Form-fit joining of hybrid busbars using a flexible tool demonstrator

This paper is focused on hybrid busbars made from copper and aluminum strips and presents a flexible tool demonstrator capable of replicating material flow in the lancing, bending and compression stages of a new joining by forming process without auxiliary elements. The flexible tool demonstrator is defined by its modular concept that allows the active tool components to be easily interchanged for testing and exploring different materials and thickness combinations, surface conditions and cross-section areas of the strips under laboratory conditions. Experimental and numerical simulation with a selected hybrid busbar geometry validates the overall concept and fabrication of the demonstrator and shows that the new joining by forming process can produce permanent form-fit joints with smooth upper and lower surfaces containing all the plastically deformed material within the thickness of the two strips. Complete filling of the free volume left in-between the thickness of the two strips allows obtaining an electric resistance lower than that of fastened hybrid busbars.

Effect of PCM fill ratio and heat sink orientation on the thermal management of transient power spikes in electronics

The goal of this paper is to investigate the usefulness of Phase Change Material based heat sinks in power surge operations. Experiments have been carried out on a PCM based heat sink for different fill ratios (0, 33, 66, and 99%) of the PCM and different orientations (0, 90, 180°) of the heat sink under constant and power surge heat loads. The heat sink with a fill ratio of 0% is considered as the baseline case for comparison. The heat sink with a fill ratio of 66% at 0° orientation recorded lower temperatures among all the fill ratios and orientations under both constant and power surge heat loads. Partial filling (66% fill ratio) of the PCM in the cavity is more effective than complete filling (99% fill ratio) in handling both constant and power surge heat loads.

Deletion of TRPV3 and CaV3.2 T-type channels in mice undermines fertility and Ca2+ homeostasis in oocytes and eggs

Calcium (Ca2+) influx during oocyte maturation and after sperm entry is necessary to fill the internal Ca2+ stores and for complete egg activation. We knocked out the transient receptor potential vanilloid member 3 (TRPV3) and the T-type channel, CaV3.2 to determine their necessity for maintaining these functions in mammalian oocytes/eggs. Double knockout (dKO) females were subfertile, their oocytes and eggs showed reduced internal Ca2+ stores, and following sperm entry or PLCz cRNA injection, fewer dKO eggs displayed Ca2+ responses compared to wildtype (WT) eggs, which were also of lower frequency. These parameters were rescued and/or enhanced by removing extracellular Mg2+, suggesting the residual Ca2+ influx could be mediated by the TRPM7 channel, consistent with the termination of divalent-cation oscillations in dKO eggs by a TRPM7 inhibitor. In total, we demonstrated that TRPV3 and CaV3.2 mediate the complete filling of the Ca2+ stores in mouse oocytes and eggs. We also show they are required for initiating and maintaining regularly spaced-out oscillations, suggesting that Ca2+ influx through PM ion channels dictates the periodicity and persistence of Ca2+ oscillations during mammalian fertilization.

A simplified formula for determination of relative pressure in the precision forging of spur gears

In this study, the relative forging pressures of spur gears were evaluated. The precision forging of spur gears was analyzed by using the upper bound method considering corner filling and bulging effect. Numerical and experimental studies were performed to investigate the effects of various parameters, such as the number of teeth, modules, facewidth, bore diameter, and friction factor on the relative forging pressure of spur gears. The results were compared with the previous studies and a simplified formula was suggested to predict the relative pressure of precision forging of spur gears. The predicted relative forging pressures obtained by the suggested formula are shown much closer to the experimental results for the complete filling of the die cavity.

Maxillary Sinus Mucopyocele: About an Endoscopic Management

Introduction: Mucocele is a benign but expansive cystic formation, lined by a respiratory epithelium. When its content is infected, it is called a mucopyocele. It usually develops in the frontal-ethmoid complex. The maxillary sinus location is exceptional. Case report: a 43 year old man, presented with chronic unilateral nasal obstruction, purulent rhinorrhea and anosmia. Rhinoscopy showed a bulge in the middle meatus. The computed tomography (CT) showed complete filling of the left maxillary with low-density mass. Magnetic resonance imaging (MRI) confirmed the diagnosis of mucpyeocele of the left maxillary sinus. Patient underwent endoscopic endonasal marsupialization with complete recovery. Conclusion: Mucopyocele of the maxillary sinus is a benign rare lesion, however destructive. A radiological assessment is essential to guide the choice of surgical treatment. The endonasal route remains the reference treatment for this pathology.

Enantioselective Study on the Biodegradation of Verapamil and Cytalopram by Chiral Capillary Electrophoresis

Many of the currently available drugs are chiral compounds that are marketed as racemates or, to a lesser extent, in the form of one of the enantiomers since a pair of enantiomers may have different toxicological and ecotoxicological properties compared to each other. The evaluation of enantioselectivity in biodegradation processes is essential for environmental risk assessment. The objective of this research is to study the enantioselectivity in the biodegradation of two common chiral drugs, citalopram and verapamil, using highly sulphated-γ-cyclodextrin (HS-γ-CD) as chiral selector in Capillary Electrophoresis. Biodegradation experiments were performed in batch mode using a minimal salt medium inoculated with an activated sludge and supplemented with the corresponding enantiomeric mixture. The cultures were incubated at 20 °C for 28 days. Abiotic degradation of verapamil and citalopram enantiomers was also assessed. The concentration of the enantiomers of verapamil and citalopram were monitored using 0.7% and 0.1% m/v HS-γ-CD solutions as chiral selector, respectively. Separations were carried out using the complete filling technique. The results of biodegradability tests indicate that citalopram could be considered potentially persistent while verapamil is presumed to be a non-persistent compound. No evidence of enantioselectivity was observed in any of the biodegradation processes.

Эволюция квантования Ландау спектра спинонных пар в слабом мотовском диэлектрике La-=SUB=-0.15-=/SUB=-Sm-=SUB=-0.85-=/SUB=-MnO-=SUB=-3+delta-=/SUB=- со спинонной поверхностью Ферми с ростом температуры и напряженности магнитного поля

Measurements of the magnetization temperature dependences of La0.15Sm0.85MnO3+δ in the temperature range 4.2 - 100 K revealed a threshold magnetization feature near the temperature Td 50 K, associated with the existence of a small pseudogap Δe in the electron spectrum, which is characteristic of a weak Mott dielectric. An increase in the strength H of the external magnetic field leads to suppression of the dielectric pseudogap Δe, an increase in the density of states of free charge/ spin carriers at EF, and transformation of the charge/spin density waves fragments. A quantization of the pairs spectrum of the low-energy magnetic excitations of a Z2 quantum spin liquid in the form of spinon-gauge field composite quasiparticles was found in the temperature range 4.2 - 12 K. Formation of a continuous spectrum of the quantum spin liquid excitations in the regime of “weak magnetic fields” Н = 100 Oe, 350 Oe, 1 kOe is explained within the framework of the Landau quantization models of the spectrum of composite quasiparticles with fractional values of the factor ν filling of three overlapping Landau zones.. In the regime of a “strong external magnetic field” H = 3.5 kOe, the new quantum oscillations of the temperature dependences of the magnetization of an incompressible spinon liquid were founded in the form of three narrow steps (plateaus) corresponding to the complete filling of non-overlapping Landau zones with integer values of the filling factor by spinons.

Risk Factors for Local Bone Destruction Progression in Palliative Percutaneous Vertebroplasty for Vertebral Metastases and the Significance of Bone Cement Filling Rates

BACKGROUND: For palliative percutaneous vertebroplasty (PVP) for vertebral metastases, local bone destruction progression (LBDP) commonly occurs in the previously treated vertebrae. There were no studies regarding LBDP and its risk factors in previous reports, and there was no uniform evaluation method for the distribution of bone cement in the vertebrae. OBJECTIVES: We aimed to investigate the risk factors for LBDP after PVP for palliative treatments in patients with vertebral metastases. We also proposed that filling rates could be used as a simple evaluation method to detect vertebral metastases and explored its clinical significance. STUDY DESIGN: This was a retrospective study. SETTING: A university hospital. METHODS: A total of 48 patients and 54 vertebrae that had received PVP as a palliative treatment for vertebral metastases were recruited between October 2012 to October 2019 from the Shengjing Hospital of the China Medical University. We collected and evaluated the data including age, gender, cement filled completely or not, cement dose used, the cement distribution score, time of LBDP, and so on, and the filing rate we proposed was also included. RESULTS: This retrospective study divided 48 patients and 54 vertebrae into group A for those with an LBDP of less than 6 months (n = 41), and group B for those with an LBDP of 6 or more months (n = 13). The complete filling of bone cement and bone cement dose in group B was much higher than that in group A (2.85 ± 0.97 vs. 4.12 ± 1.77; P = 0.027), and the time of recurrent pain in group B was significantly higher compared with that in group A (8.46 ± 2.73 vs. 3.39 ± 1.63; P < 0.0001). There was a statistical difference in the Saliou score and filling rate between the 2 groups (11.77 ± 3.17 vs. 9.34 ± 3.28, P = 0.023; 0.752 ± 0.227 vs. 0.489 ± 0.161, P < 0.0001). Univariate logistic analysis showed that complete filling of cement, the cement dose, Saliou score, and filling rate were statistically significant predictors of LBDP occurring in less than 6 months. Multivariate logistic analysis showed that the filling rate was an independent predictor of patients with vertebral metastases developing LBDP in less than 6 months (odds ratio, < 0.001; 95% confidence interval, < 0.001–0.006; P = 0.0007). The cutoff value for the filling rate calculated from the receiver operating characteristic (ROC) curve analysis was 0.646, which could identify patients who had LBDP in less than 6 months of PVP with a sensitivity of 85.4% and specificity of 84.6%. The 6-month LBDP in the 0.646 or less ROC curve group was higher than that in the greater than 0.646 ROC curve group (97.22% vs. 55.56%, P < 0.0001). LIMITATIONS: The retrospective nature and small sample size were significant. Variation in the time and state of bone cement injected during all PVP procedures was a bias. There was no pathological diagnosis of all vertebral metastases. CONCLUSIONS: The cement dose, complete filling of cement, Saliou score, and filling rate were factors negatively related to LBDP occurring in less than 6 months. Patients with lower filling rates are maybe more likely to have early LBDP compared with those with higher filling rates. KEY WORDS: Bone cement, distribution of bone cement, local bone destruction progression, percutaneous vertebroplasty, palliative treatment, vertebral metastases

The Filling Evaluation of Lateral Canals in the Root Canal Obturation

A complexidade anatômica dos canais radiculares, por exemplo, sua forma, curvatura e diversidade da curvatura do raio, bem como a presença de istmo de alto índice e canais laterais, são fatores importantes a serem levados em consideração na terapia endodôntica. Assim, o objetivo neste estudo foi avaliar o preenchimento total de canais laterais simulados com dois diferentes cimentos endodônticos. Foram utilizados 8 dentes anteriores extraídos por razões periodontais. Foram confeccionados canais laterais com uma broca carbide esférica ¼ a uma distância de 4 mm do ápice radicular. Em seguida, os dentes foram radiografados no sentido anteroposterior. Os canais radiculares destes dentes foram preparados utilizando-se de um sistema reciprocante 25.08 acionados por motor elétrico X Smart Plus até o comprimento de trabalho utilizando hipoclorito de sódio 2,5% como solução irrigante. Os dentes foram divididos em 2 grupos (n=4) de acordo com diferentes cimentos endodônticos (AH Plus ou Bio C Sealer). Os canais foram secos com pontas de papel absorvente, depois foram preenchidos com cone médio e diferentes cimentos endodônticos. O preenchimento total de canais laterais simulados foram avaliados a partir de novas radiografias digitais realizadas após obturação dos dentes. Os canais laterais simulados não foram completamente preenchidos, independentemente do cimento endodôntico utilizado, e os resultados demonstraram que os diferentes cimentos avaliados não preencheram os canais radiculares laterais simulados. Palavras-chave: Endodontia. Obturação do Canal Radicular. Materiais Restauradores do Canal Radicular. Abstract The anatomical complexity of root canals, for instance, their shape, curvature and radius curvature diversity, as well as the presence of high index isthmus and lateral canals are important factors to be taken into consideration in endodontic therapy. Thus, the aim of the present study was to assess complete filling of simulated lateral canals with two different endodontic cements. Eight anterior teeth extracted due to periodontal reasons were used in the experiment. Lateral canals were opened with ¼ spherical-shaped carbide drill 4 mm away from the root apex. Teeth were subjected to X-ray in anteroposterior position. The root canals of these teeth were prepared with the aid of a 25.08 reciprocating system in electrically driven motor X Smart Plus for its working length by using 2.5% sodium hypochlorite as irrigating solution. The teeth were divided into 2 groups (n=4) according to different endodontic cements (AH Plus or Bio C Sealer). Root canals were dried with paper points, afterwards were filling with medium cone and different endodontic cements. The complete filling of simulated lateral canals was assessed based on new digital radiographs taken after teeth filling. The simulated lateral canals were not completely filled, regardless of the used endodontic cement. Results have shown that the different assessed cements did not fill the simulated lateral root canals. Keywords: Endodontics. Root Canal Filling. Root Canal Sealer Materials.