Bandpass filters for space applications with wide spurious-free range

Design of microwave llters is an important activity, due to the fact that microwave are an integral part of a lot of communications systems; specially in spatial commu- nications systems or terrestrial mobile systems. In the microwave eld, waveguide technology still has a very large acceptance, above all in high power applications, and the cases in which the losses reduction is an important factor that has to be taken into account. In this project, it will be reviewed waveguide technology for bandpass lters design and new techniques which try to increase the spurious-free range will be investi- gated. Concretely, a new concept will be explored in order to remove such spurious band. This technique is based on the control of the coupling windows widht. In addition, it has been worked in the design of a bandpass lter for an antenna phase array that work at S-band. This lter has been designed in SIW (Substrate Inte- grated Waveguide) technology. Finally, it has been studied the use of this waveguide loaded with Ring Resonators and Complementary Split Ring Resonator (CSRR) for the realization of bandpass ters with size reduction.Escuela Técnica Superior de Ingeniería de TelecomunicaciónUniversidad Politécnica de Cartagen

Efficiency of the solution representations for the hybrid flow shop scheduling problem with makespan objective

In this paper we address the classical hybrid flow shop scheduling problem with makespan objective. As this problem is known to be NP-hard and a very common layout in real-life manufacturing scenarios, many studies have been proposed in the literature to solve it. These contributions use different solution representations of the feasible schedules, each one with its own advantages and disadvantages. Some of them do not guarantee that all feasible semiactive schedules are represented in the space of solutions –thus limiting in principle their effectiveness– but, on the other hand, these simpler solution representations possess clear advantages in terms of having consistent neighbourhoods with well-defined neighbourhood moves. Therefore, there is a trade-off between the solution space reduction and the ability to conduct an efficient search in this reduced solution space. This trade-off is determined by two aspects, i.e. the extent of the solution space reduction, and the quality of the schedules left aside by this solution space reduction. In this paper, we analyse the efficiency of the different solution representations employed in the literature for the problem. More specifically, we first establish the size of the space of semiactive schedules achieved by the different solution representations and, secondly, we address the issue of the quality of the schedules that can be achieved by these representations using the optimal solutions given by several MILP models and complete enumeration. The results obtained may contribute to design more efficient algorithms for the hybrid flow shop scheduling problem.Ministerio de Ciencia e Innovación DPI2016-80750-

Using real-time information to reschedule jobs in a flowshop with variable processing times

Versión revisada. Embargo 36 mesesIn a time where detailed, instantaneous and accurate information on shop-floor status is becoming available in many manufacturing companies due to Information Technologies initiatives such as Smart Factory or Industry 4.0, a question arises regarding when and how this data can be used to improve scheduling decisions. While it is acknowledged that a continuous rescheduling based on the updated information may be beneficial as it serves to adapt the schedule to unplanned events, this rather general intuition has not been supported by a thorough experimentation, particularly for multi-stage manufacturing systems where such continuous rescheduling may introduce a high degree of nervousness in the system and deteriorates its performance. In order to study this research problem, in this paper we investigate how real-time information on the completion times of the jobs in a flowshop with variable processing times can be used to reschedule the jobs. In an exhaustive computational experience, we show that rescheduling policies pay off as long as the variability of the processing times is not very high, and only if the initially generated schedule is of good quality. Furthermore, we propose several rescheduling policies to improve the performance of continuous rescheduling while greatly reducing the frequency of rescheduling. One of these policies, based on the concept of critical path of a flowshop, outperforms the rest of policies for a wide range of scenarios.Ministerio de Ciencia e Innovación DPI2016-80750-

Extraction and recovery of phenolic compounds from olive leaves

Póster presentado en: 9º congreso Internacional de Química de la ANQUE. Alimentos y bebidas, 17 a 20 de junio de 2018, MurciaThere is currently a great interest on the use of the residual biomass originated from the agricultural and food sectors as a bioresource instead as a waste, due to its high potential for the recovery of high added-value compounds. Olive leaves, an olive oil processing residue, contain high amounts of phenolic compounds with health-promoting properties, such as oleuropein, tyrosol and hydroxytyrosol. These compounds can be extracted from olive leaves to be added later in processed foods and thus increase their healthy properties. In this work, the recovery of phenolic compounds present in previously ground olive leaves (size less than 1 mm) was carried out by solid-liquid extraction using several solvents (hexane, ethanol, methanol and ethyl acetate). The olive leaves used were kindly provided by the cooperative "Pagos de Benaval" from olive trees of the variety "Serrana de Espadán", endemic of the Sierra de Espadán natural park (Castellón, Spain). The total phenolic content (TPC) in extracts was determined according to the Folin- Ciocalteau method. Olive leaf extract profile and quantitative determination of oleuropein and hydroxytyrosol were performed in an HPLC-DAD system, and also in a LC-MS system. The antioxidant activity of the extracts was determined by the DPPH and ABTS assays. The best results, with a high antioxidant activity and also a high oleuropein and hydroxytyrosol content in the extracts, were obtained when ethanol and methanol were used as solvents. Finally, a central composite design was performed to determine the effect of three factors (extraction temperature (25-40 ºC), solvent volumeleaf mass ratio (5-15 mL/g) and alcohol-to-water ratio (50-90 vol. %)) on TPC, antioxidant activity, and oleuropein and hydroxytyrosol content in the extracts, in order to optimize the extraction process.Junta de Castilla y León and the European Regional Development Fund through project BU055U1

Deterministic Assembly Scheduling Problems: A Review and Classification of Concurrent-Type Scheduling Models and Solution Procedures

Many activities in industry and services require the scheduling of tasks that can be concurrently executed, the most clear example being perhaps the assembly of products carried out in manufacturing. Although numerous scientific contributions have been produced on this area over the last decades, the wide extension of the problems covered and the lack of a unified approach have lead to a situation where the state of the art in the field is unclear, which in turn hinders new research and makes translating the scientific knowledge into practice difficult. In this paper we propose a unified notation for assembly scheduling models that encompass all concurrent-type scheduling problems. Using this notation, the existing contributions are reviewed and classified into a single framework, so a comprehensive, unified picture of the field is obtained. In addition, a number of conclusions regarding the state of the art in the topic are presented, as well as some opportunities for future research.Ministerio de Ciencia e Innovación español DPI2016-80750-

Assessing the potential of decentralised scheduling: An experimental study for the job shop case

-Part of special issue: 10th IFAC Conference on Manufacturing Modelling, Management and Control MIM 2022: Nantes, France, 22-24 June 2022. -Copyright © 2022 The Authors. This is an open access article under the CC BY-NC-ND license.In this paper we investigate how decentralised scheduling approaches can be used to improve manufacturing scheduling. In view of the potential shown by some of these novel decentralised approaches, we conduct a series of experiments on a set of job shop instances subject to different degrees of variability in their processing times, and compare the performance of different scoring methods under the Contract Net Protocol proposed by Guizzi et al. (2019) with the objective of minimizing the expected makespan. We also compare the performance of the optimal (centralised and deterministic) solution in the stochastic setting, as well as a hybrid centralised-decentralised approach. Despite some limitations in the experiments, the results show the excellent performance of the decentralised approach if its operating parameters are optimized, and that the hybrid approach serves to overcome some of the problems of both centralised and decentralised approaches

Design of 300 ghz combined doubler/subharmonic mixer based on schottky diodes with integrated mmic based local oscillator

In this paper the design and experimental characterization of a combined doublersubharmonic mixer based on Schottky diodes which uses a 75 GHz MMIC based local oscillator is presented. This solution integrates in the same substrate the doubler and the mixer, which share the same metallic packaging with the local oscillator. The prototype has been fabricated and measured. For characterization, the Y-Factor technique has been used and the prototype yields a best conversion loss and equivalent noise temperature of 11 dB and 1976 K, respectively, at 305 GHz. This performance is close to the state of the art, and shows the potential of this approach, which allows a significant reduction in terms of size and volume.This research was funded by the Spanish MINECO, Project No. TEC2016-76997-C3-1-R, and by the Spanish State Research Agency, Project No. PID2019-109984RB-C43/AEI/10.13039/501100011033