scholarly journals Methodology to Create Reproducible Validation/Reference Materials for Comparison of Filter-Based Measurements of Carbonaceous Aerosols That Measure BC, BrC, EC, OC, and TC

Metrology ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 142-165
Author(s):  
Paul A. Solomon ◽  
Anna-Marie Hyatt ◽  
Anthony D. A. Hansen ◽  
James J. Schauer ◽  
Nicole P. Hyslop ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Glass Fiber ◽  
Reference Materials ◽  
Coefficient Of Variation ◽  
Total Carbon ◽  
Filter Media ◽  
Simple Method ◽  
Coated Glass ◽  
Optical Attenuation ◽  
Better Than

A simple method that reproducibly creates validation/reference materials for comparison of methods that measure the carbonaceous content of atmospheric particulate matter deposited on filter media at concentrations relevant to atmospheric levels has been developed and evaluated. Commonly used methods to determine the major carbonaceous components of particles collected on filters include optical attenuation for “Black” (BC) and “Brown” (BrC) carbon, thermal-optical analysis (TOA) for “Elemental” (EC) and “Organic” (OC) carbon, and total combustion for “Total” carbon (TC). The new method uses a commercial inkjet printer to deposit ink containing both organic and inorganic components onto filter substrates at programmable print densities (print levels, as specified by the printer–software combination). A variety of filter media were evaluated. The optical attenuation (ATN) of the deposited sample was determined at 880 nm and 370 nm. Reproducibility or precision (as standard deviation or in percent as coefficient of variation) in ATN for Teflon-coated glass-fiber, Teflon, and cellulose substrates was better than 5%. Reproducibility for other substrates was better than 15%. EC and OC measured on quartz-fiber filters (QFF) compared to ATN measured at 880 nm and 370 nm on either QFF or Teflon-coated glass-fiber yielded R2 > 0.92 and >0.97, respectively. Four independent laboratories participated in a round robin study together with the reference laboratory. The propagated standard deviation among the five groups across all print levels was <2.2 ATN at 880 nm and <2.7 ATN at 370 nm with a coefficient of variation of <2% at ~100 ATN.

scholarly journals Study on the coefficient of variation in indian personnel monitoring system

2016 ◽  
Vol 31 (4) ◽  
pp. 388-392
Author(s):  
Sneha Chandrasekhar ◽  
Suresh Pradhan ◽  
Madhumita Bhattacharya ◽  
Ratna Pradeep ◽  
Debabrata Datta
Keyword(s):  
Standard Deviation ◽  
Monitoring System ◽  
Dose Level ◽  
Coefficient Of Variation ◽  
International Electrotechnical Commission ◽  
Routine Monitoring ◽  
Dose Levels ◽  
Higher Doses ◽  
Measurable Range ◽  
Better Than

The primary parameters for testing an individual monitoring system are standard deviation and the coefficient of variation. The International Electrotechnical Commission (IEC) standard 62387-1 recommends testing the coefficient of variation of dosemeters for various doses because the acceptable coefficient of variation changes with the dose level. However, for dose quantity Hp(10), i. e. doses greater than 1.1 mSv, the acceptable limit is 5 % and remains unchanged up to the highest dose in the measurable range. This study was carried out to confirm whether the same is followed in the Indian personnel monitoring system when measuring Hp(10) and also in order to study the variation in the coefficient of variation with a given dose. It was observed that even if the coefficient of variation at doses between 0.1 mSv and 1.1 mSv is lower than the IEC requirement, at higher doses, the same may not be true. In routine monitoring, since the anticipated doses are less than 1 mSv, a monitoring system which performs better than the IEC requirement at these levels of doses is an advantage. However, good performance at said dose levels does not naturally indicate good performance at higher doses.

Evaluation of Filter Media Options for High Volume PM2.5 Sampling

2019 ◽  
Vol 35 (2) ◽  
pp. 205-209
Author(s):  
Huan Li ◽  
John D. Wanjura ◽  
William B. Faulkner ◽  
Ronald E. Lacey
Keyword(s):  
Standard Deviation ◽  
Glass Fiber ◽  
Cellulose Fiber ◽  
Sampling Technique ◽  
High Volume ◽  
Ambient Particulate Matter ◽  
Weight Changes ◽  
Filter Media ◽  
Replicated Measurements ◽  
Improved Performance

Abstract. Polytetrafluoroethylene (PTFE), glass fiber, and cellulose fiber filter media were evaluated under controlled conditions to determine their suitability for high volume PM2.5 sampling. Repeated mounting and unmounting events of new filters not exposed to ambient particulate matter were conducted in a laboratory environment and differences in the filter weight recorded. After the initial mounting and unmounting event, the filters exhibited weight changes of -2.24 mg, -0.61 mg, and 0.18 mg for cellulose, PTFE, and glass fiber filters, respectively. The standard deviation of replicated measurements after the first event was 1.76 (n = 9), 0.50 (n = 10), and 0.31 (n = 10) for cellulose, PTFE, and glass fiber filters, respectively. The combination of weight loss and standard deviation made the cellulose filter unsuitable for use in high volume PM2.5 samplers. However, improved performance over PTFE filters, suggests that glass fiber filters similar in specification to PTFE filters should be considered as acceptable substitutes in high volume PM2.5 sampling. Keywords: Air quality, Error, Filters, Measurement, Particles, Sampling technique.

Using Connectionist Modules for Decision Support

1990 ◽  
Vol 29 (03) ◽  
pp. 167-181 ◽  
Author(s):  
G. Hripcsak
Keyword(s):  
Decision Support ◽  
Standard Deviation ◽  
Confidence Interval ◽  
Posterior Probability ◽  
Back Propagation ◽  
Connectionist Model ◽  
Test Set ◽  
The Third ◽  
Independent Test ◽  
Better Than

AbstractA connectionist model for decision support was constructed out of several back-propagation modules. Manifestations serve as input to the model; they may be real-valued, and the confidence in their measurement may be specified. The model produces as its output the posterior probability of disease. The model was trained on 1,000 cases taken from a simulated underlying population with three conditionally independent manifestations. The first manifestation had a linear relationship between value and posterior probability of disease, the second had a stepped relationship, and the third was normally distributed. An independent test set of 30,000 cases showed that the model was better able to estimate the posterior probability of disease (the standard deviation of residuals was 0.046, with a 95% confidence interval of 0.046-0.047) than a model constructed using logistic regression (with a standard deviation of residuals of 0.062, with a 95% confidence interval of 0.062-0.063). The model fitted the normal and stepped manifestations better than the linear one. It accommodated intermediate levels of confidence well.

Research of the activity and viability of spermatozoa at different concentrations and proportions of diluents after incubation

2020 ◽  
pp. 88-95
Author(s):  
Svitlana Lobchenko ◽  
Tetiana Husar ◽  
Viktor Lobchenko
Keyword(s):  
Plasma Concentration ◽  
Incubation Time ◽  
Coefficient Of Variation ◽  
Incubation Medium ◽  
Wide Range ◽  
Series Of Experiments ◽  
The Subject ◽  
Boar Spermatozoa ◽  
Native Plasma ◽  
Better Than

The results of studies of the viability of spermatozoa with different incubation time at different concentrations and using different diluents are highlighted in the article. (Un) concentrated spermatozoa were diluented: 1) with their native plasma; 2) medium 199; 3) a mixture of equal volumes of plasma and medium 199. The experiment was designed to generate experimental samples with spermatozoa concentrations prepared according to the method, namely: 0.2; 0.1; 0.05; 0.025 billion / ml. The sperm was evaluated after 2, 4, 6 and 8 hours. The perspective of such a study is significant and makes it possible to research various aspects of the subject in a wide range. In this regard, a series of experiments were conducted in this area. The data obtained are statistically processed and allow us to highlight the results that relate to each stage of the study. In particular, in this article it was found out some regularities between the viability of sperm, the type of diluent and the rate of rarefaction, as evidenced by the data presented in the tables. As a result of sperm incubation, the viability of spermatozoa remains at least the highest trend when sperm are diluted to a concentration of 0.1 billion / ml, regardless of the type of diluent used. To maintain the viability of sperm using this concentration of medium 199 is not better than its native plasma, and its mixture with an equal volume of plasma through any length of time incubation of such sperm. Most often it is at this concentration of sperm that their viability is characterized by the lowest coefficient of variation, regardless of the type of diluent used, which may indicate the greatest stability of the result under these conditions. The viability of spermatozoa with a concentration of 0.1 billion / ml is statistically significantly reduced only after 6 or even 8 hours of incubation. If the sperm are incubated for only 2 hours, regardless of the type of diluent used, the sperm concentrations tested do not affect the viability of the sperm. Key words: boar, spermatozoa, sperm plasma, concentration, incubation, medium 199, activity, viability, rarefaction.

scholarly journals Water Influence on the Uniaxial Tensile Behavior of Polytetrafluoroethylene-Coated Glass Fiber Fabric

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 846
Author(s):  
Hastia Asadi ◽  
Joerg Uhlemann ◽  
Natalie Stranghoener ◽  
Mathias Ulbricht
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Operation Time ◽  
Uniaxial Tensile ◽  
Membrane Structures ◽  
Strength Deterioration ◽  
Coated Glass ◽  
Reversible Loss ◽  
The Impact ◽  
Loss Of Strength

Polytetrafluoroethylene (PTFE)-coated glass fiber fabrics are used for long-lasting membrane structures due to their outstanding mechanical properties, chemical stabilities, and satisfying service life. During their operation time, different environmental impacts might influence their performance, especially regarding the mechanical properties. In this contribution, the impact of water on the tensile strength deterioration was assessed experimentally, providing evidence of considerable but partially reversible loss of strength by up to 20% among the various types of investigated industrially established fabrics.

scholarly journals Fish bone-derived interconnected carbon nanofibers for efficient and lightweight microwave absorption

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Yangyang Gu ◽  
Peng Dai ◽  
Wen Zhang ◽  
Zhanwen Su
Keyword(s):  
Microwave Absorption ◽  
Carbon Nanofibers ◽  
Three Dimensional ◽  
Fish Bone ◽  
Absorption Properties ◽  
Simple Method ◽  
Microwave Absorption Properties ◽  
Absorption Performance ◽  
Microwave Absorption Performance ◽  
Better Than

AbstractIn this work, we demonstrated a simple method for preparing three-dimensional interconnected carbon nanofibers (ICNF) derived from fish bone as an efficient and lightweight microwave absorber. The as-obtained ICNF exhibits excellent microwave absorption performance with a maximum reflection loss of –59.2 dB at the filler content of 15 wt%. In addition, the effective absorption bandwidth can reach 4.96 GHz at the thickness of 2 mm. The outstanding microwave absorption properties can be mainly ascribed to its well-defined interconnected nanofibers architecture and the doping of nitrogen atoms, which are also better than most of the reported carbon-based absorbents. This work paves an attractive way for the design and fabrication of highly efficient and lightweight electromagnetic wave absorbers.

Solvent diffusion mechanism of PMMA/ acetone coated glass fiber fabric during curing process

2021 ◽  
pp. 152808372110362
Author(s):  
Zhenrong Zheng ◽  
Yuejiao Bi ◽  
Lihuan Tong ◽  
Yalan Liu
Keyword(s):  
Glass Fiber ◽  
Diffusion Mechanism ◽  
Coating Film ◽  
Curing Process ◽  
Curing Time ◽  
Solvent Concentration ◽  
Solvent Diffusion ◽  
Coated Glass ◽  
Drying Model ◽  
Fiber Fabric

Fabric it is not an impermeable substrate because of fiber porosity. To study the solvent diffusion mechanism of coated fabric in the curing process, the drying model of PMMA/acetone coated glass fiber fabric was established. This drying model was verified by confocal Raman spectroscopy. Finally, the impact of fabric structure, thickness and porosity on the solvent diffusion process in coated fabrics was studied by the model. It was shown that the predicted solvent concentrations by the model were consistent with the experimental values. This model can be used to quantitatively calculate the solvent concentration at any position and at any time inside the coating film during the drying process. Moreover, it can also predict the curing time and residual solvent concentration of the coating fabric required to reach drying equilibrium. Compared with coated 3/1 twill, 5/3 satin and 2/1 twill, the solvent diffusion of coated plain fabric was faster during curing. Under the same environmental conditions, the thinner the fabric was and the greater the porosity was, the shorter the curing time was. The fitting equations for fabric thickness, fabric porosity and drying time were obtained, which can provide a theoretical guidance for the preparation, performance research and drying conditions optimization of PMMA coated textile materials.

scholarly journals The value of a simple method to decrease diagnostic errors in Turner syndrome: a case report

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Seyedetahere Mousavi ◽  
Batool Amiri ◽  
Saidee Beigi ◽  
Mohammadreza Farzaneh
Keyword(s):  
Case Report ◽  
Standard Deviation ◽  
Physical Examination ◽  
Turner Syndrome ◽  
X Chromosome ◽  
Genetic Disorder ◽  
Diagnostic Errors ◽  
Height Velocity ◽  
Target Height ◽  
Simple Method

Abstract Introduction Turner syndrome is a genetic disorder in females and is the result of complete or partial loss of an X chromosome during fertilization. The missing X chromosome is originally either from the mother's ovum or the father's sperm cell. Approximately 45% of patients have the 45,X karyotype and the rest have other variants of Turner syndrome, which are either mosaicism patterns or structural abnormalities of the X chromosome. Here, we report a case of Turner syndrome that is the fifth case of Turner syndrome with balanced Robertsonian translocation of (13;14)(q10;q10), and the sixth case with 44,X chromosomes, reported in the literature thus far. Case presentation A 10.3-year-old Persian girl was brought to our clinic by her parents, with the complaint of failure to thrive and short height. She had been examined and investigated by endocrinologists since the age of 4 years, but no definite diagnosis was made. At the time of presentation, she had been through three provocative growth hormone tests and had been on no medications for about a year. Her physical examination revealed mild retrognathia and micrognathia. Initially, she was started on somatropin treatment which, after 12 months, did not appropriately improve her height velocity. Therefore, a more thorough physical examination was performed, in which high arched palate and low posterior hairline were observed. There was also a difference between target height and patient height standard deviation scores. Karyotype study was requested, and Turner syndrome was confirmed. Conclusion The diagnosis of this case was not straightforward, both because the somatic presentations were not obvious, and because the physicians had not looked for them when performing the physical examinations. This case report introduces a rare 44,X chromosome karyotype of Turner syndrome and highlights the value in using the difference between target height and patient height standard deviation scores as a simple and inexpensive tool for diagnosis of this syndrome.

Coating techniques for glass beads as filter media for removal of manganese from water

2016 ◽  
Vol 17 (1) ◽  
pp. 95-106 ◽  
Author(s):  
Peter Rose ◽  
Simon Hager ◽  
Karl Glas ◽  
Dirk Rehmann ◽  
Thomas Hofmann
Keyword(s):  
Manganese Oxides ◽  
Glass Beads ◽  
Stirred Tank ◽  
Continuous Stirred Tank Reactor ◽  
Filter Media ◽  
Dry Coating ◽  
Stirred Tank Reactor ◽  
Tank Reactor ◽  
Coated Glass ◽  
The Media

Dry as well as wet coating techniques were developed to coat glass beads as filter media to remove manganese from water. For dry coating, powdered manganese oxide ore was fixed on the media surface. Wet coating was achieved by depositing synthetic manganese oxides onto the bead surface. The media were characterized by electron microscopy as well as by testing the removal of Mn2+ in a continuous stirred tank reactor. Image analysis of microscopic pictures illustrated that the surface area could partly be coated by powdered material using dry coating methods, whereas complete coverage was achieved using wet coating approaches. With regard to dry coating techniques, Mn sorption uptake was higher for the adhesively dry coated glass beads than for beads where a binding agent was used. The wet coating column approach proved to be more successful than the coating of beads in a stirred tank reactor. Mn removal capability of the beads increased with higher reactant concentrations during coating. Oxide-coated glass beads applied in filter systems have the potential to improve conventional demanganization processes.

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