Introduction: Maternal death or maternal mortality is “the death of a woman occurring during pregnancy or within 42 days of termination, regardless of duration or location, for any specific cause or aggravated b...Introduction: Maternal death or maternal mortality is “the death of a woman occurring during pregnancy or within 42 days of termination, regardless of duration or location, for any specific cause or aggravated by pregnancy or its management, but neither accidental nor fortuitous. Methods: This was a descriptive and analytical cross-sectional study carried out from January 1<sup>st</sup>, 2021 to April 30<sup>th</sup>, 2022 at the Obstetrics Gynecology Clinic of the Sylvanus Olympio University Hospital Center (SOUHC). Results: we noted 86 cases of maternal deaths after referral/evacuation i.e. a maternal mortality rate hospital of 555 maternal deaths per 100,000 LB. The average age of the patients was 31.1 ± 6.3 years with extremes of 15 and 45 years. In 33.7% of cases our patients were resellers. Multiparas represented 33.7% of the sample, they had performed less than three antenatal consultations. Postpartum hemorrhage was the reference reason in 33.7%. In 74.4% of cases, the patients referred had arrived by taxi. In 87.9% of cases, the patients had died of direct obstetric causes. Immediate postpartum hemorrhage accounted for 44.6% of cases and anemia, 36.4%. There is a statistically significant association between the availability of blood product and the avoidability of maternal death after obstetrical referral and/or evacuation (p value = 0.0188 0.05). Conclusion: Determining responsibility for maternal death is not always easy. There is an urgent need to strengthen the policy of reducing maternal mortality in Togo. This remains possible by developing communication strategies and a solid referral/counter-referral system.展开更多
为了准确测量长计数器到源的距离,需要确定长计数器等效中心的位置。对单能中子源,在等效中心处,长计数器可被视为＂点＂探测器,其探测效率与其工作距离成平方反比关系。如果事先知道长计数器在不同工作距离下的探测效率,则可以利用该...为了准确测量长计数器到源的距离,需要确定长计数器等效中心的位置。对单能中子源,在等效中心处,长计数器可被视为＂点＂探测器,其探测效率与其工作距离成平方反比关系。如果事先知道长计数器在不同工作距离下的探测效率,则可以利用该平方反比关系确定长计数器等效中心的位置。利用加速器中子源,分别在0.144 Me V、0.565 Me V、1.2 Me V、2.5 Me V、5.1 Me V以及14.8 Me V等6个能量点刻度了De Pangher长计数器距靶心不同距离处的探测效率,利用平方反比关系得到长计数器在各能量下的等效中心位置。由实验数据拟合出长计数器等效中心到其前端面距离r0与中子能量En的关系曲线,结果表明在0.144-14.8 Me V范围内,r0与中子能量的自然对数近似呈线性关系。展开更多
Purpose Neutrons detection is of paramount importance in nuclear physics experiments,reactor physics,monitoring and control of nuclear reactors and in radiation protection.Among the neutron detectors used are Proporti...Purpose Neutrons detection is of paramount importance in nuclear physics experiments,reactor physics,monitoring and control of nuclear reactors and in radiation protection.Among the neutron detectors used are Proportional Counters(PC to BF3,boron deposition,3He),Our Detection and Measurements laboratory has embarked on a project to develop,design and build proportional counters with boron deposition mainly for gas filling,several prototypes of which have been produced.Method This work presents the Boron-10 Lined Proportional Counters(PC),developed and produced in the Detection and Measurements Department(DDM19).The PC was designed by adopting,for the electrodes,a stainless steel cathode 0.5 mm thick and a gold-plated tungsten anode with diameter of 25μm.The detectors are filled with an Ar-CH4 mixture(10%)at a pressure of 20 cmHg.The boron deposition is performed by the technique of electrophoresis.Result The results obtained using the DDM19 prototype PC(Detector produced in our Detection and Measurement laboratory,2019),show the advantage of electrophoresis as a better boron deposition technique,and the limitation of the surface mass of 10B to optimal values is around 0.5 at 0.6 mg/cm2.Conclusions The characteristics of the gas amplification in the mixture(Ar-CH4(CH410%)),were measured by different methods and compared with the values of the proportional reference counter LND232.The counting plates for the two reference meters LND232 and our DDM19 prototype from 200 to 300 V have slopes ranging from 6.5 to 10%/100 V,and gas amplification factors from 1436 to 1380,respectively.展开更多
Ocean energy has a potential of providing a large amount of renewable energy around the world. One of the forms of ocean energy, tidal stream power is widely recognized as the continuous, predictable and eco-friendly ...Ocean energy has a potential of providing a large amount of renewable energy around the world. One of the forms of ocean energy, tidal stream power is widely recognized as the continuous, predictable and eco-friendly ocean energy source. Unique tandem propellers that can counter-rotate have been designed to generate electric power effectively from a tidal stream. This type of power unit has several advantages compare to the conventional unit with a single propeller. At the design of the tidal stream power unit, it is important to investigate the structure of the tip vortex tubes shedding to predict the load of the propeller. In this research, we investigated the tip vortex shedding using the CFD method for the conventional single propeller and counter-rotating type tandem propellers and estimated the performance efficiency using RANS (Reynolds Averaged Navier-Stokes) model and we confirmed the limitation of RANS model on the calculation of the tip vortex stretching.展开更多
文摘Introduction: Maternal death or maternal mortality is “the death of a woman occurring during pregnancy or within 42 days of termination, regardless of duration or location, for any specific cause or aggravated by pregnancy or its management, but neither accidental nor fortuitous. Methods: This was a descriptive and analytical cross-sectional study carried out from January 1<sup>st</sup>, 2021 to April 30<sup>th</sup>, 2022 at the Obstetrics Gynecology Clinic of the Sylvanus Olympio University Hospital Center (SOUHC). Results: we noted 86 cases of maternal deaths after referral/evacuation i.e. a maternal mortality rate hospital of 555 maternal deaths per 100,000 LB. The average age of the patients was 31.1 ± 6.3 years with extremes of 15 and 45 years. In 33.7% of cases our patients were resellers. Multiparas represented 33.7% of the sample, they had performed less than three antenatal consultations. Postpartum hemorrhage was the reference reason in 33.7%. In 74.4% of cases, the patients referred had arrived by taxi. In 87.9% of cases, the patients had died of direct obstetric causes. Immediate postpartum hemorrhage accounted for 44.6% of cases and anemia, 36.4%. There is a statistically significant association between the availability of blood product and the avoidability of maternal death after obstetrical referral and/or evacuation (p value = 0.0188 0.05). Conclusion: Determining responsibility for maternal death is not always easy. There is an urgent need to strengthen the policy of reducing maternal mortality in Togo. This remains possible by developing communication strategies and a solid referral/counter-referral system.
文摘为了准确测量长计数器到源的距离,需要确定长计数器等效中心的位置。对单能中子源,在等效中心处,长计数器可被视为＂点＂探测器,其探测效率与其工作距离成平方反比关系。如果事先知道长计数器在不同工作距离下的探测效率,则可以利用该平方反比关系确定长计数器等效中心的位置。利用加速器中子源,分别在0.144 Me V、0.565 Me V、1.2 Me V、2.5 Me V、5.1 Me V以及14.8 Me V等6个能量点刻度了De Pangher长计数器距靶心不同距离处的探测效率,利用平方反比关系得到长计数器在各能量下的等效中心位置。由实验数据拟合出长计数器等效中心到其前端面距离r0与中子能量En的关系曲线,结果表明在0.144-14.8 Me V范围内,r0与中子能量的自然对数近似呈线性关系。
文摘Purpose Neutrons detection is of paramount importance in nuclear physics experiments,reactor physics,monitoring and control of nuclear reactors and in radiation protection.Among the neutron detectors used are Proportional Counters(PC to BF3,boron deposition,3He),Our Detection and Measurements laboratory has embarked on a project to develop,design and build proportional counters with boron deposition mainly for gas filling,several prototypes of which have been produced.Method This work presents the Boron-10 Lined Proportional Counters(PC),developed and produced in the Detection and Measurements Department(DDM19).The PC was designed by adopting,for the electrodes,a stainless steel cathode 0.5 mm thick and a gold-plated tungsten anode with diameter of 25μm.The detectors are filled with an Ar-CH4 mixture(10%)at a pressure of 20 cmHg.The boron deposition is performed by the technique of electrophoresis.Result The results obtained using the DDM19 prototype PC(Detector produced in our Detection and Measurement laboratory,2019),show the advantage of electrophoresis as a better boron deposition technique,and the limitation of the surface mass of 10B to optimal values is around 0.5 at 0.6 mg/cm2.Conclusions The characteristics of the gas amplification in the mixture(Ar-CH4(CH410%)),were measured by different methods and compared with the values of the proportional reference counter LND232.The counting plates for the two reference meters LND232 and our DDM19 prototype from 200 to 300 V have slopes ranging from 6.5 to 10%/100 V,and gas amplification factors from 1436 to 1380,respectively.
文摘Ocean energy has a potential of providing a large amount of renewable energy around the world. One of the forms of ocean energy, tidal stream power is widely recognized as the continuous, predictable and eco-friendly ocean energy source. Unique tandem propellers that can counter-rotate have been designed to generate electric power effectively from a tidal stream. This type of power unit has several advantages compare to the conventional unit with a single propeller. At the design of the tidal stream power unit, it is important to investigate the structure of the tip vortex tubes shedding to predict the load of the propeller. In this research, we investigated the tip vortex shedding using the CFD method for the conventional single propeller and counter-rotating type tandem propellers and estimated the performance efficiency using RANS (Reynolds Averaged Navier-Stokes) model and we confirmed the limitation of RANS model on the calculation of the tip vortex stretching.
