We present a system which allows users to draw on arbitrary display surfaces. The system is implemented using consumer electronics; data is gathered with a webcam, and most video analysis is done on a desktop graphics card. Two variants of the core system are discussed. In the first, users draw on a computer monitor using a laser pointer. In the second, a light pen is used to draw on a display ...

We developed a rapid, inexpensive method for isolating and identifying Rhizobium leguminosarum by. phaseoli strains from bean root nodules. The method can be used for other small or medium-sized nodules such as those of clover, alfalfa and peas. With this method, one person can process 115 nodules/h. Using a simple apparatus made of plexiglass and machine bolts, we simultaneously crushed 24 sur...

Low frequency dielectric measurements on plexiglass (PMMA) show that cooling and heating the sample at constant rate give an hysteretic dependence on temperature of the dielectric constant ǫ. A temporary stop of cooling produces a downward relaxation of ǫ. Two main features are observed i) when cooling is resumed ǫ goes back to the values obtained without the cooling stop (i.e. the low temperat...

We are 21 years into the 21st century, and educational practices across North America were woefully unprepared to ‘flip switch’ online learning; at times no education occurred all, not or onsite. The COVID-19 pandemic disruptor storm peeled off layers of blindfolds time accrued in an instant. Issues included three areas. Area one—unpreparedness: digital illiteracy ...

The effect of V-notches or reentrant corners on fracture propagation has been analyzed for brittle materials, but not for quasibrittle materials such as concrete, marked by a large material characteristic length producing a strong size effect transitional between plasticity and linear elastic fracture mechanics. A simple size effect law for the nominal strength of quasibrittle structures with s...

Every surface that is immersed in seawater becomes rapidly covered with an unavoidable biofi lm. Such biofi lm formation, also known as fouling, is a complex multistage process and not yet thoroughly investigated. In this study, the succession of diatoms and bacteria was investigated during a one month exposure on an artifi cial substrate of plexiglass (polymer of methyl methacrylate) mounted a...

Abstract Backward erosion piping is driven by seepage forces acting on the soil grains at downstream end of path. A new device for laboratory testing backward progression was developed and tested. The consists a plexiglass prism which path has been predefined. equipped with an inflow consisting gravel separated from tested sand strainer. hydraulic gradient along pipe observed set piezometers pr...

Low-frequency noise pollution in substations has a significant impact on the physical and mental health of workers. Reduction low-frequency is an urgent problem to solve for researchers. In this paper, different structures Al 2 O 3 -polyurethane composites micro-perforated plate were constructed, effects cavity depth, perforated plate, foam position sound absorption properties comprehensively i...

background: a set of hardware stereotactic radiosurgery is designed and constructed. the scope of this article is to describe how we have designed and developed stereotactic collimation assembly for a 9 mv neptun 10 pc linac. materials and methods: one collimator holder and six collimators were made, with their radiation field diameter between 12.5 mm to 25 mm at isocenter level. beam data, suc...