Arthur Henn - Academia.edu (original) (raw)

Papers by Arthur Henn

International Symposium on Electromagnetic Compatibility, 1992

ABSTRACT

in the group of Professor Alan G. MacDiarmid, who was awarded the Nobel Prize in chemistry in 200... more in the group of Professor Alan G. MacDiarmid, who was awarded the Nobel Prize in chemistry in 2000 for co-discovery of CP's. There, Dr. Avloni worked (1991-1995) on synthesis, characterization, blending and processing of CP materials. He was the first to demonstrate the effect of CP molecular conformation on their electrical conductivity. Dr. Arthur Henn, Pres. of Marktek Inc., has been involved with conductive textiles for 18 years. Prior to founding Marktek Inc. in 1994, he was one of the key team leaders in the technical and commercial development of Flectron® metalized materials at Monsanto Co.

The Journal of Physical Chemistry, 1989

we derive A.So1200 = 171.1 f 3 J K-I mol-' for reaction 1 using the second-law method; when combi... more we derive A.So1200 = 171.1 f 3 J K-I mol-' for reaction 1 using the second-law method; when combined with entropy data for ThF4(g), and Th02(s),'0 this leads to So12,(ThOF2,s) = 239.3 h 3 J K-I mol-], as compared to the tabulated value of 238.2 J K-' mol-I. These tabulated functions appear reasonable and can be used in subsequent analysis. From the equilibrium data in Table I1 and thermal functions for ThF,(g)? ThO2(s),Io and ThOF2(s),, one obtains the third-law result AH0298(1) = 35 1.5 kJ mol-'; the corresponding second-law value at 298 K is 349.0 kJ mol-', in good accord. An uncertainty of 3 kJ mol-' is assigned to the preferred third-law result. This third-law result for reaction 1, when used with auxiliary data for ThF4(g),a4 and Th02(s),lo yields the standard enthalpy of formation AHro298(Th0F2,s) =-1668 f 3 kJ mol-', in close agreement with the selected value of Fuger et aL2 based on the measurements of Darnell,'-1669 f 10 kJ mol-'. Discussion Our derived equilibrium pressures for reaction 1 are about 20% higher than those obtained by Darnell,' as calculated from the selected thermodynamic data of Fuger et aL2 This is not a large difference, but the results are in any event now more readily accessible. In addition, the vapor composition has been directly verified. (IO) Pankratz, L. B. Bull.-US., Bur. Mines 1982, No. 672. From the well-established values for ThF4(s), and ThO2(s),I0 and the new results on ThOF,(s), one calculates for the reaction ThF,(s) + ThO,(s) = ZThOF,(s) (2) the enthalpy change AH0298(2) =-13.0 kJ mol-'. Similarly, the relative equilibrium pressures of ThF,(s) and ThOF2(s) yield the Gibbs energy change AC01200 =-8.2 kJ mol-'. These relatively small values show that ThOF,(s) is only marginally stable with respect to the constituent oxide and fluoride. However, this small driving force is sufficient to generate an orthorhombic ThOF,(s) phase from cubic ThO,(s) and monoclinic ThF4(s). The low stability of the oxyfluoride phase with respect to decomposition does not preclude the existence of stable gaseous oxyfluorides. We have already identified and characterized gaseous ThOF4 and likewise found evidence for the presence of gaseous ThOF, from the ionization efficiency curve of ThOF'. Our results presented here show only that the gaseous oxyfluorides cannot be generated by sublimation of ThOF2(s). With a relatively involatile oxide and a more volatile fluoride, the gaseous oxyfluorides can only be generated by fluorination of the oxide at much higher temperatures, in the range 1800-2000 K.

Several shielding applications, to protect human health and electronic devices against dangerous ... more Several shielding applications, to protect human health and electronic devices against dangerous effects of electromagnetic radiation, require solutions that fabrics can suitably fulfill. Here, we will discuss the electromagnetic interference shielding effectiveness of polypyrrole-coated polyester nonwoven textiles, in the frequency range 100—800 MHz. Insertion losses for samples with different surface resistivity ranging from 40 Ω/sq till the very low value of 3 Ω/sq were measured with a dual-transverse electromagnetic cell. We found a correlation between the shielding effectiveness and the surface conductivity of composites. For the sample with the lowest surface resistivity, we obtained an electromagnetic shielding effectiveness of 37 dB.

MSA, 2010

Polypyrrole can be chemically synthesized on PET fabrics, giving rise to textiles with high elect... more Polypyrrole can be chemically synthesized on PET fabrics, giving rise to textiles with high electric conductivity. These textiles are suitable for several applications from antistatic films to electromagnetic interference shielding devices. Here we discuss the thermal-electric performance and the heat generation of polypyrrole coated PET fabric samples, previously studied because of their electric conductivity and electromagnetic interference shielding effectiveness. The measured Seebeck effect is comparable with that of metallic thermocouples. Since polypyrrole shows extremely low thermal diffusivities regardless of the electrical conductivity, the low thermal conductivity gives significant advantage to the thermoelectric figure-of-merit ZT, comparable with that of some traditional inorganic thermoelectric materials. The heat generation is also investigated for possible heating textile devices. The results confirm polypyrrole as a promising material for thermal electric applications due to its easy preparation in low cost processing.

Eeonyx Corp. has developed a line of conductive polymer coatings that can be applied to fabrics, ... more Eeonyx Corp. has developed a line of conductive polymer coatings that can be applied to fabrics, felts, foams, films, powders, and plastic parts over a large range of tunable resistances. Materials of almost any composition, including silicones, polyolefins, and fluoropolymers, can be made conductive by the Eeonyx proprietary process. EeonTex(TM) fabrics are lightly colored, totally uniformly conductive fabrics that possess excellent resistance to heat, humidity, UV radiation, sloughing, and cleanroom/ordinary laundering. The use of EeonTex fabrics in biomedical instruments, sensors, antennas, resistive heaters, static control, cleanrooms, automobiles, and military-related applications will be discussed. Coating conductive polymers onto powdered carbonaceous substrates leads to conductive additives, called Eeonomers(R), that possess excellent thermal stability, advanced electrical properties, and superior blending characteristics. Applications of Eeonomers in electronics packaging w...

Particle & Particle Systems Characterization, 1996

ABSTRACT

Journal of Thermoplastic Composite Materials, 2007

Materials for electromagnetic shielding are increasingly needed to protect electronic devices fro... more Materials for electromagnetic shielding are increasingly needed to protect electronic devices from interference problems and to avoid dangerous effects on human health due to electromagnetic radiation. Several shielding applications require solutions that textiles can suitably fulfill. Here the electromagnetic interference shielding of metallized, PPy-coated woven and non-woven polyester fabrics is provided in the frequency range 100—1000 MHz, measuring the insertion losses produced by these conductive fabrics in a dual TEM cell. From the insertion loss data, the shielding effectiveness, and the reflection and absorption coefficients are estimated.

Journal of Materials Science, 1990

The degree of fibrillation of a reinforcing fibre can be viewed as the extent to which the fibre ... more The degree of fibrillation of a reinforcing fibre can be viewed as the extent to which the fibre has partially been split longitudinally into thinner fibrils. Fibrillation provides larger surface area and is advantageous because it improves matrix-to-fibre coupling, oil absorption, thickening characteristics, and softness of the fibre. Fibrillation also allows for low bulk density and assists the mat-making capability of the fibre. A general means for quantifying the degree of fibrillation of a fibre is proposed. Taking the squared ratio of the fibre surface area determined by the BET method to that determined by measuring a sampling of many particles in a scanning electron micrograph, the technique for which is described herein, one has a quantitative, relatively simple method for calculating the degree of fibrillation. Results for calcium sodium metaphosphate fibre, a new inorganic fibre developed by Monsanto [1], milled glass fibre, and wollastonite fibre are reported and compared. Benefits of fibrillation are discussed.

Biophysical Chemistry, 2003

The surface tension (excess surface free energy) of water is an important factor in many biologic... more The surface tension (excess surface free energy) of water is an important factor in many biological and chemical systems. It is often invoked to correlate or explain the low solubility of nonpolar compounds in water as well as the so-called hydrophobic effect of nonpolar molecules aggregating in water. While water's surface tension is not easily obtained from theory, the random network model (RNM) of Henn and Kauzmann (H-K), which described water's well-known, anomalous thermodynamic properties, can be used successfully to calculate the surface tension of water at atmospheric pressure between temperatures of 0 and 100 8C. Agreement with observed values, particularly at lower temperatures, is good, although the H-K RNM is too ice-like in nature to allow for the rapid drop off of surface tension with increasing temperature. Suggestions are offered for improving the model. In addition, an alternative explanation for the preferred orientation of surface water molecules is proposed based on water's H-bonding and attendant intramolecular, zero-point distortion energy.

Biophysical Chemistry, 2002

The Barclay-Butler (B-B) rule, which states that a linear relationship exists between the standar... more The Barclay-Butler (B-B) rule, which states that a linear relationship exists between the standard deltaH(vap) and deltaS(vap) for simple, non-associated liquids and their solutions, has been used to distinguish associated ('abnormal') liquids from simple ('normal') liquids. The exact character of the B-B plots depends on the standard states chosen for the liquid/solution and vapor. We examine the effects of using number density for both vapor and liquid states for pure liquids, non-aqueous solutions, aqueous solutions and solutions in which water is the solute. The utility of B-B plots to detect solute-induced order is strengthened, and we also find remarkable changes in the modified B-B relationship: (1) the points for small, H-bonded liquids, including water, are pulled below the general B-B line; (2) many solutions containing small, simple solutes have negative entropies of vaporization; and (3) solutions of water in several organic solvents, relevant to studies of proteins and micelles, appear 'abnormal'.

International Symposium on Electromagnetic Compatibility, 1992

ABSTRACT

in the group of Professor Alan G. MacDiarmid, who was awarded the Nobel Prize in chemistry in 200... more in the group of Professor Alan G. MacDiarmid, who was awarded the Nobel Prize in chemistry in 2000 for co-discovery of CP's. There, Dr. Avloni worked (1991-1995) on synthesis, characterization, blending and processing of CP materials. He was the first to demonstrate the effect of CP molecular conformation on their electrical conductivity. Dr. Arthur Henn, Pres. of Marktek Inc., has been involved with conductive textiles for 18 years. Prior to founding Marktek Inc. in 1994, he was one of the key team leaders in the technical and commercial development of Flectron® metalized materials at Monsanto Co.

The Journal of Physical Chemistry, 1989

we derive A.So1200 = 171.1 f 3 J K-I mol-' for reaction 1 using the second-law method; when combi... more we derive A.So1200 = 171.1 f 3 J K-I mol-' for reaction 1 using the second-law method; when combined with entropy data for ThF4(g), and Th02(s),'0 this leads to So12,(ThOF2,s) = 239.3 h 3 J K-I mol-], as compared to the tabulated value of 238.2 J K-' mol-I. These tabulated functions appear reasonable and can be used in subsequent analysis. From the equilibrium data in Table I1 and thermal functions for ThF,(g)? ThO2(s),Io and ThOF2(s),, one obtains the third-law result AH0298(1) = 35 1.5 kJ mol-'; the corresponding second-law value at 298 K is 349.0 kJ mol-', in good accord. An uncertainty of 3 kJ mol-' is assigned to the preferred third-law result. This third-law result for reaction 1, when used with auxiliary data for ThF4(g),a4 and Th02(s),lo yields the standard enthalpy of formation AHro298(Th0F2,s) =-1668 f 3 kJ mol-', in close agreement with the selected value of Fuger et aL2 based on the measurements of Darnell,'-1669 f 10 kJ mol-'. Discussion Our derived equilibrium pressures for reaction 1 are about 20% higher than those obtained by Darnell,' as calculated from the selected thermodynamic data of Fuger et aL2 This is not a large difference, but the results are in any event now more readily accessible. In addition, the vapor composition has been directly verified. (IO) Pankratz, L. B. Bull.-US., Bur. Mines 1982, No. 672. From the well-established values for ThF4(s), and ThO2(s),I0 and the new results on ThOF,(s), one calculates for the reaction ThF,(s) + ThO,(s) = ZThOF,(s) (2) the enthalpy change AH0298(2) =-13.0 kJ mol-'. Similarly, the relative equilibrium pressures of ThF,(s) and ThOF2(s) yield the Gibbs energy change AC01200 =-8.2 kJ mol-'. These relatively small values show that ThOF,(s) is only marginally stable with respect to the constituent oxide and fluoride. However, this small driving force is sufficient to generate an orthorhombic ThOF,(s) phase from cubic ThO,(s) and monoclinic ThF4(s). The low stability of the oxyfluoride phase with respect to decomposition does not preclude the existence of stable gaseous oxyfluorides. We have already identified and characterized gaseous ThOF4 and likewise found evidence for the presence of gaseous ThOF, from the ionization efficiency curve of ThOF'. Our results presented here show only that the gaseous oxyfluorides cannot be generated by sublimation of ThOF2(s). With a relatively involatile oxide and a more volatile fluoride, the gaseous oxyfluorides can only be generated by fluorination of the oxide at much higher temperatures, in the range 1800-2000 K.

Several shielding applications, to protect human health and electronic devices against dangerous ... more Several shielding applications, to protect human health and electronic devices against dangerous effects of electromagnetic radiation, require solutions that fabrics can suitably fulfill. Here, we will discuss the electromagnetic interference shielding effectiveness of polypyrrole-coated polyester nonwoven textiles, in the frequency range 100—800 MHz. Insertion losses for samples with different surface resistivity ranging from 40 Ω/sq till the very low value of 3 Ω/sq were measured with a dual-transverse electromagnetic cell. We found a correlation between the shielding effectiveness and the surface conductivity of composites. For the sample with the lowest surface resistivity, we obtained an electromagnetic shielding effectiveness of 37 dB.

MSA, 2010

Polypyrrole can be chemically synthesized on PET fabrics, giving rise to textiles with high elect... more Polypyrrole can be chemically synthesized on PET fabrics, giving rise to textiles with high electric conductivity. These textiles are suitable for several applications from antistatic films to electromagnetic interference shielding devices. Here we discuss the thermal-electric performance and the heat generation of polypyrrole coated PET fabric samples, previously studied because of their electric conductivity and electromagnetic interference shielding effectiveness. The measured Seebeck effect is comparable with that of metallic thermocouples. Since polypyrrole shows extremely low thermal diffusivities regardless of the electrical conductivity, the low thermal conductivity gives significant advantage to the thermoelectric figure-of-merit ZT, comparable with that of some traditional inorganic thermoelectric materials. The heat generation is also investigated for possible heating textile devices. The results confirm polypyrrole as a promising material for thermal electric applications due to its easy preparation in low cost processing.

Eeonyx Corp. has developed a line of conductive polymer coatings that can be applied to fabrics, ... more Eeonyx Corp. has developed a line of conductive polymer coatings that can be applied to fabrics, felts, foams, films, powders, and plastic parts over a large range of tunable resistances. Materials of almost any composition, including silicones, polyolefins, and fluoropolymers, can be made conductive by the Eeonyx proprietary process. EeonTex(TM) fabrics are lightly colored, totally uniformly conductive fabrics that possess excellent resistance to heat, humidity, UV radiation, sloughing, and cleanroom/ordinary laundering. The use of EeonTex fabrics in biomedical instruments, sensors, antennas, resistive heaters, static control, cleanrooms, automobiles, and military-related applications will be discussed. Coating conductive polymers onto powdered carbonaceous substrates leads to conductive additives, called Eeonomers(R), that possess excellent thermal stability, advanced electrical properties, and superior blending characteristics. Applications of Eeonomers in electronics packaging w...

Particle & Particle Systems Characterization, 1996

ABSTRACT

Journal of Thermoplastic Composite Materials, 2007

Materials for electromagnetic shielding are increasingly needed to protect electronic devices fro... more Materials for electromagnetic shielding are increasingly needed to protect electronic devices from interference problems and to avoid dangerous effects on human health due to electromagnetic radiation. Several shielding applications require solutions that textiles can suitably fulfill. Here the electromagnetic interference shielding of metallized, PPy-coated woven and non-woven polyester fabrics is provided in the frequency range 100—1000 MHz, measuring the insertion losses produced by these conductive fabrics in a dual TEM cell. From the insertion loss data, the shielding effectiveness, and the reflection and absorption coefficients are estimated.

Journal of Materials Science, 1990

The degree of fibrillation of a reinforcing fibre can be viewed as the extent to which the fibre ... more The degree of fibrillation of a reinforcing fibre can be viewed as the extent to which the fibre has partially been split longitudinally into thinner fibrils. Fibrillation provides larger surface area and is advantageous because it improves matrix-to-fibre coupling, oil absorption, thickening characteristics, and softness of the fibre. Fibrillation also allows for low bulk density and assists the mat-making capability of the fibre. A general means for quantifying the degree of fibrillation of a fibre is proposed. Taking the squared ratio of the fibre surface area determined by the BET method to that determined by measuring a sampling of many particles in a scanning electron micrograph, the technique for which is described herein, one has a quantitative, relatively simple method for calculating the degree of fibrillation. Results for calcium sodium metaphosphate fibre, a new inorganic fibre developed by Monsanto [1], milled glass fibre, and wollastonite fibre are reported and compared. Benefits of fibrillation are discussed.

Biophysical Chemistry, 2003

The surface tension (excess surface free energy) of water is an important factor in many biologic... more The surface tension (excess surface free energy) of water is an important factor in many biological and chemical systems. It is often invoked to correlate or explain the low solubility of nonpolar compounds in water as well as the so-called hydrophobic effect of nonpolar molecules aggregating in water. While water's surface tension is not easily obtained from theory, the random network model (RNM) of Henn and Kauzmann (H-K), which described water's well-known, anomalous thermodynamic properties, can be used successfully to calculate the surface tension of water at atmospheric pressure between temperatures of 0 and 100 8C. Agreement with observed values, particularly at lower temperatures, is good, although the H-K RNM is too ice-like in nature to allow for the rapid drop off of surface tension with increasing temperature. Suggestions are offered for improving the model. In addition, an alternative explanation for the preferred orientation of surface water molecules is proposed based on water's H-bonding and attendant intramolecular, zero-point distortion energy.

Biophysical Chemistry, 2002

The Barclay-Butler (B-B) rule, which states that a linear relationship exists between the standar... more The Barclay-Butler (B-B) rule, which states that a linear relationship exists between the standard deltaH(vap) and deltaS(vap) for simple, non-associated liquids and their solutions, has been used to distinguish associated ('abnormal') liquids from simple ('normal') liquids. The exact character of the B-B plots depends on the standard states chosen for the liquid/solution and vapor. We examine the effects of using number density for both vapor and liquid states for pure liquids, non-aqueous solutions, aqueous solutions and solutions in which water is the solute. The utility of B-B plots to detect solute-induced order is strengthened, and we also find remarkable changes in the modified B-B relationship: (1) the points for small, H-bonded liquids, including water, are pulled below the general B-B line; (2) many solutions containing small, simple solutes have negative entropies of vaporization; and (3) solutions of water in several organic solvents, relevant to studies of proteins and micelles, appear 'abnormal'.