Quantitative Studies of Long-term Stable, Top-down Fabricated Silicon Nanowire pH Sensor

2011 ◽  
Vol 1303 ◽  
Author(s):  
Sun Choi ◽  
Albert P. Pisano
Keyword(s):  
Silicon Nanowire ◽  
Ph Sensor ◽  
Sensor Response ◽  
Ph Sensitivity ◽  
Passivation Layer ◽  
Ph Sensors ◽  
Top Down ◽  
The Stability ◽  
Ph Level

ABSTRACTWe report simple and effective methods to develop long-term, stable silicon nanowire-based pH sensors and systematic studies of the performance of the developed sensors. In this work, we fabricate silicon nanowire pH sensors based on top-down fabrication processes such as E-beam lithography and conventional photolithography. In order to improve the stability of the sensor performance, the sensors are coated with a passivation layer (silicon nitride) for effective electrical insulation and ion-blocking. The stability, the pH sensitivity, and the repeatability of the sensor response are critically analyzed with regard to the physics of sensing interface between sample liquid and the sensing surface. The studies verify that the sensor with a passivation layer over critical thickness show long-term, stable sensor response without long-term drift. The studies also show the detection of pH level with silicon nanowire sensors is repeatable only after proper rinsing of sensor surfaces and there exists trade-off between the stability and the pH sensitivity of sensor response.

Quantitative studies of long-term stable, top-down fabricated silicon nanowire pH sensors

2012 ◽  
Vol 107 (2) ◽  
pp. 421-428 ◽  
Author(s):  
Sun Choi ◽  
Inkyu Park ◽  
Zhao Hao ◽  
Hoi-Ying N. Holman ◽  
Albert P. Pisano
Keyword(s):  
Silicon Nanowire ◽  
Ph Sensors ◽  
Top Down ◽  
Quantitative Studies

scholarly journals Ruthenium Oxide pH Sensing for Organs-On-Chip Studies

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 709 ◽  
Author(s):  
Esther Tanumihardja ◽  
Wouter Olthuis ◽  
Albert van den Berg
Keyword(s):  
Ph Sensor ◽  
Ruthenium Oxide ◽  
Open Circuit ◽  
Biological Medium ◽  
Similar Response ◽  
Ph Sensing ◽  
Ph Sensors ◽  
Cross Sensitivity ◽  
On Chip

A ruthenium oxide (RuOx) electrode is being developed as potentiometric pH sensor for organs-on-chip applications. Open-circuit potential (OCP) of the RuOx electrode showed a response of −58.05 mV/pH, with no cross-sensitivity to potentially interfering/complexing ions (tested were lithium, sulfate, chloride, and calcium ions). Similar response was observed in complex biological medium. The electrode stored in liquid had a long-term drift of −0.8 mV/hour (corresponding to ΔpH of 0.013/hour) and response time in complex biological medium was 3.7 s. Minimum cross-sensitivity to oxygen was observed as the OCP shifted ~3 mV going from deoxygenated to oxygenated solution. This response is one magnitude lower than previously reported for metal- oxide pH sensors. Overall, the RuOx pH sensor has proven to be a suitable pH sensor for organs- on-chip applications.

scholarly journals Ruthenium Oxide Nanorods as Potentiometric pH Sensor for Organs-On-Chip Purposes

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2901 ◽  
Author(s):  
Esther Tanumihardja ◽  
Wouter Olthuis ◽  
Albert van den Berg
Keyword(s):  
Ph Sensor ◽  
Ruthenium Oxide ◽  
Open Circuit ◽  
Ph Sensing ◽  
Ph Sensors ◽  
Oxide Nanorods ◽  
Order Of Magnitude ◽  
On Chip ◽  
Interfering Ions

A ruthenium oxide (RuOx) sensor for potentiometric pH sensing is currently being developed for organs-on-chip purposes. The sensor was fabricated from a Ru(OH)3 precursor, resulting in RuOx nanorods after heating. An open-circuit potential of the RuOx electrode showed a near-Nernstian response of −58.05 mV/pH, with good selectivity against potentially interfering ions (lithium, sulfate, chloride, and calcium ions). The preconditioned electrode (stored in liquid) had a long-term drift of −0.8 mV/h, and its response rate was less than 2 s. Sensitivity to oxygen was observed at an order of magnitude lower than other reported metal-oxide pH sensors. Together with miniaturizability, the RuOx pH sensor proves to be a suitable pH sensor for organs-on-chip studies.

Study of the pH Sensitivity of a Carbon-Paste Electrode Modified with Li0.31La0.56TiO3-xSrTiO3

2012 ◽  
Vol 554-556 ◽  
pp. 430-435
Author(s):  
Yue Hua Li ◽  
Jing Zhu ◽  
Lei Dai ◽  
Ling Wang
Keyword(s):  
Carbon Paste Electrode ◽  
Ph Sensor ◽  
Sensor Response ◽  
Ph Sensitivity ◽  
Carbon Paste ◽  
Linear Relationships ◽  
Perovskite Type ◽  
Paste Electrode

A novel sensitive pH sensor was reported based on a carbon paste electrode modified (CPEM) with perovskite-type Li0.31La0.56TiO3(LLTO) and LLTO-xSrTiO3(x =0.05~ 0.15) in order to investigate the influence of the doping in the sensor response. The carbon paste proves the ability of this perovskite to detect the variation of pH 2 -13. The LLTO-xSrTiO3(x =010)-CPEM indicated that the best linear relationships. A variation of potential in different pH-buffers was obtained with a response maximum of 32.08 mV/pH unit at 25◦C and 55.39 mV/pH unit at 70◦C for the better responding electrode.

scholarly journals Implementasi IoT Cerdas Berbasis Inference Fuzzy Tsukamoto pada Pemantauan Kadar pH dan Ketinggian Air dalam Akuaponik

2019 ◽  
Vol 3 (1) ◽  
pp. 65-74 ◽  
Author(s):  
Adlan Jiwa Kuswinta ◽  
I Gede Putu Wirama Wedashwara W ◽  
I Wayan Agus Arimbawa
Keyword(s):  
Urban Areas ◽  
Rapid Development ◽  
Fish Pond ◽  
Clean Water ◽  
Ph Sensors ◽  
Plant Cultivation ◽  
Different Types ◽  
The Stability ◽  
Ph Level ◽  
Water Height

The population of Mataram City amounted to 362,243 people in December 2008. The increase in population and rapid development caused a reduction in sources of clean water, especially in urban areas. In fish and plant cultivation it requires good water quality so that fish and plants are not exposed to parasites and diseases that cause fish and plants to die. Akuaponik uses water continuously from the maintenance of fish which is then distributed to plants, and then returned to the fish pond. This aquaponics system will be implemented with IoT using microcontrollers, ultrasonic sensors and pH sensors that will provide information through the website. The information will be given in the form of stability in the pH level of the water and the water level in the fish pond. Checking the stability of the pH level of the water and the height of the water is intended to maintain the plant so that it can absorb nutrients optimally from the water. One method that can be used to control pH levels based on water height by adding or reducing water is to create a system that can inform good results using fuzzy logic methods. The implementation of this system will be focused on plants using 2 different types of plants and evaluation carried out is only pattern recognition rather than optimization. To recognize patterns of change and adjust the height and pH of water in aquaponics to remain stable is to implement the concept of IoT and Inference Fuzzy Tsukamoto. The aquaponics system that is made can run well and shows information based on the results of fuzzy calculations.

The Stability of the WHO Reference Thromboplastin NIBS & C 67/40

1979 ◽  
Vol 42 (04) ◽  
pp. 1135-1140 ◽  
Author(s):  
G I C Ingram
Keyword(s):  
Human Brain ◽  
Collaborative Study ◽  
Calibration Constant ◽  
Long Term Stability ◽  
Freeze Dried ◽  
Show Evidence ◽  
Human Material ◽  
Reference Preparation ◽  
The Stability

SummaryThe International Reference Preparation of human brain thromboplastin coded 67/40 has been thought to show evidence of instability. The evidence is discussed and is not thought to be strong; but it is suggested that it would be wise to replace 67/40 with a new preparation of human brain, both for this reason and because 67/40 is in a form (like Thrombotest) in which few workers seem to use human brain. A �plain� preparation would be more appropriate; and a freeze-dried sample of BCT is recommended as the successor preparation. The opportunity should be taken also to replace the corresponding ox and rabbit preparations. In the collaborative study which would be required it would then be desirable to test in parallel the three old and the three new preparations. The relative sensitivities of the old preparations could be compared with those found in earlier studies to obtain further evidence on the stability of 67/40; if stability were confirmed, the new preparations should be calibrated against it, but if not, the new human material should receive a calibration constant of 1.0 and the new ox and rabbit materials calibrated against that.The types of evidence available for monitoring the long-term stability of a thromboplastin are discussed.

Application of the method of mathematical modeling for forecasting channel deformations at the underwater crossing of the main pipeline

2020 ◽  
Vol 10 (6) ◽  
pp. 599-609
Author(s):  
Valery А. Gruzdev ◽  
◽  
Georgy V. Mosolov ◽  
Ekaterina A. Sabayda ◽  
◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Roughness Coefficient ◽  
Computational Domain ◽  
Channel Deformations ◽  
Geological Surveys ◽  
Kuban River ◽  
The Stability ◽  
Protective Structures

In order to determine the possibility of using the method of mathematical modeling for making long-term forecasts of channel deformations of trunk line underwater crossing (TLUC) through water obstacles, a methodology for performing and analyzing the results of mathematical modeling of channel deformations in the TLUC zone across the Kuban River is considered. Within the framework of the work, the following tasks were solved: 1) the format and composition of the initial data necessary for mathematical modeling were determined; 2) the procedure for assigning the boundaries of the computational domain of the model was considered, the computational domain was broken down into the computational grid, the zoning of the computational domain was performed by the value of the roughness coefficient; 3) the analysis of the results of modeling the water flow was carried out without taking the bottom deformations into account, as well as modeling the bottom deformations, the specifics of the verification and calibration calculations were determined to build a reliable mathematical model; 4) considered the possibility of using the method of mathematical modeling to check the stability of the bottom in the area of TLUC in the presence of man-made dumping or protective structure. It has been established that modeling the flow hydraulics and structure of currents, making short-term forecasts of local high-altitude reshaping of the bottom, determining the tendencies of erosion and accumulation of sediments upstream and downstream of protective structures are applicable for predicting channel deformations in the zone of the TLUC. In all these cases, it is mandatory to have materials from engineering-hydro-meteorological and engineering-geological surveys in an amount sufficient to compile a reliable mathematical model.

Influence of internal and external risks on sustainability of financial system of Аltai krai

2018 ◽  
Vol 35 (4) ◽  
pp. 133-136
Author(s):  
R. N. Ibragimov
Keyword(s):  
Sustainable Development ◽  
Financial Stability ◽  
Management Strategy ◽  
Financial System ◽  
Risk Management Strategy ◽  
The Sustainable Development ◽  
The Stability ◽  
The Impact

The article examines the impact of internal and external risks on the stability of the financial system of the Altai Territory. Classification of internal and external risks of decline, affecting the sustainable development of the financial system, is presented. A risk management strategy is proposed that will allow monitoring of risks, thereby these measures will help reduce the loss of financial stability and ensure the long-term development of the economy of the region.

scholarly journals Long‐term study reveals top‐down effect of crabs on a California salt marsh

Ecosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Kathryn M. Beheshti ◽  
Kerstin Wasson ◽  
Christine Angelini ◽  
Brian R. Silliman ◽  
Brent B. Hughes
Keyword(s):  
Salt Marsh ◽  
Top Down ◽  
Term Study ◽  
Long Term Study

scholarly journals Titanium Nitride Thin Film Based Low-Redox-Interference Potentiometric pH Sensing Electrodes

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 42
Author(s):  
Shimrith Paul Shylendra ◽  
Wade Lonsdale ◽  
Magdalena Wajrak ◽  
Mohammad Nur-E-Alam ◽  
Kamal Alameh
Keyword(s):  
Thin Film ◽  
Titanium Nitride ◽  
Orange Juice ◽  
Ph Sensor ◽  
Reference Electrode ◽  
Cost Effective ◽  
Ph Sensing ◽  
Ph Sensors ◽  
Potential Shift ◽  
Double Junction

In this work, a solid-state potentiometric pH sensor is designed by incorporating a thin film of Radio Frequency Magnetron Sputtered (RFMS) Titanium Nitride (TiN) working electrode and a commercial Ag|AgCl|KCl double junction reference electrode. The sensor shows a linear pH slope of −59.1 mV/pH, R2 = 0.9997, a hysteresis as low as 1.2 mV, and drift below 3.9 mV/h. In addition, the redox interference performance of TiN electrodes is compared with that of Iridium Oxide (IrO2) counterparts. Experimental results show −32 mV potential shift (E0 value) in 1 mM ascorbic acid (reducing agent) for TiN electrodes, and this is significantly lower than the −114 mV potential shift of IrO2 electrodes with sub-Nernstian sensitivity. These results are most encouraging and pave the way towards the development of miniaturized, cost-effective, and robust pH sensors for difficult matrices, such as wine and fresh orange juice.

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