Withdrawal of pairs of threaded rods with small edge distances and spacings

An experimental investigation on withdrawal of pairs of screwed-in threaded rods embedded in glued-laminated timber elements is presented in this paper. Specimens with varying angles between the rod axis and the grain direction (α?=?15°, 30°, 60°, 90°) and 2 different configurations with respect to edge distances and spacings were tested. The diameter and the embedment length of the rods were 20 and 450 mm, respectively. The threaded rods were embedded in a row perpendicular to the plain of the grain. The edge distances and spacings were smaller than the minimum requirements according to Eurocode 5. The withdrawal capacity of pairs of rods was compared to the withdrawal capacity of single rods and the effective number, n _ef , was found to be in the range 1.72–1.94, despite the small edge distances and spacings. Based on the experimental results obtained, a simple approximating expression was derived for n _ef . An analytical model based on Volkersen theory with an idealized bi-linear constitutive relationship was used to estimate the withdrawal capacity and stiffness. The analytical estimations were in good agreement with the experimental results. Finally, the withdrawal stiffness was estimated by use of finite element simulations. The numerical estimations for the withdrawal stiffness were also in good agreement with the experimental results.     

A methodology for validating the renewable energy data in EU

The multidimensional character of renewable energy sources (RES) necessitates the collection of a number of related data in order to support EU policy needs. Apart from the technology and techno-physical data also socioeconomic (e.g. employment, turnover) data and R&D expenditures are of critical relevance. The monitoring of the above RES data with respect to the existing targets for RES is of significant importance. In addition to this, even though significant data gathering efforts have been implemented, a lot of fragmented data and deduced findings are currently available, which sometimes lack consistency and verification. As a result, RES data validation and completion capacity is needed in the framework of the European Union (EU) energy policy. In addition to this, agreed and validated RES data can help energy policy makers and relevant stakeholders answering to pressing energy socio-economics’ and sustainability issues. In this context, the main aim of the paper is to present a reference methodology for validating the RES Data in the EU. The development of the methodology is mainly based on the review of existing methods and ends up with recommendations for improvements in RES data aggregation and statistical interpretation, taking into consideration the related analysis of statisticians, energy technology experts and energy socio-economists.     

Arsenic Bioaccessibility in Cooked Rice as Affected by Arsenic in Cooking Water

Abstract: Rice can easily accumulate arsenic (As) into its grain and is known to be the highest As‐containing cereal. In addition, the As burden in rice may increase during its processing (such as when cooking using As‐polluted water). The health risk posed by the presence of As in cooked rice depends on its release from the matrix along the digestive system (bioaccessibility). Two types of white polished long‐grain rice, namely, nonparboiled and parboiled (total As: 202 and 190 μg As kg^?1, respectively), were cooked in excess of water with different levels of As (0, 10, 47, 222, and 450 μg As L^?1). The bioaccessibility of As from these cooked rice batches was evaluated with an in vitro dynamic digestion process. Rice cooked with water containing 0 and 10 μg As L^?1 showed lower As concentrations than the raw (uncooked) rice. However, cooking water with relatively high As content (≥47 μg As L^?1) significantly increased the As concentration in the cooked rice up to 8‐ and 9‐fold for the nonparboiled and parboiled rice, respectively. Parboiled rice, which is most widely consumed in South Asia, showed a higher percentage of As bioaccessibility (59% to 99%) than nonparboiled rice (36% to 69%) and most of the As bioaccessible in the cooked rice (80% to 99%) was released easily during the first 2 h of digestion. The estimation of the As intake through cooked rice based on the As bioaccessibility highlights that a few grams of cooked rice (less than 25 g dry weight per day) cooked with highly As contaminated water is equivalent to the amount of As from 2 L water containing the maximum permissible limit (10 μg As L^?1). Practical Application: Studies on As bioaccessibility are needed for determining human As intake from rice for use in accurate risk assessments to establish updated legislation regarding maximum level of As in food. High As bioaccessibility from parboiled rice (consumed by the majority of the people in South Asia), and the findings of high As levels in discarded rice gruel (fed to livestock), has implications for human and animal health.     

Recent progress in silicon-based solid-state solar cells

Silicon (Si)-based solar cells constitute about 90% of the photovoltaic (PV) market, and a drastic reduction in module cost and significant improvement in PV performance have been observed since its first inception in 1941. This article aims to present the comprehensive review of prominent advancements enacted in Si solar cells after the year 2000. Monocrystalline Si solar cell has been the matured technology with the record efficiency (η) of 26.6% achieved so far. As the drive to push η around 30% Schokley–Quiesser limit is foreseeable in the near future, PV community is actively striving to fabricate efficient yet cost-effective devices. Polycrystalline Si solar cells contain small-sized grains, and efforts are underway to enhance the η beyond 21.9% by controlling the recombination at grain boundaries, optimising the passivated interfaces and deposition process. Thin-film amorphous Si technology proffers low-cost fabrication process and η of 13.6% has been recorded for a multijunction solar cell. Employment of sophisticated nanowire-based light trapping schemes and dopant-free carrier-selective layers along with the development of hybrid solar cells of organic and Si materials are among the emerging research trends for Si solar cells.     

Study of performance parameter optimisation of resorption cogeneration utilising heat and mass recovery

In the present scenario, one of the global issues is energy crisis, and it is found that effective utilisation of low-grade waste heat energy as potential solution to this crisis, which could be easily used with the cogeneration plant. In this work, an attempt is made to implement a mass and heat recovery system with a basic resorption cogeneration unit. Low-grade solar energy is utilised by the expansion machine and ammonia resorption unit, and the plant produces a dual output of cooling effect and electricity. The problem of variation reaction rate is sorted out by introducing a buffer prior to the expansion machine; similarly, the deficiency of chemisorption is overcome by a pair of resorption cycles. Under various operating conditions, six resorption pairs were analysed and it was found that the SrCl₂–MnCl₂ pair to be the best pair. Exergy analyses were made using the equation solver.     

How Successful are Energy Efficiency Investments? A Comparative Analysis for Classification & Performance Prediction

Computational Economics - Increasing the financial institutions’ deployment of capital in energy efficiency investments remains still a challenge. The present article is intended to...     

Effect of Copper and Zirconium Addition on Properties of Fe-Co-Si-B-Nb Bulk Metallic Glasses

In this research work, iron-based bulk metallic glasses (BMGs) have been fabricated, characterized and compared with Fe-Si alloy. BMG alloys of composition ((Fe_0.6Co_0.4)_0.75B_0.20Si_0.05)₉₆Nb₄) were synthesized by suction casting technique using chilled copper die. Effect of copper and zirconium addition on magnetic, mechanical, thermal and electrochemical behavior of ((Fe_0.6Co_0.4)_0.75B_0.20Si_0.05)₉₆Nb₄ BMGs was investigated. Furthermore, effect of annealing on nano-crystallization and subsequently on magnetic and mechanical behavior was also analyzed. Amorphousness of structure was evidenced by XRD analysis and microscopic visualization, whereas nano-crystallization behavior was identified by peak broadening of XRD patterns. Magnetic properties, measured by vibrating sample magnetometer, were found to be improved for as-cast BMG alloys by copper addition and further enhanced by nano-crystallization after annealing. Mechanical properties were observed to be increased by zirconium addition while slightly declined by copper addition. Potentiodynamic polarization analysis manifested the positive role of zirconium in enhancing corrosion resistance of BMGs in acidic, basic and brine mediums. Moreover, mechanical properties and corrosion analysis results affirmed the superiority of BMG alloys over Fe-Si alloy.     

Preliminary study on the fabrication of aluminium foam through pressure assisted sintering dissolution process

This paper discusses the improvement made by pressure assisted sintering dissolution process (PASDP) as opposed to the solid-state sintering dissolution process (SSSDP) which was used in producing a much improved open celled aluminium foam. The improvements leads to an aluminium foam possessing a high dense of cell wall which is attainable in a much shorter time and possesses superior mechanical properties. By varying the local sodium chloride (NaCl) volume fractions in the sodium chloride/aluminium (NaCl/Al) compact, it is possible to fabricate aluminium foam with different relative densities. When subjected to monotonic compression mode, the fabricated aluminium foam exhibits typical stress–strain behaviour of metallic foam. The principles of Taguchi's Design of Experiments were employed to optimize processing factors for the fabrication of aluminium foam. Results were analysed based on Taguchi's signal to noise ratio (S/N) and analysis of variance (ANOVA) techniques in order to obtain the optimum combination of process parameter settings. Results indicate that the most notable factor influencing the fabrication of Al foam was the compaction at elevated temperature, followed by temperature, time and the process heating rate. The optimum processing parameters for the PASDP process were then predicted based on these results.     

Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera

Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional "straight-cut" (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors.     

Generation of soliton and bound soliton pulses in mode-locked erbium-doped fiber laser using graphene film as saturable absorber

We report an observation of soliton and bound-state soliton in passive mode-locked fibre laser employing graphene film as a passive saturable absorber (SA). The SA was fabricated from the graphene flakes, which were obtained from electrochemical exfoliation process. The graphene flakes was mixed with polyethylene oxide solution to form a polymer composite, which was then dried at room temperature to produce a film. The film was then integrated in a laser cavity by attaching it to the end of a fibre ferrule with the aid of index matching gel. The fibre laser generated soliton pulses with a 20.7 MHz repetition rate, 0.88 ps pulse width, 0.0158 mW average output power, 0.175 pJ pulse energy and 18.72 W peak power at the wavelength of 1564 nm. A bound soliton with pulse duration of ~1.04 ps was also obtained at the pump power of 110.85 mW by carefully adjusting the polarization of the oscillating laser. The formation of bound soliton is due to the direct pulse to pulse interaction. The results show that the proposed graphene-based SA offers a simple and cost efficient approach of generating soliton and bound soliton in mode-locked EDFL set-up.