scholarly journals The role of cover and pattern of installed resource sinks in the recovery of degraded patchy drylands

2020 ◽  
Author(s):  
Angeles Garcia Mayor ◽  
Paul Berghuis ◽  
Max Rietkerk ◽  
Mara Baudena
Keyword(s):  
High Efficiency ◽  
Low Cost ◽  
Field Work ◽  
Higher Plant ◽  
Small Cover ◽  
Plant Densities ◽  
Complete Failure ◽  
Materials Used ◽  
Field Works

<p>A low-cost restoration in patchy drylands aiming at recovering the ability of the ecosystem to capture and store water and nutrients is the installation of obstructions to break runoff pathways and retain these resources (hereafter, resource sinks). Field works in drylands worldwide have studied how the effectiveness of this action depends on the materials used to build the obstructions. However, the spatial pattern attributes of the resource sinks can also affect the effectiveness of the restoration and has not yet been investigated. In this work, we cover this knowledge gap by using a well-known dryland model to investigate how different initial amounts of cover and spatial distribution of installed resource sinks (i.e., random vs. regular) affects the recovery of the system. In agreement with field-work studies, our model results confirm that the installation of resource sinks can restore degraded drylands that are not able to recover naturally. More importantly, we found that a very small cover of resource sinks was sufficient to trigger the recovery of vegetation, while a high cover could lead to a complete failure of vegetation recovery. This was found for both random and regular distributions of resource sinks. However, a distribution similar to that of vegetation in the reference healthy system (i.e., regular distribution in our study system) was more effective: higher plant densities were reached for a given initial cover of resource sinks. Given the high efficiency of low covers of resource sinks suggested by our work, combined with the low-cost materials needed, the installation of resource sinks in severely degraded drylands has the potential to be a key contributor to the large restoration efforts needed to achieve land-degradation neutrality in the coming decades, particularly in developing countries.</p>

The Role of Drop Shipping in E-Commerce

2021 ◽  
Vol 17 (4) ◽  
pp. 54-72
Author(s):  
Brahami Menaouer ◽  
Semaoune Khalissa ◽  
Mohammed El Amine Belayachi ◽  
Benslimane Amine
Keyword(s):  
Economic Development ◽  
Exploratory Study ◽  
High Efficiency ◽  
Low Cost ◽  
New Technology ◽  
Industrial Sectors ◽  
New Models ◽  
Huge Impact ◽  
Structured Questionnaire

During the recent years, e-commerce has been constantly growing in various industrial sectors. E-commerce has also changed the buying pattern of customers. E-commerce is a concept that has gained enormous popularity in recent decades. There are a multitude of variants and strategies of e-commerce such as drop shipping, which is renowned for its low cost and high efficiency. However, e-commerce is a new technology that is growing rapidly. It has the ability to create a truly global digital economy. In this research paper, the authors study the state of the drop shipping market for e-commerce in Algeria and the possibility to introduce new models by analyzing different aspects that can have a huge impact on the evolution of drop shipping in e-commerce in order to promote economic development in Algeria. To develop a better understanding, an exploratory study via a structured questionnaire intended for the general Algerian public drop shipper market was carried out.

scholarly journals Wheat Straw Biochar as a Specific Sorbent of Cobalt in Soil

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2462 ◽  
Author(s):  
Agnieszka Medyńska-Juraszek ◽  
Irmina Ćwieląg-Piasecka ◽  
Maria Jerzykiewicz ◽  
Justyna Trynda
Keyword(s):  
Wheat Straw ◽  
Contaminated Soils ◽  
High Efficiency ◽  
Dominant Role ◽  
Low Cost ◽  
Material Efficiency ◽  
Ft Ir ◽  
Heavy Metal Adsorbent

There is an urgent need to search for new sorbents of pollutants presently delivered to the environment. Recently biochar has received much attention as a low-cost, highly effective heavy metal adsorbent. Biochar has been identified as an efficient material for cobalt (Co) immobilization from waters; however, little is known about the role of Co immobilization in soil. Hence, in this study, a batch experiment and a long-term incubation experiment with biochar application to multi-contaminated soil with distinct properties (sand, loam) were conducted to provide a brief explanation of the potential mechanisms of Co (II) sorption on wheat straw biochar and to describe additional processes that modify material efficiency for metal sorption in soil. The soil treatments with 5% (v/w) wheat straw biochar proved to be efficient in reducing Co mobility and bioavailability. The mechanism of these processes could be related to direct and indirect effects of biochar incorporation into soil. The FT-IR analysis confirmed that hydroxyl and carboxyl groups present on the biochar surface played a dominant role in Co (II) surface complexation. The combined effect of pH, metal complexation capacity, and the presence of Fe and Mn oxides added to wheat straw biochar resulted in an effective reduction of soluble Co (II), showing high efficiency of this material for cobalt sorption in contaminated soils.

scholarly journals Electrode Materials for Supercapacitors in Hybrid Electric Vehicles: Challenges and Current Progress

2022 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Sivakumar Rajagopal ◽  
Rameez Pulapparambil Vallikkattil ◽  
M. Mohamed Ibrahim ◽  
Dimiter Georgiev Velev
Keyword(s):  
Electric Vehicles ◽  
Hybrid Electric Vehicles ◽  
Electrode Materials ◽  
High Efficiency ◽  
Low Cost ◽  
Current Collector ◽  
Manufacturing Strategy ◽  
Promising Alternative ◽  
Hybrid Electric ◽  
Materials Used

For hybrid electric vehicles, supercapacitors are an attractive technology which, when used in conjunction with the batteries as a hybrid system, could solve the shortcomings of the battery. Supercapacitors would allow hybrid electric vehicles to achieve high efficiency and better power control. Supercapacitors possess very good power density. Besides this, their charge-discharge cycling stability and comparatively reasonable cost make them an incredible energy-storing device. The manufacturing strategy and the major parts like electrodes, current collector, binder, separator, and electrolyte define the performance of a supercapacitor. Among these, electrode materials play an important role when it comes to the performance of supercapacitors. They resolve the charge storage in the device and thus decide the capacitance. Porous carbon, conductive polymers, metal hydroxide, and metal oxides, which are some of the usual materials used for the electrodes in the supercapacitors, have some limits when it comes to energy density and stability. Major research in supercapacitors has focused on the design of stable, highly efficient electrodes with low cost. In this review, the most recent electrode materials used in supercapacitors are discussed. The challenges, current progress, and future development of supercapacitors are discussed as well. This study clearly shows that the performance of supercapacitors has increased considerably over the years and this has made them a promising alternative in the energy sector.

scholarly journals The role of Debrecen maize hybrids in competitive production

2006 ◽  
pp. 19-21
Author(s):  
Barnabás Forgács
Keyword(s):  
Plant Density ◽  
Higher Plant ◽  
Maize Hybrids ◽  
Term Experiment ◽  
Average Precipitation ◽  
Long Term Experiment ◽  
Plant Densities ◽  
Set Up

I examined the effects of plant density and fertilisation on the yield of the maize hybrid Debreceni 377 SC, developed by the Agrárgazdaság Ltd., using the 3 year data sequence of a long term experiment set up at the Látókép experimental station of DU Center for Agricultural Sciences in years with average precipitation supply.Based on the evaluation of my research results, I found that the application of higher plant densities was more favourable in years with average or higher than average precipitation supply. During the examination of fertilisation effects, it was verified that surplus yield was realised in most cases where smaller fertilisation dosage, 120 kg per hectare active substance was applied.

Current State and Future Perspectives of Carbon Based Materials in the Environment: Fate and Application

2020 ◽  
Vol 14 ◽  
Author(s):  
Marijana Kragulj Isakovski ◽  
Jelena Beljin ◽  
Jelena Tričković ◽  
Srđan Rončević ◽  
Snežana Maletić
Keyword(s):  
High Efficiency ◽  
Low Cost ◽  
Soil Improvement ◽  
Water And Wastewater Treatment ◽  
New Approach ◽  
Current State ◽  
Material Usage ◽  
Adsorption Processes ◽  
Materials Used ◽  
Carbon Based

Background: Environmental pollution has been a recognized problem for human health and the ecosystem. Remediation is usually costly and time-consuming, so researchers' attention has been drowning to develop and use new materials. This review aims to summarize the recent development of carbon-based materials used for environmental management. Method: We conducted a detailed analysis of available literature based on the Web of Science database. In the third part of the manuscript are given some of the recent patents on carbon based materials. The corresponding papers were carefully evaluated. Results: More than one hundred and ninety papers were included in section literature. Based on the available literature it can be observed an increasing trend in carbon-based material usage. These materilas are used in resolving environmental issues: adsorbents in water and wastewater treatment; precursor of catalysts, soil improvement, waste management, climate change mitigation, electrochemical energy storage and soil remediation adsorption processes. Although it is manly new approach considered as environmentally friendly, there are finding, observation, negative aspects, and conclusion that must be taken into consideration. Conclusion: The findings of this review confirm that many factors must be considered when carbon-based materials are used. At the same time, this review aims to emphasize development trends in providing a useful guide to design and fabricate high-efficiency and low-cost carbon materials.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

Brownstock washing: A review of the literature

TAPPI Journal ◽  
2014 ◽  
Vol 13 (1) ◽  
pp. 9-19 ◽  
Author(s):  
RICARDO B. SANTOS ◽  
PETER W. HART
Keyword(s):  
High Efficiency ◽  
Black Liquor ◽  
Material Balance ◽  
Kraft Pulping ◽  
Wash Water ◽  
Pulp Fibers ◽  
Kraft Process ◽  
Cooking Process ◽  
Materials Used ◽  
Entrapped Air

Brownstock washing is a complex, dynamic process in which dirty wash water or weak black liquor (dissolved organic and inorganic material obtained from the pulp cooking process) is separated from pulp fibers. The use of material balance techniques is of great importance to identify potential problems and determine how well the system is operating. The kraft pulping industry was the first known to combine pulp washing with the recovery of materials used and produced in the wood cooking process. The motivation behind materials recovery is economic, and more recently, environmentally driven. The chemicals used in the kraft process are expensive as compared to those used in the sulfite process. For the kraft process to be economically viable, it is imperative that a very high percentage of the cooking chemicals be recovered. To reach such high efficiency, a variety of washing systems and monitoring parameters have been developed. Antifoam additives and processing aids have also played an important role in increasing washing effectiveness. Antifoam materials help attain washing effectiveness by preventing entrapped air from forming in the system, which allows for an easier, unimpeded flow of filtrate through the screens and washers.

Calculations used for assessment of rapid maxillary expansion

ORL ro ◽  
2016 ◽  
Vol 1 (1) ◽  
pp. 24-26
Author(s):  
Ruxandra Bartok ◽  
Bogdan Dimitriu Dimitriu ◽  
Constantin Vârlan ◽  
Radu Stanciu ◽  
Georgiana Moldoveanu ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Elasticity Modulus ◽  
Rapid Maxillary Expansion ◽  
Laboratory Animals ◽  
Maxillary Expansion ◽  
Literature Reference ◽  
Bone Changes ◽  
Upper Jaw ◽  
Materials Used

Rapid maxillary expansion is defined as the release of medio-palatine suture using an orthopedic forces. The role of this procedure is to expand  the upper jaw in order to achieve the  broadening of the upper arch. This study was initiated to quantify the effects of disjunction and post- treatment bone changes, after an adequate contention which lasted for three weeks. This study  is  carried on laboratory animals (common breed rabbit) to determine tensile strength and the elasticity modulus of  biological materials  used in orthdodontics. The results of the study are consistent with those reported in the literature reference.  

Improvement of Ti/RuO2–IrO2 Anode Lifetime and Electrocatalytical Properties by Using an Eco-Friendly Thermal Decomposition Method Using Polyvinyl Alcohol as Solvent

2019 ◽  
Author(s):  
Charlys Bezerra ◽  
Géssica Santos ◽  
Marilia Pupo ◽  
Maria Gomes ◽  
Ronaldo Silva ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Polyvinyl Alcohol ◽  
High Efficiency ◽  
Electrochemical Impedance ◽  
Pechini Method ◽  
Low Cost ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Calcination Temperatures ◽  
Service Lifetime

<p>Electrochemical oxidation processes are promising solutions for wastewater treatment due to their high efficiency, easy control and versatility. Mixed metal oxides (MMO) anodes are particularly attractive due to their low cost and specific catalytic properties. Here, we propose an innovative thermal decomposition methodology using <a>polyvinyl alcohol (PVA)</a> as a solvent to prepare Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes. Comparative anodes were prepared by conventional method employing a polymeric precursor solvent (Pechini method). The calcination temperatures studied were 300, 400 and 500 °C. The physical characterisation of all materials was performed by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy, while electrochemical characterisation was done by cyclic voltammetry, accelerated service lifetime and electrochemical impedance spectroscopy. Both RuO<sub>2</sub> and IrO<sub>2</sub> have rutile-type structures for all anodes. Rougher and more compact surfaces are formed for the anodes prepared using PVA. Amongst temperatures studied, 300 °C using PVA as solvent is the most suitable one to produce anodes with expressive increase in voltammetric charge (250%) and accelerated service lifetime (4.3 times longer) besides reducing charge-transfer resistance (8 times lower). Moreover, the electrocatalytic activity of the anodes synthesised with PVA toward the Reactive Blue 21 dye removal in chloride medium (100 % in 30 min) is higher than that prepared by Pechini method (60 min). Additionally, the removal total organic carbon point out improved mineralisation potential of PVA anodes. Finally, this study reports a novel methodology using PVA as solvent to synthesise Ti/RuO<sub>2</sub>–IrO<sub>2</sub> anodes with improved properties that can be further extended to synthesise other MMO compositions.</p>

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