326 research outputs found
A novel proton transfer compound (a new molybdate salt) and its X-ray structure
A novel proton transfer compound (OHRNH3)22+(MoO4)2- (R = 2-methyl-1-propyl), derived from 2-amino-2-methyl-1-propanol and MoO2(acac)2, synthesized and characterized by 1H NMR, X-ray diffraction analysis, UV-Vis and FT-IR spectroscopy. The single crystal X-ray diffraction analysis revealed that intra- and intermolecular proton transfer from (MoO4H2) to (OHRNH2) results in the formation of a new molybdate salt that its fragments are connected through H-bonding and ion-pairing as shown in the X-ray crystal structure. This salt crystallizes in the space group P21/n P_1 of the monoclinic system, with four molecules per unit cell. The unit cell parameters are a = 13.6091(11) Å, b = 6.1049(5) Å, c = 17.0840(13) Å and β = 97.745(4)°. KEY WORDS: Proton transfer, Molybdate salt, X-ray structure, MoO2(acac)2, 2-Amino-2-methyl-1-propanol Bull. Chem. Soc. Ethiop. 2013, 27(1), 69-76.DOI: http://dx.doi.org/10.4314/bcse.v27i1.
An Experimental and Numerical Comparison of Flow Hydraulic Parameters in Circular Crested Weir Using Flow3D
Circular crested weirs consist of a circular crested of upstream and downstream walls. These weirs are widely used in hydraulic engineering as water discharge structures and can be used to control water level in channels and tanks. In the present study, using Flow3D software, hydraulic properties were investigated to find weir geometry optimization through CFD method. Also, this study attempted to investigate flow on some sections of circular crested weirs in 3 groups and 11 models. Upstream and downstream slope changes as well as the height of the weir were also studied. To validate the model, laboratory models were used. In the research, flow depth parameters on crest, pressure distribution, velocity distribution, energy loss on circular crested weirs, as well as the height and changes of upstream and downstream slope were evaluated. Flow depth on the body of circular crest in this state is about 0.71 (H1). Upstream slope changes on flow depth on the weir’s crest revealed that increasing upstream slope causes to the increase of flow relative depth (H1/R) on the crest about 62%. Downstream changes in H1/R values less than 0.7 have no significant effect on discharge coefficient; however, increasing H1/R values seems to cause more change in slope
Analysis of Opportunities and Challenges for R&D Management and the Role of the R&D Society for its Improvement – A Case Study in Iran
Research and Development (R&D) management in Iran is faced to many barriers and obstacles, in which R&D units are considered as the basic core of the product development and innovation. Due to structural shortcomings, a great number of organizations and industries have not been able to find their actual status. There are about different 1141 R&D units with a dispersion pattern in Iran. This paper considers and analyzes the R&D case study in one of the provinces located in the north part of Iran in order to enhance the potential R&D activities in respect with the industrialized areas and zones. In this province, there are about 2504 industrial units of which there are only 44 R&D units certified by the state government. However, there are limit numbers of these R&D units that are extensively active. This paper also addresses the current status in respect with the R&D activities to find out why there is a lack and depression of these activities in the industrial units. By considering the opportunity and challenges of these R&D units, there is a need to change these units to be active in order to quickly respond the market and demand requirements. Finally, a few alternative solutions and improvement plans are proposed, in which the Iranian R&D Society is responsible for supporting and succeeding these action plans towards the organization goals.R&D Management
A novel proton transfer compound (a new molybdate salt) and its X-ray structure
A novel proton transfer compound (OHRNH3)22+(MoO4)2- (R = 2-methyl-1-propyl), derived from 2-amino-2-methyl-1-propanol and MoO2(acac)2, synthesized and characterized by 1H NMR, X-ray diffraction analysis, UV-Vis and FT-IR spectroscopy. The single crystal X-ray diffraction analysis revealed that intra- and intermolecular proton transfer from (MoO4H2) to (OHRNH2) results in the formation of a new molybdate salt that its fragments are connected through H-bonding and ion-pairing as shown in the X-ray crystal structure. This salt crystallizes in the space group P21/n P_1 of the monoclinic system, with four molecules per unit cell. The unit cell parameters are a = 13.6091(11) Å, b = 6.1049(5) Å, c = 17.0840(13) Å and β = 97.745(4)°.DOI: http://dx.doi.org/10.4314/bcse.v27i1.
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Sustainable and inclusive demand-side resilience: a semi-dynamic model for outage costs
The power system is primarily designed and concerned with supplying electricity to its customers at all times. Nevertheless, power outages are inevitable; therefore, one of the challenges is to accurately determine the costs and damages to consumers in a fair and inclusive manner. Outage events are regularly costed based on a parameter called the Value of Lost Load (VoLL/VOLL). Although some of the influencing factors on outage costs have been identified in the literature, the exact determination of the damage to customers is still considered a big challenge. This work is an effort toward a more sustainable and inclusive demand-side resilience that provides a semi-dynamic model for the assignment of the power outage damage costs to the customers. The results of the proposed method show how using a semi-dynamic model for outage costs leads to more sustainable and inclusive operating decisions in the power system while also leads to a fairer allocation of costs
Prognostic significance of vascular endothelial growth factor expression in human ovarian carcinoma
The influence of vascular endothelial growth factor (VEGF) expression and microvessel density (MVD) on prognosis and the relationship between VEGF expression and MVD in ovarian carcinoma are not well defined. We studied VEGF expression in parallel with MVD by immunohistochemistry in 94 ovarian tumours (64 malignant, 13 borderline, and 17 benign) and correlated the results with the clinicopathologic prognostic factors of the disease to clarify their significance in this disease. Assessment of VEGF mRNA isoforms by RT-PCR was also performed. Of the malignant, borderline, and benign ovarian tumours respectively, two (3%), four (31%) and 16 (94%) were negative, 31 (48%), seven (54%) and one (6%) had low expressions, and 31 (48%), two (15%) and none (0%) had high expressions of VEGF. There were significant associations between the VEGF expression and disease stage (P = 0.002), histologic grade (P = 0.0004), and patient outcome (P = 0.0002). MVD did not correlate significantly with the clinicopathologic parameters. Likewise, no correlation was found between MVD and VEGF expression. The survival of patients with high VEGF expression was significantly worse than that of patients with low and negative VEGF expression (P = 0.0004). Multivariate analysis revealed that disease stage and VEGF expression were significant and independent prognostic indicators of overall survival time (P = 0.008 and P = 0.006 respectively). These findings suggest that in conjunction with the established clinicopathologic prognostic parameters of ovarian carcinoma, VEGF expression may enhance the predictability of patients at high risk for tumour progression who are potential candidates for further aggressive therapy. © 2000 Cancer Research Campaig
An investigation into the colloidal stability of graphene oxide nano-layers in alite paste
Recent studies have reported that graphene oxide (GO) is capable of enhancing the mechanical properties of hardened Portland cement (PC) pastes. The mechanisms proposed so far to explain this strengthening generally assume that GO is well dispersed in the pore solution of PC paste, serving as a reinforcing agent or nucleation-growth site during hydration. This paper investigates (i) the effect of GO on the hydration of alite, the main constituent of PC cement, using isothermal calorimetry and boundary nucleation-growth modelling, and (ii) the factors controlling the colloidal stability of GO in alite paste environment. Results indicate that GO accelerates the hydration of alite only marginally, and that GO is susceptible to aggregation in alite paste. This instability is due to (i) a pH-dependent interaction between GO and calcium cations in the pore solution of alite paste, and (ii) a significant reduction of GO functional groups at high pH
Analysis of Opportunities and Challenges for R&D Management and the Role of the R&D Society for its Improvement – A Case Study in Iran
Research and Development (R&D) management in Iran is faced to many barriers and obstacles, in which R&D units are considered as the basic core of the product development and innovation. Due to structural shortcomings, a great number of organizations and industries have not been able to find their actual status. There are about different 1141 R&D units with a dispersion pattern in Iran. This paper considers and analyzes the R&D case study in one of the provinces located in the north part of Iran in order to enhance the potential R&D activities in respect with the industrialized areas and zones. In this province, there are about 2504 industrial units of which there are only 44 R&D units certified by the state government. However, there are limit numbers of these R&D units that are extensively active. This paper also addresses the current status in respect with the R&D activities to find out why there is a lack and depression of these activities in the industrial units. By considering the opportunity and challenges of these R&D units, there is a need to change these units to be active in order to quickly respond the market and demand requirements. Finally, a few alternative solutions and improvement plans are proposed, in which the Iranian R&D Society is responsible for supporting and succeeding these action plans towards the organization goals
Analysis of Opportunities and Challenges for R&D Management and the Role of the R&D Society for its Improvement – A Case Study in Iran
Research and Development (R&D) management in Iran is faced to many barriers and obstacles, in which R&D units are considered as the basic core of the product development and innovation. Due to structural shortcomings, a great number of organizations and industries have not been able to find their actual status. There are about different 1141 R&D units with a dispersion pattern in Iran. This paper considers and analyzes the R&D case study in one of the provinces located in the north part of Iran in order to enhance the potential R&D activities in respect with the industrialized areas and zones. In this province, there are about 2504 industrial units of which there are only 44 R&D units certified by the state government. However, there are limit numbers of these R&D units that are extensively active. This paper also addresses the current status in respect with the R&D activities to find out why there is a lack and depression of these activities in the industrial units. By considering the opportunity and challenges of these R&D units, there is a need to change these units to be active in order to quickly respond the market and demand requirements. Finally, a few alternative solutions and improvement plans are proposed, in which the Iranian R&D Society is responsible for supporting and succeeding these action plans towards the organization goals
Oncocytic carcinoma of parotid gland: a case report with clinical, immunohistochemical and ultrastructural features
BACKGROUND: Oncocytic carcinoma is an extremely rare neoplasm of the salivary glands. We report a case of oncocytic carcinoma arising in a parotid gland in a 66-year-old female. METHOD: An excisional biopsy of the parotid tumor was performed. The specimen was submitted for histology and after fixation in formalin solution and inclusion in paraffin, 3–5 μm sections were stained with hematoxylin and eosin for conventional evaluation and Periodic acid Schiff stain. Immunohistochemical studies were performed using antibodies against mitochondrial antigen, keratin, S-100, alpha-actin, vimentin, alpha-1-antichymotrypsin as well as an ultrastructural analysis was performed. RESULTS: Frozen sections revealed an infiltrative growth pattern and the diagnosis of a malignant epithelial lesion was made. Permanent sections stained with haematoxylin and eosin revealed a neoplasm that had replaced a wide area of the parotid gland and had invaded subcutaneous adipose tissue. Perineural invasion was evident, but vascular invasion was not found. Neoplastic elements were large, round or polyhedral cells and were arranged in solid sheets, islands and cords. The cytoplasm was abundant, eosinophilic and finely granular. The nuclei were large and located centrally or peripherally. The nucleoli were distinct and large. Periodic acid Schiff stain demonstrated a granular cytoplasm. Immunohistochemistry demonstrated mithochondrial antigen, keratin, and chymotrypsin immunoreactivity in the neoplastic cells. Ultrastructural analysis revealed numerous mitochondria packed into the cytoplasm of the neoplastic cells. Thus, the final diagnosis was that of oncocytic carcinoma of parotid gland. CONCLUSION: This neoplasm shows clinical, microscopical, histological and ultrastructural features of oncocytic carcinoma and this must be considered in the differential diagnosis of other proliferations in the parotid gland with abundant granular cytoplasm and metastatic oncocytic carcinomas
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