Experimental Evaluation of the Deadtime Phenomenon for GM Detector: Deadtime Dependence on Operating Voltages

A detailed analysis of Geiger Mueller counter deadtime dependence on operating voltage is presented in the manuscript using four pairs of radiation sources. Based on two-source method, detector deadtime is calculated for a wide range of operating voltages which revealed a peculiar relationship between the operating voltage and the detector deadtime. In the low voltage range, a distinct drop in deadtime was observed where deadtime reached a value as low as a few microseconds (22 µs for 204Tl, 26 µs for 137Cs, 9 µs for 22Na). This sharp drop in the deadtime is possibly due to reduced recombination with increasing voltage. After the lowest point, the deadtime generally increased rapidly to reach a maximum (292 µs for 204Tl, 277 µs for 137Cs, 258 µs for 22Na). This rapid increase in the deadtime is mainly due to the on-set of charge multiplication. After the maximum deadtime values, there was an exponential decrease in the deadtime reaching an asymptotic low where the manufacturer recommended voltage for operation falls. This pattern of deadtime voltage dependence was repeated for all sources tested with the exception of 54Mn. Low count rates leading to a negative deadtime suggested poor statistical nature of the data collected for 54Mn and the data while being presented here is not used for any inference

Simultaneous Experimental Evaluation of Pulse Shape and Deadtime Phenomenon of GM Detector

Analysis of several pulse shape properties generated by a Geiger Mueller (GM) detector and its dependence on applied voltage was performed. The two-source method was utilized to measure deadtime while simultaneously capturing pulse shape parameters on an oscilloscope. A wide range of operating voltages (600-1200 V) beyond the recommended operating voltage of 900 V was investigated using three radioactive sources (204Tl, 137Cs, 22Na). This study investigates the relationship between operating voltage, pulse shape properties, and deadtime of the detector. Based on the data, it is found that deadtime decreases with increasing voltage from 600 to 650 V. At these low voltages (600–650 V), the collection time was long, allowing sufficient time for some recombination to take place. Increasing the voltage in this range decreased the collection time, and hence deadtime decreased. It is also observed that rise and fall time were at their highest at these applied voltages. Increasing the voltage further would result in gas multiplication, where deadtime and pulse width are observed to be increasing. After reaching the maximum point of deadtime (~ 250 µs at ~ 700 V), deadtime started to exponentially decrease until a plateau was reached. In this region, it is observed that detector deadtime and operating voltage show a strong correlation with positive pulse width, rise and fall time, cycle mean, and area. Therefore, this study confirms a correlation between detector deadtime, operating voltage, and pulse shape properties. The results will validate our hypothesis that deadtime phenomena at different operating voltages are phenomenologically different

Numerical Investigation of the Thermo-Hydraulic Performance of Water-Based Nanofluids in a Dimpled Channel Flow using Al₂O₃, CuO, and Hybrid Al₂O₃-CuO as Nanoparticles

In this study, the authors study the impact of spherical dimple surfaces and nanofluid coolants on heat transfer and pressure drop. The main objective of this paper is to evaluate the thermal performance of nanofluids with respect to different Reynolds numbers (Re) and nanoparticle compositions in dimpled channel flow. Water-based nanofluids with Al2O3, CuO, and Al2O3-CuO nanoparticles are considered for this investigation with 1%, 2%, and 4% volume fraction for each nanofluid. The simulations are conducted at low Reynolds numbers varying from 500 to 1250, assuming constant and uniform heat flux. The effective properties of nanofluids are estimated using models proposed in the literature and are combined with the computational fluid dynamics solver ANSYS Fluent for the analysis. The results are discussed in terms of heat transfer coefficient, temperature distributions, pressure drop, Nusselt number, friction factors, and performance criterion for all the cases. For all cases of different nanoparticle compositions, the heat transfer coefficient was seen as 35%-46% higher for the dimpled channel in comparison with the smooth channel. Besides, it was observed that with increasing volume fraction, the values of heat transfer and pressure drop were increased. With a maximum of 25.18% increase in the thermal performance, the 1% Al2O3/water was found to be the best performing nanofluid at Re = 500 in the dimpled channel flow

A Numerical Thermal Analysis of a Battery Pack in an Electric Motorbike Application

Today, electric driven motorbikes (e-motorbikes) are facing multiple safety, functionality and operating challenges, particularly in hot climatic conditions. One of them is the increasing demand for efficient battery cooling to avoid the potential thermal stability concerns due to extreme temperatures and the conventional plastic enclosure of the battery pack. A reliable and efficient thermal design can be formulated by accommodating the battery within an appropriate battery housing supported by a cooling configuration. The proposed design includes a battery pack housing made of high conductive materials, such as copper (Cu) and aluminum (Al), with an adequate liquid cooling system. This study first proposes a potted cooling structure for the e-motorbike battery and numerical studies are carried out for a 72 V, 42 Ah battery pack for different ambient temperatures, casing materials, discharge rates, coolant types, and coolant temperatures. Results reveal that up to 53 °C is achievable with only the Cu battery housing material. Further temperature reduction is possible with the help of a liquid cooling system, and in this case, with the use of coolant temperature of 20◦ C, the battery temperature can be maintained within 28 °C. The analysis also suggests that the proposed cooling system can keep a safe battery temperature up to a 5C rate. The design was also validated for different accelerated driving scenarios. The proposed conceptual design could be exploited in future e-motorbike battery cooling for optimum thermal stability

Neutronic Investigation of Alternative & Composite Burnable Poisons for the Soluble-Boron-Free and Long Life Civil Marine Small Modular Reactor Cores

Concerns about the effects of global warming provide a strong case to consider how best nuclear power could be applied to marine propulsion. Currently, there are persistent efforts worldwide to combat global warming, and that also includes the commercial freight shipping sector. In an effort to decarbonize the marine sector, there are growing interests in replacing the contemporary, traditional propulsion systems with nuclear propulsion systems. The latter system allows freight ships to have longer intervals before refueling; subsequently, lower fuel costs, and minimal carbon emissions. Nonetheless, nuclear propulsion systems have remained largely confined to military vessels. It is highly desirable that a civil marine core not use soluble boron for reactivity control, but it is then a challenge to achieve an adequate shutdown margin throughout the core life while maintaining reactivity control and acceptable power distributions in the core. High-thickness ZrB2 150 μm Integral Fuel Burnable Absorber (IFBA) is an excellent burnable poison (BP) candidate for long life soluble-boron-free core. However, in this study, we want to minimize the use of 150 μm IFBA since B-10 undergoes an (n, α) capture reaction, and the resulting helium raises the pressure within the plenum and in the cladding. Therefore, we have considered several alternative and novel burnable BP design strategies to minimize the use of IFBA for reactivity control in this study: (Case 1) a composite BP: gadolinia (Gd2O3) or erbia (Er2O3) with 150 μm thickness ZrB2 IFBA; (Case 2) Pu-240 or Am-241 mixed homogeneously with the fuel; and (Case 3) another composite BP: Pu-240 or Am-241 with 150 μm thickness ZrB2 IFBA. The results are compared against those for a high-thickness 150 μm 25 IFBA pins design from a previous study. The high-thickness 150 μm 25 IFBA pins design is termed the IFBA-only BP design throughout this study. We arrive at a design using 15% U-235 fuel loaded into 13 x 13 assemblies with Case 3 BPs (IFBA+Pu-240 or IFBA+Am-241) for reactivity control while reducing 20% IFBA use. This design exhibits lower assembly reactivity swing and minimal burnup penalty due to the self-shielding effect. Case 3 provides ~10% more initial (beginning-of-life) reactivity suppression with ~70% less reactivity swing compared to the IFBA-only design for UO2 fuel while achieving almost the same core lifetime. Finally, optimized Case 3 assemblies were loaded in 3D nodal diffusion and reactor model code. The results obtained from the 3D reactor model confirmed that the designed core with the proposed Case 3 BPs can achieve the target lifetime of 15 years while contributing to ~10% higher BOL reactivity suppression, ~70% lower reactivity swings, ~30% lower radial form factor and ~28% lower total peaking factor compared to the IFBA-only core

Emphysematous pyelonephritis

Emphysematous pyelonephritis is an acute necrotizing infection of the renal parenchyma, prompt diagnosis and early treatment is crucial because of the high rate of mortality. We report a case of a 55-year-old female patient with ten-year history of diabetes mellitus presented with pain in right flank, fever and malaise. She was diagnosed as a case of emphyse­matous pyelonephritis, and was successfully treated in our department. The case is presented along with a literature review

Wealth-related inequalities of women’s knowledge of cervical cancer screening and service utilisation in 18 resource-constrained countries: evidence from a pooled decomposition analysis

Introduction: Resource-constrained countries (RCCs) have the highest burden of cervical cancer (CC) in the world. Nonetheless, although CC can be prevented through screening for precancerous lesions, only a small proportion of women utilise screening services in RCCs. The objective of this study was to examine the magnitude of inequalities of women’s knowledge and utilisation of cervical cancer screening (CCS) services in RCCs. Methods: A total of 1,802,413 sample observations from 18 RCC’s latest national-level Demographic and Health Surveys (2008 to 2017–18) were analysed to assess wealth-related inequalities in terms of women’s knowledge and utilisation of CCS services. Regression-based decomposition analyses were applied in order to compute the contribution to the inequality disparities of the explanatory variables for women’s knowledge and utilisation of CCS services. Results: Overall, approximately 37% of women had knowledge regarding CCS services, of which, 25% belonged to the poorest quintile and approximately 49% from the richest. Twenty-nine percent of women utilised CCS services, ranging from 11% in Tajikistan, 15% in Cote d’Ivoire, 17% in Tanzania, 19% in Zimbabwe and 20% in Kenya to 96% in Colombia. Decomposition analyses determined that factors that reduced inequalities in women’s knowledge of CCS services were male-headed households (− 2.24%; 95% CI: − 3.10%, − 1.59%; P < 0.01), currently experiencing amenorrhea (− 1.37%; 95% CI: − 2.37%, − 1.05%; P < 0.05), having no problems accessing medical assistance (− 10.00%; 95% CI: − 12.65%, − 4.89%; P < 0.05), being insured (− 6.94%; 95% CI: − 9.58%, − 4.29%; P < 0.01) and having an urban place of residence (− 9.76%; 95% CI: − 12.59%, − 5.69%; P < 0.01). Similarly, factors that diminished inequality in the utilisation of CCS services were being married (− 8.23%; 95% CI: − 12.46%, − 5.80%; P < 0.01), being unemployed (− 14.16%; 95% CI: − 19.23%, − 8.47%; P < 0.01) and living in urban communities (− 9.76%; 95% CI: − 15.62%, − 5.80%; P < 0.01). Conclusions: Women’s knowledge and utilisation of CCS services in RCCs are unequally distributed. Significant inequalities were identified among socioeconomically deprived women in the majority of countries. There is an urgent need for culturally appropriate community-based awareness and access programs to improve the uptake of CCS services in RCCs

Fertility Levels, Trends and Differentials in Pakistan: Evidence from the Population, Labour Force and Migration Survey 1979-80

The objectives of the present report are two fold: (1) to analyse in some detail the fertility data collected in "Population, Labour Force and Migration" (PLM) Survey of 1979; and (2) to compare its findings, wherever necessary, with those of PFS (particularly for current fertility) and other surveys. The report is organized into eight sections, Section 2 is a brief review of earlier fertility levels and trends. Discussion of the PLM Survey and its methodology finds its place in section 3. In Section 4, we have discussed the current parity (children ever born to women at the time of the survey ) by age, marriage duration and age at marriage, as well as differentials in current parity. Early, marital fertility is discussed in section 5. The next two sections provide brief accounts of current fertility. In order to structure our analysis we have identified the women either through their birth cohorts ( current age ) or their marriage cohorts ( years since first marriage ). Realizing that the two fundamental aspects of a woman's chlld bearing life - the number of children she has had and the tempo of her having had them - cannot be fully separated as the results based on one type of measure do not always correspond to those obtained through another. We have, therefore, presented a brief synthesis of various findings in the concluding section

Fertility Levels, Trends and Differentials in Pakistan: Evidence from the Population, Labour Force and Migration Survey 1979-80

The objectives of the present report are two fold: (1) to analyse in some detail the fertility data collected in "Population, Labour Force and Migration" (PLM) Survey of 1979; and (2) to compare its findings, wherever necessary, with those of PFS (particularly for current fertility) and other surveys. The report is organized into eight sections, Section 2 is a brief review of earlier fertility levels and trends. Discussion of the PLM Survey and its methodology finds its place in section 3. In Section 4, we have discussed the current parity (children ever born to women at the time of the survey ) by age, marriage duration and age at marriage, as well as differentials in current parity. Early, marital fertility is discussed in section 5. The next two sections provide brief accounts of current fertility. In order to structure our analysis we have identified the women either through their birth cohorts ( current age ) or their marriage cohorts ( years since first marriage ). Realizing that the two fundamental aspects of a woman's chlld bearing life - the number of children she has had and the tempo of her having had them - cannot be fully separated as the results based on one type of measure do not always correspond to those obtained through another. We have, therefore, presented a brief synthesis of various findings in the concluding section

Rates of IUCD discontinuation and its associated factors among the clients of a social franchising network in Pakistan

Background: Modern Intrauterine contraceptive device (IUCD) is very safe, highly effective reversible and inexpensive family planning method which offers 5-10 years of protection against pregnancy. The contraceptive use in Pakistan has been merely 30% for over a decade with IUCD being the least used method. Higher discontinuation rates are documented in developing countries; however no such data is available for Pakistan. Marie Stopes Society (MSS) established a social franchise outlets network branded as \u27SURAJ\u27 (Sun) in Pakistan to provide quality family planning services. This study attempts to determine IUCD discontinuation rates and its associated risk factors. Using a semi-structured questionnaire, a cross-sectional study was conducted with 3000 clients who availed IUCD services from Suraj provider 6, 12 and 24 month back,. Data were analyzed in SPSS 17.0; adjusted prevalence ratios were calculated to see associations between discontinuation and its risk factors.Case presentation: We found that 22.7% of the IUCD acceptors experienced some health problem; while the overall discontinuation rate was 18.9% with average time of usage of 7.4 (SD ± 5.8) months before discontinuation. Half of them showed health concerns (49.8%); of which a majority (70.2%) returned to Suraj provider for IUCD removal. Women living in Punjab, residing at a travelling time of 30-60 minutes and no previous use of contraceptive are more likely to discontinue IUCD. However, among total women 81.7% still expressed willingness to avail IUCD services from Suraj provider in future, if needed.Conclusion: The findings suggest a need for training the providers and field workers to prevent early discontinuation of IUCD among the Suraj clients and by addressing the health concerns through proper counseling, continued follow-up and immediate medical aid/referral in case of complications