Solar thermal drying of canarium indicum nuts

Many situations exist in rural areas of developing countries where the help of simple technology can make substantial positive impacts on living conditions, finance, and in this case; sustainability. In the Melanesia region, there are numerous areas identified as needing improvement, including indigenous food preservation which will be addressed with a proposed solar thermal solution utilizing locally available materials as much as possible for low cost local construction. The current knowledge of the drying requirements for the product chosen in this study is quite limited. However, it is believed that solar thermal drying might be feasible for the remote sunny regions as in Melanesia. This paper describes the processes involved in determining the drying parameters of the Canarium indicum nut, and the proposed solar dryer designs that have been considered for the particular environmental conditions and product specifications. Through the selection process, a mixed mode, low-tunnel solar dryer was chosen as the best match to satisfy the different parameters.<br /

Temperature dependence of the radiative recombination coefficient of intrinsic crystalline silicon

The radiative recombination coefficient B(T) of intrinsic crystalline silicon is determined as a function of temperature over the temperature range 77–300 K. We observe that B(T) decreases as a function of temperature and we compare our results to previously published contradictory data from the literature. The radiative recombination coefficient is calculated from the absorption coefficient for band-to-band transitions, which we determine at different temperatures from photoluminescencespectra measured on planar high resistivity float zone silicon wafers. Photoluminescencespectra could be detected over a large range of more than five orders of magnitude, which allowed us to determine extremely low values of the absorption coefficient in the spectral range where absorption processes are accompanied by the simultaneous absorption of up to four phonons.The Centre of Excellence for Advanced Silicon Photovoltaics and Photonics is supported under the Australian Research Council’s Centres of Excellence Scheme. One author (T.T.) would like to thank the Alexander von Humboldt foundation for a Feodor Lynen-Scholarship while another (M.A.G.) acknowledges the award of an Australian Government Federation Fellowship

Spectroscopic study of the Br−+CH3I→I−+CH3Br SN2 Reaction

Mass spectrometry and anion photoelectron spectroscopy have been used to study the gas-phase SN2 reaction involving Br- and CH3I. The anion photoelectron spectra associated with the reaction intermediates of this SN2 reaction are presented. High-level CCSD(T) calculations have been utilised to investigate the reaction intermediates that may form as a result of the SN2 reaction along various different reaction pathways, including back-side attack and front-side attack. In addition, simulated vertical detachment energies of each reaction intermediate have been calculated to rationalise the photoelectron spectra

Hydrogen bonding versus halogen bonding: Spectroscopic investigation of gas-phase complexes involving bromide and chloromethanes

Hydrogen bonding and halogen bonding are important non-covalent interactions that are known to occur in large molecular systems, such as in proteins and crystal structures. Although these interactions are important on a large scale, studying hydrogen and halogen bonding in small, gas-phase chemical species allows for the binding strengths to be determined and compared at a fundamental level. In this study, anion photoelectron spectra are presented for the gas-phase complexes involving bromide and the four chloromethanes, CH3Cl, CH2Cl2, CHCl3, and CCl4. The stabilisation energy and electron binding energy associated with each complex are determined experimentally, and the spectra are rationalised by high-level CCSD(T) calculations to determine the non-covalent interactions binding the complexes. These calculations involve nucleophilic bromide and electrophilic bromine interactions with chloromethanes, where the binding motifs, dissociation energies and vertical detachment energies are compared in terms of hydrogen bonding and halogen bonding

Closing the shell: Gas-phase solvation of halides by 1,3-butadiene

Gas-phase solvation of halides by 1,3-butadiene has been studied via a combination of photoelectron spectroscopy and density functional theory. Photoelectron spectra for X−⋯(C4H6)n (X=Cl, Br, I where n=1-3, 1–3 and 1–7 respectively) are presented. For all complexes, the calculated structures indicate that butadiene is bound in a bidentate fashion through hydrogen-bonding, with the chloride complex showing the greatest degree of stabilisation of the internal C−C rotation of cis-butadiene. In both Cl− and Br− complexes, the first solvation shell is shown to be at least n = 4 from the vertical detachment energies (VDEs), however for I−, increases in the VDE may suggest a metastable, partially filled, first solvation shell for n = 4 and a complete shell at n = 6. These results have implications for gas-phase clustering in atmospheric and extraterrestrial environments

Signatures of exciton coupling in paired nanoemitters

An exciton formed by the delocalized electronic excitation of paired nanoemitters is interpreted in terms of the electromagnetic emission of the pair and their mutual coupling with a photodetector. A formulation directly tailored for fluorescence detection is identified, giving results which are strongly dependent on geometry and selection rules. Signature symmetric and antisymmetric combinations are analyzed and their distinctive features identified

UNSW Énergie Renouvelable Vanuatu

Students and staff of the UNSW School of Photovoltaic and Renewable Energy Engineering,through UNSW Énergie Renouvelable Vanuatu (UNSWERV), have been undertakingrenewable energy education/development projects in Tanna Island, Vanuatu (pop. 29,000)since 2007. The projects have ranged from tiny stand-alone photovoltaic (PV) DC lighting andphone charging through lighting in schools to a hydro-powered village AC minigrid. Tanna is anisland with a small public grid, operated on behalf of the Government by a multinationalcompany, in the provincial capital of Lenakel/Isangel only. There is only a single hospital forthe island in the same town and the outlying villages are served by about seven dispensaries,with a trained nurse and operated by the Department of Health, and about twenty aid posts,owned and operated by the host village community. When we started our work, almost none ofthe dispensaries or aid posts had even basic lighting. This and next year, the dispensaries arebeing lighted by the Department’s contractor (PV, charge controller, battery, inverter and 240VAC LED lamps).The UNSW projects, previously in schools and dispensaries and, recently, primarily in aidposts and schools, have installed, exclusively, 12V DC systems, to take advantage of theinherent safety of extra low voltage and to avoid the unreliability of complex electronic invertersin harsh environments. Over the last decade the project has provided lighting and USB phonecharging to most of the dispensaries and seven aid posts. Limited lighting has also beenprovided in four schools, although Cyclone Pam in 2015 crippled two of the school projects andthe Imaki minigrid.In January and July 2018 two different groups of students installed basic lighting in seven aidposts around the island and a few rooms of a secondary school and carried out many repairsand minor upgrades to public facilities, while also planning several PV water pumping andlighting projects, surveying and planning the repair of the Imaki hydro minigrid and itsenhancement through the addition of 42 second hand PV modules donated in Sydney andshipped to Tanna in early 2018. In July the UNSW students trained a team of College de Imakiscience students and other community members to make reliable MC4-style connections forthe delivered modules in preparation for the intended installation in the minigrid. The team alsointends to revive the failed hydro turbine, despite the original model being withdrawn from themarket, by repairing the penstock, torn apart by the cyclone, and forming a reliable and stableweir at the intake point. Ambitions are limited only by funds, not by motivation or humanenergy.In a recent expansion of UNSWERV scope, the team is working with the dynamic communitybased around the continually active volcano, Mt. Yasur, a major tourist attraction, to exploitsome of the abundant geothermal energy available there. They need off-grid refrigeration forprovision of local, organic, natural drinks to tourists and thermal and electrical energy forproduction of other local products for the same market. UNSWERV is in discussion with aUNSW geothermal energy expert to support their aims

Solar Power User Guide for Vanuatu

Solar Power User Guide for Vanuatu (English and Bislama