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The inherent vulnerability of beam-column joints to seismic loading and steel congestion are two major research problems connected with beam-column joints of moment-resisting frames. The experimental study presented herein addresses these research questions and seeks to solve them by using Polyvinyl Alcohol based Engineered Cementitious Composite (PVA-ECC) in beam-column joints without transverse shear reinforcement. The study included the manufacture and shake table testing of two 1:3 reduced scale one bay two-story moment-resisting frame models using simulated earthquake motions. To evaluate the performance of ECC beam-column joints without shear reinforcement, two frame models, one with and the other without shear reinforcement in the beam-column joints, were prepared and tested. The acceleration time history record of the 1994 Northridge Earthquake USA was used for the excitation of specimens at different levels to produce progressive damage up to the near collapse state. The observed damage mechanism of tested models was recorded, and the response parameters, including floor displacement and acceleration, were measured. The measured data was processed to develop a lateral force-displacement envelope curve for the supposed prototype frames and calculate their seismic design factors (ductility, overstrength, and response modification). Comparison of the seismic performance parameters of the two prototype frames reveal that the ECC beam/column joint without shear ties performed marginally inferior to the ECC beam-column joints having shear ties but it still achieved a 75% larger R-factor compared with the code specified value.

This paper presents an experimental study on the flexural behavior of composite Reinforced Concrete (RC) beams having a monolithic Engineered Cementitious Composites (ECC) layer at the tension face. Due to the brittle nature of normal concrete, clear cover on the tension side of beam cracks results in spalling and corrosion of reinforcement. The proposed technique overcomes the inherent brittle behavior of normal concrete with the incorporation of ECC on the tension face. This also helps in reducing bond-splitting, cover-spalling, and buckling of reinforcement in RC flexural members. For testing purposes, six full-scale beam specimens (225 mm x 300 mm x 2400 mm) with the same reinforcement were cast and tested. Out of six, two specimens were made of conventional concrete, whereas the remaining four (two each) had an ECC layer of 75mm and 100mm thick at the tension face respectively. Each specimen was installed with three strain gauges (one each at the midspan top & bottom surface of concrete and one midspan rebar on the tension face) and one LVDT at midspan. The samples were then subjected to simple monotonic loading under a third-point bending test as per ASTM C78. The load-displacement, stress-strain and moment-curvature curves were obtained for all the tested specimens. It was found that ECC-strengthened beam samples displayed an increased flexural performance at first crack, yield, and ultimate load-carrying capacity as compared to conventional RC specimens. Whereas a better crack arrest with even distribution of cracks and improvement in ductility was observed for the ECC-strengthened composite beams.

This paper presents the first-of-its-kind shake table testing and detailed investigation, carried out on one-third reduced-scale Engineered Cementitious Composite-Reinforced Concrete (ECC-RC) hybrid moment-resisting frame structures. The experimental models included a code-compliant model conforming to the seismic building codes and a non-compliant model. The non-compliant model incorporated the deviation of construction practices from the design by using low strength concrete, lacking ties in joints, practicing of 90° hooks, reduction in longitudinal reinforcement ratio, and larger spacing of ties. For structural seismic performance evaluation, the natural acceleration time history of the 1994 Northridge was linearly scaled and applied unidirectionally to both the models through a Shake Table. Seismic response curves were developed by correlating roof displacement demand with the peak sustained acceleration of base motions. The structural natural frequencies and damping ratios were calculated based on free vibration tests. The structural overstrength, displacement ductility ratio, and response modification factor R were also computed. The experimental models with ECC-RC beam-column connections demonstrated the capability to sustain significant lateral displacements at roof-level without jeopardizing the global stability of the structures. The seismic behavior of ECC-RC structural systems shows good promise for potential use in situations where quality assurance on construction sites is not ensured.

This paper presents the outcome of a research study aimed at the performance evaluation of rice husk ash as partial replacement of cement in sandcrete blocks used as masonry units. Rice husk from rice cultivated in the North of Pakistan was used in the study. It was first combusted in a locally manufactured incinerator to convert it into rice husk ash (RHA) and then finely ground to powder form for use with cement. Blocks of size 305 mm×203 mm×152 mm were molded with 0, 10, 30, 40 and 50 % replacement of cement with RHA to find compressive strength at 3, 7, 14 and 28 days age of curing. The results showed that water requirement for the required workability of the sandcrete increased with increase in RHA content whereas compressive strength decreased with increase in RHA content. However, the comparison of compressive strengths of RHA sandcrete blocks with the strength of commercial concrete blocks available in the market and used as masonry units in Pakistan showed that sandcrete blocks having sand to binder ratio of 1:8 and using up to 40% of RHA as replacement of cement gave larger compressive strength than that of commercial concrete blocks and only marginally lower strength for 50% replacement.

The production of conventional engineered cementitious composites – ECC consumes low-volume and expensive ultrafine silica sand [UFSS] – maximum size 250 μm, which negatively affecting dry shrinkage, cost and practical application of ECC. This study develops an economical ECC featuring ordinary quarry sand [QS] with a lower fineness modulus – FM = 2.2 and a maximum particle size of 2350 μm. The quarry sand particle size was ten times greater, and the price was 30 times lower than UFSS. The experimental finding was shown that ECC prepared with QS exhibited the strain hardening phenomenon, with multiple cracks produced, before failure. The performance of QS was also checked under different temperature regimes, and a minor decrease in the mass density and compressive strength was observed, up to 200°C. After 200°C, a significant decrease in compressive strength was found, due to the melting of the PVA fibers.

An experimental work has been carried out to study the flexural behavior of cast in-situ hollow core reinforced concrete (HCRC) slabs constructed by using easy, cost effective and implementable techniques in field. The precast elements made of different easily available affordable material i.e. concrete, polyvinyl chloride (PVC) and plaster of paris having voided cross- sections of circular, rectangular and triangular shapes were incorporated in one direction during pouring of concrete with minimum flexural reinforcement to construct HCRC slabs. A total of 14 slab specimens including 02 specimens per specification were tested with third point loading for the assessment of flexural behavior as per ASTM standards C78/C78M. The flexural behavior of HCRC slabs with polyvinyl and plaster of paris elements having hollow cross-sections was comparable with the control solid slabs, however, HCRC slab with concrete pipes showed 7 to 8 percent reduction in flexural strength with 19 to 20 percent reduction in self-weight. All the tested specimens performed well in shear as no shear failure was observed. This study reveals that HCRC slabs with locally available material having hollow cross section elements can be used for the construction of cast in-situ monolithic construction of one-way slabs with ordinary construction techniques. Doi: 10.28991/cej-2020-03091597 Full Text: PDF

This study presents experimental investigation of indigenous clays mixed with Bentonite to assess their suitability in potential use as clay liners. Soil samples with 0, 4, 8, and 12% Bentonite content from three different sites in Peshawar region were tested for various geotechnical properties. Grain size distribution, specific gravity, Atterberg limits and free swell were found through laboratory tests using appropriate ASTM procedures. Maximum dry density and optimum moisture content were calculated using Atterberg limits in available relationships. Finally, one dimensional consolidation tests were conducted to find relevant parameters for calculating hydraulic conductivity. A decrease in specific gravity, increase in free swell, and in optimum moisture content, decline in maximum dry density and hydraulic conductivity was observed with increase in Bentonite content across all three soil samples. During free swell, the soil clusters become larger leading to formation of floccules resulting in the narrowing of inter-particle space and thus blocking of permeable paths. It is concluded that 8% Bentonite content by weight yields a suitable mixture for a clay liner that has hydraulic conductivity in the range of recommended limits.

Strengthening of structural members is a common practice around the world that may arise due to deterioration of concrete with age or upgradation of design code. This paper aims to elucidate a technique used for strengthening of the reinforced concrete beam for flexural capacity by using externally welded steel angles and steel bars. For this motive, three beams were strengthened with external steel angles and three with external steel bars. The external strengthening steel elements were attached at the bottom of the beam with shear reinforcement. Control samples without external steel angles and steel bars for comparison purposes were also prepared. All reinforced concrete beams were first constructed using a concrete ratio of 1:2:4, and then external steel elements were added to existing flexural reinforcement by using a fillet weld with tee joints having thickness and length of 5/16" (7.9 mm) and 6" (152.4 mm), respectively. Fourth point loading criteria were used to investigate the flexural capacity of beams in positive bending. All beams were designed strong enough in shear, to resist the ultimate loads without shear failure. Test results indicated that beams strengthened with this technique have an average increase of 238% with steel angles and 106% with steel bars, in load-carrying capacity than control samples. Strengthened beams showed a uniform crack pattern. Moreover, the concrete cover made a good bond with existing concrete and was strong enough to withstand ultimate loads. Conclusively, the steel angles and steel bars can be used as an external strengthening material, to enhance the flexural capacity of reinforced concrete beams.

This research work aims to compare the seismic performance (in terms of lateral load strength, stiffness, ductility, response modification factor and performance levels) of full scale infilled frames before and after retrofitting. To evaluate the seismic performance, two infilled frames with door opening at different locations were constructed in the laboratory based on the current construction practices in Pakistan. In one infilled frame, door opening was at the center (Frame-1) while in other, door opening was at a side (Frame-2). After construction, both the specimens were tested with quasi-static test. The damaged parent specimens were then retrofitted with Ferrocement overlay and cracks in the infill wall were repaired with grout injection. Steel door frames of gauge 18 were installed at the door opening to make the model more realistic. Results obtained after performing quasi static test on the retrofitted specimen have showed that the specimens not only gained the original strength, but the seismic parameters of the infilled frames were observed to have also improved.

A concise critique on harnessing the abundant solar thermal energy and improvement with vacuum insulation for the utilization and conversion is presented. This research implicates that the world is becoming a global solar smart city prompted by increasing daily demand of energy by the global population and land-use. Amongst all the renewable energy resources available, solar thermal energy collectors (STC) are the most copious because it is accessible in both direct and indirect modes with global solar thermal capacity in operation in 2019 was 479 GWth and annual energy yield estimated to be 389 TWh. Hybridization has been found to be the only way of improving the existing performance of (STC) such as hybrid photovoltaic thermal (PVT) with phase-change material (PCM) for energy storage and magneto-thermoelectric generators (MTEGs) and/or vacuum insulated TEG (VTEG) for waste heat energy conversion to electrical power. The concentrating solar power (CSP) technologies were also precisely studied and yet parabolic trough collector, dish sterling and solar tower are amongst the top solar thermal heat energy harvesters and its electrical power generation has also been comprehended. The modern eminence of vacuum insulation technologies on thermal comfort and sound insulation in sustainable low-carbon buildings is presented. The research implicates that there is still a scope of improving the building and construction sector and target to achieve not only zero-energy buildings (ZEB) but generating-energy buildings (GEB). A concise critique on vacuum insulated smart glazed windows is presented and the review implicates that the hybridization with PV and TEG and novelty in the constructional materials of vacuum glazing (VG) and translucent vacuum insulation panel (TVIP) are vital in the realistic move towards the GEB. The future of vacuum insulation is not only limited to GEB but vital applications occur in medical, imaging, mechatronics and manufacturing industries.

In the marble industry, a lot of marble is wasted in the form of odd blocks of various sizes and slurry consisting of water and micro-fine particles. The slurry on drying converts into powder. Both slurry and powder have adverse effects on the environment. This research is focused on the gainful utilization of waste marble powder (WMP) by converting it into a valuable binding material. For this purpose, WMP and clay were collected, and their physical and chemical properties were determined. A mix of WMP and clay was prepared and burnt at a temperature around 1300 oC. The burnt mix was ground to powder form to get marble cement (MC). The MC was then used in mortar. The compressive and flexural strengths of mortar cubes and prisms were determined. Apart from this, X-ray diffraction (XRD) analysis, thermo-gravimetric analysis (TGA) and scanning electron microscopic (SEM) analysis were also carried out. The chemical composition showed that the MC has 52.5% di-calcium silicate (C2S) and 3.5% tri-calcium silicate (C3S).The compressive strength of MC mortar after 28 days curing is 6.03 MPa, which is higher than M1 mortar of building code of Pakistan (5 MPa). The compressive strength of MC mortar after one year is 20.67 MPa, which is only 17% less than OPC mortar.

This study focuses on the efficient utilization of engineered cementitious composite (ECC) in reinforced concrete (RC) frame structures. In this regard, ECC has been incorporated in the joint panel and plastic hinge zones of the connecting frame elements. For the evaluation of dynamic performance assessment of such hybrid ECC-RC frame structure, a two-story (low rise) RC-frame structure was selected. Two different structural detailing configurations were considered, a model confirming modern seismic code requirements (Code-Compliant Models), while the other was detailed with some seismic code deficiencies (Non-Compliant Models). For experimental testing, 1:3 reduced scale representative models were fabricated. These models were subjected to a 1994 Northridge accelerogram record through a unidirectional shake table. The damage observed in the conventional RC model has exhibited diagonal cracking at the joint panel and concrete crushing. In contrast, ECC-RC models demonstrated minor column damages without severe cracking of the joint core. For dynamic response evaluation, the seismic response parameters (yield stiffness, yield strength, ductility, overstrength factor, and R-factor) for all the models were computed and compared to evaluate the possibility of incorporating ECC at crucial locations. For the ECC enhanced code-compliant and non-compliant models, the response modification factor increased by 37.62% and 16.61%, respectively, compared to the RC countermodels. In addition, the peak input acceleration was correlated with the peak roof displacement to obtain the seismic response envelopes. The performance of ECC-RC models was exceptional for the non-compliant models, which enhance the seismic ductility and energy dissipation for highly optimized frame structures. Hence, it is believed that the efficient use of ECC in critical regions of frame structures can be vital in mitigating the seismic risk.

Advancement in the construction industry causes decline in the availability of natural resources, and this decline can be overcome by utilization of the available raw materials. This study is focused on the combined effects of ethylene vinyl acetate (EVA) and ladle furnace slag (LFS) on fresh and hardened characteristics of self-compacting concrete (SCC) by replacing some fraction of cement and sand. The characteristics of SCC in its fresh state are investigated by workability, while hardened characteristics are investigated by elastic modulus and compressive, tensile, and flexural strength. The findings showed that the workability is enhanced by the incorporation of EVA, while decreased with LFS. Furthermore, all the strength properties were enhanced at all the replacement levels of EVA and LFS except for the splitting tensile strength. The utmost gain in elastic modulus and compressive, tensile, and flexural strength was up to 18, 20, 10, and 15% more by increasing the dosage of LFS while keeping EVA constant.

Nanomaterial is a new kind of heat transport medium, comprising nanoparticles (1–100 nm) which are homogeneously and stably dispersed in continuous phase liquid. These dispersed nanoparticles, generally a metal or metal oxide significantly improve the thermal performance of the nanomaterial, enhances convection and conduction coefficients, allowing for more heat transport. The current communication models the flow of Jeffrey nanomaterial subject to variable thicked surface. The surface is convectively heated. Joule heating, convective boundary conditions and nonlinear radiative heat flux are taken into account. Equal strengths of diffusion coefficients are considered for homogeneous and heterogeneous reactions. Boundary layer concept leads to mathematical modeling. Suitable transformations are implemented to convert the nonlinear systems to ordinary ones. Series solutions are achieved through the HAM technique. Physical importance of emerging parameters is addressed through graphical sketch. We explored that temperature is increased for higher values of radiative heat flux and Eckert number.

Here, cubic autocatalysis in radiative flow of power law fluid is addressed. Flow is examined by a stretched surface. Heat generation/absorption, nonlinear radiation and dissipation effect are utilized in modeling of energy equation. Through implementation of second thermodynamics law, the entropy rate is calculated. Further entropy generation is explored with respect to homogeneous and heterogeneous mass concentrations. Nonlinear system is tackled via NDSolve of MATHEMATICA. Impacts of pertinent variables associated with flow are physically discussed for the velocity, entropy generation, temperature and concentration fields. Clearly, entropy augmentation rate is controlled through Brinkman number. Main key points are presented.

Deformable oil drops of two interfacial tensions (namely, 4 and 30 mN m−1) were filtered through a slotted-pore membrane (with pore dimensions of 4 × 400 μm) at four vibrational shear rates (namely, 0, 1200, 3200 and 8000 s−1) and two permeate fluxes (namely, 200 and 1000 l m−2 h−1). The membrane material was made of nickel. The membrane surface was modified with Poly tetra fluoroethylene (PTFE)F for better performance in-terms of higher flux rate rejection. The oil with the lower interfacial tension was more deformable, because the increase in TMP was less due to the passage of even larger drops to the slot opening, also the permeate quality was lower as a result of the higher concentration of the oil in the permeate. The impact of interfacial tension was more significant under the following conditions; first at lower shear rates, the particle back-transport effects become more dominant than the deformability effects at higher shear rates, and secondly at the higher permeate flux, the higher permeate drag enhances the deformability effects. Discrepancies were observed between experimental results and model predictions based on circular membrane pores and non-deformable foulants. In the future, it is expected that a better agreement of the experimental results and the analytical model could be obtained if the model is modified for the slotted pore membrane.

The response of a helical strand is difficult to model theoretically, as it involves lengthy mathematical formulations. It is highly desired by the practicing engineers to have a simple and reliable method for the prediction of bending stiffness of multi-layered strands. A method for the estimation of bending stiffness of large diameter multi-layered strands has been proposed in this paper. The development of this method was carried out using significantly large number of parametric studies on a variety of strand construction which were also validated using the experimental data. The proposed method is simple in nature for direct engineering applications which provides an effective tool for calculating effective bending stiffness of a strand subjected to any bending curvature.

The increase in the concrete demand due to the rapid industrialization and urbanization may lead to a shortage of natural resources. Therefore, the use of recycled material in the batching of concrete will be helpful to meet the demands of the time without compromising the quality of concrete production. One such waste material produced in Pakistan is waste marble powder (WMP) that is generated from the marble factories during cutting of the marble stones, which in turn have a damaging effect on the environment. This study is based on the utilization of WMP as a partial substitute of the sand in concrete production and its various effect on the mechanical properties of the concrete. Different types of tests (unit weight, workability, compressive strength, splitting tensile strength, and water penetration) were carried out at 0–80%, of sand replaced with WMP, at increments of 20%. In all mixes, the ratio of water to cement was kept constant and the effects of curing conditions were studied at 14, 28, and 70 days. It was observed that with the incorporation of WMP, the workability and unit weight of concrete decrease proportionally to replacement percentage, whereas mechanical properties of concrete increase up to a certain percentage and then decrease. The maximum improvement in compressive strength was achieved at a 40% replacement, with a slight improvement in the tensile strength at 20% replacement. The water penetration test revealed a decrease in permeability with the increase in WMP percentage. Based on the results, it was recommended to use WMP up to 40% in the concrete mix as a replacement of sand.

Here peristalsis of Carbon nanotubes is performed between non-uniform propagating waves channel/tube. Viscosity of the material is considered dependent upon temperature here. Thermally radiative aspects are considered through linear term of heat flux. Channel boundaries retain the momentum and thermal slip characteristics. Iijima suggested physical quantities for single and multiple WCNTS are taken. Conservation principles (i.e. Mass, momentum and energy) are used to modeled the flow. Later on lubrication assumptions are utilized to simplified such equations. Exact solution for stream function, velocity and temperature is carried out. Further pressure rise per wavelength is plotted via numerical integration. Effective heat transfer rate is analyzed through bar charts.

The rice husk (RH) as an agro-waste materials having low nutritional properties as a provender, when burnt under controlled temperature produce great quantity of Rice Husk Ash (RHA). The use of RHA as a supplementary cementitious materials have much importance in construction industry especially in the countries of high rice production. This paper discus the collection of rice husk (RH) from different regions of Khyber Pakhtunkhwa (KPK), the properties of Rice Husk Ash produced from these RH by different combustion methods of high temperature and their effect on mechanical behavior of cement. To evaluate the chemical composition and quantification of crystalline silica in RHA of various regions of KP, EDX and XRD tests were performed. Consistency, setting time, compressive, flexural strength and Alkali silica reaction tests were also performed for various replacement level of RHA i.e. 5%, 15% and 25% in cement paste and in mortar. Results show an obvious variation in the silica content with variation in sources. A partial transformation of amorphous silica to crystalline silica was observed at 800 °C (method A) and mostly at a temperature of 1000 °C (method B). RHA by method A and B, as a partial replacement of cement increase linearly the consistency and setting time but decrease the alkali silica reaction. Also the RHA by method A increased the compressive and flexural strength up-to 15% at later ages but a slight increase was observed up-to 5% replacement of RHA by method B.

To improve the essential properties of soil, stabilization proved to be more significant in overcoming the limitations of the desired soil. The improvement of soil properties will not only enhance the mechanical properties rather it will help in preventing dust and erosion formation. In this study, a set of tests are carried out to examine the strength characteristics of subgrade soil blended with ethylene vinyl acetate (EVA) and cement. EVA contributes almost 14% mass to the global waste, requiring bigger lands for its disposal; therefore, in order to promote a green environment and to bring an economical waste management system, an investigation of using EVA in the soil stabilization techniques is attempted. Soil specimens are investigated with and without the inclusion of EVA and cement. For this purpose, EVA was mixed with soil at a percentage level of 3, 6, and 9% whereas the cement was mixed at a percentage level of 4, 6, and 8%. To examine the combined effects of EVA and cement, the specimens were tested for compaction, direct shear, unconfined compression, triaxial, XRD, porosity, and permeability tests. All the soil samples were cured at 7, 14, and 28 days followed by the standard testing procedure. When cement was added to soil up to 4, 6, and 8% at a constant level of EVA (9%), cohesion was increased by 37, 42, and 46% while the unconfined compressive strength (UCS) was increased by 76, 81, and 84% for the same mixes. From the statistics, it clearly evident that the percentage increase caused by the addition of even 3% EVA to the cemented and uncemented soil specimens is very significant regarding cohesion and compressive strength. Porosity and permeability of soil containing both EVA (9%) and cement (8%) were decreased by 37% and 77%, respectively.

An extremely high tool wear rate in the machining of titanium alloys (Ti alloys) is one of the major reasons limiting the use of conventional machining processes for the components made of these alloys. The machinability of a -Ti-15V-3Al-3Cr-3Sn (Ti- 15333) alloy can be signi cantly improved using an advanced machining technique known as Ultrasonically Assisted Turning (UAT). The key mechanism of tool wear associated with UAT of Ti-15333 alloy is still unknown. The present study begins to address this issue by examining wear behaviour of two di erent types of cutting inserts using UAT and Conventional Turning (CT) of Ti-15333 alloy. Tool wear was measured using 3D optical microscope and the composition of the Built-Up Edge (BUE) on the worn tools was analysed with scanning electron microscopy. A robust experimental methodology was developed, which provided repeatable and statistically reliable tool wear results. The KC5510 cutting inserts demonstrated better tool-life in UAT when compared to CP-500 inserts.

The Sheehan Irritability Scale (SIS) measures the frequency, severity, and impairment associated with irritability in psychiatric patients. The content validity of the SIS in patients with major depressive disorder (MDD) has not been evaluated. A cross-sectional, qualitative research study was conducted to assess the content validity of the SIS among patients with MDD. One-on-one interviews were conducted, starting with open-ended questions to evaluate the consistency of the SIS content with patient experiences of irritability. Participants then completed the SIS and cognitive interviews around the comprehension of the SIS content (instructions, items, response options). Participants included 24 patients diagnosed with MDD who had an inadequate response to an antidepressant treatment. The sample was: 50.4 mean years, 66.7% female, and 91.7% white racial background. All concepts on the SIS were spontaneously mentioned by at least one participant, and when probed about the symptoms, the majority of participants (66.7-100%) reported the concepts being part of their experience. The majority of participants (70.8-100%) understood the SIS instructions, items, and response scales. This study provides evidence of content validity of the SIS in patients diagnosed with MDD, supporting the use as a measure of irritability in patients with depression.

A new method of purification of produced water is reviewed. Recently membrane oscillation for separating solid particles and liquids drops has attracted researchers globally. Metallic slotted pore membranes were used in the experiments. Membrane oscillation generates a shear rate that drives particles, oil drops away from the membrane surface and, hence, fouling is reduced. It is shown that reduction of the fouling is directly related to the intensity of the membrane oscillation. It is shown that membrane oscillation results in decreasing pore blocking and it was found that pore blocking was also reduced with increase of the membrane oscillation frequency. The latter conclusion was confirmed both experimentally and theoretically. The applied shear rate has a strong influence on the larger particles as compared to the smaller ones and therefore, cut-off of separating particles increases with the membrane oscillation. The method was suggested to predict concentration of particles in the permeate. The experiments reviewed were mainly on separation of drops of both vegetable oil and crude oil from aqueous produced water.

This paper presents a new analytical formulation to predict the bending stiffness of multilayered spiral strands. The effect of interwire contact forces and slip between wires have been ful...

Removal of crude oil droplets from produced water has been evaluated using a Nickel membrane with a slotted pore width of 4 μm and length of 400 μm. The membrane was oscillated at different frequencies that resulted in variable intensity shears at the membrane surface. The influence of membrane oscillations on oil droplet rejection was investigated and reported in this work. Membrane oscillations generated a lift for the surrounding particles which led the drops to move away from the membrane surface. Measurements have shown that the intensity of the droplet lift was linearly proportional to the intensity of the applied shear. Inertial lift velocity model reported in literature was used as a starting point which was coupled with the fluid’s convection velocity. The model predicted 100% cut-off points through the membrane at various oscillation frequencies. Without the applied shear rate, the static and drag forces balanced each other, which was assumed to be the 100% cut-off point. With the applied shear rate, the inertial lift and convection velocities become equal and this point was referred to as 100% cut-off point. Overall mass of crude oil droplets in permeate flow was calculated knowing the 100% cut-off point and interfacial tension between the dispersed and continuous phases.

Brick masonry is widely used for building construction throughout the world. However, unreinforced brick masonry buildings performed poorly in the 2005 Kashmir earthquake, in Pakistan, resulting in a decline in the use of brick masonry. In order to investigate and quantify the performance of brick masonry against the seismic forces by confining it through typical stiffer, line elements (column and beams), a full-scaled room model of an area 3048 × 3658 mm (10 × 12 ft) and height of 3353 mm (11 ft) was constructed using confined brick masonry. The model was tested under quasistatic loading system. Crack pattern was noted at the end of each loading cycle. The response of the model was interpreted through a hysteresis curve, which was then idealized by a bilinear curve. A comparison of the results has been made with four different studies done on the similar model made of unreinforced brick masonry before and after retrofitting and unreinforced concrete block masonry before and after retrofitting previously tested at the same testing facility.

The empirical and numerical design approaches are considered very important in the viable and efficient design of support systems, stability analysis for tunnel, and underground excavations. In the present research work, the rock mass rating (RMR) and tunneling quality index (Q-system) were used as empirical methods for characterization of rock mass based on real-time geological and site geotechnical data and physical and strength properties of rock samples collected from the alignment of tunnel. The rock mass along the tunnel axis was classified into three geotechnical units (GU-1, GU-2, and GU-3). The support systems for each geotechnical unit were designed. The 2D elastoplastic finite-element method (FEM) was used for the analysis of rock mass behavior, in situ and redistribution stresses, plastic thickness around the tunnel, and performance of the design supports for the selection of optimum support system among RMR and Q supports for each geotechnical unit of tunnel. Based on results, Q support systems were found more effective for GU-1 and GU-2 as compared to RMR support systems and RMR support systems for GU-3 as compared to Q support systems.

Size distribution of crude oil drops in the permeate has been predicted using the ‘linear fit’ approach with, and without oscillating the membrane. Without membrane oscillation (without shear rate), static and drag forces are taken into account and their balance is assumed as 100% cut-off or rejection point. With the membrane oscillation, ‘inertial lift’ model available in the literature is considered and in this case 100% cut-off is assumed when away migration and convection velocities becomes equal. Three types of crude oil drops with different °API values and interfacial tensions are analysed experimentally, the results are compared with the presented model and the model is an agreement with the experiments. The study has been validated with the genuine size distribution of oil drops obtained from oil companies operating at Kuwait at various locations in order to investigate the industrial applicability of the model. Overall oil concentration of the permeate can be calculated using the proposed model that provides an idea whether the concentration of oil in the permeate is within the standard set by international regulatory authorities.

The model presented in the paper is the continuation of the previous work where a mathematical model was developed for the passage and deformation of micro-sized oil drops through a 4 μm converging slotted pore membrane. In the previous work, it was assumed that drops deform from a spherical shape to a prolate spheroid when pass through a converging slot. In the present study, it has been assumed that drops deform into an oblate spheroid while passing through a non-converging slot and a mathematical model is developed for the deformation of drops through non-converging slots. After extending the idea of static and drag forces, it is readily seen that the magnitude of static force ( F cx ) for the non-converging slotted pore membrane is higher than the static force ( F cx ∗ ) for the converging slotted pore membranes. This is because of drops deform suddenly in the non-converging slots, while, in case of converging slots, the drops deform gradually. Micro-sized oil drops of two systems with different interfacial tensions (4 and 9 mN/m) have been used in the study and it is observed that a higher interfacial tension leads to a higher rejection rate for both converging and non-converging slotted pore membranes at various in-pore filtration velocities.

In previous work, certain shortcomings of traditional design approaches against restrained bending fatigue of axially preloaded spiral strands used in cable stayed structures (e.g. bridges) based on the extreme fibre direct stresses have been identified and subsequently resolved. Restrained bending fatigue life of such spiral strands clamped at the end(s), is shown to be governed by interlayer fretting fatigue. Interlayer fretting is found to be greatest near the so-called neutral axis and not the extreme fibre position, where, during tests, initial wire failures have invariably been found to occur. A new parameter has thus been developed for design against such rather common and often very costly fatigue failures. The reliability of any restrained bending design procedure is based on a reasonably accurate estimation of the minimum critical radii of curvature at the fixed end(s) with such values of curvature then used as an input into the fatigue design model. The present paper makes significant progress in resolving the longstanding debate in the literature as to whether the traditional method of assuming a constant effective bending stiffness for estimating such critical curvature(s) is a practically reasonable one.

Plants are crucial components of eco and agrosystems & are the first compartment of the telluric food chain. When grown-up on contaminated soils, they become latent threat to human and animal fitness as they may gather some toxic elements (e.g., metals) in their tissues and causing many serious problems. A new preliminary draft report by “ArizonaSkyWatch” shows dramatic increases in heavy metals that simply do not belong in our air. These figures indicate how many times they are over the allowable toxic limit: Cd 6.0, Cr 6.4 & Zn 7.5. The current study was aimed to evaluate chromium, zinc and cadmium in the leaves of Salix nigra using atomic absorption spectrometry (UV-750 Spectrophotometer). The results showed higher concentration of chromium in S. nigra (0.079 mg/Kg). Zinc and cadmium were with values of 0.55 and 0.04 mg/kg. The chromium levels in the leaves of S. nigra falls above the acceptable limits whereas zinc content exceeds the FAO/WHO set limits which are (99.4 and 0.20 mg/kg). The sturdy connection between the degree of contamination and concentrations in all plant leaves displayed the results that the leaves of S. nigra imitate the environmental changes accurately, and that they seem as an effective biomonitor of environmental quality in areas subjected to industrial and traffic pollutions.