scholarly journals Ultrastiff graphene

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Vesa-Matti Hiltunen ◽  
Pekka Koskinen ◽  
Kamila K. Mentel ◽  
Jyrki Manninen ◽  
Pasi Myllyperkiö ◽  
...  
Keyword(s):  
Bending Stiffness ◽  
Point Of View ◽  
Pristine Graphene ◽  
Thin Membrane ◽  
3D Scaffolds ◽  
Suspended Graphene ◽  
Application Point ◽  
Out Of Plane ◽  
New Applications ◽  
Graphene Membranes

AbstractGraphene has exceptionally high in-plane strength, which makes it ideal for various nanomechanical applications. At the same time, its exceptionally low out-of-plane stiffness makes it also flimsy and hard to handle, rendering out-of-plane structures unstable and difficult to fabricate. Therefore, from an application point of view, a method to stiffen graphene would be highly beneficial. Here we demonstrate that graphene can be significantly stiffened by using a laser writing technique called optical forging. We fabricate suspended graphene membranes and use optical forging to create stable corrugations. Nanoindentation experiments show that the corrugations increase graphene bending stiffness up to 0.8 MeV, five orders of magnitude larger than pristine graphene and corresponding to some 35 layers of bulk graphite. Simulations demonstrate that, in addition to stiffening by micron-scale corrugations, optical forging stiffens graphene also at the nanoscale. This magnitude of stiffening of an atomically thin membrane will open avenues for a plethora of new applications, such as GHz resonators and 3D scaffolds.

scholarly journals Peran Aplikasi “Visiting Jogja” dalam Mengembalikan Kepercayaan Wisatawan untuk Berwisata ke Yogyakarta

2021 ◽  
Vol 5 (2) ◽  
pp. 128
Author(s):  
Fitria Jalaluddin ◽  
Alfelia Nugky Permatasari
Keyword(s):  
Point Of View ◽  
The Public ◽  
Advantages And Disadvantages ◽  
Daily Mobility ◽  
Tourism Sector ◽  
Major Loss ◽  
Tourism Destinations ◽  
Tourism Attractions ◽  
New Applications ◽  
Special Region

Covid-19 made several countries adopt lock-down policies as an effort to break the chain of spreading the virus. However, this policy greatly affects sectors related to the daily mobility of people, especially the tourism sector which has been most significantly affected by Covid-19. One of the provinces in Indonesia that has experienced a major loss in the tourism sector due to Covid-19 is the Yogyakarta Special Region (DIY). Therefore, the DIY government gradually continues to encourage the tourism sector to resume operations, one of which is by releasing new applications for tourists, namely "Jogja Pass" and "Visiting Jogja" to monitor visitors to tourism destinations in DIY. In this study the author will focus on studying the application "Visiting Jogja". The purpose of this research is to examine the advantages and disadvantages of the "Visiting Jogja" application from the user's point of view, and to find out whether the "Visiting Jogja" application can help restore the confidence of tourists to travel to Yogyakarta. This study uses qualitative research methods, with data collection techniques through direct interviews with 10 respondents as a sample who is determined randomly. The results show that the application "Visiting Jogja" can provide assurance for tourists, which helps generate confidence in users to visit more tourism attractions in Yogyakarta. However, the government's efforts in socializing and promoting the “Visiting Jogja” application to the public are still lacking.

scholarly journals Internal donors on supported Ziegler Natta catalysts for isotactic polypropylene: a brief tutorial review

2021 ◽  
Vol 28 (10) ◽  
Author(s):  
Bharat R. Paghadar ◽  
J. B. Sainani ◽  
Samith K. M. ◽  
Poornima Bhagavath
Keyword(s):  
Polymeric Materials ◽  
Detailed Comparison ◽  
Short Review ◽  
Point Of View ◽  
Polymer Science ◽  
Cross Combination ◽  
Polymer Properties ◽  
Technical Advances ◽  
Catalyst Systems ◽  
New Applications

AbstractThe scientific and technical advances in the field of polymer science has been abundant in recent years. Amongst the various polymeric materials available in market, synthesis of polyolefins has been in the forefront since decades. A major challenge in this domain remains in attaining stereoregular polyolefins especially polypropylene (PP) and significant efforts were carried out by synthesizing various internal donors (ID) aiding the catalysts involved in producing them. This short review gives an overview of i) various generations of Ziegler–Natta (ZN) catalyst systems ii) general classes of ID that has been demonstrated by the researchers over the past decades iii) their influence on PP isotacticity and polymer properties. The coordination modes of different donor classes on supported ZN system and comparative study especially between phthalate and diether ID classes were also addressed here. This review also presents the studies carried out on phthalate catalyst structure analysis, detailed comparison study on phthalate and diether IDs in terms of PP isotacticity, regioselectivity, hydrogen response, and also their cross combination study and competitive behavior. Further a brief description on other structurally varied IDs like malonates, maleates, silyl diol esters, bifunctional donors, multi ether donors demonstrated for isotactic PP were also presented. Studies conducted on compatibility of incorporation of two different classes of IDs on a single supported ZN system for the fundamental understanding of the catalyst behavior; and also on how mixed donor approach enables in tuning the catalyst for polymer properties were also presented. This review also provides an opportunity to the young minds and the basic researchers from academic point of view by and large to create new polymeric materials with useful properties or modify the existing materials for new applications by incorporating new IDs for further improvisation of the stereo regularity in obtaining the polymers. Graphic Abstract

Vibrations of an Intermediately Supported U-Bend Tube

1975 ◽  
Vol 97 (1) ◽  
pp. 23-32 ◽  
Author(s):  
L. S. S. Lee
Keyword(s):  
Natural Frequency ◽  
Natural Frequencies ◽  
Experimental Tests ◽  
Bending Stiffness ◽  
Stiffness Ratio ◽  
Plane Vibration ◽  
Straight Beam ◽  
Out Of Plane ◽  
Straight Segments ◽  
Good Agreement

Vibrations of an intermediately supported U-bend tube fall into two independent classes as an incomplete ring of single span does, namely, the in-plane vibration and the coupled twist-bending out-of-plane vibration. Natural frequencies may be expressed in terms of a coefficient p which depends on the stiffness ratio k, the ratio of lengths of spans, and the supporting conditions. The effect of the torsional flexibility of a curved bar acts to release the bending stiffness of a straight beam and hence decrease the natural frequency. Some conclusions for an incomplete ring of single span may not be equally well applicable to the U-tube case due to the effects of intermediate supports and the presence of the supporting straight segments. Results of the analytical predictions and the experimental tests of an intermediately supported U-tube are in good agreement.

Analysis of Omega-Gate Nanowire SOI MOSFET Under Analog Point of View

2020 ◽  
Vol 15 (1) ◽  
pp. 1-6
Author(s):  
Welder Fernandes Perina ◽  
João Antonio Martino ◽  
Paula Ghedini Der Agopian
Keyword(s):  
Point Of View ◽  
Short Channel Effects ◽  
Theoretical Limit ◽  
Short Channel ◽  
Worst Case ◽  
Channel Effects ◽  
Electrostatic Coupling ◽  
Channel Lengths ◽  
P Type ◽  
New Applications

This paper presents an evaluation of omega-gate nanowire n- and p-type SOI MOSFETs performance focusing on the main analog figures of merit. The different channel widths (WNW) and channel lengths (L) were also evaluated. These devices presented values of subthreshold slope near the theoretical limit at room temperature (60 mV/dec) and in the worst case a DIBL value smaller than 70 mV/V showing its immunity to short channel effects (SCEs) in the range studied. The narrowest device showed great electrostatic coupling, improving transconductance (gm), presenting an unit gain frequency over 200 GHz and intrinsic voltage gain over 80 dB. These values suggests that this device is capable of achieving good performance on new applications such as 5G communications and Internet-of-Things (IoT).

Rough Sets and Approximate Reasoning

2014 ◽  
pp. 180-228 ◽  
Author(s):  
B. K. Tripathy
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Sets ◽  
Rough Sets ◽  
Intuitionistic Fuzzy Sets ◽  
Point Of View ◽  
Approximate Reasoning ◽  
Human Reasoning ◽  
Intuitionistic Fuzzy ◽  
Application Point ◽  
Future Work

Several models have been introduced to capture impreciseness in data. Fuzzy sets introduced by Zadeh and Rough sets introduced by Pawlak are two of the most popular such models. In addition, the notion of intuitionistic fuzzy sets introduced by Atanassov and the hybrid models obtained thereof have been very fruitful from the application point of view. The introduction of fuzzy logic and the approximate reasoning obtained through it are more realistic as they are closer to human reasoning. Equality of sets in crisp mathematics is too restricted from the application point of view. Therefore, extending these concepts, three types of approximate equalities were introduced by Novotny and Pawlak using rough sets. These notions were found to be restrictive in the sense that they again boil down to equality of sets and also the lower approximate equality is artificial. Keeping these points in view, three other types of approximate equalities were introduced by Tripathy in several papers. These approximate equalities were further generalised to cover the approximate equalities of fuzzy sets and intuitionistic fuzzy sets by him. In addition, considering the generalisations of basic rough sets like the covering-based rough sets and multigranular rough sets, the study has been carried out further. In this chapter, the authors provide a comprehensive study of all these forms of approximate equalities and illustrate their applicability through several examples. In addition, they provide some problems for future work.

scholarly journals Implicit max-stable extremal integrals

Extremes ◽  
2020 ◽  
Author(s):  
D. Kremer
Keyword(s):  
Loss Function ◽  
Open Problem ◽  
Stochastic Integral ◽  
Extreme Values ◽  
Stable Distributions ◽  
Extreme Value ◽  
Point Of View ◽  
Extreme Value Distributions ◽  
Application Point ◽  
Deterministic Function

Abstract Recently, the notion of implicit extreme value distributions has been established, which is based on a given loss function f ≥ 0. From an application point of view, one is rather interested in extreme loss events that occur relative to f than in the corresponding extreme values itself. In this context, so-called f -implicit α-Fréchet max-stable distributions arise and have been used to construct independently scattered sup-measures that possess such margins. In this paper we solve an open problem in Goldbach (2016) by developing a stochastic integral of a deterministic function g ≥ 0 with respect to implicit max-stable sup-measures. The resulting theory covers the construction of max-stable extremal integrals (see Stoev and Taqqu Extremes 8, 237–266 (2005)) and, at the same time, reveals striking parallels.

A Prenecking Strategy Makes Stretched Membranes With Clamped Ends Wrinkle-Free

2017 ◽  
Vol 84 (6) ◽  
Author(s):  
Ming Li ◽  
Yangjun Luo ◽  
HuaPing Wu ◽  
Kai Zhu ◽  
Yanzhuang Niu ◽  
...  
Keyword(s):  
Topology Optimization ◽  
Design Optimization ◽  
Computer Aided Design ◽  
Discrete Topology ◽  
Shape Accuracy ◽  
Computer Aided ◽  
Out Of Plane ◽  
Promising Solution ◽  
Aided Design ◽  
Graphene Membranes

For both polyimide membranes in aerospace and graphene membranes in nanoelectronics with surface accuracy requirements, wrinkles due to the extreme out-of-plane flexibility yield inverse influences on the properties and applications of membranes. In this study, on the basis of discrete topology optimization, we propose a prenecking strategy by adopting elliptical free edges to suppress the stretch-induced wrinkling. This prenecking strategy with the computer-aided-design (CAD)-ready format is versatile to eliminate wrinkles in stretched membranes with clamped ends and achieve wrinkle-free performances. The wrinkle-free capability of the prenecking strategy, capable of satisfying the shape accuracy requirements, indicates that by suffering insignificant area loss, concerning of wrinkling problems in membranes is no further required. As compared with the existing researches focusing on studying wrinkling behaviors, the prenecking strategy offers a promising solution to the stretch-induced wrinkling problem by eliminating wrinkles through design optimization.

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