Wide Working Range Research Articles

Highly sensitive piezoresistive and thermally responsive fibrous networks from the in situ growth of PEDOT on MWCNT-decorated electrospun PU fibers for pressure and temperature sensing

Flexible electronics have demonstrated various strategies to enhance the sensory ability for tactile perception and wearable physiological monitoring. Fibrous microstructures have attracted much interest because of their excellent mechanical properties and fabricability. Herein, a structurally robust fibrous mat was first fabricated by electrospinning, followed by a sequential process of functionalization utilizing ultrasonication treatment and in situ polymerization growth. Electrospun polyurethane (PU) microfibers were anchored with multi-walled carbon nanotubes (MWCNTs) to form conductive paths along each fiber by a scalable ultrasonic cavitation treatment in an MWCNT suspension. After, a layer of poly(3,4-ethylene dioxythiophene) (PEDOT) was grown on the surface of PU fibers decorated with MWCNTs to enhance the conductive conjunctions of MWCNTs. Due to the superior electromechanical behaviors and mechanical reinforcement of PEDOT, the PEDOT/MWCNT@PU mat-based device exhibits a wide working range (0–70 kPa), high sensitivity (1.6 kPa−1), and good mechanical robustness (over 18,000 cycles). The PEDOT/MWCNT@PU mat-based sensor also demonstrates a good linear response to different temperature variations because of the thermoelectricity of the PEDOT/MWCNT composite. This novel strategy for the fabrication of multifunctional fibrous mats provides a promising opportunity for future applications for high-performance wearable devices.

Ti3C2T x quantum dots/leaf veins based sensors with ultra-broadrange high sensitivity

Flexible pressure sensors and electronic skins have attracted more and more attention in human–machine interaction, intelligent robotics, and wearable health monitoring electronics. However, it is still challenging to trade off between high sensitivity and a wide working range to meet a variety of pressure applications. Herein, we reported a flexible pressure sensor assembled by a simple and cost-effective approach using coating Ti3C2T x quantum dots on leaf veins. Due to the ultrahigh specific surface area, excellent electrical conductivity, and hierarchical micro-network structure, the device shows excellent sensitivity (25.83 kPa−1), a wide working range (0.1–1500 kPa), remarkable high-pressure resolution (5 kPa under high pressure of 100 kPa or 5%), high stability (over 4000 cycles) and fast response time (<0.3 s). Furthermore, we demonstrated the applications of body motion monitoring during different parts and activities. The results prove our device is a potential candidate for next-generation wearable electronics and human–machine interaction.

A systematic literature review of university-industry partnerships in engineering education

ABSTRACT Over the last few decades, a wide range of works have featured studies documenting successful pedagogic collaborations in the form of university-industry partnerships in engineering education. In light of this, we conducted a systematic literature review of these studies centred around five key research questions: (a) purposes of university-industry collaborations, (b) theories used to guide such work, (c) types of methods employed, (d) evidence-based best practices identified and (e) areas of future work to be explored. Publications were selected for inclusion by screening and appraising results obtained from databases and keywords refined through a scoping study. We conclude from our findings that future studies would benefit from better alignment with literature or theoretical frameworks and specific robust methods. Additionally, early and middle years of undergraduate engineering programs offer underutilised opportunities for partnership, in line with designing a more futures-focused educational curriculum.

The Role of Language in Shaping Identity in Indian Literature: A Critical Study

In India’s cultural tapestry, which is diverse and multifaceted with a strong literary tradition, language and identity are intertwined. The deep connection between language and identity in Indian literature is explored in this critical study, which provides insights into how language functions as a potent tool in the creation, preservation, and alteration of both individual and collective identities in the Indian setting. This study investigates the crucial function of language in forming, developing, and reflecting the identities of the people of India, drawing on a wide range of Indian literary works. Undoubtedly, one of the most challenging procedures in life is learning a language other than one’s native tongue. It is a startlingly drawn-out experience that is reliant on mental, emotional, and physical factors. The second language learners should alternate between thinking of themselves as first-language speakers and second-language learners, which forces them to consider how they “identify” themselves. Teachers no longer just play a supporting role in the global education system. The idea of identity is one of the most recent topics that is being researched widely across the world.

From network to channel: Crack-based strain sensors with high sensitivity, stretchability, and linearity via strain engineering

High-performance stretchable strain sensors are highly desirable for various scenarios, such as health monitoring and human-robot interfaces. Here, we propose a universal strain engineering strategy that introduces an inhomogeneous spatial distribution of stress and promotes crack propagation behavior leading to a critical state between network and channel morphologies, achieving stretchable strain sensors with high sensitivity, a wide working range and good linearity. Approaches for introducing soft-rigid interfaces, enlarging elastic modulus mismatches and matching dimensions have been employed to execute the strategy for network-crack strain sensors with collapsed nanocone cluster structures as representatives. The strain sensors can be tuned to realize a gauge factor of 690.95 in a linear working range of 0–40% (R2 = 0.993) or a gauge factor of 113.70 in a larger linear working range of 0–120% (R2 = 0.999). Intraocular pressure monitoring and dynamic facial asymmetry assessment have been demonstrated based on these sensors to show their great application potential.

Development and validation of a method based on liquid chromatography-mass spectrometry for comprehensive profiling of phenolic compounds in rice

The consumption of rice grains containing phytochemicals associated with antioxidant activity can potentially reduce the risk of chronic diseases. These phytochemicals, which include phenolic acids, anthoxanthins, and anthocyanins, are present in both free and bound forms in rice grains. However, there is limited documentation on the development of a method for determining the simultaneous amount of both free and bound phenolic compounds using sensitive analytical techniques. To address this gap, a study was conducted to develop and validate a liquid chromatography-mass spectrometric detection method for quantifying eighteen phenolic compounds in rice grains, both in free and bound forms. Paracetamol was used as the internal standard to minimize the effect of matrix interferences. The method was validated by measuring its working range, linearity, accuracy, precision, limits for detection and quantification, robustness, and expanded uncertainty. The method has a wide working range of 1.0 to 30.0 mg/kg for each phenolic compound and good linearity, with regression coefficients of calibration graphs greater than 0.999. Accuracy was determined using the recoveries after fortification at three concentration levels, which were in the range of 83.1 to 101.2%. Precision was expressed as a percentage of relative standard deviation (%RSD), which was below 7.62% for all determined phenolic compounds. The detection limits (LoD) and quantification limits (LoQ) ranged between 0.53 and 0.75 mg/kg and 0.54–0.77 mg/kg, respectively. The percentages of expanded uncertainties at the coverage factor of 2 (k = 2) were below 11.7%. The method was also evaluated for its robustness by obtaining recoveries at satisfactory levels for three different kinds of cereal; wheat, maize, and millet. The validated method is an accurate and reproducible approach for the simultaneous determination of phenolic compounds present at low levels in a complex matrix such as rice. The study also found that the phenolic profiles vary among rice genotypes, which can significantly impact human health by varying the nutraceutical properties of rice grains as health-promoting aspects.

Flexible pressure sensor enhanced by polydimethylsiloxane and microstructured conductive networks with positive resistance-pressure response and wide working range

Improving the performance of flexible pressure sensors has received increasing attention owing to their numerous applications in advanced technologies. However, many approaches that yield exceptional performance often involve complex manufacturing processes and high costs, which are not conducive to the large-scale production and application of flexible pressure sensors. Therefore, this paper presents a simple and efficient method, combining a pre-strain strategy with polydimethylsiloxane infiltration, for manufacturing flexible pressure sensors with a wide working range, enhanced sensitivity, and good stability. Sensors fabricated using this method exhibit an improved sensitivity of 0.0331 kPa−1 within the broad working range of 0.11–1250 kPa, ultra-fast response time of 8 ms, and good stability as well as repeatability over 2500 cycles of 15% strain loading. The sensing mechanism and resistance model of the sensor were investigated, and a sensing model based on the tunneling effect and resistance model was developed. The coefficient of determination between the model and the experimental data exceeded 0.99, thereby verifying its validity. Finally, a sensor array was tested to locate the pressure and recognize the object shape within a large pressure range, demonstrating its potential applications in engineering fields with high-pressure requirements. This study provides a reference for the simple and cost-effective manufacturing of advanced flexible sensors and offers valuable insights into the large-scale production of flexible sensors.

Pressure-temperature dual-parameter sensors designed by wood-derived thermoelectric composites: Micro-pressure high sensitivity

Fabricating flexible pressure-temperature dual-parameter sensors with micro-pressure high-sensitivity by selecting sensing materials and designing structures remains a great challenge. Herein, an arch-shaped lamellar porous (ASLP) wood sponge (WS) with a rough surface was prepared from natural wood (NW). The thermoelectric composites as the sole sensing materials were prepared by WS skeleton. A flexible dual-parameter sensor with real-time detection was treated by dimethyl sulfoxide (DMSO) vapor, and this sensor could differentiate the pressure and temperature stimuli. The mutual interference between the pressure and temperature signals of the sensor could be ignored. The stimuli sensitivity and discriminability of the sensor were improved by the rough surface and ASLP structure, which exhibited an excellent micro-pressure sensitivity of about 67.2 kPa−1. In addition, the sensor had a wide working range, fast response and long-term stability. The overall excellent sensing properties of the flexible dual-parameter sensor were demonstrated by detecting radial artery pulse and pressure-temperature complex signal of human motion. The flexible dual-parameter sensor prepared by this research can provide potential applications in healthcare devices and artificial intelligence.

A ratiometric fluorescent probe based on cyclization mechanism to identify hydrazine in environment and living cells

A colorimetric and ratiometric fluorescent probe containing hydroxyl-chalcone moiety as sensing site has been investigated to monitor hydrazine in actual water/soils, gas environment, and living cells. After adding hydrazine, the chalcone structure was cyclized and dihydropyrazole ring was formed, realizing the obvious fluorescence change from red (590 nm) to blue (480 nm) with 110 nm fluorescence peak shift. The probe has low detection limit (0.45 µM), large upgraded ratiometric fluorescence change (I480/I590, 66-fold), and wide pH work range (3.0-10.0). Probe CCA also can monitor hydrazine from actual water/soil samples, liquid/vapor hydrazine with portability and living cells.

A highly sensitive flexible pressure sensor based on laser-induced graphene and a composite dielectric structure

Pressure sensors are widely used in aerospace, mechanics, and medical electronics. Among them, capacitive pressure sensors with diversified electrode materials and dielectric microstructures have been extensively investigated for better performance. However, current prevailing construction strategies for pressure sensors mainly involve expensive metal electrodes and the complicated fabrication process for the microstructured dielectric layer. Here, we propose a flexible capacitive pressure sensor based on laser-induced graphene (LIG) and a composite dielectric structure with a quick and straightforward fabrication method. Due to the multiple deformation properties of porous graphene and air chambers, the sensor exhibits a wide working range between 0 Pa to 10.4 kPa, high sensitivity up to 2.52 kPa-1, and a detection limit as low as 1.2 Pa. The simple but precise fabrication approach offers a reliable structure for the sensor, thereby resulting in a rapid response and excellent cycling stability. On the basis of the outstanding comprehensive performance, our pressure sensors display great potential in practical applications such as health monitoring and motion detection.

Flexible and strain conductive cotton yarn enabled by low-temperature sintering of silver paste with multifunctional sensing capability in human motion detection and wearable applications

Flexible wearable textiles have attracted increasing attention, due to their potential applications in human motion detection, electric heating and humidity monitoring. However, the rigidity of metal materials contradicts the flexibility of textiles, and the complex preparation process and unfriendly environment hinder the development of metal materials as conductive materials of smart textiles. This study proposed a simple and environmentally friendly solution for smart textile preparation. Drawing on the bionic design principle of long-horned beetle’s exocuticle, the conductive layer on the surface of cotton yarn (CY) was formed by sintering the silver paste under low temperature of 200 ˚C. Silver Paste (SP) mainly composed with silver particles, terpineol (TE) and ethyl cellulose (EC). The resultant conductive yarn was characterized with high flexibility and high conductivity (4.08 × 103 S/cm). The conductivity of the yarn increases under tensile force, while decreases under non-tensile bending action. The strain sensor prepared by the yarn has a wide working range and high sensitivity, with distinguish performances of signal output according to the motion of different human body parts. The sensing behavior was also highlighted with the capability of micro-vibration strain of the human body, such as response to the pulse and throat. Furthermore, the conductive property of sintered silver paste cotton yarn (SSP-CY) has the capability of electric heating. The electric heating device based on SSP-CY can realize wired and radio heating, which resulted a maximum temperature of about 41 ℃. Therefore, the novel conductive cotton yarn has great potential in the application of high-sensitive wearable electronic devices.

Melody Master Tchaikovsky: Analysis of Ethnic Colors in the Piano Suite "Four Seasons"

Tchaikovsky was a great musician in Russia during the Romantic period. Due to his melodic works, he was known as the "master of melody" in Russia and received an honorary doctoral degree from the University of Cambridge in the United Kingdom. His creative genres cover a wide range of opera, dance, symphonies, concertos, and piano works. His music incorporates the characteristics of folk songs and his works reflect the oppressive psychology of the Russian people under the Tsar's rule, as well as their longing and longing for a better life in the future. He is committed to revealing the conflicting emotions within people's hearts. His later works are full of strong dramatic conflicts, his own thoughts on life, and fiery emotional colors. This article takes Tchaikovsky's piano suite "Four Seasons" as the text, and analyzes the ethnic characteristics of Tchaikovsky's works from the perspective of ethnology, using acoustic methods. The aim is to clarify the ethnic colors in "The Four Seasons" and reveal the profound ethnic connotations in Tchaikovsky's music works by utilizing elements such as harmony and melody.

A linear and large-range pressure sensor based on hierarchical structural SnO2@carbon nanotubes/polyurethane sponge

Flexible pressure sensors arouse an extensive interest in health monitoring, human-computer interaction, and wearable electronic devices. However, the preparation of pressure sensors with high sensitivity, high linearity, and wide working range continues to be challenging. In this study, a SnO2@carbon nanotubes/polyurethane (SnO2@CNT/PU) sponge pressure sensor was presented with high sensitivity in a wide linear pressure range. SnO2 was attached to CNT/PU sponge, which allowed the pressure sensor to obtain low initial current, thus increasing the sensitivity of the pressure sensor. The applied compressive strain was linearly related to the resistance since the nodes of CNT/PU sponge porous skeleton change synchronously during contact. SnO2@CNT/PU sponge pressure sensor shows a wide pressure range (3 Pa–30 kPa), while maintaining high sensitivity (53.4 kPa−1), and excellent linearity (R2 = 0.996). Furthermore, the sensor exhibited stable cycle performance (1500 cycles), fast response time (23 ms), as well as low detection limit (3 Pa). More importantly, the pressure sensor is capable of accurately detecting the human body's physiological signals, and shows promising application for health monitoring.

The Choice of Rational Parameters in Designing the Impact Mechanism

This paper presents the process of a hydraulic hammer designing. The terms of reference for hummer is corresponded to the requirements for conducting a wide range of works related to the crushing of rocks for producing hydraulic and road tunnels, for trenching works on rocky soils and others. For this purpose, simulation models of programs «Research» and «Zolotnik», which provide the solution of two sequentially performed tasks in the design and operational settings.

Design of MWCNTs and rGO co‐decorated elastic core‐spun yarn towards multifunctional flexible strain sensor with low detection limit and wide working range

AbstractIn order to reduce the detection limit and improve the working range of flexible strain sensor, in this article, we reported a multi‐walled carbon nanotubes (MWCNTs) and reduced graphene oxide (rGO) co‐decorated multifunctional core spurn yarn flexible strain sensor (CGY FSS). It was found that the well lapping between MWCNT and rGO endows sensor with high working range (&gt; 300%), while the helical structure of core‐spun yarn makes it sensitive to very tiny deformation (0.1%). To improve its dynamic durability, polydopamine (PDA) was used to improve the interface bonding force between yarn and conductive materials, which ensures the sensor conduct stable electrical signals during 10,000 stretching cycles test at 10% strain. These features made it suitable for human motion detection and structural health monitoring. Moreover, due to the abundant carboxyl groups on the carbon material surface and the employment of polymer‐based yarn, CGY FSS also showed good responsiveness to water vapor and acetone gas. It can be conceived that this as prepared strain sensor shows promising potential in smart device application with multiple response mechanism.

Rational design of three-in-one Pt/MnO2/GO hybrid nanozyme with enhanced catalytic performance for colorimetric detection of ascorbic acid and cysteine

In this work, a novel three-in-one Pt/MnO2/GO hybrid nanozyme with wide pH and temperature working range was rational prepared using simple hydrothermal and reduction strategy. The prepared Pt/MnO2/GO displayed enhanced catalytic activity than single active component due to the excellent conductivity of GO, the increased active sites, the increased electron transfer capacity, the synergistic effect between each component and the decreased binding energy for adsorbed intermediates. Combing chemical characterization and theoretical simulation calculations, the O2 reduction process on the Pt/MnO2/GO nanozymes and the generated reactive oxygen species in the nanozyme-TMB system were thoroughly illustrated. Based on the excellent catalytic activity of Pt/MnO2/GO nanozymes, a colorimetric strategy was proposed to detect the ascorbic acid (AA) and cysteine (Cys), and the experimental results indicated that detection range of AA was 0.35–56 μM with a LOD of 0.075 μM and detection range of Cys was 0.5–32 μM with a LOD of 0.12 μM. Good recoveries were achieved in the human serum and fresh fruit juice detection procedures, demonstrating the potential applications of Pt/MnO2/GO-based colorimetric strategy in complex biological and food samples.

A Simple and Efficient Strategy for Preparation of Flexible Strain Sensors Based on Marangoni Effect

The Marangoni effect is a phenomenon of mass transfer between two fluids with different surface tensions, which has been used in many fields. In this paper, we prepared ultrathin conductive films with graphene (GN) and carbon nanotubes (CNTs) based on the Marangoni effect. The Marangoni self-assembled film exhibited excellent properties, showing a conductivity of 8.3 kΩ·sq−1, a transparency of 74% at 550 nm and a thickness of 28 nm when the mass ratio of CNTs and GN was 1:1. The conductive films were transferred to flexible substrates twice and fabricated face to face as strain sensors. The 3M4910-based strain sensors, which were prepared with a simple process and high material utilization rate, exhibited good sensitivity (GF = 5.7), a wide working range (193%) and satisfactory cyclic stability. The PDMS-based GN sensor showed high sensitivity (GF = 34), a wide working range (78%) and excellent stability (ε = 10%, &gt; 8000 cycles). It has been proved that the sensors can be used to detect different joint movements of the human body and subtle movements, showing good application prospects in physiological signal detection.

Stretchable strain sensor based on HfSe2/LIG composite with high sensitivity and good linearity within a wide range

Flexible strain sensors based on nanomaterials have sparked a lot of interest in the field of wearable smart electronics. Laser induced graphene (LIG) based sensors in particular stand out due to their straightforward fabrication procedure, three-dimensional porous structures, and exceptional electromechanical capabilities. Recent studies have focused on LIG composites, however, it is still difficult to achieve great sensitivity and excellent linearity in a wide linear working range. Herein, a strain sensor with high sensitivity and good linearity is prepared in this work, which was realized by carbonizing the polyimide film coated with HfSe2 to obtain three-dimensional porous graphene nanosheets decorated with HfSe2 (HfSe2/LIG). After being transferred to the flexible substrate of Ecoflex, it exhibits high stretchability, hydrophobicity and robustness, and obtains excellent electromechanical properties. The HfSe2/LIG strain sensor demonstrated high sensitivity (gauge factor, GF ≈ 46), a low detection limit (0.02%), good linearity (R2 = 0.99) in a large working range (up to 30%), and a quick response time (0.20 s). Additionally, it exhibits good stability and consistent behavior across a large number of strain/release test cycles (>3000 cycles). With these benefits, the sensor can be used to monitor various limb movements (including finger, wrist and neck movements) and minute artery activity, and can generate reliable signals. Therefore, the HfSe2/LIG-based sensor has enormous potential for use in wearable intelligent electronics and movement monitoring.

АКТУАЛЬНІ НАПРЯМИ АРХІТЕКТУРНОЇ ОСВІТИ НА КАФЕДРІ ДАС НУ «ЛЬВІВСЬКА ПОЛІТЕХНІКА» В УМОВАХ ВІЙНИ ТА ПІСЛЯ ПЕРЕМОГИ

As of the beginning of 2023, the destruction of many facilities and the environment as a result of the war unleashed by the Russian aggressor in Ukraine has made it urgent to rebuild everything lost not only in peacetime, after the victory, but also now, when active hostilities are underway. The challenge of today is to quickly and effectively restore everything that has been destroyed and create new opportunities for the near and far future. A lot has been lost: more than 149.3 thousand residential buildings; 3 thousand secondary, pre-school and higher education institutions; almost 1500 cultural, sports and tourism facilities; about 100 religious sites; 330 hospitals; 595 administrative buildings and much more. Our society will never be able to fully restore the architecture and environment of Ukraine, relying only on measures initiated by the authorities from above. Financial and organizational support alone is not enough to revive everything destroyed by the war in Ukrainian cities and towns. And the architecture of Ukraine can be restored not so much by foreign architectural stars as by our own, Ukrainian creators of architecture. Architectural education is also of great importance in this process. After all, senior students will be the direct implementers of the ideas that are being generated today. Therefore, their training, both theoretical and practical, should be developed now in the process of studying at higher education institutions. The article highlights a wide range of works that were performed by students of the Department of Architectural Environment Design as part of their training and diploma design for the needs of rebuilding Ukraine after the Russian invasion. The article also emphasizes the relevance of using tasks related to the restoration of public housing and landscape objects in the educational process of training future personnel, whose professional activity will begin at the beginning of the main phase of the renovation of cities and settlements. This practice will allow students to better adapt and become competitive in the current labor market.

Polyphony in Vadim Salmanov's a cappella choral work

The author examines in detail the revival of ancient choral genres and forms that corresponded to the aesthetic trend in the Russian musical culture of the second half of the twentieth century. The subject of the study is the stylistic features of Vadim Salmanov's polyphonic writing. The object of the research is the choral heritage of V. Salmanov's a cappella from the point of view of integrating new compositional techniques and polyphony. Special attention is paid to polyphonic techniques in the concert for the a cappella choir "Lebedushka". The author examines in detail the dramaturgy and architectonics of the choral concert "Lebedushka", as well as such aspects of the topic as: polyphonic methods, including imitation polyphony and heterophony, writing techniques of the twentieth century (sonorica, aleatorica). V. Salmanov's works clearly demonstrate that the genre of choral concert occupies one of the main places in the history of Russian choral creativity a cappella. It is proved that in the genre hierarchy, it is the choral concert that plays the leading role in terms of the number of artistic discoveries. The research methodology is based on the analysis of historical materials, a wide range of works by Russian musicologists concerning the history and theory of musical genres, polyphonic writing techniques and performing practice. Through the synthesis of research methods, including musicology and choral studies, the parameters of musical composition are revealed. The main conclusions of the conducted research are the paradigm of artistic connections of traditional polyphonic techniques with modern means of compositional writing. The novelty of the research lies in the fact that for the first time polyphonic techniques in modern choral composition are analyzed from the standpoint of musicology and choral studies. A special contribution of the author to the disclosure of the topic is the study of V. Salmanov's choral concert "Lebedushka", which had not previously been the object of special research from the point of view of polyphony. In this work, the presentation of musical material itself, as well as polyphonic methods of working with it, are conducted under the auspices of the search for a new sound characteristic of modern music. Attention is focused on the need to study the issues related to the role of polyphony in modern choral composition, due not only to the general artistic and historical potential of choral culture as a whole, but especially its great importance in modern musical art.