3,567 research outputs found
High-Rate Space-Time Coded Large MIMO Systems: Low-Complexity Detection and Channel Estimation
In this paper, we present a low-complexity algorithm for detection in
high-rate, non-orthogonal space-time block coded (STBC) large-MIMO systems that
achieve high spectral efficiencies of the order of tens of bps/Hz. We also
present a training-based iterative detection/channel estimation scheme for such
large STBC MIMO systems. Our simulation results show that excellent bit error
rate and nearness-to-capacity performance are achieved by the proposed
multistage likelihood ascent search (M-LAS) detector in conjunction with the
proposed iterative detection/channel estimation scheme at low complexities. The
fact that we could show such good results for large STBCs like 16x16 and 32x32
STBCs from Cyclic Division Algebras (CDA) operating at spectral efficiencies in
excess of 20 bps/Hz (even after accounting for the overheads meant for pilot
based training for channel estimation and turbo coding) establishes the
effectiveness of the proposed detector and channel estimator. We decode perfect
codes of large dimensions using the proposed detector. With the feasibility of
such a low-complexity detection/channel estimation scheme, large-MIMO systems
with tens of antennas operating at several tens of bps/Hz spectral efficiencies
can become practical, enabling interesting high data rate wireless
applications.Comment: v3: Performance/complexity comparison of the proposed scheme with
other large-MIMO architectures/detectors has been added (Sec. IV-D). The
paper has been accepted for publication in IEEE Journal of Selected Topics in
Signal Processing (JSTSP): Spl. Iss. on Managing Complexity in Multiuser MIMO
Systems. v2: Section V on Channel Estimation is update
Study the effect of the adding of Ash of Palm Fronds on the Mechanical Properties for High Density Polyethylene (HDPE).
The mechanical properties of (HDPE - ash of palm fronds) composites were studied. The range of added powder of ash of palm fronds has the values (0%, 1%, 2%, 3%, 4%, 5%, 7.5% and 10%) of polyethylene weight and the best ratio was (10 %). The mechanical properties of (HDPE / ash of palm fronds) composites were analyzed as a function of the added powder amount. All prepared composites showed improved powder dispersion in the high density polyethylene matrix. More composites displayed lower elongation of break compared to pure HDPE. The results lead to that the strength at breaks will be affected little till the percentage (3%) is (6.8 Mpa), and increased after that with increasing the percentages, also indicate a lowered in young's modules (Young modulus) which at the percentage (3%). The highest value of the proportional limit was when the proportion of the added polymer (2%) is (431.2 N) while the less proportion limit of which (372 N) at the percentage is (4%). Keywords: polymer, Mechanical properties, Ash of palm fronds; Polymer composites; high density polyethylene, Fillers
The nutritional, hormonal and vitamin status in overweight and obesity
Background: Obesity is a global epidemic which is increasing dramatically in overwhelming rates among males and females of all age categories in developing and developed countries.Methods: The first phase of the project involves the questionnaires which apply to all the Participants in research. We also use the lab investigation to determine the abnormality in overweight and obese people. Then we will analysis and combine the results to others research and give output and recommendation that we hope helping us to limiting of increase incidence of obesity.Results: sample show that high cholesterol above normal average approximately in 31.05% of the participants while the triglyceride rate increased in 31.67%. A lack of vitamin D, as the rate did not exceed 18±6.8, in individuals with the BMI 25-29, and to be 13±8.82, in individuals with the BMI>30. Vitamin B12 rate became borderline in individuals with BMI 25-29, and deficient in individuals with BMI>30.Conclusions: Obese Saudi individuals have several nutritional deficiencies specifically in vitamins D and B12 despite their overweight. Efforts should be focused to increase awareness of healthy and weight control
A Green Synthesis of Iron/Copper Nanoparticles as a Catalytic of Fenton-like Reactions for Removal of Orange G Dye
تدرس هذه الورقة البحثية استخدام طريقة صديقة للبيئة وغير مكلفة لإزالة الصبغة البرتقالية G (OG) من المحلول المائي، حيث تم استخدام مستخلص أوراق شجرة الفيكس لغرض التخليق الأخضر لجسيمات الحديد/نحاس ثنائية الفلز النانوية (G-Fe/Cu-NPs). بعد أن تم تحضير G-Fe/Cu-NPs تم تشخيصها باستخدام مجهر الماسح الالكتروني، BET، مجهر القوة الذرية، مطياف الطاقة المشتتة، مطيافية الأشعة تحت الحمراء، و مقياس زيتا. أظهرت نتائج التشخيص بأن شكل G-Fe/Cu-NPs كان مستدير شبه كروي ويتراوح الحجم بين 32-59 نانومتر بينما كانت مساحتها السطحية 4.452 م2/غم. فيما بعد اُستخدمت الجسيمات النانوية الناتجة كعامل مساعد في تفاعلات الأكسدة الشبيهة بالفنتون. حيث أن كفاءة تحلل صبغة OG اعتمدت بشكل كبير على تركيز الهيدروجين بيروكسايد (1.7-5.28 ملي مولاري)، كمية العامل المساعد (0.4-1.6 غم/لتر)، درجة الحامضية (2-7)، تركيز OG الابتدائي (25-75 ملغم/لتر) ودرجة الحرارة (20-50 درجة مئوية). أظهرت التجارب الدفعية أن 94.8% لتركيز 50 ملغم/لتر من صبغة OG تمت ازالته عند الظروف المثلى للهيديروجين بيروكسايد، كمية العامل المساعد، درجة الحامضية، ودرجة الحرارة والتي كانت 3.52 ملي مولاري،1غم/لتر، 3، و 40 درجة مئوية على التوالي خلال زمن مقداره 30 دقيقة. أيضاً أظهرت نتائج دراسة النماذج الحركية بأن ازالة صبغة OG تتبع نموذج حركي من الدرجة الثانية. أخيراً، تم دراسة الديناميكية الحرارية للتفاعل وخلُصت إلى ان التفاعل ماصاً للحرارة وله طاقة تنشيط مقدارها 29.725 كيلوجول/مول.This research paper studies the use of an environmentally and not expensive method to degrade Orange G dye (OG) from the aqueous solution, where the extract of ficus leaves has been used to fabricate the green bimetallic iron/copper nanoparticles (G-Fe/Cu-NPs). The fabricated G‑Fe/Cu-NPs were characterized utilizing scanning electron microscopy, BET, atomic force microscopy, energy dispersive spectroscopy, Fourier-transform infrared spectroscopy and zeta potential. The rounded and shaped as like spherical nanoparticles were found for G-Fe/Cu‑NPs with the size ranged 32-59 nm and the surface area was 4.452 m2/g. Then the resultant nanoparticles were utilized as a Fenton-like oxidation catalyst. The degradation efficiency of OG dye highly depends on H2O2 concentration (1.7-5.28 mM), catalyst dose (0.4-1.6 g/L), pH (2-7), initial OG concentration (25-75 mg/L), and temperature (20-50 ℃). Batch experiments showed that 94.8 % of 50 mg/L of OG dye was removed within the optimum peroxide concentration, dose, pH and temperature which were 3.52 mM, 1 g/L, 3, and 40℃ respectively along with 30 min contact time. The results of kinetic models showed that OG removal followed the second-order model. Finally, the thermodynamic study of reaction was also examined and concluded to endothermic reaction with 29.725 kJ/mol activation energy
Evolution of second trimester low implanted placenta to previa at term: a prospective cohort study
Background: The objective of this study is to identify the percentage of low implanted placenta (LIP) at second trimester of pregnancy and identify the risk factors of its persistence to placenta previa (PP) at term.Methods: Through a registered prospective cohort study conducted at tertiary hospital in Upper Egypt, authors screened all pregnant ladies comes to present facility for antenatal second trimester USG between 18-24 weeks gestation. All participants interviewed for detailed risk factors of placenta previa. Those diagnosed to have a LIP (≤1.5 cm from the internal os) had had TVS to confirm the exact distance between the lower edge of the placenta and the internal os. Serial USG had been done every 4 weeks up to delivery to measure the same distance. The primary outcome was the percentage of LIP at 18-24 weeks. Logistic regression analysis was performed to predict the risk factors for PP at term.Results: Through screening of 1000 pregnant lady, LIP had been identified in (52 cases) 5.2% of pregnant women between 18-24 weeks. This percentage dropped gradually to reach 1.3% at 36 weeks of gestation and at time of delivery. The logistic regression analysis demonstrated that the distance between the internal os and the lower edge of the placenta between 18-24 weeks was the single significant variable associated with PP at term (p<0.001, odds ratio 0.319, 95% CI 0.20-0.50). However, excluding the distance from the regression model demonstrated other risk factors as previous miscarriage, previous cesarean section (CS), and history of multiple pregnancies and history of previous PP.Conclusions: About 5.0% of pregnant women have LIP at the second trimester of pregnancy (18-24 weeks) and only 25.0 % of them remain placenta previa at term. A cut-off value of 10 mm between the internal os and the lower edge of the placenta is the most important predictor of development of PP
Electrical Resistivity Imaging of a Coal Deposit at Tai Area of Gombe State, North Eastern Nigeria
A 2-D electrical resistivity imaging of some parts of Tai in Akko Local Government area of Gombe State, northeastern Nigeria was carried out. Tai is located 28 km from Pindiga and lies between latitudes 100 00′00″ and 100 06′00″N and longitudes 100 40′ 00″E and 10045′00″E. This study was prompted by a report that in the course of siting a hand-dug well and hand-pump borehole in Tai, coal seam was intercepted. The aim of this geoelectrical investigation is to image the survey area for possible location and future exploitation of coal seam found in the area. The survey was targeted at determining the lateral extent of the coal seam, resistivity values associated with the coal seam and depth to the coal seam. ABEM Terrameter SAS 1000 was used to acquire the data in this survey. The protocol chosen was the Wenner-Schlumberger array because of its sensitivity to both horizontal and vertical structures. Data processing was done using RES2DINV software. The results show that the resistivity values range from 3Ωm to 2033 Ωm. The top layer has resistivity ranges of about 66 Ωm to 2033 Ωm. Below this, is a layer of low resistivity ranging from 3 Ωm to 57 Ωm probably saturated with water. The layer with resistivity range of about 250 Ωm to 900 Ωm is probably the host of the coal seams. It can be concluded that the occurrence of the coal seam is probably more at the Northwest of the survey area and the coal seam is suspected to have resistivity values ranging from about 250 Ωm to 900 Ωm and depth varying from 3 m to 17.2 m. Keywords: Coal Seam, Lateral Extent, Electrical Resistivity Imagin
Recurrent spontaneous third-trimester uterine rupture after hysteroscopic resection of myoma: a case report
Uterine rupture is a catastrophic obstetrical emergency with serious effects on both women and fetuses. Operative hysteroscopic procedures can add more risk factor for occurrence of this tragedy. Here, we report a case of spontaneous recurrent rupture uterus at 33 weeks of gestation in a 32 years old woman with previous history of hysteroscopic resection of submucous myoma after development of acute abdomen. Uterine repair of fundal rupture was performed through emergency exploratory laparotomy. Surgeons should explain to their patients the hazards of probable risk of recurrent and multiple uterine rupture in the future pregnancy and to document this discussion in the medical records before proceeding to operative hysteroscopic procedures
Mechanical and Thermal Properties of Polyurethane-Palm Fronds Ash Composites
The aim of the article is to study the influence of environmentally friendly palm frond ash on the mechanical and thermal properties of polyurethane used as filler. Various weight filler ratios with particle sizes around (125 μm) were examined and characterized using elongation, tensile strength, Young's modulus, compressive strength, average burning time, and infrared spectroscopy. The results showed that the addition of 20 wt.% palm frond ash powder significantly improved the hardness mixture by about 2.83 MPa. In addition to that, the highest value of the compressive strength of the polymer with the additive was recorded at 10 wt.%. Also, the most excellent value of Young’s modulus was 2 MPa at a ratio of 50 wt. %, as was the average burning time of about 33 sec. The mechanical properties of polyurethane were affected by adding palm frond ash, which increases the tensile and compressive strengths, making it suitable for use in many applications. Moreover, the environmentally friendly material reflects the benefits of waste recycling. The addition of filler affects the morphology and strengthens the brittleness. Additionally, the use of fly ash from palm frond combustion in the technology of polyurethane materials complies. Partial replacement of petrochemical components with waste filler also reduces the total energy consumption in producing PU composites.
 
Antimicrobial activity of bBanana (Musa paradisiaca L.) peels against food borne pathogenic microbes
Banana (Musa paradisiaca L.) peels are usually considered as wastes and are
discarded during the processing, which eventually contribute to polluting the
environment. Hence, this study was aimed to evaluate the antimicrobial activity of two
different varieties of M. paradisiaca peels, i.e., Nangka (M. paradisiaca variety Nangka)
and Tanduk (M. paradisiaca variety Tanduk) with regard to generate safe and cheap
antimicrobials as well as address pollution related issues due to such wastes.
Antimicrobial study was carried out on the extracts using disc diffusion and broth
micro-dilution methods. The best activity through disc diffusion method for bacteria
and fungi was demonstrated by Tanduk peel’s ethanol and dichloromethane extracts
against S. aureus (30 mm) and C. krusei (10 mm), respectively. However, the least active
bacteria and fungi were found to be V. parahaemolyticus and C. albicans, respectively.
The minimum inhibitory concentration (MIC) values ranged from 6.25 to 100 mg/mL.
Tanduk peel’s ethanol extract exhibited the lowest MIC and minimum bactericidal
concentration (MBC) values against B. cepacia (6.25 mg/mL) whereas for fungi, Tanduk
peel’s dichloromethane extract exhibited lowest MIC and minimum fungicidal
concentration (MFC) values against C. albicans (25 mg/mL). The results of MBC or MFC
showed that some extracts were bactericidal or fungicidal while others were bacteriostatic
or fungistatic against certain microbes. Banana peel waste’s extracts could be potential
antimicrobial alternatives and may be effective to utilize as a natural source of
antimicrobial agent in pharmaceutical industries.
Key words: Musa paradisiaca L., Nangka, Tanduk, Antimicrobial activity, MIC, MBC, MFC
Knowledge about anesthesia and the role of anesthesiologists among Jeddah citizens
Background: The anesthesiologist has a vital role in the operating theatres. Awareness of the role of the anesthesiologist and the types of anesthesia is essential for every person. This study was made to estimate how much information the general population have about the anesthesiologist and the different types of anesthesia.Methods: This research was a cross sectional non-interventional study. The research team conducted a questionnaire in which each participant in the study was interviewed by the research team. The sample size was 159 participants.Results: From the participants,99 (62.2%) recognized the anesthesiologist as a specialized doctor who administers the anesthetics,62 (38.9%) know that the anesthesiologist has a role in resuscitating the patient with the team if crises occurred. However, 85 (53.4%) believe that the surgeon has the responsibility of postoperative pain management. Physicians were the source of knowledge for most participant’s information.Conclusions: A reasonable percentage of people appreciated the role of the anesthesiologist in administrating the anesthesia, however there is a lack of information about the role of the anesthesiologist intra and postoperatively. The need for more education for people about anesthesia is essential as the amount of information about anesthesia in general is rather low
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