4,530 research outputs found
Characterization of water-soluble inorganic ions and carbonaceous aerosols in the urban atmosphere in Amman, Jordan
No full textThe urban particulate matter (PM) carbonaceous and water-soluble ions were investigated in Amman, Jordan during May 2018–March 2019. The PM2.5 total carbon (TC) annual mean was 7.6 ± 3.6 μg/m3 (organic carbon (OC) 5.9 ± 2.8 μg/m3 and elemental carbon (EC) 1.7 ± 1.1 μg/m3), which was about 16.3% of the PM2.5. The PM10 TC annual mean was 8.4 ± 3.9 μg/m3 (OC 6.5 ± 3.1 μg/m3 and elemental carbon (EC) 1.9 ± 1.1 μg/m3), about 13.3% of the PM10. The PM2.5 total water-soluble ions annual mean was 7.9 ± 1.9 μg/m3 (about 16.9%), and that of the PM10 was 10.1 ± 2.8 μg/m3 (about 16.0%). The minor ions (F−, NO2−, Br−, and PO43−) constituted less than 1% in the PM fractions. The significant fraction was for SO42− (PM2.5 4.7 ± 1.6 μg/m3 (10.0%) and PM10 5.3 ± 1.9 μg/m3 (8.3%)). The NH4+ had higher amounts of PM2.5 (1.3 ± 0.6 μg/m3; 2.7%) than that PM10 (0.9 ± 0.4 μg/m3; 1.4%). During sand and dust storm (SDS) events, TC, Cl−, and NO3− were doubled in PM, SO42− did not increase significantly, and NH4+ slightly decreased. Regression analysis revealed: (1) carbonaceous aerosols come equally from primary and secondary sources, (2) about 50% of the OC came from non-combustion sources, (3) traffic emissions dominate the PM, (4) agricultural sources have a negligible effect, (5) SO42− is completely neutralized by NH4+ in the PM2.5 but there could be additional reactions involved in the PM10, and (6) (NH4)2SO4, was the major species formed by SO42−and NH4+ instead of NH4HSO4. It is recommended to perform long-term sampling and chemical speciation for the urban atmosphere in Jordan
Luminescence dating of soils and sediments from Jerash, Jordan
No full textThe urban site of Jerash, Jordan is recognised as one of the great cities of the classical Middle East and has been the subject of ongoing systematic archaeological investigations since the 1920s. Its significance lies in its location on limestone geology in one of the more fertile areas of the Ajlun Highlands in northern Jordan with a good water supply, a number of springs and its central position in regional trade routes. The hinterland context of the city is yet to be considered and is a significant omission given the importance of water and its management together with the agricultural systems dependent on water in supporting urban development. Landscape chronologies are vital to the establishment of city and hinterland relationships and in this working papers we assess the value and significance of optically stimulated luminescence (OSL) measurement in this endeavour. Our findings so far suggest a measurement cluster range of ca. 480 BC – 250 BC in landscapes underlying the city and a dominant trend of sediments infilling the adjacent Wadi Suf between 640 ± 240 AD and 1400 ± 60 AD reflecting land management changes in a soil environment sensitive to degradation
Mechanisms for accumulation and migration of technetium-99 in saltmarsh sediments
No full textThis thesis describes the development of analytical methods for both the bulk determination of 99Tc, and determination of 99Tc in sequential extracts from sediments. These methods have been used to collect data, which, along with trace and major element data have been used to interpret the mechanisms for 99Tc input, migration and accumulation in saltmarshes. The inventory of 99Tc stored in the Thornflatt Saltmarsh, Esk Estuary has also been determined. The routine determination of 99Tc in bulk samples uses 99mTc as a yield monitor. Samples are ignited stepwise to 550°C and the 99Tc is extracted using 8M nitric acid. Many contaminants are precipitated with Fe(OH)3 and the Tc in the supernant is pre-concentrated and further purified using anion-exchange chromatography. Final separation of Tc from Ru is achieved by extraction of Tc into 5% TnOA in xylene from 2M sulphuric acid. The yield is determined by γ-spectrometric analysis of 99mTc. Determination of 99Tc is made by liquid scintillation counting. Typical recoveries are in the order of 70-95% and the method has a detection limit of 1.7 Bq/kg for a sample size of 10g. Determination of Tc in sequential extracts uses operationally defined procedures to extract: exchangeable Tc, reducible Tc and oxidisable Tc. An initial water wash is used to extract any occluded Tc and a final leach in 8 M nitric acid is used to dissolve any residual Tc. The isolation of 99Tc uses TEVA resin for Extracts 1-4 and the decontamination procedure developed for bulk analysis for Extract 5. 99mTc was used as a yield monitor, and determination of 99Tc is by liquid scintillation counting. Limits of detection were dependent on the amount of 99mTc tracer used but were found to be as low as 2.4 Bq/kg for a sample size of 2g. A study was made of the mechanisms responsible for the accumulation and migration of Tc in estuarine sediments using sediments collected from saltmarshes at Thornflatt, Carlaverock and the Ribble Estuary. 99Tc was present at determinable activities in all the sediment cores taken from these sites. Good correlations between Tc and CaO as well as CO3 concentrations and poor correlation between Tc and radionuclides adsorbed to inorganic detritus infer a direct input of 99Tc to marsh sediments. Determination of 99Tc in biota living on the marsh also showed that this was not a significant pathway for input of Tc to the sediments. Sequential extraction data imply sorption to an organic fraction of the sediment. Stable element and sequential extraction data indicates that Tc is readily oxidised and remobilised before reprecipitation where redox conditions are favourable. Data indicate a reduction potential between those of the MnIV to MnII reaction and the FeIII to FeII reaction is necessary for re-accumulation to occur, as suggested by published thermodynamic data. Data collected from reducing sediments imply that similar mechanisms are responsible for the accumulation of Mn (e.g. reduction by sulphate reducing bacteria) and the accumulation of Tc. The inventory of 99Tc held within the Thornflatt saltmarsh is proportionally less than that of 137Cs or 241Am when compared to discharges from Sellafield. However a higher proportion of 99Tc is transferred from Seliafield and incorporated into saltmarsh sediments than is suggested by previously published standard distribution coefficient data. Saltmarsh sediments are therefore a more important sink of 99Tc than extrapolations made from inventories of other radionuclides would suggest
Service-oriented models for audiovisual content storage
No full textWhat are the important topics to understand if involved with storage services to hold digital audiovisual content? This report takes a look at how content is created and moves into and out of storage; the storage service value networks and architectures found now and expected in the future; what sort of data transfer is expected to and from an audiovisual archive; what transfer protocols to use; and a summary of security and interface issues
T0-Berekening: Status Quo van UNIBEST-TC
No full textDit rapport gaat in op de ontwikkelingen bij het UNIBETS-TC model. Met dit model wordt het cross-shore en longshore sediment transport berekend. Om inzicht te krijgen in de verbeteringen in het model wordt er in dit rapport een T0-berekening (een berekening op tijdstip T=0) gemaakt. Dit maakt het mogelijk de ontwikkelingen te evalueren door het te vergelijken met een dergelijke exercitie op het moment T1. Met de berekening wordt er antwoord gegeven op de vragen of het UNIBEST-TC model één heel jaar de ontwikkeling van het kustprofiel kan doorrekenen en in hoeverre het model de werkelijkheid beschrijft. Geconcludeerd wordt dat het (nieuwe) UNIBEST-TC model het dwarstransport in de goede orde van grootte bepaald, maar dat het model geen rekening houdt met het ontstaan van banken. Verder onderzoek is nodig. Het model houdt verder goed rekening met de interactie tussen langs- en dwarstransport en biedt daarnaast een goede mogelijkheid om het lot van een zandsuppletie te bestuderen
Oxidative Dissolution of Tc(IV) Phases by High Valent Manganese Species: Redox Mediated Mobilization of a Risk Driving Radionuclide
No full textThe environmental mobility of Technetium-99 is inextricably tied to its oxidation state. Under oxidizing conditions Tc-99 predominates as the Tc(VII)O4- anion. This anion has a high solubility and is precluded from sorption on most soil or mineral surfaces, giving it a high environmental mobility. Under reducing conditions, Tc-99 predominates as Tc(IV)O2 or Tc(IV)2S7. Tc(IV) species tend to be insoluble and are therefore immobile. Due to this redox dichotomy, there has been significant interest in developing reductive immobilization strategies for Tc-99, particularly in anoxic environments where Tc(IV) is conventionally assumed to be stable. However, O2 is not the only common environmental oxidant. Many high valent manganese species are environmentally prolific and well known to exist in anoxic and overall reducing environments. These powerful oxidants can create localized oxidizing conditions in otherwise reducing environments. Limited research on the oxidation of Tc(IV) species has left a knowledge gap in the true recalcitrance of such immobilization forms in environmental settings. Our work aims to bridge this knowledge gap by studying the oxidation of Tc(IV) by various, environmentally common, high valent manganese species. Mn(III)-ligand complexes in particular have been overlooked. Up until recently, aqueous Mn(III) was assumed to be absent from the environment due to its disproportionation in aqueous systems without suitable complexing ligands. More recently, Mn(III)-ligand complexes have been shown to be prolific in a variety of natural waters. We have shown that various manganese oxides and Mn(III)-ligand complexes are capable of rapidly oxidizing Tc(IV) to Tc(VII), even in the absence of oxygen, resulting in dissolution of Tc-99 and release to the aqueous phase. This thesis presents novel information on the redox interface chemistry of Tc-99, which is crucial to developing effective remediation methods
Real Banach Jordan triples
No full textA theory of real Jordan triples and real bounded symmetric domains in finite dimensions was developed by Loos. Upmeier has proposed a definition of a real
J
B
∗
J{B^ \ast }
-triple in arbitrary dimensions. These spaces include real
C
∗
{C^ \ast }
-algebras and
J
B
∗
J{B^\ast }
-triples considered as vector spaces over the reals and have the property that their open unit balls are real bounded symmetric domains. This, together with the observation that many of the more recent techniques in Jordan theory rely on functional analysis and algebra rather than holomorphy, suggests that it may be possible to develop a real theory and to explore its relationship with the complex theory. In this paper we employ a Banach algebraic approach to real Banach Jordan triples. Because of our recent observation on commutative
J
B
∗
J{B^\ast }
-triples (see §2), we can now propose a new definition of a real
J
B
∗
J{B^\ast }
-triple, which we call a
J
∗
B
{J^\ast }B
-triple. Our
J
∗
B
{J^\ast }B
-triples include real
C
∗
{C^\ast }
-algebras and complex
J
B
∗
J{B^\ast }
-triples. Our main theorem is a structure theorem of Gelfand-Naimark type for commutative
J
∗
B
{J^\ast }B
-triples.</p
Neuroprotective Potential of Tinospora cordifolia in Attenuating Hippocampal CA3 Neuronal Damage in Pregnant Wistar Rats and their Neonates Exposed to Prenatal Vibration Stress and Maternal Separation
No full textالخلفية: يؤثر الإجهاد قبل الولادة سلبًا على الإدراك والسلوك والسمات النفسية والاجتماعية. يُعرف نبات تينوسبورا كورديفوليا (TC) بخصائصه المضادة للإجهاد والمعززة للإدراك. ومع ذلك، فإن فعاليته في مواجهة الإجهاد الناتج عن انفصال الأم واهتزازها غير موثقة جيدًا. هدفت الدراسة إلى تقييم الآثار العصبية الوقائية لنبات تينوسبورا كورديفوليا على الفئران حديثة الولادة التي تعرضت لإجهاد اهتزاز قبل الولادة، وكذلك الإجهاد الناتج عن انفصال الأم.
الطرق: تعرضت فئران ويستار الحوامل في المجموعة المعرضة للإجهاد لثلاث ساعات يوميًا من الإجهاد الاهتزازي، وذلك خلال الفترة من 7 إلى 16 يومًا من الحمل. أُعطيت مجموعة العلاج 6 ملغم/كغم من مستخلص نبات تينوسبورا كورديفوليا قبل التعرض للإجهاد الاهتزازي. فُصل حديثو الولادة عن أمهاتهم وعولجوا بنبات تينوسبورا كورديفوليا بعد الولادة. في نهاية فترة العلاج، خضعت الفئران لمهمة تعلم مكاني. بعد ذلك، عولجت أدمغة الحيوانات لصبغة جولجي كوكس لدراسة التشجير العصبي CA3.
النتائج والاستنتاجات: أظهرت الأمهات المعالجات بمستخلص الكرياتينين تعلمًا مكانيًا أفضل بكثير من الأمهات اللاتي تعرضن لإجهاد الاهتزاز وحده. استغرق حديثو الولادة المعرضون لإجهاد ما قبل الولادة وقتًا أطول للعثور على الربع المستهدف، مما يشير إلى ضعف الذاكرة المكانية، والذي تحسن مع العلاج بمستخلص الكرياتينين. لوحظت زيادة في التفرع الشجيري في الخلايا العصبية CA3 لدى كل من الأمهات المعالجات بمستخلص الكرياتينين وحديثي الولادة. يُحسّن مستخلص الكرياتينين التعلم المكاني لدى الفئران عن طريق تخفيف الضرر العصبي في الحصين CA3 الناتج عن إجهاد الاهتزاز قبل الولادة وانفصال الأم.Background: Prenatal stress detrimentally impacts cognition, behavior, and psychosocial traits. Tinospora cordifolia (TC) is known for its antistress and cognitive enhancement properties. However, its effectiveness against stress induced by maternal separation and vibration is not well-documented. The purpose of the study was to assess the neuroprotective effects of TC on neonatal rats who have experienced the prenatal vibration stress and also stress caused by maternal separation.
Methods: Pregnant Wistar rats in the stressed group experienced three hours of daily vibration stress from 7-16 days of gestation. The treatment group was given 6 mg/kg of TC extract before vibration stress. The neonates were separated from their mother and treated with TC postnatally. At the end treatment period, the rats were subjected to spatial learning task. Following this, animal brains were processed for Golgi cox staining to study the CA3 neuronal arborization.
Results and conclusion: TC-treated mothers showed significantly better spatial learning than those subjected to vibration stress alone. Neonates exposed to prenatal stress took longer time to find the target quadrant, indicating impaired spatial memory, which improved with TC treatment. Increased dendritic branching in CA3 neurons was observed in both TC-treated mothers and neonates. TC extract improves the spatial learning in rats by attenuating the hippocampal CA3 neural damage induced by prenatal vibration stress and maternal separation
TC Insight
No full textIn dit project is er een product geïmplementeerd voor Priva. Priva is een bedrijf dat gespecialiseerd is in klimaatbeheersing in de tuinbouw en kantoorgebouwen. Priva levert regeltechnische software en hardware waarop verschillende componenten zoals CV-ketels, radiatoren en klimaatplafonds kunnen worden aangesloten. De software van Priva regelt vervolgens dat de componenten in deze zogeheten klimaatbeheersingsinstallaties met elkaar kunnen samenwerken en een bepaald binnenklimaat bewerkstelligen. In grote klimaatbeheersingsinstallaties zijn veel componenten van elkaar afhankelijk. Als er in één component een storing optreedt, dan kan deze storing effect hebben op de werking van andere componenten. Deze componenten kunnen als gevolg daarvan weer afwijkend gedrag gaan vertonen. Een uitdaging die vaak voorkomt is dat er afwijkend gedrag wordt vastgesteld in een component, maar dat de daadwerkelijke oorzaak van een probleem in een ander deel van de installatie ligt. Als de afhankelijkheden tussen verschillende componenten inzichtelijk in kaart zouden kunnen worden gebracht, dan zou het makkelijker worden om te achterhalen waar precies de oorzaak ligt als er afwijkend gedrag wordt geconstateerd. Deze gedachte vormt het uitgangspunt voor onze opdracht. In ons uiteindelijke product is het mogelijk om van een klimaatbeheersingsinstallatie de afhankelijkheden tussen verschillende componenten weer te geven. Deze informatie is zowel in een voor computers makkelijk verwerkbaar formaat alsook visueel exporteerbaar. Omdat deze software meer inzicht geeft in de werking van klimaatbeheersingsinstallaties is deze gedoopt tot TC Insight. Er is in het ontwikkelproces gebruikt gemaakt van Test Driven Development, een methode die goede designkeuzes afdwingt en testbare code oplevert. Verder is de software iteratief ontwikkeld volgens de Scrum ontwikkelmethode. Deze methode gaf de opdrachtgever een goed beeld van de bezigheden van het ontwikkelteam en gaf de mogelijkheid om vroeg in het proces feedback te geven zodat deze snel verwerkt kon worden.Software TechnologyElectrical Engineering, Mathematics and Computer Scienc
Model TC-497 Overland Train MkII
No full textPhotograph of the Model TC-497 Overland Train Mkii, the largest and most powerful of all the "land trains" produced by LeTourneau. The TC-497 was built for the U.S. Army to transport cargo in the Arctic under a wide variety of road conditions, according to author Eric Orlemann. It contained nine cargo trailers, a control car and two trailing power units. The TC-497 weighed 135 tons. Its overall length was about 527 feet
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