The paper presents two methods that are aimed at detecting fouling in cross-flow heat exchangers under normal operating conditions, using measurements that can easily be obtained, i.e. inlet and outlet temperatures and the mass flows of the hot and cold fluids. The methods are a) a physical method that is based on number of transfer units (NTU) relations and b) a black box model that is estimat...

removing of ions from different water and waste water is one of the most important of nanofiltration potential for different aims, such as softening of potable water, remove of heavy metal ions and purification of waste water to reuse. in this study nanofiltration was used to remove of the most important ions (na+, k+, ca2+, mg2+, so42-, cl-) in sugar beet press water to reuse of this stream. e...

fouling is one of the main parameters in design of any exchanger. ignoring this parameter causes problems such as overheating or under- heating of process streams. in this article a heat exchanger network was designed using process streams data in cdu of tehran refinery. then using tema fouling factors, network exchangers were designed and area and cost were estimated. by changing fouling facto...

As a reaction to the increasing noise pollution, caused by the expansion of airports close to residential areas, porous trailing edges are investigated to reduce the aeroacoustic noise produced by flow around the airframe. Besides mechanical and acoustical investigations of porous materials, the fouling behavior of promising materials is an important aspect to estimate the performance in long-t...

Advanced wastewater treatment using membranes are popular environmental system processes since they allow reuse and recycling. However, fouling is a key limiting factor and so proprietary systems such as Avanti's RPU-185 Flexidisks membrane bioreactor (MBR) use novel rotating membranes to assist in ameliorating it. In earlier research, this rotating process was studied by creating a simulation ...

We investigated seasonal variation in membrane fouling in membrane bioreactors (MBRs) treating municipal wastewater regarding the difference between physically reversible and irreversible fouling. Two separate MBRs with different solid retention times (SRTs) operated in parallel for about 200 days including high- and low-temperature periods to evaluate the effect of operating conditions on seas...

One of the most costly problems in the maintenance of heat exchangers is de-fouling, which results in a waste of time and money. The present study includes two parts: the first section addresses fouling factor, its disadvantages, and circumstance of formation, fouling types, and general models of the fouling. In the second part, the problem of fouling in oil exchanger and particular type of fou...

1. introduction the earth's crust is composed of various landforms. these forms are constantly changing. in this change, both of internal and external factors have a decisive role. the internal factors led to the formation of the primary structure and external factors that cause erosion, deformation and destruction of these forms. areas that have been affected by these activities confronted by ...

The Isère River system drains parts of the Western Alps in south-eastern France. Zircon fission-track data of the Isère River and its tributaries show a range of apparent cooling ages from about 7 to 150 Ma. Zircons with Jurassic to early Tertiary cooling ages are derived from partially reset or non-reset sedimentary cover units of the internal and external Alps, while grains belonging to the m...