scholarly journals Gas bubble disease in Nile Tilapia and Hybrid Red Tilapia (Cichlidae, Oreochromis spp.) under culture conditions

2019 ◽  
Vol 36 (3) ◽  
pp. 285-291
Author(s):  
Sema Midilli ◽  
Deniz Çoban ◽  
Mehmet Güler ◽  
Semra Küçük
Keyword(s):  
Nile Tilapia ◽  
Gas Bubbles ◽  
Fish Farming ◽  
Culture Conditions ◽  
Clinical Findings ◽  
Gas Bubble ◽  
Histological Findings ◽  
Red Tilapia ◽  
Special Cases ◽  
Gas Bubble Disease

The supersaturated gases in water can cause gas bubble disease in fish and this can result in death. At the present study a case of gas bubble disease resulted from the gas supersaturation were investigated in Nile tilapia (Oreochromis niloticus) and hybrid red tilapia (Oreochromis sp.). Macroscopic and histological findings were obtained from the culture conditions to find more knowledge on this disease which is frequently seen in fish farming. Study was conducted as two steps in summer (August) and winter (December) months with experimentally cultured fish. According to clinical and histological examinations gas bubbles were found in the dorsal, pectoral and caudal fin, and petechial bleeding were found on pectoral, dorsal, caudal fins and the gill cover. The necropsy were revealed that the stomach and intestines were filled with gas bubbles and the gills were hemorrhagic. According to the histological findings hyperplasia and edema in the gills and hemorrhage in the liver and spleen were found, and gastrointestinal mucosa destruction was observed. The clinical findings were similar for both fishes except for a few special cases and it was observed that the effects of supersaturation were severe for both fish species.

Gas bubble induced scalings in geothermal systems

2021 ◽  
Author(s):  
Lilly Zacherl ◽  
Thomas Baumann
Keyword(s):  
Ph Value ◽  
Saturation Index ◽  
Gas Bubbles ◽  
Gas Bubble ◽  
Geothermal Systems ◽  
Injection Wells ◽  
Term Operation ◽  
Maintenance Schedule ◽  
Local Experience ◽  
Maintenance Schedules

<p>Scalings in geothermal systems are affecting the efficiency and safety of geothermal systems. An operate-until-fail maintenance scheme might seem appropriate for subsurface installations where the replacement of pumps and production pipes is costly and regular maintenance comprises a complete overhaul of the installations. The situation is different for surface level installations and injection wells. Here, monitoring of the thickness of precipitates is the key to optimized maintenance schedules and long-term operation.</p><p>A questionnaire revealed that operators of geothermal facilities start with a standardized maintenance schedule which is adjusted based on local experience. Sensor networks, numerical modelling and predictive maintenance are not yet applied. In this project we are aiming to close this gap with the development of a non-invasive sensor system coupled to innovative data acquisition and evaluation and an expert system to quantitatively predict the development of precipitations in geothermal systems and open cooling towers.</p><p>Previous investigations of scalings in the lower part of production pipes of a geothermal facility suggest that the disruption of the carbonate equilibrium is triggered by the formation of gas bubbles in the pump and subsequent stripping of CO<sub>2</sub>. Although small in it's overall effect on pH-value and saturation index, significant amounts of precipitates are forming at high volumetric flow rates. To assess the kinetics of gas bubble induced precipitations laboratory experiments were run. The experiment addresses precipitations at surfaces and at the gas bubbles themselves.</p>

scholarly journals Analysis of the grade of esophagitis, chromendoscopical and histological findings of esophagus in patients with gastroesophageal reflux disease before and after the therapy

2010 ◽  
Vol 67 (12) ◽  
pp. 991-997
Author(s):  
Vesna Brzacki ◽  
Aleksandar Nagorni ◽  
Dragan Mihailovic ◽  
Suzana Raicevic-Sibinovic ◽  
Bojan Mladenovic
Keyword(s):  
Helicobacter Pylori ◽  
Gastroesophageal Reflux ◽  
Basal Cell ◽  
Reflux Disease ◽  
Eradication Therapy ◽  
Clinical Findings ◽  
Histological Findings ◽  
Cell Hyperplasia ◽  
Basal Cell Hyperplasia ◽  
Before And After

Background/Aim. The symptoms of gastroesophageal reflux desease (GERD) are among the most common complaints for which patients are indicated for visiting gastroenterologist. It occurs as a result of the effect made by gastric reflux contents that moves into the esophagus. The prevalence of all forms of GERD is 40%. The aim of this study was to analyze the grade of esophagitis, chromendoscopical and histological findings of esophagus in patients with GERD before and after the therapy. Methods. A prospective study included 90 patients with symptoms of GERD, divided into 2 groups depending on whether they had endoscopic signs of gastroezophageal reflux (group ERD), or not (group NERD). All the patients had esophagogastroduodenoscopy, chromoendoscopy staining, test for Helicobacter pylori and histological findings of the esophagus. In the patients with Helicobacter pylori infection eradication therapy was done. Results. Esophagitis-B level was present in most of the patients. Among the groups, roughly the same number responded to positive findings on chromoendoscopy. After the therapy, chromoendoscopy was significantly negative in both groups of the patients comparing to chromoendoscopy before the therapy (p = 0.00001). Multiplication and elongation of papilla, basal cell hyperplasia, vascular dilatation, increasing of mitotic activity and the presence of polymorphonuclear leukocyte cells were statistically more frequent histological findings in the group ERB compared to the group NERB. After the therapy, the patients in both groups had statistically less histological findings of appropriate esophageal parameters. Conclusion. Chromoendoscopy combined with the standard endoscopy increases the sensitivity and specificity for reflux disease. Histology in the reflux disease is associated with endoscopic and clinical findings so that the localization of taking biopsies and histological criteria of pathohistological changes must be clearly defined. Multiplication and elongation of papilla, basal cell hyperplasia and the presence of polymorphonuclear leukocytes are the most relevant criteria in the diagnosis NERD.

Nuclei and Cavitation

1970 ◽  
Vol 92 (4) ◽  
pp. 681-688 ◽  
Author(s):  
J. William Holl
Keyword(s):  
Bubble Growth ◽  
Scale Effects ◽  
Gas Bubbles ◽  
Gas Content ◽  
Gas Bubble ◽  
Cavitation Nuclei ◽  
The Stability

This paper is a review of existing knowledge on cavitation nuclei. The lack of significant tensions in ordinary liquids is due to so-called weak spots or cavitation nuclei. The various forms which have been proposed for nuclei are gas bubbles, gas in a crevice, gas bubble with organic skin, and a hydrophobic solid. The stability argument leading to the postulation of the Harvey model is reviewed. Aspects of bubble growth are considered and it is shown that bubbles having different initial sizes will undergo vaporous cavitation at different liquid tensions. The three modes of growth, namely vaporous, pseudo, and gaseous are presented and implications concerning the interpretation of data are considered. The question of the source of nuclei and implications concerning scale effects are made. The measurement of nuclei is considered together with experiments on the effect of gas content on incipient cavitation.

Behavior of Inert Gas Bubbles in Forced Convective Liquid Metal Circuits

1976 ◽  
Vol 98 (1) ◽  
pp. 5-11 ◽  
Author(s):  
W. J. Minkowycz ◽  
D. M. France ◽  
R. M. Singer
Keyword(s):  
Liquid Metal ◽  
Bubble Dynamics ◽  
Bubble Radius ◽  
Gas Bubbles ◽  
Inert Gas ◽  
Liquid Sodium ◽  
Gas Bubble ◽  
Flowing Liquid ◽  
Argon Gas ◽  
The Core

Conservation equations are derived for the motion of a small inert gas bubble in a large flowing liquid-gas solution subjected to large thermal gradients. Terms which are of the second order of magnitude under less severe and steady-state conditions are retained, thus resulting in an expanded form of the Rayleigh equation. The bubble dynamics is a function of opposing mechanisms tending to increase or decrease bubble volume while being transported with the solution. Diffusion of inert gas between the bubble and the solution is one of the most important of these mechanisms included in the analysis. The analytical model is applied to an argon gas bubble flowing in a weak solution of argon gas in liquid sodium. Calculations are performed for these fluids under conditions typical of normal and abnormal operation of a liquid metal fast breeder reactor (LMFBR) core and the resulting bubble radius, internal gas pressure, and mass of inert gas are presented in each case. An important result obtained indicates that inert gas bubbles reaching the core inlet of an LMFBR will always grow as they traverse the core under normal and extreme abnormal conditions and that the rate of growth is quite small in all cases.

scholarly journals Efficiency of aquatic macrophytes to treat Nile tilapia pond effluents

2006 ◽  
Vol 63 (5) ◽  
pp. 433-438 ◽  
Author(s):  
Gustavo Gonzaga Henry-Silva ◽  
Antonio Fernando Monteiro Camargo
Keyword(s):  
Total Nitrogen ◽  
Total Phosphorus ◽  
Nile Tilapia ◽  
Aquatic Macrophytes ◽  
Fish Farming ◽  
Pistia Stratiotes ◽  
Fish Pond ◽  
Nitrogen And Phosphorus ◽  
Dissolved Phosphorus ◽  
Dissolved Nitrogen

The effluents from fish farming can increase the quantity of suspended solids and promote the enrichment of nitrogen and phosphorus in aquatic ecosystems. In this context, the aim of this work was to evaluate the efficiency of three species of floating aquatic macrophytes (Eichhornia crassipes, Pistia stratiotes and Salvinia molesta) to treat effluents from Nile tilapia culture ponds. The effluent originated from a 1,000-m² pond stocked with 2,000 male Nile tilapia Oreochromis niloticus. The treatment systems consisted of 12 experimental tanks, three tanks for each macrophyte species, and three control tanks (without plants). Water samples were collected from the: (i) fish pond source water, (ii) effluent from fish pond and (iii) effluents from the treatment tanks. The following water variables were evaluated: turbidity, total and dissolved nitrogen, ammoniacal-N, nitrate-N, nitrite-N, total phosphorus and dissolved phosphorus. E. crassipes and P. stratiotes were more efficient in total phosphorus removal (82.0% and 83.3%, respectively) and total nitrogen removal (46.1% and 43.9%, respectively) than the S. molesta (72.1% total phosphorus and 42.7% total nitrogen) and the control (50.3% total phosphorus and 22.8% total nitrogen), indicating that the treated effluents may be reused in the aquaculture activity.

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