23 jun. 2013

Score Matrix "T" in 3D

We have seen the score matrix, several times in this blog. Now, I create a vector with the scores values for every sample for the first 3 Principal components, or Loadings.
Tcomp1<-T[,1]  ........................T values for the first PC
Tcomp2<-T[,2]  ........................T values for the second PC
Tcomp3<-T[,3]  ........................T values for the third PC

Now there are diferent options to see this T matrix in 3D:
One of them can be:
library(scatterplot3d)scatterplot3d(Tcomp1,Tcomp2,Tcomp3)
 and we get a plot.

Other way is to use the package:
library(rgl)
plot3d(Tcomp1,Tcomp2,Tcomp3,col="red",size=5)

We can move the plot with the mouse and see the different faces of the cube. 

19 jun. 2013

"II Jornada NIR" - Trouw Nutrition - Masterlab


 
 Hoy  he participado como ponente en las "II Jornadas NIR" organizadas por Trouw Nutrition y Masterlab España con una ponencia sobre "Fundamentos de la Tecnología NIR" y "Buenas Prácticas en el uso del NIR". Aparte de como ponente el resto de las Jornadas, estuve muy atento a las distintas ponencias de Oscar Benito (Responsable NIR de Masterlab España), Javier Lallana (Jefe de Laboratorio de Masterlab España), Angela Gutierrez (ASC Nutreco), Dña Elena Albanell (UAB de Barcelona) y Dña Begoña de la Roza (Responsable del centro SERIDA).
D. Angel Sacristan (Director de Masterlab España) hizó una interesante introducción de Trouw Nutrition y Masterlab España que son sin duda empresas pioneras en el uso del NIR, y que actualmente disponen de una impresionante Red de equipos NIR conectados a traves de la plataforma RINA .
Sus proyectos para el futuro son sin duda muy interesantes y de mucho crecimiento a nivel Nacional e Internacional.
Gracias a Trouw, Masterlab y FOSS por permitirme asistir con una ponencia .
 

11 jun. 2013

Video: Movimiento Armónico Simple

Estos días estoy preparando una ponencia y presentación sobre los fundamentos teóricos del NIR, y siempre es interesante repasar estos videos, pues el movimiento armónico simple es la base para entender la vibración molecular y toda su aplicación en el Infrarrojo Medio (MIR) y en el Infrarrojo Cercano (NIR). Espero, cuando ya la tenga completada compartirla con los lectores del blog.

Otros videos a repasar son:

William Herschell experiment
Video: Middle Infrared (MIR) Theory Fundamentals
Vibración Molecular (Infrarrojo Medio)
Ley de Hooke (Walter Lewin)

y algunos otros posts con la etiqueta Fundamentos

10 jun. 2013

Working in transflectance


In the case of  some liquid and viscous samples when the light (in the case of this post-dispersive NIR instrument) cross the samples, we can lose a lot of energy (transmited light which does not reach the detectors)
 See this case (in the reallity is not so much light, because the photograph over-exposed the core of light)  looking the sample from the top side:
 
so maybe it become necessary a reflector, to work in transflectance. Video show how the reflector is placed over the sample cup looking from the down side.
When doing this take care that not bubbles or any other non desired material is on the pathlength under the reflection area.
 
video
 
In the case of chocolat it is not necessary to use the reflector:
 
 
 

6 jun. 2013

Definitions to describe process control

off-line -  Manual sampling from the process sent to the laboratory for NIR  analysis. In this case (normally) one or a few samples are analyzed for every batch, and when we get the result it can be late to change  the regulation of the process, with all the disadvantages that it means (re-process all the batch,.....).


at-line - Manual sampling from the process analysed in a NIR, sited close to the production line. It is normally used by the plant operators. It can be installed in the process control room, and the operators scan samples when they (based on their experience in the process) consider. Response to problems in the process is quicker than in the off-line case.
on-line - Automated sampling sent  through a sample line (by-pass) to be analyzed by a process NIR. This system is more used in liquids where there are a lot of issues related to the pressure, vacuum, and requires of a well design of the bypass to remove bubbles and other problems to get a representative spectrum.
We can use this system to carry flour or feed, by gravity to a bypass cell (when a valve opens) this way it can be analyzed in transmittnce or reflectance  after the analysis another other two valves can open, one in case we want ro return the sample to the process pipe or other to take out the sample for laboratory reference analysis. This can be a way to get a more representative sample with more correlation with the spectra acquired, but the disadvantage is that the percentage of sample analyzed for the batch  is less than in the in-line system.
in-line - A fiber optic probe connected to a process NIR, and inserted into the process line (Reactor, pipes,..), it can work in transmitance or transflectance . It can be also a process  NIR window placed in the process line  to work in difusse reflectance.