Experimental investigations into the transient behaviours of CO2 in a horizontal pipeline during flexible CCS operations

Power plants with CCS facilities should be operated flexibly because of the variability in electricity demand. Load change, start-up and shutdown will occur during flexible CCS operations. It is necessary to investigate the transient behaviours of CO2 flow in the pipeline during these operations for optimized operation of CCS plants. However, very limited experimental data for gas-liquid two-phase CO2 under CCS conditions are available. As a result, experimental observations of the CO2 transient behaviours were conducted on a CO2 gas-liquid two-phase flow rig. Load change, start-up and shutdown of a CO2 flow process were replicated on the rig. Coriolis flowmeters and high-speed imaging equipment were used to observe the mass flow rate, thermophysical properties and flow regimes of the CO2 flow. There are significant discrepancies in the mass flow rate of two-phase CO2 between the test value and the reference value during the load change. During the start-up operation, the flow regime transits from liquid slug flow to gas bubbly flow and the mass flow rate from the Coriolis flowmeter presents two-step changes. In addition, the depressurization and evaporation of liquid CO2 in the pipeline were observed during the shutdown operation

Simultaneous measurement of electrostatic charge and its effect on particle motions by electrostatic sensors array in gas-solid fluidized beds

Repeated particle-particle and particle-wall collisions and frictions lead to the generation and accumulation of electrostatic charges in the gas-solid fluidized beds. Variations of electrostatic signals are a rich source of information on particle motions and charging, which have rarely been explored and interpreted. To gain a more comprehensive understanding of the induced electrostatic signals in the fluidized beds, an array of arc-shaped induced electrostatic sensors were attached to the outer wall of a fluidized bed. Combined with cross-correlation method, induced electrostatic voltage signals and correlation velocity of particles were measured simultaneously. It was found that electrostatic charges accumulation restrained the particle motions while the average correlation velocity of particles increased with the amount of injecting liquid antistatic agent. Based on the analyses of induced electrostatic signals, the particle correlation velocity, and the particles charge-to-mass ratio under different charging levels, a predictive model of the average particles charge-to-mass ratio was established. Compared with the results obtained from Faraday cup, the estimated results showed a relative error no more than 40%. Simultaneous measurement of particle correlation velocity and particles charge-to-mass ratio were complemented by arc-shaped induced electrostatic sensors array combined with cross-correlation method

Comparative safety and efficacy of percutaneous radiofrequency thermocoagulation and percutaneous balloon compression in CT-guided and local anesthesia for recurrent trigeminal neuralgia

BackgroundThere are several ways to treat trigeminal neuralgia (TN); however, TN may recur after treatment. Although microvascular decompression (MVD) is considered an effective treatment for trigeminal neuralgia, patients with recurrence may not be willing to undergo craniotomy.ObjectiveThis study compared the safety and efficacy of percutaneous radiofrequency thermocoagulation and percutaneous balloon compression for treating recurrent trigeminal neuralgia.MethodsThis was a prospective non-randomized controlled study. A total of 52 with recurrent TN were scheduled to undergo surgery in our Hospital from January–June 2021. The patients were classified into percutaneous radiofrequency thermocoagulation (PRT) and percutaneous balloon compression (PBC) groups based on the treatment. All surgeries were performed under computed tomography guidance and local anesthesia. Post-operative complications were also observed. Pain was assessed using the visual analog scale (VAS) and Barrow Neurological Institute (BNI) scale. Efficacy indices were evaluated at 3, 6, 12, and 18 months after surgery.ResultsDuring follow-up, the efficacy rates of the two methods within 18 months were 76.0 and 88.9%, respectively. All patients had hypoesthesia on the affected side, and no severe complications. Notably, 5 patients (20%) in the PRT group with multiple-branch pain, including the first branch of the trigeminal nerve (V1) pain in the PRT group, received radiofrequency therapy for the supraorbital notch (foramen) after puncture of the foramen ovale. However, multiple pain episodes resolved with only one operation in the PBC group.ConclusionCT-guided percutaneous radiofrequency thermocoagulation and percutaneous balloon compression under local anesthesia may be good options for treating recurrent trigeminal neuralgia. Percutaneous balloon compression may be recommended when multiple branches are involved, particularly in cases of V1 neuralgia

The half-degree matters for heat-related health impacts under the 1.5 °C and 2 °C warming scenarios: Evidence from ambulance data in Shenzhen, China

The Paris Agreement has prompted much interest in the societal and health impacts of limiting global warming to 1.5 °C and 2 °C. Previous assessments of differential impacts of two targets indicate that 1.5 °C warming target would substantially reduce the impact on human health compared to 2 °C, but they mainly focused on the magnitude of temperature changes under future climate change scenarios without any consideration of greater frequency of cumulative heat exposures within a day. Here we quantified the health risks of compound daytime and nighttime hot extremes using morbidity data in a megacity of China, and also identified the time-period of heat exposure with higher risks. Then we projected future morbidity burden attributable to compound hot extremes due to the half-degree warming. We estimated that the 2 °C warming scenario by 2100 as opposed to 1.5 °C would increase annual heat-related ambulance dispatches by 31% in Shenzhen city. Substantial additional impacts were associated with occurrence of consecutive hot days and nights, with ambulance dispatches increased by 82%. Our results suggested that compound hot extremes should be considered in assessment of heat-related health impacts, particularly in the context of climate change. Minimizing the warming of climate in a more ambitious target can significantly reduce the health damage

Effects of moisture content on electrostatic sensing based mass flow measurement of pneumatically conveyed particles

Mass flow rate measurement of pneumatically conveyed particles is desirable for the optimal control of many industrial processes. The unpredicted variation of moisture content in particles affects the accuracy of mass flow measurement of particles in enclosed pipelines using electrostatic electrodes. In this study, the characteristics of measured electrostatic signals from particle flow under different flow conditions are analysed to study the effect of moisture content on the mass flow rate measurement. The measurement principle of ring-shaped electrostatic electrodes, the effects of moisture content on electrification of solid particles, and the experimental setup used in the study are presented. Two types of electrostatic electrodes with different axial widths and structure are adopted to measure the electrostatic signals of nonporous glass beads and porous activated carbon powder on the vertical pipeline of a 74 mm bore gas–solid two-phase flow test rig under various moisture content, mass flow rate and conveying velocity conditions. The experimental results indicate that the amplitude and frequency characteristics of the electrostatic signals change with the moisture content. The deviation of mass flow measurement that caused by the variation of moisture content is analysed, and a recalibration process is demonstrated to be effective for the improvement of measurement accuracy

Molecular physiological studies on health effects of dietary nicotinamide riboside, a vitamin B3

Scope: Vitamin B3 serves as a precursor of NAD+, a multifunctional molecule that is involved in various cellular processes, such as energy metabolism, inflammation and insulin signalling. Adequate intake of vitamin B3 is essential to maintain health, especially in aging and obese subjects. In addition, vitamin B3 supplementation in certain high doses have been considered as a therapeutic strategy to counteract the decline of metabolic health that occurs in some diseases, such as type II diabetes. Nicotinamide riboside (NR) is a novel dietary vitamin B3, thus having large potential as dietary component, in fortification or as supplement. However, it is not known how NR as an exclusive source of vitamin B3 affects metabolic health. A better understanding of these effects and the relevant underlying molecular mechanisms will contribute to the proper use of this vitamin B3 in dietary and clinical approaches for health improvement and disease prevention. Objective: The aim of this thesis was to elucidate the effects of dietary NR on whole body metabolic health and to identify the associated molecular and physiological responses. Material and methods: Dietary intervention studies were performed in a C57BL/6JRcc mouse strain, an animal model with an intact nicotinamide nucleotide transhydrogenase (NNT) gene as is present in humans. To exclude the interference of other forms of vitamin B3, we employed a semi-purified rodent diet and used NR as an exclusive source of vitamin B3. To minimize the interaction effects of Trp on NR metabolism, we reduced dietary Trp by a low, but sufficient level. To compromise metabolic health, a mildly obesogenic diet was used. To understand effects on the whole body level, MRI was employed to monitor changes in body composition over time as well as a standardized indirect calorimetry based challenge tests to assess metabolic flexibility and oral glucose tolerance tests (OGTT) to assess glucose tolerance. Both indirect calorimetry and OGTT were used to determine the capacity to respond to perturbation of metabolic homeostasis. To explore molecular mechanisms, we harvested blood and tissue samples and analysed circulating lipids, cholesterols and proteins using enzymatic reaction kits, ELISA kits and multiplex assay; analysed tissue histological changes using immunohistochemistry and immunofluorescence; and analysed molecular changes in tissues using real-time qRT-PCR, transciptomics, western blot as well as metabolomics. At the tissue level, the focus was mainly on morphology and molecular regulation in white adipose tissue (WAT), although transcriptional responses in skeletal muscle and brain were also examined. Main results: 30 mg NR per kg diet was most beneficial for metabolic health, based on metabolic flexibility, WAT morphology and gene expression. High dose of NR (9000 mg NR per kg diet) impaired metabolic flexibility and glucose tolerance, and induced WAT dysfunction including a decreased insulin sensitivity and aggravated inflammation, which may be molecularly explained by a mechanism of SIRT1-mediated PPARγ repression due to an enhanced NAD+/NADP+ pool. Vitamin B3 withdrawal resulted in a mild vitamin B3 deficiency, showing a reduced insulin sensitivity and a downward tendency of metabolic flexibility. The downregulation of Anp32a,Tnk2 and the upregulation of Mapk1, Map2k1, Mthfs, Mthfsl and Qdpr were proposed as a WAT transcriptional signature marker for mild vitamin B3 deficiency. Dietary NR affects motor performance in a dose-dependent pattern, with 30 mg NR per kg diet being best. Vitamin B3 deficient diet (5 mg NR per kg diet) led to the upregulation of Mapk1 and Mthfs in hypothalamus, while high dose of NR (900 mg NR per kg diet) induced the upregulation of hypothalamic Tdo2. The regulation of these genes indicated that tetrahydrofolate (THF) metabolism and Trp metabolism may be affected in the brain by dietary vitamin B3. Conclusions and implications: 30 mg NR per kg diet, or 2.3 mg NR per kg body weight per day, to be optimal for health of male adult mice fed a moderate high-fat diet containing a reduced, but sufficient, Trp level. Both inadequate intake and excessive intake of vitamin B3 can negatively affect metabolic health. In both conditions metabolic flexibility and insulin sensitivity were impaired, but the underlying mechanisms were distinct. We also proposes molecular biomarkers for mild vitamin B3 deficiency. When validated in humans it can be used to establish the prevalence of subclinical vitamin B3 deficiency in humans. Overall, this thesis underlines the importance of an optimal vitamin B3 intake to support health.</p

Molecular physiological studies on health effects of dietary nicotinamide riboside, a vitamin B3

Scope: Vitamin B3 serves as a precursor of NAD+, a multifunctional molecule that is involved in various cellular processes, such as energy metabolism, inflammation and insulin signalling. Adequate intake of vitamin B3 is essential to maintain health, especially in aging and obese subjects. In addition, vitamin B3 supplementation in certain high doses have been considered as a therapeutic strategy to counteract the decline of metabolic health that occurs in some diseases, such as type II diabetes. Nicotinamide riboside (NR) is a novel dietary vitamin B3, thus having large potential as dietary component, in fortification or as supplement. However, it is not known how NR as an exclusive source of vitamin B3 affects metabolic health. A better understanding of these effects and the relevant underlying molecular mechanisms will contribute to the proper use of this vitamin B3 in dietary and clinical approaches for health improvement and disease prevention. Objective: The aim of this thesis was to elucidate the effects of dietary NR on whole body metabolic health and to identify the associated molecular and physiological responses. Material and methods: Dietary intervention studies were performed in a C57BL/6JRcc mouse strain, an animal model with an intact nicotinamide nucleotide transhydrogenase (NNT) gene as is present in humans. To exclude the interference of other forms of vitamin B3, we employed a semi-purified rodent diet and used NR as an exclusive source of vitamin B3. To minimize the interaction effects of Trp on NR metabolism, we reduced dietary Trp by a low, but sufficient level. To compromise metabolic health, a mildly obesogenic diet was used. To understand effects on the whole body level, MRI was employed to monitor changes in body composition over time as well as a standardized indirect calorimetry based challenge tests to assess metabolic flexibility and oral glucose tolerance tests (OGTT) to assess glucose tolerance. Both indirect calorimetry and OGTT were used to determine the capacity to respond to perturbation of metabolic homeostasis. To explore molecular mechanisms, we harvested blood and tissue samples and analysed circulating lipids, cholesterols and proteins using enzymatic reaction kits, ELISA kits and multiplex assay; analysed tissue histological changes using immunohistochemistry and immunofluorescence; and analysed molecular changes in tissues using real-time qRT-PCR, transciptomics, western blot as well as metabolomics. At the tissue level, the focus was mainly on morphology and molecular regulation in white adipose tissue (WAT), although transcriptional responses in skeletal muscle and brain were also examined. Main results: 30 mg NR per kg diet was most beneficial for metabolic health, based on metabolic flexibility, WAT morphology and gene expression. High dose of NR (9000 mg NR per kg diet) impaired metabolic flexibility and glucose tolerance, and induced WAT dysfunction including a decreased insulin sensitivity and aggravated inflammation, which may be molecularly explained by a mechanism of SIRT1-mediated PPARγ repression due to an enhanced NAD+/NADP+ pool. Vitamin B3 withdrawal resulted in a mild vitamin B3 deficiency, showing a reduced insulin sensitivity and a downward tendency of metabolic flexibility. The downregulation of Anp32a,Tnk2 and the upregulation of Mapk1, Map2k1, Mthfs, Mthfsl and Qdpr were proposed as a WAT transcriptional signature marker for mild vitamin B3 deficiency. Dietary NR affects motor performance in a dose-dependent pattern, with 30 mg NR per kg diet being best. Vitamin B3 deficient diet (5 mg NR per kg diet) led to the upregulation of Mapk1 and Mthfs in hypothalamus, while high dose of NR (900 mg NR per kg diet) induced the upregulation of hypothalamic Tdo2. The regulation of these genes indicated that tetrahydrofolate (THF) metabolism and Trp metabolism may be affected in the brain by dietary vitamin B3. Conclusions and implications: 30 mg NR per kg diet, or 2.3 mg NR per kg body weight per day, to be optimal for health of male adult mice fed a moderate high-fat diet containing a reduced, but sufficient, Trp level. Both inadequate intake and excessive intake of vitamin B3 can negatively affect metabolic health. In both conditions metabolic flexibility and insulin sensitivity were impaired, but the underlying mechanisms were distinct. We also proposes molecular biomarkers for mild vitamin B3 deficiency. When validated in humans it can be used to establish the prevalence of subclinical vitamin B3 deficiency in humans. Overall, this thesis underlines the importance of an optimal vitamin B3 intake to support health.</p

Damage Mode and Failure Mechanism of Starch-based Aqueous Polymer Isocyanate Plywood Bonded Structure

Aging means that a polymer material’s performance gradually deteriorates, with the loss of use value due to the comprehensive effect of internal and external factors. In this work, a starch-based aqueous polymer isocyanate (API) adhesive joint structure of crosslinking in bonding interface was investigated. The compression shear strength was recognized as a key evaluation index, and the hygrothermal aging experiment tests were accelerated to study the damage mode and failure mechanism of the glue joint structure. The results showed that the adhesive properties of fracture were ductile fracture, and with an increase of aging time, the damage mode of the bonding was transformed from a cohesion damage mode to a cohesion damage with interface damage mode. In the early stages of the aging tests, the effect of temperature on the compression shear strength was most important; however, with the increase of aging time, the effect of humidity became most important