scholarly journals O uso de madeira como combustível no sítio da Quinta de Crestelos (Baixo Sabor): da Idade do Ferro à Romanização

2020 ◽  
pp. 1191-1206
Author(s):  
Filipe Vaz ◽  
João Tereso ◽  
Sérgio Simões Pereira ◽  
José Sastre ◽  
Javier Larrazabal Galarza ◽  
...  
Keyword(s):  
Large Set ◽  
Charcoal Analysis ◽  
Functional Area ◽  
Two Sectors

A large set of archaeobotanical samples were recovered during the excavation of Quinta de Crestelos (Mogadouro), several of which have already been published. This paper focusses on the charcoal analysis still unpublished from two sectors of this site. The first, located in the lower platform, relates to a habitation area comprised of huts and fireplaces from the 4th to the 2nd centuries BC. The second is a functional area with three ovens of different typologies dating to the 1st – 2nd centuries AD. Results revealed a diverse set of taxa, dominated by evergreen and deciduous oak, heath, pine and ash. This data allowed to access uses of wood in the site, namely their relation to the function and type of structures where they have been found.

Ab initio band theory approach to electron energy loss near edge structures

1988 ◽  
Vol 46 ◽  
pp. 506-507
Author(s):  
Xudong Weng ◽  
O.F. Sankey ◽  
Peter Rez
Keyword(s):  
Ab Initio ◽  
Local Density ◽  
Interpolation Method ◽  
Atomic Orbital ◽  
Plane Waves ◽  
Large Set ◽  
Theory Approach ◽  
Band Theory ◽  
Atomic Orbitals ◽  
Pseudopotential Calculations

Single electron band structure techniques have been applied successfully to the interpretation of the near edge structures of metals and other materials. Among various band theories, the linear combination of atomic orbital (LCAO) method is especially simple and interpretable. The commonly used empirical LCAO method is mainly an interpolation method, where the energies and wave functions of atomic orbitals are adjusted in order to fit experimental or more accurately determined electron states. To achieve better accuracy, the size of calculation has to be expanded, for example, to include excited states and more-distant-neighboring atoms. This tends to sacrifice the simplicity and interpretability of the method.In this paper. we adopt an ab initio scheme which incorporates the conceptual advantage of the LCAO method with the accuracy of ab initio pseudopotential calculations. The so called pscudo-atomic-orbitals (PAO's), computed from a free atom within the local-density approximation and the pseudopotential approximation, are used as the basis of expansion, replacing the usually very large set of plane waves in the conventional pseudopotential method. These PAO's however, do not consist of a rigorously complete set of orthonormal states.

Molecular Views of Ice-Embedded Lumbricus Terrestris Erythrocruorin Obtained By Invariant Classification

1990 ◽  
Vol 48 (1) ◽  
pp. 450-451
Author(s):  
Michael schatz ◽  
Joachim Jäger ◽  
Marin van Heel
Keyword(s):  
Image Interpretation ◽  
Lumbricus Terrestris ◽  
Reference Image ◽  
Large Set ◽  
Multivariate Statistical ◽  
Data Set ◽  
Low Contrast ◽  
Negative Stain ◽  
Reference Images ◽  
Statistical Resolution

Lumbricus terrestris erythrocruorin is a giant oxygen-transporting macromolecule in the blood of the common earth worm (worm "hemoglobin"). In our current study, we use specimens (kindly provided by Drs W.E. Royer and W.A. Hendrickson) embedded in vitreous ice (1) to avoid artefacts encountered with the negative stain preparation technigue used in previous studies (2-4).Although the molecular structure is well preserved in vitreous ice, the low contrast and high noise level in the micrographs represent a serious problem in image interpretation. Moreover, the molecules can exhibit many different orientations relative to the object plane of the microscope in this type of preparation. Existing techniques of analysis requiring alignment of the molecular views relative to one or more reference images often thus yield unsatisfactory results.We use a new method in which first rotation-, translation- and mirror invariant functions (5) are derived from the large set of input images, which functions are subsequently classified automatically using multivariate statistical techniques (6). The different molecular views in the data set can therewith be found unbiasedly (5). Within each class, all images are aligned relative to that member of the class which contributes least to the classes′ internal variance (6). This reference image is thus the most typical member of the class. Finally the aligned images from each class are averaged resulting in molecular views with enhanced statistical resolution.

A Double Interaction Brush Model for Snow Conditions

2019 ◽  
Vol 47 (2) ◽  
pp. 118-140
Author(s):  
Artem Kusachov ◽  
Fredrik Bruzelius ◽  
Mattias Hjort ◽  
Bengt J. H. Jacobson
Keyword(s):  
Low Complexity ◽  
Large Set ◽  
Tire Model ◽  
Vehicle Handling ◽  
Real Time Applications ◽  
Snow Conditions ◽  
Double Interaction ◽  
Tire Models ◽  
Force Characteristics ◽  
Model Approach

ABSTRACT Commonly used tire models for vehicle-handling simulations are derived from the assumption of a flat and solid surface. Snow surfaces are nonsolid and may move under the tire. This results in inaccurate tire models and simulation results that are too far from the true phenomena. This article describes a physically motivated tire model that takes the effect of snow shearing into account. The brush tire model approach is used to describe an additional interaction between the packed snow in tire tread pattern voids with the snow road surface. Fewer parameters and low complexity make it suitable for real-time applications. The presented model is compared with test track tire measurements from a large set of different tires. Results suggest higher accuracy compared with conventional tire models. Moreover, the model is also proven to be capable of correctly predicting the self-aligning torque given the force characteristics.

Adsorption Isotherm Predictions for Multiple Molecules in MOFs Using the Same Deep Learning Model

2019 ◽  
Author(s):  
Ryther Anderson ◽  
Achay Biong ◽  
Diego Gómez-Gualdrón
Keyword(s):  
Neural Network ◽  
Machine Learning ◽  
Molecular Simulation ◽  
Large Scale ◽  
Learning Model ◽  
Operating Conditions ◽  
Small Subset ◽  
Screening Methods ◽  
Large Set ◽  
Metal Organic

<div>Tailoring the structure and chemistry of metal-organic frameworks (MOFs) enables the manipulation of their adsorption properties to suit specific energy and environmental applications. As there are millions of possible MOFs (with tens of thousands already synthesized), molecular simulation, such as grand canonical Monte Carlo (GCMC), has frequently been used to rapidly evaluate the adsorption performance of a large set of MOFs. This allows subsequent experiments to focus only on a small subset of the most promising MOFs. In many instances, however, even molecular simulation becomes prohibitively time consuming, underscoring the need for alternative screening methods, such as machine learning, to precede molecular simulation efforts. In this study, as a proof of concept, we trained a neural network as the first example of a machine learning model capable of predicting full adsorption isotherms of different molecules not included in the training of the model. To achieve this, we trained our neural network only on alchemical species, represented only by their geometry and force field parameters, and used this neural network to predict the loadings of real adsorbates. We focused on predicting room temperature adsorption of small (one- and two-atom) molecules relevant to chemical separations. Namely, argon, krypton, xenon, methane, ethane, and nitrogen. However, we also observed surprisingly promising predictions for more complex molecules, whose properties are outside the range spanned by the alchemical adsorbates. Prediction accuracies suitable for large-scale screening were achieved using simple MOF (e.g. geometric properties and chemical moieties), and adsorbate (e.g. forcefield parameters and geometry) descriptors. Our results illustrate a new philosophy of training that opens the path towards development of machine learning models that can predict the adsorption loading of any new adsorbate at any new operating conditions in any new MOF.</div>

On Capital Allocation And The Real Cost Of Labour (Notes & Comments)

1970 ◽  
Vol 10 (4) ◽  
pp. 491-499
Author(s):  
F. E. Banks
Keyword(s):  
Agricultural Sector ◽  
Wage Differential ◽  
Industrial Sector ◽  
Capital Allocation ◽  
Marginal Product ◽  
Developing Economy ◽  
Real Cost ◽  
The Difference ◽  
Industrial Wage ◽  
Two Sectors

This note is an extension of several contributions to the problem of re¬source allocation in a developing economy. In separate papers, I.M.D. Little and F. Seton* have introduced a model in which labour in a developing economy cannot be shifted from the subsistence to the industrial sector at zero opportunity cost, even though this labour displays zero marginal product in its 'traditional' occupations; and in what follows this problem will be attacked via a diagramma¬tic analysis. A short appendix will treat a side issue of the topic. As Little presented the model, there was an initial amount of capital K to be divided between two sectors, the I (industrial) sector, and the C (subsistence, traditional, or agricultural) sector. In the C-sector, there is excess labour or dis¬guised unemployment, in the sense of Professor W. A. Lewis2, in that the marginal product of labour in this sector is taken as equal to zero. As it happens, however, this labour cannot be moved to the I-Sector without an increase in production in the C-sector. The reason for this is because as labour is transferred to the industrial sector, consumption per head increases in the C-sector, thus decreasing the surplus available for workers being transferred to the I-sector. The transfer can only be carried out if a surplus equal to the difference between the industrial wage in C-goods and the amount of C-goods 'released' by the C-sector is forth¬coming, and for this an increased production of C-goods (via the input of capital into the C-sector) must take place. A similar situation would exist if transferring workers required a wage differential; or if C-goods had to be exported to obtain certain types of capital goods for the labour being reallocated, and/or housing, training, etc.

Trees and shrubs in the sanctuary. Wood charcoal analysis at the Sanctuary of Poseidon at Kalaureia, Poros

2019 ◽  
pp. 255-269 ◽  
Author(s):  
Maria Ntinou
Keyword(s):  
Iron Age ◽  
Economic Activity ◽  
Wood Charcoal ◽  
Early Iron Age ◽  
Hellenistic Period ◽  
Charcoal Analysis ◽  
Additional Source ◽  
Olive Cultivation ◽  
Trees And Shrubs ◽  
By Products

Wood charcoal analysis at the Sanctuary of Poseidon at Kalaureia, Poros aims to provide information on the vegetation of the area and its management and on the range of plants used in the activities taking place at the sanctuary. During the excavations of 2003–2005 in Areas D and C, systematic samples from fills and features from all the excavated strata were recovered and water flotation was used for the separation of wood charcoal from the sediment. Wood charcoal was found in two pits dated to the Early Iron Age, near the supposed altar of the Archaic period (Feature 05), in a deposit of the Hellenistic period (the “dining deposit”), in floor deposits (Early Iron Age and Late Classical/Early Hellenistic periods), and fills of different chrono-cultural periods (Archaic–Early Roman). All the taxa identified in the wood charcoal assemblages are thermophilous Mediterranean elements, most of them evergreen broad-leaved. The assemblages show that the most frequent taxon is the olive, followed by the prickly oak, the Fabaceae, and the heather. In most assemblages mock privet/buckthorn, strawberry tree, the pear and Prunus family species are present, while Aleppo pine, lentisc, the fig, and the carob trees are less frequent. Olive cultivation was an important economic activity during the whole life of the sanctuary and probably olive pruning constantly provided the sanctuary with fuel. The woodland would be the additional source of firewood for the sanctuary’s needs for fuel for mundane activities such as heating and cooking, for more formal ones, such as sacrifice, but also for industrial activities such as tile firing. Activities related to the reorganization of space and the expansion of the sanctuary may be reflected in charcoal of carpentry by-products as the fir, cypress, and maybe pine remains.

Domina Paupertas: the praise of voluntary poverty by St. Francis of Assisi and its reflection in late medieval Spanish painting

2014 ◽  
Vol 14 (2) ◽  
pp. 105
Author(s):  
José María Salvador González
Keyword(s):  
San Francisco ◽  
Middle Ages ◽  
Jesus Christ ◽  
Large Set ◽  
Late Medieval ◽  
Late Middle Ages ◽  
Perfect Model ◽  
Material Goods ◽  
Potential Impact ◽  
Francis Of Assisi

As is well known, St. Francis of Assisi heroically embraced evangelical poverty, renouncing material goods and living in abject poverty, in imitation of Jesus Christ. Furthermore, through his writings and oral testimonies collected by his disciples, the saint fervently urged Christians to live to some degree voluntary poverty , of which Christ was the perfect model. By basing this reading on some Poverello’s quotations, this paper intends to show the potential impact that these exhortations from San Francisco to poverty may have had in the late medieval Spanish painting, in some iconographic themes so significantly Franciscan as the Nativity and the Passion of the Redeemer. Through the analysis of a large set of paintings representing both issues, we will attempt to put into light if the teachings of St. Francis on evangelical poverty are reflected somehow in Spanish painting of the late Middle Ages.

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