scholarly journals Conservation of forest based on a fuelwood substitute as well as considering the cultural and spiritual values: an optimal fuelwood harvest model

2020 ◽  
Author(s):  
Polash Banerjee
Keyword(s):  
Energy Content ◽  
Forest Degradation ◽  
High Energy ◽  
Maximum Sustainable Yield ◽  
Comparative Statics ◽  
Forest Growth ◽  
Spiritual Values ◽  
Forest Growth Model ◽  
Liquid Petroleum Gas ◽  
Harvest Model

Abstract Excessive fuelwood harvest is a major cause of deforestation in the developing countries. To mitigate this, various preventive measures have been introduced in different countries. Availability of affordable substitute to the community dependent on the forest for domestic energy consumption may prevent further forest degradation. A stock dependent optimal control model of fuelwood harvest from a natural forest is presented here and comparative statics has been used to show that the presence of a fuelwood substitute will reduce its harvest and increase the forest stock. The model indicates that availability of cheaper and high energy content alternative for fuelwood can substantially reduce fuelwood extraction from a forest. Also, a lower discount rate and higher cultural and spiritual values (CSV) will keep the optimal forest stock close to its carrying capacity and reduce fuelwood harvest. The model reveals that the maximum sustainable yield of forest stock and the ratio of energy content per unit mass of fuel play a central role in the fate of forest stock and level of fuelwood harvest. Empirical example of the Southeast Asian forest growth model along with Liquid Petroleum Gas (LPG) as substitute has been used to illustrate the results. The outcomes of this study can incorporated into forest conservation polices.

Das nachhaltig verfügbare Holznutzungspotenzial im Schweizer Wald

2016 ◽  
Vol 167 (3) ◽  
pp. 162-171 ◽  
Author(s):  
Ruedi Taverna ◽  
Michael Gautschi ◽  
Peter Hofer
Keyword(s):  
National Level ◽  
Reference Value ◽  
Forest Growth ◽  
Long Term Effects ◽  
Management Scenarios ◽  
Additional Time ◽  
Basic Scenario ◽  
Economic Framework ◽  
Forest Growth Model ◽  
New Findings

The sustainably available wood use potential in Swiss forests Based on the most recent simulations created using the Massimo forest growth model, the sustainably available wood use potential in Swiss forests was calculated for five management scenarios for the next three decades as well as for two additional time periods in the future (to monitor the long-term effects). The term “sustainably available wood use potential” covers those wood quantities that could be put on the market, taking into account socio-ecological and economic restrictions on use. The sustainably available wood use potential is provided for production regions, priority functions as well as the assortment and qualities of timber. The previously used factors of the applied “onion” model were checked and modified, if necessary, in order to take new findings and current cost developments into consideration. The calculations for all scenarios come up with a sustainably available wood use potential that is much lower than in earlier investigations. Depending on the scenario and decade, sustainably available wood use potential accounts for less than 50% of the total use potential. The biggest decrease in total use potential was due to economic framework conditions. Turning to Switzerland as a whole, towards the end of the investigation period (2106) those scenarios including a sharp increase in use in the first three decades result in a sustainably available wood use potential that is clearly lower than the reference value used at the beginning of the simulation. In the basic scenario (constant stock) and in the scenario in which the form of management used to date (increasing stock) was simulated, the sustainably available wood use potential at national level remained more or less the same throughout the simulation period, ranging from 5 to 6 million m3 per year.

scholarly journals Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3193
Author(s):  
Ana L. Santos ◽  
Maria-João Cebola ◽  
Diogo M. F. Santos
Keyword(s):  
Energy Content ◽  
Water Electrolysis ◽  
High Energy ◽  
Operating Conditions ◽  
Energy Sources ◽  
Alkaline Water Electrolysis ◽  
Alkaline Water ◽  
New Energy ◽  
Recent Developments ◽  
Cell Components

Environmental issues make the quest for better and cleaner energy sources a priority. Worldwide, researchers and companies are continuously working on this matter, taking one of two approaches: either finding new energy sources or improving the efficiency of existing ones. Hydrogen is a well-known energy carrier due to its high energy content, but a somewhat elusive one for being a gas with low molecular weight. This review examines the current electrolysis processes for obtaining hydrogen, with an emphasis on alkaline water electrolysis. This process is far from being new, but research shows that there is still plenty of room for improvement. The efficiency of an electrolyzer mainly relates to the overpotential and resistances in the cell. This work shows that the path to better electrolyzer efficiency is through the optimization of the cell components and operating conditions. Following a brief introduction to the thermodynamics and kinetics of water electrolysis, the most recent developments on several parameters (e.g., electrocatalysts, electrolyte composition, separator, interelectrode distance) are highlighted.

Autothermal biodrying of municipal solid waste with high moisture content

2010 ◽  
Vol 64 (2) ◽  
Author(s):  
Agnieszka Zawadzka ◽  
Liliana Krzystek ◽  
Stanisław Ledakowicz
Keyword(s):  
Moisture Content ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Energy Content ◽  
Plastic Material ◽  
Initial Moisture Content ◽  
Tubular Reactor ◽  
Calorific Value ◽  
High Energy ◽  
Total Capacity

AbstractTo carry out autothermal drying processes during the composting of biomass, a horizontal tubular reactor was designed and tested. A biodrying tunnel of the total capacity of 240 dm3 was made of plastic material and insulated with polyurethane foam to prevent heat losses. Municipal solid waste and structural plant material were used as the input substrate. As a result of autothermal drying processes, moisture content decreased by 50 % of the initial moisture content of organic waste of about 800 g kg−1. In the tested cycles, high temperatures of biodried waste mass were achieved (54–56°C). An appropriate quantity of air was supplied to maintain a satisfactory level of temperature and moisture removal in the biodried mass and high energy content in the final product. The heat of combustion of dried waste and its calorific value were determined in a calorimeter. Examinations of pyrolysis and gasification of dried waste confirmed their usefulness as biofuel of satisfactory energy content.

scholarly journals Model-Based Estimation of Amazonian Forests Recovery Time after Drought and Fire Events

Forests ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 8
Author(s):  
Bruno L. De Faria ◽  
Gina Marano ◽  
Camille Piponiot ◽  
Carlos A. Silva ◽  
Vinícius de L. Dantas ◽  
...  
Keyword(s):  
Recovery Time ◽  
Regional Scale ◽  
Forest Growth ◽  
Forest Recovery ◽  
Fire Intensity ◽  
Natural Ecosystems ◽  
Spatial And Temporal Patterns ◽  
Southeastern Part ◽  
Forest Growth Model ◽  
Carbon Losses

In recent decades, droughts, deforestation and wildfires have become recurring phenomena that have heavily affected both human activities and natural ecosystems in Amazonia. The time needed for an ecosystem to recover from carbon losses is a crucial metric to evaluate disturbance impacts on forests. However, little is known about the impacts of these disturbances, alone and synergistically, on forest recovery time and the resulting spatiotemporal patterns at the regional scale. In this study, we combined the 3-PG forest growth model, remote sensing and field derived equations, to map the Amazonia-wide (3 km of spatial resolution) impact and recovery time of aboveground biomass (AGB) after drought, fire and a combination of logging and fire. Our results indicate that AGB decreases by 4%, 19% and 46% in forests affected by drought, fire and logging + fire, respectively, with an average AGB recovery time of 27 years for drought, 44 years for burned and 63 years for logged + burned areas and with maximum values reaching 184 years in areas of high fire intensity. Our findings provide two major insights in the spatial and temporal patterns of drought and wildfire in the Amazon: (1) the recovery time of the forests takes longer in the southeastern part of the basin, and, (2) as droughts and wildfires become more frequent—since the intervals between the disturbances are getting shorter than the rate of forest regeneration—the long lasting damage they cause potentially results in a permanent and increasing carbon losses from these fragile ecosystems.

Net energy efficiencies of Holstein, Jersey and Holstein-Jersey F1-crosses

2001 ◽  
Vol 72 (2) ◽  
pp. 335-342 ◽  
Author(s):  
R. Schwager-Suter ◽  
C. Stricker ◽  
D. Erdin ◽  
N. Künzi
Keyword(s):  
Body Weight ◽  
Body Condition ◽  
Fixed Effects ◽  
Energy Content ◽  
High Energy ◽  
Repeated Measurements ◽  
Low Energy ◽  
Body Tissue ◽  
Net Energy ◽  
Tissue Change

Abstract Net energy efficiencies were calculated from data of an experimental herd with respect to type of cow, lactation number, stage of lactation and diet. The trial consisted of 71 Holstein-Friesians, 71 Jerseys and 71 Holstein-Jersey F1-crosses in 1st, 2nd and > 2nd lactation. Data were collected during 210 days of lactation, from calving to week 30 and included total dry matter intake, energy content of foods, milk yield, milk solids, body weight, body condition scores and several body measurements. The cows were divided into four feeding groups : high and low energy content of roughage as well as high and low proportion of concentrates. Net energy efficiency was calculated as the ratio of milk energy to total net energy intake after subtracting energy utilized for maintenance and body tissue change. Body tissue change was calculated either via body-weight changes or body condition-score changes. Due to the distribution of the efficiencies being skewed, efficiencies were transformed applying a Box-Cox transformation. Transformed net energy efficiencies were analysed using a repeated measurements design considering the sequential nature of the observations. Mixed models with a compound symmetry structure for the variance components were applied. Final models contained the fixed effects of type, lactation number, feeding group and the covariates week of lactation and its square. Holstein-Jersey crosses were more efficient than purebreds, second lactation cows were least efficient, cows given low energy roughage and a lower proportion of concentrates were more efficient than cows on the other diets. Least efficient were the cows belonging to the high energy roughage and higher proportion of concentrates group. The coefficients of determination of the final models were between 0·357 and 0·492.

Hydrogen Generation in an Annular Micro-Reactor: an Experimental Investigation of Water Splitting Reaction Using Aluminum in Presence of Potassium Hydroxide

2018 ◽  
Vol 17 (2) ◽  
Author(s):  
Shyam P. Tekade ◽  
Diwakar Z. Shende ◽  
Kailas L. Wasewar
Keyword(s):  
Water Splitting ◽  
Potassium Hydroxide ◽  
Hydrogen Generation ◽  
Energy Content ◽  
Average Rate ◽  
High Energy ◽  
Low Flow ◽  
Flow Rates ◽  
Metal Aluminum ◽  
Micro Reactor

Abstract Hydrogen is one of the important non-conventional energy sources because of its high energy content and non-polluting nature of combustions. The water splitting reaction is one of the significant methods for hydrogen generation from non-fossil feeds. In the present paper, the hydrogen generation has been experimentally investigated with water splitting reaction using metal aluminum in presence of potassium hydroxide as an activator under flow conditions. The rate of hydrogen generation was reported in the annular micro- reactor of 1 mm annulus using various flow rates of aqueous 0.5 N KOH ranging from 1 ml/min to 10 ml/min. The complete conversion of aluminum was observed at all the flow rates of aqueous KOH. The hydrogen generation rate was observed to depend on the flow rate of liquid reactant flowing through the reactor. At 1 ml/min of 0.5 N KOH, hydrogen generates at an average rate of 3.36 ml/min which increases to 10.70 ml/min at 10 ml/min of aqueous KOH. The Shrinking Core Model was modified for predicting the controlling mechanism. The rate of hydrogen generation was observed to follow different controlling mechanisms on various time intervals at low flow rates of aqueous KOH. It was observed that chemical reaction controls the overall rate of hydrogen generation at higher flow rates of aqueous KOH.

Yields Performance of Automotive Paint Sludge via Microwave Assisted Pyrolysis

2014 ◽  
Vol 548-549 ◽  
pp. 191-195 ◽  
Author(s):  
Zakiuddin Januri ◽  
Norazah Bt Abdul Rahman ◽  
Siti Shawalliah Idris ◽  
Sharmeela Matali ◽  
Shareena Fairuz Abdul Manaf
Keyword(s):  
Energy Content ◽  
Power Level ◽  
Liquid Product ◽  
Product Yield ◽  
High Energy ◽  
Microwave Assisted ◽  
Automotive Paint ◽  
Optimum Weight ◽  
Paint Sludge

This paper reported on the product yield of automotive paint sludge via microwave assisted pyrolysis. By having an optimum weight sample loading and power level at 500g and 1000W respectively, optimum product in terms of liquid yields has been obtained. This desired liquid product comprised hydrocarbon material since it contains oil layer and almost 40% of the product can be recovered from the automotive paint sludge with an optimum microwave parameter. Furthermore, the liquid product has a potential to be used as fuel since it exhibit high energy content at 22.6 MJ/kg.

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