bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Bond Coat Roughness on Adhesion of Thermal Barrier Coatings Deposited by the Electron Beam–Physical Vapour Deposition Process
Authors: Maciaszek Grzegorz , Nowotnik Andrzej
Published: August 2024

Thermal barrier coatings (TBCs) are effective protective and insulative coatings on hot section components of turbine engines. The quality and subsequent performance of the TBCs are strongly dependent on the adhesion between the coating and the metal substrate. The adhesion strength of TBCs varies depending on the substrate materials and coating, the coating technique used, the coating application parameters, the substrate surface treatments, and environmental conditions. Therefore, the roughness of the substrate surface has a significant effect on the performance of the TBC system. In this work, the roughness and microstructure of the 7YSZ (7 wt.% yttria-stabilised zirconia) top coat under different bond coat roughness treatments were studied. The purpose of this paper was to investigate the influence of the roughness of the bond coat on the adhesion of 7YSZ TBCs prepared by the electron beam–physical vapour deposition (EB-PVD) process. The VPA (vapour phase aluminium) bond coat was deposited on Inconel 718 nickel superalloy substrate using the above-the-pack technique. The ceramic top coat was applied to the bond coat using the EB-PVD process. The dependence between the TBC coating roughness and the bond coat roughness was determined. Adhesion strength measurements were performed according to the ASTM C 633 standard test method. The highest adhesion value observed in the tensile adhesion tests was 105 MPa. However, it was not determined whether the surface roughness of the bond coat affects the adhesion of the 7YSZ top coat.
Potential of Plant Stem Cells as Helpful Agents for Skin Disorders—A Narrative Review
Authors: Hermosaningtyas Anastasia Aliesa , Chanaj-Kaczmarek Justyna , Kikowska Małgorzata , Gornowicz-Porowska Justyna , Budzianowska Anna , Pawlaczyk Mariola
Published: August 2024

Recently, cellular senescence has been of great interest due to its pleiotropic nature and association with both physiological (e.g., aging) and pathological conditions. Excessive accumulation of reactive oxygen species (ROS) can induce inflammation, which accelerates skin aging (also premature aging) and may cause several dermatoses. It has been postulated that plant-derived antioxidants, especially plant stem cells, may prevent cell damage by preserving stemness and reducing cellular senescence by ROS targeting. Therefore, this paper aims to review and summarize recent developments and innovative techniques associated with plant-derived stem cells in relation to skin senescence. This review also presents the possible pathways involved in this process. Particular attention was paid to the potential applications of plant stem cells as senostatics/senomorphics produced by modern plant biotechnology methods. Furthermore, the advantages, limitations, and future directions of this technology are also discussed. This knowledge allows the development of personalized strategies to create a healthy balance in skin care. Plant stem cells could be a more feasible and practical approach to combating the adverse effects of skin senescence processes.
Quantitative Determination of Partial Voxel Compositions with X-ray CT Image-Based Data-Constrained Modelling
Authors: Wang Haipeng , Mu Xinsheng , Zhou Xinyue , Yang Yu-Shuang
Published: August 2024

X-ray CT imaging is an important three-dimensional non-destructive testing technique, which has been widely applied in various fields. However, segmenting image voxels as discrete material compositions may lose information below the voxel size. In this study, six samples with known volume fractions of compositions were imaged using laboratory micro-CT. Optical microscopic images of the samples reveal numerous small particles of compositions smaller than the CT voxel size within the samples. By employing the equivalent energy method to determine the X-ray beam energy for sample imaging experiments, data-constrained modelling (DCM) was used to obtain the volume fractions of different compositions in the samples for each voxel. The results demonstrated that DCM effectively captured information about compositions occupying CT voxels partially. The computed volume fractions of compositions using DCM closely matched the known values. The results of DCM and four automatic threshold segmentation algorithms were compared and analyzed. The results showed that DCM has obvious advantages in processing those samples containing a large number of particles smaller than the CT voxel size. This work is the first quantitative evaluation of DCM for laboratory CT image processing, which provides a new idea for multi-scale structure characterization of materials based on laboratory CT.
A Study on the Optimization of Water Jet Decontamination Performance Parameters Based on the Response Surface Method
Authors: Qiu Xianyan , Wang Mengkun , Chen Bingzheng , Ai Yang
Published: August 2024

The substrate that adheres between the teeth of the traveling track plate during the operation of a deep-sea polymetallic nodule mining vehicle affects the driving performance, so this study aimed to investigate the effect of the water jet on the cleaning and decontamination performance of the track under different conditions. An optimization design method based on response surface methodology (RSM) is proposed. Based on the Box–Behnken design, the optimization variables of jet pressure, jet target distance, and impact angle, and the target response of jet strike pressure on tracks, were selected, and the numerical simulation method was combined with the response surface method to establish the regression model of the response of each optimization variable to the jet strike pressure on tracks and to determine the optimal parameter combinations. The study findings indicate that the primary factor influencing the pressure of the jet striking the crawler is the jet pressure. The hierarchical order of influence on the pressure of the jet striking the crawler, under the interaction of the three factors, is as follows: jet pressure and impact angle, jet pressure and target distance of the jet, and target distance of the jet and impact angle. The maximum pressure of the jet striking the crawler occurs when the jet pressure is 0.983 MPa, the target distance is 0.14 m, and the impact angle is 89.5°. Overall, the proposed design serves as a systematic framework for parameter optimization in the cleaning and decontamination process, and the research method and results provide theoretical references for the optimal design of mining truck desorption efficiency, which is critical for increasing mining efficiency and lowering energy consumption.
Perceived Usefulness of a Mandatory Information System
Authors: Fridkin Shimon , Greenstein Gil , Cohen Avner , Damari Aviran
Published: August 2024

This study examines the adoption and implementation of an information system in a mandatory context focusing on an Israeli governmental organization. The system referred to as “Slot” is an online platform for managing educational activities within this organization. The research investigates the impact of the system on its functionality users and the results of its usage. Additionally, the study explores factors that influence the acceptance and utilization of information systems, including whether the willingness to use the system under instruction depends on other variables. The key findings of this study are: perceived ease of use significantly and positively influences perceived usefulness; perceived usefulness significantly and positively affects symbolic adoption; and supervisor influence significantly and positively impacts perceived usefulness. Moreover, the relationship between perceived ease of use and symbolic adoption is entirely mediated by perceived usefulness as is the relationship between supervisor influence and symbolic adoption. The study’s limitations include the relatively small sample size and the specific context of the research, which may limit the generalizability of the findings. Future research could explore similar models in different organizational settings to validate and extend the applicability of the results. The findings suggest that enhancing the perceived ease of use and usefulness of mandatory systems can significantly impact their symbolic adoption, with supervisory influence playing a crucial role in shaping user perceptions. These insights can inform strategies for more effective implementation and management of information systems in mandatory settings.
Numerical Modeling for Tunnel Lining Optimization
Authors: Suárez-Fino Jose Francisco , Mayoral Juan M.
Published: August 2024

The construction of tunnels excavated by the conventional method in densely populated urban environments requires an adequate characterization of the loads acting on the primary lining during the excavation process, to ensure that the ground is deformed and stresses around the tunnel are relieved, simultaneously complying with the failure and serviceability limits of international standards while minimizing damage to nearby structures. In this paper, common lining design criteria are revisited, through the numerical simulation of an instrumented tunnel section which is part of a 4.5 km long metro line currently under construction in Mexico City. Key needs for improvement in current design approaches are identified. The tunnel was instrumented with load cells, extensometers, and topographical references for convergences and divergences. A three-dimensional finite difference model of the instrumented section was developed, and the load transfer mechanisms between the excavated soil and the primary lining were analyzed. Then, the numerical simulation of the contribution of the secondary lining in the overall stability for sustained load was established, along with the expected ground settlements, which can significantly affect nearby structures. Results gathered from this research are key for updating lining design criteria for urban tunnels built in stiff brittle soils.
Numerical Modeling and Analysis of Pendant Installation Method Dynamics Using Absolute Nodal Coordinate Formulation
Authors: Chen Yongkang , He Shiping , Luo Xinhao
Published: August 2024

Accurately simulating the deployment process of coupled systems in deep-sea environments remains a significant challenge. This study employs the Absolute Nodal Coordinate Formulation (ANCF) to dynamically model and analyze multi-body systems based on the Pendant Installation Method (PIM). Utilizing the principle of energy conversion, this study calculates the stiffness, generalized elastic forces, mass matrices, and Morison equation, formulating a motion equation for the dynamic coupling of nonlinear time-domain forces in cables during pendulum deployment, which is numerically solved using the implicit generalized-α method. By comparing the simulation results of this model with those from the catenary theory model, the advanced modeling capabilities of this model are validated. Lastly, the sensitivity of the multi-body system under various boundary conditions is analyzed. The results indicate that deployment operations are more effective in environments with strong ocean currents. Furthermore, upon comparing the impacts of structural mass and deployment depth on the system, it was found that deployment depth has a more significant effect. Consequently, the findings of this study provide a scientific basis for formulating subsequent optimization strategies.
Study of the Improvement of Disintegration Efficiency and Antibacterial Properties of Disposable Toilet Seat Cover Sheet Made of Cellulose Fibers
Authors: Park Ju-Hyun , Kim Chul-Hwan , Park Hyeong-Hun , Lee Tae-Gyeong , Park Min-Sik , Lee Jae-Sang
Published: August 2024

The growing prevalence of disposable toilet seat covers in public restrooms stems from concerns about personal hygiene, given the direct contact between the seat and various users’ skin. To enable these disposable cover sheets to be flushed down the toilet instead of being discarded in the trash, they must possess specific properties. These include rapid water absorption for quick disintegration, strength to endure user movement or moisture on the toilet seat surface, and a comfortable texture. To address these challenges, the study investigated the disintegration characteristics of flushable cover sheets prepared under different refining conditions. Alkyl ketene dimer (AKD) was also employed to enhance water resistance, while an organic antibacterial agent was used to impart antimicrobial properties. The findings revealed that adding 0.2% AKD and 1% organic antibacterial agent to pulp stock with a freeness of about 650 mL CSF was suitable for manufacturing disposable cover sheets with disintegration characteristics like toilet tissue paper.
Generative Adversarial Networks in Business and Social Science
Authors: Ruiz-Gándara Africa , Gonzalez-Abril Luis
Published: August 2024

Generative adversarial networks (GANs) have become a recent and rapidly developing research topic in machine learning. Since their inception in 2014, a significant number of variants have been proposed to address various topics across many fields, and they have particularly excelled not only in image and language processing but also in the medical and data science domains. In this paper, we aim to highlight the significance of and advancements that these GAN models can introduce in the field of Business Economics, where they have yet to be fully developed. To this end, a review of the literature of GANs is presented in general together with a more specific review in the field of Business Economics, for which only a few papers can be found. Furthermore, the most relevant papers are analysed in order to provide approaches for the opportunity to research GANs in the field of Business Economics.
Optimization of Agricultural Tractor Engine Hood Forming Quality Based on Neural Network Genetic Algorithm Function
Authors: Wang Shuo , Wu Yan , Ma Yanman , Wang Mingtao
Published: August 2024

To improve the forming quality of agricultural tractor engine hood and effectively solve the problems of wrinkling and cracking during the drawing forming process, DYNAFORM 5.9 finite element software was used for numerical simulation of the part. Based on a comprehensive scoring method of orthogonal experiments and grey relational analysis, the critical process parameters affecting the “maximum thickening rate” and “maximum thinning rate” were determined. Latin hypercube sampling was used to randomly sample the key process parameters, and the sampled samples served as the data basis for the optimization stage of the neural network genetic algorithm function; an optimization model of the neural network genetic algorithm function was established, with the key process parameters, and the “maximum thickening rate” and “maximum thinning rate” as inputs and outputs respectively, to construct a nonlinear mapping relationship and optimize the process parameters. The study showed that the blank holder force and die clearance had the greatest impact on the “maximum thickening rate” and “maximum thinning rate”, identifying them as key process parameters; the optimal process parameter combination was the blank holder force of 462.71 kN, the die clearance of 1.09 mm, and corresponding “maximum thickening rate” and “maximum thinning rate” of 3.97% and 25.96%, respectively. Overall, this research provides a practical optimization strategy to solve the quality issues of the engine hood, offering a theoretical basis for its actual production and processing with significant practical application value.
Experimental Flow Performance Investigation of Francis Turbines from Model to Prototype
Authors: Mirza Umar Baig , Huang Xingxing , Wang Zhengwei
Published: August 2024

Investigating the flow performance of Francis turbines from model to prototype is a complex but essential process for ensuring reliable and efficient turbine operation in hydropower plants. It ensures that Francis turbine designs operate efficiently under various operating conditions, extending from laboratory reduced-scale models to full-scale prototype installations. In this investigation, a Francis turbine model was tested under different operating conditions, and its properties were measured, including torque, hydraulic efficiency, power output, cavitation coefficient, rotational speed, flow rate, and pressure pulsations. The results of the Francis turbine model test indicate that it achieved the maximum torque with the designed discharge and designed head. The cavitation coefficient consistently remained higher than the critical cavitation coefficient. The initial cavitation bubbles were observed at 50% partial load but disappeared at full load. Pressure pulsations under different operating conditions showed the maximum peak-to-peak amplitude appearing at the turbine inlet domain and the minimum amplitude occurring at the draft tube elbow. A hill chart shows that the model’s best efficiency was 93.66%, and the estimated best efficiency of the prototype was 95.03% at the design head. The conclusions and methodology of this study can be generalized to other similar hydraulic turbines, especially prototype Francis turbines that lack experimental results.
Orthogonal Matrix-Autoencoder-Based Encoding Method for Unordered Multi-Categorical Variables with Application to Neural Network Target Prediction Problems
Authors: Wang Yiying , Li Jinghua , Yang Boxin , Song Dening , Zhou Lei
Published: August 2024

Neural network models, such as BP, LSTM, etc., support only numerical inputs, so data preprocessing needs to be carried out on the categorical variables to convert them into numerical data. For unordered multi-categorical variables, existing encoding methods may produce dimensional catastrophes and may also introduce additional order misrepresentation and distance bias in neural network computation. To solve the above problems, this paper proposes an unordered multi-categorical variable encoding method O-AE using orthogonal matrix for encoding and encoding representation learning and dimensionality reduction via an autoencoder. Bayesian optimization is used for hyperparameter optimization of the autoencoder. Finally, seven experiments were designed with the basic O-AE, Bayesian optimization of the hyperparameters of the autoencoder for O-AE, and other encoding methods to encode unordered multi-categorical variables in five datasets, and they were input into a BP neural network to carry out target prediction experiments. The results show that the experiments using O-AE and O-AE-b have better prediction results, proving that the method proposed in this paper is highly feasible and applicable and can be an optional method for the data processing of unordered multi-categorical variables.
Optimization of Formula for Chromium-Free Zinc–Aluminum Coatings Based on Extension Analytic Hierarchy Process
Authors: Zhu Fu , Xin Yu , Tian Wei , Tang Yan , Hou Lin , Gao Yuhang
Published: August 2024

The service performance of chromium-free zinc–aluminum coatings exhibits characteristics from multiple perspectives. Fully considering the physical properties, corrosion resistance, and economic viability of the coatings, this study incorporates the concepts of “domain” and “degree” from extenics theory into the analytic hierarchy process to optimize the formulation of chromium-free zinc–aluminum coatings. The findings reveal that the extension analytic hierarchy process takes into account the diversity of evaluation indicators, enhancing the objectivity and accuracy of the comprehensive evaluation results. Nine formulations were developed using a four-factor, three-level orthogonal experiment to evaluate the effects of metal powder, PEG-400, KH-560, and sodium molybdate on the service performance of chromium-free zinc–aluminum coatings. Utilizing an extensible hierarchical sorting weight system alongside a performance index grading and scoring method, 3# emerged with the highest score, indicating the best overall performance. The research outcomes offer innovative insights and technical support for optimizing the formulations of chromium-free zinc–aluminum coatings and other coatings.
Effects of Physically Adsorbed and Chemically Immobilized RGD on Cell Adhesion to a Hydroxyapatite Surface
Authors: Leitão Melissa , Mavropoulos Elena , Sader Marcia Soares , Costa Andrea , Lopez Elvis , Fontes Giselle Nogueira , Granjeiro José Mauro , Romasco Tea , Di Pietro Natalia , Piattelli Adriano , Mourão Carlos Fernando , Gomes Alves Gutemberg , Malta Rossi Alexandre
Published: August 2024

The strategies used to associate peptide arginylglycylaspartic acid (RGD) with calcium phosphate grafts to enhance cell–biomaterial interactions have been controversial in the literature. Several works have demonstrated that RGD-functionalized hydroxyapatite (HA) surfaces improve cell adhesion, whereas others claim that RGD-loaded HA has an inhibitory effect when serum is present in the biological medium. To investigate such contradictory results, we associated RGD with the HA surface using physical adsorption and chemical bonding methods and evaluated the cell adhesion and spreading in pre-osteoblasts culture with and without fetal bovine serum (FBS). The effect of functionalization methods on the physicochemical characteristics of both surfaces was analyzed using multiscale techniques. Adsorption assays of serum allowed us to estimate the impact of the association method on the HA surface’s reactivity. Physically adsorbed RGD did not increase the number of adhered cells due to the weak interactions between the peptide and the surface. Although chemical binding stabilizes RGD on the HA, the functionalization procedure covered the surface with molecules such as (3-aminopropyl)triethoxysilane (APTEs) and carbodiimide, changing the surface’s chemical activity. Serum protein adsorption decreased by 90%, revealing a significant reduction in the surface interactions with molecules of the biological medium. The present study’s findings showed that the RGD’s physical association with HA did not improve cell adhesion and that this phenomenon is highly dependent on the presence of serum proteins.
A Novel Low-Complexity and Parallel Algorithm for DCT IV Transform and Its GPU Implementation
Authors: Chiper Doru Florin , Dobrea Dan Marius
Published: August 2024

This study proposes a novel factorization method for the DCT IV algorithm that allows for breaking it into four or eight sections that can be run in parallel. Moreover, the arithmetic complexity has been significantly reduced. Based on the proposed new algorithm for DCT IV, the speed performance has been improved substantially. The performance of this algorithm was verified using two different GPU systems produced by the NVIDIA company. The experimental results show that the novel proposed DCT algorithm achieves an impressive reduction in the total processing time. The proposed method is very efficient, improving the algorithm speed by more than 4-times—that was expected by segmenting the DCT algorithm into four sections running in parallel. The speed improvements are about five-times higher—at least 5.41 on Jetson AGX Xavier, and 10.11 on Jetson Orin Nano—if we compare with the classical implementation (based on a sequential approach) of DCT IV. Using a parallel formulation with eight sections running in parallel, the improvement in speed performance is even higher, at least 8.08-times on Jetson AGX Xavier and 11.81-times on Jetson Orin Nano.
Semantic Segmentation of Urban Remote Sensing Images Based on Deep Learning
Authors: Liu Jingyi , Wu Jiawei , Xie Hongfei , Xiao Dong , Ran Mengying
Published: August 2024

In the realm of urban planning and environmental evaluation, the delineation and categorization of land types are pivotal. This study introduces a convolutional neural network-based image semantic segmentation approach to delineate parcel data in remote sensing imagery. The initial phase involved a comparative analysis of various CNN architectures. ResNet and VGG serve as the foundational networks for training, followed by a comparative assessment of the experimental outcomes. Subsequently, the VGG+U-Net model, which demonstrated superior efficacy, was chosen as the primary network. Enhancements to this model were made by integrating attention mechanisms. Specifically, three distinct attention mechanisms—spatial, SE, and channel—were incorporated into the VGG+U-Net framework, and various loss functions were evaluated and selected. The impact of these attention mechanisms, in conjunction with different loss functions, was scrutinized. This study proposes a novel network model, designated VGG+U-Net+Channel, that leverages the VGG architecture as the backbone network in conjunction with the U-Net structure and augments it with the channel attention mechanism to refine the model’s performance. This refinement resulted in a 1.14% enhancement in the network’s overall precision and marked improvements in MPA and MioU. A comparative analysis of the detection capabilities between the enhanced and original models was conducted, including a pixel count for each category to ascertain the extent of various semantic information. The experimental validation confirms the viability and efficacy of the proposed methodology.
Comparative Study of Rapid Assessment Methods for Earthquake-Triggered Landslides Based on the Newmark Model—A Case Study of the 2022 Luding Ms6.8 Earthquake
Authors: Li Huanyu , Li Dongping , Yin Jingfei , Sun Haiqing , Li Min , Dai Chenbing
Published: August 2024

Earthquake-triggered landslides represent a significant seismic-related disaster, posing threats to both the lives and property of individuals in affected areas. Furthermore, they can result in road and river blockages, as well as other secondary disasters, significantly impacting post-earthquake rescue efforts. Efficient, accurate, and rapid assessment of high-risk landslide zones carries important implications for decision making in disaster response and for mitigating potential secondary disasters. The high-intensity zones VII to IX of the Luding Ms6.8 earthquake on 5 September, 2022, were used as a case study here. Based on the simple Newmark model, the difference method and the cumulative displacement method were employed to assess earthquake-triggered landslides. The assessment results from both methods demonstrated that the areas posing an extremely high risk of earthquake-triggered landslides were predominantly situated on the western side of the Xianshuihe Fault. Verification using actual landslide data showed that both methods had high predictive accuracy, with the difference method slightly outperforming the cumulative displacement method. Moreover, this study recommends determining threshold values for each landslide risk interval having physical meanings using previous data on strong earthquakes when utilizing the difference method to assess the risk of earthquake-triggered landslides.
Influence of Fractal Disc Filter Flow Channel Parameters on Filtration Performance
Authors: Zeng Jiefeng , Yang Peiling , Liu Weijie , Xiang Xudong
Published: August 2024

The research and development of a new disc filter is a key link in intelligent irrigation systems, the core of efficient and water-saving irrigation development, and also an important joint effort to ensure a clean water source in micro-irrigation systems. In this paper, the independent research and development of the fractal flow passage disc filter was taken as the research object, and the disc filter numerical simulation cell (FLUENT) and artificial intelligence technology (Back Propagation Neural Network) were combined to optimize the filter flow channel parameters, including the tilt angle, the length and height of the bottom of the internal section triangle, the taper, the position and number of buffer slots, etc. A new type of disc filter with lower head loss, larger flow capacity, higher filtration efficiency, and longer running time is proposed. It has certain reference value and promotion significance for the future development and design of high-performance disc filters and their wide use.
An Optimization Method for Location-Routing of Cruise Ship Cabin Materials Considering Obstacle Blocking Effects
Authors: Li Jinghua , Huang Wenhao , Wu Xiaoyuan , Dong Ruipu , Lin Pengfei
Published: August 2024

This study examines the challenges related to the storage and distribution of cabin materials on board during the construction of cruise ships. The construction process of cruise ships involves the assembly of various cabin materials, which are temporarily stored and transported in a complex deck environment with multiple obstacles. These processes can be viewed as location-routing problems (LRPs). However, existing solutions for LRPs do not account for the obstacles commonly encountered in deck environments. Therefore, this paper introduces a new variant of LRPs, termed as the BE-LRP (blocking environment location-routing problem). Initially, by considering the optimization objectives of minimizing the distribution distance and the number of vehicles required, the paper develops an optimization model for the location-routing of on-board materials while taking obstacles into consideration. Subsequently, a method for estimating blocked distances is proposed. This method utilizes Gaussian process regression to predict blocked distances and enables the rapid estimation of distances obstructed by obstacles between different destinations. Lastly, a hybrid obstacle blocking distance processing HO-NSGAII algorithm is formulated to address the BE-LRP. Experimental comparisons demonstrate that the distribution scheme derived from this research method does not necessitate modifications to the delivery distance when compared to the traditional NSGAII algorithm, and better aligns with the actual deck conditions. With an equivalent number of delivery vehicles, the scheme results in shorter delivery distances. The delivery distance can be reduced by 3–17% under varying circumstances. These findings are advantageous for enhancing the efficiency of cruise ship construction and mitigating the impact of warehousing and distribution on construction progress.
Numerical Analysis of a Self-Acting Gas Bearing Lubricated with a Low-Boiling-Point Medium Using an Advanced Model Based on the Finite Difference Methods and Universal Computational Fluid Dynamics Software
Authors: Bogulicz Małgorzata , Bagiński Paweł , Żywica Grzegorz
Published: August 2024

Methods for determining the characteristics of self-acting (aerodynamic) gas bearings have been developed for many years, but many researchers and engineers still question how sophisticated a model of such bearings should be to obtain reliable results. This is the subject of this article, which presents a numerical analysis of aerodynamic gas bearings using two alternative methods: a specialized program based on the finite difference method, and a universal CFD program using the finite volume method. Gas bearings with a nominal diameter of 49 mm, designed for a 10 kW turbogenerator operating at a rotational speed of 40,000 rpm, are analyzed. The vapor of the low-boiling medium, designated HFE-7100, is used as the bearing lubricant. The calculations focus on determining the position of the bearing journal where the bearing achieved the required load capacity and checking the bearing characteristics beyond the nominal operating point. The most important results obtained by the two independent methods are compared, and recommendations are made for those interested in the numerical analysis of self-acting gas bearings.
Multi-Objective Real-Time Planning of Evacuation Routes for Underground Mine Fires
Authors: Bi Lin , Liu Yulong , Zhong Deyun , Wen Lixue
Published: August 2024

When a fire occurs underground, pre-existing emergency escape routes may become ineffective. Such scenarios necessitate the real-time planning of escape routes that consider evolving conditions and prioritize safety. This paper proposes a multi-objective real-time search method for emergency escape routes using dynamic programming to address these challenges. Firstly, this paper discusses how the evacuation of an underground mine fire caused by external factors depends on the fire monitoring system, personnel positioning system, and emergency evacuation system, as well as the modeling and solution methods of evacuation route planning. Then, based on fire smoke, CO, and temperature sensor data from the mine ventilation network structure and monitoring system, the possible smoke spread in the event of an underground fire was calculated. The objectives are to optimize both the shortest equivalent length of the path and the shortest time to walk through the smoke flow while ensuring that temporary escape time does not exceed the rated protection time of the self-rescuer. A mathematical model for emergency escape route planning is established under these conditions. A labeling algorithm based on dynamic programming is employed to find the Pareto optimal solution set of emergency evacuation routes that meet emergency requirements. Finally, two path evaluation indicators, namely “escape target priority” and “personnel temporary escape time”, are introduced to re-rank the solutions in the Pareto optimal set, thereby obtaining disaster evacuation routes with different priorities. Example verification shows that the algorithm can quickly solve the disaster evacuation routes that meet the actual disaster evacuation needs in complex networks. Example verification shows that the algorithm can quickly solve the emergency escape routes in complex networks that meet actual emergency escape needs.
Research on the Support Technology for Deep Large-Section Refuge Chambers in Broken Surrounding Rock in a Roadway
Authors: Peng Wenqing , Feng Shenghua
Published: August 2024

The phenomenon of peripheral rock instability is more common in crushed bedrock roadways, and the fundamental reason for this lies in the significantly different characteristics of its peripheral rock stress field. Taking the newly dug belt inclined shaft of PingDingShan TianAn Coal Co., Ltd. No. 6 Mine as the engineering background, a mechanical model of a broken perimeter rock roadway was established by using classical rock mechanics theory. Stress distribution around the roadway of the broken perimeter rock medium was systematically analyzed, and radial and tangential stress formulas of the broken perimeter rock were deduced. Through the formula calculation, it was deduced that there was a stress drop in the intact surrounding rock outside the disturbed zone, and the radial stress of the intact surrounding rock in its deep part was relatively increased, while the tangential stress was relatively decreased. The existence of crushed surrounding rock increased the minimum principal stress and decreased the maximum principal stress of the unfractured surrounding rock, which proves that a well-maintained disturbed zone can play a lining role. Thus, a “U-shaped steel + inverted arch + bottom arch linkage beam + floor bolt compensation” support program was proposed. This joint support program easily forms a closed support structure, which is more effective in controlling the deformation of tunnel perimeter rock. The support structure can effectively resist the deformation of the surrounding rock and enhance bottom drum resistance. Through numerical simulation, it was concluded that the horizontal displacement of the two gangs was reduced by 70%, and the displacement of the top and bottom plates was reduced by 77% after optimization of the support, which effectively controlled the stability of the broken surrounding rock.
Biosimilar Medicines: From Development Process to Marketing Authorization by the EMA and the FDA
Authors: Amaral Carolina , Rodrigues Ana Rita , Veiga Francisco , Bell Victoria
Published: August 2024

Biosimilars are a new category of medicines that have revolutionized the treatment of patients with life-threatening conditions, such as cancer and autoimmune diseases. A biosimilar is a biological product that is very similar to an already approved biological medicine that is used as its reference. These medicines go through less clinical studies than their reference product and therefore the cost of their development process is significantly lower, giving patients access to them more quickly and at a more affordable price. However, due to the structural complexity and inherent degree of variability of these products, it is very difficult to develop biosimilar medicines that are exactly the same as the reference product. Thus, it is extremely important to define strict controls to guarantee that these minor differences are not clinically significant in terms of safety and efficacy. Like any other medicine, biosimilars have to go through a complex approval process, which involves a thorough assessment by regulatory authorities to ensure these products meet the necessary standards of quality, safety, and efficacy before being placed on the market. Due to their nature and complexity, the approval process of biosimilar medicines contains some unique and specific considerations. This review aims to address the regulatory framework of biosimilar medicines, their development process and the approval requirements by the European Medicines Agency (EMA) and the Food and Drug Administration (FDA).
Additive Manufacturing of Ceramic Reference Spheres by Stereolithography (SLA)
Authors: Meana Víctor , Zapico Pablo , Cuesta Eduardo , Giganto Sara , Meana Lorenzo , Martínez-Pellitero Susana
Published: August 2024

Additive Manufacturing (AM) is advancing technologically towards the production of components for high-demand mechanical applications with stringent dimensional accuracy, leveraging metallic and ceramic raw materials. The AM process for ceramic components, known as Ultraviolet Laser Stereolithography (SLA), enables the fabrication of unique parts or small batches without substantial investments in molds and dies, and avoids the problems associated with traditional manufacturing, which involves multiple stages and final machining for precision. This study addresses the need to produce reference elements or targets for metrological applications, including verification, adjustment, or calibration of 3D scanners and mid- to high-range optical sensors. Precision spheres are a primary geometry in this context due to their straightforward mathematical definition, facilitating rapid and accurate error detection in equipment. Our objective is to exploit this novel SLA process along with the advantageous optical properties of technical ceramics (such as being white, matte, lightweight, and corrosion-resistant) to materialize these reference objects. Specifically, this work involves the fabrication of alumina hemispheres using SLA. The manufacturing process incorporates four design variables (wall thickness, support shape, fill type, and orientation) and one manufacturing variable (the arrangement of spheres on the printing tray). To evaluate the impact of the design variables, dimensional and geometric parameters (GD&T), including diameters, form errors, and their distribution on the surface of the sphere, have been characterized. These measurements are conducted with high accuracy using a Coordinate Measuring Machine (CMM). The study also examines the influence of these variables in the dimensional and geometric accuracy of the spheres. Correlations between various parameters were identified, specifically highlighting critical factors affecting process precision, such as the position of the piece on the print tray and the wall thickness value. The smallest diameter errors were recorded at the outermost positions of the tray (rear and front), while the smallest shape errors were found at the central position, in both cases with errors in the range of tens of micrometers. In any case, the smallest deformations were observed with the highest wall thickness (2 mm).
Innovative Energy Sustainable Solutions for Urban Infrastructure: Implementing Micro-Pumped Hydro Storage in Singapore’s Multi-Level Carparks
Authors: Kok Chiang Liang , Ho Chee Kit , Koh Yit Yan , Tay Wan Xuan , Teo Tee Hui
Published: August 2024

As part of the initiative to achieve Singapore’s Green Plan 2030, we propose to investigate the potential of utilizing micro-pumped hydroelectric energy storage (PHES) systems in multi-level carparks (MLCP: a stacked car park that has multiple levels, may be enclosed, and can be an independent building) as a more environmentally friendly alternative to traditional battery storage for a surplus of solar energy. This study focuses on an MLCP with a surface area of 3311 m2 and a height of 12 m, considering design constraints such as a floor load capacity of 5 kN/m2 and the requirement for a consistent energy discharge over a 12 h period. The research identifies a Turgo turbine as the optimal choice, providing a power output of 2.9 kW at a flow rate of 0.03 m3/s with an efficiency of 85%. This system, capable of storing 1655.5 m3 of water, can supply power to 289 light bulbs (each consuming 10 W) for 15.3 h, thus having the capacity to support up to three MLCPs. These results underscore the environmental advantages of PHES over conventional batteries, highlighting its potential for integration with solar panels to decrease carbon emissions. This approach not only aligns with Singapore’s green initiatives but also promotes the development of a more sustainable energy infrastructure.
Use of Lignin, Waste Tire Rubber, and Waste Glass for Soil Stabilization
Authors: Gücek Süleyman , Gürer Cahit , Žlender Bojan , Taciroğlu Murat V. , Korkmaz Burak E. , Gürkan Kürşat , Bračko Tamara , Macuh Borut , Varga Rok , Jelušič Primož
Published: August 2024

The complex interactions between soil and additives such as lignin, glass powder, and rubber tires were investigated using principles of material and soil mechanics. Previous research has mainly focused on individual additives in clay soils. In contrast, this study investigates soil improvement with two different types of waste materials simultaneously. The improvement of soil properties by hybrid waste materials was evaluated using several laboratory tests, including the standard Proctor test, the unconfined compressive strength test, the California Bearing Ratio (CBR) test, and cyclic triaxial tests. The aim of this research is to identify key parameters for the design and construction of road pavements and to demonstrate that improving the subgrade with hybrid waste materials contributes significantly to the sustainability of road construction. The mechanical and physical properties were evaluated in detail to determine the optimal mixtures. The results show that the most effective mixture for the combination of waste glass powder and rubber tires contains 20% glass powder and 3% rubber tires, based on the dry weight of the soil. For the combination of waste glass powder and lignin, the optimum mixture consists of 15% glass powder and 15% lignin, based on the dry weight of the soil. These results provide valuable insights into the sustainable use of waste materials for soil stabilization in road construction projects.
Assistance in Picking Up and Delivering Objects for Individuals with Reduced Mobility Using the TIAGo Robot
Authors: Naranjo-Campos Francisco J. , De Matías-Martínez Ainhoa , Victores Juan G. , Gutiérrez Dueñas José Antonio , Alcaide Almudena , Balaguer Carlos
Published: August 2024

Individuals with reduced mobility, including the growing elderly demographic and those with spinal cord injuries, often face significant challenges in daily activities, leading to a dependence on assistance. To enhance their independence, we propose a robotic system that facilitates greater autonomy. Our approach involves a functional assistive robotic implementation for picking, placing, and delivering containers using the TIAGo mobile manipulator robot. We developed software and routines for detecting containers marked with an ArUco code and manipulating them using the MoveIt library. Subsequently, the robot navigates to specific points of interest within a room to deliver the container to the user or another designated location. This assistance task is commanded through a user interface based on a web application that can be accessed from the personal phones of patients. The functionality of the system was validated through testing. Additionally, a series of user trials were conducted, yielding positive feedback on the performance and the demonstration. Insights gained from user feedback will be incorporated into future improvements to the system.
Experimental and Numerical Analysis of an Innovative Combined String–Cable Bridge
Authors: Beivydas Edmundas , Juozapaitis Algirdas
Published: August 2024

Suspension bridges, such as stress-ribbon, are among the simplest structural bridge systems and have the lowest structural height. The flexibility of these elegant bridges poses great challenges for designers to minimize their deformability under asymmetrical operational loads. Due to the small initial sag, such load-bearing structures also cause significant tensile forces, which requires them to have large cross-sections and massive anchor foundations. This paper analyzes an innovative suspension steel bridge structure combined with a string and a cable. More attention is paid to asymmetric loading as this is more relevant for suspension structures. The new structure is studied numerically and experimentally. It is established that the string stabilizes the displacements of the bridge under asymmetric loading. The stabilization efficiency is proportional to the value of the pre-tension force of the string. The obtained results reveal the behavior of the structure and enable an evaluation of the accuracy of the numerical results, as well as the applied modeling. In addition, the experimentally obtained results allow the evaluation of more aspects of the behavior of the new bridge, which will be useful in further studies of this type of structures.
River Flashiness in Great Britain: A Spatio-Temporal Analysis
Authors: Olin Benjamin , Beevers Lindsay
Published: August 2024

Flashiness refers to the rapidity and frequency of fluctuations in river flow. It can provide insights into flooding, by capturing dramatic increases in river flow, as well as contaminant transport, relating to concentrations of diffuse pollution. Despite a very well gauged river system, there is limited research in Great Britain targeting this component of river flow. This study addresses that gap in knowledge, with a detailed spatio-temporal analysis of river flashiness in Great Britain. Using 513 gauging stations, with historical records of at least 30 years, the average Richards–Baker flashiness index (RBI¯) was calculated for 1990–2020, showing an overall west- (0.6–0.8) to east-coast (0.1–0.2) gradient, being higher in the west (with the exception of some gauges in the south-east). Employing random forest models, the main predictor for flashiness was found to be soil composition, with some additional region-specific predictors. These include flood attenuation by reservoirs and catchment areas, affecting flashiness in the north and west of Great Britain. Additionally, using a subset of 208 gauging stations with data recorded from 1970 to 2020, a temporal analysis examined significant breakpoints and/or trends in yearly flashiness, using the Pettitt test and Mann–Kendall trend test, respectively. Increases in flashiness were found mainly in the north-east and south-west of Great Britain, with implications in flooding and river health. On a seasonal scale, and using a monthly RBI¯, the timing of flashy events was found to oscillate between autumn and spring over the 50 years, gravitating around winter.