Atomization of Crude and Residual Fuel Oils

1979 ◽  
Vol 101 (2) ◽  
pp. 250-258 ◽  
Author(s):  
A. K. Jasuja
Keyword(s):  
High Viscosity ◽  
Fuel Oil ◽  
Turbine Engine ◽  
Residual Fuel Oil ◽  
Fuel Oils ◽  
Data Points ◽  
The Mean ◽  
The Difference ◽  
The Many ◽  
Pressure Swirl

A study is made of the effects that fuel properties have upon the mean droplet size characteristics of three fuel atomizer types that are commonly employed in the gas turbine engine. The fuels tested included kerosine, gas oil, and a heavy residual fuel oil, and each was passed through a pressure swirl jet, a prefilming airblast, and a plain-jet airblast atomizer in turn. Tests were carried out at pressure levels close to ambient and mean drop sizes were determined using a light-scattering technique. Two main points emerge from the results: Firstly, for all atomizers tested, that the existing dropsize correlations are not sufficiently accurate for use with the high-viscosity residual fuel oils. Secondly, that the fuel dropsize decreases with the change in atomizer type from plain-jet airblast to prefilming airblast. The difference in performance of the two types of airblast atomizers is most noticeable for the residual fuel oil, particularly so at pressure drop levels of less than around five percent. Use is also made of the many data points collected to derive improved dropsize correlations which may be used over the whole range of fuels tested.

scholarly journals Plain-Jet Airblast Atomization of Alternative Liquid Petroleum Fuels Under High Ambient Air Pressure Conditions

1982 ◽  
Author(s):  
A. K. Jasuja
Keyword(s):  
Ambient Air ◽  
High Viscosity ◽  
Fuel Oil ◽  
Similar Data ◽  
Gas Oil ◽  
Turbine Engine ◽  
Residual Fuel Oil ◽  
Wide Range ◽  
Petroleum Fuels ◽  
Light Scattering Technique

An investigation has been conducted of the effects that air and fuel properties have upon the spray mean dropsize characteristics of a plain-jet airblast atomizer of the type employed in the gas turbine engine. The fuels tested included kerosine, gas oil and a high-viscosity blend of gas oil in residual fuel oil. The tests covered a wide range of ambient air pressures. Well established laser light-scattering technique was employed for dropsize measurements. The experimental data collected in the present investigation are presented in this paper and comparisons are made against similar data relating to the pre-filming type of airblast atomizer, collected in an earlier study (2).

Airblast Atomization of Alternative Liquid Petroleum Fuels under High Pressure Conditions

1981 ◽  
Vol 103 (3) ◽  
pp. 514-518 ◽  
Author(s):  
A. K. Jasuja
Keyword(s):  
Fuel Oil ◽  
Gas Oil ◽  
Sauter Mean Diameter ◽  
Turbine Engine ◽  
Residual Fuel Oil ◽  
Wide Range ◽  
The Mean ◽  
Petroleum Fuels ◽  
Correlating Equation ◽  
Light Scattering Technique

A study has been conducted of the effects that fuel and air properties have upon the mean droplet size characteristics of a pre-filming airblast atomizer of the type commonly employed in the gas turbine engine. The fuels tested included kerosine, gas oil and two blends of gas oil in residual fuel oil. The tests were carried out over a wide range of air pressures (about 1 to 13 atmospheres), fuel viscosities (about 0.001 to 0.037 Ns/m2) and the spray mean drop sizes were measured using a laser light-scattering technique. The experimental data accumulated in the study is presented in the paper and it is concluded that the spray Sauter Mean Diameter performance of the atomizer studied can be predicted to a reasonable degree of accuracy, over the range of conditions studied, by a relatively simple correlating equation.

scholarly journals Relationship Between Erosion and Characteristics of Deposits in Gas Turbines Burning Heavy High Sulfur Fuel Oil

1994 ◽  
Author(s):  
Adriana Wong-Moreno ◽  
Alicia Sánchez-Villalvazo
Keyword(s):  
Gas Turbines ◽  
Fuel Oil ◽  
Clear Correlation ◽  
Inlet Temperature ◽  
Operation Conditions ◽  
Residual Fuel Oil ◽  
Fuel Oils ◽  
Severe Erosion ◽  
Heavy Fuel Oils ◽  
Physical And Chemical

Heavy, brittle and very hard deposits built on the first row vanes have caused severe erosion of all the first stage blades of a gas turbine during operation with washed and treated heavy residual fuel oil. The high sulphur (3.5–4.0 wt.%) fuel oil consumed by the turbine is also high in vanadium (280–290 ppm) and asphaltene content. In the present work the results of an investigation on the physical and chemical characteristics of erosive ash deposits as a function of operation conditions and fuel oil characteristics are presented. The structure and chemistry of deposits were studied by chemical analysis, x-ray diffraction, microanalysis and scanning electron microscopy. It was confirmed that deposit friability is enhanced by its MgSO4 content and that its hardness depends on the amount of MgO present. It was also found a clear correlation between the gas inlet temperature and the size of the ash particles deposited, and on the degree of compactness and hardness of the deposit. The role of the unburned particles, unavoidable in the combustion of heavy fuel oils, is discussed in relation to their influence on the effectiveness of the magnesium inhibitor.

Correlation Between Gastrocnemius Tightness and Heel Pain Severity in Plantar Fasciitis

2020 ◽  
pp. 107110072095514
Author(s):  
Christopher J. Pearce ◽  
Dexter Seow ◽  
Bernard P. Lau
Keyword(s):  
Plantar Fasciitis ◽  
Case Series ◽  
Heel Pain ◽  
Level Of Evidence ◽  
Data Points ◽  
The Mean ◽  
The Difference ◽  
Night Splint ◽  
Gastrocnemius Tightness

Background: It is known that there is an association between gastrocnemius tightness and plantar fasciitis, but this has never been quantified. The purpose of the study was to determine the correlation between gastrocnemius tightness and the severity of heel pain in plantar fasciitis. Methods: Thirty-three patients were prescribed physiotherapist-directed gastrocnemius stretching exercises, a Strassburg Sock or night splint, and silicone heel insoles as required. Outcome measures included (1) gastrocnemius tightness, (2) 100-mm visual analog scale (VAS) for pain on the first steps in the morning, and (3) 100-mm VAS for the worst pain felt during the previous week. Gastrocnemius tightness was measured by the difference in maximal ankle dorsiflexion between knee bent and straight with a goniometer. Results: The mean gastrocnemius tightness was 22 degrees at baseline compared with 9 degrees at the final follow-up ( P < .01). A reduction in VAS for pain on the first steps in the morning and VAS for the worst pain felt during the previous week from baseline to final follow-up was observed ( P < .01). Correlation analysis of 105 data points between gastrocnemius tightness and VAS for pain on the first steps in the morning was R = 0.757 ( P < .001), and between gastrocnemius tightness and VAS for the worst pain felt during the previous week was R = 0.781 ( P < .001). Conclusion: The study observed a strong, statistically significant correlation between gastrocnemius tightness and the severity of heel pain in plantar fasciitis. Level of Evidence: Level IV, case series.

scholarly journals EIS Evaluation of Fe, Cr, and Ni in NaVO3at 700°C

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
O. Sotelo-Mazón ◽  
J. Porcayo-Calderon ◽  
C. Cuevas-Arteaga ◽  
J. J. Ramos-Hernandez ◽  
J. A. Ascencio-Gutierrez ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Combustion Products ◽  
Corrosion Process ◽  
Fuel Oil ◽  
High Grade ◽  
Residual Fuel Oil ◽  
Fuel Oils ◽  
Heavy Fuel Oils ◽  
Steam Boilers ◽  
Nickel Base

Due to the depletion of high-grade fuels and for economic reasons, use of residual fuel oil in energy generation systems is a common practice. Residual fuel oil contains sodium, vanadium, and sulphur as impurities, as well as NaCl contamination. Metallic dissolution caused by molten vanadates has been classically considered the main corrosion process involved in the degradation of alloys exposed to the combustion products of heavy fuel oils. Iron and nickel base alloys are the commercial alloys commonly used for the high temperature applications, for example, manufacture of components used in aggressive environments of gas turbines, steam boilers, and so forth. Therefore, because the main constituents of these materials are Fe, Cr, and Ni, where Cr is the element responsible for providing the corrosion resistance, in this study the electrochemical performance of Fe, Cr, and Ni in NaVO3at 700°C in static air for 100 hours was evaluated.

Emulsification Characteristics of Marine Fuel Oils with Water

1995 ◽  
Vol 39 (01) ◽  
pp. 86-94
Author(s):  
Cherng-Yuan Lin ◽  
Chein-Ming Lin ◽  
Cheh-Skiung Chen
Keyword(s):  
Emulsion Stability ◽  
Test Tube ◽  
Fuel Oil ◽  
Water Droplets ◽  
Marine Fuel ◽  
Residual Fuel Oil ◽  
Saturated State ◽  
Fuel Oils ◽  
Mean Diameter ◽  
Distillate Fuel

The effects of water-to-oil ratio, surfactant content, stayed time, and homogenizing speed on the emulsification characteristics of emulsion activity, emulsion stability, and mean micro-water-droplets diameter for a light distillate fuel oil and a heavy residual fuel oil are experimentally investigated. It is revealed that after centrifuging, the emulsion of the distillate fuel separates into four distinct layers from top to bottom of a test tube. Also, an emulsion of the distillate fuel oil emulsified with surfactant Span 20 is shown to have more fluctuating variations of emulsion activity and mean diameter of water droplets with homogenizing speed. A saturated state of the emulsion with the surfactant addition appears as the surfactant content = 1.5 to 2.0%. Higher surfactant content than 2% is shown to deteriorate the emulsification characteristics of these fuel oils. In addition, the residual fuel oil is found to have better emulsification characteristics in comparison with the distillate fuel oil.

scholarly journals Luaran Terapi Berdasarkan Jenis Pemberian Analgetik pada Pasien Pasca Operasi Ortopedi

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Nurul Irna Windari ◽  
Zullies Ikawati, Apt. ◽  
Eni Purwaningtyastuti
Keyword(s):  
Postoperative Pain ◽  
Orthopedic Surgery ◽  
Postoperative Pain Management ◽  
Exact Test ◽  
Independent Variable ◽  
The Mean ◽  
The Difference ◽  
The Many ◽  
Fentanyl Administration ◽  
Intravenous Ketorolac

Postoperative pain was suffered by 80% of the total patients. One of the many surgical procedures performed is orthopedics. Ketorolac and fentanyl are often used for postoperative orthopedic pain. Appropriate postoperative pain management with adequate analgesic administration will accelerate pain reduction and shorten the patient's hospital stay. This study aims to determine the difference in the effect of continuous fentanyl and intravenous ketorolac on pain targets achievement and Length of Stay (LOS) of patients after orthopedic surgery. This study is a prospective cohort study, involving inpatients after orthopedic surgery in Dr. Sardjito Yogyakarta in July-October 2019. The independent variable is continuous fentanyl and intravenous ketorolac, while the dependent variable is the achievement of pain targets and LOS. The analysis was conducted by Fisher's exact test, Mann Whitney's test, and multivariate analysis to determine the dominance of variables on the research outcomes. There were 59 patients after orthopedic surgery in this study. A total of 34 patients in the continuous fentanyil group and 25 patients in the intravenous ketorolac group. There was no difference in the effect of continuous fentanyl administration and intravenous ketorolac on pain targets achievement (P = 0.711), while there were differences in the effect of continuous fentanyl administration and intravenous ketorolac on the average LOS of patients in the hospital (P = 0,000). Continuous fentanyl and intravenous ketorolac can both produce the achievement of adequate postoperative orthopedic pain targets, but the mean LOS becomes shorter in patients with intravenous ketorolac.

Ratio imaging of intracellular ion concentration

1992 ◽  
Vol 50 (2) ◽  
pp. 1160-1161
Author(s):  
Stephen R. Bolsover
Keyword(s):  
Individual Cell ◽  
Video Camera ◽  
Field Of View ◽  
Ion Concentration ◽  
Fluorescence Signal ◽  
Ion Imaging ◽  
Ratiometric Fluorescence ◽  
Ratio Imaging ◽  
The Mean ◽  
The Many

The field of intracellular ion concentration measurement expanded greatly in the 1980's due primarily to the development by Roger Tsien of ratiometric fluorescence dyes. These dyes have many applications, and in particular they make possible to image ion concentrations: to produce maps of the ion concentration within living cells. Ion imagers comprise a fluorescence microscope, an imaging light detector such as a video camera, and a computer system to process the fluorescence signal and display the map of ion concentration.Ion imaging can be used for two distinct purposes. In the first, the imager looks at a field of cells, measuring the mean ion concentration in each cell of the many in the field of view. One can then, for instance, challenge the cells with an agonist and examine the response of each individual cell. Ion imagers are not necessary for this sort of experiment: one can instead use a system that measures the mean ion concentration in a just one cell at any one time. However, they are very much more convenient.

The Effect of Vocabulary Intervention on Text Comprehension: Who Benefits?

2019 ◽  
Vol 50 (4) ◽  
pp. 562-578 ◽  
Author(s):  
Dawna Duff
Keyword(s):  
Middle School ◽  
Reading Comprehension ◽  
Text Comprehension ◽  
Classroom Instruction ◽  
Vocabulary Instruction ◽  
Clinical Intervention ◽  
Vocabulary Knowledge ◽  
Vocabulary Intervention ◽  
The Mean ◽  
The Difference

Purpose Vocabulary intervention can improve comprehension of texts containing taught words, but it is unclear if all middle school readers get this benefit. This study tests 2 hypotheses about variables that predict response to vocabulary treatment on text comprehension: gains in vocabulary knowledge due to treatment and pretreatment reading comprehension scores. Method Students in Grade 6 ( N = 23) completed a 5-session intervention based on robust vocabulary instruction (RVI). Knowledge of the semantics of taught words was measured pre- and posttreatment. Participants then read 2 matched texts, 1 containing taught words (treated) and 1 not (untreated). Treated texts and taught word lists were counterbalanced across participants. The difference between text comprehension scores in treated and untreated conditions was taken as a measure of the effect of RVI on text comprehension. Results RVI resulted in significant gains in knowledge of taught words ( d RM = 2.26) and text comprehension ( d RM = 0.31). The extent of gains in vocabulary knowledge after vocabulary treatment did not predict the effect of RVI on comprehension of texts. However, untreated reading comprehension scores moderated the effect of the vocabulary treatment on text comprehension: Lower reading comprehension was associated with greater gains in text comprehension. Readers with comprehension scores below the mean experienced large gains in comprehension, but those with average/above average reading comprehension scores did not. Conclusion Vocabulary instruction had a larger effect on text comprehension for readers in Grade 6 who had lower untreated reading comprehension scores. In contrast, the amount that children learned about taught vocabulary did not predict the effect of vocabulary instruction on text comprehension. This has implications for the identification of 6th-grade students who would benefit from classroom instruction or clinical intervention targeting vocabulary knowledge.

Efficacy and Safety of Oral Ivermectin and Topical Permethrin in the Treatment of Scabies

2020 ◽  
Vol 33 (1) ◽  
pp. 41-47
Author(s):  
Mohsena Akhter ◽  
Ishrat Bhuiyan ◽  
Zulfiqer Hossain Khan ◽  
Mahfuza Akhter ◽  
Gulam Kazem Ali Ahmad ◽  
...  
Keyword(s):  
Skin Diseases ◽  
Close Contact ◽  
Randomized Study ◽  
Sarcoptes Scabiei ◽  
Efficacy And Safety ◽  
Common Skin ◽  
Group A ◽  
The Mean ◽  
The Difference ◽  
Group B

Background: Scabies is one of the most common skin diseases in our country. It is caused by the mite Sarcoptes scabiei var hominis, which is an ecto-parasite infesting the epidermis. Scabies is highly contagious. Prevalence is high in congested or densely populated areas. Individuals with close contact with an affected person should be treated with scabicidal which is available in both oral and topical formulations. The only oral but highly effective scabicidal known to date is Ivermectin. Amongst topical preparations, Permethrin 5 % cream is the treatment of choice. Objective: To evaluate the efficacy & safety of oral Ivermectin compared to topical Permethrin in the treatment of scabies. Methodology: This prospective, non-randomized study was conducted at the out-patient department of Dermatology and Venereology of Shaheed Suhrawardy Medical College & Hospital over a period of 6 months, from August 2016 to January 2017. The study population consisted of one hundred patients having scabies, enrolled according to inclusion criteria. They were divided into two groups. group A was subjected to oral Ivermectin and the group B to Permethrin 5% cream. Patients were followed up on day 7 and 14 for assessment of efficacy and safety. Result: The mean scoring with SD in group A (Ivermectin) and group B (Permethrin) were 8.26 ± 2.22 and 7.59 ± 2.01 respectively at the time of observation. The difference between the mean score of the two group is not significant (p=0.117) the mean scoring with SD in group A and group B were 4.54 ± 2.05 and 1.64 ± 1.84 respectively at 7thdays. The difference between the mean score of the two group is significant (p<0.001). The mean scoring with SD in group A and group B were 2.68± 2.35 and .36± 1.10 respectively at 14th day difference between the mean score of the group is significant (p<0.001). Conclusion: Topical application of permethrin 5% cream is more effective and safer than oral Ivermectin in the treatment of scabies. TAJ 2020; 33(1): 41-47

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