A study of local approximation for polarization potentials

We discuss the derivation of an equivalent \textit{l}-independent polarization potential for use in the optical Schr\"{o}dinger equation that describes the elastic scattering of heavy ions. Three diffferent methods are used for this purpose. Application of our theory to the low energy scattering of the halo nucleus $^{11}$Li from a $^{12}$C target is made. It is found that the notion of \textit{l}-independent polarization potential has some validity but can not be a good substitute for the \textit{l}-dependent local equivalent Feshbach polarization potential.Comment: 8 pages, 4 figure

Parameter Optimisation of Carbon Nanotubes Synthesis via Hexane Decomposition over Minerals Generated from Anadara granosa

The synthesis of carbon nanotubes (CNTs) by the chemical vapour deposition (CVD) method using natural calcite from Anadara granosa shells as the metal catalyst support was studied. Hexane and iron (Fe) were used as the carbon precursor and the active component of the catalyst, respectively. Response surface methodology (RSM) based on central composite design (CCD) was used to optimise the effect of total iron loading, the duration of reaction, and reaction temperature. The optimal conditions were total iron loading of 7.5%, a reaction time of 45 min, and a temperature of 850°C with a resulting carbon yield of 131.62%. Raman spectra, field-emission-scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses showed that the CNTs were of the multiwalled type (MWNTs)

Role of virtual break-up of projectile in astrophysical fusion reactions

We study the effect of virtual Coulomb break-up, commonly known as the dipole polarizability, of the deuteron projectile on the astrophysical fusion reaction 3He(d,p)4He. We use the adiabatic approximation to estimate the potential shift due to the E1 transition to the continuum states in the deuteron, and compute the barrier penetrability in the WKB approximation. We find that the enhancement of the penetrability due to the deuteron break-up is too small to resolve the longstanding puzzle observed in laboratory measurements that the electron screening effect is surprisingly larger than theoretical prediction based on an atomic physics model. The effect of the 3He break-up in the 3He(d,p)4He reaction, as well as the 7Li break-up in the 7Li(p,alpha)4He reaction is also discussed.Comment: 9 pages, 2 eps figure

Review on fixed-frequency beam steering for leaky wave antenna

This paper aims to survey the efforts of researchers in response to the novel and effective technology of control radiation pattern at a fixed frequency for leaky wave antenna (LWA), map the research landscape from the literature onto coherent taxonomy and determine the basic properties of this potential field. In addition, this paper investigates the motivation behind using beam steering in LWA and the open challenges that impede the utility of this antenna design. This paper offers valuable recommendations to improve beam steering in LWA. The review revealed the development and improvement of several techniques of beam scanning LWA. However, several areas or aspects require further attention. All the articles, regardless of their research focus, attempt to address the challenges that impede the full utility of beam scanning and offer recommendations to mitigate their drawbacks. This paper contributes to this area of research by providing a detailed review of the available options and problems to allow other researchers and participants to further develop beam scanning. The new directions for this research are also described

Radiation beam scanning for leaky wave antenna by using slots

This paper provides an insight of a new, microstrip leaky wave antenna. It holds the ability to continue steer its beam at a swapping frequency. This is done with acceptable impedance matching while scanning and very little gain variation. Investigation is carried out on LWAs’ control radiation pattern in steps at a band frequency via vertical and horizontal slots. The enhancement is realized by etching horizontal and vertical slots on the radiation element. This study also presents a novel half-width microstrip leaky wave antenna (LWA). The antenna is made up of the following basic structures group’s vertical and horizontal slots. The reactance profile at the microstrip’s free edge and thus the main beam direction is changed once the control-cell states are changed. The radiation pattern direction changes by sweeping the operating frequency between 4 GHz to 6 GHz.The main beam may be directed by the antenna between 15o and 55o. C band achieved the measured peak gain of the antenna of 10 dBi at 4.3 GHz beam scanning range

Cancer in Children at El Obeid Hospital, Western Sudan.

Background: Cancers form one of the major causes of death in children. They differ markedly from adult cancers in their nature, distribution and prognosis. Objectives: To determine the pattern of childhood cancer at El Obeid Hospital, Western Sudan. Patients and Methods: The records of all patients admitted with cancer aged 15 years and below tothe wards of El Obeid Hospital, Western Sudan over two years were studied. The cancers were classified according to the organs affected and then ranked in their order of relative frequency. The mean age, age range, gender and the relative frequency rates were calculated. Results: There were 40 newly diagnosed childhood cancer patients during the study period. Males were 29 patients (72.5%). The age ranged three months to 14 years. Leukaemias were the most common malignancy in both sexes, followed by bone tumours and then nephroblastoma.Conclusions: Cancers in children were seen at Western Sudan, and cases admitted to hospital only reflect the tip of the iceberg as many cases were directly referred to Oncology Hospitals. Establishment of a local radiation and isotopes centre is needed in this part of the country to provide oncology services and to integrate preventive programs.Key words: Acute lymphocytic leukaemia, osteosarcoma, nephroblastoma, Western Sudan

Interplay of static and dynamic effects in 6He+ 238U Fusion

We investigate the influence of the neutron halo and the breakup channel in 6He + 238U fusion at near-barrier energies. To include static effects of the 2n-halo in 6He nuclei, we use a single-folding potential obtained from an appropriate nucleon-238U interaction and a realistic 6He density. Dynamical effects arising from the breakup process are then included through coupled-channel calculations. These calculations suggest that static effects dominate the cross section at energies above the Coulomb barrier, while the sub-barrier fusion cross section appears to be determined by coupling to the breakup channel. This last conclusion is uncertain due to the procedure employed to measure the fusion cross-section.Comment: 13 pages, 4 figure

Osteoprotegerin, sclerostin, and osteocalcin serum levels in thyroid disorder patients

The maintenance of thyroid hormone homeostasis is essential in the regulation of skeletal system development, bone tissue mineralization and fracture risk prevention. This study was carried out to evaluate the serum level of osteoprotegerin (OPG), sclerostin (SOST), and osteocalcin (OC) in hypo- and hyperthyroidism patients. A total number of examined patients was 90 individuals, 30 of them were normal as a control group, the rest 60 individuals were arranged in two groups: 30 patients with hypothyroidism and 30 patients with hyperthyroidism. Serum assay tests for OPG, SOST, OC, thyroid stimulating hormone (TSH), total triiodothyronine (T3), and total thyroxine (T4) were used. The present study reported high levels of SOST, T3, and T4 and low levels of OPG, OC, and TSH in patients with hyperthyroidism compared to control. Whereas in patients with hypothyroidism only SOST and TSH levels were increased, but OPG, OC, T3, and T4 levels were low compared to control. The data obtained indicate the correlation on osteoprotegerin, sclerostin, and osteocalcin levels with thyroid hormones disturbances

Simple broadband circularly polarized monopole antenna with two asymmetrically connected U-shaped parasitic strips and defective ground plane

A simple compact broadband circularly polarized monopole antenna, which comprises a simple monopole, a modified ground plane with an implementing triangular stub and two asymmetrically connected U-shaped parasitic strips, is proposed. Simulation results show that the proposed compact antenna (0.62λo×0.68λo) achieves a 10-dB impedance bandwidth (IBW) of 111% (1.7 to 5.95 GHz) and a 3-dB axial ratio bandwidth (ARBW) of 61% (3.3–6.2 GHz) with a peak gain between 2.9–4 dBi for the entire ARBW. With its broad IBW and ARBW, compact size and simple structure, the proposed antenna is suitable for different wireless communications

Comparison of arch form between ethnic Malays and Malaysian Aborigines in Peninsular Malaysia

Objective: To determine and compare the frequency distribution of various arch shapes in ethnic Malays and Malaysian Aborigines in Peninsular Malaysia and to investigate the morphological differences of arch form between these two ethnic groups. Methods: We examined 120 ethnic Malay study models (60 maxillary, 60 mandibular) and 129 Malaysian Aboriginal study models (66 maxillary, 63 mandibular). We marked 18 buccal tips and incisor line angles on each model, and digitized them using 2-dimensional coordinate system. Dental arches were classified as square, ovoid, or tapered by printing the scanned images and superimposing Orthoform arch templates on them. Results: The most common maxillary arch shape in both ethnic groups was ovoid, as was the most common mandibular arch shape among ethnic Malay females. The rarest arch shape was square. Chi-square tests, indicated that only the distribution of the mandibular arch shape was significantly different between groups (p = 0.040). However, when compared using independent t-tests, there was no difference in the mean value of arch width between groups. Arch shape distribution was not different between genders of either ethnic group, except for the mandibular arch of ethnic Malays. Conclusions: Ethnic Malays and Malaysian Aborigines have similar dental arch dimensions and shapes. Korean J Orthod 2012;42(1):47-54. This record was migrated from the OpenDepot repository service in June, 2017 before shutting down