Paraffin Wax

N This technique allows the direct correlation of genetic abnormalities to immunophenotype, and will be particularly useful for the identification of genetic abnormalities in specific tumour cells present in BMTs N The application of this technique in routine clinical practice will assist diagnosis and the detection of minimal residual disease

Availability of solar energy as a renewable energy source is very abundant and inexhaustible. Solar water heater is an equipment that utilizes solar energy as a source of energy. The thermal performance of a solar water heater system using absorber plate with phase change material (PCM) as thermal energy storage is presented in this study. Two design of solar water heater collectors with absorber plate variations, i.e. an absorber plate with PCM storage and absorber plate without PCM storage were investigated experimentally and numerically simulation. First, the material properties of paraffin wax as PCM storage was analized analyticaly. Every shape model of solar water heater systems were imported and simulated at three variations of constant solar radiation, i.e. 400  W/m2, 700 W/m2, and 1000 W/m2. The simulation using a computational fluid dynamic (CFD) fluent software. The results showed that the average collector efficiency between absorber plate with and without PCM storage is...

Ocular melanomas embedded in paraffin wax for histological examina- tion have been studied by electron spin resonance (ESR) spectroscopy. A free-radical signal was detected at the g=2.003 section of the spectrum. The amplitude of this signal was correlated with the number of melanin granules in microscopical slides made from the tumour. This positive correlation can make ESR spectroscopy suitable for estimating the melanin content in the embedded melanoma blocks. Additional paramagnetic signals can also be detected. The clarification of their significance needs, however, further ESR measurements.

The structure of Iraqi paraffin wax is found to be straight chain with no branching or unsaturation, with an average fonnula of C~4 H 70 and an average molecular weight of 471. The effect of gam.na radiation on pure wax is to give degradation products con• taining so.ne unsaturation. Cross-linking of these frag.nents, which occurs at 60 Mrads, give products of .nolecular weight less than twice the original. The effect on wax-acetone syste.n (an e.nulsion) is that no degredation or cross-linking is observed, using up to 115.2 Mrads, thus there is co.nplete protection by acetone. This emulsion case has not been reported before, and the Do.nain Effect is used for its explanation.

In this paper, the increase of the effective thermal conductivity of paraffin based heat sinks is investigated by making use of cellular metallic matrixes with open cells which are introduced in the thermal low conductive paraffin wax. Lattice Monte Carlo analyses are conducted on different model geometries of such composites composed of a cellular matrixes and paraffin wax. The dependence of the effective thermal conductivity on the cell geometry and the metal foam matrix material is analysed. Furthermore, a diamond coating is simulated in order to estimate its influence on the effective thermal conductivity.

In this paper, the increase of the effective thermal conductivity of paraffin based heat sinks is investigated by making use of cellular metallic matrixes with open cells which are introduced in the thermal low conductive paraffin wax. Lattice Monte Carlo analyses are conducted on different model geometries of such composites composed of a cellular matrixes and paraffin wax. The dependence of the effective thermal conductivity on the cell geometry and the metal foam matrix material is analysed. Furthermore, a diamond coating is simulated in order to estimate its influence on the effective thermal conductivity.

This study explores the practical application of fin-enhanced beeswax as a thermal energy storage (TES) medium in hybrid solar and liquefied petroleum gas (LPG) powered poultry egg incubators to enhance energy and hatchery efficiency. A system with a double-glazed flat plate solar collector, a fin-enhanced beeswax TES, an incubation chamber, and an LPG backup was designed and tested. The results show that the design effectively maintained incubation temperature between 37.2 and 38.6 ○ C and relative humidity between 50% and 65%, while that of the ambient environment ranged between 39% and 88%. The solar collector and TES material's thermal efficiency were 67% and 68%, respectively, while hatchery efficiency was 70%. This result suggests that the beeswax-integrated hybrid egg incubator is an efficient and viable energy solution for the sustainability of incubation practices in regions with unreliable grid electricity, particularly in developing countries. The system helps improve food security by reducing energy use and the environmental impact of traditional methods.

Thermophysical characterization of three paraffin waxes (RT27, RT21 and RT35HC) is carried out in this study using DSC, TGA and transient plane source technics. Then, a numerical study of their melting in a rectangular enclosure is examined. The enthalpy-porosity approach is used to formulate this problem in order to understand the heat transfer mechanism during the melting process. The analysis of the solid-liquid interface shape, the temperature field shows that the conduction is the dominant heat transfer mode in the beginning of the melting process. It is followed by a transition regime and the natural convection becomes the dominant heat transfer mode. The effects of the Rayleigh number and the aspect ratio of the enclosure on the melting phenomenon are studied and it is found that the intensity of the natural convection increases as the Rayleigh number is higher and the aspect ratio is smaller. In the second part of the numerical study, a comparison of the performance of paraf...

Carbon adsorbents with different properties were obtained from furfural and mixture of furfural and polymer waste (polyolefine wax) with different activation reagents and different conditions of treatment. The carbons obtained have insignificant ash content. It was determined, that pore volume, pore size distribution and the chemical character of the surface of the carbon adsorbents depend on the selected activation reagents and temperature of treatment. The IR spectra and Boehm method show that various oxygen-containing groups with acidic (carboxylic, carboxylic in lactonelike bonding, phenolic, hydroxyl and carbonyl groups) and basic character are present on the carbon surface. Our investigations reveal that on the base of polymer waste, different activated carbons were obtained, and they could be used as effective adsorbents for removal of toxic metal and organic pollutants.

Effective usage of solar air heaters (SAH) is limited to specific time due to nonavailability and low intensity of solar radiation. In addition, SAH suffers from lower thermal efficiencies. Encapsulated phase change material (PCM) on absorber plate of SAH is one of the passive techniques to improve thermal efficiency of SAH as well as to extend its application to nonsunshine hours. In this article, capsules of circular and square cross sections filled with PCM were used on absorber plate of a double pass counter flow SAH and SAH efficiency was experimentally determined. Capsules were placed in inline and staggered grid arrangements perpendicular to the flow direction of the air and paraffin wax was used as the PCM. Experiments were conducted each day in two cycles (charging PCM from 10:00 AM to 2:00 PM and discharging PCM from 4:30 PM to 5:30 PM), with fixed mass flow rate of air in between 0.00879 and 0.01484 kg/s. It is found from the results that, efficiency of SAH with square staggered encapsules is at an average of 15.8% higher than the remaining arrangements. During PCM discharge, air temperature at the SAH exit was at an average of 5.17 C greater than ambient temperature for all arrangements. double pass solar air heater, encapsules, latent heat storage material, paraffin wax, phase change material

The tissue microarray (TMA) is a powerful tool for cancer biomarker discovery and validation. Tens to hundreds of samples can be evaluated simultaneously for molecular marker status at the protein or nucleic acid level. Although fully automated or semiautomated technologies for TMA creation provide excellent precision with respect to core transfer, they do not obviate the need for technical expertise to successfully generate highquality TMA blocks and derivative sections. We have leveraged our expanding bank of formalin-fixed paraffin embedded paired tumor and normal tissues in our academic cancer center to provide a rich source of input material for cancer research TMAs. In this study, we report a stepwise optimization of TMA generation parameters, including paraffin wax selection, tempering protocol, and sectioning conditions, to achieve the best ribbon sectioning.

Paraffin wax stores energy in the form of latent heat at a nearly constant temperature during melting and releases this energy during solidification. This effect is used in industrial energy storage. An unusual change in the shape of a melted droplet of paraffin wax placed on a relatively cold glass plate is studied. As the droplet solidifies, its upper surface becomes nearly flat and a dimple is formed in the center of this surface, making the droplet look like a fruit (pumpkins are more commonly shaped like this, but the authors prefer apples). A series of experiments, as well as physical and numerical modeling of the droplet's thermal state, taking into account the formation of a mushy zone between liquidus and solidus, made it possible to understand the role of gravity and gradual increase in viscosity and density of paraffin wax on changing the droplet shape and, in particular, to clarify the mechanism of formation of the dimple on its upper.

A two-dimensional computer simulation is presented for conjugate heat transfer and solid±liquid phase change, concurrently occurring within a domain of the paran wax±air spiral thermal energy storage unit during its charging and discharging. The numerical model is based on local energy balances in a set of curvilinear control-volumes (the domain of the unit is divided into), and on the enthalpy approach to account for the latent heat eect. The results obtained are compared with the experimental data, reported in the authors' earlier paper (Banaszek J., DomanÄ ski R., Rebow M. and El-Sagier F., Experimental study of solid±liquid phase change in a spiral thermal energy storage unit, Applied Thermal Engineering 19 (1999) 1253±1277), to ®nd out that the proposed numerical model is a reliable and suciently accurate calculation tool, although some incongruity between calculated and measured temperature of the paran wax exists. The reasons for this discrepancy are thoroughly analyzed and discussed in the paper.

In the petroleum industry, still a major problem is the deposition of paraffin wax especially during exploitation in Deepwater field. This study is aimed at characterizing crude oil sample, understanding the characteristic of paraffin wax and testing the solubility of the precipitated wax in xylene and kerosene at different blend ratios. The crude oil sample which was obtained from Eleme community in Niger Delta, Nigeria, was characterized and the cloud point and pour point were obtained as 20 o C and 12 o C respectively. Results obtained from the solubility test shows that 100% Xylene dissolves 99.4% of the precipitated wax in 150 min and 90.1 % in 90 min. While for same quantity 100% kerosene shows solubility of 35.4% in 150 min and 26.2% in 90 min which implies that xylene although expensive is a better solvent for paraffin wax cleanup when compared to kerosene. At different xylene – kerosene blend ratios, the blend of 70:30%, Xylene: Kerosene mixture also gave an excellent resul...

The typical batik wax compositions used in Malaysia consist of various blends of beeswax, dammar, rosin, paraffin, and microcrystalline wax. This study aims to characterize soy wax/beeswax blends' structural, thermal, strength, and mass loss properties as potential alternative batik wax compositions. The Fourier transform infrared spectroscopy (FTIR) results showed that the additions of beeswax (wt%) into soy wax resulted in possible chemical interaction for the esters (C=O stretching and C-H bending vibrations), hydrocarbons (CH2 scissor formation), and cholestral esters (C=O stretching vibrations). The thermal profile obtained via differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) respectively revealed an increase in peak melting temperature and reduced thermal stability of the blends with further increments of beeswax. In addition, beeswax enhances the compression strength by 150% but did not have any significant impact on the modulus of the blends. Evaluation of the mass loss test suggested that beeswax in the range of 40 wt% to 60 wt% can be considered as alternative batik resist material due to its moderate leaching tendency. Future works shall be conducted to evaluate the performance of these wax compositions against other batik wax criteria and the feasibility of printing these waxes using an in-house designed batik printer.

To prepare and modify different wax compositions in order to find out the most suitable formula that has almost the same properties of dental modeling wax used in dentistry. Materials and Methods: Three groups of waxes (220 samples) with different compositions regarding its origin (Al-Dora refinery waxes, natural bees wax-North of Iraq, and commercially available Iraqi waxes), additives such as starch, sodium-carboxyl methylcellulose (Na-CMC), rosin, or nylon, and coloring agents were prepared. The samples were tested for their melting range, 21 samples only had a melting range that nearly coincides with that of the dental waxes such as Major and Cavex. Results: The resultant 21 samples were tested for their softening, trimming, penetration, residue materials and solubility. Only 4 samples showed properties that are closely similar to that of Major and Cavex wax. The results of melting point ranged from 69-80 o C. Softening test showed that the samples which contain nylon, Na-CMC, or rosin were softened without adhering to the fingers. Trimming test showed that they were trimmed easily and clearly. Penetration test showed that, some samples had the similar measurements of Major and Cavex wax (0.6-0.9mm). Residue materials showed that all samples had no residue of wax materials on acrylic teeth after wax elimination procedure. All the prepared waxes were soluble in ether (acetone), and petroleum spirit (benzene). Conclusion: Six new modeling wax materials were prepared according to ADA specification No.24. Three of new wax materials consist of nylon (polystyrene 1.71-2.13%); the other two novel modeling waxes were fabricated by using additive materials (Na-CMC and rosin).

Groundwater contamination is a very serious problem as it leads to the deterioration of groundwater resources. Saltwater intrusion is a special category of groundwater contamination that threatens the health and possibly lives of many people living in coastal areas. The installation of injection of treatment water is among several methods proposed to control saltwater intrusion on coastal groundwater system. In this research, a twodimensional numerical model is developed for simulating both groundwater flow and saltwater intrusion of Quaternary Aquifer in Delta Wadi El-Arish (QADWA). The sharp interface philosophy is adopted to simulate dynamics of freshwater flow. The proposed model applied a coupled Finite Element Method (FEM) and Finite Difference Method (FDM) to predict the temporal migration of interface toe due to injection of treatment water. Model calibration is carried out to determine the physical parameters of the proposed model. Then, model verification and validation are established by comparing model results with the actual measurements. This study is considered a trial to present a solution for the problem of saltwater intrusion by finding general relationships between average distances of saltwater intrusion and injected rates of treatment water. Then, the suitable value of recharged water can be mathematically determined. The results obtained from this study are useful in management schemes of saltwater intrusion mitigation in coastal areas.

The melting process of paraffin wax placed in storage capsules of different shapes was experimentally and numerically studied. The phase change material (PCM) was initially at 27 °C. The effect of the mushy zone parameter (Amush) value on the melting process of the PCM was studied with storage capsules of different shapes (circular, vertical oval, and horizontal oval). The results of the numerical model were validated with the experimental results to obtain the optimum Amush value for each shape of the latent heat storage unit. The results showed that the value of the Amush has a great impact on the numerical results of the PCM melting process and changes with the shape of the storage capsule. The rate of heat transfer, convection, and fluid velocity all decrease as the Amush value rises. The experimental results of the circular, vertical oval, and horizontal oval capsules match very well with the numerical model with Amush values equal to 2 × 106, 1 × 105, and 1 × 106, respectively.

To reduce the cost of materials in a thermal energy accumulator, the use of water as a substitute for a mass fraction of paraffin wax was considered in the present study which evaluates the thermal behavior of a combined sensible and latent heat storage system that used a beverage can containing paraffin wax and water in different proportions for experiences of thermal energy accumulation and discharge. Unlike other applications that consider the forming of emulsions, there will be two phases within the containers. In a second stage, energy discharge experiences were realized within a 12 cans laboratory scale energy accumulator to analyze its thermal behavior. Replacing 25% of paraffin wax decreases the accumulated energy by only 12%, retaining similar energy discharge times relative to a 100% paraffin wax configuration. Shorter energy loading times and higher heat removal were observed for configurations with a higher water content. No major differences in energy discharge efficiency were found for the same wax / water content, using air velocities of 1.3 m/s and 2.6 m/s. However, in the first 60 minutes differences up to 25% in the heat removal were observed. Heat transfer coefficients between 18.0 W/m 2 K and 26.8 W/m 2 K were determined experimentally.

This work focused on experimental investigation of using a novel phase change material (PCM) in a PV module to enhance its cooling performance. Phase change material by absorbing a lot of heat from the surface of the PV module and control the heat capacitance of the system causes to raising its overall efficiency. In order to postpone the melting of the PCM material, copper microchannel tubes in which cold water is flowing is used and located in a chamber at the backside of the PV module. At first step of experiments, sheep fat has been used as a novel PCM and secondly; in order to increase the cooling efficiency of the sheep fat, CuO nanoparticles (0.004 (w/v)) have added to it. The results of the pure sheep fat and sheep fat+CuO nanoparticels have been compared with the layout of using paraffin wax as a conventional PCM. The obtained results of surface temperature, maximum power increase and electrical efficiency of the PV module for using each PCM materials have been compared. Results show that using both PCMs (sheep fat and paraffin wax) can enhance the cooling performance of the studied PV module; however, sheep fat is more efficient rather than the paraffin wax. In addition, results depicted that adding CuO nanoparticels in the sheep fat causes to significantly decrease in the average temperature of PV module surface. The research experiments of using sheep fat+CuO nanoparticels confirm that the maximum generated power is increased about 24.6% to 26.2% compared with the layout of no cooling system and 5.3% to 12% compared to paraffin wax.

Transportation of paraffinic crude in a cold environment can result in wax depositions, which are solid deposits, on the pipe wall. The formation of paraffin in the bulk of the petroleum is a crystallization process in solution. Such phenomenon occurs along the pipe connected to offshore wells and even onshore. Its main implication is a paraffin blockage with serious economical consequences. This work aims to learn about paraffin deposit formation using a cold finger methodology, in two types of Brazilian crude oils (32 API and 20 API). The polythermal method is used in various experiments using different temperatures in both cold finger and bulk of the fluid. The experiments measure: the thickness of the deposits, as well as the deposition rates, degree of subcooling and, finally, the induction for the onset of wax. The methodology allows the evaluation of the critical time of deposition and the critical temperature difference between the hot petroleum source and the cold seawater temperature. It is shown that the deposit rate depends on this temperature difference, as well as the cooling surface, the nucleation kinetics and the growth of the crystals on the cold finger surface. The work discusses carefully the experiments design under the light of dimensional analysis. The values of critical temperature differences are relatively small and show that the encrustation is easily attained in the offshore petroleum flow. The methodology implemented is simple and allows the prediction of very important information about the mechanism of paraffin encrustation that could pave the way to avoid paraffin deposition in offshore petroleum production due to high temperature differences between the heat petroleum sink source and the cold seawater.

Partially hydrogenated soybean oil, referred to as soywax, is gaining attention as a renewable and biodegradable alternative to paraffin wax for use in candles. However, current soywax candles suffer from several problems, especially poor melting and solidification properties. Fully hydrogenated soybean oil exhibits improved melting properties but owing to its fragile texture, it is not yet acceptable in most candle applications. In the present work, KLXTM (a wax composed of fractionated hydrogenated soy and cottonseed oils) was used as a base material for candles, and the effects of additives such as hydrogenated palm oil (HPO), FFA, and paraffin on the textural and combustion properties were evaluated. Melting and solidification profiles of KLX were better than those of fully hydrogenated soy oil. Adding FFA improved the solidification properties of KLX candles. Adding paraffin improved the compressibility of the wax, while HPO addition decreased hardness and compressibility. Chan...

Purpose. Storing thermal energy has emerged as a solution for improving energy efficiency by recovering waste heat. Improving heat transmission rates in thermal energy storage (TES) systems is crucial to the TES thermal efficiency. This research examines the thermal efficiency of the TES unit of a star snowflake fractal cross-section loaded with nano-enhanced phase change materials (NEPCM). Design/methodology/approach. The porous enthalpy approach is used to represent the phase transition development. The impacts of nanoparticle concentrations (-j = 0 8%), the location of the inner tube (down, center, low), and the wavy number of the external shell (N = 4, 6, 8) are presented and analyzed. Findings. The obtained numerical findings indicated that increasing j and N, besides placing the inner tube at the lower part of the TES system, enhanced the heat transmission rates and reduced the discharging time of the NEPCM. It was noted that positing the inner tube in the bottom section of the TES system and using an undulation number of 8 improved the heat transmission rate by 66% and 7.6%, respectively. On the other hand, the NEPCM melting time was decreased by 25% when j = 8%.

This paper reports investigation on the thermal performance of a new configuration of solar collector integrating a paraffin wax. This configuration, called Solar-PCM Wall (S-PCMW), is aimed for domestic hot water production and reduction of heat transferred from outside under the tropical climate of Thailand. The S-PCMW consisted of a glaze pane, air gap, black-painted pipes 0.01 m. in diameter, a 1 cm paraffin wax tank made from steel, and insulator. The S-PCMW can hold approximately 10 litters of water and its total thickness is 0.12 m. Comparison between S-PCMW and Simple Concrete Wall (SW) using two small house models of the same volume (4.05 m 3 ) was presented and discussed. The experimental results revealed that indoor temperature of the room mounted with S-PCMW was lower than that utilizing SW. Heat gain through the south wall of S-PCMW decreased considerably when compared with the another type. The S-PCMW could produce hot water at temperature varying between 45-51ºC. Thus, it has been proved that the S-PCMW is efficient in terms of heat gain reduction and hot water production. Additionally, it could help to promote solar systems integration in buildings and residences.

This paper reports investigation on the thermal performance of a new configuration of solar collector integrating a paraffin wax. This configuration, called Solar-PCM Wall (S-PCMW), is aimed for domestic hot water production and reduction of heat transferred from outside under the tropical climate of Thailand. The S-PCMW consisted of a glaze pane, air gap, black-painted pipes 0.01 m. in diameter, a 1 cm paraffin wax tank made from steel, and insulator. The S-PCMW can hold approximately 10 litters of water and its total thickness is 0.12 m. Comparison between S-PCMW and Simple Concrete Wall (SW) using two small house models of the same volume (4.05 m 3 ) was presented and discussed. The experimental results revealed that indoor temperature of the room mounted with S-PCMW was lower than that utilizing SW. Heat gain through the south wall of S-PCMW decreased considerably when compared with the another type. The S-PCMW could produce hot water at temperature varying between 45-51ºC. Thus, it has been proved that the S-PCMW is efficient in terms of heat gain reduction and hot water production. Additionally, it could help to promote solar systems integration in buildings and residences.

This experiment is based on enhancing the productivity of a conventional solar still by using techniques that have newly materialized. The modifications include using Aluminum Oxide (Al2O3) nanoparticle to produce Nanofluid (0.2% concentration) and Paraffin Wax as Phase change material (PCM) together in the still which is expected to facilitate production of more fresh water. The outdoor performance of modified solar still is studied to assess its potential for real application. It is compared with the results of a conventional solar still to better understand the effects of the modifications. It was observed that, on consecutive days, the conventional still had an efficiency of 10.15% whereas the modified still had a daily efficiency of 13.15%, 16.40% and 14.47% for three consecutive days under similar conditions of environment.

Many plants in fire-prone regions retain their seeds in woody fruits in the plant canopy until the passage of a fire causes the fruit to open and release the seeds. To enable this function, suitable tissues are required that effectively store and protect seeds until they are released. Here, we show that three different species of the Australian genus Banksia incorporate waxes at the interface of the two valves of the follicle enclosing the seeds, which melt between 458C and 558C. Since the melting temperature of the waxes is lower than the opening temperatures of the follicles in all investigated species (B. candolleana, B. serrata, B. attenuata), we propose that melting of these waxes allows the sealing of micro-fissures at the interface of the two valves while they are still closed. Such a self-sealing mechanism likely contributes to the structural integrity of the seed pods, and benefits seed viability and persistence during storage on the plants. Furthermore, we show in a simplified, bioinspired model system that temperature treatments seal artificially applied surface cuts and restore the barrier properties.

Dalam industri manufaktur dan pulp, teknologi perpindahan panas memainkan peran penting dalam meningkatkan efisiensi energi dan keberlanjutan proses produksi. Heat exchanger, seperti tipe shell and tube serta plate-frame, telah terbukti efektif dalam mentransfer panas antar fluida, yang berkontribusi pada penghematan energi dan pengurangan emisi gas rumah kaca. Selain itu, pemanfaatan energi terbarukan, seperti gasifikasi black liquor dan sludge, menawarkan solusi alternatif untuk mengurangi ketergantungan pada bahan bakar fosil.

Nama : Benri Mario Sijabat NIM : 012.22.004 Matkul : Aplikasi Perpindahan Panas Ketergantungan Industri pulp pada gas alam apalagi pada produksi yang menggunakan proses kraft membuat kesulitan dalam pengendalian kebutuhan energinya secara mandiri. Selama prosesnya, industri ini menghasilkan limbah berupa sludge dari pengolahan air limbah serta produk samping bernama Black Liquor. Salah satu solusi yang bisa diterapkan adalah sistem gasifikasi, yang mampu meningkatkan efisiensi energi dengan mengubah limbah menjadi bahan bakar dan gas sintetis. Jurnal ini membahas bagaimana industri pulp dan kertas dapat memanfaatkan kembali limbahnya melalui gasifikasi, sehingga tidak hanya mengurangi limbah tetapi juga menciptakan sumber energi alternatif. Berdasarkan penelitian dan literatur yang ada, gas hasil gasifikasi dari sludge dan Black Liquor berpotensi menjadi bahan bakar alternatif yang lebih ramah lingkungan .

Artikel ini membahas sebuah pemanfaatan limbah industri pulp dan kertas , seperti sludge dan juga black liquor , sebagai sumber energi alternatif dengan menggunakan proses gasifikasi untuk mengurangi ketergantungan pada gas alam . Gasifikasi sludge menghasilkan

Jurnal ini merupakan hasil review dari 5 jurnal yang berkaitan dengan Perpindahan panas. Jurnal ini ditujukan sebagai tugas mata kuliah Perpindahan Panas pada Fakultas Vokasi Prodi Teknologi Pengolahan Pulp & Kertas, Institut Teknologi Sains Bandung

The production and transportation of petroleum uids will be severely a ected by the deposition of suspended particles (i.e. asphaltenes, diamondoids, para n/wax, sand, etc.) in petroleum uid production wells and/or transfer pipelines. In certain instances, the amount of precipitation is rather large causing complete fouling of these conduits. Therefore, it is important to understand the behavior of suspended particles during petroleum uid ow conditions. In this paper, we present an analytical model for the prefouling behavior of suspended particles corresponding to petroleum uids production conditions. We predict the rate of particle deposition during various turbulent ow regimes. The turbulent boundary layer theory and the concepts of mass transfer are utilized to model and calculate the particle deposition rates on the walls of owing conduits. The developed model accounts for the eddy di usivity and Brownian di usivity as well as for inertial e ects. The analysis presented in this paper shows that rates of particle deposition (during petroleum uid production) on the walls of the owing channel due solely to di usional e ects are small. It is also shown that deposition rates decrease with increasing particle size. However, when the process is momentum controlled (large particle sizes), higher deposition rates are expected.

Karya tulis ini membahas optimalisasi efisiensi energi dalam industri melalui pemanfaatan energi alternatif dan teknologi perpindahan panas. Fokus utama terletak pada pemanfaatan gasifikasi limbah industri pulp sebagai sumber energi alternatif serta penerapan berbagai jenis penukar panas (heat exchanger) seperti plate-frame dan shell and tube untuk meningkatkan efisiensi termal di sektor pembangkit listrik dan manufaktur. Selain itu, dibahas pula potensi material perubahan fase (PCM) dalam sistem penyimpanan energi thermal yang mampu menjaga kestabilan suhu dan efisiensi penyimpanan. Studi literatur menunjukkan bahwa kombinasi teknologi tersebut mendukung keberlanjutan dan penghematan energi, meskipun terdapat tantangan teknis dan ekonomi dalam penerapannya. Keseluruhan kajian ini menekankan pentingnya inovasi dan pengembangan berkelanjutan dalam teknologi perpindahan panas untuk meningkatkan efisiensi energi industri.

Review ini mengkaji lima jurnal yang berfokus pada peningkatan efisiensi energi dan manajemen termal melalui teknologi seperti heat exchanger, fuel cell, dan material perubahan fasa (PCM). Penelitian menunjukkan bahwa penerapan heat exchanger tipe shell and tube serta plate-frame secara signifikan meningkatkan efisiensi perpindahan panas di sektor industri. Selain itu, fuel cell diteliti sebagai alternatif energi ramah lingkungan yang membutuhkan pengelolaan suhu optimal dan reformasi gas hidrogen. PCM diidentifikasi sebagai solusi penyimpanan energi termal yang efisien berkat kemampuannya menyerap dan melepaskan energi laten secara efektif. Integrasi ketiga teknologi ini berpotensi menciptakan sistem energi yang lebih berkelanjutan dan ramah lingkungan, dengan pengaruh besar pada pengurangan konsumsi bahan bakar fosil dan peningkatan efisiensi operasional industri.

Phase change materials (PCMs) serve as an advantage in thermal energy storage systems utilizing the available sensible and latent heat. The PCMs absorb the thermal energy during the charging process and release it into the environment during the discharging process. Steatite is low cost and eco-friendly, with a thermal stability up to 1000 • C, and it is abundantly available in nature. This study investigates the steatite-paraffin wax-based PCM and the effect on the cyclic loads using a horizontal triplex-tube latent heat energy storage system. The thermal conductivity value of the milled steatite-based PCM composite was 7.7% higher than pure PCM. The PCM with the ball-milled steatite-fabricated composite exhibited better discharging characteristics, increasing the discharge time by 50% more than that of the pure paraffin wax. Moreover, the milled steatite-based PCM outperformed that incorporated with non-milled steatite with paraffin.

Artikel ini membahas sebuah pemanfaatan limbah industri pulp dan kertas , seperti sludge dan juga black liquor , sebagai sumber energi alternatif dengan menggunakan proses gasifikasi untuk mengurangi ketergantungan pada gas alam. Gasifikasi sludge menghasilkan

Artikel ini membahas sebuah pemanfaatan limbah industri pulp dan kertas , seperti sludge dan juga black liquor , sebagai sumber energi alternatif dengan menggunakan proses gasifikasi untuk mengurangi ketergantungan pada gas alam. Gasifikasi sludge menghasilkan

One of the most effective methods of solar water desalination without energy exhaustion is the use of thermal energy storage materials such as paraffin wax (PCM). These materials have been approved as one of the most acceptable alternatives for energy supply in distillation plants. These materials (sensible and latent) are used in the solar still to store energy in sunshine hours and release in evening hours to increase production at nighttime. In this study, the effect of using PCM Cells was investigated experimentally in a rectangular-basin solar still with a single slope, and according to Kirkuk city climate in Iraq. Two solar stills were investigated in the current work using two different techniques for the desalination process. The first type (A) is a simple type saline water distiller, which represents the conventional distiller with single inclined from the horizontal (30 degrees). The second type (B) is a suggested type with an integrated PCM in the basin. The basin coated with black colour to absorb the greatest amount of solar energy. Amount of water distilled produced from the two patterns collected in a similar working condition and compared to indicate the performance enhancement. The results showed that starting from the early hours till 5 pm, the accumulated water volumes for solar distillation type A is more than that of solar distillation type B, due to the absorbed part of solar heat energy (charging process) by the PCM. After 5 pm the productivity of type B becomes more than type A, where the paraffin wax becomes a source of heat energy up to the end of the day (discharging process). Generally, the ratio of water productivity for type B is increased by about 32% than that of type A over the long day period.

Aims: We studied the prevalence of HGV-RNA in serum by reverse PCR and determined antibodies against the envelope protein E2 of HGV by ELISA in 83 patients with welldefined autoimmune hepatitis (AM). Methods: HGV-RNA was detected by reverse transscription PCR with nested primers from the non-structural region 3. Sequence data were obtained by an automatic sequenzer. Anti-E2 antibody, a marker of past infection, was measured by ELISA. Results: HGV-RNA was found in 11 of 83 patients (13%) as compared with 2% of healthy controls (p=O.O12). Anti-E2 was observed in 15 (18%) patients which was not different from healthy controls (12 out of 93; ns.). Only 1 patient had both HGV-RNA and anti-E2 present in serum at the same time. HGV-RNA was found in 8% of type I AIH, but in 23% and 14% of type II and type III AIH, respectively. Conversely, 26% of type I, but only 12% and 7% of type II and type III AlH had anti-E2. Exposure to HGV (HGV-RNA+ or anti-E2+) was similar in all three types (34%, 35%, 2 1%)). Sequence analysis of HGV in the 11 positive patients revealed infection with only one single genotype of HGV (type 2b). Conclusions: Patients with AIH have an increased risk for HGV infection. Patients with type I AIH are more likely to show anti-E2 as a marker of past HGV infection. Only a single genotype of HGV-RNA was present in our population of patients with AIH.

Thermal storage system (TES) with phase change material (PCM) is an important device to store thermal energy. It works as a thermal buffer to reconcile the supply energy with the energy demand. It has a wide application field, especially for solar thermal energy storage. The main drawback is the low value of thermal conductivity of the PCM making the system useless for thermal engineering applications. A way to resolve this problem is to combine the PCM with a highly conductive material like metal foam and/or nanoparticles. In this paper a numerical investigation on the metal foam effects in a latent heat thermal energy storage system, based on a phase change material with nanoparticles (nano-PCM), is accomplished. The modelled TES is a typical 70 L water tank filled with nano-PCM with pipes to transfer thermal energy from a fluid to the nano-PCM. The PCM is a pure paraffin wax and the nanoparticles are in aluminum oxide. The metal foam is made of aluminum with assigned values of porosity. The enthalpy-porosity theory is employed to simulate the phase change of the nano-PCM and the metal foam is modelled as a porous media. Numerical simulations are carried out using the Ansys Fluent code. The results are shown in terms of melting time, temperature at varying of time, and total amount of stored energy.

A numerical investigation on Latent Heat Thermal Energy Storage System (LHTESS) based on an aluminum foam totally filled with phase change material (PCM) is accomplished. The PCM used is a pure paraffin wax with melting over a range of temperature and a high latent heat of fusion. The LHTESS geometry under investigation is a vertical shell and tube. The corrugated internal surface of the hollow cylinder is assumed at a constant temperature above the PCM melting temperature. The other external surfaces are assumed adiabatic. The paraffin wax phase change process is modelled with the enthalpy-porosity theory, while the metal foam is considered as a porous media obeying to the Darcy-Forchheimer law. Local thermal non-equilibrium (LTNE) model is assumed to analyze the heat transfer in the metal foam. The governing equations are solved employing the Ansys-Fluent code. The numerical simulations results, reported as a function of time, and concerning the LHTESS charging phase, are compared...