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A general numerical method for finding the steady state solution of a cyclic system is presented. The method determines the initial values by enforcing the conditions of periodicity. In this way the initial value is found by integrating through only one cycle, often resulting in a considerable saving of computing effort. The method is applicable to any linear discrete set of difference equations with periodic parameters and forcing functions. The application of the method to a single pole representation of heat flow in buildings is demonstrated.

The design of optimum pipe and duct networks with available procedures is difficult, if not impossible. A more efficient procedure that will automatically produce the optimum design is required. Such a procedure is presented in this article. The design is formulated as a constrained nonlinear optimization problem. This problem is solved using a unique numerical optimization algorithm. The solution entails the calculation of the cross sectional dimensions of the ducts and pipes so that the life cycle cost of the network is minimized. The topology equations are derived using graph theory thereby allowing complex networks with loops to be designed numerically. A duct network consisting of a fan and 35 duct sections is designed according to certain specifications. Using the proposed procedure optimum designs were obtained within seconds on a 33 MHz 486 micro‐computer. The procedure was further applied to the optimization of a coal pipeline. It is shown that the optimized solution will cost 14% ($8 million) less than the previous design with conventional design techniques.

The cross‐correlation flow measurement technique, applied for measuring the coolant flow rate in a nuclear reactor, was calibrated with the use of numerical simulations of turbulent flow. The three‐dimensional domain was collapsed into two dimensions. With a two‐dimensional calculation of steady‐state flow with transient thermal characteristics the response of thermocouples to a temperature variation was calculated. By cross‐correlating the calculated thermocouple responses, the link between total flow rate and measured transit times was made. The reliability of the calibration was estimated at ±4.6%. In addition, a measured velocity profile effect was successfully predicted.

Far infrared radiation (FIR) has been shown to have physiological effects when used as a treatment modality for certain medical conditions. Athletic apparel are currently commercially available that are constructed with fabrics that purportedly emit FIR. If apparel with this technology are capable of inducing positive physiological effects, then there may be important implications when worn by an athlete during exercise. The purpose of this study is to examine whether FIR apparel has an effect on oxygen consumption during exercise at submaximal intensities. Twelve male cyclists have completed submaximal incremental cycling tests. Each subject is tested on 4 separate days, twice while wearing a full body Control garment, and twice while wearing a similar garment made out of FIR fabric. Throughout each cycling test, the volume of oxygen uptake is monitored by using a breathing mask and metabolic analysis cart. At lower cycling intensities, the subjects consume statistically significantly less oxygen when wearing the FIR apparel compared to the Control garment, despite performing the same amount of mechanical work. Additional research is required to determine the implication of this effect for a training or competing athlete; however, the results indicate that this apparel technology does elicit a physiological effect.

The purpose of this study is to investigate the utility of carbon black containing coating formulations that are conventionally used for pigment printing of textiles in fabricating electrically heated fabrics.

Specifically, electrical and thermal characterisation of the coating system was carried out to establish the feasibility of the system for use in the manufacturing of flexible heating elements on textile substrates. The coating formulations were applied via a simple padding technique followed by stitching the electrodes using a conductive yarn.

The heating elements of different sizes thus produced showed Ohmic behaviour as a resistor and attained a targeted temperature difference of up to 40°C within the applied voltage range. A prototype heater was also produced, and thermography results showed uniform heating and cooling of the heater that was incorporated into a jacket.

The proposed method is envisaged to be very practical for the realisation of completely textile-based heating elements of different shapes and sizes. Furthermore, the proposed manufacturing method can be used to convert conventional ready-made articles of clothing into heated textiles for various applications.

This study aims to test the effects of Celliant armbands on grip strength in subjects with chronic wrist and elbow pain. Celliant® is a functional textile fabric containing minerals that emit infrared radiation (IR) in response to body heat. IR-emitting fabrics have biological effects including the reduction of pain and inflammation and the stimulation of muscle function.

A randomized placebo-controlled trial recruited 80 subjects (40 per group) with a six-month history of chronic wrist or elbow pain (carpal tunnel syndrome, epicondylitis or arthritis) to wear an armband (real Celliant or placebo fabric) on the affected wrist or elbow for two weeks. Grip strength was measured by a dynamometer before and after the two-week study.

For the placebo group, the mean grip strength increased from 47.95 ± 25.14 (baseline) to 51.69 ± 27.35 (final), whereas for the Celliant group, it increased from 46.3 ± 22.02 to 54.1 ± 25.97. The mean per cent increase over the two weeks was +7.8% for placebo and +16.8% for Celliant (p = 0.0372). No adverse effects was observed.

Limitations include the wide variation in grip strength in the participants at baseline measurement, which meant that only the percentage increase between baseline and final measurements showed a significant difference. Moreover, no subjective measurements of pain or objective neurophysiology testes was done.

Celliant armbands are easy to wear and have not been shown to produce any adverse effects. Therefore, there appears to be no barrier to prevent widespread uptake.

IR-emitting textiles have been studied for their beneficial effects, both in patients diagnosed with various disorders and also in healthy volunteers for health and wellness purposes. Although there are many types of textile technology that might be used to produce IR-emitting fabrics, including coating of the fabric with a printed layer of ceramic material, incorporating discs of mineral into the garment, the authors feel that incorporating ceramic particles into the polymer fibers from which the fabric is woven is likely to be the most efficient way of achieving the goal.

Celliant armbands appear to be effective in painful upper limb inflammatory disorders, and further studies are warranted. The mechanism of action is not completely understood, but the hypothesis that the emitted IR radiation is absorbed by nanostructured intracellular water provides some theoretical justification.

The application of far-infrared energy to skin is expected to lead to vasodilatation of the skin surface, consequently warming the skin, and promoting sleep induction. The purpose of this paper was to test whether bedsheets impregnated with bioceramic far-infrared technology would improve the perception of sleep in a sample of healthy adults.

Twenty-nine adults consented to participate, randomizing 17 to the far-infrared bedsheets and 12 to the control bedsheets. Two of the control participants dropped out prior to randomization and prior to completing any assessments and therefore are excluded from the analyses. After baseline assessment, participants slept on their randomly assigned sheets for five weeks, followed by a one week “wash out”. Insomnia symptoms were assessed with the Insomnia Severity Index, depression symptoms with the Patient Health Questionnaire, “vigor” and “fatigue” with the Profile of Mood States, and napping behavior with daily sleep diaries.

During the period of randomization, the participants on the far-infrared sheets reported fewer insomnia symptoms and less napping. This advantage was lost during the wash out period.

Far-infrared technology produces benefits on reported sleep in healthy normal adults.