bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of ignition protocol on grassfire development
Authors: Sutherland Duncan , Sharples Jason J. , Moinuddin Khalid A. M.
Published: November 2019

The effect of ignition protocol on the development of grassfires is investigated using physics-based simulation. Simulation allows measurement of the forward rate of spread of a fire as a function of time at high temporal resolution. Two ignition protocols are considered: the inward ignition protocol, where the ignition proceeds in a straight line from the edges of the burnable fire plot to the centre of the plot; and the outwards ignition protocol, where the ignition proceeds from the centre of the burnable fire plot to the edges of the plot. In addition to the two ignition protocols, the wind speed, time taken for the ignition to be completed and ignition line length are varied. The rate of spread (R) of the resultant fires is analysed. The outwards ignition protocol leads to an (approximately) monotonic increase in R, whereas the inward ignition protocol can lead to a peak in R before decreasing to the quasi-equilibrium R. The fires simulated here typically take 50m from the ignition line to develop a quasi-equilibrium R. The results suggest that a faster ignition is preferable to achieve a quasi-equilibrium R in the shortest distance from the ignition line.
Spatial and temporal pulse shaping for lateral and depth resolved two-photon excited fluorescence contrast
Authors: Kussicke A , Tegtmeier M , Büchau F , Heyne K , Lindinger A
Published: November 2019

We report combined temporal and spatial laser pulse shaping to perform lateral and depth dependent two-photon excited fluorescence of dyes. For generating the specific spatially and temporally phase tailored pulses a temporal pulse shaper and a subsequent spatial pulse shaper are employed. Simultaneous spatial and temporal shaping is presented for two-photon excited fluorescence by applying temporal third order phase functions on spatially different light field components. Moreover, the prospects of spatial shaping are demonstrated by applying various lateral two-photon fluorescence pattern. In particular, a depth dependent excitation of different dyes is performed which leads to a high axially resolved fluorescence contrast. The introduced spatial and temporal shaping technique provides new perspectives for biophotonic imaging applications.
Conference key agreement with single-photon interference
Authors: Grasselli Federico , Kampermann Hermann , Bruß Dagmar
Published: November 2019

The intense research activity on Twin-Field (TF) quantum key distribution (QKD) is motivated by the fact that two users can establish a secret key by relying on single-photon interference in an untrusted node. Thanks to this feature, variants of the protocol have been proven to beat the point-to-point private capacity of a lossy quantum channel. Here we generalize the main idea of the TF-QKD protocol introduced by Curty et al to the multipartite scenario, by devising a conference key agreement (CKA) where the users simultaneously distill a secret conference key through single-photon interference. The new CKA is better suited to high-loss scenarios than previous multipartite QKD schemes and it employs for the first time a W-class state as its entanglement resource. We prove the protocol’s security in the finite-key regime and under general attacks. We also compare its performance with the iterative use of bipartite QKD protocols and show that our truly multipartite scheme can be advantageous, depending on the loss and on the state preparation.
The probability determination of the queuing system state of the motor transport enterprise
Authors: Bulatov S V
Published: November 2019

The article describes the queuing system by the example of one-passenger motor transport enterprises for the purpose of carrying out the analysis of the applications flow for spare parts, the conditions identifications of the formation of the waiting list. All this including the determination of the optimum number of the service stations for units and sets will allow serving in due time the rolling stock without idle times.
The synthesis of motion laws for cam mechanisms with additional movement of the follower
Authors: Podgornyj Yu I , Skeeba V Yu , Kirillov A V , Martyushev N V , Borisov M A
Published: November 2019

The research discusses the design of cam mechanisms for special purposes. The analysis of the scientific literature on this issue indicates that at present the synthesis of the cam mechanisms motion laws is carried out mainly using a standard set of acceleration curves or displacements. In some cases, the designer needs to synthesize an acceleration law which should be task-specific and provide for a certain production step. Additional areas on the cam profile which perform specified motions of the follower are very important for the synthesis of such mechanisms. There may be several areas of this type. The relevance of the study is due to the fact that the mechanisms that work using a time-compressed cyclic diagram cannot be modernized on the basis of the existing methods for the synthesis of cam mechanisms; therefore, it is not possible to enhance the performance of such mechanisms without a significant change in the laws of motion.
Determining the operational loads of the hybrid metalworking machines drive
Authors: Skeeba V Yu , Skeeba P Yu
Published: November 2019

Numerous studies are devoted to determining the operational loads of metalworking machines. They employ various approaches including those based on analytical methods of calculation. However, their use is not always appropriate, since they do not take into account many features characteristic of the actual operating conditions of hybrid metalworking machines. The article proposes a universal method of substantiating the performance specification of the integrated machine-tool equipment based on mathematical modeling of its operating conditions. This technique allows generating objective data on the design loads of machine tools, which enables providing the necessary level of reliability of newly designed machines that have no analogues. The proposed approach provides the possibility of using automated design systems at the initial stage of creating the general concept of new process equipment.
Changes in formation pressure and technological efficiency of unsteady flooding in double permeability reservoirs having different productivity rates
Authors: Almukhametova E M , Soloviev N N
Published: November 2019

Unsteady waterflooding went through several stages. Within the pilot works in April 2009, cyclical water injection was started in Block 7 (central section). In addition, alternate water injection into the horizons of the Jurassic and Cretaceous sediments of Block 10 began. For this purpose, injection wells equipped with devices for simultaneous separate water pumping were used. The significant effect of non-stationary waterflooding in the experimental sections allowed for the application of the technology in other blocks. The technology implementation scheme was applied for injection wells of Blocks 6 and 10. Since July 2010, cyclic injection has been used for many wells. Periods of non-stationary operation of injection wells were determined experimentally. The reservoirs with heterogenous permeability containing highly permeable and low-permeable layers are the most optimal ones. The heterogenous structure of the reservoir provides a large contact area between layers with different permeability levels which allows for non-stationary effects due to the occurrence of overflows between the layers. It can reduce the water content of the products and increase oil production.
Modeling the processes of substantiation of renewable energy development projects
Authors: Alabugina R A , Zhang Z , Xue W , Ma D
Published: November 2019

The features of the assessment of the economic efficiency of energy saving projects based on the combination of traditional and renewable energy and material resources with an increasing degree of cogeneration of energy types and by-products are revealed. The object of the research is the formed energy-technology complex of objects or the industrial park, and the subject is the modeling of the processes of combining and cogeneration to determine the options for the best organizational and technical solutions in projects for the development of renewable energy. The variants of projects for the transformation and landfill reclamation of an industrial area with a critical level of environmental pollution are substantiated.
Limitations of using phase change materials for thermal energy storage
Authors: Lebedev V A , Amer A E
Published: November 2019

The use of a phase change materials (PCMs) is a very promising technology for thermal energy storage where it can absorb and release a large amount of latent heat during the phase transition process. The issues that have restricted the use of latent heat storage include the thermal stability of the storage materials and the limitation of the container size. The study of the influence of thermal cycling on the properties of PCMs, such as melting temperature and latent heat, is important. It is found that the paraffin wax and fatty acids (e.g., lauric acid, myristic acid, palmitic acid, and stearic acid) have good thermal stability and can be used for solar thermal energy storage applications. However, Calcium chloride hexahydrate (CaCl2. 6H2O) is a good PCM in building applications.
Higher harmonics and limiting thereof in power supply systems of different voltages
Authors: Kostin V N , Serikov V A , Sherstennikova I A
Published: November 2019

The simulation of the modes of power supply systems of different voltages, with a transformer carrying linear and non-linear loads and a capacitor bank, has been implemented. The dependences of the capacitors overload by current and the coefficient of harmonic voltage components on the capacitor bank capacity within the operating range of the transformer total load by linear and non-linear loads have been obtained. For the systems under consideration, upon a daily variation in the capacitor bank linear load and capacity, it is virtually impossible to eliminate the capacitors overload by higher harmonic currents and observe regulatory voltage quality requirements. Anti-resonant chokes installation in the capacitor bank circuits reduces the overload of capacitors to a permissible value, and brings up the coefficient of harmonic voltage components to values that took place in the absence of the capacitor bank.
Vibration state of technical facilities
Authors: Gozbenko V E , Kargapol’tsev S K , Karlina Yu I , Karlina A I
Published: November 2019

Approaches to the management of the vibration state of vibration machines and process flows are considered by introducing additional couplings into the structure of the mechanical system. Based on the structural diagrams, amplitude-frequency characteristics are obtained. The expressions for the minimum amplitude-frequency characteristic are found.
Impact of design capacity on optimal parameters of freight aerial mono-cable cableways
Authors: Lagerev A V , Lagerev I A , Tarichko V I
Published: November 2019

Freight aerial cable roads are an efficient mode of transport in mining industry. The purpose of the paper is to develop the method of optimal design of a mono-cable freight ropeway thus reducing the cost of its construction. It is shown that the pitch and height of intermediate supports, the tension force of load-carrying-traction ropes exerts the main influence on the cableway cost. The problem of conditional nonlinear optimization of the mentioned factors ensuring the minimum cost of a cableway at different design capacity up to 600 t/h is formulated and solved. The optimization task is solved taking into account the necessary design, assembly, deformation and strength limitations. Regularities of change of optimal parameters of intermediate supports and load-carrying and traction ropes at the change of design capacity of a cableway were revealed on the basis of analysis of performed calculations. The results of this optimization task allows significantly reducing the cost of construction of freight aerial cableways.
A review on methods of oil saturation modelling using IRAP RMS
Authors: Tikhomirova E A , Sagirova L R , Khaibullina K Sh
Published: November 2019

Oil saturation is one of the most important characteristics of the reservoir. In the process of geological modelling proper distribution of oil saturation is one of the main parameters for reserves assessment and further flow simulation. The paper presents methods of three-dimensional modelling of oil content of the reservoir based on the results of well log interpretation data, capillarimetry and 3D-trends and algorithms of their realization in reservoir characterization and modelling software suite IRAP RMS, their theoretical basis and application factors.
Identification of the life of mining enterprises in context of reclamation processes
Authors: Kislyakov V E , Bobrov S A
Published: November 2019

The article proposes a methodological approach to determining the full life of mining enterprises, considering the mining and biological processes of land reclamation. It also describes the working area of the strip-pit with elements of stripping, mining and reclamation operations, which predetermine its contour and establish the main parameters of the working area, and the technology of opencast mining in the development of flat deposits. The paper also describes the time (the number, sequence, and duration of the mining and biological reclamation processes at the enterprise facilities) when it is necessary to achieve certain economic indicators based on calculations of mining operations efficiency by year.
The application of thermal gas treatment of the Bazhenov formation
Authors: Sarancha A V , Mikhaylov S.Yu.
Published: November 2019

A large number of publications devoted to the oil production from the Bazhenov formation was published in the Russian scientific and technical magazines focused on specialists in development of oil and gas fields in the last 5 – 10 years. It is connected with the fact that traditional resources of hydrocarbons are gradually reduced, forcing the oil-extracting companies to pay more and more attention to shale oil which the greatest quantity in the Russian Federation occurs in the Bazhenov formation. The main objective of this paper is a review of obtained results of development of the Bazhenov formation on the Middle field.
Packer design research used in hydraulic fracturing
Authors: Verisokin A E , Vasil’yev V.A. , Gun’kina T A
Published: November 2019

The purpose of the packers is determined by the specific technological tasks. The design of a packer and the principle of bringing it into action provide protection from ealy wear during the tripping process. In addition, the design of a packer ensures manufacturability of its use and reliable control over the work in the well during the hydraulic fracturing, regardless of the depth of the installation. The experience with the use of packers for the test beds showed that in most cases packer items become inoperative due to the destruction of the lower part of the rubber element. In practice, the isolation annulus packer with different ways of planting is important and necessary to ensure reliable fixing of a packer at the place of installation in the borehole. It happens due to the use of anchoring unit and different designs of seals of packers.
Restoration of intake capacity of injection well by vibrations
Authors: Zaripova L M , Gabdrakhimov M S
Published: November 2019

Nowadays deterioration of productivity and intake capacity of wells cause different problems in exploitation of oil and gas fields. It happens because of some irreversible physicochemical processes in the bottomhole formation zone: swelling of clay materials, colmation, formation of stable emulsions, confluence of salts, iron oxides etc. Various methods and technologies are used to solve these problems. However, they have disadvantages, for example, material and energy intensity, short-lived equipment, technological complexity. The method of pulse action by various vibrations seems to be the most effective solution. Vibrations are mechanisms that create controlled fluctuations of the working body influencing a recycled material and a reservoir. Now they are widely used in different industries.
Impact of Security on Rental Price of Residential Properties: Evidence from South Africa
Authors: Odubiyi T B , Oguntona O A , Oshodi O S , Aigbavboa C O , Thwala W D
Published: November 2019

The property market plays a vital role in the economy through the provision of constructed space for productive activities and employment opportunities. Evidence gleaned from the literature suggests that the level of security within an area affects property prices. In the current study, the distance between a property and the police station was used as a proxy variable for measuring the perceived level of security. The data on rental prices of residential properties and its attributes were retrieved from a reliable property source (www.property24.com). A Neural network model was used for evaluating the impact of the presence of a police station on rental prices of residential properties within Cape Town, South Africa. Experimental results showed that the developed model is 77.27% accurate when used to predict the rental prices of residential properties. Floor area, number of bathroom, number of bedroom and proximity of a police station have the most significant impact on the rental price of residential properties. Greater efforts are needed to provide insights into the effect of sustainability on rental prices of residential properties. This information would serve a justification for embedding sustainability into residential construction projects.
Appraisal of risk contingency planning for construction projects
Authors: Akinradewo O , Aigbavboa C , Oke A , Coffie H
Published: November 2019

Risk contingency plan in a construction project allows for flexibility and effective responses to change orders and unforeseen risks arising at the construction phase of projects. A poor risk contingency allowance can result in cost overrun on a project as well as time overrun. However, a good risk contingency plan can be tailored based on the previous similar projects while taking into consideration the individuality of that particular project. The aim of the study is to review risk contingency planning for construction projects. Secondary data was used in carrying out this research study. Extant literatures were reviewed carefully for proper understanding of the methods used in carrying out risk contingency estimation, the importance of risk contingency to construction projects, the categories of risk contingency plans and the factors affecting the accuracy of risk contingency for construction projects. The study revealed and concluded that risk contingency serves as the extra budget that caters for uncertainties which can lead to cost overrun on construction projects thereby affecting the accuracy of the preliminary estimate. It was recommended that risk evaluation must be done appropriately at the planning phase of the construction project, so that the estimator can have more information necessary to factor into the estimation process thereby increasing the accuracy of the estimate prepared.
An assessment on the drivers and obstacles of sustainable project management in South Africa: A case study of Johannesburg
Authors: Ohiomah I , Aigbavboa C , Thwala W D
Published: November 2019

The construction industry has been identified as the industry which carry out unsustainable practices, and processes, this has led to several countries seeking to incorporate sustainable practices such as sustainable construction, sustainable construction project management to handle the growing concern over climate and environmental issues. Despite the construction industry awareness of these sustainable practices, it has been a problem implementing these sustainable practices. The aim of this study is to identify the barriers that hinder the implementation of sustainable project management in the South African construction industry, as well as drivers that encourages the implementation of sustainable project management. A quantitative methodology approach was adopted for this study, a questionnaire was employed to gather data for this study. A total of fifty-two (52) respondents returned their questionnaires. Findings from this study reveal that a major barrier to implementation of sustainable project management is the perception that green buildings are expensive, lack of expertise and lack of training also obstacles of the implementation of sustainable project management. Findings on what drives organisations to invest in sustainable project management is the benefits that will be gained financially This study concluded with recommendations stating that an increased level of training and drumming interest in the clients so that when the construction professionals propose the use of sustainable project management, there is an understanding by the clients.
Evaluation of the use of modern technologies for effective material management in South African construction industry
Authors: Odubiyi T B , Oke A E , Aigbavboa C O , Thwala W D
Published: November 2019

A vital building block for construction project globally is construction materials which are huge, costly and are often delivered in great quantities to the construction sites. One of the key roles in the successful completion and delivery of a project is effective construction materials management. However, it has been established that material wastage is a prevalent problem in developing countries which can be tackled with modern technologies for effective material management. It is based on this assertion that this paper focuses on the challenges to use of modern technologies for effective material management in the South African construction industry. The study adopted a quantitative approach where questionnaires were administered to professionals in the South African construction industry. Descriptive statistics tools were used to analyse the gathered data. Findings showed that the common challenges to using of modern technologies for effective material management in the construction in South African are; Scale of construction projects, Cultural barriers, environment challenges, financial challenges, and Behaviours of people in key positions. The way forward are; change in business approaches and procedure, and implementation of skill set is necessary
Awareness, benefits and drawbacks of net zero energy building practices: construction industry professional’s perceptions
Authors: Nduka D O , Ede A N , Oyeyemi K D , Olofinnade O M
Published: November 2019

In a bid to overcome climate change and global warming, the adoption of net zero energy building (nZEB) practices in construction projects has become a viable measure of reducing energy consumption and CO2 emissions in buildings. nZEB is a facility with a significantly lowered energy needs such that the rest of the energy requirements can be supplied by on-site or off-site renewable technologies. The present study therefore investigated the awareness, benefits and challenges confronting the actualization of nZEB in Nigeria construction industry. A cross sectional survey design was adopted wherein a close ended questionnaire was purposively administered online to construction industry professionals who have understanding of nZEB initiatives. Descriptive statistical tests were conducted, with the results showing about 9% and 25% of the selected professionals been not aware of nZEB concepts and have not been involved in the concept in their professional career. Further details revealed that reduction in the land use effect, reduction in vulnerability of power infrastructures to vandalism and economic competitiveness were dominant benefits of nZEB practices. However, low return on investment, conflict with public policy regulation and policy clarity, lack of evaluation and valuation processes were perceived as the top hindering factors to nZEB practices. The implication for practice is for construction stakeholders to participate and develop effective implementation strategies towards nZEB for could be ecological and economical friendly.
Quality of low-income housing projects in South Africa
Authors: Aigbavboa C , Oke A , Akinradewo O , Aghimien D , Okgonne S
Published: November 2019

One of the major duties of any government is to ensure that there are enough houses for the citizen. In view of the shortage, government and many private organisations have been involved in the provision and production of houses for the populace. It is therefore necessary to examine the level of conformance of these houses to acceptable level of quality. Several literature materials were reviewed and various factors causing low quality of buildings were extracted accordingly. To examine these factors, quantitative research method was adopted through administration of close-ended questionnaires on relevant construction professionals, which include Quantity Surveyors, Construction Managers, Architects, Engineers, Town Planners and Project Managers who have been involved in low-income housing projects in South Africa. Factors that contributes to non-adherence to required quality in low-income housing projects are poor site management, less focus on quality and much on production, focus on time by contractor, inadequate contractor’s quality expertise and usage of inexperienced personnel. The implication of these are tarnished image of the professionals involved in the project, defective buildings, unsafe structures and cost overruns. In order to ensure conformance to quality of these houses, contractors that handles construction of low-income houses should be knowledgeable with the National Builders Regulations and there should be monitoring and sufficient inspection of work in progress. Other measures include training and education of stakeholders, use of skilled labours, planning and risk assessment as well as use of appropriate construction materials.
Perception of professionals on causes of structural cracks in concrete buildings
Authors: Olofinnade O M , Busari A A , Akinwumi I I , Awoyera P O , Ekanem J
Published: November 2019

Of recent, the incessant collapse of buildings in some major cities in Nigeria has become a major concern to professionals in the construction industry and the general public because it has resulted in most cases loss of lives and valuables which could affect our attaining the sustainable development goals (SDGs). One of the key features that affect the quality of built structures and usage is crack. The occurrence of a crack in a structural member can weaken the member and eventually lead to building failure and outright collapse. This paper examines the perception of professionals in the Nigeria building industry on the causes and impact of crack on built structures. Primary data were obtained through questionnaires administered to practising professionals within Lagos state. Results obtained from the majority of the professionals indicate that occurrence of a crack in the building is majorly caused by foundation settlement, poor selection of construction materials and technique, design error and corrosion of the steel bar and thus have a significant impact on the structural integrity of the building. It was concluded by proposing certain preventive measures to mitigate crack in buildings so as to prevent possible building failure and attainment of the SDGs.
A comparative study on the strength characteristics of Grade 25 and Grade 30 rice husk ash blended cement concrete
Authors: Igba UT , Akinyele JO , Ehikhuenmen SO , Oyebisi SO , Omotainse PO , Anyanwu BU
Published: November 2019

Rice husk ash (RHA) is an agricultural waste which is a pozzolanic material that can be blended with cement in producing concrete. This research presents investigation carried out on the comparative strength characteristics of concrete produced with grade 25 and grade 30 cement blended concrete using a replacement level of 10% rice husk ash as substitute. Two mix ratios (1:2:4 and 1:1.12:3.01) were used. A total of 60 cube size of 150mm were cast, tested and their mechanical properties determined. The RHA was made in the laboratory by burning the husk obtained from Ifo in Ogun State Nigeria using an Electric furnace, with the temperatures of the furnace at about 700°C. The results showed that the compressive strength at 28 days decreased as the percentage replacement of Portland Limestone cement (PLC) with RHA increased from 0% to 10% respectively with compressive strengths of 29.78 N/mm2 to 21.56 N/mm2 for grade 25 concrete and 32.12 N/mm2 to 26.82 N/mm2 for grade 30 concrete. It was concluded that RHA replacement in concrete can be used for the production of concrete for light structural works in the development of sustainable and green structures.
Assessing the awareness level of biomimetic materials and technologies in the construction industry
Authors: Oguntona O A , Aigbavboa C O
Published: November 2019

The continuous patronage and utilization of unsustainable construction technologies and materials have been identified as one of the major constraints to realizing the sustainability goals of the construction industry. By proliferating and saturating the construction market with materials and technologies with eco-friendly attributes, the negative environmental impacts of the industry will be grossly mitigated. Hence, the adoption of biomimetic materials known to be novel, effective and efficient in this task as a result of their sustainable credentials. This research paper is aimed at assessing the awareness level of biomimetic materials and technologies in the construction industry. A questionnaire survey was conducted on construction professionals to evaluate their level of awareness. A quantitative approach to data analysis was employed using the mean scores of the variables identified. It is established that there is a low level of awareness and familiarity with biomimetic materials and technologies among construction professionals. Raising awareness level, education and government intervention are few among the recommended ways of bridging the knowledge gap on the use of materials and technologies inspired by nature.
Sustainable pervious concrete incorporating sorghum husk ash as cement replacement
Authors: Tijani M A , Ajagbe W O , Ganiyu A A , Agbede O A
Published: November 2019

The sustainability of Pervious Concrete (PC) can be enhanced by the utilization of waste materials for its construction. Employment of Sorghum Husk Ash (SHA) in partially replacing binder to produce a more sustainable PC was carried out in this research. Preparation of various mixtures of PC was done adopting the same size of aggregate (4.75 – 9.50), the same water/cement ratio (0.4) as well as the same aggregate/cement ration (4:1) and was investigated at 0, 5, 10, 15, 20 and 25 % substitution levels of binder with SHA. Produced PC samples were tested for density, porosity, permeability and compressive strength. The results revealed that density decreased while permeability and porosity raised with rising percentage of SHA. Fresh density was obtained to range from 2000 to 1965 kgm−3 whereas hardened density ranged between 1981 and 1940 kgm−3, 21.5 to 24.5 % values were obtained for porosity while permeability had values of 4.8 to 10.1 mms−1 for 0 - 25 % SHA correspondingly. The compressive strengths of 8.2 Nmm−2 was achieved for 25% SHA and 11.4 Nmm−2 for 0 % at 28 days curing time. The 5% SHA was found to be 13.2 Nmm−2 which is 16 % greater than 0 % SHA PC while that of 10 – 25 % correspondingly reduced by 4.4 - 28.1 %. The research revealed that SHA can practically be utilised to substitute cement with comparable and even make a better mixture than using 100 percent cement in PC fabrication.
Effect of various types and sizes of aggregate on self-compacting concrete
Authors: Olowofoyeku A M , Ofuyatan O M , Oluwafemi J , David O
Published: November 2019

Aggregates play important role in concrete; it serves as Structural fillers which are used in concrete production. Aggregate sizes, types and gradation are the most important factor when selecting aggregate. This study examines incorporating different sizes and types of coarse aggregate. Testing rheology and strength of self-compacting concrete mixes at varying sizes and different types of coarse aggregate. The various aggregate sizes used in the Various mixes are 10, 12.5 and 20mm, the types of aggregate used are granite, gravel and ceramic tiles and superplasticizer used is Conplast SP 430 with water cement ratio of 0.45. slump flow test, T50, L-box and V-funnel test were carried out on the various mix to determine the fresh properties of the concrete mix. The mechanical properties (compressive, flexural and split tensile strength test) were conducted on the mixes at different curing age (7, 21 and 28 days). The aggregate size 10mm and granite types had the highest slump flow for the fresh test. It was observed from the mechanical test 10mm and 12.5mm granite size had a higher strength than gravel and ceramic tiles.
Effects of basalt fiber in lightweight expanded clay concrete on compressive strength and flexural strength of lightweight basalt fiber reinforced concrete
Authors: Chiadighikaobi P C
Published: November 2019

The percentages, lengths and diameters of chopped basalt fiber in concrete mixture have high influence on concrete strength. On the other hand, expanded clay contributes mostly in the weight reduction of the concrete hereby, giving what is called lightweight concrete. The collapse of concrete structures can be blamed to the effect of cracks that are born in the weak concrete structures. This paper shows how expanded clay with chopped basalt fiber of length 20mm, diameter 1.5µm affected the maximum load that the concrete samples bear and how the existence expanded clay and basalt fibers affect the concrete in terms of resistance to cracks seen through the bending (flexural) and strength on compressive of the concrete samples. The purpose of this research paper is to investigate the effect of chopped basalt fiber with expanded clay in strengthening the mechanical behaviour of concrete. Concrete specimens were mixed with chopped basalt fiber and casted, the strength checked on 7th, 14th and 28th day and evaluated based on flexural strength, compression strength. The addition of basalt fiber in the specimens showed significant effect where the compressive strength decreased while the flexural strength increased.
Effects of rest period on the strength performance of geopolymer concrete
Authors: Oyebisi S , Ede A , Olutoge F , Igba T , Oluwafemi J
Published: November 2019

The study investigated the effects of rest period on the short-term mechanical property of geopolymer concrete (GPC) that could possibly be easy to embrace in the field to achieve an optimum strength performance. The study utilized both corncob ash (CCA) and ground granulated blast furnace slag (GGBFS) as sustainable construction binders with a view to building sustainable infrastructure. Also, sodium silicate gel (Na2SiO3) and sodium hydroxide (NaOH) solution was used as an alkaline activator, and prepared in 14 molar concentration of NaOH pellets using a mix ratio of grade 30 MPa and grade 40 MPa concretes. GGBFS was substituted in 0, 20, 40, 60, 80, and 100% by volume of CCA. The rest periods (RP) for the fresh concrete were selected as 1, 2, 3, 4 and 5 days before being demoulded. Thereafter, the concrete samples were removed from the moulds and cured under ambient conditions for 7, 28, 56 and 90 days. The compressive strength of the hardened concrete samples was then determined. The study findings reveal an optimum strength performance at 4 days rest period for all classes of concrete produced when compared with 1, 2, 3 and 5 days. Thus, this result can be practically employed and incorporated in the design of geopolymer concrete and at the construction site.
Morphological characterization and physio-chemical properties of nanoparticle - review
Authors: Afolalu S A , Soetan S B , Ongbali S O , Abioye A A , Oni A S
Published: November 2019

The discovery by researchers that the physio-chemical properties of a substance can be influenced by size led to a realization of the importance of Nano particles. Due to its excellent characteristics, these materials have been a source of interest for researchers in multidisciplinary fields. The morphological features of nanoparticles always garner prodigious attention because of the influence morphology has over most of the Nanoparticles’ properties. This review provides insight to the morphological characterization and physio-chemical of its properties.
Housing crisis: Waste glass-stabilized clay for use as fired clay bricks
Authors: Akinwumi I I , Ajayi O O , Joshua O , Sani R , Olofinnade O M , Awoyera P O , Ogundairo T O , Ogunwole D A , Afolayan O D
Published: November 2019

Scarce and expensive housing and consumer waste disposal are global challenges in today’s world. This study investigated the engineering properties of a clay stabilized with three waste glass sizes (less than 75 μm, greater than 150 μm but less than 75 μm, and less than 300 μm but greater than 150 μm) for the production of burnt clay bricks for earth building construction. Laboratory tests (sieve analysis, Atterberg limits, specific gravity, and compaction tests) were conducted on the clay soil sample, while firing shrinkage, water absorption, unit weight and compressive strength tests were conducted on the fired clay bricks. The unit weight, firing shrinkage and compressive strength decreased with an increasing particle size of the waste glass in the fired clay bricks, while the fired clay bricks absorbed more water as the particle size of its waste glass content decreased. The use of waste glass with particle sizes less than 75 μm for stabilizing the clay was found to produce fired clay bricks with the highest compressive strength. The compressive strength of the fired clay bricks containing less than 75 μm particle sizes of waste glass was increased by 43.9% when compared with the compressive strength of the fired clay bricks having no waste glass. Consequently, waste glass with particle sizes of less than 75 μm is recommended for use in the production of fired clay bricks. The use of waste glass, which could have been a nuisance to the environment, is a potential way of improving the strength of bricks and making them more affordable bricks and consequently, making housing more affordable.
Unconfined Compressive Strength of Lateritic Soil Treated with Bacillus Coagulans for use as Liner and Cover Material in Waste Containment System
Authors: Osinubi K J , Yohanna P , Eberemu A O , Ijimdiya T S
Published: November 2019

The innovative and environmentally friendly Microbial Induced Calcite Precipitation (MICP) technique involves the use of micro-organisms to facilitate soil improvement. Urease positive bacteria in the company of urea and calcium sources formed dissolved ammonium and inorganic carbon, carbon dioxide and subsequent formation of calcite which is a pore filling material that stiffens the soil and improve its strength. The study involved assessing the potential of Bacillus coagulans(B.coagulans) to improve the unconfined compressive strength (UCS) of lateritic soil. The soil samples were treated with 1/3 pore volume B. coagulans suspension densities of 0, 1.5×108, 6 × 108, 1.2 × 109, 1.8× 109 and 2.4 × 109 cells/ml, respectively. Soil specimens were prepared at moulding water content (MWC) of -2, 0, +2 and +4 % relative to optimum moisture content (OMC) and compacted with the British Standard light (BSL) energy. Cementation reagent was allowed to percolate the compacted specimens until partial saturation was achieved. Results show that UCS values increased with rise in B.
coagulans suspension density. UCS of natural soil prepared at -2 % OMC decreased from 278.3 kN/m2 to 141.45 kN/m2 at +4 % OMC. Similar trend were recorded for specimens treated with varying B.
coagulans suspension densities when prepared at MWC of -2, 0, +2 and +4 % relative to OMC. Also, UCS values improved with rise in dry density. The UCS values of specimens prepared with B. coagulans suspension densities and compacted at MWC of -2, 0 and +2 OMC, respectively, satisfied the minimum requirement of 200 kN/m2 and can be apply as liner and cover materials in municipal solid waste containment system.
Impact of climate change on the rainfall pattern of Klip River catchment in Ladysmith, KwaZulu Natal, South Africa
Authors: Chabalala D T , Ndambuki J M , Salim R W , Rwanga S S
Published: November 2019

Rainfall trend analysis has been of major focus in the past century because of the attention given to climate change by the science and engineering community. According to some latest studies, rainfall is one of the main parameters in any catchment which plays a significant role in flood frequency, flood control as well as water resources planning and management. Ladysmith town in South Africa is flooded almost every year resulting in loss of lives as well as properties and businesses. Thus, this study aimed at determining the monthly and annual rainfall pattern in relation to climate change. The monthly, seasonal and annual rainfall trends for the period 1985 – 2018 were analyzed using Mann-Kendall test and Sen’s slope estimation. Results of this study indicated a variability in seasonal rainfall, with a rainfall increase during December and January of summer months whose Mann-Kendall test results were 1.88 and 0.73, and a major decrease showed in autumn months (March, April, and May) with Mann-Kendall test values of -2.76, -3.53 and -4.09. Thus, the overall results suggest a minor significant change for both Ladysmith and upstream of the Klip river catchment. Based on the analysis, it can be concluded that climate change has an impact on the rainfall spatial pattern of the study area. This correlates well with similar analysis carried out in other areas around the world.
Petroleum hydrocarbon contaminated groundwater remediation using 21st century technology: Baruwa community, Lagos State Nigeria as a case study
Authors: Ola S A , Fadugba O G , Adekoya J A , Babatola J O , Ajayi O O , Ojuri O O , Akinde S B
Published: November 2019

This research focused on geo-environmental site assessment and remediation of contaminated soil/groundwater. Baruwa community is the study site and it is located at Alimosho Local government area of Lagos state, Nigeria. About 350 hand dug wells for domestic water supply are in the community, all the wells are contaminated with petroleum product from leaking underground pipeline that transverse the community. Free hydrocarbon product thickness up to 0.72m was found on top of the groundwater in the hand dug wells. The main objective of the project was to take a hectare (100m x 100m) of the most contaminated area and remediate the groundwater to permissible level using the most up-to-date equipment and technology. Integrated Remediation Approach (IRA) was utilized; this involves physical and chemical method. The physical method involves the use of skimming-off technology that draws out the pure non-aqueous phase liquid (PNAPL) from the hand-dug wells. Chemical method adopted was in-situ chemical oxidation (ISCO), which involves injecting oxidizing agent (KMnO4) to the groundwater in the hand dug wells. Notable deplection in the values of TPH from a maximum of 500ppm to 20, 0, 25, 6, 6, 0.7 ppm for the six monitored wells during the 30 weeks of observation.
Environmental assessment of municipal solid waste (MSW) disposal options: A case study of Olushosun landfill, Lagos State
Authors: Balogun-Adeleye R M , Longe E O , Aiyesimoju K O
Published: November 2019

Landfills are known to be one of the anthropogenic sources of methane (CH4) and this gas is an important contributor to global warming. Aside the threat posed by methane, if properly managed, it could be harnessed as a source of energy. The efficient management of landfill generated CH4 gas would require the accurate prediction, monitoring and utilization of this useful source. Therefore, this study is focused on the life cycle assessment (LCA) of Olushosun landfill in Lagos metropolis. Environmental benefits between operation of landfills with and without gas recovery systems in Olushosun landfill were determined. LCA analysis showed greenhouse gas (GHG) emissions from the present waste disposal system was 3,029,151tons of carbon dioxide emissions (CO2). The adoption of sanitary landfill with gas recovery system is a preferred management route for solid waste disposal in Lagos metropolis due to CO2 emissions reduction of 1,725,761 tons. The results obtained also corroborate the use of LCA as a decision support tool in waste management system. It is therefore recommended that LCA should be implemented in developing countries to reduce long term environmental effects of waste management activities.
Dangerous organic chemicals identified in inhalable particulate matter air pollution
Authors: Etchie T O , Etchie A T , Sivanesan S , Adewuyi G O , Krishnamurthi K , Pillarisetti A , George K V , Rao P S
Published: November 2019

Inhalable particulate matter (PM10), comprising fine and thoracic coarse particulate matter (PM2.5 and PM10-2.5, respectively), is emitted from several sources. The sources includes construction and agricultural activities, transportation, industrial processes, power plants, wildfires, household solid cookfuels and suspensions or re-suspensions from unpaved roads, mining and natural sources. Previous studies, specifically from developed countries and China have shown that PM10 may contain several dangerous organic chemicals (DOCCs). However, very little is known about PM10 in developing countries. Therefore is study seeks to identify the DOCCs in airborne PM10 in Nagpur district, India. We collected 24-hr ambient PM10 samples from urban, peri-urban and rural areas of the district during wintertime (January, 2013). The DOCCs in the PM10 were identified by gas chromatography-mass spectrometry. The results revealed that polycyclic aromatic hydrocarbons (PAHs), chlorinated hydrocarbons, dioxins, furans, phthalate esters, aldehydes, ketones, phenols and organic acids are major DOCCs in the PM10. Quantitative analysis of thirteen individual PAHs in the PM10 revealed concentrations that greatly exceeded health-based guideline. This suggests that prolong inhalation of such PM10 may pose adverse risk to health of the population.
Health implications of economic growth: the role of air pollution
Authors: Afolabi A , Urhie E , Ogunbiyi T , Ogundiran F , Afolabi A
Published: November 2019

Economic growth comes with benefit and cost. The benefits include improved standard of living, better health care facilities and longer years of living as well as better chances of attaining higher education. There are also costs to economic growth. Economic growth entails increasing productive and consumption activities that can lead to health challenges, increase in income inequality, depletion of natural resources and increased environmental pollution, especially air pollution. Air pollution also indirectly affects income generation and savings for households. It places additional cost burden on governments. This paper thus evaluated the relationship that exists between economic growth and health performance in Nigeria vis-à-vis air pollution. The study used the PROCESS software to estimate the direct, indirect and total effects of economic growth on the health performance in Nigeria. The study found a direct and positive relationship exist between gross domestic product and life expectancy, variables used to capture both economic growth and health performance in Nigeria. It further found that the relationship could be indirectly effected with the use of a transmission mechanism, in this case-air pollution, to show that economic growth may not always lead to better health outcomes.