Reinforced composite masonry shear walls

The results of tests of reinforced composite masonry panels subjected to gravity and in-plane shear loads are discussed herein. Eleven walls were tested. Each of the walls was made from two wythes of brick-to-brick or brick-to-block, with a nominal 2-inch collar joint. In the first 10 walls, the collar joint was grouted and reinforced with either welded wire fabric or vertical and horizontal bars. For the last wall, vertical bars in the block openings were used as reinforcement and the collar joint was not grouted. The two wythes for the last wall were connected together using horizontal truss joint reinforcement in the bed mortar. Vertical load was applied first, followed by the in-plane horizontal load while the vertical load was held constant. The loads (either vertical or horizontal) were applied as distributed loads along the top of the wall, which was free to move. (The base of the wall was fixed to the floor.) The wall panels were approximately 4 feet wide, 6 feet high and 9 inches thick;The walls were also analyzed using the finite element technique, and the results were compared with the working stress design and the shear wall equation. A large-scale general purpose computer program developed by Swanson Analysis Systems Inc. of Houston, Pennsylvania (ANSYS) was used considering the wall as a cantilever beam supported at the bottom and free from the top. The two-dimensional plane stress elements were used with different mesh size. A proposed method of analysis is discussed herein;Conclusions and recommendations as a result of this research are discussed herein

Performance of Membrane Bioreactor in the Treatment of High Strength Municipal Wastewater

In some parts of Malaysia, wastewater treatment plants (WWTPs) are located in industrial areas. These WWTPs receive wastewater mostly from these industrial activities regularly or occasionally. Therefore, their biochemical oxygen demand (BOD), chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) are very high. Conventional biological treatment processes are incapable of producing desirable effluent quality with the increasingly stringent discharge requirement. In this study, a laboratory-scale membrane bioreactor (MBR) was used for treating high strength municipal wastewater. Prepared synthetic wastewater samples which represent a high strength municipal wastewater as well as the actual high strength municipal wastewater were used in the study. The developed MBR was operated under different conditions using statistical experimental full factorial design with three factors and three levels. The factors were sludge retention time (SRT), feed temperature (Tf) and organic loading rate (OLR) and their respective levels were 25, 30 and 35 days; 20, 30 and 40 oC; and 1.73, 4.03 and 6.82 kg COD/m3 .d . To evaluate the performance of MBR under the different operating conditions, ten trials were carried out using the prepared synthetic wastewater samples. The MBR could cope with the different operating conditions with high accuracy on the experimental results. Permeate COD, BOD, NH3-N and total suspended solids (TSS) varied from 0 to 32, 0.3 to 13.1, 0.004 to 0.856 and 0 to 26 mg/l respectively. The pH in the aeration tank increased significantly compared to that of the feeding tank. In addition, the increasing pH of the aeration tank was well correlated to that in the feeding tank. (R2 = 0.8336 for low OLR trials and 0.9106 for high OLR trials). To investigate the effects of the different operating conditions on membrane fouling, sustainable time (tsust) was used as a measure to compare the different trials. Within the same OLR level, tsust increased as SRT and Tf increased. Sustainable time was found to decrease as the ratio of mixed liquor volatile suspended solids to mixed liquor suspended solids (MLVSS /MLSS) increased with a correlation coefficient (R2) of 0.808. When MBR was used to treat the actual high strength municipal wastewater, the respective average removal efficiencies of COD, BOD and NH3-N were 98.4, 99.7, and 99.9%. These were found to be comparable with those values obtained from the synthetic wastewater treated by MBR . Empirical models were developed to predict the concentrations of permeate COD, BOD and NH3-N. The predicted values were highly correlated with the observed values (R2 of 0.9188, 0.9111 and 0.9899 respectively for the three parameters mentioned). However the models of COD and BOD were found to be more accurate than the NH3-N model. Future work on the optimization of MLSS concentration and aeration rate as well as the improvement on the techniques for reducing the membrane fouling is recommended

Pilot Plant Studies Using Moringa Oleifera (Kacang Kelor) Seeds As a Primary Coagulant in Surface Water Treatment

Many researchers have used Moringa oleifera (Kacang Kelor) as a primary coagulant, for water treatment. It can also be used as coagulant aid, and floc toughners to either supplement or replace alum, ferric salts and synthetic polymers. The present study involves use of a pilot plant constructed by the author to evaluate the efficiency of Moringa oleifera seeds (25 % extracted seed oil) in treating turbidity of surface water collected from a stream located beside the hydraulic laboratory in the Department of Civil Engineering Universiti Putra Malaysia. Two stages were involved in the preparation of the seeds for the test. The seed wings and coat were first removed and ground to powder using a domestic blender. The second stage was the extraction of 25 % of the seed oil using the Soxhlet. Like the normal water treatment plant, the pilot plant was operated under four stages: coagulation, flocculation, sedimentation and filtration (rapid sand filter). Both conventional treatment (CT) and direct filtration (DF) methods were considered in running the pilot plant tests. Pilot plant tests were carried out three hours per run over whole period of three months. The turbidity, pH, alkalinity and zeta potential as well as the filter head loss were monitored regularly (every 30 minutes) during the test run. Average percentage turbidity removal of 75.4, 88.0, and 96.9 % resulted by DF for the low, moderate and high initial turbidity respectively, whereas CT gave average turbidity removal of 43.9, 93.5, and 95.7 for the same initial turbidity. The optimum dosages 20 and 30 mg/l of Moringa olei/era was applied for low and moderate turbidity respectively whereas for the high turbidity the Moringa oleifera dosage was varied from 50 - 80 mg/l depending on the initial turbidity. One out of eleven trials for CT gave a residual turbidity after filtration lower than 5 NTU. This value agreed with Malaysian guideline of 5 NTU. Eight trials gave a residual turbidity ranged from 8 - 15 NTU, which falls within the WHO maximum level of 25 NTU. 3 trials out of 7 for DF gave a residual turbidity after filtration lower than 5 NTU whereas 4 trials gave a residual turbidity ranged from 6.6 - 11 NTU. Turbidity removal of DF was found to be better than that of CT. Moringa oleifera was found to have no significant effect on pH or alkalinity of the water. Zeta potential of the water was found to decrease after treatment. The maximum filter head loss at depth 40 em was found to be 24 em for CT. In the case of DF the maximum head loss at depth 40 em was found to be 29.3 em for an average turbidity of 230.4 NTU and 70.9 em for an average turbidity of 88.7 NTU. Therefore, oil extracted Moringa oleifera seeds was found to posses a great potential for coagulation as a primary coagulant for treating surface water

Optimal Cooperative Cognitive Relaying and Spectrum Access for an Energy Harvesting Cognitive Radio: Reinforcement Learning Approach

In this paper, we consider a cognitive setting under the context of cooperative communications, where the cognitive radio (CR) user is assumed to be a self-organized relay for the network. The CR user and the PU are assumed to be energy harvesters. The CR user cooperatively relays some of the undelivered packets of the primary user (PU). Specifically, the CR user stores a fraction of the undelivered primary packets in a relaying queue (buffer). It manages the flow of the undelivered primary packets to its relaying queue using the appropriate actions over time slots. Moreover, it has the decision of choosing the used queue for channel accessing at idle time slots (slots where the PU's queue is empty). It is assumed that one data packet transmission dissipates one energy packet. The optimal policy changes according to the primary and CR users arrival rates to the data and energy queues as well as the channels connectivity. The CR user saves energy for the PU by taking the responsibility of relaying the undelivered primary packets. It optimally organizes its own energy packets to maximize its payoff as time progresses

CO2 wettability of rock and implications for core-flooding

Rock became more CO2 wet with increasing pressure, temperature and brine salinities and less CO2 wet with increasing surface roughness - i.e. a lower storage capacity can be inferred for structural trapping. Moreover, we demonstrate that gas densities correlate remarkably well with wettability also a physical model was developed to provide a theoretical framework. Furthermore, the permeability of sandstone samples reduced after injection of brine, CO2-saturated brine or supercritical CO2 at reservoir conditions

Simulation Study on IWAG Assisted by Low Salinity Water Injection for Light Oil Reservoirs

Water alternating gas (WAG) injection is a widely practiced Enhanced Oil Recovery (EOR) technique for light oil reservoirs. On the other hand, various researches have documented that using the Smart water concept can further enhance the oil recovery obtained from water-flooding. Although, there was extensive researches conducted on each of the WAG and the smart water techniques separately, yet there are a very few researches conducted on using the smart water concept as the injection water in WAG technique. Previous laboratory core flooding researches have shown that reducing the salinity of the injection water in miscible WAG process would decrease the ultimate oil recovery. The published literature attributed that to the fact that reducing the salinity of the injection water would increase the solubility of the injected gas in water and thus reducing the amount of available gas to be soluble in oil. Reservoir simulation processes were utilized in order to study the effect of using the smart water as the injection water in IWAG technique for light oil reservoirs. A synthetic model with 7,500 grid cells was used to evaluate the performance of several injection scenarios involving low salinity water and WAG techniques under the conditions of light oil reservoir at the depth of -6,000 ft. with oil API of 45°. The thickness of the reservoir is 30 ft. The simulated results showed that using low salinity water as the injection water in immiscible WAG process would increase the oil recovery by 3.5% of the original oil in place (OOIP) than when using conventional high salinity water for light oil reservoirs. The results obtained from the simulation processes do not contradict the laboratory experiments results because of two main reasons. The first reason is that the simulation operations were based on immiscible WAG processes while the core flooding experiments were based on miscible WAG processes, and the second one is due to the gravity effects. During core flooding operations, gravity effects are minimal, while it was taken in consideration during the simulation processes. Another important discovery by the reservoir simulation operations is that using a slug of low salinity water followed by high salinity drive water has much higher recoveries than conventional high salinity water flooding, and that adjusting the slug size can obtain recoveries almost as high as continuous low salinity water injectio

SYNTHESIS OF POLYMERIZED IONIC LIQUIDS FOR CARBON DIOXIDE CAPTURE

The high level of carbon dioxide (CO2) content in natural gas reserves discovered lately in Malaysia and some other reservoirs around the globe is one of the major issues that are being faced by the industry nowadays. The existing processes for CO2 removal suffer from one main setback i.e., the limitation on the maximum content of CO2 that is allowed in the natural gas feed, at very high purity as required by the industry. It seems that polymerized ionic liquids showed enhanced CO2 sorption capacities and fast sorption/desorption rates compared with their corresponding ionic liquids

Encryption Efficiency Analysis and Security Evaluation of RC6 Block Cipher for Digital Images

This paper investigates the encryption efficiency of RC6 block cipher application to digital images, providing a new mathematical measure for encryption efficiency, which we will call the encryption quality instead of visual inspection, The encryption quality of RC6 block cipher is investigated among its several design parameters such as word size, number of rounds, and secret key length and the optimal choices for the best values of such design parameters are given. Also, the security analysis of RC6 block cipher for digital images is investigated from strict cryptographic viewpoint. The security estimations of RC6 block cipher for digital images against brute-force, statistical, and differential attacks are explored. Experiments are made to test the security of RC6 block cipher for digital images against all aforementioned types of attacks. Experiments and results verify and prove that RC6 block cipher is highly secure for real-time image encryption from cryptographic viewpoint. Thorough experimental tests are carried out with detailed analysis, demonstrating the high security of RC6 block cipher algorithm. So, RC6 block cipher can be considered to be a real-time secure symmetric encryption for digital images

Investigating cognitive holding power and equity in the flipped classroom

In recent years, the flipped classroom has been proposed as an alternative paradigm of teaching, and has been demonstrated to improve the students' knowledge and skills, engagement, and self-efficacy. At the same time, as the number of students seeking higher education is growing and the needs of these students are rapidly evolving, it has become necessary to improve their cognitive holding power and enhance equity among them. The goal of this study is to investigate the impact of the flipped classroom on improving the students' cognitive holding power and enhancing equity. For this study, the flipped classroom was implemented for teaching undergraduate university students' course "An Introduction to Instructional Technology". In the class, whiteboard and Smartboard were used to discuss and clarify ambiguous ideas related to the topic and to present the model answers for the tasks. Outside the class, video files and Google applications (Word, PPT, Drive) were used for delivering learning materials. WhatsApp was used for communication and Google form was used for designing learning activities and assessment. The results of the study indicate: (1) to some extent flipped classroom can be a solution for improving students' cognitive holding power, especially in performing learning tasks and following teacher' instructions. (2) Equity among the students can be enhanced in the flipped classroom. These findings have implications for using the flipped classroom in managing the diversity of university students through enhancing equity among them and improving their abilitie