Effect of cap rock thickness and permeability on geological storage of CO2: laboratory test and numerical simulation

Geological storage of CO2 is considered widely as an efficient method of mitigation of greenhouse gas emission. CO2 storage mechanism includes structural trapping, residual gas trapping, solubility trapping and mineral trapping. The shale cap rock acts as a seal for the storage when CO2 accumulates at the top of the reservoir. The injected CO2 may migrate through the cap rock under buoyancy force or pressure build-up which depends on the seal capacity of the cap rock. As a result, the effectiveness of containment of injected CO2 in the reservoir is largely dependent on the migration rate of CO2 through the cap rock. This paper investigates the effects of CO2 leakage through cap rock by a combination of experimental studies and numerical simulation. Firstly, experimental measurements on shale core samples collected from Australian cap rocks were conducted to determine properties, such as capillary pressure, pore size distribution and permeability. Based on the measured cap rock properties, the effect of thickness and permeability of cap rocks on CO2 leakage was studied using a commercial compositional simulator. Experimental results show that the permeabilities of the shale samples measured by transient pulse technique range from 60 to 300 nD; a non-Darcy calibration factor which equals the ratio of the measured permeability divided by 1000, is identified for samples with permeability lower than 1000 nD. Numerical simulation results show that the largest leakage of CO2 through the seal (cap cock) is about 7.0% with seal thickness of 3m and vertical permeability of 90 nD; both shale thickness and permeability affect the CO2 leakage significantly; with a given seal permeability, the leakage rate has a power relationship with shale thickness

Pore-GNN: A graph neural network-based framework for predicting flow properties of porous media from micro-CT images

This paper presents a hybrid deep learning framework that combines graph neural networks with convolutional neural networks to predict porous media properties. This approach capitalizes on the capabilities of pre-trained convolutional neural networks to extract n-dimensional feature vectors from processed three dimensional micro computed tomography porous media images obtained from seven different sandstone rock samples. Subsequently, two strategies for embedding the computed feature vectors into graphs were explored: extracting a single feature vector per sample (image) and treating each sample as a node in the training graph, and representing each sample as a graph by extracting a fixed number of feature vectors, which form the nodes of each training graph. Various types of graph convolutional layers were examined to evaluate the capabilities and limitations of spectral and spatial approaches. The dataset was divided into 70/20/10 for training, validation, and testing. The models were trained to predict the absolute permeability of porous media. Notably, the proposed architectures further reduce the selected objective loss function to values below 35 mD, with improvements in the coefficient of determination reaching 9%. Moreover, the generalizability of the networks was evaluated by testing their performance on unseen sandstone and carbonate rock samples that were not encountered during training. Finally, a sensitivity analysis is conducted to investigate the influence of various hyperparameters on the performance of the models. The findings highlight the potential of graph neural networks as promising deep learning-based alternatives for characterizing porous media properties. The proposed architectures efficiently predict the permeability, which is more than 500 times faster than that of numerical solvers.Document Type: Original articleCited as: Alzahrani, M. K., Shapoval, A., Chen, Z., Rahman, S. S. Pore-GNN: A graph neural network-based framework for predicting flow properties of porous media from micro-CT images. Advances in Geo-Energy Research, 2023, 10(1):39-55. https://doi.org/10.46690/ager.2023.10.0

Benign intermuscular lipoma in a bitch

A case of intermuscular lipoma located between the external abdominal oblique and internal abdominal oblique muscles in a fourteen- year -old dog is described. Presenting signs, radiographic findings, surgical treatments and the follow-up treatment are discussed

External beam radiotherapy and intracavitary brachytherapy is an acceptable treatment for locally advanced carcinoma of the uterine cervix

Background: Cervical carcinoma is the second most common neoplasm in women worldwide and is the most frequent cancer among women in Bangladesh. In recent years, High Dose Rate (HDR) brachytherapy in combination with External Beam Radiotherapy (EBRT) has been popular in the management of cancers of uterine cervix.Objectives: To evaluate the effectiveness and acute toxicity of four fractions high dose rate intracavitary brachytherapy following pelvic external beam radiotherapy in the treatment of locally advanced cervical carcinoma. Methods: Bangabandhu Sheikh Mujib Medi­cal University & NICRH chosen as a research place for EBRT and HOR brachytherapy. A typical radiotherapy treatment involves daily inadiation for several weeks. Whole pelvis was treated with total dose of SO Gy in 5 weeks. Patients were treated once a day, 5 days a week with a daily fraction size of 2.0 Gy. EBRT: Pelvic radiotherapy dose is 50 Gy in 25 fractions (2.0 Gy per fraction) over 5 weeks. HDR brachytberapy dose is 7 Gy per fraction, total 4 fractions, each in a week over 4 weeks. Results: Ninety-eight patients were entered in the study. Three patients were excluded due to active non-malignant diseases. One patient had active tuberculosis, two patients had severe skin reactions and two patients withdrew following the first HDR application. The remaining Ninety patients were analyzed. Ninety patients completed the prescribed treatment and were evaluated. Eighty had complete response with relief of symptoms, negative Pap-smear and no clinical signs of persistence disease at 3 months. Ten patients had a positive Pap-smear with clinical signs of persis­tence disease. Patients were evaluated before statting treatment with EBRT and before starting treatment with HDR ICBT. Conclusion: It can be easily concluded that 4 fractions of HDR ICBT, 7 Gy each weekly and pelvic EBRT can effectively and safely control locally advanced carcinoma of the uterine cervix. So that EBRT and HDR ICBT is an acceptable treatment for locally advanced carcinoma of the uterine cervix. Careful attention to normal tissue doses such as the rectum, bladder, and small bowel is important in the treatment of locally advanced cervical cancer

Comparison of HRCT of chest findings in different waves during the COVID-19 pandemic: a retrospective descriptive study in COVID dedicated hospital in Bangladesh

Background: The existing COVID-19 epidemic has affected masses of people universally, leading to significant morbidity and mortality. Radiological imaging methods such as high-resolution computed tomography (HRCT), computed tomography (CT) and chest x-ray have played an essential role in diagnosing and managing COVID-19. Methods: This cross-sectional and observational study was conducted in the department of radiology and imaging, Kurmitola General Hospital, Dhaka, Bangladesh, a COVID dedicated hospital. A total number of 469 patients (N=469) from ≤20 to ≥90 years old were included in the study. Data analysis was performed using Statistical Package for the Social Sciences (SPSS) version 25.0. Results: Based on distribution by age group, the highest number of cases in all three waves were among individuals aged 51-60 (126, 26.9%), followed by those aged 61-70 (97, 20.7%) and 41-50 (90, 19.2%). Among the patients with subtle GGO, the proportion of cases was highest in the first wave, followed by a decrease in the second wave and a further decrease in the third wave. The proportion of patients with SCL was highest in the second (44.9%) wave and decreased in the third (5.9%) wave. For both LUL and LLL, the majority of cases with radiological were observed in the “yes” group in all waves, with significantly higher proportions in the “yes” group compared to the “no” group (p value <0.001). Conclusions: The findings highlighted the significance of incorporating routine radiological examinations and monitoring of radiological features in managing and treating COVID-19 patients. The findings in the study also suggested that the percentage of lung involvement increased from the first to the third wave of COVID-19, which is consistent with the increasing trend of COVID-19 cases during the same period

Performance Evaluation of Centralized Reconfigurable Transmitting Power Scheme in Wireless Network-on-chip

Network-on-chip (NoC) is an on-chip communication network that allows parallel communication among all cores to improve inter-core performance. Wireless NoC (WiNoC) introduces long-range and high bandwidth radio frequency (RF) interconnects that can possibly reduce the multi-hop communication of the planar metal interconnects in conventional NoC platforms. In WiNoC, RF transceivers account for a significant power consumption, particularly its transmitter, out of its total communication energy. This paper evaluates the energy and latency performance of a closed loop power management mechanism which enables transmitting power reconfiguration in WiNoC based on number of erroneous received packets. The scheme achieves significant energy savings with limited performance degradation and insignificant impact on throughput

An external validation of the QCOVID3 risk prediction algorithm for risk of hospitalisation and death from COVID-19: An observational, prospective cohort study of 1.66m vaccinated adults in Wales, UK

INTRODUCTION: At the start of the COVID-19 pandemic there was an urgent need to identify individuals at highest risk of severe outcomes, such as hospitalisation and death following infection. The QCOVID risk prediction algorithms emerged as key tools in facilitating this which were further developed during the second wave of the COVID-19 pandemic to identify groups of people at highest risk of severe COVID-19 related outcomes following one or two doses of vaccine. OBJECTIVES: To externally validate the QCOVID3 algorithm based on primary and secondary care records for Wales, UK. METHODS: We conducted an observational, prospective cohort based on electronic health care records for 1.66m vaccinated adults living in Wales on 8th December 2020, with follow-up until 15th June 2021. Follow-up started from day 14 post vaccination to allow the full effect of the vaccine. RESULTS: The scores produced by the QCOVID3 risk algorithm showed high levels of discrimination for both COVID-19 related deaths and hospital admissions and good calibration (Harrell C statistic: ≥ 0.828). CONCLUSION: This validation of the updated QCOVID3 risk algorithms in the adult vaccinated Welsh population has shown that the algorithms are valid for use in the Welsh population, and applicable on a population independent of the original study, which has not been previously reported. This study provides further evidence that the QCOVID algorithms can help inform public health risk management on the ongoing surveillance and intervention to manage COVID-19 related risks

The global impact of tobacco control policies on smokeless tobacco use: a systematic review

BACKGROUND: Smokeless tobacco, used by more than 300 million people globally, results in substantial morbidity and mortality. For smokeless tobacco control, many countries have adopted policies beyond the WHO Framework Convention on Tobacco Control, which has been instrumental in reducing smoking prevalence. The impact of these policies (within and outside the Framework Convention on Tobacco Control) on smokeless tobacco use remains unclear. We aimed to systematically review policies that are relevant to smokeless tobacco and its context and investigate their impact on smokeless tobacco use. METHODS: In this systematic review, we searched 11 electronic databases and grey literature between Jan 1, 2005, and Sept 20, 2021, in English and key south Asian languages, to summarise smokeless tobacco policies and their impact. Inclusion criteria were all types of studies on smokeless tobacco users that mentioned any smokeless tobacco relevant policies since 2005, except systematic reviews. Policies issued by organisations or private institutions were excluded as well as studies on e-cigarettes and Electronic Nicotine Delivery System except where harm reduction or switching were evaluated as a tobacco cessation strategy. Two reviewers independently screened articles, and data were extracted after standardisation. Quality of studies was appraised using the Effective Public Health Practice Project's Quality Assessment Tool. Outcomes for impact assessment included smokeless tobacco prevalence, uptake, cessation, and health effects. Due to substantial heterogeneity in the descriptions of policies and outcomes, data were descriptively and narratively synthesised. This systematic review was registered in PROSPERO (CRD42020191946). FINDINGS: 14 317 records were identified, of which 252 eligible studies were included as describing smokeless tobacco policies. 57 countries had policies targeting smokeless tobacco, of which 17 had policies outside the Framework Convention on Tobacco Control for smokeless tobacco (eg, spitting bans). 18 studies evaluated the impact, which were of variable quality (six strong, seven moderate, and five weak) and reported mainly on prevalence of smokeless tobacco use. The body of work evaluating policy initiatives based on the Framework Convention on Tobacco Control found that these initiatives were associated with reductions in smokeless tobacco prevalence of between 4·4% and 30·3% for taxation and 22·2% and 70·9% for multifaceted policies. Two studies evaluating the non-Framework policy of sales bans reported significant reductions in smokeless tobacco sale (6·4%) and use (combined sex 17·6%); one study, however, reported an increased trend in smokeless tobacco use in the youth after a total sales ban, likely due to cross-border smuggling. The one study reporting on cessation found a 13·3% increase in quit attempts in individuals exposed (47·5%) to Framework Convention on Tobacco Control policy: education, communication, training, and public awareness, compared with non-exposed (34·2%). INTERPRETATION: Many countries have implemented smokeless tobacco control policies, including those that extend beyond the Framework Convention on Tobacco Control. The available evidence suggests that taxation and multifaceted policy initiatives are associated with meaningful reductions in smokeless tobacco use. FUNDING: UK National Institute for Health Research