Derivatization of keto fatty acids: VI. Synthesis,oxidation and mass spectrometry of dithiolanes

The synthesis of alkyl chain-substituted dithiolanes, bisdithiolane and disulfolanes from oxo acids and their decomposition to original oxo acids are described. Reactions of ethanedithiol with 2 oxo esters, methyl 10-oxoundecanoate and methyl 12-oxooctadecanoate, give excellent yield of the corresponding dithiolanes, which are oxidized to the respective disulfolanes by m-chloroperbenzoic acid (m-CPBA). A similar reaction of ethanedithiol with methyl 9,10-dioxooctadecanoate affords bisdithiolane. Retroreactions of the dithiolanes and bisdithiolanes under acidic conditions and of disulfolanes under alkaline conditions yield the parent oxo acids. The structures of the individual reaction products have been established from analytical and spectral data and confirmed by a study of their mass spectra.     

Internet of things and cloud computing‐based energy management system for demand side management in smart grid

A smart grid is an electricity network, which deals with electronic power conditioning and control of production, transmission, and distribution of electrical power by employing digital communication technologies to monitor and manage local changes in electricity usage. In the traditional power grid, energy consumers remain oblivious to their power consumption patterns, resulting in wasted energy as well as money. This issue is severely pronounced in the developing countries where there is a huge gap between demand and supply, resulting in frequent power outages and load‐shedding. For electrical energy savings, the smart grid employs demand side management (DSM), which refers to adaptation in consumer's demand for energy through various approaches such as financial incentives and awareness. The DSM in future smart grid must exploit automated energy management systems (EMS) built upon the state‐of‐the‐art technologies such as the internet of things (IoT) and cloud and/or fog computing. In this paper, we present the architecture framework, design, and implementation of an IoT and cloud computing‐based EMS, which generates load profile of consumer to be accessed remotely by utility company or by the consumer. The consumers' load profiles enable utility companies to regulate and disseminate their incentives and incite the consumers to adapt their energy consumption. Our designed EMS is implemented on a Project Circuit Board (PCB) to be easily installed at the consumer premises where it performs the following tasks: (a) monitors energy consumption of electrical appliances by means of our designed current and voltage sensors, (b) uploads sensed data to Google Firebase cloud over many‐to‐many IoT communication protocol Message Queuing Telemetry Transport (MQTT) where consumer's load profile is generated, which can be accessed via a web portal. These load profiles serve as input for implementing the various DSM approaches. Our results demonstrate generated load profiles of consumer load in terms of current, voltage, energy, and power accessible via a web portal.     

Scope and Limitations of the Intermolecular Furan‐Yne Cyclization

Different types of alkynes were reacted with 2,5‐disubstituted furans in order to evaluate the scope of the intermolecular furan‐yne reaction. With ethynyl aryl ethers as starting materials, 2‐phenoxy phenols were accessible in moderate to good yields. A different reaction mode was observed for alkynes bearing electron‐withdrawing substituents. For these starting materials a cis‐selective hydroarylation took place in an anti‐Markovnikov fashion in excellent yields. 1,2‐Diynes turned out to be suitable starting materials as well. Due to the second alkynyl moiety, after an initial phenol synthesis, a subsequent hydro‐alkoxylation by the newly formed phenolic oxygen gives access to benzofurans in a tandem process.

     

Laser Ablation Process Competency to Fabricate Microchannels in Titanium Alloy

Laser ablation is one of the competent machining processes to fabricate microfeatures in variety of engineering materials. This study has been progressed to evaluate the process capability of generating microchannels of various sizes (50 × 50 µm, 100 × 100 µm, 200 × 100 µm, and 1000 × 500 µm) in titanium alloy (Ti6Al4V) using Nd:YAG laser. Channel's top width, bottom width, depth, and taperness are examined as the four process responses against three laser based parameters to the naming of laser intensity, repetition rate, and scan speed. All the geometrical dimensions are measured through photographic snapshots of SEM of each fabricated channel. The results reveal that the selection of channel size is critical to achieve the desired machining geometries. Wider sized channels (such as 200 × 100 and 500 × 1000 µm) are experienced as more flexible to be generated than narrower sized channels (50 × 50 and 100 × 100 µm). The precise parametric combination is the key to realize more tight dimensional enormities with respect to the targeted machining elements. The most appropriate parametric combinations that can generate the respectable results are explored and applied for machining of different channel sizes.     

Mechanical stability and magnetic properties of austenite

Austenitic alloys have been produced by additional alloying in maraging steel grade 18 Ni at 2400 MPa. The concentration of Mo, Ni and Co was increased individually until the martensite start temperature M _s, was suppressed below ambient value. Charpy impact strength, tensile strength and magnetic properties were determined. The impact strength in the annealed condition ranged between 260 to 294 J. In alloys where martensitic transformation occurred following quenching in liquid nitrogen, the impact strength dropped appreciably and was found to be in the range 120–216 J. The tensile strengths of the austenite and martensite phases ranged between 680 to 890 and 1030 to 1100 MPa, respectively. It was observed that the austenite phase transformed to martensite in the region that under went plastic deformation during Charpy and tensile testing. The degree of transformation incorporated, varied as a function of composition. The magnetic properties of the austenite phases were typical of a very weak magnetic material. The coercive field and saturation magnetization values were in the range 1034–2387 Am^–1 and 1.6–2.9 T, respectively. In contrast to the general observation, the austenite phase containing high Co exhibited ferromagnetic behaviour. The coercive field and saturation magnetization of ferromagnetic austenite was 1034 Am^–1 and 11 T, respectively.     

Study of inclusions in a failed aero-engine component

The cause of the fatigue failure in the retaining ring of the compressor region of an aero-engine turbine was found to be the presence of a high concentration of nonmetallic inclusions. The results of chemical analysis were used to estimate the phases present. The most frequently observed inclusions were spinel solid solutions of the type MO · N₂O₃, where M=Fe, Mn, or Mg and N=Cr or Al. The detrimental inclusions were corundum, calcium aluminates, cristobalite, and silicates. The most detrimental phases were traced on the surfaces of the specimens fractured using impact loading; the comparison is being made with the polished surfaces and the tensile specimen fracture surfaces. The inclusions in the failed retaining ring were compared with the ones in a similar component obtained from a used engine. In the case of the latter, a large number of fine and elongated (Mn, Cr, Fe)S inclusions were present along with spinels. The nondeformable, rigid oxide particles are considered more undesirable than the sulfides as far as fatigue life of the component is concerned. It has been reported that the presence of sulfides may eliminate the stresses due to oxides.     

Corrosion properties of inconel 617 alloy after heat treatment at elevated temperature

Inconel alloys find wide application in industry as high-temperature resistance materials. In the present study, refurbishment of the Inconel 617 alloy after 37,000 h of operation in the field is carried out through the heat-treatment process. The electrochemical response of the heat-treated alloy is determined through potentiodynamic testing of the surfaces. The heat-treatment process is carried out at 1175 °C for 1 and 2 h in an air free furnace. The corrosion rate is estimated from TAFEL and polarization measurements. The surface morphology after the electrochemical tests is studied using scanning electron microscopy (SEM), while the material characterization at the surface is carried out using energy disperse spectroscopy (EDS). It is found that the corrosion resistance improves considerably for the workpieces subjected to 1 h heat treatment. The depletion of Cr and Mo at grain boundaries results in excessive pitting in this region. Moreover, enrichment of Cr at the surface after 1 h heat treatment reduces the corrosion current.     

Synthesis of allenyl ketones and their palladium-catalyzed cycloisomerization/dimerization: approaching the limits

The preparation of several new allenyl ketones 1a – j and 1o – q is reported. In the case of allenyl ketones with nucleophilic groups in the side-chain like 1k – m , the material polymerized during the purification procedure; with the dialkyl thioether 1n the product of a Pummerer isomerization, the acetoxymethyl alkyl thioether, 11 was formed. Depending on the route to 1 sometimes either the acetate adducts 8 and the 1-propynyl ketones 9 or the dipropargyl and propargyl allenyl carbinol 14 and 15 were observed as side-products. Good yields of the sensitive aryl γ-halogen- allenyl ketones 23a and 23b were obtained by a new synthetic route, on the other hand the aryl γ-silylallenyl ketone 23c was readily desilylated. Subjecting the new allenyl ketones to the PdCl₂(MeCN)₂ catalyst provided the 2-substituted furans 2 and the 2,4-disubstituted furans 3 in most cases. The yields and ratios of these products strongly depended on the nature of the groups being present. With the aryl thioether and the γ-halogen allenyl ketones the palladium-catalyzed reaction failed. Detailed structural information about the new products was provided by the X-ray structure analyses of the p-acetamidophenyl propargyl carbinol 6g and the 2-aryl-4-(1-methyl-3-aryl-3-oxo-propen-1-yl furan 3h .