Influence of Nitrate Contamination on the Swell and Compressibility Characteristics of a Tropical Clayey Soil

This research work assessed the influence contaminated groundwater chemistry (especially nitrate contamination) on the volume change behavior during consolidation for a southwestern Nigerian clayey soil. 1-D Consolidation tests using deionized water and various concentrations of nitrate solution as the saturation/inundation liquid were performed on undisturbed clayey soil samples collected from Odi- Olowo Street (nitrate contamination prone area) in Akure, the capital of Ondo state, Nigeria. The compressibility/swell characteristics of the soil are influenced by nitrate contamination, as shown by the variation in the values of the coefficient of permeability, coefficient of consolidation, compression and swell indices (k, cv, Cc and Cs). This implies that the swell potential, magnitude and rate of settlement are affected. These properties directly influence the performance of shallow structural foundations. It was concluded that lack of chemical analysis for soil and groundwater in a nitrate contamination prone area before construction could lead to an overestimation of the swell and compressibility indices for the site. Permeability of the clayey soil increased significantly with increase in nitrate contamination, this portends the danger of emerging breakthrough of contaminants in the shallow contaminated zone through the underlying clayey layer to deeper confined aquifers being relied upon for portable drinking water

The Effects of Transaction Costs on Investor Sentiment: Evidence from the Nigerian Electricity Service Industry

Privatisation of the Nigerian Electricity Service Industry represents a bold first step on a multi-dimensional journey to social and economic development. Significant challenges remain to be overcome. This paper examines the reforms through the lens of New Institutional Economics in order to determine how weak institutions have so far confounded seasoned local investors and international advisors, by looking for the presence of excessive transaction costs. The reform environment is based on Williamsons 4 levels of social analysis and subjected to evaluation based on four areas deemed critical for reform success, namely property rights, market structure, conflict resolution mechanisms and policy implementation capabilities. The study is restricted to investors in electricity distribution companies, and the presence of high transaction costs used as proxy for institutions in need of further improvement. The study finds that providing quality asset performance data and changing a culture that tacitly accept electricity theft and late bill payment, will reduce the transaction costs associated with defining and protecting Investors property rights. However, the regulatory environment must mature to enjoy the confidence of government, consumers and investors, who continue to remain optimistic

Estimation of contaminant transport parameters for a tropical sand in a sand tank model

This research describes the goals, design and implementation of a quasi natural gradient, laboratory scale, sand tank (aquifer) model experiment. The model was used to study the transport of an inorganic tracer (Chloride) in groundwater, within a tropical aquifer (porous medium) material. Three-dimensional sand tank (1.8 m × 0.3 m × 0.8 m) experiments were conducted to investigate contaminant transport and natural attenuation within the sand tank. In all, 360 samples were collected during 24 sampling sessions, for the three days of the tracer experiments in the Sand Tank. The Owena sand is a poorly graded sand with 88.1 % sand and 11.9 % gravel. Geotechnical properties including; coefficient of uniformity Cu = 2.53, coefficient of gradation Cz = 0.181, hydraulic conductivity K = 5.76 x 10-4 m/s, bulk density ρ = 1.9 Mg/m3, effective porosity ne = 0.215 and median grain diameter D50 = 0.55 mm, were determined. Other relevant hydraulic and solute transport parameters, such as dispersion coefficients and dispersivities were also established for the tropical soil

Exploring social value and their enablers as business models for sustainable water supply projects

Purpose: This work aims to understand how social value is created and delivered using community-based water supply projects. It examines social value creation given the enabling concepts – value co-creation and service ecosystems as business models for infrastructure. / Design/methodology/approach: Inductive reasoning, including qualitative research design, was applied to two water supply projects. The qualitative stage created social value co-creation features using the purposive sampling of 72 semi-structured interviews. / Findings: The qualitative analysis features social value co-creation, which includes a sense of social unity, end-user empowerment, Behavioural transformation, and knowledge transfer. Although value destruction also emerged while examining social value co-creation, the research identifies the “red flags” and value contradictions that must be avoided. / Research limitations/implications: The enablers of sustainable infrastructure projects should include social value, service ecosystems and value co-creation. / Practical implications: There is a need for the government and non-governmental organisations to create enabling platforms that involve a planned dialogical communication process supporting the development and enhancement of relationships of stakeholders to maximise social value from infrastructure projects. / Originality/value: The work offers a widened perspective of social value creation and a new framework called “Social value co-creation/destruction” (SVCC/SVCD) as the business model for sustainable infrastructure projects. It is the first attempt to illustrate social value creation in construction from service ecosystems and value co-creation perspectives

Geotechnical Characterization of some Clayey Soils for Use as Landfill Liner

Waste management is one of the major challenges faced by municipality officials, public health engineers and environmentalists in their quest to protect and preserve our environment. Construction and operation of an engineered sanitary landfill ensures proper waste management with the protection of human and ecosystem health. This paper presents the results of geotechnical investigation carried out on clayey soils from three selected pottery areas in Oke Ogun, Oyo State; to assess their suitability for use as landfill liner. Samples were collected at three locations namely: Ajetunmobi village, sample A; Adegbite area, sample B; and Arigangan area, sample C. Basic index characterization tests conducted on the samples revealed percentage fines for samples A,B and C were 32.7%, 28.3% and 37.0% respectively. Specific gravity ranged between and 2 \ub7 71 and 2 \ub7 74. Sample A had Cation Exchange Capacity (CEC) value of 10.58 milli-equivalents/100g (Meq./100g), sample B had CEC value of 11.76 (Meq./100g) and sample C had CEC value of 12.18 (Meq./100g) Geotechnical tests conducted on samples resulted in hydraulic conductivity (k) of 1.86 7 10-10m/sec for sample A ; 4.12 7 10-8m/sec for sample B and, 2.60 7 10-10m/sec for sample C. The results obtained from the study show that sample A is the best material for a landfill liner based on the hydraulic conductivity criterion, however all the other samples are also useful and can be improved by addition of little percentage of bentonite. The compaction and compressibility characteristics needed in the specifications for the construction and operation of an engineered landfill using these clayey soils are presented

Don't make value co-creation ambiguous, social networks simplify it

Purpose: Value co-creation is often necessary for situation where expertise and resources are beyond a single actor. Despite the vast study of value co-creation in service system by both academics and practitioners as an overarching theory, that describes collaboration between consumer and provider. More importantly, little is known about how value co-creation is established in social network analysis and there is little agreement on what depicts value co-creation. These missing concerns included; vast studies of value co-creation in dyadic relationships and sparingly in multi-actors, lack of study on theoretical and empirical features of value co-creation, lack of empirical investigation of strength of interactive relationships in networks for co-creation of specific value-in-use. These thought-provoking missing concerns necessitated this research by forwarding the question; “What are the features of social value co-creation in service system and how can it be established in social networks”? Methodology: A case study approach is employed using the exploratory sequential mixed methods. The contextual investigation was carried out in water supply system called KAMOMI. The KAMOMI water scheme provides water supply facility and has in place a service system consisting both the provider, consumers and different stakeholders. The case represents a service system where value co-creation occurs within actor-to-actor interactive relationships to benefit the community. Findings: The paper argued that the examination of value co-creation among multi-actors in social networks analysis is highly significant to its cogency and generalisation. The qualitative analysis provided evident features of value co-creation, which transforms value co-creation from dyadic to multi-actors interpersonal interactive relationships in social network analysis. The value co-creation features included resource integrating networks, defined value-in-use, actors’ empowerment, perceived ownership and knowledge sharing. Meanwhile, the quantitative analysis discovered that closeness of both formal and informal relationships; including frequency of informal interactions enable access to integration of resources of multi-actors for value co-creation. Contribution: The study of value co-creation in social network analysis represents an interesting gap and is highly essential for designing effective service system to enhance the goal of value co-creation. The paper contributes by illustrating (a) features of value co-creation in networks (b) empirical evidence of how strength of relationships of actors enhance resource integration in networks

Design of an engineered landfill as possible replacement for an existing dump at Akure, Nigeria

This work focuses on the design of an engineered (semi-aerobic) landfill in Akure with a view to encourage a shift from the use of a dumpsite, which despite its adverse environmental impact has remained the method of waste disposal in Nigeria. Topographic maps, population figures, per capita waste generation and laboratory geotechnical investigation provided some of the basis for the landfill design. The waste generation potential of Akure and the leachate generation and gas emission potentials of the landfill were estimated. The cumulative waste generation potential of the landfill over its 15 years life was estimated to be 5.89 × 106m3 (2.18 × 109 kg) and the landfill will require a dimension of 935 m × 905 m × 10 m. The geotechnical tests revealed the proposed site will not yield under landfill loadings, while the hydraulic conductivity and consistency properties of the borrow pit soil samples show that they are suitable for use as liner materials. The design is composed of specifications for a liner, a capping system, leachate collection using a high-density polyethylene (HDPE) pipe system, gas capture and monitoring systems against leachate and landfill gas migration from the landfill. This research work will form readily accessible reference material for the design of engineered landfill in developing countries

In search of the holy grail: An exploration of value Co-Creation in service ecosystems using knowledge network analysis

The intention of this article is to simplify the study of value cocreation both from a deeper theoretical discourse, including knowledge networks approach. The study's approach is from the perspective of knowledge sharing, in form of interaction and resource integration. We outline the central premises of value cocreation as fundamental in service ecosystems and resource integration concepts. It is also expounded how not just interaction, but how service interaction enhances value co-creating processes, by enabling an actor to enter the value creating processes of other parties, support them, and benefit from them. The article does emphasize processes of value co-creation, including its outputs and outcomes. Knowledge sharing is encapsulated within the concepts of resource integration and service interaction among actors. The knowledge network analysis technique is used as a methodology, while preliminary data from KAMOMI water supply service is used as a case illustration. The case is used to tentatively indicate how resource integration and interaction seem to influence value co-creation, while also using knowledge network analysis quantitatively. Two models are developed. The first model exemplified the theoretical drivers of value cocreation, while the second described the structural characteristics that influence value co-creation in form of knowledge sharing. Four propositions are advanced to supplement the study’s theoretical insights. Given the perspectives of knowledge networks, the article makes knowledge contribution to the ongoing academic debate on value co-creation in service ecosystems

The Stabilization of Weathered Dolerite Aggregates with Cement, Lime, and Lime Fly Ash for Pavement Construction

An experimental program was performed on weathered dolerite specimens stabilized by adding varying percentages of cement (4, 8, 12, and 16) % and lime (6 and 12) % and a combination of lime and fly ash (6% lime + 12% Fly ash and 12% lime + 12% Fly ash) % by dry weight of soil. The strength was examined under three different curing methods, namely, membrane curing (MBC), alternate moist-air curing (MAC), and water curing (WAC), by conducting unconfined compressive strength (UCS) tests. Simple polynomial and linear functions (regression models) were used to define the relationships between the variables investigated. Membrane curing (MBC) gave results close enough to the water curing (WAC) to indicate that it can be confidently used on the field during pavement construction. From the results obtained, for class B (interurban collector and major rural roads) pavement construction, addition of 8% cement was recommended for road base construction with stabilized WDA. Also the addition of 12 + 12% Lime and Fly Ash was recommended for road subbase construction with stabilized WDA. Stabilized WDA against the prejudiced myths would perform satisfactorily for base and subbase construction in both heavily trafficked and low volume roads with economic quantities of cement, lime, and fly ash in South Africa

Contamination potential of tar sand exploitation in the western Niger-Delta of Nigeria: baseline studies

Exploitation of the tar sands in Ondo State in the Niger Delta is likely to result in some environmental contamination and adversely affect the living conditions of the farmers and fishermen in the area. Three wells were established where samples were taken at 1, 2 and 3 m depth. Although no hydrocarbon contamination was detected in the water from the surface and boreholes, saline intrusion was recorded. This study produces a baseline against which future contamination can be monitored so that preventative measures can be taken to mitigate the effects