Статті в журналах: "Reduced scale prototype"

1

Chen, Ling, Xuan Wang, Baiyi Li, and Peng Lin. "Experimental Study of Scale Effect in Tunnel Fires at Different Sealing Ratios." Fire 6, no. 3 (February 28, 2023): 92. http://dx.doi.org/10.3390/fire6030092.

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Fully or partially sealing the openings of tunnels to accelerate the self-extinction of fires provides a promising firefighting tactic to beat large fires in a long tunnel. So far, most experimental studies on the characteristics of fire with different sealing ratios have been conducted in reduced-scale tunnels. However, whether the findings in a reduced-scale tunnel can be converted to its full-scale prototype tunnel based on scaling laws has not yet been adequately studied. A series of experiments with heat-release rates of 15.8, 31.6 and 63.2 kW were conducted with sealing ratios ranging from 0% to 100% in a prototype tunnel measuring 20 m long, 0.9 m wide and 0.46 m high. The experimental results were compared with those from a 1/2 reduced-scale tunnel measuring 10 m long, 0.45 m wide and 0.23 m high. It showed that temperature rise along the tunnel in the 1/2 reduced-tunnel could be significantly underestimated. The differences in temperature rise increased monotonously with distance away from the fire seat, and they were as high as 70% at the tunnel portals, irrespective of the heat-release rates and sealing ratios. The study showed that the scale effect of fires was not sensitive to the Reynolds number of flows in tunnels. The minimal sealing ratio for the self-extinction of fires in the prototype tunnel was 85%, whilst it was 75% in the 1/2 reduced-scale tunnel, and the study revealed that the fires were much easier to extinguish in the 1/2 reduced-scale tunnel than those in the prototype tunnel, where the fires can sustain in a lower oxygen concentration. The study demonstrated that scaling laws could be invalid for tunnel fires with different sealing ratios and that results observed in reduced-scale tunnels should be further verified when applied to full-scale prototypes.

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Cervelli, F., G. Chen, G. Coignet, S. Di Falco, E. Falchini, T. Lomtadze, Z. Liu, et al. "A reduced scale e.m. calorimeter prototype for the AMS-02 experiment." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 490, no. 1-2 (September 2002): 132–39. http://dx.doi.org/10.1016/s0168-9002(02)00915-4.

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Alpaslan, Emre. "Investigation on Similarity between Dynamic Behavior of a Reduced-Scale One Span Historical Masonry Arch Bridge Model and Prototype Bridge." Civil Engineering Beyond Limits 1, no. 1 (December 17, 2019): 5–11. http://dx.doi.org/10.36937/cebel.2020.001.002.

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Experimental investigations of large and complex structural systems can be carried out by reduced-scale models in terms of convenience, time-saving and economical. This can be applied to different fields of study such as vibration, impact and explosion problems in structural engineering and allows reliable analysis to understand the static and dynamic behavior of real structures called a prototype. This study aims that a 1/3 reduced-scale model is created in the laboratory environment considering similitude requirements by selecting a single span historical masonry arch bridge as a prototype structure. For this purpose, the Operational Modal Analysis (OMA) Technique is utilized for experimental study to determine modal parameters of the prototype and model bridges. The similarity of the dynamic behavior of the reduced-scale bridge model and prototype are investigated. The analysis of the similarity in the dynamic behavior of the prototype and model bridge consists of comparing the natural frequencies and mode shapes by utilizing the modal assurance criterion (MAC) corresponding to the translational, bending and torsional modes. As a result of the study, it is concluded that the dynamic behavior of the reduced-scale bridge model is similar to the dynamic behavior of the prototype bridge.

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Al-Hassawi, Omar Dhia, and David Drake. "Innovations in Passive Downdraft Cooling Performance Evaluation Methods: Design and Construction of a Novel Environmental Test Chamber." Energies 16, no. 11 (May 27, 2023): 4371. http://dx.doi.org/10.3390/en16114371.

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Energy demand for active mechanical space cooling is projected to double by 2050. Wider adoption of passive cooling systems can help reduce demand. However, familiarity with these systems remains low, and innovation in the field is constrained due to a lack of cost-effective, accessible performance evaluation methods. This paper reports the design, construction, and commissioning of an affordable, self-contained environmental test chamber. The novel chamber replicates a range of outdoor conditions common in hot, dry regions, making possible year-round testing of reduced-scale prototypes. Data from calibration testing are reported, showing no significant difference in evaporative efficiency when a reduced-scale prototype tested in the chamber is compared with datasets from prior full-scale testing. Analyzing the results using an independent sample two-tailed t-test with a 95% confidence interval found a p-value of 0.75. While measured outlet air velocities for reduced-scale and full-scale prototypes differed to some extent (root mean square error of 0.45 m/s), results were nevertheless deemed comparable due to errors introduced by the rapid change in wind speeds and directions at full scale. Future chamber modifications will correct misalignments between data collected from the two scales and prevent observed increases in the chamber’s relative humidity levels during testing.

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Stanciu, Alexandru Lucian, Nicoleta Pascu, Constantin Dogariu, and Cristina Mohora. "Researches regarding scale reduced models for the optimisation of the aerodynamic coefficient." MATEC Web of Conferences 290 (2019): 04011. http://dx.doi.org/10.1051/matecconf/201929004011.

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Within the lifecycle of the product, the reduced models are very important for the experimental validation of the prototype. The modelling, simulation and optimization stage precedes the prototype realization, being part of the computer aided design (CAD), computer aided engineering (CAE). The physical model is a physical layout or test setup that reproduces, on a small scale, the features of the original system, in our case the vehicle body layout. The paper presents an automobile reduced model, with the aim to study the aerodynamic theory. The paper presents the algorithms of conceptual design of the scale reduced model, namely: 3D modelling, small scale modelling technology and geometric shape optimization solutions using different CAD-CAE programs.

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Brigida, M., G. A. Caliandro, C. Favuzzi, P. Fusco, F. Gargano, N. Giglietto, F. Giordano, et al. "Beam test results with a reduced scale Silicon Transition Radiation Detector prototype." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 577, no. 3 (July 2007): 519–22. http://dx.doi.org/10.1016/j.nima.2007.04.133.

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7

Tan, Xiao Jing, and Bin Wu. "Substructure Pseudo-Dynamic Testing of a Full-Scale Confined Masonry Building." Advanced Materials Research 250-253 (May 2011): 2566–70. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.2566.

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The seismic behavior of a single-story ten-bay confined masonry structure was investigated using substructure pseudo-dynamic tests. Only one bay of the prototype was regarded as the test model and the remainder was regarded as numerical model. The test results show that the test model withstood, with slight damage, strong earthquakes with peak ground acceleration of 1600 gal. It is found that prototypes of the tested type exhibited satisfactory seismic performance. Hence, the confinement can be reduced if the budget of the building is limited.

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Chen, Jian Yun, Lin Qiang Ji, Qiang Xu, and Jing Li. "Numerical Verification of Brittle Material Failure Model Test." Applied Mechanics and Materials 405-408 (September 2013): 2053–56. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.2053.

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The failure shaking table model test of mass concrete structures is an important basis for understanding to the actual failure of structures. This paper derived all kinds of similar scales between model and prototype in nonlinear dynamic shaking table test, and constructed the reduced scale nonlinear numerical simulation model. The numerical results show that the failure of model and prototype matches the nonlinear similarity theory. Besides, the effect of the characteristics of ground motion was studied and it cannot be ignored to ensure the accuracy of the test.

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9

Esmaeili, Taymaz, Tetsuya Sumi, Sameh A. Kantoush, and Yoji Kubota. "Free-Flow Sediment Flushing: Insights from Prototype-Scale Studies." Journal of Disaster Research 13, no. 4 (August 1, 2018): 677–90. http://dx.doi.org/10.20965/jdr.2018.p0677.

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Free-flow sediment flushing operation offers viable means to preserve the storage capacity of dam reservoirs as the incoming flood erodes the flushing channel, and the deposited sediment is flushed from the reservoir. This method involves complex flow patterns and flushing channel formation procedures owing to the dynamic interaction between varying flow conditions (e.g., shallow and deep flows) and moveable bed variations notably when the non-uniform sediments exist in the complex geometry of reservoirs. In the present study, first, the numerical simulation of a previously conducted free-flow sediment flushing operation in the Dashidaira and the target segment of Unazuki reservoirs using the available field-measured data were presented. Then, to improve the flushing efficiency in the Dashidaira reservoir, the effects of using a groyne were studied. A fully 3D numerical model using the finite volume method in combination with a wetting/draying algorithm was utilized to reproduce the flow velocity field and morphological bed changes. While the characteristics of the flow field can be captured by the numerical model in Dashidaira and Unazuki reservoirs, simulated bed changes in upstream areas covered with the coarser materials (e.g., study zone of Unazuki reservoir) showed some discrepancies. The outcomes also revealed that implementing a groyne at the entrance of the wide midstream of Dashidaira reservoir can locally increase the sediment erosion chance from this area and thereby can improve the flushing efficiency by approximately 10%. Therefore, the risks associated with the accumulation of distorted sediments in the wide midstream of Dashidaira reservoir within a long-term period could be reduced.

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10

Cirpici, Burak Kaan. "Predicting and comparing the fire performance of a small-scale composite structure." Challenge Journal of Concrete Research Letters 12, no. 3 (September 15, 2021): 72. http://dx.doi.org/10.20528/cjcrl.2021.03.001.

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The purpose of this paper is to investigate a strategy for the fire testing of reduced scale structural models which will help engineers design safer structures and reduce the loss from fires. The concept of this work is how composite frame floor arrangements, beam-column connections might be modelled at a small scale suitable for fire testing. Testing full-scale is expensive, besides the testing of scaled model produces reasonable results which help us to understand the failure mechanism and all significant thermo-structural responses involved in a fire. Thermal effects within a structural element generate fire curve, thermal input and structural displacement output, in other words cause and impact. Dimensional analysis, which is a condition for dynamic similarity between prototype and model, can be achieved when all the dimensionless groups are set equal for both model and prototype. On the other hand, scaling rules are used to decide how much insulating material will be used on a structure. 5-storey composite building with composite floors and steel columns has been modelled at small scale with 1/5. The obtained results from various parametric investigations show that the reduced scale model fire test method would be a feasible way to investigate the fire performance of composite structures.

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11

Tanta, Mohamed, Jose Cunha, Luis A. M. Barros, Vitor Monteiro, José Gabriel Oliveira Pinto, Antonio P. Martins, and Joao L. Afonso. "Experimental Validation of a Reduced-Scale Rail Power Conditioner Based on Modular Multilevel Converter for AC Railway Power Grids." Energies 14, no. 2 (January 18, 2021): 484. http://dx.doi.org/10.3390/en14020484.

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Rail power conditioner (RPC) has the ability to improve the power quality in AC railway power grids. This power conditioner can increase the loading capacity of traction substations, balance the active power between the feeder load sections, and compensate for reactive power and current harmonics. At present, there is increasing use of multilevel converter topologies, which provide scalability and robust performance under different conditions. In this framework, modular multilevel converter (MMC) is emerging as a prominent solution for medium-voltage applications. Serving that purpose, this paper focuses on the implementation, testing, and validation of a reduced-scale laboratory prototype of a proposed RPC based on an MMC. The developed laboratory prototype, designed to be compact, reliable, and adaptable to multipurpose applications, is presented, highlighting the main control and power circuit boards of the MMC. In addition, MMC parameter design of the filter inductor and submodule capacitor is also explained. Experimental analysis and validation of a reduced-scale prototype RPC based on MMC topology, are provided to verify the power quality improvement in electrified railway power grids. Thus, two experimental case studies are presented: (1) when both of the load sections are unequally loaded; (2) when only one load section is loaded. Experimental results confirm the RPC based on MMC is effective in reducing the harmonic contents, solving the problem of three-phase current imbalance and compensating reactive power.

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12

Alligné, S., P. Maruzewski, T. Dinh, B. Wang, A. Fedorov, J. Iosfin, and F. Avellan. "Prediction of a Francis turbine prototype full load instability from investigations on the reduced scale model." IOP Conference Series: Earth and Environmental Science 12 (August 1, 2010): 012025. http://dx.doi.org/10.1088/1755-1315/12/1/012025.

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13

Gimenez, J. R., S. C. Nassr, R. D. Maestri, and L. O. Monteggia. "Physical modelling of an upflow anaerobic sludge blanket reactor: near-field study." Water Science and Technology 45, no. 10 (May 1, 2002): 157–62. http://dx.doi.org/10.2166/wst.2002.0317.

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This paper presents a physical evaluation of an upflow anaerobic sludge blanket reactor. Specifically, the study contemplates the region influenced by the wastewater inlet jets at the bottom of the reactor, here termed the near-field area. A three-dimensional physical model of a UASB reactor in reduced scale, geometrically and dynamically correlated to a full-scale prototype was used in the evaluation. From the analysis of the major forces acting and of the physical properties investigated in the prototype, it was possible to establish non-dimensional relations that were applied to the reduced scale model, allowing the investigation of the phenomenon of interest. Tests were developed on the model to visualise the inlet flows under the buoyant effect at the bottom of the reactor, through the injection of a tracer fluid in the area with higher density, simulating the effects of the sludge bed. Based on the experimental results, it was possible to provide dimensioning criteria for the jet distribution system in UASB reactors.

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14

Gálfi, Pál-Botond, Renáta-Ildikó Száva, Ioan Száva, Sorin Vlase, Teofil Gălățanu, Károly Jármai, Zsolt Asztalos, and Gabriel Popa. "Modern Dimensional Analysis Based on Fire-Protected Steel Members’ Analysis Using Multiple Experiments." Fire 5, no. 6 (December 8, 2022): 210. http://dx.doi.org/10.3390/fire5060210.

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Nowadays, the real structures (considered as prototypes) subjected to fire are analysed by means of the behaviours of some reduced scale structures (defined as models). These prototype–model correlations are governed by the so-called dimensional analysis (DA) methods. These methods, starting from the Buckingham theorem, offer several dimensionless variables and based on them is the so-called Model Law (ML), which is able to foresee the predictable prototype’s answer based on the results of the experimental investigations performed exclusively on the model (usually manufactured at a reduced scale). Based on the MDA principles, in a previous paper the authors elaborated the complete ML for the heat transfer in beams with rectangular-hole cross-sections, considering unprotected as well as thermally protected structural elements. The authors, based on meticulous experimental investigations, obtained the validation of this ML for the unprotected steel members. In this contribution, the authors offer in a similar manner the ML validation for intumescent paint-protected steel members and thus the complete validation of their original ML. In their theoretical and experimental investigations, the authors involved both a real column’s element combined with its models manufactured at 1:2 and 1:4, as well as 1:10 scales too. Consequently, the obtained ML can be considered as generally valid, involving a real structural element and its model manufactured at the desired scale.

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Quercetti, T., K. Müller, and S. Schubert. "Comparison of experimental results from drop testing of spent fuel package design using full scale prototype model and reduced scale model." Packaging, Transport, Storage & Security of Radioactive Material 19, no. 4 (December 2008): 197–202. http://dx.doi.org/10.1179/174651008x362575.

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16

Alpaslan, Emre, Burcu Dinç, Kemal Hacıefendioğlu, Gökhan Demir, and Olgun Köksal. "Modal identification of a reduced-scale masonry arch bridge with experimental measurements and finite element method." Challenge Journal of Structural Mechanics 3, no. 3 (September 18, 2017): 108. http://dx.doi.org/10.20528/cjsmec.2017.06.012.

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This study aims to investigate modal parameters such as mode shapes, natural frequencies and damping ratios of a reduced scale one-span historical masonry arch bridge constructed in laboratory conditions by performing numerical and experimental analysis. Sarp Dere historical masonry bridge, in Ordu, Ulubey, has 15.5m in length and 4.75m in width was chosen as a prototype model. The reduced-scale bridge model and structural details were carried out in the scale of 1:12.5. Operational Modal Analysis (OMA) technique was used for experimental study. The experimental modal parameters of the bridge model were figured out by using Enhanced Frequency Domain Decomposition (EFDD). ANSYS software was used to create 3D finite element (FE) model and to expose the analytical modal parameters of the reduced-scaled bridge model. Moreover, FE model of the reduced-scale bridge model was calibrated based on the experimental results by using the Response Surface based FE model calibration technique to obtain more accurate results. The analysis results of experimental, initial and calibrated FE model were compared. It is noted that there are significant differences between the modal parameters obtained from experimental and initial FE model. Model calibration techniques are beneficial to get a more reasonable FE model.

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Qiu, Deli, Jiangdong Xu, and Hai Lin. "Numerical Analysis of the Overtopping Failure of the Tailings Dam Model Based on Inception Similarity Optimization." Applied Sciences 14, no. 3 (January 24, 2024): 990. http://dx.doi.org/10.3390/app14030990.

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The analysis of overtopping dam break caused by extreme rainstorms and other special circumstances is very important in the feasibility analysis of new construction or expansion projects of tailings reservoirs. Reduced-scale physical model tests can directly reflect the topography and dam-break influence range, but the reasonable selection of model dam material is the key to ensure the model’s similarity. Based on the similarity optimization of the limit state of scour inception of sediment particles, a new method for the model material of tailings dams can be proposed, but it needs to be verified by a similar overtopping model test. In this paper, the modeling and numerical calculation analysis of a prototype tailings dam and a similar reduced-scale model are carried out by using FLOW-3D v11.2 numerical software. The calculation results show that the model test scheme optimized by inception similarity can well reproduce the overtopping failure process of the prototype dam.

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Teixeira, Eder Daniel, Paulo Ricardo Behrens Franca, Edna Maria de Faria Viana, Marco Tulio Correa de Faria, Aloysio Portugal Maia Saliba, and Carlos Barreira Martinez. "Reduced hydraulic model of Forquilha IV tailings dam." Rem: Revista Escola de Minas 68, no. 1 (March 2015): 29–36. http://dx.doi.org/10.1590/0370-44672015680187.

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This paper presents the development of a reduced hydraulic model (RHM) for the outflow operating system at the Forquilha IV (scale 1:10) tailings dam, owned by Vale S.A. The studies were performed by Centro de Pesquisas Hidráulicas e Recursos Hídricos (CPH) of Universidade Federal de Minas Gerais (UFMG) and the company Vogbr Recursos Hídricos & Geotecnia Ltda. We present here a brief description of the model construction and the test battery set for the structure’s hydraulic analysis. RHM involves the hillside culvert, the dissipation box and the exit to the restitution tunnel. The RHM project represents an essential step in the first analysis of the hydraulic behavior of the prototype, considering the designed flood station (ten thousand-year flood flow), as well as the analysis of its operation with more frequent flows.

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Holley, Simone, Rebecca Knibb, Sue Latter, Christina Liossi, Frances Mitchell, Ruth Radley, and Graham Roberts. "Development and validation of the Adolescent Asthma Self-Efficacy Questionnaire (AASEQ)." European Respiratory Journal 54, no. 1 (May 2, 2019): 1801375. http://dx.doi.org/10.1183/13993003.01375-2018.

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Perceived self-efficacy is the belief that one can manage prospective situations. Good asthma self-management self-efficacy is associated with better asthma outcomes. However, a well-developed and validated tool to measure adolescent asthma self-management self-efficacy is lacking. Our objective was to develop and validate an Adolescent Asthma Self-Efficacy Questionnaire (AASEQ).The first stage of the study included a review of the literature, interviews with adolescents with asthma and consultations with parents and relevant healthcare professionals to develop a prototype scale. To assess reliability and validity, a further group of adolescents completed the prototype scale, the General Self-Efficacy Scale and KidCOPE (measures coping styles). Retesting was undertaken to assess longitudinal validity.Interviews with 28 adolescents and consultations with other stakeholders resulted in a 38-item prototype scale. Key themes were medication, symptom management, triggers, knowledge, attitude and beliefs around asthma, supportive relationships, schools and healthcare professionals. The prototype scale was completed by 243 adolescents. Factor and reliability analysis reduced it to a 27-item scale with four subsections: symptom management; medication; friends, family and school; and asthma beliefs. The 27-item scale had respectable to excellent internal consistency (α's 0.78–0.91) with results that were stable over time (intra-class correlation=0.82) in 63 subjects who completed it twice. Better adolescent asthma self-efficacy was associated with better general self-efficacy and indices of better asthma management.The AASEQ is a reliable and valid tool that is likely to aid future research and practice focused on adolescent asthma self-management and could be a useful intermediate outcome measure to assess the impact of behavioural interventions.

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20

Cox, Daniel, Kiernan Kelty, Pedro Lomonaco, Tori Tomiczek, and Kayla Ostrow. "ARE REDUCED-SCALE EXPERIMENTS OF WAVE DAMPING BY VEGETATION SUITABLE FOR ENGINEERING WITH NATURE?" Coastal Engineering Proceedings, no. 37 (September 1, 2023): 48. http://dx.doi.org/10.9753/icce.v37.waves.48.

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Wave damping by vegetation has been included in many numerical models for coastal engineering primarily through a parameterized expression for the wave height decay following Mendez and Losada (2004). CD is an empirical coefficient often derived from reduced-scale laboratory experiments in which alpha is measured directly. Multiple values of CD can be determined from a series of tests and CD is often given as a function of the Reynolds number, Re. These empirical relations for CD are subsequently used along with the vegetation and wave properties to estimate the wave damping rate in numerical models. Although CD has been shown to have a Reynolds-dependence, it is well known that Reynolds similitude cannot be held between model and prototype when Froude similitude is applied. This disparity raises a fundamental scaling issue to be explored in this paper: Are drag coefficients obtained by reduced-scale experiments of wave damping by vegetation suitable for engineering design?

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21

Morchio, Stefano, Marco Fossa, Antonella Priarone, and Alessia Boccalatte. "Reduced Scale Experimental Modelling of Distributed Thermal Response Tests for the Estimation of the Ground Thermal Conductivity." Energies 14, no. 21 (October 22, 2021): 6955. http://dx.doi.org/10.3390/en14216955.

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The knowledge of the ground thermal properties, and in particular the ground thermal conductivity is fundamental for the correct sizing of the Ground Coupled Heat Pump (GCHP) plant. The Thermal Response Test (TRT) is the most used experimental technique for estimating the ground thermal conductivity. This paper presents an experimental setup aimed to realise a suitable scale prototype of the real borehole heat exchanger (BHE) and the surrounding ground for reduced scale TRT experiments. The scaled ground volume is realised with a slate block. Numerical analyses were carried out to correctly determine suitable geometric and operational parameters for the present setup. The scaled heat exchanger, inserted into the block, is created with additive technology (3D printer) and equipped with a central electrical heater along its entire depth and with temperature sensors at different radial distances and depths. Present measurements highlight the possibility to reliably perform a TRT experiment and to estimate the slate/ground thermal conductivity with an agreement of about +12% with respect to measurements provided by a standard commercial conductivity meter on proper cylindrical samples of the same material and onto 10 different portions of the slate block.

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22

Kafafy, Raed, Mohamed Okasha, Shamma Alblooshi, Hessa Almansoori, Salma Alkaabi, Salma Alshamsi, and Turfa Alkaabi. "A remotely-controlled micro airship for wireless coverage." Applied Research and Smart Technology (ARSTech) 3, no. 2 (December 27, 2022): 72–80. http://dx.doi.org/10.23917/arstech.v3i2.1190.

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This paper describes the design process and prototype development of a remotely controlled airship for wireless coverage. The airship is designed to be used as a platform to provide wireless coverage for rural areas. The design process follows a systematic design process for lighter-than-air vehicles, modified to impart slight heaviness to the vehicle. A remotely-controlled, thrust-vectored electric propulsion system offsets the slight vehicle heaviness. The electric propulsion system comprises two tilting rotors for takeoff, cruise, hovering, and horizontal manoeuvring. A rudder-less, rotor-less, cruciform fin design was implemented. A reduced-scale prototype of the airship was developed to prove the design concept. The airship prototype was successfully tested in an indoor environment.

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Wang, Yu Heng, Feng Liu, Xiang Hua Zhang, and Sheng Ding. "Numerical Simulation on Similarity of Thermal-Mechanical Effects of Thin-Walled Pressure Vessel Irradiated by Laser." Advanced Materials Research 314-316 (August 2011): 1965–69. http://dx.doi.org/10.4028/www.scientific.net/amr.314-316.1965.

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In laser process and laser scientific experiments it is an important research method to investigate analogy of physical parameters between the scale down models and the prototype structure by reduced-scale experiments. To the problem of the thermal-mechanical effects of the thin-walled pressure vessel irradiated by continuous wave (CW) laser, a series of approximatively geometrically scaling models with different scale-ratios are established in this paper. Laser flux and ratios of r(radius of laser spot) to R(radius of shells) keep the same for each scaling model. The similarity regularities of thermal-mechanical effects are analyzed and discussed by means of FEM numerical simulation method. The calculation results can give a guide to design for the scale down models and select for laser parameters in reduced-scale experiments.

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Willauer, Heather D., Matthew J. Bradley, Jeffrey W. Baldwin, Joseph J. Hartvigsen, Lyman Frost, James R. Morse, Felice DiMascio, Dennis R. Hardy, and David J. Hasler. "Evaluation of CO2 Hydrogenation in a Modular Fixed-Bed Reactor Prototype." Catalysts 10, no. 9 (August 26, 2020): 970. http://dx.doi.org/10.3390/catal10090970.

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Low-cost iron-based CO2 hydrogenation catalysts have shown promise as a viable route to the production of value-added hydrocarbon building blocks. It is envisioned that these hydrocarbons will be used to augment industrial chemical processes and produce drop-in replacement operational fuel. To this end, the U.S. Naval Research Laboratory (NRL) has been designing, testing, modeling, and evaluating CO2 hydrogenation catalysts in a laboratory-scale fixed-bed environment. To transition from the laboratory to a commercial process, the catalyst viability and performance must be evaluated at scale. The performance of a Macrolite®-supported iron-based catalyst in a commercial-scale fixed-bed modular reactor prototype was evaluated under different reactor feed rates and product recycling conditions. CO2 conversion increased from 26% to as high as 69% by recycling a portion of the product stream and CO selectivity was greatly reduced from 45% to 9% in favor of hydrocarbon production. In addition, the catalyst was successfully regenerated for optimum performance. Catalyst characterization by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), along with modeling and kinetic analysis, highlighted the potential challenges and benefits associated with scaling-up catalyst materials and processes for industrial implementation.

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Khemacheevakul, Khemiga, John Wolodko, Ha Nguyen, and Wendy Wismer. "Temporal Sensory Perceptions of Sugar-Reduced 3D Printed Chocolates." Foods 10, no. 9 (September 3, 2021): 2082. http://dx.doi.org/10.3390/foods10092082.

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Sugar-reduced chocolates with desirable sensory qualities and sweetness can be created using a 3D printer by layering chocolates with different sugar concentrations. This study aimed to evaluate the temporal sensory profile, perceived sweetness intensity, and acceptance of prototype sugar-reduced and non-sugar-reduced 3D printed chocolates. A consumer panel (n = 72) evaluated the sensory profiles of six-layered chocolates. Sensory profiles were determined by temporal dominance of sensations (TDS), overall sweetness by a five-point intensity scale, overall liking by the nine-point hedonic scale, and differences among chocolates over time were visualized by principal component analysis (PCA). Layering by 3D printing achieved a 19% reduction in sugar without changes in the perceived overall sweetness and overall liking. Layering order of high and low sugar chocolate influenced the perceived overall sweetness and temporal sensory profiles of 3D printed chocolates with different total sugar concentrations. The dominance of attributes associated with milk chocolate was observed to increase sweetness perception while the dominance of attributes associated with dark chocolate was observed to decrease overall sweetness perception. Three-dimensional food printing technology is progressing rapidly, and further sugar reduction could be achieved with refined research methods.

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Sedran, Gabriel, Dieter FE Stolle, and Robert G. Horvath. "An investigation of scaling and dimensional analysis of axially loaded piles." Canadian Geotechnical Journal 38, no. 3 (June 1, 2001): 530–41. http://dx.doi.org/10.1139/t00-122.

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This paper investigates the use of the concepts of similarity and dimensional analysis to interpret results from reduced-scale models of axially loaded piles embedded in sand. These concepts are reviewed in the light of a pilesoil system and its response to static or half-sine impulsive loading. It is suggested that constitutive similarity between model and prototype responses can be fulfilled without scaling gravity, provided that a stress scaling factor equal to one is selected. The scaling factors are validated with numerical simulations via finite element analyses by comparing the results from full-scale and special reduced-scale pilesoil models. It is also shown that a frustum confining vessel has the potential to provide more realistic scaled responses than are obtained with the classical 1g devices. A series of pile test responses are simulated for different pile lengths and different coefficients of lateral earth pressure. A set of scaling factors is presented and a particular set of dimensionally homogeneous π groups is proposed to characterize the behaviour of the pilesoil system. Simulated responses are interpreted using the proposed π groups to obtain functional relations relevant to the pilesoil problem.Key words: reduced-scale modelling, dimensional analysis, similarity, model piles, sands.

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27

Campiche, Alessia. "Numerical Modelling of CFS Three-Story Strap-Braced Building under Shaking-Table Excitations." Materials 14, no. 1 (December 29, 2020): 118. http://dx.doi.org/10.3390/ma14010118.

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In recent research activities, shake-table tests were revealed to be useful to investigate the seismic behavior of cold-formed steel (CFS) buildings. However, testing full-scale buildings or reduced-scale prototypes is not always possible; indeed, predicting tools and numerical models could help designers to evaluate earthquake response. For this reason, numerical modelling of two strap-braced prototype buildings, recently tested on shake-table at University of Naples Federico II in cooperation with Lamieredil S.p.A. company, was developed. The models were validated trough the comparison between experimental and numerical results, in term of dynamic properties (fundamental period of vibration and modal shapes), peak roof drift ratios and peak inter-story drift ratios. Although dynamic properties of mock-ups were captured with accuracy by the developed models, the comparison highlighted the need to consider accumulation of damage and rocking phenomenon in the modelling to capture with good accuracy the seismic behavior of CFS strap-braced building, subjected to high intensity records.

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28

Du, Dong Mei, Hong Li, Chun Shui Zhu, and Qing He. "Virtual Prototype Modeling and Starting Method of Belt Conveyor." Applied Mechanics and Materials 148-149 (December 2011): 879–82. http://dx.doi.org/10.4028/www.scientific.net/amm.148-149.879.

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Large scale belt conveyor is a key device to transport bulk-solid material for long distance. It is necessary to build rational virtual prototype model, analysis dynamic performance of belt conveyor. Comparing with traditional physical prototyping and experimental way, shorter design cycle and lower development costs will be got by using virtual prototype. It is helpful to choose the best design which is rational in technique, safe and reliable in running, feasible in economy. Considered actual working conditions, a virtual prototype model is built and validated by dynamics analysis. Three starting methods including direct starting mode, traditional Harrison method and soft starting are compared. The simulation results of virtual prototype show that direct starting method will lead to higher dynamic tension extreme value and larger fluctuation, dynamic tension is significantly reduced with the traditional Harrison method, and the average dynamic tension of soft starting consider the actual condition is dropped to minimum and the whole system is more stable.

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29

Wang, Ai Lun, and Li Kun Huang. "Research on Similarities between Abnormal Rotor Model and the Prototype Based on Dynamic Similarity." Advanced Materials Research 591-593 (November 2012): 1991–95. http://dx.doi.org/10.4028/www.scientific.net/amr.591-593.1991.

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The natural frequencies of the reduced scale model are higher than that of the prototype, which make it quite difficult to conduct the experimental research on the dynamic characteristics of the rotor system by using normal rotor model. Aiming at this problem, this paper has deduced the similarity criterion of abnormal rotor model based on equation analysis, and the dynamic similarity conditions between abnormal rotor model and the prototype are also discussed. Next, the mass matrix and flexibility matrix are presented based on the lumped parameter model of the rotor system. Finally, the similarities among normal rotor model, abnormal rotor model and the prototype are comparatively analyzed. The results show that the natural frequencies of abnormal rotor model and that of the prototype are all the same while the radial scaling factor is the square of the axial scaling factor. And it provided the theoretical basis for experimentally studying the dynamic characteristics of the rotor system.

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30

Ghorbani, Behnam, Arul Arulrajah, Guillermo A. Narsilio, Suksun Horpibulsuk, and Apinun Buritatum. "Geothermal Pavements: Experimental Testing, Prototype Testing, and Numerical Analysis of Recycled Demolition Wastes." Sustainability 15, no. 3 (February 2, 2023): 2680. http://dx.doi.org/10.3390/su15032680.

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Geothermal pavements have the potential to reduce the pavement surface temperature by circulating fluid in pipes within the pavement structure. This research investigated an innovative geothermal pavement system with multiple benefits, such as reducing the surface temperature and harvesting heat energy for power generation. This research aimed to provide an understanding of the mechanical properties of geothermal pavements constructed with construction and demolition (C&D) waste materials through large-scale physical testing, experimental testing, small-scale prototype testing, and numerical simulation. The mechanical properties of the geothermal pavement system were assessed under long-term traffic loading conditions using a prototype test system. The repeated load triaxial and repeated-load California bearing ratio tests were also undertaken to evaluate the effect of pipe inclusion on the permanent deformation, stiffness, and strength of the pavement base. A numerical model was subsequently developed and calibrated using the data from small-scale prototype testing. In addition, the effects of the flow rate and pipe materials on the thermal performances of the geothermal pavements were also investigated in this research. The inclusion of pipes in the pavement base layer was found to have negligible detrimental effects on the deformation behavior of RCA. The resilient moduli of recycled concrete aggregate (RCA) samples slightly decreased with the inclusion of pipes. An HDPE pipe reduced the stiffness of the RCA + HDPE mix. On the other hand, a copper pipe’s high stiffness improved the mix’s strength. The numerical simulations indicated that for the HDPE pipe, increasing the flow rate from 500 mL/min to 2000 mL/min reduced the surface temperature by approximately 1.3%, while using the copper pipe resulted in an approximately 4% further decrease in the surface temperature compared to the HDPE pipe.

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31

Lindeberg, Tony. "Provably Scale-Covariant Continuous Hierarchical Networks Based on Scale-Normalized Differential Expressions Coupled in Cascade." Journal of Mathematical Imaging and Vision 62, no. 1 (October 25, 2019): 120–48. http://dx.doi.org/10.1007/s10851-019-00915-x.

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Abstract This article presents a theory for constructing hierarchical networks in such a way that the networks are guaranteed to be provably scale covariant. We first present a general sufficiency argument for obtaining scale covariance, which holds for a wide class of networks defined from linear and nonlinear differential expressions expressed in terms of scale-normalized scale-space derivatives. Then, we present a more detailed development of one example of such a network constructed from a combination of mathematically derived models of receptive fields and biologically inspired computations. Based on a functional model of complex cells in terms of an oriented quasi quadrature combination of first- and second-order directional Gaussian derivatives, we couple such primitive computations in cascade over combinatorial expansions over image orientations. Scale-space properties of the computational primitives are analysed, and we give explicit proofs of how the resulting representation allows for scale and rotation covariance. A prototype application to texture analysis is developed, and it is demonstrated that a simplified mean-reduced representation of the resulting QuasiQuadNet leads to promising experimental results on three texture datasets.

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32

Rocha e Silva, Fernanda Cristina P., Nathalia Maria P. Rocha e Silva, Ivison Amaro da Silva, Pedro P. Ferreira Brasileiro, Juliana M. Luna, Raquel D. Rufino, Valdemir A. Santos, and Leonie A. Sarubbo. "Oil removal efficiency forecast of a Dissolved Air Flotation (DAF) reduced scale prototype using the dimensionless number of Damköhler." Journal of Water Process Engineering 23 (June 2018): 45–49. http://dx.doi.org/10.1016/j.jwpe.2018.01.019.

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33

Gallo, Giuseppe, Domenico Lo Presti, Danilo Luigi Bonanno, Giovanni Bonanno, Paola La Rocca, Santo Reito, Francesco Riggi, and Giuseppe Romeo. "Proof-of-Principle of a Cherenkov-Tag Detector Prototype." Sensors 20, no. 12 (June 18, 2020): 3437. http://dx.doi.org/10.3390/s20123437.

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In a recent paper, the authors discussed the feasibility study of an innovative technique based on the directionality of Cherenkov light produced in a transparent material to improve the signal to noise ratio in muon imaging applications. In particular, the method was proposed to help in the correct identification of incoming muons direction. After the first study by means of Monte Carlo simulations with Geant4, the first reduced scale prototype of such a detector was built and tested at the Department of Physics and Astronomy "E. Majorana" of the University of Catania (Italy). The characterization technique is based on muon tracking by means of the prototype in coincidence with two scintillating tiles. The results of this preliminary test confirm the validity of the technique and stressed the importance to enhance the Cherenkov photons production to get a signal well distinguishable with respect to sensors and electronic noise.

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34

Womac, Alvin R., Erin E. Byers, Kimberly G. Thomas, Boone Hillenbrand, Andrew Smith, and Venkata Sambasiva Prasad Bitra. "Modeling Cotton Module Builder and Loader to Enhance Biomass Testing." Applied Engineering in Agriculture 37, no. 5 (2021): 911–28. http://dx.doi.org/10.13031/aea.14414.

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HighlightsPhysical models of module builder and module loader were developed to enhance biomass testing with reduced mass and volume of biomass.Models used dimensional analysis, Pi Terms, and engineering factors and emphasis on reduced module upsetting and disturbance.Some engineering terms such as tamping face pressure and velocity, and particle size were not scaled to reduce biological-material distortions.Switchgrass bulk density at 8% wet basis for prototype and model were 115 and 80 kg m-3, respectively.Abstract. The objective was to design and implement separate models of a first-generation cotton module builder and a module loader that facilitated tamping quasi-confined biomass and the minimal disturbances of modules during emptying from the builder and during loader operations including unloading. The 122-cm long model, compared to 978-cm long prototype, reduced the mass of module contents required for testing from 6188 to 44 kg, or by a factor of 141:1. The tamping process was emphasized with constant tamper pressure of 76.6 kPa applied to module contents for prototype and model. Consistent properties such as SG characteristic length were also held constant among module sizes to reduce the complications of introducing un-anticipated biological-material distortions. Similarities in design aspects beyond dimensional analysis were emphasized to reduce inadvertent module upset and disturbance. Hydraulics ensured uniform tamping and lifting. An efficient module box for the model resembled the prototype-scale commercial unit with z-shaped ribs and upward-tapered module sides. Seed cotton [8% moisture wet basis (w.b.)] bulk densities for prototype and model were 166 and 107 kg m-3, respectively. Bulk densities for switchgrass (8% w.b.) prototype and model were 115 and 81 kg m-3, respectively. Reduced bulk density of models was attributed to essentially no external confinement stresses being applied to modules at rest resulting in only self-imposed confinement stresses due to module content over-burden. However, unconfined modules may have a role in handling biomass for reduced distances. Also related to minimizing module upsetting, module loading emphasized the counter-motions of advancing the loader versus the conveyor motion in the opposite direction, all driven with an electric motor. Module stability during loading was attributed to a self-imposed normal stress of module weight acting downward onto a horizontal plane of the module. The fixed loading angle of 15° and material bulk properties were held constant between prototype and model. Dependent variable for the module loader was normal stress for module stability. Normal stresses resulting from seed cotton at 8% moisture content (wet basis) were 4.754 and 0.637 kPa, respectively. Normal stresses for chopped SG at 8% moisture content (wet basis) were 3.302 and 0.484 kPa, respectively. Biomass modules would not be as stable as cotton modules based on normal stress, and due to lack of intermeshing cotton fibers. Results of loading and unloading a dozen SG model modules resulted in one module failure due to upset, and that was attributed to a 2-layer fill versus 3-layer fill for that one module. Keywords:

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35

Weiß, Gebhard J., and Steven Michelbach. "Vortex separator: dimensionless properties and calculation of annual separation efficiencies." Water Science and Technology 33, no. 9 (April 1, 1996): 277–84. http://dx.doi.org/10.2166/wst.1996.0229.

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Vortex separators as new devices for combined sewer overflows (CSOs) claim good efficiencies which can be confirmed by laboratory tests. Such model tests are usually performed in reduced scale and under steady-flow conditions. This paper describes a possible way to transfer model test results to the prototype scale. As a first step, the most essential parameters must be accounted for using a proper dimensional analysis which also considers scale effects. It will result in dimensionless efficiency curves which allow prediction of prototype efficiencies, yet valid for steady flow only. To take into account the variability of annual inflow as well as dynamic effects like filling and emptying of a particular separator, the efficiency characteristics of the separator are combined with a quantity-quality simulation model. Such a numerical model is able to compute inflow and outflow hydrographs and pollutographs and to account for the catchment data at the given site. It allows the computation of annual pollutant loads as well as of the percentage of sewage sediment fed to the treatment plant, i.e. an annual separation efficiency.

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36

García-Sanz, M., and J. Flórez. "A Low-Cost Control Experiment for Systems with Large Time Constants and Unknown Time Delays." International Journal of Electrical Engineering & Education 31, no. 3 (July 1994): 252–63. http://dx.doi.org/10.1177/002072099403100307.

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A low-cost control experiment for systems with large time constants and unknown time delays A prototype that represents the thermal behaviour of a building modelled at reduced scale with a central heating system is described. It is a simple, robust experiment which can be used for a variety of control studies, especially those related with systems that present large time constants and unknown time delays.

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37

Galka, Alexander Georgievich, Alexander Vladimirovich Kostrov, Stanislav Eduardovich Priver, Askold Vitalievich Strikovskiy, Vladimir Vladimirovich Parshin, Evgeny Alexandrovich Serov, Andrey Sergeevich Nikolenko, Sergey Vladimirovich Korobkov, and Mikhail Evgenievich Gushchin. "Microwave Cavity Sensor for Measurements of Air Humidity under Reduced Pressure." Sensors 23, no. 3 (January 29, 2023): 1498. http://dx.doi.org/10.3390/s23031498.

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A high-sensitivity sensor for measuring moisture content in the air or air humidity under low pressure was designed on the basis of a half-wave coaxial microwave cavity. The method of measuring small variations in the signal phase at a cavity excitation frequency of 1.63 GHz was applied to detect low densities of water vapor. It allows the detection of variations in dielectric air permittivity in the seventh decimal place. A prototype of the sensor was tested in a vacuum chamber. It was calibrated by comparing the test results with the readings of a commercial pressure gauge and using the independent method of measuring the moisture content in rarefied air on the basis of the absorption of millimeter waves in the local line of water vapor at 183 GHz. The developed sensor can be used in laboratory experiments and full-scale geophysical research in the atmosphere onboard various aircrafts.

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Száva, Renáta-Ildikó, Ioan Száva, Sorin Vlase, Pál-Botond Gálfi, Károly Jármai, Teofil Gălățeanu, Gabriel Popa, and Zsolt Asztalos. "Modern Dimensional Analysis-Based Steel Column Heat Transfer Evaluation Using Multiple Experiments." Symmetry 14, no. 9 (September 19, 2022): 1952. http://dx.doi.org/10.3390/sym14091952.

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In order to foresee the response during the fire of a real symmetrical structure (prototype), nowadays engineers apply methods which involve the associated reduced-scale model’s behaviors, mainly dimensional analysis behaviors. Between the dimensional analysis methods, the so-called Modern Dimensional Analysis (MDA), developed by Szirtes, fulfills all engineering requirements compared with the classical one. The authors used this new proposed method to describe their original electric fire simulation testing bench, as well as the Model Law (using MDA) for the heat transfer in tubular rectangular bars. So, a validation of the Model Law was performed based on several scrupulous experimental investigations both on a real column’s segment and its associated reduced-scale models manufactured at 1:2; 1:4, as well as 1:10 scales. The original heating system, the elaborated protocol, the deduced Model Law, and the results of the experimental investigations represent the contributions of the authors in the field of metallic structures subject to fires. The results validate the possibility of using MDA in the case of heat transmission.

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39

Zhao, Zhiwei, Jinqiu Wu, Xiaofei Qi, Gang Qiao, Wenbo Zhang, Chaofan Zhang, and Kang Guo. "Design of a Broadband Cavity Baffle Bender Transducer." Journal of Marine Science and Engineering 10, no. 5 (May 16, 2022): 680. http://dx.doi.org/10.3390/jmse10050680.

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As low-frequency and broadband acoustic emission capability is beneficial to the detection range and acoustic communication speed of small scale autonomous underwater vehicles (AUV), this type of transducer is required, especially in cases of complex acoustic environments. A broadband bender transducer with cavity baffle that suits small scale AUV is proposed. Rather than additional benders, a passive cavity baffle, which would be capable of providing mutual radiation and a fluid cavity mode, is introduced to a single bender. The bending resonant frequency is reduced by the mutual radiation between the bender and the cavity baffle, the cavity baffle extends the lower limit of the available frequency band of the transducer, the liquid resonant frequency behind the former expands the higher limit, then the cavity baffle bender transducer fills the role of radiating low-frequency and broadband emissions through multimode coupling. The finite element method is used to analyze the acoustic performance of the transducer under different baffle conditions. Then, a prototype of the broadband cavity baffle bender transducer is developed according to the optimized parameters of simulation. The acoustic parameters of the prototype were measured in an anechoic pool. The resonant frequency measured in water of the bender itself is 3 kHz, and the −3dB bandwidth is 560 Hz. The prototype test results show that the cavity baffle scheme can improve the −3dB bandwidth of the bender from 560 Hz to 1000 Hz, which fundamentally realizes the expectations of the prototype design.

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40

Gaztanaga, Haizea, Ion Etxeberria-Otadui, Dan Ocnasu, and Seddik Bacha. "Real-Time Analysis of the Transient Response Improvement of Fixed-Speed Wind Farms by Using a Reduced-Scale STATCOM Prototype." IEEE Transactions on Power Systems 22, no. 2 (May 2007): 658–66. http://dx.doi.org/10.1109/tpwrs.2007.895153.

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41

Joo, Jae Young, Chang Suk Kang, Soon Sub Park, and Sun Kyu Lee. "Fabrication of a Beam Shaping Lens for Chip Scale Packaged LEDs." Key Engineering Materials 447-448 (September 2010): 101–5. http://dx.doi.org/10.4028/www.scientific.net/kem.447-448.101.

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In this paper, we demonstrated the machining process of a novel Light Emitting Diodes (LED) beam shaping lens, called TIR Fresnel lens, for GaN-based blue Chip Scale Packaged (CSP) LEDs. Upon achieving a precise alignment of the tool and identifying the best manufacturing condition, we have successfully fabricated a prototype of this lens on poly methyl methacrylate (PMMA) plate. The form error of the central aspheric lens was less than 1 μm deviation, and surface quality of the Fresnel facets were sufficient for Total Internal refraction without any burr or adhesion of the machined chip. Fabricated TIR Fresnel lens reduced the viewing angle of the testing CSP LED from 140° to 17.4° in FWHM. The proposed lens produced extreme compactness as well as high collimation efficiency, thereby applicable to an ultra-thin optical system.

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42

Garrick, Taylor R., Yangbing Zeng, Jason B. Siegel, and Venkat R. Subramanian. "From Atoms to Wheels: The Role of Multi-Scale Modeling in the Future of Transportation Electrification." Journal of The Electrochemical Society 170, no. 11 (November 1, 2023): 113502. http://dx.doi.org/10.1149/1945-7111/ad0919.

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Traditionally, prototype hardware is built for validation testing to ensure battery systems design changes meet vehicle-level requirements, which is expensive both in cost and time. Virtual engineering (VE) of battery systems for electric vehicle (EV) propulsion offers a reduced-cost alternative to the traditional development process and uses multi-scale modeling to virtually probe the impact of design changes in a particular part on the overall performance of the system. This allows for rapid iteration over multiple design spaces, without committing to build hardware. This perspective article discusses current trends in VE for EV applications and proposes improvements to accelerate EV adoption.

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43

Sun, Shu Hong, Xue Song Zhang, and An Bang Gu. "Study and Model Test on the Anchorage Area for Chongqing Jiayue Bridge’s PC Box Girder." Advanced Materials Research 243-249 (May 2011): 1597–604. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.1597.

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The research work is described about the numerical analysis and reduced scale prototype model test of Chongqing Jiayue Bridge’s PC beam, which has some special structure details. The structure’s practicality of the PC box girder’s anchorage is demonstrated through computing, at the same time, the security of the anchorage undertaking kiloton force is experimented by test. Some conclusions and suggestions are drowning through such research work which are helpful to design and construction.

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44

Benslimane, Anas, Jamal Bouchnaif, Mohamed Azizi, and Khalid Grari. "An experimental study of the unbalance compensation by voltage source inverter based STATCOM." International Journal of Power Electronics and Drive Systems (IJPEDS) 7, no. 1 (March 1, 2016): 45. http://dx.doi.org/10.11591/ijpeds.v7.i1.pp45-55.

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This work presents an experimental study of the unbalance compensation caused by the high speed railway substations in the high-voltage power grid with a shunt voltage source inverter based STATCOM. This experimental study is realized on a reduced scale prototype. The Control of inverter is implemented in a DSP card. The practical results presented in this paper are shown the performance of unbalance compensation by VSI_STATCOM in static and dynamic regime.

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45

Yang, Haisheng, Mingzhou Su, Yong Xiao, and Dan Gan. "Cyclic Behavior of Gabled Frames with Web-Tapered Columns and Rafters." Materials 16, no. 1 (December 28, 2022): 307. http://dx.doi.org/10.3390/ma16010307.

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Cyclic loading tests were conducted on three 1/2-scale, half-bay steel gabled frames (SGFs) to investigate their seismic performance. The three specimens with reduced joint stiffness were designed based on the prototype drawing shown in China design guideline 02SG518—1: specimen SV1 with a reduced thickness of the joint end-plate and bolt diameter, specimen SV2 with a reduced number of bolts, and specimen SV3 with a reduced bolt diameter. The load capacity, rotational stiffness, rotational capacity, and ultimate failure mode of specimens SV1, SV2, and SV3 were investigated. The experimental results showed that specimen SV1 failed due to the local buckling of the lower flange of the rafter, and specimens SV2 and SV3 due to the local buckling of upper flange of the rafter. The joint zone of all specimens kept well, indicating that the prototype joint had a large margin of safety. The hysteresis curves of all specimens were not full, and the ductility and energy dissipation capacity were limited. The end-plate thickness, bolt diameter, and steel grade affected the hysteresis performance of the SGF little. A refined finite element model was established, and the predicted results compared well with the test results. The test and analysis results demonstrated that there was slight utilization and distribution of post-buckling strength.

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46

Ullah, H., M. Rizwan, M. Fahad, and S. A. A. Shah. "Seismic Evaluation of the RC Moment Frame Structure using the Shake Table." Engineering, Technology & Applied Science Research 11, no. 1 (February 6, 2021): 6674–79. http://dx.doi.org/10.48084/etasr.3959.

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This paper presents the findings of an experimental investigation on a reinforced concrete frame structure (ordinary moment resistant frame). The test model was subjected to lateral excitation employing the 1994 Northridge earthquake accelerogram. The reinforced concrete test model was fabricated in 1:3 reduced scale acquiring dimensional similarities. The utilized ingredient mix ratio was 1:1.65:1.75 and the water to binder ratio was 0.47. The dynamic characteristics (natural frequency and elastic viscous damping) were calculated using the free vibration record. Story shear, drift, and displacement profiles were drawn using multiple excitation records along with damage patterns and capacity curves. The natural frequency of 2.47Hz was calculated for the test specimen, which is equivalent to 1.41Hz for the prototype. Structural damping (elastic viscous) of 12.36% was calculated for the prototype.

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47

Jodin, Gurvan, Johannes Scheller, Eric Duhayon, Jean François Rouchon, Michael Triantafyllou, and Marianna Braza. "An Experimental Platform for Surface Embedded SMAs in Morphing Applications." Solid State Phenomena 260 (July 2017): 69–76. http://dx.doi.org/10.4028/www.scientific.net/ssp.260.69.

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This article will address the modeling and control of surface embedded shape memory alloys (SMAs) for the camber modification of a hybrid morphing airfoil. An analytical model will be derived. The results of this models will be discussed and compared to the experiments. The advantages of this modeling approach will be highlighted and alternatives will be briefly revisited. This discussion will figure into the utility of these models in the sizing of a full scale prototype of a SMA actuated active trailing edge of an airfoil. Throughout this article the prototype specifications are detailed and the design choices will be discussed. Performance improvements stemming from the inherent nature of the SMAs will be analyzed. It will be shown in this article that through the use of forced convection the overall cycle time can be reduced.

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Abdurrahmat, Asep Suryana, Rian Arie Gustaman, and Yuldan Faturahman. "Working Station Model Based on Mathematic Model of Anthropometry for Embroidery Workers." Open Access Macedonian Journal of Medical Sciences 10, E (May 13, 2022): 965–70. http://dx.doi.org/10.3889/oamjms.2022.9638.

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BACKGROUND: Often, the embroidery craftsmen do their work by ignoring the unbalance of their anthropometric size with the size of the tables and chairs used. This condition causes not ergonomic sitting position when they are working that will trigger variety of subjective complaints of craftsmen, especially in muscles and joints. AIM: Conducted development research using 4D model (devine, design, develop, and disseminate) based on anthropometry size to build chair and table as more ergonomic work station for embroidery craftsmen. METHODS: The first three stages are done by analyzing the compatibility of anthropometry of the body with the size of work station used by mathematical approach and laboratory scale test. The acceptance level of craftsmen on the prototype of work station model measures by technology accepted model that conducted on a public scale. RESULTS: The result of this research is the establishment of more ergonomic prototype of work station model for embroidery craftsmen and based on the result of public scale examination of 180 embroidered craftsmen showed that 63% of respondents stated less subjective complaints of muscle and joint disorders at the shoulders, 71% subjective complaints of muscle and joint disorders in the upper arm, and respondents stated reduced subjective complaints of muscle and joint disorders in the 56% after using a new work station model. CONCLUSION: However, it is still necessary to make improvements to the prototype of the work station model to be more ergonomic and to suppress the emergence of subjective complaints of muscle disorders and joints of embroidery craftsmen.

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Sparke, Marc-André, Achim Wegscheider, Patrick Winterhagen, Ute Ruttensperger, Martin Hegele, and Jens Norbert Wünsche. "Air-based Mechanical Stimulation Controls Plant Height of Ornamental Plants and Vegetable Crops under Greenhouse Conditions." HortTechnology 31, no. 4 (August 2021): 405–16. http://dx.doi.org/10.21273/horttech04773-20.

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Mechanical stimulation to produce stable and high-quality crops under greenhouse conditions is a promising alternative to chemical growth retardants. However, plant tissue damage and the lack of full automatization have been major constraints for large-scale applications. We demonstrate the potential of automated, touch-less, directed air stream application systems to control the plant height and appearance of bellflower (Campanula ‘Merrybell’), creeping inchplant (Callisia repens), and tomato (Solanum lycopersicum ‘Romello’). Plants were cultivated under greenhouse conditions and exposed to regulated air stream stimuli by three different prototype systems. Air stream stimuli of all three prototype systems significantly reduced plant height of all three plant species. Bellflower plants showed a reduction of 24% and tomato plants showed reductions of 26% to 36% compared with the respective control plants. The degree of height growth inhibition in tomato was shown to be predominantly influenced by the stimulus intensity. An air pressure prototype system was successfully implemented in a horticultural company and the height of creeping inchplant could be sufficiently reduced by 20%, on average, throughout 1 year of the experiment compared with untreated controls. Overall, no plant tissue damage of plants treated with the air stream was visible, and no difference in the number of flowers of the bellflower plants treated with the air stream and of the untreated controls was observed.

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Ashley, K. I., D. S. Mavinic, and K. J. Hall. "Oxygenation performance of a laboratory-scale Speece Cone hypolimnetic aerator: preliminary assessment." Canadian Journal of Civil Engineering 35, no. 7 (July 2008): 663–75. http://dx.doi.org/10.1139/l08-011.

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A prototype laboratory-scale Speece Cone hypolimnetic aerator was used to examine the effect of oxygen input rate and outlet port water velocity on oxygen transfer, using four standard units of measure for quantifying oxygen transfer: (i) the oxygen transfer coefficient at 20 °C, KLa20 (h–1); (ii) the standard oxygen transfer rate (SOTR) (g O2·h–1); (iii) the standard aeration efficiency (SAE) (g O2 kW·h–1); and (iv) the standard oxygen transfer efficiency (SOTE) (%). The maximum inlet velocity (i.e., 70 cm·s–1) was only 23% of the recommended design velocity (i.e., 305 cm·s–1), and the two-phase bubble swarm did not properly develop inside the cone, but remained as a gas pocket at the top of the cone, resulting in a drastically reduced bubble surface area to water ratio. Therefore, all of the performance measures from this prototype Speece Cone were much lower than would be expected with the recommended design inlet velocity of 305 cm·s−1. Despite this difference, the system was still capable of oxygen transfer efficiencies of about 61%, under low gas flow rates, which is still higher than any full-lift design hypolimnetic aerator operating on air. Future research efforts are focused on building a pilot-scale Speece Cone, with as close to the correct inlet and outlet velocities, hydraulic residence time, and physical dimensions as possible, such that a two-phase bubble swarm could be generated. Once this experimental data is collected and analyzed, it can be properly compared with predictive models.

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