Interspecific Hybrids from Wild x Cultivated Triticum Crosses - A Study on the Cytological Behaviour and Molecular Relations

Kari Bhagyalakshmi,Mahadevan Kumar,Samudrakani Arumugachamy,Amala Joseph,Thondikulam Subramanian Raveendran,Kunnummal Kurungara Vinod 한국작물학회 2008 Journal of crop science and biotechnology Vol.11 No.4

Genetic diversity of cultivated wheat is narrowing down and is increasingly becoming non-complacent in tackling new pathogenic races and adverse environmental situations. Wild relatives of wheat are rich repositories of beneficial genes that are capable of defying adverse situations. However, these wild species are not readily crossable with cultivated ones. The present study attempted to cross three wild wheat species as females with three cultivated species of varying ploidy to understand the intricate behaviour of hybrids in relation to cytology, morphology, and molecular recombination. Post-fertilization barriers caused hybrid recovery in wild species in contrast to cultivated species. Triticum monococcum did not produce hybrids in any of the crosses. Various degrees of chromosome anomalies and hybrid sterility were seen with hybrids of T. timopheevi and T. sphaerococcum. Cytoplasmic factors were suspected to add more to the abnormality. G genome from T. timopheevi could enhance more pairing between B and D of cultivated species. Precocity of certain chromosomes in laggard formation was evident, pointing towards evolutionary self balance of the genomes which prevented homeologous pairing. They are eliminated in hybrids. Molecular diversity clearly corroborated with genetic proximity of the species, which distinguished themselves by maintaining the genome homeology. Genetic diversity of cultivated wheat is narrowing down and is increasingly becoming non-complacent in tackling new pathogenic races and adverse environmental situations. Wild relatives of wheat are rich repositories of beneficial genes that are capable of defying adverse situations. However, these wild species are not readily crossable with cultivated ones. The present study attempted to cross three wild wheat species as females with three cultivated species of varying ploidy to understand the intricate behaviour of hybrids in relation to cytology, morphology, and molecular recombination. Post-fertilization barriers caused hybrid recovery in wild species in contrast to cultivated species. Triticum monococcum did not produce hybrids in any of the crosses. Various degrees of chromosome anomalies and hybrid sterility were seen with hybrids of T. timopheevi and T. sphaerococcum. Cytoplasmic factors were suspected to add more to the abnormality. G genome from T. timopheevi could enhance more pairing between B and D of cultivated species. Precocity of certain chromosomes in laggard formation was evident, pointing towards evolutionary self balance of the genomes which prevented homeologous pairing. They are eliminated in hybrids. Molecular diversity clearly corroborated with genetic proximity of the species, which distinguished themselves by maintaining the genome homeology.

A Novel Quadrant Search Based Mitigation Technique for DC Voltage Fluctuations in Multilevel Inverters

Roseline, Johnson Anitha,Vijayenthiran, Subramanian,V., Rajini,Mahadevan, Senthil Kumaran The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.3

The hybrid cascaded multilevel inverter (HCMLI) is a popular converter topology that is being increasingly used in high power medium voltage drives. The intricacy of the control technique for a HCMLI increases with the number of levels and due to fluctuating dc voltages. This paper presents a novel offline quadrant search based space vector modulation technique to synthesize a sinusoidal output from a dispersed pattern of voltage vectors due to different voltages in the auxiliary unit. Such an investigation has never been reported in the literature and it is being attempted for the first time. The method suggested distributes the voltage vectors for a reduced total harmonic distortion at minimal computation. In addition, the proposed algorithm determines the maximum modulation index in the linear modulation range in order to synthesize a sinusoidal output for both normal and abnormal vector patterns. It is better suited for a wide range of practical applications. It is particularly well suited for renewable source fed inverters which utilize large capacitor banks to maintain the dc link, which are prone to such slow fluctuations. The proposed quadrant search space vector modulation technique is simulated using MATLAB/SIMULINK and implemented using a Nexys-2 Spartan-3E FPGA for a developed prototype.

New mass optimization technique to achieve low mass BIW designs using optimal material layout methodology on the frontal vehicle crash

Rajasekaran Mohan,, Hariram Venkatesan,Subramanian Mahadevan 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.12

BIW is the car body made of sheet metals welded together. Numerous researches were performed across the world to optimize and save mass on the car body design. This paper describes the new methodology which can be used to reduce mass of the BIW in a full frontal rigid wall impact crash model. The new methodology of identifying materials for the BIW components has been presented. Frontal crash load case has been considered for the research. Since Frontal impact is an evaluation to predict only the frontal performance, parts in the front impact load path like dash, A-pillar, reinforcements and hinge pillar region has been considered as the design space for the material layout optimization. List of materials have been provided as a variable for a list of parts in the BIW and DOE sampling were generated. Response for the DOE designs results have been extracted to study the sensitivity of the parts for the frontal load case and design performance was analysed. Subsequent multi-objective optimization have been performed based on the DOE results, to achieve an optimal material selection for each of the parts in the design space. Further performance improving techniques considering the sensitivity chart have been explored and optimal design with low mass and improved frontal crash performance have been achieved and presented. The use of this methodology on a full vehicle crash model has achieved 15.4 % mass saving with the performance better than the baseline design.

New methodology for light weight solutions to improve BIW structural performance using bulk head optimization

Rajasekaran Mohan,, Hariram Venkatesan,Subramanian Mahadevan 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.8

Body-in-white (BIW) is the Car body with welded sheet metal parts painted in white. Automobile companies were trying to optimize mass and improve performance with optimal mass addition. In many automotive industries many BIW designs due to aggressive mass optimization, there is a need to have smart solutions to improve BIW structure performance with very little mass increase. In this paper, a new technique of identifying the optimized internal reinforcements in the BIW at conceptual BIW design phase using Deign of experiments and Multi-objective optimization has been investigated. The paper focus on the Bending and torsion stiffness load cases to evaluate the BIW performance. Bulk head designs were designed at the major joints like A-pillar, B-pillar, C-pillar and rocker and their optimal locations to improve stiffness with minimum mass increase were identified using Design of experiments and multi objective techniques. The research shows that the optimized Bulk head design locations using the DOE technique has improved the overall BIW stiffness performance by 3.9% with 1.2% of mass addition in the BIW.

A Novel Quadrant Search Based Mitigation Technique for DC Voltage Fluctuations in Multilevel Inverters

Johnson Anitha Roseline,Subramanian Vijayenthiran,Rajini V,Senthil Kumaran Mahadevan 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.3

The hybrid cascaded multilevel inverter (HCMLI) is a popular converter topology that is being increasingly used in high power medium voltage drives. The intricacy of the control technique for a HCMLI increases with the number of levels and due to fluctuating dc voltages. This paper presents a novel offline quadrant search based space vector modulation technique to synthesize a sinusoidal output from a dispersed pattern of voltage vectors due to different voltages in the auxiliary unit. Such an investigation has never been reported in the literature and it is being attempted for the first time. The method suggested distributes the voltage vectors for a reduced total harmonic distortion at minimal computation. In addition, the proposed algorithm determines the maximum modulation index in the linear modulation range in order to synthesize a sinusoidal output for both normal and abnormal vector patterns. It is better suited for a wide range of practical applications. It is particularly well suited for renewable source fed inverters which utilize large capacitor banks to maintain the dc link, which are prone to such slow fluctuations. The proposed quadrant search space vector modulation technique is simulated using MATLAB/SIMULINK and implemented using a Nexys-2 Spartan-3E FPGA for a developed prototype.

Interspecific Hybrids from Wild $\times$ Cultivated Triticum Crosses - A Study on the Cytological Behaviour and Molecular Relations -

Bhagyalakshmi, Kari,Vinod, Kunnummal Kurungara,Kumar, Mahadevan,Arumugachamy, Samudrakani,Prabhakaran, Amala Joseph,Raveendran, Thondikulam Subramanian The Korean Society of Crop Science 2008 Journal of crop science and biotechnology Vol.11 No.4

Genetic diversity of cultivated wheat is narrowing down and is increasingly becoming non-complacent in tackling new pathogenic races and adverse environmental situations. Wild relatives of wheat are rich repositories of beneficial genes that are capable of defying adverse situations. However, these wild species are not readily crossable with cultivated ones. The present study attempted to cross three wild wheat species as females with three cultivated species of varying ploidy to understand the intricate behaviour of hybrids in relation to cytology, morphology, and molecular recombination. Post-fertilization barriers caused hybrid recovery in wild species in contrast to cultivated species. Triticum monococcum did not produce hybrids in any of the crosses. Various degrees of chromosome anomalies and hybrid sterility were seen with hybrids of T. timopheevi and T. sphaerococcum. Cytoplasmic factors were suspected to add more to the abnormality. G genome from T. timopheevi could enhance more pairing between Band D of cultivated species. Precocity of certain chromosomes in laggard formation was evident, pointing towards evolutionary self balance of the genomes which prevented homeologous pairing. They are eliminated in hybrids. Molecular diversity clearly corroborated with genetic proximity of the species, which distinguished themselves by maintaining the genome homeology.