Radiation environment for rendezvous and docking with nuclear rockets

Radiation environment data for the NERVA engine are provided which may be utilized in estimating radiation exposures associated with various space maneuvers. Spatial distributions of neutron and gamma tissue kerma rates produced during full thrust operation of the engine are presented. Final rendezvous with an orbiting space station would be achieved subsequent to full thrust operation during a period of 10 or more hours duration in which impulse is delivered by the propellant used for removal of decay heat. Consequently, post operation radiation levels are of prime importance in estimating space station exposures. Maps of gamma kerma rates around the engine are provided for decay times of 4 and 24 hours after a representative firing. Typical decay curves illustrating the dependence of post operation kerma rates on decay time and operating history are included. Examples of the kerma distributions around the engine which result from integration over specific exposure periods are shown

A Basin Analysis of the Wabigoon Area of Lake Agassiz, a Quaternary Clay Basin in Northwerstern Ontario

Information from a wide range of sources is integrated in a basin analysis of the Wabigoon Basin, a Quaternary clay basin located on the Canadian Shield in northwestern Ontario. The basin sediments were deposited between 10.9 ka and 9.5 ka, along the margin of the Rainy Lobe of the Laurentide Ice Sheet, which formed the northern boundary of proglacial Lake Agassiz. The basin architecture is dominated by four major elements: end moraines, eskers, kames and a clay plain, all of which overlie irregular bedrock topography. End moraines, eskers and kames are composed mainly of a fining upward sequence of gravels and sands. The geometry of these sedimentary units, and their sedimentary structures indicates they were deposited mainly by high and low-density turbidity currents, on ice-marginal subaqueous outwash fans. Eskers contain a core of coarse gravel and sand deposited within subglacial meltwater conduits, overlain by subaqueous fan sediments deposited at the conduit mouth. Esker ridges were formed during conduit filling events and flanking deposits were formed when a conduit remained in use during ice-marginal retreat. Where conduits were shortlived, isolated subaqueous fans (kames) were formed. A depositional model is proposed which relates moraine formation to catastrophic releases of subglacial meltwater and sediment simultaneously along the entire margin of the Rainy Lobe. The clay plain forms a broad blanket of fine-grained, rhythmically-bedded sediment which obscures bedrock topography, and often buries esker and kame deposits. Seismic profiles and overburden drilling reveal deep (50-70 m) bedrock lows beneath the clay plain. These lows, oriented sub-parallel to the ice margin, acted as sediment traps, and were infilled by the deposits of underflows generated at the ice margin.Les renseignements tirés d'un grand nombre de sources sont intégrés en vue de l'analyse du bassin de Wabigoon, situé sur le Bouclier canadien. Les sédiments qui le composent ont été déposés entre 10,9 et 9,5 ka, le long de la marge du lobe Rainy de l'Inlandsis laurentidien, qui formait la limite nord du Lac Agassiz. Les quatre formes principales qu'on y trouve sont les moraines frontales, les eskers, les kames et une plaine argileuse; ces formes recouvrent le relief irrégulier du substratum. Les moraines frontales, les eskers et les kames sont surtout composés d'une séquence de graviers et de sables s'affinant vers le haut. La géométrie de ces unités sédimentaires et leur structure montrent qu'elles ont en grande partie été déposées sur des épandages fluvioglaciaires sous-aquatiques de marge glaciaire par des courants de turbidité de haute et de basse densité. Les eskers renferment un noyau de gravier et de sable grossier déposés à l'intérieur des chenaux de fonte sous-glaciaires, recouverts par les sédiments de cône sous-aquatique déposés à l'embouchure des chenaux. Les crêtes d'eskers ont été édifiées en même temps que s'effectuait le remplissage des chenaux et les dépôts latéraux ont été formés alors qu'un chenal demeurait actif pendant le retrait glaciaire. Là où l'activité a été de courte durée, des cônes sous-aquatiques isolés (kames) se sont formés. On propose ici un modèle de mise en place des sédiments qui lie la formation des moraines à des écoulements sous-glaciaires catastrophiques et simultanés d'eau de fonte et de sédiments tout le long de la marge du lobe Rainy. La plaine argileuse forme une couverture étendue de sédiments à grains fins, à stratification rythmique, qui cache le relief du substratum et enfouit souvent les eskers et les kames. Les profils sismiques et les forages dans les dépôts meubles révèlent des dépressions profondes (50-70 m) dans le substratum sous Ia plaine argileuse.Informationen aus einer Vielfalt von Quellen sind fur die Analyse des Wabigoon-Beckens vereinigt, ein Quaternàr-Lehm-Becken, das sich auf dem kanadischen Schild befindet. Die Beckensedimente wurden zwischen 10.9 ka und 9.5 ka abgela-gert, entlang dem Rand der Rainy-Lobe der laurentidischen Eisdecke, welche die nôrdli-che Grenzlinie des proglazialen Agassiz-Sees bildete. Die Becken-Architektur wird von vier Hauptelementen beherrscht: Endmoràne, Eskers, Kames und eine Lehmebene. Die drei ersteren bestehen vor allem aus einer nach oben hin feiner werdenden Sequenz von Kies und Sand. Die Géométrie dieser Sediment-Einheiten und ihre Sediment-Strukturen zeigen, daB sie haupt-àchlich durch Dichtigkeitsstrômungen mit hoher und niedriger Dichte abgelagert wurden auf Unterwasser-Eisrand-Schwemmfàchern. Die Eskers enthalten einen Kern von grobem Kies und Sand, der innerhalb subgla-zialer Schmelzwasserkanàle abgelagert wurde, ùberlagert von Unterwasser-Fàcher-sedimenten, die an der Mùndung der Kanàle abgelagert wurden. Die Esker-Rùcken wurden wàhrend der Fùllung der Kanàle gebildet und seitliche Ablagerungen wurden gebildet, wenn ein Kanal wàhrend des Rùckzugs des Eisrands aktiv blieb. Wo Kanàle kurzlebig waren, bildeten sich isolierte Unterwasser-Fàcher (Kames). Ein Ablagerungsmodell wird vorgeschlagen, das die Bildung der Morâne mit katastrophenartigem gleichzeiti-gem Freiwerden von subglazialem Schmelz-wasser und Sedimenten entlang des ganzen RandsderRainy-Lobeverbindet. DieLehmebene bildet eine breite Decke von feinkôrnigem, rhythmisch gelagertem Sediment, welches die Topographie des anstehenden Gesteins verdeckt und hâufig Esker- und Kame-Ablagerungen ùberlagert. Die seismischen Profile und Bohrungen in den lockeren Ablagerungen lassen tiefe Niederungen (50-70 m) unter der Lehmebene im anstehenden Gestein erkennen

Optimasi Proses Karbonisasi Tandan Kosong Sawit Menggunakan Response Surface Methodology

Empty fruit bunches (EFB) is a source of biomass which has not been utilized optimally yet. EFB can be used as source of solid fuel in the form of charcoal because of its high calorific value 18,200.75 kJ / kg. The calorific value can be increased by carbonization. Carbonization is a process to convert lignoselulose biomass into charcoal within temperature range 300 – 600 °C in a limited oxygen environment. The purpose of this research is to utilize EFB as a source of solid fuel, to study the effect of process condition such as temperature, holding time, and feed size towards the characteristics of resulted charcoal and to optimize carbonization process from the data obtained. Reactor used for EFB carbonization is a tube furnace at operating conditions of temperature (350, 400 and 450 °C), holding time (90, 120 and 150 minutes) and feed size (2, 4 and 6 cm). Responses were analyzed, namely the calorific value and volatile matter by using Response Surface Methodology (RSM). Optimum conditions obtained are temperature 450 °C, holding time 90 minutes and feed size 6 cm with calorific value 28,106 kJ/kg and volatile matter 13.47 %. The most influential process variable for calorific value is temperature. Meanwhile for volatile matter, every process variables give significant effect

The Association Between Race and Diagnostic Delay of Retinoblastoma in US Children

The Association Between Race and Diagnostic Delay of Retinoblastoma in US Children Alexander K. Black1, Amanda E. Kahn2, Roberto Warman3, Noël C. Barengo4 1 Florida International University Herbert Wertheim College of Medicine, [email protected], ORCID: 0000-0003-1688-5109 2 Florida International University Herbert Wertheim College of Medicine, [email protected], ORICD: 0000-0002-8045-4576 3 Florida International University Herbert Wertheim College of Medicine, [email protected]. 4 Florida International University Herbert Wertheim College of Medicine, [email protected], ORCID: 0000-0003-0660-3091 Objective: Explore associations between race and age at diagnosis of retinoblastoma in children in the United States between 1988-2018. Methods: An analytical non-concurrent cohort study was conducted using the Surveillance, Epidemiology, and End Results (SEER) database from 1988-2018. The cohort includes children ages 0-17 diagnosed with retinoblastoma. The exposure was race and the outcome was age at diagnosis. Primary diagnosis after two years old was considered diagnostic delay. Covariates include sex, rural-urban continuum, ethnicity, decade of diagnosis, and disease laterality. Unadjusted and adjusted logistic regression analysis were performed to calculate odds ratios (OR) and 95% confidence intervals (CI). Results: In total, 747 participants met inclusion criteria. By racial group, 70.15% of participants were white, 16.33% black, 10.98% Asian/Pacific Islander and 2.54% American Indian/Alaska native. By ethnicity, 84.34% were non-Hispanic. No statistically significant associations between racial or ethnic groups and age at diagnosis compared to the non-Hispanic white control group (black OR 0.92; 95% CI 0.58-1.54, Asian/Pacific Islander OR 1.15; 95% CI 0.50-19.95, American Indian/Alaska native OR 0.61; 95% CI 0.20-1.85, Hispanic OR 0.86; 95% CI 0.52 -1.41) were found. Females were significantly more likely to be diagnosed under age two compared to males (OR 0.62; 95% CI 0.44-0.88). Conclusion: While many variables affect development of retinoblastoma, this nationwide study of US children suggests that timely identification of retinoblastoma does not differ based on race or ethnicity. Keywords: retinoblastoma, race/ethnicity, epidemiolog

Public Review terhadap Peraturan Pemerintah Tentang Kawasan Hutan

Regulasi yang menjadi objek public review di sini adalah Peraturan Pemerintah nomor 60 tentang Perubahan Atas Peraturan Pemerintah nomor 10 tahun 2010 Tentang Tata Cara Perubahan Peruntukan dan Fungsi Kawasan Hutan serta Peraturan Pemerintah nomor 61 tahun 2012 tentang Perubahan Atas Peraturan Pemerintah nomor 24 tahun 2010 Tentang Penggunaan Kawasan Hutan. Regulasi soal Kawasan Hutan diuji karena dinilai berpotensi memberikan impunitas atas pelanggaran hukum dan memiliki kerancuan, terutama alasan bahwa untuk memberikan kepastian hukum kepada pelaku usaha. Alasan tersebut dianggap menguntungkan pengusaha dibidang kehutanan dan perkebunan sawit namun merugikan masyarakat dan kelestarian lingkungan. Pemerintah dinilai telah memberikan perlindungan dan pengampunan atas pelanggaran undang-undang dan pencurian kekayaan alam di negeri ini