Open-air System Research Articles

Factors influencing solar drying performance of the red algae Gracilaria chilensis

The aim of this study was to establish the optimal conditions of distinct factors affecting the performance of a closed solar dryer in drying Gracilaria chilensis, a commercially important red algae. The evaluated factors were algae arrangement (vertical versus horizontal), baffle existence (present versus absent), and air fan use (on versus off). Process productivity was maximized when the algae were arranged horizontally, a baffle was present, and the air fan was turned on. Of these, air fan use was the most important determinant of process performance. This optimized solar dryer system was then compared against the productivity of an open-air system. The solar dryer achieved a greater degree of moisture evaporation than open-air drying (86.1% versus 67.6%, respectively). This result is directly associated with the recorded peaks in air temperature (41.3 °C in the solar dryer versus 21.7 °C outside of the solar dryer). The specific energy consumption required for the optimized solar dryer process was 1.64 kWh/kg, as due to the energy requirements of the air fan and recirculation pump. Solar drying is very effective in drying G. chilensis when parameters are optimized.

Characteristic of the Nanoparticles Formed on the Carbon Steel Surface Contacting with 3d-Metal Water Salt Solutions in the Open-Air System.

The contact of a steel electrode with water dispersion medium in an open-air system leads to the development of various polymorphic iron oxides and oxyhydroxides on the steel surface. Whereas the usage of distilled water causes the obtaining of Fe(II)-Fe(III) layered double hydroxides (green rust) as a primary mineral phase, but in the presence of inorganic 3d-metal water salt solutions, mixed layered double hydroxides (LDHs) together with non-stoichiometric spinel ferrite nanoparticles are formed on the steel surface. Mixed LDHs keep stability against further oxidation and complicate the obtaining of spinel ferrite nanoparticles. Thermal treatment of mixed LDHs among other mineral phases formed via the rotation-corrosion dispergation process at certain temperatures permits to obtain homogenous nanoparticles of spinel ferrites as well as maghemite or hematite doped by 3d-metal cations.

Synthesis and Structural Characterization of Monocrystalline <i>α</i>-V<sub>2</sub>O<sub>5</sub> Nanowires

A stable one-dimensional system in an orthorhombic α-V2O5 nanowires monocrystalline structure was obtained by a solvothermal method from a polymorphic V2O5 structure. The starting material was firstly submitted to acid hydrolysis in H2O2 followed by a solvothermal treatment. The outcome of this procedure, a metastable phase of the one-dimensional system V10O24·12H2O/V3O7·H2O, was subsequently reoxidized by controlled heating in an open air system. The final product was an orange crystalline solid mainly formed by monocrystalline nanowires of α-V2O5 having lengths of tens of micrometers and widths of about 75 nm with a preferential [200] growth direction. It was found that the pH value of the initial solution plays an important role in the formation of the crystalline phase in the final products. Characterization was performed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). This study offers an alternate route for the synthesis of vanadium oxides and related compounds.

A Catalyst-Free Synthesis of Phosphinic Amides Using O-Benzoylhydroxylamines.

A practical approach for the synthesis of phosphinic amides via the coupling of secondary phosphine oxides (SPOs) with O-benzoylhydroxylamines has been reported. Simply heating the mixture of SPOs and O-benzoylhydroxylamines in the presence of K(2)CO(3) gave the phosphinic amides in moderate to excellent yields under an open air system. This method provides a practical and catalyst-free method for the synthesis of various synthetically valuable phosphinic amides.

ChemInform Abstract: Aerobic Oxidation of Alcohols by Using a Completely Metal‐Free Catalytic System.

A metal-free reaction system of air, NH4NO3(cat), 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)(cat), and H+(cat) is introduced as a simple, safe, inexpensive, efficient and chemoselective mediator for aerobic oxidation of various primary and secondary benzyl and alkyl alcohols, including those bearing oxidizable heteroatoms (N, S, O) to the corresponding aldehydes or ketones. Air oxygen under slight overpressure plays the role of the terminal oxidant, which is catalytically activated by redox cycles of nitrogen oxides released from a catalytic amount of NH4NO3 and cocatalyzed by TEMPO (nitroxyl radical compound), under acidic conditions, which are essential for an overall activation of the reaction system. The synthetic value of this reaction system and its green chemical profile was illustrated by a 10 g scale-up experiment, performed in an open-air system by using a renewable and reusable polymer-supported form of TEMPO (OXYNITROX®S100). The reaction solvent was recovered by distillation under atmospheric pressure, and the pure final product was isolated under reduced pressure; the acid activators (HCl or H2SO4) were recovered as ammonium salts.

Annual nitrous oxide emissions from open-air and greenhouse vegetable cropping systems in China

A field experiment was conducted to quantify annual nitrous oxide (N2O) fluxes from control and fertilized plots under open-air and greenhouse vegetable cropping systems in southeast China. We compiled the reported global field annual N2O flux measurements to estimate the emission factor of N fertilizer for N2O and its background emissions from vegetable fields. Fluxes of N2O were measured using static chamber-GC techniques over the 2010–2011 annual cycle with multiple cropping seasons. The mean annual N2O fluxes from the controls were 46.1 ± 2.3 μg N2O-N m−2 hr−1 and 68.3 ± 4.1 μg N2O-N m−2 hr−1 in the open-air and greenhouse vegetable systems, respectively. For the plots receiving 900 kg N ha−1, annual N2O emissions averaged 90.6 ± 8.9 μg N2O-N m−2 hr−1 and 106.4 ± 6.6 μg N2O-N m−2 hr−1 in the open-air and greenhouse vegetable systems, respectively. By pooling published field N2O flux measurements taken over or close to a full year, the N2O emission factor for N fertilizer averaged 0.63 ± 0.09 %, with a background emission of 2.67 ± 0.80 kg N2O-N ha−1 in Chinese vegetable fields. Annual N2O emissions from Chinese vegetable systems were estimated to be 84.7 Gg N2O-N yr−1, consisting of 72.5 Gg N2O-N yr−1 and 12.2 Gg N2O-N yr−1 in the open-air and greenhouse vegetable systems, respectively. While N2O emissions from the greenhouse vegetable cropping system tended to be slightly higher compared to the open-air system in our experiment, the synthesis of literature data suggests that N2O emissions would be greater at low N-rates but smaller at high N-rates in greenhouse systems than in open-air vegetable cropping systems. The estimates of this study suggest that vegetable cropping systems covering 11.4 % in national total cropping area, contributed 21–25 % to the total N2O emission from Chinese croplands.

1,4-Dioxane degradation by oxidation and sonication in the presence of different-sized ZVI in open-air system

We investigated the effect of particle size during oxidation and the sono-Fenton process in an open-air system (without air supply) containing microscale zero-valent iron (MZVI) and nanoscale zero-valent iron (nZVI) on the degradation of 1,4-dioxane (1,4-D) at neutral pH. Time-dependent concentrations of 1,4-D, H2O2, and ionic Fe were measured as a function of MZVI and nZVI loading during oxidation and sono-Fenton (without addition of H2O2). The optimal loading of MZVI and nZVI for 1,4-D degradation were determined to be 0.5 g/L during both oxidation and sono-Fenton, and 0.2 and 0.1 g/L during both oxidation and sono-Fenton, respectively. Overall, the optimal loading of MZVI in both the oxidation and sono-Fenton system showed better 1,4-D degradation efficiency compared with the optimal loading of nZVI for 6 h: approximately 60.00 and 76.65% removal efficiencies for MZVI oxidation and sono-Fenton, respectively, while approximately 47.13 and 60.98% removal efficiencies for nZVI oxidation and sono-Fenton, respectively. Consequently, the smaller size of ZVI did not enhance 1,4-D degradation efficiency during the oxidation and sono-Fenton at neutral pH.

Studies on the effect of different solar dryers on the vitamin content of tomato (Solanum lycopersicon)

Samples of tomato fruit were dried under four different conditions: open-air sun drying method and by using three different models of integral passive solar dryers which include green house solar dryer, sun-tracking solar dryer, and latitudinal box solar dryer. The fresh tomato samples and the dried samples were analysed for vitamins A, C, and E. The results showed a significant difference in the concentrations of vitamins A, C, and E between the fresh samples and the dried samples for all drying systems. While vitamin C is reduced in concentration for all dried samples, vitamins A and E are increased significantly with open-air system having the highest value in vitamin C concentration while latitudinal box dryer gives the best result in terms of vitamins A and E retention. All year round, availability of tomato could be enhanced by chipping and drying. Packaging and marketing of dried chips in small quantities could be a lucrative entrepreneurial endeavour for the business minded.

Three-mode pneumatic management of marine U-tank systems

This paper deals with a new pneumatic control strategy for the roll damping enhancement of marine U-tank stabilizers. The proposed technique consists in a three-mode operation, where the control is active only within a limited resonant range around the ship natural frequency, whereas the control valves are kept closed in the remaining frequency range. Moreover the connection valve between the two air chambers is either closed or partially opened for the low or high frequencies, respectively. The pressurized air for the active control is fed by a turbo-blower set aboard and operates accelerating the motion of the water mass in the U-duct. The theoretical analysis is conducted in the hypothesis of harmonic excitation and includes an equivalent linearization procedure for the turbulent air flow through the upper valve regulating the efflux from the one to the other tank. The application of the laws of thermodynamics to the open air system overhanging the water in each tank chamber reveals the negligibility of the heat transfer through the tank wall in comparison with the mass transfer effects. As a practical result, the mathematical model permits developing a suitable optimization process with the aim at the best damping operation, which however must be subjected to two fundamental constraints: the system stability and the pre-imposed limit power absorbable from the control equipment. Comparing with natural damped passive systems, a reduction of the order of 20–40% can be roughly attained for the resonant roll amplitude, depending on the supplied control power.

Maximising the energy output of a PVT air system

Simultaneously generating both electricity and low grade heat, photovoltaic thermal (PVT) systems maximise the solar energy extracted per unit of collector area and have the added benefit of increasing the photovoltaic (PV) electrical output by reducing the PV operating temperature. A graphical representation of the temperature rise and rate of heat output as a function of the number of transfer units NTUs illustrates the influence of fundamental parameter values on the thermal performance of the PVT collector. With the aim of maximising the electrical and thermal energy outputs, a whole of system approach was used to design an experimental, unglazed, single pass, open loop PVT air system in Sydney. The PVT collector is oriented towards the north with a tilt angle of 34°, and used six 110Wp frameless PV modules. A unique result was achieved whereby the additional electrical PV output was in excess of the fan energy requirement for air mass flow rates in the range of 0.03–0.05kg/sm2. This was made possible through energy efficient hydraulic design using large ducts to minimise the pressure loss and selection of a fan that produces high air mass flow rates (0.02–0.1kg/sm2) at a low input power (4–85W). The experimental PVT air system demonstrated increasing thermal and electrical PV efficiencies with increasing air mass flow rate, with thermal efficiencies in the range of 28–55% and electrical PV efficiencies between 10.6% and 12.2% at midday.

Conversion of Low Density Polyethylene (LDPE) and Polypropylene (PP) Waste Plastics into Liquid Fuel Using Thermal Cracking Process

In every sector of the world today energy is essential. Energy has many forms such as electricity, transportation fuel and so on. A large amount of energy is produced from crude oil, which is used to produce petroleum and petroleum to produce daily usable plastics. The solution to the above mentioned problems can be solved through the utilization of the new develop technology. This new developed technology will remove these hazardous waste plastics from the environment and convert them into eco friendly liquid fuel. The process is used to convert these waste plastics into liquid fuel creates no harmful emissions and can be produced at a very little overall cost. The thermal process utilized to break down the hydrocarbon chains of the polymers and convert them into liquid fuel. A Steel reactor with temperature range from 100 oC to 400 oC is utilized for the plastic thermal degradation process. The process yield about 80-90% liquid product. The experiment is conducted under a fume hood and open air system, no vacuum process is applied in this particular thermal cracking process.

Studies on the Effect of Different Solar Dryers on the Vitamin Content of Tomato (Solanum lycopersicon)

Samples of tomato fruits were dried under four different conditions: open-air sun drying method and by using three different models of integral passive solar dryers which include Green house solar dryer, Sun-tracking solar dryer and Latitudinal box solar dryer. The fresh tomato samples and the dried samples were analysed for vitamins A, C and E. The results showed a significant difference in the concentrations of Vitamins A, C and E between the fresh and the dried samples for all drying systems. While Vitamins C reduced in concentration for all dried samples, Vitamins A and E increased significantly with open-air system having the highest value in vitamin C concentration while latitudinal box dryer gave the best result in terms of vitamins A and E retention. All year round availability of tomato could be enhanced by chipping and drying. Packaging and marketing of dried chips in small quantities could be a lucrative entrepreneurial endeavour for the business minded.

Influence of dc Pulsed Atmospheric Pressure Plasma Jet Processing Conditions on Polymer Activation

AbstractPlasma treatments are widely used to activate polymer surfaces prior to adhesive bonding. This study investigates the influence of plasma treatment conditions on the surface activation of a range of polymers using the PlasmaTreat (Open Air) system. In this study the effect of dc pulse plasma cycle time, compressed air flow rate and the plasma jet nozzle to substrate distance on the plasma discharge was examined. The influence that the dc pulse plasma cycle time parameter has on the activation of polypropylene, polystyrene and polycarbonate was also investigated. The level of polymer surface activation was evaluated based on the change in water contact angle after plasma treatment. The polymer surface properties were also monitored using AFM and XPS measurements. The heating effect of the plasma was monitored using both infrared thermographic camera and thermocouple measurements. Plasma diagnostics measurements were obtained using the photo‐diode and optical emission spectroscopy techniques. From this study it was concluded that for the PlasmaTreat system the level of plasma activation was closely correlated with the dc pulsed plasma cycle time, which is a measure of the plasma intensity. For example, the more intense plasma obtained with shorter cycle times gave higher levels of polymer activation. The optimized pulsed plasma cycle times were found to be specific for a given polymer type and related to their thermal properties. The pulsed cycle times were also found to correlate with both the substrate and plasma gas temperatures. magnified image

Reinforcement Technology of Space Grid Structure for Reconstruction of Shandong Qufu Xingtan Theater

Shandong Qufu Xingtan Theater, originally built for an open-air theater, was designed as a one-time temporary structure with bolt ball junction double-layer regular pyramids grid structure roofing system. Because of the transformation of open-air structure system to an enclosed construction, some members of the space grid structure can not meet the required bearing capacity. According to the mechanical performance of space grid structures, the reinforcement methods of “circular steel jacketing” and “lateral support” are conducted, which are based on the analysis of the stress and stability characteristics of different grid members. By using the methods given above, the stress and slenderness ratio is decreased. The results indicate that the two reinforcement methods can reduce the difficulty in construction, shorten the construction period, and gain good economic and social benefit.

Condensation-assisted assembly of large 2D colloidal crystals

We examined the reorganization of polystyrene microparticles randomly deposited on a substrate into a large bi-dimensional colloidal crystal. The condensation–evaporation process used for this purpose is based on an open-air system. This configuration ensures on one hand the controlled formation of a continuous water film and on the other hand evaporation gradients at the origin of the fluid flows packing the microparticles into a compact assembly (colloidal crystal). The growth of the crystal is discussed on the basis of the microparticle–substrate interactions and the thickness of the condensed water film.

13C labeling of plant assimilates using a simple canopy-scale open air system

A simple system based on web-FACE technology was designed and implemented as an approach to label plant-assimilated carbon (C) with 13C. The labeling system avoids the use of a chamber or other enclosure, instead distributing CO2 heavily enriched in 13C at near atmospheric concentrations to the tree foliage through the use of porous tubing. The system was applied to three plantation grown juvenile larch (Larix spp.) trees during the daylight hours over the course of five days in the middle of the growing season. Relative to control trees, fumigation with enriched CO2 resulted in significantly 13C-enriched foliar respiration and nighttime soil respiration. Enrichment was also created in the foliar tissue, but differences between labeled and control trees were not statistically significant. Temporal and spatial variation in the strength of the isotopic label did occur, and modifications to the system are suggested to limit the variation. The approach should enable the implementation of pulse-chase experiments designed to understand plant source-sink relationships or experiments designed to understand the flux of C from plant roots into the soil food web.

Open Air Deposition of SiO2 Films by an Atmospheric Pressure Line‐Shaped Plasma

AbstractSummary: A line‐shaped atmospheric pressure filamentary plasma is developed to carry out the open air deposition of silicon oxide films from N2/hexamethyldisoxane (HMDSO) mixtures with/without adding oxygen. FT‐IR, XPS, SEM, and ellipsometry were used to analyse the samples. It is found that the deposited films present mainly inorganic characteristics even without an oxygen admixture in the open air system. Smooth, continuous, and uniform films can be formed at relatively low monomer content. By increasing the monomer content for a fixed power density or oxygen in the input gases, the deposition rates increase and then show a plateau, suggesting that there exists saturation values for the deposition rates corresponding to the monomer and oxygen content. By the comparison of films deposited in the open air device and in a controlled nitrogen atmosphere in the same device, the important role of the oxygen in the open air reactor has been shown. This study exhibits a potential of open air deposition at atmospheric pressure to form SiO2 films for large‐scale deposition.An FT‐IR spectrum of an SiOx film deposited in open air without adding any oxygen to the discharge.magnified imageAn FT‐IR spectrum of an SiOx film deposited in open air without adding any oxygen to the discharge.

Effect of Temperature and Humidity on Sperm Morphology in Duroc Boars Under Different Housing Systems in Thailand

The aim of this study was to investigate the effect of season, temperature, humidity, age of the boar, and semen collection interval on sperm morphology in Duroc boars in Thailand, kept either in a conventional open air system (CONV) or in an evaporative cooling system (EVAP). In total, 1176 ejaculates from 110 sexually mature boars in six CONV herds and five EVAP herds were morphologically examined during a one-year period. Analysis of variance was applied to the data. Minor differences in the sperm morphology traits analyzed were found between the housing systems. There was a significant seasonal effect (two-month periods) on the percentage of morphologically normal spermatozoa (normal1), morphologically normal spermatozoa including spermatozoa with distal cytoplasmic droplets (normal2), proximal cytoplasmic droplets (prox), and sperm head abnormalities (P<or=0.001). Temperature had a significant effect on normal1 in the CONV system (P<or=0.01) and in the EVAP system (P<or=0.05), and on normal2 (P<or=0.05) and prox (P<or=0.001) in both systems. Humidity had a significant effect on prox (P<or=0.05) in the EVAP system. The results also indicate that the sperm morphology traits were mildly affected by the housing systems investigated. A seasonal variation in sperm morphology was found, and high temperatures and high humidity had negative effects on sperm morphology.

Effect of temperature and humidity on sperm production in Duroc boars under different housing systems in Thailand

The aim of this study was to investigate the variation in temperature and humidity during a 12-month period in boar stables in Thailand with either conventional open air system (CONV) or evaporative cooling system (EVAP), as well as the effect of season, temperature, humidity, age of the boar, and semen collection interval on sperm production in Duroc boars kept in these stables. Ejaculates were collected from sexually mature Duroc boars in six CONV herds and five EVAP herds during a 1-year period. A total of 15,630 semen records were included in the statistical analyses. Temperature was higher and humidity was lower in the CONV system compared to the EVAP system. Twenty-one days moving-average of daily maximum temperature and minimum humidity with 7 and 14 days lag time was calculated and merged with each semen record. Besides the fixed effects included in the statistical models, the random effects of herd and boar within herd were included. No significant effect of system on volume of the ejaculate and total sperm production (TSP) was found, but there was a significant effect of month, age of the boar and collection interval on both volume and TSP ( P<0.001). The interaction between system and month was significant ( P<0.001). Temperature had a significant effect on volume in both systems ( P<0.01), and on TSP in the CONV system ( P<0.001) and in the EVAP system ( P<0.05). Humidity had a significant effect on both volume and TSP ( P<0.001) in the EVAP system. Volume and TSP decreased when temperature and humidity exceeded 30 °C and 40%, respectively, in the CONV system ( P<0.05), and 27 °C and 70%, respectively, in the EVAP system ( P<0.01). In conclusion, this study showed a seasonal variation in sperm production, and minor differences in the seasonal pattern were found between the two housing systems. High temperature and high humidity had negative effects on sperm production. The EVAP system might be one alternative way to reduce the seasonal variation in sperm production.

Test method for evaluation of anti-scale devices for cooling condensers

Can new types of anti-scaling devices prevent scaling on condensing pipes in industrial cooling condensers and supersede conventional water treatment? To examine this question a test method has been developed, test rigs have been built and different kinds of anti-scale devices have been tested. As cooling towers are based on an open-air system with evaporation of water they will have higher demands on the effectiveness of the anti-scale devices compared to the closed systems which are typical drinking water systems in buildings. The test method is based on an open-air system. The rigs are mobile and can be used to give an indication of whether it is possible to treat the local water with an anti-scale device. The result of the test is a scaling rate and a germination time. In addition to these tests the anti-scale devices have been tested in the field at cooling condensers.