diff --git a/julia/TUG/docs/make.jl b/julia/TUG/docs/make.jl
index ca0b84a..a334bba 100644
--- a/julia/TUG/docs/make.jl
+++ b/julia/TUG/docs/make.jl
@@ -2,12 +2,12 @@ using Pkg
 using Documenter
 
 pkg_path = abspath(joinpath(@__DIR__, ".."))
-Pkg.develop(path=pkg_path)
+Pkg.develop(path = pkg_path)
 using TUG
 
 makedocs(
-    sitename="TUG Documentation",
-    modules=[TUG],
-    format=Documenter.HTML(),
-    remotes=nothing
+    sitename = "TUG Documentation",
+    modules = [TUG],
+    format = Documenter.HTML(),
+    remotes = nothing,
 )
diff --git a/julia/TUG/src/Boundary.jl b/julia/TUG/src/Boundary.jl
index 4dac5d4..0d75f20 100644
--- a/julia/TUG/src/Boundary.jl
+++ b/julia/TUG/src/Boundary.jl
@@ -46,10 +46,7 @@ struct BoundaryElement{T}
     end
 
     function BoundaryElement{T}(value::T)::BoundaryElement{T} where {T}
-        if value < 0
-            throw(ArgumentError("No negative concentration allowed."))
-        end
-        new{T}(CONSTANT, value)
+        new{T}(TUG.CONSTANT, value)
     end
 end
 
@@ -114,14 +111,14 @@ It includes the dimension of the grid and boundary elements for each side.
 """
 struct Boundary{T}
     dim::UInt8
-    cols::UInt32
     rows::UInt32
+    cols::UInt32
     boundaries::Vector{Vector{BoundaryElement{T}}}
 
     function Boundary{T}(grid::Grid{T})::Boundary{T} where {T}
         dim = grid.dim
-        cols = grid.cols
         rows = grid.rows
+        cols = grid.cols
         boundaries = Vector{Vector{BoundaryElement{T}}}(undef, 4)
 
         if dim == 1
@@ -136,7 +133,7 @@ struct Boundary{T}
             throw(ArgumentError("Only 1- and 2-dimensional grids are defined!"))
         end
 
-        new{T}(dim, cols, rows, boundaries)
+        new{T}(dim, rows, cols, boundaries)
     end
 end
 
diff --git a/julia/TUG/src/TUG.jl b/julia/TUG/src/TUG.jl
index 448dd97..403b9c1 100644
--- a/julia/TUG/src/TUG.jl
+++ b/julia/TUG/src/TUG.jl
@@ -9,14 +9,14 @@ export clone,
     getAlphaX_t,
     getAlphaY_t,
     getConcentrations,
-    setConcentrations!,
-    setAlphaX!,
-    setAlphaY!,
     getDomainCol,
     getDomainRow,
     getDeltaCol,
     getDeltaRow,
-    getDim
+    getDim,
+    setAlphaX!,
+    setAlphaY!,
+    setConcentrations!
 
 include("Boundary.jl")