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The main challenges are [2]: - Membrane fouling: further understanding the mechanisms of membrane fouling and development of more effective and easier methods to control and minimize membrane fouling; - Pretreatment: effective methods to limit membrane clogging and operational failures; - Membrane lifespan: increasing membrane mechanical and chemical stability; - Cost: reducing costs for maintenance and replacement of membranes, energy requirement and labor requirements; - Plant capacity: scaling up for large plants.
Membrane fouling reduces long term flux stability and implies membrane cleaning, which increases the overall cost, or may even require membrane replacement in the cases where cleaning fails to recover the adequate flux properties [4].
There are many factors affecting membrane fouling, such as membrane and module operating conditions [5], and biomass characteristics (including suspended solids and extra-cellular polymeric substances, EPS's).
Both nutrient supply and available contact time affect bacterial growth rate; these two parameters are inter-related.

Introduction Due to the differences in the external environment such as temperature, humidity, ultraviolet radiation, acid rain and other factors, both corrosion and aging have an impact on aircraft in service.
What’s more, surface treatment and coating defects, extra material blocking in the drainage hole may lead to localized corrosion, which will affect the organizational structure of the material properties and initiate fatigue crack.
Indeed aeronautical structures, such as wings or fuselage riveted lap- joints, undergo strong mechanical constraints.
Signal of near-surface defect returns earlier than the deep defect, so the near-surface defect affects the early stage of the sensor signal and deeply buried defect affects the latter part of the sensor signal.

The excellent mechanical properties including better creep and oxidation resistance are controlled by the grain size and secondary dendritic arm spacing of primary phase, as well as the morphology and distribution of γ′ phase inside the γ matrix [2-4].
From a theoretical interest and technological importance, it is essential to understand the microstructure characteristics and the underlying formation regularities to obtain the desired properties to the material [5-7].
Thus, a subsequent aging treatment is required to optimize the mechanical properties of rapid solidified ingots.
Due to the nucleation and growth factors controlling the whole precipitation process are changed significantly by the foregoing non-equilibrium transformation, the precipitation behavior of rapid-quenched sample is much different to the conventional fabrication routes [18-20].
The precipitation behavior of γ′ phase in the dendritic core is also affected by the cooling rate, as verified by the FE-SEM pictures shown in Fig. 2.

Venkatesh3, e 1Faculty of Mechanical Engineering, Universiti Malaysia Pahang, 26600, Pekan, Pahang, Malaysia. 2Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100, Durian Tunggal, Melaka, Malaysia. 3aculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai , Johor Malaysia.
Introduction Titanium and its alloys are considered difficult-to-machine materials due to several factors such as very high temperature imposed on the cutting edge during machining, being high strength at elevated temperature and strong adhesion to many cutting tools.
Some of the methods were using special oil on the cutting tool, modifying titanium properties, and introducing new tool materials.
The primary issue with cryogenic cooling is change of material properties with abruptly-reduced temperature, which adversely affects tool wear and surface finish.
Properties of various materials including titanium alloy at liquid nitrogen temperature were reported.

Similar to the mechanical properties, their dissolution rate is also depending on the composition.
This natural mineralization has been adopted to produce ceramics and/or coatings with unique mechanical properties [60].
During film deposition, the structure of the film forms rapidly (as compared to bulk structures) and is influenced by several complex factors.
Bioactive glass ceramics: Properties and applications.
Bioactive metals: Preparation and properties.

Furthermore, the particle's size, the material composition, and the structure of the particle are important factors in passing the BBB.
Moreover, it has controllable mechanical properties and degradation rates.
Another interesting property is that apparently P-gp (P-glycoprotein) efflux transporters are not affecting them.
Since the properties of the polymer and the diffusion coefficient affect drug release, a controlled drug release can easily be attained.
ALEXIS F., PRIDGEN E., MOLMAR L.K., FAROKHZAD O.C., "Factors affecting the clearance and biodistribution of polymeric nanoparticles", Molecular Pharmaceutics 5, 4 (2008), p. 505-515 2.

Wear damage is widely found in mechanical components, however it is difficult to eliminate it since there are many different types and mechanisms of wear.
A lot of factors affect it, e.g. mechanical force and displacement, materials, existence and the properties of lubricants, environments etc.
Another feature of wear damage is that it usually evolves very slowly when compared with other mechanical failures.
But it may be extended to further general wearing components because it deals with simple mechanical variables, a force and displacement.
Running-in period, the alteration of wear mechanisms and environmental effect can affect the behaviour of the depth increase.

Microstructure of the duplex steels combines the mechanical properties of both phases - high strength, high ductility, and high work-hardening rate - with a very good corrosion resistance.
The small grain size contributes to the good mechanical properties.
Cyclic mechanical properties depend strongly on the plastic strain amplitude and on the nitrogen content [5].
The chemical composition is shown in Table 1; the main mechanical properties are shown in Table 2.
The growth of a crack is only slightly affected by the crack coalescence.

Kahraman et al [6] stated that the performance of a bit requires information from variety of sources which includes formation properties, operating condition and bit design analysis.
However, the major parameters affecting bit performance are the physico- mechanical properties of the rock.
The objectives of this work therefore, are to determine rock properties affecting ease of drilling, characterize the limestone formation and compare the performance of the different tri-cone bits employed.
Feridunoglu,: Dominant Rock Properties Affecting Penetration Rate of Percussive Drills, International Journal of Rock Mechanics and Mining Science, Vol 40 No. 2, (2003), pp 711 -723 [7] A.
Miller: Engineering Classification and Index Properties for Intact Rock, University of Illinois, U.S.

Sujan1, d 1 Mechanical Engineering Department Curtin University Sarawak, CDT 250, 98009, Miri, Malaysia 2Deep Water Research Cluster, Universiti Teknologi PETRONAS, Seri Iskandar, Malaysia  3Department of Mechanical Engineering, Faculty of Science, Technology, Engineering & Mathematics (FOSTEM), INTI International University, Persiaran Perdana BBN, Putra Nilai, 71800 Nilai, Negeri Sembilan, Malaysia amesfingizaw@curtin.edu.my, b tamiru.lemma@petronas.com.my, cabdulwehabadem.ibrahim@newinti.edu.my, dD.sujan@curtin.edu.my Keywords: Heat Recovery, Steam Generator, Modeling, Simulation Abstract.
As highlighted by Ong'iro, Ugursal, et al. [9], development of a suitable model is affected by many factors.
However, regardless of the situation therein, accurate model need to be used as the HRSG works in synchronous with the gas turbine hence affecting accuracy of the prediction on the overall performance.
All the required empirical equations for the calculation of properties of air, exhaust gas, and steam are taken from literature [11] and standard gas tables [12].
Pinch and Approach Temperatures: Performance of the HRSG is affected by pinch point temperature, approach temperature, and pressure drop.