IDENTIFICATION CAMPAIGN OF SUPERNOVA REMNANT CANDIDATES IN THE MILKY WAY. I.<i>CHANDRA</i>OBSERVATION OF G308.3-1.4

Hui, C. Y.,Seo, K. A.,Huang, R. H. H.,Trepl, L.,Woo, Y. J.,Lu, T.-N.,Kong, A. K. H.,Walter, F. M. IOP Publishing 2012 The Astrophysical journal Vol.750 No.1

<P>ROSAT all-sky survey data have provided another window in which to search for supernova remnants (SNRs). In re-examining this data archive, a list of unidentified extended X-ray objects have been suggested as promising SNR candidates. However, most of these targets have not yet been fully explored by state-of-the-art X-ray observatories. To select a pilot target for a long-term identification campaign, we observed the brightest candidate, G308.3-1.4, with the Chandra X-ray Observatory. An incomplete shell-like X-ray structure that is well correlated with the radio shell emission at 843 MHz has been revealed. The X-ray spectrum suggests the presence of a shock-heated plasma. All these evidences confirm G308.3-1.4 as an SNR. The brightest X-ray point source detected in this field of view is also the one located closest to the geometrical center of G308.3-1.4, which has a soft spectrum. The intriguing temporal variability and the identification of the optical/infrared counterpart rule out the possibility of an isolated neutron star. On the other hand, the spectral energy distribution from the K-s band to the R band suggests a late-type star. Together with a putative periodicity of similar to 1.4 hr, the interesting excesses in the V and B bands and in H alpha suggest that this source is a promising candidate for a compact binary that survived a supernova explosion.</P>

The competing roles of extensional viscosity and normal stress differences in complex flows of elastic liquids

K. Walters,H.R. Tamaddon-Jahromi,M.F. Webster,M.F. Tomé,S. McKee 한국유변학회 2009 Korea-Australia rheology journal Vol.21 No.4

In various attempts to relate the behaviour of highly-elastic liquids in complex flows to their rheometrical behaviour, obvious candidates for study have been the variation of shear viscosity with shear rate, the two normal stress differences N1 and N2, especially N1, and the extensional viscosity ηE. In this paper, we shall be mainly interested in ‘constant-viscosity’ Boger fluids, and, accordingly, we shall limit attention to N1 and ηE. We shall concentrate on two important flows - axisymmetric contraction flow and “splashing” (particularly that which arises when a liquid drop falls onto the free surface of the same liquid). Modern numerical techniques are employed to provide the theoretical predictions. It is shown that the two obvious manifestations of viscoelastic rheometrical behaviour can sometimes be opposing influences in determining flow characteristics. Specifically, in an axisymmetric contraction flow, high ηE can retard the flow, whereas high N1 can have the opposite effect. In the splashing experiment, high ηE can certainly reduce the height of the so-called Worthington jet, thus confirming some early suggestions, but, again, other rheometrical influences can also have a role to play and the overall picture may not be as clear as it was once envisaged.

Structural response of composite concrete filled plastic tubes in compression

Walter O. Oyawa,Naftary K. Gathimba,Geoffrey N. Mang’uriu 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.3

Kenya has recently experienced worrying collapse of buildings during construction largely attributable to the poor quality of in-situ concrete and poor workmanship. The situation in the country is further compounded by rapid deterioration of infrastructure, hence necessitating the development of alternative structural systems such as concrete filled unplasticized poly vinyl chloride (UPVC) tubes as columns. The work herein adds on to the very limited and scanty work on use of UPVC tubes in construction. This study presents the findings of experimental and analytical work which investigated the structural response of composite concrete filled UPVC tubes under compressive load regime. UPVC pipes are cheaper than steel tubes and can be used as formwork during construction and thereafter as an integral part of column. Key variables in this study included the strength of infill concrete, the length to diameter ratio (L/D) of the plastic tube, as well as the diameter to thickness ratio (D/2t) of the plastic tube. Plastic tubes having varying diameters and heights were used to confine concrete of different strengths. Results obtained in the study clearly demonstrate the effectiveness of UPVC tubes as a confining medium for infill concrete, attributable to enhanced composite interaction between the UPVC tube and infill concrete medium. It was determined that compressive strength of the composite column specimens increased with increased concrete strength while the same decreased with increased column height, albeit by a small margin since all the columns considered were short columns. Most importantly, the experimental confined concrete strength increased significantly when compared to unconfined concrete strength; the strength increased between 1.18 to 3.65 times the unconfined strength. It was noted that lower strength infill concrete had the highest confined strength possibly due to enhanced composite interaction with the confining UPVC tube. The study further proposes an analytical model for the determination of confined strength of concrete.

Yi Sang's Perpetual Audacity

Walter K.Lew Poet, Literary Critic The Korea Foundation 2000 Koreana (English) Vol.14 No.4

The competing roles of extensional viscosity and normal stress differences in complex flows of elastic liquids

Walters, K.,Tamaddon-Jahromi, H.R.,Webster, M.F.,Tome, M.F.,McKee, S. The Korean Society of Rheology 2009 Korea-Australia rheology journal Vol.21 No.4

In various attempts to relate the behaviour of highly-elastic liquids in complex flows to their rheometrical behaviour, obvious candidates for study have been the variation of shear viscosity with shear rate, the two normal stress differences $N_1$ and $N_2$, especially $N_1$, and the extensional viscosity $\eta_E$. In this paper, we shall be mainly interested in 'constant-viscosity' Boger fluids, and, accordingly, we shall limit attention to $N_1$ and $\eta_E$. We shall concentrate on two important flows - axisymmetric contraction flow and "splashing" (particularly that which arises when a liquid drop falls onto the tree surface of the same liquid). Modern numerical techniques are employed to provide the theoretical predictions. It is shown that the two obvious manifestations of viscoelastic rheometrical behaviour can sometimes be opposing influences in determining flow characteristics. Specifically, in an axisymmetric contraction flow, high $\eta_E$ can retard the flow, whereas high $N_1$ can have the opposite effect. In the splashing experiment, high $\eta_E$ can certainly reduce the height of the so-called Worthington jet, thus confirming some early suggestions, but, again, other rheometrical influences can also have a role to play and the overall picture may not be as clear as it was once envisaged.

YI SANG

Walter K. Lew 이상문학회 2003 이상리뷰 Vol.- No.2

JEAN COCTEAU IN THE LOOKING GLASS : A HomotextualReadingofYiSang s MirrorPoems

Walter K. Lew 이상문학회 2001 이상리뷰 Vol.- No.1

Lessons from history

Walters, K. The Korean Society of Rheology 1999 Korea-Australia rheology journal Vol.11 No.4

The main events in the historical development of Rheology are traced and particular attention is paid to the leading players, the controversies, the priority disputes and the nomenclature disagreements. Some of the lessons to be learned from the past are then highlighted and a positive assessment is given of the prospects for rheological research in the next millennium

A General approach to the wrinkling instability of sandwich plates

Vonach, Walter K.,Rammerstorfer, Franz G. Techno-Press 2001 Structural Engineering and Mechanics, An Int'l Jou Vol.12 No.4

Sandwich plates are widely used in lightweight design due to their high strength and stiffness to weight ratio. Due to the heterogeneous structure of sandwich plates, they can exhibit local instabilities (wrinkling), which lead to a sudden loss of stiffness in the structure. This paper presents an analytical solution to the wrinkling problem of sandwich plates. The solution is based on the Rayleigh-Ritz method, by assuming an appropriate deformation field. In contrast to the other approaches up to now, this model takes arbitrary and different orthotropic face layers, finite core thickness and orthotropic core material into account. This approach is the first to cover the wrinkling of unsymmetric sandwiches and sandwiches composed of orthotropic FRP face layers, which are most common in advanced lightweight design. Despite the generality of the solution, the computational effort is kept within bounds. The results have been verified using other analytical solutions and unit cell 3D FE calculations.

Price Forecasting on a Large Scale Data Set using Time Series and Neural Network Models

Preetha K G,K R Remesh Babu,Sangeetha U,Rinta Susan Thomas,Saigopika,Shalon Walter,Swapna Thomas 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.12

Environment, price, regulation, and other factors influence the price of agricultural products, which is a social signal of product supply and demand. The price of many agricultural products fluctuates greatly due to the asymmetry between production and marketing details. Horticultural goods are particularly price sensitive because they cannot be stored for long periods of time. It is very important and helpful to forecast the price of horticultural products which is crucial in designing a cropping plan. The proposed method guides the farmers in agricultural product production and harvesting plans. Farmers can benefit from long-term forecasting since it helps them plan their planting and harvesting schedules. Customers can also profit from daily average price estimates for the short term. This paper study the time series models such as ARIMA, SARIMA, and neural network models such as BPN, LSTM and are used for wheat cost prediction in India. A large scale available data set is collected and tested. The results shows that since ARIMA and SARIMA models are well suited for small-scale, continuous, and periodic data, the BPN and LSTM provide more accurate and faster results for predicting well weekly and monthly trends of price fluctuation.