660 research outputs found
Development Of A High Sensitivity Photometric Procedure For The Determination Of Vanadium In Mineral And Fresh Waters Employing A Downsized Multicommuted Flow Analysis Approach
No full textThis article focuses on the development of an analytical procedure for the photometric determination of vanadium in fresh and mineral waters, implemented employing a downsized multicommuted flow analysis approach. A flow system module using solenoid mini-pumps for fluid propelling and a light emitting diode (LED) based photometer were handled employing a microcontroller (PIC18F). Aiming to improve sensitivity, the flow analysis module and the photometer were designed to allow the coupling of a flow cell with an optical pathlength of 150 mm. The photometric procedure was based on the reaction of V(iv) with eriochrome cyanine R, which formed a compound that presented maximum absorption at 560 nm. Samples of river water and mineral water were processed with the intention to assess the effectiveness of both equipment setup and analytical procedure. The proposed setup presented good overall performance including a linear response (r = 0.997) comprising the concentration range of 0.02 to 1.50 μg mL-1 vanadium; reagent consumption of 11.6 μg eriochrome cyanine R and 8.6 mg ascorbic acid per determination; and a detection limit of 13 μg L-1 vanadium. Other useful features including a relative standard deviation of 0.87% (n = 10), a sampling throughput of 47 determination per hour and a waste generation of 2.4 mL per determination were also achieved.62496679674Mukherjee, B., Patra, B., Mahapatra, S., (2004) Toxicol. Lett., 150, p. 135Al-Tayar, N.G.S., Nagaraja, P., Vasantha, R.A., Shresta, A.K., (2012) Environ. Monit. Assess., 184, p. 181Taylor, M.J.C., Marshall, G.D., Williams, S.J.S., VanStaden, J.F., Saling, C., (1996) Anal. Chim. Acta, 329, p. 275Khuhawar, M.Y., Arain, G.M., (2006) Talanta, 68, p. 535Dadfarnia, S., Shabani, A.M.H., Mirshamsi, A., (2011) Turk. J. Chem., 35, p. 625Domingo, J.L., (1996) Reprod. Toxicol., 10, p. 175Amin, A.S., (2003) Spectrochim. Acta, Part A, 59, p. 1025Kumar, A.P., Reddy, P.R., Vanka, K., (2008) Anal. Lett., 41, p. 1022Kumar, K.S., Kang, S.H., Suvardhan, K., Kiran, K., (2007) Environ. Toxicol. Pharmacol., 24, p. 37Pinto, J.J., Garcia-Vargas, M., Moreno, C., (2013) Talanta, 103, p. 161Nakano, S., Tanaka, E., Mizutani, Y., (2003) Talanta, 61, p. 203Amin, A.S., Saber, A.L., Mohammed, T.Y., (2009) Spectrochim. Acta, Part A, 73, p. 195Bhuiyan, M.S., Shibuya, M., Shioda, N., Moriguchi, S., Kasahara, J., Iwabuchi, Y., Fukunaga, K., (2007) Eur. J. Pharmacol., 571, p. 180Rama, M.J.R., Medina, A.R., Diaz, A.M., (2005) Talanta, 66, p. 1333Deng, P.H., Fei, J.J., Zhang, J., Li, J.N., (2009) Microchim. Acta, 165, p. 211Ayora-Canada, M.J., Molina-Diaz, A., Pascual-Reguera, M.I., (2000) Int. J. Environ. Anal. Chem., 76, p. 319Li, Q.M., Zhao, X.H., Jiang, K., Liu, G.G., (2007) Microchim. Acta, 158, p. 123Narayana, S.L., Reddy, K.J., Reddy, S.A.N., Sarala, Y., Reddy, A.V., (2008) Environ. Monit. Assess., 144, p. 341Teshima, N., Kuno, M., Ueda, M., Ueda, H., Ohno, S., Sakai, T., (2009) Talanta, 79, p. 517Cassella, R.J., Oliveira, E.P., Magalhaes, O.I.B., (2006) Talanta, 69, p. 48Aucelio, R.Q., Doyle, A., Pizzorno, B.S., Tristao, M.L.B., Campos, R.C., (2004) Microchem. J., 78, p. 21Sturini, M., Rivagli, E., Maraschi, F., Speltini, A., Profumo, A., Albini, A., (2013) J. Hazard. Mater., 254, p. 179Aydin, I., Aydin, F., Hamamci, C., (2013) Microchem. J., 108, p. 64Manz, A., Graber, N., Widmer, H.M., (1990) Sens. Actuators, B, 1, p. 244Ruzicka, J., (2000) Analyst, 125, p. 1053Vidigal, S.S.M.P., Toth, I.V., Rangel, A.O.S.S., (2010) J. Agric. Food Chem., 58, p. 2071Vidigal, S.S.M.P., Toth, I.V., Rangel, A.O.S.S., (2008) Talanta, 77, p. 494Seo, J., Lee, L.P., (2004) Sens. Actuators, B, 99, p. 615Fonseca, A., Raimundo, I.M., Jr., Rohwedder, J.J.R., Ferreira, L.O.S., (2007) Anal. Chim. Acta, 603, p. 159Lima, M.B., Barreto, I.S., Andrade, S.L.E., Almeida, L.F., Araújo, M.C.U., (2012) Talanta, 100, p. 308Splawna, B.G., Lytle, F.E., (2002) Anal. Bioanal. Chem., 373, p. 519Anthemidis, A.N., Daftsis, E.I., Kalogiouri, N.P., (2014) Anal. Methods, 6, p. 2745Botev, I., (1979) Fresenius' Z. Anal. Chem., 297, p. 419Borges, S.S., Peixoto, J.S., Feres, M.A., Reis, B.F., (2010) Anal. Chim. Acta, 668, p. 3Lavorante, A.F., Morales-Rubio, A., De La Guardia, M., Reis, B.F., (2007) Anal. Chim. Acta, 600, p. 58Fernandes, R.N., Reis, B.F., Morales-Rubio, A., De La Guardia, M., (2009) J. Braz. Chem. Soc., 20, p. 1242Vieira, G.P., Crispino, C.C., Perdigão, S.R.W., Reis, B.F., (2013) Anal. Methods, 5, p. 489Crispino, C.C., Reis, B.F., (2014) Anal. Methods, 6, p. 302Frizzarin, R.M., Rocha, F.R.P., (2014) Anal. Chim. Acta, 820, p. 69Armenta, S., Garrigues, S., De La Guardia, M., (2008) Trends Anal. Chem., 27, p. 497Melchert, W.R., Reis, B.F., Rocha, F.R.P., (2012) Anal. Chim. Acta, 714, p. 8Rocha, F.R.P., Teixeira, L.S.G., Nobrega, J.A., (2009) Spectrosc. Lett., 42, p. 418Boudra, S., Bosquesendra, J.M., Valencia, M.C., (1995) Talanta, 42, p. 1525Dias, T.R., Brasil, M.A.S., Feres, M.A., Reis, B.F., (2014) Sens. Actuators, B, 198, p. 448Rodenas-Torralba, E., Rocha, F.R.P., Reis, B.F., Morales-Rubio, A., De La Guardia, M., (2006) J. Autom. Methods Manage. Chem., p. 1. , 20384Currie, L.A., (1968) Anal. Chem., 40, p. 586http://www.mma.gov.br/port/conama/res/res05/res35705.pdf, Resolution no. 357/2005. accessed in May 2012http://oehha.ca.gov/water/pals/vanadium.html#sthash.2a0asEnm.dpuf, accessed June 201
Sampling Strategies In Sequential Injection Analysis: Exploiting The Monosegmented-flow Approach
No full textAn evaluation of different sampling techniques employing sequential injection analysis (SIA) is described. The reaction between Fe(II) and 1,10-phenanthroline, which needs a pH adjustment with acetate buffer and a prior reduction with hydroxylamine solution, was employed. As a general rule, sensitivity, compared to that of the usual SIA technique, can be enhanced with binary sampling, sandwich sampling and monosegmented flow, in that order. Under the employed conditions, signals 13, 31 and 58% higher than those provided by conventional SIA can be obtained with the binary, sandwich and monosegmented sampling, respectively. The monosegmented-flow approach was applied in determining iron in natural waters and results do not differ significantly from those obtained by ICP/AES at the 95% confidence level. The precision was 1.1%, expressed as relative standard deviation obtained by the measurement of nine replicates of 1.0mgl-1 Fe(III) reference solution. Copyright (C) 1998 Elsevier Science B.V.3661-3257262Skeggs, L.T., (1957) Am. J. Clin. Pathol., 28, p. 311Ruzicka, J., Hansen, E.H., (1975) Anal. Chim. Acta, 78, p. 145Pasquini, C., Oliveira, W.A., (1985) Anal. Chem., 57, p. 2575Karlberg, B., Thelander, S., (1978) Anal. Chim. Acta, 98, p. 1Bergamin F, H., Reis, B.F., Jacintho, A.O., Zagatto, E.A.G., (1980) Anal. Chim. Acta, 117, p. 81Olsen, O., Pessenda, L.C.R., Ruzicka, J., Hansen, E.H., (1984) Analyst, 108, p. 905Zagatto, E.A.G., Reis, B.F., Bergamin F, H., Krug, F.J., (1979) Anal. Chim. Acta, 109, p. 41Faria, L.C., Pasquini, C., (1987) Anal. Chim. Acta, 193, p. 19Reis, B.F., Jacintho, A.O., Mortatti, J., Krug, F.J., Zagatto, E.A.G., Bergamin F, H., Pessenda, L.C.R., (1981) Anal. Chim. Acta, 123, p. 221Ruzicka, J., Marshall, G.D., (1990) Anal. Chim. Acta, 237, p. 329Reis, B.F., Giné, M.F., Zagatto, E.A.G., Lima, J.L.F.C., Lapa, R.A., (1994) Anal. Chim. Acta, 293, p. 129Cladera, A., Torrias, C., Gómez, E., Estela, J.M., Cerdá, V., (1995) Anal. Chim. Acta, 302, p. 297Raimundo I.M., Jr., Pasquini, C., (1997) Analyst, 122, p. 103
Letter from B.F. Wardlaw to George Sibley, September 14, 1837
No full textPrimary Figures: B.F. Wardlaw corresponds with Major Sibley regarding the administration of the estate of the deceased Miss Fulton.
Date: The correspondence is dated September 14, 1837.
Key Events: Wardlaw protests a request to pay a fifty dollar balance standing on a subscription paper against the Fulton estate, noting that a court judgment on the matter had not yet occurred.
Archival Significance: The author argues that the Church failed to conduct temporal matters according to the Article of Agreement, asserting that this breach releases the estate from further pecuniary liability
The social construction of meaning : Reading Animal Farm in the classroom
No full textThe novel, it has generally been assumed, was from its very beginnings a literary form designed to be read by solitary, silent individuals. One consequence of this assumption is that the class novel, read amid all the noise and sociality of the classroom, tends to be treated as a preparation formore authentic, private reading, or even as poor substitute for it. This essay argues that the history of novel-reading is more complicated and more varied than has been assumed; it goes on to explore, through the story of a single lesson, the possibilities for meaning-making that are the product of particular pedagogic practices as well as of the irreducibly social process of reading the class novel
Reis, Barbara (Death, 1890-06-24)
No full textAddress: St. Francis HospitalAge at death: 74506/Pg 76/1890/F W W/Pa./Dr. B.F. Clark/P. Rebold/St. Joseph OldOriginal record filed in drawer labeled 'REIK-REMY'
Recommended from our members
Folder 10: B.F. Maiz - Some Winter Words - Author, 1989
No full textFlyer for the Fall Letters Series featuring author B. F. Maiz and his new book 'Some Winter Words.' The event is hosted by the Junior Black Academy of Arts and Letters on November 4, 1989 at the Dallas Convention Center Complex
Flow Injection Systems With Inductively-coupled Argon Plasma Atomic Emission Spectrometry. Part 1. Fundamental Considerations
No full textFlow injection systems with inductively-coupled argon plasma atomic emission spectromeiry are proposed. Effects of flow rates, injected volumes and mixing Coil lengths are investigated and conditions for the measurement of the flow injection transient signal are discussed. The peak profile measured with the spectrometer corresponds well with the estimate of the true sample zone distribution near the inlet of the spectrometer made by a zone-sampling process; thus the plasma is not a limiting factor in the proposed systems. For plant analysis, the system provides nearly zero sample dispersion and so the inherent sensitivity of the spectrometric method is preserved. The results obtained for 10 elements in the NBS Orchard Leaves reference material (SRM 1571) are in good agreement with the certified values. For determinations of calcium and magnesium in dolomitic limestones, cadmium is used as internal standard and so the merging zones configuration is employed. The proposed system provides medium sample dispersion and permits about 100 samples to be analysed per hour. Relative standard deviations of 1.34% and 1.23% were calculated for the calcium and magnesium data, respectively. The analytical results compare favorably with those obtained by normal i.c.p. spectrometry with pneumatic sample aspiration, after manual sample dilution. © 1981.1302243255IEEE,IEEE Power Electronics Society (PELS),IK4 IKERLAN Research Alliance,OPALT-RT Technologies,Plexim - Electrical Engineering SoftwareRůžička, Hansen, (1975) Anal. Chim. Acta, 78, p. 145Růžička, Hansen, (1980) Anal. Chim. Acta, 114, p. 19Růžička, Hansen, (1981) Flow Injection Analysis, , Wiley-Interscience, New YorkZagatto, Krug, Bergamin F, Jørgensen, Reis, (1979) Anal. Chim. Acta, 104, p. 279Bergamin F, Zagatto, Reis, Krug, (1978) Anal. Chim. Acta, 101, p. 17Yoza, Aoyagi, Ohashi, Tateda, (1979) Anal. Chim. Acta, 111, p. 163Basson, van Staden, (1980) Fresenius Z. Anal. Chem., 302, p. 370Reis, Jacintho, Mortatti, Krug, Zagatto, Bergamin F, Pessenda, (1981) Anal. Chim. Acta, 123, p. 221Beasecker, Williams, (1978) Jarrell—Ash Plasma Newsl., 1 (3), p. 5Rutledge, McClurg, (1980) Jarrell—Ash Plasma Newsl., 3 (3), p. 4Růžička, Hansen, (1978) Anal. Chim. Acta, 99, p. 37Stewart, Růžička, (1976) Anal. Chim. Acta, 82, p. 137Bergamin F, Medeiros, Reis, Zagatto, (1978) Anal. Chim. Acta, 101, p. 9Bergamin F, Reis, Jacintho, Zagatto, (1980) Anal. Chim. Acta, 117, p. 81Hansen, Růžička, (1976) Anal. Chim. Acta, 87, p. 353Zagatto, Reis, Bergamin F, Krug, (1979) Anal. Chim. Acta, 109, p. 45Giné, Bergamin F, Zagatto, Reis, (1980) Anal. Chim. Acta, 114, p. 191Reis, Zagatto, Jacintho, Krug, Bergamin F, Merging zones in flow injection analysis (1980) Analytica Chimica Acta, 119, p. 305Krug, Bergamin F, Zagatto, Jørgensen, (1977) Analyst, 102, p. 503Pinta, (1975) Atomic Absorption Spectrometry, p. 146. , Adam Hilger, LondonBradbury, (1978) Jarrell—Ash Plasma Newsl., 1 (2), p. 1Jones, Jr., (1978) Jarrell—Ash Plasma Newsl., 1 (1), p.
MANOVA modelling of a chiropractic longitudinal study using multiple imputation
No full textThe purpose of this report is to present the detailed statistical analysis of a randomised, placebo-controlled trial comparing two different treatment modalities to an intervention of no known benefit for people with acute or subacute thoracic spine pain.
The therapy arms consist of Spinal Manipulative Therapy (SMT) and Graston Technique (GT) and the placebo is a non-functional ultrasound. A placebo group was utilised because at present there are no proven treatments for non-specific thoracic pain. This trial is registered with the Australia and New Zealand Clinical Trials Registry. Ethics approval has been granted by Murdoch University Human Research and Ethics Committee, number 2007/274.
The aim of this three arm trial was to test the efficacy of SMT and GT as independent modalities compared to detuned ultrasound for the outcomes of pain and disability. The latter were measured using the Visual Analogue Scale (VAS) and a modified Oswestry Back Pain Disability Index. The study was conducted at the Murdoch University Chiropractic student clinic in Perth, Australia, and the protocol published in Crothers et al (2008).
In this report, Section 2 provides an initial exploratory analysis of the data, Section 3 outlines the statistical models used in the final analysis, Section 4 defines these models in mathematical terms, Section 5 discusses the management of missing values via multiple imputation and Section 6 presents the results of the statistical modelling and hypothesis tests. The clinical study will be published in full elsewhere
A Versatile Set Up For Implementing Different Flow Analysis Approaches: Spectrophotometric Determination Of Nickel In Steel Alloys
No full textAn arrangement capable of implementing the four principal types of flow analysis processes, monosegmented flow analysis (MSFA), flow injection analysis with multicommutation and binary sampling (FIA-MBS), flow injection analysis with sandwich sampling (FIA-SS) and sequential injection analysis (SIA) is described. The core of the flow manifold is a six-way solenoid valve that is assembled together with three three-way solenoid valves in order to provide a versatile flow network. Software was written in VisualBasic 3.0 to give a friendly working structure allowing the user to easily choose the flow variables and the kind of flow system. The reliability of the flow set up for implementation of the four flow analysis systems was evaluated by means of the spectrophotometric determination of nickel in steel alloys, based on the formation of a colored complex with dimethylglyoxime (DMG). The performances of the four different flow methodologies were compared. The reagent consumptions per determination were 4.0 mg of triethanolamine, 6.0 mg of potassium persulfate and 0.6 mg of DMG. When the flow set up was instructed through the software to implement MSFA, FIA-MBS, and FIA-SS approaches, a sampling frequency of 40 samples/h was obtained, while 30 samples could be processed per hour in the SIA mode. The precisions, evaluated as the relative standard deviation of ten determinations were 0.7%, 1.6%, 1.8% and 3.1% for the MFSA, FIA-MBS, FIA-SS and SIA systems, respectively. The results for determination of nickel in steel alloys presented good agreement with the reference method (ICP OES), showing no significant difference at a confidence level of 95%. © 2005 Elsevier B.V. All rights reserved.8215660Skeggs Jr., L.T., An automatic method for calorimetric analysis (1957) Am. J. Clin. Pathol., 28, p. 311Ruzicka, J., Hansen, E.H., Flow injection analyses: 1. New concepto of fast continuous-flow analysis (1975) Anal. Chim. Acta, 78, p. 145Paixão, T.R.L.C., Matos, R.C., Bertotti, M., Diffusion layer titration of dipyrone in pharmaceuticals at a dual-band electrochemical cell (2003) Talanta, 61, p. 725Mana, H., Spohn, U., Sensitive and selective flow injection analysis of hydrogen sulfite/sulfur dioxide by fluorescence detection with and without membrane separation by gas diffusion (2001) Anal. Chem., 73, p. 3187Alonso, A., Almendral, M.J., Porras, M.J., Curto, Y., De Maria, C.G., Flow-injection solvent extraction with and without phase separation - Fluorimetric determination of aluminium in water (2001) Anal. Chim. Acta, 447, p. 211Zhang, Z.F., Chen, S.Y., Yu, H.M., Sun, M., Liu, W.Q., Simultaneous determination of arsenic, selenium, and mercury by ion exchange-vapor generation-inductively coupled plasma-mass spectrometry (2004) Anal. Chim. Acta, 513, p. 417Huang, C.Y., Beauchemin, D., Direct multielemental analysis of human serum by ICP-MS with on-line standard addition using flow injection (2003) J. Anal. Atom. Spectrom., 18, p. 951Pasquini, C., Oliveira, W.A., Monosegmented system for continuous-flow analysis - Spectrophotometric determination of chromium(VI), ammonia, and phosphorus (1985) Anal. Chem., 57, p. 2575Ruzicka, J., Marshall, G.D., Sequential injection - A new concept for chemical sensors, process analysis and laboratory assays (1990) Anal. Chim. Acta, 237, p. 329Reis, B.F., Giné, M.F., Zagatto, E.A.G., Lima, J.L.F.C., Lapa, R.A.S., Multicommutation in flow analysis: 1. Binary sampling - Concepts, instrumentation and spectrophotometric determination of iron in plant digests (1994) Anal. Chim. Acta, 293, p. 129Cerda, V., Estela, J.M., Forteza, R., Cladera, A., Becerra, E., Altimira, P., Sitjar, P., Flow techniques in water analysis (1999) Talanta, 50, p. 695Honorato, R.S., Araújo, M.C.U., Lima, R.A.C., Zagatto, E.A.G., Lapa, R.A.S., Lima, J.L.F.C., A flow-batch titrator exploiting a one-dimensional optimisation algorithm for end point search (1999) Anal. Chim. Acta, 396, p. 91De Almeida, L.F., Da Silva, E.C., Moreira, P.N.T., Araujo, M.C.U., An automatic flow-batch standard-addition method for sodium determination in alcohol fuel by flame photometry (2003) J. Braz. Chem. Soc., 14, p. 249Marczenko, Z., (1986) Separation and Spectrophotometric Determination of Elements, , 2nd ed. Wiley New YorkMartelli, P.B., Reis, B.F., Kronka, E.A.M., Bergamin Fo., H., Korn, M., Zagatto, E.A.G., Lima, J.L.F.C., Araújo, A.N., Multicommutation in flow-analysis. 2. Binary sampling for spectrophotometric determination of nickel, iron, chromium in steel alloys (1995) Anal. Chim. Acta, 308, p. 39
Airline and Alliance Networks: Topology and Robustness from a Complex Network Approach
No full textIncreased market deregulation and the accompanied rise of LCCs over the last decades has put profit for many of the old FSCs under pressure forcing them to merge and form alliances. This sparked the research into finding the most efficient structure for a single airline network in terms of profit and passenger mobility. Along with this, the social and economical dependancy on air transport grew and hence the need to assess the robustness of the network rose. Complex network theory offers a way to assess the efficiency of the networks using amongst other the degree (distribution), the betweenness, the average path length and the clustering coefficient. The main focus of current literature is on the analysis of global and regional airport networks, with limited coverage of separate airline networks and codeshare and alliance formation. Furthermore current research uses very standardized methods of assessing robustness and more realistic assumptions are needed. The first aim of this study is to get an insight into the differences in structure of FSCs and LCCs by analyze the topology and robustness of 17 European separate airline networks, using complex network theory. The second aim is to investigate the influence of codeshare and alliance formation on the topology and robustness of ATNs. Finally the third aim is to improve the methods used to analyze the robustness of ATNs. First the topology of the seperate airline networks of both FSCs and LCCs is analyzed in order to distinguish between the business solutions used by the airlines (PPs and HSs). Additionaly the influence of using codeshares and an alliances on the topology of the airline networks is investigated. This is performed by using complex network indicators to compare the seperate and combined (both codeshare and alliance) network layouts. The analysis confirms literature regarding FSCs, which turn out to use SFN associated with HS. LCCs however, are found not found to have RN associated with PP as suggested in literature, but a SFN with multiple interconnected hubs. The most important difference found between FSCs and LCCs is that LCCs tend to focus on diversity of destinations over frequency, whilst FSCs tend to focus on frequency over diversity. Combining networks into codeshare networks or the Skyteam alliance, increases the diversity of the network, the size and number of hubs and brings the behaviour closer to LCCs, however still with a focus on frequency over diversity. After this the synthetic static robustness of the seperate airline, codeshare and the Skyteam alliance networks is investigated in order to distinguish between the robustness behaviour of both FSCs and LCCs. The link between the complex network indicators and the synthetic static robustness of the ATN is also explored. This is performed by simulating error and attack on the separate airline networks and the codeshare and Skyteam alliance networks. Error is based on the random removal of airports from the network, while attack is based on the consecutive removal of nodes based on the heights of the degree, seat strength and (weighted) betweenness of the airports. The analysis confirms literature regarding FSCs, which shows low robustness against attack and high robustness against error. LCCs again show similar behaviour as the FSCs, contradicting literature, but confirming the results from Chapter 3. The shape of the curve of the cumulative degree distribution can be directly linked to the robustness independant of the size of the network. The higher the amount of hubs (with relative high degree), the higher robustness against attack. The robustness against error is much higher and similar for all networks. Combining networks into codeshare netrworks or the Skyteam alliance, will thus increase the robustness against attack. Finally the robustness analysis of ATNs is improved by introducing new methods of simulating more realistic error and attack scenarios. The link between the realistic robustness analysis and the synthetic robustness analysis is also investigated Three different phenomena are simulated: weather, strikes and volcano eruptions. Weather and volcano eruptions are simulated using the introduced geographic attack. Geographic attack is based on starting at an initiation airport and removing the other airports using geographic radial spreading. Strikes are simulated using the geographic degree, which groups the airport into FIR. The analysis puts the synthetic robustness in perspective. It shows that not only the number of hubs is important in order to improve the robustness of an ATN, but also the geographic spreading of the hubs.Air Transport and OperationsControl and OperationsAerospace Engineerin
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