scholarly journals Microfiltration Membranes Modified with Silver Oxide by Plasma Treatment

Membranes ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 133
Author(s):  
Joanna Kacprzyńska-Gołacka ◽  
Anna Kowalik-Klimczak ◽  
Ewa Woskowicz ◽  
Piotr Wieciński ◽  
Monika Łożyńska ◽  
...  

Microfiltration (MF) membranes have been widely used for the separation and concentration of various components in food processing, biotechnology and wastewater treatment. The deposition of components from the feed solution and accumulation of bacteria on the surface and in the membrane matrix greatly reduce the effectiveness of MF. This is due to a decrease in the separation efficiency of the membrane, which contributes to a significant increase in operating costs and the cost of exploitative parts. In recent years, significant interest has arisen in the field of membrane modifications to make their surfaces resistant to the deposition of components from the feed solution and the accumulation of bacteria. The aim of this work was to develop appropriate process parameters for the plasma surface deposition of silver oxide (AgO) on MF polyamide membranes, which enables the fabrication of filtration materials with high permeability and antibacterial properties.

2019 ◽  
Vol 290 ◽  
pp. 02007
Author(s):  
Radu Dan Paltan ◽  
Cristina Biriş ◽  
Loredana Anne-Marie Rădulescu

Of many techniques that are used to optimize production and costs, the studies conducted within a profile company lead to our choice for testing the 6Sigma method (the most used method in the automotive industry) in view of the economic efficiency applied in the wood Industry company. This method measures how many flaws exist in a process and determines in a systematic way how to improve it by technical overhauling and eliminating or minimizing the process for efficiency. This research article aims to study the state of research on the optimization of the production process through technical overhauling for panels reconstituted from solid wood and ways to make production more efficient by cutting costs through technical overhauling. From preliminary research, we estimate that all the items founded and others that will result from further research will result in a significant decrease in production costs that are reflected in the cost of the finished product and consequently in increasing the yield of the company by maximizing its profit. At the same time it may be the basis of future research studies in the field. The easier it is to maximize profits, the lower the operating costs are and the higher recovery rate of investments are, that will result a change in the operating mode: “working smarter not harder”.


Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 411
Author(s):  
Irena Zizovic ◽  
Marcin Tyrka ◽  
Konrad Matyja ◽  
Ivana Moric ◽  
Lidija Senerovic ◽  
...  

This study investigates the modification of commercial cellulose acetate microfiltration membranes by supercritical solvent impregnation with thymol to provide them with antibacterial properties. The impregnation process was conducted in a batch mode, and the effect of pressure and processing time on thymol loading was followed. The impact of the modification on the membrane’s microstructure was analyzed using scanning electron and ion-beam microscopy, and membranes’ functionality was tested in a cross-flow filtration system. The antibiofilm properties of the obtained materials were studied against Staphyloccocus aureus and Pseudomonas aeruginosa, while membranes’ blocking in contact with bacteria was examined for S. aureus and Escherichia coli. The results revealed a fast impregnation process with high thymol loadings achievable after just 0.5 h at 15 MPa and 20 MPa. The presence of 20% of thymol provided strong antibiofilm properties against the tested strains without affecting the membrane’s functionality. The study showed that these strong antibacterial properties could be implemented to the commercial membranes’ defined polymeric structure in a short and environmentally friendly process.


1998 ◽  
Vol 30 (9) ◽  
pp. 1585-1602 ◽  
Author(s):  
D M W N Hitchens ◽  
J E Birnie ◽  
A McGowan ◽  
U Triebswetter ◽  
A Cottica

The authors use a method of matched-plant comparisons between food processing firms in Germany, Italy, Northern Ireland, and the Republic of Ireland to investigate the relationship between environmental regulation and company competitiveness across the European Union. Comparative competitiveness was indicated by measures of value-added per employee, physical productivity, export share, and employment growth. The cost of water supply (public or well), effluent treatment (in-plant treatment and/or sewerage system), and disposal of sludge and packaging were also compared. Total environmental costs in Germany, Italy, and Ireland were small: usually less than 1% of turnover. Compared with the Irish firms, German companies had relatively high environmental costs as well as productivity levels. There was, however, a lack of a clear relationship between company competitiveness and the size of regulation costs: in Ireland and Italy environmental costs were similar but German firms had much higher productivity; compared with German counterparts, Italian firms had lower environmental costs but higher productivity.


Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 709
Author(s):  
Asmat Ullah ◽  
Kamran Alam ◽  
Saad Ullah Khan ◽  
Victor M. Starov

A new method is proposed to increase the rejection in microfiltration by applying membrane oscillation, using a new type of microfiltration membrane with slotted pores. The oscillations applied to the membrane surface result in reduced membrane fouling and increased separation efficiency. An exact mathematical solution of the flow in the surrounding solution outside the oscillating membrane is developed. The oscillation results in the appearance of a lift velocity, which moves oil particles away from the membrane. The latter results in both reduced membrane fouling and increased oil droplet rejection. This developed model was supported by the experimental results for oil water separation in the produced water treatment. It was proven that the oil droplet concentration was reduced notably in the permeate, due to the membrane oscillation, and that the applied shear rate caused by the membrane oscillation also reduced pore blockage. A four-times lower oil concentration was recorded in the permeate when the membrane vibration frequency was 25 Hz, compared to without membrane vibration. Newly generated microfiltration membranes with slotted pores were used in the experiments.


2020 ◽  
Vol 21 (3) ◽  
pp. 51-55
Author(s):  
Mohannad A. Raheem ◽  
Raghad F. Qassim

   This research presents a comparison of performance between recycled single stage and double stage hydrocyclones in separating water from water/kerosene emulsion. The comparison included several factors such as: inlet flow rate (3,5,7,9, and 11 L/min), water feed concentration (5% and 15% by volume), and split ratio (0.1 and 0.9). The comparison extended to include the recycle operation; once and twice recycles. The results showed that increasing flow rate as well as the split ratio enhancing the separation efficiency for the two modes of operation. On the contrary, reducing the feed concentration gave high efficiencies for the modes. The operation with two cycles was more efficient than one cycle. The maximum obtained efficiencies were 97% and 97.5% at 5% concentration, 11 L/min, and 0.9 split ratio for twice recycled single stage and double stage hydrocyclones, respectively. The pressure drop was the same for the two modes of operation. It was concluded that using recycled single stage hydrocyclone was more economical since it reduced the cost of additional hydrocyclone.


2019 ◽  
Vol 52 (2) ◽  
pp. 191-212
Author(s):  
Christian Kalhoefer ◽  
Guenter Lang

Abstract Governments worldwide reacted swiftly to the global financial crisis by tougher regulations. This paper investigates the impacts of the regulatory environment on operating costs using panel data of 2,200 German banks over the timeframe from 1999 to 2014. We estimate cost functions with and without proxies for regulation and analyze the results with respect to period, bank size, and group affiliation. Our results show that regulatory costs were peaking in 2001, 2008, and lately since 2012. Most interesting, however, is the asymmetry of regulation: Whereas the cost effects were symmetric for all banks until 2003, the last ten years were different. Larger institutions and savings banks could neutralize the impacts of increasing regulation on operating costs. In contrast, smaller banks, especially if they are cooperative banks, were facing significant cost increases. We therefore expect unintended structural shifts like a reduction in the diversity of banks, which are negative for competition, service quality, and for the stability of the financial system. Zusammenfassung Weltweit wurde als Folge der globalen Finanzkrise die Regulierung des Finanzsektors verschärft. Dieser Beitrag geht der Frage nach, welche Konsequenzen diese Regulierungsmaßnahmen für die operativen Kosten im Bankengeschäft haben. Auf der Basis von Paneldaten von 2,200 in Deutschland aktiven Banken über den Zeitraum von 1999 bis 2014 schätzen wir Kostenfunktionen mit und ohne Proxies für Regulierung und werten die Ergebnisse nach Beobachtungsjahr, Bankengröße, und Gruppenzugehörigkeit aus. Unsere Ergebnisse zeigen Kostenspitzen in den Jahren 2001, 2008, und zuletzt seit 2012. Am interessantesten sind jedoch die asymmetrischen Effekte der Bankenregulierung: Während unsere Modelle bis einschließlich 2003 nahezu gleichmäßige Kostenbelastungen anzeigen, änderte sich dies deutlich mit dem Jahr 2004. Im Gegensatz zu großen Institute und Sparkassen, die die Regulierungskosten nahezu neutralisieren konnten, sahen sich kleine Institute und Genossenschaftsbanken mit deutlichen Kostensteigerungen konfrontiert. Als Folge dieser asymmetrischen Kostenwirkungen staatlicher Bankenregulierung erwarten wir unbeabsichtigte Strukturveränderungen wie z.B. Konzentrationsprozesse, die sich negativ auf Wettbewerb, Dienstleistungsqualität, und letztendlich auch negativ auf die Stabilität des gesamten Finanzsystems auswirken werden. JEL Classification: G21, G38


2011 ◽  
Vol 133 (07) ◽  
pp. 46-53
Author(s):  
Burton Dicht

This article analyzes the decisions and technological challenges that drove the Space Shuttle’s development. The goal of the Shuttle program was to create a reusable vehicle that could reduce the cost of delivering humans and large payloads into space. Although the Shuttle was a remarkable flying machine, it never lived up to the goals of an airline-style operation with low operating costs. In January 2004, a year after the Columbia accident, President George W. Bush unveiled the “Vision for U.S. Space Exploration” to guide the U.S. space effort for the next two decades. A major component of the new vision, driven by the recommendations of the Columbia Accident Investigation Board, was to retire the Space Shuttle fleet as soon as the International Space Station assembly was completed. With cancellation of the Constellation program in 2010, the planned successor to the Shuttle, the U.S. space program is now in an era of uncertainty.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Xinzuo Fang ◽  
Yufan Liu ◽  
Sheng Lei ◽  
Junfei Ou

Water pollution caused by oil leakage and oily wastewater has become a serious environmental problem. Therefore, it is important to develop an efficient material to remove oil from water. Given the cost and efficiency, the membrane with superhydrophobicity is the most used material for the separation of oil/water mixtures. However, many works have been done through modification with a fluorinated reagent, causing high cost and damage to the environment. In this work, a simple and fast two-step method is employed to achieve a superhydrophobic hair-like nanowire membrane. Through the alkali-assisted oxidation process and modification with nonfluorinated low surface energy chemical, the so-obtained membrane (denoted as SHM), with the water contact angle of about 164°, exhibits excellent separation efficiency for binary mixtures of water and oils (toluene, hexane, gasoline, and so on). Meantime, this membrane also exhibits excellent durability and reusability in the long-term separation process, indicating its great potential for practical application in the future.


Author(s):  
Bojun Wang ◽  
Aidan O’Sullivan ◽  
Lynnette Dray ◽  
Andreas W. Schäfer

Studies assessing the impact of market-based environmental policies in aviation rely on various scenarios of airline cost pass-through, because there is little empirical evidence with respect to the impacts of airline costs on airfares. Instead, the costs effect has been indirectly measured by proxy variables such as distance, fuel price, and aircraft sizes. This paper provides empirical evidence of airline cost pass-through by developing an airfare model that explicitly captures airline operating costs. Using a feasible generalized two-stage least squares (FG2SLS) approach, we obtained coefficients of airline fuel costs per passenger, non-fuel costs per passenger, and non-fuel costs per flight modeling for seven world regions (20 region-pair markets). A comparison of the estimated cost pass-through elasticities conducted across regional markets suggests that airlines may respond to the cost increases differently, depending on the cost types and the markets they operate in. Based on the estimated coefficients, we systematically evaluate the potential impacts of introducing a carbon tax policy within two major regional markets with distinct cost pass-through elasticities.


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