Mechanical and Morphological Properties of Highly Dispersed Carbon Nanotubes Reinforced Cement Based Materials

Stable homogeneous suspensions of multi-walled carbon nanotubes （MWCNTs） were prepared using gum arabic （GA） as dispersant and were incorporated to Portland cement paste. The dispersion was examined by ultraviolet visible spectroscopy （UV-vis）, and the concentration measurement shows that the optimum concentration of GA is 0.45 g · L^-1. The dispersibility of the surface-modified MWCNTs in aqueous solution and cement matrix were investigated by transmission electron microscopy （TEM） and energy dispersive spectroscopy （EDS）, and the mechanical properties of the composites were investigated. The results show that the addition of the treated nanotubes can improve both the flexural strength and the compressive strength of the Portland cement composite significantly. The flexural strength of the composite increases up to 43.38% with the MWCNT concentration of 0.08% （by weight of cement）. The porosity and pore size distribution of the composites were measured by mercury intrusion porosimetry （MIP）, and the results indicate that the cement paste doped with MWCNTs obtained lower porosity and concentrated pore size distribution. The morphological structure was analyzed by field emission scanning electron microscopy （FESEM） and EDS. It is shown that MWCNTs act as bridges and networks across cracks and voids, which transfer the load in case of tension, and the interface bond strength between the nanotubes and matrix is very strong.

Effect of Stewing in Cooking Step on Textural and Morphological Properties of Cooked Rice

Stewing of rice grains by steam after boiling in excess water can be used for cooking rice perfectly. The effects of this procedure in cooking of three varieties of Iranian rice （Sang Tarom, Domsiyah and Fair） on textural and morphological properties of cooked rice grains were investigated. The results showed that this step in rice cooking reduced the hardness and increased the adhesiveness of rice grains significantly. By the use of the scanning electron microscopy, it was shown that the outer surface of cooked rice stewed by steam had less porosity and closer pores due to the modification during cooking, and better gelatinization and more expansion of starch granules compared to non-stewed samples. The use of this procedure in rice cooking to provide a fully cooked and gelatinized, softer and stickier final product is recommended.

Morphological properties and proliferation analysis of olfactory ensheathing cells seeded onto three-dimensional collagen-heparan sulfate biological scaffolds

This study aimed to examine the differences in the morphological properties and proliferation of olfactory ensheathing cells in three-dimensional culture on collagen-heparan sulfate biological scaffolds and in two-dimensional culture on common flat culture plates. The proliferation rate of olfactory ensheathing cells in three-dimensional culture was higher than that in two-dimensional culture, as detected by an M-I-r assay. In addition, more than half of the olfactory ensheathing cells subcultured using the trypsinization method in three-dimensional culture displayed a spindly Schwann cell-like morphology with extremely long processes, while they showed a flat astrocyte-like morphology in two-dimensional culture. Moreover, spindle-shaped olfactory ensheathing cells tended to adopt an elongated bipolar morphology under both culture conditions. Experimental findings indicate that the morphological properties and proliferation of olfactory ensheathing cells in three-dimensional culture on collagen-heparan sulfate biological scaffolds are better than those in two-dimensional culture.

Morphological properties of medial amygdala-projecting retinal ganglion cells in the Mongolian gerbil

The amygdala is a limbic structure that is involved in many brain functions, including emotion, learning and memory. It has been reported that melanopsin-expressing retinal ganglion cells(ip RGCs) innervate the medial amygdala(Me A). However, whether conventional RGCs(c RGCs) project to the Me A remains unknown. The goal of this study was to determine if c RGCs project to the Me A and to determine the morphological properties of Me A-projecting RGCs(Me A-RGCs). Retrogradely labeled RGCs in whole-mount retinas were intracellularly injected to reveal their dendritic morphologies. Immunohistochemical staining was performed to selectively label ip RGCs(Me A-ip RGCs) and c RGCs(Me A-c RGCs). The results showed that 95.7% of the retrogradely labeled cells were c RGCs and that the rest were ip RGCs. Specifically, Me A-c RGCs consist of two morphological types. The majority of them exhibit small but dense dendritic fields and diffuse ramification patterns as previously reported in RG_(B2)(95%), while the rest exhibit small but sparse dendritic branching patterns resembling those of RG_(B3) cells(5%). Me Aip RGCs consist of M1 and M2 subtypes. The Me A-RGCs showed an even retinal distribution patterns. The soma and dendritic field sizes of the Me A-RGCs did not vary with eccentricity. In conclusion, the present results suggest that Me A-RGCs are structurally heterogeneous. These direct RGCs that input to the Me A could be important for regulating amygdala functions.

Effects of lead(Pb)-induced oxidative stress on morphological and physio-biochemical properties of rice

In rice,high concentration of lead(Pb)can cause phyto-toxicity affecting several physiological functions.Cultivation of rice varieties that are resistant to Pb-induced oxidative stress is an important management strategy in Pb-contaminated soils.In the current study,we evaluated four different rice cultivars for their response to Pb-induced stress.Three japonica type cultivars X-Jigna,Ediget,and Furat,and one Indica type cultivar Amber 33 were grown in soil containing different Pb concentrations(0 mM,0.6 mM,and 1.2 mM).The soil was treated with 0 mM or 0.6 mM or 1.2 mM Pb solution one month prior to rice seedling transplantation.Thereafter,four-week-old rice seedlings were transplanted into the treated soil and their responses were observed until maturity.The data revealed that a highest concentration of Pb(1.2 mM)induced significant reduction in agronomic traits such as plant height,number of tillers per plant,number of panicles per plant,and number of spikelets per panicle in all the rice cultivars.However,least reduction in the agronomic traits was observed in X-Jigna,whereas the highest reduction in the agronomic traits was observed in Ediget.Antioxidant activity of catalase(CAT),peroxidase(POD),polyphenol oxidase(PPO),and superoxide dismutase(SOD),was evaluated along with the accumulation of superoxide ions(O2.-),protein,proline,chlorophyll,sucrose,glucose,and fructose contents in all the rice cultivars.A significant increase in antioxidant activity and in the accumulation of proline and sucrose contents with the least reduction in the chlorophyll and protein contents was observed in X-Jigna suggesting that X-Jigna is the most tolerant among all the rice cultivars tested against Pb-stress.On the other hand,non-significant and slightly significant increase in the antioxidant activity,less accumulation of proline and sucrose contents,and higher reduction in the chlorophyll and protein contents was observed in Ediget,which further suggest that Ediget is the most susceptible rice cultivar to Pb-stress.In addition,the other rice cultivars Furat and Amber 33,were found to be moderately tolerant to Pb-induced oxidative stress.In summary,our results suggest that tolerance to Pb-induced oxidative stress would be a result of a synergetic action of both enzymatic and non-enzymatic antioxidant systems,leading to a balanced redox status in rice.

Copper Ion Beam Irradiation-Induced Effects on Structural,Morphological and Optical Properties of Tin Dioxide Nanowires

The 0.8 Me V copper （ Cu） ion beam irradiation-induced effects on structural, morphological and optical properties of tin dioxide nanowires （Sn02 NWs） are investigated. The samples are irradiated at three different doses 5 × 10^12 ions/cm2, 1 ×10^13 ions/cm2 and 5 × 10^13 ions/em2 at room temperature. The XRD analysis shows that the tetragonal phase of Sn02 NWs remains stable after Cu ion irradiation, but with increasing irradiation dose level the crystal size increases due to ion beam induced coalescence of NWs. The FTIR spectra of pristine Sn02 NWs exhibit the chemical composition of SnO2 while the Cn-O bond is also observed in the FTIR spectra after Cu ion beam irradiation. The presence of Cu impurity in SnO2 is further confirmed by calculating the stopping range of Cu ions by using TRM/SRIM code. Optical properties of SnO2 NWs are studied before and after Cu ion irradiation. Band gap analysis reveMs that the band gap of irradiated samples is found to decrease compared with the pristine sample. Therefore, ion beam irradiation is a promising technology for nanoengineering and band gap tailoring.

Structural,Morphological and Electrical Properties of In-Doped Zinc Oxide Nanostructure Thin Films Grown on p-Type Gallium Nitride by Simultaneous Radio-Frequency Direct-Current Magnetron Co-Sputtering

Zinc oxide （ZnO） is one of the most promising and frequently used semiconductor materials. In-doped nanos- tructure ZnO thin films are grown on p-type gallium nitride substrates by employing the simultaneous rf and dc magnetron co-sputtering technique. The effect of In-doping on structural, morphological and electrical properties is studied. The different dopant concentrations are accomplished by varying the direct current power of the In target while keeping the fixed radio frequency power of the ZnO target through the co-sputtering deposition technique by using argon as the sputtering gas at ambient temperature. The structural analysis confirms that all the grown thin films preferentially orientate along the c-axis with the wurtzite hexagonal crystal structure without having any kind of In oxide phases. The presenting Zn, 0 and In elements＇ chemical compositions are identified with EDX mapping analysis of the deposited thin films and the calculated M ratio has been found to decrease with the increasing In power. The surface topographies of the grown thin films are examined with the atomic force microscope technique. The obtained results reveal that the grown film roughness increases with the In power. The Hall measurements ascertain that all the grown films have n-type conductivity and also the other electrical parameters such as resistivity,mobility and carrier concentration are analyzed.

Preliminary Study on Tensile and Impact Properties of Kenaf/Bamboo Fiber Reinforced Epoxy Composites

The application of natural fibers as reinforcement in composite material has increased due to environmental concerns,low cost,degradability and health concerns.The purpose of this study is to identify the best type of bamboo fibers to be used as reinforcement for kenaf(K)/bamboo hybrid composite.There were three types of bamboo fibers evaluated in this study which include bamboo mat(B),bamboo fabric(BF)and bamboo powder(BP).Chemical composition of B,BF,BP and K fibers were analyzed in this study.The effect of different types of bamboo fibers on tensile,impact,and morphological properties were investigated.The B/epoxy composites displayed the highest tensile strength(53.03 MPa)while K/epoxy composite had the highest tensile modulus(4.71 GPa).Scanning electron micrographs of B/epoxy composites displayed better fiber/matrix interfacial bonding in comparison to other studied composites.Results showed that impact strength of BF-based composite was highest(45.70 J/m).In conclusion,the tensile strength of B/epoxy composite is superior to the other bamboo reinforced composites and will be further evaluated in the next study.

Morphological Characterization of Agave tequilana Weber Variety azul(Asparagaceae)under Cultivation in the Municipality of Llera,Tamaulipas,Mexico

The blue agave (Agave tequilana Weber variety azul) is a species that is widely used to produce tequila. For this reason, in the last decade, large extensions of terrain have been established for its cultivation. However, much of this land has been abandoned in a short time because at the beginning it was not known that at least six years were needed before the agave could be harvested. However, when the growers wanted to reintegrate some of these crops into the productive process, their exact age and the cultural activities needed for harvesting the agave were unknown because information regarding its vegetative development relative to its age was lacking. The hypothesis of this work was: If the morphological properties reflect the development state of the population individuals, then the properties height, basal area, rosette diameter, the north, south, east and west leaf, leaves number and foliar verticil will help to characterize the age categories in Agave tequilana Weber variety azul population under cultivated conditions. To this end, six plots with plants of different ages (one to six years) were selected in the municipality of Llera, Tamaulipas, Mexico. In each plot, 60 individuals were selected at random, and their morphological properties (height, basal area, rosette diameter, northern leaf, southern leaf, eastern leaf, western leaf;number of leaves and leaf whorl) were measured. With these data, a principal component analysis was performed to determine which of these properties explains the most variation of the data. The results indicate that height and basal area are the properties that are most closely associated with plant age. It is also for the first time demonstrated that harvest time can be reduced by one or two years, which favors producers economically because it could generate savings in production costs.

Properties,Microstructures and Precipitate Morphology of Hot-rolled Interstital-Free(IF)Steel Sheets

In order to simplify production process and to decrease production cost of thicker cold-rolled iF steel sheets for deep drawing applications, a new hot-rolled IF steel sheet is developed through hot-rolling in or region. In this paper, properties, microstructures and precipitate morphology of hot-rolled iF steel sheets are described..

Physical Properties of Crushed Air-cooled Blast Furnace Slag and Numerical Representation of Its Morphology Characteristics

Physical properties and geometrical morphologies of crushed air-cooled blast furnace slag （SCR） and crushed limestone （LCR） were comparatively investigated. The shape, angularity, surface texture and internal pore structure of aggregate particles for different size and gradation were numerically represented by sphericity （ψ） and shape index （SI）, angularity number （AN）, index of aggregate particle shape and texture （IAPST）, porosity and pore size, respectively. The results show that SCR is a porous and rough aggregate. Apparent density, void, water absorption and smashing index of SCR are obviously higher than those of LCR with the same gradation, respectively. However, bulk density of SCR is lower than that of LCR with the same gradation. SI, AN, IAPST and porosity of SCR are obviously higher than those of LCR with the same gradation, respectively. The smaller particle size of SCR, the larger of its AN, IAPST and porosity.

Effect of In_xGa_(1-x)As Interlayer on Surface Morphology and Optical Properties of GaSb/InGaAs Type-Ⅱ Quantum Dots Grown on InP (100) Substrates

The effects of indium composition in InGaAs interlayer and on optical properties of GaSb/InGaAs QD material on morphology of GaSb/InGaAs quantum dots （QDs） system are studied. AFM images show that the change of the indium composition in InGaAs interlayer can alter the GaSb QD morphology. It is found that low indium composition in InGaAs interlayer can promote the formation of QDs, while high indium composition can inhibit the formation of QDs. The photoluminescence （PL） spectra of GaSb/InGaAs QDs at 8 K under low excitation power indicate that the third root of the excitation power is linear with the peak position, which provides a direct evidence for their luminescence belonging to type-Ⅱ material optical transition. The PL spectra at 8 K under an excitation power of 90row show that the optical properties of GaSb/InGaAs QD material system can be affected by the indium composition in the InGaAs interlayer, and the PL peak position is linear with the indium composition. The optical properties of GaSb/InGaAs QDs can be improved by adjusting the indium composition in the InGaAs interlayer.

An overview of biomass solid fuels:Biomass sources,processing methods,and morphological and microstructural properties

Biomass solid fuel(BSF)has emerged as a promising renewable energy source,but its morphological and microstructural properties are crucial in determining their physical,mechanical,and chemical characteristics.This paper provides an overview of recent research on BSF.The focus is on biomass sources,BSF processing methods,and morphological and microstructural properties,with a special emphasis on energy-related studies.Specific inclusion and exclusion criteria were established for the study to ensure relevance.The inclusion criteria encompassed studies about BSFs and studies investigating the influence of biomass sources and processing methods on the morphological and microstructural properties of solid fuels within the past five years.Various technologies for converting biomass into usable energy were discussed,including gasification,torrefaction,carbonization,hydrothermal carbonization(HTC),and pyrolysis.Each has advantages and disadvantages in energy performance,techno-economics,and climate impact.Gasification is efficient but requires high investment.Pyrolysis produces bio-oil,char,and gases based on feedstock availability.Carbonization generates low-cost biochar for solid fuels and carbon sequestration applications.Torrefaction increases energy density for co-firing with coal.HTC processes wet biomass efficiently with lower energy input.Thermal treatment affects BSF durability and strength,often leading to less durability due to voids and gaps between particles.Hydrothermal carbonization alters surface morphology,creating cavities,pores,and distinctive shapes.Slow pyrolysis generates biochar with better morphological properties,while fast pyrolysis yields biochar with lower porosity and surface area.Wood constitutes 67%of the biomass sources utilized for bioenergy generation,followed by wood residues(5%),agro-residues(4%),municipal solid wastes(3%),energy crops(3%),livestock wastes(3%),and forest residues(1%).Each source has advantages and drawbacks,such as availability,cost,environmental impact,and suitability for specific regions and energy requirements.This review is valuable for energy professionals,researchers,and policymakers interested in biomass solid fuel.

Design and criteria of electrospun fibrous scaffolds for the treatment of spinal cord injury

The complex pathophysiology of spinal cord injury may explain the current lack of an effective therapeutic approach for the regeneration of damaged neuronal cells and the recovery of motor functions. Many efforts have been performed to design and develop suitable scaffolds for spinal cord regeneration, keeping in mind that the reconstruction of a pro-regenerative environment is the key challenge for an effective neurogenesis. The aim of this review is to outline the main features of an ideal scaffold, based on biomaterials, produced by the electrospinning technique and intended for the spinal cord regeneration. An overview of the poly- mers more investigated in the production of neural fibrous scaffolds is also provided.

Collapse behavior and microstructural evolution of loess soils from the Loess Plateau of China

Loess soils are characterized by metastable microstructure, high porosity and water-sensitivity. These soils have always been problematic soils and attracted attention from researchers all over the world. In the present study, three loess soils extracted at various depths from the Loess Plateau of China, i.e. Malan(Q_3), upper Lishi(Q_2~2) and lower Lishi(Q_2~1) loess soils, were studied. Single oedometer-collapse tests were performed on intact loess specimens to investigate the collapse behavior of three loess soils. The microstructure and chemical composition of each loess before and after collapse test were characterized using scanning electron microscopy(i.e. SEM) and energy dispersive spectroscopy(i.e. EDS) techniques. The microstructural evolution due to wetting collapse was interpreted qualitatively and quantitatively in terms of the pore morphology properties. The results suggest that:(1) the collapse potential of each loess may rise again after a round of rise and drop, which could be failure of the new-developed stable structure under quite high vertical pressure. It implies that loess may collapse even if it has collapsed.(2) Q_3, Q_2~2 and Q_2~1 loess have different types of microstructure, namely, granule, aggregate and matrix type of microstructure, respectively.(3) The microstructural evolution due to loading and wetting is observed from a granule type to an aggregate type and finally to a matrix type of structure. The variations in distributions of pore morphology properties indicate that collapse leads to a transformation of large-sized pores into small-sized pores, re-orientation and remolding of soil pores due to particle rearrangement.(4) A porous structure is essential for loess collapse; however, the non-water-stability of bonding agents promotes the occurrence of collapse under the coupling effect of loading and wetting.

RECENT DEVELOPMENTS IN PHOTOINITIATED CROSSLINKING OF POLYETHYLENE AND ITS INDUSTRIAL APPLICATIONS

The recent developments in the photoinitiated cross-linking of polyethylene and the significant breakthrough of its industrial application are reviewed. The enhanced photo-initiation system, the dynamics of photoinitiated crosslinking, the optimum conditions, the crystal morphological structures and related properties, and the photo- and thermo-oxidation stability of photocrosslinked polyethylene (XLPE) materials have been elucidated systematically. A new technique for producing photocrosslinked XLPE-insulated wire and cable is described in detail. It can be expected that the future applications of photocrosslinking technique of polyolefins will be very promising.

Preparation and Characterization of Urea-formaldehyde Resin/reactive Montmorillonite Composites

The urea-formaldehyde resin/reactive montmorillonite composites were prepared by in situ polymerization. The reactive montmorillonite was prepared firstly by being ion exchanged with organic molecules and secondly by being grafted with silane coupling agent, which could be demonstrated by X-ray diffraction（XRD） and thermogravimetric analysis（TGA）. Scanning electron microscopy（SEM） revealed that the morphology of the urea-formaldehyde resin/reactive montmorillonite composites were ellipsoid or columnar particles. Energy dispersive spectrometry（EDS） confirmed that the reactive montmorillonite was encapsulated by urea-formaldehyde resin. Differential scanning calorimetry（DSC） indicated that curing process of the ureaformaldehyde resin/reactive montmorillonite composites consumed more energy than pure urea-formaldehyde resin. Thermogravimetric analysis（TGA） showed that the thermal stability of the urea-formaldehyde resin/reactive montmorillonite composites improved compared to pure urea-formaldehyde resin. Furthermore, the reactive montmorillonites reduced the formaldehyde emission of the composites and increased the water resistance. Finally, the mechanism to prepare the urea-formaldehyde resin/reactive montmorillonite composites was proposed.

Influence of Calcination on the Physical Characteristics and Nitrogen Removal Performance of Clinoptilolites

The influences of roasting activation on the particle morphology, microscopic structure, and adsorption properties of natural clinoptilolites were investigated. The experimental results show that the optimal modified conditions include a calcination temperature at 400 ℃, a roasting time of 0.5 h, and furnace cooling. The ammonia nitrogen removal rate from analog renewable water of the modified clinoptilolites reached 72% in the optimized conditions, which is 12% higher than that of natural ones. Scanning electron microscopy analysis showed that the surface morphology changed, the micro-hole size increased, and the surface became smoother and more uniform after calcination. The single-point total adsorption average pore width increased from 7.74 nm to 10.64 nm.

Preparation and Characterization of Multi Shape ZnO/PVDF Composite Materials

Two different morphologies of ZnO（lotus-shaped, rod-shaped） and ZnO/PVDF composite materials were prepared. The morphologies of ZnO and composite materials were characterized by scanning electron microscopy（SEM） and transmission electron microscopy（TEM）. Fourier transform infrared spectroscopy（FT-IR）, thermal gravimetry（TG）, and X-ray diffraction（XRD） were also used to characterize the chemical structures and phase composites of ZnO and ZnO/PVDF composite materials. Breakdown voltage, dielectric constant and dielectric loss of ZnO/PVDF composite materials were also tested. Microstructure analysis showed that ZnO nanoparticles dispersed uniformly in the matrix. And the dielectric constant expresses a significantly improvement while the dielectric loss and breakdown voltage expresses no significant change. Moreover, dielectric constant keeps an improvement tendency with increasing content of ZnO.

INVESTIGATION INTO MORPHOLOGY, MICROSTRUCTURE AND PROPERTIES OF SBR/EPDM/ORGANO MONTMORILLONITE NANOCOMPOSITES

Rubber compounds based on styrene-butadiene rubber/ethylene propylene diene monomer blends of different compositions （60/40, 70/30, 80/20, 90/10, 100/0） reinforced with 1 wt%, 3 wt%, 5 wt% and 7 wt% organoclay （Cloisite 20A） were prepared on a two roll mill via a vulcanization process and characterized by several techniques. Results of X-ray diffraction showed expansion of the inter-gallery distance, and transmission electron microscopy （TEM） micrographs confirmed that the prepared nanocomposite samples have intercalated and partially exfoliated structures. Cure characteristics showed that, organoclay not only accelerates the vulcanization reaction, but also gives rise to a marked increase of the torque, indicating crosslink density of the prepared compounds increases at the presence of organoclay. Mechanical properties of samples received markedly increase by clay loading due to the good interaction established between nanoclay particles and polymer matrix as it was evidenced by SEM photomicrographs. At the same time, rheological properties showed that addition of nanoclay could improve storage modulus as well as complex viscosity of SBR/EPDM samples. The results of ozone test revealed that the ozone resistance of samples significantly increases as nanoclay or EPDM content increases.