scholarly journals A Facile Design of Colourimetric Polyurethane Nanofibrous Sensor Containing Natural Indicator Dye for Detecting Ammonia Vapour

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6949
Author(s):  
Ayben Pakolpakçıl ◽  
Zbigniew Draczyński
Keyword(s):  
Colour Change ◽  
Organ Damage ◽  
Fast Response ◽  
Ammonia Vapour ◽  
Textile Sensors ◽  
Industrial Gases ◽  
The Fourier Transform ◽  
Indicator Dyes ◽  
Indicator Dye ◽  
Gas Leaks

Chemicals and industrial gases endanger both human health and the environment. The inhalation of colourless ammonia gas (NH3) can cause organ damage or even death in humans. Colourimetric materials are becoming more popular in the search for smart textiles for both fashion and specific occupational applications. Colourimetric textile sensors based on indicator dyes could be very useful for detecting strong gaseous conditions and monitoring gas leaks. In this study, black carrot extract (BCE) as a natural indicator dye and polyurethane (PU) polymer were used to develop a colourimetric sensor by electrospinning. The properties of the BCE/PU nanofibrous mats were characterized by the Fourier transform infrared spectrum (FTIR) and a scanning electron microscope (SEM). The BCE caused a change in the morphology of the PU nanofibrous mat. To evaluate the colour shift due to NH3 vapour, the BCE/PU nanofibrous mats were photographed by a camera, and software was used to obtain the quantitative colour data (CIE L*a*b). The BCE/PU nanofibrous exhibited a remarkable colour change from pink–red to green–blue under NH3 vapour conditions with a fast response time (≤30 s). These findings showed that colourimetric nanofibrous textile sensors could be a promising in situ material in protective clothing that changes colour when exposed to harmful gases.

scholarly journals Highly Sensitive E-Textile Strain Sensors Enhanced by Geometrical Treatment for Human Monitoring

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2383 ◽  
Author(s):  
Chi Cuong Vu ◽  
Jooyong Kim
Keyword(s):  
Form Factors ◽  
Human Movement ◽  
Fast Response ◽  
Strain Sensors ◽  
Electronic Textiles ◽  
Smart Textiles ◽  
Electronic Manufacturing ◽  
Starting Point ◽  
Textile Sensors ◽  
Manufacturing Techniques

Electronic textiles, also known as smart textiles or smart fabrics, are one of the best form factors that enable electronics to be embedded in them, presenting physical flexibility and sizes that cannot be achieved with other existing electronic manufacturing techniques. As part of smart textiles, e-sensors for human movement monitoring have attracted tremendous interest from researchers in recent years. Although there have been outstanding developments, smart e-textile sensors still present significant challenges in sensitivity, accuracy, durability, and manufacturing efficiency. This study proposes a two-step approach (from structure layers and shape) to actively enhance the performance of e-textile strain sensors and improve manufacturing ability for the industry. Indeed, the fabricated strain sensors based on the silver paste/single-walled carbon nanotube (SWCNT) layers and buffer cutting lines have fast response time, low hysteresis, and are six times more sensitive than SWCNT sensors alone. The e-textile sensors are integrated on a glove for monitoring the angle of finger motions. Interestingly, by attaching the sensor to the skin of the neck, the pharynx motions when speaking, coughing, and swallowing exhibited obvious and consistent signals. This research highlights the effect of the shapes and structures of e-textile strain sensors in the operation of a wearable e-textile system. This work also is intended as a starting point that will shape the standardization of strain fabric sensors in different applications.

scholarly journals Impact of impurities in bromocresol green indicator dye on spectrophotometric total alkalinity measurements

2020 ◽  
Author(s):  
Katharina Seelmann ◽  
Martha Gledhill ◽  
Steffen Aßmann ◽  
Arne Körtzinger
Keyword(s):  
High Performance ◽  
Total Alkalinity ◽  
Bromocresol Green ◽  
Ph Indicator ◽  
Purification Method ◽  
Common Technique ◽  
Drift Behavior ◽  
Indicator Dyes ◽  
Indicator Dye

Abstract. Due to its accurate and precise character, the spectrophotometric pH detection is a common technique applied in measurement methods for carbonate system parameters. However, impurities in the used pH indicator dyes can influence the measurements quality. The work described here focuses on influences from impurities in the pH indicator dye bromocresol green (BCG) on spectrophotometric seawater total alkalinity (AT) measurements. First, a high-performance liquid chromatography (HPLC) purification method for BCG was developed. A subsequent analysis of BCG dye from four different vendors with this method revealed different types and quantities of impurities. After successful purification, AT measurements with purified and unpurified BCG were carried out using the novel autonomous analyzer CONTROS HydroFIA® TA. Long-term measurements in the laboratory revealed a direct influence of impurity types and quantities on the drift behavior of the analyzer. The purer the BCG, the smaller was the drift increment per measurement. Furthermore, we could show that a certain impurity in some indicator dyes changed the drift pattern from linear to non-linear, which can impair the AT measurements during a long-term deployment of the system. Laboratory performance characterization experiments revealed no improvement of the measurement quality (precision and accuracy) by using purified BCG as long as the impurities of the unpurified dye do not exceed a quantity of 2 % (relationship of peak areas in the chromatogram). However, BCG with impurity quantities higher than 6 % provided AT values, which failed fundamental quality requirements. Concluding, to gain optimal AT measurements, an indicator purification is not necessarily required as long as the purchased dye has a purity level of at least 98 %.

Automatic Method for the Determination of Calcium in the Presence of Magnesium and Phosphate Ions

1966 ◽  
Vol 12 (7) ◽  
pp. 418-427 ◽  
Author(s):  
Preston Smith ◽  
Caroline H Kurtzman ◽  
Mary E Ambrose
Keyword(s):  
Citric Acid ◽  
Automatic Method ◽  
Magnesium Ions ◽  
Phosphate Ions ◽  
Automated Method ◽  
Manual Analysis ◽  
Accuracy And Precision ◽  
Indicator Dyes ◽  
Indicator Dye

Abstract A direct spectrophotometric method for manual analysis of calcium using the indicator dye Eriochrome Blue S. E. was selected for automation. Most indicator dyes used have been somewhat unstable in solutions sufficiently alkaline to minimize the interference of magnesium. Eriochrome Blue S. E., when kept in an ice bath in the absence of light, permitted the use of sufficient alkali to remove interfering magnesium ions. Magnesium did not interfere in concentrations up to 12 mg./100 ml. when added to standards. The addition of 0.5% (w/v) citric acid removed interference of phosphate in concentrations up to 300 mg./100 ml. The automated method has the advantage of speed, yet retains the accuracy and precision of the conventional methods used for determining calcium.

scholarly journals Single-Layer Pressure Textile Sensors with Woven Conductive Yarn Circuit

2020 ◽  
Vol 10 (8) ◽  
pp. 2877 ◽  
Author(s):  
Gaeul Kim ◽  
Chi Cuong Vu ◽  
Jooyong Kim
Keyword(s):  
Pressure Sensor ◽  
Pressure Sensors ◽  
Single Layer ◽  
Fast Response ◽  
Resistance Change ◽  
Load Pressure ◽  
Pressure Sensitive ◽  
High Durability ◽  
Textile Sensors ◽  
Conductive Fibers

Today, e-textiles have become a fundamental trend in wearable devices. Fabric pressure sensors, as a part of e-textiles, have also received much interest from many researchers all over the world. However, most of the pressure sensors are made of electronic fibers and composed of many layers, including an intermediate layer for sensing the pressure. This paper proposes the model of a single layer pressure sensor with electrodes and conductive fibers intertwined. The plan dimensions of the fabricated sensors are 14 x 14 mm, and the thickness is 0.4 mm. The whole area of the sensor is the pressure-sensitive point. As expected, results demonstrate an electrical resistance change from 283 Ω at the unload pressure to 158 Ω at the load pressure. Besides, sensors have a fast response time (50 ms) and small hysteresis (5.5%). The hysteresis will increase according to the pressure and loading distance, but the change of sensor loading distance is very small. Moreover, the single-layer pressure sensors also show high durability under many working cycles (20,000 cycles) or washing times (50 times). The single-layer pressure sensor is very thin and more flexible than the multi-layer pressure sensor. The structure of this sensor is also expected to bring great benefits to wearable technology in the future.

scholarly journals Impact of impurities in bromocresol green indicator dye on spectrophotometric total alkalinity measurements

Ocean Science ◽  
2020 ◽  
Vol 16 (2) ◽  
pp. 535-544
Author(s):  
Katharina Seelmann ◽  
Martha Gledhill ◽  
Steffen Aßmann ◽  
Arne Körtzinger
Keyword(s):  
High Performance ◽  
Total Alkalinity ◽  
Bromocresol Green ◽  
Ph Indicator ◽  
Purification Method ◽  
Common Technique ◽  
Drift Behavior ◽  
Indicator Dyes ◽  
Indicator Dye

Abstract. Due to its accurate and precise character, spectrophotometric pH detection is a common technique applied in measurement methods for carbonate system parameters. However, impurities in the used pH indicator dyes can influence the measurements quality. During our work described here, we focused on impacts of impurities in the pH indicator dye bromocresol green (BCG) on spectrophotometric seawater total alkalinity (AT) measurements. In order to evaluate the extent of such influences, purified BCG served as a reference. First, a high-performance liquid chromatography (HPLC) purification method for BCG was developed as such a method did not exist at the time of this study. An analysis of BCG dye from four different vendors with this method revealed different types and quantities of impurities. After successful purification, AT measurements with purified and unpurified BCG were carried out using the novel autonomous analyzer CONTROS HydroFIA® TA. Long-term measurements in the laboratory revealed a direct influence of impurity types and quantities on the drift behavior of the analyzer. The purer the BCG, the smaller was the AT increase per measurement. The observed drift is generally caused by deposits in the optical pathway mainly generated by the impurities. However, the analyzers drift behavior could not be fully overcome. Furthermore, we could show that a certain impurity type in some indicator dyes changed the drift pattern from linear to nonlinear, which can impair long-term deployments of the system. Consequently, such indicators are impractical for these applications. Laboratory performance characterization experiments revealed no improvement of the measurement quality (precision and bias) by using purified BCG as long as the impurities of the unpurified dye do not exceed a quantity of 2 % (relationship of peak areas in the chromatogram). However, BCG with impurity quantities higher than 6 % provided AT values which failed fundamental quality requirements. In conclusion, to gain optimal AT measurements especially during long-term deployments, an indicator purification is not necessarily required as long as the purchased dye has a purity level of at least 98 % and is free of the named impurity type. Consequently, high-quality AT measurements do not require pure but the purest BCG that is purchasable.

IMAGING CALCIUM WAVES IN EGGS AND EMBRYOS

1993 ◽  
Vol 184 (1) ◽  
pp. 213-219 ◽  
Author(s):  
I Gillot ◽  
M Whitaker
Keyword(s):  
Latent Period ◽  
Calcium Concentration ◽  
Calcium Influx ◽  
Embryonic Cell ◽  
Calcium Wave ◽  
Free Calcium ◽  
Calcium Indicator ◽  
Free Calcium Concentration ◽  
Indicator Dyes ◽  
Indicator Dye

Sea urchin eggs and those of most other deuterostomes are activated at fertilization by an increase in cytoplasmic free calcium concentration ([Ca2+]i) that triggers the onset of the embryonic cell division cycles. We can image the calcium wave using fluorescent calcium indicator dyes and confocal microscopy. There are two components to the [Ca2+]i increase at fertilization. The first is due to a rapid calcium influx caused by a calcium action potential; this leads to a small increase in [Ca2+]i just beneath the plasma membrane with spherical symmetry. After a latent period of some 15 s, there is a second large and rapid increase in [Ca2+]i localized to the region of sperm-egg contact: during the latent period [Ca2+]i does not change but within 1 s of the end of the latent period [Ca2+]i reaches 2 micromolar. The calcium wave then spreads across the egg with a velocity of 5 micrometre s-1. Behind the advancing wavefront, the calcium concentration is uniformly high, even within the egg nucleus, though there are no indications that intranuclear calcium concentration differs from [Ca2+]i. [Ca2+]i falls uniformly towards resting levels over the next 500 s. In cases where there is an apparent inhomogeneity in [Ca2+]i in either the cortex or the nucleus, we find that the calcium indicator dye is inhomogeneously distributed. This appears to be due to uptake of the indicator dye (Fluo-3), probably into mitochondria. The artefact can be avoided by using a dextran-conjugated dye.

scholarly journals The Oxygen Analyser: Applications and Limitations – An Analysis of 2000 Incident Reports

1993 ◽  
Vol 21 (5) ◽  
pp. 570-574 ◽  
Author(s):  
L. Barker ◽  
R. K. Webb ◽  
W. B. Runciman ◽  
J. H. Van Der Walt
Keyword(s):  
Anaesthetic Machine ◽  
Organ Damage ◽  
Improper Use ◽  
Total Failure ◽  
The Common ◽  
Incident Reports ◽  
Oxygen Analyser ◽  
Gas Leaks ◽  
Hypoxic Mixtures

The first 2000 incidents reported to the Australian Incident Monitoring Study were analysed with respect to the role of the oxygen analyser; 27 (1%) were first detected by the oxygen analyser. All of these were amongst the 1256 incidents which occurred in association with general anaesthesia, of which 48% were “human detected” and 52% “monitor detected”. The oxygen analyser was ranked 7th and detected 4% of these monitor detected incidents. This figure would have been much higher had the oxygen analyser been correctly used on more occasions. The oxygen analyser detected 10 ventilator-driving-gas leaks into the circuit, 6 hypoxic mixtures due to rotameter settings, 3 inappropriate nitrous oxide concentrations, 2 disconnections and 1 leak at the common gas outlet, and 2 partial and 1 total failure of ventilation. In a theoretical analysis of these 1256 incidents it was considered that the oxygen analyser, used on its own, would have detected 114 (9%), had they been allowed to evolve (3% before any potential for organ damage). In 4 incidents an oxygen analyser gave faulty readings, in 3 caused a leak and in one a total circuit obstruction; 5 incidents were not detected because the alarm had been disabled. Despite the advent of piped gas supplies, failure of gas delivery or delivery of a “wrong” gas mixture still occurs surprisingly frequently in current anaesthetic practice; hypoxic mixtures were supplied on 16 occasions, other “wrong” mixtures on 23 and the oxygen supply failed on 7 occasions. Failure to use and improper use of the oxygen analyser is also surprisingly common; this is mainly due to a rule-based error encouraged by the poor design of the high alarm. It is highly recommended that a suitable, correctly sited, calibrated, tested oxygen analyser be used from before pre-oxygenation until the patient is no longer breathing gas from the anaesthetic machine or circuit.

scholarly journals On Methane Leaks from Pipelines in Bryan and College Station, Texas, USA

2016 ◽  
Vol 10 (1) ◽  
pp. 56-62 ◽  
Author(s):  
Kristen Koch ◽  
Shelby Thomas ◽  
Elora Arana ◽  
Geoff Roest ◽  
Gunnar W. Schade
Keyword(s):  
Natural Gas ◽  
Distribution System ◽  
Urban Areas ◽  
Fossil Fuel ◽  
Fast Response ◽  
Metropolitan Region ◽  
Pipeline System ◽  
Domestic Ruminants ◽  
The Us ◽  
Gas Leaks

Methane is the second most important anthropogenically emitted greenhouse gas after carbon dioxide. Anthropogenic methane sources in the US are dominated by emissions from domestic ruminants and from fossil fuel exploration, storage and transmission. The fossil fuel source is primarily due to natural gas leaks along the production to distribution chain, and pipeline leaks in urban areas have been identified as a significant contributor. In this study, we evaluated possible leaks in three neighborhoods of a midsize Texas metropolitan region surrounding Texas A&M University through mobile measurements using a fast response, high precision methane analyzer. Neighborhoods were selected by age and land use, and each predetermined driving route was evaluated three times. Methane spikes exceeding 2.5 ppm were identified as leaks, and approximately one leak per mile of urban road was discovered. The largest leaks were found around the Texas A&M natural gas plant and in the oldest neighborhood to its north, while fewer leaks were found in a slightly younger neighborhood. No leaks were found in the youngest, less than 20-year old neighborhood suggesting that pipeline system age is a strong determinant of current and future leaks from the natural gas distribution system.

scholarly journals Use of fluo-3 to measure cytosolic Ca2+ in platelets and neutrophils. Loading cells with the dye, calibration of traces, measurements in the presence of plasma, and buffering of cytosolic Ca2+

1990 ◽  
Vol 269 (2) ◽  
pp. 513-519 ◽  
Author(s):  
J E Merritt ◽  
S A McCarthy ◽  
M P A Davies ◽  
K E Moores
Keyword(s):  
Acetic Acid ◽  
Cell Types ◽  
Excitation Wavelength ◽  
Temperature Dependent ◽  
Fura 2 ◽  
Indicator Dyes ◽  
Indicator Dye

A description is given of the methodology, and problems encountered, for the use of a new fluorescent Ca2(+)-indicator dye, fluo-3, in neutrophils and platelets. The higher Kd and longer excitation wavelength of fluo-3 can have significant advantages over fura-2. Although neutrophils and platelets are used as examples, these observations will be applicable to other cell types. The Kd of fluo-3 for binding Ca2+ at 37 degrees C was measured and found to be 864 nM; the previously published value was 400 nM at 22 degrees C. The Kd of fluo-3, like that of fura-2, is therefore very temperature-dependent. Protocols for loading cells, and preventing leakage of fluo-3, are described; probenecid, known to inhibit fura-2 leakage from cells, was found to be essential to get good fluo-3 signals from platelets. Calibration of fluo-3 fluorescence signals to [Ca2+] and methods for obtaining maximum and minimum fluorescence signals are described; these methods differ from those used with fura-2. Agonist-stimulated responses of fluo-3-loaded neutrophils and platelets are shown, and the calculated cytosolic [Ca2+] is comparable with that previously obtained with fura-2. Responses of cells in the presence of plasma are also shown; such measurements, unobtainable with quin2, fura-2 or indo-1, are possible with fluo-3, owing to its longer excitation wavelengths. Co-loading of cells with bis-(o-aminophenoxy)ethane-NNN′N′-tetra-acetic acid and fluo-3 is included as an example of how cytosolic [Ca2+] can be buffered and manipulated. Many of these observations will be of value when using fluo-3 (or other Ca2(+)-indicator dyes) in most cell types.

scholarly journals A Facile Approach of Fabricating Electrically Conductive Knitted Fabrics Using Graphene Oxide and Textile-Based Waste Material

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 3003
Author(s):  
Md Abdullah Al Faruque ◽  
Alper Kiziltas ◽  
Deborah Mielewski ◽  
Maryam Naebe
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Colour Change ◽  
Reduction Process ◽  
Composite Fibre ◽  
Knitted Fabrics ◽  
Electrically Conductive ◽  
Coated Fabrics ◽  
The Fourier Transform ◽  
Application Fields

This research investigated a feasible approach to fabricating electrically conductive knitted fabrics using previously wet-spun wool/polyacrylonitrile (PAN) composite fibre. In the production of the composite fibre, waste wool fibres and PAN were used, whereby both the control PAN (100% PAN) and wool/PAN composite fibres (25% wool) were knitted into fabrics. The knitted fabrics were coated with graphene oxide (GO) using the brushing and drying technique and then chemically reduced using hydrazine to introduce the electrical conductivity. The morphological study showed the presence of GO sheets wrinkles on the coated fabrics and their absence on reduced fabrics, which supports successful coating and a reduction of GO. This was further confirmed by the colour change properties of the fabrics. The colour strength (K/S) of the reduced control PAN and wool/PAN fabrics increased by ~410% and ~270%, and the lightness (L*) decreased ~65% and ~71%, respectively, compared to their pristine fabrics. The Fourier transform infrared spectroscopy showed the presence and absence of the GO functional groups along with the PAN and amide groups in the GO-coated and reduced fabrics. Similarly, the X-ray diffraction analysis exhibited a typical 2θ peak at 10⁰ that represents the existence of GO, which was demolished after the reduction process. Moreover, the wool/PAN/reduced GO knitted fabrics showed higher electrical conductivity (~1.67 S/cm) compared to the control PAN/reduced GO knitted fabrics (~0.35 S/cm). This study shows the potential of fabricating electrically conductive fabrics using waste wool fibres and graphene that can be used in different application fields.

Sign in / Sign up

Export Citation Format

Share Document