Penerapan nilai-nilaimurnidalam kalangan pelajar Sarjana muda pendidikan teknik dan vokasional semasa Menjalankan amali di makmal

Nilai murni ialah nilai yang menjadi asas kepada pembentukan akhlak dan amat penting untuk diserapkan kepada setiap individu khususnya kepada golongan pelajar. Namun demikian menurut kajian-kajian lepas, nilai murni masih kurang diterapkan dengan memuaskan dalam kalangan pelajar terutamanya semasa menjalankan keija amali di makmal. Oleh yang demikian kajian ini dijalankan bagi mengenal pasti sejauh mana pelajar dan pensyarah menerapkan nilai-nilai murni semasa proses pengajaran dan pembelajaran di makmal. Seramai 226 orang pelajar Saijana Muda Pendidikan Teknik dan Vokasional (PTV) menjadi responden dalam kajian ini. Soal selidik merupakan instrumen utama dalam kajian ini di samping temu bual dan pemerhatian sebagai instrumen sokongan. Data-data dikumpulkan dan dianalisis menggunakan perisian SPSS Versi 12.0 bagi mendapatkan min, sisihan piawai dan inferensi ANOVA manakala analisis kandungan bagi data temu bual dan pemerhatian. Dapatan kajian menunjukkan pelajar menerapkan kesemua nilai murni yang terlibat dalam kajian ini. Walau bagaimanapun didapati hanya sebahagian sahaja pensyarah menerapkan nilai-nilai murni kepada pelajar semasa proses pengajaran dan pembelajaran di makmal. Oleh yang demikian, pengkaji mengemukakan beberapa cadangan untuk memastikan pensyarah dan pelajar menerapkan nilai-nilai murni antaranya ialah pihak Universiti Tun Hussein Onn Malaysia (UTHM) perlu membuat penyeliaan dari masa ke semasa bagi memastikan pensyarah dan pelajar bersama-sama menerapkan nilai-nilai murni semasa proses pengajaran dan pembelajaran di makmal

High temperature fatigue characteristics of P/M and hot-forged W-Re and TZM for X-ray target of CT scanner

The fatigue strengths at 1000 °C of layered W-Re/TZM, bulk W-Re and bulk TZM for x-ray target materials were successfully evaluated under load-controlled four-point bending by introducing a fatigue failure criterion as twotimes increase of initial compliance. The obtained fatigue strengths at 1000 °C for layered W-Re/TZM and bulk WRe were similar and 280 MPa and 290 MPa at 106 cycles, respectively, while that of bulk TZM was 200 MPa. During fatigue loading at 1000 °C, dominant fatigue damage would be multiple intergranular crack nucleation and propagation, which would induce the increase of compliance. The reasonability of the fatigue failure criterion was confirmed by the fatigue process observations and the results of room temperature fatigue tests of the specimens tested at 1000 °C up to the cycles corresponding to the fatigue failure criterion

Effect of hardness of second phase particle on fatigue crack growth behavior of steels with hard second phase particle in soft ferrite matrix

ΔK-constant fatigue crack growth (FCG) tests were conducted on low carbon steels with uniformly distributed hard particle with different of pearlite, bainite and martensite in a soft ferrite matrix. The FCG tests by using a single edge cracked tension (SECT) type was performed inside a scanning electron microscope chamber equipped with a servo-hydraulic fatigue machine. During the test, in-situ crack path observation was carried out to identify the crack tip stress shielding phenomena. From the results, influence of hardness of second phase particle on the FCG behavior in Paris regime was systematically investigated. The results revealed that the ferrite-martensite (FM) steel showed significantly higher FCG resistance compared to that of ferrite-pearlite (FP) and ferrite-bainite (FB) steels. The harder second phase particle would be more difficult to be plastically deformed, which would induce higher plastic constrain. This higher plastic constrain may result in significant crack closure effect and stress shielding effect, thereby increasing higher FCG resistance

Effects of size and spacing of uniformly distributed pearlite particles on fatigue crack growth behavior of ferrite–pearlite steels

Fatigue crack growth tests of three ferrite–pearlite steels with different size and spacing of pearlite particles, which were uniformly distributed in the ferrite matrix, were carried out to investigate the effect of microstructure on fatigue crack growth behavior in the Paris regime. The fatigue crack growth rates for the three materials did not coincide with each other, even when the crack growth curves were arranged by the effective stress intensity factor range. From in situ observations, crack tip stress shielding phenomena, such as interlocking and branching, were found on the crack wake, which enhanced fatigue crack growth resistance. A small size and spacing of pearlite particle seemed to induce small but frequent crack deflections, which resulted in crack closure phenomena. On the other hand, the large size of the pearlite particle seemed to induce stress shielding phenomena and, thus, contribute to high crack growth resistance, which was the main reason for the higher fatigue crack growth resistance of the large size and spacing of pearlite particles compared to the small size of pearlite particles

Effect of Loading Frequency on Fatigue Behavior of Magnesium Alloy in Humid Environment

Effect of loading frequency on fatigue behavior of an extruded AZ61 magnesium alloy was investigated at 50? -80%RH environment. The frequencies applied were 1 and 10 Hz. It was found that at stresses below the fatigue limit (at 20? -55%RH), the fatigue fracture was time dependent where fatigue lives for both frequencies were almost identical. In contrast, the fatigue fracture in the region higher than the fatigue limit was dominated by the number of loading cycles. Fatigue fracture at low stress amplitudes for both frequencies were originated from the corrosion pit formed on the surface. Effect of frequency on fatigue crack growth behavior was also investigated. The results showed that in the near-threshold region, the 1 Hz frequency demonstrated higher fatigue crack growth resistance compared to the 10 Hz