scholarly journals Electrochemical Deposition of Lead for Water Quality Sensing

Author(s):  
Anna M. Nelson ◽  
Sanaz Habibi ◽  
Jaesung Lee ◽  
Mark A. Burns

Abstract Lead contamination in drinking water can pose serious health risks to humans, and can often go undetected as a result of corrosion of lead infrastructure installed in buildings constructed prior to 1986. Thus, there is an unmet need for timely, cost-effective, and onsite monitoring of lead in drinking water. Here, we have designed a four-electrode system to reliably respond to electrodeposited lead oxide that provides a near real-time indication of lead presence. To better understand this detection mechanism, we investigated the temporal and spatial electrochemical deposition of lead using potential response data, scanning electron microscopy (SEM), fractal dimension (fD), and COMSOL Multiphysics® finite element analysis. Our results suggest that the deposition of lead oxide on the sensor is diffusion limited. Such fundamental understanding of the detection mechanism is critical to improve and shorten the detection time of the sensor. We used this information to improve the detection time and reliability of the signal by reducing the electrode gap distance and agitating the solution. This study provides a path for further optimization of a continuous electrochemical sensor for onsite monitoring of lead in drinking water.

2015 ◽  
Vol 20 (9) ◽  
pp. 1091-1100 ◽  
Author(s):  
Kent R. Gordon ◽  
Yuli Wang ◽  
Nancy L. Allbritton ◽  
Anne Marion Taylor

High-throughput screening (HTS) on neurons presents unique difficulties because they are postmitotic, limited in supply, and challenging to harvest from animals or generate from stem cells. These limitations have hindered neurological drug discovery, leaving an unmet need to develop cost-effective technology for HTS using neurons. Traditional screening methods use up to 20,000 neurons per well in 384-well plates. To increase throughput, we use “microraft” arrays, consisting of 1600 square, releasable, paramagnetic, polystyrene microelements (microrafts), each providing a culture surface for 500–700 neurons. These microrafts can be detached from the array and transferred to 384-well plates for HTS; however, they must be centered within wells for automated imaging. Here, we developed a magnet array plate, compatible with HTS fluid-handling systems, to center microrafts within wells. We used finite element analysis to select an effective size of the magnets and confirmed that adjacent magnetic fields do not interfere. We then experimentally tested the plate’s centering ability and found a centering efficiency of 100%, compared with 4.35% using a flat magnet. We concluded that microrafts could be centered after settling randomly within the well, overcoming friction, and confirmed these results by centering microrafts containing hippocampal neurons cultured for 8 days.


2009 ◽  
Vol 06 (01) ◽  
pp. 5-9 ◽  
Author(s):  
S. Aguilar-Gaxiola ◽  
J. Alonso ◽  
S. Chatterji ◽  
S. Lee ◽  
T. B. Üstün ◽  
...  

SummaryThe paper presents an overview of the WHO World Mental Health (WMH) Survey Initiative and summarizes recent WMH results regarding the prevalence and societal costs of mental disorders. The WMH surveys are representative community surveys that were carried out in 28 countries throughout the world aimed at providing information to mental health policy makers about the prevalence, burden, and unmet need for treatment of common mental disorders. Results show that mental disorders are commonly occurring in all participating countries. The inter-quartile range (IQR: 25th-75th percentiles) of lifetime DSM-IV disorder prevalence estimates (combining anxiety, mood, disruptive behavior, and substance disorders) is 18.1-36.1%. The IQR of 12-month prevalence estimates is 9.8-19.1%. Analysis of age-of-onset reports shows that many mental disorders begin in childhood-adolescence and have significant adverse effects on subsequent role transitions. Adult mental disorders are found in the WMH data to be associated with high levels of role impairment. Despite this burden, the majority of mental disorders go untreated. Although these results suggest that expansion of treatment could be cost-effective from both the employer perspective and the societal perspective, treatment effectiveness trials are needed to confirm this suspicion. The WMH results regarding impairments are being used to target several such interventions.


2011 ◽  
Vol 39 (3) ◽  
pp. 193-209 ◽  
Author(s):  
H. Surendranath ◽  
M. Dunbar

Abstract Over the last few decades, finite element analysis has become an integral part of the overall tire design process. Engineers need to perform a number of different simulations to evaluate new designs and study the effect of proposed design changes. However, tires pose formidable simulation challenges due to the presence of highly nonlinear rubber compounds, embedded reinforcements, complex tread geometries, rolling contact, and large deformations. Accurate simulation requires careful consideration of these factors, resulting in the extensive turnaround time, often times prolonging the design cycle. Therefore, it is extremely critical to explore means to reduce the turnaround time while producing reliable results. Compute clusters have recently become a cost effective means to perform high performance computing (HPC). Distributed memory parallel solvers designed to take advantage of compute clusters have become increasingly popular. In this paper, we examine the use of HPC for various tire simulations and demonstrate how it can significantly reduce simulation turnaround time. Abaqus/Standard is used for routine tire simulations like footprint and steady state rolling. Abaqus/Explicit is used for transient rolling and hydroplaning simulations. The run times and scaling data corresponding to models of various sizes and complexity are presented.


2012 ◽  
Vol 35 (12) ◽  
pp. 2562
Author(s):  
Chao WANG ◽  
Zhong-Chuan FU ◽  
Hong-Song CHEN ◽  
Gang CUI

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 899
Author(s):  
Djordje Mitrovic ◽  
Miguel Crespo Chacón ◽  
Aida Mérida García ◽  
Jorge García Morillo ◽  
Juan Antonio Rodríguez Diaz ◽  
...  

Studies have shown micro-hydropower (MHP) opportunities for energy recovery and CO2 reductions in the water sector. This paper conducts a large-scale assessment of this potential using a dataset amassed across six EU countries (Ireland, Northern Ireland, Scotland, Wales, Spain, and Portugal) for the drinking water, irrigation, and wastewater sectors. Extrapolating the collected data, the total annual MHP potential was estimated between 482.3 and 821.6 GWh, depending on the assumptions, divided among Ireland (15.5–32.2 GWh), Scotland (17.8–139.7 GWh), Northern Ireland (5.9–8.2 GWh), Wales (10.2–8.1 GWh), Spain (375.3–539.9 GWh), and Portugal (57.6–93.5 GWh) and distributed across the drinking water (43–67%), irrigation (51–30%), and wastewater (6–3%) sectors. The findings demonstrated reductions in energy consumption in water networks between 1.7 and 13.0%. Forty-five percent of the energy estimated from the analysed sites was associated with just 3% of their number, having a power output capacity >15 kW. This demonstrated that a significant proportion of energy could be exploited at a small number of sites, with a valuable contribution to net energy efficiency gains and CO2 emission reductions. This also demonstrates cost-effective, value-added, multi-country benefits to policy makers, establishing the case to incentivise MHP in water networks to help achieve the desired CO2 emissions reductions targets.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Aidan Kenny ◽  
Eva M. Jiménez-Mateos ◽  
María Ascensión Zea-Sevilla ◽  
Alberto Rábano ◽  
Pablo Gili-Manzanaro ◽  
...  

Abstract Alzheimer’s disease (AD) is characterized by a progressive loss of neurons and cognitive functions. Therefore, early diagnosis of AD is critical. The development of practical and non-invasive diagnostic tests for AD remains, however, an unmet need. In the present proof-of-concept study we investigated tear fluid as a novel source of disease-specific protein and microRNA-based biomarkers for AD development using samples from patients with mild cognitive impairment (MCI) and AD. Tear protein content was evaluated via liquid chromatography-mass spectrometry and microRNA content was profiled using a genome-wide high-throughput PCR-based platform. These complementary approaches identified enrichment of specific proteins and microRNAs in tear fluid of AD patients. In particular, we identified elongation initiation factor 4E (eIF4E) as a unique protein present only in AD samples. Total microRNA abundance was found to be higher in tears from AD patients. Among individual microRNAs, microRNA-200b-5p was identified as a potential biomarker for AD with elevated levels present in AD tear fluid samples compared to controls. Our study suggests that tears may be a useful novel source of biomarkers for AD and that the identification and verification of biomarkers within tears may allow for the development of a non-invasive and cost-effective diagnostic test for AD.


Author(s):  
Rama Subba Reddy Gorla

Heat transfer from a nuclear fuel rod bumper support was computationally simulated by a finite element method and probabilistically evaluated in view of the several uncertainties in the performance parameters. Cumulative distribution functions and sensitivity factors were computed for overall heat transfer rates due to the thermodynamic random variables. These results can be used to identify quickly the most critical design variables in order to optimize the design and to make it cost effective. The analysis leads to the selection of the appropriate measurements to be used in heat transfer and to the identification of both the most critical measurements and the parameters.


2012 ◽  
Vol 8 ◽  
pp. 34-37
Author(s):  
Arshad Ali ◽  
Hashim Nissar Hasim ◽  
Ashfaq Ahmad ◽  
Intikhab Ahmad Qureashi

Pakistan is subjected to rapid water shortage due to different social and environmental problems. Moreover, the drinking water is being contaminated at an alarming rate that is mostly due to the discharge of untreated domestic and industrial effluent and agricultural run-off. Therefore, this study was designed to evaluate the water quality problems of the subject area and to determine a cost effective treatment technique. The main objective was to determine the removal efficiency of microbial contamination using flocculant settling. The main pollutants identified by conducting water quality tests are arsenic, fluoride, nitrates and microbial contamination. The maximum concentration of arsenic, fluoride, nitrates and microbial contamination were observed as 12ppb, 2.2mg/L, 26mg/L and 84 colonies/100mL, respectively. During discrete settling tests performed in a 12cft column, it was noticed that the removal of microbial contamination corresponding to a detention time of 225min is 26.7% only. While working on different coagulants, it was observed that the optimum alum, lime and magnesium dosage for the removal of microbial contamination is 31.5mg/L, 10.5mg/L and 27mg/L respectively. The final results of the study suggest that the use of lime as a coagulant to improve the quality of water in terms of microbial contamination is an effective and reliable technique, both in terms of its treatability performance and cost-effectiveness, which was noticed to be 77.7%.DOI: http://dx.doi.org/10.3126/hn.v8i0.4909Hydro Nepal: Journal of Water, Energy and Environment Issue No. 8, 2011 JanuaryPage: 34-37Uploaded date: 17 June, 2011


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