176,947 research outputs found

    The factors influencing municipal solid waste generation in bauchi town, Nigeria

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    This study investigated the factors influencing municipal solid waste generation (MSWG) in Bauchi town, the administrative headquarters of Bauchi state, Nigeria. The study used quantitative method, while experiments and questionnaire surveys, were used as the major instruments for data collection. Data on solid waste generation and the socioeconomic attributes of residents from 400 households were collected from residential zones within Bauchi town, the study area. Descriptive statistics, Correlations and Standard Multiple Regressions (SMR) were computed for data analysis using SPSS 2.2 software. Twelve (12) socioeconomic factors were computed in SMR to determine the significant factors of MSWG in the study. The results showed that five factors, namely: household size, income, education, house head age and occupation have exerted significant influence on MSWG in the study area. The results also showed that F (5:362) = 84.058 at p ≤ 0.01 and adjusted R² = 0.531; which indicated that the factors in the SMR model have sufficiently explained the variance in MSWG in Bauchi town. The study concluded that the five significant predictor factors have adequately explained the variance of MSWG in the study area. Therefore, the factors have implications for planning of effective waste management system in Bauchi town, Nigeria

    The effect of chemical treatment, fibre length, fibre content and injection moulding parameters to uv irradiation resistance of oil palm fibre reinforced composites

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    There are many types of polymer used in engineering materials expose to UV irradiation, such as automotive parts (car body, bumper, dashboard etc.) which can cause material degradation. Some polymers are used in pure polymer and some of them in composite material. This study has investigated the composite material degradation. In this study, polypropylene was used as a matrix of the composite material samples, while oil palm fibre as reinforcement. The effect of the fibre length, fibre content, fibre treatment, coupling agent and injection moulding parameter to ultraviolet (UV) light resistance of this composite and also the optimum setting of them were investigated. The UV resistance was examined via the change of mechanical properties after UV exposured in the UV accelerated weathering tester. The Linear regression models were generated for tensile strength, strain at maximum stress, break stress, break strain and Charpy Impact strength based on six different UV exposure time i.e.: 0, 96, 336, 504, 1008, and 1512 hours. The significance of the regression models were tested by Analysis Of Variance (ANOVA) and verified by two expose time i.e: 168 and 672 hours. This study found that all of the mechanical properties decrease after UV irradiated. The largest property decrease was break strain of the samples, which was decrease in the range 44.54% to 79.21% after 1512 hours UV irradiated. The lowest decrease was break stress in the range 27.38 % to 63.82%. It was also found in this study that fibre content, and UV irradiation time, significantly affect all properties. Coupling agent and alkali treatment significantly affect all properties except strain at maximum stress. Whereas fibre length and injection moulding parameter only significantly affect the Impact strength of the specimens. All of the regression models are significant which are signed by the p value of each of regression models were lower than 0.05. The equation for predicting the lifetime of UV exposed of oil palm fibre reinforced composite have been generated. The lifetime UV irradiated specimen can be predicted using this equation

    One machine, one minute, three billion tetrahedra

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    This paper presents a new scalable parallelization scheme to generate the 3D Delaunay triangulation of a given set of points. Our first contribution is an efficient serial implementation of the incremental Delaunay insertion algorithm. A simple dedicated data structure, an efficient sorting of the points and the optimization of the insertion algorithm have permitted to accelerate reference implementations by a factor three. Our second contribution is a multi-threaded version of the Delaunay kernel that is able to concurrently insert vertices. Moore curve coordinates are used to partition the point set, avoiding heavy synchronization overheads. Conflicts are managed by modifying the partitions with a simple rescaling of the space-filling curve. The performances of our implementation have been measured on three different processors, an Intel core-i7, an Intel Xeon Phi and an AMD EPYC, on which we have been able to compute 3 billion tetrahedra in 53 seconds. This corresponds to a generation rate of over 55 million tetrahedra per second. We finally show how this very efficient parallel Delaunay triangulation can be integrated in a Delaunay refinement mesh generator which takes as input the triangulated surface boundary of the volume to mesh

    Load-Balancing for Parallel Delaunay Triangulations

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    Computing the Delaunay triangulation (DT) of a given point set in RD\mathbb{R}^D is one of the fundamental operations in computational geometry. Recently, Funke and Sanders (2017) presented a divide-and-conquer DT algorithm that merges two partial triangulations by re-triangulating a small subset of their vertices - the border vertices - and combining the three triangulations efficiently via parallel hash table lookups. The input point division should therefore yield roughly equal-sized partitions for good load-balancing and also result in a small number of border vertices for fast merging. In this paper, we present a novel divide-step based on partitioning the triangulation of a small sample of the input points. In experiments on synthetic and real-world data sets, we achieve nearly perfectly balanced partitions and small border triangulations. This almost cuts running time in half compared to non-data-sensitive division schemes on inputs exhibiting an exploitable underlying structure.Comment: Short version submitted to EuroPar 201
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