Adjustment Methods for Planimetric Observations and Co-Ordinates in Survey Networks

Correction and adjustment of observed angles and sides in geodetic networks are necessary for the purpose of the correct location of coordinated points. Correction equations are usually in the form of linear overdetermined (observation) or underdetermined (condition) equations which are solved by the least squares theorem. The introduction of the electro-magnetic methods of linear measurement requires the adjustment of sides as well as the adjustment of angles necessary in classical triangulation nets. For the simultaneous adjustment of angles and sides two new sets of conditions have been introduced: (i) the area misfit condition, where the area obtained from distances and angles has to satisfy a special condition, and (ii) that the sum of the projections of the three sides of a triangle on the coordinate axes have to satisfy a zero condition. A special study has been made into the adjustment of the braced geodetic quadrilateral, as being one of the most favourable figures from the adjustment point of view. The different apices of this quadrilateral have been investigated to allow a choice to be made as to which of them shall be introduced in an angle misfit condition during adjustment. This gives rise to the conclusion that all apices will introduce the same corrections for all practical purposes. Since observed angles and sides are different physical quantities, the question of relative weighting has been given special attention and recommendations have been made in the light of various theoretical and practical investigations. The Systematic relaxation method for adjusting survey nets has been theoretically derived by Professors Southwell and Black based on the minimum strain-energy conserved in an elastic frame-work at the position of equilibrium. Using this theory mechanical analogues have been designed and constructed for the first time to carry out the adjustment of the triangulation net directly from field observations, without the necessity of forming and solving a set of linear equations. An analogue for the adjustment of angles was found to be excessively complicated mechanically and difficult to use in practice. Through the use of a direction adjustment method these limitations have been overcome. The final model constructed achieved comparable results to those obtained numerically by a least squares solution. Suggestions for a more highly developed version are made and the situations favourable to mechanical analogue computations are discussed. The use of an electrical analogue as suggested by Su using a D.C. circuit has been thoroughly investigated from both the theoretical and practical points of view, which showed that such a solution will be simple only for certain limited cases. As an alternative the possibilities of the more general purpose electronic analogue computer have been investigated via the solution of correction equations. Various examples have been solved on this computer which proved to have several advantages over other computation methods. Finally equivalent problems have been solved numerically on a digital computer for a comparison of the relative merits of analogue and digital methods for the particular case of adjustment of geodetic networks. The relative merits of these solutions are discussed in the light of different problems and circumstances

Exact implicit Solution of Nonlinear Heat Transfer in Rectangular Straight Fin Using Symmetry Reduction Methods

In this paper, the exact implicit solution of the second order nonlinear ordinary differential equation which governing heat transfer in rectangular fin is obtained using symmetry reduction methods. General relationship among the temperature at the fin tip, the temperature gradient at the fin base, the mode of heat transfer, and the fin parameters and ℰ is obtained. Some numerical examples are discussed and it is shown that the temperature of fin increases when approaching from the heat source. The relationship between the fin efficiency and the temperature of fin tip is obtained for any value of the mode of heat transfer . The relationship between the fin efficiency and both the parameter and ε the temperature gradient at the fin base is obtained. To our best knowledge, solutions obtained in this paper are new

Spectrophotometric studies on some nitrosonaphthols

1018-1021The UV and visible absorption spectra of some nitrosonaphthol derivatives have been studied in organic solvents of varying polarities. The dependence of the band shift on the nature of substituent, dielectric effect and specific solvation has been studied. The absorption spectra have also been studied in buffer solutions of varying pH values and the acid dissociation constants of the different ionisable groups have been determined using the half-height and the modified limiting absorbance methods. It is found that the nitroso substituent leads to a decrease in ionisation constants of the naphthalenic OH group

The role of losartan and enalapril in the protection against stress-induced gastric mucosal ulceration in rats

Background: Angiotensin II (ANG II) is a stress hormone and its level dramatically increases in the stomach during stress. In addition, it generates reactive oxygen species (ROS) with cellular damage and inflammation. So the aim of this study is to evaluate the mechanism of losartan and enalapril in the prevention of stress-induced gastric ulcer through their action on mucosal prostaglandin (PGs) and antioxidant enzymes and compare between them.Methods: Thirty- six adult male wistar albino rats weighing 180-200 g were divided into 6 groups; n= 6. Groups 1, 2, and 3 were received saline (normal control), losartan (3 mg/kg/day) and enalapril (10 mg/kg/day) i.p respectively for 4 weeks. Groups 4, 5, and 6 were pretreated with saline (ulcer control), losartan (3 mg/kg/day) and enalapril (10 mg/kg/day) i.p respectively for 4 weeks duration. On 29th day, group 4, 5 and 6 were submitted to gastric ulcer by water immersion method, then animals of all groups were sacrificed, stomachs were excised for gross and microscopic examination and determination of the mucosal levels of prostaglandin E2 (PGE2), superoxide dismutase (SOD), nitric oxide (NO) and catalase (CAT).Results: Stress produced gastric ulcer and a significant decrease in all measured gastric parameters compared to normal control group. Pre-treatment of rats with losartan or enalapril decreased the stress-induced alterations in mucosal parameters, but only losartan caused a significant increase in CAT activity in addition.Conclusions: Antagonize the action of ANG II by losartan and enalapril have preventive advantages in stress-induced gastric ulcer and losartan has better influence as it has an additional effect on CAT activity

Synthesis and efficiency of new pyridine, chromene and thiazole containing compounds as antimicrobial and antioxidant agents

ABSTRACT. The versatile scaffold, N'-(2-cyanoacetyl)-2-hydroxybenzohydrazide (3) was utilized in the production of new pyridine, chromene and thiazole derivatives as antimicrobial and antioxidant agents. The synthetic strategy involves the treatment of precursor 3 with various arylidene-malononitrile and 3-aryl-2-cyanoacrylate compounds to furnish substituted pyridines 5 and 7. The interaction of 3 with salicylaldehyde and/or phenyl isothiocyanate followed by cyclization with chloroacetone produced the corresponding 2-imino-2H-chromene-3-carbohydrazide and (thiazol-2-ylidene-acetyl)-salicylic acid hydrazide compounds 8 and 9, respectively. The structural features of the synthesized compounds were confirmed by using spectroscopic methods such as (IR, 1H NMR, 13C NMR and MS). The new pyridine, chromene and thiazole products showed potent antioxidants and antimicrobial activities. The thiazole derivative 9 exhibited the highest anti-bacterial and antifungal activities against S. aureus (75.0%) and B. subtilis (73.9%) and C. albicans (66.6%). The combination between salicylic acid hydrazide and thiazole moieties in the hybrid 9 indicated the best antioxidant activity (87.9%).                 KEY WORDS: Salicylic hydrazide, Arylidene-malononitrile, Pyridine, Thiazole, Antioxidant   Bull. Chem. Soc. Ethiop. 2022, 36(1), 137-148.                                                            DOI: https://dx.doi.org/10.4314/bcse.v36i1.12                                                      &nbsp

Simultaneous determination of paracetamol and tramadol in pharmaceutical tablets by derivative UV-Vis absorption spectrophotometry

A comparative study of the use of first derivative zero order crossing spectra for the resolution of Paracetamol and Tramadol hydrochloride in mixtures has been achieved showing the success of the first derivative method in resolving and quantifying both compounds. Using the first derivative, rather than the second derivative, results in improved signal to noise ratio. The absorption spectra of prepared mixtures were scanned in the range of 200-500 nm. The linear concentration ranges were 25-112 and 6-48 µg mL-1 for paracetamol and Tramadol hydrochloride, respectively. The method has been successfully used for prediction of concentrations of both compounds in mixtures with good selectivity, high sensitivity and extremely low relative error. Statistical comparison was performed using t-test at 95% confidence level. There was no significant statistical difference between the results obtained by the first derivative method and the accepted values for both compounds. Also, the percentage errors were very low which adds to the merits of our work in terms of both sensitivity and accuracy

Synthesis and Applications of a New Polysiloxane-Immobilized Macrocyclic Ligand System

Insoluble porous solid, macrocyclic 22-membered ring, 1-oxa-6,9,12,15,18-pentaaza-2,22-disilacyclododocosane polysiloxane ligand system has been prepared by the reaction of a macro-silane agent with tetraethylorthosilicate. The macro-silane agent was prepared by the reaction of imino-bis(N-2-aminoethylacetamide) ligand with 3-iodopropyltrimethoxysilane in 1:3 molar ratio. The new prepared polysiloxane system exhibits variable potentials for the extraction of metal ions (Fe3+, Co2+, Ni2+, Cu2+, Zn2+, Ag+, Cd2+, Hg2+, and Pb2+) from aqueous solutions. The ligand system shows high capacity to extract silver, lead, and mercury. Chemisorption of the metal ions by the ligand system at the optimum conditions was found in the order Ag + > Pb2+ > Hg2+ > Cu2+ > Ni2+ > Fe3+ > Co2+ > Cd2+ > Zn2+

Correction of anterior hypospadias without urethroplasty: glanular rotation procedure (the Hay technique)

Objectives: The aim was to present a simple technique for the correction of anterior hypospadiases without meatal advancement or urethroplasty.Background: Most of the techniques described for the correction of anterior hypospadias had the risk of complications: recession, flaying of the glans, fistula, and meatal stenosis that is not accepted when dealing with a trivial anomaly that is done only for cosmetic correction. A simple technique for correcting granular and some forms of coronal hypospadias without meatal advancement or urethroplasty is presented.Patients and methods: From June 2013 to June 2016, 183 patients presented for surgical repair of glanular or coronal hypospadias. The technique of glanular rotation procedure (GRP) was applied only for those cases that matched the criteria settled after degloving of the penis with an incision made 2mm proximal to the meatus touching the glans on both sides for 3–4 mm. Once the uppermost part of the meatus is at the same line with the upper end of the glans on both sides, the technique is applicable. The patients were followed in the OPD for 1 year after the repair for the evaluation of the results of the technique: the urinary stream, meatal size and position, presence of fistula, and the final cosmetic appearance.Results: Ninety-eight out of 183 (53.6%) boys had matched the criteria for application of the GRP technique. Their age ranged from 6 months to 3 years. All but three had an apical, slit-like meatus with good stream without stenosis and 2–3mm glans tissue encircling the ventral side of the meatus. Four cases had complications in the form of meatal stenosis in two cases, disruption of the glans in one case, and coronal fistula in one case. The overall complication rate was 4.1%.Conclusion: In properly selected cases, GRP is a simple efficient technique that has the advantage of reconstructing the glans over the urethra without the need of meatal advancement or urethroplasty.Keywords: coronal hypospadias, glanular hypospadias, without urethroplast