extend alchemist for particulate matter concentration

lib/alchemist.rb

@@ -24,6 +24,7 @@ class << self
   @@si_units += %w[ampere]
   @@si_units += %w[metre_per_second metre_per_second_squared]
   @@si_units += %w[unitless]
+  @@si_units += %w[pieces_per_cubic_metre]
 
   @@common_metric_units = {
     :dimensionless => :unitless,
@@ -38,7 +39,8 @@ class << self
     :pressure => :pascal,
     :distance => :meter,
 		:velocity => :metre_per_second,
-		:acceleration => :metre_per_second_squared
+		:acceleration => :metre_per_second_squared,
+    :particulate_matter_concentration => :pieces_per_cubic_metre
   }
   @@common_imperial_units = {
     :dimensionless => :unitless,
@@ -53,7 +55,8 @@ class << self
     :pressure => :psi,
     :distance => :feet,
 		:velocity => :metre_per_second,
-		:acceleration => :metre_per_second_squared
+		:acceleration => :metre_per_second_squared,
+    :particulate_matter_concentration => :pieces_per_cubic_foot
   }
 
   @@operator_actions = {}
@@ -265,6 +268,10 @@ class << self
       #unusual measurements
       :elephant => 5443108.44, :elephants => 5443108.44
     },
+    :particulate_matter_concentration => {
+      :pieces_per_cubic_metre => 1.0,
+      :pieces_per_cubic_foot => 35.314667
+    },
     :power => {
       :watt => 1.0, :watts => 1.0, :W => 1.0,
       :british_thermal_unit_per_hour => 2.928751e-1, :british_thermal_units_per_hour => 2.928751e-1,

locales/de.yml

@@ -157,3 +157,14 @@ de:
           one: "Umdrehung pro Minute"
           many: "Umdrehungen pro Minute"
         symbol: "RPM"
+    particulate_matter_concentration:
+      pieces_per_cubic_metre:
+        name:
+          one: "Partikel pro Kubikmeter"
+          many: "Partikel pro Kubikmeter"
+        symbol: "part./m³"
+      pieces_per_cubic_foot:
+        name:
+          one: "Partikel pro Kubikfuss"
+          many: "Partikel pro Kubikfuss"
+        symbol: "part./cft"

locales/en.yml

@@ -163,3 +163,14 @@ en:
           one: "Revolution per minute"
           many: "Revolutions per minute"
         symbol: "RPM"
+    particulate_matter_concentration:
+      pieces_per_cubic_metre:
+        name:
+          one: "piece per cubic metre"
+          many: "pieces per cubic metre"
+        symbol: "pcs/m³"
+      pieces_per_cubic_foot:
+        name:
+          one: "piece per cubic foot"
+          many: "pieces per cubic foot"
+        symbol: "pcs/cft"

test/alchemist_test.rb

@@ -244,5 +244,18 @@ def test_standard_gravity
     assert 1.standard_gravity.unit_symbol_t.to_s == "g"
 	end
 
+  def test_particulate_matter_concentration
+		assert_in_delta(1.pieces_per_cubic_metre.to.pieces_per_cubic_foot.to_f, 0.0283168, 1e-5)
+		assert_in_delta(1.pieces_per_cubic_foot.to.pieces_per_cubic_metre.to_f, 35.3146667, 1e-5)
+    I18n.locale = "en"
+    assert 1.pieces_per_cubic_metre.unit_name_t.to_s == "piece per cubic metre"
+    assert 2.pieces_per_cubic_metre.unit_name_t.to_s == "pieces per cubic metre"
+    assert 1.pieces_per_cubic_metre.unit_symbol_t.to_s == "pcs/m³"
+    I18n.locale = "de"
+    assert 1.pieces_per_cubic_metre.unit_name_t.to_s == "Partikel pro Kubikmeter"
+    assert 2.pieces_per_cubic_metre.unit_name_t.to_s == "Partikel pro Kubikmeter"
+    assert 1.pieces_per_cubic_metre.unit_symbol_t.to_s == "part./m³"
+  end
+
 end