Suitability of Waste Paper Ash Blended with Lime to Improve the Strength of Expansive Sub-grade Soil

Expansive soils have the tendency to behave volume change during wetting and drying conditions which causes significant damage to structures such as buildings and pavements. This behavior of the soil cause large uplift pressure, differential settlement, and upheaval of structures built on them. Avoiding these types of unsuitable soils is mostly impractical. Hence, the aim of the study is to investigate the suitability of waste paper ash blended with lime to improve the strength of expansive sub-grade soil to be used as sub-grade materials. The research design followed the experimental type of study which began by collecting samples. In this study moisture content, Atterberg limits, particle size distribution, soil classification, free swell index, linear shrinkage, specific gravity, compaction (moisture-density relationship) tests, CBR and CBR swell were determined. The sampling technique used for this research was a purposive sampling which is non– probability method. Two expansive soil samples were taken for the study by observation and free swell index tests at a depth of 1.5 m-2 m to remove organic matters. The data processing and analyzing were conducted by using both descriptive and analytical methods. Laboratory test result of waste paper ash shows that specific gravity, liquid limit, plastic limit, plastic index and optimum moisture content were 1.67, 50.8%, 43.7%, 7.1% and 50.1%, respectively. The laboratory test results fulfilled the requirements of class-C fly ash according to ASTM C-618. JIT soil sample has plastic index 39 %, free swell index 88.12 %, linear shrinkage 17.73% and CBR value 2.33%. In addition, the MAR soil sample has plastic index 41.8 %, free swell index 96.83%, linear shrinkage 20.07% and CBR value 1.95%. Since both soil samples were found with high degree of expansion, stabilization was made by mix-ratio of (0, 2%HL+12%WPA, 4%HL+10%WPA, 6%HL+8%WPA, 8%HL+6WPA). As the content of hydrated lime increases and WPA decreases in WPA: HL mix-ratios, LL, PI, MDD, FSI, CBR swell decreased whereas PL, OMC, CBR are increased. All the laboratory test results were compared with standard specifications. It was recommended to investigate the effect of additional curing time and aging effect of soil stabilized by WPA. Additional parameter like unconfined compressive strength, PH value test, volumetric shrinkage and mineralogical tests should also be performed to have more realistic test result

Analysis Factors Affecting Success Of Public Projects Implementation :A Study On Sebeta City, Oromia Regional State

The purpose of this study is to analyze factors affecting success of public projects implementation the case of Sebeta City, Oromia Regional State. The study used descriptive and explanatory research design. The study targeted a sample of 211 from a target population of 450 located in the study area. Simple random and purposive non random sampling technique was utilized in selecting the respondents for the study. Primary and secondary data was collected from the study respondents using questionnaires and interview which were self-administered. Data was analyzed descriptively and presented through figures, tables, percentages, bar charts, pie charts and tabulation to show differences in frequencies. Statistical Package for Social Sciences (SPSS) version 20.0 was used to aid in coding, entry and analysis of quantitative data obtained from the closed ended questions. Binary logistic regression was used to Analysis the major Factors Affecting Success of Public Projects Implementation. The study revealed out that the major Factors Affecting Success of Public Projects Implementation was poor project initiation, followed by poor project planning/design system, poor project monitoring, and evaluation and controlling system, poor communication and improper project closure. Therefore considering the importance the study recommends the organization to focus on Project identification, feasibility study, appraisal and selection, proper project planning tools and priciples,recurrent monitoring, evaluation and control against standard and performance , proper procurement and contract administration, follow effective communication and proper project closure techniques during project implementation. This will ensure that a project success implementation measurement n such as client satisfaction, cost, time and goal can be achieived in the study area.

AISI/DOE Technology Roadmap Program: Development of Appropriate Resistance Spot Welding Practice for Transformation-Hardened Steels

This report describes work accomplished in the project, titled ''Development of Appropriate Resistance Spot Welding Practice for Transformation-Hardened Steels.'' The Phase 1 of the program involved development of in-situ temper diagrams for two gauges of representative dual-phase and martensitic grades of steels. The results showed that tempering is an effective way of reducing hold-time sensitivity (HTS) in hardenable high-strength sheet steels. In Phase 2, post-weld cooling rate techniques, incorporating tempering, were evaluated to reduce HTS for the same four steels. Three alternative methods, viz., post-heating, downsloping, and spike tempering, for HTS reduction were investigated. Downsloping was selected for detailed additional study, as it appeared to be the most promising of the cooling rate control methods. The downsloping maps for each of the candidate steels were used to locate the conditions necessary for the peak response. Three specific downslope conditions (at a fix ed final current for each material, timed for a zero-, medium-, and full-softening response) were chosen for further metallurgical and mechanical testing. Representative samples, were inspected metallographically, examining both local hardness variations and microstructures. The resulting downslope diagrams were found to consist largely of a C-curve. The softening observed in these curves, however, was not supported by subsequent metallography, which showed that all welds made, regardless of material and downslope condition, were essentially martensitic. CCT/TTT diagrams, generated based on microstructural modeling done at Oak Ridge National Laboratories, showed that minimum downslope times of 2 and 10 s for the martensitic and dual-phase grades of steels, respectively, were required to avoid martensite formation. These times, however, were beyond those examined in this study. These results show that downsloping is not an effective means of reducing HTS for production resistance spot welding (RSW). The necessary downslope times (2-10s) are prohibited by the welding rates currently used today (up to 60 welds/s). Based on the observations made in this study, spike tempering appears to be the best compromise of microstructural improvement and short cycle time. It is recommended that future work be focused on exploring the robustness of this approach, and its applicability for a wider range of steels

Significance of the Sung wares in the world porcelain

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Impact of land-use dynamics and climate change scenarios on Groundwater recharge in the case of Anger watershed, Ethiopia

An assessment of land use dynamics and climate variability impacts on hydrological processes is vital and a prerequisite for effective water resources management. This study aimed to quantify the effect of land-use changes and long-term climate variability on the Anger watershed's annual groundwater recharge, which covers a total drainage area of 7717 km2. The WetSpass (Water and Energy Transfer between Soil, Plants, and Atmosphere under quasi-Steady State) model was used to investigate the impact of land cover and climate variability on groundwater. The Mann–Kendall (MK) test was used to analyze the spatial variations and temporal trends of the climate variables in the watershed. Input data for the model, such as land use, hydro-meteorological data, soil texture, topography, and groundwater elevation parameters, were prepared in the form of gridded maps with a 30 m resolution. The model results indicate that land-use change and climate variability considerably impact distributed groundwater recharges. Groundwater recharge decreased with land use in 2000 and 2019, respectively, as compared to baseline land usage (1985). The study also demonstrates how the anticipated future combination of less precipitation and higher temperatures has a detrimental effect on the watershed's annual average groundwater recharge. Future rising temperatures and reduced precipitation are projected to result in an average annual groundwater recharge showing significant decreases in 2050, 2080, and 2110, respectively, according to scenario-based models. The result has provided valuable information on the management and response of groundwater recharge to climate and land-use changes, particularly for the Anger watershed and for the total country as well