Characterizing pathological imperfections in macromolecular crystals: lattice disorders and modulations

Macromolecular crystal structure determination can be complicated or brought to a halt by crystal imperfections. These issues motivated us to write up what we affectionately call ‘The Definitive Hitchhiker’s Guide to Pathological Macromolecular Crystals: Lattice Disorders and Modulations’. Perhaps the most challenging imperfections are lattice order–disorder phenomena and positional modulations. Many of these types of crystals have been solved, and progress has been made on the more challenging forms. Diagnostic tools and how to solve many of these problem crystal structures are reviewed. New avenues are provided for approaching the solution of incommensurately modulated crystals. There are a good number of case studies in the literature of lattice order–disorder phenomena and crystallographic modulations that make it timely to write a review. This review concludes with a projected pathway for solving incommensurately modulated crystals, personal views of future directions and needs of the crystallographic community.     

POPS: an off-peak precomputing scheme for privacy-preserving computing

Emerging privacy-preserving technologies help protect sensitive data during application executions. Recently, the secure two-party computing (TPC) scheme has demonstrated its potential, especially for the secure model inference of a deep learning application by protecting both the user input data and the model parameters. Nevertheless, existing TPC protocols incur excessive communications during the program execution, which lengthens the execution time. In this work, we propose the precomputing scheme, POPS, to address the problem, which is done by shifting the required communications from during the execution to the time prior to the execution. Particular, the multiplication triple generation is computed beforehand with POPS to remove the overhead at runtime. We have analyzed the TPC protocols to ensure that the precomputing scheme conforms the existing secure protocols. Our results show that POPS takes a step forward in the secure inference by delivering up to \(20\times \) and \(5\times \) speedups against the prior work for the microbenchmark and the convolutional neural network experiments, respectively.

     

Groundwater problems in surface coal mining in Scotland

The paper reviews the problems encountered with groundwater in surface mining in Scotland. The problems which occur at various stages of the mining process from initial exploration to mine planning and final restoration are referred to. Special consideration is given to mine drainage and pumping methods.     

中等含水层下留设防砂煤柱开采的试验与研究

百善煤矿主采煤层上方直接覆盖有22－27m的砂砾石含水层,严重威胁矿井的安全生产。为了安全合理地开采,进行了矿区水文地质和上覆岩层岩石力学、水理性质以及“两带”高度试验。结果表明：含水层内含黏量较高,垂直渗透能力较弱;所留煤柱属软弱或极软弱类型;风化带内黏土矿物含量较大;吸水后体积膨胀,再生隔水能力强;受采动影响后,具阻水和抑制导水裂隙带继续发展的双重作用;根据以上研究结果,取得了将垂高50m的防水煤柱缩小到12－20m防砂、防塌煤柱的技术突破,安全地多采煤600多万t,经济效益显著。     

凹凸棒石粘土干燥剂的制备与性能研究

本文就利用凹凸棒石粘土制作干燥剂的实验研究作一介绍，通过加入一种或多种改性剂，有效的改善了凹凸棒石粘土的吸湿性能，并且在加入粘结剂制成球形颗粒后仍然能保持较高的吸湿率，吸湿后不变形，具有较高的强度，成本低，无污染，能反复再生使用。     

用氮气和戊基黄药浮选时黄铁矿的低电位疏水状态

为了解释和查明N2TEC浮选法的基本原理，本文报道了在用戊基钾黄药(PAX)作捕收剂时，黄铁矿的低电位疏水状态的研究成果。新制定的N2TEC浮选法的目的是提高难处理含金硫化矿金回收率。在典型的N2TEC浮选法中，用氮气代替空气作为浮选气体，戊基钾黄药作为评选含金黄铁矿颗粒的捕收剂。l997年3月，第一个N2TEC浮选工艺在内华达州Lone Tree矿山浮选厂投产，一直操作至今。根据电化学校制接触角测量结果，研究了黄铁矿的低电位、低pH疏水状态与浮选变量(pH、气相组成、捕收剂浓度和黄铁矿电位)之间的关系。     

Minimierung der Umbauzeiten bei Stahlwerksmodernisierungen am Beispiel eines Stranggießanlagen-Umbaues

In November 2000 the Belgian stainless steel producer UGINE & ALZ Belgium nv, a company of the Arcelor Group, awarded VAI a contract for the upgrading and expansion of their steelmaking plant. The overall project included the revamping and supply of new equipment and systems for the steelmaking, continuous casting and environmental protection facilities. An essential part of this ambitious modernization program was the upgrading and expansion of the existing single-strand slab caster, with an output of 600 000 t/a, to a combined single- or twin-strand slab caster with a nominal production capacity of 1.2 million tons — the world’s largest stainless steel slab caster. All upgrading and installation activities had to be carried out within an extremely tight caster shut-down period of 21 days only in order to minimize production losses. This paper discusses the innovative project management solutions implemented in combination with extensive preassembly activities and workshop testing to assure the successful outcome of this project.     

'EUROPART'. Airborne particles in the indoor environment. A European interdisciplinary review of scientific evidence on associations between exposure to particles in buildings and health effects

The relevance of particle mass, surface area or number concentration as risk indicators for health effects in non-industrial buildings has been assessed by a European interdisciplinary group of researchers (called EUROPART) by reviewing papers identified in Medline, Toxline, and OSH. Studies dealing with dermal effects or cancer or specifically addressing environmental tobacco smoke, house dust-mite, cockroach or animal allergens, microorganisms and pesticides were excluded. A total of 70 papers were reviewed, and eight were identified for the final review: Five experimental studies involving mainly healthy subjects, two cross-sectional office studies and one longitudinal study among elderly on cardiovascular effects. From most studies, no definite conclusions could be drawn. Overall, the group concluded that there is inadequate scientific evidence that airborne, indoor particulate mass or number concentrations can be used as generally applicable risk indicators of health effects in non-industrial buildings and consequently that there is inadequate scientific evidence for establishing limit values or guidelines for particulate mass or number concentrations.     

Treatment of gas-phase methanol in conventional biofilters packed with lava rock

The performance of laboratory scale methanol-degrading biofilters packed with lava rock was checked during almost 1 yr under different conditions. The biomass concentration and biomass adaptation of the inoculum dramatically affected the start-up and the performance of the systems during the first stages of operation. A fast start-up was obtained when using concentrated and adapted inocula, while diluted or non-adapted inocula proved to be much less efficient. The performance of the reactor during long-term operation was significantly affected by the toxic load and moisture content of the gas. Critical loads between 120 and 280 g/m(3)h were reached during different phases of the study. The reactor had a high stability to EBRT changes when working at values between 48.0 and 91.1s, showing little or no negative effect when decreasing the EBRT. Hardly any difference was observed regarding performance when using either a downflow or upflow feed, although slightly better results were obtained when working in a downflow mode.     

An extension of ASM2d including pH calculation

This paper presents an extension of the Activated Sludge Model No. 2d (ASM2d) including a chemical model able to calculate the pH value in biological processes. The developed chemical model incorporates the complete set of chemical species affecting the pH value to ASM2d describing non-equilibrium biochemical processes. It considers the system formed by one aqueous phase, in which biochemical processes take place, and one gaseous phase, and is based on the assumptions of instantaneous chemical equilibrium under liquid phase and kinetically governed mass transport between the liquid and gas phase. The ASM2d enlargement comprises the addition of every component affecting the pH value and an ion-balance for the calculation of the pH value and the dissociation species. The significant pH variations observed in a sequencing batch reactor operated for enhanced biological phosphorus removal were used to verify the capability of the extended model for predicting the dynamics of pH jointly with concentrations of acetic acid and phosphate. A pH inhibition function for polyphosphate accumulating bacteria has also been included in the model to simulate the behaviour observed. Experimental data obtained in four different experiments (with different sludge retention time and influent phosphorus concentrations) were accurately reproduced.