High-temperature elastic moduli of thermoelectric SnTe1±x – y SiC nanoparticulate composites

In waste heat recovery applications, thermoelectric (TE) generators are subjected to thermal gradients and thermal transients, creating mechanical stresses in the TE legs. Such stresses are functions of the elastic moduli of the TE material. For SnTe_1±x matrices (where x = 0.0 or 0.016) composite specimens with 0–4 vol% SiC nanoparticle (SiC_NP) additions, the elastic moduli (Young’s modulus, shear modulus, and Poisson’s ratio) were measured by resonant ultrasound spectroscopy from room temperature (RT) to 663 K. The effects of matrix composition and the SiC_NP additions on the RT intercepts and the slopes of the elastic modulus as a function of temperature are also discussed.     

An enterprise modeling and integration framework based on knowledge discovery and data mining

This paper deals with the conceptual design and development of an enterprise modeling and integration framework using knowledge discovery and data mining. First, the paper briefly presents the background and current state-of-the-art of knowledge discovery in databases and data mining systems and projects. Next, enterprise knowledge engineering is dealt with. The paper suggests a novel approach of utilizing existing enterprise reference architectures, integration and modeling frameworks by the introduction of new enterprise views such as mining and knowledge views. An extension and a generic exploration of the information view that already exists within some enterprise models are also proposed. The Zachman Framework for Enterprise Architecture is also outlined versus the existing architectures and the proposed enterprise framework. The main contribution of this paper is the identification and definition of a common knowledge enterprise model which represents an original combination between the previous projects on enterprise architectures and the Object Management Group (OMG) models and standards. The identified common knowledge enterprise model has therefore been designed using the OMG's Model-Driven Architecture (MDA) and Common Warehouse MetaModel (CWM), and it also follows the RM-ODP (ISO/OSI). It has been partially implemented in Java?, Enterprise JavaBeans (EJB) and Corba/IDL. Finally, the advantages and limitations of the proposed enterprise model are outlined.     

A closed loop outsourcing decision model for developing effective manufacturing strategy

The case study deals with aligning production capacity for a US manufacturer of industrial thermal transfer bench-top printer, by exploring various insourcing and outsourcing options based on production, cost and delivery capabilities. A modelling framework is devised which aids in selecting an effective manufacturing strategy that considers key enablers and barriers to successful outsourcing. The proposed model is closed loop, which stresses regular re-evaluation of the existing outsourcing strategy. It models the total product cost for the product currently being manufactured in the US and compares the total costs if it were manufactured offshore in countries such as, Malaysia, China, Slovakia and Mexico. The analysis from the model shows moving manufacturing of the product to Mexico results in the largest business benefit of about $400 savings per unit compared to other countries studied. A closer look at China in the future could be considered as the economic, social and security risks may change enough to warrant re-evaluation of this option. To get a clearer picture of how Mexico rates against Malaysia in the existing state, these risks may be reviewed as an extra data point to finalise the decision to move manufacturing of industrial thermal transfer bench-top printers to Mexico.     

Multi-objective optimization of loading path design in multi-stage tube forming using MOGA

Pre-bending is a critical process required prior to hydroforming. The bending has an effect on the tube thickness and strain which will use up a portion of the formability of the as-received tube. To compensate for this loss of formability, a multi-objective optimization method was applied to improve the hydroforming process after pre-bending. A multi-objective genetic algorithm (MOGA) and Kriging surrogate model were used to optimize the loading path. The Kriging model was used to replace the finite element simulation in constraint handling. The optimal loading parameters in the hydroforming process were obtained for a tube that was previously bent 90°, and showed an improvement in reducing the corner radii of the part at the extrados and intrados of the bend (8.73 mm and 11.24 mm for the extrados and intrados of the bend, respectively). The corresponding corner fill expansion (CFE) was improved by 16.7% (or 1.79 mm) compared to the maximum expansion of 10.73 mm obtained experimentally.     

Design of an apparatus for measuring tool/fabric and fabric/fabric friction of woven-fabric composites during the thermostamping process

The thermostamping of prepreg woven fabrics shows promise as a low-cost high-volume manufacturing process for composite parts. One concern associated with the process is the unwanted formation of defects in the form of fabric wrinkling. This wrinkling can be prevented during the thermostamping process by inducing in-plane forces through the use of one or more metal binder rings. However, if the in-plane forces are too low, then the fabric may wrinkle as the fabric conforms to the shape of the punch, and conversely, if the in-plane forces are too high, then the yarns in the fabric can separate and the fabric may tear and yarns can break. The in-plane forces are a result of the friction between the fabric and the metal binder rings. As the fabric slides over the surfaces of the punch and die, further friction is induced between the metal tooling and the fabric part. In addition, most composite parts consist of multiple layers, and therefore as the fabric is drawn into the die adjacent layers of fabric may slide relative to one another. Thus, the friction at the tool/fabric interface and the interlaminar friction must be understood and quantified to predict part quality as a function of the processing parameters. In this paper, the design and implementation of a load-control test apparatus used to measure the friction between the tool and the fabric and between adjacent layers of fabric during a composite forming process is presented.     

自动生化分析技术的发展及其在临床检验中的应用

近半个世纪以来,各种临床检验技术不断更新,对现代医学的发展影响深远。生化分析作为临床检验的一个主要分支,在灵敏度,准确度以及自动化程度方面都有了很大的提高。尤其随着电子计算机的联合使用,仪器的各种功能性操作,如调零、扫描、控制狭缝、补偿、更换光源和光电转换器、对仪器不正常状态和错误操作报警、数据处理等,都被整合在可调整的操作程序中,这大大提高了检验的自动化程度。近年来,自动生化分析技术在模块化设计和床边检验等方面又取得了长足的进步,进一步扩宽了其应用领域。     

Absorption and twenty‐four‐hour metabolism time‐course of quercetin‐3‐O‐glucoside in rats,in vivo

Rats were meal‐fed a semi‐synthetic diet, with or without quercetin 3‐O‐glucoside (Q3G; 100 mg per meal) and groups of three were killed either fasting, or at 2, 5 and 24 post‐feeding. Flavonoids and their metabolites in the diet, stomach contents, small intestinal lumen and mucosa, caecal contents and plasma were determined by LC/MS. Q3G was not hydrolysed in the stomach, but deglycosylation and further metabolism occurred in the small intestinal mucosa. At least 17 flavonoid glucuronides were identified in the lumen and mucosa, with evidence of time‐dependent changes such as de‐ and re‐glucuronidation. Quercetin mono‐sulphate was also detected in the small intestinal contents. Metabolites were still present in tissue and plasma 24 h after feeding. There was also evidence of complex microbial processing of Q3G in the caecal lumen with the appearance of at least one methylquercetin‐mono‐glucuronide, mono‐sulphate unique to this site in the gut, together with phenolic acid derivatives. Intestinal flavonoid metabolism is thus a very complex process in mammals, involving both enterocytes and bacteria. Copyright © 2004 Society of Chemical Industry     

Long-term fate of a pulse arsenic input to a eutrophic lake

The long-term fate of a 30-year-old pulse arsenic input to a eutrophic lake was studied to determine if As has become effectively trapped in sediments or remains in active exchange with the water column. Legacy As was readily mobilized from sediments of Spy Pond (Arlington, MA), a eutrophic kettle-hole lake that was treated with 1000s kg As in the 1960s to manage excessive aquatic macrophyte growth. Arsenic was mobilized from hypolimnetic sediments during bottom-water anoxia in spring, summer, and fall, and As accumulated to maximum concentrations of 2100 nM. Mobilization of As from epilimnetic sediments was the largest source of As to the water column on a mass basis (145 mol), despite the fact that the epilimnion remains oxic year-round. Sediment cores revealed that surficial sediments contained As at 30-50 times background levels and suggested that there is contemporary As loading to hypolimnetic sediments (590 mol y(-1)). Mass balance estimates indicate that <5% of the contemporary As load comes from external inputs and that the remainder can be explained by mobilization and redistribution of legacy As, both through the water column and by vertical migration of dissolved As within sediments. These findings demonstrate that, decades after As inputs cease, As in contaminated sediments may remain labile and be mobilized to both anoxic and oxic water columns and accumulate to levels near the sediment surface and in the water column that may pose ongoing risks to ecological health.     

Mysterious outbreaks of gastrointestinal illness associated with burritos supplied through school lunch programs

From October 1997 through March 1998, three outbreaks of gastrointestinal illness among school children were linked to company A burritos. In September 1998, a similar outbreak occurred in three North Dakota schools following lunches that included company B burritos. We conducted an investigation to determine the source of the North Dakota outbreak, identify other similar outbreaks, characterize the illness, and gather evidence about the cause. The investigation included epidemiologic analyses, environmental investigation, and laboratory analyses. In North Dakota, a case was defined as nausea, headache, abdominal cramps, vomiting, or diarrhea after lunch on 16 September 1998. Case definitions varied in the other states. In North Dakota, 504 students and staff met the case definition; predominant symptoms were nausea (72%), headache (68%), abdominal cramps (54%), vomiting (24%), and diarrhea (16%). The median incubation period was 35 min and median duration of illness was 6 h. Eating burritos was significantly associated with illness (odds ratio, 2.6; 95% confidence interval, 1.6 to 4.2). We identified 16 outbreaks that occurred in seven states from October 1997 through October 1998, affecting more than 1,900 people who ate burritos from two unrelated companies. All tortillas were made with wheat flour, but the fillings differed, suggesting that tortillas contained the etiologic agent. Results of plant inspections, tracebacks, and laboratory investigations were unrevealing. More than two million pounds of burritos were recalled or held from distribution. The short incubation period, symptoms, and laboratory data suggest that these outbreaks were caused by an undetected toxin or an agent not previously associated with this clinical syndrome. Mass psychogenic illness is an unlikely explanation because of the large number of sites where outbreaks occurred over a short period, the similarity of symptoms, the common food item, the lack of publicity, and the link to only two companies. A network of laboratories that can rapidly identify known and screen for unknown agents in food is a critical part of protecting the food supply against natural and intentional contamination.