bluuebunny/crossref_metadata_2025 huggingface dataset:
Calculation of Evaporation Losses for Center Pivot Sprinkler Irrigation Systems Type (Lindsay) by Effect of Timer Percentage of Speed and the Increase of Sprayer Nozzles from Soil Surface
Authors: Al-Mehmdy Shuker M , Gar Laith F , Abood Mohammed A
Published: August 2023

The experiment was conducted during summer season (July, August, September) 2019 in some field in Anbar governorate, Saqlawiya city, Gisaba area to calculate water losses by evaporation through water depths by calculating the discharges that come from nozzles and water depths to collect in side cans while calculating uniformity coefficient above soil surface. The results showed that the increase of spray nozzles in soil surface at 1.0m gave the lowest depths from evaporated water by changing the timer speed percent; where it was 0.18mm 100% speed, while increased to 3.39mm at 20% speed compared 0.66mm at 100% speed till 5.91mm at 20% speed when expanding the sprayer nozzles to 1.50m from soil surface. The 100% speed gave low percentage of losses (1.79%) and the high percentage was obtained at 20% speed (33.70%) at 1.0m height, which is better that height of 1.50m in rationalizing water in order to irrigate new areas that water was not enough for. this is due to variation in the height of spray nozzles above the ground, as well as variations in temperature and wind speed steadfastly speed up the system.
The Water Footprint and Virtual Water and Their Effect on Food Security in Iraq
Authors: Al-Badri Basim H , Mohammad Mohammad Kh , Khalid Jehan O
Published: August 2023

The study aimed to explaining the concepts of water footprint and virtual water and how these two concepts could use to achieve water savings at the local level to meet the water supply deficit in Iraq, which is expected to increase in the coming years and influence of that on food security in Iraq by using these concepts when drawing production, irrigated and import plans in Iraq. The study aimed to studying the water footprint and virtual water and their impact on the foreign trade for wheat and rice crops during the period 2000-2022 and estimating the most important indicators of virtual water and the water footprint of the study crops due to the importance of these criteria in determining the amount of increase or decrease in the area of the studied crops, according to the foreign trade policy. This study was concluded that the average total water footprint of the wheat and rice crops during the study period is (20.27,13.89) billion m3 respectively, and the average percentage of dependence on external water resources for both crops are (20.49%,67.98%) respectively, and the average percentage of self-sufficiency in water resources are (79.51%,32.01%) respectively, and the average unit productivity of irrigation water for both crops is (0.19,0.10) kg/m3 respectively during 2000-2022.The average for the water needs of wheat and rice crops during the study period were (6.04,10.19) m3/kg respectively, the average amounts of water used in local production for both crops are (14.23,4.01) billion m3 respectively, the average amounts of virtual water imported for both crops are (6.19,10.03) billion m3 respectively, and the average value of the imported virtual water for both crops is (382,529) thousand dollars during the period 2000-2022. The study recommended to taking in account these concepts in plans of production and distributing irrigation water.
Irrigation with saline water for quinoa crop (Chenopodium quinoaWilld) depending on growth stages and its effect on plant yield and salt accumulation
Authors: Salim Saifuldeen A , Alalwany Abdulkarem A
Published: August 2023

The study aimed to determine the success of the use of saline water during certain stages of the growth of the quinoa ( Chenopodium quinoa Willd ) plant and to provide a portion of fresh water without affecting the yield significantly. A field experiment was carried out with a Randomized Complete Block Design, in which Euphrates River (fresh water) (R), and saline groundwater (S) were used, its electrical conductivity was 1.6 and 5.1 dSm−1 respectively.Growth stages were divided into four stages: germination and emergence -vegetative growth - flowering - yield formation. Five treatments were used for irrigation: treatment T1, irrigation with river water for the four stages (RRRR), treatment T2: irrigation with river water for the first and second stage, and saline water for the third and fourth stage (RRSS), and treatment T3: irrigation with river water for the first and third stage and saline water for the second and fourth stage (RSRS),while treatment T 4: irrigation with river water for the first stage and saline water for the other three stages (RSSS). and treatment T5: irrigation with saline water for all stages (SSSS). Plant growth and yield were followed, as well as the amount of salt accumulation in the soil before planting and after harvest.
Sustainability of Agricultural Productivity of Potato Crop in Desert Soils and Evaluation of Water Productivity Under Drip Irrigation System with Future Climate Changes
Authors: Salim Shatha , Ati Alaa S , Ali Alaa
Published: August 2023

A field experiment was conducted during the spring season 2020 in Karbala proving/ Al-Sharia Distrit, located at latitude N 32° 42' 13.8" and longitude E 43° 54' 36.6" and at an altitude of 27 m above sea level. The experiment included a study of two factors: the first, Irrigation Interval, three treatments were used: irrigation treatment every 2 days, Irrigation treatment every 4 days, and Irrigation treatment every 6 days. The second factor is the addition of soil conditioners, in which four treatments were used: the control treatment without any addition, the treatment of adding bio-organic fertilizers, the treatment of adding water-conserving technology (polymer), and the treatment of adding water-conserving technology + fertilizers Organic vitality. The experiment was designed according to the randomized complete block design (RCBD) with three replicates and under the split block design (split block design).It use the results of regional climate models to highlight how climate change affects the region through the AquaCrop model and repeat the same process for another regional climate model and another scenario to assess the impact using climate projections and analyzing the impact of climate change on water resources, the results were as follows: An increase in the amount of annual rainfall and monsoon rain during the two periods (2016-2035) and (2046-2065) under the RCP4.5 scenario, amounting to 17.00, 9.42, 11.91, and 9.06 mm. respectively compared to the base period (1985-2005) and its increase during the period (2016-2035) according to the RCP8.5 scenario amounted to 3.97 and 4.51 mm, with a slight decrease during the period (2046-2065) amounting to -3.78 and -2.57 mm, respectively, compared to base period. An increase in the maximum and minimum temperatures, according to the climate change scenario RCP4.5, amounted to 0.81, 0.75, 1.65, and 1.55°C, and the RCP8.5 scenario amounted to 1.1, 0.98, 2.33, and 2.14°C, as an average of the values of climate models. (EC-Earth, CNRM-CM5, GFDL-ESM2M) for the maximum and minimum temperatures, respectively, during the period (2016-2035) and (2046-2065), compared to the base periodd. There were no significant differences between the current productivity of the potato crop and the expected productivity using the AquaCrop model, so the value of R2 was 0.85 between the expected and measured data for productivity for twelve years under the surface drip irrigation system.The correlation coefficient (r) was 0.951, the root mean square error (RMSE) was 2.426, and the efficiency coefficient was 0.659 for the surface drip irrigation system.
Effect of Nanophosphorous and Arginine on the Wheat Triticum aestivum L. Under water Deficit Condition
Authors: Al-shaheen Mustafa R , Nayyef Yasir M , Sabry Nawfal A
Published: August 2023

To investigate the effects of Nanophosphorous and Arginine on wheat, a field experiment was conducted in one of the farmers’ fields in the east of Anbar, Iraq, in order to improve wheat drought tolerance. The plants were sprayed with Nano phosphorous, and Arginine was shown to have the highest rate of all the investigated features. The results demonstrated that the interaction between the study parameters was successful in increasing plant resistance to water deficiency.
Multivariate Statistical Methods Used in Determining the Hydrogeochemical Surfaces of Groundwater in Yusufiya District
Authors: Hussain Tariq A , Jumaah Ghufran F , Al Kindi Ghayda Y
Published: August 2023

For the importance of groundwater and being the second natural source of water after surface water, it is necessary to know the quality, features and hydrological surfaces of this water. For this reason, 15 wells were chosen in the Al Yusufiyah sub-district to study the quality of groundwater based on multivariate statistical methods as well as the Piper chart. These methods proved successful in characterizing the study of groundwater chemistry and can be relied upon for ground and surface water in other regions. The quality of the groundwater in Al Yousifiyah, according to Piper’s scheme, the alkalinity increases with the presence of sulfate and chloride, depending on the type of soil. From the analysis of the correlation matrix, the totals were found to be Ca, Mg, and Cl., Ca, Mg, Cl, and SO4, as well as Ca, Na, Mg, Cl, SO4, and HCO3. From the mass analysis, the first K, second Na, third Ca, fourth Mg, SO4 and fifth Cl, HCO3 were obtained. Finally, from the main component analysis, hydrogeochemical facies were found: Cl, SO4, Ca, HCO3, Mg, and Na, Respectively.
Evaluation of the Suitability of Sulfur Springs Water for Vital Uses by Studying the Physical, Chemical Properties of Some Sulfur Springs Water in the City of Hit
Authors: Fakhry Muammar A , Saleh Muafaq A , Nayyef Asmaa G
Published: August 2023

By studying some of the physical and chemical properties of the water of sulfur springs and identifying the nature of that water and the concentration of elements and ions in it and the percentage of salts, and by looking at the Iraqi environmental legislation and the World Health Organization (WHO), we find that the water of the studied springs is unfit for human and animal consumption, because of the concentration of dissolved salts in it, which Exceeding the general allowable rate, in addition to the high concentration of dissolved ions that lead to a change in the properties of that water. It can also be confirmed on the field that the water of those springs is rich in hydrogen sulfide gas (H2S), which is formed as a result of the oxidation of organic substances and the reduction of sulfate ions. In addition, most of the springs of the study area are characterized by the mixing of their water with oil derivatives, adding a state of pollution to that water, which increased the unfitness of that water for drinking purposes. Liquid petroleum (consisting of a complex mixture of different compounds, some of which are volatile or light, and some are heavy such as asphalt materials and bitumen), and natural gas such as methane, ethane, propane, and butane (Al-Jumaili and Ahmed; 2018). These factors and pollutants combined made that water unfit for drinking or human consumption. According to the classification of the American salinity laboratory for the year 1954, and the classification of the FAO for the year 1992, it is considered suitable water for irrigation purposes and watering field. In addition to the validity of spring water for industrial purposes, and its use for therapeutic purposes and hospitalization due to its richness in salts, elements and ions.
Study of the Euphrates River’s Water Quality in Front of and Behind the Haditha Dam in Anbar Province, Iraq
Authors: Jalal Arkan D , Ani Yasir Al , Thameel Salah S , Ismael Zainab M
Published: August 2023

Contaminants in natural water continue to be one of the largest environmental issues on the planet. This is due to the fact that due to population expansion, urbanization, agricultural practices, and industrialization, there is a significant increase in the demand for freshwater and a water crisis in arid and semi-arid areas. The present study aimed to assess the suitability of water quality at Haditha Dam. In this study, 9 parameters, including Nitrate NO3, Carbonate CO3, bicarbonate HCO3, Sulphate SO4, Chloride Cl, Calcium Ca, Magnesium Mg, Sodium Na, and Potassium K were measured and investigated to assess water quality for Haditha Dam Project in both sides (Behind and in front of the dam). The current study focuses on the examination of water quality data collected over a one-year period from both sides of the Euphrates River through the collection of 48 samples. The parameters that were examined used the accepted techniques. Findings showed that average concentrations were lowest during the dry season and highest during the rainy season for K, Ca, Na, Mg, Cl, and SO4. However, HCO3 and CO3 concentrations were the highest averages in the dry season, while the lowest average was in the wet season. The results were compared with Iraqi standards for water quality and the World Health Organization (WHO). The planning and logical management of water resources, including the possibility of using them for irrigation and drinking water, can benefit from this study. According to the findings, river water is deemed unsafe for drinking and human consumption, however it can be utilized for irrigation.
Response of Anatomical Characteristics of Nile Flower Eichhornia crassipes to Environmental Changes and their Impact on Tigris Water Quality
Authors: Alsahan Irfan W , Mohammad Hala A , Al-Blesh Adnan H
Published: August 2023

The current study was conducted on the Tigris River in the distance between Qayyarah district of Nineveh province and Baiji district of Salahuddin province by five stations (Al-Gayyarah, Jisr Al-Shirgat, Asdeira, Al-Zuwia and Almsahag). Anatomical Characteristics of Nile flower Eichhornia crassipes were studied. Some qualitative properties of river water were studied. The results indicated that there were significant differences between the study stations in all anatomical characteristics of the plant, Significant differences were found in the different study stations in all the characteristics of the upper and lower skin of the leaves of the Nile flower plants, it is the dimensions of stomata and its index and the average dimensions of the cells of the upper and lower skin. For the stems of the Nile flower plants, anatomical characteristics showed significant differences with different study stations. Al- Mosahak station achieved the highest stomatal dimensions of 15 and 13 μm for length and width respectively. Al-Gayyarah station excelled in the highest averages of the stomata index and average length × width of normal cells with values of 14 and 32 × 15 μm respectively. The highest mean of the physical characteristics of the river water was 1407 mg / L of total dissolved solids at the Al-Zuwia station in December, 8.4 for pH at Al-Gayyarah and Jisr Al-Shirgat stations during January, and 1.4 mg / L for BOD5 in Al-Gayyarah station during March, 2.3 mg / L for total hardness at Asdira station in February, 1.02 mg / L of nitrate at Almsahag station in December, 1.231 mg / L for sulfate at Al-Gayyarah station in January, 2.38 mg / L for sodium at Al-Zauwia station in December, and 1.2 mg / L for potassium at Almsahag station in March.
Influence of interface-sharpening on the ship’s wave system
Authors: Perić Robinson , Berndt Jannes , Abdel-Maksoud Moustafa
Published: August 2023

This article investigates the influence of the interface-sharpening algorithm on the wave height near ships in flow simulations. The focus is on finite-volume-based flow simulations with the volume of fluid (VOF) method to account for the two phases, gaseous air and liquid water. A common approach to obtain a comparatively sharp interface between the water phase and the air phase is to use interface-capturing approaches combined with interface-sharpening schemes. The present work demonstrates that the interface-sharpening schemes can contain case-dependent parameters, and that the optimum values for these parameters may not be known a priori. Therefore, if the parameters are not set correctly, the wave height at some distance to the ship may be unrealistically small or large. To demonstrate this, flow simulations of calm-water resistance of the KCS ship are performed with different discretizations and different parameters of the interface-sharpening scheme. The present simulation results are compared to experimental results to provide recommendations on the optimum choice of interface-sharpening parameters and guidelines for performing such flow simulations, to improve predictions of the ship’s wave system.
Hydrodynamic response of dual obliquely submerged non-uniform flexible thin plates
Authors: Singh Mansi , Gayen R
Published: August 2023

Examining inclined flexible plates with variable thickness becomes crucial when it comes to optimizing or achieving controlled reflection and transmission of waves, especially for the construction of breakwaters. Unlike horizontal breakwaters, inclined barriers have the ability to penetrate through numerous layers of the fluid, having different particle velocities and foster their interactions. This causes wave breaking which leads to loss of wave energy. Also, despite exhibiting a similar behavior, vertical structures do not attenuate waves as effectively as inclined ones do. Additionally, the resonant motion of the fluid trapped between two structures proves to enhance the attenuation, thus it is recommended to include dual structures in the model rather than just one. Therefore in the present study, we examine the water wave scattering phenomenon by a pair of symmetric flexible thin plates with non-uniform thickness obliquely submerged in deep water. We use the linear water wave theory and Kirchhoff’s thin plate theory to model the physical problem. The boundary value problem is converted into a system of coupled integral equations using repeated integration and Green’s integral theorem. Using appropriate approximations, this system is solved and its solutions are used to determine numerical values of different hydrodynamic quantities. Results of two horizontal as well as two vertical plates could be obtained from the present model, thus it is a very general model. Also results are illustrated to analyze the contribution of the thickness variation and the inclinations of the two flexible plates towards the wave scattering process and some related physical quantities.
A Numerical Sensitivity Analysis of Fluid-Structure Interaction Simulations on Slamming Loads and Responses
Authors: Hosseinzadeh Saeed , Topa Ameen , Tabri Kristjan
Published: August 2023

This paper presents a parametric study on the Multi Material Arbitrary Lagrangian–Eulerian (MMALE) method for hydroelastic analysis of a non-prismatic stiffened aluminium wedge. An explicit finite element formulation with a penalty-based coupling technique is employed to evaluate the impact-induced loads and responses during free-fall water entry. Based on the penalty factor, damping factor, and number of coupling points, a sensitivity analysis is carried out. It is shown that the penalty coupling method can generate high-frequency oscillations due to the nature of the phenomenon that may affect the predicted results of slamming loads. The computed results on the stiffened and unstiffened plates of the wedge are compared with published experimental data in terms of vertical acceleration, pressure distributions, and strain responses at different locations. A reasonable agreement can be found between the numerical results and the measured values. It is found that a combination of penalty and damping can improve the simulation results and reduce numerical instabilities in hydroelastic slamming simulations.
Numerical investigations of dam-break flow impacting on an elastic beam using various FSI coupling algorithms
Authors: Zhang Wenjie , Yang Xiaolong , Wang Jianhua
Published: August 2023

The occurrence of green water and slamming in severe sea conditions can often be simplified as a dam-break problem. The flow characteristics of dam-break are similar with those on a ship’s deck and can result in structural damage. In this study, the fluid-structure interaction (FSI) of dam-break flow impacting on an elastic beam is investigated based on CFD-FEM method. The FSI coupling is solved in a partitioned manner. The fluid field is solved by OpenFOAM and the structure is calculated by self-developed code using FEM. The two-way coupling algorithm has been implemented to update the mesh of the fluid field. An investigation on mesh independence and the comparison of results with other methods have been conducted to validate the simulation results. After that, three types of FSI coupling algorithms have been utilized to examine the impact on both computational accuracy and efficiency. It is studied that the computational accuracy of all three FSI coupling algorithms is in good agreement. The FSI coupling algorithm utilizing weak iteration exhibits excellent performance in terms of both computational accuracy and efficiency. For the strong coupling algorithm, it is crucial to make a rational selection of the outer and inner iteration numbers in PIMPLE loops.
Numerical Simulation of Ship-Pack Ice-Water Interaction and Motion of Pack Ice Based on CFD-DEM Method
Authors: Zou Ming , Tang Xiang-Jie , Zou Lu , Zou Zao-Jian
Published: August 2023

When a ship sails in pack ice area, it not only collides with the ice but also interacts with the water, generating ship-generated waves. The role and influence of ship-generated waves on the ship-ice-water interaction have not been thoroughly studied. In this study, a numerical model with ship-generated waves is established using a coupled Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM), and an appropriate contact model is selected for numerical simulations. Meanwhile, a simplified numerical model without ship-generated waves is proposed. By comparing the simulation results under the same simulation conditions with and without ship-generated waves, the effects of ship-generated waves on the phenomena of ship-ice-water interaction, longitudinal and lateral contact forces between the ship and pack ice, and ice resistance are analysed, along with the underlying mechanisms. The results indicate that the ship-generated waves can mitigate and reduce the collision intensity and contact frequency between the ship and pack ice, resulting in a decrease in the contact forces and ultimately achieving a significant reduction in ice resistance. Furthermore, this mitigation effect becomes more pronounced with increasing ship speed.
A CFD investigation of the effects of passing ship on a small size ice floe
Authors: Jiang Z , Suominen M , Tavakoli S , Kujala P , Hirdaris S
Published: August 2023

A RANS (Reynolds Averaged Navier-Stokes) CFD STAR-CCM+ model is used to investigate the hydrodynamic interactions between a ship and a circular ice floe. The overset mesh technique is employed to simulate the advancing movement of the passing ship. The ship has a hull of similar configuration to the KCS MOERI container ship. The ice floe has a diameter of 30% of the ship’s length and a thickness of 3 m. The paper primarily focuses on the motions of the ice floe and the hydrodynamic forces induced by the ship progressing in different speeds and calm water conditions. A parametric study on the influence of the ice floe surge and sway motions and associated hydrodynamic loads is presented. It is concluded that ship-generated waves can significantly affect the motions of the ice floe and the influence on sway is greater than that on surge. The ship speed is also found to have a distinct impact on ice floe motions.
An example of numerical ice tank based on DEM simulation and physical model testing
Authors: Tian Yukui , Yang Dongbao , Gang Xuhao , Yu Chaoge , Ji Shungying
Published: August 2023

The determination of ice loads on polar ships and offshore structures is of great significance for ice-resistant design, safe operation, and structural integrity management in ice-infested waters. The physical model testing carried out in ice tank/basin is usually an important technical approach to evaluate the ice loads, however, the high cost and time consumption make it difficult to perform multiple repetitions or large number of trials for this purpose. Recently, the rapid development of high-performance computation techniques provides a usable alternative where the numerical methods represented by the discrete element method (DEM) have made remarkable contributions to the ice load predictions. On basis of DEM simulation validated by physical model testing, numerical ice tank can be developed as an effective supplement to its counterpart. In this paper, such an example of numerical ice tank adopting GPU computational mechanism and DEM modelling algorithm was established with respect to the small ice model basin of China Ship Scientific Research Center (CSSRC-SIMB). The numerical ice tank was calibrated and further optimized with physical model tests on typical structures of vertical cylinder and inclined flat plate in level ice sheets by making agreements of both globe value and time history of the ice loads. Then it was practiced for modelling the tests of Wass bow advancing in level ice performed in SIMB separately. It is demonstrated by the comparisons of ice failure details and ice loads that the numerical ice tank can precisely simulate the ice-structure interactions and determine the ice loads under the same initial conditions of physical model testing. In the end, the advantages as well as the challenges of the numerical ice tank are discussed.
Impact of direct seakeeping computation on ship Underwater Keel Clearance prediction
Authors: Gallucci Filippo , Vernengo Giuliano
Published: August 2023

The continuous increase in worldwide ship traffic poses relevant challenges on the management of the onboard safety during navigation and specific operations. Among these issues, navigation in relatively shallow water areas, being either channels or port areas, is of major interest especially when rough weather conditions occur due to the increased risk of grounding. Such a problem, which is deeply related to the seakeeping performance of a ship, can be tackled by different perspectives. In the present paper, the approach proposed by the PIANC recommendations, typically used to design port and channels areas and infrastructures, are analysed from the perspective of ship design hence dealing with its operability. In particular, the dynamic Underwater Keel Clearance (UKC) of a ship is studied based on direct seakeeping computations to assess the effect of the operability conditions in terms of sea states and ship speed at different wave encounter angles.
Dynamic response of offshore triceratops under regular waves with tether postulated failure
Authors: Chandrasekaran Srinivasan , Rao Ganta Shanmukha
Published: August 2023

Triceratops are innovative offshore platforms that consist of a deck, three buoyant legs, and ball joints. Their deck is supported by buoyant legs, which, in turn, are restrained on the sea bed using taut-moored tubular tethers. Ball joints partially isolate the deck from the buoyant legs by restraining the transfer of rotations from the legs to the deck. Triceratops platforms exhibit a monolithic structural action in the vertical plane and a hybrid dynamic behavior resembling tension leg platforms and spar buoys. The present study investigates their dynamic response in regular waves. Response amplitude operators (RAOs) are estimated for intact and postulated failure conditions of the tethers. Based on detailed numerical investigations, it is seen that the pitch response of the deck increases significantly under the postulated failure of tethers, which are otherwise absent due to the presence of ball joints. Marginal change in surge response, even under tether failure, confirms the suitability of triceratops for ultra-deepwater installations. The fatigue life of tethers before and after postulated failure conditions is compared using the S-N curve approach and noticed that the adjacent tethers’ fatigue life reduces significantly under postulated failure conditions of tethers.
Numerical simulations of the flows past two parallel square columns by MPS method
Authors: Huang Congyi , Yang Xiaolong , Wan Decheng
Published: August 2023

The hydrodynamic interactions between an offshore platform and surrounding water mainly occurs in way of the pile legs, and the flow past the pile legs can be simplified to the flow past the columns. This is the reason why it is of great significance to simulate the flow around multiple columns with accuracy. In this paper, based on a mesh-less method, Moving Particle Semi-implicit (MPS) method, the MLParticle-SJTU solver is used to simulate the flow past two parallel square columns. Firstly, the reliability and accuracy of the solver is verified by simulating the Poiseuille flow, in which the no-slip boundary condition is applied. Then, the flow past two parallel square columns with different spacing between the two columns is simulated when the Reynold number is 40. The influence of spacing on flow pattern, force on columns and the vortex shedding frequency is analyzed. It is found that when the spacing is relatively small, small vortices will be attached to the surface of the columns. As the spacing ratio increases, periodic shedding of vortices will occur.
Shallow waters resistance of an accelerating ship
Authors: Liu Y H , Terziev M
Published: August 2023

This paper investigates the acceleration resistance of a vessel in shallow waters using potential flow and CFD methods. Results indicated a pronounced resistance peak near the critical depth Froude number. The peak’s location and magnitude were sensitive to acceleration intensity and water depth. Excellent agreement between potential flow and CFD methods was found in low and high depth Froude number ranges, suggesting their effectiveness and cost-efficiency. However, non-linear effects affected the resistance peak’s magnitude and position, leading to slight disagreements between the methods. The solvers’ variation was observed to be sensitive to the investigated parameters.
Study of Influencing Factors on CFD Method and Separated Flow by the Virtual Static Captive Test
Authors: Yang C , Zeng K , Chu J L , Han Y , Gu M
Published: August 2023

In this paper, Computational Fluid Dynamic (CFD) methods are adopted to predict the manoeuvring behaviour of the KCS benchmark model. At first instance, the model is calibrated on the basis of three factors namely (a) turbulence model, (b) grid size and (c) time step. Secondly, a Static Oblique Towing Test (OTT) that utilises the SST K-ω turbulence model with a grid number of 1.64 million and a time step of 0.01 s is conducted. The maximum difference of the lateral force between the port and starboard ship sides is observed at x/Lpp
= 0.055. Finally, application of Reynold Averaged Navier Stokes (RANS) and Dettached Eddy Simulation (DES) CFD models indicates that the latter may be preferable in terms of capturing the oblique flow field.
Multi-scale characteristics investigation of sheet/cloud cavitation
Authors: Tian B C , Li L M , Wu Q , Huang B , Wang G Y
Published: August 2023

Sheet and cloud cavitation involve the formation of large-scale cavities and microbubbles across a wide range of length scales. In this study, a two-way coupling Eulerian-Lagrangian algorithm was utilized to simulate the cavitating flow around a NACA66 hydrofoil at an incidence of 8 degrees and a cavitation number of 1.2. The large eddy simulation (LES) and volume of fraction (VOF) methods are used to capture the large scale vapor structures in Eulerian frame. Meanwhile, the discrete bubble model (DBM) and simplified Rayleigh-Plesset equation are implied to solve the dynamic of Lagrangian microbubbles smaller than local grid scale. The results indicate that large-scale cavities are periodically shed downstream, influenced alternatively by the re-entrant jet and shock wave mechanisms, resulting in periodic variations of both the number and Sauter mean diameter of microscale bubbles. During the quasi-periodic evolution process of sheet/cloud cavitation, the microbubbles scatter around the large scale cavities where have strong turbulence intensity and high vorticity, and the probability density function of discrete bubble diameter similarly conforms to Gamma distribution with the dominant bubble size between 30 and 70μm. During the growth of an attached cavity, the number density of bubbles follows a power-law scaling with a value of -5/3 on radius. For the other stages, the bubble size spectrum of smaller microbubbles exhibits a -2/3 power-law scaling when the diameter of the microbubble is less than 200 μm. For larger bubbles with a diameter greater than 300 μm, the bubble density is proportional to the bubble radius to the power of -6.
Rudder hydrodynamics behind a propeller rotating ahead and astern
Authors: Lu Suli , Boucetta Djahida , Hoydonck Wim Van , Lataire Evert , Delefortrie Guillaume
Published: August 2023

Ships sailing in harbour environments will experience four-quadrant manoeuvres, based on the direction of ship velocity and propeller rate. A better understanding of ship hydrodynamics in such manoeuvres will contribute to the navigation safety. Aimed at ships equipped with a conventional single propeller and single rudder, the hydrodynamic performance of a rudder with the engine ahead and astern is studied. The KP505 propeller and NACA 0018 semi-balanced rudder (from the KCS benchmark ship) are selected for numerical studies for extended experimental data published. After validating numerical methods with open-water test data for the single propeller and the single rudder, CFD simulations based on RANS methods are conducted for different advance ratios ahead and astern, with rudder deflections ranging from 0 to 15 degrees. To understand propeller impact on lift and drag forces of the rudder in different working conditions, inflow to the rudder in propeller slipstreams are analysed by extracting the flow field data in different profiles along the rudder span. Streamlines around the rudder and pressure distributions on the rudder surfaces, along with the turbulent kinematic energy distributions and the vortex structures visualised by Q-criterion, are compared to reveal propeller-rudder interaction mechanisms in ahead and astern conditions. The study shows that the propeller rotation mode has a significant impact on rudder inflow patterns, and induced rudder forces change in different trends with propeller loading variations.
Tribological properties of oil-impregnated porous polyimide modified by rare-earth compounds
Authors: Liu Li , Liu Jinyang , Yin Shunli , Li Kai , Hua Licheng , Zhou Ningning , Hu Xudong , Li Jinbang
Published: August 2023

Porous polyimide (PPI) exhibits good tribological performances due to excellent oil-storage properties. Porous structure could store lubricant but also make PPI materials difficult to be strengthened by most fillers, because fillers will destroy the pore structure and reduce the strength significantly. Rare-earth compounds (RECs) have high surface activity, which allow them to bond well with polymer. In this study, the tribological properties of REC modified PPIs were investigated using a ball-on-disc tribometer, along with an analysis of oil-impregnated properties, including oil content, oil retention, oil contact angle and oil absorption speed. The mechanical properties, including hardness (Shore D), impact strength and tensile strength, were tested to evaluate the effect of RECs. The results show that CeF3 and LaF3 fillers can lead to an increase of about 40% in oil content of PPI. PrF3 modified PPI were found to have better oleophilic properties, as the oil contact angle reduced 33% compared with pure PPI and oil retention could reach 88% after 120 min centrifugation. Moreover, PrF3 can enhance the surface hardness, impact strength and wear resistance performance of PPI despite a slight decrease in tensile strength. Better oil-impregnation and mechanical properties of PPI modified by PrF3 effectively reduce the friction and wear.
Fabrication of superhydrophobic surface by a dimensional change in surface topography of microchannel on polymer substrate through induction-aided hot embossing: parametric investigation and optimization
Authors: Deshmukh Swarup S , Rana Pinal , Goswami Arjyajyoti
Published: August 2023

Hot embossing (HE) is a micro-fabrication technique employed to create micron-scale patterns on the polymer substrate. An in-house induction-assisted hot embossing (IHE) setup was fabricated to complete the embossing in a short duration as compared to traditional hot embossing process. This work alters the polymer surface topography to make it superhydrophobic for self-cleaning. Fiber laser machining was used to produce four-microchannel designs on an Aluminum-6061 plate in which the microchannel width was varied from 600μm to 150μm while maintaining a constant adjacent distance of 300μm. This textured plate is employed as a mold in the IHE setup. IHE process parameters, embossing temperature, pressure, time, and deembossing temperature were varied to emboss the mold designs on a polyethylene terephthalate substrate. Thereafter, the embossed microchannel height, surface roughness, and water contact angle perpendicular to the embossed microchannels (WCA⟂) were calculated. The parametric analysis examined how operational factors affected the output. The experiment was done as per the central composite design (experimental design) part of the design-of-experiments useful in the response surface model. Parametric research demonstrates that embossed microchannel height and width had a maximum effect on WCA⟂. Type-IV microchannels with 150μm width demonstrated the highest WCA⟂. The WCA⟂was mostly impacted by embossed microchannel height; hence a regression model was created using type-IV channel height data. Analysis of variance showed that embossing temperature mainly impacts microchannel height. The recently invented Jaya-algorithm optimized this model to increase embossed microchannel height and WCA⟂. Setting the parameters at the best level predicted by Jaya-algorithm yielded an embossed microchannel height inaccuracy of 2.18%. The WCA⟂measured on the surface of a sample prepared at the best parameters was found to be 154.71°±2°. Lastly, FTIR (Fourier-transform-infrared-spectroscopy) test showed no chemical composition change between the embossed and bare samples.
Room-temperature fabrication of flexible oxide TFTs by co-sputtering of IGZO and ITO
Authors: Wang Yan , Tang Yingjie , Chen Yitong , Li Dingwei , Ren Huihui , Liu Guolei , Li Fanfan , Jin Ran , Zhu Bowen
Published: August 2023

Amorphous oxide semiconductors, especially indium gallium zinc oxide (IGZO), have been widely studied and obtained significant progress in flexible thin-film transistors (TFTs) due to the high carrier mobility and low deposition temperature. However, a further annealing step is generally required to activate electrical properties and improve the device performance, which limited their applications in flexible electronics. In this study, we achieved flexible TFTs and arrays using co-sputtered IGZO and indium tin oxide (ITO) as channels deposited at room temperature without post-annealing. It was found that better transistor switching properties could be effectively achieved by regulating the sputtering power of ITO in the co-sputtered deposition. The device performance is comparable to that of the conventional oxide TFTs with high annealing temperatures (⩾300 °C), exhibiting a high saturation mobility (μ
sat) of 15.3 cm2 V−1s−1, a small subthreshold swing (SS) of 0.21 V dec−1, and a very high on–off ratio (I
on/off) of 1011. In addition, a 12 × 12 flexible TFT array was achieved with uniform performance owing to the low-temperature processing advantage of this technique. The flexible TFTs exhibited robust mechanical flexibility with a minimum bending radius of 5 mm and bending cycles up to 1000. Furthermore, an inverter based on co-sputtered IGZO and ITO was demonstrated with the maximum gain of 22. All these achievements based on the proposed TFTs without post-annealing process are expected to promote the applications in advanced flexible displays and large-area integrated circuits.
Defect-induced weak collective pinning in superconducting YB6 crystals
Authors: Pribulová Zuzana , Marcin Miroslav , Kačmarčík Jozef , Gabáni Slavomír , Flachbart Karol , Shitsevalova Natalya , Mori Takao , Sluchanko Nikolay , Anisimov Mikhail , Cambel Vladimír , Šoltýs Ján , Marcenat Christophe , Klein Thierry , Samuely Peter
Published: August 2023

In a previous study (2017 Phys. Rev. B
96 144501), a strong variation in the superconducting transition temperature T
c of YB6 differing by a factor of two has been explained by a change in the density of yttrium and boron vacancies tuning the electron–phonon interaction. Here, by using an array of miniature Hall probes, we address the penetration of the magnetic field, pinning, and critical current density on a series of YB6 single crystals with T
c variation between 4.25 and 7.35 K. The analysis of the superconducting and normal-state specific heat characteristics allowed us to determine T
c and the stoichiometry of our samples. We observed almost no pinning in the most stoichiometric YB6 crystal with the lowest T
c. Upon increasing the number of vacancies weak pinning appears, and the critical current density is enhanced following the increased transition temperature in a linear variation. We argue that such an increase is, within weak collective pinning theory, consistent with the increasing number of vacancies that serve as pinning centers.
Self-healing metal matrix composite of nitinol wire-reinforced A356 alloy matrix by stir casting technology
Authors: Sharma Sumit , Nandan Gopal , Tyagi R K
Published: August 2023

The current demand for novel and self-healing material in today’s industries is one of the key challenges. Many engineering applications required tailored properties including self-healing characteristics in novel engineering materials. In this regard, an attempt is made to develop the metal matrix composite of aluminum A356 alloy by utilizing the properties of Nitinol alloy (wire) through a semi-solid metal processing technique. The investigation was validated by light-microscope images of the developed material. Further, filed emission scanning electron microscopy images are taken from the specimens for morphological examination. The elemental confirmation of the produced material is conducted through Energy Dispersive X-Ray Analysis (EDX) spectrum. The results revealed the random dispersion of reinforcement in the matrix phase and EDX confirms that the major constituents of A356 alloy and the Nitinol wires. At last, the crack analysis is conducted before and after hearing which reveals that the interlocks of Nitinol wire with the alpha Al phase of base alloy can provide the ability to close the crack and it can recover the deformed surface by 17.35%.
Singular hermitian metrics and the decomposition theorem of Catanese, Fujita, and Kawamata
Authors: Lombardi Luigi , Schnell Christian
Published: August 2023

We prove that a torsion-free sheaf

F

\mathcal {F}

endowed with a singular hermitian metric with semi-positive curvature and satisfying the minimal extension property admits a direct-sum decomposition

F

≃

U

⊕

A

\mathcal {F}\simeq \mathcal {U}\oplus \mathcal {A}

where

U

\mathcal {U}

is a hermitian flat bundle and

A

\mathcal {A}

is a generically ample sheaf. The result applies to the case of direct images of relative pluricanonical bundles

f
∗

ω

X

/

Y

⊗
m

f_* \omega _{X/Y}^{\otimes m}

under a surjective morphism

f
:
X
→
Y

f\colon X \to Y

of smooth projective varieties with

m
≥
2

m\geq 2

. This extends previous results of Fujita, Catanese–Kawamata, and Iwai.
Mean dimension of natural extension of algebraic systems
Authors: Liang Bingbing , Shi Ruxi
Published: August 2023

Mean dimension may decrease after taking the natural extension. In this paper we show that mean dimension is preserved by natural extension for an endomorphism on a compact metrizable abelian group. As an application, we obtain that the mean dimension of an algebraic cellular automaton coincides with the mean dimension of its natural extension, which strengthens a result of Burguet and Shi [Israel J. Math. (to appear).] with a different proof.
The successive dimension, without elegance
Authors: Menni Matías
Published: August 2023

Experience shows that the poset of levels (or dimensions) of the topos of presheaves on some elegant Reedy categories may be equipped with a monotone increasing ‘successor’ function which, as the case of simplicial sets illustrates, is different from Lawvere’s Aufhebung in general. We prove that a similar result holds for the topos of presheaves on a small category with split-epi/mono factorizations; a typical feature of categories that are Reedy elegant, or skeletal, or graphic (von Neumann-)regular, but more general. In fact, we show that the more general ‘successor’ may be described as a function on the poset of full subcategories of the site that are closed under subobjects.
Construction of 𝑝-energy and associated energy measures on Sierpiński carpets
Authors: Shimizu Ryosuke
Published: August 2023

We establish the existence of a scaling limit

E

p

\mathcal {E}_p

of discrete

p
p

-energies on the graphs approximating a generalized Sierpiński carpet for

p
>

d

A
R
C

p > d_{\mathrm {ARC}}

, where

d

A
R
C

d_{\mathrm {ARC}}

is the Ahlfors regular conformal dimension of the underlying generalized Sierpiński carpet. Furthermore, the function space

F

p

\mathcal {F}_{p}

defined as the collection of functions with finite

p
p

-energies is shown to be a reflexive and separable Banach space that is dense in the set of continuous functions with respect to the supremum norm. In particular,

(

E

2

,

F

2

)

(\mathcal {E}_2, \mathcal {F}_2)

recovers the canonical regular Dirichlet form constructed by Barlow and Bass [Ann. Inst. H. Poincaré Probab. Statist. 25 (1989), pp. 225–257] or Kusuoka and Zhou [Probab. Theory Related Fields 93 (1992), pp. 169–196]. We also provide

E

p

\mathcal {E}_{p}

-energy measures associated with the constructed

p
p

-energy and investigate its basic properties like self-similarity and chain rule.
Osh-dependent and -independent Regulation of PI4P Levels During Polarized Growth ofSaccharomyces cerevisiae
Authors: Heckle Lindsay A. , Kozminski Keith G.
Published: August 2023

For polarized secretion to occur, secretory vesicles must mature to a docking-competent state. In current models, an OSBP-related protein, Osh4p, modulates vesicle-associated PI4P levels along the secretory pathway. Utilizing the lipid-binding domain P4M and live-cell imaging of Saccharomyces cerevisiae we showed that, contrary to existing models, vesicle-associated PI4P levels remain constant as vesicles traffic from the TGN to the PM. Furthermore, all members of the Osh protein family play a role in maintaining intracellular PI4P distribution. We propose a new model for polarized secretion by S. cerevisiae in which vesicular PI4P levels remain constant in an Osh4p-independent manner.