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In seismic areas, the application of structural dampers becomes compulsory in the design of buildings. There are various types of dampers, such as viscous elastic dampers, viscous fluid dampers, friction dampers, tune mass dampers, yielding/ metallic dampers, and magnetic dampers. All damper systems are designed to protect structural integrities, control damages, prevent injuries by absorbing earthquake energy, and reduce deformation. This paper is a part of research investigating the behaviour of the U-shaped steel damper (as one type of metallic damper) that can be applied to the buildings in seismic areas. The dampers are used as connections between the roof and supporting structure, with the two general purposes. The first is to control the displacement of roof under an earthquake, and the second is to absorb seismic energy through the plasticity of some parts in dampers. If a strong earthquake occurs, the plasticity will absorb the seismic energy; therefore, heavy damage could be avoided from the roof’s mainframes. In this paper, several models of U-shaped steel dampers are introduced. Several parameters, such as elastic stiffness, maximum strength, and energy dissipation, are determined under two conditions. Firstly, static analysis of the proposed damper under variation of U-steel plate configurations, searching the model with more significant energy dissipation. Secondly, static analysis of the unsymmetrical and symmetrical damper under different loading directions. An in-house finite element program that involves both geometrical and material nonlinearities is developed as a problem solver. A quasi-static lateral loading is given to each model until one cycle of the hysteresis curve is reached (in the displacement range between -20 mm to +20 mm). The above parameters are calculated from the hysteresis curve. From the results, the behaviour of the U-steel damper can be described as follows. Firstly, increasing the energy dissipation in the lateral direction can be done by increasing the lateral stiffness of the damper. However, it can reduce the maximum elastic deformation of the damper. Secondly, under the random direction of loading, a symmetrical shape can increase the energy dissipation of the damper.

This research proposes a new method for boat impact vibration attenuation using the exchange of momentum principle with a pre-straining spring mechanism. The boat dynamic is modeled using a hinged-supported beam structure. The wave excitation on the boat hull is expressed using one degree of freedom spring-mass system. The simulation study is performed to evaluate the impact damper performance in reducing the boat shock response. Two kinds of momentum exchange impact damper i.e., without and with pre-straining spring mechanism, are evaluated. The simulation results show that the impact damper with pre-straining spring mechanism (PSMEID) is better than the passive momentum exchange impact damper (PMEID) in reducing the boat shock vibration response

The attack of brute force is still one of the popular attacks used to hack into your account unauthorized by a computer system. Brute force is also the most crucial attack and has a high risk of the system being taken over. Investigating brute force attacks is useful for building strong computer network defense systems. In this study, Snort acts as an intrusion prevention system and Cowrie Honeypot as a tool to investigate anomalous behavior that occurs when a brute force attack happened. The aim of this research is to improve Snort's rule signature performance from brute force attacks by relying on the results of the Cowrie Honeypot log investigation. The results obtained, namely Snort rule signature successfully improved detection capabilities with performance in matching the same packet only requires a short processing time, respectively: 3.5 microsecs in Hydra attacks, 3.8 microsecs in Medusa attacks and 2.3 microsecs in Ncrack attacks.

This paper present the conversion of cellulose based on water hyacinth into hydrogel. The water hyacinth cellulose was prepared using acid-alkaline treatment and bleaching. The cellulose properties was optimized by varying the extraction condition such as solvent concentration and temperature. The analysis method of FTIR and XRD were used for characterizing the functional groups and crystallinity of cellulose. The effective condition of extraction were achieved at solvent concentration 17.5% w/w of NaOH, 8% v/v of H2O2 as bleaching agent and temperature of 80°C. The extracted cellulose was used to produced hydrogels using polyvinyl alcohol and glutaraldehyde as crosslinker agent. The research revealed that adding of glutaraldehyde with ratio 1:2 at 25°C give the highest water absorption capacity of 285%.

This research is conducted to determine the natural frequencies of a twisted beam with different orientation of principal axes numerically using Autodesk Inventor. Further, the results are compared experimentally. To simplify in the analysis, the twisted cantilever beam is divided into two segments model. The orientation between two segments is simulated and tested variously. The natural frequencies obtained numerically and experimentally are selected only in transverse vibration based on the simulation of each mode shape of the cantilevered beam. In general, the natural frequencies of the simulated cantilever beam and experiment results tend to similar results.

This paper investigates one type of metallic dampers used in many large buildings in seismic areas. The previous studies have shown a possibility of the introduced damper to act as a damper as well as energy absorber through yielding on some parts of the damper. However, the occurred yielding caused a plastic deformation after unloading. The study aims to substitute the previous critical area to another part which is considerably uncritical during loading. Therefore, an additional part in the form of a slender column is inserted into the damper. The bottom part of the column is clamped to the base plate of the damper. There is a restoring moment acting on the column which was able to restore a large displacement of the damper to at least a small residual plastic displacement after unloading. A stiffness, strength and energy dissipation of the modified damper is determined by a nonlinear finite element technique which involves both geometrically and materially nonlinearities. The model was subjected by a monotonic increasing load which is applied horizontally through the method of displacement control until one cycle of hysteresis is formed. The final result is in a term of comparison of hysteresis curves between a full model of hysteresis damper with and without a slender column.

Myiasis control by means of individual treatment of animals which are mainly rised extensively is time consumed and expensive. The alternative way to control this disease by vaccination is considered effective and economically accepted. However the expected vaccine is now still being developed under a collaborative project between CSIRO, Inter-University Centre on Biotechnology-ITB and Research Institute for Veterinary Science and funded by ACIAR. There are several antigens have been identified as vaccine candidates and an in vitro bioassay technique has been developed for assessing the immunoresponses of vaccine in sheep. Three antigens were used for vaccines in this study, these included protein peritrophic membrane (PM), soluble extract (SE) and pellet extract (PE) of 1st instar larvae of Chrysomya bezziana. Twenty four experimental sheep were divided into 4 groups of 6 animals, 3 groups of animals were injected with PM, SE and PE vaccines with the dose rate of 0.5 g PM/head, 0.8 g PE/head and 4.2 ml LE/head respectively, and the other one group was injected with 4 ml PBS/head as a control group. Vaccination with the same dose was repeated 4 weeks after the 1st vaccination as a booster, and 2 weeks after the booster the sheep were challenged with live larvae, 3 days after challenge animals were killed. Sera were collected at the day of vaccination, 4 weeks after vaccination, 2 weeks after booster, and 3 days after challenge. An in vitro bioassay technique was conducted by culturing 1st instar larvae on five media containing sera collected from each experimental animal. The effects of sera on cultivated larvae were assessed by means of larval weight and larval mortality rate. The results indicated that the growth rate and survival of cultivated larvae in media containing anti-PM sera were significantly lower (P

An “in vivo assay technique” is urgently needed for measuring protective immune effects of a myiasis vaccine in sheep. Such a technique is being developed simultaneously with the development of a vaccine against myiasis caused by the screwworm fly Chrysomya bezziana under a collaborative project undertaken by Balitvet, ITB and CSIRO (Australia) and funded by ACIAR. Experiments were conducted in naive sheep. C. bezziana larvae were allowed to develop on abraded skin in aluminium rings which had been attached to the sheep by means of a glue (Aibon) on the day prior to infection. Rings were arranged on clipped areas close to the mid line of the sheep’s back, two rings on the right side and two rings on the left. Four trials were performed, involving studies on the effects of including wet sponges in the rings to maintain humidity (Trial 1); the effects of sponge and blended meat as counting and transferring media during infection (Trial 2); the effects of the repellants citronella, eucalyptus oil and neem extract in assisting the recovery of larvae (Trial 3); and the effects of the reducing the infective dose from 50 to 25 1st instar larvae/ring and using a fine brush for counting and transferring larvae instead of using a forceps as in the previous groups (Trial 4) on the larval recovery rates (LRR). The results indicated that the inclusion of wet sponges in the rings, the use of sponge and blended meat as counting and transferring media during infection, and the application of repellants all increased the LRR to some extent; however, variations among individual rings remained high. On the other hand, the reduction of infective dose of larvae from 50 to 25 1st instar larvae/ring and using a fine brush for counting and transferring larvae sharply increased the LRR while substantially decreasing the coefficient variations.

Penelitian ini dilakukan untuk mengetahui kecepatan timbulnya berahi dari dosis Gonadotropin Releasing Hormone (GnRH) yang berbeda dan pengaruh waktu pemberian GnRH terhadap jumlah korpus luteum pada sapi Pesisir. Materi yang digunakan yaitu 12 ekor induk sapi Pesisir, hormon PGF 2α dan GnRH. Terdiri dari dua tahap, pertama Induk sapi disinkronisasi dengan 5 ml PGF 2α dan kemudian diberi GnRH 50 µg, 100 µg dan 200µg. Kedua sapi disinkronisasi dengan 5 ml PGF 2α dan kemudian diberi GnRH dosis hasil penelitian tahap pertama dan dibagi atas 4 waktu penyuntikan, yaitu A(16), B(32), C(48), dan D(64) jam. Peubah yang diamati adalah waktu terjadinya estrus setelah diberi dosis yang berbeda dan jumlah korpus luteum (CL) yang terbentuk dari waktu penyuntikan yang berbeda. Pengolahan data dilakukan dengan menggunakan Rancangan Acak Lengkap (RAL). Hasil penelitian menunjukkan bahwa dosis GnRH yang tercepat menunjukan gejala estrus adalah 100 µg dengan rataan 45.42±2.24 jam, 200 µg rataan 51.33±4.51 jam dan 50 µg rataan 76.53±11.92 jam. Waktu pemberian GnRH berpengaruh terhadap jumlah CL yang terlihat dari jumlah CL dari masing-masing perlakuan. Perlakuan C(48) jam menunjukkan jumlah CL yang paling banyak dengan rataan 4.33±1.15 dan diikutiB(32) jam dengan rataan 3.67±1.53,perlakuan A(16) jam dengan rataan1.67±1.15perlakuan D(64) dengan rataan 1.67±0.58.