Average Flow Rate Research Articles

Background phase induced steady-state effects in velocity quantification using phase-contrast MRI.

Flow quantification using phase-contrast (PC) MRI is based on steady-state gradient echo (GRE) sequences and is hampered by spatially varying background phase offsets. The purpose of this work was to investigate the effect of steady-state disruptions during PC-MRI GRE sequences on these background phases. Based on these findings, a specific sequence and timing is suggested, and caution is expressed when using typical correction algorithms. Steady-state responses in stationary tissue were investigated in different prospectively triggered through-plane phase-contrast MRI sequence. Different spoiling methods (gradient spoiling/FISP versus gradient+RF spoiling/FLASH) and interleaving of flow encoding gradients (every TR vs. every ECG cycle) were investigated using simulations, in phantoms and in vivo. Additionally, the effect of relaxation times on the phase offsets was simulated and measured. The impact on image- and phantom-based background phase correction was studied. Good agreement between simulation and phantom measurements were observed. Different sequences lead to different spatiotemporal and tissue dependent background phases. Average flow rates in the popliteal artery were over- and underestimated for ECG-interleaved and TR-interleaved FISP acquisitions compared to FLASH, respectively. Background phase measurements are influenced by steady-state effects leading to potentially false background phase quantification. Current background phase correction methods cannot correct for the disturbance.

Can molecular oscillation technology be used as an alternative to acid injection to prevent the clogging of emitters in drip irrigation systems?

AbstractIn this study, molecular oscillation technology (Merus ring), developed to prevent calcification, biofilm formation and corrosion in piping in industrial water treatment systems, was compared as an alternative to acid injection to prevent the clogging of emitters by chemicals, and fresh and saline water were compared on the basis of system performance parameters (coefficient of variation, distribution uniformity, Christiansen uniformity, emission uniformity) and economic aspects. The results revealed that both acid injection and the Merus ring in saline and fresh water resulted in significantly higher average emitter flow rates than the control treatment. Both the Merus ring and the acid injection achieved higher performance parameters with fresh water than with saline water. Acid injection was found to be more effective in preventing clogging of the emitters than the Merus ring when saline water was used. Compared with fresh water, saline water increases emitter clogging. The economic analysis revealed that the Merus ring was more economical ($204.3 ha−1) than acid injection with both fresh water ($318.2 ha−1) and saline water ($578.6 ha−1). Therefore, the Merus ring could be a reliable and environmentally friendly alternative to acid injection to prevent the clogging of emitters in drip systems when saline water is used.

SALIVA FLOW RATE AND PLAQUE SCORE IN CONVENTIONAL SMOKERS

Background: Smoking had become a common habit in the community. The Lampung Dormitory in Yogyakarta had found that people who had consumed cigarettes for more than 1 year had a moderate level of dental and oral hygiene. Teeth and mouths could be said to be clean if they were free of dirt such as debris, plaque, and calculus. Purpose: This study aimed to analyze the relationship between saliva flow rate and plaque score in conventional smokers in Lampung Dormitory. Methods: A type quantitative research with an observational analytical approach was used, employing a cross-sectional design. The population of this study was conventional cigarette users aged 18–30. The number of samples in this study was 70 respondents with sampling using the purposive sampling technique. The research variables were saliva flow rate and plaque score. Saliva was taken by the spitting method, and the plaque scores were measured using the PHP (Personal Hygiene Performance) index. Data analysis used bivariate analysis in the form of a chi-square test. Results: Smokers had a low criterion saliva flow rate (50.0%), and smokers had a poor criterion plaque score (45.7%). The average saliva flow rate was low (0.29±0.08), and the plaque score was poor (2.85±0.81). based on the chi-square test showed that p-value was 0.000. Conclusion: There was a significant relationship between saliva flow rate and plaque score in conventional smokers.

Development of a new high performance liquid chromatography-fluorescence detection (HPLC-FL) method for the determination of biogenic amines in frozen fish sold in markets

<p class="MsoNormal" style="text-align:justify;line-height:200%"><span lang="EN-GB" style="font-size:12.0pt;line-height:200%;font-family:"Times New Roman","serif"; mso-fareast-font-family:"Times New Roman";mso-ansi-language:EN-GB;mso-fareast-language: ZH-CN">It is now possible to measure the biogenic amines histamine, tryptamine, putrescine, cadaverine, spermidine, spermine, and tyramine in an easy, accurate, and selective manner. Dansyl chloride was used to purify the analytes, and high-performance liquid chromatography with detection of fluorescence was utilized for separating them. This is a useful method for identifying and measuring biogenic amines in fish samples in a selective manner. The C18 (250 mm × 4.6 mm × 5 μm) column was used for the separation by chromatography. A mobile phase comprising acetonitrile and phosphate buffer (pH=4.0) (60:40, v/v) was used at an average flow rate of 0.9 mL/min. The technique relied on utilizing fluorescence detection to determine the derivative </span><span style="font-size:12.0pt;line-height:200%;font-family: "Times New Roman","serif"">(λ<sub>ex</sub>=230 nm, λ<sub>em</sub>= 350 nm) </span><span lang="EN-GB" style="font-size:12.0pt;line-height:200%;font-family:"Times New Roman","serif"; mso-fareast-font-family:"Times New Roman";mso-ansi-language:EN-GB;mso-fareast-language: ZH-CN">The suggested method's linearity was examined between 0.01 and 50 μg/mL </span><span style="font-size:12.0pt;line-height:200%;font-family:"Times New Roman","serif"">(r<sup>2</sup>=0.9996). </span><span lang="EN-GB" style="font-size:12.0pt;line-height:200%;font-family: "Times New Roman","serif";mso-fareast-font-family:"Times New Roman";mso-ansi-language: EN-GB;mso-fareast-language:ZH-CN">In compliance with ICH criteria, the method was verified with respect to accuracy, precision, repeatability, specifity, robustness, and detection and quantification limitations. The suggested technique has been effective in tracking the production of biogenic amines in specimens of fish that can be purchased frozen in marketplaces. It was discovered that the recommended approach worked well for routinely analyzing fish sample biogenic amine analyses.<o:p></o:p></span></p>

Comparison of the Role of Anticholinergics and α-1 Adrenergic Blockers in Bladder Management in Posterior Urethral Valves: A Pilot Randomized Control Trial

Introduction: Posterior urethral valve (PUV) is a major cause of congenital bladder dysfunction, often persisting despite treatment. Emerging therapies, including anticholinergics and α-1 blockers, offer potential but lack clear guidelines. This study evaluates their effectiveness in improving bladder function after valve fulguration. Methods: Twenty PUV patients, aged ≥3 years, were randomized into anticholinergic (group A, n = 11) and α-1 adrenergic blocker (group B, n = 9) groups post-fulguration. Follow-up included clinical, radiological, and urodynamic assessments 6 months posttreatment initiation. Results: In group A, the mean maximum detrusor pressure (Pdet) decreased from 30.17 to 23.45 cm H2O (p = 0.033). Two patients normalized from high detrusor pressure (>40 cm H2O). In group B, 1 patient retained high detrusor pressure posttreatment. Group B improved in average urinary flow (Q avg) and maximum flow rate (Q max), with all patients having initially low Q avg (<10 mL/s). Two group B patients showed improved average flow rates posttreatment (p = 0.016); three in group A showed improvement but were not statistically significant (p = 0.197). Q max/flow time ratio was abnormal in all group B patients pretreatment. Two of the nine improved posttreatment, while only one in group A did. Conclusions: Anticholinergic medications positively impact cystometric parameters and are effective for detrusor instability and low compliance bladder. α-Adrenergic blockers influence uroflow parameters and can help treat bladder outflow obstruction. Consideration for a larger study with extended follow-up is warranted.

Numerical simulation of miniature high-speed aviation fuel pump using immersed solid method

Abstract Aviation fuel pumps are developing toward lightweight design and high rotational speeds at the same time that vehicles, such as missiles and unmanned aerial vehicles (UAVs), gradually get smaller. To investigate the internal flow field characteristics of a miniature aviation gear pump under conditions of high rotational speed, three-dimensional numerical simulations are conducted using computational fluid dynamics (CFD) software ANSYS CFX. The simulations use the immersed-solid method and employ the SST k-ω turbulence model. The findings reveal that under identical conditions, augmenting the tooth width by 1mm leads to a notable 27.32% increase in the average outlet flow rate and a corresponding enhancement of 7.22% in maximum efficiency. Furthermore, a 2mm increment in tooth width results in a substantial surge of 62.74% in the average outlet flow rate and a significant enhancement of 14.61% in maximum efficiency. Nevertheless, concurrently, the augmentation of tooth width corresponds with a gradual rise in trapped oil pressure and significant deterioration of the internal flow field. The study findings offer valuable insights into the integrated design of the oil supply system and engine components of aerospace engines.

Analysis of the inhibition effects of C6F12O and low-pressure carbon dioxide on 72 Ah LiFePO4 module under the overcharging abuse condition

Fire disasters that happened in the energy storage station of LiFePO4 (LFP) cells have been growing rapidly in recent years. To meet the urgent need for fire and explosion prevention caused by the abused LFP cells, the application of C6F12O and low-pressure carbon dioxide (LCD) is proposed. The inhibition effects are investigated quasi-quantitatively. While the average mass flow rate of LCD is 4 times higher than that of C6F12O, the economy of LCD far exceeds C6F12O (the quality unit price of C6F12O is about 10 times to LCD). In particular, the suppression time of LCD is 9 times shorter than C6F12O when they were all released at the side of the module box alone. LCD shows extraordinary module cooling ability on the overcharged LFP module. The pure C6F12O application makes it hard to prevent thermal runaway over long durations. The releasing position of C6F12O (directly above the safety valve and on the side of the LFP module) is also tested. It is easier to suppress the flame when C6F12O is released directly above the safety valve. Additionally, the re-ignition is observed due to the electrostatic spark generated by the charging wire during the suppression process.

Increased pulsation ratio in rear quarters reduces machine-on time and milking on empty teats

Dairy cows usually store more milk in rear than in front quarters. At conventional machine milking this leads to an earlier cessation of milk flow in front than in rear quarters and hence unavoidable milking on empty front teats. We tested the hypothesis that an increased pulsation ratio in rear quarters reduces both milking on empty front teats and machine-on time. We have also tested if the different amplitude of cyclic vacuum fluctuations during milking with simultaneous vs. alternate pulsation within front and rear quarters, respectively, impacts milking characteristics. Ten Holstein dairy cows were milked twice daily at 14-h and 10-h milking intervals. Pulsation ratio in front quarters was 65:35, but was either set at 65:35, 70:30, 75:25 or 80:20 in rear quarters. Whole udder milk flow, claw vacuum, and mouthpiece chamber vacuum of all 4 quarters were recorded during milking. Teat tissue thickness of all 4 teats was measured with a cutimeter at 5 and 30 min after cluster detachment. Total milk yield did not differ among treatments, indicating complete udder emptying. The time of quarter milk flow (tQMF) of front quarters did not differ among treatments but decreased with increasing pulsation ratio in rear quarters. In addition, the faster milking of rear quarters at higher pulsation ratio caused higher peak and average milk flow rates, a shorter duration of milk flow decline, and a reduced machine-on time. The increased milk flow at a higher pulsation ratio did not cause a significant reduction of the claw vacuum at the used sample size. Teat tissue thickness did not significantly differ among treatments, likely because milking on empty teats did almost not occur in the rear quarters, and treatment settings did not differ in front quarters. Simultaneous pulsation caused higher amplitudes of cyclic vacuum fluctuation than alternate pulsation. However, milking characteristics did not differ between simultaneous and alternate pulsation. In conclusion, an increased pulsation ratio in rear quarters reduces machine-on time, increases milking performance, and reduces the time of milking on empty teats in front quarters, without an increased impact on teat tissue thickness.

A novel pulse liquid immersion cooling strategy for Lithium-ion battery pack

Ensuring the lithium-ion batteries’ safety and performance poses a major challenge for electric vehicles. To address this challenge, a liquid immersion battery thermal management system utilizing a novel multi-inlet collaborative pulse control strategy is developed. Moreover, different cooling methods (cooling structures, immersion coolants and pulse control method) are numerically investigated to assess their impact. Compared with other structural schemes, the battery module using baffles with fish-like perforations for the 5-in and 5-out scheme demonstrates superior cooling capability while reducing external power consumption. Furthermore, the utilization of FC-3283 exhibits better comprehensive performance compared to AC-100 and mineral oil. Notably, in terms of pulse cooling, when the output ratio reaches 50 %, the battery pack temperature can not only be maintained within a reasonable range, but also the time-averaged pump power consumption decreases by 87.6 % compared to the bottom inlet and top outlet scheme. At the same average flow rate, the liquid immersion battery thermal management system with output ratio of 25 % is the optimal choice for the trade-off between cooling performance and flow resistance, and compared with the bottom inlet and top outlet scheme, the maximum temperature and maximum temperature difference decrease by 23.7 % and 13.9 %, respectively.

Association between automatic milking system parameters and intramammary infections in dairy cows at dry-off

IntroductionThe current global concern over increasing antimicrobial resistance among animal and human pathogens has motivated efforts to reduce antimicrobial drug use in food animals and its impact on antimicrobial resistance. One such strategy is to use selective dry cow therapy (SDCT) in dairy cows, which involves treating only cows with intramammary infection (IMI) at dry-off. However, efficient methods are needed to identify cows with IMI at dry-off to implement SDCT. Automatic Milking Systems (AMS) data may help farmers identify cows with IMI when individual Somatic Cell Count (SCC) is not routinely tested. This study assessed the correlation between cow-level and quarter-level AMS parameters and IMI at dry-off.Methods &amp;amp; ResultsA total of 733 udder quarters (comprising both Primiparous [PRIM] and Multiparous [MULT] cows) were sampled and categorized for IMI based on bacterial growth and SCC. Data were aggregated both daily and into 7-day and 15-day intervals preceding dry-off. The quarter-level prevalence of bacterial growth at dry-off was 24.28% overall. When stratified by parity, logistic regression analysis at 15 days to dry-off revealed that the average difference in mastitis detection index (MDi) in PRIM, MDi, and standard deviation milk flow rate in MULT were associated with increased odds of IMI at dry-off. Similarly, data from 7 days to dry-off revealed that average peak milk flow rate in PRIM, and MDi in MULT were associated with increased odds of IMI at dry-off. However, an increase in average milk yield was associated with decreased odds of IMI.Discussion &amp;amp; ConclusionOur findings underscore the significance of MDi, milk flow rate, peak milk flow rate, and milk yield in predicting IMI at dry-off. Notably, stronger associations were observed with data collected 7 days preceding dry-off. Further research is warranted to refine and validate algorithms amalgamating these variables for precise IMI prediction in cows at dry-off.

Effect of Different Sizes and Heights on the Removal Efficiency of Composite Clay Filter for Gold Mine Site Wastewater Remediation

Wastewater from mining-related activities contains toxic elements that require remediation, and most available wastewater filters have inconsistent flow rates and removal efficiency due to their thickness. This study, therefore, examined the effect of height and size on the flow rate and removal efficiency of a clay composite filter for wastewater remediation. The developed clay filter and its composites were characterized using various techniques such as X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). The XRF analysis showed that the clay contained 91.38% major minerals, including iron oxide (Fe2O3), aluminum oxide (Al2O3), and silica (SiO2), which could enhance the filtration process. Additionally, FTIR revealed that both the clay and the filter are rich in functional groups, including kaolinite and illite, which could promote the filtration process. Further analysis showed that the filters had an average adsorption rate of 87.32%, an average flow rate of 0.891 L/hr, and an average removal efficiency of 99.6%. An increase in the height of a small-diameter filter resulted in a 0.21% increase in removal efficiency, while for larger diameters, the removal efficiency decreased by 0.11%. Conversely, increasing the diameter of a short filter increased the efficiency by 0.25%, while for taller filters, the removal efficiency decreased by 0.07%. Therefore, this work demonstrated that both height and diameter have noticeable effects on flow rate: as height increases, flow rate decreases, and as diameter increases, flow rate increases. The filter's efficiency is somewhat affected by both height and diameter, with a small increase in efficiency noted at greater heights and a slight decrease in efficiency noted at larger diameters.

Control of a Circular Jet with a Disk-Type Bluff Body Using a Dielectric Barrier Discharge Plasma Actuator

In this study, a disk-type bluff body was installed at the upper part of a nozzle exit, and the circular jet inside the nozzle was controlled using a dielectric barrier discharge (DBD) plasma actuator (DBD-PA). The effects of the changes in the excitation frequency of the jet induced by the DBD-PA on the jet diffusion were elucidated. The experiments included visualization of the jet cross-section, particle image velocimetry analysis, and velocity measurements using an I-type hot-wire anemometer. When the DBD-PA was driven at a specific burst frequency (900–1400 Hz), a lock-in phenomenon occurred, in which the frequency of vortices generated in the initial jet coincided with the burst frequency. This lock-in phenomenon suppressed the merging of vortices by generating vortices at regular intervals. When vortex merging was suppressed, the jet was less likely to be entrained into the recirculation flow generated by the bluff body, thereby increasing the downstream jet width and average flow rate.

Uroflowmetry: nomograms in healthy young Pakistani men.

To create a nomogram based on urine volume and flow of males without lower urinary tract symptoms. The prospective, cross-sectional study was conducted at the Department of Urological Surgery and Transplantation, Jinnah Postgraduate Medical Centre, Karachi, from November 1, 2020, to October 31, 2022, and comprised healthy young males without lower urinary tract dysfunction who were recruited from the hospital as well as a large textile mill. They were asked to void on their normal desire. Uroflowmetry was done to determine maximum flow rate, average flow rate, and void volume values. A best-fit regression model was used to formulate uroflowmetry nomogram using average and maximum urine flow rate over voided volume. The sample size was calculated using PASS 2020 Power Analysis and Sample Size Software (2020). NCSS, LLC. Kaysville, Utah, USA. The database was developed on NCSS 2020 Statistical Software (2020). NCSS, LLC. Kaysville, Utah, USA for the data analysis. Of the 468 male subjects enrolled, data was analysed related to 432(92.3%). The mean age was 25.59±4.32 years. Mean maximum flow rate, average flow rate and void volume were 25.28±8.70mL/s, 14.77±4.79mL/s and 405.48±163.86mL, respectively. The association of age was noted with maximum flow rate (r=0.1435, p=0.004), average flow rate (r=0.1135, p=0.004) and void volume (r=0.0619, p=0.004). The best-fitted model for maximum and average flow rate was subsequently developed which was statistically significant (p<0.05). The nomograms developed could reliably predict the maximal flow rate in young Pakistani men.

Geometry of milk liners affects milking performance in dairy cows.

The geometry of milk liners may affect milking performance and cow comfort as the milk liner is the only part of the milking machine that comes into contact with the teat. To determine the effect of alternative shape of milk liners we compared square (SQR) vs. the conventional round (RND) teat cup liner on milking performance and comfort of dairy cows. Treatment milk liners were randomly allocated to clusters within each side of the 12 a side double up-herringbone dairy shed in a complete randomised block design over two periods. Milking performance data from a total of 10 065 (late stage of lactation and once-a-day milking frequency, LATE) and 18 048 (early stage of lactation and twice-a-day milking frequency, EARLY) milking events were automatically recorded by a DeLaval milk meter, and separately analysed for LATE and EARLY, respectively. In EARLY, cow comfort behaviour was also recorded during afternoon milking sessions. Across the two study periods, average milk flow rate, milk flow rate during 0-15, 15-30 and 30-60 s after cluster attachment, and milk flow rate at cluster take-off were higher in SQR compared to RND treatment. Proportion of time in a milking session with low milk flow rate and duration of milking session were less in SQR compared to RND treatment. However, effect of geometry of milk liner on peak milk flow rate was inconsistent across the two-study periods. Peak milk flow rate was higher (P < 0.001) in SQR than RND in LATE, but higher (P < 0.001) in RND than SQR in EARLY. Stomping and kicking behaviours of cows were similar between treatments. Results of this study suggest that square milk liners potentially improve milking performance, without adverse effect on cow comfort compared to conventional round liners. Long-term, multi-site studies are required to confirm potential teat-end health benefits associated with square milk liners and further verify these results.

Geothermal resources of Hungary: a play-based review

In this paper we review the geothermal resources of Hungary using the geothermal play concept and its scale-dependent hierarchical categorization. The Pannonian Basin belongs to an extensional domain play type, with two main plays: the porous Neogene basin fill sediments and the fractured-karstified Palaeozoic and Mesozoic basement rocks. Both plays can be divided into hydrostatic and overpressured play segments. The most widely utilized play level in the hydrostatic segment of the porous Neogene sediment play comprises laterally extended highly permeable sandstone layers storing low salinity thermal water with average flow rate around 900 l/min and temperatures between 50 °C and 100 °C in the depth range of 1–2 km. The other prosperous play level is represented by the fractured-karstified Mesozoic carbonates in the hydrostatic segment of the basement play having elevated temperatures (90–120 °C) and several thousand l/min flow rates. The play level related to fractured Palaeozoic rocks is less important due to its limited extent. The overpressured segment of the basement play may have high flow rates, but still an untapped resource, where exploitation is limited by high overpressure, high temperature (170–200 °C), and highly saline hot waters.

Assessment of the physiochemical properties and sustainability of locally produced ceramic G-filter in a long term experiment

In India, Ceramic Water Filters (CWF) named G-filters are becoming a point-of-use household water treatment solution. The filter's reliability may be primarily characterized by the filtrate turbidity and microbial removal efficiency. The temperature and moisture gradients of the location affect its performance. This paper describes a 19-week laboratory investigation of G-filters simulating field conditions. The basic objective during the study was to ascertain the effective useable life of the filter. The discharge rate and turbidity reduction ability of the filters are studied in depth. The G-filters were prepared using locally available salty clay and sawdust taken in equal volume fractions. A total of 30 filters with a 9-liter capacity each were used for the experiments. The results showed that CWFs can reduce turbidity effectively. The influent water used for the study had a mean turbidity of 7.65 NTU, which reduced in the range of 0.03 NTU to 1.03 NTU. Over the course of four months, the average flow rate decreased from 1.94 Lh-1 to 0.93 Lh-1. Although a soft brushing of filters improved the filtration rate but that too failed in the long run. Brunauer–Emmett–Teller (BET) nitrogen adsorption–desorption measurements were used to determine the variation in pore size of filters with time. An average pore radius of 2.91 nm was found in the original filter that has not been used for filtration experiments. Moreover, an average pore radius of 1.77 nm, 1.21 nm, and 1.22 nm were reported in G-filters through which 427.5 L, 807.5 L, and 1035.5 L, respectively, of water were passed. This reduction in pore size is attributed to the clogging of pores over a period of time. This study aims to collect performance data to establish a scientific model using statistical analysis for implementing CWF technology in developing nations.

Telemedicine in Pediatric Respiratory Care: Benefits, Challenges, and Future Directions

This study explores the impact of telemedicine on pediatric respiratory care, focusing on its benefits, challenges, and future directions. A mixed-methods approach was employed, involving 150 pediatric patients with chronic respiratory conditions such as asthma and cystic fibrosis, who were randomly assigned to either telemedicine or traditional care groups. The telemedicine group used a digital platform for video consultations, remote monitoring, and health management over a 12-month period. Quantitative data on clinical outcomes, including emergency department visits and hospitalizations, were collected from electronic health records, while patient-reported outcomes were assessed through surveys. Qualitative data were gathered via semi-structured interviews with patients and caregivers. Results indicated that the telemedicine group experienced significantly fewer emergency visits and hospitalizations, higher quality of life scores, better treatment adherence, and greater patient satisfaction compared to the traditional care group. Average oxygen saturation and peak flow rates were also higher in the telemedicine group, and more frequent monitoring alerts were noted.

Techno-economic analysis of the integration of an innovative particle-based concentrating solar power system with a thermally driven cooling system

Stand-alone solar cooling technologies are under development and cannot compete economically with conventional cooling systems. Integration of particle-based concentrating solar power (PBCSP) systems with thermally driven cooling systems can provide an advantage over stand-alone solar cooling systems by providing low-cost, eco-friendly electricity and cooling energy. Consequently, this research proposes to investigate and identify the best configuration for the integrated system deployment to provide electricity and cooling energy in Tabuk province in Saudi Arabia and evaluate the levelized cost of electricity (LCOE) for the particle-based concentrating solar power and the levelized cost of cooling (LCOC) for the thermally driven cooling systems. Tower height and receiver dimensions of the particle-based concentrating solar power are found by performing techno-economic optimization in SolarPILOTTM and SAMTM. The performance of the particle-based concentrating solar power block and the thermally driven cooling systems is evaluated by simulating the thermodynamic model in EESTM. These models are validated by the manufacturers’ datasheets. Cost models are defined to be used in the economic analysis. The exhaust gas double-effect absorption chiller (EGDEAC) is selected as the thermally driven cooling system. The result of thermodynamic performance analysis shows the particle-based concentrating solar power has an annual electricity production of 191 TWh from solar energy alone, with the power block exhaust having an average flow rate of 386 Mg/h and an average yearly exhaust temperature of 378◦C. On the other hand, the exhaust gas double-effect absorption chiller produces an annual cooling energy of 97,461,948 TR-h with an average COP of 1.456. The economic results demonstrate that the proposed system achieves a levelized cost of electricity, and levelized cost of cooling of 6.08 ¢/kWh and 3.77 ¢/TR-h, respectively. When this levelized cost of cooling is compared with the conventional mechanical vapor compression (MVC) cooling system, the result shows that the exhaust gas double-effect absorption chiller is competitive and has one-third of the levelized cost of cooling of mechanical vapor compression. The sensitivity analysis was also made on related influencing factors for the levelized cost of cooling. The analysis shows that the levelized cost of cooling of exhaust gas double-effect absorption chiller is sensitive to the amount of the output cooling energy and the total system cost.

Arrangement and feedback effects of droplet swarms in a parallel microchannel device

Droplet swarms are the dominant form of highly dispersed microdroplets in cavities. During the self-assembly of droplet swarms, the continuous phase is inclined to flow along the path of the minimum resistance, while the arrangement of the droplet swarms seeks to minimize the potential energy, and the two mechanisms compromise in competition. In this paper, the ability of droplet swarms to timely adjust the morphology is measured by the ratio of the average flow rate of the two-phase flow to that of the droplet swarms, thereby clarifying the dominant mechanism of the arrangement of droplet swarms. The arrangement of droplet swarms dominated by different mechanisms and their distribution are introduced, and the prediction method for the arrangement of droplet swarms is proposed. The mechanism underlying the breakup of the microdroplets in the cavity is elucidated, and three modes of the breakup in the cavity are introduced. Furthermore, a resistance model for the microdevice is established to quantify the fluctuations of pressure difference and flow rate resulting from the formation of droplet swarms. The feedback effects of droplet swarms on the uniformity of droplet formation and flow patterns are analyzed, revealing the ideal flow range for the formation of highly dispersed droplets in microchannels. This paper elucidates the arrangement and the feedback effects of droplet swarms, which will guide the application of microdevices in reaction and mass transfer processes.

Index-Based Alteration of Long-Term River Flow Regimes Influenced by Land Use Change and Dam Regulation

The growing population and expansion of rural activities, along with changing climatic patterns and the need for water during drought periods, have led to a rise in the water demand worldwide. As a result, the construction of water storage structures such as dams has increased in recent years to meet the water needs. However, dam construction can bring significant alterations to the natural flow regime of rivers, and it is therefore essential to understand the potential effects of human structures on the hydrological regime of rivers to reduce their destructive impacts. This study analyzes the hydrological changes in the Shahrchai River in response to the Shahrchai Dam construction in Urmia, Iran. The study period was from 1950 to 2017 at the Urmia Band station. The Indicators of Hydrological Alteration (IHA) were used to analyze the hydrological changes before and after regulating, accounting for land use changes and climatic factors. The results revealed the adverse effects of the Shahrchai Dam on the hydrological indices. The analysis showed an increase in the average flow rate during the summer season and a decrease in other seasons. However, the combined effects of water transferring for drinking purposes, a decrease in permanent snow cover upstream of the dam, and an increase in water use for irrigation and agricultural purposes resulted in a decrease in the released river flow. Furthermore, the minimum and maximum daily flow rates decreased by approximately 85% and 65%, respectively, after the construction of the Shahrchai Dam. Additionally, the number of days with maximum flow rates increased from 117 days in the pre-dam period to 181 days in the post-dam period. As a concluding remark, the construction of the Shahrchai Dam, land use/cover changes, and a decrease in permanent snow cover had unfavorable effects on the hydrological regime of the river. Therefore, the hydrological indicators should be adjusted to an acceptable level compared to the natural state to preserve the river ecosystem. The findings of this study are expected to guide water resource managers in regulating the sustainable flow regime of permanent rivers.