Energetic Consumption Research Articles

Design of buildings shape and energetic consumption

This work aims at relating the heating consumption of the buildings with their shape. This information is dedicated to the architects and engineers. At the beginning of the project, they need global information enabling them to find economical solutions as for energy consumption. First of all, a parameter that has been chosen to characterize the shape of the buildings is introduced. The selection of this coefficient is grounded on the necessary simplicity of its use by conceivers. Thus, the shape coefficient is defined as the ratio between the external skin surfaces and the inner volume of the building. Then, the sample of the studied buildings is described. Fourteen buildings have been chosen according to their varieties in shapes and their representativeness in current constructions. The calculation code used to evaluate the heating consumption is briefly described. This code operates the method of weighting factors. The method is quick and well adapted to the study as the 14 buildings are conceived from the same basic cell. The results show that the energetic consumption is inversely proportional to the compactness (weak shape coefficient) in case of cold severe and scarcely sunny winters. However, it can't be applied in case of mild climates, which leads to no recommendation of compactness.

Comparison between trolley-bus and tram vehicles: performances and consequent environmental impact

The Public Transportation System is now rediscovering the use of trams due to ever increasing pollution problems. The entire system transports from 2000 to 15000 p/hd, and uses either the right of way (ROW) or the light rail transit (LRT). Nevertheless a new generation of articulated electric trolley buses (ETB) are becoming an attractive option. The ETB is bimodal, or rather, it has a double traction energy supply. Its engine-electric generator unit allows it to disconnect from the Overhead Catenary System (OCS) and continue operating as before. This paper compares an ETB transportation system, which uses vehicles holding 155 p, with the currently tram system used in Rome, which uses vehicles holding 180 or 260 p. Based on the same passenger-flow, this comparison evaluates: which system, is more cost effective for a company, reduces waiting time at bus stops, provides less environmental impact (noise, vibrations, and visual one). These steps will be followed: data collection, energetic consumption simulation program, transportation costs definition, simulation model on tramway network. The Transport Costs Analysis develops a model based on overall total cost, including the complete construction of both the tram and ETB systems on the present network. Costs include personnel, traction materials, vehicles, infrastructures and plant maintenance and amortization. Costs are calculated per vehicle km, per place km, per km run by the whole fleet on a line.

Division of labour and seasonality in the ant Leptothorax albipennis: worker corpulence and its influence on behaviour

We address the organization of workers in social insect societies. We distinguish between changes in behavioural role over the nurse to forager role sequence, which may depend on changes in physiology, and potentially more rapid changes of task within role. We investigated the association between role and nutrient status in the ant Leptothorax albipennis. Worker lipid stores were quantified using a new body size-controlled method, and were related to worker behaviour. Worker lipid stores were evenly distributed amongst colony members at the end of winter, splitting rapidly into two distinct modes (replete nurses and lean foragers) in spring. The proportion of lean foragers increased throughout spring and summer, until most colonies contained only workers of this type. Callow workers then eclosed with intermediate lipid stores. We developed a computer vision system that tracks all nest ants to extract detailed behaviour of individuals of known lipid stores. Lipid storage was negatively correlated with a worker's foraging propensity, and with measures of spatial occupation in the nest and of activity. Different colonies showed a similar quantitative correlation between lipid stores and behavioural role, suggesting that lipid stores were not only correlated with the relative organization of individuals within each nest, but may also have influenced their absolute role. We reviewed the literature and found evidence that nutrient status influences role predisposition in social insect workers. We conclude that the distribution of worker roles may be linked to the balance between foraging income and energetic consumption within the colony directly via worker nutrient status.

Acute and sublethal effects of a non-ionic surfactant, Genapol OXD-080, on mosquitofish Gambusia holbrooki (Girard).

Application of the biodegradable non-ionic surfactant Genapol OXD-080, a fatty alcohol polyglycol ester, in rice paddies has been considered as a method to mitigate damage caused by the Louisiana red swamp crayfish, Procambarus clarkii, to rice crops. The damages are a consequence of crayfish digging activities. The acute and sublethal effects of Genapol on a non-target key species were examined to assess the potential risk of contaminating the irrigation channels following its application in the rice paddies. Mosquitofish, Gambusia holbrooki, due to its abundance in irrigation channels, and because it is a predator with an intermediate position in the food chain, was selected as the key non-target species. The LC50 value for Genapol to mosquitofish was 2.9 mg l-1, a value 17.2 times lower than the Genapol concentration needed to decrease crayfish digging activity (50 mg l-1). For sublethal tests, three biological parameters were considered in laboratory experiments with mosquitofish: respiratory metabolism, food (energetic) consumption, and clutch survival. A significant decrease in the resting metabolism of mosquitofish was observed, even when Genapol exposure concentrations were very low (e.g., 0.75 mg l-1). Thus, oxygen consumption rates of mosquitofish are strongly affected by to the presence of this surfactant in water. In contrast, mosquitofish food consumption and clutch survival seemed not to be affected by sub-lethal concentrations of Genapol. Yet, sub-lethal effect concentrations for mosquitofish are so much lower than the concentration necessary to decrease significantly crayfish activity, we conclude that there is a reasonable potential risk of damaging local mosquitofish populations if contamination of the irrigation channels with Genapol occurs.

Muscle ATP synthesis and utilisation, balanced during flow-induced increase of respiration.

To investigate the control of cell energetic metabolism, creatine charge, ATP/ADP ratio and oxygen consumption (as indicators of an energetic status, the balance between ATP synthesis and degradation and the aerobic ATP turnover, respectively) were evaluated in the rat gracilis muscle, perfused-superfused in vitro. During the perfusion rate of 70 microl/min the ATP/ADP ratio, as well as the creatine charge are kept at the in vivo level. With the decrease of the rate toward 54 microl/min (of an abundant oxygen delivery), the values of both parameters are lower than levels in vivo. With the increase of the rate up to 100 microl/min, both parameters are kept at the in vivo level, when respiration increases by 125%. The data demonstrate the 'unmatched' control of ATP utilisation and synthesis steady rates during the low perfusion rate; during the increasing steady ATP turnover following the increased perfusion rate, the two fluxes are strikingly 'matched', i.e. precisely balanced.

Changes in female cognitive performance after energetic drink consumption: A preliminary study

1. 1. A group of males and a group of females consumed either no drink, a placebo or a caffeinecontaining energy drink. Subjects were requested to perform a simple reaction times task and a go-no-go reaction times task. 2. 2. Males responded significantly faster than females. The effect of drink was apparent only for females performing the go-no-go task, while it was undetectable in female simple reaction times and in males. 3. 3. A mild effect due to the drink, but not to the placebo, appears only when the task requires a certain degree of cognitive processing and is evident only in subjects possibly adopting a cognitive strategy that allows an improvement of performance.

Intermediary agricultural energetics: a case study of solar energy linkage with Chinese working cattle

The solar energy impinging upon the agricultural fields of a single village in Shandong province of the People's Republic of China was traced through the crop residues to the cattle that were employed to cultivate the crops. The amount of solar energy captured by the total plant biomass at harvest time (expressed as a percentage of the total incident solar insolation) was 0.96% for wheat, 0.94% for corn and 0.70% for cotton. Over a 1-year period cattle consumed 7.42% of the energy contained in the wheat plant, 5.10% of the cotton plant, and 365 of the corn plant. Less than 1% (0.92%) of the total yearly energetic consumption of the cattle was devoted toward providing power for agricultural work. Thirty-one percent of the cattle energy consumption was returned to the soil as dung. Milk and beef were not consumed by humans in this village. Corn provided 67% of the total energy requirements for this cattle population. It is proposed that this more complete analysis of interttrophic energetic exchange offers certain advantages over the more traditional energetic focus of human targeted products. Subtle inter-relationships are revealed that might otherwise be difficult to recognize in cross-cultural analyses.

Influence of the β-adrenergic agonist cimaterol on energetic efficiency and oxygen consumption in liver tissue of growing lambs

The effects of dietary cimaterol on energetic efficiency and liver oxygen consumption were evaluated using 14 wether lambs. Lambs were fed at a low intake (491 kJ kg−0.75 d−1 metabolizable energy (ME)) followed by a high intake (919 kJ ME kg−0,75 d−1). Five control animals received a pelleted alfalfa diet and five received a diet in which cimaterol was added at a level of 10.9 mg kg−1 dry matter. Four additional animals received no cimaterol at the low intake level and 10.9 mg kg−1 dry matter at the high intake. Indirect calorimetry measurements were conducted over a 24-h period on day 22 at each feeding level. Digestibility of dry matter and energy were not affected by cimaterol treatment. Methane production as a percentage of gross and digestible energy intake was increased (P = 0.04) 19% by cimaterol treatment at the 1.1 × M feeding level. Heat production was not affected by cimaterol treatment. Maintenance requirements (kJ ME kg−0.75 d−1) ranged from 314 to 438 for control and from 402 to 458 for cimaterol-treated lambs, depending upon the method of estimation. Energy costs of protein accretion (kJ ME kJ−1 deposited) in control lambs, estimated by a complete multiple regression procedure, by a multiple regression procedure following estimation of maintenance requirements by a semilog-linear procedure, and by assuming a constant efficiency for fat synthesis, were 4.85, 2.54 and 2.91, respectively. Corresponding values for cimaterol I lambs were 2.64, 1.65 and 1.98. Using estimates of protein synthesis obtained from radiolabelled leucine kinetics, the cost of protein synthesis was estimated as 1.25 kJ ME kJ−1 protein synthesized. Estimated energy costs of fat accretion were 0.56–1.13 and 0.94–1.30 kJ ME kJ−1 for control and cimaterol I lambs, respectively. Na+, K+-ATPase-dependent oxygen consumption rate of liver tissue tended (P = 0.06) to be reduced by 20% for cimaterol I compared with control lambs. Key words: Lambs, cimaterol, energy efficiency, protein, fat, Na+, K+-ATPase

Oxygen transfer during batch cultivation in an airlift tower fermentor

Oxygen transfer was studied in an airlift tower fermentor with motionless mixers (Kenics type). The intensity of oxygen transfer was characterized by its volumetric mass transfer coefficient, kLa, which was determined by the balance method. Experimental data of kLa were described by correlation equation and compared with results obtained for the airlift fermentor without motionless mixers with respect to energetic consumption. In addition, growth characteristics of the yeast culture Turulopsis ethanolitolerans cultivated on ethanol were also investigated.

Etnoarqueología del combustible: una aproximación arqueológica a las interacciones sociales entre bosques, árboles y personas

En este artículo expongo algunas reflexiones en torno al uso de la etnoarqueología como escenario para el estudio de las relaciones entre los humanos y su entorno. Partiendo de una revisión bibliográfica (que no pretende ser exhaustiva) y de diversos casos de estudio de mi trabajo de campo en Ghana y Guinea Equatorial, discuto como las relaciones entre personas y árboles para el uso de la madera – leña – como combustible constituye una arena social de interacción entre humanos y no-humanos. Analizo como estas prácticas cotidianas de aprovisionamiento y consumo energético en el bosque, lejos de ser prácticas monótonas y alejadas de toda creatividad social, se integran y participan de la materialización de las diversas formas en que las sociedades humanas perciben el entorno y lo socializan mediante la acción material sobre éste. De esta forma, se evidencian algunas discusiones que permiten (i) generar aproximaciones arqueológicas a este tipo de cuestiones relacionadas con las interacciones entre naturaleza y cultura; e (ii) integrar perspectivas, aproximaciones, prácticas y narrativas entre las llamadas arqueología científica (en especial referencia a la antracología, disciplina encargada del estudio de restos materiales de árboles y arbustos, carbón y madera, en yacimientos arqueológicos) y arqueología teórica o antropológica.

CONSIDERATIONS ON RECYCLING POSSIBILITIES OF AGRO-INDUSTRIAL WASTES BY ANAEROBIC DIGESTION TREATMENT

In our country, the developments of the measures for the prevention of the environmental pollution are aligning to the UE Directives. The costs for the treatment of the water wastes are continuously increasing, following to the also increasing of the investments costs. Therefore it is necessary to accord attention for the alternatives of cleaning, treating, respective recycling of the agro-industrial wastes and their reintroduction in the natural circuit.
 At the processing of the food results wastes with high organic charge. The effluents form the processing of dairy products, sugar, starch, beer yeasts as well as breweries or distilleries are getting fast into acids fermentation, finally resulting organic acids. Such process water wastes can be released in the canalization by dilution or by a suitable treating. As an example, for the distillery wastes (distillery slops) with a high dry matter contents (4-20%), the waste water treatment plant shall be designed properly (with mechanical separation step and biological treatment) to ensure the capacity of purifying according to the high flow and increased concentration, due to the high CBOD5 concentration. The treatment of such water wastes can be realized with aerobic processes, which suppose a high energetic consumption. While in the aerobic purifying processes 50 % of the CBOD5 is involved in the forming of biomass and slurry in excess, in the anaerobic treatment processes (anaerobic or methane digestion) a high part of the substrate (until 70 %) is metabolized through the metabolic transformation of bacterial flora, with production of biogas. Therefore, the concentrated water wastes, with potential for the energy production could offer a possibility of energy replacement in the own processing units.
 The paper presents a review of the anaerobic digestion for different wastes from the agro-industrial processing and their potential for the biogas production. There are presented possibilities of mixture, respectively of co-digestion of different wastes the agro-industrial processing with other wastes from the agriculture (from cereals processing, biomass, manure etc). Simultaneously biogas plants from the praxis with functioning characteristics are presented.