Potato

Soil erosion is a serious agricultural problem. Most of the available literature on the subject concerns nonirrigated cropland where natural precipitation and snowmelt water produce the forces needed to erode soil and transport sediment. Most of the water providing those forces for erosion on irrigated land is that applied by humans to supply water to growing crops. The purpose of this chapter is to provide a review of irrigation-induced soil erosion and to supply some insight into its hazards and control

Komfort auf Reise: Bedeutsamkeit von Schall und Vibration für einen komfortablen Flug

Die vorliegende Arbeit beschäftigt sich mit der Kombinationswirkung von Schall und Vibration (Vibro-Akustik) auf das Komforterleben in Flugzeugen. In Studie 1 wurden sieben Cruisingsituationen in einem Flugzeug-Mock-up präsentiert und von 117 Versuchspersonen mit Hilfe von 15 Polaritäten eines semantischen Differentials eingestuft. Hauptkomponentenanalysen zeigten, daß die Reize auf den Wahrnehmungsdimensionen (vibro-akustischer) Komfort, Variation und Tonhaltigkeit beurteilt wurden, die gemeinsam etwa 60% der Urteilsvarianz erfaßten. Vibro-akustischer Komfort erschien als bipolare Dimension des semantischen Wahrnehmungsraumes in Form subjektiven Wohlbefindens unter optimalen Bedingungen. Die Beurteilungen auf den ersten beiden Wahrnehmungsdimensionen korrelierten signifikant mit akustischen, psychoakustischen und Vibrationsparametern. In der zweiten Studie wurden der Schall- und Vibrationspegel zweier Cruisingsituationen mit Hilfe eines sogenannten Vibrationpad systematisch variiert (3 x 3 Design) und jeweils anhand des gleichen Differentials von 30 Versuchspersonen eingestuft. Varianzanalysen belegten eine signifikant „additive" Interaktion zwischen den variierten physikalischen Parametern im Hinblick auf die vibro-akustische Komfortbeurteilung, wobei der Schallpegel zu etwa 70% und der Vibrationspegel zu etwa 30% die Komfortbewertung bestimmten

Effects of Nocturnal Aircraft Noise - Volume 4 : Psychological Effects

A sleep laboratory study with 128 subjects was run using questionnaires to investigate the psycho-logical effects of nocturnal aircraft noise on annoyance, subjective aircraft noise exposure (intensity and frequency), sleep sensation, mood, stress and recuperation. 112 subjects served as experimen-tal groups, and they were exposed to aircraft noise of various intensities and frequencies during nine nights. A validation of the laboratory results took place by means of a field study which was conducted with 64 residents living in the vicinity of the Konrad-Adenauer-Airport Cologne/Bonn. For the laboratory study, there is a significant influence of aircraft noise (i.e., significant main ef-fects of the aircraft noise parameters maximum noise level LAS,max, number of aircraft noise events (level frequency), energy equivalent noise level LAS,eq), but not on mood, stress and recuperation. Annoyance and subjective aircraft noise exposure increase significantly with rising LAS,max, level fre-quency and LAS,eq. Regarding the sleep sensation only the frequency and the LAS,eq are relevant. Ac-cording to the prediction of dose-response curves for noise annoyance, which were derived by means of random effects logistic regression, the percentage of aircraft noise annoyed persons in the laboratory rises with increasing LAS,max and frequency. In the field and laboratory, there is an in-crease of the number of noise annoyed persons with rising LAS,eq. In the laboratory, the percentage of annoyed persons decreases above 46.6 dB(A) due to the presentation of louder aircraft noise events with lower frequencies in the night. Thereby, the significance of the number of nocturnal flight movements for the noise annoyance is pointed out. This is confirmed by the predictions made by the field model applying the frequency as independent variable. For the laboratory, significant moderators of annoyance are the assessed “necessity” of air traffic, the gender and the aircraft noise pre-annoyance; for the field the adaptation to aircraft noise and the age are significant

Annoyance from nocturnal aircraft noise exposure: Laboratory and field-specific dose-response curves

Dose-response curves regarding the annoying impact of nocturnal aircraft noise were calculated for the (1) maximum noise level LAS,max combined with the number of aircraft noise events and for the (2) energy equivalent noise level LAS,eq event by means of random effects logistic regression. These parameters were compared according to their predictive properties for annoyance ratings. Questionnaire surveys with 128 subjects of a laboratory study performed at the DLR Institute of Aerospace Medicine served as data basis. The laboratory results were compared to the results of a field study carried out with 64 airport residents living in the vicinity of the Airport Cologne/Bonn. In the laboratory setting there was a significant rise of the portion of annoyed people depending on LAS,max and frequency of fly-overs. Unlike previous studies, the percent annoyed by aircraft noise also increased with LAS,max in nights with less than 16, but louder aircraft noise events. The group of annoyed subjects also significantly increased with the LAS,eq event; however, above 50 dBA it decreased again since fewer but louder events were presented in the underlying combinations of noise level (45 to 80 dBA LAS,max) and number of noise events per night (4 to 128). Data from the field study confirmed the trend of the laboratory dose-response relationships. Nevertheless, the curves established in the laboratory lay above the field-specific curves, i.e., subjects felt more annoyed by aircraft noise in the laboratory setting than in their domestic environment. This was most probably caused by the increased number of awakenings in the laboratory compared to field conditions. The findings of the studies indicate that not only the energy equivalent noise level, as used in noise abatement rules of many countries, but also the number of aircraft events are a major source of nocturnal aircraft noise induced annoyance