Flow Analysis Approach Research Articles

A LED based photometer for solid phase photometry: zinc determination in pharmaceutical preparation employing a multicommuted flow analysis approach

Neste trabalho e proposto um fotometro baseado em LED (diodo emissor de luz) para fotometria em fase solida. O fotometro foi desenvolvido para permitir o acoplamento da fonte de radiacao (LED) e do fotodetector direto na cela de fluxo, tendo um caminho optico de 4 mm. A cela de fluxo foi preenchida com material solido (C 18 ), o qual foi utilizado para imobilizar o reagente cromogenico 1-(2-tiazolilazo)-2-naftol (TAN). A exatidao foi avaliada empregando dados obtidos atraves da tecnica ICP OES (espectrometria de emissao por plasma indutivamente acoplado). Aplicando-se o teste-t pareado nao foi observada diferenca significativa em nivel de confianca de 95%. Outros parâmetros importantes encontrados foram faixa de resposta linear de 0,05 a 0,85 mg L -1 Zn, limite de deteccao de 9 µg L -1 Zn (n = 3), desvio padrao de 1,4 % (n = 10), frequencia de amostragem de 36 determinacoes por h, e uma geracao de efluente e consumo de reagente de 1,7 mL e 0,03 µg por determinacao, respectivamente. In this work, a LED (light emitting diode) based photometer for solid phase photometry is described. The photometer was designed to permit direct coupling of a light source (LED) and a photodiode to a flow cell with an optical pathlength of 4 mm. The flow cell was filled with adsorbing solid phase material (C 18 ), which was used to immobilize the chromogenic reagent 1-(2-thiazolylazo)-2-naphthol (TAN). Aiming to allow accuracy assessment, samples were also analyzed employing ICP OES (inductively coupled plasma optical emission spectrometry) methodology. Applying the paired t-test at the 95% confidence level, no significant difference was observed. Other useful features were also achieved: linear response ranging from 0.05 to 0.85 mg L -1 Zn, limit of detection of 9 µg L -1 Zn (3σ criterion), standard deviation of 1.4% (n = 10), sampling throughput of 36 determinations per h, and a waste generation and reagent consumption of 1.7 mL and of 0.03 µg per determination, respectively.

Taint Propagation Analysis and Dynamic Verification with Information Flow Policy

In this paper,based on a flow and context-sensitive SSA(static single assignment) information-flow analysis,a fine-grained and scalable approach is proposed for taint propagation analysis,which can not only track tainted data and its propagation path with control and data-flow properties,but also detect the vulnerabilities such as buffer overflow and format string bugs successfully.During the analysis,pieces of code considered vulnerable are instrumented with dynamic verification routines,so that runtime security is guaranteed in the absence of user intervention.The analysis system is implemented as an extension of GCC compiler,and the experiments have proven that this approach is efficient,holding both optimized accuracy and time-space cost.

Turbidimetric determination of sulfate in rainwater employing a LED based photometer and multicommuted flow analysis system with in-line preconcentration

In the present work, an automatic procedure for turbidimetric determination of sulfate in rainwater, based on the multicommuted flow analysis approach, is proposed. The photometer set-up was developed at the laboratory, and includes: a LED (λ = 420 nm), a long pathlength flow cell (100 mm), and a photodiode. A preconcentration step is included in order to improve sensitivity. After establishing the adequate operational conditions, the proposed procedure presented the following useful features: a linear response ranging from 0.1 mg L-1 up to 2.0 mg L-1 sulfate, a detection limit (3σ criterion) of 0.04 mg L-1 sulfate, a relative standard deviation of 1.5% for 0.5 mg L-1 sulfate solution (n = 7), barium chloride consumptions of 17.0 mg per determination, and waste generation of 7.3 mL per determination. Accuracy assessment was achieved by applying the paired t-test between results obtained using the proposed procedure and ICP-OES and showed that there is no significant difference at 95% confidence level.

Investigations on the Rotordynamic Characteristics of a Hole-Pattern Seal Using Transient CFD and Periodic Circular Orbit Model

Numerical investigations on the rotordynamic characteristics of a typical hole-pattern seal using transient three-dimensional Reynolds-averaged Navier–Stokes (RANS) solution and the periodic circular orbit model were conducted in this work. The unsteady solutions combined with mesh deformation method were utilized to solve the three-dimensional RANS equations and obtain the transient reaction forces on a typical hole-pattern seal rotor at five different excitation frequencies. The relation between the periodic reaction forces and frequency dependent rotordynamic coefficients of the hole-pattern seal was obtained by considering the rotor with a periodic circular orbit (including forward orbit and backward orbit) of the seal center. The rotordynamic coefficients of the hole-pattern seal were then solved based on the obtained unsteady reaction forces and presented numerical method. Compared with the experimental data, the predicted rotordynamic coefficients of the hole-pattern seal are more agreeable with the experiment than that of the ISO-temperature (ISOT) bulk flow analysis and numerical approach with one-direction-shaking model. Furthermore, the unsteady leakage flow characteristics in the hole-pattern seal were also illustrated and discussed in detail.

Test beam studies for a highly granular GRPC Semi-Digital HCAL

The Particle Flow Analysis approach retained for the future ILC detectors requires high granularity and compact particle energy deposition. A Glass Resistive Plate Chamber based Semi-Digital calorimeter can offer both at a low price for the hadronic section. This paper presents some recent developments and results near test beam in the use of Glass Resistive Plate Chamber with embedded front-end electronics to build a prototype based on this principle. All the critical parameters such as the spatial and angular uniformity of the response as well as the noise level have been measured on small chambers and found to be appropriate. Small semi-conductive chambers allowing for high rates and a large chamber have also been tested.

Temporal Causal Relationship between Resource Use and Economic Growth in East China

AbstractThe present paper attempts to combine cointegration theory and the material flow analysis approach to examine the causal relationship between resource use and real GDP in Jiangsu Province in East China. The study considers the period from 1990 to 2007. We use direct material input as the proxy variable for resource use. Our estimation indicates that real GDP and resource use are cointegrated and there is only unidirectional long‐run Granger causality running from resource use to real GDP, but not vice versa. The estimation results mean that resources are a limiting factor in terms of economic growth, and, therefore, strategies should be adopted for more vigorous economic development and consistent resource use in East China. Furthermore, the novel idea and methodology involved in the present study can be readily extended to cover other regions for the analysis of the relationship between resource use and economic growth.

Material flow analysis of phosphorus through food consumption in two megacities in northern China

The key stocks and flows of phosphorus (P) through food consumption in Beijing and Tianjin, two megacities in northern China, were explored using a material flow analysis (MFA) approach to construct a static model of P metabolism. A total of 4498 t P has accumulated with 72% of P flow imported through food consumption eventually remaining in Beijing in 2008. Around 64% of the total inflow of P (2670 t) remained in Tianjin in 2008. P in the uncollected sewage from both urban and rural residents and the effluents from sewage treatment plants has significant negative effects on water quality. An average of 55% the P flow remained in the sewage sludge through urban food consumption. The key problems in P metabolism and management in megacities are identified based on the quantitative analysis of P cycling through food consumption. Relevant solutions for improving P recycling efficiency are also discussed. It is important to link P flows with environmental regulations and to establish a strong coordination between urban and rural areas for nutrient recycling to attain sustainable development of megacities.

Hypergraph-oriented 3D reconstruction, interpretation and analysis of air flows

The paper introduces a new air flow analysis approach based on particle tracking velocimetry (PTV). One of the special features of the proposed method is that after the tracer particles are detected, matching and tracking are jointly conducted. To this end, we introduce an interpretation module based on a directed hypergraph for 3D curve reconstruction. At first, the 2D inter-frame locations are localised and used for the extraction and calculation of 3D keypoints. Through 3D keypoints, which are evaluated by the hypergraph together with the time information in several steps, reverse curve matching for path selection can be reconstructed and the resulting trajectories visualised. In contrast to the preceding works, our approach tries to describe the measuring data by 3D trajectories directly instead of estimating 2D trajectories first and then matching afterwards. A higher precision can be achieved also with complicated trajectories. A certain independence of the reflections and lighting conditions is reached by the interpretation. Moreover, the path of particles can also be reconstructed with the minimum number of 3D keypoints under consideration of the path energy minimisation.

Estimating construction and demolition debris generation using a materials flow analysis approach

The magnitude and composition of a region’s construction and demolition (C&D) debris should be understood when developing rules, policies and strategies for managing this segment of the solid waste stream. In the US, several national estimates have been conducted using a weight-per-construction-area approximation; national estimates using alternative procedures such as those used for other segments of the solid waste stream have not been reported for C&D debris. This paper presents an evaluation of a materials flow analysis (MFA) approach for estimating C&D debris generation and composition for a large region (the US). The consumption of construction materials in the US and typical waste factors used for construction materials purchasing were used to estimate the mass of solid waste generated as a result of construction activities. Debris from demolition activities was predicted from various historical construction materials consumption data and estimates of average service lives of the materials. The MFA approach estimated that approximately 610–780 × 10 6 Mg of C&D debris was generated in 2002. This predicted mass exceeds previous estimates using other C&D debris predictive methodologies and reflects the large waste stream that exists.

Diffuse subsurface zinc loads from mining areas in the Dalälven River Basin, Sweden

The zinc load from the Dalälven River to the Baltic Sea is greater than for any other watercourse in Sweden. This paper investigates zinc mass flows into and through the Dalälven River from major mining areas within its drainage basin. Reported zinc mass flow data for this river are re-analyzed using an input-output flow analysis approach. Results show major inconsistencies in previous data interpretations which totally neglected possible zinc mass load contributions from the groundwater system to the river. This paper quantifies significant subsurface zinc load contributions that are consistent with all independently available data. Furthermore, a possible explanation for why these subsurface contributions may have been missed in previous studies and by the prevailing Swedish environmental monitoring system is provided. The study indicates that the input-output flow analysis approach may be generally useful for identifying and quantifying diffuse, unmonitored and uncertain pollutant load contributions from ground- to surface water systems.

The evolution of phosphorus metabolism model in China

It is important to analyze why phosphorus metabolism is unsustainable in China's modern industrial society. In this paper, the Substance Flow Analysis (SFA) approach is used to build different models of phosphorus metabolism for the following three periods: the prehuman period, traditional agricultural period and modern industrial period. Based on these models, the evolution process of phosphorus metabolism in China is analyzed from the viewpoint of its metabolic structure and intensity. The indices of intensity analysis involve phosphorus input, phosphorus circulation and recycling efficiency, phosphorus production and production efficiency, water phosphorus emission and water emission proportion, solid waste phosphorus output and solid waste discharge proportion. Through the analysis of the evolution process, the key factors that cause the lack of sustainability of phosphorus metabolism in China are identified, which can be summarized by four aspects: the increase of soil phosphorus accumulation, the increase of water phosphorus emission, the decrease of recycling efficiency and the decrease of production efficiency in croplands. Furthermore, the specific unsustainable processes of phosphor resources utilization in China are discussed. For these unsustainable processes, the relevant solutions for the phosphor resources crisis are given.

An new approach for the automatic analysis and control of material handling systems: integrated layout flow analysis (ILFA)

In the majority of small and medium sized enterprises (SEMs), the direct costs of material handling cannot be clearly measured. There are several reasons for this, including the large number of product types, complexity of their production cycle, and continuous change in markets. Therefore, production managers require flexible tools to create a suitable material handling system model which explicitly and rapidly calculates the indices required as these are traditionally neglected or laboriously approximated, (i.e., time and cost in material flow inside the factory, storage area requirements, and MH utilization percentage). This paper proposes an integrated approach to analyzing and controlling material handling operations in an industrial manufacturing plant from a “full quantitative” point of view. The model presented unites quite different fields of research into a unique methodology. This material handling model rapidly and automatically provides production managers with extensive and significant information. As a result, integrated layout flow analysis interrelates systematic layout planning with operational research algorithms and visual interactive simulation, using a complete software platform to implement them. This integrated layout flow analysis approach focuses on determining the space requirement for manufacturing department buffers, the transportation system requirements, the performance indices, and the time and cost of material flows spent in the layout and in MH traffic jams.

Extending group technology to the identification and the analysis of enterprises networks

This paper proposes a practical tool for the identification and analysis of industrial networks among a set of enterprises already linked by trade relationships. The methodology extends the group technology (GT) and the production flow analysis (PFA) approach, widely applied in organising the production inside industrial plants. The main advantage of this approach is the small set of data needed to get a feasible solution. An heuristic procedure, sketched at several degrees of analysis, allows not only the identification of the industrial network, but also, with the contribution of other analytical and theoretical studies, the exploitation of potential or existing organisational structure. If properly supported by other studies covering remaining aspects (social, political) of industrial organisation, the tool could be practically useful in recognising possible improvements in the organisation of a given set of enterprises, or also could be used as an investigation instrument for public bodies in exploiting existing or hidden potential industrial networks.

Steady-State Model and Power Flow Analysis of Electronically-Coupled Distributed Resource Units

This paper presents closed-form steady-state, fundamental-frequency models of power electronic converter systems for coupling distributed resource (DR) units to the utility power grid. Based on the developed models, the paper introduces a two-step power flow analysis approach that accurately and efficiently represents electronically-coupled DR units. A feature of the proposed approach is that it solves for the internal variables of each DR unit in a non-iterative fashion based on the presented closed-form DR models, and thus, enhances efficiency and accuracy of the solution. This papers provides the details for steady-state closed-form formulation of matrix converter and voltage-sourced ac-dc-ac converter for coupling DR units. However, the presented methodology is conceptually applicable to other types of converter systems. An application of the proposed power flow approach to a micro-grid that includes two electronically-coupled DR units is also presented

An enzymatic flow analysis methodology for the determination of nitrates and nitrites in waters

An enzymatic flow analysis approach, based on the Griess–Ilosvay reaction, was developed for the evaluation of nitrite and nitrate, aiming at an environmentally benign alternative reduction method using nitrate reductase and the development of an in-line dilution procedure for the analysis of water samples, with a wide range of nitrate concentrations. Nitrate concentrations up to 250 mg/L can be analysed directly in the automatic system, by changing the aspirated sample volume or by applying the in-line dilution procedure provided by the automatic system. Under the optimum conditions, the calibration curves were linear up to 50 mg/L of nitrate and 3 mg/L of nitrite, with the detection limits being 0.73 mg/L and 0.03 mg/L, respectively. Nitrate and nitrite were determined in different water types by the flow method with rsd<5%. Comparison with the reference methods showed no statistically significant differences for a 95% confidence level.

Material Flow and Ecological Restructuring in China

SummaryEnvironmental problems are closely related to society' processing of materials through the entire economy. Because neither traditional environmental nor economic analytical methods can provide sufficient insight into the physical dimension of economies, this article presents an integrated methodology, combining a substance flow analysis (SFA) approach and an ecological restructuring analysis. This approach is applied to phosphorus (P) in China, one of the most rapidly growing industrializing economies, in order to better understand of the economy's material use and its change over time. A static national SFA model is developed with statistical data from 1996. By tracking the national economy's P flows from origins to destinations, the critical P flows with respect to environmental impacts are identified. Based on the regime of national P flows, this article analyzes the degree of ecological restructuring by dynamically describing the structural changes of related critical P flows over the last two decades with a set of ecological restructuring indicators (ERIs). Finally, some potential and desired changes are discussed, with the goal of ecologizing the national P flow regime; that is, reducing the ecological impact of the national P flow regime. The methodology of this article illustrates its applicability and value for presenting an overall insight into the physical dimensions of national economies.

An integrated computer-aided system for generation and evaluation of sustainable process alternatives

This paper presents an integrated system for generation of sustainable process alternatives with respect to new process design as well as retrofit design. The generated process alternatives are evaluated through sustainability metrics, environmental impact factors as well as inherent safety factors. The process alternatives for new process design as well as retrofit design are generated through a systematic method that is simple yet effective and is based on a recently developed path flow analysis approach. According to this approach, a set of indicators are calculated in order to pinpoint unnecessary energy and material waste costs and to identify potential design (retrofit) targets that may improve the process design (in terms of operation and cost) simultaneously with the sustainability metrics, environmental impact factors and the inherent safety factors. Only steady state design data and a database with properties of compounds, including, environmental impact factor related data and safety factor related data are needed. The integrated computer-aided system generates the necessary data if actual plant or experimental data are not available. The application of the integrated system is highlighted through a number of examples including the well-known HDA process.

Evaluation of Phosphorus Flows in the Dianchi Watershed, Southwest of China

Environmental problems are closely related to human societies' processing of materials. Along with a rapid economic growth, lake eutrophication has received broad attention in the last two decades in China. As phosphorus is the dominant nutrient in lake environments, this study attempts to examine how human societies extract, utilize and release phosphorus which subsequently leads to eutrophication. Applying substance flow analysis (SFA) approach for the case of Dianchi Lake in southern China, this study establishes a statistical model by balancing the physical quantities of phosphorus flows in 2000. Resource extraction, phosphate industries, agricultural production, livestock breeding, and human living are given focused attentions in the SFA model. The results showed water environment is largely dependent on the local phosphorus metabolism, and thus, if the related phosphorus flows, particularly referring to recycling and wastes flows, could not be re-organized towards a more ecological direction, Dianchi Lake would be unavoidably and continuously suffering eutrophication. Aiming at ecological restructuring of the phosphorus metabolism with respect to economic efficiency and environmental effectiveness, critical options are discussed and future directions in relation to both societal and policy aspects are presented.

Exploiting monosegmented flow analysis to perform in-line standard additions using a single stock standard solution in spectrophotometric sequential injection procedures

The robustness of sequential injection analysis (SIA) was combined with the monosegmented flow analysis (MSFA) approach, in which there is no dispersion of the reaction zone with carrier, to develop a methodology to perform in-line dilution. This approach allows one to know accurately the dilution of sample and reagent inside the monosegment, without the need for determination of dispersion coefficients. As a consequence, the methodology allowed the mechanization of procedures to perform standard additions and to construct analytical curves using a single stock standard solution, with very simple and conventional computation of the sample concentration. The method was illustrated with experiments using the bromothymol blue (BTB) dye, in which no reactions are involved, as well as with the spectrophotometric methodology for determination of Fe(II) using o-1,10-phenanthroline as chromogenic reagent. The resulting method presented a sampling frequency of 30 analyses per hour and a detection limit of 25 μg l −1.

Business process modelling in small‐ to medium‐sized enterprises

Data flow analysis is used in a novel context for business process modelling. A framework is presented together with its enterprise modelling concepts and the associated modelling tools. The framework was specifically developed for small‐ to medium‐sized industries. The strengths and weaknesses of the general data flow analysis approach are discussed in terms of its suitability for Hong Kong’s small‐ to medium‐sized industries. A case example is also presented to illustrate the methodology.