Sunday, November 12, 2017

Identifying moldy fruit in the refrigerator

Moldy black raspberry

Keeping fruit fresh in a refrigerator is a challenge.  These black raspberries became moldy after less than a week in a refrigerator.  Most of the mold on the surface was mycelia without reproductive structures.  I used a clear 3M transparent tease tape and with a 85% lactic acid mixed with fuchsin dye to identify the organism under 400x power.
Low resolution photomicrograph of Botrytis spp.  - N. Carlson

Close up of Botrytis spp. growing on the black raspberries - N. Carlson 

Photomicrograph of Cladosopoium spp. growing on the black raspberries. - N. Carlson

Identifying moldy vegetables in the refrigerator

Moldy red pepper - N. Carlson

With a microscope at home it's fun  to check on what's growing items that have gone way beyond the best by date.  These red peppers were in a closed container for more than a couple weeks.  The primary organisms identified were yeast and the dark colored Cladosporium spp. The Fridge temperature was reading 36 degrees F. or a 2.2 degrees C.

Yeast - N. Carlson
Cladosporium spp. - N. Carlson

Sunday, October 8, 2017

IAQ radio interview with Andrew Streifel U of MN

Andrew Streifel - N. Carlson
I've had the pleasure to work with Andrew Streifel for over 30 years, first as a graduate student and then as a co-worker at the University of Minnesota Department of Environmental Health and Safety.  He is a prolific author of journal articles, an excellent speaker and the go to consultant for hospitals around the world when they are trying to solve a difficult infection control problem.

In the summer of 2017, he was interviewed on IAQ Radio discussing aspects of health care acquired infections, formerly known as nosocomial or hospital acquired infections.  In IAQ Radio Episode 470 Andrew Streifel, he reviewed the major areas of concern including infection sources, sampling methods and case studies of patient infections.

This is a list of just some of the factors mentioned that contribute to health care acquired infections:
  • The clothing worn by guests visiting a patient can be contaminated with spores from the outdoor air.
  • The previous occupant of a patient care room may pass their infection onto the next patient. Therefore, the quality of surface decontamination between patients is critical. 
  • Improper installation of building filters allows outside air to by pass the filters. 
  • A negatively pressurized building can bring in unfiltered air into the patient care area. 
I hope you get a chance to listen to the full interview. It provides many helpful suggestions for investigating health care acquired infections.

Andrew Streifel on IAQ Radio - 1 hour

Sunday, August 13, 2017

Flir-one pro IR camera

Photo of a slot supply diffuser with two small water leaks in blue on the lower right - N. Carlson
I have been pleased with the original FLIR ONE IR cell phone camera attachment and decided to upgrade to the FLIR ONE PRO as the resolution was increased by a factor of four and the upper end of the temperature range increased to 400C.  

Notes: The Android phone adapter is a C connection which has a benefit in that the camera can be orientated front or back.  The attachment will require an adapter for older phones like the Samsung J7 or the S5. The type of adapter will depend on the type of phone.  After my first attempt at purchasing an adaptor failed, I contacted FLIR and they identified the specifications for the adaptor.  I needed an Type C OTG Adapter, USB C Female to Micro USB Male OTG (On the Go) Converter Charging Data Sync Adapter . It cost less than $10. 

Issues: The FLIR ONE app will occasionally freeze up or fail to recognize the attached camera.  This problem has become less common the more I use the camera.  The new FLIR ONE app is better than the original with some helpful videos on areas where the camera may be useful.  The variety of color pallets for viewing the image provides a way of selecting the best color temperature contrast. 

Supply air diffuser with spot temperature read out.  - N. Carlson
There will be more posts in the future as I get to know the instrument better.   

Cherry mold

Mold growth on red cherry - N.Carlson
Never pass up an opportunity to identify mold on food.  I purchased a bag of cherries a couple of days ago at a local grocery store.  The rest of the fruit I examined did not show mold growth.

I used a clear 3M red tartan Scotch tape with 85% lactic acid mixed with a small amount of lacto fuchsin stain. The photos were taken with a Samsung J7 camera using an AmScope microscope.

Growth of Alternaria spp. and Cladosporium spp. taken from a tease tape sample of the cherry - 400x - N. Carlson
This would be a fairly easy mold to identify for an introductory mold class.

Monday, June 5, 2017

Handwashing guidelines for Farms, Fairs, and Fun

Handwashing is important to minimize the spread of  germs when visiting a farm or a petting zoo this summer.  Information below is provided from UMASH and the Minnesota Department of Health. This UMASH site links to a printable pdf of the poster Don't Spread Germs - Wash Your Hands!

Handwashing video of approximately 2 and 1/2 minutes

Friday, June 2, 2017

Sunday, March 12, 2017

Water leak detection with FLIR one IR camera

IR image reveals blue areas noting water damage near bathroom water leak - N. Carlson

Infrared photo to the right of the door - N. Carlson
Part of the base cove has been removed in this photo to check for water damage.  Note that water damage is suggested by the lighter blue color in this FLIR one image in areas further to the right where the base cove has not been removed.

IR photo of same wall with a different color contrast - N. Carlson

Infrared imaging helps explain location of fungal growth on exterior wall

Flir One infrared image of exterior wall Feb 2017 - N. Carlson
The blue and purple colored areas are colder than the yellow and red areas on this infrared photo taken with a FLIR One infrared camera attached to a Samsung cellphone.

Dark areas of mold growth on an exterior sheetrock wall.
The space was used to store books and other materials.  The interior relative humidity was measured at 46%.  This allowed for condensation on the metal roof deck and for the equilibrium relative humidity on the sheetock over the metal studs to be greater than 70%. 

Energy collecting windows - U of Minnesota research

Luminescent Solar Concentrator - Steven Shimizu

Current silicon solar cells have an efficiency of 25%.  These cells are opaque (do not allow light to transmit through). Please see Standard silicon solar cell parameters (PV

In a luminescent solar collector, the quantum silicon dots embedded or painted on transparent glass reflect light to the perimeter of the glass where solar collectors convert the light into energy.  This allows a window in a building to also work as a solar collector. Because silica is not an element in short supply, this allows for low cost and low efficiency (2.5 to 5%) solar energy collection. 
The U of M Brief publication article on Energy Collecting Windows now a Step Closer to Reality 
describes the process researchers used to construct the window based solar collectors. The abstract,
Highly efficient luminescent solar concentrators based on earth-abundant indirect-bandgap silicon quantum dots provides more information.  

The Clean Energy Institute lists resources and materials needed to construct a Luminescent Solar Concentrator.

Windows that collect solar energy - 2 min.