Lactobacillus casei 34143のニトロソグアニジン処理変異株による大豆乳での乳酸およびジアセチル生成

Production of acid and diacetyl by nitrosoguanidine mutants of Lactobacillus casei 34143 was evaluated in soymilk. Optimum temperature for growthof the five cultures varied between 34.5 and 35.9℃. However, the temperature required for maximum production of diacetyl in soymilk in the parent culture was 32.7℃ and mutants such as N-14, N-15 and N-25 required a temperature of 29.6℃, while another mutant, L-7 required 26.4℃ for production of diacetyl. Parent and mutant cultures were deficient in citrate permease and citritase synthetic mechanisms, although lactose-utilising mutants (N-25 and S-3-1) possessed both β-galactosidase and phospho-β-galactosidase.大豆乳の発酵に有効な乳酸菌株を検索する目的で、ラクトース非発酵性Lactobacillus casei 34143のニトロソグアニジン(NTG)処理変異株について、液体培地での生育性ならびに大豆乳培地での乳酸とジアセチル生成能を温度勾配培養法によって検討した。また、NTG処理変異株におけるクエン酸およびラクトースの取り込みと分解に関与する酵素の活性についても調べた。その結果、親株ならびに変異株の液体培地での生育至適温度はほぼ同じ値を示し、いずれも34.5℃から35.9℃の範囲であった。しかしながら、大豆乳培地での乳酸とジアセチル生生成能には違いを示す菌株があった。とくにジアセル生成の至適温度は親株が32.7℃であるのに対して、変異株(N-14株,N-15株およびN-25株)では29.6℃であり、そして変異株のL-7株では26.4℃であった。一方、供試した親株と変異株のはすべてクエン酸透過酵素ならびにクエン酸分解酵素活性を示さなかったが、ラクトース代謝能を獲得した変異株(N-25株とS-3-1株)はβ-ガラクトシダーゼとフォスフォ-β-ガラクトシダーゼの活性を示した

Optimal control of piezoelectric anisotropic plates

This paper is concerned with the application of optimal control techniques to a static piezoelectric anisotropic thin plate model. To take physical limitations into account, the space of electric potential fields is restricted, i.e., control constraints are imposed. After deriving the first-order necessary conditions for the problem, a primal-dual active set strategy for its solution is presented. In a numerical study we consider a plate composed of two layers of different piezoelectric materials. We investigate the abilities of our approach and the influence of certain parameters

Wave attenuation in mangrove forests; field data obtained in Trang, Thailand

Mangroves thrive in sheltered intertidal areas in the tropics and sub-tropics. Due to this position at the interface between land and sea, mangroves play an important role in the attenuation of waves. Dissipation of wave energy in mangrove forests is an interesting feature from the viewpoint of coastal protection. Nevertheless, field data are sparse and modeling attempts reveal the need for additional data. This paper presents the results of an extensive field campaign, lasting 6 months, in mangroves along the Andaman coast of Trang Province in southern Thailand. Wave attenuation has been studied along two contrasting transects with different elevation and vegetation characteristics and different orientations towards the Andaman Sea. Along the Kantang transect, which is mostly exposed to swell waves, vegetation densities increased from 4.5 to 9.3 volume-‰ along the transect and on average 63% of the incident wave energy was attenuated over a distance of 246 m. Along the Palian transect, mostly exposed to sea waves instead, vegetation increased from 4.3 to 19 volume-‰ and 72% of the incident wave energy was attenuated over this 98 m transect. It was found that standardized wave attenuation correlates well with incident wave energy, when attenuation is analyzed per vegetation zone. Energy reduction rates of these zones, defined by the gradient of the correlations between the standardized wave attenuation and incident wave energy, are found to increase significantly with vegetation density. Consistently, wave reduction rates, expressing the gradient of the correlation between wave height reduction and incident wave heights, are found to be 0.001-0.014 for the study sites and also show a significant and increasing trend with vegetation densities

Design and Performance Analysis of an Aeronautical Routing Protocol with Ground Station Updates

Aeronautical routing protocol (AeroRP) is a position-based routing protocol developed for highly dynamic airborne networks. It works in conjunction with the aeronautical network protocol (AeroNP). AeroRP is a multi-modal protocol that operates in different modes depending on the mission requirements. Ground station (GS) update mode is an AeroRP mode in which the GS sends geolocation or topology updates to improve routing accuracy. The main contribution of this thesis is to develop and implement the GS updates in AeroRP and analyse its performance in the various modes and compare them against canonical MANET routing protocols such as DSDV, OLSR, AODV, and DSR. The simulation analysis shows that AeroRP outperforms the traditional MANET protocols in various scenarios

Clustering versus SVM for Malware Detection

Previous work has shown that we can effectively cluster certain classes of mal- ware into their respective families. In this research, we extend this previous work to the problem of developing an automated malware detection system. We first compute clusters for a collection of malware families. Then we analyze the effectiveness of clas- sifying new samples based on these existing clusters. We compare results obtained using �-means and Expectation Maximization (EM) clustering to those obtained us- ing Support Vector Machines (SVM). Using clustering, we are able to detect some malware families with an accuracy comparable to that of SVMs. One advantage of the clustering approach is that there is no need to retrain for new malware families

Master of Science

thesisHigh energy materials are commonly used as solid rocket motors propellants. The properties of HE materials can be determined experimentally; however, the hazards associated with experiments on these materials, as well as the costs, make this approach unattractive. The simulations of these materials require techniques that can bridge submicron scales and engineering scales. Micromechanics provides such techniques. The objective of this research is to investigate the effects of stress bridging on predicting the effective properties of high energy materials group. The research focused on polymer bonded explosives (PBXs), since detailed numerical simulations of PBXs are computationally expensive. The generalized method of cells was explored for this research and its predictions of elastic moduli with and without stress bridging. The results show that stress bridging affects the estimated properties considerably. The generalized method of cells without stress bridging is shown to underestimate the elastic moduli of the polymer bonded explosives. Micromechanics analysis requires that the fundamental material properties of the constituents are known initially. The composite material properties can be determined experimentally by testing actual composite specimens. However, in recent years, more and more attention has been given to the development of the analytical and numerical models for predicting composite material properties from the properties of the constituent materials and their relationship to each other. The other part of this research is to identify the Representative Volume Element (RVE) and the boundary conditions for calculation of transverse shear modulus (G23) and then compare the results to the other classical micromechanics solutions. The results show that the proposed approach for identifying the Representative Volume Element (RVE) and the boundary conditions predict as accurately as the other classical micromechanics solutions