Os problemas freqüentes de patologias ortopédicas e traumáticas da coluna vertebral envolvem a colocação de fixadores internos (parafusos longos, os quais são inseridos nos pedículos posteriores até os corpos vertebrais e conectados por fios nas hastes longitudinais podendo ser fixados em todas as posições pelas porcas). Estes fixadores foram simulados no computador através da construção de modelos geométricos dos mesmos, utilizando o software ANSYS 5.5, que consiste de várias ferramentas para análise do projeto baseado no método dos elementos finitos. Foi também utilizado um software para a modelagem das peças e do conjunto do fixador já existente chamado SOLID EDGE, e logo em seguida o mesmo foi transferido para o software ANSYS 5.5 e simulado. Esta comparação servirá como complemento para possíveis modificações das montagens, dimensões e aplicações, não necessitando de novos ensaios mecânicos na máquina universal de ensaios e sim realizando simulações computadorizadas / The frequent problems of orthopedic and traumatic pathologies of the spinal column that involves the placement of an internal fixator (long screws, which are inserted in the subsequent pedicle until the vertebral and connected by bodies for wires in the longitudinal stems could be fastened in all the positions by the screw). These fixators were simulate in the computer through the construction of geometric models of the same ones, using the software ANSYS 5.5, that consists of several tools for analysis of the project based on the method of the finite elements. It was also used a software for the modelling of the pieces and of the group of the fixador already called existent SOLID EDGE, and then the same was transferred to the software ANSYS 5.5 and simulated. This comparison will serve a complement for possible modifications of the assemblies, dimensions and applications, not needing new mechanical test in the universal machine test but accomplishing computerized simulations

Sabe-se que a aplicação de carga influencia na consolidação óssea; e associada ao exercício podem reduzir o tempo de reparação óssea e a permanência com o fixador, que resultaria em muitas vantagens para a prática clínica. O objetivo deste trabalho foi avaliar a influência do exercício em esteira, na consolidação da osteotomia na tíbia de coelhos, tratadas com fixador externo unilateral. O trabalho foi desenvolvido no laboratório de Bioengenharia da Faculdade de Medicina de Ribeirão Preto da USP, utilizando-se 16 coelhos machos adolescentes da raça Nova Zelândia, que foram submetidos a uma osteotomia transversa no terço médio da tíbia e colocação do fixador externo unilateral para fixá-la. Após o procedimento cirúrgico os animais foram divididos em dois grupos: sedentários com n = 10 e exercitados com n = 10 (submetidos a exercícios diários em esteira, com intensidade moderada, durante 10\'). Foi realizada uma avaliação radiográfica no pós-operatório imediato e a cada 10 dias até a oitava semana, quando os animais foram eutanasiados e suas tíbias retiradas e submetidas ao ensaio mecânico de torção. Na avaliação radiográfica observou-se um percentual maior de tíbias consolidadas, num período inferior a 40 dias no grupo exercitado, enquanto que os valores médios das variáveis mecânicas: torque máximo, deformação angular e energia absorvida até a ruptura, não representaram diferença estatística significativa para p menor e igual a 0,05, apesar de ser observada uma tendência para maiores valores de torque no grupo exercitado. Estes resultados sugerem que o exercício não influencia na velocidade e no padrão de consolidação da fratura neste estudo. / It is known that a load application affects bone healing and in association with exercises, it can reduce bone healing time and fixator permanence time, what would result in several advantages in clinical practice. This article is aimed to evaluate the exercises influence on healing in osteotomised tibiae of rabbits fixed unilateral external fixator. This research was developed in the Bioengineering Laboratory of Medical School of Ribeirão Preto - USP. Sexteen young male New Zealand rabbits were submitted to transverse osteotomy in the middle third of the tibia and fixed with unilateral external fixator. After the surgical procedure, animals were divided into 2 groups: sedentary (n = 10) and exercised (n = 10), being the last group submitted to dayly exercises on a mat for 10 minutes with moderate intensity. A radiographic control was made in the immediate post-operative period and every 10 days during the first 8 weeks. After that, animals were euthanized and their tibia were removed and submitted to a torsional test. For the exercised group, there was observed a larger percentage of healed tibia in a period shorter than 40 days in respect to the radiographic control. The means of mechanical variables (maximum torque, angular displacement and energy required to failure) have shown no significant statisticall difference for p less and equal a 0.05, although it was noticed a tendency to higher values of torque in the exercised group. These results suggest no influence of exercises in relation the speed of and fracture healing in this study.

Clubfoot is one of the most common pathologies of the foot affecting 1 in 1000 newborn babies according to statistics. The first treatment approach is by using conventional procedures, such as plaster and cast, and, the literature reports a range of failures causing relapse. Patients with severe or relapsed cases or patients that are treated later in life may require unconventional procedures to provide correction. In order to increase the success rate after the correction, it is necessary to: a)perform analyses to improve the current treatments and b) investigate the tissues involved in this pathology in order to have a better understanding of clubfoot to develop future treatments. The Ilizarov fixator has been shown to be a good alternative for complex and relapsed cases. However, there are no numerical nor experimental studies to: a) improve the efficiency of the frame deployment for clubfoot, b) provide guidance on the right adjustment procedures, and c) understand the mechanical behaviour of the frame applied to clubfoot. This makes the adjustments fully dependent on the surgeon's experience instead of systematic guidelines/procedures. This results in configurations that induce stresses in the fixator that are transferred to the tissues and leading to a reduction in the success rate. Furthermore, the literature on the correction of clubfoot in babies and the role of the tissues in babies' feet during the correction is limited. Therefore, the aim of the thesis is to analyse the relationship between the adjustments of the connectors and the displacements of the fixator rods, on the one hand, and the stress-strain induced in the rods and fixator, on the other hand. This is achieved by means of a finite element analysis of the stress-strain distributions in the fixator components. The predicted stresses are used for the identification of the components that should be adjusted in the fixator to prevent them from failure. The findings and results in the thesis will enable surgeons to understand better the mechanical behaviour of the Ilizarov frame in clubfoot, and they will facilitate the establishment of a functional range of the fixator in order to improve the current procedures. Another aim is to investigate the mechanical behaviour of one of the most affected bones during the correction of clubfoot in babies, namely the talus. The literature reports a change of shape in the talus during clubfoot correction using conventional procedures. This can result in a change of the stress distribution in the foot tissues during gait in latter stages of life leading to different pathologies. This clearly shows the importance of investigating the mechanical behaviour of the talus. This is the first numerical study to investigate the right adjustment procedures of the frame for clubfoot. It is expected that the findings of this research contribute to the improvement of the current corrective procedures based on the use of the Ilizarov frame and to improve the understanding of clubfoot in babies.

Sabe-se que a aplicação de carga influencia na consolidação óssea; e associada ao exercício podem reduzir o tempo de reparação óssea e a permanência com o fixador, que resultaria em muitas vantagens para a prática clínica. O objetivo deste trabalho foi avaliar a influência do exercício em esteira, na consolidação da osteotomia na tíbia de coelhos, tratadas com fixador externo unilateral. O trabalho foi desenvolvido no laboratório de Bioengenharia da Faculdade de Medicina de Ribeirão Preto da USP, utilizando-se 16 coelhos machos adolescentes da raça Nova Zelândia, que foram submetidos a uma osteotomia transversa no terço médio da tíbia e colocação do fixador externo unilateral para fixá-la. Após o procedimento cirúrgico os animais foram divididos em dois grupos: sedentários com n = 10 e exercitados com n = 10 (submetidos a exercícios diários em esteira, com intensidade moderada, durante 10\'). Foi realizada uma avaliação radiográfica no pós-operatório imediato e a cada 10 dias até a oitava semana, quando os animais foram eutanasiados e suas tíbias retiradas e submetidas ao ensaio mecânico de torção. Na avaliação radiográfica observou-se um percentual maior de tíbias consolidadas, num período inferior a 40 dias no grupo exercitado, enquanto que os valores médios das variáveis mecânicas: torque máximo, deformação angular e energia absorvida até a ruptura, não representaram diferença estatística significativa para p menor e igual a 0,05, apesar de ser observada uma tendência para maiores valores de torque no grupo exercitado. Estes resultados sugerem que o exercício não influencia na velocidade e no padrão de consolidação da fratura neste estudo. / It is known that a load application affects bone healing and in association with exercises, it can reduce bone healing time and fixator permanence time, what would result in several advantages in clinical practice. This article is aimed to evaluate the exercises influence on healing in osteotomised tibiae of rabbits fixed unilateral external fixator. This research was developed in the Bioengineering Laboratory of Medical School of Ribeirão Preto - USP. Sexteen young male New Zealand rabbits were submitted to transverse osteotomy in the middle third of the tibia and fixed with unilateral external fixator. After the surgical procedure, animals were divided into 2 groups: sedentary (n = 10) and exercised (n = 10), being the last group submitted to dayly exercises on a mat for 10 minutes with moderate intensity. A radiographic control was made in the immediate post-operative period and every 10 days during the first 8 weeks. After that, animals were euthanized and their tibia were removed and submitted to a torsional test. For the exercised group, there was observed a larger percentage of healed tibia in a period shorter than 40 days in respect to the radiographic control. The means of mechanical variables (maximum torque, angular displacement and energy required to failure) have shown no significant statisticall difference for p less and equal a 0.05, although it was noticed a tendency to higher values of torque in the exercised group. These results suggest no influence of exercises in relation the speed of and fracture healing in this study.

Os problemas freqüentes de patologias ortopédicas e traumáticas da coluna vertebral envolvem a colocação de fixadores internos (parafusos longos, os quais são inseridos nos pedículos posteriores até os corpos vertebrais e conectados por fios nas hastes longitudinais podendo ser fixados em todas as posições pelas porcas). Estes fixadores foram simulados no computador através da construção de modelos geométricos dos mesmos, utilizando o software ANSYS 5.5, que consiste de várias ferramentas para análise do projeto baseado no método dos elementos finitos. Foi também utilizado um software para a modelagem das peças e do conjunto do fixador já existente chamado SOLID EDGE, e logo em seguida o mesmo foi transferido para o software ANSYS 5.5 e simulado. Esta comparação servirá como complemento para possíveis modificações das montagens, dimensões e aplicações, não necessitando de novos ensaios mecânicos na máquina universal de ensaios e sim realizando simulações computadorizadas / The frequent problems of orthopedic and traumatic pathologies of the spinal column that involves the placement of an internal fixator (long screws, which are inserted in the subsequent pedicle until the vertebral and connected by bodies for wires in the longitudinal stems could be fastened in all the positions by the screw). These fixators were simulate in the computer through the construction of geometric models of the same ones, using the software ANSYS 5.5, that consists of several tools for analysis of the project based on the method of the finite elements. It was also used a software for the modelling of the pieces and of the group of the fixador already called existent SOLID EDGE, and then the same was transferred to the software ANSYS 5.5 and simulated. This comparison will serve a complement for possible modifications of the assemblies, dimensions and applications, not needing new mechanical test in the universal machine test but accomplishing computerized simulations

O tratamento de fraturas umerais distais em aves impõe grande dificuldade, devido a córtices muito finas dos ossos A artrodese com fixador externo da articulação úmero-rádio-ulnar é inviável para aves que se pretende reintroduzir ao meio ambiente. Doze animais foram divididos em dois grupos: cirurgias bilaterais com anquilose de uma asa (asa estática) e manutenção da articulação da outra (asa dinâmica) (grupo 1), e cirurgia unilateral, com manutenção da função da articulação (asa dinâmica), sendo a outra controle (asa intacta) (grupo 2). Foram feitas avaliações clínicas, radiológicas, morfológicas do osso, histomorfométricas (de ambos os grupos) e de capacidade de vôo (grupo 2). A 6 semanas, todos os animais apresentavam fraturas consolidadas, com excessão de dois animais do grupo 1, que somente apresentaram consolidação das asas dinâmicas às 9 semanas e das estáticas às 12 semanas. Todos os animais do grupo 2 apresentaram capacidade de vôo adequada, antes de 13 semanas após a cirurgia. No grupo 1 o úmero da asa dinâmica representava 99,1% do comprimento do da asa estática, e no grupo 2, estes eram 99,5% em relação à asa intacta. A amplitude da asa, no grupo 2, demonstrou que a relação da asa dinâmica/intacta foi de 93%, e no grupo 1 a relação asa dinâmica/estática foi de 105%. O volume do osso intacto foi de aproximadamente 29% da área estudada, enquanto o da asa estática foi de 19% e das asas dinâmicas, de 22%. Houve diferença entre o número de osteoblástos das asas intactas e dinâmicas, porém não houve diferença entre as asas estáticas e intactas e entre as dinâmicas e as estáticas, e também não houve diferença do número de osteoclástos entre nenhum tipo de asa. A razão da superfície óssea pelo volume ósseo indica a quantidade de áreas de reabsorção. Não houve diferença entre as asas estática e dinâmica, porém houve diferença entre estas e os controles. O método proposto de técnica para fixação de fraturas umerais distais, sem a anquilose da articulação úmero-rádio-ulnar, demonstrou ser efetivo em manter o comprimento ósseo, a amplitude da asa e assim, garantindo a capacidade de vôo das aves tratadas, além de demonstrar ser equivalente histológicamente à técnica tradicional e mais estável de anquilose da articulação, para este tipo de fratura, e até mesmo, no período estudado, ser equivalente ao osso são, sendo um método adequado para a reparação de fraturas distais de úmero em aves quando se pretende a reabilitação destes animais. / The treatment of humeral distal fractures in birds is very difficult, because these bones are very brittle. Ankylosis of the humeral-radio-ulnar joint with an external fixator is unviable for birds intended for re-habilitation and reintroduction. Twelve animals were used and they were divided in two groups: bilateral surgeries, with ankylosis of one wing (static wing) and maintenance of the joint function of the other wing (dynamic wing) (group 1), and unilateral surgery, with maintenance of the joint function of the wing (dynamic wing), and the other was used as control group (intact wing) (group 2). Clinical, radiographic, morphologic and histomorphometric evaluations of the wings and bones (of both groups) and of evaluations of flight capacity (in group 2) were made. At 6 weeks, all animals had healed fractures, except two animals in group 1, that only presented consolidation of the dynamic wing at 9 weeks and the static wings at 12 weeks. All animals in group 2 were capable of flying before 13 weeks after surgery. In group 1, the humerus of the dynamic wing was 99.1% the length of that of the static wing, and in group 2, these were 99.5% compared to the intact wing. Wing amplitude, in group 2, showed a dynamic/ intact ratio of 93%, and in group 1 the dynamic/ static wing ratio was 105%. The volume of the intact bone was approximately 29% of the studied area, while in the static wing it was of 19% and in the dynamic wing, 22%. There was a difference in the number of osteoblasts of the intact and dynamic wings, but there was no difference between static and intact, and between dynamic and static wings, and also, there was no difference in the numbers of osteoclasts between any wings. The bone surface/ volume ratio indicates the amount of resorption areas. There was no significant difference between static and dynamic wings, but there was a difference between static and intact wings. The proposed method of distal humeral fracture fixation technique, without ankylosis of the humerus-radius-ulna joint, demonstrated being effective in keeping bone length, wing amplitude e therefore, guaranteeing flight capacity of the birds treated, as well as being histologically equivalent to the tradicional, more stable, joint ankylosis technique, for thise kind of fracture, and even, for the studied period, being equivalent to healthy bone, being an adequate method for fracture repair for this kind of fracture in birds, when one intends rehabilitation of these animals.

Vários implantes cirúrgicos têm sido desenvolvidos para estabilizar fraturas em seres humanos e animais. O fixador esquelético externo circular de Ilizarov é método de fixação amplamente utilizado para tratamento de fraturas complexas, desvios angulares, bem como no alongamento ósseo. O anel destaca-se como componente fundamental desse dispositivo e as cargas de compressão no mesmo plano do anel são devidas principalmente a fios ligados de um lado ao outro do implante. O estudo teve como objetivo comparar a resistência à compressão axial de anéis de Ilizarov e analisar a composição da liga metálica desses anéis. Foram testados dois diâmetros de anéis de três fabricantes nacionais para os ensaios biomecânicos de compressão axial, divididos em dois grupos com quinze corpos de prova. Os testes foram realizados em máquina universal de ensaios Kratos® modelo KE 3.000MP, dotada de célula de carga de 3000N com velocidade de ensaio de 10 milímetros por minuto. Os parâmetros força e deformação foram enviados ao computador IBM®-PC através do sistema de aquisição analógica Lynx® modelo ADS-2000, que permitiu a gravação dos parâmetros para posterior análise. Também avaliou-se a composição elementar dos anéis através do método TTPIXE (partículas induzidas pela emissão de raios X em alvos espessos) em PIXE externo. Os espectros foram acumulados em buffer-multicanal conectado a um micro-computador pessoal tipo IBM-PC®. A redução de espectros de raios-X foi realizada por meio do programa AXIL. Concluiu-se que os anéis para fixador esquelético externo circular são compostos de liga metálica de alumínio e que existe diferença entre os fabricantes nacionais no ensaio mecânico de compressão axial, sendo que o fabricante A é mais rígido que os outros fabricantes para os dois diâmetros (60 e 80 milímetros) de anel e mais resistente que os outros fabricantes para o anel de 80 milímetros. / Various surgical implants have been developed to stabilize fractures in humans and animals. Ilizarov\'s circular external skeletal fixator is a fixation method widely used for the treatment of complex fractures, angular deviation, as well as in bone lengthening. The ring stands out as a fundamental component of the device and compression loads in the same plane of the ring are due mainly to wires connected from one side to another of the implant. The study aimed to compare the resistance to axial compression on Ilizarovs rings and analyze the alloy composition of these rings. Two diameters were tested of three domestic ring manufacturers for biomechanical axial compression, divided into two groups with fifteen specimens each group. The tests were performed in a universal test machine Kratos® model 3.000MP KE, equipped with a 3000N load cell with a test speed of 10 mm per minute. The strength and deformation parameters were sent to the IBM®-PC computer through the Lynx® analog acquisition system model ADS-2000, which allowed the recording of the parameters for further analysis. Also, the rings alloy composition was evaluated using the TTPIXE method (thick-target particle induced X-ray emission) in external PIXE. The spectra were accumulated in a multi-channel buffer connected to an IBM®-PC type personal microcomputer. The reduction of X-ray spectra was performed using the AXIL program. In conclusion the rings was made from aluminum alloy, witch differs in composition among different fabricants, also the rings showed differences performance in mechanical testing of axial compression, and the manufacturer A is more rigid than the other manufacturers for the two diameters (60 and 80 mm) ring and tougher than the other manufacturers to the 80 mm ring.

The Clamp-Rod Internal Fixator (CRIF) is a fracture fixation implant with growing popularity among veterinarian’s for its versatility and ease of use. Although the CRIF is currently in clinical use, relatively few reports exist describing the biomechanical properties and clinical results of this system. The objective of this study was to determine the in vitro biomechanical properties of a 5mm CRIF/rod construct to a 3.5mm Limited Contact-Dynamic Compression Plate (LC-DCP/rod) construct using a canine femoral gap model. Paired canine femora were treated with 40mm mid-diaphyseal ostectomies and randomly assigned to CRIF/rod or LC-DCP/rod. Five pairs of constructs were tested in bending and five pairs were evaluated in torsion. Single ramp to failure tests were conducted to evaluate construct stiffness, yield load, and failure mode. While CRIF/rod and LC-DCP/rod were not significantly different when evaluated in bending, LC-DCP/rod constructs are significantly more rigid than CRIF/rod constructs at higher torsional loads. Below 10degrees of twist, or 4.92Nm torque, the LC-DCP/rod and CRIF/rod were not statistically different in torsion. Catastrophic injuries of the metacarpophalangeal joint resulting in the disruption of the suspensory apparatus are the most common fatal injuries in thoroughbred racehorses. Fetlock arthrodesis is a procedure designed to mitigate suffering from injury as well as degenerative diseases affecting articulation. The objective of this study is to assess the in vitro biomechanical behavior of techniques for fetlock arthrodesis. Twelve forelimb pairs were collected from adult horses euthanized for reasons unrelated to disease of the metacarpophalangeal joint (MCP). A 14-16-hole broad 4.5mm Locking Compression Plate (LCP) was compared to a 14-16 hole broad Dynamic Compression Plate (DCP). Both constructs used a two “figure-eight” 1.25mm stainless steel wire tension band. Fatigue tests and to failure tests were conducted. There were no significant differences in stiffness between groups for fatigue tests. Stiffness increased after the first fatigue cycle for the LCP/wire (80.56+/-52.22%) and DCP/wire (56.58+/-14.85%). Above 3.5mm of axial deformation there was a statistical difference between the stiffness of the LCP/wire (3824.12+/-751.84 N/mm) and the DCP/wire (3009.65+/-718.25 N/mm) (P=0.038). The LCP/wire showed increased stiffness above 3.5mm compression compared to the DCP/wire. Under fatigue testing conditions the constructs are not statistically different.

This thesis is a result of research aimed at analysis of the Taylor Spatial Frames (TSF) in Orthopaedics. The TSF is a ring external fixator, which are used to stabilise a fracture or provide stability during skeletal limb reconstruction procedures. A sound understanding of the mechanics of the fixator is essential, because mechanical stability is a key factor in bone healing. TSF is in fact an adaptation of the hexapod parallel manipulators for dynamisation of the classical ring fixators of Ilizarov type. Therefore, a general solution for Forward kinematics of parallel manipulators was provided and the solution is visualised in real-time. A three-dimensional visualisation tool for TSF, was developed, which offers improvements over the software provided by the manufacturer. Abaqus/CAE programming interfaces were used to develop two separate systems for automatic creation of FEMs of the TSF: one using beam elements and the other using 3D solid elements. The systems were used for a parametric study on axial compression of the TSF. Components of the TSF were also tested and analysed: o TSF rings were studied extensively, which lead to revealing important facts about their role in the TSF. o Fixation bolts in external fixators were studied by FE technique and the results used to relate bolt-load to the bolt-torque applied. o TSF struts were tested in compression and their load-deflection behaviour and the role of universal joints in them were described. TSF and Ilizarov fixators were tested and compared in axial compression. The results highlighted the important role of the pins and wires in deflection of the fixators.

Vários implantes cirúrgicos têm sido desenvolvidos para estabilizar fraturas em seres humanos e animais. O fixador esquelético externo circular de Ilizarov é método de fixação amplamente utilizado para tratamento de fraturas complexas, desvios angulares, bem como no alongamento ósseo. O anel destaca-se como componente fundamental desse dispositivo e as cargas de compressão no mesmo plano do anel são devidas principalmente a fios ligados de um lado ao outro do implante. O estudo teve como objetivo comparar a resistência à compressão axial de anéis de Ilizarov e analisar a composição da liga metálica desses anéis. Foram testados dois diâmetros de anéis de três fabricantes nacionais para os ensaios biomecânicos de compressão axial, divididos em dois grupos com quinze corpos de prova. Os testes foram realizados em máquina universal de ensaios Kratos® modelo KE 3.000MP, dotada de célula de carga de 3000N com velocidade de ensaio de 10 milímetros por minuto. Os parâmetros força e deformação foram enviados ao computador IBM®-PC através do sistema de aquisição analógica Lynx® modelo ADS-2000, que permitiu a gravação dos parâmetros para posterior análise. Também avaliou-se a composição elementar dos anéis através do método TTPIXE (partículas induzidas pela emissão de raios X em alvos espessos) em PIXE externo. Os espectros foram acumulados em buffer-multicanal conectado a um micro-computador pessoal tipo IBM-PC®. A redução de espectros de raios-X foi realizada por meio do programa AXIL. Concluiu-se que os anéis para fixador esquelético externo circular são compostos de liga metálica de alumínio e que existe diferença entre os fabricantes nacionais no ensaio mecânico de compressão axial, sendo que o fabricante A é mais rígido que os outros fabricantes para os dois diâmetros (60 e 80 milímetros) de anel e mais resistente que os outros fabricantes para o anel de 80 milímetros. / Various surgical implants have been developed to stabilize fractures in humans and animals. Ilizarov\'s circular external skeletal fixator is a fixation method widely used for the treatment of complex fractures, angular deviation, as well as in bone lengthening. The ring stands out as a fundamental component of the device and compression loads in the same plane of the ring are due mainly to wires connected from one side to another of the implant. The study aimed to compare the resistance to axial compression on Ilizarovs rings and analyze the alloy composition of these rings. Two diameters were tested of three domestic ring manufacturers for biomechanical axial compression, divided into two groups with fifteen specimens each group. The tests were performed in a universal test machine Kratos® model 3.000MP KE, equipped with a 3000N load cell with a test speed of 10 mm per minute. The strength and deformation parameters were sent to the IBM®-PC computer through the Lynx® analog acquisition system model ADS-2000, which allowed the recording of the parameters for further analysis. Also, the rings alloy composition was evaluated using the TTPIXE method (thick-target particle induced X-ray emission) in external PIXE. The spectra were accumulated in a multi-channel buffer connected to an IBM®-PC type personal microcomputer. The reduction of X-ray spectra was performed using the AXIL program. In conclusion the rings was made from aluminum alloy, witch differs in composition among different fabricants, also the rings showed differences performance in mechanical testing of axial compression, and the manufacturer A is more rigid than the other manufacturers for the two diameters (60 and 80 mm) ring and tougher than the other manufacturers to the 80 mm ring.