Search results for "Cold"
showing 10 items of 660 documents
Mass-asymmetric fission in the 40ca+142Nd reaction
2016
Shell effects play a major role in fission. Mass-asymmetric fission observed in the spontaneous and low energy fission of actinide nuclei was explained by incorporating the fragment shell properties in liquid drop model. Asymmetric fission has also been observed in the low energy fission of neutron-deficient 180 Hg nuclei in recent β -delayed fission experiments. This low-energy β -delayed fission has been explained in terms of strong shell effects in pre-scission configurations associated with the system after capture. Calculations predicted asymmetric fission for heavier Hg isotopes as well, at compound nuclear excitation energy as high as 40 MeV. To explore the evolution of fission fragm…
Decreased temperature increases the expression of a disordered bacterial late embryogenesis abundant (LEA) protein that enhances natural transformati…
2021
Late embryogenesis abundant (LEA) proteins are important players in the management of responses to stressful conditions, such as drought, high salinity, and changes in temperature. Many LEA proteins do not have defined three-dimensional structures, so they are intrinsically disordered proteins (IDPs) and are often highly hydrophilic. Although LEA-like sequences have been identified in bacterial genomes, the functions of bacterial LEA proteins have been studied only recently. Sequence analysis of outer membrane interleukin receptor I (BilRI) from the oral pathogen Aggregatibacter actinomycetemcomitans indicated that it shared sequence similarity with group 3/3b/4 LEA proteins. Comprehensive …
Effect of Nitrogen Fertilization on the Quality of Swiss Chard at Harvest and during Storage as Minimally Processed Produce
2014
The effects of different levels of nitrogen fertilization (0–50–100–150–200 kg/ha), minimal processing and cold storage (14 days at 4C) on yield and quality of fresh-cut Swiss chard (Beta vulgaris L. var. cicla L.) were evaluated. Increasing the level of nitrogen fertilization over 100 kg N/ha, plants had a higher fresh weight, reduced their dry matter content and resulted taller and leafier. Total and marketable yield increased linearly with increasing nitrogen level. Both nitrate and ascorbic acid content at harvest increased with increasing nitrogen supply. Nitrogen fertilization negatively affected the yield of minimal processing. No effect on appearance and quality loss during cold sto…
Effect of the indentation process on fatigue life of drilled specimens
2015
Design and manufacture of mechanical elements are strongly influenced by the evaluation of the residual stresses due to their effects on the material strength. This paper presents numerical and experimental results performed on AW 6082-T6 aluminum alloy drilled specimens when the hole is created after a bilateral indentation process. The plastic deformation induced by the indenters creates a compressive residual stress field around the hole, which persists after the drilling operation. Several numerical analysis have been carried out in ANSYS APDL explicit solver for different indentation depths and hole diameters in order to evaluate the compressive circumferential stresses, optimal proces…
Identifying conserved genes involved in crop tolerance to cold stress
2022
Low temperature is a limiting factor for crop productivity in tropical and subtropical climates. Cold stress response in plants involves perceiving and relaying the signal through a transcriptional cascade composed of different transduction components, resulting in altered gene activity. We performed a meta-analysis of four previously published datasets of cold-tolerant and cold-sensitive crops to better understand the gene regulatory networks and identify key genes involved in cold stress tolerance conserved across phylogenetically distant species. Re-analysing the raw data with the same bioinformatics pipeline, we identified common cold tolerance-related genes. We found 236 and 242 common…
Recent Developments in the Design and Control of Cold Forming Processes
1999
In the paper some problems of process design and control in metal forming are taken into account. In particular as far as the former aspect is concerned, the problem of the preform design in cold forging is analyzed: the contributions offered by several researchers are presented and an innovative design procedure is proposed. As well, the suitability of closed-loop control systems for metal forming applications is discussed with particular reference to sheet stamping operations; again, after an overview of the state of the art, the advantages offered by the application in this field of Artificial Intelligence techiniques is pointed out.
Direct observation of second-order atom tunnelling
2007
Tunnelling of material particles through a classically impenetrable barrier constitutes one of the hallmark effects of quantum physics. When interactions between the particles compete with their mobility through a tunnel junction, intriguing novel dynamical behaviour can arise where particles do not tunnel independently. In single-electron or Bloch transistors, for example, the tunnelling of an electron or Cooper pair can be enabled or suppressed by the presence of a second charge carrier due to Coulomb blockade. Here we report on the first direct and time-resolved observation of correlated tunnelling of two interacting atoms through a barrier in a double well potential. We show that for we…
A Scanning Electron Microscope for Ultracold Atoms
2006
We propose a new technique for the detection of single atoms in ultracold quantum gases. The technique is based on scanning electron microscopy and employs the electron impact ionization of trapped atoms with a focussed electron probe. Subsequent detection of the resulting ions allows for the reconstruction of the atoms position. This technique is expected to achieve a much better spatial resolution compared to any optical detection method. In combination with the sensitivity to single atoms, it makes new in situ measurements of atomic correlations possible. The detection principle is also well suited for the addressing of individual sites in optical lattices.
Time-resolved Observation and Control of Superexchange Interactions with Ultracold Atoms in Optical Lattices
2007
Quantum mechanical superexchange interactions form the basis of quantum magnetism in strongly correlated electronic media. We report on the direct measurement of superexchange interactions with ultracold atoms in optical lattices. After preparing a spin-mixture of ultracold atoms in an antiferromagnetically ordered state, we measure a coherent superexchange-mediated spin dynamics with coupling energies from 5 Hz up to 1 kHz. By dynamically modifying the potential bias between neighboring lattice sites, the magnitude and sign of the superexchange interaction can be controlled, thus allowing the system to be switched between antiferromagnetic or ferromagnetic spin interactions. We compare our…
A low-pass velocity filter for ultracold neutrons
2012
Abstract We have built a device to filter ultracold neutrons with axial velocities v n ≤ 8.0 m / s from faster neutrons. The apparatus has been successfully tested at the Institut Laue-Langevin in Grenoble and is used in specific experiments, e.g., the measurement of ultracold neutron transmission through various types of neutron guides.