The Search for Signatures Of Transient Mass Loss in Active Stars

The habitability of an exoplanet depends on many factors. One such factor is the impact of stellar eruptive events on nearby exoplanets. Currently this is poorly constrained due to heavy reliance on solar scaling relationships and a lack of experimental evidence. Potential impacts of Coronal Mass Ejections (CMEs), which are a large eruption of magnetic field and plasma from a star, are space weather and atmospheric stripping. A method for observing CMEs as they travel though the stellar atmosphere is the type II radio burst, and the new LOw Frequency ARray (LOFAR) provides a means for detection. We report on 15 hours of observation of YZ Canis Minoris (YZ CMi), a nearby M dwarf flare star, taken in LOFAR's beam-formed observation mode for the purposes of measuring transient frequency-dependent low frequency radio emission. The observations utilized Low-Band Antenna (10-90 MHz) or High-Band Antenna (110-190 MHz) for five three-hour observation periods. In this data set, there were no confirmed type II events in this frequency range. We explore the range of parameter space for type II bursts constrained by our observations Assuming the rate of shocks is a lower limit to the rate at which CMEs occur, no detections in a total of 15 hours of observation places a limit of $\nu_{type II} < 0.0667$ shocks/hr $\leq \nu_{CME}$ for YZ CMi due to the stochastic nature of the events and limits of observational sensitivity. We propose a methodology to interpret jointly observed flares and CMEs which will provide greater constraints to CMEs and test the applicability of solar scaling relations

SURREY (Reino Unido). Inglaterra. Condado. Mapas generales. 1793 (1789-1790). 1:64000

Escala gráfica de 5 millas [= 12,5 cm]. Recuadro geográfico de 1' en 1'Orografía por normalesLímites de los hundred de los condados diferenciados por coloresTabla de signos convencionales para indicar iglesias, casas, bosques, caminos, límites, etc.Título enmarcado en cartela decorada con motivos vegetale

Designing a Locally Manufacturable Wheelchair for Nepal

Persons with disabilities in developing countries often lack the basic equipment needed to assist them in their daily lives. International Nepal Fellowship (INF) is a Christian medical organization located in Nepal that provides medical care and assistance to people with disabilities and other conditions. Currently, INF imports expensive wheelchairs that undergo a prolonged border process before being received by INF. INF has reached out to the Collaboratory to design a wheelchair that can withstand the challenges of Nepal’s terrain and can be manufactured from local materials. The Nepal Wheelchair team accepted this challenge and set out to design a wheelchair that can fulfill the needs of INF. The team began by researching wheelchair models for inspiration and eventually settled on two preliminary designs. In January 2020, the team traveled to Pokhara, Nepal to gain feedback from the staff at INF and select a final design based on their comments. During this trip, the team acquired and brought back locally available materials and parts in order to be able to construct a prototype using materials which are actually available in Nepal. After returning, the team began performing Finite Element Analysis on the frame design and tested the steel from the trip to determine its physical properties. With prototyping progress stalled by recent events, the team is focusing on perfecting the design and preparing an instruction manual for INF.https://mosaic.messiah.edu/engr2020/1005/thumbnail.jp

Effect of Phosphorus and Strontium Additions on Formation Temperature and Nucleation Density of Primary Silicon in Al-19 Wt Pct Si Alloy and Their Effect on Eutectic Temperature

The influence of P and Sr additions on the formation temperature and nucleation density of primary silicon in Al-19 wt pct Si alloy has been determined, for small volumes of melt solidified at cooling rates _T of ~0.3 and 1 K/s. The proportion of ingot featuring primary silicon decreased progressively with increased Sr addition, which also markedly reduced the temperature for first formation of primary silicon and the number of primary silicon particles per unit volume �Nv: When combined with previously published results, the effects of amount of P addition and cooling rate on �Nv are in reasonable accord with �Nv� _T ¼ ðp=6fÞ1=2 109 [250 � 215 (wt pct P)0.17]�3, where �Nv is in mm�3, _T is in K/s, and f is volume fraction of primary silicon. Increased P addition reduces the eutectic temperature, while increased Sr appears to generate a minimum in eutectic temperature at about 100 ppmw Sr

Designing a Locally Manufacturable Wheelchair for Nepal

Persons with disabilities in developing countries often lack the basic equipment needed to assist them in their daily lives. International Nepal Fellowship (INF) is a Christian medical organization located in Nepal that provides medical care and assistance to people with disabilities and other conditions. Currently, INF imports expensive wheelchairs that undergo a prolonged border process before being received. INF has reached out to the Collaboratory to design a wheelchair that can withstand the challenges of Nepal’s terrain and can be manufactured from local materials. The Nepal Wheelchair team accepted this challenge and set out to design a wheelchair that can fulfill their needs. The team began by researching wheelchair models for inspiration and eventually settled on two preliminary designs. In January 2020, the team traveled to Pokhara, Nepal to gain feedback from the staff at INF and select a final design based on their comments. During this trip, the team acquired and brought back locally available materials and parts available in Nepal in order to construct a prototype. This year, prototyping has been completed for the following elements: the central frame, wheel lock, footrest, wheel mounting assemblies and armrest fixtures. As a result of knowledge gained during prototyping, some design changes to the wheelchair have been made. Moving forward, the team will test the overall prototype for durability and prepare a manufacturing manual for INF.https://mosaic.messiah.edu/engr2021/1010/thumbnail.jp

LANCASHIRE (Reino Unido) (Inglaterra). S. Canales (1791). 1:42800

Comprende desde Manchester hasta Willow HallEscala gráfica de 5 millas [= 18,9 cm]. Orientado con lis en rosa de ocho vientosOrografía por trazosEn el ángulo izquierdo, tabla con diversos datos sobre el canal. En el ángulo superior derecho, aparece un amplio recuadro en blanc

Testing the daytime oxidizing capacity of the troposphere: 1994 OH field campaign at the Izaña Observatory, Tenerife

A field campaign was carried out during May 1994 at the Izaña station, Tenerife. This campaign was part of the program Environment and Climate sponsored by the European Commission to study the influence of European emissions on the oxidizing capacity of a clean tropospheric environment. Daytime and also nighttime measurements were made, covering the OH as well as the NO3 chemistry. This paper presents the OH measurements taken with a multipass optical absorption spectrometer (MOAS) and discusses the daytime chemistry in a statistical and therefore more preliminary way. All relevant parameters influencing the OH concentration were monitored. From the data the two main contributions to the OH production can clearly be discerned and are given by the primary production following the ozone photolysis and the O(1D)-H2O reaction and by the catalytic reactions of NOx in the recycling process. The latter processes prove to contribute a dominant part to the OH concentration. The measurements of the nonmethane hydrocarbons (NMHC) especially of the biogenics, indicate a considerable influence of the NMHC on the absolute values of the OH concentration at Tenerife.This work has been financially supported by the European Commission (grant EV5V-CT93-0321), by the DFG, and by the Fonds der Chemischen Industrie, which is gratefully acknowledged