Review: Investigation of Partially Pre-mixed Charge Ignitions (PPCI) Engine Mode

This paper embraces the key points of unpolluted internally combusted engine emissions. Core objective is focused on the recent effort to improve compression ignition(CI) and spark ignition(SI) engine to have fuel-efficient and minimized pollutant emissions. There are many advanced internal combustion engines to overcome the challenges of conventional compression ignition engines of the high level of particulate matter(PM) and oxides of nitrogen emission. One of the latest options on which many ...     

Estimating probabilistic fatigue of Nitinol with scarce samples

Current work estimates probabilistic fatigue life efficiently with scarce samples. The underlying idea of the estimation is to approximate the cumulative distribution function of the fatigue life in a transformed space using a third order polynomial subject to monotonicity constraint. The variations associated with the estimated quantiles are quantified using bootstrap. The proposed approach is validated on a data obtained from literature. It is observed that the life quantiles with reasonable accuracy can be estimated even with 10 samples. Finally, the probabilistic fatigue of Nitinol in austenitic condition is obtained with limited experiments.     

Detection of the residues of nineteen pesticides in fresh vegetable samples using gas chromatography–mass spectrometry

In this study, we investigated the presence of 19 different agricultural pesticides in 210 samples of eight types of domestic vegetables collected from several vegetable-growing regions in Bangladesh. A multiresidue method was developed to detect the pesticide levels in the collected samples using gas chromatography with mass spectrophotometry (GC–MS). Pesticide residues were detected in 51.30% of the total samples, and among the positive samples, 38.89% contained levels above the maximum residue levels (MRLs). The most frequently detected pesticides were chlorpyrifos (34) followed by carbofuran (17), diazinon (16), carbaryl (14), malathion (11), endosulfan (8), cypermethrin (7) and dimethoate (6). Some (10.47%) of the samples contained multiple residues. It is concluded that the continuous monitoring and strict regulation of pesticide use on food crops, especially vegetables, are necessary.     

Effects of monovalent and divalent metal sulphates on consistency and compaction of lime-stabilised kaolinite

The factors influencing the durability of compacted lime-stabilised clay soils depend in part on the short-term material properties that emanate from the immediate changes that occur (within a few hours) during the initial part of the stabilisation process. The long-term properties take a much longer period to develop and small changes are still occurring after several years. In both cases, the genesis of the properties may be directly linked to the properties of the parent soil and the cationic process that takes place as soon as the mix materials are in contact with water. Thus, the significance of the constitution of the parent material and the factors influencing the cationic exchange process cannot be overemphasised. Both these factors are affected by the presence of sulphates in the soil. This paper shows how the commonly occurring monovalent metal sulphates of sodium and potassium, and the divalent ones of calcium (gypsum) and magnesium, affect the consistency and dynamic compaction properties of an industrial kaolinitic clay soil of high purity, to which sulphates have been artificially introduced. The results clearly illustrate that the effects of the presence of sulphate depend strongly on the sulphate cation type. Some cations (Ca²⁺ and Mg²⁺) enhance the effects of lime addition while others have the tendency to reverse these effects (Na⁺ and K⁺).     

Effect of manifold injection of hydrogen gas in producer gas and neem biodiesel fueled CRDI dual fuel engine

The high flammability of hydrogen gas gives it a steady flow without throttling in engines while operating. Such engines also include different induction/injection methods. Hydrogen fuels are encouraging fuel for applications of diesel engines in dual fuel mode operation. Engines operating with dual fuel can replace pilot injection of liquid fuel with gaseous fuels, significantly being eco-friendly. Lower particulate matter (PM) and nitrogen oxides (NO_x) emissions are the significant advantages of operating with dual fuel.Consequently, fuels used in the present work are renewable and can generate power for different applications. Hydrogen being gaseous fuel acts as an alternative and shows fascinating use along with diesel to operate the engines with lower emissions. Such engines can also be operated either by injection or induction on compression of gaseous fuels for combustion by initiating with the pilot amount of biodiesel. Present work highlights the experimental investigation conducted on dual fuel mode operation of diesel engine using Neem Oil Methyl Ester (NeOME) and producer gas with enriched hydrogen gas combination. Experiments were performed at four different manifold hydrogen gas injection timings of TDC, 5°aTDC, 10°aTDC and 15°aTDC and three injection durations of 30°CA, 60°CA, and 90°CA. Compared to baseline operation, improvement in engine performance was evaluated in combustion and its emission characteristics. Current experimental investigations revealed that the 10°aTDC hydrogen manifold injection with 60°CA injection duration showed better performance. The BTE of diesel + PG and NeOME + PG operation was found to be 28% and 23%, respectively, and the emissions level were reduced to 25.4%, 14.6%, 54.6%, and 26.8% for CO, HC, smoke, and NO_x, respectively.     

Effect of pressure on structural and elastic properties of alkaline-earth oxide CaO

We have performed ab initio calculations using a plane wave pseudopotential method to investigate the phase transition of alkaline-earth oxide CaO from NaCl (B1) to CsCl (B2) type structure. The elastic constants for this material have been determined in the pressure range 0–140 GPa. Also, the effect of hydrostatic pressure on the propagation elastic waves has been studied. The specific elastic constants, bulk modulus and wave velocities that we calculated for both B1 and B2 type structures are in good agreement with the available experiment data.     

Biopolymer-assisted green synthesis and characterization of calcium hydroxide nanoparticles

The use of biopolymers in the synthesis of different nanostructures can be a cost effective and eco-friendly approach. In the present study, a facile and “green” sol–gel method was employed for preparing calcium hydroxide nanoparticles (Ca(OH)₂-NPs) in gelatin matrix as a bio-template. Prepared nanoparticles were characterized by different instruments such as powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FESEM), and Fourier transform infrared spectroscopy (FTIR). The PXRD analysis revealed hexagonal Ca(OH)₂-NPs with preferential orientation in (101) reflection plane. They are hexagonal in shape with a mean particle size of approximately 42 nm in thickness. The synthesized Ca(OH)₂-NPs using gelatin were found to be comparable to those obtained from conventional methods using hazardous capping/stabilizing polymeric agents or surfactants and this route can be an excellent alternative for the synthesis of Ca(OH)₂-NPs using biomaterials.     

Nd3+-sensitized upconversion nanoparticle coated with antimony shell for bioimaging and photothermal therapy in vitro using single laser irradiation

Combining treatment and diagnosis, called theranostics, which is achieved within single nanoparticle is an ultimate goal of many studies. Herein, we developed a new nanotheranostic agent ? Nd³⁺-sensitized upconversion nanoparticles core for dual modal imaging (i.e., upconversion luminescence imaging and magnetic resonance imaging) and antimony nanoshell for photothermal therapy (PTT). The core-shell-shell upconversion nanoparticles (NaYF₄:Yb,Er@NaYF₄:Yb,Nd@NaGdF₄:Nd, named as UCNP) were firstly synthesized using thermal decomposition method and then were coated by antimony shell over the surface of UCNP using simple cost and time effective new method. Furthermore, the surface of UCNP@Sb nanostructures was modified with DSPE-PEG in order to enhance the water solubility and biocompatibility. The final nanotheranostic agent, named as UCNP@Sb-PEG, exhibits very low toxicity, good biocompatibility, very good photothermal therapeutic effect, and efficient upconversion luminescence (UCL) imaging of HeLa cells under only one laser (808 nm) irradiation. The antimony shell is quenching the upconversion emission in pristine nanotheranostic agent, but interestingly, the UCL intensity of the agent recovers progressively under 808 nm laser irradiation due to light induced degradability of antimony shell. Besides, high longitudinal relaxivity (r₁) obtained from the experiment approves excellent potential of the nanotheranostic agent for T₁-weighted magnetic resonance imaging application.     

Recent achievements in the microbial synthesis of semiconductor metal sulfide nanoparticles

Taking the advantage of several species of microorganisms, different kinds of chalcogenide nanocrystals have been bio-fabricated in intra/extracellular modes with interesting specifications. However, the most extensive research among these semiconducting materials has been focused on metal sulfides. Generally, bacteria, fungi or other microorganisms convert dissolved sulfate ions into reduced sulfides using certain enzymes and under different conditions, and subsequently, the sulfide anions react with soluble metal cations to generate the insoluble metal sulfide precipitates. Recently, in addition to the biosynthesis procedure, the bio-produced nanomaterials have been examined for their applications as photo-catalysis materials, electrical devices, and antibacterial and antifungal agents. Therefore, the present review is an attempt to collect the available literatures published worldwide on the biosynthesis of semiconductor metal sulfide nanocrystals and concisely compare and evaluate the applied techniques and approaches with an insight into the practical use of their product.     

Sugarcane Bagasse ash substituent feldspar for the production of porcelain electrical insulators

Sugarcane bagasse ash (SCBA) industrial waste was used to partially substitute feldspar in the production of porcelain electrical insulators from a mixture of locally available Bombawuha clay (BC), Chancho sand (CS), and mixture of Wolkite (WF) and Arerti feldspar (AF) (50:50%). The raw materials were characterized for their chemical composition, mineralogy, thermal behavior, and plasticity. The porcelain electrical insulator formulations containing various proportions of SCBA (0 wt%, 10 wt%, 15 wt%, and 20 wt%) were fired at different firing temperatures of 1200 °C, 1250 °C, and 1300 °C for 2.5 h. The fired bodies were evaluated for water absorption, apparent porosity, bulk density, flexural strength, dielectric strength, and microstructure. The results showed that SCBA had 65.06% silica (SiO₂) and had higher alkaline and iron oxide (Fe₂O₃) contents than the natural feldspars. Bombawuha clay contained kaolinite as a major mineral with a middle range plasticity index (PI = 11.2%) and the met the required purity necessary for mullite phase formation. The feldspars had a low alkali content of sodium oxide plus potassium oxide (Na₂O + K₂O) of < 6 wt %. The prepared porcelain insulator containing 10% SCBA, 50% BC, 30% mixed feldspars, and 10% CS, and fired at 1250 °C for 2.5 h exhibited a water absorption of 0.35%, flexural strength of 42.50 MPa, and a dielectric strength of 6.59 kV/mm, which satisfies the obligatory properties for quality porcelain insulators. Further, the partial replacement of feldspar by SCBA up to 10 w% lowered the firing temperature by 50 °C.