Search Results (393)

A concept towards current measurement in low and medium voltage power distribution networks is presented. The concentric magnetic field around the current-carrying conductor should be measured using a nitrogen-vacancy quantum magnetic field sensor. A bottleneck in current measurement systems is the readout electronics, which are usually based on optically detected magnetic resonance (ODMR). The idea is to have a hardware that tracks up to four resonances simultaneously for the detection of the three-axis magnetic field components and the temperature. Normally, expensive scientific instruments are used for the measurement setup. In this work, we present an electronic device that is based on a Zynq 7010 FPGA (Red Pitaya) with an add-on board, which has been developed to control the excitation laser, the generation of the microwaves, and interfacing the photodiode, and which provides additional fast digital outputs. The T1 measurement was chosen to demonstrate the ability to read out the spin of the system. Full article

Background and Objective: Temperature management is key for reliable operation of permanent magnet synchronous motors (PMSMs). The lumped-parameter thermal network (LPTN) is fast and interpretable but struggles with nonlinear behavior under high power density. We propose OLTEM, a physics-informed deep model that combines LPTN with a thermal neural network (TNN) to improve prediction accuracy while keeping physical meaning. Methods: OLTEM embeds LPTN into a recurrent state-space formulation and learns three parameter sets: thermal conductance, inverse thermal capacitance, and power loss. Two additions are introduced: (i) a state-conditioned squeeze-and-excitation (SC-SE) attention that adapts feature weights using the current temperature state, and (ii) an enhanced power-loss sub-network that uses a deep MLP with SC-SE and non-negativity constraints. The model is trained and evaluated on the public Electric Motor Temperature dataset (Paderborn University/Kaggle). Performance is measured by mean squared error (MSE) and maximum absolute error across permanent-magnet, stator-yoke, stator-tooth, and stator-winding temperatures. Results: OLTEM tracks fast thermal transients and yields lower MSE than both the baseline TNN and a CNN–RNN model for all four components. On a held-out generalization set, MSE remains below 4.0 °C² and the maximum absolute error is about 4.3–8.2 °C. Ablation shows that removing either SC-SE or the enhanced power-loss module degrades accuracy, confirming their complementary roles. Conclusions: By combining physics with learned attention and loss modeling, OLTEM improves PMSM temperature prediction while preserving interpretability. This approach can support motor thermal design and control; future work will study transfer to other machines and further reduce short-term errors during abrupt operating changes. Full article

Ant venoms are rich sources of bioactive molecules, including peptide toxins with potent and selective activity on ion channels, which makes them valuable for pharmacological research and therapeutic development. Voltage-dependent potassium (Kv) channels, critical for regulating cellular excitability or cell cycle progression control, are targeted by a diverse array of venom-derived peptides. This study focuses on MYRTX_A4-Tb11a, a peptide from Tetramorium bicarinatum venom, which was previously shown to have a strong paralytic effect on dipteran species without cytotoxicity on insect cells. In the present study, we show that Tb11a exhibited no or low cytotoxicity toward mammalian cells either, even at high concentrations, while electrophysiological studies revealed a blockade of hKv1.3 activity. Additionally, Ta11a, an analog of Tb11a from the ant Tetramorium africanum, demonstrated similar Kv1.3 inhibitory properties. Structural analysis supports that the peptide acts on Kv1.3 channels through the functional dyad Y21-K25 and that the disulfide bridge is essential for biological activity, as reduction seems to disrupt the peptide conformation and impair the dyad. These findings highlight the importance of three-dimensional structure in channel modulation and establish Tb11a and Ta11a as promising Kv1.3 inhibitors. Future research should investigate their selectivity across additional ion channels and employ structure-function studies to further enhance their pharmacological potential. Full article

The search for substances that increase the immunity of bees is becoming a necessity in the era of various environmental threats and the declining immunocompetence of these insects. Therefore, we tested the biological and physicochemical properties of 7-diethylamino-4-hydroxycoumarin (7DOC). In a cage test, two groups of bees were created: a control group fed with sugar syrup and an experimental group fed with sugar syrup with the addition of 7DOC. In each group, the longevity of the bees was determined and the protein concentrations and antioxidant activities in the bees’ hemolymph were determined. The bees fed with 7DOC lived 2.7 times longer than those in the control group. The protein concentrations and activities of SOD, CAT, GPx and GST, as well as the TAC levels, were significantly higher in the hemolymph of the supplemented workers. To confirm these potent biological properties of 7DOC, the UV-Vis spectra, emission and excitation of fluorescence, synchronous spectra and finally the fluorescence lifetimes of this compound were measured using the time-correlated single photon counting method, in various environments differing in polarity and in the environment applied in bee research. This compound was shown to be sensitive to changes in solvent polarity. The spectroscopic assays were complemented with crystallographic tests of the obtained monocrystals of the aforementioned compounds, which attested to the aggregation effects observed in the spectra measurements for the selected coumarin. The research results confirm that this compound has the potential to be implemented in apiary management, which will be our application goal, but further research into apiary conditions is required. Full article

The balance between cortical excitation and inhibition (E/I balance) in the cerebral cortex is critical for cognitive processing and neuroplasticity. Modulation of this balance has been linked to a wide range of neuropsychiatric and neurodegenerative disorders. The human visual system has well-differentiated magnocellular (M) and parvocellular (P) pathways, which provide a useful model to study cortical excitability using non-invasive visual flicker stimulation. We present an Arduino-driven non-image forming system to deliver controlled flickering light stimuli at different frequencies and wavelengths. By triggering the critical flicker fusion (CFF) frequency, we attempt to modulate the M-pathway activity and attenuate P-pathway responses, in parallel with induced optical scattering. EEG recordings were used to monitor cortical excitability and oscillatory dynamics during visual stimulation. Visual stimulation in the CFF, combined with induced optical scattering, selectively enhanced magnocellular activity and suppressed parvocellular input. EEG analysis showed a modulation of cortical oscillations, especially in the high frequency beta and gamma range. Our results support the hypothesis that visual flicker in the CFF, in addition to spatial degradation, initiates detectable neuroplasticity and regulates cortical excitation and inhibition. These findings suggest new avenues for therapeutic manipulation through visual pathways in diseases such as Alzheimer’s disease, epilepsy, severe depression, and schizophrenia. Full article

Ensuring the safety of large spherical water storage tanks in seismic environments is critical. Therefore, this study proposed a vibration control device applicable to general spherical water tanks. By utilizing the upper interior space of a spherical tank, a novel tuned mass damper (TMD) system composed of a mass block and four elastic springs was proposed. To enable practical implementation, the vibration control mechanism and tuning principle of the proposed TMD were examined. Subsequently, an experimental setup, including the spherical water tank and the TMD, was developed. Subsequently, shaking experiments were conducted using two types of spherical tanks with different leg stiffness values under various seismic waves and excitation directions. Shaking tests using actual El Centro NS and Taft NW earthquake waves demonstrated vibration reduction effects of 34.87% and 43.38%, respectively. Additional shaking experiments were conducted under challenging conditions, where the natural frequency of the spherical tank was adjusted to align closely with the dominant frequency of the earthquake waves, yielding vibration reduction effects of 18.74% and 22.42%, respectively. To investigate the influence of the excitation direction on the vibration control performance, shaking tests were conducted at 15-degree intervals. These experiments confirmed that an average vibration reduction of more than 15% was achieved, thereby verifying the validity and practicality of the proposed TMD vibration control system for spherical water tanks. Full article

Traditional PMUT ultrasonic ranging systems usually possess a large measurement blind area under the integrated transmit–receive mode, dramatically limiting its distance measurement in confined spaces, such as when determining the clearance of large bearing components. Here, a broadband PMUT rangefinder was designed by integrating six types of different cells with adjacent resonant frequencies into an array. Through overlapping and coupling of the bandwidths from the different cells, the proposed PMUTs showed a wide –6 dB fractional bandwidth of 108% in silicon oil. Due to the broadening of bandwidth, the device could obtain the maximum steady state with less excitation (5 cycles versus 14 cycles) and reduce its residual ring-down (ca. 6 μs versus 15 μs) compared with the traditional PMUT array with the same cells, resulting in a small blind area. The pulse–echo ranging experiments demonstrated that the blind area was effectively reduced to 4.4 mm in air or 12.8 mm in silicon oil, and the error was controlled within ±0.3 mm for distance measurements up to 250 mm. In addition, a specific ultrasound signal processing circuit with functions of transmitting, receiving, and processing ultrasonic waves was developed. Combining the processing circuit and PMUT device, the system was applied to determine the axial clearance of the main bearing in a tunneling machine. This work develops broadband PMUTs with a small blind area and high resolution for distance measurement in narrow and confined spaces, opening up a new path for ultrasonic ranging technology. Full article

Dicke superradiance, a single-mode burst of radiation emitted by an ensemble of two-level atoms, has garnered tremendous attention within the physics community. Its extension to multi-level systems introduces additional degrees of freedom, such as mode-selective control over well-known Dicke superradiant behaviors. However, previous work on the extension to two-mode superradiance in three-level atoms has been largely overlooked for over five decades. In this study, we revisit the two-mode superradiance model for a Λ-type three-level system, where two modes couple to a common excited state and two separate lower levels, offering new insights. For the first time, we obtain exact numerical solutions of the two-mode rate equations for this model. We analyze the temporal evolution of two-mode intensities, superradiance time delays, and quantum noise in the time domain as the number of atoms varies. We believe this work will enable external mode-selective control over superradiance processes—a capability unattainable in the single-mode case. Full article

High-rise industrial buildings are particularly susceptible to vibration-induced comfort issues, which can negatively impact both the health and productivity of workers and office staff. Unlike most existing studies that focus on local structural components, this study proposes and validates a wave propagation analysis (WPA) method to predict peak accelerations of the floor caused by excitations located on different floors. The method is validated through on-site vibration tests conducted on a high-rise industrial building with shared factory and office space. A simplified regression-based propagation equation is further developed to facilitate practical design applications. The regression parameters are fitted using theoretical calculation results, enabling rapid prediction of peak acceleration responses on the same or different floors. To enhance vibration control, tuned mass dampers (TMDs) are installed on selected floors, and additional tests are conducted with the TMDs activated. An insertion loss-based correction is introduced into the WPA framework to account for the TMD’s frequency-dependent attenuation effects. The extended method supports both accurate prediction of vibration reduction and optimisation of TMD placement across multiple floors in high-rise industrial buildings. Full article

Hybrid excited machines are strong competitors for application in hybrid/full electric vehicles due to their high torque density and strong air gap field-regulating capability. Similar to armature back-EMF, back-EMF also exists in the field windings of hybrid excited machines. However, the existence of field back-EMF is harmful to the safe and stable operation of machine systems, e.g., lower efficiency, higher torque ripple, reduced control performance, etc. In this paper, the influence of the hybridization ratio k, i.e., the ratio of the field winding slot area to the total field slot area, on the field back-EMF in hybrid excited machines with a switched flux stator is comprehensively investigated. In addition, a comparative study of the field back-EMF ripple in hybrid excited machines and wound field synchronous machines is conducted. It shows that the field back-EMF in flux-enhancing, zero field current, and flux-weakening modes is significantly affected by the hybridization ratio under different conditions. Moreover, the on-load field back-EMF in wound field machines is considerably higher than that in hybrid excited machines due to the mitigated magnetic saturation level in the field winding’s magnetic flux path. Finally, to validate the results predicted using the finite element method, a prototype hybrid excited machine is built and tested. Full article

Over the last nine decades, 2,2′:6′,2″-terpyridine (terpy) derivatives and their transition d-metal complexes have been extensively explored due to their unique and widely tuned optical, electrochemical, and biological properties. Terpyridyl transition metal complexes occupy a prominent position among functional molecular materials for applications in optoelectronics, life science, catalysis, and photocatalysis, as well as they have played a key role in determining structure–property relationships. This review summarizes the developments of amine-functionalized R-C₆H₄-terpy systems and their d-metal complexes, largely concentrating on their photophysical and electrochemical properties. Functionalization of the terpy core with the electron-rich group, attached to the central pyridine ring of the terpy backbone via the phenylene linker, gives rise to organic push–pull systems showing the photoinduced charge flow process from the peripheral donor substituent to the terpy acceptor. The introduction of amine-functionalized R-C₆H₄-terpy systems into the coordination sphere of a d-metal ion offers an additional way for controlling the photophysics of these systems, in agreement with the formation of the excited state of intraligand charge transfer (ILCT) nature. Within this review, a detailed discussion has been presented for R-C₆H₄-terpys modified with acyclic and cyclic amine groups and their Cr(III), Mn(I), Re(I), Fe(II), Ru(II), Os(II), Pt(II), and Zn(II) coordination compounds. Full article

Background: Spinal manual therapy (SMT) is widely used in the management of musculoskeletal pain. In addition to mechanical effects, SMT may induce neurophysiological changes at both central and autonomic levels. However, the extent and consistency of these short-term effects remain unclear. Objective: To systematically review the short-term effects of SMT on pain perception, central nervous system (CNS) activity, and autonomic nervous system (ANS) responses in adults with musculoskeletal pain or in healthy controls. Methods: A systematic review was conducted. Three databases (PubMed, ScienceDirect, Embase) were searched up to October 2023, with a final update in March 2025. Randomized controlled trials involving SMT and assessing outcomes related to pain, CNS, or ANS function were included. The methodological quality was assessed using the PEDro scale. The results were synthesized narratively and categorized by outcome domain. Four summary tables were created to present the study characteristics, main findings, methodological quality, and risk of bias. Results: Eleven trials were included. SMT produced variable effects on pain perception, with more consistent results observed when the treatment was applied frequently and followed standardized protocols. The CNS-related outcomes (e.g., fMRI connectivity, motor-evoked potentials) suggested short-term modulation of brain and spinal excitability in some studies. The ANS responses were heterogeneous, ranging from parasympathetic activation to sympathetic stimulation, depending on the intervention and population. The methodological quality was moderate to high in most studies, although the small sample sizes and limited blinding increased the risk of bias. The effect sizes were not consistently reported. Conclusions: SMT may induce short-term neuromodulatory effects on pain, CNS, and ANS activity. These effects appear to be context-dependent and require precise, repeated, and purposeful application. Full article

Bridges play a key and controlling role in transportation systems. Steel bridges are favored for their high strength, good seismic performance, and convenient construction. As important node connectors of steel bridges, high-strength bolts are extremely susceptible to damage such as corrosion and loosening. Therefore, accurate identification of bolt loosening is crucial. First, a new type of adhesive piezoelectric sensor is designed and prepared using PMN-PT piezoelectric single-crystal materials. The PMN-PT sensor and polyvinylidene fluoride (PVDF) sensor are subjected to steel plate fixed frequency load and swept frequency load tests to test the performance of the two sensors. Then, a steel plate component connected by high-strength bolts is designed. By applying exciter square wave load to the structure, the vibration response characteristics of the structure are analyzed to identify the loosening of the bolts. In addition, a piezoelectric smart washer sensor is designed to make up for the shortcomings of the adhesive piezoelectric sensor, and the effectiveness of the piezoelectric smart washer sensor is verified. Finally, a bolt loosening index is proposed to quantitatively evaluate the looseness of the bolt. The results show that the sensitivity of the PMN-PT sensor is 21 times that of the PVDF sensor. Compared with the peak stress change, the natural frequency change is used to identify the bolt loosening more effectively. Piezoelectric smart washer sensor and bolt loosening indicator can be used for bolt loosening identification. Full article

MXenes, a class of two-dimensional materials with appealing properties such as electrical conductivity, mechanical strength, and chemical stability, is rapidly gaining attention for potential applications in various fields, including energy storage, water treatment, biomedicine, and electromagnetic shielding. One of the most exciting developments is their integration with 3D printing technologies, which allows for precise control over material structure and composition. This combination has significantly expanded the scope of MXenes, particularly in electrochemical storage systems like supercapacitors and batteries, where 3D-printed MXene-based materials have demonstrated superior performance. This review article provides a detailed analysis of the synthesis, properties, and applications of MXenes, with a particular focus on their role in additive manufacturing. While the synergy between MXenes and 3D printing offers numerous advantages, challenges such as large-scale production, material stability, and refining processing techniques remain significant hurdles; all these issues are discussed in the present work. Future research directions are also highlighted that aim to enhance scalability, reduce costs, and explore new composite formulations to optimize the performance of MXenes across various applications. Full article

The study of vibration isolation devices has become an emerging area of research in view of the extensive damage to buildings caused by earthquakes. The ability to effectively isolate seismic vibrations and maintain the stability of a building is thus addressed in this paper, which evaluates the effect of horizontal ground excitation on the response of a structure isolated by a coupled isolation system consisting of a non-linear damper (QZS) and a friction pendulum system (FPS). A single-degree-of-freedom system was used to model structures whose bases are subjected to seismic excitation in order to assess the effectiveness of the QZS–FPS coupling in reducing the structural response. The results obtained revealed significant improvements in structural performance when the QZS–FPS system uses a damper of optimum stiffness. A 30% reduction in displacement was recorded compared with QZS alone for two signals, one harmonic and the other stochastic. The response of the QZS–FPS system with soft stiffness to a harmonic pulse reveals amplitudes reaching around eight times those of the pulse at low frequencies and approaching zero at high frequencies. In comparison, the rigid QZS–FPS coupling has amplitudes 0.9 and 3.5 times higher than those of the harmonic signal. Thus, the resonance amplitudes observed for the QZS–FPS system are lower than those reported in other studies. This analysis highlights the performance differences between the two types of stiffness in the face of harmonic pulses, underlining the importance of the choice of stiffness in vibration management applications. The stochastic results show that on both hard and soft soils, the new QZS–FPS system causes structures to vibrate horizontally with maximum amplitudes of the order of 0.003 m and 0.007 m respectively. So, QZS–FPS coupling can be more effective than all other isolators for horizontal ground excitation. In addition, the study demonstrated that the QZS–FPS combination can offer better control of building vibration in terms of horizontal displacements. Full article