Integration of modular process simulators under the Generalized Disjunctive Programming framework for the structural flowsheet optimization

The optimization of chemical processes where the flowsheet topology is not kept fixed is a challenging discrete-continuous optimization problem. Usually, this task has been performed through equation based models. This approach presents several problems, as tedious and complicated component properties estimation or the handling of huge problems (with thousands of equations and variables). We propose a GDP approach as an alternative to the MINLP models coupled with a flowsheet program. The novelty of this approach relies on using a commercial modular process simulator where the superstructure is drawn directly on the graphical use interface of the simulator. This methodology takes advantage of modular process simulators (specially tailored numerical methods, reliability, and robustness) and the flexibility of the GDP formulation for the modeling and solution. The optimization tool proposed is successfully applied to the synthesis of a methanol plant where different alternatives are available for the streams, equipment and process conditions.

The influence of the sample introduction system on signals of different tin compounds in inductively coupled plasma-based techniques

The influence of the sample introduction system on the signals obtained with different tin compounds in inductively coupled plasma (ICP) based techniques, i.e., ICP atomic emission spectrometry (ICP–AES) and ICP mass spectrometry (ICP–MS) has been studied. Signals for test solutions prepared from four different tin compounds (i.e., tin tetrachloride, monobutyltin, dibutyltin and di-tert-butyltin) in different solvents (methanol 0.8% (w/w), i-propanol 0.8% (w/w) and various acid matrices) have been measured by ICP–AES and ICP–MS. The results demonstrate a noticeable influence of the volatility of the tin compounds on their signals measured with both techniques. Thus, in agreement with the compound volatility, the highest signals are obtained for tin tetrachloride followed by di-tert-butyltin/monobutyltin and dibutyltin. The sample introduction system exerts an important effect on the amount of solution loading the plasma and, hence, on the relative signals afforded by the tin compounds in ICP–based techniques. Thus, when working with a pneumatic concentric nebulizer, the use of spray chambers affording high solvent transport efficiency to the plasma (such as cyclonic and single pass) or high spray chamber temperatures is recommended to minimize the influence of the tin chemical compound. Nevertheless, even when using the conventional pneumatic nebulizer coupled to the best spray chamber design (i.e., a single pass spray chamber), signals obtained for di-tert-butyltin/monobutyltin and dibutyltin are still around 10% and 30% lower than the corresponding signal for tin tetrachloride, respectively. When operating with a pneumatic microconcentric nebulizer coupled to a 50 °C-thermostated cinnabar spray chamber, all studied organotin compounds provided similar emission signals although about 60% lower than those obtained for tin tetrachloride. The use of an ultrasonic nebulizer coupled to a desolvation device provides the largest differences in the emission signals, among all tested systems.

Workshops in “Construction of Structures I”: A new teaching methodology in the Building Engineering Degree

Both the current economic situation in the construction sector and the continuous normative changes in the building area imply the use of new methodologies to enhance students’ competences in the degree of Building Engineer. The aim of this paper is to present, analyse and discuss the development of constructive workshops as a new teaching methodology used in the subject of Construction of Structures I at the University of Alicante to complement the constructive and technical knowledge acquired by our students and to enhance their communicative and representation skills essential for their professional practice in the future. The used methodology is based on the development of three-dimensional construction details (in groups of 3 or 4 students) to be shown in two A1-pannels exposed in the corridors of the Polytechnic School. Thus, students’ work approaches constructive problems in a global way by discussing simultaneously with teachers and other groups about the most suitable solution on each case. This contribution has multiperspective results and improves criticism of students in different areas, encouraging new learning strategies and active participation. What is more, on-line information and web applications have been used to prepare and organize this kind of workshops, allowing students to use new technologies as a complementary learning methodology. In conclusion, the use of these new workshops in the Degree of Building Engineer stimulates an interactive class versus a traditional lecture where the participative groups´ attitude and the development of oral presentations dissolve the traditional boundaries regarding public communication skills of the students in the Degree.

Structural Analysis with ANSYS on Stone Constructions in the Historical Spanish Heritage

According to the importance of rehabilitation and recovery of Architectural Heritage in the live of people, this paper is aimed to strengthen the traditional methods of stone vaults calculation taking advantage of the technological characteristics of the powerful program ANSYS Workbench. As an example of this, it could find out the possible pathologies that could arise during the construction history of the building. To limit this research, the upper vault of the main chapel of the Santiago parish church in Orihuela -Alicante- is selected as a reference which is a Jeronimo Quijano´s important building work in the XVI century in the Renaissance. Moreover, it is an innovative stone masonry vault that consists of 8 double intercrossed arches with each other and braced by severies. During the seventeenth century there was a lantern in the central cap and it is unknown why it was removed. Its construction could justify the original constructive solution with intercrossed arches that freed the center to create a more enlightened and comfortable presbytery. By similarity with other Quijano’s works, it is considered a small lantern drilling the central spherical cap. It is proposed to carry out a comparative study of it with different architectural solutions from the same period and based on several common parameters such as: a vault of square plant with spherical surround, intercrossed arches, a possible lantern, the dimension of the permitted space, similar states of loads and compact limestone masonry. The three solutions are mainly differentiated by their size and the type of lantern and its comparison lets us know which one is the most resistant and stable. The other two building works maintain some connection with the Quijano's professional scope. It has selected the particular case of the Communion chapel of the Basilica in Elche (a large prismatic lantern with a large cylindrical drum that starts from the own arches and an upper hemispherical dome), for its conservation, its proximity to Orihuela and its implementation during the century XVIII. Finally, a significant Dome Spanish Renaissance complete the selection: a cross vault of the Benavides Chapel of the Saint Francisco Convent in Baeza - Jaén-, designed by Andres of Vandelvira in the sixteenth century (a large hemispherical dome that starts from the own arcs). To simplify the calculation and standardize the work that have to be contrasted, all of them were considered with some similar characteristics: 30 cm constant thickness, the intercrossed arches were specifically analyzed and had identical loads, Young's modulus and Poisson's ratio. Regarding the calculation solutions, in general terms, the compressive stresses predominate, influencing on it the joint collaboration of the filling material on the vault, the vault itself, the thick side walls, the buttresses and the top cover weight . In addition, the three solutions are suitable, being the Orihuela one the safest and the Baeza one the riskiest for its large dimensions. Thus, the idea of intercrossed arches with suitable thickness would allow carry out the heaviest lantern and this would confirm it as a Renaissance architectural typology built in stone.

Improving the photoactivity of bismuth vanadate thin film photoanodes through doping and surface modification strategies

Currently, one of the most attractive and desirable ways to solve the energy challenge is harvesting energy directly from the sunlight through the so-called artificial photosynthesis. Among the ternary oxides based on earth–abundant metals, bismuth vanadate has recently emerged as a promising photoanode. Herein, BiVO4 thin film photoanodes have been successfully synthesized by a modified metal-organic precursor decomposition method, followed by an annealing treatment. In an attempt to improve the photocatalytic properties of this semiconductor material for photoelectrochemical water oxidation, the electrodes have been modified (i) by doping with La and Ce (by modifying the composition of the BiVO4 precursor solution with the desired concentration of the doping element), and (ii) by surface modification with Au nanoparticles potentiostatically electrodeposited. La and Ce doping at concentrations of 1 and 2 at% in the BiVO4 precursor solution, respectively, enhances significantly the photoelectrocatalytic performance of BiVO4 without introducing important changes in either the material structure or the electrode morphology, according to XRD and SEM characterization. In addition, surface modification of the electrodes with Au nanoparticles further enhances the photocurrent as such metallic nanoparticles act as co-catalysts, promoting charge transfer at the semiconductor/solution interface. The combination of these two complementary ways of modifying the electrodes has resulted in a significant increase in the photoresponse, facilitating their potential application in artificial photosynthesis devices.

The Cyprus Presidency: Pragmatism amid European anxiety. CEPS Commentary, 24 January 2013

Despite several daunting obstacles, the low expectations and the high level of apprehension that accompanied the start of the Cyprus Presidency, Thomas Linders and Steven Blockmans find in a new CEPS Commentary that the small, remote and politically divided island nevertheless succeeded in scoring a number of positive results, thanks in part to the country’s pragmatic approach to the job and the perpetual motion of the EU legislature. As a corrective instrument to big state politics in the EU, however, the role of the Presidency remains limited. This underscores the changed nature of the rotating Presidency of the the Council of the EU since the Lisbon Treaty entered into force. Despite several daunting obstacles, the low expectations and the high level of apprehension that accompanied the start of the Cyprus Presidency, this CEPS Commentary by Thomas Linders and Steven Blockmans expresses surprise that the small, remote and politically divided island succeeded in scoring a number of positive results at all, thanks in part to the country’s pragmatic approach to the job

Turkey votes: Part II - Erdoğan reloaded. EPC Commentary, 3 April 2014

On 30 March, Turkey’s ruling Justice and Development Party (AKP) scooped a significant victory in local elections, taking almost 44 percent of the vote despite accusations of corruption, undermining the rule of law, fundamental rights and freedoms. While there have been claims of election fraud and the main opposition party, the Republican People’s Party (CHP), has demanded recounts in several cities including Istanbul and Ankara, it is clear that even allowing for some level of fraud the win was substantial and more than most people expected. Prime Minister Recep Tayyip Erdoğan has reached a juncture. He has two choices: return to the path of democracy after a period of democratic back-sliding which included passing several controversial reforms such as a new internet law which led to the recent banning of Twitter and Youtube; or alternatively he can forge ahead with his much talked of revenge campaign against those he has accused of creating a “parallel state” and conspiring to remove him from power. Given that Erdoğan viewed this election as a referendum on his popularity and leadership there is a serious risk that he will do the latter; using the significant mandate given to him to do whatever he wants, including further cracking down on democracy.

The EU and its Neighbours: Predictions for 2015. CEPS Commentary, 5 January 2015

Against a backdrop of chaos and violence in the EU’s neighbourhood, Steven Blockmans acknowledges that the troubles of 2014 will cast a long, dark shadow over 2015. In this new CEPS Commentary the author attempts to predict some of the EU foreign policy developments that are likely to mark the New Year.

The Legal Status and Influence of Decisions of International Organizations and other Bodies in the European Union. College of Europe Research Paper in Law 01/2014

Introduction. The European Union’s external action is not only defined by its influence on international developments, but also by its ability and the need to respond to those developments. While traditionally many have stressed the EU’s ‘autonomy’, over the years its ‘dependence’ on global developments has become more clear.2 International law has continued to play a key role in, not only in the EU’s external relations, but also in the Union’s own legal order.3 The purpose of this paper is not to assess the role or performance of the EU in international institutions.4 Rather it purports to reverse the picture and focus on a somewhat under-researched topic: the legal status of decisions of international organizations in the EU’s legal order.5 While parts of the status of these decisions relate to the status of international agreements and international customary law, it can be argued that decisions of international organizations and other international bodies form a distinct category. In fact, it has been observed that “this phenomenon has added a new layer of complexity to the already complex law of external relations of the European Union”.6 Emerging questions relate to the possible difference between decisions of international organizations of which the EU is a member (such as the FAO) and decisions of organizations where it is not (irrespective of existing competences in that area – such as in the ILO). Questions also relate to the hierarchical status of these decisions in the EU’s legal order and to the possibility of them being invoked in direct or indirect actions before the Court of Justice. This contribution takes a broad perspective on decisions of international organizations by including decisions taken in other international institutions which do not necessarily comply with the standard definition of international organizations,7 be it bodies set-up by multilateral conventions or informal (transnational / regulatory) bodies. Some of these bodies are relatively close to the EU (such as the Councils established by Association Agreements – see further Section 5 below); others operate at a certain distance. Limiting the analysis to formal international organizations will not do justice to the manifold relationships between the European Union and various international bodies and to the effects of the norms produced by these bodies. The term ‘international decisions’ is therefore used to refer to any normative output of international institutional arrangements.

The Geostrategic Implications of TTIP. CEPS Special Report No. 105/April 2015

This paper analyses the strategic considerations that define the perceived need for transatlantic renewal, and examines the geo-economic impact of the Transatlantic Trade and Investment Partnership (TTIP) on both emerging powers and poorer countries. It argues that TTIP has the potential to be a catalyst for trade liberalisation at the global level, as long as the US and the EU are proactive about making the ‘open architecture’ of TTIP a reality.

The 2015 Greek Referendum. EPIN Commentary No. 24, 3 July 2015

The Greek government called a snap referendum on the proposals advanced by the EU partners and creditor, i.e. the draft Agreement submitted by the EU/IMF to the Eurogroup of 25 June 2015. There has been a major controversy among Greek constitutional lawyers about whether this referendum meets constitutional requirements. No doubt, the constitutional validity of this referendum could be challenged on pure normative terms (nature of the question, time limit); yet this shock call for a referendum appeared as the only political solution for the Greek government facing the dilemma of whether to take the plunge of having five-months of negotiations transformed into a negative-sum game.

The nuclear deal with Iran: Le moment suprême? CEPS Commentary, 16 July 2015

More than two years in the making, the agreement concluded by China, the EU, France, Germany, Russia, the UK and the US with Iran to prevent the ‘weaponisation’ of the latter’s nuclear programme is a big deal. But, cautions Steven Blockmans in this CEPS Commentary, it is not the silver bullet to the normalisation of relations. Implementation will be a tortuous process, fraught with suspicion and friction. Although Europe has been called upon to seize the moment and to shift to a relationship with Iran based on engagement, not containment, the EU and its member states would be better advised not to move beyond their nuclear focus too quickly, but rather to show a sense of duty and loyal cooperation with their international partners by supporting the effective execution of the accord.

The 2015 ENP Review: A policy in suspended animation. CEPS Commentary, 1 December 2015

One year after the Juncker Commission took office, the long-awaited official review of the European Neighbourhood Policy ​(ENP) ​was published ​in November 2015. By prioritising interests over values in increasingly atomised partnerships, the policy ​will now aim for pragmatic realism​ in its dealings with a turbulent neighbourhood​. ​But in the absence of the necessary funding to tackle the region’s multiple crises, and without a strategic vision to guide relations with the neighbours of the EU’s neighbours, the new ENP remains in suspended animation.

The EU deal to avoid Brexit: Take it or leave. CEPS Special Report No. 131/February 2016

Beyond the drama of the European Council summit of 18-19 February 2016, what became clear was the fundamental desire on the part of the leaders of all 28 EU member states to agree a deal on the British government’s demands for a renegotiated settlement on the UK’s relationship within the European Union. The deal has provided David Cameron with the political capital he needed to call a date for the in/out referendum and to lead a campaign for the UK to stay in the EU. Yet, for all the technical reforms packed into it, the deal is neither a crowd pleaser nor a vote winner. It does, however, mark a watershed acknowledgement that EU integration is not a one-directional process of ‘ever closer union’. In this CEPS Special Report, Stefani Weiss and Steven Blockmans analyse the substance of the “Decision of the Heads of State or Government, meeting within the European Council, concerning a New Settlement for the United Kingdom within the European Union” and shed light on its legal character. They contextualise this EU deal to avoid Brexit, and draw on the conclusions reached in a simulation of European Council negotiations between representatives of think tanks in the European Policy Institutes Network (EPIN), conducted by CEPS and the Bertelsmann Stiftung in October 2015.

The Impact of Brexit on the EU’s International Agreements. CEPS Commentary, 15 July 2016

The prospect of Brexit has kicked up a lot of dust around the now famous Article 50 TEU withdrawal procedure, and the form, scope and sequence of the ‘divorce’ and future framework agreements between the EU and the UK.[1] One issue that has received far less attention is whether the international agreements concluded by the EU will continue to apply to the UK after Brexit, and if so, how.