SISTEM INFORMASI MONITORING PRAKTEK KERJA INDUSTRI BERBASIS WEB

Penelitian ini bertujuan untuk: (1) mengetahui hasil pengembangan sistem informasi monitoring prakerin berbasis web; (2) mengetahui kevalidan, kepraktisan dan keefektifan sistem informasi monitoring prakerin berbasis web yang dikembangkan. Metode yang digunakan dalam penelitian ini adalah Research and Development (R&D) dengan model pengembangan Waterfall. Penelitian ini dilakukan di SMK Negeri 4 Makassar. Subyek uji coba lapangan dalam penelitian ini berjumlah 30 responden. Pada tahap pengujian sistem dipilih dua validator yang memahami tentang langkah-langkah pengembangan sistem informasi monitoring prakerin. Teknik analisis data menggunakan teknik analisis statistik deskriptif dari perhitungan persentase serta melihat kriteria rentang persentase. Hasil penelitian menunjukkan bahwa: (1) pengembangan sistem informasi monitoring prakerin terdiri dari empat tahap yaitu: analisis, desain, pengembangan/pengkodean dan implementasi/pengujian. Sistem ini memiliki empat pengguna yaitu admin/koordinator prakerin, guru pembimbing, siswa, dan pembimbing industri dengan fitur sesuai dengan hak akses yang dimiliki. Sistem ini memberikan informasi mengenai prakerin secara online. Kegiatan pencatatan data-data prakerin akan dilakukan oleh administrasi prakerin yang nantinya data tersebut akan dikirim dan disimpan pada web; (2) sistem informasi monitoring prakerin berbasis web berada pada kategori sangat valid, sehingga layak digunakan untuk uji coba lapangan terhadap pengguna, kepraktisan dan keefektifan sistem informasi monitoring prakerin berbasis web pada saat uji coba lapangan berada pada kategori sangat praktis dan sangat efektif sehingga layak digunakan dan memberikan manfaat bagi pengguna untuk pengelolaan serta pelaksanaan prakerin di SMKN 4 Makassar. Kata Kunci: Sistem Informasi Monitoring Prakerin, SMK Negeri 4 Makassar, berbasis web

INFLUENCE OF MIXTURE DESIGN, AGE, AND COOLING REGIME ON POSTFIRE MECHANICAL PROPERTIES OF LIGHTWEIGHT SELF-COMPACTED CONCRETE

The post-fire mechanical properties of concrete represent an important set of parameters in the analysis of structural behavior after the occurrence of a fire. In this study, four mixtures of lightweight selfcompacted concrete with different fillers were tested. The tests were conducted by considering the ages of the specimens, which, in this study, were two, three, and five years old. The results show the residual mechanical properties of the specimens after they were heated to target temperatures of 300, 500, and 700 °C. After exposure to high temperature, the specimens were either left to gradually cool until they reached room temperature or rapidly cooled by water. A comparative analysis was conducted on the compressive strength, mass, and dynamic modulus of elasticity of the specimens using the codified residual values given in EN 1994 1-2

Mechanism of vibratory action in the fresh and plastic concrete

Opisan je konstruirani vibracijski reometar koji omogućava kontinuirano zapisivanje ubrzanja klipa aparature koji oscilira u uzorku materijala. Dano je analitičko rješenje osciliranja klipa u pseudoplastičnom fluidu kojim se aproksimira ponašanje plastičnog svježeg betona. Oko svakog zrna stvara se sloj materijala približnih svojstava Newtonovu fluidu, čime se smanjuju otpori preoblikovanju i zbijanju uzorka. Opisano je djelovanje vibracije na plastični beton i slične materijale.The designed oscillatory rheometer, enabling continuous recording of acceleration data for piston oscillating in the sample, is described. An analytical solution for piston oscillation in the pseudoplastic fluid, approximating behavior of the fresh and plastic concrete, is presented. A material coating, with properties similar to those of a Newtonian fluid, forms around every grain and hence reduces sample resistance to remodeling and compaction. The influence of vibratory action on plastic concrete and similar materials is described

Cotton knitted fabric waste as reinforcement in cement screed

Cement screed consists of cement, sharp sand and water, laid as a thin layer over the concrete subfloor. Although the screed is strong, it can be additionally reinforced with fibres, most often polypropylene fibres. In this study, cotton knitted fabric waste (CKFW) was obtained from a local factory producing underwear to reinforce the cement screed. A total of eight mixtures were made: reference mixture, screed reinforced with polypropylene fibres and six mixtures reinforced with CKFW. CKFW was added in 1,25 %, 2,50 % and 5,00 % of the total volume. Before adding to the mixtures, the first CKFW group was saturated with tap water, whereas, the second CKFW group was saturated with dispersion that improves adhesion. The density and air content of the fresh mixtures were tested, and the compressive strength and flexural strength were determined when the specimens were 28 days old. The specific fracture energy is determined based on the curve from the plot of load vs. displacement. The CKFW increases the ductility of cement screeds, although it has no significant effect on the compressive and flexural strength of the specimens. The CKFW that was saturated with tap water achieved better results

UTJECAJ STAROSTI I SKLADIŠTENJA CEMENTA NA NJEGOVU KVALITETU

Cement koji je nepropisno uskladišten nakon godine dana gubi i do 50% svoje čvrstoće. U radu su ispitana svojstva uskladištenih uzoraka cementa starih 30 godina. Radi usporedbe, ispitana su i dva nova cementa: jedan loše uskladišten, a drugi uzet iz tek otvorene vreće. Rezultati ispitivanja uspoređeni su s vrijedećim standardima i referentnim rezultatima iz vremena proizvodnje cemenata

Possibility of cement composite reinforcement by Spanish broom fibres

Danas se u svijetu posvećuje velika pozornost upotrebi celuloznih vlakana u kompozitnim materijalima. Pokušava se pronaći što bolja, ekološki prihvatljiva, jeftinija, obnovljiva i po mogućnosti lokalno dostupna zamjena klasičnim sintetičnim vlaknima. Kvaliteta prirodnih vlakana uvelike ovisi o njihovom porijeklu, načinu dobivanja, sastavu i fizikalnim svojstvima. U radu su dani rezultati ispitavanja mogućnosti upotrebe vlakna samonikle biljke brnistre ubrane na lokalnom području za potrebe ojačanja cementnog morta. Dobiveni rezultati pokazuju da kvaliteta vlakana brnistre ne zaostaje za poznatim vlaknima konoplje i lana.A considerable attention is currently paid worldwide to the use of cellulose fibres in composite materials. Attempts are made to find even better, environmentally more acceptable, less expensive, renewable and, if possible, locally available replacement for traditional synthetic fibres. The quality of natural fibres is greatly dependent on their origin, processing requirement, composition, and physical properties. Results obtained by testing possibilities of using fibres of the wild plant called Spanish broom, collected locally for cement mortar reinforcement, are presented in the paper. The results show that the quality of Spanish broom fibres is not inferior to the quality of known hemp and flax fibres

Mechanism of vibratory action in the fresh and plastic concrete

Opisan je konstruirani vibracijski reometar koji omogućava kontinuirano zapisivanje ubrzanja klipa aparature koji oscilira u uzorku materijala. Dano je analitičko rješenje osciliranja klipa u pseudoplastičnom fluidu kojim se aproksimira ponašanje plastičnog svježeg betona. Oko svakog zrna stvara se sloj materijala približnih svojstava Newtonovu fluidu, čime se smanjuju otpori preoblikovanju i zbijanju uzorka. Opisano je djelovanje vibracije na plastični beton i slične materijale.The designed oscillatory rheometer, enabling continuous recording of acceleration data for piston oscillating in the sample, is described. An analytical solution for piston oscillation in the pseudoplastic fluid, approximating behavior of the fresh and plastic concrete, is presented. A material coating, with properties similar to those of a Newtonian fluid, forms around every grain and hence reduces sample resistance to remodeling and compaction. The influence of vibratory action on plastic concrete and similar materials is described

EFFECT OF FILLER FROM RECYCLED CONSTRUCTION WASTE ON PROPERTIES OF SELF-COMPACTING CONCRETE IN FRESH AND HARDENED STATES

Construction waste is becoming a growing concern in the modern world. Waste recycling reduces the need for landfills and preserves natural resources. This paper investigates the possibility of using construction waste in self-compacting concrete. Fillers of various particle sizes were prepared by grinding several types of waste directly without any sorting or separation. Eighteen mixtures of concrete were prepared by varying the types and proportions of fillers and other additives, and they were tested for workability in fresh state, compressive strength, and dynamic modulus of elasticity after 7 and 28 days of hardening. Eventually, the mixtures were also tested for water absorption. Results indicated that fresh concrete samples did not meet all the requirements of self-compacting concrete, and therefore guidelines were proposed for improving the composition of concrete

Pengembangan Sistem Informasi Monitoring Praktek Kerja Industri Berbasis Web.

Penelitian ini bertujuan untuk: (1) mengetahui hasil pengembangan sistem informasi monitoring prakerin berbasis web; (2) mengetahui kevalidan, kepraktisan dan keefektifan sistem informasi monitoring prakerin berbasis web yang dikembangkan. Metode yang digunakan dalam penelitian ini adalah Research and Development (R&D) dengan model pengembangan Waterfall. Penelitian ini dilakukan di SMK Negeri 4 Makassar. Subyek uji coba lapangan dalam penelitian ini berjumlah 30 responden. Pada tahap pengujian sistem dipilih dua validator yang memahami tentang langkah-langkah pengembangan sistem informasi monitoring prakerin. Teknik analisis data menggunakan teknik analisis statistik deskriptif dari perhitungan persentase serta melihat kriteria rentang persentase. Hasil penelitian menunjukkan bahwa: (1) pengembangan sistem informasi monitoring prakerin terdiri dari empat tahap yaitu: analisis, desain, pengembangan/pengkodean dan implementasi/pengujian. Sistem ini memiliki empat pengguna yaitu admin/koordinator prakerin, guru pembimbing, siswa, dan pembimbing industri dengan fitur sesuai dengan hak akses yang dimiliki. Sistem ini memberikan informasi mengenai prakerin secara online. Kegiatan pencatatan data-data prakerin akan dilakukan oleh administrasi prakerin yang nantinya data tersebut akan dikirim dan disimpan pada web; (2) sistem informasi monitoring prakerin berbasis web berada pada kategori sangat valid, sehingga layak digunakan untuk uji coba lapangan terhadap pengguna, kepraktisan dan keefektifan sistem informasi monitoring prakerin berbasis web pada saat uji coba lapangan berada pada kategori sangat praktis dan sangat efektif sehingga layak digunakan dan memberikan manfaat bagi pengguna untuk pengelolaan serta pelaksanaan prakerin di SMKN 4 Makassar. Kata Kunci: Sistem Informasi Monitoring Prakerin, SMK Negeri 4 Makassar, berbasis web