Maximum Permissible Research Articles

QoS-based adaptive power control scheme for co-located WBANs: a cooperative bargaining game theoretic perspective

This paper proposes a new Quality of Service (QoS)-based adaptive power control (QPC) scheme for interference mitigation among co-located wireless body area networks (WBANs). The problem can be formulated as a Nash bargaining game. The proposed solution not only achieves the Pareto optimal solution, but also guarantees the fairness among competing players. Owing to the special features of WBANs, the proposed utility function considers the urgency of the sensed data and the energy efficiency of sensors, which are indicated by emergency index and energy consumption factor, respectively. Thus, the transmission power is adjusted dynamically to adapt to the different QoS requirements under the constraints of permissible maximum transmission power and desired minimum signal-to-interference-plus-noise-ratio (SINR). Moreover, a unified analytical framework based on Lagrange multiplier approach is adopted to optimize the Nash product, where near optimal power control strategy is derived iteratively using the fix-point method. Extensive simulation results show that compared with the existing benchmark algorithms, the proposed QPC scheme has better performance in terms of energy efficiency, network reliability, Pareto optimality and fairness.

Cuantificación voltamétrica de carbofurano en papa (Solanum tuberosum L., Solanaceae)

<p>El exceso en la aplicación de plaguicidas puede<br />generar acumulaciones en los tubérculos de papa<br />que sobrepasen el límite máximo residual (LMR)<br />presentado por el Codex Alimentarius, lo cual<br />representa riesgos para la salud de los consumidores.<br />La cuantificación de plaguicidas es un proceso<br />costoso y de difícil acceso para los cultivadores y<br />entes de salud y de vigilancia. En este artículo se<br />presenta una metodología sencilla, económica y<br />asequible para la cuantificación de carbofurano en<br />tubérculos. El método de voltametría diferencial<br />de pulso (DPV) para carbofurano fue validado para<br />su cuantificación en papa. El estudio fue realizado<br />usando como electrolito de soporte la solución buffer<br />Britton-Robinson, un electrodo de trabajo de carbón<br />vítreo, Ag/AgCl como electrodo de referencia y<br />platino como electrodo auxiliar. El insecticida<br />en papa fue extraído por reparto sólido-líquido y<br />los resultados obtenidos fueron contrastados por<br />espectroscopía UV-Vis, lo cual permitió deducir que el<br />método voltamétrico genera resultados satisfactorios,<br />precisos y confiables para la cuantificación de carbofurano<br />en muestras de este tubérculo. Estos resultados<br />son una evidencia del uso de carbofurano en el<br />municipio de Ventaquemada (Boyacá). Este método<br />de detección de carbofurano puede utilizarse como<br />una herramienta para monitorear el uso de estos<br />compuestos químicos en la papa.</p>

BENZENE AND 1, 3 BUTADIENE CONCENTRATION AND ITS POTENTIAL HEALTH IMPACT IN CHIANG MAI, THAILAND

Air pollution is contamination of the outdoor or indoor environment by any physical, biological or chemical agent that modifies the natural characteristics of the atmosphere. Air pollution can cause long-term and short-term health effects. An emerging air pollution issue in Thailand is the air toxics problem resulting from transportation and industrial activities. Cancer risk of benzene at Chiang Mai City Hall was within 3.00x10 -6 – 1.20x10 -6 and Yupparaj Wittayalai School was within 9.30x10 -6 – 1.20x10 -5 respectively. The excess lifetime cancer risk of the population was calculated as the product of the benzene level and the unit risk for benzene. The results indicated that the population was estimated to receive an excess lifetime cancer risk greater than 1.0x10 -5 , which is proposed as the permissible maximum value for individual excess lifetime cancer risk by the Japan Environmental Agency (JEA). As for 1, 3-butadiene, cancer risk at Chiang Mai City Hall was within 3.00x10 -6 – 1.20x10 -6 and at Yupparaj Wittayalai School were 9.30x10 -6 – 1.20x10 -6 , respectively. The results indicated that the population was estimated to receive an excess lifetime cancer risk less than 1x10 -5 at two stations, which is proposed as the permissible maximum value by Japan Ministry of the Environment. Keywords: Benzene, 1, 3-butadiene, Cancer risk, Health impact

Assessment of heavy metals contamination in the Nile River water and adjacent sediments: A case study from Khartoum City and Nile River State, Sudan

The current study aims to investigate the heavy metals concentration and the degree of pollution in the water and adjacent sediment of the Nile River and its main tributaries at Khartoum City and River Nile State, Sudan. For this purpose, thirty-three water and sediment samples were collected from River Nile, Blue Nile, and White Nile. Water chemical properties and sediment physic о -chemical properties were measure. Concentrations of heavy metals (As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Ti, Zn) were determined for both sediment and water samples using inductively coupled plasma ( ICP-OES ). Enrichment factor (EF) and geo-accumulation index ( I geo ) were applied to quantify heavy metals pollution levels in sediment samples. The revealed that only Fe metal detected in the water samples and its concentrations within the permissible maximum limit. This indicated that water is highly suitable for irrigation. Depending on calculated enrichment factor (EF) and geo-accumulation index (Igeo), sediment samples were found to be enriched and polluted with Mn and Mo particularly at Berber site which may as consequence of gold mining activities in this area. The study revealed relatively strong to strong correlation between heavy metals of Co, Cr, Cu, Fe, Mn, Ni, Pb, Ti, Zn ( r2 =0.84 to 0.99) and significant negative correlation with Mo ( r2 =0.58 to 0.73) . This study recommends regular monitoring of heavy metals in the Nile River and its main tributaries for conservation and protection from pollution.

Modeling Remobilization of Neonicotinoid Residues from Tree Foliage in Streams-A Relevant Exposure Pathway in Risk Assessment?

Systemic neonicotinoid insecticides are increasingly used as a crop protection measure to suppress insect pests on trees. However, senescent foliage falling from treated trees represents a rarely studied pathway through which neonicotinoids may enter nontarget environments, e.g., surface waters. To estimate risk posed by this pathway, neonicotinoid residues were analyzed in foliage from black alder trees treated with one of three neonicotinoid insecticides (imidacloprid, thiacloprid, or acetamiprid) at five concentrations, each ranging from 0.0375-9.6 g active ingredient/cm trunk diameter at breast height (n = 3). Foliar residues measured at the time of leaf fall were used as input parameters for a model predicting imidacloprid water concentrations over a 100-m-long stream stretch as a consequence of remobilization from introduced foliage (input: 600 g foliage/m2 containing 80 μg imidacloprid/g). The water concentration (up to ∼250 ng/L) predicted by the model exceeded the recently proposed Maximum Permissible Concentration of 8.3 ng/L for ∼6.5 days. Moreover, dietary uptake was identified as an additional exposure route for aquatic organisms. The alternative pathway (i.e., introduction via leaf fall) and exposure route (i.e., dietary uptake) associated with the systemic nature of neonicotinoids should be accounted for during their registration process in order to safeguard ecosystem integrity.

USING INFORMATION TECHNOLOGIES FOR ESTIMATING THE WATER QUALITY IN THE EASTERN PART OF THE FINNISH GULF

The authors have developed a methodology of implementing of geoinformation technologies to assess the ecological situation in the waters of the eastern part of the Finnish Gulf and the Neva Bay, which is being formed under the influence of a complex system of interacting natural and anthropogenic processes. Spatial data base has been developed by using GIS technologies. Developed database is the backbone for the assessment of the water quality in the eastern part of the Finnish Gulf. The developed database of spatial information will be the main tool for accumulating, systematizing and analyzing the information about hydrochemical state of the waters of the eastern part of the Finnish Gulf and the Neva Bay. As the main indicators characterizing the ecological state of the waters of the eastern part of the Finnish Gulf, the Water Pollution Index (WPI) and E-TRIX eutrophication index have been used. The Water Pollution Index (WPI) is based on the values of the Maximum Permissible Concentration (MPC) of significant pollutants. The E-TRIX eutrophication index is an integrated complex indicator linking the characteristics of the potential level of the primary production of phytoplankton and concentration of nutrients necessary for the development of microalgae. Models of spatial distribution of the calculated values of pollution and eutrophication indicators allow for a preliminary assessment of the ecological situation in the Gulf waters and identify the main areas of pollution. Eutrophication and pollution of individual local areas have a different spatial distribution and differ significantly in pollutant elements. By the results of the work, it can be stated that the most unfavorable waters are the waters of the Neva Bay, which is determined by the anthropogenic load on the water area of the Neva Bay under a specific hydrophysical regime. The ecological state of the waters of the eastern part of the Gulf of Finland is more favorable, which can be explained by the low anthropogenic impact on the central part of the Gulf of Finland.

Wave Wash and Its Effects in Ship Design and Ship Operation: A Hydrodynamic Approach to Determine Maximum Permissible Speed in a Particular Shallow and Narrow Waterway

Wave wash is a hydrodynamic tool which explains ship generated waves and its impacts on shore and shore erosion. This paper describes that wave wash is an important factor to impose ship speed restriction and selecting speed for any shallow and narrow waterway. Relationships among ship speed, water depth, wave height, time period and wave energy have been established. Speed and depth conditions have been classified into four groups: Sub-Critical (Fh < 0.75), Trans-Critical (0.75 <Fh < 1.0), Critical (Fh = 1.0) and Super-Critical (Fh > 1.0). It is focused on waves generated by the ships to observe the maximum permissible speed for a vessel operated in a particular shallow and narrow water way. Empirical Formulae have been employed to find out maximum wave heights in relation with ship generated wave period, speed and other parameters. Maximum theoretical wave heights have been compared with wave wash criteria. These wave heights have also been compared with CFD results from potential flow solver and some commercial software. A case study has been done for a particular shallow and narrow waterway of Bangladesh. A vessel operated in that particular waterway had been selected for observing wave wash phenomena. Comparisons among theoretical results from different empirical equations, CFD results and different speed ranges have been done on which a model has been proposed to determine highest permissible ship speed in a shallow and narrow waterway. When a ship moves around critical speed range, wave wash becomes dominant.

Adaptive technology of environmentally - friendly production of legumes in the dry steppe zones

Modern agronomic technologies must include environmentally- friendly technologies in crop growing. In Kazakhstan, despite its significant potential, environmentallyfriendly farming is underdeveloped with little scientific backing. Therefore, the objectives of this study were to develop and suggest an adaptive technology for cultivation of legumes taking into account existing methodologies for environmentallyfriendly production in the dry steppe zone of Akmola region, Northern Kazakhstan. In order to achieve the objectives, the study focused on determination of a complex impact of combination of agroecological conditions (incl. agro- climatic, content of selected heavy metals such as Cu and Zn in soil, weed pressure, etc.), contrasting soil cultivation technology (i.e. traditional vs zero- tillage), nutrient inputs (fertilizers, legume stimulators) and pesticides on growth and productivity of selected legume crops (peas and chickpeas). The overall agroecological and growing conditions were suitable for producing economically- important legume crops (i.e. pea and chickpea), despite the temperature fluctiations and soil moisture shortage. Despite the very low content of N and P in the upper soil layer, the Cu and Zn content was within the Maximum Permissible Limits (MPL) for Kazakhstan, with a low anticipated negative effect on target legume growth. The least number of weeds was recorded by the variant with application of biological preparation Respecta. The targeted legumes were better developed during the growing season under the traditional technology compared to zero- tillage technology, i.e. germination and seed viability, which might be attributed to better utilisation of soil air and improved soil porosity of the soil layer of 0- 20 cm when using traditional technology. Combinations of mineral fertilizer CaSO4 + 2H2O5 with the innoculation promoter Rizotorfin, and Izagry Phosphorus with Rizotorfin may be recommended to farmers. The application of plant inoculation promoter Rizotorfin was more effective when combined with Phosphorus promoter Izagry Phosphorus. This combination i) reduced the time of passing the main phenophases of pea and chickpea, and the overall length of vegetation (in days). It gives farmers an opportunity to apply late sowing, e.g. in the beginning of June and use the higher temperatures during main vegetation period, and ii) had a positive impact on biological productivity of peas and chickpeas, i.e. an increase with percentage compared to control variant. The results have shown that seed inoculation with Rizotorfin (containg Rhizobium bacteria) and additional Phosphorus fertilizers would lead to significant increase of plant productivity, i.e. yield in the conditions of dry climate in Northern Kazakhstan.

Using Android Terminals for Measuring the Electric Field Strength Generated by Wi-Fi Access Points

In this article, some aspects related to the use of Android terminals for measuring the electric field strength generated by Wi-Fi wireless access points are provided. The main goal of this document is to determine if mobile phones can be used to measure electric field strength in a reliable way. This would make it possible for people to instantly know, anywhere and anytime, the level of non-ionizing radiation to which they are exposed. This level could be then compared to the limits for Maximum Permissible Exposure established by ICNIRP, in V/m units. Due to it is only possible to measure power levels using Android phones, a power-to-electric field conversion factor had to be found. For that, ten Android terminals and one calibrated isotropic meter were used. The results obtained clearly show the effect of the distance on the received electric field level. However, the application of the proposed methodology can introduce errors of up to 10 dB in the measurement of electric field strength.

Residue analysis of thyreostats in baby foods via matrix solid phase dispersion and liquid chromatography – dual-polarity electrospray – tandem mass spectrometry

ABSTRACTThis paper describes a rapid method for confirming residues of thyreostats in meat-based baby foods by using liquid chromatography – dual polarity electrospray – tandem mass spectrometry (LC-ES(±)-MS/MS). Six thioureylenes, belonging to the group of thiouracil and imidazole, were selected for this work: thiouracil (TU), methylthiouracil (MTU), propylthiouracil (PTU), phenylthiouracil (PhTU), mercaptobenzimidazole (MBI) and tapazole (TAP).The amphoteric nature of these compounds allows their electrospray detection in both positive and negative ionisation. Nevertheless, MS detection is not favoured by their low molecular weights, while their chromatographic retention is also thwarted by their high polarity. A pentafluorophenyl (PFP) core-shell phase column was selected to avoid peak asymmetry or peak splitting, and a dual-polarity ionisation method was optimised to obtain a sensitivity as high as possible. The method was validated according to the Commission Decision 657/2002/EC. A simple and fast procedure based on matrix solid phase dispersion (MSPD) was optimised to extract analytes from baby foods with recoveries exceeding 82%. Limit of decision (CCα) and detection capability (CCβ) were lower than the permissible maximum concentration (10 ng g−1). The validated method was then applied to assess the potential occurrence of the six selected thyreostats in nine commercial products. All the samples were found free of contamination.

Ozone-adsorption Method of TRIC and PERC Elimination from Underground Water Corresponding to the Russian Maximum Permissible Concentration Standards

ABSTRACTIn this research, the ozonation–sorption technology for water purification to remove trichloroethylene and tetrachloroethylene is presented. Physical and chemical (kinetic) parameters of consecutive ozonation and sorption of trichloroethylene and tetrachloroethylene from water are determined. The optimum technological parameters of this method for the purification of water from trichloroethylene and tetrachloroethylene are developed. R&D were carried out using water from 12 underground wells nearby Podolsk, Moscow region (Russia).

Contamination of soil and carrots irrigated with different sources of water in Punjab, Pakistan

High levels of heavy metals in the vegetables are seriously influencing the ecosystem as well as causing many health glitches. Due to many factors like, discharge of untreated industrial effluent, mine tailing, fertilizer application and irrigation with different water sources, the levels of heavy metals increased in soils which further transferred in biological systems. The present study was designed to access bioconcentration of Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, and Pb in soils and vegetables (carrots) irrigated with wastewater in Punjab, Pakistan. Result of the study showed that at both study sites concentrations of As and Cd were above the permissible maximum limits (PML). Similarly, concentrations of Mn, Ni, Mo, Cd, and Pb in the vegetable samples of both study sites were higher than maximum permissible limits. Overall, the accumulation of metals (Mn, Ni, Mo, Cd, and Pb) observed in carrots as well as in the soil was beyond the permissible limit that may cause human health disorders for their consumers.

Genotoxic Effect and Carcinogenic Potential of a Mixture of As and Cd in Zebrafish at Permissible Maximum Contamination Levels for Drinking Water

Currently, the toxic effects and carcinogenic potential of individually treated arsenic (As) or cadmium (Cd) are well documented both in animal and human tissues. However, there are no data focusing on the genotoxicity of these heavy metals as a mixture at the very low concentrations of permissible limits for drinking water. In this study, we examine the genotoxicity and carcinogenic potential of single and combined treatments of As and Cd, as well as attempt to elucidate the mechanism of action of certain cell defense systems such as antioxidants, gene repair, heat shock, cell cycle control, and the apoptosis pathway. Zebrafish (Danio rerio), reared under controlled conditions with artificial diets, were treated with As and Cd, either individually or in combination, at concentrations commonly found in water (10 ppb for As and 5 ppb for Cd) and tenfold higher concentrations for 48 h. Our results indicate that separately, As and Cd treatments at low dose selectively induce antioxidant enzymes, gene repair, and caspase-independent apoptosis in gill tissue, by targeting the mitochondria, leading to oxidative stress and sub-lethal levels of DNA damage. However, tenfold higher (100 ppb As + 50 ppb Cd) treatment caused significant downregulation of genes involved in double-strand break repair and molecular chaperone genes. Additionally, the highest BCL2/BAX ratio (1.6) and lowest expression levels of caspase-3 (8.4-fold) in all treated groups were observed in same condition. These results demonstrate that both single and combined exposure to As and Cd at permissible levels is potentially safe and causes repairable genotoxicity in gill tissue. However, the highest concentration is potentially carcinogenic due to ineffective DNA repair and insufficient apoptosis.

Simultaneous determination of cadmium, iron and tin in canned foods using high-resolution continuum source graphite furnace atomic absorption spectrometry

A method was established to simultaneously determine cadmium, iron and tin in canned-food samples using high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS). The quantification step has been performed using the primary line (228.802nm) for cadmium and the adjacent secondary lines (228.725nm and 228.668nm) for iron and tin, respectively. The selected chemical modifier was an acid solution that contained a mixture of 0.1% (w/v) Pd and 0.05% (w/v) Mg. The absorbance signals were measured based on the peak area using 3 pixels for cadmium and 5 pixels for iron and tin. Under these conditions, cadmium, iron and tin have been determined in canned-food samples using the external calibration technique based on aqueous standards, where the limits of quantification were 2.10ngg−1 for cadmium, 1.95mgkg−1 for iron and 3.00mgkg−1 for tin, and the characteristic masses were 1.0pg for cadmium, 0.9ng for iron and 1.1ng for tin. The precision was evaluated using two solutions of each metal ion, and the results, which were expressed as the relative standard deviation (RSD%), were 3.4–6.8%. The method accuracy for cadmium and iron was confirmed by analyzing a certified reference material of apple leaves (NIST 1515), which was supplied by NIST. However, for tin, the accuracy was confirmed by comparing the results of the proposed method and another analytical technique (inductively coupled plasma optical emission spectrometry). The proposed procedure was applied to determine cadmium, iron and tin in canned samples of peeled tomato and sardine. Eleven samples were analyzed, and the analyte concentrations were 3.57–62.9ngg−1, 2.68–31.48mgkg−1 and 4.06–122.0mgkg−1 for cadmium, iron and tin, respectively. In all analyzed samples, the cadmium and tin contents were lower than the permissible maximum levels for these metals in canned foods in the Brazilian legislation.

Influence of Stylus System Configuration on the Variability of Measurement Result on CMM

The article deals with the measurement on CMMs with tactile stylus system. Accuracy of CMM is mostly indicated by the parameter MPEE (Maximum Permissible Error for length measurement). This parameter refers to an errors during the measurement of distance between two points in space. Verification of MPEEparameter is described in an ISO standard 10 360-2 Acceptance and re-verication tests for coordinate measuring machines. These acceptance and re-verification tests are often conducted with a short and stiff reference stylus which is not and also mostly cannot be used in real measurements. On the contraryin applications such as a measurement of engine blocks and transmission housings very complex styli configurations are used. The influence of stylus system configuration on the variability of measurement when using long extensions, different materials (aluminium, carbon fiber composites) and high scanning speed in not described. The aim of this article is to design a methodology for testing the styli systems used in complex metrology applications in quality control of hi-precision mechanical components, to analyze the contribution of stylus system configuration to the measurement system variability in the form of a standard measurement uncertainty described by standard deviation.

Estimation of Sulphite Levels in Food Products Available in Delhi, India

Sulphites used as preservatives in foods might pose a risk for sensitive individuals, causing broncho-constriction, urticaria and dermatitis. The present work aimed at determining sulphite concentration using Optimized Monier- Williams method. A total of 357 food products were collected from different markets of Delhi and analysed for sulphites. The food products were classified into eight categories namely preserves, dried fruits, beverage concentrates, sugars, confectionery items, ready to serve beverages, bakery products and miscellaneous products. The mean recovery for 8 major food matrices was found to be 82.02% with relative standard deviation % RSDR of 3.22 and % RSDr of 1.72. The sulphite levels, expressed as sulphur dioxide, ranged from <10.0 mg/kg to 406 mg/kg. A total of 21% food products had sulphite concentration below the quantifiable limit of 10 mg/kg and in 30% of food products sulphites were not-detectable. Though most food samples presented sulphite levels below 50% of Maximum Permissible Level (MPL), a few local brands or un-branded samples of products like jam (n=1), sugar (n=3), fruit bars (n=3), digestives (n=1) and fruit beverages (n=1) had sulphite concentration 106% - 136% of the MPL. Beverages are likely to be major contributors to sulphite intake and brand loyal children are most likely to exceed their acceptable daily intake (ADI). Using the average concentration of sulphite obtained, 200 ml of beverage like squash will provide approximately 71% of the ADI for a child weighing 20 kg. Data generated can be utilized to estimate dietary exposure to sulphites and associated risk. Small scale manufacturers need to be sensitized about good manufacturing practices.

Distribution of Heavy Metals in Contaminated Water and Bottom Deposits of Manzala Lake, Egypt

The pollution of the El-Manzala lake bottom sediment is indicative of water and food-web quality in general. Twenty five samples were collected from both water and surficial bottom sediments. Collaborating analytical techniques have been employed to analyze group of environment-sensitive elements, including; Pb, Cd, Ni, Co, Cu, and Zn. The present study documents serious pollution by Cd, possibly as a result of using phosphate fertilizer. The average Cd content in the studied area is 17.5 ppm, which is about 36 fold the Maximum Permissible Limit (MPL=0.5 ppm) of soil. The highest concentration of Cd is 22.3 ppm, which is more than 45 fold the MPL. Cadmium is more mobile in aquatic environments than most other heavy metals. The areas around Port Said and El-Serw drain show marked pollution by most of the studied heavy metals. The main reason for such pollution is the industrial activities and agricultural drains. The unsupervised anthropogenic activities are the main causes of pollution in the studied lake. Routine program for monitoring the abundance and distribution of Cd, and Pb in the studied bottom lake sediments, water, biota and food chain should be imposed

A rapid inhibitive enzyme assay for monitoring heavy metals pollution in a river running through a UNESCO heritage site

The Malacca river runs through the Malacca UNESCO heritage site where a number of historical buildings are located. The river itself runs through several industrial sites that increase the chances of the water being polluted. Water pollution including heavy metals, in the long run, can damage the reputation of the site. Hence monitoring of the water quality needs to be done periodically. As the cost of instrumental monitoring is costly, biomonitoring using enzyme is being intensely developed worldwide. In this study, a rapid inhibitive enzyme assay using the molybdenum-reducing enzyme from the bacterium Serratia sp. strain DRY6 sensitive to the heavy metals mercury, copper, silver, and chromium was developed as a method for a rapid monitoring of heavy metals. The IC¬50 values for mercury, copper, silver and chromium were 0.268, 0.352, 0.393 and 0.499 mg L-1, while the LOD values were 0.166, 0.071, 0.033 and 0.064 mg L-1, respectively. The IC50 values for these heavy metals are comparable and in several cases, more sensitive than established assays. Water samples from various locations in the Melaka river were tested for the presence of heavy metals using the developed assay. Enzyme activity was found to be inhibited in one sampling location, but the concentration of metal ions on the site was found to be below the Maximum Permissible Limit according to Malaysian Environmental Quality standard. The assay for heavy metals can be completed in less than 10 minutes and can be carried out at ambient temperature. The assay is rapid and simple and can be used as a first screening method or even near real-time method for routine monitoring of heavy metals.

Use of tartaric acid–citric acid–sucrose as chemical modifier for the determination of lead in several matrices employing ET AAS

The present paper proposes the employ of a mixture containing sucrose–tartaric acid–citric acid as chemical modifier for the determination of lead using electrothermal atomization with atomic absorption spectrometry (ET AAS). The reagent concentrations in the modifier solution were established using a mixture design. Using the optimized conditions the pyrolysis and atomization temperatures established were 900 and 2000°C, respectively. So, the method allows the determination of lead with limits of detection and quantification of 0.14 and 0.46μgL−1, characteristic mass of 18pg and a precision expressed as relative standard deviation of 1.3%, 2.6% and 4.0% for lead solutions with concentrations of 10.0, 5.0 and 2.0μgL−1, respectively. The accuracy was confirmed by analysis of the following certified reference materials: NIST SRM 1515 (apple leaves), NIST SRM 1570a (trace elements in spinach leaves), NIST SRM 1643e (trace elements in water), CASS-4 (nearshore seawater) and BCR-713 effluent wastewater IRMM. The method proposed was applied for the determination of lead in surface water samples collected in the Paraguaçu River, Cachoeira City, Brazil in August 2015. Nine samples were analyzed and the lead content found varied from 0.64 to 8.25μgL−1, being always lower than the permissible maximum level stipulated by the Brazilian Ministry of Health, which is 10.0μgL−1.

Determination of Aspect Ratio Limitations, Accuracy and Repeatability of a Laser Line Scanning CMM Probe

Coordinate measurement machine (CMM) probing techniques can involve direct mechanical contact (e.g., tactile probing) or diverse non-contact principles (e.g., laser line scan probing). For some applications, contact methods are not capable of measuring fast enough to ensure 100% quality controlled parts. A laser line scanning probe uses a laser triangulation-based method to acquire 3D measurement points on a workpiece relative to a sensor. Mounting the sensor in a 3D coordinate frame, e.g., in a CMM provides enough information to fully examine the workpiece. These techniques are most commonly exploited in medical industry and industries involving plate materials. A high data density and measurement speed are significant advantages when measuring free-form surfaces by laser line scanning, making the process much more time-efficient. However, high-precision geometrical features (such as cylinders, spheres, etc.) must be measured for locating and aligning the free-form shapes. The accuracy of the equipment therefore has to be assessed. Probe Maximum Permissible Error (MPEP) values below 10μm have been reported for cutting-edge laser line scanners. This paper compares the major influences on measurements on cylindrical features. First, the aspect-ratio limitations are considered by comparing two inherently different techniques. The stable inspection of reference features is important, while trying to maximize the spatial extent of the measured features. Second, the measurement method is analyzed in two ways: by using a limited sample of the features to increase stability and eliminate interference from neighboring features; by varying the number of scan tracks, which greatly affects the measurement time.