Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Ind Eng Chem Res ; 63(32): 14137-14147, 2024 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-39156967

RESUMO

Adsorption is at the heart of many processes from gas separation to cooling. The design of adsorption-based processes requires equilibrium adsorption properties. However, data for adsorption equilibria are limited, and therefore, a model is desirable that uses as little data as possible for its parametrization, while allowing for data interpolation or even extrapolation. This work presents a physics-based model for adsorption isotherms and other equilibrium adsorption properties. The model is based on one-dimensional classical density functional theory (1D-DFT) and the perturbed-chain statistical associating fluid theory (PC-SAFT). The physical processes inside the pores are considered in a thermodynamically consistent approach that is computationally efficient. Once parametrized with a single isotherm, the model is able to extrapolate to other temperatures and outperforms the extrapolation capabilities of state-of-the-art models, such as the empirical isotherm models from Langmuir or Toth. Furthermore, standard combining rules can be used to transfer parameters adjusted to an adsorbent/fluid pair to other fluids. These features are demonstrated for the adsorption of N2, CH4, and CO2 in metal-organic frameworks. Thereby, the presented model can calculate temperature-dependent isotherms for various fluids by using data limited to a single isotherm as input.

2.
Sports (Basel) ; 10(5)2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35622483

RESUMO

Two methods for challenging the musculoskeletal and nervous systems to better exploit the stretch-shortening cycle (SSC) mechanism during plyometric training are reactive strength exercises and accentuated eccentric loading (AEL). Combining repetitive, reactive jumping with AEL poses a novel approach, in which the effects of both methods may be combined to elicit a unique stimulus. This study compared kinematic, kinetic, and electromyographic variables between a control (CON1) and two AEL conditions (AEL2 and AEL3). Additionally, non-reactive and reactive jumps performed within these sets were compared. Participants performed two sets of six countermovement jumps (CMJ) under each loading condition. AEL3 had moderate to large positive effects (es) on peak and mean eccentric force (es = 1.1, 0.8, respectively; both p < 0.01), and eccentric loading rate (es = 0.8, p < 0.01), but no effect on concentric variables or muscle activation intensity. The effects of AEL2 were similar but smaller. With or without AEL, there were moderate to large positive effects associated with reactive CMJ (second jump in a set, compared to the first) on peak and mean eccentric velocity (es = 1.7, 0.8, respectively; both p < 0.01), peak and mean eccentric force (es = 1.3, 1.2, p < 0.01), eccentric loading rate (es = 1.3, p < 0.01) and muscle activity (es = 1.8−1.9, p < 0.01). Concentric variables did not differ. Thus, the flight phase and act of landing during reactive jumps elicited greater increases in eccentric forces, loading rates, and muscle activity than AEL. Nonetheless, kinetic variables were greatest when AEL was combined with reactive jumping. Considering the limitations or complexity associated with most AEL protocols, sets of repetitive (reactive) CMJ may be more pragmatic for augmenting eccentric kinetic variables and neuromuscular stimuli during training.

3.
Sports (Basel) ; 9(9)2021 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-34564328

RESUMO

Velocity-based training (VBT) is a resistance training method by which training variables are manipulated based on kinematic outcomes, e.g., barbell velocity. The better precision for monitoring and manipulating training variables ascribed to VBT assumes that velocity is measured and communicated correctly. This study assessed the validity of several mobile and one stationary VBT device for measuring mean and peak concentric barbell velocity over a range of velocities and exercises, including low- and high-velocity, ballistic and non-ballistic, and plyometric and non-plyometric movements, and to quantify the isolated effect of device attachment point on measurement validity. GymAware (r = 0.90-1, standard error of the estimate, SEE = 0.01-0.08 m/s) and Quantum (r = 0.88-1, SEE = 0.01-0.18 m/s) were most valid for mean and peak velocity, with Vmaxpro (r = 0.92-0.99, SEE = 0.02-0.13 m/s) close behind. Push (r = 0.69-0.96, SEE = 0.03-0.17 m/s) and Flex (r = 0.60-0.94, SEE = 0.02-0.19 m/s) showed poorer validity (especially for higher-velocity exercises), although typical errors for mean velocity in exercises other than hang power snatch were acceptable. Effects of device placement were detectable, yet likely small enough (SEE < 0.1 m/s) to be negligible in training settings.

4.
J Funct Morphol Kinesiol ; 5(2)2020 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33467241

RESUMO

We are glad to introduce the Second Journal Club of Volume Five, Second Issue. This edition is focused on relevant studies published in the last few years in the field of resistance training, chosen by our Editorial Board members and their colleagues. We hope to stimulate your curiosity in this field and to share with you the passion for the sport, seen also from the scientific point of view. The Editorial Board members wish you an inspiring lecture.

5.
J Funct Morphol Kinesiol ; 5(4)2020 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-33467289

RESUMO

We are glad to introduce the Journal Club of Volume Five, fourth Issue. This edition is focused on relevant studies published in the last few years in the field of corrective exercise, chosen by our Editorial Board members and their colleagues. We hope to stimulate your curiosity in this field and to share a passion for sport with you, seen also from the scientific point of view. The Editorial Board members wish you an inspiring lecture.

6.
Bioresour Technol ; 150: 89-97, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24157680

RESUMO

In this work, the conceptual designs of the established Organosolv process and a novel biphasic, so-called Organocat process are developed and analyzed. Solvent recycling and energy integration are emphasized to properly assess economic viability. Both processes show a similar energy consumption (approximately 5 MJ/kg(dry biomass)). However, they still show a lack of economic attractiveness even at larger scale. The Organocat process is more favorable due to more efficient lignin separation. The analysis uncovers the remaining challenges toward an economically viable design. They largely originate from by-products formation, product isolation, and solvent recycling. Necessary improvements in process chemistry, equipment design, energy efficiency and process design are discussed to establish economically attractive Organosolv-like processes of moderate capacity as a building block of a future biorefinery.


Assuntos
Biomassa , Biotecnologia/economia , Biotecnologia/métodos , Compostos Orgânicos/química , Solventes/química , Fracionamento Químico , Custos e Análise de Custo , Termodinâmica
7.
J Pediatr Health Care ; 22(6): 378-82, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18971084

RESUMO

The purpose of this study was to determine if providing a sticker after a finger stick for hemoglobin check reduced pain perception among preschool-aged children. The hypothesis was: Sticker rewards influence the perception of pain as measured by the Oucher scale following a finger stick to check hemoglobin. Preschoolers from Headstart Centers in a southeastern city were recruited for the study. The age range of participants was between 3 and 5 years. The children were assigned randomly into two groups: those receiving stickers (Group I), and those not receiving a sticker (Group II). Subsequently, each participant's pain level was assessed using the Oucher scale within 1 minute of the finger stick. There was no statistically significant difference in pain scale ratings between the two groups when comparing whether or not a cartoon sticker was given t (-.937, df 128, P = .351; 95% confidence interval). This study was clinically significant in that nonpharmacological interventions were utilized in an attempt to reduce pain in young children. Future research should determine whether receiving rewards (such as a cartoon sticker, adhesive bandages, or small toys) alone or in conjunction with distraction measures are efficacious in pain reduction in younger children.


Assuntos
Desenhos Animados como Assunto , Dedos , Hemoglobinas/análise , Dor/psicologia , Pré-Escolar , Humanos , Medição da Dor
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA