Experimental Characterization of Electrical Discharge Machining of Aluminum 6061 T6 Alloy using Different Dielectrics

Electrical discharge machining is a non-traditional machining method broadly employed in industries for machining of parts that have typical profiles and require great accuracy. This paper investigates the effects of electrical parameters: pulse-on-time and current on three performance measures (material removal rate, microstructures and electrode wear rate), using distilled water and kerosene as dielectrics. A comparison between dielectrics for the machining of aluminum 6061 T6 alloy material in terms of performance measures was performed. Aluminum 6061 T6 alloy material was selected, because of its growing use in the automotive and aerospace industrial sectors. The experimental sequence was designed using Taguchi technique of L9 orthogonal array by changing three levels of pulse-on-time and current, and test runs were performed separately for each dielectric. The results obtained show that greater electrode wear rate (EWR) and higher material removal rate (MRR) were achieved with distilled water when compared with kerosene. These greater EWR and MRR responses can be attributed to the early breakage of the weak oxide and carbide layers formed on the tool and alloy material surfaces, respectively. The innovative contributions of this study include, but are not limited to, the possibility of machining of aluminum 6061 T6 alloy with graphite electrode to enhance machinability and fast cutting rate employing two different dielectrics.Peer reviewe

The Efficiency of Barley ( Hordeum vulgare

The current study focused on testing the hypolipidemic activity of two doses of barley bran on hypercholesterolemic male rats. Twenty-four male albino rats weighing 180–200 gm were divided into four groups. The first group (G1) was the negative control, the second group (G2) was the positive control group fed 2% cholesterol in the diet, and rats of the third and the fourth groups were fed 2% cholesterol and were cosupplemented with 5% and 10% barley bran, respectively, for 8 weeks. The hypercholesterolemic rats of (G2) showed an increase in lipid profile, liver enzymes, lactate dehydrogenase, creatine kinase-MB, and lipid peroxide and a decrease in antioxidant enzymes, whereas kidney function, fasting blood sugar, glycated hemoglobin total protein, and total bilirubin were not significantly affected compared with the negative control group in G1. Moreover, histology of heart, liver, and kidney of G2 rats showed histopathological changes compared with the negative control. Administration of the two doses of barley bran in G3 and G4 to the hypercholesterolemic rats ameliorated the level of lipids, liver enzymes, lactate dehydrogenase, and creatine kinase-MB. In addition, the histology of heart, liver, and kidney tissues nearly restored the normal state as in G1

Correlation between Biofilm Formation, Multi-Drug Resistance and AlgD Gene among Pseudomonas aeruginosa Clinical Isolates

الخلفية: الزوائف الزنجارية هي عبارة عن بكتريا انتهازية مسببة للامراض التي ترتبط بالإصابة بالعدوى المستمرة التي يصعب استئصالها.الهدف: تهدف هذه الدراسة إلى تحديد قدرة تكوين الغشاء الحيوي في الزوائف الزنجارية وارتباطه بمقاومة المضادات الحيوية وعلاقتها بوجود جين ال  AlgD.المرضى وطريقة العمل: أجريت الدراسة الحالية في مستشفى أزادي التعليمي العام في مدينة كركوك خلال الفترة من أغسطس 2017 حتى مايو 2018 ، تم الحصول على 100 عزلة من الزائفة الزنجارية من 1260 عينة سريرية مختلفة. تم تحديد الحساسية للمضادات الحيوية بواسطة طريقة كيربي باور، تم تحليل تكوين الغشاء الحيوي بطريقة الميكروتايتر بليت ، جين AlgD تم الكشف عنه بواسطة تفاعل البلمرة المتسلسل.النتائج: اقل مقاومة للمضادات الحيوية وجد ضد: ببراسلين/ تازوباكتام (5%) , سيفيبيم (24%), سيفتازيديم (26%), بينما كانت النسبة الاكبر مقاومة ضد: الاموكسيسيلين/ حامض الكلافيولانك (98%) و ترايميثوبريم/ سلفامثوكزازول (97%).وكانت (60%) من هذه العزلات مقاومة للعديد من الأدوية. وجد أن (98%) من العزلات كانت لها قابلية تكوين الغشاء الحيوي. تم الكشف عن وجود جين AlgDبواسطة تفاعل البلمرة المتسلسل حيث وجد أن  (98%) من العزلات حاملة للجين, مع جود هذا الجين AlgD في العزلات المكونة للغشاء الحيوي فقط. الاستنتاجات: كان الإرتباط معنويا بين قابلية تكوين الغشاء الحيوي ومقاومة المضادات الحيوية, ووجد ان هنالك علاقة قوية بين وجود AlgD جين و تكوين الغشاء الحيويBackground: Pseudomonas aeruginosa is an opportunistic pathogenic bacterium that associated with persistent infections that are difficult to eradicate. Objective: This study aims to determine biofilm forming potential of P. aeruginosa and its correlation with antibiotics resistance and presence of AlgD gene. Materilals and Methods: The present study carried out in Azady teaching general hospital in Kirkuk city during the period from August 2017 to May 2018, one hundred isolates of Pseudomonas aeruginosa had been obtained from (1260) different clinical specimens. Antibiotic susceptibility was determined by Kirby-Bauer method, biofilm formation analyzed by Microtiter plate quantitative method, and AlgD gene was determined by polymerase chain reaction (PCR).Results: A lower percentage of antibiotic resistance was against piperacillin/tazobactam (5%), cefepime (24%), and ceftazidime (26%) while, higher resistance percentage was seen against amoxicillin/clavulanic acid (98%) and trimethoprim/sulfamethoxazole (97%), multi-drug resistance (MDR) formed (60%) of total isolates. Biofilm formation found in (98%) of total isolates. AlgD gene detected by PCR technique found in (98%) of total isolates, AlgD gene was found only in biofilm former isolates. Conclusions: Significant correlation found between biofilm formation and antibiotic resistance. Strong correlation observed between presence of AlgD gene and biofilm formation

Effect of pregnancy on packed cell volume and total white blood cells count among Sudanese pregnant women attending antenatal care at Ribat University Hospital (Khartoum state)

Background: During pregnancy the women undergo several structural and physiological changes almost in all body systems including the hematological profile. The main reported hematological change is the plasma expansion and haemodilution which affect the red blood cells(RBCs) and white blood cells (WBCs) count in addition to other hematological indices including packed cell volume (PCV). The objective of this study was to assess the effect of pregnancy on packed cell volume and white blood cells among Sudanese pregnant women and derive a formula for the normal values in pregnant women in relation to the packed cell volume.Methods: An analytical case control study was conducted in Khartoum state, Sudan 2017. The study included20 Sudanese pregnant women in the second and third trimesters attending the antenatal care at The National Ribat university hospital and 20 Sudanese non-pregnant women in the same age group as control. A questionnaire was used to collect socio-demographic and clinical data.5ml of venous blood was collected in a container containing EDTA. Complete blood count (CBC) was measured by using automated cell counter Sysmex.Results: There was statistically significant decrease in PCV value during 2nd and 3rd trimesters of pregnancy compared to the non-pregnant control group with p values (0.00 and 0.04 respectively), and statistically significant increase in WBCs count during 2nd and 3rd trimesters of pregnancy compared to the non-pregnant control group with p values (0.04 and 0.00 respectively). Also, a progressive increase in WBCs count with gestational age was demonstrated (second trimester 6.65×103/uL, third trimester 7.43×103/uL). The results showed mean WBCs of 7.79×103/uL, when compared to the estimated values the results showed no significant difference with the mean WBCs in 2ndand 3rdtrimesters (p value 0.06 and 0.39 respectively).Conclusions: During pregnancy there was statistically significant decrease in PCV values, statistically significant increase in WBCs count and by considering the haemodilution factor there was a higher increase in WBCs count

Prevalence of Metallo-β-Lactamase producing Pseudomonas aeruginosa in wound infections in Duhok city, Iraq

Background: Pseudomonas aeruginosa is common pathogen causing nosocomial infection. Acquired drug resistance and Metallo-β-lactamases (MBL) production have recently emerged as one of the most worrisome resistance mechanism that hydrolyze all beta-lactam antibiotics including penicillins, cephalosporins and carbapenems, with the exception of aztreonam. The aim was to find out the prevalence of multi drug resistant (MDR) and Metallo-β-lactamase (MBL) positive isolates of P. aeruginosa in wounds samples which are a serious concern.Methods: Pseudomonas aeruginosa strains were obtained by standard isolation and identification techniques from 307 wound samples of hospital. Strains were then subjected to susceptibility testing for anti-pseudomonas drugs as per Clinical and Laboratory Standards Institute (CLSI) guidelines. Carbapenems resistant strains were selected for the detection of MBL enzyme production by disc potentiation test. Production of MBL was confirmed by enhancement of inhibition zone around imipenem and meropenem discs impregnated with EDTA, as compared to discs without EDTA.Results: Amongst the 71 isolates of P. aeruginosa, 62(87.3%) isolate were imipenem-sensitive, while 9(12.7%) isolates were found to be imipenem resistant and MBL producers. Very high resistance to antibiotics was recorded amongst MBL producers’ P. aeruginosa compared with non-MBL imipenem-sensitive strains.Conclusion: Study indicates that, surveillance for the detection of MBL is necessary. The rapid dissemination of MBL producers is worrisome and necessitates the implementation of proper and judicious selection of antibiotics especially carbapenem.

Wave Energy in Clatsop County, OR: An Economic Impact Analysis

This study analyzes the economic impacts of building a wave energy commercial generation project in Clatsop County, Oregon. The modeled project is relatively small, and was produced by reviewing relevant wave energy literature and working with two local wave energy developers to estimate the expenditures and related costs of the project. We find that the construction and ongoing operation of a commercial wave energy project would create gains in employment, income, and output in the area as well as preparing Astoria for further wave energy development

Design of an Intelligent Traffic Light Control System

Today, the number of cars is rapidly increasing which creates a real traffic control problem. While the conventional traffic control systems are inconvenient to provide fast and fair solutions for the congestion problem. This research addresses the traffic control problem and hence proposes an intelligent traffic light control system. In particular, the proposed system senses the presence or absence of cars on each lane, and then estimates the time to open each lane, which is proportional to the number of cars on that lane. Practically, the system circuit has been printed on a board with three main components; namely pressure sensors, microcontroller, and traffic lights. Then a C program has been developed to enable the microcontroller for receiving inputs from sensors, calculating the times to open lanes and sending appropriate logic decisions to traffic light. The obtained results prove the accuracy and reliability of the system.    In addition to the practical test, the intelligent traffic light control system has been successfully simulated, where the simulation results are found to be the same as the calculated ones

Design and Development of a Photovoltaic Water Pumping

The theory of design and analysis of experiments has been primarily developed by statisticians engaged mostly in agricultural research. The theory has now found applications in other fields of research, because it is based on general principles concerning the statistical behavior of observations which arise either freely in nature or in artificial laboratory conditions (Badrldin and Kshirsagar,1990). Incomplete block designs were developed to suit experiments where the number of experimental units per block is less than the number of treatments. The concept of incomplete block designs augmented by a control was first introduced by Das (1954). He considered  the case where (q ³ 1) new treatments are introduced into the design and all included in each block. He concluded that  q should be chosen as low as possible to keep the block size to a reasonable level. Pearce (1960) considered the case where a Balanced Incomplete Block (B. I. B.) design is supplemented by a control, where the test treatments are replicated r times except the control which is  replicated r0 times, while all pairs of treatments occurs l times in blocks, the supplemented treatment occurs l0 times with any other treatment(Ture,1982). Pesek (1974) considered the case of a B. I. B. design having an extra control in each block. He utilized Rao’s general formulas to obtain the variances of the elementary treatment contrast between any pair of test treatment and any treatment and the control. He also obtained the efficiency factor of this design and showed that this design is more efficient than a B. I. B. design for comparing treatments with a control, but is less efficient for pair wise comparisons between the test treatments. Many times, for important new drugs and for serious diseases, investigations are carried out simultaneously at various locations under different climatic conditions, for a series of treatments. In such cases, the result of all such investigations need to be combined to produce an overall estimate of the effect of treatment contrast to the control. In this study the case where a control is added to each block in a B. I. B. design is considered. The variances of the elementary treatment contrast between any pair of test treatments and any treatment and the control were obtained. The general theory of inter & intra -block estimates of treatment effect when a B. I. B. design is augmented by a control was investigated, the general theory of a balanced incomplete block design is given where a control is added to each block. The estimation of weight for combining inter and intra-block estimates is also dealt with, and the weight for combining inter-block estimates of treatment contrast was also considered. The object of this study is to get a minimum variance of the treatment contrast between the inter and intra block estimates when a control treatment is added to each block in B. I. B. design

Structural Dependence of the In Vitro Cytotoxicity, Oxidative Stress and Uptake Mechanisms of Poly(propylene imine) Dendritic Nanoparticles

The in vitro cytotoxic and intracellular oxidative stress responses to exposure to poly (propylene imine) (PPI) dendritic nanoparticles of increasing generation (number of repeated branching cycles) (G0-G4) were assessed in an immortal non-cancerous human keratinocyte cell-line (HaCaT). Confocal fluorescence microscopy with organelle staining was used to explore the uptake and intracellular trafficking mechanisms. A generation and dose dependent cytotoxic response was observed, increasing according to generation and therefore number of surface amino groups. A comparison of the cytotoxic response of G4 PPI and the related G4 Poly (amido amine) dendrimer indicates that the PPI with the same number of surface amino groups elicits a significantly higher cytotoxic response. The trend of cytotoxicity versus dendrimer generation and therefore size is discontinuous in the region of G2, however, indicating a difference in uptake mechanism for higher compared to lower generations. Whereas the higher generations elicit an oxidative stress response at short exposure times, the lower generations indicate and antioxidant response. Confocal microscopy indicates that, whereas they are prominent at early exposure times for the larger PPI dendrimers, no evidence of early stage endosomes was observed for lower generations of PPI. The results are consistent with an alternative uptake mechanism of physical diffusion across the semi-permeable cell membrane for the lower generation dendrimers and are discussed in terms of their implications for predictive models for nanotoxicology and design strategies for nanomedical applications