Tag Archives: light

Experiencing silence

Here is the second in a series of reprints while I am on vacation.  This one is from five years ago. It was published on August 9th 2017 under the title ‘Blinded by the light‘.

It has become a habit during our summer vacation to read the novels short-listed for Bailey’s Women’s Prize for Fiction.  Unusually this year, we were not only unanimous in our choice of the best novel but we also agreed with the judges and selected the ‘The Power‘ by Naomi Alderman.  In another of the books, Do Not Say We Have Nothing by Madeleine Thien, a Chinese composer called Sparrow thinks ‘about the quality of sunshine, that is, how daylight wipes away the stars and planets, making them invisible to human eyes, might daylight be a form of blindness? Could it be that sound was also be a form of deafness? If so, what was silence?’.  I felt some resonance between these thoughts and John Hull’s writings on blindness and my earlier blog posting on ‘Listening with your eyes shut‘ [on May 31st, 2017].  In our everyday life, we are bombarded with sounds from people living around us, from traffic and from devices in our homes and places of work.  We rarely experience silence; however, when we do, perhaps on holiday staying in a remote rural location, then a whole new set of sounds becomes apparent: waves breaking on the shore in the distance, the field mouse rooting around under the floorboards, or the noises of cattle enjoying the lush grass in the field next door.  Okay, so you have to be in the right place to hear these sounds of nature but you also need silence otherwise you are deaf to them, as Sparrow suggests.

The same is true for knowledge and understanding because our minds have finite capacity [see my post entitled ‘Silence is golden‘ on January 14th, 2014].  When you are bombarded with information and data it is easy to become overwhelmed and unable to structure the information in a way that makes it useful or meaningful.  In our connected society, information has become like white noise, or daylight obscuring the stars and planets.  Information is blinding us to knowledge and understanding.  We need to aggressively filter the information flow in order to gain insight and knowledge.  We should switch off the digital devices, which bombard us with information constantly, to leave our minds free for conceptual and creative thinking because that’s one of the few tasks in which we can outperform the smartest machine [see my post entitled ‘Smart machines‘ on February 26th, 2014].

In a similar vein see: ‘Ideas from a balanced mind‘ on August 24th, 2016 and ‘Thinking out-of-the-skull‘ on March 18th, 2015.

Going against the flow

Decorative photograph of a mountain riverLast week I wrote about research we have been carrying out over the last decade that is being applied to large scale structures in the aerospace industry (see ‘Slowly crossing the valley of death‘ on January 27th, 2021). I also work on very much smaller ‘structures’ that are only tens of nanometers in diameter, or about a billion times smaller than the test samples in last week’s post (see ‘Toxic nanoparticles?‘ on November 13th, 2013). The connection is the use of light to measure shape, deformation and motion; and then utilising the measurements to validate predictions from theoretical or computational models. About three years ago, we published research which demonstrated that the motion of very small particles (less than about 300 nanometres) at low concentrations (less than about a billion per millilitre) in a fluid was dominated by the molecules of the fluid rather than interactions between the particles (see Coglitore et al, 2017 and ‘Slow moving nanoparticles‘ on December 13th, 2017). This data confirmed results from earlier molecular dynamic simulations that contradicted predictions using the Stokes-Einstein equation, which was derived by Einstein in his PhD thesis for a ‘Stokes’ particle undergoing Brownian motion. The Stokes-Einstein equation works well for large particles but the physics of motion changes when the particles are very small and far apart so that Van der Waals forces and electrostatic forces play a dominant role, as we have shown in a more recent paper (see Giorgi et al, 2019).  This becomes relevant when evaluating nanoparticles as potential drug delivery systems or assessing the toxicological impact of nanoparticles.  We have shown recently that instruments based on dynamic scattering of light from nanoparticles are likely to be inaccurate because they are based on fitting measurement data to the Stokes-Einstein equation.  In a paper published last month, we found that asymmetric flow field flow fractionation (or AF4)  in combination with dynamic light scattering when used to detect the size of nanoparticles in suspension, tended to over-estimate the diameter of particles smaller than 60 nanometres at low concentrations by upto a factor of two (see Giorgi et al, 2021).  Someone commented recently that our work in this area was not highly cited but perhaps this is unsurprising when it undermines a current paradigm.  We have certainly learnt to handle rejection letters, to redouble our efforts to demonstrate the rigor in our research and to present conclusions in a manner that appears to build on existing knowledge rather than demolishing it.

Sources:

Coglitore, D., Edwardson, S.P., Macko, P., Patterson, E.A. and Whelan, M., 2017. Transition from fractional to classical Stokes–Einstein behaviour in simple fluids. Royal Society open science, 4(12), p.170507.

Giorgi, F., Coglitore, D., Curran, J.M., Gilliland, D., Macko, P., Whelan, M., Worth, A. and Patterson, E.A., 2019. The influence of inter-particle forces on diffusion at the nanoscale. Scientific reports, 9(1), pp.1-6.

Giorgi, F., Curran, J.M., Gilliland, D., La Spina, R., Whelan, M.P. & Patterson, E.A. 2021, Limitations of nanoparticles size characterization by asymmetric flow field-fractionation coupled with online dynamic light scattering, Chromatographia, doi.org/10/1007/s10337-020-03997-7.

Image is a photograph of a fast flowing mountain river taken in Yellowstone National Park during a roadtrip across the USA in 2006.