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81.
Maximiliano Melnichuk Diego J. Cuscueta Nicolas Silin 《International Journal of Hydrogen Energy》2017,42(24):15799-15807
Volume expansion of hydrogen absorbing materials, together with inter-particle friction can cause tension accumulation in hydride containers during absorption. When hydride particles absorb hydrogen there is an important volume increase, in the order of 25%. Particles have to accommodate to the container geometry but this movement is opposed by inter-particle friction. Under certain conditions tensions can build up, compromising the mechanical integrity of the container. This phenomenon needs to be addressed at the design stage to avoid mechanical failure of the container.Flow behavior of powder materials is a relevant technological field, usually addressed by means of qualitative or quantitative flowability measuring devices. The rotating drum technique, while mainly qualitative, is well established and can be modified into a completely sealed unit. To determine the flowability of a hydride under different activation stages and hydrogen content levels we developed a rotating drum device that can be pressurized with hydrogen or depressurized. We report particle size evolution and flowability measurements of a hydrogen absorbing material (LaNi5) at different stages of activation for both absorbed and desorbed states. The results of the present study show that the flowability of LaNi5 in more dependent on the degree of activation of the sample than on hydrogen absorption state. 相似文献
82.
Bromelain is the denomination given to the group of endoproteases obtained from members of Bromeliacea family. These enzymes have a wide range of proven applications and have been an object of study for worldwide researchers for decades. Over the years, several different downstream processes were studied in order to determine which technique would be worthwhile to be implemented in Brazil and provide the national market with such product. The objective of the present study is to relate the main studies in Brazil that has proven that bromelain purification can be cost-effective, in addition to the well-known benefits owned by such enzymes, and highlight the applications that create their market potential in the Brazilian market. 相似文献
83.
Giuseppe Espa Danila Filipponi Diego Giuliani Davide Piacentino 《Papers in Regional Science》2014,93(Z1):S113-S135
In this paper, spatial shift‐share decomposition is analysed when applied to Italian data on regional business change at plant level, over the period 2004–2009. A new type of spatial decomposition, which looks more effectively at neighbourhood influence, is introduced here. Notable results emerge from the empirical investigation. First, it can be seen that the spatial level of aggregation greatly affects results. Second, evidence of neighbourhood advantage in the Southern NUTS 3 regions is found, together with opposite results for the Central‐Northern NUTS 3 regions. Finally, evidence of positive industrial mix effects is only found in Central‐Northern Italy. 相似文献
84.
Optical and Structural Properties of ZnO and ZnO:Cd Particles Grown by the Hydrothermal Method
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Diego A. Guzmán‐Embús Maria F. Vargas‐Charry Carlos Vargas‐Hernández 《Journal of the American Ceramic Society》2015,98(5):1498-1505
Here, we examine the structural, vibrational, optical, and morphological properties of ZnO particles synthesized by the hydrothermal method, incorporating cadmium at different concentrations through the molar ratio Rm = Cd+2/Zn+2 and a thermal treatment at 500°C. The X‐ray diffraction results demonstrated the high crystallinity of the ZnO compound with a wurtzite‐type hexagonal structure. The Raman scattering spectra demonstrated that the ZnO vibrational modes occur in the region between 200 and 1300 cm?1, which is associated with different vibrational configurations characteristic of the ZnO molecule: E2(Low), E2(M), A1(TO) E1(TO), 2B1(High), E2(High), and TA + LO. The modes that were most affected by the incorporation of Cd2+ were those assigned to 2E2(Low), E2(M), and 2B1(High), and this effect was associated with a greater displacement of Zn2+ ions. The optical study showed a reduction in the band gap and a decrease in the crystalline quality due to the substitution of Cd2+ in the ZnO lattice. Cadmium incorporation affected the morphology of the ZnO:Cd particles, changing the lengths and diameters of the ZnO rods; when the Cd concentration was increased, the ZnO rods shortened, forming coin‐type hexagonal structures. 相似文献
85.
In this study, polypropylene (PP) composites reinforced with short glass fibers (GF) and exfoliated graphite nanoplatelets were obtained by melt compounding followed by injection molding. Morphological observations and quasi‐static tensile tests were carried out in order to investigate how the morphology and the mechanical properties of the composites were affected by the combined effect of two fillers of rather different size scales (i.e., micro‐ and nanoscale). The results indicate that the dispersion of the nanofiller in the PP matrix promoted the formation of a stronger interface between the matrix and GF, as indicated by the increase of the interfacial shear strength determined by the single‐fiber microdebonding test. Concurrently, a significant improvement of the tensile modulus and impact strength of the composites was observed, with small changes in the processability of hybrid composites compared to that of GF composites, as confirmed by rheological measurements. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41682. 相似文献
86.
Polycarbonate‐based composites reinforced by in situ polytetrafluoroethylene fibrillation: Preparation,thermal and rheological behavior
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Diego Antonioli Katia Sparnacci Michele Laus Luca Boarino Maria Cristina Righetti 《应用聚合物科学杂志》2015,132(32)
Fibrillar reinforced composites of polytetrafluoroethylene (PTFE) and polycarbonate (PC) were prepared by in situ fibrillation of PTFE into PC matrix using twin screw extruder. Different samples were obtained by varying the relative ratio between PC and PTFE. The rheological properties of the PC/PTFE composites were found to depend on concentration of the PTFE fibrils. The melt strength analysis in nonisothermal conditions was also studied. The increase in force and decrease in drawability with increasing the PTFE content are associated with the PTFE fibrils formed in situ during the thermomechanical process in twin screw extruder. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42401. 相似文献
87.
In this paper we have represented the economic, environmental and territorial transformation of Metaponto district (southern Italy) generated by the land reform since 1950. The coastal area, once inhospitable and unproductive, through land reform has become a point of development for the entire Basilicata Region. The intensive model of economic development applied to agriculture and tourism today represents the main critical points of high environmental impact. In particular, the great human pressure exerted by economic activities has led to an insufficient capacity of water purification systems in the area and such criticism is amplified in the summer mainly for seaside tourism. In this study we have measured the environmental load exerted on the territory and we have estimated the human pressure on the district in the year 2030 and made proposals for amendments to current patterns of development in the agricultural and tourist sectors. 相似文献
88.
Metformin Reduces Lipogenesis Markers in Obese Mice Fed a Low-Carbohydrate and High-Fat Diet
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Karla Nayara de Oliveira Santana Deborah Farias Lelis Keila Lopes Mendes Jamille Fernandes Lula Alanna Fernandes Paraíso João Marcus Oliveira Andrade John David Feltenberger Junio Cota Diego Vicente da Costa Alfredo Mauricio Batista de Paula André Luiz Sena Guimarães Sérgio Henrique Sousa Santos 《Lipids》2016,51(12):1375-1384
Lipogenesis is the process by which fatty acids are synthesized. In metabolic syndrome, an insulin resistant state along with high plasma levels of free fatty acids (FFA) and hyperglycemia may contribute to the lipogenic process. The aim of the present study was to investigate the effects of oral administration of metformin on the expression of lipogenic genes and glycemic profile in mice fed with low‐carbohydrate high‐fat diet by evaluating their metabolic profile. SWISS male mice were divided into 4 groups (N = 7) that were fed with standard (ST), standard plus metformin (ST + MET), low‐carbohydrate high‐fat diet (LCHFD) and low‐carbohydrate high‐fat diet plus metformin (LCHFD + MET) (100 mg kg?1 diet) diets respectively. Food intake, body weight and blood parameters, such as glucose tolerance, insulin sensitivity, glucose, HDL‐c, total cholesterol, triglycerides, ASL and ALT levels were assessed. Histological analyses were performed on hematoxylin and eosin‐stained epididymal adipose tissue histological specimens. The expression levels of peroxisome proliferator‐activated receptor (PPARγ), sterol regulatory element‐binding protein 1 (SREBP1), fatty acid synthase (FAS) and acetyl‐CoA carboxylase (ACC), were assessed by RT‐PCR. This study showed that metformin decreased adipocyte area, body weight and food consumption in obese animals when compared to the standard group. Furthermore, the expression of lipogenic markers in adipose tissue were diminished in obese animals treated with metformin. This data showed that oral administration of metformin improved glucose and lipid metabolic parameters in white adipose tissue by reducing the expression of lipogenesis markers, suggesting an important clinical application of MET in treating obesity‐related diseases in metabolic syndrome. 相似文献
89.
Massimo Lorusso Alberta Aversa Diego Manfredi Flaviana Calignano Elisa Paola Ambrosio Daniele Ugues Matteo Pavese 《Journal of Materials Engineering and Performance》2016,25(8):3152-3160
Direct metal laser sintering (DMLS) is an additive manufacturing technique for the production of parts with complex geometry and it is especially appropriate for structural applications in aircraft and automotive industries. Aluminum-based metal matrix composites (MMCs) are promising materials for these applications because they are lightweight, ductile, and have a good strength-to-weight ratio This paper presents an investigation of microstructure, hardness, and tribological properties of AlSi10Mg alloy and AlSi10Mg alloy/TiB2 composites prepared by DMLS. MMCs were realized with two different compositions: 10% wt. of microsize TiB2, 1% wt. of nanosize TiB2. Wear tests were performed using a pin-on-disk apparatus on the prepared samples. Performances of AlSi10Mg samples manufactured by DMLS were also compared with the results obtained on AlSi10Mg alloy samples made by casting. It was found that the composites displayed a lower coefficient of friction (COF), but in the case of microsize TiB2 reinforcement the wear rate was higher than with nanosize reinforcements and aluminum alloy without reinforcement. AlSi10Mg obtained by DMLS showed a higher COF than AlSi10Mg obtained by casting, but the wear rate was higher in the latter case. 相似文献
90.