Limit Of Deviation Research Articles

Fluctuations of apparent entropy production in networks with hidden slow degrees of freedom

The fluctuation theorem for entropy production is a remarkable symmetry of the distribution of produced entropy that holds universally in non-equilibrium steady states with Markovian dynamics. However, in systems with slow degrees of freedom that are hidden from the observer, it is not possible to infer the amount of produced entropy exactly. Previous work suggested that a relation similar to the fluctuation theorem may hold at least approximately for such systems if one considers an apparent entropy production. By extending the notion of apparent entropy production to discrete bipartite systems, we investigate which criteria have to be met for such a modified fluctuation theorem to hold in the large deviation limit. We use asymptotic approximations of the large deviation function to show that the probabilities of extreme events of apparent entropy production always obey a modified fluctuation theorem and, moreover, that it is possible to infer otherwise hidden properties. For the paradigmatic case of two coupled colloidal particles on rings the rate function of the apparent entropy production is calculated to illustrate this asymptotic behavior and to show that the modified fluctuation theorem observed experimentally for short observation times does not persist in the long time limit.

Packing Fraction of a Two-dimensional Eden Model with Random-Sized Particles

We have performed a numerical simulation of a two-dimensional Eden model with random-size particles. In the present model, the particle radii are generated from a Gaussian distribution with mean $\mu$ and standard deviation $\sigma$. First, we have examined the bulk packing fraction for the Eden cluster and investigated the effects of the standard deviation and the total number of particles $N_{\mathrm{T}}$. We show that the bulk packing fraction depends on the number of particles and the standard deviation. In particular, for the dependence on the standard deviation, we have determined the asymptotic value of the bulk packing fraction in the limit of the dimensionless standard deviation. This value is larger than the packing fraction obtained in a previous study of the Eden model with uniform-size particles. Secondly, we have investigated the packing fraction of the entire Eden cluster including the effect of the interface fluctuation. We find that the entire packing fraction depends on the number of particles while it is independent of the standard deviation, in contrast to the bulk packing fraction. In a similar way to the bulk packing fraction, we have obtained the asymptotic value of the entire packing fraction in the limit $N_{\mathrm{T}} \to \infty$. The obtained value of the entire packing fraction is smaller than that of the bulk value. This fact suggests that the interface fluctuation of the Eden cluster influences the packing fraction.

Monitoring of selected skin- and breath-borne volatile organic compounds emitted from the human body using gas chromatography ion mobility spectrometry (GC-IMS)

Human smuggling and associated cross-border crimes have evolved as a major challenge for the European Union in recent years. Of particular concern is the increasing trend of smuggling migrants hidden inside shipping containers or trucks. Therefore, there is a growing demand for portable security devices for the non-intrusive and rapid monitoring of containers to detect people hiding inside. In this context, chemical analysis of volatiles organic compounds (VOCs) emitted from the human body is proposed as a locating tool. In the present study, an in-house made ion mobility spectrometer coupled with gas chromatography (GC-IMS) was used to monitor the volatile moieties released from the human body under conditions that mimic entrapment. A total of 17 omnipresent volatile compounds were identified and quantified from 35 ion mobility peaks corresponding to human presence. These are 7 aldehydes (acrolein, 2-methylpropanal, 3-methylbutanal, 2-ethacrolein, n-hexanal, n-heptanal, benzaldehyde), 3 ketones (acetone, 2-pentanone, 4-methyl-2-pentanone), 5 esters (ethyl formate, ethyl propionate, vinyl butyrate, butyl acetate, ethyl isovalerate), one alcohol (2-methyl-1-propanol) and one organic acid (acetic acid). The limits of detection (0.05–7.2 ppb) and relative standard deviations (0.6–11%) should be sufficient for detecting these markers of human presence in field conditions. This study shows that GC-IMS can be used as a portable field detector of hidden or entrapped people.

Ionic Liquid Based Ultrasound-Assisted Emulsification Microextraction for Preconcentration of Phenol Using Central Composite Design

In this work, phenol reacted with 4-aminoantipyrine (4-AAP) reagent in presence of potassium hexacyanoferrate(III) and then was extracted using ultrasound-assisted emulsification microextraction via 1-hexyl-3-methyl imidazolium hexafluorophosphate as an environmentally friendly solvent. Effects of the main experimental variables were investigated and optimized by central composite design. Under the optimum conditions (pH 9.5, 100 mg/L 4-AAP, 100 μL of ionic liquid as extraction solvent, 0.2 g/L K3Fe(CN)6 and 0.2 M NH4Cl) the dynamic linear range, limit of detection and relative standard deviation were obtained as 0.2‒25 μg/L, 0.07 μg/L and 2.6%, respectively. Finally, the applicability of the proposed ultrasoundassisted emulsification microextraction was examined and very good results were obtained. The results confirmed the applicability of the proposed method as a versatile, low cost and sensitive preconcentration method for determination of very low concentrations of phenol in aqueous solutions.

Optimization of various parameters for the performance enhancement of PEM Fuel Cell

Objectives: In this paper, the experimental analysis of various parameters on 25 cm2 interdigitated flow channel have been used for performance enhancement of Polymer Electrolyte Membrane (PEM) fuel cellby optimization technique. Methods/ Statistical Analysis: The design parameter like Landing to Channel width ratio-(L:C) and two operating parameters like back pressure and cell temperature have been considered. Here, Taguchi technique and analysis of variance methodology (ANOVA) have been used to obtain the optimum combination for the above three parameters. Three factors and three levels, such as design parameter as ( L:C- 1:1, 2:2 and 1:2) and operating parameters as cell temperature like 40, 50 and 60o C and back pressure 0, 0.5 and 1 bar have been taken for optimization studies. Findings: This study has revealed that the selected parameters 1 bar for back pressure, 60°C of cell temperature and landing to channel width ratio of 1:2 yield the maximum power density 0.265 W/cm2 for interdigitated flow field. Also, multiple regression analysis studies have been carried out, and the regression co-efficient obtainable is 94.7% for inter-digitized flow fields with allowable maximum deviation limit is 5.3%. The maximum deviation of 1.156% has been occurred between the experimental data and regression model analysis. Also, the F and P tests carried out in this study indicated that the back pressure is having major impact on performance of the PEM fuel cell. The back pressure is contributing 81.8% for overall cell performance followed by L:C and cell temperatures has 13.50% and 0.80% respectively. Keywords: Design Parameter, Optimization, PEM Fuel Cell, Operating Parameter, Taguchi Technique, ANOVA

A Simplified Mathematical Model for Calculating the Thermal Efficiency of a Wood Pellets-Fired Industrial Boiler on the Basis of Error Analysis Method

The traditional calculation method of industrial boiler thermal efficiency needs to input many parameters, which leads to a lot of complicated calculations. It is not suitable to make an accurate judgement on the operating condition of an industrial boiler, especially a wood pellets-fired one. In order to solve this problem, the paper presents a simplified mathematical model to calculate the thermal efficiency of a wood pellets-fired industrial boiler on-line by using an error analysis method. More concretely speaking, first, based on the results of the error analysis of an industrial boiler thermal efficiency, main factors that affect the thermal efficiency of a wood pellets-fired industrial boiler are obtained. Then, a simplified mathematical model to calculate the thermal efficiency of the wood pellets-fired industrial boiler is developed in terms of the major factors. Finally, the calculating results of the industrial boiler thermal efficiency based on the model are compared with the test values given by Guangdong Special Equipment Inspection and Research Institute and the maximum deviation limits within 3%. Therefore, it can be concluded that the simplified mathematical model proposed in this paper for calculating the thermal efficiency of the wood pellets-fired industrial boiler is proved to be practical, applicable and worth popularizing.

QCM-D surpassing clinical standard for the dose administration of new oral anticoagulant in the patient of coagulation disorders

The study focuses the dose administration of dabigatran to avoid the deaths due to hemorrhagic complications and thromboembolic stroke in clinics worldwide. To target the issue, a novel emerging acoustic technology, namely ''Quartz Crystal Microbalance with Dissipation'' (QCM-D) has been applied, while the acoustic assays namely ''activated Partial Thromboplastin Time'' (aPTT) and ''Prothrombinase complex-induced Clotting Test'' (PiCT) have been compared with the standard methods in parallel. Both techniques have been applied to 300 samples, including 220 plasma samples of patients suffering coagulation disorders and 80 plasma samples of non-patients. In comparison, the coagulation times of the acoustic aPTT and PiCT yielded an excellent correlation with the standard methods with in analytical standard deviation limits. Finally, the acoustic aPTT assay is the ''gold standard'' for a dose administration of the new oral anticoagulant, where the Δf/ΔΓ ratio of the acoustic assay demonstrates that dabigatran with FEIBA 50 combination could be a safe remedy to avoid the deaths in clinics.

Optimization of solid phase dispersive field‐assisted ultrasonication for the extraction of auramine O and crystal violet dyes using central composite design

Simultaneous preconcentration and determination of auramine o (AO) and crystal violet (CV) dyes from aqueous solution was conducted by ultrasound assisted (dispersive) solid phase microextraction (UASPME) based on SnO2/SnS composite loaded activated carbon (SnO2/SnS‐NCs‐AC). The prepared of SnO2/SnS‐NCs‐AC was characterized by FESEM and XRD analysis. Main and interaction influences of operational parameters such as pH, sonication time, amounts of sorbent, and type of eluent on extraction efficiency were investigated by central composite design and optimized with desirability function approach (DFA). ANOVA was conducted and shows that optimized values were found at 15.33 min sonication time, 0.019 g SnO2/SnS‐NCs‐AC mass, pH 5.46 and among different solvents, dimethyl formamide was selected as an efficient eluent. Under this conditions recoverees percentage were obtained 82.85% and 86.70% for AO and CV, respectively. Based on F‐test under ANOVA all main effect and interaction effect of understudy parameters has the significant effect on the responses. At optimum conditions, limit of detection (0.0015 and 0.001 mg/l), limit of quantitation (0.4 and 0.4 mg/l), limit of linearity (9.0 and 9.0 mg/l), enrichment factor (33.48 and 83.71) and percent relative standard deviation (3.44 and 4.20) were found to be for auramine o and crystal violet dyes, respectively. Finally, the method was successfully applied for the preconcentration and determination of AO and CV in water samples and ER% of 89.0‐97.0 and 96.2–98.0% as acceptable range were found to be for AO and CV samples, respectively.

Assessment of interrater and intermethod agreement in the kinesiology literature

ABSTRACTThe purpose of this article was two-fold (1) provide an overview of the commonly reported and under-reported absolute agreement indices in the kinesiology literature for continuous data; and (2) present examples of these indices for hypothetical data along with recommendations for future use. It is recommended that three types of information be reported as evidence for agreement because no one type is superior to another. Report one graphical display (bivariate plot of raw scores with identity line or Bland-Altman plot), one scaled index (intraclass correlation coefficient with agreement definition or Lin’s Concordance Correlation Coefficient), and at least one unscaled index (root mean squared deviation, total deviation index, coverage probability, or limits of agreement) when there are two methods/raters with no replication. The amount of information recommended exceeds what has commonly been reported in absolute agreement studies published in the kinesiology literature.

Development of a dispersive liquid–liquid microextraction (DLLME) method coupled with GC/MS as a simple and valid method for simultaneous determination of phthalate metabolites in plasma

ABSTRACTPhthalates are ubiquitous environmental contaminants, and frequent biological monitoring of their metabolites (as toxic species of phthalates in human body) is highly recommended. A novel dispersive liquid–liquid microextraction (DLLME) coupled with Gas Chromatography–Mass Spectrometry (GC-MS) has been developed for the determination of seven phthalate metabolites in human plasma for the first time. Plasma proteins were efficiently precipitated by adding of 0.2mg dry trichloroacetic acid to 10 mL plasma samples, incubation and centrifuging. For DLLME, a mixture of extraction solvent (chlorobenzene, 10 µL) and dispersive solvent (acetonitrile, 750 µL) were rapidly injected into 5.0 mL aqueous sample for the formation of cloudy solution, the analytes in the sample were extracted into the fine droplets of chlorobenzene. After extraction, phase separation was performed by centrifugation and the enriched analytes in the sedimented phase were subjected to GC-MS analysis. All important parameters affecting DLLME performance were investigated and optimised. Under the optimum extraction condition, the method yields a linear calibration curve for all target analytes in the concentration range from 5 to 5000 ng mL−1. The limits of detection and relative standard deviations for all phthalate metabolites were between 1.21–2.09 ng mL−1 and 4.8–6.8%, respectively. This is a very simple, rapid and reproducible method, which requires low volume of sample and toxic solvents.

Determination of trace amounts of Co(II) after preconcentration with surface ion imprinted sorbent based on activated carbon

ABSTRACTIn this study, by using surface ion imprinting technique, Co(II)-imprinted activated carbon was synthesized as a new sorbent in order to use in solid phase extraction method. Several parameters were investigated and optimum experimental conditions were determined. Synthesized sorbent was characterized by Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Thermogravimetric Analysis and Brunaer, Emmet, and Teller techniques. The maximum adsorption capacity of imprinted and nonimprinted sorbents were found as 833.3 mg/g and 188.7 mg/g respectively. The limit of detection, the limit of quantification and relative standart deviation were found as 0.066 µg/L, 5.91 µg/L and 5.65% respectively.

Novel ultrasonic‐assisted deep eutectic solvent‐based dispersive liquid–liquid microextraction for determination of vanadium in food samples by electrothermal atomic absorption spectrometry: A multivariate study

A green, efficient, simple and sensitive pre‐concentration method has been developed for the determination of vanadium(V) in foodstuffs using deep eutectic solvent–ultrasonic‐assisted dispersive liquid–liquid microextraction. In the developed procedure, the extraction of vanadium(V) was achieved using 2‐hydroxy‐3‐methoxybenzaldehyde thiosemicarbazone as a chelating agent, choline chloride–phenol as extracting solvent and tetrahydrofuran as dispersive solvent. Vanadium(V) concentration was measured using electrothermal atomic absorption spectrometry. Various analytical parameters including pH, type and molar ratio of deep eutectic solvent, ultrasonication time and amount of ligand were studied. A multivariate study was carried out for optimization of the variables. The pre‐concentration factor was calculated as 50. Under optimal conditions, limit of detection, limit of quantification and relative standard deviation were calculated as 0.025 μg l−1, 0.175 μg l−1 and 3.4%, respectively. The accuracy of the procedure was confirmed using certified reference materials and standard addition method. The obtained results confirm adequate recoveries for vanadium(V) (>96%). This technique was fruitfully applied for determination of vanadium in foodstuffs.

Application of a dispersive micro‐solid‐phase extraction method for pre‐concentration and ultra‐trace determination of cadmium ions in water and biological samples

A method for the trace determination of cadmium ions in water, human urine and human blood serum samples using ultrasonic‐assisted dispersive micro‐solid‐phase extraction (UA‐D‐μSPE) was developed. Silica‐coated magnetic nanoparticles were coated with polythiophene, and the resulting sorbent was characterized using thermogravimetry, differential thermal analysis, scanning electron microscopy, Fourier transform infrared spectrometry and X‐ray diffraction. Following UA‐D‐μSPE, cadmium ions were quantified using graphite furnace atomic absorption spectrometry. A Box–Behnken design was used for optimization of important sorption and desorption parameters in UA‐D‐μSPE: in the sorption step, pH of solution, sorption amount and sonication time for sorption; in the desorption step, concentration of eluent, volume of eluent and sonication time. The optimum conditions for the method were: pH of solution, 7.5; sonication time for sorption, 3 min; sorption amount, 35 mg; type and concentration of eluent, HCl and 1.1 mol l−1; volume of eluent, 360 μl; sonication time for desorption, 110 s. Under the optimized conditions the limit of detection and relative standard deviation for the detection of cadmium ions by UA‐D‐μSPE were found to be 0.8 ng l−1 and <6%, respectively.

A new method for determination of cocamidopropyl betaine synthesized from coconut oil through spectral shift of Eriochrome Black T

Cocamidopropyl betaine (CAPB) is a zwitterionic surfactant that is synthesized using coconut oil and usually supplied in form of an aqueous solution with 25–37% w/w. In this study, a novel method based on UV–visible spectroscopy is developed for an accurate determination of CAPB synthesized from coconut oil. Eriochrome Black T (EBT) as a specific color indicator was added to CAPB and a red shift and color change were observed. This shift leads in increasing wavelength selectivity of the method. The change in the color intensity depends on the concentration of CAPB. By measuring the absorbance of a solution containing CAPB, its concentration was measured. After optimizing all the effective parameters, CAPB was detected in commercial real samples. Using the proposed approach, limit of quantification (LOQ) and relative standard deviation (RSD) were obtained about 4.30×10−5M and 4.8% respectively. None of unreacted materials or by-products, which were produced in the synthesis of CAPB, showed any interference in the determination of CAPB. This shows that the proposed method is specific and accurate, and can potentially be used for quantitative determination of CAPB in commercial samples with satisfactory results.

Petroleum Hydrocarbon Profiles of Water and Sediment of Algoa Bay, Eastern Cape, South Africa.

Petroleum hydrocarbon profiles of water and sediment samples of Algoa Bay in the Eastern Cape Province of South Africa were assessed using standard analytical procedures. Water (from surface and bottom levels) and sediment samples were collected from five locations in the bay from February to June 2016. Extraction of the petroleum hydrocarbons from the water and sediment samples collected was achieved using liquid-liquid and Soxhlet extraction techniques, respectively, followed by column clean up. Target compounds were analytically determined with gas chromatography–flame ionization detector (GC-FID) and quantified by integrating the areas of both the resolved and unresolved components. Physicochemical properties of the water samples were also determined on site using a SeaBird 19plusV2 CTD SBE 55 device. Estimated limit of detection, limit of quantitation and relative standard deviation for the 35 n-alkane standards ranged from 0.06 to 0.13 μg/L, 0.30 to 0.69 μg/L and 3.61 to 8.32%, respectively. Results showed that total petroleum hydrocarbon (TPH) varied from 45.07 to 307 μg/L in the water and 0.72 to 27.03 mg/kg in the sediments. The mean concentrations of TPH in both the water and sediment samples from Algoa Bay revealed a slight level of pollution. The diagnostic indices used showed that the hydrocarbons in the area were from both biogenic and anthropogenic sources. Hence, there is need for adequate regulation and control of all activities contributing to the levels of petroleum hydrocarbon in the marine environment for the safety of human, aquatic and wild lives in the area.

Multivariate statistical design optimization for ultrasonic-assisted restricted access supramolecular solvent-based liquid phase microextraction of quercetin in food samples

In this method, quercetin as a flavonoid has been extracted, preconcentrated and determined by using ultrasonic-assisted restricted access supramolecular solvent-based liquid phase microextraction method in food samples. The quercetin concentration in extraction phase was determinated by UV–visible spectrophotometer which has microsampling cuvette. Multivariate statistical design approach was used to optimize the analytical variables including the pH, ratio of restricted access solvent components, volume of restricted access solvent, ultrasonication and centrifugation times. The analytical performance values of the developed method including limit of detection, limit of quantification, preconcentration factor and relative standard deviation (10 replicates of 10–5 M of quercetin solution) were found as 2.98, 9.93 μg L−1, 30 and 6.3%, respectively. The method provides important advantages such as use of minimum volume of organic solvents, simple and economical operation and easy optimization via multivariate statistical design approach. The developed procedure was validated with four food samples, and acceptable recoveries (87–104%) were achieved.

Ultrasound assisted deep eutectic solvent based on dispersive liquid liquid microextraction of arsenic speciation in water and environmental samples by electrothermal atomic absorption spectrometry

A green and highly efficient deep eutectic solvent ultrasound-assisted liquid phase microextraction (DES-UALPME) method have been developed for speciation of As(III) and As(V). Extraction of As(III) was observed by using sodium diethyldithiocarbamate (DDTC) as a chelating agent, choline chloride-phenol as extracting solvent and tetrahydrofuran (THF) as dispersive solvent. Arsenic concentration was determined by electrothermal atomic absorption spectrometry (ETAAS). The developed procedure established on significant recoveries of As(III) and also As(V) recoveries were obtained as <5%. Whereas the reduction of As(V) was achieved with potassium iodide and ascorbic acid. This technique was useful for the analysis of total arsenic. Whereas As(V) was originated as variation among total As and As(III) levels. The key factors affecting the microextraction efficiency including pH, ultrasonication time, and amount of ligand were studied and optimized. Under optimum conditions, limit of detection (LOD), limit of quantification (LOQ), preconcentration factor (PF) and relative standard deviation (RSD) were calculated as 10ng L−1, 33ng L−1, 25 and 4.3%, respectively. The accuracy of developed technique was carried through the analysis of certified reference materials. Technique was used for the speciation of As(III) and As(V) in water samples collected from Tokat, Turkey. It was also applied for the determination of total arsenic within food and environmental samples.

SAMPLE STANDARD DEVIATION(s) CHART UNDER THE ASSUMPTION OF MODERATENESS AND ITS PERFORMANCE ANALYSIS

Moderate distribution proposed by Naik V.D and Desai J.M., is a sound alternative of normal distribution, which has mean and mean deviation as pivotal parameters and which has properties similar to normal distribution. Mean deviation (δ) is a very good alternative of standard deviation (σ) as mean deviation is considered to be the most intuitively and rationally defined measure of dispersion. This fact can be very useful in the field of quality control to construct the control limits of the control charts. On the basis of this fact Naik V.D. and Tailor K.S. have proposed 3δ control limits. In 3δ control limits, the upper and lower control limits are set at 3δ distance from the central line where δ is the mean deviation of sampling distribution of the statistic being used for constructing the control chart. In this paper assuming that the underlying distribution of the variable of interest follows moderate distribution proposed by Naik V.D and Desai J.M, 3δ control limits of sample standard deviation(s) chart are derived. Also the performance analysis of the control chart is carried out with the help of OC curve analysis and ARL curve analysis.

One step hydrothermal synthesis and characterization of moss like MWCNT-Bi2S3 nanomaterial for solid phase extraction of copper

The present work was designed with the aim to one step simple hydrothermal synthesis of moss like MWCNT-Bi2S3 nanomaterial as solid phase extraction sorbent for separation, preconcentration and determination of copper in tobacco and food samples. Cu(II) ions was strongly retained on the MWCNT-Bi2S3 nanomaterial at the pH 7.0 and was successfully desorbed by using 1.5mL of 4M HNO3. The copper concentration in eluent was determined by flame atomic absorption spectrometer. The certified reference material (NC SZC 73033 Scallion) was analyzed for the verification and accuracy of the proposed method. This work was interpreted statistically and found the analytical performance of the proposed method which consist of preconcentration factor (20), limit of quantification (13.1µgL−1) and relative standard deviation (2.2%), respectively. It was concluded that this method was applied for the detection of copper from different types of tobacco and food samples successfully.

Online monitoring of gold nanoparticles and induced aggregation by photothermal lens microscopy

ABSTRACTIn this paper, we have developed inverted photothermal lens microscopy (PTLM) with a flow through optical cell for online detection of gold nanoparticles (AuNPs) to monitor the AuNP production process and aggregation. The indirect detection of the plasmonic signals of AuNPs was performed using the thermal lens phenomena. The measurements were made using continuous-wave excitation (532 nm) and probe laser beams (652 nm). The changes of the transmitted probe beam’s intensity were detected with a photodiode. The results show the possibility of online determination of AuNPs in micro and nanovolumes in the range of 1.7–13.7 particles for the focal volume of the excitation beam. The obtained limit of detection and relative standard deviation for 10 repeated measurements of AuNPs were 0.65 nM and 1.43%, respectively. Therefore, this system was successfully applied for screening of aggregation in process applications.