An investigation of the use of heat pipes for machine tool spindle bearing cooling

The results of an experimental investigation into the practicality of using a heat pipe installed in the spindle of a milling machine to remove the heat produced in the spindle bearings which is capable of causing thermal distortion and cutting error are presented in the paper. Measurements of the variation of bearing temperature with time are reported at four different spindle speeds when there was no heat pipe installed, when the heat pipe was cooled by air and when the heat pipe was cooled by an ice/water mixture. Analysis of the results by a simple heat transfer model indicates that the particular heat pipe used was capable of removing up to 160 W with a corresponding 50% reduction in the rise of the bearing temperature above the temperature of the surrounding air at steady operating conditions.     

Binary polymer blend of ArPTU/PI with advanced comprehensive dielectric properties and ultra-high thermally stability

Flexible high-temperature polymeric dielectrics with advanced dielectric properties are urgently demanded in various applications. In this work, series of polymer blend films were prepared from aromatic polythiourea (ArPTU) and polyimide (PI). The experimental results revealed that the blend films were properly engineered to achieve higher breakdown strength, greater dielectric constant, and larger energy density than pure PI film. For instance, the optimum property was obtained from the blend film with 10 wt% ArPTU, exhibiting prominent dielectric properties (K = 4.52, E_b = 443 MV/m), enhanced energy density (4.00 J/cm³) as well as excellent heat resistance (T_g = 419°C). In addition, stable dielectric properties at broad temperature range from −50 to 250°C were also acquired. It is deduced that the good compatibility from ArPTU and PI with similar polarity are responsible for the improved properties. The superior comprehensive properties which combine the advantages of ArPTU and PI suggest the potential applications of ArPTU/PI blend film in high-temperature dielectric areas.     

Recent Advances in Rolling 2D TMDs Nanosheets into 1D TMDs Nanotubes/Nanoscrolls

Transition metal dichalcogenides (TMDs) van der Waals (vdW) 1D heterostructures are recently synthesized from 2D nanosheets, which open up new opportunities for potential applications in electronic and optoelectronic devices. The most recent and promising strategies in regards to forming 1D TMDs nanotubes (NTs) or nanoscrolls (NSs) in this review article as well as their heterostructures that are produced from 2D TMDs are summarized. In order to improve the functionality of ultrathin 1D TMDs that are coaxially combined with boron nitride nanotubes and single-walled carbon nanotubes. 1D heterostructured devices perform better than 2D TMD nanosheets when the two devices are compared. The photovoltaic effect in WS₂ or MoS₂ NTs without a junction may exceed the Shockley–Queisser limit for the above-band-gap photovoltage generation. Photoelectrochemical hydrogen evolution is accelerated when monolayer WS₂ or MoS₂ NSs are incorporated into a heterojunction. In addition, the photovoltaic performance of the WSe₂/MoS₂ NSs junction is superior to that of the performance of MoS₂ NSs. The summary of the current research about 1D TMDs can be used in a variety of ways, which assists in the development of new types of nanoscale optoelectronic devices. Finally, it also summarizes the current challenges and prospects.     

Designing Visceral,Behavioural and Reflective Products

Designers and manufacturers often see consumption as the primary objective of a product–with implications such as discarded products,obsolete wastes,and ecological degradation.The paper aims to find the answer to the question,how emotional design can adapt the discarded and undesirable products into something valuable in a long term?This paper presents a framework combining Chapman’s theory and Norman’s theory on three levels of emotional design to highlight what long lasting connection with products entails.A design approach is presented combing the Wabi Sabi philosophy that promotes the celebration of decay and damage.This is used as one of the design principles for the experiments conducted on discarded products.Through constant user interaction before,during and after the experiments the evaluation of design as an agent of transformation is done.The user conducted the evaluation based on the Kansei elements of looks,sound,smell,and feel of the product.The experiments confirmed that a long-term value is only achieved through redesigning and reconstructing the perception of people towards products on a reflective level,rather than the visceral and behavioural elements of the product.The research found attachment to the visceral and behavioural elements of a product instead of an emotional one was causing users to discard products faster than required.The research indicated that many people,including designers and manufacturers,are unconsciously focusing on usability(behavioural level)and physical look(visceral level)of a product that are easily replaced,than on a meaningful way (reflective level)to create and maintain long-lasting emotions.The research concluded with a proposition towards digitization of products which could perhaps be an all round solution to make products more appropriate to human emotions.Digitization could give products the ability to capture,store and then communicate the stories,journey and memories back,in order to empower people to understand the value of longer-term use of products.     

Application of transmission FT-IR spectroscopy for the trans fat determination in the industrially processed edible oils

The amount of trans fatty acids (TFA) in fourteen industrially hydrogenated and deodorized oils was determined. To achieve better sensitivity 200 μm KCl cell was used in transmission Fourier transform infrared (FT-IR) spectroscopy. The results of transmission FT-IR spectroscopy were evaluated by gas chromatography (GC) with flame ionization detector (FID), and found to be comparable. All analyzed cooking oil samples had a lower trans content of 0.4–1.8%. Trans fatty acid contents of partially hydrogenated oil samples were relatively higher as comparable to those of the cooking oils. Among the samples examined, the highest level was found to be at 26.5% and 25.7% by the GC–FID and FT-IR spectroscopy, respectively. Due to harmful effects, high amounts of trans fatty acids in partially hydrogenated oils is an alarming issue for the consumer’s health and quality control authorities.     

A new analytical/iterative approach to statistical delay characterization of cmos digital combinational circuits

This paper is believed to be one of the first attempts to statistically characterize signal delays of basic CMOS digital building blocks. Analytic expressions in terms of the transistor geometries and technological process variations are provided for fast delay computations, to be used for manufacturing yield optimization, delay variability reduction and general VLSI circuit design for quality. the proposed approach is novel in several ways: (1) It is a combination of an accurate, semi-empirical MOS transistor model with the use of an efficient interpolation technique to link the non-physical model parameters to the ‘designable’ and ‘noise’ factors. (2) It uses several newly developed analytical delay formulae where possible and simple iterative solutions where direct analytical solutions do not exist. (3) the resulting hybrid analytical/iterative models are tuned, if necessary, to enhance the overall statistical accuracy. (4) Local delays are combined together for the analysis of complex combinational VLSI circuits. (5) C-code is generated for specific delay paths to further increase efficiency (improvement in analysis times by two to four orders of magnitude with respect to SPICE, with about 5%-10% accuracy). Examples of statistical delay characterization are used to illustrate the high accuracy of the proposed approach in modelling the influence of the ‘noise’ parameters on circuit delay relative to direct SPICE-based Monte Carlo analysis. the important impact of the proposed approach is that statistical evaluation and optimization of delays in much larger VLSI circuits will become possible.     

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.     

Project Oriented Problem Based Learning: A Wireless Sensor Network Perspective

Every nation rely on latest engineering technologies to foster in today’s technological era. Wireless Sensor Networks (WSNs) is one of the latest emerging technologies being the center of interest of today’s researchers. All the researchers work hard to produce quick deliverables through Research and Development (RandD) and by applying different learning pedagogues. Currently, the learning pedagogues in Engineering RandD are Project Based Learning and Problem Based Learning (PBL). Based on these pedagogues, this paper propose and implements a hybrid pedagogy called Project Oriented PBL (PO-PBL) which is time effective and result oriented learning pedagogy. It has resulted in providing impetus to RandD in WSNs. Further the proposed pedagogy is divided into two paradigms namely PO-PBL Macro Model and PO-PBL Micro Model. We observed that PO-PBL Macro Model results in optimal number of deliverables in time restricted manner over large scale. Moreover, we have also implemented PO-PBL Micro Model, compared it with PO-PBL Macro Model and propose PO-PBL Micro Model as basis for designing self-learning algorithm for WSNs devices.     

Visual control of step length during overground locomotion: Task-specific modulation of the locomotor synergy.

This study evaluated the dynamics of gait adaptations during overground locomotion. Step length of 20 Ss increased or decreased (by 50% or 30%) on visual cues given at several different times (3 or 2) in the step cycle while walking or running, respectively. Ground reaction forces and temporal data were analyzed for each of the 10 trials per condition. Results showed that both vertical and horizontal impulses are modulated. The cuing time affected the way Ss altered step length. For example, during late cuing Ss made changes during free flight phase. Both magnitude and duration of force were altered suggesting modulation of a higher order parameter, the impulse. Success rate was lower for later cuing times. It was also lower for shorter step length than longer one. This suggests that balance requirements constrain the adaptations that can be made. The study implies far greater on-line peripheral control of locomotion than suggested by a dominant central pattern generator control theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)