The Marangoni effect and translation of free non-deformable drops

A model is presented for flow caused by interface tension gradients, the so called Marangoni effect, on a free, nondeformable drop. A free drop, initially at rest, undergoes a translation motion upon the action of surface flow. The experiments carried out by injecting a drop with surfactants, which induce an interface tension gradient, are in good agreement with the theoretical model proposed

Molecular Dynamics and Vibrational Analysis of Pentacene: RHF and DFT Study

The molecular dynamics of Pentacene molecule and its vibrational behavior is studied using the Gaussian software at the Restricted Hartree Fock and Density Functional Theory levels of computation. Two medium size basis sets, 6-31G and 6-31G* are used. The dipole moments, thermal energies and band gap computations for the molecule are obtained. The Infra Red (IR) and Raman vibrational frequencies are vividly examined and the most intense IR and Raman frequencies identified. The computed band gap at DFT level of theory for both basis sets is much in agreement with the experimental value. Keywords: Pentacene,  Hartree-fork, DFT, bond-angle, bondlength, Raman, frequencie

RHF and DFT study of the optimized molecular structure and atomic charge distribution of pentacene

Restricted HartreeFock (RHF) and Density Functional Theory (DFT) studies were carried out on the organic semi conductor material Pentacene. 6-31G and 6-31G* basis sets were used to optimize the molecule and compute the charge distribution at both levels of theory. The results show that the Carbon-Hydrogen bonds in the molecule are the shortest and strongest with average bond length of 1 Å. The C-C bonds were the longest and weakest. On the average the bond angles were all above 90 degrees, giving the molecule a fairly symmetric structure. The bulk positive charges in Pentacene were predicted to reside mostly in the Hydrogen atoms and the Carbon atoms were averagely electronegative in this molecule

Evaluation of Heavy Metal Concentration in Drinking Water Collected from Local Wells and Boreholes of Dutse Town, North West, Nigeria

Water samples collected from Dutse Town, Jigawa State, were studied and analyzed for heavy metals. A total of 48 samples were collected from 24 different sampling sites in Dutse town namely: FUD, Gidan Dubu Yadi, Bakwato 1, Bakwato 2, Tashar Danwake, Fatara, Kargo, Garu/Emir palace, Fagoji 1, Fagoji 2, Zai, Jigawa Sarki, Kachi, Limawa, Galamawa, Dasina, Takur Adua, Jigawar Tsada, Takur Site, Dan Masara, Mopol Base, G-9 Site and Aminu Kano Way/Cikin Gari. The samples were studied and analyzed for eight (8) heavy metals namely; Cadmium (Cd), Cobalt (Co), Copper (Cu), Iron (Fe), Manganese (Mn), Lead (Pb), Mercury (Hg) and Nickel (Ni). The results obtained were compared with the international standards. The samples were analyzed at the Central Laboratory, Ahmadu Bello University, Zaria. Atomic Absorption Spectrometer (AAS) was used in this study and the average concentration of these heavy metals  are 0.0034, 0.0409, 0.0151, 1.8241, 0.01471, 0.2731, 2.2829 and 0.0433 mg/l for Cd, Co, Cu, Fe, Pb, Mn, Hg and Ni respectively. Among the analyzed heavy metals, Cd, Co, Cu and Ni were below the recommended level set by United State Environmental Protection Agency (USEPA) and World Health Organization (WHO) while Fe, Pb, Mn and Hg were higher than the recommended level set by USEPA and WHO for safe drinking water. This imply that the water collected from these sampling areas were contaminated with heavy metals which may have serious health hazard to the people using such water for drinking and other domestic activities. Keywords: Heavy metals, Wells, Boreholes, Drinking Water, Dutse Tow

Characterization of some Nigerian coal for effective power generation and industrial utility

Large numbers of trace elements occur in coals used for coal power plants combustion. In order to assess the environmental impact of the coal fuel cycle, coal and coal ash samples need to be analyzed for a number of toxic and radioactive elements. Six coal samples from Ridi-Awe and Lafia (Nasarawa State), Garin Maiganga (Gombe state) Nigeria coal deposit were collected. The samples were subjected to gross calorific value determination, X-ray diffraction spectrometry, X-ray fluorescence spectroscopy to determine it suitability for power generation and industrial utility. Base on the laboratory analysis and results, it is observed that the gross calorific values of Awe are 29.18MJ/kg, 30.79MJ/kg. Lafia are 26.10MJ/kg, 25.10MJ/kg and Maiganga are 25.50MJ/kg, 24.21MJ/kg respectively. The XRF results indicates the presence of transition metals and some trace element but void of elements such as Arsenic, tin and tungsten which makes it environmental and health hazard friendly. The proximate analysis revealed that the % ash content of Awe, Lafia, and Maiganga is 87, 62, 79. % moisture content of Awe, Lafia, and Maiganga is 8.7, 16.3, 8.3 and % volatile matter content of Awe, Lafia, and Maiganga coals is 4.3, 21.7 and 12.7 whereas % fixed carbon of Awe, Lafia, and Maiganga 78.3,55.8 and 71.1 respectively. However, in terms of coal rank, the Awe is bituminous high volatile C, whereas Lafia and Maiganga coal are Subbituminous A, hence the reactivity and maturity of the coal decrease in the order of Awe (A) ˂ Lafia (L) ˂ Maiganga (M). The result shows that the coal samples are void of nitrogen and dangerous radioactive elements

Assessment of biogas production from mixtures of poultry waste and cow dung

The increase price of cooking gas and high rate of deforestation (firewood) has led to search for an alternative source for cooking. This study was carried out to produce biogas from cow dung and poultry waste as well as the respective co-digestion of cow dung and poultry dung as alternative fuel for cooking. Four-liters digester and gas collection system were designed and fabricated using locally available materials. The digesters were used to digest cow dung and poultry dung respectively as a single substrate as well as to digest cow dung and poultry dung respectively. The respective materials were collected locally. They were fermented, digested and analyzed in accordance with standard methods for the single substrate. The total volume of gas produced was recorded for different mixtures of cow and poultry waste. The total volume of gas produced ranged from 222 cm3 (20g cow dung plus 60g poultry waste) to 258cm3 (80g cow dung plus 0g poultry). The result shows that cow dung produces more gas than the poultry waste. Therefore, it is recommended that biogas factories or industries should be established that make use of the abundant animal waste. This will reduce the over-dependence on other forms of energy

Preservation of Axillary Lymph Nodes Compared with Complete Dissection in T1–2 Breast Cancer Patients Presenting One or Two Metastatic Sentinel Lymph Nodes: The SINODAR-ONE Multicenter Randomized Clinical Trial

Background: The SINODAR-ONE trial is a prospective noninferiority multicenter randomized study aimed at assessing the role of axillary lymph node dissection (ALND) in patients undergoing either breast-conserving surgery or mastectomy for T1–2 breast cancer (BC) and presenting one or two macrometastatic sentinel lymph nodes (SLNs). The endpoints were to evaluate whether SLN biopsy (SLNB) only was associated with worsening of the prognosis compared with ALND in terms of overall survival (OS) and relapse. Methods: Patients were randomly assigned (1:1 ratio) to either removal of ≥ 10 axillary level I/II non-SLNs followed by adjuvant therapy (standard arm) or no further axillary treatment (experimental arm). Results: The trial started in April 2015 and ceased in April 2020, involving 889 patients. Median follow-up was 34.0 months. There were eight deaths (ALND, 4; SNLB only, 4), with 5-year cumulative mortality of 5.8% and 2.1% in the standard and experimental arm, respectively (p = 0.984). There were 26 recurrences (ALND 11; SNLB only, 15), with 5-year cumulative incidence of recurrence of 6.9% and 3.3% in the standard and experimental arm, respectively (p = 0.444). Only one axillary lymph node recurrence was observed in each arm. The 5-year OS rates were 98.9% and 98.8%, in the ALND and SNLB-only arm, respectively (p = 0.936). Conclusions: The 3-year survival and relapse rates of T1–2 BC patients with one or two macrometastatic SLNs treated with SLNB only, and adjuvant therapy, were not inferior to those of patients treated with ALND. These results do not support the use of routine ALND

Sentinel lymph node biopsy versus axillary lymph node dissection in breast cancer patients undergoing mastectomy with one to two metastatic sentinel lymph nodes: sub-analysis of the SINODAR-ONE multicentre randomized clinical trial and reopening of enrolment

Background: The initial results of the SINODAR-ONE randomized clinical trial reported that patients with T1-2 breast cancer and one to two macrometastatic sentinel lymph nodes treated with breast-conserving surgery, sentinel lymph node biopsy only, and adjuvant therapy did not present worse 3-year survival, regional recurrence, or distant recurrence rates compared with those treated with axillary lymph node dissection. To extend the recommendation of axillary lymph node dissection omission even in patients treated with mastectomy, a sub-analysis of the SINODAR-ONE trial is presented here. Methods: Patients with T1-2 breast cancer and no more than two metastatic sentinel lymph nodes undergoing mastectomy were analysed. After sentinel lymph node biopsy, patients were randomly assigned to receive either axillary lymph node dissection followed by adjuvant treatment (standard arm) or adjuvant treatment alone (experimental arm). The primary endpoint was overall survival. The secondary endpoint was recurrence-free survival. Results: A total of 218 patients were treated with mastectomy; 111 were randomly assigned to the axillary lymph node dissection group and 107 to the sentinel lymph node biopsy-only group. At a median follow-up of 33.0 months, there were three deaths (two deaths in the axillary lymph node dissection group and one death in the sentinel lymph node biopsy-only group). There were five recurrences in each treatment arm. No axillary lymph node recurrence was observed. The 5-year overall survival rates were 97.8 and 98.7 per cent in the axillary lymph node dissection treatment arm and the sentinel lymph node biopsy-only treatment arm, respectively (P = 0.597). The 5-year recurrence-free survival rates were 95.7 and 94.1 per cent in the axillary lymph node dissection treatment arm and the sentinel lymph node biopsy treatment arm, respectively (P = 0.821). Conclusion: In patients with T1-2 breast cancer and one to two macrometastatic sentinel lymph nodes treated with mastectomy, the overall survival and recurrence-free survival rates of patients treated with sentinel lymph node biopsy only were not inferior to those treated with axillary lymph node dissection. To strengthen the conclusion of the trial, the enrolment of patients treated with mastectomy was reopened as a single-arm experimental study