Article
Construction & Building Technology
Andrea Carigi, Simone Saltarin, Alfio Di Giovanni, Carmine Todaro, Daniele Peila
Summary: This paper presents a comparative test campaign between concrete produced with clean aggregate and aggregate treated with surfactants. The results show that the presence of surfactants significantly reduces the compressive strength (up to 41 %), the elastic moduli (up to 25 %), and the specific weight (up to 7 %) of the concrete.
CASE STUDIES IN CONSTRUCTION MATERIALS
(2023)
Article
Engineering, Geological
Kyungtae Kim, Mokhtar A. Khalifa, M. Hesham El Naggar, Ahmed Elgamal
Summary: A series of large-scale shake table tests were conducted to evaluate the seismic behavior of a U-shaped spillway retaining wall. Different backfill conditions and earthquake records were utilized to assess the seismic response. The test results showed that wall deflection and bending moment increased with PGA amplitude, and the seismic demands were generally lower up to a PGA of about 0.8 g. Two-dimensional finite element analyses provided reasonable agreement with experimental data.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2023)
Article
Multidisciplinary Sciences
Jakub Sikorski, Witold Pawlowski
Summary: This article presents the results of a study on resistance to motion in a multi-stage planetary transmission, as well as the operational performance tests conducted. By lowering the temperature, the applicability of the transmission device in extraterrestrial conditions can be further validated.
SCIENTIFIC REPORTS
(2022)
Article
Metallurgy & Metallurgical Engineering
Masatoshi Takano, Satoshi Asano, Masahiro Goto
Summary: The recycling of nickel, cobalt and rare earths from spent nickel-metal-hydride batteries was investigated. Nickel and cobalt were recovered as a nickel-cobalt mixed sulfide, which can be used as an intermediate raw material in existing nickel refineries. Rare earths were recovered as double sulfates, which can be recycled into industrial materials. The study showed that yttrium, a heavy rare earth, could be recovered by coprecipitation with a light rare-earth double sulfate, even though such precipitation was considered impossible due to the high solubility of yttrium double sulfate. The optimal conditions for leaching, double-sulfate precipitation, and sulfide precipitation reactions were determined in laboratory tests and successfully demonstrated in pilot tests. The estimated metal yields were high, with 87% nickel, 90% cobalt, 54% yttrium, 99% lanthanum, and 99% cerium. The impurities in the recovered materials were low, demonstrating the high separation performance of this process.
Article
Engineering, Civil
Peng Yu, Changhai Zhai, Jin Liu, Xiaoting Wang
Summary: The study focuses on the seismic performance of desktop medical laboratory equipment and the effectiveness of restrainers in response mitigation. Shaking table tests are conducted to investigate the damage states and fragilities of these equipment under different conditions, such as being placed against a wall. The results show that higher input peak acceleration leads to larger component peak acceleration and residual displacement, and the wall can limit rocking through energy dissipation. The restrainers effectively mitigate displacement but increase acceleration, improving the seismic performance of the equipment.
Article
Construction & Building Technology
Shuchen Li, Zeen Wan, Shisen Zhao, Pengfei Ma, Manling Wang, Bin Xiong
Summary: During earth pressure balance (EPB) shield tunneling in a sandy stratum, the problem of spewing and incomplete soil discharge often occurs. By using soil conditioning agents, the excavated soil can be modified to have flow plasticity. Laboratory and performance tests were conducted to evaluate conditioned sandy soil and conditioning agents from Nanchang Metro Line 4. The study found that increasing the concentration of foam agent led to higher foam expansion rate (FER) and half-life time (H-T) up to a critical concentration of 5%. The presence of a high molecular weight polymer inhibited the FER and H-T of the foam. However, when the volume ratio (VR) of the polymer and foam agent exceeded 0.3, the polymer increased the viscosity of the foam agent solution, which reduced foam drainage rate and increased foam stability. The polymer also reduced soil permeability, which was the most significant effect. A properly conditioned sand, with good flow plasticity and low rotational torque and SD, was achieved when the foam expansion rate (FIR) was 40%, VR was 0.1, and soil infiltration rate (SIR) was 30%. The engineering application of this soil conditioning scheme, based on laboratory test results, ensured the smooth completion of the tunnel.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2022)
Article
Engineering, Geological
Sara Rios, Maxim Millen, Julieth Quintero, Antonio Viana da Fonseca
Summary: The damage caused by earthquakes can be a result of seismic excitation and/or excess pore pressure in the soil. Reduction in soil stiffness due to decreased effective stress affects the seismic response of the soil. Therefore, the level of damage depends on the amount of seismic energy before liquefaction. Developing simplified methods to assess excess pore pressure is crucial for estimating seismic demand and improving building safety.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
L'ubomir Hujo, Juraj Jablonicky, Juraj Tulik, Jan Kosiba, Jerzy Kaszkowiak, Matej Michalides
Summary: Through simulating operating conditions, the performance of motor vehicle oil filters and designed equipment can be evaluated. Findings can be used to design new filter materials and extend replacement intervals with a suitable methodology, leading to important economic and ecological benefits.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Geological
B. X. Fang, S. H. Liu, Y. Lu, S. Chen, Y. G. Zhang, C. C. Zhang, C. B. Zhang
Summary: Soilbag cushion is a promising base isolation method that can effectively reduce seismic energy transfer and improve the dynamic performance of building structures. Under high-acceleration, high-frequency, or high uniformly distributed load conditions, the advantages of soilbag cushion for energy dissipation and damping are more easily highlighted. The dynamic performance of soilbag cushion depends on the embedded depth and thickness.
GEOSYNTHETICS INTERNATIONAL
(2023)
Article
Energy & Fuels
Andrzej Strugala, Andrzej Rozwadowski, Tadeusz Dziok
Summary: The swelling phenomenon of plasticized coal grains is found to be the direct cause of coking pressure, and the ability of the plastic layer to expand strongly affects the generated coking pressure. Additionally, the migration phenomenon of plasticized coal matter also contributes to the formation of coking pressure.
Article
Chemistry, Multidisciplinary
Tae-Hwan Kim, In-Mo Lee, Hee-Young Chung, Jeong-Jun Park, Young-Moo Ryu
Summary: Soil conditioning plays a crucial role in enhancing tunnel face stability and extraction efficiency when using an EPB shield TBM to excavate tunnels. By mixing conditioning agents with weathered granite soils, optimal methods were determined, along with proposed water content ranges for effective TBM operation. Additionally, utilizing the particle-crushing characteristics of the soil, even extremely coarse and cohesionless soils can be effectively conditioned for EPB shield TBM utilization.
APPLIED SCIENCES-BASEL
(2021)
Article
Endocrinology & Metabolism
Carole Ann Spencer
Summary: This review highlights the development of laboratory thyroid tests over the past seven decades, from manual isotopically labeled iodine procedures to automated nonisotopic tests. The introduction of radioimmunoassay techniques and monoclonal antibody technology has played a crucial role in the evolution of thyroid testing. Despite improvements, current tests still face limitations in terms of numerical differences and interferences from reagents and autoantibodies.
Article
Engineering, Civil
Hyobum Lee, Dae-Young Kim, Dahan Shin, Jaehyun Oh, Hangseok Choi
Summary: An appropriate application of a soil conditioning strategy during an earth pressure balance (EPB) shield operation is crucial for reducing downtime and improving the hydro-mechanical properties of the muck. This study aims to simulate EPB tunnelling and investigate the effects of ground and foam injection conditions through laboratory-scale excavation tests. The results show that the suggested laboratory excavation test can be used to qualitatively evaluate the effects of basic soil properties and foam injection conditions on EPB shield tunnelling.
TRANSPORTATION GEOTECHNICS
(2022)
Article
Multidisciplinary Sciences
Lijuan Zhao, Meichen Zhang, Xin Jin
Summary: Researchers improved the accuracy of coal seam modeling by constructing a high-precision 3D geomechanics simulation model to achieve the goal of unmanned mining. Through optimizing the coal seam model, adding new attributes, and conducting laboratory experiments, they successfully achieved a high-precision simulation of complex coal seams.
SCIENTIFIC REPORTS
(2021)
Article
Engineering, Geological
Mark Talesnick, Motti Ringel
Summary: The development and application of a boundary friction meter is presented in this paper. The meter is able to measure the shear stress between a structural boundary and a soil mass. The calibrations and testing showed that the interface stress paths are related to surface roughness, the interface friction angles are independent of soil density, and the development of shear stress during unloading is different from that during loading.
INTERNATIONAL JOURNAL OF PHYSICAL MODELLING IN GEOTECHNICS
(2022)
Article
Engineering, Geological
Shay Nachum, Mark Talesnick, Sam Frydman
Summary: This study provides relevant relationships for the wetting-flow-swelling mechanism of compacted clay through a series of simple swelling tests. Linear relationships were observed between the percent swell and the quantity of water entering the specimens, and these relationships become invalid at a saturation level of about 85%.
GEOTECHNICAL AND GEOLOGICAL ENGINEERING
(2022)