scholarly journals Deshidratador solar híbrido para el secado de plátano

2019 ◽  
pp. 26-33
Author(s):  
Humberto Armando Camacho-Martinez ◽  
Diana Montserrat Antonio-Gordillo ◽  
José Billerman Robles-Ocampo ◽  
Perla Jazmín Sevilla-Camacho
Keyword(s):  
Thermal Conductivity ◽  
Storage System ◽  
Weather Conditions ◽  
The Other ◽  
Raw Material ◽  
Analysis And Evaluation ◽  
Air Convection ◽  
Solar Dryer ◽  
Forced Air ◽  
Control And Measurement System

In this work the design of a solar dryer for the dehydration of fruits is presented. Banana is used as raw material for analysis and evaluation purposes. The system is supplied with solar energy in the form of (photovoltaic) PV and (photothermic) PT. The PV part of the dehydrator consists of a solar panel, whose energy supplies electrical resistances to increase the temperature, also feeding a forced air convection system which is carried out with a pair of fans that are at the entrance and exit of the dehydrator, also a control and measurement system. In the other side the PT part consist in a passive storage system of heat direct and indirect catchment of radiation. For the development of the solar dryer it is necessary to take into account certain parameters such as: weather conditions (solar radiation, ambient temperature and wind speed), thermal conductivity, temperature and properties of the components.

Natural and forced air convection operation in a direct solar dryer assisted by photovoltaic module for drying of green onion

Solar Energy ◽  
2021 ◽  
Vol 220 ◽  
pp. 24-34
Author(s):  
Letícia Ferraresi Hidalgo ◽  
Mariana Nascimento Candido ◽  
Karina Nishioka ◽  
José Teixeira Freire ◽  
Gustavo Nakamura Alves Vieira
Keyword(s):  
Photovoltaic Module ◽  
Air Convection ◽  
Solar Dryer ◽  
Forced Air

Praktiken und Praxis

2017 ◽  
Vol 2017 (2) ◽  
pp. 41-56
Author(s):  
Thomas Alkemeyer
Keyword(s):  
The Self ◽  
The Other ◽  
Raw Material ◽  
Political Agency ◽  
Lived Body ◽  
Sociological Analysis ◽  
Discipline Formation ◽  
Material Basis ◽  
Embodied Self ◽  
Self Formation

Two forms or rather perspectives of observations appear alongside practice theories: The first perspective can be called the „theatre perspective“: practice here is observed as a regular, spatiotemporally ordered, socially structured, and therefore recognizable historical form of „practical doings and sayings“, in which participants are understood as mere carriers of practices and their bodies as the raw material for processes of formation. In the other perspective, understood as the perspective of the participants themselves, practices come into view as ongoing, conflictual, and contingent accomplishments, in which participants occur as intelligently collaborating contributors with so called „lived bodies“. These bodies are affectable, sites of experience, and media of a sensitivity that allow an embodied self to orientate itself (with)in a practice. This paper proposes a methodological mediation of both perspectives by taking into account both a sociological analysis of discipline, formation, or adjustment, and the reflexive sensing in action, which can be modeled phenomenologically. Thus, a „lived-body-in-accomplishment“ comes into view that serves the material basis of subjectivation procceses, i. e. the (self-)formation of a constitutionally conditioned (political) agency.

Maximizing Heat Transfer Through Joint Fin Systems

2005 ◽  
Vol 128 (2) ◽  
pp. 203-206 ◽  
Author(s):  
A.-R. A. Khaled
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Performance ◽  
Critical Length ◽  
The Other ◽  
Rigid Fixation ◽  
Convection Coefficient ◽  
Heat Transfer Characteristics ◽  
Cold Side ◽  
Transfer Characteristics

Heat transfer through joint fins is modeled and analyzed analytically in this work. The terminology “joint fin systems” is used to refer to extending surfaces that are exposed to two different convective media from its both ends. It is found that heat transfer through joint fins is maximized at certain critical lengths of each portion (the receiver fin portion which faces the hot side and the sender fin portion that faces the cold side of the convective media). The critical length of each portion of joint fins is increased as the convection coefficient of the other fin portion increases. At a certain value of the thermal conductivity of the sender fin portion, the critical length for the receiver fin portion may be reduced while heat transfer is maximized. This value depends on the convection coefficient for both fin portions. Thermal performance of joint fins is increased as both thermal conductivity of the sender fin portion or its convection coefficient increases. This work shows that the design of machine components such as bolts, screws, and others can be improved to achieve favorable heat transfer characteristics in addition to its main functions such as rigid fixation properties.

scholarly journals A Study of the Effects of Rain, Snow and Hail on the Atmospheric Electric Field near Ground

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 996
Author(s):  
Athanasios Karagioras ◽  
Konstantinos Kourtidis
Keyword(s):  
Frequency Distribution ◽  
Complex Structure ◽  
Potential Gradient ◽  
Weather Conditions ◽  
The Other ◽  
Fair Weather ◽  
Northern Greece ◽  
Rain Events ◽  
The Impact ◽  
Bounce Back

The purpose of the present study is to investigate the impact of rain, snow and hail on potential gradient (PG), as observed in a period of ten years in Xanthi, northern Greece. An anticorrelation between PG and rainfall was observed for rain events that lasted several hours. When the precipitation rate was up to 2 mm/h, the decrease in PG was between 200 and 1300 V/m, in most cases being around 500 V/m. An event with rainfall rates up to 11 mm/h produced the largest drop in PG, of 2 kV/m. Shortly after rain, PG appeared to bounce back to somewhat higher values than the ones of fair-weather conditions. A decrease in mean hourly PG was observed, which was around 2–4 kV/m during the hail events which occurred concurrently with rain and from 0 to 3.5 kV/m for hail events with no rain. In the case of no drop, no concurrent drop in temperature was observed, while, for the other cases, it appeared that, for each degree drop in temperature, the drop in hourly mean PG was 1000 V/m; hence, we assume that the intensity of the hail event regulates the drop in PG. The frequency distribution of 1-minute PG exhibits a complex structure during hail events and extend from −18 to 11 kV/m, with most of the values in the negative range. During snow events, 1-minute PG exhibited rapid fluctuations between high positive and high negative values, its frequency distribution extending from −10 to 18 kV/m, with peaks at −10 and 3 kV/m.

scholarly journals Possibilities of the Development of Edible Insect-Based Foods in Europe

Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 766
Author(s):  
Magdalena Skotnicka ◽  
Kaja Karwowska ◽  
Filip Kłobukowski ◽  
Aleksandra Borkowska ◽  
Magdalena Pieszko
Keyword(s):  
Material Processing ◽  
Functional Food ◽  
The Other ◽  
Raw Material ◽  
Edible Insects ◽  
Mineral Salts ◽  
Edible Insect ◽  
Alternative Protein ◽  
The World ◽  
The One

All over the world, a large proportion of the population consume insects as part of their diet. In Western countries, however, the consumption of insects is perceived as a negative phenomenon. The consumption of insects worldwide can be considered in two ways: on the one hand, as a source of protein in countries affected by hunger, while, on the other, as an alternative protein in highly-developed regions, in response to the need for implementing policies of sustainable development. This review focused on both the regulations concerning the production and marketing of insects in Europe and the characteristics of edible insects that are most likely to establish a presence on the European market. The paper indicates numerous advantages of the consumption of insects, not only as a valuable source of protein but also as a raw material rich in valuable fatty acids, vitamins, and mineral salts. Attention was paid to the functional properties of proteins derived from insects, and to the possibility for using them in the production of functional food. The study also addresses the hazards which undoubtedly contribute to the mistrust and lowered acceptance of European consumers and points to the potential gaps in the knowledge concerning the breeding conditions, raw material processing and health safety. This set of analyzed data allows us to look optimistically at the possibilities for the development of edible insect-based foods, particularly in Europe.

scholarly journals Turning Base Transceiver Stations into Scalable and Controllable DC Microgrids Based on a Smart Sensing Strategy

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1202
Author(s):  
Miguel Tradacete ◽  
Carlos Santos ◽  
José A. Jiménez ◽  
Fco Javier Rodríguez ◽  
Pedro Martín ◽  
...  
Keyword(s):  
Electricity Market ◽  
Low Cost ◽  
Storage System ◽  
Environmental Parameters ◽  
Weather Conditions ◽  
Energy Storage System ◽  
Electricity Grid ◽  
Dc Microgrids ◽  
Smart Sensing ◽  
Battery Energy

This paper describes a practical approach to the transformation of Base Transceiver Stations (BTSs) into scalable and controllable DC Microgrids in which an energy management system (EMS) is developed to maximize the economic benefit. The EMS strategy focuses on efficiently managing a Battery Energy Storage System (BESS) along with photovoltaic (PV) energy generation, and non-critical load-shedding. The EMS collects data such as real-time energy consumption and generation, and environmental parameters such as temperature, wind speed and irradiance, using a smart sensing strategy whereby measurements can be recorded and computing can be performed both locally and in the cloud. Within the Spanish electricity market and applying a two-tariff pricing, annual savings per installed battery power of 16.8 euros/kW are achieved. The system has the advantage that it can be applied to both new and existing installations, providing a two-way connection to the electricity grid, PV generation, smart measurement systems and the necessary management software. All these functions are integrated in a flexible and low cost HW/SW architecture. Finally, the whole system is validated through real tests carried out on a pilot plant and under different weather conditions.

The Smugglers' Trade: A Neglected Aspect of English Commercial Development

1952 ◽  
Vol 2 ◽  
pp. 131-157 ◽  
Author(s):  
G. D. Ramsay
Keyword(s):  
Eighteenth Century ◽  
Foreign Trade ◽  
Free Trade ◽  
Technical Skill ◽  
The Other ◽  
Raw Material ◽  
Commercial Development ◽  
Illicit Trade ◽  
Modern Times ◽  
Victorian Age

Some share—fluctuating and uncertain, but assuredly significant—of English foreign trade in modern times is to be credited to smugglers, who were ever busy in evading customs regulations and prohibitions. Mere administrative watchfulness and thoroughness could never do more than damp their activities; it was only the triumph of free trade in the early Victorian age that deprived them of their livelihood, and until then they were able to match by increase of cunning and of organization the ever more elaborate network of the customs system—its spies, its coastguards and its cutters as well as its routine officials at the ports. The smuggler flourished right down to the end of the period of protection, despite sporadic seizures by the revenue officers. In the first half of the nineteenth century, French wines, brandies and luxury textiles were being punctually shipped across the Channel in the teeth of prohibitions. In the other direction, we know, for instance, of the existence in the same period of so remarkable á phenomenon as the muslin manufacture of Tarare, near Lyons, which relied for its raw material upon the assured supply of English yarn owled abroad. But it was probably the eighteenth century, when customs regulations were at their most burdensome and complicated, that marked the classic epoch of illicit trade, the period in which the technical skill of both breakers and defenders of the law might earn the highest rewards.

Numerical Analysis of Latent Thermal Energy Storage System With Embedded Thermosyphons

2012 ◽  
Author(s):  
Karthik Nithyanandam ◽  
Ranga Pitchumani
Keyword(s):  
Thermal Conductivity ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Solar Power ◽  
Storage System ◽  
High Energy ◽  
Concentrating Solar Power ◽  
Discharge Performance ◽  
Low Thermal Conductivity

Latent thermal energy storage (LTES) system offers high energy storage density and nearly isothermal operation for concentrating solar power generation. However, the low thermal conductivity possessed by the phase change material (PCM) used in LTES system limits the heat transfer rates. Utilizing thermosyphons to charge or discharge a LTES system offers a promising engineering solution to compensate for the low thermal conductivity of the PCM. The present work numerically investigates the enhancement in the thermal performance of charging and discharging process of LTES system by embedding thermosyphons. A transient, computational analysis of the LTES system with embedded thermosyphons is performed for both charging and discharging cycles. The influence of the design configuration of the system and the arrangement of the thermosyphons on the charge and discharge performance of the LTES installed in a concentrating solar power plant (CSP) is analyzed to identify configurations that lead to improved effectiveness.

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