46 research outputs found

    Cryptoanalysis of RSA variants with special structure of RSA primes

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    In this paper, we present attacks on three types of RSA modulus when the least significant bits of the prime factors of RSA modulus satisfy some conditions. Let p,p, and qq be primes of the form p=am1+rpp=a^{m_1}+r_p and q=bm2+rqq=b^{m_2}+r_q respectively, where a,b,m1,m2∈Z+a,b,m_{1},m_{2} \in \mathbb{Z^+} rp,r_p, and rq r_q are known. The first attack is when the RSA modulus is N=pqN=pq where m1m_1 or m2m_2 is an even number. If (rprq)12\left(r_{p}r_{q}\right)^\frac{1}{2} is sufficiently small, then NN can be factored in polynomial time. The second attack is when N=psq,N=p^{s}q, where q>pq>p and ss divides m2.m_2. If rprqr_pr_q is sufficiently small, then NN can be factored in polynomial time. The third attack is when N=ps+lqs,N=p^{s+l}q^{s}, where p>q,p>q, s,l∈Z+,s,l \in \mathbb{Z^+}, l<s2l < \frac{s}{2} and ss divides m1l.m_1l. If am1>qam1ls,a^{m_1}>qa^{\frac{m_1l}{s}}, and lrp3lr^3_p is sufficiently small, then NN can be factored in polynomial time

    Magnetic Resonance-based Response Assessment and Dose Adaptation in Human Papilloma Virus Positive Tumors of the Oropharynx treated with Radiotherapy (MR-ADAPTOR): An R-IDEAL stage 2a-2b/Bayesian phase II trial.

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    Background Current standard radiotherapy for oropharynx cancer (OPC) is associated with high rates of severe toxicities, shown to adversely impact patients' quality of life. Given excellent outcomes of human papilloma virus (HPV)-associated OPC and long-term survival of these typically young patients, treatment de-intensification aimed at improving survivorship while maintaining excellent disease control is now a central concern. The recent implementation of magnetic resonance image - guided radiotherapy (MRgRT) systems allows for individual tumor response assessment during treatment and offers possibility of personalized dose-reduction. In this 2-stage Bayesian phase II study, we propose to examine weekly radiotherapy dose-adaptation based on magnetic resonance imaging (MRI) evaluated tumor response. Individual patient's plan will be designed to optimize dose reduction to organs at risk and minimize locoregional failure probability based on serial MRI during RT. Our primary aim is to assess the non-inferiority of MRgRT dose adaptation for patients with low risk HPV-associated OPC compared to historical control, as measured by Bayesian posterior probability of locoregional control (LRC).Methods Patients with T1-2 N0-2b (as per AJCC 7th Edition) HPV-positive OPC, with lymph node <3 cm and <10 pack-year smoking history planned for curative radiotherapy alone to a dose of 70 Gy in 33 fractions will be eligible. All patients will undergo pre-treatment MRI and at least weekly intra-treatment MRI. Patients undergoing MRgRT will have weekly adaptation of high dose planning target volume based on gross tumor volume response. The stage 1 of this study will enroll 15 patients to MRgRT dose adaptation. If LRC at 6 months with MRgRT dose adaptation is found sufficiently safe as per the Bayesian model, stage 2 of the protocol will expand enrollment to an additional 60 patients, randomized to either MRgRT or standard IMRT.Discussion Multiple methods for safe treatment de-escalation in patients with HPV-positive OPC are currently being studied. By leveraging the ability of advanced MRI techniques to visualize tumor and soft tissues through the course of treatment, this protocol proposes a workflow for safe personalized radiation dose-reduction in good responders with radiosensitive tumors, while ensuring tumoricidal dose to more radioresistant tumors. MRgRT dose adaptation could translate in reduced long term radiation toxicities and improved survivorship while maintaining excellent LRC outcomes in favorable OPC.Trial registration ClinicalTrials.gov ID: NCT03224000; Registration date: 07/21/2017

    Cost-Effective and High Purity Valuable Metals Extraction from Water Leaching Solid Residues Obtained as a By-Product from Processing the Egyptian Boiler Ash

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    The water leaching solid residues (WLSR) obtained from salt-roasting Egyptian boiler ash are considered an essential secondary resource for (13%) nickel and (5.6%) zinc extraction. Hence, the current study aims for the cost-effective and high purity Ni, Zn, Fe and Mg metal ion extraction from (WLSR) using a sulfuric acid leaching process. The factors affecting the percentage recovery of Ni, Zn, Fe and Mg from WLSR, including leaching temperature, time, acid concentration and solid/liquid ratio, have been investigated. The obtained leaching solutions were analyzed chemically using ICP, and the different precipitates were analyzed mineralogically using XRD and EDX analysis and chemically using XRF. The maximum percentage recovery of Ni, Zn, Fe and Mg was 95.02%, 90.13%, 66.29% and 75.73%, which was obtained under the optimum leaching conditions of 8% H2SO4 concentration and 1/15 solid/liquid ratio at 85 &deg;C for 240 min. The effect of pH, Fe2O3 dosage as nucleating agent and the precipitation duration on iron removal and Ni and Zn loss have been thoroughly studied. It has been found that &gt;95% of the contained iron impurity can be removed, while nickel and zinc losses are around 4.2% and 3.8%, respectively. Additionally, a pH of 6 and 0.45 mol/L concentration of H2C2O4 was utilized to precipitate Mg as MgC2O4.2H2O, demonstrating that the precipitation efficiency of Mg reaches 96.9%. Nickel and zinc precipitation efficiency was 92.25% and 85.51%, respectively, by raising the solution pH to approximately 9. The kinetic of Ni and Zn dissolution has been investigated to explain the mechanism prevalent and the factors influencing the leaching process. It has been found that the nickel leaching kinetic is controlled by both diffusion through an inert porous layer and by chemical reaction with an activation energy of 20.25 kJ.mol&minus;1. Meanwhile, the kinetic of zinc leaching is controlled by solid product layer diffusion with an activation energy of 11.67 kJ mol&minus;1

    Cost-Effective and High Purity Valuable Metals Extraction from Water Leaching Solid Residues Obtained as a By-Product from Processing the Egyptian Boiler Ash

    No full text
    The water leaching solid residues (WLSR) obtained from salt-roasting Egyptian boiler ash are considered an essential secondary resource for (13%) nickel and (5.6%) zinc extraction. Hence, the current study aims for the cost-effective and high purity Ni, Zn, Fe and Mg metal ion extraction from (WLSR) using a sulfuric acid leaching process. The factors affecting the percentage recovery of Ni, Zn, Fe and Mg from WLSR, including leaching temperature, time, acid concentration and solid/liquid ratio, have been investigated. The obtained leaching solutions were analyzed chemically using ICP, and the different precipitates were analyzed mineralogically using XRD and EDX analysis and chemically using XRF. The maximum percentage recovery of Ni, Zn, Fe and Mg was 95.02%, 90.13%, 66.29% and 75.73%, which was obtained under the optimum leaching conditions of 8% H2SO4 concentration and 1/15 solid/liquid ratio at 85 °C for 240 min. The effect of pH, Fe2O3 dosage as nucleating agent and the precipitation duration on iron removal and Ni and Zn loss have been thoroughly studied. It has been found that >95% of the contained iron impurity can be removed, while nickel and zinc losses are around 4.2% and 3.8%, respectively. Additionally, a pH of 6 and 0.45 mol/L concentration of H2C2O4 was utilized to precipitate Mg as MgC2O4.2H2O, demonstrating that the precipitation efficiency of Mg reaches 96.9%. Nickel and zinc precipitation efficiency was 92.25% and 85.51%, respectively, by raising the solution pH to approximately 9. The kinetic of Ni and Zn dissolution has been investigated to explain the mechanism prevalent and the factors influencing the leaching process. It has been found that the nickel leaching kinetic is controlled by both diffusion through an inert porous layer and by chemical reaction with an activation energy of 20.25 kJ.mol−1. Meanwhile, the kinetic of zinc leaching is controlled by solid product layer diffusion with an activation energy of 11.67 kJ mol−1

    Automated Functional Safety Analysis of Automated Driving Systems

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    In this paper, we present a method to assess functional safety of architectures for Automated Driving Systems (ADS). The ISO 26262 standard defines requirements and processes in support of achieving functional safety of passenger vehicles, but does not address in particular autonomous driving functions. Autonomous driving will bring with it a number of fundamental changes affecting functional safety. First, there will no longer be a driver capable of controlling the vehicle in case of a failure of the ADS. Second, the hardware and software architectures will become more complex and flexible than those used for conventional vehicles. We present an automated method to assert functional safety of ADS systems in the spirit of ISO 26262 in light of these changes. The approach is model-based and implemented in the QuantUM analysis tool. We illustrate its use in functional safety analysis using a proposed practical ADS architecture and address, in particular, architectural variant analysis.publishe

    Selective Recovery of Cadmium, Cobalt, and Nickel from Spent Ni–Cd Batteries Using Adogen<sup>®</sup> 464 and Mesoporous Silica Derivatives

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    Spent Ni–Cd batteries are now considered an important source for many valuable metals. The recovery of cadmium, cobalt, and nickel from spent Ni–Cd Batteries has been performed in this study. The optimum leaching process was achieved using 20% H2SO4, solid/liquid (S/L) 1/5 at 80 °C for 6 h. The leaching efficiency of Fe, Cd, and Co was nearly 100%, whereas the leaching efficiency of Ni was 95%. The recovery of the concerned elements was attained using successive different separation techniques. Cd(II) ions were extracted by a solvent, namely, Adogen® 464, and precipitated as CdS with 0.5% Na2S solution at pH of 1.25 and room temperature. The extraction process corresponded to pseudo-2nd-order. The prepared PTU-MS silica was applied for adsorption of Co(II) ions from aqueous solution, while the desorption process was performed using 0.3 M H2SO4. Cobalt was precipitated at pH 9.0 as Co(OH)2 using NH4OH. The kinetic and thermodynamic parameters were also investigated. Nickel was directly precipitated at pH 8.25 using a 10% NaOH solution at ambient temperature. FTIR, SEM, and EDX confirm the structure of the products

    Zirconium oxide with graphene oxide anchoring for improved heavy metal ions adsorption: Isotherm and kinetic study

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    Heavy metal contamination is a major environmental issue worldwide and a significant public health risk. However, developing environmentally sustainable and technically viable solutions or adsorbents for treating water contamination caused by heavy metals is urgently needed. In this work, an eco-friendly approach of obtaining a new composite material called ZrO2/GO that was prepared from the synthesized nano zirconium oxide (ZrO2) and graphene oxide (GO) prepared from spent carbon rods in zinc carbon batteries. ZrO2/GO was analyzed by XRD, SEM, BET, EDX, and FTIR to learn more about its composition and structure. The batch approach determined the optimal sorption conditions, including pH4, 50 mg ZrO2/GO, 150 mg/L U(VI), and 50 min of sorption time. ZrO2/GO was found to have a 128 mg/g sorption capacity. The Langmuir and 2nd-order kinetic equations can be exploited to elucidate the adsorption approach with reasonable accuracy. Since sorption is exothermic when it occurs naturally, thermodynamic restrictions were also envisioned. ZrO2/GO retains over 92% heavy metal ions (VI) removal efficiency even after 7 cycles. ZrO2/GO shows assurance as a potent sorbent material to extract hexavalent heavy metal ions and adsorption capacity from massive solution volumes
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