8,117 research outputs found
An Overview of Mobile Ad Hoc Networks for the Existing Protocols and Applications
Mobile Ad Hoc Network (MANET) is a collection of two or more devices or nodes
or terminals with wireless communications and networking capability that
communicate with each other without the aid of any centralized administrator
also the wireless nodes that can dynamically form a network to exchange
information without using any existing fixed network infrastructure. And it's
an autonomous system in which mobile hosts connected by wireless links are free
to be dynamically and some time act as routers at the same time, and we discuss
in this paper the distinct characteristics of traditional wired networks,
including network configuration may change at any time, there is no direction
or limit the movement and so on, and thus needed a new optional path Agreement
(Routing Protocol) to identify nodes for these actions communicate with each
other path, An ideal choice way the agreement should not only be able to find
the right path, and the Ad Hoc Network must be able to adapt to changing
network of this type at any time. and we talk in details in this paper all the
information of Mobile Ad Hoc Network which include the History of ad hoc,
wireless ad hoc, wireless mobile approaches and types of mobile ad Hoc
networks, and then we present more than 13 types of the routing Ad Hoc Networks
protocols have been proposed. In this paper, the more representative of routing
protocols, analysis of individual characteristics and advantages and
disadvantages to collate and compare, and present the all applications or the
Possible Service of Ad Hoc Networks.Comment: 24 Pages, JGraph-Hoc Journa
Impact of Carbon Dioxide Trapping on Geological Storage
If we are to avoid potentially dangerous climate change, we need to capture and store
CO2 emitted by fossil-fuel burning power stations and other industrial plants [123].
Saline aquifers provide the largest potential for storage and the widest geographical
spread [66]. Subsequent leakage of CO2 into the atmosphere, even over hundreds of
years, would render any sequestration scheme inefficient. However, based on the
experience of the oil and gas industry, there is a good understanding of trapping
mechanisms that take place in geological formations.
Carbon capture and storage (CCS), where carbon dioxide, CO2, is collected from
industrial sources and injected underground is one way to mitigate atmospheric
emissions of this major greenhouse gas (GHG). Possible sites to accommodate CO2
storage are saline aquifers and oil reservoirs. These two types of location are
considered for two reasons: the enormous storage potential in aquifers and the
additional hydrocarbon production that could be produced by oil reservoirs. It is
important that the injection scheme is designed such that the CO2 is safely stored and
will not escape to the surface. Residual trapping offers a potentially quick and effective
alternative method by which a non-wetting phase is rendered immobile as recent
modelling has suggested that up to 90% of CO2 can be effectively immobilised by
residual trapping in a short (years to decades) timescale [133].
There are only a few experimental measurements of capillary trapping in
unconsolidated media in the literature. This is because the experimental measurements
of multi-phase flow are extremely difficult to perform and the results are frequently not
reliable at low saturations [119]. Most of the studies concentrate on trapped gas and
rather than the residual saturation of a liquid phase: CO2 stored underground will be
super-critical and liquid-like. In this work, we focus on measuring reliably and precisely
residual saturations for both two- and three-phase flow covering the entire saturation
range, including very low residual saturations.
We performed drainage-imbibition and buoyancy-driven experiments for two-phase
flow (oil-water and gas-water systems) and three-phase gravity drainage experiments
for an oil-gas-water system on unconsolidated sand (LV60).
The measured porosity of the sand was 0.37 obtained from three replicates (each
replicate is a completely new experiment). The mean absolute permeability was 3.1 x
10-11 m2. The initial water saturation (Swi), residual oil saturation (Sor) and residual gas
saturation (Sgr) were measured by two methods, namely mass balance (MB) and volume
balance (VB). Mean values were 0.27 for Swi, 0.13 for Sor, and 0.14 for Sgr. Accuracy was
maintained to be within 0.1% for every measurement.
The buoyancy-driven experiments results show that Sor and Sgr are 11% and 14%
respectively and generally lower than consolidated media. The trapped saturations
initially rise linearly with initial saturation to a maximum value, followed by a constant
residual as the initial saturation increases further. This behaviour is not predicted by the
most commonly-used empirical models, but is physically consistent with poorly
consolidated media where most of the larger pores can easily be invaded at relatively
low saturation and there is, overall, relatively little trapping. The best match to our
experimental data was achieved with the trapping model proposed by Aissaoui [2].
The three-phase gravity drainage experiments results show that for high initial gas
saturations more gas can be trapped in the presence of oil than in a two-phase (gaswater)
system. This is unlike previous measurements on consolidated media, where the
trapped gas saturation is either similar or lower to that reached in an equivalent twophase
experiment. The maximum residual gas saturation is over 20%, compared to 14%
for two-phase flow. For lower initial gas saturation, the amount of trapping follows the
initial-residual trend seen in two-phase experiments, although some values lie below the
two-phase correlation These results are discussed in relation to pore-scale
displacement processes and compared to literature values – mainly on consolidated
media – that find that both gas and oil residuals are lower in three-phase than twophase
flow [32, 52, 70, 81, 95, 97, 101, 108, 143-145].
This work implies that CO2 injection in poorly consolidated media would lead to rather
poor storage efficiencies, with at most 4-6% of the rock volume occupied by trapped
CO2; this is at the lower end of the compilation of literature results shown in Fig. 5.2.
Using the Land correlation to predict the behaviour would tend to over-estimate the
degree of trapping except for high initial saturations. The presence of a third phase
(such as in an oil field, for instance) may improve the trapping efficiency
Bis(4,6-diaminopyrimidin-2-yl) disulfide dimethyl sufoxide disolvate
The title compound, C8H10N8S2·2C2H6SO, was obtained unintentionally during an attempt to prepare a thiol-ate derivative of trimethyl-tin. The complete disulfide mol-ecule is generated by twofold rotation symmetry and the C - S - S - C torsion angle around the S - S bond is -85.70 (10)°. The mol-ecules are connected via N - H⋯N hydrogen bonds into strongly corrugated layers parallel to (001), generating an R 2 2(8) motif. The solvent mol-ecule, which exhibits minor disorder of its S atom [site occupancies = 0.9591 (18) and 0.0409 (18)], is linked to this layer via a pair of N - H⋯O inter-actions
Rancang Bangun Robot Pemantau Wireless Berbasis Mikrokontroler ATMega8535 Menggunakan Bahasa Basic
Penelitian ini merancang dan membuat robot pemantau yang dapat dikendalikan secara wireless dengan frekuensi 35 MHz menggunakan remot kontrol berupa stick PS dan hasil pantauan kamera pada robot ditampilkan di TV kecil sebagai monitor melalui A/V wireless dengan frekuensi 2,4 GHz sehingga lebih eksibel dalam penggunaan dan mudah dibawa kemanapun, dibandingkan pada penelitian sebelumnya yang masih belum maksimal dengan menggunakan PC dimana pengendalian robot melalui keyboard dan hasil pantauan kamera pada robot ditampilkan dimonitor. Sistem dikendalikan menggunakan program Basic Compiler (BASCOM) dan memanfaatkan kemampuan mikrokontroler ATMega8535 dalam pengendalian 4 buah motor servo berdasarkan 4 buah perintah dari transmitter terhadap receiver sebagai masukan mikrokontroler. Pelaksanaan penelitian dilakukan di Laboratorium Elektronika dan Instrumentasi MIPA Fisika UNSRI. Tahapan penelitian yaitu perancangan dan desain perangkat keras dan perangkat lunak, perakitan, penerapan perangkat lunak pada robot, uji coba robot. Dari hasil perancangan dan pembuatan software dan hardware yang telah dibuat maka diperoleh hasil pengujian jarak jangkauan dan respon penerimaan data pada robot, pada beda ruangan menjangkau jarak 200 cm dan pada area terbuka menjangkau jarak 300 cm untuk gerakan maju, mundur, serta berbelok kanan dan kiri. Pada pengujian performa dan kendali robot diperoleh hasil pengujian waktu tempuh dan kecepatan robot berjalan maju sejauh 300 cm dan mundur sejauh 200 cm. Sedangkan pada pengujian waktu tempuh robot berbelok kiri dan kanan, robot ini bisa berbelok bahkan berputar searah jarum jam dari 0°-360° dan berlawanan arah dengan jarum jam dari 0°-360°
Measuring the Impact of Higher Education in Promoting Sustainable Development Goals: Analysis of the Arab universities’ performance
Sustainability's global importance has amplified the role of universities in achieving the UN Sustainable Development Goals (SDGs) through research, education, and community engagement. Aim: This study aims to provide valuable insights into the role of Arab universities in promoting sustainability within the context of global higher education. Approach and methods: This study analyzes the performance of 200 universities from 15 Arab countries in the THE IMPACT Rankings. Their performance was compared to 135 universities from three of the leading world-class higher education systems: Canada, UK, and USA. Results: A global demand for sustainable development, Arab universities face challenges in improving their contributions to the SDGs and sustainability rankings. Despite the impressive growth in the participation of Arab universities in THE IMPACT Rankings yet lags in quality and impact of Arab universities contributions towards SDGs. Conclusion: The policy implications underscore the importance of institutional commitment to sustainability in Arab universities, urging the alignment of policies, funding, and curriculum with the United Nations Sustainable Development Goals (SDGs). Arab universities need to bridge performance gaps, promote green initiatives, and contribute effectively to the achievement of SDGs while recognizing the diverse socio-economic context and priorities of the Arab region.Globalne znaczenie zrównoważonego rozwoju spotęgowało rolę uniwersytetów w realizacji Celów Zrównoważonego Rozwoju (SDG) ONZ poprzez badania, edukację i zaangażowanie społeczności. Cel: Celem tego badania jest dostarczenie cennych spostrzeżeń dotyczących roli uniwersytetów arabskich w promowaniu zrównoważonego rozwoju w kontekście globalnego szkolnictwa wyższego. Podejście i metody: Badanie to analizuje wyniki 200 uniwersytetów z 15 krajów arabskich w rankingach THE IMPACT. Ich wyniki porównano z 135 uniwersytetami z trzech czołowych światowych systemów szkolnictwa wyższego: Kanady, Wielkiej Brytanii i USA. Wyniki: W obliczu globalnego zapotrzebowania na zrównoważony rozwój, uniwersytety arabskie napotykają wyzwania w poprawie swojego wkładu w SDG i rankingi zrównoważoności. Pomimo imponującego wzrostu udziału uniwersytetów arabskich w rankingach THE IMPACT, jest jeszcze wiele do zrobienia w zakresie jakości i wpływu ich wkładu w SDG. Wnioski: Implikacje polityczne podkreślają znaczenie zobowiązania instytucjonalnego do zrównoważonego rozwoju w uniwersytetach arabskich, nawołując do dostosowania polityk, finansowania i programów nauczania do Celów Zrównoważonego Rozwoju (SDG) ONZ. Uniwersytety arabskie muszą zniwelować luki w wynikach, promować inicjatywy zielone i efektywnie przyczyniać się do osiągnięcia SDG, uwzględniając różnorodny kontekst społeczno-ekonomiczny i priorytety regionu arabskiego.
 
Middle Miocene ostracoda from northern Iraq
The Ostracoda from nine sections of the Lower Fars Formation, Northern Iraq, Tel-Hajer well-1, Sheikh Ibrahim locality, Dohuk locality, Sheikhan locality, Bashiqa locality, Kirkuk well-208, Bai-Hassan well-33, Hamrin well-2 and the Naft Khana well-34, have been studied in detail.One hundred and nine Ostracod species/subspecies belonging to 50 genera/subgenera are described, of which one genus, one subgenus and 70 species are new. Five species are assigned to species previously described from western India. Five species are compared with other species from W. India, Iran, Turkey and France. Three species are regarded as having affinities with new species described in this thesis and 26 species are left under open nomenclature mainly because of lack of material or the impossibility of observing the internal details.Biostratigraphically, the Lower Fars Formation in the Sinjar area is divided into three Assemblage Zones, these zones are applicable only to N. Iraq, but make a starting point for future work in the area. In the Kirkuk area, the saliferous beds proved completely barren, but the upper Red, Seepage and Transition beds yield Ostracods although the assemblages recognised are at present only regarded as tentative, because the samples are ditch cuttings.Palaeoecology is discussed in terms of oxygenation, alaeoclimate, salinity and the trends in the depositional environment of the Lower Fars Formation.The affinities of the present genera and species are discussed from a palaeogeographical view point in relation to the adjacent and related regions. Three Miocene Ostracod provinces are proposed, namely a western India province, a Zagros shelf province and a southeast Turkey province
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