ALBERT

Beschreibung: Aiming to enhance the CO 2 capture capacity and the anti-attrition property of the CaO-based sorbents simultaneously, a novel CaO-based sphere was prepared by extrusion-spheronization method using Ca(OH) 2 powder with glucose templated. The CO 2 capture characteristics and attrition resistance property of the sorbent were examined and the microstructure of the sorbents was also analyzed. The results outline that the obtained spherical sorbents has outstanding anti-attrition performance compared to limestone sorbent. After 100 cycles, all of the templated sorbents hold a CO 2 capture capacity of over 0.18 g of CO 2 /g of sorbents, which was over one time higher than that of limestone. The optimum templating rate of glucose in the sorbent is 1-5 wt. %.

Beschreibung: In a hydrogen network, sinks and sources are generally connected to reactors or purifiers, and their compositions and flow rates are affected by these equipments. The relationship between these streams deserves to be studied based on the integration of the hydrogen network to identify the feasible and optimal operating conditions of the reactors and purifiers. Equations are deduced to describe the quantitative relationship among the hydrogen consumption, the hydrogen concentration and flow rates of coupled sink and source, the purification feed and purified product. Based on this, the Δ F SKq ~ F pur quantitative diagram is plotted to identify the feasible region and the variation trend line. The purification and hydrogen consuming reactor parameters can be optimized in the design and operation stage of a hydrogen network. The case study shows that the proposed method is simple, easy understanding, and can be applied to identify the variation trend line and feasible region accurately without tedious calculation.

Beschreibung: Rubber seed oil (RSO) is a high potential feedstock for the production of biodiesel fuel (BDF) in Asia. In this study, the transesterification using fatty acid methyl esters (FAMEs) as a co-solvent was developed for a BDF production from RSO with high content of free fatty acids (FFAs) (35.6 wt%). The homogeneous system (FAMEs/triglyceride/methanol) was attained when FAMEs content was more than 30 wt%. After esterification of RSO, the crude RSO obtained was transesterified using 34 % content of FAMEs as a co-solvent. The reaction completed in 30 min at 40 o C. The quality of BDF with 99.2 % FAMEs content satisfied the criteria in the EN 14214/JIS K2390 standards. These results suggest that FAMEs converted from FFAs can be applied as a co-solvent, and thus reused for the BDF production.

Beschreibung: An improved model to predict ·OH yield in hydrodynamic cavitation for wastewater treatment is developed. Relaxing the chemical equilibrium assumption, the model can estimate the global average ·OH yield during the whole oscillation cycle of all bubbles by considering radicals diffusion, cavitation event rate and bubble radius distribution. Reliability of the model is verified by comparing with experimental data in literature in terms of geometric and operating parameters. The results show that the maximum ·OH yield 1.2743×10 -4 mol·m -3 ·s -1 is achieved at optimal upstream pressure 3.6×10 5 Pa, while increasing downstream pressure always enhances ·OH yield. Decreasing the hole and pipe diameters benefits ·OH yield. Finally, a relevant correlation is developed for the design of cavitation reactors.

Beschreibung: To optimize the performance of oil free reciprocating piston compressors, the leakage flow through the piston seal has to be minimized. Therefore, the effect of the geometrical parameters and shapes of labyrinth seals on the leakage flow is investigated. The main geometrical parameters and shapes were investigated by means of computational flow dynamics (CFD) simulations. The optimum geometries obtained from the simulations are experimentally tested on a compressor rig. The rectangle labyrinth has the lowest leakage followed by a novel semi-circle geometry and the triangle geometry has the highest leakage flow among the labyrinths. The straight seal has the highest leakage flow rate. It can be concluded that the rectangle labyrinth, reduces the leakage flow rate in the most efficient way.

Beschreibung: Electro discharge machining (EDM) is an important manufacturing process for hard-to-cut-materials like nickel based alloys, e.g. alloy 718. Its high yield strength at high temperature makes it suitable as material for manufacturing of pressure vessels for high pressure / high temperature applications, in particular for ammonothermal pressure vessels. This report first summarizes the relationship between microstructure and properties of alloy 718 for practitioners. Second, it focuses on the metallographic description of alloy 718 surfaces proceeded by EDM and its behavior during use as equipment for ammonoacidic systems. Furthermore, this article includes the finding of suitable post processing, namely honing, to achieve high stability of the surface at high pressure atmosphere.

Beschreibung: This work proposed the route that bio-oil was directionally converted into phenol by means of coupling the catalytic cracking of the bio-oil and the hydroxylation of the bio-oil based benzene-rich aromatics. High selectivity of 90.5 C-mol % phenol in the resulting organic liquid was achieved with an almost complete conversion of the bio-oil. Co-cracking of bio-oil with methanol over the Zn-modified zeolite significantly enhanced the yields of aromatics, and decreased the deactivation of catalyst during the catalytic cracking of bio-oil. The yield of phenol depended on the metal oxides catalysts, temperature and reaction time during the hydroxylation of the benzene-rich aromatics. The reaction pathway for converting the bio-oil into phenol was addressed based on the products identified and the catalyst’s characterizations.

Beschreibung: Magnetic γ-Fe 2 O 3 catalysts were prepared by the microwave-assisted co-precipitation method utilizing direct-titrate and back-titrate precipitation technique with different precipitants ((NH 4 ) 2 CO 3 , NaOH, Na 2 CO 3 , and NH 4 OH), which were investigated in the selective catalytic reduction of NO x with NH 3 . The best γ-Fe 2 O 3 catalyst prepared method was direct-titration, using NH 4 OH as the precipitant, which exhibits a high de-NO x efficiency of above 90% at 325~400 °C. The direct-titration using NH 4 OH as the precipitant is effective to maintain the proper crystallization degree of γ-Fe 2 O 3 , improve the pore structure, and suppress the formation of α-Fe 2 O 3 phase, which are of benefits to get tiny and uniform discrete γ-Fe 2 O 3 particles with high activity in SCR. Meanwhile, NH 4 + -based precipitants in direct-titration leads to an increase of surface O/Fe atom ratio and more lattice oxygen sites are exposed to the crystal surface.

Beschreibung: Synthetic biomaterials submitted to new structural technologies have become ideal for the recovery of traumatized bone tissues and some bone substitutes such as bioactive glass, β-Tricalcium phosphate (β-TCP) and amorphous calcium phosphate (ACP) are being used in areas of tissue defects. For this study, ACP was produced in the form of fibers and then submitted to cytotoxicity testing. A sample of ACP was inserted into the mandibular region of a patient with a lost implant so after removal and curettage, the remaining bone site was filled with the ACP biomaterial. Preliminary cytotoxicity test was negative. After 15 weeks of healing, a titanium implant was inserted at the site. Clinical and radiographic follow-up was conducted for 12 months and sequential radiographic analyses revealed tissue formation resembling spongy bone. Images under immunohistochemistry demonstrated efficient deposition and osteoconduction of the newly deposited tissue. Residual portion of the CaO:P 2 O 5 outer layers served as a substrate for osteoid matrix deposition, aiding growth, and the results of fiber absorption favored maturation of the new bone tissue. Bone repair was benefited by the existence of the ACP in the form of fibers. Samples taken from the grafted site demonstrated that the ACP favored the formation and maturation of the newly deposited tissue with few residual remnants of its constituents. In addition, the ACP in fibers allows its use in simple cases such as alveoli after dental extraction or small bone defects accelerating local healing.

Beschreibung: High-purity distillation columns present the challenges of nonlinearity, interactions, directionality and ill-conditioning for the control systems, and therefore exhibit poor controller performance. This work investigates the effects of these challenges on the performance of model predictive control in operations near-azeotropic regions. A dynamic model of a pilot-scale distillation column is simulated using Aspen PLUS Dynamics® and controlled by a linear model predictive controller using MATLAB-Simulink® interface. Results indicate that as the system moves towards the azeotropic region, the nonlinearity, directionality, and interactions of the system increase. A significant decline is also observed in the control performance of the system since the controller incurs as high as 175% overshoots and 80% offsets for negative and positive setpoint changes respectively. The Integral Time Absolute Errors are up to 16 times higher near azeotropic region than that of the regions which are away from the azeotropic point. Only a small operating range is, therefore, able to ensure sufficient controllability near azeotropic region.

Beschreibung: Integrated distillation equipment, like the Petlyuk column, offers enormous energy saving potential. However, high complexity and few available experimental data lead to high uncertainty. This paper presents an integrated approach to reduce this risk. The first study on the influence of relative volatilities on the process behavior is presented. Comprehensive pilot plant experiments are displayed for three different component systems of linear alcohols. The experiments are carried out for a wide range of operating conditions. Results show a stable operation and high product purities. Based on the experimental data a predictive non-equilibrium stage model for column design is validated. Experiment and simulation show good agreement.

Beschreibung: The changes in viscosity exhibited upon mixing remain one of the major challenges for substance property prediction. Viscosity often drastically changes after even small changes in concentration of one of the compounds in the mixture. The viscosity behavior of mixtures of ionic liquids with water has been studied. First, a generalized evaluation of the shape of the viscosity-concentration-curves has been done. About a tenth of the systems studied, exhibited maxima or inflection points of the curve. The simple logarithmic mixing rule turns out to be applicable as a first approximation for many systems. However, it tends to underestimate mixture viscosity. Following these results, parameters for a group contribution method were fitted and evaluated. This method is based on the Grunberg and Nissan extension of the logarithmic mixing rule.

Beschreibung: The surface charge of metal oxides in the solution phase may be a driving force for crystallization. We prepare composite particles using the principle of heterogeneous nucleation on a metal surface with charge density. The electrical properties of the silica gel particles in an electrolyte solution were controlled by pH, and the zero charge point and charge density of silica gel particles were determined by titration. The morphology of glycine particles on the silica gel surface depended on the electrical properties of the silica gel particle, resulting in alteration of the glycine polymorph. Powder X-ray diffraction showed that γ-glycine was present at low pH and α-glycine was present at high pH. The polymorphism arose from the abundance ratio of solute ions and solution structure.

Beschreibung: The purification of recombinant L-asparaginase II from an E. coli fermentation broth was carried out by the solvent freeze out technology in lab scale. Preliminary crystallization conditions were determined using batch crystallization screening. The purification of L-asparaginase II was performed afterwards. Protein crystals with rhombic shape were obtained from the solvent freeze out crystallization using 20% (volume percent) ethanol. The purity of the crystals was evaluated by SDS-PAGE together with UV-Spectrophotometer. It was found that DNA could be mostly removed using solvent freeze out crystallization. Furthermore, the activity test showed that the enzymatic activity was preserved as well.

Beschreibung: Bio-oil is a candidate renewable feedstock for hydrogen (H 2 ) production. In this work, n -butanol was chosen as a model compound representing alcohols in the bio-oil aqueous fraction. H 2 production from steam reforming of n -butanol was investigated in a fixed-bed reactor using commercial Ni/hydrotalcite catalyst. A plausible reaction pathway in presence of Ni was discussed. The rise in reforming temperature, space time and steam/carbon ratio in feed enhanced n -butanol conversion and H 2 yield. Reaction kinetics was studied in the chemical control regime (623-773 K). The reaction order with respect to n -butanol (one) and the activation energy (50 kJ/mol) were found.

Beschreibung: Attempts to perform Pasteurian resolution on epinephrine (or adrenaline) hydrogeno-tartrate always lead to limited enrichments in (-) epinephrine. Structural and thermal investigations are performed on the diastereomeric system to understand this behavior. These analyses revealed the existence of a (metastable) total solid solution between the two anhydrous diastereomeric salts. This solid solution is partially inhibited by the crystallization of a stable hydrate nevertheless its extension still prevents high enrichment by a single-step crystallization. Phase diagrams are proposed to illustrate this non-favored and non-predictable behavior.

Beschreibung: Near infrared spectrum analysis coupled with partial least squares regression can predict anaerobic digestion performances. Nonetheless, due to the complexity and diversity of organic matter, a detailed assessment of the effects of the composition of organic matter on biogas production remains a great challenge. Based on 275 samples representing a wide diversity of substrates, this paper discusses the use of the partial least square b coefficients to assess the effects of the involved molecules on the performances of anaerobic digestion processes. In particular, to accurately predict variables, there is a need to account for the whole near infrared spectrum. The characterization of organic matter involving proteins, carbohydrate and lipid contents, chemical demand in oxygen, biodegradability, methane yield and methane production kinetics data is thus demonstrated.

Beschreibung: The morphological and chemical changes in deciduous dentin produced by different conditioning protocols were evaluated in this in vitro study. Eighty primary dentin samples were divided into eight groups ( n  = 10): G1, acid etching; G2, self-etching adhesive; G3, G4, Er: YAG laser irradiation at 25.5 and 38.2 J cm −2 , respectively; 10 Hz and spray irrigation. Groups 5, 6, 7, and 8 were irradiated at previous densities, and then phosphoric acid or self-etching adhesive conditioning was applied. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were used to evaluate chemical and morphological changes. Paired t-test and One-way ANOVA were used for statistical analysis ( p  ≤ 0.05). All samples showed different morphology with specific characteristics according to the conditioning protocol. Changing element concentration values are expressed in atomic percent (at %). After conditioning, there were statistically significant differences ( p  ≤ 0.05) for p at% and Ca/P in all groups; highlighting the following additional findings by group: G1, G7, and G8 showed changes in all elements studied, G2 presented a decrease in C at% and increased Ca at%, G3 and G4 exhibited at% changes in C, trace elements and Ca. Furthermore, G5 showed at% changes in O and trace elements; while G6 changes were observed on C at%, O at% and trace elements at%. Dentin morphology and chemical composition varied in accordance with the conditioning protocol, with characteristics specific for each one that could have clinical implications for the retention and bond strength performance of adhesive materials. The most aggressive conditioning protocol according to mineral content reduction was phosphoric acid, whereas self-etching produced the least aggressive morphological changes, and Er:YAG laser irradiation enhanced deciduous dentin mineral structure.

Beschreibung: Experiments have been performed with upward pipe flow of nitrogen and water/Luviskol ® solutions with dynamic viscosities in the range of 0.001 – 7 Pa ∙ s. The intention of these experiments was to investigate, if empirical models from the literature are capable to predict the two-phase pressure drop with highly viscous liquids in e.g. vent lines behind polymerization reactors or for production applications like LDPE-reactors. By measuring the difference of the static pressure in a vertical pipe of 54.5 mm inner diameter across a test section with a length of 3.1 m the gradient of the friction pressure has been determined. Despite a careful execution and evaluation of the 87 experiments the frictional pressure gradients show some unexpected scatter. In case of slug flow even negative gradients have been found. Nevertheless, a comparison with 8 models selected from the literature show a sufficient accuracy for the models of Lockhart and Martinelli [13] with an extension by Chisholm [14], as well that of Claxton et al. [17] and of Friedel [1] for the measured two-phase flow data with highly viscous liquids, if the empirical parameters in the models are adapted to the new measurements.

Beschreibung: “ Nanhai I ” shipwreck of China Southern Song Dynasty is the oldest and the most integrally preserved shipwreck in the world. The related conservation and archeological research have caught great attention of different experts all over the world. In this study, different types of concretion covered on the surface of the ceramics in “ Nanhai I ” shipwreck were analyzed by X-ray diffractometer, micro-Raman spectrometer, and scanning electron microscope equipped with energy dispersive spectroscopy. Based on the analyses, we found that the grey concretion was mainly composed of quartz, aragonite, and calcite while the reddish concretion was mainly composed of pyrite and quartz. Our study indicated that the formation process of the grey concretion probably included the crystallization and transformation of aragonite, while the corrosion of iron implements and crystallization of pyrite were highly involved in the formation of reddish concretion. Concretion of ceramics in the “Nanhai I” shipwreck consisted two major parts. Formation of the grey part included crystallization and transformation of aragonite. Formation of pyrite framboids were involved in the formation of reddish part.

Beschreibung: Alcohols are widely used to reduce soot emission as alternative fuel for SI engines. 2-D soot distribution of alcohols/gasoline blends were studied in laminar diffusion flames by 2C-LII technique. The results showed that the soot volume fraction decrease with alcohols blending ratio significantly. At the same blending ratio, the soot reducing ability decreased with alcohol's carbon length, but the reducing effect for short chain alcohols, methanol and ethanol, deteriorated at high blending ratio while it remained constant for long chain alcohol, butanol. At the fixed oxygen content, the soot reducing ability of short chain alcohol is still higher than that of long chain alcohol, which inferred it is not only oxygen content but also molecular structure dominates the soot reducing ability.

Beschreibung: The solubility of malonic acid in five pure solvents and a binary solvent mixture was measured. Results reveal that the solubility increases with the temperature in the solvents studied. Different thermodynamic models were applied to correlate the solubility data in pure and binary solvents and were found to match well with the experimental data. Computational investigations were performed using Molecular Dynamic (MD) simulations. Results show that in pure solvents using alcohols, the (solute+solvent) interaction together with (solvent+solvent) interaction affect the solubility behavior; while in pure solvents of acetone and acetonitrile, the (solute+solvent) interaction is the key factor.

Beschreibung: Hydroxyapatite crystallization was performed within a batch type crystallizer both with and without tricarballylic acid used as an additive media. Initially, the crystals produced in pure media and in the presence of tricarballylic acid were analyzed using different types of characterization techniques such as XRD, SEM, TEM, BET and FTIR. Subsequently, the thermal degradation of the crystals obtained with and without tricarballylic acid media was accomplished in a thermal analyzer at temperatures from 30 to 1000 °C at rates of 5, 10 and 20 °C min −1 in an inert atmosphere. Experimental data was used to calculate the activation energies based on Kissinger, FWO, KAS and Starink kinetic models. The results revealed that tricarballylic acid was adsorbed onto the crystal surface, and it had significant effects on the crystal morphology, thermal degradation behavior and the average activation energy.

Beschreibung: The aim of this study was to assess the cleaning capacity of the octenidine hydrochloride (OCT) used as root canal irrigant by scanning electron microscopy (SEM) analysis. Sixty human unirradicular extracted teeth were randomly distributed in 6 groups ( n  = 10) according to irrigant solutions which were used during root canal preparation: G1, 0.1% OCT; G2, 2% chlorhexidine (CHX); G3, 2.5% sodium hypochlorite (NaOCl); G4, OCT + 17% ethylenediaminetetraacetic acid (EDTA); G5, 2.5% NaOCl + 17% EDTA and G6, distilled water. All specimens were instrumented with ProTaper system up to F4. Teeth were sectioned and prepared for SEM. The smear layer was evaluated using a 5-score system and the data were analyzed by Kruskal–Wallis and Dunn (α = 0.05). In all root canal thirds there was no significant difference between OCT, CHX, NaOCl, and water groups ( p  〉 .05), and these groups showed higher smear layer values than NaOCl + EDTA and OCT + EDTA groups ( p  〈 .05). There was no significant difference between NaOCl + EDTA and OCT + EDTA groups ( p  〉 .05). It was concluded that OCT used as a single root canal irrigant presented poor cleaning capacity and could be used in association with a final irrigation with EDTA to obtain smear layer removal. Octenidine could be used as root canal irrigant. However, it should be used with a final irrigation with EDTA to improve root canal cleaning.

Beschreibung: The mixing process in biogas plants is key to effectiveness. Unfortunately, difficulties at full scale mean that research must usually be performed at lab-scale and the results up-scaled. This study presents a scale-up strategy for the fluid flow in shear thinning, non-Newtonian fluids. Dimensional analysis was used to connect the influencing parameters (geom. dimensions, rot. speed, rheological properties) to key figures. By using the Reynolds and Hedström number, standards for adapting the rotational speed and rheological properties were defined as a function of the scale. A sliding-mesh-model was used for numerical simulations of a plant with a paddle agitator at two different scales. The scale-up approach leads to similar velocity fields, which result in equal normalized mixing times.

Beschreibung: The chemical compositions (organic and inorganic contents) and mechanical behaviors of the dentin of permanent and deciduous teeth were analyzed and compared using X-ray fluorescence spectrometry (µ-EDXRF) Fourier transform Raman spectroscopy (FT-Raman) and a microhardness test (HD). Healthy fresh human primary and permanent molars ( n  = 10) were selected, The buccal surfaces facing upwards were stabilized in an acrylic plate, flattened, polished, and submitted to the µ-EDXRF, FT-Raman, and HD analysis. The results of the analysis were subjected to ANOVAs and Mann-Whitney U /Student's t multiple comparisons tests. The data showed similar values for the dentin of the primary and permanent teeth in P content, organic content (amide I peak), inorganic content ( – 430 and 590), and microhardness, Nevertheless, Ca content and Ca/P weight ratio were higher, and the peak was lower in the dentin of the permanent teeth compared to primary teeth. It be concluded that despite permanent teeth showed more Ca element, both substrates showed similar behavior of chemical and physical properties. The dentine substrate of primary teeth presents the lowest Ca content and Ca/P weight ratio and the permanent human dentine showed the lowest peak.

Beschreibung: Most of amino acids, which are utilized as medical raw materials and food additives, show polymorphism. In order to improve the physical and chemical properties of the crystals, an effective method for polymorph control is required in the crystallization process. In this study, polymorph control of L-Phenylalanine in cooling crystallization by ultrasonic irradiation was investigated. L-Phenylalanine crystallizes into anhydrate and monohydrate form. Without irradiation, the mixture of monohydrate and anhydrate form was obtained. In contrast, the yield of monohydrate was increased by irradiation. In addition, the irradiation caused shortening of induction time. It was considered that the ultrasonic energy could supply the energy required for primary nucleation.

Beschreibung: Modification of activated carbon (AC) by basic ionic liquid, [Bmim]OH, was carried out.The surface functional groups of AC have changed evidently from the analysis of FTIR technology and Boehm titration. To argue the influence of functional group change on adsorption performance, the AC and modified activated carbon (MAC) was employed to remove methylene blue (MB). The results indicated that the adsorbance increased with the increase of initial concentration and lapse of contact time. The adsorption capability of AC was distinctly higher than that of MAC. From the analysis of kinetic studies, the pseudo-second-order kinetic model can well describe the adsorption process.