181 research outputs found
Ovarian Splenosis: A Case Report
Splenosis is auto transplantation of splenic tissue following traumatic rupture of the spleen. In females it can mimic endometriosis when symptomatic. Asymptomatic splenosis is common than previously suspected and it can also involve ovary. In a patient with a history of splenectomy, splenosis can act and provide the function of the spleen and thus should not be routinely excised.
We report a case of an asymptomatic, incidental ovarian splenosis of left ovary accompanying multiple pelvic and serosal splenotic nodules. To our best knowledge, total three cases of ovarian splenosis have been reported previously including two cases of ovarian splenosis accompanying pelvic and serosal splenotic nodules and one case of solitary ovarian splenosis
Will cool roofs improve the thermal performance of our built environment? A study assessing roof systems in Bahrain
A number of international campaigns have recently proposed the use of cool roofs worldwide in order to cope with the summer urban heat island (UHI) effect. This work investigates cool roof strategy and examines the potential of such a strategy for Bahrain. Full-scale measurement, meteorological modelling and thermal simulation of five standard roofs were performed during particular summer days due to the high intensity levels of solar irradiation. This work shows that the light tile roof and metal decking are relatively cooler and more comfortable than others and that the maximum reduction in heat gain occurs for a light tile roof with thermal insulation materials. Nevertheless, without insulation the cooling load is increased by only 1.3%. This percentage seems not to be cost-effective where economics and building construction are concerned. In contrast, the reduction percentage due to the use of thermal insulation in the case of dark tile roof, felt bitumen roof and screed roof increases to 5–7%, which is more cost effective. This work concludes that the cool roof strategy is the most cost-effective for the hot climate of Bahrain, which has a long cooling season. With the current levels of urban development in Bahrain, cool roofs can reduce UHI intensity and building cooling loads, lowering demand for electricity and greenhouse gas emissions from power plants. To avoid any negative consequences from using this strategy, however, trade-offs between urban mitigation and adoptation strategies and complementary technologies should be accounted for in future urban development plans
Technical and Energy Assessment of Building Integrated Photovoltaic Systems applied to the UAE Office Buildings
In the market, the embodied energy payback time (EPBT) is the scale to measure and compare the viability of PV systems against other technologies. Although the impact of PV panels on the operational energy is significant, it is not considered at the time of EPBT estimation. Including savings in operational energy gained over the PV system life leads to shortening the total EPBT. This study shows that the ratio between PV outputs and savings in energy due to PV panels is about 1:3. For the southern and western PV facades of the UAE office buildings, the embodied energy payback time is 12-13 years. When reductions in operational energy are considered the payback time can be reduced to 3 years. It is obvious that the reduction in the operational energy due to the PV panels represents an important factor when the EPBT is estimated
Fixed point theorem in fuzzy metric space for owc maps satisfying integral type inequality
This paper introduces the fixed point in complete fuzzy metric space, and how to find a common fixed point between occasionally weakly compatible mappings
Sustainable Potentials of Plastics Waste-cement Kiln Dust Blends on Strength Properties of Subbase Soil
There are large deposits of waste materials from various industrial or building activity all over the world. Out of this enormous quantity of waste, a little amount gets recycled, while the rest is dumped in vulnerable places. This paper examines the potential use of waste materials in subbase, including recycled chips derived from waste polyethylene terephthalate plastics and cement kiln dust resulting from Portland cement industry as by-product. Samples were formed by blending fractions of 0, 4, 6, and 8% recycled chips with or without 3% cement kiln dust (CKD) by the required weight of subbase soil. The influence in terms of strength was evaluated using CBR values, which exhibited descending values with increasing recycled plastics chips contents. While the addition CKD significantly enlarged the values. Based on the CBR values 4% recycled plastics chips with 3% CKD blend is commended for subbase layer in roads construction
A Statistical Model to Assess Indirect CO2 Emissions of the UAE Residential Sector
This study presents a regional bottom-up model for assessing space cooling energy and related greenhouse gas emissions. The model was developed with the aim of improving the quality and quantity of cooling energy and emission data, especially for the benefit of local decision making. Based on a benchmarking study, a representative archetype was developed, simulation software used and linear statistical model constructed. This model explores the way in which CO2 emission levels are affected by different energy efficiency measures to reduce cooling energy consumption in buildings. The analysis showed that improving building energy efficiency could generate considerable carbon emissions reduction credits with competitive benefit. The developed model was found to be capable in selecting cost-effective, environmentally-preferred building efficiency measures and evaluating the future trend of CO2 emissions in the residential building of Al-Ain city
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Mutual coupling suppression in multiple microstrip antennas for wireless applications
This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonMutual Coupling (MC) is the exchange of energy between multiple antennas when placed on
the same PCB, it being one of the critical parameters and a significant issue to be considered
when designing MIMO antennas. It appears significantly where multiple antennas are placed
very close to each other, with a high coupling affecting the performance of the array, in terms
radiation patterns, the reflection coefficient, and influencing the input impedance. Moreover;
it degrades the designed efficiency and gain since part of the power that could have been
radiated becomes absorbed by other adjacent antennas’ elements. The coupling mechanism
between multiple antenna elements is identified as being mainly through three different paths
or channels: surface wave propagation, space (direct) radiation and reactive near-field
coupling.
In this thesis, various coupling reduction approaches that are commonly employed in the
literature are categorised based on these mechanisms. Furthermore, a new comparative study
involving four different array types (PIFA, patch, monopole, and slot), is explained in detail.
This thesis primarily focuses on three interconnected research topics for mutual coupling
reduction based on new isolation approaches for different wireless applications (i.e. Narrowband,
Ultra-wide-band and Multi-band).
First, a new Fractal based Electromagnetic Band Gap (FEBG) decoupling structure between
PIFAs is proposed and investigated for a narrowband application. Excellent isolation of more
than 27 dB (Z-X plane) and 40 dB (Z-Y plane) is obtained without much degradation of the
radiation characteristics. It is found that the fractal structures can provide a band-stop effect,
because of their self-similarity features for a particular frequency band.
Second, new UWB-MIMO antennas are presented with high isolation characteristics.
Wideband isolation (≥ 31 dB) is achieved through the entire UWB band (3.1-10.6 GHz) by
etching a novel compact planar decoupling structure inserted between these multiple UWB
antennas.
Finally, new planar MIMO antennas are presented for multi-band (quad bands) applications.
A significant isolation improvement over the reference (≥ 17 dB) is achieved in each band by
etching a hybrid solution.
All the designs reported in this thesis have been fabricated and measured, with the simulated
and measured results agreeing well in most cases
Investigation the Coating of Hydroxyapatite on Titanium Substrate by Pulse Laser Deposition
بحثت هذه الدراسة وأعدت طلاء مركب للمزروعات الجراحية باستخدام المواد السيراميكيه النشطه بايولوجيا (bioactive) مثل الهيدروكسيابتايت كطلاءات للمزروعات المعدنيه التي تشجع النمو الطبيعي للعظام عند نقاط التماس بينها وبين العظم الحي. ان الهيدروكسيابتايت (Ca10(PO4)6(OH)2)) او فوسفات الكالسيوم يستخدم كطلاء للمعادن بسبب توافقيته الحياتيه الممتازه كما انه ذو هيكل مشابه للانسجه الصلبه في جسم الانسان. إن تطبيق الطلاء HA على ركائز التيتانيوم أنتجت باستخدام تقنية الترسيب بالليزر النبضي (Pulsed Laser Deposition). في هذا البحث استخدم (HA) كهدف ((Target تم كبسه عند ضغط (150MPa) مع حجم حبيبي مقداره 2.745 µm)) واستخدامه في عملية الطلاء بواسطة تقنية(PLD). أجريت عدة اختبارات لتوصيف طبقة الطلاء مثل XRD وSEM وAFM وEDX لتحديد كمية كلا من الكالسيوم (Ca) والفسفور (P) في طبقة الطلاء. وبعدها تم اختبار الصلاده وخشونة السطح لطبقه الطلاء HA)). تم اجراء اختبار التآكل باستخدام طريقة استكمال منحني تافل في محلول Hank's solution لكل النماذج المطليه وغير المطليه، حيث حصلنا في هذا الاختبار على تحسن كبير في مقاومة التآكل للعينات المطليه عند عدد نبضات 4000 نبضة بمقدار 99.88%.This study investigated and prepared a coating for surgical implants by using hydroxyapatite (HA) empowers characteristic bone that developed at a medium for prosthetic the parts of human body. HA is the generally manufactured from both Calcium (Ca) and Phosphate (P) to produce (Ca10(PO4)6(OH)2) that used as a base material for covering mineral embeds because of its incredible biocompatibility and comparable the synthesis and structure to sclerous tissues of the human body. HA, coatings on titanium substrates have been produced by Pulses laser deposition (PLD) techniques. HA used in this search pressed at pressure (150MPa) with particle size (2.745 µm) and used as a target in coating by (PLD) techniques. Surface characterization studies of the coatings such as XRD, SEM, AFM and EDX to detect the amount of (Ca) and (P) in coating layer were carried out. Then test the micro-hardness, surface roughness for HA coating .Corrosion behavior for uncoated and coated samples with various number of pulses in Hank’s solution by using OCP and the potentially static polarization test were achieved also, , in this test we obtained a greatly improved in corrosion resistance of the samples B1 after coating by 99.88%
Hematopoietic Stem Cell Function in a Murine Model of Sickle Cell Disease
Previous studies have shown that the sickle environment is highly enriched for reactive oxygen species (ROS). We examined the oxidative effects of sickle cell disease on hematopoietic stem cell function in a sickle mouse model. In vitro colony-forming assays showed a significant decrease in progenitor colony formation derived from sickle compared to control bone marrow (BM). Sickle BM possessed a significant decrease in the KSL (c-kit+, Sca-1+, Lineage−) progenitor population, and cell cycle analysis showed that there were fewer KSL cells in the G0 phase of the cell cycle compared to controls. We found a significant increase in both lipid peroxidation and ROS in sickle-derived KSL cells. In vivo analysis demonstrated that normal bone marrow cells engraft with increased frequency into sickle mice compared to control mice. Hematopoietic progenitor cells derived from sickle mice, however, demonstrated significant impairment in engraftment potential. We observed partial restoration of engraftment by n-acetyl cysteine (NAC) treatment of KSL cells prior to transplantation. Increased intracellular ROS and lipid peroxidation combined with improvement in engraftment following NAC treatment suggests that an altered redox environment in sickle mice affects hematopoietic progenitor and stem cell function
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