Chapter 8: A Template for Structured Problems

Laminate zeolite structure prepared using papermaking techniques for carbon dioxide capture: synthesis, characterisation and performance

Atom lithography is a technique to structure layers of atoms during deposition, using interactions of near-resonant light fields with neutral atoms. The basic scheme uses a standing wave light field, aligned just above a substrate, while a beam of atoms impinges perpendicularly on the standing wave light field. The interaction of the light field and the atoms focuses the atoms towards the crests or troughs of the standing wave intensity, dependent on the tuning of the light field. The focused atoms are subsequently deposited on the substrate, resulting in an array of lines, whose periodicity is determined by the wavelength of the light field. The standing wave light field can therefore be seen as an array of lenses, focusing the atom beam into an array of lines. The first experiments on atom lithography were performed in the 1990s with sodium and chromium. In this thesis experiments with iron are described, which is a magnetic element and thus allows for the creation of magnetic nanostructures. To focus atom beams into structures using atom lithography, well-colimated atom beams are required. The most common technique to create collimated atom beams is transverse laser cooling, but iron has no closed optical transition suitable for laser cooling. Fortunately Smeets and Te Sligte found that even then atom lithography of iron is possible. If the standing wave light field is considered to be an array of lenses, the focusing of the atom beam on a single lens is determined by the local collimation of the atom beam at that position. This local collimation is determined by the geometry of the beam source and the distance of the beam source to the standing wave lens. Using a small beam source (e.g. 1 mm diameter) positioned far from the standing wave (e.g. 1 m), the geometrically collimated atom beam is suitable for atom lithography. Chapter 3 shows what the implications of geometric collimation are on the structure formation in atom lithography. The geometric effects that locally collimate the atom beam on the sample also introduce local offset angles of the atom beam with respect to the focusing light field. Structure formation has been observed with lines of up to 7 nm high on a background layer of 15 nm average height, over areas of up to 400 µm × 6 mm. This indicates that the offset angles can vary over an 8 mrad range, which is more than an order of magnitude larger than the local angle of collimation. The offset angle influence the local geometry of the deposited structures: an increasing offset angle decreases the local line height, increases the width and creates a skewness in the local line shape. The local geometry of the lines has been modelled with a Monte Carlo particle tracking model and the results were compared to experiments. It was found that the highest and narrowest lines suffer from significant broadening due to surface diffusion in experiments, limiting the achievable structure width of iron on SiOx samples to about 80 nm. We have also found that in atom lithography without laser cooling, each standing wave lens is effectively imaging the source geometry onto the substrate. We therefore propose using structured atom beam sources to image more complex patterns on sub-wavelength scales in a parallel way. The reason to use iron in atom lithography, is the option to create magnetic nanostructures. However, in previous experiments no clear magnetic signature of the atom lithographic structuring of iron was found. Therefore in Chapter 4 firstly the magnetic properties of unstructured layers of iron (Fe), nickel (Ni) and FexNi1-x are investigated. These layers are all ferromagnetic, but with a reduced magnetic moment compared to bulk values due to contaminations and crystal growth effects. As a reference for periodic atom lithography structures, periodic line structures are created with interference lithography in a polymer layer and onto these structures thin layers of FexNi1-x are shadow deposited, thereby creating a layer periodically modulated in both height and elemental composition. This periodic modulation in composition has been observed with SEM-EDX on sub-micron scales. The structures showed a clear magnetic anisotropy with an easy axis along the direction of the lines, in accordance with expectations. In Chapter 5, the magnetic properties of atom lithographic iron line structures are presented. Using MOKE microscopy, direct comparison of structured and unstructured parts of a sample is possible, which allows for the observation of clear magnetic signatures due to the atom lithographic structuring. In layers of an average thickness of about 15 nm, no anisotropy is induced by the line structures, while a magnetic easy axis along the direction of the lines is expected. The line structures introduce an isotropic increase in the coercivity of the layers, indicating that the line structures can be considered as isotropic corrugations instead of directional line structures. For layers of 30 nm average thickness and thus higher line structures, a clear magnetic anisotropy is observed for the highest line structures. This anisotropy can be seen as a magnetic easy axis along the direction of the lines, as expected for line structures. However, we also observe a sharp increase in coercivity for applied fields perpendicular to the lines. This phenomenon is intriguing and may be explained by a pinning of head-to-head domain walls along the direction of the lines. In Chapter 5, we also report on the first results of co-deposition of FexNi1-x, where the Fe is structured into lines using atom lithography, while the Ni is deposited uniformly, thereby creating an alloy of modulating composition. Magnetic analysis of these structures indicates that these structures are anisotropic, both the coercivity and the shape of domain walls is dependent on the angle of the applied field relative to the line structures. Finally in Chapter 6, we investigate the possibilities to focus a thermal beam of atoms into a single 100 nm spot using light fields, thereby creating a nanopencil suitable for deposition of nanostructures. A Monte Carlo particle tracking program was developed to model the all optical focusing or funneling of 10 µm sized atom beams to a 100 nm spot. This model included effects of initial beam divergence, magnetic substructure, laser cooling, and spontaneous as well as stimulated diffusion and it was applied to a number of promising light field configurations. The best results obtained for experimentally realistic settings are a beam focused to a full width at half maximum of FWHM = 0.55 µm in a blue detuned hollow beam where atoms are focused towards the dark center, or a FWHM = 0.31 µm in a red detuned axicon light field, where atoms are focused towards the maximum intensity at the heart line. However, in the latter case the focused beam has a flux only 25 times larger than the background flux, which is unpractical for applications. The limiting factors of all schemes are heating due to stimulated diffusion and the limited interaction time available for a thermal beam of atoms. A nanopencil could be possible if it were based on the focussing of a slow and / or monochromatic atom beam, but this would seriously complicate the practical application of such a device.

Effective representation methods and proper signal priors are crucial in most signal processing applications. In this thesis we focus on different structured models and we design appropriate schemes that allow the discovery of low dimensional latent structures that characterise and identify the signals. Motivated by the highly non-linear structure of most datasets, we firstly investigate the geometry of manifolds. Manifolds are low dimensional, non-linear structures that are naturally employed to describe sets of strongly related signals such as the images of a 3-D object captured from different viewpoints. However, the use of manifolds in applications is not straightforward due to their usually non-analytic and non-linear form. We propose here a way to `disassemble' a manifold into simpler components by approximating it with affine subspaces. Our objective is to discover a set of low dimensional affine subspaces that can represent manifold data accurately while preserving the manifold's structure. To this end, we employ a greedy technique that iteratively merges manifold samples into groups based on the difference of local tangents. We use our algorithm to approximate synthetic and real manifolds and to demonstrate that it is competitive to state-of-the-art techniques. Then, we consider structured sparse representations of signals and we propose a new sparsity model, where signals are essentially composed of a small number of structured {\it molecules }. We define the molecules to be linear combinations of a small number of atoms in a redundant dictionary. Our multi-level model takes into account the energy distribution of the significant signal components in addition to their support. It permits to define typical visual patterns and recognise them in prototypical or deformed form. We define a new structural difference measure between molecules and their deformed versions, which is based on their sparse codes and we create an algorithm for decomposing signals into molecules that can account for different deviations in the internal molecule structure. Our experiments verify the benefits of the new image model in various restoration tasks and they confirm that the development of proper models that extend the mere notion of sparsity can be very useful for various inverse problems in imaging. Finally, we investigate the problem of learning molecule representations directly in the sparse code domain. We constrain sparse codes to be linear combinations of a few, possibly deformed, molecules and we design an algorithm that can learn the structure from the codes without transforming them back into the signal domain. To this end, we take advantage of our structural difference which is based on the sparse codes and we devise a scheme for representing the codes with molecules and learn the molecules at the same time. To illustrate the effectiveness of our proposed algorithm we apply it to various synthetic and real datasets and we compare the results with traditional sparse coding and dictionary learning techniques. From the experiments, we verify the superior performance of our scheme in interpreting and recognising correctly the underlying structure. In short, in this thesis we are interested in low-dimensional, structured models. Among the various choices, we focus on manifolds and sparse representations and we propose schemes that enhance their structural properties and highlight their effectiveness in signal representations.

The advent of gravitational wave (GW) astronomy has provided a new window through which to view and understand the Universe. To fully exploit the potential of GW astronomy, an understanding of all the potential electromagnetic counterparts to a gravitational wave detected source will help maximise the science returns. Here I present a study of the electromagnetic emission from relativistic jets that accompany the merger of binary neutron stars or black hole-neutron star systems. These counterparts provide a probe for the structure and dynamics of these relativistic outflows. Binary neutron star, or neutron star-black hole, mergers are thought to be the dominant progenitor of short gamma-ray bursts (GRBs). Here we investigate the possibility that there is a hidden population of low-Lorentz factor jets resulting in failed GRBs, on-axis orphan afterglows, and what kind of counterparts can be expected given a merger-jet population dominated by these failed-GRB jets. I find that for GW detected mergers, ∼ 80% of the population of on-axis events may result in a failed GRB afterglow. The afterglow of a failed GRB is characterised by the lack of any prompt emission; where the γ-rays are emitted within an optically thick region of the low-Lorentz factor (Γ) outflow and significant suppression via pair production and a high opacity results in the photons coupled to the pair plasma. This plasma will undergo adiabatic expansion, and the photons will decouple at the photospheric radius. The energy in the prompt photons, for a sufficiently low-Γ outflow, will have been significantly suppressed. GW detected mergers have a Malmquist bias towards on-axis events (i.e. the rotational axis of the system), where the peak of the probability distribution is an inclination ∼ 30⁰. If the jets from these mergers have an intrinsic structure out to wider angles, then the majority of mergers will be accompanied by electromagnetic counterparts from these various jet structures. By making some simple assumptions about the energetic structure of a jet outside of a bright core region, the various temporal features that result from a given jet structure can be predicted. Where the population of merger jets is dominated by a single structure model, I show the expected fractions of optical counterparts brighter than m_AB = 21. On 17 August 2017, the Light Interferometer Gravitational Wave Observatory (LIGO) in collaboration with Virgo detected the merger of a binary neutron star system. Various electromagnetic counterparts were detected: the GRB 170817A by Fermi/GBM and INTEGRAL; an optical, blue to red, macro/kilo-nova from ∼ 1/2 day post merger to ∼ 5 − 10 days; and a brightening radio, and X-ray counterpart from ∼ 10 days. Optical detection of this counterpart at a magnitude ∼ 26 was made at ∼ 100 days post-merger. Analysis of this counterpart is consistent with the afterglow of a Gaussian structured jet viewed at the system inclination, ∼ 18 ± 8⁰. If all short GRB jets have a similar jet structure, then the rates of orphan afterglows in deep drilling blind surveys e.g. the Large Synoptic Survey Telescope (LSST), will be higher than those expected from a homogeneous, or ‘top-hat’ jet, population. The rates for the various jet structures for orphan afterglows from mergers are discussed, showing that for a population of failed GRBs, or an intrinsic Gaussian structure, an excess in the orphan rate may be apparent. Understanding the dynamics and structure for the jets from black-hole systems born at the merger of a compact binary can help give clues as to the nature of jets from black holes on all scales. As an aside, I show empirically that regardless of black hole mass or system phenomenology, the relativistic jets from such systems share a universal scaling for the jet power and emitted γ-ray luminosity. This scaling could be due to the similar efficiencies of various processes, or alternatively, the scaling may be able to give insights into the emission and physical processes that are responsible for high-energy photons from these outflows. GW astronomy offers a probe of the most extreme relativistic outflows in the Universe, GRBs. The predicted electromagnetic counterparts from these outflows, in association with GW detections, provides a way to probe the Lorentz-factor distribution for merger-jets. Additionally, the phenomenological shape of the afterglows, at various inclinations, gives an indication of the intrinsic structure of these jets. An understanding of these dynamical and structural qualities can be used to constrain the parent population, merger rates, and binary evolution models for compact binary systems.

In this thesis, the spectral behavior of several classes of structured regular matrix pencils is studied under structure-preserving low-rank perturbations. Some of the principles that are proved are the following. For certain classes of structured matrix pencils, that have a symmetry in their spectrum, not all canonical forms are allowed when the matrix pencil is subjected to a structure-preserving low-rank perturbation. Therefore, for T -alternating, palindromic, Hermitian, symmetric, and skew-symmetric matrix pencils one observes the following effects at each eigenvalue λ under a generic, structure-preserving rank-1 or rank-2 perturbation: (a) The largest one or two, respectively, Jordan blocks at λ are destroyed. (b) If hereby the eigenvalue pairing imposed by the structure is violated, then also the largest remaining Jordan block at λ will grow in size by one. (c) If λ is a single (double) eigenvalue of the perturbing pencil, then one (two) new Jordan blocks of size one will be created at λ. Hermitian and real structured matrix pencils have signs attached to certain (real or purely imaginary) Jordan blocks in the canonical form, so it is not only the Jordan structure but also this so-called sign characteristic that needs to be examined under perturbation. If λ has a sign characteristic (otherwise the canonical form at λ is completely described by the previous paragraph), then the observed effects under a generic structure-preserving rank-1 or rank-2 perturbation are as follows: (a) All signs from the sign characteristic at λ but one or two, respectively, that correspond to the destroyed blocks, are preserved under perturbation. (b) If λ is not a semisimple eigenvalue of the original matrix pencil, then the sign of the potential new block at λ is prescribed to be the sign that is attached to the eigenvalue λ in the perturbation. Matrices that are structured with respect to an indefinite inner product will be studied under structure-preserving perturbations of arbitrary rank. ForH-selfadjoint, H-symmetric, and J-Hamiltonian matrices, the following results are proved: Let A be a matrix from one of these structure classes and let B be a matrix of rank k such that A+B is from the same structure class as A. Then, generically the Jordan structure and sign characteristic of A+ B is the same that one would obtain by performing a sequence of k generic structured rank-1 perturbations on A.

Individuals within fish populations differ in many traits, such as sex, life-history, habitat residence, diet, and morphology. Such trait differences among individuals (i.e. intra-population variation) may be greater than the differences among populations (i.e. inter-population variation). My dissertation examines intra-population variation, with a focus on trophic relationships and morphology; as well as how variation in these attributes may reflect differences in bioaccumulation of contaminants. The second chapter of my dissertation examines the influence of spatial-temporal variation on the trophic structures of round goby (Neogobius melanstomus) and two age classes of yellow perch (Perca flavescens) within Saginaw Bay, Lake Huron. Using stable isotope ratios (δ13C, δ15N, δ2H, δ18O) and stomach contents as trophic indicators, I examined variation of diets. I found that spatial variation had a greater impact on diet indicators than both annual and seasonal variation. This spatial variation could represent a form of compartmentalization within the community of fish residing in Saginaw Bay, and could provide stability to the community. Chapter three of my dissertation examines intra-population variation in yellow perch morphology through a series of mesocosm experiments. My first mesocosm study determined that yellow perch could be experimentally manipulated to display divergent morphologies using simulated habitats, specifically pelagic and littoral habitats. Following this experiment, I focused on specific environmental drivers (structure, prey resources, and predation risk) as possible influences on yellow perch morphology. Within experimental pools, I exposed yellow perch to one of four treatments (an open pool, a structured pool, pools with chironomid prey resources and pools with a perceived, olfactory, predation risk) in the summer of 2015. Following exposure to these treatments I examined the morphological changes in yellow perch in magnitude and direction. I observed that while each treatment induced some difference in morphology, the open and structured treatments had the greatest magnitude of difference. I repeated the open and structure treatments during the following summer (2016). Again, I found that structure and open morphologies could be induced by my mesocosm treatments, but also observed that shapes differed from the previous year’s structure and open treatments. Finally, my fourth chapter examined how variation in trophic niches and morphology may reflect variation in contaminant concentration of fish in their natural environment. In this chapter, I extended my work with yellow perch to also include black crappie (Pomoxis nigromaculatus) and examined fish from 5 northern Indiana glacial lakes. Using model inference techniques, I found that variation in mercury was closely associated with not only fish total length, but also stable isotopes (δ13C and δ15N) and morphology. Interestingly, morphology-related variables of both species were strong predictors of mercury concentration in fish, following total length. Together, the chapters within my dissertation highlight the importance of considering intra-population variation, in which local factors such as habitat conditions and prey availability can influence individual variation in trophic structuring and morphology. These in turn may reflect other attributes of interest, such as the accumulation of contaminants.

Polystyrene thin films containing Bragg structures have been successfully obtained by the removal of DBR porous silicon films from the DBR structured porous silicon/polystyrene composite film in HF/ mixture solution and by replicating the nano-structures of porous silicon containing Bragg structure. Polystyrene thin films containing Bragg structures displayed unique optical reflection resonances in optical reflection spectrum. This optical reflection band was resulted from the interference of reflection wavelength at Bragg structure of polystyrene thin films. The wavelength of reflection resonances could be modified by the change of Bragg structure of the master. Polystyrene thin films containing Bragg structures were flexible and maintained their optical characteristics upon bending. The Polystyrene thin films replicate the photonic features and the nanostructure of the master.

Interorganisational new service development capability in the mobile communications ecosystem

Owing to their high surface area, excellent electrolyte permeability and ample diffusion pathways for charge transport, porous and hollow-structured electrochemically active materials attract more attention as the electrodes. In general, the process of template preparation method is used to achieve hollow structured materials over the last few decades. However, the complicated preparation process including removal of template and surface modification often results in poor uniformity, low reproducibility, and high cost of porous structure. Moreover, it incorporates functional chemicals with specific homogeneity and dispersity into the hollow porous intercrystalline structure. These problems hinder the development and application in energy storage and conversion devices of the diversified porous and hollow-structured materials. The metal-organic frameworks (MOFs), consisting of organic linkers and coordinated inorganic clusters, appear as an excellent collection of porous crystal material series with high surface areas, high porosity, and tunable structures. However, their low conductivity and electrolyte instability limit the further use of MOFs in the field of LIBs. Recently, how electrode materials for Lithium–ion batteries (LIBs) are designed and prepare using MOFs has attracted more attention. The composite materials derived from MOFs including nanostructured porous carbons and metal oxide uaing self-sacrificial template synthetic route not only solves the problem of low conductivity but also maintains the high surface area and porous structure of MOFs, providing abundant active sites for insertion/deinsertion or adsorption/desorption; Furthermore, composite materials derived from MOFs increase the complexity of nanostructures in terms of structural units and chemical components. In particular, large pore volume and open pore structure are critical to loading guest species, accommodating mechanical strains and facilitating mass transport. In this paper, we briefly examined the production of MOF-derived materials for applications in LIBs. The optimization and modification of an MOFs morphology were implemented according to the electrode material requirement for LIBs. Moreover, the preparation of MOFs-derived electrode materials with porous, hollow, or complicated construction and their effects on electrochemical performance were described. Finally, the challenge and trend in production of electrode materials derived from MOFs were analyzed.

Ecological studies indicate that structurally complex habitats support elevated biodiversity, stability and resilience. The long-term persistence of structured habitats and their importance in maintaining biodiverse hotspots remain underexplored. We combined geohistorical data (dead molluscs, ‘DA’) and contemporary surveys (live molluscs, ‘LA’) to assess the persistence of local seagrass habitats over multi-centennial timescales and to evaluate whether they acted as long-term drivers of biodiversity, stability and resilience of associated fauna. We sampled structured seagrass meadows and open sandy bottoms along Florida's Gulf Coast. Results indicated that (i) LA composition differed significantly between the two habitat types, (ii) LA from seagrass sites were characterized by significantly elevated local biodiversity and significantly higher spatial stability, (iii) DA composition differed significantly between the two habitat types, and (iv) fidelity between LA and DA was significantly greater for seagrass habitats. Contemporary results support the hypotheses that local biodiversity and spatial stability of marine benthos are both elevated in structured seagrass habitats. Geohistorical results suggest that structured habitats persist as local hotspots of elevated biodiversity and faunal stability over centennial-to-millennial timescales; indicating that habitat degradation and concomitant loss within structurally complex marine systems is a key driver of declining biodiversity and resilience.

In bacterial genomes a fraction of transcribed sequences do not code for proteins or structural RNAs, but have been shown to be involved in fundamental processes, such as regulation of gene expression, mRNA processing and stability or structural RNA maturation. In this thesis a systematic procedure to identify and classify families of repeated sequences sharing a common RNA secondary structure was applied to the study of 40 bacterial genomes. Sequences able to fold in a stable stem loop structure were clustered according to sequence similarity, and grouped within homogeneous families. The study led to the identification of 57 families of repeated sequences, sharing a common secondary structure and potentially coding for structured RNAs. All previously known such families have been detected by the used procedure, and are listed within the final set, together with 37 novel ones. Their location in relation to protein coding genes was evaluated, and a correlation was found between structure and positioning within intergenic regions. A new software tool is also described, Scaffolder, designed to help in high-throughput de novo genome sequencing by finding connections between contigs produced by random shotgun sequencing, and assisting the researcher in the whole process. The software, accessible both as a command line tool and as a web application, can guide all the final phases of genome assembly by storing the current assembly status, displaying networks of connected contigs and untangling multiply connected ones by a combination of computational and experimental procedures.

United States of America is a country that has a decentralized management system and federal form of government structure. Management system offers three tiered structure. Federal government is in the first level of administrative unit, states are in the second level of administrative units and local governments are the third level of administrative unit. Local government’s structure and quality varies from state to state. Therefore, each local government unit has its own unique features. Local governments in the USA can be classified in the form of county, municipal, town and village, school districts and special districts. However, sometimes a local government unit that has the same structure is also structured with a different name in another state. In this paper, management structure of USA, local government’s financial structure and its relationship with the central government have been examined.

Urbanization is characterized by rapid intensification of agriculture, socioeconomic change, and ecological fragmentation, which can have profound impacts on the distributional ecology of host populations and epidemiology of infectious disease within them. In this thesis, results from a large-scale field study conducted in Nairobi, Kenya are used to explore how anthropogenic and ecological changes associated with urbanisation influence the structure of sympatric wildlife, livestock and human host populations, and dictate bacterial epidemiology in wildlife hosts. As likely points of contact (and thus parasite transmission) between vertebrate wildlife, livestock, and humans, household ‘interfaces’ were chosen as sampling units. The ecological and sociological status of households was characterised through ecological surveys, questionnaire data and geospatial mapping, and faecal samples were collected from wildlife occurring within the household compound, and livestock and human inhabitants. Escherichia coli was isolated from faecal samples, and characterised both phenotypically (through antimicrobial sensitivity testing) and genetically (through whole genome sequencing). In the first part of this thesis I consider the influence of urban land-use change on the structure of host populations at household interfaces. Using unsupervised machine learning I describe variation in the host composition of wildlife-livestockhuman interfaces and, through multivariate regression analysis, demonstrate that citywide variation in ecological and anthropogenic factors (such as biotic habitat diversity and wealth) drive structural changes in wildlife, livestock and human populations across the urban landscape of Nairobi. Utilising commensal E. coli as an exemplar organism, I proceed to explore epidemiological connectivity between wildlife, livestock and humans at household interfaces, and link epidemiological processes in urban wildlife to their drivers across the urban landscape. Firstly, I explore the epidemiology of clinically relevant antimicrobial resistant (AMR)-E. coli in urban wildlife in Nairobi. Comparing E. coli isolates in wildlife to livestock, humans and the environment, I find that E. coli isolated from wildlife have a lower diversity of resistance phenotypes, and are thus an unlikely source of AMR. At household interfaces, I find evidence of AMR-E. coli exchange between rodents/seed-eating birds, and cattle and humans, and demonstrate that transmission is facilitated through anthropogenic resource provision in households. Next, utilising high resolution sequencing data, I explore the response of microbial communities in wildlife hosts to urban land-use change. Specifically, I test the hypothesis that communities of bacterial mobile genetic elements (MGEs) are deterministically structured, according to changes in host community structure. I show that the diversity of genes encoding virulence and AMR in avian-borne E. coli is determined by variation in the distribution and density of birds, livestock and humans at household interfaces, and that this varies along gradients of urbanisation. To conclude, I relate the findings in this thesis across multiple scales, linking the influence of abiotic factors such as habitat alteration and socioeconomics to host community structure at household interfaces and the epidemiology of wildlife-borne E. coli. Using this framework, I suggest future directions for research on urban disease emergence, and discuss implications of my findings for public health and urban planning.

The paper proposes critical summary of the current data on fireplaces, ovens and furnaces identified in protohistoric Sardinia archaeological contexts between the Middle Bronze Age and the Early Iron Age. The aim of the research is to offer a reflection both on the quantity and quality of data in order to the use of fire in archaeological contexts, and on the difficulties about to their recognition and to the related functional interpretation. The analysis was carried out on the basis of an updated repertory, including all the published evidence, with the aim of proposing the typological classification of combustion structures and of determining their features also in relation to the different areas of reference. It was necessary to identify a criterion for pyrotechnic structures classification that would take into account the type of context, morphology and, when possible, function. Traces of fire use have been identified in the archaeological stratifications, in more or less structured spaces and coinciding with different monumental evidences such as nuraghi, village areas, cultural complexes. In correspondence with these areas, within domestic, cultural or uncertain destination spaces, there are fireplaces and points of fire with widely varied structuring methods. Both combustion zones of different shapes and sizes without delimitation elements and structured hearths, defined by lithic elements, characterized by different levels of finishing and complexity, can be recognized. Ovens and furnaces are not well documented in quantitative terms but are better defined for their typological characteristics. The functional aspects have been examined through the recognition of indicators such as associated artifacts or other elements derived from the specific context and the spatial location of structures related to pyrotechnic activities.

شاهنامه طرحی انداموار و یکپارچه دارد و اگر هم دارای دو بخش اسطوره‌ای و تاریخی است، این دو بخش به هم پیوسته هستند: بخش اسطوره‌ای به آفرینش و بخش تاریخی به تداوم آن توجه دارد. یکی از انگیزه‌های بنیادی در تدوین شاهنامه، احیای هویت ایرانی بوده است. همین مسألة احیای هویت موجب شده شاهنامه جایگاه حماسة ملی بیابد و از همان آغاز محتوایی پیدا کند که با تکیه بر مسائل فرهنگی، رسالتی سیاسی را دنبال می‌کند. مبنای فرهنگی شاهنامه عبارت است از نبرد اهورامزدا و اهریمن؛ چنین مبنایی هم توجیه چگونگی آفرینش و هم تداوم‌بخش زندگی جمعی است و هرگونه بازاندیشی در پیوند آفرینش با تداوم حیات به پدیدار شدن الگویی سیاسی می‌انجامد؛ نمونه‌های نخستین انسان به شاهان آغازین و الگوهای پادشاهی بدل می‌شوند و نبرد از اهورا و اهریمن به نمایندگان آن ها منتقل می‌شود و خویشکاری انسان را تجلی می‌بخشد. در بخش اسطوره‌ای، ایرانیان شکلی ابتدائی از حکومت را طرح کرده‌اند و آن را در گزینه‌های متعددی گنجانده‌اند تا به الگوی مناسبی برای حکومت دست یابند. وقتی به الگوی مناسب دست یافته‌اند آن را آرمان خود کرده‌اند؛ پس از آن در بخش تاریخی، برایش در پی جایگزینی واقعی برآمده‌اند.