Understanding the Use of Polycaprolactone in East Asian Structural Rhinoplasty: Questions and Answers

Surgery as an art in rhinoplasty involves grafting techniques wherein materials (usually autologous) are taken from the septum and supplemented by conchal cartilage. However, not all noses have adequate cartilage material. The quest for materials as possible replacement for human tissue have led to invention of synthetic (e.g. silicone, e-PTFE, porous polyethelene) and non-synthetic products (e.g. processed homograft and xenograft). In this era of advanced medical science, tissue engineering has started the use polycaprolactone (PCL) as a template and scaffold for tissue growth. Because of this characteristic feature, PCL as a mesh has a significant role in structural rhinoplasty. What is structural rhinoplasty? The surgical goal of rhinoplasty is to achieve functional improvement in breathing and aesthetic overall look, most notably the tip. The tip is determined by the final shape of the lower cartilage in its proper location - - but since the lower cartilage is a floating structure supported only by fibrous tissue and ligaments, there is a high incidence of tip drooping post op. So, the idea of structured rhinoplasty was conceptualized in 1997 by Dr. Byrd and popularized by Dr. Toriumi.1,2 A piece of central septum is harvested and fashioned as an extension of the caudal margin of the septum. This is called a septal extension graft (SEG) and the lower cartilage is sutured to the caudal margin of the SEG for better control of the tip. Since then, the technique has been the main workhorse support graft for the tip.3 (Figure 1) Why is structural rhinoplasty needed in East Asian noses? East Asian noses, particularly Southeast Asian noses are usually short and small, with low dorsum and upturned bulbous nose. Tremendous strength in the design of the structural support with its foundation base at the caudal septum should be achieved in order to elongate the nose, counter rotate and project the tip. (Figure 2) This is made possible by using the central harvested cartilage as a SEG attached to the residual strong dorsal and caudal strut.4 (Figure 3)

PEMANFAATAN LAHAN BEKAS TEMPAT PEMBUANGAN AKHIR DENGAN STABILISASI TANAH SECARA KIMIAWI

Landfill soil (TPA) has great potential of utilization in construction purpose. Landfill soil has similar characteristic with clay soil that has high water content also contain organic and inorganic material caused by garbage heap. One of the problem in utilizing landfill soil was the low quality of the soil that cause big settlement for the structure. Settlement was an important aspect in performing a construction. Soil stabilization for the landfill soil needed to decrease amount of settlement. Structure model using one, two, three, four floor of load and calculate the settlement occur on the heaviest load location of the foundation. Foundation base was circle and using shallow foundation reconsidering shallow foundation effective for four floor load. Chemical stabilization using 2 methods: Sodium Hydroxide 6% and Limestone 3-4,5%. Based on the calculation, found that Sodium Hydroxide is more effective in decreasing settlement occurred and able to decrease the settlement until 32,42% for the floor load. However, those methods can’t fulfil the 15 cm settlement limit. Tanah bekas tempat pembuangan akhir (TPA) memiliki potensi besar untuk dimanfaatkan dalam bidang konstruksi. Tanah bekas TPA umumnya memiliki karakteristik serupa dengan tanah lempung berkadar air serta memiliki material organik dan anorganik dari timbunan sampah. Salah satu masalah dalam memanfaatkan tanah bekas TPA adalah rendahnya kualitas tanah yang mengakibatkan penurunan besar pada struktur. Perbaikan pada tanah bekas TPA diperlukan untuk mengurangi besarnya penurunan yang terjadi. Penurunan merupakan aspek penting dalam suatu perancangan konstruksi, maka dari itu batasan pada penurunan ditetapkan untuk menghindari penurunan yang berlebihan yang dapat merusak struktur. Permodelan menggunakan beban struktur 1,2,3, dan 4 lantai dan dihitung penurunan yang terjadi pada fondasi dengan beban struktur terbesar. Penampang fondasi berbentuk lingkaran mempertimbangkan beban percobaan hingga 4 lantai cocok untuk fondasi dangkal. Stabilisasi tanah secara kimiawi menggunakan 2 metode yaitu Sodium Hidroksida 6% dan batu kapur 3-4,5%. Berdasarkan hasil perhitungan, didapati stabilisasi menggunakan Sodium Hidroksida lebih efektif dalam mengurangi penurunan tanah yang terjadi dan mampu mengurangi besarnya penurunan hingga 32,42% pada beban struktur 4 lantai. Namun, stabilisasi tanah menggunakan kedua metode belum dapat mencapai batas aman penurunan sebesar 15 cm.

SELECTION OF THE GROUND BASE MODEL IMPLEMENTED IN THE SCAD OFFICE

The article defines and compares the obtained sediments based on the results of applying the current regulatory methodology of the set of rules 22.13330.2016 "Foundations of buildings and structures" and numerical calculations using various models of the soil base implemented in the SCAD office software package, using the example of a frame-monolithic building of the residential complex which is called "Novaya zhizn" in Belgorod. A brief overview of methods for joint calculation of the foundation and aboveground parts using various models of the ground base: Pasternak with two bed coefficients, variable area bed coefficients in the sattilite CROSS program and the model of linear deformable half – space implemented in SP 22.13330.2016. Analytical calculation of the sediment value for set of rules 22.13330.2016 is performed "manually" by the method of layer-by-layer summation. The numerical calculation of the frame-monolithic building is performed as a single system "building-foundation – base". The values of sediments and bed coefficients C1 and C2 based on the results of numerical calculation are presented in the form of graphical isofields of displacements and bed coefficients. Based on the results of analytical and numerical calculations, the main conclusions are made and recommendations were presented on the applicability of each of the considered models of soil bases

Clearing a Path for Ground Heat Exchange Systems: A Review on Thermal Response Test (TRT) Methods and a Geotechnical Routine Test for Estimating Soil Thermal Properties

The performance of ground heat exchanger systems depends on the knowledge of the thermal parameters of the ground, such as thermal conductivity, capacity, and diffusivity. The knowledge of these parameters often requires quite accurate experimental analysis, known as a thermal response test (TRT). In this paper, after a general analysis of the various available types of TRT and a study of the theoretical basics of the method, we explore the perspective of the definition of a simplified routine method of analysis based on the combination of a particular version of TRT and the routine geotechnical tests for the characterization of soil stratigraphy and the ground characteristics. Geotechnical analyses are indeed mandatory before the construction of new buildings, even if limited to 30 m below the ground level or foundation base when piles are needed. The idea of developing TRT in connection with geotechnical test activity has the objective of promoting the widespread use of in situ experimental analysis and reducing TRT costs and time. The considerations presented in the present paper lead to reconsidering a particular variety of the TRT, in particular, the versions known as thermal response test while drilling (TRTWD) and TRT using heating cables (HC-TRT).

MODELING OF STRESS-STRAIN STATE OF HIGH-RISE BUILDING PILE RAFT FOUNDATION WITH INCOMPLETE PILE INSTALLATION

The object of the study is a pile-raft foundation or mat foundation 180 cm thick of a 25-storey building made of a reinforced concrete frame. When constructing a pile foundation, some of piles are not completely sank down to the reference points. In this connection, it is necessary to identify the reasons and load-bearing capacity of piles, given the soil compaction between piles and under their tips and the possibility of using such piles for further building construction.After studying the materials of soil investigation, the analysis of occurrence, composition, physical-mechanical properties of soils, and the pile field, the stress-strain state model is developed for the pile-raft foundation using the MicroFe software application with the development of design model for the foundation-base-building system.In the compacted soil state between the piles and under the pile tips, the conditions of the ultimate and service limit states are met at the actual depth of pile sinking for the raft foundation.

CALCULATION OF FOUNDATION BASES IN PERMAFROST SOILS

This article discusses the calculation of the Foundation base in permafrost soils.

Settlement Computation of Homogeneous Base

Purpose of reseach. This article proposes the development of a new methodology for determining the settlement of a homogeneous foundation base on the basis of the layer-by-layer summation method, which reduces the amount of calculations performed.Methods. The boundary of the compressible stratum can be determined graphically from the condition that the additional stresses are equal to half the natural stresses. Knowing the value of the depth of the compressible stratum, we can determine the total value of the coefficients included in the well-known formula for calculating the settlement of the base by the method of layer-by-layer summation. Having determined the value of the specified coefficient in the layer located directly below the base of the foundation, we introduce the coefficient Kα, which reflects the proportion of sediment in the layer under consideration.Results. The application of the developed coefficient Kα allows determining the base settlement by calculating the deformations of one soil layer located directly below the base of the foundation, which greatly simplifies the design of underground structures. As an example, we consider a foundation, the average pressure under the sole of which is 1200 kPa, the laying depth d = 2 m, the base is homogeneous with a deformation modulus of 20 MPa and a specific gravity of γ = 18 kN / m3. The settlement of the building-basement system was calculated by the method of layer-bylayer summation and the critical analysis of the results was performed. When calculating precipitation by the method of layer-by-layer summation according to the known formulas given in SP 22.13330. 2016 “Foundations of buildings and structures”, it was obtained a draft value of 9 cm. When calculating the base deformations according to the proposed method, the boundary of the compressible thickness Hc = 5.7 m was graphically determined. The coefficient value was 0.203, and the draft was 9 cm.Conclusion. The settlement values determined in accordance with current regulatory documents and the developed methodology are the same, which allows us to conclude that the proposed method has a sufficient degree of reliability and can significantly facilitate the process of determining the deformations of the base of buildings and structures.