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101.
102.
Vehicle and crew scheduling for urban bus lines 总被引:1,自引:0,他引:1
Maikol M. Rodrigues Cid C. de Souza Arnaldo V. Moura 《European Journal of Operational Research》2006,170(3):844-862
A solution to the urban transportation problem is given by vehicle and crew schedules. These schedules must meet the passenger demand and satisfy technical and contractual restrictions stemming from the daily operation of the lines, while optimizing some measure of operational cost. This work describes a computational tool developed to solve the urban transportation problem in the large metropolitan area of São Paulo, Brazil. The techniques used are based on integer programming models coupled with heuristics. The former produces good feasible solutions, and the latter improves the quality of the final solutions. While the operational and labor restrictions are specific to the city of São Paulo, the same ideas can inspire similar approaches for solving the urban transportation problem arising in other metropolitan areas. 相似文献
103.
Partial synchronization (PaS) on regular networks with a few non-local couplings are studied. The criterion that PaS can emerge in any given network and some relevant phenomena about Lyapunov exponents are found. Theoretical and numerical analysis show that the non-local coupling is the key mechanism of the emergence of PaS. 相似文献
104.
进行了拖拉机田间作业故障跟踪试验 ,得到了拖拉机现场使用的故障数据 ,用非齐次泊松过程建立了拖拉机故障过程的数学模型 ,并用神经网络方法给出了模型的参数估计 ,讨论了拖拉机故障过程的改善与劣化与故障强度函数的关系 ,得到了拖拉机使用初期的故障强度曲线 ,给出了平均故障间隔时间的估计值 . 相似文献
105.
M. J. T. Carrondo J. P. S. G. Crespo M. J. Moura 《Applied biochemistry and biotechnology》1988,17(1-3):295-312
The kinetics ofP. acidipropionici (ATCC25562), a xylose-utilizing rumen microorganism, was studied to assess its use for propionic acid production from wood
hydrolyzates.
Propionic acid has been shown to have a stronger inhibitory effect than acetic acid, with the undissociated acid form being
responsible for the majority of the inhibitory effect. Thus, in batch tests with pH controlled at 6.0, the propionic acid
concentration reaches 25 g/L and the acetic acid 7 g/L. Xylose uptake rate is dependent on the specific growth rate and glucose
concentration.
An immobilized cell columnar reactor at very high product yields (80%) proved adequate for propionic production. At cell concentrations
of 95 g/L with high product concentration, volumetric productivities of 2.7 g/L·h were obtained in ultrafiltration cell recycle
systems. 相似文献
106.
An investigation about the thermal degradation of acetylsalicylic acid (ASA) is performed. It is verified that the thermal degradation of ASA produces not only salicylic acid (SA) and acetic acid (AA) as products but also an ASA polymer, which is transparent and solid. And also verified that the temperature in which the polymer is obtained influences its physical consistence (solid or semi-solid). Furthermore, the ASA polymer is very stable from a thermic point of view, as verified by TG and DSC analysis. X-ray diffraction patterns obtained for the ASA polymer show that it exhibits a low crystallinity. 相似文献
107.
B. H. Huynh I. Moura A. R. Lino J. J. G. Moura J. Legall 《Hyperfine Interactions》1988,42(1-4):905-908
Mössbauer, EPR, and biochemical techniques were used to characterize two dissimilatory sulfite reductases: desulforubidin fromDesulfovibrio baculatus strain DSM 1743 and desulfoviridin fromDesulfovibrio gigas. For each molecule of desulforubidin, there are two sirohemes and four [4Fe?4S] clusters. The [4Fe?4S] clusters are in the diamagnetic 2+ oxidation state. The sirohemes are high-spin ferric (S=5/2) and each siroheme is exchanged-coupled to a [4Fe?4S]2+ cluster. Such an exchange-coupled siroheme-[4Fe?4S] unit has also been found in the assimilatory sulfite reductase fromEscherichia coli/1/ and in a low-molecular weight sulfite reductase fromDesulfovibrio vulgaris/2/. For each molecule of defulfoviridin, there are two tetrahydroporphyrin groups and four [4Fe?4S]2+ clusters. To our surprise, we discovered that about 80% of the tetrahydroporphyrin groups, however, do not bind iron. 相似文献
108.
Carlos Roberto Ferreira Junior Fabrício Nunes Tanaka Adriel Bortolin Márcia Regina de Moura Fauze Ahmad Aouada 《Journal of Thermal Analysis and Calorimetry》2018,131(3):2205-2212
The use of fertilizer and water availability are essential factors limiting the agricultural production. The controlled release technology is very promising because it allows the maintenance of fertilizer concentrations within an ideal range avoiding inefficiency and toxicity problems, minimizing the environmental impacts and improving their efficiency. In this context, the nanostructured hydrogels appear as a possible carrier vehicle for these controlled release systems due to their inherent properties, such as biodegradability, low toxicity, and cost, rapid absorption and desorption controlled capacity of water and solutes. In this work, we performed the synthesis of nanostructured hydrogels based on poly(methacrylic acid) (PMAA)/Cloisite-Na+ via free radical polymerization. SEM images indicated a similarity in the basic structure of all nanocomposites. The porous diameter of the hydrogels increased with increasing of nanoclay content. EDS analysis showed the ions belonging to nanoclay present in the nanocomposites, confirming the formation of true nanocomposites. TG–DTG and DSC techniques confirmed an improvement in the thermal stability of nanocomposites caused by the addition of nanoclay. For instance, the degradation initial temperature of the hydrogel was increased from 198.5 to 203.5 °C, and inversely, the degradation rate of the 2° thermal event was decreased from 0.694 to 0.472% min °C?1, when the nanoclay was increased from 0 to 20 mass/%. Moreover, the controlled release investigation showed an improvement in the release time and quantity of the fertilizer released with nanoclay content. This result is very required for this specific application. 相似文献
109.
Antonio?S.?AraujoEmail author Antonio?O.?S.?Silva Marcelo?J.?B.?Souza Ana?C.?S.?L.?S.?Coutinho Joana?M.?F.?B.?Aquino José?A.?Moura Anne?M.?G.?Pedrosa 《Adsorption》2005,11(2):159-165
In this work the acid properties of a series of HZSM-12 zeolites with different Si/Al ratio were studied. The ZSM-12 crystals
were synthesized by the hydrothermal method starting from a gel with the following molar composition: 20MTEA:10Na2O:x Al2O3:100SiO2:2000H2O, with x = 0.50, 0.67, 1, 1.25 and 2, respectively. The gels were crystallized at 140∘C for 6 days, then washed, dried and calcined to remove the MTEA template. The samples were ion-exchanged with an ammonium
chloride solution and calcined again to obtain the zeolites in the acid form. The materials thus obtained were characterized
by XRD, SEM, BET, TG and n-butylamine adsorption. The Si/Al ratio in the reaction mixture affects the amount of zeolite produced and the size of the
particles. The XRD analysis indicated that the ZSM-12 zeolite crystallizes in a pure form only with Si/Al ratio above 33.
The SEM analysis showed the presence of crystallites with very well defined prismatic shapes. The removal of the MTEA of the
pores of the ZSM-12 by TG indicated that there are two kinds of internal sites occupied by MTEA inside the structure. The
BET area of the ZSM-12 decreases proportionally with the crystallinity of materials. The desorption of n-butylamine showed
that the acid site density is proportional to aluminum content, but the Si/Al ratio shows little influence on the relative
strengths of these sites. 相似文献
110.
Moura Edmilson M. Terra Vilma R. Siebald Helmuth G. L. de Lima Geraldo M. Paim Lilian A. Dias Fabrícia M. 《Transition Metal Chemistry》2003,28(4):437-442
A series of heterobimetallic complexes containing Ru–Sn bonds, of general formula [RuCp(L)2SnX2Y] [L = PPh3, 1/2 dppe = 1,2-bis(diphenylphosphino)ethane; X, Y = F, Cl and Br], was prepared and studied by elemental analysis, 119Sn-Mössbauer spectroscopy, i.r. and 1H-, 13C-, 19F-, 31P- and 119Sn-n.m.r. spectroscopy. 119Sn-Mössbauer studies allowed determination of the coordination number of the SnII center as well as the group electronegativity of the organometallic fragment [RuCp(L)2]+. These results, supported by multinuclear n.m.r. data suggested that the electronic charge distribution between the RuII and SnII centers are strongly dependant upon the nature of L and the electronegativity of X and Y. 相似文献