PRO can be viewed as an intermediate process between FO and RO, where hydraulic pressure is applied in the opposite direction of the osmotic pressure gradient (similar to RO). Loeb and Norman  proposed pressure-retarded osmosis (PRO) process. In a PRO process, water flows naturally from a low salinity stream (feed water) at an ambient pressure across a semi-permeable membrane to a pressurized high salinity stream (draw solution) driven by the osmotic pressure difference across the membrane. Chou et al.  first time reported the fabrication of thin-film composite hollow fiber membranes which could be used in PRO process. Composite hollow fiber membrane was prepared by depositing a thin layer of PA on PES hollow fiber via IP. The main reagents used were m-phenylenediamine (MPD), trimesoyl chloride (TMC) and cyclohexane. From the performance test, it was revealed that The TFC PRO hollow fiber membranes have a water permeability (A) of 9.22 × 10 −12 m/(s Pa), salt permeability (B) of 3.86 × 10 −8 m/s and structural
Thinfilmnanocomposite (TFN) membranes containing 0.05 or 0.10 w/v% functionalized titanate nanotubes (TNTs) in polyamide selective layer were prepared via interfacial polymerization of piperazine (PIP) and trimesoyl chloride (TMC) monomers. Nanomaterials were dispersed into the monomer solution using two different approaches. In the first one, the functionalized TNTs were dispersed into the amine aqueous solution, while in the second approach the same nanomaterials were dispersed in TMC organic solution. The TFN membranes were characterized and compared with a control thinfilm composite (TFC) membrane to investigate the effect of nanofiller loadings and the fabrication approach on membrane properties. Results showed that introducing nanofillers into the organic phase was more effective to synthesize a TFN membrane of greater separation performance as the use of rubber roller to remove aqueous solution from the substrate surface could cause the loss of a significant amount of nanofillers, which further affected the polyamide layer integrity. It was also found that incorporation of high nanofiller loading tended to interfere with interfacial polymerization and weaken the bonds between monomers blocks, resulting in poor polyamide-nanotubes integrity. Compared to the TFC membrane, the TFN membrane made of 2% PIP and 0.15% TMC with 0.5% nanofiller incorporation could achieve greater water flux (7.5 vs 5.4 L/m 2 .h.bar) and Na
First o f all, I would like to thank almighty Allah for establishing me with strength and faith, and giving me the sight to realize myself. Incontrovertibly, 1 owe my supervisor, Professor Dr. Ahmad Fauzi Ismail a great deal o f debt, for his kindness and guidance throughout my entire research. He encouraged me by his constructive advices and intellectual supports during my doctoral period. His friendly personality has always created a positive atmosphere and motivated me to work. My sincere appreciation also extends to my co-supervisor Dr. Lau Woei Jye who has been the most energetic and great inspiration to me in my research and gave me the inspiration to keep on the right direction during my research. Without him, 1 could never accomplish my study smoothly. It is with immense gratitude that I acknowledge Professor Dr. Takeshi Matsuura for his fundamental and invaluable direction, guidance and assistance. I have learned from him not only how to perform and interpret experiments but also how to think and move the project forward. His exceptional insights into engineering have immensely helped me to enrich my knowledge. In addition, I want to extend my thanks to the all Advanced Membrane Technology Research Centre (AMTEC) members for their friendship, invaluable assistance and giving me invaluable advice during throughout this period.
2.2.4. Incorporation of inorganic ﬁ llers into polyamide membrane In recent years, nanotechnology opens new frontier in the devel- opment of advanced materials with improved properties for SWRO desalination. Fig. 8 illustrates the incorporation of zeolite and carbon nanotubes (CNTs) within the PA matrix [92,93]. These novel approaches have attracted considerable interest among membrane scientists to produce a new class of thin- ﬁ lm nanocomposite (TFN) membranes with desired functionalities and properties. Early study showed that TFN membranes composed of zeolite A (LTA) exhibited a dramatic improvement in both permeability and fouling resistance . It has been reported that zeolite nanoparticles offer preferential ﬂ ow paths for water molecules, leading to greater water productivity . Since the size of zeolite nanoparticle is tunable, it could there- fore create a “ percolation threshold ” through the PA matrix which in turn improved membrane water permeability without sacri ﬁ cing salt rejection rate [61,94]. At very low zeolite loading used, produced TFN membranes were found to demonstrate excellent water perme- ability (37 – 42 L/m 2 h) with slightly improvement in salt rejection (95.7 – 99.5%) as compared to the neat commercial TFC membrane (~33 L/m 2 h and 99.3%) when tested using 32,000 ppm NaCl solution
impact of nanomaterials addition on the dope solution viscos- ity and PSF substrate properties with respect to surface con- tact angle (both top and bottom surface) and water permeability are summarized in Table 2. Overall, it was found that the viscosity of PSF dope solution increased upon addi- tion of nano-material. With respect to hydrophilicity, the nanomaterial-embedded PSF substrates exhibited lower water contact angle compared to the pristine PSF substrate. For the membrane top surface, the nanomaterial-embedded PSF sub- strates showed contact angle between 68.4 ° and 70.5 ° while pristine PSF substrate displayed 73.1 ° . Further analysis revealed that the bottom surface of nanomaterial-embedded PSF substrates also showed lower contact angle (62.8–66.7 ° ) in comparison to PSF substrate (69.2°). Comparing among three nanomaterial-embedded PSF substrates, it can be seen that Substrate TiO 2 and Substrate GO displayed very similar con-
The PES membrane was mounted via adhesive tape on the glass plate. Silicone rubber and a frame were attached on it to create space for stagnant solution. The PA active layer was formed by interfacial polymerization on top of the PES substrate. An average 20 mL of aqueous solution containing 2% w/v PIP (20 g PIP in 1000 mL distilled water) was poured on the membrane until all the membrane surface was covered. Later the PIP solution was removed out and was replaced with organic (n-hexane) solution containing 0.15 w/v % TMC (1.5 g TMC in 1000 mL n- hexane). The dipping time in both solutions was set at 45 s each. The interfacial polymerization reaction of PIP and TMC on PES membrane results in the formation of PA TFC membranes. The TFC membrane was then cured at 60 °C in the oven for 10 min. The membrane was thoroughly washed with warm water to remove unreacted amines. The GO/PES TFN membranes were fabricated as TFC membrane. 0.1 w/v% of GO were dispersed in the TMC solution and incorporated into the PA layer during the interfacial polymerization reaction.
With the help of nanotechnology, membrane science has introduced a novel gamut in science and technology. By using new nanoparticles and nanocomposites among the structure of membranes, the TFNs were born to help the separation and purification processes. In order to fabricate high efficiency thinfilm nanocomposites, many parameters namely increasing selectivity, permeability and porosity besides the reduction of fouling or improvement of salt rejection, need to be taken into account. In addition, many manners, theories and additive particles are also modified and chosen with regards to time and application. In conclusion and to the best of our knowledge, using TMC in fabrication of the base layer and the nanosilica in other parts are the most favorite particles so far.
modify transport properties of RO membranes by employing different types of molecular sieve nanoparticles in PA ﬁ lm [48,49]. Fig. 5 depicts the new concept of embedding molecular sieve nanoparticles in the top selective layer in the preparation of thin ﬁ lm nanocomposite (TFN) membrane. The new concept was ﬁ rst started by Hoek et al.  in early 2007. In their pioneering work, it is experienced that the super-hydrophilic and negatively charged zeolite-A embedded throughout PA thin ﬁ lm was able to dramatically improve the permeability of the TFN membrane and remained equivalent salt rejection when compared with the pure PA composite membrane. Since the size of the zeolite particles is designed to match the PA ﬁ lm thickness, it thus provides a favorable ﬂ ow path through each particle incorporated into membrane, leading to high water permeation . This improved membrane water process is just as effective as current technology but more energy ef ﬁ cient and potentially less expensive. In order to further enhance water molecules transport rate, Fathizadeh et al.  in year 2011 impregnated bigger pore size of zeolite NaX (7.4 Å) in the thin ﬁ lm layer with the aims of creating larger molecular tunnels for water to ﬂ ow. It is found that this particular pore size of zeolite offers preferential ﬂ ow paths for water molecules of 2.7 Å in diameter but restricts the permeation of hydrated sodium and chloride ions (8 – 9 Å). Instead of differences in particles' size, controllable design in interfacial chemistry of mem- brane is also possible using other type of molecular sieves, owing to their tunable functionality with respect to hydrophilicity, charge density and antimicrobial capability. It was recently reported by Kim and Deng  that hydrophilized ordered mesoporous carbons (H-OMCs) modi ﬁ ed from pristine OMCs were possible to be used as nano- ﬁ ller in making thin- ﬁ lm polymer matrix of improved proper- ties. According to them, the plasma treated H-OCMs could be well dispersed in the aqueous solution which were likely to minimize large
The Application of thin-films and shallow flows are very common in nature and technology so an understanding of their mechanics is very important in many real life problems. In this present study we are interested to deal with shallow flow to determine the bottom stress under the influence of periodic wind stress over the flow domain. The present work is of fundamental importance given the significant quantitative role that bottom stress plays to cause erosion and resuspension in a shallow mine tailings pond. Therefore, prediction of the bottom stresses in a shallow mine tailings pond is studied in this study. In general, surface tension has been neglected in most of the studies of shallow water flow. This can be quite reasonably justified, since in most practical applications of shallow flow, surface tension is relatively small. However, there may be still some applications in which surface tension plays a significant role. That is why the problem is formulated with and without the effect of surface tension to see the effect of surface tension on the flow field.
Figure 2 shows a relationship between P and vertical distance from the bottom, H. P was irregularly changed with vertical distance from the bottom. The thin Au ﬁlm was placed at the position of 90 mm from the bottom where it received the maximum incident ﬂux of microwave. Micro- wave irradiation was conducted at 1 kW for 600 s in air. As shown in Fig. 2, net incident ﬂux of microwave was 563 W. The temperature of thin Au ﬁlm was measured using a glass ﬁber type of radiation pyrometer (Chino Co. Ltd., IR-FL3). Microwave cavity was shielded to prevent the entrance of light. The surface morphology of thin Au ﬁlm was observed using an atomic force microscopy (AFM, Digital Instruments Co. Ltd., Nano Scope III). The thickness of thin Au ﬁlm was measured using AFM (scratch method). Structural analysis was performed with X-ray diﬀraction (XRD, Rigaku Co. Ltd., CN4037A1). The resistivity of thin Au ﬁlm was measured using four-point probe technique at room temperature.
Zinc sulphide thinfilm was deposited on microscope glass slide substrates. The substrate was cleaned prior to deposition process. It was kept overnight in chromic acid. The chromic acid solution was prepared by adding 70 gm. K 2 Cr 2 O 7 in 320 cc distil water. Finally 120 cc sulphuric acid (99% H 2 SO 4 ) was added to the mixture for complete dissolution of K 2 Cr 2 O 7 . This was followed by rinsing the substrate in distilled water and ultrasonic cleaning in equivolume mixture of acetone and alcohol in an ultrasonic cleaner. The substrate was tightly held in a holder so that only a requisite area for film deposition was exposed. The film thickness was measured gravimetrically 6 by weighing the
able with either an n-type or a p-type impurity to reach resistivity as low as 0.1 ohm-cm [2,3]. Diamond has a wide band gap energy level of 5.45 eV and it is chemically inert and biocompatible. These unique combination of diamond properties allows its use in a wide range of industrial applications. The superior quality of diamond among other materials is well known in optical, mechanical, thermal and electronic applications [4-6]. For several optical applications there is a need for a reflective optical surface, there is also need for diamond as stronger mechanical material for voltage converter, circuit breaker and other microsystems [4-7]. These microsystems with diamond as thinfilm can benefit from the versatile properties of the diamond. The diamond film deposited by microwave plasma enhanced chemical vapor deposition (MPCVD) can be manipulated during nucleation and growth conditions to achieve specific characteristics. It is meaningless determining an absolute quality for a diamond film without defining the ultimate application. For instance, optical windows require high transparency in the range of wavelength considered [8-10]. The transparency is linked to the diamond’s intrinsic quality (lowest amount of structural defects and impurities), as well as to roughness. The use of polycrystalline diamond film as a heat spreader also requires high intrinsic quality and a limited grain boundary network. However, mechanical applications do not need a very high crystallographic quality, but instead a high deformation resistance and sometimes a very
Figure 3 shows SEM images of cobalt oxide thinfilm an- nealed at 400˚C - 700˚C. Figure shows the nearly same surface morphology for all films with slight increase in grain size .The film surface looks smooth and composed of very fine elongated particles smaller than 80 nm in length connected by two-three spherical grains of about 40 nm - 45 nm in diameters. From SEM image, overgrowth of clus- ters is clearly seen. Initially grown nanograins may have increased their size by further deposition and come closer to each other. The cobalt oxide film surface is well cov- ered without any pinholes and cracks. Such surface mor- phology may offer increased surface area, feasible for super capacitor and gas sensing application .
Fluctuating irradiance, spectral, and temperature characteristics causes a wide sweep in the outdoor performance of thin-film photovoltaics (TFPVs). In order to forecast the outdoor behavior of such TFPV modules it is customary to develop empirical models augmented from measured datasheets, which in-turn leads to key performance insights of these modules. The impending discourse is dictated by this motive at the first place, followed by an analysis of real-time results comprising of data procured from various locations by dint of standard approaches. Analysis of spectral behavior based on measured and simulated spectra are also discussed in this context.
Metal-induced crystallization (MIC) is a metal-induced transformation of amorphous silicon into crystalline silicon. Silicide, or Si-metal alloys are common materials in VLSI circuits. It is well known that the interactions between some metals, such as Al and Au, and amorphous silicon induce the crystallization of amorphous silicon at temperatures much lower than those of SPC processes. Though the kinetics of such a low temperature crystallization process has not been established, most of the experimental data show that addition of a small amount of metal impurities can dramatically enhance the crystallization of amorphous silicon at low temperatures. The reaction between a metal and amorphous silicon occurs at the interface and it lowers the crystallization temperature. Metal used as contact layers in metal/a-Si structures can be classified into two groups: silicide forming metals (Ni , Co, Cr, Pd , and Pt) and elemental metals that do not form silicides (Al , Ag, Au , and Sb). Thin-film transistors made of pc-Si crystallized via MIC processes show electron mobility of 121 cm 2 /Vs .
for the development of thin coatings of oxides. Firstly, coating of the complex shapes became significantly easier utilizing the dipping which is thought to be the major drawback of the coatings via vapour deposition. Secondly, very small quantities of precursor are required and making the process economic, thus, the price of metal organic raw material is not of much significance. Regardless of large shrinkages in the drying process, thin oxide coatings actually do not fracture when the surface arrangements are fine, as rather than shrinking laterally the gel film would shrink in the width direction
Planar waveguides are usually thin-films of an optically dense medium on a suitable substrate of an optically rarer medium and can be fabricated by a wide variety of methods (ion-exchange , spin  and dip coating  from solution, chemical vapour deposition , sputtering , etc.). The choice o f a suitable fabrication method for biosensor use will most likely be determined by cost. Planar guides, as with optical fibres, exhibit a high evanescent field strength and low penetration depth, but their planar geometry, greater surface area and more compact size and shape makes them more amenable as disposable immunosensor devices. A further advantage of planar waveguides is the possibility of surface patterning of the waveguide which would allow reference/calibration and multiple analyte measurements to be made on one device together with any optical signal processing that may be necessary [42, 50]. Cost of fabrication will limit the extent to which such ideas can be incorporated and thus, it is essential that cheap thin-film fabrication techniques are employed using materials that can be easily processed (ie. etching, photolithography, etc.).
In the present investigation, an effort was made to disperse multi-walled carbon nanotubes (MWCNTs) via ultrasonic processing in PVDF matrix to form 0 - 3 nanocomposite. The dielectric and pyroelectric properties of the resultant composite films were measured. After using forgoing parameters, to assess their use as pyro- electric infrared detectors, and as vidicons, various Fig- ures-of-merit have been calculated and compared with pristine PVDF film.
that only the original (and very expensive) photo-definable polyimide would withstand the required processing steps, produce a suitably smooth surface finish and promote metal film adhesion. We are now using another layer of HD-4000 spin-on polyimide to serve as a base leveling layer which the sensor array is to be fabricated upon. This is a self-leveling layer which will offer a smoother surface (similar to the original Kapton® patches). An additional benefit of the spin-on polyimide is that it was specifically designed to promote adhesion of deposited metal films. Figure 37 shows an image of th single-layer Cirexx® patch, with our spin-on polyimide (HD Microsystems HD-4000) base layer.
and the generation of secondary pollutants. On the other hand, membrane processes are considered a suitable alternative for oily wastewater treatment (Ong, Lau, Goh, Ng and Ismail, 2014). Membranes based on poly(vinylidene fluoride), PVDF, and its copolymers are of high interest for wastewater treatment, due to its outstanding properties, like mechanical and chemical resistance and hydrolytic and thermal stability (Salazar, Nunes-Pereira, Correia, Cardoso, Gonçalves, Martins, Ferdov, Martins, Botelho and Lanceros-Méndez, 2016). Membranes based on PVDF have been investigated for the removal of different pollutants from water, such as copper ions (Zhang, Wang, Liu, Xu, Han and Xu, 2014), natural organic matter (Song, Shao, Wang and Zhong, 2014), proteins (Zhang, Zhang, Cheng, Xu, Xu, Chen, Lai and Tung, 2012), volatile organic compounds (Ramaiah, Satyasri, Sridhar and Krishnaiah, 2013) and desalination (Zuo, Shi, Tian, Yu, Wang and He, 2013), among others. From all the PVDF copolymers, poly (vinylidene fluoride-trifluoroethylene) presents suitable physicochemical properties for photocatalytic applications, like a high UV resistance. Furthermore, it allows the production of membranes with controlled porosity and pore size, possesses good chemical, thermal and mechanical resistance (Aoudjit, Martins, Madjene, Petrovykh and Lanceros- Mendez, 2018). Also, this copolymer has shown remarkable photocatalytic activity in degradation of organic compounds such as methylene blue (Martins, Gomez, Lopes, Tavares, Botelho, Irusta and Lanceros-Mendez, 2014) and tartrazine (Aoudjit, Martins, Madjene, Petrovykh and Lanceros- Mendez, 2018).