Sensitive Applications Research Articles

Electroactive RuPt NPs programmed dual-channel electrochemical sensor for methyl mercaptan monitoring

The accurate and sensitive detection of methyl mercaptan (CH3SH) was of great significance for food corruption monitoring. Electroactive labels engineered electrochemical sensors possessed tailorable electrochemical responses, and showed potential prospects for CH3SH monitoring. In comparison to a single electrochemical signal, electroactive nanocomposites with multiple electrochemical responses not only provided multi-channel sensing signals for accurate detection, but also increased the peak intensity for sensitive detection. Herein, RuPt NPs were designed and explored to possess two independent and non-interfering electrochemical oxidation peaks at 0.75 V and -0.73 V. The formation of metal-SH covalent bonds between electroactive sites of RuPt NPs and CH3SH induced the changes of two electrochemical oxidation peaks. By utilizing the sum intensity of two electrochemical peaks as detection signal, a dual-channel electrochemical sensor was established for CH3SH detection in the range of 1 μM-1 mM, and had a low limit of detection (LOD) of 300 nM. This work gave a new insight into promoting more electroactive nanocomposites with multiple signals for accurate and sensitive electrochemical detection applications.

Synthesis, characterization, and application of novel fluorescent sporopollenin for effective detection of mercury (II) ions from aqueous media.

In this investigation, a novel environmentally friendly functionalized fluorescent Sp-TAB hybrid material was advanced for the sensitive detection of environmentally polluting Hg(II). The characterization of the synthesized fluorescent Sp-TAB hybrid material using SEM and EDX provided insights into morphological and structural changes in the material's pore structure, while XRD and FT-IR analyses revealed the impact of the prepared material at each stage. Optimal parameters such as temperature, contact time, and pH influencing Hg(II) ion detection were determined. Application of the fluorescent Sp-TAB hybrid material was determined a detection limit (LOD) of 4.87μM for Hg(II) ions. This study shows the potential of the immobilization-enhanced fluorescent Sp-TAB hybrid material for sensitive Hg(II) ion detection in tap water. Additionally, this study is believed to serve as a model for sensitive and practical detection applications of heavy metals in the future.

Continuous GPS PPP-AR frequency transfer links

Abstract In this paper, we show that the SPARK software of the Natural Resources Canada (NRCan) with their DCR (Decoupled Clock Rapid) products can be used to generate the PPP-AR continuous batch clock solutions of multiple days, which we use to build frequency transfer links between two remotely located GPS receivers. The reliability and confidence in forming the long-term frequency transfer links have been improved compared to reference~\cite{jian2023gps}. We compare the SPARK PPP-AR links to an optical fiber and TWSTFT links for hundreds of days. The ∽500-day-long comparisons with TWSTFT show no frequency bias for continental and cross-continental links. Frequency transfer links formed using the SPARK solutions have uncertainty of 1×10-15/T, where T is in days, without reaching the noise floor, a critical requirement for comparing optical frequency standards and for the redefinition of the SI second. The short latency of the NRCan DCR products enables the quick availability of the PPP-AR links presented in this paper marking it particularly relevant for time sensitive applications.

Experimental Study of Fiber-Optic Temperature Sensor Based on Dual FSIs

To improve the sensitivity measurement of temperature sensors, a fiber optic temperature sensor structure based on the harmonic Vernier effect with two parallel fiber Sagnac interferometers (FSIs) is designed, and theoretical analysis and experimental testing are conducted. The FSI consisting of two polarization maintaining fibers (PMFs) with lengths of 13.62 m and 15.05 m respectively is used to achieve the basic Vernier effect. Then by changing the length of one PMF to approximately i times that of the others, the FSI composed of two PMFs of 7.1 m and 15.05 m is used to achieve the first-order harmonic Vernier effect. Afterward, temperature sensing tests are conducted to observe the wavelength drift during temperature changes and ultimately achieve high sensitivity. The experimental results show that the temperature sensitivity of the sensor based on the first-order harmonic Vernier effect is −28.89 nm/°C, which is 17.09 times that of a single FSI structure (−1.69 nm/°C) and 1.84 times that of the sensitivity generated by the structure based on the basic Vernier effect (−15.69 nm/°C). The experimental results are consistent with the theoretical analysis. The structure proposed in this paper achieves drift measurement of 0.1 °C variation based on 1 °C drift, making the fiber optic temperature sensor applicable to related fields that require high precision temperature. The proposed temperature sensor has the simple structure, low production cost, high sensitivity, and broad application prospects.

Design, Calibration and Morphological Characterization of a Flexible Sensor with Adjustable Chemical Sensitivity and Possible Applications to Sports Medicine.

Active life monitoring via chemosensitive sensors could hold promise for enhancing athlete monitoring, training optimization, and performance in athletes. The present work investigates a resistive flex sensor (RFS) in the guise of a chemical sensor. Its carbon 'texture' has shown to be sensitive to CO2, O2, and RH changes; moreover, different bending conditions can modulate its sensitivity and selectivity for these gases and vapors. A three-step feasibility study is presented including: design and fabrication of the electronic read-out and control; calibration of the sensors to CO2, O2 and RH; and a morphological study of the material when interacting with the gas and vapor molecules. The 0.1 mm-1 curvature performs best among the tested configurations. It shows a linear response curve for each gas, the ranges of concentrations are adequate, and the sensitivity is good for all gases. The curvature can be modulated during data acquisition to tailor the sensitivity and selectivity for a specific gas. In particular, good results have been obtained with a curvature of 0.1 mm-1. For O2 in the range of 20-70%, the sensor has a sensitivity of 0.7 mV/%. For CO2 in the range of 4-80%, the sensitivity is 3.7 mV/%, and for RH the sensitivity is 33 mV/%. Additionally, a working principle, based on observation via scanning electron microscopy, has been proposed to explain the chemical sensing potential of this sensor. Bending seems to enlarge the cracks present in the RFS coverage; this change accounts for the altered selectivity depending on the sensor's curvature. Further studies are needed to confirm result's reliability and the correctness of the interpretation.

High-sensitivity miniaturized spectrometers using photonic crystal slab filters.

Miniaturized spectrometers have emerged as pivotal tools in numerous scientific and industrial applications, offering advantages such as portability, cost-effectiveness, and the capability for onsite analysis. Despite these significant benefits, miniaturized spectrometers face critical challenges, particularly in sensitivity. Reduced dimensions often lead to compromises in optical path length and component quality, which can diminish detection limits and limit their applications in areas such as low-light-level measurements. Here we developed a compact spectrometer that integrates an array of photonic crystal slab filters with band-stop spectral transmission characteristics into an image sensor. Compared to traditional gratings or bandpass filter strategies, where each detector can only read light of a single wavelength component, our band-stop strategy allows each detector to read the light of all wavelengths except the band-stop wavelength. This maximizes energy extraction from incident signals, significantly improving the sensitivity of the spectrometer. Spectral reconstruction is achieved mathematically using pre-calibrated band-stop responses combined with a single coded image. Our spectrometer delivers a spectral resolution of 1.9 nm and demonstrates sensitivity more than ten times greater than that of conventional grating spectrometers during fluorescence spectroscopy of Ascaris lumbricoides. The design is fully compatible with complementary metal-oxide-semiconductor (CMOS) technology, allowing for mass production at low costs and thus promising broad deployment in sensitive applications.

Enhancing user experience and trust in advanced LLM-based conversational agents

This study explores the enhancement of user experience (UX) and trust in advanced Large Language Model (LLM)-based conversational agents such as ChatGPT. The research involves a controlled experiment comparing participants using an LLM interface with those using a traditional messaging app with a human consultant. The results indicate that LLM-based agents offer higher satisfaction and lower cognitive load, demonstrating the potential for LLMs to revolutionize various applications from customer service to healthcare consultancy and shopping assistance. Despite these positive findings, the study also highlights significant concerns regarding transparency and data security. Participants expressed a need for clearer understanding of how LLMs process information and make decisions. The perceived opacity of these processes can hinder user trust, especially in sensitive applications such as healthcare. Additionally, robust data protection measures are crucial to ensure user privacy and foster trust in these systems. To address these issues, future research and development should focus on enhancing the transparency of LLM operations and strengthening data security protocols. Providing users with clear explanations of how their data is used and how decisions are made can build greater trust. Moreover, specialized applications may require tailored solutions to meet specific user expectations and regulatory requirements. In conclusion, while LLM-based conversational agents have demonstrated substantial advantages in improving user experience, addressing transparency and security concerns is essential for their broader acceptance and effective deployment. By focusing on these areas, developers can create more trustworthy and user-friendly AI systems, paving the way for their integration into diverse fields and everyday use.

Fabrication of Nanobioengineered Interfaces Utilizing Quaternary Nanocomposite for Highly Efficient and Selective Electrochemical Biosensing of Urea.

Nanobioengineered interfaces have gained attention owing to their small size and high surface area-to-volume ratio for utilization as a platform for highly selective and sensitive biosensing applications owing to the integration of biological molecules with engineered nanomaterials/nanocomposites. In this work, a novel Ag-complex, [(PPh3)2Ag(SCOf)]-based quaternary Ag-S-Zn-O nanocomposites (NCs), was synthesized through an environmentally-friendly process. The results revealed the formation of the NCs with an average crystallite size and particle size of 36.08 and 40.22 nm, respectively. In addition, this is the first study to utilize such NCs synthesized via a single-source precursor method, offering enhanced sensor performance due to their unique structural properties. Further, these NCs were used to fabricate a urease (Ur)/Ag-S-Zn-O NCs/ITO nanobioengineered electrode for precise and sensitive electrochemical biosensing of urea. The interfacial kinetic studies revealed quasi-reversible processes with high electron transfer rates and linear current responses, indicating efficient reaction dynamics. A high diffusion coefficient and low surface concentration suggested a fast diffusion-controlled process, affirming the electrode's potential for rapid and sensitive urea detection. The biosensor demonstrated notable sensing properties such as high sensitivity (12.56 μA mM-1 cm-2) and a low detection limit (0.54 mM). The fabricated bioelectrode was highly selective and reproducible and demonstrated stability for up to 60 days. These results validate the potential of this nanobioengineered interface for next-generation biosensing applications, paving the way for advanced point-of-care diagnostics and real-time health monitoring.

Solid-state Ru(bpy)32+ electrochemiluminescence sensor for trace detection of fenpropathrin using loofah sponge-like carbon nanofibers and CdS.

Loofah sponge-like carbon nanofibers (LF-Co,N/CNFs) were utilized as a carrier for Ru(bpy)32+, and then combined with CdS to create a novel solid-state electrochemiluminescence sensor capable of detecting trace amounts of fenpropathrin. LF-Co,N/CNFs, obtained through the high-temperature pyrolysis of ZIF-67 coaxial electrospinning fibers, were characterized by a loofah-like morphology and exhibited a significant specific surface area and porosity. Apart from serving as a carrier, LF-Co,N/CNFs also functioned as a luminescence accelerator, enhancing the system's luminescence efficiency by facilitating electron transmission and reducing the transmission distance. The inclusion of CdS in the luminescence reaction, in conjunction with Ru(bpy)32+, further boosted the sensor's luminescence signal. The resulting sensor demonstrated a satisfactory signal, with fenpropathrin causing significant quenching of the ECL signal.Under optimized conditions, a linear relationship between the signal quench value and fenpropathrin concentration in the range 1 × 10-12 to 1 × 10-6M was observed, with a detection limit of 3.3 × 10-13M (S/N = 3). This developed sensor ischaracterized by its simplicity, sensitivity, and successful application in detecting fenpropathrin in real samples. The study not only presentsa straightforward detection platform for fenpropathrin but also introduces new avenues for the rapid determinationof various food contaminants, thereby expanding the utility of carbon fibers in electrochemiluminescence sensors.

Effect of blue light emitting diode therapy on recurrent vulvovaginal candidiasis: A randomized assessor-blinded controlled trial.

Vulvovaginal Candidiasis (VVC) is a prevalent genital infection in women of reproductive age and requires effective non-drug therapies. Therefore, this study aimed to investigate the effect of blue light emitting diode (LED) therapy as an alternative treatment for recurrent VVC due to its proven antimicrobial properties. The safety and non-invasiveness of LED therapy make it a promising option for sensitive tissue applications. This randomized controlled trial recruited 60 women with culture-confirmed VVC. Participants were randomly allocated to two groups. Group A (control group) received standard antifungal treatment with Gynoconazol 0.8% vaginal cream for three consecutive nights (n=30). Group B (study group) received the same antifungal treatment plus two 60-min sessions of blue LED therapy directed at the vagina and vulva, with the sessions separated by two days (n=30). Candida count (via CHROMagar™ Candida) and vaginal pH (via AD110-AD111m) were assessed at baseline and one week after initiating treatment. Post-treatment, group (B) demonstrated a significantly greater reduction in Candida count compared to group (A) (mean difference (MD) 8.267; 95% Confidence Interval (CI) 6.723-9.811; p=0.0001). However, there was no statistically significant difference in vaginal pH between the groups (MD -0.03; 95% CI -0.244-0.178; p=0.749). Blue LED therapy effectively reduces Candida count in women with recurrent VVC without adversely affecting the vaginal pH, highlighting its safety and efficacy as a treatment modality.

Robust secret color image sharing anti-cropping and tampering in shares

Secret image sharing (SIS) has excellent properties such as loss tolerance and relatively low computational complexity, providing a brand-new solution for image security protection. However, there has been little research on the robustness of SIS systems, such as how to resist cropping or malicious tampering in shares. Existing related schemes generally focus on grayscale images and suffer from issues such as lossy recovery, weak robustness, and serious pixel expansion, which are challenging to meet the requirements of high-quality sensitive image applications. In this regard, a robust SIS scheme for color images is proposed, which can resist large-scale cropping and malicious tampering in shares. According to the idea of “breaking up the whole cropped area into parts, repairing the shares independently”, the proposed scheme can realize lossless recovery of secret images through organic fusion of secret sharing, error-correcting code, and pixel re-arrangement techniques. Even if all the shares are cropped by 25%, it can still achieve lossless recovery regardless of whether the cropping positions intersect or overlap. It can also resist various malicious tampering (such as marking, defacing, and copy-move forgery) as well as image noise. Moreover, it avoids pixel expansion and requires no auxiliary encryption or preprocessing. Theoretical analysis and experimental results demonstrate that the proposed scheme is superior to existing schemes in terms of robustness and comprehensive performance, and is expected to promote the practical application of SIS.

Mental Health Effects of COVID-19 Among Health Care Providers: A Case Study of Kalulushi General Hospital in Kalulushi District, Zambia

Coronavirus disease 2019 is an infectious disease which was first identified in Wuhan a City in the Peoples Republic of China in December 2019. The aim of this study was to establish the mental health effects of COVID 19 on the frontline health care providers at Kalulushi General Hospital in Kalulushi district of Zambia. A descriptive cross-sectional study was employed to assess the mental health effects of COVID 19 on the frontline health care providers at Kalulushi General Hospital in Zambia. The study used simple random sampling technique to select 122 respondents to participate in the study. Data was collected from study participants using structured questionnaire. The collected data was analyzed using SPSS version 25 and MS excel and was presented using tables, bar charts and pie charts. Multivariate logistic regression analysis was used to examine the relationships between socio-demographic characteristics and mental health effects of COVID-19 parameters. The ethical approval was gotten from Lusaka Apex Medical University Biomedical Research Ethics Committee, Kalulushi General Hospital and Kalulushi District Health Office respectively. The study revealed that, most of the respondents (31%) were afraid of contracting COVID-19, while 27% of study participants claimed that COVID 19 was a propaganda and that no one knew when it would end. The study also found that, a small proportion of study participants reported a decline in work morale (17%), likely associated with witnessing numerous deaths (19%) and the added stress of inadequate personal protective equipment (PPE) experienced by 15%. The study further demonstrated that 58% of the respondents accepted that working in a COVID-19 environment affected their mental health while 42% of the respondents did not accept that working in the COVID-19 environment did affect mental health of frontline healthcare providers. The study further revealed that, most of the respondents were using handwashing or sanitizers, facemasks and protective clothing (27%) to cope with COVID-19 pandemic. The study also showed that, a few respondents were practicing social distancing (22%), and having healthy diet (19%) in order to cope with COVID-19. Marital status and religion were found to have significant association with copying strategies of frontline healthcare providers against COVID-19 pandemic at Kalulushi General Hospital in Kalulushi District of Zambia (P < 0.05). WHO, CDC, and Zambian Ministry of Health should prioritize implementing Critical Incident Stress Management protocols, develop culturally sensitive mobile applications to offer self-guided interventions, and promote healthy coping mechanisms among frontline healthcare providers.

The Electromagnetic Noise Level Influence on the Laser Micro-Perforation Process Specific to Automotive Components.

This article focuses on the influence of generated electromagnetic noise (energy) during the micro-perforation process. This study aims to investigate the critical parameters and effects of using laser technology in the processing of textile materials for airbags. Different levels of electromagnetic noise and material thicknesses were investigated to ensure the quality of manufactured parts and the best component performance. A factorial analysis (DOE) was developed to evaluate the influence of electromagnetic noise levels over pull test results and its effect on the micro-perforation process. The overall inferential analysis concludes a significant influence of the noise levels on micro-perforation processing. The detailed analysis suggests that 1.2 V is an optimal level of electromagnetic noise where the material maintains its mechanical properties in a more predictable and consistent manner. Additionally, the factorial design provides significant evidence for an interaction and main effects' influences of analyzed factors. The obtained results in this study have demonstrated that monitoring and controlling the noise level have beneficial effects over the laser processing. This ensures that the safety aspect of the produced parts is entirely upheld and protected. Also, this research contributes to improving the manufacturing process and ensures that high-quality products are obtained, being suitable for use in sensitive applications such as automotive airbags.

An Efficient Image Encryption Scheme for Medical Image Security

In the contemporary landscape of digital healthcare, the confidentiality and integrity of medical images have become paramount concerns, necessitating the development of robust security measures. This research endeavors to address these concerns by proposing an innovative image encryption scheme tailored specifically for enhancing medical image security. The proposed scheme integrates a sophisticated blend of symmetric and asymmetric encryption techniques, complemented by a novel key management system, to fortify the protection of medical image data against unauthorized access and malicious tampering. The proposed DNA-based encryption algorithm leverages the unique properties of DNA encoding to securely scramble image data, providing an added layer of protection. By utilizing DNA sequences in the encryption and decryption processes, the scheme achieves a high level of data confusion and diffusion, significantly enhancing security. The efficacy of the proposed encryption scheme is validated through comprehensive experimental evaluations, which demonstrate its proficiency in ensuring data security while maintaining computational efficiency. The scheme's compatibility with existing medical imaging systems is also examined, affirming its seamless integration into contemporary healthcare infrastructures. This research contributes to the advancement of medical image security by proposing an efficient encryption scheme that strikes a balance between stringent security requirements and practical implementation considerations. The primary contributions include the development of a DNA-based encryption algorithm and a novel key management system, both of which significantly enhance the security of medical images. This research contributes to the advancement of medical image security by proposing an efficient encryption scheme that strikes a balance between stringent security requirements and practical implementation considerations. By safeguarding the confidentiality and integrity of medical images, the proposed scheme empowers healthcare providers to uphold patient privacy and trust in the digital age. Experimental results show that this approach ensures robust encryption without compromising image quality, making it suitable for sensitive medical imaging applications.

Effect of voltage amplitude and frequency on the characteristic parameters of a piezoelectric actuated micro-blower

Micro-blower is an innovative device that is used for sensitive applications such as electronics cooling, avionics and the medical field. It features a piezoelectric disc (PED)-diaphragm assembly. A 3D computational model of micro-blower is developed and simulated using COMSOL Multiphysics and studied its characteristic parameters such as maximum displacement (w), average velocity (w̅’), maximum von Mises stress (Tv), total kinetic energy (EK), total elastic strain energy (EU) and total electric energy (EE). The frequency-dependent electric potential difference was supplied to the Lead Zirconate Titanate (PZT-5H) PED. Seven different square wave ultrasonic frequencies were used as input for the PED ranging from 22 to 28 kHz, a resonance frequency is proposed in the study. There were three peak-to-peak voltages, Vp-p, of 10, 15 and 20 V were used. The characteristic parameters were estimated for the diaphragm, PED and PED-diaphragm assembly. For a 20 Vp-p and at 27 kHz, the maximum w reached 1.987 µm. The maximum Tv on the diaphragm surface and EE developed in the PED were 29.925 MPa and 442.98 nJ, respectively. The present numerical results were validated with previous studies on a similar domain and were in good agreement.

THP as a sensor for the electrochemical detection of H2O2

Hydrogen peroxide (H2O2) detection is paramount in biological and clinical domains due to its pivotal role in various physiological and pathological processes. This molecule is a crucial metabolite and effector in cellular redox mechanisms, influencing diverse cellular signaling pathways and bolstering the body’s defense mechanisms against infection and oxidative stress. Organic molecule-based electrodes present unique advantages such as operational versatility and scalability, rendering them attractive candidates for sensor development across diverse fields encompassing food safety, healthcare, and environmental monitoring. This study explores the electrochemical properties of a tris(3-hydroxypyridin-4-one) THP, which has been unexplored in electrochemical sensing. Leveraging THP’s chelating properties, we aimed to develop an electrochemical probe for hydrogen peroxide detection. Our investigations reveal promising results, with the developed sensor exhibiting a low limit of detection (LOD) of 144 nM, underscoring its potential utility in sensitive and selective H2O2 detection applications. In addition, the new sensor was also tested on fetal bovine serum (FBS) to emphasize future applications on biological matrices. This research signifies a significant stride in advancing electrochemical sensor technologies for hydrogen peroxide detection with several novelties related to the usage of THP, such as high sensitivity and selectivity, performance in biological matrices, repeatability, stability, and reproducibility, economical and practical advantages. This research opens new avenues for enhanced biomedical diagnostics and therapeutic interventions.

A new mechanical engineering strategy based on microsphere probe and its application in transition metal dichalcogenides

Mechanical engineering of 2D materials allows continuous and reversible modulation of their electronic and photonic properties. Although photoluminescence (PL) measurement is an effective way to monitor the effects of mechanical forces on 2D semiconductors, there is currently a lack of techniques to enhance PL signals during stress application. This study presents an innovative mechanical engineering approach that integrates a dielectric microsphere as an atomic force microscopy (AFM) probe into a Raman-AFM system. Force–distance curve tests and COMSOL simulations were performed to analyze and estimate the compressive stress exerted by the microsphere. Importantly, the PL signals of transition metal dichalcogenides subjected to microsphere probe's force were enhanced and reveal distinct mechanical responses depending on the substrate rigidity: compressive pressures for rigid substrates and tensile strains for flexible ones. Notably, this strategy not only amplifies spectral signals in real time but also achieves fine stress modulation in the precise targeted material region, demonstrating its superiority in sensitive mechanical engineering applications. Our work offers a new avenue for the deliberate design of mechanical strains in 2D materials, which is crucial for optimizing the performance of related devices.

Micro-macro SERS strategy for highly sensitive paper cartridge with trace-level molecular detection

Surface-enhanced Raman Scattering (SERS) has become a powerful spectroscopic technology for highly sensitive detection. However, SERS is still limited in the lab because it either requires complicated preparation or is limited to specific compounds, causing poor applicability for practical applications. Herein, a micro-macro SERS strategy, synergizing polymer-assisted printed process with paper-tip enrichment process, is proposed to fabricate highly sensitive paper cartridges for sensitive practical applications. The polymer-assisted printed process finely aggregates nanoparticles with a discrete degree of 1.77, and SERS results are matched with theoretical enhancement, indicating small cluster-dominated hotspots at the micro-scale and thus 41-fold SERS increase compared to other aggregation methods. The paper-tip enrichment process moves molecules in a fluid into small tips filled with plasmonic clusters, and molecular localization at hotspots is achieved by the simulation and optimization of fluidic velocity at the macro-scale, generating a 39.5-fold SERS sensibility increase in comparison with other flow methods. A highly sensitive paper cartridge contains a paper-tip and a 3D-printed cartridge, which is simple, easy-to-operate, and costs around 2 US dollars. With a detection limit of 10 −12 M for probe molecules, the application of real samples and multiple analytes achieves single-molecule level sensitivity and reliable repeatability with a 30-min standardized procedure. The micro-macro SERS strategy demonstrates its potential in practical applications that require point-of-care detection.

High‐performance shape memory characteristics by integrating urea linkages into the polyurethane elastomer

AbstractShape memory polymers have been widely researched to develop multifunctional materials that respond smartly to external stimulations and programmed signals. Among them, shape memory polyurethane (SMPU) is drawing great attention owing to its highly tunable properties and ease of integrating new functions. However, the effect of urea bonds on SMPU elastomers has rarely been investigated because of the extreme reactivity of amine crosslinkers. In this study, we used diethanolamine (DEOA), which contains a secondary amine, as the crosslinker for SMPU synthesis. Unlike other crosslinkers containing primary amines, they can form urea bonds in a more gentle manner. The urea bonds reinforce the intermolecular interactions between the hard segments with strong hydrogen bonding, thus increasing the phase separation and degree of crystallization. Consequently, the urea‐containing SMPU exhibits improved mechanical strength and shape memory abilities for both fixing and recovery. Moreover, the transcarbamoylation reaction, which enables the reconfiguration of the original shape, is observed. The introduction of the urea bonds into the SMPU elastomer can be beneficial in achieving flawless shape memory performances in various sensitive applications.

Enhancing mixing efficiency of a circular electroosmotic micromixer with cross-reciprocal electrodes

Enhancing mixing efficiency in microscale processes for sensitive biomedical, pharmaceutical, and chemical applications is crucial, particularly when operating under low-velocity constraints. This study presents a comprehensive investigation into the impact of various factors on microfluidic mixing within a circular mixing chamber micromixer, utilizing electroosmotic principles. The governing equations are solved numerically using the finite element technique-based solver. This research examines the effects of microchamber diameter (D), inlet velocity (uo), alternating current (AC) voltage amplitude (ϕo), and AC frequency (f) on fluid mixing dynamics. Several key findings are noted from this study. The reduction of the circular microchamber diameter decreases the linear distance between cross-reciprocally placed microelectrodes, resulting in increased electroosmosis force and mixing efficiency. The voltage amplitude within the specified range shows increased mixing efficiency when fluid species are combined at appropriate velocity and AC frequency. The highest mixing efficiency of 98.84% is achieved with the following parameters: flow velocity (uo) of 150 μm/s, AC frequency of 4 Hz, voltage amplitude of 500 mV, and microchamber diameter of 20 μm. At a frequency of 12 Hz and voltage amplitude of 500 mV, the mixing efficiency exceeds 94.66% across a wide range of input velocities (100–200 μm/s), enabling versatile control in microfluidic devices. The nonlinear interaction between electroosmotic flow and microchamber geometry significantly contributes to this enhanced mixing efficiency. These results demonstrate the potential for optimizing microfluidic mixing processes through careful parameter tuning, particularly in applications requiring high efficiency at low flow rates. Thus, this study provides valuable insights for designing more effective microfluidic systems in various scientific and industrial fields.