Orientador: Edvaldo Sabadini / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-18T08:47:56Z (GMT). No. of bitstreams: 1 Ito_ThiagoHeiji_M.pdf: 9507666 bytes, checksum: 9c5cb27aa349ff6d08d87d4e89723fb2 (MD5) Previous issue date: 2011 / Resumo: A formação, estabilidade e aplicações das micelas gigantes têm sido amplamente estudadas. Estes sistemas são muito interessantes devido ao seu comportamento reológico similar aos polímeros. Porém, as micelas gigantes são espécies supramoleculares mantidas por ligações não-covalentes, portanto, sob alta turbulência, podem resistir à degradação mecânica, além de promoverem redução de atrito hidrodinâmico devido ao efeito Toms. Neste estudo, a formação e estabilidade das micelas gigantes formadas pela combinação de surfatantes catiônicos e diferentes compostos aromáticos, foram estudadas sistematicamente. A redução de atrito foi observada medindo o torque aplicado à solução para manter a turbulência. A temperatura do sistema foi progressivamente aumentada, mostrando o ponto específico em que as micelas gigantes são termicamente destruídas. Baseado neste estudo foi possível estabelecer a ordem em termos de estabilidade: ácido orto-hidróxicinâmico (OHCA) ~ salicilato > tosilato > ácido orto-metóxi-cinâmico (OMCA) > fenol. Para benzoato e metóxibenzoato não foi observada a formação de micelas gigantes. Estes resultados revelam algumas interações peculiares entre a cabeça do surfatante e a molécula aromática. Em regimes semidiluídos, começa haver entrelaçamentos das macroestruturas, formando géis de Maxwell, assim, a reologia oscilatória foi usada para determinar G¿, G¿ e o tempo de relaxação em função da frequência. Apesar de G0 ser praticamente o mesmo, o tempo de relaxação parece ser sensível à composição de co-soluto, seguindo a seguinte ordem: fenol < OMCA < tosilato < OHCA ~ salicilato. Experimentos de calorimetria e espalhamento de luz também foram utilizados para corroborar com os experimentos de reologia / Abstract: The formation, stability and applications of worm-like micelles have been widely studied. These systems are very interesting because their rheological behavior is similar to the polymeric one. However, the worm-like micelles are supramolecular species maintained by non-covalent bonds, thus, upon high turbulence, they resist to mechanical degradation, besides, they promote the drag reduction due to Toms Effect. In this study, the formation and stability of worm like micelles formed by the combination of cationic surfactants and different aromatic compounds were systematically studied. The drag reduction was observed by measuring the torque applied to the solution to maintain the turbulence. The system temperature was then progressively enhanced, revealing the specific point in which the worm-like micelles are thermally destroyed. Based in such study it was possible to establish the order in terms of stability: orthohydroxycinnamic acid (OHCA) ~ salycilate > tosylate > orthomethoxycinnamic acid (OMCA) > phenol. For benzoate and methoxybenzoate, no worm-like micelles are observed. These results reveal some peculiar interactions between the head of the surfactant and the aromatic molecules. In more concentrated regime, chains of the wormlike micelles undergo entanglements, forming typical Maxwell gels. The oscillatory rheology was used to determine G¿, G¿ and the relaxation time as a function of the frequency. Although G0 is practically the same, the relaxation time is quite sensitive to the composition of the co-solute, following order: phenol < OMCA < tosylate < OHCA ~ salycilate. Calorimetric and light scattering experiments were carried out to corroborate the rheological experiments / Mestrado / Físico-Química / Mestre em Química

Hundreds of millions of people use their home computers every day for different purposes. Many of them are connected to the Internet. Most of them are unaware of the threats or do not know how to protect themselves. This unawareness is a major threat to global computer security. This master thesis starts by explaining some security related terms that might be unknown to the reader. It then goes on by addressing security vulnerabilities and flaws in the most popular home computer operating systems. The most important threats to home computer security are reviewed in the following chapter. These threats include worms, email worms, spyware and trojan horses. After this chapter some possible solutions for improving home computer security are presented. Finally this master thesis contains a short user survey to find out what the problems are in the real world and what can be doneto improve the current situation.

The terms and classification schemes used in the computer security field today are not standardised. Thus the field is hard to take in, there is a risk of misunderstandings, and there is a risk that the scientific work is being hampered. Therefore this report presents a proposal for a taxonomy of software based IT weapons. After an account of the theories governing the formation of a taxonomy, and a presentation of the requisites, seven taxonomies from different parts of the computer security field are evaluated. Then the proposed new taxonomy is introduced and the inclusion of each of the 15 categories is motivated and discussed in separate sections. Each section also contains a part briefly outlining the possible countermeasures to be used against weapons with that specific characteristic. The final part of the report contains a discussion of the general defences against software weapons, together with a presentation of some open issues regarding the taxonomy. There is also a part discussing possible uses for the taxonomy. Finally the report is summarised.

The thesis examines control and eradication of Guinea worm in West Africa and investigates factors, especially water supply, related to the incidence of Guinea worm. The study was carried out in North Zou, Benin between 1987 and 1990 and in Nigeria between 1989 and 1993 during water supply and Guinea worm eradication programme execution. About 5% of villages in Nigeria, located in one half the LGAs were infected. The number of annual cases in a region was related to the previous year's cases, although 5-10% of the regions changed between infected and non-infected. Cases were not statically focused in villages. The relative risk of infection in a village based on the previous year's infection was 1.74 in North Zou. Incidence varied inversely and endemicity varied directly with village population. Villages of all sizes were infected. Prevalence varies seasonally by region. Incidence was low at high altitudes, in sandy and alluvial soils, in areas with high or low annual rainfall and in densely populated areas. Incidence was not otherwise related to rainfall, vegetation, altitude, soils, geology or distance to rivers. Incidence among Muslims and Christians was the same but varied by ethnic group. Incidence in an area was strongly related to the ratio of females to males. School attendance in endemic areas fell during the transmission period. Losses in Nigeria in 1990/91 were £16 million. Provision of improved water supply lowered incidence by 50%. Endemicity was 20% lower in villages in North Zou with water supply but endemicity did not fall immediately following provision and a difference was not seen in Nigeria. Water supply to all infected villages in Nigeria identified in 1990/91 would cost £23 million. Three possible water supply strategies were examined. Ten water supply options were considered and roof rainwater catchment was found the most promising. Factors that reduce the effective use of water supply were examined. Water supply coverage in endemic countries is 27%. The countries are among the poorest and least developed in the world. The lack of static focus of cases in villages, the low impact of water supply, and the difficulty of supplying water to all endemic areas make Guinea worm eradication by 1999 unlikely.

In this research, a security architecture based on the feedback control theory has been proposed. The first loop has been designed, developed and tested. The architecture proposes a feedback model with many controllers located at different stages of network. The controller at each stage gives feedback to the one at higher level and a decision about network security is taken. The first loop implemented in this thesis detects one important anomaly of virus attack, rate of outgoing connection. Though there are other anomalies of a virus attack, rate of outgoing connection is an important one to contain the spread. Based on the feedback model, this symptom is fed back and a state model using queuing theory is developed to delay the connections and slow down the rate of outgoing connections. Upon implementation of this model, whenever an infected machine tries to make connections at a speed not considered safe, the controller kicks in and sends those connections to a delay queue. Because of delaying connections, rate of outgoing connections decrease. Also because of delaying, many connections timeout and get dropped, reducing the spread. PID controller is implemented to decide the number of connections going to safe or suspected queue. Multiple controllers can be implemented to control the parameters like delay and timeout. Control theory analysis is performed on the system to test for stability, controllability, observability. Sensitivity analysis is done to find out the sensitivity of the controller to the delay parameter. The first loop implemented gives feedback to the architecture proposed about symptoms of an attack at the node level. A controller needs to be developed to receive information from different controllers and decision about quarantining needs to be made. This research gives the basic information needed for the controller about what is going on at individual nodes of the network. This information can also be used to increase sensitivity of other loops to increase the effectiveness of feedback architecture.

Purpose of this master´s thesis is the construction proposal of azimuth fork mount with load capacity to 20kg including both axes drives. The solution contains design options of azimuth fork mount, calculations, design proposal of the mount and drawings of the shaft, fork and the assembly.

This work contains a proposal for constructions and workings of a worm mixer of clay, lime, cementand fly ash with water for delivery quantity 18 tons per an hour. The introduction describes problems of mixing and mixers in the preparation of building materials. I have mentioned calculation of the main proportions and drive under the relevant norms and self-fortress control of the stresssed parts of mixer. Drawing documentation is worked into the ACad program and contains the configurations of the proposed machinery and detailed subassembly of important parts of worm mixer.

No description available.

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa, in fulfilment of the requirements for the degree of Master of Science. August 2015 / The impacts of mining on the environment continue to pose a risk in many regions. Palabora Mining Company (PMC) situated in Limpopo Province, South Africa is of environmental interest because of its shared border with South Africa’s Kruger National Park. PMC generates both gaseous (emitted from the reverberator (Rev; also known as a smokestack)) and solid (stored in the tailings storage facility (TSF)) waste products. To assess possible pollution to the environment from PMC’s activities, two study species were chosen, the Anomalous Emperor Moth (Imbrasia belina [Westwood 1849] (Lepidoptera: Saturniidae)) and its primary host the mopane tree (Colophospermum mopane [Kirk ex Benth.]). In addition to these two species being abundant on and around PMC, the mopane moth and all stages of its lifecycle are a source of food to many animals, and mopane caterpillars are a valuable source of food and income to many people in this region. Mopane caterpillars and mopane leaves were collected from on and around PMC at varying distances from the reverberator and TSF, as well as from several control sites. The elemental contents of these samples were analysed for 25 elements, focusing on copper, iron, aluminium, silicon, arsenic, zinc, nickel, lead, mercury, chromium and cadmium. In addition to these elemental analyses, the carbon and nitrogen isotopic compositions of these samples as well as caterpillar headwidth, body mass and mandible wear were also measured to assess the impacts of elemental concentrations on caterpillar growth. No mopane caterpillars were found at the two reverberator sites closest to the reverberator itself. Overall these two reverberator sites appear to be most contaminated, as concentrations of 14 of the 25 elements measured were highest in the mopane leaves from these two sites. The copper concentrations at these two sites, 42 ppm and 29 ppm respectively, were at levels that are considered toxic to plants. Assuming that 10 mopane caterpillars (each weighing 5g) are consumed a day, copper concentrations in the mopane caterpillar bodies across sites (between 8 ppm and 12 ppm) would equate to a maximum of 0.56 mg.day-1, which is less than the recommended maximum intake level of 10 mg.day-1 suggested for humans. As there was little difference between sites in terms of leaf carbon and nitrogen composition, elemental concentrations do not appear to be affecting the nutritional content of the leaves. This would suggest that caterpillar growth is not affected by elemental concentrations at sites where they can survive. Similarly, caterpillar headwidths did not vary greatly between sites for each instar, suggesting that elemental concentrations are not affecting mopane caterpillar growth. Headwidths and mandible wear were found to be useful tools to age mopane caterpillars within an instar, and can be used in future to ascertain if mopane caterpillars are bioaccumulating elements or eliminating excess elements when they moult.

No description available.