Vapor Conductance Research Articles

Thermal properties of mercury on the basis of model potentials

Calculation tools for the second and third virial coefficients and collision integrals are developed on the basis of model potentials. Five model potentials are considered and analyzed for mercury. By the model potential selected from them, the second and third virial coefficients are calculated for mercury vapor. The additive and nonadditive components in the third virial coefficient are taken into account. Viscosity and heat conductivity of the rarefied vapor are calculated by collision integrals on the basis of the selected model potential.

A model to predict the effect of surface wettability on critical heat flux

Critical heat flux (CHF) in pool boiling experiments corresponds to the heat flux at which a vapor film is formed on the heated surface resulting from the replacement of liquid by vapor adjacent to this surface. Poor thermal conductivity of vapor can severely deteriorate heat transfer. It is important that systems operate below this limit which is a strong limitation to heat transfer due to the huge increase of the thermal resistance near the wall. The concept of macro- and micro-contact angles has been introduced in a previous paper (Phan et al., 2010 [28]) to describe the bubble growth processes. In this paper, an explicit relation between the bubble departure diameter and the contact angle has been presented. Based on these results, we propose a model of critical heat flux, taking into account the effects of the wettability of the fluid, whose property is known to strongly influence boiling heat transfer. A new correlation for CHF, dependent on the contact angle, is proposed. It is found in fair agreement with existing experimental results concerning subcooled boiling to describe the variation of CHF with wettability.

Temperature dependence of the electrical conductivity of vapor grown carbon nanofiber/epoxy composites with different filler dispersion levels

The influence of the dispersion of vapor grown carbon nanofibers (VGCNF) on the electrical properties of VGCNF/epoxy composites has been studied. A homogeneous dispersion of the VGCNF does not imply better electrical properties. The presence of well distributed clusters appears to be a key factor for increasing composite conductivity. It is also shown that the main conduction mechanism has an ionic nature for concentrations below the percolation threshold, while above the percolation threshold it is dominated by hopping between the fillers. Finally, using the granular system theory it is possible to explain the origin of conduction at low temperatures.

The Impact of Wire Environment on Electro-Explosive Fuse Performance

The environment surrounding an exploding wire is known be a controlling factor in electro-explosive fuse performance. Recent experiments have shown that the application of an insulating surface coating to the fuse wire can significantly increase the rate of impedance transition and impedance magnitude of the exploding wire. This paper discusses the performance of surface coated fuses tested in commonly used solid and gaseous media. For comparison, these experiments are compared to bare wire fuse experiments in identical environments. Previously developed exploding wire models are utilized to aid in the interpretation of the experimental fuse behavior. Differential wire voltage, voltage pulse length, and degree of post vaporization conduction (i.e., restrike) are discussed for each experiment.

Effect of salinity on canopy water vapor conductance of young and 3-year old Jatropha curcas L.

With increasing demand for biofuels, jatropha is considered as one of the biofuel crops, which is suitable for growth under adverse conditions including drought and salinity which mainly occur in arid and semi-arid environment. We report here to what extent salt stress affected water loss, canopy water vapor conductance, leaf growth and Na and K concentrations of leaves of 3-year old and young plants. Adult (on peat substrate) and young (in hydroponic system) plants were exposed to seven (0–300 mmol NaCl L−1) and five salt levels (0–200 mmol NaCl L−1), during 20 and 6 days, respectively.In both experiments, plants responded rapidly to salt stress by reducing water loss. The threshold value of responses was between 0 and 5 dS m−1. Leaf area increment of young jatropha had a threshold value of 5 dS m−1 implying that jatropha responds sensitive to external salt application in term of canopy development, conductance and CO2 assimilation rate. The rapid decrease of canopy conductance indicates that jatropha is effectively protecting leaves from massive Na import into leaves over short time periods. Our data indicate that use of wastewater in (semi-)arid areas should be carefully considered if high productivity is the key of plantation management.

Physiological relationships of the early posthatch performance of broilers to their embryo and eggshell characteristics

Relationships between physiological parameters of early posthatch chicks with their corresponding egg and embryo parameters were examined in progeny of young broiler breeders. Four hundred and 80 broiler hatching eggs that were obtained from a 29-wk-old Ross 308 breeder flock were incubated on 8 replicate tray levels of an incubator until hatch. Between 10.5 and 18.5 d of incubation, internal (T(emb)) and external (T(ext)) egg temperatures were recorded twice daily using temperature transponders. Beginning at 18.5 d, the eggs were individually monitored for hatch every 12 h. Average T(emb), T(ext), and average daily incubational egg weight loss (EWL) for the 10.5- to 18.5-d incubation period were used to calculate eggshell water vapor conductance (G(H2O)), specific G(H2O) (g(H2O); G(H2O) adjusted to 100 g of set egg weight basis), and a G(H2O) constant (K(H2O)) for each egg. Chicks were grown out for 10 d in pens of a single battery brooder. In each pen, on d 3 posthatch, carcasses, yolk sac, liver, and pipping muscle samples were collected from at least 2 chicks that hatched from eggs implanted with transponders for determination of their relative weights and moisture concentrations. Livers and pipping muscles were also analyzed for glucose, glycogen, fat, and protein concentrations. Yolk sac weight as a percentage of chick BW (YW) and its moisture concentration (YSM) were positively correlated with T(emb). Egg g(H2O) was positively correlated with chick carcass moisture concentration and its relative weight as a percentage of set egg weight, but it was negatively correlated with YW. The positive functional relationship between T(emb) and incubation length may be mediated via their common positive relationships to YSM. A negative correlation was observed between percentage EWL and relative BW on d 0 and 0.5 posthatch for chicks hatched from unimplanted eggs. The results suggest that a higher g(H2O) results in an increased metabolism of the broiler embryo, which subsequently increases growth and yolk sac absorption in broiler chicks through 3 d posthatch.

Quantification of excess water loss in plant canopies warmed with infrared heating

Here we investigate the extent to which infrared heating used to warm plant canopies in climate manipulation experiments increases transpiration. Concerns regarding the impact of the infrared heater technique on the water balance have been raised before, but a quantification is lacking. We calculate transpiration rates under infrared heaters and compare these with air warming at constant relative humidity. As infrared heating primarily warms the leaves and not the air, this method increases both the gradient and the conductance for water vapour. Stomatal conductance is determined both independently of vapour pressure differences and as a function thereof, while boundary layer conductance is calculated using several approaches. We argue that none of these approaches is fully accurate, and opt to present results as an interval in which the actual water loss is likely to be found. For typical conditions in a temperate climate, our results suggest a 12-15% increase in transpiration under infrared heaters for a 1°C warming. This effect decreases when stomatal conductance is allowed to vary with the vapour pressure difference. Importantly, the artefact is less of a concern when simulating heat waves. The higher atmospheric water demand underneath the heaters reflects naturally occurring increases of potential evapotranspiration during heat waves resulting from atmospheric feedback. While air warming encompasses no increases in transpiration, this fully depends on the ability to keep humidity constant, which in the case of greenhouses requires the presence of an air humidification system. As various artefacts have been associated with chamber experiments, we argue that manipulating climate in the field should be prioritized, while striving to limit confounding factors. The excess water loss underneath infrared heaters reported upon here could be compensated by increasing irrigation or applying newly developed techniques for increasing air humidity in the field.

Relationships of photosynthetic photon flux density, air temperature and humidity with tomato leaf diffusive conductance and temperature

The objective was to study the leaf temperature (LT) and leaf diffusive vapor conductance (gs) responses to temperature, humidity and incident flux density of photosynthetically active photons (PPFD) of tomato plants grown without water restriction in a plastic greenhouse in Santa Maria, RS, Brazil. The plants were grown in substrate and irrigated daily. The gs was measured using a steady-state null-balance porometer on the abaxial face of the leaves during the daytime. Both leaf surfaces were measured in one day. The PPFD and LT were measured using the porometer. Leaf temperature was determined using an infrared thermometer, and air temperature and humidity were measured using a thermohygrograph. The leaves on the upper layer of the plants had higher gs than the lower layer. The relationship between the gs and PPFD was different for the two layers in the plants. A consistent relationship between the gs and atmospheric water demand was observed only in the lower layer. The LT tended to be lower than the air temperature. The mean value for the gs was 2.88 times higher on the abaxial than adaxial leaf surface.

Flux-based ozone risk assessment for adult beech forests

Tropospheric ozone (O3) is a critical threat to forest ecosystems. A stomatal flux-based risk evaluation methodology at the leaf level was established recently in the context of the Convention on Long-Range Transboundary Air Pollution (LRTAP). This study demonstrates improvement and validation of the stomatal flux-effect approach for adult beech with results from the 8-year free-air O3 enrichment experiment at “Kranzberger Forst” (Germany). The risk assessment module of the SVAT model FO3REST, being under development for local scale O3-risk assessment of adult beech stands, was parameterized according to the LRTAP Convention’s Mapping Manual. Mean maximum stomatal conductance for water vapour of 245 mmol H2O m−2 PLA s−1, as suggested in the LRTAP Convention’s Mapping Manual for beech, was affirmed by assessment at “Kranzberger Forst”, resulting in 162 mmol O3 m−2 PLA s−1 upon recommended adjustment of the O3/water vapour diffusivity ratio to 0.663. Based on this ratio, a provisional corrected flux-effect function was deduced. Modelled Phytotoxic O3 Doses (POD 1) and potential O3-caused losses in biomass formation estimated with a site-specific stomatal conductance algorithm differed slightly only from estimates by the original LRTAP parameterisation. Analysis-derived POD 1 target value within the meaning of Article 2 of the European Council Directive 2008/50/EC of 10 mmol O3 m−2 corresponded to potential loss in biomass formation of about 10 % in ambient air relative to “pre-industrial” conditions. However, exceedance occurred by about a factor of two during the study period, indicating high risk at “Kranzberger Forst” under ambient air. Assessment for doubled O3 exposure indicated potential underestimation even of the O3 risk because modelled losses in biomass formation are in the lower range of the standard deviation of the observed ones.

Quantitative evaluation of the dispersion achievable using different preparation methods and DC electrical conductivity of vapor grown carbon nanofiber/epoxy composites

The aim of this work is to quantitatively analyze the dispersion achievable using different methods for the preparation of vapor grown carbon nanofiber-epoxy composites. Four different dispersion methods were used, differing in stress level intensity: blender mixing, capillary rheometry mixing, 3 roll milling and planetary centrifuge mixing. Furthermore, the relationship between dispersion and DC conductivity of the composites was evaluated. For the dispersion analysis, four nanofiber concentrations ranging from 0.1 to 3.0 wt.% were prepared for each method, while the DC measurements were performed for eight concentrations, ranging from 0.0 to 4.0 wt.%. The dispersion was analyzed by transmitted light optical microscopy and greyscale analysis, following a methodology previously established. The results show that as the VGCNF content increases the dispersion level decreases, as indicated by the increase of the variance of the corresponding greyscale histograms. The 3 roll-mill method produces the samples with the highest dispersion levels, whilst the samples from the remaining methods show large VGCNF agglomerates. The dispersion along the length of the samples was also estimated, indicating symmetric variation of dispersion from the center. The dispersion method also strongly influences the overall composite electrical response. No relationship was found between the electrical conductivity and the greyscale analysis achieved by the different methods. Thus, this method for the quantification of dispersion works well for length scales around 0.1 μm, but this is above the relevant scale that determines the electrical response.

Fertilization effects on the ecohydrology of a southern California annual grassland

Nitrogen limits leaf gas exchange, canopy development, and evapotranspiration in many ecosystems. In dryland ecosystems, it is unclear whether increased anthropogenic nitrogen inputs alter the widely recognized dominance of water and energy constraints on ecohydrology. We use observations from a factorial irrigation and fertilization experiment in a nitrogen‐limited southern California annual grassland to explore this hypothesis. Our analysis shows growing season soil moisture and canopy‐scale water vapor conductance are equivalent in control and fertilized plots. This consistency arises as fertilization‐induced increases in leaf area index (LAI) are offset by reduced leaf area‐based stomatal conductance,gs. We interpret this as evidence of a hydraulic feedback between LAI, plant water status, and gs, not commonly implemented in evapotranspiration models. These results support the notion that canopy physiology and structure are coordinated in water‐limited ecosystems to maintain a transpiration flux tightly controlled by hydraulic constraints in the soil‐vegetation‐atmosphere pathway.

Photosynthesis and sugar concentration are impaired by the defective active silicon uptake in rice plants infected with Bipolaris oryzae

The effect of soluble silicon (Si) on photosynthetic parameters and soluble sugar concentrations was determined in leaves of rice cv. Oochikara and mutant plants of Oochikara defective in active Si uptake [low silicon 1 (lsi1)]. Plants were grown in hydroponic culture amended with 0 (−Si) or 2 mm Si (+Si), under either low or high photon flux density (PFD) and with or without inoculation with Bipolaris oryzae, the causal agent of brown spot of rice. Leaf Si concentration increased by 141 and 435% in +Si cv. Oochikara and by 119 and 251% in +Si lsi1 mutant plants under high and low PFD, respectively, compared with −Si plants. Plant biomass accumulation was improved by Si regardless of PFD, especially plants for cv. Oochikara. Brown spot severity was highest in −Si plants for cv. Oochikara and lsi1 mutant plants under low PFD. In the presence of Si, disease severity in plants grown under both low and high PFD was reduced, except for lsi1 mutant plants under high PFD. Plant inoculation reduced the photosynthetic parameters measured regardless of plant material or Si supply. A decrease of net carbon assimilation rate (A) of inoculated plants under low PFD compared with non‐inoculated plants was associated with damage in the photosynthetic apparatus, except for +Si cv. Oochikara in which stomatal restriction [low water vapour conductance (gs)] contributed to A reduction. Under high PFD, damage to the photosynthetic apparatus of inoculated plants was the main reason for the reduction in A for +Si and −Si lsi1 mutant plants. In addition, for −Si cv. Oochikara, a reduction in gs contributed to reduced A. However, for +Si cv. Oochikara, gs was the limiting factor for A. Inoculated plants of +Si cv. Oochikara had higher A values than +Si lsi1 mutant plants, regardless of environmental conditions. Soluble sugars were not detected in leaf tissues of plants under low PFD. For high PFD, Si improved the hexose concentration in non‐inoculated plants at 144 h after inoculation (hai) for lsi1 mutant plants and from 96 hai onwards for cv. Oochikara compared with −Si plants. However, plant inoculation reduced hexose concentration compared with non‐inoculated plants, mainly in +Si plants, regardless of plant material. Sucrose concentration increased in leaves of cv. Oochikara in the presence of Si whether inoculated or not. For +Si lsi1 mutant plants, sucrose concentration increased only at 48 hai compared with −Si plants, whether inoculated or not. The results of this study show that a minimum Si concentration is needed in leaf tissues of rice plants to avoid the negative impact of B. oryzae infection on photosynthesis and sugar concentration. High leaf Si concentration resulted in an increased soluble sugar concentration and together, but in independent ways, soluble sugar and Si reduced brown spot severity of rice.

WATER VAPOR CONDUCTANCE OF THE LOWER CRETACEOUS DINOSAURIAN EGGS FROM SANAGASTA, LA RIOJA, ARGENTINA: PALEOBIOLOGICAL AND PALEOECOLOGICAL IMPLICATIONS FOR SOUTH AMERICAN FAVEOLOOLITHID AND MEGALOOLITHID EGGS

The water vapor conductance (GH2O) of the neosauropod eggs from the Lower Cretaceous Sanagasta nesting site in La Rioja Province, Argentina, was examined and compared with other Cretaceous Argentinean oological material. The 2900 mgH2O/day·Torr GH2O of the Sanagasta eggshells confirms an extremely moist nesting environment and supports field observations of dug-out nests in a geothermal setting. The observed thinning of the outer eggshell surface during incubation increases gas conductance and concomitantly decreases eggshell mechanical resistance during the late ontogenetic stages, thus facilitating embryonic development and hatching. The Sanagasta and Entre Rios Province faveoloolithid eggs display the highest and comparable GH2O values and share several morphological and diagenetic characters, indicating comparable nesting strategy in geothermal settings. However, the faveoloolithid Yaminue and La Pampa Province specimens cluster together with lower GH2O values closer to the megaloolithid eggs. The GH2O of the megaloolithid egg Megaloolithus patagonicus was reconsidered and new results are now congruent with other reported megaloolithid GH2O values. Additionally, we hypothesize that Y-shaped pore canals of M. patagonicus, which upper sections reach only the top third or half eggshell thickness and, a wider section in the middle would not compromise the overall egg mechanical resistance like vertical pores connecting directly the outer to the inner eggshell surfaces. Such pore spatial arrangement and geometry would enhance, as the eggshell thins during incubation, a greater GH2O, GO2 and GCO2 and facilitate embryonic development in high moisture nesting contents. Overall, data suggests that neosauropod nesting and brooding behaviors were dependent on elevated moisture nesting environments.

Determination of embryonic temperature profiles and eggshell water vapor conductance constants in incubating Ross × Ross 708 broiler hatching eggs using temperature transponders ,

The comprehensive profiles of the internal and external temperatures of embryonated Ross × Ross 708 broiler hatching eggs during incubation were determined using temperature transponders, and eggshell water vapor conductance (G(H2O)), specific G(H2O) (g(H2O); G(H2O) adjusted to a 100 g set egg weight basis), and G(H2O) constants (K(H2O)) were calculated. On each of 8 replicate tray levels of an incubator, 2 nonembryonated and 4 embryonated eggs were each implanted with a transponder on d 10.5 of incubation for the determination of internal (air cell) temperatures of nonembryonated (T(nem)) and embryonated (T(emb)) eggs, respectively. In addition, 2 water-filled vials, each containing a transponder, were used on each tray level for the determination of the external microenvironment temperatures (T(ext)) of the embryonated and nonembryonated eggs. Between 10.5 and 18 d of incubation, incubator data logger temperatures were determined every 5 min; and incubator dry bulb temperature, T(ext), T(nem), T(emb), and the difference between T(emb) and T(nem) (T) were determined every 12 h. Over the days of incubation, regression coefficients for T(emb) and T were positive, whereas the regression coefficient for T(nem) was negative. There was a significant day of incubation × type of temperature measurement (T(ext), T(nem), and T(emb)) interaction for temperature. Between 13 and 18 d of incubation, mean values of T(emb) readings that were recorded every 12 h were consistently higher than those of T(ext) and T(nem), indicating the importance of air cell transponder implantation for the efficient estimation of broiler embryo temperature. Furthermore, mean values of the percentage of daily incubational egg weight loss, G(H2O), g(H2O), and K(H2O) of the embryonated eggs were 0.54 ± 0.019%, 14.4 ± 0.56 mg of H₂O/d per Torr, 25.0 ± 0.96 mg of H₂O/d per Torr per 100 g, and 5.20 ± 0.205, respectively. The results suggest that transponders may be implanted in the air cells of broiler hatching eggs to detect incubational variations in T(emb) and to subsequently calculate G(H2O), g(H2O), and K(H2O).

A Review of the Relationship between Eggshell Colour and Water Vapour Conductance

This review brings together the available literature that examines the effect of variations in pigmentation on the water vapour conductance of avian eggshells. Pheasant and Houbara bustard eggs provide some evidence that shell abnormalities can impact upon colour and water vapour conductance. By contrast, data from wild birds suggest that neither the degree of maculation or intensity of background colour impact upon conductance. Those studies that purport to show variation in rates of water loss in eggs with different degrees of pigmentation may have been confounded by variation in natural nesting conditions. This emerging field of research remains very much in its infancy.

The role of disorder on the AC and DC electrical conductivity of vapour grown carbon nanofibre/epoxy composites

Four dispersion methods were used for the preparation of vapour grown carbon nanofibre (VGCNF)/epoxy composites. It is shown that each method induces certain levels of VGCNF dispersion and distribution within the matrix, and that these have a strong influence on the composite electrical properties. A homogenous VGCNF dispersion does not necessarily imply higher electrical conductivity. In fact, it is concluded that the presence of well distributed clusters, rather than a fine dispersion, is more important for achieving larger conductivities for a given VGCNF concentration. It is also found that the conductivity can be described by a weak disorder regime.

Effect of morphology on water sorption in cellular solid foods. Part II: Sorption in cereal crackers

Experimental dynamical moisture profiles of crackers with a fine and coarse morphology are successfully predicted using a pore scale network model. Experimental profiles are obtained using a single point imaging (SPI) NMR technique that enables 3D mapping of the moisture content of relatively immobile water at low water activity.The relative vapor conductivity trough the structure is 33% and 64% for the fine and coarse structured crackers, respectively. It can be argued that this is due to their difference in cell connectivity and not directly related to their difference in average cell diameter (0.33 and 0.75mm, respectively). It was found that the retarded local sorption dynamics of the solid matrix has a noticeable influence on the moisture profiles that arise in the first hours. This is crucial for the moisture sorption dynamics of sub centimeter size samples, for which there is a distinct non-equilibrium between the vapor and the sorbed water phase. The local sorption at low water activity is a factor 3 faster for the fine structure cracker compared to the coarse one. This is due to their differences in average lamellae thickness (54 and 93μm, respectively).However, for the description of the overall moisture sorption dynamics of the few cm thick samples, on a time scale of days, it valid to assume local equilibrium and to use an effective diffusivity model. The relative vapor conductivity together with the porosity and the derivative of the sorption isotherm determines the effective moisture diffusivity for these open structures, which is a factor 3 lower for the fine structured cracker compared to the coarse one. The single sided moisture sorption in the 2.5 thick cracker samples is not even completed after 5days, mainly because at higher water content (near 20%) there is very little gradient in relative humidity to drive the vapor transport. This is reflected in the predicted effective moisture diffusivities which for the coarse cracker decrease from 16×10−9m/s2 (at 1% MC, 16% aw) to 7.6×10−10m/s2 (at 20% MC, 86% aw).

Effect of morphology on water sorption in cellular solid foods. Part I: Pore scale network model

A pore scale network model is developed to predict the dynamics of moisture diffusion into complex cellular solid foods like bread, crackers, and cereals. The morphological characteristics of the sample, including the characteristics of each cellular void and the open pore connections between them are determined from X-ray micro-tomography (XRT) data by means of 3D image analysis techniques. The 3D network allows to simulate the water vapor transport between the air cells through the open pores and the local sorption kinetics in the lamellae that separate them. In this way realistic moisture ingress profiles can be simulated in complex morphologies without need of unknown effective parameters. It is shown that the fine structure related transport characteristics embedded in the cell discretized network can be volume averaged to obtain a steady state relative vapor conductivity and a quasi-steady-state sorption time constant. These essential morphology related parameters can be used for an equivalent continuous two-equation description for a homogeneous product.

Speckles of cryptic black‐headed gull eggs show no mechanical or conductance structural function

The structural-function hypothesis provides an alternative to signalling-based predictions to explain the remarkable diversity observed in avian eggshell colour. According to the hypothesis, protoporphyrin, the common pigment of visible speckles, lubricates and thus strengthens the shell and simultaneously moderates gas transfer across it. Correlational evidence for the structural-function hypothesis in form of a coincidence of both shell thinning and reduced evaporation with eggshell speckles comes from a restricted set of species with limited calcium supply or little nest predation and no need for camouflage of the eggs. Here, we investigate whether protoporphyrin-based pigmentation similarly affects a species with cryptically marked eggs and ample dietary calcium, the black-headed gull, Larus ridibundus. Although shell thinning of speckles occurred, this effect was minimal compared with thinning through embryonic growth. Furthermore, speckled and plain areas of the shell did not differ in water vapour conductance through the shell. We conclude that protoporphyrin speckling does not fulfil a structural function in gull eggs. Instead, during shell formation where the protoporphyrin of speckles is deposited in place of calcite it could inflict a structural cost. We propose that the mechanical and water vapour conductance functions of shell speckling need to be evaluated as separate hypotheses and that both functions could, in fact, negatively affect each other.

Use of implantable temperature transponders for the determination of air cell temperature, eggshell water vapor conductance, and their functional relationships in embryonated broiler hatching eggs ,

Broiler hatching eggs obtained from a 29-wk-old Ross 308 breeder flock were weighed and set on 8 tray levels (60 eggs/level) of a single incubator. On d 10.5 of incubation, the eggs were weighed, and temperature transponders were implanted in the air cells of 4 randomly selected embryonated eggs per tray level for determination of internal egg temperature (IT). Two water-filled vials per tray level containing transponders were also placed within 5 cm of the implanted eggs for determination of external egg temperature (ET). Between 10.5 and 18.5 d of incubation, ET and IT were recorded every 12 h. Egg weights and embryo survival were determined on 10.5 and 18.5 d of incubation and were used for the calculation of average daily incubational weight loss of embryonated eggs (EWL) and average daily percentage of EWL. Approximately 75% (24 out of 32) of the embryos in the implanted eggs survived through d 18.5 of incubation. Mean ET and IT were used to calculate the water vapor pressure gradient across the eggshell, which was subsequently used with EWL to calculate eggshell water vapor conductance (G(H2O)) and specific G(H2O) (g(H2O); G(H2O) adjusted to a 100-g set egg weight basis). Mean percentage of EWL, ET, IT, G(H2O), and g(H2O) for the 10.5- to 18.5-d incubation period were 0.546 ± 0.02%, 37.1 ± 0.03°C, 37.8 ± 0.09°C, 13.9 ± 0.47 mg of H(2)O/d per Torr, and 24.5 ± 0.75 mg of H(2)O/d per Torr per 100 g, respectively. It was concluded that temperature transponders may be successfully implanted in the air cells of broiler hatching eggs to determine ET, IT, G(H2O), and g(H2O) in Ross × Ross 308 broiler hatching eggs. Nevertheless, increased embryo survivability by further improving the implantation procedure may increase the practicality of temperature transponder use in commercial settings.