Full Scale Measurements and Fatigue Damage Assessment on a Large Container Ship

Norbert Bakkers,Jimmy Tong,Jun-Bum Park 대한조선학회 2011 대한조선학회 학술대회자료집 Vol.2011 No.11

The continuous increase in cargo carrying capability in the container ship sector has led to a rapid growth in container ship sizes. This new generation of large container ships is more sensitive to whipping and springing responses due to the increased flexibility of the hull girder and the prediction of these vibratory responses has become an important element in the design of these ships in term of hull strength and fatigue performance of structural details. This paper describes Lloyd's Register's full scale measurement campaign on board an 8,100 TEU container ship to study the hull girder responses of this ship type in a seaway. The stress measurement indicates that the hull girder vibratory springing and whipping responses are an important factor to be considered in the structural design of the new generation of container ships. The result also highlighted that torsion induced warping stress has a significant contribution to the fatigue damage for the section forward of the engine room. The measurement data has been used for the validation and improvement of Lloyd's Register hull strength and fatigue design procedures.

Andreev reflection versus Coulomb blockade in hybrid semiconductor nanowire devices.

Doh, Yong-Joo,De Franceschi, Silvano,Bakkers, Erik P A M,Kouwenhoven, Leo P American Chemical Society 2008 NANO LETTERS Vol.8 No.12

<P>Semiconductor nanowires provide promising low-dimensional systems for the study of quantum transport phenomena in combination with superconductivity. Here we investigate the competition between the Coulomb blockade effect, Andreev reflection, and quantum interference, in InAs and InP nanowires connected to aluminum-based superconducting electrodes. We compare three limiting cases depending on the tunnel coupling strength and the characteristic Coulomb interaction energy. For weak coupling and large charging energies, negative differential conductance is observed as a direct consequence of the BCS density of states in the leads. For intermediate coupling and charging energy smaller than the superconducting gap, the current-voltage characteristic is dominated by Andreev reflection and Coulomb blockade produces an effect only near zero bias. For almost ideal contact transparencies and negligible charging energies, we observe universal conductance fluctuations whose amplitude is enhanced because of Andreev reflection at the contacts.</P>

Quantum Interference Eects in InAs Semiconductor Nanowires

도용주,Aarnoud L. Roest,Erik P. A. M. Bakkers,Silvano De Franceschi,Leo P. Kouwenhoven 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.54 No.1

We report quantum interference eects in InAs semiconductor nanowires strongly coupled to superconducting electrodes. In the normal state, universal conductance uctuations are investigated as a function of the magnetic eld, the temperature, the bias and the gate voltage. The results are found to be in good agreement with theoretical predictions for weakly disordered one-dimensional conductors. In the superconducting state, the uctuation amplitude is enhanced by a factor up to ~1.6, which is attributed to a doubling of the charge transport via Andreev re ection. At a temperature of 4.2 K, well above the Thouless temperature, conductance uctuations are almost entirely suppressed and the nanowire conductance exhibits anomalous quantization in steps of e^2/h. We report quantum interference eects in InAs semiconductor nanowires strongly coupled to superconducting electrodes. In the normal state, universal conductance uctuations are investigated as a function of the magnetic eld, the temperature, the bias and the gate voltage. The results are found to be in good agreement with theoretical predictions for weakly disordered one-dimensional conductors. In the superconducting state, the uctuation amplitude is enhanced by a factor up to ~1.6, which is attributed to a doubling of the charge transport via Andreev re ection. At a temperature of 4.2 K, well above the Thouless temperature, conductance uctuations are almost entirely suppressed and the nanowire conductance exhibits anomalous quantization in steps of e^2/h.

Superconducting junctions of InAs semiconductor nanowires

도용주,Jorden A. van Dam,Erik P. A. M. Bakkers,Leo P. Kouwenhoven 한국초전도학회 2008 Progress in superconductivity Vol.9 No.2

InAs semiconductor nanowires can provide a promising plat ting quantum circuit, which exploits tunable supercurrent under the operation of gate voltage. We report temperature and magnetic field dependence of the nanowire superconducting junctions, which is in agreement with the proximity-effect theory of superconductor-normal metal-superconductor weak link. Superconducting coherence length of the InAs nanowire is estimated from the fit and magnetic-field dependence of the critical current and the subgap structure of dI/dV is discussed as well.

Superconducting Junctions of InAs Semiconductor Nanowires

Doh, Yong-Joo,Franceschi, Silvano De,van Dam, Jorden A.,Bakkers, Erik P. A. M.,Kouwenhoven, Leo P. The Korean Superconductivity Society 2008 Progress in superconductivity Vol.9 No.2

InAs semiconductor nanowires can provide a promising platform to integrate superconducting quantum circuit, which exploits tunable supercurrent under the operation of gate voltage. We report temperature and magnetic field dependence of the nanowire superconducting junctions, which is in agreement with the proximity-effect theory of superconductor-normal metal-superconductor weak link. Superconducting coherence length of the InAs nanowire is estimated from the fit and magnetic-field dependence of the critical current and the subgap structure of dI/dV is discussed as well.

Induced Systemic Resistance and the Rhizosphere Microbiome

Bakker, Peter A.H.M.,Doornbos, Rogier F.,Zamioudis, Christos,Berendsen, Roeland L.,Pieterse, Corne M.J. The Korean Society of Plant Pathology 2013 Plant Pathology Journal Vol.29 No.2

Microbial communities that are associated with plant roots are highly diverse and harbor tens of thousands of species. This so-called microbiome controls plant health through several mechanisms including the suppression of infectious diseases, which is especially prominent in disease suppressive soils. The mechanisms implicated in disease suppression include competition for nutrients, antibiosis, and induced systemic resistance (ISR). For many biological control agents ISR has been recognized as the mechanism that at least partly explains disease suppression. Implications of ISR on recruitment and functioning of the rhizosphere microbiome are discussed.

STATUS OF FACILITIES AND EXPERIENCE FOR IRRADIATION OF LWR AND V/HTR FUEL IN THE HFR PETTEN

Bakker Klaas,Klaassen Frodo,Schram Ronald,Futterer Michael Korean Nuclear Society 2006 Nuclear Engineering and Technology Vol.38 No.5

The present paper describes the 45 MW High Flux Reactor (HFR) which is located in Petten, The Netherlands. This paper focuses on selected technical aspects of this reactor and on nuclear fuel irradiation experiments. These fuel experiments are mainly experiments on Light Water Reactor (LWR) and Very/High Temperature Reactor (V/HTR) fuels, but also on Fast Reactor (FR) fuels, transmutation fuels and Material Test Reactor (MTR) fuels.

Sacral Insufficiency Fractures : How to Classify?

Bakker, Gesa,Hattingen, Joerg,Stuetzer, Hartmut,Isenberg, Joerg The Korean Neurosurgical Society 2018 Journal of Korean neurosurgical society Vol.61 No.2

Objective : The diagnosis of insufficiency fractures of the sacrum in an elder population increases annually. Fractures show very different morphology. We aimed to classify sacral insufficiency fractures according to the position of cortical break and possible need for intervention. Methods : Between January 1, 2008 and December 31, 2014, all patients with a proven fracture of the sacrum following a low-energy or an even unnoticed trauma were prospectively registered : 117 females and 13 males. All patients had a computer tomography of the pelvic ring, two patients had a magnetic resonance imaging additionally : localization and involvement of the fracture lines into the sacroiliac joint, neural foramina or the spinal canal were identified. Results : Patients were aged between 46 and 98 years (mean, 79.8 years). Seventy-seven patients had an unilateral fracture of the sacral ala, 41 bilateral ala fractures and 12 patients showed a fracture of the sacral corpus : a total of 171 fractures were analyzed. The first group A included fractures of the sacral ala which were assessed to have no or less mechanical importance (n=53) : fractures with no cortical disruption ("bone bruise") (A1; n=2), cortical deformation of the anterior cortical bone (A2; n=4), and fracture of the anterolateral rim of ala (A3; n=47). Complete fractures of the sacral ala (B; n=106) : parallel to the sacroiliac joint (B1; n=63), into the sacroiliac joint (B2; n=19), and involvement of the sacral foramina respectively the spinal canal (B3; n=24). Central fractures involving the sacral corpus (C; n=12) : fracture limited to the corpus or finishing into one ala (C1; n=3), unidirectional including the neural foramina or the spinal canal or both (C2; n=2), and horizontal fractures of the corpus with bilateral sagittal completion (C3; n=8). Sixty-eight fractures proceeded into the sacroiliac joint, 34 fractures showed an injury of foramina or canal. Conclusion : The new classification allowes the differentiation of fractures of less mechanical importance and a risk assessment for possible polymethyl methacrylate leaks during sacroplasty in the direction of the neurological structures. In addition, identification of instable fractures in need for laminectomy and surgical stabilization is possible.

Towards Safety Based Design Procedure for Ships

Bakker, Marijn,Boonstra, Hotze,Engelhard, Wim,Daman, Bart The Society of Naval Architects of Korea 2001 Journal of ship and ocean technology Vol.5 No.3

Present-day rules and regulations for the design and construction of ships are almost without exemption of a prescriptive and deterministic nature. Often it is argued that this situation is far from ideal; it does no right to the advances, which have been made during the past decades in engineering tools in marine technology, both in methodology and in computational power. Within IMO this has been realized for some time and has resulted in proposals to use Formal Safety Assessment(FSA) as a tool to improve and to modernize the rule making process. The present paper makes use of elements of the FSA methodology, but instead of working towards generic regulations or requirements, a Risk Assessment Approach, not unlike a 'safety case'; valid for a certain ship or type of ship is worked out. Delft University of Technology investigated the application of safely assessment procedures in ship design, in co-operation with Anthony Veder Shipowners and safety experts from Safely Service Center BV. The ship considered is a semi-pressurized-fully refrigerated LPG carrier. On the basis of the assumption that a major accident occurs, various accident, scenarios were considered and assessed, which would impair the safety of the carrier. In a so-called Risk Matrix, in which accident frequencies versus the consequence of the scenarios are depicted, the calculated risks all appeared lo be in the ALARP('as low as reasonable practicable') region. A number of design alternatives were compared, both on safety merits and cost-effectiveness. The experience gained with this scenario-based approach will be used to establish a set of general requirements for safety assessment techniques in ship design. In the view that assessment results will be most probably presented in a quasi-quantified manner, the requirements are concerned with uniformity of both the safety assessment. These requirements make it possible that valid comparison between various assessment studies can be made. Safety assessment, founded on these requirements, provides a validated and helpful source of data during the coming years, and provides naval architects and engineers with tools experience and data for safety assessment procedures in ship design. However a lot of effort has to be spent in order to make the methods applicable in day-to-day practice.

Surface Modification of Wool Fabric with POSS® Nanomaterial

Carline Bakker,Arun Ghosh,Surinder Tandon,Steve Ranford 한국섬유공학회 2018 Fibers and polymers Vol.19 No.10

Wool fabrics, without any surface treatment, can undergo undesirable and irreversible structural changes of wool fiber during washing under heat and mechanical agitation, leading to high shrinkage of wool garments. The traditional method based on polyamide resin can prevent felting and/or shrinkage of wool textiles, but adversely affect the surface hydrophobicity. In the present study, a treatment solution was developed based on TriSilanolIsooctyl POSS® and 3- mercaptopropyl trimethoxysilane, which created wool surface with increased hydrophobicity and highly resistant to shrinkage or felting, as measured after 3×5A wash cycles (equivalent to 24 domestic washes). After the treatment, the wool fabric appeared to be superhydrophobic with a water contact angle of above 150 o, compared to the untreated fabric. The treatment has marginal effect on mechanical performance as observed in tensile properties. Scanning electron microscopic images revealed a coating of POSS® on the wool surface. The dyeing of untreated and treated fabrics appeared to be uniform to the naked eye, though spectrophotometric analysis indicated a difference in the extent of dyeing performance. This research showed that POSS®-based treatment is a potentially effective approach for developing shrink-resistant wool textiles with enhanced surface hydrophobicity, in contrast to traditional chlorine/polyamide resin treatment.