Investigation of refractory composites for liquid rocket engines Final report, 1 Oct. 1969 - 31 Oct. 1970

Oxidation resistance and high temperature tests of rhenium, tungsten, hafnium, and tantalum matrix composites with iridium in oxygen, fluorine, and boron atmospheres for liquid propellant engine

Current activities at IITRI on high- temperature protective coatings

Heat resistant protective coatings for use in liquid propellant rocket engine

A variational method from the variance of energy

A variational method is studied based on the minimum of energy variance. The method is tested on exactly soluble problems in quantum mechanics, and is shown to be a useful tool whenever the properties of states are more relevant than the eigenvalues. In quantum field theory the method provides a consistent second order extension of the gaussian effective potential.Comment: 5 ps figure

The Virtual Reconstruction of the Aesculapius and Hygeia Statues from the Sanctuary of Isis in Lilybaeum: Methods and Tools for Ancient Sculptures’ Enhancement

Thanks to recent technological developments in 3D surveys, computer graphics and virtual reality, new scenarios have been opened for the documentation and enhancement of ancient sculptures. When not totally preserved, sculptures can be digitally reproduced, modified and visualized to simulate their physical or virtual reconstruction in a non-invasive way for specialists or for dissemination aims. The virtual sculptural reconstruction process starts usually from the 3D survey of real fragments, and then continues by integrating missing parts with 3D modelling techniques by means of source evaluation. Along with primary data sources (reality-based model), secondary data sources (photos, drawings and 3D models of similar sculptures) can be directly used in the reconstruction process. This approach has a double advantage of making the reconstruction activities easier and less arbitrary, contributing to a decrease in the degree of uncertainty for the sculptural reconstruction work, also thanks to many iconographic comparisons to ancient copies. Moreover, virtual reconstruction can be easily visualized alongside a scalable rendering system using open-source Web3D apps and platforms, accessing information, 3D models and descriptions in order to enhance the experience of artworks. Inspecting theoretical and technical approaches, this work aims at establishing how primary and secondary data sources can be effectively used in sculptural reconstruction workflows, and how 3D outputs can be applied to implement digital sculptural heritage exploitation for museums and cultural institutions. The statues of Aesculapius and Hygeia from the sanctuary of Isis in Lilybaeum (Marsala, Italy) were chosen as a case study

The Winckelmann300 Project: Dissemination of Culture with Virtual Reality at the Capitoline Museum in Rome

The best way to disseminate culture is, nowadays, the creation of scenarios with virtual and augmented reality that supply the visitors of museums with a powerful, interactive tool that allows to learn sometimes difficult concepts in an easy, entertaining way. 3D models derived from reality-based techniques are nowadays used to preserve, document and restore historical artefacts. These digital contents are also powerful instrument to interactively communicate their significance to non-specialist, making easier to understand concepts sometimes complicated or not clear. Virtual and Augmented Reality are surely a valid tool to interact with 3D models and a fundamental help in making culture more accessible to the wide public. These technologies can help the museum curators to adapt the cultural proposal and the information about the artefacts based on the different type of visitor’s categories. These technologies allow visitors to travel through space and time and have a great educative function permitting to explain in an easy and attractive way information and concepts that could prove to be complicated. The aim of this paper is to create a virtual scenario and an augmented reality app to recreate specific spaces in the Capitoline Museum in Rome as they were during Winckelmann’s time, placing specific statues in their original position in the 18th century

Two-Loop Corrections to the Large-Order Behavior of Correlation Functions in the One-Dimensional N-Vector Model

For a long time, the predictive limits of perturbative quantum field theory have been limited by our inability to carry out loop calculations to an arbitrarily high order, which become increasingly complex as the order of perturbation theory is increased. This problem is exacerbated by the fact that perturbation series derived from loop diagram (Feynman diagram) calculations represent asymptotic (divergent) series which limits the predictive power of perturbative quantum field theory. Here, we discuss an ansatz that could overcome these limits, based on the observations that (i) for many phenomenologically relevant field theories, one can derive dispersion relations which relate the large-order growth (the asymptotic limit of infinite loop order ) with the imaginary part of arbitrary correlation functions, for negative coupling ( unstable vacuum ), and (ii) one can analyze the imaginary part for negative coupling in terms of classical field configurations (instantons). Unfortunately, the perturbation theory around instantons, which could lead to much more accurate predictions for the large-order behavior of Feynman diagrams, poses a number of technical as well as computational difficulties. Here, we study, to further the above-mentioned ansatz, correlation functions in a one-dimensional (1D) field theory with a quartic self-interaction and an O(N) internal symmetry group, otherwise known as the 1D N-vector model. Our focus is on corrections to the large-order growth of perturbative coefficients, i.e., the limit of a large number of loops in the Feynman diagram expansion. We evaluate, in momentum space, the two-loop corrections for the two-point correlation function, and its derivative with respect to the momentum, as well as the two-point correlation function with a wigglet insertion. Also, we study the four-point function. These quantities, computed at zero momentum transfer, enter the renormalization-group functions (Callan-Symanzik equation) of the model. Our calculations pave the way for further development of related methods in field theory and for a better understanding of field-theoretical expansions at large order

Received Cradling Bias During the First Year of Life: A Retrospective Study on Children With Typical and Atypical Development

A population-level left cradling bias exists whereby 60–90% of mothers hold their infants on the left side. This left biased positioning appears to be mutually beneficial to both the mother and the baby's brain organization for processing of socio-emotional stimuli. Previous research connected cradling asymmetries and Autism Spectrum Disorders (ASD), entailing impairment in socio-communicative relationships and characterized by an early hypo-lateralization of brain functions. In this explorative study, we aimed to provide a contribution to the retrospective investigations by looking for early behavioral markers of neurodevelopmental disorders such as ASD. We hypothesized that an atypical trajectory in maternal cradling might be one of the possible signs of an interference in mother-infant socio-emotional communication, and thus of potential neurodevelopmental dysfunctions. To this aim, we examined photos depicting mother-child early cradling interactions by consulting family albums of 27 children later diagnosed with ASD and 63 typically developing children. As regards the first half of the first year of life, no differences were shown between maternal cradling-side preferences in typical and ASD groups, both exhibiting the left-cradling bias in the 0–3 months period, but not in the 3–6 months period. However, our results show dissimilar patterns of cradling preferences during the second half of the first year of life. In particular, the absence of left-cradling shown in typical mothers was not observed in ASD mothers, who exhibited a significant left-cradling bias in the 6–12 months age group. This difference might reflect the fact that mother-infant relationship involving children later diagnosed with ASD might remain “basic” because mothers experience a lack of social activity in such children. Alternatively, it may reflect the overstimulation in which mothers try to engage infants in response to their lack of responsiveness and social initiative. However, further investigations are needed both to distinguish between these two possibilities and to define the role of early typical and reversed cradling experiences on neurodevelopment

Received cradling bias during the first year of life: A retrospective study on children with typical and atypical development

A population-level left cradling bias exists whereby 60-90% of mothers hold their infants on the left side. This left biased positioning appears to be mutually beneficial to both the mother and the baby’s brain organization for processing of socio-emotional stimuli. Previous research connected cradling asymmetries and Autism Spectrum Disorders (ASD), entailing impairment in socio- communicative relationships and characterized by an early hypo-lateralization of brain functions. In this explorative study, we aimed to provide a contribution to the retrospective investigations by looking for early behavioral markers of neurodevelopmental disorders such as ASD. We hypothesized that an atypical trajectory in maternal cradling might be one of the possible signs of an interference in mother-infant socio-emotional communication, and thus of potential neurodevelopmental dysfunctions. To this aim, we examined photos depicting mother-child early cradling interactions by consulting family albums of 27 children later diagnosed with autism and 63 typically developing children. As regards the first half of the first year of life, no differences were shown between maternal cradling-side preferences in typical and ASD groups, both exhibiting the left-cradling bias in the 0-3 months period, but not in the 3-6 months period. However, our results show dissimilar patterns of cradling preferences during the second half of the first year of life. In particular, the absence of left-cradling shown in typical mothers was not observed in ASD mothers, who exhibited a significant left-cradling bias in the 6-12 months age group. This difference might reflect the fact that mother-infant relationship involving children later diagnosed with ASD might remain “basic” because mothers experience a lack of social activity in such children. Alternatively, it may reflect the overstimulation in which mothers try to engage infants in response to their lack of responsiveness and social initiative. However, further investigations are needed both to distinguish between these two possibilities and to define the role of early typical and reversed cradling experiences on neurodevelopment

Looking at the Big Picture: Using Spatial Statistical Analyses to Study Indigenous Settlement Patterns in the North-Western Dominican Republic

After several field campaigns between 2007 and 2018 in the northwestern region of the Dominican Republic, more than 300 archaeological sites have been registered and revisited. While several of these sites were identified through the scatter of surface material culture, others show terrain modifications in the form of anthropogenic mounds and levelled areas. Researchers have gathered valuable information regarding these features’ functionality and construction processes through large-scale excavations in archaeological sites with anthropogenic mounds, paleoenvironmental studies and remote sensing analyses. These anthropogenic mounds represent a long-term process of formation and were used for a variety of purposes ranging from agricultural to ritual activities. While excavations and small-scale remote sensing can provide a myriad of data to improve our understanding of these archaeological sites, a regional perspective is needed to map the relationship among archaeological sites with and without terrain modifications, to better understand the Indigenous cultural patterns in their regional environment. In this regard, the primary objective of this paper is to explore to what extent these archaeological sites were related to the environment and each other. This was achieved by correlating archaeological data with a set of archaeologically recognized important environmental variables using advanced spatial statistics. The results provide important insights to understand the underlying pattern of archaeological sites in this region and its relationship with the environmental setting