Experimental investigation of two-phase pressure drop in a microchannel

This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.An experimental study of two-phase pressure drop in a horizontal circular microchannel is presented in this paper. Test tube is made of fused silica having an internal diameter of 781μm with a total length of 261mm and a heated length of 191mm.The external surface of the test tube is coated with an electrically conductive thin layer of ITO (Indium Tin Oxide) for direct heating of test section. Refrigerant R134a was used as the working fluid and mass flux during the experiments was varied from 100 to 650 kg/m2sec. Experiments were performed at a system pressure of 7.70 bar (corresponding to saturation temperature of 30oC). Two-phase frictional pressure drop characteristics with different mass flux, vapour fraction and heat flux were explored in detail. Finally, the prediction capability of well known available correlations in the literature, developed for macrochannels and others especially developed for microchannels was also checked. The homogeneous model predicts the data fairly well with a mean absolute deviation (MAD) of 19% and 69% of data within ±20% error band. The Müller-Steinhagen and Heck (1986) correlation developed for macrochannels predicts the data with a MAD of 19% and 61% of data within ±20% error band. The Mishima and Hibiki (1996) correlation, developed for microchannels, also shows fairly good approximation of the data with MAD of 19% and 57% of data within ±20% error band

Upaya Meningkatkan Motivasi Belajar Matematika Melalui Metode Bermain Peran Pada Siswa Kelas II SD Negeri 6 Sindurejo Tahun Pelajaran 2012 / 2013

Tujuan penelitian ini untuk meningkatkan motivasi belajar matematika melalui metode bermain peran pada siswa kelas 2 SD Negeri 6 Sindurejo Kecamatan Toroh Kabupaten Grobogan Jawa Tengah pada Tahun 2012 /2013. Pada saat kegiatan pembelajaran pra siklus, siswa tidak memperhatikan penjelasan guru, kurang antusias, kurang aktif, dan perhatian siswa terpecah pada hal lain. Metode penelitian yang dilakukan untuk mengatasi masalah tersebut ialah dengan menggunakan metode bermain peran yang melibatkan unsur sosial dalam pembelajaran sehingga melibatkan aktivitas seluruh siswa. Hasil penelitian ini menunjukkan secara teoritik dan empirik melalui metode bermain peran dapat meningkatkan motivasi belajar matematika. Hal ini dibuktikan pada pra siklus dari 18 siswa yang motivasinya meningkat hanya 28 %, naik menjadi 33 % pada siklus I dan 94% pada siklus II. Data itu menunjukkan tindakan perbaikan telah mencapai keberhasilan karena sudah melampaui indikator pencapaian peningkatan motivasi yang ditetapkan yaitu sebesar ≥80%

Lip syncing method for realistic expressive 3D face model

Lip synchronization of 3D face model is now being used in a multitude of important fields. It brings a more human, social and dramatic reality to computer games, films and interactive multimedia, and is growing in use and importance. High level of realism can be used in demanding applications such as computer games and cinema. Authoring lip syncing with complex and subtle expressions is still difficult and fraught with problems in terms of realism. This research proposed a lip syncing method of realistic expressive 3D face model. Animated lips requires a 3D face model capable of representing the myriad shapes the human face experiences during speech and a method to produce the correct lip shape at the correct time. The paper presented a 3D face model designed to support lip syncing that align with input audio file. It deforms using Raised Cosine Deformation (RCD) function that is grafted onto the input facial geometry. The face model was based on MPEG-4 Facial Animation (FA) Standard. This paper proposed a method to animate the 3D face model over time to create animated lip syncing using a canonical set of visemes for all pairwise combinations of a reduced phoneme set called ProPhone. The proposed research integrated emotions by the consideration of Ekman model and Plutchik’s wheel with emotive eye movements by implementing Emotional Eye Movements Markup Language (EEMML) to produce realistic 3D face model. © 2017 Springer Science+Business Media New Yor

An energy efficient interference-aware routing protocol for underwater WSNs

Interference-aware routing protocol design for underwater wireless sensor networks (UWSNs) is one of the key strategies in reducing packet loss in the highly hostile underwater environment. The reduced interference causes efficient utilization of the limited battery power of the sensor nodes that, in consequence, prolongs the entire network lifetime. In this paper, we propose an energy-efficient interference-aware routing (EEIAR) protocol for UWSNs. A sender node selects the best relay node in its neighborhood with the lowest depth and the least number of neighbors. Combination of the two routing metrics ensures that data packets are forwarded along the least interference paths to reach the final destination. The proposed work is unique in that it does not require the full dimensional localization information of sensor nodes and the network total depth is segmented to identify source, relay and neighbor nodes. Simulation results reveal better performance of the scheme than the counterparts DBR and EEDBR techniques in terms of energy efficiency, packet delivery ratio and end-to-end delay

A novel pathogenic mutation of the CYP27B1 gene in a patient with vitamin D-dependent rickets type 1: a case report

BACKGROUND: Rickets can occur due to Vitamin D deficiency or defects in its metabolism. Three rare genetic types of rickets with different alterations of genes have been reported, including: Vitamin D dependent rickets type 1, Vitamin D dependent rickets type 2 or also known as Vitamin D resistant rickets and 25 hydroxylase deficiency rickets. Vitamin D dependent rickets type 1 is inherited in an autosomal recessive pattern, and is caused by mutations in the CYP27B1 gene encoding the 1α-hydroxylase enzyme. We report here a new mutation in CYP27B1, which lead to Vitamin D dependent rickets type 1. CASE PRESENTATION: We report on a 13-month-old Arabic Saudi girl with Vitamin D dependent rickets type 1 presented with multiple fractures and classic features of rickets. A whole exome sequencing identified a novel pathogenic missense mutation (CYP27B1:Homozygous c.1510C > T(p.Q504X)) which results in a protein truncating alteration. Both parents are heterozygous carriers of the mutation. Based on data search in Human Gene Mutation Database, 63 CYP27B1 alterations were reported: only 28.6% are protein truncating (5 nonsense, 13 frameshift insertions/deletions, 0 gross deletions), while 61.9% are non-truncating (38 missense, 1 small in-frame insertions/deletion), and 9.5% are possible protein-truncating (5 splice, 1 regulatory). CONCLUSION: The deleterious effect of this alteration, which was the only mutation detected in the CYP27B1 common gene of Vitamin D dependent rickets type 1 in the proband, and its autosomal recessive inheritance fashion, both support a pathogenic nature of this mutation as the cause of Vitamin D dependent rickets type 1

The state of ambient air quality in Pakistan—a review

Background and purpose: Pakistan, during the last decade, has seen an extensive escalation in population growth, urbanization, and industrialization, together with a great increase in motorization and energy use. As a result, a substantial rise has taken place in the types and number of emission sources of various air pollutants. However, due to the lack of air quality management capabilities, the country is suffering from deterioration of air quality. Evidence from various governmental organizations and international bodies has indicated that air pollution is a significant risk to the environment, quality of life, and health of the population. The Government has taken positive steps toward air quality management in the form of the Pakistan Clean Air Program and has recently established a small number of continuous monitoring stations. However, ambient air quality standards have not yet been established. This paper reviews the data being available on the criteria air pollutants: particulate matter (PM), sulfur dioxide, ozone, carbon monoxide, nitrogen dioxide, and lead. Methods: Air pollution studies in Pakistan published in both scientific journals and by the Government have been reviewed and the reported concentrations of PM, SO2, O3, CO, NO2, and Pb collated. A comparison of the levels of these air pollutants with the World Health Organization air quality guidelines was carried out. Results: Particulate matter was the most serious air pollutant in the country. NO2 has emerged as the second high-risk pollutant. The reported levels of PM, SO2, CO, NO2, and Pb were many times higher than the World Health Organization air quality guidelines. Only O3 concentrations were below the guidelines. Conclusions: The current state of air quality calls for immediate action to tackle the poor air quality. The establishment of ambient air quality standards, an extension of the continuous monitoring sites, and the development of emission control strategies are essential. © Springer-Verlag 2009

Sustainable deltas in the Anthropocene

What are the possible trajectories of delta development over the coming decades? Trajectories will be determined by the interactions of biophysical trends such as changing sediment supplies, subsidence due to compaction of sediment and climate change, along with key socio-economic trends of migration and urbanisation, agricultural intensification, demographic transition, economic growth and structural change of the economy. Knowledge and understanding of plausible trajectories can inform management choices for deltas in the Anthropocene, including new policy perspectives and innovative adaptation. The emergence of visionary delta management plans in some large deltas, such as the Bangladesh Delta Plan 2100, is an important and necessary component. This chapter synthesises the state of knowledge and highlights key elements of science that will inform decisions on future management of deltas.<br/

Quantum corrections and black hole spectroscopy

In the work \cite{BRM,RBE}, black hole spectroscopy has been successfully reproduced in the tunneling picture. As a result, the derived entropy spectrum of black hole in different gravity (including Einstein's gravity, Einstein-Gauss-Bonnet gravity and Ho\v{r}ava-Lifshitz gravity) are all evenly spaced, sharing the same forms as $S_n=n$, where physical process is only confined in the semiclassical framework. However, the real physical picture should go beyond the semiclassical approximation. In this case, the physical quantities would undergo higher-order quantum corrections, whose effect on different gravity shares in different forms. Motivated by these facts, in this paper we aim to observe how quantum corrections affect black hole spectroscopy in different gravity. The result shows that, in the presence of higher-order quantum corrections, black hole spectroscopy in different gravity still shares the same form as $S_n=n$, further confirming the entropy quantum is universal in the sense that it is not only independent of black hole parameters, but also independent of higher-order quantum corrections. This is a desiring result for the forthcoming quantum gravity theory.Comment: 14 pages, no figure, use JHEP3.cls. to be published in JHE

3-D Printed Radar Absorber with Meta-material Features for X-band Application

This paper presents a structured radar absorber with metamaterial features based on graphite SLS composite. The unit cell of the proposed design was simulated on COMSOL Multiphysics to determine its frequencydependent absorption characteristics and fabricated using low-cost selective laser sintering 3-D printing technology. The measurement and simulation results showed an effective absorption bandwidth of 1.04 GHz and 2.08 GHz respectively. The optimized structure however, revealed broadband absorption in a frequency range between 8.35 to 12.20 GHz (X band) under normal incidence. Besides, the absorption performance under different polarizations and incident angles were investigated. Results indicated that the absorber exhibits polarization indifference and high absorptivity at a wide angle of incidence. The advantages of low cost, ultra-broad operating band, wide-angle feature, and polarization insensitivity made the proposed absorber a promising candidate in military and civilian applications

Back reaction, emission spectrum and entropy spectroscopy

Recently, an interesting work, which reformulates the tunneling framework to directly produce the Hawking emission spectrum and entropy spectroscopy in the tunneling picture, has been received a broad attention. However, during the emission process, most related observations have not incorporated the effects of back reaction on the background spacetime, whose derivations are therefore not the desiring results for the real physical process. With this point as a central motivation, in this paper we suitably adapt the \emph{reformulated} tunneling framework so that it can well accommodate the effects of back reaction to produce the Hawking emission spectrum and entropy spectroscopy. Consequently, we interestingly find that, when back reaction is considered, the Parikh-Wilczek's outstanding observations that, an isolated radiating black hole has an unitary-evolving emission spectrum that is \emph{not} precisely thermal, but is related to the change of the Bekenstein-Hawking entropy, can also be reproduced in the reformulated tunneling framework, meanwhile the entropy spectrum has the same form as that without inclusion of back reaction, which demonstrates the entropy quantum is \emph{independent} of the effects of back reaction. As our final analysis, we concentrate on the issues of the black hole information, but \emph{unfortunately} find that, even including the effects of back reaction and higher-order quantum corrections, such tunneling formalism can still not provide a mechanism for preserving the black hole information.Comment: 16 pages, no figure, use JHEP3.cls. to be published in JHE