Non-Linear Time Domain Simulation of Moored Floating Systems

This thesis describes the environmental loading and motion response prediction methods of mooring systems. The first chapter presents existing Single Point Mooring Terminals and gives a summary of previous studies carried out on this subject The main objectives of the study are also explained. Finally the structure of the thesis is given. The second chapter is concerned with the motion response prediction of moored buoys. Wave forces acting on the buoy are calculated using Morison's Equation. Catenary equations are utilized to derive cable forces. Two different buoy geometries, cylindrical and conical, are considered in the study. Experimental measurements are compared with time and frequency domain modellings. In the third chapter, diffraction theory used to derive the wave forces is explained. The tanker is modelled as a vertical elliptical cylinder with a finite draught. Calculated wave forces are compared with Oortmerssen's experiments and with the results of a 3-D program developed by Chan. The water depth effect on wave forces is investigated. Program results for various angles of incidence and for different elliptic cylinders are presented. The second order mean force is calculated using the far-field approach, introduced by Maruo. Also the radiation problem of the tanker which is modelled as an elliptical cylinder is solved. Program results are compared with Oortmerssen's experiments and with Chan's 3-D program results. Program results for different cylinders and for different water depth/draught ratios are presented. Chapter 4 describes a time domain model used to predict the motion responses of a tanker-buoy system under wave, wind and current loading. Motion equations of the tanker-buoy system are derived by using Cummins' method. Frequency-independent hydrodynamic coefficients and time histories of wave forces in irregular seas are calculated. Experimental measurements are compared with the time domain simulation results. Chapter 5 presents the results of a series of parametric studies. A computer program developed to predict the motion responses of the coupled tanker-buoy system is run for different parameters, such as; wave, wind and current angle of attacks, wind and current speed, elasticity of the mooring lines and the hawser line, buoy and tanker geometry, water depth, draught of the ship. Numerical aspects of the program, such as the solution of the differential equations and the evaluation of the convolution integral are discussed. In chapter 6 a description of model tests performed in regular waves is presented. Two sets of experiments are conducted. The first set of experiments aims to predict the motion responses of conical and cylindrical buoys, the second to predict the motion responses of the tanker-buoy system and the hawser line forces. In the final chapter general conclusions are drawn and some recommendations for future work are made

Emergency crowd simulation for outdoor environments

Cataloged from PDF version of article.We simulate virtual crowds in emergency situations caused by an incident, such as a fire, an explosion, or a terrorist attack. We use a continuum dynamics-based approach to simulate the escaping crowd, which produces more efficient simulations than the agent-based approaches. Only the close proximity of the incident region, which includes the crowd affected by the incident, is simulated. We use a model-based rendering approach where a polygonal mesh is rendered for each agent according to the agent's skeletal motion. To speed up the animation and visualization, we employ an offline occlusion culling technique. We animate and render a pedestrian model only if it is visible according to the static visibility information computed. In the pre-processing stage, the navigable area is decomposed into a grid of cells and the from-region visibility of these cells is computed with the help of hardware occlusion queries. (C) 2009 Elsevier Ltd. All rights reserved

Initial stages of gravity-driven flow of two fluids of equal depth

Short-time behavior of gravity-driven free surface flow of two fluids of equal depth and different densities is studied. Initially, the fluids are at rest and separated with a vertical rigid plate of negligible thickness. Then, the plate disappears suddenly and a gravity-driven flow of the fluids starts. The flow in an early stage is described by the potential theory. The initial flow in the leading order is described by a linear problem, which is solved by the Fourier series method. The motions of the interface between the fluids and their free surfaces are investigated. The singular behaviors of the velocity field at the bottom point, where the interface meets the rigid bottom, and the top point, where the interface meets both free surfaces, are analyzed in detail. The flow velocity is shown to be log-singular at the bottom point. The leading-order inner asymptotic solution is constructed in a small vicinity of this point. It is shown that the flow close to the bottom point is self-similar. The motion of the interface is independent of any parameters, including the density ratio, of the problem in specially stretched variables. In the limiting case of negligible density of one of the fluids, the results of the classical dam break problem are recovered. The Lagrangian representation is employed to capture the behavior of the interface and the free surfaces at the top, where the fluid interface meets the free surfaces. The shapes of the free surfaces and the interface in the leading order computed by using the Lagrangian variables show a jump discontinuity of the free surface near the top point where the free surfaces and the interface meet. Inner region formulation is derived near the top point

Effect of nitrogen gas flushing treatments on total antioxidant capacity and ascorbic acid content in raw bovine milk during cold storage

Continuous nitrogen gas (N-2) flushing extends the shelf life of raw milk (RM) during cold storage. The effect of N-2 treatment on the total antioxidant capacity (TAC) and ascorbic acid (AA) content of RM was determined during cold storage. TAC of RM or deproteinized RM was determined by ABTS and DPPH methods, while L(+)-AA content of RM was determined chromatographically on days 0, 4 and 7 during storage at 6 +/- 1 degrees C. With the ABTS method, the TAC of RM decreased from 472.33 +/- 16.70 to 369.47 +/- 62.06 mu M TEAC while it reduced from 13.30 +/- 0.84 to 8.20 +/- 0.66 mu M TEAC with DPPH method during cold storage. TAC of RM determined with ABTS method decreased after 4 day-storage; however, they remained statistically similar for N-2-treated samples during 7 day-storage. The AA content of RM ranged from 14.06 to 10.76 mg/L during storage but N-2-treatment did not influence AA content significantly. Deproteinization reduced TAC values of milk samples significantly, and the reduction with the ABTS method was about 47.50 % for control samples cold-stored for four days, while it was 11.67 % for N-2-treated deproteinized RM. In conclusion, N-2-flushing through the headspace of milk containing vessels showed a significant protective effect on the antioxidant components of RM during cold storage.Peer reviewe

ISI-aware channel code design for molecular communication via diffusion

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.In molecular communication via diffusion, information molecules diffusing in the environment are subject to Brownian motion. Due to probabilistic propagation, the arrival of the molecules at the receiver is spread in time, leading to the reception of some molecules belonging to the previous symbol(s) during the upcoming symbol duration. Known as inter-symbol interference (ISI), this problem has been extensively studied in the literature by applying a large spectrum of techniques, mostly inspired by approaches in the wireless communication domain, including channel coding techniques. Unfortunately, many known channel codes do not perform well in the molecular communications domain since the diffusion channel features a significant memory component. In this paper, novel methods for channel coding by incorporating the effect of ISI in the design of the channel codes for the molecular diffusion channel are proposed. The results show that the proposed methods provide significant improvements in performance in terms of the codeword error rate.Postprint (author's final draft

Total antioxidant capacity and phenolic content of pasteurized and UHT-treated cow milk samples marketed in Turkey

Peer reviewe

Polymerase chain reaction of enterococcus faecalis and candida albicans in apical periodontitis from Turkish patients

Aim: The aim of this study was to determine the frequency of two important pathogenic microorganisms associated with endodontic infections, Enterococcus faecalis and Candida albicans, in root canal samples from patients with necrotic pulps or failed canal therapy by polymerase chain reaction method. Methodology: Microbial samples were obtained from 117 teeth with necrotic pulp tissues and 114 teeth with failed endodontic treatment. Results: E.faecalis were identified in 16% of the necrotic and 10% of the retreated root canal infections by PCR. C.albicans genome were identified in 20% and 11% of the necrotic and retreated root canal infections, respectively, by PCR. The frequencies of microbiota were not statistically different between necrotic and retreatment groups (p > 0.05, chi squared test). Conclusions: PCR analysis of teeth with periapical lesions revealed that E.faecalis was found in fewer patients than in previous studies. The C.albicans prevelance was consistent with previous reports. No statistical difference was found between primary and secondary root canal infections for C.albicans or E.faecalis

In vitro susceptibility of e.faecalis and c.albicans isolates from apical periodontitis to common antimicrobial agents, antibiotics and antifungal medicaments

The aim of this study was to evaluate in vitro antimicrobial activity of 4 antibiotic agents (for E.faecalis) and 4 antifungal agents (for C.albicans) by agar dilution method. Additionally, modified strip diffusion method was used for detection of in vitro antimicrobial activities of 5% NaOCl, 2.5% NaOCl, 17% EDTA and 2% CHX and agar diffusion method for detection of in vitro susceptibilities of three intracanal medicaments for 18 E.faecalis and 18 C.albicans isolates from primary and secondary root canal infection. Isolates were recovered from 231 endodontic samples of patients, with the need of root canal treatment and retreatment. All tested E.faecalis isolates showed resistance to antibiotics. For irrigation solutions, 2% CHX was more effective in eliminating E.faecalis but 5% NaOCl showed larger inhibition zone than 2.5% NaOCl, 17% EDTA and 2% CHX. For intracanal medication, Ca(OH)2-CHX worked efficiently in killing E.faecalis isolates compared to Ca(OH)2-Steril saline solution, Ca(OH)2-Glycerin. For C.albicans, 18 isolates were susceptible to amphotericin B, nistatin, fluconazole but showed resistance to ketoconazole. 5% NaOCl was more effective in eliminating and produced larger inhibition zone compared to 2.5% NaOCl, 17% EDTA and 2% CHX. Ca(OH)2-Glycerin intracanal medication was better in eliminating C.albicans isolates and produced larger inhibition zone compared to other Ca(OH)2 medicaments

Odabir autolitičkih bakterija mliječne kiseline kao mogućih starter kultura za ubrzavanje zrenja sireva u salamuri

The aim of this study was to select lactic acid bacteria (LAB) having autolytic activity on the basis of the technological aspects to accelerate the ripening of white-brined cheeses. For this purpose, mesophilic (n=526) and thermophilic (n=413) LAB isolates were collected from 34 raw milk and 16 cheese samples. 27 LAB isolates with a high autolytic activity ranging from 34 to 54 % were identified by (GTG)5 fingerprint and 16S rDNA sequence analyses, which showed that Lactococcus lactis and Enterococcus faecium were abundant among the autolytic isolates in raw milk while E. faecium and Lactobacillus casei were in white-brined cheese. The autolysis rate of LAB strains increased by raising the temperature and pH; however, decreased somewhat at high NaCl concentrations. Additionally, the highest autolysis was observed in the presence of glucose for most of the strains. On the other hand, Lb. plantarum PFC231 was autolyzed differently, being the highest in the presence of lactose. E. durans PFC235, E. faecium PFC232 and Lb. plantarum PFC231 were autolyzed more than other LAB strains, when exposed to low pH, high NaCI concentration at 10 °C simultaneously. However, only Lb. plantarum PFC231, Leuconostoc mesenteroides PFC234, Lc. lactis subsp. cremoris PFC233, Pediococcus acidilactici PFC237 and Lb. rhamnosus PFC238 were able to show intracellular caseinolytic activity. In conclusion, Lb. plantarum PFC231 has the potential to be used as an adjunct starter culture in the production of white-brined cheeses because of its autolysis at low temperature, pH and high salt concentrations, as well as intracellular caseinolytic activity.Cilj ovog rada bio je odabrati bakterije mliječne kiseline (LAB) koje imaju autolitičku aktivnost, kako bi se upotrebljavale za ubrzavanje procesa zrenja sireva u salamuri. U tu svrhu je iz 34 uzorka sirovog mlijeka te 16 uzoraka sira izolirano 526 mezofilnih i 413 termofilnih sojeva LAB. Primjenom 16SrDNA analize sekvenci i (GTG)5 metode otiska prsta izolirano je ukupno 27 sojeva s autolitičkom aktivnošću koja se kretala između 34 i 54 %. Pritom su se najdominantnijim autolitičkim vrstama u sirovom mlijeku pokazali Lactococcus lactis i Enterococcus faecium, dok su u siru prevladavali Enterococcus faecium i Lactobacillus casei. Stupanj autolize sojeva LAB rastao je s porastom temperature i pH, dok je opadao pri povišenim koncentracijama NaCl. Nadalje, kod svih sojeva je najveća autoliza zabilježena uz prisutnost glukoze. Međutim, soj Lb. plantarum PFC231 ovdje se izdvajao, pokazujući najveću autolizu u prisutnosti laktoze. Sojevi E. durans PFC235, E. faecium PFC232 i Lb. plantarum PFC231 su pri izloženosti niskom pH i visokoj koncentraciji NaCl pri 10 °C pokazivali viši stupanj autolize u odnosu na ostale sojeve. Međutim, samo su sojevi Lb. plantarum PFC231, Leuconostoc mesenteroides PFC234, Lc. lactis subsp. cremoris PFC233, Pediococcus acidilactici PFC237 i Lb. rhamnosus PFC238 pokazali sposobnost unutarstanične hidrolize kazeina. Zaključno, soj Lb. plantarum PFC231 jedini je pokazao potencijal za upotrebu kao starter kultura u proizvodnji sireva u salamuri, budući da ima autolitičku aktivnost pri niskim temperaturama i pH vrijednosti, te visokoj koncentraciji soli, a pokazao je i sposobnost unutarstanične hidrolize kazeina

Parkinson’s Disease and Narcolepsy-Like Sleep Episodes

A fifty one-year-old male patient presented with the complaint of sudden daytime sleep episodes for the last one and a half years. The patient had been diagnosed with Parkinson’s disease for four years and has been administered treatment of ropinirole 4 mg XL and rasagiline 1 mg tablet. The patient reported that his complaints occurred with the addition of pramipexola 0.750 mg/day tablet. Excessive daytime sleepiness occurred as sudden sleep episodes without giving any prior signs and subsided spontaneously after which the patient felt rested. The patient was diagnosed with severe obstructive sleep apnea syndrome and hypersomnia depending on medical disease and drug side effects with polysomnography and multiple sleep latency test