scholarly journals Seedlings of alpine species do not have better frost-tolerance than their lowland counterparts

Alpine Botany ◽  
2020 ◽  
Vol 130 (2) ◽  
pp. 179-185 ◽  
Author(s):  
Sergey Rosbakh ◽  
Vera Margreiter ◽  
Bernardica Jelcic
Keyword(s):  
Seedling Survival ◽  
Frost Tolerance ◽  
High Elevation ◽  
Alpine Plants ◽  
Species Pairs ◽  
Alpine Species ◽  
Alpine Habitats ◽  
Main Factors ◽  
Effects Of Drought ◽  
Set Up

Abstract In contrast to adult plants, little is known about the frost-tolerance of seedlings of alpine species, despite the fact that frost has been considered as one of the main factors limiting plant recruitment in high elevation. Here we report the results of a comparative study on seedling frost-tolerance of nine congeneric species pairs with lowland (0–900 m a.s.l.) and alpine (1800–2700 m a.s.l.) distribution. Similarly to adult alpine plants, we expected seedlings of alpine species to be more frost-tolerant than their lowland counterparts. Frost-tolerance was estimated under laboratory conditions by exposing seedlings to frost events from − 1 to − 9 °C, calculated as the temperature at which 50% of the seedlings were lethally damaged by frost (LT50). The LT50 values varied between − 1.95 and − 6.11 °C suggesting that seedling of all tested species could potentially survive mild and/or short frosts, but might be lethally damaged by severe and/or continuous frost events. The LT50 values for lowland and alpine species did not differ statistically and were on average − 3.96 ± 0.18 °C and − 4.16 ± 0.43 °C, respectively. These findings did not confirm our hypothesis that seedlings of alpine species have higher frost-tolerance than seedlings of lowland species. Four possible reasons could explain this pattern. They include (1) comparable levels of negative-stress in both lowland and alpine habitats, (2) opportunistic seed germination strategy in alpine plants, (3) peculiarities of our experimental set up and (4) potentially stronger effects of drought on alpine seedling survival than frost.

scholarly journals Past and future snowmelt trends in the Swiss Alps: the role of temperature and snowpack

2021 ◽  
Vol 165 (3-4) ◽  
Author(s):  
Maria Vorkauf ◽  
Christoph Marty ◽  
Ansgar Kahmen ◽  
Erika Hiltbrunner
Keyword(s):  
Snow Depth ◽  
Growing Season ◽  
High Elevation ◽  
Alpine Plants ◽  
Swiss Alps ◽  
Climate Change Scenarios ◽  
Freezing Damage ◽  
Strong Shift ◽  
Air Temperatures ◽  
Early Snowmelt

AbstractThe start of the growing season for alpine plants is primarily determined by the date of snowmelt. We analysed time series of snow depth at 23 manually operated and 15 automatic (IMIS) stations between 1055 and 2555 m asl in the Swiss Central Alps. Between 1958 and 2019, snowmelt dates occurred 2.8 ± 1.3 days earlier in the year per decade, with a strong shift towards earlier snowmelt dates during the late 1980s and early 1990s, but non-significant trends thereafter. Snowmelt dates at high-elevation automatic stations strongly correlated with snowmelt dates at lower-elevation manual stations. At all elevations, snowmelt dates strongly depended on spring air temperatures. More specifically, 44% of the variance in snowmelt dates was explained by the first day when a three-week running mean of daily air temperatures passed a 5 °C threshold. The mean winter snow depth accounted for 30% of the variance. We adopted the effects of air temperature and snowpack height to Swiss climate change scenarios to explore likely snowmelt trends throughout the twenty-first century. Under a high-emission scenario (RCP8.5), we simulated snowmelt dates to advance by 6 days per decade by the end of the century. By then, snowmelt dates could occur one month earlier than during the reference periods (1990–2019 and 2000–2019). Such early snowmelt may extend the alpine growing season by one third of its current duration while exposing alpine plants to shorter daylengths and adding a higher risk of freezing damage.

The Influencing Factors and Assessment Rule of Fatigue Life of Shaft Based on Product Lifecycle Management

2007 ◽  
Vol 561-565 ◽  
pp. 2253-2256 ◽  
Author(s):  
You Tang Li ◽  
Ping Ma ◽  
Jun Tian Zhao
Keyword(s):  
Fatigue Life ◽  
Influencing Factors ◽  
Axial Stress ◽  
Assessment Method ◽  
Product Lifecycle Management ◽  
Product Lifecycle ◽  
Fatigue Design ◽  
Main Factors ◽  
Set Up ◽  
Lifecycle Management

Product lifecycle management is one of the main developmental aspects of advanced manufacturing technology. Anti-fatigue design is the key content in product lifecycle management. For designing the fatigue life of shaft exactly and determining the assessment method, the influencing factors must be realized roundly. The mechanical model of shaft is set up at first, and then the main factors that affect the fatigue life of shaft is discussed, the interrelations of the main factors and the framework are founded. The assessment equation of fatigue life for shaft is put forward and the influencing coefficient of multi-axial stress to fatigue life is analyzed. The results of this paper will establish the base of anti-fatigue and assessment life of shaft.

Application of Case Based Reasoning in Technology Industry Competency Development

2013 ◽  
Vol 433-435 ◽  
pp. 2351-2358
Author(s):  
Hui Ling Hsu ◽  
Li Chung Chao
Keyword(s):  
Case Based Reasoning ◽  
Competency Development ◽  
Knowledge Database ◽  
Technology Industry ◽  
Automation Equipment ◽  
Main Factors ◽  
Set Up ◽  
Training Path ◽  
Productive Output ◽  
Case Based

This study aims to assist the semiconductor assembly and testing industry in finding the best way of talent training. Firstly, the analysis of competency designs the training path according to engineers' different realms, introduces Case-Based Reasoning (CBR) combined with courses of the analysis of competency. Then, after the interview of professional engineers regarding their experiences, we analyze the courses' main factors, the degree of demand of instituting the courses, and finally set up the knowledge database of talent training. The results will inspire the training path for automation equipment and process and act as reference for the human resources department, reducing discrepancies between the tech and management department for required skills to equipment and manufacturing processing and enhancing the productive output.

scholarly journals Use of summer habitat by caribou on the north slope of a mountain near the Macmillan Pass, N.W.T.

Rangifer ◽  
1996 ◽  
Vol 16 (4) ◽  
pp. 311 ◽  
Author(s):  
James F. Quayle ◽  
G. Peter Kershaw
Keyword(s):  
Habitat Type ◽  
Indirect Evidence ◽  
High Elevation ◽  
North Slope ◽  
Habitat Types ◽  
The North ◽  
Feeding Cycle ◽  
Alpine Habitats ◽  
Pellet Density ◽  
Insect Harassment

Habitat use by woodland caribou was investigated by counting pellet-groups, sampling phytomass, and evaluating topography in nine habitat-types on the north slope of an unnamed mountain near Macmillan Pass, N.W.T. Caribou pellets were most abundant in high elevation habitat-types, and pellet density was greatest in an alpine Lichen-Grass habitat-type with a slope of <1°. The high density of pellets in alpine areas may have resulted from of the use of cool, windy, alpine habitats by caribou seeking relief from insect harassment. There were no apparent relationships between pellet abundance, and phytomass of mosses, lichens, or graminoids, possibly as a result of caribou feeding and defecating in different habitats. The occurrence of pellets with a coalesced morphology in the barren Lichen-Grass habitat-type provided indirect evidence in support of a feeding cycle, whereby caribou visit lush habitats to feed, and return to open, alpine habitats to rest and ruminate.

scholarly journals A Coupled Model for Solution Flow and Bioleaching Reaction Based on the Evolution of Heap Pore Structure

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Shenghua Yin ◽  
Xun Chen ◽  
Chi Ma ◽  
Leiming Wang ◽  
Aixiang Wu
Keyword(s):  
Coupled Model ◽  
Small Particles ◽  
Copper Ore ◽  
Solution Flow ◽  
Pore Evolution ◽  
Main Factors ◽  
Set Up ◽  
Seepage Law ◽  
Leaching Reaction ◽  
The Relationship

Based on the basic seepage law, equations have been derived to descript the solution flow within the copper ore heap which is treated as anisotropy porous media. The relationship between heap permeability and pore ratio has been revealed. Given the consideration of cover pressure and particle dissolution, pore evolution model has been set up. The pore evolution mechanism, due to the process of dissolution, precipitation, blockage, collapse, and caking, has been investigated. The comprehensive model for pore evolution and solution flow under the effect of solute transport and leaching reaction has been established. A trapezoidal heap was calculated, and the estimated results show that permeability decreases with the decreasing of pore ratio. Therefore, the permeability of the heap with small particles is relatively low because of its low pore ratio. Furthermore, permeability and height are found to be the two main factors influencing the solution flow.

scholarly journals Trends in Population Size of Rare Plant Species in the Alpine Habitats of the Ukrainian Carpathians under Climate Change

Diversity ◽  
2018 ◽  
Vol 10 (3) ◽  
pp. 62 ◽  
Author(s):  
Yuriy Kobiv
Keyword(s):  
Climate Change ◽  
Plant Species ◽  
Frost Damage ◽  
High Mountain ◽  
Direct Impact ◽  
Alpine Plant ◽  
Cold Adapted ◽  
Subalpine Zone ◽  
Alpine Species ◽  
Alpine Habitats

Population trends in rare alpine plant species in the high-mountain zone of the Ukrainian Carpathians are described with regard to the types of habitats where they occur. Populations of cold-adapted species confined to snowbeds, alpine screes, poorly vegetated rocks, and the highest ridges, as well as mires and springs, are very vulnerable to climate change, while their habitats tend to shrink. The direct impact of warming affects mainly the most cryophilic species. Another driver of changes is climate-induced succession that results in denser vegetation cover and encroachment of more thermophilic plants, which replace low-competitive rare alpine species. Their replacement is largely caused by the loss of open microsites suitable for seed recruitment. However, the climate-driven decrease of snow cover often leads to frost damage to vegetation that provides gaps appropriate for the establishment of many rare species. One of the groups of species that benefit from warming includes rather thermophilic tall herbs that are more common in the subalpine zone but have been actively spreading at higher altitudes lately.

Microwave-Induced Catalytic Removal of Hazardous Gases

2015 ◽  
Vol 1092-1093 ◽  
pp. 882-885
Author(s):  
Huan Zhou ◽  
Zhen Xing Cheng ◽  
Nan Wang ◽  
Hong Peng Zhang ◽  
Hua Min Tang
Keyword(s):  
Removal Efficiency ◽  
Flow Rate ◽  
Microwave Field ◽  
Factors Affecting ◽  
Catalyst Type ◽  
Hazardous Gases ◽  
Main Factors ◽  
Set Up ◽  
Catalytic Removal ◽  
Hazardous Gas

A microwave-induced catalytic removal device was designed and set up for studying removal of hazardous or toxic gas from contaminated air. Catalytic oxidative Removal ratios of several hazardous gases of VOCs, CO and H2under microwave field were tested. Results suggested that structure of hazardous gas and catalyst type were main factors affecting the removal efficiency of hazardous gas. Oxidative catalyst contributed to removal of reductive gas. In addition, the flow rate also affected the removal efficiency.

A discussion on the origin and treatment of noise in industrial environments - Noise of gears

1968 ◽  
Vol 263 (1142) ◽  
pp. 369-380 ◽  
Keyword(s):  
Fatigue Life ◽  
Load Capacity ◽  
Operating Conditions ◽  
Gear Noise ◽  
Know How ◽  
Noise Radiation ◽  
The Past ◽  
Main Factors ◽  
Set Up ◽  
Acceptance Tests

In the past there were mainly two important factors in determining the performance of gear units: load capacity and fatigue life. In recent years, however, the noise radiation of running gears is of growing importance. It is now becoming impossible to design gears without considering the significance of this new factor. While there are many data available in the literature for calculating the permissible load, speed, and fatigue life, no methods have so far been developed for a true prediction of the radiated gear noise. A definite noise level, however, is often subject to guarantee between manufacturer and customer. To meet these requirements two fundamental factors must be resolved. First, both partners must set up the conditions for acceptance tests, and secondly, the gear manufacturer must have the know-how to meet these particular requirements. Investigations were therefore, made to find out the main factors influencing gear noise in order to be able to reduce it. In addition eighty installed gear-units were tested to set up classifications regarding generated noise and operating conditions.

Fuzzy Comprehensive Assessment of Air Material Suppliers

2014 ◽  
Vol 596 ◽  
pp. 164-168
Author(s):  
Zhong Lv
Keyword(s):  
Comprehensive Assessment ◽  
Assessment Model ◽  
Science Assessment ◽  
Effective Measure ◽  
Assessment Index ◽  
Comprehensive Theory ◽  
Assessment Index System ◽  
Main Factors ◽  
Set Up ◽  
Hierarchy Process

Science assessment to air material suppliers is an effective measure that insures cost controlling and safety operating of an airline. Through analyzing the main factors of the air material suppliers, this paper constructs an assessment index system of the air material suppliers. The weights of assessment indexes is determined by means of the analytical hierarchy process (AHP). A assessment model of air material suppliers based on fuzzy comprehensive theory has also been set up. The model is validated through example. This prove that the method can give an overall comprehensive assessment level of the air material suppliers.

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