Software-Based Speed Control of a DC Motor Using Pulse-Width Modulation

Speed control of DC Motor is vital in many applications. In this paper, an effort has been made to control the speed of the DC motor using pulse-width modulation (PWM) based on LabVIEW (Laboratory Virtual Instrument Engineering Workbench) program. LabVIEW provides a graphical programming environment suited for high-level or system-level design. Because of the global tendency towards using PC-based data acquisition and control systems in industrial applications, and the high accuracy, reliability, and flexibility requirements to the control system, LabVIEW software is used. Experimental results show that the proposed control scheme provides soft start/ stop transient operations, which improves the dynamic performance of the drive system, and keeps the speed constant regardless of the changes in supply voltage or load torque. Keywords: DC motor, Pulse-width modulation, Speed control, LabVIEW software, PC-based data acquisitio

A Novel Technique for Controlling CNC Systems

This paper describes a new CNC machine control unit MCU for numerically controlled NC systems used for machining or non-machining applications of numerical control NC. The proposed MCU is a combination of computer PC with Matlab software and Arduino microcontroller. The Matlab is used as an image processing program to accomplish the boarder detection of the image and convert it into digital output (0 and 1) for each pixel by a number of functions. The pixels will bias an array for the image, which will be processed to instructions. These instructions will be sent to Arduino microcontroller by the Matlab through Arduino cable (serial port). The Arduino microcontroller will generate the proper pulse trains to control the operation of stepper motors in the processing equipment (machine tool). The designed MCU has been implemented and experimentally tested in three-axes milling machine. Performance analysis of accomplished tasks verifies that the suggested approach for NC-part programming can be developed and used for different machining and non-machining applications of NC systems. Keywords: numerical control, NC-part programming, Matlab, Arduino microcontroller, milling machin

An Economic Study of the Most Important Variables Affecting Agricultural Investment in Egypt

Abstract The research aimed to study the most important variables affecting agricultural investment in Egypt and to achieve this the following sub-objectives are studied which are to study the most important factors affecting agricultural investment in Egypt during the period (2000-2020). As well as measuring the most important variables affecting agricultural investment in Egypt using the factorial analysis in Egypt during the period (2000-2020). The results of the factorial analysis showed that the degree of saturation on the first factor has strong relations with seven variables, which can be called the most important factors affecting agricultural investment in Egypt. The top of this factor was occupied by the variable of the technological level with the highest saturation of 0.979, followed by both the variable of total agricultural labor, the variable of the total value of agricultural income, the total value of agricultural exports, the total crop area, the total value of agricultural investment loans, the total value of agricultural imports with a degree of saturation amounting to about 0.968, 0.964, 0.958, 0.925, 0.806, 539 respectively. This is logical and in line with the current situation. The relationship between the total agricultural investment as a dependent variable (Y) and each of the interpretive independent variables that have an impact on agricultural investment in Egypt was estimated and the results of the model showed its statistical significance as well as the significance of the parameters of those independent variables. Their reference was consistent with economic logic

Effect of Gravel Size and Weir Height on Flow Properties of Gabions

لقد تم دراست العلاقة بين عمق الماء المتجمع امام السداد الحجرية والتصريف القادم من اعالي المجاري المائية في قناة مختبرية. حيث تم دراسة السطح الحر للماء في حالة التدفق الانتقالي وفي حالة الفيضان فوقه. تضمنت الدراسة تأثير ارتفاع جسم السداد الحجرية وخشونة المواد المستخدمه في الانشاء على عمق تدفق المنبع عن طريق اختبار أربعة ارتفاعات مختلفة من الهدارات وأربعة أحجام مختلفة من الحصى. أظهر تحليل النتائج المختبرية أن الانخفاض النسبي في عمق الماء المتجمع امام الهدارات يتراوح ما بين 38٪ و17٪ لنوع الجريان " التدفق خلال " عندما يزداد كل من خشونة المادة والتصريف، وفي نظام "التدفق الانتقالي"، تؤدي زيادة خشونة المواد والتصريف إلى انخفاض متوسط في عمق التدفق النسبي بين 7.6٪ و4.4٪ لارتفاع الهدارات الحجرية 15 سم و30 سم، على التوالي. يبدأ السداد الجرية في العمل كهدار يفيض الماء من فوقه عندما يكون متوسط عمق الماء إلى ارتفاع السداد (H / P) هو 1.19، في حين أن متوسط الزيادة الإجمالية في التصريف نسبة إلى تصريف السد الصلب هو 15 ٪. كما تم أقتراح علاقات تجريبية للتنبؤ بعمق الماء المتجمع أمام السداد الحجرية لكل من أنظمة التدفق الثلاثة. كما تم اقتراح علاقة تجريبية عديمة الابعاد للتنبؤ بمعامل التصريف لهذة السداد وبدقة جيدة.The variation between flow depth generated in front of gabion barrier and flow rate has been studied in open laboratory flume. Flow profiles have been observed for each of "Transition Flow" and "Overflow" regimes. Effects of gabion height and material coarseness on the upstream flow depth are studied by testing four different gabion heights and four different medium aggregate sizes. The analysis of experimental results showed that the relative decrease in flow depth varies between 38% and 17% for "Through Flow" type when material coarseness and discharge increase. In "Transition Flow" regime, increasing material coarseness and discharge causes an average decreases in relative flow depth of 7.6% and 4.4% for gabion heights 15cm and 30cm, respectively. Gabion begins to operate as an overflow weir when the average water depth to the gabion height (H/P) is 1.19. While the overall average increase in discharge relative to solid weir is 15%. Prediction relationships for flow depth upstream the gabion for each of the three flow regimes is suggested. Also, dimensionless relation to predict discharge coefficient are proposed with good accuracy

Properties of Flow through and over Gravel Basket Weir

يؤدي إنشاء هدارات من سلال الحصى في المجاري المائية إلى تراكم المياه أمام هذه المشأت المسامية، ويكون فيها منسوب المياه أقل من تلك التي تتجمع مقدمة الهدارات الصلبة. تتضمن هذه الدراسة، تقديرعمق الماء المتجمع امام هذه الهدارات مع قياس شكل السطح الحر للجريان والتنبؤ بقيمة معامل التصريف من خلال التجارب المختبرية. كما تمت دراسة أربعة أطوال مختلفة من الهدارات (15 ، 20 ، 25 و 30 سم) وأربع خشونات مختلفة من الحصى (1.13 ، 1.58 ، 2.19 و 2.27). وفقًا لذلك، فقد تم اختبارستة عشر نموذجاً في ظروف مختلفة من التدفق الحر. أظهرتحليل نتائج نظام الجريان "التدفق النافذ" أن الزيادة في عرض السد تسبب في زيادة عمق الماء المتجمع امام الهدارات ولجميع درجات الخشونة بنسبة 30٪ بينما تقلل الخشونة من العمق بنسبة 28٪. وفي "التدفق الانتقالي"، يؤدي مضاعفة الطول إلى زيادة عمق التدفق بنسبة 7٪، بينما تؤدي زيادة الخشونة من 1.13 إلى 2.72 سم في انخفاض عمق الجريان بنسبة 7٪. يبدأ نظام "التدفق الفائض" بالظهورعندما تساوي نسبة عمق الماء إلى عرض السد حوالي 0.75 للعرض الكبير و1.54 للعرض القليل. تشير المقارنة بين هدارات سلال الحصى والهدارات الصلبة إلى أن متوسط تقليل عمق الماء هو 7.5٪ للصلابة البالغة 1.13 سم و9٪  للصلابة البالغة 2.72 سم. تم اقتراح نماذج رياضية للتنبؤ بعمق المياه لأنظمة التدفق الثلاثة، أما بالنسبة لنظام "التدفق الفائض"، فقد اقتُرِحَت صيغة تجريبية لتقدير معامل التصريف بدقة مقبولة.Construction of gravel basket weir in waterways causes water accumulation in front of this porous structure less than solid weir. In the present study the upstream flow depth, water surface profile and discharge coefficient are investigated through laboratory experiments. Four different weir lengths (15, 20, 25 and 30 cm) and four different degrees of gravel coarseness (1.13, 1.58, 2.19 and 2.27) are studied. Accordingly, sixteen models are tested under different free flow conditions. Analysis of the results show that in "through flow" regime the increase in weir length raises the generated upstream depth for all coarseness degrees by 30% while coarseness lowers the depth by 28%. In "transition flow", however, doubling the length increases the flow depth by 7%, but increasing coarseness from 1.13 to 2.72 cm mean diameter causes 7% reduction in flow depth. The "overflow" regime begins to appear when the depth to length ratio equals 0.75 for long weir, and about 1.54 for shortest weir. A comparison between gravel basket weir and corresponding solid weir indicates that average depth reduction is 7.5% for coarseness of 1.13 cm and 9% for coarseness of 2.72 cm. Mathematical models for water depth prediction for the three flow regimes are presented. For "overflow" an empirical formula is proposed to estimate the coefficient of discharge with acceptable accuracy

An Economic Study of Dairy Production and Consumption in Egypt

The problem was the low volume of domestic production of milk and its products, despite the availability of large livestock producing milk, as a result of the low productivity of animals, which contributed to the lack of access per capita in Egypt to his sufficient share of milk. The research aimed to study the development of production, productivity of animal heads, the expected milk production of municipal cows, mixture, foreign and buffalo, actual dairy production, total expected production and expected increase of milk. The average amount of milk production of buffalo milk was estimated at about 2391 thousand tons, and the average productivity of buffalo is 697 kg / year, and the average amount of cattle milk production is about 3072 thousand tons. The average productivity of cows amounted to about 727 kg / year during the period. It was found that the average production of dairy head according to type and production areas during the period for municipal cows, mixture, foreign cows, buffaloes is about 516, 1121, 2765, 747 kg / year respectively. It was found that the average expected production of municipal cows reached about 2688 thousand tons during the same period. While the average expected production of mixed cows was 3215 thousand tons during the studied period. It turned out that the average total expected dairy production represented about 8457 thousand tons during the same period. The average expected per capita production was 88 kg/year, an increase of about 32.6% from the per capita available consumption

PEGylated liposomes : immunological responses

A commonly held view is that nanocarriers conjugated to polyethylene glycol (PEG) are non-immunogenic. However, many studies have reported that unexpected immune responses have occurred against PEG-conjugated nanocarriers. One unanticipated response is the rapid clearance of PEGylated nanocarriers upon repeat administration, called the accelerated blood clearance (ABC) phenomenon. ABC involves the production of antibodies toward nanocarrier components, including PEG, which reduces the safety and effectiveness of encapsulated therapeutic agents. Another immune response is the hypersensitivity or infusion reaction referred to as complement (C) activation-related pseudoallergy (CARPA). Such immunogenicity and adverse reactivities of PEGylated nanocarriers may be of potential concern for the clinical use of PEGylated therapeutics. Accordingly, screening of the immunogenicity and CARPA reactogenicity of nanocarrier-based therapeutics should be a prerequisite before they can proceed into clinical studies. This review presents PEGylated liposomes, immunogenicity of PEG, the ABC phenomenon, C activation and lipid-induced CARPA from a toxicological point of view, and also addresses the factors that influence these adverse interactions with the immune system

Exercise protects against obesity induced semen abnormalities via downregulating stem cell factor, upregulating Ghrelin and normalizing oxidative stress

Increased oxidative stress and hormonal imbalance have been hypothesized to underlie infertility in obese animals. However, recent evidence suggests that Ghrelin and Stem Cell Factor (SCF) play an important role in fertility, in lean individuals. Therefore, this study aimed at investigating whether changes in the levels of Ghrelin and SCF in rat testes underlie semen abnormal parameters observed in obese rats, and secondly, whether endurance exercise or Orlistat can protect against changes in Ghrelin, SCF, and/or semen parameters in diet induced obese rats. Obesity was modelled in male Wistar rats using High Fat Diet (HFD) 12-week protocol. Eight week-old rats (n=40) were divided into four groups, namely, Group I: fed with a standard diet (12 % of calories as fat); Group II: fed HFD (40 % of calories as fat); Group III: fed the HFD with a concomitant dose of Orlistat (200 mg/kg); and Group IV: fed the HFD and underwent 30 min daily swimming exercise. The model was validated by measuring the levels of testosterone, FSH, LH, estradiol, leptin, triglycerides, total, HDL, and LDL cholesterol, and final change in body weight. Levels were consistent with published obesity models (see Results). As predicted, the HFD group had a 76.8 % decrease in sperm count, 44.72 % decrease in sperm motility, as well as 47.09 % increase in abnormal sperm morphology. Unlike the control group, in the HFD group (i.e. obese rats) Ghrelin mRNA and protein were elevated, while SCF mRNA and protein were diminished in the testes. Furthermore, in the HFD group, SOD and GPx activities were significantly reduced, 48.5±5.8 % (P=0.0012) and 45.6±4.6 % (P=0.0019), respectively, while TBARS levels were significantly increased (112.7±8.9 %, P≤0.0001). Finally, endurance exercise training and Orlistat administration individually and differentially protected semen parameters in obese rats. The mechanism includes, but is not limited to, normalizing the levels of Ghrelin, SCF, SOD, GPx and TBARS. In rat testes, diet induced obesity down regulates SCF expression, upregulates Ghrelin expression, and deteriorate oxidative stress levels, which are collectively detrimental to semen parameters. Exercise, and to a lesse r extent Orlistat administration, protected effectively against this detrimental effect

Synthesis and reactions of 9,10-dihydro-9,10-ethanoanthracene-11,12-diacid hydrazides

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BM-MSCs alleviate diabetic nephropathy in male rats by regulating ER stress, oxidative stress, inflammation, and apoptotic pathways

Introduction: Diabetic nephropathy (DN), a chronic kidney disease, is a major cause of end-stage kidney disease worldwide. Mesenchymal stem cells (MSCs) have become a promising option to mitigate several diabetic complications.Methods: In this study, we evaluated the therapeutic potential of bone marrow-derived mesenchymal stem cells (BM-MSCs) in a rat model of STZ-induced DN. After the confirmation of diabetes, rats were treated with BM-MSCs and sacrificed at week 12 after treatment.Results: Our results showed that STZ-induced DN rats had extensive histopathological changes, significant upregulation in mRNA expression of renal apoptotic markers, ER stress markers, inflammatory markers, fibronectin, and intermediate filament proteins, and reduction of positive immunostaining of PCNA and elevated P53 in kidney tissue compared to the control group. BM-MSC therapy significantly improved renal histopathological changes, reduced renal apoptosis, ER stress, inflammation, and intermediate filament proteins, as well as increased positive immunostaining of PCNA and reduced P53 in renal tissue compared to the STZ-induced DN group.Conclusion: In conclusion, our study indicates that BM-MSCs may have therapeutic potential for the treatment of DN and provide important insights into their potential use as a novel therapeutic approach for DN