Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.423
Filtrar
1.
Waste Manag ; 105: 550-559, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32146416

RESUMO

In the South-Tyrol region (Italy), 46 gasifiers are currently operating and €200,000 are annually paid to dispose of as a waste 1300 tons of char. Therefore, there is a considerable interest in finding alternatives for the valorization of this solid by-product. The aim of this work is to assess the potential of char as energy source and to compare two scenarios. The first scenario considers the possibility of exploiting char in a dedicated burner integrated in the gasification plant. The second scenario assumes that all the char is collected from South-Tyrol and co-fired with biomass in an existing combustion-ORC plant. An economic analysis was performed evaluating the discounted payback time and both scenarios were modeled using Aspen Plus®. The results reveal that substantial savings in the operating costs of the plants can be achieved. In the first scenario the owners of the gasification plants could save from 50% to 94% of the char disposal costs with a payback time ranging between 3 and 7 years. In the second scenario, the owner of the plant could save approximately €235 k per year with a payback time of approximately 7 years. The present study provides a basis for further techno-economic studies on char combustion. The results can be helpful for the owners of the gasification plants in determining the most cost-effective way to dispose char and to avoid disposing it of as a waste. Furthermore, it is demonstrated how char could be used as a renewable fuel, with better performance than raw biomass.


Assuntos
Fontes Geradoras de Energia , Biomassa , Análise Custo-Benefício , Itália , Fenômenos Físicos
3.
Bioresour Technol ; 304: 123018, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32087547

RESUMO

Adoption of circular practices within environmental management is gaining worldwide recognition owing to rapid resource depletion and detrimental effects of climate change. The present study therefore attempted to ascertain the linkages between circular economy (CE) and sustainable development (SD) by examining the role of renewable energy (RE) and waste management (WM) sectors in CE combined with policy setup and enabling frameworks boosting the influx of circularity principles in the Indian context. Results revealed that research dedicated towards energy recovery from waste in India lacks integration with SD. Findings also revealed that although India is extremely dedicated towards attainment of the SDGs, penetration of CE principles within administration requires considerable efforts especially since WM regulations for municipal, plastic and e-waste lack alignment with CE principles. Integration of WM and RE policies under an umbrella CE policy would provide further impetus to the attainment of circularity and SD within the Indian economy.


Assuntos
Gerenciamento de Resíduos , Mudança Climática , Índia , Fenômenos Físicos , Energia Renovável , Resíduos Sólidos
4.
Nature ; 578(7795): 369-370, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32076217
6.
Nature ; 578(7793): 44-45, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32025006
8.
Bioresour Technol ; 303: 122951, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32058908

RESUMO

The present study aimed to employ energy efficient chemo thermal coupled sonic homogenization (CTSH) to obtain VFA from marine macroalgal hydrolysate, (Ulva fasciata). At first, chemo thermal homogenization (CTH) was applied on macroalgal biomass by adjusting the temperature, pH and treatment time from 60 to 90 â„ƒ, 4-7 and 0-60 min, respectively. A higher organic matter solubilisation of 11.81% was obtained at an optimum pH of 6 at a temperature of 80 â„ƒ with 40 min of homogenization time. The results of CTSH implied that a higher organic matter solubilization of 26.4% was achieved by combined CTSH (sonic power & treatment time - 140 W & 14 min treatment time). CTSH considerably doubles the liquefaction in comparison with CTH. Based on OMS grouping, achieving 25% was sufficient for VFA production (2172.09 mg/L) and considered as economically feasible with net cost of 97.17 USD/ton of macroalgae.


Assuntos
Alga Marinha , Ulva , Biomassa , Ácidos Graxos Voláteis , Fermentação , Fenômenos Físicos
9.
Magn Reson Chem ; 58(2): 163-169, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31671221

RESUMO

The chemical shift difference, Δσ, between the methylene and hydroxyl protons in the high resolution 1 H nuclear magnetic resonance spectrum of ethylene glycol is shown to be pressure dependent. The equilibrium Δσ values for ethylene glycol are reported as a function of temperature and pressure between ambient conditions, 323 K and 2 kbar, respectively. This surface is used along with Δσ values measured in response to a rapid pressure increase to calculate a temperature rise that is used to infer a temperature change for water that is consistent with theoretical estimates. This work implies that compression heating and decompression cooling are not significant enough to interfere with pressure induced protein folding studies.


Assuntos
Temperatura Baixa , Etilenoglicol/química , Temperatura Alta , Fenômenos Físicos , Pressão , Espectroscopia de Prótons por Ressonância Magnética
10.
Environ Monit Assess ; 192(1): 3, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31797152

RESUMO

In this study, new analytical solutions were developed for 2D and 3D steady-state water seepage through dams with nonsymmetric boundary conditions. The nonsymmetric boundary conditions for the 2D cases were created with different unit step functions on a part and/or parts of the right boundary of dam plane. Six cases were investigated in 2D, where a constant hydraulic head is applied at the left boundary of the dam plane and rectangular, ramp, triangular, trapezoidal, tunnel, and piecewise rectangular distributions of hydraulic head are applied at the right boundary of the dam plane. Then, a 3D case with a constant hydraulic head at the upstream and a linearly distributed hydraulic head at the downstream of the dam was investigated. Subsequently, the performance of proposed analytical solutions was examined by comparison with numerical finite difference modeling. The results demonstrate reasonable accuracy of the developed equations. The developed analytical solutions can be utilized as a benchmark to verify numerical models with similar boundary conditions.


Assuntos
Modelos Teóricos , Movimentos da Água , Monitoramento Ambiental , Água Subterrânea , Fenômenos Físicos
11.
Science ; 366(6470): 1206, 2019 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-31806805
13.
Science ; 366(6471): 1312-1313, 2019 12 13.
Artigo em Inglês | MEDLINE | ID: mdl-31831657
14.
Nature ; 576(7787): 390-392, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31853070
15.
Am J Orthod Dentofacial Orthop ; 156(5): 582-592, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31677666

RESUMO

INTRODUCTION: There is a high degree of uncertainty regarding the appropriate force level that should be applied during orthodontic tooth movement (OTM). As a result, orthodontic treatments may take longer than necessary, leading to unwanted side effects. This review aimed to identify an optimal force range with the rate of OTM as the primary outcome. External apical root resorption and pain were evaluated as secondary outcomes, and the influence of growth was examined. METHODS: Five electronic databases were searched (MEDLINE [via PubMed], Embase [via OVID], Cochrane Library, CINAHL, and Web of Science) with no publication date or language restrictions. Inclusion eligibility screening, quality assessment, and data extraction were performed by 3 investigators. Each retrieved record was assessed by 2 observers independently. Only randomized controlled trials and randomized split-mouth studies were included. RESULTS: A total of 12 articles satisfied the inclusion criteria-two randomized controlled trials and 10 randomized split-mouth studies. Only 1 study showed a low risk of bias, whereas the remaining 11 were unclear. The qualitative analysis showed that forces between 50 cN and 250 cN produced a similar OTM rate; forces >250 cN yielded a slightly higher rate but were accompanied by adverse effects. Because of considerable heterogeneity in methodology, clinical diversity with varying forces between 18 cN and 360 cN, and poor statistical reporting, a meta-analysis was deemed inappropriate. CONCLUSIONS: Forces between 50 cN and 100 cN seem optimal for OTM, patient comfort and potentially exhibit fewer side effects. Nevertheless, careful data interpretation is necessary because of the lack of strong evidence. Protocol registration: PROSPERO CRD42016039985.


Assuntos
Braquetes Ortodônticos , Técnicas de Movimentação Dentária , Humanos , Boca , Aparelhos Ortodônticos Fixos , Fenômenos Físicos , Ensaios Clínicos Controlados Aleatórios como Assunto
16.
Pharm Res ; 36(12): 183, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31741058

RESUMO

Research conducted in microgravity conditions has the potential to yield new therapeutics, as advances can be achieved in the absence of phenomena such as sedimentation, hydrostatic pressure and thermally-induced convection. The outcomes of such studies can significantly contribute to many scientific and technological fields, including drug discovery. This article reviews the existing traditional microgravity platforms as well as emerging ideas for enabling microgravity research focusing on SpacePharma's innovative autonomous remote-controlled microgravity labs that can be launched to space aboard nanosatellites to perform drug research in orbit. The scientific literature is reviewed and examples of life science fields that have benefited from studies in microgravity conditions are given. These include the use of microgravity environment for chemical applications (protein crystallization, drug polymorphism, self-assembly of biomolecules), pharmaceutical studies (microencapsulation, drug delivery systems, behavior and stability of colloidal formulations, antibiotic drug resistance), and biological research, including accelerated models for aging, investigation of bacterial virulence , tissue engineering using organ-on-chips in space, enhanced stem cells proliferation and differentiation.


Assuntos
Simulação de Ausência de Peso/instrumentação , Simulação de Ausência de Peso/métodos , Ausência de Peso , Fatores Etários , Diferenciação Celular , Linhagem Celular , Proliferação de Células , Cristalização/instrumentação , Cristalização/métodos , Dimerização , Composição de Medicamentos/instrumentação , Composição de Medicamentos/métodos , Sistemas de Liberação de Medicamentos/instrumentação , Sistemas de Liberação de Medicamentos/métodos , Descoberta de Drogas/instrumentação , Descoberta de Drogas/métodos , Resistência Microbiana a Medicamentos , Humanos , Microfluídica/instrumentação , Microfluídica/métodos , Pesquisa Farmacêutica/instrumentação , Pesquisa Farmacêutica/métodos , Fenômenos Físicos , Proteínas/química , Voo Espacial , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos
17.
Adv Exp Med Biol ; 1192: 331-340, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31705503

RESUMO

The biopsychosocial approach is a model of eclecticism, which consists of multidisciplinary academic fields, reacting against the "neuroscientification" of psychiatry. The biopsychosocial approach was proposed by George Engel following Adolf Meyer's psychobiological and Roy R. Ginker's eclectic approach to psychiatry. Although the use of the biopsychosocial approach is increasing, it has several limitations: First, specific practices cannot be guided by the biopsychosocial approach because it is considered to be "boundless psychiatry." Second, unlike an initial intention, the symptomatic use of psychotropic medications may be justified by the biopsychosocial approach. Third, the economic forces to enhance biological psychiatry cannot be hindered by the biopsychosocial approach. Hence, to overcome the limitations of the current biopsychosocial approach, potential new paradigms including evolutionary psychiatry, pragmatism, integrationism, and pluralism have been proposed. Above all, Eric Kandel presented the link between neuroscience and psychiatry from the perspective of integrationism. In accordance with integrationism and/or pluralism, based on the paradigm shift of the theoretical construct from chemical imbalance to dysfunctional circuit, next-generation treatments for mental disorders have been proposed by Thomas Insel. Thus, a more integrated biopsychosocial approach to managing psychiatric disorders including schizophrenia and panic disorder may be proposed.


Assuntos
Transtornos Mentais , Neurociências , Psiquiatria , Humanos , Fenômenos Físicos , Esquizofrenia
18.
Artigo em Inglês | MEDLINE | ID: mdl-31575024

RESUMO

It is of great significance to deal with the relationship between external factors and the water-energy-food internal system for China's sustainable development. This paper takes China as the research object, uses the system dynamics method to construct a model for China's water-energy-food system, and introduces the "two-child" policy and trade friction as the scenario parameters for simulation. The main results of scenario simulation can be summarized as the following three points. In terms of water, the trade friction will hinder China's industrial water consumption into a low-consumption stage. In terms of energy, both the trade friction and the "two-child" policy, will not change the increasing trend of energy demand. In terms of food, if there is strong response to the "two-child" policy, there will be insufficient food inventory under the current capacity and import ratio. In short, this paper takes the sustainable development of water-energy-food as a starting point and puts forward policy suggestions on the comprehensive formulation of policies.


Assuntos
Conservação de Recursos Energéticos , Abastecimento de Alimentos , Desenvolvimento Sustentável , Abastecimento de Água , China , Alimentos , Indústrias , Fenômenos Físicos , Água
19.
Science ; 365(6460): 1378-1379, 2019 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-31604256
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA