Separation of oil drops from produced water using a slotted pore membrane

Microfiltration is one of the most important processes in membrane sciences that can be used for separating drops/particles above 1 µm. Depth microfiltration membranes retain drops/particles inside the surface of the membrane, the process is expensive and membranes quickly become fouled. On the other hand, surface microfiltration membranes stop drops/particles on the surface of the membrane and the process is less fouling. Higher permeate flux and lower trans-membrane pressure is obtained with a shear enhanced microfiltration technique. Production of specific size of drops and stability of the drops are very important in testing the microfiltration of crude oil drops/water emulsions. Oil drops from 1-15 µm were produced with a food blender, operated at its highest speed for the duration of 12 mins. In addition, vegetable oil drops were stabilised with 1% polyvinyl alcohol (PVA), Tween 20 and gum Arabic, stability was assessed on the basis of consistency in the size distribution and number of drops in each sample analysed at 30 mins interval. A slotted pore Nickel membrane with the slot width and slot length of 4 and 400 µm respectively has been used in the filtration experiments. The slot width to the slot length ratio (aspect ratio) of the used membrane is 100. Vibrating the membrane at various frequencies created shear rates of different intensities on the surface of the membrane. Membrane with a tubular configuration is preferred over the flat sheet because it is easy to control in-case of membrane oscillations both at lab and industrial scale. Besides this, a tubular membrane configuration provides a smaller footprint as compared to the flat sheet. The influence of applied shear rate on slots/pore blocking has been studied. Applying shear rate to the membrane reduced the blocking of the slots of the membrane; and reduction of slots blocking is a function of the applied shear rate. At higher shear rate, lower blocking of the slots of the membrane was verified by obtaining lower trans-membrane pressure for constant rate filtration. The experiments are in reasonable agreement with the theoretical blocking model. Divergence of the experimental data from the theory may be due to involvement of deforming drops in the process. During microfiltration of oil drops, the drops deform when passing through the slots or pores of the membrane. Different surfactants provided different interfacial tensions between the oil and water interface. The influence of interfacial tension on deformation of drops through the slots was studied. The higher the interfacial tension then the lower would be the deformation of drops through the slots. A mathematical model was developed based on static and drag forces acting on the drops while passing the membrane. The model predicts 100% cut-off of drops through the membrane. Satisfactory agreement of the model with the experiments shows that the concept of static and drag force can be successfully applied to the filtration of deformable drops through the slotted pore membranes. Due to the applied shear rate, inertial lift migration velocities of the drops away from the surface of the membrane were created. Inertial lift velocities are linear functions of the applied shear rate. A mathematical model was modified based on inertial lift migration velocities. The critical radius of the drops is the one above which drops cannot pass through the surface of the membrane into the permeate due to the applied shear rate and back transport. The model is used as a starting point and is an acceptable agreement with the experiment. The model can be used to predict the 100% cut-off value for oil drops filtration and a linear fit between this value and the origin on a graph of grade (or rejection) efficiency and drop size to slot width ratio was used to predict the total concentration of dispersed oil left after filtration. Hence, it is shown how it is possible to predict oil discharge concentrations when using slotted filters

Micro-econometric Analysis of Impact of Remittances on Household’s Welfare: Empirical Evidence from District Peshawar

The present study has been conducted in the year 2010 in district Peshawar to assess the impact of inflow of remittances on household’s welfare. The concept welfare was measured in terms of consumption expenditures of the household. A sample of 60 household was interviewed using snowball sampling combined with the convenient sampling technique. A regression model which was a mixture of direct elasticity and semi-elasticity was used to quantify the relationships. Apart from inflow of remittances (lnremt), three control variables (i.e. years of schooling of the household’s head – edu, age of household’s head – age & family size – fz) were employed to standardize the impact. Controlling for edu, age & edu, this paper conclude that inflow of remittances enhance household’s welfare. All control variables have theoretically correct positive signs. These results were statistically significant and results showed no major econometric problems that can influence statistical inference derived from the model. So it is highly recommended, in light of the present study, that govt. of Pakistan should take all possible steps to export labors abroad. It has dual positive impacts, one enhancing household’s prosperity (welfare) and other reducing unemployment at local level.

OUTCOME AND ROOTS OF EARLY MARRIAGES IN GILGIT-BALTISTAN: A QUANTITATIVE DESCRIPTIVE STUDY

The aim of this study was to find out the causes and outcome of the early marriages in the light of victims and gatekeepers observations. However, one-third of under-aged girls in the developing countries are married before the age of 18 years. Although in Northern areas of Pakistan, early marriage is a very common problem in both gender, especially, in Gilgit-Baltistan and the ratio is higher than any other part of the country. Moreover, in this region, early marriage is prevailed due to traditional customs, religious dominance and supernatural evil. The present study chose two categories, first category for victims which includes respondents of age group from 10 to 40 years old and married before 18 years of age. The second category was chosen for interpretation of the community gatekeepers. We utilized a quantitative survey method to collect data from each district and examined 200 sample. A sample is divided into two groups, the victim's group includes 150 respondents and the group of gatekeepers includes 50 sample size. The tailor-made close-ended questionnaire was designed for the collection of data. Beside this, a Likert scale was also used for Professionals.  There is a need to take some serious steps to eliminate this social disease which promotes the illiteracy, poverty, crime, economic burden, terrorism, domestic violence and rapid increase in population which is surmounting challenges in the pathway of regional development. Early marriage has psychological, physical and economic consequences; most girls remain unable to complete their primary and secondary education and also have the negative impact on their health

Determination of Acute Toxicity of Copper and Cobalt for \u3cem\u3eTilapia nilotica\u3c/em\u3e

During the present investigation, the 96-hr LC50 and lethal concentrations of copper and cobalt for Tilapia nilotica were determined under controlled laboratory conditions at constant pH (7.25), total hardness (255 mgL-1) and temperature (30 °C). During acute toxicity studies, the physico-chemical parameters of water viz. temperature, pH, dissolved oxygen, electrical conductivity, carbon dioxide, total ammonia, calcium, sodium, magnesium, potassium and total hardness were monitored at 12-hr intervals for each test. Fish were exposed to different concentrations of copper and cobalt, separately, starting from zero with an increment of 0.05 and 0.5 mgL-1. After 96-hr exposure of various concentrations of each metal, the fish mortality data were recorded with three replicates for each concentration. The 96-hr LC50 and lethal concentrations for each metal was computed by using Probit analyses method at 95% confidence interval. The 96-hr LC50 and lethal concentrations of copper for Tilapia nilotica were computed as 25.00±0.65 and 47.56±1.18 mg L-1, respectively. However, the tolerance limits of fish for cobalt, in terms of 96-hr LC50 and lethal concentrations were calculated as 96.14±0.58 and 178.46±2.04, respectively. The tolerance limits of fish for both copper and cobalt varied significantly in terms of 96-hr LC50 and lethal concentrations. However, fish were significantly more tolerant to cobalt than that of copper. With the increase in metallic ion concentration of the test media (water), the level of ammonia and carbon dioxide increased, while that of dissolved oxygen decreased constantly. Total ammonia of the test media showed significantly direct relationship with carbon dioxide while the same remained significantly negative with dissolved oxygen indicating decrease in oxygen consumption by the fish under metallic ion stress, at different concentrations of copper and cobalt that enhanced the ammonia excretion by the fish

Mathematical Model for Image Restoration Based on Fractional Order Total Variation

This paper addresses mathematical model for signal restoration based on fractional order total variation (FOTV) for multiplicative noise. In alternating minimization algorithm the Newton method is coupled with time-marching scheme for the solutions of the corresponding PDEs related to the minimization of the denoising model. Results obtained from experiments show that our model can not only reduce the staircase effect of the restored images but also better improve the PSNR as compare to other existed methods

Deep Learning Methods for Malware and Intrusion Detection: A Systematic Literature Review

Android and Windows are the predominant operating systems used in mobile environment and personal computers and it is expected that their use will rise during the next decade. Malware is one of the main threats faced by these platforms as well as Internet of Things (IoT) environment and the web. With time, these threats are becoming more and more sophisticated and detecting them using traditional machine learning techniques is a hard task. Several research studies have shown that deep learning methods achieve better accuracy comparatively and can learn to efficiently detect and classify new malware samples. In this paper, we present a systematic literature review of the recent studies that focused on intrusion and malware detection and their classification in various environments using deep learning techniques. We searched five well-known digital libraries and collected a total of 107 papers that were published in scholarly journals or preprints. We carefully read the selected literature and critically analyze it to find out which types of threats and what platform the researchers are targeting and how accurately the deep learning-based systems can detect new security threats. This survey will have a positive impact on the learning capabilities of beginners who are interested in starting their research in the area of malware detection using deep learning methods. From the detailed critical analysis, it is identified that CNN, LSTM, DBN, and autoencoders are the most frequently used deep learning methods that have effectively been used in various application scenarios

Shear enhanced microfiltration and rejection of crude oil drops through a slotted pore membrane including migration velocities

Shear enhanced microfiltration of crude oil/water emulsion is investigated and the effect of an applied shear rate on the rejection of droplets by the membrane is reported. Applying vibration provides shear rate at the membrane surface leading to shear-induced migration and an inertial lift of drops/particles. Both phenomena tend to move the droplets away from the membrane surface. The shear-induced migration and inertial lift increase with increasing of the shear rate. A mathematical model is presented to account for the presence of both phenomena. The developed model is used for theoretical prediction of 100% cut-off of crude oil droplets by the membrane with, and with-out, vibration applied. A satisfactory agreement of the model predictions with experimental data shows that the model can be successfully used for a theoretical prediction of 100% cut-off of droplets by slotted pore membranes. Rejection of droplets increased with applying shear rate: at 8000 s-1 shear rate and 200 l m-2 hr-1 flux rate 3 to 4 μm radius droplets were almost completely rejected reducing 400 ppm of crude in the feed to 7 ppm in the permeate

Stability and deformation of oil droplets during microfiltration on a slotted pore membrane

The effect of interfacial tension between two fluids, on the passage and rejection of oil droplets through slotted pore membranes is reported. A mathematical model was developed in order to predict conditions for 100% cut-off of oil droplets through the membrane as a function of permeate flux rate. Good agreement of theoretical predictions with experimental data shows that the model can be applied to the filtration of deformable droplets through slotted pore membranes. At high interfacial tension (40 mN/m) with lower flux (200 l m−2 hr−1)droplets of crude oil (27 API) were 100% rejected at droplet diameter 4.3 μm using a 4 μm slotted pore membrane. At lower interfacial tension (5 mN/m), with the same flux rate, 100% rejection occurred at 10 μm droplet diameter using the same membrane. It was also found that the droplet rejection efficiency below the 100% cut-off was roughly linear with drop size, down to zero rejection at zero drop diameter. Hence, the model, coupled with this approximate correlation, can be used to predict dispersed oil drop concentration from a known feed drop size distribution