Stabilization of Johor Peat Soil using Sugarcane Bagasse Ash (SCBA)

Peat soil have been categorized as a problematic organic soil, because they have a high settlement rate when placed any structure on it. Therefore, the peat soil must first be stabilized using cement before it can be used. However, massive use of cement can lead to environmental pollution. Therefore, this study intends to use sugar cane bagasse ash as a substitute for cement in peat soil stabilization. The mix ratio of 5% to 20% was used to find the optimal mix ratio. Various tests were carried out on samples such as basic properties tests, Unconfined Compressive Strength (UCS) and Scanning Electron Microscope (SEM). After all the tests, the 5% replacement SCBA mix ratio gave the highest unconfined compressive strength if compared to the other mixtures ratio. Therefore, it is selected as the optimum mix ratio. The soil strength achieved by the SCBA 5% replacement ratio was found to be higher than cement stabilization alone due to the presence of secondary pozzolan reactions. The microstructure result from the SEM test had shown that the 5% replacement SCBA mix ratio filled in the hollow left by the peat soil. Hence, able to improve its soil structure and thus increasing its strength.

Strategic workforce planning: from closing skills gaps to optimizing talent

Purpose The purpose of this APQC (American Productivity and Quality Center) research study is to understand which strategic workforce planning approaches are currently in use; whether these approaches are meeting business needs; and what workforce planning challenges organizations are facing today. Design/methodology/approach This study involved survey research with 236 valid respondents representing organizations from a wide range of industries, regions, workforce sizes and revenues. American productivity and quality center (APQC) identified 46 “best-in-class” workforce planners from among these organizations based on their consistent achievement of superior results from workforce planning. Findings Best-in-class workforce planners are doing more than closing skills gaps and reducing skills surpluses. They are optimizing talent. Leveraging technology, varied work arrangements and employee development, they assemble the optimal mix of talent to achieve business goals. Originality/value The findings provide insight into how best-in-class workforce planners build a strong foundation for effective workforce planning through the distinctive ways they use process, people, technology and time. Organizations that adopt the practices and approaches of best-in-class workforce planners can drive improvements in their own workforce planning process.

Effects of active mineral admixture on mechanical properties and durability of concrete

the purpose of this study is to figure out the effects of the active mineral admixture on the mechanical performance and the durability of the concrete. In this paper, the orthogonal test is adopted to study the effects of the Metakaolin, the ultra-fine fly ash, and the silica fume on the compressive strength and the splitting tensile strength of the concrete at various curing ages, and to further determine the optimal mix ratio. After that, the ordinary concrete is taken as the control group, the Na2SO4 solution and the MgSO4+NaCl solution are taken as the corrosive medium, and the dry-wet alternation method is used to make comparison and micro-analysis on the durability degradation processes of both the admixture concrete with optimal mix ratio and the ordinary concrete in the two solutions as mentioned above. The results show that: as for the concrete mechanical performance, the Metakaolin shows the biggest positive effects on the concrete cured for 7d-14d, while the silica fume affects the concrete with 28d curing age most. The mechanical performance of concretes at various curing ages reach their optimal levels under the conditions of being added with 10% Metakaolin, 15% ultra-fine fly ash, and 3% silica fume. For the concrete durability, the way of adding mineral admixture could greatly improve the concrete capability in resisting the SO4 2- corrosion. However the complex ion has destructive effect on the mineral admixture concrete. Compared with the ordinary concrete, it shows the most significant growth of corrosion product M-S-H, faster reduction of mechanical performance, and loose and porous micro-structure.

Mechanical Properties of Granite-Gravel Porous Concrete

The need for porous concrete has become increased due its ability to control surface water, increase the rate of recharging groundwater, and reduce pollution of the ecosystem. Granite is a coarse aggregate that is quite expensive when compared with gravel in Nigeria. Therefore, this research is aimed at optimizing blended granite and gravel in the production of porous concrete. Samples of blended granite-gravel porous concrete of varying mix proportions were produced using cement to aggregate mix ratio of 1:4. The samples were tested for their porosity, workability and compressive strengths. The data collected were analyzed with the aid of Design Expert 10.0. It was observed that the optimal combination for the granite-gravel blended porous concrete is 12% granite, 88% gravel, and a water-cement ratio of 0.66%. This combination gave a porous concrete with a compressive strength of 48.4 N/mm2, percentage porosity of 6% and a compacting factor of 0.91. These values when compared to that of the control specimen revealed that the optimal mix gave a porous concrete with higher porosity, higher workability and a better compressive strength.

A Method for the Design of Concrete with Combined Steel and Basalt Fiber

Combining different fiber types may improve the mechanical properties of fiber reinforced concrete. The present study is focused on investigating hybrid fiber reinforced concrete (HFRC) with steel and basalt fiber. Mechanical properties of fiber reinforced fine-grained concrete are investigated. The results demonstrate that using optimal steel and basalt fiber reinforcement ratios avoids concrete mixtures’ segregation and improves their homogeneity. Concrete with hybrid steel and basalt fiber reinforcement has higher strength. Effective methodology for proper design of HFRC compositions was proposed. It is based on the mathematical experiments planning method. The proposed method enables optimal mix proportioning of high-strength fine-grained concrete with hybrid steel and basalt fiber reinforcement.

Optimal Mix Ratios of Green Building Materials and Construction Cost Control

Green concrete wall-building composite materials (namely GBMs, green building materials for short) have superior mechanical properties and good durability, thus they are now a high-profile topic in relevant research field. However, due to the existence of risk factors such as the high initial cost, and unclear policy direction, the promotion of GBMs has been greatly limited. In this context, it is a necessary work to study the cost control of construction projects, and figure out the relationship between the saving of building operating cost and the increase of initial construction cost. For this purpose, this study experimented on the optimal mix ratios of GBMs to control the construction budget of engineering projects. At first, this paper modeled the strain-hardening and steady-state cracking of GBMs, and constrained the models based on the bridging rule, the energy criterion, and the strength criterion. Then, this paper constructed a fractal model for the dense effect of powder particles in the aggregates of the GBMs, and analyzed its fractal features; after that, this paper designed the mix ratios of GBMs and experimented on the mechanical properties; at last, this paper constructed a production cost-use benefit model of the GBMs, completed the construction budget control of the engineering project, and gave experimental results of the performance of GBMs and the use cost calculation and analysis results.

Elaboración de una Crema Cosmética a Partir de Extractos de Coriandrum Sativum

Coriandrum sativum L. es una hierba aromática muy empleada como condimento. Presenta gran variedad de metabolitos con diversas propiedades, incluyendo elevada actividad antioxidante. El objetivo del trabajo fue diseñar una crema a partir de extracto hidroalcohólico obtenido de las hojas de Coriandrum sativum L (cilantro) con fines cosméticos. Se partió del estudio de algunos parámetros fisicoquímicos del material vegetal incluyendo la cuantificación del contenido de grasa por resonancia magnética nuclear de baja resolución. Mediante espectrofotometría UV, se valoró el contenido de fenoles totales y la capacidad antioxidante (DPPH) a diferentes extractos de las hojas y los tallos con etanol al 25, 50 y 75%. La mayor cantidad de fenoles totales y actividad antioxidante se obtuvo en el extracto hidroalcohólico (50%) de las hojas con valores de 21,867/0,275 mg/g de muestra seca y 56,68% de decoloración del DPPH. Se diseñó una crema (w/o) a partir del extracto hidroalcohólico de las hojas al 50%, con empleo del diseño de mezcla D-optimal de tres componentes con restricciones: cera de abeja, borato de sodio y agua. Las variables respuesta fueron pH y el área de extensibilidad. Ambas variables presentaron modelos cuadráticos obteniendo una significación p < 0,0002, pérdida de ajuste p>0,05 y R2 ajustado cercano a 1. Finalmente, la formulación obtenida fue la combinación cera de abeja 11,3- borato de sodio- 1 y agua 14,5 con un pH 6,8, extensibilidad 23,7 y 100% deseabilidad. De esta manera se desarrolló una preparación cosmética (crema) de uso tópico natural con actividad antioxidante, empleando herramientas estadísticas. Palabra clave: Coriandro sativum, fenoles totales, capacidad antioxidante, diseño D-optimal. Abstract Coriandrum sativum L. is an aromatic herb widely used as a condiment. It presents a variety of metabolites with various properties, such as antioxidant activity. The objective of this work was to design a cream from the hydroalcoholic extract obtained from the leaves of Coriandrum sativum L (Culantro) for cosmetic purposes. A physicochemical parameters study was carried out on the raw drug, including a fat content determination by Low-Resolution Nuclear Magnetic Resonance. The antioxidant capacity (DPPH) and total phenols content were valued in different leaves and stems extracts with 20, 50, and 75% of ethanol through UV spectrophotometry. The highest amount of total phenols was obtained in the hydroalcoholic extract (50%) of leaves with 21,867 / 0,275 mg/g from a dry sample and 56.68% DPPH discoloration. A cosmetic cream was designed starting from a 50% hydroalcoholic leaves extract using a three components D-optimal mix design with restrictions: beeswax, sodium borate, and water. Extensibility, area, and pH were the response variables. Both variables presented quadratic and special cubic models obtaining values of p <0.05, adjustment lost p>0,05, and adjusted R2 near to 1. Experiment 1 shows 100% desirability. The analysis allowed a cosmetic preparation (cream) for natural topical use with antioxidant activity was developed using statistical tools. Keywords: Coriandrum sativum, total phenols, antioxidant capacity, D-optimal.

Strength Characteristics of Iron Tailings Blended Soil as a Road Base Material

Cement and ionic curing agent were blended with iron tailings (ITS) and natural soil to prepare a new road base material. 7-d unconfined compressive strength (UCS) was selected as the evaluation index for determining the optimal mix ratio. The results reveal that the 7-d UCS always increases with the increase of cement content, and firstly increases with the increase of curing agent content and then tends to remain stable, exhibiting an increasing trend first and then dropping with the increase of ITS content. In lieu of this, the optimum ratio of iron tailings blended soil (ITBS) is determined as follows: ITS and soil are mixed in ratio of 50: 50, and cement and soil curing agent account for 5% and 2% of the total mass, respectively. The results of splitting strength and flexural-tensile strength tests show that these strengths of the ITBS always increase with the curing age, and firstly increases and then decreases with the increase in ITS content. XRD and SEM analyses show that the ratio of ITS to soil significantly influences the micro-pore structure of the blended soil. At an ITS to soil ratio of 50% : 50%, the combination of soil and ITS particles is the closest which results in the highest strength attainment.

Availability and Feasibility of Renewable Resources for Electricity Generation in the Arctic: The Cases of Longyearbyen, Maniitsoq and Kotzebue

Currently, the dominant energy source for electricity generation in the Arctic is diesel, which is well proven for Arctic conditions. However, diesel is expensive in the Arctic, often due to long and complicated fuel transportation routes, and so inhabitants of Arctic communities can face high electricity costs. This paper investigates whether renewable energy resources can be harvested in a feasible and cost-competitive manner. The paper highlights which renewable energy resources are generally available in the Arctic and analyzes how renewable resources, such as hydropower, wind, and photovoltaics, can be used. Furthermore, we present three specific case studies to provide in-depth insight. A simulation with different energy generation scenarios using different renewable energy sources and penetration levels was performed for each case. The results indicate that renewables can be a cost-competitive option and that the optimal mix of renewables varies for different communities. Stakeholders and experts from the case study communities were also interviewed and their responses indicated a general acceptance of renewables.

Sequential learning to accelerate discovery of alkali-activated binders

Alkali-activated binders (AAB) can provide a clean alternative to conventional cement in terms of CO2 emissions. However, as yet there are no sufficiently accurate material models to effectively predict the AAB properties, thus making optimal mix design highly costly and reducing the attractiveness of such binders. This work adopts sequential learning (SL) in high-dimensional material spaces (consisting of composition and processing data) to find AABs that exhibit desired properties. The SL approach combines machine learning models and feedback from real experiments. For this purpose, 131 data points were collected from different publications. The data sources are described in detail, and the differences between the binders are discussed. The sought-after target property is the compressive strength of the binders after 28 days. The success is benchmarked in terms of the number of experiments required to find materials with the desired strength. The influence of some constraints was systematically analyzed, e.g., the possibility to parallelize the experiments, the influence of the chosen algorithm and the size of the training data set. The results show the advantage of SL, i.e., the amount of data required can potentially be reduced by at least one order of magnitude compared to traditional machine learning models, while at the same time exploiting highly complex information. This brings applications in laboratory practice within reach.