Plastic hypodermic needles are a potential solution to the problem of disease spread through needle reuse. Plastics could be used to potentially reduce needle reuse as they are easier to destroy than steel. A key issue in their acceptance is the force required to penetrate a patient; a smaller force is associated with less pain. The effect that needle parameters have on the penetration force is studied in an effort to better understand how to reduce penetration forces and increase the success of penetrations for plastic needles. These parameters - geometry, tip radius, diameter, material, and lubricant - are studied through penetration, buckling, and coefficient of friction testing. The tests are conducted on steel needles, which serve as a control group, as well as two varieties of plastic needles. The outcome is a quantitative understanding of the effect that the various parameters have on penetration force, which is used to inform plastic needle design.

A semiregular tree is a tree where all non-pendant vertices have the same degree. Among all semiregular trees with fixed order and degree, a graph with minimal (adjacency / Laplacian) spectral radius is a caterpillar. Counter examples show that the result cannot be generalized to the class of trees with a given (non-constant) degree sequence. / Series: Research Report Series / Department of Statistics and Mathematics

The main aim of this diploma thesis is to determine the radius of rotation of selected tractors (Zetor Forterra 140 HSX, Zetor Proxima 120 Power and Zetor 7745 Turbo) on three different types of surfaces using different speeds. The literary part deals briefly with the importance and historical development of tractors, the basic knowledge of traction theory, the problems of forces acting on the rolling wheel, and last but not least the construction of the tractor parts. The practical part is mainly focused on determining the radii of rotation of individual tractors on three specified types of surfaces using the three given speeds. The discussion is mainly focused on comparing the radii of rotation meeting ČSN 30 0552 with the radii given by the tractor manufacturer.

O procedimento de dimensionamento de uma linha lateral de irrigação localizada necessita ser avaliado com precisão, devido às perdas de carga tanto distribuídas na tubulação como nas inserções dos emissores com os tubos. Devido a isso, desenvolveu-se uma metodologia para a determinação da perda de carga localizada mediante a formulação de um modelo matemático a partir do índice de obstrução. Estas perdas localizadas podem ser significativas quando comparadas com as perdas de carga totais, devido ao grande número de emissores instalados ao longo da linha lateral. O experimento foi junto ao Departamento de Engenharia Rural (ESALQ-USP) e ajustado para valores número de Reynolds (R), no intervalo de 7.480 a 32.597 para proporcionar fluxo turbulento e velocidade máxima de 2,0 m s-1. A pesquisa foi conduzida em duas etapas: 1) ajuste do fator f para um seguimento de 0,5 m de tubo,sendo realizada 10 repetições, com o intuito de validação da metodologia empregada comparando-se o ajuste dos dados encontrados com os trabalhos existentes na literatura, 2) determinação da perda de carga (hf) em um seguimento de tubo de 1 m de comprimento com emissor devidamente vedado, portanto, pela diferença entre a hf do tubo mais o emissor e a hf do tubo obtido na primeira etapa, obteve-se a perda de carga localizada do emissor (hfe). Além disso, com a determinação da geometria do emissor, pelo projetor ótico HB 400, formulou-se uma equação que permitiu o cálculo da perda de carga localizada utilizando-se as características geométricas do emissor (comprimento do emissor, índice de obstrução e coeficiente de contração). Pelos resultados obtidos para 4 modelos utilizados, o modelo estimou satisfatoriamente para 2 modelos, e também verificou-se que o modelo apresentou um desempenho classificado como \'ótimo\', portanto, podendo ser empregado para estimativa de perda de carga localizada provocada por emissores integrados não coaxiais com geometria semelhante ao emissor Uniram e Drip Net. / The design of a lateral line of trickle irrigation requires an accurate evaluation of head losses in not only the pipe but the emitters as well. A procedure was developed to determine localized head losses within the emitters by the formulation of a mathematical model accounting for the obstruction caused by the insertion point. These localized losses can be significant when compared with the total head losses within the system, due to the large number of emitters typically installed along the lateral line. An experiment was carried out by altering flow characteristics to create Reynolds Number (R) in the interval from 7480 to 32597 to provide turbulent flow and a maximum velocity of 2.0 m s-1. The geometry of the emitter point was determined by an optical projector and sensor. An equation was formulated that allows the localized head loss calculation using the geometric characteristics of the emitter (emitter length, obstruction index and the contraction coefficient). The obtained results for 4 used models, the model esteemed satisfactorily for 2 models, and was also verified that the model presents an acting classified as \'great\', therefore, could be used to estimate localized head loss provoked by non coaxial emitters inserted in polyethylene pipe with similar geometry as the Uniram and Drip Net emitters.

A fratura da extremidade distal do rádio é o tipo de lesão mais comum encontrada nos departamentos de emergência ortopédica. Requer reabilitação efetiva que pode ser feita com contribuições de tecnologias atuais. Para isto foi construído um sistema mecatrônico móvel e interativo a partir de conhecimentos de especialistas na área da saúde e engenharia. O sistema foi testado em trinta pessoas saudáveis, sendo eles profissionais das áreas citadas e a população mais acometida: homens jovens e mulheres pós-menopausa. Os dados obtidos foram analisados, assim como as pistas sociais apresentadas pelos participantes. Após os testes todos responderam um questionário para avaliar o sistema. Os resultados mostraram que o sistema cumpre grande parte dos requisitos necessários para a reabilitação, mas precisa de melhorias. / Distal radius fracture is the most common type of injury found in emergency of orthopedic department. It requires effective rehabilitation that can be made with contributions of current technologies. For this, a mobile and interactive mechatronic system was built from the expertise of specialists in healthcare and engineering. The system was tested in thirty healthy people, the professionals of these areas and the population most affected: young men and postmenopausal women. The data and the social cues presented by the participants were analyzed. They answered a questionnaire to evaluate the system. The results showed that the system meets many rehabilitation requirements, but improvements are necessary.

As fraturas da extremidade distal do rádio são muito comuns em nosso meio, sendo a mais freqüente do punho. Inúmeras pesquisas já foram realizadas sobre o tema e é conhecida a importância da redução anatômica das fraturas intra-articulares; porém, a causa de insucesso no seu tratamento pode ser a associação de outras lesões, envolvendo partes moles e cartilagem. O objetivo foi realizar uma avaliação artroscópica para analisar a incidência das lesões ligamentares e condrais associadas às fraturas intraarticulares da extremidade distal do rádio, correlacionado-a com classificação AO/ASIF. Trinta pacientes, com idade entre 20 a 50 anos, portadores de fratura fechada dos grupos B e C da classificação AO/ASIF foram selecionados. Todos eles foram submetidos à artroscopia do punho, para abordar as lesões intra-articulares e para redução e osteossíntese da fratura. Observou-se uma alta incidência de lesões intra-articulares, sendo que 76,7% deles apresentavam lesão do complexo da fibrocartilagem triangular, 36,6% do ligamento intrínseco escafo-semilunar, 6,6% do ligamento intrínseco semilunar-piramidal e 33,3% com lesão da cartilagem articular maior que três milímetros. Pacientes portadores de fraturas tipo C da classificação AO/ASIF apresentam uma incidência maior de lesões ligamentares associadas. Não houve relação entre a presença de lesão cartilaginosa e a classificação AO/ASIF das fraturas nesta casuística. / Fractures of the distal end of the radius are very frequent in our country and the most common is that of the wrist. Much research was carried out on the subject and the importance of the anatomical reduction of intra-articular fractures is well known, however the cause of unsuccessful treatment may be the association of other injuries involving soft tissues and cartilage. The purpose here was to perform an arthroscopic evaluation to analyze the incidence of ligament and chondral injuries associated to intra-articular fractures of the distal end of the radius, for correlation with the AO/ASIF classification. Thirty patients ranging from 20 to 50 years of age, bearers of closed fractures of groups B and C of the AO/ASIF classification were selected. They were submitted to wrist arthroscopy to treat the intra-articular injuries for fracture reduction and osteosynthesis. A high incidence of intraarticular injuries was noted, 76.7% of them presenting injury of the triangular fibrocartilage complex, 36.6% of the intrinsic scapholunate ligament, 6.6% of the intrinsic lunotriquetral ligament and 33.3% of an injury of the articular cartilage larger than three millimeters. Patients bearers of a type C fracture in the AO/ASIF classification present with a higher incidence of associated ligament injuries. No relation between presence of cartilage injury and AO/ASIF Classification was found in this casuistry.

Thermal Integrity Profiling (TIP) is a relatively new non-destructive test method for evaluating the post-construction quality of drilled shafts. Therein anomalies in a shaft are indicated by variations in its thermal profile when measured during the curing stages of the concrete. A considerable benefit with this method is in the ability to detect anomalies both inside and outside the reinforcement cage, as well as provide a measure of lateral cage alignment. Similarly remarkable, early developments showed that the shape of a temperature profile (with depth) matched closely with the shape of the shaft, thus allowing for a straightforward interpretation of data. As with any test method, however, the quality of the results depends largely on the level of analysis and the way in which test data is interpreted, which was the focus of this study. This dissertation presents the findings from both field data and computer models to address and improve TIP analysis methods, specifically focusing on: (1) the analysis of non-uniform temperature distributions caused by external boundary conditions, (2) proper selection of temperature-radius relationships, and (3) understanding the effects of time on analysis. Numerical modeling was performed to identify trends in the temperature distributions in drilled shafts during concrete hydration. Specifically, computer generated model data was used to identify the patterns of the non-linear temperature distributions that occur at the ends of a shaft caused by the added heat loss boundary in the longitudinal direction. Similar patterns are observed at locations in a shaft where drastic changes in external boundary conditions exist (e.g. shafts that transition from soil to water or air). Numerical modeling data was also generated to examine the relationship between measured temperatures and shaft size/shape which is a fundamental concept of traditional TIP analysis. A case study involving a shaft from which 24hrs of internal temperature data was investigated and compared to results from a computer generated model made to mimic the field conditions of the shaft. Analysis of field collected and model predicted data was performed to examine the treatment of non-linear temperature distributions at the ends of the shaft and where a mid-shaft change in boundary was encountered. Additionally, the analysis was repeated for data over a wide range of concrete ages to examine the effects of time on the results of analysis. Finally, data from over 200 field tested shafts was collected and analyzed to perform a statistical evaluation of the parameters used for interpretation of the non-linear distributions at the top and bottom of each shaft. This investigation incorporated an iterative algorithm which determined the parameters required to provide a best-fit solution for the top and bottom of each shaft. A collective statistical evaluation of the resulting parameters was then used to better define the proper methods for analyzing end effects. Findings revealed that the effects of non-uniform temperature distributions in drilled shaft thermal profiles can be offset with a curve-fitting algorithm defined by a hyperbolic tangent function that closely matches the observed thermal distribution. Numerical models and statistical evaluations provided a rationale for proper selection of the function defining parameters. Additionally, numerical modeling showed that the true temperature-to-radius relationship in drilled shafts is non-linear, but in most cases a linear approximation is well suited. Finally, analysis of both model and field data showed that concrete age has virtually no effect on the final results of thermal profile analysis, as long as temperature measurements are taken within the dominate stages of concrete hydration.

Network administrators typically employ di erent methods for authenticating and authorizing the access to their networks. A exible and scalable network access method is needed to combat the ever increasing network ubiquity brought on by technological advancements. The IEEE 802.1x Port-Based Network Access is a technology that allows transparent authentication to a network. It uses EAP-methods in order to authenticate against a server. There are a lot of di erent EAP-methods to choose from, and they vary in complexity and security. This report will bring up the di erences between the most commonly used authentication methods regarding the authentication time depending on di erent delay and network load. Results showed that EAP-methods that are less complex take less time to perform authentication than their counterparts. When there is no delay, or a very small delay, this might not matter, but when the delay is higher complex EAP-methods take signi cantly longer time to perform the authentication process. This is very negative considering the nature of transparent authentication, and could lead to users becoming annoyed. A general formula for determining how long time an EAP-authentication process will take is presented.

The convergence of future networks relies on the evolution of technology that enables seamless roaming abilities across non-heterogenous networks for mobile clients. This thesis presents an experimental study of a GPRS-WLAN integration scenario where the objective is to analyze various aspects of the issues related to charging, mobility, roaming and security between GPRS and WLAN networks. The mainly discussed integration scenario in this thesis is loosely coupled systems working on RADIUS platforms, which together with MobileIP and IPSec provides the mobile client with a secure and access-technology independent network access platform. In order to accommodate GPRS client authentication for WLAN operators, there is a prominent need for the incorporation of necessary GPRS functionality into present AAA servers. RADIUS has been studied as the initial target for the implementation of a GPRS interface towards SMS-Cs and HLRs.The authentication of a mobile client is performed against a HLR/AuC in a GPRS network, either over SS7 links or through the incorporation of SIGTRAN protocols over SCTP. SIGTRANsolutions has the ability to join WLAN networks in a SS7 resource sharing model where the SS7 authentication signalling traffic is transported over IP networks to a Signalling Gateway acting as the logical interface against SS7 networks. GPRS-WLAN accounting may be solved through direct roaming agreements between mobile operators and in such a case transport CDR’s over FTP between their billing systems. If roaming agreements does not exist, it may be viable to establish relationships between WLANs and brokers as well as mobile operators and brokers. The brokering model provides a scalable model that allows easier exchange of charging and billing information on an infrastructure based on WLAN and GPRS billing systems. Standardised transmission protocols for accounting information such as GTP’/TAP3 may be utilised in order to provide a generic billing exchange format between billing systems and operators. Furthermore, different network architectures may have different requirements in order to accommodate GPRS clients with WLAN access. A few network architectures has been analysed, and the developed GPRS AAA Interface Daemon (GAID) has been put into context in order to present a generic GPRS-WLAN systems integration solution for WLAN operators. The analysed solutions in this thesis give various possibilities for WLAN operators to setup wireless services for bypassing mobile clients. The implementational work provides a RADIUS platform, which can be enhanced with functionality that enables communication over any interface in the future.

In any networking environment, security, connection time and scalability of the network are the major concerns to keep network safe, faster and stable. Administrators working within the networking environment need to have complete account of manageability, scalability and security of the network, so that the organizational data can be kept confidential and maintain integrity. There are different authentication methods used by network administrators for accessing network in wired and wireless environments. As network usage and attacks on network increases, a secure, scalable and standard network protocol is needed for accessing and to keep data safe in both wired and wireless networks. IEEE 802.1x is an IEEE standard used to provide authentication and authorization to the devices over LAN/WLAN. The framework IEEE 802.1x uses EAP for authentication and authorization with a RADIUS server. In this report, an experimental analysis for different EAP authentication methods in both wired and wireless networks in terms of authentication time and the total processing time is presented. Wireshark is used to capture the network traffic on server and client ends. After analyzing each packet timestamps that are captured using Wireshark, it is seen that EAP-MD5 takes less time in both wired and wireless networks, if the number of users increases, there is not much difference in the network connection time. Concerning with security of the network, EAP-MD5 is vulnerable to many attacks so it is not used by many companies. The alternative methods with their strengths and weaknesses are discussed.