Frozen Soil Lateral Resistance for the Seismic Design of Highway Bridge Foundations

INE/AUTC 12.3

Experimental analysis of 3D cracking in drying soils using ground-penetrating radar

This paper describes the capabilities of a novel technique to investigate crack formation and propagation in drying soils. The technique is a relatively simple, non-destructive indirect technique using a ground-penetrating-radar (GPR) system to detect cracks that form and propagate inside a soil specimen during desiccation. Although GPR devices have been used for multiple applications, their use in soils for the detection of small desiccation cracks has not been demonstrated yet. The experiment and the methodology used to test the accuracy of a small compact commercial GPR device for crack identification are described. The main objective was to identify what type of signals and what crack width and separation between them can be detected using the GPR device. The results indicate that cracks of 1 or 2mm wide can be detected depending on its position and shape, whereas sub-millimeter cracks are undetectable with the currently existing devices in the market. Regardless of this limitation, the GPR method can be useful to find time-related bounds of when the cracks appear, to point at their location and sometimes at the separation between two of them. Detection of cracks with origin at the bottom or within the specimen was accomplished with this system. Distances of 5 cm or more between cracks can be detected and measured, as well, with accuracy.Peer ReviewedPostprint (author's final draft

Studies on Hong Kong hepatics : 2., notes on some newly recorded liverworts from Hong Kong

Based on field work and herbarium studies, 44 species belonging to 21 genera and 11 families of hepatics are newly reported for Hong Kong. A first checklist of liverworts and hornworts in Hong Kong is also included

Kesediaan pelajar terhadap kit 'Smart CCTV' bagi pelajar teknologi elektronik di Kolej Vokasional

Penggunaan alat bahan bantu mengajar (ABBM) dalam pengajaran perlu dipelbagaikan bagi memudahkan dan membantu pelajar dari segi kefahaman yang mendalam dalam subjek yang dipelajarinya.Kajian ini ingin membangunkan satu produk Kit ‘Smart CCTV’ sebagai ABBM dan mengkaji persepsi pelajar mengenai kefahaman kepada pelajar terhadap topik Pemasangan Perkakasan Elektronik sistem litar tertutup televisyen (CCTV) dari segi domain kognitif, afektif dan psikomotor bagi pelajar aliran Teknologi Elektronik di kolej vokasional. Reka bentuk kajian ada dua bahagian iaitu reka bentuk pembangunan produk yang menggunakan model ‘Rapid Prototype’dan kajian deskriptif kaedah tinjauan untuk kajian keseluruhan. Analisis kajian ini menggunakan kaedah deskriptif kekerapan, peratusan, skor min dan sisihan piawai yang menggunakan perisian Microsoft Office Excel 2016. Reka bentuk pembangunan produk kit ‘Smart CCTV’ amat sesuai sebagai ABBM. Dapatan analisis bagi persepsi pelajar terhadap penggunaan ABBM keseluruhannya skor min ketiga-tiga domain; kognitif, psikomotor dan afektif, masing-masing mempunyai skor min 3.25, 3.21 dan 3.30, maka ketiga-tiga domain memberikan kesan yang sama terhadap pelajar berkenaan dengan penggunaan ABBM kit ‘Smart CCTV’. Hasil kajian ini diharapakan dapat dijadikan sebagai satu garis panduan kepada guru di kolej vokasional untuk menggunakan ABBM dalam PdP serta panduan kepada pengkaji lain untuk meneruskan kajian berkenaan dengan penggunaan ABBM terhadap pencapaian pelajar

Numerical analysis of desiccation, shrinkage and cracking in low plasticity clayey soils

This paper presents a numerical study of the desiccation processes of low-plasticity clayey soils that usually result in shrinkage and often in cracking. For the theoretical development of the numerical model, concepts of Unsaturated Soils Mechanics and of classical Strength of Materials are used as a framework for formulating phenomena such as water flow in deformable porous media and cracking. The mathematical formulation of the problem and its implementation in a hydro-mechanical coupled model is presented, in order to simulate fluid flow and cracking in soils, for which the FEM and the node release technique is combined. The code developed has been used to perform several numerical analyses on radial sections of cylindrical soil specimens subjected to a drying process for which experimental laboratory data was available. The objective of these simulations is to determine the mechanisms by which the soil shrinks and cracks during desiccation. The results show the capabilities of the approach to reproduce the main features of the problem, with desiccation, shrinkage, and cracking being reproduced consistently during a desiccation cycle. The model also highlights the key role of the displacement and suction boundary conditions in the development of cracks as a consequence of tensile stress fields. Finally, the model has revealed the necessity of further research in the study of the soil-container and soil-atmosphere interaction in order to reproduce with more accuracy the changes in the main variable

Investigation of gold nanorods as a sensing material in plasmonic sensor for triclopyr butotyl detection

Gold nanorods (GNRs) have a unique optical property of metal nanoparticles (MNPs) due to the localised surface plasmon resonance (LSPR) effect, which depends on the size, shape and dielectric property of the surrounding medium. LSPR, or commonly known as the plasmonic effect, refers to the optical phenomena resulting from the interaction of free electrons on a nano-sized metal surface with incident light at specific wavelengths. The plasmonic effect of rod-shaped nanoparticles shows dual absorption bands corresponding to transverse surface plasmon resonance (t-SPR) and longitudinal surface plasmon resonance (l-SPR). These two bands are sensitive to size changes and the surrounding medium’s refractive index. In GNR formation, particles size, homogeneity and shape are crucial elements to be investigated during the synthesis process. Therefore, three parameters are studied in this research, which are centrifugation speed, seed solution concentration and growth solution ageing period. Through the variation of parameters during the synthesis procedure, the optimum GNRs with a surface density of 74.81 %, an average length of 59.80 ± 0.53 nm and an average width of 14.14 ± 0.19 nm produce an aspect ratio of 4.23 ± 0.36 via the seed�mediated growth method (SMGM). The optimum GNR sample is prepared by adding 10 µl of a seed solution into a raw growth solution and left undisturbed for 20 hours and then centrifuged at a rotational speed of 5000 rpm. The optical spectrum from that sample exhibits two plasmon bands at the transverse axis of 535.02 nm and the longitudinal axis of 782.65 nm. For sensing application, the GNRs are used as a sensing material to detect the targeted analyte, namely triclopyr butotyl (Cଵଷ Hଵ଺ClଷNOସ). The sensitivity, stability and repeatability of GNRs in deionized water and triclopyr butotyl medium is studied by observing the changes in the absorption intensity and the peak position of the plasmon resonance. The optical response of 10 % triclopyr butotyl without GNRs shows no significant peaks and proves that GNRs are able to increase the ability of detection through the plasmonic effect. In sensitivity testing, it is found that the presence of triclopyr butotyl changes the absorption intensity and shifts the resonance peak position of the GNRs. The vi detection limit of GNRs is as low as 3 %. Furthermore, the GNRs depict good response during 600 seconds of the stability test. Moreover, the fast response and recovery time in the change of medium observed in five cycles show good repeatability of GNRs

Kecerdasan emosi dalam kalangan pelajar Diploma Pendidikan Lepasan Ijazah (DPLI) Universiti Tun Hussein Onn Malaysia

Kecerdasan emosi dapat dijadikan sebagai panduan bagi mewujudkan pendidikan yang berkualiti serta sebagai asas pemerolehan ilmu pengetahuan bagi seseorang pendidik dalam menjalankan tugasnya sebagai seorang guru. Namun begitu, adakah faktor umur dan pengalaman seseorang pendidik menjejaskan kecerdasan emosi mereka apabila meneruskan pengajian di peringkat yang lebih tinggi? Oleh itu, tujuan kajian ini dijalankan untuk mengkaji tahap kecerdasan emosi pelajar Diploma Pendidikan Lepasan Ijazah (DPLI) Universiti Tun Hussein Onn Malaysia (UTHM) dengan menggunakan soal selidik berdasarkan model Goleman iaitu kesedaran kendiri, pengawalan kendiri, motivasi kendiri, empati dan kemahiran. Kajian tinjauan secara pendekatan kuantitatif ini melibatkan seramai 210 orang pelajar DPLI yang berbeza kursus. Data yang dikumpul telah dianalisis dengan menggunakan Statistical Package for the Social Science versi 16.0 secara analisis deskriptif dan analisis inferensi. Nilai min dikira bagi menentukan tahap kecerdasan emosi dalam kalangan pelajar DPLI. Hasil dapatan kajian menunjukkan bahawa tahap kecerdasan emosi dalam kalangan pelajar DPLI berada pada tahap yang tinggi (4.24). Hasil dapatan dari analisis inferensi iaitu ujian parametrik ANOVA menunjukkan bahawa tidak terdapat perbezaan yang signifikan berdasarkan umur serta pengalaman mengajar pelajar terhadap kecerdasan emosi. Oleh itu, keputusan analisis menunjukkan bahawa faktor umur dan pengalaman pelajar tidak menjejaskan kecerdasan emosi mereka dan tidak menghalang pelajar tersebut untuk cemerlang dalam pengajian yang diteruskannya

Laboratory study on the effects of hydraulic and granulometric parameters on the response of granular soil to internal erosion

Erosion is a major environmental problem to agricultural land as well as to civil engineering infrastructures. Rainwater infiltration into granular soils can lead to the migration of fine particles by suffusion. This experimental study is conducted to evaluate the susceptibility to erosion of cohesionless soils. The soil under investigation was collected from the coastal region of Mostaganem (West of Algeria) where erosion has recently caused several damages. To assess soil instability to erosion, two approaches have been proposed in the literature: the geometric approach and the hydraulic approach. Few studies have examined the combination of the two methods. The objective of our study is the combination of the two approaches by determining the critical hydraulic load responsible for triggering erosion as a function of soil characteristics. An experimental parametric study was conducted to determine the influence of initial amount of fines, hydraulic gradient and axial stress on the initiation and evolution of suffusion. A combination of the interactions between these parameters allowed us to express the critical hydraulic gradient and to identify the hydraulic behavior of the soil according to the studied parameters. This approach can better estimate the erodibility of cohesionless soils. It can be used in future development studies at this site to reduce the risk of erosion

On-sample water content measurement for a complete local monitoring in triaxial testing of unsaturated soils

To provide a complete local monitoring of the state of an unsaturated soil sample during triaxial testing, a local water content measurement device was adapted to a triaxial device comprising the measurement of local displacements (Hall effect transducers) and suction (High capacity transducer). Water content was locally monitored by means of a resistivity probe. The water content/resistivity calibration curves of an intact natural unsaturated loess from Northern France extracted by block sampling at two depths (1 and 3.3 m) were carefully determined, showing good accuracy and repeatability. The validity of two models giving the resistivity of unsaturated soils with respect to their water content was examined