Experimental study on the stomatal resistance of green roof vegetation of semiarid climates for building energy simulations

Current modelling approaches for energy simulations in green roofs use a range of values for parameters such as stomatal resistance (rs) of the vegetation. rs reflects the capability of a plant to transpire, thus it has a direct relation to the cooling potential of green roofs in buildings. Therefore, rs values need to be revised based on differences among species and contrasting environmental conditions, considering anatomical and physiological characteristics among species and their changes throughout the day. In order to provide real data on species commonly used for green roofs in semiarid climates, this paper aims to evaluate the stomatal resistance of nine species of groundcovers and to compare this data with current models. rs was measured for each species at 8:00 h, 12:00 h, 16:00 h and 20:00 h during day and nighttime in winter in a leaf located at the middle of the stem. The results of this study showed that rs varies significantly among species, throughout the day and between the side of the leaf (adaxial or abaxial). The lowest rs values for species was at noon ranging from 264 to 807 s m- 1 and the highest rs was at night ranging from 568 to 973 s m-1. Sedum spurium red, Sedum hybrid, and white and pink Verbena sp. had the largest rs variation in the day-night cycle. The results of rs are higher than those values recommended for some energy simulation models

Vegetation survival and condition in public green spaces after their establishment: Evidence from a semi-arid metropolis

Urban vegetation is generally exposed to adverse environmental conditions, such as high temperatures, compacted soils, low fertility, and a high pollutant concentration. The influence of biophysical and social factors on the survival and condition of trees and nontrees was analyzed using a census of plants in 37 green spaces of the Metropolitan Region of Santiago de Chile (MRS) several years after their establishment. The tree survival rate was higher (77%) than that of other species (24%). Survival was primarily explained by municipality management and species selection, but the relevance of these factors differed between trees and nontrees. Species with low water requirements outperformed species that were more sensitive to water stress. A high mechanical damage rate was observed, with 91% of trees showing severe or medium damage. Soil quality was better than expected, with a bulk density less than 1.0 g m(-3) and moderate and high levels of P, and only 8% of sites had low K levels. The N content was highly variable, but most of the sites had levels greater than 20 mg kg(-1), which indicates a trend of accumulation that is consistent with urban soils. More in-depth studies are required to establish the factors that explain plant survival in public spaces of the MRS, and irrigation monitoring is especially needed

Vegetation survival and condition in public green spaces after their establishment: Evidence from a semi-arid metropolis.

Urban vegetation is generally exposed to adverse environmental conditions, such as high temperatures, compacted soils, low fertility, and a high pollutant concentration. The influence of biophysical and social factors on the survival and condition of trees and nontrees was analyzed using a census of plants in 37 green spaces of the Metropolitan Region of Santiago de Chile (MRS) several years after their establishment. The tree survival rate was higher (77%) than that of other species (24%). Survival was primarily explained by municipality management and species selection, but the relevance of these factors differed between trees and nontrees. Species with low water requirements outperformed species that were more sensitive to water stress. A high mechanical damage rate was observed, with 91% of trees showing severe or medium damage. Soil quality was better than expected, with a bulk density less than 1.0 g m-3 and moderate and high levels of P, and only 8% of sites had low K levels. The N content was highly variable, but most of the sites had levels greater than 20 mg kg-1, which indicates a trend of accumulation that is consistent with urban soils. More in-depth studies are required to establish the factors that explain plant survival in public spaces of the AMS, and irrigation monitoring is especially needed

Vernalisation and photoperiod sensitivity in wheat: Impact on canopy development and yield components

Genetic variation in the VERNALIZATION1 (VRN1) and PHOTOPERIOD1 (PPD1) genes, which control the vernalisation and photoperiod response, underpin wheat adaptation to different environments. Near isogenic lines were used to investigate the role of allelic combinations of VRN1 and PPD-D1, including new alleles for VRN1-A1, on the length of developmental phases, dynamics of leaf and tiller appearance and yield components in complementary irrigated field trials relevant to low latitude wheat growing areas and controlled conditions. Allelic differences in VRN1 had a stronger effect on the duration of the vegetative phase, while photoperiod sensitivity at PPD-D1 lengthened the stem elongation phase (SE) by up to 23%. If a phase was lengthened, flowering was delayed. The level of response to daylength during stem elongation (SE) introduced by photoperiod sensitive alleles was dependent on the VRN1 composition and vernalisation status. A longer SE under short days was achieved by PPD1 sensitive genotypes when one VRN1 spring allele was present and plants were vernalised. The duration of SE was weakly related to spike dry weight m−2 at DC65 in the field but did not translate into higher grain number m−2. In the field, lines with two to three VRN1 spring alleles had shortest development phases, including SE, close flowering dates, sampled similar temperature environments at different stages, and achieved high yields. Yield advantage was explained by higher biomass, harvest index, grain number m−2 and thousand kernel weight. Genotypes with three winter VRN1 alleles were comparatively disadvantaged, with a longer vegetative phase placing SE under higher temperatures. Allelic differences in both genes caused large variation in leaf and tiller number generation but also in tiller mortality and individual leaf size, lessening the impact on leaf area. Changes in plant morphology and yield components that did not seem mediated via the influence of development genes on the duration of different stages and their impact on resource capture deserve further investigation

Modeling the effect of different forms of through discontinuities in the collapse behavior of metal pipes

190 σ.Η παρούσα διπλωματική εργασία ασχολείται με την μελέτη της αξονικής κατάρρευσης σωλήνων τετραγωνικής ή ορθογωνικής διατομής με τοιχώματα λεπτού πάχους και με οπές και σχισμές διαφόρων μεγεθών στο μέσον καθ’ ύψος των δοκιμίων. Μελετώνται δηλαδή μηχανισμοί απορρόφησης ενέργειας από τη σκοπιά των ατελειών. Η εργασία αυτή έχει κυρίως πειραματικό και ερευνητικό προσανατολισμό. Το κείμενο χωρίζεται σε δύο βασικά μέρη, το θεωρητικό και αυτό που έχει να κάνει με την πειραματική διαδικασία και διερεύνηση. Το πρώτο μέρος περιλαμβάνει τα κεφάλαια ένα και δύο, ενώ τα κεφάλαια τρία έως έξι αντιστοιχούν στο δεύτερο μέρος. Στο πρώτο κεφάλαιο γίνεται μια γενική αναφορά στις θεωρίες που εφαρμόζονται για τα δοκίμια ορθογωνικής διατομής με λεπτά τοιχώματα σχετικά με την αξονική τους κατάρρευση, καθώς επίσης εξηγούνται και διάφοροι βασικοί όροι. Περιγράφονται οι βασικοί όροι κατάρρευσης και καταγράφονται ορισμένα μαθηματικά μοντέλα που υπάρχουν για τη περιγραφή τους. Το δεύτερο κεφάλαιο ασχολείται με τις ατέλειες των δοκιμίων. Παρουσιάζονται θεωρητικά στοιχεία για τις τάσεις που αναπτύσσονται γύρω από οπές οι οποίες υπάρχουν σε μια μεταλλική επιφάνεια. Στο τρίτο κεφάλαιο περιγράφεται η πειραματική διαδικασία. Γίνεται παρουσίαση των δοκιμίων, της μορφής που αυτά έχουν, της διαδικασίας κατασκευής τους καθώς και των οπών/σχισμών πάνω σε αυτά. Επιπλέον περιγράφεται ο εξοπλισμός που χρησιμοποιήθηκε για την πειραματική διαδικασία καθώς και οι συνθήκες κάτω από τις οποίες έγιναν τα πειράματα. Στο τέταρτο κεφάλαιο περιγράφεται η μέθοδος των πεπερασμένων στοιχείων (FEM), γίνεται αναφορά στη γένεση πλέγματος, και στα είδη ανάλυσης που μπορούν να πραγματοποιηθούν με αυτή τη μέθοδο. Επίσης, περιγράφεται το πακέτο πεπερασμένων στοιχείων LS-DYNA και οι παράμετροι που επιλέχθηκαν στις προσομοιώσεις. Στο πέμπτο κεφάλαιο γίνεται η παρουσίαση όλων των προσομοιώσεων. Για κάθε δοκίμιο το οποίο συμπιέστηκε παρουσιάζονται οι φάσεις κατάρρευσης συγκριτικά με τις αντίστοιχες φάσεις των πειραμάτων, το διάγραμμα φορτίου – μετατόπισης, οι τελικές όψεις του δοκιμίου, και γίνεται μια περιγραφή του μηχανισμού με τον οποίο κατέρρευσαν τα δοκίμια. Στο έκτο κεφάλαιο ακολουθεί η σύγκριση των αποτελεσμάτων που προέκυψαν από τα πειράματα. Γίνεται γενική σύγκριση, αλλά και σύγκριση με βάση βασικών παραμέτρων που έχουν επιλεγεί. Μετά τη σύγκριση, στο έβδομο κεφάλαιο παρουσιάζονται τα συμπεράσματα που προέκυψαν από τα πειράματα και γίνονται ορισμένες προτάσεις για μελλοντική έρευνα που μπορούν να αποτελέσουν θέμα μελέτης του πεδίου των καταστροφικών καταπονήσεων. Τέλος, ακολουθούν δύο παραρτήματα, στο πρώτο παρατίθενται τα κατασκευαστικά σχέδια των δοκιμίων που κατασκευάστηκαν και στο δεύτερο η βιβλιογραφία που χρησιμοποιήθηκε για την συγγραφή της εργασίας, αλλά και την κατανόηση του αντικειμένουThis thesis deals with the study of the axial collapse of tubes of square or rectangular with thin walls and holes and cracks of various sizes at the middle height of the specimens . Studied ie energy absorbing mechanisms in terms of defects. This work is mainly experimental and research oriented . The text is divided into two major parts, the theoretical and this has to do with the experimental procedure and investigation. The first part contains chapters one and two, while chapters three to six correspond to the second part . The first chapter is a general reference to the theories applied to pieces of rectangular section with thin walls on the axial collapse , as well explained and several key terms . Describe the basic terms collapse and recorded some mathematical models exist for describing them . The second chapter deals with the imperfections of the specimens . Featured theoretical data for trends developing around holes that exist in a metal surface . The third chapter describes the experimental procedure . Becomes presentation of essays , the form they have , the manufacturing process as well as the holes / slots on them. Moreover describes the equipment used for the experimental procedure and the conditions under which the experiments were made . The fourth chapter describes the finite element method (FEM), referring to the genesis mesh and the kinds of analysis that can be performed with this method. Also described is the finite element package LS-DYNA and the parameters chosen in the simulations . The fifth chapter is the presentation of all simulations. For each specimen which was pressed out the steps collapse compared to the respective phases of the experiments , the diagram load - displacement, the end faces of the specimen , and we describe the mechanism by which collapsed cores . The sixth chapter is a comparison of the results obtained from the experiments . A general comparison, and comparison based on key parameters selected . After the comparison , in the seventh chapter presents the conclusions drawn from the experiments and made ​​some recommendations for future research that may be the subject of study of the field of destructive stresses. Finally , here are two appendices , the first design drawings listed specimens manufactured and second literature used for writing the work , but also the understanding of the subjectΔημήτριος Ι. Τόκη

Phenological cycle and floral development of Chloraea crispa (Orchidaceae)

Chloraea crispa Lindl. is a terrestrial orchid endemic to Chile that has potential to be a novel alternative for the cut flower industry. The objectives of this study were to describe the phenological cycle and floral bud development of C. crispa to determine the timing of initiation and differentiation of the spike. During the summer, plants are dormant. The renewal buds are located at the top of the rhizome, next to the buds from which the shoot of the previous season originated. From the end of summer until the end of winter, the plant is in vegetative growth. From June onward, the flower stalk starts to emerge, and flowering and leaf senescence occur during the spring until the beginning of summer. The renewal buds started forming leaf primordia during or after the flowering of the above-ground annual stems and the senescence of the plant. Between December and January, the apical meristem changes to the reproductive stage, and from March, the first flower primordial could be observed. C. crispa shows similarity with other geophytes in which florogenesis and the development of new organs occurs within the renewal buds during or after the summer dormancy period.Chloraea crispa Lindl. (Orchidaceae) es una orquídea terrestre endémica de Chile, con potencial como nueva alternativa para la industria de flor de corte. Los objetivos de este estudio fueron describir el ciclo fenológico y el desarrollo de yemas florales de C. crispa de manera de determinar el comienzo de la iniciación floral y la diferenciación de la vara floral. Durante el verano las plantas se encontraron en dormición, las yemas de renuevo se localizaron en la parte superior del rizoma, cercanas a las yemas que originaron el crecimiento de la temporada anterior. Desde finales del verano hasta el final del invierno, las plantas se encontraban en crecimiento vegetativo. Desde junio en adelante el tallo floral comenzó a emerger. La floración junto con la senescencia de las hojas ocurrió durante la primavera hasta los comienzos de verano. Las yemas de renuevo comenzaron la formación de primordios foliares, durante o después de la floración de los crecimientos de la temporada y senescencia de la planta. Entre diciembre y enero, el meristemo apical cambió al estado reproductivo y desde marzo en adelante fue posible observar los primeros primordios florales. C. crispa presenta similitudes con otras geófitas, donde la florogénesis y el desarrollo de nuevos órganos ocurre al interior de las yemas de renuevo durante o después del periodo de dormición estival

Vernalisation and photoperiod sensitivity in wheat: the response of floret fertility and grain number is affected by vernalisation status

The impact of different allelic combinations of VERNALIZATION1 (VRN1) and PHOTOPERIOD1 (PPD1) on the development of reproductive structures, spike dry weight (SDW) and its links to the duration of stem elongation (SE) and yield components was assessed using Near Isogenic Lines (NILs) of the cultivar Sunstate for both genes. Emphasis was on observations on the main shoot and tillers, linking to plant and canopy level in Steinfort at al. (2016). Experiments under controlled and irrigated field conditions relevant to the northern wheat growing region of Australia were designed. In vernalised plants, the number of fertile florets in the main shoot spike was positively related to the number of fertile spikelets, the duration of SE, the SDW at anthesis and the sum of the radiation intercepted during SE, while no associations were found under non vernalised and slow vernalising field conditions. Vernalised plants also produced more grains in the average tiller spike, compared to non vernalised plants, particularly under short days. Both main shoot and tiller grain number per spike contributed to the higher grain number per plant observed in vernalised plants in Steinfort et al. (2016), as spike number was similar. In the field, higher yield of lines with spring alleles of VRN1 was underpinned by longer spikes, with fewer spikelets but more fertile florets per spikelet in the main shoot spike, and more grains per tiller. When non vernalised, winter lines had an apex that grew slower, shorter spikes and higher spikelet density compared to the other genotypes. The utilisation of sensitivity to VRN1 or PPD1 to increase the duration of the SE and the number of fertile florets and grains is a more complex process than originally proposed