Experimental investigation of relevant road surface descriptors for tire-road noise measurements on low-absorbing road surfaces

Aufgrund von geräuschsenkenden Maßnahmen der Automobilindustrie ist der Kontakt zwischen Reifen und Straße heute die wichtigste Geräuschquelle außerhalb des Fahrzeugs. Diese Tendenz wird sich mit der Verbreitung von Elektrofahrzeugen noch verstärken. Mit zunehmender Forderung von Bevölkerung und Politik nach einer Reduzierung des Verkehrslärms wird die Regelung für die Reifen- und Fahrzeugzulassung regelmäßig verschärft. Daher sind weitere Untersuchungen über den Einfluss der Eigenschaften der Fahrbahnoberfläche auf die Geräuschemission von Reifen und Fahrzeugen erforderlich. Ziel dieser Arbeit ist es, die relevanten Fahrbahneigenschaften zu identifizieren, um das Reifen-Fahrbahn-Geräusch von frei rollenden Reifen mit einem systematischen Ansatz zu mindern. Da die Verwendung offenporiger Asphalte bereits als effiziente Maßnahme zur Reduzierung des Reifenrollgeräusches bekannt ist, konzentriert sich diese Arbeit auf kompakte Straßenoberflächen mit geringer Schallabsorption. Zunächst werden die Mechanismen, die Reifen-Fahrbahngeräusche erzeugen, sowie die wichtigsten Forschungsergebnisse über den Einfluss der Reifen- und der Straßeneigenschaften auf die Reifen-Fahrbahngeräusche vorgestellt. Nachdem die notwendigen theoretischen Grundlagen zum Verständnis dieser Arbeit vermittelt wurden, werden die verschiedenen Methoden zur akustischen Analyse der Wechselwirkung zwischen Fahrbahnoberfläche und Reifen vorgestellt. Diese Methoden werden in zwei Gruppen unterteilt: die Mess- und die statistischen Methoden. Die Anwendung statistischer Methoden auf die Messung der Fahrbahnoberfläche und des Reifenfahrgeräusches bietet mehrere Vorteile. Erstens können multidimensionale Daten auf Skalare reduziert werden, so dass die Anzahl der als Eingabe verwendeten Parameter minimiert wird. Dann können die wichtigsten Straßenbelagsparameter identifiziert werden, um das Reifen-Fahrbahngeräusch und einige seiner Entstehungsmechanismen wie die Rillenresonanz zu reduzieren. Am Ende wird eine Analyse durchgeführt, um festzustellen, ob die Definition der Homologationsprüfstrecke nach der Norm ISO 10844 vollständig genug ist oder ob zusätzliche Parameter benötigt werden, um die Geräuschvarianz zwischen verschiedenen, der Norm entsprechenden Prüfstrecken zu erklären. Anhand aller gesammelten Informationen kann eine optimale Straßenbelagsgestaltung vorgenommen werden, um die Reifen-Fahrbahn-Geräusche bei Homologationstests, aber auch bei normalen Rollbedingungen auf öffentlichen Straßen zu reduzieren

Signature proteins that are distinctive of alpha proteobacteria

BACKGROUND: The alpha (α) proteobacteria, a very large and diverse group, are presently characterized solely on the basis of 16S rRNA trees, with no known molecular characteristic that is unique to this group. The genomes of three α-proteobacteria, Rickettsia prowazekii (RP), Caulobacter crescentus (CC) and Bartonella quintana (BQ), were analyzed in order to search for proteins that are unique to this group. RESULTS: Blast analyses of protein sequences from the above genomes have led to the identification of 61 proteins which are distinctive characteristics of α-proteobacteria and are generally not found in any other bacteria. These α-proteobacterial signature proteins are generally of hypothetical functions and they can be classified as follows: (i) Six proteins (CC2102, CC3292, CC3319, CC1887, CC1725 and CC1365) which are uniquely present in most sequenced α-proteobacterial genomes; (ii) Ten proteins (CC1211, CC1886, CC2245, CC3470, CC0520, CC0365, CC0366, CC1977, CC3010 and CC0100) which are present in all α-proteobacteria except the Rickettsiales; (iii) Five proteins (CC2345, CC3115, CC3401, CC3467 and CC1021) not found in the intracellular bacteria belonging to the order Rickettsiales and the Bartonellaceae family; (iv) Four proteins (CC1652, CC2247, CC3295 and CC1035) that are absent from various Rickettsiales as well as Rhodobacterales; (v) Three proteins (RP104, RP105 and RP106) that are unique to the order Rickettsiales and four proteins (RP766, RP192, RP030 and RP187) which are specific for the Rickettsiaceae family; (vi) Six proteins (BQ00140, BQ00720, BQ03880, BQ12030, BQ07670 and BQ11900) which are specific to the order Rhizobiales; (vii) Four proteins (BQ01660, BQ02450, BQ03770 and BQ13470) which are specific for the order Rhizobiales excluding the family Bradyrhizobiaceae; (viii) Nine proteins (BQ12190, BQ11460, BQ11450, BQ11430, BQ11380, BQ11160, BQ11120, BQ11100 and BQ11030 which are distinctive of the Bartonellaceae family;(ix) Six proteins (CC0189, CC0569, CC0331, CC0349, CC2323 and CC2637) which show sporadic distribution in α-proteobacteria, (x) Four proteins (CC2585, CC0226, CC2790 and RP382) in which lateral gene transfers are indicated to have occurred between α-proteobacteria and a limited number of other bacteria. CONCLUSION: The identified proteins provide novel means for defining and identifying the α-proteobacteria and many of its subgroups in clear molecular terms and in understanding the evolution of this group of species. These signature proteins, together with the large number of α-proteobacteria specific indels that have recently been identified , provide evidence that all species from this diverse group share many unifying and distinctive characteristics. Functional studies on these proteins should prove very helpful in the identification of such characteristics

Hydrobiological Assessment of the Zambezi River System: A Review

One of the important projects within the Environment Program is that entitled: Decision Support Systems for Managing Large International Rivers. Funded by the Ford Foundation, UNEP, and CNRS France, the project includes two case studies focused on the Danube and the Zambezi river basins. The author was assigned the task of reviewing the published literature on water management issues in the Zambezi river basin, and related ecological questions. This paper includes a large number of references and, more importantly, synthesizes the various studies and provides the scientific basis for investigating a very complex set of management issues. This review will be a basic reference for further water management studies in the Zambezi river basin

Understanding the contribution of groove resonance to tire-road noise on different surfaces under various operating conditions

Reducing tire-road noise is now becoming more and more important during the tire development process. Tread profile randomization is used to avoid tonal components and reduce groove resonance noise. To better understand the groove resonance contribution to tire-road noise, we performed acoustic measurements on a test bench with two serial tires. We filled the grooves with acoustic foam to highlight the groove resonance’s contribution. We then varied the road surface, the tire load and the driving speed. In the end, we used a multiple linear regression to quantify the interaction between the varying parameters and the groove resonance noise. We show that groove resonance contributes an average of 1.7 dBA to the tire rolling noise of passenger car tires. Groove resonance noise also increases with the driving speed. While the tread pattern and the tire load are responsible for the spectral content of the groove resonance noise, the orientation of the road surface’s texture mainly influences the noise level of the groove resonance. The tire manufacturers should carefully consider these findings when developing noise-optimized patterns. This is especially true for tire approval tests, which take place on tracks and usually have a relatively low texture level that is oriented negatively

An experimental study of the effect of the manipulation of the anxiety level through the use of sodium amytal on the learning of emotionally charged material

Thesis (Ed.D.)--Boston Universit

Deforestation for oil palm alters the fundamental balance of the soil N cycle

This abstract contains mathematical characters (see download

Enrichment of Phosphate on Ferrous Iron Phases during Bio-Reduction of Ferrihydrite *

The reduction of less stable ferric hydroxides and formation of ferrous phases is critical for the fate of phosphorus in anaerobic soils and sediments. The interaction between ferrous iron and phosphate was investigated experimentally during the reduction of synthetic ferrihydrite with natural organic materials as carbon source. Ferrihydrite was readily reduced by dissimilatory iron reducing bacteria (DIRB) with between 52 % and 73 % Fe(III) converted to Fe(II) after 31 days, higher than without DIRB. Formation of ferrous phases was linearly coupled to almost complete removal of both aqueous and exchangeable phosphate. Simple model calculations based on the incubation data suggested ferrous phases bound phosphate with a molar ratio of Fe(II):P between 1.14- 2.25 or a capacity of 246- 485 mg·P·g −1 Fe(II). XRD analysis indicated that the ratio of Fe(II): P was responsible for the precipitation of vivianite (Fe3(PO4)2·8H2O), a dominant Fe(II) phosphate mineral in incubation systems. When the ratio of Fe(II):P was more than 1.5, the precipitation of Fe(II) phosphate was soundly crystallized to vivianite. Thus, reduction of ferric iron provides a mechanism for the further removal of available phosphate via the production of ferrous phases, with anaerobic soils and sediments potentially exhibiting a higher capacity to bind phosphate than some aerobic systems

Approaches for assessing the impacts of the Rural Development Programmes in the context of multiple intervening factors

The Common Monitoring and Evaluation Framework (CMEF) provides a single framework for monitoring and evaluation of all EU Rural Development Programmes (RDP) in the current programming period (2007-2013). It provides continuity from previous periods and constitutes a significant simplification as regards assessment of results and impacts, while at the same time offering greater flexibility to Member States. The European Evaluation Network for Rural Development has published a Working Paper on Approaches for assessing the impacts of the Rural Development Programmes in the context of multiple intervening factors. The aim of the Working Paper is to inspire and to encourage programme evaluators, not to restrict or constrain them. From a methodological perspective, the three common socio-economic impact indicators of the CMEF (economic growth, employment creation, labour productivity) are more closely related than the four common environmental impact indicators (reversing biodiversity decline, maintenance of High Nature Value faming and forestry, improvement in water quality, contribution to combating climate change).assessment of impacts, Rural Development Programmes, policy evaluation, EU policy, Agricultural and Food Policy,

Coupling 3D groundwater modeling with CFC-based age dating to classify local groundwater circulation in an unconfined crystalline aquifer

International audienceNitrogen pollution of freshwater and estuarine environments is one of the most urgent environmental crises. Shallow aquifers with predominantly local flow circulation are particularly vulnerable to agricultural contaminants. Water transit time and flow path are key controls on catchment nitrogen retention and removal capacity, but the relative importance of hydrogeological and topographical factors in determining these parameters is still uncertain. We used groundwater dating and numerical modeling techniques to assess transit time and flow path in an unconfined aquifer in Brittany, France. The 35.5 km2 study catchment has a crystalline basement underneath a ∼60 m thick weathered and fractured layer, and is separated into a distinct upland and lowland area by an 80 m-high butte. We used groundwater discharge and groundwater ages derived from chlorofluorocarbon (CFC) concentration to calibrate a free-surface flow model simulating groundwater flow circulation. We found that groundwater flow was highly local (mean travel distance = 350 m), substantially smaller than the typical distance between neighboring streams (∼1 km), while CFC-based ages were quite old (mean = 40 years). Sensitivity analysis revealed that groundwater travel distances were not sensitive to geological parameters (i.e. arrangement of geological layers and permeability profile) within the constraints of the CFC age data. However, circulation was sensitive to topography in the lowland area where the water table was near the land surface, and to recharge rate in the upland area where water input modulated the free surface of the aquifer. We quantified these differences with a local groundwater ratio (rGW-LOCAL), defined as the mean groundwater travel distance divided by the mean of the reference surface distances (the distance water would have to travel across the surface of the digital elevation model). Lowland, rGW-LOCAL was near 1, indicating primarily topographical controls. Upland, rGW-LOCAL was 1.6, meaning the groundwater recharge area is almost twice as large as the topographically-defined catchment for any given point. The ratio rGW-LOCAL is sensitive to recharge conditions as well as topography and it could be used to compare controls on groundwater circulation within or between catchments

Riparian corridors: A new conceptual framework for assessingt nitrogen buffering across biomes

Anthropogenic activities have more than doubled the amount of reactive nitrogen circulating on Earth, creating excess nutrients across the terrestrial-aquatic gradient. These excess nutrients have caused worldwide eutrophication, fundamentally altering the functioning of freshwater and marine ecosystems. Riparian zones have been recognized to buffer diffuse nitrate pollution, reducing delivery to aquatic ecosystems, but nutrient removal is not their only function in river systems. In this paper, we propose a new conceptual framework to test the capacity of riparian corridors to retain, remove, and transfer nitrogen along the continuum from land to sea under different climatic conditions. Because longitudinal, lateral, and vertical connectivity in riparian corridors influences their functional role in landscapes, we highlight differences in these parameters across biomes. More specifically, we explore how the structure of riparian corridors shapes stream morphology (the river's spine), their multiple functions at the interface between the stream and its catchment (the skin), and their biogeochemical capacity to retain and remove nitrogen (the kidneys). We use the nitrogen cycle as an example because nitrogen pollution is one of the most pressing global environmental issues, influencing directly and indirectly virtually all ecosystems on Earth. As an initial test of the applicability of our interbiome approach, we present synthesis results of gross ammonification and net nitrification from diverse ecosystems