This work presents a study on the use of cathodic protection as a measure against corrosion in pipelines.The cathodic protection,compliant with the API 5L standard,is implemented here by applying an impressed current,...This work presents a study on the use of cathodic protection as a measure against corrosion in pipelines.The cathodic protection,compliant with the API 5L standard,is implemented here by applying an impressed current,while carefully considering several essential variables,such as soil characteristics,the type and color of the pipeline material,as well as the placement and size of the anode.Therefore,it is crucial to optimize the location and values of anodic overflows or ground resistances to ensure a uniform distribution of potential across the entire structure.In this method,impressed current protection uses an auxiliary anode and an external direct current source to induce a current through the electrolyte and the pipeline,thus countering the resistance of the steel.This approach is advantageous as it allows for the adjustment of electrical characteristics,particularly current levels,to meet specific needs.The factors essential to the effectiveness of cathodic protection systems,which optimize the distribution of protection potential across the structure,largely depend on the precise management of ground resistances during anodic discharge,particularly the attenuation coefficient(α).These factors were studied,and the results obtained were presented and discussed based on their influence.展开更多
1104 patients with Secondary Dyslipidemia and CKD （Chronic Kidney Disease） （females： 387; males： 717; aged： 70 4- 11 years） were given Diflstat with diet to evaluate efficacy and safety. The study lasted two ye...1104 patients with Secondary Dyslipidemia and CKD （Chronic Kidney Disease） （females： 387; males： 717; aged： 70 4- 11 years） were given Diflstat with diet to evaluate efficacy and safety. The study lasted two years. Patients were assigned to three groups （A, B, C） based upon basal renal function. Group A consisted of 180 patients with GFR （glomerular filtration rate） of 67 4- 16 mL/min/m2. TC （Total-Cholesterol） （-31%）, LDLC （LDL-Cholesterol） （-42%）, TG （triglycerides） （-36.8%） levels, and nonHDLC （non HDLC holesterol） （-41%） and TC/HDLC ratio （-40%） were significantly reduced （P 〈 0.001）. GFR （＋2.5%） increased significantly. No significant changes were observed in HDLC （＋13%）. Group B was of 744 patients, 69% （males： 514）, 31% （females： 230） （median age： 70 ± 13 years）, and moderate stage Ill CKD （GFR： 38 ± 12 mL/min/l.73m2）. After 24 months the change of HDLC （＋3.5%） was not significant, while TC （-27%）, TG （-32%）, LDLC （-33%）, non-HDLC （33.4%）, TC/HDLC （-30%）, and GFR （＋2.1%） were statistically significant （P 〈 0.001）. Group C consisted of 180 patients, 51.6% （males： 93）, 48.3% （females： 87） （median age： 72±11 years）, with severe stage IV CKD （GFR： 19 mL/min/l.73m2）. HDLC （＋13%） was not significant, while TC （-32%）, TG （-38%）, LDLC （-35%）, non-HDLC （-38.5%）, TC/HDLC （-40%）, and GFR （＋2.1%） were statistically significant （P 〈 0.001）. An effective but safe lipid-lowering therapy in patients with CKD, may be crucial to prevent cardiovascular events. The treatment with Dill stat~ combined with diet is to be started as soon as possible in patients with CKD in order of improving lipid and lipoprotein profile, and reducing the progression of renal damage.展开更多
This study examines the mechanical and thermal behavior of ten ceramic formulations(C1 to C10)prepared from two types of specimens:Cylindrical Pure clay Specimens(CPC-SP)and Bone Ash Clay Specimens(BAC-SP).The raw mat...This study examines the mechanical and thermal behavior of ten ceramic formulations(C1 to C10)prepared from two types of specimens:Cylindrical Pure clay Specimens(CPC-SP)and Bone Ash Clay Specimens(BAC-SP).The raw materials,sourced from the Missole II clay formation(Douala,Cameroon),were homogenized at room temperature and compacted into cylindrical molds with 10%water to ensure adequate plasticity and shaping.A total of 100 specimens(five replicates per formulation)were produced under a load of 8.8 N to ensure statistical reliability.Firing experiments,conducted between 750 and 1250˚C,showed that BAC-SP specimens retained 3%residual moisture and exhibited superior mechanical performance,with an average Young’s modulus of 6.6 GPa and a fracture stress of 2.56 MPa,compared with 3.56 GPa and 1.66 MPa for CPC-SP.A weight loss on ignition between 1.8 and 2%was recorded in the range of 1120 to 1144˚C,while Poisson’s ratio remained constant at 0.5 for both materials.The incorporation of bovine bone ash significantly enhances the strength and thermal stability of ceramics,offering promising opportunities for optimizing firing conditions and extending their use in advanced technological applications.展开更多
This paper proposes and investigates an optimal pair investment/pension policy for a pay-as-you-go(PAYG)pension scheme.The social planner can invest in a buffer fund in order to guarantee a minimal pension amount.The ...This paper proposes and investigates an optimal pair investment/pension policy for a pay-as-you-go(PAYG)pension scheme.The social planner can invest in a buffer fund in order to guarantee a minimal pension amount.The model aims at taking into account complex dynamic phenomena such as the demographic risk and its evolution over time,the time and age dependence of agents preferences,and financial risks.The preference criterion of the social planner is modeled by a consistent dynamic utility defined on a stochastic domain,which incorporates the heterogeneity of overlapping generations and its evolution over time.The preference criterion and the optimization problem also incorporate sustainability,adequacy and fairness constraints.The paper designs and solves the social planner's dynamic decision criterion,and computes the optimal investment/pension policy in a general framework.A detailed analysis for the case of dynamic power utilities is provided.展开更多
文摘This work presents a study on the use of cathodic protection as a measure against corrosion in pipelines.The cathodic protection,compliant with the API 5L standard,is implemented here by applying an impressed current,while carefully considering several essential variables,such as soil characteristics,the type and color of the pipeline material,as well as the placement and size of the anode.Therefore,it is crucial to optimize the location and values of anodic overflows or ground resistances to ensure a uniform distribution of potential across the entire structure.In this method,impressed current protection uses an auxiliary anode and an external direct current source to induce a current through the electrolyte and the pipeline,thus countering the resistance of the steel.This approach is advantageous as it allows for the adjustment of electrical characteristics,particularly current levels,to meet specific needs.The factors essential to the effectiveness of cathodic protection systems,which optimize the distribution of protection potential across the structure,largely depend on the precise management of ground resistances during anodic discharge,particularly the attenuation coefficient(α).These factors were studied,and the results obtained were presented and discussed based on their influence.
文摘1104 patients with Secondary Dyslipidemia and CKD （Chronic Kidney Disease） （females： 387; males： 717; aged： 70 4- 11 years） were given Diflstat with diet to evaluate efficacy and safety. The study lasted two years. Patients were assigned to three groups （A, B, C） based upon basal renal function. Group A consisted of 180 patients with GFR （glomerular filtration rate） of 67 4- 16 mL/min/m2. TC （Total-Cholesterol） （-31%）, LDLC （LDL-Cholesterol） （-42%）, TG （triglycerides） （-36.8%） levels, and nonHDLC （non HDLC holesterol） （-41%） and TC/HDLC ratio （-40%） were significantly reduced （P 〈 0.001）. GFR （＋2.5%） increased significantly. No significant changes were observed in HDLC （＋13%）. Group B was of 744 patients, 69% （males： 514）, 31% （females： 230） （median age： 70 ± 13 years）, and moderate stage Ill CKD （GFR： 38 ± 12 mL/min/l.73m2）. After 24 months the change of HDLC （＋3.5%） was not significant, while TC （-27%）, TG （-32%）, LDLC （-33%）, non-HDLC （33.4%）, TC/HDLC （-30%）, and GFR （＋2.1%） were statistically significant （P 〈 0.001）. Group C consisted of 180 patients, 51.6% （males： 93）, 48.3% （females： 87） （median age： 72±11 years）, with severe stage IV CKD （GFR： 19 mL/min/l.73m2）. HDLC （＋13%） was not significant, while TC （-32%）, TG （-38%）, LDLC （-35%）, non-HDLC （-38.5%）, TC/HDLC （-40%）, and GFR （＋2.1%） were statistically significant （P 〈 0.001）. An effective but safe lipid-lowering therapy in patients with CKD, may be crucial to prevent cardiovascular events. The treatment with Dill stat~ combined with diet is to be started as soon as possible in patients with CKD in order of improving lipid and lipoprotein profile, and reducing the progression of renal damage.
文摘This study examines the mechanical and thermal behavior of ten ceramic formulations(C1 to C10)prepared from two types of specimens:Cylindrical Pure clay Specimens(CPC-SP)and Bone Ash Clay Specimens(BAC-SP).The raw materials,sourced from the Missole II clay formation(Douala,Cameroon),were homogenized at room temperature and compacted into cylindrical molds with 10%water to ensure adequate plasticity and shaping.A total of 100 specimens(five replicates per formulation)were produced under a load of 8.8 N to ensure statistical reliability.Firing experiments,conducted between 750 and 1250˚C,showed that BAC-SP specimens retained 3%residual moisture and exhibited superior mechanical performance,with an average Young’s modulus of 6.6 GPa and a fracture stress of 2.56 MPa,compared with 3.56 GPa and 1.66 MPa for CPC-SP.A weight loss on ignition between 1.8 and 2%was recorded in the range of 1120 to 1144˚C,while Poisson’s ratio remained constant at 0.5 for both materials.The incorporation of bovine bone ash significantly enhances the strength and thermal stability of ceramics,offering promising opportunities for optimizing firing conditions and extending their use in advanced technological applications.
基金The authors's research is part of the ANR project DREAMeS(ANR-21-CE46-0002)The research of Sarah Kaakai is Funded by the European Union(ERC,SINGER,101054787)。
文摘This paper proposes and investigates an optimal pair investment/pension policy for a pay-as-you-go(PAYG)pension scheme.The social planner can invest in a buffer fund in order to guarantee a minimal pension amount.The model aims at taking into account complex dynamic phenomena such as the demographic risk and its evolution over time,the time and age dependence of agents preferences,and financial risks.The preference criterion of the social planner is modeled by a consistent dynamic utility defined on a stochastic domain,which incorporates the heterogeneity of overlapping generations and its evolution over time.The preference criterion and the optimization problem also incorporate sustainability,adequacy and fairness constraints.The paper designs and solves the social planner's dynamic decision criterion,and computes the optimal investment/pension policy in a general framework.A detailed analysis for the case of dynamic power utilities is provided.
