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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
251

The Chronostratigraphy of Big Bone Lick and its Archaeological Implications

Mortensen, Litsa A. 18 October 2013 (has links)
No description available.
252

Effects of Faceseal Leakage, Combustion Material, Particle Size, Breathing Frequency and Flow Rate on the Performance of Respiratory Protection Devices

He, Xinjian 25 October 2013 (has links)
No description available.
253

Determination of the Optimal Starter Particle Size for Improved Starter and Overall Broiler Performance

Lemons, Mark Edward 10 August 2018 (has links)
It is appreciated that improvements in feed form (FF) result in improved broiler performance. However, research has primarily focused on the finishing growth phase due to associated high feed consumption allowing the greatest opportunity to observe performance benefits. Due to lower feed volumes required in the starter growth phase, it may be more economical to improve FF in the starter phase if improvements in overall performance and processing characteristics are observed. Study 1 investigated the potential for interactive effects of high or low FF presented in each of three growth phases to influence broiler performance. These data demonstrated the potential for FF presented in the starter phase to interact with FF in the finisher phase influencing day (d) 46 ending body weight (BW). Due to starter FF impacting overall performance, this led to Study 2 which consisted of two experiments with the main objective of determining the optimal crumble particle size for improved starter (d 0-14) performance. Experiment 1 utilized 5 different crumble particle sizes ranging from 1202- 2172 µm; whereas Experiment 2 implemented 8 differing crumble particle sizes ranging from 1174- 3736 µm. These data demonstrated consistent improvements in feed conversion ratio (FCR) as crumble particle size increased, with improvements in BW gain being demonstrated in Experiment 2 for crumbles 2800 µm and larger. Due to associated performance benefits with large particle sizes, Study 3 examined the potential to feed pellets, in comparison to crumbles, at different qualities during the starter period. Additionally, two commonly used genetic strains were employed to determine if performance benefits due to FF and feed quality (FQ) would be similar among different strains. Lastly, common diets were fed following the starter phase to determine if benefits due to starter FF would translate to improved overall performance. Feed quality and FF interacted to influence d 18 BW and d 0-18 BW gain. Examining carryover effects, d 0-32 and 0-46 FCR were influenced by FF and FQ; whereas d 0-62 was not influenced. These data suggest that length of the growout should be considered for determining FQ and FF to present in the starter growth phase.
254

Fluxes, dynamics and chemistry of particulates in the ocean

Gardner, Wilford Dana January 1978 (has links)
Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Earth and Planetary Sciences. / Microfiche copy available in Archives and Science. / Vita. / Includes bibliographies. / by Wilford D. Gardner. / Ph.D.
255

Diffusion of light by colloidal clay suspensions

Davis, James Edward January 1933 (has links)
The purpose of this work is to find a method of determining the average particle size in samples of clays and ceramical materials, and to attempt to classify their physical properties according to the size of the particles. Such data should be useful to compare the properties of clays, to match different samples for uniformity, and to better control processes where clays are used, as for instance in manufacture of paper, rubber, and burned wear. / M.S.
256

Roles of limestone particle size ratios and phytase levels on performance, eggshell quality, and bone health in post-peak and late-lay single-cycled W-36 laying hens

Waters, Charis 12 May 2023 (has links) (PDF)
The objective of this study was to investigate the role of fine (F) and coarse (C) limestone ratios and exogenous phytase at standard and superdosing activity on performance, egg quality, and bone quality of post-peak and late-lay Hy-Line W-36 hens. For post-peak, treatments with 40F:60C at 0 and 400 FTU/kg (standard phytase activity) increased hen-day egg production (HDEP). Treatments with 15F:85C decreased feed intake (FI) but also increased unsaleable eggs (UE) and eggshell-breaking strength (EBS). Treatments with 0 and 400 FTU/kg increased albumen quality and treatments with 1500 FTU/kg increased bone quality and phytate breakdown. For late-lay, interaction effects of limestone and phytase were observed for FI, HDEP, UE, bone, and egg quality. Treatments with 40F:60C decreased UE and increased EBS and bone mineral content of aluminum (Al). Treatments with 0 FTU/kg increased eggshell proximate of phosphorus (P) and gizzard pH, but 400 and 1500 FTU/kg increased phytate breakdown and bone quality.
257

Quantitative Analysis Of Mannitol Polymorphs - X-Ray Powder Diffractometry. Exploring Preferred Orientation Effects.

Grimsey, Ian M., Booth, S.W., Campbell Roberts, Sarra N., Williams, Adrian C. 12 August 2009 (has links)
No / Mannitol is a polymorphic pharmaceutical excipient, which commonly exists in three forms: alpha, beta and delta. Each polymorph has a needle-like morphology, which can give preferred orientation effects when analysed by X-ray powder diffractometry (XRPD) thus providing difficulties for quantitative XRPD assessments. The occurrence of preferred orientation may be demonstrated by sample rotation and the consequent effects on X-ray data can be minimised by reducing the particle size. Using two particle size ranges (<125 and 125¿500 ¿m), binary mixtures of beta and delta mannitol were prepared and the delta component was quantified. Samples were assayed in either a static or rotating sampling accessory. Rotation and reducing the particle size range to <125 ¿m halved the limits of detection and quantitation to 1 and 3.6%, respectively. Numerous potential sources of assay errors were investigated; sample packing and mixing errors contributed the greatest source of variation. However, the rotation of samples for both particle size ranges reduced the majority of assay errors examined. This study shows that coupling sample rotation with a particle size reduction minimises preferred orientation effects on assay accuracy, allowing discrimination of two very similar polymorphs at around the 1% level.
258

Dose emission and aerodynamic characterization of the terbutaline sulphate dose emitted from a Turbuhaler at low inhalation flow

Abdelrahim, M.E.A., Assi, Khaled H., Chrystyn, Henry January 2013 (has links)
No / Previously, dose emission below 30 L min(-1) through DPI has not been routinely determined. However, during routine use some patients do not achieve 30 L min(-1) inhalation flows. Hence, the aim of the present study was to determine dose emission characteristics for low inhalation flows from terbutaline sulphate Turbuhaler. Total emitted dose (TED), fine particle dose (FPD) and mass median aerodynamic diameter (MMAD) of terbutaline sulphate Turbuhaler were determined using inhalation flows of 10-60 L min(-1) and inhaled volume of 4 L. TED and FPD increase significantly with the increase of inhalation flows (p <0.05). Flows had more pronounced effect on FPD than TED, thus, faster inhalation increases respirable amount more than it increases emitted dose. MMAD increases with decrease of inhalation flow until flow of 20L min(-1) then it decreases. In vitro flow dependent dose emission has been demonstrated previously for Turbuhaler for flow rates above 30 L min(-1) but is more pronounced below this flow. Minimal FPD below 30 L min(-1) suggests that during routine use at this flow rate most of emitted dose will impact in mouth. Flow dependent dose emission results suggest that Pharmacopoeias should consider the use variety of inhalation flows rather than one that is equivalent to pressure drop of 4 KPa.
259

Utilization of Recycled Brick Powder as Supplementary Cementitious Materials - A Comprehensive Review

Salli Bideci, Ö., Bideci, A., Ashour, Ashraf 26 July 2024 (has links)
Yes / Over the past two decades, extensive research has been conducted to explore alternative supplementary cementitious materials (SCMs) in order to address the environmental concerns associated with the cement industry. Bricks, which are frequently preferred in the construction sector, generate a lot of waste during the production and demolition of existing buildings, requiring environmentally sustainable recycling practices. Therefore, many studies have been carried out in recent years on the use of brick waste as supplementary cementitious materials (SCMs) in cement mortar and concrete production. This critical review evaluates the impact of waste brick powder (WBP) on the mechanical and durability properties of mortar and concrete when used as a partial replacement for cement. It was observed that the properties of WBP-blended cement mortar or concrete depend on several factors, including WBP particle size, replacement ratio, pozzolanic activity, and mineralogical structure. The findings indicate that WBP with a particle size range of 100 µm to 25 µm, with a maximum cement replacement level of 10–20%, exhibits a positive impact on the compressive strength of both mortars and concretes. However, it is crucial to emphasize that a minimum curing duration of 28 days is imperative to facilitate the development of a pozzolanic reaction. This temporal requirement plays a vital role in realizing the optimal benefits of utilizing waste brick powder as a supplementary cementitious material in mortars and concretes.
260

Cattle feedlot dust – laser diffraction analysis of size distribution and estimation of emissions from unpaved roads and wind erosion

Gonzales, Howell B. January 1900 (has links)
Master of Science / Department of Biological & Agricultural Engineering / Ronaldo G. Maghirang / Large cattle feedlots emit considerable amounts of particulate matter (PM), including TSP (total suspended particulates), PM[subscript]10 (PM with equivalent aerodynamic diameter of 10 μm or less), and PM[subscript]2.5 (PM with equivalent aerodynamic diameter of 2.5 μm or less). Particulate emissions result from pen surface disturbance by cattle hoof action, vehicle traffic on unpaved roads and alleyways, and wind erosion. Research is needed to determine concentrations of various size fractions, size distribution, and emission rates from various sources in feedlots. This research was conducted to measure particle size distribution using laser diffraction method and estimate emissions from unpaved roads and wind erosion. Particle size distribution and concentrations of PM[subscript]10 and PM[subscript]2.5 at a commercial cattle feedlot in Kansas (Feedlot 1) were measured over a 2-yr period. The feedlot had a capacity of 30,000 head and total pen area of 50 ha and was equipped with a sprinkler system for dust control. Collocated low-volume samplers for TSP, PM[subscript]10, and PM[subscript]2.5 were used to measure concentrations of TSP, PM[subscript]10, and PM[subscript]2.5 at the upwind and downwind edges of the feedlot. Dust samples that were collected by TSP samplers were analyzed with a laser diffraction analyzer to determine particle size distribution. Particle size distribution at the downwind edge of the feedlot was also measured with micro-orifice uniform deposit impactor (MOUDI). The laser diffraction method and MOUDI did not differ significantly in mean geometric mean diameter (13.7 vs. 13.0 μm) but differed in mean geometric standard deviation (2.9 vs. 2.3). From laser diffraction and TSP data, PM[subscript]10 and PM[subscript]2.5 concentrations were also calculated and were not significantly different from those measured by low-volume PM[subscript]10 and PM[subscript]2.5 samplers (122 vs. 131 μg/m[superscript]3 for PM[subscript]10; 26 vs. 35 μg/m[superscript]3 for PM[subscript]2.5). Both PM[subscript]10 and PM[subscript]2.5 fractions decreased as pen surface moisture contents increased, while the PM[subscript]2.5/PM[subscript]10 ratio did not change much with pen surface moisture content. Published emission models were used to estimate PM[subscript]10 emissions from unpaved roads and wind erosion at Feedlot 1 and another nearby feedlot (Feedlot 2). Feedlot 2 had a capacity of 30,000 head, total pen surface area of 59 ha, and used water trucks for dust control. Estimated PM[subscript]10 emissions from unpaved roads and wind erosion were less than 20% of total PM[subscript]10 emissions obtained from inverse dispersion modeling. Further research is needed to establish the applicability of published emission estimation models for cattle feedlots.

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