Measurement of streaming potential coupling coefficient in sandstones saturated with natural and artificial brines at high selenity

We report experimental measurements of the streaming potential coupling coefficient in sandstones saturated with NaCl-dominated artificial and natural brines up to 5.5 M (321.4 g L−1 of NaCl; electrical conductivity of 23 S m−1). We find that the magnitude of the coupling coefficient decreases with increasing brine salinity, as observed in previous experimental studies and predicted by models of the electrical double layer. However, the magnitude of the coupling coefficient remains greater than zero up to the saturated brine salinity. The magnitude of the zeta potential we interpret from our measurements also decreases with increasing brine salinity in the low-salinity domain (0.4 M). We hypothesize that the constant value of zeta potential observed at high salinity reflects the maximum packing of counterions in the diffuse part of the electrical double layer. Our hypothesis predicts that the zeta potential becomes independent of brine salinity when the diffuse layer thickness is similar to the diameter of the hydrated counterion. This prediction is confirmed by our experimental data and also by published measurements on alumina in KCl brine. At high salinity (>0.4 M), values of the streaming potential coupling coefficient and the corresponding zeta potential are the same within experimental error regardless of sample mineralogy and texture and the composition of the brine

Tanggungjawab Bank Atas Penggunaan Cek Sebagai Alat Pembayaran

Pada zaman yang modern ini semua serba praktis, orang yang melakukan transaksi dengan membutuhkan uang tunai dalam jumlah besar tidak perlu lagi membawa uang tunai. Cek merupakan salah satu kemudahan dalam dunia USAha dan perdagangan. Transaksi dengan menggunakan cek, orang dengan segera memperoleh uang tunai dengan hanya membawa dan menukar cek tersebut ke bank. Dengan menggunakan cek terdapat banyak sekali kemudahan dan sangat banyak memberikan manfaat maka akibatnya banyak orang yang menggunakan cek sebagai alat pembayaran pengganti uang tunai. Dilihat dari segi waktu dan rasa aman dalam melakukan transaksi maka orang lebih memilih menggunakan cek daripada membawa uang tunai dalam jumlah yang besar. Dalam pelaksanaan pembayaran dengan cek tersebut pihak bank terdapat tanggungjawab dalam lalu lintas pembayaran cek tersebut

(Analysis of the proliferating cell nuclear antigen(PCNA) and Ki-67 as proliferating cell markers) Expressions in colorectal carcinoma at HUSM and its relationship with the duke staging system

Proliferating cell nuclear antigen (PCNA) and Ki-67 are the two important molecules expressed by the proliferating cells. They are important during the DNA synthesis. We applied the antibodies (using DAKO EPOS system) against these two proteins to a series of 54 cases of colorectal adenocarcinoma of various Dukes' stages in order to observe the degree of expressions and their relationship with Dukes' stage. Our study showed, regardless of the Dukes' stage almost all cases are strongly expressed PCNA. However we failed to demonstrate the expression of Ki-67. We conclude that expression of PCNA is strong in colorectal carcinoma but the degree of expression has no relationship with the Dukes' stage. Expression of Ki-67 is probably best seen if we use fresh tissue rather than formalin fixed paraffin embedded tissue

Uplink Design in VLC Systems with IR Sources and Beam Steering

The need for high-speed local area networks to meet the recent developments in multimedia and video transmission applications has recently focused interest on visible light communication (VLC) systems. Although VLC systems provide lighting and communications simultaneously from light emitting diodes, LEDs, the uplink channel design in such a system is a challenging task. In this paper, we propose a solution in which the uplink challenge in indoor VLC is resolved by the use of an Infrared (IR) link. We introduce a novel fast adaptive beam steering IR system (FABS-IR) to improve the uplink performance at high data rates while providing security for applications. The goal of our proposed system is to enhance the received optical power signal, speed up the adaptation process and mitigate the channel delay spread when the system operates at a high transmission rate. The channel delay spread is minimised from 0.22 ns given by hybrid diffuse IR link to almost 0.07 ns. At 2.5 Gb/s, our results show that the imaging FABS-IR system accomplished about 11.7 dB signal to noise ratio (SNR) in the presence of multipath dispersion, receiver noise and transmitter mobility

Modelling of precast concrete composite slab using finite and interface elements

This study presents an efficient finite element analysis technique which shows great versatility in modelling of precast composite flooring system subjected to static loadings. The method incorporates sliding and opening in the analysis of composite structures using the interface element which was specifically designed to simulate the actual behaviour at the interfaces between contacting materials. A three-dimensional finite element model of the precast composite slab which exhibits discontinuous behaviour was performed to demonstrate the potential and applicability of the proposed method of analysis. The results of the analysis demonstrate that the overall response of a discontinuous system to external loading is significantly affected by the bonding condition at the interfaces between the contacting materials

Method to reduce the formation of crystallites in ZnO nanorod thin-films grown via ultra-fast microwave heating

© 2018 This paper discusses the nucleation and growth mechanisms of ZnO nanorod thin-films and larger sized crystallites that form within the solution and on surfaces during an ultra-fast microwave heating growth process. In particular, the work focusses on the elimination of crystallites as this is necessary to improve thin-film uniformity and to prevent electrical short circuits between electrodes in device applications. High microwave power during the early stages of ZnO deposition was found to be a key factor in the formation of unwanted crystallites on substrate surfaces. Once formed, the crystallites, grow at a much faster rate than the nanorods and quickly dominate the thin-film structure. A new two-step microwave heating method was developed that eliminates the onset of crystallite formation, allowing the deposition of large-area nanorod thin-films that are free from crystallites. A dissolution-recrystallization mechanism is proposed to explain why this procedure is successful and we demonstrate the importance of the work in the fabrication of low-cost memristor devices