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The kinematic model of the working device of three-section boom excavator is established by using D-H method, the hydraulic cylinder of upper arm is segmented, and the envelope diagram of the three-section boom excavator is drawn with MATLAB by using superposition method. The simulation results show that the error between the simulation value and the sample value is within a reasonable range. The values of the main operating parameters and the corresponding change law when the hydraulic cylinder of upper boom is the shortest and the longest are analyzed, and the mathematical relationship between the length of the hydraulic cylinder of upper arm and the main operating parameters is fitted. The research results show that the main operating parameters above the horizontal plane increase with the increase of the length of the hydraulic cylinder of upper boom, while the main operating parameters below the horizontal plane decrease with the increase of the length of the hydraulic cylinder of upper boom. [ABSTRACT FROM AUTHOR]

In this work, an air-cooled, single effect solar-driven absorption system is being evaluated from the point of view of 1 st and 2 nd thermodynamic principles for two different applications: absorption chiller and heat pump. One of the most widely used working pairs, LiBr-H 2 O, is applied in this study due to its high performance in the absorption cycle. Their performance is compared with another working pair Carrol-H 2 O (Carrol contains LiBr and EG -Ethylene glycol- with a mass ratio of 4.5:1). The Carrol solution has the advantage of reducing the crystallization risk at the high concentration solution which enters the absorber. The numerical modelling was implemented on a modular object-oriented simulation platform (NEST platform tool), which allows linking different components, considered objects. In the simulations performed, the heat source temperature in the system is in the range of 70-90 ∘ C, and the inlet temperature at evaporator secondary circuit at chiller application is fixed in two values, 9 ∘ C and 14 ∘ C, and for heat pump application in 0 ∘ C and -5 ∘ C. Moreover, EG is added to the evaporator at heat pump application to prevent the refrigerant water from freezing below zero. The studied mass concentration range of EG of 10-40%. The result shows the C O P of an absorption chiller and heat pump are around 0.7 and 1.6, respectively, and the C O P EX values are 0.2-0.6 at chiller application and 0.5-1.5 at heat pump application. When compared with LiBr system, Carrol system has about 6.4% higher C O P , about 6.3% higher C O P EX , and a decrease of about 19% of cooling capacity. In the heat pump application, the heat source temperature should be lower than 90 ∘ C, and EG concentration at evaporator has been chosen as 30% as an optimal value. According to the operation condition, this EG concentration has been determined to avoid freezing in the evaporator in the studied working range. However, too much EG significantly decreases the pressure in the evaporator and increases the viscosity, hence will increase the maintenance of equipment as more vacuum tightness is required.

The ejector driven by the high-pressure gas potential energy from the hydrogen storage tank can reliably recirculate the unconsumed hydrogen in the proton exchange membrane fuel cell (PEMFC) system. However, the fixed-geometry ejector cannot maintain consistently high performance among the whole power output range in the PEMFC system due to its shortage of limited operating range. In this paper, a coaxial two-nozzle ejector, satisfying the requirements of the PEMFC system under different power outputs, is developed for hydrogen recirculation. The proposed ejector is investigated numerically based on an experimentally verified simulation model to reveal the flow distribution and predict its performance. The simulation results show that the proposed ejector can work in a wide power range of 17.90–84.00 kW within a suitable supply hydrogen pressure range of 4–7 bar. More importantly, the ejector can not only maintain a recirculation ratio above 0.9 in the wide output power range but a high recirculation ratio greater than 2.0 in the low power output. The proposed ejector broadens the working range of a single ejector used in the PEMFC system, which significantly promotes the development of fuel cell being widely adopted in automobiles.

Flexible strain sensors have received intensive attention owing to their wide application prospects in the fields of wearable, personal electronics, and intelligent robotic systems. But it is a huge challenge for them to possess high sensitivity, fast response, wide sensing range, and superior durability synergistically. In order to solve these issues, we prepared a new type of buckypaper with excellent mechanical properties (elongation at break of about 22%) and electrical conductivity (33 S/cm) by filtering carbon nanotube (CNT) aqueous dispersion mixed with a small amount of natural rubber latex (NR), named natural rubber-buckypaper (N-BP). By taking advantage of the robust N-BP, an NR/N-BP/NR strain sensor was creatively constructed by sandwiching the N-BP with two NR layers using the casting-curing method. The NR/N-BP/NR sandwich strain sensor showed a very high gauge factor value (2280), ultrashort response time (21 ms), very large sensing range (500%), and satisfactory sensing stability (2000 cycles at 100% strain). As for practical application, this NR/N-BP/NR strain sensor could accurately capture large or subtle human body movements, such as limb joint movements and facial movements, and could even distinguish the pronunciation of different English words. As a whole, the NR/N-BP/NR sandwich strain sensor exhibited promising applications in wearable electronics. The NR/N-BP/NR sandwich strain sensor with wide working range and high sensitivity based on the excellent performance of N-BP.

Wearable strain and temperature sensors are desired for human-machine interfaces, health monitoring, and human motion monitoring. Herein, the fibrous mat with aligned nanofibers of ionic liquid (IL)/thermoplastic polyurethane (TPU) ionogels is fabricated via an electrospinning technique. The resultant fibrous mat is cut into a rectangle specimen and electrodes are loaded along the direction perpendicular to the nanofiber orientation to design a high-performance multimodal sensor based on an ionic conducting mechanism. As a strain sensor, the obtained sensor exhibits a wide strain working range (0-200%), a fast response and recovery (119 ms), a low detection limit (0.1%), and good reproducibility because of the reversible and deformable ionic conductive pathways of the sensor. Moreover, the sensor also exhibits excellent temperature-sensing behaviors, including a monotonic thermal response, high sensitivity (2.75% °C-1), high accuracy (0.1 °C), a fast response time (2.46 s), and remarkable repeatability, attributable to the negative temperature coefficient behavior of the IL/TPU fibrous mat. More interestingly, the IL/TPU fibrous sensor possesses good breathability, which is desired for wearable electronics. Because of these excellent sensing capabilities in strain and temperature, the sensor can not only monitor tiny and large human motions but also detect respiration and proximity, exhibiting enormous potential in wearable electronics.

This paper presents a position sensor based on a novel configuration of linear variable differential transformer. Design and optimization of the position sensor using finite element method are presented. The measurements are also conducted to validate experimentally the sensor performance. The sensor has short air core coils and long magnetic armatures. The axis of the rectangular excitation coil and two antiserially connected rectangular pick up coils is perpendicular to the motion direction of the position sensor. The coils are located between two parallel silicon steel laminations serving as the armatures. The position sensor is optimized with compromise between minimization of nonlinearity error and maximum sensitivity. The main advantage of the proposed position sensor is the small ratio of coils dimensions to the working range. The position sensor is operated for excitation frequencies of 500 Hz, 1000 Hz, and 2000 Hz. The maximum nonlinearity error is less than 1.5% for the theoretical results and it is less than 2% for the measured results in ±90 mm position range.

Background A novel gradient, high-sensitive and specific stability-indicating reverse-phase HPLC method was developed and validated for quantitative purpose of known, unknown and degradant impurities profiling for diltiazem hydrochloride tablets. The impurities were separated on the Zorbax RX C8 column (150 mm × 4.6 mm, 5 μm) with mobile phase-A consisting of a mixture of 0.05 M sodium dihydrogen phosphate monohydrate buffer pH 3.0 and methanol in the ratio 800:200v/v and mobile phase-B consisting of acetonitrile with a flow rate of 1.0 mL min−1. The column compartment was maintained at 35 °C, and the detection wavelength was 240 nm. Diltiazem hydrochloride, its known impurities and unknown impurities have been well resolved from each other. Results The linearity of the method has been demonstrated across the concentration range of 0.18 to 5.65 µg mL−1 for EP impurity-F with correlation coefficient R2 greater than 0.99. Recovery of method was proved from LOQ to 150% for known and unknown impurities with respect to test concentration and found in between 80 and 120%. Forced degradation study and specificity experiment results with mass balance proved the stability-indicating nature of the method and separated all known, unknown impurities and degradants from each other as well as from main drug component (diltiazem hydrochloride). The mass balance for stress study was found in between 95 and 105%. Conclusion Newly developed analytical method was validated as per ICH Q2 (R1) guidelines “Validation of analytical procedure” and found linear, accurate, specific, robust and precise in the established working range.

This report summarize performance of the Fabry-Perot refractometers developed in work package 1 in the 18SIB04 QuantumPascal project. The report first briefly introduces the concept of performance in terms of precision, accuracy, and working range. Thereafter each of the systems that have been developed by the partners is shortly described and their contribution to the overall performance in terms of uncertainty is highlighted. From the combined results of the systems, it can be concluded that the target uncertainties have been reached., Acknowledgement: This project '18SIB04 QuantumPascal' has received funding from the EMPIR programme co-financed by the Participating States and from the European Union's Horizon 2020 research and innovation programme. More information can be found on the website: https://www.ptb.de/empir2019/quantumpascal/

The mechanism of the fluorescence quenching of the CQDs by warfarin was determined and based on this study a simple, low cost and highly sensitive nanosensor was developed for determination of Warfarin in plasma samples. The carbon quantum dots with 3.5 µs lifetime (halflife of 2.4 µs) were synthesized by hydrothermal method and characterized. The fluorescence rate constant of 4.5 × 104 s−1 and quenching rate constant of 6.18 × 104 s−1 (from 10 μM warfarin that result in 17% lifetime reduction) was calculated. High quenching efficiency results in 21.63 L mmol−1 Stern–Volmer constant and the study of pH and temperature also confirm the dynamic quenching mechanism. The second order rate constant of 6.18 × 104 L mmol−1 s−1 was obtained for collisions between CQDs and warfarin. Based on this mechanism, a simple, low cost and very sensitive warfarin nanosensor was developed with calibration sensitivity of 21.63 L mmol−1, working range of 0.10 – 12.00 μM and detection limit of 0.01 μM.

Microstructures play a dominant role in flexible electronics to improve the performance of the devices, including sensitivity, durability, stretchability, and so on. However, the complicated and expensive fabrication process of these microstructures extremely hampers the large-scale application of high-performance devices. Herein, we propose a novel method to fabricate flexible graphene-based sensors with a 3D microstructure by generating laser-induced graphene (LIG) on the 3D printed polyether ether ketone corrugated substrate, which is referred to as CLIG. Based on that, two integrated piezoresistive sensors are developed to monitor the precise strain and pressure signals. Contributed to the 3D corrugated graphene structure, the sensitivities of strain and pressure sensors can be up to 2203.5 and 678.2 kPa-1, respectively. In particular, the CLIG-based strain sensor exhibits a high resolution to the microdeformation (small as 1 µm or 0.01% strain) and remarkable durability (15,000 cycles); meanwhile, the pressure sensor presents a remarkable working range (1-500 kPa) and fast response time (24 ms). Furthermore, the CLIG-based sensors provide a stable data source in the applications of human-motion monitoring, pressure array, and self-sensing soft robotic systems. High accuracy allows CLIG sensors to recognize more subtle signals, such as pulse, swallowing, gesture distinction of human, and movement status of soft robotics. Overall, this technology shows a promising strategy to fabricate high-performance sensors with high efficiency and low cost.

The demand of ultra-precision micro-machine tools is growing day by day due to exigent requirements of miniaturized components. High accuracy, good dimensional precision and smooth surface finish are the major characteristics of these ultra-precision machine tools. High-speed machining has been adopted to increase the productivity using high-speed spindles. However, machine tool vibration is a major issue in high-speed machining. Vibration significantly deteriorates the quality of micro-machining in terms of dimensional precision and surface finish. This article describes a design methodology of a closed type machine structure for vibration minimization of a high-speed micro-milling center. The rigid machine structure has provided high stiffness and the damping capability to the machine tool without utilizing vibration absorbers. The models of the machine structures have been generated and assembled in AutoCAD 3D. The performance of the integrated micro-milling machine tools was determined by finite element analysis. The best model has been selected and proposed for manufacturing. Additionally, simulation results were validated by comparing with experimental results. Eventually, after manufacturing and assembly, experiments have been performed and it was observed that the amplitude of vibration was approaching towards nanometer level throughout the working range of the high-speed spindle. The machine tool was capable to fabricate miniaturized components with smooth surface finish.

In this study, we proposed a Base S-type, long-period, fiber grating (Base S-type LPFG) coated with graphene oxide (GO) for sensing relative humidity based on the micro-electro-mechanical systems (MEMS) process and piezoelectric inkjet technology. The single mode optical fiber was etched to three different diameters (37, 42 and 60 μm) which were evaluated in the Base S-type LPFG. According to the experimental results, the diameter of 37 μm yielded the best sensitivity. Humidity sensor experiments showed that the Base S-type LPFG exhibited a high humidity sensitivity in a wide range from 20% RH to 80% RH. These experiments were repeated three times and the results showed that the average value of transmission loss sensitivity was −0.1824 dB/% RH and the average linear response had a correlation coefficient of 95.68%. The sensor exhibits good linearity, high stability, and reversibility in a wide working range. Therefore, the proposed graphene oxide-coated Base S-type LPFG humidity sensor has the potential for monitoring the relative humidity.

PurposeThe purpose of the experimental investigation was to optimize the process parameters of the fused deposition modeling (FDM) technique. The optimization of the process was performed to identify the relationship between the chosen factors and the tensile strength of acrylonitrile butadiene styrene (ABS) and carbon fiber polylactic acid (PLA) thermoplastic material, FDM printed specimens. The relationship was demonstrated by using the linear experimental model analysis, and a prediction expression was established. The developed prediction expression can be used for the prediction of tensile strength of selected thermoplastic materials at a 95% confidence level.Design/methodology/approachThe Taguchi L9 experimental methodology was used to plan the total number of experiments to be performed. The process parameters were chosen as three at three working levels. The working range of chosen factors was the printing speed (60, 80 and 100mm/min), 40%, 60% and 80% as the infill density and 0.1mm, 0.2mm and 0.3mm as the layer thickness. The fused deposition modeling process parameters were optimized to get the maximum tensile strength in FDM printed ABS and carbon fiber PLA thermoplastic material specimens.FindingsThe optimum condition was achieved by the process optimization, and the desired results were obtained. The maximum desirability was achieved as 0.98 (98%) for the factors, printing speed 100mm/min, infill density 60mm and layer thickness 0.3mm. The strength of the ABS specimen was predicted to be 23.83MPa. The observed strength value was 23.66MPa. The maximum desirability was obtained as 1 (100%) for the factors, printing speed 100mm/min, infill density 60mm and layer thickness 0.2mm. The strength of the carbon fiber PLA specimen was predicted to be 26.23MPa, and the obtained value was 26.49MPa.Research limitations/implicationsThe research shows the useful process parameters and their suitable working conditions to print the tensile specimens of the ABS and carbon fiber PLA thermoplastics by using the fused deposition modeling technique. The process was optimized to identify the most influential factor, and the desired optimum condition was achieved at which the maximum tensile strength was reported. The produced prediction expression can be used to predict the tensile strength of ABS and carbon fiber PLA filaments.Practical implicationsThe results obtained from the experimental investigation are useful to get an insight into the FDM process and working limits to print the parts by using the ABS and carbon fiber PLA material for various industrial and structural applications.Social implicationsThe results will be useful in choosing the suitable thermoplastic filament for the various prototyping and structural applications. The products that require freedom in design and are difficult to produce by most of the conventional techniques can be produced at low cost and in less time by the fused deposition modeling technique.Originality/valueThe process optimization shows the practical exposures to state an optimum working condition to print the ABS and carbon fiber PLA tensile specimens by using the FDM technique. The carbon fiber PLA shows better strength than ABS thermoplastic material.

The flexible strain sensor is of significant importance in wearable electronics, since it can help monitor the physical signals from the human body. Among various strain sensors, the foam-shaped ones have received widespread attention owing to their light weight and gas permeability. However, the working range of these sensors is still not large enough, and the sensitivity needs to be further improved. In this work, we develop a high-performance foam-shaped strain sensor composed of Ti3C2Tx MXene, multiwalled carbon nanotubes (MWCNTs), and thermoplastic polyurethane (TPU). MXene sheets are adsorbed on the surface of a composite foam of MWCNTs and TPU (referred to as TPU/MWCNTs foam), which is prefabricated by using a salt-templating method. The obtained TPU/MWCNTs@MXene foam works effectively as a lightweight, easily processable, and sensitive strain sensor. The TPU/MWCNTs@MXene device can deliver a wide working strain range of ∼100% and an outstanding sensitivity as high as 363 simultaneously, superior to the state-of-the-art foam-shaped strain sensors. Moreover, the composite foam shows an excellent gas permeability and suitable elastic modulus close to those of skin, indicating its being highly comfortable as a wearable sensor. Owing to these advantages, the sensor works effectively in detecting both subtle and large human movements, such as joint motion, finger motion, and vocal cord vibration. In addition, the sensor can be used for gesture recognition, demonstrating its perspective in human-machine interaction. Because of the high sensitivity, wide working range, gas permeability, and suitable modulus, our foam-shaped composite strain sensor may have great potential in the field of flexible and wearable electronics in the near future.

Wire Electrical Discharge Machining (WEDM) has been recently used to fabricate ultra-thin silicon wafers for applications in solar cells. However, the slicing of wafers induce thermal damage and deteriorate the surface of wafers, thereby requiring polishing to eliminate the damage. In order to reduce the polishing time, laser surface modification using nanosecond pulses is explored as a potential pre-treatment technique before polishing to reduce thermal damages incurred during the WEDM process. The process relies on the selection of appropriate parameters. Therefore, this work attempts at understanding the effect of various laser parameters on the surface to optimize the process for a nanosecond pulsed laser. Since the range of parameters to be used is entirely unknown, a numerical model is developed using the Finite Volume Method to arrive at a preliminary range of parameters to carry out the experimental work. The temperature profile obtained from the numerical model is then used to select the working range of laser power for the experiments. Experiments were carried out on WEDM sliced silicon wafers using the range of laser power obtained. Based on scanning electron microscope images, it was observed that the surface thermal damage depth reduced up to 50 % after laser processing. The thermal damage depth was observed to decrease with an increase in pulse repetition rate with a minimum at 50 kHz and increases thereafter. Besides, it was also observed that the residual stresses also reduced significantly at lower values of laser power and pulse repetition rate.

Significant efforts have been devoted to enhancing the sensitivity and working range of flexible pressure sensors to improve the precise measurement of subtle variations in pressure over a wide detection spectrum. However, achieving sensitivities exceeding 1000 kPa−1 while maintaining a pressure working range over 100 kPa is still challenging because of the limited intrinsic properties of soft matrix materials. Here, we report a magnetic field-induced porous elastomer with micropillar arrays (MPAs) as sensing materials and a well-patterned nickel fabric as an electrode. The developed sensor exhibits an ultrahigh sensitivity of 10,268 kPa−1 (0.6–170 kPa) with a minimum detection pressure of 0.25 Pa and a fast response time of 3 ms because of the unique structure of the MPAs and the textured morphology of the electrode. The porous elastomer provides an extended working range of up to 500 kPa with long-time durability. The sophisticated sensor system coupled with an integrated wireless recharging system comprising a flexible supercapacitor and inductive coils for transmission achieves excellent performance. Thus, a diverse range of practical applications requiring a low-to-high pressure range sensing can be developed. Our strategy, which combines a microstructured high-performance sensor device with a wireless recharging system, provides a basis for creating next-generation flexible electronics.

Accurate engine performance models are important for model-based performance evaluation of aero engine. The accuracy of the model often depends on engine component maps, so there is a need for a method that can accurately correct the component maps of the model over a wide range. In this paper, a new method for modifying component maps is proposed, this method combines the correction of the scaling factors with the solution process of the off-design working point, and uses the adjustment of the variable geometric parameters of the engine to change the position of the working line, in order to obtain more correction results and guarantee high accuracy in a wider range. The method is validated by taking the main fan of the Adaptive Cycle Engine (ACE), an ideal power unit for a new generation of multi-purpose and ultra-wide working range aircraft, as an example. The results show that the maximum error between the corrected component maps and the target maps is less than 1%. New possibility for more precise component maps can be realized in this paper.

Wind energy plays an increasingly important role in alleviating the shortage of fossil fuel energy because of the emerging promising technologies such as electromagnetic generators (EMGs), triboele...

Air leakage in underground coal mines presents a serious hazard for coal production and the safety of miners. Coating technology is commonly used as an efficient means for preventing air leakage. To address existing problems with high dust concentrations in large operations involving complex processes and the high cost of traditional coating technology, a novel coating technology that ensures intrinsic safety by utilizing water pressure and wind pressure was developed. This new coating technology was designed to suction and spray, and the technical parameters of its spray performance was also studied. The experimental tests and evaluation indicated the optimum working range is 0.3–0.7 MPa of wind pressure, 1.2–10.2 L/min of water quantity, and 1.0–3.5 m of spraying distance. Moreover, this novel coating technology was tested in the Dashuitou Coal Mine in Gansu Province of China. Compared with conventional counterparts, the proposed new technology is safe, efficient, and convenient to operate. During spraying, dust concentrations were kept at less than 10 mg/m3, and the average rebound ratio resilient rate of solid materials was below 13%. After spraying, the average leakage every 100 m was 4 m3/min, and the oxygen volume fraction in the adjacent goaf was approximately 4%, demonstrating excellent air leakage prevention.

The kinematic model of the working device of three-section boom excavator is established by using D-H method, the hydraulic cylinder of upper arm is segmented, and the envelope diagram of the three-section boom excavator is drawn with MATLAB by using superposition method. The simulation results show that the error between the simulation value and the sample value is within a reasonable range. The values of the main operating parameters and the corresponding change law when the hydraulic cylinder of upper boom is the shortest and the longest are analyzed, and the mathematical relationship between the length of the hydraulic cylinder of upper arm and the main operating parameters is fitted. The research results show that the main operating parameters above the horizontal plane increase with the increase of the length of the hydraulic cylinder of upper boom, while the main operating parameters below the horizontal plane decrease with the increase of the length of the hydraulic cylinder of upper boom. [ABSTRACT FROM AUTHOR]

Introduction of novel statistical technique for computing the interaction of lomefloxacin (LOME) and lanthanum (Ln) was the main purpose of this research. Moreover, using lanthanum as example of lanthanides for such interaction had not been exploited before. Screening of four factors affecting the interaction as metal volume, pH, temperature and reaction time was executed applying Plackett–Burman design where Pareto plots and ANOVA testing were used to pool off the insignificant factor. Accordingly, the imperative factors were optimized using Box–Behnken design after fine-tuning of the upper and lower levels values. 3-D surface plots and 2-D contour plots were chosen to evaluate the interaction between factors, followed by optimization plots to obtain the best blend of factors harmonized together and model confirmation was verified with three target points. Responses were measured as maximum absorbance; Y1 for technique (A) and maximum fluorescence intensity; Y2 for technique (B) using the resulted optimal conditions. Determination of LOME was applied with successful wide working range of (0.900–15.520, 0.070–1.552 µg/mL) for Y1 and Y2, respectively, with LOD and LOQ figured as 0.252, 0.763 µg/mL for Y1 and 0.0177, 0.0536 µg/mL for Y2. High degree of accuracy and precision was maintained in both pure and dosage forms findings. The techniques were found to be robust and adequate. Selectively of the models were proven by satisfactory % recovery calculations in interference tests. Statistical screening and optimization of the factors affecting the absorbance and fluorescence intensities of complexation of Lomefloxacin with lanthanum were achieved, followed by model confirmation and determinations in pure and dosage forms of the drug.

We propose a vertical linear motor (VLM) for semiconductor manufacturing equipment that compensates for the weight of the moving part by using the balance of magnetic and elastic forces. The developed VLM achieves zero stiffness with a constant upward force over a working range. The magnetic circuit of the VLM is designed to provide a linear negative stiffness over a ±2 mm stroke, with an upward force of 14 N at a 0 mm stroke. The negative stiffness is compensated for by the positive stiffness of elastic component-like springs. The upward force is then constant over the working range and corresponds to the weight of the moving part. The proposed VLM is designed to minimize the coupling effects of stiffness and gravity compensation forces by using magnetic flux saturation and magnetic flux path design. We investigate the effects of each design parameter on VLM operation through finite element analysis. Finally, the simulated forces in the proposed VLM are experimentally verified, indicating a linear negative stiffness of approximately −13.5 N/mm and a gravity compensation force of 14.9 N.

Wearable and highly sensitive pressure sensors are of great importance for robotics, health monitoring and biomedical applications. For simultaneously achieving high sensitivity within a broad working range, fast response time (within a few milliseconds), minimal hysteresis and excellent cycling stability are critical for high performance pressure sensors. However, it remains a major challenge. Herein, we report a conceptual micro-cliff design of a graphene sensor with a record high sensitivity of up to 72 568 kPa−1 in a broad working range of 0–255 kPa, which is one order of magnitude higher than the state-of-the-art reported sensitivity. In addition, the detection limit can be as low as 0.35 Pa and the fast response time is less than 5 ms. The sensor also has a minimal hysteresis and an outstanding cycling stability of 5000 cycles, all of which meet the requirements of an ideal pressure sensor. More interestingly, the micro-cliff graphene sensor is made by the fast and scalable flash reduction of graphene oxide using a single flashlight pulse within 150 ms and has been integrated into a wearable smart insole and an E-glove prototype for demonstration of health monitoring applications. This micro-cliff graphene pressure sensor achieves record-high sensitivity, which brings new possibilities in sensor research and promises broad applications.

Exploration of wearable strain sensors in diverse application scenarios is one global requirement for shaping the future of our intelligent community. However, state-of-the-art wearable devices still face challenges such as interference under humid conditions and chemical/mechanical fragility. Here, a facile and fluorine-free approach is introduced to realize a sensitive, robust and superhydrophobic strain sensor via the in situ formation of microcilia on the PDMS surface, followed by a two-step swelling process. The swelling process facilitates the penetration of carbon black nanoparticles into the PDMS matrix to render the conductive network suitable for strain sensing, while the decoration of silica nanoparticles along with the microcilia forms a hierarchical architecture for water repellency. The sensing performance was optimized, including the sensitivity (gauge factor of 354), working range (up to 250%), and long-term stability (>10 000 cycles). The superhydrophobic surface exhibits excellent resistance to mechanical abrasion, chemical corrosion, and high-speed water impact, etc. Demonstrations, such as body motion perception, wireless and underwater communications, Morse code generation, underwater jet impact, reveal the potential of the sensor as a robust platform for broad applications not only in air but also for underwater or under harsh condition uses.

The rapid development of human–machine interfaces and artificial intelligence is dependent on flexible and wearable soft devices such as sensors and energy storage systems. One of the key factors for these devices is the design of a flexible electrode with high sensitivity, fast response time, and a wide working range. Here, we report the fabrication of strain sensors and all-solid-state flexible supercapacitors using Co@N-CNT/MXenes as an electrode material. The manufactured sensor shows a high tensile range (strain up to 200%) and high stability. The resistance change caused by the fingers touching the sensor can be used to transmit the Morse code information. Flexible supercapacitors serving as power supply demonstrate excellent cycling stability (85 000 cycles) and coulombic efficiency (99.7%) for their high surface area and pseudocapacitance. A self-powered integrated system composed of the strain sensor and flexible supercapacitor is fabricated and operates stably in a wide strain sensing test range. Moreover, the flexible solar-charging self-powered integrated system could be attached to the human body for stable human motion detection. This study clearly shows that appropriate selection of a single functional material to enable it to be used in multi-functional sensors and supercapacitors can simplify the process and reduce the cost of manufacturing wearable devices.

Water sources are vulnerable to intentional and inadvertent human pollution with thousands of synthetic and geogenic trace contaminants, posing long-term effects on the aquatic ecosystem and human health. Thus, early and rapid detection of water pollutants followed by corrective and preventive actions can lead to the reduction of the overall polluting impact to safeguard public health. This study presents a generic sensing assay for the label-free detection of copper contaminants in environmental water samples using multilayered polyethylenimine (PEI) functionalized porous silicon Fabry-Pérot interferometers. The selective chelating activity of PEI thin-films was monitored in real-time by reflective interferometric Fourier transform spectroscopy (RIFTS) while assessing the improved optical responses. The optimized scaffold of two sequential PEI layers depicted a linear working range between 0.2 and 2 ppm while presenting a detection limit of 0.053 ppm (53 ppb). The specificity of the developed platform was cross-validated against various metallic pollutants and cations commonly found in water bodies (i.e., Cd2+, Pb2+, Cr3+, Fe3+, Mg2+, Ca2+, Zn2+, K+ and Al3+). Finally, as a proof of concept, the analytical performance of the porous interferometers for real-life scenarios was demonstrated in three water samples (tap, ground and irrigation), presenting sufficient adaptability to complex matrix analysis with recovery values of 85-106%. Overall, the developed sensing concept offers an efficient, rapid and label-free methodology that can be potentially adopted for routine on-site detection using a simple and portable device.

The effect of temperature on negatively charged nitrogen-vacancy (NV) centers in diamond is interesting owing to their high precision and high spatial resolution. In addition, this thermal effect has many applications, such as in magnetic imaging, materials science, and fundamental physics. Temperature sensitivity varies for different magnetic field directions. In this letter, a temperature working range of 260–500 K and sensitivity of 10 mK/√Hz were achieved. This could be a novel approach to study the thermal processes and thermodynamics of nanostructures.

Shaddock peel, a crop by-product mainly composed of cellulose, hemicellulose, lignin, and pectin, was developed as a flexible sensitive material for detecting environmental external pressure. Firstly, a natural carbon framework (C-SPF) with high conductivity was prepared using hydrothermal treatment followed by carbonization. Then, the PDMS elastomer was coated on the C-SPF instead of dense filling to convert the brittle C-SPF into elastic porous materials (M-SPF). Benefiting from the large deformation space of the porous framework and the stable interactions between PDMS and C-SPF, M-SPF exhibited ultrahigh coercibility (up to 99.0% strain) and high elasticity (99.4% height retention for 10 000 cycles at 50.0% strain). The M-SPF-based pressure sensor also exhibited a quick response (loading and unloading times were 20 ms and 30 ms), high sensitivity (63.4 kPa−1), wide working range (from 0 to 800 kPa), and stable stress-electric current response (10 000 cycles). These advantages open a door to a variety of applications, such as flexible wearable devices, which demonstrated human physiological signal monitoring. The low cost, simple design and portable use of piezoresistive sensors highlight the potential application of the crop by-product shaddock peel as a high-value material.

Summary Objectives The pharmaceutical industry and the National Regulatory Authorities (NRAs) are now focusing on the dissolution of multi-component drugs for quality control testing and predicting in vivo results to further consolidation of the biowaiver concept. The mixed formulation of Ciprofloxacin hydrochloride (CIP) and Metronidazole (MET) have been used as a model for simultaneous determination and obtaining in vitro dissolution profiles by using green analysis method namely (UV-CWT(Db4, a=490)). Material and methods The proposed method (UV-CWT(Db4, a=490)) includes UV detection combined with Continuous Wavelet Transform (CWT) with Daubechies family and the order of fourth at the scaling factor (a = 490) has been used and validated for analyzing and obtaining the dissolution profiles of the fixed-dose combination (CIP-MET). Results The proposed method (UV-CWT(Db4, a=490)) has been validated effectively in accordance with ICH rules, regarding linearity, specificity, rigor, and preciseness of the working range (3.0–16.0 μg/mL) for both (CIP) and (MET), respectively. As well as figures of merit were concluded. The dissolution profiles of CIP-MET tablets were acquired by the proposed (UV-CWT (Db4, a=490)) and HPLC reported methods were conveniently compared using the indicators f1 and f2 (“difference” and “similarity”) the results ensured that there were no statistically differences between the methods. In addition, the green assessment tool, namely analytical eco-scale, evaluated and compared the greenness of the suggested method (UV-CWT(Db4, a=490)) and HPLC reported one. Conclusion The suggested process (UV-CWT(Db4, a=490)) was considered as an excellent green, rapid, accurate, economical and minimum-steps method for simultaneously resolve and construct the dissolution curves of a fixed-dose combination drug (CIP-MET) in a short time and without the use of organic solvents, enabling significant labor and resource savings.

Intelligent flexible sensors that are comfortable to wear and have self-powered properties are primary candidates for next-generation wearable electronics. Nevertheless, most current flexible sensors cannot work independently, they have to rely on external power. Herein, we report a flexible sensing device that is able to reliably and stably monitor human motion with successive self-powering. The device consists of a supercapacitor as a power source and a strain sensor. An ionic hydrogel was used either as the electrolyte for the supercapacitor or as the functional element for the sensor. Thanks to the superior electromechanical and electrochemical properties of the hydrogel, when used as the electrolyte, the supercapacitor delivers over a wide voltage window (0–2.5 V), and exhibits superior energy density (81.46 mW h cm−2), and power density (2500 mW cm−2). The ionic hydrogel electrolyte also exhibits environmental durability and strain-resistance, demonstrating its reliability under deformation. Strain sensors based on such ionic organohydrogels operate over a wide working range (0–1000%), with high sensitivity (gauge factor = 6.04), and durability. Such a compact wearable sensing system presents potential applications in health monitoring by detecting motion precisely and rapidly. When machine learning is combined into a wearable sensing system, the intelligent device offers new prospects for tackling challenges in wearable electronics.

This work was aimed at the examination of the interaction of certain physicochemical properties on micellar systems constituting of a polymer (sodium alginate), two surfactants (CTAB and tween 80), and Algerian olive oil. Response surface modelling (RSM) was applied to study the combined effects of systems containing each type of surfactant. The monitoring of four independent parameters, i.e., the interfacial tension (Y1), the conductivity (Y2), the viscosity (Y3) and the turbidity (Y4) as responses for the experimental design model, allowed the determination of the performance of the established models. Based on statistical analyzes, the coefficients R2 and Q2 for the interfacial tension, the conductivity, the viscosity and the turbidity are: 0.998 and 0.805; 0.982 and 0.742; 0.976 and 0.734, and 0.985 and 0.723, respectively. The obtained results indicate that these models showed a good predictive power for an optimal system composed of CTAB, Tween 80, AlgNa, and olive oil. For the CTAB/AlgNa and CTAB/olive oil systems, interfacial tension values of 33.85 and 34.39 mN m-1, respectively, and maximum conductivity values of 4.126 and 4.064 mScm-1, respectively, were obtained. For viscous compounds consisting of AlgNa/Olive Oil and AlgNa/Tween 80, maximum viscosity values of 202.5 and 196.6 mPa s, respectively, were obtained. For the same systems as those for viscosity, turbidity values of 300 and 304 NTU, respectively, were obtained.

The implementation of precision engineering principles in the design of precision systems is fundamental to achieve high accuracy. Although these principles may be independent of the system working range, their implementation is not. The working range, the accuracy, and the load of the system limit, for instance, the selection of materials, the structural design, or the positioning system. This article analyzes the applicability of precision engineering design principles depending on the working range of the system in order to establish their scalability or lack of it in small, medium, and large range machines and instruments.

The question of the use of vortex flowmeters with different versions of the flow body (TO) under operating conditions on the technological lines of pulp and paper production is considered. It is shown that when using different TO in vortex flowmeters, an error occurs in the working range of speeds (flow rates). The observed error arises due to a change in the Strouhal number (Sh) and is associated with the measurement method. In this case, the Strouhal number begins to depend not only on the TO used as a vortex generator, but also on the flow velocity and the concentration of the fibrous suspension. As the main comparative factor for the investigated TOs, the force action on the sensitive element (flexible electrode) located inside the TO was taken. The study was carried out in several stages using numerical modeling and experimental design method. According to the results of a numerical study, the dependence of the Strouhal number (Sh) on the flow rate (V) and the concentration of the suspension (c) is presented. In a comparative analysis of the deviation of the Strouhal number from the average values, it was revealed that MOT No. 1 has a minimal effect on the concentration of the suspension in the working range of flow rates (± 0.5%). This circumstance makes it possible to verify and test flow meters with such maintenance in conventional pouring installations. The analysis of the maintenance with respect to the signal-to-noise ratio shows that the purest signal is generated by the cylindrical maintenance (maintenance No. 3), and maintenance No. 2 and No. 1 have noticeably large noise. The differences are explained by the absence on the surface of a cylindrical TO of extra protrusions, faces, which leads to a smoother flow of a suspension around its surface, as well as to a decrease in internal spurious noise.

As a rule, the width of a spectral line in atomic emission spectral analysis with arc sources is much smaller than the hardware function of the spectral device. Thus, the spectral line contour is determined by the hardware function of the device and can be approximated, e.g., by the Voigt function. However, when reference samples with a wide range of element concentrations are analyzed, there is a frequent problem of self-absorption that causes one to change the analytical line, which is not always possible. It is proposed to modify the Voigt function by adding a factor that describes self-absorption, by analogy with the Bouguer–Lambert law. The possibility of using the proposed function is evaluated during the analysis of reference samples of rocks, ores, and sandstones in a Grand-Potok spectral system with a MAES analyzer and BLPP-2000 photodetector arrays. The use of the proposed approximating function has provided an increase in the working range of the calibration curves of Cu 327.3954 nm, Cu 324.7532 nm, Pb 287.3311 nm, Ni 305.0818 nm, and Mo 313.2594 nm by 1–3 orders of magnitude.

With the continuous development of power automation and smart grids, online monitoring equipment has been utilized more widely for inspection of the state of high-voltage ac transmission lines. To ensure the stable and effective work of the monitoring device, the problem of power supply needs to be solved urgently. Although the inductive energy harvester penetrated through line has been extensively researched, the practical process has been greatly hindered caused by the core materials, which cannot simultaneously combine two advantages of both high permeability and high saturation. Based on the inherent contradiction of the inductive energy harvester, the structure of compound cores with different intrinsic properties is adopted. In addition, three optimization topologies for the structure are proposed. Theoretical analysis and experimental results show that the proposed structures and topologies have certain advantages over the conventional structure in terms of effective start-up sensitivity, saturation performance, and gained power. The proposed energy harvesters also broaden the effective working range by enduring the primary current fluctuation. The simulation and experimental results verify the correctness of the theoretical analysis and the validity of the topologies.

The use of buffers that mimic biological solutions is a foundation of biochemical and biophysical studies. However, buffering agents have both specific and nonspecific interactions with proteins. Buffer molecules can induce changes in conformational equilibria, dynamic behavior, and catalytic properties merely by their presence in solution. This effect is of concern because many of the standard experiments used to investigate protein structure and function involve changing solution conditions such as pH and/or temperature. In experiments in which pH is varied, it is common practice to switch buffering agents so that the pH is within the working range of the weak acid and conjugate base. If multiple buffers are used, it is not always possible to decouple buffer induced change from pH or temperature induced change. We have developed a series of mixed biological buffers for protein analysis that can be used across a broad pH range, are compatible with biologically relevant metal ions, and avoid complications that may arise from changing the small molecule composition of buffers when pH is used as an experimental variable.

The letter reports highly sensitive metal oxide (V2O5) based NanoElectromechanical Systems (NEMS) Pirani gauge for pressure monitoring of a packaged device. The absence of additional supplementary material in the sensing element increases the sensing area and enables the in-situ monitoring capability. Considering the feasibility of the idea, the design is simulated and verified with the experimental results of the fabricated device. The device shows a sensitivity of 5.76 % per decade-Pa in the working range from 4 Pa to $2.7\times 10^{3}$ Pa. The maximum average temperature of the sensing element is 48 °C at 4 Pa. It ensures corrosion-free operation and increases the lifetime of the device. The computed thermal response time of the device is ~500 ms at a power consumption of $285\mu \text{W}$ . [2020-0335]

The optimisation methodology was applied to design a specific geometry for a ring-shaped clip gauge as a quasi-static displacement measurement. The gauge was designed to maximise sensitivity under various types of constraints, including working range, strength, and installation. The analytical expressions of the ring gauge’s responses and constraints were derived to formulate an optimisation problem. The optimal solution was determined by an optimisation solver in the MathCAD Prime 4 program. The sensitivity of the objective function with respect to the parameters in the optimisation problem evaluated at the optimal solution was also determined. The sensitivity and linearity of the designed ring gauge is in the range of commercial gauges. The accuracy of the ring gauge was better than 0.1%, complying with ASTM standard E1820. Performance of the ring gauge, i.e. its linearity, hysteresis, and repeatability, was better than the DCB gauge reproduced from the standard. Applying the ring gauge to a tensile test with a cracked specimen yielded an accurate displacement measurement. Limitations of the analytical formulation are highlighted and recommendations for improving the formulation are discussed.

This manuscript reports, a novel, integrated on-chip sample-to-answer platform capable of detecting lead ions (Pb+2) directly in sediment samples. As sediment is one of the main sources of hazardous heavy metals in aquatic ecosystems, rapid and real-time detection of heavy metals in sediment is crucial in the field of environmental monitoring. Electrochemical sensors can provide rapid detection capability, but in-situ measurement of heavy metals with such sensors has been limited by complicated pretreatment steps. To overcome this drawback, an integrated system was developed consisting of a porous matrix for purification and extraction of Pb+2 onto a graphene oxide thin film that serves as an active sensing material. The integrated sensor with a 3D porous matrix was used as an in-situ platform to detect lead directly in complex sediment samples. The proposed electrochemical sensor has a detection limit of 4 ppb and a linear working range. The ability to directly detect lead in sediment samples with minimal pretreatment agents and time makes this system a promising solution for on-site monitoring of heavy metals in environmental samples. Although the current study focused on lead for platform validation, the proposed sensing platform can be further developed for the detection of a wide panel of toxic metals.