Transient thermal response of a highly porous ventilated brake disc

Mew, Timothy D,Kang, Ki-Ju,Kienhö,fer, Frank W,Kim, Tongbeum Professional Engineering Publishing Ltd 2015 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>The transient thermal response of a newly developed ventilated brake disc cored with a porous medium (wire-woven bulk diamond) is compared with those of a solid brake disc and a conventionally ventilated brake disc with pin fins. The best-performing brake disc vis-à-vis the operating temperature is dependent on the duration of braking: for a short braking event, <I>T</I>(solid) < <I>T</I>(pin-finned) < <I>T</I>(porous); however, for extended braking <I>T</I>(porous) < <I>T</I>(pin-finned) < <I>T</I>(solid). These experimental results are explained in terms of the governing thermophysical parameters using a classical first-order unsteady-state differential equation. The initial rate of increase in the brake disc temperature is dominated by the thermal capacity term; hence, for a short braking event, solid discs with a large thermal capacity operate at a low temperature. However, for extended braking, ventilated discs run cooler and reach lower steady-state temperatures than solid rotors do owing to the increased convective surface area and the forced convection in the ventilated channels. With the wire-woven bulk diamond core which allows a slightly lighter disc than the conventional pin-finned disc, a substantially lower steady-state temperature can be achieved, resulting from promoted flow mixing by three-dimensional wire-woven bulk diamond ligaments which enhance convection.</P>

Directed motion of elongated active polymers

Wan, Mew-Bing,Jho, YongSeok The Royal Society of Chemistry 2013 Soft matter Vol.9 No.12

<P>Previous work shows that a net directed motion arises from a system of individual particles undergoing run-and-tumble dynamics in the presence of an array of asymmetric barriers. Here, we show that when the individual particle is replaced by a chain of particles linked to each other by spring forces (polymer), the rectification is enhanced. It is found that the rectification increases when the number of particles in each polymer, as well as its length, increases. In addition, the rectification increases when the size of the opening between neighboring funnel tips, <I>l</I><SUB>o</SUB>, decreases. Interestingly, if the conformal entropic difference exceeds the thermal diffusion, a net directed motion is observed even when the run-and-tumble dynamics approaches Brownian motion. Also, when the inelastic collisions between the particles and the barriers are replaced by elastic collisions, a <I>reversed</I> rectification is observed.</P> <P>Graphic Abstract</P><P>Previous work shows that a net directed motion arises from a system of individual particles undergoing run-and-tumble dynamics in the presence of an array of asymmetric barriers. Here, we show that when the individual particle is replaced by a chain of particles linked to each other by spring forces (polymer) the rectification is enhanced. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c3sm27851d'> </P>

Global Regulatory Trends and its Impact to the Crop Protection Industry

Kersten E. Mewes 한국농약과학회 2007 한국농약과학회 학술발표대회 논문집 Vol.- No.-

Crop Protection (CP) products are already highly regulated in nearly all countries. Scientific progress and an increasing public concern over the adverse effects of Crop Protection products result in even more regulations. These new regulations or new assessment schemes usually originate from either the US, the European Union (EU) or Japan and impact the industry by adding costs and risks to the development of new products. However, there are also positive developments for the industry, in particular the effort in some countries to shorten the review timelines for regulatory submissions. This effort is particularly successful in the US and in some EU member states. On the other hand, the revision of Directive 91/414/EEC, that will probably come into force in 2010, is expected to result in much longer registration time lines in Europe. The R&D costs of a new active ingredient have increased considerably over the last 10 years to more than 200 mio USD. Over the last 15 years an area of particular interest to regulators has been ecotoxicology and the costs to generate the necessary data, in that area, have increased markedly. Data protection and data compensation schemes are well developed in the US. The EU data protection system is under review and a new system will be put in place in approx. 2010 when the new regulation replacing Directive 91/414/EEC comes into force. In 1994 major re-registration programmes were started in the US, EU and Japan, currently resulting in the loss about 50% of the active ingredients in the ED. Secondary regulatory hurdles, e.g. PIC listing, and non-regulatory hurdles, e.g. lists created by the food industry are of increasing concern to the Crop Protection industry.

Effects of magnetic field topology in black hole-neutron star mergers: Long-term simulations

American Physical Society 2017 Physical Review D Vol.95 No.10

<P>We report long-term simulations of black hole-neutron star binary mergers where the neutron star possesses an asymmetric magnetic field dipole. Focusing on the scenario where the neutron star is tidally disrupted by the black hole, we track the evolution of the binary up to approximate to 100 ms after the merger. We uncover more than one episode of thermally driven winds being launched along a funnel wall in all these cases beginning from approximate to 25 ms after the merger. On the other hand, we are unable to conclude presently whether the amount of ejected mass increases with the degree of asymmetry. A large-scale magnetic field configuration in the poloidal direction is formed along the funnel wall accompanied by the generation of a large Poynting flux. The magnetic field in the accretion disk around the black hole remnant is amplified by both magnetic winding and the nonaxisymmetric magnetorotational instability (MRI). The MRI growth is estimated to be in the ideal magnetohydrodynamics (MHD) regime and thus would be free from significant effects induced by potential neutrino radiation. However, the asymmetry in the magnetic field leads to increased turbulence, which causes the vertical magnetic field in the accretion disk to grow largely in a nonlinear manner.</P>

[2nd Prize] David Chipperfield Architects, London

David Chipperfield,Chobham Mews,Agar Grove 현대건축사 2002 월간 CONCEPT Vol.- No.34

Explicit Flavor Symmetry Breaking and Holographic Compact Stars

김영만,신익재,이창환,Mew-Bing Wan 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.4

We study the effects of flavor symmetry breaking on holographic dense matter and compact starsin the D4/D6 model. To this end, two light flavors and one intermediate mass flavor are considered. For two light quarks, we investigate how the strong isospin violation affects the propertiesof holographic dense matter and compact stars. We observe that quark-antiquark condensates areflavor dependent and show interesting behavior near the transition from dense matter with onlyone flavor to matter with two flavors. An intermediate mass quark is introduced to investigate therole of the third flavor. The mass-radius relations of holographic compact stars with three flavorsshow that the mass-radius curve changes drastically at a transition density from which the thirdflavor begins to appear in the matter.

The Influence of Hydrate Formation on Heat Transfer in Gas Pipelines

F. Dorstewitz,D. Mewes 대한기계학회 1993 International Symposium on Transport Phenomena in Vol.2 No.1

The Thermodynamic Coupling of Transport Processes at Liquid / Liquid-Interfaces

Alexander Tokarz,Dieter Mewes 대한기계학회 1998 Heat transter conference Vol.2 No.1

Thermofluidic Characteristics of a Porous Ventilated Brake Disk

Yan, H. B.,Mew, T.,Lee, M.-G.,Kang, K.-J.,Lu, T. J.,Kienhö,fer, F. W.,Kim, T. AMERICAN SOCIETY MECHANICAL ENGINEERS 2015 Journal of Heat Transfer Vol.137 No.2

멸구類(벼멸구 및 흰등멸구)와 水稻病害의 複合發生 被害에 關한 硏究

S.C. LEE,D.M. MATIAS,T.W. MEW,J.S. SORINO,E.A. HEINRICHS 한국응용곤충학회 1985 한국응용곤충학회지 Vol.24 No.2

수도(水稻) 병해충(病害蟲)의 동시발생(同時發生) 피해(被害)에 관한 연구(硏究)를 위한 기초시험(基礎試驗)으로 벼멸구와 흰등멸구의 복합발생(複合發生)에 따른 서식처선호성(棲息處選好性)을 확인(確認)코저 감수성(感受性) 품종(品種)인 IR22와 저항성(抵抗性)인 IR36(분벽최성기(分蘗最盛期)부터 흰등멸구에도 저항성(抵抗性)임)을 공시(供試)하여 조사(調査)한 결과(結果) 벼품종별(品種別), 생육시기별(生育時期別) 및 발생밀도(發生密度)에 따라 다소(多少) 차이(差異)는 있으나 일반적(一般的)으로 흰등멸구는 대부분(大部分) 벼 윗부분(部分)에 서식(棲息)하였고 벼멸구는 아래부분(部分)에 서식(棲息)함을 알 수 있었다. 두 종(種)의 복합발생시(複合發生時)의 서식선호성(棲息選好性)은 상대종(相對種)의 발생(發生)에 영향(影響)을 받지 않았고 각각 일정(一定)한 서식처(棲息處)를 선호(選好)하는 경향(傾向)이었다. 벼멸구의 생태형(生態型) 2에 대(對)하여 반응(反應)이 다른 다섯가지 품종(品種)(IR22 및 TN1: 감수성(感受性), Triveni 및 ASD7: 중정도저항성(中程度抵抗性), IR42: 抵抗性)을 공시(供試)하여 문고병(紋枯病)과 벼멸구의 동시발생(同時發生)에 의한 피해(被害)를 조사(調査)한 결과(結果) 병해충(病害蟲)의 동시발생(同時發生) 피해(被害)는 병원균(病原菌)이 단독발생(單獨發生)했을 때 보다 문고병(紋枯病)의 발병(發病)을 현저(顯著)히 조장(助長)시켰으며 병증(病症)의 발현속도(發現速度)도 빨랐고 균계생장(菌系生長)도 왕성(旺盛)하여 감염기(感染器)(infection structure)의 형성(形成)도 풍부(豊富)하였다. 벼멸구의 생태형(生態型) 2에 대(對)한 품종(品種) 반응(反應)과는 상관없이 벼멸구와 문고병(紋枯病)과의 동시발생(同時發生)은 벼멸구 단독발생(單獨發生)에 비(比)하여 더 심한 고사현상(枯死現象)(hopperburn)을 일으켰다. 즉 문고병(紋枯病) 병원균(病原菌)과 벼멸구의 동시발생(同時發生)은 상승적(相乘的) 피해(被害)가 나타남을 확인(確認)하였다. The locational preference of the brown planthopper (BPH) Nilaparvata lugens () and the whitebacked plant hopper (WBPH) Sogatella furcifera(Horvath) was studied on rice cultivars IR22 and IR36 as an integral part of subsequent research on insect-fungal pathogen relationships. The BPH was observed to stay consistently on the basal portion while the WBPH showed a general preference for the upper portion regardless of varieties, rice growth stages and insect population density levels. The habitat preference of both species (BPH and WBPH) was found not to be affected by the presence of the other species when both species are present on the same host plant Five rice cultivars with different reactions to BPH biotype 2 were used in the study on BPH-Rhizoctonia solani relationship: IR22 and TN1 (susceptible), Triveni and ASD7 (moderately resistant), and IR42 (resistant). Test plants were inoculated with R. solani (Kuhn) days after insect infestation. Sheath blight disease severity/incidence was significantly higher in the treatment where BPH+R. solani were together than in the treatment with only the pathogen. Symptom expression of the disease in the BPH-pathogen combination was faster and mycelial growth was more profuse inducing the formation of more infection structures. Regardless of varietal reaction to BPH biotype 2, the degree of hopperburn was significantly higher in the combination of the two pests as compared with that of BPH alone. There could be a synergistic relationship between the insect pest and the pathogen indicated by a positive interaction between the two species.