Phase behavior,density, and crystallization of polyethylene in n‐pentane and in n‐pentane/CO2 at high pressures

The phase behavior and volumetric properties of polyethylene (PE) in solutions of n‐pentane and n‐pentane/CO₂ were studied in a temperature (T) range of 370–440 K at pressures up to 60 MPa. Measurements were conducted with a variable‐volume view‐cell system equipped with optical sensors to monitor the changes in the transmitted light intensity as the P or the T of the system was changed. Lower‐critical‐solution‐temperature‐type behavior was observed for all of the liquid–liquid (L–L) phase boundaries, which shifted to higher pressures in solutions containing CO₂. The solid–fluid (S–F) phase boundaries were investigated over a P range of 8–54 MPa and took place in a narrow T range, from 374 to 378 K in this P interval. The S–F phase boundary showed a unique feature in that the demixing temperatures showed both increasing and decreasing trends with P depending on the P range. This was observed in both the PE/n‐pentane and PE/n‐pentane/CO₂ mixtures. The density of these solutions were measured as a function of P at selected temperatures or as a function of T at selected pressures that corresponded to the paths followed in approaching the phase boundaries (S–F or L–L) starting from a homogeneous one‐phase condition. The data showed a smooth variation of the overall mixture density along these paths. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2201–2209, 2003     

An interdisciplinary heuristic evaluation method for universal building design

This study highlights how heuristic evaluation as a usability evaluation method can feed into current building design practice to conform to universal design principles. It provides a definition of universal usability that is applicable to an architectural design context. It takes the seven universal design principles as a set of heuristics and applies an iterative sequence of heuristic evaluation in a shopping mall, aiming to achieve a cost-effective evaluation process. The evaluation was composed of three consecutive sessions. First, five evaluators from different professions were interviewed regarding the construction drawings in terms of universal design principles. Then, each evaluator was asked to perform the predefined task scenarios. In subsequent interviews, the evaluators were asked to re-analyze the construction drawings. The results showed that heuristic evaluation could successfully integrate universal usability into current building design practice in two ways: (i) it promoted an iterative evaluation process combined with multi-sessions rather than relying on one evaluator and on one evaluation session to find the maximum number of usability problems, and (ii) it highlighted the necessity of an interdisciplinary ad hoc committee regarding the heuristic abilities of each profession. A multi-session and interdisciplinary heuristic evaluation method can save both the project budget and the required time, while ensuring a reduced error rate for the universal usage of the built environments.     

Investigation of Magnetic Properties of Phase Transformations in Copper-Based Alloys

In this study, the magnetic properties of both Cu_85.41Al_9.97Mn_4.62 and Cu_82.41Mn_13.81Al_3.78 (wt%) shape memory alloys were studied. The analysis of the magnetization as a function of applied field and temperature was conducted between ?10 to 10 T magnetic field ranges at constant temperature. Two alloys were examined using ac magnetic susceptibility measurements. The magnetic saturation values at room temperature were found to be approximately 1 and 70 emu/g for Cu_85.41Al_9.97Mn_4.62 (wt%) and Cu_82.41Mn_13.81Al_3.78 (wt%) alloys, respectively. The magnetic saturation and the coercivity values for the CuAlMn alloy are found smaller than those for the CuMnAl alloy. Moreover, from the magnetization curves, the typical ferromagnetic behavior were observed for both alloys. Details of the morphological properties and chemical composition have been examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX), respectively.     

Prioritization methodology of dangerous substances for water quality monitoring with scarce data

Monitoring and control of dangerous substances discharged into receiving waters have attracted more attention lately. Since it is not possible to analyze every single substance, a prioritization methodology is needed for the selection of those to be monitored. Existing well-developed models require significant amount of data for reliable outcomes. This paper presents a methodology to prioritize the dangerous substances having adverse effects on freshwaters in Turkey, where data are scarce. Such a methodology will also serve as a solid model for other countries with limited background data. The adopted methodology enabled the elimination of chemicals to generate a candidate list composed of 608 substances among more than 5000 substances. Further screening and prioritization were conducted using different assessment methods (i.e., Total Hazard Value, Total Impact Value, Combined Monitoring-based, and Modelling-based Priority Setting) to obtain a proposed Final Candidate Specific Pollutants List of 150 dangerous substances. The proposed Candidate National Pollutant List of Turkey was established by combining 45 priority pollutants of the European Union with a list of candidate specific pollutants. According to the outcomes of this study, monitoring and controlling of 195 dangerous substances in freshwaters are recommended. Further detailed studies should be conducted in order to observe the actual levels of these dangerous substances in freshwaters followed by a review of the monitoring list accordingly. Moreover, further revisions might be required in the proposed list due to some possible versatile conditions in terms of sampling points (i.e., change in the location of industries).     

Gold recovery from dilute gold solutions using DEAE-cellulose

The present work investigates gold recovery using DEAE-cellulose, a common biopolymer derivative, from synthetically prepared diluted gold-bearing solutions of 50 ppm. The effects of different recovery parameters on gold recovery efficiency were studied in detail. It was demonstrated that gold recovery efficiency increased with an increasing amount of sorbent, as well as increasing contact time. A gold recovery efficiency of 99% was attained under conditions of 20–40 g DEAE-cellulose per liter at a shaking rate of 130 rpm for 30 min at room temperature. On the other hand, with smaller amounts of sorbent (6 g/l), it was also possible to recover gold from the solution with 99% efficiency when the reaction temperature was increased to 60 °C. The shaking rate and temperature were demonstrated to play a vital role in the recovery process. It was also found that gold recovery by DEAE-cellulose is an intermediate-controlled process with an activation energy of 37.11 kJ/mol. The XRD pattern and SEM images revealed that the recovered gold was in the metallic form.     

A decision support framework for metrics selection in goal-based measurement programs: GQM-DSFMS

Software organizations face challenges in managing and sustaining their measurement programs over time. The complexity of measurement programs increase with exploding number of goals and metrics to collect. At the same time, organizations usually have limited budget and resources for metrics collection. It has been recognized for quite a while that there is the need for prioritizing goals, which then ought to drive the selection of metrics. On the other hand, the dynamic nature of the organizations requires measurement programs to adapt to the changes in the stakeholders, their goals, information needs and priorities. Therefore, it is crucial for organizations to use structured approaches that provide transparency, traceability and guidance in choosing an optimum set of metrics that would address the highest priority information needs considering limited resources. This paper proposes a decision support framework for metrics selection (DSFMS) which is built upon the widely used Goal Question Metric (GQM) approach. The core of the framework includes an iterative goal-based metrics selection process incorporating decision making mechanisms in metrics selection, a pre-defined Attributes/Metrics Repository, and a Traceability Model among GQM elements. We also discuss alternative prioritization and optimization techniques for organizations to tailor the framework according to their needs. The evaluation of the GQM-DSFMS framework was done through a case study in a CMMI Level 3 software company.     

High resolution spherical microwave holography

A practical technique is developed to determine the electric and/or magnetic field on objects and sources inside a spherical measurement surface. The technique, known as spherical microwave holography (SMH), provides a nondestructive, nonintrusive method of point-by-point evaluation of antennas and radomes over their spatial extent. The resolution capability of SMH is developed and demonstrated by measurements. Resolution in SMH is only limited by the measurement system's capabilities. Dielectric and metallic obstacles on the surface of a radome are located and identified. Resolution as small as 0.33λ₀ is demonstrated     

A Benchmark for Some Physical Properties of Zinc-Blende ZnS

Somephysical properties of zinc-blende polytype of ZnS were investigated via geometry optimization calculations. After employing a shell model interatomic potential to our computations, some physical parameters such as typical cubic elastic constants, young modulus, shear modulus, bulk modulus, poisson ratio, elastic wave velocities, static and high frequency dielectric constants, and static refractive index zinc-blende ZnS were deduced. Later, previous theoretical results and our current results with each other as well as with former experimental findings were evaluated. Present results exhibit a fair consistency with experiments and better than those of several recent density functional theory results for the considered parameters of related material.     

Determination of important biochemical properties of honey to discriminate pure and adulterated honey with sucrose (Saccharum officinarum L.) syrup

The aims of the present study were to determine biochemical properties of honey samples and to discriminate pure and adulterated honey produced by the standard bee feeding method (control honey), the shaking method (pure blossom honey), and overfeeding (100 kg/colony syrup) with sucrose syrup (adulterated honey). The biochemical properties evaluated were moisture, ash, acidity, hydroxymethylfurfural (HMF), specific sugars (i.e. fructose, glucose, fructose–glucose, sucrose, and maltose), diastase activity, δ¹³C value (honey), δ¹³C value (protein), electrical conductivity, potassium, vitamin C, and proline. Fifteen honey samples were analyzed by discriminant analysis stepwise method. Proline, electrical conductivity and sucrose were found as discriminative characters of samples. Based on these three properties 100% of original group cases (samples) correctly classified in their real group. We found that the honey produced by feeding with 100 kg sucrose syrup per colony contained the sucrose as low as pure blossom honey. Therefore, the sugar (sucrose, fructose and glucose) content of honey cannot be used to distinguish between adulterated (sucrose syrup) and pure blossom honey.