2,085 research outputs found
Investigation into the ductile and damping behaviour of concrete incorporating waste tyre rubber
University of Technology, Sydney. Faculty of Engineering and Information Technology.Sustainable development has grown to be a major concern to the construction industry with the main effort and attention in recent times devoted to developing innovative solutions to preserve the environment and natural resources. One suggested approach in aiding the conservation of natural resources is to recycle waste material for innovative use in construction applications.
This thesis reports on the fundamental findings of an investigation into an elastomeric modified concrete (EMC), in particular its ductile and damping performance. This first- of-its-kind-in-Australia EMC incorporates Styrene Butadiene Rubber (SBR) waste tyre granules as a partial replacement of fine and coarse aggregates.
Another significant feature of this project is that until now 100% Portland cement plain concrete has been utilised to evaluate the mechanical performance of EMC reported in literature, however, in this study the use of a supplementary cementitious material, that of fly ash (FA), is suggested as a partial replacement of Portland cement to create a more environmentally friendly construction material. Moreover, in order to examine the improvement of adhesion properties between the SBR granules and the cementing matrix, a styrene butadiene (SB) copolymer emulsion has been introduced to the couple of mixes.
In the first experimental work stage two sets of EMC were prepared; one with small SBR granules (1 to 4 millimetres) in proportions of 5%, 10% and 15% of the total weight of aggregates; the other with larger SBR granules (12 to 15 millimetres) in proportions of 2%, 4%, 6% and 10% of the total weight of aggregates. In order to evaluate the damping and ductility properties of concrete, several tests were conducted following Australian Standards (AS) and American Society for Testing and Materials (ASTM), including compressive strength, static chord modulus of elasticity, modulus of rupture and dynamic modulus of elasticity.
Compared to the control concrete, EMCs demonstrated lower density (mass per unit volume) and higher air content with increasing additions of SBR granules to EMCs. Furthermore, the compressive strength was found to decrease with increasing additions of SBR granules to EMCs. In contrast, static chord modulus of elasticity (MOE) and modulus of rupture (MOR) of EMCs were found to increase compared to the control concrete. Unlike the control concrete, EMCs did not exhibit a brittle-like failure.
In the second experimental work stage, five reinforced beams (two for four point bending and three for three point bending tests) were made based on Australian standards. There were two sets of tests conducted on beams: destructive and non-destructive. Four point bending and three point bending tests were used to investigate the static properties of beams. To evaluate dynamic properties, hammer test was carried out prior to initiation of loading and also after failure of beam in four point bending test. The stiffness and maximum load of the beams decreased with the addition of SBR granules, however, the damping ratio of the beams increased. The project also included simulation and modelling of static tests using analysis by computer programs.
This study encompassed a large experimental component and through specific testing, the best performing materials is selected to achieve the highest damping-to-ductility ratio
Pathway towards carbon neutrality by 2035 within the context of sustainable energy production, case study:Oulun Energia Group
Abstract. Climate change is a phenomenon that has been caused by the disturbance in Earth’s energy and carbon cycle. Energy production via burning fuels, especially fossil fuels is one of the dominant players that disturbs these cycles. Both energy and climate are included in sustainable development goals. Carbon footprint is a way to assess the impact of a product or a service on climate change. The result of the calculation is a useful tool in strategic planning related to climate change initiatives and carbon neutrality. In this study, the main target was to calculate the carbon footprint of the case study (Oulun Energia Group). Oulun Energia Group is a local energy company based in City of Oulu, Finland. It is the company’s target to be carbon neutral by 2035. There are several methodologies for science-based carbon footprint calculation. The method for this study is based on the GHG Protocol Standard. The first practical step was developing a roadmap based on the standard. Calculation started with Scope 1 emissions for Oulun Energia Oy, for the years 2020 and 2021. The result for the year 2020 is 507739.26 tonne CO₂eq and for the year 2021 is 412385.11 tonne CO₂eq. The value-added of the work for the company is a science-based approach towards the carbon neutrality goal by calculating the carbon footprint
Double Relaxation via AdS/CFT
We exploit the AdS/CFT correspondence to investigate thermalization in an N=2
strongly coupled gauge theory including massless fundamental matter (quark).
More precisely, we consider the response of a zero temperature state of the
gauge theory under variation of an external electric field leading to a
time-dependent current. The holographic dual of the above set-up is given by
introducing a time-dependent electric field on the probe D7-brane embedded in
an AdS_5 X S^5 background. In the dual gravity theory, due to a time-dependent
electric field an apparent horizon forms on the brane which, according to
AdS/CFT dictionary, is the counterpart of the thermalization process in the
gauge theory. We classify different functions for time-dependent electric field
and study their effect on the apparent horizon formation. In the case of pulse
functions where the electric field varies from zero to zero, apart from
non-equilibrium phase, we observe that two apparent horizons form on the brane.
On the gauge theory side, it means that the state of the gauge theory
experiences two different temperatures during the time evolution.Comment: 28 pages, 13 figures, published versio
Effects of Drought Stress on Photosynthesis Factors in Wheat Genotypes during Anthesis
Drought is one of most important environmental factors inhibiting photosynthesis and decreasing growth and productivity of plants. The sensitivity of crop plants such as wheat to soil drought is particularly serious during reproductive phase is extremely sensitive to plant water status. The aim of this work was to study the effects of drought stress on photosynthesis, photosynthetic pigments, soluble proteins, a-tocopherol and abscisic acid content in six wheat genotypes, two tolerant (Daric and 92 Zhong), two moderately tolerant (Sabalan and DH-2049-3) and two sensitive (Shark and Tevee’s’). Total chlorophyll content, relative water content and chlorophyll a/b ratio decreased after long-time drought stress, that decrease in sensitive genotypes was higher than others. Net photosynthesis and stomatal conductance decreased significantly (P < 0.05) in flag leaves of our genotypes under drought stress after pollination, that decrease in sensitive genotypes was higher, too. Abscisic acid content, soluble protein content and a-tocopherol increased under drought stress, that increase in tolerant genotypes was higher. There was a significant negative correlation (P < 0.05) between photosynthesis factors and abscisic acid content in flag leaves of all genotypes. It can be concluded that Daric and 92 Zhong had a better photosynthesis factors compared to other genotypes and showed a higher capacity to tolerate drought stress
Two Wrongs Don\u27t Make a Right: Federal Death Eligibility Determinations and Judicial Trifurcations
Broadly speaking, the purpose of this article is to bring attention to this radical and irreconcilable disparity between the unequivocal Sixth Amendment right of confrontation criminal defendants are afforded at trial,and the limited, qualified right of confrontation the FDPA grants federal capital defendants during death-eligibility determinations, which occur as part of the sentencing phase. It advances the argument that there is no tenable principled distinction on which this disparate procedural treatment may rest. We will attempt to demonstrate that, as written, the statutory provision that governs the admission of evidence at capital sentencings—18 U.S.C. § 3593(c)—is unconstitutional on its face as it applies to death eligibility determinations—and cannot be salvaged by judicial construction...In reaching our conclusion, this article will explore, inter alia, the extensions of our constitutionally grounded right of confrontation; that is, “[i]n all criminal prosecutions” the Confrontation Clause of the Sixth Amendment unequivocally grants the accused the right “to be confronted with the witnesses against him.”...In Part I, we will attempt to frame the problem we believe needs to be addressed: the manner in which the relaxed evidentiary standard 18 U.S.C. § 3593(c) prescribes deprives capital defendants of the full panoply of their Sixth Amendment confrontation rights during the litigation of facts that are the functional equivalent of elements of federal capital murder, inter alia, by allowing the trial judge to admit testimonial hearsay at his or her discretion. In Part II, we will explore the Supreme Court’s recent forays into what we shall call, for the purpose of this article, “functional equivalence jurisprudence,” to illustrate the constitutional significance of equating statutorily prescribed aggravating factors with elements of an offense, and its resonation with some federal district courts. In Part III, we will advance an alternative argument for applying the right of confrontation to the eligibility determination based on a careful reading of the text of the Sixth Amendment. In Part IV, we will sketch the history of the Sixth Amendment right of confrontation and explore the manner in which the Court’s holding in Crawford marked a sea change in its Sixth Amendment jurisprudence. In Part V, we will turn to Crawford’s effect on 18 U.S.C. § 3593(c).In Part VI, we will explore the recent phenomenon of judicially imposed trifurcation in an effort to address the FDPA’s constitutional shortcomings, and we will argue that that practice, whether by motion or sua sponte, is likewise unconstitutional. Finally, in Part VII, we will propose a pragmatic solution to this constitutional quandary: legislatively mandated trifurcation
Agar alternatives for micropropagation of African violet (Saintpaulia ionantha)
Agar is one of the most popular solidifying agents in plant tissue culture. High price of pure grade agar and fear of over exploitation of its resources caused searching for low cost alternatives. In this study,liquid medium with cotton substratum and different combinations of starch, semolina, potato powder and agar in two steps of micropropagation (shoot induction and proliferation) were investigated. The highest frequency of regeneration was found in media containing agar (0.8%), combination of starch: semolina: potato powder (2:1:1) in 9 and 12% and combination of starch (6%) plus agar (0.4%), butmaximum shoot numbers were produced in media containing agar (0.8%), combination of starch (6%) plus agar (0.4%) and liquid medium with cotton substratum. The best shoot proliferation take place in liquid medium with cotton substratum. The results show that the combination of starch: semolina: potato powder (2:1:1) in 9% and starch (6%) plus agar (0.4 %) can be suitable alternatives for agar in regeneration stage but the shoot number is lower than agar alone. These options are very cheaper than agar. The best shoot proliferation can be done in bioreactors or liquid medium with suitable substratum like cotton.Keywords: Gelling agent, low cost, micropropagation, liquid cultur
Cultural competence in nursing: A concept analysis
Background: Cultural competence is one of the principal foundations of clinical nursing. It has not yet been clearly defined and analysed and there are different views regarding this issue. Objective: Analyzing the concept of cultural competence in nursing. Design: A concept analysis. Data Sources: The literature was searched using electronic databases including PubMed, ScienceDirect, Scopus, ProQuest, Google Scholar, CINAHL, Wiley, Ovid, Magiran, and SID with no date limitation. Any quantitative or qualitative studies published in English or Persian, which were focused on cultural competence in nursing were included in the study. Review methods: Walker and Avant's strategy for concept analysis was used. The attributes, antecedents, consequences, and uses of the concept were identified. Results: A total of 43 articles were included. The six defining attributes of cultural competence were cultural awareness, cultural knowledge, cultural sensitivity, cultural skill, cultural proficiency, and dynamicity. Antecedents included cultural diversity, cultural encounter and interaction, cultural desire, cultural humility, general humanistic competencies, educational preparation, and organizational support. The consequences of cultural competence were also identified: those related to care receivers, those related to care providers, and health-related consequences. Conclusion: A theoretical definition and a conceptual model of cultural competence were developed. The attributes, antecedents, and consequences of cultural competence identified in this study can be used in nursing education, research, and managerial and organizational planning. © 201
Effect of genotypes and culture medium on shoot regeneration and proliferation of Gerbera jamesonii
Gerbera jamesonii is one of the most popular cut flowers in the world and micropropagation is the commercial way for its propagation. This method allows for obtaining large amounts of healthy homogenous plants. Thus, it is necessary to establish efficient micropropagation protocols. The objective of this study was to evaluate the organogenic response of G. jamesonii, orange and pink cultivars, under in vitro culture. Different levels of N6-benzyladenine (BA) (2, 4 and 6 mg/l) and thidiazuron (TDZ) (0.2, 0.4 and 0.6 mg/l) in combination with Indole-3-acetic acid (IAA) (0 and 0.1 mg/l) in MS medium were evaluated for shoot induction. For proliferation, regenerated shoots in TDZ were subcultured in medium supplemented with 0.2, 0.4 and 0.6 mg/l TDZ, 2 mg/l BA or 2 mg/l Kin and regenerated shoots in BA were subcultured on the induction medium. In the second phase, mediums of MS, 1/2 MS, MS with 1/2 NH4NO3 and KNO3 concentration (MS-1/2N), MS with 1/2 micro and iron elements (MS-1/2MI), B5 and 1/2 B5 on shoot induction and proliferation of pink cultivar were evaluated. In order to induce rooting in the regenerated shoots, different levels of IAA (1, 2 and 3 mg/l) and 1-Naphthaleneacetic acid (NAA) (1, 2 and 3 mg/l) in combination with sucrose (30 and 40 g/l) were evaluated Maximum shoot induction, (88.8 % and 44.4 % for orange and pink cultivars, respectively) and multiplication rate (7.6 shoots/explant for orange cultivar and 1.33 shoots/explant for pink cultivar) were obtained in medium with 4 mg/l BA and 0.1 mg/l IAA. The most effective media for shoot induction and proliferation were MS-1/2N and MS, respectively. The best rate of shoot rooting in orange cultivar (4.6 roots/explants with 4.8 cm length) and pink cultivar (5.2 roots/explants with 6.2 cm length) was obtained by using 3 mg/l IAA and 30 mg/l sucrose. The establishment of plantlets was done successfully with 92% of survival in the greenhouse.Key words: Micropropagation, organogenesis, in vitro culture, Gerbera, cut flower
Effect of the solvent quadrupolarizability on the strength of the hydrogen bond: Theory vs data for the Gibbs energy and enthalpy of homo- and heteroassociation between carboxylic acids and water.
A cavity model of the effect of a solvent on thermodynamic parameters of dimerization of polar species in non-polar liquids has been developed and compared to experimental data. Bulk solution data have been collected for stearic acid in cyclohexane and in toluene to quantify the extent of self-association of the acid in terms of the dimer self-dissociation constant, Kd. Composition and temperature-dependent experimental data have been collected to determine Kd, the enthalpy of dissociation, and temperature-dependent infrared molar absorption coefficients. The interaction of stearic acid with small amounts of water present in non-aqueous solvents is also addressed and quantified with a hetero-dissociation (or dehydration) constant, Kh. Existing data for acetic acid are also considered. The model connects Kd and Kh to the vapor-phase association equilibria. Solute dipole-solvent quadrupole interactions are shown to have a major effect on Kd in quadrupolar liquids, such as toluene, benzene, and CS2. This work provides important background as a prelude to adsorption studies of these additives from non-aqueous solvents to solid surfaces with relevance to commercial fluids, such as oil-based corrosion inhibitors and friction modifiers. Moreover, the presented theory of the solvent effect on Kd is a first step to generalization of standard implicit solvent models in computational chemistry (such as the polarizable continuum model) to media of significant quadrupolar strength. This is expected to be particularly important for polar species dissolved in CO2 relevant for carbon capture and storage where appropriate models do not currently exist
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