• Corrosion Science and Technology
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• v.6 no.1
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• pp.12-17
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• 2007

Portland cement incorporating supplementary cementing material develops excellent mechanical properties and long term durability characteristics. India is a leading rice producing country and rice husk is considered as waste in the rice milling industries. In this present work, the rice husk ash (RHA) was added to concrete as cement replacement from 0 to 30%. Corrosion performance of reinforcing steel embedded in RHA blended concretes was studied using linear polarization, AC impedance and gravimetric methods. The corrosion rate of steel bars embedded in RHA concretes were compared with control concrete. The results clearly indicate that the corrosion rate of reinforcing steel embedded in concrete is significantly reduced with the incorporation of RHA. A good correlation among gravimetric method and electrochemical methods was observed. Electrochemical impedance study showed 98 percentage reduction in corrosion rate to the RHA blended concrete with 15% replacement than control concrete.

• Journal of the Korea Society for Simulation
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• v.33 no.1
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• pp.27-34
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• 2024

This study aims to propose an optimal asset allocation that minimizes the risk of insufficient realized replacement rates compared to the OECD average replacement rate. To do this, we set the shortfall risk of replacement rates and calculates an asset allocation plan to minimize this risk based on the period of enrollment, the income level and additional contribution. We consider stocks and deposits as investment assets, using Monte Carlo simulation with a GBM model to generate return distributions for stocks. Our result show that, for individuals with a enrollment period of less than 30 years, participants should invest a minimum of 70-80% of their funds in risky assets to minimize the shortfall risk. However, the proportion of funds that need to be invested in risky assets declines significantly when participants contribute an additional premiums. This effect is particularly pronounced among low-income individuals. Therefore, to achieve OECD average replacement rates, the government needs to incentivize participants to invest more in risky assets, while also providing policies to encourage additional contributions, especially for the low-income population.

• Journal of Chest Surgery
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• v.28 no.4
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• pp.346-354
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• 1995

Records of 71 consecutive patients who had received multiple valve replacement were reviewed[34male,37female,mean age 40.5$\pm$11.2 <14-63> . The early death rate was 2.8%[2/71 . A completed follow-up rate of 95.7% was accomplished in these 69 patients who left hospital[mean 42.5 $\pm$29.5 patients-years . Five of these patients died. The late death rate was 7.2%. Four patients experienced anticoagulant-related hemorrhage[all were minor . One patient had a thromboembolic episode[permanent ,and 2 had late prosthetic valve endocarditis. There was no clinical evidence of hemolysis and structural failure of valves used. Of those patients who survived,NYHA functional class improved significantly[from 87.2% class III & IV before to 95.8% class I & II after . Linearized rates for thromboembolism and anticoagulant-related hemorrhage,and for prosthetic valve endocarditis were 0.67%/100 patient-years,2.95%/100 patient-years,1.34%/100 patient-years, respectively. The actuarial estimates of incidence free of all complications and valve-related deaths were 92.2%/patient-years.Despites the advanced heart disease involving two or more native valves, the patients who had multiple valve replacement had very good results, over a 9-year period.

• Journal of Chest Surgery
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• v.25 no.1
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• pp.57-65
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• 1992

St.Jude Medical cardiac valve replacement was performed in 322 patients: 191 had mitral, 58 had aortic, 72 had double valve and 3 had tricuspid valve replacement. Motality rate in early period was 2.8%[9 patients]. The most common cause of early death was low cardic output syndrome. Follow up extended from 1 to 90 months[mean: 34 months] in 292 patients among 313 in all surviving patients [93.6%]. There were thrombolic complications in eighteen patients. The probability of free from thromboembolism at 5 yerars in MVR, AVR and DVR were 84.7%, 91.8% and 90.2% respectively. And also, actuarial event free rate at 5 years in MVR, AVR and DVR were 80.1%, 82.2%, and 81.4% respectively. There were fourteen late death during follow up period: six from thromboembolism, one from hemorrhage and the others from non valve related -or unknown complications. The acturial survival rate at 5 years were 93.1% in mitral, 92.1% in aortic and 97.1% in double valve replacement. In conclusion, the performance of the St. Jude Mecanical valve compares most favorably with other artificial valves. But it remains still hazards of mechanical prosthesis such as thromboembolism and anticoagulant related hemorrhage.

• Journal of Chest Surgery
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• v.27 no.2
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• pp.122-127
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• 1994

A retrospective study of 737 consecutive patients surviving the first 24 hours who underwent valve replacement surgery from July 1980 to June 1993 was undertaken to determine the prevalence, variables that could be used to predict outcome and results of therapy for postoperative acute renal failure[ARF]. Twenty-one patients[2.8 %] developed acute renal failure. Positive risk factors noted in the development of postoperative renal failure included age, New York Heart Association class III & IV, endocarditis and elevated preoperative concentration of serum creatinine. The duration of cardiopulmonary bypass, aortic cross-clamping and the total duration of the operation also closely correlated with the incidence of ARF. The mortality rate for established ARF was 38.1% and ARF was associated with a significant increase in the length of hospitalization, ventilator support and intensive care unit stay. The incidence and mortality rate of oliguric renal failure was 38.1% and 85.7%. The highest mortality rate was associated with two or more postoperative complications and serum creatinine value exceeded 5 mg/dl. We concluded that therapy should be aimed at prevention of oliguric renal failure, or at least its conversion to nonoliguric renal failure, and early institution of renal replacement therapy with intensive support probably gives the best chance for survival.

• Journal of Chest Surgery
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• v.27 no.8
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• pp.664-668
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• 1994

A total of 217 patients underwent single mitral valve replacement [MVR] with the St. Jude Medical valve between September 1984 and the end of 1992. There were 86 males and 131 females with a mean age of 34.6 $\pm$ 14.4 years[range 5 months-61 years]. A previous valve replacement had been performed in 46 patients [21.2 %]. An early mortality rate was 7.4 % [5.2 % in primary MVR; and 15.2 %in re-replacement MVR]. Early survivors of 201 patients were followed up for a total of 934.5 patient-years[mean 4.7 $\pm$ 2.1years]. A late mortality rate was 2.5 % or 0.54%/patient-year. The linearized rates of thromboembolism, valve thrombosis and anticoagulation-related bleeding were 1.301 %, 0.214 % and 0.428 %/patient-year, respectively. The actuarial survival including operative mortality was 89.9 % $\pm$ 2.1% at postoperative 10 years. The freedom from thromboemolism was 91.3 %$\pm$ 2.5% and the actuarial estimate of incidence free from late deaths and all complications were 80.9 % $\pm$ 3.8 % at 10 years. There were no mechanical failures. In summary, the St. Jude Medical prosthesis performed satisfactorily with an acceptable rate of late complications.

• Korean Journal of Materials Research
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• v.32 no.3
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• pp.115-124
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• 2022

Porous basalt aggregate is commonly used in roadbed engineering, but its application in concrete has rarely been studied. This paper studies the application of porous basalt in concrete. Porous basalt aggregate is assessed for its effects on mechanical strength and durability of prepared C50 concrete; because it has a hole structure, porous basalt aggregate is known for its porosity, and porous basalt aggregates can be made full of water through changing the content of saturated basalt; after full-water condition is achieved in porous basalt aggregate mixture of C50 concrete, we discuss its mechanical properties and durability. The effects of C50 concrete prepared with basalt aggregate on the compressive strength, water absorption, and electric flux of concrete specimens of different ages were studied through experiments, and the effects of different replacement rates of saturated porous basalt aggregate on the properties of concrete were also studied. The results show that porous basalt aggregate can be prepared as C50 concrete. For early saturated porous basalt aggregate concrete, its compressive strength decreases with the increase of the replacement rate of saturated aggregate; this occurs up to concrete curing at 28 d, when the replacement rate of saturated basalt aggregate is greater than or equal to 40 %. The compressive strength of concrete increases with the increase of the replacement rate of saturated aggregate. The 28 d electric flux decreases with the increase of the replacement rate of saturated aggregate, indicating that saturated porous basalt aggregate can improve the chloride ion permeability resistance of concrete in later stages.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.1
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• pp.45-54
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• 2002

Ninety lactating goats (Bachthao, Barbary, Beetal and Jamnapary breeds) were used in an experiment to investigate the replacement value of the tree fodders Flemingia (Flemingia macrophylla) and Jackfruit (Artocarpus heterophyllus). The foliages were used to replace the concentrate in diets based on chopped whole sugar cane (Sacharatum sp.), Para grass (Brachiaria mutica) and dried cassava root (Manihot esculanta). The concentrate was replaced by foliage of Jackfruit or Flemingia at 0%, 20%, 40%, 60% and 80% based on the crude protein (CP) content in the concentrate and foliages, respectively. Average milk yield was 1,617 g/day for goats fed Jackfruit compared to 1,532 g/day for those fed Flemingia. Increasing amounts of Flemingia foliage resulted in reduced dry matter intake and decreased milk yield but milk composition (CP, casein and fat content) was similar up to 60% replacement. Flemingia showed a poor potential as a supplement for lactating goats and replacement levels should not exceed 20% of the protein in the concentrate or 7.5% of the dry matter in the diet. With respect to the combination of milk production and net return over the control a CP replacement rate of 20% was the most promising. For Jackfruit there was similar feed intake and milk yield at a replacement level of 20% of CP in the concentrate (9.2% of DM intake) compared to the control diet. Milk yield at the level of 40% replacement (15% of the DM) in the diet was slightly reduced. Up to a level of CP replacement rate of 60% (21% DM in the diet) can be suggested for on-farm testing as a higher net return over the control was obtained on station.

• Journal of Chest Surgery
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• v.31 no.3
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• pp.247-254
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• 1998

A total of 172 cases of MVR using the St. Jude Medical valve was conducted in the period from August 1986 to May 1996. The hospital mortality rate was 3.5% (n=6) and the late mortality rate was 3.3% (n=5). According to the follow-up of 161 surviving patients, the average length of survival was 50.23$\pm$0.27 months. Three cases of prosthetic valve related complication deaths were identified. Two cases could be ascribed to left atrial thrombi and resulting cerebral infarction, and one case was prosthetic valve endocarditis. Two cases were caused by hemorrhagic complications that we presume to have been accompanied by anti-coagulation therapy. The actuarial survival rate of all cases at 10 years was 92.3%. We conclude that good clinical results and a low complication rate could be achieved through mitral valve replacement with the St. Jude Medical valve. We also conclude that mid-term and long-term follow-ups were instrumental and necessary.

• Journal of Chest Surgery
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• v.20 no.2
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• pp.281-288
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• 1987

A total and consecutive 163 patients underwent cardiac valve replacement using the Hancock porcine xenograft cardiac valves from 1 976 to 1984. Of 198 substitute valves, 177 were the Hancock valves. One hundred twenty-nine patients[79.1%] had single valve replacement: MVR 118, AVR 8 and TVR 3; 33[20.3%] had double valve replacement: MVR+AVR 27 and MVR+TVR 6; and a single case had triple valve replacement. Other surgical procedures were added in 34 patients. The operative mortality rate within 30 days of surgery was 6.1%, and it was, however, 4.2%, with single MVR. Late mortality rate was 6.7% or 1.95%/patient-year of a linealized mortality rate. Early survivors of 153 patients were followed up for a total of 565.1 patient-years [a mean of 44.3*27.1 months]. The linealized annual complication rates were: 1.95% emboli/patient-year, 0.89% bleeding/patient-year 1.24% endocarditis/patient-year, and 4.25% overall failure/patient-year. Primary tissue failure occurred at a rate of 1.59%/patient-year. The actuarial survival rates including operative mortality were 87.0*4.1% and 77.3*6.6% at 5 and 11 years after surgery respectively. The probability of freedom from thromboembolic complication of 89.2*3.4% at 5 years after surgery lasted unchanged upto 11 years. The probability of freedom from overall valve failure was 81.3*4.5% at postoperative 5 years, and it dropped down to 26.2*19.4% at 11 years, although the latter was statistically insignificant because of a small number of patients entering into the years approaching the follow-up end. However, the probability of freedom from the primary tissue failure was 81.3*10.6% at postoperative 9 years, which coincides closely with the speculated rate of tissue degeneration of about 20% in 10 years. These clinical results confirm the low thrombogenicity of the Hancock porcine valve and the reasonable failure rate of tissue degeneration.