Investigating the effects of draw ratio,hot-pin temperature,and overfeeding on the color values of air-jet textured polyester yarns

In this study, influence of draw ratio, hot-pin temperature, and overfeeding on the color values of air-jet textured yarns, which were produced from polyester partially oriented yarn, was investigated. Two different air-jet textured yarns were produced by setting the value of only one variable to its minimum and maximum, while the reference values selected for the production of the reference yarn were used for the rest of the variables. Six different air-jet textured yarns, which were produced by varying draw ratio, hot-pin temperature, and overfeeding, and the reference air-jet textured yarn were dyed with the same dyeing procedure. Some physical properties such as linear density, tenacity, and breaking extension of the air-jet textured yarns were measured and images of the cross-section of the yarns were taken. The color coordinates of the dyed yarn samples were also measured. The color differences of six yarn samples compared to reference air-jet textured yarn were calculated. Changing draw ratio, hot-pin temperature, and overfeeding affected the color values of the air-jet textured yarns according to the results. It was found that, overfeeding is the parameter that affects the color values of the air-jet textured yarn most.     

A hierarchical classification scheme to define and order the design space for integral snap-fit assembly

The diversity of integral attachment snap-fit feature types (e.g. cantilever hooks, bayonet-fingers, compressive hooks, annular snaps, and others), and their possible combinations, sizes and locations and orientations on parts to enable assembly has made it appear that design possibilities may be unbounded. Attempts at understanding, no less optimization, seemed intractable. This paper presents a hierarchical classification scheme that brings order to the design space, and uses that classification scheme to define boundaries and size of the design space for achieving attachment at a level above feature detailing. Classification is based on the essential geometry of parts being assembled. The result is surprising order and simplicity, and the ability to reduce viable options for any assembly situation to a number (e.g. 8–10) that will permit true optimization.     

Budgeting Owner’s Construction Contingency

This paper attempts to find ways to reduce an owner’s construction contingency budget such that just enough contingency is allocated that will allow the owner to deal with uncertainties but at the same time not tie up valuable funds that can be used for other activities. It is suggested that the common practice of allocating a fixed owner contingency (e.g., 10% of the contract value) to all projects contracted out by an owner is not appropriate. Instead, a methodology is proposed whereby the owner (1) analyzes historical project data; (2) identifies the line items that are problematic; (3) takes the necessary measures at the preconstruction stage to streamline these line items with respect to site conditions, time constraints, constructability issues, and project scope; and (4) finally budgets contingency funds based on this information. A case study was conducted to analyze the contingencies budgeted and actually spent by an owner in nine parking lot projects. The findings indicated that a systematic approach such as the methodology proposed in this paper is likely to minimize the owner’s contingency budget.     

Adopters and non-adopters of internet stock trading in Singapore

This study examines the attitudes of adopters and non-adopters toward Internet stock trading in Singapore. Data were collected using a web-based questionnaire survey. Usable responses totaled 208 for adopters and 222 for non-adopters. This study examines the demographic profiles of adopters and non-adopters, stock trading frequency, and preferred stock trading method. It also examines the attitudes towards Internet stock trading in terms of security, economics of cost, importance of investment services, willingness to pay for financial services, percentage of stock trades transacted through the Internet, and change in trading behaviour due to the Internet. Implications of the results are discussed.     

Multi-Objective Evolutionary Algorithm Based on Decomposition for Energy Efficient Coverage in Wireless Sensor Networks

Wireless sensor networks (WSNs) have become a hot area of research in recent years due to the realization of their ability in myriad applications including military surveillance, facility monitoring, target detection, and health care applications. However, many WSN design problems involve tradeoffs between multiple conflicting optimization objectives such as coverage preservation and energy conservation. Many of the existing sensor network design approaches, however, generally focus on a single optimization objective. For example, while both energy conservation in a cluster-based WSNs and coverage-maintenance protocols have been extensively studied in the past, these have not been integrated in a multi-objective optimization manner. This paper employs a recently developed multi-objective optimization algorithm, the so-called multi-objective evolutionary algorithm based on decomposition (MOEA/D) to solve simultaneously the coverage preservation and energy conservation design problems in cluster-based WSNs. The performance of the proposed approach, in terms of coverage and network lifetime is compared with a state-of-the-art evolutionary approach called NSGA II. Under the same environments, simulation results on different network topologies reveal that MOEA/D provides a feasible approach for extending the network lifetime while preserving more coverage area.     

Effect of Some Chemicals on Thermal Conductivity of Impregnated Laminated Veneer Lumbers Bonded with Poly(vinyl acetate) and Melamine–Formaldehyde Adhesives

Thermal conductivity is a very important parameter in determining heat transfer rate and is required for the development of drying models and for the industrial operations such as adhesive cure rate. The objective of this research was to investigate the effects of impregnation on the thermal conductivity of six-layered laminated veneer lumber (LVL) made of beech and pine. Boric acid, zinc chloride, and ammonium sulfate were used as impregnation chemicals and poly(vinyl acetate) (PVAc) and melamine-formaldehyde (MF) adhesives as bonding agent were used to produce LVLs. The veneers were impregnated by using the vacuum-pressure method. The thermal conductivity test was performed based on ASTM C 1113-99 hot-wire method. Results showed that the impregnation chemicals increase the thermal conductivity. As impregnation chemicals the highest values were obtained with boric acid and zinc chloride. In addition, the thermal conductivity of LVL made of beech was higher than that of LVL made of pine. The thermal conductivity of LVL bonded with PVAc was absolutely higher than LVL bonded with MF in both wood species.     

A sub-1 Volt 10-bit supply boosted SAR ADC design in standard CMOS

This paper presents a new very low-power, low-voltage successive approximation analog to digital converter (SAR ADC) design based on supply boosting technique. The supply boosting technique (SBT) and supply boosted (SB) circuits including level shifter, comparator, and supporting electronics are described. Supply boosting provides wide input common mode range and sub-1 Volt operation for the circuits designed in standard CMOS processes that have only high-V_t MOSFETs. A 10-bit supply boosted SAR ADC was designed and fabricated in a standard 0.5 μm, 5 V, 2P3M, CMOS process in which threshold voltages of NMOS and PMOS devices are +0.8 and −0.9 V, respectively. Fabricated SB-SAR ADC achieves effective number of bits (ENOB) of 8.04, power consumption of 147 nW with sampling rate of 1.0 KS/s on 1 Volt supply. Measured figure of merit (FOM) was 280 fJ/conversion-step. Proposed supply boosting technique improves input common mode range of both SB comparator and SAR ADC, allows sub-1 Volt operation when threshold voltages are in the order of the supply voltage, and achieves low energy operation. Thus, SBT is suitable for mixed-signal circuit designed for energy limited applications and systems in where supply voltage is in the order of threshold voltages of the process.     

Reactive synthesis with maximum realizability of linear temporal logic specifications

Acta Informatica - A challenging problem for autonomous systems is to synthesize a reactive controller that conforms to a set of given correctness properties. Linear temporal logic (LTL) provides a...     

Uncertainty quantification via codimension‐one partitioning

We consider uncertainty quantification in the context of certification, i.e. showing that the probability of some ‘failure’ event is acceptably small. In this paper, we derive a new method for rigorous uncertainty quantification and conservative certification by combining McDiarmid's inequality with input domain partitioning and a new concentration‐of‐measure inequality. We show that arbitrarily sharp upper bounds on the probability of failure can be obtained by partitioning the input parameter space appropriately; in contrast, the bound provided by McDiarmid's inequality is usually not sharp. We prove an error estimate for the method (Proposition 3.2); we define a codimension‐one recursive partitioning scheme and prove its convergence properties (Theorem 4.1); finally, we apply a new concentration‐of‐measure inequality to give confidence levels when empirical means are used in place of exact ones (Section 5). Copyright © 2010 John Wiley & Sons, Ltd.     

Optical,surface and magnetic properties of the Ti-doped GaN nanosheets on glass and PET substrates by thermionic vacuum arc (TVA) method

Room-temperature ferromagnetism of GaN and doped GaN materials has been reported in nanostructured form. Especially, nanoparticles show ferromagnetic properties at room temperature. In this paper, Ti-doped effects on GaN were deposited on glass and Polyethylene terephthalate (PET) substrates by thermionic vacuum arc and their room temperature magnetic properties are presented for the first time. The structure of the Ti-doped GaN was crystallized in a novel form, nano honeycomb formation. Optical and surface properties of the nano honeycombs and honeycomb nanosheets were determined. GaN and TiN phases were detected in X-ray diffraction patterns. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) device were used for imaging of the crystal structure. According to FESEM images, hexagonal crystal formations were detected for all samples. Crystal formations are very good oriented on PET substrates materials according to glass samples. The band gap value of the sample is changed by crystallization dimension. It was found that increasing crystallizations and decreasing crystal dimensions were increased the band gap of the Ti-doped GaN approximately 50?meV. Fourier transform infrared spectra and a vibrating sample magnetometer results were presented. These results confirm the Ti doped GaN honeycomb nanosheets and nano honeycombs show the room temperature ferromagnetic properties.