Portal de Revistas Académicas UC Temuco
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Vegetation Cover Composition and Seed Bank Study of Beach Sand Dunes in Karkurah Coastal Area, east of Libya
Get PDFAbstractThe present work was carried out in the coastal sand dunes along the beach of Karkurah area, about 100 km south west of Benghazi, during (January to August 2008), in order to study the relationships between vegetation and environmental factors. Vegetation and soil were sampled in 40 quadrats representing the physiographic variation and different habitat types in the study area. The chemical and physical characteristics of soils were determined for 8 samples and there were significant differences in soil variables like pH, Mg, Na, k, soil texture. Density, constancy and mean cover for each 26 perennial species were calculated. 75 plant species identified, belonging to 34 families, and 68 genera, and deposited at Botany department herbarium, Faculty of science, University of Benghazi. The constancy of perennial species showed the dominance for Retama raetam, Nitraria retusa, Ammophila australis, Lycium schweinfurtii, Ononis natrix. The life form determined, and the most common Therophytes constituted (48%), Chamaephytes (29.3%), Phanerophytes (13.3%) and Cryptophytes (9.3%). Species richness was calculated as average number of species per number of quadrats, and the value was (1733/40) = (43.3), The Simpson index value was (0.85). Total number of seeds in all quadrats was (5536 seeds/m²), the highest number was (323 seeds/m²) in the quadrat which was located on stabilized sand dunes, while the lowest number of seeds was (53 seeds/m²) quadrat was located on dunes facing the sea. The enhanced anthropogenic pressure was in form of quarrying activities , collection of medicinal plants, agriculture, and over grazing are imposing a serious threat to the diversity in the area in the near future
Proximate, mineral and pytochemical screening of ethanolic leaf extract of Senna occidentalis as phytobiotic additive in poultry rations.
Get PDFThe proximate, mineral and phytochemical components of Senna occidentalis leaves ethanolic extract were determined in triplicates using standard laboratory procedures. The results of the proximate analyses revealed that Senna occidentalis leaves ethanolic extract had 8.40% moisture content (MC), 20.49% crude protein (CP), 18.31% crude fibre (CF), 27.36% ether extract (EE), 9.20% ash, 16.24% nitrogen free extract (NFE) and 3550.81 Kcal/kg metabolizable energy (ME). It was observed that the leaves contained 190.80, 28.20, 1930.00, 18.00, 7.15, 8.26, 4.30 and 8.66mg/l of potassium (K), sodium (Na), calcium (Ca), magnesium (Mg), manganese (Mn), iron (Fe), copper (Cu) and zinc (Zn) respectively. The phytochemical screening showed that cardiac glycosides and phenols were absent, flavols were present, while saponins, favonols and alkaloids were largely present. The analyses revealed that Senna occidentalis leaves ethanolic extract has a potent nutritional and phytobiotic attributes in poultry feeding.Key Words: Coffee weed, minerals, proximate, phytochemicals, phytobiotics.
The Covid-19 Lockdown and Its Impact on the Agri-Food Supply Chain in India: Insights from Government Policy Perspective
Get PDFThe outbreak of the Covid-19 pandemic is an unprecedented shock to the Indian economy. Agriculture being the backbone of the Indian economy has been severely affected by the shock waves of the Covid-19 pandemic and subsequent lockdown. In this paper, we have assessed the potential impact of the shock on Indian agriculture considering their implications along the different stages of supply chain, namely, production, post-harvest handling & storage, processing & packaging, distribution and consumption. In addition, we have analyzed the policies announced by the government in mitigating the impact of the shock and revitalizing the Indian agriculture. Finally, we have put forward some policy recommendations for future consideration
A review on effects of ceramic tile waste as partial replacement of coarse aggregate on geopolymer paver block
Get PDFPaver blocks are used in many areas like street road and other construction places. Due to rapid infrastructure development the use of cement is increasing. Cement emits large amount of carbon dioxide (CO2) and this leads to global warming. Today researches on waste management lead to an eco-friendly product called geopolymer mortar and concrete. To support the development of pavement construction in the civil engineering industry, a new approach to predicting the performance of the geopolymer paver block (GPB) has been proposed. A huge quantity of ceramic waste is generated during processing, transportation and handling. To reduce this waste disposal, ceramic waste can be used as an alternative material to natural coarse aggregate. Fly ash and Ground Granulated Blast-furnace Slag (GGBS) are activated using alkaline solution such as sodium silicate and sodium hydroxide to get cementitious binder. There are various paper and research works based on natural coarse aggregate replaced by various percentages of other industrial waste material and cement replaced by various percentage of other waste material and it is found that there is increase in strength, durability and reduction in cost and utilization of waste material. Various waste material can be used for improving strength of paver block. The primary objective of this review is to understand the properties as well as economical and environmental benefits of GPB using ceramic tile waste corresponding to M40 grade (16M) based on earlier researches. From the mix designed, 25% Fly ash and 75% GGBS shows optimum mix. The review work also focus on selection of various percentages of ceramic tile waste for replacing natural coarse aggregate.
Key Words: Geopolymer Paver Block, Fly Ash, GGBS, Cementitious binder, Alkaline solution, Ceramic tile wast
Impact of dust on health of on-site construction workers – a case study
Get PDFThe rate of air pollution is becoming a cause for worldwide concern because of its substantial increase. Different sources like combustion of fuels, release of smoke from industries etc are responsible for the pollution of air. The construction industry is a major contributor to air pollution in the form of dust. Most of the activities involved in the completion of a construction project contribute to the generation of dust in one way or another. There are many sources of dust in a construction site like the use of construction equipment, transportation activities etc. the dust thus generated can ill effects as well. But, the problem of dust pollution is not addressed properly mainly because of the lack of awareness in this area. Proper identification of sources of dust in sites, its health impacts etc can help generate awareness and also help in implementing control measures. This can help reduce dust pollution on site. Here, a residential building site is taken for the case study. A questionnaire survey is conducted for the workers to identify the negative impacts construction dust has and also to determine the most common dust control measures employed in site.
Keywords—air pollution, construction activities, construction equipment, questionnaire survey, dust contro
Material flow in construction sites – a case study
Get PDFThe efficient movement of materials at sites in fair quantity at fair time without any interruption is called material flow. Operation and flow of these materials is a challenge experienced in sites today due to material scarcity, delivery delays, inadequate transportation facilities, loss and wastage, insufficient storage space etc. Data on material flows and inventory levels is intended to promote circular economy and resource efficiency in the construction sector. This paper presents a case study in Kerala, India with the purpose to quantify the flow of materials and stocks in the construction site. A questionnaire survey was conducted to find out the main factors that can affect the flow of materials in the building industry. Out of 65 respondents labour, equipment, material, time and cost are identified as the main factors which can contribute towards material flow. Based on the identified parameters, a material flow pathway is developed for the case study. It demonstrates the management of logistics and factors influencing the movement of materials on work sites. It therefore helps in the analysis of factors concerning the efficient use of materials in infrastructure projects.
Keywords-material flow, logistics management, material scarcity, infrastructure projects
Durability of geopolymer concrete exposed to acidic environment – a review
Get PDFAcids attack concrete by dissolving both hydrated and unhydrated cement compounds as well as calcareous aggregates and the subsequent chemical reaction forms water soluble calcium compounds which are then leached away. The aggressiveness of the reaction depends on the pH of the acidic medium and the types of salts formed. Concrete pipes made of ordinary portland cement (OPC) carrying sewage water have always the presence acidic solutions in it. They deteriorate and service life of the pipes is affected along with the increased maintenance costs and that process cause environmental impacts. Geopolymer binders are novel binders that relies on alumina silicate rather calcium silicate bonds for structural integrity so they have been reported as being acid resistant. Those could be produced by the chemical action between alumino-silicate material such as fly ash(FA), granulated blast furnaces slag (GGBS), metakaoline or silica fume with alkaline solutions like sodium silicate or sodium hydroxide. Geopolymers show superior performance in terms of corrosion and fire resistance due to the absence of water and calcium in their structure.Utilisation of waste materials like FA and GGBS makes geopolymer concrete (GPC) an environment friendly construction material. This review paper looks in to the effect of various acids such as sulphuric acid, acetic acid, nitric acids on durability properties of OPC specimens, GPC specimens and GPC composite specimens when immersed in acidic solutions for certain period. The performance of geopolymer is analysed by the visual inspection and studying the parameters like weight loss, loss in compressive strength and maximum depth of penetration.
Keywords- Geopolymer concrete, Sodium hydroxide, sodium silicate, metakaoline, silica fume, alumina silicat
Effect of glass thickness on performance of double slope inward solar desalination still for fresh water production
Get PDFThis paper deals with the effect of thickness of glass material which covered on double slope solar desalination still, performance of the solar still affected by thickness of the glass, which result in to major heat losses in the system. Two inward double slope desalination still with different glass thickness were designed, constructed and experimentally tested their performance. The glasses are inclined 200 from the center of the still. The solar energy collecting area of still is 1m2.The result shows that the variation in glass thickness will affect the efficiency of the still, desalination still with 4mm thickness gives 48% higher fresh water productivity compare to 6mm glass thickness
Researching of properties of expanded clay concrete on cement-ash binder.
Get PDFUkraine is a state with a powerful industrial base,the waste of which is ash. The use of ash as a binder for the production of expanded clay concrete solves the problem of its disposal. Studies of expanded clay concrete on carbonates and and cement-ash binder were carried out.The research results showed that it is possible to manufacture building structures from this material, including load-bearing ones. Experiments have confirmed the effectiveness of using a cement-ash binder [Vilkov, 1984]. The article provides recommendations on the technology of production of expanded clay concrete mixture and determination of optimal composition. Were made and tested samples of expanded clay concrete on a cement-ash binder with varying degrees of reinforcement with dimensions of 100x150x1200mm. The bearing capacity, crack resistance and deformability of expanded clay concrete were determined by testing on hydraulic press. The compressive strength of the studied expanded clay concrete was tested by loading samples with dimensions of 10x10x10cm and 10x10x40cm. The perspectives of using expanded clay concrete on a cement- ash binder are analyzed.
Keywords: expanded clay concrete, industrial waste, binding material, ash, carbonate send, strength, deflection, deformation, building construction
Thermal efficiency analysis of buildings with phase change materials.
Get PDFIncreasing global temperature is alarming the need for construction industry to have thermally efficient building materials. Incorporating Phase Change Materials (PCM) in buildings is widely accepted method for reduction in temperature, thereby achieving better thermal efficiency. This paper focuses on the assessment of thermal performance of PCM-incorporated building under tropical climatic condition. The simulation process was carried out using Design Builder Software and the developed building model is validated with the results available in the literature. A parametric study is also performed in order to identify the effect of different parameters like building orientation, window to wall ratio, ceiling height and construction material on the indoor air temperature. The results showed that the maximum reduction was up to 2.76°C.
Keywords- Thermal Efficiency, Tropical climate, PC