Linear root water uptake by vegetation

The performance of a simple model with a linear root water extraction term that varies with time is presented in this paper. The research is based on the use of a one-dimensional form of Richard’s Equation for unsaturated moisture flow including a sink term. A numerical solution has been achieved via the finite element method for spatial discretisation along with a finite difference time-marching scheme. The model is assessed via a series of simulations of water uptake beneath uniform crop cover. A good correlation between the field data and simulated results has been achieved. This relatively straight forward approach is seemed more suitable for development and application to a range of geoengineering problems such as slope stability, shrinkage and heave prediction

INVESTIGASI SUB PERMUKAAN PADA LOKASI LONGSOR JALAN MEULABOH-TUTUT KM 65 MENGGUNAKAN METODE MASW

Pengetahuan tentang struktur lapisan bawah permukaan sangat diperlukan untuk memperkirakan tingkat kerawanan suatu daerah terhadap suatu kemungkinan terjadinya tanah longsor. Investigasi geoteknik tentang karakteristik fisis struktur lapisan bawah permukaan merupakan tahap awal yang harus memenuhi syarat dan ketentuan. Penelitian ini meggunakan metode MASW (Multichannel Analisys of Surface Wave), yang merupakan salah satu metode geofisika yang dapat digunakan untuk menentukan struktur bawah permukaan tanah. Untuk mengetahui secara jelas bentuk dan struktur lapisan material di bawah permukaan bumi, maka dilakukan penelitian dengan menggunakan metode MASW (Multichannel Analisys of Surface Wave). Metode ini dilakukan dengan memancarkan gelombang ke bawah permukaan perlapisan batuan. Respon tanah atau batuan direkam melalui geophone yang terpasang di atas permukaan tanah. Dengan mengukur sifat perambatan gelombang permukaan Rayleigh, melalui metode ini dapat diketahui parameter dinamik tanah kecepatan gelombang geser (Vs), Penelitian ini akan dilakukan di Desa Lancong, Kecamatan Sungai Emas, Kabupaten Aceh Barat. Ada dua titik/lintasan penelitian lapangan yang telah ditinjau yaitu dengan tujuan untuk memperoleh kecepatan gelombang geser (Vs) tanah pada lokasi tersebut. Setelah memperoleh data dari hasil pengujian MASW, selanjutnya data yang ada diinterpretasikan dengan menggunakan software SeisImager/SW dan selanjutnya dimodelkan ke dalam bentuk profil dua dimensi (2D) dengan menggunakan software Surfer. Hasil profil dua dimensi (2D) yang diperoleh pada lintasan 1 terdapat tiga jenis karakter tanah yaitu tanah lunak, tanah sedang dan tanah keras dan profil dua dimensi (2D) lintasan 2 terdapat dua karakter tanah yaitu tanah lunak dan tanah sedang. Data yang diperoleh oleh SeisImager yaitu nilai (Vs) yang kemudian dibandingkan dengan data N-SPT terdapat keserupaan yang sesuai dengan grafik masing-masing data

Simulation of vegetative induced deformation in an unsaturated soil

Problem statement: Tree root water-uptake increases soil strength by increasing the soil matric suction due to pore pressure dissipation in a soil mass, inducing increases in vertical total stress or water extraction, the effective stress to which the soil strata is subjected to may also increase. This causes volume change which might be detrimental to geotechnical structures and shallow foundation. Approach: This study proposed a methodology that can be used for the prediction of the root water-uptake and deformation. It was suggested that negative pore-water pressures can be estimated through two-dimensional governing equation for unsaturated soil and was converted to axi-symmetrical form due radially nature of tree roots. Results: The results of the root water-uptake analysis were then used as input for the prediction of ground displacements in a stress-deformation analysis. A volume change was modeled as a result of matric suction change caused by vegetative induced moisture migration. The proposed method was studied and tested against data collected on a case history involving a mature Lime tree on Boulder clay at Stacey Hall, Wolverton, England and mechanical properties of Boulder Clay. The recommended safe planting distance of trees of height, H, from buildings a distance, L, away is in form of L: H=0.5 m ratio. Conclusion: The predicted results from the two dimensional axi-symmetrical analyses agree well with the measured data in terms of both total vertical displacements and final water contents in the soil. Based on hypothesis, the numerical model developed provides practicing geotechnical engineers an effective tool for designing structures on vadose zones containing vegetation

Laminated Veneer Lumber (LVL) sengon: an innovative sustainable building material in Indonesia

Laminated Veneer Lumber (LVL) is recently available in Indonesian markets. The veneers are majority from Sengon wood (Paraserianthes falcataria), which is a fast-growing timber species native to Indonesia. Their use in practice is limited to non-structural components since Sengon wood species has low engineering properties and less resistance to termite attacks. The LVL production introduced few years ago has significantly improved both mechanical properties and durability as well as has expanded its utilization into various structural components. This remarkable improvement has made LVL Sengon wood as an innovative sustainable building materials in Indonesia. This paper summarized a series of authors’ work conducted since couple years ago to initiate the utilization of LVL Sengon in structural components such as shear walls and floor systems as parts of a project to develop its design standard. In addition, creep behavior of this LVL is also highlihgted here as this phenomenon is essential for designers and engineers to anticipate their designs within their service life. In particular, the test results showed that addition of diagonal members increased both racking resistance and equivalent viscous damping ratio of the developed LVL shear walls. And the LVL floor model which is composed of built-up box joists and plywood sheathing remained liniear-elastic under bearing load up to 18.75 kN/2

PSYCHOSOCIAL DEVELOPMENT PORTRAYED IN JANE AUSTEN’S EMMA

This paper investigates the bildungsroman phenomenon as depicted in Jane Austen’s Emma (1817) by consulting Erik Erikson’s theory of psychosocial development as a framework of analysis. The most two conflicting readings in this regard could be best seen in Buckley’s (1974) claim which excluded Emma from the bildungsroman, for the genre has always been associated with the protagonist’s physical quest seeking maturity and social integration. However, Kohn (1995) read Emma as a domestic bildungsroman when he argued that Emma did not have to travel physical distances to achieve her maturity. For Kohn, Emma matured within her social sphere. This paper particularly traced Emma’s psychological and social development since this type of development is the basic ingredient of any bildungsroman novel. This paper argued that Emma cannot be read as bildungsroman not because the protagonist did set on a quest, as Buckley claimed, but mainly because Emma did not develop a sense of psychological or social maturation. After placing Emma in Erikson’s developmental stages, the study revealed that she did not really mature neither she realized her own identity. This paper proposed that Emma should not be classified as bildungsroman because the heroine distorted the real meaning of maturity and social integrity.

The Influence of Albumin Level in Critically Ill Children to Length of Stay and Mortality in Paediatric Intensive Care Unit

BACKGROUND: The use of albumin in the critical care setting is a very controversial issue. Low serum albumin concentration in critical illness is associated with a poor outcome. AIM: We aimed to evaluate the influence of albumin level in critically ill children to the length of stay and mortality in the Pediatric Intensive Care Unit (PICU) Haji Adam Malik General Hospital, Medan, Indonesia. METHODS: The study used an observational method with a cross-sectional design. The population of the study was all patients with major postoperative surgery and critically ill that admitted to the PICU at Haji Adam Malik Hospital from the period of June 2008 to September 2008. The albumin level of the subjects was determined on the first day admitted. RESULTS: The group with hypoalbuminemia (< 3 g/dL) was given albumin supplementation according to a protocol in the PICU. The group with hypoalbuminemia have an average length of stay 7.6 days (9.7%) and mortality of 12 subjects (36.4%). The group with normal albumin level have 4.7 days (5.0%) and mortality 13 subjects (37.1%). There was no significant effect of albumin level to mortality. CONCLUSION: Albumin level did not affect the length of stay and mortality in PICU

Influence of vegetation induced moisture transfer on unsaturated soils.

This study explores issues related to the numerical simulation of moisture migration patterns in the unsaturated zone and in the vicinity of established vegetation. A one- dimensional water-uptake model was first developed to simulate moisture migration beneath uniform vegetation (crop) cover. The main thrust of the research was then to develop a practicable water-uptake model that can be used to simulate moisture migration patterns beneath mature trees. The moisture flow model used is based on Richard's Equation extended to incorporate a sink term and integrated with appropriate water-uptake models (i.e. ID, 2D, and 2D axi-symmetric form). A numerical solution was achieved via the finite element method for spatial discretisation along with a finite difference time-marching scheme. A series of numerical simulations have been presented that demonstrate the newly introduced sink term functioned correctly and that the model is capable of representing typical water extraction processes from a variety of crop types. A new two-dimensional axi-symmetric model was then developed and applied to simulate moisture migration near established trees. In particular, the approach adopted utilizes radial symmetry and assumes a linear distribution of water extraction rate with both depth and radius. The new model has been validated by direct comparison to field measurements recorded (by others) for mature trees located on a clay sub soil. The model has been shown to be capable of representing water-uptake over a full-annual cycle. Time dependent boundary conditions, based on rainfall data, and hysteresis effects have also been explored. Overall, a good correlation between field data and simulated results has been achieved. Hysteresis effects, when the soil has already experienced repeated wetting and drying cycles, were not found to be of great significance for the class of problem considered. The research also provides a preliminary assessment of the significance of tree induced water content (and therefore suction) changes on the stability of unsaturated soil slopes. The 'typical' example considered, indicated that relatively small suction changes (in the order of 10 kPa) can influence the factor of safety against slope failure by approximately 7%. These findings should be considered in addition to the variety of other vegetation related strength effects. In conclusion, a relatively straight forward approach to modelling water-uptake by vegetation has been developed. The resulting model is thought to be valuable for a range of geoengineering problems

Comparison for ease of insertion for laryngeal mask airway between trendelenburg and supine position for elective orthopaedic, surgical and gynecology surgery

The purpose of this study is to assess the ease of insertion of the Laryngeal Mask Airway (LMA) between supine and trendelenburg position in the elective Gynecology, Orthopedic and General surgery patient. We measured easiness of insertion, incidence of adverse respiratory complication and hemodynamic response to LMA insertion. A randomized single blinded prospective study was conducted involving a total of 92 premedicated, ASA 1 or 11 patients, aged 18 to 65 years and were divided into 2 groups either insertion in supine or trendelenburg position. After a standardized induction of anesthesia with Fentanyl 1.5 meg/kg and propofol 2 mg/kg, a size 3 or 4 Laryngeal mask airway was inserted and the patient breathe spontaneously through the surgery with no muscle relaxant given. Anesthesia was maintained with nitrous oxide, oxygen and servoflurance. The LMA was removed at the end of surgery with the patient fully awake. The speed and ease of insertion and the number of attempts needed to successfully secure airway were recorded. The incidence of adverse respiratory complications like sore throat, presence of blood on LMA, laryngospasm, coughing, vomiting and desaturation was recorded. Hemodynamic changes such as systolic blood pressure, diastolic blood pressure, mean arterial pressure and heart rate at the different time interval were recorded. We found that there was no statistically significant difference in time required for successful insertion and number of attempts for both group. We were able to insert LMA at frrst attempt in 73.9% within 20.20 seconds in trendelenburg position. There were no differences in incidence of adverse airway complication both in supine and trendelenburg position. Both groups had no statistical differences in hemodynamic parameters during spontaneous ventilation under anesthesia except systolic blood pressure and mean arterial pressure just after LMA insertio~ which had statistically significant. We conclude that, insertion of the LMA in trendelenburg position is appropriate provided with a good experience and proper patients selection and strongly indicated in the scenario of fail intubation and ventilation as an alternative to the conventional method of LMA insertion