based on its intended purpose without significantly affecting the efficiency of the system.
Improving some of the physical properties of building blocks by adding porcelain in different proportions
Authors: Mohammed J. S. , Nsaif F. K. , Abbas Mustafa , Jasim Kareem A. , Shaban Auday H.
Published: May 2024

One innovative method that has been widely used over the past few decades is the production of heat-treated compressed earth bricks, which are low-cost and environmentally friendly. The aim of the current manuscript is to study the geotechnical properties of rammed earth bricks collected from four areas in Diyala Governorate, namely Baqubah, Al-Muradiyah, Khan Bani Saad, and Al-Rashidiyah, after placing the collected samples in special bags afterwards. The locations of each sample were determined using a GPS device. A mixture of soil samples taken from the study area was prepared to form a good soil mixture after grinding it well and sifting it with a sieve (2 mm). Then water was added in gradual proportions and it became a good mixture. It was dried and ground again after adding porcelain in different proportions (0, 5, 10.15%).). The soil mixture was mixed wet and then the samples were compressed under pressure (8 tons). Samples are placed in the oven at a temperature of 900°C for two hours to produce all models. All brick models produced are then dried naturally at room temperature for 28 days to undergo thermal insulation testing.
Impacts of wildfires on boreal forest ecosystem carbon dynamics from 1986 to 2020
Authors: Xu Yiming , Zhuang Qianlai , Zhao Bailu , Billmire Michael , Cook Christopher , Graham Jeremy , French Nancy HF , Prinn Ronald
Published: May 2024

Wildfires significantly change boreal forest ecosystem carbon balance through both direct combustion and post-fire carbon dynamics. Affected vegetation influences soil thermal regime and carbon cycling by impacting the surface energy balance of boreal forests. This study uses a process-based biogeochemistry model to quantify carbon budget of North American boreal forests during 1986–2020 based on satellite-derived burn severity data. During the study period, burn severity generally increases. Fires remove ecosystem carbon of 2.4 Pg C and reduce net ecosystem production (NEP) from 32.6 to 0.8 Tg C yr−1, making the forest ecosystems lose 3.5 Pg C, shifting a carbon sink to a source. The canopy’s cooling effect leads to lower soil temperature and lower net primary production due to lower nitrogen mineralization and uptake. Post-fire NEP decreases from 1.6 to 0.8 Tg C yr−1. This reduction accounts for 50% of the simulated NEP when the effects of fire-affected canopy are not considered. Our study highlights the importance of wildfires and their induced-canopy changes in soil thermal and ecosystem carbon dynamics of boreal forests.
A comprehensive review on flow field properties in polymer mixing processes: a focus on applications in energetic materials
Authors: Wang Jingcheng , Xie Zhongyuan , Liu Jing
Published: May 2024

The mixing process is a critical step in the production of energetic materials and has a profound impact on product performance. As modern formulations for energetic materials continue to advance, the needs placed on the mixing process have become increasingly complex. Understanding and mastering the properties of the mixing flow field are essential for achieving optimal mixing function, ensuring process safety, and optimizing the parameters of both the mixing process and equipment specifically for energetic materials. In this comprehensive review, we analyze the influence of flow field properties on the mixing process of energetic materials by examining the mixing mechanism of two types of flow within the flow field. Additionally, we provide evidence to support the advantages of elongational flow in achieving effective mixing. We also discuss the application of mixing flow field properties in the processing of energetic materials, including advancements in mixing equipment and methods designed to optimize flow fields. Finally, we address the current shortcomings in energetic material mixing and offer an outlook for future developments in this field.
Temperature dependence of phase stabilities of hexagonal hemicarbides from first principles
Authors: Deng Chao , Zhong Lisheng , Wang Xianhui , Yu Yutong , Peng Jianhong
Published: May 2024

Transition metal hemicarbides, specifically M2C (where M = V, Nb, Ta, Mo and W), have received considerable attention in the fields of catalysis and metallurgy. However, the determination of the exact phase of each compound can still be challenging due to the close energetic proximity of its various polymorphs. This study uses first-principles calculations to carefully consider the subtle differences between different polymorphs, with temperature as a key factor. It is found that the energies of each polymorph of M2C are close, but can be distinguished when temperature effects are considered. This means that temperature plays an important role in the polymorph transformations. In addition, these phases exhibit dynamic stability at both zero and finite temperatures, in part due to the particular ordering of C atom occupancy in the metal lattice interstices. The study can provide calculations of a range of properties that help to identify stable structures and deepen the understanding of these materials in terms of chemical bonding, structural changes, lattice thermal vibrations and molecular dynamics.
Prediction of flow stress in Mg-3Dy alloy based on constitutive equation and PSO-SVR model
Authors: Liu Yafei , Feng Yunduo , Liu Qiangbing , Luan Shiyu , Li Xiaowei , Liu Xiaoyu , Zhang Lei , Wang Jinhui
Published: May 2024

This study conducted hot compression experiments on as-cast Mg-3Dy alloy under deformation parameters of 380 °C–470 °C and 0.001–1 s−1. The microstructure of the alloy was observed using EBSD, and the flow stress of the Mg-3Dy alloy was predicted using the Arrhenius model and the particle swarm optimization-support vector regression (PSO-SVR) model. The organizational analysis results showed that the main recrystallization mechanism in the alloy is the discontinuous dynamic recrystallization (DDRX) mechanism. The generation of twins in the alloy was mostly the result of local stress action. The optimal processing window for this alloy was determined to be 380 °C–470 °C and 0.001–0.01 s−1 through the thermal processing map. The prediction accuracies of the Arrhenius model and PSO-SVR model were evaluated using the correlation coefficient R2 and mean squared error MSE. The results showed that the PSO-SVR model significantly outperforms the Arrhenius model in prediction accuracy, with R2 value of 0.99982 and MSE of 0.074.
Systematic analysis of the gallium ions and structure-directing agents in the preparation of NiW HDS catalysts over mixed oxides of Al2O3-TiO2
Authors: Guzmán-Cruz M A , Pacheco-Sosa J G , Morales de la Garza L , Gochi Bautista A I , Medina-Cervantes J A , Gutiérrez-López E D , Fuentes-Moyado S , Díaz de León J N
Published: May 2024

In this study, we prepared Al2O3-TiO2 (AT) mixed oxides to synthesize NiW catalysts for sulfur removal reactions. The AT support samples were prepared with various surfactants. Additionally, gallium atoms (2.4 wt%) were introduced as an additive to coat the outer surface layers of AT support that lacked Al3+ or Ti2+ cations. Characterization results showed substantial differences in textural properties, chemical composition, and surface acidity. The x-ray Photoelectron Spectroscopy (XPS) and High-Resolution Transmission Electron Microscopy (HR-TEM) results demonstrated that the NiW/AT-L-Ga sample has a better combination of dispersion, sulfidation, and promotion among materials. The sulfided NiW/AT-L-Ga catalyst had the highest catalytic activity. After incorporating Ga, XPS observed that the activity could be associated with an increase in the NiWS active phase; however, including a surfactant in the synthesis of the support allowed an increase in the amount of NiWS phase. The active phase was modeled considering the HR-TEM results for the slab length, revealing the atoms at the border susceptible to promotion.
Thermal damage to the skin from 8.2 and 95 GHz microwave exposures in swine
Authors: Parker J E , Butterworth J W , Rodriguez R A , Kowalczewski C J , Christy R J , Voorhees W B , Payne J A , Whitmore J N
Published: May 2024

A study of burn thresholds from superficially penetrating radio-frequency (RF) energy at 8.2 and 95 GHz for swine skin was conducted. The study determined the thresholds for superficial, partial-thickness, and full-thickness burn severities after 5 seconds of exposure at power densities of 4–30 W/cm2 and 2–15 W/cm2 at 8.2 and 95 GHz, respectively. There were significant differences in the burn thresholds at the different severities between the two frequencies due to the large difference in energy penetration depths. Biopsies were collected from each burn site at 1, 24, 72, and 168 hr post exposure. Each sample was assessed by a burn pathologist against 20 histological factors to characterize the damage resulting from these RF overexposures. A one-dimensional, layered digital phantom that utilized realistic values for dielectric and thermal properties was used to explain some observed thresholds. The results of the heating and cooling response of the animal model and histology scores of each exposure are provided to enhance future efforts at simulation of RF overexposures and to establish damage thresholds.
Benchmarking Bayesian quantum estimation
Authors: Cimini Valeria , Polino Emanuele , Valeri Mauro , Spagnolo Nicolò , Sciarrino Fabio
Published: May 2024

The quest for precision in parameter estimation is a fundamental task in different scientific areas. The relevance of this problem thus provided the motivation to develop methods for the application of quantum resources to estimation protocols. Within this context, Bayesian estimation offers a complete framework for optimal quantum metrology techniques, such as adaptive protocols. However, the use of the Bayesian approach requires extensive computational resources, especially in the multiparameter estimations that represent the typical operational scenario for quantum sensors. Hence, the requirement to characterize protocols implementing Bayesian estimations can become a significant challenge. This work focuses on the crucial task of robustly benchmarking the performances of these protocols in both single and multiple-parameter scenarios. By comparing different figures of merits, evidence is provided in favor of using the median of the quadratic error in the estimations in order to mitigate spurious effects due to the numerical discretization of the parameter space, the presence of limited data, and numerical instabilities. These results, providing a robust and reliable characterization of Bayesian protocols, find natural applications to practical problems within the quantum estimation framework.
‘Quantum technology will change my life.’ Citizens’ attitudes and knowledge of quantum science and technology
Authors: van de Merbel Anka , Peer Jasper , Willems Sanne J W , Cramer Julia
Published: May 2024

Technology experts, industry leaders, and policy makers expect that a revolution in quantum technology is imminent. From earlier emerging technologies such as nanotechnology, it has become clear that an early connection with the public is beneficial for the societal impact of the technology. However, little research has yet been done on public attitudes and knowledge of quantum science and technology. In this work, we quantitatively measure the attitude of N = 145 citizens of Leiden (NL) towards quantum science and technology and probe their knowledge on quantum concepts. Results indicate that these citizens have heard about ‘quantum’ through a wide variety of sources. They see quantum as globally important and admirable and most would like to learn more about quantum, but they do feel disconnected from developments in the field. Recommendations for the future include emphasizing any personal connections between citizens and quantum, adapting explanations to fit any level of education, and providing either reliable sources or a framework for critically evaluating quantum-related information.
Comparison of optical trapping wavelengths for nanoscopic diamonds containing nitrogen-vacancy centers
Authors: Roy Srestha , Ghosh Atanu , Lokesh Muruga , Nalupurackal Gokul , Chakraborty Snigdhadev , Goswami Jayesh , Bhallamudi Vidya P , Dhomkar Siddharth , Roy Basudev
Published: May 2024

In this article, we explore the effect of two different infrared (IR) laser wavelengths on the optical properties of trapped nano-diamonds containing high-density ensembles of nitrogen vacancy (NV) centers. We investigate 975 nm and 1064nm wavelengths for trapping lasers and find that NV photoluminescence quenching is more prominent for 1064nm illumination than for 975 nm illumination when simultaneously excited with a 532 nm laser. In order to understand the underlying mechanism, we develop a rate-equation-based model that takes into account various transition probabilities. The model suggests that the findings cannot be explained only by imposing modification of the NV charge-state ratio under varied illumination wavelengths, and, thus, we speculate that the effective ionization and recombination rates associated with NV charge states for the studied samples are highly wavelength-dependent in the probed regime. Importantly, the results demonstrate that 975 nm laser is desirable for optical trapping of NV-diamonds, especially for NV-based sensing applications.
Detection method for structural defects of U-shaped hanging ring for power fittings based on magnetic leakage principle
Authors: Bai Xin , Ji Hongling , Wang Leyu , Zhou Yang , Wu Jinnan , Jiang Yuan , Zhang Zhanlong
Published: May 2024

The U-shaped hanging ring of electric power fittings is usually installed outdoors and operates in harsh environments. Under the combined effect of the weight of the conductor and wind load, the bending part at the bottom of the U-shaped hanging ring often experiences wear and cracks due to friction contact, which can easily lead to accidents such as the detachment of transmission lines. Traditional methods for detecting structural defects in ferromagnetic materials, such as ultrasonic testing, eddy current testing, and manual testing, are affected by environmental factors, have a shallow measurement depth, and are difficult to quantify. In order to solve the above problems, this paper proposes a measurement method for detecting structural defects in the U-shaped hanging ring of electric power fittings based on the principle of magnetic leakage. The magnetic leakage signal characteristics of U-shaped hanging ring defects under different excitation structural parameters and different defect types are analyzed. The method of arranging magnetic leakage signal measurement points is studied. The detection of defect parameters is achieved based on the characteristic quantity of the magnetic leakage signal under different defect conditions. Finally, the method is analyzed and verified through examples. The results show that this method can achieve quantitative detection of defect parameters in the U-shaped hanging ring under uniform structural defect and crack structural defect, and has the advantages of high measurement accuracy and small error. The research results of this paper can provide a scientific theoretical basis for the inspection and replacement of transmission line fittings in engineering, which is of great engineering significance for ensuring the safe and stable operation of the power grid.
Cell type- and transcription-independent spatial proximity between enhancers and promoters
Authors: Mian Yasmine , Wang Li , Keikhosravi Adib , Guo Konnie , Misteli Tom , Arda H. Efsun , Finn Elizabeth H.
Published: May 2024

Cell type–specific enhancers are critically important for lineage specification. The mechanisms that determine cell-type specificity of enhancer activity, however, are not fully understood. Most current models for how enhancers function invoke physical proximity between enhancer elements and their target genes. Here, we use an imaging-based approach to examine the spatial relationship of cell type–specific enhancers and their target genes with single-cell resolution. Using high-throughput microscopy, we measure the spatial distance from target promoters to their cell type–specific active and inactive enhancers in individual pancreatic cells derived from distinct lineages. We find increased proximity of all promoter-enhancer pairs relative to non-enhancer pairs separated by similar genomic distances. Strikingly, spatial proximity between enhancers and target genes was unrelated to tissue-specific enhancer activity. Furthermore, promoter-enhancer proximity did not correlate with the expression status of target genes. Our results suggest that promoter-enhancer pairs exist in a distinctive chromatin environment but that genome folding is not a universal driver of cell-type specificity in enhancer function.
‘Kinning’ Education
Authors: Hebbar N. Nandini
Published: May 2024

This chapter uses the metaphorical and conceptual frames of genealogy to establish the local histories of engineering colleges. Historical shifts such as the mechanization of agriculture and the region’s participation in the global knitwear industry contributed to the prosperity and the necessary resources for investment in higher education. The chapter takes forward the argument that neoliberalism and privatization do not take place as a sweeping change, but move forward through the circulation of an ‘economy of affect’. In the case of Kongunadu, successful privatization has been achieved through the secularization of traditional patronage as philanthropy as well as efforts by various backward class groups to enter education in general, and engineering education in particular. This has also sealed a new form of industry in the form of ‘edupreneurship’.
Using Eye tracking to Examine Young Adults’ Visual Attention to E-cigarette Advertising Features and Associated Positive E-cigarette Perceptions
Authors: Chen-Sankey Julia , Weiger Caitlin , La Capria Kathryn
Published: May 2024

Background

Little is known about the influence of e-cigarette marketing features on the antecedents of e-cigarette use.

Purpose

Using an eye-tracking experiment, we examined visual attention to common features in e-cigarette ads and its associations with positive e-cigarette perceptions among young adults.

Methods

Young adults (ages 18–29) who smoke cigarettes (n = 40) or do not use tobacco (n = 71) viewed 30 e-cigarette ads on a computer screen. Eye-tracking technology measured dwell time (fixation duration) and entry time (time to first fixation) for 14 pre-defined ad features. Participants then completed a survey about perceptions of e-cigarettes shown in the ads. We used regression models to examine the associations between ad features and standardized attention metrics among all participants and by tobacco-use status and person-aggregated standardized attention for each ad feature and positive e-cigarette perceptions.

Results

Dwell time was the longest for smoker-targeted claims, positive experience claims, and price promotions. Entry time was the shortest for multiple flavor descriptions, nicotine warnings, and people. Those who do not use tobacco had a longer dwell time for minor sales restrictions and longer entry time for purchasing information than those who smoke. Longer dwell time for multiple flavor descriptions was associated with e-cigarette appeal. A shorter entry time for fruit flavor description was associated with positive e-cigarette-use expectancies.

Conclusions

Young adults allocated attention differently to various e-cigarette ad features, and such viewing patterns were largely similar by tobacco-use statuses. Multiple or fruit flavors may be the features that contribute to the positive influence of e-cigarette marketing among young adults.
Artificial intelligence–aided steatosis assessment in donor livers according to the Banff consensus recommendations
Authors: Jiao Jingjing , Tang Haiming , Sun Nanfei , Zhang Xuchen
Published: May 2024

Objectives

Severe macrovesicular steatosis in donor livers is associated with primary graft dysfunction. The Banff Working Group on Liver Allograft Pathology has proposed recommendations for steatosis assessment of donor liver biopsy specimens with a consensus for defining “large droplet fat” (LDF) and a 3-step algorithmic approach.

Methods

We retrieved slides and initial pathology reports from potential liver donor biopsy specimens from 2010 to 2021. Following the Banff approach, we reevaluated LDF steatosis and employed a computer-assisted manual quantification protocol and artificial intelligence (AI) model for analysis.

Results

In a total of 113 slides from 88 donors, no to mild (<33%) macrovesicular steatosis was reported in 88.5% (100/113) of slides; 8.8% (10/113) was reported as at least moderate steatosis (≥33%) initially. Subsequent pathology evaluation, following the Banff recommendation, revealed that all slides had LDF below 33%, a finding confirmed through computer-assisted manual quantification and an AI model. Correlation coefficients between pathologist and computer-assisted manual quantification, between computer-assisted manual quantification and the AI model, and between the AI model and pathologist were 0.94, 0.88, and 0.81, respectively (P < .0001 for all).

Conclusions

The 3-step approach proposed by the Banff Working Group on Liver Allograft Pathology may be followed when evaluating steatosis in donor livers. The AI model can provide a rapid and objective assessment of liver steatosis.