Passive Principles Research Articles

Recent Advancements in Microfluidic Circulating Tumor Cell Sorting Devices

In recent years, there has been significant advancement in the creation of microfluidic devices for sorting circulating tumor cells (CTCs), which has transformed the field of cancer diagnosis. This study offers a thorough examination of the most recent developments in microfluidic technology created for accurate and effective isolation of CTCs from intricate biological materials. The integration of active and passive techniques on microfluidic systems has resulted in advancements in sensitivity, specificity, and therapeutic relevance. Advanced methods like acoustofluidic and microfluidic dielectrophoresis can be used for specific capture of circulating tumor cells (CTCs), while simpler approaches such as size-based filtering and deterministic lateral displacement are suitable for various sample types. Hybrid methods, which blend the advantages of active and passive principles, have become a potential strategy for enhancing CTC isolation efficiency. These advancements have far-reaching implications for liquid biopsy applications, making it easier to monitor cancer progression, detect it early, and evaluate responses to treatment without intrusive procedures.

Between Chaos and Cosmic Order

In Timaeus (30a ff.), Plato presents matter as a passive principle, inherently predisposed to disorder, subject to mechanistic necessity, and apparently devoid of any volition or predisposition towards the Demiurge. This cosmological framework, however, is not uniformly embraced by Middle Platonists. Instead, three divergent conceptions of matter emerge: one aligned with Plato’s notion of passivity, another in which matter resists the Demiurge with malevolence, and a third where it actively seeks union with the intelligible realm. This study pursues two primary objectives: first, to explore the ontological status and disposition of matter in relation to the intelligible within Middle Platonic thought; second, to elucidate why matter assumes such antithetical attributes.

TiN/acetylene black composite coatings: Enhanced durability and superhydrophobicity for all-day anti-Icing applications

Current advancements in anti-icing coatings emphasize the integration of photothermal, electrothermal, and superhydrophobic features to significantly enhance de-icing efficiency. However, these multifaceted coatings often involve intricate preparation methods and costly materials, making them susceptible to damage and reduced durability. This research aims to overcome these challenges by combining active and passive anti-icing principles to achieve full-time efficient anti-icing. A novel strategy is devised to modify the wettability of epoxy resins by grafting a fluorinated oligomer using a curing agent bridging technique. By utilizing micron-sized Titanium Nitride (TiN) and nanosized Acetylene Black fillers within a fluorine-modified epoxy resin, applied through a simple spray technique, the resulting coating exhibits excellent photothermal, electrothermal, and superhydrophobic properties. Evaluations confirm the coating’s robust mechanical durability for extended operational use and its stabilized effectiveness in photothermal and electrothermal de-icing. Notably, this approach maintains electrical conductivity by eliminating the filler hydrophobic modification, also enhancing the mechanical performance of nanocarbon-based multifunctional anti-icing coatings. Moreover, it simplifies the manufacturing process, reduces cost of coating materials, and enables broad application across various substrate surfaces.

Management of Municipal Waste Storage and Transportation Systems Based on Passive Defense Principles: A Case Study in District 6 of Tehran Municipality, Iran

Management of Municipal Waste Storage and Transportation Systems Based on Passive Defense Principles: A Case Study in District 6 of Tehran Municipality, Iran

Capillary-osmotic wearable patch based on lateral flow assay for sweat potassium analysis

This paper reports a simple, disposable, and wearable patch inspired by lateral flow assay (LFA) that can continuously and non-invasively sample sweat for colorimetric sensing of potassium (K+). K+ is an important biomarker for healthy cardiovascular and neuromuscular functions of the body. Current techniques for K+ sensing in sweat commonly use ion-selective electrodes that require complex fabrication steps, signal drift issues, and active perspiration for continuous operation. Here, the sensor uses passive osmotic-capillary principles to collect sweat from the skin without the need of external power for sampling. A skin-mounted hydrogel patch equilibrated with glucose and glycerin solutions can extract fluid from the skin at rest because of the high osmotic strength of the hydrogel compared to sweat. The gel delivers fluid to a commercial colorimetric assay via a paper strip. The assay contains the reagent dipicrylamine which is selective to K+. On-body human trials prove that these patches function with low sweat volumes (∼2–3 µL) and measure K+ concentration in sweat extracted both during exercise and rest. The sweat potassium concentration is independent of the sweat rate and its magnitude matches that of blood. Such economical patches could open opportunities for at-home or in-field point-of-care (POC) diagnostics.

Zweifach-Fung Microfluidic Device for Efficient Microparticle Separation: Cost-Effective Fabrication Using CO2 Laser-Ablated PMMA.

Microfluidic separators play a pivotal role in the biomedical and chemical industries by enabling precise fluid manipulations. Traditional fabrication of these devices typically requires costly cleanroom facilities, which limits their broader application. This study introduces a novel microfluidic device that leverages the passive Zweifach-Fung principle to overcome these financial barriers. Through Lagrangian computational simulations, we optimized an eleven-channel Zweifach-Fung configuration that achieved a perfect 100% recall rate for particles following a specified normal distribution. Experimental evaluations determined 2 mL/h as the optimal total flow rate (TFR), under which the device showcased exceptional performance enhancements in precision and recall for micrometer-sized particles, achieving an overall accuracy of 94% ± 3%. Fabricated using a cost-effective, non-cleanroom method, this approach represents a significant shift from conventional practices, dramatically reducing production costs while maintaining high operational efficacy. The cost of each chip is less than USD 0.90 cents and the manufacturing process takes only 15 min. The development of this device not only makes microfluidic technology more accessible but also sets a new standard for future advancements in the field.

The impact of thermal mass on envelope heat loss in the caldarium of Yazd's traditional baths

Traditional Iranian bathhouses (hammams) represent remarkable examples of vernacular architecture optimized for thermal performance in hot arid climates. This study quantitatively evaluates and compares multiple passive heating strategies employed in hammams to mitigate envelope heat loss through thermal simulations of two exemplar cases - the Khan and Golshan baths in Yazd.A post-positivist research approach combined physical documentation, computational modeling using DesignBuilder V7.0.1.004 software, and quantitative analysis. Heat transfer through the caldarium (hot room) envelope was simulated sequentially, first without any heat retention strategies, then adding thermal mass, unconditioned buffer spaces, earth-coupling, and finally urban morphology factors.Results indicate thermal mass was the most effective approach in the studied Yazdi hammams, yielding 37.5 % and 37.3 % reductions in winter heat loss compared to 8.4 %, 5.3 %, and 1.8 % from unconditioned zones, earth-sheltering, and integrated compact urban fabric, respectively. Overall, leveraging thermal mass outperformed the combined impact of the other three strategies by over five times for these cases.The quantified insights highlight vernacular passive heating principles extracted from this historic architectural typology that can potentially inform sustainable high-performance building practices for hot arid regions.

Thermal hydraulic characteristic of thermosyphon pressurized with non-condensable gas

Thermosyphon or wickless heat pipe has been applied in many fields of industry due to its high thermal conductance and passive working principle. Many studies have been done to elucidate the complex thermal hydraulic phenomena inside thermosyphon. Parameters such as geometry, type of working fluid, inclination angle of operation, confinement and entrainment have been major focal points in discussion related to thermosyphon research. However, in recent experimental studies, it has been reported that adding non-condensable gas along with working fluid during the initial charging of thermosyphon increase its entrainment limitation. This finding is important, considering some previous studies regard the presence of non-condensable gas as a hinderance on thermosyphon's condenser performance. In this study, experiments were conducted on a pressurized thermosyphon charged with water and argon gas as a non-condensable substance. Observations have been made especially on the case where cooling temperature on the outside of the condenser is far below operation temperature inside thermosyphon. It was found that low thermal conductivity of non-condensable gas causes large temperature gradient along the condenser. For this condition, currently available correlations cannot be applied. Therefore, experiments were required to prove this hypothesis, involving varying amounts of non-condensable gas. These amounts were expressed by the initial pressure values, ranging from 13 kPa to 160 kPa. The analysis of heat transfer in the evaporator and the condenser was conducted using correlations available in the literature. It was found that a new model is required to describe thermal-hydraulic phenomena in the condenser. The model is currently being validated with experimental data and good agreement has been achieved.

Liquid-liquid flow pattern and mass transfer in a rotating millimeter channel reactor

Abstract Currently, microchannels are widely used in liquid-liquid heterogeneous mass transfer systems due to its excellent mass transfer performance. However, because of the passive mixing principle of traditional microchannels, the improvement of mass transfer performance has a bottleneck. This work proposes a novel rotating millimeter channel reactor (RMCR), capable of achieving liquid-liquid heterogeneous mass transfer enhance by centrifugal force. Three typical flow patterns of slug flow, parallel-droplet flow, and parallel flow in the RMCR were observed by high-speed photography technology. The volumetric mass transfer coefficient (K O a) of the RMCR increased with the increase of the total volumetric flow rate and rotational speed (N) increased. Compared with N = 0 r/min, the K O a of the RMCR increases by 61.5 % at 200 r/min, ranging from 0.013 to 0.021 s−1. The RMCR proposed in this work is expected to be applied to the liquid-liquid heterogeneous mass transfer system with high processing capacity and easy plugging.

Optimal Locating of prisons from the perspective of Passive Defense principles and criteria (Case Study: City of Dogonbadan)

Optimal Locating of prisons from the perspective of Passive Defense principles and criteria (Case Study: City of Dogonbadan)

Passivity-Based Tracking Control of a Mobile Manipulator Robot

This work presents a control approach based on the passivity principle, developed to guarantee performance of the application used to track the trajectory of mobile manipulator when disturbed. By exploiting the particularity of the mobile manipulator robots modelling equipped with a nonholonomic mobile base, we present a global control law for the mobile manipulator as a single system. This control allows taking into account the whole system and modifying its dynamics by introducing a highly non-linear regressor matrix to consider uncertainties and modeling constraints. The presented controller is applied to the mobile manipulator robot composed of a manipulator's arm with 2 DDL mounted on a mobile unicycle platform. Simulation tests validate the performance of the proposed approach when external disturbances occur; showing an acceptable performance of the system's stability and validated by exploiting the Lyapunov theory.

All electromagnetic scattering bodies are matrix-valued oscillators

Scattering theory is the basis of all linear optical and photonic devices, whose spectral response underpins wide-ranging applications from sensing to energy conversion. Unlike the Shannon theory for communication channels, or the Fano theory for electric circuits, understanding the limits of spectral wave scattering remains a notoriously challenging open problem. We introduce a mathematical scattering representation that inherently embeds fundamental principles of causality and passivity into its elemental degrees of freedom. We use this representation to reveal strong constraints in the mathematical structure of scattered fields, and to develop a general theory of the maximum radiative heat transfer in the near field, resolving a long-standing open question. Our approach can be seamlessly applied to high-interest applications across nanophotonics, and appears extensible to general classical and quantum scattering theory.

Classifying marine mammals signal using cubic splines interpolation combining with triple loss variational auto-encoder

In practical applications of passive sonar principles for extracting characteristic frequencies of acoustic signals, scientists typically employ traditional time-frequency domain transformation methods such as Mel-frequency, Short time Fourier transform (STFT), and Wavelet transform (WT). However, these solutions still face limitations in resolution and information loss when transforming data collected over extended periods. In this paper, we present a study using a two-stage approach that combines pre-processing by Cubic-splines interpolation (CSI) with a probability distribution in the hidden space with Siamese triple loss network model for classifying marine mammal (MM) communication signals. The Cubic-splines interpolation technique is tested with the STFT transformation to generate STFT-CSI spectrograms, which enforce stronger relationships between characteristic frequencies, enhancing the connectivity of spectrograms and highlighting frequency-based features. Additionally, stacking spectrograms generated by three consecutive methods, Mel, STFT-CSI, and Wavelet, into a feature spectrogram optimizes the advantages of each method across different frequency bands, resulting in a more effective classification process. The proposed solution using an Siamese Neural Network-Variational Auto Encoder (SNN-VAE) model also overcomes the drawbacks of the Auto-Encoder (AE) structure, including loss of discontinuity and loss of completeness during decoding. The classification accuracy of marine mammal signals using the SNN-VAE model increases by 11% and 20% compared to using the AE model (2013), and by 6% compared to using the Resnet model (2022) on the same actual dataset NOAA from the National Oceanic and Atmospheric Administration - United State of America.

Colloquium 3 Commentary on Hayes

Abstract In his paper, Josh Hayes argues that inclination (ῥοπή) is the nature of each element. It is an active and passive principle that explains why the elements move to their proper places. Thus, according to Hayes, by introducing inclination in De Caelo IV 1, Aristotle posits a single explanatory factor that accounts for all elemental motions. By doing so, he answers the question, posed in Physics VIII 4, of what the cause of elemental motion is. In my comments, I will contest these claims. Aristotle’s theory of elemental motion does not rely on a single explanatory factor; yet, it is not, as Hayes claims, incoherent. Instead, the different strands merely reflect the special nature of the elements.

Colloquium 3 Inclination and the Place of the Elements in De Caelo

Abstract In De Caelo III 2, Aristotle observes that each element is determined by an intrinsic principle to move to its proper place: earth downward, fire upward, and water and air to their respective places in the middle. However, how are we to determine the cause of elemental motion? Aristotle admits that this ranks among the most difficult problems (μάλιστα δ’ ἀπορεῖται) as it is directly related to the argument of Physics VIII 4, which defends the view that whatever is in motion is moved by something. The question of how the elements move is not resolved until we are presented with his definition of inclination (ῥοπή) in De Caelo IV 1. Inclination is the nature of each element to move to its proper place. Aristotle concludes that the principle of inclination is a cause of motion continuously orienting the elements toward their proper places by activating that which is potentially heavy or potentially light. In what follows, I shall demonstrate the internal coherence of Aristotle’s natural philosophy by deploying inclination as a principle of motion and rest to define the nature of each element. This account of inclination as a principle of motion is consistent with Aristotle’s definition of nature in Physics II 1. As an active principle of motion, inclination is identified with the activity (ἐνέργεια) of the element enacting and maintaining its own end (ἐντελέχεια) by being at rest in its proper place. As a passive principle of motion, inclination is identified with the passivity of the element to be moved to its proper place by another element insofar as the respective element undergoes generation or substantial change.

Study on nonlinear dynamics characteristics of dual speed dual clutch transmission system based on bond graph

The variable speed transmission system employs compound planetary gear trains and clutches. Compared to traditional aviation transmission systems, the added control parts in the variable transmission system result in a stronger coupling between components and more complex dynamic response characteristics. Modeling using the central mass method is complex and abstract. This study proposes a bond graph-based method for modeling and analyzing the dynamic behavior of the variable transmission system. The transmission system is divided into multiple component-level real-time dynamic models, and obtain a nonlinear multi-energy domain shift dynamic models based on energy flow paths coupling. The mathematical model is numerically solved using the Runge-Kutta method. Simulation results show that there is a delay in the speed response during the shifting process. Further analysis reveals that this “give and take” phenomenon is related to the mechanical structure and passive working principle of the one-way clutch. Subsequently, the time-domain response of the output speed under the hydraulic loading characteristic curves of linear, exponential, S-shaped, and composite functions, as well as the clutch torque, were studied. The impact of different hydraulic loading durations based on the exponential curve on component speed and torque was also analyzed. The simulation results provide a theoretical basis for designing low-shift impact, high-reliability, and high-performance variable transmission systems.

Transient Synchronization Stability of an Islanded AC Microgrid Considering Interactions Between Grid-Forming and Grid-Following Converters

Microgrid has been rapidly developed for the integration of distributed renewable energy, owing to its superiority of flexible operation and high reliability. Without frequency support from the main grid, the microgrid under islanded operating mode is more likely to lose stability in the presence of large-signal disturbances. However, previous studies mainly focus on weak grid conditions and ignore the interaction effects between different-type converters. Therefore, this paper investigates the transient synchronization stability of an islanded AC microgrid considering dynamic interactions between grid-forming and grid-following converters. Firstly, a simplified nonlinear model of the islanded microgrid is established, which reveals the nonlinear interaction and damping impact on system stability. Based on the passivity principle and LaSalle’s theorem, an explicit stability criterion is formulated to reveal the instability mechanism. With the proposed stability criterion, the impacts of different system parameters are analyzed, which points out the direction of parameters optimization to enhance stability. To validate the effectiveness of the proposed method, simulations and experiments are carried out.

Advances on mechanical designs for assistive ankle-foot orthoses.

Assistive ankle-foot orthoses (AAFOs) are powerful solutions to assist or rehabilitate gait on humans. Existing AAFO technologies include passive, quasi-passive, and active principles to provide assistance to the users, and their mechanical configuration and control depend on the eventual support they aim for within the gait pattern. In this research we analyze the state-of-the-art of AAFO and classify the different approaches into clusters, describing their basis and working principles. Additionally, we reviewed the purpose and experimental validation of the devices, providing the reader with a better view of the technology readiness level. Finally, the reviewed designs, limitations, and future steps in the field are summarized and discussed.

Assessing the Architectural Compatibility of Urban Buildings With Passive Defense Principles in Eslamshahr City

Background and objective Urban security is one of the important challenges for urban managers and planners. In this regard, the passive defense approach in urbanization and residential constructions is considered by urban management as a way to cope with natural and man-made disasters and manage the crisis. The present study aims to develop a conceptual model for the architectural compatibility of buildings in Eslamshahr County, Tehran, Iran, with passive defense principles by assessing the compatible and non-compatible elements to provide essential strategies. Method This is a quantitative-qualitative study. The participants were 30 experts in the field of urban security in Eslamshahr. The data analysis was done using statistical tests such as binominal test, one sample T-test, exploratory factor analysis, and strengths, weaknesses, opportunities, and threats (SWOT) technique. Results The results indicated that the constructions in Eslamshahr are not so compatible with the passive defense principles; the level of compatibility was low to moderate. Conclusion The conceptual model was based on four main categories, including stimulating factors, developing factors, leading factors, and supportive factors. The relations between these categories were set according to the structure of a car wheel, which can be the basis for using stable and safe architecture in constructions.

Passive removal of sulphate and heavy metals from acid mine drainage using sewage sludge and fly ash

This study aims to calculate the removal efficiency (%RE) of metals and sulphate and the constant rate of sulphate reduction from acid mine drainage (AMD) based on passive treatment principles named permeable reactive barrier (PRB) in batch test prior column test. Three media mixtures containing a variety of domestic sewage sludge (SE), mess hall compost (CO), cocopeat (CP), and fly ash (FA) were simulated. All reactive materials are solid waste from other operating units. M1 and M2 were contains organic and inorganic waste, M3 was only contain organic waste. The AMD was collected from a copper mining waste rock dump of which contained high sulphate, metals, and low pH. Batch tests were conducted in a series of glass bottles in an anaerobic chamber, and sub-samplings were taken on days 0, 7, 14, and 28. At the end of treatment, it indicated that M1 mixture resulting in the highest sulphate (SO4 2-) removal (44%), highest alkalinity generation of 1431 mg/L (as CaCO3) and %RE of Al, Cd, Co, Cu, Fe, and Zn were expected to be 100%, Ni 82%, Se 57%, and Mn 98%. Additional of FA for treatment such in M1 and M2 releasing more As in the final result compare to M3 that only contain organic substrates. The primary mechanism controlling the reaction from the M1 was a combination of sulphide precipitation enhanced by Sulphate Reducing Bacteria (SRB) activities supported by pH buffering and hydroxide precipitation. The sulphate reduction mechanism assumed to be the first-order reaction with highest rate constants found as 0.0208 d−1 from M1 reactors, 0.0144 d−1, 0.0161 d−1 for M2 and M3 respectively.