Critical analysis of portable web-tension measuring equipment

For satisfactory production or conversion of continuous material in web form it is generally important to control the tension in the web. The material may be plastics, paper or metal strip; conversion processes include web-fed printing or packaging machines and strip rolling mills. As speeds of production increase it is more likely that relatively high frequency tension perturbations may occur due to interaction between material properties and machine performance characteristics. This could result in frequent breakage of the web or unsatisfactory quality of the product. It is therefore of paramount importance to be able to measure and control tension variations accurately and with an adequate speed of response. The objectives of this investigation are to determine, by direct experiment and analytically, the limitations in static accuracy and dynamic performance of equipment for measurement of web tension. [Continues.

Experimental research into the effect of some operation factors and rock properties on the rate of penetration

Purpose. The purpose of this research is to investigate the effect of weight on bit (WOB), rotary speed (RPM), and some rock properties on the rate of penetration (ROP). Methods. Four types of rock were collected from different sites in the south of Egypt (Aswan sandstone, Isawya limestone, Assiut limestone, and Minya marble). These tested samples were drilled by diamond core bit using a fixed laboratory diamond drilling machine under conditions (400 and 1200 rpm), and loads from 12 to 220 kg. WOB, ROP, torque (T) and specific energy (SE) were continuously observed during the drilling trials. The effect of these factors on ROP were examined. Water is used as a flushing and cooling medium. Findings. The effect of some operation factors on the penetration rate regarding mineral composition and different rock type was evaluated and the general equation was carried out to predict the suitable operation factor which gives the best penetration Rate. Originality. The effect of some operation factors on the penetration rate regarding mineral composition and different rock type was evaluated and the general equation was carried out to predict the suitable operation factor which gives the best penetration Rate. Practical implications. The Results demonstrated that ROP was inversely proportional to compressive strength (CS), tensile strength (TS), and density. It was also found that Aswan sandstone, Isawya limestone, Assiut limestone, and Minya marble have CS 111.94 MPa, 131.22 MPa, 125.0 MPa, and 502.5 MPa respectively. Was established that ROP was directly proportional to porosity. Increasing ROP in case of Aswan sandstone is associated with increase in porosity – 23.158%, and in case of Assiut limestone and Isawya limestone ROP is also associated with an increase in porosity – 19.9% and 17.93% respectively. Decreasing ROP in case of Minya marble is associated with decrease in porosity – 2.314%. So, we concluded that marble has lower ROP due to its higher CS, TS, and density and lower porosity than other tested rocks.Мета. Вивчення впливу комплексу основних експлуатаційних параметрів і ряду фізико-механічних властивостей порід на швидкість буріння в умовах різних родовищ Південного Єгипту. Методика. Були відібрані 4 типи порід з різних районів на півдні Єгипту (Асуанської піщаник, вапняк Ісав, Ассіутскій вапняк і мармур Міньї). Експериментальні зразки отримано на стаціонарній лабораторній буровій установці з алмазним долотом при швидкостях обертання 400 і 1200 об/хв та при навантаженнях від 12 до 220 кг. Під час експериментів постійно вимірювалися навантаження на долото, частота обертання, крутний момент на долоті й питома енергія, а також досліджувався вплив цих факторів на швидкість буріння. Як розчин для промивання і охолоджуючий агент використовувалася вода. Результати. Встановлено залежності швидкості буріння від навантаження на долото, питомої енергії та частоти обертання і питомої енергії. Виявлено, що для всіх чотирьох типів породи швидкість буріння збільшується з ростом навантаження на долото, в той час як питома енергія зменшується з ростом швидкості буріння. Розроблено ефективний спосіб прогнозування продуктивності бурової установки. Встановлено, що швидкість буріння обернено пропорційна міцності на стиск, міцності на розтягнення й щільності, а також змінюється прямо пропорційно пористості. Визначено, що менша швидкість буріння мармуру пов’язана з великими значеннями міцності на стиск, розтяг і щільність, а також з меншою пористістю у порівнянні з іншими досліджуваними породами. Наукова новизна. Встановлено нові закономірності взаємозв’язку експлуатаційних параметрів буріння з урахуванням різного типу породи (пісковик, вапняк, мармур) та її мінерального складу, а також обґрунтовано головну умову експлуатаційного фактору, який забезпечує оптимальну швидкість буріння. Практична значимість. Отримані результати дозволяють вибирати оптимальні параметри і режими буріння в процесі розвідки умов залягання родовищ Південного Єгипту, їх мінерального вмісту та стратиграфічних особливостей. Результати будуть корисними для проектних організацій, наукових інститутів з геології й розвідки, а також гірничих підприємств.Цель. Изучение влияния комплекса основных эксплуатационных параметров и ряда физико-механических свойств пород на скорость бурения в условиях пород различных месторождений Южного Египта. Методика. Были отобраны 4 типа пород из различных районов на юге Египта (Асуанский песчаник, известняк Исавии, Ассиутский известняк и мрамор Миньи). Экспериментальные образцы получены на стационарной лабораторной буровой установке с алмазным долотом при скоростях вращения 400 и 1200 об/мин и при нагрузках от 12 до 220 кг. Во время экспериментов постоянно измерялись нагрузки на долото, частота вращения, крутящий момент на долоте и удельная энергия, а также и исследовалось влияние этих факторов на скорость бурения. В качестве промывочного раствора и охлаждающего агента использовалась вода. Результаты. Установлены зависимости скорости бурения от нагрузки на долото, удельной энергии и частоты вращения и удельной энергии. Выявлено, что для всех четырех типов породы скорость бурения увеличивается с ростом нагрузки на долото, в то время как удельная энергия уменьшается с ростом скорости бурения. Разработан эффективный способ прогнозирования производительности буровой установки. Установлено, что скорость бурения обратно пропорциональна прочности на сжатие, прочности на растяжение и плотности, а также изменяется прямо пропорционально пористости. Определено, что меньшая скорости бурения мрамора связана с большими значениями прочности на сжатие, растяжение и плотности, а также с меньшей пористостью по сравнению с другими исследуемыми породами. Научная новизна. Получены новые закономерности взаимосвязи эксплуатационных параметров бурения с учетом различного типа породы (песчаник, известняк, мрамор) и ее минерального состава, а также обосновано главное условие эксплуатационного фактора, который обеспечивает оптимальную скорость бурения. Практическая значимость. Полученные результаты позволяют выбирать оптимальные параметры и режимы бурения в процессе разведки условий залегания месторождений Южного Египта, их минерального содержание и стратиграфических особенностей. Результаты будут полезными для проектных организаций, научных институтов по геологии и разведке, а также горных предприятий.Our sincere gratitude for Mining and Metallurgical Engineering Dept. Faculty of Engineering, Assiut, Egypt for invaluable assistance to upgrade and guidance to completed this article

Vibration Control in MEMS Resonator Using Positive Position Feedback (PPF) Controller

In this paper, the vibration of a micro-electromechanical resonator with positive position feedback controller is studied. The analytical results are obtained to the first order approximation by using the multiple scale perturbation technique. The stability of the steady-state solution is presented and studied applying frequency response equations near the simultaneous primary and internal resonance cases. The effects of the controller and some system parameters on the vibrating system are studied numerically. The main result of this paper indicates that it is possible to reduce the vibration for the resonator system

Role of sequential semen samples in infertile men candidates for assisted reproduction: A prospective study

Objective: To study the beneficial effect of repeated sequential ejaculation in infertile men who are candidates for assisted reproduction.Materials and methods: The study included a total of 237 infertile males attending our infertility and IVF center from January 2016 till December 2017. All patients were asked to provide two semen samples (1–3 h apart) after an abstinence period of 3–7 days. The two consecutive semen samples were analyzed according to the 2010 WHO criteria for semen analysis and their parameters were compared.Results: The mean age for our study group was 35.7 years (20–56 year). Of the 237 subjects, 157 showed oligoasthenozoospermia on their initial semen sample while the remaining 80 were azoospermic. A statistically significant difference was detected between the 2 sequential semen samples regarding all semen parameters except grade A motility. Despite the significant decrease in seminal volume by sequential sampling, there was a statistically significant increase in sperm concentration in the second ejaculate compared to the first (6.2 ± 0.61 versus 3.4 ± 0.52 million/mL, respectively, p = 0.016). The mean normal sperm morphology also demonstrated a significant increase (2.1 ± 1.8–5.1 ± 2.6%, p < 0.002). Mean progressive sperm motility increased from 1.13 ± 0.31 to 1.7 ± 0.31% (p = 0.010) on repeated sampling. Also, we were able to retrieve viable sperm in 15% of the azoospermic patients whom were known to be azoospermic on previous occasions.Conclusions: Obtaining consecutive semen samples leads to improvements in the quality of many semen parameters (sperm concentration, motility and morphology) which may be of special importance for management of infertile couples especially those attempting assisted reproductive techniques

EVALUATION OF GROUNDWATER QUALITY OF SIWA OASIS

In discussing the water quality evaluation for use in different purposes, the author will briefly examine some of the major important water quality standards. These standards serve as a basis for appraisal of the results of chemical water analysis in terms of suitability of the water for various intended uses. According to total dissolved salts (TDS),  major  ions as cations ( Ca2+, Mg2+, Na+, K+), anions (CO₃2â», HCO₃â»Â  ,SOâ‚„2â», Clâ»), with some heavy metals such as Al3+, B3+ , Cd2+, Co2+, Cr3+, Cu2+, Fe3+, Mn2+,  Mo2+, Ni2+,  Pb2+, Sr2+, V2+   and Zn2+  The results  indicate  that  the samples of Nubian sandstone aquifer is suitable for drinking of human and livestock , suitable for laundry purposes and for irrigation. While the samples of Fractured dolomite limestone aquifer are unsuitable for drinking and irrigation.Â

Removal of Lignin from Pulp Waste Water's Black Liquor via By-Pass Cement Dust

The potential use of inexpensive and available by-pass cement dust as an inorganic sorbent for the removal of organic matter (lignin) from black liquor of pulp wastewater by adsorption methodology was investigated using the batch technique. The cement dust is found to remove lignin efficiently from black liquor (the untreated cement dust (70.47%), the thermally treated one at 1000 °C (78.63%), and chemically treated dust (80.62%). The factors affecting the uptake percentage such as time, dose, pH and temperature were investigated to assess the optimum conditions for lignin removal. X-ray patterns were studied to reveal the relationship between the main constituents of each cement dust phase (untreated, thermally and chemically treated) and lignin uptake. By applying Langmuir and Frendlich adsorption isotherms it was found that the adsorption process of lignin from black liquor on by-pass cement dust achieves Frendlich model, which suggests that adsorption is not restricted to one specific layer of sites but involves multi-layers. Also, stripping of lignin by using different strippers (organic, mineral acids, bases and salts) was investigated. The results obtained show that the organic strippers give high stripping percentage for cyclohexane (90.10%) because lignin is a non-polar compound that dissolves in non-polar solvents. In the case of acids, bases and salts the best results were obtained with much diluted solutions (0.001 mol/L). Stripping of lignin from by-pass cement dust is considered as a way of its recycling for different applications

Functional modelling of a novel mutation in BBS5.

BACKGROUND: Bardet-Biedl syndrome (BBS) is an autosomal recessive ciliopathy disorder with 18 known causative genes (BBS1-18). The primary clinical features are renal abnormalities, rod-cone dystrophy, post-axial polydactyly, learning difficulties, obesity and male hypogonadism. RESULTS: We describe the clinical phenotype in three Saudi siblings in whom we have identified a novel mutation in exon 12 of BBS5 (c.966dupT; p.Ala323CysfsX57). This single nucleotide duplication creates a frame shift results in a predicted elongated peptide. Translation blocking Morpholino oligonucleotides were used to create zebrafish bbs5 morphants. Morphants displayed retinal layering defects, abnormal cardiac looping and dilated, cystic pronephric ducts with reduced cilia expression. Morphants also displayed significantly reduced dextran clearance via the pronephros compared to wildtype embryos, suggesting reduced renal function in morphants. The eye, kidney and heart defects reported in morphant zebrafish resemble the human phenotype of BBS5 mutations. The pathogenicity of the novel BBS5 mutation was determined. Mutant mRNA was unable to rescue pleiotropic phenotypes of bbs5 morphant zebrafish and in cell culture we demonstrate a mislocalisation of mutant BBS5 protein which fails to localise discretely with the basal body. CONCLUSIONS: We conclude that this novel BBS5 mutation has a deleterious function that accounts for the multisystem ciliopathy phenotype seen in affected human patients

The Relationship of Sperm Motility Pattern and Its Ability to Agglutinate with Vaginal Sperm Selection, Uptake in Sperm Storage Tubules and Competitiveness

To ensure survival, some unique features can be distinguished in birds that help them maintain reproduction. These features include the ability to store sperm for long periods within the utero-vaginal junction, a high sperm concentration per ejaculate, and polyspermy fertilization. Sperm face many challenges prior to fertilization. After copulation, most ejaculated sperm exit the female reproductive tract, and less than 1% continue in an attempt to achieve fertilization. In addition, egg size is substantially larger than sperm size because of the presence of the egg yolk. This results in a large number of sperm penetrating the egg away from the oocyte. These challenges have triggered evolutionary changes to maintain the existence of many species, such as the enormous relative size of the testis, which produces billions of sperm each day, and the ability to store viable sperm for long periods in the oviduct to ensure asynchronous fertilization. This chapter discusses several contemporary and sometimes controversial points regarding sperm behavior and their storage in the oviduct