The doctrine that the content of the conclusion of a deductively valid argument is included in the content of its premises, taken jointly, is a familiar one. It has important consequences for the question of what value valid arguments possess, since it indicates the poverty of three traditional answers: that arguments may and should be used as instruments of persuasion, that they may and should be used as instruments of justification; and that they may and should be used to advance knowledge. The truth is, however, that in each of these cases the argument has only a managerial role and, if there is any work done, it is the premises that do it. It will be maintained that this point has little force against the critical rationalist answer, which I shall defend, that the principal purpose of deductive reasoning from an assemblage of premises is the exploration of their content, facilitating their criticism and rejection. That said, the main aim of the present paper is not to promote critical rationalism but to consider some published objections to the doctrine that a statement asserts every statement that is validly deducible from it. The alleged counterexamples to be considered fall roughly into two groups: statements that emerge with time from a rich mathematical or empirical theory, but were originally unformulated and are deducible from the theory only in a non-trivial way (Frederick 2011, 2014; Williamson 2012); and statements, notably disjunctions, that are easily formulated and are deducible from a theory in a trivial way (Schurz & Weingartner 1987; Mura 1990, 2008; Gemes 1994; Yablo 2014). Each of these counterexamples will be evaluated and dismissed.

Background The change in venous oxygen saturation occurs earlier, and even its reduction is faster than arterial oxygen saturation. The aim of this study was to validate SvO2 and PvO2 for O2 content measurement in children hospitalized with respiratory distress. Materials and Methods In this cross-sectional study, 80 children who were admitted with respiratory distress were included in the study according to the study inclusion and exclusion criteria. Baseline characteristics such as age and gender were recorded in the data collection form, designed by the researcher. In order to determine the amount of SaO2 and PaO2 the arterial blood sample was prepared, venous blood sample was prepared to determine the amount of hemoglobin, SvO2 and PvO2. The gold standard for the determination of O2 content was the arterial blood sample. All samples were examined by a blood gas analyzer and then calculated using the formula of O2 content values. For SvO2 and PvO2 validation, we used diagnostic analysis methods including sensitivity, specificity, positive and negative predictive values. Cut-point value for SvO2 and PvO2 were 76. 50 and 44. 30, respectively. Results In this study, the patients’ mean age was 5. 15 ± 4. 20 years. 62. 5% (n=50) were male and 38. 5% (n=30) were female. The values of arterial and venous O2 content were 14. 13 ± 3. 05 and 11. 95 ± 3. 04 from a total of 80 patients. SvO2 and PvO2 for measuring O2 content had a sensitivity of 80. 5 and 71. 80%, respectively, and specificity of 80. 5 and 78%, respectively. Conclusion SvO2 and PvO2 have good validity for evaluating O2 content in patients admitted to PICU. So that SvO2 had a sensitivity and specificity of over 80%, and PvO2 had a sensitivity and specificity of over 70%.

Introduction: FMRI is a new approach in MRI to provide functional data of human brain activities. Some methods such as BOLD contrast, perfusion imaging, diffusion imaging, and spectroscopy in MRI have used to yield functional images.Material and Methods: This research was performed in imaging center of IMAM KHOMEINI hospital in TEHRAN in 1997. The experiments were performed on a conventional 1.5- T picker MR instrument, using a standard head coil. CE – FAST gradient echo images were obtained (TR=100, TE = 35, 128*256 matrix, 10 mm slice, FOV = 250 mm, F.A =25 Degree, NEX = 1, 13 s per image). Images were obtained during sensory - motor stimulation by pressing fingers to each other, coronal oblique images were acquired through central sulcus (precentral gyrus) where the related sensory cortex is. Then, the Images were transferred to personal computers in order to eliminate noise and highlight the functional differences. These images were processed by various mathematical methods such as subtraction and student T- test.Results: Although some changes were seen in functional area, there were not significant results by the conventional system protocols. Some new protocols were designed and implemented to increase the sensitivity of the system to functional changes.Discussion: However, more research needs to be done in the future to obtain faster and more efficient techniques and in regard to clinical applications of the method.

This paper reports a CFD modeling study on the possibility of using high temperature and low oxygen content exhaust gases as oxidant for combustion in an industrial furnace by a written computer program. Under these conditions, the predicted results for the flow and heat transfer properties are compared with those under the several cases of conventional and highly preheated and diluted air combustion (HPDAC) conditions. Although the calculation procedure is a two dimensional one with the vorticity and stream function as the main hydrodynamic variables; its results can yet be also valid for the three dimensional case. Because of the weakness of the standard or other traditional k-e models in predicting the spreading rate of axisymmetric jets, and also for the sake of economy and lack of boundary conditions, here the turbulent transport properties are obtained from an algebraic formula. An infinitely single-step chemical reaction (physically controlled) and a model known as "four flux" are considered as combustion and radiation models, respectively. The qualitative and quantitative verification of high temperature and low oxygen content air/exhaust gases combustions and conventional (low and high air temperature) combustions results have been checked and compared, respectively, with those reported in the literature. Finally, in this investigation three modified concepts and new formulas have been proposed and used to define the gas temperature uniformity, the chemical flame size and the maximum flame temperature as the HPDAC’S main unique features achievement criteria.

The possible ductility troughs of tough pitch copper containing various oxygen contents were identified to determine the safe and unsafe thermomechanical processing domains. Tensile and compression tests were conducted in temperature range of 300-800°, C. The critical strain of single/multiple peaks dynamic recrystallization decreased by increasing oxygen content up to 220 ppm, and again increased with further increment up to 390 ppm. The non-uniform elongation region increased by increasing the temperature, and above 500°, C, it was the dominant portion of the tensile curves. The long post-uniform elongation was attributed to the occurrence of dynamic recrystallization which increased the resistance of the material to localized necking. Two ductility troughs (unsafe thermomechanical processing regions) were recognized at temperatures of 400±, 50°, C and 600±, 50°, C. The ductility drop regions shifted to lower temperatures with an increase in the strain rate. The variation of the oxygen content, however, did not have significant effects on the position of ductility drops. The current work also explores the fracture surface characteristics of the tensile tested specimens.

The influence of initial moisture content on wood decay at different levels of atmospheric oxygen concentration was studied. Three fungi, Coriolus versicolor (C. versicolor) a white rot, Coniophora puteana (C. puteana) a brown rot, and Chaetomium globosum (C. globosum) a soft rot, were chosen. The mycelia of the fungi were inoculated in to mini blocks of Fagus sylvatica (beech) and Pinus sylvestris (Scots pine). Incubation was conducted under four levels of oxygen concentration (1,5,10, and 21% O2) at 22o C. At low oxygen concentrations, an increase of moisture content had a negative effect on the wood decay process by both the Basidiomycetes (C. versicolor and C. puteana) in Scots pine and beech. In air, the effect of initial moisture content on wood decay by these fungi depended on the characteristics of the fungi and the wood species (such as fungal biology and physiology). When C. globosum was used as a colonizer, increasing moisture content generally increased weight loss in the wood blocks (especially in beech). When the moisture content in the wood blocks was increased, more sporulations by C. globosum were also observed on the wood samples. However, the role of oxygen in inceasing wood decay was more important than the moisture content effect.

Rotating detonation engines (RDEs) are an advanced propulsion technology utilizing detonation combustion. RDEs have shown significant potential for substantially enhancing the performance of conventional propulsion systems due to their inherent advantages such as rapid energy release, high thermal efficiency, and a compact reaction zone. Based on these strengths, we conducted experimental investigations of a disk-shaped rotating detonation engine to examine the influences of the oxygen content on the operation characteristics of the engine. The results demonstrate that oxygen enrichment significantly altered the evolution process of rotating detonation waves (RDWs), with dual-wave modes exhibiting higher initiation probability under oxygen-enriched conditions. The results of a quantitative analysis revealed that increasing oxygen content of 21% to 30% increased the velocity of the detonation wave by 11-17% for a single-wave mode and 5-7% for a dual-wave mode. The results of parametric studies demonstrate that increased mass flow rate enhanced the propagating stability of rotating detonation waves, which reduced fluctuations in their parameters. Increasing oxygen content conversely decreased the RDWs’ propagation stability, particularly at low flow rates in single-wave mode. Increasing the oxygen content facilitated the formation of multiple waves, which reduced critical mass flow rate as well as the lean limit of the equivalent ratio for multi-wave modes. Furthermore, oxygen enrichment markedly diminished the lean limit of engine’s operation equivalent ratio, which broadened the stable operating envelope. In contrast with pure air, the lean operation limit of equivalent ratio declined by roughly 25%-59% under oxygen-enriched air conditions. The results of this study demonstrate that oxygen content critically influences the RDWs’ propagation mode in disk-shaped structure as well as the parameters of the detonation waves and the engine’s operation envelope of the engine. These findings offer a deeper understanding of rotating detonation wave propagation and establish a foundation for advancing rotating detonation combustion applications.

Extended AbstractIntroductionWater quality changes with the penetration of water from the surface of the earth to the subsurface layers, which are accompanied by the passage of subsurface of earth crust with different chemical composition. The most important issues is the increase in the concentration of iron and manganese. Therefore, almost underground water sources have significant amounts of iron and manganese. At high concentrations, those may cause the growth of iron and manganese bacteria, increase pathogenic microorganisms, create bitter taste and unpleasant smell in water, create red and brown spots on appliances and blockage water distribution systems. One of the main steps in the water purification process is the removal of iron and manganese ions. Among these methods, the use of oxidation is more widely used due to less operational costs. Use of an aerator is the main part of this method. Stepped weirs are one of the economical devices for the aeration of water that has acceptable performance. In this research, application of a pyramid-shaped stepped weir with and without sill on increase the dissolved oxygen concentration under various flow discharge was investigated experimentally.  Experimental Setup and procedureExperiments have been carried out on a stepped-pyramidal weir model in the Hydraulic Modeling Laboratory at of University of Guilan. The physical model of the stepped-pyramid weir is made of PVC panels with a constant slope of 1: 2 and the number of steps is 6, with dimensions of 4 cm high and 8 cm long. The weir was installed on Iron’s tank with dimensions of 1. 5 m length and 1. 5 m in width and 1 m height. A centrifugal pump device with maximum flow rate of 8 l/s was used to provide desired flow discharge. In order to measure the flow rate, an ultrasonic flow meter was used with an accuracy of ±0. 01 l/s. In each geometry of the weir and desired flow rate, first the concentration of dissolved oxygen in the water supply tank was reduced to 2 mg/l using Na2SO3 solution, then variation of dissolved oxygen concentration was measured by 2 oxygen meters (DO meter) model AL20Oxi manufactured by Aqualytic company, which was installed on both sides of the tank, until the dissolved oxygen concentration reached on its initial level. In this research, totally 30 tests were carried out to consider effect of the stepped-pyramidal weir on increasing the dissolved oxygen concentration.  Results and discussionThe performance of stepped-pyramidal weirs with different geometries at h/yc equal to 7. 4 (flow discharge of 2 l/s) for the first step indicates that for stepped-pyramidal weir without sill, the falling jet from the steps have gradually decreased in thickness and it falls discontinuously in steps 5 and 6. By installing the sill at the end of each step, although turbulence and mixing of air and water occurred by formation of hydraulic jump but due to the reduction in the thickness of the falling jet, the intensity of mixing is low and, the performance of stepped-pyramidal weirs with end sill reduced. For the mentioned flow rate, the time to reach DO to from 2 to 7 mg/l for different stepped-pyramidal weir geometries is 857 seconds on average which injected 2. 3 mg. l/s dissolved oxygen into the water content of recipient tank. By increasing the flow rate to h/yc equal to 5. 6 (flow discharge of 3 l/s) for the first step, the thickness of the falling jet and corresponding flow velocity increases and the overall performance of the stepped-pyramidal weir to increasing dissolved oxygen improved. For mentioned flow discharge, the time of increase of DO to reach its initial level is 735 seconds on average, which dissolved oxygen injected by rate of 2. 5 mg. l/s into the water content of the recipient tank. by further increase of flow discharge to 6 l/s (h/yc equal to 6) turbulence and mixing of air and water intensified by formation of hydraulic jump. Also, in the mentioned flow and relative critical depth, more turbulence was observed at the end of each steps along with the sill or labyrinth sill. The results show that, with the exception of the SG3 geometry (stepped-pyramidal weir with sill and labyrinth with the space of 4h), the other structures had similar performance. The results showed that the time duration of DO concentration from 2 to 7 mg/l is 395 seconds on average, the lowest value of which was related to SG2 geometry (stepped-pyramidal weir with sill) which could inject dissolved oxygen on an average of 2. 3 mg. l/s into water content of the recipient tank. At the maximum h/yc equal to 3. 2 (flow rate of 7 l/s) for the first step, the mixing of air bubbles and turbulence of flow on each step causes the labyrinth sill with small length could better performance due to more separation of falling jet of over passing. The time duration to reach the DO concentration from 2 to 7 mg/l is 294 seconds on average. The SG5 geometry (stepped-pyramidal weir with labyrinth having internal space of h) had the best performance. In general, dissolved oxygen is injected into water content of the recipient tank at an average of 2. 7 mg. l/s.  ConclusionThe results showed that at the low thickness of overpassing flow with h/yc> 10, simple stepped-pyramidal weir had better performance than other geometries and could inject 2. 9 mg. l/s of dissolved oxygen into the water. The comparison of the results indicates that as the flow rate increases, due to the increase of turbulence and mixing of air bubbles into overpassing flow at each step, the performance of the steps with a simple and labyrinth sill improves, so that their performance to inject dissolved oxygen is from 2 to 3. 3 mg. l/s. In general, among the different geometries of the stepped-pyramidal weir, the SG2 geometry had the best performance. Experiments have been carried out on a stepped-pyramidal weir model in the Hydraulic Modeling Laboratory at of University of Guilan. The physical model of the stepped-pyramid weir is made of PVC panels with a constant slope of 1: 2 and the number of steps is 6, with dimensions of 4 cm high and 8 cm long. The weir was installed on Iron’s tank with dimensions of 1. 5 m length and 1. 5 m in width and 1 m height. A centrifugal pump device with maximum flow rate of 8 l/s was used to provide desired flow discharge. In order to measure the flow rate, an ultrasonic flow meter was used with an accuracy of ±0. 01 l/s. In each geometry of the weir and desired flow rate, first the concentration of dissolved oxygen in the water supply tank was reduced to 2 mg/l using Na2SO3 solution, then variation of dissolved oxygen concentration was measured by 2 oxygen meters (DOmeter) model AL20Oxi manufactured by Aqualytic company, which was installed on both sides of the tank, until the dissolved oxygen concentration reached on its initial level. In this research, totally 30 tests were carried out to consider effect of the stepped-pyramidal weir on increasing the dissolved oxygen concentration. Results and discussionThe performance of stepped-pyramidal weirs with different geometries at h/yc equal to 7. 4 (flow discharge of 2 l/s) for the first step indicates that for stepped-pyramidal weir without sill, the falling jet from the steps have gradually decreased in thickness and it falls discontinuously in steps 5 and 6. By installing the sill at the end of each step, although turbulence and mixing of air and water occurred by formation of hydraulic jump but ue to the reduction in the thickness of the falling jet, the intensity of mixing is low and, the performance of stepped-pyramidal weirs with end sill reduced. For the mentioned flow rate, the time to reach DO to from 2 to 7 mg/l for different stepped-pyramidal weir geometries is 857 seconds on average which injected 2. 3 mg. l/s dissolved oxygen into the water content of recipient tank. By increasing the flow rate to h/yc equal to 5. 6 (flow discharge of 3 l/s) for the first step, the thickness of the falling jet and corresponding flow velocity increases and the overall performance of the stepped-pyramidal weir to increasing dissolved oxygen improved. For mentioned flow discharge, the time of increase of DO to reach its initial level is 735 seconds on average, which dissolved oxygen injected by rate of 2. 5 mg. l/s into the water content of the recipient tank. by further increase of flow discharge to 6 l/s (h/yc equal to 6) turbulence and mixing of air and water intensified by formation of hydraulic jump. Also, in the mentioned flow and relative critical depth, more turbulence was observed at the end of each steps along with the sill or labyrinth sill. The results show that, with the exception of the SG3 geometry (stepped-pyramidal weir with sill and labyrinth with the space of 4h), the other structures had similar performance. The results showed that the time duration of DO concentration from 2 to 7 mg/l is 395 seconds on average, the lowest value of which was related to SG2 geometry (stepped-pyramidal weir with sill) which could inject dissolved oxygen on an average of 2. 3 mg. l/s into water content of the recipient tank. At the maximum h/yc equal to 3. 2 (flow rate of 7 l/s) for the first step, the mixing of air bubbles and turbulence of flow on each step causes the labyrinth sill with small length could better performance due to more separation of falling jet of over passing. The time duration to reach the DO concentration from 2 to 7 mg/l is 294 seconds on average. The SG5 geometry (stepped-pyramidal weir with labyrinth having internal space of h) had the best performance. In general, dissolved oxygen is injected into water content of the recipient tank at an average of 2. 7 mg. l/s. Conclusion The results showed that at the low thickness of overpassing flow with h/yc> 10, simple stepped-pyramidal weir had better performance than other geometries and could inject 2. 9 mg. l/s of dissolved oxygen into the water. The comparison of the results indicates that as the flow rate increases, due to the increase of turbulence and mixing of air bubbles into overpassing flow at each step, the performance of the steps with a simple and labyrinth sill improves, so that their performance to inject dissolved oxygen is from 2 to 3. 3 mg. l/s. In general, among the different geometries of the stepped-pyramidal weir, the SG2 geometry had the best performance.