A comparative study using direct hydrothermal and indirect fusion methods to produce zeolites from coal fly ash utilizing single-mode microwave energy

This paper investigates the effects of microwave irradiation on the synthesis of zeolite Na-A from coal fly ash at atmospheric pressure. Microwave irradiation has shown to accelerate zeolitization from several hours to several minutes. A single-mode laboratory-scale microwave was employed, which enabled control of irradiated power and temperature of the reaction mixture, while the pressure was controlled by affixing a condenser on the 40 mL Teflon reactor vessel with a working volume 20 mL. Design of Experiment was used to compare two methods of converting CFA to zeolite-A, direct hydrothermal method and indirect fusion method. Experiments conducted were two level four factorial designs. The first factor considered was the categorical factor of conversion method (hydrothermal vs fusion), while the other three factors investigated were power (P), time (θ), and aluminate concentration (δ). Zeolite produced from CFA (CFAZA) was characterized using XRD, FTIR, SEM, TGA, BET, and cation exchange capacity. It was observed that the crystallinity of the product was influenced by factors such as, conversion method, power, time, and aluminate concentration. The hydrothermal and fusion products were comparable to each other in their characteristics, however, hydrothermal CFAZA performed better at immobilizing heavy metal ions and showed better crystalline structure, whereas fusion CFAZA had a higher BET surface area and a slightly higher CEC. Regardless of the performance of the categorical factors the other factors, i.e., power, time, and aluminate concentration followed the same trend for both types of CFAZA.     

Building information modeling for sustainable design and LEED rating analysis

Today, there is a high level of demand for sustainable buildings. The most important decisions regarding a building's sustainable features are made during the design and preconstruction stages. Leadership in Energy and Environmental Design (LEED^®) is the most widely adopted sustainable building rating system in the United States. For projects pursuing LEED^® certification, designers have to conduct in-depth sustainability analyses based on a building's form, materials, context, and mechanical-electrical-plumbing (MEP) systems. Since Building Information Modeling (BIM) allows for multi-disciplinary information to be superimposed within one model, it creates an opportunity to conduct these analyses accurately and efficiently as compared to the traditional methods. In this exploratory research, a case study was conducted on Salisbury University's Perdue School of Business building to demonstrate the use of BIM for sustainable design and the LEED^® certification process. First, a conceptual framework was developed to establish the relationship between BIM-based sustainability analyses and the LEED^® certification process. Next, the framework was validated via this case study. The results of this study indicate that documentation supporting LEED^® credits may be directly or indirectly prepared using the results of BIM-based sustainability analyses software. This process could streamline the LEED^® certification process and save substantial time and resources which would otherwise be required using traditional methods.     

Influence of Y~(3+),Yb~(3+),Gd~(3+) cations on structural and electromagnetic properties of CuFe_2O_4 nanoferrites prepared via one step sol-gel method

Rare earths(REs) play a key role in distorting spinel structure by creating some defects at the lattice sites and make them suitable for magnetodielectric applications.In the present study,the nanoferrites of CuRE_(0.02)Fe_(1.98)O_4,where REs=Y~(3+),Yb~(3+),Gd~(3+),were prepared using one step sol-gel method.The prepared samples are copper ferrite(CFO),yttrium doped copper ferrite(Y-CFO),ytterbium doped copper ferrite(Yb-CFO) and gadolinium doped copper ferrite(Gd-CFO),respectively.The single-phase structure of all the REs doped nanoferrites was determined by X-ray diffraction(XRD) analysis.The porosity,agglomerations and grain size of the REs doped copper ferrite were examined using field emission scanning electron microscopy(FESEM) analysis.Fourier transform infrared spectroscopy(FTIR)elaborates the phase formation and environmental effects on the REs doped nanoparticles(NPs).The recorded room temperature M-H loops from a vibrating sample magnetometer(VSM) elucidate the magnetic properties of the REs doped spinel nanoferrites.The magnetic saturation(M_s) was calculated in the range of 23.08 to 51.78 emu/g.The calculated coercivity values(272.6 to 705.60 Oe) confirm the soft magnetic behavior of REs doped copper ferrites.Furthermore,the electromagnetic and dielectric properties were assessed using a Vector network analyzer(VNA) from 1 to 6 GHz.The permeability,permittivity,dielectric tangent loss and electric modulus of the REs doped spinel ferrites illustrate that the prepared NPs may be suitable for microwave and high frequency applications.     

Inhibition of FLT3: A Prototype for Molecular Targeted Therapy in Acute Myeloid Leukemia

Modern therapy of acute myeloid leukemia (AML) began in 1973 with the first report of the successful combination of daunorubicin and cytarabine, which led to complete remission in approximately 45% of patients. Accurate AML diagnosis was dependent on morphology, aided initially only by cytochemistry. Unlike acute lymphoblastic leukemia (ALL), immunophenotyping offered little in the diagnosis of AML, at least during the 1970s and 1980s. The advent of reliable cytogenetics changed the entire prognostic outlook of AML. With karyotypic analysis, different groups of AML could be classified and stratified for various therapies. Unique mutational profiling was a major advance in further categorizing AML patients, aided by the immunophenotypic identification of antigenic markers on the cells. All these advances were occurring as the understanding of the importance of the tumor burden—known as minimal residual disease (MRD)—became crucial for the management of AML patients. The efficacy of MRD has rapidly progressed in the past decade, from a specificity of 10⁻³ with immunophenotyping to 10⁻⁴ with polymerase chain reaction (PCR), which is only appropriate for some patients with AML, and finally to 10⁻⁵ or even 10⁻⁶ cells with the extraordinary sensitivity of next-generation sequencing (NGS). All of these advances have promoted the concept of personalized medicine, which has led to the advent of targeted agents that can accurately be used for specific diagnostic subtypes. Responses can be predicted and measured accurately. Such targeted agents have now become a cornerstone in the management of AML, increasing efficacy and dramatically reducing toxicity. The focus of this review is on one of the most well-studied targeted agents in AML: the FMS-like tyrosine kinase 3 (FLT3) inhibitors, which have impacted the prognostication and therapeutics of AML. This review selectively discusses the FLT3 inhibitors in detail, as a model for the other burgeoning targeted agents that have already been approved, as well as those that are currently in development.     

Safety analysis for core conversion (from HEU to LEU) of Pakistan research reactor-2 (PARR-2)

PARR-2 (Pakistan Research Reactor-2), an MNSR (Miniature Neutron Source Reactor) is to be converted from HEU (High Enriched Uranium) to LEU (Low Enriched Uranium) fuel, along with all current MNSRs in various other countries. The purpose of conversion is to minimize the use of HEU for non-proliferation of high-grade nuclear fuel. The present report presents thermal hydraulic and safety analyses of PARR-2 using existing HEU fuel as well as proposed LEU fuel. Presently, the core is comprised of 90.2% enriched UAl₄-Al fuel. There are 344 fuel pins of 5.5 mm diameter. The core has a total of 994.8 g of U²³⁵. Standard computer code PARET/ANL (version 1992) (Obenchain, 1969) was employed to perform steady-state and transient analyses. Various parameters were computed, which included: coolant outlet, maximum clad surface & maximum fuel centerline temperatures; and peak power & corresponding peak core temperatures resulting from a transient initiated by 4 mK positive reactivity insertion. Results were compared with the reported data in Final Safety Analysis Report (FSAR) (Qazi et al., 1994). It was found that the PARET results were in reasonable agreement with the manufacturer's results. Calculations were also carried out for the proposed LEU core with two suggested fuel pin sizes (5.5 mm and 5.1 mm diameter with 12.6% & 12.3% enrichment, respectively). Comparison of the LEU results with the existing HEU fuel has been made and discussed.     

Experimental Study on Hybrid Cryogenic and Plasma-Enhanced Turning of 17-4PH Stainless Steel

This article presents machinability of 17-4PH stainless steel using a hybrid technique composed of plasma-enhanced turning and cryogenic turning. First of all, using some primary experimental tests and nonlinear regression, a mathematical model was developed for surface temperature of uncut chip as a function of plasma current and cutting parameters. Then, the influence of cutting speed (V_c), feed (f), and surface temperature of uncut chip (T_sm) was studied on surface roughness (R_a), cutting force (F_z), and tool flank wear (V_B). The results show that hybrid turning (HYT) is able to lower the main cutting force and tool flank wear in comparison with conventional turning. In addition, surface roughness was improved except for high level of surface temperature of uncut chip. However, hardness measurement of machined workpiece showed that HYT does not change the hardness of machined surface.     

Analytical Solution for Wave Propagation Due to Pop-Out Phenomenon in Solid Expandable Tubular Technology

Solid expandable tubular technology has gained wide acceptance in the petroleum industry due to its operationally simplified and cost-effective solution in well drilling. The down-hole hydraulic expansion results in forward motion of a mandrel until it pops out of the tubular. The pop-out phenomenon, which occurs at the end of the tubular expansion process, leads to a sudden release of stored energy within a fluid-tubular system, causing unnecessary vibration. These vibrations can become severe and may cause permanent damage to the tubular. Hence, a complete understanding of the dynamics of the fluid-tubular system is essential to avoid premature failure.

This paper focuses on the development of a mathematical model describing the dynamics of a fluid-tubular system due to pop-out phenomenon. The coupling between tubular, fluids, and formation is incorporated. An analytical solution for the propagation of displacement, stress, and pressure waves, originating due to the excitation caused by pop-out, is obtained. The model also identifies the potential failure locations along the tubular. The coupling effect is more prominent if the tubular material is elastic as compared to elastic-perfectly plastic material. A sensitivity analysis showed that the coupling effects vanish with increase in tubular stiffness and reach an asymptotic value with an increase in formation stiffness. The quantification of coupling effects is important in order to see the effects of pressure waves on the other subsystems present down hole.     

Technetium-99m-MIBI myocardial SPECT: supine versus right lateral imaging and comparison with coronary arteriography

Myocardial perfusion SPECT using the prone position improves inferior wall counts and decreases motion problems as compared with the usual supine position. Nonetheless, it is not suitable for women. In addition, it is associated with artifactual anteroseptal defects and hot spots. METHODS: The right lateral (RL) position was evaluated instead of the prone position in 72 patients (26 women). RL imaging was performed immediately after the supine imaging during a routine 2-day 99mTc-sestamibi exercise protocol. The SPECT images were scored semiquantitatively by three physicians. Moreover, regional myocardial counts, as well as extent and severity of defects, were assessed by quantitative polar map analysis. RESULTS: All patients tolerated the RL position well and there was no significant patient movement in either position. Higher inferior myocardial counts per pixel were observed in the RL than in supine images. Inferior wall defects (especially mild ones) were more common in the supine than the RL images, whereas defects in other regions were not different. Quantitative analysis confirmed these findings. Analysis of 34 patients with recent coronary arteriography revealed an overall coronary artery disease (CAD) supine- and RL-imaging specificity of 50% and 75%, respectively, and the sensitivities of both were 93%. Right CAD sensitivity, specificity and normalcy rates for the supine position were 100%, 44% and 55%, whereas those of the RL position were 94%, 75% and 90%, respectively. CONCLUSION: The RL position improves CAD diagnostic accuracy, particularly right CAD, without significant artifacts in other myocardial regions. Unlike the prone position, the RL position is well tolerated by both women and men.     

Superfluid density and critical current of3He in confined geometries

Superfluid³He in severely confined geometries is studied in the Ginzburg-Landau limit. Both A and B phases are analyzed in narrow slabs and in small cylinders. Physically measurable quantities include the superfluid density and the critical current, which are significantly suppressed by the boundaries. Related alterations in the phase diagram are also considered. For small lateral dimensions, the A phase can be favored even well below the polycritical pressure.     

Characterization of glass-ceramic corrosion and durability

The chemical durability of some selected glass-ceramic materials based on the Li₂O- (MnO, CaO)MgO---Al₂O₃---SiO₂ glass composition, has been determined by HCl, using the powder test.

The leachability of the glass-ceramic was gradually increased by replacing MgO with MnO, while it was decreased by addition of MnO instead of CaO. Calcium oxide had a retarding effect on the durability of the material when it was added instead of MgO and/or MnO. However, on the addition of Al₂O₃ in replacing Li₂O, the durability of the material was markedly improved. The leaching data were found to be dependent mainly on the proportion of the glass oxide constituents i.e. MgO/MnO, CaO/MnO and Li₂O/Al₂O₃ ratios present in the glasses.

The results were correlated to different views concerning the effect of various ions on the rate of interdiffusion between the crystalline-glass materials and leaching solution, the type, and proportions of the crystalline phases developed in glass-ceramics and residual glass phase.