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Open access

Anna M. Baryła

Abstract

Green roofs play a significant role in sustainable drainage systems. They form absorbent surfaces for rainwater, which they retain with the aid of profile and plants. Such roofs therefore take an active part in improving the climatic conditions of a city and, more broadly, the water balance of urbanized areas. One of the factors influencing the hydrological efficiency of green roofs is the drainage layer. In the article, column studies were carried out under field conditions involving the comparison of the retention abilities of two aggregates serving as the drainage layer of green roofs, i.e. Leca® and quartzite grit. The average retention of the substrate was 48%; for a 5 cm drainage layer of Leca® retention was 57%, for a 10 cm layer of Leca average retention was 61%. For a 5 cm layer of quartzite grit average retention was 50%, for 10 cm layer of quartzite grit 53%. The highest retention was obtained for the column with the substrate and 10-centimeter layer of Leca®. At the same time, it was shown that Leca® is a better retention material than quartzite grit. The initial state of substrate moisture content from a green roof appears to be a significant factor in reducing rainfall runoff from a green roof; the obtained values of initial moisture content made for a higher correlation than the antecedent dry weather period.

Open access

Ivan Chajda and Helmut Länger

Abstract

Since the reduct of every residuated lattice is a semiring, we can ask under what condition a semiring can be converted into a residuated lattice. It turns out that this is possible if the semiring in question is commutative, idempotent, G-simple and equipped with an antitone involution. Then the resulting residuated lattice even satisfies the double negation law. Moreover, if the mentioned semiring is finite then it can be converted into a residuated lattice or join-semilattice also without asking an antitone involution on it. To a residuated lattice L which does not satisfy the double negation law there can be assigned a so-called augmented semiring. This can be used for reconstruction of the so-called core C(L) of L. Conditions under which C(L) constitutes a subuniverse of L are provided.

Open access

Mohammed A. Abdulaziz, Abdulrahman A. Bakri, Saleh A. Al-Zahrani, Majed S. Al-Zahrani, Abdulrahman N. Al-Lehebi, Fadil M. Banjar and Mohand I. Nabag

Abstract

This study aims at investigating the potential of Acacia gerrardii pod for the removal of Cr(VI) in batch system. Effect of solution pH, biosorbent dosage, initial concentration of Cr(VI), contact time on the removal process was examined. Complete removal of hexavalent chromium was achieved at pH values 1.0 and 2.0 whereas maximum removal of total chromium was obtained at pH of 3.0. The study showed that the biosorption and bioreduction mechanisms were involved in the removal process. The time required for complete removal of Cr(VI) using the pod of Acacia gerrardii was shortened with an increase in biomaterial dosage and decrease in Cr(VI) concentration. Kinetic data was well described using Park kinetic model. Freundlich isotherm model adequately fitted the equilibrium data indication multilayer adsorption of total chromium on the surface of biomaterial. The pod of Acacia gerrardii could be used efficiently for the removal of hexavalent chromium from aqueous solutions.

Open access

Bahman Jabbarian Amiri, Junfeng Gao, Nicola Fohrer and Jan Adamowski

Abstract

There is an emerging challenge within water resources on how, and to what extent, borrowing concepts from landscape ecology might help re-define traditional concepts in hydrology in a more tangible manner.

A stepwise regression model was adopted in this study to assess whether the time of concentration of catchments could be explained by five landscape structure-representing metrics for land use/land cover, soil and geological patches, using spatial data from 39 catchments.

The models suggested that the times of concentration of the catchments could be predicted using the measures of four landscape structure-representing metrics, which include contiguity index (r 2 = 0.46, p ≤0.05), fractal dimension index (r 2 = 0.51, p ≤0.05), related circumscribing circle (r 2 = 0.52, p ≤0.05), and shape index (r 2 = 0.47, p ≤0.05).

The models indicated that the regularity or irregularity in land use/land cover patch shape played a key role in affecting catchment hydrological response. Our findings revealed that regularity and irregularity in the shape of a given patch (e.g., urban and semi-urban, rangeland and agricultural patches) can affect patch functions in retarding and/or increasing flow accumulation at the catchment scale, which can, in turn, decrease or increase the times of concentration in the catchments.

Open access

Majid Muneer, Muhammad Saeed, Ijaz Ahmad Bhatti, Atta-ul Haq, Muhammad Kaleem Khosa, Muhammad Asghar Jamal and Saddaqat Ali

Abstract

Synthetic dyes are persistent pollutants with poor biodegradability. The present study is about the degradation of direct Congo red dye in aqueous media using the Co-60 gamma radiation source. The experimental conditions such as gamma-ray absorbed doses, amount of oxidant (H2O2) and pH conditions were evaluated. The λmax of dye solution was noted as 498 nm, and then, decrease in absorbance and reduction in chemical oxygen demand (COD) were examined. The complete colour removal of dye was observed at 5 kGy, while a significant COD removal was observed at 15 kGy gamma-ray absorbed dose in conjunction with oxidant for 50 mg/L concentration. It was found that pH has no influence on degradation efficiency. A possible degradation pathway was proposed. The radiolytic end products were monitored by Fourier transform infrared (FTIR) and gas chromatography coupled with mass spectrometry (GC-MS) to explore the degradation mechanism. It was imperative to study the oxidative degradation pathway to provide directions for potential applicability of advanced oxidation process (AOP) in industrial wastewater treatment.

Open access

Ahmed Mostafa and Heba Shaaban

Abstract

The study presents the application of multivariate curve resolution alternating least squares (MCR-ALS) with a correlation constraint for simultaneous resolution and quantification of ketoprofen, naproxen, paracetamol and caffeine as target analytes and triclosan as an interfering component in different water samples using UV-Vis spectrophotometric data. A multivariate regression model using the partial least squares regression (PLSR) algorithm was developed and calculated. The MCR-ALS results were compared with the PLSR obtained results. Both models were validated on external sample sets and were applied to the analysis of real water samples. Both models showed comparable and satisfactory results with the relative error of prediction of real water samples in the range of 1.70–9.75 % and 1.64–9.43 % for MCR-ALS and PLSR, resp. The obtained results show the potential of MCR-ALS with correlation constraint to be applied for the determination of different pharmaceuticals in complex environmental matrices.

Open access

Michael Chukwuma Obeta

Abstract

Water scarcity is a major and growing problem in Nigerian rural areas, leading to the emergence of private for-profit water services providers (PPWSPs). This paper characterizes the landscape of PPWSPs in Nigerian rural communities using information collected from field observations, in-depth interviews, questionnaire surveys, and from published water resources literature. The data collected were analysed through the use of descriptive statistical tools. The results revealed the characteristics, categories, contributions and concerns of water users regarding water supplies by PPWSPs. Responses show that PPWSPs are helping to engender development, guarantee end-users with access to sufficient and reliable supplies and reduce water shortages in the study communities. Sixty four percent of sampled households depend on PPWSPs for their water requirements. Many PPWSPs operate outside the purview of government regulations and have differentiated service modes and prizes to gain wider acceptability. Despite the progress made by PPWSPs, however, the strategy can neither guarantee universal access nor the supply of safe drinking water. Significant barriers to the operations of PPWSPs, how to close the policy-gaps that constrain services delivery by PPWSPs and improve performances through setting of standards and regulatory reforms are discussed.

Open access

A. Tripathi, L. Wangchu and A. K. Trivedi

Summary

This work investigated the relationship of host size, seasons, and water quality parameters with the prevalence and intensity of Cornudiscoides agarwali on Mystus bleekeri collected from the Dikrong River in Arunachal Pradesh, India from February 2016 to January 2017. A total of 2760 specimens of C. agarwali were recovered from 114 individuals of M. bleekeri. The levels of mean intensity, but not the prevalence, of infection of C. agarwali were positively correlated with fish host size, peaking in the largest size class (45.20 ± 5.69 parasites/fish). The prevalence values had a statistically significant seasonal trend, reaching highest (100 %) during the pre-monsoon season, followed by 91.8% during the post-monsoon period and 87.5 % during the monsoon season. The levels of mean intensity of infection were also dependent on the seasons, reaching significantly higher levels during the pre-monsoon season (42.75 ± 4.18 parasites/fish). All water quality parameters measured were within the safety value recommended for freshwater aquaculture. Cornudiscoides agarwali maintained its prevalence above 87.5 % throughout the annual cycle, which means it was able to reproduce year-round in a non-polluted river. This could be an indication of monogenoidean community and population dynamics thriving best under optimum water quality parameters. Also, this article draws the attention of parasitologists and ichthyologists to a taxonomic problem of the misidentification of Mystus spp., and therefore, possibly of their parasitic monogenoids.

Open access

S. Sadet Canakoglu, S. Simsek, I. Balkaya and S. Gunyakti Kilinc

Summary

Fasciolosis caused by Fasciola hepatica is a common parasitic disease of livestock especially sheep and cattle. In this study molecular characterization of β-tubulin isotype 3 gene in Fasciola hepatica isolates from cattle and sheep in Turkey was carried out. For this purpose a total of 80 adult Fasciola hepatica isolates were collected from 20 sheep and 20 cattle in Kayseri and Erzurum provinces. PCR-RFLP was performed on β-tubulin isotype 3 gene and MboII revealed two fragments of approximately 350 bp and 390 bp, whereas HphI enzyme yielded 210, 340 and 540 bp bands, HindII yielded 380 and 450 bp bands in all samples. A total of 80 isolates were tested by SSCP and all of them presented the same band profiles. Six samples (4 sheep and 2 cattle) were randomly selected and DNA sequence of a 935 bp coding fragment of β-tubulin isotype 3 was performed. Sheep samples were more polymorphic than the cattle. This β-tubulin isotype 3 gene polymorphism of F.hepatica isolates from sheep and cattle of two distinct geographical areas of Turkey have been investigated for the first time.

Open access

Jerzy J. Parysek

Abstract

This article presents the general characteristics of the Poznań school of socio-economic geography (and spatial management). Scientific school is usually understood as a community of scholars, representatives of a given scientific discipline, associated with a specific university (or universities) functioning in a given city, united by particular approaches to scientific problems and by accepted ideas, views, methods used etc., which has substantial achievements in a given scientific discipline. There is practically no scientific school without a master (or masters) who is an eminent scholar gathering a group of students and associates. The acknowledged output of this scholar – master, especially an innovative approach to solving research problems and also the influence of his/her scientific authority on students and associates, is usually an origin of a new scientific school. Professor Zbyszko Chojnicki, the founder of the Poznań school, was such a master. The article presents the creation of the School and its development, characterises the role of the Master, indicates the research approach and direction of the conducted studies he determined and discusses the scientific output of the Master and the three selected generations of students and, to a lesser extent, the auditing students. Emphasis is put on the achievements in the theory of geography and spatial management, methodology, paying particular attention to quantitative analysis methods and the innovative and original empirical research conducted as well as the significance of this output for Polish socio-economic geography and spatial management. What is also presented is the popularisation activity and the reflections on the future of the School. The article presents the author’s point of view.