Optimizing output regulation for a class of underactuated LPV systems

@ 2017 IEEE. Personal use of these materials is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating news collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other worksIn this paper the problem of optimizing the output regulation of an underactuated LPV system is considered. When the system is underactuated, only a subset of the outputs can be arbitrarily controlled, and the remaining ones are constrained. The problem of finding the input that minimizes a cost function of the overall output tracking error is investigated for a special class of LPV systems that admit steady-states. Moreover, it is shown how such solution is related to the inputs associated to the singularly optimal regulation of each output.Peer ReviewedPostprint (author's final draft

Simultaneous recovery of cellulose and other value-added compounds from orange waste & Synthesis of spiro and ureidic compounds for modulation studies of mptp protein

This thesis is divided in two separate sections, both conducted in the Department of Chemical and Pharmaceutical Sciences under the supervision of Prof. Dr. Simonetta Benetti and Prof. Dr. Claudio Trapella. The first project aimed to demonstrate the opportunity of utilizing a new type of citrus waste, called decanter centrifuge orange waste (DCOW), to extract cellulose and other constituents of the matrix. These could be sold as either mixture or isolated compounds (or derivatives) thus avoiding environmental dangerous waste disposal. A sequence of extraction steps and pH-dependant treatments were studied in order to isolate five different products from DCOW. The choice of the solvents used for extraction was directed by economic issues as well as by the need to attain food-grade compounds. An acidic treatment was utilized in order to isolate a pectic fraction, while a basic treatment allowed purifying the cellulose fraction. α-Cellulose was successfully isolated (with a yield of 9.81% ± 0.25 on dry basis) and used to produce cellulose acetate, a well-known commercial product. The other isolated fractions were analytically characterized and consisted of polyphenols, carbohydrates and terpenes, which represent all high-value products whose further purification may results in appealing saleable products. The second project was intended to synthesize potential inhibitors of mitochondrial permeability transition pore (mPTP) complex opening, which is known to be responsible for ischemic-reperfusion injury (IRI). Up to now, only few compounds are known to directly inhibit this complex. Of them, dicyclohexylcarbodiimide (DCC) and oligomycin A were elected as drug design starting points. Since DCC is slowly hydrated in human body to form dicyclohexylurea (DCU), the latter was chosen as the real starting reference substrate for the synthesis of the target compounds. Therefore, symmetric and asymmetric ureas and thioureas were produced. Besides, some aliphatic carbamate derivatives were synthesized to better understand the influence of the rings adjacent to the carbonyl group on biological activities. Studies were also conducted to synthesize new spiro compounds mimicking oligomycin A structural core. In this case, 1-phenyl-1, 3, 8-triaza-spiro[4,5]decan-4-one template was used to produce the corresponding N-8 substituted derivatives. Almost all these derivatives were produced in reasonably high yields, using inexpensive reagents and under rather mild reaction conditions. Noticeably, preliminary results from biological characterization showed that these derivatives have both inhibitor and activator potency against mPTP opening. While the identified inhibitors may be useful for IRI treatments, alternative use of the activators as antitumor compounds was hypothesized.Questa tesi è divisa in due progetti distinti, entrambi condotti al Dipartimento di Chimica e Scienze Farmaceutiche e sotto la supervisione della professoressa Simonetta Benetti e del professor Claudio Trapella. Il primo progetto mira a dimostrare l’opportunità di utilizzare un nuovo tipo di rifiuto agrumicolo, chiamato residuo d’arancia della centrifuga decanter (decanter centrifuge orange waste – DCOW), per estrarre la cellulosa e altri costituenti presenti all’interno matrice organica. Quest’ultimi potrebbero essere venduti sia come miscele complesse che come composti purificati (o derivati), al fine di ridurre l’impatto ambiente derivante dal progressivo deposito dello scarto agrumicolo. Sono stati studiati differenti approcci al problema, tra cui una sequenza di estrazioni con solventi organici e trattamenti a differente pH al fine di isolare cinque differenti frazioni. I solventi utilizzati durante le estrazioni sono stati selezionati tenendo in considerazione l’ipotetico costo industriale e la necessità di ottenere dei composti che potessero essere destinati anche ad un uso alimentare. Un trattamento acido è stato invece necessario per rimuovere ed isolare una frazione pectica, mentre il trattamento basico ha permesso di purificare la frazione cellulosica. Infine, l’α-cellulosa ottenuta (con una resa del 9.81 % ± 0.25 rispetto al peso secco della matrice) è stata utilizzata per produrre l’acetato di cellulosa, un noto prodotto di interesse commerciale. Nelle altre frazioni isolate, caratterizzate dal punto di vista analitico, è stata riscontrata la presenza di polifenoli, carboidrati e terpeni, tutti composti ad alto valore aggiunto, la cui purificazione potrebbe essere considerata, in futuro, per ottenere ulteriori prodotti di interesse commerciale. Il secondo progetto è stato indirizzato alla sintesi di potenziali inibitori dell’apertura del poro di transizione di permeabilità mitocondriale (mPTP), che è noto per essere responsabile dai danni da ischemia-riperfusione. Fino a questo momento, si conoscono solo pochi composti in grado di inibire questo complesso proteico. Tra questi sono presenti la dicicloesilcarbodiimmide (DCC) e l’oligomicina A le cui strutture sono state prese come punti di partenza per la costruzione dei nuovi inibitori. Poiché la DCC all’interno del corpo umano è lentamente idratata a dicicloesilurea (DCU), quest’ultima è stata selezionata come principale riferimento per la sintesi dei targets. Per questo motivo sono state sintetizzate differenti uree e tiouree simmetriche e asimmetriche. Inoltre sono stati sintetizzati due derivati carbammici per meglio comprendere l’importanza biologica di strutture cicliche adiacenti al gruppo carbonile. Per quanto riguarda la struttura dell’oligomicina A, si è optato per sintetizzare delle nuove molecole che possedessero uno spiro centro, come nel caso dell’oligomicina, ma che permettessero delle modifiche strutturali su più parti della molecola. In questo caso si è scelto l’1-fenil-1,3,8-triaza-spiro[4,5]decan-4-one, un composto commercialmente disponibile, per produrre i corrispettivi derivati sull’atomo di azoto in posizione 8. Quasi tutti i derivati sono stati sintetizzati con rese moderatamente alte, utilizzando reagenti economici e in condizioni di reazione blande. Inaspettatamente, i risultati preliminari provenienti da test biologici in vitro hanno mostrato che alcuni dei prodotti sintetizzati sembrano buoni inibitori, mentre altri sono risultati induttori dell’apertura dell’mPTP. Questi ultimi, nonostante non possano essere utilizzati nel campo del trattamento da IRI, potrebbero possedere un efficacia come composti anti-tumorali

Some remarks on optimal output regulation for weakly dual redundant plants

In this paper the problem of optimizing the output regulation of a weakly dual redundant plant is addressed. When the system is under-actuated, only a subset of the outputs can be arbitrarily controlled, and the remaining ones are constrained. We investigate the problem of finding the input that minimize a cost function of the overall output tracking error, and how such solution is related to the inputs associated to the singularly optimal regulation of each output. Some interesting properties are revealed, such as the optimal solution being always included in the convex hull of singularly optimal controls and the existence of neutral reference spaces

Optimally controlled steady-states for multi-input underactuated linear systems

In this paper the problem of optimizing the regulation of a weakly dual redundant plant with multiple actuators is addressed. When the system is underactuated, only a subset of the outputs can be independently controlled. In this regard, the main objective of the paper pertains the optimization of the steady-state performance of the plant. A connection between the overall optimal input and the inputs that provide a perfect reference tracking of the full controllable square subsystems is established. The proposed control scheme is validated by the simulation experiment of a tracking problem for a three mass coupled system