Active Leakage Research Articles

Elimination of bile leakage in liver injuries

Aim. To study the causes and consequences of bile leakage in liver injury and determine the potential ways for its elimination. Materials and methods. The study involved a retrospective analysis of 204 liver injuries of various types. 26 % of cases were detected with isolated abdominal trauma, 74 % – with concomitant abdominal injury. According to the AAST grading scale, 15.7 % of patients got grade II liver injuries, 44.6 % – grade III, 34.3 % – grade IV, and 5.4 % – grade V. Since concomitant injuries predominated, surgical treatment was initially performed in the overwhelming number of cases. 14 % of cases received non-operative management. Results. The incidence of bile leakage amounted to 28.4 % for all liver injuries and reached 54.9 % for III–V grade injuries (AAST). Small bile leakage prevailed, while active leaking was observed in 36.2 %. Damage to peripheral parts of the biliary tract was noted in most cases (68 %). Conservative management of patients with small bile leakage associated with damage to peripheral parts of the biliary tract appeared successful in 48.5 % of cases. Endoscopic biliary drainage of bile ducts proved effective in case of active bile leakage and (or) injuries of the central bile ducts. Conclusion. Endoscopic biliary drainage of bile ducts is considered the most effective for elimination of active biliary leakage in the absence of biliary peritonitis and communication of biliary tract with pleural cavity.

Optimal trading and competition with information in the price impact model

Information drives trading and hence affects price dynamics. We study how an informed trader optimally trades, how multiple traders compete with each other, and how their competition affects price dynamics as well as their inventories in the linear price impact model framework. We formulate the informed trading problem as a stochastic optimal control problem and a stochastic differential game in different cases. By virtue of different methods, problems are solved explicitly in all cases. In the case of a single trader, the risk-averse informed trader trades less in the beginning and then speeds up to reduce exposure to the volatility of dynamic information. In addition, the risk-averse trader reveals information more slowly and thus contributes less to price efficiency. When multiple risk-neutral traders compete with information, regardless of the competition structure, they tend to trade more rapidly in the early stage to fill orders at a good price. Competition and the presence of a leader help promote price efficiency, and competition also leads to the empirically observed mean-reverting behavior of price dynamics and order flows. Furthermore, among risk-averse informed traders, inventory management triggers predatory trading and active information leakage during informed trading, and the positions of traders with the same level of risk aversion tend to be identical and mean-reverting to zero under multiple rounds of competition.

Response of early diagenesis to methane leakage in the inner shelf of the East China Sea

Shelf seas are experiencing a rise in shallow gas leaks, primarily methane, raising concerns due to their environmental impact. However, the effect of the leaks on early diagenesis remains poorly understood. This study analyzes sediment lithology, organic geochemistry and porewater geochemistry of two short cores collected nearby the pockmarks in the muddy inner shelf of the East China Sea. Our findings clearly demonstrate the impact of methane leakage on early diagenesis, evidenced by the shallower position of the SMTZ (sulfate-methane transition zone), higher concentrations of uranium (U), vanadium (V), and manganese (Mn) in the porewater near and above the SMTZ, and downcore decrease in Mg2+, Ca2+, and Sr2+ concentrations versus increase in Mg2+/Ca2+ and Sr2+/Ca2+ ratios. Their profile variations and the difference between two cores are determined by the intensity of methane leakage. The estimated methane diffusive flux of 619 mmol m-2 yr-1 at YEC7–2 is roughly 8.5 times that at YEC7–1 (73 mmol m-2 yr-1), consistent with a shorter distance of YEC7–2 to the pockmark with active methane leakage. A schematic model is summarized to demonstrate the response of early diagenesis processes to the increasing methane leakages in response to changing sedimentation regimes from accretion to severe erosion. This study undoubtedly improves our understanding mutual promotion effect between seafloor erosion and gas leakage, and their impact on early diagenesis processes and resultant porewater geochemical changes and authigenic mineral records.

Pharmacological inhibition of receptor-interacting protein kinase 2 (RIPK2) elicits neuroprotective effects following experimental ischemic stroke

Ischemic stroke induces a debilitating neurological insult, where inflammatory processes contribute greatly to the expansion and growth of the injury. Receptor-interacting protein kinase 2 (RIPK2) is most well-known for its role as the obligate kinase for NOD1/2 pattern recognition receptor signaling and is implicated in the pathology of various inflammatory conditions. Compared to a sham-operated control, ischemic stroke resulted in a dramatic increase in the active, phosphorylated form of RIPK2, indicating that RIPK2 may be implicated in the response to stroke injury. Here, we assessed the effects of pharmacological inhibition of RIPK2 to improve post-stroke outcomes in mice subjected to experimental ischemic stroke. We found that treatment at the onset of reperfusion with a RIPK2 inhibitor, which inhibits the phosphorylation and activation of RIPK2, resulted in marked improvements in post-stroke behavioral outcomes compared to the vehicle-administered group assessed 24 h after stroke. RIPK2 inhibitor-treated mice exhibited dramatic reductions in infarct volume, concurrent with reduced damage to the blood-brain barrier, as evidenced by reduced levels of active matrix metalloproteinase-9 (MMP-9) and leakage of blood-borne albumin in the ipsilateral cortex. To explore the protective mechanism of RIPK2 inhibition, we next pretreated mice with RIPK2 inhibitor or vehicle and examined transcriptomic alterations occurring in the ischemic brain 6 h after stroke. We observed a dramatic reduction in neuroinflammatory markers in the ipsilateral cortex of the inhibitor-treated group while also attaining a comprehensive view of the vast transcriptomic alterations occurring in the brain with inhibitor treatment through bulk RNA-sequencing of the injured cortex. Overall, we provide significant novel evidence that RIPK2 may represent a viable target for post-stroke pharmacotherapy and potentially other neuroinflammatory conditions.

Pathogenesis of Central Serous Chorioretinopathy and the Link Between Choroidal Hyperpermeability and Retinal Pigment Epithelium Pump Reversal

Purpose: To describe 6 cases of acute central serous chorioretinopathy (CSCR) and the response to laser treatment, focusing on the underlying pathogenic mechanism. Methods: Multimodal imaging from 6 eyes of 6 patients with acute and recurrent CSCR were reviewed including fundus autofluorescence (FAF), fluorescein angiography (FA), indocyanine green angiography (ICGA) and optical coherence tomography (OCT) at baseline and after laser therapy. Results: In 3 out of the 6 cases with acute CSCR, the hyporeflective lucency sign was identified with cross sectional and en face OCT and co-localized with an intense active inkblot retinal pigment epithelium (RPE) leak on FA. The development of this sign was suggestive of active leakage into the subretinal space displacing overlying subretinal hyperreflective material (SHRM) and suggestive of a reversal of RPE pump function. All six cases were treated with focal laser to directly target the intense leakage points with remarkable resolution of the fluid due to destruction of the RPE cells mediating reversal of pump function. Conclusions: Unlike chronic CSCR in which degenerative changes of the RPE lead to oozing of fluid into the subretinal space, in acute forms of CSCR including bullous CSCR, there are focal leaks of the RPE that actively drive fluid into the subretinal space suggestive of RPE pump reversal. We propose that pachychoroid disease causes increased hydrostatic pressure and increased resistance to the RPE pump thereby triggering a reversal in pump function. Understanding this concept can have therapeutic implications.

Occult retinal neovascularization following intravitreal bevacizumab and laser treatment for retinopathy of prematurity

BackgroundWe present a patient with retinopathy of prematurity (ROP) who developed worsening plus disease after complete regression of stage 3 ROP. The use of fundus fluorescein angiography (FFA) aided the visualization of occult neovascularization that caused the disease progression.Case presentationThe patient was at high risk for ROP due to low birth weight of 690 g and gestational age of 25 weeks. After the diagnosis of stage 3 ROP in zone I without plus disease, she was treated initially with bilateral intravitreal bevacizumab (IVB) and followed by laser photocoagulation 5 weeks later. Despite the resolution of ROP stage, the plus disease worsened. Neither systemic risk factors nor skip laser areas were observed. Hence, FFA was performed and subsequently identified occult neovascularization with active leakage. Additional IVB and laser treatment in the capillary dropout area inside vascularized retina were added. The plus disease improved but mild arteriolar tortuosity persisted.ConclusionsWorsening of plus disease after completion of laser ablation and IVB with complete regression of stage 3 ROP is rare. Systemic risk factors such as continuous oxygen therapy and cardiovascular disease should be ruled out. FFA aided in identifying occult neovascularization and prompted further treatment.

Interventional treatment of refractory non-traumatic chylous effusions in patients with lymphoproliferative disorders

To report results of interventional treatment of refractory non-traumatic abdomino-thoracic chylous effusions in patients with lymphoproliferative disorders. 17 patients (10 male; mean age 66.7 years) with lymphoproliferative disorders suffered from non-traumatic chylous effusions (chylothorax n = 11, chylous ascites n = 3, combined abdomino-thoracic effusion n = 3) refractory to chemotherapy and conservative therapy. All underwent x-ray lymphangiography with iodized-oil to evaluate for and at the same time treat lymphatic abnormalities (leakage, chylo-lymphatic reflux with/without obstruction of central drainage). In patients with identifiable active leakage additional lymph-vessel embolization was performed. Resolution of effusions was deemed as clinical success. Lymphangiography showed reflux in 8/17 (47%), leakage in 2/17 (11.8%), combined leakage and reflux in 3/17 (17.6%), lymphatic obstruction in 2/17 (11.8%) and normal findings in 2/17 cases (11.8%). 12/17 patients (70.6%) were treated by lymphangiography alone; 5/17 (29.4%) with leakage received additional embolization (all technically successful). Effusions resolved in 15/17 cases (88.2%); 10/12 (83.3%) resolved after lymphangiography alone and in 5/5 patients (100%) after embolization. Time-to-resolution of leakage was significantly shorter after embolization (within one day in all cases) than lymphangiography (median 9 [range 4–30] days; p = 0.001). There was no recurrence of symptoms or post-interventional complications during follow-up (median 445 [40–1555] days). Interventional-radiological treatment of refractory, non-traumatic lymphoma-induced chylous effusions is safe and effective. Lymphangiography identifies lymphatic abnormalities in the majority of patients and leads to resolution of effusions in > 80% of cases. Active leakage is found in only a third of patients and can be managed by additional embolization.

Bilateral uveitis, retinal periphlebitis, and optic neuritis associated with non-pineal central nervous system germinoma

Purpose: To report a case of bilateral uveitis, retinal periphlebitis, and optic neuritis associated with a non-pineal central nervous system (CNS) germinoma. Methods: Case report. Results: A 32-year-old male presented with episodes of acute painless visual disturbance in each eye, and was found to have decreased visual acuity, abnormal color vision, an afferent pupillary defect in the left eye, bilateral optic disc edema, perivenous sheathing, and candle-wax dripping exudates. Optical coherence tomography revealed bilateral intraretinal fluid and posterior vitreous hyperreflective opacities. Fluorescein angiography revealed bilateral optic disc leakage without active small vessel leakage. Magnetic resonance imaging of the brain and orbits revealed enhancing periventricular lesions and enhancement of the left optic nerve and bilateral perioptic nerve sheaths, posterior globes, and optic nerve heads. Brain biopsy was consistent with a CNS germinoma. His ocular signs and symptoms improved with chemotherapy for the germinoma. Conclusion: CNS germinomas, including those located outside the pineal region, can be associated with optic neuritis, uveitis, and periphlebitis including characteristic candle-wax dripping exudates. Ocular signs and symptoms typically improve with treatment of the underlying germinoma.

Evaluation of Non-revenue Water Management: A Case Study of Lodwar Water Supply in Lodwar Municipality, Kenya

This paper scrutinises the availability and effectiveness of non-revenue water management practices at Lodwar Water Supply, which serves an urban populace in Arid, Northern Kenya. The case study is representative of medium-sized water utilities serving populations in water-scarce areas within developing countries. Challenges encountered by water utilities in developing countries are unique, and their resolution requires context-specific approaches. For instance, Lodwar water supply posted an estimated 52% non-revenue water in a recent assessment by Kenya’s water services regulatory agency (WaSREB). The utility lost half of its production. This is unacceptable for a water utility serving an arid service area with 43% water coverage. This paper documents the findings of a causal study conducted to identify probable reasons for the water utility performance and develop recommendations to reverse the worsening non-revenue water trend. Four aspects were identified for scrutiny at the water utility; these were: Availability of strategies, methods, and policies for non-revenue water reduction; Employee and Consumer awareness of non-revenue water management; Techniques for enumeration of components of non-revenue water and the nexus between the foregoing and the prevailing poor non-revenue water and overall performance of the water utility. Three hundred eighty-five questionnaires were administered to consumers, randomly sampled across the selected study area. This was followed by a non-quantitative audit of non-revenue water practices by the water utility and focused group discussions with top management and technical staff at the water utility. This study established the absence of deliberate strategies for control of non-revenue water by the water utility as the critical reason for the unacceptably poor non-revenue water and overall performance of Lodwar Water Supply. Recommendations for mitigation of non-revenue water included the establishment of zone-specific, updated consumer database; DMAs with functional inflow meters; acquisition of meter testing and calibration system; institution of active leakage control initiatives and personnel capacity development

Water Distribution System Management in District Metered Area (DMA) Kalipuro 5

Water supply system is an important infrastructure that needs improvement in water distribution networks efficiency, along with energy consumption and water losses. DMA Kalipuro 5 is formed to improve the management of water distribution system by monitoring the water flows into the district. This program is supported by pressure management, repairs, active leakage control, and asset management. Water balance is the first step to reduce the water losses. From the water balance of DMA Kalipuro 5 calculated in January and September 2022, the percentage of water losses decreases 7,02%, from 62,55% to 55,53%. The percentage of physical water losses also decreases 7,06%, from 62,32% to 55,26%. Pressure management is conducted in order to reduce the physical water losses by installing pressure reducing valve (PRV). From the simulation of existing water distribution network, installing PRV can reduce the highest pressure from 108,82 meters to 58,42 meters.

Hepatobiliary-specific magnetic resonance contrast agents: role in biliary trauma.

Non-iatrogenic traumatic bile duct injuries (NI-TBIs) are a rare complication after abdominal trauma, with an estimated prevalence of 2.8-7.4% in patients underwent blunt liver injuries. They may be overlooked in patients with extensive multi-organ trauma, particularly hepatic, splenic and duodenal injuries, which have a prevalence of 91%, 54% and 54%, respectively. Whole body contrast-enhanced computed tomography (CE-CT) represents the examination of choice in polytraumatized hemodynamically stable patients, as it allows a comprehensive evaluation of vascular, parenchymal, bone and soft tissues injuries, but the diagnosis of any biliary leaks is limited to the evaluation of nonspecific imaging findings and on findings evolution in the follow-up, such as the progressive growth of fluid collections. Furthermore, biliary complications, such as the occurrence of biloma or biliary peritonitis, may become manifest several days after the initial trauma, often with unspecific progressive signs and symptoms. Although CT and ultrasonography can suggest bile leaks based on several nonspecific imaging findings (e.g., fluid collections), magnetic resonance imaging (MRI) using hepatobiliary contrast agents helps to identify the site and entity of post-traumatic biliary disruption. Indeed, MRI allows to obtain cholangiographic sequences that may show post-traumatic active bile leakage and cysto-biliary communications by direct visualisation of contrast material extravasation into fluid collections, increasing the preoperative accuracy of NI-TBIs. Few data are available about MRI use in the follow-up of trauma with NI-TBI management. So, in the present mini review, its role is reviewed and our preliminary experience in this field is reported.

Serous Maculopathy Due to Aspecific Choroidopathy (SMACH).

Serous Maculopathy Due to Aspecific Choroidopathy (SMACH).

A soft-switched flyback converter with leakage recovery snubber for class 2 LED driver

This work presents a soft-switching flyback converter with active leakage recovery snubber suitable for use in high-performance class 2 LED lamp drivers. The proposed converter enjoys the features of simple circuit structure, improved switching performance, high efficiency and high power density. Transformer leakage energy of the flyback converter is recovered using an active auxiliary circuit, which also helps in soft-switching transition of the switches and power diodes. Switching turn-on and turn-off of its main switch occurs under ZVZCS and ZVS conditions respectively, whereas ZCS turn-on and ZVZCS turn-off of the auxiliary switch are also achieved in this converter. The detailed steady-state operating principle with mathematical equations, design guidelines and loss analysis are presented in this work. Finally, the converter feasibility is thoroughly tested through laboratory experimentation on a hardware prototype. The experimental results have successfully validated the theoretical analysis and real-time behavior of the converter.

İçme Suyu Şebekelerinde Kayıp Kaçak Seviyesinin Belirlenmesi: Merzifon İlçesi Örneği

Bu çalışmada içme suyu şebekelerinde meydana gelen fiziki su kayıplarının su kaynağının korunmasında önemli hususlardan biri olduğu gözler önüne serilmiştir. İçme suyu talebi nüfus artışıyla birlikte her geçen gün artmaktadır. Buna karşın içilebilir su miktarı azalmakta ve içme suyu şebekelerinde suyun etkin kullanımı önemli hale gelmektedir. Su şebekesine verilen ancak kullanıcılara ulaşmayan su kayıp kaçak olarak bilinmektedir. Kayıp kaçaklar fiziki ve görünür kayıplar olarak adlandırılmaktadır. Araştırmada su kayıp kaçak seviyesinin belirlenmesi için 2020 yılına ait sisteme verilen su miktarları, boru arıza sayıları, kullanım alanlarına göre su tüketim miktarları, minimum gece debi bilgileri belediyeden temin edilmiştir. Merzifon örneğinde su kayıp kaçak seviyesinin tespiti için su dengesi oluşturularak, altyapı sızıntı indeksi tespit edilmiştir. Merzifon örneğinde 2020 yılına ait fiziki su kayıp miktarının % 44.12 olduğu tespit edilmiştir. Altyapı sızıntı indeksi (ILI) 13.6 olarak tespit edilmiştir. Su kaynağının korunması için içme suyu şebekesindeki basınç yönetimi, şebeke yenileme, aktif sızıntı kontrolü, onarım hız ve kalitesinin iyileştirilmesi çalışmaları yapılmalıdır.

High-Resolution Computed Tomography as an Initial Diagnostic and Localization Tool in Patients with Cerebrospinal Fluid Rhinorrhea: A Meta-Analysis

Background and Objectives: This study was performed to investigate the utility of high-resolution computed tomography (HRCT) for the initial localization of cerebrospinal fluid rhinorrhea. Methods: HRCT data regarding the point of cerebrospinal fluid leakage (as confirmed in the operating room), collected up to December 2022, were extracted from five databases. The risk of bias of the included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Results: The search revealed eight relevant studies with a total of 254 patients. The diagnostic odds ratio of the imaging studies was 10.0729 (95% confidence interval [CI]: 2.4486; 41.4376; I2 = 54.1%). The area under the summary receiver operating characteristic curve was 0.8. Sensitivity, specificity, the negative predictive value, and the positive predictive value were 0.7550 (95% CI: 0.6163; 0.8553; I2 = 69.8%), 0.8502 (95% CI: 0.5986; 0.9557, I2 = 49.3%), 0.4106 (95% CI: 0.2418; 0.6035; I2 = 59.0%), and 0.9575 (95% CI: 0.8955; 0.9834; I2 = 27.7%), respectively. Conclusions: HRCT can be used to accurately localize cerebrospinal fluid rhinorrhea because it shows bony defects in high detail. However, it has limited utility for the evaluation of active leakage, and localization is difficult in the presence of coexisting lesions.

The Impact Assessment of Water Supply DMA Formation on the Monitoring System Sensitivity

One of the main tasks that water companies face is limiting water losses through the distribution network. This issue is becoming more and more relevant because of progressive climate changes and rising water resource deficiencies. The first step to reducing water losses is the proper detection of leakages, including their location and size. A common approach, called active leakage control, is to divide the water network into District Metered Areas (DMAs) to detect unreported leaks in the water distribution system (WDS). The operating flow meter device at the border of the DMA allows the determination of the number of water losses by balancing water inflows into the zone and billed water consumption. However, to precisely locate a water leak it is necessary to equip the DMA with an adequate number of pressure sensors. The aim of this paper is to evaluate the impact of water supply DMA formation on the sensitivity of the monitoring system in accordance with the number and location of the pressure sensors and the geometric structure of the water pipes in the DMA in order to successfully detect water leakage. The research was conducted on a model grid network with a constant node number but a differential pipe structure. Subsequently, results were verified in the conditions of a real water supply network. The obtained tests showed no clear relationship between the effectiveness of leak detection and the network complexity but confirmed a significant improvement in leak detection after equipping the monitoring system with an additional pressure gauge.

Efficacy and Safety of Laser Photocoagulation in Persistent Idiopathic Central Serous Chorioretinopathy: A Prospective Interventional Study

Introduction: Central Serous Chorioretinopathy (CSCR) encompasses the macular area, secondary to the accumulation of subretinal fluid and increased permeability from the choriocapillaris resulting in focal or diffuse dysfunction of the retinal pigment epithelium. Diagnosis of CSCR is done by several procedures like clinical examination, Amsler grid testing, fluorescein angiography, ocular coherence tomography. There are several treatment options including photodynamic therapy, laser photocoagulation, etc., for CSCR. Aim: To study the efficacy and safety of laser photocoagulation in persistent idiopathic CSCR. Materials and Methods: The present prospective interventional study was conducted in the Department of Ophthalmology, BJ Government Medical College and Sassoon General Hospital, Pune, Maharashtra, India, from August 2019 to January 2021. A total of 30 patients (30 eyes) with idiopathic CSCR, persistent for duration of three months or more with worsening of visual symptoms, active leakage on Fundus Fluoresceine Angiography (FFA) were subjected to 532 nm subthreshold green laser photocoagulation treatment after routine investigations. Statistical analysis was done on International Business Machines (IBM) Statistical Package for the Social Sciences (SPSS) software version 20.0. Results: In the present study, there was male preponderance (86.7%) for the CSCR cases. The mean±Standard Deviation (SD) age of in the study was 37.7±0.07 years. All the eyes studied had unilateral involvement with 53.35% right eye involvement and 46.7% left eye involvement. The duration of current episode of CSCR in months showed a mean+SD of 5.86±1.40. The distribution of visual acuity in affected eye (before laser treatment) depicts the mean prelaser Best Corrected Visual Acuity (BCVA) of 30 patients at baseline was (0.68±0.20) in LogMAR. About 67% patients experienced central scotoma and 33% patients had metamorphopsia on Amsler chart. Distribution of active leakage site on FFA showed that 43% cases had active leakage in superonasal quadrant, 30% had active leakage in superotemporal, 17% had active leak in inferonasal quadrant and 10% had active leak in inferotemporal quadrant. CSCR associated with or without Retinal Pigment Epithelium (RPE) atrophy showed that 63.3% patients had RPE atrophy suggesting long-standing course of disease with NSD and subretinal fluid collection affecting RPE. Prelaser mean CMT on OCT of affected eye was 445.83±54.79 µm which was reduced to mean CMT of 303.57±48.49 µm at four weeks follow up, which further reduced to mean CMT of 224.9±20 µm at end of 12 weeks was statistically significant with p-value<0.001. The statistical analysis for the macular thickness at four weeks and 12 weeks showed significant probability with paired t-test with p-value<0.001. Conclusion: It can be concluded from the present study that early treatment with laser photocoagulation is efficient in the restoration of vision within a period of 12 weeks.

Comparative Analysis on the DMA Partitioning Methods Whether Trunk Mains Participated

In recent years, the District Metered Area (DMA) of water distribution networks (WDNs) has become a major development trend in the water leakage control area. It has significant value in the active leakage control and pressure management of WDNs. This study comments on two DMA partitioning methods (Scheme A and B, previously introduced in another paper) and compares three aspects of their respective performances to elucidate their respective strengths and weaknesses. Scheme A partitions all the network nodes, whereas Scheme B only partitions the remaining network nodes, except the trunk mains. Whether the trunk mains participated in the partitioning process is the key distinction between the two approaches. There is little relevant research that compares and analyzes the effects of the above two methods. This paper applies these two types of partitioning methods to a case network. The respective performances in three aspects, namely economy, water quality, and leakage control, were evaluated and compared. For economy, Scheme A is more economical than Scheme B, saving about 15.34%. For water quality, Scheme B is the best partitioning method because it reduces water age better than Scheme A does. For leakage control, Scheme B has a drop of 19.46%, which is better than Scheme A (a decline of 15.12%) in comparison to the initial leakage.

A case study on integrated management of water losses in Antalya, Turkey

Abstract In this study, effects of the combination of meter replacement and active leakage control on real and apparent losses are investigated. Generally, water meter replacement campaigns, SCADA system operation, data analysis studies and physical leak detection activities are carried out by different units in water utilities. Within the scope of this study, the studies carried out by different units of the water utility were carried out in an integrated manner in the same period and the obtained data sets were analysed together. Thus, water losses, which were at the level of 52% in the pilot study area (PSA), were reduced to 35%. When the volumes of water supplied to the system before and after the study are compared, the volumes after the study were decreased. Also, water losses in the PSA have been reduced by 17%.

İÇME SUYU DAĞITIM SİSTEMLERİNDE ÖNLENEBİLECEK EN UYGUN SIZINTI HACMİNİN VE ORANININ BELİRLENMESİ

İçme suyu dağıtım sistemlerinde meydana gelen arızalar sonucunda yıllık olarak önemli miktarda su kaybolmaktadır. Bu sızıntıların azaltılması ve yönetilmesi için çeşitli yöntemler uygulanmaktadır. Bu çalışmada dağıtım sistemlerinde sızıntıların azaltılması için uygulanan temel yöntemler dikkate alınarak en uygun önlenebilir sızıntı hacminin belirlenmesi amaçlanmıştır. Bunun için aktif sızıntı kontrolü, basınç yönetimi, şebeke rehabilitasyonu ve ekip yönetimi gibi temel yöntemler göz önünde bulundurulmuştur. Bu yöntemler için maliyetler ve potansiyel faydalar belirlenmiştir. Bu fayda maliyetler kullanılarak optimizasyon tabanlı bir model geliştirilmiştir. Geliştirilen model pilot izole bölgede uygulanmıştır. İzole bölgeden alınan veriler dikkate alınarak optimizasyon algoritması ile her bir yöntem için önlenebilir sızıntı hacimleri analiz edilmiştir. Bölgede başlangıçta toplam kayıp miktarı 3,68 l/s (%36,01) olarak hesaplanmıştır. Optimizasyon modeline göre bölgede en uygun kayıp miktarı 1,36 l/s (%13,27) olarak belirlemiştir. Buna göre bölgede ekonomik olarak azaltılabilecek toplam kayıp miktarı 2,32 l/s olarak tespit edilmiştir. En fazla fayda 1,53 l/s ile basınç yönetiminden elde edilmektedir. Analiz sonuçlarına göre uygulanması gereken yöntemler ve bu yöntemlerden elde edilecek faydalar sıralanmıştır. Elde edilen sonuçların özellikle sahada teknik personel için önemli katkılar sunacağı düşünülmektedir.