fix/update Marangoni coefficients in Mist files

src/myna/mist_material_data/IN625.json

@@ -57,7 +57,7 @@
         },
         "marangoni_coefficient": {
             "print_name": "Marangoni coefficient",
-            "value": 2.0e-5,
+            "value": -2.0e-5,
             "unit": "N/(m~K)",
             "reference": "Z. Gan, Y. Lian, S.E. Lin, K.K. Jones, W.K. Liu, G.J. Wagner, Benchmark Study of Thermal Behavior, Surface Topography, and Dendritic Microstructure in Selective Laser Melting of Inconel 625, Integrating Materials and Manufacturing Innovation 8(2) (2019) 178-193.",
             "uncertainty": "None",
@@ -136,5 +136,5 @@
             "print_symbol": "\\alpha"
         }
     },
-    "note": "None."
+    "note": "- The Marangoni coefficient in Gan et al. (2019) is based on fitting of a thermofluidic model to experimental data, not direct measurement"
 }

src/myna/mist_material_data/IN718.json

@@ -57,7 +57,7 @@
         },
         "marangoni_coefficient": {
             "print_name": "Marangoni coefficient",
-            "value": 2.0e-5,
+            "value": -2.0e-5,
             "unit": "N/(m~K)",
             "reference": "Z. Gan, Y. Lian, S.E. Lin, K.K. Jones, W.K. Liu, G.J. Wagner, Benchmark Study of Thermal Behavior, Surface Topography, and Dendritic Microstructure in Selective Laser Melting of Inconel 625, Integrating Materials and Manufacturing Innovation 8(2) (2019) 178-193.",
             "uncertainty": "None",
@@ -136,5 +136,5 @@
             "print_symbol": "\\alpha"
         }
     },
-    "note": "All temperature-dependent expressions use units of K. The dynamic viscosity and Marangoni coefficent values are from IN625 references. The latent heat of vaporization and molecular mass are taken from pure nickel references. The emissivity is an estimate of total hemispherical emissivity on a smooth surface. Actual emissivity depends on the surface condition."
+    "note": "- The Marangoni coefficient in Gan et al. (2019) is based on fitting of a thermofluidic model to experimental data, not direct measurement\n- All temperature-dependent expressions use units of K\n- The dynamic viscosity and Marangoni coefficent values are from IN625 references\n- The latent heat of vaporization and molecular mass are taken from pure nickel references\n- The emissivity is an estimate of total hemispherical emissivity on a smooth surface--actual emissivity depends on the surface condition"
 }

src/myna/mist_material_data/SS316H.json

@@ -129,7 +129,15 @@
             "reference": "None",
             "uncertainty": "None",
             "print_symbol": "\\alpha"
+        },
+        "marangoni_coefficient": {
+            "print_name": "Marangoni coefficient",
+            "value": -4.0e-4,
+            "unit": "N/(m~K)",
+            "reference": "K.C. Mills, Y. Su, Z. Li, R.F. Brooks, Equations for the calculation of the thermo-physical properties of stainless steel, ISIJ international 44(10) (2004) 1661-1668. DOI:  https://doi.org/10.2355/isijinternational.44.1661.",
+            "uncertainty": "None",
+            "print_symbol": "\frac{\\partial \\gamma}{\\partial T}"
         }
     },
-    "note": "This file currently excludes the surface tension, marangoni coefficient, and the vapor pressure due to the need for function representations other than Laurent polynomials."
+    "note": "- The Marangoni coefficient in Mills et al. (2004) is evaluated at 1925 K and 0 ppm S\n- This file currently excludes the the vapor pressure due to the need for function representations other than Laurent polynomials."
 }

src/myna/mist_material_data/SS316L.json

@@ -129,7 +129,15 @@
             "reference": "None",
             "uncertainty": "None",
             "print_symbol": "\\alpha"
+        },
+        "marangoni_coefficient": {
+            "print_name": "Marangoni coefficient",
+            "value": -4.0e-4,
+            "unit": "N/(m~K)",
+            "reference": "K.C. Mills, Y. Su, Z. Li, R.F. Brooks, Equations for the calculation of the thermo-physical properties of stainless steel, ISIJ international 44(10) (2004) 1661-1668. DOI:  https://doi.org/10.2355/isijinternational.44.1661.",
+            "uncertainty": "None",
+            "print_symbol": "\frac{\\partial \\gamma}{\\partial T}"
         }
     },
-    "note": "This file currently excludes the surface tension, marangoni coefficient, and the vapor pressure due to the need for function representations other than Laurent polynomials."
+    "note": "- The Marangoni coefficient in Mills et al. (2004) is evaluated at 1925 K and 0 ppm S\n- This file currently excludes the the vapor pressure due to the need for function representations other than Laurent polynomials."
 }