CO2 Gas Pressure Research Articles

Comparison of Pallet Cover Systems to Maintain Strawberry Fruit Quality During Transport

The efficacy of several proprietary plastic pallet cover systems to maintain strawberry (Fragaria ×ananassa) fruit quality during commercial shipment was determined. ‘Albion’ fruit were harvested from farms near Watsonville, CA. Fruit in vented plastic clamshells were palletized and forced-air cooled to 33–35 °F. Different cover systems (CO2 West, PEAKfresh, PrimePro, Tectrol) were placed over the pallets. Pads that released carbon dioxide (CO2) gas were placed inside the CO2 West cover. The Tectrol cover was sealed to the pallet base, a partial vacuum was applied, and pressurized CO2 gas was injected inside. The systems other than Tectrol remained open at the base. Six separate shipments of palletized fruit were transported in refrigerated (32–39 °F) truck trailers to distribution centers in either Florida or Georgia in 2.3–4.7 days. CO2 concentrations within pallets at the beginning and end of transport were highest (11% to 16%) in the sealed Tectrol system and relatively low (0.06% to 0.30%) in the open CO2 West, PEAKfresh, and PrimePro cover systems. Relative to noncovered control fruit, which lost 0.8% fresh weight during shipment, the pallet covers reduced the transport-related weight loss by 38% to 52%. The incidence of fruit decay was low (1.0% to 1.4%) after transport but increased substantially following a 2-day shelf life at 68 °F. However, fruit from the Tectrol pallets exhibited significantly less decay (36%) after shelf life than the CO2 West (39%), noncovered control (41%), PrimePro (42%), and PEAKfresh (43%) pallets. Fruit sensory quality was unaffected by the different pallet cover systems. Our findings show that transporting strawberries in the sealed Tectrol pallet cover system, in which CO2 concentrations were elevated to 11% to 16%, was most effective in complementing current low temperature management practices to maintain fruit quality.

Tu1579 Cryospray Ablation Using Pressurized Carbon Dioxide Gas for the Ablation of Barrett's Esophagus With Early Neoplasia

higher Charlson Comorbidity Score (5.0 vs 3.6, p 0.001). EMR was associated with a higher rate of any complication (36% vs 25%, p 0.05) due entirely to the development of stricture formation (36% vs 6%, p 0.0001). All strictures in the EMR group were successfully treated with a median of 1 endoscopic dilation. In the surgery group, 10 patients (4%) required re-operation, and 24 (10%) developed an anastomotic leak. 3 surgery patients (1%) died during hospitalization vs. 0 procedural deaths in the EMR group. Excluding those without at least HGD on final pathology, EMR patients were marginally more likely to have cancer found during follow-up than surgery patients (7% vs. 3%, p 0.25). In the EMR group, all recurrent HGD or cancer occurred within the first 18 months of follow-up (Figure 1). 6 EMR patients (8%) crossed over to surgery, and 13 (17%) ultimately also received radiofrequency ablation. There were 0 cancer deaths in the EMR group and 2 (1%) in the surgery group. Excluding patients without at least HGD, EMR was marginally associated with better survival than surgery (Hazard Ratio 0.80, 95% confidence interval 0.16, 3.9), adjusting for age and comorbidities (Figure 2). Conclusion: At a center with expertise in both procedures, we did not find that EMR was associated with worse survival or recurrence rates than esophagectomy for HGD or IMC. Although EMR had more complications, these were all treated endoscopically and there were no procedure related deaths. To our knowledge, this is the largest comparison of EMR to surgery, yet the analysis is still limited by sample size. EMR is a viable option for treatment of Barrett’s esophagus with HGD or IMC if patients receive close surveillance for 2 years following completion of therapy. Tu1579 Cryospray Ablation Using Pressurized Carbon Dioxide Gas for the Ablation of Barrett’s Esophagus With Early Neoplasia Romy E. Verbeek*, Frank P. Vleggaar, Fiebo J. Ten Kate, Jantine W. Van Baal, Peter D. Siersema Gastroenterology and Hepatology, University Medical Center Utrecht, Utrecht, Netherlands; Pathology, University Medical Center Utrecht, Utrecht, Netherlands Background: Cryotherapy is a relatively novel ablation modality for the endoscopic ablation of Barrett’s esophagus (BE). Data on the use of pressurized carbon dioxide (CO2) gas for cryoablation are scarce.AIM: To determine efficacy and safety of cryospray ablation using pressurized CO2 gas (Polar wand, GI supply) in the treatment of BE with early neoplasia. Methods: In this prospective single center study, we aimed to include 30 patients with BE and early neoplasia. Visible neoplastic lesions were treated with endoscopic mucosal resection (EMR). Residual BE mucosa was treated with cryospray ablation which was performed every 4 weeks until the complete BE segment was eliminated or up to 7 treatment sessions. If no reduction of the BE segment was observed after 2 subsequent treatment sessions, cryoablation was terminated. Cryospray treatments consisted of 6 applications with a CO2 catheter on 2-3 cm hemi circumferential BE during 20 seconds, with active suctioning of the stomach between applications. Biopsies of BE and neo-squamous epithelium were obtained in 4-quadrants every 1-2 cm prior to the 1st, 4th and 7th treatment and at 3 and 6 months post-treatment using a large capacity forceps. Patients were contacted at day 1 and 4 post-treatment to evaluate the level of discomfort. Interim analysis was scheduled after the inclusion of 10 patients for insufficient clinical effect, defined as complete eradication of intestinal metaplasia at 3 months follow-up in less than 50% of patients. Results: Interim analysis showed insufficient effect of cryoablation, which resulted in termination of the study. In total, 7 patients with intramucosal carcinoma (IMC) and 3 with high-grade dysplasia (HGD) were included. Prior EMR was performed in 9 patients. Precryoablation diagnoses were intestinal metaplasia (IM; n 4), low-grade dysplasia (LGD; n 5) and high-grade dysplasia (HGD; n 1).,A median of 3.0 (IQR1.8-4.8) cryoablation sessions were performed. At 6 months follow-up, complete eradication of dysplasia was observed in 50% (3/6) of the patients and complete eradication of IM in 20% (2/10). One patient progressed to IMC. A nonsignificant reduction of the BE length was observed (5.0 (IQR1.8-7.3) vs. 2.5 (IQR0.9-6.3) cm, p 0.08). No buried BE glands were detected in the ablated segments. In 1 patient, gastric perforation occurred after the first treatment as a result of gastric distention caused by CO2 gas. No further cryoablation was applied in this patient. Apart from a superficial esophageal laceration in another patient, cryospray treatments were well tolerated. Conclusion: After a short learning curve, cryoablation using CO2 gas is a safe and well tolerated treatment modality. However, in our experience, the efficacy of CO2 cryoablation combined with EMR for nodular lesions is disappointing for the treatment of residual BE and BE associated dysplasia.

Gasification and Reduction Behavior of Iron Ore-Carbon Composite under High Pressure

Iron oxide-carbon composites have a potential to play a significant role in mitigating CO2 emission from the ironmaking process. However, efficiency of gasification and reduction of iron ore-carbon composite seem to be limited under the condition of blast furnace. In this study, effect of pressure on the gasification and reduction of the composite was evaluated. Hematite reagent and ore powders were mixed with graphite powder to make composite samples. They were heated up to different target temperatures at a heating rate of 0.167°C/s under different pressures. Weight loss fraction was obtained by the difference between sample masses before and after reduction. Gasification temperature decreased and weight loss fraction at the target temperature increased with an increase in pressure. Further, molar ratio of CO to (CO+CO2) in the outlet gas decreased with increasing pressure, after it reached the coexisting condition of wustite and metallic iron phases. These results show that an increase in pressure leads to increase in the reaction rate of indirect reduction. Further, this can be attributed to an increase in the partial pressure of CO gas and the prevention of gasification reaction.

Nano Gas Cluster Dry Cleaning for Damage Free Particle Removal

CO2 gas cluster cleaning process for nano particles removal without pattern damage was investigated. Gas cluster cleaning process was performed for generating the nano-sized gas cluster in the vacuum chamber. When pressurized CO2 gas was passed through the convergence-divergence (C-D) nozzle, the high speed and high energy gas clusters were generated. The cleaning force of CO2 gas cluster is related to flow rate of the gas and gap distance between the nozzle and substrate. In our studies, the optimum gas flow rate and gap distance for nano-sized particles removal was found, respectively. Pattern damage tests of the poly-Si and a-Si pattern were also evaluated by SEM images. No pattern damages were observed at these optimum conditions.

Bilateral Axillo-Breast Approach Robotic Thyroidectomy

Bilateral axillo-breast approach (BABA) robotic thyroidectomy (RoT) has good postoperative and excellent cosmetic outcomes. This study aimed to describe the techniques for robotic BABA thyroidectomy in detail (see Videos, Supplemental Digital Content 1, http://links.lww.com/SLE/A45 and Supplemental Digital Content 2, http://links.lww.com/SLE/A46). Between 2008 and 2010, 704 patients underwent BABA RoT. The mean patient age was 38.9±9.1 years and the male-to-female ratio was 1:8.0. BABA RoT is an oncoplastic thyroid surgery using BABA and da Vinci robot system with low pressure of CO2 gas insufflations. The operation types were as follows: total thyroidectomy with or without neck dissection (n=556, 78.9%), subtotal thyroidectomy (n=67, 9.5%), lobectomy (n=73, 10.4%), and completion thyroidectomy (n=8, 1.1%). BABA RoT yields good postoperative outcomes. With excellent cosmetic outcomes, this technique may be a suitable alternative for patients with thyroid diseases.

Measurement of DT fusion and neutron-induced gamma-rays using gas Cherenkov Detector

A secondary gamma experiment was carried out using a Gas Cherenkov Detector (GCD) at the OMEGA laser facility. The primary experimental objective was to simulate neutron-induced secondary gamma production (n-γ) from a NIF implosion capsule, hohlraum, and thermo-mechanical package. The high-band width of the GCD enabled us to detect time delayed and Doppler broadened n-γ signals from five different puck materials (Si, SiO2, Al, Al2O3, Cu) placed near target chamber center. These measurements were used for MCNP & ITS ACCEPT code validation purposes. By a simple change of the GCD CO2 gas pressure the system can effectively eliminate signals induced by n-γ reactions and thereby allow quality measurements of DT fusion γ-rays that are produced at NIF (National Ignition Facility).

Adsorption technology for direct recovery of compressed, pure CO2 from a flue gas without pre-compression or pre-drying

The effects of the sorption and the regeneration temperatures on the performance of a novel rapid thermal swing chemisorption (RTSC) process (Lee and Sircar in AIChE J. 54:2293–2302, 2008) for removal and recovery of CO2 from an industrial flue gas without pre-compression, pre-drying, or pre-cooling of the gas were mathematically simulated. The process directly produced a nearly pure, compressed CO2 by-product stream which will facilitate its subsequent sequestration. Na2O promoted alumina was used as the CO2 selective chemisorbent, and the preferred temperatures were found to be, respectively, 150 and 450 °C for the sorption and regeneration steps of the process. The specific cyclic CO2 production capacity of the process and the pressure of the by-product CO2 gas were substantially increased over those previously achieved by using the sorption and regeneration temperature of, respectively, 200 and 500 °C (Lee and Sircar in AIChE J. 54:2293–2302, 2008). The net compressed CO2 recovery from the flue gas (∼92%) did not change. However, substantially different amounts of high and low pressure steam purges were necessary for comparable degree of desorption of CO2. A first pass estimation of the capital and the operating costs of the RTSC process was carried out for a relatively moderate size application (flue gas clean up and CO2 recovery from a ∼80 MW coal fired power plant). Both costs were substantially lower than those for a conventional absorption process using MEA as the CO2 solvent (Desideri and Paolucci in Energy Convers. Manag. 40:1899–1915, 1999).

ＣＯ２地中貯留への取組 収着熱測定および｀１´Ｈ‐ＮＭＲ横緩和時間測定による石炭‐ＣＯ２収着の解明

CO2 sorption on coal was estimated by two experiments, one is heat of sorption measurement and the other is 1H-NMR measurement. In the heat of sorption measurement, differential heat of sorption (qd) was compared with the calculated one. Measured qd was same value with calculated one at low pressure. It decreased gradually with pressure and became lower than the calculated one. Since it couldn't be explained by the theory based on physisorption, it is estimated that the coal-CO2 system could not be explained by only simple physisorption.In 1H-NMR measurement, spin-spin relaxation time (T2) and composition fractions of L1, L2 and G were measured. Composition fractions and T2 of L1 increased with CO2 gas pressure. Furthermore, the correlation was observed between volume increments and dissolution amount at over 10 atm. It indicates that part of CO2 sorption capacity was used to coal relaxation.

Fluidization and multiphase transport of particulate cometary material as an explanation of the smooth terrains and repetitive outbursts on 9P/Tempel 1

The Deep Impact mission discovered repetitive outbursts on Comet 9P/Tempel 1 and the presence of several smooth terrains on its surface. We present new measurements of the extent of the smooth terrains, the slopes along their centerlines, and the areas of their likely source regions. Our analysis of these features indicates that they are <700 orbits old and probably the result of an ongoing process. The implications of the recently found locations of the source regions of the repetitive outbursts are also analyzed. We propose that the origins of these phenomena are in the different regimes of fluidization and gas transport in a weakly bound particulate mixture of ice and dust above an assumed amorphous/crystalline H 2O phase change boundary where CO and/or CO 2 gas is released. The depth of this boundary is estimated to lie between 30 and 100 m below the surface. The smooth terrains are visualized as occurring about once every ∼70 orbits at random locations of the nucleus where a spurt in CO production occurs over a limited region of the phase change boundary. The weak (tensile strength ∼ 10 2 Pa ) crystalline and dust overburden is locally ruptured and fluidized by the CO gas pressure and is then extruded onto the surface at speeds of ∼0.003–0.03 m/s, well below the escape velocity of 1.3 m/s. Once on the surface a base pressure of only 2.5 Pa is required to ensure fluidization of the extruded material and it can remain fluidized for typically ∼20 h against diffusive loss of CO. As the material accelerates down the local topography it deflates due to diffusive gas loss. The flow becomes increasingly viscous until it is no longer fluidized at which point it quickly halts forming a terminal scarp. The mean speed of the laminar flow is estimated at 0.3 m/s for an emplacement time of ∼3 h. Topographic features on the flow >0.3 m in size should become fully relaxed during the emplacement time explaining the smooth texture seen in the images. In contrast, the repetitive outbursts require a gas-laden reservoir to have formed in the vicinity of the phase change boundary well below their preferred location. We visualize the outbursts to be the result of either spouting or bubble transport to the surface where the release of gas is diurnally modulated by either thermal stresses or H 2O sublimation back pressure. The source region for the i2 smooth terrain is found to coincide with an H 2O-ice rich area and we propose that the process of elutriation, i.e., the separation of different classes of particulates depending on their drag properties, occurs in the fluidized material as it flows up to and through the surface. In this way the material becomes enhanced in H 2O crystals relative to siliceous and carbonaceous particulates.

Synthesis and properties of polyurethane networks derived from new soybean oil‐based polyol and a bulky blocked polyisocyanate

AbstractBACKGROUND: Developing vegetable oil‐based polyols for polyurethane manufacturing is becoming highly desirable for both economic and environmental reasons. Most vegetable oils do not bear hydroxyls naturally. The objective of this work was to prepare a new soybean oil‐based polyol with high functionality of hydroxyl groups and built‐in (preformed) urethane bonds.RESULTS: A facile and improved method was developed for the transformation of epoxidized soybean oil into carbonated soybean oil under ambient pressure of CO2 gas, with tetrabutylammonium bromide/calcium chloride as catalyst/co‐catalyst couple. Ring‐opening reaction of the carbonated oil with ethanolamine led to the desired polyol. A one‐pack polyurethane system was prepared via combination of the polyol and a blocked polyisocyanate. The polyol and final polyurethanes were fully characterized, and their physical, mechanical, viscoelastic and electrical insulating properties were studied.CONCLUSION: The application of this newly developed soybean oil‐based polyol for preparation of electroinsulating casting polyurethanes was examined. The prepared soy‐based polyurethanes offered excellent thermal and electrical insulating properties. Also, tunable physical and chemical properties for the final polyurethanes were achieved by replacing part of the soybean oil‐based polyol with poly(propylene glycol) (Mn = 1000 g mol−1). Copyright © 2008 Society of Chemical Industry

CO Gas Sensing by Ultrathin Tin Oxide Films Grown by Atomic Layer Deposition Using Transmission FTIR Spectroscopy

Ultrathin tin oxide films were deposited on SiO2 nanoparticles using atomic layer deposition (ALD) techniques with SnCl4 and H2O2 as the reactants. These SnO(x) films were then exposed to O2 and CO gas pressure at 300 degrees C to measure and understand their ability to serve as CO gas sensors. In situ transmission Fourier transform infrared (FTIR) spectroscopy was used to monitor both the charge conduction in the SnO(x) films and the gas-phase species. The background infrared absorbance measured the electrical conductivity of the SnO(x) films based on Drude-Zener theory. O2 pressure was observed to decrease the SnO(x) film conductivity. Addition of CO pressure then increased the SnO(x) film conductivity. Static experiments also monitored the buildup of gas-phase CO2 reaction products as the CO reacted with oxygen species. These results were consistent with both ionosorption and oxygen-vacancy models for chemiresistant semiconductor gas sensors. Additional experiments demonstrated that O2 pressure was not necessary for the SnO(x) films to detect CO pressure. The background infrared absorbance increased with CO pressure in the absence of O2 pressure. These results indicate that CO can produce oxygen vacancies on the SnO(x) surface that ionize and release electrons that increase the SnO(x) film conductivity, as suggested by the oxygen-vacancy model. The time scale of the response of the SnO(x) films to O2 and CO pressure was also measured by using transient experiments. The ultrathin SnO(x) ALD films with a thickness of approximately 10 A were able to respond to O2 within approximately 100 s and to CO within approximately 10 s. These in situ transmission FTIR spectroscopy help confirm the mechanisms for chemiresistant semiconductor gas sensors.

Measurements of the17O Excess in Water with the Equilibration Method

The equilibration method is the present-day standard method for measuring delta18O in water samples. The mass-to-charge ratio of 45 is measured at the same time but generally not used for further analysis. We show that an improved equilibration method can be used for precise determination of delta17O in addition to that of delta18O, and therefore can estimate 17O excess values to a precision of better than 0.1 per thousand. To control the masking effect of the 14 times more abundant 13C on mass 45, we propose to use a chemical buffer in the water samples to keep the pH value and therefore the fractionation during the equilibration process of the 13C constant. With this improved method, the precision for the delta18O value could also be slightly improved from 0.05 to 0.03 per thousand. Furthermore, we discuss the influences of the amount of water, the temperature, the CO2 gas pressures, and changes in the pH during the measuring procedure on oxygen and carbon isotopes. We noticed that measured delta45 values are a good control for delta18O measurements. This study tries to fathom the possibilities and limitations of the equilibration method for measuring 17O excess values of water samples.

Época de aplicação e desempenho de fungicidas no controle da giberela em trigo

O controle químico da giberela pode ser influenciado pelo momento da aplicação e pelo fungicida. Na safra agrícola de 2004, os fungicidas foram aplicados em três estádios de crescimento da planta: início da floração, metade da floração completa e no início do desenvolvimento de grão leitoso. Em 2005, uma única aplicação foi feita no início da floração, testando-se maior número de fungicidas. As aplicações foram feitas com pulverizador manual, com pressão gerada por gás CO2, numa vazão de 200L ha-1. A intensidade da giberela foi quantificada pela incidência, severidade e índice de giberela. Também foram determinados o rendimento de grãos, o peso de mil grãos e a incidência de Fusarium graminearum nos grãos colhidos. O maior percentual de controle da giberela ocorreu com aplicação feita no início da floração. Os fungicidas metconazole (0,09L i.a. ha-1), tebuconazole (0,15), trifloxistrobina+tebuconazole (0,075+0,15), azoxistrobina+ciproconazole (0,060+0,024) e piraclostrobina+epoxiconazole (0,099+ 0,037) reduziram significativamente a intensidade da giberela, obtendo-se controle médio de 46% na incidência, 46,6% na severidade e 71,2% no índice de giberela. Esses fungicidas mostraram ganho médio no rendimento de grãos de 23,4%, porém apresentaram baixa eficácia no controle da infecção de F. graminearum nos grãos.

Carbonate binders by “cold sintering” of calcium carbonate

The solubility of calcium carbonate (limestone) particles depends on the amount of CO2 dissolved in the water, which is a function of temperature and the pressure of CO2 that is in equilibrium with water. At a constant temperature, increasing CO2 pressure increases the solubility of CaCO3, and decreasing CO2 pressure favours the crystallisation of CaCO3. This dissolution–crystallisation behaviour of CaCO3 can be used in the development of carbonate binders—a process called “cold sintering”—of limestone. This paper examines the effect of a range of parameters on the cold sintering process of limestone powder. The parameters studied are CO2 gas pressure (atmospheric, 10 atm and 35 atm), exposure time (0–90 min), post-compaction pressure (10 and 15 MPa) and compact pressing time (10–60 min). The water/limestone powder ratio was kept constant at 0.2 (by weight). The compressive strength of the limestone compacts was used as a measure of the efficiency of the carbonate binder formation process, and scanning electron microscopy was used to study the microstructural developments. The results show that carbonate binders can be produced by cold sintering of limestone powder. Exposure of limestone compacts to high CO2 pressure followed by post-compaction at high mechanical pressure, enhances the strength of the compact. From the microstructural data, it is evident that newly formed calcium carbonate crystal growths are responsible for the strength improvements observed. The amount of water that is used in the limestone powder mixture is one factor that controls the quantity of the cementing phase. Future work has to be focussed on the application of methods to further increase the solubility of calcium carbonate, as the amount of calcium carbonate available for recrystallisation is important in producing a strong binder.

Electrosorbed carbon monoxide monolayers on Pt(1 1 1)

We review structures of high-density CO monolayers on Pt(1 1 1) surfaces in CO-saturated electrolytes or in gaseous CO at near atmospheric pressure, using surface X-ray scattering (SXS) and scanning tunneling microscopy (STM). In electrolytes, we confirmed the well-known (2 × 2)-3CO and (√19 × √19)-13CO structures and were able to study the transition between them. For gas-phase studies, we were able to stabilize extremely well-ordered CO monolayers by emersion transfer from an electrochemical cell. We found that the hexagonal close-packed (2 × 2)-3CO structure is the equilibrium phase at room temperature in ∼1 atm CO gas pressure. This commensurate (C) phase transforms continuously to an incommensurate (IC) phase at elevated temperature (a second-order phase transition). We also confirm that the (√19 × √19)-13CO structure is stable at lower CO partial pressure. This C phase transforms discontinuously to an IC phase (a first-order phase transition). A tentative phase diagram and a brief review of structure details of the (2 × 2)-3CO and (√19 × √19)-13CO phases will be presented.

High-density electrosorbed carbon monoxide monolayers on Pt(111) under atmospheric pressure

We report structure studies of high-density CO monolayers on Pt(111) surfaces in equilibrium with gaseous CO near atmospheric pressure, using surface x-ray scattering (SXS) and scanning tunneling microscopy (STM). We were able to stabilize extremely well-ordered CO monolayers by emersion transfer from an electrochemical cell. We found the hexagonal close-packed $(2\ifmmode\times\else\texttimes\fi{}2)\text{\ensuremath{-}}3\mathrm{C}\mathrm{O}$ structure at room temperature in $\ensuremath{\sim}1\phantom{\rule{0.3em}{0ex}}\mathrm{atm}$ CO gas pressure. We also confirm the $(\sqrt{19}\ifmmode\times\else\texttimes\fi{}\sqrt{19})\text{\ensuremath{-}}13\mathrm{C}\mathrm{O}$ structure previously proposed in STM studies [Vestergaard et al., Phys. Rev. Lett. 88, 259601 (2002)]. Based on SXS and STM measurements, a tentative phase diagram is proposed. Detailed SXS structure studies of the $(2\ifmmode\times\else\texttimes\fi{}2)\text{\ensuremath{-}}3\mathrm{C}\mathrm{O}$ structure suggest a surface structure and substrate reconstruction less symmetric than previously studies suggested. We also find that $(\sqrt{19}\ifmmode\times\else\texttimes\fi{}\sqrt{19})\text{\ensuremath{-}}13\mathrm{C}\mathrm{O}$ structure induces substrate reconstructions including the dimerization of Pt bonded to bridging CO and the rotation of the Pt cluster with atop CO.

高気圧CO2、N2ガス中交流電圧印加時における 電極表面粗さ、絶縁コーティングの検討

高気圧CO2、N2ガス中交流電圧印加時における 電極表面粗さ、絶縁コーティングの検討

Absorption of Ammonia Gas from a Composting Plant using Carbonated Water

Odors from composting plants are a serious public nuisance. Ammonia gas (NH3) is the main molecule responsible for bad odors that arise from composting of organic wastes such as animal manure. Carbon dioxide (CO2) is known to increase the solubility of NH3 in water. Taking that effect of CO2 into account, numerical calculation of the absorption of NH3 into water was carried out under the assumption of quasiequilibrium conditions. Based on that theoretical consideration, the authors propose a new deodorizing process that consists of a carbonator and a reactor. The carbonated water produced by pressurized CO2 gas is transported to the reactor, where NH3 gas dissolves efficiently in the water. Carbonated water with NH3 is useful as a liquid fertilizer.It is expected that the consumption of water in the new process is significantly lessened compared to that consumed in traditional processing. According to theoretical considerations, 100ppm NH3 in 1m3 air can be reduced to 10ppm after deodorization using 0.1kg carbonated water at CO2 concentration of 2×10-3kg L-1.

Atomistic packing models for experimentally investigated swelling states induced by CO2 in glassy polysulfone and poly(ether sulfone)

AbstractAtomistic packing models have been created, which help to better understand the experimentally observed swelling behavior of glassy polysulfone and poly (ether sulfone), under CO2 gas pressures up to 50 bar at 308 K. The experimental characterization includes the measurement of the time‐dependent volume dilation of the polymer samples after a pressure step and the determination of the corresponding gas concentrations by gravimetric gas‐sorption measurements. The models obtained by force‐field‐based molecular mechanics and molecular dynamics methods allow a detailed atomistic analysis of representative swelling states of polymer/gas systems, with respect to the dilation of the matrix. Also, changes of free volume distribution and backbone mobility are accessible. The behavior of gas molecules in unswollen and swollen polymer matrices is characterized in terms of sorption, diffusion, and plasticization. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1874–1897, 2006

Critical review of carbon monoxide pressure measurements in the uranium–carbon–oxygen ternary system

For high temperature reactors (HTR), the high level of fuel operating temperature in normal and accidental conditions requires to predict the possible chemical interactions between the fuel components. Among the concerns of the TRISO fuel particle thermomechanical behavior, it is necessary to better understand the carbon monoxide formation due to chemical interactions at the UO2 kernel and graphite buffer’s interface. In a first step, the thermodynamic properties of the U–C–O system have to be assessed. The experimental data from literature on the equilibrium CO gas pressure measurements in the UO2–UC2–C ternary section of the U–C–O system are critically reviewed. Discrepancies between the different determinations can be explained – (i) by the different gaseous flow regimes in the experiments and – (ii) by the location of the measuring pressure gauge away from the reaction site. Experimental values are corrected – (i) from the gaseous flow type (molecular, transition or viscous) defined by the Knudsen number and – (ii) from the thermomolecular effect due to the temperature gradient inside the experimental vessels. Taking account of the selected and corrected values improves greatly the consistency of the original set of measurements.