scholarly journals Laser-Tunable Printed ZnO Nanoparticles for Paper-Based UV Sensors with Reduced Humidity Interference

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 80
Author(s):  
Georges Dubourg ◽  
Marko Radović ◽  
Borislav Vasić
Keyword(s):  
Zno Nanoparticles ◽  
Laser Processing ◽  
Low Cost ◽  
Processing Method ◽  
Paper Substrate ◽  
Cross Sensitivity ◽  
Uv Sensitivity ◽  
The Cross ◽  
Uv Sensors ◽  
First Time

Development of paper-based sensors that do not suffer with humidity interference is desirable for practical environmental applications. In this work, a laser processing method was reported to effectively modulate the cross-sensitivity to humidity of ZnO-based UV (Ultraviolet) sensors printed on paper substrate. The results reveal that the laser induced zinc oxide (ZnO) surface morphology contributes to the super-hydrophobicity of the printed ZnO nanoparticles, reducing humidity interference while enhancing UV sensitivity. Herein, this conducted research highlights for the first time that laser processing is an attractive choice that reduces the cross-sensitivity to water vapor in the UV sensing response of ZnO-based devices printed on paper, paving the way to low-cost and sophisticated paper-based sensors.

scholarly journals Tilted Fiber Bragg Grating Sensor Using Chemical Plating of a Palladium Membrane for the Detection of Hydrogen Leakage

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4478 ◽  
Author(s):  
Jiachen Yu ◽  
Zhenlin Wu ◽  
Xin Yang ◽  
Xiuyou Han ◽  
Mingshan Zhao
Keyword(s):  
Fiber Bragg Grating ◽  
Low Cost ◽  
Hydrogen Sensor ◽  
Bragg Grating ◽  
Wavelength Shift ◽  
Cross Sensitivity ◽  
Chemical Plating ◽  
Palladium Membrane ◽  
Surrounding Refractive Index ◽  
The Cross

A tilted fiber Bragg grating (TFBG) hydrogen sensor coated with a palladium (Pd) membrane by the electroless plating method is proposed in this paper. A uniform layer of Pd metal is fabricated in aqueous solutions by the chemical coating method, which is used as the sensitive element to detect the change of the surrounding refractive index (SRI) caused by hydrogen absorption. The change in SRI causes an unsynchronized change of the cladding modes and the Bragg peak in the TFBG transmission spectrum, thereby eliminating the cross-sensitivity due to membrane expansion and is able to simultaneously monitor the presence of cracks in the pipe, as well as the hydrogen leakage. By subtracting the wavelength shift caused by fiber expansion, the change of SRI, i.e., the information from the H2 level, can be separately obtained. The drifted wavelength is measured for the H2 concentration below the hydrogen explosion limit between 1% and 4%. The chemical-based coating has the advantages of a low cost, a simple operation, and being suitable for coating on long fiber structures. The proposed sensor is able to detect the H2 signal in 5 min at a 1% H2 concentration. The proposed sensor is proved to be able to monitor the hydrogen level without the cross-sensitivity of temperature variation and expansion strains, so could be a good candidate for security applications in industry.

Starch-Cellulose-Based Triboelectric Nanogenerator Obtained by a Low-Cost Cleanroom-Free Processing Method

MRS Advances ◽  
2019 ◽  
Vol 4 (23) ◽  
pp. 1315-1320 ◽  
Author(s):  
Robert Ccorahua ◽  
Alexsandra Cordero ◽  
Clemente Luyo ◽  
María Quintana ◽  
Emir Vela
Keyword(s):  
Film Thickness ◽  
Chemical Modification ◽  
State Of The Art ◽  
Low Cost ◽  
Processing Method ◽  
The State ◽  
Triboelectric Nanogenerator ◽  
Micro Fabrication ◽  
Complex Equipment ◽  
First Time

To date only few low-cost bio-based materials have been reported to be useful as TENGs. However, they still keep employing costly nanofabrication techniques. Herein, a new bio-based starch-cellulose TENG is fabricated without using complex equipment for the first time. Our results showed that, depending on the film thickness, electric outputs varied from 60 mV to 300 mV per 4 cm2 area. The thicker the film, the lower the electrical outputs, and vice versa. Moreover, FTIR-ATR analysis also showed that no chemical modification was made on the surface of starch after casting. Therefore, starch remained unmodified at the time of characterization, being this performance proper of a pristine starch. In addition, though organic starch isolation, fabrication of the proposed TENG was entirely handmade, thus avoiding use of complex equipment of nano- and micro-fabrication which resulted in the development of an eco-friendly TENG with very good performance according to the state-of-the-art.

scholarly journals Laser Processed Oxygen-Free High-Conductivity Copper with Ti and Ti–Zr–V–Hf Films Applied in Neutron Tube

2019 ◽  
Vol 9 (22) ◽  
pp. 4940
Author(s):  
Jie Wang ◽  
Yong Gao ◽  
Zhiming You ◽  
Jiakun Fan ◽  
Jing Zhang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Laser Processing ◽  
Secondary Electron ◽  
Electron Cloud ◽  
Processing Method ◽  
High Conductivity ◽  
Particle Accelerators ◽  
Secondary Electrons ◽  
Neutron Tube ◽  
First Time

The laser processing method has proven to produce surfaces while ensuring a low secondary electron yield of oxygen-free high-conductivity copper (OFHC) samples, making it attractive for electron cloud mitigation in next-generation particle accelerators and neutron tubes. In this work, the laser processing method is proposed to OFHC targets for the first time, aiming to reduce the secondary electrons in the neutron tube. The secondary electron yields (SEYs) and the thermal conductivities of Ti film and quaternary Ti–Zr–V–Hf films with unprocessed and laser processed OFHC substrates are investigated. Our results highlight that the thermal conductivity of Ti film with laser processed OFHC substrates is in proximity to the cleaned bare OFHC sample, especially at high temperatures. Moreover, the SEY of coated OFHC substrates are higher than that of coated laser processed substrates, which indicates the better secondary electron suppression capability of coated laser processed substrates. Therefore, the thermal conductivity and SEY results illustrate that the application of Ti and Ti–Zr–V–Hf coated laser processed OFHC can be considered to improve the neutron yield in neutron tubes in the future.

scholarly journals The Effect of Surfactant-Modified Montmorillonite on the Cross-Linking Efficiency of Polysiloxanes

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2623
Author(s):  
Monika Wójcik-Bania ◽  
Jakub Matusik
Keyword(s):  
Total Pore Volume ◽  
Cross Linking ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
The Cross ◽  
Chain Lengths ◽  
First Time ◽  
Substituent Influence ◽  
Benzyl Substituent

Polymer–clay mineral composites are an important class of materials with various applications in the industry. Despite interesting properties of polysiloxanes, such matrices were rarely used in combination with clay minerals. Thus, for the first time, a systematic study was designed to investigate the cross-linking efficiency of polysiloxane networks in the presence of 2 wt % of organo-montmorillonite. Montmorillonite (Mt) was intercalated with six quaternary ammonium salts of the cation structure [(CH3)2R’NR]+, where R = C12, C14, C16, and R’ = methyl or benzyl substituent. The intercalation efficiency was examined by X-ray diffraction, CHN elemental analysis, and Fourier transform infrared (FTIR) spectroscopy. Textural studies have shown that the application of freezing in liquid nitrogen and freeze-drying after the intercalation increases the specific surface area and the total pore volume of organo-Mt. The polymer matrix was a poly(methylhydrosiloxane) cross-linked with two linear vinylsiloxanes of different siloxane chain lengths between end functional groups. X-ray diffraction and transmission electron microscopy studies have shown that the increase in d-spacing of organo-Mt and the benzyl substituent influence the degree of nanofillers’ exfoliation in the nanocomposites. The increase in the degree of organo-Mt exfoliation reduces the efficiency of hydrosilylation reaction monitored by FTIR. This was due to physical hindrance induced by exfoliated Mt particles.

scholarly journals UV Inscription and Pressure Induced Long-Period Gratings through 3D Printed Amplitude Masks

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1977
Author(s):  
Ricardo Oliveira ◽  
Liliana M. Sousa ◽  
Ana M. Rocha ◽  
Rogério Nogueira ◽  
Lúcia Bilro
Keyword(s):  
State Of The Art ◽  
Low Cost ◽  
Resonance Wavelength ◽  
Complex Structures ◽  
Pressing Method ◽  
Long Period ◽  
Long Period Gratings ◽  
3D Printed ◽  
Mechanical Pressing ◽  
First Time

In this work, we demonstrate for the first time the capability to inscribe long-period gratings (LPGs) with UV radiation using simple and low cost amplitude masks fabricated with a consumer grade 3D printer. The spectrum obtained for a grating with 690 µm period and 38 mm length presented good quality, showing sharp resonances (i.e., 3 dB bandwidth < 3 nm), low out-of-band loss (~0.2 dB), and dip losses up to 18 dB. Furthermore, the capability to select the resonance wavelength has been demonstrated using different amplitude mask periods. The customization of the masks makes it possible to fabricate gratings with complex structures. Additionally, the simplicity in 3D printing an amplitude mask solves the problem of the lack of amplitude masks on the market and avoids the use of high resolution motorized stages, as is the case of the point-by-point technique. Finally, the 3D printed masks were also used to induce LPGs using the mechanical pressing method. Due to the better resolution of these masks compared to ones described on the state of the art, we were able to induce gratings with higher quality, such as low out-of-band loss (0.6 dB), reduced spectral ripples, and narrow bandwidths (~3 nm).

Association between the FINDRISC score and the risk of metabolic syndrome and hepatic steatosis

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
D Godoi Bernardes Da Silva ◽  
R Dias Santos ◽  
M Sommer Bittencourt ◽  
J.A.M Carvalho ◽  
M Franken ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Hepatic Steatosis ◽  
Longitudinal Analysis ◽  
Metabolic Diseases ◽  
Low Cost ◽  
Cross Sectional ◽  
Predictive Values ◽  
Cross Sectional Analysis ◽  
The Cross ◽  
Sectional Analysis

Abstract Introduction The Finnish Diabetes Risk Score (FINDRISC) was developed in Europe to predict type 2 diabetes mellitus (T2DM) risk without need of laboratory tests. Small cross-sectional studies analyzed the association between RF with metabolic syndrome (MS) or hepatic steatosis (HS). Our objective was to test the association of FINDRISC with MS or HS, in a transversal and longitudinal way. Methods In 41,668 individuals (age 41.9±9.7 years; 30.8% women) who underwent health evaluation between 2008 and 2016 in a single centre in Brazil, we tested the transversal association between FINDRISC and MS or HS, in multivariate models. The same analyzes were performed longitudinally in non-diabetic subgroups, followed for 5±3 years, to test the predictive value of FINDRISC and the incidental risk of MS (n=10,075 individuals) or HS (n=7,097 individuals), using logistic regression. Models were adjusted for confounders such as sex, use of medications for dyslipidemia, smoking, and baseline plasma levels of glucose, creatinine and lipids. A receiver operating characteristic (ROC) curve was used to evaluate the discriminative and predictive values of FINDRISC for MS and HS. Results In the cross-sectional analysis, 2,252 (5%) individuals had MS and 14,176 (34%) HS. In the longitudinal analysis, there were 302 cases of incidental MS (2%) and 1,096 cases of HS (15%). FINDRISC was independently associated with MS and HS in the cross-sectional analysis (respectively, OR 1.27, 95% CI: 1.25–1.28, P&lt;0.001; and OR 1.21, 95% CI: 1.20–1.22, P&lt;0.001, per FINDRISC unit) and in longitudinal analysis (respectively, OR of 1.18, 95% CI: 1.15–1.21, P&lt;0.001; and OR of 1.10, 95% CI: 1.08–1.11, P&lt;0.001, per FINDRISC unit). In comparison with individuals with low FINDRISC, those with moderate, high and very high values showed significant and proportional increases of the 12 to 77 fold in the chance of current SM (P&lt;0.001) and 3 to 10 fold in the chance of HS (P&lt;0.001). During follow-up, these increases were 3 to 10 fold in the chance of incidental MS (P&lt;0.001) and 1 to 3 fold in the chance of HS (P&lt;0.001). The AUC from cross-sectional analysis for MS and HS were respectively 0.82 (95% CI 0.81–0.83) and 0.76 (95% CI 0.75–0.76), and in longitudinal analysis 0.73 (95% CI 0.70–0.76) and 0.63 (95% CI 0.61–0.65), respectively. Conclusion FINDRISC was associated with the presence and onset of MS and HS, but it predicted better metabolic syndrome risk than hepatic steatosis. Therefore, this simple, practical and low-cost score can be useful for population screening and identification of subgroups of individuals at higher risk future metabolic diseases. Funding Acknowledgement Type of funding source: None

scholarly journals Competition Effects during Femtosecond Laser Induced Element Redistribution in Ba- and La-Migration Based Laser Written Waveguides

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3185
Author(s):  
Manuel Macias-Montero ◽  
Pedro Moreno-Zárate ◽  
Francisco Muñoz ◽  
Belén Sotillo ◽  
Marina Garcia-Pardo ◽  
...  
Keyword(s):  
Laser Processing ◽  
Optical Waveguides ◽  
Phosphate Glasses ◽  
Competition Effect ◽  
Competition Effects ◽  
Fs Laser ◽  
Index Contrast ◽  
The Cross ◽  
Element Redistribution ◽  
Element Migration

Fs-laser induced element redistribution (FLIER) has been a subject of intensive research in recent years. Its application to various types of glasses has already resulted in the production of efficient optical waveguides, tappers, amplifiers and lasers. Most of the work reported on FLIER-based waveguides refers to structures produced by the cross-migration of alkali (Na, K) and lanthanides (mostly La). The latter elements act as refractive index carrying elements. Herein, we report the production of Ba-based, FLIER-waveguides in phosphate glass with an index contrast > 10−2. Phosphate glasses modified with the same amount of Na2O and K2O, and variable amounts of BaO and/or La2O3 were used to produce the FLIER-waveguides with Ba and or La acting as index carriers. Ba-only modified glasses show a waveguide writing threshold and light guiding performance comparable to that of La-based structures. However, mixed Ba-La glasses show a much higher element migration threshold, and much smaller compositionally modified regions. This behavior is consistent with a competition effect in the cross-migration of both elements (Ba and La) against the alkalis. Such an effect can be applied to inhibit undesired element redistribution effects in fs-laser processing applications in multicomponent glasses.

scholarly journals Fabrication of Porous Silicon Based Humidity Sensing Elements on Paper

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Tero Jalkanen ◽  
Anni Määttänen ◽  
Ermei Mäkilä ◽  
Jaani Tuura ◽  
Martti Kaasalainen ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Smart Cities ◽  
Low Cost ◽  
Electrical Characterization ◽  
Fabrication Process ◽  
Sensing Element ◽  
Paper Substrate ◽  
Roll To Roll ◽  
Silver Electrodes ◽  
Silicon Based

A roll-to-roll compatible fabrication process of porous silicon (pSi) based sensing elements for a real-time humidity monitoring is described. The sensing elements, consisting of printed interdigitated silver electrodes and a spray-coated pSi layer, were fabricated on a coated paper substrate by a two-step process. Capacitive and resistive responses of the sensing elements were examined under different concentrations of humidity. More than a three orders of magnitude reproducible decrease in resistance was measured when the relative humidity (RH) was increased from 0% to 90%. A relatively fast recovery without the need of any refreshing methods was observed with a change in RH. Humidity background signal and hysteresis arising from the paper substrate were dependent on the thickness of sensing pSi layer. Hysteresis in most optimal sensing element setup (a thick pSi layer) was still noticeable but not detrimental for the sensing. In addition to electrical characterization of sensing elements, thermal degradation and moisture adsorption properties of the paper substrate were examined in connection to the fabrication process of the silver electrodes and the moisture sensitivity of the paper. The results pave the way towards the development of low-cost humidity sensors which could be utilized, for example, in smart packaging applications or in smart cities to monitor the environment.

Printing ultrathin graphene oxide nanofiltration membranes for water purification

2017 ◽  
Vol 5 (39) ◽  
pp. 20860-20866 ◽  
Author(s):  
Mahdi Fathizadeh ◽  
Huynh Ngoc Tien ◽  
Konstantin Khivantsev ◽  
Jung-Tsai Chen ◽  
Miao Yu
Keyword(s):  
Graphene Oxide ◽  
Water Purification ◽  
Inkjet Printing ◽  
Low Cost ◽  
Nanofiltration Membranes ◽  
Highly Effective ◽  
First Time ◽  
Polymeric Supports ◽  
Effective Water

We demonstrated for the first time that inkjet printing can be a low-cost, easy, fast, and scalable method for depositing ultrathin (7.5–60 nm) uniform graphene oxide (GO) nanofiltration membranes on polymeric supports for highly effective water purification.

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