Effect of Modification on the Physicochemical and ThermalProperties of Organophilic Clay Modified with Octadecylamine
Organophilic clay was modified by ion exchange reactions using Octadecylamine. The reaction process was carried out at a temperature of 70oC for 90 minutes reaction time in a batch reactor equipped with a mechanical stirrer rotating at a speed of 300 rpm. Physicochemical and thermal 
properties of the clay before and after modification were determined and compared using Field Emission Scanning Electron Microscope/ Energy Dispersive X-ray spectroscopy (FESEM/EDX),Fourier transform infrared spectroscopy (FT-IR) and Thermogravimetric Analyzer (TGA). FESEM images show clearly the micro structural differences between the modified and unmodified clay while EDX shows a compositional changes between modified and unmodified 
clay with the presence of 7.27% carbon in the modified clay. The analysis of FT-IR spectra shows the attachment of some functional groups which are mostly alkyl and hallo-alkyl groups. This is an indication of proper modification. TGA plots of both pure unmodified and organically modified clay attained stability at a temperature between 500oC and 900oC after reduction in weight due to evaporation of moisture and decomposition of the adhered Alkylammonium salts between 30oC and 500oC. This confirmed that thermal stability of the organically modified clay compared favorably with pure natural clay under TGA.
Solving Environmental Problems with Latvian Clay-Based Sorbents
Currently there is an increasing interest in application of natural clay minerals in production of various products, including sorbents for waste water treatment. For practical application of clay as a sorbent, it is significant not only to establish its properties, but also to be able to modify them. Only during the last twenty years, an increasing effort has been directed to systematic studies of clay sorption properties. A special attention has been devoted to improvement of clay sorption properties, which could allow to scientifically develop various sorbents for collection of oil products, such as oil spills from water surface, water processing and cleaning of waste waters from heavy metal ions, organic and inorganic admixtures, etc. In this study, surface properties of Latvian Triassic (Vadakste deposit) smectite-containing clay samples were examined, in order to develop cheap, clay-based sorbents of high quality. Using sedimentation method, the granulometric composition of natural clay samples was determined. Surface morphology of the obtained samples was studied by using scanning electron microscopy. Sorption properties of natural Vadakste deposit clay samples were modified by thermal treatment, as well as by adding a natural modifier based on hemicellulose and lignin (HLS). This type of clay modification has almost never been used in practice. Optimal thermal treatment conditions and HLS modification conditions were determined for the natural clay samples. It was found that water absorption decreased with increasing the thermal treatment temperature from 300 to 500 and 800 °C, however silicone oil and rapeseed oil absorption doubled at the same time. After adding HLS to clays within the range of 0.053% to 0.13%, both water and oil absorption doubled. The ability of natural and modified clay samples to adsorb copper and zinc ions from the corresponding salt solutions was investigated. The obtained results proved that the developed clay-based sorbent granules can be used for removal of copper and zinc ions from waste water, for collection of oil and oily substances; and as a cheap, environmentally safe pet litter. Darbā pētītas Latvijas triasa mālu (Vadakstes atradne) paraugu virsmas īpašības ar mērķi izstrādāt lētus un kvalitatīvus sorbentus uz šo mālu bāzes. Noteikti dabīgo mālu paraugu optimālie termiskās apstrādes un modificēšanas apstākļi ar dabīgo modifikatoru uz hemiceluložu un lignīna bāzes (HLS). Šāda veida mālu modificēšana agrāk praktiski nav lietota. Pētīta termiskās apstrādes ietekme uz dabīgo un ar HLS modificēto mālu granulām. Noskaidrots, ka, palielinot termiskās apstrādes temperatūru robežās no 300 līdz 800 °C, mālu paraugu ūdens saistītspēja samazinājās, tai pašā laikā silikona eļļas un rapšu eļļas sorbcija palielinājās 2 reizes. Pievienojot māliem no 0,053% līdz 0,13% HLS, gan ūdens, gan eļļas sorbcija palielinājās divas reizes. Pētīta dabīgo un modificēto mālu paraugu smago metālu jonu sorbcijas spēja. Izpētīta mālu paraugu spēja adsorbēt vara un cinka jonus no to sāļu šķīdumiem. Iegūtie rezultāti liecināja, ka uz mālu bāzes radītās sorbcijas granulas var tikt izmantotas notekūdeņu attīrīšanai no vara un cinka joniem, eļļu un eļļu saturošo materiālu savākšanai no akvatoriju virsmas.
Failure analysis for poor solderability of Au surface of PCB
Nonwetting is one of the common problems and is always rejected in electronic assemblies. ENIG pads of a PCBA exhibited nonwetting after lead-free reflow soldering. With the aid of stereomicroscope, SEM&EDS and XRF, a series of analysis was performed. And after visual inspection, surface and cross section analysis, thickness measurement and solderability test, it can be inferred that oxidation of plating surface was the main reason for nonwetting, and corrosion in Ni plating caused an adverse impact on solderalibity.