Visualizing nuclear radiation

               

              

Extraordinary decontamination efforts are underway in areas affected by the 2011 nuclear accidents in Japan. The creation of total radioactivity maps is essential for thorough cleanup, but the most common methods, according to Kyoto University's Toru Tanimori, do not 'see' enough ground-level radiation.

"The best methods we have currently are labor intensive, and to measure surface radiation accurately," he says, "complex analysis is needed."
In their latest work published in Scientific Reports, Tanimori and his group explain how gamma-ray imaging spectroscopy is more versatile and robust, resulting in a clearer image.
"We constructed an Electron Tracking Compton Camera (ETCC) to detect nuclear gamma rays quantitatively. Typically this is used to study radiation from space, but we have shown that it can also measure contamination, such as at Fukushima."
The imaging revealed what Tanimori calls "micro hot spots" around the Fukushima Daiichi Nuclear Power Plant, even in regions that had already been considered decontaminated. In fact, the cleaning in some regions appeared to be far less than what could be measured by other means.
Current methods for measuring gamma rays do not reliably pinpoint the source of the radiation. According to Tanimori, "radiation sources including distant galaxies can disrupt the measurements."
The key to creating a clear image is taking a color image including the direction and energy of all gamma rays emitted in the vicinity.
"Quantitative imaging produces a surface radioactivity distribution that can be converted to show dosage on the ground," says Tanimori. "The ETCC makes true images of the gamma rays based on proper geometrical optics."
This distribution can then be used to relatively easily measure ground dosage levels, showing that most gamma rays scatter and spread in the air, putting decontamination efforts at risk.
"Our ETCC will make it easier to respond to nuclear emergencies," continues Tanimori. "Using it, we can detect where and how radiation is being released. This will not only help decontamination, but also the eventual dismantling of nuclear reactors."

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Story Source:
Materials provided by Kyoto University. Note: Content may be edited for style and length.

All in the Wrist: Smart Jacket Houses Touch-Screen Tech

 

The jean jacket is getting a 21st-century upgrade: Levi's and Google are planning to launch a new "smart" jacket later this year, according to news reports.

The companies' so-called Project Jacquard was first announced in June 2015 as a line of "connected" clothing that would interact with wearers' smartphones, reported Tech Times. The so-called Commuter Jacket was unveiled in May 2016, and Levi's and Google revealed more details about the smart jacket project this weekend at the South by Southwest (SXSW) festival, Tech Times said. The companies said the jacket will cost $350 and will be available this fall.

The garment can interact with a person's smartphone via Bluetooth technology.  Conductive fabric on the connected jacket's wrist acts as a control panel for the wearer's smartphone.

In a video about Project Jacquard, Ivan Poupyrev, technical program lead at Google's Advanced Technology and Projects (ATAP) group, explained how the jacket works. Conductive threads have replaced some of a textile's original threads, so the woven-in technology can recognize simple touch gestures — similar to what a touch screen does, Poupyrev said.

"The tech is becoming a design element like a zipper, so it can be used in many normal ways," Poupyrev said during the SXSW presentation, reported Ars Technica. "I believe this is going to be the first commercial product which takes the touch interaction of the screen and puts it on an actual product."

Wearers can use the smart jacket to answer incoming calls, change music or get directions, said a promotional video made by Levi's. The Bluetooth device is attached to the garment as a cuff and connects the 15 conductive threads to the wearer's smartphone; batteries for the device are designed to last about two days.

Other than the conductive fabric and Bluetooth cuff, the jacket looks like a standard denim Levi's piece. It's even washable, Engadget said, as long as the Bluetooth cuff isn't attached.

Source- www.livescience.com

Lighting Design Calculation in a building

In professional field proper lighting design is very important because an under lighting arrangement will decrease the efficiency of the task for which the lightings were designed and an over lighting arrangement will result in over expenditure of the company. On small scale this difference is not too much to worry about but in large buildings, plants, factories, etc it becomes very significant in today electrical wiring installations.

The simple and basic approach for calculating the lighting requirement is to divide the total light requirement of the room by light output (lumen) provided by a single lamp. Although this is the basic approach for an average household room, but it’s not practically accurate.

In practical there are several other parameters which are necessary to be considered in the calculation because nothings Ideal. For example the luminaries lumen output won’t be the same throughout the entire life span, dust deposition on lamps will also reduce their output over time which means cleanliness is also an important parameter. A bright painted room reflects more light than a dark coloured room so they both have different lighting requirements.

So it is important to first understand few basic terms about lighting design before beginning the calculations.

Room Index- It is based on shape and size of the room. It describes the ratios of the room’s length, width and height. It’s usually between 0.75 to 5.

Where “l ” is the length of the room,

“w” is the width of the room and,

h_wc is height between work plane i.e. Bench to Ceiling

This formula for Room Index is applicable only when room length is less than 4 times the width.

Maintenance Factor:

It is ratio of the lamp lumen output after a particular interval of time as compared to when it was new. The lumen output of a light fitting decreases with time because of aging of many of its components by internal (saturation of elements) or external factors (dust deposition). For example maintenance factor of a light fitting used in a cool dust free area will be better than the light fitting used in hot and dusty area.

It is less than or equal to 1.

Typical values used for the lighting calculation are:

• 0.8 – For offices/classroom
• 0.7 – For clean Industry
• 0.6 – For dirty Industry

Room Reflections

The room is considered to consist of three main surfaces:

1. The ceiling
2. The walls
3. The floor

The effective reflectance’s of these 3 surfaces affect the quantity of reflected light received by the working plane. Light colors like white, yellow will have more reflectance compared to dark colors like blue, brown.

Utilization Factor

Utilization factor (UF) is the ratio of effective luminous flux to the total luminous flux of light sources. It is the measure of the effectiveness of the lighting scheme.

It depends upon

• The efficiency of luminaire
• The luminaire distribution
• The geometry of the space
• Room reflectance’s
• Polar curve

Space to Height ratio

It is the ratio of distance between adjacent luminaires (centre to centre) to their height above the working plane.

Where,

• H_m = Mounting height
• A = Total floor area
• N = No. of Luminaires

It should not exceed maximum SHR of the luminaire as provided by the manufacturer.

Note: A normal living room requires 20 lm/ft² i.e. 215 lm/m²

For Studying room i.e. Classroom 300 lm/m² is required.

(Note that for different environment and conditions there are different standards. For example companies like many MNC’s should maintain 600 lm/m² in the Office’s for people working in night shifts)

Now let’s start with the steps. Consider the following layout of a particular floor of the School and analyse the lighting requirements of different sections of the floor.

For ease of the calculation all the light fittings and their ratings taken into account are of Phillips make. You can check the various fixtures and their specification here provided by Philips.

Lighting Design Calculation for Classroom

Cross section area of classroom = 6×9 = 54 m², h = 3m

Lumens required = 54×300 = 16200 lm

The below table is a reference table for calculating Utilisation factor for light fittings. It differs from model to model and make to make. For just understanding the concept we are using a single reference table for all the light fittings. The actual table is provided by the manufacturer and can be little different from the one below.

Room Reflectance			Room Index
C	W	F	0.75	1	1.25	1.50	2.00	2.50	3.00	4.00	5.00
0.70	0.50	0.20	0.43	0.49	0.55	0.60	0.66	0.71	0.75	0.80	0.83
	0.30		0.35	0.41	0.47	0.52	0.59	0.65	0.69	0.75	0.78
	0.10		0.29	0.35	0.41	0.46	0.53	0.59	0.63	0.70	0.74
0.50	0.50	0.20	0.38	0.44	0.49	0.53	0.59	0.63	0.66	0.70	0.73
	0.30		0.31	0.37	0.42	0.46	0.53	0.58	0.61	0.66	0.70
	0.10		0.27	0.32	0.37	0.41	0.48	0.53	0.57	0.62	0.66
0.30	0.50	0.20	0.30	0.37	0.41	0.45	0.52	0.57	0.60	0.65	0.69
	0.30		0.28	0.33	0.38	0.41	0.47	0.51	0.54	0.59	0.62
	0.10		0.24	0.29	0.34	0.37	0.43	0.48	0.51	0.56	0.59
0.00	0.00	0.00	0.19	0.23	0.27	0.30	0.35	0.39	0.42	0.46	0.48

source: http://www.electricaltechnology.org