Wide Working Range Research Articles

Wearable LIG Flexible Stress Sensor Based on Spider Web Bionic Structure

Bionic structures are widely used in scientific research. Through the observation and study of natural biological structure, it is found that spider web structure is composed of many radial silk lines protruding from the center and spiral silk lines surrounding the center. It has high stability and high sensitivity, and is especially suitable for the production of sensors. In this study, a flexible graphene sensor based on a spider web bionic structure is reported. Graphene, with its excellent mechanical properties and high electrical conductivity, is an ideal material for making sensors. In this paper, laser-induced graphene (LIG) is used as a sensing material to make a spider web structure, which is encapsulated onto a polydimethylsiloxane (PDMS) substrate to make a spider web structured graphene flexible strain sensor. The study found that the stress generated by the sensor of the spider web structure in the process of stretching and torsion can be evenly distributed in the spider web structure, which has excellent resonance ability, and the overall structure shows good structural robustness. In the experimental test, it is shown that the flexible stress sensor with spider web structure achieves high sensitivity (GF is 36.8), wide working range (0–35%), low hysteresis (260 ms), high repeatability and stability, and has long-term durability. In addition, the manufacturing process of the whole sensor is simple and convenient, and the manufactured sensor is economical and durable. It shows excellent stability in finger flexion and extension, fist clenching, and arm flexion and extension applications. This shows that the sensor can be widely used in wearable sensing devices and the detection of human biological signals. Finally, it has certain development potential in the practical application of medical health, motion detection, human-computer interaction and other fields.

A flexible pressure sensor with highly customizable sensitivity and linearity via positive design of microhierarchical structures with a hyperelastic model

The tactile pressure sensor is of great significance in flexible electronics, but sensitivity customization over the required working range with high linearity still remains a critical challenge. Despite numerous efforts to achieve high sensitivity and a wide working range, most sensitive microstructures tend to be obtained only by inverting naturally existing templates without rational design based on fundamental contact principles or models for piezoresistive pressure sensors. Here, a positive design strategy with a hyperelastic model and a Hertzian contact model for comparison was proposed to develop a flexible pressure sensor with highly customizable linear sensitivity and linearity, in which the microstructure distribution was precalculated according to the desired requirement prior to fabrication. As a proof of concept, three flexible pressure sensors exhibited sensitivities of 0.7, 1.0, and 1.3 kPa−1 over a linear region of up to 200 kPa, with a low sensitivity error (<5%) and high linearity (~0.99), as expected. Based on the superior electromechanical performance of these sensors, potential applications in physiological signal recognition are demonstrated as well, and such a strategy could shed more light on demand-oriented scenarios, including designable working ranges and linear sensitivity for next-generation wearable devices.

Robust and flexible bacterial cellulose-based thermogalvanic cells for low-grade heat harvesting in extreme environments

Harvesting the ubiquitous low-grade heat based on thermoelectric materials is an effective approach to ensure sustainable development. Quasi-solid thermogalvanic cell based on hydrogel has attracted considerable attention. However, challenge arise from the limited working temperature range and poor mechanical properties, thus severely restrict their long-term stability and application scenarios, especially under harsh environment. Herein, a robust, flexible and eco-friendly quasi-solid thermogalvanic cell is reported based on natural polymer bacterial cellulose confined with Fe(CN)63−/4− redox couple and hygroscopic salts. The as-fabricated bacterial cellulose-based thermogalvanic cell (BC-TGC) possesses excellent mechanical properties, exhibiting a tension strength of 3.4 MPa, a Young's modulus of 2.58 MPa and a high toughness of 644.6 KJ m−3. The introduction of hygroscopic salts (LiBr) endows the BC-TGC with excellent anti-drying and anti-freezing properties. The thermoelectric performance of BC-TGCs was investigated thoroughly, which could generate steady electricity under a small temperature gradient in a wide working range of −50 to 50 °C. The multifunctional applications of the BC-TGC were demonstrated, indicating that they could adapt to different temperatures and harsh environments, which greatly expanded the application scenarios of TGC. We expect that this study will provide an effective solution for portable, flexible and robust power supplies fabrication for low-grade heat harvesting.

A GC-FID validated method for detection and quantification of ethylene oxide in urine bags

The urine bag is a thermo-labile medical-hospital device used in clinical/surgical procedures in urine drainage and collection. As it is a thermolabile material, it is commonly sterilized by ethylene oxide, a highly toxic, mutagenic and carcinogenic cyclic ether gas. Currently, several countries require, through documents and standards, the quantification of ethylene oxide in medical and hospital devices. Thus, this work describes the development and validation of a method employed for the quantification of ethylene oxide (ETO) in urine bags. The method was developed based on the guidelines of ISO 10993-7, ANVISA and INMETRO. The work range, linearity, limits of detection and quantification, repeatability, intermediate precision and selectivity were evaluated. Statistical tools such as Levene's test, Grubbs, residual analysis, F-test of two variances, paired sample T test and ANOVA table, were also applied to evaluate the method. The linearity of the work range (10 – 400 mg.L-1) showed an adequate correlation coefficient (r > 0.9993), with a homoscedastic profile with absence of outliers while the limit of detection and quantification were 1,95 and 6,5 mg.L-1 respectively. After validation, 45 samples of urine bags of different batches were evaluated, which demonstrated levels of ETO below the limit of detection (1,95 mg.L-1). The results highlight a simple method that meets several regulations with a wide working range, high sensitivity and capability to quantify ETO not only in urine bags but also in other medical devices.

ATR-FTIR AND UV-VIS AS TECHNIQUES FOR METHANOL ANALYSIS IN BIODIESEL-WASHING WASTEWATER

Methanol present in wastewater from the biodiesel industry can become an atmospheric pollutant and an environmental liability of effluents. This article proposes the development and performance evaluation of two spectroscopic methods, ATR-FTIR and UV-Vis, to identify and quantify methanol in aqueous media. The results of both ways exhibited remarkable linear detection, with a coefficient of determination (r2) &gt; 0.99, wide working range, and relative standard deviation (RSD) &lt; 12%. In the ATR-FTIR method, the detection and quantification limits were 0.064 and 0.128% m V-1, respectively. The UV-Vis method presented lower limits (0.005 and 0.008% m V-1, respectively). Finally, the methods were successfully applied to quickly and sensitively quantify the methanol present in wastewater from biodiesel-washing in a wide concentration range of 0.008-0.641% m V-1. Therefore, we evidenced the feasibility of spectroscopic methods in quality control for identifying and quantifying methanol in aqueous solution, with potential for application in biodiesel production industries and research laboratories. Mainly by ATR-FTIR, in the region of 1300-900 cm-1, as it proved to be more environmentally friendly, faster, and cheaper than the GC-FID method.

РОЗРОБЛЕННЯ КОНЦЕПЦІЇ ПОЗИЦІЮВАННЯ ОРГАНІЗАЦІЙ ТУРИСТИЧНОЇ СФЕРИ

The article is devoted to the justification of the process of strategic positioning of tourism positioning firms. The economic and social crisis of recent years has seriously affected the development of the tourism industry, causing the need for qualitative changes and improvement of the structure of the tourism industry, improving the efficiency of management and the quality of services. At the same time, the issue of improving the system of strategic marketing planning in the tourist organization, which makes it possible to concentrate the available limited resources on the most important strategic directions, and to ensure the flexibility and maneuverability of their use, becomes especially relevant. Ensuring the competitiveness of the organization is impossible without the development and implementation of an effective marketing positioning strategy. Modern business in a highly competitive economy can be successful if the target audience is correctly selected and the organization of systematic work is done to satisfy and, ideally, anticipate their requests. To organize relations with its target audience, a travel company must pay serious attention to the positioning of itself and its products or services. Positioning is a complex phenomenon and, despite the presence of a wide range of scientific works, the study of its conceptual foundations, directions and methods remains relevant from both a theoretical and a practical point of view. The research proposed and substantiated the author's vision of the peculiarities of the positioning of a tourist company with an emphasis on the characteristics of the tourist product and demand, as well as the nature of competition, as well as proposed approaches to the positioning of tourist companies at two levels: tourist product and tourist operator. The positioning strategy is successfully used in many organizations of the tourism business as it allows you to gain a decisive advantage over competitors, which is especially important for the tourism market, which is characterized by a high level of competition and the provision of similar services that often do not have unique characteristics.

The functions of literary allusions in Old Possum’s Book of Practical Cats by T. S. Eliot

This article deals with the functions of literary allusions in Old Possum’s Book of Practical Cats by T. S. Eliot. The material of the study is the book of verses included into the annotated anthology The Poems of T. S. Eliot. Vol. 2. Practical Cats and Further Verses (2015) compiled and edited by the leading contemporary Eliot scholars, British-American researcher Sir Christopher Ricks and renowned British critic and publisher Jim McCue. In this paper, the author considers different types of allusions in T. S. Eliot’s poems and determine their specificity. This has required using cultural historical approach and methods of literary structural analyses. The purpose of the study is to confirm that the intertextuality of Old Possum’s Book of Practical Cats is represented by a new type of allusiveness, which is an important element of modernist aesthetics. Intertextuality in T. S. Eliot’s book of verses is a complex system of connections between texts and phenomena of various cultural and historical layers. Allusions change the status of the texts of the book, make them heterogeneous and help to expand their figurative structure. A characteristic feature of Eliot’s modernist allusion is its multi-composition where one and the same image can be correlated to various literary texts and cultural eras. The intertextuality of Old Possum’s Book of Practical Cats proves that these verses were addressed for an adult audience as well, since only an intellectually “savvy” reader familiar with a wide range of literature and art works, various cultural traditions and historical eras is able to understand the different textual levels and the artistic intentions of the poet.

Qualification of the Residential House Administrator in the Sustainable Housing Conservation Context

Abstract Administration of residential houses, in accordance with legal regulations, is a complex process that includes different important functions. Such functions encompass performing regular maintenance, sanitary cleaning and required repairs, as well as thorough planning and organisation, strict documentation and monitoring. Moreover, administration of residential houses includes communication with residents and cooperation with public institutions to ensure protection of rights and interests of apartment owners. Professional administration of residential houses requires a complex, responsible and very specific approach, covering a wide range of complex works. Housing stock administration is a thoroughly elaborated process with specific schedules and goals. It covers not only maintenance of engineering works and the building, but also administration of the surrounding territory and common-use premises. Moreover, it covers a precise administration process and efficient communication with residents of the building, and solution of routine administrative cases. An administration contract with a specialist in this field is not just a means but a tool by using which owners of a residential house, i.e., apartment owners, fulfil the obligations stipulated by law with regards to efficient administration of the residential house. Choosing the right administrator is important for the owner because it determines the sustainable conservation cycle of the building. A person is eligible to perform administration tasks in a multi-apartment residential house, when having obtained the required professional education in administration of residential houses.

A Simple Method for Determination of Chloroquine Based on Electrogenerated Chemiluminescence

Chloroquine is a drug belonging to the aminoquinoline family that is widely used for treating diseases such as lupus, cancer, and malaria. In this sense, the present work describes the development of a simple method based on electrogenerated chemiluminescence (ECL) and a screen-printed carbon electrode (SPE) modified with carbon black for chloroquine determination. The carbon black modified SPE was characterized by scanning electron microscopy, Raman spectroscopy, cyclic voltammetry and linear sweep voltammetry to obtain the ECL-potential curves. The ECL method is based on the chemiluminescence resulting from the interaction between chloroquine and the tris(2’2-bipyridyl) ruthenium(II) complex. Under optimized experimental conditions, the method showed a wide linear working range between 0.5 and 500 µmol L-1. The method presented good precision and accuracy in drug samples used in the treatment of malaria and artificial urine sample, showing recovery values from 100 to 103% and 99 to 103%, respectively.

The Long Century of the Ottoman Weapons: Transformation of the Equipment of the Ottoman Ground Forces during the Modernization of the 19th Century

The paper explores the development of the material and technical basis of the Ottoman ground forces during the period of a widescale modernization and implementation of Western technical innovations (1826—1880). The paper scrutinizes the activities of the most important Ottoman industrial centers, which provided all kinds of troops with necessary supplies, and firearm purchases from Belgium, Great Britain, France and the USA. The source base of the research includes a wide range of works of the Ottoman historians and military leaders, books of the British and French authors and archive materials containing the notes of the Russian military informers. The multifaceted analysis of the Ottoman military transformations revealed a controversial nature of the modernization. On the one hand, the reformers successfully accomplished the rearmament programme. By the end of the reforms the majority of the Ottoman regular troops had possessed the latest British and American rifles and cannons manufactured by Krupp factory. On the other hand, the modernization of the equipment and industrial centers worsened the financial position of the Ottoman Empire and caused a rapid growth of the military expenditures that composed a significant part of the Ottoman state debt. Several unsuccessful attempts of organization of the military production strengthened the dependence of the Ottoman empire on imports from Europe and America. The technological progress chase increased the Ottoman military potential, however its cost weakened economic and, as a consequence, political position of the state.

Sensitivities of Presentation and Portrayal in Media Art

As scientific knowledge and technological prowess have grown, so too has the prevalence of cutting-edge innovations like virtual reality. Virtual reality (VR) technology is now being used in the digital media art industry. Because of the explosion of digital media art, animators now have more room to experiment with new ideas and techniques, bringing their work closer to the realities of viewers' everyday lives. So that they feel like an integral part of the conversation throughout. Artistic interactivity between the spectator and the moving pictures that were created for the screen is possible. The audience's traditional role as observers has shifted to one of active participants and witnesses. Artists and computers now work together to finish works and applications using digital media technology, which means that the production of such tools is no longer a one-way process. There is no denying that computer technology has had a profound impact on the visual representation of a wide range of works of digital media art, with animation design bearing the brunt of this effect. Modern animation design may benefit from the use of digital media art, which can deepen the meaning behind it and improve its aesthetic. At the same time, it may encourage the growth and development of digital media art and lead to shared progress.

Growth of diazonium-functionalized ZnO nanoflakes on flexible carbon cloth for electrochemical sensing of acetone in the liquid phase.

Simple detection of acetone is indispensable due to its health and environmental concerns. Surface-modified electrodes are promising for the detection of acetone. In the present study, the facile fabrication of ZnO nanoflakes on carbon cloth (CC) is reported. The electrode was fabricated by decorating the CC with ZnO nanoparticles (ZnO NPs), followed by the hydrothermal treatment and modification with diazonium salt using linear sweep voltammetry (LSV) forming ZnO nanoflakes (ZnO NFs) on ZnO NPs/CC. The as-prepared ZnO/CC electrode was used for the detection of acetone at room temperature using cyclic voltammetry. Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) analyses were used for the chemical and physical characterization of the CC before and after each modification step. The obtained data manifested that ZnO NFs functionalized with diazonium salt increased the roughness of the CC surface, which was advantageous to promote the interaction between CC and acetone target. The modified sensing platform showed excellent performance in terms of the wide working range (0.1-2000 ppm) and low detection limit (0.03 ppm), making it a promising and cost-effective sensor of acetone in the liquid phase.

Токумаланы Жагъафарны чыгъармачылыгъыны суратлау аулакълары

The article examines the literary heritage of the famous Balkarian writer, playwright Zhagafar Tokumayev. The main purpose of the work is to fully present the panorama of the creative work of the master of the artistic word, to determine its role in the evolution of national written literature. The article is preceded by a short autobiographical reference focusing on the influence of the writ-er's life experience on the formation and development of his artistic consciousness. Tokumayev's creativity is considered from the point of view of genre, thematic diversity, the ethnocultural specificity of his works is determined. Analysis of the author's aesthetic experience in small and medium epic forms (stories "Agronomist", "Mistake", "Courage", "Investigator's Story"; the sto-ries "The fate of the orphan", "Descendants of the sleds", "The Pass") it shows a wide thematic range (istroic, moral, social, household, detective) of works, reveals characteristic artistic features (the connection of times, the evolution of consciousness of the main actors at the sharp fractures of history and in extraordinary life circumstances). The article focuses on the trilogy of J. Toku-maeva's "Dagger of Revenge", recognized as the first experience of artistic cyclization in Balkar novelistics. The constructive role of Zh is also noted. Tokumaeva in the development of drama and stage art (comedies "Imaginary authority", "Shadows", "Jamilya", "Chonai marries", included in the "golden fund" of the repertoire of the Balkarian State Drama Theater named after K. Kuli-yev). The versatility of the writer's talent is evidenced by children's prose ("The Stories of Aldar-bek from Kurnayat"), humorous miniatures ("Mocker Chonai"). As a result of the study, the au-thor's desire throughout his creative life to expand genre-thematic horizons in understanding artis-tic reality, which subsequently contributed to the enrichment of the spiritual culture of the Balka-rian ethnic group.

A novel composite polymer electrolyte containing the lithium-ion conductor Li3Zr2Si2PO12 synthesized by cationic-exchange method for solid lithium metal batteries

The composite polymer electrolyte (CPE) is one of the most promising approaches to develop solid-state lithium metal batteries (SSLMBs) because of its easy processing, flexibility, and high ionic conductivity. In this work, NASICON-type Li3Zr2Si2PO12 (LZSP) synthesized by a skeleton-retained cationic exchange method is first introduced into poly(vinylidene fluoride) (PVDF) based polymer electrolyte. The fabricated LZSP/PVDF-CPE presents a high lithium ionic conductivity (2.28×10−4 S cm−1) at room temperature and a wide electrochemical window (> 5.2 V vs Li+/Li), which can match high-voltage cathode materials. Also, LZSP/PVDF-CPE has sufficient mechanical strength and excellent stability with lithium. For further illustration, the LiNi0.5Co0.2Mn0.3O2|LZSP/PVDF-CPE|Li SSLMBs are assembled and have achieved satisfactory cycling performance and rate stability at 25 °C, even at a wide working range within 2.8–4.5 V. Our study shows that the LZSP/PVDF-CPE is promising in solid-state lithium metal batteries.

Летопись хоринских бурят Рабжи Санжиева: предварительные сведения

Introduction. The introduction of new sources characterizing traditions of Buryat chronicle writing into scientific circulation remains an urgent task of Mongolian studies. Dozens of works and their various copies and editions are still there to be explored. The article precedes a further study and translation of a voluminous historical chronicle of the Aga and Khori Buryats. Goals. The study attempts a brief overview of the chronicle’s contents and approaches some peculiarities traced in its text. Materials and methods. The analysis of Rabzhi Sanzhiev’s writing involves a wide range of Buryat historical works — both chronicles and archival documents. The historical comparative and chronological methods prove instrumental in systematizing the data contained, while tools of textual and source studies have made it possible to delineate the author’s text proper. Results. The work identifies an extensive range of sources and the chronicle’s structure according to which R. Sanzhiev’s narrative be conventionally divided into a number of large sections, namely: Shirab-Nimbu Khobituev’s chronicle; copies of official documents; historical works by T. Toboev, D. Zayaev, S. Vandanov, A. Ochirov; and the author’s text. Conclusions. R. Sanzhiev’s writing is a major work of the historical documentary genre. The author undertook painstaking efforts to meticulously clarify data included in Shirab-Nimbu Khobituev’s chronicle and supplement certain facts and data, introduce additional findings from various sources. The continuation of Khobituev’s chronicle — despite the compiled facts are fragmented enough — acts as an independent composition. Archival documents on the history of Buryat self-governance and Buddhism, folklore texts, chronicles and legends included by the author into the narrative are of particular value.

The Computed Tomographic Imaging Spectrometer based on metamaterial surface

Computed Tomographic Imaging Spectrometer (CTIS) has the advantages of both computed tomography technology and snapshot spectroscopy and has potential applications in many fields. However, the development of CTIS has been limited by the volume issues of key components. In consideration of the compact structure of the metamaterial, an all-dielectric metamaterial array is studied as an alternative to optimize the structure of CTIS. The array can be used for snapshot-type optical imaging, with a wide working range of 550 nm∼1000 nm. At the same time, the system design and simulation technology are studied by using the array, which provides a useful reference for the development of micro imaging spectrometer based on metamaterial.

A fluorescein-based fluorescent probe for real-time monitoring hypochlorite

Hypochlorite is an important reactive oxygen species in environment and pathophysiological processes. Abnormal level of ClO− can be destructive and lead to many diseases. Herein, to real-time and sensitively monitoring ClO−, a fluorescein-based fluorescence turn-on probe for ClO− in almost pure PBS buffer solution was successfully developed. After sensing hypochlorite, the spirolactam ring of the probe was opened and fluorescence at 525 nm greatly enhanced (∼1800 fold). The probe has a low detection limit (9.6 nM), short response time (∼1 min) and wide pH work range (5.0–9.0). Furthermore, the probe has been successfully applied to detect ClO− in disinfectant and actual water samples. Based on its fast response rate and almost pure buffer detection condition, the probe can be used to real time monitor ClO− in actual water environment.

An angle-compensating colorimetric strain sensor with wide working range and its fabrication method

The visual response is one of the most intuitive principles of sensors. Therefore, emission and change of the colors are widely studied for development of chemical, thermal and mechanical sensors. And it is still a challenging issue to fabricate them with a simple working mechanism, high sensitivity, good reliability, and a cost-effective fabrication process. In this study, we propose a mechanical strain sensor, which has 2D photonic crystal structures in nanoscale on stretchable polydimethylsiloxane (PDMS) substrate. Due to the periodic nanostructures, the surface of the sensor produces structural colors. And when it is stretched, the periodicity of the nanostructures changes, which results in the shift of the colors. Multiple nanostructures with different periodicities are integrated on the sensor in order to extend the working range up to 150% with high sensitivity. In addition, reusable and robust molds, which are fabricated by self-assembly of nanoparticles, are used for multiple replications of sensor substrates. Thus, the fabrication process of this study is believed to be potential for possible industrial manufacturing. This study is expected to contribute to strain sensors in the future for the applications of health care, infrastructure monitoring, soft robotics, and wearable devices.

Label free optical biosensor for insulin using naturally existing chromene mimic synthesized receptors: A greener approach

We currently reporting a simple and first label free optical insulin biosensor using a novel cum naturally existing Chromene mimic receptors via one pot greener methodology. Among synthesized 4H- Chromene derivatives, 2-amino-5,7-dihydroxy-4-(4-nitrophenyl)-4H-chromene-3-carbonitrile (Compound 1c) is showed a very good colorimetric response for insulin within the linear range of 20 fM −500 pM along with theoretically measured LOD of 15.38 fM based on the increment in absorbance. Meanwhile 2-amino-5, 7-dihydroxy-4-(pyren-2-yl)-4H-chromene-3-carbonitrile (Compound 1a) is depicted an excellent quenching in fluorescence response for insulin with LOD of 7.07 fM and along with wide working range from 10 fM −600 pM. The developed biosensor is tested for the detection of insulin in human blood serum using direct as well as standard addition method and the recovery results are showed a very good agreement with standard clinical chemiluminescent assay method. Hence, this developed biosensor is more reliable for clinical detection of Insulin and so a good analytical method for Diabetes diagnosis within a short period of time.

Rational designed microstructure pressure sensors with highly sensitive and wide detection range performance

• High sensitivity (26.55 kPa −1 ) and wide work range (0.9 Pa-140 kPa) pressure sensor was demonstrated. • Micro-nano hierarchical structure sponge surface with random uneven pattern. • PDMS sponge fabricated via mixed sacrifice template and electrostatic self-assembly methods. • The pressure sensor has great potential for healthcare and human-machine interfaces. Highly sensitive pressure sensors are often deployed in human-machine interaction area, touch screen and human motion detection. However, there are still great challenges to fabricating with high sensitivity pressure sensor with wide-range detection. Herein, we developed a new strategy to fabricate a highly sensitive pressure sensor using sandpaper and improve its detection range using a sacrificial template. It was the fthatirst time to combine microstructure processing with the sacrificial template method to fabricate pressure sensor. The microstructure of sandpaper endowed the sensor with high sensitivity, and the elastic substrate enhanced the sensor ability to resist high pressure without being damaged. The fabricated sensor device exhibits a superior sensitivity of 39.077 kPa −1 in the range from 50 kPa to 110 kPa with a broad linear response. Remarkably, high pressure ceiling (<160 kPa) ensures that the sponge could be applied in different practical conditions to monitor a range of subtle human motions including finger, wrist bending, and pulse. For applications, the sensor device can not only detect the foot stepping behavior (0.7 MPa) but also produce an obvious response to an extremely slight paper (9 mg, ∼0.9 Pa). The successful preparation of this micro-structured elastic sponge material provided new ideas for exploring its potential applications in pressure sensors and flexible wearable electronic devices.