Cyclic loading of tendon fascicles using a novel fatigue loading system increases interleukin-6 expression by tenocytes

Repetitive strain or ‘overuse’ is thought to be a major factor contributing to the development of tendinopathy. The aims of our study were to develop a novel cyclic loading system, and use it to investigate the effect of defined loading conditions on the mechanical properties and gene expression of isolated tendon fascicles. Tendon fascicles were dissected from bovine-foot extensors and subjected to cyclic tensile strain (1 Hz) at 30% or 60% of the strain at failure, for 0 h (control), 15 min, 30 min, 1 h, or 5 h. Post loading, a quasi-static test to failure assessed damage. Gene expression at a selected loading regime (1 h at 30% failure strain) was analyzed 6 h post loading by quantitative real-time polymerase chain reaction. Compared with unloaded controls, loading at 30% failure strain took 5 h to lead to a significant decrease in failure stress, whereas loading to 60% led to a significant reduction after 15 min. Loading for 1 h at 30% failure strain did not create significant structural damage, but increased Collagen-1-alpha-chain-1 and interleukin-6 (IL6) expression, suggesting a role of IL6 in tendon adaptation to exercise. Correlating failure properties with fatigue damage provides a method by which changes in gene expression can be associated with different degrees of fatigue damage

Sistem Pendukung Keputusan Alternatif Pemeliharaan Gedung Sekolah (Studi Kasus: Sltp Negeri I Pakem)

The performance of the building declines in line with the age of the building. To maintain the performance of the building, the building maintenance should be carried out. For this reason, an adequate program that able to analyze cost as well as condition of the building has been developed in this research. The assessment was carried out in a secondary school building in Pakem Sub Regency of Yogyakarta. The research used Analyzes of Hierarchy Process (AHP). Besides, the maintenance cost was also considered in the analysis. The secondary school has several buildings. Each building consists of structural, architectural and utilities components. This research mainly studied the performance of the architectural components rather than other components. The architectural components consists of classrooms, office rooms and supporting rooms. In every room, architectural element such as ceiling, wall, window, door and floor are subdivided into their accompanying elements. The elements were then weighted in accordance with their functions. The severities of their conditions were assessed in terms of percentage of the deterioration. The residual condition was determined by reducing the index condition (100 is best condition). The accumulative index condition was then represented the condition of every room. The determination of the priority was carried out on the basis of the ratio between increment of the condition (from the existing condition to the best condition) and the cost implied on the maintenance. The priority would go to the highest ratio. An analysis result indicate that among 37 rooms perceived, the class rooms obtained first priority followed by office room and then supporting room. The three first sequence priority among sixteen class rooms are classroom VIIA, the natural science laboratory and classroom IIIA. Among four rooms in office room groups, three first priority are Teacher room, Administration room, Headmaster room, and among seventeen room of supporting room groups, the three first priorities are parking area, canteen room, medical room

Karakteristik Dinamik Dan Estimasi Kekuatan Sisa Rangkaian Balok Beton Bertulang Menggunakan Mode Kelengkungan Eksperimental = Dynamic Characteristic and The Residual Strength Estimation

ABSTRACT The damage or crack on reinforced concrete structure causes strength deterioration of the structure. It will result in degrading of stiffness and strength of the overall structure. Therefore, a simply periodical detection of the strength could be developed. This research was carried out to study the dynamic characteristic of grid structures to investigate natural frequency, damping ratio, mode displacement, and dynamic residual strength of the damage structural system. A series of 4 sets of reinforced concrete beams (grid system) was used as the model in this research. Each beam consisted of two 3200 mm longitudinal beams which connected by five 400 mm diagonal beams (diaphragm). The longitudinal beam cross section was 90/200 mm and the diagonal beam cross section was 80/140 mm. These models were tested with gradually static loading. Meanwhile, to measure natural frequency and displacement for each level of crack, a dynamic loading test was applied. The dynamic loading is a sinusoidal loading at frequency of 15 Hz which was lower than the natural frequency system. The lower frequency was governed in order to get any measurrement in the first mode of the structural system. Based on the test result the following conclusions were deduced: (a) natural frequency of the damage system was smaller than original structural system, and related to the level of damage. The decreases of the natural frequency of GRD-1, GRD-2, GRD-3, and GRD-4, were 1556%, 6.25%, 14.1%, and 17.78% respectively, (b) mode displacement of the damage system was found to be greater than the original structur, depending on the level of damage,(c) first crack load of the structure system had been found about 26.1% Pmax to 47.6% Pmax, (d) location of crack and dynamic residual strength of damage system at the first crack had been detected but required verification for further crack, (e) the residual strength which was estimated from the static data (load-displacement), the dynamic test data (natural frequency) as well as the dynamic result (absolute different betwen the curvature mode shape) showed a realistic result at the initial damage condition. However, it could be unrealistic at the consecative level of damage. Key words : grid system, natural frequency, displacement mode, curvature mode, residual strengt

Pengaruh Fireproofing Pada Perilaku Pelat Beton Normal Dengan Tulangan Mutu Tinggi = The Effect of Fireproofing on the Behavior of Reinforced Concrete Slabs Using High Strength Steel Wire

Reinforced concrete slabs using high strength steel wire could be unsatisfying under high temperature due to the larger surface area of exposed concrete in comparison to other structural elements. One of several efforts on delaying heat transfer is done by applying extra cover to the concrete surface using fireproofing material. On that way, it is important to study the physical properties, such as strength behavior and heat transfer resistant of fireproofing material in order to comply with the code of practice. Nine specimens of reinforced concrete slab were designed and arranged. Each sample had dimension of 120 cm x 60 cm x 6 cm (length x breadth x thick), a compressive strength of 26 MPa, with the steel wire reinforcement of 39 mm diameter and the yield stress of 600 MPa. The concrete cover varied in four types, e.i: the standard 10 mm concrete cover, 20 min concrete cover, 10 mm concrete cover+10 mm plaster, and 10 mm concrete cover+l0 mm fabricated fireproofing. The standard heat curve of ASTM E-119 for 2 hours was adopted. The test results showed that the temperature distribution could be expressed as an exponential curve, which went down and became asymptotic with the depth of the concrete. The specimens, which was exposed to fire for 30 minutes with maximum temperature of 716°C, resulted in the deflection of 137% bigger than the maximum limit (L/360). ⢠The flexural strength and the compressive strength of concrete decreased to 92% and 79,5%, respectively, while the yield stress of reinforcing wire decreased to 91%. Crack pattern about the flexural load continued the previous crack during fire expose. The addition of concrete cover reduced further the temperature and the deflection to 40% and 45% respectively. The standard concrete cover with addition of plaster reduced further the temperature and the deflection to 47% and 36% respectively but increased the flexural strength after fire expose up to 106%. The standard concrete cover with addition of fabricated fireproofing reduced further the temperature and the deflection to 65% and 92% respectively but increased the flexural strength after fire expose up to 104%. It could be concluded that the concrete cover with addition of fabricated fireproofing material will be the most effective effort on delaying heat transfer on the slab. Keywords : fireproofing, concrete cover, exposed concrete, heat transfer

Tuned Mass Damper on Reinforced Concrete Slab with Additional “X-Shaped Metal” Absorber

AbstractThe problem of excessive structural floor vibrations due to human activities is critical because it results in excessive interference response at specified frequencies. Excessive vibrations can occur in slab systems with low stiffness or a low damping ratio. Increasing the stiffness of the slab is one method which can be used to reduce excessive floor vibration. In some cases this is, however, not possible because the additional mass of the stiffening structure will indirectly increase the overall mass of the structure; therefore, it will increase the stress of the structural elements. Other methods are using passive, active and semi-active dampers. This study used a passive damper system named tuned mass damper (TMD) with an additional “X-shaped metal” absorber as an additional damper which was applied to the concrete slab having a dimension of 4 m in length, 0.90 m in width and 0.08 m in thickness. This research showed that the mass ratio of the TMD to slab (μ) of 2.00% with a spring stiffness (k) of 80.281kN/m could increase the damping ratio of the slab from 1.82% to 2.06%. The TMD with the additional “X-shaped metal” absorber resulted in the damping ratio of 3.40%

Perhitungan Indeks Kondisi Bangunan dan Analisis Biaya Perbaikan Gedung Akademi Keperawatan Panti Rapih Pasca Gempa (Studi Kasus : Bencana Gempa 27 Mei 2006)

Earthquake disaster on May 27, 2006 has forced many buldings to terminate their service due to the severe damage the earthquake caused to the buildings components. Such damage requires renovation in order to restore the building performance and function. This research analyzed the renovation cost analysis for Panti Rapih Nursing Academy in Sleman Regency, Yogyakarta. This research related to building advisability after shaked by earthquacke based on the Condition Index. Analytical Hierarchy Process (AHP) was used for the analysis. Based on this method, the building Condition Index depends on two parameters. The first parameter is building component and sub component weight. The second is the damage degree and quantity, which was obtained by onsite visual assessment. This research included the analysis of renovation cost completed with factors influencing the cost based on the degree of the damage. The renovation cost was calculated by multiplying unit cost and quantity of works, which was obtained from onsite results of the direct survey. The unit cost used refered to official cost in Regency of Sleman, Yogyakarta. Finally, the result obtained were then compared to the cost computed by contractor. Analysis results showed that the Condition Index of Nursing Academy Building was 93,5394%, which was within low damages category. In theory, the cost to restore the building Condition Index (back to 100%) was Rp. 73.160.000,00. This amount was lower than the real cost of Rp 97.680.000,00 calculated by the contractor. Such difference may be due to the different method used when calculating the quantity and unit cost of works

A(2)B-Miktoarm Glycopolymer Fibers and Their Interactions with Tenocytes

Electrospun biodegradable membranes have attracted great attention for a range of tissue engineering applications. Among them, poly­(ε-caprolactone) (PCL) is one of the most widely used polymers, owing to its well-controlled biocompatibility and biodegradability. However, PCL also has a number of limitations, such as its hydrophobic nature and the lack of functional groups on its side chain, limiting its ability to interact with cells. Herein, we have designed and prepared a series of well-defined A₂B-miktoarm copolymers with PCL and glycopolymer segments to address these limitations. Moreover, copolymers were electrospun to make membranes, which were studied in vitro to investigate cell affinity, toxicity, activity, and adhesion with these materials. The results indicate that incorporating glucose moieties into miktoarm polymers has improved the biocompatibility of the PCL while increasing the cellular interaction with the membrane material

SISTEM PENDUKUNG KEPUTUSAN ALTERNATIF PEMELIHARAAN GEDUNG SEKOLAH (Studi kasus: SLTP Negeri I Pakem)

The performance of the building declines in line with the age of the building. To maintain the performance of the building, the building maintenance should be carried out. For this reason, an adequate program that able to analyze cost as well as condition of the building has been developed in this research. The assessment was carried out in a secondary school building in Pakem Sub Regency of Yogyakarta. The research used Analyzes of Hierarchy Process (AHP). Besides, the maintenance cost was also considered in the analysis. The secondary school has several buildings. Each building consists of structural, architectural and utilities components. This research mainly studied the performance of the architectural components rather than other components. The architectural components consists of classrooms, office rooms and supporting rooms. In every room, architectural element such as ceiling, wall, window, door and floor are subdivided into their accompanying elements. The elements were then weighted in accordance with their functions. The severities of their conditions were assessed in terms of percentage of the deterioration. The residual condition was determined by reducing the index condition (100 is best condition). The accumulative index condition was then represented the condition of every room. The determination of the priority was carried out on the basis of the ratio between increment of the condition (from the existing condition to the best condition) and the cost implied on the maintenance. The priority would go to the highest ratio. An analysis result indicate that among 37 rooms perceived, the class rooms obtained first priority followed by office room and then supporting room. The three first sequence priority among sixteen class rooms are classroom VIIA, the natural science laboratory and classroom IIIA. Among four rooms in office room groups, three first priority are Teacher room, Administration room, Headmaster room, and among seventeen room of supporting room groups, the three first priorities are parking area, canteen room, medical room