Properties of hydroxyapatite synthesize by wet chemical method

S. Ramesh,S. Adzila,C.K.L. Jeffrey,C.Y. Tan,J. Purbolaksono,A.M. Noor,M.A. Hassan,I. Sopyan,W.D. Teng 한양대학교 세라믹연구소 2013 Journal of Ceramic Processing Research Vol.14 No.4

The sintering behavior of a commercial HA and synthesized HA was investigated over the temperature range of 700 o C to 1400 o C in terms of phase stability, bulk density, Young’s modulus and Vickers hardness. In the present research, a wet chemical precipitation reaction was successfully employed to synthesize a submicron, highly crystalline, high purity and single phase stoichiometric HA powder that is highly sinteractive particularly at low temperature regimes below 1100 o C. It has been revealed that the sinterability of the synthesized HA was significantly greater than that of the commercial HA. The temperature for the onset of sintering and the temperature required to achieve densities above 98% of theoretical value were approximately 150 o C lower for the synthesized HA than the equivalent commercial HA. Nevertheless, decomposition of HA phase upon sintering was not observed in the present work for both powders.

Strength loss contributions during stages of heating, retention and cooling regimes for concretes

Yaragal, Subhash C.,Warrier, Jishnu,Podila, Ramesh Techno-Press 2015 Advances in materials research Vol.4 No.1

Concrete suffers strength loss when subjected to elevated temperatures during an accidental event such as fire. The loss in strength of concrete is mainly attributed to decomposition of C-S-H gel and release of chemically bound water, which begins when the temperature exceeds $500^{\circ}C$. But it is unclear about how much strength loss occurs in different stages of heating, retention and cooling regimes. This work is carried out to separate the total strength loss into losses during different stages of heating, retention and cooling. Tests were carried out on both Ordinary Portland Cement (OPC) based concrete and Ground Granulated Blast Furnace Slag (GGBFS) blended concrete for $200^{\circ}C$, $400^{\circ}C$, $600^{\circ}C$ and $800^{\circ}C$ with a retention period of 1 hour for each of these temperature levels. Furnace cooling was adopted throughout the experiment. This study reports strength loss contribution during heating, retention and cooling regimes for both OPC based and GGBFS based concretes.

Principal Component Analysis and Molecular Characterization of Reniform Nematode Populations in Alabama

Seloame T. Nyaku,Ramesh V. Kantety,Ernst Cebert,Kathy S. Lawrence,Joseph O. Honger,Govind C. Sharma 한국식물병리학회 2016 Plant Pathology Journal Vol.32 No.2

U.S. cotton production is suffering from the yield losscaused by the reniform nematode (RN), Rotylenchulusreniformis. Management of this devastating pest is ofutmost importance because, no upland cotton cultivarexhibits adequate resistance to RN. Nine populationsof RN from distinct regions in Alabama and onepopulation from Mississippi were studied and thirteenmorphometric features were measured on 20 male and20 female nematodes from each population. Highly correlatedvariables (positive) in female and male RN morphometricparameters were observed for body length(L) and distance of vulva from the lip region (V) (r = 0.7)and tail length (TL) and c’ (r = 0.8), respectively. Thefirst and second principal components for the femaleand male populations showed distinct clustering intothree groups. These results show pattern of sub-groupswithin the RN populations in Alabama. A one-wayANOVA on female and male RN populations showedsignificant differences (p ≤ 0.05) among the variables.Multiple sequence alignment (MSA) of 18S rRNA sequences(421) showed lengths of 653 bp. Sites within thealigned sequences were conserved (53%), parsimonyinformative(17%), singletons (28%), and indels (2%),respectively. Neighbor-Joining analysis showed intraand inter-nematodal variations within the populationsas clone sequences from different nematodes irrespectiveof the sex of nematode isolate clustered together. Morphologically, the three groups (I, II and III) couldnot be distinctly associated with the molecular datafrom the 18S rRNA sequences. The three groups maybe identified as being non-geographically contiguous.

Principal Component Analysis and Molecular Characterization of Reniform Nematode Populations in Alabama

Nyaku, Seloame T.,Kantety, Ramesh V.,Cebert, Ernst,Lawrence, Kathy S.,Honger, Joseph O.,Sharma, Govind C. The Korean Society of Plant Pathology 2016 Plant Pathology Journal Vol.32 No.2

U.S. cotton production is suffering from the yield loss caused by the reniform nematode (RN), Rotylenchulus reniformis. Management of this devastating pest is of utmost importance because, no upland cotton cultivar exhibits adequate resistance to RN. Nine populations of RN from distinct regions in Alabama and one population from Mississippi were studied and thirteen morphometric features were measured on 20 male and 20 female nematodes from each population. Highly correlated variables (positive) in female and male RN morphometric parameters were observed for body length (L) and distance of vulva from the lip region (V) (r = 0.7) and tail length (TL) and c' (r = 0.8), respectively. The first and second principal components for the female and male populations showed distinct clustering into three groups. These results show pattern of sub-groups within the RN populations in Alabama. A one-way ANOVA on female and male RN populations showed significant differences ($p{\leq}0.05$) among the variables. Multiple sequence alignment (MSA) of 18S rRNA sequences (421) showed lengths of 653 bp. Sites within the aligned sequences were conserved (53%), parsimony-informative (17%), singletons (28%), and indels (2%), respectively. Neighbor-Joining analysis showed intra and inter-nematodal variations within the populations as clone sequences from different nematodes irrespective of the sex of nematode isolate clustered together. Morphologically, the three groups (I, II and III) could not be distinctly associated with the molecular data from the 18S rRNA sequences. The three groups may be identified as being non-geographically contiguous.

Identification of Superior Polyvoltine Hybrids (polyvoltine x bivoltine), of Silkworm, Bombyx mori L.

C. G. P. Rao,Chandrashekharaiah,K. Ibrahim Basha,S. V. Seshagiri,C. Ramesh,H. Nagaraju 한국잠사학회 2004 International Journal of Industrial Entomology Vol.8 No.1

Ten promising polyvoltine mulberry silkworm strains (SDMG1, SDMG2, SDMG3, SDMG4, SDMW1, SDMW2, RMW1, RMW2, RMW3 and RMW4) that are superior in quantitative and qualitative traits have been synthesized in the polyvoltine breeding laboratory of Andhra Pradesh State Sericulture Research & Development Institute, Hindupur through systematic hybridization and appropriate selection methods. After the genotypes were found homozygous for the desired traits, they have been crossed with 3 bivoltine testers (APS8, APS4 and NB4D2) and thirty new hybrid combinations were developed for the assessment of their hybrid performance. Phenotypic expressions of economically important quantitative and qualitative traits of fist filial generation were measured and subjected for statistical analysis. Evaluation Index and Subordinate Function methods were employed for the assessment of hybrid performance since they are widely used in silkworm hybrid evaluation. Total of seven poly ´ bivoltine combinations, which ranked high in both the methods, were selected as potential combinations for further field test. These combinations also ranked significantly higher than the control hybrid (APM1 ´ APS8).

Performance and emission characteristics of a low heat rejection spark ignited engine fuelled with E20

C. Ramesh Kumar,G. Nagarajan 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.4

In internal combustion engines, the concept of low heat rejection (LHR) using thermal barrier coating on the surface of combustion chamber is gaining attention. Thermal barrier coating reduces the heat transfer to the cooling system, protects engine components from peak heat flux and fluctuating temperature produced during combustion and improves the performance of the engine. Information in the literature is plentiful for LHR diesel engine and only few studies exist on LHR spark ignited engine. The application of thermal barrier coating in spark ignited engine is limited by pre-ignition and knocking due to elevated combustion chamber temperature. A spark ignited engine with moderate insulation on the combustion chamber and higher octane fuel can overcome this difficulty. The objective of the present experimental study is to quantify the changes in performance and emission characteristics brought by partial thermal insulation on the combustion chamber of a four stroke spark ignited engine fueled with E20 blend. Partial thermal insulation was created by coating 0.3 mm thick Alumina (Al2O3) on the cylinder head, inlet and exhaust valves. The changes are quantified with respect to unmodified engine fueled with gasoline. The combustion parameters such as flame development and rapid burn duration are also estimated and compared. The results indicate that partially insulated SI engine when fueled with E20 improves performance and reduces emission. A maximum of 48% reduction in THC and 50% reduction in CO emission at part load was achieved.

Impact of heat treatment on mechanical and tribological properties of metal matrix composites of AA6082 T6 with Tin, Zinc and graphite

C. Ramesh,Mohanraj Chandran,K. Chellamuthu,A. Sivakumar 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.1

In this research article, the metal matrix composite with AA6082 was formed with mono Tin (5 wt%), Zinc (5 wt%), graphite(5 wt%) and hybrid. The solution heat treatment process and quenching with water and solidification were carried out andresults were compared with AA6082 T6. The different analysis includes mechanical properties (Tensile strength, microhardness), metallurgical properties (SEM and EDX) and tribological property (friction and wear). Micro structure of heattreated AA6082 MMC found with lower defects and fine grain size. Hardness values of heat treated AA6082+Zinc(A6) andhybrid AA6082(A8) found higher than AA6082 T6. The ultimate tensile strength of heat treated AA6082+Zinc(A6) and hybridAA6082(A8) observed higher than AA6082 T6. The wear and friction rate also reduced with heat treated AA6082+Zinc andAA6082 hybrid metal matrix composites.

Low-temperature sintering and prolonged holding time on the densification and properties of zirconia ceramic

C.H. Ting,S. Ramesh,C.Y. Tan,N.I. Zainal Abidin,W.D. Teng,I. Urriés,L.T. Bang 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.8

In the present work, the effect of low temperature sintering, focusing on varying the sintering holding times on the mechanicalproperties, microstructure and low temperature degradation behavior of undoped and MnO2-doped Y-TZP ceramics wereinvestigated. Green samples were sintered at temperatures ranging from 1100 to 1250 oC at varying holding times rangingfrom 12 min. to 480 min. The sintered bodies were characterized in terms of bulk density, Vickers hardness, fracturetoughness, phase stability and grain size. The results indicated that the relative density of above 95%, Vickers hardness of 14GPa and fracture toughness of 5 MPam1/2 were obtained when sintered at lower sintering temperature (below 1250 oC) andlonger sintering times for MnO2-doped Y-TZP samples. Grain growth was marginal and the average grain size of all samplesranged between 0.14 and 0.28 µm. The results indicated that the grain growth kinetics was influenced mainly by the sinteringtemperature and not by the sintering holding time. The addition of MnO2 was found to be beneficial in enhancing densificationand mechanical properties of Y-TZP particularly at low sintering temperature of 1100 oC and low holding time of 12 min. Thelow-temperature degradation experiment conducted in superheated steam indicated that all the samples did not transformedto the monoclinic symmetry, attributed mainly to the lower grain size sintered at relatively low sintering temperatures

Effect of Dietary Blueberry Pomace on Selected Metabolic Factors Associated with High Fructose Feeding in Growing Sprague–Dawley Rats

Ramesh C. Khanal,Luke R. Howard,Samuel E. Wilkes,Theodore J. Rogers,Ronald L. Prior 한국식품영양과학회 2012 Journal of medicinal food Vol.15 No.9

An experiment was conducted to study the protective effect of feeding extruded and unextruded blueberry pomace (BBP) on selected metabolic parameters associated with metabolic syndrome in a model of high fructose (HF)-fed growing Sprague–Dawley rats. Treatments were as follows: (1) control (modified AIN-based diet); (2) HF diet (AIN diet with 58% fructose); (3) HF diet with 1.5% unextruded BBP; (4) HF diet with 1.5% extruded BBP; (5) HF diet with 3% unextruded BBP; and (6) HF diet with 3% extruded BBP. Compared with the control, HF feeding increased fasting plasma insulin and fasting and postprandial plasma triglycerides as well as homeostatic scores of insulin resistance and β-cell function, but not weight gain, diet intake and efficiency, abdominal fat, oral glucose tolerance, and fasting and postprandial plasma glucose, cholesterol, and leptin levels. Inclusion of unextruded or extruded BBP was effective in minimizing or ameliorating the fructose-induced metabolic anomalies, except postprandial plasma triglycerides, especially at 3% of the diet. In addition, unextruded or extruded BBP at 3% of the diet was also able to reduce plasma cholesterol and abdominal fat relative to the HF control, which may impart additional health benefits. Compared with the control, inclusion of unextruded or extruded BBP at both 1.5% and 3% resulted in lower total fat weight, and animals fed a diet supplemented with 3% unextruded BBP in fasting state or 3% unextruded BBP in fed state had lower leptin levels than the control. This is the first study demonstrating the beneficial effects of feeding blueberry pomace on health.

Effect of Feeding Grape Pomace on Selected Metabolic Parameters Associated with High Fructose Feeding in Growing Sprague–Dawley Rats

Ramesh C. Khanal,Luke R. Howard,Theodore J. Rogers,Samuel E. Wilkes,Ishwori B. Dhakal,Ronald L. Prior 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.12

The effect of feeding grape pomace on certain metabolic parameters associated with high fructose (HF)feeding was studied. Forty male growing Sprague–Dawley rats were randomly assigned into groups: (1) control; (2) HF; (3)HF with low-level (1.5% of diet) grape pomace (HF + LP), and (4) HF with high-level (5.0% of diet) grape pomace (HF + HP). The HF + LP and HF + HP diets provided 115 and 218 mg of procyanidins/kg, respectively. Compared with the controls, HFfed animals consumed less and were smaller, whereas animals in the HF + LP and HF + HP groups were in between. A similar trend was observed for abdominal fat and abdominal fat as a percentage of body weight. No change in heart or kidney weight occurred. Liver weight as a percentage of body weight was higher for animals when fructose was included in the diet compared with those on control diet, and inclusion of grape pomace had no effect. Fasting plasma glucose, insulin, and triglyceride levels tended to be higher in animals fed HF diet, and grape pomace reduced their levels to values similar to the control animals. Compared with control animals, HF-fed animals had higher weekly postprandial plasma triglycerides, which were reduced by feeding grape pomace, but no change in plasma cholesterol was observed. Glucose intolerance was observed in animals fed HF diet and was accompanied by a 25% increase in homeostatic model assessment (HOMA) of insulin resistance. Inclusion of grape pomace increased glucose tolerance and insulin sensitivity. No significant change (P > .1) in HOMA of β-cell function or Quantitative Insulin-Sensitivity Check Index was observed. Overall, HF diet did not produce as strong a response of metabolic syndrome as has been shown in the literature. The inclusion of grape pomace in the diet was effective in modulating some aspects of metabolic parameters associated with metabolic syndrome, and the higher level of grape pomace in the diet produced a slightly better response than the lower level.