Using Simulation to Analyze the Effectiveness of Chitosan as a Green Kinetic Hydrate Inhibitor

Hydrate formation is a very important aspect in the field of gas flow assurance. Hydrates are ice-like formations that are composed of a cage of host molecules (water) entrapping guest molecules (gas). Some conditions must be met for the hydrates to be formed. These are low temperature, high pressure and the existence of water and gas molecules. The main objective of this study, after explaining about hydrate formation and studying means of inhibition is to produce a hydrate formation inhibitor with optimal concentration and degree of deacetylation, after simulating the function this inhibitor. After careful study and analysis, this inhibitor was chosen to be Chitosan, which is a green kinetic hydrate inhibitor. The reason why hydrate inhibitors are needed in the field of gas production, processing and transportation is the major problems that are caused by the hydrate formation. Formation of hydrates inside the pipeline system can cause serious problems such as pipe blockage and corrosion. Pipeline blockage, or at least reduction of the internal diameter of the pipe as a result of hydrate accumulations, can also cause reduction in the production rates, which cost a significant amount of money. Furthermore, the common inhibitors nowadays are considered to be expensive and harmful to the environment. Therefore, this study aims to introduce a hydrate inhibitor that overcomes the limitations and disadvantages of the existing inhibitors. The method of obtaining the inhibitor examined by this study, which is Chitosan, is from the outer skeleton of the crustaceans animals like shrimps. Then the Chitosan is prepared and tested in different deacetylation degrees and concentrations and simulated using Hydoff Software. The results are then analyzed to present the optimal concentration. But before that, the mixture of the gas that is to be used in the simulation is studied for its phase properties in order to know its normal phase properties so that those properties are to be compared with the gas mixture in contact with the inhibitor. These properties are determined using Hydoff Software

Using Simulation to Analyze the Effectiveness of Chitosan as a Green Kinetic Hydrate Inhibitor

Hydrate formation is a very important aspect in the field of gas flow assurance. Hydrates are ice-like formations that are composed of a cage of host molecules (water) entrapping guest molecules (gas). Some conditions must be met for the hydrates to be formed. These are low temperature, high pressure and the existence of water and gas molecules. The main objective of this study, after explaining about hydrate formation and studying means of inhibition is to produce a hydrate formation inhibitor with optimal concentration and degree of deacetylation, after simulating the function this inhibitor. After careful study and analysis, this inhibitor was chosen to be Chitosan, which is a green kinetic hydrate inhibitor. The reason why hydrate inhibitors are needed in the field of gas production, processing and transportation is the major problems that are caused by the hydrate formation. Formation of hydrates inside the pipeline system can cause serious problems such as pipe blockage and corrosion. Pipeline blockage, or at least reduction of the internal diameter of the pipe as a result of hydrate accumulations, can also cause reduction in the production rates, which cost a significant amount of money. Furthermore, the common inhibitors nowadays are considered to be expensive and harmful to the environment. Therefore, this study aims to introduce a hydrate inhibitor that overcomes the limitations and disadvantages of the existing inhibitors. The method of obtaining the inhibitor examined by this study, which is Chitosan, is from the outer skeleton of the crustaceans animals like shrimps. Then the Chitosan is prepared and tested in different deacetylation degrees and concentrations and simulated using Hydoff Software. The results are then analyzed to present the optimal concentration. But before that, the mixture of the gas that is to be used in the simulation is studied for its phase properties in order to know its normal phase properties so that those properties are to be compared with the gas mixture in contact with the inhibitor. These properties are determined using Hydoff Software

Injury of the Synchondrosis of the Dens. Case Report

Background Data: Injuries of the synchondrosis of the dens are very rare and are commonly unstable injuries. Purpose: To report a case of fracture of the synchondrosis of the dens. Study Design: Case report. Patients and Methods: The parents of a 1.5 years old boy reported pain and limitation of neck movements of their child following a minor fall. Imaging studies revealed displaced fracture of the synchondrosis of the base of the dens. The fracture was not amenable to closed reduction. Reduction of the fracture was only possible through direct transoral reduction. Internal fixation was done using one screw using Bohler technique. Results: Healing of the fracture was evident three months following surgical interference. Conclusion: Transoral digtal pressure of the displaced dens is an effective method in reduction of the injured synchondrosis. Fixation with a single screw was effective until healing of the fractured synchondrosis. (2012ESJ021

The incidence of C5-C6 radiculopathy as a complication of extensive cervical decompression: own results and review of literature

Abstract This retrospective study aims to discuss and compare our results with those previously mentioned in the literature with regard to C5-C6 radiculopathy that occurs after decompression carried out for cervical spondylotic myelopathy. There are few reports in the literature referring to the incidence of the C5-C6 radiculopathy following cervical decompression procedures. Some authors believe that the postoperative cord shift is the most likely cause. From January 1994 to November 2002, 121 patients underwent cervical corpectomies for cervical spondylotic myelopathy. The preoperative and the postoperatively discovered paresis have been assessed according to the criteria of the British Medical Council. The Nurick Scale was used to grade the severity of the myelopathic changes. The follow-up period varied from 4 to 111 months with an average of 50 months. Symptoms of C5 and/or C6 radiculopathy appeared in 10 patients (8.2%) postoperatively. Aggravation of a preoperative C5 and/or C6 radiculopathy was seen in 3 patients, while 7 patients developed a new C5 and/or C6 radiculopathy in the immediate postoperative period. These motor deficits resolved completely in 7 patients within 7 months of surgery, whereas a residual motor weakness remained in the other 3 patients. The postoperative C5 motor deficit is not infrequently associated with partial involvement of the C6 root. The lesions can be either unilateral or bilateral with a statistically average frequency of 8%. The prognosis is generally favorable. Our results did not support the hypothesis that the claimed cord shift phenomenon is a possible aetiology

Análisis de vibraciones en turbinas marinas

[Resumen] Las turbinas eólicas marinas flotantes se están convirtiendo en un recurso muy prometedor para la generación de electricidad. Sin embargo, al estar ubicadas en aguas profundas, las condiciones ambientales de alta mar hacen que estén sometidas a fuertes vientos y a las fuerzas de las olas, lo que produce cargas y vibraciones indeseadas en estas estructuras. Por lo tanto, es muy necesario desarrollar modelos y simular tanto estos sistemas de generación de energía como las condiciones externas que pueden inducir oscilaciones en la estructura de los mismos. Un método para reducir las vibraciones de una turbina flotante es a través del uso de dispositivos de control estructural, típicamente utilizados en estructuras civiles. Con este propósito, este trabajo explora el uso de un método de amortiguación mecánica pasiva, llamado "inerter" y proporciona resultados preliminares que confirman su efectividad para disminuir las oscilaciones.[Abstract] Offshore wind turbines are becoming a very promising resource for generating electricity. However, since they are located in deep waters, the environmental conditions of the high seas cause them to be subjected to strong winds and wave forces, which produces unwanted loads and vibrations in these structures. Therefore, it is very necessary to develop models and simulate both these energy generation systems and the external conditions that can induce oscillations in the structure of the same. One method to reduce the vibrations of a floating turbine is through the use of structural control devices, typically used in civil structures. For this purpose, this work explores the use of a passive mechanical damping method, called "inerter" and provides preliminary results that confirm its effectiveness in reducing oscillations.https://doi.org/10.17979/spudc.978849749756

Identification of Brucella by MALDI-TOF Mass Spectrometry. Fast and Reliable Identification from Agar Plates and Blood Cultures

BACKGROUND: MALDI-TOF mass spectrometry (MS) is a reliable method for bacteria identification. Some databases used for this purpose lack reference profiles for Brucella species, which is still an important pathogen in wide areas around the world. We report the creation of profiles for MALDI-TOF Biotyper 2.0 database (Bruker Daltonics, Germany) and their usefulness for identifying brucellae from culture plates and blood cultures. METHODOLOGY/PRINCIPAL FINDINGS: We created MALDI Biotyper 2.0 profiles for type strains belonging to B. melitensis biotypes 1, 2 and 3; B. abortus biotypes 1, 2, 5 and 9; B. suis, B. canis, B ceti and B. pinnipedialis. Then, 131 clinical isolates grown on plate cultures were used in triplicate to check identification. Identification at genus level was always correct, although in most cases the three replicates reported different identification at species level. Simulated blood cultures were performed with type strains belonging to the main human pathogenic species (B. melitensis, B. abortus, B. suis and B. canis), and studied by MALDI-TOF MS in triplicate. Identification at genus level was always correct. CONCLUSIONS/SIGNIFICANCE: MALDI-TOF MS is reliable for Brucella identification to the genus level from culture plates and directly from blood culture bottles

Context sensitive design of provincial road Galliera SP4.

In the past centuries and before the invention of automobile, roads consisted mainly of unpaved paths connecting only few cities. Later, in the beginning of the twentieth century, the automobile was introduced and a new type of the transportation system was born. Therefore, it was necessary to change the condition of roads to fit with the automobiles. With the spread and the development of the automobiles, roads also have developed and increased all over the world. That caused negative effects on the environment and humans’ life quality. Thus, highways associations and communities had to take some steps to reduce these effects and care about environmental and cultural issues with the traditional commitment to safety and mobility, and that is known as context sensitive design. The aim of this thesis is to use the concepts of context sensitive design to reduce the negative environmental impacts of provincial road Galliera, which connects via Colombo in city of Bologna to provincial road 3 in Argelato city. Some solutions were proposed in this thesis to reduce traffic noise, fragmentation, fauna mortality and to improve the aesthetics of the road

La CFAO (le système Everest®)

MONTPELLIER-BU Médecine UPM (341722108) / SudocMONTPELLIER-BU Odontologie (341722110) / SudocMONTPELLIER-BU Médecine (341722104) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF