1,139 research outputs found
Tensile and Compressive Constitutive Response of 316 Stainless Steel at Elevated Temperatures
Creep rate in compression is lower by factors of 2 to 10 than in tension if the microstructure of the two specimens is the same and are tested at equal temperatures and equal but opposite stresses. Such behavior is characteristic for monotonic creep and conditions involving cyclic creep. In the latter case creep rate in both tension and compression progressively increases from cycle to cycle, rendering questionable the possibility of expressing a time stabilized constitutive relationship. The difference in creep rates in tension and compression is considerably reduced if the tension specimen is first subjected to cycles of tensile creep (reversed by compressive plasticity), while the compression specimen is first subjected to cycles of compressive creep (reversed by tensile plasticity). In both cases, the test temperature is the same and the stresses are equal and opposite. Such reduction is a reflection of differences in microstructure of the specimens resulting from different prior mechanical history
Performance analysis of an interacting quantum dot thermoelectric system
We analyze the nanocaloritronic performance of an interacting quantum dot
that is subject to an applied bias and an applied temperature gradient. It is
now well known that, in the absence of phonon contribution, a weakly coupled
non-interacting quantum dot can operate at thermoelectric efficiencies
approaching the Carnot limit. However, it has also been recently pointed out
that such peak efficiencies can only be achieved when operated in the
reversible limit, with a vanishing current and hence a vanishing power output.
In this paper, we point out three fundamental results affecting the
thermoelectric performance due to the inclusion of Coulomb interactions: a) The
reversible operating point carries zero efficiency, b) operation at finite
power output is possible even at peak efficiencies approaching the Carnot
value, and c) the evaluated trends of the the maximum efficiency deviate
considerably from the conventional {\it{figure of merit}} based result.
Finally, we also analyze our system for thermoelectric operation at maximum
power output.Comment: 10 pages, 6 figures, Resubmission- to be published in Phys. Rev.
Influence of fat content on the quality and shelf life of cured sardines
The paper presents results of studies on the effect of seasonal variations in the fat content on the quality and shelf life of dry cured, pickle cured and smoke cured oil sardines. The merits and defects of each method of curing during different seasons are discussed
Evaluation of Post Extraction Hemostasis in Cardiac Patients with Gelatamp Dental Dressing Without Stopping Aspirin and Clopidogrel Therapy
AIM :
The aim of the study is to evaluate clinically the use of Gelatamp dental dressing as a hemostatic agent in cardiac patients continuing aspirin and clopidogrel following dental extraction.
MATERIALS AND METHODS :
A randomized prospective controlled clinical trial was carried out among the cardiac patients attending the Department of Oral and Maxillofacial Surgery, Best Dental Science College, Madurai district to evaluate the post extraction hemostasis without stopping aspirin and/ or clopidogrel therapy. This study was conducted on 88 patients indicated for teeth extraction divided into two equal groups. Study group consisting of 44 patients who received their medicine as usual and extraction was done followed by insertion of gelatamp in the socket and sutured with 3.0 black silk. Control group consisting of 44 patients who also received their medicine and socket is sutured with 3.0 black silk without placing any haemostatic agent into the socket. The post-operative bleeding had been monitored immediately, 5 minutes, 30 minutes, 2 hours, 24 hours and 7th day after extraction in both groups.
RESULTS :
The incidence of postoperative bleeding was higher in the control group (grade 2, 36/44, 81.8 %) than in the study group (grade 2 15/44, 34.1 %) immediately after extraction. The post-operative bleeding after 5 minutes is also found to be higher in control group (grade 1- 31/44, 70.4 %) compared to study group ( grade 1 – 12/44,
27.2%) but the difference was statistically not significant. In 30 minutes after extraction the bleeding was very less in study group (grade 1- 1/44, 2.3 %) when compared to control group. No life-threatening complications were reported and no transfusions were required.
CONCLUSION :
Gelatamp is an effective alternative local hemostatic agent after extraction in cardiac patients (within the therapeutic range of INR) without interruption of the apirin and clopidogrel therapy
The mealybug chromosome system I: unusual methylated bases and dinucleotides in DNA of a Planococcus species
The methylation status of the nuclear DNA from a mealybug, a Planococcus species, has been studied. Analysis of this DNA by High Performance Liquid Chromatography and Thin Layer Chromatography revealed the presence of significant amounts of 5--methylcytosine. Since analysis of DNA methylation using the Msp I/Hpa II system showed only minor differences in susceptibility of the DNA to the two enzymes, it seemed possible that 5-methylcytosine (5mC) occurred adjacent to other nucleotides in addition to its usual position, next to guanosine. This was verified by dinucleotide analysis of DNA labelledin vitro by nick translation. These data show that the total amount of 5-methylcytosine in this DNA is slightly over 2.3 mol %, of which 0.61% occurs as the dinucleotide 5mCpG, 0.68% as 5mCpA, 0.59% as 5mCpT and 0.45% as 5mCpC. 5mCpG represents approximately 3.3% of all CpG dinucleotides. The experimental procedure would not have permitted the detection of 5mCp5mC, if it occurs in this system. Unusually high amounts of 6-methyladenine (approximately 4 mol %) and 7-methylguanine (approximately 2 mol %) were also detected, 6-methyladenine and 7-methylguanine occurred adjacent to all four nucleotides. The total G+C content was 33.7% as calculated from dinucleotide data and 32.9% as determined from melting profiles
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Development of Stronger and More Reliable Cast Austenitic Stainless Steels (H-Series) Based on Scientific Design Methodology
The goal of this program was to increase the high-temperature strength of the H-Series of cast austenitic stainless steels by 50% and upper use temperature by 86 to 140 F (30 to 60 C). Meeting this goal is expected to result in energy savings of 38 trillion Btu/year by 2020 and energy cost savings of 185 million/year. The goal of the project was achieved by using the alloy design methods developed at ORNL, based on precise microcharacterization and identification of critical microstructure/properties relationships and combining them with the modern computational science-based tools that calculate phases, phase fractions, and phase compositions based on alloy compositions. The combined approach of microcharacterization of phases and computational phase prediction would permit rapid improvement of the current alloy composition of an alloy and provide the long-term benefit of customizing alloys within grades for specific applications. The project was appropriate for the domestic industry because the current H-Series alloys have reached their limits both in high-temperature-strength properties and in upper use temperature. The desire of Duraloy's industrial customers to improve process efficiency, while reducing cost, requires that the current alloys be taken to the next level of strength and that the upper use temperature limit be increased. This project addressed a specific topic from the subject call: to develop materials for manufacturing processes that will increase high-temperature strength, fatigue resistance, corrosion, and wear resistance. The outcome of the project would benefit manufacturing processes in the chemical, steel, and heat-treating industries
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