2,981 research outputs found
Suitable classification of mortars from ancient roman and renaissance frescoes using thermal analysis and chemometrics
Background
Literature on mortars has mainly focused on the identification and characterization of their components in order to assign them to a specific historical period, after accurate classification. For this purpose, different analytical techniques have been proposed. Aim of the present study was to verify whether the combination of thermal analysis and chemometric methods could be used to obtain a fast but correct classification of ancient mortar samples of different ages (Roman era and Renaissance).
Results
Ancient Roman frescoes from Museo Nazionale Romano (Terme di Diocleziano, Rome, Italy) and Renaissance frescoes from Sistine Chapel and Old Vatican Rooms (Vatican City) were analyzed by thermogravimetry (TG) and differential thermal analysis (DTA). Principal Component analysis (PCA) on the main thermal data evidenced the presence of two clusters, ascribable to the two different ages. Inspection of the loadings allowed to interpret the observed differences in terms of the experimental variables.
Conclusions
PCA allowed differentiating the two kinds of mortars (Roman and Renaissance frescoes), and evidenced how the ancient Roman samples are richer in binder (calcium carbonate) and contain less filler (aggregate) than the Renaissance ones. It was also demonstrated how the coupling of thermoanalytical techniques and chemometric processing proves to be particularly advantageous when a rapid and correct differentiation and classification of cultural heritage samples of various kinds or ages has to be carried out
Preliminary findings from a survey on the MD state of the practice
In the context of an Italian research project, this paper reports on an on-line survey, performed with 155 software professionals, with the aim of investigating about their opinions and experiences in modeling during software development and Model-driven engineering usage. The survey focused also on used modeling languages, processes and tools. A preliminary analysis of the results confirmed that Model-driven engineering, and more in general software modeling, are very relevant phenomena. Approximately 68% of the sample use models during software development. Among then, 44% generate code starting from models and 16% execute them directly. The preferred language for modeling is UML but DSLs are used as wel
Tool-automation for supporting the DSL learning process
Recent technologies advances reduced significantly the effort needed to develop Domain Specific Languages (DSLs), enabling the transition to language oriented software development. In this scenario new DSLs are developed and evolve at fast-pace, to be used by a small user-base. This impose a large effort on users to learn the DSLs, while DSL designers can use little feedback to guide successive evolutions, usually just based on anecdotal considerations.
We advocate that a central challenge with the proliferation of DSLs is to help users to learn the DSL and providing useful analyses to the language designers, to understand what is working and what is not in the developed DSL.
In this position paper we sketch possible directions for tool-automation to support the learning processes associated with DSL adoption and to permit faster evolution cycles of the DSLs
Simplified methodologies for assessing the out-of-plane two-way bending seismic response of unreinforced brick masonry walls: lessons from recent experimental studies
This paper describes a simplified methodology for the assessment of unreinforced masonry (URM) walls under out-of-plane two-way bending seismic action. The methodology involves a force-based check derived from the principle of virtual work. This check is proposed based on experimental observations of significant cracking resistance associated with two-way spanning URM walls, indicating methodologies considering such walls to be pre-cracked or to be non-laterally supported as overly conservative. The methodology incorporates several findings and developments from recent experimental campaigns: ranging from novel characterization tests on masonry couplets to incremental dynamic tests on full-scale buildings. Such incorporations include new formulation to calculate the torsional shear strength of a bed joint and accounting for possible changes in the boundary conditions of an OOP wall during dynamic loading. Testing standards as well as recommendations in several international guidelines for masonry structures addressing the input properties required to implement the proposed methodology are enlisted and reviewed. The methodology requires the definition of the period of vibration of the assessed URM walls, to calculate which plate theory based formulation is provided. Open research questions and potential avenues for further development of the methodology are ultimately highlighted
EFFECT OF AN INNOVATIVE ISOLATION SYSTEM ON THE SEISMIC RESPONSE OF CULTURAL HERITAGE BUILDING CONTENTS
An experimental study was conducted at the University of Pavia and at the EUCENTRE Foundation (Pavia, Italy) to assess the effectiveness of an innovative seismic isolation device at protecting cultural heritage building contents. The recently patented isolator, named “Kinematic Steel Joint (KSJ)”, is based on a multiple articulated quadrilateral mechanism and is entirely made of steel components obtained by simply cutting, folding, and pinning metal sheets, eventually employing stainless steel to limit corrosion issues. The trajectory imposed by the KSJ isolator to the supported mass combines horizontal with increasing vertical displacements, resulting in a pendulum-type motion with self-centering behavior. The friction developing within the pinned joints can be exploited to grant energy dissipation capacity to the device. The KSJ isolator can be manufactured with different sizes, payloads, and displacement ranges. In fact, seismic isolation can be applied at a global building level as an integrated system or as a retrofit solution in new or existing construction, respectively, or at a local scale as a passive protection technique for non-structural components. Despite their undeniable effectiveness in reducing the seismic accelerations transmitted to the isolated structure and to its content, currently available isolation devices may add significantly to the construction cost of buildings, and may require particular maintenance to preserve a stable performance over time. The proposed KSJ solution will allow for a reduction in manufacturing and maintenance burdens compared to established technologies.
This paper discusses the main results of a shake-table test conducted at the EUCENTRE Foundation laboratories on an assembly with four prototypes of the KSJ device. The experimental setup included a 19-t rigid mass supported by the isolators, simulating the building superstructure, and four marble blocks installed above the rigid mass, representing non-structural rocking components such as parapets, pinnacles, statues, or other architectural ornaments. Moreover, a museum showcase with a small-scale replica of Michelangelo’s David was mounted above the rigid block, while two clay vases completed the setup, to encompass additional cultural heritage features. Accelerometers and potentiometers were deployed at several locations to monitor the kinematic response of the individual isolators, as well as their effect on the dynamic response of the rigid mass and of the different non-structural elements. The experiment was conducted first with the KSJ devices allowed to displace freely, then after fastening the rigid mass to the shake-table through post-tensioning rods, following the same incremental dynamic test sequence. This allowed comparing the response of the non-structural components with and without seismic isolation, to better understand the effect of the proposed isolation devices on the overall test assembly and on each sub-component
Insights into CSF-1R Expression in the Tumor Microenvironment
The colony-stimulating factor 1 receptor (CSF-1R) plays a pivotal role in orchestrating cellular interactions within the tumor microenvironment (TME). Although the CSF-1R has been extensively studied in myeloid cells, the expression of this receptor and its emerging role in other cell types in the TME need to be further analyzed. This review explores the multifaceted functions of the CSF-1R across various TME cellular populations, including tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), dendritic cells (DCs), cancer-associated fibroblasts (CAFs), endothelial cells (ECs), and cancer stem cells (CSCs). The activation of the CSF-1R by its ligands, colony-stimulating factor 1 (CSF-1) and Interleukin-34 (IL-34), regulates TAM polarization towards an immunosuppressive M2 phenotype, promoting tumor progression and immune evasion. Similarly, CSF-1R signaling influences MDSCs to exert immunosuppressive functions, hindering anti-tumor immunity. In DCs, the CSF-1R alters antigen-presenting capabilities, compromising immune surveillance against cancer cells. CSF-1R expression in CAFs and ECs regulates immune modulation, angiogenesis, and immune cell trafficking within the TME, fostering a pro-tumorigenic milieu. Notably, the CSF-1R in CSCs contributes to tumor aggressiveness and therapeutic resistance through interactions with TAMs and the modulation of stemness features. Understanding the diverse roles of the CSF-1R in the TME underscores its potential as a therapeutic target for cancer treatment, aiming at disrupting pro-tumorigenic cellular crosstalk and enhancing anti-tumor immune responses
Secondary Cosmic Ray Nuclei from Supernova Remnants and Constraints to the Propagation Parameters
The secondary-to-primary B/C ratio is widely used to study the cosmic ray
(CR) propagation processes in the Galaxy. It is usually assumed that secondary
nuclei such as Li-Be-B are entirely generated by collisions of heavier CR
nuclei with the interstellar medium (ISM). We study the CR propagation under a
scenario where secondary nuclei can also be produced or accelerated from
galactic sources. We consider the processes of hadronic interactions inside
supernova remnants (SNRs) and re-acceleration of background CRs in strong
shocks. Thus, we investigate their impact in the propagation parameter
determination within present and future data. The spectra of Li-Be-B nuclei
emitted from SNRs are harder than those due to CR collisions with the ISM. The
secondary-to-primary ratios flatten significantly at ~TeV/n energies, both from
spallation and re-acceleration in the sources. The two mechanisms are
complementary to each other and depend on the properties of the local ISM
around the expanding remnants. The secondary production in SNRs is significant
for dense background media, n ~1 cm^-3, while the amount of re-accelerated CRs
is relevant for SNRs expanding into rarefied media, n ~0.1 cm-3. Due to these
effects, the the diffusion parameter 'delta' may be misunderstood by a factor
of ~5-15%. Our estimations indicate that an experiment of the AMS-02 caliber
can constrain the key propagation parameters while breaking the
source-transport degeneracy, for a wide class of B/C-consistent models. Given
the precision of the data expected from on-going experiments, the SNR
production/acceleration of secondary nuclei should be considered, if any, to
prevent a possible mis-determination of the CR transport parameters.Comment: 13 pages, 9 figures; matches the published versio
Penetrating particle ANalyzer (PAN)
PAN is a scientific instrument suitable for deep space and interplanetary
missions. It can precisely measure and monitor the flux, composition, and
direction of highly penetrating particles (100 MeV/nucleon) in deep
space, over at least one full solar cycle (~11 years). The science program of
PAN is multi- and cross-disciplinary, covering cosmic ray physics, solar
physics, space weather and space travel. PAN will fill an observation gap of
galactic cosmic rays in the GeV region, and provide precise information of the
spectrum, composition and emission time of energetic particle originated from
the Sun. The precise measurement and monitoring of the energetic particles is
also a unique contribution to space weather studies. PAN will map the flux and
composition of penetrating particles, which cannot be shielded effectively,
precisely and continuously, providing valuable input for the assessment of the
related health risk, and for the development of an adequate mitigation
strategy. PAN has the potential to become a standard on-board instrument for
deep space human travel.
PAN is based on the proven detection principle of a magnetic spectrometer,
but with novel layout and detection concept. It will adopt advanced particle
detection technologies and industrial processes optimized for deep space
application. The device will require limited mass (~20 kg) and power (~20 W)
budget. Dipole magnet sectors built from high field permanent magnet Halbach
arrays, instrumented in a modular fashion with high resolution silicon strip
detectors, allow to reach an energy resolution better than 10\% for nuclei from
H to Fe at 1 GeV/n
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