scholarly journals Factors Affecting the Chipping Operation Based on the Screen Size of the Drum Chipper

Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 1029 ◽  
Author(s):  
Yun-Sung Choi ◽  
Min-Jae Cho ◽  
Seung-Ho Paik ◽  
Ho-Seong Mun ◽  
Dae-Hyun Kim ◽  
...  
Keyword(s):  
Particle Size ◽  
Renewable Energy ◽  
New Technologies ◽  
Forest Biomass ◽  
Wood Chip ◽  
Utilization Efficiency ◽  
Screen Size ◽  
Drying Time ◽  
Productivity Cost ◽  
Factors Affecting

Forest biomass has recently been highlighted as a renewable energy source in South Korea. As the Renewable Energy Certificate weight has been revised to encourage the use of forest biomass for energy production, forest operations have focused on the development of new technologies and harvesting methods for the extraction and utilization of forest biomass. This study examined the application of a drum chipper to forest biomass and analyzed the effects of screen size (40, 50, 65, and 80 mm) on productivity, cost, and particle size distribution. When the screen size was 40 mm to 65 mm, the chipping productivity improved by up to 3.6 times, the fuel consumption decreased by up to 29.7%, and the chipping cost was reduced by up to 31.9%. The fines content tended to decrease with an increase in screen size. The size of woodchips was less than 100 mm in length and ranged from 10 to 63 mm. The 65 mm screen was the most effective (e.g., producing optimal wood chip size at an acceptable production rate) for the chipping operation. Harvesting methods and drying time are also important factors that determine the utilization efficiency of forest biomass. Therefore, further research should be focused on the effect of moisture content on chipping productivity, power required, and fine particle size in forest biomass productions.

Clinical trials — the personal perspective of the research physician?

2020 ◽  
Vol 75 (3) ◽  
pp. 256-263
Author(s):  
Maria Y. Egorova ◽  
Irina A. Shuvalova ◽  
Olga I. Zvonareva ◽  
Igor D. Pimenov ◽  
Olga S. Kobyakova ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Medical Care ◽  
New Technologies ◽  
Healthcare Providers ◽  
Study Drug ◽  
Well Being ◽  
Personal Perspective ◽  
Public And Private ◽  
Factors Affecting ◽  
To Receive

Background. The organization of clinical trials (CTs) requires the participation and coordination of healthcare providers, patients, public and private parties. Obstacles to the participation of any of these groups pose a risk of lowering the potential for the implementation of CTs. Researchers are a key human resource in conducting of CT. Their motivation for participation can have a significant impact on the recruitment and retention of patients, on the quality of the data collected, which determines the overall outcome of the study. Aims to assess the factors affecting the inclusion of Russian physicians-researchers in CT, and to determine their role in relations with patients-participants. Materials and methods. The study was organized as a part of the Russian multicenter face-to-face study. A survey was conducted of researchers from 10 cities of Russia (20172018). The participation in the survey for doctors was anonymous and voluntary. Results. The study involved 78 respondents. Most research doctors highly value the importance of research for science (4,84 0,39), society (4,67 0,46) and slightly lower for participating patients (4,44 0,61). The expectations of medical researchers are related to improving their financial situation and attaining new experience (n = 14; 18,18%). However, the opportunity to work with new technologies of treatment and diagnosis (n = 41; 52,56%) acted as a motivating factor. According to the questionnaire, the vast majority of research doctors (n = 29; 37,18%) believe that the main reason for patients to participate in CT is to receive quality and free medical care. The most significant obstacle to the inclusion of participants in CT was the side effects of the study drug (n = 38; 48,71%). Conclusions. The potential of clinical researchers in Russia is very high. The patient-participant acts for the research doctor as the subject of the study, and not the object, so the well-being of the patient is not indifferent to the doctor. However, the features of the functioning of our health care system form the motivation of doctors-researchers (additional earnings, professional self-development) and the way they perceive the motivation of patients (CT as an opportunity to receive quality medical care).

scholarly journals A Numerical Study of the Effect of Particle Size on Particle Deposition on Turbine Vanes and Blades

2021 ◽  
Vol 13 (5) ◽  
pp. 168781402110178
Author(s):  
Zhengang Liu ◽  
Weinan Diao ◽  
Zhenxia Liu ◽  
Fei Zhang
Keyword(s):  
Particle Size ◽  
Particle Deposition ◽  
Numerical Study ◽  
Stokes Number ◽  
Capture Efficiency ◽  
Particle Capture ◽  
Factors Affecting ◽  
Pressure Surface ◽  
Deposition Area ◽  
Turbine Vanes

Particle deposition could decrease the aerodynamic performance and cooling efficiency of turbine vanes and blades. The particle motion in the flow and its temperature are two important factors affecting its deposition. The size of the particle influences both its motion and temperature. In this study, the motion of particles with the sizes from 1 to 20 μm in the first stage of a turbine are firstly numerically simulated with the steady method, then the particle deposition on the vanes and blades are numerically simulated with the unsteady method based on the critical viscosity model. It is discovered that the particle deposition on vanes mainly formed near the leading and trailing edge on the pressure surface, and the deposition area expands slowly to the whole pressure surface with the particle size increasing. For the particle deposition on blades, the deposition area moves from the entire pressure surface toward the tip with the particle size increasing due to the effect of rotation. For vanes, the particle capture efficiency increases with the particle size increasing since Stokes number and temperature of the particle both increase with its size. For blades, the particle capture efficiency increases firstly and then decreases with the particle size increasing.

scholarly journals Supply Potential and Annual Availability of Timber and Forest Biomass Resources for Energy Considering Inter-Prefectural Trade in Tohoku Region of Japan

2020 ◽  
Vol 3 (1) ◽  
pp. 40
Author(s):  
Yusuke Matsuoka ◽  
Hiroaki Shirasawa ◽  
Uichi Hayashi ◽  
Kazuhiro Aruga
Keyword(s):  
Tree Species ◽  
Forest Biomass ◽  
Wood Chip ◽  
Site Index ◽  
Geographical Survey Institute ◽  
Digital Elevation ◽  
Gis Data ◽  
Biomass Resource ◽  
Biomass Resources ◽  
Generation Capacity

To promote sustainable timber and forest biomass utilization, this study estimated technically feasible and economically viable availability considering forest regenerations. This study focuses on five prefectures, namely, Aomori, Iwate, Miyagi, Akita, and Yamagata, and considers the trade between these prefectures. The data used in this study include forest registration (tree species and site index) and GIS data (information on roads and subcompartment layers) from the prefectures for private and communal forests. Additionally, this study includes GIS data (subcompartment layers, including tree species) from the Forestry Agency of Japan for national forests as well as 10-m-grid digital elevation models (DEMs) from the Geographical Survey Institute. As a result, supply potentials of timber and forest biomass resources were estimated at 11,388,960 m3/year and 2,277,792 m3/year, respectively. Then, those availabilities were estimated at 1,631,624 m3/year and 326,325 m3/year. Therefore, the rate of availabilities to supply potentials was 14.3%. Since timber production, and wood chip usage from thinned woods and logging residues in 2018 were 4,667,000 m3/year and 889,600 m3/year, respectively, the rates of timber and forest biomass resource availabilities to those values were 35.0% and 36.7%, respectively. Furthermore, the demand was estimated at 951,740 m3/year from 100,000 m3/year with the generation capacity of 5 MW. The rate of forest biomass resource availability versus the demand was 34.2%. The rates were increased to 64.1% with an additional regeneration subsidy, 173.3% with the thinning subsidy, and 181.5% with both subsidies. Thus, the estimated availability with both subsidies met the demand sufficiently in this region.

scholarly journals Physicochemical factors affecting the wettability of copper mine blasting dust

2021 ◽  
Author(s):  
Longzhe Jin ◽  
Jianguo Liu ◽  
Jingzhong Guo ◽  
Jiaying Wang ◽  
Tianyang Wang
Keyword(s):  
Particle Size ◽  
Physicochemical Properties ◽  
Pore Structure ◽  
Total Pore Volume ◽  
Open Pit ◽  
X Rays ◽  
Factors Affecting ◽  
Copper Mine ◽  
Mineral Components ◽  
Hydrophobic Component

AbstractTo investigate the factors affecting the wettability of copper mine blasting dust, the primary blasting dust was collected from an open-pit copper mine and separated into hydrophilic blasting dust (HLBD) and hydrophobic blasting dust (HBBD) using water flotation method. The physicochemical properties of HLBD and HBBD were measured and compared with each other. The properties included particle size distributions (PSDs), micromorphologies, pore structures, mineral components and surface organic carbon functional groups. The results show that particle size and pore structure of the blasting dust are the main factors affecting its wettability. Specifically, particle size of HBBD is smaller than that of HLBD, and their respiratory dust (less than 10 µm) accounts for 61.74 vol% and 53.00 vol%, respectively. The pore structure of HBBD is more developed, and the total pore volume of HBBD is 1.66 times larger than that of HLBD. The identical mineral compositions were detected in HLBD and HBBD by X-rays diffraction (XRD); however, the surface organic hydrophobic component of HBBD is slightly larger than that of HLBD, this may be the reason for the poor wettability of HBBD. This study is significant to understand the effects of physicochemical properties of copper mine blasting dust on its wettability.

scholarly journals Teleworking and Online Shopping: Socio-Economic Factors Affecting Their Impact on Transport Demand

2021 ◽  
Vol 13 (13) ◽  
pp. 7211
Author(s):  
Juan Ramón López Soler ◽  
Panayotis Christidis ◽  
José Manuel Vassallo
Keyword(s):  
Urban Areas ◽  
Online Shopping ◽  
New Technologies ◽  
Age Groups ◽  
Mobility Patterns ◽  
Factors Affecting ◽  
Ex Post ◽  
Potential Impact ◽  
Commuting Patterns ◽  
Socio Economic Factors

Teleworking and online shopping became commonplace during the COVID-19 pandemic and can be expected to maintain a strong presence in the foreseeable future. They can lead to significant changes in mobility patterns and transport demand. It is still unclear, however, how extensive their adoption can be, since each individual has different preferences or constraints. The overall impact on transport depends on which segments of the population will modify their behaviour and on what the substitutes to the current patterns will be. The purpose of this work is to identify the user profiles and spatial aspects that affect the adoption of teleworking and online shopping, and to explore the potential impact on transport demand. To that end, data from an EU-wide survey on mobility were analysed using a Machine Learning methodology. The results suggest that while the take up of the new work and consumption patterns is high on average, there are significant differences among countries and across different socio-economic profiles. Teleworking appears to have a high potential mainly in certain services sectors, affecting commuting patterns predominantly in large urban areas. Online shopping activity is more uniform across the population, although differences among countries and age groups may still be relevant. The findings of this work can be useful for the analysis of policies to encourage the uptake of new technologies in transport and mobility. They can be also a good reference point for future studies on the ex-post analysis of the impacts of the pandemic on mobility.

scholarly journals Hydropower, Geothermal, and Ocean Energy

MRS Bulletin ◽  
2008 ◽  
Vol 33 (4) ◽  
pp. 389-395 ◽  
Author(s):  
Ralph E.H. Sims
Keyword(s):  
Renewable Energy ◽  
Large Scale ◽  
New Technologies ◽  
Materials Science ◽  
Development Stage ◽  
Design Development ◽  
Ocean Energy ◽  
Improve Design ◽  
And Performance ◽  
Improve Reliability

AbstractSome forms of renewable energy have long contributed to electricity generation, whereas others are just emerging. For example, large-scale hydropower is a mature technology generating about 16% of global electricity, and many smaller scale systems are also being installed worldwide. Future opportunities to improve the technology are limited but include upgrading of existing plants to gain greater performance efficiencies and reduced maintenance. Geothermal energy, widely used for power generation and direct heat applications, is also mature, but new technologies could improve plant designs, extend their lifetimes, and improve reliability. By contrast, ocean energy is an emerging renewable energy technology. Design, development, and testing of a myriad of devices remain mainly in the research and development stage, with many opportunities for materials science to improve design and performance, reduce costly maintenance procedures, and extend plant operating lifetimes under the harsh marine environment.

scholarly journals Spatiotemporal Changes and Obstacle Factors of Forest Ecological Security in China: A Provincial-Level Analysis

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1526
Author(s):  
Honghong Yu ◽  
Jiameng Yang ◽  
Mengyuan Qiu ◽  
Zhiyong (John) Liu
Keyword(s):  
Comprehensive Evaluation ◽  
Mainland China ◽  
Development Trend ◽  
Evaluation Index System ◽  
Utilization Efficiency ◽  
Ecological Security ◽  
Factors Affecting ◽  
Provincial Level ◽  
Resource Endowment ◽  
Pressure Indicators

Under the background of China’s proposal to achieve “carbon neutralization and carbon peak”, it is an important task for each province to clarify their forest ecological security (FES) status. However, there is little understanding of the temporal and spatial evolution of forest ecological security and its influencing factors. Based on the Pressure-State-Response (PSR) model, this paper constructed a comprehensive evaluation index system for forest ecological security and used the CRITIC method and panel data to estimate the dynamic changes in FES for 31 provinces in China (excluding Hong Kong, Macao, and Taiwan) between 2009 and 2018. Furthermore, the obstacle degree model was used to determine the important obstacle factors affecting FES. The results showed that: (1) The comprehensive indices of FES of most provinces in mainland China were increasing, showing a good development trend during the study period; (2) subject to the limitations of resources and economic conditions, the FES at the provincial level showed significant spatial heterogeneity, which generally presents a distribution characteristic of “low in the western region and high in the central and eastern regions”; and (3) the primary obstacles restricting the improvement of FES level in most provinces of China were forest state indicators or input response indicators, followed by pressure indicators. Therefore, it is recommended to take targeted measures to reduce the intensity of forest cutting and the incidence of forest disasters, improve the utilization efficiency of forest resources, the productivity of forestland and the input-output level of forestry industry, and strengthen the training of professional talents and technical input according to the resource endowment condition of each province so as to improve the level of forest ecological security.

scholarly journals Tailoring Adsorption Induced Switchability of a Pillared Layer MOF by Crystal Size Engineering

2020 ◽  
Author(s):  
Leila Abylgazina ◽  
Irena Senkovska ◽  
Sebastian Ehrling ◽  
Volodymyr Bon ◽  
Petko Petkov ◽  
...  
Keyword(s):  
Particle Size ◽  
Low Frequency ◽  
Polar Molecules ◽  
Adsorption Enthalpy ◽  
Factors Affecting ◽  
University Of Technology ◽  
Order Of Magnitude ◽  
Crystal Structural ◽  
Critical Particle Size ◽  
Characteristic Adsorption

The pillared layer framework DUT-8(Zn) (Zn<sub>2</sub>(2,6-ndc)<sub>2</sub>(dabco), 2,6-ndc = 2,6-naphthalenedicarboxylate, dabco = 1,4-diazabicyclo-[2.2.2]-octane, DUT = Dresden University of Technology) is a prototypical switchable MOF, showing characteristic adsorption and desorption induced open phase (<i>op</i>) to closed phase (<i>cp</i>) transformation associated with huge changes in cell volume. We demonstrate switchability strongly depends on a framework-specific critical particle size (d<i><sub>crit</sub></i>). The solvent removal process (pore desolvation stress contracting the framework) significantly controls the <i>cp</i>/<i>op</i> ratio after desolvation and, subsequently, the adsorption induced switchability characteristics of the system. After desolvation, the dense <i>cp</i> phase of DUT-8(Zn) shows no adsorption-induced reopening and therefore is non-porous for N<sub>2</sub> at 77 K and CO<sub>2</sub> at 195 K. However, polar molecules with a higher adsorption enthalpy, such as the polar molecules such as chloromethane at 249 K and dichloromethane (DCM) at 298 K can reopen the macro-sized crystals upon adsorption. For macro-sized particles, the outer surface energy is negligible and only the type of metal (Zn, Co, Ni) controls the DCM-induced gate opening pressure. The framework stiffness increases from Zn to Ni as confirmed by DFT calculations, X-ray crystal structural analyses, and low frequency Raman spectroscopy. The partial disintegration of the Zn based node hinges produces an overall increased stabilization of<i> cp </i>vs. <i>op</i> phase shifts the critical particle size at which switchability starts to become suppressed to even lower values (d<i><sub>crit</sub></i> < 200 nm) as compared to the Ni-based system (<i>d<sub>crit</sub></i> ≈ 500 nm). Hence, the three factors affecting switchability (energetics of the empty host, (<i>E<sub>op</sub>-E<sub>cp</sub></i>) (I), particle size (II), and desolvation stress (III)) appear to be of the same order of magnitude and should be considered collectively, not individually.

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