Development and Demonstration of a Freezing Drizzle Algorithm for Roadway Environmental Sensing Systems, Final Report, October 2012

The primary goal of this project is to demonstrate the accuracy and utility of a freezing drizzle algorithm that can be implemented on roadway environmental sensing systems (ESSs). The types of problems related to the occurrence of freezing precipitation range from simple traffic delays to major accidents that involve fatalities. Freezing drizzle can also lead to economic impacts in communities with lost work hours, vehicular damage, and downed power lines. There are means for transportation agencies to perform preventive and reactive treatments to roadways, but freezing drizzle can be difficult to forecast accurately or even detect as weather radar and surface observation networks poorly observe these conditions. The detection of freezing precipitation is problematic and requires special instrumentation and analysis. The Federal Aviation Administration (FAA) development of aircraft anti-icing and deicing technologies has led to the development of a freezing drizzle algorithm that utilizes air temperature data and a specialized sensor capable of detecting ice accretion. However, at present, roadway ESSs are not capable of reporting freezing drizzle. This study investigates the use of the methods developed for the FAA and the National Weather Service (NWS) within a roadway environment to detect the occurrence of freezing drizzle using a combination of icing detection equipment and available ESS sensors. The work performed in this study incorporated the algorithm developed initially and further modified for work with the FAA for aircraft icing. The freezing drizzle algorithm developed for the FAA was applied using data from standard roadway ESSs. The work performed in this study lays the foundation for addressing the central question of interest to winter maintenance professionals as to whether it is possible to use roadside freezing precipitation detection (e.g., icing detection) sensors to determine the occurrence of pavement icing during freezing precipitation events and the rates at which this occurs.

Inside IPERS and Pensioners’ Post, Winter 2004-2005

I am pleased to send you this special edition newsletter, which includes a fi nancial summary on pages 2 and 3. Providing you fi nancial and performance information refl ects my commitment to accountability. IPERS’ performance continues to be strong, as does the commitment of the Governor, Legislature, employers, members, the Investment Board, the Benefi ts Advisory Committee (BAC), and staff to maintaining a good retirement plan. Unfortunately, IPERS’ good performance and everyone’s commitment does not eliminate the need for a contribution rate increase. There are many reasons for this. We must make up for losses from the recent bear markets. Also, our retirees are living longer; therefore, they are drawing pensions longer.

Evaluating Roadway Subsurface Drainage Practices, 2013

The bearing capacity and service life of a pavement is affected adversely by the presence of undrained water in the pavement layers. In cold winter climates like in Iowa, this problem is magnified further by the risk of frost damage when water is present. Therefore, well-performing subsurface drainage systems form an important aspect of pavement design by the Iowa Department of Transportation (DOT). However, controversial findings are also reported in the literature regarding the benefits of subsurface drainage. The goal of this research was not to investigate whether subdrains are needed in Iowa pavements, but to conduct an extensive performance review of primary interstate pavement subdrains in Iowa, determine the cause of the problem if there are drains that are not functioning properly, and investigate the effect of poor subdrain performance due to improper design, construction, and maintenance on pavement surface distresses, if any. An extensive literature review was performed covering national-level and state-level research studies mainly focusing on the effects of subsurface drainage on performance of asphalt and concrete pavements. Several studies concerning the effects of a recycled portland cement concrete (RPCC) subbase on PCC pavement drainage systems were also reviewed. A detailed forensic test plan was developed in consultation with the project technical advisory committee (TAC) for inspecting and evaluating the Iowa pavement subdrains. Field investigations were conducted on 64 selected (jointed plain concrete pavement/JPCP and hot-mix asphalt/HMA) pavement sites during the fall season of 2012 and were mainly focused on the drainage outlet conditions. Statistical analysis was conducted on the compiled data from field investigations to further investigate the effect of drainage on pavement performance. Most Iowa subsurface drainage system outlet blockage is due to tufa, sediment, and soil. Although higher blockage rates reduce the flow rate of water inside outlet pipes, it does not always stop water flowing from inside the outlet pipe to outside the outlet pipe unless the outlet is completely blocked. Few pavement surface distresses were observed near blocked subsurface drainage outlet spots. More shoulder distresses (shoulder drop or cracking) were observed near blocked drainage outlet spots compared to open ones. Both field observations and limited performance analysis indicate that drainage outlet conditions do not have a significant effect on pavement performance. The use of RPCC subbase in PCC pavements results in tufa formation, a primary cause of drainage outlet blockage in JPCP. Several useful recommendations to potentially improve Iowa subdrain performance, which warrant detailed field investigations, were made

Evaluating Roadway Subsurface Drainage Practices: Tech Transfer Summary, 2013.

The bearing capacity and service life of a pavement is affected adversely by the presence of undrained water in the pavement layers. In cold winter climates like in Iowa, this problem is magnified further by the risk of frost damage when water is present. Therefore, well-performing subsurface drainage systems form an important aspect of pavement design by the Iowa Department of Transportation (DOT). However, controversial findings are also reported in the literature regarding the benefits of subsurface drainage. The goal of this research was not to investigate whether subdrains are needed in Iowa pavements, but to conduct an extensive performance review of primary interstate pavement subdrains in Iowa, determine the cause of the problem if there are drains that are not functioning properly, and investigate the effect of poor subdrain performance due to improper design, construction, and maintenance on pavement surface distresses, if any. An extensive literature review was performed covering national-level and state-level research studies mainly focusing on the effects of subsurface drainage on performance of asphalt and concrete pavements. Several studies concerning the effects of a recycled portland cement concrete (RPCC) subbase on PCC pavement drainage systems were also reviewed. A detailed forensic test plan was developed in consultation with the project technical advisory committee (TAC) for inspecting and evaluating the Iowa pavement subdrains. Field investigations were conducted on 64 selected (jointed plain concrete pavement/JPCP and hot-mix asphalt/HMA) pavement sites during the fall season of 2012 and were mainly focused on the drainage outlet conditions. Statistical analysis was conducted on the compiled data from field investigations to further investigate the effect of drainage on pavement performance. Most Iowa subsurface drainage system outlet blockage is due to tufa, sediment, and soil. Although higher blockage rates reduce the flow rate of water inside outlet pipes, it does not always stop water flowing from inside the outlet pipe to outside the outlet pipe unless the outlet is completely blocked. Few pavement surface distresses were observed near blocked subsurface drainage outlet spots. More shoulder distresses (shoulder drop or cracking) were observed near blocked drainage outlet spots compared to open ones. Both field observations and limited performance analysis indicate that drainage outlet conditions do not have a significant effect on pavement performance. The use of RPCC subbase in PCC pavements results in tufa formation, a primary cause of drainage outlet blockage in JPCP. Several useful recommendations to potentially improve Iowa subdrain performance, which warrant detailed field investigations, were made.

Advances in Near-surface Seismology and Ground-penetrating Radar

Advances in Near-surface Seismology and Ground-penetrating Radar (SEG Geophysical Developments Series No. 15) is a collection of original papers by renowned and respected authors from around the world. Technologies used in the application of near-surface seismology and ground-penetrating radar have seen significant advances in the last several years. Both methods have benefited from new processing tools, increased computer speeds, and an expanded variety of applications. This book, divided into four sections ? ?Reviews,? ?Methodology,? ?Integrative Approaches,? and ?Case Studies? ? captures the most significant cutting-edge issues in active areas of research, unveiling truly pertinent studies that address fundamental applied problems. This collection of manuscripts grew from a core group of papers presented at a postconvention workshop, ?Advances in Near-surface Seismology and Ground-penetrating Radar,? held during the 2009 SEG Annual Meeting in Houston, Texas. This is the first cooperative publication effort between the near-surface communities of SEG, AGU, and EEGS. It will appeal to a large and diverse audience that includes researchers and practitioners inside and outside the near-surface geophysics community.

Multiple processes regulate long-term population dynamics of sea urchins on Mediterranean rocky reefs

We annually monitored the abundance and size structure of herbivorous sea urchin populations (Paracentrotus lividus and Arbacia lixula) inside and outside a marine reserve in the Northwestern Mediterranean on two distinct habitats (boulders and vertical walls) over a period of 20 years, with the aim of analyzing changes at different temporal scales in relation to biotic and abiotic drivers. P. lividus exhibited significant variability in density over time on boulder bottoms but not on vertical walls, and temporal trends were not significantly different between the protection levels. Differences in densities were caused primarily by variance in recruitment, which was less pronounced inside the MPA and was correlated with adult density, indicating density-dependent recruitment under high predation pressure, as well as some positive feedback mechanisms that may facilitate higher urchin abundances despite higher predator abundance. Populations within the reserve were less variable in abundance and did not exhibit the hyper-abundances observed outside the reserve, suggesting that predation effects maybe more subtle than simply lowering the numbers of urchins in reserves. A. lixula densities were an order of magnitude lower than P. lividus densities and varied within sites and over time on boulder bottoms but did not differ between protection levels. In December 2008, an exceptionally violent storm reduced sea urchin densities drastically (by 50% to 80%) on boulder substrates, resulting in the lowest values observed over the entire study period, which remained at that level for at least two years (up to the present). Our results also showed great variability in the biological and physical processes acting at different temporal scales. This study highlights the need for appropriate temporal scales for studies to fully understand ecosystem functioning, the concepts of which are fundamental to successful conservation and management.

Effects of total fishing prohibition on the rocky fish assemblages of Medes Islands marine reserve (NW Mediterranean)

Visual scuba diving censuses were used to assess the effects of fishing prohibition on abundance and size structure of littoral fish populations by comparing the same benthic communities inside and outside the protected area of Medes Islands (NE Catalonia, Spain). The total number of species found was 43 in the reserve and 44 outside, but the mean value of species richness per sampling station was significantly higher in the protected area. However, diversity, heavily affected by the presence or absence of large schools of pelagic species, showed no significant differences between sites. The prohibition of fishing for 6 years is the first factor affecting the qualitative and quantitative structure of fish populations ('reserve effect'), and depth is the second factor. Thus, except in the cases of Serranus cabrilla and Mullus surmuletus, all other vulnerable species are highly sensitive to the protection measures. The size structure of all vulnerable species was found to be absolutely different at the reserve sites than in the unprotected zones, and the modal size classes of size frequency distributions were always higher in the reserve than outside. The reserve effect was significantly responsible of the differences observed in this change on size structure. Some highly vulnerable species, such as Epinephelus guaza and Sciaena umbra, have only been found in the protected area. Others, such as Sparus aurata, Diplodus cervinus and Dicentrarchus labrax, were much more frequent inside the reserve.

Inside magazine, November 2013.

Iowa Department of Transportation Newsletter. INSIDE Magazine is developed to help keep all Iowa DOT employees informed about critical issues affecting them, recognize DOT employees for their excellent service and share interesting aspects in the lives of our co-workers.

Inside magazine, December 2013-January 2014

Iowa Department of Transportation Newsletter. INSIDE Magazine is developed to help keep all Iowa DOT employees informed about critical issues affecting them, recognize DOT employees for their excellent service and share interesting aspects in the lives of our co-workers.

Behavioural types and ecological effects in a natural population of the cooperative cichlid Neolamprologus pulcher

The ecological relevance of behavioural syndromes is little studied in cooperative breeding systems where it is assumed that the behavioural type might influence individual decisions on helping and dispersal (e.g. shy, nonaggressive and nonexplorative individuals remain philopatric and helpful, whereas bold, aggressive, explorative individuals compete for vacancies outside their group and disperse). We measured the behavioural type of 19 subordinates in the cooperatively breeding cichlid fish Neolamprologus pulcher in their natural environment by quantifying six behavioural traits up to four times ('trials') in three different contexts, by presenting them with a conspecific intruder, a predator or nothing inside a tube. We found only moderate within-context repeatability (intraclass correlation coefficients) of the focal individual's behaviour, except for attacking either the conspecific or the predator inside the tube. The focal individual's attack rate of the tube was also positively affected by its group size. Averaging traits per context removed the between-trial variation, and consequently the across-context repeatability was very high for all six traits, except for territory maintenance. Trait values depended significantly on the context, except for territory defence. Consequently, individuals could be classified into different behavioural types based on their reaction towards the tube, but surprisingly, and opposite to laboratory studies in this species, ranging propensity and territory maintenance were not included in this behavioural syndrome. We suggest that more studies are needed to compare standardized focal personality tests (e.g. exploration propensity) with actual behaviour observed in nature (e.g. ranging and dispersal).

Inside Magazine, April 2012

Iowa Department of Transportation Newsletter. INSIDE Magazine is developed to help keep all Iowa DOT employees informed about critical issues affecting them, recognize DOT employees for their excellent service and share interesting aspects in the lives of our co-workers.

Inside Magazine, Fall 2011

Iowa Department of Transportation Newsletter. INSIDE Magazine is developed to help keep all Iowa DOT employees informed about critical issues affecting them, recognize DOT employees for their excellent service and share interesting aspects in the lives of our co-workers.