Width Of Transition Zone Research Articles

Observations of Crack Initiation and Stable Growth Processes in Fracture Toughness Testing of Several Steels

The processes of initiation and stable growth of craks in fracture toughness tests were observed in detail on various steels of moderate ductility by using fractographic and sectioning techniques. The effects of test temperature and specimen thickness on these processes were also investigated. The results are summarized as follows.(1) The stretched zone width increases with temperature for HT80, HT60 and CH1 steels, while it remains approximately constant for S35C steel, in the temperature range where the stable crack growth takes place preceding the unstable crack growth.(2) The distribution of the stretched zone width along the crack front is fairly flat and is little affected by the test temperature and specimen thickness, while that of the tear dimple region is considerably affected by these factors.(3) A good correlation is found to exist between the transition zone width and Kc/σY.

Strength of VK15-hard-alloy/U8-steel joints produced by welding with Fe-Ni shims containing various amounts of Pd

1. A study was made of the effect of palladium on the processes of diffusional interaction in the system WC-Co/Fe-Ni/U8. It was established that palladium activates the diffusion processes in this system, resulting in the formation of a wider transition zone. 2. A study was made of the effect of palladium concentration in sintered iron-nickel shims on the strength of VK15-hard-alloy/US-carbon-steel joints produced by diffusion welding. It was established that the optimum palladium content of iron-nickel shims is 4 wt.%.

Two-dimensionality of magnetic anomalies over Iceland and Reykjanes Ridge

The relationship between the magnetic anomalies over Iceland and those over Reykjanes Ridge is investigated using the data of the 1965 Dominion Observatory survey. A method is developed for determining the two-dimensionality of the anomalies from the component data measured in this survey. This method is based on testing the first and the second derivative of the magnetic potential with respect to the direction of two-dimensionality, using the component data along a single flight line. Testing the first derivative also yields the direction of two-dimensionality. The outcomes of the two tests (based on a single line) are compared with the observed two-dimensionality (established by narrowly spaced earlier surveys) of Reykjanes Ridge, showing good agreement. As the outcomes of the two tests provide complementary information they are combined into a single factor: A. This factor of two-dimensionality is very low for the anomalies over the shelf of Iceland indicating that the anomalies over Iceland cannot be continued directly into those over Reykjanes Ridge. Over Iceland A is generally low. Over the neovolcanic zone in eastern Iceland twodimensionality is associated with long wavelengths that are not present in the spectrum of the anomalies over Reykjanes Ridge. Thus, Reykjanes Ridge-type anomalies are absent with the exception of the central anomaly. This may not be used as evidence against crustal spreading since the kinematic model proposed by Palmason for Iceland has a wide transition zone between rock of opposite polarity. The same model if computed for a mid-ocean ridge has narrow transition zones. The larger width of the transition zone blurs the anomalies related to the reversals of the earth magnetic field.

Rapid detection of neonatal hypoglycaemia. Evaluation of Dextrostix Reflectance Meter system.

<h3>Introduction</h3> Oesophageal high resolution manometry (OHRM) is a fast developing area of medicine. Whilst seemingly being at the “cutting edge” of technological advancement, it is a relatively simple procedure to perform and interpret. Its ability to demonstrate functional as well as anatomical abnormalities, has led to a range of new diagnoses and shed light on areas of previous clinical and management dilemma. Despite this, few hospitals outside of the large central teaching hospitals, have embraced this new technology. <h3>Objective</h3> To assess the demand for OHRM within a district general hospital (DGH). To assess the reasons for referral and the general outcomes from the procedure. <h3>Methods</h3> The Luton &amp; Dunstable Hospital set up a new OHRM service in July 2009. Prospective procedure related information was stored on a HRM database. This database was analysed to assess total number of procedures performed, the reasons for referral and the diagnostic outcome of those procedures. <h3>Results</h3> Over the course of the first 2 years, a total of 162 procedures were performed. Patients were referred in with a range of symptoms, often in combinations. Of these 162 patient 9 suffered dental problems, 31 had globus, 32 had persistent sore throat, 27 had chronic cough, 13 had nocturnal cough, 118 had endoscopic negative reflux-like symptoms, 40 had endoscopy negative dysphagia, 30 had atypical chest pains, 1 had persistent nausea, 24 had dysphonia and 2 were for reflux assessment. A wide range of diagnoses were made often in combination, including; - 52 with reduced LOS pressures, 18 with a small LOS, 58 with a hiatus hernia, 52 with acid reflux, 40 with non-acid reflux, 75 with oesophageal dysmotility, 23 with oesophageal spasm, 6 with hypertonic contractions, 19 with hypotonic dysmotility, 5 with achalasia type 2, 4 with achalasia type 3, 15 with a wide transition zone, 17 with transient LOS relaxation, 3 with poor pharyngeal co-ordination, 1 with food bolus, and 20 who were normal. <h3>Conclusion</h3> OHRM is relatively simple procedure to perform and interpret. With its ability to diagnose both functional and anatomic abnormalities it has become an invaluable part of our DGH gastroenterology unit. Given the clear benefits over standard manometry, we believe that all patients throughout UK should have access to an OHRM service. <h3>Disclosure of Interest</h3> None Declared.

Oil-Water Transition Zone in a Permeability Trap, with Reference to Free Water Surface

This paper deals mainly with the distribution of oil and water in a reservoir with gradual change in rock charateristics, from a viewpoint of reservoir geology. In this paper, water-wet sandy reservoirs under hydrostatic condition are considered. (Reservoirs under hydrodynamic condition will be discussed in the near future.)Before taking up the main subject, it is necessary to make the concept of free water surface clear. In a sand reservoir of uniform rock characteristics, a cave of supercapillary size is assumed. An oil-water interface in the cave is the free water surface (Fig. 1A). If oil and water have a phase continuity in the reservoir respectively, and if the displacement pressure of the reservoir sand is not zero, relationships between water saturation and height, and between fluid pressures and height, are shown in Fig. 1B and 1C respectively. However, the shape of capillary pressure curve changes with the change of reservoir rock characteristics, as shown in Fig. 2. Fig. 3 shows a generalized relationship between relative permeability curves and the oil-water transition zone. This figure is drawn taking into consideration the free water surface and displacement pressure.In case where there is a lateral and gradual change in reservoir rock characteristics, Fig. 4 was proposed by J. J. Arps (1964). I have revised this figure taking displacement pressure into consideration (Fig. 5). In any event, as a thick reservoir rock changes laterally and gradually from well-sorted coarse-grained clean sand to poorly-sorted fine-grained shaly sandstone, oilwater transition zone will certainly get thicker and be shifted upwards above the free water surface.Based upon these considerations I discuss the distributions of oil and water in a permeability trap. Fig. 6 shows a gently dipping reservoir, in which well-sorted coase-grained clean sand changes gradually into mudstone in the updip direction, via poorly-sorted fine-grained shaly sandstone. When oil is trapped in this reservoir, a sharp oil-water contact is formed on the downdip side. Above this contact oil reservoir with a small amount of interstitial water exists. Further up the dip, water saturation is considered to be getting larger, forming a wide oil-water transition zone. Provided that the first exploratory well (Well 1) was encountered with the transition zone, the second well (Well 2) will be drilled on the updip side, so long as the geometry of the sandstone body and its lithologic characteristics are unknown. But, Well 2 will be a dry hole. Well 3, located on the downdip side, will produce oil.I think such a type of oil pool as shown in Fig. 6 is likely to be often overlooked, and many such pools may be awaiting discovery. How to find out this type of pools by the minimum number of wells is an important practical problem. Sedimentological analysis of cores, high density analysis of continuous dipmeter logs, shape analysis of S.P, curves, etc. in connection with the sedimentological and geohistorical studies on the surrounding area seem to be most effective.

Effect of Aquifer Turbulence on Well Drawdown

The change from laminar flow to turbulent flow, in the case of water flowing through sand, occurs over a wide transition zone beginning with a Reynolds number of about 10. A method for estimating the exponent of the velocity term for head loss calculations involving flow into wells is presented. Typical calculations show that head losses due to aquifer turbulence may have been over-estimated in previously published material.