The asymmetric exclusion process: Comparison of update procedures

The asymmetric exclusion process (ASEP) has attracted a lot of interest not only because its many applications, e.g. in the context of the kinetics of biopolymerization and traffic flow theory, but also because it is a paradigmatic model for nonequilibrium systems. Here we study the ASEP for different types of updates, namely random-sequential, sequential, sublattice-parallel and parallel. In order to compare the effects of the different update procedures on the properties of the stationary state, we use large-scale Monte Carlo simulations and analytical methods, especially the so-called matrix-product Ansatz (MPA). We present in detail the exact solution for the model with sublattice-parallel and sequential updates using the MPA. For the case of parallel update, which is important for applications like traffic flow theory, we determine the phase diagram, the current, and density profiles based on Monte Carlo simulations. We furthermore suggest a MPA for that case and derive the corresponding matrix algebra.Comment: 47 pages (11 PostScript figures included), LATEX, Two misprints in equations correcte

Efeitos do cloreto de sódio na germinação e vigor de plântulas de arroz.

Este trabalho teve como objetivo avaliar os efeitos delet&ios do NaU na germinação e vigor das cultivares de arroz (Oryza saliva L.) IAC-25, IAC-47, IAC-165, CNA-796019, Lebonnet, IRAT-112 e CICA-8. Amostras de sementes foram colocadas para germinar em solução de NaU com potenciais osmóticos de - 0,4 e - 0,8 Megapascal (MPa). As cultivares IAC-25 e IAC-47 foram consideradas tolerantes à salinidade atá - 0,4 MPa de NaCl; Lebonnet, CNA-796019 e CICA-8 foram consideradas moderadamente tolerantes; a IAC-165 e IRAT-112 pouco tolerantes. Entretanto, a -0,8 MPa, em que todo material foi severamente afetado pela salinidade, as cultivares IAC-25, IAC-47 e CNA-796019 foram as menos sensíveis. A cultivar IAC-25, de maneira geral, foi a mais tolerante à salinidade imposta e a IAC-165 foi a mais sensíve

Charging for Nature: Marine Park Fees and Management from a User Perspective

User fees can contribute to the financial sustainability of marine protected areas (MPAs), yet they must be acceptable to users. We explore changes in the fee system and management of Bonaire National Marine Park (BNMP) from the perspective of users. Responses from 393 tourists indicated that 90% were satisfied with park conditions and considered current user fees reasonable. However, only 47% of divers and 40% of non-divers were prepared to pay more. Diver willingness-to-pay (WTP) appears to have decreased since 1991, but this difference could be due in part to methodological differences between studies. Although current fees are close to diver maximum stated WTP, revenues could potentially be increased by improving the current fee system in ways that users deem acceptable. This potential surplus highlights the value of understanding user perceptions toward MPA fees and management

Assessment of Physical Activity Patterns in Adolescent Patients With Anorexia Nervosa and Their Effect on Weight Gain

(1) Background: Altered physical activity (PA) affects weight recovery in anorexia nervosa (AN) patients. The study aimed to objectively characterize PA patterns and their effect on weight trajectory in adolescent AN patients. (2) Methods: PA was assessed in 47 patients on admission to inpatient treatment, in n = 25 of these patients again 4 weeks after discharge (follow-up, FU), as well as in 20 adolescent healthy controls using the Sense Wear™ armband. The following PA categories were defined by metabolic equivalent (MET) ranges: sedentary behavior (SB), light (LPA), moderate (MPA), vigorous (VPA), and high-level PA (HLPA= MPA + VPA). (3) Results: LPA on admission was significantly higher in AN patients than in controls (103 vs. 55 min/d, p < 0.001), and LPA in AN decreased over time to 90 min/d (p = 0.006). Patients with higher admission LPA (n = 12) still had elevated LPA at FU (p = 0.003). High admission LPA was associated with a higher inpatient BMI percentage gain (ΔBMI%; 18.2% ± 10.0% vs. 12.0% ± 9.7%, p = 0.037) but with a loss of ΔBMI% at FU (-2.3% ± 3.6% vs. 0.8% ± 3.6%, p = 0.045). HLPA at baseline was associated with a lower inpatient ΔBMI% (p = 0.045). (4) Conclusion: Elevated LPA in AN patients decreased after inpatient treatment, and PA patterns had an impact on weight trajectory

Spark plasma sintering of double-walled carbon nanotubes

Bulk samples of double-walled carbon nanotubes are prepared for the first time. The best spark plasma sintering conditions are (1100 °C, 100 MPa). Raman spectroscopy and scanning electron microscopy show that the nanotubes are undamaged. The density is equal to 1.29 g cm−3 and the pores are all below 6 nm in diameter. The electrical conductivity is equal to 1650 S cm−1. The transverse fracture strength is equal to 47 MPa

Pengaruh Penambahan Grafit Terhadap Sifat Tarik, Stabilitas Termal Dan Konduktivitas Listrik Komposit Vinil Ester/Grafit Sebagai Pelat Bipolar Membran Penukar Proton Sel Bahan Bakar (PEMFC)

Sel bahan bakar merupakan sel elektrokimia yang mampu mengkonversi bahan bakar menjadi energi listrik. Lebih dari 80% dari volume, 70% dari total berat dan 60% biaya dalam fuel cell berupa pelat bipolar. Penelitian ini bertujuan untuk mengetahui pengaruh grafit terhadap sifat, stabilitas termal dan konduktivitas listrik komposit vinil ester/grafit. Matriks yang digunakan adalah epoxy vinil ester (EVE) dan novolac vinil ester (NVE). Filler yang digunakan adalah grafit dengan kadar grafit 20 dan 40%. Bahan campuran dimatangkan dalam furnace pada temperatur 50, 100, 150, 200, 250oC selama dua jam. Pengujian yang dilakukan yaitu FT-IR, tarik, SEM, TGA dan konduktivitas listrik. Hasil pengujian menunjukkan penambahan grafit dapat menurunkan Modulus Young, sifat tarik dan elongasi. Kekuatan tarik tertinggi EVE adalah 16.6 MPa sedangkan NVE 10.7 MPa, sedangkan 40% 3.0 MPa untuk EVE dan 2.95 MPa untuk NVE. Stabilitas thermal meningkat dengan penambahan grafit, data 40% grafit menunjukkan berat sisa pada 800⁰ C senilai 47% untuk EVE maupun NVE. Penambahan grafit juga dapat menaikkan konduktivitas listrik. Data tertinggi diperoleh pada komposisi 40% grafit yaitu 1,1 S.Cm-1 untuk EVE dan 0.93 untuk NVE

Quality improvement of manuka honey through the application of high pressure processing

The quality of honey is known to be compromised when it goes through thermal processing due to its negative impact on the unstable and thermolabile honey components which originated from the nectar and bees themselves. This present work is undertaken to access the use of an emerging food preservation technique known as “High Pressure Processing” for treating honey, as an alternative to the conventional thermal processing. In this thesis, honey quality has been addressed by measuring the effects of high pressure processing parameters (pressure, time and temperature) on nutritional properties of honey, namely total phenolic content and antioxidant activity. Honey samples, contained in small pouches, were subjected to different pressures (200-600 MPa) at close to ambient temperatures (25-33°C) for different holding times (10 to 30 min). Thermal processing (49- 70°C) was also carried out for comparison purpose. Results demonstrated that high pressure processing operated at 600 MPa for 10 min has capability to increase significantly the total phenolic content and antioxidant activity by 47% and 30%, respectively. Besides, the result showed that high pressure processing can maintain the natural colour of honey which relates directly to consumer perception, while retaining its shear-thinning behaviour and viscosity with no significant changes (p > 0.05). High pressure processing can also control hydroxymethylfurfural (HMF) concentration in honey during process within the standard limit, 16.93 to 18.76 mg/kg (which is below than the maximum allowed limit of 40 mg/kg). This work also reveals that high pressure processing can enhance antibacterial activity of Manuka honey significantly. It shows an increase in the percentage inhibition of Staphylococcus epidermidis from 64.15 ± 5.86% to 84.34 ± 7.62% when honey was subjected to 600 MPa. Storage studies for one year at room temperature (25°C) demonstrated that high pressure-treated samples have a good retention to the physicochemical, nutritional and rheological properties of honey throughout storage, which confirms that the positive effect of high pressure on honey is not a temporary effect. Whereas, an insight study on the safety part showed that the Saccharomyces cerevisiae cell varied linearly with ° Brix, indicating that food compressibility has a significant role in the microbial inactivation

High-pressure calorimeter chamber tests for liquid oxygen/kerosene (LOX/RP-1) rocket combustion

An experimental program was conducted to investigate the rocket combustion and heat transfer characteristics of liquid oxygen/kerosene (LOX/RP-1) mixtures at high chamber pressures. Two water-cooled calorimeter chambers of different combustion lengths were tested using 37- and 61-element oxidizer-fuel-oxidizer triplet injectors. The tests were conducted at nominal chamber pressures of 4.1, 8.3, and 13.8 MPa abs (600, 1200, and 2000 psia). Heat flux Q/A data were obtained for the entire calorimeter length for oxygen/fuel mixture ratios of 1.8 to 3.3. Test data at 4.1 MPa abs compared favorably with previous test data from another source. Using an injector with a fuel-rich outer zone reduced the throat heat flux by 47 percent with only a 4.5 percent reduction in the characteristic exhaust velocity efficiency C* sub eff. The throat heat transfer coefficient was reduced approximately 40 percent because of carbon deposits on the chamber wall

PROCESSING AND CHARACTERIZATION OF TUBULAR CERAMIC SUPPORT FOR MICROFILTRATION MEMBRANE PREPARED FROM PYROPHYLLITE CLAY

Tubular macroporous support for ceramic microfiltration membranes were prepared by extrusion followed by sintering of the low cost pyrophyllite clay. Clay powders mixed with some organic additives can be extruded to form a porous tubular support. The average pore size of the membrane is observed to increase from 5 µm to 10.8 µm when sintering temperature increase from 900 °C to 1200 °C. However, with the increase in temperature from 900 °C to 1200 °C, the support porosity is reduced from 47% to 30% and flexural strength is increased from 4 MPa to 17 MPa. The fabricated macro-porous supports are expected to have potential applications in the pre-treatment and also can be used like support for membranes of ultra-filtration

Porous Titanium for Biomedical Applications: Evaluation of the Conventional Powder Metallurgy Frontier and Space-Holder Technique

Titanium and its alloys are reference materials in biomedical applications because of their desirable properties. However, one of the most important concerns in long-term prostheses is bone resorption as a result of the stress-shielding phenomena. Development of porous titanium for implants with a low Young’s modulus has accomplished increasing scientific and technological attention. The aim of this study is to evaluate the viability, industrial implementation and potential technology transfer of different powder-metallurgy techniques to obtain porous titanium with stiffness values similar to that exhibited by cortical bone. Porous samples of commercial pure titanium grade-4 were obtained by following both conventional powder metallurgy (PM) and space-holder technique. The conventional PM frontier (Loose-Sintering) was evaluated. Additionally, the technical feasibility of two different space holders (NH4HCO3 and NaCl) was investigated. The microstructural and mechanical properties were assessed. Furthermore, the mechanical properties of titanium porous structures with porosities of 40% were studied by Finite Element Method (FEM) and compared with the experimental results. Some important findings are: (i) the optimal parameters for processing routes used to obtain low Young’s modulus values, retaining suitable mechanical strength; (ii) better mechanical response was obtained by using NH4HCO3 as space holder; and (iii) Ti matrix hardening when the interconnected porosity was 36–45% of total porosity. Finally, the advantages and limitations of the PM techniques employed, towards an industrial implementation, were discussed.Ministry of Economy and Competitiveness of Spain Grant MAT2015-71284-PJunta de Andalucía Grant P12-TEP-1401Comisión Nacional de Investigación, Científica y Tecnológica (CONICYT) of the Chilean government project FONDECYT 1116086