Continuous Airflow Research Articles

Urea coated with oxidized charcoal reduces ammonia volatilization

Urea is the most consumed nitrogen fertilizer in the world. However, its agronomic and economic efficiency is reduced by the volatilization of NH3, which can reach 78 % of the applied nitrogen. The coating of urea granules with acidic compounds obtained by charcoal oxidation has the potential to reduce the volatilization, due to the acidic character, the high buffering capacity and CEC. This work aimed to evaluate the effect of HNO3-oxidized carbon on the control of NH3 volatilization. These compounds were obtained by oxidation of Eucalyptus grandis charcoal, produced at charring temperatures of 350 and 450 ºC, with 4.5 mol L-1 HNO3. The charcoal was oxidized by solubilization in acidic or alkaline medium, similar to the procedure of soil organic matter fractionation (CHox350 and CHox450). CHox was characterized by C, H, O, N contents and their respective atomic relations, by the ratio E4 (absorbance 465 nm) by E6 (absorbance 665 nm), and by active acidity and total acidity (CEC). The inhibitory effect of CHox on the urease activity of Canavalia ensiformis was assessed in vitro. The NH3 volatilization from urea was evaluated with and without coating of oxidized charcoal (U-CHox350 or U-CHox450) in a closed system with continuous air flow. The pH of both CHox was near 2.0, but the total acidity of CHox350 was higher, 72 % of which was attributed to carboxylic groups. The variation in the ionization constants of CHox350 was also greater. The low E4/E6 ratios characterize the high stability of the compounds in CHox. CHox did not inhibit the urease activity in vitro, although the maximum volatilization peak from U-CHox450 and U-CHox350 occurred 24 h after that observed for uncoated urea. The lowest volatilization rate was observed for U-CHox350 as well as a 43 % lower total amount of NH3 volatilized than from uncoated urea.

Modification of spontaneous activity patterns in the malaria vector Anopheles gambiae sensu stricto when presented with host‐associated stimuli

Anopheles gambiae sensu stricto Giles (Diptera: Culicidae) is the main malaria vector in sub‐Saharan Africa. Mated females show a circadian rhythm of spontaneous activity under constant environmental conditions that extends across the scotophase (subjective night). The effect of host‐associated cues [i.e. human foot odour supplemented with carbon dioxide (CO2)] on this nocturnal activity pattern is studied in laboratory‐reared A. gambiae s.s. M molecular form. Sixteen mated females (5–10 days old) are held in individual chambers (diameter 3.5 cm, length 4.5 cm) in a wind‐tunnel with a continuous flow (8.0 cm s−1) of clean air. At the onset of hours 3, 6 and 10 of the scotophase, their behaviour is recorded on video for 15 min in clean moving air and then for the next 15 min, with a specific treatment present in the clean airstream: (i) constant CO2 (4.8%) plus human odour; (ii) pulsed CO2 (5 s of every 30 s) plus human odour or (iii) control (clean air). Activities of individual mosquitoes are scored by direct observation of the video records for the incidents of ‘resting’, ‘walking’, ‘jumping’ and ‘flying’ in each of the 15‐min observation periods. There is a significant interaction between hour and treatment on mean changes in female activity level (P = 0.00004). Constant treatment increases the level of activity of A. gambiae females significantly, although only in hour 3 of the scotophase (P < 0.01), whereas pulsed and control treatments show no significant effect throughout the scotophase. Patterns of spontaneous activity in individual A. gambiae females thus appear to be modulated by host‐associated cues, resulting in a more active phase early in the night than might be expected from records of spontaneous activity under constant environmental conditions. Possible ecological and experimental implications of such an increase in activity are discussed in relation to host‐seeking behaviour.

Changes in color, antioxidant, and free radical scavenging enzyme activity of mushrooms under high oxygen modified atmospheres

The effects of high oxygen concentration (80% O2) on color, antioxidant enzyme and free radical scavenging activity of mushrooms (Agaricus bisporus) were investigated. High oxygen modified atmosphere chambers were designed. Mushrooms (A. bisporus) were held at 2°C for 12d in modified atmosphere chambers, linked by separate lines to continuous flow (1.67mLs−1) of humidified air (control) and 80% O2 (balanceN2). Browning of mushroom flesh and surface exposed to 80% O2 was prevented and the expected increase in membrane permeability and lipid peroxidation was delayed. Compared to the control treatment, high oxygen significantly inhibited the reactive oxygen species (ROS) such as O2− and H2O2. The corresponding oxygen radical scavenging enzyme activities including SOD, CAT and POD in 80% O2 were also higher than those in the control (P<0.05). Higher antioxidant activity was found in high oxygen treated mushrooms. The treatment with 80% O2 could be used in modified atmosphere of mushrooms to avoid browning, which was due to enhanced antioxidant and free radical scavenging enzyme activity.

Microflotation performance for algal separation

The performance of microflotation, dispersed air flotation with microbubble clouds with bubble size about 50 µm, for algae separation using fluidic oscillation for microbubble generation is investigated. This fluidic oscillator converts continuous air supply into oscillatory flow with a regular frequency to generate bubbles of the scale of the exit pore. Bubble characterization results showed that average bubble size generated under oscillatory air flow state was 86 µm, approximately twice the size of the diffuser pore size of 38 µm. In contrast, continuous air flow at the same rate through the same diffusers yielded an average bubble size of 1,059 µm, 28 times larger than the pore size. Following microbubble generation, the separation of algal cells under fluidic oscillator generated microbubbles was investigated by varying metallic coagulant types, concentration and pH. Best performances were recorded at the highest coagulant dose (150 mg/L) applied under acidic conditions (pH 5). Amongst the three metallic coagulants studied, ferric chloride yielded the overall best result of 99.2% under the optimum conditions followed closely by ferric sulfate (98.1%) and aluminum sulfate with 95.2%. This compares well with conventional dissolved air flotation (DAF) benchmarks, but has a highly turbulent flow, whereas microflotation is laminar with several orders of magnitude lower energy density.

Visual cues collimate the trajectories of almond moth Cadra cautella males flying in wind and still air within a wind‐formed plume of pheromone

Male Cadra cautella (Walker) moths are videotaped in three dimensions in a 3‐m long wind tunnel as they fly within a 65‐cm wide plume of pheromone. Moths are presented two floor patterns, either ‘aligned’, a 25‐cm wide ‘trail’ of solid red circles along the tunnel's midline, or ‘offset’, in which the trail veers 25 cm to the left at the tunnel's midpoint. These visual patterns are presented either in a continuous airflow or airflow that is stopped before moths reach the tunnel's halfway point. Moths fly relatively straight paths over the aligned pattern in still air after the wind is stopped. With the offset pattern in wind and when the wind is stopped, moths swerve towards the offset pattern before again progressing along the plume. Prominent visual cues appear to ‘collimate’ (i.e. align with a directional cue) the moth's course as long as the moth remains in contact with pheromone. In wind, these moths appear to favour trajectories that enhance visual feedback, even if the path taken is not directly upwind. During wind lulls, this manoeuvre may enable moths to continue progress towards calling females along a visually set course. The centring of trajectory over prominent visual cues suggests that these moths favour a route that enhances visual feedback.

Performance Evaluation of Quality Drying in a Natural Convection Grain Dryer

In the villages of developing countries, use of electricity or petroleum fuel is expensive for drying the agricultural products. In the current scenario, drying through “natural convection grain dryer” is an important alternative. This paper proposes the development and evaluation of the natural convection grain dryer in drying performance of paddy. The proposed system is capable of generating an adequate and continuous flow of hot air with range of 60-70 degree centigrade. Paddy was successfully dried from 33% moisture content to 14% (w.b). Woodchips (biomass) were burnt to heat the incoming air in the dryer. Experiments were conducted with fixed amount of sensible heat storage material with varying the amount of latent heat storage material. Increase in the latent heat of storage material indicates the improvement in standard drying temperature, time and enhancement in amount of paddy dried. Re-firing further enhances the duration of optimum temperature range for quality drying.

HEATING AND VENTILATION

The author discusses the basic principles concerned in arriving at a reasonable atmospheric environment in museums and art galleries. Relative humidity must be maintained within reasonable limits. Rapid fluctuations in relative humidity must be prevented and continuous air flow around objects must be ensured. Although the general museum climate is about 50% R.H. at 65 degrees F, the type of object to be protected must be borne in mind; e.g., sweating glass must be kept below 42% R.H. Excessive dryness causes embrittlement, damage to marquetry and slackening of canvas. Excessive wetness causes mold growth, weakening of adhesives, staining, and encourages metallic corrosion. Rapid changes in humidity cause warping of wood, flaking paint and activation of soluble salts. Apart from complete automatic air conditioning which is expensive, there are a number of self-contained standard units. Self-contained unit conditioners control the temperature and humidity of fresh air let in from outside. Store units condition and circulate air in the room. Unit heaters and coolers circulate air, maintain uniform temperature and eliminate temperature gradients. Unit humidifiers and dehumidifiers provide water vapour or take it up. In storerooms an electrically heated urn containing water may be used (3 gal. Per 25,000 cu. Ft. Of air space) with a slow moving horizontal electric fan. A small room built into a larger room provides some protection against variation in conditions. Carpets and hangings help maintain a good climate for similar reasons. Continuous recording of the relative humidity, and periodic checks with a sling psychrometer or whirling hygrometer are necessary.

É possível validar estatisticamente um dispositivo experimental com 10 ratos, de baixo custo, para pesquisa em tabagismo passivo?

INTRODUCAO: Pessoas nao tabagistas que convivem com a fumaca produzida por fumantes podem sofrer os danos causados por esta exposicao. Diversos estudos experimentais demonstraram os efeitos negativos do tabagismo, tanto ativo quanto passivo. A fim de simular a exposicao passiva a fumaca do cigarro em ratos, foi desenvolvido e validado um aparato (Braga-Gazzalle) simples, barato e de facil manutencao no Laboratorio de Habilidades Medicas e Pesquisa Cirurgica - PUCRS. METODO: O sistema de inalacao consiste em uma caixa de polipropileno de 40x33x17 cm, dividida em dois compartimentos por uma tela de metal: o maior para ratos e o menor para cigarros. Um ventilador gera um fluxo interno continuo de ar para que a fumaca produzida pela ponta acesa alcance os animais. Apos aprovacao no Comite de Etica, 5 ratos (Grupo A) foram expostos durante 2 horas diarias a fumaca, comparado ao grupo controle de 5 ratos (Grupo B). Apos exposicao de 4 semanas, dosou-se a carboxihemoglobina (CoHb) serica. Os animais foram entao sacrificados. A analise estatistica utilizada foi o teste t-Student, com 5% de significância. RESULTADOS: No Grupo A, a media dos percentuais de CoHb serica foi de 11,52 ± 4,40%, enquanto no Grupo B a media encontrada foi de 0,3 ± 0,2%. Os niveis de carboxihemoglobina observados no Grupo A foram muito maiores do que no Grupo B (p < 0,001). CONCLUSOES: O modelo experimental desenvolvido pelos autores provou que expoe adequadamente os animais a fumaca passiva. O aparato se mostrou confiavel, de facil manutencao e, sobretudo, de baixo custo operacional.

Effect of longwall face advance rate on spontaneous heating process in the gob area – CFD modelling

A commercial CFD software programme, FLUENT, was used to study the oxidation process of coal in the mined-out longwall (gob) area. A three-dimensional, single-phasemodel with a continuously advancing longwall face has been developed. For the model, the gob longwall area was designed on the basis of the actual longwall panel operating in the Ostrava-Karviná Coal Mines (OKD, Czech Republic). The behaviour of the coal to oxygen was modelled using the results arising mainly from the former laboratory-scale experiments with Czech bituminous coals. Basically, the technique of pulse flow calorimetry and measurements at a continuous airflow reactor were applied during the laboratory investigations. In the contribution, the main focus was to understand the effect of the longwall face advancing speed on the oxidation heat production as well as evolution of the gases in the gob area. Simultaneously, the effect of coal crushing in the mined-out area on the spontaneous heating process was examined.Numerical simulations confirmed the existence of a “favourable” zone for the onset and development of the spontaneous heating process in the gob area. The location and the maximal temperature reached in the “favourable” zone were found to be significantly affected by the advancing rate of the coalface. The slower the advancing rate is, the higher the maximal temperature and smaller the depth of the “favourable” zone in the gob area are. When the rate drops to a certain “critical” value, spontaneous heating turns to flammable combustion of the coal. The value of the “critical” advancing rate was confirmed to increase if the grain size of the coal left in the gob decreases. Numerical examinations of carbon monoxide concentrations then proved that small incidents of spontaneous heating could occur in the gob area that need not be detected in the airflow of the longwall tail gate.

Association between increased DNA mutational frequency and thermal inactivation of aerosolized Bacillus spores exposed to dry heat.

Inactivation of viable bioaerosol particles, especially stress-resistant microorganisms, has important implications for biodefense and air quality control. It has earlier been shown that the loss of viability of bacterial endospores due to exposure to dry heat is associated with mutational damage. Previous studies, however, used non-aerosolized spores, long exposure times, and moderately elevated temperatures. This study was designed to investigate the mechanism of inactivation of aerosolized Bacillus endospores exposed to high temperatures for sub-second time periods. Bioaerosol was tested in a continuous air flow chamber under two flow rates, 18 L/min and 36 L/min. The chamber had a cylindrical electric heating element installed along its axis. The estimated characteristic exposure temperature (T exposure ) ranged from 164°C to 277°C (with an uncertainty of 21-26°C). To quantify mutational frequency, spores were cultivated after dry heat exposure on tryptic-soy agar and on antibiotic nalidixic acid media. Increases in the exposure temperature caused viability loss and increase in mutational frequency of the spore DNA. Significant association was found between the inactivation factor and the mutational frequency ratio (heat exposed versus non-exposed) with R2 of 0.985 for both flow rates combined. The results suggest that mutational damage is involved in the causal chain of events leading to inactivation of aerosolized endospores exposed to heat for sub-second time periods.

Air-Stream Drying of Paper

Airflow drying has originally been applied in printmaking and hand papermaking workshops in order to shorten drying times and maintaining planarity of paper. The technique was already suggested by R. Futernick in 1988 and was first introduced to paper conservation at the Western Regional Paper Conservation Laboratory in San Francisco. In this contribution, the physical basics of the drying process, including a simple drying stack prepared from corrugated board, are described. Drying is carried out in stacks of archival-quality corrugated cardboards and other paperboard materials under slight pressure. The stack of cardboards is equipped with a blower that provides a continuous airflow through the open channels of the card boards. The water is removed from the stacks by continuous evaporation through the moisture absorbing board until equilibrium with the ambient air is reached.

Skin effect in the heat and mass transfer model for sewage sludge drying

The thermal drying of sewage sludge was studied in the 30–65 °C temperature range with two types of sewage sludge, showing different behaviour in the formation of a skin during the drying process. Twenty-one runs were carried out at different temperatures and air flows in an apparatus that provided a continuous flow of air. Small sewage sludge spheres and cylindrical tablets were produced to study the kinetics. During each run, the variation of moisture content vs. operation time was monitored, and during some tests, the temperature inside the sample as well. A kinetic model was developed to correlate the experimental data, both moisture content and temperature, vs. time. The resulting kinetic parameters (mass transfer coefficient, heat transfer coefficient, skin effect parameter, diffusion coefficient and activation energy) are discussed with reference to correlations and kinetic parameters presented in the literature. In general, the model seemed to suitably reproduce the experimental moisture and temperature data. For some runs there were significant deviations between the experimental and calculated temperatures, which could be explained by an evaporation effect taking place at the surface of the thermocouple wire placed inside the sludge spheres. The kinetic parameters have been used for simulation of continuous dryers. Finally, an analysis of the influence of the different parameters on the drying process has been carried out in order to obtain a general model valid for different types of sewage sludges.

Study of CO 2 stability and electrochemical oxygen activation of mixed conductors with low thermal expansion coefficient based on the TbBaCo 3ZnO 7+ δ system

The influence of different application-oriented factors on the electrochemical activity and stability of TbBaCo 3ZnO 7+ δ when used as a solid oxide fuel cell cathode has been studied. Calcination at temperatures above 900 °C (e.g. 1000 °C) leads to a significant increase in the electrode polarization resistance. The effect of the sintering temperature of the TbBaCo 3ZnO 7+ δ cathode seems to be more important than the effect produced by the Tb substitution as observed when compared with 900 °C-sintered YBaCo 3ZnO 7+ δ ; and ErBaCo 3ZnO 7+ δ electrode performances. The presence of CO 2 in the air flow leads to an increase of roughly 10% in the polarization resistance for the whole studied temperature range (500–850 °C) while this effect is reversible. Analysis of the impedance spectroscopy measurements shows that the exchange rate constant ( k G from Gerischer element) is significantly affected by CO 2 at temperatures below 700 °C, while the diffusion coefficient related parameter is slightly influenced at low temperatures. Electrode degrades with a low constant rate of 1 mΩ cm 2 h −1 after 60 h. This cathode material exhibits high CO 2 tolerance, as shown by temperature programmed treatment under a continuous gas flow of air with 5% CO 2, and a relatively low thermal expansion coefficient.

Inactivation of Aerosolized Viruses in Continuous Air Flow with Axial Heating

Thermal inactivation of viruses has been studied in relevance to food sterilization, water purification, and other “non-aerosol” applications, in which heat treatment is applied for a relatively long time. No data are available on the inactivation of airborne viruses exposed to dry heat for a short time, although this is relevant to bio-defense and indoor air quality control. In this study, we investigated inactivation of aerosolized MS2 viruses in a continuous air flow chamber with axial heating resulted from exposures during ∼ 0.1–1 s. For an airborne virion, the characteristic exposure temperature, T e , was defined utilizing the air temperature profiles in the chamber. The tests were conducted at two air flow rates, Q, which allowed for establishing different thermal flow regimes and exposure time intervals. The experimentally determined inactivation factor, IF, was subjected to correction to account for the temperature profiles. At T e up to ∼ 90°C (Q = 18 L/min) and up to ∼ 140°C (Q = 36 L/min), the...

Aldol condensation products during photocatalytic oxidation of ethanol in a photoelectrochemical cell

Electric current was produced in a photoelectrochemical cell during photocatalytic oxidation of ethanol, which was used as a representative organic compound present in wastewater from biomass processing industries. Thus, the cell behaved as a PhotoFuelCell that consumed waste material to produce electricity. The cell consisted of two compartments separated by a silica frit. The anode electrode was a Fluorine-doped Tin Oxide transparent electrode bearing nanocrystalline titania Degussa P25, applied as a paste and calcined at 550°C. The cathode electrode was a carbon-cloth bearing Pt/Carbon-Black catalyst. The electrolyte was 1.0M NaOH. When 20%v. ethanol was added in the anode compartment, the cell gave 0.75mA/cm2 short-circuit current density (calculated over 12cm2 electrode area) and 1.1V open-circuit voltage. The anode compartment of the cell was operated under three different conditions: (1) under continuous air flow, i.e. oxygen-rich conditions; (2) under Ar flow, i.e. anaerobic conditions; and (3) exposed to ambient air but without any gas flow through the cell, i.e. oxygen-deficient, mass transfer-limited conditions. In the latter two cases, the oxidation of ethanol and its photo-oxidation products was incomplete and resulted in aldol condensation reactions that produced various aldehydes, some of them of high molecular weight and insoluble. It was concluded that in order to avoid such reactions, which impede mineralization process, measures should be taken for continuous oxygen supply and for optimal combination of the quantity of the photocatalyst and the concentration of the photodegradable substance. Thus only 1%v. ethanol can give 75% of the maximum current obtained in the presence of large ethanol concentration.

WE‐D‐204B‐04: Distribution of Lung Tissue Motion during Free Breathing

Purpose: To characterize and quantify free breathing lung tissue motion diction. Method and Materials: 50 patient data sets were acquired using a 4DCT protocol consisting of 25 ciné scans at abutting couch positions on a 16 slice scanner. The tidal volume of each scan was measured by simultaneously acquiring spirometry and an abdominal pneumatic bellows. Because of the natural variation in breathing patterns, we elected to develop the concept of a representative breath. The representative breath was defined by first dividing the breathing traces into individual breaths, from exhalation to exhalation. A linear breathing drift model was assumed and the drift removed for each breath. Breaths that exceeded one standard deviation in period and amplitude were removed from the analysis. A representative breath was defined as the average time from peak inhalation to a normalized tidal volume. Airflow was determined using a sliding polynomial fit to the representative breath profile. The trajectories were computed using an existing 5D lung tissue trajectory model: X = Xo+αngr+βf where α and β were previously determined. In order to characterize the motion patterns, the elongation of the trajectories were examined throughout the subject's lungs. Elongation was defined here by generating a bounding box with one side parallel to the α vector and the box lying in the plane defined by the α and β vectors. Results: The representative breath process provided an excellent method for defining an average breath that had continuous tidal volume and airflow characteristics when the breath was continuously repeated. The elongation varied smoothly throughout the lungs. Left lung elongation was 0.10±0.05 and right lung elongation was 0.09±0.04 in a central coronal lung slice. Conclusion: As expected, motion elongations were relatively small indicating for many tumor sites, hysteresis motion could be ignored. This work supported in part by NIHR01CA116712 and NIHR01CA96679.

Dispersal and Movement Behavior of Neonate European Corn Borer (Lepidoptera: Crambidae) on Non-Bt and Transgenic Bt Corn

Neonate movement and dispersal behavior of the European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), were investigated under controlled conditions on Bacillus thuringiensis (Bt) and non-Bt corn, Zea mays L., to assess plant abandonment, dispersal from their natal plant, and silking behavior after Bt and non-Bt preexposure. With continuous airflow, neonates on a Bt corn plant for 24 h abandoned that plant 1.78 times more frequently than neonates on a non-Bt corn plant. Indirect evidence indicated that at least one third of the neonates were capable of ballooning within 24 h. In the greenhouse, some neonates were recovered after 24 h from plants 76 and 152 cm away that likely ballooned from their natal plant. After 1 h of preexposure on a Bt corn leaf, neonates placed on a new corn leaf and observed for 10 min began silking off of a new Bt leaf significantly sooner than a new non-Bt leaf. Results suggest that neonates are unable to detect Bt in the corn within 10 min but that they can detect it within the first hour.

Thermal characteristics in round tube fitted with serrated twisted tape

Abstract The article presents an investigation of the effect of twisted tape with serrated-edge insert on heat transfer and pressure loss behaviors in a constant heat-fluxed tube. In the experiments, the serrated twisted tape ( STT ) was inserted into the entire test tube with a constant twist ratio in order to generate a continuous swirling airflow. Two geometry parameters of the STT to be considered in the present work are the serration width ratio and the serration depth ratio. The measurements have been conducted for the airflow rate based on Reynolds numbers in the turbulent regime from 4000 to 20,000. The experimental results of the STT inserted tube are compared with those of the plain tube fitted with typical twisted tape ( TT ). The results show that the heat transfer rate in terms of Nusselt number, Nu increases with the rise in the depth ratio but decreases with raising the width ratio. The heat transfer rate is up to 72.2% and 27% relative to the plain tube and the TT inserted tube, respectively. The use of the STT leads to higher heat transfer rate and friction factor than that of the TT for all cases. The thermal performance factor of the STT tube under constant pumping power is evaluated and found to be above unity indicating that using the STT tube is advantageous over the TT tube or the plain tube. In addition, the empirical correlations developed by relating the serration width ratio, serration depth ratio and Reynolds number are determined.

Unidirectional Airflow in the Lungs of Alligators

The lungs of birds move air in only one direction during both inspiration and expiration through most of the tubular gas-exchanging bronchi (parabronchi), whereas in the lungs of mammals and presumably other vertebrates, air moves tidally into and out of terminal gas-exchange structures, which are cul-de-sacs. Unidirectional flow purportedly depends on bellowslike ventilation by air sacs and may have evolved to meet the high aerobic demands of sustained flight. Here, we show that air flows unidirectionally through parabronchi in the lungs of the American alligator, an amphibious ectotherm without air sacs, which suggests that this pattern dates back to the basal archosaurs of the Triassic and may have been present in their nondinosaur descendants (phytosaurs, aetosaurs, rauisuchians, crocodylomorphs, and pterosaurs) as well as in dinosaurs.

Methodology to Evaluate Oxidation Degradation of High-Density Polyethylene Corrugated Pipe Resin

A methodology is presented to evaluate the oxidative degradation of compression-molded samples made from high-density polyethylene corrugated pipe resin. The test samples contained 2.5 wt% of carbon black and an antioxidant (AO) package that consisted of 0.05% Irganox 1010 and 0.1% Irgafox 168. Samples were incubated in forced-air ovens at temperatures of 65°C, 75°C, and 85°C (149°F, 167°F, and 185°F) and in a water bath at 85°C (185°F). The amount of AOs in the incubated samples was measured by using both the oxidative induction time (OIT) test and the induction temperature (IT) test. It was found that the OIT test was much more sensitive than the IT test in assessing the AO depletion of incubated samples. For the evaluation of oxidation degradation, both melt index (MI) and tensile break elongation were used to detect changes in molecular weight and mechanical property, respectively. For air incubation, AO depletion rates obeyed a first-order reaction at all three temperatures, and the AOs underwent two simultaneous reactions according to the second-order reaction at the 85°C water incubation. At 85°C (185°F) air incubation, oxidation degradation was detected as reflected by a decrease in MI and tensile break elongation. The decrease of MI indicated an increase in the molecular weight due to the cross-linking of the polymer. According to the Arrhenius equation, the predicted lifetime of this particular AO package under continuous flow of air is 117 years at 23°C (73.4°F).