Malaysia’s Maritime Security Challenges and the Development of the Royal Malaysian Navy: Old Problems and New Threats

( Lukasz Stach ) 한국국방연구원 2018 The Korean Journal of Defense Analysis Vol.30 No.3

The situation in Southeast Asia brings attention not only to the regional countries, but also to the great powers. The growing People’s Republic of China’s economy and military especially causes concern regarding the stability of the whole Southeast Asia region. Smaller Southeast Asian countries may be overwhelmed by China. Amongst these countries is Malaysia, which tries to secure its national interest in the region, especially in the South China Sea. Malaysia faces some maritime security threats caused by its stakes in the Spratly Islands dispute. The article attempts to elucidate the contemporary condition of the Royal Malaysian Navy (RMN), especially in the field of warships. Moreover, the study tries to answer the question of why the RMN is an important branch of the Malaysian Armed Forces and plays a vital role in securing Malaysian safety. The article is divided into two parts. The first describes the problems which Malaysia faces in the field of maritime security. The second elaborates the assets of the RMN, mostly in major combatant ships. This paper concludes with a summary of the RMN’s major vessels that have been and will be developed from 1990 to 2025.

Multifractal Characterization of Water Soluble Copper Phthalocyanine Based Films Surfaces

Ştefan Ţălu,Sebastian Stach,Aman Mahajan,Dinesh Pathak,Tomas Wagner,Anshul Kumar,R. K. Bedi,Mihai Ţălu 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.4

This paper presents a multifractal approach to characterize the structural complexity of 3D surface roughness of CuTsPc films on the glass and quartz substrate, obtained with atomic force microscopy (AFM) analysis. CuTsPc films prepared by drop cast method were investigated. CuTsPc films surface roughness was studied by AFM in tapping-mode™, in an aqueous environment, on square areas of 100 μm2 and 2500 μm2. A detailed methodology for CuTsPc films surface multifractal characterization, which may be applied for AFM data, was also presented. Analysis of surface roughness revealed that CuTsPc films have a multifractal geometry at various magnifications. The generalized dimension Dq and the singularity spectrum f(α) provided quantitative values that characterize the local scale properties of CuTsPc films surface morphology at nanometer scale. Multifractal analysis provides different yet complementary information to that offered by traditional surface statistical parameters.

Anesthesia for the patient with a recently diagnosed concussion: think about the brain!

Mohammed R. Rasouli,Michelle Kavin,Stephen Stache,Michael E. Mahla,Eric S. Schwenk 대한마취통증의학회 2020 Korean Journal of Anesthesiology Vol.73 No.1

Some patients require emergent, urgent, or elective surgery in the time period immediately following diagnosis of concussion. However, changes in brain homeostatic mechanisms following a concussion and concern for secondary brain injury can complicate the decision as to whether or not a surgery should proceed or be postponed. Given the paucity of available evidence, further evaluation of the use of anesthesia in a patient with concussion is warranted. This article summarizes what is currently known about the relevant pathophysiology of concussion, intraoperative anesthesia considerations, and effects of anesthesia on concussion outcomes in an attempt to help providers understand the risks that may accompany surgery and anesthesia in this patient population. While most contraindications to the use of anesthesia in concussed patients are relative, there are nonetheless pathophysiologic changes associated with a concussion that can increase risk of its use. Understanding these changes and anesthetic implications can help providers optimize outcomes in this patient population.

Pile in the Unsaturated Cracked Substrate with Reliability Assessment based on Neural Networks

Janusz Vitalis Kozubal,Wojciech Puła,Mateusz Stach 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.9

In this study, we present reliability assessments for a monopile socketed into a vertical fissured unsaturated substrate correlated with the degree of saturation. The pile was loaded by concentrated lateral force in a three-dimensional space. Procedures were prepared in the numerical analysis software FLAC 3D, fast lagrangian analysis of continua. FISH, a scripting language embedded within FLAC, was used to control the depth of cracks in unsaturated soil and manage a significant number of the calculations. The presented approach expands knowledge about piles loaded laterally and also the considerable influence of environmental changes. In the reliability part of the study, the excessive horizontal displacement of the pile head was examined as an implicit function. The analytical model of vertical water flux in the partially saturated soil was applied in connection with the iterative solution of the cracked depth of the substrate. The suction profile was estimated for a layer above the groundwater level. An important aspect of this paper is that the reliability analyses were prepared for this task in complex environmental conditions and with a horizontal load. All limit state functions were approximated following the response surface methodology, which was defined by neural networks based on modified perceptrons and was compared with well-known polynomials functions.

Au Transport in Catalyst Coarsening and Si Nanowire Formation

Kim, B. J.,Tersoff, J.,Kodambaka, S.,Jang, Ja-Soon,Stach, E. A.,Ross, F. M. American Chemical Society 2014 NANO LETTERS Vol.14 No.8

<P>The motion of Au between AuSi liquid eutectic droplets, both before and during vapor–liquid–solid growth, is important in controlling tapering and diameter uniformity in Si nanowires. We measure the kinetics of coarsening of AuSi droplets on Si(001) and Si(111), quantifying the size evolution of droplets during annealing in ultrahigh vacuum using in situ transmission electron microscopy. For individual droplets, we show that coarsening kinetics are modified when disilane or oxygen is added: coarsening rates increase in the presence of disilane but decrease in oxygen. Matching droplet size measurements on Si(001) with coarsening models confirms that Au transport is driven by capillary forces and that the kinetic coefficients depend on the gas environment present. We suggest that the gas effects are qualitatively similar whether transport is attachment limited or diffusion limited. These results provide insight into manipulating nanowire morphologies for advanced device fabrication.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2014/nalefd.2014.14.issue-8/nl501582q/production/images/medium/nl-2014-01582q_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl501582q'>ACS Electronic Supporting Info</A></P>

Growth Pathways in Ultralow Temperature Ge Nucleation from Au

Kim, B. J.,Wen, C.-Y.,Tersoff, J.,Reuter, M. C.,Stach, E. A.,Ross, F. M. American Chemical Society 2012 NANO LETTERS Vol.12 No.11

<P>Device integration on flexible or low-cost substrates has driven interest in the low-temperature growth of semiconductor nanostructures. Using in situ electron microscopy, we examine the Au-catalyzed growth of crystalline Ge at temperatures as low as 150 °C. For this materials system, the model for low temperature growth of nanowires, we find three distinct reaction pathways. The lowest temperature reactions are distinguished by the absence of any purely liquid state. From measurements of reaction rates and parameters such as supersaturation, we explain the sequence of pathways as arising from a kinetic competition between the imposed time scale for Ge addition and the inherent time scale for Ge nucleation. This enables an understanding of the conditions under which catalytic Ge growth can occur at very low temperatures, with implications for nanostructure formation on temperature-sensitive substrates.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2012/nalefd.2012.12.issue-11/nl303225a/production/images/medium/nl-2012-03225a_0006.gif'></P>

Syntheses of Boron Nitride Nanotubes from Borazine and Decaborane Molecular Precursors by Catalytic Chemical Vapor Deposition with a Floating Nickel Catalyst

Chatterjee, Shahana,Kim, Myung Jong,Zakharov, Dmitri N.,Kim, Seung Min,Stach, Eric A.,Maruyama, Benji,Sneddon, Larry G. American Chemical Society 2012 Chemistry of materials Vol.24 No.15

<P>Multi- and double-walled boron nitride nanotubes (BNNTs) have been synthesized with the aid of a floating nickel catalyst via the catalytic chemical vapor deposition (CCVD) of either the amine-borane borazine (B<SUB>3</SUB>N<SUB>3</SUB>H<SUB>6</SUB>) or the polyhedral-borane decaborane (B<SUB>10</SUB>H<SUB>14</SUB>) molecular precursors in ammonia atmospheres. Both sets of BNNTs were crystalline with highly ordered structures. The BNNTs grown at 1200 °C from borazine were mainly double-walled, with lengths up to 0.2 μm and ∼2 nm diameters. The BNNTs grown at 1200–1300 °C from decaborane were double- and multiwalled, with the double-walled nanotubes having ∼2 nm inner diameters and the multiwalled nanotubes (∼10 walls) having ∼4–5 nm inner diameters and ∼12–14 nm outer diameters. BNNTs grown from decaborane at 1300 °C were longer, averaging ∼0.6 μm, whereas those grown at 1200 °C had average lengths of ∼0.2 μm. The BNNTs were characterized using scanning and transmission electron microscopies (SEM and TEM), and electron energy loss spectroscopy (EELS). The floating catalyst method provides a catalytic and potentially scalable route to BNNTs with low defect density from safe and commercially available precursor compounds.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2012/cmatex.2012.24.issue-15/cm3006088/production/images/medium/cm-2012-006088_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm3006088'>ACS Electronic Supporting Info</A></P>

Real time observation of ZnO nanostructure formation via the solid-vapor and solid-solid-vapor mechanisms.

Kim, B J,Kim, M W,Jang, J S,Stach, E A RSC Pub 2014 Nanoscale Vol.6 No.12

<P>We report in situ transmission electron microscopy studies of the formation of ZnO nanostructures--nanoscale depressions, nanoholes, nanoribbons, and nanosheets--and the phase stability and kinetics of Au catalysts on ZnO. During annealing, the ZnO layer produces hexagonally shaped, vertical nanoscale depressions, which increase in size along the ? 0001 ? growth direction through preferential dissociation from the {101[combining macron]0} facet and which subsequently form hexagonal islands at their six-fold junctions. Real time observations of the annealing of Au deposited on ZnO show that the catalysts remain solid up to 900 C, an observation that has implications regarding ZnO nanowire growth via the vapor-solid-solid mechanism (VSS). The Au also creates hexagonal nanoscale holes only at the location of solid Au catalysts, via the solid-solid-vapor (SSV) mechanism. Importantly, coarsening of the Au particles is negligible due to limited Au diffusion on the side facets of the nanoscale depressions, suggesting an approach to the growth of uniform hybrid nanowires with control over both diameter and location. Furthermore, we directly monitor the evolution of the transformation of a nanoribbon into a nanosheet with {101[combining macron]0} facets. This process takes place through a periodic, kinetic roughening transition of the surface, which is controlled by the kinetic competition between surface growth and the transfer of evaporated gases. In total, these observations give new insights into multiple growth processes occurring in this important materials system.</P>

Correlating Structural Changes and Gas Evolution during the Thermal Decomposition of Charged Li_<i>x</i>Ni_0.8Co_0.15Al_0.05O₂ Cathode Materials

Bak, Seong-Min,Nam, Kyung-Wan,Chang, Wonyoung,Yu, Xiqian,Hu, Enyuan,Hwang, Sooyeon,Stach, Eric A.,Kim, Kwang-Bum,Chung, Kyung Yoon,Yang, Xiao-Qing American Chemical Society 2013 Chemistry of materials Vol.25 No.3

<P>In this work, we present results from the application of a new in situ technique that combines time-resolved synchrotron X-ray diffraction and mass spectroscopy. We exploit this approach to provide direct correlation between structural changes and the evolution of gas that occurs during the thermal decomposition of (over)charged cathode materials used in lithium-ion batteries. Results from charged Li<SUB><I>x</I></SUB>Ni<SUB>0.8</SUB>Co<SUB>0.15</SUB>Al<SUB>0.05</SUB>O<SUB>2</SUB> cathode materials indicate that the evolution of both O<SUB>2</SUB> and CO<SUB>2</SUB> gases are strongly related to phase transitions that occur during thermal decomposition, specifically from the layered structure (space group <I>R</I>3̅<I>m</I>) to the disordered spinel structure (<I>Fd</I>3̅<I>m</I>), and finally to the rock-salt structure (<I>Fm</I>3̅<I>m</I>). The state of charge also significantly affects both the structural changes and the evolution of oxygen as the temperature increases: the more extensive the charge, the lower the temperature of the phase transitions and the larger the oxygen release. Ex situ X-ray absorption spectroscopy (XAS) and in situ transmission electron microscopy (TEM) are also utilized to investigate the local structural and valence state changes in Ni and Co ions, and to characterize microscopic morphology changes. The combination of these advanced tools provides a unique approach to study fundamental aspects of the dynamic physical and chemical changes that occur during thermal decomposition of charged cathode materials in a systematic way.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2013/cmatex.2013.25.issue-3/cm303096e/production/images/medium/cm-2012-03096e_0014.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm303096e'>ACS Electronic Supporting Info</A></P>

Investigating Local Degradation and Thermal Stability of Charged Nickel-Based Cathode Materials through Real-Time Electron Microscopy

Hwang, Sooyeon,Kim, Seung Min,Bak, Seong-Min,Cho, Byung-Won,Chung, Kyung Yoon,Lee, Jeong Yong,Chang, Wonyoung,Stach, Eric A. American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.17

<P>In this work, we take advantage of in situ transmission electron microscopy (TEM) to investigate thermally induced decomposition of the surface of Li<SUB><I>x</I></SUB>Ni<SUB>0.8</SUB>Co<SUB>0.15</SUB>Al<SUB>0.05</SUB>O<SUB>2</SUB> (NCA) cathode materials that have been subjected to different states of charge (SOC). While uncharged NCA is stable up to 400 °C, significant changes occur in charged NCA with increasing temperature. These include the development of surface porosity and changes in the oxygen K-edge electron energy loss spectra, with pre-edge peaks shifting to higher energy losses. These changes are closely related to O<SUB>2</SUB> gas released from the structure, as well as to phase changes of NCA from the layered structure to the disordered spinel structure, and finally to the rock-salt structure. Although the temperatures where these changes initiate depend strongly on the state of charge, there also exist significant variations among particles with the same state of charge. Notably, when NCA is charged to <I>x</I> = 0.33 (the charge state that is the practical upper limit voltage in most applications), the surfaces of some particles undergo morphological and oxygen K-edge changes even at temperatures below 100 °C, a temperature that electronic devices containing lithium ion batteries (LIB) can possibly see during normal operation. Those particles that experience these changes are likely to be extremely unstable and may trigger thermal runaway at much lower temperatures than would be usually expected. These results demonstrate that in situ heating experiments are a unique tool not only to study the general thermal behavior of cathode materials but also to explore particle-to-particle variations, which are sometimes of critical importance in understanding the performance of the overall system.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-17/am503278f/production/images/medium/am-2014-03278f_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am503278f'>ACS Electronic Supporting Info</A></P>