scholarly journals Preliminary Research On Waste Rubber Application In Cement Bound Base Layer

2021 ◽  
Vol 1202 (1) ◽  
pp. 012047
Author(s):  
Matija Zvonarić ◽  
Ivana Barišić ◽  
Tihomir Dokšanović ◽  
Martina Zagvozda
Keyword(s):  
Weather Conditions ◽  
Crumb Rubber ◽  
Base Layer ◽  
Ecological Problem ◽  
Natural Material ◽  
Major Step ◽  
Short Period ◽  
Conventional Material ◽  
Preliminary Research ◽  
Recycled Rubber

Abstract Besides all the positive characteristics of cement bound courses (CBC), it has some detrimental effects on the pavement wearing courses. Due to cement hydration, this mixture is affected by shrinkage. Shrinkage induces cracks in the whole layer which along with weather conditions propagate through asphalt layers in a short period. Also, it’s stiffness negatively affects cracks propagation without providing elastic support for upper layers. As a result, roads are covered with various damages which reduces driving comfort and safety and demand new financial investments. The focus is on reducing the detrimental effect of CBC on the pavement. Nowadays, large quantities of recycled rubber can be found on the market. Wasted rubber is a large ecological problem due to its long decomposition period. On the other hand, by mechanical grinding and separation process, suitable fractions of rubber can be obtained for use in construction. Consequently, the replacement of conventional material by crumb rubber reduces the consumption of natural material and energy for its exploitation. Appropriate amounts and fractions of recycled rubber have the potential to reduce shrinkage and increase the elasticity of CBC. Within this paper, preliminary research results will be presented on the possibilities of crumb rubber implementation in CBC and its effects on mechanical characteristics. By using recycled materials in construction processes we undertake a major step in the sustainable management of natural resources.

scholarly journals Dynamics of the abundance of cuckoo wasps (Hymenoptera, Chrysididae) in the conditions of the altitudinal-belt heterogeneity of the North Caucasus

2021 ◽  
Vol 35 ◽  
pp. 00023
Author(s):  
Nikolay Vinokurov
Keyword(s):  
Population Dynamics ◽  
New Species ◽  
Weather Conditions ◽  
Nature Management ◽  
North Caucasus ◽  
Protection Measures ◽  
Altitudinal Belt ◽  
The North ◽  
Short Period ◽  
First Time

The work provides data on the dynamics of the abundance of 205 taxa from 19 genera: Cleptes, Colpopyga, Elampus, Omalus, Philoctetes, Pseudomalus, Hedychridium, Hedychrum, Holopyga, Chrysidea, Chrysis, Euchroeus, Chrysura, Pseudochrysis, Spinolia, Spinolia, including species rare and new for the fauna of the North Caucasus and Russia. By the nature of the population dynamics, five groups of cuckoo wasps were identified: spring – represented by 7 species from 4 genera; spring-summer – 76 species from 10 genera; summer – 113 species from 16 genera; summer-autumn – 4 species from 2 genera and spring-summer-autumn – 5 species from 3 genus. According to the duration of flight, eurychronous species of cuckoo wasps were identified, which are found throughout the season from spring to autumn; mesochronous – the years of which affect the end of May and summer months and stenochronous – confined to a short period of time. Eurychronic accounted for 2.4%, mesochronous 24.9%, stenochronic 72.7%. The number of generations of cuckoo wasps is related to the dynamics of the number of the host. In the mountains, the peaks of activity shift towards the middle of summer, most species have one peak of activity; due to the frequent changes in weather conditions in the mountains, the phenological characteristics of the cuckoo wasps and their hosts do not coincide in terms with the lowland populations and the periods of activity can be extended in time. Phenological characteristics of rare and new species for the fauna of the North Caucasus and Russia are presented for the first time. The data obtained expand the understanding of the biodiversity and dynamics of the abundance of cuckoo wasps in the North Caucasus and can be used for environmental protection measures and rational nature management in the south of Russia.

scholarly journals Influence of Detasseling Methods on Seed Yield of Some Parent Inbred Lines of Turda Maize Hybrids

Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 729
Author(s):  
Alexandru Bogdan Ghețe ◽  
Voichița Haș ◽  
Roxana Vidican ◽  
Ana Copândean ◽  
Ovidiu Ranta ◽  
...  
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Weather Conditions ◽  
Inbred Lines ◽  
Plant Performance ◽  
Yield Response ◽  
Genetic Purity ◽  
Short Period ◽  
Number Of Leaves ◽  
Hybrid Maize

During the process of maize seed production, in order to ensure the genetic purity of parental forms of hybrid maize, an important work performed is the removal of male inflorescences from plants on mother rows. Hand detasseling has high precision but is labor-intensive. Mechanical detasseling offers the possibility to cover large acreages in a short period of time, but the number of leaves removed has a varying influence on plant performance and seed yield. The aim of this study was to simulate three types of damages on plants similar to those induced through mechanical detasseling and to assess the effects for five inbred lines during the course of three years. Results show that when tassels alone were removed, the average seed yield decreased an average of 4–21%. When two leaves were removed with the tassel, yield decreased an average of 22–31%, while when plants were cut above the main ear, seed yield decreased an average of 31–66%. Environmental conditions influenced seed yield, especially high temperatures during flowering. Yield response to tassel and leaves removal varied between the inbred lines. Genotype controls maize ear and kernel characters, while environmental factors exercise a strong influence on seed yield, due to the succession of years with contrasting weather conditions in a key phenophase. Within the trend of full mechanization in agriculture, identification of inbred lines that cope better with plant damage can assist in optimizing seed production.

scholarly journals Prediction Models for the Mechanical Properties of Self-Compacting Concrete with Recycled Rubber and Silica Fume

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1821 ◽  
Author(s):  
Robert Bušić ◽  
Mirta Benšić ◽  
Ivana Miličević ◽  
Kristina Strukar
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Silica Fume ◽  
Prediction Models ◽  
Crumb Rubber ◽  
Fine Aggregate ◽  
Rubberized Concrete ◽  
Self Compacting Concrete ◽  
Recycled Rubber ◽  
European Standards

The paper aims to investigate the influence of waste tire rubber and silica fume on the fresh and hardened properties of self-compacting concrete (SCC) and to design multivariate regression models for the prediction of the mechanical properties of self-compacting rubberized concrete (SCRC). For this purpose, 21 concrete mixtures were designed. Crumb rubber derived from end-of-life tires (grain size 0.5–3.5 mm) was replaced fine aggregate by 0%, 5%, 10%, 15%, 20%, 25%, and 30% of total aggregate volume. Silica fume was replaced cement by 0%, 5%, and 10% of the total cement mass. The optimal replacement level of both materials was investigated in relation to the values of the fresh properties and mechanical properties of self-compacting concrete. Tests on fresh and hardened self-compacting concrete were performed according to the relevant European standards. Furthermore, models for predicting the values of the compressive strength, modulus of elasticity, and flexural strength of SCRC were designed and verified with the experimental results of 12 other studies. According to the obtained results, mixtures with up to 15% of recycled rubber and 5% of silica fume, with 28 days compressive strength above 30 MPa, were found to be optimal mixtures for the potential future investigation of reinforced self-compacting rubberized concrete structural elements.

Demonstration of high-performance pole pieces made of monocrystalline dysprosium for short-period undulators

2019 ◽  
Vol 26 (4) ◽  
pp. 1220-1225
Author(s):  
Takashi Tanaka ◽  
Akihiro Kagamihata
Keyword(s):  
Magnetic Flux ◽  
Curie Temperature ◽  
Saturation Magnetization ◽  
High Performance ◽  
Permanent Magnets ◽  
Magnetic Performance ◽  
Short Period ◽  
Conventional Material ◽  
Selection Of

Reported here are the results of experiments carried out to demonstrate the magnetic performance of dysprosium (Dy) to enhance the capability of undulators. Tiny pieces of monocrystalline Dy surrounded by permanent magnets (PMs) work as pole pieces (PPs) to concentrate the magnetic flux, when cooled down below the Curie temperature of 85 K. A PP made of Dy is much more attractive than one made of a conventional material, because its saturation magnetization is much higher. Furthermore, it also allows for a more flexible selection of PM material, potentially leading to further enhancement of the performance of short-period undulators. Besides these advantages, practical issues related to using Dy PPs and countermeasures against them are discussed.

Creep feeding and prepartum supplementation effects on growth and fertility of Brahman-cross cattle in the dry tropics

1996 ◽  
Vol 36 (4) ◽  
pp. 389 ◽  
Author(s):  
G Fordyce ◽  
NJ Cooper ◽  
IE Kendall ◽  
BM O'Leary ◽  
Jde Faveri ◽  
...  
Keyword(s):  
Post Partum ◽  
Bos Indicus ◽  
Weather Conditions ◽  
Wet Season ◽  
Short Term ◽  
Research Committee ◽  
Creep Feeding ◽  
Dry Tropics ◽  
Creep Feed ◽  
Short Period

Post-partum anoestrus is a primary contributor to low branding rates in Bos indicus cattle herds in the dry tropics of northern Australia [Entwistle, K. W. (1983). Australian Meat Research Committee Review No. 431. To increase branding rates, it was hypothesised that creep feeding for a short period in mid-late lactation during the latter half of the growing season may trigger an earlier onset of post-partum oestrus cycling, just as short-term, high-level, prepartum supplementation can achieve. Two experiments were conducted using Fn Brahman-cross cows (1/2, 5/8 and 3/4 crosses with Beef Shorthorn) which calved from late October to late Januarv. Cows were mated from mid-late Januarv to mid-April. Calves in one treatment in both experiments had ad libitum access to creep feed (calf pellets: 16% crude protein, 10 MJ ME/kg) for 4042 days from late February to early April. In experiment 2, the effects on cow growth and fertility due to supplementation with either cottonseed meal (1.5 kg/day) or molasses with 7.4% (w/w) urea for 49 days late in the dry season before calving ('spike' feeding) were also evaluated. Control cattle were unsupplemented. Creep feed was only consumed at 0.1 and 0.4 kg/day in experiments 1 and 2, respectively. Short-term creep feeding had no consistent effects on cow liveweights, condition, or fertility, or on calf growth and temperaments under extensive grazing conditions during the tropical wet season. Spike feeding reduced weight loss by 0.2-0.4 kg/day (P<0.01). The effects on liveweights did not persist into the wet season. There were no effects on cow fertility in this year of extreme weather conditions, when 4 months of nutritional and climatic stress followed supplementation.

scholarly journals Lipid Nanocarriers for Anti-HIV Therapeutics: A Focus on Physicochemical Properties and Biotechnological Advances

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1294
Author(s):  
Maria J. Faria ◽  
Carla M. Lopes ◽  
José das Neves ◽  
Marlene Lúcio
Keyword(s):  
Physicochemical Properties ◽  
Treatment Options ◽  
Survival Rates ◽  
Aqueous Solubility ◽  
Hiv Infections ◽  
Viral Reservoirs ◽  
Major Step ◽  
Therapeutic Outcomes ◽  
Short Period ◽  
Lipid Nanocarriers

Since HIV was first identified, and in a relatively short period of time, AIDS has become one of the most devastating infectious diseases of the 21st century. Classical antiretroviral therapies were a major step forward in disease treatment options, significantly improving the survival rates of HIV-infected individuals. Even though these therapies have greatly improved HIV clinical outcomes, antiretrovirals (ARV) feature biopharmaceutic and pharmacokinetic problems such as poor aqueous solubility, short half-life, and poor penetration into HIV reservoir sites, which contribute to the suboptimal efficacy of these regimens. To overcome some of these issues, novel nanotechnology-based strategies for ARV delivery towards HIV viral reservoirs have been proposed. The current review is focused on the benefits of using lipid-based nanocarriers for tuning the physicochemical properties of ARV to overcome biological barriers upon administration. Furthermore, a correlation between these properties and the potential therapeutic outcomes has been established. Biotechnological advancements using lipid nanocarriers for RNA interference (RNAi) delivery for the treatment of HIV infections were also discussed.

scholarly journals When it rains in the desert of Patagonia: heavy rains, sediment laden flash floods and hazard management challenges.

2021 ◽  
Author(s):  
Gabriel Kaless ◽  
Héctor Malnero ◽  
Oscar Frumeto ◽  
Miguel Pascual
Keyword(s):  
Weather Conditions ◽  
Flash Floods ◽  
Ephemeral Streams ◽  
Hazard Management ◽  
Mean Values ◽  
Short Period ◽  
Maximum Water ◽  
Water Stage ◽  
Rainfall Flood ◽  
Combined Data

Ephemeral streams in dry environments can produce high intensity sediment-laden flash floods. The research of these events is quite difficult due to far locations with limited accessibility, unexpected events, and rough weather conditions. Hence combined data of rainfall, flood hydrograph and sediment transport is rather scarce in the world. Recent extreme events (RI > 550 years) in arroyos (ephemeral streams) of the central Patagonia (Argentina) has called the attention of public and scientific community. The Sagmata basin (total drained area of 129 km2), located in the Lower Valley of the Chubut River (Province of Chubut, Argentina) has been equipped with 4 raingauges, a weather station, four cameras and sediment sampler in four reaches of the arroyos. Data from a two-year monitoring provides valuable insights about the hydrological response of basins in Patagonia, such as the time of response, the shape of hydrographs and its relations with the hyetographs and duration curves. The arroyos are wetted a short period of the time (8 to 21 hours a year). Single-peak, multi-peak and flat top hydrographs have been observed. The lag-time decreases with the increase of the rainfall intensity and the maximum water stage. Moreover, the bore front moves with mean speed which value is between 0.8 to 1.6 m s-1. The wash load in the arroyos depends on geological settings and vegetation cover of the basin. Mean values are between 23 – 46 gr l-1. The complex hydrograph shape produced by the basin has been linked to the rainfall features (duration, mean intensity and patchiness) and the basin physiography of the basin. Findings from the present study provide valuable information both for the comprehension of arroyos in drylands and hazard management as well.

scholarly journals Visualizations of the Doblar Accumulation Basin Based on the UAV Survey

2019 ◽  
Vol 1 ◽  
pp. 1-7
Author(s):  
Klemen Kozmus Trajkovski ◽  
Gašper Štebe ◽  
Dušan Petrovič
Keyword(s):  
3D Model ◽  
Weather Conditions ◽  
Point Clouds ◽  
Water Levels ◽  
Contour Lines ◽  
Digital Elevation ◽  
Short Period ◽  
Dense Point ◽  
Aerial Vehicle ◽  
Elevation Model

<p><strong>Abstract.</strong> Our research is based on a large case study of Unmanned Aerial Vehicle (UAV) surveys, modelling and visualizations of the Doblar accumulation basin. The various approaches for UAV surveying of large, demanding terrain configurations, and the benefits of surveying products used as a basis for other interdisciplinary hydrological and environmental services were researched. The demanding mountainous terrain, the steep slopes and deep and narrow streams required detailed pre-planning of the survey, including the pre-survey terrain overview. The accumulation basin was emptied merely for a short period; thus, the survey was performed in unfavourable weather conditions, which included coldness, snowfall and wind. Point clouds were generated and georeferenced from the 4377 recorded photos. The dense point cloud contained approximately 222 million points in the medium setting and more than a billion in the high setting. A 3D model was built from the data. This became the basis for numerous further analyses and for the presentation using cartographic principles: a digital elevation model with a resolution of 10&amp;thinsp;cm, an orthophoto with a resolution of 10&amp;thinsp;cm, a 3D model draped with orthophoto, contour lines with a 1&amp;thinsp;m interval, topographic profiles, calculations of volumes at different water levels, a flythrough, augmented reality and a video simulation of the water level changes. The model can also serve as a basis for hydraulic and environmental analysis and simulations or used for analyses of the accumulation and deposition of river material compared with previous and future surveys.</p>

scholarly journals ADVANCED CHARACTERIZATION OF RECYCLED RUBBER FROM END-OF-LIFE TIRES

2020 ◽  
Vol 93 (4) ◽  
pp. 683-703
Author(s):  
J. L. Valentín ◽  
R. Pérez-Aparicio ◽  
A. Fernandez-Torres ◽  
P. Posadas ◽  
R. Herrero ◽  
...  
Keyword(s):  
End Of Life ◽  
Experimental Approach ◽  
New Technologies ◽  
Advanced Characterization ◽  
Crumb Rubber ◽  
Added Value ◽  
Double Quantum ◽  
Characterization Methods ◽  
Recycled Rubber

ABSTRACT There are currently many well-established applications for recycled rubber from end-of-life tires (ELT), but it is essential to investigate and seek new approaches to enhance the value of these products. Recent developments in new technologies and innovative recycling and devulcanization processes have opened up new perspectives for ELT crumb rubber. To promote the use of these products in newly added value applications, it is essential to develop and optimize methods that allow the characterization of parameters related to the ultimate properties of potential final applications. In this respect, a novel characterization methodology based on advanced 1H double-quantum (DQ) nuclear magnetic resonance experiments has been applied for the first time to quantify the key parameters that characterize the structure of ELT crumb rubber after diverse recycling processes: from simple mechanical grinding to complex devulcanization methods. This experimental approach enables the quantification of parameters that define the network structure of rubber, such as the nonelastic network defects (sol fraction, dangling chain ends, loops), the cross-link density, and the heterogeneity of the network, directly from rubber granulate and powder (without any additional sample preparation steps), overcoming most of the drawbacks and uncertainties that limit the application of traditional rubber characterization methods (e.g., equilibrium swelling experiments). By applying this experimental approach, it is possible to identify and quantify the actual technical limits for a complete selective devulcanization process of ELT crumb rubber.

scholarly journals Modification of the mechanical properties of rubbers by introducing recycled rubber into the original mixture

2013 ◽  
Vol 12 (4) ◽  
pp. 352-358
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Experimental Work ◽  
Crumb Rubber ◽  
Mechanical Stresses ◽  
Rubber Composites ◽  
Original Mixture ◽  
Tensile Fatigue ◽  
Recycled Rubber ◽  
The One

In our experimental work the opportunities of improving of mechanical properties of rubbers and their composites have been investigated. On the one hand the reuse of milling product of recycled rubbers (recycled crumb rubbers) has been studied and the effects of the filler and compatibilizers applicable in rubber composites on the mechanical properties either. The rubber composites were exposed to different mechanical stresses (tensile, fatigue tensile) and Shore A hardness and density of the specimens have also been determined. Morphology of the composites and the interaction between the fillers and the rubber has been studied on SEM graphs. Recycled crumb rubber was added in different concentrations to the basic mixture of rubber. Significant improvement of mechanical properties could be achieved by mixing 22m/m% used crumb rubber to the basic mixture. Tensile strength at break of composites containing recycled crumb rubber increased with nearly 20% compared to the original basic mixture containing no crumb rubber. Density decreased with 2-3% and Shore A hardness with 6% comparing the aforementioned composites. Different types of compatibilizing additives have also been applied in the system containing crumb rubber which showed different effectiveness in case of the properties, e.g. tensile strength at break. Adding compatibilizing additives to the basic mixture of rubber did not make the density changed while Shore A hardness changed similarly to the trend observed in case of tensile strength at break.

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