Convert Time \(t\) into Variable Linearly Depending on \(t\).

Conversion of time (\(t\)) into variable (\(var\)) which is linearly changed on time.

Usage

convert_time2var(
  time.vals,
  time.unit = "s",
  var0,
  var.switch = NULL,
  var.rate,
  var.rate.unit = "s^{-1}"
)

Arguments

time.vals

Numeric value or vector, corresponding to time (points) where the variable var is changed.

time.unit

Character string, time unit defined by s,min or h. Default: time.unit = "s".

var0

Numeric, the initial value (ALSO WITH NEGATIVE SIGN, if required, e.g. negative electrochemical potential).

var.switch

Numeric, the switching point var value, in case when a linear CYCLIC CHANGE (or 'triangular ramp') of var on time is applied (e.g. in cyclic voltammetry). Default: var.switch = NULL (in case there is no such cyclic change).

var.rate

Numeric, corresponding to rate of linear var change (INCLUDING ALSO NEGATIVE SIGN, if required, e.g. in the case of electrochemical reduction or sample cooling).

var.rate.unit

Character string, corresponding to var.rate unit defined by following strings "s^{-1}" \(\equiv \text{s}^{-1}\), "min^{-1}" \(\equiv \text{min}^{-1}\) or "h^{-1}" \(\equiv \text{h}^{-1}\). Default: var.rate.unit = "s^{-1}".

Value

Numeric value or vector of the variable such as electrochemical potential or temperature, linearly changing on time.

Details

The linear time change of \(var\) can be expressed like $$var = var0 + rate~ t$$ This is especially suitable for time conversion of EPR time series experiments (see e.g. readEPR_Exp_Specs_kin) simultaneously performed either during electrochemical/voltammetric or variable temperature experiment. When cyclic series experiment is performed (e.g. cyclic voltammetry), that \(var\) value depends on the switching one, like => $$var = var0 + rate~ t ~~ \text{for} ~~ t \leq t_{\text{switch}}$$ $$var = var_{\text{switch}} - rate\, (t - t_{\text{switch}}) ~~ \text{for} ~~ t \geq t_{\text{switch}}$$ where the \(t_{\text{switch}}\), corresponding to \(var_{\text{switch}}\), are the quantities at the turning point( see also var.switch argument).

See also

Other Conversions and Corrections: convert_A_MHz_2a(), convert_B(), convert_a_mT_2A(), correct_time_Exp_Specs()

Examples

## calculate potential after 30 s, starting from 200 mV
## into cathodic direction (reduction) by 5 mV s^{-1}
convert_time2var(30,var0 = 0.2,var.rate = - 0.005)
#> [1] 0.05
#
## heating sample after 5 min starting from 293 K
## by the temperature rate of 4 K min^{-1}
convert_time2var(5,
                 time.unit = "min",
                 var0 = 293,
                 var.rate = 4,
                 var.rate.unit = "min^{-1}")
#> [1] 313
#
## create/evaluate vector containing the applied
## cell potential (in V) from the simultaneously
## performed electrochemical oxidation experiment
## (e.g. cyclic voltammetry from -0.1V to 0.45V and back
## to -0.1V). Time series vector is labeled as "time_s".
time_s <- seq(0,360,by = 18)
E_V <- convert_time2var(time.vals = time_s,
                        var0 = -0.1,
                        var.switch = 0.45,
                        var.rate = 0.003)
## preview
as.matrix(E_V)
#>         [,1]
#>  [1,] -0.100
#>  [2,] -0.046
#>  [3,]  0.008
#>  [4,]  0.062
#>  [5,]  0.116
#>  [6,]  0.170
#>  [7,]  0.224
#>  [8,]  0.278
#>  [9,]  0.332
#> [10,]  0.386
#> [11,]  0.440
#> [12,]  0.406
#> [13,]  0.352
#> [14,]  0.298
#> [15,]  0.244
#> [16,]  0.190
#> [17,]  0.136
#> [18,]  0.082
#> [19,]  0.028
#> [20,] -0.026
#> [21,] -0.080