Comprehensive platform for distribution transactiveenergy markets

Reducing the cost of distributed energy resources (DERs) such as renewables, storage,electric vehicles and smart loads is driving their increased connection to distributionsystems. Extracting maximum benefits from DERs require liberalising distribution sys-tems by allowing: (1) a distribution transactive energy market (DTEM) operated by alocal distribution operator (LDO) and (2) peer-to-peer (P2P), peer-to-LDO (P2LDO) andTransmission-to-LDO (T2LDO) type transactions. A DTEM will bring several benefitssuch as: (1) enhanced economic opportunity for DERs, making them more profitable and(2) increased social welfare benefiting both buyers and sellers. To achieve this objective, wedevelop a comprehensive three-phase DTEM platform that provides maximum economicopportunities for DERs and maximises social welfare that benefits all market participants,while considering P2P, P2LDO and T2LDO transactions, for both energy and ancillaryservices. Interaction between bulk electricity market independent system operator (ISO)and LDO controlled DTEM is presented. The DTEM model is implemented as a practi-cal mixed-integer linear programming formulation that includes a network reconfigurationfeature. The DTEM model is studied on three-phase 5-bus and 34-bus systems, demon-strating its effectiveness to settle energy and ancillary service transactions, while obtainingdistribution locational marginal prices. Results show that P2P transactions, when allowed,increase social welfare and increases profitability of DER

Capacity Market for Distribution System Operator – with Reliability Transactions – Considering Critical Loads and Microgrids

Conventional distribution system (DS) asset planning methods consider energy only from transmission systems (TS) and not from distributed energy resources (DER), leading to expensive plans. Newer transactive energy DS (TEDS) asset planning models, built on capacity market mechanisms, consider energy from both TS and DERs, leading to lower-cost plans and maximizing social welfare. However, in both methods the cost of higher reliability requirements for some users are socialized across all users, leading to lower social welfare. In this paper, a novel transactive energy capacity market (TECM) model is proposed for DS asset planning. It builds on TEDS incremental capacity auction models by provisioning for critical loads to bid and receive superior reliability as a service. The TECM model considers these reliability transactions, in addition, to selling energy transactions from TS and DERs, buying energy transactions from loads, and asset upgrade transactions from the network operator. The TECM model allows for islanded microgrids and network reconfiguration to maximize social welfare. The TECM model is assessed on several case studies, demonstrating that it achieves higher social welfare and a lower plan cost

Evaluation of the modified HTK solution in pancreas transplantationdAn experimental model

One of the great challenges in pancreas transplantation is the ischemia reperfusion injury. It is mentioned that free oxygen and/or nitrogen radicals play a prominent role in this phase. To minimize this problem, a modified histidineetryptophan eketoglutarate (HTK) solution that contains modified antioxidants has been developed. Our aim was to evaluate this solution in improving the viability of the pancreas in comparison with standard HTK and University of Wisconsin (UW) solutions in a porcine model of pancreas transplantation

Antibacterial Strategies from the Sea: Polymer-Bound Cl-Catechols for Prevention of Biofilm Formation

Inspired by the amino acid 2-chloro-4,5-dihydroxyphenylalanine (Cl-DOPA), present in the composition of the proteinaceous glue of the sandcastle worm Phragmatopoma californica, a simple strategy is presented to confer antifouling properties to polymer surfaces using (but not releasing) a bioinspired biocide. Cl-Dopamine is used to functionalize polymer materials and hydrogel films easily, to prevent biofilm formation on themThe authors thank Uwe Rietzler from the Max-Planck-Institut für Polymerforschung for the SFM-based thickness measurements

Conceptual Construction through Contextual Modulation : A Case Study of Happiness and Happy

This is a study of the emotion terms happy and happiness conducted in order to identify the possible grounds in which these notions are perceived by the British English speaking speech community and how people use these terms according to their conceptual frameworks. Basically, it is supposed that the terms happy and happiness are very close in their meanings and they imply more or less the same sense from different angles. This prediction, however, is only partly true. Through this study it is found that there is not as much overlap in the meaning of happy and happiness as one would expect

Conceptual Construction through Contextual Modulation : A Case Study of Happiness and Happy

This is a study of the emotion terms happy and happiness conducted in order to identify the possible grounds in which these notions are perceived by the British English speaking speech community and how people use these terms according to their conceptual frameworks. Basically, it is supposed that the terms happy and happiness are very close in their meanings and they imply more or less the same sense from different angles. This prediction, however, is only partly true. Through this study it is found that there is not as much overlap in the meaning of happy and happiness as one would expect

Phenothiazine based polymers for energy and data storage application

Die vorliegende Arbeit befasst sich mit der Synthese und Charakterisierung von Polymeren mit redox-funktionalen Phenothiazin-Seitenketten. Phenothiazin und seine Derivate sind kleine Redoxeinheiten, deren reversibles Redoxverhalten mit electrochromen Eigenschaften verbunden ist. Das besondere an Phenothiazine ist die Bildung von stabilen Radikalkationen im oxidierten Zustand. Daher können Phenothiazine als bistabile Moleküle agieren und zwischen zwei stabilen Redoxzuständen wechseln. Dieser Schaltprozess geht gleichzeitig mit einer Farbveränderung an her.rnrnIm Rahmen dieser Arbeit wird die Synthese neuartiger Phenothiazin-Polymere mittels radikalischer Polymerisation beschrieben. Phenothiazin-Derivate wurden kovalent an aliphatischen und aromatischen Polymerketten gebunden. Dies erfolgte über zwei unterschiedlichen synthetischen Routen. Die erste Route beinhaltet den Einsatz von Vinyl-Monomeren mit Phenothiazin Funktionalität zur direkten Polymerisation. Die zweite Route verwendet Amin modifizierte Phenothiazin-Derivate zur Funktionalisierung von Polymeren mit Aktivester-Seitenketten in einer polymeranalogen Reaktion. rnrnPolymere mit redox-funktionalen Phenothiazin-Seitenketten sind aufgrund ihrer Elektron-Donor-Eigenschaften geeignete Kandidaten für die Verwendung als Kathodenmaterialien. Zur Überprüfung ihrer Eignung wurden Phenothiazin-Polymere als Elektrodenmaterialien in Lithium-Batteriezellen eingesetzt. Die verwendeten Polymere wiesen gute Kapazitätswerte von circa 50-90 Ah/kg sowie schnelle Aufladezeiten in der Batteriezelle auf. Besonders die Aufladezeiten sind 5-10 mal höher als konventionelle Lithium-Batterien. Im Hinblick auf Anzahl der Lade- und Entladezyklen, erzielten die Polymere gute Werte in den Langzeit-Stabilitätstests. Insgesamt überstehen die Polymere 500 Ladezyklen mit geringen Veränderungen der Anfangswerte bezüglich Ladezeiten und -kapazitäten. Die Langzeit-Stabilität hängt unmittelbar mit der Radikalstabilität zusammen. Eine Stabilisierung der Radikalkationen gelang durch die Verlängerung der Seitenkette am Stickstoffatom des Phenothiazins und der Polymerhauptkette. Eine derartige Alkyl-Substitution erhöht die Radikalstabilität durch verstärkte Wechselwirkung mit dem aromatischen Ring und verbessert somit die Batterieleistung hinsichtlich der Stabilität gegenüber Lade- und Entladezyklen. rnrnDes Weiteren wurde die praktische Anwendung von bistabilen Phenothiazin-Polymeren als Speichermedium für hohe Datendichten untersucht. Dazu wurden dünne Filme des Polymers auf leitfähigen Substraten elektrochemisch oxidiert. Die elektrochemische Oxidation erfolgte mittels Rasterkraftmikroskopie in Kombination mit leitfähigen Mikroskopspitzen. Mittels dieser Technik gelang es, die Oberfläche des Polymers im nanoskaligen Bereich zu oxidieren und somit die lokale Leitfähigkeit zu verändern. Damit konnten unterschiedlich große Muster lithographisch beschrieben und aufgrund der Veränderung ihrer Leitfähigkeit detektiert werden. Der Schreibprozess führte nur zu einer Veränderung der lokalen Leitfähigkeit ohne die topographische Beschaffenheit des Polymerfilms zu beeinflussen. Außerdem erwiesen sich die Muster als besonders stabil sowohl mechanisch als auch über die Zeit.rnrnZum Schluss wurden neue Synthesestrategien entwickelt um mechanisch stabile als auch redox-funktionale Oberflächen zu produzieren. Mit Hilfe der oberflächen-initiierten Atomtransfer-Radikalpolymerisation wurden gepfropfte Polymerbürsten mit redox-funktionalen Phenothiazin-Seitenketten hergestellt und mittels Röntgenmethoden und Rasterkraftmikroskopie analysiert. Eine der Synthesestrategien geht von gepfropften Aktivesterbürsten aus, die anschließend in einem nachfolgenden Schritt mit redox-funktionalen Gruppen modifiziert werden können. Diese Vorgehensweise ist besonders vielversprechend und erlaubt es unterschiedliche funktionelle Gruppen an den Aktivesterbürsten zu verankern. Damit können durch Verwendung von vernetzenden Gruppen neben den Redoxeigenschaften, die mechanische Stabilität solcher Polymerfilme optimiert werden. rn rnMy work described in the current thesis is focused on the synthesis and characterization of polymers with phenothiazine pendant moieties. Phenothiazine and its derivatives are small redox units with reversible redox and optical properties. The crucial aspect about phenothiazine is the formation of stable radical cation in the oxidized state. Therefore, phenothiazine derivatives are useful as bistable molecules which can be switched between two stable redox states which in addition are accompanied by a change in color. rnrnWithin the scope of this thesis, the synthetic approach to a new type of phenothiazine polymers by radical polymerization is described. In this context, phenothiazine derivatives were attached to aliphatic and aromatic backbones. Two synthetic routes were studied; one starting from a double bond monomer and the other from an amine containing monomer for post-functionalization with activated ester polymers. Both synthetic routes offer simple and effective approaches to obtain polymers with redox functionality. rnrnPolymers with phenothiazine redox functionality are promising candidates as cathode active materials due to their electron donating properties. In order to prove their applicability and examine their performance, phenothiazine polymers were implemented as electrode material in battery cells. The phenothiazine polymers possess decent charging capacities between 50 and 90 Ah/kg at charging rates 5 to 10 times faster than conventional lithium batteries. With respect to long-term charging and discharging, phenothiazine baring polymers are very robust for over more than 500 charge-discharge cycles. It appeared that the stability depends strongly on the formation and the stabilization of the radical cation which is formed by reversible oxidation of the phenothiazine moieties. Long alkyl spacers between the backbone and the phenothiazine moiety help to stabilize the radical cation species and increase the life time of the battery regarding the number of charge and discharge cycles. rnrnIn addition to applications in batteries the bistability of phenothiazine polymers for high density data storage purposes was studied. Using the conductive mode of scanning force microscopy (SFM), nano-scaled patterning of spin-coated polymer films induced by electrochemical oxidation was successfully demonstrated. The scanning probe experiments revealed differences in the conductive states of written patterns before and after oxidation with no significant change in topography. Remarkably, the patterns were stable with respect to the storage time as well as mechanical wear. rnrnFinally, new synthetic approaches towards mechanically nanowear stable and redox active surfaces were established. Via grafting from methods based on Atom Transfer Radical Polymerization (ATRP), redox active polymer brushes with phenothiazine moieties were prepared and characterized by SFM and X-ray techniques. In particular, a synthetic route based on polymer brush structures with activated ester functionality appeared as a very promising and versatile fabrication method. The activated ester brushes were used for attachment of phenothiazine moieties in a successive step. By using crosslinkable diamine moieties, polymer brushes with redox functionalities and with increased surface wear resistance were successfully synthesized. rnrnIn summary, this work offers deep insights into the electronic properties of polymers with phenothiazine redox active moieties. Furthermore, the applicability of phenothiazine polymers for electronic devices was explored and improved from synthetic polymer chemistry point of view. rn r

Developing a causal model of media literacy based on metacognitive skills, self-regulation learning strategies and self-efficacy with the mediation of creative thinking in students

Background and Aim: Some research has been conducted on the determinant of media literacy. However, this is less done in a causal mode.  Therefore, the aim of this study was to develop a causal model of media literacy based on metacognitive skills, self-regulatory learning strategies and self-efficacy mediated by creative thinking in students. Methods: For this purpose, 318 students of Azad University, North Tehran Branch were selected as the subjects by available sampling method.  Data were collected using the Media Literacy Questionnaire, Wells Metacognitive Skills, Pintrich and De Groot Self-Regulatory Learning Strategies, Schwarzer Self-Efficacy, and Abedi's Creative Thinking. Data were analyzed with the aid of structural equation modeling and AMOS-graphic software. Results: The results showed that the fit of the proposed conceptual model of the research is approved, and all the three predictor variables of metacognitive skills, self-regulated learning strategies and self-efficacy mediated by creative thinking effect on media literacy. Conclusion: The findings of the present study can be used by universities, educational centers, IRIB, cultural centers and other related experts and can play a role in the development and improvement of media literacy

Evaluation of the modified HTK solution in pancreas transplantation—An experimental model

One of the great challenges in pancreas transplantation is the ischemia reperfusion injury. It is mentioned that free oxygen and/or nitrogen radicals play a prominent role in this phase. To minimize this problem, a modified histidine–tryptophan–ketoglutarate (HTK) solution that contains modified antioxidants has been developed. Our aim was to evaluate this solution in improving the viability of the pancreas in comparison with standard HTK and University of Wisconsin (UW) solutions in a porcine model of pancreas transplantation. Twenty-three Landrace pigs were divided into three identical groups. After a 10-hour preservation time at 4°C, the pancreas was implanted in the organs of the recipients in a standardized manner. Serum parameters were assessed prior to and after implantation on the 1st postoperative day, 3rd postoperative day, and 7th postoperative day. Furthermore, three biopsies were taken: prior to and after reperfusion, and on Day 7 to assess the grafts. An analysis of serum glucose among the three groups showed no significant differences. Evaluation of the insulin levels showed no significant difference between the modified and standard HTK groups, however, differences between HTK and UW were significant (p = 0.004 in favor of UW solutions). The histopathological results showed a trend of a higher grade of rejection of pancreas tissue in the UW group compared to both HTK groups. The modified HTK solution could preserve the pancreas for the preservation of the graft with similar results to those observed for standard solutions without any significant difference. The trend showed that the pathological finding in the UW group was not as good as that in the modified HTK and standard HTK groups