Friable Structure Research Articles

Template-Assisted SnO2: Synthesis, Composition, and Photoelectrocatalytical Properties

A series of tin oxides were synthesized with polystyrene microspheres (250 nm) as the template. It was shown that an increase in the template content led to increasing specific pore volume and to the formation of bimodal pore structure with pores of 9 and 70 nm in diameter. Addition of cetyltrimethylammonium bromide (CTAB) during synthesis led to the formation of friable structures (SEM data), to an increase in the average pore diameter from 19 to 111 nm, and to the formation of macropores of 80–400 nm in size. All materials had similar surface properties and cassiterite structure with 5.9–10.8 nm coherent scattering region (XRD data). Flat-band potentials of the samples were determined and their photoelectrocatalytic properties to oxidation of water and methanol were studied in the potential range of 0.4–1.6 V RHE. It was shown that the sample obtained using CTAB was characterized by lower flat-band potential value, but appeared significantly higher photocurrent in methanol oxidation, which resulted from enhanced macro-meso-porous structure to facilitate methanol pore diffusion.

The effect of 2,4-D, BA and Thidiazuron on somatic embryo induction of liberica coffee of Tungkal Composite from Jambi

The Tungkal Composite of liberica coffee rejuvenation program at Jambi Province is urgently needed due to the latest status of the plants are old and showing diseased attacked. To support the rejuvenation, the provision of seedlings could be done by tissue culture approach through somatic embryogenesis. This research aimed to study the effect of 2,4-D, BA and TDZ on callus formation and embryo induction from liberica coffee leaf explants. Explants used were leaf sections with or without veins. Explants were grown on Murashige Skoog (MS) basal medium with 2,4-D + BA and 2,4-D + TDZ. A completely randomized design was employed in the trial, and each experimental unit was replicated three times. Results showed that callus could be formed on both types of explants, but leaf explants with veins could produce callus faster. The use of BA in medium could induce callus formation faster than TDZ. The higher the concentration of 2,4-D, BA and TDZ, the slower callus initiation. The addition of TDZ in the medium resulted in mostly callus, while callus from medium with BA showed a friable structure. Globular somatic embryos were formed in all treatments with varying amounts. TDZ can induce more globular somatic embryo than BA.

DETERMINATION OF SOME NUTRITIONAL COMPONENTS AND SENSORY CRITERIA OF IGNAME YAM IN BAC GIANG PROVINCE (Dioscorea esculenta)

Igname yams are agricultural products with high economic and nutritional value. Igname yam plants are grown a lot in our country, especially in Bac Giang province. The aim of this study was to the determination of nutritional components and sensory of igname yam in Bac Giang province. Research results have identified water content in igname yam is 69.3 ± 0.2%, total lipid content is 4.2 ± 0.1%, total glucide content is 20.5 ± 0.1%, total protein content was 2.6 ± 0.1%, vitamin B1 was 28.5 ± 0.1mg% and vitamin B2 was 12.3 ± 0.1mg%. Besides, the content of minerals, such as Ca, Mg, Mn, P, K, Na, Zn, Cu, S, and Fe, fluctuates in the range of 1.4 to 34mg%. By the HPLC method, 17 amino acids have been identified in igname yam. Among those, there were 9 non-substituting amino acids, including histidine, arginine, threonine, valine, methionine, lysine, isoleucine, leucine, and phenylalanine. The igname yam meat has an ivory white color, a characteristic aroma, a fatty taste, a spongy and friable structure. These are important scientific bases for selecting igname yam for processing food products.

Effect of 2,4-D and BAP on Morphological Characters and Genetic Stability of Kaffir Lime (Citrus hystrix DC.) Callus Cultures Among Generations

Kaffir lime has medicinal properties for the treatment of many diseases. We used in vitro culture techniques to maintain quality and increase the production of active compounds in kaffir lime. The objective of this study is to determine the phenotype and genotype of kaffir lime callus cultures grown on media with the addition of 2,4-Dichlorophenoxyacetic (2,4-D) and Benzylaminopurine (BAP) on three generations (G0, G1, and G2). The callus was induced and subcultured on Murashige and Skoog medium added with 2,4-D: BAP at concentrations of 1:0.5; 2:0 and 5:0. Results showed no significant difference in callus initiation time in all treatment groups. Morphological characteristics, including color, texture, and biomass, varied among growth regulator concentrations and generation level. A high level of callus generation corresponds to a more friable texture and a more yellowish callus. Callus grown with the addition of 2,4-D and BAP 2:0 and 5:0 showed a more friable structure and yellowish color than 1:0.5. Growth regulator concentrations in each generation did not affect the callus growth curves, but the length of each phase between generations was different. The exponential phases of G1 and G2 were faster than that of G0. Despite slight differences in phenotype, the DNA profiles of callus suggest the same pattern between treatment groups, thereby indicating that our kaffir lime callus has genetic stability and that the callus can be used as raw material for medicinal purposes. Keywords: ISSR markers, Kaffir lime callus, Generations, Genotype, Growth factor, Phenotype

Callus Induction from Cotyledon of Gyrinops versteegii (Gilg.) Domke

Gyrinops versteegii is an endemic plant in eastern Indonesia that produced agarwood with high quality and economic value. This plant has been threatened by overexploitation which leads on decreasing in the natural population. This research aimed to induce in vitro callus formation to support the sustainable utilization of G. versteegii, which in the end, may support plant productivity. Callus induction was investigated using cotyledon and cultured on MS medium supplemented with several combination of plant growth regulators. The observations were done for the number of explants turned into callus and the duration for the first callus formation. The results showed that combination of 3 mg/L NAA + 0.5 mg/L BAP was recorded as the best combination for callus induction (63.63%). Callus with friable structure and bright color are obtained within nine days of incubation and showed the characteristic of embryonic callus. This result is expected to give a significant opportunity to conserve the natural population of G. versteegii.

Multiplication of arabica “Solok Rajo” coffee through bio cellular technology

The extensification of Rajo coffee cultivation faces obstacles due to the limited quality of planting material. Biocellular technology can be used for the mass propagation of plants in a short time. The objective of this study was to develop an effective in vitro protocol for propagating Rajo coffee. The media used for in vitro coffee seed germination was MS media strength [0; ¼; ½; ¾; 1 MS [full]]. Subsequently, the explant was transferred to full MS media supplemented with BAP [0,0; 2,5; 5,0; 7,5; 10,0 mg l−1]. Callus induced from young leaves cultured on MS medium supplemented with 2,4-D [2,0; 3,0; 4,0 mg l−1] and BAP [0.0; 0.5; 1.0; 1.5 mg l−1]. From the initial experimental results obtained that seeds can be considered a good starting material for in vitro establishment in the propagation of Arabica coffee “Solok Rajo”. The ¼ MS medium gave more root, hypocotyls, and plantlet length, and full cotyledonary leaves expansion. The addition of 5.0 and 7.5 mg l−1 BAP was able to increase the number of shoots and shoot length. BAP and 2,4-D affected callus initiation and development of Rajo coffee explants, where all concentrations could induce callus, but 3,0 mg l−1 2,4-D was able to induce callus better and faster. There was no interaction between 2,4-D and BAP for callus induction and there was no effect between the addition of 2 mg l−1, 3 mg l−1, and 4 mg l−1 on callus induction. The addition of BAP affected the callus induction time and callus fresh weight. In general, callus formed has a friable structure with yellowish-white color.

Effects of Non-covalent Functionalization and Initial Mixing Methods on SWNT/PP and SWNT/EVOH Composites.

We report that a simple, low-cost type of spray-freeze drying (SFD) significantly improves the dispersion of single-walled carbon nanotubes (SWNTs) in thermoplastic polymers. Conventional SFD requires costly specialized equipment and large amounts of material, both of which are impediments to laboratory research on nanomaterial composites. Our method uses more readily available equipment and can be adapted to use milligrams to grams of material. A household spray bottle containing an aqueous nanomaterial dispersion is used to spray the dispersion into a dish of liquid nitrogen. The resulting material is then lyophilized in a standard laboratory freeze dryer. The usefulness of this simplified method was explored by comparing the properties of polypropylene (PP) composites produced by this method to those produced by a previously reported rotary evaporation method in which the dispersion is vacuum-dried onto the polymer. The role of the initial dispersion state was explored by using pristine SWNTs as well as SWNTs stabilized by two common SWNT stabilizers: polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate. Based on rheological, thermal, and morphological characterization, the porous friable structures produced by SFD resulted in better SWNT dispersion compared to composites produced by a previously reported rotary evaporation method. However, the PP/PVP-SWNT nanocomposites produced by both methods contained large aggregates. To verify that this aggregation behavior was the result of thermodynamic incompatibility between PP and PVP, ethylene vinyl alcohol (EVOH) nanocomposites containing PVP-SWNT were also produced using the SFD method. The results of this research show how a low-cost alternative to SFD along with careful consideration of compatibility is a promising approach to produce nanocomposites.

The evaluation of java fine flavor cocoa propagation through somatic embryogenesis technique for germplasm preservation

Somatic embryogenesis is one of the newest technology that applied for the mass production of cocoa. This research aims to evaluate the regeneration rate of somatic embryos through somatic embryogenesis propagation techniques on java fine flavor cocoa. Cultivars in this study are ICCRI 01, ICCRI 02, DR 1, DR 2, DRC 16, DR 38, PNT 16, and PNT 30. Observations include parameters to determine the percentage of primary callus and embryogenic callus formation and the number of somatic embryos produced. Based on data, the ability of callus to produce primary embryos is highly dependent on plant cultivars and explant sources. Five cultivars showed a higher regeneration rate using explants from the petal part, while the rest showed a higher regeneration rate using explants from the staminode section. Embryogenic callus from each cacao cultivar has the same basic structure: a nodular friable structure consisting of many embryonic cells. Some fine flavor cacao cultivars that were able to produce callus and primary somatic embryos could not produce secondary somatic embryos and plantlets. However, two cultivars, which had low potential in producing primary embryos, had the high ability to produce secondary somatic embryos and develop into plantlets.

РОЛЬ ЖЕЛЕЗО СОДЕРЖАЩЕГО КОМПОНЕНТА В СОСТАВЕ ПЕРЛИТОВОГО ГЕОПОЛИМЕРА НА ЕГО ФАЗОВЫЕ И СТРУКТУРНЫЕ ТРАНСФОРМАЦИИ

Normally, the component composition of building materials makes a significant contribution when formation of final performance properties of them. Moreover, new types of binding systems, in spite of their poor knowledge, this effect on the structural characteristics of final composites also takes place. In this work, perlite-based geopolymer binder as an example, was studied.
 In framework of the study, it was found that the application of grinding mill with a metal lining leads to the formation of Fe- milling yield, which is included into crushed raw materials (perlite) com-position.
 It was established that the particles of the resulting Fe- component are nanoscaled.
 The X-ray phase and chemical analyzes were used to determine the mechanism of the effect of the Fe- component on the properties of perlite-based geopolymer. 
 Microstructure of the hardened geopolymer paste were studied using SEM microscopy. Phase and mineral composition of geopolymer paste obtained by XRD-analysis showed, when the hardening process, nanosized iron hydroxide or bernalite Fe(OH)3(H2O)0.25 is formed in the geopolymer system, that is 5 times more than metallic iron. This is initiates the structure destruction and confirmed by the low values compressive strength of the geopolymer stone.
 Keywords: Fe-bearing component, metallic milling yield, geopolymer binder, friable structure, the Scherrer formula

Comparison of Conventional and Pontic Fixed Partial Dentures Over Implants Using the Finite Element Method: Three-Dimensional Analysis of Cortical and Medullary Bone Stress.

Rehabilitation with implant prostheses in posterior areas requires the maximum number of possible implants due to the greater masticatory load of the region. However, the necessary minimum requirements are not always present in full. This project analyzed the minimum principal stresses (TMiP, representative of the compressive stress) to the friable structures, specifically the vestibular face of the cortical bone and the vestibular and internal/lingual face of the medullary bone. The experimental groups were as follows: the regular splinted group (GR), with a conventional infrastructure on 3 regular-length Morse taper implants (4 × 11 mm); and the regular pontic group (GP), with a pontic infrastructure on 2 regular-length Morse taper implants (4 × 11 mm). The results showed that the TMiP of the cortical and medullary bones were greater for the GP in regions surrounding the implants (especially in the cervical and apical areas of the same region) but they did not reach bone damage levels, at least under the loads applied in this study. It was concluded that greater stress observed in the GP demonstrates greater fragility with this modality of rehabilitation; this should draw the professional's attention to possible biomechanical implications. Whenever possible, professionals should give preference to use of a greater number of implants in the rehabilitation system, with a focus on preserving the supporting tissue with the generation of less intense stresses.

Clay mineralogical and geochemical evidences of lateritic weathering at about 2.2 ga prior to the evolution of life on earth

This study incorporates a well-developed lateritic profile occurring within the Aravalli Supergroup sediments of 2200 Ma-1850 Ma age from Rajasthan, Western India. The lateritic paleosol exposed in a 60 m query was studied for field characteristics, clay mineralogy, and geochemical features to assess weathering and paleoclimatic conditions during Precambrian. The paleosol is marked by intense weathering with deep-red and light orange colours, massive to friable blocky structure, which progressively grades down to unaltered dolomite in the lower most part. The X-ray diffraction studies of the total clay (<2 μm) and the fine clay (<0.2 μm) fractions of the lateritic paleosols are characterized by 7A°, 3.58 A°, 3.52 A°, and 3.03A° mineral assemblage dominated by the kaolinite and anatase in large amounts. Other clay minerals include halloysite, mixed layers of kaolinite-halloysite, and calcite-veterite in small proportions. The energy dispersive X-Ray spectrometry (EDS) analysis of a few concretions show large scale enrichment of Al, Fe and Ti and the losses of the Ca, Mg, Na, and K during weathering and formation of the clay minerals. These features provide the evidence of intense weathering conditions under hot-humid climate leading to the formation of laterite prior to evolution of life on Earth at about 2.2 Ga.

Regeneration Rate of Eggplant Somatic Embryogenic In Various Maturation Media

Ralstonia solanacearum is one of the most important pathogen that causes bacterial wilt disease in eggplant and inhibits eggplant production. Improvement of eggplant varieties resistant to bacterial wilt can be accomplished through genetic manipulation. Regeneration of in vitro plants isone of the important tools to supports plant improvementthrough biotechnology. This study was aimed to determine the rate of eggplant regeneration in various maturation media, and to find the best medium for eggplant regeneration based on maturation rate and the number of cotyledon produced. We used resistant eggplant (accession 032) as the material to produce somatic embryogenic.There were 7 types of regeneration media used in this research. MS medium was supplemented with a certain concentration of plant growt regulators , such as: 1 mg / L + BAP 1 mg / L, NAA 4mg / L, TDZ 0.005 mg / L, TDZ 0.001 mg / L, CuSO4 2mM + BAP 1 mg / L, CuSO4 2mM + BAP 2 mg / L and Kinetin 1 mg / L + CuSO4 2mM. Three clumps of callus per plate with three replications were transferred to MS suplemented medium. The parameters observed were the color of callus before and after they were transfered to regeneration medium, the day of formation of globular, heart-shaped, tubular and cotyledonary phase, and the number of cotyledons formed. The results obtained showed the somatic embryogenic color of the 032 genotype was white with friable structure before being transferred to regeneration medium and was turned to yellowish white after being transferred to the regeneration medium. On the day sixth, friable embryogenic somatic of eggplant was developed into nodule on medium MS + NAA 4 mg / L, MS + CuSO4 2mM + BAP medium 1 mg / L, and MS + CuSO4 2mM + BAP 2 mg / L. Somatic embryogenic callus of accession 032 were able to pass complete globular, heart-shaped, tubular and cotyledonary phase. The most responsive medium for somatic embryogenic callus regeneration, based on the days of the callus phases formation and the number of early-phase cotyledons obtained, were MS medium suplemented with CuSO4 2mM + BAP,and CuSO4 2 mM + BAP 2 mg / L.Keywords: eggplant, Ralstonia solanacearum, regeneration, cotyledonary, clump, BAP

Structural and compositional changes in eucalyptus wood chips subjected to dry torrefaction

The aim of this study was to evaluate the structural and compositional changes in eucalyptus wood chips subjected to dry torrefaction. The experiment was conducted in a semi-continuous screw reactor with indirect heating system. Wood chips samples of three initial moisture contents (0, 15 and 30% dry basis) were torrefied up to three final temperatures (220, 260 and 300°C) and at three heating times (10, 15 and 20min). The effect of these variables was evaluated through the analysis of chemical composition, thermogravimetry and mechanical durability of the torrefied wood chips. The increase at temperature and time of torrefaction, as well as the drop in the initial moisture content, promoted significant structural and compositional changes in the wood chips. The torrefied samples present a higher resistance to thermal degradation, more friable structure, higher lignin and lower polysaccharides contents than the untreated samples. These changes made it possible to increase the quality of the eucalyptus wood chips to be use as a solid fuel.

Indirect somatic embryogenesis on rare octoploid Asparagus breslerianus plants

Abstract Asparagus breslerianus Schultes & Schultes fil is considered a rare wild octoploid species, which needs preservation against livestock grazing and erosion. In vitro method, especially somatic embryogenesis, is a useful method to perform mass micropropagation of identical clones. In the present study, spear buds of Asparagus breslerianus were used to obtain in vitro somatic embryos and, subsequently turn them into plantlets. Calli were developed on callus induction media (MS + 0.88 μM BA + 1.07 μM NAA). Then, they were transferred for four weeks to somatic embryogenesis induction phase media with different concentrations of 2,4-D (0, 4.53, 9.05 and 13.57 μM) and BA (0, 4.44, 8.88 and 13.32 μM). 2,4-D and BA were eliminated from induced calli media in realization phase. As a result globular, bipolar and mature embryos were observed six weeks later. Calli with compact or friable structures either green or yellowish produced embryogenic calli. Once the mature embryos developed shoots, they were transferred to root initiated media consisting of MS +3.9 μM Ancymidol and 1.07 μM NAA. Two months later, storage roots were produced on in vitro well-regenerated plantlets. The survival of asparagus plantlets in the acclimation phase was improved by the development of storage roots.

THE INFLUENCE OF GENOTYPICAL AND PARATYPICAL FACTORS ON THE INCIDENCE OF LIMB IN COWS OF UKRAINIAN BLACK-AND-WHITE DAIRY BREED

Introduction. In the world there is widespread lameness in the dairy cattle herds. More than at 90% cases lameness is conditioned by affections in area of a hoof. The affections of extremities at cattle inflict considerable economic losses through the decline of the dairy productivity, reproductive function, loss of pedigree value, protracted treatment and premature culling. Principal reason of illness is violation in feeding and keeping of cows, thus they not always are related to the failure to observe of norms of feeding; it is necessarily needed to take into account comprehensibility of nutrients of feed, productivity of cows and genetic inclination them to the diseases. At the same time it follows to take into account the inherited factor, especially in relation to the form of hoofs, quality of hoof horn and others. It is set that a form of hoofs is a trait which is well inherited. To the preventive factors belong breeding measures, foremost. In Ukraine Holstein population increases annually, part of heredity of Holstein breed grows in the herds of domestic dairy breeds. The high-producing cows of Holstein Friesian breed have a genetic predisposition to chronic and subclinical laminitis of extremities, that conditioned by the friable structure of hoof horn, structure of back legs, by the size of angle between soil and dorsal wall of hoofs and weakness of copulas. Taking into account it the actual is a study of problem of morbidity of extremities and evaluation of the state of hoofs for cows. The aim of our researches was study of influence of genotypical factors on morbidity of extremities in Ukrainian Black-and-White Dairy cows. Materials and methods of researches. Researches of the state of extremities in cows were conducted in the herd of "Osrikiyvske" farm (Kyiv region) at Ukrainian Black-and-White dairy breed. The statistical processing of data and analysis of variance were conducted by М. A. Plokhinskiy method (1969) using STATISTICA 6.0 software. Elements of ethological researches and materials of veterinary records at the farm were used for identifying cows with the diseases of extremities. Amount of the cows taken into account is 470 head. Results of researches. According to State breeding register in 2015 the average dairy productivity of cows of the herd at "Osrikiyvske" farm was 7731 kg of milk per year. The dairy productivity of first-calf heifers was over 6000 kg of milk, the level of milk yield during the third lactation increased by 16%. Observation of the animals in the herd during milking, consumption of feed and movement showed that 9.4% of cows had traits of lameness, 45% of them were first-calf heifers. Average milk yield of healthy cows (6756 ± 133.0kg) was significant (Р &lt; 0.05) and higher, than in limping cows (5654 ± 329.0 kg). It follows, that at comparison of healthy first-calf heifers and those which limped, this difference was greater (7001 ± 145 against 5391 ± 305 kg accordingly, Р &lt; 0.05). In both cases the difference is significant. Considerable divergences of frequency of limping cows were found in progeny of different bulls. Frequency of cows with sick extremities in progeny of bulls D.Lobbi 16210, L.Kingli 9948, G.Tandem 34213 was within the limits of 7%. Mostly sick extremities were in daughters of bulls Vasari 18899, A.Audini 55912 – 20 and 13.3%, accordingly. Circumstance that the level of morbidity of extremities for daughters of different bulls is different, can testify to influence of father on this trait. However, by results of the analysis of variance it was not found significant influence of genotypical factors on morbidity of extremities at Ukrainian Black-and-White dairy cows. So, force of father's and line influence on the investigated trait was – 0.22 ± 0.31 (P &gt; 0.05) and 0.043 ± 0.04 (P &gt; 0.05), accordingly. Also it was not revealed significant influence of sequence number of lactation on morbidity (η2x = 0.012 ± 0.01 (P &gt; 0.05)). But significant influence of level of the dairy productivity (milk yield, kg) on health of extremities (η2x = 0.018 ± 0.03 (P &lt; 0.01) was found. Conclusions. 9.4% of limping cows were found in the herd of "Osrikiyvske" farm. Reliable influence (1.8%) of dairy productivity on health of extremities was revealed. It was not educed significant influence of factors "father", "line", "sequence number of lactation" on the investigated trait. Thus, selecting animals for the increase in dairy productivity, it is necessary to search ways and methods for increasing durability of hoof horn for the sake of increase in productive use duration of cows.

Macro- and microscopic properties of strontium doped indium oxide

Solid state synthesis and physical mechanisms of electrical conductivity variation in polycrystalline, strontium doped indium oxide In2O3:(SrO)x were investigated for materials with different doping levels at different temperatures (T = 20–300 °C) and ambient atmosphere content including humidity and low pressure. Gas sensing ability of these compounds as well as the sample resistance appeared to increase by 4 and 8 orders of the magnitude, respectively, with the doping level increase from zero up to x = 10%. The conductance variation due to doping is explained by two mechanisms: acceptor-like electrical activity of Sr as a point defect and appearance of an additional phase of SrIn2O4. An unusual property of high level (x = 10%) doped samples is a possibility of extraordinarily large and fast oxygen exchange with ambient atmosphere at not very high temperatures (100–200 °C). This peculiarity is explained by friable structure of crystallite surface. Friable structure provides relatively fast transition of samples from high to low resistive state at the expense of high conductance of the near surface layer of the grains. Microscopic study of the electro-diffusion process at the surface of oxygen deficient samples allowed estimation of the diffusion coefficient of oxygen vacancies in the friable surface layer at room temperature as 3 × 10−13 cm2/s, which is by one order of the magnitude smaller than that known for amorphous indium oxide films.

Early transformation and transfer processes in a Technosol developing on iron industry deposits

SummaryLarge surface areas covered with man‐made materials are subject to pedogenetic evolution. However, pedogenetic processes in the resulting Technosols are seldom fully assessed. This work was conducted to identify and characterize the processes occurring on deposits of industrial technogenic materials. A former settling pond of the iron and steel industry where a forest has established since termination of the industrial activity approximately 50 years ago was chosen. A 2‐m deep pit was opened, and a series of layers of the soil profile were sampled. The macro‐ and micro‐structure were studied, and soil samples were analysed for structural, chemical and mineralogical assessment (chemical analyses, X‐ray diffraction, infrared and Mössbauer spectroscopies, scanning and transmission electron microscopies coupled with energy dispersion spectrometry). Results showed that the profile was composed of a succession of sub‐horizontal layers arranged in two groups according to their structure and composition, linked to the composition of the industrial effluent. Group 1 was composed of iron‐, carbonate‐ and aluminosilicate‐rich layers exhibiting a compact structure. Group 2 contained manganese‐rich layers with a friable structure. Pedogenetic processes of various intensities were detected at different depths. Besides an accumulation of organic matter at the surface, transformations of minerals were recorded all along the soil profile, with weathering, leaching and precipitation of new phases. Phenomena occurred primarily in specific zones, such as cracks and interfaces between two layers. In conclusion, the soil maintained characteristics of the original industrial material and displayed several stages of pedogenesis, which were controlled chronologically by climatic and biological factors.

New Reduced Graphene Oxide/Alumina (RGO/Al2O3) Nanocomposite: Innovative Method of Synthesis and Characterization

A novel method was developed to synthesize reduced graphene oxide/alumina nanocomposite (RGO/Al2O3) by in situ depositing Al2O3 nanoparticles on graphene oxide flakes by a dry sol–gel process. The scanning electron microscopy and energy dispersive X‐ray spectroscopy investigations results showed that Al2O3 nanoparticles (19 ± 5 nm) were homogeneously distributed onto the surface of curly‐shaped RGO flakes acting as a spacer between individual flakes. The high BET‐specific surface area of the analyzed composite (242.4 m2/g) together with very low open porosity indicates that RGO/Al2O3 nanocomposites have a very friable structure and show low tendency to agglomeration.

Effect of the Number and Orientation of Fractures on the P-Wave Velocity Diminution: Application on the Building Stones of the Rabat Area (Morocco)

This study is focused on two types of Moroccan rocks, among the most widely used as building stones: the calcarenite of Sale (CS) and the marble of oued Akrech (MA). The two rocks, lithologically different, show a clear contrast of their P-wave velocities (Vp): 3.90 vs 5.10 km/s at dry state and 4.29 vs 5.64 km/s at saturation. The “Artificial fractures” created in the two rock types reveal that their Vp undergo diminutions which the rates vary depending of the number and the plane orientation of the fractures. In the CS, Vp shows an increasing of cumulative diminution (Dc) according to the number of fractures, but with a variable rate of unitary diminution (Du) from one fracture to the other. This defines a linear regression with a low coefficient of determination (Dc = 10.18NbFr + 10.96; r2 = 0.87). The mode of the Vp evolution would be related to the roughness of fractures surface, which itself depends upon the petrographic nature of the calcarenite (friable structure, high porosity and heterogenous composition). The MA manifested an increasing Dc with a fairly constant rate of Du from a fracture to another, giving a regression line with a high coefficient of determination (Dc = 12.17NbFr – 10.69; r2 = 0.99). This steady diminution of Vp would be related to the granoblastic texture and the monomineral composition of the marble, which engender smoother fracture surfaces. The rates of Vp diminution also depend on the orientation plane of the fractures relative to the direction of wave propagation. The fractures parallel (θ = 0°) amplify slightly the Vp, playing a significant role of “waveguide”. The fractures oriented at 45° lead to a diminution lower than those of fractures oriented at 25° and 90°. The same trend of diminution, but at variable rates, appears on the samples of the two types of stones at dry and saturated state. This can be explained by the compressive nature of P-waves, which obey the physic laws of the transmission of the constraints in the solid mediums.

Tillage effects on topsoil structural quality assessed using X-ray CT, soil cores and visual soil evaluation

Soil structure plays a key role in the ability of soil to fulfil essential functions and services in relation to, e.g., root growth, gas and water transport and organic matter turnover. The objective of this paper was: (1) To quantify tillage effects on soil structural quality in the entire topsoil layer (0–20cm) using X-ray CT, visual evaluation and traditional core methods; and (2) To correlate pore network characteristics from X-ray CT imaging with the results from the visual evaluation and the core method. Samples were taken in May 2009 from a long-term rotation and tillage field experiment on a Danish sandy loam. The tillage treatments were direct drilling (D) and ploughing (P). For X-ray CT scanning, we sampled large soil cores (Ø=20cm, height=20cm) from the top layer. Small 100cm3 samples were taken from the 4–8 and 12–16cm layers for water content and bulk density measurements. Visual soil structure evaluation was carried out in the field at the same time as sampling. CT images (0.39×0.39×0.6mm3 voxels) were produced using a medical X-ray CT scanner. The visual assessment showed a good structural quality in the top 5–8cm for both treatments (Sq<2). A poorer soil structure was observed in lower part or the topsoil where a firm structure (Sq=2.9) was observed for D and relatively friable structure (Sq=2.2) for P. Lower bulk density was found for P than for D in the 4–8cm layer (1.34 and 1.52gcm−3, respectively), whereas relatively high bulk density values were observed for both treatments in the 12–16cm layers (1.50 and 1.56gcm−3, respectively). The X-ray CT image analysis showed that the P soil had more networks, branches and junctions but a lower degree of anisotropy and shorter average branch length than the D soil. The image data also confirmed a clear stratification of the 0–20cm topsoil layer for both tillage treatments. The stratification of the direct drilled soil was in accordance with our expectations whereas it was surprising for the ploughed soil. The dense lower topsoil layer for the ploughed soil was probably caused by compaction during secondary tillage and natural consolidation, and aggravated by a poor structural stability due to a low organic matter content. The visual soil evaluation scores were negatively correlated to soil porosity and number of pore networks estimated from X-ray CT imaging and positively correlated to the macropore characteristics of branch length and pore thickness.