Fabrication of a Low-Coercivity, Large-Magnetoresistance PVA/Fe/Co/Ni Nanofiber Composite Using an Electrospinning Technique and Its Characterization

2020 ◽  
Vol 20 (6) ◽  
pp. 3504-3511 ◽  
Author(s):  
A. Robertsam ◽  
N. Victor Jaya
Keyword(s):  
Low Cost ◽  
Cobalt Nitrate ◽  
Electrospinning Process ◽  
Poly Vinyl Alcohol ◽  
Ferric Nitrate ◽  
Electrospinning Technique ◽  
Nanofiber Composite ◽  
Sensing Applications ◽  
Heat Treated ◽  
Highly Sensitive

A nanofiber composite is a unique engineered material, which can impart new physical, chemical, and electrical properties. Among existing polymer composites, the metallic nanofiber composite has a significant role in biomedical applications. In this study, a metallic nanofiber composite was fabricated using poly vinyl alcohol [PVA-(C2H4O)n] reinforced with ferric nitrate [Fe(NO3)3·9H2O], cobalt nitrate [Co(NO3)2·6H2O], and nickel acetate [C4H6NiO4·4H2O] using a low-cost electrospinning process. The process parameters were optimized for fabricating uniform, bead-free, and substratefree fibers. The morphological features of the composite were evaluated using a scanning electron microscope (SEM). Hysteresis of the heat-treated composite was studied using a vibrating sample magnetometer (VSM). This study showed that the composite behaved as a ferromagnetic (intermediate) material with coercivity in the range 318–671 G for different wt.% of nickel. Pellets (8-mm diameter and 250-μm thickness) of this composite changed the resistance by 18% when dispensed in a magnetic field of 1200 G at an ambient temperature. Based on a thermogravimetric analysis, the thermal stability and magnetoresistance property showed that the fabricated composite was suitable for developing a highly sensitive magnetic sensor, which could be used in bio-sensing applications.

scholarly journals Trimodal Waveguide Demonstration and Its Implementation as a High Order Mode Interferometer for Sensing Application

Sensors ◽  
2019 ◽  
Vol 19 (12) ◽  
pp. 2821 ◽  
Author(s):  
Jhonattan C. Ramirez ◽  
Lucas H. Gabrielli ◽  
Laura M. Lechuga ◽  
Hugo E. Hernandez-Figueroa
Keyword(s):  
Free Spectral Range ◽  
Point Of Care ◽  
Low Cost ◽  
High Order Mode ◽  
Sio2 Substrate ◽  
Polymer Waveguide ◽  
Sensing Applications ◽  
Highly Sensitive ◽  
Different Types ◽  
Mode Order

This work implements and demonstrates an interferometric transducer based on a trimodal optical waveguide concept. The readout signal is generated from the interference between the fundamental and second-order modes propagating on a straight polymer waveguide. Intuitively, the higher the mode order, the larger the fraction of power (evanescent field) propagating outside the waveguide core, hence the higher the sensitivity that can be achieved when interfering against the strongly confined fundamental mode. The device is fabricated using the polymer SU-8 over a SiO2 substrate and shows a free spectral range of 20.2 nm and signal visibility of 5.7 dB, reaching a sensitivity to temperature variations of 0.0586 dB/ ∘ C. The results indicate that the proposed interferometer is a promising candidate for highly sensitive, compact and low-cost photonic transducer for implementation in different types of sensing applications, among these, point-of-care.

scholarly journals Sensing of Oxygen Partial Pressure in Air with ZnO Nanoparticles

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 562
Author(s):  
Xin Chang ◽  
Shunpu Li ◽  
Daping Chu
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Low Cost ◽  
Electrical Conductance ◽  
Zno Nanoparticle ◽  
Sensing Applications ◽  
Highly Sensitive ◽  
Sensitive Sensor ◽  
Micrometer Scale ◽  
Higher Sensitivity

The demand for sensors in response to oxygen partial pressure in air is increasingly high in recent years and small-size sensors on a micrometer scale and even a nanometer scale are particularly desirable. In this paper, the sensing of oxygen partial pressure in air was realized by a solution-processed ZnO nanoparticle (NP). Thin-film ZnO NP was prepared by spin-coating and a highly sensitive sensor was then fabricated. The oxygen sensing performance was characterized in air and compared with that in nitrogen, which showed an increase in electrical conductance by more than 100 times as a result of decreasing oxygen partial pressure from 103 mBar to 10−5 mBar. Moreover, higher sensitivity was achieved by increasing the annealing temperature and the effect of thermal annealing was also investigated. Furthermore, ZnO NP lines with 7 μm in width were successfully patterned with low cost by a mould-guided drying technique from ZnO NP dispersion, which makes ZnO NP extremely promising for miniaturized and integrated sensing applications.

Preparation and Characterization of PVA/Boron Polymer Produced by an Electrospinning Technique.

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
I. Uslu ◽  
H. Daştan ◽  
A. Altaş ◽  
A. Yayli ◽  
O. Atakol ◽  
...  
Keyword(s):  
Boron Oxide ◽  
Vinyl Alcohol ◽  
Electrospinning Process ◽  
Poly Vinyl Alcohol ◽  
Boron Addition ◽  
Electrospinning Technique ◽  
Boron Doped ◽  
Ft Ir ◽  
Pva Solutions

Abstract In this study, poly(vinyl alcohol) were cross-linked with boron in varying concentrations and blend fibers were obtained with diameters ranging from 0.3 μ to 4.0 μm with the use of electrospinning process. The resulting product was characterized by SEM, DSC, and FT-IR techniques. There is no beading tendency in either boron doped or undoped fibers. When the amount of boric acid in PVA solutions was increased the conductivity of the polymer decreased. The data indicated the existence of boron oxide in the polymeric structure and the formation of B-O-C bond. SEM micrographs reveal that higher viscosity favors the formation of thicker fibers. Boron addition seems to disturb the easy detachment of the fibers from the tip of the Taylor Cone

Physical Characterization of Titanium Dioxide Nanofiber Prepared by Electrospinning Method

2016 ◽  
Vol 1133 ◽  
pp. 386-390
Author(s):  
N.A.M. Nor ◽  
Juhana Jaafar ◽  
Mukhlis A. Rahman ◽  
M.H.D. Othman ◽  
Norhaniza Yusof ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Precursor Solution ◽  
Rutile Phase ◽  
Electrospinning Process ◽  
Titanium Tetraisopropoxide ◽  
X Ray Diffraction ◽  
Electrospinning Technique ◽  
Heat Treated ◽  
Electrospinning Method ◽  
High Voltage Supply

Titanium dioxide nanofibers with diameter ranging to several nanometers were synthesized via electrospinning technique. The precursor solution was prepared by mixing the polyvinylpyrrolidone, PVP (MW~1,300,000) in ethanol, meanwhile titanium tetraisopropoxide, TTIP in acetic acid was slowly added into the solution under a vigorous stirring. The precursor solutions were then used in the electrospinning process under high voltage supply. As-spun nanofibers were heat-treated under different temperature 400°C and 500°C. The TiO2 nanofibers were characterized by using scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) and X-ray diffraction (XRD). The results indicated that the heat treated TiO2 nanofibers consist of anatase and rutile phases. As the calcination temperature increased (400-500°C), the anatase phases are greater than rutile phase and specific surface area are decreases while the calcination process influenced the nanofibers diameter.

scholarly journals Aerogels for Biomedical, Energy and Sensing Applications

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 264
Author(s):  
Muhammad Tayyab Noman ◽  
Nesrine Amor ◽  
Azam Ali ◽  
Stanislav Petrik ◽  
Radek Coufal ◽  
...  
Keyword(s):  
High Performance ◽  
Structural Characteristics ◽  
Low Cost ◽  
Three Dimensional ◽  
Strain Sensors ◽  
High Porosity ◽  
Energy Materials ◽  
Sensing Applications ◽  
Highly Sensitive ◽  
Solid State Structures

The term aerogel is used for unique solid-state structures composed of three-dimensional (3D) interconnected networks filled with a huge amount of air. These air-filled pores enhance the physicochemical properties and the structural characteristics in macroscale as well as integrate typical characteristics of aerogels, e.g., low density, high porosity and some specific properties of their constituents. These characteristics equip aerogels for highly sensitive and highly selective sensing and energy materials, e.g., biosensors, gas sensors, pressure and strain sensors, supercapacitors, catalysts and ion batteries, etc. In recent years, considerable research efforts are devoted towards the applications of aerogels and promising results have been achieved and reported. In this thematic issue, ground-breaking and recent advances in the field of biomedical, energy and sensing are presented and discussed in detail. In addition, some other perspectives and recent challenges for the synthesis of high performance and low-cost aerogels and their applications are also summarized.

scholarly journals Influence of Modified Cationic Starch in a Mixed Poly(Vinyl Alcohol)/Cationic Starch Solution on the Electrospinning Process and Web Structure

2020 ◽  
Vol 20 (1) ◽  
pp. 69-72
Author(s):  
Jurgita Šateikė ◽  
Rimvydas Milašius
Keyword(s):  
Vinyl Alcohol ◽  
Total Concentration ◽  
Negative Influence ◽  
Electrospinning Process ◽  
Poly Vinyl Alcohol ◽  
Mixed Solution ◽  
Cationic Starch ◽  
Electrospinning Technique ◽  
Structure And Morphology ◽  
Web Structure

AbstractNanofibers were electrospun from bicomponent poly(vinyl alcohol) (PVA) and modified cationic starch (CS) mixed solution PVA/CS with different mass ratios (75/25, 50/50 and 35/65) at a total concentration of 12 wt% for all polymer compositions. For comparison, pure PVA solution was used. Electrospinning technique Nanospider (Elmarco, Czech Republic) with a rotating electrode with tines was used to obtain nanofibrous web. The influence of prepared polymer solution compositions on the structure and morphology of nanofibers and webs were investigated. Analyzing the structure and morphology of the formed nanofiber webs, it was noticed that the fineness nanofibers were formed from the PVA/CS solution with a mass ratio of 50/50. This ratio of solution also lets us to obtain the nanofibrous web with less sticked nanofibers on spunbond. The increase in the CS ratio by more than 50/50 had a negative influence on the diameter of nanofibers and the structure of nanofibrous web.

Computer simulation study about the dependence of amorphous silicon photonic waveguides efficiency on the material quality

2020 ◽  
Vol 90 (3) ◽  
pp. 30502
Author(s):  
Alessandro Fantoni ◽  
João Costa ◽  
Paulo Lourenço ◽  
Manuela Vieira
Keyword(s):  
Amorphous Silicon ◽  
High Throughput Screening ◽  
Simulation Analysis ◽  
Low Cost ◽  
Deposition Process ◽  
Large Area ◽  
Sidewall Roughness ◽  
Sensing Applications ◽  
Fabrication Defects ◽  
The Impact

Amorphous silicon PECVD photonic integrated devices are promising candidates for low cost sensing applications. This manuscript reports a simulation analysis about the impact on the overall efficiency caused by the lithography imperfections in the deposition process. The tolerance to the fabrication defects of a photonic sensor based on surface plasmonic resonance is analysed. The simulations are performed with FDTD and BPM algorithms. The device is a plasmonic interferometer composed by an a-Si:H waveguide covered by a thin gold layer. The sensing analysis is performed by equally splitting the input light into two arms, allowing the sensor to be calibrated by its reference arm. Two different 1 × 2 power splitter configurations are presented: a directional coupler and a multimode interference splitter. The waveguide sidewall roughness is considered as the major negative effect caused by deposition imperfections. The simulation results show that plasmonic effects can be excited in the interferometric waveguide structure, allowing a sensing device with enough sensitivity to support the functioning of a bio sensor for high throughput screening. In addition, the good tolerance to the waveguide wall roughness, points out the PECVD deposition technique as reliable method for the overall sensor system to be produced in a low-cost system. The large area deposition of photonics structures, allowed by the PECVD method, can be explored to design a multiplexed system for analysis of multiple biomarkers to further increase the tolerance to fabrication defects.

scholarly journals A rapid, accurate, scalable, and portable testing system for COVID-19 diagnosis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guanhua Xun ◽  
Stephan Thomas Lane ◽  
Vassily Andrew Petrov ◽  
Brandon Elliott Pepa ◽  
Huimin Zhao
Keyword(s):  
Limit Of Detection ◽  
Low Cost ◽  
High Volume ◽  
N Gene ◽  
Testing System ◽  
Target Sequence ◽  
One Pot ◽  
Sequence Detection ◽  
Highly Sensitive ◽  
Speed Accuracy

AbstractThe need for rapid, accurate, and scalable testing systems for COVID-19 diagnosis is clear and urgent. Here, we report a rapid Scalable and Portable Testing (SPOT) system consisting of a rapid, highly sensitive, and accurate assay and a battery-powered portable device for COVID-19 diagnosis. The SPOT assay comprises a one-pot reverse transcriptase-loop-mediated isothermal amplification (RT-LAMP) followed by PfAgo-based target sequence detection. It is capable of detecting the N gene and E gene in a multiplexed reaction with the limit of detection (LoD) of 0.44 copies/μL and 1.09 copies/μL, respectively, in SARS-CoV-2 virus-spiked saliva samples within 30 min. Moreover, the SPOT system is used to analyze 104 clinical saliva samples and identified 28/30 (93.3% sensitivity) SARS-CoV-2 positive samples (100% sensitivity if LoD is considered) and 73/74 (98.6% specificity) SARS-CoV-2 negative samples. This combination of speed, accuracy, sensitivity, and portability will enable high-volume, low-cost access to areas in need of urgent COVID-19 testing capabilities.

scholarly journals Immobilization of Pseudomonas aeruginosa static biomass on eggshell powder for on-line preconcentration and determination of Cr (VI)

2020 ◽  
Vol 18 (1) ◽  
pp. 303-313 ◽  
Author(s):  
Aamir Rasheed ◽  
Tahseen Ghous ◽  
Sumaira Mumtaz ◽  
Muhammad Nadeem Zafar ◽  
Kalsoom Akhter ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Low Cost ◽  
Colorimetric Detection ◽  
Time Flow ◽  
Highly Sensitive ◽  
Glass Column ◽  
On Line ◽  
Preconcentration Time ◽  
Ultra Trace

AbstractIn the present work, a novel continuous flow system (CFS) is developed for the preconcentration and determination of Cr (VI) using Pseudomonas aeruginosa static biomass immobilized onto an effective and low-cost solid support of powdered eggshells. A mini glass column packed with the immobilized biosorbent is incorporated in a CFS for the preconcentration and determination of Cr (VI) from aqueous solutions. The method is based on preconcentration, washing and elution steps followed by colorimetric detection with 1,5-diphenyl carbazide in sulphuric acid. The effects of several variables such as pH, retention time, flow rate, eluent concentration and loaded volume are studied. Under optimal conditions, the CFS method has a linear range between 10 and 100 μg L-1 and a detection limit of 6.25 μg L-1 for the determination of Cr (VI). The sampling frequency is 10 samples per hour with a preconcentration time of 5 mins. Furthermore, after washing with a 0.1 M buffer (pH 3.0), the activity of the biosorbent is regenerated and remained comparable for more than 200 cycles. Scanning electron microscopy reveals a successful immobilization of biomass on eggshells powder and precipitation of Cr (VI) on the bacterial cell surface. The proposed method proves highly sensitive and could be suitable for the determination of Cr (VI) at an ultra-trace level.

scholarly journals Current Trends in Polymer Based Sensors

Chemosensors ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 108
Author(s):  
Giancarla Alberti ◽  
Camilla Zanoni ◽  
Vittorio Losi ◽  
Lisa Rita Magnaghi ◽  
Raffaela Biesuz
Keyword(s):  
Chemical Structure ◽  
Low Cost ◽  
Sensing Applications ◽  
Current Trends ◽  
Manufacturing Methods ◽  
New Devices

This review illustrates various types of polymer and nanocomposite polymeric based sensors used in a wide variety of devices. Moreover, it provides an overview of the trends and challenges in sensor research. As fundamental components of new devices, polymers play an important role in sensing applications. Indeed, polymers offer many advantages for sensor technologies: their manufacturing methods are pretty simple, they are relatively low-cost materials, and they can be functionalized and placed on different substrates. Polymers can participate in sensing mechanisms or act as supports for the sensing units. Another good quality of polymer-based materials is that their chemical structure can be modified to enhance their reactivity, biocompatibility, resistance to degradation, and flexibility.

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