GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • MDPI AG  (5)
  • 1
    Online Resource
    Online Resource
    Properties of Mortar Containing Recycled Fine Aggregate Modified by Microbial Mineralization
    MDPI AG ; 2022
    In:  Buildings Vol. 12, No. 11 ( 2022-11-21), p. 2035-
    Details
    In: Buildings, MDPI AG, Vol. 12, No. 11 ( 2022-11-21), p. 2035-
    Abstract: Microbial-induced mineralization deposition was used to improve the quality of the recycled fine aggregate (RFA) in this paper. In order to obtain a better improvement effect, the microbial mineralization conditions were first optimized. The effect of the pH value, temperature, bacterial concentration and calcium ion concentration on the mineralization ability of bacteria were investigated. The optimal microbial mineralization conditions were selected for the treatment of RFA and the microbial mineralization modification effect of RFA was evaluated based on the water absorption and crushing index. In addition, the natural fine aggregate (NFA), unmodified RFA and modified RFA were made into ordinary mortar, recycled mortar and modified recycled mortar, respectively. The workability, mechanical properties and chloride ion penetration resistance of mortars was investigated. Meanwhile, the precipitations formed by microbial mineralization were characterized using a scanning electron microscope (SEM) with an energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The pore structure of mortars was analyzed using the mercury intrusion porosimeter (MIP). The results showed that the bioprecipitations were mainly calcite calcium carbonate and the quality of the RFA was improved by microbial-induced calcium carbonate deposition. The water absorption and crushing index of the modified RFA decreased by 25.7% and 4.2%, respectively. Compared with the crushing index, the water absorption of the RFA was improved more obviously. The workability, mechanical performance, chloride ion penetration resistance and pore structure of the modified recycled mortar was improved. Compared with the recycled mortar, the fluidity of the modified recycled mortar was 7.3% higher, the compressive strength of 28 d was 7.0% higher and the 6 h electric flux was 18.8% lower. The porosity of the ordinary mortar, recycled mortar and modified recycled mortar was 16.49%, 20.83% and 20.27%, respectively. The strengthening of the modified recycled mortar performance may be attributed to the improvement of the mortar microstructure due to the enhancement of the RFA quality after the biotreatment.
    Type of Medium: Online Resource
    ISSN: 2075-5309
    URL: Article
    DOI: 10.3390/buildings12112035
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2661539-3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    A 2D Magneto-Acousto-Electrical Tomography Method to Detect Conductivity Variation Using Multifocus Image Method
    MDPI AG ; 2018
    In:  Sensors Vol. 18, No. 7 ( 2018-07-21), p. 2373-
    Details
    In: Sensors, MDPI AG, Vol. 18, No. 7 ( 2018-07-21), p. 2373-
    Abstract: As magneto-acoustic-electrical tomography (MAET) combines the merits of high contrast and high imaging resolution, and is extremely useful for electrical conductivity measurement, so it is expected to be a promising medical imaging modalities for diagnosis of early-stage cancer. Based on the Verasonics system and the MC600 displacement platform, we designed and implemented a MAET system with a chirp pulse stimulation (MAET-CPS) method and a focal probe was utilized for stepscan focus excitation to enhance the imaging resolution. The relevant experiments were conducted to explore the influence of excitation positions of the single-focus point, and the effect of the excitation position on the amplitudes of the conductivity variation was clearly demonstrated. In order to take advantage of the merits of multifocus imaging, we firstly proposed a single focus MAET system with a chirp pulse stimulation (sfMAET-CPS) method and a multifocus MAET system with a chirp pulse stimulation (mfMAET-CPS) method for high-resolution conductivity imaging, and a homogenous gelatin phantom with a cuboid-shaped hole was used to investigate the accuracy of mfMAET-CPS. Comparative experiments were carried out on the same uniform phantom by the sfMAET-CPS and the mfMAET-CPS, respectively. The results showed that: (1) the electrical conductivity distributions of the homogenous phantom with a cuboid-shaped hole were detected by the sfMAET-CPS but were easily affected by the focal point, which demonstrated that the sfMAET-CPS had a low imaging resolution. (2) Compared with the sfMAET-CPS, the imaging effect of the mfMAET-CPS was much better than that of the sfMAET-CPS. (3) A linear interpolation algorithm was used to process the 2D conductivity distribution; it increased the smoothness of the conductivity distribution and improved the imaging effect. The stepscan focus excitation and the linearly frequency-modulated theory provide an alternative scheme for the clinical application of MAET.
    Type of Medium: Online Resource
    ISSN: 1424-8220
    URL: Article
    DOI: 10.3390/s18072373
    Language: English
    Publisher: MDPI AG
    Publication Date: 2018
    detail.hit.zdb_id: 2052857-7
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Preparation, Characterization, and Terahertz Spectroscopy Characteristics of Reduced Graphene Oxide-Doped Epoxy Resin Coating
    MDPI AG ; 2021
    In:  Coatings Vol. 11, No. 12 ( 2021-12-06), p. 1503-
    Details
    In: Coatings, MDPI AG, Vol. 11, No. 12 ( 2021-12-06), p. 1503-
    Abstract: Reduced graphene oxide has attracted numerous interests due to its unique, superior electronic, optical, mechanical, and chemical properties. An epoxy resin with excellent mechanical and electrical properties can be obtained by doping with reduced graphene oxide to enhance the function of the polymer. Here, we prepared a uniform reduced graphene oxide/epoxy resin coating with a different reduced graphene oxide content and characterized it using a field-emission scanning electron microscope (FE-SEM), X-ray diffractometer (XRD), Raman, and Fourier transform infrared spectrometer (FTIR). Furthermore, the spectral characteristics of the composite coating in the terahertz band were discussed. The cross-sectional SEM results show that a fold structure with ductile failure was intensively formed due to the compatibility of graphene and polymer materials. Both the Raman G and Raman 2D peaks of reduced graphene oxide were confirmed using Raman spectrum testing. The diffraction peak of reduced graphene oxide at 24° disappeared within the reduced graphene oxide/epoxy resin coating, and a wide diffraction peak of the amorphous structure was formed together. Additionally, the intensity of the Raman spectrum increased significantly with increased reduced graphene oxide content, thereby making the surface electrical resistance of the coatings decrease exponentially. Additionally, the intensity of the terahertz time-domain signal and frequency-domain power spectrum linearly reduced with increased reduced graphene oxide concentration. However, the terahertz absorption coefficient and refractive index both increased gradually with increased reduced graphene oxide doping due to increased orientation polarization in the composite coating.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    URL: Article
    DOI: 10.3390/coatings11121503
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2662314-6
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 4
    Online Resource
    Online Resource
    Influence of Preoperative Serum Aspartate Aminotransferase (AST) Level on the Prognosis of Patients with Non-Small Cell Lung Cancer
    MDPI AG ; 2016
    In:  International Journal of Molecular Sciences Vol. 17, No. 9 ( 2016-09-03), p. 1474-
    Details
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 17, No. 9 ( 2016-09-03), p. 1474-
    Type of Medium: Online Resource
    ISSN: 1422-0067
    URL: Article
    DOI: 10.3390/ijms17091474
    Language: English
    Publisher: MDPI AG
    Publication Date: 2016
    detail.hit.zdb_id: 2019364-6
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 5
    Online Resource
    Online Resource
    Crack Self-Healing of Cement Mortar Containing Ureolytic Bacteria Immobilized in Artificial Functional Carrier under Different Exposure Environments
    MDPI AG ; 2022
    In:  Buildings Vol. 12, No. 9 ( 2022-09-01), p. 1348-
    Details
    In: Buildings, MDPI AG, Vol. 12, No. 9 ( 2022-09-01), p. 1348-
    Abstract: The ureolytic bacteria and nutrients were immobilized in the artificial functional carrier (AFC) and the self-healing cement mortar, based on the AFC-encapsulated bacteria, was prepared for this paper. The crack self-healing effect of mortars with and without bacteria under different exposure environments (standard curing, dry–wet cycle curing, and water curing) was investigated by the visual observation of surface and internal cracks, water permeability tests, and mechanical performance recovery. In addition, the internal healing products of the cracks were observed using the metallographic microscope. The results show that the mortar specimens containing ureolytic bacteria immobilized in artificial functional carrier have a higher crack area repair ratio, and better water tightness regain and recovery ratio of flexural strength compared with the control mortars under the same exposure environment. The self-healing effect of mortar cracks with and without bacteria is obviously affected by the exposure environments. The self-healing effect of the cracks are the best when the mortar specimens are cured in water, followed by dry–wet cycle curing, and the self-healing effect of the cracks is the worst in standard curing, indicating that the presence of water is necessary for crack self-healing. The mortar specimens with bacteria generate more repair products in the surface and interior of the cracks to greatly improve the self-repair ability of the specimens, which promotes the recovery of water tightness and mechanical performance.
    Type of Medium: Online Resource
    ISSN: 2075-5309
    URL: Article
    DOI: 10.3390/buildings12091348
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2661539-3
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...