In this thesis we employ computer simulations and statistical physics to understand the origin of liquid-liquid phase transitions and their relationship with anomalies typical of liquid water. Compared with other liquids, water has many anomalies. For example the density anomaly: when water is cooled below 4 C the density decreases rather than increases. This and other anomalies have also been found to occur in a few other one-component liquids, sometimes in conjunction with the existence of a liquid-liquid phase transition (LLPT) between a low-density liquid (LDL) and a high-density liquid (HDL). Using simple models we explain how these anomalies arise from the presence of two competing length scales. As a specific example we investigate the cut ramp potential, where we show the importance of "competition" in this context, and how one length scale can sometimes be zero. When there is a clear energetic preference for either LDL or HDL for all pressures and temperatures, then there is insufficient competition between the two liquid structures and no anomalies occur. From the simple models it also follows that anomalies can occur without the presence of a LLPT and vice versa. It remains therefore unclear if water has a LLPT that ends in a liquid-liquid critical point (LLCP), a hypothesis that was first proposed based on simulations of the ST2 water model. We confirm the existence of a LLCP in this model using finite size scaling and the Challa-Landau-Binder parameter, and show that the LLPT is not a liquid-crystal transition, as has recently been suggested. Previous research has indicated the possible existence of a LLCP in liquid silica. We perform a detailed analysis of two different silica models (WAC and BKS) at temperatures much lower than was previously simulated. Within the accessible temperature range we find no LLCP in either model, although in the case of WAC potential it is closely approached. We compare our results with those obtained for other tetrahedral liquids and conclude that insufficient "stiffness" in the Si-O-Si bond angle might be responsible for the absence of a LLCP.

The aim of thesis is a system of critical points in food production, especially in the production of confectionery products. The system is based on the ability of manufacturers to establish the critical aspects of the production of safe food, allows to systematically identify hazards and assess the probability of its occurrence during production. Danger primarily as a substance in food, which could result in adverse health effects for consumers. And subsequently helps to improve the effectiveness of controls. This concept of control techniques is apparented from the national and European legislative requirements, which are listed in the first theoretical part of this thesis. They are designed to better acquaint themselves with the general requirements that are placed on food manufacturers. With the entry into the European Union is integrated European legislation, national legislation incorporated in European policy and legal requirements are taken into national legislation the second part introduces the principles and procedures of the system of critical points. Many manufacturing processes involve multi-process from producing raw materials for the finished product. Correct, complete, and introduced the study of critical points identified by the system and regulate the factors that directly affect the safety of products. Identification and monitoring of critical points is more cost effective than the method of quality assurance inspection and testing of finished product. Records and documentation are the perfect evidence that all measures have been taken and were given the duty of care to prevent problems. In the final section is a common procedure for a system of critical points compared with an established system for a particular product. The specific products will be demonstrated readiness and capacity of the undertaking to establish a system for all products or product groups, which will subsequently be evaluated. The purpose of thesis is carefully and thoroughly analyze the system by the critical points in the manufacture of confectionery, but prove that we are able to prepare for the strict legal conditions and the hard and fierce competition. This development does not stop or avoid it, have no other than to respond promptly to these developments and to adapt in order to produce the desired changes brought about by the success and to our food industry was at a level as we wish, but also as your own work and creativity deserve. Not in vain proverb holds that "Happiness wishes prepared.

This dissertation was to study computational theory and methods for ?nding multiple saddle critical points in Banach spaces. Two local minimax methods were developed for this purpose. One was for unconstrained cases and the other was for constrained cases. First, two local minmax characterization of saddle critical points in Banach spaces were established. Based on these two local minmax characterizations, two local minimax algorithms were designed. Their ?ow charts were presented. Then convergence analysis of the algorithms were carried out. Under certain assumptions, a subsequence convergence and a point-to-set convergence were obtained. Furthermore, a relation between the convergence rates of the functional value sequence and corresponding gradient sequence was derived. Techniques to implement the algorithms were discussed. In numerical experiments, those techniques have been successfully implemented to solve for multiple solutions of several quasilinear elliptic boundary value problems and multiple eigenpairs of the well known nonlinear p-Laplacian operator. Numerical solutions were presented by their pro?les for visualization. Several interesting phenomena of the solutions of quasilinear elliptic boundary value problems and the eigenpairs of the p-Laplacian operator have been observed and are open for further investigation. As a generalization of the above results, nonsmooth critical points were considered for locally Lipschitz continuous functionals. A local minmax characterization of nonsmooth saddle critical points was also established. To establish its version in Banach spaces, a new notion, pseudo-generalized-gradient has to be introduced. Based on the characterization, a local minimax algorithm for ?nding multiple nonsmooth saddle critical points was proposed for further study.

This dissertation was to study computational theory and methods for ?nding multiple saddle critical points in Banach spaces. Two local minimax methods were developed for this purpose. One was for unconstrained cases and the other was for constrained cases. First, two local minmax characterization of saddle critical points in Banach spaces were established. Based on these two local minmax characterizations, two local minimax algorithms were designed. Their ?ow charts were presented. Then convergence analysis of the algorithms were carried out. Under certain assumptions, a subsequence convergence and a point-to-set convergence were obtained. Furthermore, a relation between the convergence rates of the functional value sequence and corresponding gradient sequence was derived. Techniques to implement the algorithms were discussed. In numerical experiments, those techniques have been successfully implemented to solve for multiple solutions of several quasilinear elliptic boundary value problems and multiple eigenpairs of the well known nonlinear p-Laplacian operator. Numerical solutions were presented by their pro?les for visualization. Several interesting phenomena of the solutions of quasilinear elliptic boundary value problems and the eigenpairs of the p-Laplacian operator have been observed and are open for further investigation. As a generalization of the above results, nonsmooth critical points were considered for locally Lipschitz continuous functionals. A local minmax characterization of nonsmooth saddle critical points was also established. To establish its version in Banach spaces, a new notion, pseudo-generalized-gradient has to be introduced. Based on the characterization, a local minimax algorithm for ?nding multiple nonsmooth saddle critical points was proposed for further study.

The overall purpose of the study was to get a deeper understanding of the process of transition from preschool to compulsory school. According to the purpose the study three issues are the following: 1. How organized the reception to the compulsory school? 2. The motives are to host the compulsory school? 3. What consequences may mean the individual, group and organizational level? The background of the study highlights different factors that influence the transition between pre-school and compulsory school. Also included is a review of research on studies related to students experiences of being in compulsory school and wc alternative solutions which occurred out in the operations, which are relevant for the study. Semi-structured interviews were conducted with eight managers /principals and special educators. The result is divided into four themes. The result in part one includes enrollment processes for compulsory school. Part two describes the reasons for the receipt of compulsory school. The third part shows the impact on the individual group and organizational level. The fourth section deals with children and carers influence and participation. The discussion raised that since the new Education Act (Lgr 11) it is clear who belongs compulsory school and who do not. It requires a diversity of actors that work together to facilitate the transition process for children/ students.

HACCP ( Hazard Analysis and Critical Control Points ) is a science-based system of food safety. This system identifies hazards and risks in food production and it proposes an effective control and monitoring procedures at points that are critical for food safety . In cases where e.g. measured values ( temperature, time) deviates from the set limits are performed specific corrective measures. Within this system of protection of food safety Two critical control points(CCP)were established in selected company and they have been set correctly . Two checkpoints (CP )in HACCP weren´t determined completely so newly designed and in five cases recommended modifications , including one designed to change the compliance time and once in imminent danger .

Submitted by ANA KARLA PEREIRA RODRIGUES (anakarla_@hotmail.com) on 2017-08-23T12:41:56Z No. of bitstreams: 1 arquivototal.pdf: 3952391 bytes, checksum: 515d42b8a346d93bfff74862f9c40c46 (MD5) / Made available in DSpace on 2017-08-23T12:41:56Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 3952391 bytes, checksum: 515d42b8a346d93bfff74862f9c40c46 (MD5) Previous issue date: 2016-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / In this work we first study some interesting generalizations of the famous inequality Sobolev to limited domains. Then, we will study the existence of positive solution for a nonlinear elliptic equation on a certain condition Neumann, by imposing certain restricitive condition in the nonlinearity. To we consider more general hypotheses we will assume conditions on the boundary of domain. / Neste trabalho, estudaremos primeiramente algumas generaliza¸c˜oes interessantes da famosa desigualdade de Sobolev para dom´ınios limitados. Em seguida, iremos estudar a existˆencia de solu¸c˜oes positivas para uma equa¸c˜ao el´ıptica n˜ao linear, sob uma certa condi¸c˜ao de Neumann e impondo algumas condi¸c˜oes restritivas sobre a n˜ao linearidade. Para considerarmos hip´oteses mais gerais, assumiremos condi¸c˜oes na fronteira do dom˜Anio.

Diploma thesis focuses on the analysis of critical points in the transport of hazardous materials on the basis of which there is given a methodology for selecting safe routes. Thethesis includes statistical data on the total performance in the transport of hazardous materials within the EU states as well as specifies the proportion of transport performance of hazardous materials to the total performance among the individual European countries. For Czech Republic, the thesis also presents a statistical overview of the accident rate associated with this kind of transport as well as deals with the causes and consequences of the accidents occured during the transportation.

Thesis advisor: Kevin S. Bedell / We present several results based upon non-trivial extensions of Landau-Fermi liquid theory. First proposed in the mid-20th century, the Fermi liquid approach assumes an adiabatic “switching-on” of the interaction, which allows one to describe the collective excitations of the many-body system in terms of weakly-interacting quasiparticles and quasiholes. At its core, Landau-Fermi liquid theory is often considered a perturbative approach to study the equilibrium thermodynamics and out-of-equilibrium response of weakly-correlated itinerant fermions, and therefore non-trivial extensions and consequences are usually overlooked in the contemporary literature. Instead, more emphasis is often placed on the breakdown of Fermi liquid theory, either due to strong correlations, quantum critical fluctuations, or dimensional constraints. After a brief introduction to the theory of a Fermi liquid, I will first apply the Landau quasiparticle paradigm to the theory of itinerant Majorana-like fermions. Defined as fermionic particles which are their own anti-particle, traditional Majorana zero modes found in topological materials lack a coherent number operator, and therefore do not support a Fermi liquid-like ground state. To remedy this, we will apply a combinatorical approach to build a statistical theory of self-conjugate particles, explicitly showing that, under this definition, a filled Fermi surface exists at zero temperature. Landau-Fermi liquid theory is then used to describe the interacting phase of these Majorana particles, from which we find unique signatures of zero sound in addition to exotic, non-analytic contributions to the specific heat. The latter is then exploited as a “smoking-gun” signature for Majorana-like excitations in the candidate Kitaev material Ag3LiIr2O6, where experimental measurements show good agreement with a sharply-defined, “Majorana-Fermi surface” predicted in the underlying combinatorial treatment. I will then depart from Fermi liquid theory proper to tackle the necessary conditions for the applicability of Luttinger’s theorem. In a nutshell, Luttinger’s theorem is a powerful theorem which states that the volume of phase space contained in the Fermi surface is invariant with respect to interaction strength. In this way, whereas Fermi liquid only describes fermionic excitations near the Fermi surface, Luttinger’s theorem describes the fermionic degrees of freedom throughout the entire Fermi sphere. We will show that Luttinger’s theorem remains valid only for certain frequency and momentum-dependencies of the self-energy, which correlate to the exis- tence of a generalized Fermi surface. In addition, we will show that the existence of a power-law Green’s function (a unique feature of “un-particle” systems and a proposed characteristic of the pseudo-gap phase of the cuprate superconductors) forces Luttinger’s theorem and Fermi liquid theory to be mutually exclusive for any non-trivial power of the Feynman propagator. Finally, we will return to Landau-Fermi liquid theory, and close with novel out-of-equilibrium behavior and stability in unconventional Fermi liquids. First, we will consider a perfectly two- dimensional Fermi liquid. Due to the reduction in dimension, the traditional mode expansion in terms of Legendre polynomials is modified to an expansion in terms of Chebyshev polynomials. The resulting orthogonality conditions greatly modifies the stability and collective modes in the 2D system. Second, we will look at a Fermi liquid in the presence of a non-trivial gauge field. The existence of a gauge field will effectively shift the Fermi surface in momentum space, resulting in, once again, a modified stability condition for the underlying Fermi liquid. Supplemented with a modernized version of Mermin’s condition for the propagation of zero sound, we outline the full effects a spin symmetric or anti-symmetric gauge would have on a Fermi liquid ground state. / Thesis (PhD) — Boston College, 2021. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Physics.

The aim of this paper was to investigate whether infrastructure could be modelled in order to find critical points using network science and graph theory. Since a lot of information about ourinfrastructures is publicly available, an attacker might exploit this to find vulnerabilities in our systems. With that in mind, the methods of this paper were implemented from an attackers point of view who’d want to maximize harm with minimal effort. The Swedish railway network served as an example and starting point for the optimization of the methods. The data for the network was obtained from the Swedish Transport Agency’s website and was implemented in Networkx using Python. Different centrality metrics were used to identify and remove critical nodes in the network. The centrality metrics were also used to rank the nodes and to remove them after order of importance as the size of the largest component was recorded. This was done both with no recalculation and with a recalculation after each removal. The results were compared with the random removal of nodes, and it showed that without a recalculation the random removal performed better but with recalculation all the centrality metrics performed significantly better. The Swedish railway network is a sensitive network in terms of how it is connected. Targeting a few nodes could completely cut off parts of the graph, creating two sub components with no way of traveling between them. Many different methods can identify these nodes, but only a few are suitable in terms of generic results that could work on other networks as well. The most prominent one being the one dealing with degree and connectivity. The nodes that had a higher degree than connectivity between themselves and the source, identified nodes that would completely disrupt the network, leaving two subcomponents. Infrastructures can be seen as highly intertwined systems, where the physical-, cyber- and human parts all affect and interact with each other.