117 research outputs found

    Mount assembly for porous transition panel at annular combustor outlet

    Get PDF
    A gas turbine engine combustor assembly of annular configuration has outer and inner walls made up of a plurality of axially extending multi-layered porous metal panels joined together at butt joints therebetween and each outer and inner wall including a transition panel of porous metal defining a combustor assembly outlet supported by a combustor mount assembly including a stiffener ring having a side undercut thereon fit over a transition panel end face; and wherein an annular weld joins the ring to the end face to transmit exhaust heat from the end face to the stiffener ring for dissipation from the combustor; a combustor pilot member is located in axially spaced, surrounding relationship to the end face and connector means support the stiffener ring in free floating relationship with the pilot member to compensate for both radial and axial thermal expansion of the transition panel; and said connector means includes a radial gap for maintaining a controlled flow of coolant from outside of the transition panel into cooling relationship with the stiffener ring and said weld to further cool the end face against excessive heat build-up therein during flow of hot gas exhaust through said outlet

    Architecture framework of IoT-based food and farm systems: A multiple case study

    Get PDF
    The Internet of Things (IoT) is expected to be a real game changer in food and farming. However, an important challenge for large-scale uptake of IoT is to deal with the huge heterogeneity of this domain. This paper develops and applies an architecture framework for modelling IoT-based systems in the agriculture and food domain. The framework comprises a coherent set of architectural viewpoints and a guideline to use these viewpoints to model architectures of individual IoT-based systems. The framework is validated in a multiple case study of the European IoF2020 project, including different agricultural sub sectors, conventional and organic farming, early adopters and early majority farmers, and different supply chain roles. The framework provides a valuable help to model, in a timely, punctual and coherent way, the architecture of IoT-based systems of this diverse set of use cases. Moreover, it serves as a common language for aligning system architectures and enabling reuse of architectural knowledge among multiple autonomous IoT-based systems in agriculture and food

    Systemic, pulmonary and coronary haemodynamic actions of the novel dopamine receptor agonist in awake pigs at rest and during treadmill exercise Z1046

    Get PDF
    1. In view of the potential therapeutic application of specific dopamine receptor agonists in the treatment of hypertension and left ventricular dysfunction, we investigated the cardiovascular actions of the novel mixed D1/D2 dopamine receptor agonist Z1046 in awake pigs at rest and during treadmill exercise. 2. Thirteen swine were chronically instrumented under sterile conditions for measurement of systemic, pulmonary, and coronary haemodynamics. Regional blood flows were determined with the radioactive microsphere technique. 3. Z1046 (1, 10, 100 μg kg-1, i.v.) produced dose-dependent reductions in central aortic blood pressure (up to 27 ± 3%, P ≤ 0.05) in awake resting pigs which was accompanied by only minimal reflex activation of the sympathetic nervous system. The hypotensive response was principally the result of peripheral vasodilatation (system vascular resistance decreased up to 35 ± 4%, P ≤ 0.05), which was located in the cerebral, coronary, renal, mesenteric, adrenal, splenic and skeletal muscular vascular beds (vascular resistance decreased up to 30-40% after the highest dose in these beds). Only in the cerebral and mesenteric bed was the vasodilatation sufficiently large to overcome the decrease in blood pressure and result in an increased blood flow; the vasodilatation in the coronary bed was most likely due to autoregulation as neither coronary blood flow nor myocardial oxygen demand were changed significantly by Z1046. The systemic vasodilatation that was caused by the highest i.v. dose (100 μg kg-1) was accompanied by transient and minor increases in heart rate (15 ± 5%, P ≤ 0.05) and cardiac output (15 ± 5%, P ≤ 0.05) whereas after 10 μg kg-1, i.v., a slight decrease in cardiac output also contributed to the hypotension. Z1046 had no effect on pulmonary vascular resistance. 4. The systemic vasodilator responses to Z1046 (100 μg kg-1, i.v.) were sustained during treadmill exercise (2-4 km h-1 which produced heart rates of up to 233 ± 10 beats min-1), but with increasing treadmill speed attenuation of the exercise-induced increase in heart rate (-11 ± 3%, P ≤ 0.05) and hence cardiac output (-10 ± 3%, P ≤ 0.05) (as stroke volume was not altered by Z1046) contributed significantly to a lower aortic blood pressure (-20 ± 3%, P ≤ 0.05). Z1046 had no effect on pulmonary vascular resistance during exercise. 5. Oral administration of Z1046 (0.5, 1.5 mg kg-1) produced a fall in central aortic blood pressure (up to 15 ± 3%, P ≤ 0.05), which developed gradually during the first 90 min and lasted up to 4 h after administration, again with negligible changes in heart rate and LVdP/dt(max). 6. Neither non-selective α- and β-adrenoceptor blockade, nor selective α2-adrenoceptor blockade altered the vasodilator actions of Z1046, but non-selective α- and β-adrenoceptor blockade abolished the cardiac responses to dopamine receptor stimulation, suggesting that its cardiac actions were principally caused by D2-receptor-mediated inhibition of catecholamine release, whereas the vasodilator response was probably the result of vascular D1-receptor stimulation. 7. In conclusion, the novel dopamine receptor agonist Z1046 is an effective blood pressure lowering agent that elicits minimal reflex activation of the sympathetic nervous system in awake resting pigs. Systemic vasodilatation was not affected by combined α- and β-adrenoceptor blockade, which is consistent with a predominantly D1 receptor-dependent vasodilator mechanism. The hypotensive effect is maintained during treadmill exercise during which systemic vasodilatation and a lower cardiac output both contribute to the blood pressure lowering actions of Z1046. The cardiovascular profile of this orally active compound warrants further investigation of this class of drugs in experimental and clinical hypertension.</p

    Systemic, pulmonary and coronary haemodynamic actions of the novel dopamine receptor agonist in awake pigs at rest and during treadmill exercise Z1046

    Get PDF
    1. In view of the potential therapeutic application of specific dopamine receptor agonists in the treatment of hypertension and left ventricular dysfunction, we investigated the cardiovascular actions of the novel mixed D1/D2 dopamine receptor agonist Z1046 in awake pigs at rest and during treadmill exercise. 2. Thirteen swine were chronically instrumented under sterile conditions for measurement of systemic, pulmonary, and coronary haemodynamics. Regional blood flows were determined with the radioactive microsphere technique. 3. Z1046 (1, 10, 100 μg kg-1, i.v.) produced dose-dependent reductions in central aortic blood pressure (up to 27 ± 3%, P ≤ 0.05) in awake resting pigs which was accompanied by only minimal reflex activation of the sympathetic nervous system. The hypotensive response was principally the result of peripheral vasodilatation (system vascular resistance decreased up to 35 ± 4%, P ≤ 0.05), which was located in the cerebral, coronary, renal, mesenteric, adrenal, splenic and skeletal muscular vascular beds (vascular resistance decreased up to 30-40% after the highest dose in these beds). Only in the cerebral and mesenteric bed was the vasodilatation sufficiently large to overcome the decrease in blood pressure and result in an increased blood flow; the vasodilatation in the coronary bed was most likely due to autoregulation as neither coronary blood flow nor myocardial oxygen demand were changed significantly by Z1046. The systemic vasodilatation that was caused by the highest i.v. dose (100 μg kg-1) was accompanied by transient and minor increases in heart rate (15 ± 5%, P ≤ 0.05) and cardiac output (15 ± 5%, P ≤ 0.05) whereas after 10 μg kg-1, i.v., a slight decrease in cardiac output also contributed to the hypotension. Z1046 had no effect on pulmonary vascular resistance. 4. The systemic vasodilator responses to Z1046 (100 μg kg-1, i.v.) were sustained during treadmill exercise (2-4 km h-1 which produced heart rates of up to 233 ± 10 beats min-1), but with increasing treadmill speed attenuation of the exercise-induced increase in heart rate (-11 ± 3%, P ≤ 0.05) and hence cardiac output (-10 ± 3%, P ≤ 0.05) (as stroke volume was not altered by Z1046) contributed significantly to a lower aortic blood pressure (-20 ± 3%, P ≤ 0.05). Z1046 had no effect on pulmonary vascular resistance during exercise. 5. Oral administration of Z1046 (0.5, 1.5 mg kg-1) produced a fall in central aortic blood pressure (up to 15 ± 3%, P ≤ 0.05), which developed gradually during the first 90 min and lasted up to 4 h after administration, again with negligible changes in heart rate and LVdP/dt(max). 6. Neither non-selective α- and β-adrenoceptor blockade, nor selective α2-adrenoceptor blockade altered the vasodilator actions of Z1046, but non-selective α- and β-adrenoceptor blockade abolished the cardiac responses to dopamine receptor stimulation, suggesting that its cardiac actions were principally caused by D2-receptor-mediated inhibition of catecholamine release, whereas the vasodilator response was probably the result of vascular D1-receptor stimulation. 7. In conclusion, the novel dopamine receptor agonist Z1046 is an effective blood pressure lowering agent that elicits minimal reflex activation of the sympathetic nervous system in awake resting pigs. Systemic vasodilatation was not affected by combined α- and β-adrenoceptor blockade, which is consistent with a predominantly D1 receptor-dependent vasodilator mechanism. The hypotensive effect is maintained during treadmill exercise during which systemic vasodilatation and a lower cardiac output both contribute to the blood pressure lowering actions of Z1046. The cardiovascular profile of this orally active compound warrants further investigation of this class of drugs in experimental and clinical hypertension.</p

    A conceptual framework for crop-based agri-food supply chain characterization under uncertainty

    Get PDF
    [EN] Crop-based Agri-food Supply Chains (AFSCs) are complex systems that face multiple sources of uncertainty that can cause a significant imbalance between supply and demand in terms of product varieties, quantities, qualities, customer requirements, times and prices, all of which greatly complicate their management. Poor management of these sources of uncertainty in these AFSCs can have negative impact on quality, safety, and sustainability by reducing the logistic efficiency and increasing the waste. Therefore, it becomes crucial to develop models in order to deal with the key sources of uncertainty. For this purpose, it is necessary to precisely understand and define the problem under study. Even, the characterisation process of this domains is also a difficult and time-consuming task, especially when the right directions and standards are not in place. In this chapter, a Conceptual Framework is proposed that systematically collects those aspects that are relevant for an adequate crop-based AFSC management under uncertainty.Authors of this publication acknowledge the contribution of the Project 691249, RUC-APS "Enhancing and implementing Knowledge based ICT solutions within high Risk and Uncertain Conditions for Agriculture Production Systems" (www.ruc-aps.eu), funded by the European Union under their funding scheme H2020-MSCA-RISE-2015Alemany Díaz, MDM.; Esteso, A.; Ortiz Bas, Á.; Hernández Hormazabal, JE.; Fernández, A.; Garrido, A.; Martin, J.... (2021). A conceptual framework for crop-based agri-food supply chain characterization under uncertainty. Studies in Systems, Decision and Control. 280:19-33. https://doi.org/10.1007/978-3-030-51047-3_2S1933280Taylor, D.H., Fearne, A.: Towards a framework for improvement in the management of demand in agri-food supply chains. Supply Chain Manage. 11, 379–384 (2006)Matopoulos, A., Vlachopoulou, M., Manthou, V., Manos, B.: A conceptual framework for supply chain collaboration: empirical evidence from the agri-food industry. Supply Chain Manage. 12, 177–186 (2007)Ahumada, O., Villalobos, J.R.: Application of planning models in the agri-food supply chain: a review. Eur. J. Oper. Res. 196, 1–20 (2009)Iakovou, E., Vlachos, D., Achillas, C., Anastasiadis, F.: A methodological framework for the design of green supply chains for the agrifood sector. Paper presented at the 2nd international conference on supply chains, Katerini, 5–7 Oct 2012Manzini, R., Accorsi, R.: The new conceptual framework for food supply chain assessment. J. Food Eng. 115, 251–263 (2013)Shukla, M., Jharkharia, S.: Agri-fresh produce supply chain management: a state-of-the-art literature review. Int. J. Oper. Prod. Manage. 33, 114–158 (2013)Lemma, Y., Kitaw, D., Gatew, G.: Loss in perishable food supply chain: an optimization approach literature review. Int. J. Sci. Eng. Res. 5, 302–311 (2014)Tsolakis, N.K., Keramydas, C.A., Toka, A.K., Aidonis, D.A., Iakovou, E.T.: Agrifood supply chain management: a comprehensive hierarchical decision-making framework and a critical taxonomy. Biosyst. Eng. 120, 47–64 (2014)Van der Vorst, J.G., Da Silva, C.A., Trienekens, J.H.: Agro-industrial Supply Chain Management: Concepts and Applications. FAO (2007)Hernandez, J., Mortimer, M., Patelli, E., Liu, S., Drummond, C., Kehr, E., Calabrese, N., Iannacone, R., Kacprzyk, J., Alemany, M.M.E., Gardner, D.: RUC-APS: enhancing and implementing knowledge based ICT solutions within high risk and uncertain conditions for agriculture production systems. In: 11th International Conference on Industrial Engineering and Industrial Management, Valencia, Spain (2017)Miles, M.B., Huberman, A.M.: Qualitative Data Analysis: An Expanded Sourcebook. Sage Publications, Thousand Oaks (1994)Alemany, M.M.E., Alarcón, F., Lario, F.C., Boj, J.J.: An application to support the temporal and spatial distributed decision-making process in supply chain collaborative planning. Comput. Ind. 62, 519–540 (2011)Teimoury, E., Nedaei, H., Ansari, S., Sabbaghi, M.: A multi-objective analysis for import quota policy making in a perishable fruit and vegetable supply chain: a system dynamics approach. Comput. Electron. Agric. 93, 37–45 (2013)Kusumastuti, R.D., van Donk, D.P., Teunter, R.: Crop-related harvesting and processing planning: a review. Int. J. Prod. Econ. 174, 76–92 (2016)Zhang, W., Wilhelm, W.E.: OR/MS decision support models for the specialty crops industry: a literature review. Ann. Oper. Res. 190, 131–148 (2011)Grillo, H., Alemany, M.M.E., Ortiz, A.: A review of mathematical models for supporting the order promising process under lack of homogeneity in product and other sources of uncertainty. Comput. Ind. Eng. 91, 239–261 (2016)Blanco, A.M., Masini, G., Petracci, N., Bandoni, J.A.: Operations management of a packaging plant in the fruit industry. J. Food Eng. 70, 299–307 (2005)Grillo, H., Alemany, M.M.E., Ortiz, A., Fuertes-Miquel, V.S.: Mathematical modelling of the order-promising process for fruit supply chains considering the perishability and subtypes of products. Appl. Math. Model. 49, 255–278 (2017)Verdouw, C.N., Beulens, A.J.M., Trienekens, J.H., Wolferta, J.: Process modelling in demand-driven supply chains: a reference model for the fruit industry. Comput. Electron. Agric. 73, 174–187 (2010)Amorim, P., Günther, H., Almada-Lobo, B.: Multi-objective integrated production and distribution planning of perishable products. Int. J. Prod. Econ. 138, 89–101 (2012)Nahmias, S.: Perishable inventory theory: a review. Oper. Res. 30, 680–708 (1982)Mowat, A., Collins, R.: Consumer behavior and fruit quality: supply chain management in an emerging industry. Supply Chain Manage. 5, 45–54 (2000)Kazaz, B., Webster, S.: The impact of yield-dependent trading costs on pricing and production planning under supply uncertainty. M&SOM Manuf. Serv. Oper. Manage. 13, 404–417 (2011)Van der Vorst, J.G.: Effective food supply chains: generating, modelling and evaluating supply chain scenarios (2000)Fuertes-Miquel, V.S., Cuenca, L., Boza, A., Guyon, C., Alemany, M.M.E.: Conceptual framework for the characterization of vegetable breton supply chain sustainability in an uncertain context. In: 12th International Conference on Industrial Engineering and Industrial Management, XXII Congreso de Ingeniería de Organización, Girona, Spain, 12–13 July 2018Kummu, M., de Moel, H., Porkka, M., Siebert, S., Varis, O., Ward, P.J.: Lost food, wasted resources: global food supply chain losses and their impacts on freshwater, cropland, and fertiliser use. Sci. Total Environ. 438, 477–489 (2012)Hoekstra, S., Romme, J.: Integral Logistic Structures: Developing Customer-Oriented Goods Flow. Industrial Press Inc., New York (1992)Borodin, V., Bourtembourg, J., Hnaien, F., Labadie, N.: Handling uncertainty in agricultural supply chain management: a state of the art. Eur. J. Oper. Res. 254, 348–359 (2016)Handayati, Y., Simatupang, T.M., Perdana, T.: Agri-food supply chain coordination: the state-of-the-art and recent developments. Logist. Res. 8, 1–15 (2015)Mintzberg, H.: The Structuring of Organisations. Prentice-Hall, Upper Saddle River (1979)Keuning, D.: Grondslagen Van Het Management. Stenfert Kroese, Houten (1995) (in Dutch)Esteso, A., Alemany, M.M.E., Ortiz, A.: Conceptual framework for designing agri-food supply chains under uncertainty by mathematical programming models. Int. J. Prod. Res. (2018)Backus, G.B.C., Eidman, V.R., Dijkhuizen, A.A.: Farm decision making under risk and uncertainty. Neth. J. Agr. Sci. 45, 307–328 (1997)Esteso, A., Alemany, M.M.E., Ortiz, A.: Conceptual framework for managing uncertainty in a collaborative agri-food supply chain context. In: IFIP Advances in Information and Communication Technology, vol. 506, pp. 715–724 (2017)Mundi, I., Alemany, M.M.E., Poler, R., Fuertes-Miquel, V.S.: Review of mathematical models for production planning under uncertainty due to lack of homogeneity: proposal of a conceptual model. Int. J. Prod. Res. (2019)Grillo, H., Alemany, M.M.E., Ortiz, A., De Baets, B.: Possibilistic compositions and state functions: application to the order promising process for perishables. Int. J. Prod. Res. (2019)Soto-Silva, W.E., Nadal-Roig, E., González-Araya, M.C., Pla-Aragones, L.M.: Operational research models applied to the fresh fruit supply chain. Eur. J. Oper. Res. 251, 345–355 (2016)Farahani, R.Z., Rezapour, S., Drezner, T., Fallah, S.: Competitive supply chain network design: an overview of classifications, models, solution techniques and applications. Omega 45, 92–118 (2014)Banasik, A., Bloemhof-Ruwaard, J.M., Kanellopoulos, A., Claassen, G.D.H., van der Vorst, J.G.: Multi-criteria decision making approaches for green supply chains: a review. Flex. Serv. Manuf. J. 1–31 (2016)Paam, P., Berretta, R., Heydar, M., Middleton, R.H., García-Flores, R., Juliano, P.: Planning models to optimize the agri-fresh food supply chain for loss minimization: a review. In: Reference Module in Food Science (2016)Soysal, M., Bloemhof-Ruwaard, J.M., Meuwissen, M.P., van der Vorst, J.G.: A review on quantitative models for sustainable food logistics management. Int. J. Food Syst. Dyn. 3, 136–155 (2012

    Acquisition of Ca2+ and HCO3−/CO32− for shell formation in embryos of the common pond snail Lymnaea stagnalis

    Get PDF
    Embryos of the freshwater common pond snail Lymnaea stagnalis develop to hatch within 10 days under control conditions (22°C, Miami-Dade tap water) and this development is impaired by removal of ambient calcium. In contrast, embryos did not exhibit dependence upon an ambient HCO3−/CO32− source, developing and hatching in HCO3−/CO32−-free water at rates comparable to controls. Post-metamorphic, shell-laying embryos exhibited a significant saturation-type calcium uptake as a function of increasing ambient calcium concentration. However, changes in ambient bicarbonate concentration did not influence calcium or apparent titratable alkalinity uptake. There was a distinct shift from no significant flux in pre-metamorphic embryos to net uptake of calcium in post-metamorphic stages as indicated by an increased uptake from the micro-environment surrounding the egg mass and increased net uptake in 24-h, whole egg mass flux measurements. Furthermore, HCO3−/CO32− acquisition as measured by titratable alkalinity flux is at least partially attributable to an endogenous carbonate source that is associated with acid extrusion. Thus, calcium requirements for embryonic shell formation are met via uptake but HCO3−/CO32−, which is also necessary for shell formation is acquired in part from endogenous sources with no detectable correlation to ambient HCO3−/CO32− availability
    corecore