Dirac particle in Aharonov–Bohm–Coulomb field: Path integral treatment

Exact Green’s function related to a Dirac particle submitted to the combination of Aharonov–Bohm and Coulomb potentials in [Formula: see text]) coordinate space is analytically calculated via path integral formalism. The Pauli matrices which describe the spin dynamics are replaced by two fermionic oscillators via the Schwinger model. The energy spectrum as well as the corresponding normalized wave functions are extracted following this approach. The interesting properties of the spinors are thus deduced after symmetrization. According to the symmetric form for Green’s function, it is shown that the non-relativistic limit of the Dirac particle is undertaken with much ease.

Assessing an Integral Treatment for Landfill Leachate Reverse Osmosis Concentrate

An integral treatment process for landfill leachate reverse osmosis concentrate (LLROC) is herein designed and assessed aiming to reduce organic matter content and conductivity, as well as to increase its biodegradability. The process consists of three steps. The first one is a coagulation/flocculation treatment, which best results were obtained using a dosage of 5 g L−1 of ferric chloride at an initial pH = 6 (removal of the 76% chemical oxygen demand (COD), 57% specific ultraviolet absorption (SUVA), and 92% color). The second step is a photo-Fenton process, which resulted in an enhanced biodegradability (i.e., the ratio between the biochemical oxygen demand (BOD5) and the COD increased from 0.06 to 0.4), and an extra 43% of the COD was removed at the best trialed reaction conditions of [H2O2]/COD = 1.06, pH = 4 and [H2O2]/[Fe]mol = 45. An ultra violet-A light emitting diode (UVA-LED) lamp was tested and compared to conventional high-pressure mercury vapor lamps, achieving a 16% power consumption reduction. Finally, an optimized 30 g L−1 lime treatment was implemented, which reduced conductivity by a 43%, and the contents of sulfate, total nitrogen, chloride, and metals by 90%. Overall, the integral treatment of LLROC achieved the removal of 99.9% color, 90% COD, 90% sulfate, 90% nitrogen, 86% Al, 77% Zn, 84% Mn, 99% Mg, and 98% Si; and significantly increased biodegradability up to BOD5/COD = 0.4.

Integral treatment of butt joints for the fatigue life assessment in the low cycle fatigue regime

The framework for a fatigue assessment of welded joints under service loading conditions of crane structures from the low cycle to the high cycle fatigue regime includes the consideration of elastic-plastic material behavior, variable amplitude loading, and acceptable calculation times. Therefore, an integral treatment of butt joints has been developed for fatigue life estimation. The butt weld is considered in its entirety, so that it can be described by its cyclic behavior. The evaluation of the cyclic stress-strain behavior and tri-linear strain-life curves of butt joints for different high-strength, fine-grained structural steels, derived by strain-controlled fatigue tests, is the basis for this description. This procedure is not limited to conventionally applied gas metal arc welding only, but also the fatigue assessment of laser beam welding is possible, for example. Cyclic transient effects have been analyzed and a distinctive cyclic softening is described by linearization of Ramberg-Osgood parameters, depending on the damage content of each cycle derived from constant amplitude, strain-controlled tests. On the basis of the cyclic behavior in combination with memory and Masing behavior, a simulation of the stress-strain paths of investigated butt welds, under constant and variable amplitude loading, has been performed. Damage parameters are used to accumulate the damage cycle by cycle in order to derive the fatigue lifetime. Finally, calculated fatigue lives were compared with experimentally determined lives, showing the impact of this procedure.

Photodynamic Therapy in 2020: Lights in the Darkness

Photodynamic therapy (PDT) is an integral treatment modality for treating the entire process of photodamage, based on what is understood about the pathogenesis of actinic keratosis and the consequences from treating only visible spots and not the underlying disease. Dermatologists must consider incorporation of treatment in combination with duration, frequency, and tolerability of local skin reactions. These considerations are important, along with the combination of topical therapies and intermittent cryotherapy of individual actinic keratoses. Aside from costs and patient demographics, adaptation by dermatologists can influence variability in long-term treatment algorithms. There are multiple published guidelines and consensus statements for the US and Europe to promote safe incorporation of both blueand red light along with the variable concentrations of ALA by dermatologists. However, there is a lack of head to head studies and comparative superiority as well as any evidence to support the use of topical agents. As management of local skin reactions becomes more commonplace, so will improved management of PDT to foster patient safety.

Sequential ‘acid leaching–anion exchange–aerobic composting’ process for recycle of municipal sludge

Municipal sludge disposal and recycle has become a prominent research theme. In this study, a sequential process for integral treatment of municipal sludge was primarily presented, combining acid leaching, anion exchange and aerobic composting. The aim of the process was to remove chromium (Cr) from the sludge and reuse the sludge as manure. Firstly, Cr was removed from municipal sludge via the acid leaching process; the removal rate was up to 57.43%. Then, ion exchange resin was used to remove Cr from leachate; the removal rate reached 95%. Aluminum sheet was used to replace the Cr from eluent; the replacement rate was 63.3%. The aerobic composting process could be successfully warmed up to above 55 °C and lasted for 4 days; the seed germination index reached 68.3%. After the composting process, the residual Cr in sludge mainly existed at a more stable residual state and organic binding state. Overall, this novel sequential process serves as a potential high-efficiency, green, low-energy way for municipal sludge recycle.