Mineral carbonation contributes to CO2 reduction, and it may also reduce the cost of mineral processing by improving the mechanical properties of rock/ore. Here, we study and compare the mechanical properties of two minerals, forsterite (Mg2SiO4) and magnesite (MgCO3) using molecular dynamics (MD) simulation. The goal is to understand whether carbonation results in hardness reduction of rock and subsequently comminution energy during the crushing and processing of the ore. We investigated how these materials respond to different physical conditions, such as temperature and strain rate, to understand their behavior under stress. By examining the molecular structure of forsterite and magnesite at temperatures ranging from 300K to 700K and strain rates of 0.001, 0.01, and 0.05ps-1, we observed how they deform when subjected to both tensile and compressive forces. This study has shown that at higher temperatures, both forsterite and magnesite monocrystals undergo deformation more easily under pressure. Forsterite is found relatively hard and shows maximum strength before deformation compared to magnesite. The stiffness of magnesite decreases at elevated temperatures which reduces the energy requirement for the comminution process. We also looked at how pressure and temperature changes affected their elasticity. Ultimately, our findings suggest that magnesite may be more suitable for processes like comminution, which involves breaking down materials, compared to forsterite. This insight into the effects of mineral carbonation on geomaterials contributes to our understanding of how these minerals behave under different conditions and could have implications for various industries. / Master of Science / Mineral carbonation contributes to CO2 reduction, and it may also reduce the cost of mineral processing by improving the mechanical properties of rock/ore. Here, we study and compare the mechanical properties of two minerals, forsterite (Mg2SiO4) and magnesite (MgCO3) using molecular dynamics (MD) simulation. The goal is to understand whether carbonation results in hardness reduction of rock and subsequently comminution energy during the crushing and processing of the ore. We investigated how these materials respond to different physical conditions, such as temperature and strain rate, to understand their behavior under stress. By examining the molecular structure of forsterite and magnesite at temperatures ranging from 300K to 700K and strain rates of 0.001, 0.01, and 0.05ps-1, we observed how they deform when subjected to both tensile and compressive forces. This study has shown that at higher temperatures, both forsterite and magnesite monocrystals undergo deformation more easily under pressure. Forsterite is found relatively hard and shows maximum strength before deformation compared to magnesite. The stiffness of magnesite decreases at elevated temperatures which reduces the energy requirement for the comminution process. We also looked at how pressure and temperature changes affected their elasticity. Ultimately, our findings suggest that magnesite may be more suitable for processes like comminution, which involves breaking down materials, compared to forsterite. This insight into the effects of mineral carbonation on geomaterials contributes to our understanding of how these minerals behave under different conditions and could have implications for various industries.

This aim of this thesis is to contribute to the debate about the best approach to engage citizens with sustainable behaviour. It is generally agreed that „bottom-up‟ approaches, where individuals are actively involved, are more effective than „top-down‟ authority-led projects where they have a more passive role. There is, however, a dearth of evidence from comparative evaluations. This thesis examines six distinct communication activities aimed at encouraging individuals to adopt more sustainable behaviours. Each used a different approach, some participative and others more top-down informational. Two questionnaires were used to gather data. The first was conducted at the time of the activity; the second between four and five weeks later and included questions about behaviour change. Variables from Petty and Cacioppo‟s Elaboration Likelihood Model (ELM), such as perceptions about a message and its source, and variables which Ajzen‟s Theory of Planned Behaviour (TPB) proposes as being key to behaviour change, such as subjective norms and attitudes, were used to see if these identified any difference in outcome. Findings indicate support for the added value of a bottom-up approach compared to other mechanisms and identify that this may be partly explained by the extent to which such activities offer a more supportive environment for behaviour change to take place. The measures used in this study may be useful to others seeking to evaluate behaviour change communication campaigns or those comparing different communicative approaches.

<p>U bežičnoj mreži senzora i robota, senzorski moduli vrše nadzor<br />fizičkih veličina od značaja, a roboti imaju ulogu izvršilaca<br />zadataka koji im se dodeljuju primenom odgovarajućeg algoritma. Nakon<br />detekcije događaja od strane statičkih senzorskih čvorova i<br />prosleđivanja informacija o događajima robotima, potrebno je<br />dodeliti zadatke robotima na efikasan način. Dodela zadataka vrši<br />se u skladu sa prirodom različitih scenarija koji se mogu javiti u<br />praksi. U okviru disertacije razmatran je slučaj kada se konkurentno<br />javlja više događaja kojima je potrebno dodeliti izvršioce. U pogledu<br />energetske efikasnosti, u ovakvim sistemima kao ključni problemi<br />javljaju se minimizacija ukupne dužine kretanja robota i optimizacija<br />komunikacije u mreži. Od komunikacinih protokola za otkrivanje<br />izvršilaca, u ovoj disertaciji predstavljena su poboljšanja<br />postojećeg iMesh protokola i uveden je novi vCell protokol zasnovan na<br />lokalizovanom formiranju ćelija Voronoi dijagrama. Takođe,<br />upoređene su performanse novog protokola sa postojećim (pravougaoni<br />kvorum i iMesh) u gustim mrežama, retkim mrežama i mrežama sa<br />rupama u topologiji. Uz to, uvedeni su algoritmi za ažuriranje lokacije<br />kojima mreža reaguje na kretanje robota. Rezultati simulacija pokazuju<br />da vCell postiže efikasnost blizu 100% u nalaženju najbližeg robota u<br />gustim mrežama. U retkim mrežama, efikasnost mu je do 40% bolja u<br />odnosu na ostala rešenja.</p><p>Kao glavni rezultat u disertaciji prikazani su novi algoritmi za<br />dodelu robota kao izvršilaca zadataka događajima, čime su<br />prevaziđni nedostaci više do sada poznatih rešenja ovog problema.<br />Za zadati skup događaja i skup robota, svakom događaju dodeljen je po<br />jedan robot koji je zadužen za obilazak lokacije događaja. Tokom<br />pojedinačnih rundi, robotima je dozvoljen obilazak jednog događaja<br />kada se vrši uparivanje, ili više događaja, kada se vrši<br />sekvencijalna dodela. U distribuiranom slučaju, statički senzorski<br />uređaji detektuju događaje i prijavljuju ih obližnjim robotima.<br />Algoritam PDM koji se odnosi na unapređeno uparivanje sa mogućnošću<br />razmene partnera, eliminiše dugačke ivice koje se mogu javiti<br />prilikom uparivanja. Algoritam SQD za sekvencijalnu dodelu događaja<br />robotima iterativno pronalazi par robot-događaj sa najmanjim<br />međusobnim rastojanjem, uvrštava izabrani događaj u listu za oblazak<br />izabranog robota i ažurira poziciju robota. Takođe su predložene<br />generalizacije koje omogućavaju da događaji budu posećeni od strane<br />više robota i koje uzimaju u obzir vremenska ograničenja.<br />Distribuirani algoritam MAD, koji je zasnovan na iMesh<br />informacionoj strukturi i lokalnim aukcijama u robotskoj mreži,<br />vrši dodelu robota događajima na lokalizovan i energetski efikasan<br />način. Rezultati simulacija potvrđuju prednosti predloženih<br />algoritama u odnosu na postojeća rešenja, kako u pogledu skraćivanja<br />dužina putanja robota, tako i u produženju životnog vremena sistema.</p> / <p>In a typical wireless sensor and robot network, sensor nodes monitor physical<br />values of interest, while robots perform some automated tasks. The tasks are<br />assigned to robots by means of an appropriate algorithm. Upon the<br />occurrence of events which are detected by sensor nodes, the information<br />about the events needs to be delivered to robots. Afterwards, it is necessary<br />to assign tasks to robots in an efficient way. Task assignment is performed<br />according to the nature of different scenarios which might occur in practice.<br />This thesis is focused on the case when multiple events, all of which require<br />to be visited by robots, happen simultaneously. Regarding energy efficiency,<br />the key issues which arise in such systems are minimization of robot travel<br />paths, and optimization of the network traffic. In this thesis, the following<br />service discovery protocols are presented: improvements of the existing<br />iMesh protocol, and the novel vCell protocol, which is based on localized<br />formation of an information structure which resembles Voronoi diagram.<br />Furthermore, the performaces of new vCell protocol is compared with the<br />existing protocols (Quorum and iMesh) in dense networks, sparse networks,<br />and networks with holes in topology. Also, location update algorithms are<br />introduced, which deal with robot mobility. The simulations show that vCell<br />achieves nearly 100% success rate in finding the nearest robot in dense<br />networks. In sparse networks, it outperforms the other existing solutions by up<br />to 40%.<br />As a key contributtion, the novel dispatch lgorithms have been introduced.<br />Given a set of events and a set of robots, the dispatch problem is to allocate<br />one robot for each event to visit it. In a single round, each robot may be<br />allowed to visit only one event (matching dispatch), or several events in a<br />sequence (sequence dispatch). In a distributed setting, each event is<br />discovered by a sensor and reported to a robot. In this thesis, novel<br />algorithms are presented, whichh are aimed at overcoming the shortcomings<br />of several existing solutions. Pairwise distance based matching algorithm<br />(PDM) eliminates long edges by pairwise exchanges between matching pairs.<br />Sequence dispatch algorithm (SQD) iteratively finds the closest event-robot<br />pair, includes the event in dispatch schedule of the selected robot and<br />updates its position accordingly. When event-robot distances are multiplied by<br />robot resistance (inverse of the remaining energy), the corresponding energybalanced<br />variants are obtained. Also, generalizations are introduced which<br />handle multiple visits and timing constraints. Distributed algorithm MAD is<br />based on information mesh infrastructure and local auctions within the robot<br />network for obtaining the optimal dispatch schedule for each robot. The<br />simulations conducted confirm the advantages of our algorithms over other<br />existing solutions in terms of average robot-event distance and lifetime.</p>