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مرکز اطلاعات علمی SID1
اسکوپوس
مرکز اطلاعات علمی SID
ریسرچگیت
strs
Issue Info: 
  • Year: 

    2012
  • Volume: 

    5
  • Issue: 

    3 (19)
  • Pages: 

    39-52
Measures: 
  • Citations: 

    0
  • Views: 

    39815
  • Downloads: 

    9206
Abstract: 

Investigations are carried out to evaluate the performance of a low HEAT REJECTION (LHR) diesel engine consisting of air gap insulated piston with 3-mm air gap, with superni (an alloy of nickel) crown and air gap insulated liner with superni insert with different operating conditions of crude jatropha oil with varied injection timing and injection pressure. Performance parameters of brake thermal efficiency (BTE), exhaust gas temperature (EGT) and volumetric efficiency (VE) are determined at various magnitudes of brake mean effective pressure. Pollution levels of smoke and oxides of nitrogen (NOx) are recorded at the peak load operation of the engine. Combustion characteristics of the engine of peak pressure (PP), time of occurrence of peak pressure (TOPP), maximum rate of pressure rise (MRPR) and time of occurrence of maximum rate of pressure (TOMRPR) are measured with TDC (top dead centre) encoder, pressure transducer, console and special pressure-crank angle software package. Zero dimensional, multi-zone combustion model is assumed to predict combustion characteristics and validated with experimental results. Conventional engine (CE) showed deteriorated performance, while LHR engine showed improved performance with crude jatropha oil operation at recommended injection timing and pressure and the performance of both version of the engine is improved with advanced injection timing and higher injection pressure when compared with CE with operating on pure diesel. Peak brake thermal efficiency increased by 4%, smoke levels decreased by 4% and NOx levels increased by 37% with vegetable oil operation on LHR engine at its optimum injection timing, when compared with pure diesel operation on CE at manufacturer’s recommended injection timing.

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Issue Info: 
  • Year: 

    2018
  • Volume: 

    8
  • Issue: 

    2
  • Pages: 

    2679-2691
Measures: 
  • Citations: 

    0
  • Views: 

    22590
  • Downloads: 

    10868
Abstract: 

The thermal balance analysis is a useful method to determine energy distribution and efficiency of internal combustion (IC) engines. In engines cooling concepts, estimation of HEAT transfer to brake power ratio, as one of the most significant performance characteristics, is highly demanded. In this paper, investigation of energy balance and derivation of specific HEAT REJECTION is carried out experimentally and numerically. Experiments are carried out on an air-cooled, single cylinder, four-stroke gasoline IC engine. The engine is simulated numerically and after validation with experimental data, the code is run to find out total and instantaneous thermal balance of engine. Results indicate that about onethird of fuel energy is converted to brake power and major part of energy is dissipated through exhaust and HEAT transfer. Experimental and numerical results show that by increasing engine speed, HEAT transfer to brake power ratio decreases. It is also observed that increasing engine speed leads to increase of exhaust power to brake power ratio. Finally two correlations for estimation of HEAT transfer and exhaust power to brake power ratios are obtained.

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Issue Info: 
  • Year: 

    2012
  • Volume: 

    1
  • Issue: 

    2
  • Pages: 

    99-110
Measures: 
  • Citations: 

    0
  • Views: 

    42020
  • Downloads: 

    11300
Abstract: 

Experiments were conducted to evaluate the performance of a low HEAT REJECTION (LHR) diesel engine. Performance parameters and emission levels were determined at various magnitudes of brake mean effective pressure. Combustion characteristics of the engine were measured with TDC (top dead centre) encoder, pressure transducer, console and special pressure-crank angle software package at peak load operation of the engine. Conventional engine (CE) and LHR engine showed improved performance at recommended injection timing of 27obTDC and recommended injection pressure of 190 bar, when compared with CE with pure diesel operation. Peak brake thermal efficiency increased by 18%, smoke levels decreased by 48% and NOx levels decreased by 38% with LHR engine relatively at its optimum injection timing and maximum induction of ethanol when compared with pure diesel operation of CE at manufacturer’s recommended injection timing.

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گارگاه ها آموزشی
Issue Info: 
  • Year: 

    2003
  • Volume: 

    15
  • Issue: 

    -
  • Pages: 

    89-94
Measures: 
  • Citations: 

    397
  • Views: 

    13337
  • Downloads: 

    17487
Keywords: 
Abstract: 

Yearly Impact:

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Author(s): 

ROHNER R.P.

Journal: 

AMERICAN PSYCHOLOGIST

Issue Info: 
  • Year: 

    2004
  • Volume: 

    59
  • Issue: 

    -
  • Pages: 

    827-840
Measures: 
  • Citations: 

    376
  • Views: 

    14378
  • Downloads: 

    14360
Keywords: 
Abstract: 

Yearly Impact:

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Author(s): 

Khankari g. | Karmakar s.

Issue Info: 
  • Year: 

    2018
  • Volume: 

    31
  • Issue: 

    10 (TRANSACTIONS A: Basics)
  • Pages: 

    1789-1795
Measures: 
  • Citations: 

    0
  • Views: 

    13155
  • Downloads: 

    8927
Abstract: 

This paper proposes an approach for improving the plant efficiency by reducing the HEAT REJECTION temperature of power cycle using Kalina Cycle System 11 (KCS11) which is integrated at the steam condenser of a 500 MWe SubC (subcritical) coal-fired power plant. It is modelled by using power plant simulation software ‘ Cycle Tempo’ at different plant operating conditions. Results show that the additional net electric power of 5. 14 MWe from KCS11 improves the net energy and exergy efficiencies of the power plant by about 0. 302 % point and 0. 27 % point, respectively at full load over the stand-alone coal-fired steam power plant. Thereby, the carbon dioxide (CO2) emission is reduced by about 2. 02 t/h at full load. Combined plant efficiencies decrease with decrease in evaporator outlet temperature due to decrease in vapour quality of binary mixture at turbine inlet and higher steam turbine back pressure. Levelized Cost of Electricity (LCoE) generation and payback period of the combined cycle power plant are about Rs 1. 734 and 4. 237 years, respectively and the cost of fuel saving is about Rs 0. 685 per kg of coal which is lower than the fuel cost.

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strs
Author(s): 

GANJI M.R. | BOROUMAND BEHROUZ

Issue Info: 
  • Year: 

    2007
  • Volume: 

    1
  • Issue: 

    2
  • Pages: 

    54-56
Measures: 
  • Citations: 

    0
  • Views: 

    75754
  • Downloads: 

    31209
Abstract: 

The incidence of acute REJECTION of the kidney allograft in the world has been around 15% during the period between 2001 and 2003. It is clinically defined as an elevation in the level of serum creatinine by more than 0.3 mg/dL and is diagnosed by kidney biopsy. On pathologic examination, the interstitium of the allograft is diffusely edematous and infiltrated by CD4 and CD8 lymphocytes. Tubulitis occurs when the lymphocytes and monocytes extend into the walls and lumina of the tubules. Presence of leukocytes determines infection or antibody-mediated REJECTION. Typically C4d staining is negative. Other causes of acute allograft dysfunction included prerenal factors, interstitial nephritis, infection, acute tubular necrosis, toxicity by drugs, and obstruction in the urinary tract.The primary diagnostic assessments include history, especially adherence to immunosuppressive therapy, physical examination, blood and urine laboratory tests, measurement of the serum levels of the drugs, and ultrasonography. Diagnosis of acute cellular REJECTION depends on biopsy, CD20 staining for refractory cases, negative C4d staining, presence of markers of activating lymphocyte, and proteomic study. Treatment of acute cellular REJECTION in kidney transplant recipients include pulse steroid for the first REJECTION episode. It can be repeated for recurrent or resistant REJECTION. Thymoglobulin and OKT3 are used as the second line of treatment if graft function is deteriorating. Changing the protocol from cyclosporine to tacrolimus or adding mycophenolate mofetil or sirolimus might be effective. Prognosis depends on number of REJECTION episodes, the use of potent drugs, time of REJECTION from transplantation, and response to treatment.

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Journal: 

BINA

Issue Info: 
  • Year: 

    2017
  • Volume: 

    22
  • Issue: 

    3
  • Pages: 

    238-242
Measures: 
  • Citations: 

    0
  • Views: 

    448
  • Downloads: 

    168
Abstract: 

Purpose: To describe the clinical features, management, and visual outcome in a case of stromal REJECTION with a rare and unusual presentation after deep anterior lamellar keratoplasty (DALK).Case report: A 25-year-old healthy man with advanced keratoconus underwent DALK using the standard big bubble technique in his right eye. Five months after surgery, the patient involved in red eye, decreased vision, acute epithelial edema, acute and diffuse stromal edema, fine diffuse keratic precipitates (KPs) in the graft location and AC (anterior chamber) inflammation with cells and flair without any vascularization in the graft and recipient bed, and any infiltration or loosening of the sutures. Management with topical and systemic steroids, and topical antibiotic lead to complete resolution of stromal edema, KPs and AC inflammation. Nine months after the first episode, the patient was referred due to the same clinical presentation and similar findings on examination. Recurrence was treated successfully with the same prior medications and clear graft was achieved.Conclusion: Although there is no endothelial immune reaction after DALK for keratoconus, stromal graft REJECTION after DALK can be presented with the same features as endothelial graft REJECTION and should be differentiated from herpes simplex virus (HSV) keratouveitis.

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Author(s): 

RYAN J.M. | BARRY F.P.

Issue Info: 
  • Year: 

    2005
  • Volume: 

    2
  • Issue: 

    -
  • Pages: 

    0-0
Measures: 
  • Citations: 

    363
  • Views: 

    11118
  • Downloads: 

    12816
Keywords: 
Abstract: 

Yearly Impact:

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Author(s): 

SCHUURMAN H.J. | CHENG J.

Journal: 

XENOTRANSPLANTATION

Issue Info: 
  • Year: 

    2003
  • Volume: 

    10
  • Issue: 

    4
  • Pages: 

    293-299
Measures: 
  • Citations: 

    371
  • Views: 

    11858
  • Downloads: 

    13760
Keywords: 
Abstract: 

Yearly Impact:

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