Stem Shape Research Articles

Comparative Anatomical, Histochemical, and Phytochemical Characterization of Species of the Genus Cucumis L.

Cucumis anguria L. and Cucumis dipsaceus Ehrenb. ex Spach belong to the Cucurbitaceae family and are popularly known as "maxixe." In folk medicine, they are used to treat pneumonia, hyperglycemia, wounds, and malaria. This study aims to characterize the anatomy, histochemistry, and phytochemistry of C. anguria and C. dipsaceus. Conventional methods in plant anatomy and microscopy were used to prepare and analyze semi-permanent slides containing cross-sections of the stem, petiole, leaves, and paradermal sections of the leaf blade. For the histochemical analysis, different reagents were used according to the target metabolite. Phytochemical tests of methanolic extracts of leaves were performed by thin-layer chromatography. The microscopic analysis allowed obtaining the differentiation of plant cells, the presence of tector and glandular trichomes, in addition to showing anatomical traits such as stem shape, petiole shape, and organization of the mesophyll. Histochemistry showed the presence of alkaloids, starch, phenolic compounds, lipophilic compounds, lignin, and tannins. Phytochemical prospection identified monoterpenes, sesquiterpenes, triterpenes, steroids, alkaloids, and reducing sugars. The obtained results provide important information for quality control and species differentiation since there are few studies in the literature on these species.

DOES RESIN TAPPING AFFECT THE TAPERING AND ACCUMULATION OF MERCHANTABLE TIMBER VOLUME IN PINE TREES?

Form factors and taper functions are used for the quantitative and qualitative description of tree stem shape. In southeastern Mexico, there are plantations of Pinus caribaea var. hondurensis (Sénécl.) W.H. Barrett & Golfari, Pinus elliottii var. elliottii Engelm., and hybrids between these species to simultaneously produce resin and wood. Farmers need to know whether the practice of resin tapping to death has a negative impact on tree shape and volume of the wood produced. To answer these questions, this study compared the shape, taper, and volume of resin-tapped and untapped trees from three P. caribaea origins. A total of 198 trees (99 resin-tapped and 99 untapped) were measured in all diameter categories of the plantation. Total volume models, along with a compatible taper system and variable merchantable timber volume, were fitted using linear and nonlinear regression analyses. To compensate for the lack of initial tree size data prior to tapping, indicator variables (dummies) and an additive structure were used to parameterize volume and taper models. Untapped trees accumulated greater volume than tapped trees. In contrast, the form factor (ff) of resin-tapped trees (ff = 0.51) was greater than that of untapped trees (ff = 0.45). The form factor increased due to tapping between 4 and 7 % depending on the origin, although the hybrid P. caribaea × P. elliottii presented the most desirable stem geometry in tapped and untapped trees. Based on the Demaerschalk model, the variability is estimated at 99 and 97 % of the merchantable and taper volumes, respectively.

Variation and Phenetic Relationship of Passiflora spp. in Yogyakarta Based on Morphological and Anatomical Characters

Passiflora spp. or passion fruit is a tropical plant that is often used as a food source. The large morphological variations of Passiflora cause difficulties in identifying the species. The objectives of the study are to identify the specific morphological and anatomical characters of Passiflora spp. in Yogyakarta and to determine their phenetic relationship for identification. A total of 15 samples of Passiflora were taken by purposive sampling technique from Bantul, Sleman, Kulon Progo, and Yogyakarta City, and then carried through the morphological and anatomical characterization. The morphological characters observed stems, leaves, and flowers, while the anatomical characters observed leaves. The results show that the observed samples are identified as four species, P. foetida, P. vitifolia, P. edulis, and P. quadrangularis. The P. edulis species consists of two forms, P. edulis f. flavicarpa and P. edulis f. edulis. The variation of morphological character lie in young stem shape, leaf shape, the texture of stem and leaf surface, bract shape and color, sepal and petal color, and the presence of a purple corona ring. While the variation of anatomical characters lie in the pattern of the vascular bundles, the shape of the upper and lower sides of the leaf veins, the shape and size of the palisade cells, as well as the type and density of stomata. Based on the phenetic analysis on the 0.8 phenon line, four main clusters were formed, P. foetida, P. vitifolia, P. edulis, and P. quadrangularis.

A Precise Segmentation Algorithm of Pumpkin Seedling Point Cloud Stem Based on CPHNet.

Accurate segmentation of the stem of pumpkin seedlings has a great influence on the modernization of pumpkin cultivation, and can provide detailed data support for the growth of pumpkin plants. We collected and constructed a pumpkin seedling point cloud dataset for the first time. Potting soil and wall background in point cloud data often interfere with the accuracy of partial cutting of pumpkin seedling stems. The stem shape of pumpkin seedlings varies due to other environmental factors during the growing stage. The stem of the pumpkin seedling is closely connected with the potting soil and leaves, and the boundary of the stem is easily blurred. These problems bring challenges to the accurate segmentation of pumpkin seedling point cloud stems. In this paper, an accurate segmentation algorithm for pumpkin seedling point cloud stems based on CPHNet is proposed. First, a channel residual attention multilayer perceptron (CRA-MLP) module is proposed, which suppresses background interference such as soil. Second, a position-enhanced self-attention (PESA) mechanism is proposed, enabling the model to adapt to diverse morphologies of pumpkin seedling point cloud data stems. Finally, a hybrid loss function of cross entropy loss and dice loss (HCE-Dice Loss) is proposed to address the issue of fuzzy stem boundaries. The experimental results show that CPHNet achieves a 90.4% average cross-to-merge ratio (mIoU), 93.1% average accuracy (mP), 95.6% average recall rate (mR), 94.4% F1 score (mF1) and 0.03 plants/second (speed) on the self-built dataset. Compared with other popular segmentation models, this model is more accurate and stable for cutting the stem part of the pumpkin seedling point cloud.

Biomechanical Comparison of Impaction Techniques and Cross-Sectional Femoral Stem Shapes for Cementless Total Hip Arthroplasty.

Traditional mallet broaching and stem seating in cementless total hip arthroplasty (THA) can result in femoral stem misalignment, potentially reducing implant longevity. This study aimed to compare the pullout strength of cementless THA femoral stems with different cross-sectional designs achieved through the powered impactor method versus the traditional mallet method. The authors utilized 24 polyurethane foam femurs and two femoral bone preservation stems with different proximal cross-sectional shapes (double taper: ACTIS®, size 5; flat taper: TRI-LOCK®, size 5). A single orthopedic surgeon broached each femur from size 0 to size 5 using either the powered impactor or mallet impaction methods. Broaching time and component implantation times were recorded. A load-to-failure pullout strength test was conducted, and the ultimate pullout load was recorded. The broaching time for the TRI-LOCK® stem showed a statistically significant difference between the two impaction methods (powered: 37±7 seconds, mallet: 75±29 seconds, F[3, 20] = 4.56, p = 0.002), but no statistically significant difference was detected for the ACTIS® stem between the two impaction methods (powered: 47±22 seconds, mallet: 59±9 seconds, F[3, 20] = 4.56, p = 0.304). There was a statistically significant difference in pullout strength between the two impaction groups, and this strength was influenced by the implant cross-sectional shape (ACTIS®: 774±75N versus 679±22N, F(3,20) = 16.38, p = 0.018; TRI-LOCK®: 616±57N versus 859±85N, F(3, 20) = 16.38, p <0.001). The technique used for femoral bone preparation (powered impactor versus mallet) and the cross-sectional design of the cementless femoral stem are crucial factors that affect initial stem stability and operation time.

Flax lines of hybrid origin homozygous for genes of chlorophyll coloration and other morphological traits in the VIR flax genetic collection

Due to climate change and the industrialization of agriculture, the role of genetic collections is increasing. The paper characterizes 41 flax lines with mutations regarding chlorophyll coloration from the VIR genetic collection: 5 parental lines created on the basis of the VIR global flax collection, and 36 recombinant ones.Among the 36 created recombinant lines, homozygous for two or more genes of morphological traits, there are those with chlorophyll deficiency and differences in anthocyanin color, stem shape and ciliation of the septa of the boll. Anthocyanin coloration and other morphological features were controlled by one or two of the 22 genes identified by us. Four of the recombinant lines were also homozygous for two or three independent chlorophyll coloration genes.It was established that the genes of chlorophyll coloration and 22 genes controlling other morphological features act independently.The ygp1 and ygp2 genes do not have a significant effect on most economically valuable traits, except for early flowering, and can be used for labeling varieties.The genes s1, YSED1, ysed2 and rs1, which determine the yellow seed color, are necessary for the creation of flax varieties for food purposes, which makes the 11 lines based on these genes in demand for breeding purposes.In flax, the molecular genetic function of none of the chlorophyll coloration genes is known, so the created genetic collection will be in demand to solve this problem.

Characterization of anatomical characters of Peperomia (Piperaceae) from Asia for taxonomy

Abstract The flowers of Peperomia (Piperaceae) are simple, minute, and unique structures within the angiosperms consisting of a rounded bract, two stamens and an ovary, but generally lack taxonomic value at species level. Because of this, morphological characters of vegetative parts have been mainly used for species level taxonomy. There is a need to supplement these vegetative characters with anatomical characters. We selected 17 native Thai species representatives of South East Asian Peperomia to investigate the utility of vegetative anatomical characters for species delimitation, taxon identification, and classification. Stem, petiole, and leaf anatomical characters were studied using standard microscopic techniques. The anatomical characters demonstrated high diversity and supported species identification. Unweighted Pair Group Method with Arithmetic Mean (UPGMA) culstering, Principal Coordinates analysis (PCoA), and Principal Component Anaysis (PCA) were used to investigate patterns in the multivariate anatomical data and identify groupings of value to species classification. Four broad groupings were retrieved and some subgroupings identified. The most important characters that differentiated the species in the multivariate analysis included stem shape (roundness and ridges), petiole indumentum and trichome type, vascular bundle pattern and number, stem pith cavity, mucilage canals, and stem cortex sclerenchyma. These data were further used to prepare anatomical descriptions at generic and species levels and to provide a key to species.

Zhodnocení růstu proveniencí borovice černé (Pinus nigra Arnold) ve středních Čechách ve věku 51 let

The paper contains the evaluation of 9 European black pine provenances on the research trial No. 41 – Roblín (Czech Republic) at the age of 51 years. The tested provenances originated from Bosnia and Herzegovina, Serbia, Croatia, Bulgaria, Greece, France and Slovakia. The evaluation is based on an assessment of following factors: total height, dbh, stem form, health state, defoliation, diameter of main branches, stem damage, crown density, twisted growth, stem nature pruning, cross-section, and taper. Obtained data sets were statistically analysed. The best growth both in quantitative and qualitative traits was recognised for the provenance 9 – Les Barres, Oise (France), which was excellent in height growth, health status and stem shape, and also for the Serbian provenance 2 – Crni Vrh, Titovo Užice, which excelled not only in growth rate, stem shape and health status, but also in diameter of main branches. Less suitable provenance seem to be 3 – Prušačka Rjeka, Banja Luka from Bosnia and Herzegovina (worse growth, stem nature pruning, cross-section and taper) and Croatian 5 – Južna Kandija, Osijek (worse growth, stem shape, and health). The most important for explaining the differences between provenances were the diameter at the breast height, crown density and defoliation.

Vyhodnocení provenienční plochy IUFRO s jedlí obrovskou na lokalitě Drahenice ve středních Čechách ve věku 41 let

The paper deals with growth and prosperity of 25 provenances of grand fir from Washington, Oregon, Idaho and Montana (USA), and from Vancouver (British Columbia, Canada) tested in the international provenance research trial No. 212 – Drahenice (Czech Republic; N49° 31‘ 10‘‘, E13° 57‘ 20‘‘, 570 m a.s.l., acidic beech site). Biometric measurements took place at the age of 41 years; qualitative features were visually assessed according to the IUFRO methodology. The best overall assessment of both production and quality shows provenance 12041 – Oyster Bay (BC). Other provenances with high growing stocks, i.e. 12005 – Bear Mountain (WA), 12038 – Clearwater (ID), 12043 – Sproat Lake (BC) and 12044 – Kaye Road (BC) showed some qualitative shortcomings (lower vitality, worse stem shape or thicker branches). The worst both in production and quality were provenances 12020 – Crescent Creek (OR) and 12011 – Clear Lake (WA). The results confirm the suitability of the current setting of the rules for the transfer of reproductive material from North America to the Czech Republic.

Growth and quality of 16-year-old sessile oak (Quercus petraea (Matt.) Liebl.) planted in traditional and alternative row planting patterns

Abstract Traditional oak silviculture is costly due to high initial planting density required to obtain management goals of producing high quality timber. New methods therefore reduce the initial planting density and use a planting pattern that allows the inclusion of naturally regenerated trees of other species. The study presents the results of a 13-year experiment on the growth and quality of sessile oak planted in traditional and three alternative planting patterns. We hypothesized that increasing of initial spacing and use of natural regeneration to compensate for lower intra-specific competition does not deteriorate growth and quality parameters of oak. Breast height diameter, height, slenderness, height of the first live branch, diameter of the thickest branch, stem shape and potential future crop oak trees (PFCT) were measured and analysed. The local competition of admixture species was estimated on the basis of the relationship between the height of the oak and the height of admixture trees in its close proximity. The type of planting pattern had no significant effect on oak diameter, but oak height was greater in the traditional pattern than in alternative patterns. Height of the first live branch was the only qualitative trait that differed significantly between the compared planting patterns. The probability of an oak being selected as a PFCT was similar in traditional and alternative patterns, but PFCT absolute number was increasing with an increase of oak planting density. Analysis of competition of admixture species in alternative methods shows that it can reduce height, diameter and stability of oaks. On the other hand, the probability of trees being selected as a PFCT increases significantly with increasing interspecific competition. We conclude that, with controlled competition and at least moderate natural regeneration, the alternative planting patterns can produce oaks with similar growth and quality to those in the traditional pattern.

Comparative taxonomical, biological and pharmacological potential of healthy and geminivirus infected leaves of Hibiscus rosa-sinensis L.: First report

In the present research project, the first report on comparative analysis of the taxonomical, biological and pharmacological potential of healthy and geminivirus infected Hibiscus rosa sinensis (L.) leaves of the family Malvaceae was done by using different micro and macroscopic techniques. First of all, leaves were characterized for Cotton leaf curl Multan virus (CLCuMuV) and its associated betasatellite (Cotton leaf curl Multan Betasatellite; CLCuMB). Different morphological parameters like shape and size of stem, leaves, seeds and roots, presence and absence of ligule, distance between nodes and internodes and type of inflorescence etc. were analyzed. CLCuMuV infected H. rosa-sinensis revealed systematic symptoms of infection like chlorosis of leaves, stunted growth, decrease in size of roots, shoots and distortion etc. Anatomical investigation was performed under light ad scanning electron microscope. Different anatomical features like length and shape of guard cells, subsidiary cells, presence or absence of stomata, secretory ducts and trichomes were examined. In both plant samples anomocytic types of stomata and elongated, non-glandular and pointed tip trichomes were present, but the size (especially length and width) of trichomes and other cells like epidermal, subsidiary, and guard cells were highest in virus infected plants likened to healthy one. In the antibacterial activity, the maximum antibacterial potentail was seen in methanolic extract of K. pneumonea while antifungal activity was shown by methanolic extract of A. solani. Plants interact with different biological entities according to environmental conditions continuously and evolved. These types of interactions induce changes positively and negatively on plant metabolism and metabolites production. Many plant viruses also attacked various host plants consequently alter their secondary metabolism. To overcome such virus infected plants produces many important and different types of secondary plant metabolites as a defense response. Subsequent analysis of this n-hexane plant extract using Gas chromatography mass spectroscopy technique revealed that Hibiscus eluted contained 10 main compounds in Healthy sample and 13 compounds in infected one. Presence of essential secondary metabolites were also analyzed by FTIR analysis. The present study provides a comprehensive and novel review on taxonomy (morphology, anatomy) and antimicrobial potential of both healthy and geminivirus infected H. rosa-sinensis.

Characterization And Yield Testing Of Two Prospective Varieties And Three Comparative Varieties Of Kyuri Cucumber (Cucumis Sartivus L.) In The Highlands

Cucumber (Cucumis sativus L.) is one type of vegetable from the cucurbitaceae family that has been grown by farmers in Indonesia. The research was conducted for 4 months from September 23 to December 13, 2022 in one of the experimental fields owned by PT Aditya Sentana Agro. The purpose of this study was to determine whether the 2 candidate varieties CI-88 and CI-87 of kyuri cucumber tested would show significant differences in characters from 3 comparison varieties F1 MK 01, F1 MK 02, F1 MK 03 and to determine whether the results obtained from the 2 candidate varieties CI-88 and CI-87 of kyuri cucumber to be used as varieties and produced. This study consisted of 2 genotypes of hybrid variety candidates CI-88 and CI-87 and 3 comparison varieties namely F1 MK 01, F1 MK 02 and F1 MK 03 which were used as treatments. The three comparison varieties were used because they were in high demand in the market so that they had a high selling value and had a good response from farmers. Qualitative characteristics observed were stem shape, leaf shape, flower color, fruit shape, fruit skin color, fruit flesh color, and fruit taste test. The results of observations of qualitative character traits are presented in the form of tables and picture documentation. The results of quantitative characterization observations include stem diameter, fruit weight per plant, fruit weight per fruit, fruit diameter, fruit length, number of fruits per plant, leaf width, leaf length, age from flowering and age from harvest. The results of the two candidate varieties tested have the opportunity to be developed and registered as new varieties because the results obtained are comparable to the comparator varieties already on the market..

Stem shape and structural complexity change in beech forests along a management gradient

For about half a century, attempts have been made to manage forests as close to nature as possible. This management targeted the creation of structures that resemble those found in primary forests. Laser scanning provides the opportunity to quantify such structural “naturalness” and allows to evaluate which management practices come closest to forest structures found in primary forests. In this paper, European beech (Fagus sylvatica L.) forests with different management intensity were compared to primary forests in terms of their structural complexity and the shape of tree stems. For this purpose, data from mobile and terrestrial laser scans (MLS and TLS) of managed forests, of forests whose management has been abandoned, and of primary forests was used. We found that management intensity influenced the distribution of plant material in the forest stand and thus the structural complexity on stand level. Also, management affected the shape of the stems. Here, it is important to consider the management history of the forest stands and the forest development phase in which management was abandoned. The stem shapes of trees in primary forests were significantly different (larger stem diameters and longer branch free boles) from those of the other investigated forests. Nevertheless, our results showed that it is possible to achieve old-growth-like structures such as high standing volumes, a multi layered canopy, high number of large trees and high variation in tree size and age through targeted silvicultural treatments in order to accelerate the close-to-nature development of forests. The present study illustrates the possibility of using mobile and terrestrial laser scanning to objectively compare and evaluate the structural effects of different silvicultural concepts.

Virgin cork colour and porosity as predictors for secondary cork industrial quality

Currently, the selection of the trees to be removed in a thinning, carried out in a young cork oak plantation, is determined by a systematic rule to reach a predefined tree density value, in combination with simple criteria regarding individual tree sanitary conditions and stem shape. Since no criteria regarding the cork are available, thinnings can result in the removal of individuals that would later produce high quality secondary cork, leaving tree producers with lower quality cork. This study aims to test the feasibility of using CIELAB colour space coordinates and porosity values, measured in virgin cork samples, as predictors of the industrial cork quality and porosity obtained in secondary cork, thereby providing additional information usable for the classification of trees prior to the first thinning implementation. The L* and b* colour coordinates, measured in the transverse direction, depicted three main cork quality groups. Other L* and b* colour parameters, measured in the radial direction or in the cork back surface, have also shown statistically different average values while measured in different quality cork samples. Cork porosity from virgin and secondary cork showed a positive moderate monotonic relationship. A hyperbolic model for the prediction of secondary cork porosity was developed based on the virgin cork porosity, with one parameter expressed as a function of virgin cork colour coordinates (R2 =0.445). Results were successful in confirming the hypothesis raised. They may be used for the classification of trees prior to thinning.

Registration certificate for local variety of curly red chili Pengkol Jati from Grobogan, Central Java, Indonesia

Pengkol Jati curly red chili is a local variety of chili from Grobogan Regency, Central Java that has been grown by farmers for decades. A certificate of ownership of local varieties issued by Center for Crop Variety Protection and Agricultural Licensing, Ministry of Agriculture of Republic Indonesia is very important to protect the variety from illegal name and to meet the requirements for the release of varieties. The primary requirement to get the certificate of ownership is morphological identification, which was conducted in February to April 2020 in Pengkol Jati village, Grobogan regency. The character observed include external appearance of tree (height, growth, head shape, crown, branching, color on the book, canopy, stem shape and color), leaves (shape, size, direction, leaf color, size and color petiole, wax layer), flower (color of flower; stem; and flower crown, stain, petals, pistil head,position and angle of flower stalk, number of flower per node, flowering schedule, time of flower to fruit,), fruit (color, size, shape, skin and flesh thickness, fruit weight, seed color, shape, and size), and general data. The morphological characteristics and general data were noted and organized in the form of a standard blank and registered to Center for Crop Variety Protection and Agricultural Licensing to get a Certificate of Ownership of Local Varieties. Result of the experiment revealed that in 18 December 2020, a Certificate of Ownership of Local Varieties of Pengkol Jati curly red chili numbered: 1609/PVL/2020 was issued and submitted to local government of Grobogan regency.

An improved displacement adjustment method for overlarge deformation of valve at the cryogenic temperatures

Cryogenic valves are mostly designed at the room temperatures and served at the cryogenic temperatures. The wide temperature difference between design and service conditions causes the overlarge deformation of the valve stem structure, resulting in the cryogenic valve prone to leakage, stuck and other unsafety issues. In this study, an improved displacement adjustment (IDA) compensation method is proposed to solve the problem of size over-tolerance and shape deformation of the valve stem at the cryogenic temperatures. The shape of the valve stem is redesigned by combining IDA and the finite element method to meet its ideal service requirements under the cryogenic conditions. One of the features of the IDA method is to optimize the compensation direction by considering the angle change of normal vector on valve stem surface. Another is to improve the iteration efficiency by recognizing the compensation factor through the Lagrange interpolation algorithm. The simulation and experimental results show that the proposed compensation method can effectively reduce the size and shape deviation of the valve stem. Therefore, this study provides a new method to reduce the stem deviation at the cryogenic temperatures by the shape compensation, which has reference significance for the design of other low temperature components.

Automatically Extracting Rubber Tree Stem Shape from Point Cloud Data Acquisition Using a B-Spline Fitting Program

Natural rubber is an important and strategic raw material, used in tires, gloves, and insulating products, that is mainly obtained by cutting the bark of rubber trees. However, the complex contour curve of the rubber tree trunk is hard to fit using a tapping machine. Thus, a trunk contour curve collection would be useful for the development of tapping machines. In this study, an acquisition system based on laser-ranging technology was proposed to collect the point cloud data of rubber tree trunks, and a B-spline fitting program was compiled in Matrix Laboratory (MATLAB) to extract the trunks’ contour curves. The acquisition system is composed of power, a controller, a driver, a laser range finder, and data transmission modules. An automatic extraction experiment on the contour curves of rubber tree trunks was carried out to verify the feasibility and accuracy of using the acquisition system. The results showed that the degree of rubber tree trunk characteristic recognition reached 94.67%, which means that the successful extraction of the rubber tree trunk contour curves and the B-spline fitting program are suitable for the extraction of irregular curves of rubber tree trunks. The coefficient of variation of repeated collection was 0.04%, which indicates that changes in relative positions and acquisition directions have little influence on the extraction and the accuracy of the acquisition system, which are high and stable. Therefore, it was unnecessary to adjust the position of the acquisition device before the collecting process, which helped to improve the efficiency of acquisition considerably. The acquisition system proposed in this study is meaningful to the practical production and application of agroforestry and can not only improve the precision of the rubber tapping process by combining with an automatic rubber tapping machine but can also provide technical support for the prediction of rubber wood volume and the development of ring-cutting equipment for other fruit trees.

Morphological Variations of Nepenthes mirabilis (Lour.) Druce in the Peat Swamp Habitat

Nepenthes mirabilis is a type of lowland Nepenthes. Nepenthes mirabilis has morphological variations in size and color in its natural habitat. This study was conducted with the aim to determine the morphological variations of Nepenthes mirabilis in peat swamp habitat including stems, leaves and pitchers. This research was carried out in Pulu Beruang Village, Tulung Selapan District, Ogan Komering Ilir, South Sumatera. The research method used exploration method. Determination of the observation sample using a random plot method selected by purposive sampling. The parameters observed in this study were the morphological characteristics of Nepenthes mirabilis stems, leaves and sacs as well as environmental factors. Research results, Nepenthes mirabilis has a round stem shape (teres), red and green in color. The leaves are lanceolate, stalked, the edges of the leaves are flat and smooth, the upper surface of the leaves is green or reddish. Waist-shaped pouch, yellowish green in color with red striated and green with red spots.

Форма стволов и динамика продуктивности плантационных культур сосны обыкновенной разной исходной густоты

Исследованы динамика прироста, форма и объем стволов 42-летних искусственных насаждений сосны обыкновенной разной густоты, выращенных на осушенном болоте с применением удобрений в среднетаежной подзоне Карелии. Помимо инструментальной таксации древостоя в каждом варианте у 10 учетных деревьев изучено изменение диаметра на относительных высотах до 0,8Н с помощью теодолита 2Т30, среднеквадратическая ошибка которого (30") обеспечивает точность измерения диаметра 2 мм. Для детальной оценки динамики прироста со всех учетных деревьев были взяты керны буравом Пресслера на высоте 1,3 м. На момент исследования в варианте с посадкой 1 тыс. шт./га густота близка к исходной, а в остальных случаях сократилась в 2 раза. Основные различия между вариантами достигнуты в первые 20 лет роста насаждений, после чего ширина годичных колец во всех вариантах опыта практически сравнялась и затем к 30 годам стабилизировалась на уровне 1 мм. Расчет коэффициентов формы стволов показал статистически достоверные различия между вариантами с минимальной и максимальной густотой только для коэффициентов q 2 и q 3, характеризующих середину и верхнюю часть ствола. Для более детального исследования формы стволов зависимость абсолютных и относительных диаметров от относительной высотыаппроксимировали полиномами 6 и 5 степени. Уровень детерминации полученных регрессионных уравнений R 2 = 0,94-0,96. Подстановка в эти уравнения одинаковых значений высоты (17 м) и диаметра на высоте груди (20 см) показала, что объем ствола в вариантах с исходной густотой 2 и 4 тыс. шт./га выше на 7 и 12%, по сравнению с самой редкой посадкой, и на 18-25% выше, по сравнению с принятыми для региона сортиментными таблицами. Полученные результаты дают серьезные основания для корректировки нормативной базы оценки лесосечного фонда. The stem form and growth dynamic in the 42 years old artificial Scotch pine stands of various density are investigated. These stands are planted on the drained swamp with use of fertilisers in mid-taiga subzone of Karelia. On each sample plot ordinary stand measurement was made and on 10 sample trees stem diameters at relative heights (up to 0,8H) was measured using theodolite 2T30 which mean square mistake (30") provides the diameter measurement accuracy up to 2 mm. For more detailed growth assessment dynamics from each sample tree cores by Pressler's drill at the height of 1.3 m were taken. At the time of research on the plot with planting density of 1 thous/ha was similar to initial, and in other plots the density was reduced twice. The main distinctions between plots are reached in the first 20 years of growth after planting. After that year rings width in all stands of experience was practically equal and after 30 years was stabilized at the level of 1 mm. Calculation of stem form coefficients showed statistically reliable distinctions between plots with minimum and maximum density only for the coefficients of q2 and q3 characterizing the middle and the top stem parts. For more detailed research of stem form dependence of absolute and relative diameters on relative height was approximated using polynoms of 6 and 5 degrees. The determination coefficients of the received regression equations R2=0,94- 0,96. The substitution in these equations of identical values of height (17 m) and diameter at the breast height (20 cm) showed that stem volume in the stands with initial density 2 and 4 thous/ha is 7 and 12% higher in comparison with the plot of rare planting and 18-25% above in comparison with the assortment tables accepted for the region. The received results give the serious grounds for correction of regulatory base of an assessment of cut-down stands.

3D finite-element analysis of innovative coconut palm stem shaped headed shear connectors

Headed studs are shear connectors in composite structures used at the adjoining face of a steel beam and a concrete slab. In this research, the conventional shape of a headed stud was restructured to resemble the shape of a coconut palm stem (royal palm) without a change in the overall material volume, with the aim of improving the shear strength of the composite connection. Six innovative shear connectors for composite structures, named coconut palm stem royal shaped headed stud shear connectors (CPSR studs), were examined. Abaqus/Explicit was used to model a push-out specimen and the finite-element model was successfully validated using published experimental results. The six different CPSR studs encased in three grades of concrete (C40, C50 and C60) were tested for shear strength, stiffness and load–slip performance. The results for the innovative CPSR studs were compared with those for uniform cross-section headed studs; when embedded in C40, C50 and C60 grade concrete, the results showed, respectively, 35–41%, 37–44% and 41–52% improvements in the ultimate strength of the shear connection. The improved shear strength capacity of the CPSR studs without a change in the overall volume of stud material means that fewer studs are required, leading to economic benefits.