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Open access

Pyotr Kovalenko, Anatoliy Rokochinskiy, Jerzy Jeznach, Roman Koptyuk, Pavlo Volk, Nataliіa Prykhodko and Ruslan Tykhenko

Abstract

The analysis of the current state of weather and climatic conditions and evaluation of their predicted changes for immediate and distant prospect in the drained areas of Ukrainian Polissia region was carried out in the article. The main trends in changes of meteorological characteristics and their possible effect on the conditions of functioning water management and ameliorative objects and complexes as well as on the natural and ameliorative state of drained areas were identified. The research uses a method of predictive-simulation modelling with used predictive assessment models of normalized distribution of the basic meteorological characteristics in the long-term and one-year vegetation context. According to the results of the research it was established that, for today a high variability in meteorological characteristics can lead to the significant deterioration of operation conditions of water management and ameliorative objects and units, as well as natural and ameliorative conditions of drained lands in Polissia region as a whole. Core measures regarding the adaptive potential enhancement and development in the region under the conditions of climate change were examined.

Open access

Magdalena Domańska, Anna Boral, Kamila Hamal, Magdalena Kuśnierz, Janusz Łomotowski and Paulina Płaza-Ożóg

Abstract

The increasingly stringent requirements for wastewater treatment enforce the adoption of technologies that reduce pollution and minimize waste production. By combining the typical activated sludge process with membrane filtration, biological membrane reactors (MBR) offer great technological potential in this respect. The paper presents the principles and effectiveness of using an MBR at the Głogów Małopolski operation. Physicochemical tests of raw and treated wastewater as well as microscopic analyses with the use of the FISH (fluorescence in situ hybridization) method were carried out. Moreover, the level of electric energy consumption during the operation of the wastewater treatment plant and problems related to fouling were also discussed. A wastewater quality analysis confirmed the high efficiency of removing organic impurities (on average 96% in case of BOD5 and 94% in case of COD) and suspension (on average 93%).

Open access

Nargis Sahib

Abstract

Moderate management of temporary wetlands is one of the most proper methods for their restoration and conservation. The cessation of use may lead to high biomass domination by macrophytes as Juncus maritimus (Lam.) that changes plant community structure, threatens species biodiversity, and becomes a danger for their conservation. The experiment was carried out in Sidi Boughaba coastal reserve in Morocco. Two management techniques of wetlands were tested, cutting and uprooting of the rush. Four experimental plots (4.2 × 2.9 m) within the rush belt were set up, with intact plots as a control. Vegetation structure and water levels were monitored on 96 quadrats over two years. The six visits dates, three visits per year (February, April, June), were monitored over two years. The abundance and richness of species were studied, simultaneously with the density of the seed stock in each plot. Results showed that both techniques allowed the opening of the habitat with a significant increase of richness and abundance of species, particularly the restoration of characteristic species of the temporary wetland from the seed bank. The cut technique seems to have less of an effect on the seed stock, total seeds median value was 6.5 in cut plots versus 5 in uprooting plots, being regularly applied given the rapid encroachment of the rush.

Open access

Dawid Bedla and Ewa Dacewicz

Abstract

The paper discusses the use of multiclustering statistical analysis in the assessment of domestic wastewater filtration effectiveness. Calculations included data collected over four months of experiments with using waste as filling material of vertical flow filters for domestic sewage treatment. The effectiveness of pollutants removal was analysed in case of mechanically shredded waste in the form of PET flakes, PUR foam trims, shredded rubber tires and wadding. The organic compounds (CODcr, BOD5) removal, suspend solids, biogens (as NH4 +, PO4 3−ions) and oxygen saturation changing compared with sand filling was analysed. Multiclustering statistical analysis allowed to divide pollutants removal efficiency of analysed materials into 3 clusters, depending on the hydraulic loading. The first group consisted in quality parameters of treated sewage: the highest reduction of BOD5 and NH4-N. It included the values of quality parameters and indicators for the filtrates obtained at the lowest hydraulic load from columns filled with 60 cm of rubber tires or sand. The second group comprised the results for fillings containing foam, PET and rubber tires (the other hydraulic loads). It featured the highest reduction of total suspended solids and PO4 3−. Removal of easily biodegradable organic compounds was at a similar level in both cluster groups. The filter filled with polyester waste (wadding), which was as effective as 30 cm layer of sand, and the filters filled with 60 cm of sand working at the highest hydraulic load. Third group showed the lowest values of parameters and indicators for analysed filtrates.

Open access

Farhang Azarang, Mahmood Shafaei Bejestan, Ghazal Jafari and Maryam Karami

Abstract

The materials mining from rivers have a variety of negative and positive effects. Currently, one of the most important issues in river engineering is the proper management of materials mining. In this research, global experiences and international standards for managing sand and gravel mining have been applied to evaluate the mining area in the Zohreh River in Khuzestan province (Iran). One of the evaluation methods in this field is the river matrix method. In this method, which is defined on the basis of river pattern, river characteristics such as river size, site location of materials, associated channel and type of deposit are being considered. In this research, a segment of the Zohreh River between Sardasht Zeydun bridge and Mohseniyeh village in which has good potential for gravel mining was selected and evaluated for river characteristics, mining potential and application of river matrix method. The study indicates that the Zohreh River has a braided pattern in the range. The volume of sediment materials in the target area is about 10 000 m3, the length and width of the mining area are 125 and 80 m respectively, and surface extraction with a maximum depth of 1 m was recommended for extraction of materials. At the end of the research, management solutions and solutions for mining of river materials were presented using various standards.

Open access

Megersa Olumana Dinka and Degefa Dhuga Chaka

Abstract

Land use/land cover changes (LULCC) at Adei watershed (Ethiopia) over a period of 23 years (1986–2009) has been analysed from LANDSAT imagery and ancillary data. The patterns (magnitude and direction) of LULCC were quantified and the final land use/land cover maps were produced after a supervised classification with appropriate post-processing. Image analysis results revealed that the study area has undergone substantial LULCC, primarily a shift from natural cover into managed agro-systems, which is apparently attributed to the increasing both human and livestock pressure. Over the 23 years, the aerial coverage of forest and grass lands declined by 8.5% and 4.3%, respectively. On the other hand, agricultural and shrub lands expanded by 9.1% and 3.7%, respectively. This shows that most of the previously covered by forest and grass lands are mostly shifted to the rapidly expanding farm land use classes. The findings of this study suggested that the rate of LULCC over the study period, particularly deforestation due to the expansion of farmland need to be given due attention to maintain the stability and sustainability of the ecosystem.

Open access

Teresa Jakubczyk

Abstract

The paper presents the results of analysis of duration of precipitation sequences and the amounts of precipitation in individual sequences in Legnica. The study was aimed at an analysis of potential trends and regularities in atmospheric precipitations over the period of 1966–2015. On their basis a prediction attempt was made for trends in subsequent years. The analysis was made by fitting data to suitable distributions – the Weibull distribution for diurnal sums in sequences and the Pascal distribution for sequence durations, and then by analysing the variation of the particular indices such the mean value, variance and quartiles. The analysis was performed for five six-week periods in a year, from spring to late autumn, analysed in consecutive five-year periods. The trends of the analysed indices, observed over the fifty-year period, are not statistically significant, which indicates stability of precipitation conditions over the last half-century.

Open access

Paulo Araldi, Carlos Eduardo Tino Balestra and Gustavo Savaris

Abstract

The present study aimed to analyze the interference of different curing conditions on the development of the concrete compressive strength under the perspective of construction management. It is known that the conditions of humidity and temperature are the main factors related to the behavior of the concrete strength, so that modifying these parameters directly affects the material’s behavior and, consequently, construction management. Forty-two specimens of concrete were molded and each 6 specimens were submitted to different temperature and humidity conditions. The first group was oven-cured at a temperature of 100°C. The second and third groups were kept at ambient temperature of 23 + 2°C being that the latter was submerged in water and the former was exposed to the air humidity. The specimens of groups 4 and 5 were placed in a freezer at 5°C. Group 4 was submerged in water and group 5 was not. The curing of group 6 occurred under submerged condition with water at about 100°C. Group 7, on the other hand, was cured in water vapor. The group submitted to curing at room temperature and submerged condition was the one with the highest compressive strength value, while the ones with the lowest compressive strength were the groups of samples cured in the oven and those submerged at 100°C. The results were compared and tested using statistic methods, which proved that the curing conditions directly affected concrete properties.

Open access

Isabelle Portugal Serrado, João Alberto Neves dos Santos, Nylvandir Liberato Fernandes de Oliveira and Andrey Pimentel Aleluia Freitas

Abstract

Due to the economic crisis, the Brazilian construction companies faced the challenge of remaining competitive in the market, therefore they need to be restructured. Construction projects are intrinsically risky because it changes the environment both physically and socially. Given this complexity and the great exposure to risk, this research aims to evaluate the market risks in construction projects through a field research, analyzing the perception and judgment of professionals in the area. The data analysis was performed by a multivariate index based on the statistical technique Factor Analysis that can be ordered by risk factors by degree of importance. It was possible to confirm the degree of correlation between the subgroups of risk factors and to establish a ranking of the degree of their importance, and the first one considered more relevant was the risk of reducing the quality of the workforce. It was also identified the low maturity in risk management in organizations, even though in civil works a thorough risk analysis is required.

Open access

Mirela Cărătuș Stanciu and Monica Esperance Găureanu

Abstract

In the paper we analyzed the evolution of the number of pig carcasses classified in Romania by the OptiGrade Pro (OGP) semiautomatic method. The analysis was conducted for the period 2009-2015. For this time, the average weight of the carcasses and their quality (thickness of the muscles and the layer of fat) were monitored.