Side Of Shell Research Articles

Usage potential and benefits of processed coconut shells in concrete as coarse aggregates

As concrete consumes a lot of natural resources, sustainable growth is challenging. Around the world, 7.23 billion tonnes of concrete is produced annually, necessitating a significant quantity of aggregates to meet construction demands. Therefore, it is crucial to explore alternatives to coarse aggregates, which make up roughly 70–80% of the overall volume of the concrete. Additionally, waste management is a global concern that is exacerbated by up to 15% due to coconut shell trash. India ranked third in the world for coconut production in 2018, is particularly affected by this issue. This study investigates the usage of coconut shells in place of coarse aggregate. Owing to the high-water absorption of coconut shells, presoaked coconut shells were replaced as coarse aggregate with 5, 10, 15, 20, and 25% in M30 grade concrete. Slump, density, compressive strength, and microstructural characteristics were studied and evaluated. It is observed that, due to the presence of the plain surface on one side of the coconut shell, the workability of the concrete increased as the percentage of coconut shells increased. Because of the lower specific gravity of coconut shells, concrete produced by 15% replacement of coarse aggregates, reduced the density of the concrete by 7% when compared to the conventional concrete. The 28-day compressive strength of 15% coconut shell replaced concrete showed a 24% strength reduction compared to conventional concrete. C-S-H gel formation was evident from SEM analysis. It is important to note that the compressive strength of coconut shell aggregate concrete at 3, 7, 14, and 28 days, decreased rapidly beyond the 15% replacement of coarse aggregates. It has been found that concrete may be produced without impacting performance qualities when coconut shell aggregates are used in place of natural aggregates at an optimal replacement of 15%.

Au nanorod core in an AgPt cage: Synthesis of Au@AgPt core/cage nanoframes with rough surface and controllable geometry by galvanic replacement

Metallic nanoparticles with intricate nanoframe structures have provoked extensive attention for improving optical and catalytic properties owing to their open structures. However, how to precisely control the geometry shape and surface details of the nanoframes remains a daunting challenge. Herein, we report a novel structure of Au@AgPt core/cage nanoframes with rough surfaces and controllable geometry and surface details based on the galvanic replacement reaction between Ag shells wrapped around gold nanorods and Pt4+ ion. With the increase of Pt4+ ion, the six faces of Ag shell firstly undergo a continuous concaving process to form the concave surface, following by an asymmetric and continuous hollowing-out process started from one side of Ag shell, and in this whole process accompanied by re-deposition process of both silver and platinum on the edges and vertices. We also verify that the prepared Au@AgPt nanoframes have the characteristics of adjustable size, aspect ratio, roughness, skeleton diameter and composition ratio by changing these reaction conditions such as temperature, thickness of Ag layer, and aspect ratio of gold nanorod. This controlled shape evolution also results in abundant localized surface plasmon resonance (LSPR) modes. Multiple absorption bands could be tuned simultaneously from blue (400 nm) to near infrared (1300 nm) range.

First Documented Record of Sineancylus rosanae (Gutiérrez Gregoric, 2012) (Mollusca: Planorbidae: Ancylinae) in Southern Brazil

Sineancylus rosanae (Gutiérrez Gregoric, 2012) is a freshwater limpet that has its apex located along midline on the anterior side of shell, different from other species of Ancylinae. Previously, it was considered a species of Laevapex in the Brazilian states of Paraná and Rio Grande do Sul. Agudo-Padrón (2007) also mentioned Laevapex sp. without giving a precise locality or an image of the material in question. Therefore, it is unknown if this record was really a Laevapex species or a misidentified Sineancylus. Due to its rarity, limited distribution, and its peculiar characters, herein we provide a proper record of S. rosanae from the state of Paraná, Brazil, expanding its known distribution. A population of S. rosanae was discovered in the Ocoí River (municipality of Medianeira) attached to basalt stones in the middle of the river. The shells analyzed in this study closely fit the original description.

Supernova remnant G46.8–0.3: A new case of interaction with molecular material

Although the Galactic supernova remnant (SNR) G46.8–0.3 has been known for more than 50 yr, no specific studies of this source or its environment have been published to date. To make progress on this matter, we measured new flux densities from radio surveys and combined them with previous estimates carefully collected from the literature to create an improved and fully populated version of the integrated radio spectrum for G46.8–0.3. The resulting spectrum exhibits a featureless power-law form with an exponent α = −0.535 ± 0.012. The lack of a spectral turnover at the lowest radio frequencies, which is observable in many other SNRs, excludes the presence of abundant ionised gas either proximate to the SNR itself or along its line of sight. The analysis of local changes in the radio spectral index across G46.8–0.3 suggests a tendency to slightly steepen approximately at 1 GHz. Even if this steepening is real, it does not impact the integrated spectrum of the source. Deeper imaging of the radio structures of G46.8–0.3 and spectral maps constructed from matched raw data are needed to provide new insights into the local spectral properties of the remnant. On the basis of the spectral properties of the atomic gas, we placed the remnant at 8.7 ± 1.0 kpc and we revisited the distance to the nearby H ii region G046.495–00.241 to 7.3 ± 1.2 kpc. From evolutionary models and our distance estimate, we conclude that G46.8–0.3 is a middle-aged (~1 × 104 yr) SNR. Furthermore, we recognise several 12CO and 13CO molecular structures in the proximity of the remnant. We used combined CO-H i profiles to derive the kinematic distances to these features and characterise their physical properties. We provide compelling evidence for environmental molecular clouds physically linked to G46.8–0.3 at its centre, on its eastern edge, and towards the northern and southwestern rims on the far side of the SNR shell. Our study of the molecular matter does not confirm that the remnant is embedded in a molecular cavity as previously suggested. G46.8–0.3 shows a line-of-sight coincidence with the γ-ray source 4FGL J1918.1+1215c detected at GeV energies by the space telescope Fermi. A rough analysis based on the properties of the interstellar matter close to G46.8–0.3 indicates that the GeV γ-ray photons detected in the direction to the SNR can be plausibly attributed to hadronic collisions and/or bremsstrahlung radiation.

Enhancement of heat transfer in shell and tube heat exchanger using mini-channels and nanofluids: An experimental study

This study aimed to experimentally investigate the effects of Al2O3-water nanofluids with six different volume concentrations (0.02%, 0.1%, 0.2%, 0.4%, 0.6%, and 0.8%) instead of water as working fluid on heat transfer and pressure drop on the tube side of a mini-channel shell and tube heat exchanger (MC-STHE). The shell-side hot fluid flow rate was kept constant at 180 L/h, while the flow rate of the tube-side cold fluids ranged from 125 to 600 L/h. The convective heat transfer coefficient (CHTC) of the nanofluids increased in the transition and turbulent regions. The nanofluids also extended the transition region. The nanofluids had higher friction factors than water. The nanofluids had an optimal volumetric concentration and a flow rate of 0.4% and 375 L/h, respectively, at which the CHTC enhanced by 49%, while the friction factor increased by 21% compared to water. Compared to macrotube heat exchangers, the CHTC enhanced 3 to 7 times with the combined effect of the mini-channels and nanofluids in the shell-and-tube heat exchanger (STHE). Consistent with earlier studies (maximum TEF of 1.8), the thermal enhancement factor (TEF) for the optimal volumetric concentration Al2O3-water nanofluid in the MC-STHE was 1.6 at most under the same hydrodynamic conditions. The performance evaluation criterion (PEC) and the efficiency evaluation criterion (EEC) showed that there was no point (not enhancement) in using nanofluids instead of the base fluid (water) in the MC-STHE.

Melting Enhancement in a Triple-Tube Latent Heat Storage System with Sloped Fins.

Due to the potential cost saving and minimal temperature stratification, the energy storage based on phase-change materials (PCMs) can be a reliable approach for decoupling energy demand from immediate supply availability. However, due to their high heat resistance, these materials necessitate the introduction of enhancing additives, such as expanded surfaces and fins, to enable their deployment in more widespread thermal and energy storage applications. This study reports on how circular fins with staggered distribution and variable orientations can be employed for addressing the low thermal response rates in a PCM (Paraffin RT-35) triple-tube heat exchanger consisting of two heat-transfer fluids flow in opposites directions through the inner and the outer tubes. Various configurations, dimensions, and orientations of the circular fins at different flow conditions of the heat-transfer fluid were numerically examined and optimized using an experimentally validated computational fluid-dynamic model. The results show that the melting rate, compared with the base case of finless, can be improved by 88% and the heat charging rate by 34%, when the fin orientation is downward–upward along the left side and the right side of the PCM shell. The results also show that there is a benefit if longer fins with smaller thicknesses are adopted in the vertical direction of the storage unit. This benefit helps natural convection to play a greater role, resulting in higher melting rates. Changing the fins’ dimensions from (thickness × length) 2 × 7.071 mm2 to 0.55 × 25.76 mm2 decreases the melting time by 22% and increases the heat charging rate by 9.6%. This study has also confirmed the importance of selecting the suitable values of Reynolds numbers and the inlet temperatures of the heat-transfer fluid for optimizing the melting enhancement potential of circular fins with downward–upward fin orientations.

Dynamic stiffness formulation and vibration analysis of coupled conical-ribbed cylindrical-conical shell structure with general boundary condition

In this paper, the dynamic stiffness method (DSM) is presented to investigate the vibration characterizes of coupled conical-ribbed cylindrical-conical shell structure with general boundary condition. Rib stiffeners are evenly distributed in the inner side of the cylindrical shell. Firstly, the coupled structure is divided into several components (i.e., conical and cylindrical shells, annular plate) according to the geometric properties and coupling boundary conditions. The displacement fields of the components are derived from the governing equations exactly. Then, the dynamic stiffness matrix is formulated based on the relationship between the displacements and forces on the boundaries of the components. The global dynamic stiffness matrix of the coupled structure is assembled in a similar way as used in the finite element method (FEM). In addition, the experimental model of conical-ribbed cylindrical-conical shell structure is built and vibration test is conducted. The accuracy and stability of the present method are validated by comparing the present results with the results obtained by FEM and experimental test. Several numerical examples are conducted to understand the effects of geometric parameters on the dynamic behaviors of the coupled structure, which can offer positive guides for acoustic design of the combined shell structure.

Performance of Heat Exchanger with Nanofluids

The effect of adding nanomaterial of aluminum oxide (Al2O3), titanium oxide (TiO2) and zirconium oxide (ZrO2) in different concentrations of 0.25, 0.5, 0.75, 1.0, and 1.25 g/L to the cold fluid (water) turbulently flowing with different flow rates of 75, 100, 125, 150, and 175 L/min in tube side countercurrently to hot water flowing with a constant flow rate of 60 L/min in the shell side of shell and tube heat exchanger on the heat transfer rates and overall heat transfer coefficients are experimentally studied. It is found that the addition of nanomaterials gives rise to outlet cold (nano) fluids temperatures causing to enhancement averagely 7.74, 11.25, and 17.38 percent for ZrO2, TiO2, and Al2O3 respectively in heat transfer rate and averagely 12.72, 19.47, and 28.71 percent for ZrO2, TiO2, and Al2O3 respectively in overall heat transfer coefficients. The maximum enhancement values in heat transfer rates and in overall heat transfer coefficients are attained at a flow rate of 150 L/min of cold fluid.

Double-sided modification of TiO2 spherical shell by graphene sheets with enhanced photocatalytic activity for CO2 reduction

TiO2 spherical shells with both inner and outer surface modified by graphene have been successfully constructed through a stepwise loading method. This double-sided modification method greatly increases the contact area of the shell with graphene sheets, which is beneficial for graphene to separate more photoelectrons from both the inner and outer sides of the shell simultaneously. The results of photocatalytic reduction of CO2 into CO indicate that the modification effects of inner and outer wall of TiO2 shell by graphene seem to be relatively independent to each other. As a result, compared with the traditional single-sided modified samples, even these optimal ones, the loading of graphene on the other side of TiO2 shell can still improve the photocatalytic reduction performance. Moreover, the optimal dosage of graphene on one side of shell surface is always maintained, without being affected by the graphene usage on the other side. This work indicates that the unique heterojunction obtained by graphene double-sided modification is advantageous to enhance the photocatalytic CO2 reduction performance and expected to be extended to the construction of other photocatalysts.

A theoretical solution of the axial stiffness of a cylindrical shell with a circular plate

A structure of a cylindrical shell with a circular plate end cap is usually used in connect different shaft system and it is necessary to estimate the axial stiffness in order to analyze the vibration of the rotor system. This paper builds the model of this structure. The theoretical solution of the bending deflection of the circular plate and the cylindrical shell are deduced by using the classic theory of plates and shells, and the continuity boundary conditions at the junction of the circular plate and the cylindrical shell. Furthermore, the axial stiffness of the structure is solved through considering the relationship between the external force-bending deformation. Two different boundary conditions for the left side of the cylindrical shell is considered and their axial stiffness varying with the length of the cylindrical shell is calculated. For verification, a finite element model of the structure is built and analyzed. The theoretical results fairly coincide with the finite element ones.

Evaluation of beeswax coated coconut shells for packaging of set-type dahi: an Indian fermented product.

An attempt was made to develop coconut shell-based eco-friendly packaging material for the packaging of set-type dahi. Beeswax was used to improve the moisture barrier properties of coconut shell (CS). UV treatment for 60min showed complete disinfection of the coconut shell surface. The top open side of the coconut shell was sealed with aluminium foil using pectin solution as adhesive. Set-type dahi was prepared and packaged in beeswax coated CS (BCCS) and evaluated for physico-chemical, textural, sensorial and microbiological quality changes for a period of 21days at 6 ± 1°C. The rate of increase in acidity was found slower in BCCS as compared to dahi packaged in polypropylene cups (control). There was no whey separation, consequently water-holding capacity and firmness of product were better in dahi packaged in BCCS. The sensorial analysis revealed better body and texture properties for dahi packaged in BCCS. However, the flavour score of dahi packaged in BCCS decreased comparatively after 12days due to the absorption of coconut flavor by the product. These findings demonstrated the potential of coconut shell based eco-friendly packaging material for packaging set-type dahi and thereby aim to reduce the use of non-biodegradable plastics.

Detailed comparison of the methods used in the heat transfer coefficient and pressure loss calculation of shell side of shell and tube heat exchangers with the experimental results

ABSTRACT In this study, results of HTRI Xchanger software used in the analysis of shell and tube heat exchangers (STHE), and Kern and Bell-Delaware methods, which are the conventional methods used for calculation of shell side heat transfer coefficient (SSHTC) and pressure loss (PL), were compared with experimental data. An experimental study was considered for Heat exchanger (HE) dimensions and fluid properties from literature. Then SSHTC and PL values were calculated using Kern and Bell-Delaware methods and HTRI Xchanger software for the measured shell side flowrates. SSHTC and PL values calculated for lower shell side mass flowrates by Kern method deviated from experimental results at low ratios. In addition, deviations in high flowrates values increasingly moved away from experimental results. In the Bell-Delaware method, although low deviations were observed in the high shell-side mass flowrates, the deviations increased at low flow rates and diverged from the experimental results. The deviation of SSHTC values calculated by the HTRI Xchanger program was found to be massively independent from the shell side flowrate. In addition, as in Bell-Delaware method, it has been observed that deviations in the shell side pressure loss (SSPL) calculations increased with increasing shell-side mass flowrate. As a result, SSHTC was calculated with average deviations of + 17, −11, and + 18%, by Kern and Bell-Delaware methods and HTRI Xchanger software respectively. Similarly, shell side PL was found with + 64, −25, and −32% average deviation, respectively.

Process-integrated steel ladle monitoring, based on infrared imaging – a robust approach to avoid ladle breakout

ABSTRACT Ladle breakout is a risky affair which is always present in steel making. The ladle breakout involves equipment damage and loss of production and sometimes loss of life. The present article describes the method of automatic detection of hotspot on the cold side of a ladle shell with the help of a group of infrared camera and subsequent processing of the infrared images in the LabVIEW platform. The system layout as implemented in the steel plant along with various pitfalls likely to be encountered during operation is discussed. Finally, the result of the trial run in the steel plant is presented. The system is found to be very effective as a preventive maintenance program to stop or minimise the ladle breakout.

Impact Mechanics of Football Helmet with Various Shell Liner Configurations

The structure of the skull reveals that the cranial is made up of a number of bones. These bones, except the temporomandibular joint, are joined by sutures. The adjacent bones are strongly united by a matrix of connective tissues consisting of bundles of strong collagenous fibres connecting periosteum to the bones. The little movement at the sutures contributes to the elasticity and compliance of the cranial. This composition serves as a shock absorber and distributes impact force evenly around the skull. Frequent head impacts by footballers cause concussion which leads to brain and neurological disorders such as; Traumatic Brain Injury (TBI), dementia, depression, and a loss of attention span. These disorders are primarily caused by shock waves following impact, which moves from the front to the back of the brain. As such, the effort is geared at reducing head injuries from concussion by optimising helmet design through shock absorption increase and stress amplification reduction during impact. In this paper, the suture structure is mimicked in the design of a football helmet. A fibre-reinforced composite liner is introduced in the shell of the helmet. The liner runs from the front to the back of the helmet and bisects the shell into two equal parts. Hyperelastic material model is employed in the modelling of the composite liner while the polycarbonate helmet shell is modelled as a nonlinear elastoplastic material. A finite element model based on realistic geometric features of a football helmet was carried out, and an explicit finite element code LS-DYNA® is employed to simulate dynamic responses at different impact velocities of the helmet. The simulation was repeated for various compositions of the composite liner. Impact loads are applied on one side of the helmet shell while the responses are taken on the other side of the shell body of the helmet. To establish the validity of the model, the liner, and the shell materials are made to be the same. The results revealed that the responses of the helmet during impact are the same when the two components are of the same material compared with when there is no liner on the helmet shell. It was also shown that the dynamic response curve of the helmet emanating from different impacting conditions is judged by the maximum principal stress, Von Mises stress, and acceleration monitored within the impact period. The helmet composition with a sinusoidal liner form on the shell absorbed more impact load than other liner configurations.

Transient behavior of 5 kW class shell-and-tube methane steam reformer with intermediate temperature heat source

A 5 kW class shell and tube methane steam reformer with intermediate temperature heat source was evaluated for the efficiency boost up of high temperature fuel cell system. The shell side of shell and tube steam reformer is consisted of inlet compartment, outlet compartment and reforming zone. Tube sides are filled with 37 tubes to maximize the heat transfer area between the reforming zone and heat source zone. Among the various operational conditions of the reformer, reformer reactants flow rate, steam to carbon ratio, reformer inlet temperature, and heat source inlet temperature are changed to find the crucial factor on low temperature reforming reaction. Additionally, transient behavior of the reformer is considered during the start-up of methane steam reforming reaction at low temperature. The results show that the main factors for affecting the performance of the reformer are load and heat source inlet temperature.

Fractal branch-like fractal shell-and-tube heat exchangers: A CFD study of the shell side performance

Nature has provided some of the most ingenious and elegant solutions to complex problems over millions of years of refining through evolution. The adaptation of Nature s solutions to engineering problems is a recent trend which has opened opportunities for improvement in many areas ranging from Architecture to Chemical Engineering. In particular, the use of fractal geometries on heat exchangers is a recent design trend. Recent investigations highlight the benefit of implementing fractal-based geometries on the tube side of shell and tube heat exchangers. A complete evaluation of such devices by assessing the performance of the shell side has not been undertaken, though. Here, we present a systematic numerical assessment of the shell side of a tree-like shaped heat exchanger. Key performance parameters, i.e. temperature change, pressure drop and coefficient of performance, are obtained and compared to those of a straight tube, in order to fully understand the potential of the application of fractal-based shapes to the design of heat exchangers.

A comprehensive second law analysis of coil side air injection in the shell and coiled tube heat exchanger: An experimental study

Recently, the use of air injection into heat exchangers to increase their thermal performance has attracted great attention. In the present study, air is injected into the coil side of a horizontal shell and coiled tube heat exchanger. An external unit for air bubbles injection is used. By means of this method, there is no need to modify the original design of the heat exchanger. The effect of various air volume fractions (VF) on the number of thermal units (NTU) and pressure drop is examined. Besides, the effect of air bubbles injection is analyzed from the viewpoints of the second law of thermodynamics, which has not been performed previously. The entropy generation, augmentation entropy generation number and Witte-Shamsundar efficiency as important criteria are analyzed for the developed system. The results revealed that air bubbles injection into the coil side improved the thermal characteristics of the heat exchanger. Also it was observed that for achieving the best performance the volume fraction should be optimized. Besides, according to the second law analysis, it is realized that air bubbles injection into the coil side is more effective method for the heat exchangers with high liquid flow rates.

Effect of nano silver coating on thermal protective performance of firefighter protective clothing

The main aim of this experimental work is to find out possible improvement in thermal protective performance of firefighter protective clothing when subjected to different level of radiant heat flux density. Firefighter protective clothing normally consists of three layers: outer shell, moisture barrier and thermal liner. When thermal protective performance of firefighter protective clothing is enhanced, the time of exposure against radiant heat flux is increased, which will provide extra amount of time to firefighter to carry on their work without suffering from severe skin burn injuries. In this study, the exterior side of outer shell was coated with nano-silver metallic particle through magnetron sputtering technology. Coating of outer shell with nano-silver particles was performed at three level of thickness, i.e. 1, 2 and 3 µm, respectively. All the uncoated and silver coated specimens were then characterized on air permeability tester, Permetest and radiant heat transmission machine. It was observed that coating has insignificant difference on the air and water vapor permeability of specimen and a significant decline was recorded for the value of transmitted heat flux density Qc (kW/m2) and percentage transmission factor (%TF Qo) as compared to uncoated specimen when subjected to 10 kW/m2 and 20 kW/m2 indicating improvement of thermal protective performance. These values go on further reduction with increase in thickness of coating layer of nano-silver particles.

Experimental investigation of heat transfer and pressure drop in a mini-channel shell and tube heat exchanger

This study experimentally investigated heat transfer and pressure drop on tube side of a mini-channel shell and tube heat exchanger (MC-STHE) prototype designed and manufactured using Kern method. Mini-channel copper tubes with an inner diameter of 2 mm and a length of 240 mm were used on the tube side of the MC-STHE. Baffles with a 25% baffle cut and a shell with an inner diameter of 30 mm were used on the shell side. The Reynolds number on the tube side was changed from 1000 to 10,000 while that on the shell side was kept constant at 680. The experimental convective heat transfer coefficients and friction factors for the tube side were compared with correlations for macro-pipes commonly used in the literature. The experimental convective heat transfer coefficients were in good agreement with the Shah and Sieder-Tate correlations in the laminar region and in good agreement with the Petukhov, Hausen and Gnielinski correlations in the transition region while the experimental friction factors showed a similar tendency to the correlation modified by Shah. In addition, the Nusselt number and friction factor correlations have been proposed for use in designing similar MC-STHEs. The optimal operating range of Reynolds number for MC-STHEs is 4000 < Re <5000 based on the Colburn factor while it is 4000 < Re <6000 based on the flow area goodness factor.

Вивчення оптичної щільності щелепових кісток у хворих із радикулярними кістами на тлі остеопорозу та без порушень мінерального обміну

There is a signifi cant scientifi c and practical interest in the study of bone mineral density in the jaw destructive processes caused by tumors in patients without bone remodeling disorders on the background of osteoporosis.The aim of the study – to conduct a comparative evaluation of jaw bone optical density in areas adjacent to radicular cysts depending on the osteoregenerating status of patients.Materials and Methods. 45 patients (20 males and 25 females) aged 20 to 70 years with radicular jaw cysts who were on an outpatient treatment at the Surgical Department of the Medical Stomatological Center of Danylo Halytskyi Lviv National Medical University were examined. Determination of bone mineral density (BMD) in patients was conducted by ultrasound bone densitometer Achilles (LUNAR Corp. (USA)) by measuring the time of ultrasonic waves pass through the calcaneus. Bone mineral density in patients was analyzed for the Z criterion. All patients underwent standard orthopantomograms on an X-ray apparatus Orthophos XG (Sirona). For the qualitative characteristics of mandibular cortical layer we used MCI index (mandibular cortical index) by Klemetti E. et al. (1994). According to published data, the index serves as an indicator of MCI systematic reduction of mineral density of the facial skeleton. Digital orthopantomograms analyzed by using the ImageJ software, which allows measuring the optical density of bone tissue at any selected jawbone area in standard brightness units in grayscale from 0 to 256 (the minimum values correspond to the background of the radiographs). The optical density of bone tissue was determined in a region directly adjacent to the shell of the radicular cyst, and compared with the intact bone on the symmetrical side of the jaw. Statistical analysis of the research results was carried out by a computer program of statistical calculation Statistica 8.Results and Discussion. As a result of ultrasound densitometry of the calcaneus in 17 women aged 45 to 60 years, we found signs of osteopenia and osteoporosis. Indicators of BMD within the age norm were detectedin 6 surveyed women who were younger than 45 years. Among the surveyed men of all ages signs of age norms were found much more frequently – in 11 cases. The MCI mandible index is in 87 % of cases directly correlated with state of bone mineral density determined by ultrasound densitometry, which is being consisted with literature data. In the absence of systemic disorders of mineral metabolism, the parameters of optical density in areas adjacent to the shells of the radicular cysts were higher compared to intact bones (p &lt;0.05), which, in our opinion, testifi es about the compensatory reaction of the bone tissue that is subjected to pathological infl uence (compression) from the side of the cyst shell. On the background of systemic osteoporosis, optic density of jaw bones in the area of injury compared to intact sides is decreased.Conclusions. Determination of the optical density of the jaw bones adjacent to the radicular cysts can be used as a screening test for the study of osteo-regenerative potential in patients and should be taken into account when choosing surgical treatment methods.