Innovative Experimental Setup Research Articles

Micron-scale imaging using bulk ultrasonics.

An extraordinary resolution down to 50 microns is demonstrated for the first time for bulk ultrasonics, using novel micro-fabricated metamaterial lenses. The development and performance of the silicon-based Fabry-Perot type metalenses with an array of 10 micrometre square holes are discussed. Challenges in wave reception are addressed by a custom-developed micro-focal laser with a sub-micron spot size and an innovative experimental set-up together with physics based signal processing. The results provide a pathway for material diagnostics at greater depths with high resolution using micro-metalens-enhanced ultrasound as an alternative to expensive and radiation prone electromagnetic techniques.

Effect of continuous and discontinuous non-proportional loadings on formability of DX54 sheet material

Both continuous and discontinuous non-proportional loadings occur in multi-stage automotive stamping processes. Discontinuous loading is widely studied, but due to requiring sophisticated experimental procedures, continuous loading has been studied less. This study explores the impact of continuous loading on DX54 steel utilising an innovative experimental setup that enabled cruciform samples to undergo uniaxial to biaxial strain path change continuously without unloading. A similar two-stage discontinuous loading from uniaxial to biaxial with unloading in between was generated in DX54 to understand the differences in macro-strain, micro-strain, microstructure, and micro-texture evolution between the continuous and the discontinuous loadings. The stress state of the material during continuous loading was different to that during discontinuous loading. In this study, the occurrence of ‘pseudo-localisation’ was observed during continuous loading, and the observed rotation of high-strain bands differed between continuous and discontinuous loading. The discontinuous loading induced a higher strain, hardening rate, and increased elongation compared to the continuous loading. These results suggest the potential for higher formability during the discontinuous loading compared to the continuous loading.

Constant-curvature bending response of thin glass: Analytical, numerical and experimental study of “clamp-bending” tests

New generation thin, lightweight and damage-resistant glass, having impressively impact resistance and ability to be bent up to small radii, appears to be the optimal material for extremely deformable structural elements. Its structural use and design require an accurate evaluation of its mechanical properties. However, standard methods to test the glass strength, as the Four-Point Bending and the Coaxial Double Ring test, cannot be used for thin glass, due to its high deformability. Here, an innovative test is proposed, consisting into deforming a thin element into a costant-curvature shape, by prescribing a rotation on two opposite edges of a rectangular plate, while allowing the adjustment of the distance between the supporting hinges. This produces a deformation into an arch of a circle and to a constant stress distribution, allowing to determine the thin glass strength with very simple formulas. An innovative experimental setup, recently proposed for twisting tests on thin glass, has been adapted for constant-curvature bending tests, based on the results of both analytical modelling and numerical analyses. This has been used to perform an experimental campaign, comprising 15 destructive tests on chemically tempered thin glass.

Non-conventional resonant behavior of an unconfined magnetic domain wall in a permalloy strip

The resonant dynamic of a magnetic domain wall in a permalloy microstrip has been investigated using an innovative experimental setup that enables a simultaneous measurement of the ferromagnetic resonance and the magnetoresistance. The resonance frequency associated with the presence of the magnetic domain wall increases linearly with the external magnetic field in the range of fields where the domain wall is present in the microstrip. This linear behavior is unusual in a domain wall and not related to the standard resonant modes of a magnetic domain wall, such as breathing, twisting, or translational modes. The slope of this linear dependency is 1.38 GHz/mT, which is an incredibly large value and allows the detection of very small changes in the external magnetic field. This linear behavior opens a path for developing a highly tunable radio frequency oscillator or a magnetic sensing device where the presence of an external field is detected via small variations in the resonant frequency of the domain wall.

Cultural techniques capture diverse phosphate-solubilizing bacteria in rock phosphate-enriched habitats.

Phosphorus (P) deficiency is a common problem in croplands where phosphate-based fertilizers are regularly used to maintain bioavailable P for plants. However, due to their limited mobility in the soil, there has been an increased interest in microorganisms that can convert insoluble P into a bioavailable form, and their use to develop phosphate-solubilizing bioinoculants as an alternative to the conventional use of P fertilizers. In this study, we proposed two independent experiments and explored two entirely different habitats to trap phosphate-solubilizing bacteria (PSBs). In the first experiment, PSBs were isolated from the rhizoplane of native plant species grown in a rock-phosphate (RP) mining area. A subset of 24 bacterial isolates from 210 rhizoplane morphotypes was selected for the inorganic phosphate solubilizing activities using tricalcium phosphate (TCP) as the sole P source. In the second experiment, we proposed an innovative experimental setup to select mycohyphospheric bacteria associated to arbuscular mycorrhizal fungal hyphae, indigenous of soils where agronomic plant have been grown and trapped in membrane bag filled with RP. A subset of 25 bacterial isolates from 44 mycohyphospheric morphotypes was tested for P solubilizing activities. These two bacterial subsets were then screened for additional plant growth-promoting (PGP) traits, and 16S rDNA sequencing was performed for their identification. Overall, the two isolation experiments resulted in diverse phylogenetic affiliations of the PSB collection, showing only 4 genera (24%) and 5 species (17%) shared between the two communities, thus underlining the value of the two protocols, including the innovative mycohyphospheric isolate selection method, for selecting a greater biodiversity of cultivable PSB. All the rhizoplane and mycohyphospheric PSB were positive for ammonia production. Indol-3-acetic acid (IAA) production was observed for 13 and 20 isolates, respectively among rhizoplane and mycohyphospheric PSB, ranging, respectively, from 32.52 to 330.27 μg mL-1 and from 41.4 to 963.9 μg mL-1. Only five rhizoplane and 12 mycohyphospheric isolates were positively screened for N2 fixation. Four rhizoplane PSB were identified as siderophore producers, while none of the mycohyphospheric isolates were. The phenotype of one PSB rhizoplane isolate, assigned to Pseudomonas, showed four additive PGP activities. Some bacterial strains belonging to the dominant genera Bacillus and Pseudomonas could be considered potential candidates for further formulation of biofertilizer in order to develop bioinoculant consortia that promote plant P nutrition and growth in RP-enriched soils.

An innovative experimental device for characterizing the responses of monopiles subjected to complex lateral loading

Offshore wind turbines are usually founded on monopiles. During the operation period, the structure is subjected to complex lateral loading from wind, wave and current. The soils surrounding those monopiles may deform with increasing the number of loading cycles, leading to tilting of the whole structure; hence, it is vital to carry out physical model tests to examine the long-term performance of monopiles. This study proposes an innovative experimental setup for centrifuge modelling of the response of monopiles under complex lateral loading. Hydraulic actuators are adopted to apply lateral loads on model pile, and electrohydraulic servo-valves and associated controllers are used to achieve a closed loop position or load control. A carefully designed spherical hinge and load bars are used to connect the model pile and actuator shafts. This enables that the pile can rotate freely and can move vertically freely. A centrifuge test on a winged monopole subjected to perpendicular lateral loading was carried out at 100g. The experimental results shed light on pile responses in the cyclic loading and constant loading directions.

Dependence of drying rate on interfacial thermal contact conductance in drum drying of thin materials

Drum dryers are widely employed in various industrial fields for their remarkable capability to efficiently dry thin porous materials such as textiles and paper. The heat transfer process in drum drying involves an interaction between the drum surface and the materials being dried. However, measuring interfacial thermal contact conductance during drum drying is very challenging, and little data has been reported in the literature. It is therefore unclear how changes in interfacial thermal contact conductance quantitatively affect drum drying in terms of drying time. We created an innovative laboratory-scale experimental setup designed to measure changes in moisture content of textiles at various contact pressures during drum drying. By combining our experiments with a simple yet effective heat transfer model, we were able to quantify the impact of interfacial thermal contact resistance on drying time. Specifically, in drying tests using thin cotton textiles, the experimental results revealed that when the contact pressure was increased from 120 Pa to 480 Pa, the thermal contact conductance increased by approximately 30% and the drying time decreased by approximately 20%. The outcomes of our study significantly advance the current understanding of drum drying processes and reveal vital insights into techniques for optimizing energy consumption.

(Digital Presentation) A Novel Electrochemical Reactor Design-2

(In this design emphasis is given particularly on the tube types of the secondary winding without much change in the previous description of the reactor)Different kinds of energies such as optical, thermal, mechanical etc. are used for carrying out chemical reactions.The following presentation deals with a simple and an innovative idea of utilization of electromagnetic energy for carrying out chemical reactions.Proposed here is an entirely different electrochemical reactor design with an innovative experimental setup which will give - or rather - is very likely to give interesting results while carrying out chemical reactions. The setup is a modified transformer. Unlike the conventional transformer which has a primary and a secondary coil of insulated copper wire wound on a transformer core; this suggested setup has a primary coil of copper, but the secondary coil is in the form of a tube in which a reaction mixture i.e. the reactants can be introduced as shown in Figure 1. Reactants that have at least some electrical conductivity are preferable. If not, provision can be made by adding compatible additives. On applying an alternating sinusoidal electric current in the primary coil; the reactants will directly receive energy by the phenomenon known as mutual electromagnetic induction from the primary coil which will/or should initiate, accelerate or aid the reaction.In the experimental setup we have:1) A primary coil of copper,2) A secondary coil in the form of a tube to carry the reactants,3) Variable frequency and amplitude of the alternating electric current to be applied to the primary coil,4) Type of waveform from the waveform generator,5) Provision to control the rate of flow of the reactants through the tubular secondary coil.By experimenting using the proposed setup, it is very likely that we well get some primary results. Based on these primary results/observations, the setup then can be further tuned down to get the desired results by choosing:1) Number of turns of the primary coil,2) Number of turns of the secondary tube coil carrying the reactants,3) Deciding the frequency, amplitude and the duration of the alternating electric current to be applied to the primary coil,4) Selecting the waveform from the waveform generator,5) Deciding the rate of flow of the reactants through the tubular secondary coil,6) Deciding the material and properties of the tube used in the secondary winding etc.Simultaneously, ultrasound, UV radiation, temperature (either cooling or heating) etc. can also be thought of as an application on the reactants contained in the secondary tube.A catalyst can be coated or inserted at proper locations and in proper shape inside the secondary tube.Different frequencies in a particular sequence and duration can also be applied at the input.The tube of the secondary may be: Transparent,Electrically non-conducting,Electrically conducting with insulation coating from outside,Or a combination of conducting - non-conducting - again conducting as shown in Figure 2,And of any such combinations using two or more types of tubes mentioned above. Such combinations of multiple tube types may prove to be beneficial (e.g. for simultaneous application of UV radiation through the transparent portion) and can be experimented on.Different types of transformer assemblies with secondary in the form of a tube to contain the chemicals can also be used. For example, multiple winding transformers which have two or more primary or secondary windings allowing for different combinations of voltages and current, three phase transformers etc.The reactor can be used to study various types of parameters in different types of chemical reactions such as:1) The study of frequency dependence on the rate of chemical reactions,2) Estimation of triggering frequencies for breaking of bonds in a reaction,3) The threshold of a chemical reaction in terms of frequency can also be tested by application of a triggering pulse at the input etc.Here we have an unusual secondary in a transformer wherein the secondary is a coil of reactants.Experimental validation of the reactor needs to be done which will require a team of experts in chemistry/electrochemistry, transformer designing etc. On reviewing the abstract, should any scientist or a group if scientists find the design intriguing, they are welcome to conduct further research using the proposed reactor design. A provisional patent has been filed for the same. Figure 1

On the controllability assessment of biofeedback eyeglasses used in Presbyopia treatment

In recent years, hybrid biofeedback systems utilizing user-controlled electrically tunable lenses have emerged as potential treatments for presbyopia. However, the controllability of these systems, closely linked to user adaptability, has received limited attention in the literature due to the challenges associated with obtaining a comprehensive system model. In this study, we present the design, implementation, and validation of an innovative experimental setup aimed at researching and evaluating the controllability of such a biofeedback system. Our setup incorporates a novel low-complexity model, considering the brain, natural lenses (e.g., the crystalline lens), and electrically tunable lenses, to establish a fundamental model for hybrid biofeedback systems. This model is developed based on an analysis of biofeedback systems, geometrical optics, and control theory, facilitating the identification of strategies to decouple system dynamics and enable precise controllability analysis. The proposed experimental setup was validated with volunteers, providing evidence that confirms the reliable operation of the biofeedback system. Our approach encourages a shift from conventional qualitative approaches toward quantitative evaluation of biofeedback devices. The proposed model and experimental setup hold the potential to statistically assess the controllability of hybrid biofeedback systems for correcting presbyopia, paving the way for further advancements in this field.

Characterization of Mechanical and Cellular Effects of Rhythmic Vertical Vibrations on Adherent Cell Cultures.

This paper presents an innovative experimental setup that employs the principles of audio technology to subject adherent cells to rhythmic vertical vibrations. We employ a novel approach that combines three-axis acceleration measurements and particle tracking velocimetry to evaluate the setup's performance. This allows us to estimate crucial parameters such as root mean square acceleration, fluid flow patterns, and shear stress generated within the cell culture wells when subjected to various vibration types. The experimental conditions consisted of four vibrational modes: No Vibration, Continuous Vibration, Regular Pulse, and Variable Pulse. To evaluate the effects on cells, we utilized fluorescence microscopy and a customized feature extraction algorithm to analyze the F-actin filament structures. Our findings indicate a consistent trend across all vibrated cell cultures, revealing a reduction in size and altered orientation (2D angle) of the filaments. Furthermore, we observed cell accumulations in the G1 cell cycle phase in cells treated with Continuous Vibration and Regular Pulse. Our results demonstrate a negative correlation between the magnitude of mechanical stimuli and the size of F-actin filaments, as well as a positive correlation with the accumulations of cells in the G1 phase of the cell cycle. By unraveling these analyses, this study paves the way for future investigations and provides a compelling framework for comprehending the intricate cellular responses to rhythmic mechanical stimulation.

Functional properties and shape memory effect of Nitinol manufactured via electron beam powder bed fusion

Ti-rich Nitinol (NiTi) is characterized by its functional properties to restore its original shape after deformation due to a temperature-induced reversible martensitic phase transition. In this study, dense Ti-rich Nitinol free of cracks is successfully produced by means of Electron Beam Powder Bed Fusion (PBF-EB). The martensitic phase transition behavior of the as-built NiTi parts and powder is analyzed using Differential Scanning Calorimetry (DSC) analysis. To gain a deep understanding of the DSC results, segregation during solidification is thermodynamically studied (CALPHAD). The PBF-EB-fabricated NiTi shows a microstructure containing fine columnar grains and numerous precipitates, whose influence on the tensile properties at room temperature is discussed. Furthermore, the one-way and two-way shape memory effects of PBE-EB-produced NiTi are investigated using an innovative experimental setup based on thermomechanical training.

Innovative experimental setup for the investigation of material models with regard to strain hardening behavior

Sheet metal formed parts are often produced in multistage processes. The multi-directional deformations that occur in this process pose a challenge for sufficiently accurate modeling of the material behavior. In this paper, we present an experimental methodology and its potential that serves as a basis for a comprehensive validation of material models with respect to multi-directional deformation. Therefore, we present the experimental results of pre-strained DP600 specimens, which we afterwards subjected by the MUC-Test. The MUC-Test has already been established as a methodology for validating material models under proportional loading. By using pre-strained specimens, this methodology can be extended to non-linearities in the load history. For the purpose of the paper, we pre-strain the sheet material in three conditions: uniaxial tension, plane strain and equibiaxial tension. Thus, we show that the MUC-Test is suitable for the representation of multi-directional strain histories and useful for comprehensive validation of material models.

The contribution of deeper layers in slow sand filters to pathogens removal

Slow Sand Filtration is popular in drinking water treatment for the removal of a wide range of contaminants (e.g., particles, organic matter, and microorganisms). The Schmutzdecke in slow sand filters (SSFs) is known to be essential for pathogen removal, however, this layer is also responsible for increased head loss. Since the role of deeper layers in bacteria and virus removal is poorly understood, this research investigated the removal of E.coli WR1 and PhiX 174 at different depths of a full-scale SSF. Filter material from top (0–5 cm), middle (5–20 cm) and deep (20–35 cm) layers of an established filter was used in an innovative experimental set-up to differentiate physical-chemical and biological removal processes. In the analysis, we distinguished between removal by biological activity, biofilm and just sand. In addition, we modelled processes by a one-side kinetic model. The different layers contributed substantially to overall log removal of E.coli WR1 (1.4–1.7 log10) and PhiX 174 (0.4–0.6 log10). For E.coli WR1, biological activity caused major removal, followed by removal within biofilm and sand, whereas, removal of PhiX 174 mainly occurred within sand, followed by biofilm and biological activity. Narrow pore radii in the top layer obtained by micro-computed tomography scanner suggested enhanced retention of bacteria due to constrained transport. The retention rates of E.coli WR1 and PhiX 174 in top layer were four and five times higher than deeper layers, respectively (kret 1.09 min−1 vs 0.26 min−1 for E.coli WR1 and kret 0.32 min−1 vs of 0.06 min−1 for PhiX 174). While this higher rate was restricted to the Schmutzdecke alone (top 5 cm), the deeper layers extend to around 1 m in full-scale filters. Therefore, the contribution of deeper layers of established SSFs to the overall log removal of bacteria and viruses is much more substantial than the Schmutzdecke.

Analysis of Influencing Parameters Enhancing the Plucking Efficiency of Piezoelectric Energy Harvesters.

The integration of energy harvesting systems into sensing technologies can result in novel autonomous sensor nodes, characterized by significant simplification and mass reduction. The use of piezoelectric energy harvesters (PEHs), particularly in cantilever form, is considered as one of the most promising approaches aimed at collecting ubiquitous low-level kinetic energy. Due to the random nature of most excitation environments, the narrow PEH operating frequency bandwidth implies, however, the need to introduce frequency up-conversion mechanisms, able to convert random excitation into the oscillation of the cantilever at its eigenfrequency. A first systematic study is performed in this work to investigate the effects of 3D-printed plectrum designs on the specific power outputs obtainable from FUC excited PEHs. Therefore, novel rotating plectra configurations with different design parameters, determined by using a design-of-experiment methodology and manufactured via fused deposition modeling, are used in an innovative experimental setup to pluck a rectangular PEH at different velocities. The obtained voltage outputs are analyzed via advanced numerical methods. A comprehensive insight into the effects of plectrum properties on the responses of the PEHs is attained, representing a new and important step towards the development of efficient harvesters aimed at a wide range of applications, from wearable devices to structural health monitoring systems.

Laser Vibrometry-Based Precise Measurement of Tape-Shaped Tethers Damping Ratio Toward Space Applications

To mitigate the growing problem of space debris, current international guidelines require spacecraft in Low Earth Orbit (LEO) to implement post-mission disposal strategies to be deorbited within 25 years from the end of their operative life. Electrodynamic tethers are an effective and promising option for deorbiting as they do not require fuel consumption. However, the success of this new technology also depends on the dynamic stability of thin tape-shaped tethers during both deployment and deorbiting phases. This is where precise measurement of damping characteristics of thin tape-shaped tethers comes in. This paper presents an innovative experimental setup and analysis methods for precisely measuring the damping ratio of a thin (thickness 50 microns) tape-shaped tether made of PEEK intended for use in electrodynamic tethers applications. To capture longitudinal oscillations during dynamic tests, we employed a laser vibrometer and explored four different methods of experimental data analysis, comparing and describing them in detail in the paper. We also conducted an uncertainty analysis in line with ISO GUM. The experimental results show good agreement among the four methods used to estimate the damping ratio with the most precise method involving nonlinear regression applied to all the experimental data. A Monte Carlo analysis was carried out considering the most significant sources of uncertainty. The smallest uncertainty interval is ±1% of the estimated damping ratio, with a 95% confidence level, using this method.

Experimental and numerical analysis of the convective flow induced over a dry-ice bank with Particle Image Velocimetry

The utilization of carbon dioxide in new technologies opens a wide range of interesting applications which depend strictly upon heat transfer phenomena. The momentum on the deployment of Carbon Capture Utilization and Storage (CCUS) infrastructures will potentially enlarge the diffusion of technologies for the utilization and recycling of CO2. Such applications, however, require appropriate laboratory investigations for a complete characterization of the CO2 thermo-fluid-dynamic behaviour. The safety management of carbon dioxide is important; thus, accurate modelling is needed since solidification and sublimation of dry-ice can be very challenging to predict analytically. One of the dry-ice applications is the utilisation in refrigeration cycles and in novel CO2 heat pump technologies. For this reason, knowledge about the entity of sublimating CO2 from a solid surface is crucial. This work proposes an innovative experimental setup for the measurement of temperature and convective velocity fields in the sublimating phenomenon of CO2 under atmospheric conditions by means of Particle Image Velocimetry (PIV). The experimental results have been compared and validated with numeric CFD models.

An experimental setup for decoupling optical invariants in honeybees’ altitude control

Bees outperform pilots in navigational tasks, despite having 100,000 times fewer neurons. It is commonly accepted in the literature that optic flow is a key parameter used by flying insects to control their altitude. The ambition of the present work was to design an innovative experimental setup that would make it possible to determine whether bees could rely simultaneously on several optical invariants, as pilots do. We designed a flight tunnel to enable manipulation of an optical invariant, the Splay Angle Rate of Change (SARC) and the restriction of the Optical Speed Rate of Change (OSRC) in the optic flow. It allows us to determine if bees use the SARC to control their altitude and to identify the integration process combining these two optical invariants. Access to the OSRC can be restricted by using different textures. The SARC can be biased thanks to motorized rods. This device allows to record bees’ trajectories in different visual configurations, including impoverished conditions and conditions containing contradictory information. The comparative analysis of the recorded trajectories provides first time evidence of SARC use in a ground-following task by a non–human animal. This new tunnel allows a precise experimental control of the visual environment in ecological experimental conditions. Therefore, it could pave the way for a new type of ecologically based studies examining the simultaneous use of several information sources for navigation by flying insects.

Logarithmic trapping and detrapping in β -Ga2O3 MOSFETs: Experimental analysis and modeling

In this paper, we extensively characterize and model the threshold voltage instability in lateral β-Ga2O3 MOSFETs with Al2O3 gate dielectric. Specifically, (i) the results indicate that the threshold voltage instability originates from electron trapping at gate dielectric border traps close to the Al2O3/β-Ga2O3 interface. (ii) Logarithmic kinetics were detected for both stress and recovery by means of a innovative fast-capacitance experimental setup, over more than seven decades of time; (iii) a generalized model, which is capable of accurately reproducing the experimental results, was proposed to explain this trend.

Cyclic Out-of-Plane Behavior of FRCM-Strengthened Masonry Walls

Fiber Reinforced Cementitious Matrix (FRCM) composite materials represent one of the most interesting retrofitting methods for improving the out-of-plane flexural capacity of masonry walls. Despite their use is becoming more and more widespread, the actual knowledge about the out-of-plane behavior of FRCM-strengthened masonry panels needs further improvements, analyzing in particular the effectiveness of the reinforcement under cyclic loads. In this framework, an innovative experimental set-up, capable of applying a vertical axial load and cyclic out-of-plane horizontal forces on full-scale masonry panels, was used for testing walls retrofitted with glass, aramid-glass, basalt and steel fabrics. The presented experimental study is focused on the analysis of the effectiveness of the different FRCM systems, analyzing in detail failure modes, maximum capacity and the potential performance degradation of the strengthened panels under cyclic actions, providing also a useful comparison with the corresponding monotonic results.

Monitoring of in-vitro ultrasonic stimulation of cells by numerical modeling

Ultrasound stimulation of living tissues is a promising technique that can be safely applied for regenerative treatments. However, the ultrasound-induced mechanotransduction is still not well understood because of the large number of parameters involved at different scales and their difficult experimental accessibility. In this context, in-vitro studies may help to gain insight into the interaction between ultrasound and cells. Nevertheless, to conduct a reliable analysis of ultrasound effects on cell culture, the monitoring of the acoustic intensity delivered to the cells is of prime interest. Thanks to the development of an innovative custom experimental set-up inspired from ultrasound stimulation of bone regeneration conditions, major disturbing phenomena such as multiple reflections and standing wave formation inside the Petri dish are eliminated. Thus, the level of ultrasound stimulation, especially, in terms of spatial average temporal average intensity (ISATA), delivered to the cells can be monitored. Then, to properly estimate the level of ultrasound stimulation, a finite element model representing the experimental in-vitro configuration is developed. The numerical model manages on capturing the characteristics of the experimentally measured acoustic intensity distribution as illustrated by the experimental and numerical ISATA values of 42.3 and 45.8 mW/cm2 respectively, i.e. a relative difference of 8%. The numerical model would therefore allow exploring data inaccessible to experimental measurement and parametric studies to be carried out and facilitates the investigation of different virtual experimental configurations.