Development of Analytical Models for Switched Reluctance Machine and their Validation

Jayapragash, R.,Chellamuthu, C. The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

This paper presents analysis of Switched Reluctance Machine (SRM) using Geometry Based Analytical Model (GBAM), Finite Element Analysis (FEA) and Fourier Series Model (FSM) with curve fitting technique. Further a Transient Analysis (TA) technique is proposed to corroborate the analysis. The main aim of this paper is to give in depth procedure in developing a Geometry Based Analytical Model of Switched Reluctance Machine which is very accurate and simple. The GBAM is developed for the specifications obtained from the manufacturer and magnetizing characteristic of the material used for the construction. Precise values of the parameters like Magneto Motive Force (MMF), flux linkage, inductance and torque are obtained for various rotor positions taking into account the Fringing Effect (FE). The FEA model is developed using MagNet7.1.1 for the same machine geometry used in GBAM and the results are compared with GBAM. Further another analytical model called Fourier Series Model is developed to justify the accuracy of the results obtained by the methods GBAM and FEA model. A prototype of microcontroller based SRM drive system is constructed for validating the analysis and the results are reported.

A Novel Method to Optimize Nitrogen Requirements of Drip Fertigated Sugarcane

Hemalatha Swaminathan,Chellamuthu S 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Anatomic reconstruction for acromioclavicular joint injuries: a pilot study of a cost-effective new technique

Radhakrishnan Pattu,Girinivasan Chellamuthu,Kumar Sellappan,Chendrayan Kamalanathan 대한견주관절의학회 2021 대한견주관절의학회지 Vol.24 No.4

Background: The treatment for acromioclavicular joint injuries (ACJI) ranges from a conservative approach to extensive surgical reconstruction, and the decision on how to manage these injuries depends on the grade of acromioclavicular (AC) joint separation, resources, and skill availability. After a thorough review of the literature, the researchers adopted a simple cost-effective technique of AC joint reconstruction for acute ACJI requiring surgery. Methods: This was a prospective single-center study conducted between April 2017 and April 2018. For patients with acute ACJI more than Rockwood grade 3, the researchers performed open coracoclavicular ligament reconstruction using synthetic sutures along with an Endobutton and a figure of 8 button plate. This was followed by AC ligament repair augmenting it with temporary percutaneous AC K-wires. Clinical outcomes were evaluated using the Constant Murley shoulder score. Results: Seventeen patients underwent surgery. The immediate postoperative radiograph showed an anatomical reduction of the AC joint dislocation in all patients. During follow-up, one patient developed subluxation but was asymptomatic. The mean follow-up period was 30 months (range, 24–35 months). The mean Constant score at 24 months was 95. No AC joint degeneration was noted in follow-up X-rays. The follow-up X-rays showed significant infra-clavicular calcification in 11 of the 17 patients, which was an evidence of a healed coracoclavicular ligament post-surgery. Conclusions: This study presents a simple cost-effective technique with a short learning curve for anatomic reconstruction of acute ACJI. The preliminary results have been very encouraging.

High temperature extensional rheology of commercially available polycarbonate mixed with flame retardant salts

Samrat Sur,Manojkumar Chellamuthu,Jonathan Rothstein 한국유변학회 2020 Korea-Australia rheology journal Vol.32 No.1

In this paper, we present a study of the dripping properties of polycarbonate (PC) modified with combinations of earth metal salts of inorganic sulfur, potassium perfluorobutane sulfonate (Rimar); non-halogenated flame retardant additives, potassium diphenyl sulfone-3-Sulfonate (KSS); and block co-polymerspolytetrafluoroethylene encapsulated with styrene acrylonitrile resin (T-SAN). Measurements of the extensional rheology of polycarbonate with different concentration of each flame retardant additive were performed using a custom-built high temperature Capillary Breakup Extensional Rheometer (CaBER) at temperatures up to T = 400oC. From these measurements, the evolution of the apparent transient extensional viscosity was monitored as a function of time and strain both in air and in an inert nitrogen environment. The evolution of extensional viscosity has been shown to be an excellent tool for predicting the dripping behavior of polymers exposed to heat and a valuable tool for understanding the mechanism of polymer degradation which is typically dominated by either crosslinking or charring. We show that extensional rheology measurements are significantly more sensitive to temperature-induced changes to the polymer microstructure than shear rheology measurements. We have also performed systematic concentration of specific flame retardant salts and through variation in extensional rheology and investigated the optimum concentration required to achieve a V0 rating. Finally, we will show that extensional rheology is a powerful method for predicting the effect of flame retardant modifiers and optimizing their use in new flame resistant materials.

Total elbow arthroplasty for active primary tuberculosis of the elbow: a curious case of misdiagnosis

Radhakrishnan Pattu,Girinivasan Chellamuthu,Kumar Sellappan,Kamalanathan Chendrayan 대한견주관절학회 2022 대한견주관절의학회지 Vol.25 No.2

The incidence of musculoskeletal tuberculosis (TB) is on the rise due to the current Acquired Immunodeficiency Syndrome (AIDS) pandemic. Spine is the most common osseous site, followed by other joints. TB identified in the elbow accounts for 2%–5% of skeletal TB cases, which are secondary to pulmonary TB. Primary elbow TB is rare. We report a case of primary TB of the elbow which had a negative synovial biopsy. A 46-year-old right-hand dominant female patient with chronic pain and disability of the right elbow was diagnosed with chronic non-specific arthritis based on an arthroscopic synovial biopsy. The case was diagnosed retrospectively as active TB from bone cuts post total elbow arthroplasty. Anti-tuberculosis treatment (ATT) was given postoperatively for 12 months. The patient reported good functional outcomes at 3 years of follow-up. Such atypical presentations of osteoarticular TB are challenging to diagnose. Therefore, particularly in endemic areas, clinicians should be careful before excluding such a diagnosis even after a negative biopsy. Further research should investigate whether active TB of small joints such as the elbow can be treated with ATT, and early arthroplasty should be a focus of this research.

Development of Analytical Models for Switched Reluctance Machine and their Validation

R. Jayapragash,C. Chellamuthu 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

This paper presents analysis of Switched Reluctance Machine (SRM) using Geometry Based Analytical Model (GBAM), Finite Element Analysis (FEA) and Fourier Series Model (FSM) with curve fitting technique. Further a Transient Analysis (TA) technique is proposed to corroborate the analysis. The main aim of this paper is to give in depth procedure in developing a Geometry Based Analytical Model of Switched Reluctance Machine which is very accurate and simple. The GBAM is developed for the specifications obtained from the manufacturer and magnetizing characteristic of the material used for the construction. Precise values of the parameters like Magneto Motive Force (MMF), flux linkage, inductance and torque are obtained for various rotor positions taking into account the Fringing Effect (FE). The FEA model is developed using MagNet7.1.1 for the same machine geometry used in GBAM and the results are compared with GBAM. Further another analytical model called Fourier Series Model is developed to justify the accuracy of the results obtained by the methods GBAM and FEA model. A prototype of microcontroller based SRM drive system is constructed for validating the analysis and the results are reported.

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.