Polyaniline-engineered zinc sulphide nanocomposite as a highly efficient electrocatalyst for the oxygen evolution process

Alenad Asma M.,Fatima Sofia,Khalid Usman,Bano Nigarish,Abid Abdul Ghafoor,Manzoor Sumaira,Farid Hafiz Muhammad Tahir,Messali Mouslim,Alzahrani Huda A.,Taha Taha Abdel Mohaymen 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.5

Hydrogen is the ideal future fuel, since it is clean, saves energy, and is abundant in nature. Though there are several methods for producing hydrogen, only a few of them are environmentally friendly. To employ water electrolysis to make hydrogen and solve the energy shortage problem, highly active electrocatalysts must be created. Zinc sulphide/polyaniline (ZnS/PANI) nanocomposite was successfully produced using a straightforward two-step coprecipitation and polymerization procedure. Different analyses were used to characterize the fabricated materials. The findings show that the ZnS/PANI nanocomposite's morphology has a consistent porous shape, and the electrical structure of the active sites determines how well catalysts can make contact with the intermediates. Multiple attempts have been made to create the most affordable, functional electrocatalyst for oxygen evolution reactions (OER). However, clean energy production from such materials is sluggish. In comparison to pure PANI nanofibers (143.14 m2 g−1 and 0.4827 nm) and ZnS nanostructures (249.85 m2 g−1 and 0.4224 nm), the composite ZnS/PANI displays a greater Brunauer–Emmett–Teller (BET) surface area around 372.65 m2 g−1 along with nanoporous size of 0.393 nm due to the interaction, which provides distinctive features in contrast to ZnS and PANI. Synergistically, composite ZnS/PANI indicates lower overpotentials of 132 mV for oxygen evolution performance at 10 mA cm−2. An improved OER activity is observed by composite ZnS/PANIs as high current density, lower overpotential and reduced Tafel value of 53 mV dec−1. This catalyst also exhibited a significant double-layer capacitance and a large electrochemically active surface area. ZnS/PANI is a magnificent electrocatalyst for oxygen evolution.

The effect of RGO on dielectric and energy harvesting properties of P(VDF-TrFE) matrix by optimizing electroactive β phase without traditional polling process

Habibur, Rahaman Md,Yaqoob, Usman,Muhammad, Sheeraz,Uddin, A.S.M.Iftekhar,Kim, Hyeon Cheol Elsevier 2018 Materials chemistry and physics Vol.215 No.-

<P><B>Abstract</B></P> <P>This study explores the role of RGO in improving the energy harvesting potentiality of P(VDF-TrFE) matrix without applying the conventional polling process. Five different piezoelectric sheets were prepared by varying the RGO contents in P(VDF-TrFE) matrix to realize its optimum concentration in the matrix. The effect of RGO on the electroactive polar beta (<I>β</I>) phase of P(VDF-TrFE) was investigated through the X-ray diffraction (XRD) pattern and the Fourier transform infrared spectroscopy (FT-IR). To elaborate the RGO role, dielectric properties of the as-prepared piezoelectric sheets were also checked over the frequency range of 1 kHz–100 kHz at room temperature. Finally, these piezoelectric sheets were used to fabricate the piezoelectric nanogenerators (PENGs) devices. Among the fabricated PENGs, the PENG with 0.1% RGO contents reveals the maximum open circuit voltage of 2.4 V and highest peak of short-circuit current around 0.8 μA at an applied force of 2 N. Moreover, it exhibits the highest output power of 3.2 μW at 1.8 MΩ load resistance, all the outputs were recorded without applying polling process. It was estimated that our fabricated self-poled, flexible piezoelectric nano-generator can be a useful candidate to powering futuristic nano-devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The effect of RGO nanosheets on the electroactive polar <I>β</I> phase of P(VDF-TrFE) was explored. </LI> <LI> RGO nanofillers act as a polling medium in the P(VDF-TrFE) matrix. </LI> <LI> Enhancement in energy harvesting was observed with increasing of RGO concentration. </LI> </UL> </P>

Biochar, a potential hydroponic growth substrate, enhances the nutritional status and growth of leafy vegetables

Awad, Y.M.,Lee, S.E.,Ahmed, M.B.M.,Vu, N.T.,Farooq, M.,Kim, I.S.,Kim, H.S.,Vithanage, M.,Usman, A.R.A.,Al-Wabel, M.,Meers, E.,Kwon, E.E.,Ok, Y.S. Butterworth-Heinemann, Ltd 2017 Journal of cleaner production Vol.156 No.-

A hydroponics system developed using a nutrient film technique was used to evaluate the effectiveness of rice husk biochar (RB) alone or in combination with perlite (PL) as substrates for increasing the growth of leafy vegetables compared with that of PL. Seedlings of cabbage, dill, mallow, red lettuce, and tatsoi were grown hydroponically in PL, RB, and PL + RB (1:1 ratio of PL to RB, v/v) substrates for a 30-d under optimal environmental conditions in a greenhouse. Shoot length and fresh/dry masses of cabbage, dill, and red lettuce plants grown in RB substrate were decreased by 49% on average compared to those plants grown in PL substrate. In contrast, PL + RB substrate led to approximately 2-fold increases in shoot length, number of leaves, and fresh/dry masses of leafy vegetable plants compared with those grown in PL substrate. Foliar nutritional composition (Ca, Mg, K, Na, Mn, Fe, and Zn) and nitrogen status (SPAD index) of plants grown in PL + RB and PL substrates suggested the presence of optimal growth conditions for ensuring optimum yield with high quality. In addition, RB substrate contributed to respective increases of 1.2-3.5-fold in leaf K, Mg, Mn, and Zn contents in most vegetable plants compared with those grown in PL substrate. The RB alone or in combination with PL substrates decreased algal growth in the nutrient solutions as confirmed by scanning electron micrographs of microalgae on the RB surface. The results also indicated that use of PL + RB hydroponic substrate could be an alternative and effective technology for the better management of unwanted algal growth in nutrient solutions and high production of leafy vegetables.

Toxicity of synthetic chelators and metal availability in poultry manure amended Cd, Pb and As contaminated agricultural soil

Usman, A.R.A.,Almaroai, Yaser.A.,Ahmad, M.,Vithanage, M.,Ok, Y.S. Elsevier Scientific Pub. Co 2013 Journal of hazardous materials Vol.262 No.-

Chelating agents added to contaminated soils may increase solubility and phytoextraction efficiency of soil metals. However, they can create negative effects on soil biological quality. A 90-day incubation experiment was conducted to evaluate mixed effects of chelating agents and poultry manure on changes in available Cd, Pb and As, CO<SUB>2</SUB>-C efflux, microbial biomass C, dissolved organic C (DOC), and N mineralization in metal-polluted agricultural soil. Application of poultry manure resulted in a considerable increase in soil pH, DOC, CO<SUB>2</SUB>-C efflux, net N mineralization, net N nitrification, and microbial biomass C compared to those in unmanured soil. Availability of arsenic increased twice in manure amended soil due to changes in pH and DOC. However, adding poultry manure did not affect the concentrations of available Pb and Cd compared to those in control soil. Chelating agents increased CO<SUB>2</SUB>-C efflux, DOC, and metal availability but decreased microbial biomass C and net N mineralization. Maximum decrease in microbial biomass C, net N mineralization, and net N nitrification, was observed in EDTA applied soil possibly due to high metal availability to soil microorganisms. Overall results revealed that the application of synthetic chelators in combination with poultry manure enhances available As and demonstrates better environment for soil biota.

Adsorption Kinetics of Acid Red on Activated Carbon Web Prepared from Acrylic Fibrous Waste

M. Salman Naeem,Saima Javed,Vijay Baheti,Jakub Wiener,M. Usman Javed,Syed Zameer Ul Hassan,Adnan Mazari,Jawad Naeem 한국섬유공학회 2018 Fibers and polymers Vol.19 No.1

In this work, activated carbon (AC) web was prepared using physical activation under the layer of charcoal in high temperature furnace. The carbonization of acrylic fibrous waste was performed at different temperatures (800 ℃, 1000 ℃, and 1200 ℃) with heating rate of 300 oC/h and at different holding time. At 1200 ℃, the heating rate of 300 ℃/h and no holding time provided better results of surface area as compared to carbonization at 800 ℃ and 1000 ℃. The activated carbonweb (AC) prepared at 1200 oC was used for removal of Acid Red 27 dye from aqueous media by varying different parameters like initial concentration of dye, stirring speed, adsorbent dosage, and pH. The results were evaluated using non-linear forms of Langmuir and Freundlich isotherms. The Freundlich isotherm was found to describe the results more effectively because of non-homogenous surface of activated carbon web. Further, the kinetics of adsorption was examined using linear and nonlinearforms of pseudo 1st order and pseudo 2nd order.

Initial Ranging and Detection Enhacement and Time Offset Calculation for Synchronization in 802.16e Systems by Hybrid Detection Method

M Usman Afzal(우스만아프잘),Jong Min Park(박종민),Sung Ho Cho(조성호) 대한전기학회 2008 정보 및 제어 심포지엄 논문집 Vol.2008 No.1

Initial Ranging Detection and Synchronization is suggested for IEEE 802.16e OFDMA Systems. However ranging is vulnerable to the channel selectivity and other user's interference at low SNR. This paper presents enhanced ranging scheme that improves ranging detection process using the combine multiple FFT blocks and cope with channel selectivity and other user's interference at low SNR. Based on the ranging detection timing offset is calculated for synchronization.

Monitoring the Bond-slip Behavior Between Concrete and CFRP Laminate Using Acoustic Emission

Usman, Hanif, M.(우스만 하니프 엠),Tran, Hai Van(쩐 하이반),Khol, Senghong(콜 생홍),Seo, Soo-Yeon(서수연) 한국콘크리트학회 2023 한국콘크리트학회 학술대회 논문집 Vol.35 No.2

Thermo-economic optimization of Regenerative Organic Rankine Cycle for waste heat recovery applications

Imran, M.,Park, B.S.,Kim, H.J.,Lee, D.H.,Usman, M.,Heo, M. Pergamon ; Elsevier Science Ltd 2014 Energy conversion and management Vol.87 No.-

Organic Rankine Cycle (ORC) is low grade and waste heat conversion technology. The current article deal with the thermo-economic optimization of basic ORC and regenerative ORC for waste heat recovery applications under constant heat source condition. Thermal efficiency and specific investment cost of basic ORC, single stage regenerative and double stage regenerative ORC has been optimized by using Non-dominated Sorting Genetic Algorithm-II (NSGA-II). Maximum thermal efficiency and minimum specific investment cost were selected as objective functions and relative increase in thermal efficiency and cost has been analyzed taking the basic ORC as base case. The constraint set consist of evaporation pressure, superheat, pinch point temperature difference in evaporator and condenser. The optimization was performed for five different working fluids. The optimization result show that R245fa is best working under considered conditions and basic ORC has low specific investment cost and thermal efficiency compared to regenerative ORC. R245fa is low boiling organic fluid, which has high degree of thermal stability and compatible with common construction materials of ORC. The average increase in thermal efficiency from basic ORC to single stage regenerative ORC was 1.01% with an additional cost of 187$/kW while from basic ORC to double stage regenerative ORC was 1.45% with an average increase in cost of 297$/kW. The sensitivity analysis was also performed to investigate the effect of operating conditions which show that evaporation pressure has promising effect on thermal efficiency and specific investment cost.

AN ALTERNATIVE q-ANALOGUE OF THE RUCINSKI-VOIGT NUMBERS

Bent-Usman, Wardah M.,Dibagulun, Amerah M.,Mangontarum, Mahid M.,Montero, Charles B. Korean Mathematical Society 2018 대한수학회논문집 Vol.33 No.4

In this paper, we define an alternative q-analogue of the $Ruci{\acute{n}}ski$-Voigt numbers. We obtain fundamental combinatorial properties such as recurrence relations, generating functions and explicit formulas which are shown to be q-deformations of similar properties for the $Ruci{\acute{n}}ski$-Voigt numbers, and are generalizations of the results obtained by other authors. A combinatorial interpretation in the context of A-tableaux is also given where convolution-type identities are consequently obtained. Lastly, we establish the matrix decompositions of the $Ruci{\acute{n}}ski$-Voigt and the q-$Ruci{\acute{n}}ski$-Voigt numbers.

A novel tri-layer flexible piezoelectric nanogenerator based on surface- modified graphene and PVDF-BaTiO₃ nanocomposites

Yaqoob, Usman,Uddin, A.S.M. Iftekhar,Chung, Gwiy-Sang Elsevier 2017 APPLIED SURFACE SCIENCE - Vol.405 No.-

<P><B>Abstract</B></P> <P>The fabrication and characterization of a novel tri-layer piezoelectric nanogenerator (PNG) based on poly(vinylidene fluoride) (PVDF), barium titanate (BTO), and surface-modified <I>n</I>- type graphene (<I>n</I>-Gr) have been investigated. The <I>n</I>-Gr, with its majority of negative charge carriers, plays a vital role in enhancing the energy-harvesting performance by aligning the dipoles in one direction. The tri-layer structure obtains by stacking two layers of PVDF-BTO nanocomposite films, one on each side of the <I>n</I>-Gr layer. The fabricated tri-layer PNG shows a maximum output voltage of 10V (pk-pk) along with a current of 2.5μA (pk-pk) at an applied force of 2N. Furthermore, the PNG Exhibits 5.8μW instantaneous power at 1MΩ load resistance. Moreover, the fabricated device demonstrated good stability even after 1000 pressing–releasing cycles. This novel tri-layer PNG structure can opens a promising avenue for future piezoelectric generating technologies.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Tri-layer structure was achieved by stacking two layers of PVDF-BTO films, on one each side of n-graphene layer. </LI> <LI> The role of n-graphene in increasing the energy harvesting property of PNG has been explored. </LI> <LI> Third layer of PVDF-BTO was used to block the charge recombination between upper electrode and n-graphene. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Tri-layer piezoelectric nanogenerator schematic diagram and working mechanism.</P> <P>[DISPLAY OMISSION]</P>