Encapsulating peritoneal sclerosis: Importance to the hemodialysis practitioner

Encapsulating peritoneal sclerosis (EPS) is a rare but devastating complication of long-term peritoneal dialysis (PD) therapy. Encapsulating peritoneal sclerosis is characterized by peritoneal membrane inflammation, followed by progressive peritoneal membrane fibrosis and intestinal encapsulation. Clinical manifestations include ascites as well as intermittent and recurrent small bowel obstruction. The prognosis of EPS is poor. The exact cause of EPS remains unknown. While the risk factors for EPS are not well elucidated, EPS is seen with increased frequency after an increased duration of PD therapy. In more than half the patients who develop EPS, the diagnosis is made after transfer to hemodialysis (HD). It is important for the HD practitioner to initiate surveillance in any patient at risk for EPS while maintaining a heightened index of suspicion for EPS in an HD patient with gastrointestinal symptoms and a history of previous PD therapy. Early diagnosis and prompt initiation of treatment is essential. Early in the course of EPS, immunosuppressive therapy remains the mainstay of treatment. Ultimately, parenteral nutritional support may be required along with surgical therapy to relieve intestinal obstruction. We report a case of EPS in an HD patient at our center highlighting the incidence, risk factors, and treatment strategies in the context of available evidence.     

Transportation,handling, and microbial growth performance of molded fiber and expanded polystyrene apple trays

Washington State apples are shipped all over the United States for retail sales. Adequate packaging is needed to minimize apple damage during distribution. Two common materials used for apple trays are expanded polystyrene (EPS) and molded fiber (MF). A recent industry change from MF to EPS trays provoked an interest in exploring the performance difference between the two. Distribution environment hazards include shock, vibration, and compression forces. Prior work has focused only on comparing vibration or shock performance of EPS and MF trays used in protecting apples. In this study, a variety of typical hazards encountered between case pack and retail preparation are considered on a larger sampling scale. The shock, vibration, and interlayer dynamic compressive forces are simulated as well as free‐fall drops possible with manual handling of the cases. A novel device and test method is developed to simulate the forces because of human hands removing trays of apples from the case at retail. Further, a microbial analysis of worst case apple condensation is performed to compare the tray materials effect on apple microbial populations. It is concluded through physical and microbial testing that there is no statistical difference in the physical protection or the growth of microbial populations between EPS and MF apple trays. Most significant tray damage is observed in the EPS trays because of free‐fall drop testing. Apple tray material selection can be shifted to other factors such as cost or consumer preference.     

Development and Application of a Decision Support System for Human Reliability Assessment – A Case Study of an Electric Power Company

This paper describes the human reliability assessment using absolute probability judgment (APJ) method in the Electric Power Company of Serbia (EPS). Taking into account conventional APJ approach, a new decision support tool EPS‐APJ was developed. The EPS‐APJ tool is intended for use by a group of experts for human error probability assessment. The basic goal of the tool is to facilitate the process of decision‐making by experts, in the complex environment of the electric power companies. The usefulness of this new tool is approved in a case study of use of the EPS‐APJ for the purpose of the analysis of a repair intervention on a 10/0.4‐kV steel lattice tower ‘Nogaje’, in the EPS. For the purpose of this study, a database on work‐related injuries, accidents, and critical interventions occurred over a 10‐year period was created. The research comprised analysis of 1074 workplaces, with the total of 3997 employees. The case study performed at the EPS has confirmed that the EPS‐APJ tool for quantification of human errors is highly applicable, comprehensive, and simple to use. Comparison of the results obtained by application of the EPS‐APJ tool versus the basic APJ method has confirmed the accuracy of the decision support tool, and significant speed advantage in conducting an expert evaluation. Copyright © 2015 John Wiley & Sons, Ltd.     

Analysis of the Viscoelastoplastic Behavior of Expanded Polystyrene under Compressive Loading: Experiments and Modeling

The use of expanded polystyrene (EPS) in road paving where the soil exhibits special properties (for example, compressive soil) calls for the necessity of investigating the mechanical behavior of this material. In this work, a study of the EPS compressive behavior is presented. It is divided into two parts: experimental and modeling investigations. The experimental results show that the EPS global compression behavior is characterized by three stages. Analysis of the results shows that the density of EPS plays an important role. A phenomenological mechanical model is considered in order to simulate the EPS viscoelastoplastic behavior in the case of compressive loading. A numerical analysis has been made in order to describe the mechanical behavior of the EPS material. This investigation has revealed a good correlation with the experimental results.     

Spacecraft electrical power subsystem: Failure behavior, reliability, and multi-state failure analyses

This article investigates the degradation and failure behavior of spacecraft electrical power subsystem (EPS) on orbit. First, this work provides updated statistical reliability and multi-state failure analyses of spacecraft EPS and its different constituents, namely the batteries, the power distribution, and the solar arrays. The EPS is shown to suffer from infant mortality and to be a major driver of spacecraft unreliability. Over 25% of all spacecraft failures are the result of EPS failures. As a result, satellite manufacturers may wish to pursue targeted improvement to this subsystem, either through better testing or burn-in procedures, better design or parts selection, or additional redundancy.Second, this work investigates potential differences in the EPS degradation and failure behavior for spacecraft in low earth orbits (LEO) and geosynchronous orbits (GEO). This analysis was motivated by the recognition that the power/load cycles and the space environment are significantly different in LEO and GEO, and as such, they may result in different failure behavior for the EPS in these two types of orbits. The results indicate, and quantify the extent to which, the EPS fails differently in LEO and GEO, both in terms of frequency and severity of failure events. A casual summary of the findings can be stated as follows: the EPS fails less frequently but harder (with fatal consequences to the spacecraft) in LEO than in GEO.     

Harmonic wavelets based statistical linearization for response evolutionary power spectrum determination

A novel harmonic wavelets based statistical linearization approach is proposed for determining the evolutionary power spectrum (EPS) of the response of nonlinear oscillators subject to stochastic excitation. Specifically, first a mathematically rigorous wavelet-based representation of non-stationary stochastic processes is presented. Next, a representation of the process corresponding to a specific scale and translation level is derived. This procedure leads to an EPS estimation approach which is applicable for estimating not only separable but non-separable in time and frequency EPS as well. Several numerical results are presented in this context. Next, focusing on the case of the stochastic response of a linear system and relying on the orthogonality properties of the developed representation an excitation-response EPS relationship is derived. It is further shown that the excitation-response EPS relationship is valid even for linear time-variant (LTV) systems since the approach possesses inherently the element of time-dependence. Further, an extension via statistical linearization of the input-output EPS relationship for the case of a nonlinear system is developed. The approach involves the concept of assigning optimal and response dependent equivalent stiffness and damping elements corresponding to the specific frequency and time bands. This leads to an iterative determination of the EPS of the system response. Pertinent Monte Carlo simulations demonstrate the reliability and versatility of the approach.     

Assessment of technical and environmental performances of wheat‐based foams in thermal packaging applications

This paper presents an assessment of the technical and environmental performance of a wheat‐based foam (WBF) and bio‐composite for shipping chilled products. The thermal conductivity of the WBF was found to be higher than that of polyurethane foams commonly used in high‐value insulation packaging, but close to that of low‐density (expanded polystyrene) EPS foams and significantly lower than that of polyethylene (PE) foams, which are typically used in thermal packaging of foods. The insulation performance of a simple cool box constructed from both the WBF and EPS sandwich panels without the use of any refrigerant was studied experimentally. The comparison demonstrated that the performance of the WBF cool box was comparable to that of the EPS counterpart. Two industrial case studies were conducted on WBF cool boxes with refrigerants in comparison with PE or EPS counterparts. The WBF cool boxes had comparable thermal performance to the EPS and PE counterparts on the basis of identical foam thickness. The performance of the WBF cool boxes was also simulated with finite element (FE) modelling. Good agreement was achieved between experimental data and the FE prediction. The model was then used to assist cool box design. WBF cool boxes made from renewable raw materials are inherently biodegradable and may be used as an alternative to those based on polymer foams in thermal packaging applications. Life‐cycle assessment (LCA) was used to investigate environmental profiles of cool boxes made with WBF, EPS and PE foams. The WBF cool boxes offer substantially lower global warming and abiotic depletion potentials than equivalent cool boxes made from petrochemical foams. Copyright © 2010 John Wiley & Sons, Ltd.     

Biosorption properties of extracellular polymeric substances (EPS) towards Cd, Cu and Pb for different pH values

The aim of this study was to assess the influence of pH on the metal biosorption of extracellular polymeric substances (EPS) extracted from two different activated sludges called A and B. The composition and physico-chemical characteristics of EPS were determined. The biosorption capacities of the EPS were examined at pH 4, 6, 7 and 8 successively with three metals Cu, Pb and Cd using differential pulse polarography (DPP) as an investigation tool and Ruzic's model was used to produce polarographic titration curves. Two apparent pKa were obtained, the first were 6.6 (EPS A) and 5.7 (EPS B), attributed to carboxylic and phosphoric groups whereas the second was 8.7 for EPS A and 9.4 for B and these were attributed to phenolic and amino functional groups. Whatever the EPS and the metal considered, the conditional binding constant did not show significant differences in the strength of complex formed between the EPS and metals. But for all metals, the number of EPS binding sites was significantly lowered by a decrease in the pH of the medium. At pH 4, the metal biosorption capacity of EPS is very low. At pH 6, the number of EPS binding sites increased in the following order: Pb>Cu>Cd whereas at pH 7 and 8, this order changed and was: Cu>Pb>Cd. Simulations of the speciation states of Cu, Pb and Cd at the different pH values in ultra-pure water (25 degrees C, ionic strength 0.045 M) were performed with MINEQL 4.5 software and indicated the presence of hydroxylated forms and sometimes solid forms for Pb and Cu. But the polarographic titration curves revealed precipitation of Cu only at the end of the experiments at pH 8.     

Low O2 Master Bag for Beef Patties: Effects of Primary Package Permeability and Structure

The contribution of the structure and permeability of case‐ready units on the colour changes of ground beef patties during low O₂ storage in master bags, aerobic blooming and display life was investigated. We selected the following case‐ready solutions: PVC 8000 + closed‐cell expanded polystyrene (EPS) tray, PVC 20000 + closed‐cell EPS tray, linear low‐density polyethylene (LLDPE) 26000 + closed‐cell EPS tray and PVC 20000 + open‐cell EPS tray. Patties packaged onto a closed‐cell tray and wrapped with PVC 20000, but never stored in master bag, were taken as a control. We monitored oxygen depletion in the headspace of the master bags, the microbiological indexes and the appearance of the patties (colorimetric measurements and scanning images). During the storage in master bags, the use of a very high permeability wrapping film and an open‐cell EPS tray allowed the best colour stability of the bottom and upper sides of patties through 7 days. After master bag opening, the same combination of materials favoured the blooming of the upper surface pigments of the product and the stability of the oxygenated pigments during the display life. Moreover, the open‐cell trays helped in reducing the discolouration of the bottom side of patties. Hence, this low O₂ master bag system can enhance the colour stability of ground beef patties and therefore extend their distribution life. Copyright © 2013 John Wiley & Sons, Ltd.     

密度和应变率对聚苯乙烯泡沫(EPS)准静态压缩力学行为的影响

分别研究了聚苯乙烯泡沫(Expanded polystyrene,简称EPS)在三种不同密度和三种不同加载速率下的无侧限单轴准静态压缩力学行为.结果表明:EPS的压缩与一般多孔材料的压缩特征相似,其应力-应变曲线也分为三阶段(弹性段、塑性屈服平台段及致密段).并验证了聚苯乙烯泡沫(EPS)在线弹性阶段的弹性模量与其密度近似符合二次函数关系;通过对实验结果的拟合得出了EPS的密度与其屈服强度呈线性关系并给出了关系表达式.同时表明:同一密度的EPS在不同加载速率下其线弹性模量基本不变而屈服强度随加载速率的增加而显著增加,其应变率敏感度m值较大且变化显著,EPS表现出明显的应变率效应.     

纤维聚苯乙烯泡沫颗粒轻质土的制备及力学性能

为促进轻质土在岩土工程中的广泛应用,添加改性聚丙烯纤维改善其力学性能,通过无侧限抗压强度试验分析探讨了纤维聚苯乙烯泡沫（EPS）颗粒轻质土强度-变形特性、受压破坏模式和无侧限抗压强度的影响因素,并运用SEM从微观层次上分析了其力学机制。结果表明:不同EPS颗粒、纤维及水泥掺量时,纤维EPS颗粒轻质土的应力-应变曲线不同;EPS和水泥掺量是强度的主要影响因素,其次为纤维掺量;强度随EPS掺量的增大而显著降低,随水泥掺量增大而显著提高;未加纤维的EPS颗粒轻质土松散且易破碎,强度骤然丧失;添加纤维能提高轻质土的峰值强度、残余强度、整体性和韧性,改善其脆性破坏模式;但EPS掺量较高（大于干土质量的3%）时,纤维与水泥土粘结有限,EPS颗粒轻质土力学性能改善效果较弱;EPS颗粒为空心蜂巢结构,纤维表面布满针状的水泥水化物并形成空间网状结构。所得结论表明纤维改善了轻质土力学性能。      

Effect of polystyrene aggregate size on strength and moisture migration characteristics of lightweight concrete

The aim of this study is to investigate the effect of polystyrene aggregate size on strength and moisture migration characteristics of lightweight concrete. The present study covers the use of expanded polystyrene (EPS) and un-expanded polystyrene (UEPS) beads as lightweight aggregate in concretes that contain fly ash as a supplementary cementitious material. Lightweight concrete with wide range of concrete densities (1000–1900 kg/m³) were studied mainly for compressive strength, split tensile strength, moisture migration and absorption. The results indicate that for comparable aggregate size and concrete density, concrete with UEPS aggregate exhibited 70% higher compressive strength than EPS aggregate. EPS aggregate concrete with small EPS aggregates showed higher compressive strength and the increase in compressive strength was more pronounced in low density concrete when compared with high density concrete. The UEPS aggregate concrete exhibited brittle failure similar to normal weight concrete (NWC), whereas, gradual failure was observed in EPS concrete. Moreover, the moisture migration and absorption results indicate that the EPS concrete containing bigger size and higher volumes of EPS aggregate show higher moisture migration and absorption.     

Multicomponent model of deformation and detachment of a biofilm under fluid flow

A novel biofilm model is described which systemically couples bacteria, extracellular polymeric substances (EPS) and solvent phases in biofilm. This enables the study of contributions of rheology of individual phases to deformation of biofilm in response to fluid flow as well as interactions between different phases. The model, which is based on first and second laws of thermodynamics, is derived using an energetic variational approach and phase-field method. Phase-field coupling is used to model structural changes of a biofilm. A newly developed unconditionally energy-stable numerical splitting scheme is implemented for computing the numerical solution of the model efficiently. Model simulations predict biofilm cohesive failure for the flow velocity between and m s⁻¹ which is consistent with experiments. Simulations predict biofilm deformation resulting in the formation of streamers for EPS exhibiting a viscous-dominated mechanical response and the viscosity of EPS being less than . Higher EPS viscosity provides biofilm with greater resistance to deformation and to removal by the flow. Moreover, simulations show that higher EPS elasticity yields the formation of streamers with complex geometries that are more prone to detachment. These model predictions are shown to be in qualitative agreement with experimental observations.     

基于随机骨料模型的EPS混凝土粒子尺寸效应分析

建立基于随机分布的EPS混凝土细观力学模型,对EPS混凝土的受压损伤破坏过程进行数值模拟,分析EPS混凝土的损伤破坏过程。研究表明,EPS混凝土的损伤破坏有两种形态,即延性破坏和脆性破坏。延性破坏与EPS颗粒的面积占有率、断裂过程区长度有关;脆性破坏与EPS颗粒的面积占有率、粒径大小以及颗粒间距有关。在EPS颗粒面积占有率较低的情况下,EPS混凝土的粒子尺寸效应对混凝土力学性能的影响较明显,在较高面积占有率的情况下,粒子尺寸效应对其影响较小。随着EPS颗粒面积占有率的增加,EPS混凝土损伤破坏由脆性破坏向延性破坏转变。建立基于损伤力学与断裂力学的粒子尺寸效应数学模型,用数值模拟进行验证,发现两者吻合较好。     

Gustatory sweating recurring on peritoneal dialysis but resolving during periods of hemodialysis

Gustatory sweating is a rare disorder characterized by profuse sweating on the forehead, face, scalp, and neck occurring soon after ingesting food, which has been reported in diabetic patients. The mechanism is thought to be triggered by taste buds and not gastric stimulation. We report a case where gustatory sweating repeatedly developed on peritoneal dialysis that resolved on periods of hemodialysis. A 32-year-old woman with diabetic end-stage renal disease developed gustatory sweating shortly after beginning continuous ambulatory peritoneal dialysis despite excellent clearances. After 5 months, she changed to hemodialysis for 2 months and noticed complete resolution of her gustatory sweating; however, after her return to peritoneal dialysis 2 months later, her gustatory sweating recurred. While on peritoneal dialysis, she was treated with clonidine, which resulted in improvement but not resolution of her symptoms as had occurred on hemodialysis. Another period on hemodialysis resulted in the resolution of her symptoms that returned again after restarting peritoneal dialysis. Clonidine provided incomplete relief while topical glycopyrrolate was effective and without complications. We report recurrent gustatory sweating on peritoneal dialysis that resolved with hemodialysis. We have no data to suggest that intra-abdominal stimulation played a role, but rather that despite excellent clearances neuropathy may have played a role. Treatment with topical glycopyrrolate may be safe and effective given every third day if clonidine is ineffective.     

Effect of extraction method on EPS from activated sludge: an HPSEC investigation

The extracellular polymeric substances (EPS) contained in activated sludge flocs resulting from two-sewage treatment plants were extracted according to eight methods referred to in the bibliography. Extracted EPS were characterized by their extraction yield, carbon concentration, their biochemical composition, their HPSEC chromatograms and, where possible, molecular weight (MW) distributions. With HPSEC chromatograms, the use of the mobile phase containing methanol allowed a hydrophobic mechanism for EPS, extracted partly by chemical methods, to be identified. An MW distribution (from 0.1 to 600kDa) was established for EPS extracted by control and physical methods only, from calibration. Except for the resin and heating extraction methods, the EPS extracted from the two sludges displayed the same trend in their HPSEC fingerprints but not in their MW distribution. Results show that the extraction methods using chemical reagents strongly affected the HPSEC fingerprints of EPS, whereas, the physical methods influenced only MW distribution but not HPSEC fingerprints. The use of heat to extract EPS seems to induce hydrolysis of a part of EPS. The HPSEC fingerprint is a good indicator for the appreciation of the consequences of EPS extraction methods on the EPS extracted and the distribution of EPS with low MW in particular.     

EPO泡沫的静态压缩性能及其与EPS和EPE泡沫的比较

对EPO(发泡聚烯烃)、EPS和EPE泡沫进行截面泡孔结构、静态压缩试验以及使用性能比较。应力-应变曲线分析表明,EPO泡沫变形分为弹性段、塑性屈服平台段及致密段;由3者截面泡孔结构、应力-应变关系和缓冲系数-静应力关系的比较表明,EPO静态缓冲性能介于EPS与EPE之间,但与EPS更为接近;使用性能比较表明,EPO泡沫衬垫避免了EPS和EPE的缺点,集合了EPE柔软性、反复冲击性能好和EPS可模制成型的优点。     

pH对膜污染层EPS污染特征的影响及机理分析

溶液pH值不仅影响溶质的电荷等表面性质,同时也影响膜表面的特性,从而影响溶质与膜表面之间的相互作用和溶质在膜面的沉积量及膜通量.胞外多糖(Extracellular POlvsac-charides,EPS)是膜生物反应器(Membrane Bioreactor,MBR)中主要的膜污染物质之一,从实际MBR膜污染层中分离纯化得到的EPS,在EPS引起膜污染机理分析的基础上,以过滤阻力、EPS在膜表面沉积量及膜通量为评价指标,综合分析不同溶液pH对EPS污染特征的影响,可为揭示MBR中EPS膜污染的成因和机理以及污染膜的清洗提供参考.结果表明,MBR膜污染层EPS的膜污染过程较好地符合沉积阻力模型,EPS在膜表面的污染主要是EPS沉积引起的;EPS溶液的pH越高,其与膜之间的排斥力越大,沉积量越少,沉积阻力越小,膜通量越高.pH为7.0时,沉积阻力为3.34×10~(11) m~(-1),沉积量为1.25 g/m~2,初始相对膜通量为9.8%.     

冲击荷载作用下EPS混凝土动态性能研究

配置聚苯乙烯(Expanded Polystyrene,EPS)颗粒体积掺量分别为10%,20%,30%,40%,50%的EPS混凝土,采用Φ100 mm分离式霍普金森压杆(SHPB)试验装置,以动态抗压强度和临界应变为指标,研究EPS混凝土在冲击荷载作用下的动态性能,探索EPS颗粒对混凝土动态性能的改善机理。结果表明:由于应变率效应,相同体积掺量的EPS混凝土动态抗压强度与临界应变随应变率的增加而提高,具有显著的应变率相关性;以临界应变为变形性能指标,由于EPS颗粒的微结构效应,在EPS颗粒体积掺量0～40%范围内,其变形性能随EPS体积掺量的增加而提高,当EPS颗粒体积掺量达到50%时,其变形能力有所降低。EPS颗粒体积掺量为40%时对混凝土变形性能的改善效果最佳。