Fractionnement simple et multi-étapes à l'urée d'huiles marines du Québec

Diverses fractions d'huiles marines hydrolysées ont été concentrées en certains acides gras grâce à une méthode multi-étape de fractionnement par urée utilisant le méthanol comme solvant. Ces fractions incluent les acides gras saturés (AGS), les mono insaturés (AGMI) et les polyinsaturés à longues chaînes (AGPI) tels que les acides eicosapentaénoïque (AEP), docosapentaénoïque (ADP) et docosahexaénoïque (ADH). Ainsi le but de cette étude était de vérifier les effets du ratio urée/acides gras/méthanol et de la procédure multi-étapes sur les produits finaux. Les données sur la composition en acides gras indiquent que le fractionnement multi-étape par urée est une méthode efficace pour la séparation des fractions d'huiles marines et que cette méthode produit des fractions AGS, AGMI et AGPI fortement concentrées. Après complexion des AGSet des acides gras libres (AGL) à faible insaturation, des concentrations (Cm) de AGPI allant jusqu'à 93,2%, 88,4% et 73,4% ont été obtenues avec les huiles de maquereau, de phoque et d'hareng, respectivement; les ratios AGLlUréelMéthanol étant de 1:3:10 à 3:5:20 à une température de 4°C. Les cristaux formés ont été enrichis en AGS et AGMI. Des valeurs Cm pour les SA de 70,0 59,5 et 50,5% ont été obtenues avec des ratios AGL/Urée/Méthanol de 1:3:10 à 3:5:20 à une température de 4°C; alors que la seconde étape du fractionnement a fourni des valeurs de Cm pour les AGMI de 51,6%, 73,2% et 69,6% pour les huiles de maquereau, phoque et harengs, respectivement, avec des ratios AGL/Urée/Méthanol de 2:1:5 à 3:2:10 à une température de 4°C. L'approche multi-étape développée s'avère donc prometteuse pour la valorisation intégrale des huiles marines

A Cross-layer Perspective on Energy Harvesting Aided Green Communications over Fading Channels

We consider the power allocation of the physical layer and the buffer delay of the upper application layer in energy harvesting green networks. The total power required for reliable transmission includes the transmission power and the circuit power. The harvested power (which is stored in a battery) and the grid power constitute the power resource. The uncertainty of data generated from the upper layer, the intermittence of the harvested energy, and the variation of the fading channel are taken into account and described as independent Markov processes. In each transmission, the transmitter decides the transmission rate as well as the allocated power from the battery, and the rest of the required power will be supplied by the power grid. The objective is to find an allocation sequence of transmission rate and battery power to minimize the long-term average buffer delay under the average grid power constraint. A stochastic optimization problem is formulated accordingly to find such transmission rate and battery power sequence. Furthermore, the optimization problem is reformulated as a constrained MDP problem whose policy is a two-dimensional vector with the transmission rate and the power allocation of the battery as its elements. We prove that the optimal policy of the constrained MDP can be obtained by solving the unconstrained MDP. Then we focus on the analysis of the unconstrained average-cost MDP. The structural properties of the average optimal policy are derived. Moreover, we discuss the relations between elements of the two-dimensional policy. Next, based on the theoretical analysis, the algorithm to find the constrained optimal policy is presented for the finite state space scenario. In addition, heuristic policies with low-complexity are given for the general state space. Finally, simulations are performed under these policies to demonstrate the effectiveness

Coalitional Game Theoretic Approach for Cooperative Transmission in Vehicular Networks

Cooperative transmission in vehicular networks is studied by using coalitional game and pricing in this paper. There are several vehicles and roadside units (RSUs) in the networks. Each vehicle has a desire to transmit with a certain probability, which represents its data burtiness. The RSUs can enhance the vehicles' transmissions by cooperatively relaying the vehicles' data. We consider two kinds of cooperations: cooperation among the vehicles and cooperation between the vehicle and RSU. First, vehicles cooperate to avoid interfering transmissions by scheduling the transmissions of the vehicles in each coalition. Second, a RSU can join some coalition to cooperate the transmissions of the vehicles in that coalition. Moreover, due to the mobility of the vehicles, we introduce the notion of encounter between the vehicle and RSU to indicate the availability of the relay in space. To stimulate the RSU's cooperative relaying for the vehicles, the pricing mechanism is applied. A non-transferable utility (NTU) game is developed to analyze the behaviors of the vehicles and RSUs. The stability of the formulated game is studied. Finally, we present and discuss the numerical results for the 2-vehicle and 2-RSU scenario, and the numerical results verify the theoretical analysis.Comment: accepted by IEEE ICC'1

Charging Scheduling of Electric Vehicles with Local Renewable Energy under Uncertain Electric Vehicle Arrival and Grid Power Price

In the paper, we consider delay-optimal charging scheduling of the electric vehicles (EVs) at a charging station with multiple charge points. The charging station is equipped with renewable energy generation devices and can also buy energy from power grid. The uncertainty of the EV arrival, the intermittence of the renewable energy, and the variation of the grid power price are taken into account and described as independent Markov processes. Meanwhile, the charging energy for each EV is random. The goal is to minimize the mean waiting time of EVs under the long term constraint on the cost. We propose queue mapping to convert the EV queue to the charge demand queue and prove the equivalence between the minimization of the two queues' average length. Then we focus on the minimization for the average length of the charge demand queue under long term cost constraint. We propose a framework of Markov decision process (MDP) to investigate this scheduling problem. The system state includes the charge demand queue length, the charge demand arrival, the energy level in the storage battery of the renewable energy, the renewable energy arrival, and the grid power price. Additionally the number of charging demands and the allocated energy from the storage battery compose the two-dimensional policy. We derive two necessary conditions of the optimal policy. Moreover, we discuss the reduction of the two-dimensional policy to be the number of charging demands only. We give the sets of system states for which charging no demand and charging as many demands as possible are optimal, respectively. Finally we investigate the proposed radical policy and conservative policy numerically

Collaborative Learning for Information Security Topics: A Pilot Study

Collaborative learning has seen a growing popularity in computing education with promising results. The purpose of this research study is to determine if the collaborative guided learning pedagogy is valid for the diverse information security-related topics. We have developed and tested on three security topics and learning activities, including input validation, security in operating systems, and SQL injection in the pilot study. Applied pre-test and post-test surveys to measure the effectiveness of the learning experiences. We have conducted statistical analysis and qualitative analysis to compare the pre- and post-surveys results. Furthermore, we found that team experience is helpful to research with security topics, and more time allowed for the activity could benefit the learning experience

The Effectiveness of a Hybrid Cybersecurity Summer Camp for Teachers

Cybersecurity teacher education plays a vital role in narrowing the gap in the need for cybersecurity professionals in the workforce. In this paper, the authors examined the effectiveness of a hybrid cybersecurity summer camp for secondary education in-service teachers. The pre- and post-camp quizzes showed significant statistical difference, t(17) = -8.42, p \u3c .001, with a large effect size of 2.24. Focus group interviews with the teacher participants further suggested that the hybrid modality is not only viable but also a preferred format welcomed by the teachers

Effectiveness of Bridging Master Program in Cybersecurity and Industry in US: Program Comparison and Analysis

This paper aims to investigate the existing curriculum of cybersecurity programs the U.S. universities and provide suggestions to improve the programs to fill the gap between academia and industry. In the current state of science and technology, the need for strengthening cyber security has been increasingly growing in every developed country and transforming it into one of the most critical sectors of society. In this research, we have shown the essential role of cybersecurity professionals in preventing, detecting, responding to, and mitigating cyber-attacks using a case study of a targeted cyber-attack of a large organization. We presented a threat-centric framework for developing cybersecurity competencies and detailing the steps involved in building a cybersecurity master\u27s program. Consequently, we have made some suggestions regarding a holistic approach to address these issues. This paper is intended to prepare students for careers and research in cybersecurity and related areas

Oxidation of some Main Group elements and their low oxidation state compounds by substituted o-benzoquinones.

This work was undertaken to further develop work carried out in this laboratory in recent years on the oxidation of Main Group 3A and 4A elements, and of compounds of these elements in low oxidation states, by focusing on the oxidation of the Main Group 5A and 6A elements phosphorus, tellurium and antimony, and of their low oxidation states compounds. The phosphorus compounds P(O\rm\sb2C\sb6R)\sb2Br (R = Cl\sb4, Br\sb4 or Bu\rm\sp t\sb2H\sb2) have been prepared by the reaction of P\sb4, Br\sb2 and the substituted o-benzoquinone o-O\sb2C\sb6R. There is no reaction between o-O\rm\sb2C\sb6Bu\sp t\sb2H\sb2 (dbbq), P\sb4 and Ph\rm\sb2Se\sb2, but in the presence of catalytic quantities of Br\sb2 the product is P(dbc)\sb2(SePh) (dbc = 3,5-di-Bu\sp{\rm t}catecholate). Electron spin resonance (ESR) spectra identify the presence of the corresponding o-semiquinone species in these reactions. The \sp{13}C and \sp{31}P NMR spectra of these phosphoranes are studied and compared with those of P(O\rm\sb2C\sb6R)X\sb3 (X\sb3 = Ph\sb3, Ph\sb2Cl, Br\sb3 or Cl\sb3) prepared by the reaction of PX\sb3 and o-O\rm\sb2C\sb6R. The oxidation of elemental tellurium by three o-benzoquinones o-O\rm\sb2C\sb6R (R = Cl\sb4, Br\sb4 or Bu\rm\sp{t}\sb2H\sb2) is a direct route to the corresponding tellurium(IV) catecholates Te(O\rm\sb2C\sb6R)\sb2. The analogous reaction with organotellurium(II) TeR\sp\prime\sb2, (R\sp\prime\sb2 = Et\sb2, Me\sb2, Ph(Et) or Ph(Br)) gives the products Te(O\rm\sb2C\sb6R)R\sp\prime\sb2. The reactions proceed in each case by one-electron transfer, since the presence of the semiquinone radical O\rm\sb2C\sb6R in the reaction mixture has been demonstrated by ESR spectroscopy. The Te(O\rm\sb2C\sb6R)\sb2 species resist further oxidation, and also show weak donor and acceptor properties. The structure of the compounds Te(dbc)\sb2(bipy) 3.1 and Te(O\rm\sb2C\sb6Cl\sb4)\sb2(18-crown-6) 3.2 have been determined by X-ray crystallography. In both structures, the average Te-O distances (2.012 and 2.015 A respectively) are typical of tellurium(IV) compounds, and the average C-O distances (1.370 and 1.34 A respectively) confirm that the ligands are aromatic diolates. The oxidation of elemental antimony by the tetrahalogeno-o-benzoquinones o-O\rm\sb2C\sb6R (R = Cl\sb4, or Br\sb4) in diethyl ether gives the unusual antimony(v) products Sb(O\rm\sb2C\sb6R)\sb{2.5} \cdot nEt\sb2O (R = Cl\sb4, n = 1.5; R = Br\sb4, n = 1). The same o-benzoquinones, and dbbq, upon treatment with Sb + 1/2X\sb2 (X = Br or I) in diethyl ether, give the antimony(III) derivatives Sb(O\rm\sb2C\sb6R)X (R = Cl\sb4, Br\sb4 or Bu\rm\sp t\sb2H\sb2). The oxidations are shown by ESR spectroscopy to proceed via the o-semiquinone intermediates. Adducts of Sb(O\rm\sb2C\sb6R)I with bidentate neutral donors have been prepared. The structure of Sb(dbc)I(bipy) 4.1 has been shown to be that of a pseudo-octahedral molecule with a stereochemically active lone pair of electrons. The reactions between diphenyl ditelluride and tetrahalogeno-o-benzoquinones o-O\rm\sb2C\sb6X\sb4 (X = Cl or Br) give ((X\rm\sb4C\sb6O\sb2)TeC\sb6H\sb5\rbrack\sb2O. The structure of ((Cl\rm\sb4C\sb6O\sb2)TeC\sb6H\sb5\rbrack\sb2O 5.1 has been established crystallographically. The reactions between Ph\rm\sb2Te\sb2 and other oxidants have also been studied. Preliminary results are also presented on the reaction between o-quinones with tin, and with tin dichloride, as well as the preparation of a novel Schiff-base biquinone lead(II) complex Ph(Cat-N-BQ)\sb2 (Cat-N-Bq = 3,5-di-Bu\sp{\rm t}-1,2-quinone 1-(2-hydroxy-3,5-di-Bu\sp{\rm t}phenyl) 7.1. The structure of 7.1 has been determined by X-ray crystallography. It shows significantly different features in comparison with the known structures of transition metal elements with the same ligand. (Abstract shortened by UMI.)Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1993 .T533. Source: Dissertation Abstracts International, Volume: 55-05, Section: B, page: 1843. Adviser: D. G. Tuck. Thesis (Ph.D.)--University of Windsor (Canada), 1993