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1
Cohen-Gould, Leona, and Thomas F. Robinson. "A Novel Method of Immuno-Gold Staining For TEM and HVEM." Proceedings, annual meeting, Electron Microscopy Society of America 43 (August 1985): 438–39. http://dx.doi.org/10.1017/s0424820100119016.
Анотація:
Advances in Immunochemistry allow for labelling of various tissue components with highly specific antibodies, that in turn may be labelled with marker substances such as flourescein for light microscopy, or any of a number of electron-dense substances, such as ferritin and colloldal gold, for localization with scanning and transmission electron miscroscopy. The methods used for transmission electron microscopy are designed to minimize damage to antigenic sites while preserving ultrastructure. The methods include embedding of the tissue in resins with low-temperature curing characteristics such as Polyethylene glycol (PEG) or Lowicryl K4M (Chemische Werke Lowl, F.R.G.). The tissue is embedded, sectioned, and mounted on grids. The Immuno-reactions are then carried out on these mounted sections.
2
Badaruddin, Mohammad. "Na2SO4 Induced Hot Corrosion of Aluminized Low Carbon Steel at 700 °C." Applied Mechanics and Materials 493 (January 2014): 761–66. http://dx.doi.org/10.4028/www.scientific.net/amm.493.761.
Анотація:
The oxidation kinetics of hot-dip aluminized AISI 1020 steel with Na2SO4 deposit was investigated at 700 °C for 49 h in static air. The scale morphologies were observed by means of metallograpy, scanning electron miscroscopy (SEM), electron dispersive spectroscopy (EDS) and X-ray analyses. The accelerated oxidation of aluminized steel was attributed to the formation of aluminum-sulphides which allowed the rapid diffusion of Fe ions in the aluminide layer to the formation of iron oxide. In addition, the Al-sulphides precipitations in the alumina scale causes the Al-depletion such that Al2O3 layer fails to form a protective layer. Consequently, the kinetics rate of aluminized was increased.
3
Rosa-Freitas, Maria Goreti, and Leonidas M. Deane. "The neotype of anopheles albitarsis (Diptera: culicidae)." Memórias do Instituto Oswaldo Cruz 84, no. 3 (September 1989): 289–302. http://dx.doi.org/10.1590/s0074-02761989000300002.
Анотація:
Anopheles albitarsis neotype is described from specimens collected in Baradero, Argentina, in Shannon's trap, in horse and pig stables and on the progeny of engorded females. The description includes illustrations of adult female, male and female genitalias, scanning electron miscroscopy of the eggs and complete chaetotaxy of pupa and larva. The importance for electing a neotype is based on the realization that An. albitarsis is a complex of cryptic species. It is an attempt to provide typt-locality specimens with which other memebers of the group can be compared.
4
Griffin, Brendan J. "Charge contrast imaging of material growth and defects in environmental scanning electron miscroscopy-linking electron emission and cathodoluminescence." Scanning 22, no. 4 (December 6, 2006): 234–42. http://dx.doi.org/10.1002/sca.4950220402.
5
Hardi, Amelina Dwika, Rahma Joni, Syukri Syukri, and Hermansyah Aziz. "Pembuatan Karbon Aktif dari Tandan Kosong Kelapa Sawit sebagai Elektroda Superkapasitor." Jurnal Fisika Unand 9, no. 4 (January 25, 2021): 479–86. http://dx.doi.org/10.25077/jfu.9.4.479-486.2020.
Анотація:
Pembuatan karbon aktif dari Tandan Kosong Kelapa Sawit (TKS) sebagai elektroda superkapasitor sudah diteliti. Karbon aktif dibuat dari proses karbonisasi dan aktivasi menggunakan Kalium Hidroksida (KOH). Karbon aktif TKS dikarbonisasi melalui pembakaran sampel pada suhu 400°C dan diaktivasi dengan KOH pada suhu 800°C dalam lingkungan gas nitrogen. Karbon aktif TKS dikarakterisasi menggunakan Energi Dispersive X-Ray (EDX), X-Ray Difraction (XRD), Scanning Electron Miscroscopy (SEM), Surface Area Analyzer (SAA). Komposisi unsur karbon yang dihasilkan dari karbon aktif TKS adalah sebesar 88,93 %wt. Struktur kristalit dari karbon aktif TKS menunjukkan struktur amorf pada sudut 2θ 26,20° dan 43,08°. Hasil analisis SAA dengan metode Brunauer-Emmet-Teller (BET) didapatkan luas permukaan karbon aktif TKS sebesar 898,229 m2/g. Pengukuran sifat listrik karbon Aktif TKS sebagai elektroda superkapasitor menggunakan larutan elktrolit H2SO4 1M dengan metoda Cyclic Voltametry (CV) didapatkan nilai kapasitansi spesifik sebesar 107,83 F/g. Preparation of activated carbon from Oil Palm Empty Fruit Bunch (TKS) as a supercapacitor electrode has been investigated. Activated carbon is made from carbonization and activation processes using Potassium Hydroxide (KOH). Activated carbon TKS is carbonized by burning the sample at 400°C and activated with KOH at 800°C in a nitrogen gas environment. Activated carbon TKS was characterized using Energi Dispersive X-Ray (EDX), X-Ray Difraction (XRD), Scanning Electron Miscroscopy (SEM), Surface Area Analyzer (SAA). The composition of the element carbon produced from activated carbon TKS is 88.93% wt. The crystallite structure of TKS activated carbon shows an amorphous structure at an angle of 2θ 26,20° and 43,08°. The results of the SAA analysis by the Brunauer-Emmet-Teller (BET) method showed that the surface area of the TKS activated carbon was 898.229 m2/g. Measurement of electrical properties of activated carbon TKS as a supercapacitor electrode using a 1M H2SO4 electrolyte solution with the Cyclic Voltametry (CV) method obtained specific capacitance values of 107.83 F /g.
6
Pontes do Nascimento, Nilson Machado, Bárbara Ronara Machado de Lima, José Roberto Zamian, Carlos Emmerson Ferreira da Costa, Luís Adriano Santos do Nascimento, Rafael Luque, and Geraldo Narciso da Rocha Filho. "Synthesis of Mesoporous Zn1−xMxAl2O4 Substituted by Co2+ and Ni2+ Ions and Application in the Photodegradation of Rhodamine B." Materials 13, no. 9 (May 6, 2020): 2150. http://dx.doi.org/10.3390/ma13092150.
Анотація:
A new mesoporous Zn1-xMxAl2O4 photocatalyst was prepared using the metal-chitosan complexation method with different degrees of Zn2+ cation substitution with cobalt and nickel ions (M = Co2+ and Ni2+). Characterization using X-ray diffraction (XRD), Infrared absorption spectrometry (FTIR), energy dispersion spectroscopy (EDS), diffuse reflectance spectrometry (DRS), scanning electron miscoscopy (SEM), transmission electron miscroscopy (TEM), N2 adsorption- desorption isotherms using the Barrett-Joyner-Halenda (BJH) method, thermogravimetric analysis (TG) and differential thermal analysis (DTA) confirmed the formation of the spinel phase and high purity for all samples. N2 adsorption/desorption and size pore distribution confirmed the high surface area. The photocatalytic activity of Zn1-xMxAl2O4 and the effect of replacing Zn2+ ions with Ni2+ and Co2+ on the degradation of rhodamine B under ultraviolet light were studied in detail. The sample containing 0.1 mol of cobalt had the highest removal rate reaching 83%, favored by surface area and material bandgap (109 m2 g−1 and 2.19 eV, respectively).
7
Apriani, Ida Nur Apriani, and Jarnuzi Gunlazuardi. "SINTESIS DAN KARAKTERISASI N DOPED TiO2 (N/TiO2) NANOTUBE SERTA UJI AKTIVITAS FOTOKATALISIS TERHADAP ZAT WARNA RHODAMIN B." Jurnal Teknologi dan Manajemen 19, no. 1 (April 8, 2021): 27–32. http://dx.doi.org/10.52330/jtm.v19i1.21.
Анотація:
Telah dilakukan sintesis fotokatalis N/TiO2 bermofologi nanotube dengan metode anodisasi menggunakan ammonium nitrat (NH4NO3) sebagai sumber dopan pada berbagai variasi konsentrasi (0,5M , 1M, 2M), dilanjutkan dengan kalisinasi pada suhu 4500C selama 2 jam untuk mendapatkan fasa kristal anatase. Karakterisasi dilakukan menggunakan Scanning Electron Miscroscopy (SEM), Fourier Transform Infra Red (FT-IR), X-ray Diffraction (XRD), dan DRS (Diffused Reflectant Spectrometry) UV-Vis. Pengujian Linear Sweep Voltametri dan Multi Pulse Anperiometri pada fotokatalis N/TiO2 telah berhasil diterapkan untuk degradasi senyawa Rhodamin B menggunakan sinar UV maupun sinar tampak. Aplikasi dari uji fotoelektrokatalisis menggunakan sinar tampak untuk N/TiO2-NT memberikan hasil eliminasi sebesar 47,86%, sedangkan bila menggunakan TiO2 nanotube tanpa dopan eleminasi hanya sebesar 25,49%. Hal ini menunjukkan bahwa proses doping yang dilakukan telah berhasil menyisipkan nitrogen kedalam matrik TiO2 nanotube dan memperbaiki kinerja fotokatalisis nya di daerah sinar tampak.
8
Marina, Dewi, and Widodo Budi Kurniawan. "Karakteristik Karbon Aktif Limbah Kulit Lada (Piper Nigrum L) sebagai Elektroda Superkapasitor." Jurnal Riset Fisika Indonesia 2, no. 1 (December 30, 2021): 7–14. http://dx.doi.org/10.33019/jrfi.v2i1.3171.
Анотація:
Pemenuhan kebutuhan energi dibutuhkan suatu piranti penyimpan yang memiliki kapasitansi spresifik yang tinggi yaitu superkapasitor. Superkapasitor adalah perangkat penyimpan muatan yang memiliki kapasitansi spesifik yang tinggi. Dalam penelitian ini telah dilakukan preparasi dan karakterisasi karbon aktif dari limbah kulit lada sebagai bahan elektroda superkapasitor. Karbon diaktivasi dengan variasi aktivator NaOH 1 M, 3 M dan 5 M dilanjutkan dengan pemanasan pada suhu 700˚ C selama 3 jam dengan dialiri gas nitrogen (N2). Karbon selanjutnya dikarakterisasi menggunakan Scanning Electron Miscroscopy-Energy Dispersive Spektroscopy (SEM-EDS), Brunauer-Emmett-Teller (BET) dan pengukuran kapasitansi menggunakan metode Cyclic Voltametry (CV). Hasil pengujian menunjukkan karbon aktif limbah kulit lada berpori dengan bentuk pori bulat pada sampel 3 M dan 5 M, sedangkan pada 1 M terdapat pori berongga yang pipih dan panjang. Hasil EDS setiap sampel memiliki kandungan unsur karbon (C) secara berurut yaitu 77,57%, 75,96%, dan 74,62%. Hasil BET menunjukkan luas permukaan maksimum sebesar 149,319 m2/g. Kapasitansi elektroda superkapastitor tertinggi diperoleh pada konsentrasi 5 M dengan laju scan 1 mV/s yaitu 12,68 F/g.
9
Almuchty, Alissa Putri. "PEMANFAATAN KULIT RAMBUTAN (Nephelium lappaceum) SEBAGAI ADSORBEN LOGAM TIMBAL (Pb)." Lingkar : Journal of Environmental Engineering 1, no. 1 (July 1, 2020): 1–6. http://dx.doi.org/10.22373/ljee.v1i1.843.
Анотація:
Present of lead as a heavy metal can be harmful to health. One possible method to reduce the presence of lead metal content is obtained through the adsorption process using adsorbent from rambutan rind. This study aimed to determine the effectiveness of activated charcoal from rambutan rind in absorbing lead metal with variations of difference adsorbent mass and stirring time. In this study, chemical activation was carried out by soaking the rambutan rind using 0.1 M NaOH solution for 24 hours. Adsorbents were characterized using Scanning Electron Miscroscopy (SEM) to determine the surface structure and particle size of the adsorbent. Furthermore, the adsorption process was carried out by contacting the adsorbent with lead solution based on the time difference of 10, 20 and 30 minutes and the adsorbent mass of 5, 10 and 15 grams. Based on the test results, the lowest concentration of lead was 1.692 and the highest concentration was 2.983. The most effective absorption of lead was at a level of 15 grams with a stirring time of 30 minutes with an absorption effectiveness of 83.30%.
10
Letícia Molteni Aguiar, Lilian Eiko Maekawa, Adriana Chung, and Maria Renata Giazzi Nassri. "Evaluation of dentin cleansing by a detergent derived from castor oil (Ricinus communis) used as root canal irrigant: a scanning electron miscroscopy study." RSBO 7, no. 4 (December 22, 2011): 445–9. http://dx.doi.org/10.21726/rsbo.v7i4.1175.
Анотація:
Introduction and objective: To evaluate, by scanning electron microscopy (SEM), the cleaning of root canal walls after biomechanical preparation and irrigation with castor oil (Endoquil®) and 0.5% sodium hypochlorite (NaOCl). Material and methods: Fifteen maxillary incisors were subjected to standardized root canal instrumentation with different irrigants (n = 5): G1 – Endoquil; G2 – 0.5% NaOCl; G3 – saline solution (control). After instrumentation, the teeth were prepared for SEM analysis (X 2000 original magnification) to evaluate the cleaning of cervical, middle and apical thirds. The area analyzed was quantified according to the percentage of open and closed tubules and data were statistically analyzed by ANOVA and Kruskal Wallis tests. Results: Statistical analysis showed that Endoquil was similar to 0.5% NaOCl at the apical third. However, there was statistically significant difference at the cervical and middle thirds, between these two groups. Conclusion: It was concluded that Endoquil presented better results at the middle third while 0.5% NaOCl presented better results at the cervical third; at the apical third, both irrigants were similar.
11
Posadas, Gabriel A., Paul R. Broadway, Justin A. Thornton, Jeffery A. Carroll, Amanda Lawrence, Jimmie R. Corley, Amber Thompson, and Janet R. Donaldson. "Yeast Pro- and Paraprobiotics Have the Capability to Bind Pathogenic Bacteria Associated with Animal Disease1." Translational Animal Science 1, no. 1 (February 1, 2017): 60–68. http://dx.doi.org/10.2527/tas2016.0007.
Анотація:
Abstract Live yeast probiotics and yeast cell wall components (paraprobiotics) may serve as an alternative to the use of antibiotics in prevention and treatment of infections caused by pathogenic bacteria. Probiotics and paraprobiotics can bind directly to pathogens, which limits binding of the pathogens to the intestinal cells and also facilitates removal from the host. However, knowledge of bacterial binding, specificity, and/or capability is limited with regard to probiotics or paraprobiotics. The goal of this study was to characterize the qualitative and quantitative nature of two Saccharomyces cerevisiae probiotics and three S. cerevisiae paraprobiotics to adhere to thirteen different pathogenic bacteria using scanning electron miscroscopy and filtration assays. On average, the yeast probiotics (LYA and LYB) exhibited overall greater (P < 0.05) adhesion to the pathogenic bacteria tested (41% and 34%) in comparison to paraprobiotics (23%, 21%, and 22%), though variations were observed between pathogens tested. The ability of Salmonella and Listeria to utilize components of the yeast as a nutrient source was also tested. Bacteria were cultured in media with limited carbon and supplemented with cell free extracts of the probiotics and paraprobiotics. Salmonella exhibited growth, indicating these pathogens could utilize the yeast lysates as a carbon source. Listeria monocytogenes had limited growth in only one of the lysates tested. Together, these data indicate that the interaction between probiotics and paraprobiotics occurs in a strain dependent mechanism. Administration of probiotics and paraprobiotics as therapeutics therefore needs to be specific against the bacterial pathogen target.
12
Idris, Aida I. Mohamad, Siti Mazlina Mustapa Kamal, Alifdalino Sulaiman, Rozita Omar, and Munira Mohammad. "Characterization of Cellulose Acetate Membrane at Different Thicknesses on Sucrose Concentration by Forward Osmosis." ASEAN Journal of Chemical Engineering 22, no. 2 (December 29, 2022): 337. http://dx.doi.org/10.22146/ajche.77350.
Анотація:
Forward osmosis (FO) requires a specific membrane structure for applications like juice concentration. The phase inversion method was used to make cellulose acetate (CA) FO membranes. The solvents used were acetone and 1,4-dioxane. Additives included polyvinylpyrrolidone (PVP), methanol, and maleic acid were used in the preparation of CA membrane, which make it easier to improve a FO membrane's permeability. The performance of fabricated FO membrane and their morphology were evaluaed with different casting thicknesses of 150, 200, and 250 µm. Experiment works begins with an hour of membrane flux testing, deionized water was used as feed solution and 1 M NaCl as draw solution. The membrane was then used to concentrate 0.5 M sucrose with NaCl for 240 minutes (2 M). Contact angle, porosity, and scanning electron miscroscopy (SEM) were used to characterize membrane properties and morphology. High water flux (2.25 L/m2hr) and high porosity (75.86%) were found at 200 µm casting thickness. Water permeability of sucrose concentration at 200 µm casting thickness had the highest flux (2.39 L/m2hr). The results also show that flux values vary with membrane thickness. All membranes were hydrophilic with contact angles below 90°. A 200 µm casting thickness produces a membrane with smooth and evenly distributed pores, according to morphology analysis. Structural parameter (S) values had a proportional relationship with the FO membrane thickness, which thinner membrane potentially reduces the internal concentration polarization (ICP).
13
Mijiritsky, Eitan, Letizia Ferroni, Chiara Gardin, Oren Peleg, Alper Gultekin, Alper Saglanmak, Lucia Gemma Delogu, et al. "Presence of ROS in Inflammatory Environment of Peri-Implantitis Tissue: In Vitro and In Vivo Human Evidence." Journal of Clinical Medicine 9, no. 1 (December 23, 2019): 38. http://dx.doi.org/10.3390/jcm9010038.
Анотація:
Analyses of composition, distribution of cellular and extracellular matrix components, and molecular analysis of mitochondria related genes of bone loss in the presence of inflammatory environment in humans was the aim of the present project. As a human model we chose peri-implantitis. Morphological analyses were performed by means classical histological, immunohistochemical, and SEM (scanning electron miscroscopy) test. Gene expression analysis was performed to evaluate epithelium maturation, collagen fiber production, and genes related to mitochondrial activity. It was found that a well-defined keratinocyte epithelium was present on the top of all specimens; a distinct basal lamina was present, as well as desmosomes and autophagic processes related to the maturation of keratinocytes. Under this epithelium, a full inflammatory cell infiltrate was present for about 60% of the represented by plasma cells. Collagen type I fibers were present mainly in the form of fragmented cord tissue without cells. A different distribution of blood vessels was also present from the apical to the most coronal portion of the specimens. High levels of genes related to oxidative stress were present, as well as the activation of genes related to the loss of ability of osteogenic commitment of Mesenchymal stem cells into osteoblasts. Our study suggests that peri-implantitis lesions exhibit a well defined biological organization not only in terms of inflammatory cells but also on vessel and extracellular matrix components even if no difference in the epithelium is evident, and that the presence of reactive oxygen species (ROS) related to the inflammatory environment influences the correct commitment of Mesenchymal stem cells.
14
Cabała, Jerzy, Rafał Warchulski, Dariusz Rozmus, Dorota Środek, and Eligiusz Szełęg. "Pb-Rich Slags, Minerals, and Pollution Resulted from a Medieval Ag-Pb Smelting and Mining Operation in the Silesian-Cracovian Region (Southern Poland)." Minerals 10, no. 1 (December 28, 2019): 28. http://dx.doi.org/10.3390/min10010028.
Анотація:
Since the 12th century in the Silesian-Cracovian area, lead, litharge, and silver have been produced by the pyrometallurgical processing of Pb-Ag-Zn ore. Slags and soils contaminated with heavy metals (Zn, Pb, Cd, Fe, Mn, As) were the subject of this research. Samples were collected during archaeological works in the area of early medieval metallurgical settlement. The main goals of the analyses (Scanning Electron Miscroscopy-Energy Dispersive Spectroscopy (SEM-EDS), Electron Probe Microanalyzer (EPMA), X-ray diffraction (XRD), Atomic Absorption Spectroscopy (AAS)) were the determination of the mineralogical composition of furnace batches and smelting temperatures and conditions. In soils, the anthropogenic phases enriched in Pb, Zn, Fe, Mn, P, and primary minerals like goethite, ferrihydrite, sphalerite, galena, smithsonite, minrecordite, cerussite, gypsum, anglesite, jarosite, and hemimorphite were identified. The soil from former metallurgical settlements contained up to 1106 mg·kg−1 Pb, 782 mg·kg−1 Zn, 4.7 mg·kg−1 Cd in the fine fraction. Much higher heavy metal concentrations were observed in the waste products of ore rinsing, up to 49,282 mg·kg−1 Pb, 64,408 mg·kg−1 Zn, and 287 mg·kg−1 Cd. The medieval smelting industry and Pb-Ag-Zn ore processing are marked by highly anomalous geochemical pollution (Pb, Zn, Cd, Fe, Mn, Ba) in the topsoil. The methods of mineralogical investigation, such as SEM-EDS or EMPA, can be used to identify mineralogical phases formed during metallurgical processes or ore processing. Based on these methods, the characteristic primary assemblage and synthetic phases were identified in the area polluted by medieval metallurgy and mining of Pb-Ag-Zn ores, including MVT (Mississippi Valley Type) deposits. The minerals distinguished in slags and the structural features of metal-bearing aggregates allow us to conclude that batches have included mostly oxidised minerals (PbCO3, ZnCO3, CaZn(CO3)2, FeOOH), sulfides (PbS and ZnS) and quartz (SiO2). The laboratory experiment of high-temperature heating of the examined slags showed that smelting temperatures used in the second half of 13th century were very high and could have reached up to 1550 °C. The results indicate, that geochemical and mineralogical methods can be used to obtain important information from archaeological sites, even after archaeological work has long ceased.
15
Akinmosin, A., and C. V. Melifonwu. "Sedimentological and Scanning Electron Miscroscopic Descriptions of Afowo Oil Sand Deposits, South Western Nigeria." GeoScience Engineering 63, no. 4 (December 1, 2017): 20–32. http://dx.doi.org/10.1515/gse-2017-0019.
Анотація:
AbstractSedimentological and scanning electron microscopic analyses of some shallow reservoir tar sand samples in parts of Southwestern Nigeria were carried out with the aim of characterizing the reservoir properties in relation to bitumen saturation and recovery efficiency. The production of impregnated tar from the sands requires the reservoir to be of good quality. A total of thirty samples were collected at different localities within the tar sand belt (ten out of these samples were selected for various reservoir quality analyses based on their textural homogeneity). The result of particle size distribution study showed that bulk of the sands is medium – coarse grained and moderately sorted. The grain morphologies are of low to high sphericity with shapes generally sub-angular to sub-rounded, implying that the sands have undergone a fairly long transportation history with depositional energy having a moderate to high velocity. The quartz content was made up of about 96% of the total mineralogical components; the sediments of the Afowo Formation can be described to be mineralogically and texturally stable. The result of the scanning electron microscopy (SEM) analysis revealed that the oil sands contained minerals which had been precipitated and occurred as pore filling cement; these minerals include sheet kaolinite, block kaolinite, vermiform kaolinite, pyrite crystals and quartz. The SEM images also showed micro-pores ranging from 0.057µm to 0.446µm and fractures. The study showed that the clay minerals contained in the Afowo reservoir rocks were mainly kaolinite. Kaoline unlike some other clays (e.g Montimorillonite) does not swell with water, hence it is not expected to have any negative effects on the reservoir quality, especially during enhanced oil recovery operations.From overall results of the reservoir quality assessment, Oso J4 and Gbegude sands should be expected to make better reservoirs with good oil recovery efficiency due to their low content of fines and better sorting characteristics when compared to sediments of other areas.
16
Yuan, Hong-Chien, Walter Kutschera, Tze-Yue Lin, Peter Steier, Christof Vockenhuber, and Eva Maria Wild. "Investigation of a Chinese Ink Rubbing by 14C AMS Analysis." Radiocarbon 45, no. 1 (2003): 1–7. http://dx.doi.org/10.1017/s0033822200032331.
Анотація:
The date of a Chinese ink rubbing was determined using radiocarbon accelerator mass spectrometry (AMS) to be in the range from AD 1480 to AD 1670 (95.4% confidence limit). Together with a scanning electron miscroscope (SEM) analysis of the ink and a comparative study of the Chinese characters, it was determined that the ink rubbing must have been performed before Emperor Kang Hsi (AD 1662–1722), who ruled at the beginning of the Chin Dynasty. On the other hand, the stone stele, from which the ink rubbing was produced, was carved in AD 531, which is consistent with an analysis of some erased characters. Such analysis seems to be useful to help clarify possible forgeries of these art objects.
17
Hurst, George, Juan Maria González-Carballo, Lubomira Tosheva, and Silvia Tedesco. "Synergistic Catalytic Effect of Sulphated Zirconia—HCl System for Levulinic Acid and Solid Residue Production Using Microwave Irradiation." Energies 14, no. 6 (March 12, 2021): 1582. http://dx.doi.org/10.3390/en14061582.
Анотація:
The synergistic conversion of Miscanthus xGiganteous with sulphated zirconia and dilute hydrochloric acid was investigated. The sulphated zirconia was prepared using H2SO4 impregnation and characterised using X-ray Diffraction (XRD), Energy-dispersive X-ray (EDX), Scanning Electron Miscroscope (SEM) spectroscopy and nitrogen adsorption–desorption measurements. The microwave-assisted reaction was evaluated at various temperatures, reaction times and catalyst-to-biomass ratios, with and without the presence of trace HCl in the solution medium for the conversion of Miscanthus xGiganteous to levulinic acid. The highest levulinic acid yield of 63.8% was achieved at 160 °C, 80 min and a 2:1 catalyst-to-biomass ratio, with 10 mM HCl. The catalyst recyclability was investigated with and without calcination, finding that significant humin deposition on the catalyst surface likely caused catalyst deactivation. The post-reaction solid residue was also characterised using SEM, EDX, XRD, elemental composition and nitrogen adsorption–desorption measurements. Findings indicate that this residue could potentially be used as a soil amendment or as a fuel source. The synergistic conversion of real lignocellulosic biomass with sulphated zirconia and trace hydrochloric acid showed remarkable promise and should be investigated further.
18
Roy, Julie L., and William B. McGill. "Characterization of disaggregated nonwettable surface soils found at old crude oil spill sites." Canadian Journal of Soil Science 78, no. 2 (May 1, 1998): 331–44. http://dx.doi.org/10.4141/s97-039.
Анотація:
We characterized some of the physical, chemical, and microbiological properties of soils that have become severely water-repellent and disaggregated several years or decades following oil contamination. A growing number of patches (usually <2 ha) of disaggregated water-repellent soils have recently been discovered throughout the province of Alberta at 20 to 50-yr-old crude oil spill sites. The disaggregated water-repellent soil is usually confined to a dry and powdery surface layer 10 to 15 cm deep, which no longer smells, feels, or looks like it contains any oil. These soils appear to have permanently lost the ability to support plant growth and recover through natural processes. We analyzed samples of disaggregated water-repellent and adjacent normal soils from three old crude oil spill sites to provide a background set of information about these poorly known soils and assist in the development of hypotheses concerning the development and persistence of soil water repellency and structural degradation. Compared with normal adjacent soils, disaggregated nonwettable soils are characterized by: (1) a strong resistance to wetting, as determined by the molarity of ethanol droplet (MED) test; (2) a smaller population of viable and culturable microorganisms, which contains at least some representatives from nonspore-forming bacterial genera; (3) a high content of mineral N and total C, a comparable pH and ratio of exchangeable cations, but a lower cation exchange capacity; (4) a slightly lower clay content, as determined by the Bouyoucos hydrometer method; (5) a comparable water desorption behaviour following forced saturation with water; (6) dry aggregates of a smaller mean weight diameter (MWD), as determined by dry sieving and scanning electron miscroscopic (SEM) analyses; (7) slightly less pronounced thermal reactions when heated up to 525 °C, as determined by differential thermal analyses (DTA); and (8) a reduced ability to support plant growth. From these observations, we infer that disaggregated water-repellent soils found at old crude oil spill sites do not differ appreciably from normal adjacent soils in terms of their inorganic chemistry. Nonwettable and adjacent wettable soils differ mostly in terms of some physical and biological characteristics, which probably stem from differences in the quality of the organic matter they contain. Key words: Crude oil spills, petroleum hydrocarbons, soil water repellency, soil disaggregation, soil hydrophobicity
19
Moon, W., SH Chung, and J. Chang. "Effect of Deep Margin Elevation on Interfacial Gap Development of CAD/CAM Inlays after Thermomechanical Cycling." Operative Dentistry, November 10, 2021. http://dx.doi.org/10.2341/20-310-l.
Анотація:
SUMMARY The aim of this study was to evaluate interfacial gap formation of CAD/CAM lithium disilicate inlay margins before and after thermomechanical loading. Methods and Materials: Mesio-occlusal-distal cavities were prepared on 12 extracted mandibular molars. The gingival margin of one proximal box was elevated with resin modified glass ionomer (RMGI) by a height of 2 mm (Group E [elevation]), and the margin of the other side served as a control (Group NE [no elevation]). Lithium disilicate computer-aided design and computer-aided manufacturing (CAD/CAM) inlays were fabricated and bonded with a self-adhesive resin cement. An aging process was simulated on the specimens under thermomechanical cycling by using a chewing simulator. Marginal integration was evaluated under scanning electron miscroscopy (SEM) using epoxy resin replicas before and after cycling. Marginal areas were stained with silver nitrate solution, and the volumetric gap was measured at the bonded interfaces using microcomputed tomography (CT) before and after cycling. Statistical analyses were performed using paired t-tests, the Wilcoxon signed rank test, and the Mann–Whitney test (a<0.05). Results: SEM showed marginal discontinuities in Group NE that increased after thermomechanical cycling. Micro-computed tomography exhibited three-dimensional dye-penetrating patterns at the interfaces before and after cycling. Interfacial disintegration was larger in Group NE before cycling (p<0.05). Thermomechanical cycling increased the gaps in both Groups NE and E (p<0.05). The gap increment from thermomechanical cycling was larger in Group NE (p<0.05). Conclusions: Thermomechanical cycling induced interfacial disintegration at the lithium disilicate CAD/CAM inlays, with deep proximal margins. Margin elevation with RMGI placement reduced the extent of the interfacial gap formation before and after the aging simulation.
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Zilkifli, Firdaus, and Nurazuwa Md Noor. "Preliminary Experimental Work on Concrete-Fly Ash Compressive Strength Blended with Seawater as Mixing Water." International Journal of Integrated Engineering 15, no. 6 (November 28, 2023). http://dx.doi.org/10.30880/ijie.2023.15.06.013.
Анотація:
Fly ash is widely used in the construction sector, but application with seawater has not fully utilised. Seawater is used in construction to minimise the scarcity of drinking water. The concrete was strengthened by the application of fly ash. Seawater replacing 100% tapwater as mixing water. Meanwhile, fly ash was substituted with ordinary Portland cement at 10%, 20%, 30%, and 40%. To achive the objective, the 100 mm x 100 mm x 100 mm cube size with 0.33 water-cementitious ratio were prepared. All series of mixture were casted and cured in water for 7 and 28 days. The fly ash blended with seawater in concrete were investigate through its compressive strength. In addition, scanning electron miscroscope were carried out to capture surface image of the specimen. The experimental work result shows, with the existence of fly ash in concrete mixture, it decreases workability, density and compressive strength. Though the decreasing pattern was seen in every series, the structural strength was still deemed adequate.