Analysis Of Scale Samples Research Articles

Mechanism of Salt Precipitation Blockage in Low-Producing Gas Wells and the Method of Acidification Blockage Removal.

In the Changqing area, over 23.6% of gas wells produce less than 0.1 × 104 m3/d of gas daily, posing a challenge to gas field sustainability. Laboratory analysis of scale samples from three wells and formation water analysis via inductively coupled plasma revealed soluble salt as the primary well blockage, with sodium chloride and calcium chloride comprising 48.0-81.2% of total content. The G3# well blockage contains a small amount of quartz from acid-insoluble components of carbonate acidification. Formation water from all wells exhibited high salinity (up to 153 g/L) with a calcium chloride water type. Scanning electron microscopy and EDS confirmed halite and quartz features in blockage samples. Theoretical calculations show salt crystallization when tubing pressure falls below 10 MPa and daily water production is <1.0 tons/day. Lower production leads to lower tubing pressure and higher salt precipitation at the bottom of the well. For G1# and G2# blockages, HCl dissolves >90%, and water >85%, making them suitable removal agents. For 3# blockage, mud acid with >80% dissolution is recommended. Chemical methods effectively clean the wellbore and formation. Optimized blockage removal measures increase tubing pressure and daily production by 2.18 and 4.05 times, respectively. This study offers insights into addressing well blockage challenges in low-producing gas wells.

Optimization and Field Test of a Chelating Acid System for Scaled Gas Wells in the Hechuan Gas Field

The Hechuan gas field is one of the tight gas reservoirs with the highest formation water salinity in China. The content of metal ions, such as calcium, magnesium, iron, and barium, is as high as 20 g/L. Severe scales in near-wellbore reservoir blocks the gas and liquid flow paths, affecting the normal production of gas wells. The analysis of scale samples shows that the scale compositions in the Hechuan gas field are complex, which are composed of calcium carbonate, calcium sulfate, barium sulfate, iron salt, silicate, and other inorganic scales. To dissolve these scales, 14 kinds of laboratory self-made chelating acids named AST-01 to AST-14, sequentially, were evaluated by the descaling rate, in which the chelating acid AST-01 was selected with a dissolution rate of 77.7%. Meanwhile, the optimal concentration and reaction time of AST-01 were investigated, and the concentrations of the corrosion inhibitor, the iron ion stabilizer, and surfactants were also optimized. Then, a chelating acid descaling formula was obtained, which was 15~20% of AST-01 chelating acid + 1.5~2.0% of corrosion inhibitor + 2.5% of iron ion stabilizer + 0.3% of drainage aid. A pilot field trial of this descaling formula was applied in a Hechuan X1 well. A remarkable result was obtained in that the shut-in tubing pressure recovery rate was increased by 14 times, the gas production was increased by 10 times, and the gas well resumed to produce continuously again.

Long-term mark-recapture and growth data for large-sized migratory brown trout (Salmo trutta) from Lake Mjøsa, Norway.

BackgroundLong-term data from marked animals provide a wealth of opportunities for studies with high relevance to both basic ecological understanding and successful management in a changing world. The key strength of such data is that they allow us to quantify individual variation in vital rates (e.g. survival, growth, reproduction) and then link it mechanistically to dynamics at the population level. However, maintaining the collection of individual-based data over long time periods comes with large logistic efforts and costs and studies spanning over decades are therefore rare. This is the case particularly for migratory aquatic species, many of which are in decline despite their high ecological, cultural and economical value.New informationThis paper describes two unique publicly available time series of individual-based data originating from a 51-year mark-recapture study of a land-locked population of large-sized migratory brown trout (Salmo trutta) in Norway: the Hunder trout. In the period 1966-2015, nearly 14,000 adult Hunder trout have been captured and individually marked during their spawning migration from Lake Mjøsa to the river Gubrandsdalslågen. Almost a third of those individuals were later recaptured alive during a later spawning run and/or captured by fishermen and reported dead or alive. This has resulted in the first data series: a mark-recapture-recovery dataset spanning half a century and more than 18,000 capture records. The second data series consists of additional data on juvenile and adult growth and life-history schedules from half of the marked individuals, obtained by means of scale-sample analysis. The two datasets offer a rare long-term perspective on individuals and population dynamics and provide unique opportunities to gain insights into questions surrounding management, conservation and restoration of migratory salmonid populations and freshwater ecosystems.

High performance liquid chromatography – Mass spectrometric bioanalytical method for the determination of dapoxetine in human plasma: Application for bioequivalence study

Dapoxetine is an oral medication used for treatment of premature ejaculation (PE) in men aged (18–64 years). In this study, we present a validated, precise and sensitive method for determination of dapoxetine in human plasma by liquid chromatography/ electrospray ionization-tandem mass spectrometry. Dapoxetine and the internal standard (Dapoxetine- d6) were extracted from plasma via liquid–liquid extraction (LLE). The LC separation was performed utilizing ACE C8 (4.6 X50) mm, 5 µm column. The mobile phase was composed of acetonitrile and buffer (0.01 M Ammonium acetate +0.02% Formic acid solution) (85:15, v/v). The method was linear within the concentration range of 5.0–600 ng/mL for Dapoxetine in human plasma. Short analytical run was achieved with 1.6 min run time. Intra-day and inter-day accuracy was between 97 and 106% with precision (CV, %) of ≤ 5% achieved across all the quality control samples. Dapoxetine was stable in several conditions with recovery rates > 90%. This method was utilized successfully in clinical pharmacokinetic study following oral administration of 60 mg Dapoxetine tablets in 36 healthy male subjects. The result for all 90% confidence intervals were within the preset ranges.The method proved to be highly reproducible and sensitive and thus can be employed in bioequivalence studies and large scale sample analysis of Dapoxetine.

Clinical and Biochemical Assessment of Maintenance Treatment in Chronic Recurrent Seborrheic Dermatitis: Randomized Controlled Study

IntroductionFew studies have investigated the long-term effects of a maintenance regimen in the prevention of relapses in scalp seborrheic dermatitis (SD), in particular following biomarker changes.Materials and methodsA new shampoo containing beta-glycyrrhetinic acid (18βGA) in addition to cyclopiroxolamine (CPO) and zinc pyrithione (ZP) was tested in 67 subjects suffering from SD with moderate to severe erythema and itching in a biphasic study. After a first common intensive treatment phase (investigational product thrice a week × 2 weeks), subjects randomly received the investigational product once a week × 8 weeks (maintenance) or a neutral shampoo (discontinuation) in a comparative, parallel group maintenance phase. Efficacy was assessed clinically (overall clinical dandruff score, erythema, overall efficacy, self-evaluation), biochemically and microbiologically by quantitative polymerase chain reaction (qPCR), high performance liquid chromatography (HPLC) or enzyme-linked immunoabsorbent assay (ELISA) analysis of scale samples (Malassezia species (restricta and globosa), cohesion proteins (plakoglobins), inflammation (Interleukin (IL)-8, IL-1RA/IL-1α) and pruritus (histamine, cathepsin S) markers).ResultsDuring the intensive treatment phase, SD improved significantly (p < 0.0001) with a decrease in clinical signs as well as Malassezia species, cohesion proteins, inflammation and pruritus markers. During the maintenance phase, the improvement persisted in the ‘maintenance’ group only, with a significant intergroup difference. A consistently positive relationship was found between dandruff, itching, erythema and Malassezia populations, histamine levels and IL-1RA/IL-1α ratio.ConclusionThe effectiveness of this maintenance regimen was objectively demonstrated at the clinical, biochemical and microbiological level. Correlations between clinical signs and biomarkers could provide clues to explain the resolution of SD and confirm the interest of biomarkers for SD treatment assessment.Electronic supplementary materialThe online version of this article (doi:10.1007/s13555-014-0047-0) contains supplementary material, which is available to authorized users.

Analysis and Solution of Fouling on Flow Path for Supercritical Steam Turbine

Insufficient output and rising pressure after governing stage of a 630 MW supercritical unit occurred only 18 month after the first outage. Though analysis based on measured parameters, fouling existed in governing stage and the first stage group. By virtue of linearization of formula and decoupling the impacts to thermal characteristic parameters, the quantified deposition degree was obtained. The fouling reason was determined by scale sample analysis, and the solution was proposed by quantitative calculation. The problem was successfully solved with boiler pickling, turbine cascade jet-beading and pulsing minimum oxygen to inhibit flow accelerated corrosion. A steam quality detection method was also proposed as the installation of measurement point after governing stage of supercritical unit. These treatments provided building and operation experience for 1000MW ultra-supercritical turbine and the same type of equipments.

Stable Isotopes of Carbon and Nitrogen Indicate Differences in Marine Ecology between Wild and Hatchery‐Produced Steelhead

AbstractHatchery‐produced anadromous salmonids often differ from their wild conspecifics in behavior, growth, and survival after release, but our understanding of their comparative ecology at sea is very limited. We used stable isotopes of carbon and nitrogen to test the null hypothesis that hatchery‐produced steelhead Oncorhynchus mykiss from Forks Creek in southwestern Washington would be similar in trophic level and marine distribution to wild fish from the same river. Analysis of scale samples from 30 fish of each type that had migrated to sea in 2001 and 2002 (120 fish in all) revealed significant effects of year and origin on both C and N. The values for δ15N were consistent with a higher trophic level for the wild fish (mean = 10.82, SD = 0.57) than for the hatchery fish (mean = 10.51, SD = 0.59), and the δ13C values were consistent with more reliance on nearshore sources of C by wild fish (wild fish mean = −16.52, SD = 0.30; hatchery fish mean = −16.73, SD = 0.31). The wild fish showed no relationship between body size and isotope values, but among the hatchery fish larger individuals tended to have lower δ15N values and more negative δ13C values. The wild fish were, on average, larger than the hatchery fish but had higher δ15N values and less negative δ13C values. These patterns are the opposite of what would be expected from a difference in growth rate, suggesting that the differences arose from ecological processes rather than a size or growth effect. Interactions between trophic level and location prevent a determination of which features of the marine ecology differed between wild and hatchery fish, but either factor could result from differences in the genetic background and rearing history of wild and hatchery fish and could contribute to differences in their performance (growth and survival) at sea.

Evaluation of the moisturizer Pédimed ® in the foot care of diabetic patients

Aim Xerosis is one of the most common abnormalities observed in the diabetic foot, promoting ulceration through the development of fissures and hyperkeratosis. Its treatment is therefore paramount and must be implemented early on. The objective of this study was to assess the moisturizing properties of Pédimed ® cream in the treatment of foot xerosis in diabetic patients. Methods In this randomized double-blind study, Pédimed ® and its placebo were randomly allocated to the right/left foot of each patient (one active/one control side). Products were applied twice daily for 4 weeks. Xerosis was assessed using the clinical Xerosis Assessment Scale (XAS), corneometry (skin hydration measurement) and D-Squame ® (scale sample analysis) after 14 (D14) and 28 (D28) days of treatment. Results Twenty-four men and 30 women, aged 57.0 ± 12.7 years, with type 1 or type 2 diabetes and moderate-to-severe foot xerosis were included. A dramatic decrease in XAS score that was more marked with Pédimed ® than with placebo was observed from D14 (38.1% vs 20.9%, P < 0.0001), reaching 61.9% vs 34.9% at D28 ( P < 0.0001). The number of feet with fissures was greatly reduced with Pédimed ® compared with placebo at both D14 (11.1% vs 22.2%, P = 0.031) and D28 (5.6% vs 18.5%, P = 0.039). Skin hydration increased by 48.9% with Pédimed ® vs 31.7% with placebo at D14 ( P = 0.0002), reaching 57.3% vs 36.5% at D28 ( P < 0.0001). All D-Squame ® parameters showed greater improvement with Pédimed ®. Product tolerability was excellent. Conclusion Validated clinical and paraclinical tools demonstrated the efficacy of Pédimed ® in improving xerosis and reducing fissures of the feet in diabetic patients.

Genetic Assessment of Walleye ( Sander vitreus) Restoration Efforts and Options in Nipigon Bay and Black Bay, Lake Superior

Walleye ( Sander vitreus) stocks in Nipigon Bay and Black Bay historically numbered as the largest stocks in Lake Superior, but collapsed in the 1960s due to overfishing, habitat loss, and other pressures. We used microsatellite DNA analyses to assess the success and relative contributions of past rehabilitation stocking to walleye in Nipigon Bay, and to investigate the relationship between historical and contemporary populations in Black Bay. Based on the genetic data, juvenile stocking and adult transfers from four source populations into Nipigon Bay differed substantially in their contributions to the reestablished population. The genetic data also indicated that natural reproduction was occurring and identified survivors from the former Nipigon Bay population. Similar genetic analysis of scale samples from the historical Black Bay fishery and present-day walleye from a major tributary (Black Sturgeon River) showed that the historical and contemporary samples comprise one genetic stock, which is significantly different from neighboring native and introduced populations. These findings suggest that walleye restoration efforts in Lake Superior are working, and highlight the utility of and options for adaptive management approaches for restoring extirpated populations.

A history of identification to continent of origin of Atlantic salmon ( Salmo salar L.) at west Greenland, 1969–1997

Atlantic salmon caught in the commercial fishery at west Greenland have routinely been identified to continent of origin, viz., North American or European, since 1969, using scale pattern recognition techniques. Although specific details have varied over the 29-year period, the technique generally has remained the same. Discriminant analysis of scale samples collected in the commercial fishery (mixed samples) and a known origin database (training samples) collected in homewaters are used to identify the continental origin of individual fish. The proportions of North American salmon in the catch samples have ranged from a low of 34% in 1971 to a high of 75% in 1990. Comparisons of the North American proportions showed no consistent spatial trends, however, differences were noted in proportions with latitude along the west Greenland coast. The proportions of continent of origin, although varying annually, have generally shown an increasing proportion of North American salmon in recent years. Biological characteristics of individual salmon identified to continent of origin have been used in models to provide catch advice to managers for the west Greenland salmon fishery and to define the impacts of the fishery on salmon stocks.

Sulfide scale formation and control: the case of lead sulfide

The main characteristics of scale encountered in a typical high enthalpy/high salinity geothermal field (Milos island) are summarized. The results of scale sample analysis, coupled with the results of laboratory experiments with model fluids, point in the direction of design and operating conditions, which may significantly mitigate the scaling problems. Carefully controlled brine acidification appears to be a valid option, worth testing in the field. Encouraging results are also obtained in this study on the use of organic scale inhibitors. Their effectiveness, however, must be assessed under field conditions of high temperature and salinity.

The Smallmouth Bass Fishery of South Bay, Lake Huron

The smallmouth bass (Micropterus dolomieui) population of South Bay, Lake Huron and the sport fishery imposed on it have been studied by means of marking and creel census carried out during the years 1947 to 1952 inclusive. Population estimates of legal-sized bass (over 10 inches–fork length), based on the recovery of marked fish, show a decrease from 5,900 fish in 1947 to 2,900 in 1949 with an increase again to 5,700 in 1952. The number of bass caught per 100 rod-hours in these years was 89, 51 and 87, respectively. The recovery of the population from its low in 1949 was due solely to the 1947 year-class which dominated the fishery in 1950, 1951 and 1952, contributing 34%, 71% and 67%, respectively, of the anglers' catch in these years. Analysis of scale samples of the anglers' catch shows considerable variation in year-class strength. In contrast to the 3,500 fish contributed to the anglers' creel by the 1947 year-class, the 1945 year-class contributed only 400 fish.South Bay bass enter the sport fishery in small numbers at age III and 70% of the anglers' catch consisted of age-III to age-V fish. Sixty per cent of the legal-sized population of bass present in South Bay in one year are taken by anglers in the succeeding 4–5 years at the present exploitation.A large percentage of the bass population is located in the Inner Basin of South Bay where they are dispersed in varying concentrations along the shoreline. During the five-year study 3,331 bass were tagged and, although the loss of tags was high, 692 were recaptured by trap nets in the same season they were released. Eighty-five per cent of these were taken within two miles of their release point. Of 60 bass recaptured a year after tagging, 43 (72%) were taken within two miles of their release point. Only five per cent of all recorded recaptures were caught over five miles from their release point. Larger bass tended to range farther than small bass.