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The production of coal ash waste is rising alongside the need for power. Therefore, it is necessary to reuse coal ash waste. However, it is unclear if coal ash is genuinely safe for the environment. In this study, coal ash waste and treated marine clay will be subjected to toxicity characteristic leaching to determine the ground contamination caused by coal ash, cement, and marine clay stabilisation. Using the US Department of Environmental (DoE) standard, all three samples of bottom ash, fly ash and treated marine clay (15% 50BA:50FA) showed values below DoE regulatory limits, with the treated sample having the lowest. Using the Malaysian Water Standard, it was determined that the quantities of Cd, Se, and Ag in all three samples were within the regulatory limits established by the Malaysian Water Standard. Except for Cr and Hg, the concentrations of elements identified in the treated 15% 50BA:50FA sample were all within regulatory limits. In descending order, the trend of heavy metal leaching was Ba > Hg > Cr > As > Pb > Ag > Cd > Se, with Ba leaching the most. According to the U.S. Department of Environmental Protection, coal ash and stabilised marine clay are deemed environmentally safe (DoE). For the Malaysian Water Standard, however, water leached from treated marine clays could not be consumed directly. It must be processed before being supplied to consumers.

Purpose This study aims to propose another alternative numerical modelling tool, i.e. ABAQUS, to simulate a fully coupled seepage-deformation analysis in unsaturated slope subjected to rainfall infiltration. Design/methodology/approach The effect of rainfall infiltration on the response of pore water pressure and factor of safety has been analysed and discussed. The results of this study have also been validated based on the results of field monitoring and previous numerical modelling. Findings The results from ABAQUS show a better agreement with those from field monitoring compared to other numerical modelling tools. Originality/value The procedures adopted in this study can be adopted and used as a guide to model similar slope problems in ABAQUS.

Tunnel lining design is an interactive problem, which is not merely about the strength, but on how much the tunnel allows to flexure to overcome the ground movement. When tunnel interacts with soil, stress from the ground is distributed into the structure. In the case of precast segmental bolted tunnel lining, it is critical to investigate the lining joint reaction, as this affects the overall flexural behaviour of the tunnel lining. Understanding the segmental behaviour is important to optimize the design of lining, leading to cost effective production and maintaining the good services during its design life. The objective of this paper is to present a short review on research works conducted in the past pertaining on the joint effect in longitudinal seam in tunnel lining. Review on numerical simulations and laboratory testing were carried out in order to understand the basis of the tunnel lining mechanical behaviour response. A series of flexural bending laboratory testing conducted by the authors was also presented to discuss the mechanics of segmental tunnel lining along the longitudinal joints. In conclusion, results indicate that the measured curvatures and deflections are nonlinearly changed with the increased of applied loads. Different support systems show that appropriate joints could help reduce the maximum moment but an excessive allowable joint movement could lead to high flexural moment which could endanger the global structure stability.

The transportation infrastructure, including low-volume roads in some regions, needs to be constructed on weak ground, implying the necessity of soil stabilization. Untreated and cement-treated lateritic soil for low-volume road suitability were studied based on Malaysian standards. A series of unconfined compressive strength (UCS) tests was performed for four cement doses (3%, 6%, 9%, 12%) for different curing times. According to Malaysian standards, the study suggested 6% cement and 7 days curing time as the optimum cement dosage and curing time, respectively, based on their 0.8 MPa UCS values. The durability test indicated that the specimens treated with 3% cement collapsed directly upon soaking in water. Although the UCS of 6% cement-treated specimens decreased against wetting–drying (WD) cycles, the minimum threshold based on Malaysian standards was still maintained against 15 WD cycles. On the contrary, the durability of specimens treated with 9% and 12% cement represented a UCS increase against WD cycles. FESEM results indicated the formation of calcium aluminate hydrate (CAH), calcium silicate hydrate (CSH), and calcium aluminosilicate hydrate (CASH) as well as shrinking of pore size when untreated soil was mixed with cement. The formation of gels (CAH, CSH, CASH) and decreasing pore size could be clarified by EDX results in which the increase in cement content increased calcium.

Inadequate characteristics of marine clay often lead to engineered structures being damaged. There is a need to perform soil improvement prior to any construction activity. This study intends to ascertain marine clay strength from samples obtained from the West-Coast Expressway (WCE) project; the samples are planned to be strengthened using magnesium chloride (MgCl2). Specifically, the determination of the compressive strength of magnesium chloride-treated marine clay is a key objective of the study. The testing process comprises lab assessment to ascertain the Unconfirmed Compressive Strength (UCS) to treated and untreated marine clay samples. Laboratory tests confirmed that, typically, marine clay treated with MgCl2 had enhanced strength. The UCS test indicated that an addition of 6% MgCl2 to marine clay led the strength peaking at 137 kPa.In contrast, the addition of MgCl2 upwards of 4% led to a decrease in strength. Marine clay treated with 6% MgCl2 recorded an increase in UCS to 137 kPa and 110 kPa at seven and three days of curing, respectively. Subsequently, at fourteen and eighteen days, the strength values were 132 kPa and 125 kPa, respectively. It indicates that, typically, there is an increase in strength till the seventh day of curing and, subsequently, strength values begin to decrease. The change in strength can be attributed to the formation of cementation products that lead to soil particles getting bound together, and they occupy the free space between clay particles and MgCl2. With an increase in positive surcharge, soil particles begin to repel, thereby leading to reduced soil strength.

This paper proposes a method to predict mechanical failure-mechanicsm. This method is capable of predicting failure mechanism of diverse geo-hazards, such as landslides, rock slope failures, etc. The method uses the displacement or strain divergence phenomenon in the fatal phase of failure to predict failure mechanism irrespective of failure mechanism, lithology and other parameters. Using the proposed method (RocSlope), prediction of failure mechanism of case histories was done (Rock mass failure and landslides) and laboratory studies (creep tests). In most cases, safe predictions were obtained. RocSlope, is a simple, quick and reliable practical method that revealed independency to volume of failure, lithology and failure mechanism. In addition, two empirical relations to estimate the terminal phase of failure and the critical deformation rate were developed, these practical relations complement the RocSlope method. This research will analysed rock orginally from a cool temperate region in West Hokkaido,Japan was presented. A rock slope deformations of jointed- chert rock were monitored using six surface fracturedisplacement sensors. Some movements that could be related to joint growth were observed. With the RocSlope, rock mass and rock deformations were numerically analysed and joints deformations were dominantly caused by thermal fatigue. Affects of the minor freezing on deformation of rock slope can be seen were observed.

Lime stabilisation of organic clay has often been studied in the past. However, there is some evidence in the literature that the presence of high concentrations of organic matter in clay soil can lessen the chemical reaction between lime and clay minerals and can have detrimental effects on the engineering properties of soil. Hence, in this paper, the stress–strain behaviour and strength properties of organic soil treated with lime and sodium chloride (NaCl) are analysed. A soil mixture, prepared with 5% lime content and 1·5% humic acid, was stabilised with varying quantities of sodium chloride (0·5, 2·0 and 5·0%). Consolidated undrained and drained triaxial tests were carried out on specimens at curing periods of 7 and 28 d with applied confining pressures of 50 and 100 kPa. Scanning electron microscopy and X-ray diffraction analysis were used to observe the microstructural changes resulting from cementation materials. It was found that the introduction of sodium chloride improved considerably the strength properties of the lime-treated organic clay. The microstructural analysis also confirmed the presence of calcium silicate hydrate in a salt-treated organic clay, which was the main contributing factor to the enhanced engineering properties of the clay.

Malaysia is anticipating an increase of 68.86% in CO2 emission in 2020, compared with the 2000 baseline, reaching 285.73 million tonnes. A major contributor to Malaysia&rsquo, s CO2 emissions is coal-fired electricity power plants, responsible for 43.4% of the overall emissions. Malaysia&rsquo, s forest soil offers organic sequestration of 15 tonnes of CO2 ha&minus, 1&middot, year&minus, 1. Unlike organic CO2 sequestration in soil, inorganic sequestration of CO2 through mineral carbonation, once formed, is considered as a permanent sink. Inorganic CO2 sequestration in Malaysia has not been extensively studied, and the country&rsquo, s potential for using the technique for atmospheric CO2 removal is undefined. In addition, Malaysia produces a significant amount of solid waste annually and, of that, demolition concrete waste, basalt quarry fine, and fly and bottom ashes are calcium-rich materials suitable for inorganic CO2 sequestration. This project introduces a potential solution for sequestering atmospheric CO2 inorganically for Malaysia. If lands associated to future developments in Malaysia are designed for inorganic CO2 sequestration using demolition concrete waste, basalt quarry fine, and fly and bottom ashes, 597,465 tonnes of CO2 can be captured annually adding a potential annual economic benefit of &euro, 4,700,000.

Tunnel excavation usually will causes soil redistribution and settlement. Hence, for urban areas where large building used pile for foundation, tunnelling might affect the pile integrity. Engineers pose great role in order to correctly estimating the stress changes onto pile structures. It is particularly vital to estimate the tunnelling effects when new tunnels are to be built near an existing pile. Therefore, this paper presents a physical modelling to investigate the tunnel-pile-soil interaction. Sand box test with pile and tunnel model was developed to imitate the field condition. The laboratory testing conducted with constant parameter tunnel cover to tunnel diameter ratio of 2.5 with pile to tunnel distance of 1.5 of tunnel diameter. Two rate of tunnel excavation were carried out. Laboratory tests determined the longitudinal and transverse ground surface settlement induced by tunnelling, as well as the movement and induced bending moment on a single pile foundation. For validation, initial results were compared with previous findings and shows an agreement. Further test then conducted with higher tunnelling speed. With higher speed, it was found that surface settlements, pile movements and bending moment are more affected.

Several studies have attempted to develop thresholds for prediction of landslide initiation due to antecedent rainfall by using the physical-based approach. The approach offers a better understanding of the underlying process of the landslide mechanism. In the previous studies, however, determinate values of hydro-mechanical soil parameters are commonly considered, neglecting the uncertainties of the variables. Thus, this study aims to propose a relatively computationally, inexpensive reliability approach to address the uncertainties of the multivariate. The application of the proposed model is demonstrated by taking a case study from Sabah, Malaysia. The Latin Hypercube Sampling was adopted for efficient sampling, while the dependencies of the multivariate were modelled using a higher-order copula. The infiltration process and slope stability were assessed based on a fully-coupled seepage-deformation and shear strength reduction technique, respectively in a finite element programme. The probabilities of failure for various antecedent rainfall condition were computed by using Monte Carlo Simulation. In order to reduce the computational cost of the simulation, the Multilayer Perceptron regressor was applied to form the non-linear surrogate model for an implicit limit state function.

Implementation of potential debris flow hazard in Malaysia has been conducted by Jabatan Kerja Raya in 2011. However, evaluation of this hazard level cannot deny the consequent to the nearest facilities. Thus, run-out analysis based on numerical modelling is the easiest and competent way to evaluate the risk level. There are more than 10 cases reported regarding debris flow occurrence from 1995 until 2015 in Malaysia. All these cases have caused severe damage to facilities and have involved a huge number of fatalities. Hence, an effective strategy is required on reducing the impact from these damages especially debris flow catastrophe. One of the structural measures for debris flow is a Sabo dam. This study presents a study on debris flow sedimentation volume with and without Sabo dam by numerical simulation using Kanako 2D software. Kanako 2D software is widely used in Japan and it is equipped with graphical user interface. A crossed verification upon numerical modelling and actual field data collection, and mitigation situation model that include Sabo dam has been conducted. Results show that Kanako 2D software has a precise output where the sedimentation volume is slightly higher in the range of 5 to 15 % compared to actual field data. It also proved that Sabo dam can reduce the impact of debris flow as it can bear the sedimentation volume about 91%.

The bending moment of tunnel lining can be influenced by non-uniform ground pressures and joint eccentricities. Influence of joint interaction that induces flexural moment behaviour in segmental tunnel lining was investigated for the project Circle Line Stage 3 (C852), Serangoon Interchange Station. By considering behaviour of segment joint (which can affects the tunnel circumferential and longitudinal safety in overall), the tunnel lining behaviour and displacement of the ground surrounding the tunnel were evaluated. The segment joint modelling in simplified dual-jointed model and in fully soil-tunnel model were developed to assess the effect of segment joint on the overall tunnel response. Ground deformation or settlement trough at the ground surface resulted from the effect of tunnel construction and interaction between soil, tunnel, segment joints and ring joints was predicted. Results showed that with different use of segment joints give different longitudinal settlement. Hinge-nonlinear model together with separated rings model lead to the highest resemblance of surface settlement pattern to the field data when compare to tie model.

Underground facilities and tunnels is not a rare discussion anymore. More and more underground explorations were carried out as to fulfil the need of mankind. In this paper, discussion on how to utilise tunnel and underground space knowledge in order to sustain green development thus to provide smart solution for infrastructure facilities (electrical cable, manhole etc ) is discussed. Types of tunnel and its excavation methods especially the recent micro-tunnelling method also presented. Affect to the green and sustainable development and case study are also presented.

The effects of variation of moisture content on the strength index are different depending on the type of rocks. Hence this paper compares effect of moisture content to the strength and anisotropy index of moderately weathered shale and sandstone of Jurong Formation. Both field and laboratory works had been carried out to in order to gain useful data such as the physical description, the strength index and also the anisotropy index of the rocks. Twenty-four samples of moderately weathered for each shale and sandstone (total 48 samples) were tested at a wide range of moisture content varying from original moisture content to saturated condition. The results revealed that the presence of water has affected the strength index of shale more than sandstone. The strength index of shale decreased up to 80% with just 7.4% increment of moisture content while the strength index of sandstone only decreased up to 46% by 6.94% increase in moisture content. The presence of water also affected the anisotropy index of the material. The results discovered that the presence of moisture content has affected the anisotropy index of shale more than sandstone. With original moisture content of 1.06% to moisture content of 8.45%, the shale is shifting from fairly-moderately anisotropic to highly anisotropic while sandstone that had not been affected much in term of anisotropy index still remain as fairly-moderately anisotropic material with 6.94% increase of moisture content. Field and experimental results shown the increment of moisture content has affected the strength and anisotropy index of shale more than sandstone of the same weathering grade. The impact of moisture content on tropical shale and sandstone strength index is required for the design and construction of foundations, tunneling and slope stability studies in rock mass.

The utilization of waste materials has been a sustainable approach to soil improvement that took an interest in a number of researchers. Statistics show that out of the 76 percent of solid waste that is collected in Malaysia, only 5% is recycled while 95% of waste were dumped at landfills. This shows that there is a need to reutilize waste materials. This paper aims to discuss the different types of waste materials which are demolished tile material (DTM), demolished concrete material (DCM) and coal ash waste to improve the properties of marine clay. Experimental studies have been conducted by varying percentages of waste materials ranging from 5 – 15% with curing periods of 0, 7 and 28 days. Unconfined compressive strength test (UCS) was performed in order to determine the strength of these mixtures. The results obtained were that for both DCM and coal ash waste when mixed with marine clay would increase the strength of soil with increasing curing period. While for DTM, the strength of soil decreases with the immediate addition of additive but will later increase its strength gradually. Hence, the outcome obtained from this study is that both DCM and coal ash is suitable for the stabilization of marine clay soil while DTM is suitable for long term stabilization on marine clay.

Driver Behaviour Questionnaire (DBQ) is the most popular self-report driving assessment tool globally for assessing crash risk and aberrant driving behaviours among motorists. Therefore, this study reports on the utilisation of the DBQ to examine the self-reported driving behaviours (and crash outcomes) of a sample of university students. Questionnaires which contains demographic questions and 36 items measuring driving behaviour (including driving distractions, violations, errors and lapses) in traffic were distributed manually to participants. The findings show that distractions factor is most frequently reported items among all of the respondents (M = 4.11). Besides, there are also significant association among the demographic factors such as ‘driving experience’ and ‘vehicle type’ with gender of respondents. Meanwhile, there is no significant association between ‘accident involvement’ with gender of respondents. In terms of driving behaviour comparison, the behaviour among male drivers is significantly different compared to female drivers in all the scores and the constructs ‘violations’, ‘errors and ‘lapses’ except for the construct ‘distractions’. Meanwhile, there is no significant difference between drivers who have and have not possessed valid driving license in all driving behaviour.

Soft ground tunnelling describes as additional measures that are needed to be taken as it has been associated with settlement due to changes of stress and strength of the soil induced by tunnelling. Segmental tunnel lining is a structure used to support the ground and to have allowable movement due to soil stress redistribution. The research will be focusing on the type of modelling, structure parameter of the tunnel, pressure upon the tunnel lining and relationship with the induced ground settlement. Tunnel modelling was done in three dimensional (3D) modelling using ABAQUS software; of tunnel as parameter. This paper will discuss the effect of jack forces to the global behavior of the tunnel in order to support the surrounding load, thus be able to handle the tunnel-soil reaction without any visible or critical deformation, so that the tunnel can be used in the stable condition. A stand-alone ring method together with all-in-once method was used to simulate the Singapore MRT Circle Line 3 (CCL3). In the findings, when the tunnel lining thickness is reduced, the settlement of the ground surface is increased. Jack forces is also one of the reason of the tunnel to distort and the effect is more visible on the rings with reduced thickness compared to original thickness of the tunnel lining.

Conventional lining design usually considers tunnel lining as a uniform rigid ring model by implying high partial safety factor on the bending moment which is overestimated, due to inaccurate assumptions. To overcome this problem, investigation on the influence of joints on the behaviour of the global lining is significantly important especially when the interaction between segments is included. This paper presents investigation in tunnel segment joint influence on global tunnel lining behaviour especially when the interaction between segments becomes nonlinear, in different type of soil, so that more realistic soil-tunnel lining response can be obtained. The effect of segment joint parameters (linear or nonlinear) and soil parameters was investigated via numerical modelling. The predicted stress and displacement results from the numerical model were verified with the result obtained from field data collection. FEM model of original soil and settlement monitoring data depicted similar pattern of settlement but the FEM model did not captured the sudden settlement at the distance of 40 m from starting point. This was due to the simplification of FEM model and assumption of greenfield. The sand model gave similar result pattern like original case study soil behaviour. Clay model, in opposite, showed heaving at the beginning of construction that caused by the pressure induced by the weight of concrete and moving the water pressure toward the ground. One could conclude that, the elastic settlement profile occurred due to selected parameters of soil and Mohr Coulomb model.

Slope failure is one of the major geological phenomenon that happen due to the topography and weather conditions which cause a wide range of ground movements which needed engineers to plan in order to avoid its risk on human lives and properties by an appropriate stabilizing method. Soil nailing system is considered as one of the major preventive methods and economic systems to overcome the slope failures. In this paper, soil nailing system was studied in term of inclination to determine the most appropriate values for effective stabilization of soil slope using the SLOPE/W software. To validate the results, different soil nail inclinations were applied to a case study, and the Factor of Safety (FOS) of the case study was evaluated as well. The case study is located at Genting Highlands, Pahang. Results showed that the soil nails inclination has significant effect on the stability of the soil slope. For soil slope with steepness of 30°, 45° and 60°, the best FOS found with soil nail inclination (to the horizontal) of 60°, 50° and 40° respectively. The effect of soil nails inclination gives small difference in FOS when the degree of inclination of the soil nails varies within 5° - 20° to the horizontal.

Screw Driving Sounding (SDS) test has been developed in Japan as the improved version of the Swedish Weight Sounding (SWS) test. The development of SDS is to reduce the drawbacks of the SWS with the integration of rod friction estimation. Deep boring with Standard Penetration Tests (SPT) together with soil sampling for laboratory tests have been the common procedure for determining the subsurface soil profile and geotechnical engineering properties. However, the SPT which is associated with deep boring, uses high fossil fuels, needs high skilled workers and expensive. This paper presents the SDS technology and the SDS test results in comparison with the existing SPT data from six (6) selected sites in Malaysia. Results show that there is a strong correlation between SPT and SDS data, and the soil profile is better identified using SDS than the SPT. It is predicted that SDS test has the potential to replace conventional soil investigation methods, particularly in soft soils area. It is not just fast, cheap and does not require highly skilled workers but SDS tests supports green technology and sustainability in construction. Quality results are guaranteed from the usage of Industrial Revolution 4.0 technology through automation in testing and making use of the cloud computing to manage the data.

Generally tunnelling in urban ground condition is not always favourable due to the tunnels’ susceptibility to major displacement especially when excavated in the soft soil and/or weak weathered rock formation. Apart from conventional support systems, pre-support measure like forepoling umbrella arch is frequently used to reinforce the ground. Modern computational tools allows the inclusion of multi-stage excavations and pre-support which was not possible in two dimensional (2D) plane strain. This paper demonstrates the three dimensional (3D) finite element analysis of Pahang-Selangor raw water transfer tunnel, as a reference case, where multi-stage excavation and pre-support are incorporated as intrinsic part of the model. The New Austrian Tunnelling Method (NATM)-3 segments which encountered Grade III weathered granite, having shallow overburden cover, was selected for numerical analysis using RS3 software. Comparison between simulated and observed data has shown good agreement during verification

In view of the large movement required to mobilise the base resistance of bored piles and difficulty in base cleaning, the end bearing resistance often ignored in current design practice that will result in excessive rock socket length. Many attempts have been made to correlate the end bearing resistance with the uniaxial compressive strength of intact rock and the RQD but it is uncertain how applicable they are to rock type in Malaysia. This paper attempts to review the applicability of the formulas from previous studies to rock type in Malaysia. A program of field tests for 13 bored piles with diameter varying from 1000 mm to 1500 mm constructed in granite was conducted to measure the axial response of bored piles, tested using static load test and high strain load dynamic test to verify its integrity and performance. The results were evaluated and compared to the predicted rock bearing resistance. Based on the result obtained, the method by AASHTO gives the best prediction of rock bearing resistance for granite in Malaysia. However the relationship between compressive strength and rock discontinuities with the rock bearing resistance showed scattered results

Tunnel lining design is an interactive problem, which is not merely about the strength, but how much the lining could deform to accommodate the ground movement. When tunnel interacts with soil, stress from the ground is distributed onto the structure. In precast segmental tunnel lining, it is critical to investigate the lining reaction when applied with load, as this affects the overall flexural behaviour of tunnel lining. The objective of this paper is to understand the basis of tunnel lining mechanical behaviour response. A series of conducted flexural bending laboratory testing and developed numerical models presented here in order to discuss on the mechanics of segmental tunnel lining. By having two different support mechanisms, variation trend in load-deflection and moment bending curve depicted. Mirror trend of pin-pin support can easily be spotted in the results indicated segment lining affected by the load and support design.

Series of laboratory testing on the investigation of soil liquefaction using cyclic triaxial test had been carried out by researchers around the world but many of the results are contradictory. Thus, it is important to first determine the condition in which the clean sand is most susceptible to liquefaction, then only the liquefaction susceptibility of sand matrix soils could be compared and discussed under this specific condition. This paper presents the undrained behaviour of Johor sand and sand mixed with fines (kaolin) from cyclic triaxial tests. Stress controlled triaxial test apparatus was used to shear the isotropically consolidated soil samples under undrained two-way cyclic loading until the initiation of liquefaction. The liquefaction was defined based on: (i) excess pore pressure was equal to effective confining pressure or (ii) double amplitude strain of 5 % was reached, whichever was achieved first. The results of two-way cyclic triaxial tests on clean sand showed that besides the cyclic stress ratio, the liquefaction resistance of the sand under undrained loading was proportional to effective consolidation pressure and density index. The Johor sand was more liquefiable at its loose state and under low effective consolidation pressure, when subjected to earthquake loading.

Tunnel lining design requires an interactive approach as the design is not merely about the strength, but how much the tunnel allows to flexure to overcome the ground movement. When tunnel interacts with soil, stress from the ground is distributed into the structure. In the case of precast segmental bolted tunnel lining, it is critical to investigate the lining joints reaction, as this affects the overall flexural behaviour of tunnel lining. The objective of this paper is to present a discussion on the mechanics response of segmental tunnel lining affected by the segment’s joint. A short review on research works conducted in recent day on joint effect in segment’s joint in tunnel lining is also presented.

Pre-test treatment prior to soil index properties testing particularly pre-drying plays an important role in order to obtain accurate and reliable results. According to British Standard, BS1377:1990-Part 1, soil sample shall be dried by either air drying or oven drying before testing. However, permanent alteration of soil physical properties will eventually influence the characteristic and behavior of the soil. Hence, effect of pre-drying conditions on the soil index properties is studied on three number of disturbed clayey soil samples pre-treated in five (5) different pre-drying conditions at different temperatures and drying duration. Soil specimens were tested based on index properties in accordance to BS1377:1990-Part 2. The results obtained revealed that increase of pre-drying temperature and duration has significant effect on the plasticity index of about 13%, shrinkage limit of about 4% and the classification of the clayey soils consisted higher percentage of fine particles. Conclusively, oven drying method should not be used in soil preparation for plasticity and shrinkage testing.