Determination of the effects of the rebar-cement bond parameters variation in UHPFRC using FA and ANN

The experimental study included the design and production of ultra-high-performance steel fiber-reinforced concrete (UHPFRC). The physical and mechanical properties of UHPFRC were investigated in a laboratory setting. To investigate the properties of UHPFR concrete, three types of concrete and over 70 samples were used. Following that, samples were created to test the anchors' load-bearing performance. Six concrete slabs with a total of 108 pre-installed anchor samples and six concrete slabs with 108 post-installed chemical anchor samples were created. The analysis of the test findings comprised all individual results as well as the definition of the relationship between the anchor's tensile load capacity and other parameters. To accurately determine the individual influence of the investigated factors as well as their combined impact, a factorial experiment, and artificial neural networks were used in addition to normal statistical numerical studies. It was determined that both approaches offer advantages. The results obtained show matches in certain parts. Due to the way data is processed in different ways, there are also significant differences between them

The Chemometric Study of Limestone Physico-chemical Properties and Thermal Behavior for Application in Construction Composites

The limestone, as an economically sustainable and easily available basic raw material, is frequently utilized in the building industry for resolving of the environmental protection issues. The limestone is incorporated in a cementitious system either by grinding with cement clinker, or by blending with the binder during concrete production. The employing of powdery limestone as partial cement replacement gives the construction composites with properties comparable to that of conventional concrete. The study of limestone thermal behavior and its chemistry is crucial for the prognosis of the designed composites properties. In this work, the instrumental techniques (atomic emission spectroscopy, differential thermal and thermo-gravimetric analysis, Fourier transform infrared spectroscopy) and the Principal component analysis were employed to discriminate and classify 22 limestone types. The PCA statistical method, as a means of spectra and experimental data fingerprinting, grouped the samples in a multi-dimensional factor space producing four graphical prognosis - one for each instrumental method. DTA/TG peak values varied the most in a short range between 830-870 degrees C, while FTIR spectra showed the highest diversity in the 867-887 cm(-1) and 1237-1647 cm(-1) ranges. This research was governed by an idea to reveal whether it is possible to differentiate various limestone types and to predict the possibility of their employment in construction composites on the basis of the results of instrumental and mathematical analyses

Prenošenje otpornosti prema Sclerotinia iz divljeg u gajeni suncokret - kombinovanje konvencionalnih i laboratorijskih tehnika

Five populations of each H. molis, H. maximiliani, H. rigidus and H. tuberosus were screened for resistance to stem form of Sclerotinia. On the basis of the results obtained by screening, nine crosses of resistant populations with either other wild species populations or with cultivated sunflower were made. As in some crosses a small quantity of seed was produced and the seeds germinated poorly, modified tissue culture methods were used to enhance germination and produce clones of interesting plants. These methods were found to be efficient both for seed germination and plant production and multiplication.Testirano je po pet populacija H. molis, H. maximiliani, H. rigidus i H. tuberosus na otpornost prema Sclerotinia stabla. Na osnovu dobijenih rezultata izvršeno je devet ukrštanja otpornih populacija sa drugim divljim vrstama ili gajenim suncokretom. Kako je u nekim slučajevima dobijena mala količina semena koja su slabo klijala, korišćene su modifikovane metode kulture tkiva da bi se povećala klijavost i proizveli klonovi interesantnih biljaka. Ove metode su se pokazale efikasnima i za naklijavanje semena i za proizvodnju i umnožavanje biljaka

Impact of lime and NPK fertilizers on yield and quality of oats on pseudogley soil and their valorisation

In order to determine the effect of fertilization, environment, and their interactions on the yield and oats yield components. Five fertilization treatments (T1-control, T2-80 kg N ha-1, T3-120 kg N ha-1, 80 kg P2O5 ha-1 and 80 kg K2O ha-1, T4-N120P80K80 + 5 t ha-1 of lime and T5-N120P80K80 + 5 t ha-1 of lime + 30 t ha-1 of farmyard manure) were examined during three growing seasons in Kraljevo location in Western Serbia. Grain yield (GY), 1000 grain weight (TGW), hectolitre weight (HW), plant height (PH), panicle length (PL), number of grains per panicle (NGP) and protein content (PC) were analysed. The aim of the study was to determine the effect of organic and mineral fertilization and calcification on the yield and oats yield components. On average, for all fertilizer variants, during the three-year trial, the highest yield of oats 3802 kg ha-1 was obtained in the fertilizer variant with the combined application of NPK fertilizers, lime and manure. Positive highly significant correlation, during in the study trial were found between yields with PH, PL and NGP. Negative and highly significant dependencies were found between protein content with GY, PH and NGP. The results of these studies indicate the importance of rational introduction of adequate quantities of fertilization, calcification and humization in order to make oats as profitable as possible in the agro-ecological conditions in Pannonian Environments

Impact of lime and NPK fertilizers on yield and quality of oats on pseudogley soil and their valorisation

In order to determine the effect of fertilization, environment, and their interactions on the yield and oats yield components. Five fertilization treatments (T1-control, T2-80 kg N ha(-1), T3-120 kg N ha(-1), 80 kg P2O5 ha(-1) and 80 kg K2O ha(-1), T4-N120P80K80 + 5 t ha(-1) of lime and T5-N120P80K80 + 5 t ha(-1) of lime + 30 t ha(-1) of farmyard manure) were examined during three growing seasons in Kraljevo location in Western Serbia. Grain yield (GY), 1000 grain weight (TGW), hectolitre weight (HW), plant height (PH), panicle length (PL), number of grains per panicle (NGP) and protein content (PC) were analysed. The aim of the study was to determine the effect of organic and mineral fertilization and calcification on the yield and oats yield components. On average, for all fertilizer variants, during the three-year trial, the highest yield of oats 3802 kg ha(-1) was obtained in the fertilizer variant with the combined application of NPK fertilizers, lime and manure. Positive highly significant correlation, during in the study trial were found between yields with PH, PL and NGP. Negative and highly significant dependencies were found between protein content with GY, PH and NGP. The results of these studies indicate the importance of rational introduction of adequate quantities of fertilization, calcification and humization in order to make oats as profitable as possible in the agro-ecological conditions in Pannonian Environments

Comparison of distributed plasticity approaches for inelastic analyisis of reinforced concrete frames

Following the emergence and establishment of performance-based design as a widely recognized and applied practice, numerous significant advances in computational techniques have been made. Arguably, nonlinear methods of analysis – static or dynamic – provide the most detailed and accurate insight into behavior of the structure which is designed or assessed. While the current codes of practice permit their use, provisions are vague in some aspects, leaving many decisions and assumptions up to the engineer. This paper aims to expand the relatively limited experience with implementation of different distributed plasticity modeling approaches through a case study based on experimental data. Some particulars of the behavior of structural elements made of strain-softening materials, and of their corresponding numerical models, are briefly introduced. Case study is conducted to provide an overview on the procedures for inelastic analysis of reinforced concrete frames through a side-by-side comparison of four alternative approaches for modeling of RC beams and columns with one-dimensional distributed plasticity finite elements with fiber-discretized cross sections. The analyzed structure consists of a reinforced concrete column with a fixed base, which is, under varying axial loads, subjected to monotonic and cyclic lateral displacements applied at its top. Models comprised of force-based elements with different arrangements of integration points, as well as of displacement-based elements, are compared. Advantages, limitations and special considerations which need to be taken into account for each of the approaches are demonstrated through the example. Influence of concrete confinement is studied by analyzing another column with a different arrangement of transverse reinforcement. Global structural response is evaluated by comparison of pushover and cyclic curves for different models. Influence of modeling approach on objectivity of the local response and the corrections which need to be made for certain approaches are showcased by moment-rotation curves of the yielded section at the column base. Considerations and findings presented in the paper, along with other published case studies, can be used for reference when preparing a computational model for inelastic analysis of a reinforced concrete structure

Gene effect, combining ability and heterosis in sunflower morphophysiological traits

Four interspecies populations, originating from three annual (H. debilis, H. praecox, H. deserticola) and one perennial (H. resinosus) wild species, were used to produce 13 new (cms) inbred lines with cytoplasmic male sterility, three Rf restorer lines with good general combining ability used as testers and their F1 hybrids. A two-year trial with three replicates was set up using the line × tester method. The inbred A-lines, Rf-testers and F1 hybrids differed significantly in the mean values for both studied traits. The mode of inheritance for leaf area was dominance and superdominance of the better parent and for plant height it was superdominance of the better parent. Highly significant positive values of general combining ability for both traits were found in inbred lines NS-G-7, NS-G-8, NS-G-9. The greatest highly significant positive specific combining ability value was found in NS-G-6 × RUS-Rf-OL-168 for the total leaf area per plant and in NS-G-6 × RHA-N-49 for plant height. The non-additive gene effect had greater influence on both traits. A significant heterotic effect was found for both traits in relation to the parental average so as in relation to the better parent

The wild sunflowers collection in Novi Sad

Lowered genetic variability in the cultivated sunflower and use of interspecies hybridization in sunflower breeding were the main reasons to establish the wild species collection. Wild species were collected during collecting trips performed jointly by researchers from Novi Sad and Fargo from 1980 to 1991. A total of 917 accessions were gathered. Different numbers of species (1-37) and populations (52-384) were gathered in each trip and wild sunflower habitats were inspected in 6-21 US federal states. Presently there are 21 perennial and 7 annual species in the collection, represented by 447 accessions. The perennial species are grown in quarantine fields (311 accessions) and kept in temporary seed storage at +4° (163 accessions). Annual species are sawn each year and 136 accessions are kept in temporary seed storage. Seed reserves vary from a few seeds to several thousand per accession and all of them were produced in the period between 1998 and 2004. Several problems were encountered in the course of the establishment maintenance and utilization of the collection: 1. Occasional errors in species determination during collection trips were caused by the presence of natural hybrids, heterogeneity of natural populations and differences in ploidy within the same species; 2. The local continental climate caused loss in material due to winterkill and inability of some species to complete the vegetative cycle; 3. Perennial species were difficult to grow because of low seed viability; 4. Low self-fertility or complete selfsterility precluded seed production and renewal of seed reserves; 5. Wild species were difficult to utilize as a source of desirable genes because of their cross incompatibility with cultivated sunflower. The collection of wild sunflower species has mostly been used for development of disease resistant or tolerant genotypes, new cms and Rf genes and for breeding of special-purpose hybrids

Developing thermal insulation cement-based mortars with recycled aggregate in accordance with net zero principles

The performance of thermo-insulation rendering mortars with alternations in ratios of powdered cordierite and talc was examined. The goal was to confirm that recycled kilnware cordierite can be reapplied in the mortar design without significant deterioration in performance in comparison with OPC mortar. Differential thermal analysis was employed for examining thermally induced reactions. The cavitation erosion, in testing sequences ranging from 30 to 120 minutes, was used to assess the compactness of the mortar structure. The physico-mechanical properties of experimental mortars were investigated. The morphologies of the mortar tablets upon cavitation were studied using a scanning electron microscope. It was established that cordierite and talc filler in amounts up to 20% enhance microstructural packing and mechanical strengths due to improved cementation and therefore contribute to cavitation erosion resistance. Higher amounts of talc cause structural degradation and mass loss during cavitation tests. Reducing manufacturing costs, energy consumption, and greenhouse gas emissions are the main objectives of the production of this waste-based construction composite, as the reuse of waste materials can help achieve a number of Sustainable Development Goals