Artificially Damaged Research Articles

Plant–plant communication in Camellia japonica and C. rusticana via volatiles

Plants emit volatile compounds when they are subjected to herbivorous, pathogenic, or artificial damages. Both the damaged plant and the neighboring intact plants induce resistance when they receive these volatiles, a phenomenon known as plant–plant communication. However, field observations of this phenomenon are limited. To understand the nature of plant–plant communication, we collected information about intra- and inter-plant signaling via volatiles in Camellia japonica and C. rusticana under natural conditions. We exposed intact branches of damaged plant (intra-plant) or neighboring plant (inter-plant) to artificially damaged plant volatiles (ADPVs). Leaf damage reduced in ADPVs-exposed branches in the neighboring plants compared to branches that were exposed to volatiles from intact leaves, thus, indicating that inter-plant signaling occur by the emission of volatiles from damaged leaves. We also conducted an air-transfer experiment wherein the headspace air of the damaged branch was transferred to the headspace of intact branches. Leaf damage reduced on the ADPVs-transferred branch compared to the control branch. The effect of volatiles on damage reduction lasted for three months. Our results indicate that ADPVs in Camellia species contain cues that induce resistance in neighboring plants. Our findings improve understanding of plant defense strategies that may be used in horticulture and agriculture.

The effects of florivory on floral attractiveness and fruit production in Daustinia montana (Convolvulaceae)

• Florivory affects floral attractiveness in Daustinia montana . • Pollinator visits decrease when corolla damage increases in Daustinia montana . • Fruit production under natural conditions was greater among intact flowers. Floral attractiveness is a strong determinant of pollination success, although the same attributes that attract pollinators can also attract florivores. Consumption of the corolla and/or reproductive structures can reduce pollinator visitation frequencies and depress fruit and/or seed set. We hypothesized that florivory would negatively affect the visitation frequencies of floral visitors and natural fruit set in Daustinia montana , a herbaceous species endemic to Brazil. We collected inflorescences of D. montana and recorded the numbers of floral structures with signs of florivory, as well as the locations of that damage, to quantify natural florivory. Artificial damage experiments were carried out with the corollas and stamens to experimentally determine the influence of florivory on the frequency of floral visits. We also randomly marked intact flowers and those naturally damaged by florivory and measured fruit set. More intact floral buds were observed under natural conditions than buds damaged by florivory. We observed that all of the analyzed structures (stamens/pistil and corolla) are generally attacked simultaneously, as opposed to only one specific structure. Intact flowers (controls) demonstrated greater rates of pollinator visitation than experimentally damaged flowers. The visitation frequencies of nectar thieves were not different between intact flowers and artificially damaged flowers. Fruit set under natural conditions was greater for intact flowers than for those that had experienced natural florivory. Our data indicated that floral damage had negative effects on floral attractiveness to pollinators. The greater natural production of fruits from intact flowers is indicative of the degree to which florivory can impact plant reproduction.

Experimental and numerical investigations on corroded stainless-clad bimetallic steel bar with artificial damage

Artificial damage was introduced in stainless-steel cladding layer (SSCL) of stainless-clad bimetallic steel bars (SCBSBs) to simulate the initial imperfection. The corrosion performances and mechanical properties of SCBSBs were investigated experimentally. Based on the test results of corrosion performance of artificially damaged SCBSBs, corrosion mainly occurred in the damaged area. The wc developed faster than the dc, with increases in corrosion ratio. The increment in corrosion ratio led to decreases in fy, fu, εu and δ. Predictive equations were proposed to quantify influences of corrosion on fy, fu, εy, εu, εu/εy and δ. A stress-strain model was proposed to clarify mechanical properties of artificially damaged SCBSB specimens with various corrosion ratios. The comparisons among different steel bars were conducted to investigate differences in effects of corrosion on mechanical properties. Different energy indexes were calculated to quantify the ductility of artificially damaged SCBSB specimens comprehensively. The finite element analysis was carried out to investigate the effects of corrosion morphology and location on strength properties of SCBSBs. Based on numerical results, when corrosion ratio was the same, the fu and fy of corroded SCBSBs increased, with the increase in W/D. The effect of corrosion location on strength properties of corroded SCBSBs could be ignored. Contributions of this study were useful to determine resistance of structures with SCBSBs during the service life accurately.

Experimental Methods of One-floor Steel Constructions’ Seismic Stability – Analysis of Results

The article discusses several particularly significant questions related to seismic stability of steel frames. The tests produce the result of steel frame endurance under different loads, implying the condition of structure’s weakening. The paper presents the study of natural seismic noise indices fluctuations, displacement amplitude, noise decrease under various designs and implication of the dynamic loads. The issue of the impact made on the dynamic characteristic of changes are represented in the article’s sections, as well as the review of possible experimental methods of determining the endurance of the frames under seismic loads. The paper represents the empirical study of artificially damaged steel frames performance under the dynamic load, calculation of the extent of steel frame joints displacement, the degree of changes under natural and artificial seismic noise with load implication. The work aims at objective conclusion of frame performance, and states that loads and artificial damages modeling produces ineffective results for estimating the performance of frames in real/natural conditions, due to the fact that the effect made by frame’s connection nodes and the base was not taken into consideration. The paper implies further research in the area, with regard to the joint functioning of the foundation base and the frame under the dynamic load.

Virtual Geometric Reconstruction of Australopithecine Femora: A Methodological Evaluation

The fragmentary nature of fossils, and the need to extract as much information from them as possible, mandates that broken portions be reconstructed. Virtual reconstruction using geometric morphometric techniques based on the thin plate spline (TPS) function can be used to locate landmarks that represent missing portions of fossil specimens. Here we evaluate the accuracy of TPS‐based reconstruction in artificially damaged australopithecine distal femora.Surface models of modern human (n=35) and chimpanzee (n=37) distal femora, as well as those of two australopiths (casts of A.L. 129‐1a and A.L. 333‐4), were created using a structured light scanner. Articular surfaces were trimmed from the rest of the surface model. 1007 sliding semilandmarks were distributed across the articular surface, and semilandmarks were then slid to minimize the bending energy of the TPS function relative to an updated Procrustes average. Fossils were then virtually destroyed by removing semilandmarks to mimic the type of destruction observed in other fossil specimens. Removed portions increased from a small, central hole in the middle of each condyle to removal of the entire condyle. Average chimpanzee and human femora were used as references to create two separate reconstructions using geometric reconstruction based on the TPS function. Procrustes distances (PD) between each reconstruction and the original fossil were calculated to evaluate reconstruction accuracy.Reconstructions based on both human and chimpanzee averages deviated further from the original fossils as the level of artificial damage increased. When the entire medial condyle was reconstructed, the original morphology of both australopithecine fossils was intermediate between the human‐based and chimpanzee‐based reconstructions. For these reconstructions, Procrustes distances indicate that both A.L. 129‐1a and A.L. 333‐4 are most similar to the human‐based reconstruction (A.L. 129‐1a: PD = 0.001 vs. 0.002; A.L. 333‐4: PD = 0.002 vs. 0.003). When the entire lateral condyle was reconstructed, the fossils fell outside the possible morphologies bounded by the human‐based and chimpanzee‐based reconstructions. Procrustes distances indicate that both fossils are more similar to the human‐based reconstructions than those based on the average chimpanzee (A.L. 129‐1a: PD = 0.004 vs. 0.005; A.L. 333‐4: PD = 0.005 vs. 0.009). These results suggest that while the australopithecine medial femoral condyle may be considered an interpolation between chimpanzee and human morphology, the lateral condyle does not follow the same trend. For australopithecine distal femur reconstructions to be accurate, medial and lateral condyles should be considered separately.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Volatiles released by damaged leaves of Piper mollicomum (Piperaceae) act as cues for predaceous wasps: evidence using plasticine dummies as herbivore model

Volatiles released by damaged plants are used as cues by predators and parasitoids to find their herbivorous prey. Here, we assessed whether odor cues released by simulated herbivore-damaged leaves in Piper mollicomum attract predaceous wasps. We applied plasticine dummy caterpillars as an herbivore model to evaluate predation risk on undamaged and artificially damaged leaves by the mandible marks left by foraging wasps. Despite observing a tendency of a visual component in the wasp attraction (more marks on dummies under old naturally damaged leaves), we observed that chemical cues play a crucial role, with recent artificial damage and leaves baited with volatile essential oils of P. mollicomum attracting more wasps for the dummies than those untreated. Headspace analysis by GC–MS showed that undamaged leaves released small amounts of compounds, while damaged ones released 63 times more volatiles, which consisted of a blend containing mostly mono- and sesquiterpenoids. Histochemical tests revealed that terpenoids are located in oil cells spread among the leaf tissue, and may be released by the disruption of such cells when herbivores are feeding on leaves. We suggest that signals of disrupted plants differ from the mosaic of odor blends emitted by the background environment and may provide a detectable, although not necessarily specific, cue for prey presence. Such detectable cues are important for generalist foraging predaceous wasps, since they spend time searching for prey in different host plants.

Residual clamping force of bolt connections caused by sectional damage of nuts

To consider sectional damage of bolt connections by corrosion damage for the maintenance of steel structures, the residual clamping force of bolt connections was quantitatively examined depending on sectional damage of the nut sections developed from artificial cutting in this study. Thus, friction connection specimens using high-strength bolt connections were fabricated, and the nut sections in the bolt connections were artificially damaged using handheld cutting tools. To measure the change in the clamping force of the bolt connections, the change in strain measured in the bolt using a strain gage was examined after clamping and inducing artificial sectional damage to the nut. The bolt size and the shape and extent of sectional damage were the parameters considered in this study. The weight of the nut was measured after inducing artificial sectional damage to nut to calculate induced sectional damage of nut. From tests results for bolt connection with artificial sectional damaged nuts. The residual clamping forces of the bolt connections were decreased because of the reduced tensile resistance of the bolt connections, affected by the sectional damage of the nut. In case of high sectional damage in the nut section, a relatively higher change in the clamping force was found in the tested series of nuts. From regression analysis of the residual clamping force of the bolt connections, the estimation equations for the change in the residual clamping force developed from sectional damage of the nut were formulated using the damaged volume of the nut and diameter of the remaining nut section for the maintenance of bolt connections in steel structures.

Species-Specific Effects of Herbivory on the Oviposition Behavior of the Moth Manduca sexta

In Southwestern USA, the jimsonweed Datura wrightii and the nocturnal sphinx moth Manduca sexta form a pollinator-plant and herbivore-plant association. While certain plant volatile organic compounds (VOCs) attract moths for oviposition, it is likely that other host-derived olfactory cues, such as herbivore-induced VOCs, repel moths for oviposition. Here, we studied the oviposition preference of female M. sexta towards intact and damaged host plants of three species: D. wrightii, D. discolor (a less preferred feeding resource but also used by females for oviposition), and Solanum lycopersicum-tomato-(used by moths as an oviposition resource only). Damage was inflicted to the plants either by larval feeding or artificial damage. Mated females were exposed to an intact plant and a damaged plant and allowed to lay eggs for 10min. Oviposition preferences of females were highly heterogeneous in all cases, but a larger proportion of moths laid significantly fewer eggs on feeding-damaged and artificially damaged plants of S. lycopersicum. Many females also avoided feeding-damaged D. discolor and D. wrightii plants induced by treatment with methyl jasmonate. Chemical analyses showed a significant increase in the total amount of VOCs released by vegetative tissues of feeding-damaged plants, as well as species-specific increases in emission of certain VOCs. In particular, feeding-damaged S. lycopersicum plants emitted (-)-linalool, an odorant that repels moths for oviposition. Finally, the emission of D. wrightii floral VOCs, which are important in mediating feeding by adult moths (and hence pollination), did not change in plants damaged by larval feeding. We propose that the observed differential effects of herbivory on oviposition choice are due to different characteristics (i.e., mutually beneficial or parasitic) of the insect-plant interaction.

Real-time analysis of sulfur-containing volatiles in Brassica plants infested with root-feeding Delia radicum larvae using proton-transfer reaction mass spectrometry

Plants damaged by herbivores emit a variety of volatile organic compounds (VOCs). Here we used proton-transfer reaction mass spectrometry (PTR-MS) as a sensitive detection method for online analysis of herbivore-induced VOCs. Previously, it was found that Brassica nigra plants emit several sulfur-containing VOCs when attacked by cabbage root fly (Delia radicum) larvae with m/z 60 as a marker for the formation of allylisothiocyanate from the glucosinolate sinigrin. We tested the hypothesis that m/z 60 emission occurs only in plants with sinigrin in their roots. Additionally, we tested the hypothesis that methanethiol, dimethylsulfide and dimethyldisulfide are only emitted after larval infestation. Proton-transfer reaction mass spectrometry was used to track sulfur-containing VOCs from six different species of Brassica over time. The roots were either artificially damaged or infested with cabbage root fly larvae. Glucosinolate profiles of the roots were analysed using high-pressure liquid chromatography and compared with VOC emissions. Brassica nigra, B. juncea and B. napus primarily emitted m/z 60 directly after artificial damage or root fly infestation. Sulfide and methanethiol emissions from B. nigra and B. juncea also increased after larval damage but much later (6-12 h after damage). Brassica rapa, B. oleracea and B. carinata principally emitted methanethiol after artificial and after larval damage. Brassica oleracea and B. carinata showed some increase in m/z 60 emission after larval damage. Comparison with root glucosinolate profiles revealed that sinigrin cannot be the only precursor for m/z 60. The principal compound emitted after root damage is determined by the plant species, and not by damage type or root glucosinolate composition. Once determined, the principal compounds may be used as markers for identifying damaged or infested plants. Further analyses of plant enzymes involved in the breakdown of sulfur compounds is needed to reveal the origin of sulfur-containing VOCs from plants.

Florivory affects pollinator visitation and female fitness in Nemophila menziesii

While herbivory has traditionally been studied as damage to leaves, florivory - herbivory to flowers prior to seed set - can also have large effects on plant fitness. Florivory can decrease fitness directly, either through the destruction of gametes or through alterations to plant physiology during fruit set, and can also change the appearance of a flower, deterring pollinators and reducing seed set. In order to distinguish between these hypotheses, it is necessary to both damage flowers and add pollen in excess to study the effects of damage on pollen limitation. Very few studies have used this technique over the lifetime of a plant. Here I describe a series of experiments showing the effects of natural and artificial damage on reproductive success in the annual plant Nemophila menziesii (Hydrophyllaceae, sensu lato). I show that natural and artificial petal damage decreased radial symmetry relative to controls and that both types of damage deterred pollinator activity. Both naturally damaged flowers and artificially damaged flowers in the field set fewer fruit or seed relative to undamaged control flowers. Finally, in an experiment crossing artificial petal damage with pollen addition, petal damage alone over the lifetime of this plant decreased female fitness, but only after a threshold of damage was reached. The fitness effect appeared to be direct because there was no detectable effect of pollen addition on the relationship between florivory and fitness. This result implies that both damaged and undamaged plants show similar amounts of pollen limitation and suggests that pollinator-mediated effects contributed little to the negative effects of florivory on female fitness. Florivores may thus be an under-appreciated agent of selection in certain plants, although more experimental manipulation of florivory is needed to determine if it is important over a range of taxa.

Rapid changes of induced volatile organic compounds in Pinus massoniana

Using the thermal-desorption cold trap gas chromatography/mass spectrometer (TCT-GC-MS) technique, the composition and relative contents of volatile compounds were analyzed in undamaged (control), insect-damaged (ID) and artificially-damaged (AD) leaves of Pinus massoniana in field at different times and levels of damage. Results showed that although volatile substances were highly released earlier in AD leaves plants, they were significantly less abundant in AD than in ID leaves treatments. Also, the damage level considerably influenced the changes of induced volatile products from leaves. Compared with the control, the emission rate of camphene, β-pinene, phellandrene, caryophyllene and (E)-farnesene was high after 1 h in 25%–40% ID-affected leaves, whereas that of tricyclene, myrcene, camphene, β-Pinene, phellandrene and caryophyllene reached its maximum after 24 h in 60%–75% ID-affected leaves. In the same manner, some volatile compounds in the AD leaves treatment displayed their peaks just after 1 h, but others after 24 h. The AD and ID leaves at the damage level of 25%–40% did not exhibit an obvious regularity with time; however, in 60%–75% AD leaves, peaks of volatile substances were attained after 1 or 2 h. Our results also showed that the relative content of β-pinene increased and was higher in damaged than control plants. β-pinene plays an important role in inducing the insect resistance of P. massoniana trees.

Scopolamine in Brugmansia Suaveolens (Solanaceae): Defense, Allocation, Costs, and Induced Response

Brugmansia suaveolens (Solanaceae) contains tropane alkaloids (TAs), which can act as chemical defenses. Selective pressures might modulate the allocation of alkaloids within the plant, as postulated by optimal-defense theory. By tracing scopolamine, the most abundant TA in this species, we found that scopolamine in an artificial diet, in concentrations similar to those in leaves of B. suaveolens, increased mortality and prolonged developmental time of the larvae of the generalist noctuid moth Spodoptera frugiperda. A diet of undamaged leaves of B. suaveolens also showed a large negative effect on the growth of larvae of S. frugiperda compared to a diet of leaves of Ricinus communis, a species that did not have negative effects on this moth; more valuable plant parts, such as young leaves, flowers, and unripe fruits with seeds, have higher scopolamine concentrations than other tissues; leaves of B. suaveolens increase their content of scopolamine after artificial damage. The highest induction was found 24 hr after the damage, and after that, scopolamine content decreased to constitutive levels. This increase represented a cost, because in another experiment, a treatment with methyl jasmonate, an elicitor hormone, increased scopolamine production 9.5-fold and decreased leaf growth 2.3-fold; a diet of artificially damaged leaves of B. suaveolens showed a negative effect on the growth of larvae of S. furgiperda compared to undamaged leaves, suggesting that damage by herbivores induces resistance. Our data are in line with the optimal-defense theory, but experiments in the field with herbivores that share an evolutionary history with B. suaveolens must be undertaken to understand the dynamics of TA allocation in response to herbivory.

Assessment of seasonal dry‐matter yield and quality of grass swards with imaging spectroscopy

AbstractThe potential of imaging spectroscopy for the assessment of seasonal dry‐matter (DM) yield and sward quality was studied. Relationships between spatial heterogeneity of tiller density, light interception, ground cover and seasonal DM yield were developed. Sward heterogeneity was quantified by the spatial standard deviation of ground cover and of logarithmically transformed ground cover, and patterns in ground cover transects were quantified by wavelet entropy. An experiment was conducted with eight control (C) swards, eight naturally damaged (ND) swards and twelve artificially damaged (AD) swards. Swards were established in containers and spectroscopic images were recorded twice weekly.Seasonal DM yield was linearly related to a combination of means of ground cover and index of reflection intensity (r2 = 0·93). Spatial variation of tiller density was larger for AD and ND swards than for C swards. Values of the spatial standard deviation of ground cover and wavelet entropy were larger for AD and ND swards than for C swards. A single spatial standard deviation of ground cover value of 13% discriminated ND and AD swards from C swards. Seasonal means of wavelet entropy (r2 = 0·70) and the spatial standard deviation of ground cover (r2 = 0·63) at harvest were linearly related to seasonal DM yield. It is concluded that imaging spectroscopy can be used for assessing seasonal DM yield and sward heterogeneity.

Variation in damage to cotton affecting larval feeding preference of Spodoptera littoralis

AbstractFeeding experiments with larvae of Spodoptera littoralis were performed with leaves from cotton plants subjected to damage and from undamaged plants. In the experiments, four different time intervals (1, 3, 7, and 14 days) after damage induction and two different levels (high and low) of herbivore damage were tested. Seven days after damage induction larvae fed less on the young top leaves from damaged plants for both levels of damage. At the high damage level, the larvae fed less on leaves from the damaged plants after just three days, and this effect still remained 14 days after damage infliction. When mature leaves from the middle of the plant were compared, no difference between treatments was observed.Two plant sizes were tested, small plants with 4–5 true leaves and large plants with 8–10 true leaves. In small plants the induced changes affecting larval feeding were found mainly in the youngest leaf at the top of the plant, while in large plants the induced effects were found in both the youngest and the second youngest leaves.In plants subjected to artificial damage, larvae fed less on top leaves of the damaged plants when compared to leaves from undamaged plants. When leaves from plants that had been artificially damaged were directly compared with leaves from plants damaged by herbivores, larvae fed more on the youngest leaves from artificially damaged plants when the plants were large. In small plants no significant difference was found when comparing artificial and herbivore damage.

Volatiles released in succession from artificially damaged ashleaf maple leaves

Leaves of the ashleaf maple seedlings (Acer negundo Linn.) were artificially damaged, and the blends of volatiles were detected with gas chromatography–mass spectrometry. As we will show here, some compounds that had been detected in insect-infested plants are induced by artificial damage without insect oral secretion. Among them, two acyclic monoterpenes are emitted several hours after damage, and two cyclic monoterpenes reached their highest concentration within a day. Two diesters, dimethyl adipate and di-isobutyl succinate, were induced by the damage. However, the so-called C 6 green leafy volatiles, except (Z)-3-hexenyl acetate, were not detectable. A heterocyclic compound, benzothiazole, was induced in this species. After wounding, the volatiles were emitted in a time-dependent manner. The amount of induced volatiles collected in August was less than that in July due to seasonal difference, but the changing pattern of induced compounds did not differ significantly.

潮風害による樹勢低下ウンシュウミカン樹における光合成産物の転流・分配特性

The distribution characteristics of 13C-labeled photosynthate and sink strength of each organ in damaged satsuma mandarin (Citrus unshiu Marc.) trees, caused by briny wind of Typhoon No.19, November 1991, were studied during the recovering stage using naturally and artificially damaged trees. The damaged trees were separated into 3 groups, according to the degree of defoliation after the storm, that is, severe (70-80% of defoliation rate), modest (30-50%) and light damage (10-20%). The more severe, briny wind-damage the trees experienced, the more defoliation and root decay occurred. The most severely damaged trees had the highest shoot/root ratio, 2.0 the following season. Nine months after the natural damage (July, 1992), about 60% of 13C-labeled photosynthate was partitioned into fine and small roots in the most severely damaged and fruit-thinned trees. It is supposed that the photosynthate was mostly consumed to accelerate rooting and for elongation of fine and small roots. Half a month after incurring artificial damage by fruit-thinned trees in October, spring flush leaves, 2- and 3-year-old twigs, roots, and old leaves accumulated most of the photosynthates, whereas in fruit-bearing trees, regardless of defoliation rate, the crop amassed 40-50% of the dry matter and absorbed much of the 13C administered. These results indicate that the fruit which has a very high sink strength diverted photosynthates necessary for growth and respiration of fine roots. Thus, fruit-bearing is an important factor in the recovery of damaged trees.

Volatile compounds induced by herbivory act as aggregation kairomones for the Japanese beetle (Popillia japonica Newman)

The Japanese beetle is a polyphagous insect that typically aggregates on preferred host plants in the field. We studied the response of Japanese beetles to artificial damage, fresh feeding damage, and overnight feeding damage to test the hypothesis that beetles are attracted to feeding-induced volatiles. Crabapple leaves that had been damaged overnight by Japanese beetles or fall webworms attracted significantly more Japanese beetles than did undamaged leaves. Artificially damaged leaves or leaves freshly damaged by Japanese beetles, however, were not significantly more attractive than undamaged leaves. Leaves that had been damaged overnight by Japanese beetles or fall webworms produced a complex mixture of aliphatic compounds, phenylpropanoid-derived compounds, and terpenoids. In comparison, artificially damaged leaves or leaves with fresh Japanese beetle feeding damage generated a less complex blend of volatiles, mainly consisting of green-leaf odors. Feeding-induced odors may facilitate host location and/or mate finding by the Japanese beetle.

Induced changes in the indole glucosinolate content of oilseed and forage rape (Brassica napus) plants in response to either turnip root fly (Delia floralis) larval feeding or artificial root damage

AbstractPlants from two cultivars of forage rape and one cultivar of oilseed rape were inoculated with turnip root fly (Delia floralis) eggs at either 4 or 6 weeks prior to harvest, or, alternatively, were artificially damaged by mechanically removing approximately one‐third of the root volume. Larval damage increased the total glucosinolate content of the roots. In contrast, artificial damage reduced the total glucosinolate content of the roots, with the levels decreasing as the time interval between damage and harvest lengthened. Turnip root fly larval damage also modified the glucosinolate composition of the roots, with the proportion of indoleglucosinolates increasing significantly. No such changes were observed in the artificially damaged roots. Neither type of damage appeared to affect the total glucosinolate content of foliar samples significantly, when averaged over all cultivars, but it was of interest to note that the proportion of glucobrassicin present in the leaves of the oilseed rape cultivar, Ariana, was consistently greater in both the larval and artificially root damaged plants compared with undamaged plants of the same cultivar. These results are discussed in relation to sulphur availability and the validity of root trimming as a simulation for turnip root fly damage.

Calculating EM anomalies in a resistive environment by the CARMEN program

Artificial damage was introduced in stainless-steel cladding layer (SSCL) of stainless-clad bimetallic steel bars (SCBSBs) to simulate the initial imperfection. The corrosion performances and mechanical properties of SCBSBs were investigated experimentally. Based on the test results of corrosion performance of artificially damaged SCBSBs, corrosion mainly occurred in the damaged area. The wc developed faster than the dc, with increases in corrosion ratio. The increment in corrosion ratio led to decreases in fy, fu, εu and δ. Predictive equations were proposed to quantify influences of corrosion on fy, fu, εy, εu, εu/εy and δ. A stress-strain model was proposed to clarify mechanical properties of artificially damaged SCBSB specimens with various corrosion ratios. The comparisons among different steel bars were conducted to investigate differences in effects of corrosion on mechanical properties. Different energy indexes were calculated to quantify the ductility of artificially damaged SCBSB specimens comprehensively. The finite element analysis was carried out to investigate the effects of corrosion morphology and location on strength properties of SCBSBs. Based on numerical results, when corrosion ratio was the same, the fu and fy of corroded SCBSBs increased, with the increase in W/D. The effect of corrosion location on strength properties of corroded SCBSBs could be ignored. Contributions of this study were useful to determine resistance of structures with SCBSBs during the service life accurately.

Thermoluminescence emission spectra of mineral epidote

Thermoluminescence (TL) emission spectra of epidote samples from different locations, with varying amounts of damage from the decay of their U and Th contents, have been studied in the visible region at various glow temperatures. The effect of artificial damage produced by high fluences of ∼ 30 MeV α-particles has also been examined. A strong anticorrelation is observed between the wavelength-dependent intensity ratio (400–500 nm emission: total glow) and the natural radiation damage (as measured by the fossil fission track density); while in artificially damaged crystals the opposite effect is observed. One possible explanation for this contradiction is that it may be associated with crystallographic changes caused by the high preannealing temperatures (800°C for 6 h) applied to the sample before α-particle irradiation, since X-ray diffraction studies show a significant difference in the structural parameters of the naturally damaged and artificially damaged crystals. Alternatively, radiation damage resulting from the decay of the Th content of the crystals (not manifested by the fossil fission tracks) may be responsible for the above-mentioned contradiction.