Top PDF Determination of benzo(a)pyrene content in PM10 using regression methods

Determination of benzo(a)pyrene content in PM10 using regression methods

Determination of benzo(a)pyrene content in PM10 using regression methods

The standard PN-EN 15549:2008 „Air quality. Standard method for the measurement of the concentration of benzo(a)pyrene in ambient air” describes a reference method for determination of B(a) P concentration in suspended dust. The methodology engulfs sample extraction and analysis using high- performance liquid chromatography (HPLC) with luorescence detector (FLD). Conditioning of the ilters with trapped suspended dust PM10 upon deined temperature and humidity conditions for a given period of time as well as following B(a)P analysis extend the time of B(a)P concentration measurement. Laborious and time-consuming B(a)P measurements can be avoided via estimation of B(a)P concentration with a mathematical model allowing prediction of B(a)P concentration in suspended dust with a given probability. Such approach would be especially advantageous when PM10 and meteorological parameters are measured on- line. Then the value of these would be known in real time yielding almost immediate information about potential hazards for the society. When the reference method of B(a)P measurement is used, such information is often provided after the occurrence of episodic hazard. One of the simplest methods of B(a)P concentration prediction is multidimensional linear regression based on known PM10 dust concentration and known meteorological data such as: air temperature (T), wind velocity (v), wind direction (k), air humidity (ϕ) and intensity of solar radiation (I) [11-13]. This method would be especially useful in the case of signiicant anthropogenic human activity and could become the approach supplementary to the objective methods of estimation of B(a)P concentration levels in suspended dust, which are mentioned in the Regulation of the Ministry of Environment [14]. Performing analysis of multidimensional linear regression for meteorological
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Hot Resistance Estimation for Dry Type Transformer Using Multiple Variable Regression, Multiple Polynomial Regression and Soft Computing Techniques

Hot Resistance Estimation for Dry Type Transformer Using Multiple Variable Regression, Multiple Polynomial Regression and Soft Computing Techniques

Abstract: Problem statement: This study presents a novel method for the determination of average winding temperature rise of transformers under its predetermined field operating conditions. Rise in the winding temperature was determined from the estimated values of winding resistance during the heat run test conducted as per IEC standard. Approach: The estimation of hot resistance was modeled using Multiple Variable Regression (MVR), Multiple Polynomial Regression (MPR) and soft computing techniques such as Artificial Neural Network (ANN) and Adaptive Neuro Fuzzy Inference System (ANFIS). The modeled hot resistance will help to find the load losses at any load situation without using complicated measurement set up in transformers. Results: These techniques were applied for the hot resistance estimation for dry type transformer by using the input variables cold resistance, ambient temperature and temperature rise. The results are compared and they show a good agreement between measured and computed values. Conclusion: According to our experiments, the proposed methods are verified using experimental results, which have been obtained from temperature rise test performed on a 55 kVA dry-type transformer.
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Quím. Nova  vol.40 número9

Quím. Nova vol.40 número9

Biodiesel purity expressed as fatty esters content is one of its most important quality parameters. Although several instrumental methods have been employed, gas chromatography with internal standard calibration has been the most used. Biodiesel is a very complex matrix, therefore finding a suitable internal standard (IS) is not straightforward. EN14103:2003 standard established methyl heptadecanoate (C17:0) as IS. Since this fatty ester is naturally present in some biodiesel feedstock as tallow, that standard was reviewed in 2011, and methyl nonadecanoate (C19:0) became the new IS. In turn, C19:0 produces a peak on the chromatogram that is difficult to resolve from methyl linoeate (C18:2) and metyl linolenate (C18:3) ones. In this paper, a GC-FID method for the determination of the esters content in methyl and ethyl biodiesel from canola and soy oils, using hexadecyl acetate as a new internal standard was validated. EN14103:2003 was used as reference method. Method selectivity, accuracy (t student parameter < 2.18 from both methods), repeatability (0.1 - 0.4%), intermediate precision (0.2 – 1.8%), and robustness (0.1 – 1.6%) were investigated and considered appropriate for the scope.
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Determination Of Longevity Of Teeth In Buckets Of Loading Equipment In Coal Mines - A Case Study

Determination Of Longevity Of Teeth In Buckets Of Loading Equipment In Coal Mines - A Case Study

device was studied. The study took into account the effects of machine scale, wear surface structure of the rolls, grinding pressures and rolls speed, gap settings, feed size distribution and moisture content for a range of ores. The authors proposed a prevailing wear mechanism and a methodology for minimising wear of the grinding rolls, specific to the high pressure grinding device only. An example of a direct method, Bond (1964) and Buchi (1995) developed testing apparatus that determine rock abrasiveness in a low abrasion/medium impact mode of wear where rock abrasiveness is measured as the amount of material lost by a standard steel paddle which rotates on a shaft in a sample of loose rock particles of a certain specified size range. As can be seen from the above examples, the indirect methods of rock abrasivity assessment have the advantage of using data which is either readily available or relatively straightforward to obtain. However, they do not take into account process variables for specific modes of wear. Hence, they are normally not used in isolation, but rather in combination with direct methods, or holistic approaches, to supplement or confirm other more relevant direct measures. However, there is no universally accepted one standard test to determine the rock abrasivity although a large number of different tests are in use. All the studies about rock abrasiveness are concentrated on the amount of quartz, grain size and cementation degree of quartz, the geometry of the abrasive mineral and mechanical strength of rock.
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DETERMINATION OF BIODIESEL CONTENT IN DIESEL USING THE COLORIMETRIC ASSAY FOR HYDROXAMIC ACID.

DETERMINATION OF BIODIESEL CONTENT IN DIESEL USING THE COLORIMETRIC ASSAY FOR HYDROXAMIC ACID.

DETERMINATION OF BIODIESEL CONTENT IN DIESEL USING THE COLORIMETRIC ASSAY FOR HYDROXAMIC ACID. The aim of this paper was to use colorimetric assays for hydroxamic acid to quantify the biodiesel content in diesel and compare it with the traditional method (infrared spectroscopy, using the EN 14078 method). Samples were prepared from B2 to B10 with two kinds of diesel - S500 (red) and S50 (yellow) - to obtain two calibration curves. Through statistical methods it was shown that the slopes of the straight lines obtained for the different types of diesel were the same. Thus, the type of diesel did not influence the results of the colorimetric assay for hydroxamic acid. Real samples collected from gas stations were analyzed by both methods (colorimetry and EN 14078). By applying Student’s t-test it was concluded that the methods could be considered statistically equivalent. Therefore, it was confirmed that the colorimetric assay for hydroxamic acid is suitable for detecting and quantifying the content of biodiesel in biodiesel/diesel blends and can also be easily adapted to field analyses.
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Forms of organic phosphorus in wetland soils

Forms of organic phosphorus in wetland soils

The final group of wetlands (group D) represented those with a neutral to slightly alkaline pH (pH 7.0 to 7.6) and relatively low organic matter content (16 to 30 % loss on ignition). This group was dominated by calcareous fens (Macek and Rejmánková, 2007) situated near the coast of northern Belize (sites 17, 18 and 19), but also included an arctic tundra system (site 25) that has experienced heavy grazing by migrating pink-

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Methodologies to analyze the  alterations of enamel subjected to abrasionerosion

Methodologies to analyze the alterations of enamel subjected to abrasionerosion

Atomic Force Microscopy (AFM) and AFM Nanoindentation Recently, the application of atomic force microscopy (AFM), and especially AFM nanoindentation, in biological research has been conducted. AFM provides a powerful tool to investigate the surface morphology of a variety of biological samples with nanometer resolution. There are two types of AFM scanning: tapping mode and contact mode [47]. Tapping mode AFM has been successfully applied to study alterations in enamel. AFM is capable of delivering high- resolution images of tooth enamel and, thus, unlike mechanical profilometry, allows quantifying the enamel loss caused by erosion [35]. Figure 3 shows an enamel without erosive/abrasive challenges and Figure 4 shows the micromorphological alteration of enamel after seven days of erosion plus abrasion (immersion in Coke for 5 min, with immediate abrasion for 30 strokes, three times a day).
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J. Braz. Chem. Soc.  vol.23 número4

J. Braz. Chem. Soc. vol.23 número4

In this work, HPLC (called method B) and GC techniques are compared with respect to the determination of FAMEs in biodiesel. For this study, the main refined vegetable oils used in European Union, United Stated and Brazil were chosen: cotton, canola, sunflower, corn and soybean oils. Although the present study is limited to the investigation of these oils, it is possible to extend our method to other fats and oils if they have their composition based on similar fatty acids. For instance, despite olive and palm-tree oil have not been investigated, their composition usually contains up to 97% of the fatty acids here studied.
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Selection Of High Performing Geometry In Flexure Bearings For Linear Compressor Applications Using Fea.

Selection Of High Performing Geometry In Flexure Bearings For Linear Compressor Applications Using Fea.

Abstract: The word ―bearing‖ comes from the verb ―to bear‖, a bearing is thus a machine element that permits one part to bear another, by allowing relative motion between them. A bearing is a machine element that constrains relative motion and reduces friction between moving parts to only the desired motion or it is a mechanical element which locates two machine parts relative to each other and permits a relative motion between them. Bearings are components that are used to reduce the amount of friction in a machine. The present work reported in this paper is specific to the selection of a bestgeometry among the selected geometries for flexure bearing used in linear compressor. This paper proposes FEM as tool to find the equivalent stress.Selection of geometry is one of the most important steps in the process of design. The best geometry is one which will serve the desired objective like performance and service life at minimum cost. The main objective of this paper is to investigate best geometry of flexure spring to enhance its performance and improve upon the life of the flexure of service. Performance of the flexure, service life of the spring can be enhanced by achieving lower operating stresses and higher factor of safety.
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DETERMINATION OF THE KINETIC PARAMETERS OF BeO THERMOLUMINESCENT SAMPLES USING DIFFERENT METHODS

DETERMINATION OF THE KINETIC PARAMETERS OF BeO THERMOLUMINESCENT SAMPLES USING DIFFERENT METHODS

The field of thermoluminescent dosimetry is widely used in personal dosimetry, and year by year new compounds are studied as possible thermoluminescent materials with the objective of having a material more equivalent to biological tissue, and therefore it is necessary to know all the physical characteristics of the substance, as for example the kinetic parameters.

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Rev. bras. farmacogn.  vol.22 número5

Rev. bras. farmacogn. vol.22 número5

Taking lavonoid solubility into account, the alcohol percentage was varied from 0 to 100%. As illustrated in Figure 4, the lavonoids content was similar for both species at lower ethanol concentrations (0-25%). Between 50 and 75%, lavonoid extraction increased signiicantly when the ethanol proportion was increased for P. edulis, but remain practically unaltered for P. alata. Maximum lavonoid extraction was achieved with 75% ethanol for P. edulis. At this concentration, evaluation of the lavonoid content indicated that the P. edulis extract (9.14% w/w) contained twice the lavonoid content of P. alata (4.21% w/w). These results have been corroborated by Petry et al. (2001) and De Paris et al. (2002). On the other hand, a signiicant decrease in lavonoids extraction was observed when increasing to 100% ethanol for P. alata. P. edulis also displayed a signiicant diminution of lavonoids extraction. However, extraction from P. edulis was higher than P. alata at the same ethanol concentration.
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ESTIMATION METHODS OF REFERENCE EVAPOTRANSPIRATION (ETo) FOR UBERLÂNDIA -MG

ESTIMATION METHODS OF REFERENCE EVAPOTRANSPIRATION (ETo) FOR UBERLÂNDIA -MG

The coefficient of correlation (r) and the standard error of estimation (SEE) derived from comparison between estimated values of ETo by methods of HG, MK and RS with method PM showed that HG and MK with r, respectively, of 0.8389 and 0.8442, have positive correlation with method of PM, since variation amplitude of correlation is defined as - 1 ≤ r ≤ 1, and so the closer to the unit, the more effective is the correlation. The coefficient of correlation do not indicate any cause-effect relation between variables and that, only ETo estimated by standard-method PM tend to increase as ETo obtained by studied methods increase. Regarding SEE, method HG presented the smallest error, 0.58 mm d -1 , this indicates lowest deviation and best adjustment in relation to standard-method PM. Similar results were achieved in the basin of Jacupiranga river - SP, by BORGES & MENDIONDO (2007), in a study of comparison of estimation methods of ETo with standard-method PM, in which method HG presented the smallest standard-error of estimation.
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Braz. J. Pharm. Sci.  vol.51 número1

Braz. J. Pharm. Sci. vol.51 número1

Other than these official methods, a variety of techniques have been reported for the determination of DEC in pharmaceutical dosage forms, and include gas chromatography [GC] (Ramana, Raghuveer, Khadgapathi, 1986; Nene, Anjaneyalu, Rajagopalan, 1984; Pfaff, Gayral, Mahuzier, 1978; Joseph, Lawrence, 2001), high performance liquid chromatography [HPLC] (Mathew, Kalyanasundaram, 2001; Reddy et al., 2011; Krishna Vamsi et al., 2012), proton magnetic resonance [PMR] spectroscopy (El-Obeid, 1984, Jezzy et al., 1996), DC polarography analysis (Walash et al., 1985), ion selective electrode potentiometry (Campbell et al., 1980) and titrimetry (Abigail et al., 2011; Bhanumathi et al., 1981). However, many of the reported methods for DEC, particularly, the chromatographic methods are complex, requiring expensive instrumental set up and skilled operator which are not always found in laboratories of developing and under developed countries. Thus, the need for a simple, selective and low-cost method is obvious, especially for routine quality control analysis of pharmaceuticals containing DEC.
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Braz. J. Pharm. Sci.  vol.47 número2

Braz. J. Pharm. Sci. vol.47 número2

Determination of moisture content in freeze-dried solids is typically done by Karl Fischer (KF) titration, thermogravimetry (TG) or gas chromatography (GC) (Roggo et al., 2007; Blanco et al., 1997; Zhou et al., 2003). Nevertheless, these methods are all time-consuming, inva- sive and destructive. Moreover, the sample to be analyzed may suffer contamination if the measurement is not car- ried out under appropriate conditions (Zhou et al., 2003; Kamat et al., 1989; Zheng et al., 2008). An ideal method should perform fast, non-invasive and non-destructive measurements with minimal or no sample preparation. These characteristics ensure that an entire batch can be thoroughly examined without modifying the content of vials. Over the last twenty years, several reports have been published concerning the determination of moisture content of lyophilized products by scanning through the bottom of vials (Kamat et al., 1989; Zheng et al., 2008; Derksen et al., 1998; Stokvold et al., 2002). Nonetheless, these studies have focused on development of models for accurate and precise at-line determinations by means of conventional spectrometers.
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Validation of chromatographic methods: an experiment using HPLC and Green Chemistry in methylxanthines determination.

Validation of chromatographic methods: an experiment using HPLC and Green Chemistry in methylxanthines determination.

Nos estudos de seletividade do método, para cada amostra, foram preparadas duas curvas analíticas: uma com as soluções de trabalho mis- tas na faixa de concentração de 2 a 30 μg mL -1 [r]

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Quím. Nova  vol.38 número7

Quím. Nova vol.38 número7

The UV-Vis absorbance spectra were recorded on a HACH mo- del DR 3900 (Loveland, Colorado, USA) spectrophotometer with a 1.0 cm glass cell. The measurements of the pH were made with an EcoMet model P25 pH meter (Guro-gu, Seoul, Korea) equipped with a combined glass calomel electrode. The sizes of the Ag-NPs were characterized by the transmission electron microscopy (TEM) using a Zeiss transmission electron microscope (Jena, Germany) operated at an accelerating voltage of 80 kV. A PLS program for the calibration prediction and the experimental design was written in MATLAB according to the algorithm described by Martens and Nӕs 44 and the PLS routine of PLS Toolbox (Eigenvector, version 2.1).
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METHODS OF REDUCTION OF FREE PHENOL CONTENT IN PHENOLIC FOAM

METHODS OF REDUCTION OF FREE PHENOL CONTENT IN PHENOLIC FOAM

6. Aseeva P.M., Ushkov V.A., Bruyako M.G., Lomakin S.M. Kompozitsiya dlya polucheniya pe- nofenoplasta [Composition for the Generation of Phenolic Foam]. Author’s Certificate no. 872532, 1981. 7. Bruyako M.G. Effektivnye teploizolyatsionnye materialy na osnove modifitsirovannykh rezol’nykh penofenoplastov [Effective Thermal Insulation Materials Based on Modified Resol Phenolic Foam]. Moscow, 2009, 19 p.

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Estimating Energy Conservation Potential Of Local Metal Casting Units In Uganda Using Data Envelopment Analysis

Estimating Energy Conservation Potential Of Local Metal Casting Units In Uganda Using Data Envelopment Analysis

Energy inefficiencies in the Ugandan SME foundry units is attributed to the technology employed, poor operations and maintenance practices, and the poor quality scrap inputs. There is need for improvement of technology, which could give better yields and energy efficiencies. Foundry employees should get acquaintance with better operation and management practices which embrace efficient energy management. Comparing the inputs and outputs of the foundries understudy using the DEA method indicate that the energyimprovement potentialfor the SME metal casting units in Ugandais about 42%.Various energy conservation measures need to be applied in order to reduce energy use, as indicated in the previous study [18].The model also highlights DMU1 (foundry A) and DMU4 (foundry D) as the foundries that can be emulated by foundry E. This study could be extended to other energy intensive industries like the processing industries and also benchmark energy conservation practices used in the developed countries to enable the Ugandan industries increase their productivity and competitiveness.
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Vitamin B2 content determination in liver paste by using acid and acid-enzyme hydrolysis

Vitamin B2 content determination in liver paste by using acid and acid-enzyme hydrolysis

Za odre đivanje ukupnog sadržaja riboflavina u namirni- cama potrebno je primeniti niz postupaka. Po oficinalnim Association of Official Analytical Chemistry (AOAC) meto- dama 15 za izolovanje riboflavina iz proizvoda od žita treba primeniti samo kiselu hidrolizu na povišenoj temperaturi i pritisku. U daljem postupku, potrebno je primeniti pre čišća- vanje preko razli čitih aktivnih smola. Mnogi autori koriste principe AOAC metoda, prilago đavajući ih konkretnim uzorcima, tako što primenjuju razli čite kiseline, enzime, temperaturu, vreme izlaganja pojedinim reagensima, kao i na čine prečišćavanja analita 16−21 . Vitamin B 2 ima osobinu
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Classification of the financial sustainability of health insurance beneficiaries through data mining techniques

Classification of the financial sustainability of health insurance beneficiaries through data mining techniques

Advances in information technologies have led to the storage of large amounts of data by organizations. An analysis of this data through data mining techniques is important support for decision-making. This article aims to apply techniques for the classification of the beneficiaries of an operator of health insurance in Brazil, according to their financial sustainability, via their sociodemographic characteristics and their healthcare cost history. Beneficiaries with a loss ratio greater than 0.75 are considered unsustainable. The sample consists of 38875 beneficiaries, active between the years 2011 and 2013. The techniques used were logistic regression and classification trees. The performance of the models was compared to accuracy rates and receiver operating Characteristic curves (ROC curves), by determining the area under the curves (AUC). The results showed that most of the sample is composed of sustainable beneficiaries. The logistic regression model had a 68.43% accuracy rate with AUC of 0.7501, and the classification tree obtained 67.76% accuracy and an AUC of 0.6855. Age and the type of plan were the most important variables related to the profile of the beneficiaries in the classification. The highlights with regard to healthcare costs were annual spending on consultation and on dental insurance.
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