Communication-based Adaptive Protection for Distribution Systems Penetrated with Distributed Generators

In this article, a communication-based adaptive over-current protection scheme for distribution systems penetrated with distributed generators is proposed. A communication network between the over-current relays, the distributed generators, and the utility grid is employed to automatically update the settings of the protective relays. Moreover, the communication reliability is increased through the addition of a backup communication system. The proposed scheme has the advantage of operating during grid-connected and islanding modes of operation. The scheme employs two simultaneous algorithms. The first algorithm works when the system configuration is changed due to the connection/disconnection of a distributed generator or the utility grid. The second algorithm efficiently uses the exchanged information between the relays to identify the faulted section and hence speeds up fault clearance. The proposed scheme is tested for difierent fault conditions as well as for different system configurations. The results demonstrated that relay operating times, including the communication delay, are greatly reduced when the faulted section is identified and relay settings are adjusted accordingly. In addition, a negligible time delay was experienced when the backup communication network was put in service.     

Sequential Template Decomposition to Adjust the Performance of Imperfect Zeolite BEA Membranes

Zeolite membranes offer superior thermal, chemical, and mechanical stability compared to polymeric membranes. However, it is still a challenge to prepare completely defect‐free membranes without any intercrystalline voids, which is necessary for gas separation processes. In this study zeolite beta (*BEA) membranes on stainless‐steel supports were prepared by applying the multiple in situ crystallization technique. The membranes were used as a model system to systematically study the decomposition of the organic structure directing agent tetraethylammoniumhydroxide (TEA‐OH). It was evaluated if the organic decomposition products of TEA‐OH can be used for enhancing the membranes selectivity. Post‐treatment experiments have been carried out to adjust surface properties and pore size dimensions in the zeolitic membrane layer. The results show that membranes calcined at lower temperatures exhibit a higher gas selectivity.     

A Model of Drying Kinetics of Acacia mangium Wood at Different Temperatures

The objective of this study was to determine the isothermal drying kinetics of Acacia mangium wood blocks by employing a relative humidity-controlled drying chamber. A model was developed based on solution of Fick's second law and evaluated through the coefficient of determination (R ² ), sum of square error (SSE), root mean square error (RMSE), and reduced chi-square (χ ² ). This model was compared to semi-theoretical models which are commonly used to describe the drying behavior of biomass in previous studies. The porosity and shrinkage characteristics of dried specimens were also evaluated. Based on the findings in this work, it was determined that the proposed model resulted in an excellent fit with experimental data for all four drying temperature levels of 30, 35, 40, and 45 ^° C to describe the isothermal drying kinetics of Acacia mangium . It appears that volumetric shrinkage of the samples decreased quadratically with decreasing moisture ratio. The activation energy of the drying process was determined to be 41.07 kJ/mol.     

The neuropathy of Dejerine and Sottas: report of an Indian family

We report a case of metastatic insular carcinoma of the thyroid evaluated with 201TI, 99mTc-MIBI, 99mTc-(V)DMSA, 99mTc-MDP and 131I whole-body scans, which were obtained after total thyroidectomy. For the majority of lesions detected in the skeleton and soft tissue, 131I images were generally available, although most were visualized easier with 99mTc-(V)DMSA. Technetium-99m-MDP images were considered better than 99mTc-(V)DMSA images in showing bone lesions but not soft-tissue lesions. Both 201TI and 99mTc-MIBI scans provided sufficient advantage to exhibit neck and mediastinal metastases, but they did not surpass 99mTc-(V)DMSA in detecting abdominal or bony lesions. In this patient with various metastases from insular carcinoma of the thyroid, 99mTc-(V)DMSA seemed to be the tracer of choice for whole-body imaging.     

Laparoscopic surgery in a small animal model. A simplified technique of retroperitoneal dissection in the rat

BACKGROUND: An adequate laparoscopic small-animal model would benefit surgical oncologic research. Immunobiologic data and reagents available for the rodent make them an ideal species. We developed a simple, inexpensive, reproducible technique for laparoscopic surgery in rodents. METHODS: Carbon dioxide pneumoperitoneum is achieved in anesthetized animals. Through a 0.5-cm midline incision a 4.8-mm bronchofiberscope is inserted into the peritoneal cavity and secured with a purse-string suture (PSS). Three additional PSSs are made to introduce the dissectors. Under fiberscopic vision, a blunt dissection of the retroperitoneum exposes the inferior vena cava and aorta. Necropsy 24 h after verifies the adequacy of dissection. RESULTS: Eighteen animals survived. The only death resulted from bleeding. Mortality was 5.26%. Surgical time was 24.72 +/- 8.93 min with all animals active 2 h postlaparoscopy. CONCLUSIONS: Laparoscopic surgery (LS) can be done inexpensively without sophisticated equipment. The rodent is ideal for examining the immunologic consequences of laparoscopic surgery and pneumoperitoneum.     

Electrospun Fiber-Coated Human Amniotic Membrane: A Potential Angioinductive Scaffold for Ischemic Tissue Repair

Cardiac patch implantation helps maximize the paracrine function of grafted cells and serves as a reservoir of soluble proangiogenic factors required for the neovascularization of infarcted hearts. We have previously fabricated a cardiac patch, EF-HAM, composed of a human amniotic membrane (HAM) coated with aligned PLGA electrospun fibers (EF). In this study, we aimed to evaluate the biocompatibility and angiogenic effects of EF-HAM scaffolds with varying fiber thicknesses on the paracrine behavior of skeletal muscle cells (SkM). Conditioned media (CM) obtained from SkM-seeded HAM and EF-HAM scaffolds were subjected to multiplex analysis of angiogenic factors and tested on HUVECs for endothelial cell viability, migration, and tube formation analyses. All three different groups of EF-HAM scaffolds demonstrated excellent biocompatibility with SkM. CM derived from SkM-seeded EF-HAM 7 min scaffolds contained significantly elevated levels of proangiogenic factors, including angiopoietin-1, IL-8, and VEGF-C compared to plain CM, which was obtained from SkM cultured on the plain surface. CM obtained from all SkM-seeded EF-HAM scaffolds significantly increased the viability of HUVECs compared to plain CM after five days of culture. However, only EF-HAM 7 min CM induced a higher migration capacity in HUVECs and formed a longer and more elaborate capillary-like network on Matrigel compared with plain CM. Surface roughness and wettability of EF-HAM 7 min scaffolds might have influenced the proportion of skeletal myoblasts and fibroblasts growing on the scaffolds and subsequently potentiated the angiogenic paracrine function of SkM. This study demonstrated the angioinductive properties of EF-HAM composite scaffold and its potential applications in the repair and regeneration of ischemic tissues.     

Graphene oxide-coated microbottle resonators for relative humidity sensing

Graphene oxide (GO) is a 2D coating material used to improve fiber optics sensors’ response to relative humidity. Microbottle resonators (MBRs) have garnered more attention as sensing media structures. An MBR with a 190 µm diameter was coated with GO. Then, tapered fiber light coupling was used to investigate the relative humidity sensing performance in the range of 35—70%RH at 25 °C. The MBR showed a higher Q factor before and after GO coating. The sensitivity of 0.115 dB/%RH was recorded with the 190 µm GO-coated MBR sample compared to a sensitivity of 0.022 dB/%RH for the uncoated MBR sample. These results show that the MBR can be used in fiber optic sensing applications for environmental sensing.     

Q-switched giant pulsed erbium-doped all-fiber laser withV2ZnC MAX phase saturable absorber

MXenes, drawn from MAX phases, are special two-dimensional substances with numerous advantages in nonlinear optics, specifically in giant and ultrashort pulsed-laser applications. Ti3C2Tx and Ti2CTx nanosheets however rapidly deteriorate under ambient conditions, limiting their applications. This paper demonstrates how excellent modulation depth of one of the MAX phase compounds vanadium zinc carbide (V2ZnC) makes it a brilliant saturable absorber (SA) in passively Q-switched all-fiber pulsed lasers, integrated such that a 16.73-µm V2ZnC-polyvinyl alcohol (PVA) thin film acts as SA in the laser. Saturable and non-saturable absorptions were found to be 13.2% and 10.47%, while saturation optical intensity and modulation depth were 6.25 kW/cm2 and 12.43%, respectively, illustrating the optical nonlinearity. The superiority of MAX-PVA, fabricated in four distinct ratios, was demonstrated by the fact that it self-starts a giant pulsed laser at pump power as low as 22.5 mW and firmly accomplished 120.6 kHz repetition rate with a pulse width of 2.08 µs. It is a fine SA for the use of pulsed-laser production using all-fiber laser due to fabrication simplicity and great optical, thermophysical, and mechanical qualities.     

Effect of CdCl2 treatment on physical properties of CdTe films with different compositions fabricated by chemical molecular beam deposition

CdTe films with different compositions (Cd-rich, Te-rich and stoichiometric) were fabricated by revolutionary novel and low cost chemical molecular beam deposition (CMBD) method in the atmospheric pressure hydrogen flow. Cd and Te granules were used as precursors. The films were deposited on ceramic (SiO₂: Al₂O₃) substrates at 600°C. The growth rate was varied in the range of 20–30 Å/s. The composition of the samples was changed by controlling the molecular beam intensity (MBI) ratio Cd/Te. Effect of CdCl₂ treatment on morphology, photoluminescence and electrical properties of CdTe films was investigated by AFM, Raman, photoluminescence (PL) and Hall methods.     

Physics students' conceptions of energy and technological development in energy

There has been strong international interest in students' understanding concerning phenomenon taught in physics. Many studies have been conducted to find out students' conceptions in various concepts in physics. This study was designed to find out students' conceptions of the relationship of energy use and technological development in energy. It was conducted by administering a questionnaire to 133 first year physics students at a university. A questionnaire entitled “Questionnaire On Energy And Technological Development” was used to collect data for this study. The results were analyzed to identify students' conceptions on energy use and technological development in energy. Finally, implications on teaching of energy is discussed in this paper.