Structure–Transport Correlation Reveals Anisotropic Charge Transport in Coupled PbS Nanocrystal Superlattices

The assembly of colloidal semiconductive nanocrystals into highly ordered superlattices predicts novel structure-related properties by design. However, those structure–property relationships, such as charge transport depending on the structure or even directions of the superlattice, have remained unrevealed so far. Here, electric transport measurements and X-ray nanodiffraction are performed on self-assembled lead sulfide nanocrystal superlattices to investigate direction-dependent charge carrier transport in microscopic domains of these materials. By angular X-ray cross-correlation analysis, the structure and orientation of individual superlattices is determined, which are directly correlated with the electronic properties of the same microdomains. By that, strong evidence for the effect of superlattice crystallinity on the electric conductivity is found. Further, anisotropic charge transport in highly ordered monocrystalline domains is revealed, which is attributed to the dominant effect of shortest interparticle distance. This implies that transport anisotropy should be a general feature of weakly coupled nanocrystal superlattices.     

Practical support for evaluating efficiency factors of a space heating system in cold climates

Plenty of technical norms, included in the EPBD umbrella, assesses the performance of buildings or its sub-systems in terms of efficiency. In particular, EN 15316 and its sub-sections determine the efficiency factors of a space heating system. This paper focuses on the estimation of efficiency factors for hydronic panel radiators. The assessment of efficiency factors occurs by evaluating the amount of heat emitted from the heat emitter and the thermal losses towards building envelope. A factor that influences the heat emitted is the location of radiator connection pipes. Connection pipes can be located on opposite side or at the same side of the radiator. To better estimate the heat emitted from the radiator with different location of connection pipes, a transient model with multiple storage elements is implemented in a commercial building simulation software and validated versus available experimental measurements. Sensitivity analysis encompasses the variations of heat losses due to the building location in different climates, the changing of the active thermal mass and the type of radiator local control. The final outcome of this paper is a practical support where designers and researchers can easily assess the efficiency factors for space heating system equipped with hydronic panel radiators of buildings located in Sweden. As main results, (i) the efficiency factor for control is higher in Northern climates (Luleå) than in Southern climates (Gothenburg), (ii) heavy-weight active thermal masses allow higher efficiency factors than light active thermal masses, and (iii) connection pipes located on the same side of the hydronic panel radiator enable higher efficiency factors than pipes located on opposite side.     

Characteristics and Functionality Enhancement by Glycosylation of Bitter Melon (Momordica charantia) Seed Protein

Seeds of ripe bitter melon (Momordica charantia) contain approximately 30% protein. However, this protein, which is less functional than soy protein, may have desirable functionalities as a food ingredient after modification. Bitter melon seed protein isolate (BMSPI) was prepared under optimal extraction conditions (defatted meal to 1.3 M NaCl was 1:10 w/v; pH 9.0) and its functional properties were investigated before and after modification by glycosylation. Glycosylation was conducted at varying relative humidities (50%/65%/80%) and temperatures (40 °C/50 °C/60 °C) using a response surface central composite design. Degree of glycosylation (DG) ranged from 39.3 to 52.5%, 61.7 to 70.9%, and 81.2 to 94.8% at 40 °C, 50 °C, and 60 °C, respectively (P values < 0.0001). Denaturation temperatures of all DGs ranged from 111.6 °C to 114.6 °C, while unmodified/native BMSPI had a value of 113.2 °C. Surface hydrophobicity decreased to approximately 60% when the DG was maximal (94.8%). Solubility decreased almost 90% when the DG was maximal in comparison to the native BMSPI (62.0%). Emulsifying activity increased from 0.35 to 0.80 when the DGs were ≥80%, while emulsion stability increased from 63 to 72 min when the DGs were greater than 70%. A similar trend was observed with foaming capacity and foaming stability of the glycosylated proteins. This glycosylated BMSPI with improved emulsifying and foaming properties could be used as an ingredient in food products where such properties are required.     

An alternative solution of the water shortage problem in Libya

In Libya there is a growing awareness of increasing demand for fresh water while fossil groundwater supply is limited. This situation of water supply has become more problematic with rapidly increasing population and low rainfall. Hence soon after the discovery of fresh groundwater in the deserts of southern Libya, the local authority has made huge efforts to address its water deficit problems, mainly through the implementation of “The Great Manmade River Project” to sustain its economy. Especially the agriculture sector exceeds its traditional supplies. The Libyan authority began to design and install the hydraulic infrastructure needed to withdraw and transport this fossil water to various demand sites along its Mediterranean coast where most of the population lives and where the water is used. There is an over-exploitation of fossil groundwater resources to meet the irrigation demands as a result of adapting a self-sufficing policy in food. Rapid development of agricultural activity, expansion of irrigated areas and over irrigation practices will lead to more depletion of water resources since most of the country's groundwater resources are non-renewable. The supply-driven approach for water management has demonstrated its inability to deliver a substantial degree of water sustainability on the national Libyan level. Despite the strenuous efforts made by the country, it still faces serious water deficits due to continuously increasing water demands beyond the limits of its available water resources. As pressure on water converges on the country's fossil water resources, an immediate reconsideration of agricultural water extractions is needed and appropriate actions have to be implemented in response to its huge consumption. This policy aims at rescuing the present water situation and at avoiding serious environmental and economical crises. Reorganisation of the water consumption pattern, to maintain the country's standard of living and to ensure the economical security for the future generation is drastically needed. This paper considers the country's water management that requires water policy reforms, with emphasis on supply and demand management measures and improvement of the legal and institutional provisions. This could be achieved by reviewing agricultural water policies in order to minimise some local deficits in water resources and to avoid water quality deterioration in the coastal areas. Developing additional non-conventional sources of water supply needs to be considered. This should be supported by creating authorised water institutions lead by a high-professional staff and enabling them in making the appropriate legislation and decisive measurements to allocate water among consumptive sectors as well as to ensure the protection of the environment.     

Multi-channel Detector Module for Multi-energy Gamma Ray Computed Tomography

Journal of Signal Processing Systems - In this paper an enhanced signal processing electronics for an existing multi-channel detector module for gamma ray computed tomography is presented. The...     

Robustness and static-positional accuracy of the SteamVR 1.0 virtual reality tracking system

Virtual Reality - The use of low-cost immersive virtual reality systems is rapidly expanding. Several studies started to analyse the accuracy of virtual reality tracking systems, but they did not...     

Electrochemical coupling reactions of benzyl halides on a powder cathode and cavity cell

Benzyl halides adsorbed on a cathode made of pure or silver-doped graphite powder were reduced in an undivided cell using an aqueous electrolyte and an inert anode, in the absence or presence of benzaldehyde. The product ratio is influenced by the applied potential, the leaving halide group and presence/absence of silver electrocatalyst. The highest yield of bibenzyl was obtained from the electrolysis of benzyl bromide on silver-doped graphite at a constant potential equal to −1.0 V vs Ag/AgCl (sat. KCl). Benzyl chloride is less prone to dimerization, but undergoes efficient carbonyl addition to benzaldehyde, especially in the presence of silver. The results can be interpreted as a competition of radical and anionic processes.