Pine weevils (Hylobius abietis L.) pose a significant threat to conifer seedlings by feeding on the bark, thus damaging or killing seedlings. Historically, insecticides were used to suppress such ...damage, but were slowly phased out in Sweden due to environmental and health concerns. This study aimed to assess field performance of an alternative protection method: mechanical coating applied to the stem of planted Norway spruce (Picea abies) seedlings. Field trials were conducted on 14 sites in south Sweden, using four different types of mechanical protection (Cambiguard, Conniflex, Ekovax, Hylonox), standard insecticide (Merit Forest), and ambient control. Seven sites were established in the drought year of 2018 and seven more in 2019. This allowed for additional investigation of the effect of drought on seedling establishment and possible interaction with pine weevil damage. Seedlings were surveyed for survival and height after the first, second and fourth growing season. Results show drought as the main source of damage for seedlings planted in 2018, with no significant effect of insecticide or mechanical protection on survival of seedlings. However, mechanical protections performed equally well as insecticide and positively increased survival by 30 %, compared to untreated, four growing seasons after planting for seedlings planted in 2019. Seedling height was not significantly affected by planting year or any of the treatments, suggesting no adverse effects of coating application. However, a synergistic effect between pine weevil damage and drought was observed, where even low levels of pine weevil damage resulted in high mortality for seedlings planted in 2018, compared to those planted in 2019. Additionally, for seedlings planted in 2019, damage to the top of the stem did not result in significant mortality, until high damage levels were reached (40 % and above). The opposite was found for seedlings planted in a 2018 drought year, where both damage to the top and the bottom of the stem followed a linear response. In conclusion, we show that investigated mechanical protection methods can be considered a viable replacement for insecticides, but our results also highlight the importance of considering multiple environmental stressors such as drought and pest damage on seedling establishment.
•Mechanical protection performed equally well as insecticide in a non-drought year.•There was no effect of mechanical protection on seedling growth.•Drought was the dominant damage factor to seedlings planted in a drought year.•Weevil damage to stem’s tops had a lower impact on survival in a non-drought year.•There was a synergistic effect of pine weevil damage and drought in a drought year.
A hybrid BTMS considering heat dissipation and mechanical protection for prismatic battery modules is constructed, which combines the modularized liquid-cooling plate (MLCP) and the phase change ...material (PCM)-negative Poisson's ratio structural laminboard. The effects of interior structure, flow direction, flow rate, and cooling strategy of the MLCP on the thermal performance of the battery module were investigated. It showed that the proposed MLCP was able to weaken the heating effect of coolant along the flow path by more than 50 % through modularized design. Furthermore, the alternating cooling strategy of sub-domains of MLCP was designed, which halved the energy consumption of liquid cooling systems. In comparison to the case without the laminboard, the maximum temperature and temperature difference of the case with it were reduced by 3.79 °C and 2.50 °C, respectively. Meanwhile, the maximum stress and total deformation of the battery cell were also decreased by 1.67 MPa and 78.1 μm with the protection of the laminboard at 1000 N. With the MLCP and the multifunctional laminboard, the maximum temperature and temperature difference of the battery module were kept below 35 °C and 4 °C, respectively, even at a high discharge current of 100 A and under dynamic conditions.
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•Thermal, mechanical, lightweight, and energy-saving designs are considered in BTMS.•Modularized liquid-cooling plate is designed to improve temperature inconsistency.•A novel laminboard is proposed combining negative Poisson's ratio structure and PCM.•Alternating and delaying cooling strategies can both save energy consumption of BTMS.
One of the most challenging problems of no-insulation (NI) REBCO pancake coils is mechanical and thermal protection. Particularly, pancake coils suffer high stress during a local-normal state ...transition (quench event). One solution is a magnetic dam, which is merely NI windings with a few turns. The effectiveness of magnetic dams by 4-mm-wide NI windings was demonstrated numerically in the previous study. The effectiveness would be different when the REBCO tapes with different widths are employed. Therefore, in this article, the electromagnetic behaviors of NI REBCO pancake coils with the magnetic dam of 12-mm-wide REBCO tape are investigated numerically. The charging and the normal-state transition are simulated. It is demonstrated that the 4-mm-wide magnetic dam works more effectively due to the less screening current in the 4-mm-wide magnetic dam than the 12-mm-wide magnetic dam in this case.
In Portugal, mechanical protection gloves (MPG) are of mandatory use and during their use sweat is released and, consequently, the humidity of the material increases leading to conditions favorable ...to the growth of microorganisms. However, no studies have been conducted in MPG to assess the bioburden. This study intended to determine the bioburden present in MPG and their biological effects, and to discuss the possibility to use MPG as a passive method to assess occupational exposure to microbial contamination. Fungal burden was characterized through molecular tools for fungal toxigenic species, and antifungal resistance and mycotoxins profiles were determined. Cell viability was determined in swine kidney (SK) monolayer and hepatocellular carcinoma (Hep G2) cell lines. All MPG samples presented Gram-negative bacteria. The fungal contamination ranged from 0 CFU.m−2 in both MEA and DG18, to 5.09 × 106 and 2.75 × 106 and the most commonly fungi found was Aspergillus spp. (50.46%). Azole resistant Aspergillus sections were found in azole supplemented media. Aspergillus sections (Circumdati, Flavi, Fumigati and Versicolores) were detected by molecular tools in 66 out of 67 samples. The most reported mycotoxin was mycophenolic acid (89.6%). HepG2 cells appear to be more sensitive to MPG contamination, with high cytotoxicity (IC50 < 0.05 mm2/ml) observed for 18 out of 57 gloves.
MPG can be used in passive sampling to assess occupational exposure to bioburden in waste sorting industries and contribute for risk characterization. Some contaminants of MPG had cytotoxic potential and affected the biology of hepatic cells more than renal cells.
•Gram-negative bacteria were found in all the Mechanic Protection Gloves (MPG).•Aspergillus sections with toxigenic and azole resistance potential were observed.•Mycotoxins exposure through ingestion route by hand-mouth contact is possible.•Cytotoxic potential affecting hepatic cells more than renal cells was observed.•MPG can be an adequate passive sampling method to estimate workers exposure.
Inspired by the structure of proteins, designed by nature to function as nanoscale shock absorbers, we propose the concept of harnessing structural instabilities to repeatedly filter out forces, e.g. ...from a vibrating environment, that exceed the permitted level. In the context of engineering applications, such remarkable mechanical protection has only been possible with complicated feedback-control; yet, we show that it can be materialized by means of architected materials that include force-sensitive building blocks, i.e. mechanical units that are carefully designed to undergo reversible morphological changes when forces exceed the permitted level. Experiments with 3D-printed prototypes and computer simulations demonstrate that forces transferred from a vibrating environment do not exceed the design threshold, irrespective of the amplitude or frequency of the vibrations. The design threshold is also maintained under impacts. With today’s manufacturing technology, the underlying principles can be implemented at all practical scales, from sub-millimeter size to meters, and the behavior can be tailored per application.
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Excessive pollen harvesting by bees can compromise the reproductive success of plants. Plants have therefore evolved different morphological structures and floral cues to narrow the spectrum of ...pollen feeding visitors. Among "filtering" mechanisms, the chemical and mechanical protection of pollen might shape bee-flower interactions and restrict pollen exploitation to a specific suite of visitors such as observed in Asteraceae. Asteraceae pollen is indeed only occasionally exploited by generalist bee species but plentifully foraged by specialist ones (i.e., Asteraceae paradox). During our bioassays, we observed that micro-colonies of generalist bumblebee (
L.) feeding on
pollen (Asteraceae) reduced their pollen collection and offspring production. Bees also experienced physiological effects of possible defenses in the form of digestive damage. Overall, our results suggest the existence of an effective chemical defense in Asteraceae pollen, while the hypothesis of a mechanical defense appeared more unlikely. Pre- and post-ingestive effects of such chemical defenses (i.e., nutrient deficit or presence of toxic compounds), as well as their role in the shaping of bee-flower interactions, are discussed. Our results strongly suggest that pollen chemical traits may act as drivers of plant selection by bees and partly explain why Asteraceae pollen is rare in generalist bee diets.
Aim
High foliar silicon (henceforth Si) concentration protects plant tissues against herbivory, but protection against several abiotic stressors has also been proposed, although the adaptive ...significance of these functions is still being debated. We aimed to explore the potential relationships between foliar Si content and chronic wind exposure across a large scale and multiple species and to analyse an overlooked alternative or complementary function of silicon in leaves: mechanical protection against wind.
Location
Mainland China.
Time period
From July to September during 2012–2014.
Major taxa studied
Two hundred and eighty‐two vascular plant species in predominantly herbaceous communities.
Methods
We compiled a dataset for leaf silicon concentration (Si) across 27 sites and 153 herbaceous plots within the major climate zones of China. We hypothesized that evolutionary lineages that generally have high Si should show positive relationships between leaf Si and mean annual wind speed.
Results
Within major families with generally high Si (especially grasses, sedges and composites), leaf Si exhibits a consistently positive correlation with mean wind speed among species across China. For the seven widespread monocot species with high leaf Si, including the globally distributed common reed (Phragmites australis), intraspecific variation in leaf Si exhibits the same consistent positive correlation with mean wind speed.
Main conclusions
Our findings suggest that high leaf Si is likely to have widespread adaptive value for wind exposure of leaves, at least in several very widespread families and species of herbaceous plants. Damage from wind is a danger for plants in many ecosystems, hence these findings are of global significance and indicate that further research into large‐scale variation of leaf Si and mechanical traits in relationship to wind exposure is likely to be illuminating.
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Emiliania huxleyi has evolved an extremely intricate coccosphere architecture. The coccosphere is comprised of interlocking coccoliths embedded in a polysaccharide matrix. In this ...work, we performed in-situ scanning electron microscopy based compression tests and conclude that coccospheres have a mechanical protection function. The coccosphere exhibits exceptional damage tolerance in terms of inelastic deformation, recovery and stable crack growth before catastrophic fracture, a feature, which is not found in monolithic ceramic structures. Some of the mechanical features of the coccospheres are due to their architecture, especially polysaccharide matrix that acts as a kind of bio-adhesive. Our data provide strong evidence for the mechanical protection-hypothesis of coccolithophore calcification, without excluding other functions of calcification such as various biochemical roles discussed in the literature.
Although bio-mechanics of shell structures like nacre have been studied over the past decade, coccospheres present an architecture that is quite distinct and complex. It is a porous cell structure evolved to protect the living algae cell inside it in the oceans, subjected to significant hydrostatic pressure. Despite being made of extremely brittle constituents like calcium carbonate, our study finds that coccospheres possess significant damage tolerance especially due to their interlocking coccolith architecture. This will have consequences in bio-mimetic design, especially relating to high pressure applications.
In Peru, the pineapple (Ananas comosus var. comosus) has 14 000 cultivated hectares, with an average yield of 22 t/ha. Commercial cultivars in order of importance are ...’Samba’,’Hawaiana’,’Pucalpina’,’Roja Trujillana’,’Cayena Lisa’ and ‘Golden’ (MD-2) which are cultivated in different regions of the country, but the largest areas are in the central jungle. The pineapple has several phytosanitary problems, but the most important is the “fruit spot” caused by Penicillium funiculosum and Fusarium moniliforme. There are three types of spots: “dry black spot”, “wet black spot” and “spot with galleries”, the latter being the most important
and associated with the “pineapple fly” (Melanoloma viatrix). This paper presents a review of the biology of the “pineapple fly”, a description of the “spot with galleries” and the experiences developed for its control in the country
En el Perú la piña (Ananas comosus var. comosus) tiene 14 000 ha cultivadas, con un rendimiento promedio de 22 t/ha. Los cultivares comerciales en orden de importancia son ‘Samba’, ‘Hawaiana’, ‘Pucalpina’, ‘Roja Trujillana’, ‘Cayena Lisa’ y ‘Golden’ (MD-2), que se siembran en las diferentes regiones del país, pero las mayores áreas se encuentran en la zona conocida como la selva central. La piña tiene diversos problemas fitosanitarios, pero el principal es la llamada “mancha del fruto” causada por Penicillium funiculosum y Fusarium moniliforme. Existen tres tipos de mancha: “mancha negra seca”, “mancha negra húmeda” y mancha con galerías”. Esta última es la más importante y está asociada a la “mosca de la fruta de la piña” (Melanoloma viatrix). En este trabajo se presenta una revisión sobre la biología de la “mosca de la fruta de la piña”, se describe la “mancha con galerías” y se exponen las experiencias desarrolladas para su control en el país.
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