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This study proposes a new method using the combination of flocculation and prefabricated horizontal drain (PHD) assisted with vacuum pressure for rapid dewatering of high-water-content dredged slurry. First, to demonstrate the superiority of using PHD over the more commonly used prefabricated vertical drain (PVD), experiments were conducted to compare the dewatering performance between the PHD and the PVD. Then six model tests with the proposed dewatering method were performed with various contents of flocculant (anionic polyacrylamide (APAM)) to investigate the effect of APAM content on the dewatering process and soil properties (i.e. undrained shear strength, permeability and compressibility). Furthermore, particle size distributions of the slurry before and after model tests were measured to analyze the dewatering behavior and changes in material properties. Finally, particle loss during vacuum consolidation for various APAM contents were compared to study the flocculation effect on clogging problem. Results indicate that the proposed method can prevent significant bending deformation of the drain board and mitigate clogging of the drain filter and, thus, can significantly accelerate the dewatering process of high-water-content dredged slurry.

In this study, the simultaneous effect of fluid pressure, vacuum pressure, and fluid temperature in the microfiltration process of tomato juice was investigated. For this purpose, a microfiltration device with a ceramic filter under pressure-vacuum combination was developed. Next, the effects of the device variables were investigated and optimised in the tomato juice microfiltration process. The results showed the statistically significant effects of fluid pressure, vacuum pressure, and fluid temperature on permeate flux response and total energy consumption. Also, they showed the effects of fluid pressure and fluid temperature on the response variables of lycopene and vitamin C content of tomato juice microfiltration. The optimal conditions of the microfiltration process of tomato juice were achieved at a fluid pressure of 200 kPa, the vacuum pressure of 5 kPa, and fluid temperature of 26 °C with a desirability index of 0.967. Under the optimal conditions, values of response variables including permeate flux, total energy consumption, lycopene, and vitamin C content of tomato juice filter were 215.09 × 10−6m3m−2s−1, 0.044 kWh, 2.42 mg100 g−1, and 13.21 mg 100 g−1, respectively. Overall, this type of tomato juice microfiltration, in addition to preserving the valuable nutrients of tomato juice, can cause high permeate flux and low process energy consumption.

Thermodynamic and experimental studies was carried out on the process of Thanhhoa dolomite reduction to produce magnesium. Thermodynamically studied on the effect of pressure and temperature on reduction was carried out together with verification experiment. Results show that at appropriate temperature and vacuum pressure, Thanhhoa dolomite can be reduced using ferrosilicon as the reductant. The higher level of vacuum, the lower temperature required for reduction. Thermodynamic calculation pointed out that at a vacuum pressure of 600 Pa, the reduction temperature could be as low as 1140 °C. Experiment results indicated that at although reduction could be done at 1150 °C, the process efficiency was low, generally below 20%. Process efficiency enhanced as temperature increase and reaches the highest value of 85,8% at 1250 °C (25 wt.% ferrosilicon). The amount of ferrosilicon used also has influenced the process efficiency. After three hours of reduction, the obtained magnesium was very high in purity, 99.3%.

The effects of pressure (21.3, 41.3, 61.3, 81.3, and 101.3 kPa) and temperature (174–184 °C) applied during the post-frying centrifuge stage on the physico-chemical characteristics of atmospheric fried plantain chips were studied. Results showed that the surface temperature dropped very fast during the cooling process while the total oil content gradually increased. The oil uptake in the plantain chips increased by 7.7% after 9 min of post-frying cooling. Though an alteration in moisture and oil content was significantly affected (p 0.05) was observed among the samples centrifuged at different pressures. The application of vacuum pressure at 21.3 kPa together with temperature control for 5 min during the post-frying centrifuge stage was significantly effective (p

The vacuum drying (VD) process of virgin brown sugar powder (VBSP) was optimized by response surface methodology. The influences of drying temperature (75–85 °C), vacuum pressure (30–50 kPa) and material thickness (0.7–1.3 cm) on the response values of drying rate and total phenolic content (TPC) were investigated. The optimal conditions of 85 °C, 46 kPa and 1.01 cm were obtained. The sensory, physical and chemical properties of VBSP under optimal conditions showed that significant changes in colour, aw and moisture state, but not in sugar composition, were found. The TPC, protein content and free amino acid content were slightly reduced, while certain increases in the DPPH radical scavenging activity, N-nitro clearance and reducing power were observed. The results indicated that VD could provide good sensory and physicochemical properties to VBSP, in addition to cost and efficiency advantages.

Vacuum preloading is one of the popular methods improving the engineering properties of slurry ground with high water content. Commonly, the efficiency of vacuum preloading gradually decreased due to the clogging of prefabricated vertical drains (PVDs) and the low-vacuum transmission rate inside slurry. Thus, the calcium-based flocculants were used to accelerate the dewater capacity and enhance the soil strength during vacuum preloading. This paper performed a series of model tests to investigate the effect of calcium-based flocculants on the efficiency of vacuum preloading. It is found that the vacuum transmission rate was significantly improved by flocculants in comparison with raw slurry. Accordingly, the after-treatment undrained shear strength increased with the vacuum pressure, while the after-treatment water showed a decrease trend. This suggests that the increase of vacuum transmission rate inside the slurry due to the calcium-based flocculants was the main reason for the improvement of efficiency of vacuum preloading. In addition, there existed an optimal flocculants amount, where the vacuum pressure increased with flocculants’ amount up to this threshold value, followed by a decrease in vacuum pressure. This means that, at lower flocculants amount, the increase in soil flocs due to flocculation effect tended to refine the net-frame structure and water flow path, leading to an increase in the efficiency of vacuum preloading. When exceeding the optimal amount, overdosage of flocculants resulted in the clogging of PVDs due to large cemented soil particles, reducing the vacuum transmission rate inside the slurry. Hence, the after-treatment soil strength decreased with flocculants’ amount when it is higher than the optimal value.

Hydrogen-peroxide-based low-temperature sterilization is a new sterilization technology for temperature-dependent medical devices. The effect of the process parameters of hydrogen-peroxide-based sterilizer on the sterilization performance of process challenge devices (PCDs) needs to be investigated. Sterilant amount, operating temperature, vacuum pressure, diffusion time, and chamber loading of the sterilizer on the sterilization performance of PCDs were adjusted. Seven PCDs with various morphologies and material containing biological indicators (BI) (EZTest, Geobacillus stearothermophilus) were used to evaluate the sterilization performance. The sterilization success rates of PCDs were 86, 71, and 57% with controlled temperature and pressure, diffusion time, and sterilant volume injection, respectively. The PCD material and structure also obviously affected sterilization performance. The sterilization of PCD A is the least successful for all parameters. Meanwhile, the sterilization of PCD B was influenced by the diffusion time and the sterilant injection volume. PCD B and PCD C were successfully sterilized by controlling the temperature and pressure. The weights and volume of the sterilization loading chamber resulted in a different sterilization performance. Sterilization performances of PCD 1, PCD 2, and PCD 3 were

International audience; Gas separation by adsorption processes such as pressure swing adsorption (PSA) presents an attractive alternative for upgrading biogas to biomethane. A new vacuum pressure swing adsorption (VPSA) cycle is proposed for a unit designed to purify pre-cleaned biogas (40% CO 2 and 60% CH 4) in industrial conditions (feed flow rate more than 500Nm 3 /h and large-volume equipment). The process simulations performed to optimize the VPSA unit consider the kinetic separation of the feed components by using an appropriate carbon molecular sieve (CMS) adsorbent having a high kinetic separation selectivity for CO 2 with respect to CH 4. The designed VPSA unit is composed of five columns that perform three equalization steps. Minimizing methane losses during the regeneration steps necessitates injecting part of the off-gas rich in CO 2 at the bottom of the column during the production step to push the CH 4 forward. The produced biomethane meets the specification (97% CH 4) of grid injection purity. The developed cycle allows a CH 4 recovery of 92% to be obtained with a specific energy consumption of 0.35kWh/Nm 3 , thus meeting the initial requirements for industrial exploitation of VPSA technology for biomethane purification from biogas sources.

Palladium (Pd) membranes for industrial applications have gained much interest as of late. The purification of hydrogen through Pd membranes has therefore been proposed as a viable solution to traditional separation methods. Hydrogen permeation can be enhanced when coupled with a vacuum at the permeate side. In this study, the effect of different degrees of vacuum pressures on H2 permeation through a high-permselectivity Pd membrane in different binary gas mixtures was investigated and compared to those without vacuum. Three feed gases containing H2 concentrations of 90, 70, and 50 vol% were used. Hydrogen permeation rates were studied at 320, 350, and 380 °C under vacuum pressures ranging between 0 and −60 kPa. An increase in vacuum degree intensified H2 permeation. However, best performance improvements were observed at lower H2 concentrations, lower temperatures, and also at lower vacuum pressures for all gas mixtures. The highest performance improvement of 88.83% was with the gas mixture containing 50% H2 at 320 °C with a −15 kPa vacuum pressure. Hence, from an efficiency point of view, lower temperatures and vacuum pressures were preferred for all the gas mixtures. Activation Energies were also relatively lower for conditions with a vacuum for all gas mixtures.

Thermal management of Al composites is a crucial issue to keep the promising performance and excellent reliability of the devices. We revealed a novel method to enhance the surface property of graphite flakes (GF) with Cu and Ni coatings by chemical plating way. Taking advantage of Cu and Ni co-doped GF and silicon powders, the GF@Cu@Ni/Si/Al composites were fabricated by vacuum pressure infiltration method. The GF@Cu-30@Ni-10 composites revealed about 2 times larger TC (474.4 W/m·K) and lower CTE 6.22 ppm/K than neat Al. Our strategy for highly TC offers not only the advanced process for dispersing reinforcements but also an extremely simple way for the anisotropic composites with high TC and low CTE.

This paper demonstrates the application of a graphene–ferric oxide (hollow mesoporous α-Fe2O3 microspheres) nanocomposite for the measurement of vacuum pressure. Numerous research and industrial sy...

This study was conducted to enhance the physical, mechanical and thermal properties of the short cycle coconut wood (SC-CTL) by impregnating with the kraft black liquor (BL) and black liquor/phenol formaldehyde (BL/PF) resin. The SC-CTL was impregnated with different kraft BL and BL/PF resin concentrations (i.e., 10, 15, 20 and 25% w/w) using the vacuum pressure method. Dimensional stability, mechanical and thermal properties of the impregnated SC-CTL were analyzed according to the standards. The results showed that the impregnation of BL/PF resin into SC-CTL have improved the coconut wood’s dimensional stability, mechanical and thermal properties. The morphology of coconut wood’s cells loaded with BL/PF resin clearly showed a full penetration. The results also suggested that the addition of 20% BL/PF resin was sufficient to enhance the dimensional stability, mechanical and thermal properties of SC-CTL. Thus, it is evident that the BL has the potentiality to be used as impregnant in SC-CTL through impregnation with vacuum-pressure method.

In this paper, we assess the performance of vacuum pressure swing adsorption (VPSA) for co-purification of H2 and CO2 through modelling and process optimization. VPSA allows for the integration of ...

In this study, a novel osmotic membrane was developed by polyamide (PA) coating on the tubular electrospun nanofiber (TuEN) support membrane. Water and reverse salt flux properties of the obtained membrane were investigated by applying pressure in addition to the osmotic forces. Surface characterization of the membrane was carried out by Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) analyses and flux performance tests were performed in both cross flow and submerged membrane setups. Applying pressure from the feed to the concentrate side had significant effects on the water and salt fluxes. Higher pressure differences between the feed and concentrate sides resulted in unexpected high water fluxes up to 500 Lm(-2)h(-1) (LMH). Besides, the pressure helps to transfer the salt content of feed water into the concentrate side, differently from the osmotic process preventing the salinity build-up at the feed side. PA coated TuEN membrane operated under pressure will exhibit a favorable solution in water/wastewater treatment applications, especially for membrane bioreactors (MBR) in terms of preventing salt accumulation in the bioreactor, decreasing the membrane fouling, increasing the volume of product water, and enabling the concentrate management.

Changes to industrial fermentation processes are rare, largely due to the impact on viability for Saccharomyces spp., related to environmental stresses during the process such as: osmotic pressure,...

In this paper, a feasibility study was carried out to evaluate cyclic adsorption processes for capturing CO2 from either shifted synthesis gas or H2 PSA tail gas of an industrial-scale SMR-based hydrogen plant. It is expected that hydrogen is to be widely used in place of natural gas in various industrial sectors where electrification would be rather challenging. A SMR-based hydrogen plant is currently dominant in the market, as it can produce hydrogen at scale in the most economical way. Its CO2 emission must be curtailed significantly by its integration with CCUS. Two Vacuum Pressure Swing Adsorption (VPSA) systems including a rinse step were designed to capture CO2 from an industrial-scale SMR-based hydrogen plant: one for the shifted synthesis gas and the other for the H2 PSA tail gas. Given the shapes of adsorption isotherms, zeolite 13X and activated carbon were selected for tail gas and syngas capture options, respectively. A simple Equilibrium Theory model developed for the limiting case of complete regeneration was taken to analyse the VPSA systems in this feasibility study. The process performances were compared to each other with respect to product recovery, bed productivity and power consumption. It was found that CO2 could be captured more cost-effectively from the syngas than the tail gas, unless the desorption pressure was too low. The energy consumption of the VPSA was comparable to those of the conventional MDEA processes.

Operative delivery requires the use of a vacuum extractor, obstetricians can choose the appropriate vacuum extractor to make the delivery process smoother and safer. However, there is no biomechanical literature focused on the imposed effects of a vacuum extractor prepared with different materials and vacuum pressure on the fetal head during the process of delivery. Therefore, we first established and performed the finite element analytical model to explore the influences of vacuum extractors manufactured from different materials on the fetal head under various extractive pressures. The model of the vacuum extractor was designed as a hemispherical shape, and the material of the vacuum extractor was composed of silicone rubber and stainless steel for comparison. Four different vacuum pressures (500 cm H2O, 600 cm H2O, 700 cm H2O, and 800 cm H2O) were applied as the factors for investigation. The reaction force on the fetal head, von Mises stress of vacuum extractor, and von Mises stress on the skull of fetal head were measured and analyzed to evaluate the effects. The results revealed that subtle divergent influences of different vacuum pressures were observed, and the stainless-steel vacuum extractor induced a larger reaction force (358.04–361.37 N), accompanied with stress (13.547–13.675 MPa), on the fetal head than non-metallic or relatively softer materials. The results provide a reliable basis for selecting proper vacuum extractor during operative delivery to avoid obstetrical complications, such as scalp scratch, cephalohematoma and even intracerebral hemorrhage.

Phalaenopsis bellina is an important indigenous orchid with high commercial value. In this study, we established an efficient particle bombardment transformation system for P. bellina using the protocorm-like-bodies (PLBs) as target tissues. Leaf derived PLBs were proliferated on ½ strength Murashige and Skoog (MS) medium supplemented with 0.8 μM 2,4 dichlorophenoxyacetic acid (2, 4-D). Both physical and biological parameters affecting the transformation system were optimised using the green-fluorescent protein (GFP) and β-glucuronidase (GUS) as reporter systems. Optimal bombardment conditions with 6 cm target tissues distance, 1100 psi acceleration pressure, 1.0 μm gold particle size, 27 mmHg chamber vacuum pressure, single bombardment time, spermidine as DNA precipitation agent, 72 h post bombardment incubation time, 2 μg plasmid DNA in 0.15:0.12 pmol ratio (pSMCHS:p35SGFP) were successfully determined. Surviving PLBs transformants were successfully recovered from the hygromycin selection medium and verified using genomic PCR analysis. The established system is not only useful for a simple and reliable transient gene analysis but as well as generating stable transformants for selective traits improvement in orchids.

Porous aluminum is a new kind of functional material that is composed of a metal matrix and air holes. Under a negative vacuum pressure, trinitrotoluene (TNT) was filled into the pores and then con...

Jabon (Anthocephalus cadamba Miq.) is a fast-growing species that exhibits a lower natural resistance than that exhibited by the timber sourced from natural forests. Jabon’s resistance to termite attack can be improved by impregnating its wood structure with poisonous organic materials. This study examined jabon’s resistance to termite attack when impregnated with wood vinegar and an animal adhesive. The wood specimens were impregnated using sengon wood vinegar and an animal adhesive (8% and 10%, respectively) using a vacuum pressure machine. The specimens were tested for their resistance to subterranean and dry-wood termites according to Indonesian National Standard (SNI 7207-2014). The results denoted that jabon impregnated with wood vinegar and an animal adhesive concentration of at least 8% with the addition of 4% borate was effective to resist termite attacks. The impregnated jabon exhibited a lower weight loss and higher termite mortality when compared with those exhibited by the control specimens. Thus, the resistance class improved from class IV to class I.

Quinolone 006 is under development as an anti-methicillin-resistant Staphylococcus aureus quinolone antibiotic. A linear synthetic route was utilized to prepare the compound on a multi-kilogram scale with an overall yield of 71%. The process was optimized by controlling the temperature and the vacuum pressure. Examples of parameters examined in an effort to control the polymorphism of the 006 active pharmaceutical ingredient are described.

A study was performed for hydrogen purification of multicomponent mixture (N2/CO/CO2/CH4/H2=0.007/0.012/0.17/ 0.021/0.79) by one-column VPSA with AC5-KS. The performance of the one-column VPSA process can be predicted by a heat and mass transfer model with porous media adsorption. The simulation results agreed well with experimental data. The model was employed to assess the effects of P/F ratio and adsorption time in VPSA unit. The result showed, an increase in P/F ratio and a decrease in feeding time led to an increase in purity of hydrogen and a decrease in recovery. The Sequential Quadratic Programming method was applied to optimize the cycle. The result showed when pressure was set at 5 bar, feed rate was set at 5×10-5 m3/s and P/F ratio was set at 0.3, hydrogen was obtained with a purity of 99.17% and recovery of 58.94% after purification in N2/CO/CO2/CH4/H2 mixture.

Lemongrass essential oil has many compounds appropriate for application in foods, cosmetics, and pharmaceutical products. Of these, citral is a high-value compound of interest to industry. This work aims to evaluate the use of vacuum fractional distillation to separate lemongrass essential oil compounds, producing essential oil fractions containing high citral content. The effect of process parameters, namely vacuum pressure, type column, and energy input, on the fractionation time, content, and recovery of citral in the fractions, was investigated. The fractionation of lemongrass oils successfully provided five fractions, i.e., fraction 1 (F1), fraction 2 (F2), fraction 3 (F3), fraction 4 (F4), and fraction 5 (F5). GC-MS (Gas Chromatography-Mass Spectrometry) spectra showed that the main compound contained in F1 and F2 fractions was β-myrcene (&gt, 70%). Meanwhile, F4 and F5 were the two main fractions for citral recovery. The optimal conditions of the fractional distillation system included a column height of 400 mm, power input of 165 W, and pressure of 15 mmHg. These conditions correspond to the highest total citral content of 95%, with a recovery of 80% at the F4 and F5 fractions. Therefore, fractional vacuum distillation may be an effective method to upgrade lemongrass essential oil.

Microwave-assisted synthesis is known to accelerate the transesterification process and address the issues associated with the conventional thermal process, such as the processing time and the energy input requirement. Herein, the effect of microwave irradiation on the transesterification of palm oil methyl ester (PME) with trimethylolpropane (TMP) was evaluated. The reaction system was investigated through five process parameters, which were reaction temperature, catalyst, time, molar ratio of TMP to PME and vacuum pressure. The yield of TMP triester at 66.9 wt.% and undesirable fatty soap at 17.4% were obtained at 130 °C, 10 mbar, sodium methoxide solution at 0.6 wt.%, 10 min reaction time and molar ratio of TMP to PME at 1:4. The transesterification of palm oil-based methyl ester to trimethylolpropane ester was 3.1 folds faster in the presence of microwave irradiation. The total energy requirement was markedly reduced as compared to the conventional heating method. The findings indicate that microwave-assisted transesterification could probably be an answer to the quest for a cheaper biodegradable biolubricant.

There is an increasing interest in applying environmentally-friendly materials in wood protection technology. This include the use of less toxic active ingredients, as well as better fixation. This study investigates the formulation based on the combination of copper and Saqez resin on the physical and biological resistance properties of poplar wood. Samples were treated by either copper-ethanolamine (Cu/MEA) and/or Saqez resin at various treatment levels. A vacuum pressure procedure was applied. The retention, weight percent gain, water absorption, volumetric swelling, and decay resistance of the samples were then determined. The highest retention and weight percent gain were obtained at the samples treated with the combination of copper-based system and Saqez resin. Additionally, the combination of the copper and Saqez improved the physical properties and decay-resistance against white-rot fungus Trametes versicolor.

The scope of the present work was to study the effects of heat treatment (at different mild temperatures) on the physicomechanical properties of pine wood, and to find out if impregnation with nanosilver may have any potential influence on the impact of heat treatment. Impregnation of wood with a 400-ppm silver nanosuspension was carried out under an initial vacuum pressure of 0.07 MPa, followed by a pressure of 0.25 MPa for thirty minutes, before heat treatment. Heat treatment was carried out under hot air at three relatively mild temperatures, 145, 165, and 185 &deg, C. Results showed improvement of some properties in heat-treated wood at 145 &deg, C. This was indicative of the improving impact caused by hornification and irreversible hydrogen bonding in the course of water movements due to heat treatment, significant fluctuations in the intensities of FTIR spectra bands at 1750&ndash, 1500 cm&minus, 1 were corroborating evidence of chemical alterations in hemicellulose polymer. The high mass loss at temperature 185 &deg, C, and the extreme thermal degradation thereof, overcame the improving effects of hornification and formation of irreversible hydrogen bonds, consequently mechanical properties decreased significantly. Interaction of different elements involved made it hard to predict properties in specimens modified at 165 &deg, C. Impregnation of specimens with nanosilver suspension resulted in significant increase of mass loss in specimens heat-treated at 185 &deg, C, and significant fluctuations in properties of specimens heat-treated at 145 &deg, C.

This study aimed to assess the cryoprotectant effect of vacuum packaging (35 and 45 kPa) on cold preserved (0 °C and -18 °C) fillets of Yamú (Brycon amazonicus), during 5 days of storage. We analyzed the physicochemical and microbiological changes in the fillets during storage time. Yamú’s water holding capacity, nitrogenated bases content (TVB-N) and texture (N) were affected (p ≤ 0.05) by time and temperature. Bacterial colonies in fillets did not represent a risk for human health after five days of storage. In conclusion, vacuum packing positively (p ≤ 0.05) reduces the effect of cold over Yamú fillets properties. Resumo O objetivo deste trabalho foi avaliar o efeito crioprotetor de embalagens a vácuo (35 e 45 kPa) em filés de Yamú (Brycon amazonicus) conservados a frio (0 °C e -18 °C), durante cinco dias de armazenamento. As alterações físico-químicas e microbiológicas foram analisadas nos filés durante o armazenamento. A capacidade de retenção de água, o teor de base nitrogenada (BTV-N) e a textura (N) foram influenciados (p ≤ 0,05) pelo tempo e pela temperatura. Colônias bacterianas em filés não representaram risco à saúde humana após cinco dias de armazenamento. O uso de embalagem a vácuo apresentou efeito significativo positivo (p ≤ 0,05), reduzindo o efeito do frio sobre as propriedades dos filés.

In this work, date juices were concentrated at low temperature by Vacuum Membrane Distillation (VMD). Tests were conducted at fixed operating conditions (feed flowrate, 28 L/h; feed temperature, 28 °C; vacuum pressure, 4 mbar) on two commercial flat polypropylene membranes, different in pore size and thickness. Date concentrates (70 °Bx) were obtained starting from juices at 18 °Bx, and pure permeates (0 °Bx) were collected. The water vapour trans-membrane flux depended on membrane properties until a concentration of ~50 °Bx was reached; then, the resistance at the feed side controlled the process.

espanolEl objetivo de la investigacion fue evaluar las condiciones de proceso de fritura al vacio sobre la calidad de chips de papa (Solanum tuberosum) variedad Botella Roja, mediante un diseno central compuesto cara centrada ((=1), en funcion de las variables ∆T (Taceite - Tebullicion del agua) (40-60 °C), presion de vacio (30-70 kPa) y tiempo (3-7 min). La optimizacion experimental permitio fijar las variables de proceso: ∆T (40 °C), presion (46,70 kPa) y tiempo (5,04 min), y variables dependientes: humedad (6,0(0,8%bh), absorcion de aceite (19,9(1,2%), actividad de agua (0,450(0,01), indice de peroxidos (5,1(0,6 meqO2/kg), actividad antioxidante (2,2-diphenyl-1-picrylhydrazyl y 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (49,4(4,1 y 47,8(6,5 meq Trolox/100 g Solido Seco respectivamente)), fenoles totales (54,7(7,9 meq Acido Galico/100 g Solido Seco), color (L*: 66,2(1,2; a*:1,4(1,3 y b*:5,0(2,1) y fuerza de fractura (5,7(0,8 N). La fritura al vacio es un proceso que contribuye a mejorar la calidad fisicoquimica de chips de papa variedad Botella Roja. EnglishThe aim of the investigation was to evaluate the vacuum frying process conditions on the quality of potato chips (Solanum tuberosum) Botella Roja variety, using the response surface methodology, by a central design composed centered face ((=1), according to the variables Δ T (Toil - Twater boiling) (40 - 60 °C), vacuum pressure (30-70 kPa) and time (3 - 7 min). The experimental optimization allowed to fix the process variables: ΔT (40 °C), pressure (46.70 kPa) and time (5.04 min), and the dependent variables: moisture (6,0(0,8% bh), oil absorption (19,9(1,2%), water activity (0,454(0,015), peroxide index (5,1(0,6 meq O2/kg), antioxidant activity (2.2- diphenyl-1-picrylhydrazine and 2,2-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (49.4(4.1 and 47.8(6.5 meq Trolox / 100 g of dry solid respectively)), total phenols (54,7(7,9 meq AG/100 g of dry solid, color (L*: 66,2(1,2; a*:1,4(1,3 and b*:5,0(2,1) and fracture force (5,7(0,8 N). The vacuum frying is a process that contributes to improve the physicochemical quality of potato chips Botella Roja variety.

The objective of this work was to analyze the physical-chemical characteristics of the noni pulp and to evaluate the rehydration kinetics of the powder obtained after lyophilization of the fruit pulp. Lyophilization of the pulp was carried out at a vacuum pressure of 130 μHg with samples temperature of -21°C. Physico-chemical analyses of pH, soluble solids content (°Brix) and titratable acidity (g 100 g-1 citric acid) were performed and the Peleg and Weibull models were used to describe the rehydration kinetics. The physico-chemical characterization presented values in agreement with the limits established by the Brazilian legislation and the two equations used to adjust the behavior of rehydration kinetics were efficient.

Extraction of cell-free DNA (cfDNA), which exists at an extremely low concentration in plasma, is a critical process for either targeted-sensing or massive sequencing of DNAs. However, such small amount of DNA cannot be fully obtained without high-speed centrifugation (

Highlights • 16 batches of ginger slices were pretreated by VOS, VSON, VOD and control (untreated). • The variously pretreated ginger slices were then dried by infrared drying. • The metabolomes and other quality parameters of the dried samples were determined. • The VOS-pretreated samples exhibited superior quality characteristics over the rest. • The trend of significance for the various pretreatments: VOS > VSON > VOD > Control., We assessed the impact of selected pretreatment techniques, thus, vacuum-assisted osmotic dehydration (VOD), vacuum-assisted sonication (VSON) and vacuum-assisted osmosonication (VOS) on the metabolomes and quality characteristics of infrared-dried ginger slices. We found marked metabolome differences between the pretreated ginger samples, evidenced by differential amounts of 6-gingerol and 6-shogaol, total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activities. We also found distinct differences in the drying kinetics and sensory characteristics of the pretreated samples. Generally, VOS pretreatment gave the best outcomes. The VOS-pretreated samples contained the highest contents of the marker compounds, TPC, TFC and gave the best antioxidant activity. The VOS-pretreated samples also recorded the shortest drying time and exhibited the best sensory attributes. Overall, the general order observed was, VOS > VSON > VOD > control for all quality parameters examined. VOS pretreatment of ginger before drying therefore holds a great potential for large-scale industrial application.

A sludge dewatering method based on polyethylene glycol (PEG) solution dialysis effectively reduced the moisture content in sludge to under 60%, which realized the aim of deep dehydration. However, it remains difficult to apply to marketization and industrialization due to the limited influence range of dialysis. Therefore, this study develops a new sludge dewatering technology using the PEG solution dialysis method combined with vacuum pressure. By applying vacuum pressure to the dialysis process, the sludge structure is compacted, which reduces the internal voids between the sludge particles and promotes water that had not been removed to find suitable drainage channels to continue to discharge. The results showed that the dehydration effect of this method was observably improved as compared to single dialysis, and the influence range of dialysis significantly increased. Compared with 0 kPa, the influence range of dialysis at 100 kPa increased by 183%. X-ray computed tomography (X-ray CT) was used to establish the 3D reconstruction images of the sludge and analyze the change law of the sludge microstructure under different vacuum pressures. The relationships between the final moisture content and pore characteristics were obtained, which proved the effectiveness of the dehydration method using PEG solution dialysis combined with vacuum pressure. This study investigates the positive influence of vacuum pressure on dialysis dehydration, and further reveals the dewatering mechanism of this method during the sludge dialysis process. This study provides new insights for sludge volume reduction and propels the market-oriented and industrial application of sludge dialysis dewatering.

A molecular pump is always used as the main pump of the vacuum leak detection system because of its strong ability for pumping helium. But the pumping speed of a molecular pump is not enough for large vacuum chamber. A cryopump is a clean, oil-free and high pumping-speed vacuum pump. If a cryopump is used as the main pump of the vacuum leak detection system, the number of the pumps will decrease. This paper describes the experiments on vacuum leak detection system with cryopump as a main pump, and analyses the phenomena in the experiments. The results show that the cryopump decreased the vacuum pressure of the system significantly, but it had nearly no influence to the system sensitivity. The response time and the clean-up time of the leak detection system with only molecular pump were both 3 min. But the response time of the leak detection system with both molecular pump and cryopump was 10 min–20 min, and the clean-up time of the system was longer than an hour.

A mathematic model is developed for the perovskite-type mixed ionic-electronic conducting (MIEC) membrane, which makes it possible to simulate the process of oxygen separation in the U-shaped Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3 − δ hollow-fiber membrane. The model correlates the oxygen permeation flux to the measurable variables. The trends of calculated results for purge operation coincide well with the experimental data, therefore the model is considerable for flux prediction under vacuum operation. Higher oxygen separation efficiency can be achieved with vacuum operation than purge operation. Parameter study with vacuum operation reveals that oxygen permeation flux increases with higher vacuum levels, and vacuum pressure of around 1.013 × 10 3 Pa is the optimal. Also, vacuum operation on the lumen side is much more efficient to achieve higher oxygen permeation flux compared with compression mode on the shell side.

A layered-bed vacuum pressure swing adsorption (VPSA) process with a hybrid packing of Cu(I)AC and Cu(I)Y adsorbents was developed to recover CO from a low-concentration syngas mixture (2.4%CH4–32.3%CO–1.0%CO2–46.0%H2–18.3%N2). Prior to performing a sequential separation VPSA process design, the statical adsorption equilibrium isotherms of pure CH4, CO, CO2, H2, and N2 on two dissimilar improved copper-supported adsorbents of Cu(I)AC and Cu(I)Y were first determined under four different temperature values (293.15, 303.15, 313.15, and 323.15 K) with pressures up to 500 kPa. The experimental adsorption equilibrium data of the pure component were then proved to be well fitted by a Langmuir isotherm model. Further, multicomponent breakthrough curves were separately measured by experiments and simulations with a fixed-bed adsorption mathematical model to obtain a successful prediction for multicomponent adsorption dynamics and equilibrium. On the basis of these, a pilot-scale multibed VPSA simulation work with...

The aim of this study was to optimize the processing parameters of pulse mode microwave-vacuum drying of germinated green and red lentils (CDC Greenland and CDC Maxim) and investigate the changes in their total phenolic content (TPC), total antioxidant activity (TAA) and in-vitro starch digestibility (SD). The lentils were germinated for 5 days and dried by a pulse mode microwave-vacuum method, using 2 s to 8 s out of 10 s pulsed mode at 2000W microwave power and varying the vacuum pressure level between 15 and 45 kPa. In-vitro starch digestibility increased significantly with increased microwave power level. The TPC and TAA appeared to vary distinctively in the two varieties of selected lentils. Vacuum pressure levels did not significantly (p>0.05) affect any responses. Green lentils could be dried at 8 s microwave power and 45 kPa vacuum pressure and red lentils could be dried at 5.5 s microwave power and 42.19 kPa vacuum pressure. The microwave-vacuum drying showed great potential for the drying of germinated lentils.

Summary Coloured apple discs containing black carrot concentrate (BCC), calcium lactate and lactic acid were formulated and produced as a new functional fresh fruit product using vacuum impregnation. Sensory test was conducted to select the most preferred impregnation formulation containing an addition of 0.0%, 0.4%, 0.8% and 1.2% BCC, 1.5%, 3.0% and 4.5% calcium lactate and 2.0%, 3.0% and 4.0% lactic acid. Results indicated that the formulation with the addition of 3% Ca-lactate, 3% lactic acid and 0.8% BCC within 0.2 m mannitol solution was significantly preferred. The optimum vacuum pressure (211 mm Hg), vacuum time (3 min) and restoration time (20 min) according to highest colorant transfer, while the minimum cellular disruption occurs were estimated using response surface methodology. The use of Ca-lactate and BCC contributed the treated apple to resemble untreated apple properties in terms of texture, total phenolic, total flavonoid contents and antioxidant capacity.

Vacuum impregnation was used to improve the quality attributes of fresh-cut papayas. Vacuum pressure of 5 kPa was applied for 5 min, then calcium lactate (1%, w/w) and pectin methylesterase (PME) (15 U/ml), alone and in combinations (calcium lactate plus PME), were vacuum impregnated into fresh-cut papaya cubes. Papaya cubes were stored at 4 °C, and the quality of fresh-cut papaya was studied at intervals for 8 days. The hardness and chewiness levels of fresh-cut papayas that were treated with calcium lactate and PME were 8.02 and 7.83 times of untreated fresh-cut papayas at day 8, respectively. After vacuum impregnation, colour of fresh-cut papayas changed significantly (P

Potato chips can be considered as an ideal carrier for targeted nutrient/s delivery as mostly consumed by the vulnerable group (children and teen agers). The present study was planned to fortifiy potato chips with calcium (Calcium lactate) and zinc (Zinc sulphate) using vacuum impregnation technique. At about 70–80 mm Hg vacuum pressure, maximum level of impregnation of both the minerals was achieved. Results showed that after optimization, calcium lactate at 4.81%, zinc sulphate at 0.72%, and vacuum of 33.53 mm Hg with restoration period of 19.52 min can fortify potato chips that can fulfil 10 and 21% need of calcium and zinc, respectively of targeted group (age 4–17 years). The present research work has shown that through this technique, fortification can be done in potato chips which are generally considered as a poor source of minerals. Further to make potato chips more fit to health conscious consumers, rather frying microwaving was done to develop mineral fortified low fat potato chips.

We report a procedure using a pressure-controllable flute needle to remove subfoveal retention of perfluorocarbon liquid (PFCL) under silicone oil. With a two-port pars plana approach, we used a 27-gauge dental injection needle to create a retinotomy at the farthest edge of the PFCL bubble from the fovea. A 27-gauge flute needle was then inserted into the edge of the subfoveal PFCL to aspirate it with vacuum pressure. Three patients with subfoveal retained PFCL were treated by this procedure within silicone oil tamponade 1 month after the first operation. They promptly underwent successful removal of the PFCL with postoperative retinal reattachment and good visual outcome. This procedure allows safe and early treatment for subfoveal retained PFCL. Many medical institutions around the world could implement this procedure using common dental injection needles and flute needles.

In this research, ammonia evaporation capacity under atmospheric and vacuum pressure conditions, as well as distillation capacity of different concentrations of landfill leachates, were evaluated. Simple evaporation and vacuum pressure evaporation tests showed high NH3–N removal efficiencies, ranging from 95% to 98% for raw landfill leachates, indicating that vacuum pressure would not be necessary during ammonia removal and recovery processes when applying temperature of 300 °C. Distillations tests also showed the promising NH3–N recovery potential in ultra-concentrated leachates (over 100 gNH3-N/L) in the order of 91%–94% in few minutes, evaporating a small portion of landfill leachate. The results presented encourages the recovery of ammonia from landfill leachate and its industrial and agricultural, highlighting its feasibility as well as simultaneously preventing the ammonia release to water bodies or the atmosphere.

A four-bed and six-bed vacuum pressure swing adsorption (VPSA) process with silical gel were proposed to separate and purify N2O from adipic acid tail gas (N2O/N2/O2 = 0.3933/0.5657/0.041 mol%) in nylon plants and then the N2O could be rectified to produce ultra-high purity N2O. The four-bed VPSA process was developed to study the relationship between vacuum pressure and simulation performances, the resulting recovery of N2O exceeds 90% with a purity over 95%. Meanwhile, the six-bed process was designed to explore the effects of vacuum and feed flow rate. The results indicated that a 95.55% purity N2O stream is attained for a process N2O recovery of 97.45%, when the feed flow rate was 1434.8 NL/s and vacuum pressure was 0.247 bar and N2O energy was 4.95 KJ/mol N2O respectively.

Cryogenic piping system is a delicate product. If it is not designed properly, i.e., without considering region specific weather condition, vapourisation will occur at undesirable rate while cryogenic fluid flows through the pipeline. In this work, optimum design for a cryogenic piping system has been explored. To identify existing design limitations as well as customer priorities, quality function deployment has been employed. Data have been collected from local customers and experts through questionnaire-based survey. Double-concentric-pipes type construction with inner pipe diameter of 21.34-33.40 mm and outer pipe diameter of 88.90-193.68 mm has been considered. Four potential insulating mediums; multilayer insulation, vacuum, polyethylene foam, and perlite have been investigated. Multilayer insulation thickness and vacuum pressure have been varied from 6-30 mm and 10−5−5 mbar respectively. Results reveal that use of multilayer insulation accompanied by vacuum pressure of 10−4 mbar ensures optimum performance with optimum insulation thickness of 20 mm.

Carbon nanofiber-reinforced polymer aerogels have been successfully synthesized by means of a freeze-drying process. The influence of the different operation conditions on both the process efficiency and the aerogel physical properties has been evaluated. Morphology, porosity and conductivity of the resulting carbon nanofiber-reinforced polymer aerogels were investigated. Their density and porosity increased when the freezing time decreased. However, the porosity of the carbon nanofiber-reinforced polymer aerogels increased and when both the vacuum pressure and the freeze-drying temperature increased, respectively. No clear effect of the operating conditions on the thermal conductivity of the aerogels synthesized was detected, ranging from 0.037 to 0.069 W/m K. The low values of thermal conductivity obtained suggest that these materials could be used for building insulation purposes. In addition, the addition of carbon nanofibers allowed to increase the mechanical resistance of the final product to be used as building insulation materials to reduce the energy consumption., Se han sintetizado con éxito aerogeles poliméricos reforzados con nanofibras de carbono mediante un proceso de liofilización. Se ha evaluado la influencia de las diferentes condiciones de operación tanto en la eficiencia del proceso como en las propiedades físicas del aerogel. Se investigó la morfología, porosidad y conductividad de los aerogeles poliméricos reforzados con nanofibras de carbono resultantes. Su densidad y porosidad aumentaron al disminuir el tiempo de congelación. Sin embargo, la porosidad de los aerogeles poliméricos reforzados con nanofibras de carbono aumentó y cuando la presión de vacío y la temperatura de liofilización aumentaron, respectivamente. No se detectó un efecto claro de las condiciones de operación sobre la conductividad térmica de los aerogeles sintetizados, que osciló entre 0,037 y 0,069 W/m K. Los bajos valores de conductividad térmica obtenidos sugieren que estos materiales podrían utilizarse para el aislamiento de edificios. Además, la adición de nanofibras de carbono permitió aumentar la resistencia mecánica del producto final para ser utilizado como material de aislamiento de edificios para reducir el consumo de energía.

Hydrogel patterning methods are widely used for cell patterning because they offer better long-term stability than protein patterning methods such as micro-contact printing, but conventional hydrogel patterning methods require special apparatuses such as a laser or an electron beam lithography system or they have complicated chemical operations which prevent their practical use in biological laboratories. A simple method was developed to cast a hydrogel solution without external power sources using a polydimethylsiloxane (PDMS) mold with micro-channels. This study employed “the accumulation of vacuum pressure” in a degassed lump of PDMS as a driving force for introducing agarose solution into the micro-channels. Sufficient vacuum pressure could be accumulated within 1 h in the PDMS elastomer that was acting as a vacuum tank, and 2 w/v% agarose solution could be aspirated into the micro-channels with widths from 100 to 2000 μm and a height of 19 μm, fully filling them. After the gelation and dehydration of agarose solution in the micro-channels, the patterns of agarose gel on the channels were successfully cast with a 90%-width accuracy. By using the repellency of agarose gel toward cell adhesion, patterned cultures of myoblasts and cortical neurons were successfully prepared. This technique is expected to be useful in repellency-guided cell patterning for various types of cells, with applications to cell–cell interactions and axon guidance.

Motors with higher efficiency and smaller size are the premise for producing higher performance electrical products and achieving an energy-saving world, so the motors should be fabricated with Vacuum Pressure Impregnation (VPI) technique and the matrices for the motors should be high performance resins that have higher thermal resistance and lower dielectric loss. However, available resins for common motors do not simultaneously have VPI processing characteristics, high thermal resistance and low dielectric loss. Herein, based on unsaturated polyester (UP), the common VPI resin for which the thermally resistant level is as low as F level (155 °C), a unique high performance resin is developed by co-polymerizing UP resin with a novel benzyl alcohol terminated hyperbranched polysiloxane (Vi-HPSi). The structure and integrated performances of Vi-HPSi/UP resins were intensively studied. Results show that Vi-HPSi/UP resin not only meets the strict processing requirements of VPI technique, but also has better curing features, thus endowing Vi-HPSi/UP resins with higher crosslinking density and reduced free volume than the UP resin. In addition, compared with the UP resin, Vi-HPSi/UP resins have much better toughness and bond strength, greatly improved thermal stability, and reduced dielectric loss. Typically, for the Vi-HPSi/UP resin with 20 wt% Vi-HPSi (20Vi-HPSi/UP), its initial degradation temperature is as high as 331 °C, about 80 °C higher than that of the UP resin, and this is also the highest value among modified UP resins reported; while the dielectric loss of 20Vi-HPSi/UP is about 0.62 times of that of the UP resin. These attractive performances demonstrate that the Vi-HPSi/UP resin has great potential for fabricating new generation motors with higher efficiency for cutting-edge applications.

Background Unevenness in softening of the plastic sheet leads to a decrease in the mouthguard thickness during thermoforming. In this study, we examined the heating methods for reducing unevenness when softening mouthguard sheets during vacuum–pressure formation. Materials and methods Ethylene vinyl acetate mouthguard sheets and olefin copolymer sheets (thickness: 4.0 mm) were used. The following three heating conditions were compared: condition A—the sheet was molded when it sagged 15 mm from the sheet frame (under normal condition); condition B—the heater was turned off when the sheet sagged by 10 mm from the frame, followed by the sheet molding when the sagging reached 15 mm below the frame; and condition C—the sheet was inverted after heating when the sheet sagged 10 mm and was molded when the sagging reached 15 mm below the frame. The sheet was heated and pressed over the model using a vacuum–pressure machine; then, 10 s of vacuum forming and 2 min of pressure molding were applied. The sheet temperatures were measured using a radiation thermometer. Thickness of the fabricated sheets was determined for the incisal and the molar portion using a measuring device. Thickness data for each condition were analyzed by one-way anova followed by Bonferroni's multiple comparison tests. Results On both sheets, condition B was smallest for temperature difference between the heated and the non-heated surface, and thicknesses after molding were greatest at all measuring portions. Conclusion By comparing changes in sheet temperatures at molding and variation in thicknesses when applying the heating method using a vacuum–pressure molding machine, we found that reduced unevenness in sheet softening occurred when the heater was turned off when the sag distance of the sheet was 5 mm less than the conventional molding, and then, the sheet was pressed when the conventional sag distance was reached.