278 research outputs found
A Trnsys Simulation of a Solar-Driven Air Refrigerating System for a Low-Temperature Room of an Agro-Industry site in the Southern part of Italy
Solar cooling technologies are of great interest because the cooling load in buildings is directly correlated to the intensity of solar radiation. In this paper, a feasibility study of a solar cooling system for a cold room in the Southern part of Italy is carried out. This feasibility study can be an example for future achievements in Southern of Italy. The cold room is part of an agro-industrial structure; the set point of temperature is 10°C. The room is 11.0 m long, 9.5 m wide and 3.5 m high. Two sliding doors 3.0 m high are present and strawberries are inside mainly. Thermal loads are evaluated by means of the software TRNSYS 17. Parabolic Though Collectors (PTCs) are employed to capture the solar energy. The solar field extends for 210 m2. Two double-effect chillers (with a total installed power equal to 150 kW) for the collectors are employed. In addition, a conventional heat pump is installed to meet the demand for refrigeration during unfavorable weather conditions or during the maintenance of chillers. There are two different storage tanks: a tank with volume 10 m3 for hot water storage and a tank with volume 40 m3 for cold storage. The terminal part is constituted by dry coolers. Results are given in terms of heat transfer rates and solar fraction. Besides, an economic analysis is carried out to evaluate the payback time
Gains from Variety: Refugee-Host Interactions in Uganda
Refugees are mainly hosted in low-income countries, where they often remain for a long time. Therefore, it is important to assess how they integrate with the local economy and to what extent their presence can contribute to the transition to a more dynamic economic environment. Proximity between refugees and hosts might improve the welfare of both groups by increasing opportunities for
mutually beneficial economic exchanges. In particular, welfare gains might be generated through the
availability of a greater variety of commodities.
In this paper we propose a theoretical model that uses the love for variety to frame the possible benefits arising from the interaction between hosts and refugees facilitated by geographical proximity. We complement the conceptual framework with an empirical analysis that makes use of a
unique dataset covering around 80% of the refugee population living in Ugandan settlements and the adjoining host households. The empirical results show that proximity between groups increases the food expenditure and the
variety of food consumption of both groups. We also found that exposition to inter-group interactions rises the non-food expenditure, and the probability to run a farm and a non-farm enterprise by refugee households, while hosts are not crowding out from production
Demographics of the M-star Multiple Population in the Orion Nebula Cluster
We present updated results constraining multiplicity demographics for the
stellar population of the Orion Nebula Cluster (ONC, a high-mass, high-density
star-forming region), across primary masses 0.08-0.7M. Our study
utilizes archival Hubble Space Telescope data obtained with the Advanced Camera
for Surveys using multiple filters (GO-10246). Previous multiplicity surveys in
low-mass, low-density associations like Taurus identify an excess of companions
to low-mass stars roughly twice that of the Galactic field and find the mass
ratio distribution consistent with the field. Previously, we found the
companion frequency to low-mass stars in the ONC is consistent with the
Galactic field over mass ratios=0.6-1.0 and projected separations=30-160au,
without placing constraints on the mass ratio distribution. In this study, we
investigate the companion population of the ONC with a double point-spread
function (PSF) fitting algorithm sensitive to separations larger than 10au
(0.025") using empirical PSF models. We identified 44 companions (14 new), and
with a Bayesian analysis, estimate the companion frequency to low-mass stars in
the ONC =0.13 and the power law fit index to the mass ratio
distribution =2.08 over all mass ratios and projected
separations of 10-200au. We find the companion frequency in the ONC is
consistent with the Galactic field population, likely from high transient
stellar density states, and a probability of 0.002 that it is consistent with
that of Taurus. We also find the ONC mass ratio distribution is consistent with
the field and Taurus, potentially indicative of its primordial nature, a direct
outcome of the star formation process.Comment: 23 pages, 11 figures, Accepted to ApJ Nov. 3, 202
Papillary thyroid microcarcinoma: time to shift from surgery to active surveillance?
The incidence of differentiated thyroid cancer is increasing greatly in high-income countries. Roughly 50% of this increase is attributable to the identification of intrathyroidal papillary thyroid microcarcinomas. Since mortality associated with these tumours remains low and stable, the increasing diagnosis has led to concerns about overdiagnosis and overtreatment. Management of papillary thyroid microcarcinomas should take into account the reported absence of mortality when diagnosed in the absence of lymph node metastases and distant metastases, as shown even in recent studies promoting active surveillance; a low recurrence rate of 1-5%; and the risk of permanent complications from surgery that cannot be decreased to less than 1-3%, even in high-volume tertiary care centres with experienced surgeons. On the basis of these data, active surveillance with curative intent, in which active treatment is delayed until the cancer shows signs of significant progression to avoid side-effects of treatment, should be considered in properly selected patients
Abundance and distribution of zooplankton in the South China Sea, Area III: Western Philippines
A survey on the zooplankton in the waters of western Philippines was carried out from April 18 to May 9, 1998. The estimate of zooplankton biomass ranged from 0.92 mg/m3 to 20.85 mg/m3 with a mean of 5.70 mg/m3. Maximum and minimum densities of zooplankton recorded were 4683/m3 in station 16 and 446/m3 in station 5, respectively. The zooplankton communities were comprised of 37 different categories of animal groups. Copepods were the most dominant group in zooplankton communities at all stations but their abundance varied from 5% to 43% of the total zooplankton
The Category of Node-and-Choice Forms, with Subcategories for Choice-Sequence Forms and Choice-Set Forms
The literature specifies extensive-form games in many styles, and eventually
I hope to formally translate games across those styles. Toward that end, this
paper defines , the category of node-and-choice forms. The
category's objects are extensive forms in essentially any style, and the
category's isomorphisms are made to accord with the literature's small handful
of ad hoc style equivalences.
Further, this paper develops two full subcategories: for
forms whose nodes are choice-sequences, and for forms whose
nodes are choice-sets. I show that is "isomorphically enclosed"
in in the sense that each form is isomorphic to
a form. Similarly, I show that is
isomorphically enclosed in in the sense that each
form with no-absentmindedness is isomorphic to a
form. The converses are found to be almost immediate, and the
resulting equivalences unify and simplify two ad hoc style equivalences in
Kline and Luckraz 2016 and Streufert 2019.
Aside from the larger agenda, this paper already makes three practical
contributions. Style equivalences are made easier to derive by [1] a natural
concept of isomorphic invariance and [2] the composability of isomorphic
enclosures. In addition, [3] some new consequences of equivalence are
systematically deduced.Comment: 43 pages, 9 figure
Thermal and optical characterization of tetrathylene glycol -based solar nanofluid at high temperature conditions
Nanofluids are defined as dilute suspensions with solid particles smaller than 100 nm. Nanofluids present some important advantages over the conventional colloidal suspensions such as high stability, reduced particle clogging and high heat transfer capabilities. Most of published works have been focused on the increment of thermal conductivity in water-based nanofluids with high nanoparticle loads.
Solar nanofluids are a type of nanofluids with low nanoparticle loads and suitable for direct solar radiation harvesting. In this case, nanoparticles in the heat transfer fluid directly absorbs the solar radiation, transferring the heat to the heat transfer fluid. In this way, high efficiency from solar radiation to thermal energy can be obtained since the heat exchange area (nanoparticle surface area) is extremely high and the peak temperature is inside the heat transfer fluid. In most published works, thermal and optical characterizations of solar nanofluids are performed at room temperature conditions, far away from experimental conditions found in real applications.
In this work, a complete thermal and optical characterization of a tetraethylene glycol – based nanofluid using tin nanoparticles have been performed. Nanoparticle morphology and nanoparticle cluster size have been characterized at room conditions and thermal conductivity, specific heat capacity and transmission spectrum have been measured at different temperatures between 50ºC and 150ºC. Nanoparticle morphology has been characterized by Transmission Electron Microscope and cluster size by Dynamic Light Scattering technique, thermal conductivity have been measured by the hot wire technique, the specific heat capacity by a Differential Scanning Calorimeter and the transmission spectrum by a fiber optic based spectrometer and a special designed nanofluid cuvette with controlled temperature conditions.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016
Accelerated partial breast irradiation using 3D conformal radiotherapy: Toxicity and cosmetic outcome
Purpose: The aim of this paper is to analyze the incidence of acute and late toxicity and cosmetic outcome in breast cancer patients submitted to breast conserving surgery and three-dimensional conformal radiotherapy (3D-CRT) to deliver accelerated partial breast irradiation (APBI). Methods and materials: 84 patients were treated with 3D-CRT for APBI. This technique was assessed in patients with low risk stage I breast cancer enrolled from September 2005 to July 2011. The prescribed dose was 34/38.5 Gy delivered in 10 fractions twice daily over 5 consecutive days. Four to five nocoplanar 6 MV beams were used. In all CT scans Gross Tumor Volume (GTV) was defined around the surgical clips. A 1.5 cm margin was added by defining a Clinical Target Volume (CTV). A margin of 1 cm was added to CTV to define the planning target volume (PTV). The doseevolume constraints were followed in accordance with the NSABP/RTOG protocol. Late toxicity was evaluated according to the RTOG grading schema. The cosmetic assessment was performed using the Harvard scale. Results: Median patient age was 66 years (range 51e87). Median follow-up was 36.5 months (range 13 e83). The overall incidence of acute skin toxicities was 46.4% for grade 1 and 1% for grade 2. The incidence of late toxicity was 16.7% for grade 1, 2.4% for grade 2 and 3.6% for grade 3. No grade 4 toxicity was observed. The most pronounced grade 2 late toxicity was telangiectasia, developed in three patients. Cosmetics results were excellent for 52%, good for 42%, fair for 5% and poor for 1% of the patients. There was no statistical correlation between toxicity rates and prescribed doses (p ¼ 0.33) or irradiated volume (p ¼ 0.45). Conclusions: APBI using 3D-CRT is technically feasible with very low acute and late toxicity. Long-term results are needed to assess its efficacy in reducing the incidence of breast relapse
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