Fluoride bridging modes in fluorozirconate glasses by x-ray and computer simulation studies

A second characteristic ZrZr distance due to edge-sharing (ZrF_n) polyhedra which is observed in crystalline α-ZrF₄ (high temperature form) and is also suggested by recent X-ray studies of BaF₂ZrF₄ glasses, has been observed in ion dynamics computer simulation studies. Experimental X-ray and computer simulation results both imply that about one out of each four bridges between Zr pairs involve two fluoride ions, and that this proportion is almost independent of composition in the binary system.     

Local order scheduling for mixed-model assembly lines in the aircraft manufacturing industry

Multi-variant products to be assembled on mixed-model assembly lines at locations within a production network need to be scheduled locally. Scheduling is a highly complex task especially if it simultaneously covers the assignment of orders, which are product variants to be assembled within a production period, to assembly lines as well as their sequencing on the lines. However, this is required if workers can flexibly fulfill tasks across stations of several lines and, thus, capacity of workers is shared among the lines. As this is the case for final assembly of the Airbus A320 Family, this paper introduces an optimization model for local order scheduling for mixed-model assembly lines covering both assignment to lines as well as sequencing. The model integrates the planning approaches mixed-model sequencing and level scheduling in order to minimize work overload in final assembly and to level material demand with regard to suppliers. The presented model is validated in the industrial application of the final assembly of the Airbus A320 Family. The results demonstrate significant improvement in terms of less work overload and a more even material demand compared to current planning.     

On the use of bubble functions in the local buckling analysis of plate structures by the spline finite strip method

This paper augments bubble functions to the ordinary spline finite strip method in order to calculate the elastic local buckling coefficients of plates and plate structures. The results show that the use of bubble functions improves significantly the convergence of the spline finite strip method in terms of the strip subdivision, and therefore leads to smaller storage requirements for the global stiffness and stability matrices, and faster eigenvalue extraction. Benchmark numerical investigations are presented, including the study of plates with different boundary conditions under uniaxial and biaxial stresses, plates with different aspect ratios under shear, and a stiffened panel under combined shear and compression that has been studied elsewhere. These studies demonstrate that by implementation of the bubble functions, rapid convergence of the solution is obtained. The formulation is ideal for analysing local buckling under a variety of boundary and loading conditions. Copyright © 2000 John Wiley & Sons, Ltd.     

Mathematical modelling of a hydrocyclone for the down-hole oil–water separation (DOWS)

In this study, a mathematical model is developed to predict the efficiency of a down-hole oil–water separation hydrocyclone. In the proposed model, the separation efficiency is determined based on droplet trajectory of a single oil droplet through the continuous-phase. The droplet trajectory model is developed using a Lagrangian approach in which single droplets are traced in the continuous-phase. The droplet trajectory model uses the swirling flow of the continuous-phase to trace the oil droplets. By applying the droplet trajectory, a trial and error approach is used to determine the size of the oil droplet that reaches the reverse flow region, where they can be separated. The required input for the proposed model is hydrocyclone geometry, fluid properties, inlet droplet size distribution and operational conditions at the down hole. The model is capable of predicting the hydrocyclone hydrodynamic flow field, namely, the axial, tangential and radial velocity distributions of the continuous-phase. The model was then applied for some case studies from the field tested DOWS systems which exist in the literature. The results show that the proposed model can predict well the split ratio and separation efficiency of the hydrocyclone. Moreover, the results of the proposed model can be used as a preliminary evaluation for installing a down-hole oil–water separation hydrocyclone system in a producing well.     

Fabrication,Application and Mathematical Modeling of a new Diamine/Trimesoyl Chloride Reverse Osmosis Composite Membrane for Copper Sulfate Desalination from Wastewaters

Excessive amounts of copper ions in the water sources can be harmful to mammals and especially humans. In this study, a new RO composite membrane is fabricated via the interfacial polymerization (IP) reaction of trimesoyl chloride (TMC), piperazine (PZ) and 3,5-diaminobenzoicacid (DABA). The IP reaction was conducted on a polysulfone (PS) layer which acts as a mounting layer for the separation TMC-DABA-PZ layer. The IP reaction time, TMC concentration and transmembrane pressure were the selected study variables. For IP reaction times around 10 s the rejection and flux were equal to 79% and 21.3 L.m^?2.h^?1, respectively, while increasing the IP reaction time to 40 s elevates the rejection and flux to 92% and 27.7 L.m^?2.h^?1, respectively. TMC concentrations around 0.05% w/w demonstrated rejection and flux equal to 88% and 14.3 L.m^?2.h^?1, respectively, while its elevation to 0.2% w/w, increased the rejection and flux to 90% and 17.5 L.m^?2.h^?1, respectively. As with the transmembrane pressure, the optimum pressure was 20 bars, in which the rejection and flux were 95% and 24.07 L.m^?2.h^?1, respectively. Membrane morphology tests are also supporting evidence for these results. The mathematical modeling has also shown that the relation between the concentration, rejection and flux parameters match the resultant data from the conducted experiments. Since both the rejection and the flux of the fabricated membranes have shown great results, such membranes can be used for wastewater treatment at industrial scales.     

Chelate-modified fenton treatment of sulfidic spent caustic

Spent caustic can be treated by several treatment methods. Among the advanced techniques, Fenton reagent has many advantages. But since spent caustic contains excessive amounts of sulfide compounds, utilizing this technique in treatment of such wastewaters is not economical. The acid neutralization step, which was applied as the pretreatment process, showed an 84% COD abatement at temperature equal to 80 °C and a pH equal to 4.0. The acid neutralized wastewater was then introduced to the chelate-modified Fenton system and oxidized. Using a ratio of tartrate/Fe²⁺=1.1, reaction time=50min, temperature=95 °C, Fe²⁺=110mg/l and a ratio of H₂O₂/COD=1.2 in the chelate-modified Fenton system at an optimum pH value equal to 1.9, total COD abatement of the wastewater reached over 99.4%. Having tartrate added to the Fenton system, a series of photochemical reactions enhanced Fe²⁺ and hydroxyl radicals’ generation. This method has proved to be the recommended technique for the contamination abatement of spent caustic.     

N‐Acyl Derivatives of 4‐Phenoxyaniline as Neuroprotective Agents

Neuronal cell death is the main cause behind the progressive loss of brain function in age‐related neurodegenerative disorders such as Alzheimer’s and Parkinson’s diseases. Despite the differing etiologies of these neurological diseases, the underlying neuronal damage is triggered by common mechanisms such as oxidative stress, impaired calcium homeostasis, and disrupted mitochondrial integrity and function. In particular, mitochondrial fragmentation, mitochondrial membrane permeability, and the release of death‐promoting factors into the cytosol have been revealed as the “point of no return” in programmed cell death in neurons. Recent studies revealed a pivotal role for the pro‐apoptotic Bcl‐2‐family protein Bid in models of neuronal cell death, which confirmed Bid as a potential drug target. Herein, we present N‐acyl‐substituted derivatives of 4‐phenoxyaniline that were screened for their potential to attenuate Bid‐mediated neurotoxicity. These compounds provided significant protection against glutamate‐ and Bid‐induced toxicity in cultured neurons. Substitution of the amino group in the 4‐phenoxyaniline scaffold with 4‐piperidine carboxylic acid and N‐hydroxyethyl‐4‐piperidine carboxylic acid yielded compounds that displayed significant neuroprotective activity at concentrations as low as 1 μM . Furthermore, findings of a tBid‐overexpression assay and real‐time measurements of cell impedance support the hypothesis that these compounds indeed address the Bid protein.     

Inhibitory Response to CK II Inhibitor Silmitasertib and CDKs Inhibitor Dinaciclib Is Related to Genetic Differences in Pancreatic Ductal Adenocarcinoma Cell Lines

Casein kinase II (CK2) and cyclin-dependent kinases (CDKs) frequently interact within multiple pathways in pancreatic ductal adenocarcinoma (PDAC). Application of CK2- and CDK-inhibitors have been considered as a therapeutic option, but are currently not part of routine chemotherapy regimens. We investigated ten PDAC cell lines exposed to increasing concentrations of silmitasertib and dinaciclib. Cell proliferation, metabolic activity, biomass, and apoptosis/necrosis were evaluated, and bioinformatic clustering was used to classify cell lines into sensitive groups based on their response to inhibitors. Furthermore, whole exome sequencing (WES) and RNA sequencing (RNA-Seq) was conducted to assess recurrent mutations and the expression profile of inhibitor targets and genes frequently mutated in PDAC, respectively. Dinaciclib and silmitasertib demonstrated pronounced and limited cell line specific effects in cell death induction, respectively. WES revealed no genomic variants causing changes in the primary structure of the corresponding inhibitor target proteins. RNA-Seq demonstrated that the expression of all inhibitor target genes was higher in the PDAC cell lines compared to non-neoplastic pancreatic tissue. The observed differences in PDAC cell line sensitivity to silmitasertib or dinaciclib did not depend on target gene expression or the identified gene variants. For the PDAC hotspot genes kirsten rat sarcoma virus (KRAS) and tumor protein p53 (TP53), three and eight variants were identified, respectively. In conclusion, both inhibitors demonstrated in vitro efficacy on the PDAC cell lines. However, aberrations and expression of inhibitor target genes did not appear to affect the efficacy of the corresponding inhibitors. In addition, specific aberrations in TP53 and KRAS affected the efficacy of both inhibitors.     

酒曲中产酯酵母的筛选及培养条件的研究

采用稀释涂布法从酿酒用曲中筛选到16株产酯能力强、形态各异的酵母菌株,从中优选产酯量最高的1株酵母菌为研究对象,进行产酯条件的研究。通过正交试验,确定较优菌株生长的最适培养条件为温度26℃、pH值为7、培养时间18h、葡萄糖含量为4%（w/v）。对产酯酵母进行耐酒精试验结果表明,最高耐受酒精度为6%vol,有望将其应用到果酒生产中提高果酒品质。