diff --git a/src/JuliaFEM.jl b/src/JuliaFEM.jl
index f03d5ca..7d679d3 100644
--- a/src/JuliaFEM.jl
+++ b/src/JuliaFEM.jl
@@ -12,8 +12,6 @@ include("fields.jl")
 export Field, DCTI, DVTI, DCTV, DVTV, CCTI, CVTI, CCTV, CVTV
 include("types.jl")  # data types: Point, IntegrationPoint, ...
 export AbstractPoint, Point, IntegrationPoint, IP, Node
-#include("basis.jl")  # interpolation of discrete fields
-#include("symbolic.jl") # a thin symbolic layer for fields
 
 ### ELEMENTS ###
 include("elements.jl") # common element routines
@@ -114,11 +112,11 @@ export aster_create_elements, parse_aster_med_file, is_aster_mail_keyword,
        filter_by_element_set, filter_by_element_id, MEDFile
 end
 
-function get_mesh(mesh_name::ASCIIString, args...; kwargs...)
+function get_mesh(mesh_name::String, args...; kwargs...)
     return get_mesh(Val{Symbol(mesh_name)}, args...; kwargs...)
 end
 
-function get_model(model_name::ASCIIString, args...; kwargs...)
+function get_model(model_name::String, args...; kwargs...)
     return get_model(Val{Symbol(model_name)}, args...; kwargs...)
 end
 
diff --git a/src/api_functions.jl b/src/api_functions.jl
index a80380b..74b38d9 100644
--- a/src/api_functions.jl
+++ b/src/api_functions.jl
@@ -8,7 +8,7 @@ end
 """
 Add node to model and renumber for output
 """
-function add_node!(model::Model, index::Union{Int64, ASCIIString},
+function add_node!(model::Model, index::Union{Int64, String},
     coords::Vector{Float64})
     node = Node(index, coords)
     model.nodes[index] = node
@@ -25,7 +25,7 @@ function add_solver!(case::Simulation, solver)
     case.solver = solver
 end
 
-function add_material!(model::Model, set_name::ASCIIString, material::Material)
+function add_material!(model::Model, set_name::String, material::Material)
     element_set = model.elsets[set_name]
     set_ids = element_set.elements
     for each in set_ids
@@ -35,7 +35,7 @@ function add_material!(model::Model, set_name::ASCIIString, material::Material)
     element_set.material = material
 end
 
-function add_element!(model::Model, idx::Union{Int64, ASCIIString},
+function add_element!(model::Model, idx::Union{Int64, String},
     eltype::Symbol, node_ids::Vector{Int64})
 
     element = Element(idx, node_ids, eltype)
@@ -47,27 +47,27 @@ function add_element_set!(model::Model, elset::ElementSet)
     model.elsets[name] = elset
 end
 
-function add_element_set!(model::Model, name::ASCIIString, ids::Vector{Int64})
+function add_element_set!(model::Model, name::String, ids::Vector{Int64})
     elset = ElementSet(name, ids)
     model.elsets[name] = elset
 end
 
-function add_node_set!(model::Model, name::ASCIIString, ids::Vector{Int64})
+function add_node_set!(model::Model, name::String, ids::Vector{Int64})
     nset = NodeSet(name, ids)
     model.nsets[name] = nset
 end
 
-function add_element_set!(model::Model, name::ASCIIString,
+function add_element_set!(model::Model, name::String,
     elements::Vector{Element})
     elset = ElementSet(name, elements)
 model.elsets[name] = elset
 end
 
-function add_element_set!(case::Simulation, name::ASCIIString)
+function add_element_set!(case::Simulation, name::String)
     push!(case.sets, name)
 end
 
-function add_simulation!(model::Model, name::ASCIIString, case::Simulation)
+function add_simulation!(model::Model, name::String, case::Simulation)
     model.load_cases[name] = case
 end
 #function Base.convert{T<:AbstractFloat}(::Type{Node}, data::Vector{T})
@@ -80,7 +80,7 @@ end
 #end
 #
 #
-#function get_element_set(model::Model, set_name::ASCIIString)
+#function get_element_set(model::Model, set_name::String)
 #    get_set = model.sets[set_name]
 #    isa(get_set, ElementSet) ? get_set : err("Found set $(set_name)
 #    but it is not a ElementSet. Check if you have used
diff --git a/src/api_types.jl b/src/api_types.jl
index fc60d6d..0831902 100644
--- a/src/api_types.jl
+++ b/src/api_types.jl
@@ -3,12 +3,12 @@
 
 
 type NeumannBC
-    set_name :: ASCIIString
+    set_name :: String
     value :: Any
 end
 
 type DirichletBC 
-    set_name :: ASCIIString
+    set_name :: String
     value :: Any
 end
 
@@ -21,13 +21,13 @@ typealias HeatFluxBC NeumannBC
 """
 """
 type Material
-    name :: ASCIIString
-    scalar_data :: Dict{ASCIIString, Any}
+    name :: String
+    scalar_data :: Dict{String, Any}
 end
 
 #Material(name, data) = Material(name, Dict(data))
-Material(name) = Material(name, Dict{ASCIIString, Any}())
-Material() = Material("", Dict{ASCIIString, Any}())
+Material(name) = Material(name, Dict{String, Any}())
+Material() = Material("", Dict{String, Any}())
 
 function Base.setindex!{T <: AbstractString }(material::Material, val, name::T)
     material.scalar_data[name] = val 
@@ -35,12 +35,12 @@ end
 
 
 type Node 
-    id :: Union{Integer, ASCIIString}
+    id :: Union{Integer, String}
     coords :: Array{Float64, 1}
 end
 
 type Element
-    id :: Union{Integer, ASCIIString, Void}
+    id :: Union{Integer, String, Void}
     connectivity :: Vector{Int64}
     element_type :: Symbol
     results :: Any # Dict{}
@@ -50,22 +50,22 @@ end
 Element(a, b, c) = Element(a, b, c, nothing, Material())
 
 type NodeSet
-    name :: ASCIIString
+    name :: String
     nodes :: Vector{Int64}
 end
 
 """
 """
 type ElementSet
-    name :: ASCIIString
-    elements :: Vector{Union{Int64, ASCIIString}} 
+    name :: String
+    elements :: Vector{Union{Int64, String}} 
     material :: Material
 end
 
-ElementSet(name::ASCIIString, elements::Vector{Element}) =
+ElementSet(name::String, elements::Vector{Element}) =
     ElementSet(name, map(x-> x.id, elements), Material())
 
-ElementSet(name::ASCIIString, ids::Vector{Int64}) =
+ElementSet(name::String, ids::Vector{Int64}) =
     ElementSet(name, ids, Material())
 
 """
@@ -76,10 +76,10 @@ type Simulation
     neumann_boundary_conditions :: Vector{NeumannBC}
     dirichlet_boundary_conditions :: Vector{DirichletBC}
     solver
-    sets :: Vector{ASCIIString}
+    sets :: Vector{String}
 end
 
-Simulation(a) = Simulation(a, NeumannBC[], DirichletBC[], nothing, ASCIIString[])
+Simulation(a) = Simulation(a, NeumannBC[], DirichletBC[], nothing, String[])
 
 
 """
@@ -88,17 +88,17 @@ Model type
 Used for constructing the calculation model
 """
 type Model
-    name :: ASCIIString 
-    nodes :: Dict{Union{Int64, ASCIIString}}
-    elements :: Dict{Union{ASCIIString, Int64}, Element} 
-    elsets :: Dict{ASCIIString, ElementSet}
-    nsets :: Dict{ASCIIString, NodeSet}
-    load_cases :: Dict{ASCIIString, Simulation}
-    renum_nodes :: Dict{Union{Int64, ASCIIString}, Int64}
+    name :: String 
+    nodes :: Dict{Union{Int64, String}}
+    elements :: Dict{Union{String, Int64}, Element} 
+    elsets :: Dict{String, ElementSet}
+    nsets :: Dict{String, NodeSet}
+    load_cases :: Dict{String, Simulation}
+    renum_nodes :: Dict{Union{Int64, String}, Int64}
     #settings :: Dict{AbstractString, Real}
 end
 
-function Model(name::ASCIIString, abq_input::Dict)
+function Model(name::String, abq_input::Dict)
     model  = Model(name)
     nodes        = abq_input["nodes"]
     elements     = abq_input["elements"]
@@ -129,18 +129,18 @@ function Model(name::ASCIIString, abq_input::Dict)
     model
 end
 
-Model(name::ASCIIString) = Model(
+Model(name::String) = Model(
     name,
-    Dict{Union{Int64, ASCIIString}, Node}(),
-    Dict{Union{Int64, ASCIIString}, Element}(),
-    Dict{ASCIIString, NodeSet}(),
-    Dict{ASCIIString, ElementSet}(),
-    Dict{ASCIIString, Simulation}(),
-    Dict{Union{Int64, ASCIIString}, Int64}()
+    Dict{Union{Int64, String}, Node}(),
+    Dict{Union{Int64, String}, Element}(),
+    Dict{String, NodeSet}(),
+    Dict{String, ElementSet}(),
+    Dict{String, Simulation}(),
+    Dict{Union{Int64, String}, Int64}()
 )
 
-function Base.setindex!(dict::Dict{Union{ASCIIString, Int64}, Node},
-    vals::Vector{Float64}, idx::Union{ASCIIString, Int64})
+function Base.setindex!(dict::Dict{Union{String, Int64}, Node},
+    vals::Vector{Float64}, idx::Union{String, Int64})
     dict[idx] = Node(idx, vals)
 end
 
diff --git a/src/elements.jl b/src/elements.jl
index 1538777..c5ff893 100644
--- a/src/elements.jl
+++ b/src/elements.jl
@@ -7,7 +7,7 @@ type Element{E<:AbstractElement}
     id :: Int
     connectivity :: Vector{Int}
     integration_points :: Vector{IP}
-    fields :: Dict{ASCIIString, Field}
+    fields :: Dict{String, Field}
     properties :: E
 end
 
@@ -17,27 +17,27 @@ function Element{E<:AbstractElement}(::Type{E}, connectivity=[], integration_poi
     return element
 end
 
-function getindex(element::Element, field_name::ASCIIString)
+function getindex(element::Element, field_name::String)
     return element.fields[field_name]
 end
 
-function setindex!(element::Element, data::Field, field_name::ASCIIString)
+function setindex!(element::Element, data::Field, field_name::String)
     element.fields[field_name] = data
 end
 
-function setindex!(element::Element, data, field_name::ASCIIString)
+function setindex!(element::Element, data, field_name::String)
     element.fields[field_name] = Field(data)
 end
 
-function call(element::Element, field_name::ASCIIString)
+function call(element::Element, field_name::String)
     return element[field_name]
 end
 
-function call(element::Element, field_name::ASCIIString, time)
+function call(element::Element, field_name::String, time)
     return element[field_name](time)
 end
 
-function last(element::Element, field_name::ASCIIString)
+function last(element::Element, field_name::String)
     return last(element[field_name])
 end
 
@@ -71,7 +71,7 @@ function call(element::Element, ip, time, ::Type{Val{:Grad}})
     return inv(J)*get_dbasis(element, ip, time)
 end
 
-function call(element::Element, field_name::ASCIIString, ip, time, ::Type{Val{:Grad}})
+function call(element::Element, field_name::String, ip, time, ::Type{Val{:Grad}})
     return element(ip, time, Val{:Grad})*element[field_name](time)
 end
 
@@ -83,14 +83,14 @@ function call(element::Element, field::DCTI, time)
     return field.data
 end
 
-function call(element::Element, field_name::ASCIIString, time)
+function call(element::Element, field_name::String, time)
     field = element[field_name]
-    return call(element, field, time)
+    return element(field, time)
 end
 
-function call(element::Element, field_name::ASCIIString, ip, time::Float64)
+function call(element::Element, field_name::String, ip, time::Float64)
     field = element[field_name]
-    return call(element, field, ip, time)
+    return element(field, ip, time)
 end
 
 function call(element::Element, field::DCTI, ip, time::Float64)
@@ -131,17 +131,17 @@ julia> update!(element, "geometry", data)
 As a result element now have time invariant (variable) vector field "geometry" with data ([0.0, 0.0], [1.0, 2.0]).
 
 """
-function update!(element::Element, field_name::ASCIIString, data::Dict)
+function update!(element::Element, field_name::String, data::Dict)
     element[field_name] = [data[i] for i in get_connectivity(element)]
 end
 
-function update!{K,V}(element::Element, field_name::ASCIIString, data::Pair{Float64, Dict{K, V}})
+function update!{K,V}(element::Element, field_name::String, data::Pair{Float64, Dict{K, V}})
     time, field_data = data
     element_data = V[field_data[i] for i in get_connectivity(element)]
     update!(element, field_name, time => element_data)
 end
 
-function update!(element::Element, field_name::ASCIIString, datas::Union{Real, Vector, Pair{Float64, Union{Float64, Real, Vector{Any}}}}...)
+function update!(element::Element, field_name::String, datas::Union{Real, Vector, Pair{Float64, Union{Float64, Real, Vector{Any}}}}...)
     for data in datas
         if haskey(element, field_name)
             update!(element[field_name], data)
@@ -155,13 +155,13 @@ function update!(element::Element, field_name::ASCIIString, datas::Union{Real, V
     end
 end
 
-function update!(element::Element, field_name::ASCIIString, datas::Pair...)
+function update!(element::Element, field_name::String, datas::Pair...)
     for data in datas
         update!(element, field_name, data)
     end
 end
 
-function update!(element::Element, field_name::ASCIIString, data::Pair{Float64, Vector{Any}})
+function update!(element::Element, field_name::String, data::Pair{Float64, Vector{Any}})
     if haskey(element, field_name)
         update!(element[field_name], data)
     else
@@ -169,7 +169,7 @@ function update!(element::Element, field_name::ASCIIString, data::Pair{Float64,
     end
 end
 
-function update!(element::Element, field_name::ASCIIString, data::Pair{Float64, Vector{Int64}})
+function update!(element::Element, field_name::String, data::Pair{Float64, Vector{Int64}})
     if haskey(element, field_name)
         update!(element[field_name], data)
     else
@@ -177,7 +177,7 @@ function update!(element::Element, field_name::ASCIIString, data::Pair{Float64,
     end
 end
 
-function update!(element::Element, field_name::ASCIIString, data::Pair{Float64, Vector{Vector{Float64}}})
+function update!(element::Element, field_name::String, data::Pair{Float64, Vector{Vector{Float64}}})
     if haskey(element, field_name)
         update!(element[field_name], data)
     else
@@ -185,7 +185,7 @@ function update!(element::Element, field_name::ASCIIString, data::Pair{Float64,
     end
 end
 
-function update!(element::Element, field_name::ASCIIString, data::Pair{Float64, Float64})
+function update!(element::Element, field_name::String, data::Pair{Float64, Float64})
     if haskey(element, field_name)
         update!(element[field_name], data)
     else
@@ -193,7 +193,7 @@ function update!(element::Element, field_name::ASCIIString, data::Pair{Float64,
     end
 end
 
-function update!(element::Element, field_name::ASCIIString, data::Union{Float64, Vector})
+function update!(element::Element, field_name::String, data::Union{Float64, Vector})
     if haskey(element, field_name)
         update!(element[field_name], data)
     else
@@ -215,15 +215,15 @@ function update!(element::Element, datas::Pair...)
     end
 end
 
-function update!(element::Element, field_name::ASCIIString, data::Function)
+function update!(element::Element, field_name::String, data::Function)
     element[field_name] = data
 end
 
-function update!(element::Element, field_name::ASCIIString, field::Field)
+function update!(element::Element, field_name::String, field::Field)
     element[field_name] = field
 end
 
-function update!(elements::Vector, field_name::ASCIIString, data)
+function update!(elements::Vector, field_name::String, data)
     for element in elements
         update!(element, field_name, data)
     end
@@ -290,7 +290,7 @@ end
 
 type Element{E}
     connectivity :: Vector{Int}
-    fields :: Dict{ASCIIString, Field}
+    fields :: Dict{String, Field}
     # matrices to construct dual basis
     D :: Matrix{Float64}
     M :: Matrix{Float64}
@@ -344,31 +344,31 @@ Examples
 >>> element["temperature"] = (0.0, [0, 0, 0, 0]), (1.0, [1, 2, 3, 4])
 >>> element["temperature"] = (0.0 => [0, 0, 0, 0], 1.0 => [1, 2, 3, 4])
 """
-function Base.setindex!(element::Element, data, name::ASCIIString)
+function Base.setindex!(element::Element, data, name::String)
     element.fields[name] = Field(data)
 end
-function Base.setindex!(element::Element, field::Field, name::ASCIIString)
+function Base.setindex!(element::Element, field::Field, name::String)
     element.fields[name] = field
 end
-function Base.setindex!(element::Element, data::Tuple, name::ASCIIString)
+function Base.setindex!(element::Element, data::Tuple, name::String)
     element.fields[name] = Field(data...)
 end
 
 
 typealias VecOrIP Union{Vector, IntegrationPoint}
 
-function call(element::Element, field_name::ASCIIString, time::Real, variation=nothing)
+function call(element::Element, field_name::String, time::Real, variation=nothing)
     return isa(variation, Void) ? element[field_name](time) : variation
 end
 
-function call(element::Element, field_name::ASCIIString, xi::VecOrIP, time::Number, variation=nothing)
+function call(element::Element, field_name::String, xi::VecOrIP, time::Number, variation=nothing)
     field = element(field_name, time, variation)
 #   field = isa(variation, Void) ? element[field_name](time) : variation
     basis = get_basis(element)
     return basis(field, xi)
 end
 
-function call(element::Element, field_name::ASCIIString, xi::VecOrIP, time::Number, ::Type{Val{:grad}}, variation=nothing)
+function call(element::Element, field_name::String, xi::VecOrIP, time::Number, ::Type{Val{:grad}}, variation=nothing)
 #   field = isa(variation, Void) ? element[field_name](time) : variation
     field = element(field_name, time, variation)
     basis = get_basis(element)
@@ -376,20 +376,20 @@ function call(element::Element, field_name::ASCIIString, xi::VecOrIP, time::Numb
     return basis(geom, field, xi, Val{:grad})
 end
 
-function call(element::Element, field_name::ASCIIString, xi::VecOrIP)
+function call(element::Element, field_name::String, xi::VecOrIP)
     field = element[field_name]
     basis = get_basis(element)
     return basis(element[field_name], xi)
 end
 
-function call(element::Element, field_name::ASCIIString, xi::VecOrIP, ::Type{Val{:grad}})
+function call(element::Element, field_name::String, xi::VecOrIP, ::Type{Val{:grad}})
     field = element[field_name]
     geom = element["geometry"]
     basis = get_basis(element)
     return basis(geom, field, xi, Val{:grad})
 end
 
-function call(element::Element, field_name::ASCIIString, time::Number)
+function call(element::Element, field_name::String, time::Number)
     return element[field_name](time)
 end
 
@@ -462,7 +462,7 @@ function call{E}(element::Element{E}, xi::VecOrIP, time::Float64, ::Type{Val{:gr
     return basis(element["geometry"](time), xi, Val{:grad})
 end
 
-function call(element::Element, field_name::ASCIIString)
+function call(element::Element, field_name::String)
     return element[field_name]
 end
 
@@ -630,7 +630,7 @@ end
 
 """ Update values for several elements at once. """
 # FIXME: with or without {T} ?
-function update!{T}(elements::Vector{Element{T}}, field_name::ASCIIString, data...)
+function update!{T}(elements::Vector{Element{T}}, field_name::String, data...)
     for element in elements
         update!(element, field_name, data...)
     end
diff --git a/src/fields.jl b/src/fields.jl
index 8c2409d..c36c5f7 100644
--- a/src/fields.jl
+++ b/src/fields.jl
@@ -15,7 +15,7 @@ type Field{A<:Union{Discrete,Continuous}, B<:Union{Constant,Variable}, C<:Union{
     data
 end
 
-typealias FieldSet Dict{ASCIIString, Field}
+typealias FieldSet Dict{String, Field}
 
 ### Basic data structure for discrete field
 
@@ -396,14 +396,14 @@ function call(basis::CVTI, geometry::DVTI, xi::Vector, ::Type{Val{:grad}})
 end
 
 function call(basis::CVTI, geometry::DVTI, values::DVTI, xi::Vector, ::Type{Val{:grad}})
-    grad = call(basis, geometry, xi, Val{:grad})
+    grad = basis(geometry, xi, Val{:grad})
 #    gradf = sum([grad[:,i]*values[i]' for i=1:length(geometry)])'
     gradf = sum([kron(grad[:,i], values[i]') for i=1:length(values)])'
     return length(gradf) == 1 ? gradf[1] : gradf
 end
 
 function call(basis::CVTI, xi::Vector, time::Number)
-    call(basis, xi)
+    basis(xi)
 end
 
 function Base.(:*)(grad::Matrix, field::DVTI)
diff --git a/src/interfaces.jl b/src/interfaces.jl
index 2491bb0..c9a71c1 100644
--- a/src/interfaces.jl
+++ b/src/interfaces.jl
@@ -8,7 +8,7 @@ using JuliaFEM.API: Model
 Function for creating solver and all the necessary components
 for the calculation
 """
-function get_solver(model::Model, case_name::ASCIIString)
+function get_solver(model::Model, case_name::String)
     case = model.load_cases[case_name]
     
     # Create core elements
@@ -118,7 +118,7 @@ end
 
 """
 """
-function solve!(model::Model, case_name::ASCIIString, time::Float64)
+function solve!(model::Model, case_name::String, time::Float64)
     # Create solver
 	solver = get_solver(model, case_name)
 
diff --git a/src/postprocess_xdmf.jl b/src/postprocess_xdmf.jl
index 8a6a09c..6122e70 100644
--- a/src/postprocess_xdmf.jl
+++ b/src/postprocess_xdmf.jl
@@ -100,7 +100,7 @@ function xdmf_new_result!(xdmf::XDMF, elements::Vector, time)
     set_attribute(dataitem, "DataType", "Float")
     set_attribute(dataitem, "Format", "XML")
     #set_attribute(dataitem, "Precision", 8)
-    s = ASCIIString[]
+    s = String[]
     ndim = 0
     for i in xdmf.permutation
         ndim += length(X[i])
@@ -117,7 +117,7 @@ function xdmf_new_result!(xdmf::XDMF, elements::Vector, time)
     set_attribute(dataitem, "Format", "XML")
     set_attribute(dataitem, "DataType", "Int")
 #   set_attribute(dataitem, "Precision", 8)
-    s = ASCIIString[]
+    s = String[]
     eldim = 0
     for element in elements
         eltype = get_xdmf_element_code(element)
@@ -167,7 +167,7 @@ function xdmf_save_field!(xdmf, elements::Vector, time, field_name; field_type="
     #set_attribute(dataitem, "Precision", 8)
     debug && info("field dim = $field_dim")
     debug && info(f)
-    s = ASCIIString[]
+    s = String[]
     dim = 0
     for i in xdmf.permutation
         gi = zeros(field_dim)
diff --git a/src/preprocess.jl b/src/preprocess.jl
index 0590567..2c19c79 100644
--- a/src/preprocess.jl
+++ b/src/preprocess.jl
@@ -18,10 +18,10 @@ using JuliaFEM
 
 type Mesh
     nodes :: Dict{Int64, Vector{Float64}}
-    node_sets :: Dict{ASCIIString, Set{Int64}}
+    node_sets :: Dict{String, Set{Int64}}
     elements :: Dict{Int64, Vector{Int64}}
     element_types :: Dict{Int64, Symbol}
-    element_sets :: Dict{ASCIIString, Set{Int64}}
+    element_sets :: Dict{String, Set{Int64}}
 end
 
 function Mesh()
@@ -38,7 +38,7 @@ function add_nodes!(mesh::Mesh, nodes::Dict{Int64, Vector{Float64}})
     end
 end
 
-function add_node_to_node_set!(mesh::Mesh, set_name::ASCIIString, nids...)
+function add_node_to_node_set!(mesh::Mesh, set_name::String, nids...)
     if !haskey(mesh.node_sets, set_name)
         mesh.node_sets[set_name] = Set{Int64}()
     end
@@ -56,7 +56,7 @@ function add_elements!(mesh::Mesh, elements::Dict{Int64, Tuple{Symbol, Vector{In
     end
 end
 
-function add_element_to_element_set!(mesh::Mesh, set_name::ASCIIString, elids...)
+function add_element_to_element_set!(mesh::Mesh, set_name::String, elids...)
     if !haskey(mesh.element_sets, set_name)
         mesh.element_sets[set_name] = Set{Int64}()
     end
@@ -84,7 +84,7 @@ function filter_by_element_id(mesh::Mesh, element_ids::Vector{Int64})
     return mesh2
 end
 
-function filter_by_element_set(mesh::Mesh, set_name::ASCIIString)
+function filter_by_element_set(mesh::Mesh, set_name::String)
     filter_by_element_id(mesh::Mesh, collect(mesh.element_sets[set_name]))
 end
 
@@ -99,7 +99,7 @@ function create_elements(mesh::Mesh)
     return elements
 end
 
-function create_elements(mesh::Mesh, element_sets::ASCIIString...)
+function create_elements(mesh::Mesh, element_sets::String...)
     elements = Element[]
     for element_set in element_sets
         new_elements = create_elements(filter_by_element_set(mesh, element_set))
diff --git a/src/preprocess_abaqus_reader.jl b/src/preprocess_abaqus_reader.jl
index 5dcb625..afcf265 100644
--- a/src/preprocess_abaqus_reader.jl
+++ b/src/preprocess_abaqus_reader.jl
@@ -81,7 +81,7 @@ Parse elements from input.
 function parse_section(model, lines, key, idx_start, idx_end, ::Type{Val{:ELEMENT}})
     definition = uppercase(lines[idx_start])
     element_type = regex_match(r"TYPE=([\w\-\_]+)", definition, 1)
-    eltype_sym = symbol(element_type)
+    eltype_sym = Symbol(element_type)
     eltype_nodes = element_has_nodes(Val{eltype_sym})
     element_type = element_has_type(Val{eltype_sym})
     info("Parsing elements. Type: $(element_type)")
@@ -195,13 +195,13 @@ function parse_abaqus(fid::IOStream)
     parser::Function = x->()
     model = Dict{AbstractString, Any}()
     model["nodes"] = Dict{Int64, Vector{Float64}}()
-    model["nsets"] = Dict{ASCIIString, Vector{Int64}}()
-    model["elsets"] = Dict{ASCIIString, Vector{Int64}}()
+    model["nsets"] = Dict{String, Vector{Int64}}()
+    model["elsets"] = Dict{String, Vector{Int64}}()
     model["elements"] = Dict{Integer, Any}()
     for idx_end in keyword_indexes[2:end]
         keyword_line = uppercase(lines[idx_start])
         keyword = regex_match(r"\s*(\w+)", keyword_line, 1)
-        k_sym = symbol(keyword)
+        k_sym = Symbol(keyword)
         if method_exists(parse_section, Tuple{Dict, Array{Integer, 1}, Symbol,
             Integer, Integer, Type{Val{k_sym}}})
             parse_section(model, lines, k_sym, idx_start, idx_end-1, Val{k_sym})
diff --git a/src/preprocess_abaqus_reader_old.jl b/src/preprocess_abaqus_reader_old.jl
index 4638b93..ff3b67b 100644
--- a/src/preprocess_abaqus_reader_old.jl
+++ b/src/preprocess_abaqus_reader_old.jl
@@ -100,7 +100,7 @@ function parse_abaqus(fid::IOStream)
     model = Dict()
     section = nothing
     header = nothing
-    data = ASCIIString[]
+    data = String[]
     info("Registered handlers: $(keys(handlers))")
 
     function process_section(section)
diff --git a/src/preprocess_aster_reader.jl b/src/preprocess_aster_reader.jl
index 92870d5..83a6bfd 100644
--- a/src/preprocess_aster_reader.jl
+++ b/src/preprocess_aster_reader.jl
@@ -39,7 +39,7 @@ function aster_create_elements(mesh, element_set, element_type=nothing; reverse_
 end
 
 
-function aster_parse_nodes(section::ASCIIString; strip_characters=true)
+function aster_parse_nodes(section::String; strip_characters=true)
     nodes = Dict{Any, Vector{Float64}}()
     has_started = false
     for line in split(section, '\n')
@@ -68,10 +68,10 @@ function aster_parse_nodes(section::ASCIIString; strip_characters=true)
     return nodes
 end
 
-function parse(mesh::ASCIIString, ::Type{Val{:CODE_ASTER_MAIL}})
-    model = Dict{ASCIIString, Any}()
+function parse(mesh::String, ::Type{Val{:CODE_ASTER_MAIL}})
+    model = Dict{String, Any}()
     header = nothing
-    data = ASCIIString[]
+    data = String[]
     for line in split(mesh, '\n')
         length(line) != 0 || continue
         info("line: $line")
@@ -242,7 +242,7 @@ type MEDFile
     data :: Dict
 end
 
-function MEDFile(fn::ASCIIString)
+function MEDFile(fn::String)
     MEDFile(h5read(fn, "/"))
 end
 
@@ -334,9 +334,9 @@ end
 
 Paramters
 ---------
-fn :: ASCIIString
+fn :: String
     file name to parse
-mesh_name :: ASCIIString, optional
+mesh_name :: String, optional
     mesh name, if several meshes in one file
 
 Returns
@@ -344,7 +344,7 @@ Returns
 Dict containing fields "nodes" and "connectivity".
 
 """
-function parse_aster_med_file(fn::ASCIIString, mesh_name=nothing; debug=false)
+function parse_aster_med_file(fn::String, mesh_name=nothing; debug=false)
     med = MEDFile(fn)
     if isa(mesh_name, Void)
         mesh_names = get_mesh_names(med::MEDFile)
@@ -362,7 +362,7 @@ function parse_aster_med_file(fn::ASCIIString, mesh_name=nothing; debug=false)
     end
     nodes = get_nodes(med, nsets, mesh_name)
     conn = get_connectivity(med, elsets, mesh_name)
-    result = Dict{ASCIIString, Any}()
+    result = Dict{String, Any}()
     result["nodes"] = nodes
     result["connectivity"] = conn
     return result
@@ -417,7 +417,7 @@ global const mapping = Dict(
 
     )
 
-function aster_read_mesh(fn::ASCIIString, mesh_name=nothing; reorder_element_connectivity=true)
+function aster_read_mesh(fn::String, mesh_name=nothing; reorder_element_connectivity=true)
     result = parse_aster_med_file(fn, mesh_name)
     mesh = Mesh()
     for (nid, (nset, ncoords)) in result["nodes"]
diff --git a/src/problems.jl b/src/problems.jl
index f0f0211..4c76620 100644
--- a/src/problems.jl
+++ b/src/problems.jl
@@ -84,9 +84,9 @@ function get_dofs(assembly::Assembly)
 end
 
 type Problem{P<:AbstractProblem}
-    name :: ASCIIString              # descriptive name for problem
+    name :: String              # descriptive name for problem
     dimension :: Int                 # degrees of freedom per node
-    parent_field_name :: ASCIIString # (optional) name of parent field e.g. "displacement"
+    parent_field_name :: String # (optional) name of parent field e.g. "displacement"
     elements :: Vector{Element}
     dofmap :: Dict{Element, Vector{Int64}} # connects element local dofs to global dofs
     assembly :: Assembly
@@ -103,7 +103,7 @@ julia> prob1 = Problem(Elasticity, "this is my problem", 3)
 julia> prob2 = Problem(Elasticity, 3)
 
 """
-function Problem{P<:FieldProblem}(::Type{P}, name::ASCIIString, dimension::Int64)
+function Problem{P<:FieldProblem}(::Type{P}, name::String, dimension::Int64)
     Problem{P}(name, dimension, "none", [], Dict(), Assembly(), P())
 end
 function Problem{P<:FieldProblem}(::Type{P}, dimension::Int64)
@@ -280,7 +280,7 @@ function length(problem::Problem)
     return length(problem.elements)
 end
 
-function update!(problem::Problem, field_name::ASCIIString, field)
+function update!(problem::Problem, field_name::String, field)
     update!(problem.elements, field_name, field)
 end
 
diff --git a/src/problems_contact.jl b/src/problems_contact.jl
index bdd3c4f..08d0fec 100644
--- a/src/problems_contact.jl
+++ b/src/problems_contact.jl
@@ -19,7 +19,7 @@ type Contact <: BoundaryProblem
     use_forwarddiff :: Bool
     minimum_active_set_size :: Int
     distval :: Float64
-    store_fields :: Vector{ASCIIString}
+    store_fields :: Vector{String}
 end
 
 function Contact()
diff --git a/src/problems_elasticity.jl b/src/problems_elasticity.jl
index dd7ec55..80c9dfb 100644
--- a/src/problems_elasticity.jl
+++ b/src/problems_elasticity.jl
@@ -38,7 +38,7 @@ type Elasticity <: FieldProblem
     formulation :: Symbol
     finite_strain :: Bool
     geometric_stiffness :: Bool
-    store_fields :: Vector{ASCIIString}
+    store_fields :: Vector{String}
 end
 function Elasticity()
     # formulations: plane_stress, plane_strain, continuum
diff --git a/src/problems_heat.jl b/src/problems_heat.jl
index fb64321..a03c838 100644
--- a/src/problems_heat.jl
+++ b/src/problems_heat.jl
@@ -44,8 +44,8 @@ https://en.wikipedia.org/wiki/Thermal_diffusivity
 https://en.wikipedia.org/wiki/Volumetric_heat_capacity
 """
 type Heat <: FieldProblem
-    formulation :: ASCIIString
-    store_fields :: Vector{ASCIIString}
+    formulation :: String
+    store_fields :: Vector{String}
 end
 
 function Heat()
diff --git a/src/problems_mortar.jl b/src/problems_mortar.jl
index 8722617..d4d2284 100644
--- a/src/problems_mortar.jl
+++ b/src/problems_mortar.jl
@@ -8,7 +8,7 @@ type Mortar <: BoundaryProblem
     dual_basis :: Bool
     use_forwarddiff :: Bool
     distval :: Float64
-    store_fields :: Vector{ASCIIString}
+    store_fields :: Vector{String}
 end
 
 function Mortar()
diff --git a/src/solvers.jl b/src/solvers.jl
index 7ecd03c..c69bf09 100644
--- a/src/solvers.jl
+++ b/src/solvers.jl
@@ -4,7 +4,7 @@
 abstract AbstractSolver
 
 type Solver{S<:AbstractSolver}
-    name :: ASCIIString # some descriptive name for problem
+    name :: String # some descriptive name for problem
     time :: Real        # current time
     problems :: Vector{Problem}
     norms :: Vector{Tuple}  # solution norms for convergence studies
@@ -27,7 +27,7 @@ function push!(solver::Solver, problem)
     push!(solver.problems, problem)
 end
 
-function getindex(solver::Solver, problem_name::ASCIIString)
+function getindex(solver::Solver, problem_name::String)
     for problem in get_problems(solver)
         if problem.name == problem_name
             return problem
@@ -461,7 +461,7 @@ function NonlinearSolver(problems...)
     end
     return solver
 end
-function NonlinearSolver(name::ASCIIString, problems::Problem...)
+function NonlinearSolver(name::String, problems::Problem...)
     solver = NonlinearSolver(problems...)
     solver.name = name
     return solver
@@ -526,7 +526,7 @@ function LinearSolver(problems::Problem...)
     end
     return solver
 end
-function LinearSolver(name::ASCIIString, problems::Problem...)
+function LinearSolver(name::String, problems::Problem...)
     solver = LinearSolver(problems...)
     solver.name = name
     return solver
@@ -591,7 +591,7 @@ function Postprocessor(problems::Problem...)
     return solver
 end
 
-function Postprocessor(name::ASCIIString, problems::Problem...)
+function Postprocessor(name::String, problems::Problem...)
     solver = Postprocessor(problems...)
     solver.name = name
     return solver
diff --git a/src/solvers_modal.jl b/src/solvers_modal.jl
index 176cdb9..89d2024 100644
--- a/src/solvers_modal.jl
+++ b/src/solvers_modal.jl
@@ -8,7 +8,7 @@ Examples
 julia> problems = get_problems()
 julia> solver = Solver(Modal)
 julia> push!(solver, problems...)
-julia> call(solver)
+julia> solver()
 
 """
 type Modal <: AbstractSolver
diff --git a/src/types.jl b/src/types.jl
index 658dc8d..598405e 100644
--- a/src/types.jl
+++ b/src/types.jl
@@ -9,15 +9,15 @@ type Point{P<:AbstractPoint}
     id :: Int
     weight :: Float64
     coords :: Vector{Float64}
-    fields :: Dict{ASCIIString, Field}
+    fields :: Dict{String, Field}
     properties :: P
 end
 
-function setindex!{T}(point::Point, val::Pair{Float64, T}, field_name::ASCIIString)
+function setindex!{T}(point::Point, val::Pair{Float64, T}, field_name::String)
     point.fields[field_name] = Field(val)
 end
 
-function getindex(point::Point, field_name::ASCIIString)
+function getindex(point::Point, field_name::String)
     return point.fields[field_name]
 end
 
@@ -25,11 +25,11 @@ function getindex(point::Point, idx::Int)
     return point.coords[idx]
 end
 
-function haskey(point::Point, field_name::ASCIIString)
+function haskey(point::Point, field_name::String)
     return haskey(point.fields, field_name)
 end
 
-function call(point::Point, field_name::ASCIIString, time::Float64=0.0)
+function call(point::Point, field_name::String, time::Float64=0.0)
     point.fields[field_name](time).data
 end
 
diff --git a/test/test_contact_2d_small_sliding.jl b/test/test_contact_2d_small_sliding.jl
index 4d8ae33..9495fcd 100644
--- a/test/test_contact_2d_small_sliding.jl
+++ b/test/test_contact_2d_small_sliding.jl
@@ -55,7 +55,7 @@ end
 @testset "test all nodes in contact" begin
     # FIXME: needs verification of some other fem software
     solver = get_model("curved 2d contact small sliding")
-    call(solver)
+    solver()
     upper, lower, bc_upper, bc_lower, interface = solver.problems
     @test isapprox(norm(interface.assembly.u), 0.49563347601324315)
 end
@@ -119,7 +119,7 @@ end
 
 @testset "test frictionless hertz contact, 2d plane strain" begin
     solver = get_model("hertz contact, full 2d model")
-    call(solver)
+    solver()
     upper, lower, bc_fixed, bc_sym_23, load, contact = solver.problems
     slaves = get_slave_elements(contact)
     node_ids, la = get_nodal_vector(slaves, "reaction force", 0.0)
diff --git a/test/test_contact_3d_small_sliding.jl b/test/test_contact_3d_small_sliding.jl
index 54997fd..c1413fa 100644
--- a/test/test_contact_3d_small_sliding.jl
+++ b/test/test_contact_3d_small_sliding.jl
@@ -45,7 +45,7 @@ using JuliaFEM.Test
     solver = Solver(Nonlinear)
     push!(solver, upper, lower, bc_upper, bc_lower, contact)
 
-    call(solver)
+    solver()
     for element in get_slave_elements(contact)
         normal = element("normal", [1/3, 1/3], solver.time)
         @test isapprox(normal, [0.0, 0.0, 1.0])
diff --git a/test/test_dirichlet.jl b/test/test_dirichlet.jl
index 900ffc8..fc75ad0 100644
--- a/test/test_dirichlet.jl
+++ b/test/test_dirichlet.jl
@@ -122,7 +122,7 @@ end
     update!(element, "geometry", X)
     update!(element, "displacement 1", 0.0)
     f(xi, time) = begin
-        info("function call at xi = $xi, time = $time")
+        info("function called at xi = $xi, time = $time")
         X = element("geometry", xi, time)
         info("geometry at xi, X = $X")
         val = X[1]*time
diff --git a/test/test_elasticity_2d_linear_with_surface_load.jl b/test/test_elasticity_2d_linear_with_surface_load.jl
index 6b40d09..78b2b93 100644
--- a/test/test_elasticity_2d_linear_with_surface_load.jl
+++ b/test/test_elasticity_2d_linear_with_surface_load.jl
@@ -44,7 +44,7 @@ end
 
     solver = get_model("test 2d linear elasticity with surface + volume load")
     block, bc_sym = solver.problems
-    call(solver)
+    solver()
 
     f = 288.0
     g = 576.0
@@ -86,7 +86,7 @@ end
     solver = get_model("test 2d linear elasticity with surface + volume load")
     save("/tmp/model.jld", "linear_model", solver)
     solver2 = load("/tmp/model.jld")["linear_model"]
-    call(solver2)
+    solver2()
     save("/tmp/model.jld", "results", solver2)
     solver3 = load("/tmp/model.jld")["results"]
     block = solver3["BLOCK"]
diff --git a/test/test_elasticity_2d_nonhomogeneous_boundary_conditions.jl b/test/test_elasticity_2d_nonhomogeneous_boundary_conditions.jl
index cbb01d5..9e3a5bb 100644
--- a/test/test_elasticity_2d_nonhomogeneous_boundary_conditions.jl
+++ b/test/test_elasticity_2d_nonhomogeneous_boundary_conditions.jl
@@ -38,7 +38,7 @@ using JuliaFEM.Test
 
     solver = NonlinearSolver("solve block problem")
     push!(solver, block, bc)
-    call(solver)
+    solver()
 
     # from code aster
     eps_expected = [-2.08333312468287E-01, 6.25000000000000E-01, 0.0]
diff --git a/test/test_elasticity_2d_nonlinear_with_surface_load.jl b/test/test_elasticity_2d_nonlinear_with_surface_load.jl
index fb07f32..6fac4b1 100644
--- a/test/test_elasticity_2d_nonlinear_with_surface_load.jl
+++ b/test/test_elasticity_2d_nonlinear_with_surface_load.jl
@@ -34,7 +34,7 @@ using JuliaFEM.Test
 
     solver = NonlinearSolver("solve block problem")
     push!(solver, block, bc_sym)
-    call(solver)
+    solver()
 
     # from code aster
     u3_expected = [-4.92316106779943E-01, 7.96321884292103E-01]
diff --git a/test/test_elasticity_3d_linear_with_surface_load.jl b/test/test_elasticity_3d_linear_with_surface_load.jl
index b811d59..f4d9cce 100644
--- a/test/test_elasticity_3d_linear_with_surface_load.jl
+++ b/test/test_elasticity_3d_linear_with_surface_load.jl
@@ -40,7 +40,7 @@ using JuliaFEM.Test
     push!(boundary_problem, symxy, symxz, symyz)
 
     solver = LinearSolver(elasticity_problem, boundary_problem)
-    call(solver)
+    solver()
 
     disp = element1("displacement", [1.0, 1.0, 1.0], 0.0)
     info("displacement at tip: $disp")
@@ -70,7 +70,7 @@ function solve_rod_model_elasticity(eltype)
     update!(p4, "displacement 2", 0.0)
     update!(p5, "displacement 3", 0.0)
     solver = LinearSolver(p1, p2, p3, p4, p5)
-    call(solver)
+    solver()
     u_max = maximum(p1.assembly.u)
     info("$eltype, u_max = $u_max")
     return u_max
diff --git a/test/test_elasticity_3d_nonlinear_with_surface_load.jl b/test/test_elasticity_3d_nonlinear_with_surface_load.jl
index fcf8ba2..3d12560 100644
--- a/test/test_elasticity_3d_nonlinear_with_surface_load.jl
+++ b/test/test_elasticity_3d_nonlinear_with_surface_load.jl
@@ -41,7 +41,7 @@ using JuliaFEM.Test
     solver = NonlinearSolver("solve 3d block")
     push!(solver, elasticity_problem)
     push!(solver, boundary_problem)
-    call(solver)
+    solver()
 
     disp = element1("displacement", [1.0, 1.0, 1.0], 0.0)
     info("displacement at tip: $disp")
diff --git a/test/test_elasticity_3d_unit_block.jl b/test/test_elasticity_3d_unit_block.jl
index 5cd1b6d..b878971 100644
--- a/test/test_elasticity_3d_unit_block.jl
+++ b/test/test_elasticity_3d_unit_block.jl
@@ -35,7 +35,7 @@ function calc_model(mesh_name; with_volume_load=false, debug_print=false)
 
     solver = LinearSolver("Solver block problem")
     push!(solver, block, traction, bc)
-    call(solver)
+    solver()
 
     max_u = maximum(block.assembly.u)
     nu = round(Int, length(block.assembly.u)/3)
diff --git a/test/test_elasticity_forwarddiff.jl b/test/test_elasticity_forwarddiff.jl
index a1b54a1..d3803ac 100644
--- a/test/test_elasticity_forwarddiff.jl
+++ b/test/test_elasticity_forwarddiff.jl
@@ -41,7 +41,7 @@ using JuliaFEM.Test
 
     solver = Solver()
     push!(solver, body, bc)
-    call(solver)
+    solver()
     disp = element("displacement", [1.0, 1.0], 0.0)
     info("displacement at tip: $disp")
     # verified using Code Aster, verification/2015-10-22-plane-stress/cplan_grot_gdep_volume_force.resu
diff --git a/test/test_elasticity_tetra.jl b/test/test_elasticity_tetra.jl
index 419bc2f..70ebfe6 100644
--- a/test/test_elasticity_tetra.jl
+++ b/test/test_elasticity_tetra.jl
@@ -26,7 +26,7 @@ using JuliaFEM.Test
     push!(p2, e2)
     s = Solver(Linear)
     push!(s, p1, p2)
-    call(s)
+    s()
     u_4 = p1.assembly.u[10:end]
     u_expected = [-3.0/220.0, -9.0/220.0, 1.0/10.0]
     @test isapprox(u_4, u_expected)
@@ -56,7 +56,7 @@ end
     push!(p2, e2)
     s = Solver(Linear)
     push!(s, p1, p2)
-    call(s)
+    s()
     u_4 = p1.assembly.u[10:end]
     u_expected = [-17.0/14.0, -27.0/14.0, 1.0]
     info("u_4 = $(u_4)")
diff --git a/test/test_heat.jl b/test/test_heat.jl
index 62709f2..d3bae0c 100644
--- a/test/test_heat.jl
+++ b/test/test_heat.jl
@@ -22,7 +22,7 @@ using JuliaFEM.Postprocess
     info("# of elements in fixed set: $(length(fixed))")
     update!(fixed, "temperature 1", 0.0)
     solver = LinearSolver(prob, face, fixed)
-    call(solver)
+    solver()
     T = prob.assembly.u
     info("Solution: $T")
     T_expected = [ # using code aster
@@ -94,7 +94,7 @@ end
     # T=1 on free boundary, u(x,y) = -1/6*(1/2*f*x^2 - f*x)
     # when boundary flux not active (at t=0)
     solver.time = 0.0
-    call(solver)
+    solver()
     # interpolate temperature at middle of element 2 (flux boundary) at time t=0:
     T = el2("temperature", [0.0], 0.0)
     @test isapprox(T[1], 1.0)
@@ -103,7 +103,7 @@ end
     # u(x,y) = x which equals T=1 on boundary.
     # at time t=1.0 all loads should be on.
     solver.time = 1.0
-    call(solver)
+    solver()
     T = el2("temperature", [0.0], 1.0)
     @test isapprox(T[1], 2.0)
 end
@@ -152,7 +152,7 @@ end
     push!(p2, e3)
 
     solver = LinearSolver(p1, p2)
-    call(solver)
+    solver()
     T_min = minimum(p1.assembly.u)
     @test isapprox(T_max, T_acc(0.2); rtol=4.5e-2)
 end
@@ -189,7 +189,7 @@ end
     update!(p2, "temperature 1", 100.0)
 
     solver = LinearSolver(p1, p2)
-    call(solver)
+    solver()
 
     # fields extracted from Code Aster .resu file
     TEMP = Dict{Int64, Float64}(
@@ -221,7 +221,7 @@ end
         8 => [1.74447696000717E+04, -4.72904678032179E+02, -1.75280965396335E+02])
 
     postprocessor = Postprocessor(p1)
-    flux = full(call(postprocessor))
+    flux = full(postprocessor())
     fluxd = Dict{Int64, Vector{Float64}}()
     for j=1:8
         fluxd[j] = vec(flux[j,:])
@@ -269,7 +269,7 @@ end
         update!(p1, "temperature heat transfer coefficient", 1000.0)
         update!(p2, "temperature 1", 100.0)
         solver = LinearSolver(p1, p2)
-        call(solver)
+        solver()
         T_min = minimum(p1.assembly.u)
         return T_min
     end
@@ -317,7 +317,7 @@ end
         p2.elements = create_elements(mesh, "FACE1")
         update!(p2, "temperature 1", 100.0)
         solver = LinearSolver(p1, p2)
-        call(solver)
+        solver()
         return p1.assembly.u
     end
 
diff --git a/test/test_modal_analysis.jl b/test/test_modal_analysis.jl
index f526940..bc3f56d 100644
--- a/test/test_modal_analysis.jl
+++ b/test/test_modal_analysis.jl
@@ -35,7 +35,7 @@ using JuliaFEM.Test
     s1.properties.which = :LM
     push!(s1, p1, p2)
 
-    call(s1; debug=true)
+    s1(; debug=true)
     @test isapprox(s1.properties.eigvals, [4/3, 1/3])
 
     empty!(p1)
@@ -44,7 +44,7 @@ using JuliaFEM.Test
 #   p1.properties.finite_strain = true
     p1.properties.geometric_stiffness = true
     s1.properties.geometric_stiffness = true
-    call(s1; debug=true)
+    s1(; debug=true)
     @test isapprox(s1.properties.eigvals, [5/3, 2/3])
 end
 
@@ -80,7 +80,7 @@ end
 
     solver = Solver(Modal)
     push!(solver, p1, p2)
-    call(solver)
+    solver()
     @test isapprox(solver.properties.eigvals[1], 1.0)
 end
 
@@ -124,7 +124,7 @@ end
     push!(p4, el5, el6)
     solver = Solver(Modal)
     push!(solver, p1, p2, p3, p4)
-    call(solver)
+    solver()
     @test isapprox(solver.properties.eigvals[1], 1.0)
 end
 
diff --git a/test/test_mortar.jl b/test/test_mortar.jl
index de2134f..30ad75d 100644
--- a/test/test_mortar.jl
+++ b/test/test_mortar.jl
@@ -372,7 +372,7 @@ function test_3d_problem()
     push!(solver, tie)
     solver.nonlinear_problem = false
     solver.method = :UMFPACK
-    call(solver, 0.0)
+    solver()
     X = el2("geometry", [1.0, 1.0, 1.0], 0.0)
     u = el2("displacement", [1.0, 1.0, 1.0], 0.0)
     info("displacement at $X = $u")
diff --git a/test/test_mortar_2d_assembly.jl b/test/test_mortar_2d_assembly.jl
index f635bbc..e379223 100644
--- a/test/test_mortar_2d_assembly.jl
+++ b/test/test_mortar_2d_assembly.jl
@@ -100,7 +100,7 @@ end
     push!(bc3, sel1, mel1)
 
     solver = LinearSolver(body1, body2, bc1, bc2, bc3)
-    call(solver)
+    solver()
 
     u = e2("displacement", [1.0, 1.0], 0.0)
     u_expected = [-1/3, 1.0]
diff --git a/test/test_mortar_2d_contact.jl b/test/test_mortar_2d_contact.jl
index 4cf86f3..db4fb83 100644
--- a/test/test_mortar_2d_contact.jl
+++ b/test/test_mortar_2d_contact.jl
@@ -73,7 +73,7 @@ end
 
 @testset "test simple two element contact" begin
     solver = get_model("two element contact")
-    call(solver)
+    solver()
     contact = solver["LOWER_TO_UPPER"]
     master = first(contact.elements)
     slave = last(contact.elements)
diff --git a/test/test_mortar_2d_mesh_tie.jl b/test/test_mortar_2d_mesh_tie.jl
index 0a16566..807e376 100644
--- a/test/test_mortar_2d_mesh_tie.jl
+++ b/test/test_mortar_2d_mesh_tie.jl
@@ -49,7 +49,7 @@ end
     p4.properties.rotate_normals = false
     solver = Solver(Linear)
     push!(solver, p1, p2, p3, p4)
-    call(solver)
+    solver()
     el5 = p4.elements[1]
     u = el5("displacement", [0.0], 0.0)
     info("u = $u")
@@ -86,7 +86,7 @@ end
 
     solver = Solver(Linear)
     push!(solver, upper, lower, bc_upper, bc_lower, interface)
-    call(solver)
+    solver()
 
     interface_norm = norm(interface.assembly)
     # for bi-orthogonal:
@@ -123,7 +123,7 @@ end
     solver = Solver(Nonlinear)
     solver.properties.linear_system_solver = :DirectLinearSolver_UMFPACK
     push!(solver, p1, p2, p3, p4)
-    call(solver)
+    solver()
     el5 = p4.elements[1]
     u = el5("displacement", [0.0], 0.0)
     info("u = $u")
@@ -183,7 +183,7 @@ end
 @testset "test mesh tie with splitted block and plane stress elasticity" begin
     solver = get_model("splitted block, plane stress elasticity and mesh tie")
     upper, lower, bc_upper, bc_lower, interface = solver.problems
-    call(solver)
+    solver()
     slave_elements = get_slave_elements(interface)
     node_ids, la = get_nodal_vector(slave_elements, "reaction force", 0.0)
     for lai in la
@@ -250,7 +250,7 @@ end
     solver = get_model("mesh tie with curved 2d block";
         adjust=true, tolerance=10, dy=0.0, rotate_normals=true,
         dual_basis=false)
-    call(solver)
+    solver()
     interface = solver["interface between upper and lower block"]
     @test isapprox(norm(interface.assembly.u), 0.11339715157447851)
 end
@@ -260,7 +260,7 @@ end
     solver = get_model("mesh tie with curved 2d block";
         adjust=true, tolerance=10, dy=0.0, rotate_normals=true,
         dual_basis=true)
-    call(solver)
+    solver()
     interface = solver["interface between upper and lower block"]
     @test isapprox(norm(interface.assembly.u), 0.11660422877751599)
 end
@@ -270,7 +270,7 @@ end
     solver = get_model("mesh tie with curved 2d block";
         adjust=true, tolerance=10, dy=-0.1, rotate_normals=true,
         dual_basis=false)
-    call(solver)
+    solver()
     interface = solver["interface between upper and lower block"]
     @test isapprox(norm(interface.assembly.u), 0.34230262165505887)
 end
@@ -280,7 +280,7 @@ end
     solver = get_model("mesh tie with curved 2d block";
         adjust=true, tolerance=10, dy=-0.1, rotate_normals=true,
         dual_basis=true)
-    call(solver)
+    solver()
     interface = solver["interface between upper and lower block"]
     @test isapprox(norm(interface.assembly.u), 0.34318800698017704)
 end
diff --git a/test/test_mortar_2d_mesh_tie_forwarddiff.jl b/test/test_mortar_2d_mesh_tie_forwarddiff.jl
index fd907be..b40ac38 100644
--- a/test/test_mortar_2d_mesh_tie_forwarddiff.jl
+++ b/test/test_mortar_2d_mesh_tie_forwarddiff.jl
@@ -75,7 +75,7 @@ end
         adjust=false, tolerance=10, dy=-0.1, rotate_normals=true,
         dual_basis=true, use_forwarddiff=true, finite_strain=false,
         geometric_stiffness=false)
-    call(solver)
+    solver()
     interface = solver["interface between upper and lower block"]
     @test isapprox(norm(interface.assembly.u), 0.11339715157447851)
 end
@@ -86,7 +86,7 @@ end
     solver = get_model("mesh tie with curved 2d block";
         adjust=true, tolerance=10, dy=0.0, rotate_normals=true,
         dual_basis=true, use_forwarddiff=true)
-    call(solver)
+    solver()
     interface = solver["interface between upper and lower block"]
     @test solver.properties.iteration == 2
     # differs -- why?
@@ -98,7 +98,7 @@ end
     solver = get_model("mesh tie with curved 2d block";
         adjust=true, tolerance=10, dy=-0.1, rotate_normals=true,
         dual_basis=false, use_forwarddiff=true)
-    call(solver)
+    solver()
     interface = solver["interface between upper and lower block"]
     @test solver.properties.iteration == 2
     @test isapprox(norm(interface.assembly.u), 0.34230262165505887)
@@ -109,7 +109,7 @@ end
     solver = get_model("mesh tie with curved 2d block";
         adjust=true, tolerance=10, dy=-0.1, rotate_normals=true,
         dual_basis=true, use_forwarddiff=true)
-    call(solver)
+    solver()
     interface = solver["interface between upper and lower block"]
     @test solver.properties.iteration == 2
     @test isapprox(norm(interface.assembly.u), 0.34318800698017704)
diff --git a/test/test_mortar_3d_mesh_tie.jl b/test/test_mortar_3d_mesh_tie.jl
index 9f26507..bf2f47f 100644
--- a/test/test_mortar_3d_mesh_tie.jl
+++ b/test/test_mortar_3d_mesh_tie.jl
@@ -32,7 +32,7 @@ using JuliaFEM.Test
     interface.elements = [interface_master_elements; interface_slave_elements]
 
     solver = LinearSolver(upper, lower, bc_upper, bc_lower, interface)
-    call(solver)
+    solver()
     
     node_ids, temperature = get_nodal_vector(interface.elements, "temperature", 0.0)
     T = [t[1] for t in temperature]
diff --git a/test/test_nodal_constraints.jl b/test/test_nodal_constraints.jl
index f9c502c..b4c4ef4 100644
--- a/test/test_nodal_constraints.jl
+++ b/test/test_nodal_constraints.jl
@@ -54,7 +54,7 @@ end
     update!(nodal_bc, "displacement 1", 0.5)
     update!(nodal_bc, "displacement 2", 0.0)
     push!(solver, nodal_bc)
-    call(solver)
+    solver()
     pel = nodal_bc.elements[1]
     la = pel("reaction force", [0.0], 0.0)
     info("reaction force: $la")
@@ -76,7 +76,7 @@ end
     update!(point_load, "displacement traction force 1", 72.0)
     update!(point_load, "displacement traction force 2", 27.0)
     push!(solver["body"], point_load)
-    call(solver)
+    solver()
     @test isapprox(point_load("displacement", [], 0.0), [0.5, 0.0])
 end
 
diff --git a/test/test_preprocess_aster_reader.jl b/test/test_preprocess_aster_reader.jl
index c106ed4..9e23e2d 100644
--- a/test/test_preprocess_aster_reader.jl
+++ b/test/test_preprocess_aster_reader.jl
@@ -66,7 +66,7 @@ end
 
 @testset "test combining meshes" begin
 
-    mesh1 = Dict{ASCIIString, Any}(
+    mesh1 = Dict{String, Any}(
         "nodes" => Dict{Int64, Vector{Float64}}(
             1 => [1.0, 2.0],
             2 => [2.0, 3.0]
@@ -76,7 +76,7 @@ end
         ),
     )
 
-    mesh2 = Dict{ASCIIString, Any}(
+    mesh2 = Dict{String, Any}(
         "nodes" => Dict{Int64, Vector{Float64}}(
             1 => [3.0, 4.0],
             2 => [4.0, 5.0]