Lump Formation Research Articles

Morphology and BET surface area of phosphoric acid stabilized tropical soils

It has been well established that the treatment of natural soil with chemical additives will gradually affect the size, shape, and arrangement of soil particles. Furthermore, the degree of improvement is dependent on the quantity and the pattern of new formed products deposited on and around the clay particles. In this paper, the time-dependent changes induced in the morphology and the surface area of phosphoric acid treated kaolinitic soils were studied using field emission scanning electron microscopy (FESEM) and Brunauer, Emmett and Teller (BET) surface area analysis method, respectively. Unconfined compressive strength test as an index of soil's improvement was also performed on cured samples. The results indicated that with the progression of curing time, the vigorous action of acid had transformed the soil structure into a more weathered composition consisting of sharper edged particles. Furthermore, at 8months curing period, the formations of white cementitious compounds in form of white lumps was evident. Based on the N2-BET results, it was found that the presence of iron oxides as part of laterite clay's secondary constituents (micro-aggregates), contributed to obtaining higher surface area values. These oxides were also believed to be the main cause of strength development at the early stages of curing.

The dissolution behavior of individual powder particles

The formation of lumps is a common problem during powder reconstitution in food industry. If more knowledge regarding the phenomena controlling the process could be obtained, the process of industrial powder recombination could be optimized. This demands investigation of the process at three different levels: the scale of individual powder particles, the scale of powder beds, and the scale of industrial recombination. If knowledge from all three scales could be combined, a model of the entire process could be constructed. In this study, we present a new flow-cell-based method for investigating the dissolution rate of individual powder particles in controlled liquid flow. The flow cell allows for alteration of the flow velocity and only subjects the investigated powder particles to mild stress before the analysis. The dissolution process in the cell is recorded, and data are obtained by image analysis. Sodium caseinate has been used as a model substance in these experiments. The results show that the particle dissolution rate is a function of the flow velocity of the liquid, and the results correspond to earlier established methods. The investigation of individual particles shows a variation in dissolution rate between particles resulting from the diverse particle morphology from an industrial batch of powder. The results indicate that the dissolution interface concentration of dissolving sodium caseinate particles corresponds well to the overlap concentration of the specie.

In vivo synergetic effect of in situ sclerotherapy and transient embolotherapy designed for fast-flow vascular malformation treatments with the aid of injectable hydrogel.

Fast-flow vascular malformations are very difficult to treat by the currently available drug delivery systems due to the particular obstacles associated with rapid blood flow. The goal of the present study is to address such a challenge through a novel chemotherapy approach with the aid of injectable hydrogel. Specifically, a pingyangmycin (PYM)/PECE hydrogel is purposely designed with a programmed synergetic therapy mechanism involving the transient embolotherapy of hydrogel and in situ chemotherapy induced by the locally released drug in a sustained manner. This formulation remained mobile at room temperature whereas rapidly undergoing in vivo sol-gel transition upon injection into the body. The sustained release characteristic of PYM/PECE formulation was revealed both in vitro and in vivo. All the pharmacokinetic characteristics were highly improved including the Tmax, Cmax, t1/2β and AUC(0-t). The exceptional efficacy of PYM/PECE formulation was validated by rapid vascular occlusion in rabbit's fast-flow central auricular arteries whereas respective PYM and PECE treatment failed. The most remarkable features included the precise control over the occlusion site and the irreversible formation of vessel-isolated cell-rich lumps that was believed to benefit the occlusion formation. Intravascular PYM/PECE administration induced neither toxic responses nor histopathological changes in rabbits' major organs. The hydrogel matrix could be completely absorbed in vivo. The present study highlighted the great promise of our design as a safe and extremely effective modality in the treatment of fast-flow vascular malformations.

Commentary on the myths of Peyronie's disease.

Peyronie’s disease refers to an acquired curvature, narrowing or shortening of the penis. Prevalence rates of 0.4-20% have been published (1). Development of Peyronie’s disease is likely related to minor injury to the tunica albuginea, septum or intracavernous struts. In some men, the resulting inflammation is trapped between layers of the collagen bundles and becomes progressive. This leads to an inflammatory mass (lump) formation in the early stage. Continuing inflammation produces profibrotic cytokines such as transforming growth factor beta and deposition of large amount of collagen fibers. The inflammation can also produce metalloproteinases that break the elastic fibers. The irregularly compacted collagen fibers and disrupted elastic fibers create an inelastic “plaque,” the “incurable” component of Peyronie’s disease.

On the mechanism of material removal by fixed abrasive lapping of various glass substrates

Glass ceramics are one of the important materials for optoelectronic devices. Fixed abrasive, double-sided lapping parameters (time, pressure, and platen speed) were optimized using borofloat, BK7 and quartz substrates. Lapping of borofloat, BK7 and quartz substrates were performed at optimized conditions. The removal rate was found to be highest in the case of borofloat, followed by quartz and BK7. The removal rate trend could not be explained based on the hardness of the material because quartz shows higher removal rate in spite of its higher hardness when compared to the BK7 substrate. The glass substrate forms a hydrated layer when it is exposed to an aqueous environment, and that depends on the composition of the substrate. The hardness of the material decreases significantly in the aqueous environment due to the formation of a hydration layer. The formation of a hydration layer is thought to facilitate faster and easier penetration of diamond abrasive into the substrate. Penetration then results in brittle fracture and the formation of lumps of debris.

Quality by design for wet granulation in pharmaceutical processing: Assessing models for a priori design and scaling

Abstract The effective implementation of Quality by Design (QbD) for wet granulation requires quantitative models for design and scaling of granulators. This paper reviews that current state of the art of granulation modeling, especially with respect to QbD in the pharmaceutical industry. Our thesis is that the state of the art use of high shear wet granulation models for QbD should be at the intermediate level between the extremes of data-driven empirical models and first principles models, i.e., regime-based models. These models have a sound mechanistic basis and can be used for both formulation design and process scaling. Although not fully predictive, regime map approaches are a significant advancement over a typical design of experiments approach, where little is known about the process. In addition, regime maps are particularly useful for process scale-up/down. This review focuses on the status of wet granulation regime maps and critically assesses their applicability to real, rather than model formulations. The approach is illustrated by two case studies. The first case study evaluates the effect of changing the properties of one excipient, lactose, on formulation behavior. Changing lactose size distribution leads to substantial changes in both the formulation drop penetration time and dynamic yield stress, which can lead to changes in operating regime. A size measurement technique that accurately measures the fine end of the distribution is necessary to predict the effect of changing the lactose size distribution. The second case study uses the regime map approach to propose a design space and scaling rules for a high drug load formulation, and successfully validate the scaling rules for scaling from a 10 l to a 75 l granulation. This case study emphasizes the importance of spray distribution to avoid operation in the mechanical dispersion regime and subsequent lump formation as a granulation is scaled up.

Long-term Complications from Breast Augmentation by Injected Polyacrylamide Hydrogel

Long-term Complications from Breast Augmentation by Injected Polyacrylamide Hydrogel

Histo-architectural alterations induced by Euclinostomum heterostomum (metacercariae) infected liver of Channa punctata (Bloch)

Present investigation was carried out to study the effect of digenetic trematode, Euclinostomum heretostomum on the histo-architecture of liver of Channa punctata. In case of mild infection, the metacercariae were found attached to the external surface of hepatic tissue. While in case of acute or chronic infection, the encysted metacercariae of Euclinostomum heterostomum were found deeply embedded in the entire hepatic tissue due to which liver appeared thin, compressed and pale with yellowish- black nodules of encysted metacercariae. A space occupying cavity is created by the metacercarial cysts due to which tissue appeared in the form of lumps. Histo-architectural alterations induced by parasite included degeneration, compression and loosening of hepatic tissue with enucleated and deshaped hepatocytes.

Evaluating conservative treatment for acute appendicitis with lump formation

Background:Interval appendectomy after acute appendicitis with lump formation (phlegmon) remains controversial. We conducted this study to determine the risk of recurrent appendicitis following initial non-operative treatment for appendicitis, and evaluate factors associated with recurrence. Secondarily, we evaluate the efficacy of interval appendectomy versus no appendectomy.Materials and Methods:Patients who received conservative treatment for appendicitis with lump formation were prospectively studied from June 2006 to June 2008. These patients were followed for recurrence of appendicitis.Results:Of 763 patients with acute appendicitis some 220 patients had lump formation (28.8%). Median age was 28 years. Conservative treatment was successful in 213 (96.8%) patients. The rate of recurrence was 13.1%, all occurring within six months after the index admission. Mean follow-up was 26±18 months.Conclusion:Conservative treatment of appendicitis with lump formation is efficient and the recurrence rate is low. Routine interval appendectomy after initial conservative treatment for lump formation is not a cost-effective intervention and not recommended.

Formation of superdense dark matter lumps at the radiation-dominated cosmological stage

We study the process of superdense dark matter clump (DMC) formation at the radiation-dominated stage of the Universe. High-magnitude density perturbations that lead to DMC formation can be peaks in the inflationary perturbation spectrum or closed loops of cosmic strings. A model with superdense DMCs provides new opportunities for annihilation of particles having small annihilation cross-sections. Superdense DMCs can be detected by their tidal effect on gravitational wave detectors.

Nutrient and Anti-Nutrient Content of Soy-Enriched Tapioca

Tapioca is a cassava-based food product made in the form of irregular lumps of partly gelatinized starch grits. Tapioca was enriched with varying proportions of soybean flour (0, 85% - 15%, 75% - 25%, 50% - 50%) to produce Soy-tapioca (ST). Nutrient and anti-nutrient composition of ST were determined by standard methods, while sensory evaluation was also carried out. Results showed significant increase in protein, fat and mineral contents of tapioca as the level of soy-substitution increased. There was a decrease in the cyanogenic potential and an increase in the level of trypsin inhibitor as soy-substitution increased. Tannin, phytic acid and oxalate contents of the soy-tapioca samples were below minimum levels of safety. ST (50% - 50%) was more nutrient dense than the other products, but ST (85% - 15%) was more accepted in terms of colour, taste and texture. ST suggests a safe, nutritious and acceptable food product that can enhance food and nutrition security among cassava consuming populations.

Crucial factors for catalyst aggregation and deactivation on Co/Al 2O 3 in a slurry-phase Fischer–Tropsch synthesis

The different behaviors for catalyst deactivation by forming aggregated catalyst lumps were investigated on the phosphorous-modified Co/P–Al 2O 3 and the unmodified Co/Al 2O 3 Fischer–Tropsch synthesis (FTS) catalysts in a slurry-phase continuous stirred tank reactor. The lower catalytic activity at steady-state with a fast deactivation rate was observed on the phosphorous-unmodified Co/Al 2O 3 catalyst due to the facile formation of aggregated catalyst lump with a high hydrophilic property of support and a significant hydrocarbon deposition on catalyst surface. The amount of adsorbed water and the deposited hydrocarbons are strongly related with aggregated catalyst lump formation. The adsorbed water could possibly transform the local γ-Al 2O 3 surface to pseudo-boehmite (Bronsted acidic Al 2OH sites) material which is characterized as a low attrition resistance and accelerates the formation of fine powders during FTS reaction. The formed fine powder during FTS reaction could be easily aggregated and it is resulted in catalyst deactivation due to the difficult intraparticular diffusion of reactants. The possible mechanisms of phase transformation of γ-Al 2O 3 to pseudo-boehmite and formation of aggregated catalyst lump were suggested by measuring the deposited hydrocarbons and the concentration of adsorbed water on catalyst surface with the help of the characterizations such as X-ray photoelectron spectroscopy, temperature-programmed surface reaction, diffuse reflectance infrared Fourier transform and water-sorption method.

Oscillating non-linear large-scale structures in growing neutrino quintessence

Growing Neutrino quintessence describes a form of dynamical dark energy that could explain why dark energy dominates the universe only in recent cosmological times. This scenario predicts the formation of large scale neutrino lumps which could allow for observational tests. We perform for the first time N-body simulations of the nonlinear growth of structures for cold dark matter and neutrino fluids in the context of Growing Neutrino cosmologies. Our analysis shows a pulsation - increase and subsequent decrease - of the neutrino density contrast. This could lead to interesting observational signatures, as an enhanced bulk flow in a situation where the dark matter density contrast only differs very mildly from the standard LCDM scenario. We also determine for the first time the statistical distribution of neutrino lumps as a function of mass at different redshifts. Such determination provides an essential ingredient for a realistic estimate of the observational signatures of Growing Neutrino cosmologies. Due to a breakdown of the non-relativistic Newtonian approximation our results are limited to redshifts z > 1.

FLOW AND FUNCTIONAL CHARACTERIZATION OF CORNSTARCH POWDER IN THE PRESENCE OF WATER AND PREGELATINIZED STARCH

ABSTRACTA model system comprising cornstarch has been agglomerated in the presence of binders like water and pregelatinized starch (PGS). Moisture and PGS contents have been varied between 12.3 and 20.1% and 0 and 6%, respectively. The physical characteristics of powder that have been determined include loose bulk density, wetting time and sinking time. A powder flow analyzer has been employed to determine flow characteristics like maximum force and energy for compression and decompression. An increase in moisture content and/or PGS increases average particle size and loose bulk density of agglomerates. The wet agglomerates show improved wetting and sinking times compared to dried agglomerates. Like wetting time, sinking time also decreases with an increase in moisture content meaning that these two indices behave in a similar manner. The functional properties like wetting and sinking times of powders at 18.5% moisture made with PGS are instant and only take less than 5 s.PRACTICAL APPLICATIONProcessed powdered foods frequently undergo the process of rehydration with a solvent system such as water or milk. Hence, the powder needs to be wetted quickly and thoroughly, sinking into the liquid rather than floating at the liquid surface and disperse/dissolve preferably without any lump formation. The importance of wetting time lies in the development and quality control of several food powders like milk powder, instant tea, coffee and mixes that are claimed to have instant properties. The generated data and findings, although developed on a model system, can be extrapolated to other food systems for developing new products for convenience to consumers.

Shelf life prediction of aluminum foil laminated polyethylene packed vacuum dried coconut milk powder

Shelf life of vacuum dried coconut milk powder packed in aluminum foil laminated polyethylene packages was predicted using developed mathematical models based on two limiting criteria viz., onset of caking and lipid oxidation. Accelerated storage studies for coconut milk powder packed in aluminium foil laminated polyethylene pouches were conducted at 90±1% relative humidity and 38±2°C temperature. Threshold value for the shelf life prediction based on moisture migration was taken as the critical moisture content at which lump formation was observed. Shelf life prediction based on lipid oxidation involved establishing relationships between rate of oxygen absorption, package oxygen concentration, volume of O2 absorbed, peroxide value of the powder and storage time. A peroxide value of 10mEq. of O2 per kg fat was considered as the threshold limit for oxidative rancidity. A good fit between experimental and predicted data with relative deviation percent below 10% was observed during storage studies.

Peptide reactivity of aromatic amine hair dye precursors correlates with the impact of oxidation and N-acetylation for skin sensitization

The antioxidant activity and food protection effect of bioactive polypeptides from bovine hair were investigated. In various in vitro tests, polypeptides showed a strong reducing power and a remarkable antioxidant capability to scavenge free radicals (ABTS, superoxide and hydroxyl radicals). Moreover, polypeptides also exhibited a significant food protection effect to inhibit the oxidation of edible oil by controlling the peroxide value (POV). Furthermore, by using gel filtration chromatography (GFC), high performance size exclusion chromatography (HPSEC), amino acid analysis and atomic force microscopy (AFM), an antioxidant polypeptide (APB) was purified and characterized with a molecular weight of 18.7 KDa in the form of spherical lumps, which was composed of 17 kinds of amino acids and contained sulfydryl group. Our results suggested that the antioxidant polypeptide from bovine hair could be a new potential source for preparing natural antioxidant applied in oil or oil-rich food.

Comparison of Pulse Electric Field and Thermal Processing on Mass Transfer in Sugar Extraction from Sugar Beet

اثر میدان الکتریکی پالسی قوی بر فرآیند انتقال جرم از خلال چغندر با ضخامت های متفاوت در مقایسه با تیمار حرارت مورد بررسی قرار گرفت . برای این منظور، میدان الکتریکی قوی (با قدرت kV3، µF 8 با 20 پالس) بر دو نوع خلال ضخیم با ابعاد 5/0 ± 3 میلی متر عرض و خلال نازک 3/0 ± 2 عرض هر دو دارای 5-3 سانتی متر طول اعمال و با نمونه های تیمار شده توسط حرارت C°80 به مدت ثابت 15 دقیقه مقایسه گردیدند. نمونه های شاهد و تیمار شده توسط پرس آزمایشگاهی در سه مرحله و هربار به میزان 20بار (2 مگاپاسکال) فشرده و میزان بریکس ، هدایت الکتریکی شربت حاصل به عنوان شاخص های انتقال جرم ، راندمان شربت و سرعت خشک شدن تفاله حاصل از نمونه ها نیز اندازه‌گیری شدند. نتایج پس از تجزیه و تحلیل آماری حاکی از افزایش انتقال جرم بیش از دو برابر در نمونه های تیمار شده با میدان الکتریکی به ویژه در خلال نازک و نیز افزایش راندمان بالاتر شربت نسبت به فرآیند حرارتی بود . بیشترین میزان مواد جامد محلول در اولین مرحله پرس به دست آمد. هم چنین سرعت خشک شدن تفاله در نمونه های تیمار شده توسط میدان الکتریکی به دلیل حفظ شکل فیزیکی خلال ها ، افزایش روزنه های ایجاد شده در بافت و سلولهای چغندر در مقایسه با نمونه های تیمار شده توسط حرارت به دلیل از هم گسیختگی سلولها و ایجاد کلوخه و ممانعت از خروج رطوبت افزایش قابل ملاحظه ای نشان دادند. واژه های کلیدی: میدانهای الکتریکی پالسی، انتقال جرم، چغندر قند، بریکس، هدایت الکتریکی

Study of Pellets and Lumps as Raw Materials in Silicon Production from Quartz and Silicon Carbide

The use of high-purity carbon and quartz raw materials reduces the need for comprehensive refining steps after the silicon has been produced carbothermically in the electric reduction furnace. The current work aims at comparing the reaction mechanisms and kinetics occurring in the inner part of the reduction furnace when pellets or lumpy charge is used, as well as the effect of the raw material mix. Laboratory-scale carbothermic reduction experiments have been carried out in an induction furnace. High-purity silicon carbide and two different high-purity hydrothermal quartzes were charged as raw materials at different molar ratios. The charge was in the form of lumps (size, 2–5 mm) or as powder (size, 10–20 μm), mixed and agglomerated as pellets (size, 1–3 mm) and reacted at 2273 K (2000 °C). The thermal properties of the quartzes were measured also by heating a small piece of quartz in CO atmosphere. The investigated quartzes have different reactivity in reducing atmosphere. The carbothermal reduction experiments show differences in the reacted charge between pellets and lumps as charge material. Solid–gas reactions take place from the inside of the pellets porosity, whereas reactions in lumps occur topochemically. Silicon in pellets is produced mainly in the rim zone. Larger volumes of silicon have been found when using lumpy charge. More SiO is produced when using pellets than for lumpy SiO2 for the same molar ratio and heating conditions. The two SiC polytypes used in the carbothermal reduction experiments as carbon reductants presented different reactivity.

Cosmological Classicalization: Maintaining Unitarity under Relevant Deformations of the Einstein-Hilbert Action

Generic relevant deformations of Einstein's gravity theory contain additional degrees of freedom that have a multifaceted stabilization dynamics on curved spacetimes. We show that these relevant degrees of freedom are self-protected against unitarity violations by the formation of classical field lumps that eventually merge to a new background geometry. The transition is heralded by the massive decay of the original vacuum and evolves through a strong coupling regime. This process fits in the recently proposed classicalization mechanism and extends it further to free field dynamics on curved backgrounds.

Processing of surface-treated boron carbide-reinforced aluminum matrix composites by liquid–metal stir-casting technique

Boron carbide is one of the potential neutron-shielding materials and its use can be maximized for structural shielding application by dispersing it into metal matrixes such as aluminum. Dispersion of B4C and its interfacial stability is a major issue during its processing. This investigation is on the synthesis of B4C-reinforced 6061 aluminum matrix composite by liquid–metal stir-casting technique under optimized conditions after solving the issues related to the processing, and evaluation of the structural, mechanical, and interfacial characteristics. During processing of composites, pretreatment of B4C particles is necessary to improve its dispersion. However, higher preheating temperatures above 300°C lead to particle agglomeration in the matrix due to the formation of B2O3 phase during preheating. B2O3 is formed due to the surface oxidation of B4C particles above 300°C and this glassy phase leads to particle sintering and lump formation. Incorporation of particles preheated at 250°C has shown uniform distribution of particles in the composite. Interfacial characterization of the composite and the extracted B4C particles from the matrix has shown the presence of interfacial reaction products such as AlB2, Al3BC, AlB12, and AlB10.