Yamamoto K.,Kurume National College of Technology |
Inthidech S.,Mahasarakam University |
Sasaguri N.,Mahasarakam University |
Matsubara Y.,Fukuoka Jo Gakuin University
Materials Transactions | Year: 2014
The influence of Mo and Waddition on the high temperature hardness of M7C3carbide was investigated using unidirectionally solidified hypereutectic cast iron with 25 mass%Cr. Concentrations of alloying elements in primary M7C3 carbide were measured by EDS. As Mo or W content of the cast iron increases, the concentration of Mo and Win the carbide increased and that of Fe decreased. However, the Cr content was almost the same as about 60 mass% in spite of increasing the Mo and W contents. It was found from the XRD results that the lattice constant of M7C 3 carbide changed and its attendant volume of a unit cell increased as the Mo or W content was increased. From this point of view, it can be considered that Fe atoms in the M7C3 carbide were substituted by Mo or W which has larger atomic radius than Fe. In all the specimens, the hardness of M7C3 carbides are about 1600HV0.3 at the room temperature, and it decreases gradually with a rise of the test temperature. The decreasing ratio of carbide hardness becomes smaller at high temperature as the Mo or W concentration in M7C3 carbide increases. Thus, the dissolution of Mo or W atom into M 7C3 carbide is very effective to maintaining the high temperature hardness of carbide. However, the increment of the hardness became smaller at higher Mo and W contents, so that an excess addition of both elements gave less effect than expected. The fracture toughness of M7C 3 carbide at the room temperature was measured using an indentation fracture method, and the values were very similar among the carbides regardless of Mo and W concentration in the M7C3 carbide. © 2014 The Japan Institute of Metals and Materials.
Simla S.,Mahasarakam University |
Boontang S.,Mahasarakam University |
Harakotr B.,Thammasat University
Australian Journal of Crop Science | Year: 2016
The use of corn wastes should increase production efficiency. The objective of this study was to evaluate anthocyanin content, phenolic content and antioxidant activity in kernel, cob, silk, and husk of purple waxy corn. Three varieties of purple waxy corn and a commercial check were planted in a randomized complete block design with three replications. Data were recorded for anthocyanin content, anthocyanin yield, phenolic content and antioxidant activity determined by 2,2-diphenyl-1-picrylhydrazyl radical scavenging ability (DPPH) and Trolox equivalent antioxidant capacity (TEAC) methods at edible stage (20 days after pollination; DAP) and seed stage (35 DAP). Significant differences between kernel maturity stages and among corn varieties and ear components were observed. Seed stage had significantly higher anthocyanin content, phenolic content and antioxidant activity than edible stage. KKU-OP and commercial check had the highest anthocyanin content, anthocyanin yield, DPPH and TEAC at edible and seed maturity stages. Corn silk had high anthocyanin content, DPPH and TEAC at seed stage, but corn cob had the highest anthocyanin content per unit of area. KKU-OP had the highest anthocyanin content, DPPH and TEAC at both maturity stages, whereas KKU-OP and KKU-WX111031 had the highest anthocyanin yield at edible and seed stages, respectively. Corn silk and corn cob had anthocyanins and can be used as a source of anthocyanins in food industry. KKU-OP and KKU-WX111031 had high anthocyanins and antioxidant activity and could be used as an alternative source of bioactive compounds for the functional food industry and a germplasm source for high anthocyanins.
Petjul K.,Rajamangala University of Technology at Tawan-ok |
Sangdee A.,Mahasarakam University |
Thaewnon-Ngiw B.,Mahasarakam University
OnLine Journal of Biological Sciences | Year: 2011
Problem statement: The genetic diversity of Barbodes species in Thailand is presently unavailable. The objectives of this study were to study external morphology and genetic diversity using Randomly Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) of three Barbodes species; Barbodes altus, B. gonionotus and Barbodes sp. Approach: Two of twelve screened decanucleotide primers (OPA07 and UBC122), were selected for the genetic analysis of Barbodes genera. Results: Thirty-five reproducible and polymorphic fragments (250-2150 bp in length) were generated across the investigated species. The percentages of polymorphic band were 7.69, 3.85 and 6.25% for B. altus, B. gonionotus and Barbodes sp., respectively. The UPGMA indicated a similarity coefficient between B. gonionotus and Barbodes sp. up to 90%. The candidate species-specific marker of UBC122 primer was found in only Barbodes sp. Conclusion: This approach indicates that Barbodes sp. may be a variant species of B. gonionotus. © 2011 Science Publications.