R/workingon.R

In JARS3N/timeconstant: timeconstant

rm_deadspace <- function(file) {
  x <-setNames(
    read.csv(file, skip = 4)[c("Time.sec.", "High.CHpH")],
   c("Time", "counts"))
  x$diff <- c(0, diff(x$counts))
  injection_at <- which(x$diff == min(x$diff)) - 3
  x <- x[-1 * (1:injection_at), ]
  x$Time <- x$Time - x$Time[1]
  x$file<-basename(file)
  x[c("Time","counts","file")]
}


TC_adj<-function(Time,counts){
# data capture@500ms, therefore
# using datapoint 61 as approx period of 30 seconds
period <- Time[61] 
deltaP <- counts[1] - counts[61]
deltaT<- min_mean_5(counts)
tau(period,deltaP,deltaT)
}

tau<-function(period,deltaP,deltaT){
abs(period/(log(1/(1 - (deltaP/deltaT)))))
}

min_mean_5<-function(U,n=5){
  i<-seq_along(U)
  A<-na.omit(lag(i,n-1))
  B<-na.omit(lead(i,n-1))
  mapd<-mapply(function(A,B){mean(U[A:B])},A,B)
  min(mapd)
}