573 research outputs found
Scope economies between indiscriminate and selective urban solid waste collection
Recycling is one possible option within municipal solid waste (MSW) management to
deal with the growing quantities of MSW produced. Only a few scholars have analysed
the costs of this service and asked the question whether municipal solid waste
management service utilities benefit from providing waste disposal and recycling
services jointly. This dissertation tries to answer this question in the Portuguese context.
In other words, it tries to find whether there are economies of scope in the Portuguese
municipal solid waste management market between waste collection and disposal and
recycling services.
To answer the question, this study estimates a cost function of the municipal solid waste
collection and disposal and recycling services in Portugal. Using a panel of 260
Portuguese retail municipal solid waste management service providers observed from
2001 to 2015, a multi-output translog cost function is estimated. The index value for
scope economies is -0.27, meaning diseconomies of scope have been found.A reciclagem é uma opção possível na gestão de residuos sólidos urbanos para lidar com
a crescente quantidade deste tipo de resíduos que é produzida. Não existem muitos
Estudos que tenham analisado este serviço e perguntado se as entidades gestoras de
resíduos sólidos urbanos beneficiam do fornecimento simultâneo dos serviços de recolha
de lixo e de reciclagem. Esta dissertação procura responder a essa questão no contexto
português. Por outras palavras, ela tenta descobrir se existem economias de gama na
gestão de resíduos sólidos urbanos no mercado português entre a recolha de resíduos e os
serviços de reciclagem.
Para responder à questão, este estudo estima uma função de custo para os serviços de
recolha de resíduos sólidos urbanos e de reciclagem em Portugal. Usando um painel de
260 entidades gestoras de serviços de gestão de resíduos sólidos urbanos observadas de
2011 a 2015, estima-se uma função de custos multi-produto translog. O índice de
economias de gama é de -0.27, significando que existem deseconomias de gama
Triaquabis{μ-N-[N-(4-methoxy-2-oxidobenzylidene)glycyl]glycinato(3−)}cadmium(II)dicopper(II) dihydrate
In the title compound, [CdCu2(C12H11N2O5)2(H2O)3]·2H2O, the CuII atoms are in a square plane of N2O2 atoms contributed by the tetradentate Schiff base trianion. The CuII atoms are coordinated by one phenolate O atom, one imine N atom, one amido N atom and one carboxylate O atom. The CdII atom is connected via the carboxylate groups, forming a heterotrinuclear CuII–CdII–CuII system. The CdII atom is seven-coordinate in a pentagonal-bipyramidal geometry with four O atoms from two carboxylate groups and three aqua ligands. The heterotrinuclear molecules are linked to the uncoordinated water molecules by O—H⋯O hydrogen bonds into a three-dimensional framework
Hexaaquamagnesium(II) bis{[N-(4-methoxy-2-oxidobenzylidene)glycylglycinato(3−)]cuprate(II)} hexahydrate
In the title complex, [Mg(H2O)6][Cu(C12H11N2O5)]2·6H2O, the CuII atoms lie at the center of the square plane of triple negatively charged O,N,N′,O′-tetradentate Schiff base ligands, which are coordinated by one phenolate O atom, one imine N atom, one deprotonated amide N atom and one carboxylate O atom. The MgII center, which sits on an inversion center, is coordinated by six aqua ligands and exhibits a slightly distorted octahedral conformation. The asymmetric unit consists of an [N-(4-methoxy-2-oxidobenzylidene)glycylglycinato]cuprate(II) anion, one half of an [Mg(H2O)6]2+ cation and three free water molecules. The cations and anions form columns by O—H⋯O hydrogen bonds
Integrated dynamic analysis of a spar floating wind turbine with a hydraulic drivetrain
publishedVersionPaid open acces
Hexaaquacobalt(II) bis{[N-(4-methoxy-2-oxidobenzylidene)glycylglycinato]nickel(II)} hexahydrate
In the title compound, [Co(H2O)6][Ni(C12H11N2O5)]2·6H2O, the NiII atom has a nearly square-planar coordination with two N and two O atoms of the N-(4-methoxy-2-oxidobenzylidene)glycylglycinate Schiff base ligand (L
3−). The CoII atom sits on an inversion center and is coordinated to six aqua ligands in a slightly distorted octahedral geometry. The [Co(H2O)6]2+ cations and [NiL]− anions form columns along the a axis by O—H⋯O hydrogen bonds. Additional hydrogen bonds between the uncoordinated and coordinated water molecules help to consolidate the crystal packing
Direct Regularization from Co-Registered Anatomical Images for MRI-Guided Near-Infrared Spectral Tomographic Image Reconstruction
Combining anatomical information from high resolution imaging modalities to guide near-infrared spectral tomography (NIRST) is an efficient strategy for improving the quality of the reconstructed spectral images. A new approach for incorporating image information directly into the inversion matrix regularization was examined using Direct Regularization from Images (DRI), which encodes the gray-scale data into the NIRST image reconstruction problem. This process has the benefit of eliminating user intervention such as image segmentation of distinct regions. Specifically, the Dynamic Contrast Enhanced Magnetic Resonance (DCE-MR) image intensity value differences within the anatomical image were used to implement an exponentially-weighted regularization function between the image pixels. The algorithm was validated using simulated reconstructions with noise, and the results showed that spatial resolution and robustness of the reconstructed images were significantly improved by appropriate choice of the regularization weight parameters. The proposed approach was also tested on in vivo breast data acquired in a recent clinical trial combining NIRST / MRI for cancer tumor characterization. Relative to the standard “no priors” diffuse recovery, the contrast of the tumor to the normal surrounding tissue increased from 2.4 to 3.6, and the difference between the tumor size segmented from DCE-MR images and reconstructed optical images decreased from 18% to 6%, while there was an overall decrease in surface artifacts
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