Omnidirectional Depth Computation from a Single Image

Omnidirectional cameras offer a much wider field of view than the perspective ones and alleviate the problems due to occlusions. However, both types of cameras suffer from the lack of depth perception. A practical method for obtaining depth in computer vision is to project a known structured light pattern on the scene avoiding the problems and costs involved by stereo vision. This paper is focused on the idea of combining omnidirectional vision and structured light with the aim to provide 3D information about the scene. The resulting sensor is formed by a single catadioptric camera and an omnidirectional light projector. It is also discussed how this sensor can be used in robot navigation applications

WMR navigation using local potential field corridors and narrow local occupancy grid perception

Path planning and control strategies applied to autonomous mobile robots should fulfil safety rules as well as achieve final goals. Trajectory planning applications should be fast and flexible to allow real time implementations as well as environment interactions. The methodology presented uses the on robot information as the meaningful data necessary to plan a narrow passage by using a corridor based on attraction potential fields that approaches the mobile robot to the final desired configuration. It employs local and dense occupancy grid perception to avoid collisions. The key goals of this research project are computational simplicity as well as the possibility of integrating this method with other methods reported by the research community. Another important aspect of this work consist in testing the proposed method by using a mobile robot with a perception system composed of a monocular camera and odometers placed on the two wheels of the differential driven motion system. Hence, visual data are used as a local horizon of perception in which trajectories without collisions are computed by satisfying final goal approaches and safety criteria

Use of active personal dosemeters in interventional radiology and cardiology: Tests in hospitals - ORAMED project

Although active personal dosemeters (APDs) are not used quite often in hospital environments, the possibility to assess the dose and/or dose rate in real time is particularly interesting in interventional radiology and cardiology (IR/IC) since operators can receive relatively high doses while standing close to the primary radiation field.A study concerning the optimization of the use of APDs in IR/IC was performed in the framework of the ORAMED project, a Collaborative Project (2008-2011) supported by the European Commission within its 7th Framework Program. This paper reports on tests performed with APDs on phantoms using an X-ray facility in a hospital environment and APDs worn by interventionalists during routine practice in different European hospitals.The behaviour of the APDs is more satisfactory in hospitals than in laboratories with respect to the influence of the tube peak high voltage and pulse width, because the APDs are tested in scattered fields with dose equivalent rates generally lower than 1 Sv.h(-1).

La construcció del coneixement pràctic. Una anàlisi integrada des dels plans social i individual

La tesi doctoral aborda la relació entre coneixement i pràctica en l’àmbit de la pràctica professional dels mestres. Aquest problema s’aborda des de la psicologia històrico-cultural, la qual implica un trencament amb la “racionalitat tècnica” des de la que s’ha abordat el problema tradicionalment. Aquest nou abordatge de la problemàtica implica una considerable elaboració teòrica, que en la tesi es vehicula mitjançant dos constructes fonamentals: la situació i els conceptes pràctics. Les dades de la tesi consisteixen en les converses face-to-face i on-line entre un estudiant de Mestre en pràcticum i el seu tutor en el centre de pràctiques. L’estudi analitza dos casos d’uns quatre mesos de duració cadascun. L’anàlisi es porta a terme mitjançant anàlisi de discurs, utilitzant diverses unitats d’anàlisi i diverses dimensions, les quals fan possible una anàlisi integrada que permeti considerar de manera relacionada l’activitat conjunta (pla social) i l’ús individual de conceptes (pla individual). Els resultats preliminars suggereixen una especificitat estructural i genètica dels conceptes pràctics (en contrast amb els espontanis i científics), i l’existència de mecanismes d’activitat conjunta que potencien especialment el desenvolupament d’aquests conceptes.

Practical management of sunitinib toxicities in the treatment of pancreatic neuroendocrine tumors.

Pancreatic neuroendocrine tumors (pNETs) are infrequent malignancies which manifest in both functional (hormone-secreting) and more commonly non-functional (non-secreting) forms. The oral multitargeted tyrosine kinase inhibitor sunitinib and mammalian target of rapamycin (mTOR) inhibitor everolimus are approved as targeted therapies for patients with well-differentiated, non-resectable disease and evidence of disease progression. The recent approval of sunitinib for the management of advanced pNET is based on a continuous daily dosing (CDD) schedule that differs from the intermittent 4weeks on/2weeks off (4/2) schedule approved for sunitinib in advanced renal cell carcinoma (RCC) and imatinib-resistant gastrointestinal stromal tumor (GIST). Therefore, although clinicians may be familiar with therapy management approaches for sunitinib in advanced RCC and GIST, there is less available experience for the management of patients with a CDD schedule. Here, we discuss the similarities and differences in the treatment of pNET with sunitinib compared with advanced RCC and GIST. In particular, we focus on the occurrence and management of sunitinib-related toxicity in patients with pNET by drawing on experience in these other malignancies. We aim to provide a relevant and useful guide for clinicians treating patients with pNET covering the management of events such as fatigue, mucositis, hand-foot syndrome, and hypertension.

A guide to making an advance health care directive

This guide helps people residing in Andalucía to fill in their Advance Health Care Directives, also known as a Living Will. This document allows you to make known in advance and in writing your wishes and preferences about the health care that you wish to receive when you are unable to communicate because of illness. This guide gives simple and rapid information about how to fill in the document and how to express your wishes. It also contains additional information on Advance Health Care Directives and information onthe Andalusian Registry of Advance Health Care Directives.

Epigenetic mechanisms in non-alcoholic fatty liver disease: An emerging field.

Non-alcoholic fatty liver disease (NAFLD) is an emerging health concern in both developed and non-developed world, encompassing from simple steatosis to non-alcoholic steatohepatitis (NASH), cirrhosis and liver cancer. Incidence and prevalence of this disease are increasing due to the socioeconomic transition and change to harmful diet. Currently, gold standard method in NAFLD diagnosis is liver biopsy, despite complications and lack of accuracy due to sampling error. Further, pathogenesis of NAFLD is not fully understood, but is well-known that obesity, diabetes and metabolic derangements played a major role in disease development and progression. Besides, gut microbioma and host genetic and epigenetic background could explain considerable interindividual variability. Knowledge that epigenetics, heritable events not caused by changes in DNA sequence, contribute to development of diseases has been a revolution in the last few years. Recently, evidences are accumulating revealing the important role of epigenetics in NAFLD pathogenesis and in NASH genesis. Histone modifications, changes in DNA methylation and aberrant profiles or microRNAs could boost development of NAFLD and transition into clinical relevant status. PNPLA3 genotype GG has been associated with a more progressive disease and epigenetics could modulate this effect. The impact of epigenetic on NAFLD progression could deserve further applications on therapeutic targets together with future non-invasive methods useful for the diagnosis and staging of NAFLD.

Assessment of statistical iterative reconstructions to optimize CT examination protocols for children and young adults

La tomodensitométrie (CT) est une technique d'imagerie dont l'intérêt n'a cessé de croître depuis son apparition dans le début des années 70. Dans le domaine médical, son utilisation est incontournable à tel point que ce système d'imagerie pourrait être amené à devenir victime de son succès si son impact au niveau de l'exposition de la population ne fait pas l'objet d'une attention particulière. Bien évidemment, l'augmentation du nombre d'examens CT a permis d'améliorer la prise en charge des patients ou a rendu certaines procédures moins invasives. Toutefois, pour assurer que le compromis risque - bénéfice soit toujours en faveur du patient, il est nécessaire d'éviter de délivrer des doses non utiles au diagnostic.¦Si cette action est importante chez l'adulte elle doit être une priorité lorsque les examens se font chez l'enfant, en particulier lorsque l'on suit des pathologies qui nécessitent plusieurs examens CT au cours de la vie du patient. En effet, les enfants et jeunes adultes sont plus radiosensibles. De plus, leur espérance de vie étant supérieure à celle de l'adulte, ils présentent un risque accru de développer un cancer radio-induit dont la phase de latence peut être supérieure à vingt ans. Partant du principe que chaque examen radiologique est justifié, il devient dès lors nécessaire d'optimiser les protocoles d'acquisitions pour s'assurer que le patient ne soit pas irradié inutilement. L'avancée technologique au niveau du CT est très rapide et depuis 2009, de nouvelles techniques de reconstructions d'images, dites itératives, ont été introduites afin de réduire la dose et améliorer la qualité d'image.¦Le présent travail a pour objectif de déterminer le potentiel des reconstructions itératives statistiques pour réduire au minimum les doses délivrées lors d'examens CT chez l'enfant et le jeune adulte tout en conservant une qualité d'image permettant le diagnostic, ceci afin de proposer des protocoles optimisés.¦L'optimisation d'un protocole d'examen CT nécessite de pouvoir évaluer la dose délivrée et la qualité d'image utile au diagnostic. Alors que la dose est estimée au moyen d'indices CT (CTDIV0| et DLP), ce travail a la particularité d'utiliser deux approches radicalement différentes pour évaluer la qualité d'image. La première approche dite « physique », se base sur le calcul de métriques physiques (SD, MTF, NPS, etc.) mesurées dans des conditions bien définies, le plus souvent sur fantômes. Bien que cette démarche soit limitée car elle n'intègre pas la perception des radiologues, elle permet de caractériser de manière rapide et simple certaines propriétés d'une image. La seconde approche, dite « clinique », est basée sur l'évaluation de structures anatomiques (critères diagnostiques) présentes sur les images de patients. Des radiologues, impliqués dans l'étape d'évaluation, doivent qualifier la qualité des structures d'un point de vue diagnostique en utilisant une échelle de notation simple. Cette approche, lourde à mettre en place, a l'avantage d'être proche du travail du radiologue et peut être considérée comme méthode de référence.¦Parmi les principaux résultats de ce travail, il a été montré que les algorithmes itératifs statistiques étudiés en clinique (ASIR?, VEO?) ont un important potentiel pour réduire la dose au CT (jusqu'à-90%). Cependant, par leur fonctionnement, ils modifient l'apparence de l'image en entraînant un changement de texture qui pourrait affecter la qualité du diagnostic. En comparant les résultats fournis par les approches « clinique » et « physique », il a été montré que ce changement de texture se traduit par une modification du spectre fréquentiel du bruit dont l'analyse permet d'anticiper ou d'éviter une perte diagnostique. Ce travail montre également que l'intégration de ces nouvelles techniques de reconstruction en clinique ne peut se faire de manière simple sur la base de protocoles utilisant des reconstructions classiques. Les conclusions de ce travail ainsi que les outils développés pourront également guider de futures études dans le domaine de la qualité d'image, comme par exemple, l'analyse de textures ou la modélisation d'observateurs pour le CT.¦-¦Computed tomography (CT) is an imaging technique in which interest has been growing since it first began to be used in the early 1970s. In the clinical environment, this imaging system has emerged as the gold standard modality because of its high sensitivity in producing accurate diagnostic images. However, even if a direct benefit to patient healthcare is attributed to CT, the dramatic increase of the number of CT examinations performed has raised concerns about the potential negative effects of ionizing radiation on the population. To insure a benefit - risk that works in favor of a patient, it is important to balance image quality and dose in order to avoid unnecessary patient exposure.¦If this balance is important for adults, it should be an absolute priority for children undergoing CT examinations, especially for patients suffering from diseases requiring several follow-up examinations over the patient's lifetime. Indeed, children and young adults are more sensitive to ionizing radiation and have an extended life span in comparison to adults. For this population, the risk of developing cancer, whose latency period exceeds 20 years, is significantly higher than for adults. Assuming that each patient examination is justified, it then becomes a priority to optimize CT acquisition protocols in order to minimize the delivered dose to the patient. Over the past few years, CT advances have been developing at a rapid pace. Since 2009, new iterative image reconstruction techniques, called statistical iterative reconstructions, have been introduced in order to decrease patient exposure and improve image quality.¦The goal of the present work was to determine the potential of statistical iterative reconstructions to reduce dose as much as possible without compromising image quality and maintain diagnosis of children and young adult examinations.¦The optimization step requires the evaluation of the delivered dose and image quality useful to perform diagnosis. While the dose is estimated using CT indices (CTDIV0| and DLP), the particularity of this research was to use two radically different approaches to evaluate image quality. The first approach, called the "physical approach", computed physical metrics (SD, MTF, NPS, etc.) measured on phantoms in well-known conditions. Although this technique has some limitations because it does not take radiologist perspective into account, it enables the physical characterization of image properties in a simple and timely way. The second approach, called the "clinical approach", was based on the evaluation of anatomical structures (diagnostic criteria) present on patient images. Radiologists, involved in the assessment step, were asked to score image quality of structures for diagnostic purposes using a simple rating scale. This approach is relatively complicated to implement and also time-consuming. Nevertheless, it has the advantage of being very close to the practice of radiologists and is considered as a reference method.¦Primarily, this work revealed that the statistical iterative reconstructions studied in clinic (ASIR? and VECO have a strong potential to reduce CT dose (up to -90%). However, by their mechanisms, they lead to a modification of the image appearance with a change in image texture which may then effect the quality of the diagnosis. By comparing the results of the "clinical" and "physical" approach, it was showed that a change in texture is related to a modification of the noise spectrum bandwidth. The NPS analysis makes possible to anticipate or avoid a decrease in image quality. This project demonstrated that integrating these new statistical iterative reconstruction techniques can be complex and cannot be made on the basis of protocols using conventional reconstructions. The conclusions of this work and the image quality tools developed will be able to guide future studies in the field of image quality as texture analysis or model observers dedicated to CT.

Le mouvement peut-il guérir? : histoire de l'engagement des médecins français dans l'élaboration de l'éducation physique (1741-1888)

Résumé : Cette recherche doctorale analyse l'engagement des médecins français autour de l'éducation physique entre 1741 et 1888. Basé sur un travail prosopographique d'identification des médecins qui ont participé à l'élaboration de l'éducation physique, ce travail repose sur une mise en dialogue de leurs prises de position respectives. Pour réaliser cette enquête, nous avons compulsé un large corpus de sources primaires, composé des ouvrages consacrés à la gymnastique médicale mais aussi une très large portion de la production d'imprimés touchant à l'anatomie, l'hygiène, la thérapeutique, la physiologie, l'orthopédie, etc. Le corpus contient également des articles des principaux dictionnaires médicaux de la période et des principales revues médicales du XIXe siècle. Avec une approche critique de l'historiographie et à partir de ce corpus, nous avons travaillé dans le cadre de contextes définis pour saisir au plus près les logiques sociales et scientifiques amenant les médecins auprès de l'éducation physique. Trois conjonctures successives structurent l'engagement médical. Entre 1741 et 1817, la thèse retrace l'émergence d'un questionnement ; les années 1817-1847 constituent un « moment orthopédique » dans la formulation de la gymnastique ; et finalement entre 1847 et 1888, on observe une diversification des voies de légitimation médicale des exercices du corps. Ces trois moments de l'histoire des « discours gymniques médicaux » proposent un certain nombre de convergences : la prégnance de l'orthopédie, une certaine concentration autour de la santé des corps féminins, l'inclusion dans un « projet hygiéniste » ; mais aussi des divergences et des singularités : relatives à la progressive structuration en cours du champ médical, à l'implication progressive du politique (surtout après 1845/1850), aux transformations des pathologies/doctrines médicales « dominantes », ainsi qu'à l'importance plus ou moins forte de l'une ou l'autre des facettes de l'éducation physique (militaire, athlétique, « médicinale » ou pédagogique). Le processus est aussi celui de l'expérimentation de la curation de certaines pathologies (scolioses, affections nerveuses), dans des configurations idéologiques/scientifiques marquées par la « dégénération » (XVIIIe siècle), l'anatomie pathologique (début du XIXe siècle) et plus tard la « dégénérescence » et les affections nerveuses (après 1850). Dans le cadre d'une dynamique d'inspiration « foucaldienne », ces recommandations évoluent d'une anatomopolitique - caractérisée par un essor de discours empreints d'anatomie au XVIIIe siècle - vers une biopolitique - caractérisée par l'engagement de l'Etat qui fait de la gymnastique une discipline d'enseignement, pensée à des fins hygiéniques dans la seconde moitié du XIXe - où le processus réside en fait dans une biologisation progressive des recommandations pratiques. Observée à l'aune de la formulation médicale de l'éducation physique, la biopolitique n'est pas réalisée dans la seconde moitié du XVIIIe, elle se compose lentement aux marges de l'institution scolaire et des gymnastiques pédagogico-militaires pour constituer un projet thérapeutique et hygiénique plus construit après 1850. Abstract : This dissertation analyzes French doctor's involvement in debates and initiatives concerning physical education between 1741 and 1888. Based on a prosopographic inventory of those physicians who participated in the development of physical education, it explores the variety of their discourses with respect to the practice of physical exercises. This investigation relies on a large selection of primary sources: works devoted to medical gymnastic, but also medical treatises related to anatomy, hygiene, therapeutics, physiology, orthopedics, etc. The sources also include articles from the major medical dictionaries and journals of the nineteenth century. These documents are used to explore the socio-scientific mechanisms that underlay physicians' commitment to physical education. Three chronological periods structure medical engagement in the area of physical education. Between 1741 and 1817 the thesis traces the emergence of a questioning; the years 1817 to 1847 represent an « orthopedic moment » in the development of gymnastics; finally between 1847 and 1888, one witnesses a diversification of the legitimation process between medicine and gymnastics. These three moments in the history of « medical and gymnastic discourses » offer a number of similarities: the weight of orthopedics, the ongoing focus on the health of the female body, and the association of these discourses with a « hygienic project ». But differences also distinguish these periods as the medical field became more structured and new medical doctrines became dominant, with the increasing involvement of politics (especially after 1850), and with the changing weight of priorities within physical education (military, athletic, « medical » or pedagogic). Medical discourses centered on the curing of certain diseases (scoliosis or nervous disorders) are analyzed within an ideological configuration marked by the idea of « degeneration » (in the eighteenth century), « pathological anatomy » (in the early nineteenth century) and later « dégénérescence » associated with nervous disorders (after 1850). The dissertation draws on Foucault's historical epistemology to understand how medical recommendations evolve from an anatomopolitics - characterized by a surge in anatomical discourses - toward a biopolitics - characterized by the commitment of the State to introduce gymnastics for hygienic purposes into schools in the second half of the nineteenth century. This process reveals a progressive "biologization" of practical recommendations. The medical discourses about physical education show that Foucault's biopolitical power is not achieved in the second half of the eighteenth century, but develops slowly at the margins of the school system and of pedagogical and military gymnastic, becoming a veritable hygienic and therapeutic project only after 1850.

Homemade thermometry instruments in the field.

OBJECTIVE: Esophageal temperature is the gold standard for in-the-field temperature monitoring in hypothermic victims with cardiac arrest. For practical reasons, some mountain rescue teams use homemade esophageal thermometers to measure esophageal temperature; these consist of nonmedical inside/outside temperature monitoring instruments that have been modified to allow for esophageal insertion. We planned a study to determine the accuracy of such thermometers. METHODS: Two of the same model of digital cabled indoor/outdoor thermometer were modified and tested in comparison with a reference thermometer. The thermometers were tested in a water bath at different temperatures between 10°C and 35.2°C. Three hundred measurements were taken with each thermometer. RESULTS: Our experimental study showed that both homemade thermometers provided a good correlation and a clinically acceptable agreement in comparison with the reference thermometer. Measurements were within 0.5°C in comparison with the reference thermometer 97.5% of the time. CONCLUSIONS: The homemade thermometers performed well in vitro, in comparison with a reference thermometer. However, because these devices in their original form are not designed for clinical use, their use should be restricted to situations when the use of a conventional esophageal thermometer is impossible.

From MuSIASEM theory to practice: report and reflections from field research in Kampot province, Cambodia

This document contains a report and summary of the field research activities in a rural community of rice farmers in Kampot province, Cambodia in 2011, which I conducted within the context of my PhD research at ICTA-UAB (Institute of Environmental Science and Technology, Autonomous University of Barcelona, Spain). The purpose of the field research was to gather data for a MuSIASEM analysis (Multi-Scale Integrated Analysis of Societal and Ecosystem Metabolism) at the village and household level, in order to analyze the multidimensional challenges that small farmers may face nowadays within the context of global rural change and declining access to land. While the literature on MuSIASEM offers a great variety of theoretical explanations and practical applications, there is little information available for students regarding the practical steps required for doing a MuSIASEM analysis at the local level. Within this context, this report offers not only a documentation of the field research design and data collection methods, but further provides a general overview on some organizational and preparative aspects, including some personal reflections, that one may face when preparing and conducting field research for MuSIASEM analysis. In summary, this document thus serves three objectives: (i) to assure methodological transparency for the future work, based on the collected data during field research, (ii) to share my personal experience on the preparative and practical steps required for field research and data collection for a MuSIASEM analysis at the local level, and (iii) to make available for the further interested reader some more detailed background information on the case study village.

Sequencing and characterizing the genome of Estrella lausannensis as an undergraduate project: training students and biological insights.

With the widespread availability of high-throughput sequencing technologies, sequencing projects have become pervasive in the molecular life sciences. The huge bulk of data generated daily must be analyzed further by biologists with skills in bioinformatics and by "embedded bioinformaticians," i.e., bioinformaticians integrated in wet lab research groups. Thus, students interested in molecular life sciences must be trained in the main steps of genomics: sequencing, assembly, annotation and analysis. To reach that goal, a practical course has been set up for master students at the University of Lausanne: the "Sequence a genome" class. At the beginning of the academic year, a few bacterial species whose genome is unknown are provided to the students, who sequence and assemble the genome(s) and perform manual annotation. Here, we report the progress of the first class from September 2010 to June 2011 and the results obtained by seven master students who specifically assembled and annotated the genome of Estrella lausannensis, an obligate intracellular bacterium related to Chlamydia. The draft genome of Estrella is composed of 29 scaffolds encompassing 2,819,825 bp that encode for 2233 putative proteins. Estrella also possesses a 9136 bp plasmid that encodes for 14 genes, among which we found an integrase and a toxin/antitoxin module. Like all other members of the Chlamydiales order, Estrella possesses a highly conserved type III secretion system, considered as a key virulence factor. The annotation of the Estrella genome also allowed the characterization of the metabolic abilities of this strictly intracellular bacterium. Altogether, the students provided the scientific community with the Estrella genome sequence and a preliminary understanding of the biology of this recently-discovered bacterial genus, while learning to use cutting-edge technologies for sequencing and to perform bioinformatics analyses.

Practical considerations for conducting ecotoxicity test methods with manufactured nanomaterials: what have we learnt so far?

This review paper reports the consensus of a technical workshop hosted by the European network, NanoImpactNet (NIN). The workshop aimed to review the collective experience of working at the bench with manufactured nanomaterials (MNMs), and to recommend modifications to existing experimental methods and OECD protocols. Current procedures for cleaning glassware are appropriate for most MNMs, although interference with electrodes may occur. Maintaining exposure is more difficult with MNMs compared to conventional chemicals. A metal salt control is recommended for experiments with metallic MNMs that may release free metal ions. Dispersing agents should be avoided, but if they must be used, then natural or synthetic dispersing agents are possible, and dispersion controls essential. Time constraints and technology gaps indicate that full characterisation of test media during ecotoxicity tests is currently not practical. Details of electron microscopy, dark-field microscopy, a range of spectroscopic methods (EDX, XRD, XANES, EXAFS), light scattering techniques (DLS, SLS) and chromatography are discussed. The development of user-friendly software to predict particle behaviour in test media according to DLVO theory is in progress, and simple optical methods are available to estimate the settling behaviour of suspensions during experiments. However, for soil matrices such simple approaches may not be applicable. Alternatively, a Critical Body Residue approach may be taken in which body concentrations in organisms are related to effects, and toxicity thresholds derived. For microbial assays, the cell wall is a formidable barrier to MNMs and end points that rely on the test substance penetrating the cell may be insensitive. Instead assays based on the cell envelope should be developed for MNMs. In algal growth tests, the abiotic factors that promote particle aggregation in the media (e.g. ionic strength) are also important in providing nutrients, and manipulation of the media to control the dispersion may also inhibit growth. Controls to quantify shading effects, and precise details of lighting regimes, shaking or mixing should be reported in algal tests. Photosynthesis may be more sensitive than traditional growth end points for algae and plants. Tests with invertebrates should consider non-chemical toxicity from particle adherence to the organisms. The use of semi-static exposure methods with fish can reduce the logistical issues of waste water disposal and facilitate aspects of animal husbandry relevant to MMNs. There are concerns that the existing bioaccumulation tests are conceptually flawed for MNMs and that new test(s) are required. In vitro testing strategies, as exemplified by genotoxicity assays, can be modified for MNMs, but the risk of false negatives in some assays is highlighted. In conclusion, most protocols will require some modifications and recommendations are made to aid the researcher at the bench. [Authors]

Determination and Evaluation of Alternative Methods for Managing and Controlling Highway-Related Dust Phase II—Demonstration Project, June 2005

The State of Iowa currently has approximately 69,000 miles of unpaved secondary roads. Due to the low traffic count on these unpaved o nts as ng e two dust ed d roads, paving with asphalt or Portland cement concrete is not economical. Therefore to reduce dust production, the use of dust suppressants has been utilized for decades. This study was conducted to evaluate the effectiveness of several widely used dust suppressants through quantitative field testing on two of Iowa’s most widely used secondary road surface treatments: crushed limestone rock and alluvial sand/gravel. These commercially available dust suppressants included: lignin sulfonate, calcium chloride, and soybean oil soapstock. These suppressants were applied to 1000 ft test sections on four unpaved roads in Story County, Iowa. Tduplicate field conditions, the suppressants were applied as a surface spray once in early June and again in late August or early September. The four unpaved roads included two with crushed limestone rock and two with alluvial sand/gravel surface treatmewell as high and low traffic counts. The effectiveness of the dust suppressants was evaluated by comparing the dust produced on treated and untreated test sections. Dust collection was scheduled for 1, 2, 4, 6, and 8 weeks after each application, for a total testiperiod of 16 weeks. Results of a cost analysis between annual dust suppressant application and biennial aggregate replacement indicated that the cost of the dust suppressant, its transportation, and application were relatively high when compared to that of thaggregate types. Therefore, the biennial aggregate replacement is considered more economical than annual dust suppressant application, although the application of annual dust suppressant reduced the cost of road maintenance by 75 %. Results of thecollection indicated that the lignin sulfonate suppressant outperformed calcium chloride and soybean oil soapstock on all four unpavroads, the effect of the suppressants on the alluvial sand/gravel surface treatment was less than that on the crushed limestone rock, the residual effects of all the products seem reasonably well after blading, and the combination of alluvial sand/gravel surface treatment anhigh traffic count caused dust reduction to decrease dramatically.

Defining the Attributes of Good In-Service Portland Cement Concrete Pavements, December 2004

Much of the current research in portland cement concrete (PCC) pavements deals with the analysis of early pavement life failures and seeks to find ways to prevent those from reoccurring. The Long Term Pavement Performance (LTPP) portion of the Strategic Highway Research Program (SHRP) has identified some of the key factors in designing and building new PCC pavements. This statement will build on the Iowa Highway Research Board (IHRB) project TR-463, Field Performance Study of Past Iowa Pavement Research: A Look Back. In Iowa and across the nation, there are multiple pavements that were built more than 20 years ago that have been and are continuing to provide very good service to the public. They are found on both state and local routes and in both low and high traffic volume areas. There is a need to learn what went into those pavements, from the subgrade through the surface, that makes them perform so well. The purpose of this research project was to conduct a scoping study that could be used to evaluate the need for additional research to study the attributes of well-performing concrete pavements. The concept of zero-maintenance jointed plain concrete pavements” was iterated in this study for long-lasting, well-performing portland cement concrete pavement sections. The scope of the study was limited to a brief literature survey, pavement performance data collection from many counties, cities, and primary and interstate roads in Iowa, field visits to many selected pavement sites, and analysis of the collected data. No laboratory orfield testing was conducted for this phase of the project. A problem statement with a research plan was created that could be used to guide the second phase of the project.