Papers by Keyword: Review

Abstract: To maintain its competitiveness, the Indonesian CPO industry must apply lean techniques such as value stream mapping (VSM) that can be utilized to increase the process efficiency. While there have been several studies which attempted to apply VSM techniques to the CPO industry, the results of these studies have not been summarized and compared. This paper aims to summarize the findings of previous VSM studies in Indonesian CPO industry and provide the directions for future researches. In this study, the brief literature review is applied in which the relevant articles are reviewed according to the scope of study, approach or method, and types of identified wastes. Various types of wastes found from the initial stage (FFB reception) to the final stage (CPO storage). The average process cycle efficiency score indicates the requirements for improvement actions. Recommendations for future VSM researches include the scope of the process stages studied, process mapping for future condition, and the requirements of green and sustainability aspects.

Abstract: To prevent the excessive depletion of natural resources, sustainable development requires using alternate sustainable materials. Researchers in the field of advanced construction materials are increasingly paying attention to kenaf fibers as a "green" material because of their possible application in composites to advance sustainable development. However, there has been no attempt of scientometric analysis to investigate the comprehensive understanding of the present state of applications of kenaf fibers in reinforced concrete. The study aims to perform a bibliometric analysis of the existing kenaf fibers reinforced concrete literature and to provide a picture of the research status during the last ten years from 2013 to September 2022. There were 303 articles extracted from the Scopus database. The “VOSviewer” tool was employed to visualize the literature containing the most active scientific journals, countries, and highly used keywords in the field of fibers reinforced concrete. The outcomes showed that “Hybrid Composites”, “Impact Strength”, “Water Absorption”, “Scanning Electron Microscopy”, “Polypropylenes” and “Polymer Composite” have recently emerged as themes related to the applications of KFRC, and grabbed the interest of academics, may also offer future research opportunities. Additionally, according to the frequency of the keywords used, three important research domains associated with kenaf fibers within the concrete in the construction materials field have been identified, including “Mechanical Properties”, “Fiber Reinforced Plastics”, and “Tensile Strength”. Furthermore, the recent studies on the impact of kenaf fiber utilization on the structural performance of reinforced concrete are reviewed. Accordingly, the explanations related to research findings, suggestions for future studies have been provided on the incorporation of kenaf fibers reinforced concrete in civil engineering applications.

Abstract: Construction and demolition waste (CDW) is very high in quantity, 30% - 40% of total solid waste and their management is inadequate and lack the integration of sustainability concepts. This situation leads to severe environmental effects, which are mainly associated with the production of new building materials due to the low recovery rate. In fact some studies show that 5-10% of total energy consumption across the EU is related to the manufacture of construction products. For this reason, CDW is a priority for many policies globally. For several years, a growing trend towards more sustainable construction processes has been taking place with a focus on secondary raw materials with lower environmental impacts on the entire life cycle. For this reason, this paper intends to contribute to increasing knowledge in this field through a review article. The review has the aim to evaluate the research gap, strategies to reduce construction waste and to promote the recycled materials use for a circular economy in construction sector. The results of the study showed that interest in this field of research has grown strongly over the years: the most publications on the subject relate to the last five years. On the other hand, issues relating to the topic did not attract particular interest in the range 2010-2016, in fact the number of publications in this period did not exceed 4%. The research showed that Europe is among the communities most sensitive to the issue and it has clearly revealed that there are still many barriers and research gaps to be overcome on this issue and the study has tried to identify the main ones.

Abstract: Foamed cellular concrete (FCC) is a type of lightweight concrete. Traditionally, it has been used for insulation and void filling. However, in the last years, the possibility of obtaining high strength FCC has motivated the study of its structural use. The novelty and uniqueness of this article is to provide a review of the most important aspect of FCC including component materials, design and mix elaboration, physical properties and mainly, its mechanical behaviour. Also, in order to achieve a global understanding of the material and its characteristics, advances regarding its physical properties are collected: density, porosity, thermal, acoustic and water insulation, durability, fire resistance and drying shrinkage. Then mechanical properties such as elastic modulus, compressive, tensile, bending and shear behaviour, are analysed. The literature review also aims to evaluate the influence of using inert and active mineral additions, fibers and chemical additives to improve its mechanical and physical properties. Based on the work done, research needs have been identified: there are no prediction models for stress-strain behaviour with complete curves for FCC in compression nor in traction, the performed numerical modelling is scarce, use and effect of chemical additives is a not far studied, long-term tests are scarce or nil, the evaluation of resistance in different aggressive environments has not been sufficiently evaluated.

Abstract: With the continuous exploitation of most reservoirs in China, the proportion of heavy oil reservoirs increases, and the development difficulty is greater than that of conventional reservoirs. In view of the important subject of how to improve the recovery factor of heavy oil reservoir, the thermal recovery technology (hot water flooding, steam flooding, steam assisted gravity drainage SAGD and steam huff and puff) and cold recovery technology (chemical flooding, electromagnetic wave physical flooding and microbial flooding) used in the development of heavy oil reservoir are summarized. The principle of action is analyzed, and the main problems restricting heavy oil recovery are analyzed The main technologies of heavy oil recovery are introduced from the aspects of cold recovery and hot recovery. Based on the study of a large number of literatures, and according to the development trend of heavy oil development, suggestions and prospects for the future development direction are put forward.

Abstract: The manuscript reviews the additive manufacturing technology. The principle of operation of the most popular and new AM methods was discussed. the manuscript presents the possibility of skewing different materials for individual technologies. Additive manufacturing technologies have been described that can manufacture parts from polymers, metals, ceramics and composites.

Abstract: Laser cladding technology is widely used in the surface modification of parts due to its excellent properties such as high hardness, high wear resistance and corrosion resistance. Extends the life of these parts under normal use conditions, greatly reducing production costs. In this paper, the influence of different parameters such as laser cladding process parameters—laser power and scanning speed, and their interaction on the performance of mold cladding layer is discussed, and the future development direction of laser cladding technology in mold is prospected.

Abstract: The paper deals with the properties, quality and durability of the exposed concrete. The main part of this paper are characteristic of architectural (sometimes called visible or naked) concrete and the criterion of the quality evaluation of the performed work. This is mainly the colour balance of the subject area, the quantity and the size of the pores, the quality of the raw material and the surface structure. Achieving the quality of architectural concrete is considerably more technologically demanding compared with conventional concrete. This is reflected also in its cost. In conclusion, the problems of surface layers of architectural concrete are summarized. Especially environments can cause faster degradation, reducing the lifetime of the whole construction, but also pointing to one of the main problems in construction, which is technological discipline.

Abstract: The lithium-ion battery is widely and increasingly used in many portable electronic devices and high-power systems in the modern society. Currently, it is significant to develop excellent cathode materials to meet stringent standards for batteries. In this paper, recent developments were reviewed for several typical cathode materials with high voltages and good capacities. These cathode materials referred to LiCoO₂, LiNiO₂, LiMn₂O₄, LiMPO₄ (M=Fe, Mn, Co and Ni, et al), and their composites. The technical bottlenecks about the cathode material is required to be conquered. For instance, LiCoO₂ and LiNiO₂ have high coulombic capacity and good cycling characteristics, but are costly and exhibit poor thermal stability. Simultaneously, LiMn₂O₄ exhibit good thermal stability, high voltage and high rate capability, but have low capacity. Thus it is advantageous to produce a composite which shares the benefits of both materials. The composite cathode material is superior over any single electrode material because the former has more balanced performance, and therefore, is promising to manufacture the next generation of batteries.

Abstract: This chapter focuses on the manufacturing of polymer composites reinforced by synthetic fiber with emphasis to the resin transfer molding technique (RTM). Herein, different related topics to foundations, classification, constituents and technological applications of polymer composites are presented. The problems associated to reinforcement and matrix interface and the manufacturing techniques of polymer composites are discussed. The study confirms RTM technique as a highly efficient process as compared with other manufacturing techniques of polymer composites.