132 research outputs found
Thermal comfort for pregnant sows housed in individual and group stalls
Este experimento foi realizado no período compreendido entre 04/01 e 11/03/2005, em uma propriedade de produção industrial de suínos, localizada no município de Elias Fausto, estado de São Paulo. O objetivo da pesquisa consistiu na avaliação de diferentes sistemas de alojamento para matrizes gestantes, verificando-se as influências dos elementos meteorológicos e os aspectos relacionados à qualidade química do ar e seus reflexos no conforto animal na fase de gestação, determinando-se as condições favoráveis ao melhor desempenho animal, com base nas respostas ao ambiente de criação. O estudo foi desenvolvido no setor de gestação, com 24 matrizes primíparas, 12 fêmeas alojadas em baias individuais (T1) e 12 animais em baias coletivas (T2). O trabalho foi dividido em duas etapas: análise bioclimática e análise da qualidade química do ar. O delineamento experimental foi em blocos casualizados, com dois tratamentos e 67 blocos, e as médias comparadas pelo teste de Tukey. As variáveis meteorológicas (T, °C e h, kJ kg-1) apontam o sistema de alojamento em baias coletivas como aquele que permitiu melhor condicionamento térmico natural às matrizes em gestação apresentando valores da ordem de 25,03 °C e 62,02 kJ kg-1. As concentrações dos teores de gases não superaram as concentrações consideradas críticas para as matrizes.The experiment was carried out from January 4 to March 11, 2005 in a farm specialized in industrial production of pork, located in Elias Fausto, São Paulo State. This study evaluated different housing systems for pregnant sows looking at meteorological element influences and aspects of air chemical quality on the animal thermal comfort. The optimal conditions for animal performance improvement were determined by analyzing behavioral data taken in the breeding environment. In the gestation facility 24 gilts were allocated: 12 in individual stalls (T1) and 12 in group housings (T2). This study was divided into two steps: bioclimatic analysis and analysis of the chemical quality of air. An experimental design using randomized blocks with two treatments and 67 blocks was used. Means were compared by the Tukey test. The variables (T, °C e h, kJ kg-1) indicated which confinement system in group-houses was the one that permitted the better natural thermal environment for pregnant gilts with values of 25.03 °C and 62.02 kJ kg-1. In relation to concentration of gases, mean levels did not exceed the concentrations considered limiting for sows
Surface rehabilitation of Portland cement concrete (PCC) pavements using single or double surface dressings with soft bitumen, conventional or modified emulsions
Surface dressings are a sustainable maintenance alternative for pavements with surface distresses, due to
the low amount of resources involved. This paper aims to analyze the viability of using twelve different
surface dressing solutions, including three binders (conventional and modified emulsions, and a soft
160/220 bitumen) and a covering with diluted emulsion, for surface treatment of Portland cement concrete
(PCC) pavements. Several test methods were used to evaluate the macrotexture, skid resistance,
adhesion, and resistance to wearing on a large scale prototype. In general, single surface dressings
increased further the macrotexture of the concrete pavement surface. The skid resistance of single and
double surface dressings was similar. The best surface dressing in the pull-off test was that with the
160/220 bitumen. The conventional and modified emulsions presented similar mechanical adhesion in
the Vialit plate test. Concerning the prototype wearing test, the best result was obtained for the double
surface dressing with bitumen covered with diluted emulsion. Based on this work’s results, the surface
dressings are a potential surface rehabilitation alternative for concrete pavements.This work was partially financed by FCT / MCTES through
national funds (PIDDAC) under the R&D Unit Institute for Sustainability and Innovation in Structural Engineering (ISISE), under reference UIDB/04029/2020. This work is financed by national funds
through FCT - Foundation for Science and Technology, under grant
agreement SFRH/BD/137421/2018 attributed to the 1st author
Efficient Battery Usage in Wireless-Powered Cell-Free Systems with Self-Energy Recycling
This paper investigates wireless-powered cell-free systems, in which the
users send their uplink data signal while simultaneously harvesting energy from
network nodes and user terminals - including the transmitting user terminal
itself - by performing self-energy recycling. In this rather general setting, a
closed-form lower bound of the amount of harvested energy and the achieved
signal-to-interference-plus-noise ratio expressions are derived. Then, to
improve the energy efficiency, we formulate the problem of minimizing the
users' battery energy usage while satisfying minimum data rate requirements.
Due to the non-convexity of the problem, a novel alternating optimization
algorithm is proposed, and its proof of convergence is provided. Finally,
numerical results show that the proposed method is more efficient than a
state-of-art algorithm in terms of battery energy usage and outage rate.Comment: Accepted as a correspondance at IEEE TV
Mixed Coherent and Non-Coherent Transmission for Multi-CPU Cell-Free Systems
Existing works on cell-free systems consider either coherent or non-coherent
downlink data transmission and a network deployment with a single central
processing unit (CPU). While it is known that coherent transmission outperforms
noncoherent transmission when assuming unlimited fronthaul links, the former
requires a perfect timing synchronization, which is practically not viable over
a large network. Furthermore, relying on a single CPU for geographically large
cell-free networks is not scalable. Thus, to realize the expected gains of
cellfree systems in practice, alternative transmission strategies for realistic
multi-CPU cell-free systems are required. Therefore, this paper proposes a
novel downlink data transmission scheme that combines and generalizes the
existing coherent and non-coherent transmissions. The proposed transmission
scheme, named mixed transmission, works based on the realistic assumption that
only the access points (APs) controlled by a same CPU are synchronized, and
thus transmit in a coherent fashion, while APs from different CPUs require no
synchronism and transmit in a non-coherent manner. We also propose extensions
of existing clustering algorithms for multi-CPU cell-free systems with mixed
transmission. Simulation results show that the combination of the proposed
clustering algorithms with mixed transmission have the potential to perform
close to the ideal coherent transmission.Comment: Submitted for possible publication in IEEE conferenc
Performance of tiles composed of blast furnace slag and vegetable fiber in prototype barns
Busca-se, em todo o mundo, a substituição do cimento amianto por alternativas seguras para o ambiente e para a saúde do trabalhador, além de econômicas, razão por que o uso de fibras vegetais como aglomerado em países tropicais onde estes resíduos são abundantes, tem-se mostrado bastante viável. No presente experimento foram comparadas telhas de cimento amianto pintadas com tinta reflexiva, telhas cerâmicas e telhas compostas de uma matriz à base de cimento Portland CPII 32Z (ABNT NBR-5735), escória de alto-forno (EAF) e sílica ativa, reforçadas com fibras de polpa celulósica de sisal (Agave sisalana). Utilizaram-se protótipos de galpões avícolas nos quais o calor produzido pelas aves foi simulado por lâmpadas incandescentes. Para caracterização do ambiente térmico lançou-se mão dos índices de conforto: ITU (índice de temperatura e umidade), ITGU (índice de temperatura de globo e umidade), CTR (carga térmica radiante) e entalpia (H) em que os resultados demonstraram que as telhas compostas apresentaram comportamento térmico semelhante ao das telhas cerâmicas, podendo ser utilizadas em substituição às telhas de cimento amianto.The substitution of cement asbestos by safer and equally economical alternatives has being searched for throughout the world. The usage of vegetal staple fiber as agglomerate in tropical countries where these residues are abundant has shown it self to be viable. In this study, roofing tiles fabricated with cement base Portland CPII 32Z (ABNT NBR-5735), blast furnace slag (EAF), active silica reinforced with cellulose pulp staple fibers of sisal (Agave sisalana) were compared with cement asbestos roofing tiles with white paint and ceramic roofing tiles. Prototypes of poultry facilities were used and lamps simulated the heat produced by the birds. Indices ITU, ITGU, CTR and entalpy (H) were employed for the characterization of the thermal atmospheric comfort and the results showed that the alternative roofing tiles were similar to the ceramic tiles and could be used as a substitute for asbestos roofing tiles
Development of core-sheath phase change fibres incorporated with PEG2000 for thermoregulation applications
The resilience of urban infrastructures in the face of climate challenges has become a public concern, with direct impacts on the well-being of citizens due to frequent environmental, economic and social influences. Asphalt pavements, widely present in urban centres, contribute negatively to the Urban Heat Islands (UHI) effect, which is responsible for slowly absorbing and releasing heat due to their dark surfaces.
The incorporation of phase change materials (PCM) into these asphalt mixtures, as highlighted in the literature, has emerged as an effective solution to improve thermoregulation with the aim of mitigating problems associated with UHI. This topic is directly related to the objectives SDG9, SDG11, and SDG12 of the United Nations (UN), associated with resilient and sustainable cities, and represents a considerable challenge that must be addressed.
Therefore, this research aims to evaluate the ideal composition of PCFs comprising a cellulose acetate sheath (CA, Mn 30,000 and 50,000) and a polyethene glycol (PEG) 2000 core as PCM, produced by the wet spinning method. The presence and influence of PEG 2000 inside PCFs were investigated morphologically, chemically and thermally using bright-field microscopy, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), respectively.
Using a bright-field microscope, it was possible to observe the difference between the sheath and the core of the PCFs and revealed that the morphologies of the PCFs depend on the ejection speed of PEG 2000. TGA confirmed the capability of PCFs to resist high temperatures. DSC confirmed the phase change of PEG 2000, as its peaks with melting points were close to those of virgin PEG 2000, with a slight change caused by the protective CA sheath. Therefore, the results revealed a successful Production of PCFs through wet spinning confirming the compatibility of the phase change temperature of PEG 2000 with the application to infrastructures subjected to moderate temperature between 50-60 °C.This research was partially funded by the Foundation for Science and Technology (FCT) under the projects MicroCoolPav EXPL/EQU EQU/1110/2021, NanoAir PTDC/FISMAC/6606/2020 (DOI: 10.54499/PTDC/FIS-MAC/6606/2020) and within the framework of Strategic Funding UIDB/04650/2020, UIDB/04029/2020 (DOI: 10.54499/UIDB/04029/2020) and UID/QUI/0686/2020. Iran Rocha Segundo and Helena Prado Felgueiras thank FCT for funding 2022.00763.CEECIND (DOI: 10.54499/2022.00763.CEECIND/CP1718/CT0006) and 2021.02720.CEECIND (DOI: 10.54499/DL57/2016/CP1377/CT0098)
Coaxial fibres incorporated with phase change materials for thermoregulation applications
Nowadays, the growing concern about improving thermal comfort in different structures (textiles, buildings, and pavements, among others) has stimulated research into phase change materials (PCMs). The direct incorporation of PCMs into composite materials can cause mechanical impacts. Therefore, this study focuses on the design of phase change coaxial fibres (PCFs), using commercial cellulose acetate (CA) or recycled CA obtained from cotton fabrics (CAt) as the sheath and polyethylene glycol (PEG) 2000 as the core, via the wet spinning method; the fibres vary in molecular weight, concentration and ejection velocity. The fibres were assessed for their optical, chemical, thermal, and mechanical properties. The presence of PEG2000 is confirmed in the core of the fibres. Thermal analyses revealed a mass loss at high temperatures, attributable to the presence of PEG2000. Notably, the fibres with CA (Mn 30,000) showed superior thermal and mechanical performance. The melting point of PEG2000 incorporated into these PCFs coincided with the melting point of pure PEG2000 (about 55 °C), with a slight deviation, indicating that PCFs were obtained. Finally, the results point to the application of the fibres in civil engineering materials requiring a phase change between 50 and 60 °C, providing promising prospects for their use in applications requiring thermoregulatory properties.This research was funded by the Portuguese Foundation for Science and Technology (FCT) under the projects MicroCoolPav EXPL/EQUEQU/1110/2021 and NanoAir PTDC/FISMAC/6606/2020 (https://doi.org/10.54499/PTDC/FIS-MAC/6606/2020) and within the framework of Strategic Funding UIDB/04650/2020, UIDB/04029/2020 (https://doi.org/10.54499/UIDB/04029/2020) and UID/QUI/0686/2020. I.R.S. and H.P.F. would like to thank FCT for their funding contracts 2022.00763.CEECIND (https://doi.org/10.54499/2022.00763.CEECIND/CP1718/CT0006) and 2021.02720.CEECIND (https://doi.org/10.54499/DL57/2016/CP1377/CT0098)
Photocatalytic performance of textiles coated with TiO2-RGO system for degradation of crude petroleum under similar solar irradiation
The pollution caused by oil and its toxic derivatives presents a considerable risk to the
public health and the environment. Here, we studied the influence of TiO2 nanoparticles
immobilized on three types of textiles materials (Cotton, Entretela and PLA) coated with
reduced graphene oxide (RGO) to be used for degradation of crude petroleum under
simulated solar irradiation. The morphological studies of the functionalized textiles
substrates were performed by using Scanning Electron Microscopy and Energy
Dispersive X-ray Spectroscopy, which indicated an excellent dispersion and adhesion of
nanoparticles on the textile fibres covered with RGO. Ultraviolet–visible Diffuse
Reflectance spectra suggests a reduction in the band gap energy of TiO2 due to the
presence of RGO. The excitation/emission Synchronized Fluorescence and Fourier transform Infrared spectroscopies demonstrated that the functionalized textiles substrates
exhibit a great potential for photocatalytic degradation of organic compounds with high
prospects in petroleum and wastewater treatment areas
Evaluation of Ar, Ar-v7, and P160 Family as Biomarkers for Prostate Cancer: Insights Into the Clinical Significance and Disease Progression
PURPOSE: To assess the role of the p160 family, AR, and AR-V7 in different initial presentations of prostate cancer and their association with clinical endpoints related to tumor progression.
METHODS: The study sample comprises 155 patients who underwent radical prostatectomy and 11 healthy peripheral zone biopsies as the control group. Gene expression was quantified by qPCR from the tissue specimens. The statistical analysis investigated correlations between gene expression levels, associations with disease presence, and clinicopathological features. Additionally, ROC curves were applied for distinct PCa presentations, and time-to-event analysis was used for clinical endpoints.
RESULTS: The AR-V7 diagnostic performance for any PCa yielded an AUC of 0.77 (p \u3c 0.05). For locally advanced PCa, the AR-V7 AUC was 0.65 (p \u3c 0.05). Moreover, the metastasis group had a higher expression of SRC-1 than the non-metastatic group (p \u3c 0.05), showing a shorter time to metastasis in the over-expressed group (p = 0.005). Patients with disease recurrence had super-expression of AR levels (p \u3c 0.0005), with a shorter time-to-recurrence in the super-expression group (p \u3c 0.0001).
CONCLUSION: Upregulation of SRC-1 indicates a higher risk of progression to metastatic disease in a shorter period, which warrants further research to be applied as a clinical tool. Additionally, AR may be used as a predictor for PCa recurrence. Furthermore, AR-V7 may be helpful as a diagnostic tool for PCa and locally advanced cancer, comparable with other investigated tools
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