Search

Suction anchors are subjected to inclined, quasi-horizontal or quasi-vertical loadings. The type of the structure and depth of water govern the inclination of the load. Under this load condition, suction anchor experiences a combination of horizontal and vertical translations, and rotation. Therefore the soil's reaction to this load condition can be idealized as horizontal and vertical loadings, together with a moment. The magnitude and combination of the reactions depend on the load inclination, soil property and the point at which the load is applied. The behavior of the suction anchor subjected to the combined V–H-M loading is elaborated in this paper. This is to observe the effects of soil properties on the failure mechanism and ultimate capacity of the foundation. This was achieved by applying the pure horizontal and vertical displacements, and rotation and their combinations to the foundation, on V–H, V-M and H-M spaces and the yield-locus created for each space. The general purpose finite element program DIANA was used for this study. Non-linear analysis was conducted using a simplified elastic-perfectly-plastic model with Von-Mises yield criterion for saturated and consolidated clay.

Peninsular Malaysia is located on the southern edge of the Eurasian Plate. However, it is close to a seismically active plate boundary, the inter-plate boundary between the Indo-Australian and Eurasian Plates. Occasionally, tremors can be felt throughout the region even when active faults are located several hundred kilometers away. Lessons learnt from past events, active earthquakes located far from the existing building can cause potential damage. Thus, fragility curves become an essential tool to estimate probability of building damage caused by seismic ground motions. In this study, the response of low-rise and mid-rise RC school buildings located in various soil conditions within Peninsular Malaysia under earthquake excitation was investigated by performing dynamic response spectrum analysis. These buildings were analysed using DIANA 9.3 structural analysis program and subjected to a range of low to high seismic ground motions to determine the performance damage state of each type of building. All structural elements were modeled using solid brick finite-element. Correspondingly, the fragility curves were developed using the log-normal distribution for structural response. The effects of various soil conditions on the response of the buildings were also investigated. The results indicated that the effect of soil parameters had a significant effect on the outcome of the fragility curves. However, the risk of these existing school buildings at a location in the northern part of Peninsular Malaysia showed the highest probability of exceeding each damage state. On the contrary, the risk of the existing school buildings at a location in the central part of Peninsular Malaysia was the lowest. Keywords: Interaction, fragility curves, soil-structure

This paper describes the determination of the location of damage due to single cracks and due to honeycombs in RC beams using mode shape derivatives from modal testing. The cracks were induced by application of point loads at predetermined locations on the RC beams. The load was increased in stages to obtain different crack heights to simulate the extent and severity of damage. Experimental modal analysis was performed on the beams with cracks prior to and after each load cycle, on a control beam, and beams with honeycombs. The mode shapes and the eigenvectors were used to determine the location of damage. The indicator | λ 4 | was obtained by rearranging the equation for free transverse vibration of a uniform beam, and applying the fourth order centered finite-divided difference formula to the regressed mode shape data. The equation is an eigenvalue problem, and the value of | λ 4 | will be a constant. Differences in the values indicate stiffness change, and the affected region indicates the general area of damage. Analysis of results using | λ 4 | was able to indicate the general region of damage, the exact location being around the center of the region. Curve fitting with Chebyshev series rationals onto the mode shape also highlighted points of high residuals around the region of damage. The proposed algorithm on the mode shape can form the basis of a technique for structural health monitoring of damaged reinforced concrete structures.

This preliminary work investigates whether Fourier transform infrared spectroscopy (FT-IR), in combination with multivariate analysis can be used to distinguish Phyllanthus niruri Linn. samples from different locations. A FT-IR spectrometer used in this work is equipped with a transmittance accessory. All samples were scanned in the mid-infrared range of 400–4000 cm −1 but only the region of 400–2000 cm −1 that contained the most spectral information was analyzed with multivariate techniques of principal component analysis (PCA), genetic algorithm (GA), linear discriminant analysis (LDA) and SIMCA. PCA was used to reduce the spectra to three principal components, which explained 96.2% of the whole variance and a plot of principal components two and three showed groupings of the samples according to origin. Secondly, the spectra compressed with PCA were used to develop a LDA. The GA applied for 50 or 100 generations used concept of maximizing the ratio of between-groups variance to within-groups variance and identified the most discriminating variable for subsequent LDA. The SIMCA technique consisted of constructing an enclosure for each location using separate principal component models and using these models to classify the whole data. The best discriminatory approach was the technique using GA with LDA, where using just six wavenumber variables obtained from application of GA for 100 generations, gave 100% correct prediction for both originally grouped and cross-validated data. However, both PCA–LDA and SIMCA also gave very good classification. Basically, FT-IR analysis is rapid and has the power to discriminate samples in terms of geographical origin with the aid of multivariate analyses.

The concept of efficiency can be used for comparing the relative performance of various pozzolans when incorporated into concrete. In this paper, an alternative approach for the evaluation of efficiency factor k of a pozzolanic material has been introduced. The method, developed following Abrams strength-W/C ratio rule, calculates efficiency in terms of relative strength and cementitious materials content. The advantage of this method is that only two mixtures are required to determine the k factor of a specific mixture. A laboratory investigation on silica fume (SF) and metakaolin (MK) concrete found that the computed efficiency factors varied with pozzolan type, replacement level and age. At 28 days, the k values ranged from 1.6 to 2.3 for MK and 2.1 to 3.1 for SF mixtures, while at 180 days, the k values varied from 1.8 to 4.0 for MK and 2.4 to 3.3 for SF mixtures. Generally, the k factors increased with age but declined with higher pozzolanic content. It was also observed that change in W/CM ratio from 0.33 to 0.27 did not significantly affect the resultant efficiency factors. © 2004 Elsevier Ltd. All rights reserved.

A mathematical model is presented for estimating compressive strength of high-strength concrete incorporating pozzolanic materials, based on the strength of a control ordinary Portland cement (OPC) concrete made with similar mixture characteristics and curing history. In this study, metakaolin (MK) and silica fume (SF) were used as cement replacement materials at 5%, 10%, and 15% by mass. Water/cementitious materials (w/cm) ratios varied from 0.27 to 0.33, and strength testing was conducted up to an age of 180 days. It was found that the strength of a pozzolanic mixture could be related to the strength of its equivalent control by a linear function. Key parameters involved in the model are the pozzolanic and dilution factors, which can be correlated to the pozzolan content in the mixture. The study concludes that the accuracy of the model increases with concrete age. At ages 28 days and above, 97% of the estimated strengths are within ±5% of the actual value. © 2004 Elsevier Ltd. All rights reserved.

This paper presents the results of an investigation on the use of metakaolin and silica fume as supplementary cementing materials in enhancing the near surface properties of concrete. Metakaolin and silica fume mixtures, each with 10% replacement, were prepared and tested for initial surface absorption, water absorption and sorptivity. Metakaolin and silica fume were found to enhance the overall near surface characteristics of the concrete. The inclusion of metakaolin and silica fume greatly reduced the initial surface absorption, water absorption and sorptivity of concrete in varying magnitudes. Generally, the curing method adopted had significant effects on the near surface properties of concrete incorporating metakaolin or silica fume.

The weatherability of PTFE- and PVC-coated fabrics under tropical climate was evaluated based on outdoor exposure test for a period of 2 years. This study is confined to the examination of the surface characteristics of 10 different types of fabric which include dirt repellency, discolouration and coating condition. The results indicate that the dirt repellency of PTFE-coated fabrics is generally more superior. However, the surface treatment for some of the PVC-coated fabrics, do provide excellent dirt repellency as well. Morphological examinations using the scanning electron microscope revealed that cracking and peeling of the coating were more evident on the PVC-coated as compared to the PTFE-coated fabrics. The hot and humid conditions prevalent in a tropical environment were very conducive for the growth of fungi, which adhered on the surface of some of the PVC-coated fabrics. Generally the degree of surface degradation on all the fabrics was more severe due to the much harsher tropical climate in comparison with other exposure tests conducted in the past.

Environmental Impact Assessment (EIA) is not mandatory before starting any major road construction or infrastructure development in Brunei Darussalam. Nevertheless, some variations of impact assessment have been conducted as part of the feasibility studies for many of these projects. Such an obligation would encourage most consultants to focus on the merits and problems of the physical state of the environment. Their clients would then be led to examine and adopt the various engineering solutions along with the financial implications as laid out by the consultants. Assessment and preparation for socio-economic changes are often sidelined. Planning for modern transportation cannot afford to ignore the whole spectrum of the environmental impact. The selection of a road or its network is more often influenced by the human landscape and the change in environmental quality than by factors related to landform, earthwork and slope stability. During the construction and operation stages, the impact generally consists of a mixture of positive and negative components. The latter can then be made worse by poor quality in design, construction and maintenance. This paper draws a conceptual approach to the development of good corporate governance for key organisations (clients, consultants, contractors and suppliers) amidst the existing economic landscape and construction practices. All relevant organisations should ideally embrace the concept of an integrated Health, Safety, Environmental and Quality (HSEQ) system to deliver good governance. This structural change will enable all ‘key players’ to deliver solutions that match the benefits derived from traditional forms of EIA and quality assurance (QA). The paper attempts to embed the two obligatory functions, namely the QA and the EIA, into the self-regulatory, responsible, and competitive culture found among clients, consultants, contractors and suppliers in the road industry in Brunei Darussalam.

The rising cost of construction in developing countries like Malaysia has led concrete experts to explore alternative materials such as coconut shells which are renewable and possess high potential to be used as construction material. Coconut shell powder in varying percentages of1%, 3% and 5% was used as filler material in concrete grade 30 and evaluated after a curing period of 7 days and 28days respectively. Compressive strength, water absorption and carbonation tests were conducted to evaluate the strength and durability of CSP concrete in comparison with normal concrete. The test results revealed that 1%, 3% and 5% of CSP concrete achieved a compressive strength of 47.65MPa, 45.6MPa and 40.55% respectively. The rate of water absorption of CSP concrete was recorded as 3.21%, 2.47%, and 2.73% for 1%, 3% and 5% of CSP concrete respectively. Although CSP contained a carbon composition of 47%, the carbonation test showed that CSP no signs of carbon were detected inside the concrete. To conclude, CSP offers great prospects as it demonstrated relatively high durability as a construction material.

Plantar fascia is a ligament found in human foot structure located beneath the skin of human foot that functioning to stabilize longitudinal arch of human foot during standing and normal gait. To perform direct experiment on plantar fascia seems very difficult since the structure located underneath the soft tissue. The aim of this study is to develop a finite element (FE) model of foot with plantar fascia and investigate the effect of the surface hardness on biomechanical response of plantar fascia during running. The plantar fascia model was developed using Solidworks 2015 according to the bone structure of foot model that was obtained from Turbosquid database. Boundary conditions were set out based on the data obtained from experiment of ground reaction force response during running on different surface hardness. The finite element analysis was performed using Ansys 14. The results found that the peak of stress and strain distribution were occur on the insertion of plantar fascia to bone especially on calcaneal area. Plantar fascia became stiffer with increment of Young's modulus value and was able to resist more loads. Strain of plantar fascia was decreased when Young's modulus increased with the same amount of loading.

Gene targeting by homologous recombination at chromosomal endogenous loci has traditionally been considered a low-efficiency process. However, the effectiveness of such so-called genome surgery or genome editing has recently been drastically improved through technical developments, chiefly the use of designer nucleases like zinc-finger nucleases (ZFNs), meganucleases, transcription activator-like effector nucleases (TALENs) and CRISPR/Cas nucleases. These enzymes are custom designed to recognize long target sites and introduce double-strand breaks (DSBs) at specific target loci in the genome, which in turn mediate significant improvements in the frequency of homologous recombination. Here, we describe a Southern blot-based assay that allows detection of gene repair and estimation of repair frequencies in a cell population, useful in cases where the targeted modification itself cannot be detected by restriction digest. This is achieved through detection of a silent restriction site introduced alongside the desired mutation, in our particular example using integration-deficient lentiviral vectors (IDLVs) coding for ZFNs and a suitable DNA repair template.

Biodegradable biphasic calcium phosphate (BCP) scaffold holds tremendous potential for bone tissue engineering. It elicits response from cells such as endothelial cells (ECs) that are similar to those elicited by bone. ECs promote bone regeneration by stimulating both neovascularisation and osteogenesis. For an effective coupling of angiogenesis and osteogenesis, vascular endothelial growth factor (VEGF) is required. The aim of this work is to study the effectiveness of VEGF-added-BCP on the expression of osteogenesis and angiogenesis genes in ECs. Commercially obtained rat aortic ECs were cultured in the endothelial-cell growth medium. The cells were treated with three different modalities: BCP- only, VEGF- only, and VEGF-added-BCP. The optimal BCP and VEGF concentrations were determined. The cells were harvested at four different time intervals (day 3, day 7, day 10 and day 14) and were subjected to RNA isolation using RNA extraction kit (analytikjena, Germany). This was followed by performing reverse transcriptase-PCR (RT-PCR) (Qiagen, Germany) to amplify the osteogenesis and angiogenesis-regulated genes. The RT-PCR products were then electrophoresed. The gel image was captured using Image Analyser. Suitable concentration of BCP was 10mg/ml while optimal VEGF was 15ng/ml. Angiogenesis and osteogenesis genes were clearly expressed in ECs in response to treatments. Angiogenesis gene (VEGF) was highly expressed by VEGFonly treatment but showed some changes with added BCP. Osteogenesis genes (BMP-2, ALP, OC and OPN) were shown to be positively affected by both BCP and VEGF. Some genes were expressed at an earlier time interval compared to the other genes depending on the type of treatments. BCP-only treatment induced high expression of early regulating osteogenesis genes (BMP-2 and OPN). Mineralized gene markers (ALP and OC) were however, highly expressed with VEGF-added-BCP treatment. Combination of BCP and VEGF modality on ECs was suggested to initiate osteogenesis and angiogenesis related gene expressions earlier than the other modalities.

Damage in structures can negatively affect their functionality and safety and leads to failure. Thus it is very important to monitor structures for occurrence, location and severity of damage. Structural health monitoring techniques provide information on the life expectancy of structures simultaneously detects and locates structural damage. Damage identification of structures based on vibration has always been important subjects and are being rapidly used to damage and location of structures. Artificial Neural Networks (ANNs) as a soft computing method using dynamic parameters of structures have been utilized increasingly for structural damage detection due to their excellent pattern recognition capability. Dynamic parameters of structure are easy to implement for damage identification and can directly linked to the topology of structure. This study presents the application of ANN for damage identification in steel beams using dynamic parameters. For identification of severity and location of damage, at first, five individual neural networks corresponding to mode 1 to mode 5 are considered. At the second step, a method based on neural network ensemble is proposed to combine the outcomes of the individual neural networks to a single network. Ensemble results were evaluated and discussed according to the differences between predicted output by ANN and desire data (target data) obtained from experimental modal analysis of structure.

In this study, a new approach for damage detection in beam-like structures is presented. Damage feature such as relative wavelet packet entropy (RWPE) based on the decomposed component is used to identify the damage location and evaluate the damage severity. RWPE describes present information of relative wavelet energies correlated with different frequency ranges. It is should be noted that the acceleration measured in the all three directions should be used in computation of RWPE. Numerical and experimental results are used to verify the practicality of this method. Results show that the damage index technique has great potential in detection of location and depth of cut in a steel beam. The procedure can be applied for health monitoring of other complex structures.

An experimental investigation to study the effect of general corrosion on the modal parameters of reinforced concrete beams was conducted. The full scale beams were subjected to reinforcement corrosion until an appreciable amount of steel corrosion damage was introduced. The states of damage in the test beams were assessed through measurement of crack width and spalling. Modal tests were performed on the test beams after corrosion damage and the modal parameters extracted were compared against that from a control beam. The results obtained showed changes in the modal parameters especially natural frequencies and damping ratio. The trend in the measured natural frequencies was sensitive to the deterioration state of the beams. Changes in modal damping ratio for the transfer function method and the normal mode method were also observed. However, the changes were inconsistent with the changes in natural frequencies, as concluded by previous researchers, but a trend was observed which was rather mode dependent. Furthermore, the load carrying capacity of the beams was determined through static load test and the results were correlated with the state of corrosion damage and changes in the modal parameters. This investigation provides further insight on the use of modal parameters to detect damage in structural concrete elements which can be useful for structural appraisal and assessment purposes when applied to full scale structures.

Wire bond has been an important tool in the world of microelectronic interconnections. The effect of Reactive Ion Etching (RIE) on the successful rate of thermosonic bonding using gold wire on aluminium pad is studied. Surface morphology images from Atomic Force Microscopy (AFM) are used as correlation comparison. In this work wire bonding adhesion is studied on two different surface conditions, which are treated with RIE and the other without RIE treatment. In this experiment only the bonding time was varied for each set of experiments. Results of the wire bond from both samples, with and without RIE were compared. The RIE treated surfaces yield better adhesion results in this work.

The paper proposes a ‘smart basket’ system as an alternative solution to optimize management of electrical and water consumption in domestic laundry activities. The device acts as a microcontroller-based digital weighing system, and weighs unwashed clothes prior to the laundry stage. In principle, the weights are measured through the use of force sensitive resistance (FSR) sensor, where the results are being displayed on liquid crystal display (LCD). The system is designed with a keypad to enable user selection of weights. Buzzer is used to alert users in case where the basket has reached the selected weight threshold. Results using the ‘smart basket’ system were compared with data from Tenaga Nasional Berhad (TNB) and Syarikat Bekalan Air Selangor (SYABAS), indicating that resource consumption can be reduced by as much as 33%.

The adaptive neuro-fuzzy inference system (ANFIS) is a process for mapping from a given input to a single output using the fuzzy logic and neuro-adaptive learning algorithms. Using a given input–output data set, ANFIS constructs a Fuzzy Inference System (FIS) whose fuzzy membership function parameters are adjusted using combination of back propagation algorithm with a least square type of method. The feasibility of ANFIS as strong tool for predicting the severity of damage in a model steel girder bridge is examined in this research. Reduction in the structural stiffness produces changes in the dynamics properties, such as the natural frequencies and mode shapes. In this study, natural frequencies of a structure are applied as effective input parameters to train the ANFIS and the required data are obtained from experimental modal analysis. The performance of ANFIS model was assessed using Mean Square Error (MSE) and coefficient of determination (R2). The ANFIS model could predict the severity of damage with MSE of 0.0049 and correlation coefficient (R2) of 0.9976 for traing data sets. The results show the ability of an adaptive neuro-fuzzy inference system to predict the damage severity of the structure with high accuracy.

Structures are exposed to damage during their service life which can severely affect their safety and functionality. Thus, it is important to monitor structures for the occurrence, location and extent of damage. Artificial neural networks (ANNs) as a numerical technique have been applied increasingly for damage identification with varied success. ANNs are inspired by human biological neurons and have been used to model some specific problems in many areas of engineering and science to achieve reasonable results. ANNs have the ability to learn from examples and then adapt to changing situations when sufficient input-output data are available. This paper presents the application of ANNs for detection of damage in a steel girder bridge using natural frequencies as dynamic parameters. Dynamic parameters are easy to implement for damage assessment and can be directly linked to the topology of structure. In this study, the required data for the ANNs in the form of natural frequencies will be obtained from experimental modal analysis. This paper also highlights the concept of ANNs followed by the detail presentation of the experimental modal analysis for natural frequencies extraction. Key words: Artificial neural networks (ANNs), back propagation (BP), damage identification, natural frequency.

The use of 3D seismic attributes for predicting reservoir properties away from the well bore has been used routinely in the industry. Recently a study utilizing multi attribute analysis and neutral network technique applied to one of the Marrat reservoirs in west Kuwait has not only described the reservoir geometry but has also opened up new areas for exploration. Further, the seismic derived porosity volume has been also integrated with the geological model for future well placement. The Middle Marrat limestone reservoir of Jurassic age in the Dharif field is one of the major oil producers in the area. This field discovered in 1988, is an elongated anticline trending NNE-SSW, with a major fault to the west. The reservoir thickness varies from 50-230ft and porosities ranging from 12 to 20%. Since a Pilot water injection program is being initiated, a good reservoir description would be essential for planning a successful injection program. The seismic derived porosity volume derived from neural network analysis has been a key in identifying inter-well areas as well as regions away from the wells with good porosity which is consistent with the available geological information. Incorporating the porosity volume as a “soft constraint” to the available geological model has further refined the model and is expected to assist in effective placement of future wells.

The main objective of this investigation is to determine the effect of palm diesel on concrete under accelerated laboratory conditions. Mortar samples of ordinary Portland cement (OPC), modified OPC with natural rubber latex, magnesium phosphate cement and epoxy-coated OPC were soaked in palm diesel. Samples were p prepared under different curing regimes and soaked in palm diesel for a definite period. Both visual and microscopic examinations were then made to ascertain the nature of the attack. The change in weight of the specimens was also recorded to quantify the degree of deterioration. The mortar samples containing OPC exhibited the highest degree of deterioration, whilst the epoxy-coated and magnesium phosphate samples were least affected. The degree of deterioration was also dependent on the curing regime. The principal cause of the deterioration was attributed to saponification by the free lime present in the set cement, forming a calcium soap. It can be concluded from the results of this preliminary investigation that surface treatment with epoxy or other suitable materials chemically resistant to palm diesel may inhibit the deterioration on the concrete. Furthermore, by using a different kind of cement that contains a substantially smaller amount of calcium than OPC, the attack of the palm diesel may be reduced or prevented.

Defects were created in the mandible of a rabbit model whereby the right side was implanted with hydroxyapatite (HA) while the left side was left empty to act as control. Both the implant and control sites were evaluated clinically and histologically at 4,12,20,22 weeks. Decalcified sections were studied under confocal laser scanning microscope. No reactive cells were evident microscopically in all sections. There was bone ingrowth as early as 4 weeks when viewed by the topographic method. Enhancement of osteoconduction was evident by the presence of abundant capillaries, perivascular tissue and osteoprogenitor cells of the host. At 22 weeks, the implanted defect showed mature bone formation filling almost the whole field. This study demonstrated that the dense HA exhibits excellent biocompatibility as noted by the complete absence of reactive cells. It also promotes osteoconduction.

Publisher Summary A laboratory investigation to study the effect of general corrosion on the modal parameters of reinforced concrete beams is conducted in this chapter. Full-scale beams are subjected to reinforcement corrosion until an appreciable amount of steel corrosion damage is introduced using an accelerated technique—namely, galvanostatic method. The states of damage in the test beams are assessed through measurement of crack width, loss of area, and half-cell potential. Modal tests are performed on the test beams after corrosion damage and the modal parameters extracted are compared against that from control beams. The results obtained show changes in the modal parameters especially, natural frequencies and mode shapes. The intensity of the drop in the measured natural frequencies is sensitive to the deterioration state of the beams. Changes in natural frequencies could be established as a damage indicator, which relates to the loss in flexural stiffness of the corroded beams. Using modal assurance techniques to perform orthogonality checks on sets of mode shape from the control and corroded beams, changes can be visualized, which are dependent on the degree of corrosion damage induced. Finally, the load carrying capacity of the beams is determined through static load test and the results are correlated with the state of corrosion damage and changes in the modal parameters. This investigation provides further insights into the use of modal parameters to detect and assess damage in structural concrete elements.

High strength concrete mixtures containing 10% metakaolin replacement and 10% metakaolin addition, water/cementitious material ratio of 0.3 and 1% superplasticizer were studied. Similar mixtures incorporating silica fume were also prepared. The effect of mineral admixtures on the fresh and hardened properties of concrete was investigated. Mixtures with mineral admixture exhibited lower workability, less bleeding, and slightly lower air content. Metakaolin resulted in a higher loss of workability compared with silica fume. Mixtures incorporating mineral admixture developed greater compressive strength and elastic modulus at all ages. The enhancement was more pronounced at early ages and in the addition mixtures. The study concludes that the performance of metakaolin is equivalent to silica fume in terms of contribution to the enhancement of strength and elastic modulus. The metakaolin addition mixture attained 70% and 50% strength improvement while the metakaolin replacement mixture achieved 67% and 39% strength increment at the respective ages of 3 and 28 days.

SUMMARYFive field experiments studied the effects of high planting densities, ranging from 83,000 to 667,000 seeds/ha, on eleven soyabean cultivars. Germination rates ranging from 32 to 100% and averaging 76%, resulted in actual plant densities of 45,000 to 296,000 plants/ha. Bean yields of the four shortest and earliest-maturing (64–67 days) cvs (Wakashima, Shi-shi, Palmetto and Tai Tah Kaoh Siang 58) increased with increasing density, producing highest yields at the highest plant densities investigated (222,000–286,000/ha) but 7 taller cvs, maturing in 80–126 days (P2, C13, C21, P4, D5, T10 and C28), produced reduced yields with increasing density, the lowest densities investigated (45,000–83,000 plants/ha) giving the highest bean yields.