Vijaya G - Academia.edu (original) (raw)
Papers by Vijaya G
HE role of information technology in increasing the overall productivity of the U.S. economy is n... more HE role of information technology in increasing the overall productivity of the U.S. economy is now being widely recognized. Within the economics profession, there is an ongoing discussion as to whether or not information technology has increased the longrun speed limit of the economy or is simply a shortrun phenomenon. In other words, do recent economic conditions support the notion of a new economy in which the improvement in productivity is secular rather than cyclical?
Journal of Econometrics, 1999
This paper incorporates infrastructure into the production function as part of the technological ... more This paper incorporates infrastructure into the production function as part of the technological constraint rather than as a discretionary factor input. Our theoretical model speci"es a technological growth rate as a nonlinear function of infrastructure and a time trend, the latter capturing the e!ect of all other variables on the growth rate in technology. The time trend and infrastructure are modeled so as to be interactive rather than additive. The functional form estimated allows for a &S'-shaped production function which embodies not only the properties of a long-run production function but also those exhibited in the short run.
Journal of Econometrics, 2007
This paper incorporates both public and private infrastructure within the framework of a nonlinea... more This paper incorporates both public and private infrastructure within the framework of a nonlinear production function. The theoretical model specifies a technological growth rate as a nonlinear function of government infrastructure and private infrastructure generated by the ...
Energy Economics, 1993
... the positive effect due to the impact of income on ecological consciousness, de ... and J. Ba... more ... the positive effect due to the impact of income on ecological consciousness, de ... and J. Baily, EPA sets rules for pollution curbs on state landfills', Wall Street ... House, Trading Off Environment, Economics, and Energy: EPA's Strategic Environmental Assessment System, Lexington ...
HE role of information technology in increasing the overall productivity of the U.S. economy is n... more HE role of information technology in increasing the overall productivity of the U.S. economy is now being widely recognized. Within the economics profession, there is an ongoing discussion as to whether or not information technology has increased the longrun speed limit of the economy or is simply a shortrun phenomenon. In other words, do recent economic conditions support the notion of a new economy in which the improvement in productivity is secular rather than cyclical?
Journal of Econometrics, 1999
This paper incorporates infrastructure into the production function as part of the technological ... more This paper incorporates infrastructure into the production function as part of the technological constraint rather than as a discretionary factor input. Our theoretical model speci"es a technological growth rate as a nonlinear function of infrastructure and a time trend, the latter capturing the e!ect of all other variables on the growth rate in technology. The time trend and infrastructure are modeled so as to be interactive rather than additive. The functional form estimated allows for a &S'-shaped production function which embodies not only the properties of a long-run production function but also those exhibited in the short run.
Journal of Econometrics, 2007
This paper incorporates both public and private infrastructure within the framework of a nonlinea... more This paper incorporates both public and private infrastructure within the framework of a nonlinear production function. The theoretical model specifies a technological growth rate as a nonlinear function of government infrastructure and private infrastructure generated by the ...
Energy Economics, 1993
... the positive effect due to the impact of income on ecological consciousness, de ... and J. Ba... more ... the positive effect due to the impact of income on ecological consciousness, de ... and J. Baily, EPA sets rules for pollution curbs on state landfills', Wall Street ... House, Trading Off Environment, Economics, and Energy: EPA's Strategic Environmental Assessment System, Lexington ...
Journal of Food Engineering, 2007
Dielectric properties of butter with and without salt (moisture content 17-19%) were measured ove... more Dielectric properties of butter with and without salt (moisture content 17-19%) were measured over the MW frequency range covering 500-3000 MHz. The effect of temperature on dielectric properties of butter was studied at 10°interval between 30 and 80°C. Results indicated that dielectric spectra of unsalted butter differed significantly (P < 0.05) from the salted one as function of temperature. The dielectric constant (e 0 ) of unsalted butter was independent of frequency whereas the loss factor (e 00 ) decreased with an increase in frequency. Both e 0 and e 00 of unsalted butter decreased as the temperature increased. Dielectric parameters of salted butter gradually decreased with increasing frequency but increased with temperature. The dielectric properties of both salted and unsalted butter were adequately described by a second order polynomial equation. The increase in ionic conductance as a result of salt appears to be the principal reason for the differences in electrical properties of salted butter. Butter converted to butter oil (at elevated temperatures) exhibited significant drop in dielectric parameters possibly due to the lack of water. Power penetration depth of butter decreased with temperature, frequency, and salt content.
International Journal of Food Properties, 2007
Gel properties of radio frequency (RF) heated egg white dispersions at 27.12 MHz were studied as ... more Gel properties of radio frequency (RF) heated egg white dispersions at 27.12 MHz were studied as function of concentration (2.5–2.5 kg/100 kg sample), pH (3–11) and heating time (60–180 s). Egg white dispersions demonstrated a gradual liquid-solid transformation as they denatured and gelled during RF treatment. The critical concentration and heating period for egg white protein denaturation and gelation were found to be 7.5% (w/w) and 150 seconds. The elastic modulus (G′) of RF-heated samples increased with concentration and heating period (temperature), whereas complex viscosity (η*) increased exponentially with concentration. In an alkaline condition, the egg white dispersion did not produce a gel; however, in acidic condition it resulted in a strong gel with significantly (P < 0.05) higher G′. This could be attributed to the high dielectric constant (ε′) and loss factor (ε″) values of acidified samples as compared to the alkaline and control egg white dispersion. Effect of heating rate (1, 5, 10, and 20°C/min) in situ on rheometer plate significantly affected gel rigidity; the RF treated sample rigidity was comparable to samples heated at the rate of 5 and 10°C/min. Differential scanning calorimetry, dielectric measurement, and sodium dodecyl sulfate (SDS) PAGE electrophoresis results were used to confirm gelation behavior during both conventional and RF heating conditions.
Journal of Food Science, 1997
The individual effects of heating time (15–120 min), pH (3–9) and NaCl (0–2M), sucrose (0–30% w/v... more The individual effects of heating time (15–120 min), pH (3–9) and NaCl (0–2M), sucrose (0–30% w/v) and protein (10–30% w/v) concentrations on the strength, turbidity and water holding capacity were investigated on a commercial whey protein concentrate (WPC, 75% protein) when heated at temperatures ranging from 65 to 90°C. Interactive effects were investigated using a four-variable, five-level central composite rotatable design (CCRD) analyzed by response surface methodology (RSM). Gel strength (GS) and water holding capacity (WHC) increased with protein concentration, heating temperature and time. Increasing sucrose concentration decreased GS but increased WHC. Increasing NaCl concentration increased GS and WHC below pH 5 but resulted in weaker gels at high pH (>7).
Journal of Cereal Science, 2008
Dynamic oscillatory rheology of two wheat protein isolate (Prolite 100 and Prolite 200) doughs (E... more Dynamic oscillatory rheology of two wheat protein isolate (Prolite 100 and Prolite 200) doughs (E48% moisture content, wet basis) were studied over a frequency range of 0.1-10 Hz during temperature sweep from 20 to 90 1C at a heating rate of 2 1C/min. Both doughs behaved similarly during heating; showed a threshold value and increased sharply, thereafter. Prolite 200 dough had a higher elastic modulus (G 0 ) and lower phase angle (d) whereas Prolite 100 showed a distinct gel point at 52.2 1C followed by significant increase up to 90 1C. Rheological data of doughs after isothermal heating at 90 1C for 15 min followed by cooling to 20 1C resulted in strong mechanical strength. However, Prolite 100 dough showed more viscoelastic characteristics with significant transformation from liquid-like to solidlike behavior after heating than Prolite 200. Thermal analysis of isolates indicated distinct endothermic peaks in wider temperature range (50-130 1C) at various moisture levels. Lower temperatures could be associated with denaturation of various fractions of proteins whereas higher temperature linked to glass transition temperature of isolates. SDS-PAGE did not show any clear distinction among protein subunits between two isolates. Dielectric measurements of isolates at frequencies from 500 to 3000 MHz and temperature range between 30 and 80 1C indicated Prolite 200 had higher dielectric constant (e 0 ) and loss factor (e 00 ) than Prolite 100. Isolates showed significant changes in dielectric properties above 50 1C indicating protein denaturation and supported rheological and calorimetric data. r
Journal of Food Engineering, 2007
Dielectric properties of Indian Basmati rice samples (dry ground flour and wet aqueous slurry) we... more Dielectric properties of Indian Basmati rice samples (dry ground flour and wet aqueous slurry) were measured over the frequency range 500-2500 MHz. Temperature dependence of dielectric properties of rice flour slurries (20, 30 and 50 g flour per 100 g water yielding approximately 1:5, 1:3 and 1:2 flour to water ratio) were studied between 30 and 80°C. Results indicated that dielectric constants (e 0 ) generally did not vary with frequency while the loss factor (e 00 ) showed an increasing trend. A sharp change in dielectric parameters were noted above 70°C attributable to rice starch gelatinization, an observation confirmed later by differential scanning calorimetry. An increase in flour slurry concentration systematically reduced e 0 during the entire frequency range while variations in e 00 values were mixed. Addition of 1% salt markedly increased e 00 of slurries whereas butter resulted in significant reduction in e 0 values. Rice flour slurry containing both salt and butter exhibited intermediate values of dielectric properties. Both e 0 and e 00 data of rice slurries generally fitted a 2nd order polynomial relationship with temperature. These results suggest that dielectric measurements could be used to study frequency, concentration, ingredient and temperature dependent changes in starch-water systems during heating.
HE role of information technology in increasing the overall productivity of the U.S. economy is n... more HE role of information technology in increasing the overall productivity of the U.S. economy is now being widely recognized. Within the economics profession, there is an ongoing discussion as to whether or not information technology has increased the longrun speed limit of the economy or is simply a shortrun phenomenon. In other words, do recent economic conditions support the notion of a new economy in which the improvement in productivity is secular rather than cyclical?
Journal of Econometrics, 1999
This paper incorporates infrastructure into the production function as part of the technological ... more This paper incorporates infrastructure into the production function as part of the technological constraint rather than as a discretionary factor input. Our theoretical model speci"es a technological growth rate as a nonlinear function of infrastructure and a time trend, the latter capturing the e!ect of all other variables on the growth rate in technology. The time trend and infrastructure are modeled so as to be interactive rather than additive. The functional form estimated allows for a &S'-shaped production function which embodies not only the properties of a long-run production function but also those exhibited in the short run.
Journal of Econometrics, 2007
This paper incorporates both public and private infrastructure within the framework of a nonlinea... more This paper incorporates both public and private infrastructure within the framework of a nonlinear production function. The theoretical model specifies a technological growth rate as a nonlinear function of government infrastructure and private infrastructure generated by the ...
Energy Economics, 1993
... the positive effect due to the impact of income on ecological consciousness, de ... and J. Ba... more ... the positive effect due to the impact of income on ecological consciousness, de ... and J. Baily, EPA sets rules for pollution curbs on state landfills', Wall Street ... House, Trading Off Environment, Economics, and Energy: EPA's Strategic Environmental Assessment System, Lexington ...
HE role of information technology in increasing the overall productivity of the U.S. economy is n... more HE role of information technology in increasing the overall productivity of the U.S. economy is now being widely recognized. Within the economics profession, there is an ongoing discussion as to whether or not information technology has increased the longrun speed limit of the economy or is simply a shortrun phenomenon. In other words, do recent economic conditions support the notion of a new economy in which the improvement in productivity is secular rather than cyclical?
Journal of Econometrics, 1999
This paper incorporates infrastructure into the production function as part of the technological ... more This paper incorporates infrastructure into the production function as part of the technological constraint rather than as a discretionary factor input. Our theoretical model speci"es a technological growth rate as a nonlinear function of infrastructure and a time trend, the latter capturing the e!ect of all other variables on the growth rate in technology. The time trend and infrastructure are modeled so as to be interactive rather than additive. The functional form estimated allows for a &S'-shaped production function which embodies not only the properties of a long-run production function but also those exhibited in the short run.
Journal of Econometrics, 2007
This paper incorporates both public and private infrastructure within the framework of a nonlinea... more This paper incorporates both public and private infrastructure within the framework of a nonlinear production function. The theoretical model specifies a technological growth rate as a nonlinear function of government infrastructure and private infrastructure generated by the ...
Energy Economics, 1993
... the positive effect due to the impact of income on ecological consciousness, de ... and J. Ba... more ... the positive effect due to the impact of income on ecological consciousness, de ... and J. Baily, EPA sets rules for pollution curbs on state landfills', Wall Street ... House, Trading Off Environment, Economics, and Energy: EPA's Strategic Environmental Assessment System, Lexington ...
Journal of Food Engineering, 2007
Dielectric properties of butter with and without salt (moisture content 17-19%) were measured ove... more Dielectric properties of butter with and without salt (moisture content 17-19%) were measured over the MW frequency range covering 500-3000 MHz. The effect of temperature on dielectric properties of butter was studied at 10°interval between 30 and 80°C. Results indicated that dielectric spectra of unsalted butter differed significantly (P < 0.05) from the salted one as function of temperature. The dielectric constant (e 0 ) of unsalted butter was independent of frequency whereas the loss factor (e 00 ) decreased with an increase in frequency. Both e 0 and e 00 of unsalted butter decreased as the temperature increased. Dielectric parameters of salted butter gradually decreased with increasing frequency but increased with temperature. The dielectric properties of both salted and unsalted butter were adequately described by a second order polynomial equation. The increase in ionic conductance as a result of salt appears to be the principal reason for the differences in electrical properties of salted butter. Butter converted to butter oil (at elevated temperatures) exhibited significant drop in dielectric parameters possibly due to the lack of water. Power penetration depth of butter decreased with temperature, frequency, and salt content.
International Journal of Food Properties, 2007
Gel properties of radio frequency (RF) heated egg white dispersions at 27.12 MHz were studied as ... more Gel properties of radio frequency (RF) heated egg white dispersions at 27.12 MHz were studied as function of concentration (2.5–2.5 kg/100 kg sample), pH (3–11) and heating time (60–180 s). Egg white dispersions demonstrated a gradual liquid-solid transformation as they denatured and gelled during RF treatment. The critical concentration and heating period for egg white protein denaturation and gelation were found to be 7.5% (w/w) and 150 seconds. The elastic modulus (G′) of RF-heated samples increased with concentration and heating period (temperature), whereas complex viscosity (η*) increased exponentially with concentration. In an alkaline condition, the egg white dispersion did not produce a gel; however, in acidic condition it resulted in a strong gel with significantly (P < 0.05) higher G′. This could be attributed to the high dielectric constant (ε′) and loss factor (ε″) values of acidified samples as compared to the alkaline and control egg white dispersion. Effect of heating rate (1, 5, 10, and 20°C/min) in situ on rheometer plate significantly affected gel rigidity; the RF treated sample rigidity was comparable to samples heated at the rate of 5 and 10°C/min. Differential scanning calorimetry, dielectric measurement, and sodium dodecyl sulfate (SDS) PAGE electrophoresis results were used to confirm gelation behavior during both conventional and RF heating conditions.
Journal of Food Science, 1997
The individual effects of heating time (15–120 min), pH (3–9) and NaCl (0–2M), sucrose (0–30% w/v... more The individual effects of heating time (15–120 min), pH (3–9) and NaCl (0–2M), sucrose (0–30% w/v) and protein (10–30% w/v) concentrations on the strength, turbidity and water holding capacity were investigated on a commercial whey protein concentrate (WPC, 75% protein) when heated at temperatures ranging from 65 to 90°C. Interactive effects were investigated using a four-variable, five-level central composite rotatable design (CCRD) analyzed by response surface methodology (RSM). Gel strength (GS) and water holding capacity (WHC) increased with protein concentration, heating temperature and time. Increasing sucrose concentration decreased GS but increased WHC. Increasing NaCl concentration increased GS and WHC below pH 5 but resulted in weaker gels at high pH (>7).
Journal of Cereal Science, 2008
Dynamic oscillatory rheology of two wheat protein isolate (Prolite 100 and Prolite 200) doughs (E... more Dynamic oscillatory rheology of two wheat protein isolate (Prolite 100 and Prolite 200) doughs (E48% moisture content, wet basis) were studied over a frequency range of 0.1-10 Hz during temperature sweep from 20 to 90 1C at a heating rate of 2 1C/min. Both doughs behaved similarly during heating; showed a threshold value and increased sharply, thereafter. Prolite 200 dough had a higher elastic modulus (G 0 ) and lower phase angle (d) whereas Prolite 100 showed a distinct gel point at 52.2 1C followed by significant increase up to 90 1C. Rheological data of doughs after isothermal heating at 90 1C for 15 min followed by cooling to 20 1C resulted in strong mechanical strength. However, Prolite 100 dough showed more viscoelastic characteristics with significant transformation from liquid-like to solidlike behavior after heating than Prolite 200. Thermal analysis of isolates indicated distinct endothermic peaks in wider temperature range (50-130 1C) at various moisture levels. Lower temperatures could be associated with denaturation of various fractions of proteins whereas higher temperature linked to glass transition temperature of isolates. SDS-PAGE did not show any clear distinction among protein subunits between two isolates. Dielectric measurements of isolates at frequencies from 500 to 3000 MHz and temperature range between 30 and 80 1C indicated Prolite 200 had higher dielectric constant (e 0 ) and loss factor (e 00 ) than Prolite 100. Isolates showed significant changes in dielectric properties above 50 1C indicating protein denaturation and supported rheological and calorimetric data. r
Journal of Food Engineering, 2007
Dielectric properties of Indian Basmati rice samples (dry ground flour and wet aqueous slurry) we... more Dielectric properties of Indian Basmati rice samples (dry ground flour and wet aqueous slurry) were measured over the frequency range 500-2500 MHz. Temperature dependence of dielectric properties of rice flour slurries (20, 30 and 50 g flour per 100 g water yielding approximately 1:5, 1:3 and 1:2 flour to water ratio) were studied between 30 and 80°C. Results indicated that dielectric constants (e 0 ) generally did not vary with frequency while the loss factor (e 00 ) showed an increasing trend. A sharp change in dielectric parameters were noted above 70°C attributable to rice starch gelatinization, an observation confirmed later by differential scanning calorimetry. An increase in flour slurry concentration systematically reduced e 0 during the entire frequency range while variations in e 00 values were mixed. Addition of 1% salt markedly increased e 00 of slurries whereas butter resulted in significant reduction in e 0 values. Rice flour slurry containing both salt and butter exhibited intermediate values of dielectric properties. Both e 0 and e 00 data of rice slurries generally fitted a 2nd order polynomial relationship with temperature. These results suggest that dielectric measurements could be used to study frequency, concentration, ingredient and temperature dependent changes in starch-water systems during heating.