Use of Lactobacillus paracasei isolated from whey for silver nanocomposite synthesis: Antiradical and antimicrobial properties against selected pathogens

The present research emphasizes the use of safe, inexpensive, and available whey using Lactobacillus paracasei as a source in silver nanocomposite synthesis as an alternative bioactive agent for dairy and biomedical applications. Through the multiinstrumental approach used in this study based on spectroscopic and microscopic methods as well as spectrometric techniques, the characterization and evaluation of silver composites and their antimicrobial and antiradical properties were enabled. Synthesized silver nanocomposites have been found in form of nanocrystals, naturally coated by an organic surface with high antimicrobial and antiradical properties. Furthermore, this work also presents an innovative approach regarding the organic surface (naturally secreted by the bacteria isolated from whey) of the core of nanoparticles, which has already been explored and therefore is starting to supplement the scientific approach concerning biologically synthesized nanoparticles. This work also presents a general frame on the resistance subject by performing the trial interaction of commercially available antibiotics (kanamycin and ampicillin) with new bioactive compounds that can create novel knowledge on complementing their action. Moreover, synthesized silver nanocomposites have shown great antioxidant and antimicrobial effects against various foodborne pathogens from dairy products and drug resistance pathogens found in the medical area to rank on the top of mortality rate.     

Shear analysis of rice husk ash (RHA) reinforced tin-0.7-copper composite solders on electroless nickel/immersion silver (ENIAg) surfaces

In this study, the mechanical performance of the rice husk ash-reinforced tin-0.7 copper composite solder was investigated. 0.01 wt.%, 0.05 wt.% and 0.1 wt.% of rice husk ash (RHA) were added to the solder matrix to prepare the composite solders. In order, to replace the costly electroless nickel immersion gold surface finish on the copper substrate, the effect of electroless nickel immersion silver (ENIAg) as the surface finish was studied. The differential scanning calorimetry (DSC) analysis showed that the composite solder exhibited lower melting temperature relative to the plain solder owing to the inclusion of rice husk ash. Shear strength analysis was carried out to investigate the influence of rice husk ash and electroless nickel immersion silver surface finish on the shear strength of the developed composite solders. The results proved that the rice husk ash failed to enhance the shear strength of tin-0.7 copper lead-free solder with the plain solder exhibiting the highest shear strength.     

粗碲粉加压氧化浸出工艺研究

针对上游工序发生改变，研究了采用加压氧化浸出工艺处理粗碲粉。采用单因素试验考察了液固比、游离碱度、反应压力、反应温度、反应时间对浸出效果的影响，确定最佳工艺条件为：液固比10，游离碱浓度40g/L，反应压力0.8MPa，反应温度75℃，氧化时间2h。试验结果表明碲的浸出率可达95.45％，金银富集在20倍以上。     

宝山西部铅锌银矿床银的赋存状态研究

宝山西部矿床是一个以Ｐｂ，Ｚｎ，Ａｇ为主的多金属矿床，采用光学显微镜，电子探针，Ｘ射线衍射分析和化学分析等方法，研究了银在混合矿和氧化矿两种矿石中的矿物种类，粒度分布及嵌布特征，指出银主要以独立矿物的形式赋存在铅，锌矿物中，方铅矿为银的主要载体矿物。     

金银火法冶炼中炉衬废砖选矿回收金银

金银火法冶炼中炉衬废砖的金银含量高，回收价值大。研究确定了浮－重联合选矿、产品酸浸除镁的炉衬废砖处理工艺。采用组合浮选药剂，可强化浮选效果，浮选尾矿经摇床重选确保了粗粒金银的回收；精矿酸浸除镁可满足冶炼要求；尾矿脱镁后可返回铅粗炼系统综合回收金、银、铜、铋等有价金属，有效地利用了资源。工艺流程简单、合理，易于实施，应用于生产取得了良好的经济效益     

含银废料中银的综合回收和利用工艺方法

综述含银废料中银的综合回收和利用工艺。分析银浸出、银回收和富集、银产品制备的各种工艺方法的特点和适用性。     

碱性直接炼铅法的应用

在比较了几种最新的直接炼铅法的基础上，着重地介绍了碱性直接炼铅法的原理、工艺流程及其特点，并报道了银精矿处理中的应用研究情况。     

用高浓度氰化物直接浸出银精矿

研究了银精矿氰化浸出过程中诸因素与金银浸出率的关系，确定了高氰化物浓度的物合浸出条件。金银的浸出率分别达到９８．９６％和９６．７％。     

提高银铅锌矿伴生银回收率的研究

将分步浮选法代替常规混合浮选方法应用在银铅锌矿中,获得了显著的经济效益。针对各种矿物的不同浮选特性,使银、铅,锌矿物在合理的磨矿细度、捕收剂及各自适宜的pH条件下进行浮选,提高了矿石的品位及回收率,降低了杂质SiO_2含量,并取得了工业试验及投产试车的成功。工业试验的指标是:银、铅、锌的回收率分别为90.67％、85.87％和90.67％,与原选矿厂的工艺流程相比,分别提高了27.67％、12.87％和15.67％,达到了国际先进水平。