Optimal experimental design for estimating the kinetic parameters of processes described by the first-order Arrhenius model under linearly increasing temperature profiles

The optimum experimental design for systems following the ®rst-order Arrhenius model under linearly increasing temperature pro®les was studied by determining the sampling conditions that lead to a minimum con®dence region of the model parameters. It was found that experiments should be started at the lowest possible temperature and, for each initial temperature, there is an optimal heating rate. This heating rate is often too high to be feasible, implying that experiments have to be conducted at a lower practicable heating rate. In this situation the experiments should be replicated in order to improve the precision of the estimates. If both the initial temperature and the heating rate are ®xed at their optimal values, the optimal sampling times correspond to fractional concentrations that are irrational numbers (approximately 0.70 and 0.19) whose product is exactly 1=e2, as earlier found for the Bigelow model. A case study based on the estimation of the kinetic parameters of the acid hydrolysis of sucrose is also presente

Immunization strategies for funding multiple inflation-linked retirement income benefits

Simões, C., Oliveira, L., & Bravo, J. M. (2021). Immunization strategies for funding multiple inflation-linked retirement income benefits. Risks, 9(4), [60]. https://doi.org/10.3390/risks9040060Protecting against unexpected yield curve, inflation, and longevity shifts are some of the most critical issues institutional and private investors must solve when managing post-retirement income benefits. This paper empirically investigates the performance of alternative immunization strategies for funding targeted multiple liabilities that are fixed in timing but random in size (inflation-linked), i.e., that change stochastically according to consumer price or wage level indexes. The immunization procedure is based on a targeted minimax strategy considering the M-Absolute as the interest rate risk measure. We investigate to what extent the inflation-hedging properties of ILBs in asset liability management strategies targeted to immunize multiple liabilities of random size are superior to that of nominal bonds. We use two alternative datasets comprising daily closing prices for U.S. Treasuries and U.S. inflation-linked bonds from 2000 to 2018. The immunization performance is tested over 3-year and 5-year investment horizons, uses real and not simulated bond data and takes into consideration the impact of transaction costs in the performance of immunization strategies and in the selection of optimal investment strategies. The results show that the multiple liability immunization strategy using inflation-linked bonds outperforms the equivalent strategy using nominal bonds and is robust even in a nearly zero interest rate scenario. These results have important implications in the design and structuring of ALM liability-driven investment strategies, particularly for retirement income providers such as pension schemes or life insurance companies.publishersversionpublishe

Optimal experimental design for estimating the kinetic parameters of processes described by the Weibull probability distribution function

The optimum experimental design for determining the kinetic parameters of the model resulting from the Weibull probability density junction was studied, by defining the sampling conditions that lead to a minimum confidence region of the estimates, for a number of observations equal to the number of parameters. It was found that for one single isothermal experiment the optimum sampling times corresponded always to fractional concentrations that are irrational numbers (approximately 0.70 and 0.19) whose product is exactly l/e’. The experimental determination of the equilibtium conversion (for growth kinetics) is vety important, but in some situations this is not possible, e.g. due to product degradation over the length of time required. Sampling times leading to a maximum precision were determined as a function of the maximum conversion (or yield) attainable. For studies of kinetic parameters over a range of temperatures, performed with a minimum of three isothermal experiments, it was proved that the optimum design consists of two experiments at one limit temperature with two sampling times (those corresponding to fractional concentrations of approximate[v 0.70 and 0.19) and another at the other limit temperature for a sampling time such that the fractional concentration is lie. Case studies are included for clarijication of the concepts and procedures

Modeling and simulating a textile production system

This paper presents a study for a production scheduling problem in a textile company, specifically in the weaving preparation area. Basically, the processing orders can be considered as sequential working steps trough three operations (charging - weaving - discharging), and the goal is to minimize time variation and to avoid delays. The machine utilization should be as higher as possible due to short delivering deadlines. The production unit has got 4 of these weaving machines functioning at the same time. Four dispatching rules were tested in order to find the best solution. The optimization procedure highlighted some interesting issues that are discussed in this paper

Analyzing the root of regional innovation performance in the European territory

Regional innovation performance is an important indicator for decision-making regarding the implementation of policies intended for regional development. However, regional development policies have led economies to very different competitive positions in matters of innovation. To address these issues, this paper aims to identify the variables that most contribute to the positioning of economies in terms of performance innovation in Europe. The data for this study were collected at the Regional Innovation Scoreboard (RIS). We use a quantitative methodology, through a multivariate statistical technique (Discriminant Analysis). The results suggest that specific innovation strategies explain the competitive positioning of economies within each group of countries. It was possible to demonstrate that economies with Leader classification show greater comparative robustness in the variables “SMEs with Product or Process Innovations”, “SMEs with Product or Process Innovations”, “R&D Expenditure Public Sector” and “Population with Tertiary Education”, constituting an effective instrument of innovation policy. Furthermore, it was possible to show that the economies belonging to the Modest group do not have a competitive advantage in any of the variables under study, thus providing a reflection opportunity for policymakers at this level. The present research identifies which variables are most relevant to the classification considering the regional innovation performance in Leader, Strong, Moderate, and Modest. Several suggestions were given to companies, policy makers, and higher education institutions in the sense that the regions where they operate can improve their innovative performance, which may help to a change in their current classification.info:eu-repo/semantics/publishedVersio

Application of D-optimal design for determination of the influence of water content on the thermal degradation kinetics of ascorbic acid at low water contents

The kinetics of thermal degradation of ascorbic acid was studied in a Maltodextrin matrix at different temperatures between 7.5 and 140°C. Isothermal experiments were performed with samples earlier equilibrated in environments of known a, at 4°C enclosed in hermetically sealed vials, with water contents (w) between 0.17 and 168g water/g solids. Sampling times were selected according to an optimal experimental design in terms of minimum confidence regions of the parameters estimated, using the Bigelow model and estimates from preliminary experiments. The results showed a quadratic dependence of the reference D-value and linear dependence of the z-value with moisture content: D r(1400C, = 150*07-290*73w+-269w2 (min); z = 12*14+22.99w (“C) and showed the applicability of D-optimal designs for determining kinetic parameters in complex situations, with limited experimental requirements. The dependence of the rate constants with water content could not be described by the WLF model in qualitative terms, although in absolute values this model could be used with constants similar to those expected from glass transition theory. The thermodynamic analysis of the results showed a good application of the compensation theory in the whole range of water contents

Waste mud characterization : a contribuition to quarries environmental impact mitigation and to a sustainable use of a natural resource

Poster apresentado no 32nd International Geological Congress, Florença, Itália, 20-28 Ag. 2004.In the northeast Portugal region (Trás-os-Montes), fluvial Cenozoic deposits are an important source of raw materials used in the construction industry. These deposits are mainly composed by gravel and sandy to muddy-gravel bodies, with some muddy-sand and clay bodies. These deposits are preserved in hilltops due to topographic inversion. The deposits are quarried for the extraction of sand and gravel. This coarse fraction is separated from the silt-clay matrix (mud) by wet sieving. The mud matrix consists on about 20-60% of the extracted material. After the wet sieving process, the mud is located in settling tanks, usually placed in abandon areas of the quarries, or in a neighbor area. Because almost all the quarries are placed on hilltops, these tanks are usually found there or in the slopes of the hills. There are some environmental impacts associated to this extractive industry. Landscape degradation due to the decreasing of the topographic level, associated with the visual impact of the quarries and mud tanks. The instability of some mud tanks is another hazard, due to the potential occurrence of mass movements. The mud also reduces the soil development and the vegetation growth. Therefore, soil recovery is a difficult process constituting a negative effect on land populations. To know the main characteristics of these waste muds, compositional studies and technological tests were performed. The results indicate suitability for application in ceramic construction industry (manufacture of bricks, tiles and other related materials). The compositional and technological characterization of these waste muds indicate their potential as a useful sub-product. The use of the waste muds in the ceramic construction industry will increment the economic value of these deposits as a natural resource. This procedure will also contribute to the mitigation of the environmental impact caused by this extractive industry. This approach can be implemented in other quarries contributing to the sustainable use of this natural resource.Fundação para a Ciência e a Tecnologia (FCT) - POCTI/CTA/38659/2001. FEDER

Implementing RRI in a Research and Innovation Ecosystem

Funding Information: We acknowledge the support from the European Commission through the ETHNA System project (Grant Nº 872360). Partial financial support was also provided by Portuguese FCT program UIDB/00066/2020 (CTS – Center of Technology and Systems). Publisher Copyright: © 2023, The Author(s).New organizational forms are emerging today at all levels of society, and more and more research is conducted in dynamic collaborative networks or ecosystems. Unlike traditional research centers, these new types of organization are very dynamic, with fluid boundaries, and volatile in terms of membership. This characteristic requires that more attention be paid to research ethics and RRI. This work reports on an implementation process carried out in a research and innovation ecosystem according to the principles and guidelines proposed by the ETHNA project. The process, its barriers and drivers are described, and finally, learned lessons and recommendations are presented.publishersversionpublishe

On the simulation of the filling stage of thermoplastic injection molding using the open-source solver openInjMoldSim

NORTE-07-0162-FEDER-000086 and the Minho Advanced Computing Center (MACC) for providing HP