129 research outputs found
Effect of roughness, microstructure, and chemistry on the environmental durability of structural alloys
Get PDFUnlike functional materials where one design property is usually optimized, structural materials need to meet several design requirements including but not limited to excellent mechanical properties and environmental tolerance. However, more often than not, the metallurgical principles used to improve mechanical properties result in a decrease in the environmental tolerance. Though it is difficult to design materials that can thrive in extreme environments like high temperature, high pressure, and harsh chemicals, these conditions are often where the biggest scientific and economic opportunities lie. Aeroengines, and oil refineries are two example applications that encounter these issues. This study specifically focusses on improving the environmental tolerance of NiCrAl films a common bond coat used in aeroengines, and ferrous alloys used in petroleum production. The goal was to develop solutions that improve the environmental tolerance while minimally affecting other properties of these alloys.
The oxidation behavior of a model sputtered NiCrAl system was studied in various time and oxygen partial pressure (pO2) regimes. Low pO2 conditions seemed to favor the formation of protective oxides. However, tuning the composition of the base alloy was an effective way to limit the oxidation rate in high pO2 conditions. Thermal destabilization of the sputtered microstructure was found to take place on similar timescales to the transient oxide formation. Thus dilute Y additions were made to temporarily stabilize the sputtered microstructure and manipulate the transient stages of oxidation.
Yttrium addition not only retarded grain growth through nanoclustering and kinetically pinning grains, but also helped nucleate and grow dense, and slow-growing oxides. In some cases, the improvement in oxidation resistance via. Y addition was similar to reducing the pO2 by several orders of magnitude. Robust α-alumina oxides formed on Y doped NiCrAl films at temperatures as low as 900 oC by oxidation in an air environment which is unprecedented and could be of major commercial importance. An attempt was made to understand this anomalous oxidation behavior by using unconventional diffusion-triples comprising of a sputtered NiCr (undoped and Y doped) top layer, Al middle layer, and a sintered (micrograined) NiCr bottom layer. Annealing experiments conducted on the diffusion-triples proved that Al diffusion in sputtered NiCr is more rapid than that in sintered NiCr. Through the use of profile processing techniques, Al was shown to follow type B kinetics for grain boundary diffusion in sputtered NiCr. It also revealed that Y addition to sputtered NiCr further accelerates Al diffusion through a non-Fickian mechanism involving Al clustering.
The baseline fouling and corrosion behavior of ferrous alloys in a high temperature, high pressure, and an asphaltenic environment was also evaluated. Key insights were generated on the interplay between the thermochemical properties of the asphaltene, the environmental conditions, surface preparation of the alloys, and the chemistry of the deposits. X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy allowed for the first time to pinpoint mechanisms for high temperature model asphaltene deposition on ferrous alloys. Improving surface roughness alone was found to be a good strategy to mitigate asphaltenic fouling at lower temperatures where the asphaltene remains intact. However, at temperatures where reactive asphaltene decomposition products become present in solution, surface chemistry control becomes important. Specifically, a protective atomic layer deposition alumina chemistry on steels was found to significantly reduce asphaltenic fouling.
In order to evaluate whether a protective alumina chemistry could be generated on components with more complex geometries, low temperature pack cementation of ferrous alloys was conducted. Preliminary data did show an improvement in anti-fouling properties with both model asphaltenes in a static environment, as well as with crude oil in a hydrodynamic environment. However, XPS revealed a mixed alumina-hematite oxide on the surface that may be limiting the anti-fouling properties of these surfaces. Finally, new insights gained from developing low temperature pack cementation for ferrous alloys allowed for the modification of low thermal stability, functional metallic structures like Ni inverse opals. It resulted in a thermal stability enhancement by 500 oC, comparable to refractory metals in the same configuration. And also improved both the modulus and hardness of these structures.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-05-01The student, Pralav Shetty, accepted the attached license on 2019-02-20 at 15:57.The student, Pralav Shetty, submitted this Dissertation for approval on 2019-02-20 at 16:17.This Dissertation was approved for publication on 2019-02-22 at 10:53.DSpace SAF Submission Ingestion Package generated from Vireo submission #13398 on 2019-08-22 at 16:19:59Made available in DSpace on 2019-08-23T20:44:32Z (GMT). No. of bitstreams: 3
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Effect of beneficial microorganisms on nutrient profile of Moringa oleifera leaves.
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Trienzyme extraction and quantification of total folate from underutilized fruits.
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Suppression of N‑glycan processing enzymes by deoxynojirimycin in tomato (Solanum lycopersicum) fruit.
No full textThe present study investigated the potential of a small molecule inhibitor, 1-deoxynojirimycin (DNJ), to extend the shelf
life of tomatoes. The optimum concentration of DNJ and the proper ripening stage for treatment were standardized using
response surface methodology, following a central composite design. The concentration of DNJ used for the analysis was
0.15 mM, and 0.30 mM and the ripening stages of the tomato fruit analysed were immature green, mature green, breaker,
ripen and over-ripen. Analysis of the infuence of the DNJ treatment of the fruit using quadratic multiple regression models
considering the factors colour, texture, and free sugars revealed signifcant responses. A DNJ concentration of 0.30 mM and
fruit-ripening stage of mature green was found to be optimal for the treatment. DNJ-treatment maintained fruit frmness
throughout ripening with a signifcant reduction in reducing sugar formation. Enzyme activity of the N-glycan processing
enzymes involved in cell wall softening, α-mannosidase and β-d-N-acetylhexosaminidase revealed a signifcant reduction
in their activity by 2 and 3.5-fold, respectively. Down-regulation of expression of important ripening-related and softening
process-associated genes, aminocyclopropane carboxylic synthase-4, aminocyclopropane carboxylic oxidase, polygalacturonase and pectin methylesterases at 4, 5, 6 and 5-fold, respectively, was also observed. The present results showed that the
treatment of mature green tomato fruit with DNJ at a concentration of 0.30 mM can delay the ripening of the tomato fruit
by inhibiting cell wall and N-glycan processing enzymes
Review on Quantum Key Distribution
Get PDFThere have been tremendous developments in the field of cryptography. Quantum computers is one among them. Solving complex mathematical calculations are made easy using quantum computers. Introducing quantum physics into cryptography led to growth of quantum cryptography. Quantum cryptography is a technique of using photons to generate a cryptographic key and transmit it to a receiver using a suitable communication channel. Quantum cryptography uses quantum mechanical principles such as Heisenberg Uncertainty principle and photon polarisation principle to perform cryptographic tasks towards providing an effective security system. This study describes on to generate a key which is then converted into Quantum bits (Qubits) and send to the receiver securely
Chromium(III) and chromium(IV) bis(trimethylsilyl) amido complexes as ethylene polymerisation catalysts
No full textOxidation of Cr[N(SiMe3)(2)](2)(THF)(2) with iodine and dicumyl peroxide results in tetrahedral Cr(IV)Cr[N(SiMe3)(2)](2)I-2 and trigonal planar Cr(III) Cr[N(SiMe3)(2)](OCMe2Ph)(2), respectively; both complexes have been characterised by single-crystal X-ray diffraction, and both are active for ethylene polymerisation with alkylaluminium co-catalysts.PT: J; CR: AJJOU JAN, 1997, ORGANOMETALLICS, V16, P86 AJJOU JAN, 2000, J AM CHEM SOC, V122, P8968 ALONSO PJ, 2002, CHEM-EUR J, V8, P4056 BASI JS, 1971, J CHEM SOC A, P1433 BEAUDOIN MC, 2002, J MOL CATAL A-CHEM, V190, P159 BERNO P, 1994, ORGANOMETALLICS, V13, P1052 BLANCHARD H, 1988, J ORGANOMET CHEM, V341, P367 BOCHMANN M, 1980, J CHEM SOC DA, P1863 BRADLEY DC, 1972, J CHEM SOC CHEM COMM, P567 BRADLEY DC, 1976, ACCOUNTS CHEM RES, V9, P273 BRADLEY DC, 1978, INORG SYNTH, V18, P112 BRITOVSEK GJP, 1999, ANGEW CHEM INT EDIT, V38, P428 BURGER H, 1964, MONATSH, V95, P1099 CUMMINS CC, 1992, ANGEW CHEM INT EDIT, V31, P1501 CUMMINS CC, 1998, PROG INORG CHEM, V47, P685 DRYKACZ G, 1973, J AM CHEM SOC, V95, P4756 ELLER PG, 1977, COORDIN CHEM REV, V24, P1 FILIPPOU AC, 2002, EUR J INORG CHEM NOV, P2928 FILIPPOU AC, 2003, ANGEW CHEM INT EDIT, V42, P4486 FILIPPOU AC, 2003, ORGANOMETALLICS, V22, P3010 FIRMAN TK, 2001, J ORGANOMET CHEM, V635, P153 FRYZUK MD, 1995, ORGANOMETALLICS, V14, P5193 GIBSON VC, 1998, CHEM COMMUN 0821, P1651 GIBSON VC, 1999, J CHEM SOC DALT 0321, P827 GIBSON VC, 2000, J CHEM SOC DALTON, P1969 GIBSON VC, 2001, EUR J INORG CHEM JUL, P1895 GIBSON VC, 2002, J CHEM SOC DALTON, P4017 GIBSON VC, 2003, CHEM REV, V103, P283 HAGIHARA N, 1959, J AM CHEM SOC, V81, P3160 IKEDA H, 2001, MACROMOL CHEM PHYSIC, V202, P1806 IKEDA H, 2002, J ORGANOMET CHEM, V642, P156 KAYAL A, 2002, INORG CHEM, V41, P321 LAPLAZA CE, 1996, J AM CHEM SOC, V118, P8623 MESSERE R, 2000, EUR J INORG CHEM JUN, P1151 MINDIOLA DJ, 1998, ANGEW CHEM INT EDIT, V37, P945 MOWAT W, 1972, J CHEM SOC DA, P533 MOWAT W, 1973, J CHEM SOC DA, P770 ROBERTSON NJ, 2003, INORG CHEM, V42, P6876 SCHMID R, 2000, CAN J CHEM, V78, P265 SCHMID R, 2000, ORGANOMETALLICS, V19, P2756 SCHNEIDER S, 2001, INORG CHEM, V40, P4674 SCHULZKE C, 2002, ORGANOMETALLICS, V21, P3810 SCOTT SL, 2001, CHEM ENG SCI, V56, P4155 SEIDEL W, 1976, Z ANORG ALLG CHEM, V426, P150 SEIDEL W, 1976, Z ANORG ALLG CHEM, V426, P155 SMALL BL, 2004, MACROMOLECULES, V37, P4375 THEOPOLD KH, 1998, EUR J INORG CHEM JAN, P15 VANRENSBURG WJ, 2004, ORGANOMETALLICS, V23, P1207; NR: 48; TC: 3; J9: DALTON TRANS; PG: 3; GA: 865WTSource type: Electronic(1
Emvolio Instrument test reports and The ARRIVE guidelines 2.0 - Author checklist.pdf,
No full textThis also includes the details (1) test reports of Emvolio, as per the regulatory compliences (WHO/PQS/E003/TS01.1) and (2) Reports of Internal testing.
The file contains the ARRIVE2.0 Author Checklist for experiments carried out using rats.</p
Retraining displaced workers : what can developing countries learn from OECD nations?
Get PDFThe governments of most industrial countries provide financial support for adult training programs intended to retrain displaced workers. The author draws lessons from the experience of six industrial countries (Australia, Britain, Canada, Japan, Sweden, and the United States) on how to design and implement such retraining programs in low-income developing nations and middle-income countries. By retraining, the author means both improving job skills and remediating deficiencies in basic education. These are the lessons he emphasizes: Training programs should be independent of the educational system, with its rigid ties to degree requirements and academic schedules; links to employers must be developed and maintained so that trainees have marketable skills on completing the program. Training programs should be designed to minimize trainees'foregone earnings; basic education should be relevant to the jobs the trainees might seek. External providers of education must be made accountable - but with care; the system of accountability should also ensure that the needs of displaced workers most likely to suffer long-term unemployment are met. Not all displaced workers require relatively expansive retraining; some may need only inexpensive job-search assistance services. A permanent, institutionalized training system is preferable to short-term intervention.Labor Standards,Tertiary Education,ICT Policy and Strategies,Health Monitoring&Evaluation,Teaching and Learning
Assessment of the effect of honey and chlorhexidine on radiation-induced oral stomatitis with head-and-neck cancer patients
No full textBackground and Aim: Stomatitis being one of the most common oral complications of radiotherapy increases the mortality rates in patients with head and neck cancer. Providing preventive measures and cure for these side effects right after their onset is of primary importance. The aim of this study was to assess the effect of honey on radiation induced stomatitis in head and neck cancer patients. Materials and Methods: Thirty patients diagnosed with head-and-neck cancer requiring radiation or radiation combined with chemotherapy were divided into two groups. Patients of Group 1 were advised to mix 3 mL of chlorhexidine in 100 mL of water and rinse for about 1 min. Patients of Group 2 were advised to take 20 mL of honey in a glass of water and divide it into two equal parts and then rinse each part for about 30 s. Patients were evaluated at baseline, week 1, and week 2 for the development of radiation-induced stomatitis using the WHO Mucositis Scale. Results: The grade of stomatitis in head-and-neck cancer patients undergoing radiotherapy, treated with honey, was significantly lower than those treated with chlorhexidine (P < 0.05 for each). Conclusions: Topical application of honey is a simple and cost-effective treatment in radiation-induced stomatitis which needs further multicenter randomized trials to validate our finding. The results of the present study conducted on head-and-neck cancer patients will be useful in the administration of oral care. These findings are also important to the nurses who are assigned with the responsibility of stomatitis management
Third order nonlinear optical properties of graphene quantum dots under continuous wavelength regime at 532 nm
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