Synthesis, magnetic properties and microstructure of Ni–Zn ferrite by sol–gel technique

In the study, the Ni–Zn ferrite powder of a Ni0.3Zn0.7Fe2O4 composition was synthesized by sol–gel route using metal acetates at low temperatures. Both the scanning electron microscope and X-ray diffraction analyses of various gel samples heated at different temperatures were used to identify the reaction stages where the amorphous-gel-to-crystalline phase transition occurred. The electrical, magnetic and microstructural properties of the toroidal cores were studied. It was found that the initial permeability increased with a large frequency band (0.1–31.39 MHz) and the magnetic loss was small. The electrical resistivity was higher as compared to the ones which were obtained by the conventional process. Therefore, well–defined polycrystalline microstructure nickel–zinc ferrite and a short processing time of gel preparation have become the major achievements of this study

A comparative study of nickel–zinc ferrites by sol–gel route and solid-state reaction

The properties of ferrites are affected by the microstructural problems which have become the most serious obstacles in obtaining high quality reproducible ferrites. In this study, the nickel–zinc ferrites were prepared via two different methods: the conventional classical ceramic method known as the solid-state reaction, and the newer sol–gel method. The electromagnetic and microstructural properties of both different samples were also discussed. A higher electrical resistivity and controlled initial permeability with a smaller loss were found in the sol–gel samples. Consequently, the homogenous microstructure and the advantages in terms of powder and sample preparations have been discovered by means of sol–gel technique

Kesan kepekatan glukopon 215 csup terhadap saiz dan sifat magnet nanozarah Co-Ni-Cu yang disediakan dengan kaedah elektropengendapan

Nanozarah Co-Ni-Cu telah disediakan dengan kaedah elektropengendapan pada keupayaan pengendapan -925 mV (SCE) menggunakan larutan sulfat (0.018M Co2++ 0.180M Ni2+ + 0.002M Cu2+) yang mengandungi surfaktan Glukopon 215 CSUP dan juga tanpa surfaktan. Kesan kepekatan surfaktan terhadap saiz dan sifat magnet nanozarah Co-Ni-Cu yang terhasil telah dikaji. Analisis morfologi permukaan endapan yang diperoleh dilakukan dengan menggunakan mikroskop elektron imbasan pancaran medan (FESEM) manakala sifat magnetnya diselidiki dengan menggunakan magnetometer getaran sampel (VSM). Nanozarah Co-Ni-Cu yang disediakan daripada larutan yang mengandungi Glukopon 215 CSUP didapati berbentuk sfera dengan saiz berskala nanometer. Saiz zarah paling kecil ialah lebih kurang 50 nm, diperoleh pada kepekatan surfaktan 5 %v, iaitu kepekatan paling tinggi yang dikaji dalam kajian ini. Kepaksaan (Hc) didapati lebih tinggi pada sampel yang disediakan daripada elektrolit yang mengandungi surfaktan berbanding tanpa surfaktan

Preparation of Ni–Zn–Cu ferrite particles by sol–gel technique

Ni–Zn–Cu ferrite powders of Ni0.3Zn0.6Cu0.1Fe2O4 composition were synthesized by sol–gel method at low temperatures. Scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses of various gel samples heated at different temperatures helped in identifying the reaction process and the stages where amorphous-gel-to-crystalline phase transition occurred. The powders were used to make ferrite cores and their microstructure was compared with those obtained by the classic ceramic process. The spinel cubic structure Ni–Zn–Cu ferrite was found to form at the temperature of 700 °C with a calcination time of 4 h. Short processing time of gel preparation, homogeneity and well defined polycrystalline microstructure with small grain size were achieved in this study

Analisis keberkesanan benziltrietilamonium klorida sebagai perencat kakisan bagi perlindungan keluli karbon

Keberkesanan perencatan benziltrietilamonium klorida (BK) terhadap perlindungan kakisan keluli karbon di dalam 1 M asid asetik telah dianalisis dengan menggunakan kaedah ujian kehilangan berat. Matlamat kajian adalah untuk menilai tahap kecekapan perencatan BK berdasarkan perubahan nilai kepekatan perencat berkenaan dan suhu. Analisis kehilangan berat menunjukkan kadar kakisan keluli karbon berjaya dikurangkan dengan penggunaan kepekatan BK yang lebih tinggi dan nilai kecekapan perencatan BK mencapai sehingga 70%. Namun kadar kakisan didapati meningkat selari dengan peningkatan suhu. Analisis termodinamik mendapati perencatan BK berjaya mengurangkan proses pelarutan ion-ion logam melalui pembentukan lapisan filem nipis pada permukaan keluli karbon. Analisis juga menunjukkan sebatian BK berupaya menjerap pada permukaan keluli karbon melalui kedua-dua kaedah penjerapan fizikal dan kimia. Proses penjerapan BK pada permukaan keluli karbon didapati lebih menjurus kepada model isoterma penjerapan Langmuir. Analisis morfologi menggunakan mikroskop imbasan elektron turut mengesahkan berlakunya perencatan BK pada tapak permukaan keluli karbon. Keseluruhan kajian mendapati sebatian BK berupaya melindungi keluli karbon daripada mengalami kakisan di dalam medium asid asetik

Islamic Development Bank (IDB), foreign aid and the challenges for sustainable development in Africa

Foreign aid/development assistance involves the transfer of resources in whatever form from the developed countries or multilateral financial institutions like World Bank, IMF, Islamic Development Bank (IDB) etc. to less developed or developing countries for the purpose of promoting and stimulating their economies for growth and development. Unfortunately, most of these countries, especially the African countries are characterized by multiple problems such as bad leadership and governance, mismanagement and corruption, debt crisis, insufficient and poor infrastructure, chronic poverty etc.; and all these problems have continued to make nonsense of foreign aid’s judicious and optimal utilization and impact on their economies.However, considering the position and role of IDB over the years in the global economic development; this paper examined the developmental activities of IDB in Africa and some of the challenges for sustainable development.In line with the Financial Two Gap Model (Double Deficit Model) and also the Islamic economic principle of Wide Circulation of Wealth, this paper therefore argues that there are a lot of challenges confronting the continent, which the Bank could assist in resolving through its development assistance, especially in the Muslim populated countries i.e. African Muslim Countries (AMCs). Challenges like Human capital development (HCD), poverty alleviation, corruption and mismanagement, infrastructural development, and good governance among others have enormous implications for sustainable development in the continent. And hence, this paper recommends that IDB should give more attention and priority to growth promoting types of foreign aid like program aid, sectoral aid, technical assistance etc. rather than financial aid, which is often squander. Doing this would facilitate the development process and by extension the desire for sustainability in the continent

Effect of natural aging prior to heat treatment on tensile property of Al-1.2Si-0.5Mg-0.25Fe sheet alloy

Good formability, good corrosion resistance and reasonably good strength of the 6XXX series aluminum alloys have made them a good candidate for automotive body applications. In Europe, the high formability of Al alloy, AA6016 has made it the main automotive skin alloy, while in North America, AA6111 is a preferred alloy because of its good final strength and good dent resistance (Burger et al., 1995)

Screening of Morus alba, Citrus litnon and Trigonella foenum-graecum extracts for antimicrobial properties and phytochemical compounds

In the present study, the effect of aqueous and methanol extracts of Trigonella foenum-graecum seed (fenugreek), Citrus limon peel (lemon) and Morus alba foliage (mulberry) against two Gram- negative bacteria, Aeromonas hydrophila and Escherichia coli and two Gram-positive bacteria, Streptococcus agalactiae and Staphylococcus aureus were investigated and the phytochemical compounds of the tested herbal extracts were determined. The results indicated that the aqueous extracts of Trigonella foenum-graecum seed and Citrus limon peel revealed weak antibacterial activity against the bacteria. The methanol extracts of all herbs exhibited stronger antimicrobial activities against the tested pathogens. Among the entire methanol extracts, the Morus alba had the strongest activities. Aeromonas hydrophila was the most sensitive microorganism tested. The phytochemical screening of the plants showed the presence of secondary metabolites such as phenols, volatile oils, tannins, saponins, steroids, flavonoid, terpenoids and alkaloids

Histopathological changes of skin and gills of catfish (Clarias gariepinus) exposed to organophosphate toxicant

The usage of pesticide in the industry will help increase crop yield and meet consumer demand for Malaysia, a country that is undergoing economic revolution through the agricultural. However, the excessive and inappropriateness use of pesticides can affect the environment, water quality and public health. In this experiment, 40 adult African catfish (Clarias gariepinus) were divided and exposed into sublethal concentrations of Malathion (0.8, 1.6 and 3.0 ppm) and a control group for 48 hours. At the end of the study, all fish were sacrificed before skin and gill samples were collected to determine the effect of malathion on the gills and skin. The histopathological lesions in the gills and skin were scored and statistically analysed to compare between group. Histological examination of the gill showed epithelial lifting at secondary lamella, hyperplasia of primary epithelium, fusion of secondary lamella and infiltration of inflammatory cells with peeling and rupture of epithelial cells of secondary lamellae. In the skin, the changes observed were hyperplasia of mucus cell and shrinkage of the club cells after the exposure to malathion. There were significant differences between treatment and control groups. Thus, malathion causes concentration-independent and nonspecific lesions in the gills and skin of African catfish