MODELING OF CEMENT ROTARY KILN UNDER OXY-COMBUSTION WITH A COUPLED MULTI-SOLVER APPROACH

International audienceThe cement rotary kiln is the heart of a cement plant. Unfortunately, it also contributes for a great part in CO2 emissions. Studies and research have reached a plateau in terms of energy efficiency and CO2 emissions reduction for combustion with air. Therefore, oxy-combustion that seems to be a promising solution is going to be modeled. On the other hand, traditional modeling of the entire rotary kiln using a Computational Fluid Dynamics (CFD) approach requires unreasonable calculation time and a very fine meshing. A practical approach is thus proposed. This approach consists on modeling each phenomenon on a dedicated solver with adequate meshing and then coupling the solvers to get the required solution. The Component Interaction Network (CIN) is used to solve 3D conduction and radiation by describing the thermal system as a set of nonoverlapping components and modeling their interactions. CFD is used to solve air flow details and the combustion reaction. A model of a cement rotary kiln under normal operating conditions was created following this method and validated based on literature results. Once the model validated, a study of the kiln under oxy-combustion was lead to predict the behavior of the kiln and the feasibility of such a process

Co-Morbid Factors Related to Surgical Complications in Kidney Transplant Patients

Abstract We have studied retrospectively the demographics and different post transplantation morbidities associated with surgical complications in 200 kidney transplant recipients between May 1997 and January 2008. Patients were divided into 2 groups: Group I including 177 patients without surgical complications and Group II including 23 patients who had surgical complications. Baseline demographics and later co-morbidities were analyzed. The baseline characteristics between the 2 groups did not differ significantly, including donor and recipient age and sex, recipient's body mass index, cause of original renal disease, transplantation date, dialysis duration, recipient's degree of sensitization and pre-transplantation diabetes. However significant difference between the 2 groups included: pre and post-transplant hemoglobin blood level differences (2.6 ± 1.8 mg/dl in Group I versus 4.1 ± 2.0 mg/dl in Group II), number of post-transplant transfusions (0.4 ± 0.8 in Group I versus 2.2 ± 3.7 in Group II), duration of hospital stay (10.9 ± 4.3 days in Group I, versus 17.5 ± 9.2 days in Group II), mean serum creatinine upon discharge (1.47 ± 0.84 mg/dl in Group I versus 2.7 ± 2.87 mg/dl in Group II), death and graft failure at 6 months post-transplant (2 in Group I versus 2 in Group II and 3 in Group I versus 5 in Group II respectively). We conclude that surgical complications were associated with significant short and long term co-morbidities, including duration of hospital stay, serum creatinine upon discharge, and death and graft failures at 6 months post-transplantation

Individualization Of Thermophysiological Models For Thermal Sensation Assessment In Complex Environments – A Preliminary Study

International audienceThermal comfort of drivers and passengers inside cars compartments is a subject bouncing back to the spotlight with the electrification of vehicles. In fact, air conditioning and heating systems can reduce the battery autonomy of electric vehicles by up to 50% under certain conditions. On the other hand, although some researchers attempted to consider the individualization of thermal sensation and comfort models, the most used thermal sensation and comfort models nowadays are still those that consider a standard average person. Many studies showed the limitations of these models in predicting thermal comfort for different populations in complex environments. Therefore, if a personal thermal comfort at minimum vehicle energy consumption is required, a deep consideration should be given to the understanding of the individualization of the thermophysiological model and to identifying key parameters that have the most influence on thermal comfort. In order to evaluate the impact of different parameters on thermal sensation and comfort, a literature review was undertaken followed by a sensitivity analysis of some potentially influential parameters such as the basal metabolic rate, body weight, cardiac output, body fat content and clothing by considering the influence of their variations on thermal neutrality status and thermal sensation and comfort