Lattice thermal conductivity of disordered NiPd and NiPt alloys

Numerical calculations of lattice thermal conductivity are reported for the binary alloys NiPd and NiPt. The present work is a continuation of an earlier paper by us [PRB, 72, 214207 (2005)]which had developed a theoretical framework for the calculation of configuration-averaged lattice thermal conductivity and thermal diffusivity in disordered alloys. The formulation was based on the augmented space theorem combined with a scattering diagram technique. In this paper we shall show dependence of the lattice thermal conductivity on a series of variables like phonon frequency, temperature and alloy composition. The temperature dependence of $\kappa(T)$ and its realtion to the measured thermal conductivity is discussed. The concentration dependence of $\kappa$ appears to justify the notion of a minimum thermal conductivity as discussed by Kittel, Slack and others. We also study the frequency and composition dependence of the thermal diffusivity averaged over modes. A numerical estimate of this quantity gives an idea about the location of mobility edge and the fraction of states in the frequency spectrum which is delocalized.Comment: 23 pages, 18 figure

Bioenergy production and nutrients removal by green microalgae with cultivation from agro-wastewater palm oil mill effluent (POME) - A review

Environmental pollution specifically wastewater is gaining attention both in the developed and developing countries. Malaysia is considered as one of the major palm oil producers in the world. Therefore, it is important to develop an environmental friendly and economic method to treat palm oil mill effluent (POME). The wastewater can serve as an economical nutrient source or substrate that can support the cultivation of microalgae. This can be a great nutrient for algal cultivation at the same time as remediating effluent and generating biomass. Nowadays, many microalgae species are being investigated to determine their potential and effectiveness for phytoremediation application, especially high growth rate. However, using synthetic media for growing microalgae in a mass scale is costly. It is acknowledged that POME (as nutrients enriched media) assisted enhanced microalgae growth under certain condition can considerably reduce the presence of organic and inorganic compounds. In this review, the potential of wide range of the predominant microalgae species with main focus on green microalgae (high removal efficiency): Chlamydomonas sp and Chlorella sp were investigated. Moreover, we discussed about the history, methods and future prospects in nutrients removal by green microalgae comprehensively. This review discusses several potential strategies for tackling the environmental issue generated by agro-waste water POME with enhancement of biomass productivity which can be used as an alternative for energy production

Crystal structure of 1-butyl-2,3-di-methylimidazolium dicarba-7,8-nido-undecaborate

AL thanks Professor Maitland Jones for the generous donation of the starting orthocarborane stock and Dr John Holbrey for the supply of imidazolium halide reagents. The research support by ACS PRF and Cottrell College awards (44692.01-GB and CC6755) is gratefully acknowledged.Peer reviewedPublisher PD

Note: Non-invasive optical method for rapid determination of alignment degree of oriented nanofibrous layers

This paper presents a rapid non-destructive method that provides information on the anisotropic internal structure of nanofibrous layers. A laser beam of a wavelength of 632.8 nm is directed at and passes through a nanofibrous layer prepared by electrostatic spinning. Information about the structural arrangement of nanofibers in the layer is directly visible in the form of a diffraction image formed on a projection screen or obtained from measured intensities of the laser beam passing through the sample which are determined by the dependency of the angle of the main direction of polarization of the laser beam on the axis of alignment of nanofibers in the sample. Both optical methods were verified on Polyvinyl alcohol (PVA) nanofibrous layers (fiber diameter of 470 nm) with random, single-axis aligned and crossed structures. The obtained results match the results of commonly used methods which apply the analysis of electron microscope images. The presented simple method not only allows samples to be analysed much more rapidly and without damaging them but it also makes possible the analysis of much larger areas, up to several square millimetres, at the same time

A review on the economic feasibility of composting for organic waste management in Asian countries

The rising rate of population growth and industrial development mainly in urban areas have led to significant increase in municipal solid waste (MSW) production. It has been a challenge to materialise a sustainable solid waste management notably in many developing countries. Organic portion represents a significant component in the municipal solid waste across countries with different level of income, ranging from about 25 to 70 %. Composting can be a viable option to manage waste sustainably by transforming waste into value-added fertiliser. Large-scale operation of composting is confronted with concern over feasible economic performance, which varied following different mode of operation. This study aims to review the economic feasibility (EF) on two different composting systems, which are the in-vessel and windrow system, implemented in several developed and developing countries. The review considered the cost factors for both composting systems, including the capital cost and operating cost. The return on investment (ROI) is estimated for both composting systems based on the potential cost benefits from the compost sale and the saving of waste tipping fee. This review provides a better insight into the desirability and applicability of both composting systems as an alternative to the landfilling practice. It is expected that the review of the various composting system could be very useful for improving the sustainable composting technology in the developing countries

Cost optimisation of a flexible heat exchanger network with fluctuation probability using break-even analysis

Heat exchanger network (HEN) which is designed to achieve the maximum energy recovery (MER) involves the integration and interactions of multiple process streams. Small disturbances on one stream can affect other connecting streams. In order to manage these disturbances, the process to process and utility heat exchangers with bypass streams installation are typically overdesigned. However, overdesign also means higher capital investment. This study presents the cost optimisation of flexible MER HEN design which considers the fluctuation probability using break-even analysis. Data were extracted for the Pinch study and assessment for flexibility and MER was performed. The MER heat exchanger maximum size (MER-HEM) is able to handle the most critical supply temperature fluctuations while minimising the utility consumption. The overdesign factor can affect the total annualised cost at a certain probability of fluctuation occurrence. Thus, the break-even analysis of the MER-HEM is performed to determine the probability that resulted in high savings of total annualised cost. Two Scenarios (A and B) with different fluctuation probabilities were used to demonstrate the methodology. Application of the proposed methodology on an Illustrative Case Study shows that, for the fluctuation at hot stream H1, the MER-HEM gives the optimum annualised total cost for Scenario A with additional savings of 10 %. For Scenario B, the MER heat exchanger original size (MER-HEO) is the optimum, giving an additional savings of 4 %. For cold stream C1, the MER-HEO is the optimum for Scenario A, giving an extra savings of 4 % whereas the MER-HEM is the optimum for Scenario B, yielding an extra savings of 9 %

Nutrient in leachate of biowaste compost and its availability for plants

Compost leachate (CL) is a liquid by-product of compost that contains carbon, nitrogen, phosphorus, potassium and trace elements. It can partially replace the commercial liquid fertilisers to promote plant growth. However, CL may contain heavy metals, phytotoxic substances such as ammonia, organic compounds of low molecular weight, high level of salt and oils. Treatment of leachate is required to avoid the damage on the plant. This paper aims to review the nutrient and physical characteristics of the CL from three types of bio-wastes, i.e. municipal solid waste, animal waste and green waste. The effects of plants treated with CL in terms of rate and nutrient absorption were discussed. The nutrient and physical composition of the leachate is highly variable due to the diversity of the sources and age of the leachate. Compost leachate from municipal solid waste contains the highest chemical oxygen demand (COD) (15,188 – 105,300 mg/L) followed by those from animal waste (6,542 – 100,000 mg/L) and green waste (804 – 1,152 mg/L). The difference in COD is due to the difference in organic carbon content in the biowaste. Other physical parameters, such as electrical conductivity and pH, are correlated with the organic carbon content. For nutrient composition, municipal solid waste leachate contains the highest nitrogen content (630 – 2,438 mg/L), green waste has the highest potassium content (500 – 1,000 mg/L), while animal waste has the highest phosphate content (170 – 500 mg/L). The nutrient contents of CL derived from different biowaste reviewed in this study serves as a guideline for users to estimate the dilution rate and further nutrient formulation required for the application of CL on plants

On the continuing relevance of Mandelbrot’s non-ergodic fractional renewal models of 1963 to 1967

The problem of “1∕ƒ” noise has been with us for about a century. Because it is so often framed in Fourier spectral language, the most famous solutions have tended to be the stationary long range dependent (LRD) models such as Mandelbrot’s fractional Gaussian noise. In view of the increasing importance to physics of non-ergodic fractional renewal models, and their links to the CTRW, I present preliminary results of my research into the history of Mandelbrot’s very little known work in that area from 1963 to 1967. I speculate about how the lack of awareness of this work in the physics and statistics communities may have affected the development of complexity science, and I discuss the differences between the Hurst effect, “1∕ƒ” noise and LRD, concepts which are often treated as equivalent

Trends of European research and development in district heating technologies

There is a considerable diversity of district heating (DH) technologies, components and interaction in EU countries. The trends and developments of DH are investigated in this paper. Research of four areas related to DH systems and their interaction with: fossil fuels, renewable energy (RE) sources, energy efficiency of the systems and the impact on the environment and the human health are described in the following content. The key conclusion obtained from this review is that the DH development requires more flexible energy systems with building automations, more significant contribution of RE sources, more dynamic prosumers׳ participation, and integration with mix fuel energy systems, as part of smart energy sustainable systems in smart cities. These are the main issues that Europe has to address in order to establish sustainable DH systems across its countries.This research was conducted in collaboration between Wrocław University of Technology (Poland) and Brunel University London (UK). The support for the Polish team was by the Ministry of Science and HigherEducationunderGrantno.50532

Scale issues in soil moisture modelling: problems and prospects

Soil moisture storage is an important component of the hydrological cycle and plays a key role in land-surface-atmosphere interaction. The soil-moisture storage equation in this study considers precipitation as an input and soil moisture as a residual term for runoff and evapotranspiration. A number of models have been developed to estimate soil moisture storage and the components of the soil-moisture storage equation. A detailed discussion of the impli cation of the scale of application of these models reports that it is not possible to extrapolate processes and their estimates from the small to the large scale. It is also noted that physically based models for small-scale applications are sufficiently detailed to reproduce land-surface- atmosphere interactions. On the other hand, models for large-scale applications oversimplify the processes. Recently developed physically based models for large-scale applications can only be applied to limited uses because of data restrictions and the problems associated with land surface characterization. It is reported that remote sensing can play an important role in over coming the problems related to the unavailability of data and the land surface characterization of large-scale applications of these physically based models when estimating soil moisture storage.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline