The effect of ambient pressure on the heat transfer of a water spray

The present work is aimed at quantifying the effects of ambient pressure in the heat transfer at single injections of a full cone spray over a hot metal surface. The experimental configuration is that of a spray impinging down perpendicularly onto a flat surface located at 55 mm inside an injection chamber. The experiments were conducted for prescribed initial wall temperatures ranging from single phase to local nucleate boiling and transition regimes of heat transfer. Ambient pressures ranged from atmospheric to 30 bar. The analysis is based on spatial resolved measurements of the instantaneous surface temperature during the injection period. The measurements are then processed in order to obtain estimates of the time-averaged values of the local heat flux. The overall cooling rate is also obtained by integrating the local values within the total area of the spray impact Results show that the amount of heat extracted by the impinging spray increases 3.4 times when ambient pressure is increased from atmospheric to 20 bar at the same superheating degree at the wall of 45 degrees C. This corresponds to an increase from 13.3% to 47.7% in the ratio between the actual cooling and the theoretical maximum cooling, defined here as cooling efficiency. This is a result of a better spreading of the liquid film at the wall, covering a larger footprint upon impact. Instantaneous peak heat flux is also increased, as a clear indication of the improved heat transfer between the impinging droplets and the wall.The work presented herein derives from a broader research program devised to develop a system for in cylinder cooling of internal combustion engines using high pressure water sprays produced by gasoline direct injectors.The authors would like to acknowledge LiquidPiston INC. for providing all the laboratorial conditions to perform the experiments, MEtRICs - Mechanical Engineering and Resource Sustainability Centre (UID/EMS/04077/2019), and Diogo Ferreira for aiding in the highspeed visualization setup and experiments. T. Costa is supported by the Portuguese Foundation for Science and Technology (FCT) under the PhD grant PD/BD/105929/2014, MIT Portugal Program, and F.P. Brito is supported by FCT under the Post doctoral grant SFRH/BPD/89553/2012 and J. Martins is supported by the FCT grant SFRH/BSAB/142994/2018, financed by FEDER funds through Programa Operacional Fatores de Competitividade - COMPETE and National funds through PIDDAC and FCT

Diagnóstico Citogenético em Líquidos Amnióticos Realizado entre 2000-2011 no Centro de Genética Médica Jacinto Magalhães, INSA, IP

Introdução: O diagnóstico pré-natal citogenético efetuado em líquido amniótico é um método seguro e fiável para deteção de anomalias cromossómicas fetais, sendo habitualmente realizado a partir das 15 semanas de gestação. Obtêm-se resultados, em média, após 8-10 dias de cultura dos amniócitos. Objectivo: Apresentar a estatística dos resultados obtidos na análise citogenética de líquidos amnióticos realizada na Unidade de Citogenética do Centro de Genética Médica Jacinto Magalhães entre 2000 e 2011, comparando-os com o descrito na literatura. Material e métodos: Entre janeiro de 2000 e dezembro de 2011 foram processados 10149 líquidos amnióticos. Os motivos para a realização da amniocentese foram, nomeadamente, idade materna avançada, anomalias ecográficas, marcadores ecográficos, rastreio bioquímico positivo, familiares com anomalias cromossómicas e risco de doença monogénica. Foram realizadas culturas de amniócitos de acordo com as técnicas convencionais de citogenética e os cromossomas identificados com bandas GTG ou GTL. Sempre que necessário efetuaram-se estudos de citogenética molecular (FISH) com as sondas adequadas ao esclarecimento do caso. Resultados: A análise revelou 342 cariótipos anormais (3,4%) dos quais 234 tinham anomalias numéricas e 108 estruturais. Os Síndromes de Down, de Edwards e de Turner foram as anomalias mais frequentes. Vinte e três culturas não cresceram, representando uma percentagem de 0,2% de insucesso. Conclusões: Os autores correlacionam os resultados obtidos com as indicações clínicas fornecidas e comparam-nas com o descrito na literatura. O presente estudo poderá ser utilizado para o estabelecimento de uma base de dados a nível nacional

Efficiency improvement of vehicles using temperature controlled exhaust thermoelectric generators

One of the main obstacles for the use of thermoelectric generators (TEGs) in vehicles is the highly variable thermal loads typical of driving cycles. Under these conditions it will be virtually impossible for a conventional heat exchanger to avoid both thermal dilution under low thermal loads and TEG overheating under high thermal loads. The authors have been exploring an original heat exchanger concept able to address the aforementioned problems. It uses a variable conductance thermosiphon-based phase-change buffer between the heat source and the TEGs so that a nearly constant, optimized temperature is obtained regardless of operating conditions. To the best of the authors' knowledge, the thermal control feature of the system is unique among existing TEG concepts. The novelty of the present work is the actual computation of operating pressure and temperature and the corresponding vaporization and condensation rates inside the thermosiphon system during driving cycles along with the assessment of the influence of the volumes and pre-charge pressure on electrical output. The global energy and emission savings were also computed for a typical yearly driving profile. It was observed that indeed the concept has unparalleled potential for improving the efficiency of vehicles using TEGs, with around 6% fuel and CO2 emissions savings using the system. This seems a breakthrough for such light duty applications since the efficiency of conventional (passive) systems is strongly deprecated by thermal dilution under low thermal loads and the need to by-pass high thermal load events to avoid overheating. On the contrary, the present concept allows the control of the hot face temperature of the TEGs even under highly variable thermal load (i.e. driving cycle) environments.This work had the support of Fundacao para a Ciencia e Tecnologia, Project Exhaust2Energy (PTDC/EMS-ENE/3009/2014). MEtRICs - Mechanical Engineering and Resource Sustainability Centre (UID/EMS/04077/2019), sabbatical grant (J. Martins) SFRH/BSAB/142994/2018, Post-doctoral grant (F.P. Brito) SFRH/BPD/89553/2012 and M-ERA.NET Project THERMOSS, financed by FEDER funds through P.O. F.C. - COMPETE and National funds through PIDDAC

Energy Resolution studies for NEXT

This work aims to present the current state of simulations of electroluminescence (EL) produced in gas-based detectors with special interest for NEXT --- Neutrino Experiment with a Xenon TPC. NEXT is a neutrinoless double beta decay experiment, thus needs outstanding energy resolution which can be achieved by using electroluminescence. The process of light production is reviewed and properties such as EL yield and associated fluctuations, excitation and electroluminescence efficiencies, and energy resolution, are calculated. An EL production region with a 5 mm width gap between two infinite parallel planes is considered, where a uniform electric field is produced. The pressure and temperature considered are 10 bar and 293 K, respectively. The results show that, even for low values of VUV photon detection efficiency, good energy resolution can be achieved: below 0.4 % (FWHM) at $Q_{\beta\beta}=$2.458 MeV

Performance And Economic Analysis Of Finished Lambs In Feedlot

This study aimed to evaluate animal performance and economic performance of feedlot crossbred lambs (Santa Inês+ - Suffolk) fed different diets based on hay from Cynodon dactylon genotypes, through the use of financial measures considering only the period of feedlot, without relating it to the complete management cycle. A total of 30 intact crossbred Suffolk lambs, identified with earrings, with an average age of 90 days and an average body weight of 21.5 kg were used in this study. Diets were formulated using as treatments a standard concentrate and hay of the Cynodon dactylon genotypes Jiggs, Vaquero, Tifton 68, Coast-Cross, Tifton 85 and Russell in a 60:40 forage-to-concentrate ratio. The treatments were distributed in a randomized complete block design with five replicates. There were significant differences between diets in terms of total expenditure on food, and the highest values were obtained for the Jiggs genotype (BRL 48.96/animal). The animals fed diets based on Tifton 68 hay had a higher rate of return (2.16%) and profitability (34.63%) compared to the other diets. The use of diets based on Tifton 68 hay for feedlot lambs in the finishing phase brings higher economic returns compared to the remaining diets.37129330

Acúmulo de nitrogênio, fósforo, potássio, cálcio, magnésio e enxofre pela videira (Vitis labrusca L. X Vitis vinifera L.) cv. 'Niágara rosada', durante um ciclo vegetativo

Plant material from a well fertilized 7 years-old vineyard var. 'Niagara Rosada' (Vitis labrusca L. X Vitis vinifera L.), situated on an Entisol at country of Jundiai, SP, Brazil, was harvested every fifteen days up to 150 days. The plants were divided into: terminal and basal leaves, terminal and basal shoots, and canes, as well grapes. The plant material was analysed by conventional methods for N, P, K, Ca, Mg, S. The research was conducted in order: a. to obtain information on the accumulation of dry matter, during a period of one year; b. to obtain data on the absorption and distribuition of the nutrients by the grapevine; c. to obtain data on the exportation of nutrients by the shoots and by the grapes. Conclusions : The maximum accumulation of the dry matter took place at the age of 148 days. The leaves present always a higher concentration in nutrients than the other parts of the plant. The leaves, shoots and grapes present different concentration of the nutrients during the year. The maximun absorption by the leaves, shoots and grapes in mg per plant was observed at the following age (days): The grapevine exported by shoots (pruned) and by grapes the following quantities of nutrients in mg per plant: A vineyeard of 5.000 plants per hectare content the following quantities of nutrients: N: 90.85 kg; P:28.40 kg; K: 97.60 kg; Ca: 41.20 kg; Mg: 8.10 kg; S: 9.30 kg.Ensaio foi conduzido com videiras de cultivar 'Niagara Rosada' (Vitis labrusca L. X Vitis vinifeva L.) com 7 anos de idade, no município de Jundiaí, SP (23°12' de latitude sul e 46º33' de longitude oeste e 715 m de altitude), situadas sobre um Regossolo unidade Currupira, com os objetivos de: (1) analisar o crescimento (produção de materia seca); (2) determinar as quantidades de nutrientes absorvidos pela videira nos diferentes estádios de desenvolvimento e (3) avaliar a exportação de nutrientes pela cultura durante o ciclo vegetativo. Após a brotação da videira, foram realizadas 17 coletas quinzenais de material. Foram coletadas e separadas as folhas das partes terminal e basal, sarmentos das partes terminal e basal e cachos. No material coletado foram determinados os teores de N, P, K, Ca, Mg e S. Curvas representativas dos acúmulos de matéria seca e das concentrações dos nutrientes nas partes da planta, em função da idade, foram obtidas a partir dos dados calculados através de equações de regressão. Pelos pontos de máximo estimaram-se a produção maxima de matéria seca e as quantidades de nutrientes extraídos. Conclui-se que: . A produção maxima de materia seca ocorre aos 148 dias. . A concentração dos nutrientes é sempre maior nas folhas do que nos sarmentos e existem diferenças nas concentrações de nutrientes das folhas, sarmentos e cachos, em função da idade. . Os acúmulos máximos de nutrientes nas folhas, sarmentos e cachos ocorrem nas seguintes idades

Different methods of cell quantification can lead to different results : a comparison of digital methods using a pilot study of dendritic cells in HIV-positive patients

Although new digital pathology tools have improved the positive cell quantification, there is a heterogeneity of the quantification methods in the literature. The aim of this study was to evaluate and propose a novel dendritic cells quantification method in squamous cell carcinoma comparing it with a conventional quantification method. Twenty-six squamous cell carcinomas HIV-positive cases affecting the oropharynx, lips and oral cavity were selected. Immunohistochemistry for CD1a, CD83, and CD207 was performed. The immunohistochemical stains were evaluated by automated examination using a positive pixel count algorithm. A conventional quantification method (unspecific area method; UA) and a novel method (specific area method; SA) were performed obtaining the corresponding density of positive dendritic cells for the intratumoral and peritumoral regions. The Mann-Whitney U test was used to verify the influence of the quantification methods on the positive cell counting according to the evaluated regions. Data were subjected to the ANOVA and Student?s t-test to verify the influence of the tumour location, stage, histological grade, and amount of inflammation on the dendritic cells density counting. The cell quantification method affected the dendritic cells counting independently of the evaluated region (P-value <0.05). Significant differences between methods were also observed according to the tumour features evaluations. The positive cell quantification method influences the dendritic cells density results. Unlike the conventional method (UA method), the novel SA method avoids non-target areas included in the hotspots improving the reliability and reproducibility of the density cell quantification