A forward speed effects study on jet noise from several suppressor nozzles in the NASA/Ames 40- by 80-foot wind tunnel

A test program was conducted in a 40 by 80 foot wind tunnel to evaluate the effect of relative velocity on the jet noise signature of a conical ejector, auxiliary inlet ejector, 32 spokes and 104 tube nozzle with and without an acoustically treated shroud. The freestream velocities in the wind tunnel were varied from 0 to 103.6 m/sec (300 ft/sec) for exhaust jet velocities of 259.1 m/sec (850 ft/sec) to 609.6 m/sec (2000 ft/sec). Reverberation corrections for the wind tunnel were developed and the procedure is explained. In conjunction with wind tunnel testing the nozzles were also evaluated on an outdoor test stand. The wind tunnel microphone arrays were duplicated during the outdoor testing. The data were then extrapolated for comparisons with data measured using a microphone array placed on a 30.5 meter (100 ft) arc. Using these data as a basis, farfield to nearfield arguments are presented with regards to the data measured in the wind tunnel. Finally, comparisons are presented between predictions made using existing methods and the measured data

Analisis Kesediaan Membayar Wtp (Willingness To Pay) dalam Upaya Pengelolaan Obyek Wisata Taman Alun Kapuas Pontianak, Kalimantan Barat

Berbagai fungsi yang terkait dengan sumber daya alam (fungsi ekologis, sosial, ekonomi, dan arsitektural) dannilai estetika yang dimilikinya (obyek dan lingkungan) dapat meningkatkan kualitas lingkungan dan untukkelangsungan kehidupan perkotaan juga dapat menjadi nilai kebanggaan dan identitas kota. Sebagai obyekwisata alam, Taman Alunalun Kapuas belum tertata dengan baik, pelaksanaan upaya pengelolaan objek wisataTaman Alun Kapuas membutuhkan biaya yang tidak sedikit. Untuk itu diharapkan bagi pengunjung untukmembayar dalam pengelolaan Taman Alun Kapuas. Penelitian ini menggunakan analisis regresi logistik dalammenganalisis faktor-faktor kesediaan pengunjung untuk membayar. Sedangkan metode CVM (ContingenValuation Method) digunakan untuk mengestimasi biaya yang akan dikeluarkan oleh pengunjung, dan metoderegresi berganda digunakan untuk menganalisis faktor-faktor apa yang mempengaruhi besar kesediaanmembayar pengunjung. Program yang dapat membantu dalam penelitian ini yaitu Microsoft Excel 2007 danMinitab For Windows Realise 16. Hasil penelitian menunjukkan bahwa sebanyak 84% responden bersediamembayar dalam upaya pengelolaan lingkungan obyek wisata Taman Alun Kapuas. Faktor-faktor yangmempengaruhi kesediaan membayar responden pengunjung dalam upaya pengelolaan lingkungan obyekwisata Taman Alun Kapuas antara lain pendapatan (PNDPTN3) dan pengetahuan (PNGTHUAN). Nilai rata-rataWTP responden pengunjung adalah sebesar Rp 3360,00/orang. Faktor yang mempengaruhi nilai WTPresponden yaitu usia (U)

Impacts of Climate Change on indirect human exposure to pathogens and chemicals from agriculture

Objective: Climate change is likely to affect the nature of pathogens and chemicals in the environment and their fate and transport. Future risks of pathogens and chemicals could therefore be very different from those of today. In this review, we assess the implications of climate change for changes in human exposures to pathogens and chemicals in agricultural systems in the United Kingdom and discuss the subsequent effects on health impacts. Data sources: In this review, we used expert input and considered literature on climate change ; health effects resulting from exposure to pathogens and chemicals arising from agriculture ; inputs of chemicals and pathogens to agricultural systems ; and human exposure pathways for pathogens and chemicals in agricultural systems. Data synthesis: We established the current evidence base for health effects of chemicals and pathogens in the agricultural environment ; determined the potential implications of climate change on chemical and pathogen inputs in agricultural systems ; and explored the effects of climate change on environmental transport and fate of different contaminant types. We combined these data to assess the implications of climate change in terms of indirect human exposure to pathogens and chemicals in agricultural systems. We then developed recommendations on future research and policy changes to manage any adverse increases in risks. Conclusions: Overall, climate change is likely to increase human exposures to agricultural contaminants. The magnitude of the increases will be highly dependent on the contaminant type. Risks from many pathogens and particulate and particle-associated contaminants could increase significantly. These increases in exposure can, however, be managed for the most part through targeted research and policy changes

The effects of pesticide mixtures on degradation of pendimethalin in soils

Most agronomic situations involve a sequence of herbicide, fungicide, and insecticide application. On the other hand, use of pesticidal combinations has become a standard practice in the production of many agricultural crops. One of the most important processes influencing the behavior of a pesticide in the environment is its degradation in soil. It is known that due to several pesticide applications in one vegetation season, the pesticide may be present in mixtures with other pesticides or xenobiotics in soil. This study examines the role which a mixture of chemicals plays in pesticide degradation. The influence of other pesticides on the rate of pendimethalin (PDM) degradation in soil was measured in controlled conditions. Mixtures of PDM with mancozeb or mancozeb and thiamethoxam significantly influenced the degradation of pendimethalin under controlled conditions. The second type of mixtures, with metribuzin or thiamethoxam, did not affect the behavior of pendimethalin in soil. Also, we determined the influence of water content on the rate of pendimethalin degradation alone in two soils and compared it to the rate in three pesticide mixtures. We compared two equations to evaluate the predictors of the rate of herbicide dissipation in soil: the first-order kinetic and the non-linear empirical models. We used the non-linear empirical model assuming that the degradation rate of a herbicide in soil is proportional to the difference of the observed concentration of herbicide in soil at time and concentration of herbicide in the last day of measurement