COMPTEL neutron response at 17 MeV

The Compton imaging telescope (COMPTEL) instrument of the Gamma Ray Observatory was exposed to 17 MeV d,t neutrons prior to launch. These data were analyzed and compared with Monte Carlo calculations using the MCNP(LANL) code. Energy and angular resolutions are compared and absolute efficiencies are calculated at 0 and 30 degrees incident angle. The COMPTEL neutron responses at 17 MeV and higher energies are needed to understand solar flare neutron data

Nonlocal density functionals and the linear response of the homogeneous electron gas

The known and usable truly nonlocal functionals for exchange-correlation energy of the inhomogeneous electron gas are the ADA (average density approximation) and the WDA (weighted density approximation). ADA, by design, yields the correct linear response function of the uniform electron gas. WDA is constructed so that it is exact in the limit of one-electron systems. We derive an expression for the linear response of the uniform gas in the WDA, and calculate it for several flavors of WDA. We then compare the results with the Monte-Carlo data on the exchange-correlation local field correction, and identify the weak points of conventional WDA in the homogeneous limit. We suggest how the WDA can be modified to improve the response function. The resulting approximation is a good one in both opposite limits, and should be useful for practical nonlocal density functional calculations.Comment: 4 pages, two eps figures embedde

PENGUKURAN DAN PENILAIAN KUALITAS UDARA DALAM RUANG PADA HUNIAN RUMAH SUSUN : STUDI KASUS RUSUNAWA TINGKULU MANADO

Abstract: Measurement and Evaluation of Indoor Air Quality in Residential Low – Income Apartment : Case Study of Rusunawa Tingkulu Manado This research aims to determine the air quality in the residential space of Rusunawa Tingkulu. Indoor air quality is very vulnerable to exposure to pollution both from outside and inside the room. Poor air quality can be a contributing factor to the health and comfort of occupants of residential spaces. The focus of this research is to determine and identify air quality variables in residential spaces, namely on physical quality such as wind speed, air temperature, relative humidity, Pm2.5, Pm10, and chemical quality such as CO₂, HCHO, VOC, and O₂ levels. The method used in this research is field observation using measuring instruments as instruments for measuring variables that affect indoor air quality. Air quality data obtained from measurements are compared with standard data on ideal air requirements in the home space referring to the Regulation of the Minister of Health of the Republic of Indonesia. The data is then described in the form of graphs and tabulations, then explained descriptively. From the results of the measurements taken, it was found that the physical quality and chemical quality of CO₂ in residential spaces did not meet the required standards. Meanwhile, chemical quality variables such as HCHO, VOC, and O₂ levels have met the ideal air quality standards in residential spaces

Detecting Intra-Fraction Motion in Patients Undergoing Radiation Treatment Using a Low-Cost Wireless Accelerometer

The utility of a novel, high-precision, non-intrusive, wireless, accelerometer-based patient orientation monitoring system (APOMS) in determining orientation change in patients undergoing radiation treatment is reported here. Using this system a small wireless accelerometer sensor is placed on a patient’s skin, broadcasting its orientation to the receiving station connected to a PC in the control area. A threshold-based algorithm is developed to identify the exact amount of the patient’s head orientation change. Through real-time measurements, an audible alarm can alert the radiation therapist if the user-defined orientation threshold is violated. Our results indicate that, in spite of its low-cost and simplicity, the APOMS is highly sensitive and offers accurate measurements. Furthermore, the APOMS is patient friendly, vendor neutral, and requires minimal user training. The versatile architecture of the APOMS makes it potentially suitable for variety of applications, including study of correlation between external and internal markers during Image-Guided Radiation Therapy (IGRT), with no major changes in hardware setup or algorithm