418 research outputs found

    Mass and heat integration in ethanol production mills for enhanced process efficiency and exergy-based renewability performance

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    This paper presents the process design and assessment of a sugarcane-based ethanol production system that combines the usage of both mass and heat integration (pinch analysis) strategies to enhance the process efficiency and renewability performance. Three configurations were analyzed: (i) Base case: traditional ethanol production (1G); (ii) mass-integrated (1G2G); and (iii) mass and heat-integrated system (1G2G-HI). The overall assessment of these systems was based on complementary approaches such as mass and mass-heat integration, energy and exergy analysis, exergy-based greenhouse gas (GHG) emissions, and renewability exergy criteria. The performances of the three cases were assessed through five key performance indicators (KIPs) divided into two groups: one is related to process performance, namely, energy efficiency, exergy efficiency, and average unitary exergy cost (AUEC), and the other one is associated to environmental performance i.e., exergy-based CO2-equation emissions and renewability exergy index. Results showed a higher exergy efficiency of 50% and the lowest AUEC of all the systems (1.61 kJ/kJ) for 1G2G-HI. Furthermore, the destroyed exergy in 1G2G-HI was lower by 7% and 9% in comparison to the 1G and 1G2G cases, respectively. Regarding the exergy-based GHG emissions and renewability performance (lambda(index)), the 1G2G-HI case presented the lowest impacts in terms of the CO2-equivalent emissions (94.10 gCO(2)-eq/MJ products), while lambda(index) was found to be environmentally unfavorable (lambda = 0.77). However, lambda(index) became favorable (lambda > 1) when the useful exergy of the byproducts was considered710sem informaçãosem informaçã

    Vibration-induced postural reactions: a scoping review on parameters and populations studied

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    ObjectiveMechanical vibration is an effective way for externally activating Ia primary endings of the muscle spindles and skin mechanoreceptors. Despite its popularity in proprioception and postural control studies, there is still no review covering the wide variety of vibration parameters or locations used in studies. The main purpose of this scoping review was thus to give an overview of general vibration parameters and to identify, if available, the rationale for justifying methodological choices concerning vibration parameters.MethodsThree databases (Pubmed, CINHAL, and SPORTDiscus) were searched from inception to July 2022. Included articles were to focus on the study of muscle spindles and skin mechanoreceptors vibration in humans and assess postural control. Following inclusion, data regarding demographic information, populations, vibration parameters and rationale were extracted and summarized.ResultsOne hundred forty-seven articles were included, mostly targeting lower extremities (n = 137) and adults (n = 126). The parameters used varied widely but were most often around 80 Hz, at an amplitude of 1 mm for 10–20 s. Regarding rationales, nearly 50% of the studies did not include any, whereas those including one mainly cited the same two studies, without elaborating specifically on the parameter's choice.ConclusionThis scoping review provided a comprehensive description of the population recruited and parameters used for vibration protocols in current studies with humans. Despite many studies, there remain important gaps of knowledge that needs to be filled, especially for vibration amplitude and duration parameters in various populations

    Evaluation of Water Quality for Water Bathing Conditions on Querer Beach in the Municipality of Santa Rosa, Tocantins

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    The water is an indispensable natural resource for life, economic development, and the conservation and maintenance of ecosystem services. It is known that the quantity and quality of water available for consumption is decreasing considerably and the increasing scarcity of this resource may be associated with factors such as the irregular distribution of water, waste and irrational use of it, socioeconomic and environmental problems, pollution of resources inadequate disposal of sewage, lack of basic sanitation and treatment of sewage, among others. In this way, the environmental problems have gained relevant space in the current discussions due to their importance, making the debates of these questions in the society necessary. Because of the anthropic activities that have been developed in a disorderly way and without planning, it reflects drastically in the environmental degradation, especially in this case, in the quality of the waters, which compromises this natural resource, whatever the purpose of its use. Thus, the objective of this work is to evaluate the water quality of Querer Beach in Santa Rosa-TO, promoting a water bathing condition study. Therefore, to investigate the effects of anthropogenic interferences on water quality, the water quality was evaluated by means of monitoring. The analyzes of the bathing conditions, show the percentages obtained for the situations in which the beach is classified as suitable for bathing, the investigations followed the criteria established by the CONAMA resolution nº 274/00. The water quality at a specific point of the beach was evaluated and monitored for a determined period of six weeks, and the microbiological indicator of water quality according to the Collilert technique according to the methodology described by Standard Methods was used as a parameter. In this way, it was possible to verify the tolerances of the Brazilian parameters for the water bathing conditions indicators of Querer Beach

    The Impact of Pain on Functionality, Postural Control and Fall Risk in Woman Aged 45 to 64 Years Old

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    Background: Ageing in women is associated with chronic degenerative pain leading to a functional decrease and therefore increase fall risk. It is therefore essential to detect early functional decreases in the presence of pain related to osteoarthritis. Objective: This cross-sectional study aimed to assess the impact of pain on functionality, postural control and fall risk in women aged between 45 to 64 years old. Methods: Twenty-one (21) women aged 45 to 64 were evaluated by clinical and functional measures such as a pain questionnaire (Lequesne Index), functional tests (Stair Step Test, 5 times sit-to-stand, 6MWD, Timed-up and Go) and postural performance (under force platform). Women were classified into 2 groups from the Lequesne Pain Index (PI): low pain (score ≤ 9) and strong pain (score ≥ 10) for subsequent comparisons on functionality (physical and postural control performance). Results: A significant impact was observed between the pain index (strong PI) and 3 of the 4 functional tests carried out including Stair Step Test (p = 0.001; g = 1.44), walking distance (p = 0.003; g = 1.31) and Timed-up and Go (p = 0.04; g = −0.93). The group with a strong PI score reported further poor postural control under force platform compared to the weak pain group. Conclusion: Pain and severity based on the PI index negatively modulate physical and postural control performance in women aged 45 to 64 years old

    Immediate effect of bilateral talocrural joint manipulation on postural balance in healthy subjects

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    The aim of this study was to assess the immediate effect of bilateral talocrural joint manipulation on the postural balance of healthy subjects. Ninety healthy subjects (21 males and 69 females) were included in this study. The mean age, height and body weight of the subjects were 22.21 years, 165.1 cm and 62.58 Kg, respectively. Following collection of anthropometric data, the subjects were allocated randomly into an experimental group (receiving real talocrural joint manipulation), a placebo group and a control group. Before and after manipulation, the subjects performed two postural balance tasks, inquiet standing position (eyes open and eyes closed) on a force platform. The stabilometric data were recorded for 60 seconds in each condition. Sway area, medio-lateral (ML) and anteroposterior (AP) velocities and median frequency were calculated from the center of pressure (COP) displacements. The results showed that in the experimental group the COP sway velocity decreased in both directions of movement (AP and ML) and in both visual tasks (eyes open and eyes closed). In general, the placebo and control groups had similar postural balance across balance parameterss. Significant effect of the bilateral talocrural joint manipulation was found on main balance parameter like COP velocity in the anteroposterior and mediolateral directions. These results have some much implications for manual therapy rehabilitation of individuals with ankle instability

    A rational experimental approach to identify correctly the working voltage window of aqueous-based supercapacitors

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    It is common to find in the literature different values for the working voltage window (WVW) range for aqueous-based supercapacitors. In many cases, even with the best intentions of the widening the operating voltage window, the measured current using the cyclic voltammetry (CV) technique includes a significant contribution from the irreversible Faradaic reactions involved in the water-splitting process, masked by fast scan rates. Sometimes even using low scan rates is hard to determine precisely the correct WVW of the aqueous-based electrochemical capacitor. In this sense, we discuss here the best practices to determine the WVW for capacitive current in an absence of water splitting using complementary techniques such as CV, chronoamperometry (CA), and the electrochemical impedance spectroscopy (EIS). To accomplish this end, we prepare and present a model system composed of multiwalled carbon nanotubes buckypaper electrodes housed in the symmetric coin cell and soaked with an aqueous-based electrolyte. The system electrochemical characteristics are carefully evaluated during the progressive enlargement of the cell voltage window. The presence of residual Faradaic current is verified in the transients from the CA study, as well as the impedance changes revealed by EIS as a function of the applied voltage, is discussed. We verify that an apparent voltage window of 2.0 V determined using the CV technique is drastically decreased to 1.2 V after a close inspection of the CA findings used to discriminate the presence of a parasitic Faradaic process. Some orientations are presented to instigate the establishment in the literature of some good scientific practices concerned with the reliable characterization of supercapacitors10CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP310544/2019-0; 301095/2018-32014/02163-7; 2017/11958-1; 2018/20756-

    Battery-like behavior of Ni-ceria based systems: synthesis, surface defects and electrochemical assessment

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    NiO, CeO2 and respective composites are extensively used in energy storage devices due to mostly their high electrochemical activity. However, the assessment of battery-like behavior of Ni-ceria based systems comprising (Ni or Gd)-doped ceria combined with NiO seems to be neglected in the literature. In this work, NiO and ceria-based solid solutions composite powders were obtained by a co-precipitation synthesis method. The structure and particle size of the calcined powders were investigated by X-ray diffractometry (XRD) and field emission scanning electron microscopy (FESEM), respectively. Oxidative states of composites were inspected by X-ray photoelectron spectroscopy (XPS). The electrochemical performance of powders was evaluated by cyclic voltammetry, galvanostatic charge-discharge and impedance spectroscopy. Refinement of the XRD patterns showed that powders have nanosized crystallites and mean size of particles within 20 – 70 nm were revealed by FESEM. The improved specific capacity of the NiO-CeO2 electrode material (about 2.5 times higher than that of NiO-CGO at 5 mV s−1) is due to an increase in Faradic reactions taken place on its surface with a higher fraction of defects (namely Ni3+, Ce3+ and oxygen vacancies), as determined by XPS. The superior electrochemical performance of the NiO-CeO2 electrode is also confirmed by electrochemical impedance spectroscopy.publishe
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