Academic literature on the topic 'Tile Holes (TH)'

Radioactive waste is generally classified as low and intermediate level waste (LILW) and high-level waste (HLW), based on their level of radioactivity and the time taken for decay. The low and intermediate level solid/solidified wastes are emplaced in near surface shallow land repository and are termed as Near Surface Disposal Facility (NSDF). A near surface disposal facility (NSDF) is proposed to be built at Kalpakkam, Tamil Nadu. Kalpakkam is situated about 70 km south of Chennai (12o33’ N Lat and 80o11’ E Long) along the east coast of India. Several of India’s nuclear installations like Madras Atomic Power Station, Fast Breeder Test Reactor, Kalpakkam Reprocessing Plant and Indira Gandhi Centre for Atomic Research (IGCAR) are located in Kalpakkam. Typical reinforced concrete trench (RCT) for disposal of low and intermediate level nuclear waste have major portion of RCT being located below the ground surface and above the water table, i.e., in the vadose zone. Available studies on the mineralogical and physico-chemical characterization of clays at Kalpakkam nuclear plant site have not focused on the mineralogical, physico-chemical and hydraulic properties of soils in vadose zone. The physico-chemical properties of soils are important as they strongly affect the fate and mobility of radioactive contaminants in the sub-surface soil. The hydraulic properties of soils in the vadose zone differ from those in the saturated zone owing to dis-continuity in water filled voids that makes the flow path more tortuous; additionally presence of suction in soil voids renders gradient causing flow to vary with the soil moisture content. Strontium is the selected contaminant solute in this thesis as the waste inventory of proposed NSDF at Kalpakkam shall predominantly contain radioactive strontium and cesium ions. The unsaturated (vadose) zone housing the buried portion of RCT is important as hydraulic characteristics (void ratio, degree of saturation, volumetric water content, suction and unsaturated permeability coefficient) influence the transport of moisture and thereby of the solute dissolved in the moisture to underlying groundwater table, upon breach of the RCT. The physico-chemical properties (pore water chemistry, cation exchange capacity of soils) of the vadose zone soil play significant role in solute transport by way of adsorption/ion-exchange and desorption of the contaminant. Given the significance of hydraulic and physico-chemical properties of the vadose zone soil in influencing solute transport and the lack of studies in this direction in the Indian context, the present thesis examined strontium adsorption and transport for soils obtained from the vadose zone region of proposed NSDF at Kalpakkam, Tamil Nadu, India from 2 pits (termed Pit 1 and Pit 2). Strontium adsorption studies by the NSDF soils were accomplished from batch and miscible displacement column experiments.

The Union attack on May 19 was not well planned, and it was based on poor intelligence of the Confederate defences and the opposing troops. But Grant wanted to make the effort, banking on the emotional impact of his overland campaign on Confederate morale. It was a logical hope and if successful would have delivered Vicksburg into Federal hands without the time and investment of resources and loss of life incurred by a lengthy siege of the city. But his hopes for a general attack fell through. The only serious attack that went in as scheduled at 2 p.m. was that conducted by Frank P. Blair’s division of William T. Sherman’s Fifteenth Corps, on the Union right. Blair attacked the strongest segment of the Confederate line of earthworks, the areas around Stockade Redan and the 27^th Louisiana Lunette at the northeastern corner of Lockett’s line. Blair’s men were repulsed with substantial losses.

The majority of experiments in neurophysiology are based upon spike trains recorded from individual or multiple nerve cells. If all the action potentials are taken to be identical and only the times at which they are generated are considered, the experimentalist obtains a discrete series of time events {t1,···, tn}, where t¡ corresponds to the occurrence of the i th spike, characterizing the spike train. This spike train is transmitted down the axon to all of the target cells of the neuron, and it is this spike train that contains all of the relevant information that the cell is representing (assuming no dendro-dendritic connections). As alluded to in the preceding chapter, there are two opposing views of neuronal coding, with many interim shades. One view holds that it is the firing rate, averaged over a suitable temporal window (Eqs. 14.1 or 14.2), that is relevant for information processing. The dissenting view, correlation coding, argues that the interactions among spikes, at the single cell as well as between multiple cells, encodes information. A key property of spike trains is their seemingly stochastic or random nature, quite in contrast to switching in digital computers. This randomness is apparent in the highly irregular discharge pattern of a central neuron to a sensory stimulus whose details are rarely reproducible from one trial to the next. The apparent lack of reproducible spike patterns has been one of the principal arguments in favor of the hypothesis that neurons only care about the firing frequency averaged over very long time windows. Such a mean rate code is very robust to “sloppy” hardware but is also relatively inefficient in terms of transmitting the maximal amount of information per spike. Encoding information in the intervals between spikes is obviously much more efficient, in particular if correlated across multiple neurons. Such a scheme does place a premium on postsynaptic neurons that can somehow decode this information. Because little or no information can be encoded into a stream of regularly spaced action potentials, this raises the question of how variable neuronal firing really is.

Abstract With the objective to drill two wells shared from one conductor with independent wellhead and completion, ADNOC Offshore drilling team pioneered for the first time in Umm Lulu field and ADNOC UAE the Conductor sharing drilling technique. Which is to drill two wells from one single conductor in wellhead tower. Well planning technique drilling 42" hole and run 36" conductor, then install lower male connector and run conductor Down Hole Guide (DHG) assembly to be a guide for both two wells. Land the DHG on the lower male connector. Install upper male connector, which is equipped with two well slots for drilling the two wells. Drilling 1st 16" hole and run 13 3/8" casing and cemented. Skid over second slot and drill second hole 16" and run and cement 13 3/8" casing and carry out top up cement job for both hole up to surface inside 36" conductor. Install casing head housing for each well. Then each well could be drilled as per normal procedures. Well executing process. Well challenges: Drilling large hole 42" hole with 42" bit and BHA. Run 36" conductor and conductor sharing DHG and keep aligned for accessibility of BHA and casing Nudge 16" hole for both two wells at centre-to-centre distance 8" safely without collision issue. Run two 13 3/8" casing strings in 36" conductor and cement same up to surface. Complete drilling well UL-056 from slot A, drilled 12 ¼" hole section to TH-I ABS, run 9 5/8" casing and perform cement job to surface, drilled 6" hole (linerless design) and land in TH II then continued drilling horizontal drain to TD, Run completion and deliver the well. Suspend the other well in slot B at 13 3/8" casing with securing the well with abandonment cap and as per ADNOC offshore policy.

Abstract The increased demand for smaller and more reliable electronic devices, pressures companies to tune and innovate the production methodologies, always aiming to decrease the production time while maintaining the products’ quality. In the manufacturing of a Printed Circuit Board - PCB, there are two main types of electronic components, namely, Surface-Mount-Devices and Through-Hole components. Both connections are achieved through soldering, an essential manufacturing process that greatly affects the quality of the final product, and may compromise the lifetime of the PCB. While SMD components are commonly soldered by a reflow process, TH components are generally soldered by a wave soldering process. However, a PCB is generally composed of both types of components. Since both processes are too different in nature, the manufacturing of the board requires two separated mounting lines which represent increased costs and production time. Taking this into account, the present study investigates the usage of the reflow solder printing to deposit the solder paste on through-hole apertures both experimentally and numerically. In general, the results were similar showing a tendency for the solder paste to deposit on the aperture’s right side. Nevertheless, the numerical model predicts a filling area greater (by 22%) than that verified experimentally.

Sefton, on the north side of Liverpool, holds a radioactive legacy from its industrial past. This legacy is in the form of Tin slag buried in sub-surface seams. Located near the docks and adjacent to the rich Lancashire coal seams, Sefton became one of the main production centres of Tin plate in Britain. A consequence of this industrial process is the production of mildly radioactive waste slag. Tin rich ores are heated under reducing conditions to produce a molten metal stream This is then separated into the component metal streams. Solid wastes produced by this process are known as slag and were usually stored on site in spoil heaps. Because this slag is a very hard, glassy material it has been historically used as aggregate in underlying roads and rail way sleepers. Many of these sites pre-date the introduction of the regulation of radioactive substances in the UK and have never been under legislative control under the Radioactive Substances Act, RSA93. There is a risk that the existence may not be known of some of these sites. U-238 and Th-232 and their associated decay chains, are the major contributors to the radionuclide inventory of the slags, levels of these radionuclides being in the range 1–10Bq/g. A series of alpha and beta decays for both chains leads eventually to the generation of a stable isotope of lead. Radiologically, the main area of concern is with the potential inhalation or ingestion of contaminated dusts. There is also a potential for Ra-226 to leach out into groundwater. AMEC has worked for Sefton Metropolitan Council and various developers, to carry out specialist, non intrusive gamma radiation surveys of numerous sites in Sefton. This is the first stage in carrying out a radiological risk review of a given site. What often then follows is an intrusive, geo-technical survey, with trial pitting and radiological sampling for later sensitive lab based radiochemical analysis. Radiological supervision is also required at this time to ensure that the radiological exposure of the Contractors carrying the survey is restricted and ensure that plant dose not become contaminated with radionuclides. These surveys are the preliminary stage for redevelopment works with new housing replacing antiquated commercial premises. By bringing together expertise in sensitive gamma surveying, radiochemical analysis and a detailed understanding of the regulatory framework, AMEC is able to support the borough of Sefton in its re-development programme ensuring safe compliant development of an area with an historic radiological legacy.