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The Chao Phraya River flows in the largest river basin of Thailand and represents one of the important agricultural and industrial areas in Southeast Asia. The Ping River is one major upstream branch flowing down slope southwardly, joining the Chao Phraya River in the low-lying central plain and ending its course at the Gulf of Thailand. Surprisingly, the overflow occurs frequently and rapidly at the Lower Ping River where channel slope is high, and in particular area, sand-choked is extensively observed, even in normal rainfall condition. In contrary, at the downstream part, the erosion of river bank and shoreline around the mouth of Chao Phraya River has been spatially increasing in place where there should be a massive sediment supply to form a delta. Here we use Landsat imageries taken in 1987, 1997, 2007 and 2017 to analyze geomorphological changes of rivers. Results show that both rivers have undergone the rapid decreasing of water storage capacity and increasing of sand bar areas in river embayment. The total emerged sand bar area in the Lower Ping River increases from 1987 to 2017 up to 28.8 km2. The excessive trapped bed sediments deposition along the upper reaches is responsible for the shallower of river embankment leading to rapid overflow during flooding. At the Chao Phraya River mouth, a total of 18.8 km2 of the coastal area has been eroded from 1987 to 2017.This is caused by the reducing of sediment supply leading to non-equilibrium in the deltaic zone of the upper Gulf of Thailand. There are several possibility implications from this study involving construction of weir, in-channel sand mining, reservoir sedimentation and coastal erosion management.

One devastating landslide event in northernThailand occurred in 2006 at Ban Nong Pla village, ChiangKlang highland of Nan province after, a massive amountof residual soil moved from upstream to downstream, viacreek tributaries, into a main stream after five days of unusualheavy rainfall. In this paper, the geological and engineeringproperties of residual soil derived fromsedimentaryrocks were analyzed and integrated. Geological mapping,electrical resistivity survey and test pits were carriedout along three transect lines together with systematiccollection of undisturbed and disturbed residual soilsamples. As a result, the average moisture content in soilis 24.83% with average specific gravity of 2.68,whereas theliquid limit is 44.93%, plastic limit is 29.35% and plastic indexis 15.58%. The cohesion of soil ranges between 0.096–1.196 ksc and the angle of internal friction is between 11.51and 35.78 degrees. This suggests that the toughness propertiesof soil change when moisture content increases. Resultsfrom electrical resistivity survey reveal that soil thicknessesabove the bedrock along three transects range from2 to 9 m. The soil shear strength reach the rate of high decreasesin the range of 72 to 95.6% for residual soil fromshale, siltstone and sandstone, respectively. Strength ofsoil decreaseswhen the moisture content in soil increases.Shear strength also decreases when the moisture contentchanges. Therefore, the natural soil slope in the study areawill be stable when the moisture content in soil level isequal to one, but when the moisture content between soilparticle increases, strength of soil will decrease resultingin soil strength decreasing.

Recent centuries provide no precedent for the 2004 Indian Ocean tsunami, either on the coasts it devastated or within its source area. The tsunami claimed nearly all of its victims [...]

Background: Rotational malalignment of a femoral component may lead to chronic pain, patellar maltracking, knee instability, and early failure of a total knee arthroplasty [TKA], The transepicondylar axis of the femur is widely accepted as a good reference for rotational alignment of a tibial component, although it is more controversial for a tibial component. Objective: This study aimed to determine the degree of rotational mismatch between femoral and tibial components implanted using the center-post self-align technique. Materials and Methods: Patients who underwent TKA for osteoarthritis of the knee were enrolled to have postoperative CT scans for determination of the rotational alignment. The study included 51 patients (60 knees), 5 males and 46 females, with a mean age of 64.0 years (range 58 to 73). The posterior cruciate ligament substituting tibial component position was set using the center-post self-align technique. CT digital images in the supine position with the knee at full extension were evaluated. Results: Of the 60 TKAs, the mean rotational mismatch between tibial and femoral prostheses was 2.00° (SD+O.340, range 0.1° to 5.8°). The femoral component was rotated externally and internally within 1.5° while the tibial component was within 2.59° relative to the transepicondylar axis. All knees had good patellar tracking intraoperatively without any lateral release procedure. Conclusion: The center-post self-align technique can achieve good compatibility of rotational alignment between the femoral and tibial components with low variability, particularly with the knee in the extended position. [ABSTRACT FROM AUTHOR]

Locating suitable caves and stalagmites for palaeoenvironmental and palaeoclimatic studies can be challenging. Isotopic geochemical analyses, albeit commonly performed for palaeoclimatic reconstruction, are also time consuming and costly. Therefore, petrographic and non-destructive morphological studies on speleothems are desirable to facilitate sample selection for further analysis. In this study, 20 caves were surveyed in Ban Rai district, Uthai Thani province in western Thailand. After external physical observations in the field, three stalagmite samples were collected from Tham Nam Cave to test their potential for palaeoclimatic research. Firstly, the stalagmites were scanned by X-ray computed tomography ( CT scanning) and subsequently the CT images were compared with petrographic inspections. Columnar fabrics show the highest density, whereas closed and open dendritic fabrics have medium and the lowest densities, respectively. Layers near the top and bottom of the three stalagmites were dated by U-Th mass spectrometric techniques. All three samples were deposited between c. 87 and c. 105 ka ago; therefore, they are probably the oldest stalagmites that have been reported so far from mainland Southeast Asia. However, their physical features indicate that all the samples have suffered from postdepositional dissolution, and are unlikely to be suitable for palaeoclimatic research. The internal dissolution feature of stalagmites, however, cannot be identified by visual inspection of uncut samples. We hereby argue that CT images are useful to characterize stalagmite petrography, in particular fabric, porosity and density. Such features can be used to select the ideal plane of a stalagmite for sectioning, to maximize the chances of robust climatic reconstruction. [ABSTRACT FROM AUTHOR]