Experimental Setup Research Articles

Analytical and Experimental Study on a Versatile Landing System with Shock Response Mechanism

This paper introduces a versatile, passive-landing system designed for various landing operations such as planetary exploration missions, emergency landings of unmanned aerial vehicles (UAVs), and so on. The system leverages energy and momentum exchange mechanisms, incorporating two spring units and a detachable flyaway component to ensure smooth and safe landings. Initially, the kinetic energy of the lander is converted into potential energy stored in the spring units. A switch mechanism then releases this stored energy, converting it back into kinetic energy and transferring momentum to the flyaway part. This process effectively suppresses rebound and reduces acceleration, ensuring a soft landing. A key advantage of this mechanism is its high robustness against variations in initial-fall height. The energy stored in the spring units adjusts according to the falling height, enhancing the system adaptability. The system performance is evaluated through one-dimensional simulations to assess rebound height and acceleration, and two-dimensional simulations to evaluate its ability to prevent tip-over. An experimental setup further validates the system-rebound suppression capability. Results from both simulations and experiments confirm the superior system performance in minimizing rebound, reducing acceleration, and preventing rotational motion during landing.

Microplate fluorescence quenching for high throughput screening of affinity constants - Serum albumins and zearalenones case study.

Measurements of changes in fluorescence signal is one of the most commonly applied methods for studying protein-ligand affinities. These measurements are generally carried out using cuvettes in spectrofluorometers, which can only measure one sample at a time. This makes screening procedures for multiple ligands and proteins extremely laborious, as each protein must be measured with multiple ligand concentrations, and usually in triplicate. Moreover, multiple equations exist to extract the affinity constants and other information from the data, and their underlying assumptions are often disregarded. In this study, the affinities of human, bovine and rat serum albumins for the mycotoxin zearalenone and five of its common derivatives were measured in 96-well microplates, allowing quick measurements of multiple samples using less reagent amounts. In comparison to measurements using a cuvette in a spectrofluorometer, the microplate method was shown to reproduce the affinity constants accurately. The results were discussed in terms of common pitfalls regarding experimental setup and available equations to analyze protein-ligand binding in fluorescence quenching assays. The commonly used Stern-Volmer equation was discussed in detail and the results used to show how inaccurate it is when a fluorescent protein-ligand complex is formed, and when other underlying approximations are ignored.

Propagating data without MIMO over a weakly-coupled OAM fiber by multiplexing OAM mode group

Urged by the continually increasing requirement of channel capacity, orbital angular momentum (OAM) has become a promising candidate for extending the multiplexed physical domain, which is compatible with the traditional physical space. However, due to the serious crosstalk among OAM modes and propagation loss, the OAM-based optical fiber communication (OFC) is limited within a shorter scope. A common multiple-input-multiple-out (MIMO) algorithm are usually employed to equalize the multiplexed channels for reducing the crosstalk at the cost of inevitably increasing the complexity of the system. For overcoming the aforementioned issues, a weakly-coupled OAM fiber (WCOF) is designed and manufactured to propagate OAM beams without MIMO, where three OAM mode groups (OMGs) are employed for multiplexing. An experimental setup is also designed and established for validating the feasibility of the proposed WCOF. The captured intensity profiles demonstrate the transmitted OAM beams can be successfully received, and the measured bit-error-rate (BER) distributions show the simulated user data carried by each of three OMGs can be correctly received with/without MDM after the propagation of more than 100 km WCOF when the received power (RP) is set to be greater than −28.33/-27.5 dBm, respectively. Moreover, the measured BERs of OMG1/2/3 are all below the Hard FEC threshold at the C + L waveband, which demonstrates that the proposed scheme can be utilized in the whole C + L waveband. In addition, the influences of data velocity and WCOF length on the BER are also exploded, which shows that the detected BER performance declines mildly as the data velocity increases from 10 to 40 Gbit/s, and the measured BER performance also slightly degrades as the WCOF length increases from 100 to 140 km. Therefore, the proposed scheme can be potentially utilized without MIMO for long-haul OFC with higher channel capacity.

CIMIL-CRC: A clinically-informed multiple instance learning framework for patient-level colorectal cancer molecular subtypes classification from H&E stained images.

Treatment approaches for colorectal cancer (CRC) are highly dependent on the molecular subtype, as immunotherapy has shown efficacy in cases with microsatellite instability (MSI) but is ineffective for the microsatellite stable (MSS) subtype. There is promising potential in utilizing deep neural networks (DNNs) to automate the differentiation of CRC subtypes by analyzing hematoxylin and eosin (H&E) stained whole-slide images (WSIs). Due to the extensive size of WSIs, multiple instance learning (MIL) techniques are typically explored. However, existing MIL methods focus on identifying the most representative image patches for classification, which may result in the loss of critical information. Additionally, these methods often overlook clinically relevant information, like the tendency for MSI class tumors to predominantly occur on the proximal (right side) colon. We introduce 'CIMIL-CRC', a DNN framework that: (1) solves the MSI/MSS MIL problem by efficiently combining a pre-trained feature extraction model with principal component analysis (PCA) to aggregate information from all patches, and (2) integrates clinical priors, particularly the tumor location within the colon, into the model to enhance patient-level classification accuracy. We assessed our CIMIL-CRC method using the average area under the receiver operating characteristic curve (AUROC) from a 5-fold cross-validation experimental setup for model development on the TCGA-CRC-DX cohort, contrasting it with a baseline patch-level classification, a MIL-only approach, and a clinically-informed patch-level classification approach. Our CIMIL-CRC outperformed all methods (AUROC: 0.92±0.002 (95% CI 0.91-0.92), vs. 0.79±0.02 (95% CI 0.76-0.82), 0.86±0.01 (95% CI 0.85-0.88), and 0.87±0.01 (95% CI 0.86-0.88), respectively). The improvement was statistically significant. To the best of our knowledge, this is the best result achieved for MSI/MSS classification on this dataset. Our CIMIL-CRC method holds promise for offering insights into the key representations of histopathological images and suggests a straightforward implementation.

Intensity corrections for grazing-incidence X-ray diffraction of thin films using static area detectors

Grazing-incidence X-ray diffraction (GIXD) is the technique of choice for obtaining crystallographic information from thin films. An essential step in the evaluation of GIXD data is the extraction of peak intensities, as they are directly linked to the positions of individual atoms within the crystal unit cell. In order to obtain reliable intensities independent of the experimental setup, a variety of correction factors need to be applied to measured GIXD raw data. These include the polarization of the incident beam, solid-angle variations, absorption effects, the transmission coefficient and the Lorentz correction. The aim of this work is to provide a systematic compilation of these intensity corrections required for state-of-the-art GIXD setups with static area detectors. In a first step, analytical formulae are derived on the basis of theoretical considerations. The obtained intensity corrections are then applied to measured GIXD raw data from samples with different textures, including a single crystal and thin films containing either randomly distributed or oriented crystallites. By taking advantage of the symmetries inherent in the different types of textures, integrated peak intensities are determined, and these are compared with intensities calculated from single-crystal diffraction data from the literature. Accurate intensity corrections promise an improved quality of crystal structure solution from thin films and contribute to achieving accurate phase and texture quantifications from GIXD measurements.

Chlorhexidine-loaded microneedles for treatment of oral diseases.

Chlorhexidine (CHX) is a gold standard therapeutic agent against clinical oral pathogens. However, its oral use is limited due to unpleasant taste, alteration in taste buds, staining of teeth and mucous membranes. Therefore, CHX-loaded PLGA microneedles (MNs) were fabricated for local and controlled release in the oral cavity, using a casting mold method. The MNs were well-formed with sharp MN tips and flat baseplates, showing quadrangular pyramidal shapes with average needle height and base width of about 500 and 200µm, respectively. CHX was successfully incorporated into the PLGA-based MNs, exhibiting high encapsulation efficiency. CHX-PLGA MNs were further characterized in terms of ATR-FTIR and DSC, indicating intermolecular interactions between CHX and PLGA. In vitro CHX release exhibited an initial burst release within the first 24h, accompanied by a slower release rate, reaching cumulative release of ca. 56% after 10days. The antibacterial effect of CHX-PLGA MNs on Streptococcus mutans (S. mutans) was evaluated using different techniques. In agar diffusion assay, the MNs displayed sustained antimicrobial activity over 8days, while they significantly reduced the bacterial growth of S. mutans on the first 4days in a planktonic experimental setup. No antibacterial effect was recorded for the blank PLGA MNs that served as a control group. Interestingly, CHX-PLGA MNs eliminated biofilm formation and metabolic activity for 3days compared with biofilm formed in the presence of blank MNs. Then, a rebound effect was recorded. A weak antibiofilm effect and anti-metabolic activity was observed when MNs tested against pre-formed biofilm. Taken together, CHX-PLGA MNs hold promise as a viable delivery modality for localized and sustainedantimicrobial activity in the oral cavity. Further research is required to optimize the formulation and assess efficacy and safety in clinical settings.

An experimental setup to study the collision force between brittle impacting bodies

A new experimental setup to study the interaction between two brittle bodies which can experience crushing, comminution or fragmentation during impact is herein presented. The system consists of a free falling body and an instrumented impacted plate, onto which an accelerometer is installed, lying on three force ring cells. The recorded acceleration is decomposed into Intrinsic Mode Functions thanks to a Variational Mode Decomposition technique to obtain relevant time-histories associated with specific vibration frequencies. The mass participating to each mode is obtained by comparing the discrete Fourier transforms of force and acceleration. Finally, the adoption of a high-speed camera provides additional insights into the interaction, in particular when non-spherical bodies are considered. The results of a small experimental campaign serving as a benchmark are presented and discussed.

Mixing characteristics and co-flow behavior in interactive cascade ventilation: An Experimental Approach

Achieving optimal indoor air quality that is both healthy and comfortable remains a persistent pursuit. Interactive cascade ventilation (ICV) has demonstrated remarkable performance, harnessing a temperature gradient to reverse the direction of buoyancy flux. The aim of this study is to investigate the mixing characteristics and co-flow behavior of ICV. Experiments, informed by Abramovich's theory and the principles of similarity, are conducted using a scaled-down experimental setup. The research results indicate that varying the temperature difference between the upper and lower jets from 2°C to 7°C significantly influences the deflection angle. Notably, the lower jet exhibits a more pronounced decrease of 52%, suggesting that the warmer lower jets effectively uplift the cooler upper jets. It can counteract their descent, optimizing the use of cool air in occupied spaces. Additionally, analysis of different velocity ratios reveals a reduction in the deflection angle from 12.69° to 5.57° as the velocity ratio increases from 0.5 to 0.81. A modified jet equation has been derived, which delineates the central path of the jet trajectory. The insights obtained from this research serve to bolster the theoretical framework for optimizing critical supply air parameters within the ICV system, thereby significantly enhancing its ventilation performance. These findings elucidate the underlying mechanisms of ICV, leading to a more profound understanding of its operational dynamics.

Experimental Research of Heating Characteristics on An Air Source Heat Pump System with Capillary Direct Floor Radiant

A new-type air source heat pump system with capillary direct floor radiant (ASHPCFR) was proposed, in which the vapor refrigerant condensed directly in the capillary under the floor to heat the room. Theoretical calculation of heat transfer in the capillary floor was conducted. The results indicated that the optimal capillary spacing should be 100 mm and it was best for a thickness smaller than 60 mm with the floor cement layer. An experimental apparatus for the ASHPCFR system was developed, and its low-temperature heating process and normal heating process were experimentally investigated. Experimental results showed that when the outdoor temperature was -5 °C, the indoor air temperature reached 20 °C after 120 minutes of running, while the temperature difference of a 20 mm thick cement floor could reach 1.73 °C and its maximum temperature could reach 27.5 °C. When the outdoor temperature was -10 °C, the system heating COP was stable at 3.06.

Insights into stability and control of the powerslide motion with variable drive torque distribution – applied to a driver assistance system

In this study, a theoretical investigation of the steady-state powerslide motion, or drift, is conducted to gain insight into the influence of the total drive torque and front/rear axle drive torque distribution on the powerslide dynamics of an all-wheel drive vehicle, including the case of a rear-wheel drive vehicle. The steady-state conditions and stability properties are derived, and different actuator inputs, i.e. steering angle, total drive torque and drive torque distribution, to stabilise the unstable powerslide motion are analysed and discussed with respect to different control strategies. The results indicate that the drive torque distribution is an effective control input for stabilisation and can be superior to the total drive torque input. The powerslide cannot be stabilised for particular conditions with the total drive torque input at fixed drive torque distribution. Based on these findings, a driver assistance system is presented that allows the human driver to track a desired circular path only by steering commands. The powerslide motion is stabilised automatically by a controller acting on the total drive torque and on the drive torque distribution if favourable. The characteristics, limitations in dynamics and reactions of a human driver are considered by introducing a virtual test driver model in a simulation environment. The successfully performed powerslide is shown in simulation with a basic vehicle model and in an experimental setup with a test vehicle.

Amplitude and Phase Imaging of CW-THz Waves Using a Photomixing System with Coherent Detection

Continuous-Wave Terahertz (CW-THz) phase and amplitude imaging provides valuable insights into the interaction between THz waves and matter, particularly in low-absorption materials. This information is also essential for enhancing CW-THz beam profiling, a critical aspect in the design of free-space THz devices. Hereby, we introduce a single-pixel THz amplitude and phase imaging technique based on frequency scanning and fringe analysis, incorporated into a straightforward experimental setup. We validate the usefulness of the proposed approach by demonstrating two representative case studies. The first is a 3-D measurement of the amplitude and phase profile of a THz wave that is transmitted through a 3-D printed metalens. The second is beam profiling of a THz beam emitted from a photomixer antenna. In both cases, our results are in excellent agreement with previous predictions and validate the usefulness of this imaging technique. As such, we believe that the demonstrated approach will provide an important tool in the quest for establishing THz as an important method for a myriad of applications, including imaging, range finding and metrology.

An EM algorithm for fitting matrix-variate normal distributions on interval-censored and missing data

Matrix-variate distributions are powerful tools for modeling three-way datasets that often arise in longitudinal and multidimensional spatio-temporal studies. However, observations in these datasets can be missing or subject to some detection limits because of the restriction of the experimental apparatus. Here, we develop an efficient EM-type algorithm for maximum likelihood estimation of parameters, in the context of interval-censored and/or missing data, utilizing the matrix-variate normal distribution. This algorithm provides closed-form expressions that rely on truncated moments, offering a reliable approach to parameter estimation under these conditions. Results obtained from the analysis of both simulated data and real case studies concerning water quality monitoring are reported to demonstrate the effectiveness of the proposed method.

Experimental and GEANT4 Simulated FEPE of NaI(Tl) Detector for Linear Sources.

The current study investigated the geometry, design and solid angle impacts on full energy peak efficiency (FEPE) of NaI(Tl) detectors for a line source. A line source is fabricated using 99mTc solution filled in a borosilicate glass tube of inner diameter 3 mm, tube wall thickness 2.5 mm and length 12.7 cm. The FEPE is measured for the fabricated linear source using 2''⨯2'' NaI(Tl) cylindrical detector at various source-detector distances. The experimental setup is simulated in GEANT4 and the computed FEPE values are compared with experimental values. The absolute error of 5% is observed between computed and measured FEPE values. Utilizing the advantages of MC simulations, the impact of numerous source parameters such as source length, diameter, source-detector distance, glass tube thickness and lead shield effects on FEPE are investigated to optimize the fabrication process of linear sources. A case study for current investigation has been analyzed by considering absolute FEPE of the NaI(Tl) system for a syringe filled with radioactive solution. This study provides an insight for the fabrication of standard linear sources by analyzing different source parameters and hence, may serve as a guideline to prepare standard linear sources for the calibration of radiation detectors.

Boosting human immunology: harnessing the potential of immune organoids.

Studying the human immune system in vivo is challenging and often not possible. Therefore, most human immunology studies have been predominantly confined to peripheral blood analyses, which by themselves have inherent limitations, as many immune reactions take place within tissues. For example, potent antibody responses that contribute to fighting infections and provide protection following vaccination require cellular interactions between B cells and T cells in specialized micro-anatomical structures called germinal centers, which are found in secondary lymphoid organs such as spleen, lymph nodes, and tonsils. Thus, there is a clear demand for novel enhanced experimental systems that faithfully recapitulate the intricate dynamics of the human immune system as much as possible. In this review, we discuss recent advances in versatile human tonsil/adenoid tissue-based ex vivo immune organoid cultures as well as related cancer and autoimmunity-focused experimental setups. These systems have been implemented as translational immunology platforms for in-depth analyses of human B and T cell-mediated immune responses, thereby facilitating mechanistic studies as well as drug and vaccine testing in a human-first approach.

α-Al2O3 Functionalized with Lithium Ions Especially Useful as Inert Catalyst Bed Supports

The alumina, in the form of α-Al2O3 tabular balls, considered in this study is a high-purity form of aluminum oxide that has been fired at high temperatures (well above 1900 °C), virtually removing porosity. However, the purity and inertness of the surface of the Al2O3 tabular balls minimize the catalytic activity, which is why lithium doping was tried. Thus, the target of this study was the effect of doping with lithium ions in some tabular balls of Al2O3 (the crystalline structure is corundum) on the improvement of the catalytic properties of alumina. This study examined the impact of a lithium catalyst on the combustion of various fuels within a porous inert medium (PIM) burner. This study specifically compared low calorific gaseous fuel (e.g., biogas) combustion in a PIM burner with and without the lithium catalyst. The experimental setup comprised a gas preparation unit for mixing CNG and CO2 to simulate biogas and a PIM burner. The PIM burner comprised Al2O3 spheres (13 mm diameter, 45% porosity) in a random packing configuration. Three fuels, varying in composition and lower heating value (LHV ranging from 20.771 to 27.695 MJ/m3), were combusted at air ratios ranging from 1.67 to 1.79. The results indicated that the catalyst increased peak combustion temperatures by 23.2 °C to 51.4 °C, depending on the fuel type and air ratio. Significantly higher carbon monoxide (CO) concentrations were observed without the catalyst, particularly with fuel type F1, while nitrous oxide (NOx) levels remained consistently low. Upstream flame propagation was observed in the presence of the catalyst. These findings demonstrate the potential of lithium catalysts to enhance combustion stability and reduce emissions in porous media combustion burners. Following these studies, it can be stated that Li(I) has the role of promoter of the catalytic process.

Numerical Investigation of the Effect of the Mushy Zone Parameter and the Thermal Properties of Paraffin‐Based PCMs on Solidification Modeling Under T‐History Conditions

ABSTRACTPhase change materials (PCMs) are widely used in various critical applications because of their capacity to store thermal energy and regulate temperature effectively. A review of the literature on PCM solidification and melting simulations reveals that the accuracy of these simulations is highly dependent on the input parameters and underlying assumptions used in the software. Among the key factors influencing precise simulation results are the parameter of mushy zone () and the thermal properties of the material. This study numerically investigated the impact of the and thermal properties on the solidification behavior of a paraffin in the test tube under T‐history conditions. The analysis was conducted using the commercial CFD software ANSYS Fluent and the enthalpy‐porosity method is applied to simulation the solidification process. To accurately reflect the conditions of the T‐history experiment, radiative heat transfer between surfaces was employed for the boundary conditions, ensuring a realistic representation of the experimental setup. An evaluation of four thermal properties—thermal conductivity, density, latent heat, and specific heat—indicates that while an increase in latent heat, density, and specific heat slows down the rate of solidification, an increase in thermal conductivity has the opposite effect, accelerating the solidification process. The results further emphasize that selecting an appropriate value for is crucial for achieving accurate solidification simulations. Increasing from to enhanced the prediction accuracy of the solidification time by 10%. Additionally, the mushy zone parameter significantly affects the shape and progression of solidification. As increases, solidification in the lower layers decreases, concentrating the process more in the layers adjacent to the cold wall.

Vetiver (Vetiveria Zizanioides) As Phytoremediator on Chromium and Nickel Uptake in Lowland Rice Soils Affected by Mining Activities

The use of vetiver (Vetiveria zizanioides) is one of a few plant species meeting all the criteria required for phytoremediation. However, very limited studies have been done to use this plant as a phytoremediator in lowland rice soils. The study was conducted to determine the effect of phytoremediation using different time durations of vetiver grown for 3 and 8 months in the field and to evaluate the accumulation and translocation of Cr and Ni at various growth stages of the crop after planted with 3 months of vetiver. The field experimental set-up was conducted for two cropping seasons. Results revealed that vetiver had a Bio-accumulation factor of 0.97 for Cr and 1.07 for Ni after 3 months of growth and 1.48 for Cr and 1.38 for Ni after 8 months, indicating a higher concentration of Cr and Ni in the plant than in the soil. The translocation factors at both 3 and 8 months were below 0.2 mg kg -1 suggesting that vetiver accumulates Cr and Ni in the roots and very small amount is translocated to the shoots, making the plant safe for forage purposes. The Cr and Ni content in rice grains after planting the area with 3 months vetiver, were efficiently reduced to below detection limits.

Energy-exergy and enviro-economic analysis of water-cooled brazed plate building-integrated condenser for cooling appliances in dwellings.

Globally, domestic refrigerators account for over 13% of the total energy consumption in residential buildings. The brazed plate water-cooled condenser (BPWCC) is compact in size and an attractive option to reduce the energy consumption of refrigerators using domestic water tanks. This study evaluated the performance of a household refrigerator with a secondary refrigerant calorimeter and BPWCC, using an appropriate experimental setup. Water storage tanks with capacities of 750l, 1000l, and 2000l supplied cooling water to BPWCC. The study evaluated how well the modified domestic refrigerator (MDR) worked with R134a and a blend of R290 and R600a (54.8:45.2), using 108g and 50g of charge, respectively. When the MDR was charged with the R290/R600a blend, its COP, exergy efficiency, per-day energy consumption, and total equivalent warming impact were 0.93-1.18, 24-24.8%, 1.28-1.4 kWh, and 5019, respectively. BPWCC's exergy efficiency went up by 25-55% when the condensing temperature went down, and it used 11.5-27% less energy per day than air-cooled condensers. Besides reducing the cost rate by 32-37%, the modified system showed a payback period below 3years. However, to mature the proposed system, future research must focus on several issues related to the integration of the domestic water system with the BPWCC.

Study into surface integrity aspects in single point incremental forming of AA 7079 sheet: experimental investigation and evolutionary parametric optimization

ABSTRACT Aluminum alloys have been used for the Single Point Incremental Forming (SPIF) process due to their formability, corrosion resistance, less weight and its isotropic mechanical properties. The proposed research work aims to experimentally investigate the optimisation of the process inputs affecting the quality of the SPIF incrementally formed surface. The experimentation was performed to optimise parameters under varying conditions, focusing on various process factors. The surface roughness (SR) has been found most significantly affected by the tool diameter, followed by vertical step size, side wall angle, feed rate, and rotational spindle speed. Experimentation result shows the outstanding values of the experimental set-up for surface finish found on the base of the ANOVA at 70° cone angle under the test setting of a TD of 13.0 mm, a VSS of 0.50 mm, RSS of 1000 rpm, and a FR of 2500 mm/min. The parametric optimisation for SR with Desirability approach, TLBO (Teacher learner-based optimisation), and ACO (ant colony optimisation) methods has been attempted, out of which the best optimum value (with ACO) for SR was achieved as 0.162 µm at the optimal parametric settings of TD = 14.75 mm, VSS = 0.660 mm, RSS = 521.70 rpm, FR = 2760 mm/min, and WA = 76.56°.

Survey-Inspired Philosophy and Judging About Counterfactual Reference

ABSTRACT When discussing around his Gödel-Schmidt case, Kripke implicitly invoked our intuitive judgements about reference to argue against descriptivism on proper names. E. Machery and some collaborators have used survey data to attack Kripkean theses. In this article, I raise a new objection to this kind of criticism of anti-descriptivism. The participants in the surveys were presented with two possible answers to a determinate question. I show that the answer that Machery and his collaborators presuppose to be descriptivist is in fact ambiguous, and it can be interpreted according to a reading that is perfectly compatible with anti-descriptivism. To argue for this thesis, I describe two ambiguities in the experimental setup that inspires their claims. Both ambiguities relate to the distinction between counterfactual and actualist readings of certain hypotheses, questions or statements.