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Microscopy Observations of Habitable Space in Biochar for Colonization by Fungal Hyphae From Soil

Journal of Integrative Agriculture 2014年第3期13卷 483-490页

作者： Noraini M jaafar Peta L Clode Lynette K Abbott Soil Biology and Molecular Ecology Group School of Earth and Environment and UWA Institute of Agriculture The University of Western Australia Department of Land Management Faculty of Agriculture Universiti Putra Malaysia Centre for Microscopy Characterisation and Analysis The University of Western Australia

Biochar is a potential micro-environment for soil microorganisms but evidence to support this suggestion is limited. We explored imaging techniques to visualize and quantify fungal colonization of habitable spaces in a biochar made from a woody feedstock. In addition to characterization of the biochar, it was necessary to optimize preparation and observation methodologies for examining fungal colonization of the biochar. Biochar surfaces and pores were investigated using several microscopy techniques. Biochar particles were compared in soilless media and after deposition in soil. Scanning electron microscopy （SEM） observations and characterization of the biochar demonstrated structural heterogeneity within and among biochar particles. Fungal colonization in and on biochar particles was observed using light, fluorescence and electron microscopy. Fluorescent brightener RR 2200 was more effective than Calcofluor White as a hyphal stain. Biochar retrieved from soil and observed using fluorescence microscopy exhibited distinct hyphal networks on external biochar surfaces. The extent of hyphal colonization of biochar incubated in soil was much less than for biochar artificially inoculated with fungi in a soilless medium. The location of fungal hyphae was more clearly visible using SEM than with fluorescence microscopy. Observations of biochar particles colonized by hyphae from soil posed a range of difficulties including obstruction by the presence of soil particles on biochar surfaces and inside pores. Extensive hyphal colonization of the surface of the biochar in the soilless medium contrasted with limited hyphal colonization of pores within the biochar. Both visualization and quantification of hyphal colonization of surfaces and pores of biochar were restricted by two-dimensional imaging associated with uneven biochar surfaces and variable biochar pore structure. There was very little colonization ofbiochar from hyphae in the agricultural soil used in this study.

关键词： biochar agriculture fungi soil habitable pore space microscopy

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Cost Optimized Non-Contacting Experimental Modal Analysis Using a Smartphone

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Sound & Vibration 2020年第4期54卷 225-236页

作者： jaafar Hallal Mohammad Hammoud Mahmoud Fakih Ali Hallal Mechanical Engineering Department Faculty of EngineeringLebanese UniversityBeirutLebanon SDM Research Group Mechanical Engineering DepartmentInternational University of BeirutBeirutLebanon Mechanical Engineering Department Lebanese International UniversityBekaaLebanon Civil Engineering Department Faculty of EngineeringLebanese UniversityBeirutLebanon

The vibrations behavior analysis is an essential step in the mechanical design *** methods such as analytical modelling,numerical analysis and experimental measurements can be used for this ***,the numerical or analytical models should be validated through experimental measurements,usually *** paper introduces an inexpensive smartphone as an accurate,non-intrusive vibrations’behavior measurement *** experimental measurement procedure based on the video processing method is *** procedure allows the measurement of the natural frequencies and the mode shapes of a vibrating structure,simply by using a smartphone built-in *** experimental results are compared to those obtained using an accurate analytical model,where the natural frequencies error is less than 2.7%and the modal assurance criterion is higher than *** order to highlight the obtained results,a comparison has been done using a high quality and high frame per second(fps)camera-based measurement of material *** the highest recovered natural frequency and its associated mode shape depend on the frame per second rate of the recorded video,this procedure has great potential in low frequencies problems such as for big structures like buildings and *** validated technique re-introduces the personal smartphone as an accurate inexpensive non-contacting vibration measurement tool.

关键词： Experimental measurement motion magnification smartphone vibrations mode shape natural frequency

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Effect of Lead-Rubber Bearing Isolators in Reducing Seismic Damage for a High-Rise Building in Comparison with Normal Shear Wall System

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Structural Durability & Health Monitoring 2021年第3期15卷 247-260页

作者： Mahmoud Fakih jaafar Hallal Hassan Darwich Hala Damerji Faculty of Engineering Lebanese UniversityBeirutLebanon Laboratory of Composite Materials for Construction(LMC2) University of LyonLyonFrance Faculty of Engineering ArtsSciences and Technology University in LebanonBeirutLebanon

Seismic earthquakes are a real danger for the construction evolution of high rise *** rate of earthquakes around the world is noteworthy in a wide range of construction *** this study,we present the dynamic behavior of a high-rise RC building with dynamic isolators(lead-rubber-bearing),in comparison with a traditional shear wall system of the same *** isolation has been introduced in building construction to increase the structural stability and to protect the non-structural components against the damaging effects of an *** order to clarify the influence of incorporating lead rubber bearing isolators in the seismic response and in reducing seismic damages;a comparative study is performed between a fixed base system(shear wall system)and an isolated base system(Lead Rubber Bearing)on an irregular high rise reinforced concrete(RC)building located in Beirut consisting of 48 storeys almost asymmetric *** this purpose,a non-linear analysis of a real earthquake acceleration record(EI Centro seismic signal)is conducted,so that the mode shapes,the damping ratio and the natural frequencies of the two models are obtained using ETABS *** results prove a substantial elongation of the building period,as well as a reduction in the building displacement,the roof acceleration,the inter-storey drift ratio and the base shear force of isolated building relative to fixed-base *** study proves that this technology is applicable to high rise buildings with acceptable results.

关键词： Seismic damage non-linear time history analysis high-rise RC building seismic response analysis lead rubber bearing

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Synthesis of two-dimensional lead sheets by spark discharge in liquid nitrogen

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Particuology 2018年第5期16卷 152-159页

作者： Ahmad Hamdan Hiba Kabbara Cedric Noel jaafar Ghanbaja Abdelkrim Redjaimia Thierry Belmonte Universite de Lorraine lnstitutJean tamourUMR CNRS 7198Nancy F-54042France CNRS lnstitutJean LamourUMR CNRS 7198Nancy F-54042France

A simple method to synthesise hexagonal lead sheets,which belong to the class of two-dimensional materials,is *** objects are collected on a substrate located under two lead electrodes, between which nanosecond-pulsed spark discharges are ignited in liquid *** hexagonal sheets are single crystals produced by gas phase *** nitrogen completely evaporates,the sheets change to PbO2by oxidation in *** oxidation process induces stress that pleats the uppermost sheets or open cracks at the *** thickness of the individual objects typically varies from 4to *** the number of discharges is more than about 2000,in addition to sheets,two types of PbO2 sticks start to form:bundles composed of nanosticks (length 5p.m and diameter 50nm)and isolated sticks (length 20μm and diameter 500nm).These new nanostructures mainly form because of the way the discharge erodes the lead ***,anisotropic erosion driven by the orientation of the crystallographic planes of the lead crystals produces octahedra and nanosticks,and the nanosticks grow on the electrode surfaces as discharge *** about 2000discharges,the nanosticks are sufficiently long that they can be easily broken,probably by mechanical stress,and they fall onto the underlying substrate.

关键词： Discharge in hquids Plasma-surface interaction Nanopamcles Liquid nitrogen Lead

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Penta-P2X （X=C, Si） monolayers as wide-bandgap semiconductors： A first principles prediction

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Frontiers of physics 2018年第3期13卷 101-109页

作者： Mosayeb Naseri Shiru Lin jaafar Jalilian Jinxing Gu Zhongfang Chen Department of Physics Kermanshah Branch Islamic Azad University Kermanshah Iran Department of Chemistry University of Puerto Rico Rio Piedras Campus San Juan PR 00931 USA Young Researchers and Elite Club Kermanshah Branch Islamic Azad University Kermanshah Iran

By means of density functional theory computations, we predicted two novel two-dimensional （2D） nanolnaterials, namely P2X （X=C, Si） monolayers with pentagonal configurations. Their structures, stabilities, intrinsic electronic, and optical properties as well as the effect of external strain to the elec- tronic properties have been systematically examined. Our computations showed that these P2C and P2Si monolayers have rather high thermodynamic, kinetic, and thermal stabilities, and are indirect semiconductors with wide bandgaps （2.76 eV and 2.69 eV, respectively） which can be tuned by an external strain. These monolayers exhibit high absorptions in the UV region, but behave as almost transparent layers for visible light in the electromagnetic spectrum. Their high stabilities and excep- tional electronic and optical properties suggest them as promising candidates for future applications in UV-light shielding and antireflection layers in solar cells.

关键词： 2D materials density functional calculations wide bandgap semiconductors

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Effects of variations in culture media and hormonal treatments upon callus induction potential in endosperm explant of Barringtonia racemosa L.

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Asian Pacific Journal of Tropical Biomedicine 2016年第2期6卷 143-147页

作者： Nurul Izzati Osman Norrizah jaafar Sidik Asmah Awal Faculty of Applied Sciences Universiti Teknologi MARA Faculty of Plantation and Agrotechnology Universiti Teknologi MARA

Objective: To induce callus from the medicinally valuable species, Barringtonia racemosa L.(B. racemosa) whereby the formation of callus is essential for micropropagation studies and in vitro plant secondary metabolites ***: The callus induction potential in B. racemosa was assessed from endosperm explant cultured on different culture media and plant hormonal treatments. Lloyd and Mc Cown's woody plant medium and Murashige and Skoog's medium were used in the study as culture media. On the other hand, various concentrations and combinations of2,4-dichlorophenoxyacetic acid(1.0–2.0 mg/L) and kinetin(0.5–2.5 mg/L) had been incorporated in the culture media to exert the effects of auxin and cytokinin on callus ***: From the present study, it was found that the profuse [(1.681 ± 0.770) g fresh weight,(0.239 ± 0.239) g dry weight] and friable callus formation was optimally produced with desirable morphology and considerable percentage of callus induction(56.70%) in endosperm explants cultured on 1.0 mg/L 2,4-dichlorophenoxyacetic acid and 1.5 mg/L kinetin in Murashige and Skoog's ***: A reliable protocol for inducing callus formation of profuse and friable morphology in endosperm explant of B. racemosa had therefore been successfully established.

关键词： Callus induction Barringtonia racemosa Plant growth regulators 2,4-Dichlorophenoxyacetic acid Kinetin Lloyd and Mc Cown’s woody plant medium Murashige and Skoog’s medium

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Soil Microbial Responses to Biochars Varying in Particle Size,Surface and Pore Properties

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Pedosphere 2015年第5期25卷 770-780页

作者： Noraini M.jaafar Peta L.CLODE Lynette K.ABBOTT Soil Biology and Molecular Ecology Group School of Earth and Environment (M087) and UWA Institute of AgricultureThe University of Western Australia Department of Land Management Faculty of AgricultureUniversiti Putra Malaysia Centre for Microscopy Characterisation and Analysis (M010)The University of Western Australia

Biochars are known for their heterogeneity, especially in pore and surface structure associated with pyrolysis processes and sources of feedstocks. The surface area of biochar is likely to be an important determinant of the extent of soil microbial attachment, whereas the porous structure of biochar is expected to provide protection for soil microorganisms. Potential interactions between biochars from different sources and with different particle sizes were investigated in relation to soil microbial properties in a short-term incubation study. Three particle size （sieved） fractions （0.5-1.0, 1.0-2.0 and 2.0-4.0 mm） from three woody biochars produced from jarrah wood, jarrah and wandoo wood and Australian wattle branches, respectively, were incubated in soil at 25 ℃ for 56 d. Observation by scanning electron microscopy （SEM） and characterisation of pore and surface area showed that all three woody biochars provided potential habitats for soil microorganisms due to their high porosity and surface areas. The biochars were structurally heterogeneous, varying in porosity and surface structure both within and between the biochar sources. After the 56-d incubation, hyphal colonisation was observed on biochar surfaces and in larger biochar pores. Soil clumping occurred on biochar particles, cementing and covering exposed biochar pores. This may have altered surface area and pore availability for microbial colonisation. Transient changes in soil microbial biomass, without a consistent trend, were observed among biochars during the 56-d incubation.

关键词： microbial biomass, microbial colonisation, microbial habitats, porosity scanning electron microscopy, surface structure

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Development of a new connection for precast concrete walls subjected to cyclic loading

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Earthquake Engineering and Engineering Vibration 2017年第1期16卷 97-117页

作者： Ramin Vaghei Farzad Hejazi Hafez Taheri Mohd Saleh jaafar Farah Nora Aznieta Abdul Aziz Civil Department Engineering Faculty University Putra Malaysia Serdang Selangor 43400 Malaysia

The Industrialized Building System （IBS） was recently introduced to minimize the time and cost of project construction. Accordingly, ensuring the integration of the connection of precast components in IBS structures is an important factor that ensures stability of buildings subjected to dynamic loads from earthquakes, vehicles, and machineries. However, structural engineers still lack knowledge on the proper connection and detailed joints o fiBS structure construction. Therefore, this study proposes a special precast concrete wall-to-wall connection system for dynamic loads that resists multidirectional imposed loads and reduces vibration effects （PI2014701723）. This system is designed to connect two adjacent precast wall panels by using two steel U-shaped channels （i.e., male and female joints）. During casting, each joint is adapted for incorporation into a respective wall panel after considering the following conditions： one side of the steel channel opens into the thickness face of the panel; a U-shaped rubber is implemented between the two channels to dissipate the vibration effect; and bolts and nuts are used to create an extension between the two U-shaped male and female steel channels. The developed finite element model of the precast wall is subjected to cyclic loads to evaluate the performance of the proposed connection during an imposed dynamic load. Connection performance is then compared with conventional connections based on the energy dissipation, stress, deformation, and concrete damage in the plastic range. The proposed precast connection is capable of exceeding the energy absorption of precast walls subjected to dynamic load, thereby improving its resistance behavior in all principal directions.

关键词： industrial building system precast concrete structure precast wall connection finite element method nonlinear analysis energy dissipation concrete damage plasticity

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Experimental Modal Damping Identification of a Mechanical Structure Using Video Magnification Technique

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Sound & Vibration 2021年第2期55卷 131-140页

作者： jaafar Hallal Mahmoud Fakih Hala Damerji Mohammad Hammoud Mehdi Chouman Mechanical Engineering Department Faculty of EngineeringLebanese UniversityBeirutLebanon Civil Engineering Department Faculty of EngineeringLebanese UniversityBeirutLebanon Universite Grenoble Alpes CNRSGrenoble INP3SRGrenobleFrance SDM Research Group Mechanical Engineering DepartmentInternational University of BeirutBeirutLebanon Mechanical Engineering Department Lebanese International UniversityBekaaLebanon

Vibration can be introduced in all mechanical fields in our *** try to avoid its negative effect leading in some cases to deformation in the *** researches are dedicated to study the identification of damping especially in multi degree of freedom systems with particular attention to the source of energy *** focus on developing new tools or methods which may be used in real problems to obtain accurate results about the amount(or value)and the location of energy dissipation in the *** aim of this paper is to present an original procedure aims to experimentally determine the modal damping ratio of a mechanical *** proposed procedure consists of extracting the Frequency Response Function of the vibrating system using the video magnification method and then calculate the modal damping ratio using the 3-dB *** experimental measurements are carried out by giving an external force on a cantilever beam,then the modal damping ratios are extracted using motion *** obtained results show a relative error less than 4.2% between the experimental measurements and the analytical calculation for the Frequency Response Function(FRF)*** novelty of the paper is to combine the video magnification technique and the 3dB method in a procedure that aims to experimentally measure the modal damping of a mechanical *** proposed procedure in this paper represents the damping identification as a simple and easy engineering application.

关键词： Vibrations modal damping experimental measurement video magnification

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Biochar-Soil Interactions in Four Agricultural Soils

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Pedosphere 2015年第5期25卷 729-736页

作者： Noraini M.jaafar Peta L.CLODE Lynette K.ABBOTT Soil Biology and Molecular Ecology Group School of Earth and Environment (M087)and UWA Institute of AgricultureThe University of Western Australia Department of Land Management Faculty of AgricultureUniversiti Putra Malaysia Centre for Microscopy Characterisation and Analysis (M010)The University of Western Australia

Soils in south-western Australia are highly weathered and deficient in nutrients for agricultural production. Addition of biochar has been suggested as a mean of improving soil C storage, texture and nutrient retention of these soils. Clay amendment in sandy soils in this region is a management practice used to improve soil conditions, including water repellence. In this study a woody biochar(Simcoa biochar) was characterised using scanning electron microscopy before, and four weeks after, it was incorporated into each of four soils differing in clay content and organic matter. Scanning electron microscopy of Simcoa biochar after incubation in soil showed different degrees of attachment of soil particles to the biochar surfaces after 28 d. In addition, the effects of three biochars, Simcoa biochar, activated biochar and Wundowie biochar, on soil microbial biomass C and soil respiration were investigated in a short-term incubation experiment. It was hypothesised that all three biochars would have greater potential to increase soil microbial activity in the soil that had higher organic matter and clay. After 28-d incubation in soil, all three biochars had led to a higher microbial biomass C in the clayey soil, but prior to this time, less marked differences were observed in microbial biomass C among the four soils following biochar application.

关键词： clay amendment microbial biomass carbon scanning electron microscopy soil respiration

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