{"title":"Design, Realization and Characterization of a Wide-Angle Microwave Metasurface Absorber","authors":"F. Frezza","doi":"10.31031/rdms.2019.11.000770","DOIUrl":"https://doi.org/10.31031/rdms.2019.11.000770","url":null,"abstract":"In this article, we present a metamaterial absorber (MMA), and more specifically a metasurface based on a periodic structure consisting of double split-ring resonators (dSRR) which efficiently absorbs electromagnetic radiation for a wide range of incidence angles for both the transverse electric (TE) and the transverse magnetic (TM) polarizations. The proposed unit cell was designed employing a full 3-D electromagnetic solver based on the Finite Element Method (FEM). The unit cell consists of a square split-ring resonator and a thin metallic plate separated by a dielectric layer. Investigations of parameterization and optimization have shown that small modifications in the geometry of the resonator led to enhanced angular absorption. The numerical simulation stage was followed by design and fabrication of a prototype containing several unit cells. The measurements on the prototype show an absorbance peak larger than 84% and 58% for the incidence angles θ=0˚ and θ=70˚ respectively, at 9.73 GHz. The proposed MMA and its variations enable numerous applications such as defense systems, communication and stealth technologies.","PeriodicalId":20943,"journal":{"name":"Research & Development in Material Science","volume":"160 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77903427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effective and Ideal Separation Factors at Sublimation Refining of Sm, Eu, Tm, Yb","authors":"Кravchenko Ai","doi":"10.31031/RDMS.2019.11.000768","DOIUrl":"https://doi.org/10.31031/RDMS.2019.11.000768","url":null,"abstract":"It is shown that the application of ideal separation factor in calculations of hightemperature sublimation refining of Sm, Eu, Tm and Yb has confined character: in considered base-impurity systems a difference between effective (β) and ideal (βi) separation factors increases with deviation of βi from unity and can be very significant; the measurable difference (in limited of a one order) between β and ideal βi is observed at deviation of βi from unity not more than 2 orders. The discrepancies between the effective and ideal separation factors in evaporative refining processes (distillation and sublimation at low impurity content) are not associated with the chemical interaction of the components.","PeriodicalId":20943,"journal":{"name":"Research & Development in Material Science","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81595470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Computer-Aided Porous Materials Description Based on Morphological Spectra","authors":"J. Kulikowski","doi":"10.31031/RDMS.2019.11.000769","DOIUrl":"https://doi.org/10.31031/RDMS.2019.11.000769","url":null,"abstract":"Synthetic porous materials, e.g. based on polyamide, polyether sulfone, polyvinylpyrrolidone etc. compounds, have numerous and important medical applications. They are used as filtering membranes in hemodialysis [1], micro-capsules for cells or drugs encapsulation and delivery [2], scaffolds for biological tissue cultivation [3], etc. Usefulness of porous materials in medical applications directly depends on their biochemical and mechanical properties, in particular, on porosity characteristics. The last should thus be carefully controlled within a production process and kept stable for exploitation period. For this purpose, numerical parameters describing size and shape of pores as well as global material porosity characteristics (porosity factor, material’s permeability, multi-layer architecture of porous membranes etc.) have been proposed [4,5]. In fact, the parameters don’t describe the pores directly but their planar cross-sections visible in SEM (Scanning Electron Microscope) images. Moreover, such geometrical parameters like pore section’s spread, surface, length of contour etc. are by computer systems interpreted in a discrete geometry sense, not quite consistent with the widely known Euclidean geometry. The differences are particularly clear in case of small (consisting of several pixels) geometrical objects analysis.","PeriodicalId":20943,"journal":{"name":"Research & Development in Material Science","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80328411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Timplalexis, A. Dimara, S. Krinidis, D. Tzovaras
{"title":"Metabolic Rate and Clothing Estimation for Thermal Comfort Inference","authors":"C. Timplalexis, A. Dimara, S. Krinidis, D. Tzovaras","doi":"10.31031/rdms.2019.11.000767","DOIUrl":"https://doi.org/10.31031/rdms.2019.11.000767","url":null,"abstract":"Indoor thermal comfort modelling introduces a field of research closely related to the occupants’ well-being, attendance and cognitive performance [1]. The regulation of the thermal conditions is conducted trying to eliminate any negative effects on the occupants’ feeling or execution of activities [2]. Thermal comfort is defined as «the condition of mind in which satisfaction is expressed with the thermal environment» [3]. Two key parameters that have a strong impact on thermal comfort are metabolic rate (M) and clothing insulation (Icl). Those parameters are usually estimated according to certain tables provided by Ashrae [3]. In this work, M and Icl are predicted utilizing feedback provided by the building occupants regarding their thermal sensation, measured on the ASHRAE 7-point range (Table 1).","PeriodicalId":20943,"journal":{"name":"Research & Development in Material Science","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91551421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of Graphitic Nanomaterials on Thermal, Mechanical and Morphological Properties of Polypropylene Nanocomposites","authors":"C. Mahajan, Satyendra Mishra","doi":"10.31031/RDMS.2019.11.000766","DOIUrl":"https://doi.org/10.31031/RDMS.2019.11.000766","url":null,"abstract":"Graphitic nanomaterials such as GO, RGO and carbon nanotubes (CNT) have attracted great interest in recent years because of their various applications such as mechanical, thermal, optical, and electrical properties [1-6]. PP is one of the commercial importance polyolefins because of its cost-effectiveness as well as intrinsic properties of low density, high stiffness, good tensile strength and inertness toward acids, alkalis and solvents [7]. PP has also been used in a wide range of applications including packaging [8], textiles [9], automotive components [10,11], aerospace [12,13], home applications [14], construction [15,16] etc. as per say; therefore, the improvement in the properties of PP is further needed. Researchers around the world tried various nanofillers such as MMT [17], nTiO2 [18,19], nBaCO3 [20], CaCO3 [21], nano polystyrene [22], Tea Dust /GO [23], graphene [24,25] and CNT [26] to improve thermal and mechanical properties of PP matrix. Some of the researchers used functionalization of graphene using 4,4’-diphenylmethane diisocyanate (MDI) and stearic acid to improve thermal and mechanical properties of PP [24]. Ryu [27] have done the functionalization of GO by alkylamine, and studied the crystallization, mechanical and electrical properties of isotactic polypropylene nanocomposites. Polypropylene composites of alkylamine-modified GO were prepared through a melt blending technique using maleic anhydride-grafted PP as a compatibilizer. Significant improvements were observed in melt crystallization characteristics, mechanical and electrical properties upon loading alkyl amine-modified GO in PP due to strong interfacial interactions between the polymer and modified GO.","PeriodicalId":20943,"journal":{"name":"Research & Development in Material Science","volume":"88 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76293016","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shubham Mishra, A. Dubey, E. Prasad, S. Agarwal, Xunli Zhang
{"title":"Mechanical Characterization of Natural Fiber based Polymer Matrix Composite -A Review","authors":"Shubham Mishra, A. Dubey, E. Prasad, S. Agarwal, Xunli Zhang","doi":"10.31031/rdms.2019.11.000765","DOIUrl":"https://doi.org/10.31031/rdms.2019.11.000765","url":null,"abstract":"Polymer composites are primarily composed of matrix and reinforcement as glass fiber and carbon fiber. These types of fibers are known as synthetic or man-made fibers. These type of synthetic fibers based polymer composites have a certain drawback such as after being used these composites are not reusable and biodegradable. This is a major concern for environment, to counter this problem Natural Fiber (NF) has been introduced in polymer composites as reinforcement. Natural fibers are extracted from plants such as jute, cotton, flax, hemp, sisal, kenaf, pineapple, ramie, bamboo and banana as lingo cellulosic fibers. Classification of natural fibers is shown in Figure 1. Various natural fibers produced from plants have been shown in Figure 2. Natural fiber based composites are renewable, economical, completely or partially recyclable, and biodegradable. Their availability, renewability, less density and cost as well as reasonable mechanical properties make them a potential alternative of synthetic fibers [1]. Properties of selected natural fiber are as shown in Table 1 [2].","PeriodicalId":20943,"journal":{"name":"Research & Development in Material Science","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79573432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Reliability Studies Based on the Tensile Properties of the Polymer Nanocomposites","authors":"S. Mandal, D. Roy, N. Prasad, Xunli Zhang","doi":"10.31031/RDMS.2019.11.000764","DOIUrl":"https://doi.org/10.31031/RDMS.2019.11.000764","url":null,"abstract":"Polymer composites based on the high-performance thermoplastic polymers have many advantages and used for the various applications viz. bearings, brakes, clutches, gears, automation machinery in office, rollers and seals, pads of tank track, transmission belts along with many others [1-5]. The combination of superior thermo-mechanical properties causes poly (ether ketone) (PEEK) as a promising candidate for applications under chemical environment at high temperatures [6-10]. Poly (ether ketone) (PEK) is also semi crystalline polymer with glass transition temperature of 155 °C and melting point of 365 °C [11]. Poly (ether sulphone) (PES) is an amorphous polymer with a high Tg and can be classified as a thermally stable polymer. Among other interesting properties of PES, are good hydrolytic and thermo-oxidative stability, high rigidity and creep resistance. The high Tg of PES suggests the polymer as a suitable candidate for developing PEEK based blends [12,13]. Various studies have been carried out by different researchers on PEEK based composites [14-16]. However enormous scopes are still left to study in depth and details.","PeriodicalId":20943,"journal":{"name":"Research & Development in Material Science","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84555938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Droplet-Based Microgels: Attractive Materials for Drug Delivery Systems","authors":"Sammer-Ul Hassan, Xunli Zhang","doi":"10.31031/RDMS.2019.11.000763","DOIUrl":"https://doi.org/10.31031/RDMS.2019.11.000763","url":null,"abstract":"A microgel as defined by IUPAC is “particle of gel of any shape with an equivalent diameter of approximately 0.1 to 100μm”. Baker’s group was one of the first that studied microgels, and “micro” refers to the size and “gel” refers to the structure of the particle [1]. Thus, microgels are cross-linked polymer chains and are similar to macrogels, but they are in the micro-scale. Because of their micro-scale size, microgels have advantages over macrogels, and some of them are mentioned here. i) Microgel suspensions are free-flowing liquids which depend upon volume fraction of swollen particles and cross-linking properties. ii) Microgels respond to changing environment very rapidly, much faster than macrogels, because they have a high surface to volume ratio which transports mass to-and-from the microgels. iii) Exotic microgel morphologies can be used to fine-tune properties. iv) Microgels are considered as colloidal dispersions, and several colloidal science techniques including dynamic light scattering and small range light can provide structural information for microgels. On the other hand, these techniques cannot be used in the case of macrogels. v) Microgels can be assembled into useful larger objects such as 2D assemblies of the air-water and oil-water interfaces [2]. Examples of the 3D structure are colloidal crystals, environmentally sensitive optical properties, and layer-by-layer assemblies. These kinds of assemblies are not feasible when using macrogels.","PeriodicalId":20943,"journal":{"name":"Research & Development in Material Science","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76470077","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Ding, Lili Li, C. Hua, Xinghui Li, Lin Chen, P. Pan, Xianping Wu, Jun Cai, Jinjun Feng
{"title":"A Superior Mechanical Property Nanocrystalline Diamond Film for Extremely Thin Terahertz Traveling Wave Tube Window","authors":"M. Ding, Lili Li, C. Hua, Xinghui Li, Lin Chen, P. Pan, Xianping Wu, Jun Cai, Jinjun Feng","doi":"10.31031/rdms.2019.11.000762","DOIUrl":"https://doi.org/10.31031/rdms.2019.11.000762","url":null,"abstract":"","PeriodicalId":20943,"journal":{"name":"Research & Development in Material Science","volume":"26 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81212691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Plastic Materials for Modifying the Refractive Index of Contact Lens: Overview","authors":"L. M. Shaker, A. Al-Hamdani, A. Al-amiery","doi":"10.31031/rdms.2019.11.000760","DOIUrl":"https://doi.org/10.31031/rdms.2019.11.000760","url":null,"abstract":"","PeriodicalId":20943,"journal":{"name":"Research & Development in Material Science","volume":"233 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77338816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}