Dirt Contamination Research Articles

Follicular Ameloblastoma of Maxillary: A Case Report

Introduction: Ameloblastoma is a benign odontogenic tumor that appears in the mandible and maxilla. Ameloblastoma has slow growth that takes several years for symptoms to appear, but ameloblastoma in the maxilla has a more aggressive clinical course compared to the mandible. The lack of initial symptoms leading to diagnosis at an advanced disease when the tumour has already extended beyond maxilla. The cancellous structure of the maxillary bone makes it easier for tumors to spread to the nasal cavity, paranasal sinuses, orbitals, parapharyngeal tissue and skull base. This article reports a case of resection of maxillary ameloblastoma. Case Report: A 63 year old female patient came with complaints of a lump on her right cheek since 2 years back that gradually increased in size. Since 2 months ago, pus and blood have been coming out of the lump. Extra oral examination revealed a well-defined mass with a solid and hard consistency, there were no ulcers or fistulas. Intraorally, a mass measuring 5x5x3cm was found in the region of teeth 12 to 15 which extended to the buccal-palatal area. History of allergies and weight loss was denied. Supporting examinations including panoramic radiography, PA chest radiography, CT-Scan, FNAB, and biopsy resulted in a diagnosis of ameloblastoma. Treatment was carried out by resection of the right maxillary tumor mass under general anesthesia. Discussion: In this case, the patient's clinical examination showed a hard and large palpable swelling in the right maxilla area which extended from the region of tooth 12 to tooth 15 which caused facial asymmetry and no tooth mobility was found. This hard and painless swelling takes about 2 years before the patient experiences symptoms of pus and blood discharge. The post-maxillectomy defect in this case was covered with an intraoral prosthesis in the form of a post-surgical obturator made of acrylic resin. The obturator functions to hold the surgical packing, and prevent food or dirt contamination in the defect area which can cause infection and slow healing. The use of a prosthesis also helps restore swallowing and speech function to the patient. Conlussion: In principle, the treatment for ameloblastoma is resection of the involved bone, as in this case the action taken is a maxillectomy. Maxillectomy can result in facial and oral cavity deformities characterised by facial disfigurement and alterations in oral functionality.Therefore, maxillary reconstruction is needed to treat maxillary defects after surgical procedures involving the loss of part or all of the maxilla.

Passive daytime radiative cooling coatings with renewable self-cleaning functions

Passive daytime radiative cooling (PDRC) technology is emerging as one of the most promising solutions to the global problem of spacing cooling, but its practical application is limited due to reduced cooling effectiveness caused by daily wear and tear, as well as dirt contamination. To tackle this problem, we report a novel strategy by introducing a renewable armor structure for prolonging the anti-fouling and cooling effectiveness properties of the PDRC coatings. The armor structure is designed by decorating fluorinated hollow glass microspheres (HGM) inside rigid resin composite matrices. The HGM serve triple purposes, including providing isolated cavities for enhanced solar reflectance, reinforcing the matrices to form robust armored structures, and increasing thermal emittance. When the coatings are worn, the HGM on the surface expose their concave cavities with numerous hydrophobic fragments, generating a highly rough surface that guarantee the superhydrophobic function. The coatings show a high sunlight reflectance (0.93) and thermal emittance (0.94) in the long-wave infrared window, leading to a cooling of 5 °C below ambient temperature under high solar flux (∼900 W/m2). When anti-fouling functions are reduced, they can be regenerated more than 100 cycles without compromising the PDRC function by simple wearing treatment. Furthermore, these coatings can be easily prepared using a one-pot spray method with low-cost materials, exhibit strong adhesion to a variety of substrates, and demonstrate exceptional environmental stability. Therefore, we anticipate their immediate application opportunities for spacing cooling.

Design of pliek-u dryer using Dafa-type solar energy

One of the food diversification strategies of coconut commodity is to process it into Pliek U. Pliek U is a typical food of the Province of Aceh, Indonesia, which in its processing stage requires a drying process. So far, Pliek U drying process is often conducted conventionally through direct drying (sun drying), so that Pliek U produced is susceptible to dust and other dirt contamination. This research aimed to design a Pliek U dryer using Dafa type solar energy. The Dafa type solar energy dryer used a turbine ventilator with a vertical axis wind turbine equipped with two solar collectors. This turbine had a simple shape and construction and was arranged like the letter S. While the two parts of the solar collector were used to collect energy from the sun directly. In the experiment, the blank test was carried out in the time range, namely from 10.20 am to 04.50 pm in sunny weather, with an interval of 30 minutes for each temperature data recording. The empty test results of the Dafa type solar energy dryer showed that the average shelf temperature was 44.21 °C, the collector temperature was 45.64 °C, and the ambient temperature was 31.14 °C. This initial test revealed that the performance ability of the tool was very effective in maintaining temperature during the drying process, so that further tests using materials for drying Pliek U may be carried out.

Durable self-cleaning nano-titanium dioxide superhydrophilic coating with anti-fog property

PurposeThis paper aims to design the nano-titanium dioxide (TiO2) coating system which has superhydrophilic property, self-cleaning mechanism and antifog property as well as strong adhesion on glass substrate.Design/methodology/approachTwo hydrophilic materials have been used such as TiO2 nanoparticles as fillers and hydrophilic copolymer, Pluronic F-127 by using simple sol–gel approach. The prepared solution was applied onto glass through dip- and spray-coating techniques and then left for drying at ambient temperature.FindingsThe nano-TiO2 superhydrophilic coating has achieved the water contact angle of 4.9° ± 0.5°. The superhydrophilic coating showed great self-cleaning effect against concentrated syrup and methylene blue where thin layer of water washes the dirt contaminants away. The nano-TiO2 coating exhibits great antifog performance that maintains high transparency of around 89% when the coated glass is placed above hot-fog vapor for 10 min. The fog droplets were condensed into water film which allowed the transmission of light through the glass. The strong adhesion of coated glass shows no total failure at scratch profile when impacted with scratch load of 500, 800 and 1,200 mN.Research limitations/implicationsFindings will be useful in the development of self-cleaning superhydrophilic coating that is applicable on building glass and photovoltaic panel.Practical implicationsThe developed nano-TiO2 coating is developed by the combination of hydrophilic organic copolymer–inorganic TiO2 network to achieve great superhydrophilic property, optimum self-cleaning ability and supreme antifog performance.Social implicationsThe findings will be useful for residents in building glass window where the application will reduce dust accumulation and keep the glass clean for longer period.Originality/valueThe synthesis of nano-TiO2 superhydrophilic coating which can be sprayed on large glass panel and cured at ambient temperature.

Hierarchically Superhydrophobic Stereo‐Complex Poly (Lactic Acid) Aerogel for Daytime Radiative Cooling

AbstractPassive radiative cooling technology provides a sustainable way of cooling by the combination of emitting heat to the cold universe and reflecting solar light without any energy input. However, the massive consumption of non‐degradable radiative cooling materials causes resource waste and environmental pollution. Meanwhile, the cooling efficiency can be easily affected by dirt contamination in outdoor environments. Here, by the combination of biomimetic hierarchical structure design and stereo‐complex crystals, a degradable and superhydrophobic (152°) stereo‐complex poly (lactic acid) aerogel with low thermal conductivity (37 mW m–1 K–1), high compression strength (0.1 MPa) and self‐cleaning ability via a simple water‐assisted thermally induced phase separation method is developed. The optimal aerogel has a high sunlight reflection (89%) and strong infrared emissivity (93%) that gets a temperature drop of 3.5 °C during the daytime and 5.8 °C during the nighttime. This aerogel opens an environmentally sustainable pathway to radiative cooling applications.

Milk quality improvement through the application of plantaricin IIA-1A5 as biopreservatives on fresh milk in dairy cow farm

Foods are better being consumed raw and fresh, however, fresh milk has different case. In fact, drinking fresh milk still became a debate until this day. Some claims said unprocessed fresh milk contains more nutrition compared with pasteurized milk, although milking process do not guarantee protection from bacteria and dirt contamination. One type of bacteriocin known is plantaricin IIA-1A5, this bacteriocin has role as natural biopreservative because it contains antimicrobial compound which expected to be able to damage and kill pathogenic bacteria such as S. aureus by inhibiting other bacteria growth with damaging its cell membranes. This study data analysis was conducted using randomized block design (RDB) with 3 repetitions. Treatment design consisted of control, plantaricin (11.02 mL), and penicillin (7.5 mL). Microbiological characteristics, physicochemical characteristics, and Lowry Protein Assay Method tests were carried out. The results showed that microbiological characteristics and physicochemical characteristics have met SNI Standards, namely 01-3951:1995, 7388:2009, and 3141.1:2011.

VLF Dielectric Response and HF Localized Dielectric Discharge Measurement for Rotating Machine Insulation Assessment

This paper represents the very low frequency (VLF) dielectric response and high frequency (HF) localized dielectric discharge measurement for rotating machine insulation assessment. The integral conditions of stator winding insulation, the so-called aging condition, were investigated by the dielectric response measuring technique. The polarization and depolarization currents in the VLF range from 0.0001 to 1 Hz were measured under an external step electric field. The local conditions of stator winding insulation, the so-called weak spot condition, were examined by the partial discharge (PD) measuring technique. The PD pulse currents were detected by a capacitive sensor in a wide-band range, where the bandwidth of the measuring system was set between 30 kHz and 30 MHz. The medium voltage rotating machine rated 6.6 kV and 240 to 2,270 kW under different service conditions, i.e., new stator winding, moisture contamination, dirt contamination as well as thermally and severely aged insulation, was studied. Besides, four case studies on measuring the PD in service rotating machines rated 11–15 kV, 7100 to 211,000 kW as well as the attenuation of the PD pulses were conducted and demonstrated. With several case studies, this paper introduces new dielectric parameters, the so-called charge ratio (QR) and charge difference gradient (QDG), to identify the dielectric mechanism occurring in the stator winding insulation caused by the polarization and conduction processes. It can be concluded that the proposed parameters are a valuable tool for assessing the aging condition. In the case of the PD measurement, it was found that the PD pulse is strongly attenuated in the slot section. This paper also introduces the combination of both the dielectric response and PD measurement results, which can be very useful for assessing a complete insulation condition in the rotating machine. Moreover, the criteria for insulation conditions are suggested in this paper to evaluate the integral and local conditions for the rotating machine insulation. The local discharge in the machine causes electromagnetic waves, which may get released from the non-perfect characteristics of the enclosure. This signal may interfere with the functioning of other nearby electronic devices, especially the communication equipment. Therefore, maintaining the excellent condition of the insulation system by the proposed technique detailed in this paper will support the highly effective operational efficiency of the communication system as well.

The pyriform egg of the Common Murre (Uria aalge) is more stable on sloping surfaces

The adaptive significance of avian egg shape is a long-standing problem in biology. For many years, it was widely believed that the pyriform shape of the Common Murre (Uria aalge) egg allowed it to either “spin like a top” or “roll in an arc,” thereby reducing its risk of rolling off the breeding ledge. There is no evidence in support of either mechanism. Two recent alternative hypotheses suggest that a pyriform egg confers mechanical strength and minimizes the risk of dirt contamination of the blunt end. We present a new hypothesis: that the Common Murre egg's pyriform shape confers stability on the breeding ledge, thus reducing the chance that it will begin to roll. We tested this hypothesis by measuring the stability of Common Murre and Razorbill (Alca torda) eggs of different shapes on slopes of 20°, 30°, and 40° above the horizontal. Common Murre eggs were more stable, and easier to stabilize, than the more elliptical Razorbill eggs. Within Common Murre eggs, more pyriform eggs were more stable. From a fitness perspective, the stability of the Common Murre egg on a slope seems likely to confer an advantage and thus may be a strong force of natural selection favoring the pyriform shape.

Eddy-covariance flux errors due to biases in gas concentration measurements: origins, quantification and correction

Abstract. Errors in gas concentration measurements by infrared gas analysers can occur during eddy-covariance campaigns, associated with actual or apparent instrumental drifts or biases due to thermal expansion, dirt contamination, aging of components or errors in field operations. If occurring on long timescales (hours to days), these errors are normally ignored during flux computation, under the assumption that errors in mean gas concentrations do not affect the estimation of turbulent fluctuations and, hence, of covariances. By analysing instrument theory of operation, and using numerical simulations and field data, we show that this is not the case for instruments with curvilinear calibrations; we further show that if not appropriately accounted for, concentration biases can lead to roughly proportional systematic flux errors, where the fractional errors in fluxes are about 30–40% the fractional errors in concentrations. We quantify these errors and characterize their dependency on main determinants. We then propose a correction procedure that largely – potentially completely – eliminates these errors. The correction, to be applied during flux computation, is based on knowledge of instrument calibration curves and on field or laboratory calibration data. Finally, we demonstrate the occurrence of such errors and validate the correction procedure by means of a field experiment, and accordingly provide recommendations for in situ operations.

Degradation of Recycled Polyethylene Film Materials Due to Contamination Encountered in the Products' Life Cycle

The recycling of polyethylene (PE) film is a straightforward process, provided the material that is being recycled has come from a clean source and is consistent in composition. Most waste film recovered for recycling has been subjected to a series of ‘life cycle factors’, e.g. comingling with wastes such as dirt, packaging tapes, and other plastic film products. Such contamination can degrade the material's physical properties and this article presents quantitative data on the effects of contaminants on PE films. Results suggest that dirt contamination can adversely affect the elasticity and melt viscosity of the polymer, but the contaminant does not interact directly with it and that polypropylene-based packaging tape is more suited to mechanical recycling than polyvinyl chloride or cellulose-based tapes.

Don't ban PVC: incinerate and recycle it instead!

Plastics are making a growing contribution to sustainable development. For example, over an expected lifetime of 50 years, the use of window frames and insulating materials made of plastic in buildings save many times the energy required to manufacture them. Plastics for packaging purposes provide protection against damage and dirt contamination, thereby saving considerable amounts of material and energy. Choosing appropriate disposal strategies for plastic waste also helps to protect the environment (Mark 2000).

Prediction of 3-dimensional turbulent flows around corner vane of a heavy-duty truck cab

The aerodynamic characteristics of large trucks have become more and more important in recent vehicle designs. Good aerodynamics improve performance in high-speed cruising and increase driving comfort. Hence, detailed knowledge of the flow field around corner vanes is essential to improved fuel efficiency and reduced dirty contamination on the vehicle body surface. In this study, 3-dimensional flow characteristics around a corner vane attached to a truck cab were computed for steady, incompressible, and high-speed viscous flow, adopting a RNG κ-e turbulence model. In order to investigate the influence of corner van configuration and structure, computations and actual diving tests were carried out for four different cases at a high Reynolds number, Re=4.1 x 106 (based on the cab height). The aerodynamic behaviour of global flow around the corner vane was examined. As a result of this study, we could identify the flow characteristics such as drag coefficient and mass flow rate passing the corner vane as a function of variation in the configuration and vane structure. Also, an improved corner vane structure is suggested to reduce dirt contamination on the cab sides.

All Aboard

This article reviews that testing the oil of diesel locomotives gives operators valuable information about engine operating conditions. Oil analysis is a tool for evaluating diesel engines for telltale signs of bearing and ring wear, heat degradation, and dirt contamination. However, the process of obtaining an oil sample is both costly and time-consuming. Typically, locomotives are taken into a service center, where an oil sample is drawn manually from the engine, put into a vial, and sent off to a laboratory for evaluation. OilPro will have predictive capability, offering rail roads the opportunity to improve maintenance scheduling. The service will provide diagnostic oil analysis that is currently supplied by offsite laboratories. OilPro can be expanded beyond oil sensing to monitor the overall health of the engine. Possibilities include looking at the electrical system and exhaust stack gases, and potentially vibration monitoring.

Efficacy of Leopard Tortoise (Gepchelone pardalis babcocki) Farming in Tanzania

Assessment of the efficacy of leopard tortoise farming was made in Dar es Salaam and Arusha between June and July 1995. Three out of four farms held parental stocks in excess of the legal quota. Some farms also held stocks of mixed provenance, unsuitable for farming. None of the farms had suitable enclosures. Drinking and bathing water was not changed frequently resulting dirt contamination. Few grasses and no mineral supplements were included in the tortoise diet. No regular veterinary inspection was made for parasite removal. The farms underreported tortoise deaths. The reproductive output of the captive tortoise was generally poor. Furthermore, farm owners lacked the expertise and commitment required for breeding tortoises in captivity. Farming cannot sustain the leopard tortoise export trade under the present breeding regime. The study concludes with recommendations for improving tortoise farming in Tanzania.

Prediction of dirt contamination on vehicle body surface

Abstract The contamination of the vehicle body surface reduces visibility through the rear window and makes the rear stop lamps invisible. In order to simulate this phenomenon by means of computational fluid dynamics, two different methods have been developed and examined. One is a `Dirt Particle Path Method' which calculates the motion equation of dirt particles, the other is a `Dirt Concentration Method' which calculates the diffusion equation of dirt. The results of simulations with these methods correspond to the real contamination pattern of the on-road tests.

Phenomenology of obsessions in a Turkish series of OCD patients.

Forty-five outpatients interviewed by using the Structured Clinical Interview for DSM-III-R, Outpatient version and diagnosed as obsessive-compulsive disorder were evaluated in terms of form and content of obsessions and compulsions. Obsessive-compulsive phenomena were classified according to a system proposed by Khanna and Channabasavanna. Depressive disorder was the most common comorbid diagnosis found in 73.2% of patients. The most prevalent obsession themes were daily activities and dirt contamination themes (64.4 and 53.3%, respectively). Religious themes were infrequent (11.1%) in the sample and Muslim culture seemed not to have a prominent impact on phenomenology of the disorder.

4—THE SYSTEMATIC OPTIMIZATION OF THE AQUEOUS COMPRESSION-JET WOOL SCOUR. PART IV: THE OPTIMUM CONDITIONS OF LIQUOR RECLAMATION AND THE ESTABLISHMENT OF EQUILIBRIUM

The equations representing the changes in the concentrations of the contaminants in scour liquors that were developed in Part 1 of this series are applied. The investigation of the optimum conditions of liquor reclamation took the form of two scouring trials. The results of these trials gave the recovery and removal efficiencies of the reclamation units and showed that two centrifuges in parallel very efficiently removed the grease and dirt contaminants from the scour liquor. The investigation of the determination of equilibrium conditions of the contaminants in the scour liquor consisted in scouring wool for 6 hr without back-flow or liquor reclamation. The results showed that effective continuous scouring was feasible. Experimental results of contaminant concentrations in the liquors compared favourably with the predicted values obtained from equations.

Air cleaning features for traction equipment

THE EFFECT of dirt on the life and general performance of electric equipment has been the subject of previous papers and discussions. Dirt is not a unique phenomenon on traction equipment alone. Industrial installations have the same or similar problems. Mention need be made only of electrical installations in such places as cement factories, chemical plants, mines, etc., where the dirt probelm is also serious. However, what makes the traction field different is that the electric equipment is part of a moving vehicle, that it is for the most part perhaps the least accessible of all electrical installations, and that failures of electric equipment will generally stop the traction vehicle somewhere remote from help and replacement parts, and thereby tie up a transportation system. Hence, there arises the interest in and need for features to keep traction equipment clean and prevent breakdowns because of dirt contamination.