Hollow fiber (HF) membrane fabrication: A review on the effects of solution spinning conditions on morphology and performance

ABDUL LATIF AHMAD,Tunmise A. Otitoju,Boon S. Ooi 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.70 No.-

HF spinning is a potential configuration in membrane technology due to its self-supporting propertiesand high productivity per unit volume. The fabrication of HF membrane is affected by many parametersand it is important to explore the effect of these parameters on membrane properties. The amount ofresearches on traveling distance are minimal and inadequate to conclude their influence onfiberproperties. The draw ratio has always been neglected (often taken as 1), cannot in most cases equal to 1 asit is influenced by take-up speed, dopeflowrate and solution. Future insights on the above mentionedparameters are important.

Process modeling and optimization studies of high pressure membrane separation of CO2 from natural gas

ABDUL LATIF AHMAD,Jimoh Kayode Adewole 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.10

Process design and optimization methodology for high pressure membrane removal of CO2 from natural gas was developed. An approximate model based on plasticization pressure and permeability parameters at plasticization was proposed for quick evaluation of membrane materials for the high pressure operation. The model was derived by applying the partial immobilization assumption to the fundamental model of solution - diffusion mechanism along with a modified upper-bound curve. About ninety membranes obtained from literature were used to illustrate this methodology. The best three were selected for detailed process modeling and optimization. Process optimization was achieved via non-linear programming constraint optimization model. Gas processing cost was used as the objective function, while plasticization pressure and the CO2 concentration in the feed were used as the constraints. Membrane of 6FDA-durene had the lowest annual gas processing cost while 6FDA-DAM : DABA 2 : 1 had the highest optimum product purity.

Optimization of PES/ZnO mixed matrix membrane preparation using response surface methodology for humic acid removal

ABDUL LATIF AHMAD,Abdullah Adnan Abdulkarim,Suzylawati Ismail,Ooi Boon Seng 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.3

The application of response surface methodology (RSM) in preparation and optimization of membranes is important in order to reduce the effort and time needed to achieving an optimum performance. RSM was used to develop an optimum polyethersulfone (PES)/ZnO mixed matrix (MM) membrane for humic acid removal. The MMs were synthesized by dispersing various amounts of hydrophilic ZnO nanoparticles (NPs) into a solution containing PES, polyvinylpyrrolidone (PVP) and dimethylacetamide (DMAc). Flat sheet MM membranes were prepared via the phase inversion method using the central composite design (CCD). The effects of four preparation parameters, such as PES, ZnO, PVP weight percentages and solvent evaporation time, were investigated. Pure water flux (PWF), humic acid flux (HAF) and humic acid rejection (HAR) were selected as a model responses. It was shown that PES and PVP were mainly affected on both PWF and HAF. Furthermore, the interaction effect between PES and ZnO-NPs shows a significant effect on PWF, while the quadratic effects of both solvent’s evaporation time and ZnO-NPs weight percentage coupled with the interaction effect between PES and PVP weight percentage shows the most significant parameters that affects HAR. The optimization method was subjected to maximize all of the PWF, HAF and HAR. It was also determined that the optimized membrane can be synthesized from a solution containing 17.25 wt% PES, 3.62 wt% ZnO and 3.75 wt% PVP with 15 s of solvent evaporation time. The optimum values of PWF, HAF and HAR were 222.3 (L/m2 h), 94.7 (L/m2 h), and 96.34%, respectively. Thus, it can be concluded that the CCD technique is capable of optimizing PES-ZnO membrane performance.

Critical Impact Energy for Spalling, Tunnelling and Penetration of Concrete Slab impacted with Hard Projectile

Qadir Bux alias Imran Latif,Ismail Abdul Rahman,Ahmad Mujahid Ahmad Zaidi,Kamran Latif 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.1

Penetration is the basic element of designing protective concrete structure against the local impact damage of hard missile. Impactenergy is the dominant cause of damage in moving accidents. When hard projectile collides with concrete target, it is the impactenergy of the projectile that makes concrete target to deform. Therefore, it is vital to study critical impact energy required to causespenetration. An analytical model is developed to predict the required critical impact energy for maximum penetration without reareffects in concrete slabs when it is impacted with hard projectile. The nose shape factor Ni also has been introduced with inclusion ofempirical friction factor Nf, as modification in Chen & Li nose shape factor for ogive nose hard projectile. The newly developedanalytical model and nose shape factor Ni is examined for CRH = 2.0, CRH = 3.0, and CRH = 4.25. It was found that the predictedresults from analytical model with nose shape Ni are in close relation with experimental data in all cases as compared to predictedresults with traditional Li and Chen nose shape N*. In, General, the analytical model generates encouraging prediction which isconsistent and follows a general trend of experimental results.

Diversity of pollinators and their role in the pollination biology of chickpea, Cicer arietinum L. (Fabaceae)

Abdul Latif,Saeed Ahmad Malik,Shafqat Saeed,Naeem Iqbal,Qamar Saeed,Khalid Ali Khan,Chen Ting,Hamed A. Ghramh 한국응용곤충학회 2019 Journal of Asia-Pacific Entomology Vol.22 No.2

Chickpea (Cicer arietinum L.) is an important source of food for people worldwide. In the current study, we studied its pollination biology with special reference to floral visitors along with their visitation rate, frequency and pollen load during 2012 and 2013. We also explored the effect of floral visitors on the capsule weight, seed weight, seed numbers and seed germination. Results revealed three bees, two wasps, five flies, one moth and three butterfly species on the flowers of chickpea. Apis dorsata, A. florea, Amegilla sp. and Eristalinus aeneus were the major species with 434–474, 223–311, 69–74 and 81–136 individuals, respectively in both years. Floral visitors differed significantly in term of visitation frequency with A. florea as the most frequent visitor (9.13–9.86 visits/flower/5 min) followed by E. aeneus (5.43–5.58 visits/flower/5 min) and A. dorsata (1.72–2.31 visits/ flower/5 min) in both years. Similarly, A. florea had statistically highest visitation rate (16.85–19.99 flowers visited/min) followed by E. aeneus (9.73–10.68 flowers visited/min). A. dorsata had significantly higher pollen load on its body (84629–85,104 pollen grains) followed by A. florea (64940–65,135 pollen grains) and Amegilla sp. (64020–65,120 pollen grains). The open-pollinated flowers had significantly higher capsule weight (0.27 ± 0.01 g), seed weight (0.18 ± 0.01 g), seed numbers (1.67 ± 0.07 seeds) and seed germination (95 ± 1.38%) as compared to flowers deprived of pollinators in cages. The results suggested A. florea, A. dorsata and E. aeneus could be effective pollinators of chickpea. Hence these three species can be properly utilized on commercial scale to increase crop yield.

Pollination biology of Callistemon viminalis (Sol. Ex Gaertn.) G. Don (Myrtaceae), Punjab, Pakistan

Abdul Latif,Naeem Iqbal,Muhammad Ejaz,Saeed Ahmad Malik,Allah Bakhsh Gulshan,Abid Mahmood Alvi,Khaliq Dad 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.2

A research was conducted to find out the floral traits and pollinator's community of bottle brush (Callistemon viminalis: Myrtaceae). Total numbers of pollen grains, pollen grain viability, stigma receptivity, nectar volume and nectar concentration, numbers of ovules and pollen/ovule ratio were recorded. The pollinators' abundance, visitation rate and frequency were also observed. In field experiment, capsule weight, seed setting and seed numbers in open and caged flowers were also evaluated. The results revealed a total of 128,139 pollen grains/ flower. Among total pollen grains, viable pollen grains were 84.3% and non-viable were 15.69%. There were 275 ovules/flower and pollen ovule ratio was 472.50. Stigma receptivity was decreased with the age of the flowers and stigma remained receptive for about 6 days. The nectar volume and nectar concentration were 13 μL and 29%, respectively. The flowers were visited by nine Hymenopteran, four Lepidopteran, one Dipteran and one bird species. Among all pollinators, bees represented the most abundant species (1290) and showed the highest visitation rate (3.6–13.8 numbers of flowers/min) and visitation frequency (0.22–1.92 individuals/ branch/5 min). Open-pollinated flowers showed statistically higher capsule weight (0.0824 ± 0.001), seed setting (0.052 ± 0.0001) and seed numbers (242.4 ± 2.87) as compared to flowers in cages.

Salinity Stress Resistance Offered by Endophytic Fungal Interaction Between Penicillium minioluteum LHL09 and Glycine max. L

( Khan Abdul Latif ),( Muhammad Hamayun ),( Nadeem Ahmad ),( Javid Hussain ),( Sang Mo Kang ),( Yoon Ha Kim ),( Muhammad Adnan ),( Dong Sheng Tang ),( Muhammad Waqas ),( Ramalingam Radhakrishnan ),( Y 한국미생물 · 생명공학회 2011 Journal of microbiology and biotechnology Vol.21 No.9

Endophytic fungi are little known for their role in gibberellins (GAs) synthesis and abiotic stress resistance in crop plants. We isolated 10 endophytes from the roots of field-grown soybean and screened their culture filtrates (CF) on the GAs biosynthesis mutant rice line - Waito-C. CF bioassay showed that endophyte GMH-1B significantly promoted the growth of Waito-C compared with controls. GMH-1B was identified as Penicillium minioluteum LHL09 on the basis of ITS regions rDNA sequence homology and phylogenetic analyses. GC/MS-SIM analysis of CF of P. minioluteum revealed the presence of bioactive GA4 and GA7. In endophyte-soybean plant interaction, P. minioluteum association significantly promoted growth characteristics (shoot length, shoot fresh and dry biomasses, chlorophyll content, and leaf area) and nitrogen assimilation, with and without sodium chloride (NaCl)-induced salinity (70 and 140 mM) stress, as compared with control. Field-emission scanning electron microcopy showed active colonization of endophyte with host plants before and after stress treatments. In response to salinity stress, low endogenous abscisic acid and high salicylic acid accumulation in endophyte-associated plants elucidated the stress mitigation by P. minioluteum. The endophytic fungal symbiosis of P. minioluteum also increased the daidzein and genistein contents in the soybean as compared with control plants, under salt stress. Thus, P. minioluteum ameliorated the adverse effects of abiotic salinity stress and rescued soybean plant growth by influencing biosynthesis of the plant`s hormones and flavonoids.

Gibberellin-Producing Endophytic Fungi Isolated from Monochoria vaginalis

( Nadeem Ahmad ),( Muhammad Hamayun ),( Sumera Afzal Khan ),( Abdul Latif Kban ),( In Jung Lee ),( Dong Hyun Shin ) 한국미생물 · 생명공학회 2010 Journal of microbiology and biotechnology Vol.20 No.12

The role of endophytic fungi in plant growth and development is well documented. However, endophytic fungi with growth promotion capacity have never been isolated from weeds previously. In the current study, we isolated 8 fungal endophytes from the roots of Monochoria vaginalis, a serious weed of rice paddy in Korea. These isolates were screened on Waito-C, in order to identify plant growth promoting metabolites. Two fungal isolates (M5.A & M1.5) significantly promoted the plant height and shoot length of Waito-C during preliminary screening experiments. The culture filtrates (CFs) of M5.A and M1.5 also promoted the shoot length of Echinocloa crusgalli. Gibberellins (GAs) analysis of the CFs of M5.A and M1.5 showed that these endophytic fungi secrete higher quantities of GAs as compared with wild-type G. fujikuroi KCCM12329. The CF of M5.A contained bioactive GAs (GA3, 2.8 ng/ml; GA4, 2.6 ng/ml, and GA7, 6.68 ng/ml) in conjunction with physiologically inactive GA9 (1.61 ng/ml) and GA24 (0.18 ng/ml). The CF of M1.5 contained physiologically active GAs (GA3, 1.64 ng/ml; GA4, 1.37 ng/ml and GA7, 6.29 ng/ml) in conjunction with physiologically inactive GA9 (3.44 ng/ml), GA12 (0.3 ng/ml), and GA24 (0.59 ng/ml). M5.A and M1.5 were identified as new strains of Penicillium sp. and Aspergillus sp., respectively, based on their 18S rDNA sequence homology and phylogenetic analysis.

Evaluation of Humic Acid Application Methods for Yield and Yield Components of Mungbean

Waqas, Muhammad,Ahmad, Bashir,Arif, Muhammad,Munsif, Fazal,Latif Khan, Abdul,Amin, Muhammad,Kang, Sang-Mo,Kim, Yoon-Ha,Lee, In-Jung 'Scientific Research Publishing, Inc.' 2014 American journal of plant sciences Vol.5 No.15

New Butyrylcholinesterase Inhibitory Steroid and Peroxy Acid from Leucas urticifolia

Fatima, Itrat,Ahmad, Ijaz,Anis, Itrat,Malik, Abdul,Afza, Nighat,Iqbal, Lubna,Latif, Mehreen 대한약학회 2008 Archives of Pharmacal Research Vol.31 No.8

A new steroid leucisterol (1) and a new peroxy acid urticic acid (2) along with methoxybenzyl benzoate (3), 4-hydroxy benzoic acid (4), $\beta$-sitosterol (5), and ursolic acid (6), have been isolated from the chloroform soluble fraction of the whole plant of Leucas urticifolia. Their structures were elucidated on the basis of nuclear magnetic resonance (1D and 2D NMR) spectral data. Leucisterol showed potent inhibitory activity against butyrylcholinesterase enzyme.