bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and validation of high‐performance thin layer chromatographic method for simultaneous quantitation of novel combination perindopril erbumine and moxonidine hydrochloride
Authors: Akabari Ashok H , Surati Jasmina , Patel Sagar , Pathak Bhumin , Patel Arun , Patel Chandani , Patel Sagarkumar K
Published: June 2023

The primary purpose of the present study was to develop and validate a high‐performance thin‐layer chromatography method for quantitatively determining an anti‐hypertensive agent, perindopril erbumine, and moxonidine hydrochloride in bulk and synthetic mixture. The densitometric procedure was performed on aluminum thin‐layer chromatography plates pre‐coated with silica gel 60F254, employing a combination of dichloromethane: toluene: methanol: ammonia (7:1:2:0.1 v/v/v/v) as the mobile phase. The thin‐layer chromatography scanner was operated in absorbance mode at a wavelength of 223 nm to evaluate densitograms. The linearity of the method was established in the range of 1000–5000 ng/band for perindopril erbumine and 40–200 ng/band for moxonidine hydrochloride; the correlation coefficient (r2) was 0.9993 and 0.9983, respectively. The values of a limit of detection (186.06 and 3.51 ng/band, respectively, for perindopril erbumine and moxonidine hydrochloride) and limit of quantification (620.23 and 11.73 ng/band, respectively, for perindopril erbumine and moxonidine hydrochloride) have demonstrated the sensitivity of the developed method. The reported process was precise in both intra‐day and inter‐day analysis; the percentage relative standard deviation of peak area was less than 2% and has an accuracy within 100 ± 2%. The developed method has the potential to quantify perindopril erbumine and moxonidine hydrochloride from its synthetic mixture without any interference from other components or in quality control laboratories.
Multinationals from emerging economies: Strategies, challenges, and the way forward
Authors: Rasheed Abdul A. , Ahmed Zafar U.
Published: June 2023

Multinationals from emerging economies are relatively new players in the global economy. This Special Issue includes five articles that cover several important aspects of the market and nonmarket strategies pursued by emerging market multinational corporations (EMNCs). Given that only a few firms from emerging markets embrace the possibilities and challenges of going global, we highlight the need to examine country, industry, and firm level antecedents of the emergence of EMNCs. We also draw attention to the need to study the role played by immigrant populations in EMNC internationalization.
Goreisan alleviates cerebral edema: Possibility of its involvement in inhibiting aquaporin‐4 function
Authors: Shimizu Tomofumi , Murakami Kazuhito , Matsumoto Chinami , Kido Toshitaka , Isohama Yoichiro
Published: June 2023

Aim

In Japan, goreisan (GRS) is used to alleviate cerebral edema and relieve headaches. Although improvement of water maldistribution in the brain may be one of the mechanisms of action of GRS for cerebral edema and headache, scientific evidence is limited. Here, we aimed to investigate the action mechanism of GRS against cerebral edema and headaches, focusing on water dynamics in the brain.

Methods

We used a well‐established mouse model of cerebral edema to evaluate the effects of GRS on related symptoms and brain water content. The mouse model was subjected to magnetic resonance imaging (MRI) using H217O to assess water dynamics in the brain. The effect of GRS on water permeability through aquaporin‐4 (AQP4) was also examined in vitro.

Results

GRS inhibited the loss of righting reflex and improved survival in the mouse model by ameliorating the increase in brain water content. The MRI evaluation of water dynamics suggested that GRS inhibited water influx into the brain. Evaluation of water permeability via AQP4 in Xenopus laevis oocytes and HEK293 cells showed that GRS inhibited AQP4 function.

Conclusion

GRS suppressed the ubiquity of water in the brain in a mouse model of cerebral edema, suggesting inhibition of AQP4 function (not AQP4 expression) as one of the action mechanisms of GRS. Our findings provide fundamental evidence for the clinical efficacy of GRS against cerebral edema and headaches.
Introduction
Authors: Lambert Laurent A. , Elayah Moosa
Published: June 2023

Twenty years after the terror attacks of 9/11/2001, the world witnessed the humiliating withdrawal of US troops from Afghanistan under the ‘protection’ of the new rulers of Kabul, the Taliban. The introduction to this book sheds light on the background of two decades of ‘War on Terror’ (WoT), a loose umbrella term for many US armed conflicts abroad—some still ongoing—, and reviews major publications on the WoT. It then explains this book’s focus on what has happened in the region to explainwhythe US formidable mobilization of means and might has transformed into such a blatant geostrategic defeat. This is a particularly timely task as we are entering, we argue, the era of a post-American Middle East.
Numerical Simulation on Smoke Control for Extra-Long Tunnel Fires
Authors: Liu Wenbo , Li Junmei , Li Yanfeng
Published: June 2023

Based on an actual project in Beijing, this article investigates the effect of smoke control strategies on smoke extraction efficiency under different fire source locations of the point smoke extraction system in extra-long tunnels using Airpak software. The results show that when a fire occurs in a tunnel, the smoke extraction efficiency of the tunnel smoke extraction system varies greatly depending on the location of the fire source and the adoption of different smoke extraction strategies. Due to the suction of the smoke exhaust shaft fan, the relative distance between the electric smoke exhaust valve and the entrance of the tunnel is close, which will cause the smoke exhaust valve within a certain range to be plug-holing, seriously affecting the smoke exhaust effect of the smoke exhaust system. Smoke exhaust valve beyond this range, although not occurring plug-holing the smoke exhaust efficiency is also relatively low, by changing the opening strategy of the smoke exhaust valve can effectively improve the smoke exhaust valve plug-holing, so as to improve the smoke exhaust efficiency.
Study on Failure Process of Freeze–Thaw Fractured Rock Under Multistage Cyclic Loads
Authors: Peng Liu
Published: June 2023

In order to further study the failure characteristics of freeze-thawed rocks in the alpine region under multistage cyclic loads, a numerical simulation analysis was carried out with RFPA2D software, taking the natural fractured granite from the Beizhan Iron Mine in Hejing County, Xinjiang Province as an example. The results show that the degree of natural fracture determines the fracture form of rock, and when the degree of natural fracture is large, the rock will eventually undergo shear slip failure along the natural fracture. When natural fissure rock is subjected to load, its initial structural deterioration occurs at the fissure, and tensile failure occurs. When the natural fracture expands to a certain extent, the rock begins to undergo large-scale compressive shear failure, which eventually leads to shear-slip failure of the fractured rock. The failure mode of fractured rock is affected by the degree of fracture development, the degree of penetration and the inclination Angle.
Numerical Simulation for the Dynamic Response of Step Topography Subjected to Blasting Load
Authors: Yang Lixiang , Han Yaobin , Zhang Xu , Li Zhiwen
Published: June 2023

The vibration velocity and frequency of rock mass are closely related to the instability and failure of the building. The step topography has great influence on blasting vibration wave propagation. Therefore, it is of great significance to study the dynamic response of step topography subjected to blasting load. In this paper, the FLAC2D program is used to study the dynamic response of step topography subjected to blasting load. The plane strain mode is adopted in the calculation, and the blasting load is assumed to be a triangular pulse wave which is applied to one side of the calculating mode. The amplification effect of the height of the step is first studied. The calculation result shows that the amplification factor increases first and then decreases with the increase of the step height. The maximum value of the amplification factor is consistent with the results of the field test, which indicates the feasibility of the numerical simulation.
Research on Numerical Simulation Analysis and Engineering Application of Prestressed Anchor Cable Construction
Authors: Zhu Yanfang , Xiong Bing
Published: June 2023

The prestressed anchor cable can improve the overall stability of the rock and soil mass of the slope, thereby improving the mechanical properties of the rock and soil mass, and can better control the structural displacement, and achieve the purpose of reducing landslides, dangerous rocks and dangerous rocks. At the same time, the pre-stressed anchor cable construction is convenient, fast in progress, and economical, and has a broad application space. Based on the actual engineering background, this paper analyzes the key technologies in the construction process, and uses finite element software to conduct an overall numerical analysis of the soil after the use of prestressed anchor cables. It analyzes the impact of different slope top loads and finds that for non-prestressed anchor rods, the depth of action is limited, excessively increasing their length will not only cause difficulties in construction, but also have no practical significance. When prestress is applied, the horizontal displacement of the baffle is not uniform under the action of different prestress and slope top load, showing a twisting phenomenon. Along with the increase of the slope top load, the lateral pressure also increases, which causes the displacement of the baffle to decrease with the increase of the slope top load. The research in this paper will have certain guiding significance for the engineering application of prestressed anchor cables.
Study on Fatigue Performance of Typical Fatigue Detail in Orthotropic Steel Deck
Authors: Yan Bing , Zhu Yaoyu , Meng Cheng , Yuanzhou Zhiyuan
Published: June 2023

Orthotropic steel decks (OSDs) are easily subjected to fatigue cracking under the cyclic vehicle loading, and arc notch between diaphragm and U-rib is one of the typical fatigue details. The strain values of three measuring points at arc notch in a steel bridge were monitoring to obtain the stress time histories. Then, fatigue stress amplitudes and fatigue damage degrees were analysed. It was found that this typical fatigue detail was under tension–compression cyclic stress. The maximum stress amplitude appeared at U-rib weld toe, which indicated that fatigue cracks were more prone to propagate on this area, comparison of fatigue damage degrees also corroborated it.
Study on Soil Disturbance Caused by Shield Tunneling in Sandy Strata
Authors: Zou Weiyu , Luo Shuyi , Liu Yingcheng , Pan Hong
Published: June 2023

Shield tunneling and construction in sandy soil have great safety risks, so it is necessary to study the soil disturbance caused by tunneling in sandy soil. However, the law of soil disturbance is still relatively vague, so this paper relies on the actual tunnel project, through high-density, close monitoring; The settlement law of soil around shield tunnel is studied and analyzed. The research shows that the settlement of soil disturbance is basically stable after the shield tail leaves the monitoring section about twice the length of the shield machine; During shield tunneling in sandy strata, the sand on the upper part of the tunnel is very easy to collapse, thus forming a “collapse arch”. The formation of this feature will be one of the reasons for the construction accidents of large diameter shield machines; The remarkable feature of soil disturbance around the tunnel in the water rich sand layer is that the maximum horizontal displacement of the measuring points at different locations occurs at the same depth, and does not develop from the tunnel center to the 45-φ/2 diffusion angle; The maximum horizontal deformation during tunnel construction is far less than the vertical deformation, so the horizontal displacement can be used to better analyze the actual impact of shield construction disturbance.
DSM Based Optimization to the Design Process of Prefabricated Construction
Authors: Yang Xinlong
Published: June 2023

The linear way of prefabricated construction (PC) design can induce extensive occurrence of reworks and increase costs and worktime. To optimize a reasonable and concurrent PC design workflow, a system of detailed PC design processes was built based on literature review and expert investigation. Based on graphic theory and DSM, the interdependent relationships between the processes were confirmed, and clusters of the coupled processes were identified. The paper proposed a model with an improved genetic algorithm to optimize the workflow to reduce rework costs and worktime. Then, a case study is used to estimate the model. The result shows that the optimization can reduce 12% costs and 12.43% worktime, and suggests that the cooperation between work of different design stages needs to be strengthened for a better product and less resource usage. The proposed model can effectively reduce the impact of rework. It improves the optimization methods of PC processes, and is valuable to PC planning and control.
Research on Vibration Signal Characteristics of Multilateral Boundary Deep Hole Blasting
Authors: Chen Junkai , Hao Xiangjun , Wei Zheng , Gao Wenxue , Zhang Xiaojun , Liu Zhaochen
Published: June 2023

The essence of blasting action is the interaction between explosive energy and medium, and the blasting effect depends on the characteristics of explosive energy, medium and interaction law. The multi-boundary comprehensive blasting theory of stonework establishes the functional relationship among boundary conditions, throwing rate and explosive quantity. In this paper, a formula for calculating the explosive charge of multi-boundary deep-hole blasting is put forward, and the experimental study is carried out based on HHT analysis technology. Research shows that: (1) Based on HHT analysis technology, the main frequency of blasting vibration signal energy is in 0–40 Hz, and mainly in low frequency band, while the energy contained in high frequency component gradually decays. (2) Multi-boundary deep-hole controlled blasting has evenly broken rock blocks and all collapsed within the design range, which has achieved good blasting effect.
Study on Design and Application of Ultra-Thin Cover for Noise Reduction and Skid Resistance of Old Cement Concrete Pavement
Authors: Huang Hui , Chen Jie , Zhang Honggang
Published: June 2023

According to the comparative analysis from the whole life cycle economic cost accounting, the capital investment of preventive maintenance of old cement concrete pavement is less than that of corrective maintenance. Based on the old cement concrete pavement, the problem such as anti-sliding noise, from how to improve the driving comfort and improve the stress of the cement road panel considering structure of old cement concrete pavement preventive maintenance are discussed in this paper, recommend a kind of cement concrete pavement noise reduction against sliding type ultra-thin rubber asphalt surface preventive maintenance structure, It can provide favorable technical reference for the applicability and rational selection of preventive maintenance structure of old cement concrete pavement.
Influence of Anti-Mud Agent on the Performance of Gangue Backfilling Paste
Authors: Zhou Wei , Guo Zhaoyang , Wang Kangkang , Zhang Haibo , Guan Xuemao
Published: June 2023

Anti-mud agents could improve the efficiency of the action of water reducers in concrete by preferentially. The anti-mud agent was preferentially adsorbed on the clay surface, which reduces the ineffective adsorption of the water reducing agent to the paste, thereby improving the water reduction efficiency. However, its application in high-sediment content coal gangue gypsum backfill materials had not been reported. In this paper, The competitive adsorption mechanism echanism of anti-mud agent was first described. Tested its competitive adsorption with water reducer molecules on the surface of gangue powder. The influences of anti-mud agent on the slump, coagulation time and compressive strength of the paste at different ages were studied. The results showed that: as the dosage of anti-mud agent increased, the amount of desorption of the water reducer from the surface of gangue powder increased. When adding the same extra amount of water reducer, the slump of the backfill paste material increased with prolonged the coagulation time. The strength of the paste decreased at 3 d, and the strengths of 7 d and 28 d were not significantly deteriorated. A small amount of anti-mud agent could greatly improve the fluidity of the paste. This study provides a scientific basis for the pumping of pure solid waste paste.
Research and Application of Anchorage Vertical Loading System in Building Reinforcement and Rectification
Authors: Li Zhao , Sun Xunhai , Jia Ning , Zhou Shengbin , Yang Xinhui , Tong Jianxing , Yang Haitao
Published: June 2023

In this paper, the settlement and tilt of a building in north China are taken as an example. The differential settlement of the building is not stable, and the tilt continues to increase. After the rectification measures of forced landing by digging out the soil were taken, the expected effect was not achieved. Then the auxiliary rectification was carried out by means of centralized and cyclic loading through the anchorage vertical loading system, and the automatic dipmeter and manual monitoring are adopted in the process of deviation rectification to achieve information construction. At present, the construction of this project has been completed and the effect of reinforcement and rectification is good, which can provide reference for similar projects and has certain promotion and guidance significance.
Stability Analysis of Earth and Rock Dams During the Construction Period of Soft Foundation Reinforcement
Authors: Li Jiahao , Xu Jingnan , Zhao Shiwen , Wu Junhua
Published: June 2023

The consolidation of earth and rock dam foundations and its effect on stability is a key concern in water conservancy and water transportation projects. It is common to use the vacuum combined pre-pressure method to deal with soft ground foundation, where the reasonable selection of soil consolidation coefficient is one of the important factors to determine the success of the project. In this paper, numerical simulation is used to study the strength law of soil and rock dam foundation under different consolidation coefficients of soft ground, and the corresponding stability coefficients of soil and rock dam are obtained. On this basis, the reinforcement effect of an additional counter pressure platform is proposed and analyzed. The results show that the larger the consolidation coefficient of soft ground is, the more it is conducive to the growth of the strength of the soft soil layer and can effectively improve the stability coefficient of the earth and rock dam. At the same time, the additional counter-pressure platform has a certain effect on the overall stability enhancement of the earth and rock dam. The research results can provide a reference for the application of vacuum combined pre-pressure method to earth and rock dam projects.
Seepage Analysis of Drainage Decompression in Sloping Basement
Authors: Li Shuijiang , Wan Quanbin , Yan Haorong , Pan Hong
Published: June 2023

The accidents of bottom floor cracking occur on underground structure due to uplift pressure. Especially in the southern rainy area, super large buildings on slope with high underground water level are in a complex seepage field and it is hard to deal with. In order to solve this problem, a residential district in Guangzhou as an example is analyzed through multiple stratigraphic level of 2D finite element method to the most dangerous conditions of the seepage field. The more reasonable and economic drainage decompression measures, " relief well + sand cushion", are put forward, which can meet the requirement of decompression. Finally, the monitoring data further validate the rationality of the method.
Effect of Autoclaved Aerated Concrete on Dynamic Response of Concrete Gravity Dam Under Earthquakes
Authors: Zhao Fei , Zhao Shaoyu , Fan Shuli
Published: June 2023

Autoclaved Aerated Concrete (AAC) is commonly used in lower floors buildings in low seismicity areas due to its lightweight property and high energy absorption capacity. This paper proposes a novel application of AAC as an effective seismic countermeasure in the reduction of vibrational energy for concrete gravity dam. According the vibrating characteristics and failure modes of gravity dam under earthquake excitation, AAC was placed in the upper zone of a gravity dam to reduce the seismic inertia force and consequently to increase the seismic safety of the dam. Dynamic responses of two non-overflow sections of a gravity dam were analyzed through finite element analysis utilizing a damaged plasticity constitutive model. The anti-seismic effect of using AAC in gravity dams is researched by inputting different kind of ground motion records. The comparison of the natural vibration characteristics, dam crest displacement, and dynamic damage of the dam were investigated. The results show that, AAC effectively improves seismic resistance of concrete gravity dams, particularly eliminating cracks in the concrete along reduced damage zones, through inertial force reduction and energy dissipation. The results warrant further considerations for applying AAC to gravity dams.
Application and Numerical Simulation of Key Technologies for Deep Foundation Pit Support
Authors: Tong Jingsheng , Zhang Hongmei , Zhang Weiqiang
Published: June 2023

This paper adopts the key technology “tunnel and underground space support components”, assembles it into a “honeycomb” structure type, and expands its application to deep foundation pit support engineering, which fully reflects the combination of “industry-university-research” theoretical research and engineering practical application. This key technology of support can optimize the setting of lateral support components in the deep foundation pit support process, optimize and improve the current conventional deep foundation pit support construction technology, and has good research and industrialization promotion and application value. In this paper, the deformation and stress–strain analysis of each working condition of excavation of the foundation pit are also carried out through numerical simulation, and the uplift displacement and stress change of the foundation pit bottom are within the safety range of stress control, and the supporting stress is far lower than the bearing capacity of the prefabricated components, which further verifies the practicability and reliability of the key innovative technology.
The Effect of Replacing Natural Aggregate with Geopolymer Artificial Aggregates on Air Voids of Hot Mix Asphalt
Authors: Karyawan I Dewa Made Alit , Ekaputri Januarti Jaya , Widyatmoko Iswandaru , Ahyudanari Ervina
Published: June 2023

High voids in hot mix asphalt (HMA) can increase sensitivity to moisture, resulting in premature failure of asphalt pavements. The use of artificial aggregates as a substitute for natural aggregates has been considered in this paper to optimize air voids that meet the requirements. The reason is that natural aggregates are non-renewable raw materials and their availability continues to decrease. This study aims to determine the effect of replacing some natural aggregates with artificial aggregates on air voids. This experiment assessed 2 sets of HMA standard gradations, namely the Bina Marga standard (Indonesian standard) and the Federal Aviation Administration (FAA) standard. For each set, 2 different raw materials are used, namely: 1) asphalt mixture using 100% natural aggregate and 2) asphalt mixture using a combination of 25% artificial aggregate and 75% natural aggregate. The analysis includes volumetric mixes, such as VIM (voids in mix), VMA (voids in mineral aggregates), and VFA (bitumen filled voids). The results of the analysis found that the replacement of natural aggregates with artificial aggregates affected the cavities formed in the asphalt mixture. HMA that uses natural aggregates, shows VMA, VFA and VIM that meet the requirements for pavement surface materials.
Finite Element Analysis of Reinforced Hollow High-Strength Concrete Filled Square Steel Tubular Middle-long Column under Eccentric Load
Authors: Yang Zhijian , Li Jixing , Li Guochang , Cui Weizhe
Published: June 2023

Traditional hollow concrete filled steel tube components are mainly used in the transformer power structure. In order to improve the mechanical properties and application scope of hollow concrete filled steel tube components, a new type of reinforcement hollow steel tube high-strength concrete combination structure is proposed. Given that the components in the construction system are frequently in an eccentric stress condition throughout the structural system, the finite element analysis program ABAQUS produces 20 eccentric compression middle-long column models. The overall force process of the composite members is investigated, and parametric analysis is done on the yield strength, eccentricity, steel content, and various lengths to slenderness ratios of the various steel components. According to the results of finite element analysis, the stress process of reinforced hollow high strength concrete filled square
steel tube components is mainly divided into four stages: elastic section, elastic–plastic section, plastic strengthening section and descending stage. The configuration of steel bars in the composite components can significantly improve the ductility of the composite components. This new combination structure can be used as a wind-resistant column in industrial plants in the future, which has certain application prospects and economic benefits.
Effect of Cross-Section Shape on RC Specimen’s Behavior Under Asymmetrical Impact Loading
Authors: Al-Bukhaiti Khalil , Yanhui Liu , Shichun Zhao , Daguang Han , Abas Hussein
Published: June 2023

By applying asymmetrical lateral impact forces on RC specimens, the specimens’ cross-sectional shape is analyzed. The effectiveness of the RC specimens’ resistance to impact was examined using a drop hammer. Performing research on the factors that led to the failure of various RC specimen shapes and the dynamic responses they exhibited. In the experiment, eight circular and square specimens were used. Includes the method of failure, the impact force, and the deflection time history. The findings point to shear fractures between the point of impact and the adjacent support. The right side of the impact point has suffered significant damage, and the shear tests on all specimens failed. The peak impact force that square specimens can bear may be greater than circular ones. Protecting the concrete core and reducing maximum deflection are benefits of using a square specimen. When the ratio of stirrups is raised, there is only a little variation in the square specimen’s damage range. This may cause a slight reduction in damage, but it is not significant. The plateau force of a circular specimen can be increased, but only a little. An increase in the stirrup ratio may increase energy use.
Energy Spatial Distribution of Structure Noise Radiated from U-beam Slabs
Authors: Zhou Li , Zhang Tianqi , Luo Yanyun
Published: June 2023

At present, the application of U-beams in urban rail transit is gradually increasing, but researches about the bridge structural noise are still insufficient. This article took U-type girder as the research object and studied the structural noise distribution on the basis of energies in different frequency band. Firstly, the dynamic response of the bridge under vehicle load was acquired with the combination of finite element simulation method and field test. Secondly, the structure-acoustic coupling finite element-infinite element model of the U-beam was established, and noise fields of the whole U-beam, the floor and the wing slabs were calculated respectively. By calculating the energies contribution of the sound field point in different frequency bands, the spatial distribution of the radiation noise of the floor and the wing slab in the above frequency bands were obtained. The results show that in the frequency range of 20–200 Hz and the main frequency band (40– 63 Hz), the floor plays a major role in most areas of the whole noise field, and the main influence domain of wing slabs is located in the sector area around wing slabs. In the frequency range of 100–160 Hz, the floor mainly contributes to the acoustic energy of the sector region above and below the U-beam.
Cases Study on Foundation Pit Design in Complex Environment of Urban Core Area
Authors: Ma Lili , Chen Yun , Zhang Liang , Zhao Gaigai , Xia Fei , Yang Qinfeng , Zhao Zhiyuan
Published: June 2023

With the degree of urban underground space developing in China, the scale and excavation depth of foundation pit is much larger, and the surrounding environment is also more and more complex. Therefore, five cases of foundation pit design in complex environment have been studied in this paper. Then combined with local engineering experience, a design scheme of foundation pit adjacent to important facilities which is suitable for Qianjiang New Town has been summarized. Finally, based on the five cases, a simple model to assessment the complexity of the surrounding environment is proposed.
Use of Electrical Resistivity Tomography (ERT) for Detecting Underground Voids on Electrical Pylon Installation Sites: Case Studies from Labé Prefecture, Republic of Guinea
Authors: Konaté Ahmed Amara , Kaba Oumar Barou , Conté Mohamed Samuel Moriah , Zaheer Muhammad , Thiam Baye Mbaye , Oularé Fassidy , Diallo Moussa
Published: June 2023

This study was carried out within the framework of the Gambia River Basin Development Organization Energy Project (OMVG), which brings together Gambia, Guinea, Guinea-Bissau and Senegal. The construction of a high voltage interconnection network fed by a hydro-electricity power station to supply power to OMVG member states must be done on stable ground. During the construction of the installation pits for the pylons in Labé Prefecture, cavities in the geological formations were discovered on the initial planned route. Regarding to geotechnical context of subsurface cavities risk it is mandatory to know their exact location in study areas to reduce the potential degree of risk. A field study was conducted to investigate the lithology, as well as in detecting the presence of apparent faults. Geophysical data was collected using Two Dimensional ERT with different electrode spacing to delineate associated subsurface cavities on each site and each cavity respectively. The target depth was 20 m. The result shows that the observed cavities were because of the dissolution of certain minerals constituting the weathering crust due to the infiltration and the seasonal variation in the level of the watercourses. The cavities were almost entirely empty such as in the cases of pylons 213 and 210 indicated that the weathering crust is due to the groundwater infiltration and the seasonal variations in the river flow level. The finding of this study showed that the ERT method have a good applicability in the detection of underground cavities in the study area.
Detailed Analysis of Shrinkage and Creep Effect of Concrete in Prestressed Box Girder Bridge
Authors: Tan Donglian , Ding Wenyuan , Zhao Yue , Yan Chuqin
Published: June 2023

For a 60 m prestressed concrete box girder bridge using structural analysis software as ANSYS and MIDAS/civil, combined with several creep prediction models, a reasonable creep prediction model has been obtained. Considering the influence of prestressed tendon relaxation on the shrinkage and creep of concrete, a refined finite element model is established for numerical analysis and compared with the experimental data. The comparison results show that the calculated value of the refined finite element model with reasonable prediction models and considering the effect of prestress relaxation is closer to the measured value. Finally, the finite element model of solid elements considering the effect of prestress relaxation with the GL2000 creep prediction model is used to analyze the shrinkage and creep effect of a prestressed concrete continuous rigid frame bridge.
On the decoherence of primordial gravitons
Authors: Ning Sirui , Sou Chon Man , Wang Yi
Published: June 2023

Abstract

It is well-known that the primordial scalar curvature and tensor perturbations, ζ and γij, are conserved on super-horizon scales in minimal inflation models. However, their wave functional has a rapidly oscillating phase which is slow-roll unsuppressed, as can be seen either from boundary (total-derivative) terms of cosmological perturbations, or the WKB approximation of the Wheeler-DeWitt equation. Such an oscillatory phase involves gravitational non-linearity between scalar and tensor perturbations. By tracing out unobserved modes, the oscillatory phase causes faster decoherence of primordial gravitons compared to those by bulk interactions. Our results put a stronger lower bound of decoherence effect to the recent proposals probing squeezed primordial gravitons.
Technology‐assisted anterior cruciate ligament reconstruction improves tunnel placement but leads to no change in clinical outcomes: a systematic review and meta‐analysis
Authors: Yavari Ehsan , Moosa Sabreena , Cohen Dan , Cantu‐Morales David , Nagai Kanto , Hoshino Yuichi , de SA Darren
Published: June 2023

Purpose

To investigate the effect of technology‐assisted Anterior Cruciate Ligament Reconstruction (ACLR) on post‐operative clinical outcomes and tunnel placement compared to conventional arthroscopic ACLR.

Methods

CENTRAL, MEDLINE, and Embase were searched from January 2000 to November 17, 2022. Articles were included if there was intraoperative use of computer‐assisted navigation, robotics, diagnostic imaging, computer simulations, or 3D printing (3DP). Two reviewers searched, screened, and evaluated the included studies for data quality. Data were abstracted using descriptive statistics and pooled using relative risk ratios (RR) or mean differences (MD), both with 95% confidence intervals (CI), where appropriate.

Results

Eleven studies were included with total 775 patients and majority male participants (70.7%). Ages ranged from 14 to 54 years (391 patients) and follow‐up ranged from 12 to 60 months (775 patients). Subjective International Knee Documentation Committee (IKDC) scores increased in the technology‐assisted surgery group (473 patients; P = 0.02; MD 1.97, 95% CI 0.27 to 3.66). There was no difference in objective IKDC scores (447 patients; RR 1.02, 95% CI 0.98 to 1.06), Lysholm scores (199 patients; MD 1.14, 95% CI − 1.03 to 3.30) or negative pivot‐shift tests (278 patients; RR 1.07, 95% CI 0.97 to 1.18) between the two groups. When using technology‐assisted surgery, 6 (351 patients) of 8 (451 patients) studies reported more accurate femoral tunnel placement and 6 (321 patients) of 10 (561 patients) studies reported more accurate tibial tunnel placement in at least one measure. One study (209 patients) demonstrated a significant increase in cost associated with use of computer‐assisted navigation (mean 1158€) versus conventional surgery (mean 704€). Of the two studies using 3DP templates, production costs ranging from $10 to $42 USD were cited. There was no difference in adverse events between the two groups.

Conclusion

Clinical outcomes do not differ between technology‐assisted surgery and conventional surgery. Computer‐assisted navigation is more expensive and time consuming while 3DP is inexpensive and does not lead to greater operating times. ACLR tunnels can be more accurately located in radiologically ideal places by using technology, but anatomic placement is still undetermined because of variability and inaccuracy of the evaluation systems utilized.

Level of evidence

Level III.
Language proficiency of migrants: the relation with job satisfaction and skill matching
Authors: Bloemen Hans G.
Published: June 2023

We empirically analyse the relation between language proficiency and job level of migrants in the Netherlands. A lack of language skills may induce the migrant to work in jobs of a lower level leading to lower job satisfaction. We analyse information about job satisfaction, the fit between the migrant’s education and skill level and the job, and professional level. Men with a higher proficiency level are more satisfied with their type of work and are employed at a higher professional level. For women, no impact of language proficiency can be found.
Does classification of green aid flows matter for environmental quality?
Authors: Apergis Nicholas , Pinar Mehmet , Unlu Emre
Published: June 2023

Climate change imposes an existential threat on the globe and has already had sizeable economic costs to countries. Environmental aid flows aim to alleviate the rising concerns of climate change in the developing world. Even though the existing literature has examined the effectiveness of green aid flows for reducing carbon dioxide emissions in the recipient countries, no existing study has examined the effectiveness of different classifications of green aid. Examining the green aid flows to 97 developing countries between 2002 and 2018, we find that all types of green aid significantly reduce carbon dioxide emissions; however, the aid flows targeting the environmental objectives are more effective in reducing carbon dioxide emissions compared to the aid flows that do not target environmental objectives or are not screened. The findings highlight that more aid should be screened and targeted for environmental objectives to increase the effectiveness of green aid flows in developing countries.
Hopf Bifurcations of Moore-Greitzer PDE Model with Additive Noise
Authors: Meng Yiming , Namachchivaya N. Sri , Perkowski Nicolas
Published: June 2023

The Moore-Greitzer partial differential equation (PDE) is a commonly used mathematical model for capturing flow and pressure changes in axial-flow jet engine compressors. Determined by compressor geometry, the deterministic model is characterized by three types of Hopf bifurcations as the throttle coefficient decreases, namely surge (mean flow oscillations), stall (inlet flow disturbances) or a combination of both. Instabilities place fundamental limits on jet-engine operating range and thus limit the design space. In contrast to the deterministic PDEs, the Hopf bifurcation in stochastic PDEs is not well understood. The goal of this particular work is to rigorously develop low-dimensional approximations using a multiscale analysis approach near the deterministic stall bifurcation points in the presence of additive noise acting on the fast modes. We also show that the reduced-dimensional approximations (SDEs) contain multiplicative noise. Instability margins in the presence of uncertainties can be thus approximated, which will eventually lead to lighter and more efficient jet engine design.
Data-Driven Reduced Order Models Using Invariant Foliations, Manifolds and Autoencoders
Authors: Szalai Robert
Published: June 2023

This paper explores how to identify a reduced order model (ROM) from a physical system. A ROM captures an invariant subset of the observed dynamics. We find that there are four ways a physical system can be related to a mathematical model: invariant foliations, invariant manifolds, autoencoders and equation-free models. Identification of invariant manifolds and equation-free models require closed-loop manipulation of the system. Invariant foliations and autoencoders can also use off-line data. Only invariant foliations and invariant manifolds can identify ROMs, and the rest identify complete models. Therefore, the common case of identifying a ROM from existing data can only be achieved using invariant foliations. Finding an invariant foliation requires approximating high-dimensional functions. For function approximation, we use polynomials with compressed tensor coefficients, whose complexity increases linearly with increasing dimensions. An invariant manifold can also be found as the fixed leaf of a foliation. This only requires us to resolve the foliation in a small neighbourhood of the invariant manifold, which greatly simplifies the process. Combining an invariant foliation with the corresponding invariant manifold provides an accurate ROM. We analyse the ROM in case of a focus type equilibrium, typical in mechanical systems. The nonlinear coordinate system defined by the invariant foliation or the invariant manifold distorts instantaneous frequencies and damping ratios, which we correct. Through examples we illustrate the calculation of invariant foliations and manifolds and at the same time show that Koopman eigenfunctions and autoencoders fail to capture accurate ROMs under the same conditions.
Lattice-Boltzmann LES modelling of a full-scale, biogas-mixed anaerobic digester
Authors: Dapelo Davide , Kummerländer Adrian , Krause Mathias J. , Bridgeman John
Published: June 2023

An Euler–Lagrange multicomponent, non-Newtonian Lattice-Boltzmann method is applied for the first time to model a full-scale gas-mixed anaerobic digester for wastewater treatment. Rheology is modelled through a power-law model and, for the first time in gas-mixed anaerobic digestion modelling, turbulence is modelled through a Smagorinsky Large Eddy Simulation model. The hydrodynamics of the digester is studied by analysing flow and viscosity patterns, and assessing the degree of mixing through the Uniformity Index method. Results show independence from the grid size and the number of Lagrangian substeps employed for the Lagrangian sub-grid simulation model. Flow patterns are shown to depend mildly on the choice of bubble size, but not the asymptotic degree of mixing. Numerical runs of the model are compared to previous results in the literature, from a second-ordered Finite-Volume Method approach, and demonstrate an improvement, compared to literature data, of 1000-fold computational efficiency, massive parallelizability and much finer attainable spatial resolution. Whilst previous research concluded that the application of LES to full-scale anaerobic digestion mixing is unfeasible because of high computational expense, the increase in computational efficiency demonstrated here, now makes LES a feasible option to industries and consultancies.
Risk of visual axis opacification in infants with and without primary IOL implantation after congenital cataract surgery performed during the first 4 months of age
Authors: Hložánek Martin , Cilečková Lenka , Alió Jorge L. , Autrata Rudolf , Zelenayová Nina , Komínek Martin , Cendelín Jiří , Mahelková Gabriela
Published: June 2023

Purpose

The study evaluates the rate of postoperative formation of a pupillary membrane (PM) and posterior visual axis opacification (PVAO) in infants with and without primary IOL implantation during the first 4 months of infancy.

Methods

Medical records for 144 eyes (101 infants) operated between 2005 and 2014 were evaluated. A posterior capsulectomy and anterior vitrectomy were performed. Primary IOL implantation was performed in 68 eyes, while 76 eyes were left aphakic. There were 16 bilateral cases in the pseudophakic group and 27 in the aphakic group. The follow-up period was 54.3 ± 21.05 months and 49.1 ± 18.60 months, respectively. Fisher’s exact test was used for statistical analysis. The two-sample t-test with equal variance was used to compare surgery age, follow-up period and time intervals of complications.

Results

The mean age of surgery was 2.1 ± 0.85 months in the pseudophakic and 2.2 ± 1.01 months in the aphakic group. PM was diagnosed in 40% pseudophakic and 7% aphakic eyes. A second surgery for PVAO was performed in 72% pseudophakic and 16% aphakic eyes. Both were significantly higher in the pseudophakic group. In the pseudophakic group, the number of PVAO was significantly higher in infants operated before 8 weeks of age compared to surgery age 9–16 weeks. The frequency of PM was not age-dependent.

Conclusion

Although it remains feasible to implant an IOL during the primary surgery, even in very young infants, there should always be solid arguments for this decision since it puts the child at higher risk of repeated surgeries under general anaesthesia.
Dehydrogenation of dicyclohexylamine in gaseous phase over a nickel catalyst: effect of reaction parameters
Authors: Valeš Roman , Krupka Jiří
Published: June 2023

This work deals with a study of the effect of reaction temperature and partial pressure of hydrogen on the product selectivity of the gas-phase dehydrogenation of dicyclohexylamine. Laboratory experiments of dicyclohexylamine dehydrogenation were performed in a glass tubular flow-through reactor with the use of commercial supported nickel Ni/Cr2O3-SiO2 catalyst. The systematic variation in reaction temperature (433–463 K) and partial pressure of hydrogen, i.e. the molar ratio of dicyclohexylamine to H2 and N2 (1:0:30–1:15:0), was used to investigate the dehydrogenation of dicyclohexylamine from the perspective of the formation of products. It was confirmed that the major products of dicyclohexylamine dehydrogenation are imine N-cyclohexylidenecyclohexanamine and aromatic amine N-phenylcyclohexylamine, while the latter is the dominant product. The sequential hydrogenolysis reaction of N-phenylcyclohexylamine was observed to result in the formation of cyclohexylamine and benzene. Furthermore, a significant increase in the concentration of the other six products was observed. The mass spectrometry detection identified these products as N-butylcyclohexanamine, N-pentylcyclohexanamine, N-isopentylcyclohexanamine, N-(2-methylbutyl)cyclohexanamine, N-cyclopentylcyclohexanamine, and N-(3-methylcyclopentyl)cyclohexanamine. The reaction results in the formation of two dehydrogenation products, which are accompanied by other subsequent reactions, such as hydrogenolysis, isomerization, and cyclization.

Graphical abstract
Vestibuloplasty and its impact on the long-term survival and success of dental implants in irradiated and non-irradiated patients after head and neck tumor therapy: a retrospective study
Authors: Wüster Jonas , Sachse Claudia , Sachse Christian , Rendenbach Carsten , Wagendorf Oliver , Vach Kirstin , Preissner Saskia , Heiland Max , Nelson Katja , Nahles Susanne
Published: June 2023

Objectives

This study aimed to evaluate the influence of vestibuloplasty on the clinical success and survival of dental implants in head and neck tumor patients.

Materials and methods

A retrospective single-center study was conducted. All patients received surgical therapy of a tumor in the head or neck and underwent surgical therapy and, if necessary, radiotherapy/radiochemotherapy. Patients with compromised soft tissue conditions received vestibuloplasty using a split thickness skin graft and an implant-retained splint. Implant survival and success and the influence of vestibuloplasty, gender, radiotherapy, and localizations were evaluated.

Results

A total of 247 dental implants in 49 patients (18 women and 31 men; mean age of 63.6 years) were evaluated. During the observation period, 6 implants were lost. The cumulative survival rate was 99.1% after 1 year and 3 years and 93.1% after 5 years for patients without vestibuloplasty, compared to a survival and success rate of 100% after 5 years in patients with vestibuloplasty. Additionally, patients with vestibuloplasty showed significantly lower peri-implant bone resorption rates after 5 years (mesial: p = 0.003; distal: p = 0.001).

Conclusion

This study demonstrates a high cumulative survival and success rate of dental implants after 5 years in head and neck tumor patients, irrespective of irradiation. Patients with vestibuloplasty showed a significantly higher rate of implant survival and significantly lower peri-implant bone resorption after 5 years.

Clinical relevance

Vestibuloplasty should always be considered and applied if required by the anatomical situations to achieve high implant survival/success rates in head and neck tumor patients.