Cause Of Leakage Research Articles

Microbiologically influenced corrosion: a review of the studies conducted on buried pipelines

AbstractBuried pipelines are essential for the delivery of potable water around the world. A key cause of leaks and bursts in these pipelines, particularly those fabricated from carbon steel, is the accelerated localized corrosion due to the influence of microbes in soil. Here, studies conducted on soil corrosion of pipelines' external surface both in the field and the laboratory are reviewed with a focus on scientific approaches, particularly the techniques used to determine the action and contribution of microbiologically influenced corrosion (MIC). The review encompasses water pipeline studies, as well as oil and gas pipeline studies with similar corrosion mechanisms but significantly higher risks of failure. Significant insight into how MIC progresses in soil has been obtained. However, several limitations to the current breadth of studies are raised. Suggestions based on techniques from other fields of work are made for future research, including the need for a more systematic methodology for such studies.

Analysis the cause of leakage and repair of floor plates diesel fuel tank 20-D-2 at PT BADAK NGL Indonesia

PT. BADAK Natural Gas Liquefaction or better known as PT. BADAK NGL is a liquefied natural gas (LNG) company in Indonesia with installed capacity 22.5 MPTA of LNG. PT BADAK NGL has LNG, LPG, condensate, and diesel fuel storage tanks. There are two diesel fuel tanks available for supporting diesel equipment such as turbine diesel, marine boats, and vehicles. One of the diesel fuel tank, named 20-D-2, was constructed in 1975 based on standard API 650-Welded Tanks for Oil Storage. In 1996, after being operated for 21 years, plate replacement was needed on the tank floor and had been done as well. But in 2017, during five years of periodic inspection, severe corrosion was found again on the plate of the tank floor. In this paper, the effort to investigate the failure and plate repairment was reported. Visual observation at internal and external side on the plate of the tank floor was conducted based on NDT method (Non Destructive Testing) testing with MFL (Magnetic Flux Leakage). Plate thickness measurement of tank floor was also conducted with UT (Ultrasonic Testing). In addition, chemical analysis of residual fuel on the tank was performed to investigate sulphur concentration that potentially corrodes the plate. Scanning Electron Microscopy (SEM) was also performed to investigate the plate surface that has been corroded. Based on the analysis above, it was known that the leakage of 20-D-2 tank floor was caused by pitting corrosion, general corrosion and crevice corrosion due to rainwater that accumulated on the bottom of tank floor. Direct contact among rain water-soil-plate of tank floor was identified as the main cause of the leakage of tank floor. After leakage mechanism was identified as well, an appropriate method could be formulated to repair the tank to avoid the leakage.

Cause Analysis of Leakage in 316L Stainless Steel Heat Exchanger

A large area of leakage occurred in plate heat exchanger of a power plant. The causes of leakage were analyzed by means of appearance analysis, chemical composition analysis, microstructure detection and energy spectrum analysis. The results show that Cl ion exists in the environment of the leaking heat exchanger, which has strong corrosiveness to austenitic stainless steel. At the same time, there are machining residual stress and internal stress produced by internal medium in the heat exchanger, which lead to stress corrosion and cracking.

Fatigue failure analysis of dented pipeline and simulation calculation

Natural gas pipeline leaks may cause considerable damage to people, properties, and the surrounding environment. This study investigates a dent leak in a gas pipeline in China that has operated for six years. The failure pipe section meets American Petroleum Institute (API) specification 5L-2012 standard for carbon steel pipelines. The cause of leakage is evaluated not only through visual examination, micromorphology observation, structural deformation analysis, and residual stress measure of the dented region near the leak point of the pipe body, but also through finite element analysis on the deformation and stress of the pipe under different loads. The dent formation is related to rocks during pipeline laying. Under the combined effect of external load and internal pressure, the maximum equivalent stresses of the dented edge at the outer wall, bulge top of the inner wall, and dented edge of the inner wall are greater than the yield stress of the material. Moreover, micro-crack formation occurs due to the maximum deformation at the bottom of the dent and the maximum equivalent stress on top of the inner surface bulge. Under alternating stress, microcracks gradually expand until they penetrate the wall thickness, and thereby cause pipeline leakages.

Mechanistic modeling of CO2 well leakage in a generic abandoned well through a bridge plug cement-casing gap

Both known and unmapped plugged and abandoned wells are potential leakage pathways for CO2 from geologic carbon sequestration (GCS) sites. Although many abandoned wells have cement bridge plugs installed to prevent leakage, the seal between the cement and the inner casing wall is subject to failure. In this study, we carried out detailed T2Well simulations of cases of sudden non-Darcy flow of CO2 and brine leakage up the gap between a cement plug and the inner steel casing wall that becomes a fully connected flow path during the post-injection period. The goal of our study was two-fold: (1) to understand the dynamics, rates, and the characteristic temporal signals associated with the onset of leakage through various gap-aperture sizes, and (2) to suggest potential monitoring strategies based on the findings. Simulation results show that the leakage of CO2 and brine upward is transient with interesting phase interference behavior. Time-dependent oscillatory flows with varying pressure, temperature, and flow rates of CO2 and brine show strong dependence on gap aperture. Phase-change and decompression lead to very low temperatures at the top of the well for gap apertures larger than 4 mm suggesting that remote thermal monitoring at the ground surface may be an effective way of monitoring even if well locations are not known a priori. Pressure in the well is also indicative of CO2 leakage. The temporal patterns of changing temperature and pressure may be useful diagnostic signals for leakage detection. Finally, these transient leakage signals may provide information on the cause of leakage and/or characteristics of the flow path that could inform effective remediation design and execution approaches.

Elucidation of leak-resistance DNA hybridization chain reaction with universality and extensibility.

Hybridization chain reaction (HCR) was a significant discovery for the development of nanoscale materials and devices. One key challenge for HCR is the vulnerability to background leakage in the absence of the initiator. Here, we systematically analyze the sources of leakage and refine leak-resistant rule by using molecular thermodynamics and dynamics, biochemical and biophysical methods. Transient melting of DNA hairpin is revealed to be the underlying cause of leakage and that this can be mitigated through careful consideration of the sequence thermodynamics. The transition threshold of the energy barrier is proposed as a testing benchmark of leak-resistance DNA hairpins. The universal design of DNA hairpins is illustrated by the analysis of hsa-miR-21-5p as biomarker when used in conjunction with surface-enhanced Raman spectroscopy. We further extend the strategy for specific signal amplification of miRNA homologs. Significantly, it possibly provides a practical route to improve the accuracy of DNA self-assembly for signal amplification, and that could facilitate the development of sensors for the sensitive detection of interest molecules in biotechnology and clinical medicine.

High voltage GaN p‐n diodes formed by selective area regrowth

GaN p-n diodes were formed by selective area regrowth on freestanding GaN substrates using a dry etch, followed by post-etch surface treatment to reduce etch-induced defects, and subsequent regrowth into wells. Etched-and-regrown diodes with a 150 μm diameter achieved 840 V operation at 0.5 A/cm 2 reverse current leakage and a specific on-resistance of 1.2 mΩ·cm 2 . Etched-and-regrown diodes were compared with planar, regrown diodes without etching on the same wafer. Both types of diodes exhibited similar forward and reverse electrical characteristics, which indicate that etch-induced defectivity of the junction was sufficiently mitigated so as not to be the primary cause for leakage. An area dependence for forward and reverse leakage current density was observed, suggesting that the mesa sidewall provided a leakage path.

Analysis of the causes of leakages and preventive strategies of boiler water-wall tubes in a thermal power plant

The reasons for the failures of a boiler water-wall tube used in the thermal power plant were investigated in this paper. The material of water-wall tube was made of medium-carbon steel, SA-210 Grade C, which is pearlitic heat-resistant steel with a working temperature lower than 500 °C and is widely used in boilers tubes. To investigate the causes of failure, various techniques including macroscopic inspection, chemical composition analysis, mechanical performance testing, optical microscopy observation and Energy Dispersive Spectroscopy (EDS) were carried out. Corrosive products were found on the inner wall of the tube’s bulge positions. The thickness of the tube wall covered by the corrosive products reduced due to the corrosion. The boiler water quality was analyzed and it was found that there was excessive Sodium Hydroxide (NaOH), which was the main corrosion-induced substance. Metallographic examination results showed that the microstructure in the corroded area has aged. Based on the analysis results, failure causes can be drawn: excessive NaOH in the boiler water was the main reason for the corrosion. The characters of alkaline corrosion products provided the condition that corrosion can proceed continuously which caused the thinning of the water-wall tube. As the process proceeds, it reduces performance of the tube and creates bulge which finally causes leakage.

Determination of aircraft hydraulic system pipeline leak cause

The purpose of this article is to determine the cause of leak of the aircraft hydraulic system pipeline detected during pre-flight flight preparation. Results of spectral analysis of material, mechanical testing, analysis of defect structure by optical fractography and metallographic analysis are presented.

A550 Indocyanine Green Mesenteric Angiography as an Intraoperative Assessment of Bowel Perfusion in Revisional and Primary Bariatric Operations. Assessment of 50 Cases, Operative Findings and Surgical Interventions Taken

Insufficient blood flow has been hypothesized as a cause of leakage in bariatric surgery. Inadequate or decreased blood flow of the roux limb, the gastrojejunostomy, the angle of Hiss and the duodenal-ileostomy in bariatric operations can be assessed via Indocyanine Green flourescent imaging intraoperatively. We assessed the usefullness of Indocyanine green florescent blood flow imaging of these structures during Roux Y gastric bypass, duodenal switch and sleeve gastrectomy. Both primary and revisional procedures were studied.

Tribological behaviors of PTFE-based composites filled with bronze microparticles

This research article deals with commercial polytetrafluoroethylene (PTFE)-based composites filled with 30% of bronze microparticles. This shade is used as guide rings in hydraulic cylinders. After a certain number of slip cycles, seal wear is one of the main causes of leaks in the hydraulic systems. To solve this problem, it is essential to act on the seal materials to increase its lifetime and consequently the lifetime of hydraulic systems. Excessive pressure on the seal causes a significant wear while a light contact causes lubricant leak. For both situations, we have a failure of the system. For this reason, it is necessary to have a perfect contact between the seal and the metal surface and simultaneously with minimal wear. This problem is the subject of our research works. We analyze, in this article, the tribological behavior of a PTFE/bronze composite under dry and lubricated sliding conditions for different frequencies and loads. An alternating linear motion ball/plane tribometer has been used to characterize friction and wear behavior of the material. Micrographic observation of wear track was taken with the optical microscope. The results showed the good friction behavior of material for low values of loads and frequencies and essentially for 33 N of load with 1 Hz frequency or for 81 N as normal load with 0.75 Hz frequency as well as lubrication improve the wear rate of the PTFE/bronze composite. Under lubrication, load and frequency become inversely proportional to friction coefficients.

Explosion in gas pipeline: Witnesses' perceptions and expert analyses' results

The failure of a 24“natural gas pipeline buried in the 1960s led to a blowout followed by fire. The damage caused the breakage and expulsion of 20 meters of tube; flames reached 30 meters high. The break occurred at the edge of a high transit route, in the opposite site of a thermoelectric plant, and under its high-voltage lines. The break was a consequence of a fracture propagated from a pre-existing defect in the reinforcement weld toe of a 3” connection to a nearby village, made 20 years before. The preexisting defect propagated from small weld anomalies, due to external loads related to soil instabilities: removal of top soil for pipe recoating and flooding due to extraordinary rains paired with the recent construction of a highway that distorted normal water flows. Lessons were also learned in terms of the role of witness recounts. Even after root causes were technically established, responsibility was erroneously attributed to high voltage cables (in the ignition of the gas cloud) and dynamic loads from traffic (as cause for leak), due in large part to the credibility given to initial descriptions. Witnesses identified three events: (1) a noise associated with the blow-out, (2) noise and flashes associated with electrical arcing and (3) the final explosion of the gas cloud, although they did not agree on the sequence of the first two events. The immediacy of the three events and the witnesses´ different places and distances from the blowout site justify the differences of time between their perceptions of light and sound.

Corrosion Failure Analysis of the Convection Part of District Heating Peak Load Boiler, 지역난방 첨두부하보일러 대류부 부식 파손 분석

Corrosion failure in the convection part of peak load boiler (PLB) of the district heating system led to water leakage. Herein, Internal Rotary Inspection System (IRIS) inspection was employed to examine wall thinning and the cause of leakage in the flue tube. The corrosive products of the turbulator and tube were investigated using scanning electron microscope combined with energy dispersive spectroscopy, X-ray diffraction, and inductively coupled plasma (ICP). Majority of the serious corrosion damage was observed near the turbulator located in the upper flue tube. ICP analysis of the boiler water revealed oxide formation of sodium chloride in the lower end part of the flue tube. A cross-sectional view of the turbulator revealed the presence of double-layers of the oxide film, indicating environmental change during operation associated with water leakage. The outer surface of the turbulator consisted of the acid oxides such as NOx and SOx along with sodium and chloride ions. Dew-point corrosion is hypothesized as the main cause for the formation of acid oxides in the region of contact of the flue tube and the turbulator.

Identification of sealing potential through fault seal analysis: a case study of Badin area, Lower Indus Basin, Pakistan

The sealing potential of a fault can be originated from reservoir/nonreservoir rock juxtaposition. The present study focuses on the assessment of the sealing potential of the Lower Goru Formation of Badin area, Lower Indus Basin, Pakistan. The uni-directional force is one of the causes of leakage through the upper reservoirs of Lower Goru Formation, i.e. sand A, B and C and thus made a good seal as sand D. The fault properties associated with sealing capacity and leakage are estimated using algorithms. These algorithms are based on the juxtaposition of the reservoir rock against sealing lithology, deformation and present stage of stress regime within the fault plane relative to leakage. Time and depth contour maps of top of the Lower Goru Formation represent a half-graben structure showing uni-directional force in the area. An Allan-type diagram depicted a sand-sand juxtaposition for sand A and juxtaposition of sand A with sand B, thus eliminating any chances of sealing conditions. A similar diagram confirmed shale-sand juxtaposition for sands C and D. The juxtaposition diagram referred to an increase in shale gouge ratio (SGR) values from sand A to sand D with maximum values at sand D, thus classifying good fault sealing potential at sand D. Therefore, it is confirmed that sealing capacity of the fault (F2) increases from sand A (poor seal) where SGR = 0.44% – 0.9% and shale smear factor (SSF) = 0.23 – 1 to sand D (moderate seal) where SGR = 10% – 44% and SSF = 0.05 – 0.22 which means that sand D is more sealed than any other sand in the study area.

Five Year Study of a Unique, Eco-friendly, Menstrual Cup, That Enhances the Quality of Women’s Lives During Menstruation

Menstrual cups are gaining more popularity among women, [1]. who prefer cups over pads and tampons. The innovative FemmyCycle (Figure 2) has several advantages over traditional menstrual cups, which has led to its increased popularity [2]. The objective of this study is to mitigate and correct the possible or potential side effects caused by traditional menstrual cups (Figure 3). The most common side effect among traditional cups is leakage. Despite the fact that 1.9 billion women globally are of menstruating age—spending on average 65 days a year dealing with menstrual blood flow, few good quality studies exist that compare sanitary products, says senior author Penelope Phillips-Howard, a public health epidemiologist from the Liverpool School of Tropical Medicine in the UK. [3]. We focused our study on all causes of leakage and other side effects caused by traditional menstrual cups. Methods of corrective and preventive actions included; the no-spill design, (Figure 4 & Figure 5), use of a removal ring instead of a rigid stem, the use of a flask shaped body rather than the conical shape of traditional menstrual cups, (Figure 2 & Figure 3), the elimination of suction holes and the need to manually open the cup. We analyzed 834 independent reviews by women who have had prior experience with traditional menstrual cups to obtain objective results. The implementation of these design changes and enhancing the written and video instructions produced measurable, objective, positive results in favor of the FemmyCycle. We analyzed all these reviews for FemmyCycle to measure the effects on leakage and other side effects. We selected the reviewers who volunteered to compare the FemmyCycle with their experience with traditional cone shaped menstrual cups. There were many reasons why women preferred FemmyCycle, but the most common by far was the prevention of leakage followed by the ease of insertion, ease of removal and comfort when inserted. The implementation of the design changes from a conical shaped cup with a removal stem to a flask shape cup with a removal ring, in addition to the added no-spill feature and enhanced instructional material, improved the acceptability of the FemmyCycle.

Modeling Transient Leakage Signals from Abandoned Wells with T2Well: Effects of Plug Gap Aperture

Both known and unknown (unmapped) plugged and abandoned wells are potential leakage pathways for CO2 from geologic carbon sequestration (GCS) sites. Although many abandoned wells have cement bridge plugs installed to prevent leakage, the seal between the cement and the inner casing wall is subject to failure creating a leakage flow path for formation fluids and CO2. In this study, we carried out detailed T2Well simulations of non-Darcy flow of CO2 and brine leakage up the gap between cement and inner casing wall and into the open fluid-filled column of a prototypical abandoned well. The goal of our study was to understand the expected leakage behavior dynamics, leakage rates, and the temporal signals associated with leakage that can be targets of near-surface monitoring. Simulation results show that the leakage of CO2 and brine upward in this system is transient with interesting phase interference behavior as buoyant CO2 flowing upward displaces brine as it flows through the cement-casing gap, into the column of brine, and upward to the top of the well. Oscillatory flows with varying pressure, temperature, and flow rates of CO2 and brine show strong dependence on gap aperture. The temporal patterns of leakage may be detectable with surface and near-surface monitoring approaches. In addition to helping with detecting and locating leaking wells, these transient leakage signals may provide information on the cause of leakage that could inform effective remediation design and execution approaches.

Trans-nasal endoscopic repair of cerebrospinal fluid rhinorrhoea: a retrospective analysis

<p class="abstract"><strong>Background:</strong> The purpose of present study was to assess the management and surgical outcomes of trans-nasal endoscopic repair of CSF rhinorrhoea.</p><p class="abstract"><strong>Methods:</strong> A retrospective study was conducted on the basis of medical records of 8 patients (6 males and 2 females) who had undergone trans-nasal endoscopic reconstructive surgery for CSF leak in a tertiary care hospital. Data so collected was analyzed to determine the demographic and diagnostic factors with surgical outcomes. Rate of success achieved was also assessed. </p><p class="abstract"><strong>Results:</strong> Majority of patients were in the age group of 21-40 years with mean age of 28.50 years. Main cause of leak was trauma (75%) and most common site of defect was found to be the cribriform plate of ethmoid bone (75%). 38% patients suffered from recurrent episodes of meningitis. Repair of dehiscence was done by variety of graft material like fat, fascia, middle turbinate mucosa, septal bone, cartilage or mucosa and fibrin glue. Success rate of 100% was observed. No post-surgical complications were encountered in this series.</p><p><strong>Conclusions:</strong> Trans-nasal endoscopic surgical technique is an effective and atraumatic procedure for repair of CSF rhinorrhoea with minimum morbidity and low post-operative complications. </p>

Novel Chitohexaose Compounds to Treat Abdominal Peritonitis Leading to Sepsis

Gastrointestinal perforation and appendicitis are the common cause of leakage of alimentary contents into the peritoneal cavity, leading to sepsis with a mortality rate between 14.7% and 29.9%. Besides its clinical challenge, the treatment of sepsis and its complications impose an enormous economic burden on health care systems worldwide. In sepsis caused by gram-negative bacteria, the bacterial endotoxin, lipopolysaccharide (LPS), activates the immune system through signaling the MD2-toll like receptor 4 complex (TLR4) to initiate the infection process for production of inflammatory cytokines (TNF-α, IL-1β, IL-6) that are responsible for hyperinflammation. Thus, development of antagonists that block these receptors either by inhibition of activation of TLRs or downstream signaling pathways would be beneficial in ameliorating the hyperinflammation if introduced early in the therapy. At AyuVis Research, we have designed a series of dual-acting small molecules (AVR-25, 48) that block TLR4 receptor, which inhibits the production of proinflammatory cytokines; stimulate production of macrophages leading to organ protection; and limit tissue injury. Our lead compound, AVR-25, has efficaciously demonstrated survival, organ protection, downregulation of inflammatory cytokines, and upregulation of M2 biomarkers and cytokines such as arginase-1 and IL-10 in vivo in a cecal ligation and puncture (CLP) sepsis mouse model via intravenous (IV) dosing. Our published and unpublished in silico modeling experiment has demonstrated that our compounds have a unique binding mode where they either bind to the dimerization site or to the middle of the TLR4 protein restricting the dimerization of protein, which is a critical step in downstream signaling. In our CLP model of both young and aged mice, compounds AVR-45 and AVR-48 efficaciously protected them against CLP-induced death and organ dysfunction at a 10-mg/kg (q8h) IV dose. These compounds also possess modest antibacterial activities against both gram-positive and gram-negative bacteria, as well as synergistic/additive activity in combination with standard of care antibiotics such as primaxin (PRM, Imipenem + cilastatin), indicating good potential for adjuvant antimicrobial therapy. We are the first and only key investigator team to observe the effects of AVR-25 and AVR-48 natural oligosaccharide-derived small molecules in preventing sepsis-induced death in the murine CLP-induced peritonitis model. We believe that development of this class of compounds will lead to a paradigm shift and could become a very high-gain project in the treatment management of inflammation and organ dysfunction in intra-abdominal sepsis. These significant research capabilities will open a new facet to combination therapy with antibiotic and standard antihypotensive agents for critically ill patients.

Причины несостоятельности швов анастомозов после гастрэктомии

Цель работы: изучить причины и способы профилактики несостоятельности швов анастомозов после гастрэктомии.
 Материалы и методы. Технические причины несостоятельности швов анастомоза общеизвестны: натяжение тканей [8, 9, 14, 15], плохая адаптация сшиваемых поверхностей [8, 9], прорезывание скобок после извлечения сшивающих аппаратов [12, 15], неумелое применение сшивающих аппаратов и неправильный уход за ними [15, 16], нарушение кровоснабжения на уровне сшиваемых отрезков пищеварительного тракта [1, 8, 9, 16], наложение швов по ходу основного продольного слоя мышц пищевода [16], что приводит к прорезыванию швов, травма поджелудочной железы, в результате чего происходит истечение агрессивного содержимого из поврежденной или резецированной поджелудочной железы [9], что приводит к инфицированию линии швов анастомоза [8, 12], а так же некротическим и воспалительным процессам [17], наложение швов на пораженный участок стенки пищевода, так же часто приводит к несостоятельности пищеводно-кишечного анастомоза [12, 14]. Многочисленными исследованиями доказано, что одной из основных причин несостоятельности швов пищеводно-кишечного анастомоза является лимфодиссекция в объеме D2. Выполнение лимфодиссекции в объеме D2 по сравнению с D1 сопровождалось значительным ростом послеоперационной летальности (10—13 и 4—6,5%), частоты послеоперационных осложнений (43—46 и 25—28%), прежде всего несостоятельности швов анастомозов (в английском исследовании она достигла 26% в группе D2) и абсцессов брюшной полости, частоты повторных операций (18 и 8%), средней длительности пребывания больных в клинике после операции (23—25 и 18 дней); все различия статистически достоверны (р<0,05—0,001). На основании полученных данных авторы сделали заключение, что увеличение объема лимфодиссекции приводит к значимому увеличению числа послеоперационных осложнений и летальности, потому до получения данных об отдаленных результатах резекция D2 не
 должна использоваться при лечении рака желудка, по крайней мере в Европе. [3,4,5]
 
 Результаты и их обсуждения. За период с 1986 по 2005 годы, в Республиканском онкологическом центре выполнено 1477 гастрэктомий по методике Бондаря Г.В. Несмотря на высокую надежность данного анастомоза, несостоятельность швов пищеводно-кишечного анастомоза отмечена у 16 наших больных (1,08±0,27%), и у 2 (0,14±0,1%) несостоятельность культи двенадцатиперстной кишки, оперированных в этот период времени.
 Выводы: применение муфтообразного пищеводно-кишечного анастомоза, формируемого по методике Бондаря Г.В. соответствует современным требованиям хирургии рака желудка, анастомоз надежный и обеспечивает хорошие условия для пищеварения в новых условиях после выполнения гастрэктомии, что соответствует литературным данным.

Quantification of leakage in batch biogas assays

Abstract Avoiding leaks is essential for accurate measurement of biogas production by batch assays. Here we present a simple method for detecting leaks and correcting results, based on the change in bottle mass during incubation. Three experiments were carried out using pure chemicals, wastewater sludge, and other complex substrates to test and demonstrate the method, and leaks were detected in all three. The frequency and magnitude of leakage was related to headspace pressure and the number of times bottle septa had been punctured. Comparison to an independent estimate of leakage in two experiments showed that the proposed method is accurate. This mass-based approach can generally be used to detect leaks as small as 20% of total biogas or methane production, or lower when biogas production is high relative to the precision of mass measurements. Additional research is needed to improve the sensitivity of the method and to better understand the causes of leakage. Given the potential importance of leaks and the simplicity of leakage measurements, we recommend that this method is always used in batch biogas assays.