Transient Protection Optimization of Pipelines Using Air-chamber and Air-inlet Valves

S. Mahmood Jazayeri Moghaddas,Hossein M. V. Samani,Ali Haghighi 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.5

Air-chambers are mechanical devices capable of decreasing positive and increasing negative water-hammer pressures in pumping pipelines; however, large size air-chambers might increase the costs substantially. Also, air-inlet valves are powerful devices which can efficiently control negative pressures. Obtaining the best protection scheme where transient pressures are maintained in a safe bound while minimizing the protection cost is an optimization problem. In this research, a single objective optimization model is introduced in which the types and locations of air-inlet valves and the size of air-chamber are determined such that the total cost is minimized while all pressures along the pipeline are in the allowable range. Maximum and minimum transient pressures are considered as constraints in the optimization analysis using penalty functions. A self-adaptive real genetic algorithm is used to solve the problem. The model is applied to a real transmission pipeline with 4 m3/s flow capacity. The results indicate that the proposed model is capable to determine proper number of air-inlet valves, their locations and types so that the air-chamber size and the total cost are substantially reduced.

Use of Chemical Treatments to Reduce Tannins and Trypsin Inhibitor Contents in Salseed (Shorea robusta) Meal

Mahmood, S.,Khan, Ajmal M.,Sarwar, M.,Nisa, M.,Lee, W.S.,Kim, S.B.,Hur, T.Y.,Lee, H.J.,Kim, H.S. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.9

This study investigated the effect of chemical treatments on tannins (condensed and hydrolysable) and on the trypsin inhibitor (TI) activity in salseed meal. Triplicate samples of ground salseed meal (1 kg) were mixed with 820 ml of either distilled water (pH 5.3), 0.67 M acetic acid (pH 2.4), 0.67 M sodium bicarbonate (pH 8.2) or 2% polyvinyl-pyrrolidone (PVP) solution. The material was placed in airtight plastic containers and incubated at $37^{\circ}C$ for 0, 3, 6, 12, 24, 48 and 72 h. Samples of untreated salseed meal which had not been subjected to soaking or incubation were run through the analysis to serve as control. Addition of water, acetic acid, sodium bicarbonate and PVP solutions to salseed meal and subsequent anaerobic incubation at $37^{\circ}C$ significantly reduced chemically detectable tannins. At each incubation time, alkali solution was more effective than its counterparts. The effect of acidic solution on hydrolysable tannin was least among the treatments. All the treatments reduced TI activity of salseed meal. The reduction in TI activity by these treatments was similar and ranged between 80-84%. Treatment time effected a decrease in the contents of antinutritional substances. However, the effect of the treatment with the reagents, even for zero incubation time, was quite pronounced. It may be concluded from the present results that the treatment of salseed meal with sodium bicarbonate (0.67 M) is more effective in reducing hydrolysable and condensed tannin contents than PVP, water and acid solutions. Treatment with sodium bicarbonate solution is more economical and easier to handle than acid and PVP treatments. Incubation of the treated material for 12 h is reasonably effective, economical and safe from any mould growth.

Nonlinear Approach for Enhancement of Image Focus Volume in Shape From Focus

Mahmood, M. T.,Tae-Sun Choi IEEE 2012 IEEE TRANSACTIONS ON IMAGE PROCESSING - Vol.21 No.5

<P>Mostly, shape-from-focus algorithms use local averaging using a fixed rectangle window to enhance the initial focus volume. In this linear filtering, the window size affects the accuracy of the depth map. A small window is unable to suppress the noise properly, whereas a large window oversmoothes the object shape. Moreover, the use of any window size smoothes focus values uniformly. Consequently, an erroneous depth map is obtained. In this paper, we suggest the use of iterative 3-D anisotropic nonlinear diffusion filtering (ANDF) to enhance the image focus volume. In contrast to linear filtering, ANDF utilizes the local structure of the focus values to suppress the noise while preserving edges. The proposed scheme is tested using image sequences of synthetic and real objects, and results have demonstrated its effectiveness.</P>

Synthesis of Ag-Loaded TiO2 Electrospun Nanofibers for Photocatalytic Decolorization of Methylene Blue

M. Raffi,Zaira Batool,Mashkoor Ahmad,M. Zakria,Rana I. Shakoor,Muhammad Aslam Mirza,Arshad Mahmood 한국섬유공학회 2018 Fibers and polymers Vol.19 No.9

Titanium dioxide (TiO2) is one of the excellent photocatalysts used for degradation of environmetal pollutants. In this work, 2.5, 5.0 and 7.5 wt.% of silver (Ag)-loaded TiO2 nanofibers of mean size 52-134 nm were synthesized by electrospinning method. These electrospun nanofibers were calcined at 500 oC to enable the transformation of Rutile (R) phase to Anatase (A), elimination of reaction moieties from the TiO2 matrix and subsequently formation of Ag clusters. The effect of Ag loading on the morphology, crystal structure, phase transformation, and band gap of these electrospun nanofibers have been characterized by scannining electron microscopy (SEM), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), raman spectroscopy and UV-visible spectroscopy. These nanofibers exhibited a red-shift in the absorbance edge and a significant enhancement of light absorption in the wavelength range of 250-550 nm. These electrospun nanofibers were investigated for photodecomposition of methylene blue (MB), and photocatalytic decolorization rates were determined by pseudo-first-order equation. The rate constants for the pure and those of 2.5, 5.0, and 7.5 wt% Agloaded TiO2 nanofibers were computed to be 0.1439 min-1, 0.1608 min-1, 0.1876 min-1, and 0.2251 min-1 respectively.

Ground state opto-electronic and thermoelectric response of cubic XSnO3 (X = Ba, Sr) compounds

M. Bilal Saddique,Muhammad Rashid,Adnan Afzal,Shahid M. Ramay,Farooq Aziz,Asif Mahmood 한국물리학회 2017 Current Applied Physics Vol.17 No.8

The density functional has been implemented to deliberate the cubic perovskite XSnO3 (X ¼ Ba, Sr) for their elastic, electronic, optical as well as thermoelectric characteristic. The XSnO3 (X ¼ Ba, Sr) illustrates good pact of lattice parameter for these iso-structural compounds having cubic perovskite structure. The generalized gradient approximation based on the exchange-correlation functional is applied for computing structural and mechanical characteristic, whereas the electronic, optical and thermoelectric properties have been studied by the functional suggested by Tran and Blaha that is termed as of modified Becke-Johnson (mBJ) functional. The thermodynamics stability is recognized through the expression of enthalpies of formation, which is further verified from the calculated structural properties of cubic perovskite XSnO3 (X ¼ Ba, Sr). Moreover, various elastic parameters such has bulk modules B, Cij, shear modulus G, Young's modulus Y, anisotropy factor, B/G ratio and Poisson's ratio n have also been reported. It has been observed by band structure computation that the studied compounds exhibit an indirect band gap between the unoccupied Ba/Sr 6s/5s and the occupied O 2p orbitals. Detailed study of optical properties is presented under the incident photon energy upto 28 eV. Our computed static dielectric constant ε2(0) and refractive index n(0) are comparable with other theoretical and experimental values. Thermoelectric properties are presented in terms of computed Seebeck coefficient, electrical and thermal conductivities and their variation with the rise in temperature suggest that the studied compounds may find applications in the construction of various thermo-electric devices.

Performance of partial strength connection connected by thick plate between column flanges

Mahmood M. Tahir,Irwan Juki,Mohd Y. Ishak,Shahrin Mohammad,Abdullah Z. Awang,Roger Plank 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.2

Traditional beam connections to the minor axis of a column have relatively low strength and stiffness. A modified detail, using a plate welded between the toes of the column flange - referred to as a toe plate connection - is examined in this paper. The results of an experimental investigation for both flush and extended end-plate connections connected to a 25 mm thick end-plate are presented. The tests are complemented by finite element modelling which compares very well with the test observations. The results show a significant increase in both moment resistance and initial stiffness for this connection detail compared with connections made directly to the column web. This offers the prospect of more optimal solutions taking advantage of partial strength frame design for the minor axis as well as major axis.

On the origin of viscoelastic Taylor–Couette instability resulted from normal stress differences

Mahmood Norouzi,M.H. Sedaghat,M.M. Shahmardan,M.R.H. Nobari 한국유변학회 2015 Korea-Australia rheology journal Vol.27 No.1

In this paper, the effect of normal stress differences on the viscoelastic Taylor–Couette instability is studied numerically. The governing equations are discretized using FTCS finite difference method on a staggered mesh based on the artificial compressibility algorithm. Using the CEF model as the constitutive equation and the Carreau–Yasuda model as the viscometric functions, the flow between rotating cylinders has been studied for a range of radius ratios, Taylor numbers and rheological properties. It is shown that increasing the first normal stress difference destabilizes the flow field while increasing the negative second normal stress difference stabilizes the flow field. The main contribution of the current study is an answer to thisquestion: How do the first and second normal stress differences affect the stability of viscoelastic flowbetween rotating cylinders? For this reason, we used the order of magnitude technique to obtain a force balancerelation in the core region of flow. Based on this relation and numerical simulation, the origin of viscoelasticTaylor–Couette instability resulted from normal stress differences are studied in detail. Furthermore, a two dimensional analytical solution for the main flow velocity component between finiterotating cylinders is carried out considering the end effect of stationary walls

Optimal depth estimation by combining focus measures using genetic programming

Mahmood, M.T.,Majid, A.,Choi, T.S. North-Holland [etc ; Elsevier Science Ltd 2011 Information sciences Vol.181 No.7

Three-dimensional (3D) shape reconstruction is a fundamental problem in machine vision applications. Shape From Focus (SFF) is one of the passive optical methods for 3D shape recovery that uses degree of focus as a cue to estimate 3D shape. In this approach, usually a single focus measure operator is applied to measure the focus quality of each pixel in the image sequence. However, the applicability of a single focus measure is limited to estimate accurately the depth map for diverse type of real objects. To address this problem, we develop Optimal Composite Depth (OCD) function through genetic programming (GP) for accurate depth estimation. The OCD function is constructed by optimally combining the primary information extracted using one/or more focus measures. The genetically developed composite function is then used to compute the optimal depth map of objects. The performance of the developed nonlinear function is investigated using both the synthetic and the real world image sequences. Experimental results demonstrate that the proposed estimator is more useful in computing accurate depth maps as compared to the existing SFF methods. Moreover, it is found that the heterogeneous function is more effective than homogeneous function.

Effect of annealing treatment on the uniformity of CeO2/TiO2 bilayer resistive switching memory devices

M. Ismail,A.M. Rana,S.-U. Nisa,F. Hussain,M. Imran,K. Mahmood,I. Talib,E. Ahmed,D.H. Bao 한국물리학회 2017 Current Applied Physics Vol.17 No.10

Bilayer CeO2/TiO2 films with high-k dielectric property were prepared by rf magnetron sputtering technique at room temperature. Effect of annealing treatment on resistive switching (RS) properties of bilayer CeO2/TiO2 films in O2 ambient at different temperature in the range of 350e550 C was investigated. Our results revealed that the bilayer films had good interfacial property at 500 C and this annealing temperature is optimum for different RS characteristics. Results showed that bilayer CeO2/TiO2 film perform better uniformity and reliability in resistive switching at intermediate temperature (i.e. 450 C and 500 C) instead of low and high annealing temperature (i.e. 350 C and 550 C) at which it exhibits poor crystalline structure with more amorphous background. Less Gibbs free energy of TiO2 as compared to CeO2 results in an easier re-oxidation of the filament through the oxygen exchange with TaN electrode. However, the excellent endurance property (>2500 cycles), data retentions (105 s) and good cycle-to-cycle uniformity is observed only in 500 C annealed devices. The plots of cumulative probability, essential memory parameter, show a good distribution of Set/Reset voltage.

3D shape recovery from image focus using kernel regression in eigenspace

Mahmood, M.T.,Choi, T.S. Butterworths ; Elsevier Science Ltd 2010 Image and vision computing Vol.28 No.4

Shape from focus (SFF) is one of the optical passive methods for three dimensional (3D) shape recovery of an object from its two dimensional (2D) images. The focus measure plays important role in SFF algorithms. Mostly, conventional focus measures are based on gradient, so their performance is restricted under noisy conditions. Moreover, SFF methods also suffer from loss of focus information due to discreteness. This paper introduces a new SFF method based on principal component analysis (PCA) and kernel regression. The focus values are computed through PCA by considering a sequence of small 3D neighborhood for each object point. We apply unsupervised regression through Nadaraya and Watson Estimate (NWE) on depth values to get a refined 3D shape of the object. It reduces the effect of noise within a small surface area as well as approximates the accurate 3D shape by exploiting the depth dependencies in the neighborhood. Performance of the proposed scheme is investigated in the presence of different types of noises and textured areas. Experimental results demonstrate effectiveness of the proposed approach.