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Nickel based superalloy are in demand for high temperature applications and their corrosion, erosion and wear resistance have been investigated for a long time. Nickel chromium (NiCr) alloys are widely used for corrosion resistant coatings, while chromium carbide nickel chromium (CrC-NiCr) alloys are preferred for wear resistant coatings at high temperature. In this study CrNiAlCY coatings were deposited via a liquid fuelled high velocity oxy fuel (HVOF) thermal spray using two spray parameters and tested as wear resistant coatings. Effects of processing parameters on microstructure and mechanical properties of the coatings were investigated. Results showed that higher oxygen flow rates are critical for obtaining coatings with lower porosity and higher microhardness. Coating with lower porosity and higher hardness was chosen for both room temperature (~24 °C) and high temperature (900 °C) unlubricated sliding wear tests in a ball on disc setup. The coating was tested against alumina counterbody under 3 different loading conditions (10, 30 and 60 N). The wear rate of the coating was directly proportional to the applied load at room temperature. In the room temperature tests, wear debris was produced, which then oxidised and pushed away to the edges of the wear track. On the other hand, wear debris was smeared on the wear surface at high temperature tests. The surface was oxidised into Cr2O3 at high temperatures, which acted as a protective layer. Although thermal softening took place at higher temperatures, wear rates under 10 and 30 N were similar to room temperature values due to the protective oxide layer formed on the top surface; however, the oxide layer under 60 N could not withstand the load, started to crack and lost its protective ability.

Objective: Bariatric surgery is considered the only therapeutic alternative for morbid obesity and its comorbidities. High risks factors are usually linked with this kind of surgery. In order to reduce it, we consider that losing at least 10% of overweight in Morbid Obese (MO) and a minimum of 20% in Super- Obese patients (SO) before surgery, may reduce the morbidity of the procedure. The aim of our study is to demonstrate the effectiveness and tolerance of a balanced energy formula diet at the preoperative stage, comparing it against a low calorie regular diet. Method: We studied 120 patients divided into two groups of 60 each, group A was treated 20 days prior to bariatric surgery with a balanced energy formula diet, based on 200Kcal every 6 hours for 12 days and group B was treated with a low calorie regular diet with no carbs or fat. The last eight days prior to surgery both groups took only clear liquids. We studied the evolution of weight loss, the BMI, as well as behavior of co-morbidities as systolic blood pressure, diastolic blood pressure, glucose controls and tolerance at the protocol. Results: The study shows that patients undergoing a balanced energy formula diet improved their comorbidities statistically significant in terms of decrease in weight and BMI loss, blood pressure and glucose, compared to the group that was treated before surgery with a low calorie regular diet. Nevertheless both groups improving the weight loss and co-morbidities with better surgical results and facilities. Conclusion: A correct preparation of the Morbid Obese patients prior of surgery can reduce the operative risks improving the results. Our study show that the preoperative treatment with a balanced energy formula diet as were included in our protocol in patients undergoing bariatric surgery improves statistical better their overall conditions, lowers cardiovascular risk and metabolic diseases that the patients with regular diet alone. Objetivos: La cirugía bariátrica es considerada la única alternativa terapéutica para el control de la obesidad mórbida y sus co-morbilidades. Dada la complejidad, gravedad y dificultades de estos pacientes, todo lo que hagamos para disminuir los riesgos peri-operatorios debe ser considerado como muy beneficioso para ellos. De este modo consideramos que una disminución como mínimo del 10% en el exceso de peso en los Obesos Mórbidos (OM) y un 20% en los Super-Obesos (SO), antes de la cirugía, puede mejorar los resultados y disminuir la morbimortalidad del procedimiento. El objetivo de nuestro estudio es demostrar la eficiencia y tolerancia de una dieta-fórmula hiperproteica y normocalórica como preparación preoperatoria, comparándola con una dieta hipocalórica de comida habitual. Métodos: De forma prospectiva y aleatorizada, se estudiaron 120 pacientes divididos en dos grupos de 60 cada uno. Las dietas se administraron 20 días previos a la cirugía. Al primer grupo (A), se le aplicó una dieta-fórmula hiperproteica y normocalórica en bricks, conteniendo 200 kcal cada 6 horas durante los primeros 12 días y al segundo grupo (B), una dieta hiperproteica normal sin carbohidratos o grasas. Los últimos 8 días previos a la cirugía se dieron solamente líquidos claros en ambos grupos. El análisis se efectuó sobre la evolución del peso, del IMC, de la presión arterial y de los niveles de glucemia, así como de la tolerancia al procedimiento. Resultados: El estudio demostró que los pacientes pertenecientes al grupo A, mejoraron de forma estadísticamente significativa tanto en la pérdida de peso y del IMC, como de las co-morbilidades estudiadas, frente a los pacientes que integraron el grupo B. Aunque en todo el conjunto, ambos grupos obtuvieron pérdida de peso preoperatoria y mejoría en sus co-morbilidades. Conclusiones: Una preparación adecuada para los pacientes que vayan a ser sometidos a cirugía bariátrica, puede mejorar los resultados y minimizar los posibles efectos indeseables de la misma. Una dieta-fórmula del tipo de la ensayada en nuestro estudio, alcanza los objetivos de pérdida de peso y reducción o control de las co-morbilidades en mejor proporción que las dietas hipocalóricas habituales, mejorando el riesgo cardiovascular y facilitando todo el proceso quirúrgico.

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The zeolite ZSM-5 is well-known for its unique intersecting channel system. This channel system has a great bearing on the shape-selective properties and the long life-times of ZSM-5. In this study, ZSM-5 was modified in various ways to eliminate the external acidity of the catalyst to further improve these properties, and the success and effects of these modifications were investigated primarily using temperature programmed desorption techniques. The internal surface of ZSM-5, a medium pore zeolite, plays a major role in the shape selective properties of this catalyst, due to the diffusional restrictions imposed by the channel system on bulky molecules. Even though the number of acid sites on the external surface is small compared to the total number of acid sites, these easily accessible and non-shape selective acid sites may provide a high turnover rate for non-shape selective reactions. Furthermore, the main cause of deactivation of ZSM-5 is thought to be the formation of polyaromatic molecules on the external surface, which block access to the channels of the catalyst.