A geographic information method for managing urban energy use

This paper presents a geographical information method to support urban-level energy policies. It proposes using a geographical information system to store, display, edit, share and analyse geographical information for territorial decision-making. The method was used to help develop a sustainable energy action plan for the municipality of Randazzo in Sicily, Italy, by providing an accurate representation of actual energy consumption. Based on this case study, the use of a geographical information system appears to be a suitable support tool for both developing and managing sustainable energy action plans, regardless of the geographical area or context. This method will help municipalities estimate and monitor the energy consumption of residential, commercial and industrial buildings and, by taking into account the approaches of different stakeholders, help develop more accurate models for reducing urban carbon dioxide emissions

Forecasting Solar Home System Customers’ Electricity Usage with a 3D Convolutional Neural Network to Improve Energy Access

Off-grid technologies, such as solar home systems (SHS), offer the opportunity to alleviate global energy poverty, providing a cost-effective alternative to an electricity grid connection. However, there is a paucity of high-quality SHS electricity usage data and thus a limited understanding of consumers’ past and future usage patterns. This study addresses this gap by providing a rare large-scale analysis of real-time energy consumption data for SHS customers (n = 63,299) in Rwanda. Our results show that 70% of SHS users’ electricity usage decreased a year after their SHS was installed. This paper is novel in its application of a three-dimensional convolutional neural network (CNN) architecture for electricity load forecasting using time series data. It also marks the first time a CNN was used to predict SHS customers’ electricity consumption. The model forecasts individual households’ usage 24 h and seven days ahead, as well as an average week across the next three months. The last scenario derived the best performance with a mean squared error of 0.369. SHS companies could use these predictions to offer a tailored service to customers, including providing feedback information on their likely future usage and expenditure. The CNN could also aid load balancing for SHS based microgrids

Theory and it ab initio calculation of radiative lifetime of excitons in semiconducting carbon nanotubes

We present theoretical analysis and first-principles calculation of the radiative lifetime of excitons in semiconducting carbon nanotubes. An intrinsic lifetime of the order of 10 ps is computed for the lowest optically active bright excitons. The intrinsic lifetime is however a rapid increasing function of the exciton momentum. Moreover, the electronic structure of the nanotubes dictates the existence of dark excitons nearby in energy to each bright exciton. Both effects strongly influence measured lifetime. Assuming a thermal occupation of bright and dark exciton bands, we find an effective lifetime of the order of 10 ns at room temperature, in good accord with recent experiments.Comment: 12 pages, 3 figure

Temperature Dependence of the Band Gap of Semiconducting Carbon Nanotubes

The temperature dependence of the band gap of semiconducting single-wall carbon nanotubes (SWNTs) is calculated by direct evaluation of electron-phonon couplings within a ``frozen-phonon'' scheme. An interesting diameter and chirality dependence of $E_g(T)$ is obtained, including non-monotonic behavior for certain tubes and distinct ``family'' behavior. These results are traced to a strong and complex coupling between band-edge states and the lowest-energy optical phonon modes in SWNTs. The $E_g(T)$ curves are modeled by an analytic function with diameter and chirality dependent parameters; these provide a valuable guide for systematic estimates of $E_g(T)$ for any given SWNT. Magnitudes of the temperature shifts at 300 K are smaller than 12 meV and should not affect $(n,m)$ assignments based on optical measurements.Comment: To appear in Phys. Rev. Let

Exciton-plasmon states in nanoscale materials: breakdown of the Tamm-Dancoff approximation

Within the Tamm-Dancoff approximation ab initio approaches describe excitons as packets of electron-hole pairs propagating only forward in time. However, we show that in nanoscale materials excitons and plasmons hybridize, creating exciton--plasmon states where the electron-hole pairs oscillate back and forth in time. Then, as exemplified by the trans-azobenzene molecule and carbon nanotubes, the Tamm-Dancoff approximation yields errors as large as the accuracy claimed in ab initio calculations. Instead, we propose a general and efficient approach that avoids the Tamm--Dancoff approximation, and correctly describes excitons, plasmons and exciton-plasmon states

Colon intussusception treated endoscopically (case report)

Secția endoscopie, Institutul Medicinei de Urgență, Chișinău, Republica Moldova, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Caz clinic: În Clinică la 30 octombrie 2013 s-a adresat pacientul SA de 19 ani, cu acuze la dureri intense în flancul stîng, vomă repetată cu conținut gastric, astenie pronunțată, inapetență, lipsa scaunului (2 zile), lipsa emisiei de gaze (24 ore). Din anamneză, în copilărie – diagnosticat cu megacolon congenital, părinții au refuzat tratamentul chirurgical. La internare: abdomenul moderat balonat, simetric, dolor intens la palpare în flancul stîng și mezogastru, semne peritoneale – absente, per rectum – conținut intestinal, pereții – dilatați. Spitalizat cu diagnosticul de ocluzie intestinală joasă. Ecografia cavității abdominale a evidențiat un minim de lichid liber interileal. Radiografia abdomenului – aerocolie pronunțată. La 31 octombrie 2013 s-a efectuat colonoscopie pînă la flexura lienală, înaintarea fiind neinformativă (în lumen – materii fecale). În sigmoid, la distanța 25 cm de la orificiul anal pînă la 40 cm, peretele intestinului nu se reexpansiona complet, mucoasa – edemațiată, culoare violacee, cu peteșii hemoragice. Lumenul colonului nu se vizualiza. La insuflarea aerului porțiunea proximală de perete intestinal a glisat, eliberînd lumenul sigmoidului. Colonul descendent examenat – mărit în dimensiuni atît longitudinal cît și transversal. Mucoasa examinată subțiată, cu desen vascular pronunțat. Haustrele intestinale – absente. Peristaltismul intestinal – absent. Unghiul lienal – permeabil. Biopsia din mucoasa schimbată macroscopic al sigmoidului nu a fost prelevată din cauza pericolului hemoragiei și a perforației. La pacient s-a constatat o invaginație de colon la nivelul sigmoidului, megadolicocolon. După colonoscopie starea generală a pacientului s-a ameliorat, acesta fiind externat din staționar recomandîndu-se tratamentul chirurgical programat al dolicocolonului.Clinical case: This article reports a clinical case of intestinal obstruction intussusception, which was solved by colonoscopy. A 19-years-old patient was admitted on October 30, 2013 to the Hospital with the following complaints: severe pain in left abdominal flank, repeated vomiting, pronounced asthenia, decreased appetite, constipation and a lack of gas (2 days). In anamnesis, childhood-diagnosed with congenital megadolichocolon, parents refused surgical treatment. Physical exam: the swollen abdomen, abdominal pain on palpation, no peritoneal signs. Hospitalized with intestinal obstruction. Abdomenal cavity ultrasound showed minimal free liquid. X-rays of the abdomen showed a bowel distension. October 31, 2013 was conducted colonoscopy. In the sigmoid, at a distance of 25 cm from the anus, up to 40 cm, the intestinal wall was not deployed fully, the swelling, purple mucous with petechial hemorrhages. The lumen of the colon was not see. Under the inspiration of the air, the proximal portion of the intestinal wall, to drag it, giving the lumen of the sigmoid. Colon descending seen, increased in size, both lengthwise and transversely. Mucous were narrowed, with strikes pronounced. The folds of the intestine absented. Peristalsis was absent. No biopsy was taken of the macroscopic changed mucous of sigmoid, because of the risk of bleeding and perforation. The patient was found to intussusception of the colon sigmoid. After the colonoscopy the general condition of the patient improved, was discharged from the hospital and it was recommended surgical treatment of dolichocolon

Fano resonances in a three-terminal nanodevice

The electron transport through a quantum sphere with three one-dimensional wires attached to it is investigated. An explicit form for the transmission coefficient as a function of the electron energy is found from the first principles. The asymmetric Fano resonances are detected in transmission of the system. The collapse of the resonances is shown to appear under certain conditions. A two-terminal nanodevice with an additional gate lead is studied using the developed approach. Additional resonances and minima of transmission are indicated in the device.Comment: 11 pages, 5 figures, 2 equations are added, misprints in 5 equations are removed, published in Journal of Physics: Condensed Matte