An extensive laboratory investigation of the use of bio-oil modified bitumen in road construction

Several roads in Iceland with bio-oil modified surface dressings exhibited severe distresses such as bleeding, binder drain down, and eventually as surface dressing sticking to tires. Samples from six road sections were evaluated in the laboratory to determine the causes of the failure. Binders with and without bio-oil, rapeseed oil and fish oil, were evaluated through a comprehensive rheological and chemical characterization. Both oils, exhibited solubility issues with the bitumen; consequently, the oils covered the aggregates, preventing bonding between binder and stones. It appears that fish oil worked a little better than rapeseed oil for binder modification.

Experiments on the generation of activated carbon from biomass

Activated carbon is generated from various waste biomass sources like rice straw, wheat straw, wheat straw pellets, olive stones, pistachios shells, walnut shells, beech wood and hardcoal. After drying the biomass is pyrolysed in the temperature range of 500-600 °C at low heating rates of 10 K/min. The activation of the chars is performed as steam activation at temperatures between 800 °C and 900 °C. Both the pyrolysis and activation experiments were run in lab-scale facilities. It is shown that nut shells provide high active surfaces of 1000-1300 m/g whereas the active surface of straw matters does hardly exceed 800 m/g which might be a result of the high ash content of the straws and the slightly higher carbon content of the nut shells. The active surface is detected by BET method. Besides the testing of a many types of biomass for the suitability as base material in the activated carbon production process, the experiments allow for the determination of production parameters like heating rate and pyrolysis temperature, activation time and temperature as well as steam flux which are necessary for the scale up of the process chain. © 2006 Elsevier B.V. All rights reserved.

The Blue Highway

The Blue Highway is a collection of eleven literary short stories and ten miniatures that depict men in trouble, searching for a code to live by. The miniatures are repressed memories, appearing suddenly like the tips of ice bergs and act as stepping stones (tension bridges) between the larger works. The stories begin at the end with "Time Out", the story of Frank, a down and out homeless vet at the end of his rope. Then we begin the journey along "The Blue Highway" with Danny and his gang of teenage bandits, taking themselves to Disney World to see if they can recapture their lost dream. On our journey we will meet Mark, the ex-killer, an old Cuban fisherman who will not give up his honor, a young man on a way to a war who discovers a fantastic treasure, a soldier on his way home again, two MP's who nearly kill the wrong man, we will spend a night on an African savannah with wild hyenas and finally, meet a grandfather who discovers the one gift which might save his family. The same gift which might save Frank as well. ^

La ciudad, el poeta y su familia melancolica (Poesia Chilena de los ultimos 50 anos)

This dissertation explored the relationship among poets, cities, and the construction of nation-ness. It was an interpretive reading of Chilean poetry and Chilean-ness as a way of inventing the nation from its very origins, starting with the colonial epic poem La Araucana and the founding of Santiago, its capital city. In this dissertation, poetry not only dealt with cities or "city poets" but also with the very conception, drafting, and systematic invention of cities as a "dream of order". The construct of a "community" of Chileans has maintained family ties with "Melancholy" in the collective imagination. This structure of melancholy reinforced the idea of "an order and a community" passed along by poets through generations. This dissertation also explored the moment when this melancholic family was fractured, divided, and Santiago was darkened by the events of September 11, 1973 and the rise of dictatorship, brutality, and censorship. ^ The methodology employed to examine different aspects of the construction of the city-nation included theoretical approaches such as Benedict Anderson's idea of nations as "imagined communities," Ángel Rama's analysis of Latin American urban rationality in his book The Lettered City , and the idea of the poet as an urban seer or visionary, the "flâneur" studied by Walter Benjamin in Charles Baudelaire's poetry. A central finding was that this "imagined community" have been severely transformed since 1950. In Chilean poetry, two works served as major referents: Pablo Neruda's Canto General, a totalizing idea of collective identity carved from the stones of the ruins of Machu Picchu, and Nicanor Parra's Poemas y Antipoemas (1954), which begun to illustrate the slow "decomposition" of the "The Lettered City." Among such conflicting images of (post-)modernity, poet Enrique Lihn became the central counter-figure who put an end to a long tradition of producing canonical nation-building cultural artifacts. His book El paseo Ahumada (1983) impacted the new generations of Chilean poets. The conclusion brought together the five-century history and diverse poetic experiences of the traditional Lettered City with the latest currents of marginalized urban poetry (1987-2003), the so-called "barbarians," flâneurs who were (re)inventing Chilean-ness in the globalized, and anti-Utopian city of "Sanhattan." ^

The political economy of poverty alleviation strategies. The initiative for heavily indebted poor countries in Bolivia: More of the same

In the year 2000, approximately 1.1 billion people lived in extreme poverty while developed countries spent US$600 billion a year on defense. The Heavily Indebted Poor Countries (HIPC) Initiative is a recent component of a larger poverty reduction strategy supported by the International Financial Institutions, as well as many developed and developing countries. By implementing lessons of the past fifty years, this program attempts to diminish misery around the globe. As such, it provides debt relief while seeking to enable the poorest countries to simultaneously attain sustainable debt and promote human development. Interest in poverty reduction around the globe reemerged in the 1990s. This study contributes directly to this recent effort by presenting a nuanced approach that builds on the stepping-stones generated by other poverty scholars. To fulfill its goal, this investigation applies a political economy framework. Within this framework, the author conducts an actor-specific analysis. This dissertation addresses the following question: How do domestic and international actors respond to the implementation of poverty alleviation strategies? The author assumes actors desire to maximize their utility calculation and suggests these calculations are based on the player's motivations and external influences. Based on their motivations, the external influences, and the initiative's guidelines, each actor develops a set of expectations. To fulfill those expectations, stake holders utilize one or several strategies. Finally, the actors' ability to achieve their expectations determines each player's assessment of the initiative. The framework described is applied in an in-depth, actor-specific analysis of the HIPC in Bolivia. Bolivia's National Revolution represents the country's first attempt at reducing poverty. Since then, all governments have taken specific steps to combat poverty at the local and national levels. The Initiative for Heavily Indebted Poor Countries (HIPC) is one of the most recent macro strategies of this kind. The case study demonstrated that three factors (national ownership, effective sponsorship and the local context) determine the success levels of poverty reduction strategies from abroad. In addition, the investigation clearly shows that poverty reduction is not the sole motivation in the implementation of poverty alleviation strategies. All actors, however, share the dream of poverty reduction.

Increased rate of cholecystectomies performed with doubtful or no indications after laparoscopy introduction: a single center experience

Background During recent years laparoscopic cholecystectomy has dramatically increased, sometimes resulting in overtreatment. Aim of this work was to retrospectively analyze all laparoscopic cholecystectomies performed in a single center in order to find the percentage of patients whose surgical treatment may be explained with this general trend, and to speculate about the possible causes. Methods 831 patients who underwent a laparoscopic cholecystectomy from 1999 to 2008 were retrospectively analyzed. Results At discharge, 43.08% of patients were operated on because of at least one previous episode of biliary colic before the one at admission; 14.08% of patients presented with acute lithiasic cholecystitis; 14.68% were operated on because of an increase in bilirubin level; 1.56% were operated on because of a previous episode of jaundice with normal bilirubin at admission; 0.72% had gallbladder adenomas, 0.72% had cholangitis, 0.36% had biliodigestive fistula and one patient (0.12%) had acalculous cholecystitis. By excluding all these patients, 21.18% were operated on without indications. Conclusions The broadening of indications for laparoscopic cholecystectomy is undisputed and can be considered a consequence of new technologies that have been introduced, increased demand from patients, and the need for practice by inexperienced surgeons. If not prevented, this trend could continue indefinitely.

The blue highway

The Blue Highway is a collection of eleven literary short stories and ten miniature that depict men in trouble, searching for a code to live by. The miniatures are repressed memories, appearing suddenly like the tips of ice bergs and act as stepping stones (tension bridges) between the larger works. The stories begin at the end with "Time Out", the story of Frank, a down and out homeless vet at the end of his rope. Then we begin the journey along "The Blue Highway" with Danny and his gang of teenage bandits, taking themselves to Disney World to see if they can recapture their lost dream. On our journey we will meet Mark, the ex-killer, an old Cuban fisherman who will not give up his honor, a young man on a way to a war who discovers a fantastic treasure, a soldier on his way home again, two MP's who nearly kill the wrong man, we will spend a night on an African savannah with wild hyenas and finally, meet a grandfather who discovers the one gift which might save his family. The same gift which might save Frank as well.

Macroinvertebrate abundance in montane tropical streams of varying land-use, Ecuador

Despite the importance of tropical montane cloud forest streams, studies investigating aquatic communities in these regions are rare and knowledge on the driving factors of community structure is missing. The objectives of this study therefore were to understand how land-use influences habitat structure and macroinvertebrate communities in cloud forest streams of southern Ecuador. We evaluated these relationships in headwater streams with variable land cover, using multivariate statistics to identify relationships between key habitat variables and assemblage structure, and to resolve differences in composition among sites. Results show that shading intensity, substrate type and pH were the environmental parameters most closely related to variation in community composition observed among sites. In addition, macroinvertebrate density and partly diversity was lower in forested sites, possibly because the pH in forested streams lowered to almost 5 during spates. Standard bioindicator metrics were unable to detect the changes in assemblage structure between disturbed and forested streams. In general, our results indicate that tropical montane headwater streams are complex and heterogeneous ecosystems with low invertebrate densities. We also found that some amount of disturbance, i.e. patchy deforestation, can lead at least initially to an increase in macroinvertebrate taxa richness of these streams.

Quintosana e seus derivados conjugados com ácido gálico: avaliação de seu potencial antioxidante e de interferência na formação de cristais de oxalato de cálcio

Chitin is the second most abundant polysaccharide in nature and its derivative chitosan has been widely studied due to its unique chemical and pharmacological properties. However, studies show that when this molecule is used as food, drug, etc. it tends to accumulate in renal tissue and promotes an increase in calcium excretion. Nevertheless, the effect of chitosan on the formation of calcium oxalate (OxCa) crystals has never been evaluated. The formation of kidney stones (urolithiasis) is the disease that most often affects the kidneys and the urinary system. In addition, this is a disease with high prevalence and recurrence. Many molecules with antioxidant activity have been shown to decrease the potential for in vitro OxCa crystals formation. Thus, the aim of this study was to evaluate the effect of low molecular weight chitosan and its derivatives conjugated to gallic acid (AG) as antioxidant and inhibitor of OxCa crystals formation. The physico-chemical analysis confirmed the identity of chitosan. This molecule was subjected to five antioxidant tests and showed an excellent copper chelating activity. However, chitosan did not show other significant antioxidant activity. When chitosan was subjected to in vitro crystal formation tests, it increased the number of OxCa monohydrate crystals, modified the morphology of the crystals, modified the proportions between populations of crystals in solution and increased the zeta potential of these crystals formed. Four molecules of chitosan conjugated with GA were obtained. The physico-chemical analysis confirmed that chitosan and AG were covalently bonded. However, the amount of GA liked to chitosan did not increase even when 10 times more GA was used in experiment. When these derivatives were subjected to antioxidant tests, all chitosan conjugates showed higher antioxidant potential than their precursors. However, they showed different activity between them, which indicating that the position where AG is conjugated is an important factor for chitosan-GA activity. When conjugated chitosans were submitted to in vitro crystal formation tests, a reduction in the crystals number was observed when compared with those formed in the presence of unconjugated chitosan. Chitosan has a strong capacity for inducing OxCa monohydrate crystal formation, as well as modify their morphology and zeta potential. Over all, the process of conjugating AG to chitosan led to an increase in antioxidant potential of this molecule and was also able to decrease its capacity of inducing in vitro crystal formation

Ostracode relative abundances and geochemistry in surface sediments from Lake Ohrid

Understanding the ecology of bioindicators such as ostracods is essential in order to reconstruct past environmental and climate change from analysis of fossil assemblages preserved in lake sediment cores. Knowledge of the ecology of ancient Lake Ohrid's ostracod fauna is very limited and open to debate. In advance of the Ohrid ICDP-Drilling project, which has potential to generate high-resolution long-term paleoenvironmental data of global importance in paleoclimate research, we sampled Lake Ohrid and a wide range of habitat types in its surroundings to assess 1) the composition of ostracod assemblages in lakes, springs, streams, and short-lived seasonal water bodies, 2) the geographical distribution of ostracods, and 3) the ecological characteristics of individual ostracod species. In total, 40 species were collected alive, and seven species were preserved as valves and empty carapaces. Of the 40 ostracod species, twelve were endemic to Lake Ohrid. The most common genus in the lake was Candona, represented by 13 living species, followed by Paralimnocythere, represented by five living species. The most frequent species was Cypria obliqua. Species with distinct distributions included Heterocypris incongruens, Candonopsis kingsleii, and Cypria lacustris. The most common species in shallow, flooded areas was H. incongruens, and the most prominent species in ditches was C. kingsleii. C. lacustris was widely distributed in channels, springs, lakes, and rivers. Statistical analyses were performed on a "Lake Ohrid" dataset, comprising the subset of samples from Lake Ohrid alone, and an "entire" dataset comprising all samples collected. The unweighted pair group mean average (UPGMA) clustering was mainly controlled by species-specific depth preferences. Canonical Correspondence Analysis (CCA) with forward selection identified water depth, water temperature, and pH as variables that best explained the ostracod distribution in Lake Ohrid. The lack of significance of conductivity and dissolved oxygen in CCA of Ohrid data highlight the uniformity across the lake of the well-mixed waters. In the entire area, CCA revealed that ostracod distribution was best explained by water depth, salinity, conductivity, pH, and dissolved oxygen. Salinity was probably selected by CCA due to the presence of Eucypris virens and Bradleystrandesia reticulata in short-lived seasonal water bodies. Water depth is an important, although indirect, influence on ostracod species distribution which is probably associated with other factors such as sediment texture and food supply. Some species appeared to be indicators for multiple environmental variables, such as lake level and water temperature.

Recent developments in computed tomography for urolithiasis: diagnosis and characterization.

Objective. To critically evaluate the current literature in an effort to establish the current role of radiologic imaging, advances in computed tomography (CT) and standard film radiography in the diagnosis, and characterization of urinary tract calculi. Conclusion. CT has a valuable role when utilized prudently during surveillance of patients following endourological therapy. In this paper, we outline the basic principles relating to the effects of exposure to ionizing radiation as a result of CT scanning. We discuss the current developments in low-dose CT technology, which have resulted in significant reductions in CT radiation doses (to approximately one-third of what they were a decade ago) while preserving image quality. Finally, we will discuss an important recent development now commercially available on the latest generation of CT scanners, namely, dual energy imaging, which is showing promise in urinary tract imaging as a means of characterizing the composition of urinary tract calculi.

Advanced Techniques for Image Quality Assessment of Modern X-ray Computed Tomography Systems

X-ray computed tomography (CT) imaging constitutes one of the most widely used diagnostic tools in radiology today with nearly 85 million CT examinations performed in the U.S in 2011. CT imparts a relatively high amount of radiation dose to the patient compared to other x-ray imaging modalities and as a result of this fact, coupled with its popularity, CT is currently the single largest source of medical radiation exposure to the U.S. population. For this reason, there is a critical need to optimize CT examinations such that the dose is minimized while the quality of the CT images is not degraded. This optimization can be difficult to achieve due to the relationship between dose and image quality. All things being held equal, reducing the dose degrades image quality and can impact the diagnostic value of the CT examination.

A recent push from the medical and scientific community towards using lower doses has spawned new dose reduction technologies such as automatic exposure control (i.e., tube current modulation) and iterative reconstruction algorithms. In theory, these technologies could allow for scanning at reduced doses while maintaining the image quality of the exam at an acceptable level. Therefore, there is a scientific need to establish the dose reduction potential of these new technologies in an objective and rigorous manner. Establishing these dose reduction potentials requires precise and clinically relevant metrics of CT image quality, as well as practical and efficient methodologies to measure such metrics on real CT systems. The currently established methodologies for assessing CT image quality are not appropriate to assess modern CT scanners that have implemented those aforementioned dose reduction technologies.

Thus the purpose of this doctoral project was to develop, assess, and implement new phantoms, image quality metrics, analysis techniques, and modeling tools that are appropriate for image quality assessment of modern clinical CT systems. The project developed image quality assessment methods in the context of three distinct paradigms, (a) uniform phantoms, (b) textured phantoms, and (c) clinical images.

The work in this dissertation used the “task-based” definition of image quality. That is, image quality was broadly defined as the effectiveness by which an image can be used for its intended task. Under this definition, any assessment of image quality requires three components: (1) A well defined imaging task (e.g., detection of subtle lesions), (2) an “observer” to perform the task (e.g., a radiologists or a detection algorithm), and (3) a way to measure the observer’s performance in completing the task at hand (e.g., detection sensitivity/specificity).

First, this task-based image quality paradigm was implemented using a novel multi-sized phantom platform (with uniform background) developed specifically to assess modern CT systems (Mercury Phantom, v3.0, Duke University). A comprehensive evaluation was performed on a state-of-the-art CT system (SOMATOM Definition Force, Siemens Healthcare) in terms of noise, resolution, and detectability as a function of patient size, dose, tube energy (i.e., kVp), automatic exposure control, and reconstruction algorithm (i.e., Filtered Back-Projection– FPB vs Advanced Modeled Iterative Reconstruction– ADMIRE). A mathematical observer model (i.e., computer detection algorithm) was implemented and used as the basis of image quality comparisons. It was found that image quality increased with increasing dose and decreasing phantom size. The CT system exhibited nonlinear noise and resolution properties, especially at very low-doses, large phantom sizes, and for low-contrast objects. Objective image quality metrics generally increased with increasing dose and ADMIRE strength, and with decreasing phantom size. The ADMIRE algorithm could offer comparable image quality at reduced doses or improved image quality at the same dose (increase in detectability index by up to 163% depending on iterative strength). The use of automatic exposure control resulted in more consistent image quality with changing phantom size.

Based on those results, the dose reduction potential of ADMIRE was further assessed specifically for the task of detecting small (<=6 mm) low-contrast (<=20 HU) lesions. A new low-contrast detectability phantom (with uniform background) was designed and fabricated using a multi-material 3D printer. The phantom was imaged at multiple dose levels and images were reconstructed with FBP and ADMIRE. Human perception experiments were performed to measure the detection accuracy from FBP and ADMIRE images. It was found that ADMIRE had equivalent performance to FBP at 56% less dose.

Using the same image data as the previous study, a number of different mathematical observer models were implemented to assess which models would result in image quality metrics that best correlated with human detection performance. The models included naïve simple metrics of image quality such as contrast-to-noise ratio (CNR) and more sophisticated observer models such as the non-prewhitening matched filter observer model family and the channelized Hotelling observer model family. It was found that non-prewhitening matched filter observers and the channelized Hotelling observers both correlated strongly with human performance. Conversely, CNR was found to not correlate strongly with human performance, especially when comparing different reconstruction algorithms.

The uniform background phantoms used in the previous studies provided a good first-order approximation of image quality. However, due to their simplicity and due to the complexity of iterative reconstruction algorithms, it is possible that such phantoms are not fully adequate to assess the clinical impact of iterative algorithms because patient images obviously do not have smooth uniform backgrounds. To test this hypothesis, two textured phantoms (classified as gross texture and fine texture) and a uniform phantom of similar size were built and imaged on a SOMATOM Flash scanner (Siemens Healthcare). Images were reconstructed using FBP and a Sinogram Affirmed Iterative Reconstruction (SAFIRE). Using an image subtraction technique, quantum noise was measured in all images of each phantom. It was found that in FBP, the noise was independent of the background (textured vs uniform). However, for SAFIRE, noise increased by up to 44% in the textured phantoms compared to the uniform phantom. As a result, the noise reduction from SAFIRE was found to be up to 66% in the uniform phantom but as low as 29% in the textured phantoms. Based on this result, it clear that further investigation was needed into to understand the impact that background texture has on image quality when iterative reconstruction algorithms are used.

To further investigate this phenomenon with more realistic textures, two anthropomorphic textured phantoms were designed to mimic lung vasculature and fatty soft tissue texture. The phantoms (along with a corresponding uniform phantom) were fabricated with a multi-material 3D printer and imaged on the SOMATOM Flash scanner. Scans were repeated a total of 50 times in order to get ensemble statistics of the noise. A novel method of estimating the noise power spectrum (NPS) from irregularly shaped ROIs was developed. It was found that SAFIRE images had highly locally non-stationary noise patterns with pixels near edges having higher noise than pixels in more uniform regions. Compared to FBP, SAFIRE images had 60% less noise on average in uniform regions for edge pixels, noise was between 20% higher and 40% lower. The noise texture (i.e., NPS) was also highly dependent on the background texture for SAFIRE. Therefore, it was concluded that quantum noise properties in the uniform phantoms are not representative of those in patients for iterative reconstruction algorithms and texture should be considered when assessing image quality of iterative algorithms.

The move beyond just assessing noise properties in textured phantoms towards assessing detectability, a series of new phantoms were designed specifically to measure low-contrast detectability in the presence of background texture. The textures used were optimized to match the texture in the liver regions actual patient CT images using a genetic algorithm. The so called “Clustured Lumpy Background” texture synthesis framework was used to generate the modeled texture. Three textured phantoms and a corresponding uniform phantom were fabricated with a multi-material 3D printer and imaged on the SOMATOM Flash scanner. Images were reconstructed with FBP and SAFIRE and analyzed using a multi-slice channelized Hotelling observer to measure detectability and the dose reduction potential of SAFIRE based on the uniform and textured phantoms. It was found that at the same dose, the improvement in detectability from SAFIRE (compared to FBP) was higher when measured in a uniform phantom compared to textured phantoms.

The final trajectory of this project aimed at developing methods to mathematically model lesions, as a means to help assess image quality directly from patient images. The mathematical modeling framework is first presented. The models describe a lesion’s morphology in terms of size, shape, contrast, and edge profile as an analytical equation. The models can be voxelized and inserted into patient images to create so-called “hybrid” images. These hybrid images can then be used to assess detectability or estimability with the advantage that the ground truth of the lesion morphology and location is known exactly. Based on this framework, a series of liver lesions, lung nodules, and kidney stones were modeled based on images of real lesions. The lesion models were virtually inserted into patient images to create a database of hybrid images to go along with the original database of real lesion images. ROI images from each database were assessed by radiologists in a blinded fashion to determine the realism of the hybrid images. It was found that the radiologists could not readily distinguish between real and virtual lesion images (area under the ROC curve was 0.55). This study provided evidence that the proposed mathematical lesion modeling framework could produce reasonably realistic lesion images.

Based on that result, two studies were conducted which demonstrated the utility of the lesion models. The first study used the modeling framework as a measurement tool to determine how dose and reconstruction algorithm affected the quantitative analysis of liver lesions, lung nodules, and renal stones in terms of their size, shape, attenuation, edge profile, and texture features. The same database of real lesion images used in the previous study was used for this study. That database contained images of the same patient at 2 dose levels (50% and 100%) along with 3 reconstruction algorithms from a GE 750HD CT system (GE Healthcare). The algorithms in question were FBP, Adaptive Statistical Iterative Reconstruction (ASiR), and Model-Based Iterative Reconstruction (MBIR). A total of 23 quantitative features were extracted from the lesions under each condition. It was found that both dose and reconstruction algorithm had a statistically significant effect on the feature measurements. In particular, radiation dose affected five, three, and four of the 23 features (related to lesion size, conspicuity, and pixel-value distribution) for liver lesions, lung nodules, and renal stones, respectively. MBIR significantly affected 9, 11, and 15 of the 23 features (including size, attenuation, and texture features) for liver lesions, lung nodules, and renal stones, respectively. Lesion texture was not significantly affected by radiation dose.

The second study demonstrating the utility of the lesion modeling framework focused on assessing detectability of very low-contrast liver lesions in abdominal imaging. Specifically, detectability was assessed as a function of dose and reconstruction algorithm. As part of a parallel clinical trial, images from 21 patients were collected at 6 dose levels per patient on a SOMATOM Flash scanner. Subtle liver lesion models (contrast = -15 HU) were inserted into the raw projection data from the patient scans. The projections were then reconstructed with FBP and SAFIRE (strength 5). Also, lesion-less images were reconstructed. Noise, contrast, CNR, and detectability index of an observer model (non-prewhitening matched filter) were assessed. It was found that SAFIRE reduced noise by 52%, reduced contrast by 12%, increased CNR by 87%. and increased detectability index by 65% compared to FBP. Further, a 2AFC human perception experiment was performed to assess the dose reduction potential of SAFIRE, which was found to be 22% compared to the standard of care dose.

In conclusion, this dissertation provides to the scientific community a series of new methodologies, phantoms, analysis techniques, and modeling tools that can be used to rigorously assess image quality from modern CT systems. Specifically, methods to properly evaluate iterative reconstruction have been developed and are expected to aid in the safe clinical implementation of dose reduction technologies.

ThreeDimensional Epigraphic Recording at Stobi (Former Yugoslav Republic of Macedonia): Creating a Virtual Lapidarium

There is an increased need for 3D recording of archaeological sites and digital preservation of their artifacts. Digital photogrammetry with prosumer DSLR cameras is a suitable tool for recording epigraphy in particular, as it allows for the recording of inscribed surfaces with very high accuracy, often better than 2 mm and with only a short time spent in the field. When photogrammetry is fused with other computational photography techniques like panoramic tours and Reflectance Transformation Imaging, a workflow exists to rival traditional LiDAR­based methods. The difficulty however, arises in the presentation of 3D data. It requires an enormous amount of storage and end­user sophistication. The proposed solution is to use game­engine technology and high definition virtual tours to provide not only scholars, but also the general public with an uncomplicated interface to interact with the detailed 3D epigraphic data. The site of Stobi, located near Gradsko, in the Former Yugoslav Republic of Macedonia (FYROM) was used as a case study to demonstrate the effectiveness of RTI, photogrammetry and virtual tour imaging working in combination. A selection of nine sets of inscriptions from the archaeological site were chosen to demonstrate the range of application for the techniques. The chosen marble, sandstone and breccia inscriptions are representative of the varying levels of deterioration and degradation of the epigraphy at Stobi, in which both their rates of decay and resulting legibility is varied. This selection includes those which are treated and untreated stones as well as those in situ and those in storage. The selection consists of both Latin and Greek inscriptions with content ranging from temple dedication inscriptions to statue dedications. This combination of 3D modeling techniques presents a cost and time efficient solution to both increase the legibility of severely damaged stones and to digitally preserve the current state of the inscriptions.