-
Experimental Study of Strength Development in Black Cotton Soil and Granular Material Reinforced with Geogrid and Non-Woven Geotextile
Kevin Maraka Ndiema,
Yin Zihong,
Raymond Leiren Lekalpure,
Mouhamed Bayane Bouraima,
Clement Kiprotich Kiptum
Issue:
Volume 11, Issue 1, January 2022
Pages:
1-8
Received:
18 October 2021
Accepted:
27 December 2021
Published:
8 January 2022
Abstract: Reinforcement of flexible pavements using geosynthetics is gaining widespread application. However, there is inadequate understanding of strength development for non-woven geotextile and geogrid as reinforcement in Black Cotton Soil (BCS) and granular material in relation to cement stabilization method. Therefore, this paper presents experimental study to investigate strength development for BCS and granular material reinforced with geogrid and non-woven geotextile using California Bearing Ratio approach. The categories of samples tested were; neat, reinforced and cement stabilized. All samples were tested after 4 days’ soak. Placement of reinforcement material in BCS was done at 0.3H and 0.6H for single layer reinforcement while for double layer reinforcement, it was done at both 0.3H and 0.6H. In granular soil, single layer reinforcement condition only was considered at 0.2H, 0.4H and 0.6H. Cement stabilization for both BCS and granular soil was done by the following percentages of cement increment; 1%, 2%, 3% and 4%. From the study, the strength improvement considering single layer reinforcement by geogrid and non-woven geotextile in BCS was 37.5% and 45% respectively. In granular material, CBR strength increased by 21% and 14% due to geogrid and non-woven geotextile respectively. Percentage increase in CBR of reinforced BCS corresponded to that of over >1% cement stabilization. To further enhance decision making between these strength development alternatives, it is recommended to advance it to cost analysis.
Abstract: Reinforcement of flexible pavements using geosynthetics is gaining widespread application. However, there is inadequate understanding of strength development for non-woven geotextile and geogrid as reinforcement in Black Cotton Soil (BCS) and granular material in relation to cement stabilization method. Therefore, this paper presents experimental s...
Show More
-
Synthesis and Properties of Melamine Modified Urea Formaldehyde Resin for Impregnation Under New Process
Zhiyong Zheng,
Huaihao Chen,
Kaijie Zheng,
Qi Li,
An Mao
Issue:
Volume 11, Issue 1, January 2022
Pages:
9-14
Received:
30 December 2021
Accepted:
11 January 2022
Published:
25 January 2022
Abstract: In this paper, the basic properties of UF and UMF resins for impregnation under conventional and new processes were compared, and their chemical structures were characterized by 13C NMR. The effects of synthetic process and melamine addition on the bonding strength and formaldehyde emission of UF and UMF resins were studied. The resin synthesized by the new process has higher linear and methylene ether bond content, relatively lower methylene content, longer curing time and storage life and lower free formaldehyde content than the conventional resin; When melamine was added at the initial stage of UF resin synthesis reaction, it did not significantly change the total amount of methylene ether and hydroxymethyl in the resin system, but the content of class I hydroxymethyl increased and the content of class II hydroxymethyl decreased. The reason may be that the added melamine and urea react not only with the remaining formaldehyde in the system, but also with the formaldehyde removed from hydroxymethyl due to dehydroxylation reaction, Hydroxymethylmelamine and monobasic substituted urea are produced. At this time, about 50% of melamine still exists in UMF resin in the form of free or low hydroxymethylate, and does not participate in the formation of the main structure of the resin. Melamine was added in the early stage of the reaction. The modified resin bonded plywood has high bonding strength and low formaldehyde emission.
Abstract: In this paper, the basic properties of UF and UMF resins for impregnation under conventional and new processes were compared, and their chemical structures were characterized by 13C NMR. The effects of synthetic process and melamine addition on the bonding strength and formaldehyde emission of UF and UMF resins were studied. The resin synthesized b...
Show More
-
Application of Graphene Oxide in Composite Geothermal Floor
Zhiyong Zheng,
Yuanting Zhu,
Kaisen Zheng,
Qi Li,
An Mao
Issue:
Volume 11, Issue 1, January 2022
Pages:
15-20
Received:
30 December 2021
Accepted:
14 January 2022
Published:
25 January 2022
Abstract: With the rapid development of China's solid wood composite flooring industry, the market of solid wood composite geothermal flooring is gradually huge. The adhesives used in traditional solid wood composite geothermal flooring are mainly urea formaldehyde resin and phenolic resin. Its bonded wood-based panel has the problems of formaldehyde emission and poor waterproof. With the enhancement of people's awareness of safety and environmental protection, the problem of formaldehyde has attracted more and more attention. Looking for various formaldehyde free adhesives that can replace urea formaldehyde resin has become a research hotspot. Graphene oxide is a new carbon material with excellent properties, which has high specific surface area and rich functional groups on the surface. In this study, powdered oxygraphene material and isocyanate resin were mixed in different proportions to press the three-layer solid wood composite floor substrate, and the bonding strength and thermal conductivity were tested to investigate the effect of graphene oxide powder on the bonding and thermal conductivity of isocyanate resin. The experimental results show that the viscosity of the resin system increases with the increase of the amount of graphene oxide powder; Graphene oxide powder with mesh number of 250 can significantly enhance the bonding strength of isocyanate, But when the amount is too large (10%) on the contrary, the bonding strength decreases. Graphene oxide powder with mesh number of 50 does not significantly enhance the bonding strength; adding graphene oxide powder can improve the thermal conductivity of the floor. With the increase of the proportion of graphene oxide, the thermal conductivity, thermal conductivity and electrothermal conversion rate of the floor are significantly improved, but graphene oxide with mesh number of 50 is not as good as graphite oxide with mesh number of 250 Alkene increased significantly. The addition of an appropriate amount of graphene oxide fine powder reduces the infiltration of resin into wood, enhances the bonding performance and thermal conductivity, provides a new possible way for the application of graphene oxide material and isocyanate in the substrate of solid wood composite floor, and provides a certain practical basis for the manufacturing process and application technology development of thermal conductive floor and geothermal floor.
Abstract: With the rapid development of China's solid wood composite flooring industry, the market of solid wood composite geothermal flooring is gradually huge. The adhesives used in traditional solid wood composite geothermal flooring are mainly urea formaldehyde resin and phenolic resin. Its bonded wood-based panel has the problems of formaldehyde emissio...
Show More
-
Risk Management of Implementation of Reagentless Treatment of Acid Mine Water
Zobnin Boris Borisovich,
Kochetkov Vitaly Victorovich,
Shokurov Denis Sergeyevich,
Korolev Oleg Anatolevich
Issue:
Volume 11, Issue 1, January 2022
Pages:
21-28
Received:
15 January 2022
Accepted:
4 February 2022
Published:
16 February 2022
Abstract: The task of managing the risk of introducing reagentless treatment of acid mine water is considered. The task is solved, first of all, for natural technological complexes formed by coal and copper-zinc-pyrite mines transferred to "wet" preservation due to unprofitability. To solve the problem, a mobile technological complex operating in a flow-through mode is used. The solution of the problem is based on a system decomposition of the object, tasks and research criteria. The object of the analysis are large volumes of heterogeneous flows of mine water arriving for treatment. The set task is a multi-criteria one. Multi-agent modeling integrating several applications interacting by means of input and output data flows is used for the system design. Decomposition of the set task on the basis of a joint study of mine water properties and treatment technology on a laboratory bench, on which it is possible to reproduce the minimum required set of treatment operations and water conditioning is performed. The structure of the system integrating the concept of safety and the concept of extraction of high value products from mine water is offered. Results of X-ray phase analysis of sediments obtained after cavitation treatment of mine water are presented.
Abstract: The task of managing the risk of introducing reagentless treatment of acid mine water is considered. The task is solved, first of all, for natural technological complexes formed by coal and copper-zinc-pyrite mines transferred to "wet" preservation due to unprofitability. To solve the problem, a mobile technological complex operating in a flow-thro...
Show More
-
Contribution to the Study of the Thermal, Rheological and Morphological Properties of Biocomposites Based on Typha/PP
Babacar Niang,
Abdou Karim Farota,
Abdoul Karim Mbodji,
Nicola Schiavone,
Haroutioun Askanian,
Vincent Verney,
Diène Ndiaye,
Abdoulaye Bouya Diop,
Bouya Diop
Issue:
Volume 11, Issue 1, January 2022
Pages:
29-36
Received:
23 December 2021
Accepted:
11 January 2022
Published:
16 February 2022
Abstract: Biocomposites based on polypropylene (PP) and typha fibre were prepared using a twin-screw extruder and different characterisation techniques, namely thermal, mechanical, rheological and morphological analysis, to evaluate the effects of typha stem powder on the final properties of the biomaterials. The rheological characterisation showed that the G' and G" values of pure PP and biocomposites increase with the rate of reinforcement and are related to agglomeration phenomena of Typha fibres which reduce the sliding or flow between them inside the biocomposite. The viscosity of the composites is strongly influenced by the shear rate. Shear thinning behaviour of the melt was observed. The results of the mechanical tests show an increase in tensile young's modulus up to 45% and an increase in tensile strength up to a critical value of 25% for typha stems, which can be attributed to the good interfacial adhesion between the matrix and the filler. Differential Scanning Calorimetry (DSC) measurements indicate the presence of crystalline phases and a slight difference of about 3°C between the melting temperatures. Typha acts as a nucleating agent. Micrographs show the diffuse aspect of the fibre distribution in the matrix. The good wettability of typha fibres by polypropylene contributes to the reduction of microcavities, which has a positive effect on the mechanical properties up to a certain level of reinforcement. Finally, the thermogravimetric analysis shows that typha fibre decreases the thermal stability of the biomaterials.
Abstract: Biocomposites based on polypropylene (PP) and typha fibre were prepared using a twin-screw extruder and different characterisation techniques, namely thermal, mechanical, rheological and morphological analysis, to evaluate the effects of typha stem powder on the final properties of the biomaterials. The rheological characterisation showed that the ...
Show More
-
Interactive Virtual Scanning Electron Microscope Inspired by 3D Game-Design
Pnina Ari-Gur,
Igor Lapsker,
Tyler William Bayne,
Eric Allen Pietrowicz,
Peter Thannhauser,
Spencer Hoin,
Hermanu Joko Nugroho
Issue:
Volume 11, Issue 1, January 2022
Pages:
37-41
Received:
6 January 2022
Accepted:
15 February 2022
Published:
25 February 2022
Abstract: The scanning electron microscope (SEM) has evolved to become an indispensable tool for research and education in engineering, physics, nanotechnology, geosciences, materials science, biological sciences and other fields. However, training on a physical SEM is costly, time consuming, and often unavailable in economically disadvantaged areas. Advances in computer technology have made interactive three-dimensional (3D) virtual laboratory an effective tool for training in medicine and many engineering and technology fields. In the current work, in order to provide cost-effective hands-on training, a virtual 3D SEM was developed using the game development engine Unity 3D. It contains realistic 3D models of the physical components, created using 3ds Max®, a software for 3D modeling and rendering. The components are manipulated with scripts programmed using C# and JavaScript and then paired with the corresponding model. Users may view and operate the virtual instrument, save images for further analysis, and write a report. The developed virtual SEM was tested on diverse groups of users at multiple institutions, each divided to treatment and control groups. Feedback from these tests was collected and used for improvements in the overall quality of the simulated experience. In addition, users reported the experience of training on the virtual SEM as enjoyable.
Abstract: The scanning electron microscope (SEM) has evolved to become an indispensable tool for research and education in engineering, physics, nanotechnology, geosciences, materials science, biological sciences and other fields. However, training on a physical SEM is costly, time consuming, and often unavailable in economically disadvantaged areas. Advance...
Show More
