Total Leakage Research Articles

Phacoemulsification cataract surgery with different cumulative energy composite parameters in patients with type 2 diabetes mellitus:therapeutic effect and complications

To evaluate the effect of different cumulative energy composite parameters on the outcomes of phacoemulsification cataract surgery in patients with type 2 diabetes mellitus. A total of 252 patients with cataract (involving 252 eyes) and type 2 diabetes mellitus received phacoemulsification cataract surgery in our hospital between January, 2017 and June, 2019. The patients were divided into group A (150 cases) and group B (102 cases) for cataract phacoemulsification with cumulative energy composite parameters of 8 and 10, respectively, and 90 nondiabetic patients received cataract phacoemulsification with a cumulative energy composite parameters of 10 served as the control. The macular thickness, best corrected visual acuity, visual acuity, and postoperative leakage in the 3 groups were evaluated at 1 week, 1 month, and 3 months after the surgery. The visual acuity was significantly improved after phacoemulsification better in all the 3 groups. At 3 months after the surgery, the proportions of patients with visual acuity ratio < 0.1 or >1.0, macular thickness, best corrected visual acuity and permeability differed significantly between groups A and B (P < 0.05), but not between group A and the control group (P > 0.05). At 1 month and 3 months after the surgery, the proportion of patients with visual acuity ratio < 0.1 was significantly lower and the rate of visual acuity ratio >1.0 was higher in group A than in group B. At 1 month after the operation, the total leakage rate in group A (31.1%) was higher than that in the control group (21.1%) but comparable with that in group B; at 3 months, the total leakage rates were significantly lower in group A than in group B (10.0% vs 32.4%, P < 0.05), and the leakage resulted mainly from local and diffuse permeation. Phacoemulsification can effectively improve the visual acuity of cataract patients especially in non-diabetic patients. A lower cumulative energy composite parameter achieves better outcomes in type 2 diabetic patients with cataract. The macular thickness, local infiltration and diffuse leakage can be used as indicators for assessing visual recovery and stabilization after phacoemulsification.

357 Wound Chambers for Porcine Wound Healing Research

Standardized and reproducible animal models are crucial in medical research. Pigs are commonly used in burn wound healing studies because of the large surface area and similarities to human skin. However, the most significant challenge with porcine wound models remains the inability to isolate individual wounds and the high risk of cross-contamination. The aim of this study was to develop wound chambers for burn wound healing research. A porcine partial-thickness burn wound (PTBW) model was first developed by creating 16 burn wounds on the back of a female Yorkshire pig using a brand heated to 200°C and applied with 1kg of force. Different branding durations were attempted (40s, 10s, 5s, or 2s, n=4 per group) to determine the appropriate technique to obtain PTBWs. Biopsies were taken 30 minutes after burning for histology. Wounds were debrided two days later followed by dressing changes three times a week for 14 days to monitor healing was using photographs and tracings. Wound chambers were engineered as a two-piece structure (base and cover) to surround, isolate and cover individual porcine wounds. The wound chamber base was created using a stoma click barrier secured using tissue adhesive, moldable ring seal and staples. The wound chamber cover was created by placing a transparent film dressing over the base’s ring and securing it with a stoma pouch. Based on the first experiment, 15 PTBWs were created on the back of a female Yorkshire pig to test the wound chambers and assess total wound closure, wound contraction, leakage, and cost. In the first pig (PTBW model), the optimal branding time to develop PTBWs was determined clinically and histologically to be 10s showing moderate-to-deep partial-thickness. In the second pig (wound chamber model), the wound chambers were easy to apply and maintain, and were impervious to the pig’s activity. All wounds were closed by week 5 and no wound chamber leakage was observed. The animal tolerated them well. The average cost per wound chamber was $117.20. This study demonstrates that these wound chambers provide a means for controlled monitoring, sampling and treatment of the wound in vivo, allowing a reduction in cross-contamination and an increase in standardization. These wound chambers can be a standardized reproducible model for porcine wound healing research.

Effect of Soil Drought on Biomass Production, Physiological Attributes and Antioxidant Enzymes Activities of Potato Cultivars

The effects of water deficit on the activity of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POX), and also on total antioxidant capacity, ion leakage, proline content, chlorophyll fluorescence, gas exchange, chlorophyll and carotenoid content and plant dry mass of potato cultivars (Solanum tuberosum L.) were investigated. For this purpose, the response of ten potato cultivars (Agria, Arinda, Marfona, Banba, Born, Sante, Milva, Satina, Jelly and Spirit) was studied under two irrigation regimes (70 and 20% of soil available water). Water deficit increased the activity of antioxidant enzymes, ion leakage and proline content but decreased total antioxidant capacity, Fv/Fm, gas exchanges, chlorophyll, carotenoid and plant dry mass in all potato cultivars. Based on stress tolerance index (STI), Agria and Born were the most tolerant and sensitive cultivars to water stress, respectively. Positive correlations were found between total antioxidant capacity and the activities of CAT, APX and POX under control irrigation. Proline content positively correlated with plant dry mass and negatively with photosynthesis, transpiration and carbon dioxide concentration in the sub-stomatal chamber under water deficit treatment. The highest increases in ion leakage under water deficit were observed in the most sensitive cultivars. The results of this experiment, therefore, showed that proline accumulation and ion leakage may be related to water stress tolerance of potato cultivars. Also, increased chlorophyll and carotenoid content in resistant cultivars supported potato plants to tolerate water deficit.

A major leak in a crude oil tank: Predictable and unexpected root causes

A 2000 m3 washer tank at a crude oil treatment plant suffered a structural collapse, involving total loss of integrity. A fast fracture initiated in a sector of the shell with a severe thickness reduction due to combined internal and external corrosion. The fracture bent and propagated horizontally, at the shell-roof intersection and at the joint between second and third courses, causing the almost instant opening of a large window. Due to the large initial leakage flow, the containment enclosure wall could not hold the spilled mixture of water and crude oil. The fast leaking wave damaged the breakwaters at the top of the wall, overpassed the enclosure and pushed out a sliding gate, thus causing total liquid leakage. Fracture and computational fluid dynamics models were developed to understand the origins of the failure, as well as to reconstruct the sequence of events. Deficiencies in tank construction, maintenance adequacy, and corrosion prevention were found to be the main root causes of the failure.

Genetic algorithm optimized non-destructive prediction on property of mechanically injured peaches during postharvest storage by portable visible/shortwave near-infrared spectroscopy

The melting-flesh peach (Prunus persica, cv. 'Baihua') tends to rapidly decay after harvest in summer with a short after-ripening period. Although the use of preservatives can inhibit the growth of microorganisms, collisions during transportation greatly affect the shelf life for subsequent sales. To build a high-accuracy model to predict the inner physiological status of mechanically injured peaches during postharvest storage, visible/shortwave near-infrared (Vis/SWNIR) diffuse reflection spectra (300–1150 nm) were acquired for analysis. With 840 samples, two drop heights (30 cm and 60 cm) were applied to study the variations in total soluble solids (TSS) polyphenol oxidase (PPO), malondialdehyde (MDA) and relative electrolyte leakage (REL) by percussive tests. After multiplicative scatter correction and Savitzky-Golay smoothing pretreatments, optimal feature selections from a total of 1024 wavelengths were determined using genetic algorithm (GA) in PLS modeling. For TSS, the best correlation (rp) is 0.89, root mean square error of prediction (RMSEP) is 0.40 and relative percent deviation (RPD) is 2.94. For PPO, the best rp is 0.71, RMSEP is 20.34 and RPD is 2.75. For MDA, the best rp is 0.83, RMSEP is 0.17 and RPD is 1.90. For REL, the best rp is 0.92, RMSEP is 1.42 and RPD is 2.44. Through several verifications, the GA-PLS models showed good imitative effects and high precisions. They could predict the condition of peaches with minor injury, which are difficult to detect with the naked eye, to reduce loss in practical production.

Experimental Study of Minimizing Heat Leakage of Cryogenic Transfer Lines

In this paper, a three-channel coaxial liquid helium pipe with three support structures and typical MLI materials was designed. Heat leakage of cryogenic transfer lines has been experimentally analyzed for MLI with different layer density & number of layer and three support structures, based on an experimental cryogenic transfer lines test platform. The experimental results show that the minimal heat leakage of MLI was 0.488 W/m under the conditions of MLI with 50 layers and 25 layers cm-1.The heat leak of two-plate support structure is 0.200 W per one, which decreases by more than 54% comparing to triangle support. After optimization, the total heat leakage of liquid helium cryogenic transfer line was reduced to 0.688 W/m, which has been successfully applied in 250 W @ 4.5 K helium cryogenic refrigerator.

A Hardware and Software Complex for Remote Monitoring of a High-Voltage Line Arrester under Operating Voltage

A hardware and software complex for remote monitoring of high-voltage line arresters (HVLAs) under operating voltage has been developed. The complex is a two-level distributed system with autonomous monitoring points. The main functional units of the complex are a block of current sensors, a registration and communication device, a self-contained power supply, a receiving base station, and an automated workplace (AWP). Apart from the total leakage current and number of operations, the complex registers the amplitude and duration of the HVLA lightning pulse. These parameters may be used for the assessment of the HVLA residual resources and making a decision as to the feasibility of its further operation. An optical sensor on the basis of a bismuth silicate crystal is used as a sensor of an impulse current; its operating principle is based on the Faraday linear magnetooptic effect. The advantage of the bismuth silicate crystal is the feasibility of the noncontact measurement of the pulse magnetic field strength, high temperature stability and high noise immunity. The standard of the wireless LoRa communication was selected for the transmission of information; its advantage is a high noise immunity, larger range of radio signal transmission (up to 10 km), low energy consumption, and high penetrating capacity penetrability. A solar battery with a standby power supply—a rechargeable battery—was selected as the self-contained power supply. Program modules for receiving and transmission of information and AWP were developed. The hardware and software system allow preventing the emergency situations on the high-voltage line, planning more service and repair operations more effectively and efficiently, and starting the operation of HVLAs based on technical conditions.

Guidelines for landfill gas emission monitoring using the tracer gas dispersion method

Landfill gas often containing 50–60% methane, is generated on waste disposal sites receiving organic waste. Regulation requires that this gas is managed in order to reduce emissions, but very few suggestions exist as to how management activities are monitored, what should be set up to ensure this management and how criteria should be developed for when monitoring activities are terminated. Methane emission monitoring procedures are suggested, based on a robust method for measuring total leakage from the site; additionally, quantitative measures, to determine the efficiency of the performed emission mitigation, are defined. The tracer gas dispersion measuring technique is suggested as the core emission measurement methodology in monitoring plans for methane emissions from landfills and a guideline for best practice measurement performance is presented. A minimum methane mitigation efficiency of 80% is suggested. Finally, several principles are presented on how criteria can be developed for when a monitoring program can be terminated. Three of the suggested principles result in comparable completion criteria of about 1–3 kg CH4/h for a small landfill (an area of 4 ha).

Characterization and Modeling of Gigarad-TID-Induced Drain Leakage Current of 28-nm Bulk MOSFETs

This paper characterizes and models the effects of total ionizing dose (TID) up to 1 Grad(SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) on the drain leakage current of nMOSFETs fabricated with a commercial 28-nm bulk CMOS process. Experimental comparisons among individual nMOSFETs of various sizes provide insight into the TID-induced lateral parasitic devices, which contribute the most to the significant increase up to four orders of magnitude in the drain leakage current. We introduce a semiempirical physics-based approach using only three parameters to model the parallel parasitic and total drain leakage current as a function of TID. Taking into account the gate independence of the drain leakage current at high TID levels, we model the lateral parasitic device as a gateless charge-controlled device by using the simplified charge-based Enz-Krummenaker-Vittoz (EKV) MOSFET model. This approach enables us to extract the equivalent density of trapped charges related to the shallow trench isolation oxides. The adopted simplified EKV MOSFET model indicates the weak inversion operation of the lateral parasitic devices.

Robustness to Voltage Noise With Ring Oscillator Clocks

Voltage noise is the main source of dynamic variability in integrated circuits and a major concern for the design of power delivery networks (PDNs). Lower supply voltages were made possible with technology scaling, but power density was also increased. Consequently, power integrity became a key factor in the design of reliable high performance circuits. Ring oscillators clocks (ROCs) have been proposed as an alternative to mitigate the negative effects of voltage noise. However, the effectiveness highly depends on the design parameters of the PDN, power consumption patterns, and spatial locality of the ROC within the clock domain. This paper analyzes the impact of the PDN parameters and ROC location on the voltage noise and the robustness achieved by using ROCs. The capability of reacting instantaneously to large voltage droops makes ROCs an attractive solution, which also allows to relax the constraints required for the PDN design. The experiments show that up to 83% of the margins for voltage noise and up to 27% of the total leakage power can be reduced by using ROCs. In addition, PDN simplifications are possible, with fewer power interconnections or package decoupling capacitors of lower quality. Tolerance to voltage noise and related benefits can be increased with multiple ROCs.

Using heat as a tracer to quantify surface water and groundwater interactions in the Baiyangdian wetland

Surface water and groundwater interactions play an important role in hydrological cycle in a wetland ecosystem. Understanding its mechanism and interaction magnitude imposes significant effects in wetland protection and management. In this study, a heat tracer method was taken in the Baiyangdian wetland as a case and temperature time-series data were collected for surface water and wetland sediment of 0.2 m, 0.6 m and 1 m respectively in 3 monitor sites. Then, a one-dimensional vertical steady heat transport model was applied to estimate surface water inflows to groundwater. The results showed that the leakage rates were 0.04-0.29 mm/d and had a spatial and temporal variation. In the same monitor site, the leakage rate was higher in winter than it in summer. A total leakage amount for the Baiyangdian wetland was evaluated as 8.61 million m3/d. The surface water leakage resulting from the model was subject to several uncertainties including sediments inhomogeneity and the impact of non-ideal conditions. Despite the uncertainties of the model, when correctly applied, heat tracer method is able to provide detailed information on the spatial and temporal distribution of surface water leakage.

Система мониторинга ограничителей перенапряжений на линиях электропередачи

The hardware and software complex of remote monitoring of the high voltage line arresters (HVLA) under operating voltage is developed. The complex is a two-level distributed system with autonomous monitoring points. The main functional units of the complex are: a block of current sensors, a registration and communication device, an autonomous power supply, a receiving base station and an automated workplace (AWP). In addition to measuring the total leakage current and the number of trips, the system records the amplitude and duration of the lightning current pulses flowing through the HVLA. These parameters can be used for assessment of the HVLA residual resource and making decision on a possibility of its further operation. For information transfer the standard of a wireless communication LoRa which advantages are is chosen: high noise immunity, larger range of transfer of a radio signal (up to 10 km), low energy consumption and high penetration. Program modules are developed for the device of reception and transfer of primary information and an automated workplace. The hardware and software system will allow to prevent emergence of a contingency situation on power lines, quickly and more efficiently to plan service and repair work, to pass to operation of HVLA on technical condition.

Modelling the Leakage Rate and Reduction Using Minimum Night Flow Analysis in an Intermittent Supply System

A significant portion of the water supplied to people doesn’t reach its valid users but instead leaks out of the distribution network, causing water wastage, revenue loss and contamination risks. This paper analyses the leakage rate, leakage components and leakage reduction potential. A minimum night flow (MNF) analysis was carried out on a district metered area (DMA) in an intermittent supply system in Zarqa, Jordan. Leakage was modelled and leakage reduction policies were analysed. Results show that MNF occurs at night or during day time depending on the water levels in customer tanks, implying that one-day MNF analysis cannot be carried out in intermittent supplies and the estimation of the legitimate consumption during MNF is more influential. The potential water savings of the different leakage reduction measures (pressure management; leakage detection; response time minimization) are separately analysed in the existing models in the literature, leading to significant overestimation of the total leakage reduction potential, while these measures are influencing each other. Pressure reduction lowers the failure frequencies but limits the potential of leakage detection surveys, as leaks will become harder to hear and detect. Investigating the inter-dependency relations of these measures is therefore essential for reasonable leakage reduction modelling and planning.

Constant-head test at a partially penetrating well in an aquifer-aquitard system

An analytical model for describing pumping induced drawdown by constant-head test at a partially penetrating well in a leaky confined aquifer is developed by treating the leakage of aquitard storage as an interface phenomenon rather than an volumetric effect, which is the novel and never developed so far. Three different cases of remote lateral boundaries are considered in the model. The new drawdown solution in Laplace space is obtained and inverted into time-domain solution utilizing the Stehfest method. The (semi-)analytical solutions for well discharge are then obtained under three different cases. Analytical solutions in Laplace and time domains are developed for calculating the (total) leakage rate and volume across the aquitard-aquifer interface due to constant-head test at a partially penetrating well in a leaky confined aquifer, and such solutions are of great use for groundwater resource management. Based on the newly developed solutions, the distribution of wellbore flowrate and aquitard leakage are explored and the sensitivity analysis is conducted to identify the most important controlling factor. The sensitivity analysis shows that the wellbore flowrate and the drawdown in infinite (Case 1), finite (Case 2), and closed (Case 3) leaky confined aquifer systems are both sensitive to the variation of well partial penetration, well radius, and aquifer anisotropic ratio during the whole pumping period and they are most sensitive to the change of outer boundary distance at late time for Case 3. The effect of the outer boundary on the drawdown or wellbore flowrate is more significant for a shorter outer boundary distance.

A tritium permeation ‘short cut’ for plasma-facing components of fusion reactors

In ITER and other fusion reactors, plasma-facing components (PFCs) will be subjected to intense plasma/neutral fluxes and tritium (T) permeation issue will be raised. In the present work, first-of-a-kind experiments on hydrogen isotope (D) transport through ITER-like PFC mock-ups have been demonstrated in a linear plasma facility. 8 mm thick W tiles with 0.5 mm gaps are installed on structural materials and exposed to D plasmas. The angle between the gaps and the magnetic field line is set to be 5° to ensure the structural materials behind W are not exposed to charged D ions from plasma. When plasma is started up, the sample mock-ups are found to be penetrated by D within tens of seconds, suggesting that D can penetrate through heat sink of PFCs without passing through the thick W armor, i.e. the gaps act as a hydrogen isotope leakage ‘short cut’. To make a straightforward comparison of permeation flux for these materials, direct D plasma-driven permeation (PDP) experiments through W and structural materials are performed as well. The measured permeated D fluxes through structural materials are found to be orders of magnitude higher than that of W, indicating T transport from the gaps of PFCs may contribute a remarkable fraction of total leakage in reactors. In the latter part of this paper, a solution to address the permeation issue is proposed.

Analysis of CMOS Comparator in 90nm Technology with Different Power Reduction Techniques

To reduce power consumption of regenerative comparator three different techniques are incorporated in this work. These techniques provide a way to achieve low power consumption through their mechanism that alters the operation of the circuit. These techniques are pseudo NMOS, CVSL (cascode voltage switch logic)/DCVS (differential cascode voltage switch) &amp;amp; power gating. Initially regenerative comparator is simulated at 90 nm CMOS technology with 0.7 V supply voltage. Results shows total power consumption of 15.02 μW with considerably large leakage current of 52.03 nA. Further, with pseudo NMOS technique total power consumption increases to 126.53 μW while CVSL shows total power consumption of 18.94 μW with leakage current of 1270.13 nA. More then 90% reduction is attained in total power consumption and leakage current by employing the power gating technique. Moreover, the variations in the power consumption with temperature is also recorded for all three reported techniques where power gating again show optimum variations with least power consumption. Four more conventional comparator circuits are also simulated in 90nm CMOS technology for comparison. Comparison shows better results for regenerative comparator with power gating technique. Simulations are executed by employing SPICE based on 90 nm CMOS technology.

Percutaneous Vertebral Augmentation for Osteoporotic Vertebral Compression Fracture in the Midthoracic Vertebrae (T5-8): A Retrospective Study of 101 Patients with 111 Fractured Segments

Data reporting percutaneous vertebroplasty (PVP) or percutaneous balloon kyphoplasty (PKP) application to the midthoracic vertebrae remain limited. This study aimed to summarize our experiences and explore the efficacy and safety of PVP or PKP in dealing with osteoporotic vertebral compression fracture (OVCF) in the midthoracic vertebrae. Patients receiving PVP or PKP for midthoracic OVCF in our institution from January 2015 to January 2018 were retrospectively enrolled. All patients were grouped according to cement augmentation procedure types, surgical approaches, and puncture routes. All patients underwent a postoperative follow-up of 2-36 months. Visual analog scale (VAS) and ECOG Scale of Performance Status scores were evaluated pre- and postoperatively. Cement distribution and rate of cement leakage were assessed by radiographs. Associations of these variables and clinical scores and radiographic indices were analyzed. A total of 101 consecutive patients with 111 fractured centrums were enrolled. Both VAS and ECOG Scale of Performance Status scores of all patients decreased significantly after the operation, and progressively decreased at the final follow-up. The cement distribution of the bipedicular group was significantly better than the unipedicular group, but the total leakage rate of the former (71.7%) was significantly higher than the latter (43.1%). The rate of epidural cement leakage in the PKP group (5.4%) was significantly lower than that of the PVP group (20.3%), whereas the left puncture group (28.6%) was significantly higher than that of the right puncture group (2.7%). PKP and a bipedicular approach can help improve cement distribution and reduce the epidural cement leakage rate and therefore should be preferred over PVP or a unipedicular approach in OVCF of the midthoracic vertebrae.

Parameter optimisation of support vector machine using mutant particle swarm optimisation for diagnosis of metal-oxide surge arrester conditions

ABSTRACTThis paper proposes an enhanced support vector machine (SVM), whose parameters are optimised by a novel mutant particle swarm optimisation (mutant PSO) algorithm to identify metal-oxide surge arrester conditions. The total leakage current and its resistive component under different arrester conditions are obtained and then are inputted into a multilayer SVM for the purpose of fault identification. Then, a mutant PSO-based technique is investigated to increase the classification accuracy as well as the training speed of the SVM classifier. The proposed technique has been tested on an actual data set obtained from Taipower Company to monitor five arrester operating conditions, including normal (N), pre-fault (A), tracking (T), abnormal (U) and degradation (D). Furthermore, to demonstrate the effectiveness of the proposed mutant PSO, the obtained results are compared to those obtained by using cross-validation method, genetic algorithm and particle swarm optimisation.

Short Communication: Health Interventions in Volcanic Eruptions—Community Wearability Assessment of Respiratory Protection against Volcanic Ash from Mt Sinabung, Indonesia

Inhalation of ash can be of great concern for affected communities, during and after volcanic eruptions. Governmental and humanitarian agencies recommend and distribute a variety of respiratory protection (RP), commonly surgical masks but, also, industry-certified N95-style masks. However, there is currently no evidence on how wearable they are within affected populations or how protective wearers perceive them being against volcanic ash (which will influence the likelihood of uptake of recommended interventions). Volunteers living near Mt. Sinabung, Sumatra, Indonesia, participated in a field wearability study, which included a high-efficiency mask certified to industry standards (N95-equiv.); a standard, pleated surgical mask (Surgical); a Basic flat-fold mask (Flat-fold), and the surgical mask plus a scarf tied over the top (Surgical Plus) to improve fit. These types of RP had all performed well during earlier laboratory filtration efficiency tests. The N95-equiv. mask had performed significantly better than the other RP in the subsequent total inward leakage volunteer trials, whilst the Flat-fold and Surgical masks performed poorly, letting in a third of PM2.5 particles (data published elsewhere). Thirty volunteers wore each mask for a 15-min walk before being asked to rate the comfort, breathability and perceived protection and fit of each. After wearing all of the masks, volunteers compared and identified their preferred type of protection. The feedback received from the volunteers suggested that the Surgical Plus and N95-equiv. masks were rated as being significantly hotter and more humid than other masks. The Flat-fold was rated to have better breathability than the other masks. The N95-equiv. mask was ranked as providing the best level of effectiveness of the four masks tested. Ultimately, when asked which type of mask they would choose to wear during ashfall, 33% selected the Flat-fold mask due to its comfort and simplicity, with the Surgical Plus being the least likely to be chosen of the four tested. The study findings are of benefit to agencies who need to make informed decisions on the procurement and distribution of RP for use by those affected in future eruptions and the provision of advice to communities on their usage.

Quantifying CO2 Leak Rates in Aquatic Environments

The Daylesford region of Victoria (Australia), is a region of natural CO2 seepage. Small bubble streams of CO2 are released into ephemeral river beds proximal to mineral springs that contain high dissolved CO2 content. We study four sites of CO2 degassing to (i) establish the characteristics of CO2 seepage caused by transport to surface of CO2-rich water, (ii) provide an estimate of CO2 flux in the region, and (iii) investigate seasonal effects on CO2 seepage. We observe that bubbling behavior varies considerably between sites, including the number and distribution of bubbling points, and bubble stream the continuity. Total CO2 seep rates at each site were low (< 20 kg/d) but varied substantially between different sites. There were no obvious indicators of total emission rate; the bubble density or other characteristics at the highest emission seep were not remarkably different to the smaller seeps. We find that the total CO2 emission varies inconsistently with season, with some seep rates increasing and other decreasing in the dry season when water levels are lower. We find there are challenges in quantifying the total gas leakage at sites of highly localized and intermittent degassing. Our work has implications for detecting and quantifying leaks from engineered CO2 storage sites which emerge in aqueous environments, which could be these are marine or terrestrial (lakes or rivers).