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

Antibiotic resistance/sensitivity of the purulent septic nosocomial infections in hospitals of orthopedic and traumatological profile

The study describes the antibiotic resistance of causative agents of purulent septic infections in patients of hospitals of ortopedic and traumatological profile. It includes 1269 patients from whom 2013 strains of microorganisms have been isolated. As a result of the analysis of antibiograms, a high resistance of strains to antibiotics have been detected (50.16%), including gram-negative microorganisms – 57.72% and gram-positive ones – 46.09%. A high level of antibiotic resistance has been identified in such microorganisms as Acinetobacter (85.72%), E. cloacae (71.43%), C. diversus (64.78%), K. pneumoniae (64.54%) and P. aeruginosa (62.78%). Depending on the antibiotic group, a higher resistance of these strains to penicillins (63.95%), cephalosporins (66.15%) and, especially, to the third generation of cephalosporins (69.35%) has been detected. Purulent septic pathology in hospitals of ortopedic and traumatological profile is of poly-etiologic nature and characterized by a high resistance of the pathogen agents to antibiotics. At the same time, the sensitivity/resistance of the causative agents is very diverse, the values of which, depending on the group of antibiotics, are from 29.0 to 97.0% – sensitive, and vice versa, from 26.0 up to 98.0% – resistant. A high resistance to antibiotics has been established in gram-negative microorganisms (57.72%), including Acinetobacter (85.72%), E. cloacae (free 71.43%), C. diversus (64.78%), K. pneumoniae (64.54%), P. aeruginosa (62.78%), in particular, to penicillins and cephalosporins, the antibiotics widely used in medical practice. The results of the study demonstrate the need for the development and implementation of the programme on surveillance and control of microbial antibiotic resistance suitable to a medical hospital

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

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

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

An Accurate Physical Model for PV Modules with Improved Approximations of Series-Shunt Resistances

© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.An accurate model to represent the photovoltaic modules is essential to facilitate the efficient deployment of these systems in terms of design, analysis, and monitoring considerations. In this respect, this study proposes a new approach to improve the accuracy of the widely used five-parameter single-diode model. Two new physical equations are introduced to represent the series and shunt resistances, while the other parameters are represented by well established physical expressions. In the proposed model, most of the parameters are in terms of the cell temperature, irradiance, and datasheet values, while a few parameters need to be tuned. The model is compared with four well-known methodologies to extract the parameters of the single-diode and double-diode models. The simulation studies make use of the different I-V characteristics provided in the photovoltaics (PVs) datasheets, characteristics extracted from an outdoor module, as well as the ones simulated with the software PC1D. The results show an improved precision of the proposed model to estimate the power characteristics for a wide range of temperatures and irradiances, not only in the maximum power point but also in the whole range of voltages. Furthermore, the proposed physical model can be easily applied to other kind of studies where a physical meaning of the PV parameters is of great importance.Peer ReviewedPostprint (author's final draft

Laparoscopic management of associated abdominal complications of ventriculoperitoneal shunt

Catedra de chirurgie nr. 1 „Nicolae Anestiadi”, Laboratorul de chirurgie hepato-pancreato-biliară, USMF „Nicolae Testemițanu”, IMSP Institutul de Medicină Urgentă, Chișinău, Republica Moldova, Conferința stiințifică „Nicolae Anestiadi – nume etern al chirurgiei basarabene” consacrată centenarului de la nașterea profesorului Nicolae Anestiadi 26 august 2016Introducere. Complicaţiile abdominale ale şuntării ventriculoperitoneale (VP) sunt descrise în 5–47% cazuri. Pseudochistul abdominal cu lichid cerebrospinal este o complicaţie rară a şuntului VP, majoritatea fiind descrise la copii. Pseudochistul abdominal şi migrarea intraabdominală a cateterului sunt rare la pacienţii adulţi. Ocluzia şuntului VP sau nefuncţionarea acestuia induc presiune intracraniană sporită, fiind o indicaţie pentru intervenţie de urgenţă. Metode. Prezentare de caz clinic. Rezultate. Autorii prezintă un caz de tratament reuşit al unui pseudochist abdominal cu lichid cerebrospinal combinat cu migrarea cateterului intraabdominal rupt, la 9 ani după instalarea şuntului VP pentru hidrocefalie la o pacientă de 20 ani. Concluzii. Abordul laparoscopic este sigur şi util pentru tratamentul complicaţiilor combinate ale şuntului VP.Introduction. Abdominal complications after ventriculoperitoneal (VP) shunt placement are reported in 5–47% of cases. Abdominal cerebrospinal fluid (CSF) pseudocyst is an uncommon complication of a VP shunt, the majority being reported in children. Abdominal pseudocysts and intra-abdominal catheter migration are rare in adult patients. Ventriculoperitoneal shunt obstruction or malfunction results in elevated intracranial pressure, representing an indication for immediate intervention. Methods. Case report. Results. The authors report a case of successful laparoscopic management in a 20-year-old female patient who developed CSF pseudocyst combined with migration of the fractured catheter in the abdominal cavity nine years after VP shunting for hydrocephalus. Conclusions. Laparoscopic approach is a safe and useful treatment modality for combined peritoneal complications of VP shunt

Excitonic Effects on Optical Absorption Spectra of Doped Graphene

We have performed first-principles calculations to study optical absorption spectra of doped graphene with many-electron effects included. Both self-energy corrections and electron-hole interactions are reduced due to the enhanced screening in doped graphene. However, self-energy corrections and excitonic effects nearly cancel each other, making the prominent optical absorption peak fixed around 4.5 eV under different doping conditions. On the other hand, an unexpected increase of the optical absorbance is observed within the infrared and visible-light frequency regime (1 ~ 3 eV). Our analysis shows that a combining effect from the band filling and electron-hole interactions results in such an enhanced excitonic effect on the optical absorption. These unique variations of the optical absorption of doped graphene are of importance to understand relevant experiments and design optoelectronic applications.Comment: 15 pages, 5 figures; Nano Lett., Article ASAP (2011

Intersubband decay of 1-D exciton resonances in carbon nanotubes

We have studied intersubband decay of E22 excitons in semiconducting carbon nanotubes experimentally and theoretically. Photoluminescence excitation line widths of semiconducting nanotubes with chiral indicess (n, m) can be mapped onto a connectivity grid with curves of constant (n-m) and (2n+m). Moreover, the global behavior of E22 linewidths is best characterized by a strong increase with energy irrespective of their (n-m) mod(3)= \pm 1 family affiliation. Solution of the Bethe-Salpeter equations shows that the E22 linewidths are dominated by phonon assisted coupling to higher momentum states of the E11 and E12 exciton bands. The calculations also suggest that the branching ratio for decay into exciton bands vs free carrier bands, respectively is about 10:1.Comment: 4 pages, 4 figure

Diversity of mini-invasive surgery in the Central military hospital of the National army

Spitalul Clinic Militar Central al Armatei Naționale, Chişinău, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Actualitatea temei: Tratamentul patologiilor chirurgicale a suferit unele modificări legate de timp. Factorul esențial care a influențat acest eveniment a fost progresul tehnico-ştiințific cu introducerea video chirurgiei în procedeele chirurgicale şi instruirea specialiştilor din chirurgia generală. Ca rezultat a acestei îmbinări a profitat chirurgia miniinvazivă (laparoscopică/endoscopică). Materiale şi metode: În articol este prezentată evoluția chirurgiei miniinvazive ce include operații miniinvazive: laparoscopice/endoscopice în secția chirurgie generală a SCMC între 2008- 2011. Intervențiile chirurgicale au fost efectuate cu setul de video-chirurgie, utilizat pentru patologia chirurgicală a organelor interne, pentru patologia urologică şi ginecologică. Rezultate obținute:În acesată perioadă de timp au fost efectuate 730 operații miniinvazive, (laparoscopice/endoscopice): Colecistectomii 446(61,8%), apendicectomii 12(1,6%), hernii hiatale 19(2,7%), hernii inghinale 60 (8,2%), hernii ombilicale 3(0,4%), tratarea laparoscopică a varicocelului-clamparea venei testiculare 43(5,9%), chistovarectomii, 25(3,4%) chistectomii hidatice 13(1,8%), clamparea endoscopică subfascială a venelor perforante 3(0,4%), rezecție transuretrală a adenomului de prostată 47(6,5%),laparoscopii diagnostice curative 59(8,1%). Durata medie de spitalizare a acestor bolnavi a fost 5 zile. Raportul bărbați, femei a fost 3:1. Vîrsta pacienților a fost de la 18 ani pînă la 82 ani. Decese şi complicații severe caracteristice pentru chirurgia laparoscopică/endoscopică nu sau înregistrat. S-au evidențiat unele particularități. Conversii la operații tradiționale au fost în 6 cazuri. La colecistectomia tradițională în 5 cazuri de colecistită acută cu anatomie dificilă de identificare a elementelor triunghiului Calot procese distructive avansate. Un caz de hernie laparoscopică pentru hernie inghinală prin alunecare a vezicii urinare. Concluzii: 1. Experiența noastră în chirurgia miniinvazivă, denotă că rezultatele obținute sunt într-o legătură strînsă dintre înzestrarea secției cu echipament necesar şi experiența acumulată pe parcursul anilor.Novelty: Treatment of surgical pathologies has undergone some modifications related to time. The key factor that influenced this phenomenon was the scientific and technical progress, namely introduction of video surgery in surgical procedures and training of specialists in general surgery. Minimally invasive surgery (laparoscopic / endoscopic) as a result took advantage of this combination. Materials and methods: The article presents the evolution of mini-invasive surgery including mini- invasive surgical interventions: laparoscopic / endoscopic ones in the Department of General Surgery of SCMC between 2008 to 2011. Surgeries were performed by means of the video-surgery kit, used for surgical pathology of the internal organs, for urological and gynecological pathologies. Results: Within this period 730 mini - invasive surgical interventions, (laparoscopic / endoscopic ones) were performed: 446 cholecystectomies (61.8%), apendicectomies 12 (1.6%), hiatal hernias 19 (2.7%), inguinal hernias 60 (8.2%), umbilical hernias 3 (0.4%), laparoscopic treatment of varicocele, testicular vein clipping 43 (5.9%), cystovarectomies, 25 (3.4%) hydatid cystectomies 13 (1.8%), endoscopic subfascial clipping of the perforated veins 3 (0.4%), transurethral resection of the prostate adenoma 47 (6.5%), diagnostic curative laparoscopies 59 (8.1%). The mean duration of the patients hospitalization was 5 days. The proportion of men and women was 3:1. The age of patients was from 18 years to 82 years. Deaths and complications characteristic of laparoscopic/ endoscopic surgery were not registered. Some peculiarities have been revealed. Conversions to traditional operations were in 6 cases. In 5 cases the traditional cholecystectomy of acute cholecystitis with difficulty to identify anatomical features of Calot triangle revealed advanced destructive processes. A case of laparoscopic hernia in inguinal hernia through sliding of the bladder was recorded. Conclusions: Our experience in minimally invasive surgery, shows that the obtained results are in a close relationship with use of the necessary surgical equipment and professional experience gained over the years