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The scientific task to improve energy efficiency and ensure the process of vacuum regime stabilization in the operation of milking machines has been solved. A mathematical model of the process of functioning of the servo control system of a rotary plate vacuum pump was built; the numerical modeling of its workflow was carried out. This paper reports the results of experimental studies on the influence of the regime parameters of the rotary plate vacuum pump on the efficiency of its operation, as well as the results of experimental research on the servo control system for the rotary plate vacuum pump. The operational process of the rotary plate vacuum pump HB-1200 for a milking machine was investigated. The influence of mode parameters (rotor speed n and vacuum pressure P) on the performance of the vacuum pump, Qa, vacuum pressure fluctuation, ΔP, and the power consumption of the vacuum pump drive, Np, has been determined. The servo control system of the rotary plate vacuum pump was experimentally investigated based on the developed algorithms of its operation. In a generally accepted algorithm, vacuum fluctuation increases with increasing an airflow rate: at ΔQa=45l/min – ΔP=2.3kPa; at ΔQa=90l/min – ΔP=4.6kPa; at ΔQa=135l/min – ΔP=6.4kPa. Unlike the generally accepted one, the developed algorithm enables a stable vacuum mode with the largest vacuum fluctuation being ΔP=2.4kPa. For the first time, the functional dependence of the influence of the regime parameters of the rotary plate vacuum pump with its automatic servo control system on the stability of the vacuum regime of a milk-vacuum system in the milking machine was established. The results can be applied when improving milking machines in terms of ensuring the stabilization process of the vacuum regime.

We present a microfluidic technique that shrinks lipidstabilized microbubbles from O(100) to O(1) µm in diameter–the size that is desirable in applications as ultrasound contrast agents. We achieve microbubble shrinkage by utilizing vacuum channels that are adjacent to the microfluidic flow channels to extract air from the microbubbles. We tune a single parameter, the vacuum pressure, to accurately control the final microbubble size. Finally, we demonstrate that the resulting O(1) µm diameter microbubbles have similar stability to microfluidics generated microbubbles that are not exposed to vacuum shrinkage. We anticipate that, with additional scale-up, this simple approach to shrink microbubbles generated microfluidically will be desirable in ultrasound imaging and therapeutics applications.

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.

Introduction Given the high morbidity and mortality of stroke, there remains a demand for techniques that provide rapid and safe intervention while improving time to recanalization. The direct aspiration first-pass technique (ADAPT) uses force and aspiration for clot removal without the aid of separators or retrievers. In this study, we compare the force and aspiration qualities of commercially available catheters. Methods Four different catheters with varying inner diameters were set up in a bench top model to test catheter tip pressure and flow rate. Catheter tip pressure was measured by attaching the catheter to a vacuum pressure gauge and an aspiration pump. The flow rate was calculated by measuring the volume of room temperature water aspirated through each catheter over a given time. Results The Microvention Sofia catheter generated the greatest tip force (21.32 g), and the Stryker AXS Catalyst 6 catheter generated the smallest tip force (15.88 g). The Penumbra ACE 068 catheter and Medtronic ARC catheter measured 20.87 g and 16.78 g respectively. The ACE 068 had highest rate of aspiration at 289 mL/min, and the Catalyst 6 catheter had the lowest rate at 214. The Microvention Sofia catheter had the second highest rate while the ARC had the third highest rate, measuring 285 mL/min and 256 mL/min, respectively. Conclusions When using the ADAPT technique, knowledge of the tip force and catheter flow rate of newer catheters with larger distal inner diameters may guide selection of aspiration catheters. While this study demonstrates differences in tip force and flow rate of different commercially available catheters, clinical translation will require further testing and evaluation.

This article demonstrates the results of experimental research one of the pulsators. Its main difference from others is a pneumatic electromagnetic pulsator in combination with a collector. Therefore, this article describes in detail the process of studying the pulsator. The planned experiment was carried out on by Factorial experiments with multiple factors. The influence of factors (the ripple frequency n, the milk ejection q and the ratio between strokes t/T) on the vacuum pressure in the inter wall chamber of teat cups was studied. The regression equation of the dependence response criterion on factors is modeled. This dependence is demonstrated graphically. Also there is a contour graph which is for more detailed information. Article in English. Pneumatinio elektromagnetinio pulsatoriaus su kolektoriumi tyrimo rezultatai Santrauka Šiame straipsnyje yra pateikti vieno iš pulsatoriaus eksperimentinio tyrimo rezultatai. Esminis išskirtinis šio pulsatoriaus bruožas – kolektoriaus buvimas. Buvo atliktas išsamus faktorinis eksperimentas. Tiriamas tokių faktorių, kaip pulsacijų dažnio n, pieno išskyrimo q ir taktų santykio t/T, poveikis vakuuminiam spaudimui vidinėje melžimo mašinos kameros sienelėje. Buvo suformuluota regresinė lygtis, vaizduojanti faktorių priklausomybės atsako kriterijų. Ši priklausomybė pavaizduota grafiškai. Taip pat yra pridėtas kontūrinis grafikas detalesnei informacijai pademonstruoti. Reikšminiai žodžiai: melžimo mašina, pulsatorius, elektromagnetinis pulsatorius, kolektorius, vakuuminis spaudimas, pulsacijos dažnis, išmesta pieno masė, faktoriai.

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.

Human milk extraction from the breast is affected by the infant's oral activities. Natural suckling by the infant includes both intraoral vacuum and peripheral oral compression during breastfeeding. However, the contribution of each of these motions to milk extraction at the outlet and at the duct bifurcations is unclear. In this work, we investigated the flow field in a lactating breast model considering bifurcated milk ducts and multiphase breast-infant interactions. A bio-inspired breastfeeding simulator device was utilized to mimic an infant's oral feeding mechanism during breastfeeding and extract the human milk-mimicking Fluid from the transparent and elastic lactating breast phantom during experiments. Using a particle image velocimetry system, we found that the oscillatory flow under vacuum pressure provides a higher velocity field at the outlet compared to that when an infant applies both vacuum and oral compression pressures. Additionally, the intraoral vacuum coordinated with the oral peripheral compression causes stronger vorticities and secondary flows at the adjunction of the bifurcated ducts than the vacuum-only case. Vacuum-only extraction yields an increase in flow velocity at the outlet and could be one of the reasons for nipple pain, whereas infant's oral activities on the breast generated more vortices in the milk duct adjunctions and might cause milk duct clogs. This phenomenon is rationalized based on the validation of a previous in vivo clinical study of milk production compared between commercial pumps and infant suckling. The fact that milk consumption of vacuum-only extraction is less than that of vacuum plus oral compression further explains the effectiveness of applying a natural suckling pattern in human lactation.

Prefabricated vertical drains (PVDs) and deep cement mixing (DCM) columns combined ground improvement with a vacuum pressure for embankment construction on soft clay deposits has advantages, such as limiting embankment load induced deformation of adjacent areas and reducing total ground improvement cost. However, for design this kind of soft ground improvement, there are no methods for estimating amount of ground deformations as well as maximum tensile stress in the DCM columns. A series finite element analyses (FEA) were carried out to investigate the performance of embankments on combined PVD together with a vacuum pressure and DCM column improved soft deposit. Based on the results of FEA, explicit method for calculating ground settlement under the center of embankments, graphic methods for predicting maximum tensile stress in the column and maximum lateral displacement under the toe of embankments have been established. It is suggested that these methods can be useful tools for design this kind of combined soft ground improvement, and a working example has been demonstrated.

N,N′-Bis(n-octyl)-1,6-dicyanoperylene-3,4:9,10-bis(dicarboximide) (PDI8-CN2) organic thin film transistors (OTFTs) were found to exhibit a remarkable change of electrical conductivity when characterized under vacuum pressure in the range from 70 Pa (low vacuum) to 100 kPa (atmosphere). A similar phenomenon was also observed on pentacene-based OTFTs but not on two-dimensional layered MoS2 TFTs. The mechanism to interpret a vacuum pressure response of organic thin film transistors is assumed to be the miniscule change of intermolecular distances under applied pressures. The values of variation of intermolecular distances are theoretically calculated based on a hopping model of the Marcus transfer rate. In addition, the Young's modulus of the PDI8-CN2 thin film evaluated through this model agrees well with the experimental values measured by atomic force microscopy (AFM) characterization using a Peakforce Quantitative NanoMechanics (QNM) mode.

Pitting initiation and stable propagation behaviors of 2205 duplex stainless steel were investigated in the hot concentrated seawater under vacuum pressures by potentiostatic polarization. Both applied potentials and vacuum pressures greatly influence the pitting corrosion. Higher potentials lead to much faster stable pitting initiation and growth rates in both static (101.3 kPa) and dynamic (28.4 kPa) solutions. The pressure reduction can also accelerate the pitting initiation rate. However, the boiling of solution can influence the pitting propagation mechanism. The dynamic actions of boiling bubbles are unfavorable to the pit propagation and result in the formation of relatively smooth pit bottom without secondary pits.

A large-strain consolidation model incorporating vacuum pressure growth propagation (VPGP) under vacuum preloading is proposed. A finite-difference method was developed to predict the vacuum consolidation behaviour. The proposed model can be degenerated into the existing model when the vacuum pressure growth factor reaches 10/day. The rationality of the proposed model was verified and compared with experimental results. The effect of VPGP on the consolidation behaviour of two typical soils was then analysed. A growth in vacuum pressure has a significant effect on consolidation, especially for a growth factor in the range 0–0.5/day. The radial and vertical propagation of vacuum pressure obviously slowed down the dissipation of excess pore-water pressure (EPWP). The maximum difference reached 48% and 37.5% when the radial attenuation factor and the vertical residual factor were in the range 0–0.1/cm and 0.25–1.00, respectively. The maximum value of the EPWP difference of two typical soils reached 65 kPa.

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

Coal-based H2 generation has abruptly increased in recent years. The PSA-VPSA-SC process is the matured and standard framework for H2 purification and CO2 capture in many existing plants, including normal and vacuum pressure swing adsorption units in series (PSA-VPSA), and shallow condensation unit (SC). However, this standard process is frequently subjected to low H2 recovery ratio and high purification cost. In this work, H2-selective and CO2-selective membrane units, i.e., HM and CO2M, are attempted to support the standard process and ameliorate constraints. In the beginning, HM unit is arranged after VPSA to enhance H2 recovery from the decarbonized stream, i.e., the PSA-VPSA-SC/HM process. As a result, H2 recovery ratio can be enhanced significantly from 83% to 98%. In the following, VPSA is replaced with CO2M unit to reduce investment and operation cost, i.e., the PSA-CO2M-SC/HM process. Accordingly, the specific purification cost is diminished from 33.46 to 32.02 USD·(103 m3 H2)−1, saved by 4.3%, meanwhile the construction cost is falling back and just a little higher than that for the standard process. In the end, another CO2M unit is launched before PSA, i.e., the CO2M-PSA-CO2M-SC/HM process, which could unbundle CO2 enrichment partially from H2 purification, and then save more investment and operation cost. In comparison with the standard process, this ultimate retrofitted process can be superior in all the three crucial indices, i.e., recovery ratio, investment, and specific purification cost. On the whole, coal-based H2 generation can be ameliorated significantly through high efficient H2-selective and CO2-selective membrane units.

This paper aims to establish an analytical model on vacuum consolidation of dredged slurry treated by PVD with special considerations on the clogging effects. A series of laboratory tests have been conducted to characterize the temporal/spatial variations of the clogging zone and the vacuum pressure in soil. Based on the nonlinear relationship between the compressibility, the permeability and the void ratio (e-p and e-k curves), an analytical model incorporating the clogging zone was proposed and solved considering the nonlinear attenuation of the vacuum pressure. The solution was verified and validated by comparing with published data and field test results, respectively. Parametric studies reveal that the clogging significantly slows down the consolidation rate, and thus reduces the final degree of consolidation of the dredged slurry.

This study investigates the reduction of groundwater level in the soil deposit below the ground surface under vacuum consolidation. Theoretically, when the applied vacuum pressure is less than the air-entry value (AEV) of the soil deposit, the deposit will be in a saturated state and the groundwater level in the pre-fabricated vertical drains (PVDs) will not go below the ground surface during the vacuum consolidation process. In this case, the groundwater level is not a phreatic water level. If the applied vacuum pressure is larger than the AEV of the soil, part of the soil deposit can become unsaturated and the groundwater level in the PVDs can go below the ground surface. Further, the results of a large-scale vacuum consolidation model test using clay confirmed that during the consolidation process, the water level in the mini-PVD was always above the top surface of the model ground. Therefore, an attempt to measure the groundwater level in a vacuum consolidation area composed of clay deposits may not be worthwhile.

Alat tanam benih langsung atau yang biasa disingkat ATABELA telah umum digunakan pada budidaya padi di Indonesia. Salah satu masalah yang sering terjadi pada penggunaan alat ini yaitu, tidak konsistennya jumlah benih yang dikeluarkan. Disamping itu benih yang dikeluarkan biasanya lebih dari tiga benih, sehingga dapat menimbulkan persaingan dalam proses pertumbuhannya. Oleh karena itu perlu dikembangkan alat tanam benih langsung yang dosis benihnya presisi. Penelitian ini bertujuan untuk merancang aplikator alat tanam benih padi langsung dengan penjatuhan benih memanfaatkan tekanan vakum. Tujaun lainnya yaitu mengetahui tekanan yang dapat dihasilkan serta kecepatan maju yang dibutuhkan untuk menghasilkan tekanan vakum yang. Langkah awal dari penelitian ini yaitu mengidentifikasi tekanan yang dibutuhkan untuk memindahkan benih, kemudian membuat rancangan alat berdasarkan data tekanan tersebut. Pengujian dilakukan menggunakan motor DC sebagai pengganti putaran roda untuk mengetahui kecepatan maju yang dibutuhkan untuk memperoleh tekanan yang dibutuhkan. Kadar air dari benih yang digunakan 22.71 % dan tekanan yang dibutuhkan 97 kPa (4 kPa di bawah tekanan standar atmosfer) kecepatan maju yang dibutuhkan 2.5 m/s sehingga perlu dilakukan modifikasi pada perbandingan pulley roda dan poros penggerak.

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.

Prefabricated horizontal drain (PHD) assisted by vacuum pressure has been used in practice to accelerate the consolidation process of dredged soft mud. However, very few studies have investigated t...

In order to obtain pumpkin chips, hot air drying (HAD), freeze-drying (FD), combinations of hot air drying + explosive puffing drying (HAD + EPD) and freeze-drying + explosive puffing drying (FD + EPD) were studied and, the impacts of various methods and conditions (temperature, vacuum pressure and decreased the moisture content level after pre-drying) on the physical, antioxidant and textural properties of pumpkin slices have been examined.The best texture attributes, the highest rehydration ratio (RR), the highest volumetric expansion (VE), and the lowest bulk density were obtained from FD + EPD products. Otherwise, when FD samples were compared with FD + EPD ones, it was clearly seen that higher retention of total phenolic content, antioxidant capacity, total carotenoids and a better color quality were obtained. However, the combination of FD + EPD allows drying at a slightly shorter processing time that is compared to a single FD. FD + EPD products provided the highest crispness when it is compared with HAD + EPD. This fact indicated that the pre-drying method (FD) and the reduction of moisture level had a major impact on textural properties. Consequently, the FD + EPD combination proved that it is a more promising process when it was compared to other drying techniques in order to produce nutritious pumpkin chips., Scientific Research Projects of Ege UniversityEge University [BAP FLP-2018-20443], This research was supported by the Scientific Research Projects of Ege University (BAP FLP-2018-20443). The authors thank to the students Deniz Arc, Huseyin Tuncer and Ahmet Gurhan Akcan for lab support.

BackgroundANA Advanced Neurovascular Access provides a novel funnel component designed to reduce clot fragmentation and facilitate retrieval in combination with stent-retrievers (SRs) in stroke patients by restricting flow and limiting clot shaving. In previous publications ANA presented excellent in vitro/in vivo efficacy data, especially with fibrin-rich hard clots. We aimed to determine the main physical property responsible for these results, namely suction force versus aspiration flow.MethodsWe evaluated in a bench model the suction force and flow generated by ANA and compared them to other neurovascular catheters combined with a SR (Solitaire). Aspiration flow was evaluated with a flow rate sensor while applying vacuum pressure with a pump. Suction force was determined using a tensile strength testing machine and a purposely designed tool that completely seals the device tip simulating complete occlusion by a hard clot. Suction force was defined as the force needed to separate the device from the clot under aspiration. All experiments were repeated five times, and mean values used for comparisons.ResultsAspiration flow increased with the inner diameter of the device: ANA 1.85±0.04 mL/s, ACE68 3.74±0.05 mL/s, and 8F-Flowgate2 5.96±0.30 mL/s (PConclusionDespite lower in vitro aspiration flow, the ANA design showed a substantially higher suction force than other thrombectomy devices.

Herbal industries are facing challenges while processing the herbal leaves. Herbal leaves are processed using various methods such as convection drying, chemical drying, vacuum drying, microwave drying, etc. The common issues encountered during the time of drying the herbal leaves are lost in phytochemicals, nutrients and colour. Heat pump drying is an important method by which the drying can be made without influencing of environmental condition and by controlling the drying properties without loss in phytochemicals, nutrients and colour. In this proposed work the experimental device, namely closed-loop heat pump dryer is designed and developed for conducting experiments. For this study, Moringa leaves were considered as herbal leaves. The vacuum is introduced in the heat pump dryer and the Moisture Removal Rate (MRR) is calculated under this condition. The experiments were conducted with vacuum pressures of 0.9 & 0.8 bar and the air velocities of 1.1 m/s & 1.4 m/s respectively. In this study, the experiments were conducted under the above-said conditions for several periods with temperature transients. Based on the experimental study it is observed that the moisture removal rate is increased significantly under low pressure with high temperature and velocity.

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.

In this study, a new design of photovoltaic thermal (PV/T) collector is proposed. This design uses a vacuum layer above the silicon wafer and not exists in the traditional PV/T collector. This layer is used to decrease the heat loss from the top surface of the PV/T collector. The analysis is conducted using a 3D thermal modeling. The new collector design with the vacuum layer achieved a 26.6% increase in the thermal power while keeping the electrical the same at Reynolds number of 50 and solar radiation of 1000 W/m2. In addition, the degradation of the vacuum pressure slightly influence the thermal performance while increasing the vacuum pressure from 0.01 Pa to 10 Pa. While further increase in the vacuum pressure from 10 Pa to 1.013×105 Pa substantially decreases the gained thermal power with insignificant increase in the electrical power.

This paper presents a hybrid-approach based on the establishment of a relationship between diagnostic signals, vacuum pressure and contact erosion of vacuum circuit breakers (VCBs). The signals used for this real-time diagnosis comprise of the level of chopped-current, dielectric strength, and the field emission current. The proposed approach has been verified against authentic experiments and the results indicate an acceptable agreement between the estimated values by approach and experiments.

The aim of this study was to examine the drying kinetics of pears (Pyrus communis L.) with and without vacuum impregnation and under the different temperature by using tray dryer. Vacuum impregnation were applied to the the pears (15 mm thickness, 65 mm outer and 20 mm inner dimensions respectively) with the conditions of 50⁰ Brix impregnation solution concentration, 225 mbar vacuum pressure and 45 min vacuum time. Drying process was carried out at temperatures of 55, 65 and 75°C. Drying time of non-vacuum impregnated pears was determined 640, 500 and 340 min and vacuum impregnated pears was determined 700, 540 and 560 min respectively. Page, Exponential, Henderson and Pabis, Diffusion Approach were examined for testing the drying kinetics. Experimental values are in accordance with the expected values resulted Page and Difussion models of with and without vacuum impregnated pears. Effective diffusion coefficient (Deff) was varying 2.74×10-11 to 7.31×10-11 m2/s. m2/s with respect to the drying temperatures. The activation energy for the non-vacuum impregnated and vacuum impregnated pears was 32.93 kJ / mol and 24.25 kJ / mol, respectively.

The use of seeders with pneumatic distribution systems is increasingly demanding for plantation of corn crop. Knowledge about the operation and adjustments of the components of agricultural machines is fundamental to increase the good distribution of plants and to ensure higher productivity. The main goal of this research was to evaluate the influence of the size of the corn seed sieve under different vacuum pressure regulations on a pneumatic distribution system, to understand the longitudinal uniformity of the plants, as well as the final and individual productivity per plant. The vSet® (Precision Planting®) pneumatic distribution system equipped with 4 corn seed sieves (C1, C4, R1, and R4) subjected to 4 different vacuum pressure adjustments (7, 12, 17 and 22 in H2O-1) was applied as treatments on corn hybrid 30F53VYH. The design used was that of randomized blocks, with subdivided plots and 4 replications. The main plot presented the vacuum pressures and the subplots presented the sieves, each composed of two sowing lines of 20 m in length. The results showed that low vacuum pressure resulted in increased unevenness between corn spacings and consequently lower yield. Smaller sieves showed less gaps and higher percentages of normal spacing. The larger sieves showed higher standard deviation and more gaps. Regular and uneven gaps provided a higher number of grains per row, higher number of grains per corn spike and a higher grain yield per corn spike.

Bu çalışmada, sıcak hava ile kurutma (50, 60, 70 °C ve 1.8 m/s), mikrodalga kurutma (180, 360, 540 W) ve dondurarak kurutma (0.2, 0.15, 0.1 mbar) olmak üzere üç farklı kuruma yöntemi deneysel olarak incelenmiş ve yağı azaltılmış beyaz peynirin (RFWC) kurutma kinetiği belirlenmiştir. Mikrodalga kurutma yönteminde işlem süresi, RFWC için sıcak havayla kurutma ve dondurarak kurutma yöntemlerinden önemli ölçüde daha kısadır. RFWC'nin kuruma kinetiğini temsil eden en yüksek R2 ve en düşük RMSE ve χ2 değerlerini hedefleyen en uygun kurutma modelini belirlemek için yarı deneysel modeller uygulanmıştır. Farklı kurutma yöntemleri için efektif difüzyon katsayısı değerleri 1.521 x 10-9 ile 4.432 x 10-8 m2/s arasında değişmiştir. Sıcaklık, mikrodalga gücü ve vakum basıncının artırılmasıyla efektif difüzyon katsayısı değerleri artmıştır. Aktivasyon enerjisi değerleri sıcak havayla kurutma için 12.421 kJ/mol ve mikrodalga kurutma için 5.599 W/ g olarak belirlenmiştir., In the current study, three different drying methods, including hot air drying (50, 60, 70 °C and 1.8 m/s), microwave drying (180, 360, 540 W) and freeze-drying (0.2, 0.15, 0.1 mbar) were experimentally studied and the drying kinetics of reduced-fat white cheese (RFWC) were determined. Microwave drying process time was significantly shorter than hot air drying and freeze-drying for RFWC. Semi-empirical models were applied to determine the most appropriate drying model targeting the highest R2 and the lowest RMSE and χ2 values representing the drying kinetics of RFWC. The effective diffusion coefficient values for different drying methods varied from 1.521 x 10-9 to 4.432 x 10-8 m2/s. Through increasing the temperature, microwave power, and vacuum pressure, effective diffusion coefficient values increased. The activation energy values were determined as 12.421 kJ/mol for hot air drying and 5.599 W/g for microwave drying.

In current work, the effects of drying temperature (60, 65, 70, and 75 °C), vacuum pressure duration (VPD; 6, 9, 12, and 15 min), and ambient pressure duration (APD; 2, 3, and 4 min) on drying kine...

This paper presents a case study on the improvement of thick marine deposits. A new method that combines vacuum pressure and surcharge load with no need for a sand cushion is proposed and evaluated...

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.

Horizontal spacing of horizontal extraction gas wells can be designed to achieve a 90% pumping rate of the total generated landfill gas (LFG) from given waste properties (viz: gas permeability, landfill gas generation and non-homogeneity with depth), cover characteristics and vacuum pressure. However, cover characteristics and vacuum pressure are also important design parameters and different combinations of them result in different distributions of gas pressure in the waste, some of which would induce problematic air intrusion while others might pose threat to cover stability. This paper uses the maximum gas pressure directly below cover to distinguish these combinations, and provides the first study of the effects of the above parameters on potential outcomes. The ability of the overlying cover to resist LFG emission from the landfilled waste is suggested not to exceed a critical value, otherwise the maximum gas pressure below it would become at least 1 kPa larger than atmospheric pressure. A design formula for this critical value is proposed with respect to typical values of waste properties, vacuum pressure and the buried depth of horizontal wells in wide ranges. Together with consideration of recovery efficiency, the proposed method can be used to design a horizontal extraction gas collection system and a cover system in better working condition, and to evaluate the maximum gas pressure below cover. These applications are illustrated by a worked example.

Wood is highly regarded as the most sustainable resource that is widely used in structural applications. To extend its practicality in electrically conductive applications, it is necessary to confer electrical conductivity to the insulating wood. The most common strategy is to derive carbonized wood powder via an annealing process. Even though these carbonized wood powders are electrically conductive, they lost the ancestry characteristic of wood, that is, excellent mechanical properties. As such, it is of great importance to realize the concept of conductive wood while at the same time maintaining or even enhancing its mechanical properties further. By leveraging on the naturally formed transportation channels found in trees, conductive particles can be aligned along these ordered channels. To substitute active transport in living plants, a vacuum pressure impregnation process was used to infiltrate these conductive particles into the transportation channels. As a result, Cu/wood composite, denoted as Cu-SW, exhibited a minimum volume resistivity of 1.366 × 10

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...

A process to upgrade a biogas product to biomethane has been investigated. Recycling of an absorbent is important for low-cost upgrading of biogas by chemical absorption. This study investigated the alkaline recovery of absorbent solution by thermal decomposition at various temperatures (75, 85 and 95 °C) and various vacuum levels (0.2, 0.4 and 0.6 bar). During heating, CO2 and H2S were released from the absorbent solution, which increased the pH. The highest pH 10.58 was reached for NaHCO3 solution from initial pH 8.86 when treated at 95 °C and 0.6 bar vacuum level (gauge pressure). The mass fraction of CO32− in the solution increased from 0.06 to 0.78. Experiments on H2S removal from NaHS solution gave the highest pH 10.38 at 95 °C and 0.6 bar vacuum pressure. Moreover, the performance of the recovered alkaline solution was tested in biogas absorption. The results show that CO2 and H2S removal efficiencies of alkaline solution before and after recovery were similar, at 80 and 99 % respectively. This study demonstrated that thermal decomposition has high potential for recovering the alkaline used absorbent, for recirculation back into the absorption process.

A central solenoid model coil (CSMC) is to verify the large-scalar superconducting coil manufacture technology for China Fusion Engineering Test Reactor (CFETR) in Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). The CSMC composed of Nb3Sn and NbTi hybrid superconducting magnet can reach to 12 T maximum magnetic field. The main manufacturing processes of the coil are developed and verified by R&Ds and mockup coil fabrication. For now, all the five coils winding and 2/3 of terminals fabricating are finished, and the heat treatment for the Nb3Sn inner coil is completed. The turn releasing and insulation wrapping process and station for the heat treated Nb3Sn coil has been developed. The major remaining processes for the five coils are ground insulation wrapping and vacuum pressure impregnation (VPI). The mockup coil VPI will be performed firstly to validate the process. This article introduces the main manufacturing progress of the CFETR CSMC.

Conventional landslide drainage methods always seem to lack a long-term and efficient drainage capacity. Thus, it is necessary to develop a new drainage method that does not have these disadvantage...

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.

The performance of vertical pumping wells in municipal solid waste (MSW) landfills can be effectively enhanced if vacuum pressure is applied to the well. In this study, a dual-porosity model for coupled leachate and gas flow to vertical wells in MSW landfills has been established. The proposed model divides waste into fracture and matrix domains; the leachate and gas in these two domains flow horizontally and vertically into a vertical well together, and mass exchange occurs between them. The hydraulic conductivity of the fracture domain is much higher than that of the matrix domain. The model is solved using the finite-difference method to obtain numerical solutions of the leachate pumping rate Qw and leachate level drawdown S. Numerical simulations indicate that Qw and S decrease with the increasing hydraulic conductivity ratio of the fracture and matrix domains, kirf/kirm. As the proportion of the fracture domain in the total domain wf increases, additional large pores are available for leachate flow, and Qw and S gradually increase. Qw and S estimated by the single-porosity model are 1·5–3·0 times as large as those obtained using the dual-porosity model. Qw and S increase with the increasing vacuum pressure applied at the pumping well. A field vacuum well pumping test was carried out at Tianziling landfill to verify the proposed model. When the vacuum pressure at the well increased from 0 kPa to −30 kPa, Qw increased from 33 m3/day to 45 m3/day at t = 36 h and S increased from 2·7 m to 5·6 m at a radial distance from the pumping well r = 10 m. The dual-porosity model performed better than the single-porosity model when simulating the pumping test.

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 ...

Using the theory of oscillations of theoretical mechanics, a method has been developed for calculating the parameters of a selected massager cage. The resulting equations allow one to select the main operating parameters of the massager, to calculate their effective values.

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.

A series of modified triaxial tests was conducted to investigate the deformation characteristics of mini-prefabricated vertical drain (PVD) unit cells. The factors considered are the (1) magnitudes of surcharge load (ps) and vacuum pressure (pvac); (2) pre-vacuum consolidation period (tva) before applying surcharge load; (3) surcharge loading rate (SLR); and (4) initial effective stress state in the specimens. Based on the test results, relationships between the coefficient of earth pressure (Kes) at the end of surcharge load application and the normalized horizontal and vertical specimen strains are established. Further, a method is proposed for estimating the value of Kes, and therefore the horizontal and vertical strains of the PVD improved soil layer subjected to combined vacuum pressure and surcharge load using loading conditions and basic soil properties. Finally, the proposed method was applied to a case history reported in the literature and good agreement between the field-measured and calculated lateral displacement and settlement was obtained, which suggesting that the proposed method can be a useful tool for designing preloading projects involving combined vacuum and surcharge loads.

Annotation Purpose. Substantiation of design parameters of two-chamber collector of milking apparatus by stabilization of vacuum mode of milkline of milking apparatus. Methods. An analysis of the results of experimental studies was used, which were carried out in laboratory conditions using methods of planning multi-factor experiments and statistical processing of experimental data using appropriate software. Results. Based on the results of theoretical substantiation, a prototype of a two-chamber milking collector of a milking machine was made and experimental studies were carried out on with varying structural factors according to the intensity of milk breeding. The analysis of the results of the experimental studies indicates that the rational diameter of the milk hose is 12 mm, with a throttle hole of 2 mm. The use of the proposed two-chamber collector with a portion inlet of air in the milking machine allows us to stabilize the vacuum pressure in the sucking phase, as a result of which milk with low content of somatic cells is of the highest quality. Conclusions. It has been found that the stable operation of the milking machine provides a constant vacuum pressure in the sucking phase and a sufficient drop in the vacuum pressure in the compression phase. The appropriate pressure level will be maintained by combining the diameters of the milk hose 12 mm and the throttle opening 2 mm. Keywords: milking machine, vacuum pressure, milk-shaped hose, throttle hole, two-chamber collector.

Composite scaffolds are made by various methods, such as copolymerization, freeze gelation, and thermally induced phase separation, which can compound materials with different properties using solvents and heat. However, it is difficult to compound solvents and heat-sensitive materials such as natural polymers. In this study, we investigated a vacuum pressure impregnation (VPI) method for creating a composite of natural polymers. A collagen solution could not be introduced into a poly (l-lactide) (PLA) porous material using an immersing treatment, but it is possible using the VPI method. The resulting PLA-collagen composite scaffold had greater water adsorption and degradation than a PLA scaffold. These results indicate that VPI may be a promising method for creating composites of natural materials. Impact Statement This is the development of a method for introducing cells into a completed porous material in a short time. This technology is expected to be applied to tissue regeneration and 3D culture.